WorldWideScience

Sample records for tumor hypoxia blocks

  1. Blocking heme oxygenase-1 by zinc protoporphyrin reduces tumor hypoxia-mediated VEGF release and inhibits tumor angiogenesis as a potential therapeutic agent against colorectal cancer.

    Science.gov (United States)

    Cheng, Chun-Chia; Guan, Siao-Syun; Yang, Hao-Jhih; Chang, Chun-Chao; Luo, Tsai-Yueh; Chang, Jungshan; Ho, Ai-Sheng

    2016-01-28

    Hypoxia in tumor niche is one of important factors to start regeneration of blood vessels, leading to increase survival, proliferation, and invasion in cancer cells. Under hypoxia microenvironment, furthermore, steadily increased hypoxia-inducible factor -1α (HIF-1α) is observed, and can increase vascular endothelial growth factor (VEGF) expression and promote angiogenesis. Zinc protoporphyrin (ZnPP), a heme oxygenase-1 (HO-1) inhibitor, is potential to inhibit tumor proliferation and progression. However, the mechanism of ZnPP in inhibition of tumor is not completely clear. We hypothesize that ZnPP may modulate HIF-1α through inhibiting HO-1, and then inhibit angiogenesis and tumor progression. This study aimed to dissect the mechanism of ZnPP in tumor suppression. We observed the amount of VEGF was increased in the sera of the colorectal cancer (CRC) patients (n = 34, p ZnPP inhibited the expressions of HIF-1α and VEGF coupled with cell proliferations of HCT-15 cells, suggesting that ZnPP blocked HIF-1α expression, and then inhibited the consequent VEGF production. In the xenograft model, we also observed that the animals exposed to ZnPP displayed much smaller tumor nodules and less degree of angiogenesis with decreased expression of the angiogenesis marker, αvβ3 integrin, compared to that in normal control. This study demonstrated that VEGF level in serum was elevated in the patients with CRC. The HO-1 inhibitor, ZnPP, possessed the properties of anti-tumor agent by decreasing HIF-1α levels, blocking VEGF production, impairing tumor angiogenesis, and inhibiting tumor growth.

  2. Blocking heme oxygenase-1 by zinc protoporphyrin reduces tumor hypoxia-mediated VEGF release and inhibits tumor angiogenesis as a potential therapeutic agent against colorectal cancer

    OpenAIRE

    Cheng, Chun-Chia; Guan, Siao-Syun; Yang, Hao-Jhih; Chang, Chun-Chao; Luo, Tsai-Yueh; Chang, Jungshan; Ho, Ai-Sheng

    2016-01-01

    Background Hypoxia in tumor niche is one of important factors to start regeneration of blood vessels, leading to increase survival, proliferation, and invasion in cancer cells. Under hypoxia microenvironment, furthermore, steadily increased hypoxia-inducible factor-1? (HIF-1?) is observed, and can increase vascular endothelial growth factor (VEGF) expression and promote angiogenesis. Zinc protoporphyrin (ZnPP), a heme oxygenase-1 (HO-1) inhibitor, is potential to inhibit tumor proliferation a...

  3. Bayesian Inference of Tumor Hypoxia

    Science.gov (United States)

    Gunawan, R.; Tenti, G.; Sivaloganathan, S.

    2009-12-01

    Tumor hypoxia is a state of oxygen deprivation in tumors. It has been associated with aggressive tumor phenotypes and with increased resistance to conventional cancer therapies. In this study, we report on the application of Bayesian sequential analysis in estimating the most probable value of tumor hypoxia quantification based on immunohistochemical assays of a biomarker. The `gold standard' of tumor hypoxia assessment is a direct measurement of pO2 in vivo by the Eppendorf polarographic electrode, which is an invasive technique restricted to accessible sites and living tissues. An attractive alternative is immunohistochemical staining to detect proteins expressed by cells during hypoxia. Carbonic anhydrase IX (CAIX) is an enzyme expressed on the cell membrane during hypoxia to balance the immediate extracellular microenvironment. CAIX is widely regarded as a surrogate marker of chronic hypoxia in various cancers. The study was conducted with two different experimental procedures. The first data set was a group of three patients with invasive cervical carcinomas, from which five biopsies were obtained. Each of the biopsies was fully sectioned and from each section, the proportion of CAIX-positive cells was estimated. Measurements were made by image analysis of multiple deep sections cut through these biopsies, labeled for CAIX using both immunofluorescence and immunohistochemical techniques [1]. The second data set was a group of 24 patients, also with invasive cervical carcinomas, from which two biopsies were obtained. Bayesian parameter estimation was applied to obtain a reliable inference about the proportion of CAIX-positive cells within the carcinomas, based on the available biopsies. From the first data set, two to three biopsies were found to be sufficient to infer the overall CAIX percentage in the simple form: best estimate±uncertainty. The second data-set led to a similar result in 70% of the cases. In the remaining cases Bayes' theorem warned us

  4. Immunohistochemical Detection of Changes in Tumor Hypoxia

    International Nuclear Information System (INIS)

    Russell, James; Carlin, Sean; Burke, Sean A.; Wen Bixiu; Yang, Kwang Mo; Ling, C. Clifton

    2009-01-01

    Purpose: Although hypoxia is a known prognostic factor, its effect will be modified by the rate of reoxygenation and the extent to which the cells are acutely hypoxic. We tested the ability of exogenous and endogenous markers to detect reoxygenation in a xenograft model. Our technique might be applicable to stored patient samples. Methods and Materials: The human colorectal carcinoma line, HT29, was grown in nude mice. Changes in tumor hypoxia were examined by injection of pimonidazole, followed 24 hours later by EF5. Cryosections were stained for these markers and for carbonic anhydrase IX (CAIX) and hypoxia-inducible factor 1α (HIF1α). Tumor hypoxia was artificially manipulated by carbogen exposure. Results: In unstressed tumors, all four markers showed very similar spatial distributions. After carbogen treatment, pimonidazole and EF5 could detect decreased hypoxia. HIF1α staining was also decreased relative to CAIX, although the effect was less pronounced than for EF5. Control tumors displayed small regions that had undergone spontaneous changes in tumor hypoxia, as judged by pimonidazole relative to EF5; most of these changes were reflected by CAIX and HIF1α. Conclusion: HIF1α can be compared with either CAIX or a previously administered nitroimidazole to provide an estimate of reoxygenation

  5. The Clinical Importance of Assessing Tumor Hypoxia: Relationship of Tumor Hypoxia to Prognosis and Therapeutic Opportunities

    Science.gov (United States)

    Walsh, Joseph C.; Lebedev, Artem; Aten, Edward; Madsen, Kathleen; Marciano, Liane

    2014-01-01

    I. Introduction II. The Clinical Importance of Tumor Hypoxia A. Pathophysiology of hypoxia B. Hypoxia's negative impact on the effectiveness of curative treatment 1. Hypoxic tumors accumulate and propagate cancer stem cells 2. Hypoxia reduces the effectiveness of radiotherapy 3. Hypoxia increases metastasis risk and reduces the effectiveness of surgery 4. Hypoxic tumors are resistant to the effects of chemotherapy and chemoradiation C. Hypoxia is prognostic for poor patient outcomes III. Diagnosis of Tumor Hypoxia A. Direct methods 1. Oxygen electrode—direct pO2 measurement most used in cancer research 2. Phosphorescence quenching—alternative direct pO2 measurement 3. Electron paramagnetic resonance 4. 19F-magnetic resonance spectroscopy 5. Overhauser-enhanced MRI B. Endogenous markers of hypoxia 1. Hypoxia-inducible factor-1α 2. Carbonic anhydrase IX 3. Glucose transporter 1 4. Osteopontin 5. A combined IHC panel of protein markers for hypoxia 6. Comet assay C. Physiologic methods 1. Near-infrared spectroscopy/tomography—widely used for pulse oximetry 2. Photoacoustic tomography 3. Contrast-enhanced color duplex sonography 4. MRI-based measurements 5. Blood oxygen level-dependent MRI 6. Pimonidazole 7. EF5 (pentafluorinated etanidazole) 8. Hypoxia PET imaging—physiologic hypoxia measurement providing tomographic information a. 18F-fluoromisonidazole b. 18F-fluoroazomycinarabinofuranoside c. 18F-EF5 (pentafluorinated etanidazole) d. 18F-flortanidazole e. Copper (II) (diacetyl-bis (N4-methylthiosemicarbazone)) f. 18F-FDG imaging of hypoxia IV. Modifying Hypoxia to Improve Therapeutic Outcomes A. Use of hypoxia information in radiation therapy planning B. Use of hypoxia assessment for selection of patients responsive to nimorazole C. Use of hypoxia assessment for selection of patients responsive to tirapazamine D. Use of hypoxia assessment for selection of patients

  6. Optical imaging of tumor hypoxia dynamics

    Science.gov (United States)

    Palmer, Gregory M.; Fontanella, Andrew N.; Zhang, Guoqing; Hanna, Gabi; Fraser, Cassandra L.; Dewhirst, Mark W.

    2010-11-01

    The influence of the tumor microenvironment and hypoxia plays a significant role in determining cancer progression, treatment response, and treatment resistance. That the tumor microenvironment is highly heterogeneous with significant intratumor and intertumor variability presents a significant challenge in developing effective cancer therapies. Critical to understanding the role of the tumor microenvironment is the ability to dynamically quantify oxygen levels in the vasculature and tissue in order to elucidate the roles of oxygen supply and consumption, spatially and temporally. To this end, we describe the use of hyperspectral imaging to characterize hemoglobin absorption to quantify hemoglobin content and oxygen saturation, as well as dual emissive fluorescent/phosphorescent boron nanoparticles, which serve as ratiometric indicators of tissue oxygen tension. Applying these techniques to a window-chamber tumor model illustrates the role of fluctuations in hemoglobin saturation in driving changes in tissue oxygenation, the two being significantly correlated (r = 0.77). Finally, a green-fluorescence-protein reporter for hypoxia inducible factor-1 (HIF-1) provides an endpoint for hypoxic stress in the tumor, which is used to demonstrate a significant association between tumor hypoxia dynamics and HIF-1 activity in an in vivo demonstration of the technique.

  7. Pimonidazole: a novel hypoxia marker for complementary study of tumor hypoxia and tumor biology

    International Nuclear Information System (INIS)

    Varia, Mahesh A.; Kennedy, Andrew S.; Calkins-Adams, Dennise P.; Rinker, Lillian; Novotny, Debra; Fowler, Wesley C.; Raleigh, James A.

    1997-01-01

    Purpose/Objectives: Tumor hypoxia appears to be associated with treatment resistance and with gene expression that may lead to hypoxia-mediated selection of tumor cells as a source for cell growth and metastases. The objective of this study was to develop complementary techniques of hypoxia detection with molecular markers of cell proliferation and metastases in order to investigate the role of tumor hypoxia in tumor biology. Materials and Methods: Pimonidazole is a 2-nitroimidazole which is reductively-activated and becomes covalently bound to thiol-containing proteins only in hypoxic cells. These adducts can be detected using immunohistochemistry, enzyme linked immunosorbent assay or flow cytometry as a measure of hypoxia in tumors. Quantitative immunohistochemical analysis has been completed for five patients with squamous cell carcinoma of the cervix who were given pimonidazole hydrochloride (0.5 g/m 2 intravenously) followed by cervical biopsies 24 hours later. Informed consent was obtained according to a protocol approved by the Institutional Review Board. A minimum of 3 random biopsies were obtained from the tumors and at least four sections examined from each biopsy site. Formalin fixed, paraffin embedded tissue sections were immunostained for pimonidazole binding using a mouse monoclonal antibody. Commercially available monoclonal antibodies were used to detect cell proliferation markers MIB-1 (Ki-67) and to detect vascular endothelial growth factor (VEGF) in tumor cells in contiguous sections. The extent of immunostaining was expressed as the percent of immunostained to total tumor cells as determined by Chalkley point counting. Results: No clinical toxicities were associated with pimonidazole infusion. Immunostaining with pimonidazole antibody was observed in all patients indicating the presence of tumor hypoxia. Qualitatively there is little or no overlap between the areas of hypoxia and proliferation. Quantitative data tabulated below show the

  8. Tumor Hypoxia: Causative Mechanisms, Microregional Heterogeneities, and the Role of Tissue-Based Hypoxia Markers.

    Science.gov (United States)

    Vaupel, Peter; Mayer, Arnulf

    Tumor hypoxia is a hallmark of solid malignant tumor growth, profoundly influences malignant progression and contributes to the development of therapeutic resistance. Pathogenesis of tumor hypoxia is multifactorial, with contributions from both acute and chronic factors. Spatial distribution of hypoxia within tumors is markedly heterogeneous and often changes over time, e.g., during a course of radiotherapy. Substantial changes in the oxygenation status can occur within the distance of a few cell layers, explaining the inability of currently used molecular imaging techniques to adequately assess this crucial trait. Due to the possible importance of tumor hypoxia for clinical decision-making, there is a great demand for molecular tools which may provide the necessary resolution down to the single cell level. Exogenous and endogenous markers of tumor hypoxia have been investigated for this purpose. Their potential use may be greatly enhanced by multiparametric in situ methods in experimental and human tumor tissue.

  9. Cycling hypoxia: A key feature of the tumor microenvironment.

    Science.gov (United States)

    Michiels, Carine; Tellier, Céline; Feron, Olivier

    2016-08-01

    A compelling body of evidence indicates that most human solid tumors contain hypoxic areas. Hypoxia is the consequence not only of the chaotic proliferation of cancer cells that places them at distance from the nearest capillary but also of the abnormal structure of the new vasculature network resulting in transient blood flow. Hence two types of hypoxia are observed in tumors: chronic and cycling (intermittent) hypoxia. Most of the current work aims at understanding the role of chronic hypoxia in tumor growth, response to treatment and metastasis. Only recently, cycling hypoxia, with spatial and temporal fluctuations in oxygen levels, has emerged as another key feature of the tumor environment that triggers different responses in comparison to chronic hypoxia. Either type of hypoxia is associated with distinct effects not only in cancer cells but also in stromal cells. In particular, cycling hypoxia has been demonstrated to favor, to a higher extent than chronic hypoxia, angiogenesis, resistance to anti-cancer treatments, intratumoral inflammation and tumor metastasis. These review details these effects as well as the signaling pathway it triggers to switch on specific transcriptomic programs. Understanding the signaling pathways through which cycling hypoxia induces these processes that support the development of an aggressive cancer could convey to the emergence of promising new cancer treatments. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Endogenous markers of tumor hypoxia. Predictors of clinical radiation resistance?

    International Nuclear Information System (INIS)

    Vordermark, D.; Brown, J.M.

    2003-01-01

    Background: Eppendorf electrode measurements of tumor oxygenation have defined an adverse effect of tumor hypoxia on prognosis after radiotherapy and other treatment modalities, in particular in head and neck and cervix carcinomas as well as soft tissue sarcomas. Recently, the immunohistochemical detection of proteins involved in the ''hypoxic response'' of tumor cells has been discussed as a method to estimate hypoxia in clinical tumor specimens. Material and Methods: This review focuses on clinical and experimental data, regarding prognostic impact and comparability with other methods of hypoxia detection, for three proteins suggested as endogenous markers of tumor hypoxia: hypoxia-inducible factor-1α (HIF-1α), carbonic anhydrase 9 (CA 9), and glucose transporter 1 (GLUT1). Results: None of the three potential hypoxia markers is exclusively hypoxia-specific, and in each case protein can be detected under normoxic conditions in vitro. HIF-1α responds rapidly to hypoxia but also to reoxygenation, making this marker quite unstable in the context of clinical sample collection. The perinecrotic labeling pattern typical of chronic hypoxia and a reasonable agreement with injectable hypoxia markers such as pimonidazole have most consistently been described for CA 9. All three markers showed correlation with Eppendorf electrode measurements of tumor oxygenation in carcinoma of the cervix. In nine of 13 reports, among them all three that refer to curative radiotherapy for head and neck cancer, HIF-1α overexpression was associated with poor outcome. CA 9 was an adverse prognostic factor in cervix, head and neck and lung cancer, but not in two other head and neck cancer reports. GLUT1 predicted for poor survival in colorectal, cervix and lung cancer. Conclusion: Endogenous markers have the potential to indicate therapeutically relevant levels of hypoxia within tumors. Clinical trials assessing a marker's ability to predict a benefit from specific hypoxia

  11. Target tumor hypoxia with 2-nitroimidazole-ICG dye conjugates

    Science.gov (United States)

    Xu, Yan; Zanganeh, Saeid; Mohammad, Innus; Aguirre, Andres; Wang, Tianheng; Yang, Yi; Kuhn, Liisa; Smith, Michael; Zhu, Quing

    2013-03-01

    In this paper, we have synthesized a second generation tumor hypoxia targeted 2-nitroimidazole-ICG conjugate using piperazine linker (2-nitro-ICG-p) and validated its performance in in vivo tumor targeting. The results have shown that tumor hypoxia can be targeted with twice higher signal strength beyond three hours post-injection while the un-targeted ICG has completely washed out. The improvement of the second generation 2-nitro-ICG-p dyes is 1.2-1.3 times over the first generation 2-nitro-ICG dyes using ethanol linker beyond 3 hours post-injection which is the optimal time-window for evaluating tumor hypoxia.

  12. Tumor hypoxia and reoxygenation: the yin and yang for radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Beom Ju; Kim, Jong Woo; Jeong, Hoi Bin; Bok, Seo Yeon; Kim, Young Eun; Ahn, G One [Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang (Korea, Republic of)

    2016-12-15

    Tumor hypoxia, a common feature occurring in nearly all human solid tumors is a major contributing factor for failures of anticancer therapies. Because ionizing radiation depends heavily on the presence of molecular oxygen to produce cytotoxic effect, the negative impact of tumor hypoxia had long been recognized. In this review, we will highlight some of the past attempts to overcome tumor hypoxia including hypoxic radiosensitizers and hypoxia-selective cytotoxin. Although they were (still are) a very clever idea, they lacked clinical efficacy largely because of ‘reoxygenation’ phenomenon occurring in the conventional low dose hyperfractionation radiotherapy prevented proper activation of these compounds. Recent meta-analysis and imaging studies do however indicate that there may be a significant clinical benefit in lowering the locoregional failures by using these compounds. Latest technological advancement in radiotherapy has allowed to deliver high doses of radiation conformally to the tumor volume. Although this technology has brought superb clinical responses for many types of cancer, recent modeling studies have predicted that tumor hypoxia is even more serious because ‘reoxygenation’ is low thereby leaving a large portion of hypoxic tumor cells behind. Wouldn’t it be then reasonable to combine hypoxic radiosensitizers and/or hypoxia-selective cytotoxin with the latest radiotherapy? We will provide some preclinical and clinical evidence to support this idea hoping to revamp an enthusiasm for hypoxic radiosensitizers or hypoxia-selective cytotoxins as an adjunct therapy for radiotherapy.

  13. Low Molecular Weight Fucoidan Inhibits Tumor Angiogenesis through Downregulation of HIF-1/VEGF Signaling under Hypoxia

    Directory of Open Access Journals (Sweden)

    Meng-Chuan Chen

    2015-07-01

    Full Text Available Activation of hypoxia-induced hypoxia-inducible factors-1 (HIF-1 plays a critical role in promoting tumor angiogenesis, growth and metastasis. Low molecular weight fucoidan (LMWF is prepared from brown algae, and exhibits anticancer activity. However, whether LMWF attenuates hypoxia-induced angiogenesis in bladder cancer cells and the molecular mechanisms involved remain unclear. This is the first study to demonstrate that LMWF can inhibit hypoxia-stimulated H2O2 formation, HIF-1 accumulation and transcriptional activity vascular endothelial growth factor (VEGF secretion, and the migration and invasion in hypoxic human bladder cancer cells (T24 cells. LMWF also downregulated hypoxia-activated phosphorylation of PI3K/AKT/mTOR/p70S6K/4EBP-1 signaling in T24 cells. Blocking PI3K/AKT or mTOR activity strongly diminished hypoxia-induced HIF-1α expression and VEGF secretion in T24 cells, supporting the involvement of PI3K/AKT/mTOR in the induction of HIF-1α and VEGF. Additionally, LMWF significantly attenuated angiogenesis in vitro and in vivo evidenced by reduction of tube formation of hypoxic human umbilical vascular endothelial cells and blood capillary generation in the tumor. Similarly, administration of LMWF also inhibited the HIF-1α and VEGF expression in vivo, accompanied by a reduction of tumor growth. In summary, under hypoxia conditions, the antiangiogenic activity of LMWF in bladder cancer may be associated with suppressing HIF-1/VEGF-regulated signaling pathway.

  14. Hypoxia promotes tumor growth in linking angiogenesis to immune escape

    Directory of Open Access Journals (Sweden)

    Salem eCHOUAIB

    2012-02-01

    Full Text Available Despite the impressive progress over the past decade, in the field of tumor immunology, such as the identification of tumor antigens and antigenic peptides as potential targets, there are still many obstacles in eliciting an effective immune response to eradicate cancer. It has become increasingly clear that tumor microenvironment plays a crucial role in the control of immune protection and contains many overlapping mechanisms to evade antigen specific immunotherapy. Obviously, tumors have evolved to utilize hypoxic stress to their own advantage by activating key biochemical and cellular pathways that are important in progression, survival and metastasis. Among the hypoxia-induced genes, hypoxia-inducible factor (HIF-1 and vascular endothelial growth factor (VEGF play a determinant role in promoting tumor cell growth and survival. In this regard, hypoxia is emerging as an attractive target for cancer therapy. How the microenvironmental hypoxia poses both obstacles and opportunities for new therapeutic immune interventions will be discussed.

  15. Tumor suppressor p53 negatively regulates glycolysis stimulated by hypoxia through its target RRAD

    Science.gov (United States)

    Wu, Rui; Liang, Yingjian; Lin, Meihua; Liu, Jia; Chan, Chang S.; Hu, Wenwei; Feng, Zhaohui

    2014-01-01

    Cancer cells display enhanced glycolysis to meet their energetic and biosynthetic demands even under normal oxygen concentrations. Recent studies have revealed that tumor suppressor p53 represses glycolysis under normoxia as a novel mechanism for tumor suppression. As the common microenvironmental stress for tumors, hypoxia drives the metabolic switch from the oxidative phosphorylation to glycolysis, which is crucial for survival and proliferation of cancer cells under hypoxia. The p53's role and mechanism in regulating glycolysis under hypoxia is poorly understood. Here, we found that p53 represses hypoxia-stimulated glycolysis in cancer cells through RRAD, a newly-identified p53 target. RRAD expression is frequently decreased in lung cancer. Ectopic expression of RRAD greatly reduces glycolysis whereas knockdown of RRAD promotes glycolysis in lung cancer cells. Furthermore, RRAD represses glycolysis mainly through inhibition of GLUT1 translocation to the plasma membrane. Under hypoxic conditions, p53 induces RRAD, which in turn inhibits the translocation of GLUT1 and represses glycolysis in lung cancer cells. Blocking RRAD by siRNA greatly abolishes p53's function in repressing glycolysis under hypoxia. Taken together, our results revealed an important role and mechanism of p53 in antagonizing the stimulating effect of hypoxia on glycolysis, which contributes to p53's function in tumor suppression. PMID:25114038

  16. Hypoxia increases tumor cell shedding of MHC class I chain-related molecule: role of nitric oxide.

    Science.gov (United States)

    Siemens, D Robert; Hu, Nianping; Sheikhi, Abdol Karim; Chung, Eugene; Frederiksen, Lisa J; Pross, Hugh; Graham, Charles H

    2008-06-15

    The MHC class I chain-related (MIC) molecules play important roles in tumor immune surveillance through their interaction with the NKG2D receptor on natural killer and cytotoxic T cells. Thus, shedding of the MIC molecules from the tumor cell membrane represents a potential mechanism of escape from NKG2D-mediated immune surveillance. Tumor hypoxia is associated with a poor clinical outcome for cancer patients. We show that hypoxia contributes to tumor cell shedding of MIC through a mechanism involving impaired nitric oxide (NO) signaling. Whereas hypoxia increased MIC shedding in human prostate cancer cells, activation of NO signaling inhibited hypoxia-mediated MIC shedding. Similar to incubation in hypoxia, pharmacologic inhibition of endogenous NO signaling increased MIC shedding. Parallel studies showed hypoxia-mediated tumor cell resistance to lysis by interleukin 2-activated peripheral blood lymphocytes (PBL) and NO-mediated attenuation of this resistance to lysis. Inhibition of NO production also led to resistance to PBL-mediated lysis. Interference of MIC-NKG2D interaction with a blocking anti-MIC antibody abrogated the effect of hypoxia and NO signaling on tumor cell sensitivity to PBL-mediated lysis. Finally, continuous transdermal delivery of the NO mimetic glyceryl trinitrate (7.3 mug/h) attenuated the growth of xenografted MIC-expressing human prostate tumors. These findings suggest that the hypoxic tumor microenvironment contributes to resistance to immune surveillance and that activation of NO signaling is of potential use in cancer immunotherapy.

  17. Disrupting Hypoxia-Induced Bicarbonate Transport Acidifies Tumor Cells and Suppresses Tumor Growth.

    Science.gov (United States)

    McIntyre, Alan; Hulikova, Alzbeta; Ledaki, Ioanna; Snell, Cameron; Singleton, Dean; Steers, Graham; Seden, Peter; Jones, Dylan; Bridges, Esther; Wigfield, Simon; Li, Ji-Liang; Russell, Angela; Swietach, Pawel; Harris, Adrian L

    2016-07-01

    Tumor hypoxia is associated clinically with therapeutic resistance and poor patient outcomes. One feature of tumor hypoxia is activated expression of carbonic anhydrase IX (CA9), a regulator of pH and tumor growth. In this study, we investigated the hypothesis that impeding the reuptake of bicarbonate produced extracellularly by CA9 could exacerbate the intracellular acidity produced by hypoxic conditions, perhaps compromising cell growth and viability as a result. In 8 of 10 cancer cell lines, we found that hypoxia induced the expression of at least one bicarbonate transporter. The most robust and frequent inductions were of the sodium-driven bicarbonate transporters SLC4A4 and SLC4A9, which rely upon both HIF1α and HIF2α activity for their expression. In cancer cell spheroids, SLC4A4 or SLC4A9 disruption by either genetic or pharmaceutical approaches acidified intracellular pH and reduced cell growth. Furthermore, treatment of spheroids with S0859, a small-molecule inhibitor of sodium-driven bicarbonate transporters, increased apoptosis in the cell lines tested. Finally, RNAi-mediated attenuation of SLC4A9 increased apoptosis in MDA-MB-231 breast cancer spheroids and dramatically reduced growth of MDA-MB-231 breast tumors or U87 gliomas in murine xenografts. Our findings suggest that disrupting pH homeostasis by blocking bicarbonate import might broadly relieve the common resistance of hypoxic tumors to anticancer therapy. Cancer Res; 76(13); 3744-55. ©2016 AACR. ©2016 American Association for Cancer Research.

  18. Endogenous markers of tumor hypoxia. Predictors of clinical radiation resistance?

    Energy Technology Data Exchange (ETDEWEB)

    Vordermark, D. [Dept. of Radiation Oncology, Univ. of Wuerzburg (Germany); Dept. of Radiation Oncology, Stanford Univ. School of Medicine, Stanford, CA (United States); Brown, J.M. [Dept. of Radiation Oncology, Stanford Univ. School of Medicine, Stanford, CA (United States)

    2003-12-01

    Background: Eppendorf electrode measurements of tumor oxygenation have defined an adverse effect of tumor hypoxia on prognosis after radiotherapy and other treatment modalities, in particular in head and neck and cervix carcinomas as well as soft tissue sarcomas. Recently, the immunohistochemical detection of proteins involved in the ''hypoxic response'' of tumor cells has been discussed as a method to estimate hypoxia in clinical tumor specimens. Material and Methods: This review focuses on clinical and experimental data, regarding prognostic impact and comparability with other methods of hypoxia detection, for three proteins suggested as endogenous markers of tumor hypoxia: hypoxia-inducible factor-1{alpha} (HIF-1{alpha}), carbonic anhydrase 9 (CA 9), and glucose transporter 1 (GLUT1). Results: None of the three potential hypoxia markers is exclusively hypoxia-specific, and in each case protein can be detected under normoxic conditions in vitro. HIF-1{alpha} responds rapidly to hypoxia but also to reoxygenation, making this marker quite unstable in the context of clinical sample collection. The perinecrotic labeling pattern typical of chronic hypoxia and a reasonable agreement with injectable hypoxia markers such as pimonidazole have most consistently been described for CA 9. All three markers showed correlation with Eppendorf electrode measurements of tumor oxygenation in carcinoma of the cervix. In nine of 13 reports, among them all three that refer to curative radiotherapy for head and neck cancer, HIF-1{alpha} overexpression was associated with poor outcome. CA 9 was an adverse prognostic factor in cervix, head and neck and lung cancer, but not in two other head and neck cancer reports. GLUT1 predicted for poor survival in colorectal, cervix and lung cancer. Conclusion: Endogenous markers have the potential to indicate therapeutically relevant levels of hypoxia within tumors. Clinical trials assessing a marker's ability to predict a

  19. An insight into tumoral hypoxia: the radiomarkers and clinical applications

    Directory of Open Access Journals (Sweden)

    Ana Margarida Abrantes

    2011-12-01

    Full Text Available Tumoral hypoxia is related to severe structural abnormalities of tumor microvessels, leading to deteriorated O2 diffusion. This decreased O2 concentration in cancer cells compromises cellular functions, besides being responsible for resistance to radiation therapy. Consequently, it is very important to know the hypoxic status of a tumor. In this review, the different methodologies available for evaluating cellular hypoxia in vivo are discussed, particularly those in which the hypoxia information is obtained through imaging. Among these the nuclear medicine approach uses ligands to complex with radionuclides. The resulting radioactive complexes which may be single photon or positron emitters, are very useful as imaging probes. The nature of ligands and their corresponding complexes, with application or potential application as hypoxia detectors, will be described. A summary of the most significant results so far obtained in clinical or preclinical applications will also be discussed.

  20. Cinnamic aldehyde suppresses hypoxia-induced angiogenesis via inhibition of hypoxia-inducible factor-1α expression during tumor progression.

    Science.gov (United States)

    Bae, Woom-Yee; Choi, Jae-Sun; Kim, Ja-Eun; Jeong, Joo-Won

    2015-11-01

    During tumor progression, hypoxia-inducible factor 1 (HIF-1) plays a critical role in tumor angiogenesis and tumor growth by regulating the transcription of several genes in response to a hypoxic environment and changes in growth factors. This study was designed to investigate the effects of cinnamic aldehyde (CA) on tumor growth and angiogenesis and the mechanisms underlying CA's anti-angiogenic activities. We found that CA administration inhibits tumor growth and blocks tumor angiogenesis in BALB/c mice. In addition, CA treatment decreased HIF-1α protein expression and vascular endothelial growth factor (VEGF) expression in mouse tumors and Renca cells exposed to hypoxia in vitro. Interestingly, CA treatment did not affect the stability of von Hippel-Lindau protein (pVHL)-associated HIF-1α and CA attenuated the activation of mammalian target of rapamycin (mTOR) pathway. Collectively, these findings strongly indicate that the anti-angiogenic activity of CA is, at least in part, regulated by the mTOR pathway-mediated suppression of HIF-1α protein expression and these findings suggest that CA may be a potential drug for human cancer therapy. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Energy status parameters, hypoxia fraction and radiocurability across tumor types

    International Nuclear Information System (INIS)

    Gerweck, L.E.; Koutcher, J.; Zaidi, S.T.

    1995-01-01

    Under full nutrient in vitro conditions, the cellular adenylate energy charge of six different rodent and human tumor cell types was identical, i.e., 0.94 ± 0.01, suggesting the potential utility of this parameter as a cell (and tissue) independent marker of nutrient deprivation and hypoxia, across tumor types. The adenylate energy charge values of tumors, arising from these cells, was reduced and variable ranging from 0.72 to 0.91 for the various tumor types. However, neither the tumor adenylate energy charge, NTP/Pi, nor PCr/Pi ratios correlated with the radiobiologic hypoxic cell fractions across tumor types. The reduced adenylate energy charge in vivo suggests varying degrees of nutrient deprivation in the different tumor types, however, factors other than or in addition to hypoxia likely contribute to tumor energy status. (orig.)

  2. Relationship of hypoxia to metallothionein expression in murine tumors

    International Nuclear Information System (INIS)

    Raleigh, James A.; Chou, S.-C.; Tables, Lakesha; Suchindran, Sunil; Varia, Mahesh A.; Horsman, Michael R.

    1998-01-01

    Purpose: To investigate if metallothionein, an endogenous chemo- and radioprotectant, is expressed in hypoxic cells in mouse C3H mammary carcinomas and if that expression responds to acute changes in tumor hypoxia. Methods and Materials: C3H mammary tumors were established in the hind legs of female CDF 1 mice. The mice were then subjected to air breathing (chronic hypoxia), carbogen breathing (acute decrease in hypoxia), or hydralazine injection (acute increase in hypoxia). Ninety minutes after the start of the experiment, tumors were excised, fixed in formalin, and sectioned. Hypoxic cells and metallothionein-containing cells were quantitated by image analysis. Pimonidazole hydrochloride and an IgG 1 mouse monoclonal antibody were used to detect hypoxia, and a mouse antimetallothionein monoclonal antibody (DAKO) was used to detect Type I and II metallothionein in sets of contiguous tissue sections. Results: The distribution of immunostaining intensity for metallothionein was the same in all three groups--heavy in hypoxic cells and light in other regions of the tumors. The acute increase in hypoxia caused by hydralazine injection was accompanied by an increase in metallothionein expression (p = 0.04). Carbogen breathing largely eliminated pimonidazole binding, but metallothionein expression persisted in the tumors of carbogen-breathing mice. Conclusions: Hypoxic cells in C3H mammary carcinomas strongly express metallothionein. Metallothionein expression is responsive to acute increases in hypoxia brought about by hydralazine injection. The effectiveness of hydralazine in enhancing the activation of bioreductive cytotoxins might be offset by the increased expression of metallothionein. The persistence of metallothionein in tumors of carbogen-breathing mice might contribute to a residual radioresistance in the tumors

  3. PET-based analysis of tumor glucose metabolism and tumor hypoxia before and during anti-neoplastic treatment

    NARCIS (Netherlands)

    Bollineni, Vikram

    2015-01-01

    Tumor hypoxia is an important contributor to chemo-radiotherapy resistance. This has been demonstrated in several tumor types including non-small cell lung cancer and head and neck squamous cell carcinoma. Tumor hypoxia is a dynamic process, some parts of the tumor exhibit higher levels of hypoxia

  4. Irradiation Promotes an M2 Macrophage Phenotype in Tumor Hypoxia

    International Nuclear Information System (INIS)

    Chiang, Chi-Shiun; Fu, Sheng Yung; Wang, Shu-Chi; Yu, Ching-Fang; Chen, Fang-Hsin; Lin, Chi-Min; Hong, Ji-Hong

    2012-01-01

    Macrophages display different phenotypes with distinct functions and can rapidly respond to environmental changes. Previous studies on TRAMP-C1 tumor model have shown that irradiation has a strong impact on tumor microenvironments. The major changes include the decrease of microvascular density, the increase of avascular hypoxia, and the aggregation of tumor-associated macrophages in avascular hypoxic regions. Similar changes were observed no matter the irradiation was given to tissue bed before tumor implantation (pre-IR tumors), or to established tumors (IR tumors). Recent results on three murine tumors, TRAMP-C1 prostate adenocarcinoma, ALTS1C1 astrocytoma, and GL261 glioma, further demonstrate that different phenotypes of inflammatory cells are spatially distributed into different microenvironments in both IR and pre-IR tumors. Regions with avascular hypoxia and central necrosis have CD11b high /Gr-1+ neutrophils in the center of the necrotic area. Next to them are CD11b low /F4/80+ macrophages that sit at the junctions between central necrotic and surrounding hypoxic regions. The majority of cells in the hypoxic regions are CD11b low /CD68+ macrophages. These inflammatory cell populations express different levels of Arg I. This distribution pattern, except for neutrophils, is not observed in tumors receiving chemotherapy or an anti-angiogenesis agent which also lead to avascular hypoxia. This unique distribution pattern of inflammatory cells in IR tumor sites is interfered with by targeting the expression of a chemokine protein, SDF-1α, by tumor cells, and this also increases radiation-induced tumor growth delay. This indicates that irradiated-hypoxia tissues have distinct tumor microenvironments that favor the development of M2 macrophages and that is affected by the levels of tumor-secreted SDF-1α.

  5. Hypoxia alters the physical properties of the tumor microenvironment

    Science.gov (United States)

    Gilkes, Daniele

    Of all the deaths attributed to cancer, 90% are due to metastasis, or the spread of cancer cells from a primary tumor to distant organs, and treatments that prevent or cure metastasis remain elusive. Emerging data indicate that low oxygen states within a tumor, termed hypoxia, can alter the chemical and physical parameters of the extracellular matrix (ECM), or scaffold of the tumor tissue. These changes generate a microenvironment that may be more conducive for promoting metastasis. During tumor evolution, changes in the composition and the overall content of the ECM reflect both its biophysical and biological properties and these strongly influence the cells properties, such as cellular proliferation and cell motility. The talk will cover how hypoxia arises within normal tissue and also in tumors. We will cover the role of hypoxia in collagen biogenesis which influences compositional changes to the tumor microenvironment and discuss how these changes lead to a stiffer tumor stroma. The challenges in determining the influence of chemical versus physical cues on cancer progression will also be considered.

  6. Transcriptional response to hypoxia in human tumors.

    NARCIS (Netherlands)

    Lal, A.; Peters, H.; Croix, B. St.; Haroon, Z.A.; Dewhirst, M.W.; Strausberg, R.L.; Kaanders, J.H.A.M.; Kogel, A.J. van der; Riggins, G.J.

    2001-01-01

    BACKGROUND: The presence of hypoxic regions within solid tumors is associated with a more malignant tumor phenotype and worse prognosis. To obtain a blood supply and protect against cellular damage and death, oxygen-deprived cells in tumors alter gene expression, resulting in resistance to therapy.

  7. Hyperpolarized magnetic resonance spectroscopy for assessing tumor hypoxia.

    Science.gov (United States)

    Iversen, Ane B; Ringgaard, Steffen; Laustsen, Christoffer; Stødkilde-Jørgensen, Hans; Bentzen, Lise; Busk, Morten; Horsman, Michael R

    2015-01-01

    Hypoxic tumor cells are radioresistant, therefore, identification of hypoxia is crucial. Hyperpolarized magnetic resonance spectroscopy (HPMRS) allows real time measurements of the conversion of pyruvate to lactate, the final step of anaerobic energy production, and may thus allow non-invasive identification of hypoxia or treatment-induced changes in oxygenation. The aim of the study was to investigate the usefulness of HPMRS as a means to assess tumor hypoxia and its dynamics during intervention. C3H mammary carcinomas grown in CDF1 mice were used. To manipulate with tumor oxygenation, non-anaesthetized mice were gassed with air, 10% or 100% oxygen prior to administration of hyperpolarized [1-¹³C]pyruvate and HPMRS analysis. A direct assessment of tumor oxygen partial pressure (pO2) distributions were made using the Eppendorf oxygen electrode in a separate, but similarly treated, group of mice. Even though breathing 100% oxygen improved tumor oxygenation as evidenced by pO2 measurements, the mean (with 1 S.E.) [1-¹³C]lactate/[1-¹³C]pyruvate ratio was unaffected by this intervention, being 34 (30-37) in mice breathing air and 37 (33-42) in mice breathing 100% oxygen. In contrast, and in accordance with pO2 measurements, a significant increase in the [1-¹³C]lactate/[1-¹³C]pyruvate ratio was seen in 10% oxygen-breathing mice with a ratio of 46 (42-50). Although, no metabolic change was observed during 100% O2 breathing using HPMRS, the significant increase in the [1-¹³C]lactate/[1-¹³C]pyruvate ratio during 10% oxygen breathing suggests, that HPMRS can detect hypoxia-driven changes in the metabolic fate of pyruvate. To what extent and for what purposes HPMRS may best supplement or complement established techniques like hypoxia PET needs to be unraveled in future research.

  8. Radiation-induced nitric oxide mitigates tumor hypoxia and radioresistance in a murine SCCVII tumor model

    Energy Technology Data Exchange (ETDEWEB)

    Nagane, Masaki, E-mail: nagane@vetmed.hokudai.ac.jp [Laboratory of Radiation Biology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo (Japan); Yasui, Hironobu, E-mail: yassan@vetmed.hokudai.ac.jp [Laboratory of Radiation Biology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo (Japan); Yamamori, Tohru, E-mail: yamamorit@vetmed.hokudai.ac.jp [Laboratory of Radiation Biology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo (Japan); Zhao, Songji, E-mail: zsi@med.hokudai.ac.jp [Department of Tracer Kinetics and Bioanalysis, Graduate School of Medicine, Hokkaido University, Sapporo (Japan); Kuge, Yuji, E-mail: kuge@med.hokudai.ac.jp [Central Institute of Isotope Science, Hokkaido University, Sapporo (Japan); Tamaki, Nagara, E-mail: natamaki@med.hokudai.ac.jp [Department of Nuclear Medicine, Graduate School of Medicine, Hokkaido University, Sapporo (Japan); Kameya, Hiromi, E-mail: kameya@affrc.go.jp [Food Safety Division, National Food Research Institute, Tsukuba (Japan); Nakamura, Hideo, E-mail: naka@science-edu.org [Department of Chemistry, Hokkaido University of Education, Hakodate (Japan); Fujii, Hirotada, E-mail: hgfujii@sapmed.ac.jp [Center for Medical Education, Sapporo Medical University, Sapporo (Japan); Inanami, Osamu, E-mail: inanami@vetmed.hokudai.ac.jp [Laboratory of Radiation Biology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo (Japan)

    2013-08-02

    Highlights: •IR-induced NO increased tissue perfusion and pO{sub 2}. •IR increased NO production in tumors without changes in the mRNA and protein levels of NOS isoforms. •NOS activity assay showed that IR upregulated eNOS activity in tumors. •IR-induced NO decreased tumor hypoxia and altered tumor radiosensitivity. -- Abstract: Tumor hypoxia, which occurs mainly as a result of inadequate tissue perfusion in solid tumors, is a well-known challenge for successful radiotherapy. Recent evidence suggests that ionizing radiation (IR) upregulates nitric oxide (NO) production and that IR-induced NO has the potential to increase intratumoral circulation. However, the kinetics of NO production and the responsible isoforms for NO synthase in tumors exposed to IR remain unclear. In this study, we aimed to elucidate the mechanism by which IR stimulates NO production in tumors and the effect of IR-induced NO on tumor radiosensitivity. Hoechst33342 perfusion assay and electron spin resonance oxymetry showed that IR increased tissue perfusion and pO{sub 2} in tumor tissue. Immunohistochemical analysis using two different hypoxic probes showed that IR decreased hypoxic regions in tumors; treatment with a nitric oxide synthase (NOS) inhibitor, L-NAME, abrogated the effects of IR. Moreover, IR increased endothelial NOS (eNOS) activity without affecting its mRNA or protein expression levels in SCCVII-transplanted tumors. Tumor growth delay assay showed that L-NAME decreased the anti-tumor effect of fractionated radiation (10 Gy × 2). These results suggested that IR increased eNOS activity and subsequent tissue perfusion in tumors. Increases in intratumoral circulation simultaneously decreased tumor hypoxia. As a result, IR-induced NO increased tumor radiosensitivity. Our study provides a new insight into the NO-dependent mechanism for efficient fractionated radiotherapy.

  9. Critical Role of Aberrant Angiogenesis in the Development of Tumor Hypoxia and Associated Radioresistance

    Energy Technology Data Exchange (ETDEWEB)

    Multhoff, Gabriele, E-mail: Gabriele.multhoff@lrz.tu-muenchen.de [Department of Radiotherapy and Radiation Oncology, Klinikum rechts der Isar, Technische Universität München, Ismaninger Straße 22, 81675 Munich (Germany); Clinical Cooperation Group “Innate Immunity in Tumor Biology”, Helmholtz Zentrum München (HMGU), Ingolstädter Landstraße 1, 85764 Neuherberg (Germany); Radons, Jürgen [multimmune GmbH, Munich, Ismaningerstr. 22, 81675 Munich (Germany); Vaupel, Peter [Department of Radiotherapy and Radiation Oncology, Klinikum rechts der Isar, Technische Universität München, Ismaninger Straße 22, 81675 Munich (Germany)

    2014-04-08

    Newly formed microvessels in most solid tumors show an abnormal morphology and thus do not fulfil the metabolic demands of the growing tumor mass. Due to the chaotic and heterogeneous tumor microcirculation, a hostile tumor microenvironment develops, that is characterized inter alia by local hypoxia, which in turn can stimulate the HIF-system. The latter can lead to tumor progression and may be involved in hypoxia-mediated radioresistance of tumor cells. Herein, cellular and molecular mechanisms in tumor angiogenesis are discussed that, among others, might impact hypoxia-related radioresistance.

  10. Hypoxia-Inducible Factor Pathway Inhibition Resolves Tumor Hypoxia and Improves Local Tumor Control After Single-Dose Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Helbig, Linda [OncoRay–National Center for Radiation Research in Oncology, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden (Germany); Department of Radiation Oncology, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden (Germany); Koi, Lydia [OncoRay–National Center for Radiation Research in Oncology, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden (Germany); Department of Radiation Oncology, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden (Germany); Deutsches Konsortium für Translationale Krebsforschung, Site Dresden, Dresden (Germany); Brüchner, Kerstin [Department of Radiation Oncology, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden (Germany); Institute of Radiooncology Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Gurtner, Kristin [Department of Radiation Oncology, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden (Germany); Hess-Stumpp, Holger; Unterschemmann, Kerstin [Global Drug Discovery, Bayer Pharma, Berlin (Germany); Pruschy, Martin [Radiation Oncology, University of Zurich, Zurich (Switzerland); and others

    2014-01-01

    Purpose: To study the effects of BAY-84-7296, a novel orally bioavailable inhibitor of mitochondrial complex I and hypoxia-inducible factor 1 (HIF-1) activity, on hypoxia, microenvironment, and radiation response of tumors. Methods and Materials: UT-SCC-5 and UT-SCC-14 human squamous cell carcinomas were transplanted subcutaneously in nude mice. When tumors reached 4 mm in diameter BAY-84-7296 (Bayer Pharma AG) or carrier was daily administered to the animals. At 7 mm tumors were either excised for Western blot and immunohistologic investigations or were irradiated with single doses. After irradiation animals were randomized to receive BAY-84-7296 maintenance or carrier. Local tumor control was evaluated 150 days after irradiation, and the dose to control 50% of tumors (TCD{sub 50}) was calculated. Results: BAY-84-7296 decreased nuclear HIF-1α expression. Daily administration of inhibitor for approximately 2 weeks resulted in a marked decrease of pimonidazole hypoxic fraction in UT-SCC-5 (0.5% vs 21%, P<.0001) and in UT-SCC-14 (0.3% vs 19%, P<.0001). This decrease was accompanied by a significant increase in fraction of perfused vessels in UT-SCC-14 but not in UT-SCC-5. Bromodeoxyuridine and Ki67 labeling indices were significantly reduced only in UT-SCC-5. No significant changes were observed in vascular area or necrosis. BAY-84-7296 before single-dose irradiation significantly decreased TCD{sub 50}, with an enhancement ratio of 1.37 (95% confidence interval [CI] 1.13-1.72) in UT-SCC-5 and of 1.55 (95% CI 1.26-1.94) in UT-SCC-14. BAY-84-7296 maintenance after irradiation did not further decrease TCD{sub 50}. Conclusions: BAY-84-7296 resulted in a marked decrease in tumor hypoxia and substantially reduced radioresistance of tumor cells with the capacity to cause a local recurrence after irradiation. The data suggest that reduction of cellular hypoxia tolerance by BAY-84-7296 may represent the primary biological mechanism underlying the observed enhancement of

  11. Assessment of Hypoxia in the Stroma of Patient-Derived Pancreatic Tumor Xenografts

    Energy Technology Data Exchange (ETDEWEB)

    Lohse, Ines; Lourenco, Corey; Ibrahimov, Emin; Pintilie, Melania [Ontario Cancer Institute and Campbell Family Cancer Research Institute, Princess Margaret Cancer Center, University Health Network, 610 University Ave., Toronto, ON M5G2M9 (Canada); Tsao, Ming-Sound [Ontario Cancer Institute and Campbell Family Cancer Research Institute, Princess Margaret Cancer Center, University Health Network, 610 University Ave., Toronto, ON M5G2M9 (Canada); Department of Pathology, University Health Network, 200 Elizabeth Street, Toronto, ON M5G2C4 (Canada); Department of Laboratory Medicine and Pathobiology, 27 King’s College Circle, University of Toronto, Toronto, ON M5S1A1 (Canada); Hedley, David W., E-mail: david.hedley@uhn.ca [Ontario Cancer Institute and Campbell Family Cancer Research Institute, Princess Margaret Cancer Center, University Health Network, 610 University Ave., Toronto, ON M5G2M9 (Canada); Departments of Medical Biophysics University of Toronto, 610 University Ave., Toronto, ON M5G2M9 (Canada); Departments of Medicine, University of Toronto, 610 University Ave., Toronto, ON M5G2M9 (Canada); Department of Medical Oncology and Hematology, Princess Margaret Cancer Center, 610 University Ave., Toronto, ON M5G2M9 (Canada)

    2014-02-26

    The unusually dense stroma of pancreatic cancers is thought to play an important role in their biological aggression. The presence of hypoxia is also considered an adverse prognostic factor. Although it is usually assumed that this is the result of effects of hypoxia on the epithelial component, it is possible that hypoxia exerts indirect effects via the tumor stroma. We therefore measured hypoxia in the stroma of a series of primary pancreatic cancer xenografts. Nine patient-derived pancreatic xenografts representing a range of oxygenation levels were labeled by immunohistochemistry for EF5 and analyzed using semi-automated pattern recognition software. Hypoxia in the tumor and stroma was correlated with tumor growth and metastatic potential. The extent of hypoxia varied from 1%–39% between the different models. EF5 labeling in the stroma ranged from 0–20% between models, and was correlated with the level of hypoxia in the tumor cell area, but not microvessel density. Tumor hypoxia correlated with spontaneous metastasis formation with the exception of one hypoxic model that showed disproportionately low levels of hypoxia in the stroma and was non-metastatic. Our results demonstrate that hypoxia exists in the stroma of primary pancreatic cancer xenografts and suggest that stromal hypoxia impacts the metastatic potential.

  12. A preclinical model for noninvasive imaging of hypoxia-induced gene expression; comparison with an exogenous marker of tumor hypoxia

    International Nuclear Information System (INIS)

    Wen Bixiu; Burgman, Paul; Zanzonico, Pat; O'Donoghue, Joseph; Li, Gloria C.; Ling, C. Clifton; Cai Shangde; Finn, Ron; Serganova, Inna; Blasberg, Ronald; Gelovani, Juri

    2004-01-01

    Hypoxia is associated with tumor aggressiveness and is an important cause of resistance to radiation therapy and chemotherapy. Assays of tumor hypoxia could provide selection tools for hypoxia-modifying treatments. The purpose of this study was to develop and characterize a rodent tumor model with a reporter gene construct that would be transactivated by the hypoxia-inducible molecular switch, i.e., the upregulation of HIF-1. The reporter gene construct is the herpes simplex virus 1-thymidine kinase (HSV1-tk) fused with the enhanced green fluorescent protein (eGFP) under the regulation of an artificial hypoxia-responsive enhancer/promoter. In this model, tumor hypoxia would up-regulate HIF-1, and through the hypoxia-responsive promoter transactivate the HSV1-tkeGFPfusion gene. The expression of this reporter gene can be assessed with the 124 I-labeled reporter substrate 2'-fluoro-2'-deoxy-1-β-d-arabinofuranosyl-5-iodouracil ( 124 I-FIAU), which is phosphorylated by the HSV1-tk enzyme and trapped in the hypoxic cells. Animal positron emission tomography (microPET) and phosphor plate imaging (PPI) were used in this study to visualize the trapped 124 I-FIAU, providing a distribution of the hypoxia-induced molecular events. The distribution of 124 I-FIAU was also compared with that of an exogenous hypoxic cell marker, 18 F-fluoromisonidazole (FMISO). Our results showed that 124 I-FIAU microPET imaging of the hypoxia-induced reporter gene expression is feasible, and that the intratumoral distributions of 124 I-FIAU and 18 F-FMISO are similar. In tumor sections, detailed radioactivity distributions were obtained with PPI which also showed similarity between 124 I-FIAU and 18 F-FMISO. This reporter system is sufficiently sensitive to detect hypoxia-induced transcriptional activation by noninvasive imaging and might provide a valuable tool in studying tumor hypoxia and in validating existing and future exogenous markers for tumor hypoxia. (orig.)

  13. Hypoxia in tumors: pathogenesis-related classification, characterization of hypoxia subtypes, and associated biological and clinical implications.

    Science.gov (United States)

    Vaupel, Peter; Mayer, Arnulf

    2014-01-01

    Hypoxia is a hallmark of tumors leading to (mal-)adaptive processes, development of aggressive phenotypes and treatment resistance. Based on underlying mechanisms and their duration, two main types of hypoxia have been identified, coexisting with complex spatial and temporal heterogeneities. Chronic hypoxia is mainly caused by diffusion limitations due to enlarged diffusion distances and adverse diffusion geometries (e.g., concurrent vs. countercurrent microvessels, Krogh- vs. Hill-type diffusion geometry) and, to a lesser extent, by hypoxemia (e.g., in anemic patients, HbCO formation in heavy smokers), and a compromised perfusion or flow stop (e.g., due to disturbed Starling forces or intratumor solid stress). Acute hypoxia mainly results from transient disruptions in perfusion (e.g., vascular occlusion by cell aggregates), fluctuating red blood cell fluxes or short-term contractions of the interstitial matrix. In each of these hypoxia subtypes oxygen supply is critically reduced, but perfusion-dependent nutrient supply, waste removal, delivery of anticancer or diagnostic agents, and repair competence can be impaired or may not be affected. This detailed differentiation of tumor hypoxia may impact on our understanding of tumor biology and may aid in the development of novel treatment strategies, tumor detection by imaging and tumor targeting, and is thus of great clinical relevance.

  14. Long-term exposure to hypoxia inhibits tumor progression of lung cancer in rats and mice

    International Nuclear Information System (INIS)

    Yu, Lunyin; Hales, Charles A

    2011-01-01

    Hypoxia has been identified as a major negative factor for tumor progression in clinical observations and in animal studies. However, the precise role of hypoxia in tumor progression has not been fully explained. In this study, we extensively investigated the effect of long-term exposure to hypoxia on tumor progression in vivo. Rats bearing transplanted tumors consisting of A549 human lung cancer cells (lung cancer tumor) were exposed to hypoxia for different durations and different levels of oxygen. The tumor growth and metastasis were evaluated. We also treated A549 lung cancer cells (A549 cells) with chronic hypoxia and then implanted the hypoxia-pretreated cancer cells into mice. The effect of exposure to hypoxia on metastasis of Lewis lung carcinoma in mice was also investigated. We found that long-term exposure to hypoxia a) significantly inhibited lung cancer tumor growth in xenograft and orthotopic models in rats, b) significantly reduced lymphatic metastasis of the lung cancer in rats and decreased lung metastasis of Lewis lung carcinoma in mice, c) reduced lung cancer cell proliferation and cell cycle progression in vitro, d) decreased growth of the tumors from hypoxia-pretreated A549 cells, e) decreased Na + -K + ATPase α1 expression in hypoxic lung cancer tumors, and f) increased expression of hypoxia inducible factors (HIF1α and HIF2α) but decreased microvessel density in the lung cancer tumors. In contrast to lung cancer, the growth of tumor from HCT116 human colon cancer cells (colon cancer tumor) was a) significantly enhanced in the same hypoxia conditions, accompanied by b) no significant change in expression of Na + -K + ATPase α1, c) increased HIF1α expression (no HIF2α was detected) and d) increased microvessel density in the tumor tissues. This study demonstrated that long-term exposure to hypoxia repressed tumor progression of the lung cancer from A549 cells and that decreased expression of Na + -K + ATPase was involved in hypoxic

  15. Pyruvate induces transient tumor hypoxia by enhancing mitochondrial oxygen consumption and potentiates the anti-tumor effect of a hypoxia-activated prodrug TH-302.

    Directory of Open Access Journals (Sweden)

    Yoichi Takakusagi

    Full Text Available BACKGROUND: TH-302 is a hypoxia-activated prodrug (HAP of bromo isophosphoramide mustard that is selectively activated within hypoxic regions in solid tumors. Our recent study showed that intravenously administered bolus pyruvate can transiently induce hypoxia in tumors. We investigated the mechanism underlying the induction of transient hypoxia and the combination use of pyruvate to potentiate the anti-tumor effect of TH-302. METHODOLOGY/RESULTS: The hypoxia-dependent cytotoxicity of TH-302 was evaluated by a viability assay in murine SCCVII and human HT29 cells. Modulation in cellular oxygen consumption and in vivo tumor oxygenation by the pyruvate treatment was monitored by extracellular flux analysis and electron paramagnetic resonance (EPR oxygen imaging, respectively. The enhancement of the anti-tumor effect of TH-302 by pyruvate treatment was evaluated by monitoring the growth suppression of the tumor xenografts inoculated subcutaneously in mice. TH-302 preferentially inhibited the growth of both SCCVII and HT29 cells under hypoxic conditions (0.1% O2, with minimal effect under aerobic conditions (21% O2. Basal oxygen consumption rates increased after the pyruvate treatment in SCCVII cells in a concentration-dependent manner, suggesting that pyruvate enhances the mitochondrial respiration to consume excess cellular oxygen. In vivo EPR oxygen imaging showed that the intravenous administration of pyruvate globally induced the transient hypoxia 30 min after the injection in SCCVII and HT29 tumors at the size of 500-1500 mm(3. Pretreatment of SCCVII tumor bearing mice with pyruvate 30 min prior to TH-302 administration, initiated with small tumors (∼ 550 mm(3, significantly delayed tumor growth. CONCLUSIONS/SIGNIFICANCE: Our in vitro and in vivo studies showed that pyruvate induces transient hypoxia by enhancing mitochondrial oxygen consumption in tumor cells. TH-302 therapy can be potentiated by pyruvate pretreatment if started at the

  16. Overexpression of Dimethylarginine Dimethylaminohydrolase Enhances Tumor Hypoxia: An Insight into the Relationship of Hypoxia and Angiogenesis In Vivo

    Directory of Open Access Journals (Sweden)

    Vassiliki Kostourou

    2004-07-01

    Full Text Available The oxygenation status of tumors derived from wild-type C6 glioma cells and clone D27 cells overexpressing dimethylarginine dimethylaminohydrolase (DDAH was assessed in vivo using a variety of direct and indirect assays of hypoxia. Clone D27 tumors exhibit a more aggressive and better-vascularized phenotype compared to wild-type C6 gliomas. Immunohistochemical analyses using the 2-nitroimidazole hypoxia marker pimonidazole, fiber optic OxyLite measurements of tumor pO2, and localized 31P magnetic resonance spectroscopy measurements of tumor bioenergetic status and pH clearly demonstrated that the D27 tumors were more hypoxic compared to C6 wild type. In the tumor extracts, only glucose concentrations were significantly lower in the D27 tumors. Elevated Glut-1 expression, a reliable functional marker for hypoxia-inducible factor-1-mediated metabolic adaptation, was observed in the D27 tumors. Together, the data show that overexpression of DDAH results in C6 gliomas that are more hypoxic compared to wild-type tumors, and point strongly to an inverse relationship of tumor oxygenation and angiogenesis in vivo-a concept now being supported by the enhanced understanding of oxygen sensing at the molecular level.

  17. Hypoxia Induced Tumor Metabolic Switch Contributes to Pancreatic Cancer Aggressiveness

    Energy Technology Data Exchange (ETDEWEB)

    Vasseur, Sophie, E-mail: sophie.vasseur@inserm.fr; Tomasini, Richard; Tournaire, Roselyne; Iovanna, Juan L. [INSERM U624, Stress Cellulaire, Parc Scientifique et Technologique de Luminy, 163 Avenue de Luminy, BP 915,13288 Marseille cedex 9 (France)

    2010-12-16

    Pancreatic ductal adenocarcinoma remains one of the most lethal of all solid tumors with an overall five-year survival rate of only 3–5%. Its aggressive biology and resistance to conventional and targeted therapeutic agents lead to a typical clinical presentation of incurable disease once diagnosed. The disease is characterized by the presence of a dense stroma of fibroblasts and inflammatory cells, termed desmoplasia, which limits the oxygen diffusion in the organ, creating a strong hypoxic environment within the tumor. In this review, we argue that hypoxia is responsible for the highly aggressive and metastatic characteristics of this tumor and drives pancreatic cancer cells to oncogenic and metabolic changes facilitating their proliferation. However, the molecular changes leading to metabolic adaptations of pancreatic cancer cells remain unclear. Cachexia is a hallmark of this disease and illustrates that this cancer is a real metabolic disease. Hence, this tumor must harbor metabolic pathways which are probably tied in a complex inter-organ dialog during the development of this cancer. Such a hypothesis would better explain how under fuel source limitation, pancreatic cancer cells are maintained, show a growth advantage, and develop metastasis.

  18. Hypoxia Induced Tumor Metabolic Switch Contributes to Pancreatic Cancer Aggressiveness

    Directory of Open Access Journals (Sweden)

    Juan L. Iovanna

    2010-12-01

    Full Text Available Pancreatic ductal adenocarcinoma remains one of the most lethal of all solid tumors with an overall five-year survival rate of only 3–5%. Its aggressive biology and resistance to conventional and targeted therapeutic agents lead to a typical clinical presentation of incurable disease once diagnosed. The disease is characterized by the presence of a dense stroma of fibroblasts and inflammatory cells, termed desmoplasia, which limits the oxygen diffusion in the organ, creating a strong hypoxic environment within the tumor. In this review, we argue that hypoxia is responsible for the highly aggressive and metastatic characteristics of this tumor and drives pancreatic cancer cells to oncogenic and metabolic changes facilitating their proliferation. However, the molecular changes leading to metabolic adaptations of pancreatic cancer cells remain unclear. Cachexia is a hallmark of this disease and illustrates that this cancer is a real metabolic disease. Hence, this tumor must harbor metabolic pathways which are probably tied in a complex inter-organ dialog during the development of this cancer. Such a hypothesis would better explain how under fuel source limitation, pancreatic cancer cells are maintained, show a growth advantage, and develop metastasis.

  19. The Role of Hypoxia in the Tumor Microenvironment: Implications for Ovarian Cancer Therapy

    Science.gov (United States)

    2017-07-01

    kit (Rankin et al., 2012). Tumor sections will be stained and quantified for CD31, an endothelial cell marker . The number of CD31 positive vessels...AWARD NUMBER: W81XWH-15-1-0097 TITLE: The Role of Hypoxia in the Tumor Microenvironment: Implications for Ovarian Cancer Therapy PRINCIPAL...SUBTITLE 5a. CONTRACT NUMBER 0097W81XW 0097The Role of Hypoxia in the Tumor Microenvironment: Implications for Ovarian Cancer Therapy

  20. δ-Tocotrienol Oxazine Derivative Antagonizes Mammary Tumor Cell Compensatory Response to CoCl2-Induced Hypoxia

    Directory of Open Access Journals (Sweden)

    Suryatheja Ananthula

    2014-01-01

    Full Text Available In response to low oxygen supply, cancer cells elevate production of HIF-1α, a hypoxia-inducible transcription factor that subsequently acts to stimulate blood vessel formation and promote survival. Studies were conducted to determine the role of δ-tocotrienol and a semisynthetic δ-tocotrienol oxazine derivative, compound 44, on +SA mammary tumor cell hypoxic response. Treatment with 150 µM CoCl2 induced a hypoxic response in +SA mammary tumor cells as evidenced by a large increase in HIF-1α levels, and combined treatment with compound 44 attenuated this response. CoCl2-induced hypoxia was also associated with a large increase in Akt/mTOR signaling, activation of downstream targets p70S6K and eIF-4E1, and a significant increase in VEGF production, and combined treatment with compound 44 blocked this response. Additional in vivo studies showed that intralesional treatment with compound 44 in BALB/c mice bearing +SA mammary tumors significantly decreased the levels of HIF-1α, and this effect was associated with a corresponding decrease in Akt/mTOR signaling and activation of downstream targets p70S6kinase and eIF-4E1. These findings demonstrate that treatment with the δ-tocotrienol oxazine derivative, compound 44, significantly attenuates +SA mammary tumor cell compensatory responses to hypoxia and suggests that this compound may provide benefit in the treatment of rapidly growing solid breast tumors.

  1. Intersection of interferon and hypoxia signal transduction pathways in nitric oxide-induced tumor apoptosis.

    Science.gov (United States)

    Tendler, D S; Bao, C; Wang, T; Huang, E L; Ratovitski, E A; Pardoll, D A; Lowenstein, C J

    2001-05-01

    Activated macrophages play a central role in antitumor immunity. However, the stimuli that activate macrophages to kill tumor cells are not completely understood. Because the center of solid tumors can be hypoxic, we hypothesized that hypoxia may be an important signal in activating macrophages to kill tumor cells. Hypoxia stimulates IFN-primed macrophages to express the inducible nitric oxide synthase (NOS2) and to synthesize nitric oxide (NO). We show that this synergy between IFN and hypoxia is mediated by the direct interaction of the hypoxia inducible factor-1 (HIF-1) and IFN regulatory factor-1 (IRF-1), which are both required for the hypoxic transcription of NOS2. This interaction between HIF-1 and IRF-1 may explain the mechanism by which macrophages infiltrating into tumors are activated to express NOS2 and to produce NO, a mediator of tumor apoptosis.

  2. Hypoxia-Inducible Regulation of a Prodrug-Activating Enzyme for Tumor-Specific Gene Therapy

    Directory of Open Access Journals (Sweden)

    Toru Shibata

    2002-01-01

    Full Text Available Previous studies have suggested that tumor hypoxia could be exploited for cancer gene therapy. Using hypoxia-responsive elements derived from the human vascular endothelial growth factor gene, we have generated vectors expressing a bacterial nitroreductase. (20NTR gene that can activate the anticancer prodrug CB1954. Stable transfectants of human HT1080 tumor cells with hypoxia-inducible vectors were established with G418 selection. Hypoxic induction of NTR protein correlated with increased sensitivity to in vitro exposure of HT 1080 cells to the prodrug. Growth delay assays were performed with established tumor xenografts derived from the same cells to detect the in vivo efficacy of CB1954 conversion to its cytotoxic form. Significant antitumor effects were achieved with intraperitoneal injections of CB1954 both in tumors that express NTR constitutively or with a hypoxia-inducible promoter. In addition, respiration of 10% O2 increased tumor hypoxia in vivo and enhanced the antitumor effects. Taken together, these results demonstrate that hypoxia-inducible vectors may be useful for tumor-selective gene therapy, although the problem of delivery of the vector to the tumors, particularly to the hypoxic cells in the tumors, is not addressed by these studies.

  3. Hypoxia downregulates Ku70/80 expression in cervical carcinoma tumors

    International Nuclear Information System (INIS)

    Lara, Pedro Carlos; Lloret, Marta; Clavo, Bernardino; Apolinario, Rosa Maria; Bordon, Elisa; Rey, Agustin; Falcon, Orlando; Alonso, Ana Ruiz; Belka, Claus

    2008-01-01

    Hypoxia may inhibits the NHEJ DNA repair through downregulating Ku70/80 expression and combined with an increased angiogenesis and altered p53 expression would be responsible for tumor progression in cervical carcinoma

  4. Effect of a topical vasodilator on tumor hypoxia and tumor oxygen guided radiotherapy using EPR oximetry.

    Science.gov (United States)

    Hou, Huagang; Abramovic, Zrinka; Lariviere, Jean P; Sentjurc, Marjeta; Swartz, Harold; Khan, Nadeem

    2010-05-01

    We sought to reduce tumor hypoxia by topical application of a vasodilator, benzyl nicotinate (BN), and investigated its effect on the growth of tumors irradiated at times when tumor pO(2) increased. EPR oximetry was used to follow the changes in the tissue pO(2) of subcutaneous radiation-induced fibrosarcoma (RIF-1) tumors during topical applications of 1.25-8% BN formulations for 5 consecutive days. The RIF-1 tumors were hypoxic with a tissue pO(2) of 4.6-7.0 mmHg. A significant increase in tumor pO(2) occurred 10-30 min after BN application. The formulation with the minimal BN concentration that produced a significant increase in tumor pO(2) was used for the radiation study. The tumors were irradiated (4 Gy x 5) at the time of the maximum increase in pO(2) observed with the 2.5% BN formulation. The tumors with an increase in pO(2) of greater than 2 mmHg from the baseline after application of BN on day 1 had a significant growth inhibition compared to the tumors with an increase in pO(2) of less than 2 mmHg. The results indicate that the irradiation of tumors at the time of an increase in pO(2) after the topical application of the 2.5% BN formulation led to a significant growth inhibition. EPR oximetry provided dynamic information on the changes in tumor pO(2), which could be used to identify responders and non-responders and schedule therapy during the experiments.

  5. Hypofractionation results in reduced tumor cell kill compared to conventional fractionation for tumors with regions of hypoxia.

    Science.gov (United States)

    Carlson, David J; Keall, Paul J; Loo, Billy W; Chen, Zhe J; Brown, J Martin

    2011-03-15

    Tumor hypoxia has been observed in many human cancers and is associated with treatment failure in radiation therapy. The purpose of this study is to quantify the effect of different radiation fractionation schemes on tumor cell killing, assuming a realistic distribution of tumor oxygenation. A probability density function for the partial pressure of oxygen in a tumor cell population is quantified as a function of radial distance from the capillary wall. Corresponding hypoxia reduction factors for cell killing are determined. The surviving fraction of a tumor consisting of maximally resistant cells, cells at intermediate levels of hypoxia, and normoxic cells is calculated as a function of dose per fraction for an equivalent tumor biological effective dose under normoxic conditions. Increasing hypoxia as a function of distance from blood vessels results in a decrease in tumor cell killing for a typical radiotherapy fractionation scheme by a factor of 10(5) over a distance of 130 μm. For head-and-neck cancer and prostate cancer, the fraction of tumor clonogens killed over a full treatment course decreases by up to a factor of ∼10(3) as the dose per fraction is increased from 2 to 24 Gy and from 2 to 18 Gy, respectively. Hypofractionation of a radiotherapy regimen can result in a significant decrease in tumor cell killing compared to standard fractionation as a result of tumor hypoxia. There is a potential for large errors when calculating alternate fractionations using formalisms that do not account for tumor hypoxia. Copyright © 2011 Elsevier Inc. All rights reserved.

  6. Relations between radiobiological hypoxia and nuclear magnetic resonance-imaged blood microcirculation in experimental tumors

    International Nuclear Information System (INIS)

    Koike, Sachiko; Ando, Koichi; Ikehira, Hiroo.

    1993-01-01

    Characteristics of hypoxic cells subjected to radiation were investigated and compared with those of microcirculation for two murine fibrosarcomas growing in C3H mice. Small NFSa tumors, growing in air-breathing mice, developed a radioresistant tail on the survival curve. The tail was indistinguishably parallel to a survival curve for an artificially hypoxic tumor. As the NFSa tumors increased in size, the hypoxic tail moved upward with no change of Do, resulting in increase of hypoxic fraction from 3.9% to 40%. The R1137 tumors had no radioresistant tail nor hypoxic fraction regardless of tumor size. However, large-sized R1137 tumors developed a significant number of radioresistant, hypoxic cells with an intermediate Do, and were effectively sensitized by administrating misonidazole before irradiation. Thus, the NFSa tumors were fractionally hypoxic, and the large R1137 tumors had intermediate hypoxia. Measurement of tumor microcirculation by gadolinium-enhanced nuclear magnetic resonance indicated that both blood flow and blood volume decreased significantly when the NFSa tumor grew large. Similar reduction in these microcirculation parameters was also observed for the R1137 tumor. The small-sized NFSa tumor had relatively larger blood volume and faster blood flow than the small-sized R1137 tumor. When large-sized tumors were compared to each other, the NFSa again had better blood flow than the R1137. However, the blood volume in the large-sized tumors was significantly (p<0.05) smaller for the NFSa tumor than for the R1137 tumor. It was concluded that blood flow could not be a single determinant for tumor hypoxia, and the difference between fractional hypoxia and intermediate hypoxia would be reflected in the ratio of blood flow to blood volume. (author)

  7. Changes in tumor hypoxia induced by mild temperature hyperthermia as assessed by dual-tracer immunohistochemistry

    International Nuclear Information System (INIS)

    Sun Xiaorong; Li Xiaofeng; Russell, James; Xing Ligang; Urano, Muneyasu; Li, Gloria C.; Humm, John L.; Ling, C. Clifton

    2008-01-01

    Purpose: To study the changes in hypoxia resulting from mild temperature hyperthermia (MTH) in a subcutaneous xenograft model using dual-tracer immunohistochemical techniques. Materials and methods: HT29 tumors were locally heated at 41 o C. Changes in tumor hypoxia were investigated by pimonidazole and EF5. Pimonidazole was given 1 h preheating, EF5 at various times during or after treatment, 1 h later the animals were sacrificed. Blood vessels were identified by CD31 staining, and perfusion by Hoechst 33342 injected 1 min pre-sacrifice. Results: The overall hypoxic fraction was significantly decreased by MTH during and immediately after heating. However, MTH induced both increases and decreases in tumor hypoxia in different parts of the tumor. Specifically, MTH decreased hypoxia in the regions with relatively well-perfused blood vessels, but increased hypoxia in regions that were poorly perfused. At 24-h post heating, newly formed hypoxic regions surrounded previously-hypoxic foci, which in turn surrounded pimonidazole-stained debris. Quantitative analysis did not evince changes in tumor oxygenation due to MTH at 24 h post-treatment. Conclusion: In this xenograft model, the effect of MTH on tumor oxygenation was variable, both spatially and kinetically. Overall tumor oxygenation was improved during and after heating, but the effect was short-lived

  8. Tumor hypoxia - A confounding or exploitable factor in interstitial brachytherapy? Effects of tissue trauma in an experimental rat tumor model

    NARCIS (Netherlands)

    van den Berg, AP; van Geel, CAJF; van Hooije, CMC; van der Kleij, AJ; Visser, AG

    2000-01-01

    Purpose: To evaluate the potential effects of tumor hypoxia induced by afterloading catheter implantation on the effectiveness of brachytherapy in a rat tumor model. Methods and Materials: Afterloading catheters (4) Here implanted in subcutaneously growing R1M rhabdomyosarcoma in female Wag/Rij

  9. Monitoring and Targeting Anti-VEGF Induced Hypoxia within the Viable Tumor by 19F–MRI and Multispectral Analysis

    Directory of Open Access Journals (Sweden)

    Yunzhou Shi

    2017-11-01

    Full Text Available The effect of anti-angiogenic agents on tumor oxygenation has been in question for a number of years, where both increases and decreases in tumor pO2 have been observed. This dichotomy in results may be explained by the role of vessel normalization in the response of tumors to anti-angiogenic therapy, where anti-angiogenic therapies may initially improve both the structure and the function of tumor vessels, but more sustained or potent anti-angiogenic treatments will produce an anti-vascular response, producing a more hypoxic environment. The first goal of this study was to employ multispectral (MS 19F–MRI to noninvasively quantify viable tumor pO2 and evaluate the ability of a high dose of an antibody to vascular endothelial growth factor (VEGF to produce a strong and prolonged anti-vascular response that results in significant tumor hypoxia. The second goal of this study was to target the anti-VEGF induced hypoxic tumor micro-environment with an agent, tirapazamine (TPZ, which has been designed to target hypoxic regions of tumors. These goals have been successfully met, where an antibody that blocks both murine and human VEGF-A (B20.4.1.1 was found by MS 19F–MRI to produce a strong anti-vascular response and reduce viable tumor pO2 in an HM-7 xenograft model. TPZ was then employed to target the anti-VEGF-induced hypoxic region. The combination of anti-VEGF and TPZ strongly suppressed HM-7 tumor growth and was superior to control and both monotherapies. This study provides evidence that clinical trials combining anti-vascular agents with hypoxia-activated prodrugs should be considered to improved efficacy in cancer patients.

  10. Head and neck tumor hypoxia imaging by 18F-fluoroazomycin-arabinoside (18F-FAZA)-PET : a review

    NARCIS (Netherlands)

    Halmos, Gyorgy B.; de Bruin, Leonie Bruine; Langendijk, Johannes A.; van der Laan, Bernard F. A. M.; Pruim, Jan; Steenbakkers, Roel J. H. M.

    Tumor hypoxia is known to be associated with poor clinical outcome; therefore, patients with hypoxic tumors might benefit from more intensive treatment approaches. This is particularly true for patients with head and neck cancer. Pretreatment assessment of hypoxia in tumors would be desirable, not

  11. Severe hypoxia induces chemo-resistance in clinical cervical tumors through MVP over-expression

    Directory of Open Access Journals (Sweden)

    Apolinario Rosa M

    2009-08-01

    Full Text Available Abstract Oxygen molecule modulates tumour response to radiotherapy. Higher radiation doses are required under hypoxic conditions to induce cell death. Hypoxia may inhibit the non-homologous end-joining DNA repair through down regulating Ku70/80 expression. Hypoxia induces drug resistance in clinical tumours, although the mechanism is not clearly elucidated. Vaults are ribonucleoprotein particles with a hollow barrel-like structure composed of three proteins: major vault protein (MVP, vault poly(ADP-ribose polymerase, and telomerase associated protein-1 and small untranslated RNA. Over-expression of MVP has been associated with chemotherapy resistance. Also, it has been related to poor outcome in patients treated with radiotherapy alone. The aim of the present study was to assess the relation of Major Vault Protein expression and tumor hypoxia in clinical cervical tumors. MVP, p53 and angiogenesis, together with tumor oxygenation, were determined in forty-three consecutive patients suffering from localized cervix carcinoma. High MVP expression was related to severe hypoxia compared to low MVP expressing tumors (p = 0.022. Tumors over-expressing MVP also showed increased angiogenesis (p = 0.003. Besides it, in this study we show for the first time that severe tumor hypoxia is associated with high MVP expression in clinical cervical tumors. Up-regulation of MVP by hypoxia is of critical relevance as chemotherapy is currently a standard treatment for those patients. From our results it could be suggested that hypoxia not only induces increased genetic instability, oncogenic properties and metastatization, but through the correlation observed with MVP expression, another pathway of chemo and radiation resistance could be developed.

  12. Kalkitoxin Inhibits Angiogenesis, Disrupts Cellular Hypoxic Signaling, and Blocks Mitochondrial Electron Transport in Tumor Cells

    Directory of Open Access Journals (Sweden)

    J. Brian Morgan

    2015-03-01

    Full Text Available The biologically active lipopeptide kalkitoxin was previously isolated from the marine cyanobacterium Moorea producens (Lyngbya majuscula. Kalkitoxin exhibited N-methyl-d-aspartate (NMDA-mediated neurotoxicity and acted as an inhibitory ligand for voltage-sensitive sodium channels in cultured rat cerebellar granule neurons. Subsequent studies revealed that kalkitoxin generated a delayed form of colon tumor cell cytotoxicity in 7-day clonogenic cell survival assays. Cell line- and exposure time-dependent cytostatic/cytotoxic effects were previously observed with mitochondria-targeted inhibitors of hypoxia-inducible factor-1 (HIF-1. The transcription factor HIF-1 functions as a key regulator of oxygen homeostasis. Therefore, we investigated the ability of kalkitoxin to inhibit hypoxic signaling in human tumor cell lines. Kalkitoxin potently and selectively inhibited hypoxia-induced activation of HIF-1 in T47D breast tumor cells (IC50 5.6 nM. Mechanistic studies revealed that kalkitoxin inhibits HIF-1 activation by suppressing mitochondrial oxygen consumption at electron transport chain (ETC complex I (NADH-ubiquinone oxidoreductase. Further studies indicate that kalkitoxin targets tumor angiogenesis by blocking the induction of angiogenic factors (i.e., VEGF in tumor cells.

  13. Efficacy and biological effects of techniques used to induce hypoxia in tumors

    International Nuclear Information System (INIS)

    Rockwell, S.; Moulder, J.E.; Martin, D.F.

    1985-01-01

    The authors tested several aspects of the assumptions using BA1112 rat rhabdomyosacromas and EMT6 mouse mammary tumors. Both techniques were effective in producing hypoxia: survival curves for tumors made hypoxic by the 2 techniques were the same, and were indistinguishable from survival curves for hypoxic tumor cells in vitro. Induction of hypoxia for the 30-60 min necessary for irradiation did not alter the yield or clonogenicity of cells suspended from the tumors. Longer clamping was cytotoxic. Clamping did not alter tumor growth unless a major blood vessel was injured. However, clamping BA1112 tumors for 30 min and removing the clamp just before irradiation altered the tumor cell survival curve and TCD/sub 50/. Anesthesia or restrain, often used during clamping, can have major effects

  14. Monitoring of cycling hypoxia and angiogenesis in FaDu head and neck tumors using a side-firing sensor

    Science.gov (United States)

    Yu, Bing; Shah, Amy; Wang, Bingqing; Rajaram, Narasimhan; Wang, Quanli; Ramanujam, Nirmala; Palmer, Gregory M.; Dewhirst, Mark W.

    2013-03-01

    Many studies have found that hypoxia, particularly cycling hypoxia (CH), can lead to enhanced tumor metastasis and resistance to radiation and chemotherapy. It was also reported that tumor total hemoglobin content (THb), which is directly related to tumor angiogenesis, can have significant impact on tumor's response to radiation and neoadjuvant chemotherapy. There is a growing demand for technologies to measure tumor hypoxia and angiogenesis temporally in vivo. In this paper, a side-firing fiber optic sensor based on a multi-wavelength frequency-domain near infrared spectroscopy (FD-NIRS) instrument was used to quantify tumor oxygenation and hemoglobin concentrations in nude rats bearing human FaDu head and neck (H and N) tumors during normoxia and forced hyperoxia and cyclic hypoxia. Significant increase (with carbogen gas inhalation) or decrease (with reduced O2 supply) in tumor oxygenation was observed. The studies demonstrated the feasibility of the technology for longitudinal monitoring of H and N tumor's response to therapy.

