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Sample records for tumor spheroid model

  1. Fibroblast spheroids as a model to study sustained fibroblast quiescence and their crosstalk with tumor cells

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    Salmenperä, Pertteli, E-mail: pertteli.salmenpera@helsinki.fi [Department of Virology, Medicum, Faculty of Medicine, University of Helsinki, P.O. Box 21, FIN-00014 (Finland); Karhemo, Piia-Riitta [Research Programs Unit, Translational Cancer Biology, and Institute of Biomedicine, University of Helsinki, P.O. Box 63, FIN-00014 (Finland); Räsänen, Kati [Department of Virology, Medicum, Faculty of Medicine, University of Helsinki, P.O. Box 21, FIN-00014 (Finland); Laakkonen, Pirjo [Research Programs Unit, Translational Cancer Biology, and Institute of Biomedicine, University of Helsinki, P.O. Box 63, FIN-00014 (Finland); Vaheri, Antti [Department of Virology, Medicum, Faculty of Medicine, University of Helsinki, P.O. Box 21, FIN-00014 (Finland)

    2016-07-01

    Stromal fibroblasts have an important role in regulating tumor progression. Normal and quiescent fibroblasts have been shown to restrict and control cancer cell growth, while cancer-associated, i. e. activated fibroblasts have been shown to enhance proliferation and metastasis of cancer cells. In this study we describe generation of quiescent fibroblasts in multicellular spheroids and their effects on squamous cell carcinoma (SCC) growth in soft-agarose and xenograft models. Quiescent phenotype of fibroblasts was determined by global down-regulation of expression of genes related to cell cycle and increased expression of p27. Interestingly, microarray analysis showed that fibroblast quiescence was associated with similar secretory phenotype as seen in senescence and they expressed senescence-associated-β-galactosidase. Quiescent fibroblasts spheroids also restricted the growth of RT3 SCC cells both in soft-agarose and xenograft models unlike proliferating fibroblasts. Restricted tumor growth was associated with marginally increased tumor cell senescence and cellular differentiation, showed with senescence-associated-β-galactosidase and cytokeratin 7 staining. Our results show that the fibroblasts spheroids can be used as a model to study cellular quiescence and their effects on cancer cell progression. - Highlights: • Fibroblasts acquire a sustained quiescence when grown as multicellular spheroids. • This quiescence is associated with drastic change in gene expression. • Fibroblasts spheroids secrete various inflammation-linked cytokines and chemokines. • Fibroblasts spheroids reduced growth of RT3 SCC cells in xenograft model.

  2. Multicellular spheroids as an in vitro tumor model

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    Kozubek, S.; Erzgraber, G.

    1982-01-01

    Experiments with fractionated irradiation of multicellular spheroids were performed. Our data as well as the data of other works have been evaluated by means of simple mathematical formulae on the basis of several hypothesis. The spheroids are shown to exhibit similar behaviour as in vivo carcinomas. They offer the possibility of investigation of quantitative correlations for practical purposes

  3. Emerging tumor spheroids technologies for 3D in vitro cancer modeling.

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    Rodrigues, Tânia; Kundu, Banani; Silva-Correia, Joana; Kundu, S C; Oliveira, Joaquim M; Reis, Rui L; Correlo, Vitor M

    2018-04-01

    Cancer is a leading cause of mortality and morbidity worldwide. Around 90% of deaths are caused by metastasis and just 10% by primary tumor. The advancement of treatment approaches is not at the same rhythm of the disease; making cancer a focal target of biomedical research. To enhance the understanding and prompts the therapeutic delivery; concepts of tissue engineering are applied in the development of in vitro models that can bridge between 2D cell culture and animal models, mimicking tissue microenvironment. Tumor spheroid represents highly suitable 3D organoid-like framework elucidating the intra and inter cellular signaling of cancer, like that formed in physiological niche. However, spheroids are of limited value in studying critical biological phenomenon such as tumor-stroma interactions involving extra cellular matrix or immune system. Therefore, a compelling need of tailoring spheroid technologies with physiologically relevant biomaterials or in silico models, is ever emerging. The diagnostic and prognostic role of spheroids rearrangements within biomaterials or microfluidic channel is indicative of patient management; particularly for the decision of targeted therapy. Fragmented information on available in vitro spheroid models and lack of critical analysis on transformation aspects of these strategies; pushes the urge to comprehensively overview the recent technological advancements (e.g. bioprinting, micro-fluidic technologies or use of biomaterials to attain the third dimension) in the shed of translationable cancer research. In present article, relationships between current models and their possible exploitation in clinical success is explored with the highlight of existing challenges in defining therapeutic targets and screening of drug efficacy. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Fibroblast spheroids as a model to study sustained fibroblast quiescence and their crosstalk with tumor cells.

    Science.gov (United States)

    Salmenperä, Pertteli; Karhemo, Piia-Riitta; Räsänen, Kati; Laakkonen, Pirjo; Vaheri, Antti

    2016-07-01

    Stromal fibroblasts have an important role in regulating tumor progression. Normal and quiescent fibroblasts have been shown to restrict and control cancer cell growth, while cancer-associated, i. e. activated fibroblasts have been shown to enhance proliferation and metastasis of cancer cells. In this study we describe generation of quiescent fibroblasts in multicellular spheroids and their effects on squamous cell carcinoma (SCC) growth in soft-agarose and xenograft models. Quiescent phenotype of fibroblasts was determined by global down-regulation of expression of genes related to cell cycle and increased expression of p27. Interestingly, microarray analysis showed that fibroblast quiescence was associated with similar secretory phenotype as seen in senescence and they expressed senescence-associated-β-galactosidase. Quiescent fibroblasts spheroids also restricted the growth of RT3 SCC cells both in soft-agarose and xenograft models unlike proliferating fibroblasts. Restricted tumor growth was associated with marginally increased tumor cell senescence and cellular differentiation, showed with senescence-associated-β-galactosidase and cytokeratin 7 staining. Our results show that the fibroblasts spheroids can be used as a model to study cellular quiescence and their effects on cancer cell progression. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Cisplatin Resistant Spheroids Model Clinically Relevant Survival Mechanisms in Ovarian Tumors.

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    Winyoo Chowanadisai

    Full Text Available The majority of ovarian tumors eventually recur in a drug resistant form. Using cisplatin sensitive and resistant cell lines assembled into 3D spheroids we profiled gene expression and identified candidate mechanisms and biological pathways associated with cisplatin resistance. OVCAR-8 human ovarian carcinoma cells were exposed to sub-lethal concentrations of cisplatin to create a matched cisplatin-resistant cell line, OVCAR-8R. Genome-wide gene expression profiling of sensitive and resistant ovarian cancer spheroids identified 3,331 significantly differentially expressed probesets coding for 3,139 distinct protein-coding genes (Fc >2, FDR < 0.05 (S2 Table. Despite significant expression changes in some transporters including MDR1, cisplatin resistance was not associated with differences in intracellular cisplatin concentration. Cisplatin resistant cells were significantly enriched for a mesenchymal gene expression signature. OVCAR-8R resistance derived gene sets were significantly more biased to patients with shorter survival. From the most differentially expressed genes, we derived a 17-gene expression signature that identifies ovarian cancer patients with shorter overall survival in three independent datasets. We propose that the use of cisplatin resistant cell lines in 3D spheroid models is a viable approach to gain insight into resistance mechanisms relevant to ovarian tumors in patients. Our data support the emerging concept that ovarian cancers can acquire drug resistance through an epithelial-to-mesenchymal transition.

  6. Tumor penetration with intact MAb and fragments demonstrated in vitro on tumor spheroids and in vivo in the nude mouse model

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    Buchegger, F.; Halpern, S.E.; Sutherland, R.M.; Schreyer, M.; Mach, J.P.

    1986-01-01

    Tumor spheroids grown in culture represent a good in vitro model for the study of tumor penetration phenomena of potential radiotherapeutics. Using this system, it was found that Fab-fragments penetrate tumors more quickly and deeply than complete antibodies. These results were confirmed in tumor bearing nephrectomized nude mice

  7. [Spheroids: A reference model for in vitro culture of solid tumors?

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    Larsen, Christian-Jacques

    2018-01-01

    The recognition that solid tumors are complex entities composed of the tumor cell mass itself and a stromal micro-environnement providing a variety of cells from the host (fibroblasts, endothelial cells, immune cells) led to recognize that this heterogeneity could not be recapitulated in vitro by conventional bidimensional (2-D) cultures. This justified numerous attempts to develop tridimensional (3-D) cultures that provided better tools for approaching tumor complexity and more convincing drug testing systems. Among various 3-D technologies, tumor spheroids are more likely suited to provide in vitro platforms for apprehending specific aspects of different processes specifically defining each tumor category as well as testing drug delivery systems. This review summarizes current features of multicellular tumor spheroids and their suitability for studying different aspects of cancer cell biology, patient-specific therapies and drug treatment. Copyright © 2017 Société Française du Cancer. Published by Elsevier Masson SAS. All rights reserved.

  8. Drug delivery to solid tumors: the predictive value of the multicellular tumor spheroid model for nanomedicine screening

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    Millard M

    2017-10-01

    Full Text Available Marie Millard,1,2 Ilya Yakavets,1–3 Vladimir Zorin,3,4 Aigul Kulmukhamedova,1,2,5 Sophie Marchal,1,2 Lina Bezdetnaya1,2 1Centre de Recherche en Automatique de Nancy, Centre National de la Recherche Scientifique UMR 7039, Université de Lorraine, 2Research Department, Institut de Cancérologie de Lorraine, Vandœuvre-lès-Nancy, France; 3Laboratory of Biophysics and Biotechnology, 4International Sakharov Environmental Institute, Belarusian State University, Minsk, Belarus; 5Department of Radiology, Medical Company Sunkar, Almaty, Kazakhstan Abstract: The increasing number of publications on the subject shows that nanomedicine is an attractive field for investigations aiming to considerably improve anticancer chemotherapy. Based on selective tumor targeting while sparing healthy tissue, carrier-mediated drug delivery has been expected to provide significant benefits to patients. However, despite reduced systemic toxicity, most nanodrugs approved for clinical use have been less effective than previously anticipated. The gap between experimental results and clinical outcomes demonstrates the necessity to perform comprehensive drug screening by using powerful preclinical models. In this context, in vitro three-dimensional models can provide key information on drug behavior inside the tumor tissue. The multicellular tumor spheroid (MCTS model closely mimics a small avascular tumor with the presence of proliferative cells surrounding quiescent cells and a necrotic core. Oxygen, pH and nutrient gradients are similar to those of solid tumor. Furthermore, extracellular matrix (ECM components and stromal cells can be embedded in the most sophisticated spheroid design. All these elements together with the physicochemical properties of nanoparticles (NPs play a key role in drug transport, and therefore, the MCTS model is appropriate to assess the ability of NP to penetrate the tumor tissue. This review presents recent developments in MCTS models for a

  9. Differential thermo-resistance of multicellular tumor spheroids

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    Khoei, S.; Goliaei, B.; Neshasteh-Rize, A.

    2004-01-01

    Many cell lines, when cultured under proper conditions, can form three dimensional structures called multicellular spheroids. These spheroids resemble in vivo tumor models in several aspects. Therefore, studying growth characteristics and behavior of spheroids is beneficial in understanding the behavior of tumors under various experimental conditions. In this work, we have studied the growth properties, along with the thermal characteristics of spheroids of Du 145 human prostate carcinoma cell lines and compared the results to monolayer cultures of these cells. For this purpose, The Du 145 cells were cultured either as monolayer or spheroids. At various times after initiation of cultures, the growth properties of spheroids as a function of seeding cell number was determined. To evaluate the thermal characteristics of spheroids, they were heated at various stages of growth at 43 d ig c for various periods. The thermal response was judged by the survival fraction of colony forming cells in spheroids or monolayer culture following heat treatment. The results showed spheroids were more resistant to heat than monolayer cultures at all stages of development. However, the extent of this thermal resistant was dependent on the age, and consequently, the size of the spheroid. The result suggests that the differential thermal resistance of the spheroid cultures develop gradually during the growth of spheroid cultures of Du 145 cell line

  10. Mass Spectrometry Analyses of Multicellular Tumor Spheroids.

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    Acland, Mitchell; Mittal, Parul; Lokman, Noor A; Klingler-Hoffmann, Manuela; Oehler, Martin K; Hoffmann, Peter

    2017-12-11

    Multicellular tumor spheroids (MCTS) are a powerful biological in vitro model, which closely mimics the 3D structure of primary avascularized tumors. Mass spectrometry (MS) has established itself as a powerful analytical tool, not only to better understand and describe the complex structure of MCTS, but also to monitor their response to cancer therapeutics. The first part of this review focuses on traditional mass spectrometry approaches with an emphasis on elucidating the molecular characteristics of these structures. Then the mass spectrometry imaging (MSI) approaches used to obtain spatially defined information from MCTS is described. Finally the analysis of primary spheroids, such as those present in ovarian cancer, and the great potential that mass spectrometry analysis of these structures has for improved understanding of cancer progression and for personalized in vitro therapeutic testing is discussed. © 2017 The Authors. PROTEOMICS - Clinical Applications Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Inhibition of hexokinase-2 with targeted liposomal 3-bromopyruvate in an ovarian tumor spheroid model of aerobic glycolysis

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    Gandham SK

    2015-07-01

    Full Text Available Srujan Kumar Gandham, Meghna Talekar, Amit Singh, Mansoor M Amiji Department of Pharmaceutical Sciences, School of Pharmacy, Northeastern University, Boston, MA, USA Background: The objective of this study was to evaluate the expression levels of glycolytic markers, especially hexokinase-2 (HK2, using a three-dimensional multicellular spheroid model of human ovarian adenocarcinoma (SKOV-3 cells and to develop an epidermal growth factor receptor-targeted liposomal formulation for improving inhibition of HK2 and the cytotoxicity of 3-bromopyruvate (3-BPA. Methods: Multicellular SKOV-3 tumor spheroids were developed using the hanging drop method and expression levels of glycolytic markers were examined. Non-targeted and epidermal growth factor receptor-targeted liposomal formulations of 3-BPA were formulated and characterized. Permeability and cellular uptake of the liposomal formulations in three-dimensional SKOV-3 spheroids was evaluated using confocal microscopy. The cytotoxicity and HK2 inhibition potential of solution form of 3-BPA was compared to the corresponding liposomal formulation by using cell proliferation and HK2 enzymatic assays. Results: SKOV-3 spheroids were reproducibly developed using the 96-well hanging drop method, with an average size of 900 µm by day 5. HK2 enzyme activity levels under hypoxic conditions were found to be higher than under normoxic conditions (P<0.0001, Student’s t-test, unpaired and two-tailed. Liposomal formulations (both non-targeted and targeted of 3-BPA showed a more potent inhibitory effect (P<0.001, Student’s t-test, unpaired and two-tailed at a dose of 50 µM than the aqueous solution form at 3, 6, and 24 hours post administration. Similarly, the cytotoxic activity 3-BPA at various concentrations (10 µM–100 µM showed that the liposomal formulations had an enhanced cytotoxic effect of 2–5-fold (P<0.0001, Student’s t-test, unpaired and two-tailed when compared to the aqueous solution form

  12. Co-culture of 3D tumor spheroids with fibroblasts as a model for epithelial–mesenchymal transition in vitro

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    Kim, Sun-Ah, E-mail: j.sarah.k@gmail.com [Department of Biomedicine & Health Sciences, College of Medicine, The Catholic University of Korea, Seoul 137-701 (Korea, Republic of); Lee, Eun Kyung, E-mail: leeek@catholic.ac.kr [Department of Biochemistry, College of Medicine, The Catholic University of Korea, Seoul 137-701 (Korea, Republic of); Cancer Evolution Research Center, College of Medicine, The Catholic University of Korea, Seoul 137-701 (Korea, Republic of); Kuh, Hyo-Jeong, E-mail: hkuh@catholic.ac.kr [Department of Biomedicine & Health Sciences, College of Medicine, The Catholic University of Korea, Seoul 137-701 (Korea, Republic of); Cancer Evolution Research Center, College of Medicine, The Catholic University of Korea, Seoul 137-701 (Korea, Republic of)

    2015-07-15

    Epithelial–mesenchymal transition (EMT) acts as a facilitator of metastatic dissemination in the invasive margin of malignant tumors where active tumor–stromal crosstalks take place. Co-cultures of cancer cells with cancer-associated fibroblasts (CAFs) are often used as in vitro models of EMT. We established a tumor–fibroblast proximity co-culture using HT-29 tumor spheroids (TSs) with CCD-18co fibroblasts. When co-cultured with TSs, CCD-18co appeared activated, and proliferative activity as well as cell migration increased. Expression of fibronectin increased whereas laminin and type I collagen decreased in TSs co-cultured with fibroblasts compared to TSs alone, closely resembling the margin of in vivo xenograft tissue. Active TGFβ1 in culture media significantly increased in TS co-cultures but not in 2D co-cultures of cancer cells–fibroblasts, indicating that 3D context-associated factors from TSs may be crucial to crosstalks between cancer cells and fibroblasts. We also observed in TSs co-cultured with fibroblasts increased expression of α-SMA, EGFR and CTGF; reduced expression of membranous β-catenin and E-cadherin, together suggesting an EMT-like changes similar to a marginal region of xenograft tissue in vivo. Overall, our in vitro TS–fibroblast proximity co-culture mimics the EMT-state of the invasive margin of in vivo tumors in early metastasis. - Highlights: • An adjacent co-culture of tumor spheroids and fibroblasts is presented as EMT model. • Activation of fibroblasts and increased cell migration were shown in co-culture. • Expression of EMT-related factors in co-culture was similar to that in tumor tissue. • Crosstalk between spheroids and fibroblasts was demonstrated by secretome analysis.

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

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    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.

  14. Coadministration of a tumor-penetrating peptide improves the therapeutic efficacy of paclitaxel in a novel air-grown lung cancer 3D spheroid model.

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    Gupta, Sweta K; Torrico Guzmán, Elisa A; Meenach, Samantha A

    2017-11-15

    Three-dimensional (3 D) cell culture platforms are increasingly being used in cancer research and drug development since they mimic avascular tumors in vitro. In this study, we focused on the development of a novel air-grown multicellular spheroid (MCS) model to mimic in vivo tumors for understanding lung cancer biology and improvement in the evaluation of aerosol anticancer therapeutics. 3 D MCS were formed using A549 lung adenocarcinoma cells, comprising cellular heterogeneity with respect to different proliferative and metabolic gradients. The growth kinetics, morphology and 3 D structure of air-grown MCS were characterized by brightfield, fluorescent and scanning electron microscopy. MCS demonstrated a significant decrease in growth when the tumor-penetrating peptide iRGD and paclitaxel (PTX) were coadministered as compared with PTX alone. It was also found that when treated with both iRGD and PTX, A549 MCS exhibited an increase in apoptosis and decrease in clonogenic survival capacity in contrast to PTX treatment alone. This study demonstrated that coadministration of iRGD resulted in the improvement of the tumor penetration ability of PTX in an in vitro A549 3 D MCS model. In addition, this is the first time a high-throughput air-grown lung cancer tumor spheroid model has been developed and evaluated. © 2017 UICC.

  15. Developing multi-cellular tumor spheroid model (MCTS) in the chitosan/collagen/alginate (CCA) fibrous scaffold for anticancer drug screening

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    Wang, Jian-Zheng, E-mail: wppzheng@126.com [Laboratory of Biomedical Material Engineering, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023 (China); Affiliated General Hospital, Tianguan Group Co., Ltd, Nanyang 473000 (China); Testing Center of Henan Tianguan Group Co., Ltd, Nanyang 473000 (China); Zhu, Yu-Xia [Laboratory of Biomedical Material Engineering, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023 (China); Affiliated General Hospital, Tianguan Group Co., Ltd, Nanyang 473000 (China); Testing Center of Henan Tianguan Group Co., Ltd, Nanyang 473000 (China); Ma, Hui-Chao; Chen, Si-Nan; Chao, Ji-Ye; Ruan, Wen-Ding; Wang, Duo; Du, Feng-guang [Affiliated General Hospital, Tianguan Group Co., Ltd, Nanyang 473000 (China); Testing Center of Henan Tianguan Group Co., Ltd, Nanyang 473000 (China); Meng, Yue-Zhong [State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275 (China)

    2016-05-01

    In this work, a 3D MCTS-CCA system was constructed by culturing multi-cellular tumor spheroid (MCTS) in the chitosan/collagen/alginate (CCA) fibrous scaffold for anticancer drug screening. The CCA scaffolds were fabricated by spray-spinning. The interactions between the components of the spray-spun fibers were evidenced by methods of Coomassie Blue stain, X-ray diffraction (XRD) and Fourier transform-infrared spectroscopy (FTIR). Co-culture indicated that MCF-7 cells showed a spatial growth pattern of multi-cellular tumor spheroid (MCTS) in the CCA fibrous scaffold with increased proliferation rate and drug-resistance to MMC, ADM and 5-Aza comparing with the 2D culture cells. Significant increases of total viable cells were found in 3D MCTS groups after drug administration by method of apoptotic analysis. Glucose–lactate analysis indicated that the metabolism of MCTS in CCA scaffold was closer to the tumor issue in vivo than the monolayer cells. In addition, MCTS showed the characteristic of epithelial mesenchymal transition (EMT) which is subverted by carcinoma cells to facilitate metastatic spread. These results demonstrated that MCTS in CCA scaffold possessed a more conservative phenotype of tumor than monolayer cells, and anticancer drug screening in 3D MCTS-CCA system might be superior to the 2D culture system. - Highlights: • Chitosan/collagen/alginate (CCA) scaffolds were fabricated by spray-spinning. • MCF-7 cells presented a multi-cellular tumor spheroid model (MCTS) in CCA scaffold. • MCTS in CCA possessed a more conservative phenotype of tumor than monolayer cells. • Anticancer drug screening in MCTS-CCA system is superior to 2D culture system.

  16. Engineered Breast Cancer Cell Spheroids Reproduce Biologic Properties of Solid Tumors.

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    Ham, Stephanie L; Joshi, Ramila; Luker, Gary D; Tavana, Hossein

    2016-11-01

    Solid tumors develop as 3D tissue constructs. As tumors grow larger, spatial gradients of nutrients and oxygen and inadequate diffusive supply to cells distant from vasculature develops. Hypoxia initiates signaling and transcriptional alterations to promote survival of cancer cells and generation of cancer stem cells (CSCs) that have self-renewal and tumor-initiation capabilities. Both hypoxia and CSCs are associated with resistance to therapies and tumor relapse. This study demonstrates that 3D cancer cell models, known as tumor spheroids, generated with a polymeric aqueous two-phase system (ATPS) technology capture these important biological processes. Similar to solid tumors, spheroids of triple negative breast cancer cells deposit major extracellular matrix proteins. The molecular analysis establishes presence of hypoxic cells in the core region and expression of CSC gene and protein markers including CD24, CD133, and Nanog. Importantly, these spheroids resist treatment with chemotherapy drugs. A combination treatment approach using a hypoxia-activated prodrug, TH-302, and a chemotherapy drug, doxorubicin, successfully targets drug resistant spheroids. This study demonstrates that ATPS spheroids recapitulate important biological and functional properties of solid tumors and provide a unique model for studies in cancer research. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Drug testing and flow cytometry analysis on a large number of uniform sized tumor spheroids using a microfluidic device

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    Patra, Bishnubrata; Peng, Chien-Chung; Liao, Wei-Hao; Lee, Chau-Hwang; Tung, Yi-Chung

    2016-02-01

    Three-dimensional (3D) tumor spheroid possesses great potential as an in vitro model to improve predictive capacity for pre-clinical drug testing. In this paper, we combine advantages of flow cytometry and microfluidics to perform drug testing and analysis on a large number (5000) of uniform sized tumor spheroids. The spheroids are formed, cultured, and treated with drugs inside a microfluidic device. The spheroids can then be harvested from the device without tedious operation. Due to the ample cell numbers, the spheroids can be dissociated into single cells for flow cytometry analysis. Flow cytometry provides statistical information in single cell resolution that makes it feasible to better investigate drug functions on the cells in more in vivo-like 3D formation. In the experiments, human hepatocellular carcinoma cells (HepG2) are exploited to form tumor spheroids within the microfluidic device, and three anti-cancer drugs: Cisplatin, Resveratrol, and Tirapazamine (TPZ), and their combinations are tested on the tumor spheroids with two different sizes. The experimental results suggest the cell culture format (2D monolayer vs. 3D spheroid) and spheroid size play critical roles in drug responses, and also demonstrate the advantages of bridging the two techniques in pharmaceutical drug screening applications.

  18. Improved Methods to Generate Spheroid Cultures from Tumor Cells, Tumor Cells & Fibroblasts or Tumor-Fragments: Microenvironment, Microvesicles and MiRNA.

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    Zheng Lao

    Full Text Available Diagnostic and prognostic indicators are key components to achieve the goal of personalized cancer therapy. Two distinct approaches to this goal include predicting response by genetic analysis and direct testing of possible therapies using cultures derived from biopsy specimens. Optimally, the latter method requires a rapid assessment, but growing xenograft tumors or developing patient-derived cell lines can involve a great deal of time and expense. Furthermore, tumor cells have much different responses when grown in 2D versus 3D tissue environments. Using a modification of existing methods, we show that it is possible to make tumor-fragment (TF spheroids in only 2-3 days. TF spheroids appear to closely model characteristics of the original tumor and may be used to assess critical therapy-modulating features of the microenvironment such as hypoxia. A similar method allows the reproducible development of spheroids from mixed tumor cells and fibroblasts (mixed-cell spheroids. Prior literature reports have shown highly variable development and properties of mixed-cell spheroids and this has hampered the detailed study of how individual tumor-cell components interact. In this study, we illustrate this approach and describe similarities and differences using two tumor models (U87 glioma and SQ20B squamous-cell carcinoma with supporting data from additional cell lines. We show that U87 and SQ20B spheroids predict a key microenvironmental factor in tumors (hypoxia and that SQ20B cells and spheroids generate similar numbers of microvesicles. We also present pilot data for miRNA expression under conditions of cells, tumors, and TF spheroids.

  19. Comparison of intratumoral FDG and Cu-ATSM distributions in cancer tissue originated spheroid (CTOS) xenografts, a tumor model retaining the original tumor properties

    International Nuclear Information System (INIS)

    Furukawa, Takako; Yuan, Qinghua; Jin, Zhao-Hui; Aung, Winn; Yoshii, Yukie; Hasegawa, Sumitaka; Endo, Hiroko; Inoue, Masahiro; Zhang, Ming-Rong; Fujibayashi, Yasuhisa; Saga, Tsuneo

    2014-01-01

    Introduction: The intratumoral distributions of [ 18 F]FDG and [ 64 Cu]Cu-ATSM have been reported to be similar in adenocarcinomas but different in squamous cell carcinoma (SCC) in clinical studies. In the present study, we compared the intratumoral distributions of these two tracers in cancer tissue originated spheroid (CTOS) xenografts derived from adenocarcinoma and SCC, which retain the histological characteristics of the original tumors, and in cancer cell line xenografts of corresponding origin, to investigate the underlying mechanism of the distinct FDG and Cu-ATSM distribution patterns in adenocarcinoma and SCC. Methods: CTOSs derived from colon adenocarcinoma and lung SCC and cell lines established from colon adenocarcinoma and lung SCC, which were used for comparison, were subcutaneously transplanted into immunodeficient mice. One hour after administering [ 14 C]FDG and [ 64 Cu]Cu-ATSM, the intratumoral distributions were compared in the xenografts by using dual-tracer autoradiography. Adjacent sections were evaluated for necrosis, vasculature anatomy, Ki-67 antigen, and pimonidazole adducts using hematoxylin and eosin and immunohistochemical staining. Results: There was a higher regional overlap of high FDG and Cu-ATSM accumulations in the adenocarcinoma CTOS xenografts than in the SCC CTOS xenografts, while the overlap in the adenocarcinoma cell line xenograft was lower than that observed in the SCC cell line. High FDG accumulation occurred primarily in proximity to necrotic or pimonidazole adduct positive regions, while high Cu-ATSM accumulation occurred primarily in live cell regions separate from the necrotic regions. The adenocarcinoma CTOS xenograft had the stereotypical glandular structure, resulting in more intricately mixed regions of live and necrotic cells compared to those observed in the SCC CTOS or the cell line xenografts. Conclusion: Tumor morphological characteristics, specifically the spatial distribution of live and necrotic cell

  20. Elemental mapping by synchrotron radiation X-Ray microfluorescence in cellular spheroid of prostate tumor cells

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    Leitao, R.G.; Anjos, M.J.; Lopes, R.T., E-mail: roberta@lin.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Lab. de Instrumentacao Nuclear; Santos, C.A.N. [Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMETRO), Duque de Caxias, RJ (Brazil). Lab. de Biotecnologia; Palumbo Junior, A.; Souza, P.A.V.R.; Nasciutti, L.E. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Instituto de Ciencias Biomedicas; Pereira, G.R. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Lab. de Ensaios Nao Destrutivos, Corrosao e Soldagem

    2013-08-15

    Prostate cancer is the sixth most common type of cancer and the third most common in males in Western industrialized countries. Cellular spheroid serves as excellent physiologic tumor models as they mimic avascular tumors and micrometastases. Trace elements play a significant role in biological processes. They are capable of affecting human health by competing with essential elements for available binding sites and by the activation or inhibition of reactions between metabolic enzymes. It is well known that zinc levels in the peripheral zone of dorsal and lateral lobes of the prostate are almost 10 times higher than in other soft tissues. Prostate tumor cells were isolated of the prostate tissue samples that were collected from patients submitted to surgery. The measurements were performed in XRF beam line at the Synchrotron Light National Laboratory (LNLS) in Campinas, Brazil. The results showed that all elements were heterogeneously distributed in different areas of the spheroids analyzed. P, S and Cl showed similar elemental distribution in all the samples analyzed while K, Ca, Fe, and Cu showed different elemental distribution. In all spheroids analyzed, Zn presented more intense distributions in the central region of the spheroid. The relationship between the function of Zn in the secretory epithelial cells and the carcinogenic process suggests that more studies on elemental mapping in spheroids are necessary. (author)

  1. Establishment and characterization of multicellular spheroids from a human glioma cell line; Implications for tumor therapy

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    Arya MB

    2006-03-01

    Full Text Available Abstract Background Multicellular spheroids, an appropriate in vitro system for simulating 3-D tumor micro-milieu can be used for evaluating and predicting tumor response to therapeutic agents including metabolic inhibitors. However, detailed understanding of the nature, distribution and sensitivity/responses of cellular sub-populations to potential therapeutic agents/strategies is required for using this unique model with optimal precision. Spheroid characteristics may also vary considerably with the origin and type of cell line used, and thorough characterization of viable and dissociated glioma cell spheroids is not yet completely known. In order to evaluate in vivo responses of gliomas to various therapeutic strategies, especially the metabolic inhibitors capable of penetrating the blood brain barrier, we have characterized continuously growing spheroids of a human glioma cell line (BMG-1 with respect to organization, growth, viability, cell survival, cell death, metabolic and mitochondrial status, oxidative stress and radiation response using microscopy, flow cytometry and enzymatic assays. Spheroids were fed daily with fresh medium in order to maintain nutrient supply to outer cellular layers while hypoxia/necrosis developed in the innermost cells of enlarging spheroids. Results Volume of spheroids, fed daily with fresh medium, increased exponentially during 7–28 days of growth through three population doublings. Proportion of G1-phase cells was higher (~60% than exponentially growing monolayer cells (~48%. A significant fraction of S-phase cells turned metabolically inactive (disengaged in DNA synthesis with increasing age of the spheroids, unlike in quiescent monolayer cultures, where the fraction of S-phase cells was less than 5%. With increasing spheroid size, increasing sub-populations of cells became non-viable and entered apoptosis or necrosis revealed by Annexin-V-FITC/PI staining. PI positive (necrotic cells were not confined to

  2. Homogeneous pancreatic cancer spheroids mimic growth pattern of circulating tumor cell clusters and macrometastases: displaying heterogeneity and crater-like structure on inner layer.