  15. Hypoxia targeting therapy with prodrug specifically stabilized and activated in hypoxic tumor cells

    International Nuclear Information System (INIS)

    Kondoh, S.K.; Ueda, T.; Harada, H.; Hiraoka, M.; Akagi, K.

    2003-01-01

    Hypoxia fraction in tumors is associated with increased metastasis and poor survival in patients suffering from malignant tumors such as the head and neck, cervical or breast cancers. Hypoxia can be a direct cause of therapeutic resistance because some drugs and radiation require oxygen to be maximally cytotoxic. Recently we have reported a novel hypoxia targeting prodrug, TOP3, which is a fusion protein, composed of HIV TAT protein transduction domain, a part of HIF1 α ODD domain, and Procaspase-3. TOP3 can be transferred into every cell both in vitro and in vivo but becomes stable only in hypoxic cells, in which TOP3 is activated and induces apoptosis. The application of this fusion protein to a tumor-bearing mouse resulted in significant suppression of the tumor growth and even in reduction of the tumor mass without any obvious side effects. The administrations of TOP3 in combination with a low dose of X-ray showed an additive antitumor effect on pancreatic tumor cells. Furthermore, we show that the rodent model of ascites generated by malignant cells provides an excellent platform of testing hypoxia targeting drugs, since it comprises homogeneous fluid with tumor cells surviving and proliferating under hypoxic condition. TOP3 induced apoptosis of AH130, rat ascites hepatoma cells, in vitro only under hypoxic but not normoxic condition. Intraperitoneal administration of TOP3 prolonged life span of the rats with AH130 derived malignant ascites. Sixty percent of the treated rats were cured of ascites without recurrence for more than six months, in contrast all untreated rats died within 20 days after tumor cell inoculation. These results strongly suggest that TOP3 would provide a new strategy for hypoxia targeting therapy and that the combination of TOP3 with radiotherapy or chemotherapy may provide a new strategy for annihilating malignant tumors

  16. Theranostic Liposomes with Hypoxia-Activated Prodrug to Effectively Destruct Hypoxic Tumors Post-Photodynamic Therapy.

    Science.gov (United States)

    Feng, Liangzhu; Cheng, Liang; Dong, Ziliang; Tao, Danlei; Barnhart, Todd E; Cai, Weibo; Chen, Meiwan; Liu, Zhuang

    2017-01-24

    Photodynamic therapy (PDT), a noninvasive cancer therapeutic method triggered by light, would lead to severe tumor hypoxia after treatment. Utilizing a hypoxia-activated prodrug, AQ4N, which only shows toxicity to cancer cells under hypoxic environment, herein, a multipurpose liposome is prepared by encapsulating hydrophilic AQ4N and hydrophobic hexadecylamine conjugated chlorin e6 (hCe6), a photosensitizer, into its aqueous cavity and hydrophobic bilayer, respectively. After chelating a 64 Cu isotope with Ce6, the obtained AQ4N- 64 Cu-hCe6-liposome is demonstrated to be an effective imaging probe for in vivo positron emission tomography, which together with in vivo fluorescence and photoacoustic imaging uncovers efficient passive homing of those liposomes after intravenous injection. After being irradiated with the 660 nm light-emitting diode light, the tumor bearing mice with injection of AQ4N-hCe6-liposome show severe tumor hypoxia, which in turn would trigger activation of AQ4N, and finally contributes to remarkably improved cancer treatment outcomes via sequential PDT and hypoxia-activated chemotherapy. This work highlights a liposome-based theranostic nanomedicine that could utilize tumor hypoxia, a side effect of PDT, to trigger chemotherapy, resulting in greatly improved efficacy compared to conventional cancer PDT.

  17. Oxygen Sensitivity of Reporter Genes: Implications for Preclinical Imaging of Tumor Hypoxia

    Directory of Open Access Journals (Sweden)

    Ivana Cecic

    2007-07-01

    Full Text Available Reporter gene techniques have been applied toward studying the physiologic phenomena associated with tumor hypoxia, a negative prognostic indicator. The purpose of this study was to assess the potential adverse effects of hypoxic conditions on the effectiveness of four commonly used reporter genes: Renilla luciferase, monomeric red fluorescent protein, thymidine kinase, and lacZ. Tumor-forming A375 cells expressing a trifusion reporter consisting of Renilla luciferase, monomeric red fluorescent protein, and thymidine kinase were subjected to decreasing oxygen tensions and assayed for reporter expression and activity. A375 cells expressing β-galactosidase were similarly exposed to hypoxia, with activity of the reporter monitored by cleavage of the fluorescent substrate 7-hydroxy-9H-(1, 3-dichloro-9, 9-dimethylacridin-2-one-β-galactoside (DDAOG. Generation of signal in in vivo tumor models expressing bioluminescent or β-galactosidase reporters were also examined over the course of hypoxic stresses, either by tumor clamping or the antivascular agent 5, 6-dimethylxanthenone-4-acetic acid (DMXAA. Our findings indicate that bioluminescent and fluorescent reporter activity are decreased under hypoxia despite minimal variations in protein production, whereas β-galactosidase reporter activity per unit protein was unchanged. These results demonstrate that combining β-galactosidase with the DDAOG optical probe may be a robust reporter system for the in vivo study of tumor hypoxia.

  18. Hypoxia Up-Regulates Galectin-3 in Mammary Tumor Progression and Metastasis

    NARCIS (Netherlands)

    de Oliveira, Joana T; Ribeiro, Cláudia; Barros, Rita; Gomes, Catarina; de Matos, Augusto J; Reis, Celso A; Rutteman, Gerard R; Gärtner, Fátima

    2015-01-01

    The tumor microenvironment encompasses several stressful conditions for cancer cells such as hypoxia, oxidative stress and pH alterations. Galectin-3, a well-studied member of the beta-galactoside-binding animal family of lectins has been implicated in multiple steps of metastasis as cell-cell and

  19. Hypoxia-Induced Signaling Promotes Prostate Cancer Progression: Exosomes Role as Messenger of Hypoxic Response in Tumor Microenvironment

    Science.gov (United States)

    Deep, Gagan; Panigrahi, Gati K.

    2017-01-01

    Prostate cancer (PCA) is the leading malignancy in men and the second leading cause of cancer-related deaths. Hypoxia (low O2 condition) is considered an early event in prostate carcinogenesis associated with an aggressive phenotype. In fact, clinically, hypoxia and hypoxia-related biomarkers are associated with treatment failure and disease progression. Hypoxia-inducible factor 1 (HIF-1) is the key factor that is activated under hypoxia, and mediates adaptation of cells to hypoxic conditions through regulating the expression of genes associated with angiogenesis, epithelial-to-mesenchymal transition (EMT), metastasis, survival, proliferation, metabolism, stemness, hormone-refractory progression, and therapeutic resistance. Besides HIF-1, several other signaling pathways including PI3K/Akt/mTOR, NADPH oxidase (NOX), Wnt/β-catenin, and Hedgehog are activated in cancer cells under hypoxic conditions, and also contribute in hypoxia-induced biological effects in HIF-1-dependent and -independent manners. Hypoxic cancer cells cause extensive changes in the tumor microenvironment both local and distant, and recent studies have provided ample evidence supporting the crucial role of nanosized vesicles “exosomes” in mediating hypoxia-induced tumor microenvironment remodeling. Exosomes’ role has been reported in hypoxia-induced angiogenesis, stemness, activation of cancer-associated fibroblasts (CAFs), and EMT. Together, existing literature suggests that hypoxia plays a predominant role in PCA growth and progression, and PCA could be effectively prevented and treated via targeting hypoxia/hypoxia-related signaling pathways. PMID:27279239

  20. Hypoxia Responsive, Tumor Penetrating Lipid Nanoparticles for Delivery of Chemotherapeutics to Pancreatic Cancer Cell Spheroids.

    Science.gov (United States)

    Kulkarni, Prajakta; Haldar, Manas K; Katti, Preeya; Dawes, Courtney; You, Seungyong; Choi, Yongki; Mallik, Sanku

    2016-08-17

    Solid tumors are often poorly irrigated due to structurally compromised microcirculation. Uncontrolled multiplication of cancer cells, insufficient blood flow, and the lack of enough oxygen and nutrients lead to the development of hypoxic regions in the tumor tissues. As the partial pressure of oxygen drops below the necessary level (10 psi), the cancer cells modulate their genetic makeup to survive. Hypoxia triggers tumor progression by enhancing angiogenesis, cancer stem cell production, remodeling of the extracellular matrix, and epigenetic changes in the cancer cells. However, the hypoxic regions are usually located deep in the tumors and are usually inaccessible to the intravenously injected drug carrier or the drug. Considering the designs of the reported nanoparticles, it is likely that the drug is delivered to the peripheral tumor tissues, close to the blood vessels. In this study, we prepared lipid nanoparticles (LNs) comprising the synthesized hypoxia-responsive lipid and a peptide-lipid conjugate. We observed that the resultant LNs penetrated to the hypoxic regions of the tumors. Under low oxygen partial pressure, the hypoxia-responsive lipid undergoes reduction, destabilizing the lipid membrane, and releasing encapsulated drugs from the nanoparticles. We demonstrated the results employing spheroidal cultures of the pancreatic cancer cells BxPC-3. We observed that the peptide-decorated, drug encapsulated LNs reduced the viability of pancreatic cancer cells of the spheroids to 35% under hypoxic conditions.

  1. Optimization of biguanide derivatives as selective antitumor agents blocking adaptive stress responses in the tumor microenvironment

    Directory of Open Access Journals (Sweden)

    Narise K

    2014-06-01

    Full Text Available Kosuke Narise, Kensuke Okuda, Yukihiro Enomoto, Tasuku Hirayama, Hideko Nagasawa Laboratory of Pharmaceutical and Medicinal Chemistry, Gifu Pharmaceutical University, Daigaku-nishi, Gifu, Japan Abstract: Adaptive cellular responses resulting from multiple microenvironmental stresses, such as hypoxia and nutrient deprivation, are potential novel drug targets for cancer treatment. Accordingly, we focused on developing anticancer agents targeting the tumor microenvironment (TME. In this study, to search for selective antitumor agents blocking adaptive responses in the TME, thirteen new compounds, designed and synthesized on the basis of the arylmethylbiguanide scaffold of phenformin, were used in structure activity relationship studies of inhibition of hypoxia inducible factor (HIF-1 and unfolded protein response (UPR activation and of selective cytotoxicity under glucose-deprived stress conditions, using HT29 cells. We conducted luciferase reporter assays using stable cell lines expressing either an HIF-1-responsive reporter gene or a glucose-regulated protein 78 promoter-reporter gene, which were induced by hypoxia and glucose deprivation stress, respectively, to screen for TME-targeting antitumor drugs. The guanidine analog (compound 2, obtained by bioisosteric replacement of the biguanide group, had activities comparable with those of phenformin (compound 1. Introduction of various substituents on the phenyl ring significantly affected the activities. In particular, the o-methylphenyl analog compound 7 and the o-chlorophenyl analog compound 12 showed considerably more potent inhibitory effects on HIF-1 and UPR activation than did phenformin, and excellent selective cytotoxicity under glucose deprivation. These compounds, therefore, represent an improvement over phenformin. They also suppressed HIF-1- and UPR-related protein expression and secretion of vascular endothelial growth factor-A. Moreover, these compounds exhibited significant

  2. Inhibition of Vascular Endothelial Growth Factor A and Hypoxia-Inducible Factor 1α Maximizes the Effects of Radiation in Sarcoma Mouse Models Through Destruction of Tumor Vasculature

    International Nuclear Information System (INIS)

    Lee, Hae-June; Yoon, Changhwan; Park, Do Joong; Kim, Yeo-Jung; Schmidt, Benjamin; Lee, Yoon-Jin; Tap, William D.; Eisinger-Mathason, T.S. Karin; Choy, Edwin; Kirsch, David G.; Simon, M. Celeste

    2015-01-01

    Purpose: To examine the addition of genetic or pharmacologic inhibition of hypoxia-inducible factor 1α (HIF-1α) to radiation therapy (RT) and vascular endothelial growth factor A (VEGF-A) inhibition (ie trimodality therapy) for soft-tissue sarcoma. Methods and Materials: Hypoxia-inducible factor 1α was inhibited using short hairpin RNA or low metronomic doses of doxorubicin, which blocks HIF-1α binding to DNA. Trimodality therapy was examined in a mouse xenograft model and a genetically engineered mouse model of sarcoma, as well as in vitro in tumor endothelial cells (ECs) and 4 sarcoma cell lines. Results: In both mouse models, any monotherapy or bimodality therapy resulted in tumor growth beyond 250 mm 3 within the 12-day treatment period, but trimodality therapy with RT, VEGF-A inhibition, and HIF-1α inhibition kept tumors at <250 mm 3 for up to 30 days. Trimodality therapy on tumors reduced HIF-1α activity as measured by expression of nuclear HIF-1α by 87% to 95% compared with RT alone, and cytoplasmic carbonic anhydrase 9 by 79% to 82%. Trimodality therapy also increased EC-specific apoptosis 2- to 4-fold more than RT alone and reduced microvessel density by 75% to 82%. When tumor ECs were treated in vitro with trimodality therapy under hypoxia, there were significant decreases in proliferation and colony formation and increases in DNA damage (as measured by Comet assay and γH2AX expression) and apoptosis (as measured by cleaved caspase 3 expression). Trimodality therapy had much less pronounced effects when 4 sarcoma cell lines were examined in these same assays. Conclusions: Inhibition of HIF-1α is highly effective when combined with RT and VEGF-A inhibition in blocking sarcoma growth by maximizing DNA damage and apoptosis in tumor ECs, leading to loss of tumor vasculature

  3. Inhibition of vascular endothelial growth factor A and hypoxia-inducible factor 1α maximizes the effects of radiation in sarcoma mouse models through destruction of tumor vasculature.

    Science.gov (United States)

    Lee, Hae-June; Yoon, Changhwan; Park, Do Joong; Kim, Yeo-Jung; Schmidt, Benjamin; Lee, Yoon-Jin; Tap, William D; Eisinger-Mathason, T S Karin; Choy, Edwin; Kirsch, David G; Simon, M Celeste; Yoon, Sam S

    2015-03-01

    To examine the addition of genetic or pharmacologic inhibition of hypoxia-inducible factor 1α (HIF-1α) to radiation therapy (RT) and vascular endothelial growth factor A (VEGF-A) inhibition (ie trimodality therapy) for soft-tissue sarcoma. Hypoxia-inducible factor 1α was inhibited using short hairpin RNA or low metronomic doses of doxorubicin, which blocks HIF-1α binding to DNA. Trimodality therapy was examined in a mouse xenograft model and a genetically engineered mouse model of sarcoma, as well as in vitro in tumor endothelial cells (ECs) and 4 sarcoma cell lines. In both mouse models, any monotherapy or bimodality therapy resulted in tumor growth beyond 250 mm(3) within the 12-day treatment period, but trimodality therapy with RT, VEGF-A inhibition, and HIF-1α inhibition kept tumors at <250 mm(3) for up to 30 days. Trimodality therapy on tumors reduced HIF-1α activity as measured by expression of nuclear HIF-1α by 87% to 95% compared with RT alone, and cytoplasmic carbonic anhydrase 9 by 79% to 82%. Trimodality therapy also increased EC-specific apoptosis 2- to 4-fold more than RT alone and reduced microvessel density by 75% to 82%. When tumor ECs were treated in vitro with trimodality therapy under hypoxia, there were significant decreases in proliferation and colony formation and increases in DNA damage (as measured by Comet assay and γH2AX expression) and apoptosis (as measured by cleaved caspase 3 expression). Trimodality therapy had much less pronounced effects when 4 sarcoma cell lines were examined in these same assays. Inhibition of HIF-1α is highly effective when combined with RT and VEGF-A inhibition in blocking sarcoma growth by maximizing DNA damage and apoptosis in tumor ECs, leading to loss of tumor vasculature. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Imaging hypoxia after oxygenation-modification: comparing [18F]FMISO autoradiography with pimonidazole immunohistochemistry in human xenograft tumors.

    NARCIS (Netherlands)

    Troost, E.G.C.; Laverman, P.; Kaanders, J.H.A.M.; Philippens, M.E.P.; Lok, J.; Oyen, W.J.G.; Kogel, A.J. van der; Boerman, O.C.; Bussink, J.

    2006-01-01

    PURPOSE: Hypoxia is one of the reasons for radiation therapy resistance. Positron emission tomography using (18)F-labeled misonidazole ([(18)F]FMISO) is a non-invasive method of imaging tumor hypoxia. Aim of this study was to validate [(18)F]FMISO against the clinically most widely used hypoxic cell

  5. Hypoxia increases membrane metallo-endopeptidase expression in a novel lung cancer ex vivo model - role of tumor stroma cells

    NARCIS (Netherlands)

    K. Leithner (Katharina); C. Wohlkoenig (Christoph); E. Stacher (Elvira); J. Lindenmann (Jörg); N.A. Hofmann (Nicole); B. Gallé (Birgit); C. Guelly (Christian); F. Quehenberger (Franz); P. Stiegler (Philipp); F.-M. Smolle-Jüttner (Freyja-Maria); J.N.J. Philipsen (Sjaak); H.H. Popper (Helmut); A. Hrzenjak (Andelko); A. Olschewski (Andrea); H. Olschewski (Horst)

    2014-01-01

    textabstractBackground: Hypoxia-induced genes are potential targets in cancer therapy. Responses to hypoxia have been extensively studied in vitro, however, they may differ in vivo due to the specific tumor microenvironment. In this study gene expression profiles were obtained from fresh human lung

  6. Hypoxia-inducible factor 1–mediated characteristic features of cancer cells for tumor radioresistance

    International Nuclear Information System (INIS)

    Harada, Hiroshi

    2016-01-01

    Tumor hypoxia has been attracting increasing attention in the fields of radiation biology and oncology since Thomlinson and Gray detected hypoxic cells in malignant solid tumors and showed that they exert a negative impact on the outcome of radiation therapy. This unfavorable influence has, at least partly, been attributed to cancer cells acquiring a radioresistant phenotype through the activation of the transcription factor, hypoxia-inducible factor 1 (HIF-1). On the other hand, accumulating evidence has recently revealed that, even though HIF-1 is recognized as an important regulator of cellular adaptive responses to hypoxia, it may not become active and induce tumor radioresistance under hypoxic conditions only. The mechanisms by which HIF-1 is activated in cancer cells not only under hypoxic conditions, but also under normoxic conditions, through cancer-specific genetic alterations and the resultant imbalance in intermediate metabolites have been summarized herein. The relevance of the HIF-1–mediated characteristic features of cancer cells, such as the production of antioxidants through reprogramming of the glucose metabolic pathway and cell cycle regulation, for tumor radioresistance has also been reviewed

  7. NADPH oxidase subunit 4-mediated reactive oxygen species contribute to cycling hypoxia-promoted tumor progression in glioblastoma multiforme.

    Directory of Open Access Journals (Sweden)

    Chia-Hung Hsieh

    Full Text Available Cycling and chronic tumor hypoxia are involved in tumor development and growth. However, the impact of cycling hypoxia and its molecular mechanism on glioblastoma multiforme (GBM progression remain unclear.Glioblastoma cell lines, GBM8401 and U87, and their xenografts were exposed to cycling hypoxic stress in vitro and in vivo. Reactive oxygen species (ROS production in glioblastoma cells and xenografts was assayed by in vitro ROS analysis and in vivo molecular imaging studies. NADPH oxidase subunit 4 (Nox4 RNAi-knockdown technology was utilized to study the role of Nox4 in cycling hypoxia-mediated ROS production and tumor progression. Furthermore, glioblastoma cells were stably transfected with a retroviral vector bearing a dual reporter gene cassette that allowed for dynamic monitoring of HIF-1 signal transduction and tumor cell growth in vitro and in vivo, using optical and nuclear imaging. Tempol, an antioxidant compound, was used to investigate the impact of ROS on cycling hypoxia-mediated HIF-1 activation and tumor progression.Glioblastoma cells and xenografts were compared under cycling hypoxic and normoxic conditions; upregulation of NOX4 expression and ROS levels were observed under cycling hypoxia in glioblastoma cells and xenografts, concomitant with increased tumor cell growth in vitro and in vivo. However, knockdown of Nox4 inhibited these effects. Moreover, in vivo molecular imaging studies demonstrated that Tempol is a good antioxidant compound for inhibiting cycling hypoxia-mediated ROS production, HIF-1 activation, and tumor growth. Immunofluorescence imaging and flow cytometric analysis for NOX4, HIF-1 activation, and Hoechst 3342 in glioblastoma also revealed high localized NOX4 expression predominantly in potentially cycling hypoxic areas with HIF-1 activation and blood perfusion within the endogenous solid tumor microenvironment.Cycling hypoxia-induced ROS via Nox4 is a critical aspect of cancer biology to consider for

  8. Hypoxia Pathway Proteins As Central Mediators of Metabolism in the Tumor Cells and Their Microenvironment

    Directory of Open Access Journals (Sweden)

    Sundary Sormendi

    2018-01-01

    Full Text Available Low oxygen tension or hypoxia is a determining factor in the course of many different processes in animals, including when tissue expansion and cellular metabolism result in high oxygen demands that exceed its supply. This is mainly happening when cells actively proliferate and the proliferating mass becomes distant from the blood vessels, such as in growing tumors. Metabolic alterations in response to hypoxia can be triggered in a direct manner, such as the switch from oxidative phosphorylation to glycolysis or inhibition of fatty acid desaturation. However, as the modulated action of hypoxia-inducible factors or the oxygen sensors (prolyl hydroxylase domain-containing enzymes can also lead to changes in enzyme expression, these metabolic changes can also be indirect. With this review, we want to summarize our current knowledge of the hypoxia-induced changes in metabolism during cancer development, how they are affected in the tumor cells and in the cells of the microenvironment, most prominently in immune cells.

  9. Deriving mechanisms responsible for the lack of correlation between hypoxia and acidity in solid tumors.

    Directory of Open Access Journals (Sweden)

    Hamid R Molavian

    Full Text Available Hypoxia and acidity are two main microenvironmental factors intimately associated with solid tumors and play critical roles in tumor growth and metastasis. The experimental results of Helmlinger and colleagues (Nature Medicine 3, 177, 1997 provide evidence of a lack of correlation between these factors on the micrometer scale in vivo and further show that the distribution of pH and pO(2 are heterogeneous. Here, using computational simulations, grounded in these experimental results, we show that the lack of correlation between pH and pO(2 and the heterogeneity in their shapes are related to the heterogeneous concentration of buffers and oxygen in the blood vessels, further amplified by the network of blood vessels and the cell metabolism. We also demonstrate that, although the judicious administration of anti-angiogenesis agents (normalization process in tumors may lead to recovery of the correlation between hypoxia and acidity, it may not normalize the pH throughout the whole tumor. However, an increase in the buffering capacity inside the blood vessels does appear to increase the extracellular pH throughout the whole tumor. Based on these results, we propose that the application of anti-angiogenic agents and at the same time increasing the buffering capacity of the tumor extracellular environment may be the most efficient way of normalizing the tumor microenvironment. As a by-product of our simulation we show that the recently observed lack of correlation between glucose consumption and hypoxia in cells which rely on respiration is related to the inhomogeneous consumption of glucose to oxygen concentration. We also demonstrate that this lack of correlation in cells which rely on glycolysis could be related to the heterogeneous concentration of oxygen inside the blood vessels.

  10. Tumor hypoxia modulates podoplanin/CCL21 interactions in CCR7+ NK cell recruitment and CCR7+ tumor cell mobilization.

    Science.gov (United States)

    Tejchman, Anna; Lamerant-Fayel, Nathalie; Jacquinet, Jean-Claude; Bielawska-Pohl, Aleksandra; Mleczko-Sanecka, Katarzyna; Grillon, Catherine; Chouaib, Salem; Ugorski, Maciej; Kieda, Claudine

    2017-05-09

    Podoplanin (PDPN), an O-glycosylated, transmembrane, mucin-type glycoprotein, is expressed by cancer associated fibroblasts (CAFs). In malignant transformation, PDPN is subjected to changes and its role is yet to be established. Here we show that it is involved in modulating the activity of the CCL21/CCR7 chemokine/receptor axis in a hypoxia-dependent manner. In the present model, breast cancer MDA-MB-231 cells and NKL3 cells express the surface CCR7 receptor for CCL21 chemokine which is a potent chemoattractant able to bind to PDPN. The impact of the CCL21/CCR7 axis in the molecular mechanism of the adhesion of NKL3 cells and of MDA-MB-231 breast cancer cells was reduced in a hypoxic tumor environment. In addition to its known effect on migration, CCL21/CCR7 interaction was shown to allow NK cell adhesion to endothelial cells (ECs) and its reduction by hypoxia. A PDPN expressing model of CAFs made it possible to demonstrate the same CCL21/CCR7 axis involvement in the tumor cells to CAFs recognition mechanism through PDPN binding of CCL21. PDPN was induced by hypoxia and its overexpression undergoes a reduction of adhesion, making it an anti-adhesion molecule in the absence of CCL21, in the tumor. CCL21/CCR7 modulated NK cells/ECs and MDA-MB-231 cells/CAF PDPN-dependent interactions were further shown to be linked to hypoxia-dependent microRNAs as miRs: miR-210 and specifically miR-21, miR-29b which influence PDPN expression.

  11. Modulation of tumor hypoxia by topical formulations with vasodilators for enhancing therapy.

    Science.gov (United States)

    Abramovic, Zrinka; Hou, Huagang; Julijana, Kristl; Sentjurc, Marjeta; Lariviere, Jean P; Swartz, Harold M; Khan, Nadeem

    2011-01-01

    Tumor hypoxia is a well known therapeutic problem which contributes to radioresistance and aggressive tumor characteristics. Lack of techniques for repeated measurements of tumor oxygenation (pO(2), partial pressure of oxygen) has restricted the optimization of hypoxia modifying methods and their efficacious application with radiotherapy. We have investigated a non-invasive method to enhance tissue pO(2) of peripheral tumors using topical application of formulations with BN (Benzyl Nicotinate), a vasodilator, and have used EPR (Electron Paramagnetic Resonance) oximetry to follow its effect on tumor oxygenation.We incorporated 2.5% BN in both hydrogel and microemulsions and investigated the effects on pO(2) of subcutaneous RIF-1 (Radiation Induced Fibrosarcoma) tumors in C3H mice. The experiments were repeated for five consecutive days. The topical application of BN in hydrogel led to a significant increase from a pre-treatment pO(2) of 9.3 mmHg to 11 - 16 mmHg at 30 - 50 min on day 1. However, the magnitude and the time of significant increase in pO(2) decreased with repeated topical applications. The BN in a microemulsion resulted in a significant increase from a baseline pO(2) of 8.8 mmHg to 13 - 18 mmHg at 10 - 50 min on day 1. Experiments repeated on subsequent days showed a decline in the magnitude of pO(2) increase on repeated applications. No significant change in tumor pO(2) was observed in experiments with formulations without BN (vehicle only).EPR oximetry was successfully used to follow the temporal changes in tumor pO(2) during repeated applications for five consecutive days. This approach can be potentially used to enhance radiotherapeutic outcome by scheduling radiation doses when an increase in tumor pO(2) is observed after topical applications of BN formulations.

  12. Sulforaphane reduces molecular response to hypoxia in ovarian tumor cells independently of their resistance to chemotherapy.

    Science.gov (United States)

    Pastorek, Michal; Simko, Veronika; Takacova, Martina; Barathova, Monika; Bartosova, Maria; Hunakova, Luba; Sedlakova, Olga; Hudecova, Sona; Krizanova, Olga; Dequiedt, Franck; Pastorekova, Silvia; Sedlak, Jan

    2015-07-01

    One of the recently emerging anticancer strategies is the use of natural dietary compounds, such as sulforaphane, a cancer-chemopreventive isothiocyanate found in broccoli. Based on the growing evidence, sulforaphane acts through molecular mechanisms that interfere with multiple oncogenic pathways in diverse tumor cell types. Herein, we investigated the anticancer effects of bioavailable concentrations of sulforaphane in ovarian carcinoma cell line A2780 and its two derivatives, adriamycin-resistant A2780/ADR and cisplatin-resistant A2780/CP cell lines. Since tumor microenvironment is characterized by reduced oxygenation that induces aggressive tumor phenotype (such as increased invasiveness and resistance to chemotherapy), we evaluated the effects of sulforaphane in ovarian cancer cells exposed to hypoxia (2% O2). Using the cell-based reporter assay, we identified several oncogenic pathways modulated by sulforaphane in hypoxia by activating anticancer responses (p53, ARE, IRF-1, Pax-6 and XRE) and suppressing responses supporting tumor progression (AP-1 and HIF-1). We further showed that sulforaphane decreases the level of HIF-1α protein without affecting its transcription and stability. It can also diminish transcription and protein level of the HIF-1 target, CA IX, which protects tumor cells from hypoxia-induced pH imbalance and facilitates their migration/invasion. Accordingly, sulforaphane treatment leads to diminished pH regulation and reduced migration of ovarian carcinoma cells. These effects occur in all three ovarian cell lines suggesting that sulforaphane can overcome the chemoresistance of cancer cells. This offers a path potentially exploitable in sensitizing resistant cancer cells to therapy, and opens a window for the combined treatments of sulforaphane either with conventional chemotherapy, natural compounds, or with other small molecules.

  13. Potential role of the glycolytic oscillator in acute hypoxia in tumors

    Science.gov (United States)

    Che Fru, Leonard; Adamson, Erin B.; Campos, David D.; Fain, Sean B.; Jacques, Steven L.; van der Kogel, Albert J.; Nickel, Kwang P.; Song, Chihwa; Kimple, Randall J.; Kissick, Michael W.

    2015-12-01

    Tumor acute hypoxia has a dynamic component that is also, at least partially, coherent. Using blood oxygen level dependent magnetic resonance imaging, we observed coherent oscillations in hemoglobin saturation dynamics in cell line xenograft models of head and neck squamous cell carcinoma. We posit a well-established biochemical nonlinear oscillatory mechanism called the glycolytic oscillator as a potential cause of the coherent oscillations in tumors. These data suggest that metabolic changes within individual tumor cells may affect the local tumor microenvironment including oxygen availability and therefore radiosensitivity. These individual cells can synchronize the oscillations in patches of similar intermediate glucose levels. These alterations have potentially important implications for radiation therapy and are a potential target for optimizing the cancer response to radiation.

  14. Recombinant human endostatin improves tumor vasculature and alleviates hypoxia in Lewis lung carcinoma

    International Nuclear Information System (INIS)

    Peng Fang; Wang Jin; Zou Yi; Bao Yong; Huang Wenlin; Chen Guangming; Luo Xianrong; Chen Ming

    2011-01-01

    Objective: To investigate whether recombinant human endostatin can create a time window of vascular normalization prior to vascular pruning to alleviate hypoxia in Lewis lung carcinoma in mice. Methods: Kinetic changes in morphology of tumor vasculature in response to recombinant human endostatin were detected under a confocal microscope with immunofluorescent staining in Lewis lung carcinomas in mice. The hypoxic cell fraction of different time was assessed with immunohistochemical staining . Effects on tumor growth were monitored as indicated in the growth curve of tumors . Results: Compared with the control group vascularity of the tumors was reduced over time by recombinant human endostatin treatment and significantly regressed for 9 days. During the treatment, pericyte coverage increased at day 3, increased markedly at day 5, and fell again at day 7. The vascular basement membrane was thin and closely associated with endothelial cells after recombinant human endostatin treatment, but appeared thickened, loosely associated with endothelial cells in control tumors. The decrease in hypoxic cell fraction at day 5 after treatment was also found. Tumor growth was not accelerated 5 days after recombinant human endostatin treatment. Conclusions: Recombinant human endostatin can normalize tumor vasculature within day 3 to 7, leading to improved tumor oxygenation. The results provide important experimental basis for combining recombinant human endostatin with radiation therapy in human tumors. (authors)

  15. Hypoxia upregulates Bcl-2 expression and suppresses interferon-gamma induced antiangiogenic activity in human tumor derived endothelial cells.

    LENUS (Irish Health Repository)

    Wang, Jiang Huai

    2012-02-03

    BACKGROUND: Hypoxia in solid tumors potentially stimulates angiogenesis by promoting vascular endothelial growth factor (VEGF) production and upregulating VEGF receptor expression. However, it is unknown whether hypoxia can modulate the effect of anti-angiogenic treatment on tumor-derived endothelium. METHODS: Human tumor-derived endothelial cells (HTDEC) were freshly isolated from surgically removed human colorectal tumors by collagenase\\/DNase digestion and Percol gradient sedimentation. Cell proliferation was assessed by measuring BrdU incorporation, and capillary tube formation was measured using Matrigel. Cell apoptosis was assessed by flow cytometry and ELISA, and Bcl-2 expression was detected by Western blot analysis. RESULTS: Under aerobic culture conditions (5% CO2 plus 21% O2) HTDEC expressed less Bcl-2 and were more susceptible to IFN-gamma-induced apoptosis with significant reductions in both cell proliferation and capillary tube formation, when compared with normal human macrovascular and microvascular EC. Following exposure of HTDEC to hypoxia (5% CO2 plus 2% O2), IFN-gamma-induced cell apoptosis, and antiangiogenic activity (i.e. an inhibition in cell proliferation and capillary tube formation) in HTDEC were markedly attenuated. This finding correlated with hypoxia-induced upregulation of Bcl-2 expression in HTDEC. CONCLUSIONS: These results indicate that hypoxia can protect HTDEC against IFN-gamma-mediated cell death and antiangiogenic activity, and suggest that improvement of tumor oxygenation may potentiate the efficacy of anti-cancer therapies specifically targeting the inhibition of tumor angiogenesis.

  16. Hypoxia-Mediated Epigenetic Regulation of Stemness in Brain Tumor Cells.

    Science.gov (United States)

    Prasad, Pankaj; Mittal, Shivani Arora; Chongtham, Jonita; Mohanty, Sujata; Srivastava, Tapasya

    2017-06-01

    Activation of pluripotency regulatory circuit is an important event in solid tumor progression and the hypoxic microenvironment is known to enhance the stemness feature of some cells. The distinct population of cancer stem cells (CSCs)/tumor initiating cells exist in a niche and augment invasion, metastasis, and drug resistance. Previously, studies have reported global hypomethylation and site-specific aberrant methylation in gliomas along with other epigenetic modifications as important contributors to genomic instability during glioma progression. Here, we have demonstrated the role of hypoxia-mediated epigenetic modifications in regulating expression of core pluripotency factors, OCT4 and NANOG, in glioma cells. We observe hypoxia-mediated induction of demethylases, ten-eleven-translocation (TET) 1 and 3, but not TET2 in our cell-line model. Immunoprecipitation studies reveal active demethylation and direct binding of TET1 and 3 at the Oct4 and Nanog regulatory regions. Tet1 and 3 silencing assays further confirmed induction of the pluripotency pathway involving Oct4, Nanog, and Stat3, by these paralogues, although with varying degrees. Knockdown of Tet1 and Tet3 inhibited the formation of neurospheres in hypoxic conditions. We observed independent roles of TET1 and TET3 in differentially regulating pluripotency and differentiation associated genes in hypoxia. Overall, this study demonstrates an active demethylation in hypoxia by TET1 and 3 as a mechanism of Oct4 and Nanog overexpression thus contributing to the formation of CSCs in gliomas. Stem Cells 2017;35:1468-1478. © 2017 AlphaMed Press.

  17. Blockade of processing/activation of caspase-3 by hypoxia

    International Nuclear Information System (INIS)

    Han, Sang Hee; Kim, Moonil; Park, Kyoungsook; Kim, Tae-Hyoung; Seol, Dai-Wu

    2008-01-01

    Tumor hypoxia, which is caused by the rapid proliferation of tumor cells and aberrant vasculature in tumors, results in inadequate supplies of oxygen and nutrients to tumor cells. Paradoxically, these unfavorable growth conditions benefit tumor cell survival, although the mechanism is poorly understood. We have demonstrated for the first time that hypoxia inhibits TRAIL-induced apoptosis by blocking translocation of Bax from cytosol to the mitochondria in tumor cells. However, it is largely unknown how hypoxia-inhibited Bax translocation attenuates TRAIL-induced apoptosis. Here, we demonstrate that despite its inhibitory activity in TRAIL-induced apoptosis, hypoxia does not affect TRAIL-triggered proximal apoptotic signaling events, including caspase-8 activation and Bid cleavage. Instead, hypoxia inhibited processing of caspase-3, leading to incomplete activation of the caspase. Importantly, hypoxia-blocked translocation of Bax to the mitochondria significantly inhibited releasing the mitochondrial factors, such as cytochrome c and Smac/DIABLO, to the cytosol in response to TRAIL. It is well-known that complete processing/activation of caspase-3 requires Smac/DIABLO released from mitochondria. Therefore, our data indicate that an engagement of the apoptotic mitochondrial events leading to caspase-3 activation is blocked by hypoxia. Our data shed new light on understanding of the apoptotic signal transduction and targets regulated by tumor hypoxia

  18. The retinoblastoma protein regulates hypoxia-inducible genetic programs, tumor cell invasiveness and neuroendocrine differentiation in prostate cancer cells

    Science.gov (United States)

    Labrecque, Mark P.; Takhar, Mandeep K.; Nason, Rebecca; Santacruz, Stephanie; Tam, Kevin J.; Massah, Shabnam; Haegert, Anne; Bell, Robert H.; Altamirano-Dimas, Manuel; Collins, Colin C.; Lee, Frank J.S.; Prefontaine, Gratien G.; Cox, Michael E.; Beischlag, Timothy V.

    2016-01-01

    Loss of tumor suppressor proteins, such as the retinoblastoma protein (Rb), results in tumor progression and metastasis. Metastasis is facilitated by low oxygen availability within the tumor that is detected by hypoxia inducible factors (HIFs). The HIF1 complex, HIF1α and dimerization partner the aryl hydrocarbon receptor nuclear translocator (ARNT), is the master regulator of the hypoxic response. Previously, we demonstrated that Rb represses the transcriptional response to hypoxia by virtue of its association with HIF1. In this report, we further characterized the role Rb plays in mediating hypoxia-regulated genetic programs by stably ablating Rb expression with retrovirally-introduced short hairpin RNA in LNCaP and 22Rv1 human prostate cancer cells. DNA microarray analysis revealed that loss of Rb in conjunction with hypoxia leads to aberrant expression of hypoxia-regulated genetic programs that increase cell invasion and promote neuroendocrine differentiation. For the first time, we have established a direct link between hypoxic tumor environments, Rb inactivation and progression to late stage metastatic neuroendocrine prostate cancer. Understanding the molecular pathways responsible for progression of benign prostate tumors to metastasized and lethal forms will aid in the development of more effective prostate cancer therapies. PMID:27015368

  19. Significance of hypoxia for tumor response to radiation: Mathematical modeling and analysis of local control and clonogenic assay data

    International Nuclear Information System (INIS)

    Buffa, Francesca Meteora

    2002-01-01

    Various hypotheses for radiation local tumor control probability (ltcp) were modeled, and assessed against local tumor control (LTC) and clonogenic assay (CA) data. For head-and-neck tumors receiving low-LET external-beam irradiation, the best model was a Poisson ltcp accounting for cell repopulation, hypoxia, and tumor volume dependence of radiosensitivity (α). This confirmed that hypoxia is limiting LTC of these tumors, with the magnitude depending upon tumor volume. However, LTC of cervical carcinoma receiving external-beam irradiation and brachytherapy was well described by a model not accounting for hypoxia. Furthermore, when the survival fraction at 2 Gy (SF 2 ) and colony forming efficiency (CFE) measured for individual patients were incorporated into this model, very good correlation with LTC was seen (p=0.0004). After multivariate analysis, this model was the best independent prognostic factor for LTC and patient survival. Furthermore, no difference in prediction was seen when a model based on birth-and-death stochastic theory was used. Two forms of hypoxia are known to be present in tumors: diffusion-limited, chronic hypoxia (CH), and acute, transient hypoxia (TH). A modeling study on WiDr multicellular spheroids showed that the CH effect on LTC is significantly lower than expected from CA. This could arise from energy charge depletion accompanying CH, reducing the number of proliferating clonogenic cells that can repair radiation damage, and thus mitigating the radioresistance of CH cells. This suggests that TH, rather than CH, may be the limiting factor for in vivo LTC. Finally, by computing ltcp using Monte Carlo calculated dose distributions, it was shown that Monte Carlo statistical noise can cause an underestimation of ltcp, with the magnitude depending upon the model hypotheses

  20. Phosphorescent light-emitting iridium complexes serve as a hypoxia-sensing probe for tumor imaging in living animals

    Science.gov (United States)

    Takeuchi, Toshiyuki; Zhang, Shaojuan; Negishi, Kazuya; Yoshihara, Toshitada; Hosaka, Masahiro; Tobita, Seiji

    2010-02-01

    Iridium complex, a promising organic light-emitting diode material for next generation television and computer displays, emits phosphorescence. Phosphorescence is quenched by oxygen. We used this oxygen-quenching feature for imaging tumor hypoxia. Red light-emitting iridium complex Ir(btp)2(acac) (BTP) presented hypoxia-dependent light emission in culture cell lines, whose intensity was in parallel with hypoxia-inducible factor (HIF)-1 expression. BTP was further applied to imaging five nude mouse-transplanted tumors. All tumors presented a bright BTP-emitting image as early as 5 min after the injection. The BTP-dependent tumor image peaked at 1 to 2 h after the injection, and was then removed from tumors within 24 h. The minimal BTP image recognition size was at least 2 mm in diameter. By morphological examination and phosphorescence lifetime measurement, BTP is presumed to localize to the tumor cells, not to stay in the tumor microvessels by binding to albumin. The primary problem on suse of luminescent probe for tumor imaging is its weak penetrance to deep tissues from the skin surface. Since BTP is easily modifiable, we made BTP analogues with a longer excitation/emission wavelength to improve the tissue penetrance. One of them, BTPHSA, displayed 560/720 wavelength, and depicted its clear imaging from tumors transplanted over 6-7 mm deep from the skin surface. We suggest that BTP analogues have a vast potential for imaging hypoxic lesions such as tumor tissues.

  1. Assessment of intratumor hypoxia by integrated 18F-FDG PET / perfusion CT in a liver tumor model.

    Directory of Open Access Journals (Sweden)

    Yong Wang

    Full Text Available Hypoxia in solid tumors occurs when metabolic demands in tumor cells surpass the delivery of oxygenated blood. We hypothesize that the 18F-fluorodeoxyglucose (18F-FDG metabolism and tumor blood flow mismatch would correlate with tumor hypoxia.Liver perfusion computed tomography (CT and 18F-FDG positron emission tomography (PET imaging were performed in twelve rabbit livers implanted with VX2 carcinoma. Under CT guidance, a fiber optic probe was inserted into the tumor to measure the partial pressure of oxygen (pO2. Tumor blood flow (BF and standardized uptake value (SUV were measured to calculate flow-metabolism ratio (FMR. Tumor hypoxia was further identified using pimonidazole immunohistochemical staining. Pearson correlation analysis was performed to determine the correlation between the imaging parameters and pO2 and pimonidazole staining.Weak correlations were found between blood volume (BV and pO2 level (r = 0.425, P = 0.004, SUV and pO2 (r = -0.394, P = 0.007, FMR and pimonidazole staining score (r = -0.388, P = 0.031. However, there was stronger correlation between tumor FMR and pO2 level (r = 0.557, P < 0.001.FMR correlated with tumor oxygenation and pimonidazole staining suggesting it may be a potential hypoxic imaging marker in liver tumor.

  2. Intermittent hypoxia increases kidney tumor vascularization in a murine model of sleep apnea.

    Directory of Open Access Journals (Sweden)

    Antoni Vilaseca

    Full Text Available We investigate the effects of intermittent hypoxia (IH, a characteristic feature of obstructive sleep apnea (OSA, on renal cancer progression in an animal and cell model. An in vivo mouse model (Balb/c, n = 50 of kidney cancer was used to assess the effect of IH on tumor growth, metastatic capacity, angiogenesis and tumor immune response. An in vitro model tested the effect of IH on RENCA cells, macrophages and endothelial cells. Tumor growth, metastatic capacity, circulating vascular endothelial growth factor (VEGF and content of endothelial cells, tumor associated macrophages and their phenotype were assessed in the tumor. In vitro, VEGF cell expression was quantified.Although IH did not boost tumor growth, it significantly increased endothelial cells (p = 0.001 and circulating VEGF (p<0.001 in the in vivo model. Macrophages exposed to IH in vitro increased VEGF expression, whereas RENCA cells and endothelial cells did not. These findings are in keeping with previous clinical data suggesting that OSA has no effect on kidney cancer size and that the association observed between OSA and higher Fuhrman grade of renal cell carcinoma may be mediated though a proangiogenic process, with a key role of macrophages.

  3. Intermittent hypoxia increases kidney tumor vascularization in a murine model of sleep apnea.

    Science.gov (United States)

    Vilaseca, Antoni; Campillo, Noelia; Torres, Marta; Musquera, Mireia; Gozal, David; Montserrat, Josep M; Alcaraz, Antonio; Touijer, Karim A; Farré, Ramon; Almendros, Isaac

    2017-01-01

    We investigate the effects of intermittent hypoxia (IH), a characteristic feature of obstructive sleep apnea (OSA), on renal cancer progression in an animal and cell model. An in vivo mouse model (Balb/c, n = 50) of kidney cancer was used to assess the effect of IH on tumor growth, metastatic capacity, angiogenesis and tumor immune response. An in vitro model tested the effect of IH on RENCA cells, macrophages and endothelial cells. Tumor growth, metastatic capacity, circulating vascular endothelial growth factor (VEGF) and content of endothelial cells, tumor associated macrophages and their phenotype were assessed in the tumor. In vitro, VEGF cell expression was quantified.Although IH did not boost tumor growth, it significantly increased endothelial cells (p = 0.001) and circulating VEGF (p<0.001) in the in vivo model. Macrophages exposed to IH in vitro increased VEGF expression, whereas RENCA cells and endothelial cells did not. These findings are in keeping with previous clinical data suggesting that OSA has no effect on kidney cancer size and that the association observed between OSA and higher Fuhrman grade of renal cell carcinoma may be mediated though a proangiogenic process, with a key role of macrophages.

  4. Tumor hypoxia at the micro-regional level: clinical relevance and predictive value of exogenous and endogenous hypoxic cell markers

    International Nuclear Information System (INIS)

    Bussink, Johan; Kaanders, Johannes H.A.M.; Kogel, Albert J. van der

    2003-01-01

    Background and purpose: Tumor oxygenation is recognized as an important determinant of the outcome of radiotherapy and possibly also of other treatment modalities in a number of tumor types and in particular in squamous cell carcinomas. The hypoxic status of various solid tumors has been related to a poor prognosis due to tumor progression towards a more malignant phenotype, with increased metastatic potential, and an increased resistance to treatment. It has been demonstrated in head and neck cancer that hypoxic radioresistance can be successfully counteracted by hypoxia modifying approaches. The microregional distribution and the level of tumor hypoxia depend on oxygen consumption and temporal and spatial variations in blood supply. It is unclear if severely hypoxic cells can resume clonogenicity when O 2 and nutrients become available again as a result of (treatment related) changes in the tumor microenvironment. Non-terminally differentiated hypoxic cells that are capable of proliferation are important for outcome because of their resistance to radiotherapy and possibly other cytotoxic treatments. Various exogenous and endogenous markers for hypoxia are currently available and can be studied in relation to each other, the tumor architecture and the tumor microenvironment. Use of nitroimidazole markers with immunohistochemical detection allows studying tumor cell hypoxia at the microscopic level. Co-registration with other microenvironmental parameters, such as vascular architecture (vascular density), blood perfusion, tumor cell proliferation and apoptosis, offers the possibility to obtain a comprehensive functional image of tumor patho-physiology and to study the effects of different modalities of cancer treatment. Conclusion: A number of functional microregional parameters have emerged that are good candidates for future use as indicators of tumor aggressiveness and treatment response. The key question is whether these parameters can be used as tools for

  5. A RNA antagonist of hypoxia-inducible factor-1alpha, EZN-2968, inhibits tumor cell growth

    DEFF Research Database (Denmark)

    Greenberger, Lee M; Horak, Ivan D; Filpula, David

    2008-01-01

    Hypoxia-inducible factor-1 (HIF-1) is a transcription factor that plays a critical role in angiogenesis, survival, metastasis, drug resistance, and glucose metabolism. Elevated expression of the alpha-subunit of HIF-1 (HIF-1alpha), which occurs in response to hypoxia or activation of growth factor...... the expression of HIF-1alpha mRNA. In vitro, in human prostate (15PC3, PC3, and DU145) and glioblastoma (U373) cells, EZN-2968 induced a potent, selective, and durable antagonism of HIF-1 mRNA and protein expression (IC(50), 1-5 nmol/L) under normoxic and hypoxic conditions associated with inhibition of tumor......-regulation of endogenous HIF-1alpha and vascular endothelial growth factor in the liver. The effect can last for days after administration of single dose of EZN-2968 and is associated with long residence time of locked nucleic acid in certain tissues. In efficacy studies, tumor reduction was found in nude mice implanted...

  6. Intermittent hypoxia-induced changes in tumor-associated macrophages and tumor malignancy in a mouse model of sleep apnea.

    Science.gov (United States)

    Almendros, Isaac; Wang, Yang; Becker, Lev; Lennon, Frances E; Zheng, Jiamao; Coats, Brittney R; Schoenfelt, Kelly S; Carreras, Alba; Hakim, Fahed; Zhang, Shelley X; Farré, Ramon; Gozal, David

    2014-03-01

    An increased cancer aggressiveness and mortality have been recently reported among patients with obstructive sleep apnea (OSA). Intermittent hypoxia (IH), a hallmark of OSA, enhances melanoma growth and metastasis in mice. To assess whether OSA-related adverse cancer outcomes occur via IH-induced changes in host immune responses, namely tumor-associated macrophages (TAMs). Lung epithelial TC1 cell tumors were 84% greater in mice subjected to IH for 28 days compared with room air (RA). In addition, TAMs in IH-exposed tumors exhibited reductions in M1 polarity with a shift toward M2 protumoral phenotype. Although TAMs from tumors harvested from RA-exposed mice increased TC1 migration and extravasation, TAMs from IH-exposed mice markedly enhanced such effects and also promoted proliferative rates and invasiveness of TC1 cells. Proliferative rates of melanoma (B16F10) and TC1 cells exposed to IH either in single culture or in coculture with macrophages (RAW 264.7) increased only when RAW 264.7 macrophages were concurrently present. Our findings support the notion that IH-induced alterations in TAMs participate in the adverse cancer outcomes reported in OSA.

  7. Hypoxia marker labeling in tumor biopsies: quantification of labeling variation and criteria for biopsy sectioning

    International Nuclear Information System (INIS)

    Thrall, Donald E.; Rosner, Gary L.; Azuma, Chieko; McEntee, Margaret C.; Raleigh, James A.

    1997-01-01

    Background and purpose: The error associated with using biopsy-based methods for assessing parameters reflective of the tumor microenvironment depends on the variability in distribution of the parameter throughout the tumor and the biopsy sample. Some attention has been given to intratumoral distribution of parameters, but little attention has been given to their intrabiopsy distribution. We evaluated the intrabiopsy distribution of CCI-103F, a 2-nitroimidazole hypoxia marker. Materials and methods: The hypoxia marker CCI-103F was studied in dogs bearing spontaneous solid tumors. Two biopsies were taken from each of seven tumors, for a total of 14 biopsies. Biopsies were serially sectioned and four to six contiguous slides from each 100-150 μm of the biopsy were used to formulate the best estimate of CCI-103F labeled area throughout the biopsy sample. One, two or four slides were then randomly selected from each biopsy and the labeled area, based on this limited sample, was compared to the estimate obtained from counting all available slides. Random sampling of slides was repeated 1000 times for each biopsy sample. Results: CCI-103F labeling variance throughout the biopsy decreased as the estimated overall labeled area in the biopsy decreased. The error associated with estimating the overall labeled area in a biopsy from a randomly selected subset of slides decreased as the number of slides increased, and as the overall labeled area in the biopsy decreased. No minimally labeled biopsy was classified as unlabeled based on limited sampling. Conclusion: With regard to CCI-103F labeling, quantification of the labeled area in four randomly selected slides from a biopsy can provide, in most biopsies, an estimate of the labeled area in the biopsy within an absolute range of ±0.05

  8. Radiolabeled Probes Targeting Hypoxia-Inducible Factor-1-Active Tumor Microenvironments

    Directory of Open Access Journals (Sweden)

    Masashi Ueda

    2014-01-01

    Full Text Available Because tumor cells grow rapidly and randomly, hypoxic regions arise from the lack of oxygen supply in solid tumors. Hypoxic regions in tumors are known to be resistant to chemotherapy and radiotherapy. Hypoxia-inducible factor-1 (HIF-1 expressed in hypoxic regions regulates the expression of genes related to tumor growth, angiogenesis, metastasis, and therapy resistance. Thus, imaging of HIF-1-active regions in tumors is of great interest. HIF-1 activity is regulated by the expression and degradation of its α subunit (HIF-1α, which is degraded in the proteasome under normoxic conditions, but escapes degradation under hypoxic conditions, allowing it to activate transcription of HIF-1-target genes. Therefore, to image HIF-1-active regions, HIF-1-dependent reporter systems and injectable probes that are degraded in a manner similar to HIF-1α have been recently developed and used in preclinical studies. However, no probe currently used in clinical practice directly assesses HIF-1 activity. Whether the accumulation of 18F-FDG or 18F-FMISO can be utilized as an index of HIF-1 activity has been investigated in clinical studies. In this review, the current status of HIF-1 imaging in preclinical and clinical studies is discussed.

  9. Inhibition of hypoxia-inducible factor 1 with acriflavine sensitizes hypoxic tumor cells to photodynamic therapy with zinc phthalocyanine-encapsulating cationic liposomes

    NARCIS (Netherlands)

    Broekgaarden, Mans; Weijer, Ruud; Krekorian, Massis; van den IJssel, Bas; Kos, Milan; Alles, Lindy K.; van Wijk, Albert C.; Bikadi, Zsolt; Hazai, Eszter; van Gulik, Thomas M.; Heger, Michal

    2016-01-01

    Photodynamic therapy (PDT) is a tumor treatment modality in which a tumorlocalized photosensitizer is excited with light, which results in local production of reactive oxygen species, destruction of tumor vasculature, tumor hypoxia, tumor cell death, and induction of an anti-tumor immune response.

  10. Is 18F-FDG a surrogate tracer to measure tumor hypoxia? Comparison with the hypoxic tracer 14C-EF3 in animal tumor models

    International Nuclear Information System (INIS)

    Christian, Nicolas; Deheneffe, Stephanie; Bol, Anne; De Bast, Marc; Labar, Daniel; Lee, John A.; Gregoire, Vincent

    2010-01-01

    Introduction: Fluorodeoxyglucose (FDG) has been reported as a surrogate tracer to measure tumor hypoxia with positron emission tomography (PET). The hypothesis is that there is an increased uptake of FDG under hypoxic conditions secondary to enhanced glycolysis, compensating the hypoxia-induced loss of cellular energy production. Several studies have already addressed this issue, some with conflicting results. This study aimed to compare the tracers 14 C-EF3 and 18 F-FDG to detect hypoxia in mouse tumor models. Materials and methods: C3H, tumor-bearing mice (FSAII and SCCVII tumors) were injected iv with 14 C-EF3, and 1 h later with 18 F-FDG. Using a specifically designed immobilization device with fiducial markers, PET (Mosaic (registered) , Philips) images were acquired 1 h after the FDG injection. After imaging, the device containing mouse was frozen, transversally sliced and imaged with autoradiography (AR) (FLA-5100, Fujifilm) to obtain high resolution images of the 18 F-FDG distribution within the tumor area. After a 48-h delay allowing for 18 F decay a second AR was performed to image 14 C-EF3 distribution. AR images were aligned to reconstruct the full 3D tumor volume, and were compared with the PET images. Image segmentation with threshold-based methods was applied on both AR and PET images to derive various tracer activity volumes. The matching index DSI (dice similarity index) was then computed. The comparison was performed under normoxic (ambient air, FSAII: n = 4, SCCVII, n = 5) and under hypoxic conditions (10% O 2 breathing, SCCVII: n = 4). Results: On AR, under both ambient air and hypoxic conditions, there was a decreasing similarity between 14 C-EF3 and FDG with higher activity sub-volumes. Under normoxic conditions, when comparing the 10% of tumor voxels with the highest 18 F-FDG or 14 C-EF3 activity, a DSI of 0.24 and 0.20 was found for FSAII and SCCVII, respectively. Under hypoxic conditions, a DSI of 0.36 was observed for SCCVII tumors. When

  11. Azo-Based Iridium(III) Complexes as Multicolor Phosphorescent Probes to Detect Hypoxia in 3D Multicellular Tumor Spheroids.

    Science.gov (United States)

    Sun, Lingli; Li, Guanying; Chen, Xiang; Chen, Yu; Jin, Chengzhi; Ji, Liangnian; Chao, Hui

    2015-10-01

    Hypoxia is an important characteristic of malignant solid tumors and is considered as a possible causative factor for serious resistance to chemo- and radiotherapy. The exploration of novel fluorescent probes capable of detecting hypoxia in solid tumors will aid tumor diagnosis and treatment. In this study, we reported the design and synthesis of a series of "off-on" phosphorescence probes for hypoxia detection in adherent and three-dimensional multicellular spheroid models. All of the iridium(III) complexes incorporate an azo group as an azo-reductase reactive moiety to detect hypoxia. Reduction of non-phosphorescent probes Ir1-Ir8 by reductases under hypoxic conditions resulted in the generation of highly phosphorescent corresponding amines for detection of hypoxic regions. Moreover, these probes can penetrate into 3D multicellular spheroids over 100 μm and image the hypoxic regions. Most importantly, these probes display a high selectivity for the detection of hypoxia in 2D cells and 3D multicellular spheroids.

  12. Tumor circulating DNA profiling in xenografted mice exposed to intermittent hypoxia.

    Science.gov (United States)

    Cortese, Rene; Almendros, Isaac; Wang, Yang; Gozal, David

    2015-01-01

    Intermittent hypoxia (IH) a hallmark characteristic of obstructive sleep apnea (OSA), is proposed as a major determinant of processes involving tumor growth, invasion and metastasis. To examine whether circulating DNA (cirDNA) in blood plasma reflects changes in tumor cells under IH conditions, we used a xenografted murine model. Mice engrafted with TC1 epithelial lung cancer cells and controls were exposed to IH or room air (RA) conditions. Plasma cirDNA amounts were significantly increased in mice exposed to IH (p<0.05). Significant associations between plasma cirDNA concentrations and tumor size, weight and invasiveness also emerged (p<0.05). Using a methylation microarray-based approach, we identified 2,094 regions showing significant differential cirDNA modifications. Systems biology analyses revealed an association with molecular pathways deregulated in cancer progression and with distal and TSS-associated transcription factor binding sites. We detected clusters of highly variable regions in chromosomes 7, 13, 14 and X, which may highlight hotspots for DNA deletions. Single locus displayed high intragroup variation, suggesting cellular heterogeneity within the tissue may be associated to cirDNA release. Thus, exposures to IH increase the shedding of cirDNA into circulation, which carries epigenetic modifications that may characterize cell populations within the tumor that preferentially release their DNA upon IH exposure.

  13. Non-invasive pre-clinical MR imaging of prostate tumor hypoxia for radiation therapy prognosis

    Directory of Open Access Journals (Sweden)

    Derek White

    2014-03-01

    patient stratification for clinical implementation.------------------------------Cite this article as: White DA, Mason RP. Non-invasive pre-clinical MR imaging of prostate tumor hypoxia for radiation therapy prognosis. Int J Cancer Ther Oncol 2014; 2(2:020243. DOI: 10.14319/ijcto.0202.43

  14. Expression of hypoxia-inducible factor 1 alpha and its downstream targets in fibroepithelial tumors of the breast

    NARCIS (Netherlands)

    Kuijper, Arno; Groep, P. van der; Wall, E. van der; Diest, P.J. van

    2005-01-01

    INTRODUCTION Hypoxia-inducible factor 1 (HIF-1) alpha and its downstream targets carbonic anhydrase IX (CAIX) and vascular endothelial growth factor (VEGF) are key factors in the survival of proliferating tumor cells in a hypoxic microenvironment. We studied the expression and prognostic relevance

  15. EF5 PET of Tumor Hypoxia: A Predictive Imaging Biomarker of Response to Stereotactic Ablative Radiotherapy (SABR) for Early Lung Cancer

    Science.gov (United States)

    2017-11-01

    Figure 1 shows the tumor hypoxic fraction on EF5- PET imaging at baseline and after carbogen breathing. Figure 1: Effect of carbogen breathing...tumors (hypoxia) can compromise the effectiveness of radiation therapy, yet there is currently no clinically practical way to measure it. PET imaging...AWARD NUMBER: W81XWH-12-1-0236 TITLE: EF5 PET of Tumor Hypoxia: A Predictive Imaging Biomarker of Response to Stereotactic Ablative Radiotherapy

  16. Radiolabelling and evaluation of a novel sulfoxide as a PET imaging agent for tumor hypoxia

    International Nuclear Information System (INIS)

    Laurens, Evelyn; Yeoh, Shinn Dee; Rigopoulos, Angela; Cao, Diana; Cartwright, Glenn A.; O'Keefe, Graeme J.; Tochon-Danguy, Henri J.; White, Jonathan M.; Scott, Andrew M.; Ackermann, Uwe

    2014-01-01

    [ 18 F]FMISO is the most widely validated PET radiotracer for imaging hypoxic tissue. However, as a result of the pharmacokinetics of [ 18 F]FMISO a 2 h wait between tracer administration and patient scanning is required for optimal image acquisition. In order to develop hypoxia imaging agents with faster kinetics, we have synthesised and evaluated several F-18 labelled anilino sulfoxides. In this manuscript we report on the synthesis, in vitro and in vivo evaluation of a novel fluoroethyltriazolyl propargyl anilino sulfoxide. The radiolabelling of the novel tracer was achieved via 2-[ 18 F]fluoroethyl azide click chemistry. Radiochemical yields were 23 ± 4% based on 2-[ 18 F]fluoroethyl azide and 7 ± 2% based on K[ 18 F]F. The radiotracer did not undergo metabolism or defluorination in an in vitro assay using S9 liver fractions. Imaging studies using SK-RC-52 tumors in BALB/c nude mice have indicated that the tracer may have a higher pO 2 threshold than [ 18 F]FMISO for uptake in hypoxic tumors. Although clearance from muscle was faster than [ 18 F]FMISO, uptake in hypoxic tumors was slower. The average tumor to muscle ratio at 2 h post injection in large, hypoxic tumors with a volume greater than 686 mm 3 was 1.7, which was similar to the observed ratio of 1.75 for [ 18 F]FMISO. Although the new tracer showed improved pharmacokinetics when compared with the previously synthesised sulfoxides, further modifications to the chemical structure need to be made in order to offer significant in vivo imaging advantages over [ 18 F]FMISO

  17. [(68) Ga]-HP-DO3A-nitroimidazole: a promising agent for PET detection of tumor hypoxia.

    Science.gov (United States)

    Wu, Yunkou; Hao, Guiyang; Ramezani, Saleh; Saha, Debabrata; Zhao, Dawen; Sun, Xiankai; Sherry, A Dean

    2015-01-01

    The goal of this study is to evaluate a new (68) Ga-based imaging agent for detecting tumor hypoxia using positron emission tomography (PET). The new hypoxia targeting agent reported here, [(68) Ga]-HP-DO3A-nitroimidazole ([(68) Ga]-HP-DO3A-NI), was constructed by linking a nitroimidazole moiety with the macrocyclic ligand component of ProHance®, HP-DO3A. The hypoxia targeting capability of this agent was evaluated in A549 lung cancer cells in vitro and in SCID mice bearing subcutaneous A549 tumor xenografts. The cellular uptake assays showed that significantly more [(68) Ga]-HP-DO3A-NI accumulates in hypoxic tumor cells at 30, 60 and 120 min than in the same cells exposed to 21% O2 . The agent also accumulated in hypoxic tumors in vivo to give a tumor/muscle ratio (T/M) of 5.0 ± 1.2 (n = 3) as measured by PET at 2 h post-injection (p.i.). This was further confirmed by ex vivo biodistribution data. In addition, [(68) Ga]-HP-DO3A-NI displayed very favorable pharmacokinetic properties, as it was cleared largely through the kidneys with little to no accumulation in liver, heart or lung (%ID/g HP-DO3A, which lacks the nitroimidazole moiety, and by PET imaging of tumor-bearing mice breathing air versus 100% O2 . Given the commercial availability of cGMP (68) Ge/(68) Ga generators and the ease of (68) Ga labeling, the new agent could potentially be widely applied for imaging tumor hypoxia prior to radiation therapy. Copyright © 2015 John Wiley & Sons, Ltd.

  18. Increased hypoxia-inducible factor-1α in striated muscle of tumor-bearing mice.

    Science.gov (United States)

    Devine, Raymond D; Bicer, Sabahattin; Reiser, Peter J; Wold, Loren E

    2017-06-01

    Cancer cachexia is a progressive wasting disease resulting in significant effects on the quality of life and high mortality. Most studies on cancer cachexia have focused on skeletal muscle; however, the heart is now recognized as a major site of cachexia-related effects. To elucidate possible mechanisms, a proteomic study was performed on the left ventricles of colon-26 (C26) adenocarcinoma tumor-bearing mice. The results revealed several changes in proteins involved in metabolism. An integrated pathway analysis of the results revealed a common mediator in hypoxia-inducible factor-1α (HIF-1α). Work by other laboratories has shown that extensive metabolic restructuring in the C26 mouse model causes changes in gene expression that may be affected directly by HIF-1α, such as glucose metabolic genes. M-mode echocardiography showed progressive decline in heart function by day 19 , exhibited by significantly decreased ejection fraction and fractional shortening, along with posterior wall thickness. Using Western blot analysis, we confirmed that HIF-1α is significantly upregulated in the heart, whereas there were no changes in its regulatory proteins, prolyl hydroxylase domain-containing protein 2 (PHD2) and von Hippel-Lindau protein (VHL). PHD2 requires both oxygen and iron as cofactors for the hydroxylation of HIF-1α, marking it for ubiquination via VHL and subsequent destruction by the proteasome complex. We examined venous blood gas values in the tumor-bearing mice and found significantly lower oxygen concentration compared with control animals in the third week after tumor inoculation. We also examined select skeletal muscles to determine whether they are similarly affected. In the diaphragm, extensor digitorum longus, and soleus, we found significantly increased HIF-1α in tumor-bearing mice, indicating a hypoxic response, not only in the heart, but also in skeletal muscle. These results indicate that HIF-1α may contribute, in part, to the metabolic changes

  19. WE-FG-BRA-08: Potential Role of the Glycolytic Oscillator in Acute Hypoxia in Tumors

    International Nuclear Information System (INIS)

    Che Fru, L; Adamson, E; Campos, D; Song, C; Kimple, R; Fain, S; Kissick, M; Jacques, S; Kogel, A van der; Nickel, K

    2016-01-01

    Purpose: Oscillatory dynamics in acute hypoxia have been observed, but poorly understood. They have mostly been attributed to vascular perturbations, but no link has yet been made to metabolic causes. We set out to determine the fundamental frequencies and test for coherence in tumor oxygen dynamics and spatial properties. Methods: Severe combined immunodeficient (SCID) mice were inoculated onto bilateral flanks with human derived head and neck carcinoma (UW-SCC22) cell line xenografts. Oxygen dynamics were monitored in the tumor every minute for an hour using three modalities: blood oxygen level dependent - magnetic resonance imaging (BOLD-MRI), hemoglobin oxygen saturation photoacoustic, and locally manufactured optical probes for spectral fitting. A statistical test was used to separate fluctuating from non-fluctuating voxels and pixels in BOLD-MRI and photoacoustic data respectively. The power spectrum density (PSD) and the autocorrelation functions were calculated for the time series of each voxel, pixel and region, of the BOLD-MRI, photoacoustic or fiber optic data respectively. Results: Using all three techniques, intermittent oxygen dynamics with both coherent and incoherent signatures was observed in the tumors. Upon averaging the PSDs of fluctuating voxels and pixels, it was found that these oscillations occurred with periods of minutes to tens of minutes from all three approaches. Observations from the BOLD-MRI and photoacoustic data showed that clusters of voxels oscillated in a synchronized manner. Conclusion: We were able to use three different modalities to show that fluctuation in tumor oxygen is both coherent and incoherent, with periods of minutes to tens of minutes. These periods are very similar to those from the well-established metabolic, non-linear biomechanical phenomenon called the glycolytic oscillator. This may provide an additional explanation to the cause of cyclic hypoxia. Such dynamics could have profound implications in

  20. Targeting Hypoxia-Inducible Factor 1α in a New Orthotopic Model of Glioblastoma Recapitulating the Hypoxic Tumor Microenvironment.

    Science.gov (United States)

    Nigim, Fares; Cavanaugh, Jill; Patel, Anoop P; Curry, William T; Esaki, Shin-ichi; Kasper, Ekkehard M; Chi, Andrew S; Louis, David N; Martuza, Robert L; Rabkin, Samuel D; Wakimoto, Hiroaki

    2015-07-01

    Tissue hypoxia and necrosis represent pathophysiologic and histologic hallmarks of glioblastoma (GBM). Although hypoxia inducible factor 1α (HIF-1α) plays crucial roles in the malignant phenotypes of GBM, developing HIF-1α-targeted agents has been hampered by the lack of a suitable preclinical model that recapitulates the complex biology of clinical GBM. We present a new GBM model, MGG123, which was established from a recurrent human GBM. Orthotopic xenografting of stem-like MGG123 cells reproducibly generated lethal tumors that were characterized by foci of palisading necrosis, hypervascularity, and robust stem cell marker expression. Perinecrotic neoplastic cells distinctively express HIF-1α and are proliferative in both xenografts and the patient tissue. The xenografts contain scattered hypoxic foci that were consistently greater than 50 μm distant from blood vessels, indicating intratumoral heterogeneity of oxygenation. Hypoxia enhanced HIF-1α expression in cultured MGG123 cells, which was abrogated by the HIF-1α inhibitors digoxin or ouabain. In vivo, treatment of orthotopic MGG123 xenografts with digoxin decreased HIF-1α expression, vascular endothelial growth factor mRNA levels, and CD34-positive vasculature within the tumors, and extended survival of mice bearing the aggressive MGG123 GBM. This preclinical tumor model faithfully recapitulates the GBM-relevant hypoxic microenvironment and stemness and is a suitable platform for studying disease biology and developing hypoxia-targeted agents.

  1. Au@Pt nanoparticles as catalase mimics to attenuate tumor hypoxia and enhance immune cell-mediated cytotoxicity

    Science.gov (United States)

    Liang, Hong; Wu, Ying; Ou, Xiang-Yu; Li, Jing-Ying; Li, Juan

    2017-11-01

    Hypoxic tumor microenvironment (TME) is closely linked to tumor progression, heterogeneity and immune suppression. Therefore, the development of effective methods to overcome hypoxia and substantially enhance the immunotherapy efficacy remains a desirable goal. Herein, we engineered a biocompatible Au core/Pt shell nanoparticles (Au@Pt NPs) to reoxygenate the TME by reacting with endogenous H2O2. Treatment with Au@Pt NPs appeared to improve oxygen in intracellular environments and decrease hypoxia-inducible factor-1α expression. Furthermore, the integration of high catalytic efficiency of Au@Pt NPs with cytokine-induced killer (CIK) cell immunotherapy, could lead to significantly improve the effect of CIK cell-mediated cytotoxicity. These results suggest great potential of Au@Pt NPs for regulation of the hypoxic TME and enhance immune cell mediated anti-tumor immunity.

  2. Synthesis and biodistribution of a novel 99mTc-DMSA-metronidazole ester as a potential tumor hypoxia imaging agent

    International Nuclear Information System (INIS)

    Junbo Zhang; Jinfeng Huo; Yan Pang; Sheng Yang; Yining He; Tingting Tang; Chenchen Yang; Xuebin Wang

    2010-01-01

    The dimercaptosuccinic acid metronidazole ester (DMSAMe) was synthesized and radiolabeled with 99m Tc to form the 99m Tc-DMSAMe complex in high yield. The radiochemical purity of the 99m Tc-DMSAMe complex was over 90%, as measured by TLC and by HPLC, without any notable decomposition at room temperature over a period of 6 h. Its partition coefficient indicated that it was a lipophilic complex. The tumor cell experiment and the biodistribution in mice bearing S 180 tumor showed that the 99m Tc-DMSAMe complex had a certain hypoxic selectivity and accumulated in the tumor with high uptake and good retention. The tumor/blood and tumor/muscle ratios increased with time, suggesting it would be a possible tumor hypoxia imaging agent. (author)

  3. Catalase-loaded cisplatin-prodrug-constructed liposomes to overcome tumor hypoxia for enhanced chemo-radiotherapy of cancer.

    Science.gov (United States)

    Zhang, Rui; Song, Xuejiao; Liang, Chao; Yi, Xuan; Song, Guosheng; Chao, Yu; Yang, Yu; Yang, Kai; Feng, Liangzhu; Liu, Zhuang

    2017-09-01

    Aiming at improved therapeutic efficacies, the combination of chemotherapy and radiotherapy (chemo-radiotherapy) has been widely studied and applied in clinic. However, the hostile characteristics of tumor microenvironment such as hypoxia often limit the efficacies in both types of cancer therapies. Herein, catalase (CAT), an antioxidant enzyme, is encapsulated inside liposomes constituted by cisplatin (IV)-prodrug-conjugated phospholipid, forming CAT@Pt (IV)-liposome for enhanced chemo-radiotherapy of cancer. After being loaded inside liposomes, CAT within CAT@Pt (IV)-liposome shows retained and well-protected enzyme activity, and is able to trigger decomposition of H 2 O 2 produced by tumor cells, so as to produce additional oxygen for hypoxia relief. As the result, treatment of CAT@Pt (IV)-liposome induces the highest level of DNA damage in cancer cells after X-ray radiation compared to the control groups. In vivo tumor treatment further demonstrates a remarkably improved therapeutic outcome in chemo-radiotherapy with such CAT@Pt (IV)-liposome nanoparticles. Hence, an exquisite type of liposome-based nanoparticles is developed in this work by integrating cisplatin-based chemotherapy and catalase-induced tumor hypoxia relief together for combined chemo-radiotherapy with great synergistic efficacy, promising for clinical translation in cancer treatment. Copyright © 2017. Published by Elsevier Ltd.

  4. Sorafenib Increases Tumor Hypoxia in Cervical Cancer Patients Treated With Radiation Therapy: Results of a Phase 1 Clinical Study

    Energy Technology Data Exchange (ETDEWEB)

    Milosevic, Michael F., E-mail: mike.milosevic@rmp.uhn.ca [Radiation Medicine Program, Princess Margaret Cancer Center, University Health Network, Toronto (Canada); Department of Radiation Oncology, University of Toronto, Toronto (Canada); Townsley, Carol A. [Department of Medical Oncology, Princess Margaret Cancer Center, University Health Network, Toronto (Canada); Chaudary, Naz [Department of Advanced Molecular Oncology, Princess Margaret Cancer Center, University Health Network, Toronto (Canada); Clarke, Blaise [Department of Pathology, Princess Margaret Cancer Center, University Health Network, Toronto (Canada); Department of Laboratory Medicine and Pathology, University of Toronto, Toronto (Canada); Pintilie, Melania [Department of Clinical Study Coordination and Biostatistics, Princess Margaret Cancer Center, University Health Network, Toronto (Canada); Fan, Stacy; Glicksman, Rachel [Radiation Medicine Program, Princess Margaret Cancer Center, University Health Network, Toronto (Canada); Haider, Masoom [Department of Medical Imaging, Sunnybrook Health Sciences Centre, Toronto (Canada); Department of Medical Imaging, University of Toronto, Toronto (Canada); Kim, Sunmo [Radiation Medicine Program, Princess Margaret Cancer Center, University Health Network, Toronto (Canada); MacKay, Helen [Department of Medical Oncology, Princess Margaret Cancer Center, University Health Network, Toronto (Canada); Department of Medicine, University of Toronto, Toronto (Canada); Yeung, Ivan [Radiation Medicine Program, Princess Margaret Cancer Center, University Health Network, Toronto (Canada); Department of Radiation Oncology, University of Toronto, Toronto (Canada); Hill, Richard P. [Department of Radiation Oncology, University of Toronto, Toronto (Canada); Department of Advanced Molecular Oncology, Princess Margaret Cancer Center, University Health Network, Toronto (Canada); Department of Medical Biophysics, University of Toronto, Toronto (Canada); and others

    2016-01-01

    Purpose: Preclinical studies have shown that angiogenesis inhibition can improve response to radiation therapy (RT). The purpose of this phase 1 study was to examine the angiogenesis inhibitor sorafenib in patients with cervical cancer receiving radical RT and concurrent cisplatin (RTCT). Methods and Materials: Thirteen patients with stage IB to IIIB cervical cancer participated. Sorafenib was administered daily for 7 days before the start of standard RTCT in patients with early-stage, low-risk disease and also during RTCT in patients with high-risk disease. Biomarkers of tumor vascularity, perfusion, and hypoxia were measured at baseline and again after 7 days of sorafenib alone before the start of RTCT. The median follow-up time was 4.5 years. Results: Initial complete response was seen in 12 patients. One patient died without achieving disease control, and 4 experienced recurrent disease. One patient with an extensive, infiltrative tumor experienced pelvic fistulas during treatment. The 4-year actuarial survival was 85%. Late grade 3 gastrointestinal toxicity developed in 4 patients. Sorafenib alone produced a reduction in tumor perfusion/permeability and an increase in hypoxia, which resulted in early closure of the study. Conclusions: Sorafenib increased tumor hypoxia, raising concern that it might impair rather than improve disease control when added to RTCT.

  5. Low-field magnetic resonance imaging to visualize chronic and cycling hypoxia in tumor-bearing mice.

    Science.gov (United States)

    Yasui, Hironobu; Matsumoto, Shingo; Devasahayam, Nallathamby; Munasinghe, Jeeva P; Choudhuri, Rajani; Saito, Keita; Subramanian, Sankaran; Mitchell, James B; Krishna, Murali C

    2010-08-15

    Tumors exhibit fluctuations in blood flow that influence oxygen concentrations and therapeutic resistance. To assist therapeutic planning and improve prognosis, noninvasive dynamic imaging of spatial and temporal variations in oxygen partial pressure (pO(2)) would be useful. Here, we illustrate the use of pulsed electron paramagnetic resonance imaging (EPRI) as a novel imaging method to directly monitor fluctuations in oxygen concentrations in mouse models. A common resonator platform for both EPRI and magnetic resonance imaging (MRI) provided pO(2) maps with anatomic guidance and microvessel density. Oxygen images acquired every 3 minutes for a total of 30 minutes in two different tumor types revealed that fluctuation patterns in pO(2) are dependent on tumor size and tumor type. The magnitude of fluctuations in pO(2) in SCCVII tumors ranged between 2- to 18-fold, whereas the fluctuations in HT29 xenografts were of lower magnitude. Alternating breathing cycles with air or carbogen (95% O(2) plus 5% CO(2)) distinguished higher and lower sensitivity regions, which responded to carbogen, corresponding to cycling hypoxia and chronic hypoxia, respectively. Immunohistochemical analysis suggests that the fluctuation in pO(2) correlated with pericyte density rather than vascular density in the tumor. This EPRI technique, combined with MRI, may offer a powerful clinical tool to noninvasively detect variable oxygenation in tumors. (c)2010 AACR.

  6. Identification of longitudinal tissue pO2 gradients as one cause for vascular hypoxia in window chamber tumors

    International Nuclear Information System (INIS)

    Dewhirst, Mark W.; Ong, Edgardo T.; Braun, Rod D.; Evans, Sydney M.; Wilson, David

    1997-01-01

    Purpose: We have previously found that vascular hypoxia exists in tumors, even in vessels with active blood flow. We have also reported that the arteriolar input seems to be constrained to entry into the tumor in one surface of the tissue and that the pO2 of tumor arterioles is lower than in comparable arterioles of normal tissues. Both of these features contribute to lowered intravascular pO2 and tissue hypoxia. In this report, we investigated the hypothesis that the anatomical constraint of arteriolar supply from one side of the tumor will lead to longitudinal tissue gradients in pO2 (i.e. the farther removed one is from the arteriolar source, the more hypoxic the vasculature will be). Materials and Methods: Fischer-344 rats had dorsal flap window chambers implanted in the skin fold with simultaneous transplantation of the R3230AC tumor. Tumors were studied at 9-10 days post transplantation, at a diameter of 3-4mm; the tissue thickness was 200μm. For magnetic resonance microscopic imaging, 1.0ml of GdDTPA-BSA complex was injected i.v. into rats bearing window chamber tumors; the upper glass window was removed, and a suffusion medium of balanced salt solution added in its place, prior to injection of the contrast agent. After 15s the skin flap was immersed in 10% formalin and then removed from the animal. The sample was imaged at 9.4T, using spin warp encoding (TR=200ms, TE=6ms) and fourier transformation of the scanning data. The resultant images had a voxel size of 40μm 3 . Phosphorescence quench imaging (PQI) was used to measure vascular pO2 following i.v. administration of 3.5mg Pd-mesotetra-(4-carboxyphenyl) porphyrin. Blue and green light excitations of the upper and lower surfaces of window chambers were made (penetration depth of light ∼ 50 vs >200μm, respectively). Results: In prior studies we demonstrated that arteriolar input into window chamber tumors appeared to be constrained to the fascial surface upon which the tumor grows. 3-D magnetic

  7. 31P nuclear magnetic resonance spectroscopy studies of tumor energy metabolism and its relationship to intracapillary oxyhemoglobin saturation status and tumor hypoxia.

    Science.gov (United States)

    Rofstad, E K; DeMuth, P; Fenton, B M; Sutherland, R M

    1988-10-01

    Relationships between tumor bioenergetic status on the one hand and intracapillary oxyhemoglobin (HbO2) saturation status and fraction of radiobiologically hypoxic cells on the other were studied using two murine sarcoma lines (KHT, RIF-1) and two human ovarian carcinoma xenograft lines (MLS, OWI). Tumor energy metabolism was studied in vivo by 31P nuclear magnetic resonance (NMR) spectroscopy and the resonance area ratio (PCr + NTP beta)/Pi was used as parameter for bioenergetic status. Intracapillary HbO2 saturation status reflects the oxygen supply conditions in tumors and was measured in vitro using a cryospectrophotometric method. The KHT, RIF-1, and MLS lines showed decreasing bioenergetic status, i.e., decreasing PCr and NTP beta resonances and an increasing Pi resonance, with increasing tumor volume, whereas the OWI line showed no changes in these resonances during tumor growth. The volume-dependence of the HbO2 saturation status differed similarly among the tumor lines; HbO2 saturation status decreased with increasing tumor volume for the KHT, RIF-1, and MLS lines and was independent of tumor volume for the OWI line. Moreover, linear correlations were found between bioenergetic status and HbO2 saturation status for individual tumors of the KHT, RIF-1, and MLS lines. These observations together indicated a direct relationship between 31P-NMR spectral parameters and tumor oxygen supply conditions. However, this relationship was not identical for the different tumor lines, suggesting that it was influenced by intrinsic properties of the tumor cells such as rate of respiration and ability to survive under hypoxia. Similarly, there was no correlation between bioenergetic status and fraction of radiobiologically hypoxic cells across the four tumor lines. This indicates that 31P-NMR spectroscopy data have to be supplemented with other data, e.g., rate of oxygen consumption, cell survival time under hypoxic stress, and/or fraction of metabolically active

  8. Noninvasive Multimodality Imaging of the Tumor Microenvironment: Registered Dynamic Magnetic Resonance Imaging and Positron Emission Tomography Studies of a Preclinical Tumor Model of Tumor Hypoxia

    Directory of Open Access Journals (Sweden)

    HyungJoon Cho

    2009-03-01

    Full Text Available In vivo knowledge of the spatial distribution of viable, necrotic, and hypoxic areas can provide prognostic information about the risk of developing metastases and regional radiation sensitivity and may be used potentially for localized dose escalation in radiation treatment. In this study, multimodality in vivo magnetic resonance imaging (MRI and positron emission tomography (PET imaging using stereotactic fiduciary markers in the Dunning R3327AT prostate tumor were performed, focusing on the relationship between dynamic contrast-enhanced (DCE MRI using Magnevist (Gd-DTPA and dynamic 18F-fluoromisonidazole (18F-Fmiso PET. The noninvasive measurements were verified using tumor tissue sections stained for hematoxylin/eosin and pimonidazole. To further validate the relationship between 18F-Fmiso and pimonidazole uptake, 18F digital autoradiography was performed on a selected tumor and compared with the corresponding pimonidazole-stained slices. The comparison of Akep values (kep = rate constant of movement of Gd-DTPA between the interstitial space and plasma and A = amplitude in the two-compartment model (Hoffmann U, Brix G, Knopp MV, Hess T and Lorenz WJ (1995. Magn Reson Med 33, 506– 514 derived from DCE-MRI studies and from early 18F-Fmiso uptake PET studies showed that tumor vasculature is a major determinant of early 18F-Fmiso uptake. A negative correlation between the spatial map of Akep and the slope map of late (last 1 hour of the dynamic PET scan 18F-Fmiso uptake was observed. The relationships between DCE-MRI and hematoxylin/eosin slices and between 18F-Fmiso PET and pimonidazole slices confirm the validity of MRI/PET measurements to image the tumor microenvironment and to identify regions of tumor necrosis, hypoxia, and well-perfused tissue.

  9. Detection of hypoxia in microscopic tumors using 131I-labeled iodo-azomycin galactopyranoside (131I-IAZGP) digital autoradiography

    International Nuclear Information System (INIS)

    Li, Xiao-Feng; Sun, Xiaorong; Ma, Yuanyuan; Suehiro, Makiko; Zhang, Mutian; Russell, James; Humm, John L.; Ling, C.C.; O'Donoghue, Joseph A.

    2010-01-01

    Previous studies have shown that tumors less than 1 mm diameter derived from HT29 colorectal cancer cells are extremely hypoxic when grown intraperitoneally or intradermally in nude mice, whereas those of greater size (approximately 1-4 mm diameter) are not significantly hypoxic. The object of this study was to determine if digital autoradiography using the radiolabeled hypoxia imaging tracer iodo-azomycin galactopyranoside ( 131 I-IAZGP) could detect hypoxia in this model. Microscopic HT29 tumors were grown as disseminated peritoneal disease and intradermally in nude mice. Tumors ranged in size from a few hundred microns to several millimeters in diameter. Animals were intravenously administered 131 I-IAZGP and pimonidazole 2 h before sacrifice. Following sacrifice, the intratumoral distribution of 131 I-IAZGP was assessed by digital autoradiography and compared with immunofluorescence microscopic images of pimonidazole binding and carbonic anhydrase IX (CAIX) expression. The distributions of 131 I-IAZGP, pimonidazole, and CAIX expression were similar. Tumors less than 1 mm diameter displayed high 131 I-IAZGP uptake; these tumors also stained strongly for pimonidazole and CAIX. Larger tumors (approximately 1-4 mm diameter) were not significantly hypoxic and had low 131 I-IAZGP accumulation. 131 I-IAZGP can detect hypoxia in microscopic tumors. Microscopic tumors are useful models for the validation of hypoxia radiotracers, and digital autoradiography is an appropriate technique for studying the distribution of hypoxia radiotracers in microscopic tumors. (orig.)

  10. 31P NMR spectroscopy and HbO2 cryospectrophotometry in prediction of tumor radioresistance caused by hypoxia.

    Science.gov (United States)

    Rofstad, E K; DeMuth, P; Fenton, B M; Ceckler, T L; Sutherland, R M

    1989-04-01

    The aim of this study was to search for possible relationships between the fraction of radiobiologically hypoxic cells in tumors and their 31P NMR spectral parameters and intracapillary HbO2 saturations. Four different tumor lines, two murine sarcomas (KHT, RIF-1) and two human ovarian carcinoma xenografts (MLS, OWI), were used. When tumor volume increased from about 200 mm3 to about 2000 mm3, hypoxic fraction increased from 12 to 23% for the KHT line, from 0.9 to 1.7% for the RIF-1 line, and from 9 to 28% for the MLS line. The OWI line showed similar hypoxic fractions at 200 (17%) and 2000 mm3 (15%). Tumor bioenergetic status decreased, that is, the inorganic phosphate (Pi) resonance increased and the phosphocreatine (PCr) and nucleoside triphosphate beta (NTP beta) resonances decreased, with increasing tumor volume for the KHT, RIF-1, and MLS lines, whereas the OWI line did not show any changes in the 31P NMR spectral parameters during tumor growth. Similarly, tumor HbO2 saturation status, that is, the fraction of vessels with HbO2 saturation above 30%, decreased with increasing tumor volume for the KHT, RIF-1, and MLS lines, but remained unchanged during tumor growth for the OWI line. Although the data indicated a relationship between hypoxic fraction and tumor bioenergetic status as well as tumor HbO2 saturation status within a specific line during tumor growth, there was no correlation between hypoxic fraction and tumor bioenergetic status or tumor HbO2 saturation status across the four tumor lines. This may have occurred because cell survival time under hypoxic stress as well as fraction of non-clonogenic, but metabolically active hypoxic cells differed among the tumor lines. This indicates that 31P NMR spectroscopy and HbO2 cryospectrophotometry data have to be supplemented with other data to be useful in prediction of tumor radioresistance caused by hypoxia.

  11. Inflammatory cytokine tumor necrosis factor α suppresses neuroprotective endogenous erythropoietin from astrocytes mediated by hypoxia-inducible factor-2α.

    Science.gov (United States)

    Nagaya, Yoshiaki; Aoyama, Mineyoshi; Tamura, Tetsuya; Kakita, Hiroki; Kato, Shin; Hida, Hideki; Saitoh, Shinji; Asai, Kiyofumi

    2014-12-01

    Interest in erythropoietin (EPO) as a neuroprotective mediator has grown since it was found that systemically administered EPO is protective in several animal models of disease. However, given that the blood-brain barrier limits EPO entry into the brain, alternative approaches that induce endogenous EPO production in the brain may be more effective clinically and associated with fewer untoward side-effects. Astrocytes are the main source of EPO in the central nervous system. In the present study we investigated the effect of the inflammatory cytokine tumor necrosis factor α (TNFα) on hypoxia-induced upregulation of EPO in rat brain. Hypoxia significantly increased EPO mRNA expression in the brain and kidney, and this increase was suppressed by TNFα in vivo. In cultured astrocytes exposed to hypoxic conditions for 6 and 12 h, TNFα suppressed the hypoxia-induced increase in EPO mRNA expression in a concentration-dependent manner. TNFα inhibition of hypoxia-induced EPO expression was mediated primarily by hypoxia-inducible factor (HIF)-2α rather than HIF-1α. The effects of TNFα in reducing hypoxia-induced upregulation of EPO mRNA expression probably involve destabilization of HIF-2α, which is regulated by the nuclear factor (NF)-κB signaling pathway. TNFα treatment attenuated the protective effects of astrocytes on neurons under hypoxic conditions via EPO signaling. The effective blockade of TNFα signaling may contribute to the maintenance of the neuroprotective effects of EPO even under hypoxic conditions with an inflammatory response. © 2014 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  12. Hypoxia-inducible factor 1 alpha expression increases during colorectal carcinogenesis and tumor progression

    International Nuclear Information System (INIS)

    Simiantonaki, Nektaria; Taxeidis, Marios; Jayasinghe, Caren; Kurzik-Dumke, Ursula; Kirkpatrick, Charles James

    2008-01-01

    Hypoxia-inducible factor 1 alpha (HIF-1α) is involved in processes promoting carcinogenesis of many tumors. However, its role in the development of colorectal cancer is unknown. To investigate the significance of HIF-1α during colorectal carcinogenesis and progression we examined its expression in precursor lesions constituting the conventional and serrated pathways, as well as in non-metastatic and metastatic adenocarcinomas. Immunohistochemistry and Western blot is used to analyse HIF-1α expression in normal colonic mucosa, hyperplastic polyps (HPP), sessile serrated adenomas (SSA), low-grade (TA-LGD) and high-grade (TA-HGD) traditional adenomas as well as in non-metastatic and metastatic colorectal adenocarcinomas. Eight colorectal carcinoma cell lines are tested for their HIF-1α inducibility after lipopolysaccharide (LPS) stimulation using western blot and immunocytochemistry. In normal mucosa, HPP and TA-LGD HIF-1α was not expressed. In contast, perinuclear protein accumulation and nuclear expression of HIF-1α were shown in half of the examined SSA and TA-HGD. In all investigated colorectal carcinomas a significant nuclear HIF-1α overexpression compared to the premalignant lesions was observed but a significant correlation with the metastatic status was not found. Nuclear HIF-1α expression was strongly accumulated in perinecrotic regions. In these cases HIF-1α activation was seen in viable cohesive tumor epithelia surrounding necrosis and in dissociated tumor cells, which subsequently die. Enhanced distribution of HIF-1α was also seen in periiflammatory regions. In additional in vitro studies, treatment of diverse colorectal carcinoma cell lines with the potent pro-inflammatory factor lipopolysaccharide (LPS) led to HIF-1α expression and nuclear translocation. We conclude that HIF-1α expression occurs in early stages of colorectal carcinogenesis and achieves a maximum in the invasive stage independent of the metastatic status. Perinecrotic

  13. Evaluation of a compartmental model for estimating tumor hypoxia via FMISO dynamic PET imaging

    International Nuclear Information System (INIS)

    Wang Wenli; Nehmeh, Sadek A; O'Donoghue, Joseph; Zanzonico, Pat B; Schmidtlein, C Ross; Lee, Nancy Y; Humm, John L; Georgi, Jens-Christoph; Paulus, Timo; Narayanan, Manoj; Bal, Matthieu

    2009-01-01

    This paper systematically evaluates a pharmacokinetic compartmental model for identifying tumor hypoxia using dynamic positron emission tomography (PET) imaging with 18 F-fluoromisonidazole (FMISO). A generic irreversible one-plasma two-tissue compartmental model was used. A dynamic PET image dataset was simulated with three tumor regions-normoxic, hypoxic and necrotic-embedded in a normal-tissue background, and with an image-based arterial input function. Each voxelized tissue's time activity curve (TAC) was simulated with typical values of kinetic parameters, as deduced from FMISO-PET data from nine head-and-neck cancer patients. The dynamic dataset was first produced without any statistical noise to ensure that correct kinetic parameters were reproducible. Next, to investigate the stability of kinetic parameter estimation in the presence of noise, 1000 noisy samples of the dynamic dataset were generated, from which 1000 noisy estimates of kinetic parameters were calculated and used to estimate the sample mean and covariance matrix. It is found that a more peaked input function gave less variation in various kinetic parameters, and the variation of kinetic parameters could also be reduced by two region-of-interest averaging techniques. To further investigate how bias in the arterial input function affected the kinetic parameter estimation, a shift error was introduced in the peak amplitude and peak location of the input TAC, and the bias of various kinetic parameters calculated. In summary, mathematical phantom studies have been used to determine the statistical accuracy and precision of model-based kinetic analysis, which helps to validate this analysis and provides guidance in planning clinical dynamic FMISO-PET studies.

  14. Adipose tissue macrophage polarization by intermittent hypoxia in a mouse model of OSA: effect of tumor microenvironment.

    Science.gov (United States)

    Almendros, Isaac; Gileles-Hillel, Alex; Khalyfa, Abdelnaby; Wang, Yang; Zhang, Shelley X; Carreras, Alba; Farré, Ramon; Gozal, David

    2015-06-01

    Intermittent hypoxia (IH)-induces alterations in tumor-associated macrophages (TAMs) that are associated with adverse cancer outcomes, as reported in patients suffering from sleep apnea. Adipose tissues (AT) and bone-marrow (BM)-derived cells are the inferred sources of macrophages infiltrating malignant tumors. Here, the sources of TAMs and the phenotypic changes induced by IH in the ipsilateral and contralateral AT were investigated by using a syngeneic murine solid tumor model (TC1). C57/B6 male mice were exposed to either IH or room air (RA) for 6 weeks, with TC1 cells being inoculated in the 2nd week. Macrophage content, phenotype and tissue origin were assessed in tumors, and ipsilateral and contralateral AT. IH induced a ~2.2-fold increase in TAM tumor infiltration. However, differential responses in the tumor ipsilateral and contralateral AT emerged: IH increased infiltration of preferentially M1 macrophages in contralateral AT, while reductions in macrophages emerged in ipsilateral AT and primarily consisted of the M2 phenotype. These changes were accompanied by reciprocal increases in resident and BM-derived TAMs in the tumor. IH-induced phenotypic alterations in AT macrophages surrounding the tumor and their increased infiltration within the tumor may contribute to the accelerated tumor progression associated with IH. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  15. Tumor Hypoxia is Independent of Hemoglobin and Prognostic for Loco-regional Tumor Control after Primary Radiotherapy in Advanced Head and Neck Cancer

    International Nuclear Information System (INIS)

    Nordsmark, Marianne; Overgaard, Jens

    2004-01-01

    There is evidence that tumor hypoxia adversely affects loco-regional tumor control and survival in head and neck cancer. The aim of the current study was to compare pretreatment tumor oxygenation measured by Eppendorf pO2 electrodes with known prognostic factors in advanced head and neck tumors after definitive radiotherapy, and to evaluate the prognostic significance of these parameters on loco-regional tumor control. Sixty-seven patients, median age 56 years (22-82), all with primary stage III-IV squamous cell carcinoma were available for survival analysis. Tumor oxygenation was described as the fraction of pO2 values=2.5 mmHg (HP2.5) and the median tumor pO2. By regression analysis HP2.5 was independent of known prognostic factors including stage, pretreatment hemoglobin (Hb) and the largest tumor diameter at the site of pO2 measurement. By Kaplan-Meier analysis loco-regional tumor control at 5 years was in favor of less hypoxic tumors using either HP2.5 or median tumor pO2 as descriptors and stratifying by the median values. Also, Hb was prognostic of loco-regional tumor control at 5 years using the median value as cut off. HP2.5 as continuous parameter was highly significant for loco-regional tumor control in a multivariate analysis. In conclusion both HP2.5 and total Hb were prognostic for loco-regional tumor control, but HP2.5 as continuous variable was independently the strongest prognostic indicator for loco-regional tumor control after definitive primary radiotherapy in advanced head and neck tumors

  16. Erythrocyte-Membrane-Enveloped Perfluorocarbon as Nanoscale Artificial Red Blood Cells to Relieve Tumor Hypoxia and Enhance Cancer Radiotherapy.

    Science.gov (United States)

    Gao, Min; Liang, Chao; Song, Xuejiao; Chen, Qian; Jin, Qiutong; Wang, Chao; Liu, Zhuang

    2017-09-01

    Hypoxia, a common feature within many types of solid tumors, is known to be closely associated with limited efficacy for cancer therapies, including radiotherapy (RT) in which oxygen is essential to promote radiation-induced cell damage. Here, an artificial nanoscale red-blood-cell system is designed by encapsulating perfluorocarbon (PFC), a commonly used artificial blood substitute, within biocompatible poly(d,l-lactide-co-glycolide) (PLGA), obtaining PFC@PLGA nanoparticles, which are further coated with a red-blood-cell membrane (RBCM). The developed PFC@PLGA-RBCM nanoparticles with the PFC core show rather efficient loading of oxygen, as well as greatly prolonged blood circulation time owing to the coating of RBCM. With significantly improved extravascular diffusion within the tumor mass, owing to their much smaller nanoscale sizes compared to native RBCs with micrometer sizes, PFC@PLGA-RBCM nanoparticles are able to effectively deliver oxygen into tumors after intravenous injection, leading to greatly relieved tumor hypoxia and thus remarkably enhanced treatment efficacy during RT. This work thus presents a unique type of nanoscale RBC mimic for efficient oxygen delivery into solid tumors, favorable for cancer treatment by RT, and potentially other types of therapy as well. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. WE-AB-202-10: Modelling Individual Tumor-Specific Control Probability for Hypoxia in Rectal Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Warren, S; Warren, DR; Wilson, JM; Muirhead, R; Hawkins, MA; Maughan, T; Partridge, M [University of Oxford, Oxford, Oxfordshire (United Kingdom)

    2016-06-15

    Purpose: To investigate hypoxia-guided dose-boosting for increased tumour control and improved normal tissue sparing using FMISO-PET images Methods: Individual tumor-specific control probability (iTSCP) was calculated using a modified linear-quadratic model with rectal-specific radiosensitivity parameters for three limiting-case assumptions of the hypoxia / FMISO uptake relationship. {sup 18}FMISO-PET images from 2 patients (T3N0M0) from the RHYTHM trial (Investigating Hypoxia in Rectal Tumours NCT02157246) were chosen to delineate a hypoxic region (GTV-MISO defined as tumor-to-muscle ratio > 1.3) within the anatomical GTV. Three VMAT treatment plans were created in Eclipse (Varian): STANDARD (45Gy / 25 fractions to PTV4500); BOOST-GTV (simultaneous integrated boost of 60Gy / 25fr to GTV +0.5cm) and BOOST-MISO (60Gy / 25fr to GTV-MISO+0.5cm). GTV mean dose (in EQD2), iTSCP and normal tissue dose-volume metrics (small bowel, bladder, anus, and femoral heads) were recorded. Results: Patient A showed small hypoxic volume (15.8% of GTV) and Patient B moderate hypoxic volume (40.2% of GTV). Dose escalation to 60Gy was achievable, and doses to femoral heads and small bowel in BOOST plans were comparable to STANDARD plans. For patient A, a reduced maximum bladder dose was observed in BOOST-MISO compared to BOOST-GTV (D0.1cc 49.2Gy vs 54.0Gy). For patient B, a smaller high dose volume was observed for the anus region in BOOST-MISO compared to BOOST-GTV (V55Gy 19.9% vs 100%), which could potentially reduce symptoms of fecal incontinence. For BOOST-MISO, the largest iTSCPs (A: 95.5% / B: 90.0%) assumed local correlation between FMISO uptake and hypoxia, and approached iTSCP values seen for BOOST-GTV (A: 96.1% / B: 90.5%). Conclusion: Hypoxia-guided dose-boosting is predicted to improve local control in rectal tumors when FMISO is spatially correlated to hypoxia, and to reduce dose to organs-at-risk compared to boosting the whole GTV. This could lead to organ

  18. Tumor hypoxia adversely affects the prognosis of carcinoma of the head and neck and soft tissue sarcoma

    International Nuclear Information System (INIS)

    Brizel, David M.; Dewhirst, Mark W.; Sibley, Gregory S.; Scully, Sean P.; Harrelson, John M.; Scher, Richard L.; Prosnitz, Leonard R.

    1996-01-01

    Purpose The development of modern polarographic electrode technology has led to a resurgence in the clinical assessment of tumor oxygenation. Tumor hypoxia adversely affects short term clinical radiation response of head and neck cancer lymph node metastases and long term disease-free survival (DFS) in cervix carcinoma. This study was performed to evaluate the influence that tumor hypoxia exerts on the DFS of patients with soft tissue sarcoma (STS) and squamous carcinoma of the head and neck (SCCHN). Methods and Materials Pretreatment tumor pO 2 was assessed in STS and SCCHN patients using the Eppendorf polarographic electrode system. pO 2 probe placement was performed under CT scan guidance to ensure that measurements were obtained only from the tumor and in order to avoid measurement through areas of overt necrosis. A minimum of 3 measurement tracks that ranged in length from 10-35 mm was obtained from each tumor. A minimum of 100 measured points was taken from each tumor. All SCCHN patients had pO 2 measurements taken from locally advanced primaries (T3 or T4) or neck nodes ≥ 1.5 cm diameter. Treatment consisted of once or twice daily irradiation (70-75 Gy) +/- planned neck dissection (for ≥N2A disease) according to institutional treatment protocols. All STS patients had high grade tumors and received preoperative irradiation (2 Gy/day to 50 Gy) + hyperthermia followed by resection. DFS was measured by the Kaplan-Meier product limit method. The log rank technique was used to compare the DFS of different groups of patients. Single factor analysis of variance was used to compare tumor median pO 2 and tumor volume (STS) or stage (SCCHN) in those patients who relapsed versus those who did not. Correlation coefficients were calculated to examine the relationship between tumor volume and tumor oxygenation. Results Since November, 1992, 28 SCCHN and 33 STS patients have undergone tumor pO 2 measurement and have minimum followup of 6 months. The actuarial DFS at 12

  19. Irradiation-Dependent Effects on Tumor Perfusion and Endogenous and Exogenous Hypoxia Markers in an A549 Xenograft Model

    International Nuclear Information System (INIS)

    Fokas, Emmanouil; Haenze, Joerg; Kamlah, Florentine; Eul, Bastian G.; Lang, Nico; Keil, Boris; Heverhagen, Johannes T.; Engenhart-Cabillic, Rita; An Hanxiang; Rose, Frank

    2010-01-01

    Purpose: Hypoxia is a major determinant of tumor radiosensitivity, and microenvironmental changes in response to ionizing radiation (IR) are often heterogenous. We analyzed IR-dependent changes in hypoxia and perfusion in A549 human lung adenocarcinoma xenografts. Materials and Methods: Immunohistological analysis of two exogenously added chemical hypoxic markers, pimonidazole and CCI-103F, and of the endogenous marker Glut-1 was performed time dependently after IR. Tumor vessels and apoptosis were analyzed using CD31 and caspase-3 antibodies. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and fluorescent beads (Hoechst 33342) were used to monitor vascular perfusion. Results: CCI-103F signals measuring the fraction of hypoxic areas after IR were significantly decreased by approximately 50% when compared with pimonidazole signals, representing the fraction of hypoxic areas from the same tumors before IR. Interestingly, Glut-1 signals were significantly decreased at early time point (6.5 h) after IR returning to the initial levels at 30.5 h. Vascular density showed no difference between irradiated and control groups, whereas apoptosis was significantly induced at 10.5 h post-IR. DCE-MRI indicated increased perfusion 1 h post-IR. Conclusions: The discrepancy between the hypoxic fractions of CCI-103F and Glut-1 forces us to consider the possibility that both markers reflect different metabolic alterations of tumor microenvironment. The reliability of endogenous markers such as Glut-1 to measure reoxygenation in irradiated tumors needs further consideration. Monitoring tumor microvascular response to IR by DCE-MRI and measuring tumor volume alterations should be encouraged.

  20. Iodine-124-labeled iodo-azomycin-galactoside imaging of tumor hypoxia in mice with serial microPET scanning

    Energy Technology Data Exchange (ETDEWEB)

    Zanzonico, Pat; O' Donoghue, Joseph; Cai, Shangde; Larson, Steven; Wen, Bixiu; Chen, Yuchun; Finn, Ronald; Ruan, Shutian; Humm, John; Ling, Clifton [Memorial Sloan Kettering Cancer Center, 1275 York Avenue, NY 10021, New York (United States); Chapman, J.Donald; Schneider, Richard [Fox Chase Cancer Center, Philadelphia, PA (United States); Gerweck, Leo [Massachusetts General Hospital, Boston, MA (United States)

    2004-01-01

    In the current study, serial microPET imaging was used to evaluate iodine-124-labeled iodo-azomycin-galactoside ({sup 124}I-IAZG) (4.2-day physical half-life) as a hypoxia imaging agent in 17 MCa breast tumors and six FSaII fibrosarcomas implanted in mice. For comparison, another promising hypoxic-cell PET radiotracer, fluorine-18-labeled fluoro-misonidazole ({sup 18}F-FMISO), was also imaged in the same tumor-bearing animals. Twelve animals were also imaged with {sup 18}F-labeled fluoro-deoxyglucose ({sup 18}F-FDG). In addition, histological examination was performed, and direct measurement of tumor oxygenation status carried out with the Oxylite probe system. Two size groups were used, relatively well-oxygenated tumors in the range of 80-180 mg were designated as small, and those >300 mg and highly hypoxic, as large. Based on the data from 11 MCa and six FSaII tumors, both {sup 124}I-IAZG and {sup 18}F-FMISO images showed high tracer uptake in the large tumors. In {sup 18}F-FMISO images at 1, 3-4, and 6-8 h post-injection (p.i.), there was considerable whole-body background activity. In contrast, {sup 124}I-IAZG imaging was optimal when performed at 24-48 h p.i., when the whole-body background had dissipated considerably. As a result, the {sup 124}I-IAZG images at 24-48 h p.i. had higher tumor to whole-body activity contrast than the {sup 18}F-FMISO images at 3-6 h p.i. Region-of-interest analysis was performed as a function of time p.i. and indicated a tumor uptake of 5-10% (of total-body activity) for FMISO at 3-6 h p.i., and of 17% for IAZG at 48 h p.i. This was corroborated by biodistribution data in that the tumor-to-normal tissue (T/N, normal tissues of blood, heart, lung, liver, spleen, kidney, intestine, and muscle) activity ratios of IAZG at 24 h p.i. was 1.5-2 times higher than those of FMISO at 3 h p.i., with the exception of stomach. Statistical analysis indicated that these differences in T/N ratios were significant. The small tumors were visualized

  1. Role of Cyclooxygenase-2 on Intermittent Hypoxia-Induced Lung Tumor Malignancy in a Mouse Model of Sleep Apnea.

    Science.gov (United States)

    Campillo, Noelia; Torres, Marta; Vilaseca, Antoni; Nonaka, Paula Naomi; Gozal, David; Roca-Ferrer, Jordi; Picado, César; Montserrat, Josep Maria; Farré, Ramon; Navajas, Daniel; Almendros, Isaac

    2017-03-16

    An adverse role for obstructive sleep apnea (OSA) in cancer epidemiology and outcomes has recently emerged from clinical and animal studies. In animals, intermittent hypoxia (IH) mimicking OSA promotes tumor malignancy both directly and via host immune alterations. We hypothesized that IH could potentiate cancer aggressiveness through activation of the cyclooxygenase-2 (COX-2) pathway and the concomitant increases in prostaglandin E2 (PGE 2 ). The contribution of the COX-2 in IH-induced enhanced tumor malignancy was assessed using celecoxib as a COX-2 specific inhibitor in a murine model of OSA bearing Lewis lung carcinoma (LLC1) tumors. Exposures to IH accelerated tumor progression with a tumor associated macrophages (TAMs) shift towards a pro-tumoral M2 phenotype. Treatment with celecoxib prevented IH-induced adverse tumor outcomes by inhibiting IH-induced M2 polarization of TAMs. Furthermore, TAMs isolated from IH-exposed mice treated with celecoxib reduced the proliferation of LLC1 naïve cells, while the opposite occurred with placebo-treated IH-exposed mice. Finally, in vitro IH exposures of murine macrophages and LLC1 cells showed that both cell types increased PGE 2 release in response to IH. These results suggest a crucial role for the COX-2 signaling pathway in the IH-exacerbated malignant processes, and designate macrophages and lung adenocarcinoma cells, as potential sources of PGE 2 .

  2. In Vivo Imaging Reveals Significant Tumor Vascular Dysfunction and Increased Tumor Hypoxia-Inducible Factor-1α Expression Induced by High Single-Dose Irradiation in a Pancreatic Tumor Model

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, Azusa [Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario (Canada); Department of Medical Biophysics, University of Toronto, Toronto, Ontario (Canada); Chen, Yonghong; Bu, Jiachuan; Mujcic, Hilda [Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario (Canada); Wouters, Bradly G. [Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario (Canada); Department of Medical Biophysics, University of Toronto, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); DaCosta, Ralph S., E-mail: rdacosta@uhnres.utoronto.ca [Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario (Canada); Department of Medical Biophysics, University of Toronto, Toronto, Ontario (Canada); Techna Institute, University Health Network, Toronto, Ontario (Canada)

    2017-01-01

    Purpose: To investigate the effect of high-dose irradiation on pancreatic tumor vasculature and microenvironment using in vivo imaging techniques. Methods and Materials: A BxPC3 pancreatic tumor xenograft was established in a dorsal skinfold window chamber model and a subcutaneous hind leg model. Tumors were irradiated with a single dose of 4, 12, or 24 Gy. The dorsal skinfold window chamber model was used to assess tumor response, vascular function and permeability, platelet and leukocyte adhesion to the vascular endothelium, and tumor hypoxia for up to 14 days after 24-Gy irradiation. The hind leg model was used to monitor tumor size, hypoxia, and vascularity for up to 65 days after 24-Gy irradiation. Tumors were assessed histologically to validate in vivo observations. Results: In vivo fluorescence imaging revealed temporary vascular dysfunction in tumors irradiated with a single dose of 4 to 24 Gy, but most significantly with a single dose of 24 Gy. Vascular functional recovery was observed by 14 days after irradiation in a dose-dependent manner. Furthermore, irradiation with 24 Gy caused platelet and leukocyte adhesion to the vascular endothelium within hours to days after irradiation. Vascular permeability was significantly higher in irradiated tumors compared with nonirradiated controls 14 days after irradiation. This observation corresponded with increased expression of hypoxia-inducible factor-1α in irradiated tumors. In the hind leg model, irradiation with a single dose of 24 Gy led to tumor growth delay, followed by tumor regrowth. Conclusions: Irradiation of the BxPC3 tumors with a single dose of 24 Gy caused transient vascular dysfunction and increased expression of hypoxia-inducible factor-1α. Such biological changes may impact tumor response to high single-dose and hypofractionated irradiation, and further investigations are needed to better understand the clinical outcomes of stereotactic body radiation therapy.

  3. Enhanced Cellular Ablation by Attenuating Hypoxia Status and Reprogramming Tumor-Associated Macrophages via NIR Light-Responsive Upconversion Nanocrystals.

    Science.gov (United States)

    Ai, Xiangzhao; Hu, Ming; Wang, Zhimin; Lyu, Linna; Zhang, Wenmin; Li, Juan; Yang, Huanghao; Lin, Jun; Xing, Bengang

    2018-02-27

    Near-infrared (NIR) light-mediated photodynamic therapy (PDT), especially based on lanthanide-doped upconversion nanocrystals (UCNs), have been extensively investigated as a promising strategy for effective cellular ablation owing to their unique optical properties to convert NIR light excitation into multiple short-wavelength emissions. Despite the deep tissue penetration of NIR light in living systems, the therapeutic efficiency is greatly restricted by insufficient oxygen supply in hypoxic tumor microenvironment. Moreover, the coexistent tumor-associated macrophages (TAMs) play critical roles in tumor recurrence during the post-PDT period. Herein, we developed a unique photosensitizer-loaded UCNs nanoconjugate (PUN) by integrating manganese dioxide (MnO 2 ) nanosheets and hyaluronic acid (HA) biopolymer to improve NIR light-mediated PDT efficacy through attenuating hypoxia status and synergistically reprogramming TAMs populations. After the reaction with overproduced H 2 O 2 in acidic tumor microenvironment, the MnO 2 nanosheets were degraded for the production of massive oxygen to greatly enhance the oxygen-dependent PDT efficiency upon 808 nm NIR light irradiation. More importantly, the bioinspired polymer HA could effectively reprogram the polarization of pro-tumor M2-type TAMs to anti-tumor M1-type macrophages to prevent tumor relapse after PDT treatment. Such promising results provided the great opportunities to achieve enhanced cellular ablation upon NIR light-mediated PDT treatment by attenuating hypoxic tumor microenvironment, and thus facilitated the rational design of new generations of nanoplatforms toward immunotherapy to inhibit tumor recurrence during post-PDT period.

  4. Iodine-124-labeled iodo-azomycin-galactoside imaging of tumor hypoxia in mice with serial microPET scanning

    International Nuclear Information System (INIS)

    Zanzonico, Pat; O'Donoghue, Joseph; Cai, Shangde; Larson, Steven; Wen, Bixiu; Chen, Yuchun; Finn, Ronald; Ruan, Shutian; Humm, John; Ling, Clifton; Chapman, J.Donald; Schneider, Richard; Gerweck, Leo

    2004-01-01

    In the current study, serial microPET imaging was used to evaluate iodine-124-labeled iodo-azomycin-galactoside ( 124 I-IAZG) (4.2-day physical half-life) as a hypoxia imaging agent in 17 MCa breast tumors and six FSaII fibrosarcomas implanted in mice. For comparison, another promising hypoxic-cell PET radiotracer, fluorine-18-labeled fluoro-misonidazole ( 18 F-FMISO), was also imaged in the same tumor-bearing animals. Twelve animals were also imaged with 18 F-labeled fluoro-deoxyglucose ( 18 F-FDG). In addition, histological examination was performed, and direct measurement of tumor oxygenation status carried out with the Oxylite probe system. Two size groups were used, relatively well-oxygenated tumors in the range of 80-180 mg were designated as small, and those >300 mg and highly hypoxic, as large. Based on the data from 11 MCa and six FSaII tumors, both 124 I-IAZG and 18 F-FMISO images showed high tracer uptake in the large tumors. In 18 F-FMISO images at 1, 3-4, and 6-8 h post-injection (p.i.), there was considerable whole-body background activity. In contrast, 124 I-IAZG imaging was optimal when performed at 24-48 h p.i., when the whole-body background had dissipated considerably. As a result, the 124 I-IAZG images at 24-48 h p.i. had higher tumor to whole-body activity contrast than the 18 F-FMISO images at 3-6 h p.i. Region-of-interest analysis was performed as a function of time p.i. and indicated a tumor uptake of 5-10% (of total-body activity) for FMISO at 3-6 h p.i., and of 17% for IAZG at 48 h p.i. This was corroborated by biodistribution data in that the tumor-to-normal tissue (T/N, normal tissues of blood, heart, lung, liver, spleen, kidney, intestine, and muscle) activity ratios of IAZG at 24 h p.i. was 1.5-2 times higher than those of FMISO at 3 h p.i., with the exception of stomach. Statistical analysis indicated that these differences in T/N ratios were significant. The small tumors were visualized in the 18 F-FDG images, but not in the 124 I

  5. Radiation response and cure rate of human colon adenocarcinoma spheroids of different size: the significance of hypoxia on tumor control modelling.

    Science.gov (United States)

    Buffa, F M; West, C; Byrne, K; Moore, J V; Nahum, A E

    2001-03-15

    To evaluate the adequacy of a Poisson tumor control probability (tcp) model and the impact of hypoxia on tumor cure. A human colon adenocarcinoma cell line, WiDr, was grown as multicellular spheroids of different diameters. Measurements were made of cell survival and spheroid cure following 300-kV X-ray external beam irradiation in air and nitrogen. Cell survival data were fitted using a two-compartment and an oxygen diffusion model. Spheroid cure data were fitted using the tcp model. Hypoxia was seen only for spheroids greater than 500 microm in diameter. For small spheroids tcp estimates of radiosensitivity and clonogenic number showed excellent agreement with experimentally derived values. For large spheroids, although tcp estimates of radiosensitivity were comparable with measurements, estimates of the clonogenic number were considerably lower than the experimental count. Reoxygenation of large spheroids before irradiation resulted in the tcp estimates of the number of clonogenic cells agreeing with measured values. When hypoxia was absent, the tcp model accurately predicted cure from measured radiosensitivity and clonogen number. When hypoxia was present, the number of cells capable of regrowth in situ was considerably lower than the number of clonogenic cells that initially survived irradiation. As this counteracted the decreased radiosensitivity, hypoxia was less important for cure than predicted from cell survival assays. This finding suggests that chronic hypoxia may not limit directly the success of radiation therapy.

  6. Platelet-activating factor, tumor necrosis factor, hypoxia and necrotizing enterocolitis.

    Science.gov (United States)

    Hsueh, W; Caplan, M S; Sun, X; Tan, X; MacKendrick, W; Gonzalez-Crussi, F

    1994-01-01

    The pathogenesis of necrotizing enterocolitis (NEC) is poorly understood. We have established several animal models of NEC by using a combination of various stimuli and stress, including endotoxin, PAF, TNF, and hypoxia. We discuss the mechanism of their actions and the possible roles of these factors in the pathogenesis of human NEC.

  7. Hypoxia in Tumor Angiogenesis and Metastasis: Evaluation of VEGF and MMP Over-expression and Down-Regulation of HIF-1alpha with RNAi in Hypoxic Tumor Cells

    Science.gov (United States)

    Shah, Shruti

    Background: As tumor mass grows beyond a few millimeters in diameter, the angiogenic "switch" is turned on leading to recruitment of blood vessels from surrounding artery and veins. However, the tumor mass is poorly perfused and there are pockets of hypoxia or lower oxygen concentrations relative to normal tissue. Hypoxia-inducing factor-1a (HIF-1a), a transcription factor, is activated when the oxygen concentration is low. Upon activation of HIF-1a, a number of other genes also turn on that allows the tumor to become more aggressive and resistant to therapy. Purpose: The main objectives of this study were to evaluate the effect of hypoxia-induced HIF-1a followed by over-expression of angiogenic and metastatic markers in tumor cells and down-regulation of HIF-1a using nanoparticle-delivered RNA interference therapy. Methods: Human ovarian (SKOV3) and breast (MDA-MB-231) adenocarcinoma cells were incubated under normoxic and hypoxic conditions. Following hypoxia treatment of the cells, HIF-1α, vascular endothelial growth factor (VEGF), matrix metalloproteinase 2 (MMP-2), and MMP-9 expression was analyzed qualitatively and quantitatively. For intracellular delivery of HIF-1a gene silencing small interfering RNA (siRNA), type B gelatin nanoparticles were fabricated using the solvent displacement method and the surface was modified with poly(ethylene glycol) (PEG, Mol. wt. 2kDa). Cellular uptake and distribution of the nanoparticles was observed with Cy3-siRNA loaded, FITC-conjugated gelatin nanoparticles. Cytotoxicity of the nanoparticle formulations was evaluated in both the cell lines. siRNA was transfected in the gelatin nanoparticles under hypoxic conditions. Total cellular protein and RNA were extracted for analysis of HIF1a, VEGF, MMP-2 and MMP-9 expression. Results: MDA-MB-231 and SKOV3 cells show increased expression of HIF1a under hypoxic conditions compared to baseline levels at normoxic conditions. ELISA and western blots of VEGF, MMP-2 and MMP-9 appear to

  8. Endostatin improves radioresponse and blocks tumor revascularization after radiation therapy for A431 xenografts in mice

    International Nuclear Information System (INIS)

    Itasaka, Satoshi; Komaki, Ritsuko; Herbst, Roy S.; Shibuya, Keiko; Shintani, Tomoaki D.D.S.; Hunter, Nancy R. M.S.; Onn, Amir; Bucana, Corazon D.; Milas, Luka; Ang, K. Kian; O'Reilly, Michael S.

    2007-01-01

    Purpose: Clinical trials of antiangiogenic agents used alone for advanced malignancy have been disappointing but preclinical studies suggest that the addition of radiation therapy could improve antitumor efficacy. To test the hypothesis that antiangiogenic therapy combined with radiation therapy can overcome the limitations of antiangiogenic monotherapy, we studied the effects of endostatin combined with radiation on the growth and vascularization of A431 human epidermoid carcinomas growing intramuscularly in the legs of mice. Methods and Materials: Mice with established A431 human epidermoid leg tumors were treated with radiation, endostatin, both radiation and endostatin, or vehicle control. The experiment was repeated and mice from each group were killed at 2, 7, and 10 days after irradiation so that tumor tissue could be obtained to further analyze the kinetics of the antitumor, antivascular, and antiangiogenic response to therapy. Results: Endostatin enhanced the antitumor effects of radiation, and prolonged disease-free survival was observed in the combined treatment group. Endothelial cell proliferation was increased in tumors after irradiation but was blocked by the concurrent administration of endostatin, and the combination of endostatin with radiation enhanced endothelial cell apoptosis within 48 h after irradiation. Expression of vascular endothelial growth factor, interleukin-8, and matrix metalloproteinase-2 were increased in tumors after irradiation, and this increase was blocked by concurrent administration of endostatin. Conclusion: These data indicate that endostatin can block tumor revascularization after radiation therapy and thereby augment radioresponse

  9. A Combination of Radiation and the Hypoxia-Activated Prodrug Evofosfamide (TH-302 is Efficacious against a Human Orthotopic Pancreatic Tumor Model

    Directory of Open Access Journals (Sweden)

    Carla Hajj

    2017-10-01

    Full Text Available This study was designed to investigate the effect of single-dose radiation therapy (RT in combination with evofosfamide (TH-302, a hypoxia-activated prodrug, in a pre-clinical model of pancreatic cancer. AsPC1 tumors were implanted orthotopically in the pancreas of nude mice. Tumors were treated with 15 Gy of RT, using a 1 cm diameter field, and delivered as a continuous arc. Image-guidance to center the field on the tumor was based on CT imaging with intraperitoneal contrast. Evofosfamide (100 mg/kg, i.p. was administered 3 hours before RT. Tumor volumes were measured using ultrasound, and regrowth curves were plotted. Tumor hypoxia and cell proliferation were measured using pimonidazole and the thymidine analog EdU, respectively. In vitro clonogenic assays were performed. Tumors were shown to contain substantial areas of hypoxia, as calculated by percent pimonidazole staining. Evofosfamide was active in these tumors, as demonstrated by a significant reduction in uptake of the thymidine analog EdU. This effect was visible in oxygenated tissue, consistent with the previously reported bystander effects of evofosfamide. RT produced significant regrowth delay, as did evofosfamide. The combination of both agents produced a growth delay that was at least equal to the sum of the two treatments given separately. The improvement in tumor response when evofosfamide is combined with RT supports the hypothesis that hypoxia is a cause of radioresistance in high dose RT for pancreatic cancer. Assessing the efficacy and safety of stereotactic radiation treatment and evofosfamide is warranted in patients with locally advanced pancreatic cancer.

  10. Identification of tumor specimens by DNA analysis in a case of histocytological paraffin tissue block swapping

    Science.gov (United States)

    Raina, Anupuma; Yadav, Bhuvnesh; Ali, Sher; Das Dogra, Tirath

    2011-01-01

    We report on a patient who was diagnosed with high-grade breast carcinoma by all the pre-surgery clinical evidence of malignancy, but histopathological reports did not reveal any such tumor residue in the post-surgical tissue block. This raised a suspicion that either exchange of block, labeling error, or a technical error took place during gross examination of the tissue. The mastectomy residue was unprocurable to sort out the problem. So, two doubtful paraffin blocks were sent for DNA fingerprinting analysis. The partial DNA profiles (8-9/15 loci) were obtained from histocytological blocks. The random matching probability for both the paraffin blocks and the patient’s blood were found to be 1 in 4.43E4, 1.89E6, and 8.83E13, respectively for Asian population. Multiplex short tandem repeat analysis applied in this case determined that the cause of tumor absence was an error in gross examination of the post-surgical tissue. Moreover, the analysis helped in justifying the therapy given to the patient. Thus, with DNA fingerprinting technique, it was concluded that there was no exchange of the blocks between the two patients operated on the same day and the treatment given to the concerned patient was in the right direction. PMID:21674839

  11. Automatic block-matching registration to improve lung tumor localization during image-guided radiotherapy

    Science.gov (United States)

    Robertson, Scott Patrick

    To improve relatively poor outcomes for locally-advanced lung cancer patients, many current efforts are dedicated to minimizing uncertainties in radiotherapy. This enables the isotoxic delivery of escalated tumor doses, leading to better local tumor control. The current dissertation specifically addresses inter-fractional uncertainties resulting from patient setup variability. An automatic block-matching registration (BMR) algorithm is implemented and evaluated for the purpose of directly localizing advanced-stage lung tumors during image-guided radiation therapy. In this algorithm, small image sub-volumes, termed "blocks", are automatically identified on the tumor surface in an initial planning computed tomography (CT) image. Each block is independently and automatically registered to daily images acquired immediately prior to each treatment fraction. To improve the accuracy and robustness of BMR, this algorithm incorporates multi-resolution pyramid registration, regularization with a median filter, and a new multiple-candidate-registrations technique. The result of block-matching is a sparse displacement vector field that models local tissue deformations near the tumor surface. The distribution of displacement vectors is aggregated to obtain the final tumor registration, corresponding to the treatment couch shift for patient setup correction. Compared to existing rigid and deformable registration algorithms, the final BMR algorithm significantly improves the overlap between target volumes from the planning CT and registered daily images. Furthermore, BMR results in the smallest treatment margins for the given study population. However, despite these improvements, large residual target localization errors were noted, indicating that purely rigid couch shifts cannot correct for all sources of inter-fractional variability. Further reductions in treatment uncertainties may require the combination of high-quality target localization and adaptive radiotherapy.

  12. Rapid uptake of glucose and lactate, and not hypoxia, induces apoptosis in three-dimensional tumor tissue culture.

    Science.gov (United States)

    Kasinskas, Rachel W; Venkatasubramanian, Raja; Forbes, Neil S

    2014-04-01

    The spatial arrangement of cellular metabolism in tumor tissue critically affects the treatment of cancer. However, little is known about how diffusion and cellular uptake relate to intracellular metabolism and cell death in three dimensions. To quantify these mechanisms, fluorescent microscopy and multicellular tumor cylindroids were used to measure pH and oxygen profiles, and quantify the distribution of viable, apoptotic and necrotic cells. Spheroid dissociation, enzymatic analysis, and mass spectrometry were used to measure concentration profiles of glucose, lactate and glutamine. A mathematical model was used to integrate these measurements and calculate metabolic rate parameters. It was found that large cylindroids, >500 μm in diameter, contained apoptotic and necrotic cells, whereas small cylindroids contained apoptotic but not necrotic cells. The center of cylindroids was found to be acidic but not hypoxic. From the edge to the center, concentrations of glucose, lactate and glutamine decreased rapidly. Throughout the cell masses lactate was consumed and not produced. These measurements indicate that apoptosis was the primary mechanism of cell death; acidity was not caused by lactic acid; and cell death was caused by depletion of carbon sources and not hypoxia. The mathematical model showed that the transporter enzymes for glucose and lactate were not saturated; oxygen uptake was limited by intracellular metabolism; and oxygen uptake was not limited by membrane-transport or diffusion. Unsaturated transmembrane uptake may be the cause of both proliferative and apoptotic regimes in cancer. These results suggest that transporter enzymes are excellent targets for treating well oxygenated tumors.

  13. A block matching-based registration algorithm for localization of locally advanced lung tumors.

    Science.gov (United States)

    Robertson, Scott P; Weiss, Elisabeth; Hugo, Geoffrey D

    2014-04-01

    To implement and evaluate a block matching-based registration (BMR) algorithm for locally advanced lung tumor localization during image-guided radiotherapy. Small (1 cm(3)), nonoverlapping image subvolumes ("blocks") were automatically identified on the planning image to cover the tumor surface using a measure of the local intensity gradient. Blocks were independently and automatically registered to the on-treatment image using a rigid transform. To improve speed and robustness, registrations were performed iteratively from coarse to fine image resolution. At each resolution, all block displacements having a near-maximum similarity score were stored. From this list, a single displacement vector for each block was iteratively selected which maximized the consistency of displacement vectors across immediately neighboring blocks. These selected displacements were regularized using a median filter before proceeding to registrations at finer image resolutions. After evaluating all image resolutions, the global rigid transform of the on-treatment image was computed using a Procrustes analysis, providing the couch shift for patient setup correction. This algorithm was evaluated for 18 locally advanced lung cancer patients, each with 4-7 weekly on-treatment computed tomography scans having physician-delineated gross tumor volumes. Volume overlap (VO) and border displacement errors (BDE) were calculated relative to the nominal physician-identified targets to establish residual error after registration. Implementation of multiresolution registration improved block matching accuracy by 39% compared to registration using only the full resolution images. By also considering multiple potential displacements per block, initial errors were reduced by 65%. Using the final implementation of the BMR algorithm, VO was significantly improved from 77% ± 21% (range: 0%-100%) in the initial bony alignment to 91% ± 8% (range: 56%-100%;p < 0.001). Left-right, anterior-posterior, and

  14. Blocking Blood Flow to Solid Tumors by Destabilizing Tubulin: An Approach to Targeting Tumor Growth.

    Science.gov (United States)

    Pérez-Pérez, María-Jesús; Priego, Eva-María; Bueno, Oskía; Martins, Maria Solange; Canela, María-Dolores; Liekens, Sandra

    2016-10-13

    The unique characteristics of the tumor vasculature offer the possibility to selectively target tumor growth and vascularization using tubulin-destabilizing agents. Evidence accumulated with combretastatin A-4 (CA-4) and its prodrug CA-4P support the therapeutic value of compounds sharing this mechanism of action. However, the chemical instability and poor solubility of CA-4 demand alternative compounds that are able to surmount these limitations. This Perspective illustrates the different classes of compounds that behave similar to CA-4, analyzes their binding mode to αβ-tubulin according to recently available structural complexes, and includes described approaches to improve their delivery. In addition, dissecting the mechanism of action of CA-4 and analogues allows a closer insight into the advantages and drawbacks associated with these tubulin-destabilizing agents that behave as vascular disrupting agents (VDAs).

  15. A block matching-based registration algorithm for localization of locally advanced lung tumors

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, Scott P.; Weiss, Elisabeth; Hugo, Geoffrey D., E-mail: gdhugo@vcu.edu [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia, 23298 (United States)

    2014-04-15

    Purpose: To implement and evaluate a block matching-based registration (BMR) algorithm for locally advanced lung tumor localization during image-guided radiotherapy. Methods: Small (1 cm{sup 3}), nonoverlapping image subvolumes (“blocks”) were automatically identified on the planning image to cover the tumor surface using a measure of the local intensity gradient. Blocks were independently and automatically registered to the on-treatment image using a rigid transform. To improve speed and robustness, registrations were performed iteratively from coarse to fine image resolution. At each resolution, all block displacements having a near-maximum similarity score were stored. From this list, a single displacement vector for each block was iteratively selected which maximized the consistency of displacement vectors across immediately neighboring blocks. These selected displacements were regularized using a median filter before proceeding to registrations at finer image resolutions. After evaluating all image resolutions, the global rigid transform of the on-treatment image was computed using a Procrustes analysis, providing the couch shift for patient setup correction. This algorithm was evaluated for 18 locally advanced lung cancer patients, each with 4–7 weekly on-treatment computed tomography scans having physician-delineated gross tumor volumes. Volume overlap (VO) and border displacement errors (BDE) were calculated relative to the nominal physician-identified targets to establish residual error after registration. Results: Implementation of multiresolution registration improved block matching accuracy by 39% compared to registration using only the full resolution images. By also considering multiple potential displacements per block, initial errors were reduced by 65%. Using the final implementation of the BMR algorithm, VO was significantly improved from 77% ± 21% (range: 0%–100%) in the initial bony alignment to 91% ± 8% (range: 56%–100%;p < 0

  16. A block matching-based registration algorithm for localization of locally advanced lung tumors

    International Nuclear Information System (INIS)

    Robertson, Scott P.; Weiss, Elisabeth; Hugo, Geoffrey D.

    2014-01-01

    Purpose: To implement and evaluate a block matching-based registration (BMR) algorithm for locally advanced lung tumor localization during image-guided radiotherapy. Methods: Small (1 cm 3 ), nonoverlapping image subvolumes (“blocks”) were automatically identified on the planning image to cover the tumor surface using a measure of the local intensity gradient. Blocks were independently and automatically registered to the on-treatment image using a rigid transform. To improve speed and robustness, registrations were performed iteratively from coarse to fine image resolution. At each resolution, all block displacements having a near-maximum similarity score were stored. From this list, a single displacement vector for each block was iteratively selected which maximized the consistency of displacement vectors across immediately neighboring blocks. These selected displacements were regularized using a median filter before proceeding to registrations at finer image resolutions. After evaluating all image resolutions, the global rigid transform of the on-treatment image was computed using a Procrustes analysis, providing the couch shift for patient setup correction. This algorithm was evaluated for 18 locally advanced lung cancer patients, each with 4–7 weekly on-treatment computed tomography scans having physician-delineated gross tumor volumes. Volume overlap (VO) and border displacement errors (BDE) were calculated relative to the nominal physician-identified targets to establish residual error after registration. Results: Implementation of multiresolution registration improved block matching accuracy by 39% compared to registration using only the full resolution images. By also considering multiple potential displacements per block, initial errors were reduced by 65%. Using the final implementation of the BMR algorithm, VO was significantly improved from 77% ± 21% (range: 0%–100%) in the initial bony alignment to 91% ± 8% (range: 56%–100%;p < 0.001). Left

  17. Quercetin enhances hypoxia-mediated apoptosis via direct inhibition of AMPK activity in HCT116 colon cancer.

    Science.gov (United States)

    Kim, Hak-Su; Wannatung, Tirawat; Lee, Sooho; Yang, Woo Kyeom; Chung, Sung Hyun; Lim, Jong-Seok; Choe, Wonchae; Kang, Insug; Kim, Sung-Soo; Ha, Joohun

    2012-09-01

    Tumor hypoxia is considered the best validated target in clinical oncology because of its significant contribution to chemotherapy failure and drug resistance. As an approach to target hypoxia, we assessed the potential of quercetin, a flavonoid widely distributed in plants, as a anticancer agent under hypoxic conditions and examined its pharmacological mechanisms by primarily focusing on the role of AMP-activated protein kinase (AMPK). Quercetin significantly attenuated tumor growth in an HCT116 cancer xenograft in vivo model with a substantial reduction of AMPK activity. In a cell culture system, quercetin more dramatically induced apoptosis of HCT116 cancer cells under hypoxic conditions than normoxic conditions, and this was tightly associated with inhibition of hypoxia-induced AMPK activity. An in vitro kinase assay demonstrated that quercetin directly inhibits AMPK activity. Inhibition of AMPK by expressing a dominant-negative form resulted in an increase of apoptosis under hypoxia, and a constitutively active form of AMPK effectively blocked quercetin-induced apoptosis under hypoxia. Collectively, our data suggest that quercetin directly inhibits hypoxia-induced AMPK, which plays a protective role against hypoxia. Quercetin also reduced the activity of hypoxia-inducible factor-1 (HIF-1), a major transcription factor for adaptive cellular response to hypoxia. Moreover, quercetin sensitized HCT116 cancer cells to the anticancer drugs cisplatin and etoposide under hypoxic conditions. Our findings suggest that AMPK may serve as a novel target for overcoming tumor hypoxia-associated negative aspects.

  18. Hypoxic inactivation of glycogen synthase kinase-3β promotes gastric tumor growth and angiogenesis by facilitating hypoxia-inducible factor-1 signaling.

    Science.gov (United States)

    Ko, Young San; Cho, Sung Jin; Park, Jinju; Choi, Yiseul; Lee, Jae-Seon; Youn, Hong-Duk; Kim, Woo Ho; Kim, Min A; Park, Jong-Wan; Lee, Byung Lan

    2016-09-01

    Since the molecular mechanism of hypoxic adaptation in cancer cells is cell-type specific, we investigated whether glycogen synthase kinase-3β (GSK-3β) activation is involved in hypoxia-induced gastric tumor promotion. Stable gastric cancer cell lines (SNU-638, SNU-484, MKN1, and MKN45) were cultured under hypoxic conditions. Cells overexpressing wild-type GSK-3β (WT-GSK-3β) or kinase-dead mutant of GSK-3β (KD-GSK-3β) were generated and used for cell culture and animal studies. In cell culture experiments, hypoxia decreased GSK-3β activation in gastric cancer cells. Cell viability and the expressions of HIF-1α protein and VEGF mRNA in gastric cancer cells were higher in KD-GSK-3β transfectants than in WT-GSK-3β transfectants under hypoxic conditions, but not under normoxic conditions. Gastric cancer xenografts showed that tumor growth, microvessel area, HIF-1α activation, and VEGF expression were higher in KD-GSK-3β tumors than in WT-GSK-3β tumors in vivo. In addition, the expression of hypoxia-induced HIF-1α protein was regulated by GSK-3β at the translational level. Our data suggest that GSK-3β is involved in hypoxic adaptation of gastric cancer cells as an inhibitory upstream regulator of the HIF-1α/VEGF signaling pathway. © 2016 APMIS. Published by John Wiley & Sons Ltd.

  19. Development of a novel fluorescent imaging probe for tumor hypoxia by use of a fusion protein with oxygen-dependent degradation domain of HIF-1α

    Science.gov (United States)

    Tanaka, Shotaro; Kizaka-Kondoh, Shinae; Harada, Hiroshi; Hiraoka, Masahiro

    2007-02-01

    More malignant tumors contain more hypoxic regions. In hypoxic tumor cells, expression of a series of hypoxiaresponsive genes related to malignant phenotype such as angiogenesis and metastasis are induced. Hypoxia-inducible factor-1 (HIF-1) is a master transcriptional activator of such genes, and thus imaging of hypoxic tumor cells where HIF-1 is active, is important in cancer therapy. We have been developing PTD-ODD fusion proteins, which contain protein transduction domain (PTD) and the VHL-mediated protein destruction motif in oxygen-dependent degradation (ODD) domain of HIF-1 alpha subunit (HIF-1α). Thus PTD-ODD fusion proteins can be delivered to any tissue in vivo through PTD function and specifically stabilized in hypoxic cells through ODD function. To investigate if PTD-ODD fusion protein can be applied to construct hypoxia-specific imaging probes, we first constructed a fluorescent probe because optical imaging enable us to evaluate a probe easily, quickly and economically in a small animal. We first construct a model fusion porein PTD-ODD-EGFP-Cy5.5 named POEC, which is PTD-ODD protein fused with EGFP for in vitro imaging and stabilization of fusion protein, and conjugated with a near-infrared dye Cy5.5. This probe is designed to be degraded in normoxic cells through the function of ODD domain and followed by quick clearance of free fluorescent dye. On the other hand, this prove is stabilized in hypoxic tumor cells and thus the dye is stayed in the cells. Between normoxic and hypoxic conditions, the difference in the clearance rate of the dye will reveals suited contrast for tumor-hypoxia imaging. The optical imaging probe has not been optimized yet but the results presented here exhibit a potential of PTD-ODD fusion protein as a hypoxia-specific imaging probe.

  20. MicroRNA-17, 20a regulates the proangiogenic function of tumor-associated macrophages via targeting hypoxia-inducible factor 2α.

    Directory of Open Access Journals (Sweden)

    Zhenqun Xu

    Full Text Available Tumor-associated macrophages (TAMs constitute a major component of the leukocyte infiltrate of most solid tumors, and they usually exhibit a proangiogenic phenotype which facilitates tumor growth in most circumstances. However, the precise mechanisms regulating the proangiogenic properties of TAMs remain largely unclear. In the present study, we found that the expression of hypoxia-inducible factor 2α (HIF-2α was significantly up-regulated in macrophages from tumor tissues of several solid tumors. Macrophages exposed to tumor cell line derived-culture supernatants (TSN also expressed high levels of HIF-2α in vitro, without a requirement for hypoxia. We identified miR-17 and miR-20a as the key regulators of HIF-2α expression in TAMs, and autocrine IL-6 played an important role in mediating the expression of miR-17, miR-20a, and thereafter HIF-2α in TAMs. Furthermore, the elevated HIF-2α in TAMs stimulated transcription of a set of proangiogenic genes such as VEGFA and PDGFB, which might in turn contribute to the angiogenic process within tumors. Our data provide evidence in support of the critical role of HIF-2α in the proangiogenic activity of TAMs and also reveal a novel mechanism by which miRNAs regulate TAM functions through modulation of HIF-2α expression under non-hypoxic conditions.

  1. Systematic analysis of 18F-FDG PET and metabolism, proliferation and hypoxia markers for classification of head and neck tumors

    International Nuclear Information System (INIS)

    Hoeben, Bianca AW; Starmans, Maud HW; Leijenaar, Ralph TH; Dubois, Ludwig J; Kogel, Albert J van der; Kaanders, Johannes HAM; Boutros, Paul C; Lambin, Philippe; Bussink, Johan

    2014-01-01

    Quantification of molecular cell processes is important for prognostication and treatment individualization of head and neck cancer (HNC). However, individual tumor comparison can show discord in upregulation similarities when analyzing multiple biological mechanisms. Elaborate tumor characterization, integrating multiple pathways reflecting intrinsic and microenvironmental properties, may be beneficial to group most uniform tumors for treatment modification schemes. The goal of this study was to systematically analyze if immunohistochemical (IHC) assessment of molecular markers, involved in treatment resistance, and 18 F-FDG PET parameters could accurately distinguish separate HNC tumors. Several imaging parameters and texture features for 18 F-FDG small-animal PET and immunohistochemical markers related to metabolism, hypoxia, proliferation and tumor blood perfusion were assessed within groups of BALB/c nu/nu mice xenografted with 14 human HNC models. Classification methods were used to predict tumor line based on sets of parameters. We found that 18 F-FDG PET could not differentiate between the tumor lines. On the contrary, combined IHC parameters could accurately allocate individual tumors to the correct model. From 9 analyzed IHC parameters, a cluster of 6 random parameters already classified 70.3% correctly. Combining all PET/IHC characteristics resulted in the highest tumor line classification accuracy (81.0%; cross validation 82.0%), which was just 2.2% higher (p = 5.2×10 -32 ) than the performance of the IHC parameter/feature based model. With a select set of IHC markers representing cellular processes of metabolism, proliferation, hypoxia and perfusion, one can reliably distinguish between HNC tumor lines. Addition of 18 F-FDG PET improves classification accuracy of IHC to a significant yet minor degree. These results may form a basis for development of tumor characterization models for treatment allocation purposes

  2. Hypoxia Inducible Factor-independent functions for the von Hippel-Lindau tumor suppressor gene

    NARCIS (Netherlands)

    Lolkema, Martijn Paul Jung Kyu

    2006-01-01

    Inactivating mutations of the von Hippel-Lindau gene (VHL) on chromosome 3p have been associated with the autosomal dominant VHL disease, characterized by extensively vascularized tumors and cysts in different organs, as well as the majority of conventional kidney cancers. The VHL gene product

  3. Post-transcriptional regulation of the tumor suppressor p53 by a novel miR-27a, with implications during hypoxia and tumorigenesis.

    Science.gov (United States)

    Maqbool, Raihana; Lone, Saife Niaz; Ul Hussain, Mahboob

    2016-10-15

    The tumor suppressor protein p53 is intricately regulated by various signaling molecules, including non-coding small RNAs, called microRNAs (miRNAs). The in silico analysis and the inverse expression status in various cell lines raised the possibility of miR-27a being a new regulator of p53. Using luciferase reporter assay and various mutational and functional analysis, we identified two putative binding sites of miR-27a on the 3'-UTR of p53. The overexpression of miR-27a in the human colorectal cancer cell line HCT-116 +/+ resulted in the decreased expression of the endogenous p53 protein levels. During hypoxia of the HCT-116 +/+ cells, p53 showed increased accumulation after 3 h, and the levels were significantly up-regulated until 24 h of hypoxia. The p53 expression dynamics during hypoxia of the HCT-116 +/+ cells were found to be inversely regulated by miR-27a expression. Moreover, using a cell viability assay, we established that after 3 h of hypoxia, the accumulation of p53 results in a decreased number of the viable HCT-116 +/+ cells and the overexpression of miR-27a resulted in an increased number of viable HCT-116 +/+ cells with a concomitant decrease in p53 expression. Additionally, our data indicated that miR-27a and p53 depict inverse expression dynamics in 50% of the human colorectal cancer samples studied, when compared with that in the adjacent normal samples. Our data established that miR-27a and the tumor suppressor protein p53 are part of the same signaling network that has important implications during hypoxia and tumorigenesis. © 2016 The Author(s); published by Portland Press Limited on behalf of the Biochemical Society.

  4. CD47-CAR-T Cells Effectively Kill Target Cancer Cells and Block Pancreatic Tumor Growth.

    Science.gov (United States)

    Golubovskaya, Vita; Berahovich, Robert; Zhou, Hua; Xu, Shirley; Harto, Hizkia; Li, Le; Chao, Cheng-Chi; Mao, Mike Ming; Wu, Lijun

    2017-10-21

    CD47 is a glycoprotein of the immunoglobulin superfamily that is often overexpressed in different types of hematological and solid cancer tumors and plays important role in blocking phagocytosis, increased tumor survival, metastasis and angiogenesis. In the present report, we designed CAR (chimeric antigen receptor)-T cells that bind CD47 antigen. We used ScFv (single chain variable fragment) from mouse CD47 antibody to generate CD47-CAR-T cells for targeting different cancer cell lines. CD47-CAR-T cells effectively killed ovarian, pancreatic and other cancer cells and produced high level of cytokines that correlated with expression of CD47 antigen. In addition, CD47-CAR-T cells significantly blocked BxPC3 pancreatic xenograft tumor growth after intratumoral injection into NSG mice. Moreover, we humanized mouse CD47 ScFv and showed that it effectively bound CD47 antigen. The humanized CD47-CAR-T cells also specifically killed ovarian, pancreatic, and cervical cancer cell lines and produced IL-2 that correlated with expression of CD47. Thus, CD47-CAR-T cells can be used as a novel cellular therapeutic agent for treating different types of cancer.

  5. Automated synthesis with HPLC purification of 18F-FMISO as specific molecular imaging probe of tumor hypoxia

    International Nuclear Information System (INIS)

    Wang Mingwei; Zhang Yingjian; Zhang Yongping

    2012-01-01

    An improved automated synthesis of 1-H-1-(3-[ 18 F] fluoro-2-hydroxypropyl)-2-nitro-imidazole ( 18 F-FMISO), a specific molecular imaging probe of tumor hypoxia, was developed using an upgraded Explora GN module integrated with Explora LC for HPLC purification in this study. The radiochemical synthesis of 18 F-FMISO was started with precursor 1-( 2'-nitro-1'-imidazolyl)-2-O-tetrahydropyranyl-3-O-tosyl-propanediol (NITTP) and included nucleophilic [ 18 F] radio-fluorination at 120℃ for 5 min and hydrolysis at 130℃ for 8 min. The automated synthesis of 18 F-FMISO, presenting fast, reliable and multi-run features, could be completed with the total synthesis time of less than 65 min and radiochemical yield of 25%∼35% (without decay correction). The quality control of 18 F-FMISO was identical with the radiopharmaceutical requirements, especially the radiochemical purity of greater than 99% and high chemical purity and specific activity own to HPLC purification. (authors)

  6. Clinical significance of assessing Her2/neu expression in gastric cancer with dual tumor tissue paraffin blocks.

    Science.gov (United States)

    Ge, Xiaowen; Wang, Haixing; Zeng, Haiying; Jin, Xuejuan; Sujie, Akesu; Xu, Chen; Liu, Yalan; Huang, Jie; Ji, Yuan; Tan, Yunshan; Liu, Tianshu; Hou, Yingyong; Qin, Jing; Sun, Yihong; Qin, Xinyu

    2015-06-01

    One paraffin block is routinely used for human epidermal growth factor receptor 2 (Her2/neu) immunohistochemistry (IHC) assessment. Here, we investigated if picking 2 paraffin blocks for Her2/neu evaluation on 1 slide is an economical, efficient, and practical method, which may reduce false negativity of Her2/neu IHC assessment due to intratumoral heterogeneity. A total of 251 gastric cancer (GC) patients were divided into a cohort using 1 tumor tissue paraffin block (single-block group, n = 132) and a cohort using dual tumor tissue paraffin blocks (dual-block group, n = 119) when evaluating Her2/neu expression status by IHC. In dual-block group, we combined the results from 2 different paraffin blocks and used the higher one as the final score. The number of IHC 1+, 2+, and 3+ specimens in the single-block group was 31 (23.5%), 40 (30.3%), and 19 (14.4%), respectively. The combined final IHC score in the dual-block group of 1+, 2+, and 3+ was 26 (21.8%), 34 (28.6%), and 23 (19.3%), respectively. Inconsistent Her2/neu expression between blocks was found in 36 (30.3%) cases in the dual-block group. The pooled data in the single-block group and the dual-block group indicated that, when using dual blocks, the Her2/neu-positive (3+) rate of GC was higher compared to that in the single-block group. Our results implied that using dual paraffin blocks to assess Her2/neu expression of GC may help identify more patients with Her2/neu-positive GC who could benefit from targeted therapy, by reducing false-negative rate of Her2 status assessment. This is an efficient, economical, and practical method for Her2/neu evaluation of GC. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Phosphorescence monitoring of hypoxic microenvironment in solid-tumors to evaluate chemotherapeutic effects using the hypoxia-sensitive iridium (III coordination compound.

    Directory of Open Access Journals (Sweden)

    Yun Zeng

    Full Text Available To utilize phosphorescence to monitor hypoxic microenvironment in solid-tumors and investigate cancer chemotherapeutic effects in vivo.A hypoxia-sensitive probe named BTP was used to monitor hypoxic microenvironment in solid-tumors. The low-dose metronomic treatment with cisplatin was used in anti-angiogenetic chemotherapeutic programs. The phosphorescence properties of BTP were detected by a spectrofluorometer. BTP cytotoxicity utilized cell necrosis and apoptosis, which were evaluated by trypan blue dye exclusion and Hoechst33342 plus propidium iodide assays. Tumor-bearing mouse models of colon adenocarcinoma were used for tumor imaging in vivo. Monitoring of the hypoxic microenvironment in tumors was performed with a Maestro 2 fluorescence imaging system. Tumor tissues in each group were harvested regularly and treated with pathological hematoxylin and eosin and immunohistochemical staining to confirm imaging results.BTP did not feature obvious cytotoxicity for cells, and tumor growth in low-dose metronomic cisplatin treated mice was significantly inhibited by chemotherapy. Hypoxic levels significantly increased due to cisplatin, as proven by the expression level of related proteins. Phosphorescence intensity in the tumors of mice in the cisplatin group was stronger and showed higher contrast than that in tumors of saline treated mice.We develop a useful phosphorescence method to evaluate the chemotherapeutic effects of cisplatin. The proposed method shows potential as a phosphorescence imaging approach for evaluating chemotherapeutic effects in vivo, especially anti-angiogenesis.

  8. An MRI Method To Map Tumor Hypoxia Using Red Blood Cells Loaded with a pO2-Responsive Gd-Agent.

    Science.gov (United States)

    Di Gregorio, Enza; Ferrauto, Giuseppe; Gianolio, Eliana; Lanzardo, Stefania; Carrera, Carla; Fedeli, Franco; Aime, Silvio

    2015-08-25

    Hypoxia is a typical hallmark of many solid tumors and often leads to therapy resistance and the development of a more aggressive cancer phenotype. Oxygen content in tissues has been evaluated using numerous different methods for several imaging modalities, but none has yet reached the required standard of spatial and temporal resolution. Magnetic Resonance Imaging (MRI) appears to be the technique of choice and several pO2-responsive probes have been designed for it over the years. In vivo translation is often hampered in Gd-relaxation agents as it is not possible to separate effects that arise from changes in local concentration from those associated with responsive properties. A novel procedure for the MRI based assessment of hypoxia is reported herein. The method relies on the combined use of Gd-DOTP- and Gd-HPDO3A-labeled red blood cells (RBCs) where the first probe acts as a vascular oxygenation-responsive agent, while the second reports the local labeled RBC concentration in a transplanted breast tumor mouse model. The MRI assessment of oxygenation state has been validated by photoacoustic imaging and ex vivo immunofluorescence. The method refines tumor staging in preclinical models and makes possible an accurate monitoring of the relationship between oxygenation and tumor growth.

  9. [Application of temporary balloon blocking technique in bone tumors surgery under the aid of CT angiography].

    Science.gov (United States)

    Fang, Cheng; Hu, Yongcheng; Huang, Hongchao; Xia, Qun; Chen, Xiaopeng; Yuan, Binbin; He, Xin; Wang, Peng

    2014-10-01

    To study the value of CT angiography (CTA) in the surgical treatment of bone tumors with the temporary balloon blocking technique. A retrospective analysis was made on the clinical data of 36 bone tumor patients between April 2008 and October 2013. There were 22 males and 14 females, aged from 25 to 83 years (mean, 46 years). The tumor located at the sacrococcygeal region in 17 cases, at the ilium in 12 cases, at the pubis in 5 cases, and at the proximal femur in 2 cases. Before surgery, CTA was performed to measure the external diameter of aortaventralis and arteria iliac communis, and the distance between the low renal artery and the abdominal aortic bifurcation as well as mark the anatomical relationship between the low renal artery, the abdominal aortic bifurcation and bony landmarks of vertebral body. According to these data, suitable balloon was chosen and the balloon positioning was guided in the surgery to completely excise tumor assisted by balloon blocking technique. The CTA results showed that the external diameter of aortaventralis and arteria iliaca communis was (1.545 ± 0.248) cm and (1.060 ± 0.205) cm respectively, and the distance between the low renal artery and the abdominal aortic bifurcation was (10.818 ± 1.165) cm. The three-dimensional reconstruction showed that the opening of the low renal artery was mainly located at L1 (16/36, 44.4%) and the abdominal aortic bifurcation mainly located at L4 (22/36, 61.1%). Effective block of abdomial aorta was performed; the blood pressure obviously increased in 3 cases after balloon inflation, and pulse of the left dorsal artery of the foot decreased in 1 case after removal of balloon, which were relieved after expectant treatment. The operation time was 118-311 minutes; the intraoperative blood loss was 200-1800 mL, 21 patients were given blood transfusion, and the amount of blood transfusion was 400-1200 mL; and the aortic clamping time was 40-136 minutes. All patients were followed up 5-44 months

  10. Radiosensitization of normoxic and hypoxic h1339 lung tumor cells by heat shock protein 90 inhibition is independent of hypoxia inducible factor-1α.

    Science.gov (United States)

    Schilling, Daniela; Bayer, Christine; Li, Wei; Molls, Michael; Vaupel, Peter; Multhoff, Gabriele

    2012-01-01

    Ionizing irradiation is a commonly accepted treatment modality for lung cancer patients. However, the clinical outcome is hampered by normal tissue toxicity and tumor hypoxia. Since tumors often have higher levels of active heat shock protein 90 (Hsp90) than normal tissues, targeting of Hsp90 might provide a promising strategy to sensitize tumors towards irradiation. Hsp90 client proteins include oncogenic signaling proteins, cell cycle activators, growth factor receptors and hypoxia inducible factor-1α (HIF-1α). Overexpression of HIF-1α is assumed to promote malignant transformation and tumor progression and thus might reduce the accessibility to radiotherapy. Herein, we describe the effects of the novel Hsp90 inhibitor NVP-AUY922 and 17-allylamino-17-demethoxygeldanamycin (17-AAG), as a control, on HIF-1α levels and radiosensitivity of lung carcinoma cells under normoxic and hypoxic conditions. NVP-AUY922 exhibited a similar biological activity to that of 17-AAG, but at only 1/10 of the dose. As expected, both inhibitors reduced basal and hypoxia-induced HIF-1α levels in EPLC-272H lung carcinoma cells. However, despite a down-regulation of HIF-1α upon Hsp90 inhibition, sensitivity towards irradiation remained unaltered in EPLC-272H cells under normoxic and hypoxic conditions. In contrast, treatment of H1339 lung carcinoma cells with NVP-AUY922 and 17-AAG resulted in a significant up-regulation of their initially high HIF-1α levels and a concomitant increase in radiosensitivity. In summary, our data show a HIF-1α-independent radiosensitization of normoxic and hypoxic H1339 lung cancer cells by Hsp90 inhibition.

  11. Ultrasound-Mediated Tumor Imaging and Nanotherapy using Drug Loaded, Block Copolymer Stabilized Perfluorocarbon Nanoemulsions

    Science.gov (United States)

    Rapoport, Natalya; Nam, Kweon-Ho; Gupta, Roohi; Gao, Zhongao; Mohan, Praveena; Payne, Allison; Todd, Nick; Liu, Xin; Kim, Taeho; Shea, Jill; Scaife, Courtney; Parker, Dennis L.; Jeong, Eun-Kee; Kennedy, Anne M.

    2011-01-01

    Perfluorocarbon nanoemulsions can deliver lipophilic therapeutic agents to solid tumors and simultaneously provide for monitoring nanocarrier biodistribution via ultrasonography and/or 19F MRI. In the first generation of block copolymer stabilized perfluorocarbon nanoemulsions, perfluoropentane (PFP) was used as the droplet forming compound. Although manifesting excellent therapeutic and ultrasound imaging properties, PFP nanoemulsions were unstable at storage, difficult to handle, and underwent hard to control phenomenon of irreversible droplet-to-bubble transition upon injection. To solve the above problems, perfluoro-15-crown-5-ether (PFCE) was used as a core forming compound in the second generation of block copolymer stabilized perfluorocarbon nanoemulsions. PFCE nanodroplets manifest both ultrasound and fluorine (19F) MR contrast properties, which allows using multimodal imaging and 19F MR spectroscopy for monitoring nanodroplet pharmacokinetics and biodistribution. In the present paper, acoustic, imaging, and therapeutic properties of unloaded and paclitaxel (PTX) loaded PFCE nanoemulsions are reported. As manifested by the 19F MR spectroscopy, PFCE nanodroplets are long circulating, with about 50% of the injected dose remaining in circulation two hours after the systemic injection. Sonication with 1-MHz therapeutic ultrasound triggered reversible droplet-to-bubble transition in PFCE nanoemulsions. Microbubbles formed by acoustic vaporization of nanodroplets underwent stable cavitation. The nanodroplet size (200 nm to 350 nm depending on a type of the shell and conditions of emulsification) as well as long residence in circulation favored their passive accumulation in tumor tissue that was confirmed by ultrasonography. In the breast and pancreatic cancer animal models, ultrasound-mediated therapy with paclitaxel-loaded PFCE nanoemulsions showed excellent therapeutic properties characterized by tumor regression and suppression of metastasis. Anticipated

  12. Hypoxia and metastasis in an orthotopic cervix cancer xenograft model

    International Nuclear Information System (INIS)

    Chaudary, Naz; Mujcic, Hilda; Wouters, Bradly G.; Hill, Richard P.

    2013-01-01

    Background: Hypoxia can promote tumor metastasis by mechanisms that are believed to result from changes in gene expression. The current study examined the role of putative metastatic genes regulated by cyclic hypoxia in relation to metastasis formation in orthotopic models of cervix cancer. Methods: Orthotopic tumors derived from ME180 human cervix cancer cells or from early generation human cervix cancer xenografts were exposed to cyclic hypoxic conditions during growth in vivo and tumor growth and lymphnode metastases were monitored. Expression of the chemokine receptor CXCR4 and various genes in the Hedgehog (Hh) pathway were inhibited using genetic (inducible shRNA vs CXCR4) small molecule (AMD3100) or antibody (5E1) treatment (CXCR4 and Hh genes, respectively) during tumor growth. Results: As reported previously, exposure of tumor bearing mice to cyclic hypoxia caused a reduction of tumor growth but a large increase in metastasis. Inhibition of CXCR4 or Hh gene activity during tumor growth further reduced primary tumor size and reduced lymphatic metastasis to levels below those seen in control mice exposed to normoxic conditions. Conclusion: Blocking CXCR4 or Hh gene expression are potential therapeutic pathways for improving cervix cancer treatment

  13. Comparative pharmacokinetics, biodistribution, metabolism and hypoxia-dependent uptake of [18F]-EF3 and [18F]-MISO in rodent tumor models

    International Nuclear Information System (INIS)

    Mahy, Pierre; Bast, Marc de; Groot, Tjibbe de; Cheguillaume, Arnaud; Gillart, Jacques; Haustermans, Karin; Labar, Daniel; Gregoire, Vincent

    2008-01-01

    Background and purpose: [ 18 F]-EF3 allows non-invasive detection of hypoxia. In the framework of its validation, we aimed at comparing its pharmacokinetics, biodistribution, metabolism and specificity for hypoxia with the hypoxia tracer [ 18 F]-FMISO. Materials and methods: C3H mice were injected IV with 3.7-18.5 MBq of one of the two tracers. For pharmacokinetics experiments, blood, urines and feces were collected. For biodistribution experiments, 13 different organs were harvested. To assess the hypoxia-specificity of the tracers, intramuscular syngeneic FSA II tumor bearing mice breathing air or carbogen were used. Animals were sacrificed from 5 to 440 min after injection. Radioactivity was assessed ex-vivo in a gamma counter. Tracer metabolites were assessed with radio-HPLC of acetonitrile soluble fractions of tissues. Results: Elimination half-life in blood (mono-exponential fit) reached 81.8 and 99.7 min for [ 18 F]-EF3 and [ 18 F]-MISO, respectively (NS). After 440 min, 71 ± 7% (mean ± SD) of injected activity of [ 18 F]-EF3 was collected in the urine while 9 ± 2% was collected in the feces, compared to 71 ± 15% and 23 ± 15% for [ 18 F]-MISO (NS). Biodistribution was similar with a homogeneous distribution in most organs as early as 5 min after injection. With time, an increased activity in organs involved in excretion (kidney, bladder, liver and GI tract) was measured for both tracers; however, an increased background activity in 'oxic' normal tissues (brain, lung, and esophagus) was also observed for [ 18 F]-MISO. The percentage of metabolites was higher for [ 18 F]-MISO compared to [ 18 F]-EF3 in nearly all samples. Tumor-to-muscle ratios (TMRs) ranging from 2 to 4 were obtained under air-breathing condition for both tracers. Conclusion: Both tracers exhibited a similar pharmacokinetics and biodistribution in mice and accumulated in an hypoxia-dependent manner in tumors. However, more aspecific activity was observed with [ 18 F]-MISO at late time

  14. HIF-1α inhibition blocks the cross talk between multiple myeloma plasma cells and tumor microenvironment

    Energy Technology Data Exchange (ETDEWEB)

    Borsi, Enrica, E-mail: enrica.borsi2@unibo.it [Department of Experimental Diagnostic and Specialty Medicine (DIMES), “L. and A. Seràgnoli”, Bologna University School of Medicine, S. Orsola' s University Hospital (Italy); Perrone, Giulia [Fondazione IRCCS Istituto Nazionale dei Tumori, Hematology Department, Via Venezian 1, 20133 Milano (Italy); Terragna, Carolina; Martello, Marina; Zamagni, Elena; Tacchetti, Paola; Pantani, Lucia; Brioli, Annamaria; Dico, Angela Flores; Zannetti, Beatrice Anna; Rocchi, Serena; Cavo, Michele [Department of Experimental Diagnostic and Specialty Medicine (DIMES), “L. and A. Seràgnoli”, Bologna University School of Medicine, S. Orsola' s University Hospital (Italy)

    2014-11-01

    Multiple myeloma (MM) is a malignant disorder of post-germinal center B cells, characterized by the clonal proliferation of malignant plasma cells (PCs) within the bone marrow (BM). The reciprocal and complex interactions that take place between the different compartments of BM and the MM cells result in tumor growth, angiogenesis, bone disease, and drug resistance. Given the importance of the BM microenvironment in MM pathogenesis, we investigated the possible involvement of Hypoxia-Inducible transcription Factor-1 alpha (HIF-1α) in the PCs-bone marrow stromal cells interplay. To test this hypothesis, we used EZN-2968, a 3rd generation antisense oligonucleotide against HIF-1α, to inhibit HIF-1α functions. Herein, we provide evidence that the interaction between MM cells and BM stromal cells is drastically reduced upon HIF-1α down-modulation. Notably, we showed that upon exposure to HIF-1α inhibitor, neither the incubation with IL-6 nor the co-culture with BM stromal cells were able to revert the anti-proliferative effect induced by EZN-2968. Moreover, we observed a down-modulation of cytokine-induced signaling cascades and a reduction of MM cells adhesion capability to the extracellular matrix proteins in EZN-2968-treated samples. Taken together, these results strongly support the concept that HIF-1α plays a critical role in the interactions between bone BM cells and PCs in Multiple Myeloma. - Highlights: • HIF-1α inhibition induces a mild apoptotic cell death. • Down-modulation of cytokine-induced signaling cascades upon HIF-1α inhibition. • Reduced interaction between MM cells and BMSCs upon HIF-1α down-modulation. • Reduced PCs adhesion to the extracellular matrix protein induced by EZN-2968. • HIF-1α inhibition may be an attractive therapeutic strategy for Multiple Myeloma.