    Science.gov (United States)

    Feng, Hao; Ou, Bao-Chi; Zhao, Jing-Kun; Yin, Shuai; Lu, Ai-Guo; Oechsle, Eva; Thasler, Wolfgang E

    2017-09-01

    Pancreatic cancer 3D in vitro models including multicellular tumor spheroid (MCTS), single cell-derived tumor spheroid (SCTS), tissue-derived tumor spheroid, and organotypic models provided powerful platforms to mimic in vivo tumor. Recent work supports that circulating tumor cell (CTC) clusters are more efficient in metastasis seeding than single CTCs. The purpose of this study is to establish 3D culture models which can mimic single CTC, monoclonal CTC clusters, and the expansion of macrometastases. Seven pancreatic ductal adenocarcinoma cell lines were used to establish MCTS and SCTS using hanging drop and ultra-low attachment plates. Spheroid immunofluorescence staining, spheroid formation assay, immunoblotting, and literature review were performed to investigate molecular biomarkers and the morphological characteristics of pancreatic tumor spheroids. Single cells experienced different growth patterns to form SCTS, like signet ring-like cells, blastula-like structures, and solid core spheroids. However, golf ball-like hollow spheroids could also be detected, especially when DanG and Capan-1 cells were cultivated with fibroblast-conditioned medium (p cell lines could also establish tumor spheroid with hanging drop plates by adding methylated cellulose. Tumor spheroids derived from pancreatic cancer cell line DanG possessed asymmetrically distributed proliferation center, immune-checkpoint properties. ß-catenin, Ki-67, and F-actin were active surrounding the crater-like structure distributing on the inner layer of viable rim cover of the spheroids, which was relevant to well-differentiated tumor cells. It is possible to establish 3D CTC cluster models from homogenous PDA cell lines using hanging drop and ultra-low attachment plates. PDA cell line displays its own intrinsic properties or heterogeneity. The mechanism of formation of the crater-like structure as well as golf ball-like structure needs further exploration.

  3. High-throughput image analysis of tumor spheroids: a user-friendly software application to measure the size of spheroids automatically and accurately.

    Science.gov (United States)

    Chen, Wenjin; Wong, Chung; Vosburgh, Evan; Levine, Arnold J; Foran, David J; Xu, Eugenia Y

    2014-07-08

    The increasing number of applications of three-dimensional (3D) tumor spheroids as an in vitro model for drug discovery requires their adaptation to large-scale screening formats in every step of a drug screen, including large-scale image analysis. Currently there is no ready-to-use and free image analysis software to meet this large-scale format. Most existing methods involve manually drawing the length and width of the imaged 3D spheroids, which is a tedious and time-consuming process. This study presents a high-throughput image analysis software application - SpheroidSizer, which measures the major and minor axial length of the imaged 3D tumor spheroids automatically and accurately; calculates the volume of each individual 3D tumor spheroid; then outputs the results in two different forms in spreadsheets for easy manipulations in the subsequent data analysis. The main advantage of this software is its powerful image analysis application that is adapted for large numbers of images. It provides high-throughput computation and quality-control workflow. The estimated time to process 1,000 images is about 15 min on a minimally configured laptop, or around 1 min on a multi-core performance workstation. The graphical user interface (GUI) is also designed for easy quality control, and users can manually override the computer results. The key method used in this software is adapted from the active contour algorithm, also known as Snakes, which is especially suitable for images with uneven illumination and noisy background that often plagues automated imaging processing in high-throughput screens. The complimentary "Manual Initialize" and "Hand Draw" tools provide the flexibility to SpheroidSizer in dealing with various types of spheroids and diverse quality images. This high-throughput image analysis software remarkably reduces labor and speeds up the analysis process. Implementing this software is beneficial for 3D tumor spheroids to become a routine in vitro model

  4. Surface chemistry-mediated penetration and gold nanorod thermotherapy in multicellular tumor spheroids

    Science.gov (United States)

    Jin, Shubin; Ma, Xiaowei; Ma, Huili; Zheng, Kaiyuan; Liu, Juan; Hou, Shuai; Meng, Jie; Wang, Paul C.; Wu, Xiaochun; Liang, Xing-Jie

    2012-12-01

    We investigated the penetration and thermotherapy efficiency of different surface coated gold nanorods (Au NRs) in multicellular tumor spheroids. The current data show that negatively charged Au NRs, other than positively charged Au NRs, can penetrate deep into the tumor spheroids and achieve a significant thermal therapeutic benefit.We investigated the penetration and thermotherapy efficiency of different surface coated gold nanorods (Au NRs) in multicellular tumor spheroids. The current data show that negatively charged Au NRs, other than positively charged Au NRs, can penetrate deep into the tumor spheroids and achieve a significant thermal therapeutic benefit. Electronic supplementary information (ESI) available: Materials and methods section. See DOI: 10.1039/c2nr31877f

  5. Evaluation of anti-HER2 scFv-conjugated PLGA–PEG nanoparticles on 3D tumor spheroids of BT474 and HCT116 cancer cells

    International Nuclear Information System (INIS)

    Le, Thi Thuy Duong; Pham, Thu Hong; Ngo, Thi Hong Giang; Le, Quang Huan; Nguyen, Trong Nghia; Hoang, Thi My Nhung

    2016-01-01

    Three-dimensional culture cells (spheroids) are one of the multicellular culture models that can be applied to anticancer chemotherapeutic development. Multicellular spheroids more closely mimic in vivo tumor-like patterns of physiologic environment and morphology. In previous research, we designed docetaxel-loaded pegylated poly(D, L-lactide-co-glycolide) nanoparticles conjugated with anti-HER2 single chain antibodies (scFv–Doc–PLGA–PEG) and evaluated them in 2D cell culture. In this study, we continuously evaluate the cellular uptake and cytotoxic effect of scFv–Doc–PLGA–PEG on a 3D tumor spheroid model of BT474 (HER2-overexpressing) and HCT116 (HER2-underexpressing) cancer cells. The results showed that the nanoparticle formulation conjugated with scFv had a significant internalization effect on the spheroids of HER2-overexpressing cancer cells as compared to the spheroids of HER2-underexpressing cancer cells. Therefore, cytotoxic effects of targeted nanoparticles decreased the size and increased necrotic score of HER2-overexpressing tumor spheroids. Thus, these scFv–Doc–PLGA–PEG nanoparticles have potential for active targeting for HER2-overexpressing cancer therapy. In addition, BT474 and HCT116 spheroids can be used as a tumor model for evaluation of targeting therapies. (paper)

  6. Radiosensitivity of different human tumor cells lines grown as multicellular spheroids determined from growth curves and survival data

    International Nuclear Information System (INIS)

    Schwachoefer, J.H.C.; Crooijmans, R.P.; van Gasteren, J.J.; Hoogenhout, J.; Jerusalem, C.R.; Kal, H.B.; Theeuwes, A.G.

    1989-01-01

    Five human tumor cell lines were grown as multicellular tumor spheroids (MTS) to determine whether multicellular tumor spheroids derived from different types of tumors would show tumor-type dependent differences in response to single-dose irradiation, and whether these differences paralleled clinical behavior. Multicellular tumor spheroids of two neuroblastoma, one lung adenocarcinoma, one melanoma, and a squamous cell carcinoma of the oral tongue, were studied in terms of growth delay, calculated cell survival, and spheroid control dose50 (SCD50). Growth delay and cell survival analysis for the tumor cell lines showed sensitivities that correlated well with clinical behavior of the tumor types of origin. Similar to other studies on melanoma multicellular tumor spheroids our spheroid control dose50 results for the melanoma cell line deviated from the general pattern of sensitivity. This might be due to the location of surviving cells, which prohibits proliferation of surviving cells and hence growth of melanoma multicellular tumor spheroids. This study demonstrates that radiosensitivity of human tumor cell lines can be evaluated in terms of growth delay, calculated cell survival, and spheroid control dose50 when grown as multicellular tumor spheroids. The sensitivity established from these evaluations parallels clinical behavior, thus offering a unique tool for the in vitro analysis of human tumor radiosensitivity

  7. Targeted SERS nanosensors measure physicochemical gradients and free energy changes in live 3D tumor spheroids.

    Science.gov (United States)

    Jamieson, Lauren E; Camus, Victoria L; Bagnaninchi, Pierre O; Fisher, Kate M; Stewart, Grant D; Nailon, William H; McLaren, Duncan B; Harrison, David J; Campbell, Colin J

    2016-09-22

    Use of multicellular tumor spheroids (MTS) to investigate therapies has gained impetus because they have potential to mimic factors including zonation, hypoxia and drug-resistance. However, analysis remains difficult and often destroys 3D integrity. Here we report an optical technique using targeted nanosensors that allows in situ 3D mapping of redox potential gradients whilst retaining MTS morphology and function. The magnitude of the redox potential gradient can be quantified as a free energy difference (ΔG) and used as a measurement of MTS viability. We found that by delivering different doses of radiotherapy to MTS we could correlate loss of ΔG with increasing therapeutic dose. In addition, we found that resistance to drug therapy was indicated by an increase in ΔG. This robust and reproducible technique allows interrogation of an in vitro tumor-model's bioenergetic response to therapy, indicating its potential as a tool for therapy development.

  8. Comparative Analysis of 3D Bladder Tumor Spheroids Obtained by Forced Floating and Hanging Drop Methods for Drug Screening

    OpenAIRE

    Amaral, Robson L. F.; Miranda, Mariza; Marcato, Priscyla D.; Swiech, Kamilla

    2017-01-01

    Introduction: Cell-based assays using three-dimensional (3D) cell cultures may reflect the antitumor activity of compounds more accurately, since these models reproduce the tumor microenvironment better. Methods: Here, we report a comparative analysis of cell behavior in the two most widely employed methods for 3D spheroid culture, forced floating (Ultra-low Attachment, ULA, plates), and hanging drop (HD) methods, using the RT4 human bladder cancer cell line as a model. The morphology para...

  9. Monitoring the Activation of the DNA Damage Response Pathway in a 3D Spheroid Model.

    Science.gov (United States)

    Mondesert, Odile; Frongia, Céline; Clayton, Olivia; Boizeau, Marie-Laure; Lobjois, Valérie; Ducommun, Bernard

    2015-01-01

    Monitoring the DNA-Damage Response (DDR) activated pathway in multicellular tumor spheroid models is an important challenge as these 3D models have demonstrated their major relevance in pharmacological evaluation. Herein we present DDR-Act-FP, a fluorescent biosensor that allows detection of DDR activation through monitoring of the p21 promoter p53-dependent activation. We show that cells expressing the DDR-Act-FP biosensor efficiently report activation of the DDR pathway after DNA damage and its pharmacological manipulation using ATM kinase inhibitors. We also report the successful use of this assay to screen a small compound library in order to identify activators of the DDR response. Finally, using multicellular spheroids expressing the DDR-Act-FP we demonstrate that DDR activation and its pharmacological manipulation with inhibitory and activatory compounds can be efficiently monitored in live 3D spheroid model. This study paves the way for the development of innovative screening and preclinical evaluation assays.

  10. Comparative Analysis of 3D Bladder Tumor Spheroids Obtained by Forced Floating and Hanging Drop Methods for Drug Screening

    Directory of Open Access Journals (Sweden)

    Robson L. F. Amaral

    2017-08-01

    Full Text Available Introduction: Cell-based assays using three-dimensional (3D cell cultures may reflect the antitumor activity of compounds more accurately, since these models reproduce the tumor microenvironment better.Methods: Here, we report a comparative analysis of cell behavior in the two most widely employed methods for 3D spheroid culture, forced floating (Ultra-low Attachment, ULA, plates, and hanging drop (HD methods, using the RT4 human bladder cancer cell line as a model. The morphology parameters and growth/metabolism of the spheroids generated were first characterized, using four different cell-seeding concentrations (0.5, 1.25, 2.5, and 3.75 × 104 cells/mL, and then, subjected to drug resistance evaluation.Results: Both methods generated spheroids with a smooth surface and round shape in a spheroidization time of about 48 h, regardless of the cell-seeding concentration used. Reduced cell growth and metabolism was observed in 3D cultures compared to two-dimensional (2D cultures. The optimal range of spheroid diameter (300–500 μm was obtained using cultures initiated with 0.5 and 1.25 × 104 cells/mL for the ULA method and 2.5 and 3.75 × 104 cells/mL for the HD method. RT4 cells cultured under 3D conditions also exhibited a higher resistance to doxorubicin (IC50 of 1.00 and 0.83 μg/mL for the ULA and HD methods, respectively compared to 2D cultures (IC50 ranging from 0.39 to 0.43.Conclusions: Comparing the results, we concluded that the forced floating method using ULA plates was considered more suitable and straightforward to generate RT4 spheroids for drug screening/cytotoxicity assays. The results presented here also contribute to the improvement in the standardization of the 3D cultures required for widespread application.

  11. A palladium label to monitor nanoparticle-assisted drug delivery of a photosensitizer into tumor spheroids by elemental bioimaging.

    Science.gov (United States)

    Niehoff, Ann-Christin; Moosmann, Aline; Söbbing, Judith; Wiehe, Arno; Mulac, Dennis; Wehe, Christoph A; Reifschneider, Olga; Blaske, Franziska; Wagner, Sylvia; Sperling, Michael; von Briesen, Hagen; Langer, Klaus; Karst, Uwe

    2014-01-01

    In this study, the cellular uptake of the second generation photosensitizer 5,10,15,20-tetrakis(3-hydroxyphenyl)porphyrin (mTHPP) was investigated using laser ablation coupled to inductively coupled plasma mass spectrometry (LA-ICP-MS) at a spatial resolution of 10 μm. To achieve high sensitivity, the photosensitizer was tagged with palladium. As a tumor model system, a 3D cell culture of the TKF-1 cell line was used. These tumor spheroids were incubated with the Pd-tagged photosensitizer embedded in poly(lactic-co-glycolic acid) (PLGA) nanoparticles to investigate the efficiency of nanoparticle based drug delivery. An accumulation of the drug in the first cell layers of the tumor spheroid was observed. In the case of nanoparticle based drug delivery, a significantly more homogeneous distribution of the photosensitizer was achieved, compared to tumor spheroids incubated with the dissolved photosensitizer without the nanoparticular drug delivery system. The infiltration depth of the Pd-tagged photosensitizer could not be increased with rising incubation time, which can be attributed to the adsorption of the photosensitizer onto cellular components.

  12. Generation of Multicellular Tumor Spheroids with Microwell-Based Agarose Scaffolds for Drug Testing.

    Directory of Open Access Journals (Sweden)

    Xue Gong

    Full Text Available Three dimensional multicellular aggregate, also referred to as cell spheroid or microtissue, is an indispensable tool for in vitro evaluating antitumor activity and drug efficacy. Compared with classical cellular monolayer, multicellular tumor spheroid (MCTS offers a more rational platform to predict in vivo drug efficacy and toxicity. Nevertheless, traditional processing methods such as plastic dish culture with nonadhesive surfaces are regularly time-consuming, laborious and difficult to provide uniform-sized spheroids, thus causing poor reproducibility of experimental data and impeding high-throughput drug screening. In order to provide a robust and effective platform for in vitro drug evaluation, we present an agarose scaffold prepared with the template containing uniform-sized micro-wells in commercially available cell culture plates. The agarose scaffold allows for good adjustment of MCTS size and large-scale production of MCTS. Transparent agarose scaffold also allows for monitoring of spheroid formation under an optical microscopy. The formation of MCTS from MCF-7 cells was prepared using different-size-well templates and systematically investigated in terms of spheroid growth curve, circularity, and cell viability. The doxorubicin cytotoxicity against MCF-7 spheroid and MCF-7 monolayer cells was compared. The drug penetration behavior, cell cycle distribution, cell apoptosis, and gene expression were also evaluated in MCF-7 spheroid. The findings of this study indicate that, compared with cellular monolayer, MCTS provides a valuable platform for the assessment of therapeutic candidates in an in vivo-mimic microenvironment, and thus has great potential for use in drug discovery and tumor biology research.

  13. A new, fast and semi-automated size determination method (SASDM) for studying multicellular tumor spheroids

    Science.gov (United States)

    Monazzam, Azita; Razifar, Pasha; Lindhe, Örjan; Josephsson, Raymond; Långström, Bengt; Bergström, Mats

    2005-01-01

    Background Considering the width and importance of using Multicellular Tumor Spheroids (MTS) in oncology research, size determination of MTSs by an accurate and fast method is essential. In the present study an effective, fast and semi-automated method, SASDM, was developed to determinate the size of MTSs. The method was applied and tested in MTSs of three different cell-lines. Frozen section autoradiography and Hemotoxylin Eosin (H&E) staining was used for further confirmation. Results SASDM was shown to be effective, user-friendly, and time efficient, and to be more precise than the traditional methods and it was applicable for MTSs of different cell-lines. Furthermore, the results of image analysis showed high correspondence to the results of autoradiography and staining. Conclusion The combination of assessment of metabolic condition and image analysis in MTSs provides a good model to evaluate the effect of various anti-cancer treatments. PMID:16283948

  14. 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.

  15. A model for sound absorption by spheroidal particles.

    Science.gov (United States)

    Hipp, Alexander K

    2009-06-01

    This paper describes a mathematical model for the scattering of acoustic waves in dispersions of prolate or oblate non-spherical particles. Based on fundamental equations of change for mass, momentum, and energy, wave equations are derived and solved in spheroidal coordinates. The examination of the boundary-value problem of an aligned spheroidal particle in a continuous medium, excited by a plane wave, leads to a description of the viscoinertial, thermal, and diffractive phenomena. The model is analogous to the Epstein-Carhart-Allegra-Hawley theory for spherical particles, and suggests itself for studying non-sphericity in the acoustic analysis of industrial dispersions.

  16. Micro-environmental mechanical stress controls tumor spheroid size and morphology by suppressing proliferation and inducing apoptosis in cancer cells.

    Directory of Open Access Journals (Sweden)

    Gang Cheng

    Full Text Available Compressive mechanical stress produced during growth in a confining matrix limits the size of tumor spheroids, but little is known about the dynamics of stress accumulation, how the stress affects cancer cell phenotype, or the molecular pathways involved.We co-embedded single cancer cells with fluorescent micro-beads in agarose gels and, using confocal microscopy, recorded the 3D distribution of micro-beads surrounding growing spheroids. The change in micro-bead density was then converted to strain in the gel, from which we estimated the spatial distribution of compressive stress around the spheroids. We found a strong correlation between the peri-spheroid solid stress distribution and spheroid shape, a result of the suppression of cell proliferation and induction of apoptotic cell death in regions of high mechanical stress. By compressing spheroids consisting of cancer cells overexpressing anti-apoptotic genes, we demonstrate that mechanical stress-induced apoptosis occurs via the mitochondrial pathway.Our results provide detailed, quantitative insight into the role of micro-environmental mechanical stress in tumor spheroid growth dynamics, and suggest how tumors grow in confined locations where the level of solid stress becomes high. An important implication is that apoptosis via the mitochondrial pathway, induced by compressive stress, may be involved in tumor dormancy, in which tumor growth is held in check by a balance of apoptosis and proliferation.

  17. 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.

  18. A Model for Spheroid versus Monolayer Response of SK-N-SH Neuroblastoma Cells to Treatment with 15-Deoxy-PGJ2

    Directory of Open Access Journals (Sweden)

    Dorothy I. Wallace

    2016-01-01

    Full Text Available Researchers have observed that response of tumor cells to treatment varies depending on whether the cells are grown in monolayer, as in vitro spheroids or in vivo. This study uses data from the literature on monolayer treatment of SK-N-SH neuroblastoma cells with 15-deoxy-PGJ2 and couples it with data on growth rates for untreated SK-N-SH neuroblastoma cells grown as multicellular spheroids. A linear model is constructed for untreated and treated monolayer data sets, which is tuned to growth, death, and cell cycle data for the monolayer case for both control and treatment with 15-deoxy-PGJ2. The monolayer model is extended to a five-dimensional nonlinear model of in vitro tumor spheroid growth and treatment that includes compartments of the cell cycle (G1,S,G2/M as well as quiescent (Q and necrotic (N cells. Monolayer treatment data for 15-deoxy-PGJ2 is used to derive a prediction of spheroid response under similar treatments. For short periods of treatment, spheroid response is less pronounced than monolayer response. The simulations suggest that the difference in response to treatment of monolayer versus spheroid cultures observed in laboratory studies is a natural consequence of tumor spheroid physiology rather than any special resistance to treatment.

  19. Mass transfer inside oblate spheroidal solids: modelling and simulation

    Directory of Open Access Journals (Sweden)

    J. E. F. Carmo

    2008-03-01

    Full Text Available A numerical solution of the unsteady diffusion equation describing mass transfer inside oblate spheroids, considering a constant diffusion coefficient and the convective boundary condition, is presented. The diffusion equation written in the oblate spheroidal coordinate system was used for a two-dimensional case. The finite-volume method was employed to discretize the basic equation. The linear equation set was solved iteratively using the Gauss-Seidel method. As applications, the effects of the Fourier number, the Biot number and the aspect ratio of the body on the drying rate and moisture content during the process are presented. To validate the methodology, results obtained in this work are compared with analytical results of the moisture content encountered in the literature and good agreement was obtained. The results show that the model is consistent and it may be used to solve cases such as those that include disks and spheres and/or those with variable properties with small modifications.

  20. Scattering center models of backscattering waves by dielectric spheroid objects.

    Science.gov (United States)

    Guo, Kun-Yi; Han, Xiao-Zhe; Sheng, Xin-Qing

    2018-02-19

    Scattering center models provide a simple and effective way of describing the complex electromagnetic scattering phenomena of targets and have been successfully applied in radar applications. However, the existing models are limited to conducting objects. Numerical results show that scattering centers of dielectric objects are far more complex than conducting objects and most of them are distributed beyond the object. For the lossless and low-loss media, the major scattering contributions to total fields are surface waves and multiple internal reflections rather than the direct reflection. Concise scattering center models for backscattering from dielectric spheroid objects are proposed in this work, which can characterize the backscattered waves by scattering centers with sparse and physical parameters. Good agreement has been demonstrated between the high resolution range profiles simulated by this model with those obtained by Mie series and the full wave numerical method.

  1. Cell proliferation kinetics and radiation response in 9L tumor spheroids

    Energy Technology Data Exchange (ETDEWEB)

    Sweigert, S.E.

    1984-05-01

    Cell kinetic parameters, including population doubling-time, cell cycle time, and growth fraction, were measured in 9L gliosarcoma spheroids. These parameters were studied as the spheroids grew from 50 ..mu..m to over 900 ..mu..m in diameter. Experiments relating the cell kinetic parameters to the radiation response of 9L spheroids were also carried out. The major findings were that the average cell cycle time (T/sub c/), is considerably longer in large spheroids than in exponentially-growing monolayers, the radiosensitivity of noncycling (but still viable) cells in spheroids is not significantly different from that of cycling spheroid cells, and the radiation-induced division delay is approximately twice as long in spheroid cells as in monolayer cells given equal radiation doses. The cell loss factor for spheroids of various sizes was calculated, by using the measured kinetic parameters in the basic equations for growth of a cell population. 157 references, 6 figures, 3 tables.

  2. Cell proliferation kinetics and radiation response in 9L tumor spheroids

    International Nuclear Information System (INIS)

    Sweigert, S.E.

    1984-05-01

    Cell kinetic parameters, including population doubling-time, cell cycle time, and growth fraction, were measured in 9L gliosarcoma spheroids. These parameters were studied as the spheroids grew from 50 μm to over 900 μm in diameter. Experiments relating the cell kinetic parameters to the radiation response of 9L spheroids were also carried out. The major findings were that the average cell cycle time (T/sub c/), is considerably longer in large spheroids than in exponentially-growing monolayers, the radiosensitivity of noncycling (but still viable) cells in spheroids is not significantly different from that of cycling spheroid cells, and the radiation-induced division delay is approximately twice as long in spheroid cells as in monolayer cells given equal radiation doses. The cell loss factor for spheroids of various sizes was calculated, by using the measured kinetic parameters in the basic equations for growth of a cell population. 157 references, 6 figures, 3 tables

  3. 3D high-content screening for the identification of compounds that target cells in dormant tumor spheroid regions

    Energy Technology Data Exchange (ETDEWEB)

    Wenzel, Carsten; Riefke, Björn; Gründemann, Stephan; Krebs, Alice; Christian, Sven; Prinz, Florian; Osterland, Marc; Golfier, Sven; Räse, Sebastian [Bayer Pharma AG, Global Drug Discovery, Muellerstrasse 178, 13353 Berlin (Germany); Ansari, Nariman [Physical Biology Group, Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University Frankfurt (Germany); Esner, Milan; Bickle, Marc [Max Planck Institute of Molecular Cell Biology and Genetics, High-Throughput Technology Development Studio (TDS), Dresden (Germany); Pampaloni, Francesco; Mattheyer, Christian; Stelzer, Ernst H. [Physical Biology Group, Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University Frankfurt (Germany); Parczyk, Karsten; Prechtl, Stefan [Bayer Pharma AG, Global Drug Discovery, Muellerstrasse 178, 13353 Berlin (Germany); Steigemann, Patrick, E-mail: Patrick.Steigemann@bayer.com [Bayer Pharma AG, Global Drug Discovery, Muellerstrasse 178, 13353 Berlin (Germany)

    2014-04-15

    Cancer cells in poorly vascularized tumor regions need to adapt to an unfavorable metabolic microenvironment. As distance from supplying blood vessels increases, oxygen and nutrient concentrations decrease and cancer cells react by stopping cell cycle progression and becoming dormant. As cytostatic drugs mainly target proliferating cells, cancer cell dormancy is considered as a major resistance mechanism to this class of anti-cancer drugs. Therefore, substances that target cancer cells in poorly vascularized tumor regions have the potential to enhance cytostatic-based chemotherapy of solid tumors. With three-dimensional growth conditions, multicellular tumor spheroids (MCTS) reproduce several parameters of the tumor microenvironment, including oxygen and nutrient gradients as well as the development of dormant tumor regions. We here report the setup of a 3D cell culture compatible high-content screening system and the identification of nine substances from two commercially available drug libraries that specifically target cells in inner MCTS core regions, while cells in outer MCTS regions or in 2D cell culture remain unaffected. We elucidated the mode of action of the identified compounds as inhibitors of the respiratory chain and show that induction of cell death in inner MCTS core regions critically depends on extracellular glucose concentrations. Finally, combinational treatment with cytostatics showed increased induction of cell death in MCTS. The data presented here shows for the first time a high-content based screening setup on 3D tumor spheroids for the identification of substances that specifically induce cell death in inner tumor spheroid core regions. This validates the approach to use 3D cell culture screening systems to identify substances that would not be detectable by 2D based screening in otherwise similar culture conditions. - Highlights: • Establishment of a novel method for 3D cell culture based high-content screening. • First reported high

  4. 3D high-content screening for the identification of compounds that target cells in dormant tumor spheroid regions

    International Nuclear Information System (INIS)

    Wenzel, Carsten; Riefke, Björn; Gründemann, Stephan; Krebs, Alice; Christian, Sven; Prinz, Florian; Osterland, Marc; Golfier, Sven; Räse, Sebastian; Ansari, Nariman; Esner, Milan; Bickle, Marc; Pampaloni, Francesco; Mattheyer, Christian; Stelzer, Ernst H.; Parczyk, Karsten; Prechtl, Stefan; Steigemann, Patrick

    2014-01-01

    Cancer cells in poorly vascularized tumor regions need to adapt to an unfavorable metabolic microenvironment. As distance from supplying blood vessels increases, oxygen and nutrient concentrations decrease and cancer cells react by stopping cell cycle progression and becoming dormant. As cytostatic drugs mainly target proliferating cells, cancer cell dormancy is considered as a major resistance mechanism to this class of anti-cancer drugs. Therefore, substances that target cancer cells in poorly vascularized tumor regions have the potential to enhance cytostatic-based chemotherapy of solid tumors. With three-dimensional growth conditions, multicellular tumor spheroids (MCTS) reproduce several parameters of the tumor microenvironment, including oxygen and nutrient gradients as well as the development of dormant tumor regions. We here report the setup of a 3D cell culture compatible high-content screening system and the identification of nine substances from two commercially available drug libraries that specifically target cells in inner MCTS core regions, while cells in outer MCTS regions or in 2D cell culture remain unaffected. We elucidated the mode of action of the identified compounds as inhibitors of the respiratory chain and show that induction of cell death in inner MCTS core regions critically depends on extracellular glucose concentrations. Finally, combinational treatment with cytostatics showed increased induction of cell death in MCTS. The data presented here shows for the first time a high-content based screening setup on 3D tumor spheroids for the identification of substances that specifically induce cell death in inner tumor spheroid core regions. This validates the approach to use 3D cell culture screening systems to identify substances that would not be detectable by 2D based screening in otherwise similar culture conditions. - Highlights: • Establishment of a novel method for 3D cell culture based high-content screening. • First reported high

  5. Spontaneous spheroid budding from monolayers: a potential contribution to ovarian cancer dissemination.

    Science.gov (United States)

    Pease, Jillian C; Brewer, Molly; Tirnauer, Jennifer S

    2012-07-15

    Ovarian cancer is the most lethal gynaecologic cancer, in large part because of its early dissemination and rapid development of chemotherapy resistance. Spheroids are clusters of tumor cells found in the peritoneal fluid of patients that are thought to promote this dissemination. Current models suggest that spheroids form by aggregation of single tumor cells shed from the primary tumor. Here, we demonstrate that spheroids can also form by budding directly as adherent clusters from a monolayer. Formation of budded spheroids correlated with expression of vimentin and lack of cortical E-cadherin. We also found that compared to cells grown in monolayers, cells grown as spheroids acquired progressive resistance to the chemotherapy drugs Paclitaxel and Cisplatin. This resistance could be completely reversed by dissociating the spheroids. Our observations highlight a previously unappreciated mode of spheroid formation that might have implications for tumor dissemination and chemotherapy resistance in patients, and suggest that this resistance might be reversed by spheroid dissociation.

  6. Short and long time effects of low temperature Plasma Activated Media on 3D multicellular tumor spheroids

    Science.gov (United States)

    Judée, Florian; Fongia, Céline; Ducommun, Bernard; Yousfi, Mohammed; Lobjois, Valérie; Merbahi, Nofel

    2016-02-01

    This work investigates the regionalized antiproliferative effects of plasma-activated medium (PAM) on colon adenocarcinoma multicellular tumor spheroid (MCTS), a model that mimics 3D organization and regionalization of a microtumor region. PAM was generated by dielectric barrier plasma jet setup crossed by helium carrier gas. MCTS were transferred in PAM at various times after plasma exposure up to 48 hours and effect on MCTS growth and DNA damage were evaluated. We report the impact of plasma exposure duration and delay before transfer on MCTS growth and DNA damage. Local accumulation of DNA damage revealed by histone H2AX phosphorylation is observed on outermost layers and is dependent on plasma exposure. DNA damage is completely reverted by catalase addition indicating that H2O2 plays major role in observed genotoxic effect while growth inhibitory effect is maintained suggesting that it is due to others reactive species. SOD and D-mannitol scavengers also reduced DNA damage by 30% indicating that and OH* are involved in H2O2 formation. Finally, PAM is able to retain its cytotoxic and genotoxic activity upon storage at +4 °C or -80 °C. These results suggest that plasma activated media may be a promising new antitumor strategy for colorectal cancer tumors.

  7. A Chemical Evolution Model for the Fornax Dwarf Spheroidal Galaxy

    Directory of Open Access Journals (Sweden)

    Yuan Zhen

    2016-01-01

    Full Text Available Fornax is the brightest Milky Way (MW dwarf spheroidal galaxy and its star formation history (SFH has been derived from observations. We estimate the time evolution of its gas mass and net inflow and outflow rates from the SFH usinga simple star formation law that relates the star formation rate to the gas mass. We present a chemical evolution model on a 2D mass grid with supernovae (SNe as sources of metal enrichment. We find that a key parameter controlling the enrichment is the mass Mx of the gas to mix with the ejecta from each SN. The choice of Mx depends on the evolution of SN remnants and on the global gas dynamics. It differs between the two types of SNe involved and between the periods before and after Fornax became an MW satellite at time t = tsat. Our results indicate that due to the global gas outflow at t > tsat, part of the ejecta from each SN may directly escape from Fornax. Sample results from our model are presented and compared with data.

  8. CONCENTRIC MACLAURIN SPHEROID MODELS OF ROTATING LIQUID PLANETS

    International Nuclear Information System (INIS)

    Hubbard, W. B.