  15. 64Cu-ATSM and 18FDG PET uptake and 64Cu-ATSM autoradiography in spontaneous canine tumors: comparison with pimonidazole hypoxia immunohistochemistry

    Directory of Open Access Journals (Sweden)

    Hansen Anders E

    2012-06-01

    Full Text Available Abstract Background The aim of this study was to compare 64Cu-diacetyl-bis(N4-methylsemicarbazone (64Cu-ATSM and 18FDG PET uptake characteristics and 64Cu-ATSM autoradiography to pimonidazole immunohistochemistry in spontaneous canine sarcomas and carcinomas. Methods Biopsies were collected from individual tumors between approximately 3 and 25 hours after the intravenous injection of 64Cu-ATSM and pimonidazole. 64Cu-ATSM autoradiography and pimonidazole immunostaining was performed on sectioned biopsies. Acquired 64Cu-ATSM autoradiography and pimonidazole images were rescaled, aligned and their distribution patterns compared. 64Cu-ATSM and 18FDG PET/CT scans were performed in a concurrent study and uptake characteristics were obtained for tumors where available. Results Maximum pimonidazole pixel value and mean pimonidazole labeled fraction was found to be strongly correlated to 18FDG PET uptake levels, whereas more varying results were obtained for the comparison to 64Cu-ATSM. In the case of the latter, uptake at scans performed 3 h post injection (pi generally showed strong positive correlated to pimonidazole uptake. Comparison of distribution patterns of pimonidazole immunohistochemistry and 64Cu-ATSM autoradiography yielded varying results. Significant positive correlations were mainly found in sections displaying a heterogeneous distribution of tracers. Conclusions Tumors with high levels of pimonidazole staining generally displayed high uptake of 18FDG and 64Cu-ATSM (3 h pi.. Similar regional distribution of 64Cu-ATSM and pimonidazole was observed in most heterogeneous tumor regions. However, tumor and hypoxia level dependent differences may exist with regard to the hypoxia specificity of 64Cu-ATSM in canine tumors.

  16. Hypoxia-increased RAGE and P2X7R expression regulates tumor cell invasion through phosphorylation of Erk1/2 and Akt and nuclear translocation of NF-{kappa}B.

    Science.gov (United States)

    Tafani, Marco; Schito, Luana; Pellegrini, Laura; Villanova, Lidia; Marfe, Gabriella; Anwar, Tahira; Rosa, Roberta; Indelicato, Manuela; Fini, Massimo; Pucci, Bruna; Russo, Matteo A

    2011-08-01

    The role of hypoxia in regulating tumor progression is still controversial. Here, we demonstrate that, similarly to what previously observed by us in human prostate and breast tumor samples, hypoxia increases expression of the receptor for advanced glycation end products (RAGE) and the purinergic receptor P2X7 (P2X7R). The role of hypoxia was shown by the fact that hypoxia-inducible factor (HIF)-1α silencing downregulated RAGE and P2X7R protein levels as well as nuclear factor-kappaB (NF-κB) expression. In contrast, NF-κB silencing reduced P2X7R expression without affecting RAGE protein levels or nuclear accumulation of HIF-1α. Treatment of hypoxic tumor cells with HMGB1 and BzATP ligands, respectively, of RAGE and P2X7R, activated a signaling pathway that, through Akt and Erk phosphorylation, determines nuclear accumulation of NF-κB and increases cell invasion. Inhibition of Akt by SH5 and Erk by INH1 prevented both nuclear translocation of NF-κB and cell invasion. Moreover, silencing RAGE and P2X7R abolished nuclear accumulation of NF-κB as well as cell invasion without affecting HIF-1α stabilization. Once in the nucleus, NF-κB would contribute to cell survival and invasion under hypoxia, by maintaining RAGE and P2X7R expression levels and matrix metalloproteinases 2 and 9 synthesis. These results show that, hypoxia can upregulate expression levels of membrane receptors that, by binding extracellular molecules eventually released by necrotic cells, contribute to the increased invasiveness of transformed tumor cells. Moreover, these observations strengthen our working hypothesis that upregulation of damage-associated molecular patterns receptors by HIF-1α represents the crucial event bridging hypoxia and inflammation in obtaining the malignant phenotype.

  17. Tumor hypoxia imaging in orthotopic liver tumors and peritoneal metastasis: a comparative study featuring dynamic 18F-MISO and 124I-IAZG PET in the same study cohort

    International Nuclear Information System (INIS)

    Riedl, Christopher C.; Brader, Peter; Hricak, Hedvig; Zanzonico, Pat; Humm, John L.; Reid, Vincent; Woo, Yanghee; Fong, Yuman; Wen, Bixiu; Ling, C.C.

    2008-01-01

    The purpose of this paper is to compare the uptake of two clinically promising positron emission tomography (PET) hypoxia targeting agents, 124 I-iodoazomycin galactopyranoside ( 124 I-IAZG) and 18 F-fluoromisonidazole ( 18 F-FMISO), by dynamic microPET imaging, in the same rats bearing liver tumors and peritoneal metastasis. Morris hepatoma (RH7777) fragments were surgically implanted into the livers of four nude rats. Tumors formed in the liver and disseminated into the peritoneal cavity. Each rat had a total of two to three liver tumors and peritoneal metastasis measuring 10-15 mm in size. Animals were injected with 18 F-FMISO, followed on the next day (upon complete 18 F decay) by 124 I-IAZG. The animals were imaged in list mode on the microPET system from the time of injection of each tracer for 3 h and then again at 6 h and 24 h for the long-lived 124 I-IAZG tracer (4.2-day half-life). Micro computed tomography (CT) scans of each rat were performed for co-registration with the microPET scans acquired with a liver contrast agent, allowing tumor identification. Regions of interest (ROIs) were drawn over the heart, liver, muscle, and the hottest areas of the tumors. Time-activity curves (TACs) were drawn for each tissue ROI. The 18 F-FMISO signal increased in tumors over the 3-h time course of observation. In contrast, after the initial injection, the 124 I-IAZG signal slowly and continuously declined in the tumors. Nevertheless, the tumor-to-normal-tissue ratios of 124 I-IAZG increased, but more slowly than those of 18 F-FMISO and as a result of the differentially faster clearance from the surrounding normal tissues. These pharmacokinetic patterns were seen in all 11 tumors of the four animals. 18 F-FMISO localizes in the same intra-tumor regions as 124 I-IAZG. The contrast ratios (tumor/background) reach similar values for the two hypoxia tracers, but at later times for 124 I-IAZG than for 18 F-FMISO and, therefore, with poorer count statistics. As a

  18. Hypoxia-inducible factor 1 alpha is a poor prognostic factor and potential therapeutic target in malignant peripheral nerve sheath tumor.

    Directory of Open Access Journals (Sweden)

    Suguru Fukushima

    Full Text Available Malignant peripheral nerve sheath tumor (MPNST is a rare soft tissue sarcoma with poor prognosis. Hypoxia-inducible factor 1 (HIF-1 plays a crucial role in the cellular response to hypoxia and regulates the expression of multiple genes involved in tumor progression in various cancers. However, the importance of the expression of HIF-1α in MPNSTs is unclear.The expression of HIF-1α was examined immunohistochemically in 82 MPNST specimens. Cell culture assays of human MPNST cells under normoxic and hypoxic conditions were used to evaluate the impact of anti-HIF-1α-specific siRNA inhibition on cell survival. A screening kit was employed to identify small molecules that inhibited HIF-1α.The nuclear expression of HIF-1α was positive in 75.6% of MPNST samples (62/82 cases. Positivity for HIF-1α was a significant poor prognostic factor both in univariate (P = 0.048 and multivariate (P ≤ 0.0001 analyses. HIF-1α knockdown abrogated MPNST cell growth, inducing apoptosis. Finally, chetomin, an inhibitor of HIF-1α, effectively inhibited the growth of MPNST cells and induced their apoptosis.Inhibition of HIF-1α signaling is a potential treatment option for MPNSTs.

  19. Experimental study of the correlation between 99Tcm-EC-MNZ SPECT imaging and the expression of hypoxia inducible factor-1α in tumor tissuse

    International Nuclear Information System (INIS)

    Chen Jie; Lu Xueguan; Tang Jun; Fan Wo

    2005-01-01

    Objective: To evaluate the correlation between 99 Tc m -ethylene dicysteinc-metronidazaole ( 99 Tc M -EC-MNZ) SPECT imaging and the expression of hypoxia inducible factor-1α (HIF-1α) in tumor tissue. Methods: Twelve S180 sarcoma-bearing Kunming mice tumor models were established. Hypoxic imaging was obtained by SPECT with 99 Tc m -EC-MNZ and the corresponding tumor/muscle ratios (T/M) were measured. Then the animals were sacrificed and the tumor specimen was resected, the expression of HIF-1α and vascular endothelial growth factor (VEGF) was measured by immunohistochemistry. Results: Three hours after injection of 99 Tc m -EC-MNZ, the T/M ranged from 1.93 to 4.46 (median 3.13). The expression of HIF-1α ranged from 31.2% to 60.8% (median 50.4%) and was linearly correlated with the T/M (t=2.732, r=0.654, P=0.021). The expression of VEGF ranged from 33.8% to 57.5% (median 53.1%) and also linearly correlated with the expression of HIF-1α (t=3.011, r=0.690, P=0.0131). Conclusions: There is linear correlation between 99 Tc m -EC-MNZ hypoxic SPECT imaging and the expression of HIF-1α. Combining them can reliably reflect the hypoxic status of the tumor. (authors)

  20. Mxd1 mediates hypoxia-induced cisplatin resistance in osteosarcoma cells by repression of the PTEN tumor suppressor gene.

    Science.gov (United States)

    Zheng, Datong; Wu, Weiling; Dong, Na; Jiang, Xiuqin; Xu, Jinjin; Zhan, Xi; Zhang, Zhengdong; Hu, Zhenzhen

    2017-10-01

    Hypoxia-induced chemoresistance remains a major obstacle to treating osteosarcoma effectively. Mxd1, a member of the Myc/Max/Mxd family, was shown to be involved in the development of drug resistance under hypoxia. However, the effect of Mxd1 on hypoxia-induced cisplatin (CDDP) resistance and its mechanism in osteosarcoma have not been fully elucidated. In this study, we demonstrated that HIF-1α-induced Mxd1 contributed to CDDP resistance in hypoxic U-2OS and MG-63 cells. The knockdown of Mxd1 expression elevated PTEN expression at both protein and RNA levels in these hypoxic cells. Using Luciferase reporter and ChIP assays, we confirmed that Mxd1 directly bound to the E-box sites within the PTEN promoter region. We further demonstrated that PTEN knockdown decreased CDDP sensitivity in Mxd1 siRNA-transfected U-2OS and MG-63 cells under hypoxia. Our results also showed that Mxd1 deficiency in hypoxic U-2OS and MG-63 cells lead to inactivation of PI3K/AKT signaling, which is the downstream of PTEN. Furthermore, blockade of PI3K/AKT signal re-sensitized hypoxic U-2OS and MG-63 cells to CDDP. Taken together, these findings suggest that HIF-1α-induced Mxd1 up-regulation suppresses the expression of PTEN under hypoxia, which leads to the activation of PI3K/AKT antiapoptotic and survival pathway. As a result CDDP resistance in osteosarcoma cells is induced. © 2017 Wiley Periodicals, Inc.

  1. Phase 1 Trial of Bevacizumab With Concurrent Chemoradiation Therapy for Squamous Cell Carcinoma of the Head and Neck With Exploratory Functional Imaging of Tumor Hypoxia, Proliferation, and Perfusion

    Energy Technology Data Exchange (ETDEWEB)

    Nyflot, Matthew J., E-mail: nyflot@uw.edu [Department of Radiation Oncology, University of Washington, Seattle, Washington (United States); Kruser, Tim J. [Department of Radiation Oncology, Cadence Cancer Center at Delnor Hospital, Geneva, Illinois (United States); Traynor, Anne M. [Department of Medicine, University of Wisconsin Carbone Cancer Center and School of Medicine and Public Health, Madison, Wisconsin (United States); Khuntia, Deepak [Varian Medical Systems, Palo Alto, California (United States); Yang, David T. [Departments of Pathology and Laboratory Medicine, University of Wisconsin Carbone Cancer Center and School of Medicine and Public Health, Madison, Wisconsin (United States); Hartig, Gregory K.; McCulloch, Timothy M. [Department of Surgery-Otolaryngology, H& N Surgery Division, University of Wisconsin Carbone Cancer Center and School of Medicine and Public Health, Madison, Wisconsin (United States); Wiederholt, Peggy A. [Department of Human Oncology, University of Wisconsin Carbone Cancer Center and School of Medicine and Public Health, Madison, Wisconsin (United States); Gentry, Lindell R. [Department of Radiology, University of Wisconsin Carbone Cancer Center and School of Medicine and Public Health, Madison, Wisconsin (United States); Hoang, Tien [Department of Medicine, University of Wisconsin Carbone Cancer Center and School of Medicine and Public Health, Madison, Wisconsin (United States); Jeraj, Robert [Department of Human Oncology, University of Wisconsin Carbone Cancer Center and School of Medicine and Public Health, Madison, Wisconsin (United States); Department of Radiology, University of Wisconsin Carbone Cancer Center and School of Medicine and Public Health, Madison, Wisconsin (United States); Department of Medical Physics, University of Wisconsin Carbone Cancer Center and School of Medicine and Public Health, Madison, Wisconsin (United States); and others

    2015-04-01

    Purpose: A phase 1 trial was completed to examine the safety and feasibility of combining bevacizumab with radiation and cisplatin in patients with locoregionally advanced squamous cell carcinoma of the head and neck (HNSCC) treated with curative intent. Additionally, we assessed the capacity of bevacizumab to induce an early tumor response as measured by a series of biological imaging studies. Methods and Materials: All patients received a single induction dose of bevacizumab (15 mg/kg) delivered 3 weeks (±3 days) before the initiation of chemoradiation therapy. After the initial dose of bevacizumab, comprehensive head and neck chemoradiation therapy was delivered with curative intent to 70 Gy in 33 fractions with concurrent weekly cisplatin at 30 mg/m{sup 2} and bevacizumab every 3 weeks (weeks 1, 4, 7) with dose escalation from 5 to 10 to 15 mg/kg. All patients underwent experimental imaging with [{sup 18}F]fluorothymidine positron emission tomography (FLT-PET) (proliferation), [{sup 61}Cu]Cu-diacetyl-bis(N4-methylthiosemicarbazone) PET (Cu-ATSM-PET) (hypoxia), and dynamic contrast-enhanced computed tomography (DCE-CT) (perfusion) at 3 time points: before bevacizumab monotherapy, after bevacizumab monotherapy, and during the combined therapy course. Results: Ten patients were enrolled. All had stage IV HNSCC, all achieved a complete response to treatment, and 9 of 10 remain alive, with a mean survival time of 61.3 months. All patients experienced grade 3 toxicity, but no dose-limiting toxicities or significant bleeding episodes were observed. Significant reductions were noted in tumor proliferation (FLT-PET), tumor hypoxia (Cu-ATSM-PET), and DCE-CT contrast enhancement after bevacizumab monotherapy, with further decreases in FLT-PET and Cu-ATSM-PET during the combined therapy course. Conclusions: The incorporation of bevacizumab into comprehensive chemoradiation therapy regimens for patients with HNSCC appears safe and feasible. Experimental imaging

  2. A Comparative Study of the Hypoxia PET Tracers [18F]HX4, [18F]FAZA, and [18F]FMISO in a Preclinical Tumor Model

    International Nuclear Information System (INIS)

    Peeters, Sarah G.J.A.; Zegers, Catharina M.L.; Lieuwes, Natasja G.; Elmpt, Wouter van; Eriksson, Jonas; Dongen, Guus A.M.S. van; Dubois, Ludwig; Lambin, Philippe

    2015-01-01

    Purpose: Several individual clinical and preclinical studies have shown the possibility of evaluating tumor hypoxia by using noninvasive positron emission tomography (PET). The current study compared 3 hypoxia PET tracers frequently used in the clinic, [ 18 F]FMISO, [ 18 F]FAZA, and [ 18 F]HX4, in a preclinical tumor model. Tracer uptake was evaluated for the optimal time point for imaging, tumor-to-blood ratios (TBR), spatial reproducibility, and sensitivity to oxygen modification. Methods and Materials: PET/computed tomography (CT) images of rhabdomyosarcoma R1-bearing WAG/Rij rats were acquired at multiple time points post injection (p.i.) with one of the hypoxia tracers. TBR values were calculated, and reproducibility was investigated by voxel-to-voxel analysis, represented as correlation coefficients (R) or Dice similarity coefficient of the high-uptake volume. Tumor oxygen modifications were induced by exposure to either carbogen/nicotinamide treatment or 7% oxygen breathing. Results: TBR was stabilized and maximal at 2 hours p.i. for [ 18 F]FAZA (4.0 ± 0.5) and at 3 hours p.i. for [ 18 F]HX4 (7.2 ± 0.7), whereas [ 18 F]FMISO showed a constant increasing TBR (9.0 ± 0.8 at 6 hours p.i.). High spatial reproducibility was observed by voxel-to-voxel comparisons and Dice similarity coefficient calculations on the 30% highest uptake volume for both [ 18 F]FMISO (R = 0.86; Dice coefficient = 0.76) and [ 18 F]HX4 (R = 0.76; Dice coefficient = 0.70), whereas [ 18 F]FAZA was less reproducible (R = 0.52; Dice coefficient = 0.49). Modifying the hypoxic fraction resulted in enhanced mean standardized uptake values for both [ 18 F]HX4 and [ 18 F]FAZA upon 7% oxygen breathing. Only [ 18 F]FMISO uptake was found to be reversible upon exposure to nicotinamide and carbogen. Conclusions: This study indicates that each tracer has its own strengths and, depending on the question to be answered, a different tracer can be put forward

  3. Hypoxia promotes uveal melanoma invasion through enhanced Notch and MAPK activation.

    Directory of Open Access Journals (Sweden)

    Laura Asnaghi

    Full Text Available The transcriptional response promoted by hypoxia-inducible factors has been associated with metastatic spread of uveal melanoma. We found expression of hypoxia-inducible factor 1α (HIF-1α protein in well-vascularized tumor regions as well as in four cell lines grown in normoxia, thus this pathway may be important even in well-oxygenated uveal melanoma cells. HIF-1α protein accumulation in normoxia was inhibited by rapamycin. As expected, hypoxia (1% pO2 further induced HIF-1α protein levels along with its target genes VEGF and LOX. Growth in hypoxia significantly increased cellular invasion of all 5 uveal melanoma lines tested, as did the introduction of an oxygen-insensitive HIF-1α mutant into Mel285 cells with low HIF-1α baseline levels. In contrast, HIF-1α knockdown using shRNA significantly decreased growth in hypoxia, and reduced by more than 50% tumor invasion in four lines with high HIF-1α baseline levels. Pharmacologic blockade of HIF-1α protein expression using digoxin dramatically suppressed cellular invasion both in normoxia and in hypoxia. We found that Notch pathway components, including Jag1-2 ligands, Hes1-Hey1 targets and the intracellular domain of Notch1, were increased in hypoxia, as well as the phosphorylation levels of Erk1-2 and Akt. Pharmacologic and genetic inhibition of Notch largely blocked the hypoxic induction of invasion as did the pharmacologic suppression of Erk1-2 activity. In addition, the increase in Erk1-2 and Akt phosphorylation by hypoxia was partially reduced by inhibiting Notch signaling. Our findings support the functional importance of HIF-1α signaling in promoting the invasive capacity of uveal melanoma cells in both hypoxia and normoxia, and suggest that pharmacologically targeting HIF-1α pathway directly or through blockade of Notch or Erk1-2 pathways can slow tumor spread.

  4. The Influence of Changes in Tumor Hypoxia on Dose-Painting Treatment Plans Based on 18F-FMISO Positron Emission Tomography

    International Nuclear Information System (INIS)

    Lin Zhixiong; Mechalakos, James; Nehmeh, Sadek; Schoder, Heiko; Lee, Nancy; Humm, John; Ling, C. Clifton

    2008-01-01

    Purpose: To evaluate how changes in tumor hypoxia, according to serial fluorine-18-labeled fluoro-misonidazole ( 18 F-FMISO) positron emission tomography (PET) imaging, affect the efficacy of intensity-modulated radiotherapy (IMRT) dose painting. Methods and Materials: Seven patients with head and neck cancers were imaged twice with FMISO PET, separated by 3 days, before radiotherapy. Intensity-modulated radiotherapy plans were designed, on the basis of the first FMISO scan, to deliver a boost dose of 14 Gy to the hypoxic volume, in addition to the 70-Gy prescription dose. The same plans were then applied to hypoxic volumes from the second FMISO scan, and the efficacy of dose painting evaluated by assessing coverage of the hypoxic volumes using D max , D min , D mean , D 95 , and equivalent uniform dose (EUD). Results: Similar hypoxic volumes were observed in the serial scans for 3 patients but dissimilar ones for the other 4. There was reduced coverage of hypoxic volumes of the second FMISO scan relative to that of the first scan (e.g., the average EUD decreased from 87 Gy to 80 Gy). The decrease was dependent on the similarity of the hypoxic volumes of the two scans (e.g., the average EUD decrease was approximately 4 Gy for patients with similar hypoxic volumes and approximately 12 Gy for patients with dissimilar ones). Conclusions: The changes in spatial distribution of tumor hypoxia, as detected in serial FMISO PET imaging, compromised the coverage of hypoxic tumor volumes achievable by dose-painting IMRT. However, dose painting always increased the EUD of the hypoxic volumes

  5. Successful tumour necrosis factor (TNF) blocking therapy suppresses oxidative stress and hypoxia-induced mitochondrial mutagenesis in inflammatory arthritis

    LENUS (Irish Health Repository)

    Biniecka, Monika

    2011-07-25

    Abstract Introduction To examine the effects of tumour necrosis factor (TNF) blocking therapy on the levels of early mitochondrial genome alterations and oxidative stress. Methods Eighteen inflammatory arthritis patients underwent synovial tissue oxygen (tpO2) measurements and clinical assessment of disease activity (DAS28-CRP) at baseline (T0) and three months (T3) after starting biologic therapy. Synovial tissue lipid peroxidation (4-HNE), T and B cell specific markers and synovial vascular endothelial growth factor (VEGF) were quantified by immunohistochemistry. Synovial levels of random mitochondrial DNA (mtDNA) mutations were assessed using Random Mutation Capture (RMC) assay. Results 4-HNE levels pre\\/post anti TNF-α therapy were inversely correlated with in vivo tpO2 (P < 0.008; r = -0.60). Biologic therapy responders showed a significantly reduced 4-HNE expression (P < 0.05). High 4-HNE expression correlated with high DAS28-CRP (P = 0.02; r = 0.53), tender joint count for 28 joints (TJC-28) (P = 0.03; r = 0.49), swollen joint count for 28 joints (SJC-28) (P = 0.03; r = 0.50) and visual analogue scale (VAS) (P = 0.04; r = 0.48). Strong positive association was found between the number of 4-HNE positive cells and CD4+ cells (P = 0.04; r = 0.60), CD8+ cells (P = 0.001; r = 0.70), CD20+ cells (P = 0.04; r = 0.68), CD68+ cells (P = 0.04; r = 0.47) and synovial VEGF expression (P = 0.01; r = 063). In patients whose in vivo tpO2 levels improved post treatment, significant reduction in mtDNA mutations and DAS28-CRP was observed (P < 0.05). In contrast in those patients whose tpO2 levels remained the same or reduced at T3, no significant changes for mtDNA mutations and DAS28-CRP were found. Conclusions High levels of synovial oxidative stress and mitochondrial mutation burden are strongly associated with low in vivo oxygen tension and synovial inflammation. Furthermore these significant mitochondrial genome alterations are rescued following successful anti TNF

  6. Conversion of Stationary to Invasive Tumor Initiating Cells (TICs): Role of Hypoxia in Membrane Type 1-Matrix Metalloproteinase (MT1-MMP) Trafficking

    Science.gov (United States)

    Li, Jian; Zucker, Stanley; Pulkoski-Gross, Ashleigh; Kuscu, Cem; Karaayvaz, Mihriban; Ju, Jingfang; Yao, Herui; Song, Erwei; Cao, Jian

    2012-01-01

    Emerging evidence has implicated the role of tumor initiating cells (TICs) in the process of cancer metastasis. The mechanism underlying the conversion of TICs from stationary to invasive remains to be characterized. In this report, we employed less invasive breast cancer TICs, SK-3rd, that displays CD44high/CD24low with high mammosphere-forming and tumorigenic capacities, to investigate the mechanism by which stationary TICs are converted to invasive TICs. Invasive ability of SK-3rd TICs was markedly enhanced when the cells were cultured under hypoxic conditions. Given the role of membrane type 1-matrix metalloproteinase (MT1-MMP) in cancer invasion/metastasis, we explored a possible involvement of MT1-MMP in hypoxia-induced TIC invasion. Silencing of MT1-MMP by a shRNA approach resulted in diminution of hypoxia-induced cell invasion in vitro and metastasis in vivo. Under hypoxic conditions, MT1-MMP redistributed from cytoplasmic storage pools to the cell surface of TICs, which coincides with the increased cell invasion. In addition, CD44, a cancer stem-like cell marker, inversely correlated with increased cell surface MT1-MMP. Interestingly, cell surface MT1-MMP gradually disappeared when the hypoxia-treated cells were switched to normoxia, suggesting the plasticity of TICs in response to oxygen content. Furthermore, we dissected the pathways leading to upregulated MT1-MMP in cytoplasmic storage pools under normoxic conditions, by demonstrating a cascade involving Twist1-miR10b-HoxD10 leading to enhanced MT1-MMP expression in SK-3rd TICs. These observations suggest that MT1-MMP is a key molecule capable of executing conversion of stationary TICs to invasive TICs under hypoxic conditions and thereby controlling metastasis. PMID:22679501

  7. Hypoxia Room

    Data.gov (United States)

    Federal Laboratory Consortium — The Hypoxia Room is a 8x8x8 ft. clear vinyl plastic and aluminum frame construction enclosure located within USAREIM laboratory 028. The Hypoxia Room (manufactured...

  8. Tumor microenvironment conditions alter Akt and Na+/H+ exchanger NHE1 expression in endothelial cells more than hypoxia alone

    DEFF Research Database (Denmark)

    Pedersen, Anna-Kathrine; Mendes Lopes de Melo, Joana; Mørup, Nina

    2017-01-01

    -ADP-ribose polymerase (PARP) cleavage consistent with inhibition of proliferation and induction of apoptosis. NHE1 knockdown, mimicking the effect of TME on NHE1 expression, reduced Ea.hy926 migration. TME effects on HIF-1α, VEGF, Akt, translation, proliferation or apoptosis markers were unaffected by NHE1 knockdown...... conditions. Here, we compared the effects of hypoxia and TME conditions on regulation of the Na+/H+ exchanger NHE1, Ser/Thr kinases Akt1–3, and downstream effectors in endothelial cells. Methods Human umbilical vein endothelial cells (HUVEC) and Ea.hy926 endothelial cells were exposed to simulated TME (1......% hypoxia, low serum, glucose, pH, high lactate) or 1% hypoxia for 24 or 48 h, with or without NHE1 inhibition or siRNA-mediated knockdown. mRNA and protein levels of NHE1, Akt1–3, and downstream effectors were assessed by qPCR and Western blotting, vascular endothelial growth factor (VEGF) release by ELISA...

  9. Copper-64-diacetyl-bis(N(4)-methylthiosemicarbazone) Pharmacokinetics in FaDu Xenograft Tumors and Correlation With Microscopic Markers of Hypoxia

    International Nuclear Information System (INIS)

    McCall, Keisha C.; Humm, John L.; Bartlett, Rachel; Reese, Megan; Carlin, Sean

    2012-01-01

    Purpose: The behavior of copper-64-diacetyl-bis(N(4)-methylthiosemicarbazone) ( 64 Cu-ATSM) in hypoxic tumors was examined through a combination of in vivo dynamic positron emission tomography (PET) and ex vivo autoradiographic and histologic evaluation using a xenograft model of head-and-neck squamous cell carcinoma. Methods and Materials: 64 Cu-ATSM was administered during dynamic PET imaging, and temporal changes in 64 Cu-ATSM distribution within tumors were evaluated for at least 1 hour and up to 18 hours. Animals were sacrificed at either 1 hour (cohort A) or after 18 hours (cohort B) postinjection of radiotracer and autoradiography performed. Ex vivo analysis of microenvironment subregions was conducted by immunohistochemical staining for markers of hypoxia (pimonidazole hydrochloride) and blood flow (Hoechst-33342). Results: Kinetic analysis revealed rapid uptake of radiotracer by tumors. The net influx (K i ) constant was 12-fold that of muscle, whereas the distribution volume (V d ) was 5-fold. PET images showed large tumor-to-muscle ratios, which continually increased over the entire 18-hour course of imaging. However, no spatial changes in 64 Cu-ATSM distribution occurred in PET imaging at 20 minutes postinjection. Microscopic intratumoral distribution of 64 Cu-ATSM and pimonidazole were not correlated at 1 hour or after 18 hours postinjection, nor was 64 Cu-ATSM and Hoechst-33342. Conclusions: The oxygen partial pressures at which 64 Cu-ATSM and pimonidazole are reduced and bound in cells are theorized to be distinct and separable. However, this study demonstrated that microscopic distributions of these tracers within tumors are independent. Researchers have shown 64 Cu-ATSM uptake to be specific to malignant expression, and this work has also demonstrated clear tumor targeting by the radiotracer.

  10. Copper-64-diacetyl-bis(N(4)-methylthiosemicarbazone) pharmacokinetics in FaDu xenograft tumors and correlation with microscopic markers of hypoxia.

    Science.gov (United States)

    McCall, Keisha C; Humm, John L; Bartlett, Rachel; Reese, Megan; Carlin, Sean

    2012-11-01

    The behavior of copper-64-diacetyl-bis(N(4)-methylthiosemicarbazone) ((64)Cu-ATSM) in hypoxic tumors was examined through a combination of in vivo dynamic positron emission tomography (PET) and ex vivo autoradiographic and histologic evaluation using a xenograft model of head-and-neck squamous cell carcinoma. (64)Cu-ATSM was administered during dynamic PET imaging, and temporal changes in (64)Cu-ATSM distribution within tumors were evaluated for at least 1 hour and up to 18 hours. Animals were sacrificed at either 1 hour (cohort A) or after 18 hours (cohort B) postinjection of radiotracer and autoradiography performed. Ex vivo analysis of microenvironment subregions was conducted by immunohistochemical staining for markers of hypoxia (pimonidazole hydrochloride) and blood flow (Hoechst-33342). Kinetic analysis revealed rapid uptake of radiotracer by tumors. The net influx (K(i)) constant was 12-fold that of muscle, whereas the distribution volume (V(d)) was 5-fold. PET images showed large tumor-to-muscle ratios, which continually increased over the entire 18-hour course of imaging. However, no spatial changes in (64)Cu-ATSM distribution occurred in PET imaging at 20 minutes postinjection. Microscopic intratumoral distribution of (64)Cu-ATSM and pimonidazole were not correlated at 1 hour or after 18 hours postinjection, nor was (64)Cu-ATSM and Hoechst-33342. The oxygen partial pressures at which (64)Cu-ATSM and pimonidazole are reduced and bound in cells are theorized to be distinct and separable. However, this study demonstrated that microscopic distributions of these tracers within tumors are independent. Researchers have shown (64)Cu-ATSM uptake to be specific to malignant expression, and this work has also demonstrated clear tumor targeting by the radiotracer. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. A 26-Gene Hypoxia Signature Predicts Benefit from Hypoxia-Modifying Therapy in Laryngeal Cancer but Not Bladder Cancer

    NARCIS (Netherlands)

    Eustace, A.; Mani, N.; Span, P.N.; Irlam, J.J.; Taylor, J.; Betts, G.N.; Denley, H.; Miller, C.J.; Homer, J.J.; Rojas, A.M.; Hoskin, P.J.; Buffa, F.M.; Harris, A.L.; Kaanders, J.H.A.M.; West, C.M.

    2013-01-01

    PURPOSE: Tumor hypoxia is associated with a poor prognosis, hypoxia modification improves outcome, and hypoxic status predicts benefit from treatment. Yet, there is no universal measure of clinical hypoxia. The aim of this study was to investigate whether a 26-gene hypoxia signature predicted

  12. Block of purinergic P2X7R inhibits tumor growth in a C6 glioma brain tumor animal model.

    Science.gov (United States)

    Ryu, Jae K; Jantaratnotai, Nattinee; Serrano-Perez, Maria C; McGeer, Patrick L; McLarnon, James G

    2011-01-01

    We examined the expression and pharmacological modulation of the purinergic receptor P2X7R in a C6 glioma model. Intrastriatal injection of C6 cells induced a time-dependent growth of tumor; at 2 weeks postinjection immunohistochemical analysis demonstrated higher levels of P2X7R in glioma-injected versus control vehicle-injected brains. P2X7R immunoreactivity colocalized with tumor cells and microglia, but not endogenous astrocytes. Intravenous administration of the P2X7R antagonist brilliant blue G (BBG) inhibited tumor growth in a spatially dependent manner from the C6 injection site. Treatment with BBG reduced tumor volume by 52% versus that in controls. Double immunostaining indicated that BBG treatment did not alter microgliosis, astrogliosis, or vasculature vessels in C6-injected animals. In vitro, BBG reduced the expression of P2X7R and glioma chemotaxis induced by the P2X7R ligand, 2',3'-O-(4-benzoyl-benzoyl)adenosine triphosphate (BzATP). Immunohistochemical staining of human glioblastoma tissue samples demonstrated greater expression of P2X7R compared to control nontumor samples. These results suggest that the efficacy of BBG in inhibiting tumor growth is primarily mediated by direct actions of the compound on P2X7R in glioma cells and that pharmacological inhibition of this purinergic receptor might serve as a strategy to slow the progression of brain tumors.

  13. Cimetidine inhibits salivary gland tumor cell adhesion to neural cells and induces apoptosis by blocking NCAM expression

    Directory of Open Access Journals (Sweden)

    Sakashita Hideaki

    2008-12-01

    Full Text Available Abstract Background Cimetidine, a histamine type-2 receptor antagonist, has been reported to inhibit the growth of glandular tumors such as colorectal cancer, however the mechanism of action underlying this effect is unknown. Adenoid cystic carcinoma is well known as a malignant salivary gland tumor which preferentially invades neural tissues. We demonstrated previously that human salivary gland tumor (HSG cells spontaneously express neural cell adhesion molecule (NCAM, that HSG cell proliferation may be controlled via a homophilic (NCAM-NCAM binding mechanism and that NCAM may be associated with perineural invasion by malignant salivary gland tumors. We further demonstrated that cimetidine inhibited NCAM expression and induced apoptosis in HSG cells. Here, we investigated the effects of cimetidine on growth and perineural/neural invasion of salivary gland tumor cells. Methods In this study, we have examined the effect of cimetidine on cancer cell adhesion to neural cells in vitro, one of the critical steps of cancer invasion and metastasis. We have also used an in vivo carcinogenesis model to confirm the effect of cimetidine. Results We have demonstrated for the first time that cimetidine can block the adhesion of HSG cells to neural cell monolayers and that it can also induce significant apoptosis in the tumor mass in a nude mouse model. We also demonstrated that these apoptotic effects of cimetidine might occur through down-regulation of the cell surface expression of NCAM on HSG cells. Cimetidine-mediated down-regulation of NCAM involved suppression of the nuclear translocation of NF-κB, a transcriptional activator of NCAM gene expression. Conclusion These findings suggest that growth and perineural/neural invasion of salivary gland tumors can be blocked by administration of cimetidine via induction of apoptosis and in which NCAM plays a role.

  14. Tumor hypoxia and microscopic diffusion capacity in brain tumors: A comparison of {sup 62}Cu-Diacetyl-Bis (N4-Methylthiosemicarbazone) PET/CT and diffusion-weighted MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Hino-Shishikura, Ayako; Tateishi, Ukihide; Shibata, Hirofumi; Yoneyama, Tomohiro; Nishii, Toshiaki; Torii, Ikuo; Inoue, Tomio [Graduate School of Medicine, Yokohama City University, Department of Radiology, Yokohama (Japan); Tateishi, Kensuke; Ohtake, Makoto; Kawahara, Nobutaka [Graduate School of Medicine, Yokohama City University, Department of Neurosurgery, Yokohama (Japan)

    2014-07-15

    The aim of this study was to clarify the relationship between tumor hypoxia and microscopic diffusion capacity in primary brain tumors using {sup 62}Cu-Diacetyl-Bis (N4-Methylthiosemicarbazone) ({sup 62}Cu-ATSM) PET/CT and diffusion-weighted MR imaging (DWI). This study was approved by the institutional human research committee and was HIPAA compliant, and informed consent was obtained from all patients. {sup 62}Cu-ATSM PET/CT and DWI were performed in a total of 40 primary brain tumors of 34 patients with low grade glioma (LGG, n = 13), glioblastoma (GBM, n = 20), and primary central nervous system lymphoma (PCNSL, n = 7). {sup 62}Cu-ATSM PET/CT parameters and apparent diffusion coefficient (ADC) obtained by DWI were compared. High intensity signals by {sup 62}Cu-ATSM PET/CT and DWI in patients with GBM and PCNSL, and low intensity signals in LGG patients were observed. An inverse correlation was found between maximum SUV (SUV{sub max}) and minimum ADC (ADC{sub min}) (r = -0.583, p < 0.0001), and between tumor/brain ratio (T/B{sub ratio}) and ADC{sub min} for all tumors (r = -0.532, p < 0.0001). Both SUV{sub max} and T/B{sub ratio} in GBM were higher than LGG (p < 0.0001 and p < 0.0001), and those in PCNSL were also higher than GBM (p = 0.033 and p = 0.044). The ADC{sub min} was lower in GBM (p = 0.011) and PCNSL (p = 0.01) than in LGG, while no significant difference was found between GBM and PCNSL (p = 0.90). Tumor hypoxia assessed by {sup 62}Cu-ATSM PET/CT correlated with microscopic diffusion capacity obtained by DWI in brain tumors. Both {sup 62}Cu-ATSM PET/CT and DWI were considered feasible imaging methods for grading glioma. However, {sup 62}Cu-ATSM PET/CT provided additional diagnostic information to differentiate between GBM and PCNSL. (orig.)

  15. Butylated Hydroxyanisole Blocks the Occurrence of Tumor Associated Macrophages in Tobacco Smoke Carcinogen-Induced Lung Tumorigenesis

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yan; Choksi, Swati; Liu, Zheng-Gang, E-mail: zgliu@helix.nih.gov [Cell and Cancer Biology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 (United States)

    2013-12-04

    Tumor-associated macrophages (TAMs) promote tumorigenesis because of their proangiogenic and immune-suppressive functions. Here, we report that butylated hydroxyanisole (BHA) blocks occurrence of tumor associated macrophages (TAMs) in tobacco smoke carcinogen-induced lung tumorigenesis. Continuous administration of butylated hydroxyanisole (BHA), a ROS inhibitor, before or after NNK treatment significantly blocked tumor development, although less effectively when BHA is administered after NNK treatment. Strikingly, BHA abolished the occurrence of F4/80{sup +} macrophages with similar efficiency no matter whether it was administered before or after NNK treatment. Detection of cells from bronchioalveolar lavage fluid (BALF) confirmed that BHA markedly inhibited the accumulation of macrophages while slightly reducing the number of lymphocytes that were induced by NNK. Immunohistological staining showed that BHA specifically abolished the occurrence of CD206{sup +} TAMs when it was administered before or after NNK treatment. Western blot analysis of TAMs markers, arginase I and Ym-1, showed that BHA blocked NNK-induced TAMs accumulation. Our study clearly demonstrated that inhibiting the occurrence of TAMs by BHA contributes to the inhibition of tobacco smoke carcinogen-induced tumorigenesis, suggesting ROS inhibitors may serve as a therapeutic target for treating smoke-induced lung cancer.

  16. Butylated Hydroxyanisole Blocks the Occurrence of Tumor Associated Macrophages in Tobacco Smoke Carcinogen-Induced Lung Tumorigenesis

    Directory of Open Access Journals (Sweden)

    Yan Zhang

    2013-12-01

    Full Text Available Tumor-associated macrophages (TAMs promote tumorigenesis because of their proangiogenic and immune-suppressive functions. Here, we report that butylated hydroxyanisole (BHA blocks occurrence of tumor associated macrophages (TAMs in tobacco smoke carcinogen-induced lung tumorigenesis. Continuous administration of butylated hydroxyanisole (BHA, a ROS inhibitor, before or after NNK treatment significantly blocked tumor development, although less effectively when BHA is administered after NNK treatment. Strikingly, BHA abolished the occurrence of F4/80+ macrophages with similar efficiency no matter whether it was administered before or after NNK treatment. Detection of cells from bronchioalveolar lavage fluid (BALF confirmed that BHA markedly inhibited the accumulation of macrophages while slightly reducing the number of lymphocytes that were induced by NNK. Immunohistological staining showed that BHA specifically abolished the occurrence of CD206+ TAMs when it was administered before or after NNK treatment. Western blot analysis of TAMs markers, arginase I and Ym-1, showed that BHA blocked NNK-induced TAMs accumulation. Our study clearly demonstrated that inhibiting the occurrence of TAMs by BHA contributes to the inhibition of tobacco smoke carcinogen-induced tumorigenesis, suggesting ROS inhibitors may serve as a therapeutic target for treating smoke-induced lung cancer.

  17. Hypoxia, HIF-1 Regulation and Cancer Therapy

    NARCIS (Netherlands)

    Groot, A.J.

    2008-01-01

    Oxygen insufficiency (hypoxia) is a common feature of human cancer and associated with tumor aggressiveness and poor clinical outcome. Furthermore, hypoxic tumors are more resistant to ionizing radiation and chemotherapy contributing to their unfavorable prognosis. The oxygen sensing pathway is

  18. EPR oxygen imaging and hyperpolarized (13) C MRI of pyruvate metabolism as noninvasive biomarkers of tumor treatment response to a glycolysis inhibitor 3-bromopyruvate

    DEFF Research Database (Denmark)

    Matsumoto, Shingo; Saito, Keita; Yasui, Hironobu

    2013-01-01

    The hypoxic nature of tumors results in treatment resistance and poor prognosis. To spare limited oxygen for more crucial pathways, hypoxic cancerous cells suppress mitochondrial oxidative phosphorylation and promote glycolysis for energy production. Thereby, inhibition of glycolysis has...... the potential to overcome treatment resistance of hypoxic tumors. Here, EPR imaging was used to evaluate oxygen dependent efficacy on hypoxia-sensitive drug. The small molecule 3-bromopyruvate blocks glycolysis pathway by inhibiting hypoxia inducible enzymes and enhanced cytotoxicity of 3-bromopyruvate under...

  19. Hypoxia activated EGFR signaling induces epithelial to mesenchymal transition (EMT.

    Directory of Open Access Journals (Sweden)

    Ashish Misra

    Full Text Available Metastasis is a multi-step process which requires the conversion of polarized epithelial cells to mesenchymal cells, Epithelial-Mesenchymal Transition (EMT. EMT is essential during embryonic morphogenesis and has been implicated in the progression of primary tumors towards metastasis. Hypoxia is known to induce EMT; however the molecular mechanism is still poorly understood. Using the A431 epithelial cancer cell line, we show that cells grown under hypoxic conditions migrated faster than cells grown under normal oxygen environment. Cells grown under hypoxia showed reduced adhesion to the extracellular matrix (ECM probably due to reduced number of Vinculin patches. Growth under hypoxic conditions also led to down regulation of E-cadherin and up regulation of vimentin expression. The increased motility of cells grown under hypoxia could be due to redistribution of Rac1 to the plasma membrane as opposed to increased expression of Rac1. EGF (Epidermal Growth Factor is a known inducer of EMT and growth of A431 cells in the absence of oxygen led to increased expression of EGFR (EGF Receptor. Treatment of A431 cells with EGF led to reduced cell adhesion to ECM, increased cell motility and other EMT characteristics. Furthermore, this transition was blocked by the monoclonal antibody Cetuximab. Cetuximab also blocked the hypoxia-induced EMT suggesting that cell growth under hypoxic conditions led to activation of EGFR signaling and induction of EMT phenotype.

  20. Apoptosis-induced ectodomain shedding of hypoxia-regulated carbonic anhydrase IX from tumor cells: a double-edged response to chemotherapy

    International Nuclear Information System (INIS)

    Vidlickova, Ivana; Dequiedt, Franck; Jelenska, Lenka; Sedlakova, Olga; Pastorek, Michal; Stuchlik, Stanislav; Pastorek, Jaromir; Zatovicova, Miriam; Pastorekova, Silvia

    2016-01-01

    Carbonic anhydrase IX (CA IX) is a tumor-associated, highly active, transmembrane carbonic anhydrase isoform regulated by hypoxia and implicated in pH control and adhesion-migration-invasion. CA IX ectodomain (ECD) is shed from the tumor cell surface to serum/plasma of patients, where it can signify cancer prognosis. We previously showed that the CA IX ECD release is mediated by disintegrin and metalloproteinase ADAM17. Here we investigated the CA IX ECD shedding in tumor cells undergoing apoptosis in response to cytotoxic drugs, including cycloheximide and doxorubicin. Presence of cell surface CA IX was correlated to the extent of apoptosis by flow cytometry in cell lines with natural or ectopic CA IX expression. CA IX ECD level was assessed by ELISA using CA IX-specific monoclonal antibodies. Effect of recombinant CA IX ECD on the activation of molecular pathways was evaluated using the cell-based dual-luciferase reporter assay. We found a significantly lower occurrence of apoptosis in the CA IX-positive cell subpopulation than in the CA IX-negative one. We also demonstrated that the cell-surface CA IX level dropped during the death progress due to an increased ECD shedding, which required a functional ADAM17. Inhibitors of metalloproteinases reduced CA IX ECD shedding, but not apoptosis. The CA IX ECD release induced by cytotoxic drugs was connected to elevated expression of CA IX in the surviving fraction of cells. Moreover, an externally added recombinant CA IX ECD activated a pathway driven by the Nanog transcription factor implicated in epithelial-mesenchymal transition and stemness. These findings imply that the increased level of the circulating CA IX ECD might be useful as an indicator of an effective antitumor chemotherapy. Conversely, elevated CA IX ECD might generate unwanted effects through autocrine/paracrine signaling potentially contributing to resistance and tumor progression

  1. Imaging Hypoxia in Xenografted and Murine Tumors with 18F-Fluoroazomycin Arabinoside: A Comparative Study Involving microPET, Autoradiography, pO2-Polarography, and Fluorescence Microscopy

    DEFF Research Database (Denmark)

    Busk, Morten; Horsman, Michael R; Jakobsen, Steen

    2008-01-01

    PURPOSE: Positron emission tomography (PET) allows noninvasive assessment of tumor hypoxia; however the combination of low resolution and slow tracer clearance from nonhypoxic tissue is problematic. The aim of this study was to examine the in vivo hypoxia selectivity of fluoroazomycin arabinoside...... ([(18)F]-FAZA), a promising tracer with improved washout kinetics from oxygenated tissue. METHODS AND MATERIALS: Three squamous cell carcinomas and one fibrosarcoma with widely differing spatial patterns of vascularization, hypoxia, and necrosis were grown in mice and evaluated with PET...... and an inverse correlation (except for the fibrosarcoma) between the distribution of [(18)F]-FAZA and Hoechst dye. Moreover intratumoral heterogeneity in tracer distribution was clearly visible on autoradiograms, with a [(18)F]-FAZA concentration approximately six times higher in poorly oxygenated areas than...

  2. Disrupting glucose-6-phosphate isomerase fully suppresses the "Warburg effect" and activates OXPHOS with minimal impact on tumor growth except in hypoxia.

    Science.gov (United States)

    de Padua, Monique Cunha; Delodi, Giulia; Vučetić, Milica; Durivault, Jérôme; Vial, Valérie; Bayer, Pascale; Noleto, Guilhermina Rodrigues; Mazure, Nathalie M; Ždralević, Maša; Pouysségur, Jacques

    2017-10-20

    As Otto Warburg first observed, cancer cells largely favor fermentative glycolysis for growth even under aerobic conditions. This energy paradox also extends to rapidly growing normal cells indicating that glycolysis is optimal for fast growth and biomass production. Here we further explored this concept by genetic ablation of fermentative glycolysis in two fast growing cancer cell lines: human colon adenocarcinoma LS174T and B16 mouse melanoma. We disrupted the upstream glycolytic enzyme, glucose-6-phosphate isomerase ( GPI ), to allow cells to re-route glucose-6-phosphate flux into the pentose-phosphate branch. Indeed, GPI -KO severely reduced glucose consumption and suppressed lactic acid secretion, which reprogrammed these cells to rely on oxidative phosphorylation and mitochondrial ATP production to maintain viability. In contrast to previous pharmacological inhibition of glycolysis that suppressed tumor growth, GPI -KO surprisingly demonstrated only a moderate impact on normoxic cell growth. However, hypoxic (1% O 2 ) cell growth was severely restricted. Despite in vitro growth restriction under hypoxia, tumor growth rates in vivo were reduced less than 2-fold for both GPI -KO cancer cell lines. Combined our results indicate that exclusive use of oxidative metabolism has the capacity to provide metabolic precursors for biomass synthesis and fast growth. This work and others clearly indicate that metabolic cancer cell plasticity poses a strong limitation to anticancer strategies.

  3. Efficient inhibition of tumor angiogenesis and growth by a synthetic peptide blocking S100A4-methionine aminopeptidase 2 interaction

    Directory of Open Access Journals (Sweden)

    Takahiro Ochiya

    Full Text Available The prometastatic calcium-binding protein, S100A4, is expressed in endothelial cells, and its downregulation markedly suppresses tumor angiogenesis in a xenograft cancer model. Given that endothelial S100A4 can be a molecular target for inhibiting tumor angiogenesis, we addressed here whether synthetic peptide capable of blocking S100A4-effector protein interaction could be a novel antiangiogenic agent. To examine this hypothesis, we focused on the S100A4-binding domain of methionine aminopeptidase 2, an effector protein, which plays a role in endothelial cell growth. Overexpression of the domain in mouse endothelial MSS31 cells reduced DNA synthesis, and the corresponding synthetic peptide (named NBD indeed interacted with S100A4 and inhibited capillary formation in vitro and new blood vessel formation in vivo. Intriguingly, a single intra-tumor administration of the NBD peptide in human prostate cancer xenografts significantly reduced vascularity, resulting in tumor regression. Mechanistically, the NBD peptide enhanced assembly of nonmuscle myosin IIA filaments along with Ser1943 phosphorylation, stimulated formation of focal adhesions without phosphorylation of focal adhesion kinase, and provoked G1/S arrest of the cell cycle. Altogether, the NBD peptide is a potent inhibitor for tumor angiogenesis, and is the first example of an anticancer peptide drug developed on the basis of an endothelial S100A4-targeted strategy.

  4. Efficient inhibition of tumor angiogenesis and growth by a synthetic peptide blocking S100A4-methionine aminopeptidase 2 interaction.

    Science.gov (United States)

    Ochiya, Takahiro; Takenaga, Keizo; Asagiri, Masataka; Nakano, Kazumi; Satoh, Hitoshi; Watanabe, Toshiki; Imajoh-Ohmi, Shinobu; Endo, Hideya

    2015-01-01

    The prometastatic calcium-binding protein, S100A4, is expressed in endothelial cells, and its downregulation markedly suppresses tumor angiogenesis in a xenograft cancer model. Given that endothelial S100A4 can be a molecular target for inhibiting tumor angiogenesis, we addressed here whether synthetic peptide capable of blocking S100A4-effector protein interaction could be a novel antiangiogenic agent. To examine this hypothesis, we focused on the S100A4-binding domain of methionine aminopeptidase 2, an effector protein, which plays a role in endothelial cell growth. Overexpression of the domain in mouse endothelial MSS31 cells reduced DNA synthesis, and the corresponding synthetic peptide (named NBD) indeed interacted with S100A4 and inhibited capillary formation in vitro and new blood vessel formation in vivo. Intriguingly, a single intra-tumor administration of the NBD peptide in human prostate cancer xenografts significantly reduced vascularity, resulting in tumor regression. Mechanistically, the NBD peptide enhanced assembly of nonmuscle myosin IIA filaments along with Ser1943 phosphorylation, stimulated formation of focal adhesions without phosphorylation of focal adhesion kinase, and provoked G1/S arrest of the cell cycle. Altogether, the NBD peptide is a potent inhibitor for tumor angiogenesis, and is the first example of an anticancer peptide drug developed on the basis of an endothelial S100A4-targeted strategy.

  5. The integrin-linked kinase gene up-regulated by hypoxia plays its pro-survival role in colorectal cancer cells.

    Science.gov (United States)

    Xiao, Lei; Yue, Xiaolong; Ming, Xiaodong; Xu, Lishan; Ding, Mingfeng; Xu, Jun; Liu, Qian

    2014-02-01

    Colorectal cancer (CRC) is a leading cause of cancer death in recent years. It is believed that there are hypoxic regions in both early and advanced stage of tumor and hypoxia is able to reinforce the aggressiveness of tumor cells and accelerate the progression of cancer. Until now the mechanisms by which hypoxia promotes the progression of CRC are far from well understood. Integrin-linked kinase (ILK) is a crucial mediator and over-expressed in CRC patients. But whether ILK is involved in the process that hypoxia promotes CRC cells growth and silencing the ILK gene results in CRC cells apoptosis is not clear. Lentivirus transfection, invasion assay, TUNEL assay, Bromodeoxyuridine incorporation and mitochondrial function assay were applied to demonstrate our hypothesis. In this study, we found that hypoxia induced the expression of ILK in a time-dependent manner, and after knocking down ILK expression with ILK shRNA, the cells proliferation promoted by hypoxia was inhibited in HT29 cell line. Moreover, blocking the ILK pathway led to caspase-3 and caspase-9 activations, the decrease of mitochondrial membrane potential, and cells apoptosis. And the inhibitory effects of hypoxia on cells apoptosis were mediated by the ILK pathway. In addition, hypoxia promoted HT29 cells metastasis and invasion through the ILK pathway. Therefore, we conclude that the CRC cells survival and invasion enhanced by hypoxia are mediated by ILK, and ILK may be an important potential therapeutic target for CRC.

  6. Tumor-Endothelium Cross Talk Blocks Recruitment of Neutrophils to Endothelial Cells: A Novel Mechanism of Endothelial Cell Anergy

    Directory of Open Access Journals (Sweden)

    Roman A. Blaheta

    2009-10-01

    Full Text Available Tumor cells have evolved effective strategies to escape the host immune response. The objective of this study was to determine whether tumor cells can condition endothelial cells in a specific manner to prevent subsequent adhesion of polymorphonuclear neutrophils (PMNs and/or peripheral blood lymphocytes (PBLs. Human umbilical vein endothelial cells (HUVECs and UKF-NB-4 neuroblastoma tumor cells were established in coculture on opposite sides of porous transwell filters. After 24 hours with and without HUVEC conditioning, PMNs or PBLs were added to the HUVEC monolayer. Adhesion to conditioned HUVEC versus adhesion to nonconditioned HUVEC was compared. Effects on endothelial CD44v4, CD44v5, CD44v7, intercellular adhesion molecule 1 (ICAM-1, E-selectin, and vascular cell adhesion molecule 1 (VCAM-1 adhesion receptor expression were analyzed by flow cytometry, intracellular signaling proteins of the mitogen-activated protein kinase pathway and protein kinase C (PKC subtypes quantified by Western blot analysis. Endothelial conditioning led to a distinct reduction in PMN but not in PBL adhesion to HUVEC. CD44 was significantly reduced, whereas ICAM-1, E-selectin, and VCAM-1 were not altered during HUVEC conditioning. Antibody blockade against CD44v4, CD44v5, and CD44v7 inhibited PMN but not PBL binding. The observed effects were caused by direct tumor cell-HUVEC contact because addition of isolated tumor cell membrane fragments but not of soluble cell culture supernatant to HUVEC induced the CD44 receptor loss. PKCα activity was strongly enhanced in conditioned HUVEC. Blocking PKC prevented the reduction in PMN binding, indicating that this protein is involved in PMN adhesion regulation. A novel tumor escape strategy is presented here. Cell contact-dependent adhesion of tumor cells to the vascular wall promotes down-regulation of endothelial CD44 receptor expression, impairing an effective neutrophil attack.

  7. Noninvasive molecular imaging of hypoxia in human xenografts: comparing hypoxia-induced gene expression with endogenous and exogenous hypoxia markers.

    Science.gov (United States)

    He, Fuqiu; Deng, Xuelong; Wen, Bixiu; Liu, Yueping; Sun, Xiaorong; Xing, Ligang; Minami, Akiko; Huang, Yunhong; Chen, Qing; Zanzonico, Pat B; Ling, C Clifton; Li, Gloria C

    2008-10-15

    Tumor hypoxia is important in the development and treatment of human cancers. We have developed a novel xenograft model for studying and imaging of hypoxia-induced gene expression. A hypoxia-inducible dual reporter herpes simplex virus type 1 thymidine kinase and enhanced green fluorescence protein (HSV1-TKeGFP), under the control of hypoxia response element (9HRE), was stably transfected into human colorectal HT29 cancer cells. Selected clones were further enriched by repeated live cell sorting gated for hypoxia-induced eGFP expression. Fluorescent microscopy, fluorescence-activated cell sorting, and radioactive substrate trapping assays showed strong hypoxia-induced expression of eGFP and HSV1-tk enzyme in the HT29-9HRE cells in vitro. Sequential micropositron emission tomography (PET) imaging of tumor-bearing animals, using the hypoxic cell tracer (18)F-FMISO and the reporter substrate (124)I-FIAU, yielded similar tumor hypoxia images for the HT29-9HRE xenograft but not in the parental HT29 tumor. Using autoradiography and IHC, detailed spatial distributions in tumor sections were obtained and compared for the following hypoxia-associated biomarkers in the HT29-9HRE xenograft: (124)I-FIAU, (18)F-FMISO, Hoechst (perfusion), lectin-TRITC (functional blood vessels), eGFP, pimonidazole, EF5, and CA9. Intratumoral distributions of (124)I-FIAU and (18)F-FMISO were similar, and eGFP, pimonidazole, EF5, and CA9 colocalized in the same areas but not in well-perfused regions that were positive for Hoechst and lectin-TRITC. In enabling the detection of hypoxia-induced molecular events and mapping their distribution in vivo with serial noninvasive positron emission tomography imaging, and multiple variable analysis with immunohistochemistry and fluorescence microscopy, this human xenograft model provides a valuable tool for studying tumor hypoxia and in validating existing and future exogenous markers for tumor hypoxia.

  8. Tumorer

    DEFF Research Database (Denmark)

    Prause, J.U.; Heegaard, S.

    2005-01-01

    oftalmologi, øjenlågstumorer, conjunctivale tumorer, malignt melanom, retinoblastom, orbitale tumorer......oftalmologi, øjenlågstumorer, conjunctivale tumorer, malignt melanom, retinoblastom, orbitale tumorer...

  9. An Oral DNA Vaccine Encoding Endoglin Eradicates Breast Tumors by Blocking Their Blood Supply

    Science.gov (United States)

    2007-05-01

    endothelial cells in the tumor vasculature, which effectively suppressed angiogenesis and thereby tumor growth and metastasis in several solid tumor mod- els ...Cancer Metastases 91 [24] R. Xiang, H.N. Lode, T.H. Chao, J.M. Ruehlmann, C.S. Dol- man, F. Rodriguez, J.L. Whitton, W.W. Overwijk, N.P. Res- tifo and R.A...Piek E, Roberts AB (2000) Role of trans- forming growth factor-beta signaling in cancer. J Natl Cancer Inst 92:1388–1402 Sp ot s/ 2 10 5 T c el ls 0

  10. Cerebral Hypoxia

    Science.gov (United States)

    ... off. When hypoxia lasts for longer periods of time, it can cause coma, seizures, and even brain death. In brain death, there is no measurable activity in the brain, although cardiovascular function is preserved. Life support is required for respiration. × Definition Cerebral hypoxia ...

  11. Oridonin inhibits tumor growth and metastasis through anti-angiogenesis by blocking the Notch signaling.

    Directory of Open Access Journals (Sweden)

    Yanmin Dong

    Full Text Available While significant progress has been made in understanding the anti-inflammatory and anti-proliferative effects of the natural diterpenoid component Oridonin on tumor cells, little is known about its effect on tumor angiogenesis or metastasis and on the underlying molecular mechanisms. In this study, Oridonin significantly suppressed human umbilical vascular endothelial cells (HUVECs proliferation, migration, and apillary-like structure formation in vitro. Using aortic ring assay and mouse corneal angiogenesis model, we found that Oridonin inhibited angiogenesis ex vivo and in vivo. In our animal experiments, Oridonin impeded tumor growth and metastasis. Immunohistochemistry analysis further revealed that the expression of CD31 and vWF protein in xenografts was remarkably decreased by the Oridonin. Furthermore, Oridonin reinforced endothelial cell-cell junction and impaired breast cancer cell transendothelial migration. Mechanistically, Oridonin not only down-regulated Jagged2 expression and Notch1 activity but also decreased the expression of their target genes. In conclusion, our results demonstrated an original role of Oridonin in inhibiting tumor angiogenesis and propose a mechanism. This study also provides new evidence supporting the central role of Notch in tumor angiogenesis and suggests that Oridonin could be a potential drug candidate for angiogenesis related diseases.

  12. Blocking Tumor Necrosis Factor α Enhances CD8 T-cell-Dependent Immunity in Experimental Melanoma.

    Science.gov (United States)

    Bertrand, Florie; Rochotte, Julia; Colacios, Céline; Montfort, Anne; Tilkin-Mariamé, Anne-Françoise; Touriol, Christian; Rochaix, Philippe; Lajoie-Mazenc, Isabelle; Andrieu-Abadie, Nathalie; Levade, Thierry; Benoist, Hervé; Ségui, Bruno

    2015-07-01

    TNF plays a dual, still enigmatic role in melanoma, either acting as a cytotoxic cytokine or favoring a tumorigenic inflammatory microenvironment. Herein, the tumor growth of melanoma cell lines expressing major histocompatibility complex class I molecules at high levels (MHC-I(high)) was dramatically impaired in TNF-deficient mice, and this was associated with enhanced tumor-infiltrating CD8(+) T lymphocytes. Immunodepletion of CD8 T cells fully restored melanoma growth in TNF(-/-) mice. Systemic administration of Etanercept inhibited MHC-I(high) melanoma growth in immunocompetent but not in immunodeficient (IFNγ(-/-), nude, or CD8(-/-)) mice. MHC-I(high) melanoma growth was also reduced in mice lacking TNF-R1, but not TNF-R2. TNF(-/-) and TNF-R1(-/-) mice as well as Etanercept-treated WT mice displayed enhanced intratumor content of high endothelial venules surrounded by high CD8(+) T-cell density. Adoptive transfer of activated TNF-R1-deficient or -proficient CD8(+) T cells in CD8-deficient mice bearing B16K1 tumors demonstrated that TNF-R1 deficiency facilitates the accumulation of live CD8(+) T cells into the tumors. Moreover, in vitro experiments indicated that TNF triggered activated CD8(+) T cell death in a TNF-R1-dependent manner, likely limiting the accumulation of tumor-infiltrating CD8(+) T cells in TNF/TNF-R1-proficient animals. Collectively, our observations indicate that TNF-R1-dependent TNF signaling impairs tumor-infiltrating CD8(+) T-cell accumulation and may serve as a putative target to favor CD8(+) T-cell-dependent immune response in melanoma. ©2015 American Association for Cancer Research.

  13. Diagnostic Value of Processing Cytologic Aspirates of Renal Tumors in Agar Cell (Tissue) Blocks

    DEFF Research Database (Denmark)

    Smedts, F.; Schrik, M.; Horn, T.

    2010-01-01

    Objective To adapt a method enabling utilization of most of the harvest from a fine needle aspirate in an effort to improve diagnostic accuracy in the assessment of a renal tumor in a single histologic slide. Study Design In a series of 43 renal tumors, 2 fine needle aspirations were performed, 4...... smears were prepared after each aspiration for conventional cytology and the remaining aspirate was processed for the improved agar microbiopsy (AM) method. Conventional cytology slides, AM slides and surgical specimens were diagnosed separately, after which the diagnoses were compared...

  14. Diagnostic Value of Processing Cytologic Aspirates of Renal Tumors in Agar Cell (Tissue) Blocks

    DEFF Research Database (Denmark)

    Smedts, F.; Schrik, M.; Horn, T.

    2010-01-01

    smears were prepared after each aspiration for conventional cytology and the remaining aspirate was processed for the improved agar microbiopsy (AM) method. Conventional cytology slides, AM slides and surgical specimens were diagnosed separately, after which the diagnoses were compared....... Immunohistochemistry was performed as required on the AM sections. Surgical specimens served as the gold standard. Results In 53% of conventional cytologic smears, the cellular yield was sufficient to render a correct diagnosis. In 12% the diagnosis was incorrect, in 21% only a differential diagnosis could be fin......-initiated, and in 14% too few diagnostic cells were present in the conventional smears for cytologic diagnosis. It was, however, possible to correctly diagnose histologic sections from 97% of AM tissue blocks. In 11 cases this was facilitated with immunochemistry. In only 1 case did the AM tissue block contain too few...

  15. First Evaluation of PET-Based Human Biodistribution and Dosimetry of 18F-FAZA, a Tracer for Imaging Tumor Hypoxia.

    Science.gov (United States)

    Savi, Annarita; Incerti, Elena; Fallanca, Federico; Bettinardi, Valentino; Rossetti, Francesca; Monterisi, Cristina; Compierchio, Antonia; Negri, Giampiero; Zannini, Piero; Gianolli, Luigi; Picchio, Maria

    2017-08-01

    18 F-labeled fluoroazomycinarabinoside ( 18 F-FAZA) is a PET biomarker for noninvasive identification of regional tumor hypoxia. The aim of the present phase I study was to evaluate the biodistribution and dosimetry of 18 F-FAZA in non-small cell lung cancer patients. Methods: Five patients awaiting surgical resection of histologically proven or radiologically suspected non-small cell lung cancer were prospectively enrolled in the study. The patients underwent PET/CT after injection of 371 ± 32 MBq of 18 F-FAZA. The protocol consisted of a 10-min dynamic acquisition of the heart to calculate the activity in blood, followed by 4 whole-body PET/CT scans, from the vertex to the mid thigh, at 10, 60, 120, and 240 min after injection. Urine samples were collected after each imaging session and at 360 min after injection. Volumes of interest were drawn around visually identifiable source organs to generate time-activity curves. Residence times were determined from time-activity curves, and effective doses to individual organs and the whole body were calculated using OLINDA/EXM 1.2 for the standard male and female phantoms. Results: Blood clearance was characterized by a rapid distribution followed by first-order elimination. The highest uptake was in muscle and liver, with respective percentage injected activity (%IA) peaks of 42.7 ± 5.3 %IA and 5.5 ± 0.6 %IA. The total urinary excretion was 15 %IA. The critical organ, with the highest absorbed radiation doses, was the urinary bladder wall, at 0.047 ± 0.008 and 0.067 ± 0.007 mGy/MBq for the 2- and 4-h voiding intervals, respectively. The effective doses for the standard male and female phantoms were 0.013 ± 0.004 and 0.014 ± 0.004 mSv/MBq, respectively, depending on the voiding schedule. Conclusion: With respect to the available literature, the biodistribution of 18 F-FAZA in humans appeared to be slightly different from that in mice, with a low clearance in humans. Therefore, use of animal data may moderately

  16. Hypoxia as a Biomarker and for Personalized Radiation Oncology

    DEFF Research Database (Denmark)

    Vordermark, Dirk; Horsman, Michael R

    2016-01-01

    Tumor hypoxia is a clinically relevant cause of radiation resistance. Direct measurements of tumor oxygenation have been performed predominantly with the Eppendorf histograph and these have defined the reduced prognosis after radiotherapy in poorly oxygenated tumors, especially head-and-neck cancer...... linked to poor prognosis after radiotherapy and such proteins are considered as potential endogenous hypoxia markers....

  17. Electron paramagnetic resonance imaging of tumor hypoxia: enhanced spatial and temporal resolution for in vivo pO2 determination.

    Science.gov (United States)

    Matsumoto, Ken-ichiro; Subramanian, Sankaran; Devasahayam, Nallathamby; Aravalluvan, Thirumaran; Murugesan, Ramachandran; Cook, John A; Mitchell, James B; Krishna, Murali C

    2006-05-01

    The time-domain (TD) mode of electron paramagnetic resonance (EPR) data collection offers a means of estimating the concentration of a paramagnetic probe and the oxygen-dependent linewidth (LW) to generate pO2 maps with minimal errors. A methodology for noninvasive pO2 imaging based on the application of TD-EPR using oxygen-induced LW broadening of a triarylmethyl (TAM)-based radical is presented. The decay of pixel intensities in an image is used to estimate T2*, which is inversely proportional to pO2. Factors affecting T2* in each pixel are critically analyzed to extract the contribution of dissolved oxygen to EPR line-broadening. Suitable experimental and image-processing parameters were obtained to produce pO2 maps with minimal artifacts. Image artifacts were also minimized with the use of a novel data collection strategy using multiple gradients. Results from a phantom and in vivo imaging of tumor-bearing mice validated this novel method of noninvasive oximetry. The current imaging protocols achieve a spatial resolution of approximately 1.0 mm and a temporal resolution of approximately 9 s for 2D pO2 mapping, with a reliable oxygen resolution of approximately 1 mmHg (0.12% oxygen in gas phase). This work demonstrates that in vivo oximetry can be performed with good sensitivity, accuracy, and high spatial and temporal resolution.

  18. Targeting vascular NADPH oxidase 1 blocks tumor angiogenesis through a PPARα mediated mechanism.

    Directory of Open Access Journals (Sweden)

    Sarah Garrido-Urbani

    Full Text Available Reactive oxygen species, ROS, are regulators of endothelial cell migration, proliferation and survival, events critically involved in angiogenesis. Different isoforms of ROS-generating NOX enzymes are expressed in the vasculature and provide distinct signaling cues through differential localization and activation. We show that mice deficient in NOX1, but not NOX2 or NOX4, have impaired angiogenesis. NOX1 expression and activity is increased in primary mouse and human endothelial cells upon angiogenic stimulation. NOX1 silencing decreases endothelial cell migration and tube-like structure formation, through the inhibition of PPARα, a regulator of NF-κB. Administration of a novel NOX-specific inhibitor reduced angiogenesis and tumor growth in vivo in a PPARα dependent manner. In conclusion, vascular NOX1 is a critical mediator of angiogenesis and an attractive target for anti-angiogenic therapies.

  19. Evaluation of uterine cervix cancer hypoxia by PET with {sup 18}F-F.E.T.N.I.M.. Relation with squamous cell carcinoma (S.C.C.) and osteopontin tumoral markers; Evaluation de l'hypoxie du cancer du col uterin par la TEP au {sup 18}F-FETNIM. Relation avec les marqueurs tumoraux SCC et osteopontine

    Energy Technology Data Exchange (ETDEWEB)

    Barre, E.; Schlageter, M.H.; Groheux, D.; Vercellino, L.; Lussato, D.; Thoury, A.; Hennequin, V.; Hindie, E.; Barranger, E.; Moretti, J.L. [CHU Saint-Louis-Lariboisiere, universite Paris-7, IMDCT, 75 - Paris (France)

    2010-07-01

    Purpose: to evaluate the imaging feasibility of hypoxia of cervical squamous cell carcinoma by PET with {sup 18}F-F.E.T.N.I.M. (Iason). to compare the {sup 18}F-F.E.T.N.I.M. uptake to the metabolic uptake in {sup 18}F-F.D.G. and to study their relationship with the squamous cell carcinoma, tumoral marker and osteoponin, circulating tracer of hypoxia. Conclusions: the F.E.T.N.I.M. uptake by the tumor is always of lower level than the {sup 18}F-F.D.G. uptake. By using the ratio Tumor/Muscle, these preliminary results do not enlighten any correlation between the circulating hypoxia tracer and the tumor uptake of {sup 18}F-F.E.T.N.I.M.. (N.C.)

  20. Golimumab and certolizumab: The two new anti-tumor necrosis factor kids on the block

    Directory of Open Access Journals (Sweden)

    Mittal Mohit

    2010-01-01

    Full Text Available Anti-tumor necrosis factor (anti-TNF agents have revolutionized treatment of psoriasis and many other inflammatory diseases of autoimmune origin. They have considerable advantages over the existing immunomodulators. Anti-TNF agents are designed to target a very specific component of the immune-mediated inflammatory cascades. Thus, they have lower risks of systemic side-effects. In a brief period of 10 years, a growing number of biological therapies are entering the clinical arena while many more biologicals remain on the horizon. With time, the long-term side-effects and efficacies of these individual agents will become clearer and help to determine which ones are the most suitable for long-term care. Golimumab (a human monoclonal anti-TNF-α antibody and Certolizumab (a PEGylated Fab fragment of humanized monoclonal TNF-α antibody are the two latest additions to the anti-TNF regimen. Here, we are providing a brief description about these two drugs and their uses.

  1. Assessment of regional tumor hypoxia using 18F-fluoromisonidazole and 64Cu(II)-diacetyl-bis(N4-methylthiosemicarbazone) positron emission tomography: Comparative study featuring microPET imaging, PO2 probe measurement, autoradiography, and fluorescent microscopy in the R3327-AT and FaDu rat tumor models

    International Nuclear Information System (INIS)

    O'Donoghue, Joseph A.; Zanzonico, Pat; Pugachev, Andrei; Wen Bixiu; Smith-Jones, Peter; Cai Shangde; Burnazi, Eva; Finn, Ronald D.; Burgman, Paul; Ruan, Shutian; Lewis, Jason S.; Welch, Michael J.; Ling, C. Clifton; Humm, John L.

    2005-01-01

    Purpose: To compare two potential positron emission tomography (PET) tracers of tumor hypoxia in an animal model. Methods and Materials: The purported hypoxia imaging agents 18 F-fluoromisonidazole (FMISO) and 64 Cu(II)-diacetyl-bis(N4-methylthiosemicarbazone) (Cu-ATSM) were compared by serial microPET imaging of Fisher-Copenhagen rats bearing the R3327-AT anaplastic rat prostate tumor. Probe measurements of intratumoral PO 2 were compared with the image data. At the microscopic level, the relationship between the spatial distributions of 64 Cu (assessed by digital autoradiography) and tumor hypoxia (assessed by immunofluorescent detection of pimonidazole) was examined. 18 F-FMISO and 64 Cu-ATSM microPET images were also acquired in nude rats bearing xenografts derived from the human squamous cell carcinoma cell line, FaDu. Results: In R3327-AT tumors, the intratumoral distribution of 18 F-FMISO remained relatively constant 1-4 h after injection. However, that of 64 Cu-ATSM displayed a significant temporal evolution for 0.5-20 h after injection in most tumors. In general, only when 64 Cu-ATSM was imaged at later times (16-20 h after injection) did it correspond to the distribution of 18 F-FMISO. Oxygen probe measurements were broadly consistent with 18 F-FMISO and late 64 Cu-ATSM images but not with early 64 Cu-ATSM images. At the microscopic level, a negative correlation was found between tumor hypoxia and 64 Cu distribution when assessed at early times and a positive correlation when assessed at later times. For the FaDu tumor model, the early and late 64 Cu-ATSM microPET images were similar and were in general concordance with the 18 F-FMISO scans. Conclusion: The difference in behavior between the R3327-AT and FaDu tumor models suggests a tumor-specific dependence of Cu-ATSM uptake and retention under hypoxic conditions

  2. Hypoxia and hypoxia-regulated proteins in gastric cancer: prognostic significance for clinical outcome

    International Nuclear Information System (INIS)

    Osinsky, S.; Gumenjuk, L.; Bubnovskaya, L.; Merentsev, S.; Kovelskaya, A.; Shalimov, S.; Osinsky, D.; Olijnichenko, G.

    2005-01-01

    Full text: To examine the relationship between hypoxia level, hypoxia-inducible factor-1α (HIF-1α) expression, tumor vascularity, and clinicopathologic parameters in gastric cancer; to assess the impact of hypoxia-associated events on the prognosis of clinical outcome. High hypoxia levels were found in 29 % of pts., and low - in 71 % of pts. Strong nuclear expressions of HIF-1α were found in 7 % of pts., moderate - in 80 % of pts., and weak - in 13 % of pts. Strong microvessel densities were observed in 54 % of pts. and moderate - in 46 % of pts. It was revealed a close association between the hypoxia level in tumor assessed by 31 P NMR spectroscopy and expression of HIF-1α in tumor cells (P 0.05). Hypoxia level and microvessel density in tumor tissue correlated with clinical stage (P<0.05). High hypoxia levels positively correlated with decreased overall survival (P=0.044). For overall survival, hypoxia level and HIF-1α expression (hazard ratio, 2.10; 95 % CI, 0.67-4.67; P=0.035 and 3.45; 0.89-3.01, 0.047, respectively) were independently predictive in multivariate analysis for lymph-node negative patients; and hypoxia level (hazard ratio, 4.50; 95 % CI, 0.42-2.57; P=0.027) for lymph-node positive patients. Statistical analysis has indicated that PME/Pi ratio in tumor tissue may be used as an parameter of hypoxia level as well as independent prognostic factor of clinical outcome in patients with gastric cancer. Methodological approaches are started now to be used in the analysis of head and neck tumors treated with hyperthermia combined with radiation/chemotherapy. (author)

  3. The single N-glycan deletion mutant of soluble ErbB3 protein attenuates heregulin β1-induced tumor progression by blocking of the HIF-1 and Nrf2 pathway

    Energy Technology Data Exchange (ETDEWEB)

    Takamiya, Rina, E-mail: rinataka0429@gmail.com; Takahashi, Motoko; Uehara, Yasuaki; Ariki, Shigeru; Hashimoto, Jiro; Hasegawa, Yoshihiro; Kuroki, Yoshio

    2014-11-21

    Highlights: • The sErbB3 N418Q mutant blocks heregulin β1 induced nuclear accumulation of HIF-1α. • The sErbB3 N418Q mutant attenuates cancer cell migration induced by heregulin β1. • The sErbB3 N418Q mutant blocks heregulin β1 induced nuclear accumulation of Nrf2. • The sErbB3 N418Q mutant may be a potential therapeutic application for tumor. - Abstract: It has been well documented that activation of the ErbB3–PI3K–Akt pathway is implicated in tumor survival and progression. We previously demonstrated that the single N-glycan deletion mutant of soluble ErbB3 protein (sErbB3 N418Q) attenuates heregulin β1-induced ErbB3 signaling. The active PI3K–Akt pathway augments the nuclear accumulation of hypoxia inducible factor (HIF)-1α, which activates the transcription of many target genes and drives cancer progression. In this study, we focused on the effects of sErbB3 N418Q mutant on nuclear accumulation of HIF-1α. Pretreatment with the sErbB3 N418Q mutant suppressed heregulin β1-induced HIF-1α activation in MCF7 cells. Similar results were also obtained in other breast cancer cell lines, T47D and BT474. Interestingly, these suppressive effects were not observed with the sErbB3 wild type. In addition, pretreatment with the sErbB3 N418Q mutant suppressed the cell migration of MCF7 cells induced by heregulin β1. Furthermore, incubation with heregulin β1 also induced the nuclear accumulation of Nrf2, and this effect was also reduced by the sErbB3 N418Q mutant, but not the sErbB3 wild type. These findings indicated that the sErbB3 N418Q mutant suppressed malignant formation of cancer cells by blocking of the HIF-1α and Nrf2 pathways.