    2013-01-01

    I present exact expressions for the interior gravitational potential V of a system of N concentric constant-density (Maclaurin) spheroids. I demonstrate an iteration procedure to find a self-consistent solution for the shapes of the interfaces between spheroids, and for the interior gravitational potential. The external free-space potential, expressed as a multipole expansion, emerges as part of the self-consistent solution. The procedure is both simpler and more precise than perturbation methods. One can choose the distribution and mass densities of the concentric spheroids so as to reproduce a prescribed barotrope to a specified accuracy. I demonstrate the method's efficacy by comparing its results with several published test cases.

  9. Rotenone exerts developmental neurotoxicity in a human brain spheroid model.

    Science.gov (United States)

    Pamies, David; Block, Katharina; Lau, Pierre; Gribaldo, Laura; Pardo, Carlos A; Barreras, Paula; Smirnova, Lena; Wiersma, Daphne; Zhao, Liang; Harris, Georgina; Hartung, Thomas; Hogberg, Helena T

    2018-02-08

    Growing concern suggests that some chemicals exert (developmental) neurotoxicity (DNT and NT) and are linked to the increase in incidence of autism, attention deficit and hyperactivity disorders. The high cost of routine tests for DNT and NT assessment make it difficult to test the high numbers of existing chemicals. Thus, more cost effective neurodevelopmental models are needed. The use of induced pluripotent stem cells (iPSC) in combination with the emerging human 3D tissue culture platforms, present a novel tool to predict and study human toxicity. By combining these technologies, we generated multicellular brain spheroids (BrainSpheres) from human iPSC. The model has previously shown to be reproducible and recapitulates several neurodevelopmental features. Our results indicate, rotenone's toxic potency varies depending on the differentiation status of the cells, showing higher reactive oxygen species (ROS) and higher mitochondrial dysfunction during early than later differentiation stages. Immuno-fluorescence morphology analysis after rotenone exposure indicated dopaminergic-neuron selective toxicity at non-cytotoxic concentrations (1 μM), while astrocytes and other neuronal cell types were affected at (general) cytotoxic concentrations (25 μM). Omics analysis showed changes in key pathways necessary for brain development, indicating rotenone as a developmental neurotoxicant and show a possible link between previously shown effects on neurite outgrowth and presently observed effects on Ca2+ reabsorption, synaptogenesis and PPAR pathway disruption. In conclusion, our BrainSpheres model has shown to be a reproducible and novel tool to study neurotoxicity and developmental neurotoxicity. Results presented here support the idea that rotenone can potentially be a developmental neurotoxicant. Copyright © 2018. Published by Elsevier Inc.

  10. A Novel Multiparametric Drug-Scoring Method for High-Throughput Screening of 3D Multicellular Tumor Spheroids Using the Celigo Image Cytometer.

    Science.gov (United States)

    Cribbes, Scott; Kessel, Sarah; McMenemy, Scott; Qiu, Jean; Chan, Leo Li-Ying

    2017-06-01

    Three-dimensional (3D) tumor models have been increasingly used to investigate and characterize cancer drug compounds. The ability to perform high-throughput screening of 3D multicellular tumor spheroids (MCTS) can highly improve the efficiency and cost-effectiveness of discovering potential cancer drug candidates. Previously, the Celigo Image Cytometer has demonstrated a novel method for high-throughput screening of 3D multicellular tumor spheroids. In this work, we employed the Celigo Image Cytometer to examine the effects of 14 cancer drug compounds on 3D MCTS of the glioblastoma cell line U87MG in 384-well plates. Using parameters such as MCTS diameter and invasion area, growth and invasion were monitored for 9 and 3 d, respectively. Furthermore, fluorescent staining with calcein AM, propidium iodide, Hoechst 33342, and caspase 3/7 was performed at day 9 posttreatment to measure viability and apoptosis. Using the kinetic and endpoint data generated, we created a novel multiparametric drug-scoring system for 3D MCTS that can be used to identify and classify potential drug candidates earlier in the drug discovery process. Furthermore, the combination of quantitative and qualitative image data can be used to delineate differences between drugs that induce cytotoxic and cytostatic effects. The 3D MCTS-based multiparametric scoring method described here can provide an alternative screening method to better qualify tested drug compounds.

  11. Advances in establishment and analysis of three-dimensional tumor spheroid-based functional assays for target validation and drug evaluation

    Directory of Open Access Journals (Sweden)

    Vinci Maria

    2012-03-01

    Full Text Available Abstract Background There is overwhelming evidence that in vitro three-dimensional tumor cell cultures more accurately reflect the complex in vivo microenvironment than simple two-dimensional cell monolayers, not least with respect to gene expression profiles, signaling pathway activity and drug sensitivity. However, most currently available three-dimensional techniques are time consuming and/or lack reproducibility; thus standardized and rapid protocols are urgently needed. Results To address this requirement, we have developed a versatile toolkit of reproducible three-dimensional tumor spheroid models for dynamic, automated, quantitative imaging and analysis that are compatible with routine high-throughput preclinical studies. Not only do these microplate methods measure three-dimensional tumor growth, but they have also been significantly enhanced to facilitate a range of functional assays exemplifying additional key hallmarks of cancer, namely cell motility and matrix invasion. Moreover, mutual tissue invasion and angiogenesis is accommodated by coculturing tumor spheroids with murine embryoid bodies within which angiogenic differentiation occurs. Highly malignant human tumor cells were selected to exemplify therapeutic effects of three specific molecularly-targeted agents: PI-103 (phosphatidylinositol-3-kinase (PI3K-mammalian target of rapamycin (mTOR inhibitor, 17-N-allylamino-17-demethoxygeldanamycin (17-AAG (heat shock protein 90 (HSP90 inhibitor and CCT130234 (in-house phospholipase C (PLCγ inhibitor. Fully automated analysis using a Celigo cytometer was validated for tumor spheroid growth and invasion against standard image analysis techniques, with excellent reproducibility and significantly increased throughput. In addition, we discovered key differential sensitivities to targeted agents between two-dimensional and three-dimensional cultures, and also demonstrated enhanced potency of some agents against cell migration

  12. Advances in establishment and analysis of three-dimensional tumor spheroid-based functional assays for target validation and drug evaluation

    Science.gov (United States)

    2012-01-01

    Background There is overwhelming evidence that in vitro three-dimensional tumor cell cultures more accurately reflect the complex in vivo microenvironment than simple two-dimensional cell monolayers, not least with respect to gene expression profiles, signaling pathway activity and drug sensitivity. However, most currently available three-dimensional techniques are time consuming and/or lack reproducibility; thus standardized and rapid protocols are urgently needed. Results To address this requirement, we have developed a versatile toolkit of reproducible three-dimensional tumor spheroid models for dynamic, automated, quantitative imaging and analysis that are compatible with routine high-throughput preclinical studies. Not only do these microplate methods measure three-dimensional tumor growth, but they have also been significantly enhanced to facilitate a range of functional assays exemplifying additional key hallmarks of cancer, namely cell motility and matrix invasion. Moreover, mutual tissue invasion and angiogenesis is accommodated by coculturing tumor spheroids with murine embryoid bodies within which angiogenic differentiation occurs. Highly malignant human tumor cells were selected to exemplify therapeutic effects of three specific molecularly-targeted agents: PI-103 (phosphatidylinositol-3-kinase (PI3K)-mammalian target of rapamycin (mTOR) inhibitor), 17-N-allylamino-17-demethoxygeldanamycin (17-AAG) (heat shock protein 90 (HSP90) inhibitor) and CCT130234 (in-house phospholipase C (PLC)γ inhibitor). Fully automated analysis using a Celigo cytometer was validated for tumor spheroid growth and invasion against standard image analysis techniques, with excellent reproducibility and significantly increased throughput. In addition, we discovered key differential sensitivities to targeted agents between two-dimensional and three-dimensional cultures, and also demonstrated enhanced potency of some agents against cell migration/invasion compared with

  13. Cell-free DNA in a three-dimensional spheroid cell culture model

    DEFF Research Database (Denmark)

    Aucamp, Janine; Calitz, Carlemi; Bronkhorst, Abel J.

    2017-01-01

    state, may be of significant benefit for cfDNA research. Methods CfDNA was isolated from the growth medium of C3A spheroid cultures in rotating bioreactors during both normal growth and treatment with acetaminophen. Spheroid growth was monitored via planimetry, lactate dehydrogenase activity and glucose...... environment. Combining 3D culture and cfDNA research could, therefore, optimize both research fields.......Background Investigating the biological functions of cell-free DNA (cfDNA) is limited by the interference of vast numbers of putative sources and causes of DNA release into circulation. Utilization of three-dimensional (3D) spheroid cell cultures, models with characteristics closer to the in vivo...

  14. A possible formation scenario for dwarf spheroidal galaxies - III. Adding star formation histories to the fiducial model

    Science.gov (United States)

    Alarcón Jara, A. G.; Fellhauer, M.; Matus Carrillo, D. R.; Assmann, P.; Urrutia Zapata, F.; Hazeldine, J.; Aravena, C. A.

    2018-02-01

    Dwarf spheroidal galaxies are regarded as the basic building blocks in the formation of larger galaxies and are the most dark matter dominated systems in the Universe, known so far. There are several models that attempt to explain their formation and evolution, but they have problems modelling the formation of isolated dwarf spheroidal galaxies. Here, we will explain a possible formation scenario in which star clusters form inside the dark matter halo of a dwarf spheroidal galaxy. These star clusters suffer from low star formation efficiency and dissolve while orbiting inside the dark matter halo. Thereby, they build the faint luminous components that we observe in dwarf spheroidal galaxies. In this paper, we study this model by adding different star formation histories to the simulations and compare the results with our previous work and observational data to show that we can explain the formation of dwarf spheroidal galaxies.

  15. Cardiac spheroids as promising in vitro models to study the human heart microenvironment

    DEFF Research Database (Denmark)

    Polonchuk, Liudmila; Chabria, Mamta; Badi, Laura

    2017-01-01

    Three-dimensional in vitro cell systems are a promising alternative to animals to study cardiac biology and disease. We have generated three-dimensional in vitro models of the human heart ("cardiac spheroids", CSs) by co-culturing human primary or iPSC-derived cardiomyocytes, endothelial cells an...

  16. A spheroid-based 3-D culture model for pancreatic cancer drug testing, using the acid phosphatase assay

    International Nuclear Information System (INIS)

    Wen, Z.; Liao, Q.; Hu, Y.; You, L.; Zhou, L.; Zhao, Y.

    2013-01-01

    Current therapy for pancreatic cancer is multimodal, involving surgery and chemotherapy. However, development of pancreatic cancer therapies requires a thorough evaluation of drug efficacy in vitro before animal testing and subsequent clinical trials. Compared to two-dimensional culture of cell monolayer, three-dimensional (3-D) models more closely mimic native tissues, since the tumor microenvironment established in 3-D models often plays a significant role in cancer progression and cellular responses to the drugs. Accumulating evidence has highlighted the benefits of 3-D in vitro models of various cancers. In the present study, we have developed a spheroid-based, 3-D culture of pancreatic cancer cell lines MIAPaCa-2 and PANC-1 for pancreatic drug testing, using the acid phosphatase assay. Drug efficacy testing showed that spheroids had much higher drug resistance than monolayers. This model, which is characteristically reproducible and easy and offers rapid handling, is the preferred choice for filling the gap between monolayer cell cultures and in vivo models in the process of drug development and testing for pancreatic cancer

  17. Modeling photopolarimetric characteristics of comet dust as a polydisperse mixture of polyshaped rough spheroids

    Science.gov (United States)

    Kolokolova, L.; Das, H.; Dubovik, O.; Lapyonok, T.

    2013-12-01

    It is widely recognized now that the main component of comet dust is aggregated particles that consist of submicron grains. It is also well known that cometary dust obey a rather wide size distribution with abundant particles whose size reaches dozens of microns. However, numerous attempts of computer simulation of light scattering by comet dust using aggregated particles have not succeeded to consider particles larger than a couple of microns due to limitations in the memory and speed of available computers. Attempts to substitute aggregates by polydisperse solid particles (spheres, spheroids, cylinders) could not consistently reproduce observed angular and spectral characteristics of comet brightness and polarization even in such a general case as polyshaped (i.e. containing particles of a variety of aspect ratios) mixture of spheroids (Kolokolova et al., In: Photopolarimetry in Remote Sensing, Kluwer Acad. Publ., 431, 2004). In this study we are checking how well cometary dust can be modeled using modeling tools for rough spheroids. With this purpose we use the software package described in Dubovik et al. (J. Geophys. Res., 111, D11208, doi:10.1029/2005JD006619d, 2006) that allows for a substantial reduction of computer time in calculating scattering properties of spheroid mixtures by means of using pre-calculated kernels - quadrature coefficients employed in the numerical integration of spheroid optical properties over size and shape. The kernels were pre-calculated for spheroids of 25 axis ratios, ranging from 0.3 to 3, and 42 size bins within the size parameter range 0.01 - 625. This software package has been recently expanded with the possibility of simulating not only smooth but also rough spheroids that is used in present study. We consider refractive indexes of the materials typical for comet dust: silicate, carbon, organics, and their mixtures. We also consider porous particles accounting on voids in the spheroids through effective medium approach. The

  18. Spheroid model study comparing the biocompatibility of Biodentine and MTA.

    Science.gov (United States)

    Pérard, Matthieu; Le Clerc, Justine; Watrin, Tanguy; Meary, Fleur; Pérez, Fabienne; Tricot-Doleux, Sylvie; Pellen-Mussi, Pascal

    2013-06-01

    The primary objective of this study was to assess the biological effects of a new dentine substitute based on Ca₃SiO₅ (Biodentine™) for use in pulp-capping treatment, on pseudo-odontoblastic (MDPC-23) and pulp (Od-21) cells. The secondary objective was to evaluate the effects of Biodentine and mineral trioxide aggregate (MTA) on gene expression in cultured spheroids. We used the acid phosphatase assay to compare the biocompatibility of Biodentine and MTA. Cell differentiation was investigated by RT-qPCR. We investigated the expression of genes involved in odontogenic differentiation (Runx2), matrix secretion (Col1a1, Spp1) and mineralisation (Alp). ANOVA and PLSD tests were used for data analysis. MDPC-23 cells cultured in the presence of MTA had higher levels of viability than those cultured in the presence of Biodentine and control cells on day 7 (P = 0.0065 and P = 0.0126, respectively). For Od-21 cells, proliferation rates on day 7 were significantly lower in the presence of Biodentine or MTA than for control (P Biodentine and in control cells. Biodentine and MTA may modify the proliferation of pulp cell lines. Their effects may fluctuate over time, depending on the cell line considered. The observed similarity between Biodentine and MTA validates the indication for direct pulp-capping claimed by the manufacturers.

  19. Down-regulation of DNA mismatch repair proteins in human and murine tumor spheroids: implications for multicellular resistance to alkylating agents.

    Science.gov (United States)

    Francia, Giulio; Green, Shane K; Bocci, Guido; Man, Shan; Emmenegger, Urban; Ebos, John M L; Weinerman, Adina; Shaked, Yuval; Kerbel, Robert S

    2005-10-01

    Similar to other anticancer agents, intrinsic or acquired resistance to DNA-damaging chemotherapeutics is a major obstacle for cancer therapy. Current strategies aimed at overcoming this problem are mostly based on the premise that tumor cells acquire heritable genetic mutations that contribute to drug resistance. Here, we present evidence for an epigenetic, tumor cell adhesion-mediated, and reversible form of drug resistance that is associated with a reduction of DNA mismatch repair proteins PMS2 and/or MLH1 as well as other members of this DNA repair process. Growth of human breast cancer, human melanoma, and murine EMT-6 breast cancer cell lines as multicellular spheroids in vitro, which is associated with increased resistance to many chemotherapeutic drugs, including alkylating agents, is shown to lead to a reproducible down-regulation of PMS2, MLH1, or, in some cases, both as well as MHS6, MSH3, and MSH2. The observed down-regulation is in part reversible by treatment of tumor spheroids with the DNA-demethylating agent, 5-azacytidine. Thus, treatment of EMT-6 mouse mammary carcinoma spheroids with 5-azacytidine resulted in reduced and/or disrupted cell-cell adhesion, which in turn sensitized tumor spheroids to cisplatin-mediated killing in vitro. Our results suggest that antiadhesive agents might sensitize tumor spheroids to alkylating agents in part by reversing or preventing reduced DNA mismatch repair activity and that the chemosensitization properties of 5-azacytidine may conceivably reflect its role as a potential antiadhesive agent as well as reversal agent for MLH1 gene silencing in human tumors.

  20. Model-independent constraints on dark matter annihilation in dwarf spheroidal galaxies

    OpenAIRE

    Boddy, Kimberly; Kumar, Jason; Marfatia, Danny; Sandick, Pearl

    2018-01-01

    We present a general, model-independent formalism for determining bounds on the production of photons in dwarf spheroidal galaxies via dark matter annihilation, applicable to any set of assumptions about dark matter particle physics or astrophysics. As an illustration, we analyze gamma-ray data from the Fermi Large Area Telescope to constrain a variety of nonstandard dark matter models, several of which have not previously been studied in the context of dwarf galaxy searches.

  1. Tumor stroma-containing 3D spheroid arrays: A tool to study nanoparticle penetration

    NARCIS (Netherlands)

    Priwitaningrum, Dwi L.; Priwitaningrum, Dwi Lestari; Blondé, Jean-Baptiste Gabriel Marie; Blonde, Jean-Baptiste G.; Sridhar, Adithya; van Baarlen, Joop; Hennink, Wim E.; Storm, Gerrit; le Gac, Severine; Prakash, Jai

    2016-01-01

    Nanoparticle penetration through tumor tissue after extravasation is considered as a key issue for tumor distribution and therapeutic effects. Most tumors possess abundant stroma, a fibrotic tissue composed of cancer-associated fibroblasts (CAFs) and extracellular matrix (ECM), which acts as a

  2. Modelling kidney disease with CRISPR-mutant kidney organoids derived from human pluripotent epiblast spheroids

    Science.gov (United States)

    Freedman, Benjamin S.; Brooks, Craig R.; Lam, Albert Q.; Fu, Hongxia; Morizane, Ryuji; Agrawal, Vishesh; Saad, Abdelaziz F.; Li, Michelle K.; Hughes, Michael R.; Werff, Ryan Vander; Peters, Derek T.; Lu, Junjie; Baccei, Anna; Siedlecki, Andrew M.; Valerius, M. Todd; Musunuru, Kiran; McNagny, Kelly M.; Steinman, Theodore I.; Zhou, Jing; Lerou, Paul H.; Bonventre, Joseph V.

    2015-01-01

    Human-pluripotent-stem-cell-derived kidney cells (hPSC-KCs) have important potential for disease modelling and regeneration. Whether the hPSC-KCs can reconstitute tissue-specific phenotypes is currently unknown. Here we show that hPSC-KCs self-organize into kidney organoids that functionally recapitulate tissue-specific epithelial physiology, including disease phenotypes after genome editing. In three-dimensional cultures, epiblast-stage hPSCs form spheroids surrounding hollow, amniotic-like cavities. GSK3β inhibition differentiates spheroids into segmented, nephron-like kidney organoids containing cell populations with characteristics of proximal tubules, podocytes and endothelium. Tubules accumulate dextran and methotrexate transport cargoes, and express kidney injury molecule-1 after nephrotoxic chemical injury. CRISPR/Cas9 knockout of podocalyxin causes junctional organization defects in podocyte-like cells. Knockout of the polycystic kidney disease genes PKD1 or PKD2 induces cyst formation from kidney tubules. All of these functional phenotypes are distinct from effects in epiblast spheroids, indicating that they are tissue specific. Our findings establish a reproducible, versatile three-dimensional framework for human epithelial disease modelling and regenerative medicine applications. PMID:26493500

  3. Energy metabolism and biotransformation as endpoints to pre-screen hepatotoxicity using a liver spheroid model

    International Nuclear Information System (INIS)

    Xu Jinsheng; Purcell, Wendy M.

    2006-01-01

    The current study investigated liver spheroid culture as an in vitro model to evaluate the endpoints relevant to the status of energy metabolism and biotransformation after exposure to test toxicants. Mature rat liver spheroids were exposed to diclofenac, galactosamine, isoniazid, paracetamol, m-dinitrobenzene (m-DNB) and 3-nitroaniline (3-NA) for 24 h. Pyruvate uptake, galactose biotransformation, lactate release and glucose secretion were evaluated after exposure. The results showed that pyruvate uptake and lactate release by mature liver spheroids in culture were maintained at a relatively stable level. These endpoints, together with glucose secretion and galactose biotransformation, were related to and could reflect the status of energy metabolism and biotransformation in hepatocytes. After exposure, all of the test agents significantly reduced glucose secretion, which was shown to be the most sensitive endpoint of those evaluated. Diclofenac, isoniazid, paracetamol and galactosamine reduced lactate release (P < 0.01), but m-DNB increased lactate release (P < 0.01). Diclofenac, isoniazid and paracetamol also reduced pyruvate uptake (P < 0.01), while galactosamine had little discernible effect. Diclofenac, galactosamine, paracetamol and m-DNB also reduced galactose biotransformation (P < 0.01), by contrast, isoniazid did not. The metabolite of m-DNB, 3-NA, which served as a negative control, did not cause significant changes in lactate release, pyruvate uptake or galactose biotransformation. It is concluded that pyruvate uptake, galactose biotransformation, lactate release and glucose secretion can be used as endpoints for evaluating the status of energy metabolism and biotransformation after exposure to test agents using the liver spheroid model to pre-screen hepatotoxicity

  4. Spherical Cancer Models in Tumor Biology

    Directory of Open Access Journals (Sweden)

    Louis-Bastien Weiswald

    2015-01-01

    Full Text Available Three-dimensional (3D in vitro models have been used in cancer research as an intermediate model between in vitro cancer cell line cultures and in vivo tumor. Spherical cancer models represent major 3D in vitro models that have been described over the past 4 decades. These models have gained popularity in cancer stem cell research using tumorospheres. Thus, it is crucial to define and clarify the different spherical cancer models thus far described. Here, we focus on in vitro multicellular spheres used in cancer research. All these spherelike structures are characterized by their well-rounded shape, the presence of cancer cells, and their capacity to be maintained as free-floating cultures. We propose a rational classification of the four most commonly used spherical cancer models in cancer research based on culture methods for obtaining them and on subsequent differences in sphere biology: the multicellular tumor spheroid model, first described in the early 70s and obtained by culture of cancer cell lines under nonadherent conditions; tumorospheres, a model of cancer stem cell expansion established in a serum-free medium supplemented with growth factors; tissue-derived tumor spheres and organotypic multicellular spheroids, obtained by tumor tissue mechanical dissociation and cutting. In addition, we describe their applications to and interest in cancer research; in particular, we describe their contribution to chemoresistance, radioresistance, tumorigenicity, and invasion and migration studies. Although these models share a common 3D conformation, each displays its own intrinsic properties. Therefore, the most relevant spherical cancer model must be carefully selected, as a function of the study aim and cancer type.

  5. Spherical cancer models in tumor biology.

    Science.gov (United States)

    Weiswald, Louis-Bastien; Bellet, Dominique; Dangles-Marie, Virginie

    2015-01-01

    Three-dimensional (3D) in vitro models have been used in cancer research as an intermediate model between in vitro cancer cell line cultures and in vivo tumor. Spherical cancer models represent major 3D in vitro models that have been described over the past 4 decades. These models have gained popularity in cancer stem cell research using tumorospheres. Thus, it is crucial to define and clarify the different spherical cancer models thus far described. Here, we focus on in vitro multicellular spheres used in cancer research. All these spherelike structures are characterized by their well-rounded shape, the presence of cancer cells, and their capacity to be maintained as free-floating cultures. We propose a rational classification of the four most commonly used spherical cancer models in cancer research based on culture methods for obtaining them and on subsequent differences in sphere biology: the multicellular tumor spheroid model, first described in the early 70s and obtained by culture of cancer cell lines under nonadherent conditions; tumorospheres, a model of cancer stem cell expansion established in a serum-free medium supplemented with growth factors; tissue-derived tumor spheres and organotypic multicellular spheroids, obtained by tumor tissue mechanical dissociation and cutting. In addition, we describe their applications to and interest in cancer research; in particular, we describe their contribution to chemoresistance, radioresistance, tumorigenicity, and invasion and migration studies. Although these models share a common 3D conformation, each displays its own intrinsic properties. Therefore, the most relevant spherical cancer model must be carefully selected, as a function of the study aim and cancer type. Copyright © 2014 Neoplasia Press, Inc. Published by Elsevier Inc. All rights reserved.

  6. Response of the MG-63 human osteosarcoma cell line grown as multicellular spheroids to neutron irradiation

    International Nuclear Information System (INIS)

    Kubota, Nobuo; Kakehi, Masae; Matsubara, Shou; Koike, Sachiko; Ando, Koichi.

    1993-01-01

    Multicellular tumor spheroids are composed of the mixed populations of cells with regard to cell proliferation, nutrition, oxygenation and radiosensitivity. Human osteogenic sarcoma is generally considered clinically radioresistant. However, the in vitro cell survival curves for human osteogenic sarcoma cell lines do not differ from those of other tumor cell lines. In this study, the responses of human osteogenic sarcoma cell line to gamma ray and neutrons were investigated by using spheroid system. The spheroids of the osteogenic sarcoma cell line are considered to be a good in vitro model of radioresistant tumors. The purpose of this study is to measure the response of the spheroids to fast neutron irradiation. MG-63 human osteogenic sarcoma cell line was used for this study. The cell line was cultured in alpha-MEM with supplement. Cell survival was estimated after the trypsinization of spheroids 24 hours after irradiation. The method of measuring spheroid cure is explained. The mean number of surviving cells per spheroid can be obtained from the mean clonogenic number and cell survival curve. The cell survival of MG-63 spheroids exposed to gamma ray and neutrons and the dose effect curves for spheroid cure after irradiation are shown. (K.I.)

  7. Short-term spheroid culture of primary colorectal cancer cells as an in vitro model for personalizing cancer medicine

    DEFF Research Database (Denmark)

    Jeppesen, Maria; Hagel, Grith; Glenthoj, Anders

    2017-01-01

    Chemotherapy treatment of cancer remains a challenge due to the molecular and functional heterogeneity displayed by tumours originating from the same cell type. The pronounced heterogeneity makes it difficult for oncologists to devise an effective therapeutic strategy for the patient. One approach...... for increasing treatment efficacy is to test the chemosensitivity of cancer cells obtained from the patient's tumour. 3D culture represents a promising method for modelling patient tumours in vitro. The aim of this study was therefore to evaluate how closely short-term spheroid cultures of primary colorectal...... cancer cells resemble the original tumour. Colorectal cancer cells were isolated from human tumour tissue and cultured as spheroids. Spheroid cultures were established with a high success rate and remained viable for at least 10 days. The spheroids exhibited significant growth over a period of 7 days...

  8. Vascularization of human glioma spheroids implanted into rat cortex is conferred by two distinct mechanisms.

    Science.gov (United States)

    Goldbrunner, R H; Bernstein, J J; Plate, K H; Vince, G H; Roosen, K; Tonn, J C

    1999-02-15

    Aim of this study was to develop and characterize an applicable in vivo model to investigate angiogenesis of human gliomas. An established glioblastoma spheroid model was used to investigate the neovascularization of a standardized avascular solid tumor mass. Spheroids of two human glioma cell lines were labeled with an in vivo fluorescent dye. Single spheroids were implanted into the cortex of athymic rats. After 1, 3, 7, 14, and 21 days, brain sections containing the spheroid were immunostained for endothelial cells or vascular endothelial growth factor (VEGF). The dye-stained glioma spheroid and the endothelial cells were visualized by confocal microscopy. Two distinct mechanisms of tumor vascularization could be observed. (1) "Classical" angiogenesis with new vessels sprouting from existing host vessels into the spheroid was seen. (2) Individual endothelial cells were found to migrate towards and into the center of the spheroid where they coalesced to form new vessels. This process occurred as early as 24 hr after spheroid implantation. Spheroid vascularization was accompanied by an increase of VEGF expression, which peaked 7 days after implantation and returned to normal patterns by 14-21 days. Besides the "classical" angiogenesis by angiogenic blood vessels, the recruitment of individual endothelial cells seems to be an additional mechanism in early glioma vascularization. Our model proves to be a reliable, reproducible system to study in vivo angiogenesis of human gliomas. Copyright 1999 Wiley-Liss, Inc.

  9. Spatial distribution of elements in the spheroids by prostate tumor cells using synchrotron radiation X-ray fluorescence

    International Nuclear Information System (INIS)

    Leitao, Roberta G.; Canellas, Catarine G.L.; Anjos, Marcelino J.; Lopes, Ricardo T.; Santos, Carlos Antonio N.; Palumbo Junior, Antonio; Souza, Pedro A.V.R.; Nasciutti, Luiz E.

    2011-01-01

    The formation of three-dimensional cell microspheres such as spheroids has attracted attention as a useful culture technique. In this study, we investigated the trace elemental distribution (mapping) in spheroids derived from tissue prostate cancer (PCa). The measurements were performed in standard geometry of 45 deg incidence, exciting with a white beam and using an optical capillary with 20 μm diameter collimation in the XRF beam line at the Synchrotron Light National Laboratory (Campinas, Brazil). The results showed that most elements analyzed presented non-uniform distribution. P, S and Cl showed similar elemental distribution in all the samples analyzed. K, Ca, Fe, and Cu showed different elemental distribution for the spheroids analyzed. Zinc presented more intense distributions in the spheroid central region for all spheroids analyzed. (author)

  10. Spatial distribution of elements in the spheroids by prostate tumor cells using synchrotron radiation X-ray fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Leitao, Roberta G.; Canellas, Catarine G.L.; Anjos, Marcelino J.; Lopes, Ricardo T. [Universidade Federal do Rio de Janeiro (PEN/COPPE/UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-Graduacao de Engenharia. Programa de Energia Nuclear; Santos, Carlos Antonio N. [Instituto Nacional de Metrologia, Normalizacao e Qualidade Industrial (INMETRO), Duque de Caxias, RJ (Brazil). Lab. de Biotecnologia - Bioengenharia; Palumbo Junior, Antonio; Souza, Pedro A.V.R.; Nasciutti, Luiz E., E-mail: nasciutt@ufrj.b [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Lab. de Interacoes Celulares

    2011-07-01

    The formation of three-dimensional cell microspheres such as spheroids has attracted attention as a useful culture technique. In this study, we investigated the trace elemental distribution (mapping) in spheroids derived from tissue prostate cancer (PCa). The measurements were performed in standard geometry of 45 deg incidence, exciting with a white beam and using an optical capillary with 20 {mu}m diameter collimation in the XRF beam line at the Synchrotron Light National Laboratory (Campinas, Brazil). The results showed that most elements analyzed presented non-uniform distribution. P, S and Cl showed similar elemental distribution in all the samples analyzed. K, Ca, Fe, and Cu showed different elemental distribution for the spheroids analyzed. Zinc presented more intense distributions in the spheroid central region for all spheroids analyzed. (author)

  11. Spatial distribution of elements in the spheroids by prostate tumor cells using synchrotron radiation x-ray fluorescence

    International Nuclear Information System (INIS)

    Leitao, Roberta G.; Santos, Carlos Antonio N.; Junior, Antonio Palumbo; Souza, Pedro A. V. R.; Canellas, Catarine G. L.; Anjos, Marcelino J.; Nasciutti, Luiz E.; Lopes, Ricardo T.

    2012-01-01

    The formation of three-dimensional cell microspheres such as spheroids has attracted attention as a useful culture technique. In this study, we investigated the trace elemental distribution (mapping) in spheroids derived from tissue prostate cancer (PCa). The measurements were performed in standard geometry of 45 deg. incidence, exciting with a white beam and using an optical capillary with 20 μm diameter collimation in the XRF beam line at the Synchrotron Light National Laboratory (Campinas, Brazil). The results showed that most elements analyzed presented non-uniform distribution. P, S and Cl showed similar elemental distribution in all the samples analyzed. K, Ca, Fe, and Cu showed different elemental distribution for the spheroids analyzed. Zinc presented more intense distributions in the spheroid central region for all spheroids analyzed.

  12. Effects of combinations of chemotherapy and radiation on the emergence of drug resistant cells in 9L rat brain tumor spheroids

    International Nuclear Information System (INIS)

    Tofilon, P.J.; Arundel, C.; Vines, C.M.

    1987-01-01

    Repeated administration of antineoplastic chemotherapeutic agents is generally considered to induce and/or select for drug resistant cells. The authors recently begun to investigate whether chemotherapy interdigitated with radiation can minimize or eliminate the emergence of drug resiistent cells in 9L rat brain tumor spheroids grown from defined mixtures of cells sensitive (9L) and resistant (R/sub 3/) to BCNU. In this experimental system, the sister chromatid exchange (SCE) assay is used to quantitate the proportions of sensitive and resistant cells within the spheroids. While 9L and R/sub 3/ cell have different sensitivities to BCNU, they are equally sensitive to radiation. Mixed-cell spheroids consisting of 1% R/sub 3/ cells were treated with three doses of BCNU (10 μM) every 72 hr resulting in a shift in the 9L to R/sub 3/ ratio to greater than 50% R/sub 3/ cells. The combined protocols to be investigated will involve γ rays administered either 36 hr before or after each BCNU treatment. By initiating these combined protocols on spheroids of different sizes, the effectiveness of each protocol is evaluated with respect to the number of resistant cells present

  13. INSIDIA: A FIJI Macro Delivering High-Throughput and High-Content Spheroid Invasion Analysis.

    Science.gov (United States)

    Moriconi, Chiara; Palmieri, Valentina; Di Santo, Riccardo; Tornillo, Giusy; Papi, Massimiliano; Pilkington, Geoff; De Spirito, Marco; Gumbleton, Mark

    2017-10-01

    Time-series image capture of in vitro 3D spheroidal cancer models embedded within an extracellular matrix affords examination of spheroid growth and cancer cell invasion. However, a customizable, comprehensive and open source solution for the quantitative analysis of such spheroid images is lacking. Here, the authors describe INSIDIA (INvasion SpheroID ImageJ Analysis), an open-source macro implemented as a customizable software algorithm running on the FIJI platform, that enables high-throughput high-content quantitative analysis of spheroid images (both bright-field gray and fluorescent images) with the output of a range of parameters defining the spheroid "tumor" core and its invasive characteristics. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Establishment and Characterization of a Tumor Stem Cell-Based Glioblastoma Invasion Model.

    Directory of Open Access Journals (Sweden)

    Stine Skov Jensen

    Full Text Available Glioblastoma is the most frequent and malignant brain tumor. Recurrence is inevitable and most likely connected to tumor invasion and presence of therapy resistant stem-like tumor cells. The aim was therefore to establish and characterize a three-dimensional in vivo-like in vitro model taking invasion and tumor stemness into account.Glioblastoma stem cell-like containing spheroid (GSS cultures derived from three different patients were established and characterized. The spheroids were implanted in vitro into rat brain slice cultures grown in stem cell medium and in vivo into brains of immuno-compromised mice. Invasion was followed in the slice cultures by confocal time-lapse microscopy. Using immunohistochemistry, we compared tumor cell invasion as well as expression of proliferation and stem cell markers between the models.We observed a pronounced invasion into brain slice cultures both by confocal time-lapse microscopy and immunohistochemistry. This invasion closely resembled the invasion in vivo. The Ki-67 proliferation indexes in spheroids implanted into brain slices were lower than in free-floating spheroids. The expression of stem cell markers varied between free-floating spheroids, spheroids implanted into brain slices and tumors in vivo.The established invasion model kept in stem cell medium closely mimics tumor cell invasion into the brain in vivo preserving also to some extent the expression of stem cell markers. The model is feasible and robust and we suggest the model as an in vivo-like model with a great potential in glioma studies and drug discovery.

  15. Towards personalized computational oncology: from spatial models of tumour spheroids, to organoids, to tissues.

    Science.gov (United States)

    Karolak, Aleksandra; Markov, Dmitry A; McCawley, Lisa J; Rejniak, Katarzyna A

    2018-01-01

    A main goal of mathematical and computational oncology is to develop quantitative tools to determine the most effective therapies for each individual patient. This involves predicting the right drug to be administered at the right time and at the right dose. Such an approach is known as precision medicine. Mathematical modelling can play an invaluable role in the development of such therapeutic strategies, since it allows for relatively fast, efficient and inexpensive simulations of a large number of treatment schedules in order to find the most effective. This review is a survey of mathematical models that explicitly take into account the spatial architecture of three-dimensional tumours and address tumour development, progression and response to treatments. In particular, we discuss models of epithelial acini, multicellular spheroids, normal and tumour spheroids and organoids, and multi-component tissues. Our intent is to showcase how these in silico models can be applied to patient-specific data to assess which therapeutic strategies will be the most efficient. We also present the concept of virtual clinical trials that integrate standard-of-care patient data, medical imaging, organ-on-chip experiments and computational models to determine personalized medical treatment strategies. © 2018 The Author(s).

  16. Encapsulation by Janus spheroids

    OpenAIRE

    Li, Wei; Liu, Ya; Brett, Genevieve; Gunton, James D.

    2011-01-01

    The micro/nano encapsulation technology has acquired considerable attention in the fields of drug delivery, biomaterial engineering, and materials science. Based on recent advances in chemical particle synthesis, we propose a primitive model of an encapsulation system produced by the self-assembly of Janus oblate spheroids, particles with oblate spheroidal bodies and two hemi-surfaces coded with dissimilar chemical properties. Using Monte Carlo simulation, we investigate the encapsulation sys...

  17. Visualization of Surface Flow on a Prolate Spheroid Model Suspended by Magnetic Suspension and Balance System

    Science.gov (United States)

    Ambo, Takumi; Nakamura, Yuki; Ochiai, Taku; Nonomura, Taku; Asai, Keisuke

    2017-11-01

    In this study, the surface flow on a 6:1 prolate spheroid model was visualized by oil flow method in the magnetic suspension and balance system (MSBS). The MSBS is a support-free system for wind-tunnel test in that a model is levitated by magnetic force. In this experiment, the 0.3-m MSBS was installed in the low-speed wind tunnel. The Reynolds number was 0.5 million and the angle of attack was set 0 and 5 degrees. In addition to free-levitation tests, a thin rod simulating disturbance of a support system was placed on the model surface and the influence of support interference was evaluated. The obtained results indicate that complicated separation patterns are present even at zero angle of attack. At α = 5°, separation pattern becomes more complicated than that at α = 0° and the streamlines form a highly three-dimensional structure. A characteristic pattern of open separation is observed and a focal point is formed at the end of the separation line. In evaluation of the support interference, the separation is delayed in the downstream of the rod, suggesting that the change of separation pattern is caused by the transition of laminar boundary layer behind the rod. These results indicate that one must take particular care to the support interference in studying three-dimensional separation on a prolate spheroid.

  18. Human adipose-derived stem cell spheroid treated with photobiomodulation irradiation accelerates tissue regeneration in mouse model of skin flap ischemia.

    Science.gov (United States)

    Park, In-Su; Chung, Phil-Sang; Ahn, Jin Chul; Leproux, Anais

    2017-11-01

    Skin flap grafting is a form of transplantation widely used in plastic surgery. However, ischemia/reperfusion injury is the main factor which reduces the survival rate of flaps following grafting. We investigated whether photobiomodulation (PBM) precondition prior to human adipose-derived stromal cell (hASC) spheroid (PBM-spheroid) transplantation improved skin tissue functional recovery by the stimulation of angiogenesis and tissue regeneration in skin flap of mice. The LED had an emission wavelength peaked at 660 ± 20 nm (6 J/cm 2 , 10 mW/cm 2 ). The expression of angiogenic growth factors in PBM-spheroid hASCs was much greater than that of not-PBM-treated spheroid or monolayer-cultured hASCs. From immunochemical staining analysis, the hASCs of PBM-spheroid were CD31 + , KDR + , and CD34 + , whereas monolayer-cultured hASCs were negative for these markers. To evaluate the therapeutic effect of hASC PBM-spheroid in vivo, PBS, monolayer-cultured hASCs, and not-PBM-spheroid were transplanted into a skin flap model. The animals were observed for 14 days. The PBM-spheroid hASCs transplanted into the skin flap ischemia differentiated into endothelial cells and remained differentiated. Transplantation of PBM-spheroid hASCs into the skin flap ischemia significantly elevated the density of vascular formations through angiogenic factors released by the skin flap ischemia and enhanced tissue regeneration at the lesion site. Consistent with these results, the transplantation of PBM-spheroid hASCs significantly improved functional recovery compared with PBS, monolayer-cultured hASCs, and not-PBM-spheroid treatment. These findings suggest that transplantation of PBM-spheroid hASCs may be an effective stem cell therapy for the treatment of skin flap ischemia.

  19. Shape dependency of the extinction and absorption cross sections of dust aerosols modeled as randomly oriented spheroids

    Directory of Open Access Journals (Sweden)

    R. Wagner

    2011-09-01

    Full Text Available We present computational results on the shape dependency of the extinction and absorption cross sections of dustlike aerosol particles that were modeled as randomly oriented spheroids. Shape dependent variations in the extinction cross sections are largest in the size regime that is governed by the interference structure. Elongated spheroids best fitted measured extinction spectra of re-dispersed Saharan dust samples. For dust particles smaller than 1.5 μm in diameter and low absorption potential, shape effects on the absorption cross sections are very small.

  20. Spectroscopic imaging system for high-throughput viability assessment of ovarian spheroids or microdissected tumor tissues (MDTs) in a microfluidic chip

    Science.gov (United States)

    St-Georges-Robillard, A.; Masse, M.; Kendall-Dupont, J.; Strupler, M.; Patra, B.; Jermyn, M.; Mes-Masson, A.-M.; Leblond, F.; Gervais, T.

    2016-02-01

    There is a growing effort in the biomicrosystems community to develop a personalized treatment response assay for cancer patients using primary cells, patient-derived spheroids, or live tissues on-chip. Recently, our group has developed a technique to cut tumors in 350 μm diameter microtissues and keep them alive on-chip, enabling multiplexed in vitro drug assays on primary tumor tissue. Two-photon microscopy, confocal microscopy and flow cytometry are the current standard to assay tissue chemosensitivity on-chip. While these techniques provide microscopic and molecular information, they are not adapted for high-throughput analysis of microtissues. We present a spectroscopic imaging system that allows rapid quantitative measurements of multiple fluorescent viability markers simultaneously by using a liquid crystal tunable filter to record fluorescence and transmittance spectra. As a proof of concept, 24 spheroids composed of ovarian cancer cell line OV90 were formed in a microfluidic chip, stained with two live cell markers (CellTrackerTM Green and Orange), and imaged. Fluorescence images acquired were normalized to the acquisition time and gain of the camera, dark noise was removed, spectral calibration was applied, and spatial uniformity was corrected. Spectral un-mixing was applied to separate each fluorophore's contribution. We have demonstrated that rapid and simultaneous viability measurements on multiple spheroids can be achieved, which will have a significant impact on the prediction of a tumor's response to multiple treatment options. This technique may be applied as well in drug discovery to assess the potential of a drug candidate directly on human primary tissue.

  1. Particle size-shape distributions: the general spheroid problem. I. Mathematical model.

    Science.gov (United States)

    Orive, L M

    1976-08-01

    The development of stereological methods for the study of dilute phases of particles, voids or organelles embedded in a matrix, from measurements made on plane or linear intercepts through the aggregate, has deserved a great deal of effort. With almost no exception, the problem of describing the particulate phase is reduced to that of identifying the statistical distribution--histogram in practice--of a relevant size parameter, with the previous assumption that the particles are modelled by geometrical objects of a constant shape (e.g. spheres). Therefore, particles exhibiting a random variation about a given type of shape as well as a random variation in size, escape previous analyses. Such is the case of unequiaxed particles modelled by triaxial ellipsoids of variable size and eccentricity parameters. It has been conjectured (Moran, 1972) that this problem is indetermined in its generally (i.e. the elliptical sections do not furnish a sufficient information which permits a complete description of the ellipsoids). A proof of this conjecture is given in the Appendix. When the ellipsoids are biaxial (spheroids) and of the same type (prolate or oblate), the problem is identifiable. Previous attempts to solve it assume statistical independence between size and shape. A complete, theoretical solution of the spheroids problem--with the independence condition relaxed--is presented. A number of exact relationships--some of them of a striking simplicity--linking particle properties (e.g. mean-mean caliper length, mean axial ratio, correlation coefficient between principal diameters, etc.) on the one hand, with the major and minor dimensions of the ellipses of section on the other, emerge, and natural, consistent estimators of the mentioned properties are made easily accessible for practical computation. Finally, the scope and limitations of the mathematical model are discussed.

  2. Inverse geometric approach for the simulation of close-to-circular growth. The case of multicellular tumor spheroids

    Science.gov (United States)

    Brutovsky, B.; Horvath, D.; Lisy, V.

    2008-02-01

    We demonstrate the power of genetic algorithms to construct a cellular automata model simulating the growth of 2D close-to-circular clusters, revealing the desired properties, such as the growth rate and, at the same time, the fractal behavior of their contours. The possible application of the approach in the field of tumor modeling is outlined.

  3. Establishment and Characterization of a Tumor Stem Cell-Based Glioblastoma Invasion Model

    DEFF Research Database (Denmark)

    Jensen, Stine Skov; Meyer, Morten; Petterson, Stine Asferg

    2016-01-01

    AIMS: Glioblastoma is the most frequent and malignant brain tumor. Recurrence is inevitable and most likely connected to tumor invasion and presence of therapy resistant stem-like tumor cells. The aim was therefore to establish and characterize a three-dimensional in vivo-like in vitro model taking...... invasion and tumor stemness into account. METHODS: Glioblastoma stem cell-like containing spheroid (GSS) cultures derived from three different patients were established and characterized. The spheroids were implanted in vitro into rat brain slice cultures grown in stem cell medium and in vivo into brains...... of immuno-compromised mice. Invasion was followed in the slice cultures by confocal time-lapse microscopy. Using immunohistochemistry, we compared tumor cell invasion as well as expression of proliferation and stem cell markers between the models. RESULTS: We observed a pronounced invasion into brain slice...

  4. Scaffold-Free Coculture Spheroids of Human Colonic Adenocarcinoma Cells and Normal Colonic Fibroblasts Promote Tumorigenicity in Nude Mice

    Directory of Open Access Journals (Sweden)

    Jong-il Park

    2016-02-01

    Full Text Available The aim of this study was to form a scaffold-free coculture spheroid model of colonic adenocarcinoma cells (CACs and normal colonic fibroblasts (NCFs and to use the spheroids to investigate the role of NCFs in the tumorigenicity of CACs in nude mice. We analysed three-dimensional (3D scaffold-free coculture spheroids of CACs and NCFs. CAC Matrigel invasion assays and tumorigenicity assays in nude mice were performed to examine the effect of NCFs on CAC invasive behaviour and tumorigenicity in 3D spheroids. We investigated the expression pattern of fibroblast activation protein-α (FAP-α by immunohistochemical staining. CAC monocultures did not form densely-packed 3D spheroids, whereas cocultured CACs and NCFs formed 3D spheroids. The 3D coculture spheroids seeded on a Matrigel extracellular matrix showed higher CAC invasiveness compared to CACs alone or CACs and NCFs in suspension. 3D spheroids injected into nude mice generated more and faster-growing tumors compared to CACs alone or mixed suspensions consisting of CACs and NCFs. FAP-α was expressed in NCFs-CACs cocultures and xenograft tumors, whereas monocultures of NCFs or CACs were negative for FAP-α expression. Our findings provide evidence that the interaction between CACs and NCFs is essential for the tumorigenicity of cancer cells as well as for tumor propagation.

  5. Short-term spheroid culture of primary colorectal cancer cells as an in vitro model for personalizing cancer medicine

    DEFF Research Database (Denmark)

    Jeppesen, Maria; Hagel, Grith; Glenthoj, Anders

    2017-01-01

    and no difference in growth rate was observed for spheroids of different sizes. Comparison of spheroids with the original tumour revealed that spheroid culture generally preserved adenocarcinoma histology and expression patterns of cytokeratin 20 and carcinoembryonic antigen. Interestingly, spheroids had a tendency...

  6. Bronchial epithelial spheroids: an alternative culture model to investigate epithelium inflammation-mediated COPD

    Directory of Open Access Journals (Sweden)

    Gangloff Sophie C

    2007-11-01

    Full Text Available Abstract Background Chronic obstructive pulmonary disease (COPD is characterized by abnormal lung inflammation that exceeds the protective response. Various culture models using epithelial cell lines or primary cells have been used to investigate the contribution of bronchial epithelium in the exaggerated inflammation of COPD. However, these models do not mimic in vivo situations for several reasons (e.g, transformed epithelial cells, protease-mediated dissociation of primary cells, etc.. To circumvent these concerns, we developed a new epithelial cell culture model. Methods Using non transformed non dissociated bronchial epithelium obtained by bronchial brushings from COPD and non-COPD smokers, we developed a 3-dimensional culture model, bronchial epithelial spheroids (BES. BES were analyzed by videomicroscopy, light microscopy, immunofluorescence, and transmission electron microscopy. We also compared the inflammatory responses of COPD and non-COPD BES. In our study, we chose to stimulate BES with lipopolycaccharide (LPS and measured the release of the pro-inflammatory mediators interleukin-8 (IL-8 and leukotriene B4 (LTB4 and the anti-inflammatory mediator prostaglandin E2 (PGE2. Results BES obtained from both COPD and non-COPD patients were characterized by a polarized bronchial epithelium with tight junctions and ciliary beating, composed of basal cells, secretory cells and ciliated cells. The ciliary beat frequency of ciliated cells was not significantly different between the two groups. Of interest, BES retained their characteristic features in culture up to 8 days. BES released the inflammatory mediators IL-8, PGE2 and LTB4 constitutively and following exposure to LPS. Interestingly, LPS induced a higher release of IL-8, but not PGE2 and LTB4 in COPD BES (p Conclusion This study provides for the first time a compelling evidence that the BES model provides an unaltered bronchial surface epithelium. More importantly, BES represent an

  7. Elevated CDCP1 predicts poor patient outcome and mediates ovarian clear cell carcinoma by promoting tumor spheroid formation, cell migration and chemoresistance.

    Science.gov (United States)

    He, Y; Wu, A C; Harrington, B S; Davies, C M; Wallace, S J; Adams, M N; Palmer, J S; Roche, D K; Hollier, B G; Westbrook, T F; Hamidi, H; Konecny, G E; Winterhoff, B; Chetty, N P; Crandon, A J; Oliveira, N B; Shannon, C M; Tinker, A V; Gilks, C B; Coward, J I; Lumley, J W; Perrin, L C; Armes, J E; Hooper, J D

    2016-01-28

    Hematogenous metastases are rarely present at diagnosis of ovarian clear cell carcinoma (OCC). Instead dissemination of these tumors is characteristically via direct extension of the primary tumor into nearby organs and the spread of exfoliated tumor cells throughout the peritoneum, initially via the peritoneal fluid, and later via ascites that accumulates as a result of disruption of the lymphatic system. The molecular mechanisms orchestrating these processes are uncertain. In particular, the signaling pathways used by malignant cells to survive the stresses of anchorage-free growth in peritoneal fluid and ascites, and to colonize remote sites, are poorly defined. We demonstrate that the transmembrane glycoprotein CUB-domain-containing protein 1 (CDCP1) has important and inhibitable roles in these processes. In vitro assays indicate that CDCP1 mediates formation and survival of OCC spheroids, as well as cell migration and chemoresistance. Disruption of CDCP1 via silencing and antibody-mediated inhibition markedly reduce the ability of TOV21G OCC cells to form intraperitoneal tumors and induce accumulation of ascites in mice. Mechanistically our data suggest that CDCP1 effects are mediated via a novel mechanism of protein kinase B (Akt) activation. Immunohistochemical analysis also suggested that CDCP1 is functionally important in OCC, with its expression elevated in 90% of 198 OCC tumors and increased CDCP1 expression correlating with poor patient disease-free and overall survival. This analysis also showed that CDCP1 is largely restricted to the surface of malignant cells where it is accessible to therapeutic antibodies. Importantly, antibody-mediated blockade of CDCP1 in vivo significantly increased the anti-tumor efficacy of carboplatin, the chemotherapy most commonly used to treat OCC. In summary, our data indicate that CDCP1 is important in the progression of OCC and that targeting pathways mediated by this protein may be useful for the management of OCC

  8. Stem Cell Spheroids and Ex Vivo Niche Modeling: Rationalization and Scaling-Up.

    Science.gov (United States)

    Chimenti, Isotta; Massai, Diana; Morbiducci, Umberto; Beltrami, Antonio Paolo; Pesce, Maurizio; Messina, Elisa

    2017-04-01

    Improved protocols/devices for in vitro culture of 3D cell spheroids may provide essential cues for proper growth and differentiation of stem/progenitor cells (S/PCs) in their niche, allowing preservation of specific features, such as multi-lineage potential and paracrine activity. Several platforms have been employed to replicate these conditions and to generate S/PC spheroids for therapeutic applications. However, they incompletely reproduce the niche environment, with partial loss of its highly regulated network, with additional hurdles in the field of cardiac biology, due to debated resident S/PCs therapeutic potential and clinical translation. In this contribution, the essential niche conditions (metabolic, geometric, mechanical) that allow S/PCs maintenance/commitment will be discussed. In particular, we will focus on both existing bioreactor-based platforms for the culture of S/PC as spheroids, and on possible criteria for the scaling-up of niche-like spheroids, which could be envisaged as promising tools for personalized cardiac regenerative medicine, as well as for high-throughput drug screening.

  9. Introduction to the level-set full field modeling of laths spheroidization phenomenon in α/β titanium alloys

    Directory of Open Access Journals (Sweden)

    Polychronopoulou D.

    2016-01-01

    Full Text Available Fragmentation of α lamellae and subsequent spheroidization of α laths in α/β titanium alloys occurring during and after deformation are well known phenomena. We will illustrate the development of a new finite element methodology to model them. This new methodology is based on a level set framework to model the deformation and the ad hoc simultaneous and/or subsequent interfaces kinetics. We will focus, at yet, on the modeling of the surface diffusion at the α/β phase interfaces and the motion by mean curvature at the α/α grain interfaces.

  10. Rapid Generation of In Vitro Multicellular Spheroids for the Study of Monoclonal Antibody Therapy

    Directory of Open Access Journals (Sweden)

    Yen T. Phung, Dario Barbone, V. Courtney Broaddus, Mitchell Ho

    2011-01-01

    Full Text Available Tumor microenvironments present significant barriers to penetration by antibodies and immunoconjugates and are difficult to study in vitro. Cells cultured as monolayers typically exhibit less resistance to therapy than those grown in vivo. Therefore, it is important to develop an alternative research model that better represents in vivo tumors. We have developed a protocol to produce multicellular spheroids, a simple and more relevant model of in vivo tumors that allows for further investigations of the microenvironmental effects on drug penetration and tumor cell killing. The protocol is used to produce in vitro three-dimensional tumor spheroids from established human cancer cell lines and primary cancer cells isolated from patients without the use of any extracellular components. To study the ability of tumor-targeting immunoconjugates to penetrate these tumor spheroids in vitro, we have used an immunotoxin targeting mesothelin, a surface protein expressed in malignant mesotheliomas. This method for producing consistent, reproducible 3D spheroids may allow for improved testing of novel monoclonal antibodies and other agents for their ability to penetrate solid tumors for cancer therapy.

  11. Skull base tumor model.

    Science.gov (United States)

    Gragnaniello, Cristian; Nader, Remi; van Doormaal, Tristan; Kamel, Mahmoud; Voormolen, Eduard H J; Lasio, Giovanni; Aboud, Emad; Regli, Luca; Tulleken, Cornelius A F; Al-Mefty, Ossama

    2010-11-01

    Resident duty-hours restrictions have now been instituted in many countries worldwide. Shortened training times and increased public scrutiny of surgical competency have led to a move away from the traditional apprenticeship model of training. The development of educational models for brain anatomy is a fascinating innovation allowing neurosurgeons to train without the need to practice on real patients and it may be a solution to achieve competency within a shortened training period. The authors describe the use of Stratathane resin ST-504 polymer (SRSP), which is inserted at different intracranial locations to closely mimic meningiomas and other pathological entities of the skull base, in a cadaveric model, for use in neurosurgical training. Silicone-injected and pressurized cadaveric heads were used for studying the SRSP model. The SRSP presents unique intrinsic metamorphic characteristics: liquid at first, it expands and foams when injected into the desired area of the brain, forming a solid tumorlike structure. The authors injected SRSP via different passages that did not influence routes used for the surgical approach for resection of the simulated lesion. For example, SRSP injection routes included endonasal transsphenoidal or transoral approaches if lesions were to be removed through standard skull base approach, or, alternatively, SRSP was injected via a cranial approach if the removal was planned to be via the transsphenoidal or transoral route. The model was set in place in 3 countries (US, Italy, and The Netherlands), and a pool of 13 physicians from 4 different institutions (all surgeons and surgeons in training) participated in evaluating it and provided feedback. All 13 evaluating physicians had overall positive impressions of the model. The overall score on 9 components evaluated--including comparison between the tumor model and real tumor cases, perioperative requirements, general impression, and applicability--was 88% (100% being the best possible

  12. Multicellular Self-Assembled Spheroidal Model of the Blood Brain Barrier

    OpenAIRE

    Urich, Eduard; Patsch, Christoph; Aigner, Stefan; Graf, Martin; Iacone, Roberto; Freskg?rd, Per-Ola

    2013-01-01

    The blood brain barrier (BBB) has evolved unique characteristics such as dense coverage of the endothelial cells by pericytes and interactions with astrocytes through perivascular endfeet. We study BBB formation in a 3-dimensional multicellular spheroid system of human primary brain endothelial cells (hpBECs), primary pericytes (hpPs) and primary astrocytes (hpAs). We show for the first time that hpBECs, hpPs and hpAs spontaneously self-organize into a defined multicellular structure which re...

  13. Implantation of glioblastoma spheroids into organotypic brain slice cultures as a model for investigating effects of irradiation

    DEFF Research Database (Denmark)

    Petterson, Stine Asferg; Jakobsen, Ida Pind; Jensen, Stine Skov

    2016-01-01

    Glioblastoma is the most frequent malignant brain tumor with an overall survival of only 14.6 months. Novel in vitro models preserving both tumor tissue and the interface between tumor and brain tissue are highly needed in order to develop novel efficient therapeutic strategies. Additionally, mod...

  14. Vasodilator-Stimulated Phosphoprotein (VASP) depletion from breast cancer MDA-MB-231 cells inhibits tumor spheroid invasion through downregulation of Migfilin, β-catenin and urokinase-plasminogen activator (uPA)

    Energy Technology Data Exchange (ETDEWEB)

    Gkretsi, Vasiliki; Stylianou, Andreas; Stylianopoulos, Triantafyllos, E-mail: tstylian@ucy.ac.cy

    2017-03-15

    A hallmark of cancer cells is their ability to invade surrounding tissues and form metastases. Cell-extracellular matrix (ECM)-adhesion proteins are crucial in metastasis, connecting tumor ECM with actin cytoskeleton thus enabling cells to respond to mechanical cues. Vasodilator-stimulated phosphoprotein (VASP) is an actin-polymerization regulator which interacts with cell-ECM adhesion protein Migfilin, and regulates cell migration. We compared VASP expression in MCF-7 and MDA-MB-231 breast cancer (BC) cells and found that more invasive MDA-MB-231 cells overexpress VASP. We then utilized a 3-dimensional (3D) approach to study metastasis in MDA-MB-231 cells using a system that considers mechanical forces exerted by the ECM. We prepared 3D collagen I gels of increasing concentration, imaged them by atomic force microscopy, and used them to either embed cells or tumor spheroids, in the presence or absence of VASP. We show, for the first time, that VASP silencing downregulated Migfilin, β-catenin and urokinase plasminogen activator both in 2D and 3D, suggesting a matrix-independent mechanism. Tumor spheroids lacking VASP demonstrated impaired invasion, indicating VASP’s involvement in metastasis, which was corroborated by Kaplan-Meier plotter showing high VASP expression to be associated with poor remission-free survival in lymph node-positive BC patients. Hence, VASP may be a novel BC metastasis biomarker. - Highlights: • More invasive MDA-MB-231 overexpress VASP compared to MCF-7 breast cancer cells. • We prepared 3D collagen I gels of increasing concentration and characterized them. • VASP silencing downregulated Migfilin, β-catenin and uPA both in 2D and 3D culture. • Tumor spheroids lacking VASP demonstrated impaired invasion. • Kaplan-Meier plotter shows association of high VASP expression with poor survival.

  15. Antiproliferative Activity and Cellular Uptake of Evodiamine and Rutaecarpine Based on 3D Tumor Models

    Directory of Open Access Journals (Sweden)

    Hui Guo

    2016-07-01

    Full Text Available Evodiamine (EVO and rutaecarpine (RUT are promising anti-tumor drug candidates. The evaluation of the anti-proliferative activity and cellular uptake of EVO and RUT in 3D multicellular spheroids of cancer cells would better recapitulate the native situation and thus better reflect an in vivo response to the treatment. Herein, we employed the 3D culture of MCF-7 and SMMC-7721 cells based on hanging drop method and evaluated the anti-proliferative activity and cellular uptake of EVO and RUT in 3D multicellular spheroids, and compared the results with those obtained from 2D monolayers. The drugs’ IC50 values were significantly increased from the range of 6.4–44.1 μM in 2D monolayers to 21.8–138.0 μM in 3D multicellular spheroids, which may be due to enhanced mass barrier and reduced drug penetration in 3D models. The fluorescence of EVO and RUT was measured via fluorescence spectroscopy and the cellular uptake of both drugs was characterized in 2D tumor models. The results showed that the cellular uptake concentrations of RUT increased with increasing drug concentrations. However, the EVO concentrations uptaken by the cells showed only a small change with increasing drug concentrations, which may be due to the different solubility of EVO and Rut in solvents. Overall, this study provided a new vision of the anti-tumor activity of EVO and RUT via 3D multicellular spheroids and cellular uptake through the fluorescence of compounds.

  16. Multicellular self-assembled spheroidal model of the blood brain barrier.

    Science.gov (United States)

    Urich, Eduard; Patsch, Christoph; Aigner, Stefan; Graf, Martin; Iacone, Roberto; Freskgård, Per-Ola

    2013-01-01

    The blood brain barrier (BBB) has evolved unique characteristics such as dense coverage of the endothelial cells by pericytes and interactions with astrocytes through perivascular endfeet. We study BBB formation in a 3-dimensional multicellular spheroid system of human primary brain endothelial cells (hpBECs), primary pericytes (hpPs) and primary astrocytes (hpAs). We show for the first time that hpBECs, hpPs and hpAs spontaneously self-organize into a defined multicellular structure which recapitulates the complex arrangement of the individual cell types in the BBB structure. Pericytes play a crucial role mediating the interaction between hpBECs and hpAs. This process is not dependent on a scaffold support demonstrating that formation and cellular architecture of the BBB is intrinsically programmed within each specific cell type. In a matrigel setup the hpBECs, hpPs and hpAs also undergo self-arrangement to form endothelial tube-like structures tightly covered by hpPs and loosely attached hpAs mainly at the junctions.

  17. Short-term effects of radiation in gliolalstoma spheroids

    DEFF Research Database (Denmark)

    Petterson, Stine Asferg; Jakobsen, Ida Pind; Jensen, Stine Skov

    2016-01-01

    was to investigate the short-term effects of radiation of spheroids containing tumor-initiating stem-like cells. We used a patient-derived glioblastoma stem cell enriched culture (T76) and the standard glioblastoma cell line U87. Primary spheroids were irradiated with doses between 2 and 50 Gy and assessed after two...

  18. Vasodilator-Stimulated Phosphoprotein (VASP) depletion from breast cancer MDA-MB-231 cells inhibits tumor spheroid invasion through downregulation of Migfilin, β-catenin and urokinase-plasminogen activator (uPA).