  4. Hypoxia inducible factor-1α-dependent epithelial to mesenchymal transition under hypoxic conditions in prostate cancer cells.

    Science.gov (United States)

    Li, Mingchuan; Wang, Yong Xing; Luo, Yong; Zhao, Jiahui; Li, Qing; Zhang, Jiao; Jiang, Yongguang

    2016-07-01

    Prostate cancer is the most commonly diagnosed cancer in men and the second leading cause of cancer death. Hypoxia is an environmental stimulus that plays an important role in the development and cancer progression especially for solid tumors. The key regulator under hypoxic conditions is stabilized hypoxia-inducible factor (HIF)-1α. In the present study, immune-fluorescent staining, siRNAs, qRT-PC, immunoblotting, cell migration and invasion assays were carried out to test typical epithelial to mesenchymal transition under hypoxia and the key regulators of this process in PC3, a human prostate cancer cell line. Our data demonstrated that hypoxia induces diverse molecular, phenotypic and functional changes in prostate cancer cells that are consistent with EMT. We also showed that a cell signal factor such as HIF-1α, which might be stabilized under hypoxic environment, is involved in EMT and cancer cell invasive potency. The induced hypoxia could be blocked by HIF-1α gene silencing and reoxygenation of EMT in prostate cancer cells, hypoxia partially reversed accompanied by a process of mesenchymal-epithelial reverting transition (MErT). EMT might be induced by activation of HIF-1α-dependent cell signaling in hypoxic prostate cancer cells.

  5. Hypoxic hypoxia as a means of modifying radiosensibility

    International Nuclear Information System (INIS)

    Neumeister, K.; Niemiec, C.; Bolck, M.; Jahns, J.; Kamprad, F.; Arnold, P.; Johannsen, U.; Koch, F.; Mehlhorn, G.

    1977-01-01

    Following an overview of the various possibilities of creating hypoxia in mammals, the problem of reducing radioresistance of hypoxic tumor cells is treated. Furthermore, the results of irradiation experiments with mice, rats and pigs breathing hypoxic mixtures of O 2 and N 2 are given and discussed with a view to applying hypoxic hypoxia in the radiotherapy of human tumors. (author)

  6. GABARAPL1 is required for increased EGFR membrane expression during hypoxia

    NARCIS (Netherlands)

    Keulers, T.G.; Schaaf, M.B.; Peeters, H.J.; Savelkouls, K.G.; Vooijs, M.A.; Bussink, J.; Jutten, B.; Rouschop, K.M.

    2015-01-01

    BACKGROUND AND PURPOSE: The epidermal growth factor receptor (EGFR) is overexpressed, amplified or mutated in various human epithelial tumors and hypoxia is a common feature of solid tumors. Both EGFR and hypoxia are associated with therapy resistance and poor treatment outcome. To survive hypoxia,

  7. Saururus cernuus lignans-Potent small molecule inhibitors of hypoxia-inducible factor-1

    International Nuclear Information System (INIS)

    Hossain, Chowdhury Faiz; Kim, Yong-Pil; Baerson, Scott R.; Zhang Lei; Bruick, Richard K.; Mohammed, Kaleem A.; Agarwal, Ameeta K.; Nagle, Dale G.; Zhou Yudong

    2005-01-01

    Hypoxia-inducible factor-1 (HIF-1) represents an important tumor-selective therapeutic target for solid tumors. In search of novel small molecule HIF-1 inhibitors, 5400 natural product-rich extracts from plants, marine organisms, and microbes were examined for HIF-1 inhibitory activities using a cell-based reporter assay. Bioassay-guided fractionation and isolation, followed by structure elucidation, yielded three potent natural product-derived HIF-1 inhibitors and two structurally related inactive compounds. In a T47D cell-based reporter assay, manassantin B 1 , manassantin A, and 4-O-methylsaucerneol inhibited hypoxia-induced HIF-1 activation with IC 50 values of 3, 3, and 20 nM, respectively. All three compounds are relatively hypoxia-specific inhibitors of HIF-1 activation, in comparison to other stimuli. The hypoxic induction of HIF-1 target genes CDKN1A, VEGF, and GLUT-1 were also inhibited. These compounds inhibit HIF-1 by blocking hypoxia-induced nuclear HIF-1α protein accumulation without affecting HIF-1α mRNA levels. In addition, preliminary structure-activity studies suggest specific structural requirements for this class of HIF-1 inhibitors

  8. Hypobaric intermittent hypoxia attenuates hypoxia-induced depressor response.

    Directory of Open Access Journals (Sweden)

    Fang Cui

    Full Text Available Hypobaric intermittent hypoxia (HIH produces many favorable effects in the cardiovascular system such as anti-hypertensive effect. In this study, we showed that HIH significantly attenuated a depressor response induced by acute hypoxia.Sprague-Dawley rats received HIH in a hypobaric chamber simulating an altitude of 5000 m. The artery blood pressure (ABP, heart rate (HR and renal sympathetic nerve activity (RSNA were recorded in anesthetized control rats and rats received HIH. The baseline ABP, HR and RSNA were not different between HIH and control rats. Acute hypoxia-induced decrease in ABP was significantly attenuated in HIH rat compared with control rats. However, acute hypoxia-induced increases in HR and RSNA were greater in HIH rat than in control rats. After removal of bilateral ascending depressor nerves, acute hypoxia-induced depressor and sympathoexcitatory responses were comparable in control and HIH rats. Furthermore, acute hypoxia-induced depressor and sympathoexcitatory responses did not differ between control and HIH groups after blocking ATP-dependent K(+ channels by glibenclamide. The baroreflex function evaluated by intravenous injection of phenylephrine and sodium nitroprusside was markedly augmented in HIH rats compared with control rats. The pressor and sympathoexcitatory responses evoked by intravenous injection of cyanide potassium were also significantly greater in HIH rats than in control rats.Our findings suggest that HIH suppresses acute hypoxia-induced depressor response through enhancement of baroreflex and chemoreflex function, which involves activation of ATP-dependent K(+ channels. This study provides new information and underlying mechanism on the beneficiary effect of HIH on maintaining cardiovascular homeostasis.

  9. A Comparative Study of the Hypoxia PET Tracers [{sup 18}F]HX4, [{sup 18}F]FAZA, and [{sup 18}F]FMISO in a Preclinical Tumor Model

    Energy Technology Data Exchange (ETDEWEB)

    Peeters, Sarah G.J.A., E-mail: sarah.peeters@maastrichtuniversity.nl [Department of Radiation Oncology, GROW - School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht (Netherlands); Zegers, Catharina M.L.; Lieuwes, Natasja G.; Elmpt, Wouter van [Department of Radiation Oncology, GROW - School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht (Netherlands); Eriksson, Jonas; Dongen, Guus A.M.S. van [Department of Radiology and Nuclear Medicine, VU University Medical Center Amsterdam, Amsterdam (Netherlands); Dubois, Ludwig; Lambin, Philippe [Department of Radiation Oncology, GROW - School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht (Netherlands)

    2015-02-01

    Purpose: Several individual clinical and preclinical studies have shown the possibility of evaluating tumor hypoxia by using noninvasive positron emission tomography (PET). The current study compared 3 hypoxia PET tracers frequently used in the clinic, [{sup 18}F]FMISO, [{sup 18}F]FAZA, and [{sup 18}F]HX4, in a preclinical tumor model. Tracer uptake was evaluated for the optimal time point for imaging, tumor-to-blood ratios (TBR), spatial reproducibility, and sensitivity to oxygen modification. Methods and Materials: PET/computed tomography (CT) images of rhabdomyosarcoma R1-bearing WAG/Rij rats were acquired at multiple time points post injection (p.i.) with one of the hypoxia tracers. TBR values were calculated, and reproducibility was investigated by voxel-to-voxel analysis, represented as correlation coefficients (R) or Dice similarity coefficient of the high-uptake volume. Tumor oxygen modifications were induced by exposure to either carbogen/nicotinamide treatment or 7% oxygen breathing. Results: TBR was stabilized and maximal at 2 hours p.i. for [{sup 18}F]FAZA (4.0 ± 0.5) and at 3 hours p.i. for [{sup 18}F]HX4 (7.2 ± 0.7), whereas [{sup 18}F]FMISO showed a constant increasing TBR (9.0 ± 0.8 at 6 hours p.i.). High spatial reproducibility was observed by voxel-to-voxel comparisons and Dice similarity coefficient calculations on the 30% highest uptake volume for both [{sup 18}F]FMISO (R = 0.86; Dice coefficient = 0.76) and [{sup 18}F]HX4 (R = 0.76; Dice coefficient = 0.70), whereas [{sup 18}F]FAZA was less reproducible (R = 0.52; Dice coefficient = 0.49). Modifying the hypoxic fraction resulted in enhanced mean standardized uptake values for both [{sup 18}F]HX4 and [{sup 18}F]FAZA upon 7% oxygen breathing. Only [{sup 18}F]FMISO uptake was found to be reversible upon exposure to nicotinamide and carbogen. Conclusions: This study indicates that each tracer has its own strengths and, depending on the question to be answered, a different tracer can be put

  10. [18F]Fluoro-azomycin-2´-deoxy-β-D-ribofuranoside — A new imaging agent for tumor hypoxia in comparison with [18F]FAZA

    International Nuclear Information System (INIS)

    Schweifer, Anna; Maier, Florian; Ehrlichmann, Walter; Lamparter, Denis; Kneilling, Manfred; Pichler, Bernd J.; Hammerschmidt, Friedrich; Reischl, Gerald

    2016-01-01

    Introduction: Radiolabeled 2-nitroimidazoles (azomycins) are a prominent class of biomarkers for PET imaging of hypoxia. [ 18 F]Fluoro-azomycin-α-arabinoside ([ 18 F]FAZA) – already in clinical use – may be seen as α-configuration nucleoside, but enters cells only via diffusion and is not transported by cellular nucleoside transporters. To enhance image contrast in comparison to [ 18 F]FAZA our objective was to 18 F-radiolabel an azomycin-2´-deoxyriboside with β-configuration ([ 18 F]FAZDR, [ 18 F]-β-8) to mimic nucleosides more closely and comparatively evaluate it versus [ 18 F]FAZA. Methods: Precursor and cold standards for [ 18 F]FAZDR were synthesized from methyl 2-deoxy-D-ribofuranosides α- and β-1 in 6 steps yielding precursors α- and β-5. β-5 was radiolabeled in a GE TRACERlab FX F-N synthesizer in DMSO and deprotected with NH 4 OH to give [ 18 F]FAZDR ([ 18 F]-β-8). [ 18 F]FAZA or [ 18 F]FAZDR was injected in BALB/c mice bearing CT26 colon carcinoma xenografts, PET scans (10 min) were performed after 1, 2 and 3 h post injection (p.i.). On a subset of mice injected with [ 18 F]FAZDR, we analyzed biodistribution. Results: [ 18 F]FAZDR was obtained in non-corrected yields of 10.9 ± 2.4% (9.1 ± 2.2 GBq, n = 4) 60 min EOB, with radiochemical purity >98% and specific activity >50 GBq/μmol. Small animal PET imaging showed a decrease in uptake over time for both [ 18 F]FAZDR (1 h p.i.: 0.56 ± 0.22% ID/cc, 3 h: 0.17 ± 0.08% ID/cc, n = 9) and [ 18 F]FAZA (1 h: 1.95 ± 0.59% ID/cc, 3 h: 0.87 ± 0.55% ID/cc), whereas T/M ratios were significantly higher for [ 18 F]FAZDR at 1 h (2.76) compared to [ 18 F]FAZA (1.69, P < 0.001), 3 h p.i. ratios showed no significant difference. Moreover, [ 18 F]FAZDR showed an inverse correlation between tracer uptake in carcinomas and oxygen breathing, while muscle tissue uptake was not affected by switching from air to oxygen. Conclusions: First PET imaging results with [ 18 F]FAZDR showed advantages over [ 18 F

  11. [Birth hypoxia].

    Science.gov (United States)

    Větr, M

    2015-03-01

    Evaluation of the commonly used laboratory and clinical parameters of the newborn shortly after birth. Check thresholds acidemia, and in relation to the method of termination of pregnancy. Retrospective epidemiological study. Department of Obstetrics and Gynecology, University Hospital, Olomouc. Of the 26,869 children born in the years 2000 to 2013 Inclusion criteria (complete clinical and laboratory findings after birth) fulfill 23,471 (87.4%) neonates. Methods for evaluation of newborns included Apgar score calculation and arterial umbilical cord blood pH and lactate analysis. A total of 0.7% (157) of the neonates had severe acidosis pH below 7.00 arterial umbilical cord blood, its prevalence varies annually between 0.1 to 1.1%. Cutoff lactate in relation to pH reserves. Operating cesarean births in particular accounts for more than half of those with worse clinical findings Apgar and pH <7.00, but only 30% supratreshold lactate values. Also worse clinical evaluation after caesarean section is not in accordance with the laboratory findings. Vaginal surgery, especially forceps have a significant share of severe acidosis than cesarean, regardless of their frequency. Risk factor of forceps to pH less 7.00,OR = 9.28 (5.39 -15.77), P = 0.0000000, while caesarean to pH less 7,00 had OR = 1.52 (1.08 to 2.14), P = 0.01408156. The results obtained confirm that acidosis after birth is quite common, although they may not have response on the clinical condition of the newborn after birth. Evaluation of Apgar is little objective for the detection of hypoxia during birth and is influenced by the immaturity of newborn and method of delivery. Lactate levels may contribute to an objective assessment of hypoxia during birth. Values above 6.3 mmol/l can be considered an important indicator of newborn acidosis and birth hypoxia.

  12. Kinetic modeling in PET imaging of hypoxia

    DEFF Research Database (Denmark)

    Li, Fan; Jørgensen, Jesper Tranekjær; Hansen, Anders E

    2014-01-01

    Tumor hypoxia is associated with increased therapeutic resistance leading to poor treatment outcome. Therefore the ability to detect and quantify intratumoral oxygenation could play an important role in future individual personalized treatment strategies. Positron Emission Tomography (PET) can...... be used for non-invasive mapping of tissue oxygenation in vivo and several hypoxia specific PET tracers have been developed. Evaluation of PET data in the clinic is commonly based on visual assessment together with semiquantitative measurements e.g. standard uptake value (SUV). However, dynamic PET...... analysis for PET imaging of hypoxia....

  13. Folic Acid Represses Hypoxia-Induced Inflammation in THP-1 Cells through Inhibition of the PI3K/Akt/HIF-1α Pathway.

    Directory of Open Access Journals (Sweden)

    Xiaoyan Huang

    Full Text Available Though hypoxia has been implicated as a cause of inflammation, the underlying mechanism is not well understood. Folic acid has been shown to provide protection against oxidative stress and inflammation in patients with cardiovascular disease and various models approximating insult to tissue via inflammation. It has been reported that hypoxia-induced inflammation is associated with oxidative stress, upregulation of hypoxia-inducible factor 1-alpha (HIF-1α, and production of pro-inflammatory molecules. Whether folic acid protects human monocytic cells (THP-1 cells against hypoxia-induced damage, however, remains unknown. We used THP-1 cells to establish a hypoxia-induced cellular injury model. Pretreating THP-1 cells with folic acid attenuated hypoxia-induced inflammatory responses, including a decrease in protein and mRNA levels of interleukin (IL-1β and tumor necrosis factor-alpha (TNF-α, coupled with increased levels of IL-10. Folic acid also reduced hypoxia-induced Akt phosphorylation and decreased nuclear accumulation of HIF-1α protein. Both LY294002 (a selective inhibitor of phosphatidyl inositol-3 kinase, PI3K and KC7F2 (a HIF-1α inhibitor reduced levels of hypoxia-induced inflammatory cytokines. We also found that insulin (an Akt activator and dimethyloxallyl glycine (DMOG, a HIF-1α activator induced over-expression of inflammatory cytokines, which could be blocked by folic acid. Taken together, these findings demonstrate how folic acid attenuates the hypoxia-induced inflammatory responses of THP-1 cells through inhibition of the PI3K/Akt/HIF-1α pathway.

  14. Nanotetrac targets integrin αvβ3 on tumor cells to disorder cell defense pathways and block angiogenesis

    Directory of Open Access Journals (Sweden)

    Davis PJ

    2014-09-01

    Full Text Available Paul J Davis,1,2 Hung-Yun Lin,2,3 Thangirala Sudha,2 Murat Yalcin,2,4 Heng-Yuan Tang,2 Aleck Hercbergs,5 John T Leith,6 Mary K Luidens,1 Osnat Ashur-Fabian,7,8 Sandra Incerpi,9 Shaker A Mousa2 1Department of Medicine, Albany Medical College, Albany, NY, USA; 2Pharmaceutical Research Institute, Albany College of Pharmacy and Health Sciences, Albany, NY, USA; 3PhD Program for Cancer Biology and Drug Discovery, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan; 4Department of Physiology, Veterinary Medicine Faculty, Uludag University, Gorukle, Bursa, Turkey; 5Radiation Oncology, Cleveland Clinic, Cleveland, OH, USA; 6Rhode Island Nuclear Science Center, Narragansett, RI, USA; 7Translational Hemato-oncology Laboratory, Hematology Institute and Blood Bank, Meir Medical Center, Kfar-Saba, Israel; 8Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; 9Department of Sciences, University of Roma Tre, Rome, Italy Abstract: The extracellular domain of integrin αvβ3 contains a receptor for thyroid hormone and hormone analogs. The integrin is amply expressed by tumor cells and dividing blood vessel cells. The proangiogenic properties of thyroid hormone and the capacity of the hormone to promote cancer cell proliferation are functions regulated nongenomically by the hormone receptor on αvβ3. An L-thyroxine (T4 analog, tetraiodothyroacetic acid (tetrac, blocks binding of T4 and 3,5,3'-triiodo-L-thyronine (T3 by αvβ3 and inhibits angiogenic activity of thyroid hormone. Covalently bound to a 200 nm nanoparticle that limits its activity to the cell exterior, tetrac reformulated as Nanotetrac has additional effects mediated by αvβ3 beyond the inhibition of binding of T4 and T3 to the integrin. These actions of Nanotetrac include disruption of transcription of cell survival pathway genes, promotion of apoptosis by multiple mechanisms, and interruption

  15. Hypoxia-inducible factor-1α mediates the toll-like receptor 4 signaling pathway leading to anti-tumor effects in human hepatocellular carcinoma cells under hypoxic conditions.

    Science.gov (United States)

    Zhang, Xiaoyu; Li, Shuchen; Li, Mingrong; Huang, Haiying; Li, Jingyuan; Zhou, Changwei

    2016-08-01

    Hypoxia-inducible factor-1α (HIF-1α) and toll-like receptor 4 (TLR4) are involved in numerous mechanisms of cancer biology, including cell proliferation and survival; however the interaction of the two factors under hypoxic conditions remains unclear. The present study investigated the in vitro mechanism that results in the suppression of tumor cell growth and cellular functions when HIF-1α is silenced. In the present study, the human hepatocellular carcinoma HepG2 cell line was transfected with short hairpin RNA (shRNA) against HIF-1α and cultured under hypoxic conditions (1% O 2 for 24 h). The expression of HIF-1α and various growth factors, including epidermal growth factor (EGF), hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF) and fibroblast growth factor 2 (FGF2), were examined using quantitative polymerase chain reaction and immunoblotting. Tumor growth was measured using a Cell Counting Kit-8 assay and tumor activity was measured using tumor cell invasion and migration assays. Lipopolysaccharide and TAK-242 were used to activate and inhibit TLR4, respectively, to observe the role of TLR4 in the HIF-1α silenced tumor cells. The expression of TLR4 signaling pathway associates, including myeloid differentiation primary response gene 88 (MyD88), apoptosis signal-regulating kinase 1 (ASK1), p38 mitogen-activated protein kinases and HIF-1α, were analyzed by western blot assay. Under hypoxic conditions, silencing of HIF-1α expression suppressed tumor cell growth and regulated the expression of tumor growth-associated genes, including EGF, HGF, VEGF and FG2. Suppression of tumor cell invasion and migration was also observed in the HIF-1α silenced HepG2 cell line. In addition, TLR4 was identified to be involved in HIF-1α and MyD88 accumulation, and activation of ASK1 and p38 were demonstrated to be critical for TLR4-mediated HIF-1α pathway. In conclusion, silencing of HIF-1α expression may induce anti-tumor effects under hypoxic

  16. A rationally designed combined treatment with an alphavirus-based cancer vaccine, sunitinib and low-dose tumor irradiation completely blocks tumor development

    NARCIS (Netherlands)

    Draghiciu, Oana; Boerma, Annemarie; Hoogeboom, Baukje Nynke; Nijman, Hans W.; Daemen, Toos

    2015-01-01

    The clinical efficacy of therapeutic cancer vaccines remains limited. For effective immunotherapeutic responses in cancer patients, multimodal approaches capable of both inducing antitumor immune responses and bypassing tumor-mediated immune escape seem essential. Here, we report on a combination

  17. MiR-142 modulates human pancreatic cancer proliferation and invasion by targeting hypoxia-inducible factor 1 (HIF-1α in the tumor microenvironments

    Directory of Open Access Journals (Sweden)

    Yebin Lu

    2017-02-01

    Full Text Available MicroRNAs regulate most protein-coding genes, including genes important in cancer and other diseases. In this study, we demonstrated that the expression of miR-142 could be significantly suppressed in pancreatic cancer specimens and cell lines compared to their adjacent tissues and normal pancreatic cells. Growth and invasion of PANC-1 and SW1990 cells were attenuated by overexpression of miR-142 in vitro. With the help of bioinformatics analysis, hypoxia-inducible factor 1 (HIF-1α was identified to be a direct target of miR-142, and a luciferase reporter experiment confirmed this discovery. Overexpression of miR-142 decreases protein expression of HIF-1α. In the hypoxic microenvironment, HIF-1α was up-regulated while miR-142 was down-regulated. The invaded cells significantly increased in the hypoxic microenvironment compared to the normoxic microenvironment. The hypoxia treatment induced cells’ proliferation, and invasion could be inhibited by miR-142 overexpression or HIF-1α inhibition. Moreover, expression of epithelial-mesenchymal transition (EMT markers, Vimentin, VEGF-C and E-cad, was altered under hypoxia conditions and regulated by miR-142/HIF-1α. Above all, these findings provided insights on the functional mechanism of miR-142, suggesting that the miR-142/HIF-1α axis may interfere with the proliferative and invasive properties of pancreatic cancer cells, and indicated that miR-142 could be a potential therapeutic target for pancreatic cancer.

  18. Tumor-promoting phorbol ester transiently down-modulates the p53 level and blocks the cell cycle

    DEFF Research Database (Denmark)

    Skouv, J.; Jensen, P O; Forchhammer, J

    1994-01-01

    Activation of the protein kinase C signaling pathway by tumor-promoting phorbol esters, such as 4 beta-phorbol 12-myristate 13-acetate (PMA), induced a decrease in the level of p53 mRNA in several serum-starved human cell lines. Also, the tumor-promoting phosphatase inhibitor okadaic acid induced...

  19. mTOR inhibitors block Kaposi sarcoma growth by inhibiting essential autocrine growth factors and tumor angiogenesis.

    Science.gov (United States)

    Roy, Debasmita; Sin, Sang-Hoon; Lucas, Amy; Venkataramanan, Raman; Wang, Ling; Eason, Anthony; Chavakula, Veenadhari; Hilton, Isaac B; Tamburro, Kristen M; Damania, Blossom; Dittmer, Dirk P

    2013-04-01

    Kaposi sarcoma originates from endothelial cells and it is one of the most overt angiogenic tumors. In Sub-Saharan Africa, where HIV and the Kaposi sarcoma-associated herpesvirus (KSHV) are endemic, Kaposi sarcoma is the most common cancer overall, but model systems for disease study are insufficient. Here, we report the development of a novel mouse model of Kaposi sarcoma, where KSHV is retained stably and tumors are elicited rapidly. Tumor growth was sensitive to specific allosteric inhibitors (rapamycin, CCI-779, and RAD001) of the pivotal cell growth regulator mTOR. Inhibition of tumor growth was durable up to 130 days and reversible. mTOR blockade reduced VEGF secretion and formation of tumor vasculature. Together, the results show that mTOR inhibitors exert a direct anti-Kaposi sarcoma effect by inhibiting angiogenesis and paracrine effectors, suggesting their application as a new treatment modality for Kaposi sarcoma and other cancers of endothelial origin. ©2012 AACR.

  20. Single-chain antibody-based gene therapy: Inhibition of tumor growth by in situ production of phage-derived antibodies blocking functionally active sites of cell-associated matrices

    DEFF Research Database (Denmark)

    Sanz, Laura; Kristensen, Peter; Blanco, Belén

    2002-01-01

    Experimental evidence suggests that blocking the interactions between endothelial cells and extracellular matrix (ECM) components may provide a potent and general strategy to inhibit tumor neovascularization. Based on these considerations, we have focused our efforts on laminin, component of the ...

  1. Hypoxia in head and neck cancer: How much, how important?

    NARCIS (Netherlands)

    Janssen, H. L.; Haustermans, K. M.; Balm, A. J.; Begg, A. C.

    2005-01-01

    BACKGROUND: Hypoxia develops in tumors because of a less ordered, often chaotic, and leaky vascular supply compared with that in normal tissues. In preclinical models, hypoxia has been shown to be associated with treatment resistance and increased malignant potential. In the clinic, several reports

  2. Intermittent hypoxia selects for genotypes and phenotypes that increase survival, invasion, and therapy resistance.

    Directory of Open Access Journals (Sweden)

    Daniel Verduzco

    Full Text Available Hypoxia in tumors correlates with greater risk of metastases, increased invasiveness, and resistance to systemic and radiation therapy. The evolutionary dynamics that links specific adaptations to hypoxia with these observed tumor properties have not been well investigated. While some tumor populations may experience fixed hypoxia, cyclical and stochastic transitions from normoxia to hypoxia are commonly observed in vivo. Although some phenotypic adaptations to this cyclic hypoxia are likely reversible, we hypothesize that some adaptations may become fixed through mutations promoted by hypoxia-induced genomic instability. Here we seek to identify genetic alterations and corresponding stable phenotypes that emerge following cyclic hypoxia. Although these changes may originate as adaptations to this specific environmental stress, their fixation in the tumor genome may result in their observation in tumors from regions of normoxia, a condition known as pseudohypoxia. We exposed several epithelial cell lines to 50 cycles of hypoxia-normoxia, followed by culture in normoxia over a period of several months. Molecular analyses demonstrated permanent changes in expression of several oncogenes and tumor-suppressors, including p53, E-cadherin, and Hif-1α. These changes were associated with increased resistance to multiple cytotoxins, increased survival in hypoxia and increased anchorage-independent growth. These results suggest cycles of hypoxia encountered in early cancers can select for specific and stable genotypic and phenotypic properties that persist even in normoxic conditions, which may promote tumor progression and resistance to therapy.

  3. The Proteasome Inhibitor MG-132 Protects Hypoxic SiHa Cervical Carcinoma Cells after Cyclic Hypoxia/Reoxygenation from Ionizing Radiation

    Directory of Open Access Journals (Sweden)

    Frank Pajonk

    2006-12-01

    Full Text Available INTRODUCTION: Transient hypoxia and subsequent reoxygenation are common phenomena in solid tumors that greatly influence the outcome of radiation therapy. This study was designed to determine how varying cycles of hypoxia/reoxygenation affect the response of cervical carcinoma cells irradiated under oxic and hypoxic conditions and whether this could be modulated by proteasome inhibition. MATERIALS AND METHODS: Plateau-phase SiHa cervical carcinoma cells in culture were exposed to varying numbers of 30-minute cycles of hypoxia/reoxygenation directly before irradiation under oxic or hypoxic conditions. 26S Proteasome activity was blocked by addition of MG-132. Clonogenic survival was measured by a colonyforming assay. RESULTS: Under oxic conditions, repeated cycles of hypoxia/reoxygenation decreased the clonogenic survival of SiHa cells. This effect was even more pronounced after the inhibition of 26S proteasome complex. In contrast, under hypoxic conditions, SiHa cells were radioresistant, as expected, but this was increased by proteasome inhibition. CONCLUSIONS: Proteasome inhibition radiosensitizes oxygenated tumor cells but may also protect tumor cells from ionizing radiation under certain hypoxic conditions.

  4. The hypoxia-related microRNA miR-199a-3p displays tumor suppressor functions in ovarian carcinoma.

    Science.gov (United States)

    Kinose, Yasuto; Sawada, Kenjiro; Nakamura, Koji; Sawada, Ikuko; Toda, Aska; Nakatsuka, Erika; Hashimoto, Kae; Mabuchi, Seiji; Takahashi, Kazuhiro; Kurachi, Hirohisa; Lengyel, Ernst; Kimura, Tadashi

    2015-05-10

    During the dissemination of ovarian cancer cells, the cells float in the peritoneal cavity without access to a vascular supply and so are exposed to hypoxic conditions, which may cause the ovarian cancer cells to acquire a more aggressive and malignant phenotype. In this study, we screened microRNAs (miRNAs) to identify those that displayed altered expression patterns under hypoxic conditions and then analyzed their functional roles in ovarian cancer progression. miRNA PCR arrays performed on cells from 2 ovarian cancer cell lines (CaOV3 and RMUG-S) revealed miR-199a-3p as one of the miRNAs that are downregulated under hypoxia. In silico analyses indicated that MET is one of the target genes for miR-199a-3p; subsequently, miR-199a-3p expression was found to be inversely correlated with c-Met expression in ovarian cancer. Transfection of precursor miR-199a-3p into ovarian cancer cells reduced c-Met expression and inhibited the phosphorylation of c-Met, extracellular signal-regulated kinase, and AKT; in addition, proliferation, adhesion, and invasiveness were inhibited. Moreover, overexpression of miR-199a-3p in cancer cells significantly suppressed peritoneal dissemination in a xenograft model. In summary, the hypoxia-related microRNA miR-199a-3p drastically inhibits ovarian cancer progression through the downregulation of c-Met expression. Therefore, miR-199a-3p is a potential target for treating ovarian cancer dissemination.

  5. Mitochondrial respiratory function induces endogenous hypoxia.

    Science.gov (United States)

    Prior, Sara; Kim, Ara; Yoshihara, Toshitada; Tobita, Seiji; Takeuchi, Toshiyuki; Higuchi, Masahiro

    2014-01-01

    Hypoxia influences many key biological functions. In cancer, it is generally believed that hypoxic condition is generated deep inside the tumor because of the lack of oxygen supply. However, consumption of oxygen by cancer should be one of the key means of regulating oxygen concentration to induce hypoxia but has not been well studied. Here, we provide direct evidence of the mitochondrial role in the induction of intracellular hypoxia. We used Acetylacetonatobis [2-(2'-benzothienyl) pyridinato-kN, kC3'] iridium (III) (BTP), a novel oxygen sensor, to detect intracellular hypoxia in living cells via microscopy. The well-differentiated cancer cell lines, LNCaP and MCF-7, showed intracellular hypoxia without exogenous hypoxia in an open environment. This may be caused by high oxygen consumption, low oxygen diffusion in water, and low oxygen incorporation to the cells. In contrast, the poorly-differentiated cancer cell lines: PC-3 and MDAMB231 exhibited intracellular normoxia by low oxygen consumption. The specific complex I inhibitor, rotenone, and the reduction of mitochondrial DNA (mtDNA) content reduced intracellular hypoxia, indicating that intracellular oxygen concentration is regulated by the consumption of oxygen by mitochondria. HIF-1α was activated in endogenously hypoxic LNCaP and the activation was dependent on mitochondrial respiratory function. Intracellular hypoxic status is regulated by glucose by parabolic dose response. The low concentration of glucose (0.045 mg/ml) induced strongest intracellular hypoxia possibly because of the Crabtree effect. Addition of FCS to the media induced intracellular hypoxia in LNCaP, and this effect was partially mimicked by an androgen analog, R1881, and inhibited by the anti-androgen, flutamide. These results indicate that mitochondrial respiratory function determines intracellular hypoxic status and may regulate oxygen-dependent biological functions.

  6. Mitochondrial respiratory function induces endogenous hypoxia.

    Directory of Open Access Journals (Sweden)

    Sara Prior

    Full Text Available Hypoxia influences many key biological functions. In cancer, it is generally believed that hypoxic condition is generated deep inside the tumor because of the lack of oxygen supply. However, consumption of oxygen by cancer should be one of the key means of regulating oxygen concentration to induce hypoxia but has not been well studied. Here, we provide direct evidence of the mitochondrial role in the induction of intracellular hypoxia. We used Acetylacetonatobis [2-(2'-benzothienyl pyridinato-kN, kC3'] iridium (III (BTP, a novel oxygen sensor, to detect intracellular hypoxia in living cells via microscopy. The well-differentiated cancer cell lines, LNCaP and MCF-7, showed intracellular hypoxia without exogenous hypoxia in an open environment. This may be caused by high oxygen consumption, low oxygen diffusion in water, and low oxygen incorporation to the cells. In contrast, the poorly-differentiated cancer cell lines: PC-3 and MDAMB231 exhibited intracellular normoxia by low oxygen consumption. The specific complex I inhibitor, rotenone, and the reduction of mitochondrial DNA (mtDNA content reduced intracellular hypoxia, indicating that intracellular oxygen concentration is regulated by the consumption of oxygen by mitochondria. HIF-1α was activated in endogenously hypoxic LNCaP and the activation was dependent on mitochondrial respiratory function. Intracellular hypoxic status is regulated by glucose by parabolic dose response. The low concentration of glucose (0.045 mg/ml induced strongest intracellular hypoxia possibly because of the Crabtree effect. Addition of FCS to the media induced intracellular hypoxia in LNCaP, and this effect was partially mimicked by an androgen analog, R1881, and inhibited by the anti-androgen, flutamide. These results indicate that mitochondrial respiratory function determines intracellular hypoxic status and may regulate oxygen-dependent biological functions.

  7. Regulation of mRNA translation influences hypoxia tolerance

    International Nuclear Information System (INIS)

    Koritzinsky, M.; Wouters, B.G.; Koumenis, C.

    2003-01-01

    Hypoxia is a heterogenous but common characteristic of human tumours and poor oxygenation is associated with poor prognosis. We believe that the presence of viable hypoxic tumor cells reflects in part an adaptation and tolerance of these cells to oxygen deficiency. Since oxidative phosphorylation is compromized during hypoxia, adaptation may involve both the upregulation of glycolysis as well as downregulation of energy consumption. mRNA translation is one of the most energy costly cellular processes, and we and others have shown that global mRNA translation is rapidly inhibited during hypoxia. However, some mRNAs, including those coding for HIF-1 α and VEGF, remain efficiently translated during hypoxia. Clearly, the mechanisms responsible for the overall inhibition of translation during hypoxia does not compromize the translation of certain hypoxia-induced mRNA species. We therefore hypothesize that the inhibition of mRNA translation serves to promote hypoxia tolerance in two ways: i) through conservation of energy and ii) through differential gene expression involved in hypoxia adaptation. We have recently identified two pathways that are responsible for the global inhibition of translation during hypoxia. The phosphorylation of the eukaryotic initiation factor eIF2 α by the ER resident kinase PERK results in down-regulation of protein synthesis shortly after the onset of hypoxia. In addition, the initiation complex eIF4F is disrupted during long lasting hypoxic conditions. The identification of the molecular pathways responsible for the inhibition of overall translation during hypoxia has rendered it possible to investigate their importance for hypoxia tolerance. We have found that mouse embryo fibroblasts that are knockout for PERK and therefore not able to inhibit protein synthesis efficiently during oxygen deficiency are significantly less tolerant to hypoxia than their wildtype counterparts. We are currently also investigating the functional significance

  8. Hypoxia-induced tumor cell resistance is overcome by synergistic GAPDH-siRNA and chemotherapy co-delivered by long-circulating and cationic-interior liposomes

    NARCIS (Netherlands)

    Guan, J.; Sun, J.; Sun, F.|info:eu-repo/dai/nl/370549775; Lou, B.|info:eu-repo/dai/nl/37052537X; Zhang, D.; Mashayekhi, V.|info:eu-repo/dai/nl/413278360; Sadeghi, N.; Storm, G.|info:eu-repo/dai/nl/073356328; Mastrobattista, E.|info:eu-repo/dai/nl/228061105; He, Z.

    2017-01-01

    Chemotherapeutic drug resistance of tumor cells under hypoxic conditions is caused by the inhibition of apoptosis by autophagy and drug efflux via adenosine triphosphate (ATP)-dependent transporter activation, among other factors. Here, we demonstrate that disrupting glyceraldehyde-3-phosphate

  9. Migraine induced by hypoxia

    DEFF Research Database (Denmark)

    Arngrim, Nanna; Schytz, Henrik Winther; Britze, Josefine

    2016-01-01

    response to hypoxia. In a randomized double-blind crossover study design, 15 migraine with aura patients were exposed to 180 min of normobaric hypoxia (capillary oxygen saturation 70-75%) or sham on two separate days and 14 healthy controls were exposed to hypoxia. Glutamate and lactate concentrations...

  10. Blockade of Notch Signaling in Tumor-Bearing Mice May Lead to Tumor Regression, Progression, or Metastasis, Depending on Tumor Cell Types

    Directory of Open Access Journals (Sweden)

    Xing-Bin Hu

    2009-01-01

    Full Text Available It has been reported that blocking Notch signaling in tumor-bearing mice results in abortive angiogenesis and tumor regression. However, given that Notch signaling influences numerous cellular processes in vivo, a comprehensive evaluation of the effect of Notch inactivation on tumor growth would be favorable. In this study, we inoculated four cancer cell lines in mice with the conditional inactivation of recombination signal-binding protein-Jκ (RBP-J, which mediates signaling from all four mammalian Notch receptors. We found that whereas three tumors including hepatocarcinoma, lung cancer, and osteogenic sarcoma grew slower in the RBP-J-deficient mice, at least a melanoma, B16, grew significantly faster in the RBP-J-deficient mice than in the controls, suggesting that the RBP-J-deficient hosts could provide permissive cues for tumor growth. All these tumors showed increased microvessels and up-regulated hypoxia-inducible factor 1α, suggesting that whereas defective angiogenesis resulted in hypoxia, different tumors might grow differentially in the RBP-J-deleted mice. Similarly, increased infiltration of Gr1+/Mac1+ cells were noticed in tumors grown in the RBP-J-inactivated mice. Moreover, we found that when inoculated in the RBP-J knockout hosts, the H22 hepatoma cells had a high frequency of metastasis and lethality, suggesting that at least for H22, deficiency of environmental Notch signaling favored tumor metastasis. Our findings suggested that the general blockade of Notch signaling in tumor-bearing mice could lead to defective angiogenesis in tumors, but depending on tumor cell types, general inhibition of Notch signaling might result in tumor regression, progression, or metastasis.

  11. Hypoxia. 3. Hypoxia and neurotransmitter synthesis.

    Science.gov (United States)

    Kumar, Ganesh K

    2011-04-01

    Central and peripheral neurons as well as neuroendocrine cells express a variety of neurotransmitters/modulators that play critical roles in regulation of physiological systems. The synthesis of several neurotransmitters/modulators is regulated by O(2)-requiring rate-limiting enzymes. Consequently, hypoxia resulting from perturbations in O(2) homeostasis can affect neuronal functions by altering neurotransmitter synthesis. Two broad categories of hypoxia are frequently encountered: continuous hypoxia (CH) and intermittent hypoxia (IH). CH is often seen during high altitude sojourns, whereas IH is experienced in sleep-disordered breathing with recurrent apneas (i.e., brief, repetitive cessations of breathing). This article presents what is currently known on the effects of both forms of hypoxia on neurotransmitter levels and neurotransmitter synthesizing enzymes in the central and peripheral nervous systems.

  12. Intermittent hypoxia and cancer: Undesirable bed partners?

    Science.gov (United States)

    Almendros, Isaac; Gozal, David

    2017-08-14

    The deleterious effects of intermittent hypoxia (IH) on cancer biology have been primarily evaluated in the context of the aberrant circulation observed in solid tumors which results in recurrent intra-tumoral episodic hypoxia. From those studies, IH has been linked to an accelerated tumor progression, metastasis and resistance to therapies. More recently, the role of IH in cancer has also been studied in the context of obstructive sleep apnea (OSA), since IH is a hallmark characteristic of this condition. Such recent studies are undoubtedly adding more information regarding the role of IH on tumor malignancy. In terms of the IH patterns associated with OSA, this altered oxygenation paradigm has been recently proposed as a determinant factor in fostering cancer incidence and progression from both in vitro and in vivo experimental models. Here, we summarize all the available evidence to date linking IH effects on several types of cancer. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. The role of carbonic anhydrase IX in hypoxia control in OSCC.

    Science.gov (United States)

    Pérez-Sayáns, Mario; Supuran, Claudiu T; Pastorekova, Silvia; Suárez-Peñaranda, José Manuel; Pilar, Gayoso-Diz; Barros-Angueira, Francisco; Gándara-Rey, José Manuel; García-García, Abel

    2013-01-01

    Tumoral microenvironments play a key role in the evolution of solid tumors. Tumor hypoxia is actively involved in the promotion of genetic instability, the invasive capacity of tumor cells, metastasis, and a worsening of the clinical evolution. Endogenous hypoxia markers are controlled by hypoxia-related genes, formed by HIF-1, which is related to several target genes that involve the energy metabolism, angiogenesis, and transmembrane carbonic anhydrases (CAs), mainly CA-IX that is one of the tumor-related carbonic anhydrases. The goal of this paper is to establish the role of CA-IX as a hypoxia marker in OSCC, while analyzing its expression in this type of tumors and its relationship with several clinical and pathological parameters and prognosis, evaluating its relationship with angiogenesis, other hypoxia markers, and clarifying its role in chemotherapy and radiotherapy resistance. © 2012 John Wiley & Sons A/S.

  14. Chrysin inhibits tumor promoter-induced MMP-9 expression by blocking AP-1 via suppression of ERK and JNK pathways in gastric cancer cells.

    Directory of Open Access Journals (Sweden)

    Yong Xia

    Full Text Available Cell invasion is a crucial mechanism of cancer metastasis and malignancy. Matrix metalloproteinase-9 (MMP-9 is an important proteolytic enzyme involved in the cancer cell invasion process. High expression levels of MMP-9 in gastric cancer positively correlate with tumor aggressiveness and have a significant negative correlation with patients' survival times. Recently, mechanisms suppressing MMP-9 by phytochemicals have become increasingly investigated. Chrysin, a naturally occurring chemical in plants, has been reported to suppress tumor metastasis. However, the effects of chrysin on MMP-9 expression in gastric cancer have not been well studied. In the present study, we tested the effects of chrysin on MMP-9 expression in gastric cancer cells, and determined its underlying mechanism. We examined the effects of chrysin on MMP-9 expression and activity via RT-PCR, zymography, promoter study, and western blotting in human gastric cancer AGS cells. Chrysin inhibited phorbol-12-myristate 13-acetate (PMA-induced MMP-9 expression in a dose-dependent manner. Using AP-1 decoy oligodeoxynucleotides, we confirmed that AP-1 was the crucial transcriptional factor for MMP-9 expression. Chrysin blocked AP-1 via suppression of the phosphorylation of c-Jun and c-Fos through blocking the JNK1/2 and ERK1/2 pathways. Furthermore, AGS cells pretreated with PMA showed markedly enhanced invasiveness, which was partially abrogated by chrysin and MMP-9 antibody. Our results suggest that chrysin may exert at least part of its anticancer effect by controlling MMP-9 expression through suppression of AP-1 activity via a block of the JNK1/2 and ERK1/2 signaling pathways in gastric cancer AGS cells.

  15. Peripheral opioid antagonist enhances the effect of anti-tumor drug by blocking a cell growth-suppressive pathway in vivo.

    Directory of Open Access Journals (Sweden)

    Masami Suzuki

    Full Text Available The dormancy of tumor cells is a major problem in chemotherapy, since it limits the therapeutic efficacy of anti-tumor drugs that only target dividing cells. One potential way to overcome chemo-resistance is to "wake up" these dormant cells. Here we show that the opioid antagonist methylnaltrexone (MNTX enhances the effect of docetaxel (Doc by blocking a cell growth-suppressive pathway. We found that PENK, which encodes opioid growth factor (OGF and suppresses cell growth, is predominantly expressed in diffuse-type gastric cancers (GCs. The blockade of OGF signaling by MNTX releases cells from their arrest and boosts the effect of Doc. In comparison with the use of Doc alone, the combined use of Doc and MNTX significantly prolongs survival, alleviates abdominal pain, and diminishes Doc-resistant spheroids on the peritoneal membrane in model mice. These results suggest that blockade of the pathways that suppress cell growth may enhance the effects of anti-tumor drugs.

  16. Tumor-promoting phorbol ester transiently down-modulates the p53 level and blocks the cell cycle

    DEFF Research Database (Denmark)

    Skouv, J.; Jensen, P O; Forchhammer, J

    1994-01-01

    a decrease in the p53 mRNA level in the cell lines. Normal diploid as well as various tumor cell lines were tested. Two tumor cell lines, HeLa and A549, both containing the wild-type p53 gene, but very different levels of p53 protein, were studied in detail. In both cell lines, the level of p53 m......RNA was minimal after 9 h of exposure to PMA. After approximately 120 h, the p53 mRNA level was similar to the pretreatment level. PMA induced a similar transient decrease in the level of p53 protein in the A549 cell line. The decrease in the p53 mRNA level could not be explained by changes in the transcriptional...

  17. CRM-1 knockdown inhibits extrahepatic cholangiocarcinoma tumor growth by blocking the nuclear export of p27Kip1.

    Science.gov (United States)

    Luo, Jian; Chen, Yongjun; Li, Qiang; Wang, Bing; Zhou, Yanqiong; Lan, Hongzhen

    2016-08-01

    Cholangiocarcinoma is a deadly disease which responds poorly to surgery and conventional chemotherapy or radiotherapy. Early diagnosis is difficult due to the anatomical and biological characteristics of cholangiocarcinoma. Cyclin-dependent kinase inhibitor 1B (p27Kip1) is a cyclin‑dependent kinase inhibitor and in the present study, we found that p27Kip1 expression was suppressed in the nucleus and increased in the cytoplasm in 53 samples of cholangiocarcinoma from patients with highly malignant tumors (poorly-differentiated and tumor-node-metastsis (TNM) stage III-IV) compared with that in samples from 10 patients with chronic cholangitis. The expression of phosphorylated (p-)p27Kip1 (Ser10), one of the phosphorylated forms of p27Kip1, was increased in the patient samples with increasing malignancy and clinical stage. Coincidentally, chromosome region maintenance 1 (CRM-1; also referred to as exportin 1 or Xpo1), a critical protein responsible for protein translocation from the nucleus to the cytoplasm, was also overexpressed in the tumor samples which were poorly differentiated and of a higher clinical stage. Through specific short hairpin RNA (shRNA)-mediated knockdown of CRM-1 in the cholangiocarcinoma cell line QBC939, we identified an elevation of cytoplasmic p27Kip1 and a decrease of nuclear p27Kip1. Furthermore, the viability and colony formation ability of QBC939 cells was largely reduced with G1 arrest. Consistent with the findings of the in vitro experiments, in a xenograft mouse model, the tumors formed in the CRM-1 knockdown group were markedly smaller and weighed less than those in the control group in vivo. Taken together, these findings demonstrated that the interplay between CRM-1 and p27Kip1 may provide potentially potent biomarkers and functional targets for the development of future cholangiocarcinoma treatments.

  18. Dose escalation to high-risk sub-volumes based on non-invasive imaging of hypoxia and glycolytic activity in canine solid tumors

    DEFF Research Database (Denmark)

    Clausen, Malene M.; Hansen, Anders Elias; af Rosenschold, Per Munck

    2013-01-01

    defined by a threshold based method. FDG sub-volumes were delineated at 40% (FDG40) and 50% (FDG50) of SUVmax. The size of sub-volumes, intersection and biological target volume (BTV) were measured in a treatment planning software. By varying the average dose prescription to the tumor from 66 to 85 Gy...

  19. The Role of Hypoxia in Glioblastoma Invasion

    Directory of Open Access Journals (Sweden)

    Ana Rita Monteiro

    2017-11-01

    Full Text Available Glioblastoma multiforme (GBM, a grade IV astrocytoma, is the most common and deadly type of primary malignant brain tumor, with a patient’s median survival rate ranging from 15 to 17 months. The current treatment for GBM involves tumor resection surgery based on MRI image analysis, followed by radiotherapy and treatment with temozolomide. However, the gradual development of tumor resistance to temozolomide is frequent in GBM patients leading to subsequent tumor regrowth/relapse. For this reason, the development of more effective therapeutic approaches for GBM is of critical importance. Low tumor oxygenation, also known as hypoxia, constitutes a major concern for GBM patients, since it promotes cancer cell spreading (invasion into the healthy brain tissue in order to evade this adverse microenvironment. Tumor invasion not only constitutes a major obstacle to surgery, radiotherapy, and chemotherapy, but it is also the main cause of death in GBM patients. Understanding how hypoxia triggers the GBM cells to become invasive is paramount to developing novel and more effective therapies against this devastating disease. In this review, we will present a comprehensive examination of the available literature focused on investigating how GBM hypoxia triggers an invasive cancer cell phenotype and the role of these invasive proteins in GBM progression.

  20. Computed Tomography Demonstration of the Production and Distribution of Oxygen Gas Following Intratumoral Injection of a New Radiosensitizer (KORTUC) for Patients with Breast Cancer-Is Intratumoral Injection Not an Ideal Approach to Solve the Major Problem of Tumor Hypoxia in Radiotherapy?

    Science.gov (United States)

    Hayashi, Naoya; Ogawa, Yasuhiro; Kubota, Kei; Okino, Kazuhiro; Akima, Ryo; Morita-Tokuhiro, Shiho; Tsuzuki, Akira; Yaogawa, Shin; Nishioka, Akihito; Miyamura, Mitsuhiko

    2016-04-01

    We previously developed a new enzyme-targeting radiosensitization treatment named Kochi Oxydol-Radiation Therapy for Unresectable Carcinomas, Type II (KORTUC II), which contains hydrogen peroxide and sodium hyaluronate for injection into various types of tumors. For breast cancer treatment, the radiosensitization agent was injected into the tumor tissue twice a week under ultrasonographic guidance, immediately prior to each administration of radiation therapy. At approximately three hours after the second or third injection, computed tomography (CT) was performed to confirm the production and distribution of oxygen gas generated from the KORTUC radiosensitization agent by catalysis of peroxidases contained mainly in tumor tissue. The purpose of this study was to demonstrate that tumor hypoxia could be overcome by such a procedure and to evaluate the method of intratumoral injection in terms of confirming oxygen distribution in the target tumor tissue and around the tumor to be visualized on dedicated CT imaging. Three-dimensional reconstructed maximum intensity projection imaging of contrast-enhanced breast magnetic resonance imaging was used to compare the position of the tumor and that of the generated oxygen. Distributed oxygen gas was confirmed in the tumor tissue and around it in all 10 patients examined in the study. A region of oxygen gas was measured as an average value of -457.2 Hounsfield units (HU) as a region of interest. A slightly increased HU value compared to the density of air or oxygen was considered due to the presence of tumor tissue in the low-density area on 5-mm-thick reconstructed CT imaging. The results of this study showed that intratumoral oxygen was successfully produced by intratumoral KORTUC injection under ultrasonographic guidance, and that tumor hypoxia, which is considered a main cause of radioresistance in currently used Linac (linear accelerator) radiation therapy for malignant neoplasms, could be resolved by this method.

  1. [18F]-FMISO PET study of hypoxia in gliomas before surgery: correlation with molecular markers of hypoxia and angiogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Bekaert, Lien [CHU de Caen, Department of Neurology, Caen (France); Normandie Univ, UNICAEN, CEA, CNRS, ISTCT/CERVOxy Group, Caen (France); CHU de Caen, Department of Neurosurgery, Caen (France); CHU de Caen, Service de Neurochirurgie, Caen (France); Valable, Samuel; Collet, Solene; Bordji, Karim; Petit, Edwige; Bernaudin, Myriam [Normandie Univ, UNICAEN, CEA, CNRS, ISTCT/CERVOxy Group, Caen (France); Lechapt-Zalcman, Emmanuele [Normandie Univ, UNICAEN, CEA, CNRS, ISTCT/CERVOxy Group, Caen (France); CHU de Caen, Department of Pathology, Caen (France); Ponte, Keven [CHU de Caen, Department of Neurosurgery, Caen (France); Normandie Univ, UNICAEN, CEA, CNRS, ISTCT/CERVOxy Group, Caen (France); Constans, Jean-Marc [Normandie Univ, UNICAEN, CEA, CNRS, ISTCT/CERVOxy Group, Caen (France); CHU de Caen, Department of Neuroradiology, Caen (France); Levallet, Guenaelle [CHU de Caen, Department of Pathology, Caen (France); Branger, Pierre [CHU de Caen, Department of Neurology, Caen (France); Emery, Evelyne [CHU de Caen, Department of Neurosurgery, Caen (France); Manrique, Alain [CHU de Caen, Department of Nuclear Medicine, Caen (France); Barre, Louisa [Normandie Univ, UNICAEN, CEA, CNRS, ISTCT/LDM-TEP group, Caen (France); Guillamo, Jean-Sebastien [CHU de Caen, Department of Neurology, Caen (France); Normandie Univ, UNICAEN, CEA, CNRS, ISTCT/CERVOxy Group, Caen (France); CHU de Nimes, Department of Neurology, Nimes (France)

    2017-08-15

    Hypoxia in gliomas is associated with tumor resistance to radio- and chemotherapy. However, positron emission tomography (PET) imaging of hypoxia remains challenging, and the validation of biological markers is, therefore, of great importance. We investigated the relationship between uptake of the PET hypoxia tracer [18F]-FMISO and other markers of hypoxia and angiogenesis and with patient survival. In this prospective single center clinical study, 33 glioma patients (grade IV: n = 24, III: n = 3, and II: n = 6) underwent [18F]-FMISO PET and MRI including relative cerebral blood volume (rCBV) maps before surgery. Maximum standardized uptake values (SUVmax) and hypoxic volume were calculated, defining two groups of patients based on the presence or absence of [18F]-FMISO uptake. After surgery, molecular quantification of CAIX, VEGF, Ang2 (rt-qPCR), and HIF-1α (immunohistochemistry) were performed on tumor specimens. [18F]-FMISO PET uptake was closely linked to tumor grade, with high uptake in glioblastomas (GB, grade IV). Expression of biomarkers of hypoxia (CAIX, HIF-1α), and angiogenesis markers (VEGF, Ang2, rCBV) were significantly higher in the [18F]-FMISO uptake group. We found correlations between the degree of hypoxia (hypoxic volume and SUVmax) and expression of HIF-1α, CAIX, VEGF, Ang2, and rCBV (p < 0.01). Patients without [18F]-FMISO uptake had a longer survival time than uptake positive patients (log-rank, p < 0.005). Tumor hypoxia as evaluated by [18F]-FMISO PET is associated with the expression of hypoxia markers on a molecular level and is related to angiogenesis. [18F]-FMISO uptake is a mark of an aggressive tumor, almost always a glioblastoma. Our results underline that [18F]-FMISO PET could be useful to guide glioma treatment, and in particular radiotherapy, since hypoxia is a well-known factor of resistance. (orig.)

  2. Eukaryotic translation initiation factor 5A (eIF5A) is essential for HIF-1α activation in hypoxia

    Energy Technology Data Exchange (ETDEWEB)

    Tariq, Mohammad [Chemical Genetics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Graduate School of Science and Engineering, Saitama University, 645 Shimo-Okubo, Sakura-ku, Saitama 338-8570 (Japan); Ito, Akihiro, E-mail: akihiro-i@riken.jp [Chemical Genetics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Chemical Genomics Research Group, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Japan Agency for Medical Research and Development, AMED-CREST, 1-7-1 Otemachi, Chiyoda-ku, Tokyo, 100-0004 (Japan); Ishfaq, Muhammad; Bradshaw, Elliot [Chemical Genetics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Graduate School of Science and Engineering, Saitama University, 645 Shimo-Okubo, Sakura-ku, Saitama 338-8570 (Japan); Yoshida, Minoru [Chemical Genetics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Chemical Genomics Research Group, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Graduate School of Science and Engineering, Saitama University, 645 Shimo-Okubo, Sakura-ku, Saitama 338-8570 (Japan); Japan Agency for Medical Research and Development, AMED-CREST, 1-7-1 Otemachi, Chiyoda-ku, Tokyo, 100-0004 (Japan)

    2016-02-05

    The eukaryotic initiation factor 5A (eIF5A) is an essential protein involved in translation elongation and cell proliferation. eIF5A undergoes several post-translational modifications including hypusination and acetylation. Hypusination is indispensable for the function of eIF5A. On the other hand, the precise function of acetylation remains unknown, but it may render the protein inactive since hypusination blocks acetylation. Here, we report that acetylation of eIF5A increases under hypoxia. During extended hypoxic periods an increase in the level of eIF5A acetylation correlated with a decrease in HIF-1α, suggesting involvement of eIF5A activity in HIF-1α expression under hypoxia. Indeed, suppression of eIF5A by siRNA oligo-mediated knockdown or treatment with GC7, a deoxyhypusine synthase inhibitor, led to significant reduction of HIF-1α activity. Furthermore, knockdown of eIF5A or GC7 treatment reduced tumor spheroid formation with a concomitant decrease in HIF-1α expression. Our results suggest that functional, hypusinated eIF5A is necessary for HIF-1α expression during hypoxia and that eIF5A is an attractive target for cancer therapy. - Highlights: • Hypoxia induces acetylation of eIF5A. • Active eIF5A is necessary for HIF-1α activation in hypoxia. • Active eIF5A is important for tumor spheroid growth.

  3. Hypoxia. 3. Hypoxia and neurotransmitter synthesis

    OpenAIRE

    Kumar, Ganesh K.

    2011-01-01

    Central and peripheral neurons as well as neuroendocrine cells express a variety of neurotransmitters/modulators that play critical roles in regulation of physiological systems. The synthesis of several neurotransmitters/modulators is regulated by O2-requiring rate-limiting enzymes. Consequently, hypoxia resulting from perturbations in O2 homeostasis can affect neuronal functions by altering neurotransmitter synthesis. Two broad categories of hypoxia are frequently encountered: continuous hyp...

  4. Hypoxia-targeting antitumor prodrugs and photosensitizers

    International Nuclear Information System (INIS)

    Zhang Zhouen; Nishimoto, S.I.

    2006-01-01

    Tumor hypoxia has been identified as a key subject for tumor therapy, since hypoxic tumor cells show resistance to treatment of tumor tissues by radiotherapy, chemotherapy and phototherapy. For improvement of tumor radiotherapy, we have proposed a series of radiation-activated prodrugs that could selectively release antitumor agent 5-fluorouracil or 5-fluorodeoxyuridine under hypoxic conditions. Recently, we attempted to develop two families of novel hypoxia-targeting antitumor agents, considering that tumor-hypoxic environment is favorable to biological and photochemical reductions. The first family of prodrugs was derived from camptothecin as a potent topoisomerase I inhibitor and several bioreductive motifs. These prodrugs could be activated by NADPH-cytochrome P450 reductase or DT-diaphorase to release free camptothecin, and thereby showed hypoxia-selective cytotoxictiy towards tumor cells. These prodrugs were also applicable to the real-time monitoring of activation and antitumor effect by fluorometry. Furthermore, the camptothecin-bioreductive motif conjugates was confirmed to show an oxygen-independent DAN photocleaving activity, which could overcome a drawback of back electron transfer occurring in the photosensitized one-electron oxidation of DNA. Thus, these camptothecin derivatives could be useful to both chemotherapy and phototherapy for hypoxic tumor cells. The second family of prodrugs harnessed UV light for cancer therapy, incorporating the antitumor agent 5-fluorourcil and the photolabile 2-nitrobenzyl chromophores. The attachment of a tumor-homing cyclic peptide CNGRC was also employed to construct the prototype of tumor-targeting photoactiaved antitumor prodrug. These novel prodrugs released high yield of 5-fluorourcil upon UV irradiation at λ ex =365 nm, while being quite stable in the dark. The photoactivation mechanism was also clarified by means of nanosecond laser flash photolysis. (authors)

  5. Hypoxic Response of Tumor Tissues in a Microfluidic Environment

    Science.gov (United States)

    Morshed, Adnan; Dutta, Prashanta

    2017-11-01

    Inside a tumor tissue, cells growing further away from the blood vessel often suffer from low oxygen levels known as hypoxia. Cancer cells have shown prolonged survival in hostile hypoxic conditions by sharply changing the cellular metabolism. In this work, different stages of growth of the tumor tissue and the oxygen transport across the tissue are investigated. The tissue was modeled as a contiguous block of cells inside a microfluidic environment with nutrient transport through advection and diffusion. While oxygen uptake inside the tissue is through diffusion, ascorbate transport from the extracellular medium is addressed by a concentration dependent uptake model. By varying the experimentally observed oxygen consumption rate, different types of cancer cells and their normoxic and hypoxic stages were studied. Even when the oxygen supply in the channel is maintained at normoxic levels, our results show the onset of hypoxia within minutes inside the cellblock. Interestingly, modeled cell blocks with and without a structured basal layer showed less than 5% variation in hypoxic response in chronic hypoxia. Results also indicate that the balance of cell survival and growth are affected by the flow rate of nutrients and the oxygen consumption rate. This work was supported in part by the National Science Foundation under Grant No. DMS 1317671.

  6. Stromal Expression of Hypoxia Regulated Proteins Is an Adverse Prognostic Factor in Colorectal Carcinomas

    Directory of Open Access Journals (Sweden)

    Arjen H. G. Cleven

    2007-01-01

    Full Text Available Background: Hypoxia modifies the phenotype of tumors in a way that promotes tumor aggressiveness and resistance towards chemotherapy and radiotherapy. However, the expression and influence of hypoxia-regulated proteins on tumor biology are not well characterized in colorectal tumors. We studied the role of protein expression of hypoxia-inducible factor (HIF-1α, HIF-2α, carbonic anhydrase 9 (CA9 and glucose transporter 1 (GLUT1 in patients with colorectal adenocarcinomas. Methods: Expression of HIF-1α, HIF-2α, CA9 and GLUT1 was quantified by immunohistochemistry in 133 colorectal adenocarcinomas. The expression of hypoxia markers was correlated with clinicopathological variables and overall patient survival. Results: Expression of these hypoxia markers was detected in the epithelial compartment of the tumor cells as well as in tumor-associated stromal cells. Although tumor cells frequently showed expression of one or more of the investigated hypoxia markers, no correlation among these markers or with clinical response was found. However, within the tumor stroma, positive correlations between the hypoxia markers HIF-2α, CA9 and GLUT1 were observed. Furthermore expression of HIF-2α and CA9 in tumor-associated stroma were both associated with a significantly reduced overall survival. In the Cox proportional hazard model, stromal HIF-2α expression was an independent prognostic factor for survival. Conclusion: These observations show, that expression of hypoxia regulated proteins in tumor-associated stromal cells, as opposed to their expression in epithelial tumor cells, is associated with poor outcome in colorectal cancer. This study suggests that tumor hypoxia may influence tumor-associated stromal cells in a way that ultimately contributes to patient prognosis.

  7. S-adenosylmethionine blocks osteosarcoma cells proliferation and invasion in vitro and tumor metastasis in vivo: therapeutic and diagnostic clinical applications

    International Nuclear Information System (INIS)

    Parashar, Surabhi; Cheishvili, David; Arakelian, Ani; Hussain, Zahid; Tanvir, Imrana; Khan, Haseeb Ahmed; Szyf, Moshe; Rabbani, Shafaat A

    2015-01-01

    Osteosarcoma (OS) is an aggressive and highly metastatic form of primary bone cancer affecting young children and adults. Previous studies have shown that hypomethylation of critical genes is driving metastasis. Here, we examine whether hypermethylation treatment can block OS growth and pulmonary metastasis. Human OS cells LM-7 and MG-63 were treated with the ubiquitous methyl donor S-adenosylmethionine (SAM) or its inactive analog S-adenosylhomocystine (SAH) as control. Treatment with SAM resulted in a dose-dependent inhibition of tumor cell proliferation, invasion, cell migration, and cell cycle characteristics. Inoculation of cells treated with 150 μmol/L SAM for 6 days into tibia or via intravenous route into Fox Chase severe combined immune deficient (SCID) mice resulted in the development of significantly smaller skeletal lesions and a marked reduction in pulmonary metastasis as compared to control groups. Epigenome wide association studies (EWAS) showed differential methylation of several genes involved in OS progression and prominent signaling pathways implicated in bone formation, wound healing, and tumor progression in SAM-treated LM-7 cells. Real-time polymerase chain reaction (qPCR) analysis confirmed that SAM treatment blocked the expression of several prometastatic genes and additional genes identified by EWAS analysis. Immunohistochemical analysis of normal human bone and tissue array from OS patients showed significantly high levels of expression of one of the identified gene platelet-derived growth factor alpha (PDGFA). These studies provide a possible mechanism for the role of DNA demethylation in the development and metastasis of OS to provide a rationale for the use of hypermethylation therapy for OS patients and identify new targets for monitoring OS development and progression

  8. Hypoxia and Hypoxia Mimetics Decrease Aquaporin 5 (AQP5) Expression through Both Hypoxia Inducible Factor-1α and Proteasome-Mediated Pathways

    Science.gov (United States)

    Kawedia, Jitesh D.; Yang, Fan; Sartor, Maureen A.; Gozal, David; Czyzyk-Krzeska, Maria; Menon, Anil G.

    2013-01-01

    The alveolar epithelium plays a central role in gas exchange and fluid transport, and is therefore critical for normal lung function. Since the bulk of water flux across this epithelium depends on the membrane water channel Aquaporin 5 (AQP5), we asked whether hypoxia had any effect on AQP5 expression. We show that hypoxia causes a significant (70%) decrease in AQP5 expression in the lungs of mice exposed to hypoxia. Hypoxia and the hypoxia mimetic, cobalt, also caused similar decreases in AQP5 mRNA and protein expression in the mouse lung epithelial cell line MLE-12. The action of hypoxia and cobalt on AQP5 transcription was demonstrated by directly quantifying heternonuclear RNA by real-time PCR. Dominant negative mutants of Hypoxia Inducible Factor (HIF-1α) and HIF-1α siRNA blocked the action of cobalt, showing that HIF-1α is a key component in this mechanism. The proteasome inhibitors, lactacystin or proteasome inhibitor-III completely abolished the effect of hypoxia and cobalt both at the protein and mRNA level indicating that the proteasome pathway is probably involved not only for the stability of HIF-1α protein, but for the stability of unidentified transcription factors that regulate AQP5 transcription. These studies reveal a potentially important physiological mechanism linking hypoxic stress and membrane water channels. PMID:23469202

  9. Antibodies against amino acids 1-15 of tumor necrosis factor block its binding to cell-surface receptor.

    OpenAIRE

    Socher, S H; Riemen, M W; Martinez, D; Friedman, A; Tai, J; Quintero, J C; Garsky, V; Oliff, A

    1987-01-01

    Human tumor necrosis factor (hTNF) mediates a variety of biologic activities, which are dependent on the attachment of hTNF to cell-surface receptors. To identify regions of the hTNF protein involved in binding hTNF to its receptor, we prepared five synthetic peptides [hTNF-(1-15), hTNF-(1-31), hTNF-(65-79), hTNF-(98-111), and hTNF-(124-141)] and two hydroxylamine cleavage fragments [hTNF-(1-39) and hTNF-(40-157)] of hTNF. The hTNF-synthetic peptides and hTNF fragments were tested in hTNF rec...

  10. Ultrasound Evaluation of the Entheses in Daily Clinical Practice during Tumor Necrosis Factor-α Blocking Therapy in Patients with Ankylosing Spondylitis.

    Science.gov (United States)

    Wink, Fréke; Bruyn, George A; Maas, Fiona; Griep, Ed N; van der Veer, Eveline; Bootsma, Hendrika; Brouwer, Elisabeth; Arends, Suzanne; Spoorenberg, Anneke

    2017-05-01

    To assess structural and inflammatory ultrasound (US) lesions of entheses in ankylosing spondylitis (AS) patients with active disease and to evaluate inflammatory lesions after 6 months of tumor necrosis factor (TNF-α) blocking therapy, in daily clinical practice. Consecutive patients with AS were clinically evaluated and underwent US examination of 9 bilateral entheses before and after 6 months of TNF-α blocking therapy. US examination included the following as inflammatory lesions: bone erosions/cortical irregularities, enthesophytes, calcifications as structural lesions; adjacent bursitis, effusion, increased tendon hypoechogenicity or thickness; and positive power Doppler (PD) signal. At baseline, 105 (95%) of 111 included patients showed US abnormalities. Structural lesions were seen in 74 patients (67%) and inflammatory lesions in 88 (79%). Enthesophytes and positive PD signal were the most prevalent structural and inflammatory lesions, respectively. Most lesions were found at the lower extremities. Additionally, inflammatory lesions occurred at the lateral epicondyle of the elbow. Patients with structural lesions at baseline were significantly older, had longer disease duration, higher modified Stoke AS Spine score, and higher C-reactive protein. Individually, there was a great diversity in changes of inflammatory entheseal lesions during treatment, but on the group level no significant decrease was found. This prospective observational cohort study in daily clinical practice shows a high prevalence of structural and inflammatory US lesions in AS patients with longstanding and active disease. Positive PD signal was the most common inflammatory feature. No significant change in inflammatory US lesions was found after 6 months of TNF-α blocking therapy.

  11. Insulin/insulin like growth factors in cancer: new roles for the aryl hydrocarbon receptor, tumor resistance mechanisms and new blocking strategies

    Directory of Open Access Journals (Sweden)

    Travis B Salisbury

    2015-02-01

    Full Text Available The insulin-like growth factor 1 receptor (IGF1R and the insulin receptor (IR are receptor tyrosine kinases (RTKs that are expressed in cancer cells. The results of different studies indicate that tumor proliferation and survival is dependent on the IGF1R and IR, and that their inhibition leads to reductions in proliferation and increases in cell death. Molecular targeting therapies that have been used in solid tumors include: anti-IGF1R antibodies, anti-IGF1/IGF2 antibodies and small molecule inhibitors that suppress IGF1R and IR kinase activity. New advances in the molecular basis of anti-IGF1R blocking antibodies reveal they are biased agonists and promote the binding of IGF1 to integrin β3 receptors in some cancer cells. Our recent reports indicate that pharmacological aryl hydrocarbon receptor (AHR ligands inhibit breast cancer cell responses to IGFs, suggesting that targeting AHR may have benefit in cancers whose proliferation and survival are dependent on insulin/IGF signaling. Novel aspects of IGF1R/IR in cancer, such as biased agonism, integrin β3 signaling, AHR and new therapeutic targeting strategies will be discussed.

  12. Selective vulnerability in brain hypoxia

    DEFF Research Database (Denmark)

    Cervos-Navarro, J.; Diemer, Nils Henrik

    1991-01-01

    Neuropathology, selective vulnerability, brain hypoxia, vascular factors, excitotoxicity, ion homeostasis......Neuropathology, selective vulnerability, brain hypoxia, vascular factors, excitotoxicity, ion homeostasis...

  13. Hypoxia positron emission tomography imaging: combining information on perfusion and tracer retention to improve hypoxia specificity

    DEFF Research Database (Denmark)

    Busk, Morten; Munk, Ole L; Jakobsen, Steen S

    2017-01-01

    BACKGROUND: Static positron emission tomography (PET) allows mapping of tumor hypoxia, but low resolution and slow tracer retention/clearance results in poor image contrast and the risk of missing areas where hypoxic cells and necrosis are intermixed. Fully dynamic PET may improve accuracy but scan...

  14. Protein S-glutathionylation induced by hypoxia increases hypoxia-inducible factor-1α in human colon cancer cells.

    Science.gov (United States)

    Jeon, Daun; Park, Heon Joo; Kim, Hong Seok

    2018-01-01

    Hypoxia is a common characteristic of many types of solid tumors. Intratumoral hypoxia selects for tumor cells that survive in a low oxygen environment, undergo epithelial-mesenchymal transition, are more motile and invasive, and show gene expression changes driven by hypoxia-inducible factor-1α (HIF-1α) activation. Therefore, targeting HIF-1α is an attractive strategy for disrupting multiple pathways crucial for tumor growth. In the present study, we demonstrated that hypoxia increases the S-glutathionylation of HIF-1α and its protein levels in colon cancer cells. This effect is significantly prevented by decreasing oxidized glutathione as well as glutathione depletion, indicating that S-glutathionylation and the formation of protein-glutathione mixed disulfides is related to HIF-1α protein levels. Moreover, colon cancer cells expressing glutaredoxin 1 are resistant to inducing HIF-1α and expressing hypoxia-responsive genes under hypoxic conditions. Therefore, S-glutathionylation of HIF-1α induced by tumor hypoxia may be a novel therapeutic target for the development of new drugs. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Hypoxia-induced metastasis model in embryonic zebrafish

    DEFF Research Database (Denmark)

    Rouhi, Pegah; Jensen, Lasse D.; Cao, Ziquan

    2010-01-01

    of the early events of tumor cell invasion and dissemination in living animals. We recently developed a zebrafish metastasis model to dissect the detailed events of hypoxia-induced tumor cell invasion and metastasis in association with angiogenesis at the single-cell level. In this model, fluorescent Di...

  16. Visualizing the antivascular effect of bortezomib on the hypoxic tumor microenvironment.

    Science.gov (United States)

    Sun, Xiaorong; Ackerstaff, Ellen; He, Fuqiu; Xing, Ligang; Hsiao, Hung Tsung; Koutcher, Jason A; Ling, C Clifton; Li, Gloria C

    2015-10-27

    Bortezomib, a novel proteasome inhibitor, has been approved for treating multiple myeloma and mantle cell lymphoma and studied pre-clinically and clinically for solid tumors. Preferential cytotoxicity of bortezomib was found toward hypoxic tumor cells and endothelial cells in vitro. The purpose of this study is to investigate the role of a pretreatment hypoxic tumor microenvironment on the effects of bortezomib in vitro and ex vivo, and explore the feasibility of dynamic contrast enhanced magnetic resonance imaging (DCE MRI) to noninvasively evaluate the biological effects of bortezomib. It was shown in vitro by Western blot, flow cytometry, and ELISA that bortezomib accumulated HIF-1α in non-functional forms and blocks its hypoxia response in human colorectal cancer cell lines. Ex vivo experiments were performed with fluorescent immunohistochemical staining techniques using multiple endogenous and exogenous markers to identify hypoxia (pimonidazole, HRE-TKeGFP), blood flow/permeability (Hoechst 33342), micro-vessels (CD31 and SMA), apoptosis (cleaved caspase 3) and hypoxia response (CA9). After bortezomib administration, overall apoptosis index was significantly increased and blood perfusion was dramatically decreased in tumor xenografts. More importantly, apoptosis signals were found preferentially located in moderate and severe pretreatment hypoxic regions in both tumor and endothelial cells. Meanwhile, DCE MRI examinations showed that the tumor blood flow and permeability decreased significantly after bortezomib administration. The present study revealed that bortezomib reduces tumor hypoxia response and blood perfusion, thus, presenting antivascular properties. It will be important to determine the hypoxic/perfusion status pre- and during treatment at further translational studies.

  17. Hypoxia and Mucosal Inflammation

    Science.gov (United States)

    Colgan, Sean P.; Campbell, Eric L.; Kominsky, Douglas J.

    2016-01-01

    Sites of inflammation are defined by significant changes in metabolic activity. Recent studies have suggested that O2 metabolism and hypoxia play a prominent role in inflammation so-called “inflammatory hypoxia,” which results from a combination of recruited inflammatory cells (e.g., neutrophils and monocytes), the local proliferation of multiple cell types, and the activation of multiple O2-consuming enzymes during inflammation. These shifts in energy supply and demand result in localized regions of hypoxia and have revealed the important function off the transcription factor HIF (hypoxia-inducible factor) in the regulation of key target genes that promote inflammatory resolution. Analysis of these pathways has provided multiple opportunities for understanding basic mechanisms of inflammation and has defined new targets for intervention. Here, we review recent work addressing tissue hypoxia and metabolic control of inflammation and immunity. PMID:27193451

  18. Three dimensional variability in patient positioning using bite block immobilization in 3D-conformal radiation treatment for ENT-tumors

    International Nuclear Information System (INIS)

    Willner, Jochen; Haedinger, Ulrich; Neumann, Michael; Schwab, Franz J.; Bratengeier, Klaus; Flentje, Michael

    1997-01-01

    Background and purpose: The aim of this prospective study was to analyze the three-dimensional (3D) reproducibility of the isocenter position and of patient positioning with the use of bite block immobilization by means of a simple verification procedure for a complex beam arrangement applied for ENT-tumors. Materials and methods: We analyzed the positioning data of 29 consecutive patients treated for ENT-tumors at the Department of Radiotherapy and Oncology of the University of Wuerzburg. A total of 136 treatment sessions were analyzed. Patients were positioned and immobilized using an individualized bite block system and a head and neck support. A complex beam arrangement was applied combining two offset rotational and two oblique wedge fields on a 5 MV linear accelerator. Orthogonal verification films were taken once weekly. Four to six film pairs per patient were obtained (during 4-6 weeks) with a mean number of 4.7 film pairs per patient. These were compared to the corresponding orthogonal simulator films taken during primary simulation. Deviations of the verified isocenter from isocenter on the simulator film were measured and analyzed in three dimensions in terms of overall, systematic and random categories. A 3D-deviation vector was calculated from these 3D data as well as a 2D-deviation vector (for comparison with literature data) from the lateral verification films. Results: The overall setup deviation showed standard deviations (SD) of 2.5, 2.7 and 3.1 mm along the cranio-caudal, anterior-posterior and medio-lateral axes, respectively. The random component ranged from SD 1.9 to 2.1 mm and the systematic component ranged from SD 1.8 to 2.2 mm. The mean length of the 3D-vector was 3.1 mm for the systematic as well as the random component. Ninety percent of 3D systematic and random deviations were less than 5 mm. The mean length of the 2D-vector was 2.4 mm for the random component and 2.2 mm for the systematic component. Ninety percent of 2D-random and

  19. The Human Homolog of Drosophila Headcase Acts as a Tumor Suppressor through Its Blocking Effect on the Cell Cycle in Hepatocellular Carcinoma.

    Directory of Open Access Journals (Sweden)

    Jun Wang

    Full Text Available The molecular pathogenesis of hepatocellular carcinoma (HCC is heterogeneous and extremely complex. Thus, for individual molecular targeted therapy, novel molecular markers are needed. The abnormal expression of the human homolog of Drosophila headcase (HECA homo has been found in pancreatic, colorectal, and oral squamous cell carcinoma. Studies of oral squamous cell carcinoma have also demonstrated that the HECA homo protein can be negatively controlled by the Wnt-pathway and transcription factor 4 (TCF4 and can slow cell division by interacting with cyclins and CDKs. However, the role of HECA in HCC has not been reported elsewhere. Here, immunohistochemical analysis revealed that the downregulation of HECA homo protein occurred in 71.0% (66/93 of HCC cases and was positively correlated with a poorly differentiated grade, high serum AFP level, liver cirrhosis and large tumor size. The expression of HECA homo was detected in five live cell lines. In vitro, the overexpression of HECA homo in HepG2, Huh-7 and MHCC-97H cells could inhibit cell proliferation and colony formation and induce G1 phase arrest. In contrast, the downregulation of HECA homo could promote cell proliferation, colony formation and the cell cycle process. However, neither the overexpression nor downregulation of HECA homo in the three cell lines could affect cell migration or invasion. Collectively, HECA homo is regularly expressed in normal live cells, and the HECA homo protein level is heterogeneously altered in HCC, but the downregulation of HECA homo is more common and positively correlated with several malignant phenotypes. The HECA homo protein can slow cell proliferation to some extent primarily through its blocking effect on the cell cycle. Hence, the HECA homo protein may act as a tumor suppressor in HCC and might be a potential molecular marker for diagnostic classification and targeted therapy in HCC.

  20. Simultaneous study by PET/CT of the proliferation, metabolism and tumoral hypoxia before and during an exclusive radiotherapy (R.T.) in patients suffering of anon at small cells bronco-pulmonary cancer (N.S.C.B.P.C.); Etude simultanee par TEP/TDM de la proliferation, du metabolisme et de l'hypoxie tumorale avant et pendant une radiotherapie exclusive (RT) chez les patients atteints d'un cancer broncho-pulmonaire non a petites cellules (CBPNPC)

    Energy Technology Data Exchange (ETDEWEB)

    Vera, P.; Edet-Sanson, A.; Bohn, P.; Salles, A.; Hapdey, S.; Gardin, I. [Centre Becquerel, QuantIF LITIS EA4108, service de medecine nucleaire, 76 - Rouen (France); Menard, J.F. [CHU de Rouen, QuantIF LITIS EA4108, service de statistique, 76 (France); Thiberville, L. [CHU de Rouen, clinique pneumologique, QuantIF LITIS EA4108, 76 (France); Dubray, B. [Centre Becquerel, QuantIF LITIS EA4108, service de radiotherapie, 76 - Rouen (France)

    2010-07-01

    Purpose: Simultaneous in vivo study by PET/CT of proliferation, metabolism and tumor hypoxia modifications before and during radiotherapy has never been realised in patients suffering of a bronco-pulmonary non at small cells cancer (C.B.P.N.P.C.). Conclusions: the quasi simultaneous realisation (in 4 to 7 days) of three PET/CT images before and during radiotherapy, in patients suffering of a C.B.P.N.P.C. appears feasible. At 2 Gy of the radiotherapy, proliferation reduces quickly, in the tumor and the mediastinum ganglions. this reduction appears more rapidly than the metabolism decrease. Hypoxia is more important in the tumor than in the ganglions, but does not vary during irradiation. (N.C.)

  1. Feasibility of a subcutaneously administered block/homo-mixed polyplex micelle as a carrier for DNA vaccination in a mouse tumor model.