    Science.gov (United States)

    Gkretsi, Vasiliki; Stylianou, Andreas; Stylianopoulos, Triantafyllos

    2017-03-15

    A hallmark of cancer cells is their ability to invade surrounding tissues and form metastases. Cell-extracellular matrix (ECM)-adhesion proteins are crucial in metastasis, connecting tumor ECM with actin cytoskeleton thus enabling cells to respond to mechanical cues. Vasodilator-stimulated phosphoprotein (VASP) is an actin-polymerization regulator which interacts with cell-ECM adhesion protein Migfilin, and regulates cell migration. We compared VASP expression in MCF-7 and MDA-MB-231 breast cancer (BC) cells and found that more invasive MDA-MB-231 cells overexpress VASP. We then utilized a 3-dimensional (3D) approach to study metastasis in MDA-MB-231 cells using a system that considers mechanical forces exerted by the ECM. We prepared 3D collagen I gels of increasing concentration, imaged them by atomic force microscopy, and used them to either embed cells or tumor spheroids, in the presence or absence of VASP. We show, for the first time, that VASP silencing downregulated Migfilin, β-catenin and urokinase plasminogen activator both in 2D and 3D, suggesting a matrix-independent mechanism. Tumor spheroids lacking VASP demonstrated impaired invasion, indicating VASP's involvement in metastasis, which was corroborated by Kaplan-Meier plotter showing high VASP expression to be associated with poor remission-free survival in lymph node-positive BC patients. Hence, VASP may be a novel BC metastasis biomarker. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Method for the determination of oxygen consumption rates and diffusion coefficients in multicellular spheroids

    OpenAIRE

    Mueller-Klieser, W.

    1984-01-01

    A method has been developed for the quantitative evaluation of oxygen tension (PO2) distributions in multicellular spheroids measured with O2-sensitive microelectrodes. The experimental data showed that multicellular tumor spheroids in stirred growth media were characterized by a diffusion-depleted zone surrounding the spheroids. This zone was elicited by an unstirred layer of medium next to the spheroid leading to a continuous decrease in the PO2 values from the bulk medium towards the spher...

  20. An Explanation of Jupiter's Equatorially Symmetric Gravitational Field using a Four-layer, Non-spheroidal Model with Zonal Flow

    Science.gov (United States)

    Kong, Dali; Zhang, Keke; Schubert, Gerald; Anderson, John

    2017-10-01

    The structure/amplitude of the Jovian equatorially symmetric gravitational field is affected by both rotational distortion and the fast equatorially symmetric zonal flow. We construct a fully self-consistent, four-layer, non-spheroidal (i.e, the shape is irregular) model of Jupiter that comprises an inner core, a metallic region, an outer molecular envelope and a thin transition layer between the metallic and molecular regions. While the core is assumed to have a uniform density, three different equations of state are adopted for the metallic, molecular and transition regions. We solve the governing equations via a perturbation approach. The leading-order problem accounts for the full effect of rotational distortion, and determines the density, size and shape of the core, the location and thickness of the transition layer, and the shape of the 1-bar pressure level; it also produces the mass, the equatorial and polar radii of Jupiter, and the even zonal gravitational coefficients caused by the rotational distortion. The next-order problem determines the corrections caused by the zonal flow which is assumed to be confined within the molecular envelope and on cylinders parallel to the rotation axis. Our model provides the total even gravitational coefficients that can be compared with those acquired by the Juno spacecraft.

  1. Mass Modelling of Dwarf Spheroidal Galaxies: the Effect of Unbound Stars From Tidal Tails And the Milky Way

    Energy Technology Data Exchange (ETDEWEB)

    Klimentowski, Jaroslaw; Lokas, Ewa L.; /Warsaw, Copernicus Astron. Ctr.; Kazantzidis, Stelios; /KIPAC, Menlo Park; Prada, Francisco; /IAA, Granada; Mayer, Lucio; /Zurich,; Mamon, Gary A.; /Paris, Inst. Astrophys. /Meudon Observ.

    2006-11-14

    We study the origin and properties of the population of unbound stars in the kinematic samples of dwarf spheroidal galaxies. For this purpose we have run a high resolution N- body simulation of a two-component dwarf galaxy orbiting in a Milky Way potential. In agreement with the tidal stirring scenario of Mayer et al., the dwarf is placed on a highly eccentric orbit, its initial stellar component is in the form of an exponential disk and it has a NFW-like dark matter halo. After 10 Gyrs of evolution the dwarf produces a spheroidal stellar component and is strongly tidally stripped so that mass follows light and the stars are on almost isotropic orbits. From this final state, we create mock kinematic data sets for 200 stars by observing the dwarf in different directions.We find that when the dwarf is observed along the tidal tails the kinematic samples are strongly contaminated by unbound stars from the tails.We also study another source of possible contamination by adding stars from the Milky Way. We demonstrate that most of the unbound stars can be removed by the method of interloper rejection proposed by den Hartog & Katgert and recently tested on simulated dark matter haloes. We model the cleaned up kinematic samples using solutions of the Jeans equation with constant mass-to-light ratio and velocity anisotropy parameter. We show that even for such strongly stripped dwarf the Jeans analysis, when applied to cleaned samples, allows us to reproduce the mass and mass-to-light ratio of the dwarf with accuracy typically better than 25 percent and almost exactly in the case when the line of sight is perpendicular to the tidal tails. The analysis was applied to the new data for the Fornax dSph galaxy for which we find a mass-to-light ratio of 11 solar units and isotropic orbits. We demonstrate that most of the contamination in the kinematic sample of Fornax probably originates from the Milky Way.

  2. Lethal Effects of Radiation and Platinum Analogues on Multicellular Spheroids of HeLa Cells

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Seong Eon [Kyunghee University College of Medicine, Seoul (Korea, Republic of)

    1989-12-15

    Multicellul ar tumor spheroids of HeLa cells have been grown in a static culture system. Samples of spheroids were exposed for 2 h to graded concentration of sis-platinum and its analogue, carboplatin, and then response assayed by survival of clonogenic cells. The purpose of present experiment is to clarify the effectiveness of these platinum compounds and to evaluate intrinsic radiosensitivity of cells using spheroids of HeLa cells as an experimental in vitro model. Variations of the drug sensitivity of monolayers as well as spheroids were also evaluated in cell-survival curves. In cia-platinum concentration-survival cutie, there was a large shoulder extending as far as Cq=3.4 mM, after which there was exponential decrease in survival curve having a Co Value of 1,2 {mu}M in spheroids. While the Co for the spheroids was essentially no significant change, but Cq value was larger than that of monolayers. This suggest that the effect of cis-platinum is greater in the monolayer with actively proliferating cells than hypoxic one. In the carboplatin concentration-survival curves, the Co value of spheroids was 15.0 mM and the ratio with the Co from monolayer cell (32.5 mM) was 0.46, thus indicating that the spheroids had a greater sensitivity to carboplatin than monolayers. Therefore, the effect of carboplatin is mainly on the deeper layers of spheroids acting as hypoxic cell sensitizer. The enhanced effect was obtained for monolayer cells using combined X-ray and carboplatin treatment 2 hours before irradiation. The result shown in isobologram analysis for the level of surviving fraction at 0.01 indicated that the effect of two agents was truly supra-additive. From this experimental data, carboplatin has excited much receipt interest as one of the most promising, since it is almost without nephrotoxicity and causes less gastrointestinal toxicity than cia-platinum. Interaction between carboplatin and radiation might play an important role for more effective local tumor

  3. Experimental rat lung tumor model with intrabronchial tumor cell implantation.

    Science.gov (United States)

    Gomes Neto, Antero; Simão, Antônio Felipe Leite; Miranda, Samuel de Paula; Mourão, Lívia Talita Cajaseiras; Bezerra, Nilfácio Prado; Almeida, Paulo Roberto Carvalho de; Ribeiro, Ronaldo de Albuquerque

    2008-01-01

    The objective of this study was to develop a rat lung tumor model for anticancer drug testing. Sixty-two female Wistar rats weighing 208 +/- 20 g were anesthetized intraperitoneally with 2.5% tribromoethanol (1 ml/100 g live weight), tracheotomized and intubated with an ultrafine catheter for inoculation with Walker's tumor cells. In the first step of the experiment, a technique was established for intrabronchial implantation of 10(5) to 5 x 10(5) tumor cells, and the tumor take rate was determined. The second stage consisted of determining tumor volume, correlating findings from high-resolution computed tomography (HRCT) with findings from necropsia and determining time of survival. The tumor take rate was 94.7% for implants with 4 x 10(5) tumor cells, HRCT and necropsia findings matched closely (r=0.953; p<0.0001), the median time of survival was 11 days, and surgical mortality was 4.8%. The present rat lung tumor model was shown to be feasible: the take rate was high, surgical mortality was negligible and the procedure was simple to perform and easily reproduced. HRCT was found to be a highly accurate tool for tumor diagnosis, localization and measurement and may be recommended for monitoring tumor growth in this model.

  4. Development and characterization of a spheroidal coculture model of endothelial cells and fibroblasts for improving angiogenesis in tissue engineering

    DEFF Research Database (Denmark)

    Wenger, Andreas; Kowalewski, Nadja; Stahl, Andreas

    2005-01-01

    and a peripheral localization of fibroblasts. In coculture spheroids, the level of apoptosis of endothelial cells was strongly decreased upon cocultivation with fibroblasts. Collagen-embedded HUVEC spheroids develop numerous lumenized capillary-like sprouts. This was also apparent for HUVEC/hFB cospheroids, albeit...... to a lesser extent. Quantification of cumulative sprout length revealed an approximately 35% reduction in endothelial cell sprouting upon cocultivation with fibroblasts in cospheroids. The slight reduction in endothelial cell sprouting was not mediated by a paracrine mechanism but is most likely due...

  5. Unsuccessful mitosis in multicellular tumour spheroids.

    Science.gov (United States)

    Molla, Annie; Couvet, Morgane; Coll, Jean-Luc

    2017-04-25

    Multicellular spheroids are very attractive models in oncology because they mimic the 3D organization of the tumour cells with their microenvironment. We show here using 3 different cell types (mammary TSA/pc, embryonic kidney Hek293 and cervical cancer HeLa), that when the cells are growing as spheroids the frequency of binucleated cells is augmented as occurs in some human tumours.We therefore describe mitosis in multicellular spheroids by following mitotic markers and by time-lapse experiments. Chromosomes alignment appears to be correct on the metaphasic plate and the passenger complex is well localized on centromere. Moreover aurora kinases are fully active and histone H3 is phosphorylated on Ser 10. Consequently, the mitotic spindle checkpoint is satisfied and, anaphase proceeds as illustrated by the transfer of survivin on the spindle and by the segregation of the two lots of chromosomes. However, the segregation plane is not well defined and oscillations of the dividing cells are observed. Finally, cytokinesis fails and the absence of separation of the two daughter cells gives rise to binucleated cells.Division orientation is specified during interphase and persists throughout mitosis. Our data indicate that the cancer cells, in multicellular spheroids, lose their ability to regulate their orientation, a feature commonly encountered in tumours.Moreover, multicellular spheroid expansion is still sensitive to mitotic drugs as pactlitaxel and aurora kinase inhibitors. The spheroids thus represent a highly relevant model for studying drug efficiency in tumours.

  6. Magnetically levitated mesenchymal stem cell spheroids cultured with a collagen gel maintain phenotype and quiescence

    Directory of Open Access Journals (Sweden)

    Natasha S Lewis

    2017-04-01

    Full Text Available Multicellular spheroids are an established system for three-dimensional cell culture. Spheroids are typically generated using hanging drop or non-adherent culture; however, an emerging technique is to use magnetic levitation. Herein, mesenchymal stem cell spheroids were generated using magnetic nanoparticles and subsequently cultured within a type I collagen gel, with a view towards developing a bone marrow niche environment. Cells were loaded with magnetic nanoparticles, and suspended beneath an external magnet, inducing self-assembly of multicellular spheroids. Cells in spheroids were viable and compared to corresponding monolayer controls, maintained stem cell phenotype and were quiescent. Interestingly, core spheroid necrosis was not observed, even with increasing spheroid size, in contrast to other commonly used spheroid systems. This mesenchymal stem cell spheroid culture presents a potential platform for modelling in vitro bone marrow stem cell niches, elucidating interactions between cells, as well as a useful model for drug delivery studies.

  7. An in vivo-like tumor stem cell-related glioblastoma in vitro model for drug discovery

    DEFF Research Database (Denmark)

    Jensen, Stine Skov; Aaberg-Jessen, Charlotte; Nørregaard, Annette

    the effects of new drugs on tumor cells including tumor stem cells. Implantation of glioblastoma cells into organotypic brain slice cultures has previously been published as a model system, but not using a stem cell favourable environment. Organotypic corticostriatal rat brain slice cultures were prepared...... and cultured in a serum containing medium replaced after three days with a serum-free stem cell medium. Thereafter fluorescent DiI labelled glioblastoma spheroids from the cell line U87 and the tumor stem cell line SJ-1 established in our laboratory were implanted into the brain slices between cortex......The discovery of tumor stem cells being highly resistant against therapy makes new demands to model systems suitable for evaluation of the effects of new drugs on tumor stem cells. The aim of the present study was therefore to develop an in vivo-like in vitro glioblastoma model for testing...

  8. Misorientations in spheroidal graphite: some new insights about spheroidal graphite growth in cast irons

    Science.gov (United States)

    Lacaze, J.; Theuwissen, K.; Laffont, L.; Véron, M.

    2016-03-01

    Local diffraction patterning, orientation mapping and high resolution transmission electron microscopy imaging have been used to characterize misorientations in graphite spheroids of cast irons. Emphasis is put here on bulk graphite, away from the nucleus as well as from the outer surface of the spheroids in order to get information on their growth during solidification. The results show that spheroidal graphite consists in conical sectors made of elementary blocks piled up on each other. These blocks are elongated along the prismatic a direction of graphite with the c axes roughly parallel to the radius of the spheroids. This implies that the orientation of the blocks rotates around the spheroid centre giving low angle tilting misorientations along tangential direction within each sector. Misorientations between neighbouring sectors are of higher values and their interfaces show rippled layers which are characteristic of defects in graphene. Along a radius of the spheroid, clockwise and anticlockwise twisting between blocks is observed. These observations help challenging some of the models proposed to explain spheroidal growth in cast ions.

  9. Long-term culture of organotypic multicellular glioma spheroids: a good culture model for studying gliomas

    NARCIS (Netherlands)

    Kaaijk, P.; Troost, D.; Das, P. K.; Leenstra, S.; Bosch, D. A.

    1995-01-01

    Gliomas, as well as other solid tumours, contain tumour stroma composed of connective tissue, macrophages, capillaries and other non-cellular constituents. Therefore, a homogeneous culture of tumour cells alone, as is often used as a culture model for gliomas, is not ideal to study all aspects of

  10. Effect of apoptosis and response of extracellular matrix proteins after chemotherapy application on human breast cancer cell spheroids.

    Science.gov (United States)

    Oktem, G; Vatansever, S; Ayla, S; Uysal, A; Aktas, S; Karabulut, B; Bilir, A

    2006-02-01

    Multicellular tumor spheroid (MTS) represents a three-dimensional structural form of tumors in laboratory conditions, and it has the characteristics of avascular micrometastases or intervascular spaces of big tumors. Recent studies indicate that extracellular matrix (ECM) proteins play a critical role in tumor metastasis, therefore normal and cancer cells require an ECM for survival, proliferation and differentiation. Doxorubicin and Docetaxel are widely used in the therapy of breast cancer, as well as in in vivo and in vitro studies. In this study, we examined the effect of apoptosis and proliferation of cells on the human breast cancer cell line, MCF-7, by using p53, bcl-2 and Ki67 gene expression, and the tendency to metastasis with extracellular matrix proteins, laminin and type IV collagen after chemotherapy in the spheroid model. The apoptotic cell death in situ was detected by TUNEL method. TUNEL-positive cells and positive immunoreactivities of laminin, type IV collagen, p53 and, bcl-2 were detected in the control group. There was no laminin and type IV collagen immunoreactivities in spheroids of drug groups. While TUNEL-positive cells and p53 immunoreactivity were detected in Docetaxel, Doxorubicin and Docetaxel/Doxorubicin groups, p53 immunoreactivity was not observed in the Docetaxel group. There was no bcl-2 immunoreactivity in either drug group. In addition, we did not detect Ki67 immunoreactivity in both control and drug treatment groups. However, the absence of Ki67 protein in MCF-7 breast multicellular tumor spheroids is possibly related to the cells in G0 or S phase. These chemotherapeutic agents may affect the presence of ECM proteins in this in vitro model of micrometastasis of spheroids. These findings suggest that the possible mechanism of cell death in Doxorubicin and Docetaxel/Doxorubicin treatment groups is related to apoptosis through the p53 pathway. However, we considered the possibility that there is another control mechanism for the

  11. 3D cell culture systems modeling tumor growth determinants in cancer target discovery.

    Science.gov (United States)

    Thoma, Claudio R; Zimmermann, Miriam; Agarkova, Irina; Kelm, Jens M; Krek, Wilhelm

    2014-04-01

    Phenotypic heterogeneity of cancer cells, cell biological context, heterotypic crosstalk and the microenvironment are key determinants of the multistep process of tumor development. They sign responsible, to a significant extent, for the limited response and resistance of cancer cells to molecular-targeted therapies. Better functional knowledge of the complex intra- and intercellular signaling circuits underlying communication between the different cell types populating a tumor tissue and of the systemic and local factors that shape the tumor microenvironment is therefore imperative. Sophisticated 3D multicellular tumor spheroid (MCTS) systems provide an emerging tool to model the phenotypic and cellular heterogeneity as well as microenvironmental aspects of in vivo tumor growth. In this review we discuss the cellular, chemical and physical factors contributing to zonation and cellular crosstalk within tumor masses. On this basis, we further describe 3D cell culture technologies for growth of MCTS as advanced tools for exploring molecular tumor growth determinants and facilitating drug discovery efforts. We conclude with a synopsis on technological aspects for on-line analysis and post-processing of 3D MCTS models. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Microencapsulated tumor assay: Evaluation of the nude mouse model of pancreatic cancer

    Science.gov (United States)

    Ma, Ming-Zhe; Cheng, Dong-Feng; Ye, Jin-Hua; Zhou, Yong; Wang, Jia-Xiang; Shi, Min-Min; Han, Bao-San; Peng, Cheng-Hong

    2012-01-01

    AIM: To establish a more stable and accurate nude mouse model of pancreatic cancer using cancer cell microencapsulation. METHODS: The assay is based on microencapsulation technology, wherein human tumor cells are encapsulated in small microcapsules (approximately 420 μm in diameter) constructed of semipermeable membranes. We implemented two kinds of subcutaneous implantation models in nude mice using the injection of single tumor cells and encapsulated pancreatic tumor cells. The size of subcutaneously implanted tumors was observed on a weekly basis using two methods, and growth curves were generated from these data. The growth and metastasis of orthotopically injected single tumor cells and encapsulated pancreatic tumor cells were evaluated at four and eight weeks postimplantation by positron emission tomography-computed tomography scan and necropsy. The pancreatic tumor samples obtained from each method were then sent for pathological examination. We evaluated differences in the rates of tumor incidence and the presence of metastasis and variations in tumor volume and tumor weight in the cancer microcapsules vs single-cell suspensions. RESULTS: Sequential in vitro observations of the microcapsules showed that the cancer cells in microcapsules proliferated well and formed spheroids at days 4 to 6. Further in vitro culture resulted in bursting of the membrane of the microcapsules and cells deviated outward and continued to grow in flasks. The optimum injection time was found to be 5 d after tumor encapsulation. In the subcutaneous implantation model, there were no significant differences in terms of tumor volume between the encapsulated pancreatic tumor cells and cells alone and rate of tumor incidence. There was a significant difference in the rate of successful implantation between the cancer cell microencapsulation group and the single tumor-cell suspension group (100% vs 71.43%, respectively, P = 0.0489) in the orthotropic implantation model. The former method

  13. Decrease in paracellular permeability and chemosensitivity to doxorubicin by claudin-1 in spheroid culture models of human lung adenocarcinoma A549 cells.

    Science.gov (United States)

    Akizuki, Risa; Maruhashi, Ryohei; Eguchi, Hiroaki; Kitabatake, Kazuki; Tsukimoto, Mitsutoshi; Furuta, Takumi; Matsunaga, Toshiyuki; Endo, Satoshi; Ikari, Akira

    2018-03-07

    Chemotherapy resistance is a major problem in the treatment of cancer, but the underlying mechanisms are not fully understood. We found that the expression levels of claudin-1 (CLDN1) and 3, tight junctional proteins, are upregulated in cisplatin (CDDP)-resistant human lung adenocarcinoma A549 (A549R) cells. A549R cells showed cross-resistance to doxorubicin (DXR). Here, the expression mechanism and function of CLDN1 and 3 were examined. CLDN1 and 3 were mainly localized at tight junctions concomitant with zonula occludens (ZO)-1, a scaffolding protein, in A549 and A549R cells. The phosphorylation levels of Src, MEK, ERK, c-Fos, and Akt in A549R cells were higher than those in A549 cells. The expression levels of CLDN1 and 3 were decreased by LY-294002, a phosphoinositide 3-kinase (PI3K) inhibitor, and BAY 11-7082, an NF-κB inhibitor. The overexpression of CLDN1 and 3 decreased the paracellular permeability of DXR in A549 cells. Hypoxia levels in A549R and CLDN1-overexpressing cells (CLDN1/A549) were greater than those in A549, mock/A549, and CLDN3/A549 cells in a spheroid culture model. In contrast, accumulation in the region inside the spheroids and the toxicity of DXR in A549R and CLDN1/A549 cells were lower than those in other cells. Furthermore, the accumulation and toxicity of DXR were rescued by CLDN1 siRNA in A549R cells. We suggest that CLDN1 is upregulated by CDDP resistance through activation of a PI3K/Akt/NF-κB pathway, resulting in the inhibition of penetration of anticancer drugs into the inner area of spheroids. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. Advances in multicellular spheroids formation.

    Science.gov (United States)

    Cui, X; Hartanto, Y; Zhang, H

    2017-02-01

    Three-dimensional multicellular spheroids (MCSs) have a complex architectural structure, dynamic cell-cell/cell-matrix interactions and bio-mimicking in vivo microenvironment. As a fundamental building block for tissue reconstruction, MCSs have emerged as a powerful tool to narrow down the gap between the in vitro and in vivo model. In this review paper, we discussed the structure and biology of MCSs and detailed fabricating methods. Among these methods, the approach in microfluidics with hydrogel support for MCS formation is promising because it allows essential cell-cell/cell-matrix interactions in a confined space. © 2017 The Author(s).

  15. Mathematical Modeling of Tumor-Tumor Distant Interactions Supports a Systemic Control of Tumor Growth.

    Science.gov (United States)

    Benzekry, Sebastien; Lamont, Clare; Barbolosi, Dominique; Hlatky, Lynn; Hahnfeldt, Philip

    2017-09-15

    Interactions between different tumors within the same organism have major clinical implications, especially in the context of surgery and metastatic disease. Three main explanatory theories (competition, angiogenesis inhibition, and proliferation inhibition) have been proposed, but precise determinants of the phenomenon remain poorly understood. Here, we formalized these theories into mathematical models and performed biological experiments to test them with empirical data. In syngeneic mice bearing two simultaneously implanted tumors, growth of only one of the tumors was significantly suppressed (61% size reduction at day 15, P < 0.05). The competition model had to be rejected, whereas the angiogenesis inhibition and proliferation inhibition models were able to describe the data. Additional models including a theory based on distant cytotoxic log-kill effects were unable to fit the data. The proliferation inhibition model was identifiable and minimal (four parameters), and its descriptive power was validated against the data, including consistency in predictions of single tumor growth when no secondary tumor was present. This theory may also shed new light on single cancer growth insofar as it offers a biologically translatable picture of how local and global action may combine to control local tumor growth and, in particular, the role of tumor-tumor inhibition. This model offers a depiction of concomitant resistance that provides an improved theoretical basis for tumor growth control and may also find utility in therapeutic planning to avoid postsurgery metastatic acceleration. Cancer Res; 77(18); 5183-93. ©2017 AACR . ©2017 American Association for Cancer Research.

  16. Inflammatory Cytokine Tumor Necrosis Factor α Confers Precancerous Phenotype in an Organoid Model of Normal Human Ovarian Surface Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Joseph Kwong

    2009-06-01

    Full Text Available In this study, we established an in vitro organoid model of normal human ovarian surface epithelial (HOSE cells. The spheroids of these normal HOSE cells resembled epithelial inclusion cysts in human ovarian cortex, which are the cells of origin of ovarian epithelial tumor. Because there are strong correlations between chronic inflammation and the incidence of ovarian cancer, we used the organoid model to test whether protumor inflammatory cytokine tumor necrosis factor α would induce malignant phenotype in normal HOSE cells. Prolonged treatment of tumor necrosis factor α induced phenotypic changes of the HOSE spheroids, which exhibited the characteristics of precancerous lesions of ovarian epithelial tumors, including reinitiation of cell proliferation, structural disorganization, epithelial stratification, loss of epithelial polarity, degradation of basement membrane, cell invasion, and overexpression of ovarian cancer markers. The result of this study provides not only an evidence supporting the link between chronic inflammation and ovarian cancer formation but also a relevant and novel in vitro model for studying of early events of ovarian cancer.

  17. Vorinostat eliminates multicellular resistance of mesothelioma 3D spheroids via restoration of Noxa expression.

    Directory of Open Access Journals (Sweden)

    Dario Barbone

    Full Text Available When grown in 3D cultures as spheroids, mesothelioma cells acquire a multicellular resistance to apoptosis that resembles that of solid tumors. We have previously found that resistance to the proteasome inhibitor bortezomib in 3D can be explained by a lack of upregulation of Noxa, the pro-apoptotic BH3 sensitizer that acts via displacement of the Bak/Bax-activator BH3-only protein, Bim. We hypothesized that the histone deacetylase inhibitor vorinostat might reverse this block to Noxa upregulation in 3D. Indeed, we found that vorinostat effectively restored upregulation of Noxa protein and message and abolished multicellular resistance to bortezomib in the 3D spheroids. The ability of vorinostat to reverse resistance was ablated by knockdown of Noxa or Bim, confirming the essential role of the Noxa/Bim axis in the response to vorinostat. Addition of vorinostat similarly increased the apoptotic response to bortezomib in another 3D model, the tumor fragment spheroid, which is grown from human mesothelioma ex vivo. In addition to its benefit when used with bortezomib, vorinostat also enhanced the response to cisplatin plus pemetrexed, as shown in both 3D models. Our results using clinically relevant 3D models show that the manipulation of the core apoptotic repertoire may improve the chemosensitivity of mesothelioma. Whereas neither vorinostat nor bortezomib alone has been clinically effective in mesothelioma, vorinostat may undermine chemoresistance to bortezomib and to other therapies thereby providing a rationale for combinatorial strategies.

  18. Vorinostat Eliminates Multicellular Resistance of Mesothelioma 3D Spheroids via Restoration of Noxa Expression

    Science.gov (United States)

    Barbone, Dario; Cheung, Priscilla; Battula, Sailaja; Busacca, Sara; Gray, Steven G.; Longley, Daniel B.; Bueno, Raphael; Sugarbaker, David J.; Fennell, Dean A.; Broaddus, V. Courtney

    2012-01-01

    When grown in 3D cultures as spheroids, mesothelioma cells acquire a multicellular resistance to apoptosis that resembles that of solid tumors. We have previously found that resistance to the proteasome inhibitor bortezomib in 3D can be explained by a lack of upregulation of Noxa, the pro-apoptotic BH3 sensitizer that acts via displacement of the Bak/Bax-activator BH3-only protein, Bim. We hypothesized that the histone deacetylase inhibitor vorinostat might reverse this block to Noxa upregulation in 3D. Indeed, we found that vorinostat effectively restored upregulation of Noxa protein and message and abolished multicellular resistance to bortezomib in the 3D spheroids. The ability of vorinostat to reverse resistance was ablated by knockdown of Noxa or Bim, confirming the essential role of the Noxa/Bim axis in the response to vorinostat. Addition of vorinostat similarly increased the apoptotic response to bortezomib in another 3D model, the tumor fragment spheroid, which is grown from human mesothelioma ex vivo. In addition to its benefit when used with bortezomib, vorinostat also enhanced the response to cisplatin plus pemetrexed, as shown in both 3D models. Our results using clinically relevant 3D models show that the manipulation of the core apoptotic repertoire may improve the chemosensitivity of mesothelioma. Whereas neither vorinostat nor bortezomib alone has been clinically effective in mesothelioma, vorinostat may undermine chemoresistance to bortezomib and to other therapies thereby providing a rationale for combinatorial strategies. PMID:23300762

  19. Development of controlled release spheroids using Buchananiacochinchinesis gum

    Directory of Open Access Journals (Sweden)

    Narayan Babulal Gaikwad

    2013-03-01

    Full Text Available Chirauli nut gum was isolated from the bark of Buchanania cochinchinesis (fam. Anacadiacea and was used as a release modifier for the preparation of Diclofenac sodium spheroids using the extrusion spheronization technique. The process was studied for the effects on variables when making spheroids with satisfactory particle shape, size and size distribution. The prepared spheroids were characterized for surface morphology, qualitative surface porosity, friability, bulk density and flow properties. In vitro studies demonstrated that the release exhibited Fickian diffusion kinetics which was confirmed by the Higuchi and the Korsmeyer-Peppas models. The physico-chemical parameters of the gum could be correlated to the in vitro dissolution profile of the spheroids. The spheroids were not able to sustain the drug releases over 12 hours. A greater concentration of Chirauli nut gum and a process that can accommodate such greater concentrations may produce a formulation capable of significant sustained release.

  20. Prolate spheroidal quantum cloak

    Energy Technology Data Exchange (ETDEWEB)

    Syue, Cheng-De; Lin, De-Hone, E-mail: dhlin@mail.nsysu.edu.tw [Department of Physics, National Sun Yat-sen University, Kaohsiung, Taiwan (China)

    2015-04-15

    To understand the propagation behavior of an oblique incident matter wave in a three-dimensional non-spherical quantum cloak, we perform the transformation design for the prolate spheroidal coordinate system and obtain a quantum cloak with an ellipsoidal shape. The mass parameters and effective potential for the creation of a perfect prolate spheroidal invisibility region are given. The analytic representations of the cloaked matter wave and probability current in the cloaking shell are presented. Special attention is paid to the discussions of the probability current in the cloaking shell for only that current can manifestly exhibit how the wave vector of the matter wave is curved, rotated, and guided in the cloaking shell to flow around the non-spherically invisible region. With the current analysis, one shows that the presented cloak can perfectly guide the matter wave in the situation of any oblique incidence. The proposed prolate spheroidal cloak for matter waves provides the first non-spherically three-dimensional setup for quantum cloaking.

  1. Ovarian tumor attachment, invasion and vascularization reflect unique microenvironments in the peritoneum:Insights from xenograft and mathematical models

    Directory of Open Access Journals (Sweden)

    Mara P. Steinkamp

    2013-05-01

    Full Text Available Ovarian cancer relapse is often characterized by metastatic spread throughout the peritoneal cavity with tumors attached to multiple organs. In this study, interaction of ovarian tumor cells with the peritoneal tumor microenvironment was evaluated in a xenograft model based on intraperitoneal injection of fluorescent SKOV3.ip1 ovarian cancer cells. Intra-vital microscopy of mixed GFP-RFP cell populations injected into the peritoneum demonstrated that tumor cells aggregate and attach as mixed spheroids, emphasizing the importance of homotypic adhesion in tumor formation. Electron microscopy provided high resolution structural information about local attachment sites. Experimental measurements from the mouse model were used to build a three-dimensional cellular Potts ovarian tumor model (OvTM that examines ovarian tumor cell attachment, chemotaxis, growth and vascularization. OvTM simulations provide insight into the relative influence of tumor cell-cell adhesion, oxygen availability, and local architecture on tumor growth and morphology. Notably, tumors on the mesentery, omentum or spleen readily invade the open architecture, while tumors attached to the gut encounter barriers that restrict invasion and instead rapidly expand into the peritoneal space. Simulations suggest that rapid neovascularization of SKOV3.ip1 tumors is triggered by constitutive release of angiogenic factors in the absence of hypoxia. This research highlights the importance of cellular adhesion and tumor microenvironment in the seeding of secondary ovarian tumors on diverse organs within the peritoneal cavity. Results of the OvTM simulations indicate that invasion is strongly influenced by features underlying the mesothelial lining at different sites, but is also affected by local production of chemotactic factors. The integrated in vivo mouse model and computer simulations provide a unique platform for evaluating targeted therapies for ovarian cancer relapse.

  2. Dielectric spectroscopy platform to measure MCF10A epithelial cell aggregation as a model for spheroidal cell cluster analysis.