    Science.gov (United States)

    Cui, Lin; Osada, Kensuke; Imaizumi, Akira; Kataoka, Kazunori; Nakano, Kenji

    2015-05-28

    In this study, the potential of DNA vaccine by subcutaneously (s.c.) administered block/homo-mixed (B/H) polyplex micelles carrying genes encoding tumor-associated antigen SART3 as well as CD40L and GM-CSF was compared with the intraperitoneal (i.p.) and intravenous (i.v.) administrations or electroporation method. Confocal laser microscopy revealed high localization of polyplexes in groin lymph nodes and local skin tissues after s.c. administration, and in the mesenteric lymph nodes, liver, and spleen after i.p. administration, but not after i.v. administration. Real-time RT-PCR and immunohistochemistry showed transgene expression in the above organs by s.c. and i.p. administered B/H polyplex micelles, but not by the i.v. administration or electroporation. Polyplex-carried DNA vaccines significantly decreased the weight of subcutaneous CT26 tumors in mice compared to the mock (2.9±0.8 vs 6.4±2.6 g, P<0.05 for s.c.; 3.2±1.1 vs 4.7±2.1 g, P<0.05 for i.p. administration). The survival rate was improved by s.c. administration of the DNA vaccine (P<0.05) and by the i.p. administered DNA vaccine (P<0.01) compared with that of the mock controls in mice with peritoneally disseminated CT26 cancer. Such therapeutic effects were not observed by the naked DNA, i.v. administered DNA vaccine or electroporation. CTL and NK cell activities of splenocytes and infiltration of CD11c(+) DCs, and CD4(+) and CD8a(+) T cells into tumor tissues were upregulated in the s.c. administered DNA vaccine group (P<0.05), which was consistent with i.p. administration. No abnormal findings in local injection sites, body weight, or blood examinations were observed by s.c. or i.p. administration of polyplex micelles, whereas proinflammatory cytokine production was minimized in visceral organs with the s.c. administered polyplex-carried DNA vaccine. In conclusion, s.c. administration of B/H polyplex micelles may be a safe and useful modality for DNA vaccination. Copyright © 2015 Elsevier B

  2. Sensitization of Tumor to {sup 212}Pb Radioimmunotherapy by Gemcitabine Involves Initial Abrogation of G2 Arrest and Blocked DNA Damage Repair by Interference With Rad51

    Energy Technology Data Exchange (ETDEWEB)

    Yong, Kwon Joong; Milenic, Diane E.; Baidoo, Kwamena E. [Radioimmune and Inorganic Chemistry Section, Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States); Brechbiel, Martin W., E-mail: martinwb@mail.nih.gov [Radioimmune and Inorganic Chemistry Section, Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States)

    2013-03-15

    Purpose: To elucidate the mechanism of the therapeutic efficacy of targeted α-particle radiation therapy using {sup 212}Pb-TCMC-trastuzumab together with gemcitabine for treatment of disseminated peritoneal cancers. Methods and Materials: Mice bearing human colon cancer LS-174T intraperitoneal xenografts were pretreated with gemcitabine, followed by {sup 212}Pb-TCMC-trastuzumab and compared with controls. Results: Treatment with {sup 212}Pb-TCMC-trastuzumab increased the apoptotic rate in the S-phase-arrested tumors induced by gemcitabine at earlier time points (6 to 24 hours). {sup 212}Pb-TCMC-trastuzumab after gemcitabine pretreatment abrogated G2/M arrest at the same time points, which may be associated with the inhibition of Chk1 phosphorylation and, in turn, cell cycle perturbation, resulting in apoptosis. {sup 212}Pb-TCMC-trastuzumab treatment after gemcitabine pretreatment caused depression of DNA synthesis, DNA double-strand breaks, accumulation of unrepaired DNA, and down-regulation of Rad51 protein, indicating that DNA damage repair was blocked. In addition, modification in the chromatin structure of p21 may be associated with transcriptionally repressed chromatin states, indicating that the open structure was delayed at earlier time points. Conclusion: These findings suggest that the cell-killing efficacy of {sup 212}Pb-TCMC-trastuzumab after gemcitabine pretreatment may be associated with abrogation of the G2/M checkpoint, inhibition of DNA damage repair, and chromatin remodeling.

  3. Sensitization of Tumor to 212Pb Radioimmunotherapy by Gemcitabine Involves Initial Abrogation of G2 Arrest and Blocked DNA Damage Repair by Interference With Rad51

    International Nuclear Information System (INIS)

    Yong, Kwon Joong; Milenic, Diane E.; Baidoo, Kwamena E.; Brechbiel, Martin W.

    2013-01-01

    Purpose: To elucidate the mechanism of the therapeutic efficacy of targeted α-particle radiation therapy using 212 Pb-TCMC-trastuzumab together with gemcitabine for treatment of disseminated peritoneal cancers. Methods and Materials: Mice bearing human colon cancer LS-174T intraperitoneal xenografts were pretreated with gemcitabine, followed by 212 Pb-TCMC-trastuzumab and compared with controls. Results: Treatment with 212 Pb-TCMC-trastuzumab increased the apoptotic rate in the S-phase-arrested tumors induced by gemcitabine at earlier time points (6 to 24 hours). 212 Pb-TCMC-trastuzumab after gemcitabine pretreatment abrogated G2/M arrest at the same time points, which may be associated with the inhibition of Chk1 phosphorylation and, in turn, cell cycle perturbation, resulting in apoptosis. 212 Pb-TCMC-trastuzumab treatment after gemcitabine pretreatment caused depression of DNA synthesis, DNA double-strand breaks, accumulation of unrepaired DNA, and down-regulation of Rad51 protein, indicating that DNA damage repair was blocked. In addition, modification in the chromatin structure of p21 may be associated with transcriptionally repressed chromatin states, indicating that the open structure was delayed at earlier time points. Conclusion: These findings suggest that the cell-killing efficacy of 212 Pb-TCMC-trastuzumab after gemcitabine pretreatment may be associated with abrogation of the G2/M checkpoint, inhibition of DNA damage repair, and chromatin remodeling

  4. Anti-tumor effects of a novel retinoic acid metabolism blocking agent VN/14-1 in the N-methyl-N-nitrosourea-induced rat mammary carcinoma model and its effects on the uterus.

    Science.gov (United States)

    Goss, Paul E; Qi, Shangle; Hu, Haiqing; Gediya, Lalji K; Purushottamachar, Puranik; Godbole, Abhijit M; Njar, Vincent C O

    2012-05-01

    VN/14-1 [4-(±)-(1H-Imidazol-1-yl)-(E)-retinoic acid], a novel retinoic acid metabolism blocking agent (RAMBA), works by inhibiting the breakdown of all-trans-retinoic acid. The purpose of this study was to evaluate the anti-tumor effects of VN/14-1 on the N-methyl-N-nitrosourea (MNU)-induced rat mammary carcinoma model, and peripheral organ effects on the uteri of immature ovariectomized (OVX) rats. In tumor burden experiments, after 56 days of administration of VN/14-1 5, 10, and 20 mg/kg/day, significant tumor reductions in mean tumor weight of 19.1, 34.4, and 44.3%, compared to tumors in control animals occurred. Cumulative tumor growth was also significantly slower in a dose-dependent manner in groups receiving 5, 10, and 20 mg/kg/day of VN/14-1 compared to growth rates in the control group. Tumor apoptosis was significant increases in animals treated with 5, 10, and 20 mg/kg/day of VN/14-1. In uterotrophic experiments, immature OVX rats given VN/14-1 significantly reduced uterine weight and blocked endometrial stimulation induced by unopposed β-estradiol (E2). In both rat models, adverse toxicities included weakness, anorexia, and reduction in body weight in the groups given the highest dose of 20 mg/kg/day. In summary, VN/14-1 inhibited tumor growth in the MNU-induced estrogen receptor (ER)-positive rat mammary tumor model, and antagonized the stimulatory effect of estrogens on the uterus. The studies suggest that VN/14-1 may be a useful novel therapy for ER-positive breast cancer.

  5. Preclinical evaluation and validation of [18F]HX4, a promising hypoxia marker for PET imaging

    NARCIS (Netherlands)

    Dubois, L.J.; Lieuwes, N.G.; Janssen, M.H.; Peeters, W.J.M.; Windhorst, A.D.; Walsh, J.C.; Kolb, H.C.; Ollers, M.C.; Bussink, J.; Dongen, G.A. van; Kogel, A.J. van der; Lambin, P.

    2011-01-01

    Hypoxia has been shown to be an important microenvironmental parameter influencing tumor progression and treatment efficacy. Patient guidance for hypoxia-targeted therapy requires evaluation of tumor oxygenation, preferably in a noninvasive manner. The aim of this study was to evaluate and validate

  6. Vascular abnormalities associated with acute hypoxia in human melanoma xenografts

    International Nuclear Information System (INIS)

    Simonsen, Trude G.; Gaustad, Jon-Vidar; Leinaas, Marit N.; Rofstad, Einar K.

    2012-01-01

    Background and purpose: The fraction of hypoxic cells has been shown to differ substantially among human tumors of the same histological type. In this study, a window chamber model was used to identify possible mechanisms leading to the development of highly different hypoxic fractions in A-07 and R-18 human melanoma xenografts. Materials and methods: Chronic and acute hypoxia was assessed in intradermal tumors using an immunohistochemical and a radiobiological assay. Functional and morphological parameters of the vascular networks of tumors growing in dorsal window chambers were assessed with intravital microscopy. Results: R-18 tumors showed significantly higher hypoxic fractions than A-07 tumors, and the difference was mostly due to acute hypoxia. Compared to A-07 tumors, R-18 tumors showed low vascular densities, low vessel diameters, long vessel segments, low blood flow velocities, frequent fluctuations in blood flow, and a high fraction of narrow vessels with absent or very low and varying flux of red blood cells. Conclusion: The high fraction of acute hypoxia in R-18 tumors was a consequence of frequent fluctuations in blood flow and red blood cell flux combined with low vascular density. The fluctuations were most likely caused by high geometric resistance to blood flow in the tumor microvasculature.

  7. Hypoxia Activated Prodrugs: Factors Influencing Design and Development.

    Science.gov (United States)

    Liang, Dinghua; Miller, Graham H; Tranmer, Geoffrey K

    2015-01-01

    Hypoxia in tumor cells is characterized by a lack of oxygen resulting from reduced blood supply to the surrounding tissue, and is a common characteristic of solid tumors as a consequence of rapid cell growth. Hypoxia in tumors is a predictor of both resistance to chemotherapy and of a metastatic/aggressive form of cancer, and as a result, development of cancer therapies which target hypoxia is of vital importance. One such targeting strategy is the development of hypoxia-activated prodrugs (HAP) which can preferentially release chemotherapeutic agents within hypoxic tumor regions. This targeting strategy is accomplished by attaching a hypoxia activated trigger to a chemotherapeutic agent and under oxygen-poor conditions, the agent (effector) is released into the tumor, while remaining intact in normal tissue, and leaving non-hypoxic cells undamaged. Overall, this strategy can achieve an increased therapeutic benefit over conventional small molecule chemotherapeutic treatments by concentrating the drugs within hypoxic tumor environments, while simultaneously reducing the side-effects and toxicity issues that surround the systemic distribution of traditional drugs on normoxic cells. In this review, we will describe the factors that should be considered when designing an effective HAP, such as the mechanism of prodrug action, the elements that influence the rational design of HAP (i.e. reduction potential), and the activating enzymes of HAP. As part of this description, we will utilize select examples from the literature to reinforce these factors, and make a case for the intelligent design of new HAPs, leading to the development of novel hypoxia targeting chemotherapeutic agents.

  8. Inhibition of hypoxia inducible factor 1 and topoisomerase with acriflavine sensitizes perihilar cholangiocarcinomas to photodynamic therapy

    NARCIS (Netherlands)

    Weijer, Ruud; Broekgaarden, Mans; Krekorian, Massis; Alles, Lindy K.; van Wijk, Albert C.; Mackaaij, Claire; Verheij, Joanne; van der Wal, Allard C.; van Gulik, Thomas M.; Storm, Gert; Heger, Michal

    2016-01-01

    Photodynamic therapy (PDT) induces tumor cell death by oxidative stress and hypoxia but also survival signaling through activation of hypoxia-inducible factor 1 (HIF-1). Since perihilar cholangiocarcinomas are relatively recalcitrant to PDT, the aims were to (1) determine the expression levels of

  9. Inhibition of hypoxia inducible factor 1 and topoisomerase with acriflavine sensitizes perihilar cholangiocarcinomas to photodynamic therapy

    NARCIS (Netherlands)

    Weijer, R.; Broekgaarden, M.; Krekorian, M.; Alles, L.K.; van Wijk, A.C; Mackaaij, C.; Verheij, J.; van der Wal, A.C.; van Gullik, T.M.; Storm, Gerrit; Heger, M.

    2016-01-01

    Background: Photodynamic therapy (PDT) induces tumor cell death by oxidative stress and hypoxia but also survival signaling through activation of hypoxia-inducible factor 1 (HIF-1). Since perihilar cholangiocarcinomas are relatively recalcitrant to PDT, the aims were to (1) determine the expression

  10. The Linkage between Breast Cancer, Hypoxia, and Adipose Tissue

    Directory of Open Access Journals (Sweden)

    Linda K. Rausch

    2017-09-01

    Full Text Available ObjectiveThe development of breast cancer cells is linked to hypoxia. The hypoxia-induced factor HIF-1α influences metastasis through neovascularization. Hypoxia seems to decrease the responsiveness to hormonal treatment due to loss of estrogen receptors (ERs. Obesity is discussed to increase hypoxia in adipocytes, which promotes a favorable environment for tumor cells in mammary fat tissue, whereas, tumor cells profit from good oxygen supply and are influenced by its deprivation as target regions within tumors show. This review gives an overview of the current state on research of hypoxia and breast cancer in human adipose tissue.MethodsA systematic literature search was conducted on PubMed (2000–2016 by applying hypoxia and/or adipocytes and breast cancer as keywords. Review articles were excluded as well as languages other than English or German. There was no restriction regarding the study design or type of breast cancer. A total of 35 papers were found. Eight studies were excluded due to missing at least two of the three keywords. One paper was removed due to Russian language, and one was dismissed due to lack of adherence. Seven papers were identified as reviews. After applying exclusion criteria, 18 articles were eligible for inclusion.ResultsTwo articles describe the impairment of mammary epithelial cell polarization through hypoxic preconditioning. A high amount of adipocytes enhances cancer progression due to the increased expression of HIF-1α which causes the loss of ER α protein as stated in four articles. Four articles analyzed that increased activation of HIF’s induces a series of transcriptions resulting in tumor angiogenesis. HIF inhibition, especially when combined with cytotoxic chemotherapy, holds strong potential for tumor suppression as stated in further four articles. In two articles there is evidence of a strong connection between hypoxia, oxidative stress and a poor prognosis for breast cancer via HIF regulated

  11. Hypoxia and Angiogenesis in Endometrioid Endometrial Carcinogenesis

    Directory of Open Access Journals (Sweden)

    Nicole Horrée

    2007-01-01

    Full Text Available Background: Hypoxia-inducible factor 1α (HIF-1α plays an essential role in the adaptive response of cells to hypoxia, triggering biologic events associated with aggressive tumor behavior. Methods: Expression of HIF-1α and proteins in the HIF-1α pathway (Glut-1, CAIX, VEGF in paraffin-embedded specimens of normal (n = 17, premalignant (n = 17 and endometrioid endometrial carcinoma (n = 39 was explored by immunohistochemistry, in relation to microvessel density (MVD. Results: HIF-1α overexpression was absent in inactive endometrium but present in hyperplasia (61% and carcinoma (87%, with increasing expression in a perinecrotic fashion pointing to underlying hypoxia. No membranous expression of Glut-1 and CAIX was noticed in inactive endometrium, in contrast with expression in hyperplasia (Glut-1 0%, CAIX 61%, only focal and diffuse and carcinoma (Glut-1 94.6%, CAIX 92%, both mostly perinecrotically. Diffuse HIF-1α was accompanied by activation of downstream targets. VEGF was significantly higher expressed in hyperplasias and carcinomas compared to inactive endometrium. MVD was higher in hyperplasias and carcinomas than in normal endometrium (p < 0.001. Conclusion: HIF-1α and its downstream genes are increasingly expressed from normal through premalignant to endometrioid adenocarcinoma of the endometrium, paralleled by activation of its downstream genes and increased angiogenesis. This underlines the potential importance of hypoxia and its key regulator HIF-1α in endometrial carcinogenesis.

  12. Macrophage-mediated response to hypoxia in disease

    Directory of Open Access Journals (Sweden)

    Tazzyman S

    2014-11-01

    Full Text Available Simon Tazzyman,1 Craig Murdoch,2 James Yeomans,1 Jack Harrison,1 Munitta Muthana3 1Department of Oncology, 2School of Clinical Dentistry, 3Department of Infection and Immunity, University of Sheffield, Sheffield, UK Abstract: Hypoxia plays a critical role in the pathobiology of various inflamed, diseased tissues, including malignant tumors, atherosclerotic plaques, myocardial infarcts, the synovia of rheumatoid arthritic joints, healing wounds, and sites of bacterial infection. These areas of hypoxia form when the blood supply is occluded and/or the oxygen supply is unable to keep pace with cell growth and/or infiltration of inflammatory cells. Macrophages are ubiquitous in all tissues of the body and exhibit great plasticity, allowing them to perform divergent functions, including, among others, patrolling tissue, combating invading pathogens and tumor cells, orchestrating wound healing, and restoring homeostasis after an inflammatory response. The number of tissue macrophages increases markedly with the onset and progression of many pathological states, with many macrophages accumulating in avascular and necrotic areas, where they are exposed to hypoxia. Recent studies show that these highly versatile cells then respond rapidly to the hypoxia present by altering their expression of a wide array of genes. Here we review the evidence for hypoxia-driven macrophage inflammatory responses in various disease states, and how this influences disease progression and treatment. Keywords: macrophage, hypoxia, inflammation, cytokine

  13. Glycolysis determines dichotomous regulation of T cell subsets in hypoxia

    Science.gov (United States)

    Xu, Yang; Zhang, Ming; Savoldo, Barbara; Metelitsa, Leonid S.; Rodgers, John; Yustein, Jason T.; Neilson, Joel R.

    2016-01-01

    Hypoxia occurs in many pathological conditions, including chronic inflammation and tumors, and is considered to be an inhibitor of T cell function. However, robust T cell responses occur at many hypoxic inflammatory sites, suggesting that functions of some subsets are stimulated under low oxygen conditions. Here, we investigated how hypoxic conditions influence human T cell functions and found that, in contrast to naive and central memory T cells (TN and TCM), hypoxia enhances the proliferation, viability, and cytotoxic action of effector memory T cells (TEM). Enhanced TEM expansion in hypoxia corresponded to high hypoxia-inducible factor 1α (HIF1α) expression and glycolytic activity compared with that observed in TN and TCM. We determined that the glycolytic enzyme GAPDH negatively regulates HIF1A expression by binding to adenylate-uridylate–rich elements in the 3′-UTR region of HIF1A mRNA in glycolytically inactive TN and TCM. Conversely, active glycolysis with decreased GAPDH availability in TEM resulted in elevated HIF1α expression. Furthermore, GAPDH overexpression reduced HIF1α expression and impaired proliferation and survival of T cells in hypoxia, indicating that high glycolytic metabolism drives increases in HIF1α to enhance TEM function during hypoxia. This work demonstrates that glycolytic metabolism regulates the translation of HIF1A to determine T cell responses to hypoxia and implicates GAPDH as a potential mechanism for controlling T cell function in peripheral tissue. PMID:27294526

  14. Nonlocal Means Denoising of Self-Gated and k-Space Sorted 4-Dimensional Magnetic Resonance Imaging Using Block-Matching and 3-Dimensional Filtering: Implications for Pancreatic Tumor Registration and Segmentation.

    Science.gov (United States)

    Jin, Jun; McKenzie, Elizabeth; Fan, Zhaoyang; Tuli, Richard; Deng, Zixin; Pang, Jianing; Fraass, Benedick; Li, Debiao; Sandler, Howard; Yang, Guang; Sheng, Ke; Gou, Shuiping; Yang, Wensha

    2016-07-01

    To denoise self-gated k-space sorted 4-dimensional magnetic resonance imaging (SG-KS-4D-MRI) by applying a nonlocal means denoising filter, block-matching and 3-dimensional filtering (BM3D), to test its impact on the accuracy of 4D image deformable registration and automated tumor segmentation for pancreatic cancer patients. Nine patients with pancreatic cancer and abdominal SG-KS-4D-MRI were included in the study. Block-matching and 3D filtering was adapted to search in the axial slices/frames adjacent to the reference image patch in the spatial and temporal domains. The patches with high similarity to the reference patch were used to collectively denoise the 4D-MRI image. The pancreas tumor was manually contoured on the first end-of-exhalation phase for both the raw and the denoised 4D-MRI. B-spline deformable registration was applied to the subsequent phases for contour propagation. The consistency of tumor volume defined by the standard deviation of gross tumor volumes from 10 breathing phases (σ_GTV), tumor motion trajectories in 3 cardinal motion planes, 4D-MRI imaging noise, and image contrast-to-noise ratio were compared between the raw and denoised groups. Block-matching and 3D filtering visually and quantitatively reduced image noise by 52% and improved image contrast-to-noise ratio by 56%, without compromising soft tissue edge definitions. Automatic tumor segmentation is statistically more consistent on the denoised 4D-MRI (σ_GTV = 0.6 cm(3)) than on the raw 4D-MRI (σ_GTV = 0.8 cm(3)). Tumor end-of-exhalation location is also more reproducible on the denoised 4D-MRI than on the raw 4D-MRI in all 3 cardinal motion planes. Block-matching and 3D filtering can significantly reduce random image noise while maintaining structural features in the SG-KS-4D-MRI datasets. In this study of pancreatic tumor segmentation, automatic segmentation of GTV in the registered image sets is shown to be more consistent on the denoised 4D-MRI than on the raw 4D

  15. Expression of DDX3 is directly modulated by hypoxia inducible factor-1 alpha in breast epithelial cells.

    Directory of Open Access Journals (Sweden)

    Mahendran Botlagunta

    2011-03-01

    Full Text Available DEAD box protein, DDX3, is aberrantly expressed in breast cancer cells ranging from weakly invasive to aggressive phenotypes and functions as an important regulator of cancer cell growth and survival. Here, we demonstrate that hypoxia inducible factor-1α is a transcriptional activator of DDX3 in breast cancer cells. Within the promoter region of the human DDX3 gene, we identified three putative hypoxia inducible factor-1 responsive elements. By luciferase reporter assays in combination with mutated hypoxia inducible factor-1 responsive elements, we determined that the hypoxia inducible factor-1 responsive element at position -153 relative to the translation start site is essential for transcriptional activation of DDX3 under hypoxic conditions. We also demonstrated that hypoxia inducible factor-1 binds to the DDX3 promoter and that the binding is specific, as revealed by siRNA against hypoxia inducible factor-1 and chromatin immunoprecipitation assays. Thus, the activation of DDX3 expression during hypoxia is due to the direct binding of hypoxia inducible factor-1 to hypoxia responsive elements in the DDX3 promoter. In addition, we observed a significant overlap in the protein expression pattern of hypoxia inducible factor-1α and DDX3 in MDA-MB-231 xenograft tumors. Taken together, our results demonstrate, for the first time, the role of DDX3 as a hypoxia-inducible gene that exhibits enhanced expression through the interaction of hypoxia inducible factor-1 with hypoxia inducible factor-1 responsive elements in its promoter region.

  16. Potential role of hypoxia imaging using 18F-FAZA PET to guide hypoxia-driven interventions (carbogen breathing or dose escalation) in radiation therapy

    International Nuclear Information System (INIS)

    Tran, Ly-Binh-An; Bol, Anne; Labar, Daniel; Karroum, Oussama; Bol, Vanesa; Jordan, Bénédicte; Grégoire, Vincent; Gallez, Bernard

    2014-01-01

    Background and purpose: Hypoxia-driven intervention (oxygen manipulation or dose escalation) could overcome radiation resistance linked to tumor hypoxia. Here, we evaluated the value of hypoxia imaging using 18 F-FAZA PET to predict the outcome and guide hypoxia-driven interventions. Material and methods: Two hypoxic rat tumor models were used: rhabdomyosarcoma and 9L-glioma. For the irradiated groups, the animals were divided into two subgroups: breathing either room air or carbogen. 18 F-FAZA PET images were obtained just before the irradiation to monitor the hypoxic level of each tumor. Absolute pO 2 were also measured using EPR oximetry. Dose escalation was used in Rhabdomyosarcomas. Results: For 9L-gliomas, a significant correlation between 18 F-FAZA T/B ratio and tumor growth delay was found; additionally, carbogen breathing dramatically improved the tumor response to irradiation. On the contrary, Rhabdomyosarcomas were less responsive to hyperoxic challenge. For that model, an increase in growth delay was observed using dose escalation, but not when combining irradiation with carbogen. Conclusions: 18 F-FAZA uptake may be prognostic of outcome following radiotherapy and could assess the response of tumor to carbogen breathing. 18 F-FAZA PET may help to guide the hypoxia-driven intervention with irradiation: carbogen breathing in responsive tumors or dose escalation in tumors non-responsive to carbogen

  17. Nrf2-AKT interactions regulate heme oxygenase 1 expression in kidney epithelia during hypoxia and hypoxia-reoxygenation.

    Science.gov (United States)

    Potteti, Haranatha R; Tamatam, Chandramohan R; Marreddy, Rakesh; Reddy, Narsa M; Noel, Sanjeev; Rabb, Hamid; Reddy, Sekhar P

    2016-11-01

    Ischemia-reperfusion (IR)-induced kidney injury is a major clinical problem, but its underlying mechanisms remain unclear. The transcription factor known as nuclear factor, erythroid 2-like 2 (NFE2L2 or Nrf2) is crucial for protection against oxidative stress generated by pro-oxidant insults. We have previously shown that Nrf2 deficiency enhances susceptibility to IR-induced kidney injury in mice and that its upregulation is protective. Here, we examined Nrf2 target antioxidant gene expression and the mechanisms of its activation in both human and murine kidney epithelia following acute (2 h) and chronic (12 h) hypoxia and reoxygenation conditions. We found that acute hypoxia modestly stimulates and chronic hypoxia strongly stimulates Nrf2 putative target HMOX1 expression, but not that of other antioxidant genes. Inhibition of AKT1/2 or ERK1/2 signaling blocked this induction; AKT1/2 but not ERK1/2 inhibition affected Nrf2 levels in basal and acute hypoxia-reoxygenation states. Unexpectedly, chromatin immunoprecipitation assays revealed reduced levels of Nrf2 binding at the distal AB1 and SX2 enhancers and proximal promoter of HMOX1 in acute hypoxia, accompanied by diminished levels of nuclear Nrf2. In contrast, Nrf2 binding at the AB1 and SX2 enhancers significantly but differentially increased during chronic hypoxia and reoxygenation, with reaccumulation of nuclear Nrf2 levels. Small interfering-RNA-mediated Nrf2 depletion attenuated acute and chronic hypoxia-inducible HMOX1 expression, and primary Nrf2-null kidney epithelia showed reduced levels of HMOX1 induction in response to both acute and chronic hypoxia. Collectively, our data demonstrate that Nrf2 upregulates HMOX1 expression in kidney epithelia through a distinct mechanism during acute and chronic hypoxia reoxygenation, and that both AKT1/2 and ERK1/2 signaling are required for this process. Copyright © 2016 the American Physiological Society.

  18. Hypoxia Induces Autophagy through Translational Up-Regulation of Lysosomal Proteins in Human Colon Cancer Cells.

    Directory of Open Access Journals (Sweden)

    Ming-Chih Lai

    Full Text Available Hypoxia occurs in a wide variety of physiological and pathological conditions, including tumorigenesis. Tumor cells have to adapt to hypoxia by altering their gene expression and protein synthesis. Here, we showed that hypoxia inhibits translation through activation of PERK and inactivation of mTOR in human colon cancer HCT116 cells. Prolonged hypoxia (1% O2, 16 h dramatically inhibits general translation in HCT116 cells, yet selected mRNAs remain efficiently translated under such a condition. Using microarray analysis of polysome- associated mRNAs, we identified a large number of hypoxia-regulated genes at the translational level. Efficiently translated mRNAs during hypoxia were validated by polysome profiling and quantitative real-time RT-PCR. Pathway enrichment analysis showed that many of the up-regulated genes are involved in lysosome, glycan and lipid metabolism, antigen presentation, cell adhesion, and remodeling of the extracellular matrix and cytoskeleton. The majority of down-regulated genes are involved in apoptosis, ubiquitin-mediated proteolysis, and oxidative phosphorylation. Further investigation showed that hypoxia induces lysosomal autophagy and mitochondrial dysfunction through translational regulation in HCT116 cells. The abundance of several translation factors and the mTOR kinase activity are involved in hypoxia-induced mitochondrial autophagy in HCT116 cells. Our studies highlight the importance of translational regulation for tumor cell adaptation to hypoxia.

  19. Monitoring hypoxia and vasculature during bevacizumab treatment in a murine colorectal cancer model

    NARCIS (Netherlands)

    Heijmen, L.; ter Voert, E. G. W.; Punt, C. J. A.; Heerschap, A.; Oyen, W. J. G.; Bussink, J.; Sweep, C. G. J.; Laverman, P.; Span, P. N.; de Geus-Oei, L. F.; Boerman, O. C.; van Laarhoven, H. W. M.

    2014-01-01

    The purpose of this study was to assess the effect of bevacizumab on vasculature and hypoxia in a colorectal tumor model. Nude mice with subcutaneous LS174T tumors were treated with bevacizumab or saline. To assess tumor properties, separate groups of mice were imaged using (18) F-Fluoromisonidazole

  20. Hypoxia-inducible factors and sphingosine 1-phosphate signaling.

    Science.gov (United States)

    Cuvillier, Olivier; Ader, Isabelle

    2011-11-01

    Hypoxia, defined as reduced tissue oxygen concentration, is a characteristic of solid tumors and is an indicator of unfavorable diagnosis in patients. At the cellular level, the adaptation to hypoxia is under the control of two related transcription factors, HIF-1α and HIF-2α (Hypoxia-Inducible Factor), which activate expression of genes promoting angiogenesis, metastasis, increased tumor growth and resistance to treatments. A role for HIF-1α and HIF-2α is also emerging in hematologic malignancies such as lymphoma and l eukemia. Recent studies have identified the sphingosine kinase 1/sphingosine 1-phosphate (SphK1/S1P) signaling pathway - which elicits various cellular processes including cell proliferation, cell survival or angiogenesis - as a new regulator of HIF-1α or HIF-2α activity. This review will consider how targeting the SphK1/S1P signaling could represent an attractive strategy for therapeutic intervention in cancer.

  1. Modification of photodynamic therapy-induced hypoxia by Fluosol-DA 20%

    International Nuclear Information System (INIS)

    Henderson, B.W.; Fingar, V.H.

    1987-01-01

    Photodynamic therapy (PDT) employs the activation of tumor-localizing porphyrins by light, resulting in the formation of cytotoxic singlet oxygen, and subsequent tumor destruction. The implications of tumor oxygenation on PDT have been studied since the effects of PDT appear to be oxygen limited. Tumor hypoxia may be the primary mechanism of tumor damage, or may facilitate the expression of tumor cell damage. Alternatively, tumor cell damage may be limited by tumor hypoxia induced by PDT. This study examined the modification in PDT-induced tumor hypoxia by Fluosol-DA 20% and carbogen breathing. C/sub 3/H mice bearing RIF tumors were given 10 mg/kg photosensitizer (Photofrin II) 24 hr prior to PDT treatment. One hr before treatment, mice were given intracardiac injections of either 12 ml/kg Fluosol-DA 20%, or saline (controls). Mice were placed in airtight, carbogen flushed chambers and tumors were exposed to 135 J/cm/sup 2/ of 630 nm light. The hypoxic fraction of PDT-treated tumors was assessed by a radiobioloigcal assay in which cell survival of these tumors to radiation was compared to survival of fully oxygenated, and completely hypoxic tumors, thereby allowing calculation of the hypoxic fraction. Fluosol-DA was shown to reduce the hypoxic fraction of tumors given PDT when compared to controls. However, no changes in long-term tumor control were observed. Further implications of these findings are discussed

  2. Nitric oxide interferes with hypoxia signaling during colonic inflammation.

    Science.gov (United States)

    Caria, Cintia Rabelo e Paiva; Moscato, Camila Henrique; Tomé, Renata Bortolin Guerra; Pedrazzoli, José; Ribeiro, Marcelo Lima; Gambero, Alessandra

    2014-01-01

    Intestinal inflammation can induce a local reduction in oxygen levels that triggers an adaptive response centered on the expression of hypoxia-inducible factors (HIFs). Nitric oxide, a well-described inflammatory mediator, may interfere with hypoxia signaling. We aimed to evaluate the role of nitric oxide in hypoxia signaling during colonic inflammation. Colitis was induced by single (acute) or repeated (reactivated colitis) trinitrobenzenosulfonic acid administration in rats. In addition, one group of rats with reactivated colitis was also treated with Nw-Nitro-L-arginine methyl ester hydrochloride to block nitric oxide synthase. Colitis was assessed by macroscopic score and myeloperoxidase activity in the colon samples. Hypoxia was determined using the oxygen-dependent probe, pimonidazole. The expression of HIF-1α and HIF-induced factors (vascular endothelial growth factor - VEGF and apelin) was assessed using Western blotting. The single or repeated administration of trinitrobenzenosulfonic acid to rats induced colitis which was characterized by a high macroscopic score and myeloperoxidase activity. Hypoxia was observed with both protocols. During acute colitis, HIF-1α expression was not increased, but VEGF and apelin were increased. HIF-1α expression was inhibited during reactivated colitis, and VEGF and apelin were not increased. Nw-Nitro-L-arginine methyl ester hydrochloride blockade during reactivated colitis restored HIF-1α, VEGF and apelin expression. Nitric oxide could interfere with hypoxia signaling during reactivated colitis inflammation modifying the expression of proteins regulated by HIF-1α.

  3. NITRIC OXIDE INTERFERES WITH HYPOXIA SIGNALING DURING COLONIC INFLAMMATION

    Directory of Open Access Journals (Sweden)

    Cintia Rabelo e Paiva CARIA

    2014-12-01

    Full Text Available Context Intestinal inflammation can induce a local reduction in oxygen levels that triggers an adaptive response centered on the expression of hypoxia-inducible factors (HIFs. Nitric oxide, a well-described inflammatory mediator, may interfere with hypoxia signaling. Objectives We aimed to evaluate the role of nitric oxide in hypoxia signaling during colonic inflammation. Methods Colitis was induced by single (acute or repeated (reactivated colitis trinitrobenzenosulfonic acid administration in rats. In addition, one group of rats with reactivated colitis was also treated with Nw-Nitro-L-arginine methyl ester hydrochloride to block nitric oxide synthase. Colitis was assessed by macroscopic score and myeloperoxidase activity in the colon samples. Hypoxia was determined using the oxygen-dependent probe, pimonidazole. The expression of HIF-1α and HIF-induced factors (vascular endothelial growth factor - VEGF and apelin was assessed using Western blotting. Results The single or repeated administration of trinitrobenzenosulfonic acid to rats induced colitis which was characterized by a high macroscopic score and myeloperoxidase activity. Hypoxia was observed with both protocols. During acute colitis, HIF-1α expression was not increased, but VEGF and apelin were increased. HIF-1α expression was inhibited during reactivated colitis, and VEGF and apelin were not increased. Nw-Nitro-L-arginine methyl ester hydrochloride blockade during reactivated colitis restored HIF-1α, VEGF and apelin expression. Conclusions Nitric oxide could interfere with hypoxia signaling during reactivated colitis inflammation modifying the expression of proteins regulated by HIF-1α.

  4. Imaging probe for tumor malignancy

    Science.gov (United States)

    Tanaka, Shotaro; Kizaka-Kondoh, Shinae; Hiraoka, Hasahiro

    2009-02-01

    Solid tumors possess unique microenvironments that are exposed to chronic hypoxic conditions ("tumor hypoxia"). Although more than half a century has passed since it was suggested that tumor hypoxia correlated with poor treatment outcomes and contributed to cancer recurrence, a fundamental solution to this problem has yet to be found. Hypoxia-inducible factor (HIF-1) is the main transcription factor that regulates the cellular response to hypoxia. It induces various genes whose functions are strongly associated with malignant alteration of the entire tumor. The cellular changes induced by HIF-1 are extremely important targets of cancer therapy, particularly in therapy against refractory cancers. Imaging of the HIF-1-active microenvironment is therefore important for cancer therapy. To image HIF-1activity in vivo, we developed a PTD-ODD fusion protein, POHA, which was uniquely labeled with near-infrared fluorescent dye at the C-terminal. POHA has two functional domains: protein transduction domain (PTD) and VHL-mediated protein destruction motif in oxygen-dependent degradation (ODD) domain of the alpha subunit of HIF-1 (HIF-1α). It can therefore be delivered to the entire body and remain stabilized in the HIF-1-active cells. When it was intravenously injected into tumor-bearing mice, a tumor-specific fluorescence signal was detected in the tumor 6 h after the injection. These results suggest that POHA can be used an imaging probe for tumor malignancy.

  5. Hypoxia-inducible factor-1α induces multidrug resistance protein in colon cancer

    Directory of Open Access Journals (Sweden)

    Lv Y

    2015-07-01

    Full Text Available Yingqian Lv, Shan Zhao, Jinzhu Han, Likang Zheng, Zixin Yang, Li Zhao Department of Oncology, The Second Hospital, Hebei Medical University, Shijiazhuang, Hebei Province, People’s Republic of China Abstract: Multidrug resistance is the major cause of chemotherapy failure in many solid tumors, including colon cancer. Hypoxic environment is a feature for all solid tumors and is important for the development of tumor resistance to chemotherapy. Hypoxia-inducible factor (HIF-1α is the key transcription factor that mediates cellular response to hypoxia. HIF-1α has been shown to play an important role in tumor resistance; however, the mechanism is still not fully understood. Here, we found that HIF-1α and the drug resistance-associated gene multidrug resistance associated protein 1 (MRP1 were induced by treatment of colon cancer cells with the hypoxia-mimetic agent cobalt chloride. Inhibition of HIF-1α by RNA interference and dominant-negative protein can significantly reduce the induction of MRP1 by hypoxia. Bioinformatics analysis showed that a hypoxia response element is located at -378 to -373 bp upstream of the transcription start site of MRP1 gene. Luciferase reporter assay combined with mutation analysis confirmed that this element is essential for hypoxia-mediated activation of MRP gene. Furthermore, RNA interference revealed that HIF-1α is necessary for this hypoxia-driven activation of MRP1 promoter. Importantly, chromatin immunoprecipitation analysis demonstrated that HIF-1α could directly bind to this HRE site in vivo. Together, these data suggest that MRP1 is a downstream target gene of HIF-1α, which provides a potential novel mechanism for HIF-1α-mediated drug resistance in colon cancer and maybe other solid tumors as well. Keywords: hypoxia, hypoxia-inducible factor-1α, multidrug resistance associated protein, transcriptional regulation, chemotherapy tolerance

  6. Magnetic nanoparticle drug delivery systems for targeting tumor

    Science.gov (United States)

    Mody, Vicky V.; Cox, Arthur; Shah, Samit; Singh, Ajay; Bevins, Wesley; Parihar, Harish

    2014-04-01

    Tumor hypoxia, or low oxygen concentration, is a result of disordered vasculature that lead to distinctive hypoxic microenvironments not found in normal tissues. Many traditional anti-cancer agents are not able to penetrate into these hypoxic zones, whereas, conventional cancer therapies that work by blocking cell division are not effective to treat tumors within hypoxic zones. Under these circumstances the use of magnetic nanoparticles as a drug delivering agent system under the influence of external magnetic field has received much attention, based on their simplicity, ease of preparation, and ability to tailor their properties for specific biological applications. Hence in this review article we have reviewed current magnetic drug delivery systems, along with their application and clinical status in the field of magnetic drug delivery.

  7. Glycogen synthesis is induced in hypoxia by the hypoxia-inducible factor and promotes cancer cell survival

    Directory of Open Access Journals (Sweden)

    Joffrey ePelletier

    2012-02-01

    Full Text Available The hypoxia-inducible factor 1 (HIF-1, in addition to genetic and epigenetic changes, is largely responsible for alterations in cell metabolism in hypoxic tumor cells. This transcription factor not only favors cell proliferation through the metabolic shift from oxidative phosphorylation to glycolysis and lactic acid production but also stimulates nutrient supply by mediating adaptive survival mechanisms. In this study we showed that glycogen synthesis is enhanced in non-cancer and cancer cells when exposed to hypoxia, resulting in a large increase in glycogen stores. Furthermore, we demonstrated that the mRNA and protein levels of the first enzyme of glycogenesis, phosphoglucomutase1 (PGM1, were increased in hypoxia. We showed that induction of glycogen storage as well as PGM1 expression were dependent on HIF-1 and HIF-2. We established that hypoxia-induced glycogen stores are rapidly mobilized in cells that are starved of glucose. Glycogenolysis allows these hypoxia-preconditioned cells to confront and survive glucose deprivation. In contrast normoxic control cells exhibit a high rate of cell death following glucose removal. These findings point to the important role of hypoxia and HIF in inducing mechanisms of rapid adaptation and survival in response to a decrease in oxygen tension. We propose that a decrease in pO2 acts as an alarm that prepares the cells to face subsequent nutrient depletion and to survive.

  8. Interplay between sirtuins, MYC and hypoxia-inducible factor in cancer-associated metabolic reprogramming

    Directory of Open Access Journals (Sweden)

    Bernadette M. M. Zwaans

    2014-09-01

    Full Text Available In the early twentieth century, Otto Heinrich Warburg described an elevated rate of glycolysis occurring in cancer cells, even in the presence of atmospheric oxygen (the Warburg effect. Despite the inefficiency of ATP generation through glycolysis, the breakdown of glucose into lactate provides cancer cells with a number of advantages, including the ability to withstand fluctuations in oxygen levels, and the production of intermediates that serve as building blocks to support rapid proliferation. Recent evidence from many cancer types supports the notion that pervasive metabolic reprogramming in cancer and stromal cells is a crucial feature of neoplastic transformation. Two key transcription factors that play major roles in this metabolic reprogramming are hypoxia inducible factor-1 (HIF1 and MYC. Sirtuin-family deacetylases regulate diverse biological processes, including many aspects of tumor biology. Recently, the sirtuin SIRT6 has been shown to inhibit the transcriptional output of both HIF1 and MYC, and to function as a tumor suppressor. In this Review, we highlight the importance of HIF1 and MYC in regulating tumor metabolism and their regulation by sirtuins, with a main focus on SIRT6.

  9. Interplay between sirtuins, MYC and hypoxia-inducible factor in cancer-associated metabolic reprogramming.

    Science.gov (United States)

    Zwaans, Bernadette M M; Lombard, David B

    2014-09-01

    In the early twentieth century, Otto Heinrich Warburg described an elevated rate of glycolysis occurring in cancer cells, even in the presence of atmospheric oxygen (the Warburg effect). Despite the inefficiency of ATP generation through glycolysis, the breakdown of glucose into lactate provides cancer cells with a number of advantages, including the ability to withstand fluctuations in oxygen levels, and the production of intermediates that serve as building blocks to support rapid proliferation. Recent evidence from many cancer types supports the notion that pervasive metabolic reprogramming in cancer and stromal cells is a crucial feature of neoplastic transformation. Two key transcription factors that play major roles in this metabolic reprogramming are hypoxia inducible factor-1 (HIF1) and MYC. Sirtuin-family deacetylases regulate diverse biological processes, including many aspects of tumor biology. Recently, the sirtuin SIRT6 has been shown to inhibit the transcriptional output of both HIF1 and MYC, and to function as a tumor suppressor. In this Review, we highlight the importance of HIF1 and MYC in regulating tumor metabolism and their regulation by sirtuins, with a main focus on SIRT6. © 2014. Published by The Company of Biologists Ltd.

  10. PKA activity exacerbates hypoxia-induced ROS formation and hypoxic injury in PC-12 cells.

    Science.gov (United States)

    Gozal, Evelyne; Metz, Cynthia J; Dematteis, Maurice; Sachleben, Leroy R; Schurr, Avital; Rane, Madhavi J

    2017-09-05

    Hypoxia is a primary factor in many pathological conditions. Hypoxic cell death is commonly attributed to metabolic failure and oxidative injury. cAMP-dependent protein kinase A (PKA) is activated in hypoxia and regulates multiple enzymes of the mitochondrial electron transport chain, thus may be implicated in cellular energy depletion and hypoxia-induced cell death. Wild type (WT) PC-12 cells and PKA activity-deficient 123.7 PC-12 cells were exposed to 3, 6, 12 and 24h hypoxia (0.1% or 5% O 2 ). Hypoxia, at 24h 0.1% O 2 , induced cell death and increased reactive oxygen species (ROS) in WT PC-12 cells. Despite lower ATP levels in normoxic 123.7 cells than in WT cells, hypoxia only decreased ATP levels in WT cells. However, menadione-induced oxidative stress similarly affected both cell types. While mitochondrial COX IV expression remained consistently higher in 123.7 cells, hypoxia decreased COX IV expression in both cell types. N-acetyl cysteine antioxidant treatment blocked hypoxia-induced WT cell death without preventing ATP depletion. Transient PKA catα expression in 123.7 cells partially restored hypoxia-induced ROS but did not alter ATP levels or COX IV expression. We conclude that PKA signaling contributes to hypoxic injury, by regulating oxidative stress rather than by depleting ATP levels. Therapeutic strategies targeting PKA signaling may improve cellular adaptation and recovery in hypoxic pathologies. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. HIF-1 and NDRG2 contribute to hypoxia-induced radioresistance of cervical cancer Hela cells

    International Nuclear Information System (INIS)

    Liu, Junye; Zhang, Jing; Wang, Xiaowu; Li, Yan; Chen, Yongbin; Li, Kangchu; Zhang, Jian; Yao, Libo; Guo, Guozhen

    2010-01-01

    Hypoxia inducible factor 1 (HIF-1), the key mediator of hypoxia signaling pathways, has been shown involved in hypoxia-induced radioresistance. However, the underlying mechanisms are unclear. The present study demonstrated that both hypoxia and hypoxia mimetic cobalt chloride could increase the radioresistance of human cervical cancer Hela cells. Meanwhile, ectopic expression of HIF-1 could enhance the resistance of Hela cells to radiation, whereas knocking-down of HIF-1 could increase the sensitivity of Hela cells to radiation in the presence of hypoxia. N-Myc downstream-regulated gene 2 (NDRG2), a new HIF-1 target gene identified in our lab, was found to be upregulated by hypoxia and radiation in a HIF-1-dependent manner. Overexpression of NDRG2 resulted in decreased sensitivity of Hela cells to radiation while silencing NDRG2 led to radiosensitization. Moreover, NDRG2 was proved to protect Hela cells from radiation-induced apoptosis and abolish radiation-induced upregulation of Bax. Taken together, these data suggest that both HIF-1 and NDRG2 contribute to hypoxia-induced tumor radioresistance and that NDRG2 acts downstream of HIF-1 to promote radioresistance through suppressing radiation-induced Bax expression. It would be meaningful to further explore the clinical application potential of HIF-1 and NDRG2 blockade as radiosensitizer for tumor therapy.

  12. Hypoxia affects cellular responses to plant extracts.

    Science.gov (United States)

    Liew, Sien-Yei; Stanbridge, Eric J; Yusoff, Khatijah; Shafee, Norazizah

    2012-11-21

    inhibition. Hypoxia variably alters the cytotoxic effects of TCM plant extracts on cancer cells. Carica papaya showed enhanced cytotoxic effect on hypoxic cancer cells by inhibiting HIF activities. These findings provide a plausible approach to killing hypoxic cancer cells in solid tumors. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  13. ATR controls cellular adaptation to hypoxia through positive regulation of hypoxia-inducible factor 1 (HIF-1) expression.

    Science.gov (United States)

    Fallone, F; Britton, S; Nieto, L; Salles, B; Muller, C

    2013-09-12

    Tumor cells adaptation to severe oxygen deprivation (hypoxia) plays a major role in tumor progression. The transcription factor HIF-1 (hypoxia-inducible factor 1), whose α-subunit is stabilized under hypoxic conditions is a key component of this process. Recent studies showed that two members of the phosphoinositide 3-kinase-related kinases (PIKKs) family, ATM (ataxia telangiectasia mutated) and DNA-PK (DNA-dependent protein kinase), regulate the hypoxic-dependent accumulation of HIF-1. These proteins initiate cellular stress responses when DNA damage occurs. In addition, it has been demonstrated that extreme hypoxia induces a replicative stress resulting in regions of single-stranded DNA at stalled replication forks and the activation of ATR (ataxia telangiectasia and Rad3 related protein), another member of the PIKKs family. Here, we show that even less severe hypoxia (0.1% O2) also induces activation of ATR through replicative stress. Importantly, in using either transiently silenced ATR cells, cells expressing an inactive form of ATR or cells exposed to an ATR inhibitor (CGK733), we demonstrate that hypoxic ATR activation positively regulates the key transcription factor HIF-1 independently of the checkpoint kinase Chk1. We show that ATR kinase activity regulates HIF-1α at the translational level and we find that the elements necessary for the regulation of HIF-1α translation are located within the coding region of HIF-1α mRNA. Finally, by using three independent cellular models, we clearly show that the loss of ATR expression and/or kinase activity results in the decrease of HIF-1 DNA binding under hypoxia and consequently affects protein expression levels of two HIF-1 target genes, GLUT-1 and CAIX. Taken together, our data show a new function for ATR in cellular adaptation to hypoxia through regulation of HIF-1α translation. Our work offers new prospect for cancer therapy using ATR inhibitors with the potential to decrease cellular adaptation in hypoxic

  14. Vasculogenic mimicry and tumor metastasis.

    Science.gov (United States)

    Zhang, Jingxin; Qiao, Lili; Liang, Ning; Xie, Jian; Luo, Hui; Deng, Guodong; Zhang, Jiandong

    2016-01-01

    Vasculogenic mimicry (VM), a microvascular channel made up of nonendothelial cells, has been accepted as a new model of neovascularization in aggressive tumors, owning to the specific capacity of malignant cells to form vessel-like networks which provide sufficient blood supply for tumor growth. Multiple molecular mechanisms, especially vascular endothelial (VE)-cadherin, erythropoietin-producing hepatocellular receptor A2 (EphA2), phosphatidyl inositol 3-kinase (PI3K), matrix metalloproteinases (MMPs), vascular endothelial growth factor receptor (VEGFR1), and hypoxia inducible factor (HIF)-1a, have been reported to participate in VM formation which is associated with tumor migration and invasion. In addition, hypoxia, cancer stem cells (CSCs) and epithelial-mesenehymal transition (EMT) are regarded as significant factors in VM formation and tumor metastasis. Due to the important effects of VM on tumor progression, a review was carried out in the present study, to synthetically analyze the relationship between VM and tumor metastasis.

  15. RNA Sequencing Reveals that Kaposi Sarcoma-Associated Herpesvirus Infection Mimics Hypoxia Gene Expression Signature

    Science.gov (United States)

    Viollet, Coralie; Davis, David A.; Tekeste, Shewit S.; Reczko, Martin; Pezzella, Francesco; Ragoussis, Jiannis

    2017-01-01

    Kaposi sarcoma-associated herpesvirus (KSHV) causes several tumors and hyperproliferative disorders. Hypoxia and hypoxia-inducible factors (HIFs) activate latent and lytic KSHV genes, and several KSHV proteins increase the cellular levels of HIF. Here, we used RNA sequencing, qRT-PCR, Taqman assays, and pathway analysis to explore the miRNA and mRNA response of uninfected and KSHV-infected cells to hypoxia, to compare this with the genetic changes seen in chronic latent KSHV infection, and to explore the degree to which hypoxia and KSHV infection interact in modulating mRNA and miRNA expression. We found that the gene expression signatures for KSHV infection and hypoxia have a 34% overlap. Moreover, there were considerable similarities between the genes up-regulated by hypoxia in uninfected (SLK) and in KSHV-infected (SLKK) cells. hsa-miR-210, a HIF-target known to have pro-angiogenic and anti-apoptotic properties, was significantly up-regulated by both KSHV infection and hypoxia using Taqman assays. Interestingly, expression of KSHV-encoded miRNAs was not affected by hypoxia. These results demonstrate that KSHV harnesses a part of the hypoxic cellular response and that a substantial portion of hypoxia-induced changes in cellular gene expression are induced by KSHV infection. Therefore, targeting hypoxic pathways may be a useful way to develop therapeutic strategies for KSHV-related diseases. PMID:28046107

  16. Hypoxia and the Presence of Human Vascular Endothelial Cells Affect Prostate Cancer Cell Invasion and Metabolism

    Directory of Open Access Journals (Sweden)

    Ellen Ackerstaff

    2007-12-01

    Full Text Available Tumor progression and metastasis are influenced by hypoxia, as well as by interactions between cancer cells and components of the stroma, such as endothelial cells. Here, we have used a magnetic resonance (MRcompatible invasion assay to further understand the effects of hypoxia on human prostate cancer cell invasion and metabolism in the presence and absence of human umbilical vein endothelial cells (HUVECs. Additionally, we compared endogenous activities of selected proteases related to invasion in PC-3 cells and HUVECs, profiled gene expression of PC-3 cells by microarray, evaluated cell proliferation of PC-3 cells and HUVECs by flow cytometry, under hypoxic and oxygenated conditions. The invasion of less-invasive DU-145 cells was not affected by either hypoxia or the presence of HUVECs. However, hypoxia significantly decreased the invasion of PC-3 cells. This hypoxia-induced decrease was attenuated by the presence of HUVECs, whereas under oxygenated conditions, HUVECs did not alter the invasion of PC-3 cells. Cell metabolism changed distinctly with hypoxia and invasion. The endogenous activity of selected extracellular proteases, although altered by hypoxia, did not fully explain the hypoxia-induced changes in invasion. Gene expression profiling indicated that hypoxia affects multiple cellular functions and pathways.

  17. Tumor suppressor PDCD4 modulates miR-184-mediated direct suppression of C-MYC and BCL2 blocking cell growth and survival in nasopharyngeal carcinoma.

    Science.gov (United States)

    Zhen, Yan; Liu, Zhen; Yang, Huiling; Yu, Xiaoli; Wu, Qiangyun; Hua, Shengni; Long, Xiaobin; Jiang, Qingping; Song, Ye; Cheng, Chao; Wang, Hao; Zhao, Menyang; Fu, Qiaofen; Lyu, Xiaoming; Chen, Yiyu; Fan, Yue; Liu, Yan; Li, Xin; Fang, Weiyi

    2013-10-24

    Programmed cell death 4 (PDCD4), a novel tumor suppressor, inhibits cell proliferation, migration and invasion as well as promotes cell apoptosis in tumors. However, the molecular mechanism of its tumor-suppressive function remains largely unknown in tumors including nasopharyngeal carcinoma (NPC). In this study, downregulated PDCD4 expression was significantly associated with the status of NPC progression and poor prognosis. PDCD4 markedly suppressed the ability of cell proliferation and cell survival by modulating C-MYC-controlled cell cycle and BCL-2-mediated mitochondrion apoptosis resistance signals, and oncogenic transcription factor C-JUN in NPC. Furthermore, miR-184, a tumor-suppressive miRNA modulated by PDCD4 directly targeting BCL2 and C-MYC, participated in PDCD4-mediated suppression of cell proliferation and survival in NPC. Further, we found that PDCD4 decreased the binding of C-Jun to the AP-1 element on the miR-184 promoter regions by PI3K/AKT/JNK/C-Jun pathway and stimulated miR-184 expression. In clinical fresh specimens, reduced PDCD4 mRNA level was positively correlated with miR-184 expression in NPC. Our studies are the first to demonstrate that PDCD4 as tumor suppressor regulated miR-184-mediated direct targeting of BCL2 and C-MYC via PI3K/AKT and JNK/C-Jun pathway attenuating cell proliferation and survival in NPC.

  18. A Novel Strategy for Inducing the Antitumor Effects of Triterpenoid Compounds: Blocking the Protumoral Functions of Tumor-Associated Macrophages via STAT3 Inhibition

    Directory of Open Access Journals (Sweden)

    Yukio Fujiwara

    2014-01-01

    Full Text Available There are many types of nontumor cells, including leukocytes, fibroblasts, and endothelial cells, in the tumor microenvironment. Among these cells, infiltrating macrophages have recently received attention as novel target cells due to their protumoral functions. Infiltrating macrophages are called tumor-associated macrophages (TAMs. TAMs polarized to the M2 phenotype are involved in tumor development and are associated with a poor clinical prognosis. Therefore, the regulation of TAM activation or M2 polarization is a new strategy for antitumor therapy. We screened natural compounds possessing an inhibitory effect on the M2 polarization of human macrophages. Among 200 purified natural compounds examined, corosolic acid (CA and oleanolic acid (OA, both are categorized in triterpenoid compounds, inhibited macrophage polarization to M2 phenotype by suppressing STAT3 activation. CA and OA also directly inhibited tumor cell proliferation and sensitized tumor cells to anticancer drugs, such as adriamycin and cisplatin. The in vivo experiments showed that CA significantly suppressed subcutaneous tumor development and lung metastasis in a murine sarcoma model. The application of triterpenoid compounds, such as CA and OA, is a potential new anticancer therapy targeting macrophage activation, with synergistic effects with anticancer agents.

  19. Intermittent hypoxia and neurorehabilitation.

    Science.gov (United States)

    Gonzalez-Rothi, Elisa J; Lee, Kun-Ze; Dale, Erica A; Reier, Paul J; Mitchell, Gordon S; Fuller, David D

    2015-12-15

    In recent years, it has become clear that brief, repeated presentations of hypoxia [i.e., acute intermittent hypoxia (AIH)] can boost the efficacy of more traditional therapeutic strategies in certain cases of neurologic dysfunction. This hypothesis derives from a series of studies in animal models and human subjects performed over the past 35 yr. In 1980, Millhorn et al. (Millhorn DE, Eldridge FL, Waldrop TG. Respir Physiol 41: 87-103, 1980) showed that electrical stimulation of carotid chemoafferent neurons produced a persistent, serotonin-dependent increase in phrenic motor output that outlasts the stimulus for more than 90 min (i.e., a "respiratory memory"). AIH elicits similar phrenic "long-term facilitation" (LTF) by a mechanism that requires cervical spinal serotonin receptor activation and de novo protein synthesis. From 2003 to present, a series of studies demonstrated that AIH can induce neuroplasticity in the injured spinal cord, causing functional recovery of breathing capacity after cervical spinal injury. Subsequently, it was demonstrated that repeated AIH (rAIH) can induce recovery of limb function, and the functional benefits of rAIH are greatest when paired with task-specific training. Since uncontrolled and/or prolonged intermittent hypoxia can elicit pathophysiology, a challenge of intermittent hypoxia research is to ensure that therapeutic protocols are well below the threshold for pathogenesis. This is possible since many low dose rAIH protocols have induced functional benefits without evidence of pathology. We propose that carefully controlled rAIH is a safe and noninvasive modality that can be paired with other neurorehabilitative strategies including traditional activity-based physical therapy or cell-based therapies such as intraspinal transplantation of neural progenitors. Copyright © 2015 the American Physiological Society.

  20. Hypoxia and Fetal Heart Development

    OpenAIRE

    Patterson, A.J.; Zhang, L

    2010-01-01

    Fetal hearts show a remarkable ability to develop under hypoxic conditions. The metabolic flexibility of fetal hearts allows sustained development under low oxygen conditions. In fact, hypoxia is critical for proper myocardial formation. Particularly, hypoxia inducible factor 1 (HIF-1) and vascular endothelial growth factor play central roles in hypoxia-dependent signaling in fetal heart formation, impacting embryonic outflow track remodeling and coronary vessel growth. Although HIF is not th...

  1. Effectiveness and biological effects of techniques used to induce hypoxia in solid tumours

    International Nuclear Information System (INIS)

    Rockwell, S.; Martin, D.F.

    1986-01-01

    Acute hypoxia is often induced in rodent tumors during studies of the oxygenation or the therapeutic responses of the tumors. Analyses of data from such experiments generally assume that these processes have no effects. The studies described in this report test several aspects of these assumptions using BA1112 rat rhabdomyosarcomas and EMT6 mouse mammary tumors. Both clamping and asphyxiation appear to be effective in producing hypoxia in the tumors. Induction of artificial hypoxia for the times necessary for irradiation was not toxic to the tumor cells and generally did not alter the growth of unirradiated tumors. Clamping BA1112 tumors for 30 min and removing the clamp just before irradiation altered the tumor cell survival curve and the TCD 50 . Furthermore, anesthesia and/or restraint (necessary during clamping) have significant effects on tumours and hosts. The data show that the assumptions underlying the use of clamping and N 2 -asphyxiation to produce hypoxia for short periods in vivo are generally reasonable for BA1112 and EMT6 tumors. (Auth.)

  2. Hypoxia targeted bifunctional suicide gene expression enhances radiotherapy in vitro and in vivo

    International Nuclear Information System (INIS)

    Sun, Xiaorong; Xing, Ligang; Deng, Xuelong; Hsiao, Hung Tsung; Manami, Akiko; Koutcher, Jason A.; Clifton Ling, C.; Li, Gloria C.

    2012-01-01

    Purpose: To investigate whether hypoxia targeted bifunctional suicide gene expression-cytosine deaminase (CD) and uracil phosphoribosyltransferase (UPRT) with 5-FC treatments can enhance radiotherapy. Materials and methods: Stable transfectants of R3327-AT cells were established which express a triple-fusion-gene: CD, UPRT and monomoric DsRed (mDsRed) controlled by a hypoxia inducible promoter. Hypoxia-induced expression/function of CDUPRTmDsRed was verified by western blot, flow cytometry, fluorescent microscopy, and cytotoxicity assay of 5-FU and 5-FC. Tumor-bearing mice were treated with 5-FC and local radiation. Tumor volume was monitored and compared with those treated with 5-FC or radiation alone. In addition, the CDUPRTmDsRed distribution in hypoxic regions of tumor sections was visualized with fluorescent microscopy. Results: Hypoxic induction of CDUPRTmDsRed protein correlated with increased sensitivity to 5-FC and 5-FU. Significant radiosensitization effects were detected after 5-FC treatments under hypoxic conditions. In the tumor xenografts, the distribution of CDUPRTmDsRed expression visualized with fluorescence microscopy was co-localized with the hypoxia marker pimonidazole positive staining cells. Furthermore, administration of 5-FC to mice in combination with local irradiation resulted in significant tumor regression, as in comparison with 5-FC or radiation treatments alone. Conclusions: Our data suggest that the hypoxia-inducible CDUPRT/5-FC gene therapy strategy has the ability to specifically target hypoxic cancer cells and significantly improve the tumor control in combination with radiotherapy.

  3. Molecular imaging using Cu-ATSM and FDG in solid canine tumors

    DEFF Research Database (Denmark)

    Hansen, Anders Elias

    Tumor hypoxia is one of the key factors in the development of aggressive and treatment resistant tumors. The negative effects of tumor hypoxia are mediated both by the direct lack of molecular oxygen for therapeutic efficacy and by pro- teomic and genomic changes induced in hypoxic tumor cells....... Identification of hypoxic tumor and intratumoral hypoxic regions therefore hold the potential to serve as a basis for individualized treatment protocols, including image guided radiation therapy. The current PhD project was undertaken to study tumor hypoxia in cancer bearing dogs, with the aims of 1) identifying...

  4. Regulation of HIF prolyl hydroxylases by hypoxia-inducible factors.

    Science.gov (United States)

    Aprelikova, Olga; Chandramouli, Gadisetti V R; Wood, Matthew; Vasselli, James R; Riss, Joseph; Maranchie, Jodi K; Linehan, W Marston; Barrett, J Carl

    2004-06-01

    Hypoxia and induction of hypoxia-inducible factors (HIF-1alpha and HIF-2alpha) is a hallmark of many tumors. Under normal oxygen tension HIF-alpha subunits are rapidly degraded through prolyl hydroxylase dependent interaction with the von Hippel-Lindau (VHL) tumor suppressor protein, a component of E3 ubuiquitin ligase complex. Using microarray analysis of VHL mutated and re-introduced cells, we found that one of the prolyl hydroxylases (PHD3) is coordinately expressed with known HIF target genes, while the other two family members (PHD1 and 2) did not respond to VHL. We further tested the regulation of these genes by HIF-1 and HIF-2 and found that siRNA targeted degradation of HIF-1alpha and HIF-2alpha results in decreased hypoxia-induced PHD3 expression. Ectopic overexpression of HIF-2alpha in two different cell lines provided a much better induction of PHD3 gene than HIF-1alpha. In contrast, we demonstrate that PHD2 is not affected by overexpression or downregulation of HIF-2alpha. However, induction of PHD2 by hypoxia has HIF-1-independent and -dependent components. Short-term hypoxia (4 h) results in induction of PHD2 independent of HIF-1, while PHD2 accumulation by prolonged hypoxia (16 h) was decreased by siRNA-mediated degradation of HIF-1alpha subunit. These data further advance our understanding of the differential role of HIF factors and putative feedback loop in HIF regulation. Copyright 2004 Wiley-Liss, Inc.

  5. Gold namoprtices enhance anti-tumor effect of radiotherapy to hypoxic tumor

    International Nuclear Information System (INIS)

    Kim, Mi Sun; Lee, Eun Jung; Kim, Jae Won; Keum, Ki Chang; Koom, Woong Sub; Chung, Ui Seok; Koh, Won Gun

    2016-01-01

    Hypoxia can impair the therapeutic efficacy of radiotherapy (RT). Therefore, a new strategy is necessary for enhancing the response to RT. In this study, we investigated whether the combination of nanoparticles and RT is effective in eliminating the radioresistance of hypoxic tumors. Gold nanoparticles (GNPs) consisting of a silica core with a gold shell were used. CT26 colon cancer mouse model was developed to study whether the combination of RT and GNPs reduced hypoxia-induced radioresistance. Hypoxia inducible factor-1α (HIF-1α) was used as a hypoxia marker. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining were conducted to evaluate cell death. Hypoxic tumor cells had an impaired response to RT. GNPs combined with RT enhanced anti-tumor effect in hypoxic tumor compared with RT alone. The combination of GNPs and RT decreased tumor cell viability compare to RT alone in vitro. Under hypoxia, tumors treated with GNPs + RT showed a higher response than that shown by tumors treated with RT alone. When a reactive oxygen species (ROS) scavenger was added, the enhanced antitumor effect of GNPs + RT was diminished. In the present study, hypoxic tumors treated with GNPs + RT showed favorable responses, which might be attributable to the ROS production induced by GNPs + RT. Taken together, GNPs combined with RT seems to be potential modality for enhancing the response to RT in hypoxic tumors

  6. Gold namoprtices enhance anti-tumor effect of radiotherapy to hypoxic tumor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Mi Sun; Lee, Eun Jung; Kim, Jae Won; Keum, Ki Chang; Koom, Woong Sub [Dept. of Radiation Oncology, Yonsei University College of Medicine, Seoul (Korea, Republic of); Chung, Ui Seok; Koh, Won Gun [Dept. of Chemical and Biomolecular Engineering, Yonsei University, Seoul (Korea, Republic of)

    2016-09-15

    Hypoxia can impair the therapeutic efficacy of radiotherapy (RT). Therefore, a new strategy is necessary for enhancing the response to RT. In this study, we investigated whether the combination of nanoparticles and RT is effective in eliminating the radioresistance of hypoxic tumors. Gold nanoparticles (GNPs) consisting of a silica core with a gold shell were used. CT26 colon cancer mouse model was developed to study whether the combination of RT and GNPs reduced hypoxia-induced radioresistance. Hypoxia inducible factor-1α (HIF-1α) was used as a hypoxia marker. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining were conducted to evaluate cell death. Hypoxic tumor cells had an impaired response to RT. GNPs combined with RT enhanced anti-tumor effect in hypoxic tumor compared with RT alone. The combination of GNPs and RT decreased tumor cell viability compare to RT alone in vitro. Under hypoxia, tumors treated with GNPs + RT showed a higher response than that shown by tumors treated with RT alone. When a reactive oxygen species (ROS) scavenger was added, the enhanced antitumor effect of GNPs + RT was diminished. In the present study, hypoxic tumors treated with GNPs + RT showed favorable responses, which might be attributable to the ROS production induced by GNPs + RT. Taken together, GNPs combined with RT seems to be potential modality for enhancing the response to RT in hypoxic tumors.

  7. Population Blocks.

    Science.gov (United States)

    Smith, Martin H.

    1992-01-01

    Describes an educational game called "Population Blocks" that is designed to illustrate the concept of exponential growth of the human population and some potential effects of overpopulation. The game material consists of wooden blocks; 18 blocks are painted green (representing land), 7 are painted blue (representing water); and the remaining…

  8. Dissection of a Hypoxia-induced, Nitric Oxide–mediated Signaling Cascade

    Science.gov (United States)

    Dijkers, Pascale F.

    2009-01-01

    Befitting oxygen's key role in life's processes, hypoxia engages multiple signaling systems that evoke pervasive adaptations. Using surrogate genetics in a powerful biological model, we dissect a poorly understood hypoxia-sensing and signal transduction system. Hypoxia triggers NO-dependent accumulation of cyclic GMP and translocation of cytoplasmic GFP-Relish (an NFκB/Rel transcription factor) to the nucleus in Drosophila S2 cells. An enzyme capable of eliminating NO interrupted signaling specifically when it was targeted to the mitochondria, arguing for a mitochondrial NO signal. Long pretreatment with an inhibitor of nitric oxide synthase (NOS), L-NAME, blocked signaling. However, addition shortly before hypoxia was without effect, suggesting that signaling is supported by the prior action of NOS and is independent of NOS action during hypoxia. We implicated the glutathione adduct, GSNO, as a signaling mediator by showing that overexpression of the cytoplasmic enzyme catalyzing its destruction, GSNOR, blocks signaling, whereas knockdown of this activity caused reporter translocation in the absence of hypoxia. In downstream steps, cGMP accumulated, and calcium-dependent signaling was subsequently activated via cGMP-dependent channels. These findings reveal the use of unconventional steps in an NO pathway involved in sensing hypoxia and initiating signaling. PMID:19625446

  9. Dissection of a hypoxia-induced, nitric oxide-mediated signaling cascade.

    Science.gov (United States)

    Dijkers, Pascale F; O'Farrell, Patrick H

    2009-09-01

    Befitting oxygen's key role in life's processes, hypoxia engages multiple signaling systems that evoke pervasive adaptations. Using surrogate genetics in a powerful biological model, we dissect a poorly understood hypoxia-sensing and signal transduction system. Hypoxia triggers NO-dependent accumulation of cyclic GMP and translocation of cytoplasmic GFP-Relish (an NFkappaB/Rel transcription factor) to the nucleus in Drosophila S2 cells. An enzyme capable of eliminating NO interrupted signaling specifically when it was targeted to the mitochondria, arguing for a mitochondrial NO signal. Long pretreatment with an inhibitor of nitric oxide synthase (NOS), L-NAME, blocked signaling. However, addition shortly before hypoxia was without effect, suggesting that signaling is supported by the prior action of NOS and is independent of NOS action during hypoxia. We implicated the glutathione adduct, GSNO, as a signaling mediator by showing that overexpression of the cytoplasmic enzyme catalyzing its destruction, GSNOR, blocks signaling, whereas knockdown of this activity caused reporter translocation in the absence of hypoxia. In downstream steps, cGMP accumulated, and calcium-dependent signaling was subsequently activated via cGMP-dependent channels. These findings reveal the use of unconventional steps in an NO pathway involved in sensing hypoxia and initiating signaling.

  10. Inhibition of tumor growth by targeted anti-EGFR/IGF-1R Nanobullets depends on efficient blocking of cell survival pathways

    NARCIS (Netherlands)

    van der Meel, Roy; Oliveira, Sabrina; Altintas, Isil; Heukers, R.; Pieters, Ebel H.E.; van Bergen en Henegouwen, Paul M.P.; Storm, Gerrit; Hennink, Wim E.; Kok, Robbert J.; Schiffelers, Raymond M.

    2013-01-01

    The clinical efficacy of epidermal growth factor receptor (EGFR)-targeted inhibitors is limited due to resistance mechanisms of the tumor such as activation of compensatory pathways. Crosstalk between EGFR and insulin-like growth factor 1 (IGF-1R) signaling has been frequently described to be

  11. Hypoxia in atherosclerosis and inflammation

    NARCIS (Netherlands)

    Marsch, Elke; Sluimer, Judith C.; Daemen, Mat J. A. P.

    2013-01-01

    Hypoxia triggers various cellular processes, both in physiological and pathological conditions, and has recently also been implicated in atherosclerosis. This review summarizes the recent evidence for the presence and the role of hypoxia in atherosclerosis. Additionally, it will elucidate on hypoxic

  12. Chronic inhibition of tumor cell-derived VEGF enhances the malignant phenotype of colorectal cancer cells

    International Nuclear Information System (INIS)

    Yamagishi, Naoko; Teshima-Kondo, Shigetada; Masuda, Kiyoshi; Nishida, Kensei; Kuwano, Yuki; Dang, Duyen T; Dang, Long H; Nikawa, Takeshi; Rokutan, Kazuhito

    2013-01-01

    Vascular endothelial growth factor-a (VEGF)-targeted therapies have become an important treatment for a number of human malignancies. The VEGF inhibitors are actually effective in several types of cancers, however, the benefits are transiently, and the vast majority of patients who initially respond to the therapies will develop resistance. One of possible mechanisms for the acquired resistance may be the direct effect(s) of VEGF inhibitors on tumor cells expressing VEGF receptors (VEGFR). Thus, we investigated here the direct effect of chronic VEGF inhibition on phenotype changes in human colorectal cancer (CRC) cells. To chronically inhibit cancer cell-derived VEGF, human CRC cell lines (HCT116 and RKO) were chronically exposed (2 months) to an anti-VEGF monoclonal antibody (mAb) or were disrupted the Vegf gene (VEGF-KO). Effects of VEGF family members were blocked by treatment with a VEGF receptor tyrosine kinase inhibitor (VEGFR-TKI). Hypoxia-induced apoptosis under VEGF inhibited conditions was measured by TUNEL assay. Spheroid formation ability was assessed using a 3-D spheroid cell culture system. Chronic inhibition of secreted/extracellular VEGF by an anti-VEGF mAb redundantly increased VEGF family member (PlGF, VEGFR1 and VEGFR2), induced a resistance to hypoxia-induced apoptosis, and increased spheroid formation ability. This apoptotic resistance was partially abrogated by a VEGFR-TKI, which blocked the compensate pathway consisted of VEGF family members, or by knockdown of Vegf mRNA, which inhibited intracellular function(s) of all Vegf gene products. Interestingly, chronic and complete depletion of all Vegf gene products by Vegf gene knockout further augmented these phenotypes in the compensate pathway-independent manner. These accelerated phenotypes were significantly suppressed by knockdown of hypoxia-inducible factor-1α that was up-regulated in the VEGF-KO cell lines. Our findings suggest that chronic inhibition of tumor cell-derived VEGF

  13. Acute hypoxia induces upregulation of microRNA-210 expression in glioblastoma spheroids

    DEFF Research Database (Denmark)

    Rosenberg, Tine Agerbo; Thomassen, Mads; Jensen, Stine Skov

    2015-01-01

    AIM: Tumor hypoxia and presence of tumor stem cells are related to therapeutic resistance and tumorigenicity in glioblastomas. The aim of the present study was therefore to identify microRNAs deregulated in acute hypoxia and to identify possible associated changes in stem cell markers. MATERIALS...... & METHODS: Glioblastoma spheroid cultures were grown in either 2 or 21% oxygen. Subsequently, miRNA profiling was performed and expression of ten stem cell markers was examined. RESULTS: MiRNA-210 was significantly upregulated in hypoxia in patient-derived spheroids. The stem cell markers displayed...... a complex regulatory pattern. CONCLUSION: MiRNA-210 appears to be upregulated in hypoxia in immature glioblastoma cells. This miRNA may represent a therapeutic target although it is not clear from the results whether this miRNA may be related to specific cancer stem cell functions....

  14. Transient hypoxia reprograms differentiating adipocytes for enhanced insulin sensitivity and triglyceride accumulation

    Science.gov (United States)

    Lu, Hongyun; Gao, Zhanguo; Zhao, Zhiyun; Weng, Jianping; Ye, Jianping

    2015-01-01

    Objective To investigate the impact of transient (2-4 h) hypoxia on metabolic reprogramming of adipocytes. Methods The impact of transient hypoxia on metabolic reprogramming was investigated in 3T3-L1 cells before and after differentiation. Glucose uptake, fatty acid oxidation, lipolysis, and mitochondria were examined to determine the hypoxia effects. Preadipocytes were exposed to transient hypoxia (4h/day) in the course of differentiation. Insulin sensitivity and TG accumulation was examined in the cells at the end of differentiation to determine the reprogramming effects. AMPK activity and gene expression were determined by quantitative RT-PCR and Western blotting in search for mechanism of the reprogramming. Results In acute response to hypoxia, adipocytes exhibited an increase in insulin-dependent and -independent glucose uptake. Fatty acid β-oxidation and pyruvate dehydrogenase (PDH) activity were decreased. Multiple exposures of differentiating adipocytes to transient hypoxia enhanced insulin signaling, TG accumulation, expression of antioxidant genes in differentiated adipocytes in the absence of hypoxia. The metabolic memory was associated with elevated AMPK activity and gene expression (GLUT1, PGC-1α, PPARγ, SREBP, NRF-1, ESRRα, LPL). The enhanced insulin sensitivity was blocked by an AMPK inhibitor. Conclusions Repeated exposure of differentiating adipocytes to transient hypoxia is able to reprogram the cells for increased TG accumulation and enhanced insulin sensitivity. The metabolic alterations were observed in post-differentiated cells under normoxia. The reprogramming involves AMPK activation and gene expression in the metabolic pathways in cytosol and mitochondria. PMID:26219415

  15. Chronic hypoxia during gestation enhances uterine arterial myogenic tone via heightened oxidative stress.

    Directory of Open Access Journals (Sweden)

    Daliao Xiao

    Full Text Available Chronic hypoxia during gestation has profound adverse effects on the adaptation of uteroplacental circulation in pregnancy. Yet, the underlying mechanisms are not fully understood. The present study tested the hypothesis that enhanced production of reactive oxygen species (ROS in uterine arteries plays a critical role in the maladaptation of uterine circulation associated with chronic hypoxia. Uterine arteries were isolated from nonpregnant and near-term pregnant sheep maintained at sea level (~300 m or exposed to high-altitude (3801 m hypoxia for 110 days. Hypoxia significantly increased ROS production in uterine arteries of pregnant, but not nonpregnant, sheep. This was associated with a significant increase in NADPH oxidase (Nox 2, but not Nox1 or Nox4, protein abundance and total Nox activity in uterine arteries of pregnant animals. Chronic hypoxia significantly increased pressure-dependent uterine arterial myogenic tone in pregnant sheep, which was abrogated by a Nox inhibitor apocynin. Additionally, the hypoxia-induced increase in myogenic reactivity of uterine arteries to phorbol 12,13-dibutyrate in pregnant sheep was blocked by apocynin and tempol. In consistence with the myogenic responses, the hypoxia-mediated down-regulation of BKCa channel activity in uterine arteries of pregnant animals was reversed by apocynin. The findings suggest that heightened oxidative stress in uterine arteries plays a key role in suppressing the BKCa channel activity, resulting in increased myogenic reactivity and maladaptation of uteroplacental circulation caused by chronic hypoxia during gestation.

  16. Tumor radiation responses and tumor oxygenation in aging mice

    International Nuclear Information System (INIS)

    Rockwell, S.

    1989-01-01

    EMT6 mouse mammary tumors transplanted into aging mice are less sensitive to radiation than tumors growing in young adult animals. The experiments reported here compare the radiation dose-response curves defining the survivals of tumor cells in aging mice and in young adult mice. Cell survival curves were assessed in normal air-breathing mice and in mice asphyxiated with N 2 to produce uniform hypoxia throughout the tumors. Analyses of survival curves revealed that 41% of viable malignant cells were severely hypoxic in tumors in aging mice, while only 19% of the tumor cells in young adult animals were radiobiologically hypoxic. This did not appear to reflect anaemia in the old animals. Treatment of aging animals with a perfluorochemical emulsion plus carbogen (95% O 2 /5% CO 2 ) increased radiation response of the tumors, apparently by improving tumor oxygenation and decreasing the number of severely hypoxic, radiation resistant cells in the tumors. (author)

  17. The critical role of ERK in death resistance and invasiveness of hypoxia-selected glioblastoma cells

    International Nuclear Information System (INIS)

    Kim, Jee-Youn; Kim, Yong-Jun; Lee, Sun; Park, Jae-Hoon

    2009-01-01

    The rapid growth of tumor parenchyma leads to chronic hypoxia that can result in the selection of cancer cells with a more aggressive behavior and death-resistant potential to survive and proliferate. Thus, identifying the key molecules and molecular mechanisms responsible for the phenotypic changes associated with chronic hypoxia has valuable implications for the development of a therapeutic modality. The aim of this study was to identify the molecular basis of the phenotypic changes triggered by chronic repeated hypoxia. Hypoxia-resistant T98G (HRT98G) cells were selected by repeated exposure to hypoxia and reoxygenation. Cell death rate was determined by the trypan blue exclusion method and protein expression levels were examined by western blot analysis. The invasive phenotype of the tumor cells was determined by the Matrigel invasion assay. Immunohistochemistry was performed to analyze the expression of proteins in the brain tumor samples. The Student T-test and Pearson Chi-Square test was used for statistical analyses. We demonstrate that chronic repeated hypoxic exposures cause T98G cells to survive low oxygen tension. As compared with parent cells, hypoxia-selected T98G cells not only express higher levels of anti-apoptotic proteins such as Bcl-2, Bcl-X L , and phosphorylated ERK, but they also have a more invasive potential in Matrigel invasion chambers. Activation or suppression of ERK pathways with a specific activator or inhibitor, respectively, indicates that ERK is a key molecule responsible for death resistance under hypoxic conditions and a more invasive phenotype. Finally, we show that the activation of ERK is more prominent in malignant glioblastomas exposed to hypoxia than in low grade astrocytic glial tumors. Our study suggests that activation of ERK plays a pivotal role in death resistance under chronic hypoxia and phenotypic changes related to the invasive phenotype of HRT98G cells compared to parent cells

  18. Trichostatin A enhances estrogen receptor-alpha repression in MCF-7 breast cancer cells under hypoxia

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Hyunggyun; Park, Joonwoo; Shim, Myeongguk; Lee, YoungJoo, E-mail: yjlee@sejong.ac.kr

    2016-02-12

    Estrogen receptor (ER) is a crucial determinant of resistance to endocrine therapy, which may change during the progression of breast cancer. We previously showed that hypoxia induces ESR1 gene repression and ERα protein degradation via proteasome-mediated pathway in breast cancer cells. HDAC plays important roles in the regulation of histone and non-histone protein post-translational modification. HDAC inhibitors can induce epigenetic changes and have therapeutic potential for targeting various cancers. Trichostatin A exerts potent antitumor activities against breast cancer cells in vitro and in vivo. In this report, we show that TSA augments ESR1 gene repression at the transcriptional level and downregulates ERα protein expression under hypoxic conditions through a proteasome-mediated pathway. TSA-induced estrogen response element-driven reporter activity in the absence of estrogen was synergistically enhanced under hypoxia; however, TSA inhibited cell proliferation under both normoxia and hypoxia. Our data show that the hypoxia-induced repression of ESR1 and degradation of ERα are enhanced by concomitant treatment with TSA. These findings expand our understanding of hormone responsiveness in the tumor microenvironment; however, additional in-depth studies are required to elucidate the detailed mechanisms of TSA-induced ERα regulation under hypoxia. - Highlights: • TSA augments ESR1 gene repression at the transcriptional level under hypoxia. • TSA downregulates ERα protein expression under hypoxia. • TSA-induced ERα regulation under hypoxia is essential for understanding the behavior and progression of breast cancer.