    Science.gov (United States)

    Heileman, K L; Tabrizian, M

    2017-05-02

    3-Dimensional cell cultures are more representative of the native environment than traditional cell cultures on flat substrates. As a result, 3-dimensional cell cultures have emerged as a very valuable model environment to study tumorigenesis, organogenesis and tissue regeneration. Many of these models encompass the formation of cell aggregates, which mimic the architecture of tumor and organ tissue. Dielectric impedance spectroscopy is a non-invasive, label free and real time technique, overcoming the drawbacks of established techniques to monitor cell aggregates. Here we introduce a platform to monitor cell aggregation in a 3-dimensional extracellular matrix using dielectric spectroscopy. The MCF10A breast epithelial cell line serves as a model for cell aggregation. The platform maintains sterile conditions during the multi-day assay while allowing continuous dielectric spectroscopy measurements. The platform geometry optimizes dielectric measurements by concentrating cells within the electrode sensing region. The cells show a characteristic dielectric response to aggregation which corroborates with finite element analysis computer simulations. By fitting the experimental dielectric spectra to the Cole-Cole equation, we demonstrated that the dispersion intensity Δε and the characteristic frequency f c are related to cell aggregate growth. In addition, microscopy can be performed directly on the platform providing information about cell position, density and morphology. This platform could yield many applications for studying the electrophysiological activity of cell aggregates.

  3. An in vivo-like tumor stem cell-related glioblastoma in vitro model for drug discovery

    DEFF Research Database (Denmark)

    Jensen, Stine Skov; Aaberg-Jessen, Charlotte; Nørregaard, Annette

    the effects of new drugs on tumor cells including tumor stem cells. Implantation of glioblastoma cells into organotypic brain slice cultures has previously been published as a model system, but not using a stem cell favourable environment. Organotypic corticostriatal rat brain slice cultures were prepared...... and cultured in a serum containing medium replaced after three days with a serum-free stem cell medium. Thereafter fluorescent DiI labelled glioblastoma spheroids from the cell line U87 and the tumor stem cell line SJ-1 established in our laboratory were implanted into the brain slices between cortex...... growth of the U87 implants, but no invasion of cells into the brain tissue, neither in vitro nor in vivo. In contrast, SJ-1 was clearly invasive both in vitro and in vivo, but not very expansive. The co-cultures and brains with xenografts were immunohistochemically stained with anti-human vimentin...

  4. Comparison of Spheroidal Carbonaceous Particle Data with Modelled Atmospheric Black Carbon Concentration and Deposition and Air Mass Sources in Northern Europe, 1850–2010

    Directory of Open Access Journals (Sweden)

    Meri Ruppel

    2013-01-01

    Full Text Available Spheroidal carbonaceous particles (SCP are a well-defined fraction of black carbon (BC, produced only by the incomplete combustion of fossil fuels such as coal and oil. Their past concentrations have been studied using environmental archives, but, additionally, historical trends of BC concentration and deposition can be estimated by modelling. These models are based on BC emission inventories, but actual measurements of BC concentration and deposition play an essential role in their evaluation and validation. We use the chemistry transport model OsloCTM2 to model historical time series of BC concentration and deposition from energy and industrial sources and compare these to sedimentary measurements of SCPs obtained from lake sediments in Northern Europe from 1850 to 2010. To determine the origin of SCPs we generated back trajectories of air masses to the study sites. Generally, trends of SCP deposition and modelled results agree reasonably well, showing rapidly increasing values from 1950, to a peak in 1980, and a decrease towards the present. Empirical SCP data show differences in deposition magnitude between the sites that are not captured by the model but which may be explained by different air mass transport patterns. The results highlight the need for numerous observational records to reliably validate model results.

  5. In silico modeling for tumor growth visualization.

    Science.gov (United States)

    Jeanquartier, Fleur; Jean-Quartier, Claire; Cemernek, David; Holzinger, Andreas

    2016-08-08

    Cancer is a complex disease. Fundamental cellular based studies as well as modeling provides insight into cancer biology and strategies to treatment of the disease. In silico models complement in vivo models. Research on tumor growth involves a plethora of models each emphasizing isolated aspects of benign and malignant neoplasms. Biologists and clinical scientists are often overwhelmed by the mathematical background knowledge necessary to grasp and to apply a model to their own research. We aim to provide a comprehensive and expandable simulation tool to visualizing tumor growth. This novel Web-based application offers the advantage of a user-friendly graphical interface with several manipulable input variables to correlate different aspects of tumor growth. By refining model parameters we highlight the significance of heterogeneous intercellular interactions on tumor progression. Within this paper we present the implementation of the Cellular Potts Model graphically presented through Cytoscape.js within a Web application. The tool is available under the MIT license at https://github.com/davcem/cpm-cytoscape and http://styx.cgv.tugraz.at:8080/cpm-cytoscape/ . In-silico methods overcome the lack of wet experimental possibilities and as dry method succeed in terms of reduction, refinement and replacement of animal experimentation, also known as the 3R principles. Our visualization approach to simulation allows for more flexible usage and easy extension to facilitate understanding and gain novel insight. We believe that biomedical research in general and research on tumor growth in particular will benefit from the systems biology perspective.

  6. In vitro and in vivo tumor models for studies of distribution of radiolabelled monoclonal antibodies and fragments

    International Nuclear Information System (INIS)

    Buchegger, F.; Halpern, S.E.; Sutherland, R.M.; Schreyer, M.; Mach, J.P.; Rochester Univ., NY

    1986-01-01

    Colon carcinoma multicellular spheroids were incubated in vitro with radiolabelled MAbs. The more rapid penetration of fragments as compared to intact MAbs was clearly demonstrated. For the study of antibody localization in tumors in vivo, the model of nude mice with ligated kidneys was used. Although very artificial, this model allowed to demonstrate that, without urinary excretion, Fab fragments accumulated more rapidly into the tumor than intact MAbs and disappeared faster from the blood. This difference was less striking for F(ab') 2 fragments. In the liver a decreased accumulation of both types of fragments as compared to intact MAbs was observed. Concerning radio-immunotherapy we think that Fab fragments are not useful because of their too short half-life the circulation and in tumor and because they will probably be too toxic for the kidneys. Intact MAbs and F(ab') 2 fragments have each their advantages. Intact MAbs show highest tumor accumulation in mice without ligated kidney, however, they remain mostly on the periphery of tumor nodules, as shown by autoradiography. F(ab') 2 fragments have been found to penetrate deeper into the tumor and to accumulate less in the liver. It might be therefore an advantage to combine intact MAbs with F(ab') 2 fragments, so that in the tumor two different regions could be attacked whereas in normal tissues toxicity could be distributed to different organs such as to the liver with intact MAbs and to the kidney with F(ab') 2 fragments. (orig.) [de

  7. A novel BLK-induced tumor model

    DEFF Research Database (Denmark)

    Petersen, David Leander; Berthelsen, Jens; Willerslev-Olsen, Andreas

    2017-01-01

    -hematological malignancies including breast, kidney, and lung cancers, suggesting that BLK could be a new potential target for therapy. Here, we studied the oncogenic potential of human BLK. We found that engrafted Ba/F3 cells stably expressing constitutive active human BLK formed tumors in mice, whereas neither Ba/F3 cells...... expressing wild type BLK nor non-transfected Ba/F3 cells did. Inhibition of BLK with the clinical grade and broadly reacting SRC family kinase inhibitor dasatinib inhibited growth of BLK-induced tumors. In conclusion, our study provides evidence that human BLK is a true proto-oncogene capable of inducing...... tumors, and we demonstrate a novel BLK activity-dependent tumor model suitable for studies of BLK-driven lymphomagenesis and screening of novel BLK inhibitors in vivo....

  8. Model of vascular desmoplastic multispecies tumor growth.

    Science.gov (United States)

    Ng, Chin F; Frieboes, Hermann B

    2017-10-07

    We present a three-dimensional nonlinear tumor growth model composed of heterogeneous cell types in a multicomponent-multispecies system, including viable, dead, healthy host, and extra-cellular matrix (ECM) tissue species. The model includes the capability for abnormal ECM dynamics noted in tumor development, as exemplified by pancreatic ductal adenocarcinoma, including dense desmoplasia typically characterized by a significant increase of interstitial connective tissue. An elastic energy is implemented to provide elasticity to the connective tissue. Cancer-associated fibroblasts (myofibroblasts) are modeled as key contributors to this ECM remodeling. The tumor growth is driven by growth factors released by these stromal cells as well as by oxygen and glucose provided by blood vasculature which along with lymphatics are stimulated to proliferate in and around the tumor based on pro-angiogenic factors released by hypoxic tissue regions. Cellular metabolic processes are simulated, including respiration and glycolysis with lactate fermentation. The bicarbonate buffering system is included for cellular pH regulation. This model system may be of use to simulate the complex interactions between tumor and stromal cells as well as the associated ECM and vascular remodeling that typically characterize malignant cancers notorious for poor therapeutic response. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Augmented reality in a tumor resection model.

    Science.gov (United States)

    Chauvet, Pauline; Collins, Toby; Debize, Clement; Novais-Gameiro, Lorraine; Pereira, Bruno; Bartoli, Adrien; Canis, Michel; Bourdel, Nicolas

    2018-03-01

    Augmented Reality (AR) guidance is a technology that allows a surgeon to see sub-surface structures, by overlaying pre-operative imaging data on a live laparoscopic video. Our objectives were to evaluate a state-of-the-art AR guidance system in a tumor surgical resection model, comparing the accuracy of the resection with and without the system. Our system has three phases. Phase 1: using the MRI images, the kidney's and pseudotumor's surfaces are segmented to construct a 3D model. Phase 2: the intra-operative 3D model of the kidney is computed. Phase 3: the pre-operative and intra-operative models are registered, and the laparoscopic view is augmented with the pre-operative data. We performed a prospective experimental study on ex vivo porcine kidneys. Alginate was injected into the parenchyma to create pseudotumors measuring 4-10 mm. The kidneys were then analyzed by MRI. Next, the kidneys were placed into pelvictrainers, and the pseudotumors were laparoscopically resected. The AR guidance system allows the surgeon to see tumors and margins using classical laparoscopic instruments, and a classical screen. The resection margins were measured microscopically to evaluate the accuracy of resection. Ninety tumors were segmented: 28 were used to optimize the AR software, and 62 were used to randomly compare surgical resection: 29 tumors were resected using AR and 33 without AR. The analysis of our pathological results showed 4 failures (tumor with positive margins) (13.8%) in the AR group, and 10 (30.3%) in the Non-AR group. There was no complete miss in the AR group, while there were 4 complete misses in the non-AR group. In total, 14 (42.4%) tumors were completely missed or had a positive margin in the non-AR group. Our AR system enhances the accuracy of surgical resection, particularly for small tumors. Crucial information such as resection margins and vascularization could also be displayed.

  10. Modeling tumor invasion and metastasis in Drosophila

    Directory of Open Access Journals (Sweden)

    Wayne O. Miles

    2011-11-01

    Full Text Available Conservation of major signaling pathways between humans and flies has made Drosophila a useful model organism for cancer research. Our understanding of the mechanisms regulating cell growth, differentiation and development has been considerably advanced by studies in Drosophila. Several recent high profile studies have examined the processes constraining the metastatic growth of tumor cells in fruit fly models. Cell invasion can be studied in the context of an in vivo setting in flies, enabling the genetic requirements of the microenvironment of tumor cells undergoing metastasis to be analyzed. This Perspective discusses the strengths and limitations of Drosophila models of cancer invasion and the unique tools that have enabled these studies. It also highlights several recent reports that together make a strong case for Drosophila as a system with the potential for both testing novel concepts in tumor progression and cell invasion, and for uncovering players in metastasis.

  11. Spheroid droplets evaporation of water solutions

    Directory of Open Access Journals (Sweden)

    Misyura S.Y.

    2017-01-01

    Full Text Available Droplet film boiling on a horizontal heating surface was studied experimentally. The heat transfer coefficient of droplet water solution in the spheroidal state decreases with a rise of wall overheating and spheroid diameter. Evaporation of small spheroid (diameter d 20 mm. At the evaporation of large spheroids a spheroid shape changes in time that significantly affect coefficients of generalizing curves that use dimensionless numbers.

  12. Sarcoma Spheroids and Organoids—Promising Tools in the Era of Personalized Medicine

    Directory of Open Access Journals (Sweden)

    Gianluca Colella

    2018-02-01

    Full Text Available Cancer treatment is rapidly evolving toward personalized medicine, which takes into account the individual molecular and genetic variability of tumors. Sophisticated new in vitro disease models, such as three-dimensional cell cultures, may provide a tool for genetic, epigenetic, biomedical, and pharmacological research, and help determine the most promising individual treatment. Sarcomas, malignant neoplasms originating from mesenchymal cells, may have a multitude of genomic aberrations that give rise to more than 70 different histopathological subtypes. Their low incidence and high level of histopathological heterogeneity have greatly limited progress in their treatment, and trials of clinical sarcoma are less frequent than trials of other carcinomas. The main advantage of 3D cultures from tumor cells or biopsy is that they provide patient-specific models of solid tumors, and they overcome some limitations of traditional 2D monolayer cultures by reflecting cell heterogeneity, native histologic architectures, and cell–extracellular matrix interactions. Recent advances promise that these models can help bridge the gap between preclinical and clinical research by providing a relevant in vitro model of human cancer useful for drug testing and studying metastatic and dormancy mechanisms. However, additional improvements of 3D models are expected in the future, specifically the inclusion of tumor vasculature and the immune system, to enhance their full ability to capture the biological features of native tumors in high-throughput screening. Here, we summarize recent advances and future perspectives of spheroid and organoid in vitro models of rare sarcomas that can be used to investigate individual molecular biology and predict clinical responses. We also highlight how spheroid and organoid culture models could facilitate the personalization of sarcoma treatment, provide specific clinical scenarios, and discuss the relative strengths and limitations

  13. Reovirus FAST Protein Enhances Vesicular Stomatitis Virus Oncolytic Virotherapy in Primary and Metastatic Tumor Models

    Directory of Open Access Journals (Sweden)

    Fabrice Le Boeuf

    2017-09-01

    Full Text Available The reovirus fusion-associated small transmembrane (FAST proteins are the smallest known viral fusogens (∼100–150 amino acids and efficiently induce cell-cell fusion and syncytium formation in multiple cell types. Syncytium formation enhances cell-cell virus transmission and may also induce immunogenic cell death, a form of apoptosis that stimulates immune recognition of tumor cells. These properties suggest that FAST proteins might serve to enhance oncolytic virotherapy. The oncolytic activity of recombinant VSVΔM51 (an interferon-sensitive vesicular stomatitis virus [VSV] mutant encoding the p14 FAST protein (VSV-p14 was compared with a similar construct encoding GFP (VSV-GFP in cell culture and syngeneic BALB/c tumor models. Compared with VSV-GFP, VSV-p14 exhibited increased oncolytic activity against MCF-7 and 4T1 breast cancer spheroids in culture and reduced primary 4T1 breast tumor growth in vivo. VSV-p14 prolonged survival in both primary and metastatic 4T1 breast cancer models, and in a CT26 metastatic colon cancer model. As with VSV-GFP, VSV-p14 preferentially replicated in vivo in tumors and was cleared rapidly from other sites. Furthermore, VSV-p14 increased the numbers of activated splenic CD4, CD8, natural killer (NK, and natural killer T (NKT cells, and increased the number of activated CD4 and CD8 cells in tumors. FAST proteins may therefore provide a multi-pronged approach to improving oncolytic virotherapy via syncytium formation and enhanced immune stimulation.

  14. Datamining approaches for modeling tumor control probability.

    Science.gov (United States)

    Naqa, Issam El; Deasy, Joseph O; Mu, Yi; Huang, Ellen; Hope, Andrew J; Lindsay, Patricia E; Apte, Aditya; Alaly, James; Bradley, Jeffrey D

    2010-11-01

    Tumor control probability (TCP) to radiotherapy is determined by complex interactions between tumor biology, tumor microenvironment, radiation dosimetry, and patient-related variables. The complexity of these heterogeneous variable interactions constitutes a challenge for building predictive models for routine clinical practice. We describe a datamining framework that can unravel the higher order relationships among dosimetric dose-volume prognostic variables, interrogate various radiobiological processes, and generalize to unseen data before when applied prospectively. Several datamining approaches are discussed that include dose-volume metrics, equivalent uniform dose, mechanistic Poisson model, and model building methods using statistical regression and machine learning techniques. Institutional datasets of non-small cell lung cancer (NSCLC) patients are used to demonstrate these methods. The performance of the different methods was evaluated using bivariate Spearman rank correlations (rs). Over-fitting was controlled via resampling methods. Using a dataset of 56 patients with primary NCSLC tumors and 23 candidate variables, we estimated GTV volume and V75 to be the best model parameters for predicting TCP using statistical resampling and a logistic model. Using these variables, the support vector machine (SVM) kernel method provided superior performance for TCP prediction with an rs=0.68 on leave-one-out testing compared to logistic regression (rs=0.4), Poisson-based TCP (rs=0.33), and cell kill equivalent uniform dose model (rs=0.17). The prediction of treatment response can be improved by utilizing datamining approaches, which are able to unravel important non-linear complex interactions among model variables and have the capacity to predict on unseen data for prospective clinical applications.

  15. A new ODE tumor growth modeling based on tumor population dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Oroji, Amin; Omar, Mohd bin [Institute of Mathematical Sciences, Faculty of Science University of Malaya, 50603 Kuala Lumpur, Malaysia amin.oroji@siswa.um.edu.my, mohd@um.edu.my (Malaysia); Yarahmadian, Shantia [Mathematics Department Mississippi State University, USA Syarahmadian@math.msstate.edu (United States)

    2015-10-22

    In this paper a new mathematical model for the population of tumor growth treated by radiation is proposed. The cells dynamics population in each state and the dynamics of whole tumor population are studied. Furthermore, a new definition of tumor lifespan is presented. Finally, the effects of two main parameters, treatment parameter (q), and repair mechanism parameter (r) on tumor lifespan are probed, and it is showed that the change in treatment parameter (q) highly affects the tumor lifespan.

  16. A new ODE tumor growth modeling based on tumor population dynamics

    International Nuclear Information System (INIS)

    Oroji, Amin; Omar, Mohd bin; Yarahmadian, Shantia

    2015-01-01

    In this paper a new mathematical model for the population of tumor growth treated by radiation is proposed. The cells dynamics population in each state and the dynamics of whole tumor population are studied. Furthermore, a new definition of tumor lifespan is presented. Finally, the effects of two main parameters, treatment parameter (q), and repair mechanism parameter (r) on tumor lifespan are probed, and it is showed that the change in treatment parameter (q) highly affects the tumor lifespan

  17. Human tumor infiltrating lymphocytes cooperatively regulate prostate tumor growth in a humanized mouse model

    OpenAIRE

    Roth, Michael D; Harui, Airi

    2015-01-01

    BACKGROUND: The complex interactions that occur between human tumors, tumor infiltrating lymphocytes (TIL) and the systemic immune system are likely to define critical factors in the host response to cancer. While conventional animal models have identified an array of potential anti-tumor therapies, mouse models often fail to translate into effective human treatments. Our goal is to establish a humanized tumor model as a more effective pre-clinical platform for understanding and manipulating ...

  18. Modeling measurement error in tumor characterization studies

    Directory of Open Access Journals (Sweden)

    Marjoram Paul

    2011-07-01

    Full Text Available Abstract Background Etiologic studies of cancer increasingly use molecular features such as gene expression, DNA methylation and sequence mutation to subclassify the cancer type. In large population-based studies, the tumor tissues available for study are archival specimens that provide variable amounts of amplifiable DNA for molecular analysis. As molecular features measured from small amounts of tumor DNA are inherently noisy, we propose a novel approach to improve statistical efficiency when comparing groups of samples. We illustrate the phenomenon using the MethyLight technology, applying our proposed analysis to compare MLH1 DNA methylation levels in males and females studied in the Colon Cancer Family Registry. Results We introduce two methods for computing empirical weights to model heteroscedasticity that is caused by sampling variable quantities of DNA for molecular analysis. In a simulation study, we show that using these weights in a linear regression model is more powerful for identifying differentially methylated loci than standard regression analysis. The increase in power depends on the underlying relationship between variation in outcome measure and input DNA quantity in the study samples. Conclusions Tumor characteristics measured from small amounts of tumor DNA are inherently noisy. We propose a statistical analysis that accounts for the measurement error due to sampling variation of the molecular feature and show how it can improve the power to detect differential characteristics between patient groups.

  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. The liquid overlay technique is the key to formation of co-culture spheroids consisting of primary osteoblasts, fibroblasts and endothelial cells.

    Science.gov (United States)

    Metzger, Wolfgang; Sossong, Daniela; Bächle, Annick; Pütz, Norbert; Wennemuth, Gunther; Pohlemann, Tim; Oberringer, Martin

    2011-09-01

    The 3-dimensional (3-D) culture of various cell types reflects the in vivo situation more precisely than 2-dimensional (2-D) cell culture techniques. Spheroids as 3-D cell constructs have been used in tumor research for a long time. They have also been used to study angiogenic mechanisms, which are essential for the success of many tissue-engineering approaches. Several methods of forming spheroids are known, but there is a lack of systematic studies evaluating the performance of these techniques. We evaluated the performance of the hanging drop technique, carboxymethyl cellulose technique and liquid overlay technique to form both mono- and co-culture spheroids consisting of primary osteoblasts, fibroblasts and endothelial cells. The performance of the three techniques was evaluated in terms of rate of yield and reproducibility. The size of the generated spheroids was determined systematically. The liquid overlay technique was the most suitable for generating spheroids reproducibly. The rate of yield for this technique was between 60% and 100% for monoculture spheroids and 100% for co-culture spheroids. The size of the spheroids could be adjusted easily and precisely by varying the number of seeded cells organized in one spheroid. The formation of co-culture spheroids consisting of three different cell types was possible. Our results show that the most suitable technique for forming spheroids can vary from the chosen cell type, especially if primary cells are used. Co-culture spheroids consisting of three different cell types will be used to study angiogenic phenomena in further studies.

  1. SIZE AND SHAPE FACTOR EXTREMES OF SPHEROIDS

    Directory of Open Access Journals (Sweden)

    Daniel Hlubinka

    2011-05-01

    Full Text Available In the paper we consider random prolate (oblate spheroids and their random profiles. The limiting distribution of the extremal characteristics of the spheroids is related to the limiting distribution of the corresponding extremal characteristics of the profiles. The difference between the analysis of the prolate and oblate spheroids is discussed. We propose the possible application of the theoretical results.

  2. Bistable flows in precessing spheroids

    Energy Technology Data Exchange (ETDEWEB)

    Cébron, D, E-mail: david.cebron@ujf-grenoble.fr [Université Grenoble Alpes, CNRS, ISTerre, Grenoble (France)

    2015-04-15

    Precession driven flows are found in any rotating container filled with liquid, when the rotation axis itself rotates about a secondary axis that is fixed in an inertial frame of reference. Because of its relevance for planetary fluid layers, many works consider spheroidal containers, where the uniform vorticity component of the bulk flow is reliably given by the well-known equations obtained by Busse (1968 J. Fluid Mech. 33 739–51). So far however, no analytical result for the solutions is available. Moreover, the cases where multiple flows can coexist have not been investigated in detail since their discovery by Noir et al (2003 Geophys. J. Int. 154 407–16). In this work we aim at deriving analytical results for the solutions, aiming in particular at first estimating the ranges of parameters where multiple solutions exist, and second studying quantitatively their stability. Using the models recently proposed by Noir and Cébron (2013 J. Fluid Mech. 737 412–39), which are more generic in the inviscid limit than the equations of Busse, we analytically describe these solutions, their conditions of existence, and their stability in a systematic manner. We then successfully compare these analytical results with the theory of Busse (1968). Dynamical model equations are finally proposed to investigate the stability of the solutions, which describe the bifurcation of the unstable flow solution. We also report for the first time the possibility that time-dependent multiple flows can coexist in precessing triaxial ellipsoids. Numerical integrations of the algebraic and differential equations have been efficiently performed with the dedicated script FLIPPER (supplementary material). (paper)

  3. Manganese in dwarf spheroidal galaxies

    Science.gov (United States)

    North, P.; Cescutti, G.; Jablonka, P.; Hill, V.; Shetrone, M.; Letarte, B.; Lemasle, B.; Venn, K. A.; Battaglia, G.; Tolstoy, E.; Irwin, M. J.; Primas, F.; François, P.

    2012-05-01

    We provide manganese abundances (corrected for the effect of the hyperfine structure) for a large number of stars in the dwarf spheroidal galaxies Sculptor and Fornax, and for a smaller number in the Carina and Sextans dSph galaxies. Abundances had already been determined for a number of other elements in these galaxies, including α and iron-peak ones, which allowed us to build [Mn/Fe] and [Mn/α] versus [Fe/H] diagrams. The Mn abundances imply sub-solar [Mn/Fe] ratios for the stars in all four galaxies examined. In Sculptor, [Mn/Fe] stays roughly constant between [Fe/H] ~ -1.8 and -1.4 and decreases at higher iron abundance. In Fornax, [Mn/Fe] does not vary in any significant way with [Fe/H]. The relation between [Mn/α] and [Fe/H] for the dSph galaxies is clearly systematically offset from that for the Milky Way, which reflects the different star formation histories of the respective galaxies. The [Mn/α] behavior can be interpreted as a result of the metal-dependent Mn yields of Type II and Type Ia supernovae. We also computed chemical evolution models for star formation histories matching those determined empirically for Sculptor, Fornax, and Carina, and for the Mn yields of SNe Ia, which were assumed to be either constant or variable with metallicity. The observed [Mn/Fe] versus [Fe/H] relation in Sculptor, Fornax, and Carina can be reproduced only by the chemical evolution models that include a metallicity-dependent Mn yield from the SNe Ia. Based on observations made with the FLAMES-GIRAFFE multi-object spectrograph mounted on the Kuyen VLT telescope at ESO-Paranal Observatory (programs 171.B-0588, 074.B-0415 and 076.B-0146).Appendices are available in electronic form at http://www.aanda.org

  4. Spheroid culture as a tool for creating 3D complex tissues

    NARCIS (Netherlands)

    Fennema, E.M.; Rivron, N.C.; Rouwkema, Jeroen; van Blitterswijk, Clemens; de Boer, Jan

    2013-01-01

    3D cell culture methods confer a high degree of clinical and biological relevance to in vitro models. This is specifically the case with the spheroid culture, where a small aggregate of cells grows free of foreign materials. In spheroid cultures, cells secrete the extracellular matrix (ECM) in which

  5. Brain Tumor Segmentation Using a Generative Model with an RBM Prior on Tumor Shape

    DEFF Research Database (Denmark)

    Agn, Mikael; Puonti, Oula; Rosenschöld, Per Munck af

    2016-01-01

    In this paper, we present a fully automated generative method for brain tumor segmentation in multi-modal magnetic resonance images. The method is based on the type of generative model often used for segmenting healthy brain tissues, where tissues are modeled by Gaussian mixture models combined...... with a spatial atlas-based tissue prior. We extend this basic model with a tumor prior, which uses convolutional restricted Boltzmann machines (cRBMs) to model the shape of both tumor core and complete tumor, which includes edema and core. The cRBMs are trained on expert segmentations of training images, without...

  6. 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...

  7. Three-Dimensional Patient-Derived In Vitro Sarcoma Models: Promising Tools for Improving Clinical Tumor Management

    Directory of Open Access Journals (Sweden)

    Manuela Gaebler

    2017-09-01

    Full Text Available Over the past decade, the development of new targeted therapeutics directed against specific molecular pathways involved in tumor cell proliferation and survival has allowed an essential improvement in carcinoma treatment. Unfortunately, the scenario is different for sarcomas, a group of malignant neoplasms originating from mesenchymal cells, for which the main therapeutic approach still consists in the combination of surgery, chemotherapy, and radiation therapy. The lack of innovative approaches in sarcoma treatment stems from the high degree of heterogeneity of this tumor type, with more that 70 different histopathological subtypes, and the limited knowledge of the molecular drivers of tumor development and progression. Currently, molecular therapies are available mainly for the treatment of gastrointestinal stromal tumor, a soft-tissue malignancy characterized by an activating mutation of the tyrosine kinase KIT. Since the first application of this approach, a strong effort has been made to understand sarcoma molecular alterations that can be potential targets for therapy. The low incidence combined with the high level of histopathological heterogeneity makes the development of clinical trials for sarcomas very challenging. For this reason, preclinical studies are needed to better understand tumor biology with the aim to develop new targeted therapeutics. Currently, these studies are mainly based on in vitro testing, since cell lines, and in particular patient-derived models, represent a reliable and easy to handle tool for investigation. In the present review, we summarize the most important models currently available in the field, focusing in particular on the three-dimensional spheroid/organoid model. This innovative approach for studying tumor biology better represents tissue architecture and cell–cell as well as cell–microenvironment crosstalk, which are fundamental steps for tumor cell proliferation and survival.

  8. Global Landslides on Rapidly Spinning Spheroids

    Science.gov (United States)

    Scheeres, Daniel J.; Sanchez, P.

    2013-10-01

    The angle of repose and conditions for global landslides on the surfaces of small, rapidly spinning, spheroidal asteroids are studied. Applying techniques of soil mechanics, we develop a theory for, and examples of, how regolith will fail and flow in this microgravity environment. Our motivation is to develop an understanding of the "top-shaped" class of asteroids based on analytical soil mechanics. Our analysis transforms the entire asteroid surface into a local frame where we can model it as a conventional granular pile with a surface slope, acceleration and height variations as a function of the body's spin rate, shape and density. A general finding is that the lowest point on a rapidly spinning spheroid is at the equator with the effective height of surface material monotonically increasing towards the polar regions, where the height can be larger than the physical radius of the body. We study the failure conditions of both cohesionless and cohesive regolith, and develop specific predictions of the surface profile as a function of the regolith angle of friction and the maximum spin rate experienced by the body. The theory also provides simple guidelines on what the shape may look like, although we do not analyze gravitationally self-consistent evolution of the body shape. The theory is tested with soft-sphere discrete element method granular mechanics simulations to better understand the dynamical aspects of global asteroid landslides. We find significant differences between failure conditions for cohesive and cohesionless regolith. In the case of cohesive regolith, we show that extremely small values of strength (much less than that found in lunar regolith) can stabilize a surface even at very rapid spin rates. Cohesionless surfaces, as expected, fail whenever their surface slopes exceed the angle of friction. Based on our analysis we propose that global landslides and the flow of material towards the equator on spheroidal bodies are precipitated by exogenous

  9. Spheroidal Integral Equations for Geodetic Inversion of Geopotential Gradients

    Science.gov (United States)

    Novák, Pavel; Šprlák, Michal

    2017-12-01

    The static Earth's gravitational field has traditionally been described in geodesy and geophysics by the gravitational potential (geopotential for short), a scalar function of 3-D position. Although not directly observable, geopotential functionals such as its first- and second-order gradients are routinely measured by ground, airborne and/or satellite sensors. In geodesy, these observables are often used for recovery of the static geopotential at some simple reference surface approximating the actual Earth's surface. A generalized mathematical model is represented by a surface integral equation which originates in solving Dirichlet's boundary-value problem of the potential theory defined for the harmonic geopotential, spheroidal boundary and globally distributed gradient data. The mathematical model can be used for combining various geopotential gradients without necessity of their re-sampling or prior continuation in space. The model extends the apparatus of integral equations which results from solving boundary-value problems of the potential theory to all geopotential gradients observed by current ground, airborne and satellite sensors. Differences between spherical and spheroidal formulations of integral kernel functions of Green's kind are investigated. Estimated differences reach relative values at the level of 3% which demonstrates the significance of spheroidal approximation for flattened bodies such as the Earth. The observation model can be used for combined inversion of currently available geopotential gradients while exploring their spectral and stochastic characteristics. The model would be even more relevant to gravitational field modelling of other bodies in space with more pronounced spheroidal geometry than that of the Earth.

  10. Spheroidal Integral Equations for Geodetic Inversion of Geopotential Gradients

    Science.gov (United States)

    Novák, Pavel; Šprlák, Michal

    2018-03-01

    The static Earth's gravitational field has traditionally been described in geodesy and geophysics by the gravitational potential (geopotential for short), a scalar function of 3-D position. Although not directly observable, geopotential functionals such as its first- and second-order gradients are routinely measured by ground, airborne and/or satellite sensors. In geodesy, these observables are often used for recovery of the static geopotential at some simple reference surface approximating the actual Earth's surface. A generalized mathematical model is represented by a surface integral equation which originates in solving Dirichlet's boundary-value problem of the potential theory defined for the harmonic geopotential, spheroidal boundary and globally distributed gradient data. The mathematical model can be used for combining various geopotential gradients without necessity of their re-sampling or prior continuation in space. The model extends the apparatus of integral equations which results from solving boundary-value problems of the potential theory to all geopotential gradients observed by current ground, airborne and satellite sensors. Differences between spherical and spheroidal formulations of integral kernel functions of Green's kind are investigated. Estimated differences reach relative values at the level of 3% which demonstrates the significance of spheroidal approximation for flattened bodies such as the Earth. The observation model can be used for combined inversion of currently available geopotential gradients while exploring their spectral and stochastic characteristics. The model would be even more relevant to gravitational field modelling of other bodies in space with more pronounced spheroidal geometry than that of the Earth.