  19. [Hypoxia and polytrauma].

    Science.gov (United States)

    Ottó, S; Janos, S G

    1976-01-01

    The importance of polytrauma and hypoxia, resp., is discussed by the authors with regard to the mortality and the common effect of these is analysed. It was found that in the mortality of the patients suffered polytraumatism the first place (59,4%) is taken by such lesions, in which simultaneous lesion of the skull and the thorax occurs. The values of the blood gas and the acid-base balance of the patients who had suffered polytraumatism, were examined in the 12th--24th hours proceding the death. It was found that whereas--using the possibilities of the intensive therapy--the values of pH, paCO2 and BE could be kept in a part of the cases between the physiological limits--the paO2 value was under the normal value in all cases--moreover 2/3 of the values fell into the domain between 40--60 mmHg--signifying severe hypoxia. On the basis of the analysis it may be presumed that in the process leading to death of the patients who had suffered polytraumatism the anoxic hypoxy plays considerable role. This is supported also by the earlier data published by the institute, according to which the mortality in itself high--33.8%--of polytraumatism increases to 71.4%, if it is associated hypoxy. Consequently the aim of the therapy must be to exert the greatest activity in order to prevent or to combat, resp., the anoxic hypoxy.

  20. The storage period of the formalin-fixed paraffin-embedded tumor blocks does not influence the concentration and purity of the isolated DNA in a series of 83 renal and thyroid carcinomas.

    Science.gov (United States)

    Nechifor-Boilă, Adela Corina; Loghin, Andrada; Vacariu, Victor; Halaţiu, Vasile Bogdan; Borda, Angela

    2015-01-01

    Optimal recovery of nucleic acids from formalin-fixed paraffin-embedded (FFPE) tissues is highly dependent on a series of pre-extraction steps, mainly related (but not limited) to fixation. The aim of our study was to investigate if the storage period of the FFPE blocks had a significant effect on the isolated DNA. We examined the quantity and purity of the isolated DNA from 83 FFPE blocks, corresponding to malignant thyroid (n=28) and renal (n=55) carcinomas that had been stored in our department for up to eight years. The DNA extraction protocol was based on a precipitation method (MasterPure™ DNA Purification Kit, Epicentre), in accordance to the manufacturer instructions, optimized in our laboratory. A spectrophotometer was used to determine the yield (A260) and purity (A260/A280 ratio) of the isolated DNA. We successfully isolated good DNA quantity and purity from all our study cases (mean concentration: 223.4 ± 104.16 ng/μL; mean A260/A280 ratio: 1.68 ± 0.09). Moreover, no statistically significant differences were observed between tumor blocks stored for 2-3 years and 7-8 years, respectively, both in terms of DNA quantity (p=0.196) and purity (p=0.663). In conclusion, we successfully validated an efficient, reproducible DNA extraction technique that provided a good range of DNA concentrations and purity, regardless the type of tissue (thyroid or kidney). Moreover, we demonstrated that the storage period of the FFPE blocks does not have a significant influence on the DNA quantity and purity.

  1. The histone deacetylase inhibitor, Vorinostat, represses hypoxia inducible factor 1 alpha expression through translational inhibition.

    Directory of Open Access Journals (Sweden)

    Darren M Hutt

    Full Text Available Hypoxia inducible factor 1α (HIF-1α is a master regulator of tumor angiogenesis being one of the major targets for cancer therapy. Previous studies have shown that Histone Deacetylase Inhibitors (HDACi block tumor angiogenesis through the inhibition of HIF-1α expression. As such, Vorinostat (Suberoylanilide Hydroxamic Acid/SAHA and Romidepsin, two HDACis, were recently approved by the Food and Drug Administration (FDA for the treatment of cutaneous T cell lymphoma. Although HDACis have been shown to affect HIF-1α expression by modulating its interactions with the Hsp70/Hsp90 chaperone axis or its acetylation status, the molecular mechanisms by which HDACis inhibit HIF-1α expression need to be further characterized. Here, we report that the FDA-approved HDACi Vorinostat/SAHA inhibits HIF-1α expression in liver cancer-derived cell lines, by a new mechanism independent of p53, prolyl-hydroxylases, autophagy and proteasome degradation. We found that SAHA or silencing of HDAC9 mechanism of action is due to inhibition of HIF-1α translation, which in turn, is mediated by the eukaryotic translation initiation factor--eIF3G. We also highlighted that HIF-1α translation is dramatically inhibited when SAHA is combined with eIF3H silencing. Taken together, we show that HDAC activity regulates HIF-1α translation, with HDACis such as SAHA representing a potential novel approach for the treatment of hepatocellular carcinoma.

  2. ACLY and ACC1 Regulate Hypoxia-Induced Apoptosis by Modulating ETV4 via α-ketoglutarate.

    Directory of Open Access Journals (Sweden)

    Melissa M Keenan

    2015-10-01

    Full Text Available In order to propagate a solid tumor, cancer cells must adapt to and survive under various tumor microenvironment (TME stresses, such as hypoxia or lactic acidosis. To systematically identify genes that modulate cancer cell survival under stresses, we performed genome-wide shRNA screens under hypoxia or lactic acidosis. We discovered that genetic depletion of acetyl-CoA carboxylase (ACACA or ACC1 or ATP citrate lyase (ACLY protected cancer cells from hypoxia-induced apoptosis. Additionally, the loss of ACLY or ACC1 reduced levels and activities of the oncogenic transcription factor ETV4. Silencing ETV4 also protected cells from hypoxia-induced apoptosis and led to remarkably similar transcriptional responses as with silenced ACLY or ACC1, including an anti-apoptotic program. Metabolomic analysis found that while α-ketoglutarate levels decrease under hypoxia in control cells, α-ketoglutarate is paradoxically increased under hypoxia when ACC1 or ACLY are depleted. Supplementation with α-ketoglutarate rescued the hypoxia-induced apoptosis and recapitulated the decreased expression and activity of ETV4, likely via an epigenetic mechanism. Therefore, ACC1 and ACLY regulate the levels of ETV4 under hypoxia via increased α-ketoglutarate. These results reveal that the ACC1/ACLY-α-ketoglutarate-ETV4 axis is a novel means by which metabolic states regulate transcriptional output for life vs. death decisions under hypoxia. Since many lipogenic inhibitors are under investigation as cancer therapeutics, our findings suggest that the use of these inhibitors will need to be carefully considered with respect to oncogenic drivers, tumor hypoxia, progression and dormancy. More broadly, our screen provides a framework for studying additional tumor cell stress-adaption mechanisms in the future.

  3. Hypoxia-Specific Drug Tirapazamine Does Not Abrogate Hypoxic Tumor Cells in Combination Therapy with Irinotecan and Methylselenocysteine in Well-Differentiated Human Head and Neck Squamous Cell Carcinoma A253 Xenografts

    Directory of Open Access Journals (Sweden)

    Arup Bhattacharya

    2008-08-01

    Full Text Available Well-differentiated hypoxic regions in head and neck squamous cell carcinoma like in A253 xenografts are avascular and, therefore, hinder drug delivery leading to drug resistance and tumor regrowth. Methylselenocysteine (MSC, 0.2 mg/mouse per day per oral for 35 days starting 7 days before the first irinotecan (CPT-11 has been found to increase efficacy of a wide variety of chemotherapeutic agents including CPT-11 (100 mg/kg per week x 4 intravenously. Whereas CPT-11 leads to a 10% complete response (CR in A253 xenografts, the combination of MSC and CPT-11 increased the CR to 70%. Surviving tumors were found to consist largely of avascular hypoxic regions. Here, we investigated the combination of tirapazamine (TPZ, 70 mg/kg per week intraperitoneal x 4 administered 3 or 72 hours before CPT-11, a bioreductive drug in clinical trial with selective toxicity for hypoxic cells, with MSC and CPT-11 in further enhancing the cure rates. Tumor response, change in tumor hypoxic regions, and DNA damage were monitored in vivo. Tirapazamine administered 3 hours before CPT-11 in combination with MSC + CPT-11 led to a lower tumor burden. Tirapazamine did not increase cure rate beyond that of MSC + CPT-11 combination and was instead found to decrease cures with no evidence of an increased DNA damage or a significant reduction in avascular hypoxic tumor regions. CD31 immunostaining in A253 demonstrated disruption of tumor vessels by TPZ that could lower cytotoxic drug delivery to carbonic anhydrase IX-positive hypoxic tumor cells and may explain at least partially these unexpected results.

  4. Coastal hypoxia and sediment biogeochemistry

    Directory of Open Access Journals (Sweden)

    J. J. Middelburg

    2009-07-01

    Full Text Available The intensity, duration and frequency of coastal hypoxia (oxygen concentration <63 μM are increasing due to human alteration of coastal ecosystems and changes in oceanographic conditions due to global warming. Here we provide a concise review of the consequences of coastal hypoxia for sediment biogeochemistry. Changes in bottom-water oxygen levels have consequences for early diagenetic pathways (more anaerobic at expense of aerobic pathways, the efficiency of re-oxidation of reduced metabolites and the nature, direction and magnitude of sediment-water exchange fluxes. Hypoxia may also lead to more organic matter accumulation and burial and the organic matter eventually buried is also of higher quality, i.e. less degraded. Bottom-water oxygen levels also affect the organisms involved in organic matter processing with the contribution of metazoans decreasing as oxygen levels drop. Hypoxia has a significant effect on benthic animals with the consequences that ecosystem functions related to macrofauna such as bio-irrigation and bioturbation are significantly affected by hypoxia as well. Since many microbes and microbial-mediated biogeochemical processes depend on animal-induced transport processes (e.g. re-oxidation of particulate reduced sulphur and denitrification, there are indirect hypoxia effects on biogeochemistry via the benthos. Severe long-lasting hypoxia and anoxia may result in the accumulation of reduced compounds in sediments and elimination of macrobenthic communities with the consequences that biogeochemical properties during trajectories of decreasing and increasing oxygen may be different (hysteresis with consequences for coastal ecosystem dynamics.

  5. Inhibition of tumor vasculogenic mimicry and prolongation of host survival in highly aggressive gallbladder cancers by norcantharidin via blocking the ephrin type a receptor 2/focal adhesion kinase/paxillin signaling pathway.

    Directory of Open Access Journals (Sweden)

    Hui Wang

    Full Text Available Vasculogenic mimicry (VM is a newly-defined tumor microcirculation pattern in highly aggressive malignant tumors. We recently reported tumor growth and VM formation of gallbladder cancers through the contribution of the ephrin type a receptor 2 (EphA2/focal adhesion kinase (FAK/Paxillin signaling pathways. In this study, we further investigated the anti-VM activity of norcantharidin (NCTD as a VM inhibitor for gallbladder cancers and the underlying mechanisms. In vivo and in vitro experiments to determine the effects of NCTD on tumor growth, host survival, VM formation of GBC-SD nude mouse xenografts, and vasculogenic-like networks, malignant phenotypes i.e., proliferation, apoptosis, invasion and migration of GBC-SD cells. Expression of VM signaling-related markers EphA2, FAK and Paxillin in vivo and in vitro were examined by immunofluorescence, western blotting and real-time polymerase chain reaction (RT-PCR, respectively. The results showed that after treatment with NCTD, GBC-SD cells were unable to form VM structures when injecting into nude mouse, growth of the xenograft was inhibited and these observations were confirmed by facts that VM formation by three-dimensional (3-D matrix, proliferation, apoptosis, invasion, migration of GBC-SD cells were affected; and survival time of the xenograft mice was prolonged. Furthermore, expression of EphA2, FAK and Paxillin proteins/mRNAs of the xenografts was downregulated. Thus, we concluded that NCTD has potential anti-VM activity against human gallbladder cancers; one of the underlying mechanisms may be via blocking the EphA2/FAK/Paxillin signaling pathway.

  6. Hypoxia attenuates purinergic P2X receptor-induced inflammatory gene expression in brainstem microglia

    Directory of Open Access Journals (Sweden)

    Smith SMC

    2013-08-01

    Full Text Available Stephanie MC Smith,1,2 Gordon S Mitchell,1,2 Scott A Friedle,3 Christine M Sibigtroth,1 Stéphane Vinit,1 Jyoti J Watters1–31Department of Comparative Biosciences, 2Comparative Biomedical Sciences Training Program, 3Program in Cellular and Molecular Biology, University of Wisconsin, Madison, WI, USAAbstract: Hypoxia and increased extracellular nucleotides are frequently coincident in the brainstem. Extracellular nucleotides are potent modulators of microglial inflammatory gene expression via P2X purinergic receptor activation. Although hypoxia is also known to modulate inflammatory gene expression, little is known about how hypoxia or P2X receptor activation alone affects inflammatory molecule production in brainstem microglia, nor how hypoxia and P2X receptor signaling interact when they occur together. In the study reported here, we investigated the ability of a brief episode of hypoxia (2 hours in the presence and absence of the nonselective P2X receptor agonist 2′(3′-O-(4-benzoylbenzoyladenosine-5′-triphosphate (BzATP to promote inflammatory gene expression in brainstem microglia in adult rats. We evaluated inducible nitric oxide synthase (iNOS, tumor necrosis factor alpha (TNFα, and interleukin (IL-6 messenger RNA levels in immunomagnetically isolated brainstem microglia. While iNOS and IL-6 gene expression increased with hypoxia and BzATP alone, TNFα expression was unaffected. Surprisingly, BzATP-induced inflammatory effects were lost after hypoxia, suggesting that hypoxia impairs proinflammatory P2X-receptor signaling. We also evaluated the expression of key P2X receptors activated by BzATP, namely P2X1, P2X4, and P2X7. While hypoxia did not alter their expression, BzATP upregulated P2X4 and P2X7 mRNAs; these effects were ablated in hypoxia. Although both P2X4 and P2X7 receptor expression correlated with increased microglial iNOS and IL-6 levels in microglia from normoxic rats, in hypoxia, P2X7 only correlated with IL-6, and P2X

  7. The role of mRNA translation in the adaptation to hypoxia

    International Nuclear Information System (INIS)

    Koritzinsky, M.; Wouters, B.G.; Koumenis, C.

    2003-01-01

    Hypoxia commonly occurs in human tumours and is associated with a poor prognosis. We and others have shown that global mRNA translation is rapidly inhibited during hypoxia. However, some mRNAs, such as those coding for HIF-1 α and VEGF, remain efficiently translated. We therefore hypothesize that the inhibition of mRNA translation serves to promote hypoxia tolerance in two ways: i) through conservation of energy and ii) through differential gene expression involved in hypoxia adaptation. We are investigating the mechanisms responsible for the down regulation of protein synthesis during hypoxia, and how specific mRNAs maintain their ability to be translated under such conditions. Our goal is to understand the significance of these regulatory mechanisms for hypoxia tolerance in vitro and tumor growth in vivo. We have previously shown that one mechanism responsible for inhibiting protein synthesis during hypoxia is the activation of PERK, which inhibits the essential translation factor eIF2 α . Here we show that PERK-/- MEFs are not able to inhibit protein synthesis efficiently during hypoxia and are significantly less tolerant to hypoxia than wt cells. We also show that other mechanisms are important for sustained low protein synthesis during chronic hypoxia. We demonstrate that the eIF4F complex is disrupted during prolonged hypoxia, and that this is mediated by 4E-BP1 and 4E-T. eIF4F is essential for translation which is dependent upon the 5'mRNA cap-structure. These studies therefore indicate a switch from the inhibition of all translation through eIF2 α during acute hypoxia, to the inhibition of only cap-dependent translation during chronic hypoxia. This model predicts the differential induction of genes that can be translated cap-independently during chronic hypoxia, which is consistent with the observed differential translation of HIF-1 α and VEGF. The functional significance of the disruption of the eIF4F complex during hypoxia is currently being addressed

  8. Blocking Tim-3 or/and PD-1 reverses dysfunction of tumor-infiltrating lymphocytes in HBV-related hepatocellular carcinoma.

    Science.gov (United States)

    Liu, Furong; Zeng, Gucheng; Zhou, Shaotang; He, Xiaoshun; Sun, Nianfeng; Zhu, Xiaofeng; Hu, Anbin

    2018-03-22

    The immunosuppression of tumor-infiltrating lymphocytes (TILs) is associated with rapid progression of hepatitis B virus-related hepatocellular carcinoma (HBV-HCC). T cell Ig- and mucin-domain-containing molecule-3 (Tim-3) and programmed cell death 1 (PD-1) are important inhibitory molecules expressed on the surface of T cells, but their roles in the function of TILs in HBV-HCC are poorly understood. We aimed to study the roles of these two markers in HBV-HCC. Ninety patients with pathologically confirmed HBV-associated HCC were enrolled in our study. Blood samples, paired fresh tumor tissues and adjacent tissues were collected, and isolating peripheral blood mononuclear cells, TILs and adjacent-infiltrating lymphocytes were isolated from these samples. The patients were followed-up to allow survival analysis. Tim-3 or/and PD-1 was up-regulated expressed on CD4 + and CD8 + TILs in HBV-HCC patients and a higher proportion of TILs expressed PD-1 alone. Tim-3 + and PD-1 + TILs greatly decreased secretion of IFN-γ and TNF-α. Expression of Tim-3 and PD-1 on TILs negatively correlated with disease-free survival of HCC patients. Direct blockade of Tim-3 and PD-1 in vitro significantly enhanced TILs proliferation and secretion of IFN-γ and TNF-α. Expression of Tim-3 and/or PD-1 on TILs impairs their function and correlates negatively with disease-free survival in HBV-HCC. Direct blockade of Tim-3 and PD-1 restores anti-tumor effects of TILs, which suggests a potential target for novel immunotherapy in HBV-HCC. Copyright © 2018 Société Française du Cancer. Published by Elsevier Masson SAS. All rights reserved.

  9. The impact of hypoxia and oxygenation modification on the radiation response of an intracranial rat glioma

    International Nuclear Information System (INIS)

    Bean, J.M.; Archer, G.E.; Munley, M.T.; Ong, E.; Snyder, S.A.; Haroon, Z.A.; McLendon, R.E.; Marks, L.B.; Stratford, M.R.L.; Chaplin, D.J.; Brizel, D.M.; Bigner, D.D.; Dewhirst, M.W.

    1997-01-01

    Purpose: The median survival for a patient treated for GBM is 1 year. Reasons for the poor long term benefit of conventional therapy, which includes radiation therapy, are poorly understood. Gliomas have areas of hypoxia which may predict for radioresistance. The purpose of this project was to test the hypothesis that hyperbaric oxygen was superior to nicotinamide plus carbogen in decreasing the extent of hypoxia and in increasing survival following fractionated irradiation in an intracranial glioma tumor model. Materials and Methods: RG-2 tumor cells were transplanted intracranially into female Fischer 344 rats. Hypoxia was studied using immunohistochemical staining of drug-protein adducts in tumor following removal of the brain after i.p. injection of pimonidazole hydrochloride under conditions of room air, 3 atmospheres oxygen (HBO), or nicotinamide (200 mg/kg i.p.) with carbogen. Serum nicotinamide and metabolites were measured by HPLC on samples taken 20 minutes after giving nicotinamide (200 mg/kg, i.p.). In a survival study animals were randomized on day 14 post-transplant to 1 of 4 treatment groups: 1) sham - anesthesia only; 2) XRT - 4 Gy x 5; 3) HBO - XRT after breathing for 5 minutes once 3 atmospheres of 100% oxygen was obtained; and 4) Carbogen/Nicotinamide - XRT with i.p. nicotinamide 20 minutes prior to irradiation and carbogen breathing for 5 minutes after saturation of the chamber. Following treatment, animals were followed until death. Results: Immunohistochemical evaluation of the tumors from animals breathing room air revealed pimonidazole adducts indicating the presence of hypoxia. Those tumors evaluated from animals treated with HBO did not show evidence of hypoxia marker binding. The median serum nicotinamide level obtained was 258.2 μg/ml. Median survivals post-transplant were: 1) Sham - 22 days; 2) XRT - 28 days; 3) HBO - 28 days; and 4) Carbogen/Nicotinamide - 26 days. Only XRT and HBO were statistically better than Sham (p = 0.002 and p

  10. Blocking C5aR signaling promotes the anti-tumor efficacy of PD-1/PD-L1 blockade.

    Science.gov (United States)

    Zha, Haoran; Han, Xiao; Zhu, Ying; Yang, Fei; Li, Yongsheng; Li, Qijing; Guo, Bo; Zhu, Bo

    2017-01-01

    Anti-PD-1/PD-L1 therapy has achieved great success in the clinic; however, only a small fraction of cancer patient benefit from PD-1/PD-L1 blockade therapy, and overcoming resistance to PD-1/PD-L1 blockade has thus become a primary priority. In this study, we demonstrated that administration of PD-1/PD-L1 antibodies resulted in the activation of the complement system and massive generation of C5a. Generation of C5a did not change the accumulation of MDSCs in either the tumor or spleen but enhanced their inhibitory potential. In addition, blockade of C5a-C5aR signaling in combination with PD-1/PD-L1 antibodies greatly enhanced the anti-tumor efficacy of PD-1/PD-L1 antibodies. Overall, these data indicate an immunosuppressive role of C5a in the context of PD-1/PD-L1 blockade therapy and provide a strong incentive to clinically explore combination therapies using a C5a antagonist.

  11. Chronic hypoxia promotes pulmonary artery endothelial cell proliferation through H2O2-induced 5-lipoxygenase.

    Directory of Open Access Journals (Sweden)

    Kristi M Porter

    Full Text Available Pulmonary Hypertension (PH is a progressive disorder characterized by endothelial dysfunction and proliferation. Hypoxia induces PH by increasing vascular remodeling. A potential mediator in hypoxia-induced PH development is arachidonate 5-Lipoxygenase (ALOX5. While ALOX5 metabolites have been shown to promote pulmonary vasoconstriction and endothelial cell proliferation, the contribution of ALOX5 to hypoxia-induced proliferation remains unknown. We hypothesize that hypoxia exposure stimulates HPAEC proliferation by increasing ALOX5 expression and activity. To test this, human pulmonary artery endothelial cells (HPAEC were cultured under normoxic (21% O2 or hypoxic (1% O2 conditions for 24-, 48-, or 72 hours. In a subset of cells, the ALOX5 inhibitor, zileuton, or the 5-lipoxygenase activating protein inhibitor, MK-886, was administered during hypoxia exposure. ALOX5 expression was measured by qRT-PCR and western blot and HPAEC proliferation was assessed. Our results demonstrate that 24 and 48 hours of hypoxia exposure have no effect on HPAEC proliferation or ALOX5 expression. Seventy two hours of hypoxia significantly increases HPAEC ALOX5 expression, hydrogen peroxide (H2O2 release, and HPAEC proliferation. We also demonstrate that targeted ALOX5 gene silencing or inhibition of the ALOX5 pathway by pharmacological blockade attenuates hypoxia-induced HPAEC proliferation. Furthermore, our findings indicate that hypoxia-induced increases in cell proliferation and ALOX5 expression are dependent on H2O2 production, as administration of the antioxidant PEG-catalase blocks these effects and addition of H2O2 to HPAEC promotes proliferation. Overall, these studies indicate that hypoxia exposure induces HPAEC proliferation by activating the ALOX5 pathway via the generation of H2O2.

  12. Effects of hypoxia on human cancer cell line chemosensitivity

    Science.gov (United States)

    2013-01-01

    Background Environment inside even a small tumor is characterized by total (anoxia) or partial oxygen deprivation, (hypoxia). It has been shown that radiotherapy and some conventional chemotherapies may be less effective in hypoxia, and therefore it is important to investigate how different drugs act in different microenvironments. In this study we perform a large screening of the effects of 19 clinically used or experimental chemotherapeutic drugs on five different cell lines in conditions of normoxia, hypoxia and anoxia. Methods A panel of 19 commercially available drugs: 5-fluorouracil, acriflavine, bortezomib, cisplatin, digitoxin, digoxin, docetaxel, doxorubicin, etoposide, gemcitabine, irinotecan, melphalan, mitomycin c, rapamycin, sorafenib, thalidomide, tirapazamine, topotecan and vincristine were tested for cytotoxic activity on the cancer cell lines A2780 (ovarian), ACHN (renal), MCF-7 (breast), H69 (SCLC) and U-937 (lymphoma). Parallel aliquots of the cells were grown at different oxygen pressures and after 72 hours of drug exposure viability was measured with the fluorometric microculture cytotoxicity assay (FMCA). Results Sorafenib, irinotecan and docetaxel were in general more effective in an oxygenated environment, while cisplatin, mitomycin c and tirapazamine were more effective in a low oxygen environment. Surprisingly, hypoxia in H69 and MCF-7 cells mostly rendered higher drug sensitivity. In contrast ACHN appeared more sensitive to hypoxia, giving slower proliferating cells, and consequently, was more resistant to most drugs. Conclusions A panel of standard cytotoxic agents was tested against five different human cancer cell lines cultivated at normoxic, hypoxic and anoxic conditions. Results show that impaired chemosensitivity is not universal, in contrast different cell lines behave different and some drugs appear even less effective in normoxia than hypoxia. PMID:23829203

  13. Impaired response of mature adipocytes of diabetic mice to hypoxia

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Seok Jong, E-mail: seok-hong@northwestern.edu; Jin, Da P.; Buck, Donald W.; Galiano, Robert D.; Mustoe, Thomas A., E-mail: tmustoe@nmh.org

    2011-10-01

    Adipose tissue contains various cells such as infiltrated monocytes/macrophages, endothelial cells, preadipocytes, and adipocytes. Adipocytes have an endocrine function by secreting adipokines such as interleukin (IL)-6, tumor necrosis factor (TNF)-{alpha}, leptin, and adiponectin. Dysregulation of adipokines in adipose tissues leads to a chronic low-grade inflammation which could result in atherosclerosis, hypertension, and type 2 diabetes. A sustained inflammatory state, which is characterized by prolonged persistence of macrophages and neutrophils, is found in diabetic wounds. In addition, subcutaneous adipocytes are enormously increased in amount clinically in type 2 diabetes. However, the function of subcutaneous adipocytes, which play an important role in injured tissue subjected to hypoxia, has not been well characterized in vitro due to the difficulty of maintaining mature adipocytes in culture using conventional methods because of their buoyancy. In this study, we established a novel in vitro culture method of mature adipocytes by enclosing them in a hyaluronan (HA) based hydrogel to study their role in response to stress such as hypoxia. BrdU labeling and Ki67 immunostaining experiments showed that hydrogel enclosed mature adipocytes proliferate in vitro. Both mRNA and protein expression analyses for hypoxia regulated genes, such as vascular endothelial growth factor (VEGF) and heme oxygenase 1 (HO1), showed that mature adipocytes of wild type mice respond to hypoxia. In contrast, mature adipocytes of diabetic db/db and TallyHo mice did not efficiently respond to hypoxia. Our studies suggest that mature adipocytes are functionally active cells, and their abnormal function to hypoxia can be one of underlining mechanisms in type 2 diabetes.

  14. Disrupting galectin-1 interactions with N-glycans suppresses hypoxia-driven angiogenesis and tumorigenesis in Kaposi’s sarcoma

    Science.gov (United States)

    Croci, Diego O.; Salatino, Mariana; Rubinstein, Natalia; Cerliani, Juan P.; Cavallin, Lucas E.; Leung, Howard J.; Ouyang, Jing; Ilarregui, Juan M.; Toscano, Marta A.; Domaica, Carolina I.; Croci, María C.; Shipp, Margaret A.; Mesri, Enrique A.; Albini, Adriana

    2012-01-01

    Kaposi’s sarcoma (KS), a multifocal vascular neoplasm linked to human herpesvirus-8 (HHV-8/KS-associated herpesvirus [KSHV]) infection, is the most common AIDS-associated malignancy. Clinical management of KS has proven to be challenging because of its prevalence in immunosuppressed patients and its unique vascular and inflammatory nature that is sustained by viral and host-derived paracrine-acting factors primarily released under hypoxic conditions. We show that interactions between the regulatory lectin galectin-1 (Gal-1) and specific target N-glycans link tumor hypoxia to neovascularization as part of the pathogenesis of KS. Expression of Gal-1 is found to be a hallmark of human KS but not other vascular pathologies and is directly induced by both KSHV and hypoxia. Interestingly, hypoxia induced Gal-1 through mechanisms that are independent of hypoxia-inducible factor (HIF) 1α and HIF-2α but involved reactive oxygen species–dependent activation of the transcription factor nuclear factor κB. Targeted disruption of Gal-1–N-glycan interactions eliminated hypoxia-driven angiogenesis and suppressed tumorigenesis in vivo. Therapeutic administration of a Gal-1–specific neutralizing mAb attenuated abnormal angiogenesis and promoted tumor regression in mice bearing established KS tumors. Given the active search for HIF-independent mechanisms that serve to couple tumor hypoxia to pathological angiogenesis, our findings provide novel opportunities not only for treating KS patients but also for understanding and managing a variety of solid tumors. PMID:23027923

  15. Diacetoxyscirpenol as a new anticancer agent to target hypoxia-inducible factor 1

    Science.gov (United States)

    Choi, Yong-Joon; Shin, Hyun-Woo; Chun, Yang-Sook; Leutou, Alain Simplice; Son, Byeng Wha; Park, Jong-Wan

    2016-01-01

    Hypoxia activates hypoxia-inducible factor 1, which promotes the progression of malignancy by stimulating angiogenesis and by augmenting the ability of tumors to survive. Thus, HIF-1 is one of the most compelling targets for treating cancers. The aim of this study was to find a small molecule that inhibits HIF-1 under hypoxia in cancer cells. 7,280 compounds in a chemical library were tested in a cancer cell line expressing luciferase HIF-dependently. Through three rounds of screening, we finally picked up a compound that originates from a marine bacterium parasitizing red alga. The antibiotic potently inhibited HIF-1 expression and its transcriptional activity in cancer cells exposed to hypoxia. Through two-step fractionation, diacetoxyscirpenol was purified and identified as a HIF-inhibiting ingredient. Mechanistically, diacetoxyscirpenol inhibits the synthesis of HIF-1α protein and also interferes with the dimerization of HIF-1α and ARNT. It attenuates HIF-mediated gene expression in cancer cells exposed to hypoxia, and by doing so reduces tumorigenic and angiogenic potentials of cancer cells. More importantly, diacetoxyscirpenol retarded tumor growth in mice, and reduced HIF-1α expression and vascular formation in the tumors. Overall, diacetoxyscirpenol is considered a potential drug deregulating the HIF-1 signaling pathway, and it could be beneficially employed for treating malignant tumors with hypoxic microenvironment. PMID:27613833

  16. Dynamic contrast enhanced magnetic resonance imaging for hypoxia mapping and potential for brachytherapy targeting

    Directory of Open Access Journals (Sweden)

    Anna Li

    2017-03-01

    Full Text Available Background and purpose: Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI may be used to visualize tumor hypoxia, and was in this work explored in treatment planning of hypoxia-guided brachytherapy of patients with locally advanced cervical cancer (LACC. Materials and methods: Pharmacokinetic ABrix maps were derived from DCE-MR images taken prior to chemoradiotherapy of 78 patients with LACC. A logistic regression procedure was used to segment the tumor volume fraction from the ABrix maps that showed the strongest association with patient survival, denoted biological target volume (BTV fraction. A hypoxia gene score was calculated from a biopsy-based gene signature and correlated against the BTV fraction. Brachytherapy planning based on the ABrix maps was performed, for 23 patients. A general planning aim was a minimum D90 dose of 7.5 Gy to the tumor per brachytherapy fraction. Two planning approaches were explored: (1 a conventional uniform and (2 a non-uniform approach targeting the BTV to the highest dose possible. Results: The segmented BTV fraction was significantly associated local and locoregional control (P = 0.025 and the hypoxia gene score (P = 0.002. Comparing brachytherapy approaches 1 and 2, it was possible to dose escalate the BTV with 0.4 Gy per fraction in median (D90; cohort range [0, 3.8]. Some tumors could not be dose escalated without violating the dose constraints to the organs at risk. Conclusions: Tumor regions associated with hypoxia may be targeted with brachytherapy. The presented methodology may become useful in future strategies to improve cure probability of resistant tumors. Keywords: Hypoxia, Uterine cervical cancer, Computer-assisted image analysis, Magnetic resonance imaging, Brachytherapy

  17. Design of optimized hypoxia-activated prodrugs using pharmacokinetic/pharmacodynamic modeling

    Directory of Open Access Journals (Sweden)

    Annika Bettina Foehrenbacher

    2013-12-01

    Full Text Available Hypoxia contributes to resistance of tumors to some cytotoxic drugs and to radiotherapy, but can in principle be exploited with hypoxia-activated prodrugs (HAP. HAP in clinical development fall into two broad groups. Class I HAP (like the benzotriazine N-oxides tirapazamine and SN30000, are activated under relatively mild hypoxia. In contrast, Class II HAP (such as the nitro compounds PR-104A or TH-302 are maximally activated only under extreme hypoxia, but their active metabolites (effectors diffuse to cells at intermediate O2 and thus also eliminate moderately hypoxic cells. Here, we use a spatially resolved pharmacokinetic/pharmacodynamic (SR-PK/PD model to compare these two strategies and to identify the features required in an optimal Class II HAP. The model uses a Green’s function approach to calculate spatial and longitudinal gradients of O2, prodrug and effector concentrations, and resulting killing in a digitized 3D tumor microregion to estimate activity as monotherapy and in combination with radiotherapy. An analogous model for a normal tissue with mild hypoxia and short intervesssel distances (based on a cremaster muscle microvessel network was used to estimate tumor selectivity of cell killing. This showed that Class II HAP offer advantages over Class I including higher tumor selectivity and greater freedom to vary prodrug diffusibility and rate of metabolic activation. The model suggests that the largest gains in class II HAP antitumor activity could be realized by optimizing effector stability and prodrug activation rates. We also use the model to show that diffusion of effector into blood vessels is unlikely to materially increase systemic exposure for realistic tumor burdens and effector clearances. However, we show that the tumor selectivity achievable by hypoxia-dependent prodrug activation alone is limited if dose-limiting normal tissues are even mildly hypoxic

  18. Hypoxia, Oxidative Stress and Fat

    Directory of Open Access Journals (Sweden)

    Nikolaus Netzer

    2015-06-01

    Full Text Available Metabolic disturbances in white adipose tissue in obese individuals contribute to the pathogenesis of insulin resistance and the development of type 2 diabetes mellitus. Impaired insulin action in adipocytes is associated with elevated lipolysis and increased free fatty acids leading to ectopic fat deposition in liver and skeletal muscle. Chronic adipose tissue hypoxia has been suggested to be part of pathomechanisms causing dysfunction of adipocytes. Hypoxia can provoke oxidative stress in human and animal adipocytes and reduce the production of beneficial adipokines, such as adiponectin. However, time-dose responses to hypoxia relativize the effects of hypoxic stress. Long-term exposure of fat cells to hypoxia can lead to the production of beneficial substances such as leptin. Knowledge of time-dose responses of hypoxia on white adipose tissue and the time course of generation of oxidative stress in adipocytes is still scarce. This paper reviews the potential links between adipose tissue hypoxia, oxidative stress, mitochondrial dysfunction, and low-grade inflammation caused by adipocyte hypertrophy, macrophage infiltration and production of inflammatory mediators.

  19. Hypoxia-Independent Downregulation of Hypoxia-Inducible Factor 1 Targets by Androgen Deprivation Therapy in Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Ragnum, Harald Bull [Department of Radiation Biology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo (Norway); Røe, Kathrine [Department of Radiation Biology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo (Norway); Division of Medicine, Department of Oncology, Akershus University Hospital, Lørenskog (Norway); Holm, Ruth; Vlatkovic, Ljiljana [Department of Pathology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo (Norway); Nesland, Jahn Marthin [Department of Pathology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo (Norway); Medical Faculty, University of Oslo, Oslo (Norway); Aarnes, Eva-Katrine [Department of Radiation Biology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo (Norway); Ree, Anne Hansen [Division of Medicine, Department of Oncology, Akershus University Hospital, Lørenskog (Norway); Medical Faculty, University of Oslo, Oslo (Norway); Flatmark, Kjersti [Department of Tumor Biology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo (Norway); Department of Gastrointestinal Surgery, The Norwegian Radium Hospital, Oslo University Hospital, Oslo (Norway); Seierstad, Therese [Department of Radiology and Nuclear Medicine, The Norwegian Radium Hospital, Oslo University Hospital, Oslo (Norway); Faculty of Health Sciences, Buskerud University College, Drammen (Norway); Lilleby, Wolfgang [Department of Oncology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo (Norway); Lyng, Heidi, E-mail: heidi.lyng@rr-research.no [Department of Radiation Biology, The Norwegian Radium Hospital, Oslo University Hospital, Oslo (Norway)

    2013-11-15

    Purpose: We explored changes in hypoxia-inducible factor 1 (HIF1) signaling during androgen deprivation therapy (ADT) of androgen-sensitive prostate cancer xenografts under conditions in which no significant change in immunostaining of the hypoxia marker pimonidazole had occurred. Methods and Materials: Gene expression profiles of volume-matched androgen-exposed and androgen-deprived CWR22 xenografts, with similar pimonidazole-positive fractions, were compared. Direct targets of androgen receptor (AR) and HIF1 transcription factors were identified among the differentially expressed genes by using published lists. Biological processes affected by ADT were determined by gene ontology analysis. HIF1α protein expression in xenografts and biopsy samples from 35 patients receiving neoadjuvant ADT was assessed by immunohistochemistry. Results: A total of 1344 genes showed more than 2-fold change in expression by ADT, including 35 downregulated and 5 upregulated HIF1 targets. Six genes were shared HIF1 and AR targets, and their downregulation was confirmed with quantitative RT-PCR. Significant suppression of the biological processes proliferation, metabolism, and stress response in androgen-deprived xenografts was found, consistent with tumor regression. Nineteen downregulated HIF1 targets were involved in those significant biological processes, most of them in metabolism. Four of these were shared AR and HIF1 targets, including genes encoding the regulatory glycolytic proteins HK2, PFKFB3, and SLC2A1. Most of the downregulated HIF1 targets were induced by hypoxia in androgen-responsive prostate cancer cell lines, confirming their role as hypoxia-responsive HIF1 targets in prostate cancer. Downregulation of HIF1 targets was consistent with the absence of HIF1α protein in xenografts and downregulation in patients by ADT (P<.001). Conclusions: AR repression by ADT may lead to downregulation of HIF1 signaling independently of hypoxic fraction, and this may contribute to

  20. Hypoxia-Independent Downregulation of Hypoxia-Inducible Factor 1 Targets by Androgen Deprivation Therapy in Prostate Cancer

    International Nuclear Information System (INIS)

    Ragnum, Harald Bull; Røe, Kathrine; Holm, Ruth; Vlatkovic, Ljiljana; Nesland, Jahn Marthin; Aarnes, Eva-Katrine; Ree, Anne Hansen; Flatmark, Kjersti; Seierstad, Therese; Lilleby, Wolfgang; Lyng, Heidi

    2013-01-01

    Purpose: We explored changes in hypoxia-inducible factor 1 (HIF1) signaling during androgen deprivation therapy (ADT) of androgen-sensitive prostate cancer xenografts under conditions in which no significant change in immunostaining of the hypoxia marker pimonidazole had occurred. Methods and Materials: Gene expression profiles of volume-matched androgen-exposed and androgen-deprived CWR22 xenografts, with similar pimonidazole-positive fractions, were compared. Direct targets of androgen receptor (AR) and HIF1 transcription factors were identified among the differentially expressed genes by using published lists. Biological processes affected by ADT were determined by gene ontology analysis. HIF1α protein expression in xenografts and biopsy samples from 35 patients receiving neoadjuvant ADT was assessed by immunohistochemistry. Results: A total of 1344 genes showed more than 2-fold change in expression by ADT, including 35 downregulated and 5 upregulated HIF1 targets. Six genes were shared HIF1 and AR targets, and their downregulation was confirmed with quantitative RT-PCR. Significant suppression of the biological processes proliferation, metabolism, and stress response in androgen-deprived xenografts was found, consistent with tumor regression. Nineteen downregulated HIF1 targets were involved in those significant biological processes, most of them in metabolism. Four of these were shared AR and HIF1 targets, including genes encoding the regulatory glycolytic proteins HK2, PFKFB3, and SLC2A1. Most of the downregulated HIF1 targets were induced by hypoxia in androgen-responsive prostate cancer cell lines, confirming their role as hypoxia-responsive HIF1 targets in prostate cancer. Downregulation of HIF1 targets was consistent with the absence of HIF1α protein in xenografts and downregulation in patients by ADT (P<.001). Conclusions: AR repression by ADT may lead to downregulation of HIF1 signaling independently of hypoxic fraction, and this may contribute to

  1. HIF1 Contributes to Hypoxia-Induced Pancreatic Cancer Cells Invasion via Promoting QSOX1 Expression

    Directory of Open Access Journals (Sweden)

    Chen-Ye Shi

    2013-08-01

    Full Text Available Background: Quiescin sulfhydryl oxidase 1 (QSOX1, which oxidizes sulfhydryl groups to form disulfide bonds in proteins, is found to be over-expressed in various pancreatic cancer cell lines and patients. QSOX1 promotes invasion of pancreatic cancer cells by activating MMP-2 and MMP-9. However, its regulatory mechanism remains largely undefined. Methods: Real-time PCR and Western blot were employed to detect the expression of QSOX1 in human pancreatic cancer cell lines under hypoxic condition. Luciferase reporter and ChIP assays were used to assess the regulation of QSOX1 by hypoxia-inducible factor 1 (HIF-1. Small interfering RNA (siRNA was applied to knock down endogenous expression of QSOX1. Matrigel-coated invasion chamber essays were conducted to detect the invasion capacity of QSOX1-depleted cells. Results: Both hypoxia and hypoxia mimicking reagent up-regulated the expression of QSOX1 in human pancreatic cancer cell lines. Knockdown of HIF-1α eliminated hypoxia induced QSOX1 expression. HIF-1α was found directly bound to two hypoxia-response elements (HRE of QSOX1 gene, both of which were required for HIF-1 induced QSOX1 expression. Moreover, QSOX1 silencing blocked hypoxia-induced pancreatic cancer cells invasion. Conclusion: QSOX1 is a direct target of HIF-1 and may contribute to hypoxia-induced pancreatic cancer cells invasion.

  2. Modulation of hypoxia-signaling pathways by extracellular linc-RoR.

    Science.gov (United States)

    Takahashi, Kenji; Yan, Irene K; Haga, Hiroaki; Patel, Tushar

    2014-04-01

    Resistance to adverse environmental conditions, such as hypoxia, contributes to the reduced efficacy of anticancer therapies and tumor progression. Although deregulated expression of many long noncoding RNA (lncRNA) occurs in human cancers, the contribution of such RNA to tumor responses to hypoxia are unknown. RNA expression profiling identified several hypoxia-responsive lncRNAs, including the long intergenic noncoding RNA, regulator of reprogramming (linc-RoR), which is also increased in expression in malignant liver cancer cells. Linc-RoR expression was increased in hypoxic regions within tumor cell xenografts in vivo. Tumor cell viability during hypoxia was reduced by small interfering RNA (siRNA) to linc-RoR. Compared with controls, siRNA to linc-RoR decreased phosphorylation of p70S6K1 (RPS6KB1), PDK1 and HIF-1α protein expression and increased expression of the linc-RoR target microRNA-145 (miR-145). Linc-RoR was highly expressed in extracellular RNA released by hepatocellular cancer (HCC) cells during hypoxia. Incubation with extracellular vesicle preparations containing extracellular RNA increased linc-RoR, HIF-1α expression and cell survival in recipient cells. These studies show that linc-RoR is a hypoxia-responsive lncRNA that is functionally linked to hypoxia signaling in HCC through a miR-145-HIF-1α signaling module. Furthermore, this work identifies a mechanistic role for the extracellular transfer of linc-RoR in intercellular signaling to promote cell survival during hypoxic stress.

  3. pO2 Fluctuation Pattern and Cycling Hypoxia in Human Cervical Carcinoma and Melanoma Xenografts

    International Nuclear Information System (INIS)

    Ellingsen, Christine; Øvrebø, Kirsti Marie; Galappathi, Kanthi; Mathiesen, Berit; Rofstad, Einar K.

    2012-01-01

    Purpose: Blood perfusion in tumors is spatially and temporally heterogeneous, resulting in local fluctuations in tissue oxygen tension (pO 2 ) and tissue regions showing cycling hypoxia. In this study, we investigated whether the pO 2 fluctuation pattern and the extent of cycling hypoxia differ between tumor types showing high (e.g., cervical carcinoma xenograft) and low (e.g., melanoma xenograft) fractions of connective tissue-associated blood vessels. Methods and Materials: Two cervical carcinoma lines (CK-160 and TS-415) and two melanoma lines (A-07 and R-18) transplanted into BALB/c nu/nu mice were included in the study. Tissue pO 2 was measured simultaneously in two positions in each tumor by using a two-channel OxyLite fiber-optic oxygen-sensing device. The extent of acute and chronic hypoxia was assessed by combining a radiobiological and a pimonidazole-based immunohistochemical assay of tumor hypoxia. Results: The proportion of tumor regions showing pO 2 fluctuations, the pO 2 fluctuation frequency in these regions, and the relative amplitude of the pO 2 fluctuations were significantly higher in the melanoma xenografts than in the cervical carcinoma xenografts. Cervical carcinoma and melanoma xenografts did not differ significantly in the fraction of acutely hypoxic cells or the fraction of chronically hypoxic cells. However, the ratio between fraction of acutely hypoxic cells and fraction of chronically hypoxic cells was significantly higher in melanoma than in cervical carcinoma xenografts. Conclusions: Temporal heterogeneity in blood flow and tissue pO 2 in tumors may depend on tumor histology. Connective tissue surrounding microvessels may stabilize blood flow and pO 2 and, thus, protect tumor tissue from cycling hypoxia.

  4. Antibodies That Block or Activate Mouse B Cell Activating Factor of the Tumor Necrosis Factor (TNF) Family (BAFF), Respectively, Induce B Cell Depletion or B Cell Hyperplasia*

    Science.gov (United States)

    Kowalczyk-Quintas, Christine; Schuepbach-Mallepell, Sonia; Vigolo, Michele; Willen, Laure; Tardivel, Aubry; Smulski, Cristian R.; Zheng, Timothy S.; Gommerman, Jennifer; Hess, Henry; Gottenberg, Jacques-Eric; Mackay, Fabienne; Donzé, Olivier

    2016-01-01

    B cell activating factor of the TNF family (BAFF), also known as B lymphocyte stimulator, is a ligand required for the generation and maintenance of B lymphocytes. In this study, the ability of different monoclonal antibodies to recognize, inhibit, or activate mouse BAFF was investigated. One of them, a mouse IgG1 named Sandy-2, prevented the binding of BAFF to all of its receptors, BAFF receptor, transmembrane activator and calcium modulating ligand interactor, and B cell maturation antigen, at a stoichiometric ratio; blocked the activity of mouse BAFF on a variety of cell-based reporter assays; and antagonized the prosurvival action of BAFF on primary mouse B cells in vitro. A single administration of Sandy-2 in mice induced B cell depletion within 2 weeks, down to levels close to those observed in BAFF-deficient mice. This depletion could then be maintained with a chronic treatment. Sandy-2 and a previously described rat IgG1 antibody, 5A8, also formed a pair suitable for the sensitive detection of endogenous circulating BAFF by ELISA or using a homogenous assay. Interestingly, 5A8 and Sandy-5 displayed activities opposite to that of Sandy-2 by stimulating recombinant BAFF in vitro and endogenous BAFF in vivo. These tools will prove useful for the detection and functional manipulation of endogenous mouse BAFF and provide an alternative to the widely used BAFF receptor-Fc decoy receptor for the specific depletion of BAFF in mice. PMID:27451394

  5. Hypoxia-inducible factor-1α upregulation in microglia following hypoxia protects against ischemia-induced cerebral infarction.

    Science.gov (United States)

    Huang, Tao; Huang, Weiyi; Zhang, Zhiqiang; Yu, Lei; Xie, Caijun; Zhu, Dongan; Peng, Zizhuang; Chen, Jiehan

    2014-10-01

    Activated microglia were considered to be the toxic inflammatory mediators that induce neuron degeneration after brain ischemia. Hypoxia can enhance the expression of hypoxia-inducible factor-1α (HIF-1α) in microglia and cause microglial activation. However, intermittent hypoxia has been reported recently to be capable of protecting the body from myocardial ischemia. We established a high-altitude environment as the hypoxic condition in this study. The hypoxic condition displayed a neuroprotective effect after brain ischemia, and mice exposed to this condition presented better neurological performance and smaller infarct size. At the same time, a high level of HIF-1α, low level of isoform of nitric oxide synthase, and a reduction in microglial activation were also seen in ischemic focus of hypoxic mice. However, this neuroprotective effect could be blocked by 2-methoxyestradiol, the HIF-1α inhibitor. Our finding suggested that HIF-1α expression was involved in microglial activation in vitro and was regulated by oxygen supply. The microglia were inactivated by re-exposure to hypoxia, which might be due to overexpression of HIF-1α. These results indicated that hypoxic conditions can be exploited to achieve maximum neuroprotection after brain ischemia. This mechanism possibly lies in microglial inactivation through regulation of the expression of HIF-1α.

  6. HDAC6 deacetylase activity is required for hypoxia-induced invadopodia formation and cell invasion.

    Directory of Open Access Journals (Sweden)

    Dominique Arsenault

    Full Text Available Despite significant progress in the cancer field, tumor cell invasion and metastasis remain a major clinical challenge. Cell invasion across tissue boundaries depends largely on extracellular matrix degradation, which can be initiated by formation of actin-rich cell structures specialized in matrix degradation called invadopodia. Although the hypoxic microenvironment within solid tumors has been increasingly recognized as an important driver of local invasion and metastasis, little is known about how hypoxia influences invadopodia biogenesis. Here, we show that histone deacetylase 6 (HDAC6, a cytoplasmic member of the histone deacetylase family, is a novel modulator of hypoxia-induced invadopodia formation. Hypoxia was found to enhance HDAC6 tubulin deacetylase activity through activation of the EGFR pathway. Activated HDAC6, in turn, triggered Smad3 phosphorylation resulting in nuclear accumulation. Inhibition of HDAC6 activity or knockdown of the protein inhibited both hypoxia-induced Smad3 activation and invadopodia formation. Our data provide evidence that hypoxia influences invadopodia formation in a biphasic manner, which involves the activation of HDAC6 deacetylase activity by EGFR, resulting in enhanced Smad phosphorylation and nuclear accumulation. The identification of HDAC6 as a key participant of hypoxia-induced cell invasion may have important therapeutic implications for the treatment of metastasis in cancer patients.

  7. Hypoxia promotes etoposide (VP-16) resistance in neuroblastoma CHP126 cells.

    Science.gov (United States)

    Wang, Duoduo; Zhu, Qionghua; Zhang, Xiayan; Zhang, Lei; He, Qiaojun; Yang, Bo

    2010-01-01

    Hypoxia is widespread in solid tumors as a consequence of poorly structured tumor-derived neovasculature, which is recognized to play a role in the resistance of cancer cells to chemotherapy. Etoposide (VP-16), a drug commonly used in chemotherapy, leads to enhanced accumulation of cell populations in G2/M phase and increases levels of apoptosis as a topoisomerase II inhibitor. We evaluated the effects of hypoxia on the response of the neuroblastoma cell line CHP126 to VP-16, in order to delineate the mechanisms responsible for the hypoxia-induced chemoresistance of this clinically conventional anti-cancer agent, with an insight to determining potential indications in neuroblastoma therapy. In this study, physiological hypoxia was shown to attenuate G2/M arrest and apoptosis induced in CHP126 cells by VP-16. It suppressed drug-related Cdk1 activity with a less elevation of regulator proteins such as cyclin B1, Cdk7 and reduced caspase activation and PARP cleavage compared to the efficiency observed in normoxic condition, which were significantly relative with hypoxia-driven inhibition of p53 and p-ERK1/2 activation. These results clearly demonstrated that hypoxia had a protective effect against VP-16-induced cytotoxicity, which is likely to provide a further therapeutic knowledge in neuroblastomas.

  8. Hypoxia enhances the antiglioma cytotoxicity of B10, a glycosylated derivative of betulinic acid.

    Directory of Open Access Journals (Sweden)

    Sebastian Fischer

    Full Text Available B10 is a glycosylated derivative of betulinic acid with promising activity against glioma cells. Lysosomal cell death pathways appear to be essential for its cytotoxicity. We investigated the influence of hypoxia, nutrient deprivation and current standard therapies on B10 cytotoxicity. The human glioma cell lines LN-308 and LNT-229 were exposed to B10 alone or together with irradiation, temozolomide, nutrient deprivation or hypoxia. Cell growth and viability were evaluated by crystal violet staining, clonogenicity assays, propidium iodide uptake and LDH release assays. Cell death was examined using an inhibitor of lysosomal acidification (bafilomycin A1, a cathepsin inhibitor (CA074-Me and a short-hairpin RNA targeting cathepsin B. Hypoxia substantially enhanced B10-induced cell death. This effect was sensitive to bafilomycin A1 and thus dependent on hypoxia-induced lysosomal acidification. Cathepsin B appeared to mediate cell death because either the inhibitor CA074-Me or cathepsin B gene silencing rescued glioma cells from B10 toxicity under hypoxia. B10 is a novel antitumor agent with substantially enhanced cytotoxicity under hypoxia conferred by increased lysosomal cell death pathway activation. Given the importance of hypoxia for therapy resistance, malignant progression, and as a result of antiangiogenic therapies, B10 might be a promising strategy for hypoxic tumors like malignant glioma.

  9. Antibodies That Block or Activate Mouse B Cell Activating Factor of the Tumor Necrosis Factor (TNF) Family (BAFF), Respectively, Induce B Cell Depletion or B Cell Hyperplasia.

    Science.gov (United States)

    Kowalczyk-Quintas, Christine; Schuepbach-Mallepell, Sonia; Vigolo, Michele; Willen, Laure; Tardivel, Aubry; Smulski, Cristian R; Zheng, Timothy S; Gommerman, Jennifer; Hess, Henry; Gottenberg, Jacques-Eric; Mackay, Fabienne; Donzé, Olivier; Schneider, Pascal

    2016-09-16

    B cell activating factor of the TNF family (BAFF), also known as B lymphocyte stimulator, is a ligand required for the generation and maintenance of B lymphocytes. In this study, the ability of different monoclonal antibodies to recognize, inhibit, or activate mouse BAFF was investigated. One of them, a mouse IgG1 named Sandy-2, prevented the binding of BAFF to all of its receptors, BAFF receptor, transmembrane activator and calcium modulating ligand interactor, and B cell maturation antigen, at a stoichiometric ratio; blocked the activity of mouse BAFF on a variety of cell-based reporter assays; and antagonized the prosurvival action of BAFF on primary mouse B cells in vitro A single administration of Sandy-2 in mice induced B cell depletion within 2 weeks, down to levels close to those observed in BAFF-deficient mice. This depletion could then be maintained with a chronic treatment. Sandy-2 and a previously described rat IgG1 antibody, 5A8, also formed a pair suitable for the sensitive detection of endogenous circulating BAFF by ELISA or using a homogenous assay. Interestingly, 5A8 and Sandy-5 displayed activities opposite to that of Sandy-2 by stimulating recombinant BAFF in vitro and endogenous BAFF in vivo These tools will prove useful for the detection and functional manipulation of endogenous mouse BAFF and provide an alternative to the widely used BAFF receptor-Fc decoy receptor for the specific depletion of BAFF in mice. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  10. [Development of Holistic Cancer Treatment Centering Cancer Patients - From the Standpoint of Hypoxia and Hedgehog Signaling].

    Science.gov (United States)

    Onishi, Hideya; Ogino, Toshitatsu; Morisaki, Takashi; Katano, Mitsuo

    2017-11-01

    Recently, hypoxia that is one of cancer microenvironments, takes much attention. Because circumstance that we usually perform experiment is 20% O2 condition, it is likely that different signaling pathways may be activated in vivo cancer. We focused Hedgehog(Hh)signaling as one of activated pathways under hypoxia. It has been shown that Hh signaling is activated under hypoxia, followed by inducing malignant phenotypes in pancreatic cancer. Therefore, Hh signaling inhibitor should elicit anti-tumor effect. However, if we consider "whole-person therapy" we should confirm how Hh signaling affects the function of immune cells. In the present study, we describe hypoxia/Hh signaling/functions of cancer cells and immune cells focusing our previous results.

  11. An immunohistochemical study of the expression of the hypoxia markers Glut-1 and Ca-IX in canine sarcomas.

    Science.gov (United States)

    Abbondati, E; Del-Pozo, J; Hoather, T M; Constantino-Casas, F; Dobson, J M

    2013-11-01

    Tumor hypoxia has been associated with increased malignancy, likelihood of metastasis, and increased resistance to radiotherapy and chemotherapy in human medicine. Hypoxia-inducible factor-1 (HIF-1) is a key transcription factor that is induced by tumor hypoxia and regulates the pathways involved in cellular response and adaptation to the hostile tumor microenvironment. HIF-1 induces transcription of different proteins, including Ca-IX and Glut-1, which are considered endogenous markers of chronic hypoxia in solid tumors in humans. In this study, sections from 40 canine sarcomas (20 histiocytic sarcomas and 20 low-grade soft-tissue sarcomas) were immunostained for these markers. Expression of Glut-1 was scored based on percentage of positive staining cells (0 = 50%) and intensity of cellular staining (1 = weak; 2 = strong); Ca-IX was scored based on percentage of positive cells (0 = 30%). Intratumoral microvessel density was measured using CD31 to assess intratumoral neoangiogenesis. Histiocytic sarcomas showed statistically significant higher Glut-1 immunoreactivity and angiogenesis than did low-grade soft-tissue sarcomas. Intratumoral microvessel density in histiocytic sarcomas was positively associated with Glut-1 immunoreactivity score. These findings suggest a potential role of hypoxia in the biology of these tumors and may provide a base for investigation of the potential prognostic use of these markers in naturally occurring canine tumors.

  12. Inhibition of the H3K9 methyltransferase G9A attenuates oncogenicity and activates the hypoxia signaling pathway

    Science.gov (United States)

    Ho, Jolene Caifeng; Abdullah, Lissa Nurrul; Pang, Qing You; Jha, Sudhakar; Chow, Edward Kai-Hua; Yang, Henry; Kato, Hiroyuki; Ueda, Jun

    2017-01-01

    Epigenetic mechanisms play important roles in the regulation of tumorigenesis, and hypoxia-induced epigenetic changes may be critical for the adaptation of cancer cells to the hypoxic microenvironment of solid tumors. Previously, we showed that loss-of-function of the hypoxia-regulated H3K9 methyltransferase G9A attenuates tumor growth. However, the mechanisms by which blockade of G9A leads to a tumor suppressive effect remain poorly understood. We show that G9A is highly expressed in breast cancer and is associated with poor patient prognosis, where it may function as a potent oncogenic driver. In agreement with this, G9A inhibition by the small molecule inhibitor, BIX-01294, leads to increased cell death and impaired cell migration, cell cycle and anchorage-independent growth. Interestingly, whole transcriptome analysis revealed that genes involved in diverse cancer cell functions become hypoxia-responsive upon G9A inhibition. This was accompanied by the upregulation of the hypoxia inducible factors HIF1α and HIF2α during BIX-01294 treatment even in normoxia that may facilitate the tumor suppressive effects of BIX-01294. HIF inhibition was able to reverse some of the transcriptional changes induced by BIX-01294 in hypoxia, indicating that the HIFs may be important drivers of these derepressed target genes. Therefore, we show that G9A is a key mediator of oncogenic processes in breast cancer cells and G9A inhibition by BIX-01294 can successfully attenuate oncogenicity even in hypoxia. PMID:29145444

  13. In vivo characterization of a reporter gene system for imaging hypoxia-induced gene expression

    International Nuclear Information System (INIS)

    Carlin, Sean; Pugachev, Andrei; Sun Xiaorong; Burke, Sean; Claus, Filip; O'Donoghue, Joseph; Ling, C. Clifton; Humm, John L.

    2009-01-01

    Purpose: To characterize a tumor model containing a hypoxia-inducible reporter gene and to demonstrate utility by comparison of reporter gene expression to the uptake and distribution of the hypoxia tracer 18 F-fluoromisonidazole ( 18 F-FMISO). Methods: Three tumors derived from the rat prostate cancer cell line R3327-AT were grown in each of two rats as follows: (1) parental R3327-AT, (2) positive control R3327-AT/PC in which the HSV1-tkeGFP fusion reporter gene was expressed constitutively, (3) R3327-AT/HRE in which the reporter gene was placed under the control of a hypoxia-inducible factor-responsive promoter sequence (HRE). Animals were coadministered a hypoxia-specific marker (pimonidazole) and the reporter gene probe 124 I-2'-fluoro-2'-deoxy-1-β-D-arabinofuranosyl-5-iodouracil ( 124 I-FIAU) 3 h prior to sacrifice. Statistical analysis of the spatial association between 124 I-FIAU uptake and pimonidazole fluorescent staining intensity was then performed on a pixel-by-pixel basis. Utility of this system was demonstrated by assessment of reporter gene expression versus the exogenous hypoxia probe 18 F-FMISO. Two rats, each bearing a single R3327-AT/HRE tumor, were injected with 124 I-FIAU (3 h before sacrifice) and 18 F-FMISO (2 h before sacrifice). Statistical analysis of the spatial association between 18 F-FMISO and 124 I-FIAU on a pixel-by-pixel basis was performed. Results: Correlation coefficients between 124 I-FIAU uptake and pimonidazole staining intensity were: 0.11 in R3327-AT tumors, -0.66 in R3327-AT/PC and 0.76 in R3327-AT/HRE, confirming that only in the R3327-AT/HRE tumor was HSV1-tkeGFP gene expression associated with hypoxia. Correlation coefficients between 18 F-FMISO and 124 I-FIAU uptakes in R3327-AT/HRE tumors were r=0.56, demonstrating good spatial correspondence between the two tracers. Conclusions: We have confirmed hypoxia-specific expression of the HSV1-tkeGFP fusion gene in the R3327-AT/HRE tumor model and demonstrated the utility of

  14. 12TH Biennial International Hypoxia Symposium

    National Research Council Canada - National Science Library

    Roach, Robert

    2001-01-01

    The International Hypoxia Symposia (IHS) meet every other year to bring together international experts from many fields to focus on and discuss the state of the art in normal and pathophysiological responses to hypoxia...

  15. Physiological determinants of human acute hypoxia tolerance.

    Science.gov (United States)

    2013-11-01

    AbstractIntroduction. We investigated possible physiological determinants of variability in hypoxia tolerance in subjects given a 5-minute normobaric exposure to 25,000 ft equivalent. Physiological tolerance to hypoxia was defined as the magnitude of...

  16. Snail/beta-catenin signaling protects breast cancer cells from hypoxia attack

    Energy Technology Data Exchange (ETDEWEB)

    Scherbakov, Alexander M., E-mail: alex.scherbakov@gmail.com [Laboratory of Clinical Biochemistry, Institute of Clinical Oncology, N.N. Blokhin Cancer Research Centre, Kashirskoye sh. 24, Moscow 115478 (Russian Federation); Stefanova, Lidia B.; Sorokin, Danila V.; Semina, Svetlana E. [Laboratory of Molecular Endocrinology, Institute of Carcinogenesis, N.N. Blokhin Cancer Research Centre, Kashirskoye sh. 24, Moscow 115478 (Russian Federation); Berstein, Lev M. [Laboratory of Oncoendocrinology, N.N. Petrov Research Institute of Oncology, St. Petersburg 197758 (Russian Federation); Krasil’nikov, Mikhail A. [Laboratory of Molecular Endocrinology, Institute of Carcinogenesis, N.N. Blokhin Cancer Research Centre, Kashirskoye sh. 24, Moscow 115478 (Russian Federation)

    2013-12-10

    the level of AMPK phosphorylation may be considered as predictors of the tumor sensitivity to anti-angiogenic drugs. - Highlights: • Snail1 protects breast cancer cells from hypoxia. • Protective effect of Snail1 is mediated via β-catenin/HIF-1 pathway. • Snail/β-catenin signaling is negatively controlled by the energy sensor – AMPK. • The failure in AMPK phosphorylation drives cells to the hypoxia-tolerant state.

  17. Hypoxia Induces Internalization of κ-Opioid Receptor.

    Science.gov (United States)

    Xi, Chunhua; Liang, Xuan; Chen, Chunhua; Babazada, Hasan; Li, Tianzuo; Liu, Renyu

    2017-05-01

    It has been demonstrated that κ-opioid receptor agonists can reduce hypoxia-ischemia brain injury in animal models. However, it is unclear how the κ-opioid receptor responds to hypoxia-ischemia. In the current study, the authors used an in vitro model of oxygen-glucose deprivation and reoxygenation to explore how κ-opioid receptors respond to hypoxia and reoxygenation. Mouse neuroblastoma Neuro2A cells were stably transfected with mouse κ-opioid receptor-tdTomato fusion protein or Flag-tagged mouse κ-opioid receptor, divided into several groups (n = 6 to 12), and used to investigate the κ-opioid receptor movement. Observations were performed under normal oxygen, at 30 min to 1 h after oxygen-glucose deprivation and at 1 h after reoxygenation using high-resolution imaging techniques including immunoelectronmicroscopy in the presence and absence of κ-opioid receptor antagonist, dynamin inhibitors, potassium channel blockers, and dopamine receptor inhibitor. Hypoxic conditions caused the κ-opioid receptor to be internalized into the cells. Inhibition of dynamin by Dyngo-4a prevented the receptor internalization. Interestingly, a specific κ-opioid receptor antagonist norbinaltorphimine blocked internalization, suggesting the involvement of activation of a specific κ-opioid receptor. κ-Opioid receptor internalization appears to be reversed by reoxygenation. Quantities of intracellular κ-opioid receptor-associated gold particles as demonstrated by immunoelectron microscopy were increased from 37 to 85% (P internalization. Hypoxia induces reversible κ-opioid receptor internalization, which was inhibited by selective κ-opioid receptor antagonists or dynamin inhibitor, and can be reversed by reoxygenation in neuroblastoma cells, indicating the modulating effects between κ-opioid receptor and hypoxia via κ-opioid receptor activation and the dynamin-dependent mechanism.

  18. Ibuprofen Blunts Ventilatory Acclimatization to Sustained Hypoxia in Humans.

    Directory of Open Access Journals (Sweden)

    Kemal Erdem Basaran

    Full Text Available Ventilatory acclimatization to hypoxia is a time-dependent increase in ventilation and the hypoxic ventilatory response (HVR that involves neural plasticity in both carotid body chemoreceptors and brainstem respiratory centers. The mechanisms of such plasticity are not completely understood but recent animal studies show it can be blocked by administering ibuprofen, a nonsteroidal anti-inflammatory drug, during chronic hypoxia. We tested the hypothesis that ibuprofen would also block the increase in HVR with chronic hypoxia in humans in 15 healthy men and women using a double-blind, placebo controlled, cross-over trial. The isocapnic HVR was measured with standard methods in subjects treated with ibuprofen (400 mg every 8 hrs or placebo for 48 hours at sea level and 48 hours at high altitude (3,800 m. Subjects returned to sea level for at least 30 days prior to repeating the protocol with the opposite treatment. Ibuprofen significantly decreased the HVR after acclimatization to high altitude compared to placebo but it did not affect ventilation or arterial O2 saturation breathing ambient air at high altitude. Hence, compensatory responses prevent hypoventilation with decreased isocapnic ventilatory O2-sensitivity from ibuprofen at this altitude. The effect of ibuprofen to decrease the HVR in humans provides the first experimental evidence that a signaling mechanism described for ventilatory acclimatization to hypoxia in animal models also occurs in people. This establishes a foundation for the future experiments to test the potential role of different mechanisms for neural plasticity and ventilatory acclimatization in humans with chronic hypoxemia from lung disease.

  19. Hypoxia: Exposure Time Until Significant Performance Effects

    Science.gov (United States)

    2016-03-07

    1994). Acute hypoxia fails to influence two aspects of short-term memory : implications for the source of cognitive deficits. Aviation, Space...Naval Medical Research Unit Dayton HYPOXIA : EXPOSURE TIME UNTIL SIGNIFICANT PERFORMANCE EFFECTS PHILLIPS, J.P., DRUMMOND, L.A...Andrews, CAPT, MSC, USN Commanding Officer i 1 ARTICLE TYPE: Research Article TITLE: Hypoxia : Exposure Time Until Significant Performance

  20. Teleosts in hypoxia : Aspects of anaerobic metabolism

    NARCIS (Netherlands)

    Van den Thillart, G.; van Waarde, Aren

    1985-01-01

    Moderate hypoxia can be tolerated by many fish species, while only some species survive severe hypoxia or anoxia. Hypoxia usually activates anaerobic glycolysis, which may be temporary when the animals are able to improve their oxygen extraction capacity. Switching over to aerobic metabolism allows

  1. Comparing the DN4 tool with the IASP grading system for chronic neuropathic pain screening after breast tumor resection with and without paravertebral blocks: a prospective 6-month validation study.

    Science.gov (United States)

    Abdallah, Faraj W; Morgan, Pamela J; Cil, Tulin; Escallon, Jaime M; Semple, John L; Chan, Vincent W

    2015-04-01

    Investigating protective strategies against chronic neuropathic pain (CNP) after breast cancer surgery entails using valid screening tools. The DN4 (Douleur Neuropathique en 4 questions) is 1 tool that offers important research advantages. This prospective 6-month follow-up study seeks to validate the DN4 and assess its responsiveness in screening for CNP that satisfies the International Association for the Study of Pain (IASP) definition and fulfills its grading system criteria after breast tumor resection with and without paravertebral blocks (PVBs). We randomized 66 females to standardized general anesthesia and sham subcutaneous injections, or PVB and total intravenous anesthesia. The 6-month CNP risk was assessed using the IASP grading system and the DN4 screening tools. We evaluated the DN4 sensitivity, specificity, and responsiveness in capturing the impact of PVB on the CNP risk relative to the IASP grading system. Data from 64 patients showed similar demographic characteristics in both groups. Twenty patients in both groups met the grading system CNP criteria; among these, 18 patients also met the DN4 CNP criteria. Furthermore, 15 patients in both groups did not meet the grading system CNP criteria; among these, 9 patients also did not meet the DN4 CNP criteria. Therefore, the sensitivity and specificity of the DN4 were estimated at 90% and 60%, respectively. Both screening tools suggested that PVB reduced the 6-month CNP risk. Our results suggest that the DN4 can reliably identify CNP at 6 months after breast tumor resection and detect the preincisional PVB effect on the risk of developing such pain.

  2. Coastal hypoxia responses to remediation

    Science.gov (United States)

    Kemp, W. M.; Testa, J. M.; Conley, D. J.; Gilbert, D.; Hagy, J. D.

    2009-07-01

    The incidence and intensity of hypoxic waters in coastal aquatic ecosystems has been expanding in recent decades coincident with eutrophication of the coastal zone. Because of the negative effects hypoxia has on many organisms, extensive efforts have been made to reduce the size and duration of hypoxia in many coastal waters. Although it has been broadly assumed that reductions in nutrient loading rates would reverse eutrophication and consequently, hypoxia, recent analyses of historical data from European and North American coastal systems suggest little evidence for simple linear response trajectories. We review existing data, analyses, and models that relate variations in the extent and intensity of hypoxia to changes in loading rates for inorganic nutrients and labile organic matter. We also assess existing knowledge of physical and ecological factors regulating oxygen in coastal marine waters and examine a broad range of examples where hypoxia responses to reductions in nutrient (or organic matter) inputs have been documented. Of the 22 systems identified where concurrent time series of loading and O2 were available, half displayed relatively clear and direct recoveries following remediation. We explored in detail 5 well-studied systems that have exhibited complex, non-linear responses to loading, including apparent "regime shifts." A summary of these analyses suggests that O2 conditions improved rapidly and linearly in systems where remediation focused on organic inputs from sewage plants, which were the primary drivers of hypoxia. In larger more open systems where diffuse nutrient loads are more important in fueling O2 depletion and where climatic influences are pronounced, responses to remediation tend to follow non-linear trends that may include hysteresis and time-lags. Improved understanding of hypoxia remediation requires that future studies use comparative approaches and consider multiple regulating factors including: (1) the dominant temporal scales

  3. Down-titration and discontinuation strategies of tumor necrosis factor-blocking agents for rheumatoid arthritis in patients with low disease activity.

    Science.gov (United States)

    van Herwaarden, Noortje; den Broeder, Alfons A; Jacobs, Wilco; van der Maas, Aatke; Bijlsma, Johannes W J; van Vollenhoven, Ronald F; van den Bemt, Bart J F

    2014-09-29

    Anti-tumor necrosis factor (TNF) agents are effective in treating patients with rheumatoid arthritis (RA), but they are associated with (dose-dependent) adverse effects and high costs. To prevent overtreatment, several trials have assessed the effectiveness of down-titration compared with continuation of the standard dose. To evaluate the benefits and harms of down-titration (dose reduction, discontinuation or disease activity guided dose tapering) of anti-TNF agents (adalimumab, certolizumab pegol, etanercept, golimumab, infliximab) on disease activity, functioning, costs, safety and radiographic damage compared with usual care in patients with RA and low disease activity. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), Issue 8, 2013; Ovid MEDLINE (1946 to 8 September 2013); EMBASE (1947 to 8 September 2013); Science Citation Index (Web of Science); and conference proceedings of the American College of Rheumatology (2005 to 2012) and European League against Rheumatism (2005 to 2013). We contacted authors of the seven included studies to ask for additional information on their study; five responded. Randomised controlled trials (RCTs) and controlled clinical trials (CCTs) comparing down-titration (dose reduction, discontinuation, disease activity-guided dose tapering) of anti-TNF agents (adalimumab, certolizumab pegol, etanercept, golimumab, infliximab) to usual care/no down-titration in patients with RA and a low disease activity state. Two review authors independently selected studies, assessed risk of bias and extracted data. Six RCTs and one CCT (total 1203 participants), reporting anti-TNF down-titration, were included. Three studies (559 participants) reported anti-TNF dose reduction compared with anti-TNF continuation. Five studies (732 participants) reported anti-TNF discontinuation compared with anti-TNF continuation (two studies assessed both anti-TNF discontinuation and dose reduction), and one study assessed disease activity

  4. RNAi Knockdown of Hypoxia-Inducible Factor-1α Decreased the Proliferation, Migration, and Invasion of Hypoxic Hepatocellular Carcinoma Cells.

    Science.gov (United States)

    Chen, ChengShi; Liu, Rong; Wang, JianHua; Yan, ZhiPing; Qian, Sheng; Zhang, Wei

    2015-04-01

    The obstruction of hepatic arterial blood flow results in tumor tissue hypoxia and elevated expression of hypoxia-inducible factor-1alpha (HIF-1α). Our study evaluated whether lentivirus-mediated short interference RNA against HIF-1α inhibits proliferation, invasion, and migration of hepatocellular carcinoma (HCC) cells under hypoxia. RNA interference knockdown of HIF-1α was achieved by HIF-1α-directed lentiviral shRNA, in a rat HCC cell line cultured under hypoxia condition for varying length of times. The expression levels of HIF-1α and vascular endothelial growth factor were examined using reverse transcription polymerase chain reaction and western blot analyses. Cell proliferation, migration, and invasion were measured by cell viability, transwell migration, and invasion assays, respectively. Inhibition of HIF-1α expression by shRNA suppressed vascular endothelial growth factor mRNA and protein levels under both normoxia and hypoxia. It also suppressed cell migration and invasion, which were enhanced under hypoxic conditions. RNAi knockdown of HIF-1α further suppressed hypoxia-mediated inhibition of the cell proliferation. These data suggest that shRNA of HIF-1α could antagonize the hypoxia-mediated increase in hepatic cancer cell migration and invasion, and synergize with hypoxia to inhibit the cell proliferation in HCC cells.

  5. Regulation of matrix stiffness on the epithelial-mesenchymal transition of breast cancer cells under hypoxia environment

    Science.gov (United States)

    Lv, Yonggang; Chen, Can; Zhao, Boyuan; Zhang, Xiaomei

    2017-06-01

    Substrate stiffness and hypoxia are associated with tumor development and progression, respectively. However, the synergy of them on the biological behavior of human breast cancer cell is still largely unknown. This study explored how substrate stiffness regulates the cell phenotype, viability, and epithelial-mesenchymal transition (EMT) of human breast cancer cells MCF-7 under hypoxia (1% O2). TRITC-phalloidin staining showed that MCF-7 cells transformed from round to irregular polygon with stiffness increase either in normoxia or hypoxia. While being accompanied with the upward tendency from a 0.5- to a 20-kPa substrate, the percentage of cell apoptosis was significantly higher in hypoxia than that in normoxia, especially on the 20-kPa substrate. Additionally, it was hypoxia, but not normoxia, that promoted the EMT of MCF-7 by upregulating hypoxia-inducible factor-1α (HIF-1α), vimentin, Snail 1, and matrix metalloproteinase 2 (MMP 2) and 9 (MMP 9), and downregulating E-cadherin simultaneously regardless of the change of substrate stiffness. In summary, this study discovered that hypoxia and stiffer substrate (20 kPa) could synergistically induce phenotype change, apoptosis, and EMT of MCF-7 cells. Results of this study have an important significance on further exploring the synergistic effect of stiffness and hypoxia on the EMT of breast cancer cells and its molecular mechanism.

  6. Celiac ganglia block

    Energy Technology Data Exchange (ETDEWEB)

    Akinci, Devrim [Department of Radiology, Hacettepe University School of Medicine, Sihhiye, 06100 Ankara (Turkey); Akhan, Okan [Department of Radiology, Hacettepe University School of Medicine, Sihhiye, 06100 Ankara (Turkey)]. E-mail: oakhan@hacettepe.edu.tr

    2005-09-01

    Pain occurs frequently in patients with advanced cancers. Tumors originating from upper abdominal viscera such as pancreas, stomach, duodenum, proximal small bowel, liver and biliary tract and from compressing enlarged lymph nodes can cause severe abdominal pain, which do not respond satisfactorily to medical treatment or radiotherapy. Percutaneous celiac ganglia block (CGB) can be performed with high success and low complication rates under imaging guidance to obtain pain relief in patients with upper abdominal malignancies. A significant relationship between pain relief and degree of tumoral celiac ganglia invasion according to CT features was described in the literature. Performing the procedure in the early grades of celiac ganglia invasion on CT can increase the effectiveness of the CGB, which is contrary to World Health Organization criteria stating that CGB must be performed in patients with advanced stage cancer. CGB may also be effectively performed in patients with chronic pancreatitis for pain palliation.

  7. Celiac ganglia block

    International Nuclear Information System (INIS)

    Akinci, Devrim; Akhan, Okan

    2005-01-01

    Pain occurs frequently in patients with advanced cancers. Tumors originating from upper abdominal viscera such as pancreas, stomach, duodenum, proximal small bowel, liver and biliary tract and from compressing enlarged lymph nodes can cause severe abdominal pain, which do not respond satisfactorily to medical treatment or radiotherapy. Percutaneous celiac ganglia block (CGB) can be performed with high success and low complication rates under imaging guidance to obtain pain relief in patients with upper abdominal malignancies. A significant relationship between pain relief and degree of tumoral celiac ganglia invasion according to CT features was described in the literature. Performing the procedure in the early grades of celiac ganglia invasion on CT can increase the effectiveness of the CGB, which is contrary to World Health Organization criteria stating that CGB must be performed in patients with advanced stage cancer. CGB may also be effectively performed in patients with chronic pancreatitis for pain palliation

  8. Radiosensitization by the histone deacetylase inhibitor vorinostat under hypoxia and with capecitabine in experimental colorectal carcinoma

    International Nuclear Information System (INIS)

    Saelen, Marie Grøn; Ree, Anne Hansen; Kristian, Alexandr; Fleten, Karianne Giller; Furre, Torbjørn; Hektoen, Helga Helseth; Flatmark, Kjersti

    2012-01-01

    The histone deacetylase inhibitor vorinostat is a candidate radiosensitizer in locally advanced rectal cancer (LARC). Radiosensitivity is critically influenced by hypoxia; hence, it is important to evaluate the efficacy of potential radiosensitizers under variable tissue oxygenation. Since fluoropyrimidine-based chemoradiotherapy (CRT) is the only clinically validated regimen in LARC, efficacy in combination with this established regimen should be assessed in preclinical models before a candidate drug enters clinical trials. Radiosensitization by vorinostat under hypoxia was studied in four colorectal carcinoma cell lines and in one colorectal carcinoma xenograft model by analysis of clonogenic survival and tumor growth delay, respectively. Radiosensitizing effects of vorinostat in combination with capecitabine were assessed by evaluation of tumor growth delay in two colorectal carcinoma xenografts models. Under hypoxia, radiosensitization by vorinostat was demonstrated in vitro in terms of decreased clonogenicity and in vivo as inhibition of tumor growth. Adding vorinostat to capecitabine-based CRT increased radiosensitivity of xenografts in terms of inhibited tumor growth. Vorinostat sensitized colorectal carcinoma cells to radiation under hypoxia in vitro and in vivo and improved therapeutic efficacy in combination with capecitabine-based CRT in vivo. The results encourage implementation of vorinostat into CRT in LARC trials

  9. Hypoxia-Inducible Factor-1α in carcinogenesis and progression of breast cancer

    NARCIS (Netherlands)

    Bos, R.