  11. Cyclophosphamide Enhances Human Tumor Growth in Nude Rat Xenografted Tumor Models

    Directory of Open Access Journals (Sweden)

    Yingjen Jeffrey Wu

    2009-02-01

    Full Text Available The effect of the immunomodulatory chemotherapeutic agent cyclophosphamide (CTX on tumor growth was investigated in primary and metastatic intracerebral and subcutaneous rat xenograft models. Nude rats were treated with CTX (100 mg/kg, intraperitoneally 24 hours before human ovarian carcinoma (SKOV3, small cell lung carcinoma (LX-1 SCLC, and glioma (UW28, U87MG, and U251 tumor cells were inoculated subcutaneously, intraperitoneally, or in the right cerebral hemisphere or were infused into the right internal carotid artery. Tumor development was monitored and recorded. Potential mechanisms were further investigated. Only animals that received both CTX and Matrigel showed consistent growth of subcutaneous tumors. Cyclophosphamide pretreatment increased the percentage (83.3% vs 0% of animals showing intraperitoneal tumors. In intracerebral implantation tumor models, CTX pretreatment increased the tumor volume and the percentage of animals showing tumors. Cyclophosphamide increased lung carcinoma bone and facial metastases after intra-arterial injection, and 20% of animals showed brain metastases. Cyclophosphamide transiently decreased nude rat white blood cell counts and glutathione concentration, whereas serum vascular endothelial growth factor was significantly elevated. Cyclophosphamide also increased CD31 reactivity, a marker of vascular endothelium, and macrophage (CD68-positive infiltration into glioma cell-inoculated rat brains. Cyclophosphamide may enhance primary and metastatic tumor growth through multiple mechanisms, including immune modulation, decreased response to oxidative stress, increased tumor vascularization, and increased macrophage infiltration. These findings may be clinically relevant because chemotherapy may predispose human cancer subjects to tumor growth in the brain or other tissues.

  12. Electron spin resonance microscopic imaging of oxygen concentration in cancer spheroids

    Science.gov (United States)

    Hashem, Mada; Weiler-Sagie, Michal; Kuppusamy, Periannan; Neufeld, Gera; Neeman, Michal; Blank, Aharon

    2015-07-01

    Oxygen (O2) plays a central role in most living organisms. The concentration of O2 is important in physiology and pathology. Despite the importance of accurate knowledge of the O2 levels, there is very limited capability to measure with high spatial resolution its distribution in millimeter-scale live biological samples. Many of the current oximetric methods, such as oxygen microelectrodes and fluorescence lifetime imaging, are compromised by O2 consumption, sample destruction, invasiveness, and difficulty to calibrate. Here, we present a new method, based on the use of the pulsed electron spin resonance (ESR) microimaging technique to obtain a 3D mapping of oxygen concentration in millimeter-scale biological samples. ESR imaging requires the incorporation of a suitable stable and inert paramagnetic spin probe into the desirable object. In this work, we use microcrystals of a paramagnetic spin probe in a new crystallographic packing form (denoted tg-LiNc-BuO). These paramagnetic species interact with paramagnetic oxygen molecules, causing a spectral line broadening that is linearly proportional to the oxygen concentration. Typical ESR results include 4D spatial-spectral images that give an indication about the oxygen concentration in different regions of the sample. This new oximetry microimaging method addresses all the problems mentioned above. It is noninvasive, sensitive to physiological oxygen levels, and easy to calibrate. Furthermore, in principle, it can be used for repetitive measurements without causing cell damage. The tissue model used in this research is spheroids of Human Colorectal carcinoma cell line (HCT-116) with a typical diameter of ∼600 μm. Most studies of the microenvironmental O2 conditions inside such viable spheroids carried out in the past used microelectrodes, which require an invasive puncturing of the spheroid and are also not applicable to 3D O2 imaging. High resolution 3D oxygen maps could make it possible to evaluate the

  13. A theoretical study of the spheroidal droplet evaporation in forced convection

    International Nuclear Information System (INIS)

    Li, Jie; Zhang, Jian

    2014-01-01

    In many applications, the shape of a droplet may be assumed to be an oblate spheroid. A theoretical study is conducted on the evaporation of an oblate spheroidal droplet under forced convection conditions. Closed-form analytical expressions of the mass evaporation rate for an oblate spheroid are derived, in the regime of controlled mass-transfer and heat-transfer, respectively. The variation of droplet size during the evaporation process is presented in the regime of shrinking dynamic model. Comparing with the droplets having the same surface area, an increase in the aspect ratio enhances the mass evaporation rate and prolongs the burnout time. - Highlights: • Fully algebraic solutions for the spheroidal droplet evaporation rate is obtained. • We examine the effect of aspect ratio on the droplet evaporation. • We propose a calculation method of Nusselt number for spheroidal droplet

  14. High-Throughput Spheroid Screens Using Volume, Resazurin Reduction, and Acid Phosphatase Activity.

    Science.gov (United States)

    Ivanov, Delyan P; Grabowska, Anna M; Garnett, Martin C

    2017-01-01

    Mainstream adoption of physiologically relevant three-dimensional models has been slow in the last 50 years due to long, manual protocols with poor reproducibility, high price, and closed commercial platforms. This chapter describes high-throughput, low-cost, open methods for spheroid viability assessment which use readily available reagents and open-source software to analyze spheroid volume, metabolism, and enzymatic activity. We provide two ImageJ macros for automated spheroid size determination-for both single images and images in stacks. We also share an Excel template spreadsheet allowing users to rapidly process spheroid size data, analyze plate uniformity (such as edge effects and systematic seeding errors), detect outliers, and calculate dose-response. The methods would be useful to researchers in preclinical and translational research planning to move away from simplistic monolayer studies and explore 3D spheroid screens for drug safety and efficacy without substantial investment in money or time.

  15. Mathematical models of tumor growth: translating absorbed dose to tumor control probability

    International Nuclear Information System (INIS)

    Sgouros, G.

    1996-01-01

    Full text: The dose-rate in internal emitter therapy is low and time-dependent as compared to external beam radiotherapy. Once the total absorbed dose delivered to a target tissue is calculated, however, most dosimetric analyses of radiopharmaceuticals are considered complete. To translate absorbed dose estimates obtained for internal emitter therapy to biologic effect, the growth characteristics, repair capacity, and radiosensitivity of the tumor must be considered. Tumor growth may be represented by the Gompertz equation in which tumor cells increase at an exponential growth rate that is itself decreasing at an exponential rate; as the tumor increases in size, the growth rate diminishes. The empirical Gompertz expression for tumor growth may be derived from a mechanistic model in which growth is represented by a balance between tumor-cell birth and loss. The birth rate is assumed to be fixed, while the cell loss rate is time-dependent and increases with tumor size. The birth rate of the tumors may be related to their potential doubling time. Multiple biopsies of individual tumors have demonstrated a heterogeneity in the potential doubling time of tumors. By extending the mechanistic model described above to allow for sub-populations of tumor cells with different birth rates, the effect of kinetic heterogeneity within a tumor may be examined. Model simulations demonstrate that the cell kinetic parameters of a tumor are predicted to change over time and measurements obtained using a biopsy are unlikely to reflect the kinetics of the tumor throughout its growth history. A decrease in overall tumor mass, in which each sub-population is reduced in proportion to its cell number, i.e., the log-kill assumption, leads to re-growth of a tumor that has a greater proliferation rate. Therapy that is linked to the potential doubling time or to the effective proliferation rate of the tumor may lead to re-growth of a tumor that is kinetically unchanged. The simplest model of

  16. Charged fluid distribution in higher dimensional spheroidal space-time

    Indian Academy of Sciences (India)

    analogue of Tolman's solutions. Recently, Ponce de Leon and Cruz [11] have con- sidered higher dimensional Schwarzschild space-time and studied the influence of the extra dimensions on the equilibrium configuration of stars. Vaidya and Tikekar. [12] have discussed spheroidal space-time and obtained an exact model ...

  17. Therapeutic Implications from Sensitivity Analysis of Tumor Angiogenesis Models

    Science.gov (United States)

    Poleszczuk, Jan; Hahnfeldt, Philip; Enderling, Heiko

    2015-01-01

    Anti-angiogenic cancer treatments induce tumor starvation and regression by targeting the tumor vasculature that delivers oxygen and nutrients. Mathematical models prove valuable tools to study the proof-of-concept, efficacy and underlying mechanisms of such treatment approaches. The effects of parameter value uncertainties for two models of tumor development under angiogenic signaling and anti-angiogenic treatment are studied. Data fitting is performed to compare predictions of both models and to obtain nominal parameter values for sensitivity analysis. Sensitivity analysis reveals that the success of different cancer treatments depends on tumor size and tumor intrinsic parameters. In particular, we show that tumors with ample vascular support can be successfully targeted with conventional cytotoxic treatments. On the other hand, tumors with curtailed vascular support are not limited by their growth rate and therefore interruption of neovascularization emerges as the most promising treatment target. PMID:25785600

  18. Scalable robotic biofabrication of tissue spheroids

    Energy Technology Data Exchange (ETDEWEB)

    Mehesz, A Nagy; Hajdu, Z; Visconti, R P; Markwald, R R; Mironov, V [Advanced Tissue Biofabrication Center, Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC (United States); Brown, J [Department of Mechanical Engineering, Clemson University, Clemson, SC (United States); Beaver, W [York Technical College, Rock Hill, SC (United States); Da Silva, J V L, E-mail: mironovv@musc.edu [Renato Archer Information Technology Center-CTI, Campinas (Brazil)

    2011-06-15

    Development of methods for scalable biofabrication of uniformly sized tissue spheroids is essential for tissue spheroid-based bioprinting of large size tissue and organ constructs. The most recent scalable technique for tissue spheroid fabrication employs a micromolded recessed template prepared in a non-adhesive hydrogel, wherein the cells loaded into the template self-assemble into tissue spheroids due to gravitational force. In this study, we present an improved version of this technique. A new mold was designed to enable generation of 61 microrecessions in each well of a 96-well plate. The microrecessions were seeded with cells using an EpMotion 5070 automated pipetting machine. After 48 h of incubation, tissue spheroids formed at the bottom of each microrecession. To assess the quality of constructs generated using this technology, 600 tissue spheroids made by this method were compared with 600 spheroids generated by the conventional hanging drop method. These analyses showed that tissue spheroids fabricated by the micromolded method are more uniform in diameter. Thus, use of micromolded recessions in a non-adhesive hydrogel, combined with automated cell seeding, is a reliable method for scalable robotic fabrication of uniform-sized tissue spheroids.

  19. Dynamical analysis of fractional order model of immunogenic tumors

    Directory of Open Access Journals (Sweden)

    Sadia Arshad

    2016-07-01

    Full Text Available In this article, we examine the fractional order model of the cytotoxic T lymphocyte response to a growing tumor cell population. We investigate the long-term behavior of tumor growth and explore the conditions of tumor elimination analytically. We establish the conditions for the tumor-free equilibrium and tumor-infection equilibrium to be asymptotically stable and provide the expression of the basic reproduction number. Existence of physical significant tumor-infection equilibrium points is investigated analytically. We show that tumor growth rate, source rate of immune cells, and death rate of immune cells play vital role in tumor dynamics and system undergoes saddle-node and transcritical bifurcation based on these parameters. Furthermore, the effect of cancer treatment is discussed by varying the values of relevant parameters. Numerical simulations are presented to illustrate the analytical results.

  20. Canine parvovirus NS1 protein exhibits anti-tumor activity in a mouse mammary tumor model.

    Science.gov (United States)

    Gupta, Shishir Kumar; Yadav, Pavan Kumar; Gandham, Ravi Kumar; Sahoo, A P; Harish, D R; Singh, Arvind Kumar; Tiwari, A K

    2016-02-02

    Many viral proteins have the ability to kill tumor cells specifically without harming the normal cells. These proteins, on ectopic expression, cause lysis or induction of apoptosis in the target tumor cells. Parvovirus NS1 is one of such proteins, which is known to kill high proliferating tumor cells. In the present study, we assessed the apoptosis inducing ability of canine parvovirus type 2 NS1 protein (CPV2.NS1) in vitro in 4T1 cells, and found it to cause significant cell death due to induction of apoptosis through intrinsic or mitochondrial pathway. Further, we also evaluated the oncolytic activity of CPV2.NS1 protein in a mouse mammary tumor model. The results suggested that CPV2.NS1 was able to inhibit the growth of 4T1 induced mouse mammary tumor as indicated by significantly reduced tumor volume, mitotic, AgNOR and PCNA indices. Further, inhibition of tumor growth was found to be because of induction of apoptosis in the tumor cells, which was evident by a significant increase in the number of TUNEL positive cells. Further, CPV2.NS1 was also able to stimulate the immune cells against the tumor antigens as indicated by the increased CD4+ and CD8+ counts in the blood of CVP2.NS1 treated mice. Further optimization of the delivery of NS1 protein and use of an adjuvant may further enhance its anti-tumor activity. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Computational modeling of brain tumors: discrete, continuum or hybrid?

    Science.gov (United States)

    Wang, Zhihui; Deisboeck, Thomas S.

    In spite of all efforts, patients diagnosed with highly malignant brain tumors (gliomas), continue to face a grim prognosis. Achieving significant therapeutic advances will also require a more detailed quantitative understanding of the dynamic interactions among tumor cells, and between these cells and their biological microenvironment. Data-driven computational brain tumor models have the potential to provide experimental tumor biologists with such quantitative and cost-efficient tools to generate and test hypotheses on tumor progression, and to infer fundamental operating principles governing bidirectional signal propagation in multicellular cancer systems. This review highlights the modeling objectives of and challenges with developing such in silico brain tumor models by outlining two distinct computational approaches: discrete and continuum, each with representative examples. Future directions of this integrative computational neuro-oncology field, such as hybrid multiscale multiresolution modeling are discussed.

  2. A tumor cord model for Doxorubicin delivery and dose optimization in solid tumors

    Directory of Open Access Journals (Sweden)

    Eikenberry Steffen

    2009-08-01

    Full Text Available Abstract Background Doxorubicin is a common anticancer agent used in the treatment of a number of neoplasms, with the lifetime dose limited due to the potential for cardiotoxocity. This has motivated efforts to develop optimal dosage regimes that maximize anti-tumor activity while minimizing cardiac toxicity, which is correlated with peak plasma concentration. Doxorubicin is characterized by poor penetration from tumoral vessels into the tumor mass, due to the highly irregular tumor vasculature. I model the delivery of a soluble drug from the vasculature to a solid tumor using a tumor cord model and examine the penetration of doxorubicin under different dosage regimes and tumor microenvironments. Methods A coupled ODE-PDE model is employed where drug is transported from the vasculature into a tumor cord domain according to the principle of solute transport. Within the tumor cord, extracellular drug diffuses and saturable pharmacokinetics govern uptake and efflux by cancer cells. Cancer cell death is also determined as a function of peak intracellular drug concentration. Results The model predicts that transport to the tumor cord from the vasculature is dominated by diffusive transport of free drug during the initial plasma drug distribution phase. I characterize the effect of all parameters describing the tumor microenvironment on drug delivery, and large intercapillary distance is predicted to be a major barrier to drug delivery. Comparing continuous drug infusion with bolus injection shows that the optimum infusion time depends upon the drug dose, with bolus injection best for low-dose therapy but short infusions better for high doses. Simulations of multiple treatments suggest that additional treatments have similar efficacy in terms of cell mortality, but drug penetration is limited. Moreover, fractionating a single large dose into several smaller doses slightly improves anti-tumor efficacy. Conclusion Drug infusion time has a significant

  3. Characterization of variants isolated from BCNU-treated 9L multicellular spheroids

    International Nuclear Information System (INIS)

    Hoff, M.H.B.; Deen, D.F.

    1984-01-01

    Multicellular spheroids of the 9L rat brain tumor cell line were treated with a single high-dose to produce cells of varying sensitivity. Treatment of 350-450 μm diameter 9L spheroids with 45 μM BCNU for 1 hr at 37 0 C produced 5 log cell kill. Some of the treated spheroids were dissociated immediately after treatment; others were dissociated after 1 wk. From these populations, twenty clones were selected and passaged as monolayers. Each clone was assayed at passage 2 for BCNU-induced damage using colony forming efficiency and sister chromatid exchange. 60% of the clones were resistant to BCNU, 15% were unchanged, and 15% appeared hypersensitive as compared with the control, which were uncloned 9L cells. All of the hypersensitive clones originated from the spheroids that remained in suspension after treatment. Three clones were studied during subsequent passage in monolayer. Two resistant clones maintained their resistance to BCNU over -- 25 passages, while one hypersensitive clone appeared to become progressively more resistant during passage. Thus, as with monolayer and in vivo 9L cells, a single high-dose treatment with BCNU produces a spectrum of sensitivities to BCNU. Some of these phenotypes are stable over many passages and have been used to initiate 9L spheroids having varying sensitivity to BCNU. These spheroids will be used to investigate drug-radiation interactions

  4. Modelling Nanoparticle Diffusion into Cancer Tumors

    Science.gov (United States)

    Podduturi, Vishwa Priya; Derosa, Pedro

    2011-03-01

    Cancer is one of the major, potentially deadly diseases and has been for years. Non-specific delivery of the drug can damage healthy tissue seriously affecting in many cases the patient's living condition. Nanoparticles are being used for a targeted drug delivery thereby reducing the dose. In addition, metallic nanoparticles are being used in thermal treatment of cancer cells where nanoparticles help concentrate heat in the tumor and away from living tissue. We proposed a model that combines random walk with diffusion principles. The particle drift velocity is taken from the Hagen-Poiseuille equation and the velocity profile of the particle at the pores in the capillary wall is obtained using the Coventorware software. Pressure gradient and concentration gradient through the capillary wall are considered. Simulations are performed in Matlab using the Monte Carlo technique. Number of particles leaving the blood vessel through a pore is obtained as a function of blood pressure, the osmotic pressure, temperature, particle concentration, blood vessel radius, and pore size, and the relative effect of each of the parameters is discussed.

  5. Modeling and testing treated tumor growth using cubic smoothing splines.

    Science.gov (United States)

    Kong, Maiying; Yan, Jun

    2011-07-01

    Human tumor xenograft models are often used in preclinical study to evaluate the therapeutic efficacy of a certain compound or a combination of certain compounds. In a typical human tumor xenograft model, human carcinoma cells are implanted to subjects such as severe combined immunodeficient (SCID) mice. Treatment with test compounds is initiated after tumor nodule has appeared, and continued for a certain time period. Tumor volumes are measured over the duration of the experiment. It is well known that untreated tumor growth may follow certain patterns, which can be described by certain mathematical models. However, the growth patterns of the treated tumors with multiple treatment episodes are quite complex, and the usage of parametric models is limited. We propose using cubic smoothing splines to describe tumor growth for each treatment group and for each subject, respectively. The proposed smoothing splines are quite flexible in modeling different growth patterns. In addition, using this procedure, we can obtain tumor growth and growth rate over time for each treatment group and for each subject, and examine whether tumor growth follows certain growth pattern. To examine the overall treatment effect and group differences, the scaled chi-squared test statistics based on the fitted group-level growth curves are proposed. A case study is provided to illustrate the application of this method, and simulations are carried out to examine the performances of the scaled chi-squared tests. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Radioresistance of human glioma spheroids and expression of HSP70, p53 and EGFr

    International Nuclear Information System (INIS)

    Fedrigo, Carlos A; Rocha, Adriana B da; Grivicich, Ivana; Schunemann, Daniel P; Chemale, Ivan M; Santos, Daiane dos; Jacovas, Thais; Boschetti, Patryck S; Jotz, Geraldo P; Filho, Aroldo Braga

    2011-01-01

    Radiation therapy is routinely prescribed for high-grade malignant gliomas. However, the efficacy of this therapeutic modality is often limited by the occurrence of radioresistance, reflected as a diminished susceptibility of the irradiated cells to undergo cell death. Thus, cells have evolved an elegant system in response to ionizing radiation induced DNA damage, where p53, Hsp70 and/or EGFr may play an important role in the process. In the present study, we investigated whether the content of p53, Hsp70 and EGFr are associated to glioblastoma (GBM) cell radioresistance. Spheroids from U-87MG and MO59J cell lines as well as spheroids derived from primary culture of tumor tissue of one GBM patient (UGBM1) were irradiated (5, 10 and 20 Gy), their relative radioresistance were established and the p53, Hsp70 and EGFr contents were immunohistochemically determined. Moreover, we investigated whether EGFr-phospho-Akt and EGFr-MEK-ERK pathways can induce GBM radioresistance using inhibitors of activation of ERK (PD098059) and Akt (wortmannin). At 5 Gy irradiation UGBM1 and U-87MG spheroids showed growth inhibition whereas the MO59J spheroid was relatively radioresistant. Overall, no significant changes in p53 and Hsp70 expression were found following 5 Gy irradiation treatment in all spheroids studied. The only difference observed in Hsp70 content was the periphery distribution in MO59J spheroids. However, 5 Gy treatment induced a significant increase on the EGFr levels in MO59J spheroids. Furthermore, treatment with inhibitors of activation of ERK (PD098059) and Akt (wortmannin) leads to radiosensitization of MO59J spheroids. These results indicate that the PI3K-Akt and MEK-ERK pathways triggered by EGFr confer GBM radioresistance

  7. Model construction of nursing service satisfaction in hospitalized tumor patients.

    Science.gov (United States)

    Chen, Yongyi; Liu, Jingshi; Xiao, Shuiyuan; Liu, Xiangyu; Tang, Xinhui; Zhou, Yujuan

    2014-01-01

    This study aims to construct a satisfaction model on nursing service in hospitalized tumor patients. Using questionnaires, data about hospitalized tumor patients' expectation, quality perception and satisfaction of hospital nursing service were obtained. A satisfaction model of nursing service in hospitalized tumor patients was established through empirical study and by structural equation method. This model was suitable for tumor specialized hospital, with reliability and validity. Patient satisfaction was significantly affected by quality perception and patient expectation. Patient satisfaction and patient loyalty was also affected by disease pressure. Hospital brand was positively correlated with patient satisfaction and patient loyalty, negatively correlated with patient complaint. Patient satisfaction was positively correlated with patient loyalty, patient complaints, and quality perception, and negatively correlated with disease pressure and patient expectation. The satisfaction model on nursing service in hospitalized tumor patients fits well. By this model, the quality of hospital nursing care may be improved.

  8. Patient-specific three-dimensional explant spheroids derived from human nasal airway epithelium

    DEFF Research Database (Denmark)

    Marthin, June Kehlet; Stevens, Elizabeth Munkebjerg; Larsen, Lars Allan

    2017-01-01

    BACKGROUND: Three-dimensional explant spheroid formation is an ex vivo technique previously used in studies of airway epithelial ion and water transport. Explanted cells and sheets of nasal epithelium form fully differentiated spheroids enclosing a partly fluid-filled lumen with the ciliated apical...... in a single healthy person. CONCLUSION: Patient-specific three-dimensional explant spheroid formation from a minimal invasive nasal brush biopsy is a feasible, fast and valid ex vivo method to assess ciliary function with potential of aiding the diagnosis of PCD. In addition, it may be a useful model...

  9. Single and 30 fraction tumor control doses correlate in xenografted tumor models: implications for predictive assays

    International Nuclear Information System (INIS)

    Gerweck, Leo E.; Dubois, Willum; Baumann, Michael; Suit, Herman D.

    1995-01-01

    , the rank-order correlation coefficient between the single dose hypoxic versus fractionated dose TCD50s under hypoxic or aerobic conditions was 1.0. For all 5 tumors examined, a trend for rank correlation was observed between the single dose and the fractionated dose TCD50s performed under normal or clamp hypoxic conditions (r=0.7, p=0.16 in both cases). The linear correlation coefficients were 0.83, p=0.08 and 0.72, p=0.17, respectively. Failure to attain a rank correlation of 1.0 was due to one tumor exhibiting an insignificant fractionation effect. The rank correlation between the TCD50s for fractionated treatments under normal versus the extrapolated TCD50s under clamp hypoxic conditions was 1.00; the linear correlation coefficient was 0.97 (p=0.01). Conclusions: In the tumor models examined, factors controlling the single fraction tumor control dose, also impact the response to fractionated treatments. These results suggest that laboratory estimates of intrinsic radiosensitivity and tumor clonogen number at the onset of treatment, will be of use in predicting radiocurability for fractionated treatments, as has been observed for single dose treatments

  10. Heralding a new paradigm in 3D tumor modeling.

    Science.gov (United States)

    Fong, Eliza L S; Harrington, Daniel A; Farach-Carson, Mary C; Yu, Hanry

    2016-11-01

    Numerous studies to date have contributed to a paradigm shift in modeling cancer, moving from the traditional two-dimensional culture system to three-dimensional (3D) culture systems for cancer cell culture. This led to the inception of tumor engineering, which has undergone rapid advances over the years. In line with the recognition that tumors are not merely masses of proliferating cancer cells but rather, highly complex tissues consisting of a dynamic extracellular matrix together with stromal, immune and endothelial cells, significant efforts have been made to better recapitulate the tumor microenvironment in 3D. These approaches include the development of engineered matrices and co-cultures to replicate the complexity of tumor-stroma interactions in vitro. However, the tumor engineering and cancer biology fields have traditionally relied heavily on the use of cancer cell lines as a cell source in tumor modeling. While cancer cell lines have contributed to a wealth of knowledge in cancer biology, the use of this cell source is increasingly perceived as a major contributing factor to the dismal failure rate of oncology drugs in drug development. Backing this notion is the increasing evidence that tumors possess intrinsic heterogeneity, which predominantly homogeneous cancer cell lines poorly reflect. Tumor heterogeneity contributes to therapeutic resistance in patients. To overcome this limitation, cancer cell lines are beginning to be replaced by primary tumor cell sources, in the form of patient-derived xenografts and organoids cultures. Moving forward, we propose that further advances in tumor engineering would require that tumor heterogeneity (tumor variants) be taken into consideration together with tumor complexity (tumor-stroma interactions). In this review, we provide a comprehensive overview of what has been achieved in recapitulating tumor complexity, and discuss the importance of incorporating tumor heterogeneity into 3D in vitro tumor models. This

  11. Tumor bioengineering using a transglutaminase crosslinked hydrogel.

    Directory of Open Access Journals (Sweden)

    Josephine Y Fang

    Full Text Available Development of a physiologically relevant 3D model system for cancer research and drug development is a current challenge. We have adopted a 3D culture system based on a transglutaminase-crosslinked gelatin gel (Col-Tgel to mimic the tumor 3D microenvironment. The system has several unique advantages over other alternatives including presenting cell-matrix interaction sites from collagen-derived peptides, geometry-initiated multicellular tumor spheroids, and metabolic gradients in the tumor microenvironment. Also it provides a controllable wide spectrum of gel stiffness for mechanical signals, and technical compatibility with imaging based screening due to its transparent properties. In addition, the Col-Tgel provides a cure-in-situ delivery vehicle for tumor xenograft formation in animals enhancing tumor cell uptake rate. Overall, this distinctive 3D system could offer a platform to more accurately mimic in vivo situations to study tumor formation and progression both in vitro and in vivo.

  12. A model of tumor architecture and spatial interactions with tumor microenvironment in breast carcinoma

    Science.gov (United States)

    Ben Cheikh, Bassem; Bor-Angelier, Catherine; Racoceanu, Daniel

    2017-03-01

    Breast carcinomas are cancers that arise from the epithelial cells of the breast, which are the cells that line the lobules and the lactiferous ducts. Breast carcinoma is the most common type of breast cancer and can be divided into different subtypes based on architectural features and growth patterns, recognized during a histopathological examination. Tumor microenvironment (TME) is the cellular environment in which tumor cells develop. Being composed of various cell types having different biological roles, TME is recognized as playing an important role in the progression of the disease. The architectural heterogeneity in breast carcinomas and the spatial interactions with TME are, to date, not well understood. Developing a spatial model of tumor architecture and spatial interactions with TME can advance our understanding of tumor heterogeneity. Furthermore, generating histological synthetic datasets can contribute to validating, and comparing analytical methods that are used in digital pathology. In this work, we propose a modeling method that applies to different breast carcinoma subtypes and TME spatial distributions based on mathematical morphology. The model is based on a few morphological parameters that give access to a large spectrum of breast tumor architectures and are able to differentiate in-situ ductal carcinomas (DCIS) and histological subtypes of invasive carcinomas such as ductal (IDC) and lobular carcinoma (ILC). In addition, a part of the parameters of the model controls the spatial distribution of TME relative to the tumor. The validation of the model has been performed by comparing morphological features between real and simulated images.

  13. A Big Bang model of human colorectal tumor growth.

    Science.gov (United States)

    Sottoriva, Andrea; Kang, Haeyoun; Ma, Zhicheng; Graham, Trevor A; Salomon, Matthew P; Zhao, Junsong; Marjoram, Paul; Siegmund, Kimberly; Press, Michael F; Shibata, Darryl; Curtis, Christina

    2015-03-01

    What happens in early, still undetectable human malignancies is unknown because direct observations are impractical. Here we present and validate a 'Big Bang' model, whereby tumors grow predominantly as a single expansion producing numerous intermixed subclones that are not subject to stringent selection and where both public (clonal) and most detectable private (subclonal) alterations arise early during growth. Genomic profiling of 349 individual glands from 15 colorectal tumors showed an absence of selective sweeps, uniformly high intratumoral heterogeneity (ITH) and subclone mixing in distant regions, as postulated by our model. We also verified the prediction that most detectable ITH originates from early private alterations and not from later clonal expansions, thus exposing the profile of the primordial tumor. Moreover, some tumors appear 'born to be bad', with subclone mixing indicative of early malignant potential. This new model provides a quantitative framework to interpret tumor growth dynamics and the origins of ITH, with important clinical implications.

  14. Numerical modeling of fluid flow in solid tumors.

    Directory of Open Access Journals (Sweden)

    M Soltani

    Full Text Available A mathematical model of interstitial fluid flow is developed, based on the application of the governing equations for fluid flow, i.e., the conservation laws for mass and momentum, to physiological systems containing solid tumors. The discretized form of the governing equations, with appropriate boundary conditions, is developed for a predefined tumor geometry. The interstitial fluid pressure and velocity are calculated using a numerical method, element based finite volume. Simulations of interstitial fluid transport in a homogeneous solid tumor demonstrate that, in a uniformly perfused tumor, i.e., one with no necrotic region, because of the interstitial pressure distribution, the distribution of drug particles is non-uniform. Pressure distribution for different values of necrotic radii is examined and two new parameters, the critical tumor radius and critical necrotic radius, are defined. Simulation results show that: 1 tumor radii have a critical size. Below this size, the maximum interstitial fluid pressure is less than what is generally considered to be effective pressure (a parameter determined by vascular pressure, plasma osmotic pressure, and interstitial osmotic pressure. Above this size, the maximum interstitial fluid pressure is equal to effective pressure. As a consequence, drugs transport to the center of smaller tumors is much easier than transport to the center of a tumor whose radius is greater than the critical tumor radius; 2 there is a critical necrotic radius, below which the interstitial fluid pressure at the tumor center is at its maximum value. If the tumor radius is greater than the critical tumor radius, this maximum pressure is equal to effective pressure. Above this critical necrotic radius, the interstitial fluid pressure at the tumor center is below effective pressure. In specific ranges of these critical sizes, drug amount and therefore therapeutic effects are higher because the opposing force, interstitial fluid

  15. A novel lab-on-a-chip platform for spheroid metabolism monitoring.

    Science.gov (United States)

    Alexander, Frank; Eggert, Sebastian; Wiest, Joachim

    2018-02-01

    Sensor-based cellular microphysiometry is a technique that allows non-invasive, label-free, real-time monitoring of living cells that can greatly improve the predictability of toxicology testing by removing the influence of biochemical labels. In this work, the Intelligent Mobile Lab for In Vitro Diagnostics (IMOLA-IVD) was utilized to perform cellular microphysiometry on 3D multicellular spheroids. Using a commercial 3D printer, 3 × 3 microwell arrays were fabricated to maintain nine previously cultured HepG2 spheroids on a single BioChip. Integrated layers above and under the spheroids allowed fluidic contact between spheroids in microwells and BioChip sensors while preventing wash out from medium perfusion. Spheroid culturing protocols were optimized to grow spheroids to a diameter of around 620 μm prior to transfer onto BioChips. An ON/OFF pump cycling protocol was developed to optimize spheroid culture within the designed microwells, intermittently perfuse spheroids with fresh culture medium, and measure the extracellular acidification rate (EAR) and oxygen uptake rate (OUR) with the BioChips of the IMOLA-IVD platform. In a proof-of-concept experiment, spheroids were perfused for 36 h with cell culture medium before being exposed to medium with 1% sodium dodecyl sulphate (SDS) to lyse cells as a positive control. These microphysiometry studies revealed a repeatable pattern of extracellular acidification throughout the experiment, indicating the ability to monitor real-time metabolic activity of spheroids embedded in the newly designed tissue encapsulation. After perfusion for 36 h with medium, SDS exposure resulted in an instant decrease in EAR and OUR signals from 37 mV/h (± 5) to 8 mV/h (± 8) and from 308 mV/h (± 21) to -2 mV/h (± 13), respectively. The presented spheroid monitoring system holds great potential as a method to automate screening and analysis of pharmaceutical agents using 3D multicellular spheroid models.