    2004-01-01

    This thesis is primarily focused on the previously hardly explored role of HIF-1 in breast cancer. HIF-1 is a transcription factor induced by hypoxia, but also by some oncogenes, tumor suppressor genes and growth factors. Activated HIF-1 can induce angiogenesis, glycolysis, erythropoiesis, and other

  10. Radiosensitization by the histone deacetylase inhibitor vorinostat under hypoxia and with capecitabine in experimental colorectal carcinoma.

    Science.gov (United States)

    Saelen, Marie Grøn; Ree, Anne Hansen; Kristian, Alexandr; Fleten, Karianne Giller; Furre, Torbjørn; Hektoen, Helga Helseth; Flatmark, Kjersti

    2012-09-27

    The histone deacetylase inhibitor vorinostat is a candidate radiosensitizer in locally advanced rectal cancer (LARC). Radiosensitivity is critically influenced by hypoxia; hence, it is important to evaluate the efficacy of potential radiosensitizers under variable tissue oxygenation. Since fluoropyrimidine-based chemoradiotherapy (CRT) is the only clinically validated regimen in LARC, efficacy in combination with this established regimen should be assessed in preclinical models before a candidate drug enters clinical trials. Radiosensitization by vorinostat under hypoxia was studied in four colorectal carcinoma cell lines and in one colorectal carcinoma xenograft model by analysis of clonogenic survival and tumor growth delay, respectively. Radiosensitizing effects of vorinostat in combination with capecitabine were assessed by evaluation of tumor growth delay in two colorectal carcinoma xenografts models. Under hypoxia, radiosensitization by vorinostat was demonstrated in vitro in terms of decreased clonogenicity and in vivo as inhibition of tumor growth. Adding vorinostat to capecitabine-based CRT increased radiosensitivity of xenografts in terms of inhibited tumor growth. Vorinostat sensitized colorectal carcinoma cells to radiation under hypoxia in vitro and in vivo and improved therapeutic efficacy in combination with capecitabine-based CRT in vivo. The results encourage implementation of vorinostat into CRT in LARC trials.

  11. Radiosensitization by the histone deacetylase inhibitor vorinostat under hypoxia and with capecitabine in experimental colorectal carcinoma

    Directory of Open Access Journals (Sweden)

    Saelen Marie

    2012-09-01

    Full Text Available Abstract Background The histone deacetylase inhibitor vorinostat is a candidate radiosensitizer in locally advanced rectal cancer (LARC. Radiosensitivity is critically influenced by hypoxia; hence, it is important to evaluate the efficacy of potential radiosensitizers under variable tissue oxygenation. Since fluoropyrimidine-based chemoradiotherapy (CRT is the only clinically validated regimen in LARC, efficacy in combination with this established regimen should be assessed in preclinical models before a candidate drug enters clinical trials. Methods Radiosensitization by vorinostat under hypoxia was studied in four colorectal carcinoma cell lines and in one colorectal carcinoma xenograft model by analysis of clonogenic survival and tumor growth delay, respectively. Radiosensitizing effects of vorinostat in combination with capecitabine were assessed by evaluation of tumor growth delay in two colorectal carcinoma xenografts models. Results Under hypoxia, radiosensitization by vorinostat was demonstrated in vitro in terms of decreased clonogenicity and in vivo as inhibition of tumor growth. Adding vorinostat to capecitabine-based CRT increased radiosensitivity of xenografts in terms of inhibited tumor growth. Conclusions Vorinostat sensitized colorectal carcinoma cells to radiation under hypoxia in vitro and in vivo and improved therapeutic efficacy in combination with capecitabine-based CRT in vivo. The results encourage implementation of vorinostat into CRT in LARC trials.

  12. Emerging evidence of the physiological role of hypoxia in mammary development and lactation

    Science.gov (United States)

    2014-01-01

    Hypoxia is a physiological or pathological condition of a deficiency of oxygen supply in the body as a whole or within a tissue. During hypoxia, tissues undergo a series of physiological responses to defend themselves against a low oxygen supply, including increased angiogenesis, erythropoiesis, and glucose uptake. The effects of hypoxia are mainly mediated by hypoxia-inducible factor 1 (HIF-1), which is a heterodimeric transcription factor consisting of α and β subunits. HIF-1β is constantly expressed, whereas HIF-1α is degraded under normal oxygen conditions. Hypoxia stabilizes HIF-1α and the HIF complex, and HIF then translocates into the nucleus to initiate the expression of target genes. Hypoxia has been extensively studied for its role in promoting tumor progression, and emerging evidence also indicates that hypoxia may play important roles in physiological processes, including mammary development and lactation. The mammary gland exhibits an increasing metabolic rate from pregnancy to lactation to support mammary growth, lactogenesis, and lactation. This process requires increasing amounts of oxygen consumption and results in localized chronic hypoxia as confirmed by the binding of the hypoxia marker pimonidazole HCl in mouse mammary gland. We hypothesized that this hypoxic condition promotes mammary development and lactation, a hypothesis that is supported by the following several lines of evidence: i) Mice with an HIF-1α deletion selective for the mammary gland have impaired mammary differentiation and lipid secretion, resulting in lactation failure and striking changes in milk compositions; ii) We recently observed that hypoxia significantly induces HIF-1α-dependent glucose uptake and GLUT1 expression in mammary epithelial cells, which may be responsible for the dramatic increases in glucose uptake and GLUT1 expression in the mammary gland during the transition period from late pregnancy to early lactation; and iii) Hypoxia and HIF-1α increase the

  13. Plasma volume in acute hypoxia

    DEFF Research Database (Denmark)

    Poulsen, T D; Klausen, T; Richalet, J P

    1998-01-01

    Exposure to acute hypoxia is associated with changes in body fluid homeostasis and plasma volume (PV). This study compared a dye dilution technique using Evans' blue (PV[Evans']) with a carbon monoxide (CO) rebreathing method (PV[CO]) for measurements of PV in ten normal subjects at sea level...

  14. Hypoxia and development : Air conditional

    NARCIS (Netherlands)

    Voesenek, L.A.C.J.; Bailey-Serres, Julia

    Hypoxia has long been studied in relation to anaerobic metabolism. It has now been shown to control development, acting as a cue to maintain the seedling’s protective apical hook and a trigger of developmental decisions both before and after the plantlet emerges from the soil into the light.

  15. [Inhibitory effect of taurine in hypoxia-induced rat pulmonary artery smooth muscle cell proliferation and signal transduction mechanism].

    Science.gov (United States)

    Zhang, Xiao-Dan; Sun, Peng; Zhu, Da-Ling; Xie, Nan

    2014-05-01

    To discuss the effect of taurine (Tau) on the proliferation of hypoxia-induced pulmonary artery smooth muscle cells (PASMCs), and study whether the extracellular signal-regulated kinase 1/2 (ERK1/2) signal pathway participated in the Tau-inhibited PASMC proliferation process and the possible molecular mechanism. The primary culture was performed for PASMCs in rats. The second to fifth generations were adopted for the experiment. The Tau concentration was 80 mmol x L(-1). The concentration of ERK1/2 blocker (PD98059) was 50 micromol x L(-1). The drug administration time was 24 h. The effect of Tau on the PASMC proliferation was detected by MTT assay, immunofluorescence staining method and western blot under different conditions. The PASMCs were growing were divided into four groups: the normoxia group, the normoxia + Tau group, the hypoxia group and the hypoxia + Tau group. The Western blot was adopted to detect whether the ERK1/2 signal pathway participated in the Tau-inhibited PASMC proliferation process. Subsequently, the PASMCs were divided into five groups: the normoxia group, the hypoxia group, the hypoxia + Tau group, the hypoxia + Tau + PD98059 group and the hypoxia + PD98059 group. Hypoxia could induce the PASMC proliferation. Under the conditions of normoxia, Tau had no effect on the PASMC proliferation. Under the conditions of normoxia and hypoxia, Tau had no effect on the expression of the tumor necrosis factor-alpha (TNF-alpha) among PASMCs. Tau could reverse the expression up-regulation of hypoxia-induced proliferative cell nuclear antigen (PCNA) (P effect on the expression of phosphoryl extracellular signal-regulated kinase 1/2 (p-ERK1/2). Hypoxia could up-regulate the p-ERK1/2 expression (P < 0.01). Tau could reverse the up-regulation of the hypoxia-induced p-ERK1/2 expression(P < 0.01). Both PD98059 and Tau could inhibit the up-regulated expressions of PCNA, Cyclin A and p-ERK1/2. According to the comparison between the single addition of Tau and PD

  16. Enhanceosomes as integrators of hypoxia inducible factor (HIF) and other transcription factors in the hypoxic transcriptional response.

    Science.gov (United States)

    Pawlus, Matthew R; Hu, Cheng-Jun

    2013-09-01

    Hypoxia is a prevalent attribute of the solid tumor microenvironment that promotes the expression of genes through posttranslational modifications and stabilization of alpha subunits (HIF1α and HIF2α) of hypoxia-inducible factors (HIFs). Despite significant similarities, HIF1 (HIF1α/ARNT) and HIF2 (HIF2α/ARNT) activate common as well as unique target genes and exhibit different functions in cancer biology. More surprisingly, accumulating data indicates that the HIF1- and/or HIF2-mediated hypoxia responses can be oncogenic as well as tumor suppressive. While the role of HIF in the hypoxia response is well established, recent data support the concept that HIF is necessary, but not sufficient for the hypoxic response. Other transcription factors that are activated by hypoxia are also required for the HIF-mediated hypoxia response. HIFs, other transcription factors, co-factors and RNA poll II recruited by HIF and other transcription factors form multifactorial enhanceosome complexes on the promoters of HIF target genes to activate hypoxia inducible genes. Importantly, HIF1 or HIF2 requires distinct partners in activating HIF1 or HIF2 target genes. Because HIF enhanceosome formation is required for the gene activation and distinct functions of HIF1 and HIF2 in tumor biology, disruption of the HIF1 or HIF2 specific enhanceosome complex may prove to be a beneficial strategy in tumor treatment in which tumor growth is specifically dependent upon HIF1 or HIF2 activity. Copyright © 2013 Elsevier Inc. All rights reserved.

  17. Dependence of FDG uptake on tumor microenvironment

    International Nuclear Information System (INIS)

    Pugachev, Andrei; Ruan, Shutian; Carlin, Sean; Larson, Steven M.; Campa, Jose; Ling, C. Clifton; Humm, John L.

    2005-01-01

    Purpose: To investigate the factors affecting the 18 F-fluorodeoxyglucose ( 18 F-FDG) uptake in tumors at a microscopic level, by correlating it with tumor hypoxia, cellular proliferation, and blood perfusion. Methods and Materials: Nude mice bearing Dunning prostate tumors (R3327-AT) were injected with 18 F-FDG and pimonidazole, bromodeoxyuridine, and, 1 min before sacrifice, with Hoechst 33342. Selected tumor sections were imaged by phosphor plate autoradiography, while adjacent sections were used to obtain the images of the spatial distribution of Hoechst 33342, pimonidazole, and bromodeoxyuridine. The images were co-registered and analyzed on a pixel-by-pixel basis. Results: Statistical analysis of the data obtained from these tumors demonstrated that 18 F-FDG uptake was positively correlated with pimonidazole staining intensity in each data set studied. Correlation of FDG uptake with bromodeoxyuridine staining intensity was always negative. In addition, FDG uptake was always negatively correlated with the staining intensity of Hoechst 33342. Conclusions: For the Dunning prostate tumors studied, FDG uptake was always positively correlated with hypoxia and negatively correlated with both cellular proliferation and blood flow. Therefore, for the tumor model studied, higher FDG uptake is indicative of tumor hypoxia, but neither blood flow nor cellular proliferation

  18. Evaluation of the "steal" phenomenon on the efficacy of hypoxia activated prodrug TH-302 in pancreatic cancer.

    Directory of Open Access Journals (Sweden)

    Kate M Bailey

    Full Text Available Pancreatic ductal adenocarcinomas are desmoplastic and hypoxic, both of which are associated with poor prognosis. Hypoxia-activated prodrugs (HAPs are specifically activated in hypoxic environments to release cytotoxic or cytostatic effectors. TH-302 is a HAP that is currently being evaluated in a Phase III clinical trial in pancreatic cancer. Using animal models, we show that tumor hypoxia can be exacerbated using a vasodilator, hydralazine, improving TH-302 efficacy. Hydralazine reduces tumor blood flow through the "steal" phenomenon, in which atonal immature tumor vasculature fails to dilate in coordination with normal vasculature. We show that MIA PaCa-2 tumors exhibit a "steal" effect in response to hydralazine, resulting in decreased tumor blood flow and subsequent tumor pH reduction. The effect is not observed in SU.86.86 tumors with mature tumor vasculature, as measured by CD31 and smooth muscle actin (SMA immunohistochemistry staining. Combination therapy of hydralazine and TH-302 resulted in a reduction in MIA PaCa-2 tumor volume growth after 18 days of treatment. These studies support a combination mechanism of action for TH-302 with a vasodilator that transiently increases tumor hypoxia.

  19. Targeted expression of heme oxygenase-1 prevents the pulmonary inflammatory and vascular responses to hypoxia

    Science.gov (United States)

    Minamino, Tohru; Christou, Helen; Hsieh, Chung-Ming; Liu, Yuxiang; Dhawan, Vijender; Abraham, Nader G.; Perrella, Mark A.; Mitsialis, S. Alex; Kourembanas, Stella

    2001-07-01

    Chronic hypoxia causes pulmonary hypertension with smooth muscle cell proliferation and matrix deposition in the wall of the pulmonary arterioles. We demonstrate here that hypoxia also induces a pronounced inflammation in the lung before the structural changes of the vessel wall. The proinflammatory action of hypoxia is mediated by the induction of distinct cytokines and chemokines and is independent of tumor necrosis factor- signaling. We have previously proposed a crucial role for heme oxygenase-1 (HO-1) in protecting cardiomyocytes from hypoxic stress, and potent anti-inflammatory properties of HO-1 have been reported in models of tissue injury. We thus established transgenic mice that constitutively express HO-1 in the lung and exposed them to chronic hypoxia. HO-1 transgenic mice were protected from the development of both pulmonary inflammation as well as hypertension and vessel wall hypertrophy induced by hypoxia. Significantly, the hypoxic induction of proinflammatory cytokines and chemokines was suppressed in HO-1 transgenic mice. Our findings suggest an important protective function of enzymatic products of HO-1 activity as inhibitors of hypoxia-induced vasoconstrictive and proinflammatory pathways.

  20. Nitric oxide signaling in hypoxia.

    Science.gov (United States)

    Ho, J J David; Man, H S Jeffrey; Marsden, Philip A

    2012-03-01

    Endothelial-derived nitric oxide (NO) is classically viewed as a regulator of vasomotor tone. NO plays an important role in regulating O(2) delivery through paracrine control of vasomotor tone locally and cardiovascular and respiratory responses centrally. Very soon after the cloning and functional characterization of the endothelial nitric oxide synthase (eNOS), studies on the interaction between O(2) and NO made the paradoxical finding that hypoxia led to decreases in eNOS expression and function. Why would decreases in O(2) content in tissues elicit a loss of a potent endothelial-derived vasodilator? We now know that restricting our view of NO as a regulator of vasomotor tone or blood pressure limited deeper levels of mechanistic insight. Exciting new studies indicate that functional interactions between NO and O(2) exhibit profound complexity and are relevant to diseases states, especially those associated with hypoxia in tissues. NOS isoforms catalytically require O(2). Hypoxia regulates steady-state expression of the mRNA and protein abundance of the NOS enzymes. Animals genetically deficient in NOS isoforms have perturbations in their ability to adapt to changes in O(2) supply or demand. Most interestingly, the intracellular pathways for O(2) sensing that evolved to ensure an appropriate balance of O(2) delivery and utilization intersect with NO signaling networks. Recent studies demonstrate that hypoxia-inducible factor (HIF) stabilization and transcriptional activity is achieved through two parallel pathways: (1) a decrease in O(2)-dependent prolyl hydroxylation of HIF and (2) S-nitrosylation of HIF pathway components. Recent findings support a role for S-nitrosothiols as hypoxia-mimetics in certain biological and/or disease settings, such as living at high altitude, exposure to small molecules that can bind NO, or anemia.

  1. Ubiquitination and regulation of AURKA identifies a hypoxia-independent E3 ligase activity of VHL.

    Science.gov (United States)

    Hasanov, E; Chen, G; Chowdhury, P; Weldon, J; Ding, Z; Jonasch, E; Sen, S; Walker, C L; Dere, R

    2017-06-15

    The hypoxia-regulated tumor-suppressor von Hippel-Lindau (VHL) is an E3 ligase that recognizes its substrates as part of an oxygen-dependent prolyl hydroxylase (PHD) reaction, with hypoxia-inducible factor α (HIFα) being its most notable substrate. Here we report that VHL has an equally important function distinct from its hypoxia-regulated activity. We find that Aurora kinase A (AURKA) is a novel, hypoxia-independent target for VHL ubiquitination. In contrast to its hypoxia-regulated activity, VHL mono-, rather than poly-ubiquitinates AURKA, in a PHD-independent reaction targeting AURKA for degradation in quiescent cells, where degradation of AURKA is required to maintain the primary cilium. Tumor-associated variants of VHL differentiate between these two functions, as a pathogenic VHL mutant that retains intrinsic ability to ubiquitinate HIFα is unable to ubiquitinate AURKA. Together, these data identify VHL as an E3 ligase with important cellular functions under both normoxic and hypoxic conditions.

  2. Dormancy of cancer cells with suppression of AKT activity contributes to survival in chronic hypoxia.

    Directory of Open Access Journals (Sweden)

    Hiroko Endo

    Full Text Available A hypoxic microenvironment in tumors has been recognized as a cause of malignancy or resistance to various cancer therapies. In contrast to recent progress in understanding the acute response of cancer cells to hypoxia, the characteristics of tumor cells in chronic hypoxia remain elusive. We have identified a pancreatic cancer cell line, AsPC-1, that is exceptionally able to survive for weeks under 1% oxygen conditions while most tested cancer cell lines die after only some days under these conditions. In chronic hypoxia, AsPC-1 cells entered a state of dormancy characterized by no proliferation, no death, and metabolic suppression. They reversibly switched to active status after being placed again in optimal culture conditions. ATP turnover, an indicator of energy demand, was markedly decreased and accompanied by reduced AKT phosphorylation. Forced activation of AKT resulted in increased ATP turnover and massive cell death in vitro and a decreased number of dormant cells in vivo. In contrast to most cancer cell lines, primary-cultured colorectal cancer cells easily entered the dormant status with AKT suppression under hypoxia combined with growth factor-depleted conditions. Primary colorectal cancer cells in dormancy were resistant to chemotherapy. Thus, the ability to survive in a deteriorated microenvironment by entering into dormancy under chronic hypoxia might be a common property among cancer cells. Targeting the regulatory mechanism inducing this dormant status could provide a new strategy for treating cancer.

  3. Synchrotron microbeam radiation therapy induces hypoxia in intracerebral gliosarcoma but not in the normal brain

    International Nuclear Information System (INIS)

    Bouchet, Audrey; Lemasson, Benjamin; Christen, Thomas; Potez, Marine; Rome, Claire; Coquery, Nicolas; Le Clec’h, Céline; Moisan, Anaick; Bräuer-Krisch, Elke; Leduc, Géraldine; Rémy, Chantal; Laissue, Jean A.; Barbier, Emmanuel L.; Brun, Emmanuel; Serduc, Raphaël

    2013-01-01

    Purpose: Synchrotron microbeam radiation therapy (MRT) is an innovative irradiation modality based on spatial fractionation of a high-dose X-ray beam into lattices of microbeams. The increase in lifespan of brain tumor-bearing rats is associated with vascular damage but the physiological consequences of MRT on blood vessels have not been described. In this manuscript, we evaluate the oxygenation changes induced by MRT in an intracerebral 9L gliosarcoma model. Methods: Tissue responses to MRT (two orthogonal arrays (2 × 400 Gy)) were studied using magnetic resonance-based measurements of local blood oxygen saturation (MR S O 2 ) and quantitative immunohistology of RECA-1, Type-IV collagen and GLUT-1, marker of hypoxia. Results: In tumors, MR S O 2 decreased by a factor of 2 in tumor between day 8 and day 45 after MRT. This correlated with tumor vascular remodeling, i.e. decrease in vessel density, increases in half-vessel distances (×5) and GLUT-1 immunoreactivity. Conversely, MRT did not change normal brain MR S O 2 , although vessel inter-distances increased slightly. Conclusion: We provide new evidence for the differential effect of MRT on tumor vasculature, an effect that leads to tumor hypoxia. As hypothesized formerly, the vasculature of the normal brain exposed to MRT remains sufficiently perfused to prevent any hypoxia

  4. Molecular imaging using Cu-ATSM and FDG in solid canine tumors

    DEFF Research Database (Denmark)

    Hansen, Anders Elias

    the potential of implementing canine cancer patients in translational research on tumor hypoxia. 2) Non- invasively evaluate the hypoxia positron emission tomography (PET) tracer 64 Copper(II)diacetyl-bis(N 4 -methylthiosemicarbazone) ( 64 Cu-ATSM), including the comparison to non-invasive measures of tumor...... glycolysis and blood perfu- sion. 3) To compare tumor uptake of 64 Cu-ATSM and [ 18 F]fluoro-D-glucose ( 18 FDG) (glycolytic activity) to pimonidazole (immunological hypoxia marker) immunohistochemistry. 4) To investigate 18 FDG PET as a diagnostic modality in canine cancer patients. The thesis contains...

  5. Approximate Simulation of Acute Hypobaric Hypoxia with Normobaric Hypoxia

    Science.gov (United States)

    Conkin, J.; Wessel, J. H., III

    2011-01-01

    INTRODUCTION. Some manufacturers of reduced oxygen (O2) breathing devices claim a comparable hypobaric hypoxia (HH) training experience by providing F(sub I) O2 pO2) of the target altitude. METHODS. Literature from investigators and manufacturers indicate that these devices may not properly account for the 47 mmHg of water vapor partial pressure that reduces the inspired partial pressure of O2 (P(sub I) O2). Nor do they account for the complex reality of alveolar gas composition as defined by the Alveolar Gas Equation. In essence, by providing iso-pO2 conditions for normobaric hypoxia (NH) as for HH exposures the devices ignore P(sub A)O2 and P(sub A)CO2 as more direct agents to induce signs and symptoms of hypoxia during acute training exposures. RESULTS. There is not a sufficient integrated physiological understanding of the determinants of P(sub A)O2 and P(sub A)CO2 under acute NH and HH given the same hypoxic pO2 to claim a device that provides isohypoxia. Isohypoxia is defined as the same distribution of hypoxia signs and symptoms under any circumstances of equivalent hypoxic dose, and hypoxic pO2 is an incomplete hypoxic dose. Some devices that claim an equivalent HH experience under NH conditions significantly overestimate the HH condition, especially when simulating altitudes above 10,000 feet (3,048 m). CONCLUSIONS. At best, the claim should be that the devices provide an approximate HH experience since they only duplicate the ambient pO2 at sea level as at altitude (iso-pO2 machines). An approach to reduce the overestimation is to at least provide machines that create the same P(sub I)O2 (iso-P(sub I)O2 machines) conditions at sea level as at the target altitude, a simple software upgrade.

  6. Glioblastoma: a pathogenic crosstalk between tumor cells and pericytes.

    Directory of Open Access Journals (Sweden)

    Elisabetta M Caspani

    Full Text Available Cancers likely originate in progenitor zones containing stem cells and perivascular stromal cells. Much evidence suggests stromal cells play a central role in tumor initiation and progression. Brain perivascular cells (pericytes are contractile and function normally to regulate vessel tone and morphology, have stem cell properties, are interconvertible with macrophages and are involved in new vessel formation during angiogenesis. Nevertheless, how pericytes contribute to brain tumor infiltration is not known. In this study we have investigated the underlying mechanism by which the most lethal brain cancer, Glioblastoma Multiforme (GBM interacts with pre-existing blood vessels (co-option to promote tumor initiation and progression. Here, using mouse xenografts and laminin-coated silicone substrates, we show that GBM malignancy proceeds via specific and previously unknown interactions of tumor cells with brain pericytes. Two-photon and confocal live imaging revealed that GBM cells employ novel, Cdc42-dependent and actin-based cytoplasmic extensions, that we call flectopodia, to modify the normal contractile activity of pericytes. This results in the co-option of modified pre-existing blood vessels that support the expansion of the tumor margin. Furthermore, our data provide evidence for GBM cell/pericyte fusion-hybrids, some of which are located on abnormally constricted vessels ahead of the tumor and linked to tumor-promoting hypoxia. Remarkably, inhibiting Cdc42 function impairs vessel co-option and converts pericytes to a phagocytic/macrophage-like phenotype, thus favoring an innate immune response against the tumor. Our work, therefore, identifies for the first time a key GBM contact-dependent interaction that switches pericyte function from tumor-suppressor to tumor-promoter, indicating that GBM may harbor the seeds of its own destruction. These data support the development of therapeutic strategies directed against co-option (preventing

  7. Are tumor-to-tumor differences in oxygenation responsible for the heterogeneity in the response of tumors to therapy

    International Nuclear Information System (INIS)

    Rockwell, S.; Moulder, J.E.; Martin, D.F.

    1984-01-01

    Individual tumors from the same transplanted tumor line often show very different responses to the same treatments, even when the tumors are implanted into similar sites in similar hosts and studied at the same time. The cause of this heterogeneity is unknown; either tumor or host factors could be responsible. Solid tumors contain large numbers of viable hypoxic cells, which are resistant to both radiotherapy and chemotherapy and limit the response of tumors to intensive treatments. To determine whether differences in the proportion of hypoxic cells in the tumors produce the observed variability in therapeutic sensitivity, the authors compared the radiation responses of normally-aerated tumors and tumors made artificially hypoxic. If large tumor-to-tumor differences in oxygenation exist, data from normally-aerated tumors should be more variable than data from hypoxic tumors (which should all be brought to uniform hypoxia and uniform radioresistance). Analysis of data from several tumor systems revealed the variability in the radiation responses of hypoxic tumors to be at least as great as that for aerobic tumors. Thus, factors other than differences in oxygenation must produce the heterogeneity in tumor radiation response

  8. Stanniocalcin-2 is a HIF-1 target gene that promotes cell proliferation in hypoxia

    Energy Technology Data Exchange (ETDEWEB)

    Law, Alice Y.S. [Department of Biology, Hong Kong Baptist University, Kowloon Tong (Hong Kong); Wong, Chris K.C., E-mail: ckcwong@hkbu.edu.hk [Department of Biology, Hong Kong Baptist University, Kowloon Tong (Hong Kong)

    2010-02-01

    Stanniocalcin-2 (STC2), the paralog of STC1, has been suggested as a novel target of oxidative stress response to protect cells from apoptosis. The expression of STC2 has been reported to be highly correlated with human cancer development. In this study, we reported that STC2 is a HIF-1 target gene and is involved in the regulation of cell proliferation. STC2 was shown to be up-regulated in different breast and ovarian cancer cells, following exposure to hypoxia. Using ovarian cancer cells (SKOV3), the underlying mechanism of HIF-1 mediated STC2 gene transactivation was characterized. Hypoxia-induced STC2 expression was found to be HIF-1{alpha} dependent and required the recruitment of p300 and HDAC7. Using STC2 promoter deletion constructs and site-directed mutagenesis, two authentic consensus HIF-1 binding sites were identified. Under hypoxic condition, the silencing of STC2 reduced while the overexpression of STC2 increased the levels of phosphorylated retinoblastoma and cyclin D in both SKOV3 and MCF7 cells. The change in cell cycle proteins correlated with the data of the serial cell counts. The results indicated that cell proliferation was reduced in STC2-silenced cells but was increased in STC2-overexpressing hypoxic cells. Solid tumor progression is usually associated with hypoxia. The identification and functional analysis of STC2 up-regulation by hypoxia, a feature of the tumor microenvironment, sheds light on a possible role for STC2 in tumors.

  9. Hypoxia-imaging with 18F-Misonidazole and PET: Changes of kinetics during radiotherapy of head-and-neck cancer

    International Nuclear Information System (INIS)

    Eschmann, Susanne Martina; Paulsen, Frank; Bedeshem, Claudia; Machulla, Hans-Juergen; Hehr, Thomas; Bamberg, Michael; Bares, Roland

    2007-01-01

    Background and purpose: PET with 18 F-Misonidazole (FMISO-PET) is a non-invasive method for measuring tumor hypoxia. We analysed changes of FMISO-uptake during radiotherapy and their impact on patient outcome. Materials and methods: Fourteen patients with HNC underwent repeated FMISO-PET prior to radiotherapy and after 30 Gy. Dynamic and static PET-scans (2 + 4 h p.i.) were acquired. FMISO-uptake was quantified by calculating standard uptake values (SUV) and tumor-muscle-ratios (TMR). Kinetic curve types representing tissue hypoxia were defined. Change of curve type was correlated with patient outcome. Results: The mean SUV 4 h p.i. and the TMR decreased significantly during radiotherapy. SUV decreased clearly in 12/14 patients, and increased in 2 patients. TMR decreased in 11 patients, and increased in 3 patients. Prior to radiotherapy, three different shapes of kinetic curve types indicative for the degree of hypoxia could be defined in 12/14 patients: (1) accumulation type (severe hypoxia (n = 8)) (2) intermediate type (intermediate degree of hypoxia (n = 3)), and (3) wash-out type (low degree of hypoxia (n = 1)). Curve type changed towards a lower degree of hypoxia at 30 Gy in all but 3 patients. In three patients curve type remained unchanged. Conclusions: The changes in tumor FMISO-uptake during radiotherapy indicate radio-induced reoxygenation

  10. Plasma volume in acute hypoxia

    DEFF Research Database (Denmark)

    Poulsen, T D; Klausen, T; Richalet, J P

    1998-01-01

    Exposure to acute hypoxia is associated with changes in body fluid homeostasis and plasma volume (PV). This study compared a dye dilution technique using Evans' blue (PV[Evans']) with a carbon monoxide (CO) rebreathing method (PV[CO]) for measurements of PV in ten normal subjects at sea level...... and again 24 h after rapid passive ascent to high altitude (4,350 m). Hypobaric hypoxia decreased arterial oxygen saturation to 79 (74-83)% (mean with 95% confidence intervals). The PV(Evans') remained unchanged from 3.49 (3.30-3.68) l at sea level to 3.46 (3.24-3.68) l at high altitude. In contrast PV......(Evans') and PV(CO) increased from 1.04 (0.99-1.09) at sea level to 1.15 (1.06-1.24) at high altitude (P hypoxia-induced changes in PV. The mechanism responsible for the bias remains unknown, but it is suggested that the results may...

  11. Differentiation-associated staining with anti-pimonidazole antibodies in head and neck tumors.

    NARCIS (Netherlands)

    Janssen, H.L.K.; Hoebers, F.J.; Sprong, D.; Goethals, L.; Williams, K.J.; Stratford, I.J.; Haustermans, K.; Balm, A.J.M.; Begg, A.C.

    2004-01-01

    BACKGROUND AND PURPOSE: Hypoxia is a strong negative prognostic factor for all three major treatment modalities for cancer. The bioreductive drug pimonidazole is currently under clinical investigation as a hypoxia marker. In human head and neck tumors, in addition to staining patterns typical of

  12. Differentiation-associated staining with anti-pimonidazole antibodies in head and neck tumors

    NARCIS (Netherlands)

    Janssen, Hilde L. K.; Hoebers, Frank J.; Sprong, Debbie; Goethals, Laurence; Williams, Kaye J.; Stratford, Ian J.; Haustermans, Karin M.; Balm, Alfons J.; Begg, Adrian C.

    2004-01-01

    BACKGROUND AND PURPOSE: Hypoxia is a strong negative prognostic factor for all three major treatment modalities for cancer. The bioreductive drug pimonidazole is currently under clinical investigation as a hypoxia marker. In human head and neck tumors, in addition to staining patterns typical of

  13. Cognition Effects of Low-Grade Hypoxia

    Science.gov (United States)

    2016-07-01

    Denison found a significant effect on rate of learning, suggesting that hypoxia affected learning and memory at lower altitudes such as 2438 m (8000 ft...studies, reported memory and learning were not affected by hypoxia at any altitude below 3658 m (12,000 ft).2,3,10,11 Fowler et al. also came to the...significant result, it seems likely that hypoxia affects working memory capacity by decreasing an individual’s ability to quickly encode and recall

  14. The regulation of transcriptional repression in hypoxia

    OpenAIRE

    Cavadas, Miguel A.S.; Cheong, Alex; Taylor, Cormac T.

    2017-01-01

    A sufficient supply molecular oxygen is essential for the maintenance of physiologic metabolism and bioenergetic homeostasis for most metazoans. For this reason, mechanisms have evolved for eukaryotic cells to adapt to conditions where oxygen demand exceeds supply (hypoxia). These mechanisms rely on the modification of pre-existing proteins, translational arrest and transcriptional changes. The hypoxia inducible factor (HIF; a master regulator of gene induction in response to hypoxia) is resp...

  15. Bone tumor

    Science.gov (United States)

    Tumor - bone; Bone cancer; Primary bone tumor; Secondary bone tumor; Bone tumor - benign ... The cause of bone tumors is unknown. They often occur in areas of the bone that grow rapidly. Possible causes include: Genetic defects ...

  16. The role of hypoxia inducible factor 1 (HIF-1) in hypoxia induced apoptosis

    NARCIS (Netherlands)

    Greijer, A.E.; Wall, E. van der

    2004-01-01

    Apoptosis can be induced in response to hypoxia. The severity of hypoxia determines whether cells become apoptotic or adapt to hypoxia and survive. A hypoxic environment devoid of nutrients prevents the cell undergoing energy dependent apoptosis and cells become necrotic. Apoptosis regulatory

  17. Whole brain radiation-induced impairments in learning and memory are time-sensitive and reversible by systemic hypoxia.

    Science.gov (United States)

    Warrington, Junie P; Csiszar, Anna; Mitschelen, Matthew; Lee, Yong Woo; Sonntag, William E

    2012-01-01

    Whole brain radiation therapy (WBRT) is commonly used for treatment of primary and metastatic brain tumors; however, cognitive impairment occurs in 40-50% of brain tumor survivors. The etiology of the cognitive impairment following WBRT remains elusive. We recently reported that radiation-induced cerebrovascular rarefaction within hippocampal subregions could be completely reversed by systemic hypoxia. However, the effects of this intervention on learning and memory have not been reported. In this study, we assessed the time-course for WBRT-induced impairments in contextual and spatial learning and the capacity of systemic hypoxia to reverse WBRT-induced deficits in spatial memory. A clinical fractionated series of 4.5Gy WBRT was administered to mice twice weekly for 4 weeks, and after various periods of recovery, behavioral analyses were performed. To study the effects of systemic hypoxia, mice were subjected to 11% (hypoxia) or 21% oxygen (normoxia) for 28 days, initiated 1 month after the completion of WBRT. Our results indicate that WBRT induces a transient deficit in contextual learning, disruption of working memory, and progressive impairment of spatial learning. Additionally, systemic hypoxia completely reversed WBRT-induced impairments in learning and these behavioral effects as well as increased vessel density persisted for at least 2 months following hypoxia treatment. Our results provide critical support for the hypothesis that cerebrovascular rarefaction is a key component of cognitive impairment post-WBRT and indicate that processes of learning and memory, once thought to be permanently impaired after WBRT, can be restored.

  18. {sup 1}H NMR metabolomics identification of markers of hypoxia-induced metabolic shifts in a breast cancer model system

    Energy Technology Data Exchange (ETDEWEB)

    Weljie, Aalim M., E-mail: aweljie@ucalgary.ca [University of Calgary, Department of Biological Sciences (Canada); Bondareva, Alla [Department of Comparative Biology and Experimental Medicine (Canada); Zang, Ping [University of Calgary, Department of Chemistry (Canada); Jirik, Frank R. [McCaig Institute for Bone and Joint Health, Department of Biochemistry and Molecular Biology (Canada)

    2011-04-15

    Hypoxia can promote invasive behavior in cancer cells and alters the response to therapeutic intervention as a result of changes in the expression many genes, including genes involved in intermediary metabolism. Although metabolomics technologies are capable of simultaneously measuring a wide range of metabolites in an untargeted manner, these methods have been relatively under utilized in the study of cancer cell responses to hypoxia. Thus, {sup 1}H NMR metabolomics was used to examine the effects of hypoxia in the MDA-MB-231 human breast cancer cell line, both in vitro and in vivo. Cell cultures were compared with respect to their metabolic responses during growth under either hypoxic (1% O{sub 2}) or normoxic conditions. Orthogonal partial least squares discriminant analysis (OPLS-DA) was used to identify a set of metabolites that were responsive to hypoxia. Via intracardiac administration, MDA-MB-231 cells were also used to generate widespread metastatic disease in immuno-compromised mice. Serum metabolite analysis was conducted to compare animals with and without a large tumor burden. Intriguingly, using a cross-plot of the OPLS loadings, both the in vitro and in vivo samples yielded a subset of metabolites that were significantly altered by hypoxia. These included primarily energy metabolites and amino acids, indicative of known alterations in energy metabolism, and possibly protein synthesis or catabolism. The results suggest that the metabolite pattern identified might prove useful as a marker for intra-tumoral hypoxia.

  19. Notch1 is required for hypoxia-induced proliferation, invasion and chemoresistance of T-cell acute lymphoblastic leukemia cells

    Directory of Open Access Journals (Sweden)

    Zou Jie

    2013-01-01

    Full Text Available Abstract Background Notch1 is a potent regulator known to play an oncogenic role in many malignancies including T-cell acute lymphoblastic leukemia (T-ALL. Tumor hypoxia and increased hypoxia-inducible factor-1α (HIF-1α activity can act as major stimuli for tumor aggressiveness and progression. Although hypoxia-mediated activation of the Notch1 pathway plays an important role in tumor cell survival and invasiveness, the interaction between HIF-1α and Notch1 has not yet been identified in T-ALL. This study was designed to investigate whether hypoxia activates Notch1 signalling through HIF-1α stabilization and to determine the contribution of hypoxia and HIF-1α to proliferation, invasion and chemoresistance in T-ALL. Methods T-ALL cell lines (Jurkat, Sup-T1 transfected with HIF-1α or Notch1 small interference RNA (siRNA were incubated in normoxic or hypoxic conditions. Their potential for proliferation and invasion was measured by WST-8 and transwell assays. Flow cytometry was used to detect apoptosis and assess cell cycle regulation. Expression and regulation of components of the HIF-1α and Notch1 pathways and of genes related to proliferation, invasion and apoptosis were assessed by quantitative real-time PCR or Western blot. Results Hypoxia potentiated Notch1 signalling via stabilization and activation of the transcription factor HIF-1α. Hypoxia/HIF-1α-activated Notch1 signalling altered expression of cell cycle regulatory proteins and accelerated cell proliferation. Hypoxia-induced Notch1 activation increased the expression of matrix metalloproteinase-2 (MMP2 and MMP9, which increased invasiveness. Of greater clinical significance, knockdown of Notch1 prevented the protective effect of hypoxia/HIF-1α against dexamethasone-induced apoptosis. This sensitization correlated with losing the effect of hypoxia/HIF-1α on Bcl-2 and Bcl-xL expression. Conclusions Notch1 signalling is required for hypoxia/HIF-1α-induced proliferation

  20. Hypoxia-Related MicroRNA-210 Is a Diagnostic Marker for Discriminating Osteoblastoma and Osteosarcoma

    Science.gov (United States)

    Riester, Scott M.; Torres-Mora, Jorge; Dudakovic, Amel; Camilleri, Emily T.; Wang, Wei; Xu, Fuhua; Thaler, Roman R.; Evans, Jared M.; Zwartbol, René; Briaire-de Bruijn, Inge H.; Maran, Avudaiappan; Folpe, Andrew L.; Inwards, Carrie Y.; Rose, Peter S.; Shives, Thomas C.; Yaszemski, Michael J.; Sim, Franklin H.; Deyle, David R.; Larson, Annalise N.; Galindo, Mario A.; Cleven, Arjen G. H.; Oliveira, Andre M.; Cleton-Jansen, Anne-Marie; Bovée, Judith V. M. G.; van Wijnen, Andre J.

    2017-01-01

    Osteoblastoma is a benign bone tumor that can often be difficult to distinguish from malignant osteosarcoma. Because misdiagnosis can result in unfavorable clinical outcomes, we have investigated microRNAs as potential diagnostic biomarkers for distinguishing between these two tumor types. Next generation RNA sequencing was used as an expression screen to evaluate >2,000 microRNAs present in tissue derived from rare formalin fixed paraffin embedded (FFPE) archival tumor specimens. MicroRNAs displaying the greatest ability to discriminate between these two tumors were validated on an independent tumor set, using qPCR assays. Initial screening by RNA-seq identified four microRNA biomarker candidates. Expression of three miRNAs (miR-451a, miR-144-3p, miR-486-5p) was higher in osteoblastoma, while the miR-210 was elevated in osteosarcoma. Validation of these microRNAs on an independent data set of 22 tumor specimens by qPCR revealed that miR-210 is the most discriminating marker. This microRNA displays low levels of expression across all of the osteoblastoma specimens and robust expression in the majority of the osteosarcoma specimens. Application of these biomarkers to a clinical test case showed that these microRNA biomarkers permit re-classification of a misdiagnosed FFPE tumor sample from osteoblastoma to osteosarcoma. Our findings establish that the hypoxia-related miR-210 is a discriminatory marker that distinguishes between osteoblastoma and osteosarcoma. This discovery provides a complementary molecular approach to support pathological classification of two diagnostically challenging musculoskeletal tumors. Because miR-210 is linked to the cellular hypoxia response, its detection may be linked to well-established pro-angiogenic and metastatic roles of hypoxia in osteosarcomas and other tumor cell types. PMID:27324965

  1. New tracers developed in positron emission tomography: a possible second breath in targeting tumour hypoxia?

    International Nuclear Information System (INIS)

    Baillet, G.; Groheux, D.; Barre, E.; Toubert, M.E.; Dechaud, C.; Teyton, P.; Moretti, J.L.; Le Beau de Hemricourt, E.

    2007-01-01

    There is an increasing interest for targeting of tumor hypoxia and our paper aimed to emphasize the main points of this topic. We review new insights at cellular level and focus on the leading part of hypoxia inducible factor one alpha and its connections with angio genesis. We shortly describe different methods to assess tissue hypoxia then zoom on to positron emission tomography and its acknowledged tracers 18 F-fluoro misonidazole and 18 F-fluoro-erythro-nitroimidazole. Recent studies concerning two new promising tracers Cu(II)-di-acetyl-bis(N(4)-methyl-thio-semicarbazone) and FAZA are reviewed, and the respective value of the tracers is discussed. (N.C.)

  2. Isoflurane preserves spatial working memory in adult mice after moderate hypoxia.

    Science.gov (United States)

    Bekker, Alex; Shah, Romin; Quartermain, David; Li, Yong-Sheng; Blanck, Thomas

    2006-04-01

    Perioperative hypoxia may contribute to postoperative cognitive impairment. It is unknown, however, whether anesthetics exacerbate or protect against hypoxia-related central nervous system impairment. We sought to determine whether hypoxia alone or in combination with isoflurane disrupts working memory in mice. To this extent, we assigned adult mice to one of four treatments for 1 h: oxygen 21%, oxygen 21% + isoflurane 1.2%, oxygen 8%, or oxygen 8% + isoflurane 1.2%. Mice breathed spontaneously throughout the experiment. Body temperature was maintained at 37 degrees C + 0.5 degrees C. Mice were allowed to recover for 24 h to avoid the confounding influence of residual anesthetics on neurobehavioral performance. Working memory was assessed by use of a Y maze modified for mice. For the training trial, entry to one arm was blocked and mice were permitted to run between the two open arms for 15 min and inspect the objects outside. For the test trial, carried out 1 h later, all arms were open. Time spent in each arm was automatically recorded by a camera and associated software. Mice were tested 1, 4, and 7 days after anesthesia. A different arm was used as the novel arm for each test. Performance was analyzed with repeated-measurements analysis of variance, followed by analysis of simple main effects and by post hoc comparison using Newman-Keuls test when appropriate. P values hypoxia (8% oxygen for 1 h) spent significantly less time in the novel arm 1 day after the insult. The impairment, however, was transient. Hypoxic mice performance improved to the level of the control animals on the fourth post-treatment day. Mice subjected to hypoxia plus isoflurane exhibited no impairment and were comparable to the control group at all time points. Hypoxia transiently impairs performance in a spatial memory task. It appears that isoflurane protects against this deleterious effect of hypoxia.

  3. Zinc promotes the death of hypoxic astrocytes by upregulating hypoxia-induced hypoxia-inducible factor-1alpha expression via poly(ADP-ribose) polymerase-1.

    Science.gov (United States)

    Pan, Rong; Chen, Chen; Liu, Wen-Lan; Liu, Ke-Jian

    2013-07-01

    Pathological release of excess zinc ions has been implicated in ischemic brain cell death. However, the underlying mechanisms remain to be elucidated. In stroke, ischemia-induced zinc release and hypoxia-inducible factor-1 (HIF-1) accumulation concurrently occur in the ischemic tissue. The present study tests the hypothesis that the presence of high intracellular zinc concentration is a major cause of modifications to PARP-1 and HIF-1α during hypoxia, which significantly contributes to cell death during ischemia. Primary cortical astrocytes and C8-D1A cells were exposed to different concentrations of zinc chloride. Cell death rate and protein expression of HIF-1 and Poly(ADP-ribose) polymerase (PARP)-1 were examined after 3-h hypoxic treatment. Although 3-h hypoxia or 100 μM of zinc alone did not induce noticeable cytotoxicity, their combination led to a dramatic increase in astrocytic cell death in a zinc-concentration-dependent manner. Exposure of astrocytes to hypoxia for 3 h remarkably increased the levels of intracellular zinc and HIF-1α protein, which was further augmented by added exogenous zinc. Notably, HIF-1α knockdown blocked zinc-induced astrocyte death. Moreover, knockdown of PARP-1, another important protein in the response of hypoxia, attenuated the overexpression of HIF-1α and reduced the cell death rate. Our studies show that zinc promotes hypoxic cell death through overexpression of the hypoxia response factor HIF-1α via the cell fate determine factor PARP-1 modification, which provides a novel mechanism for zinc-mediated ischemic brain injury. © 2013 John Wiley & Sons Ltd.

  4. The role of the pontine respiratory complex in the response to intermittent hypoxia.

    Science.gov (United States)

    Boon, Joyce A; Milsom, William K

    2010-04-30

    These experiments were designed to determine the effects of EEG state on the response of rats to intermittent hypoxia and to test the hypotheses that short-term potentiation (STP) and ventilatory long term facilitation (vLTF) are state dependent; and that neurons with NMDA receptors in the dorso-ventral pontine respiratory group (dvPRG) modulate the development of STP and vLTF in rats. Low-doses of urethane anaesthesia (hypoxia result in cycling between EEG states that superficially resemble wake and slow wave sleep in rats and are accompanied by changes in breathing pattern that closely resemble those seen when unanaesthetized rats cycle between wake and SWS. When changes between these states were accounted for, intermittent, poikilocapnic hypoxia did not produce a significant vLTF. However, there was a persistent STP of tidal volume and vLTF did develop after blockade of NMDAr in the region of the PBrKF complex by microinjection of MK-801. Blockade of NMDA-type glutamate receptor-mediated processes in the dorsal pons also caused animals to cycle into State III, but did not alter the response to either continuous or intermittent hypoxia indicating that the response to hypoxia was not state dependent. This shows that neurons in the region of the PRG inhibit STP and vLTF, but no longer do so if PRG NMDA receptor activation is blocked. (c) 2010 Elsevier B.V. All rights reserved.

  5. [Impact of chronic intermittent hypoxia upon rat liver lipid metabolism and interventional effect of Tempol].

    Science.gov (United States)

    Zhao, Hai-yan; Chen, Bao-yuan; Guo, Run; Kong, Cheng-ying; Wan, Nan-sheng; Zhang, Jing

    2013-02-05

    To explore the impact of chronic intermittent hypoxia (CIH) upon rat liver lipid metabolism and effect of anti-oxidant Tempol. Male Wistar rats (n = 80) were randomly divided into intermittent hypoxia group (10, 20, 30, 40 times/h), intermittent hypoxia Tempol treatment group, intermittent hypoxia normal saline treatment group, intermittent air mimic group (IA) and blank control group (CG). Sections of liver were stained with hematoxylin and eosin. Serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured. Levels of liver homogenate triglyceride (TG), total cholesterol (TC), free fatty acids (FFA) and serum TG, TC, adiponectin (ADP) were measured. Liver histology: IH group exhibited hepatocellular swelling, hyperchromatosis, disrupted hepatocellular membrane. With the increase of frequency, there were local necrosis and infiltration of inflammatory cells. But no steatosis was seen. Tempol early treatment and IA groups exhibited no hepatocellular swelling or inflammatory cell infiltration. The activities of ALT and AST increased along with the increased frequency in IH group (all P Tempol treatment group, and more obviously when early intervention was applied (all P 0.05), and no difference in different frequencies in IH group (all P > 0.05). The levels of serum TG, TC in IH groups were higher than those in IA and CG groups while ADP was lower (all P Tempol treatment group, serum TG, TC decreased while ADP increased and changed more obviously when early intervention was applied (all P Tempol can block intermittent hypoxia associated with liver injury.

  6. Hypoxia Decreases Invasin-Mediated Yersinia enterocolitica Internalization into Caco-2 Cells.

    Science.gov (United States)

    Zeitouni, Nathalie E; Dersch, Petra; Naim, Hassan Y; von Köckritz-Blickwede, Maren

    2016-01-01

    Yersinia enterocolitica is a major cause of human yersiniosis, with enterocolitis being a typical manifestation. These bacteria can cross the intestinal mucosa, and invade eukaryotic cells by binding to host β1 integrins, a process mediated by the bacterial effector protein invasin. This study examines the role of hypoxia on the internalization of Y. enterocolitica into intestinal epithelial cells, since the gastrointestinal tract has been shown to be physiologically deficient in oxygen levels (hypoxic), especially in cases of infection and inflammation. We show that hypoxic pre-incubation of Caco-2 cells resulted in significantly decreased bacterial internalization compared to cells grown under normoxia. This phenotype was absent after functionally blocking host β1 integrins as well as upon infection with an invasin-deficient Y. enterocolitica strain. Furthermore, downstream phosphorylation of the focal adhesion kinase was also reduced under hypoxia after infection. In good correlation to these data, cells grown under hypoxia showed decreased protein levels of β1 integrins at the apical cell surface whereas the total protein level of the hypoxia inducible factor (HIF-1) alpha was elevated. Furthermore, treatment of cells with the HIF-1 α stabilizer dimethyloxalylglycine (DMOG) also reduced invasion and decreased β1 integrin protein levels compared to control cells, indicating a potential role for HIF-1α in this process. These results suggest that hypoxia decreases invasin-integrin-mediated internalization of Y. enterocolitica into intestinal epithelial cells by reducing cell surface localization of host β1 integrins.

  7. Metabolomic Dynamic Analysis of Hypoxia in MDA-MB-231 and the Comparison with Inferred Metabolites from Transcriptomics Data

    International Nuclear Information System (INIS)

    Tsai, I-Lin; Kuo, Tien-Chueh; Ho, Tsung-Jung; Harn, Yeu-Chern; Wang, San-Yuan; Fu, Wen-Mei; Kuo, Ching-Hua; Tseng, Yufeng Jane

    2013-01-01

    Hypoxia affects the tumor microenvironment and is considered important to metastasis progression and therapy resistance. Thus far, the majority of global analyses of tumor hypoxia responses have been limited to just a single omics level. Combining multiple omics data can broaden our understanding of tumor hypoxia. Here, we investigate the temporal change of the metabolite composition with gene expression data from literature to provide a more comprehensive insight into the system level in response to hypoxia. Nuclear magnetic resonance spectroscopy was used to perform metabolomic profiling on the MDA-MB-231 breast cancer cell line under hypoxic conditions. Multivariate statistical analysis revealed that the metabolic difference between hypoxia and normoxia was similar over 24 h, but became distinct over 48 h. Time dependent microarray data from the same cell line in the literature displayed different gene expressions under hypoxic and normoxic conditions mostly at 12 h or earlier. The direct metabolomic profiles show a large overlap with theoretical metabolic profiles deduced from previous transcriptomic studies. Consistent pathways are glycolysis/gluconeogenesis, pyruvate, purine and arginine and proline metabolism. Ten metabolic pathways revealed by metabolomics were not covered by the downstream of the known transcriptomic profiles, suggesting new metabolic phenotypes. These results confirm previous transcriptomics understanding and expand the knowledge from existing models on correlation and co-regulation between transcriptomic and metabolomics profiles, which demonstrates the power of integrated omics analysis

  8. Scriptaid overcomes hypoxia-induced cisplatin resistance in both wild-type and mutant p53 lung cancer cells.

    Science.gov (United States)

    Pradhan, Shrikant; Mahajan, Divyank; Kaur, Prabhjot; Pandey, Namita; Sharma, Chandresh; Srivastava, Tapasya

    2016-11-01

    Non-small cell lung cancer (NSCLC), comprising 85% of lung cancer cases, has been associated with resistance to chemo/radiotherapy. The hypoxic tumor micro-environment, where insufficient vasculature results in poor drug penetrance and sub-optimal chemotherapy in the tumor interiors contributes heavily to this resistance. Additionally, epigenetic changes in tumorigenic cells also change their response to different forms of therapy. In our study, we have investigated the effectiveness of a combination of cisplatin with scriptaid [a pan-Histone Deacetylase inhibitor (HDACi)] in a model that mimics the tumor microenvironment of hypoxia and sub-lethal chemotherapy. Scriptaid synergistically increases the efficacy of cisplatin in normoxia as well as hypoxia, accompanied with reduced metastasis and enhanced DNA damage. Addition of scriptaid also overcomes the cisplatin resistance exhibited in lung cancer cells with stabilized hypoxia inducible factor 1 (HIF1)-α (mutant) and mutant p53. Molecular studies showed that the combination treatment increased apoptotic cell death in both normoxia and hypoxia with a dual role of p38MAPK. Together, our results suggest that the combination of low dose cisplatin and scriptaid is cytotoxic to NSCLC lines, can overcome hypoxia induced resistance and mutant p53- induced instability often associated with this cancer, and has the potential to be an effective therapeutic modality.

  9. Metabolomic Dynamic Analysis of Hypoxia in MDA-MB-231 and the Comparison with Inferred Metabolites from Transcriptomics Data

    Directory of Open Access Journals (Sweden)

    Yufeng Jane Tseng

    2013-05-01

    Full Text Available Hypoxia affects the tumor microenvironment and is considered important to metastasis progression and therapy resistance. Thus far, the majority of global analyses of tumor hypoxia responses have been limited to just a single omics level. Combining multiple omics data can broaden our understanding of tumor hypoxia. Here, we investigate the temporal change of the metabolite composition with gene expression data from literature to provide a more comprehensive insight into the system level in response to hypoxia. Nuclear magnetic resonance spectroscopy was used to perform metabolomic profiling on the MDA-MB-231 breast cancer cell line under hypoxic conditions. Multivariate statistical analysis revealed that the metabolic difference between hypoxia and normoxia was similar over 24 h, but became distinct over 48 h. Time dependent microarray data from the same cell line in the literature displayed different gene expressions under hypoxic and normoxic conditions mostly at 12 h or earlier. The direct metabolomic profiles show a large overlap with theoretical metabolic profiles deduced from previous transcriptomic studies. Consistent pathways are glycolysis/gluconeogenesis, pyruvate, purine and arginine and proline metabolism. Ten metabolic pathways revealed by metabolomics were not covered by the downstream of the known transcriptomic profiles, suggesting new metabolic phenotypes. These results confirm previous transcriptomics understanding and expand the knowledge from existing models on correlation and co-regulation between transcriptomic and metabolomics profiles, which demonstrates the power of integrated omics analysis.

  10. Metabolomic Dynamic Analysis of Hypoxia in MDA-MB-231 and the Comparison with Inferred Metabolites from Transcriptomics Data

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, I-Lin [Department of Pharmacy, National Taiwan University, No. 1, Jen-Ai Road, Section 1 Taipei 10051, Taiwan (China); The Metabolomics Group, National Taiwan University, Taipei 106, Taiwan (China); Center for Genomic Medicine, National Taiwan University, Taipei 10051, Taiwan (China); Kuo, Tien-Chueh [The Metabolomics Group, National Taiwan University, Taipei 106, Taiwan (China); Graduate Institute of Biomedical Electronic and Bioinformatics, National Taiwan University, Room 410 BL Building, No. 1, Roosevelt Road, Sec. 4, Taipei 106, Taiwan (China); Ho, Tsung-Jung [The Metabolomics Group, National Taiwan University, Taipei 106, Taiwan (China); Department of Computer Science and Information Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan (China); Harn, Yeu-Chern [The Metabolomics Group, National Taiwan University, Taipei 106, Taiwan (China); Graduate Institute of Networking and Multimedia, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan (China); Wang, San-Yuan [The Metabolomics Group, National Taiwan University, Taipei 106, Taiwan (China); Department of Computer Science and Information Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan (China); Fu, Wen-Mei [Department of Pharmacology, National Taiwan University, 11 F No. 1 Sec. 1, Ren-ai Rd., Taipei 10051, Taiwan (China); Kuo, Ching-Hua, E-mail: kuoch@ntu.edu.tw [Department of Pharmacy, National Taiwan University, No. 1, Jen-Ai Road, Section 1 Taipei 10051, Taiwan (China); The Metabolomics Group, National Taiwan University, Taipei 106, Taiwan (China); Center for Genomic Medicine, National Taiwan University, Taipei 10051, Taiwan (China); Tseng, Yufeng Jane, E-mail: kuoch@ntu.edu.tw [Department of Pharmacy, National Taiwan University, No. 1, Jen-Ai Road, Section 1 Taipei 10051, Taiwan (China); The Metabolomics Group, National Taiwan University, Taipei 106, Taiwan (China); Center for Genomic Medicine, National Taiwan University, Taipei 10051, Taiwan (China); Graduate Institute of Biomedical Electronic and Bioinformatics, National Taiwan University, Room 410 BL Building, No. 1, Roosevelt Road, Sec. 4, Taipei 106, Taiwan (China); Department of Computer Science and Information Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan (China)

    2013-05-03

    Hypoxia affects the tumor microenvironment and is considered important to metastasis progression and therapy resistance. Thus far, the majority of global analyses of tumor hypoxia responses have been limited to just a single omics level. Combining multiple omics data can broaden our understanding of tumor hypoxia. Here, we investigate the temporal change of the metabolite composition with gene expression data from literature to provide a more comprehensive insight into the system level in response to hypoxia. Nuclear magnetic resonance spectroscopy was used to perform metabolomic profiling on the MDA-MB-231 breast cancer cell line under hypoxic conditions. Multivariate statistical analysis revealed that the metabolic difference between hypoxia and normoxia was similar over 24 h, but became distinct over 48 h. Time dependent microarray data from the same cell line in the literature displayed different gene expressions under hypoxic and normoxic conditions mostly at 12 h or earlier. The direct metabolomic profiles show a large overlap with theoretical metabolic profiles deduced from previous transcriptomic studies. Consistent pathways are glycolysis/gluconeogenesis, pyruvate, purine and arginine and proline metabolism. Ten metabolic pathways revealed by metabolomics were not covered by the downstream of the known transcriptomic profiles, suggesting new metabolic phenotypes. These results confirm previous transcriptomics understanding and expand the knowledge from existing models on correlation and co-regulation between transcriptomic and metabolomics profiles, which demonstrates the power of integrated omics analysis.

  11. Direct effect of chronic hypoxia in suppressing large conductance Ca(2+)-activated K(+) channel activity in ovine uterine arteries via increasing oxidative stress.

    Science.gov (United States)

    Hu, Xiang-Qun; Huang, Xiaohui; Xiao, Daliao; Zhang, Lubo

    2016-01-15

    Chronic hypoxia has a direct effect in down-regulating the BKCa channel β1 subunit and inhibiting the BKCa channel activity in uterine arteries of pregnant sheep. Oxidative stress plays a causal role in hypoxia-mediated suppression of BKCa channel function. The steroid hormone-induced effect on BKCa channels is a target of hypoxia-mediated oxidative stress. Inhibition of oxidative stress ameliorates the adverse effect of hypoxia both ex vivo and in vivo in pregnant sheep exposed to long-term high-altitude hypoxia. Our findings provide novel evidence of a causative role of oxidative stress in hypoxia-mediated inhibition of the BKCa channel activity in uterine arteries and new insights in understanding and alleviating pregnancy complications associated with gestational hypoxia such as pre-eclampsia and fetal growth restriction. Uterine arteries of pregnant sheep acclimatized to long-term high-altitude hypoxia were associated with a decrease in large-conductance Ca(2+)-activated K(+) (BKCa) channel activity. The present study tested the hypothesis that prolonged hypoxia has a direct effect in suppressing BKCa channel activity by increasing oxidative stress. Uterine arteries were isolated from non-pregnant and near-term (∼142 days) pregnant sheep, and were treated ex vivo with 21.0 or 10.5% O2 for 48 h. The hypoxia treatment significantly increased the production of reactive oxygen species in uterine arteries, which was blocked by N-acetylcysteine. In uterine arteries of pregnant sheep, hypoxia significantly inhibited BKCa channel current density, decreased NS1619-induced relaxations and increased pressure-dependent tone, which were annulled by N-acetylcysteine. In accordance, hypoxia resulted in down-regulation of BKCa channel β1 subunit, which was restored in the presence of N-acetylcysteine. In addition, the N-acetylcysteine treatment significantly increased BKCa channel β1 subunit abundance and BKCa channel current density in uterine arteries from pregnant

  12. Hypoxia imaging with [F-18] FMISO-PET in head and neck cancer: Potential for guiding intensity modulated radiation therapy in overcoming hypoxia-induced treatment resistance

    International Nuclear Information System (INIS)

    Hendrickson, Kristi; Phillips, Mark; Smith, Wade; Peterson, Lanell; Krohn, Kenneth; Rajendran, Joseph

    2011-01-01

    Background and purpose: Positron emission tomography (PET) imaging with [F-18] fluoromisonidazole (FMISO) has been validated as a hypoxic tracer . Head and neck cancer exhibits hypoxia, inducing aggressive biologic traits that impart resistance to treatment. Delivery of modestly higher radiation doses to tumors with stable areas of chronic hypoxia can improve tumor control . Advanced radiation treatment planning (RTP) and delivery techniques such as intensity modulated radiation therapy (IMRT) can deliver higher doses to a small volume without increasing morbidity. We investigated the utility of co-registered FMISO-PET and CT images to develop clinically feasible RTPs with higher tumor control probabilities (TCP). Materials and methods: FMISO-PET images were used to determine hypoxic sub-volumes for boost planning. Example plans were generated for 10 of the patients in the study who exhibited significant hypoxia. We created an IMRT plan for each patient with a simultaneous integrated boost (SIB) to the hypoxic sub-volumes. We also varied the boost for two patients. Result: A significant (mean 17%, median 15%) improvement in TCP is predicted when the modest additional boost dose to the hypoxic sub-volume is included. Conclusion: Combined FMISO-PET imaging and IMRT planning permit delivery of higher doses to hypoxic regions, increasing the predicted TCP (mean 17%) without increasing expected complications.

  13. Effects of hypoxia on expression of a panel of stem cell and chemosensitivity markers in glioblastoma cell line-derived spheroids

    DEFF Research Database (Denmark)

    Kolenda, Jesper; Jensen, Stine Skov; Aaberg-Jessen, Charlotte

    Glioblastomas are the most frequent and malignant primary brain tumor. Tumor stem cells in these tumors have recently been suggested to possess innate resistance mechanisms against radiation and chemotherapy possibly explaining their high level of therapeutic resistance. Moreover tumor hypoxia...... of a panel of stem cell and chemosensitivity markers was therefore investigated using glioma spheroids derived from the conventional glioblastoma cell line U87. The glioma spheroids were derived at normoxic (21% O2) and hypoxic (1% O2) culturing conditions in serum-free medium with EGF and bFGF. The entire...... immunohistochemical panel included hypoxia (HIF-1α, HIF-2α), proliferation (Ki-67) and stem cell (CD133, nestin, podoplanin, Bmi-1, Sox-2) markers as well as markers related to chemosensitivity (MGMT, MDR-1, TIMP-1, Lamp-1). Since spheroids derived in hypoxia were smaller than in normoxia, a set of experiments...

  14. Phosphorylation of eIF2α is required for mRNA translation inhibition and survival during moderate hypoxia

    International Nuclear Information System (INIS)

    Koritzinsky, Marianne; Rouschop, Kasper M.A.; Beucken, Twan van den; Magagnin, Michael G.; Savelkouls, Kim; Lambin, Philippe; Wouters, Bradly G.

    2007-01-01

    Abstracts: Background and purpose: Human tumors are characterized by temporal fluctuations in oxygen tension. The biological pathways that respond to the dynamic tumor microenvironment represent potential molecular targets for cancer therapy. Anoxic conditions result in eIF2α dependent inhibition of overall mRNA translation, differential gene expression, hypoxia tolerance and tumor growth. The signaling pathway which governs eIF2α phosphorylation has therefore emerged as a potential molecular target. In this study, we investigated the role of eIF2α in regulating mRNA translation and hypoxia tolerance during moderate hypoxia. Since other molecular pathways that regulate protein synthesis are frequently mutated in cancer, we also assessed mRNA translation in a panel of cell lines from different origins. Materials and methods: Immortalized human fibroblast, transformed mouse embryo fibroblasts (MEFs) and cells from six cancer cell lines were exposed to 0.2% or 0.0% oxygen. We assayed global mRNA translation efficiency by polysome analysis, as well as proliferation and clonogenic survival. The role of eIF2α was assessed in MEFs harboring a homozygous inactivating mutation (S51A) as well as in U373-MG cells overexpressing GADD34 (C-term) under a tetracycline-dependent promoter. The involvement of eIF4E regulation was investigated in HeLa cells stably expressing a short hairpin RNA (shRNA) targeting 4E-BP1. Results: All cells investigated inhibited mRNA translation severely in response to anoxia and modestly in response to hypoxia. Two independent genetic cell models demonstrated that inhibition of mRNA translation in response to moderate hypoxia was dependent on eIF2α phosphorylation. Disruption of eIF2α phosphorylation caused sensitivity to hypoxia and anoxia. Conclusions: Disruption of eIF2α phosphorylation is a potential target for hypoxia-directed molecular cancer therapy

  15. Hypoxia disrupts the Fanconi anemia pathway and sensitizes cells to chemotherapy through regulation of UBE2T

    International Nuclear Information System (INIS)

    Ramaekers, Chantal H.M.A.; Beucken, Twan van den; Meng, Alice; Kassam, Shaqil; Thoms, John; Bristow, Robert G.; Wouters, Bradly G.

    2011-01-01

    Background and purpose: Hypoxia is a common feature of the microenvironment of solid tumors which has been shown to promote malignancy and poor patient outcome through multiple mechanisms. The association of hypoxia with more aggressive disease may be due in part to recently identified links between hypoxia and genetic instability. For example, hypoxia has been demonstrated to impede DNA repair by down-regulating the homologous recombination protein RAD51. Here we investigated hypoxic regulation of UBE2T, a ubiquitin ligase required in the Fanconi anemia (FA) DNA repair pathway. Materials and methods: We analysed UBE2T expression by microarray, quantitative PCR and western blot analysis in a panel of cancer cell lines as a function of oxygen concentration. The importance of this regulation was assessed by measuring cell survival in response to DNA damaging agents under normoxia or hypoxia. Finally, HIF dependency was determined using knockdown cell lines and RCC4 cells which constitutively express HIF1α. Results: Hypoxia results in rapid and potent reductions in mRNA levels of UBE2T in a panel of cancer cell lines. Reduced UBE2T mRNA expression is HIF independent and was not due to changes in mRNA or protein stability, but rather reflected reduced promoter activity. Exposure of tumor cells to hypoxia greatly increased their sensitivity to treatment with the interstrand crosslinking (ICL) agent mitomycin C. Conclusions: Exposure to hypoxic conditions down-regulates UBE2T expression which correlates with an increased sensitivity to crosslinking agents consistent with a defective Fanconi anemia pathway. This pathway can potentially be exploited to target hypoxic cells in tumors.

  16. Luminal and basal-like breast cancer cells show increased migration induced by hypoxia, mediated by an autocrine mechanism

    International Nuclear Information System (INIS)

    Voss, Melanie J; Möller, Mischa F; Powe, Desmond G; Niggemann, Bernd; Zänker, Kurt S; Entschladen, Frank

    2011-01-01

    Some breast cancer patients receiving anti-angiogenic treatment show increased metastases, possibly as a result of induced hypoxia. The effect of hypoxia on tumor cell migration was assessed in selected luminal, post-EMT and basal-like breast carcinoma cell lines. Migration was assessed in luminal (MCF-7), post-EMT (MDA-MB-231, MDA-MB-435S), and basal-like (MDA-MB-468) human breast carcinoma cell lines under normal and oxygen-deprived conditions, using a collagen-based assay. Cell proliferation was determined, secreted cytokine and chemokine levels were measured using flow-cytometry and a bead-based immunoassay, and the hypoxic genes HIF-1α and CA IX were assessed using PCR. The functional effect of tumor-cell conditioned medium on the migration of neutrophil granulocytes (NG) was tested. Hypoxia caused increased migratory activity but not proliferation in all tumor cell lines, involving the release and autocrine action of soluble mediators. Conditioned medium (CM) from hypoxic cells induced migration in normoxic cells. Hypoxia changed the profile of released inflammatory mediators according to cell type. Interleukin-8 was produced only by post-EMT and basal-like cell lines, regardless of hypoxia. MCP-1 was produced by MDA-MB-435 and -468 cells, whereas IL-6 was present only in MDA-MB-231. IL-2, TNF-α, and NGF production was stimulated by hypoxia in MCF-7 cells. CM from normoxic and hypoxic MDA-MB-231 and MDA-MB-435S cells and hypoxic MCF-7 cells, but not MDA-MB-468, induced NG migration. Hypoxia increases migration by the autocrine action of released signal substances in selected luminal and basal-like breast carcinoma cell lines which might explain why anti-angiogenic treatment can worsen clinical outcome in some patients

  17. Systemic Hypoxia Changes the Organ-Specific Distribution of Vascular Endothelial Growth Factor and Its Receptors

    Science.gov (United States)

    Marti, Hugo H.; Risau, Werner

    1998-12-01

    Vascular endothelial growth factor (VEGF) plays a key role in physiological blood vessel formation and pathological angiogenesis such as tumor growth and ischemic diseases. Hypoxia is a potent inducer of VEGF in vitro. Here we demonstrate that VEGF is induced in vivo by exposing mice to systemic hypoxia. VEGF induction was highest in brain, but also occurred in kidney, testis, lung, heart, and liver. In situ hybridization analysis revealed that a distinct subset of cells within a given organ, such as glial cells and neurons in brain, tubular cells in kidney, and Sertoli cells in testis, responded to the hypoxic stimulus with an increase in VEGF expression. Surprisingly, however, other cells at sites of constitutive VEGF expression in normal adult tissues, such as epithelial cells in the choroid plexus and kidney glomeruli, decreased VEGF expression in response to the hypoxic stimulus. Furthermore, in addition to VEGF itself, expression of VEGF receptor-1 (VEGFR-1), but not VEGFR-2, was induced by hypoxia in endothelial cells of lung, heart, brain, kidney, and liver. VEGF itself was never found to be up-regulated in endothelial cells under hypoxic conditions, consistent with its paracrine action during normoxia. Our results show that the response to hypoxia in vivo is differentially regulated at the level of specific cell types or layers in certain organs. In these tissues, up- or down-regulation of VEGF and VEGFR-1 during hypoxia may influence their oxygenation after angiogenesis or modulate vascular permeability.

  18. Translational control is a major contributor to hypoxia induced gene expression

    International Nuclear Information System (INIS)

    Beucken, Twan van den; Magagnin, Michael G.; Jutten, Barry; Seigneuric, Renaud; Lambin, Philippe; Koritzinsky, Marianne; Wouters, Bradly G.

    2011-01-01

    Background and purpose: Hypoxia is a common feature of solid tumors that is associated with an aggressive phenotype, resistance to therapy and poor prognosis. Major contributors to these adverse effects are the transcriptional program activated by the HIF family of transcription factors as well as the translational response mediated by PERK-dependent phosphorylation of eIF2α and inhibition of mTORC1 activity. In this study we determined the relative contribution of both transcriptional and translational responses to changes in hypoxia induced gene expression. Material and methods: Total and efficiently translated (polysomal) mRNA was isolated from DU145 prostate carcinoma cells that were exposed for up to 24 h of hypoxia ( 2 ). Changes in transcription and translation were assessed using affymetrix microarray technology. Results: Our data reveal an unexpectedly large contribution of translation control on both induced and repressed gene expression at all hypoxic time points, particularly during acute hypoxia (2-4 h). Gene ontology analysis revealed that gene classes like transcription and signal transduction are stimulated by translational control whereas expression of genes involved in cell growth and protein metabolism are repressed during hypoxic conditions by translational control. Conclusions: Our data indicate that translation influences gene expression during hypoxia on a scale comparable to that of transcription.

  19. Identification of P450 Oxidoreductase as a Major Determinant of Sensitivity to Hypoxia-Activated Prodrugs.

    Science.gov (United States)

    Hunter, Francis W; Young, Richard J; Shalev, Zvi; Vellanki, Ravi N; Wang, Jingli; Gu, Yongchuan; Joshi, Naveen; Sreebhavan, Sreevalsan; Weinreb, Ilan; Goldstein, David P; Moffat, Jason; Ketela, Troy; Brown, Kevin R; Koritzinsky, Marianne; Solomon, Benjamin; Rischin, Danny; Wilson, William R; Wouters, Bradly G

    2015-10-01

    Hypoxia is a prevalent feature of many tumors contributing to disease progression and treatment resistance, and therefore constitutes an attractive therapeutic target. Several hypoxia-activated prodrugs (HAP) have been developed, including the phase III candidate TH-302 (evofosfamide) and the preclinical agent SN30000, which is an optimized analogue of the well-studied HAP tirapazamine. Experience with this therapeutic class highlights an urgent need to identify biomarkers of HAP sensitivity, including enzymes responsible for prodrug activation during hypoxia. Using genome-scale shRNA screens and a high-representation library enriched for oxidoreductases, we identified the flavoprotein P450 (cytochrome) oxidoreductase (POR) as the predominant determinant of sensitivity to SN30000 in three different genetic backgrounds. No other genes consistently modified SN30000 sensitivity, even within a POR-negative background. Knockdown or genetic knockout of POR reduced SN30000 reductive metabolism and clonogenic cell death and similarly reduced sensitivity to TH-302 under hypoxia. A retrospective evaluation of head and neck squamous cell carcinomas showed heterogeneous POR expression and suggested a possible relationship between human papillomavirus status and HAP sensitivity. Taken together, our study identifies POR as a potential predictive biomarker of HAP sensitivity that should be explored during the clinical development of SN30000, TH-302, and other hypoxia-directed agents. ©2015 American Association for Cancer Research.

  20. Characterization of positron emission tomography hypoxia tracer uptake and tissue oxygenation via electrochemical modeling.

    Science.gov (United States)

    Bowen, Stephen R; van der Kogel, Albert J; Nordsmark, Marianne; Bentzen, Søren M; Jeraj, Robert

    2011-08-01

    Unique uptake and retention mechanisms of positron emission tomography (PET) hypoxia tracers make in vivo comparison between them challenging. Differences in imaged uptake of two common hypoxia radiotracers, [(61)Cu]Cu-ATSM and [(18)F]FMISO, were characterized via computational modeling to address these challenges. An electrochemical formalism describing bioreductive retention mechanisms of these tracers under steady-state conditions was adopted to relate time-averaged activity concentration to tissue partial oxygen tension (PO(2)), a common metric of hypoxia. Chemical equilibrium constants of product concentration to reactant concentration ratios were determined from free energy changes and reduction potentials of pertinent reactions reported in the literature. Resulting transformation functions between tracer uptake and PO(2) were compared against measured values in preclinical models. Additionally, calculated PO(2) distributions from imaged Cu-ATSM tracer activity concentrations of 12 head and neck squamous cell carcinoma (HNSCC) patients were validated against microelectrode PO(2) measurements in 69 HNSCC patients. Both Cu-ASTM- and FMISO-modeled PO(2) transformation functions were in agreement with preclinical measured values within single-deviation confidence intervals. High correlation (r(2)=0.94, Ptracers. Comprehensive and robust assessment of tumor hypoxia prior to as well as in response to therapy may be best provided by imaging of multiple hypoxia markers that provide complementary rather than interchangeable information. Copyright © 2011 Elsevier Inc. All rights reserved.

  1. Hypoxia-targeted suicidal gene therapy system enhances antitumor effects of radiotherapy

    International Nuclear Information System (INIS)

    Liu Junye; Guo Yao; Guo Guozhen

    2006-01-01

    Objective: To explore the effects of hypoxia-targeted suicidal gene therapy system combined with radiotherapy on pancreatic cancer. Methods: The recombinant adenovirus Ad-5HRE/hCMVmp-BCD was constructed by DNA recombinant technique. Western blot was used to detect hypoxia-induced expression of bacterial cytosine deaminase (BCD). Cell growth inhibition assay was used to determine the sensitivity of human pancreatic cancer cells MIA-PACA2 to 5-fluorocytosine (5-FC). Tumor xenograft growth delay assays was used to evaluate the effects of Ad-5HRE/hCMVmp-BCD/5-FC combined with radiotherapy on pancreatic cancer. Results: Western blot analysis demonstrated that hypoxia-induced BCD protein expression was achieved in MIA-PACA2 cells infected with Ad-5HRE/hCMVmp-BCD. With hypoxia treatment, the sensitivity of MIA-PACA2 cells infected with Ad-5HRE/hCMVmp-BCD to 5-FC significantly increased. Administration of either Ad-5HRE/hCMVmp-BCD/5-FC or radiotherapy could inhibit the growth of MIA-PACA2 xenografts in nude mice. Moreover, combination of Ad-5HRE/hCMVmp-BCD/5-FC could significantly enhance suppressing effects of radiotherapy on MIA-PACA2 xenografts. Conclusion: Hypoxia-targeted suicidal gene therapy system Ad-5HRE/hCMVmp-BCD/5-FC could enhance antitumor effects of radiotherapy on pancreatic cancer and can be used as a powerful adjunct to conventional radiotherapy. (authors)

  2. Hypoxia inhibits the growth, differentiation and bone-forming capacity of rat osteoblasts

    International Nuclear Information System (INIS)

    Utting, J.C.; Robins, S.P.; Brandao-Burch, A.; Orriss, I.R.; Behar, J.; Arnett, T.R.

    2006-01-01

    We investigated the effect of hypoxia on rat osteoblast function in long-term primary cultures. Reduction of pO 2 from 20% to 5% and 2% decreased formation of mineralized bone nodules 1.7-fold and 11-fold, respectively. When pO 2 was reduced further to 0.2%, bone nodule formation was almost abolished. The inhibitory effect of hypoxia on bone formation was partly due to decreased osteoblast proliferation, as measured by 3 H-thymidine incorporation. Hypoxia also sharply reduced osteoblast alkaline phosphatase (ALP) activity and expression of mRNAs for ALP and osteocalcin, suggesting inhibition of differentiation to the osteogenic phenotype. Hypoxia did not increase the apoptosis of osteoblasts but induced a reversible state of quiescence. Transmission electron microscopy revealed that collagen fibrils deposited by osteoblasts cultured in 2% O 2 were less organized and much less abundant than in 20% O 2 cultures. Furthermore, collagen produced by hypoxic osteoblasts contained a lower percentage of hydroxylysine residues and exhibited an increased sensitivity to pepsin degradation. These data demonstrate the absolute oxygen requirement of osteoblasts for successful bone formation and emphasize the importance of the vasculature in maintaining bone health. We recently showed that hypoxia also acts in a reciprocal manner as a powerful stimulator of osteoclast formation. Considered together, our results help to explain the bone loss that occurs at the sites of fracture, tumors, inflammation and infection, and in individuals with vascular disease or anemia

  3. Mediastinal tumor

    Science.gov (United States)

    Thymoma - mediastinal; Lymphoma - mediastinal ... mediastinal tumors in adults occur in the anterior mediastinum. They are usually cancerous (malignant) lymphomas, germ cell tumors, or thymomas. These tumors are ...

  4. The regulation of transcriptional repression in hypoxia.

    Science.gov (United States)

    Cavadas, Miguel A S; Cheong, Alex; Taylor, Cormac T

    2017-07-15

    A sufficient supply molecular oxygen is essential for the maintenance of physiologic metabolism and bioenergetic homeostasis for most metazoans. For this reason, mechanisms have evolved for eukaryotic cells to adapt to conditions where oxygen demand exceeds supply (hypoxia). These mechanisms rely on the modification of pre-existing proteins, translational arrest and transcriptional changes. The hypoxia inducible factor (HIF; a master regulator of gene induction in response to hypoxia) is responsible for the majority of induced gene expression in hypoxia. However, much less is known about the mechanism(s) responsible for gene repression, an essential part of the adaptive transcriptional response. Hypoxia-induced gene repression leads to a reduction in energy demanding processes and the redirection of limited energetic resources to essential housekeeping functions. Recent developments have underscored the importance of transcriptional repressors in cellular adaptation to hypoxia. To date, at least ten distinct transcriptional repressors have been reported to demonstrate sensitivity to hypoxia. Central among these is the Repressor Element-1 Silencing Transcription factor (REST), which regulates over 200 genes. In this review, written to honor the memory and outstanding scientific legacy of Lorenz Poellinger, we provide an overview of our existing knowledge with respect to transcriptional repressors and their target genes in hypoxia. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Molecular imaging of hypoxia with radiolabelled agents

    NARCIS (Netherlands)

    Mees, Gilles; Dierckx, Rudi; Vangestel, Christel; Van de Wiele, Christophe

    2009-01-01

    Tissue hypoxia results from an inadequate supply of oxygen (O(2)) that compromises biological functions. Structural and functional abnormalities of the tumour vasculature together with altered diffusion conditions inside the tumour seem to be the main causes of tumour hypoxia. Evidence from

  6. Hypoxia: From Placental Development to Fetal Programming.