  16. Human tumor infiltrating lymphocytes cooperatively regulate prostate tumor growth in a humanized mouse model.

    Science.gov (United States)

    Roth, Michael D; Harui, Airi

    2015-01-01

    The complex interactions that occur between human tumors, tumor infiltrating lymphocytes (TIL) and the systemic immune system are likely to define critical factors in the host response to cancer. While conventional animal models have identified an array of potential anti-tumor therapies, mouse models often fail to translate into effective human treatments. Our goal is to establish a humanized tumor model as a more effective pre-clinical platform for understanding and manipulating TIL. The immune system in NOD/SCID/IL-2Rγnull (NSG) mice was reconstituted by the co-administration of human peripheral blood lymphocytes (PBL) or subsets (CD4+ or CD8+) and autologous human dendritic cells (DC), and animals simultaneously challenged by implanting human prostate cancer cells (PC3 line). Tumor growth was evaluated over time and the phenotype of recovered splenocytes and TIL characterized by flow cytometry and immunohistochemistry (IHC). Serum levels of circulating cytokines and chemokines were also assessed. A tumor-bearing huPBL-NSG model was established in which human leukocytes reconstituted secondary lymphoid organs and promoted the accumulation of TIL. These TIL exhibited a unique phenotype when compared to splenocytes with a predominance of CD8+ T cells that exhibited increased expression of CD69, CD56, and an effector memory phenotype. TIL from huPBL-NSG animals closely matched the features of TIL recovered from primary human prostate cancers. Human cytokines were readily detectible in the serum and exhibited a different profile in animals implanted with PBL alone, tumor alone, and those reconstituted with both. Immune reconstitution slowed but could not eliminate tumor growth and this effect required the presence of CD4+ T cell help. Simultaneous implantation of human PBL, DC and tumor results in a huPBL-NSG model that recapitulates the development of human TIL and allows an assessment of tumor and immune system interaction that cannot be carried out in humans

  17. Direct Measurements of Oxygen Gradients in Spheroid Culture System Using Electron Parametric Resonance Oximetry.

    Directory of Open Access Journals (Sweden)

    Laura M Langan

    Full Text Available Advanced in vitro culture from tissues of different origin includes three-dimensional (3D organoid micro structures that may mimic conditions in vivo. One example of simple 3D culture is spheroids; ball shaped structures typically used as liver and tumour models. Oxygen is critically important in physiological processes, but is difficult to quantify in 3D culture: and the question arises, how small does a spheroid have to be to have minimal micro-environment formation? This question is of particular importance in the growing field of 3D based models for toxicological assessment. Here, we describe a simple non-invasive approach modified for the quantitative measurement and subsequent evaluation of oxygen gradients in spheroids developed from a non-malignant fish cell line (i.e. RTG-2 cells using Electron Paramagnetic Resonance (EPR oximetry. Sonication of the paramagnetic probe Lithium phthalocyanine (LiPc allows for incorporation of probe particulates into spheroid during its formation. Spectra signal strength after incorporation of probe into spheroid indicated that a volume of 20 μl of probe (stock solution: 0.10 mg/mL is sufficient to provide a strong spectra across a range of spheroid sizes. The addition of non-toxic probes (that do not produce or consume oxygen report on oxygen diffusion throughout the spheroid as a function of size. We provide evidence supporting the use of this model over a range of initial cell seeding densities and spheroid sizes with the production of oxygen distribution as a function of these parameters. In our spheroid model, lower cell seeding densities (∼2,500 cells/spheroid and absolute size (118±32 μm allow control of factors such as pre-existing stresses (e.g. ∼ 2% normoxic/hypoxic interface for more accurate measurement of treatment response. The applied methodology provides an elegant, widely applicable approach to directly characterize spheroid (and other organoid cultures in biomedical and

  18. Characterization of genetic intratumor heterogeneity in colorectal cancer and matching patient-derived spheroid cultures

    DEFF Research Database (Denmark)

    Árnadóttir, Sigrid S; Jeppesen, Maria; Lamy, Philippe

    2018-01-01

    Patient-derived in vitro cultures of colorectal cancer (CRC) may help guide treatment strategies prior to patient treatment. However, most previous studies have been performed on a single biopsy per tumor. The purpose of this study was to analyze multiple spatially distinct biopsies from CRCs...... and spheroids contained private mutations. Therefore, multiple cultures from spatially distinct sites of the tumor increase the insight into the genetic profile of the entire tumor. Molecular subtypes were called from RNA sequencing data. When based on transcripts from both cancer and noncancerous cells......, the subtypes were largely independent of sampling site. In contrast, subtyping based on cancer cell transcripts alone was dependent on sample site and genetic ITH. In conclusion, all examined CRC tumors showed genetic ITH. Spheroid cultures partly reflected this ITH, and having multiple cultures from distinct...

  19. Advances in the formation, use and understanding of multi-cellular spheroids.

    Science.gov (United States)

    Achilli, Toni-Marie; Meyer, Julia; Morgan, Jeffrey R

    2012-10-01

    Developing in vitro models for studying cell biology and cell physiology is of great importance to the fields of biotechnology, cancer research, drug discovery, toxicity testing, as well as the emerging fields of tissue engineering and regenerative medicine. Traditional two-dimensional (2D) methods of mammalian cell culture have several limitations and it is increasingly recognized that cells grown in a three-dimensional (3D) environment more closely represent normal cellular function due to the increased cell-to-cell interactions, and by mimicking the in vivo architecture of natural organs and tissues. In this review, we discuss the methods to form 3D multi-cellular spheroids, the advantages and limitations of these methods, and assays used to characterize the function of spheroids. The use of spheroids has led to many advances in basic cell sciences, including understanding cancer cell interactions, creating models for drug discovery and cancer metastasis, and they are being investigated as basic units for engineering tissue constructs. As so, this review will focus on contributions made to each of these fields using spheroid models. Multi-cellular spheroids are rich in biological content and mimic better the in vivo environment than 2D cell culture. New technologies to form and analyze spheroids are rapidly increasing their adoption and expanding their applications.

  20. Cyclosporin safety in a simplified rat brain tumor implantation model

    Directory of Open Access Journals (Sweden)

    Francisco H. C. Felix

    2012-01-01

    Full Text Available Brain cancer is the second neurological cause of death. A simplified animal brain tumor model using W256 (carcinoma 256, Walker cell line was developed to permit the testing of novel treatment modalities. Wistar rats had a cell tumor solution inoculated stereotactically in the basal ganglia (right subfrontal caudate. This model yielded tumor growth in 95% of the animals, and showed absence of extracranial metastasis and systemic infection. Survival median was 10 days. Estimated tumor volume was 17.08±6.7 mm³ on the 7th day and 67.25±19.8 mm³ on 9th day post-inoculation. Doubling time was 24.25 h. Tumor growth induced cachexia, but no hematological or biochemical alterations. This model behaved as an undifferentiated tumor and can be promising for studying tumor cell migration in the central nervous system. Dexamethasone 3.0 mg/kg/day diminished significantly survival in this model. Cyclosporine 10 mg/kg/day administration was safely tolerated.

  1. Modeling the Effect of Tumor Size in Early Breast Cancer

    Science.gov (United States)

    Verschraegen, Claire; Vinh-Hung, Vincent; Cserni, Gábor; Gordon, Richard; Royce, Melanie E.; Vlastos, Georges; Tai, Patricia; Storme, Guy

    2005-01-01

    Summary Background Data: The purpose of this study was to determine the type of relationship between tumor size and mortality in early breast carcinoma. Methods: The data was abstracted from 83,686 cases registered in the Surveillance, Epidemiology, and End Results Program of women diagnosed with primary breast carcinoma between 1988 and 1997 presenting with a T1–T2 lesion and no metastasis in whom axillary node dissection was performed: 58,070 women were node-negative (N0) and 25,616 were node-positive (N+). End point was death from any cause. Tumor size was modeled as a continuous variable by proportional hazards using a generalized additive models procedure. Results: Functionally, a Gompertzian expression exp(-exp(-(size-15)/10)) provided a good fit to the effect of tumor size (in millimeters) on mortality, irrespective of nodal status. Quantitatively, for tumor size between 3 and 50 mm, the increase of crude cumulative death rate (number of observed deaths divided by the number of patients at risk) increased with size from 10% to 25% for N0 and from 20% to 40% for N+. Conclusions: The functional relationship of tumor size with mortality is concordant with current knowledge of tumor growth. However, its qualitative and quantitative independence of nodal status is in contradiction with the prevailing concept of sequential disease progression from primary tumor to regional nodes. This argues against the perception that nodal metastases are caused by the primary tumor. PMID:15650642

  2. Anti-tumor immunity generated by photodynamic therapy in a metastatic murine tumor model

    Science.gov (United States)

    Castano, Ana P.; Hamblin, Michael R.

    2005-04-01

    Photodynamic therapy (PDT) is a modality for the treatment of cancer involving excitation of photosensitizers with harmless visible light producing reactive oxygen species. The major biological effects of PDT are apoptosis of tumor cells, destruction of the blood supply and activation of the immune system. The objective of this study is to compare in an animal model of metastatic cancer, PDT alone and PDT combined with low-dose cyclophosphamide (CY). Since the tumor we used is highly metastatic, it is necessary to generate anti-tumor immunity using PDT to both cure the primary tumor and prevent death from metastasis. This immunity may be potentiated by low dose CY. In our model we used J774 cells (a Balb/c reticulum cell sarcoma line with the characteristics of macrophages) and the following PDT regimen: benzoporphyrin derivative monoacid ring A (BPD, 2mg/kg injected IV followed after 15 min by 150 J/cm2 of 690-nm light). CY (50 mg/kg i.p.) was injected 48 hours before light delivery. BPD-PDT led to complete regression of the primary tumor in more than half the mice but no permanent cures were obtained. BPD-PDT in combination with CY led to 60% permanent cures. CY alone gave no permanent cures but did provide a survival advantage. To probe permanent immunity cured animals were rechallenged with the same tumor cell line and the tumors were rejected in 71% of mice cured with BPD-PDT plus CY. We conclude that BPD-PDT in combination with CY gives best overall results and that this is attributable to immunological response activation in addition to PDT-mediated destruction of the tumor.

  3. Mathematical Modeling of Branching Morphogenesis and Vascular Tumor Growth

    Science.gov (United States)

    Yan, Huaming

    Feedback regulation of cell lineages is known to play an important role in tissue size control, but the effect in tissue morphogenesis has yet to be explored. We first use a non-spatial model to show that a combination of positive and negative feedback on stem and/or progenitor cell self-renewal leads to bistable or bi-modal growth behaviors and ultrasensitivity to external growth cues. Next, a spatiotemporal model is used to demonstrate spatial patterns such as local budding and branching arise in this setting, and are not consequences of Turing-type instabilities. We next extend the model to a three-dimensional hybrid discrete-continuum model of tumor growth to study the effects of angiogenesis, tumor progression and cancer therapies. We account for the crosstalk between the vasculature and cancer stem cells (CSCs), and CSC transdifferentiation into vascular endothelial cells (gECs), as observed experimentally. The vasculature stabilizes tumor invasiveness but considerably enhances growth. A gEC network structure forms spontaneously within the hypoxic core, consistent with experimental findings. The model is then used to study cancer therapeutics. We demonstrate that traditional anti-angiogenic therapies decelerate tumor growth, but make the tumor highly invasive. Chemotherapies help to reduce tumor sizes, but cannot control the invasion. Anti-CSC therapies that promote differentiation or disturb the stem cell niche effectively reduce tumor invasiveness. However, gECs inherit mutations present in CSCs and are resistant to traditional therapies. We show that anti-gEC treatments block the support on CSCs by gECs, and reduce both tumor size and invasiveness. Our study suggests that therapies targeting the vasculature, CSCs and gECs, when combined, are highly synergistic and are capable of controlling both tumor size and shape.

  4. Modeling and Targeting MYC Genes in Childhood Brain Tumors

    Science.gov (United States)

    Hutter, Sonja; Bolin, Sara; Weishaupt, Holger; Swartling, Fredrik J.

    2017-01-01

    Brain tumors are the second most common group of childhood cancers, accounting for about 20%–25% of all pediatric tumors. Deregulated expression of the MYC family of transcription factors, particularly c-MYC and MYCN genes, has been found in many of these neoplasms, and their expression levels are often correlated with poor prognosis. Elevated c-MYC/MYCN initiates and drives tumorigenesis in many in vivo model systems of pediatric brain tumors. Therefore, inhibition of their oncogenic function is an attractive therapeutic target. In this review, we explore the roles of MYC oncoproteins and their molecular targets during the formation, maintenance, and recurrence of childhood brain tumors. We also briefly summarize recent progress in the development of therapeutic approaches for pharmacological inhibition of MYC activity in these tumors. PMID:28333115

  5. Mathematical and Computational Modeling for Tumor Virotherapy with Mediated Immunity.

    Science.gov (United States)

    Timalsina, Asim; Tian, Jianjun Paul; Wang, Jin

    2017-08-01

    We propose a new mathematical modeling framework based on partial differential equations to study tumor virotherapy with mediated immunity. The model incorporates both innate and adaptive immune responses and represents the complex interaction among tumor cells, oncolytic viruses, and immune systems on a domain with a moving boundary. Using carefully designed computational methods, we conduct extensive numerical simulation to the model. The results allow us to examine tumor development under a wide range of settings and provide insight into several important aspects of the virotherapy, including the dependence of the efficacy on a few key parameters and the delay in the adaptive immunity. Our findings also suggest possible ways to improve the virotherapy for tumor treatment.

  6. Computer Implementation of a New Therapeutic Model for GBM Tumor

    Directory of Open Access Journals (Sweden)

    Ali Jamali Nazari

    2014-01-01

    Full Text Available Modeling the tumor behavior in the host organ as function of time and radiation dose has been a major study in the previous decades. Here the effort in estimation of cancerous and normal cell proliferation and growth in glioblastoma multiform (GBM tumor is presented. This paper introduces a new mathematical model in the form of differential equation of tumor growth. The model contains dose delivery amount in the treatment scheme as an input term. It also can be utilized to optimize the treatment process in order to increase the patient survival period. Gene expression programming (GEP as a new concept is used for estimating this model. The LQ model has also been applied to GEP as an initial value, causing acceleration and improvement of the algorithm estimation. The model shows the number of the tumor and normal brain cells during the treatment process using the status of normal and cancerous cells in the initiation of treatment, the timing and amount of dose delivery to the patient, and a coefficient that describes the brain condition. A critical level is defined for normal cell when the patient’s death occurs. In the end the model has been verified by clinical data obtained from previous accepted formulae and some of our experimental resources. The proposed model helps to predict tumor growth during treatment process in which further treatment processes can be controlled.

  7. A fractional motion diffusion model for grading pediatric brain tumors.

    Science.gov (United States)

    Karaman, M Muge; Wang, He; Sui, Yi; Engelhard, Herbert H; Li, Yuhua; Zhou, Xiaohong Joe

    2016-01-01

    To demonstrate the feasibility of a novel fractional motion (FM) diffusion model for distinguishing low- versus high-grade pediatric brain tumors; and to investigate its possible advantage over apparent diffusion coefficient (ADC) and/or a previously reported continuous-time random-walk (CTRW) diffusion model. With approval from the institutional review board and written informed consents from the legal guardians of all participating patients, this study involved 70 children with histopathologically-proven brain tumors (30 low-grade and 40 high-grade). Multi- b -value diffusion images were acquired and analyzed using the FM, CTRW, and mono-exponential diffusion models. The FM parameters, D fm , φ , ψ (non-Gaussian diffusion statistical measures), and the CTRW parameters, D m , α , β (non-Gaussian temporal and spatial diffusion heterogeneity measures) were compared between the low- and high-grade tumor groups by using a Mann-Whitney-Wilcoxon U test. The performance of the FM model for differentiating between low- and high-grade tumors was evaluated and compared with that of the CTRW and the mono-exponential models using a receiver operating characteristic (ROC) analysis. The FM parameters were significantly lower ( p  CTRW model. Similar to the CTRW model, the FM model can improve differentiation between low- and high-grade pediatric brain tumors over ADC.

  8. Using magnetic resonance microscopy to study the growth dynamics of a glioma spheroid in collagen I: A case study

    Directory of Open Access Journals (Sweden)

    Dai Guangping

    2008-01-01

    Full Text Available Abstract Background Highly malignant gliomas are characterized by rapid growth, extensive local tissue infiltration and the resulting overall dismal clinical outcome. Gaining any additional insights into the complex interaction between this aggressive brain tumor and its microenvironment is therefore critical. Currently, the standard imaging modalities to investigate the crucial interface between tumor growth and invasion in vitro are light and confocal laser scanning microscopy. While immensely useful in cell culture, integrating these modalities with this cancer's clinical imaging method of choice, i.e. MRI, is a non-trivial endeavour. However, this integration is necessary, should advanced computational modeling be able to utilize these in vitro data to eventually predict growth behaviour in vivo. We therefore argue that employing the same imaging modality for both the experimental setting and the clinical situation it represents should have significant value from a data integration perspective. In this case study, we have investigated the feasibility of using a specific form of MRI, i.e. magnetic resonance microscopy or MRM, to study the expansion dynamics of a multicellular tumor spheroid in a collagen type I gel. Methods An U87mEGFR human giloblastoma multicellular spheroid (MTS containing approximately 4·103 cells was generated and pipetted into a collagen I gel. The sample was then imaged using a T2-weighted 3D spoiled gradient echo pulse sequence on a 14T MRI scanner over a period of 12 hours with a temporal resolution of 3 hours at room temperature. Standard histopathology was performed on the MRM sample, as well as on control samples. Results We were able to acquire three-dimensional MR images with a spatial resolution of 24 × 24 × 24 μm3. Our MRM data successfully documented the volumetric growth dynamics of an MTS in a collagen I gel over the 12-hour period. The histopathology results confirmed cell viability in the MRM sample

  9. Mouse Models Recapitulating Human Adrenocortical Tumors: What is lacking?

    Directory of Open Access Journals (Sweden)

    Felicia Leccia

    2016-07-01

    Full Text Available Adrenal cortex tumors are divided into benign forms such as primary hyperplasias and adrenocortical adenomas (ACAs, and malignant forms or adrenocortical carcinomas (ACCs. Primary hyperplasias are rare causes of ACTH-independent hypercortisolism. ACAs are the most common type of adrenal gland tumors and they are rarely functional, i.e producing steroids. When functional, adenomas result in endocrine disorders such as Cushing’s syndrome (hypercortisolism or Conn’s syndrome (hyperaldosteronism. In contrast, ACCs are extremely rare but highly aggressive tumors that may also lead to hypersecreting syndromes. Genetic analyses of patients with sporadic or familial forms of adrenocortical tumors led to the identification of potentially causative genes, most of them being involved in PKA, Wnt/β-catenin and P53 signaling pathways. Development of mouse models is a crucial step to firmly establish the functional significance of candidate genes, to dissect mechanisms leading to tumors and endocrine disorders and in fine to provide in vivo tools for therapeutic screens. In this article we will provide an overview on the existing mouse models (xenografted and genetically engineered of adrenocortical tumors by focusing on the role of PKA and Wnt/β-catenin pathways in this context. We will discuss the advantages and limitations of models that have been developed heretofore and we will point out necessary improvements in the development of next generation mouse models of adrenal diseases.

  10. International Workshop on Mathematical Modeling of Tumor-Immune Dynamics

    CERN Document Server

    Kim, Peter; Mallet, Dann

    2014-01-01

    This collection of papers offers a broad synopsis of state-of-the-art mathematical methods used in modeling the interaction between tumors and the immune system. These papers were presented at the four-day workshop on Mathematical Models of Tumor-Immune System Dynamics held in Sydney, Australia from January 7th to January 10th, 2013. The workshop brought together applied mathematicians, biologists, and clinicians actively working in the field of cancer immunology to share their current research and to increase awareness of the innovative mathematical tools that are applicable to the growing field of cancer immunology. Recent progress in cancer immunology and advances in immunotherapy suggest that the immune system plays a fundamental role in host defense against tumors and could be utilized to prevent or cure cancer. Although theoretical and experimental studies of tumor-immune system dynamics have a long history, there are still many unanswered questions about the mechanisms that govern the interaction betwe...

  11. Tumor dormancy and frailty models: A novel approach.

    Science.gov (United States)

    Rancoita, Paola M V; Valberg, Morten; Demicheli, Romano; Biganzoli, Elia; Di Serio, Clelia

    2017-03-01

    Frailty models are here proposed in the tumor dormancy framework, in order to account for possible unobservable dependence mechanisms in cancer studies where a non-negligible proportion of cancer patients relapses years or decades after surgical removal of the primary tumor. Relapses do not seem to follow a memory-less process, since their timing distribution leads to multimodal hazards. From a biomedical perspective, this behavior may be explained by tumor dormancy, i.e., for some patients microscopic tumor foci may remain asymptomatic for a prolonged time interval and, when they escape from dormancy, micrometastatic growth results in a clinical disease appearance. The activation of the growth phase at different metastatic states would explain the occurrence of metastatic recurrences and mortality at different times (multimodal hazard). We propose a new frailty model which includes in the risk function a random source of heterogeneity (frailty variable) affecting the components of the hazard function. Thus, the individual hazard rate results as the product of a random frailty variable and the sum of basic hazard rates. In tumor dormancy, the basic hazard rates correspond to micrometastatic developments starting from different initial states. The frailty variable represents the heterogeneity among patients with respect to relapse, which might be related to unknown mechanisms that regulate tumor dormancy. We use our model to estimate the overall survival in a large breast cancer dataset, showing how this improves the understanding of the underlying biological process. © 2016, The International Biometric Society.

  12. Cytoreductive Chemotherapy Improves the Biodistribution of Antibodies Directed Against Tumor Necrosis in Murine Solid Tumor Models

    Science.gov (United States)

    Jang, Julie K.; Khawli, Leslie A.; Park, Ryan; Wu, Brian W.; Li, Zibo; Canter, David; Conti, Peter S.; Epstein, Alan L.

    2013-01-01

    Current strategies in cancer treatment employ combinations of different treatment modalities, which include chemotherapy, radiotherapy, immunotherapy, and surgery. Consistent with that approach, the present study demonstrates how chemotherapeutic agents can potentiate the delivery of radiolabeled, necrosis-targeting antibodies (chTNT-3, NHS76) to tumor. All chemotherapeutics in this study (5-fluorouracil, etoposide, vinblastine, paclitaxel, and doxorubicin) resulted in statistically significant increases in tumor uptake of radiolabeled antibodies and their F(ab')2 fragments compared to no pretreatment with chemotherapy. Labeled antibodies were administered at various time points following a single dose of chemotherapy in multiple tumor models, and the biodistribution of the antibodies were determined by measuring radioactivity in harvested tissues. MicroPET/CT was also done to demonstrate clinical relevancy of using chemotherapy pretreatment to increase antibody uptake. Results of biodistribution and imaging data reveal specific time frames following chemotherapy when necrosis-targeting antibodies are best delivered, either for imaging or radiotherapy. Thus, the present work offers the prospect of using cytoreductive chemotherapy to increase tumor accumulation of select therapeutic antibodies, especially when combined with other forms of immunotherapy, for the successful treatment of solid tumors. PMID:24130055

  13. Cellular Interaction and Tumoral Penetration Properties of Cyclodextrin Nanoparticles on 3D Breast Tumor Model

    Directory of Open Access Journals (Sweden)

    Gamze Varan

    2018-01-01

    Full Text Available Amphiphilic cyclodextrins are biocompatible oligosaccharides that can be used for drug delivery especially for the delivery of drugs with solubility problems thanks to their unique molecular structures. In this paper, Paclitaxel was used as a model anticancer drug to determine the inclusion complex properties of amphiphilic cyclodextrins with different surface charge. Paclitaxel-loaded cyclodextrin nanoparticles were characterized in terms of mean particle diameter, zeta potential, encapsulation efficacy, drug release profile and cell culture studies. It was determined that the nanoparticles prepared from the inclusion complex according to characterization studies have a longer release profile than the conventionally prepared nanoparticles. In order to mimic the tumor microenvironment, breast cancer cells and healthy fibroblast cells were used in 3-dimensional (3D cell culture studies. It was determined that the activities of nanoparticles prepared by conventional methods behave differently in 2-dimensional (2D and 3D cell cultures. In addition, it was observed that the nanoparticles prepared from the inclusion complex have a stronger anti-tumoral activity in the 3D multicellular tumor model than the drug solution. Furthermore, polycationic amphiphilic cyclodextrin nanoparticles can diffuse and penetrate through multilayer cells in a 3D tumor model, which is crucial for an eventual antitumor effect.

  14. Modeling evolutionary dynamics of epigenetic mutations in hierarchically organized tumors.

    Directory of Open Access Journals (Sweden)

    Andrea Sottoriva

    2011-05-01

    Full Text Available The cancer stem cell (CSC concept is a highly debated topic in cancer research. While experimental evidence in favor of the cancer stem cell theory is apparently abundant, the results are often criticized as being difficult to interpret. An important reason for this is that most experimental data that support this model rely on transplantation studies. In this study we use a novel cellular Potts model to elucidate the dynamics of established malignancies that are driven by a small subset of CSCs. Our results demonstrate that epigenetic mutations that occur during mitosis display highly altered dynamics in CSC-driven malignancies compared to a classical, non-hierarchical model of growth. In particular, the heterogeneity observed in CSC-driven tumors is considerably higher. We speculate that this feature could be used in combination with epigenetic (methylation sequencing studies of human malignancies to prove or refute the CSC hypothesis in established tumors without the need for transplantation. Moreover our tumor growth simulations indicate that CSC-driven tumors display evolutionary features that can be considered beneficial during tumor progression. Besides an increased heterogeneity they also exhibit properties that allow the escape of clones from local fitness peaks. This leads to more aggressive phenotypes in the long run and makes the neoplasm more adaptable to stringent selective forces such as cancer treatment. Indeed when therapy is applied the clone landscape of the regrown tumor is more aggressive with respect to the primary tumor, whereas the classical model demonstrated similar patterns before and after therapy. Understanding these often counter-intuitive fundamental properties of (non-hierarchically organized malignancies is a crucial step in validating the CSC concept as well as providing insight into the therapeutical consequences of this model.

  15. Human adipose-derived mesenchymal stem cells improve motor functions and are neuroprotective in the 6-hydroxydopamine-rat model for Parkinson's disease when cultured in monolayer cultures but suppress hippocampal neurogenesis and hippocampal memory function when cultured in spheroids.

    Science.gov (United States)

    Berg, Jürgen; Roch, Manfred; Altschüler, Jennifer; Winter, Christine; Schwerk, Anne; Kurtz, Andreas; Steiner, Barbara

    2015-02-01

    Adult human adipose-derived mesenchymal stem cells (MSC) have been reported to induce neuroprotective effects in models for Parkinson's disease (PD). However, these effects strongly depend on the most optimal application of the transplant. In the present study we compared monolayer-cultured (aMSC) and spheroid (sMSC) MSC following transplantation into the substantia nigra (SN) of 6-OHDA lesioned rats regarding effects on the local microenvironment, degeneration of dopaminergic neurons, neurogenesis in the hippocampal DG as well as motor and memory function in the 6-OHDA-rat model for PD. aMSC transplantation significantly increased tyrosine hydroxylase (TH) and brain-derived neurotrophic factor (BDNF) levels in the SN, increased the levels of the glial fibrillary acidic protein (GFAP) and improved motor functions compared to untreated and sMSC treated animals. In contrast, sMSC grafting induced an increased local microgliosis, decreased TH levels in the SN and reduced numbers of newly generated cells in the dentate gyrus (DG) without yet affecting hippocampal learning and memory function. We conclude that the neuroprotective potential of adipose-derived MSC in the rat model of PD crucially depends on the applied cellular phenotype.

  16. Three-dimensional prostate tumor model based on a hyaluronic acid-alginate hydrogel for evaluation of anti-cancer drug efficacy.

    Science.gov (United States)

    Tang, Yadong; Huang, Boxin; Dong, Yuqin; Wang, Wenlong; Zheng, Xi; Zhou, Wei; Zhang, Kun; Du, Zhiyun

    2017-10-01

    In vitro cell-based assays are widely applied to evaluate anti-cancer drug efficacy. However, the conventional approaches are mostly based on two-dimensional (2D) culture systems, making it difficult to recapitulate the in vivo tumor scenario because of spatial limitations. Here, we develop an in vitro three-dimensional (3D) prostate tumor model based on a hyaluronic acid (HA)-alginate hybrid hydrogel to bridge the gap between in vitro and in vivo anticancer drug evaluations. In situ encapsulation of PCa cells was achieved by mixing HA and alginate aqueous solutions in the presence of cells and then crosslinking with calcium ions. Unlike in 2D culture, cells were found to aggregate into spheroids in a 3D matrix. The expression of epithelial to mesenchyme transition (EMT) biomarkers was found to be largely enhanced, indicating an increased invasion and metastasis potential in the hydrogel matrix. A significant up-regulation of proangiogenic growth factors (IL-8, VEGF) and matrix metalloproteinases (MMPs) was observed in 3D-cultured PCa cells. The results of anti-cancer drug evaluation suggested a higher drug tolerance within the 3D tumor model compared to conventional 2D-cultured cells. Finally, we found that the drug effect within the in vitro 3D cancer model based on HA-alginate matrix exhibited better predictability for in vivo drug efficacy.

  17. Dynamic modeling of lung tumor motion during respiration

    Energy Technology Data Exchange (ETDEWEB)

    Kyriakou, E; McKenzie, D R, E-mail: e.kyriakou@physics.usyd.edu.au, E-mail: d.mckenzie@physics.usyd.edu.au [School of Physics, University of Sydney, NSW 2006 (Australia)

    2011-05-21

    A dynamic finite element model of the lung that incorporates a simplified geometry with realistic lung material properties has been developed. Observations of lung motion from respiratory-gated computed tomography were used to provide a database against which the predictions of the model are assessed. Data from six patients presenting with lung tumors were processed to give sagittal sections of the lung containing the tumor as a function of the breathing phase. Statistical shape modeling was used to outline the diaphragm, the tumor volume and the thoracic wall at each breathing phase. The motion of the tumor in the superior-inferior direction was plotted against the diaphragm displacement. The finite element model employed a simplified geometry in which the lung material fills a rectangular volume enabling two-dimensional coordinates to be used. The diaphragm is represented as a piston, driving the motion. Plots of lung displacement against diaphragm displacement form hysteresis loops that are a sensitive indicator of the characteristics of the motion. The key parameters of lung material that determine the motion are the density and elastic properties of lung material and the airway permeability. The model predictions of the hysteresis behavior agreed well with observation only when lung material is modeled as viscoelastic. The key material parameters are suggested for use as prognostic indicators of the progression of disease and of changes arising from the response of the lung to radiation treatment.

  18. Charged fluid distribution in higher dimensional spheroidal space-time

    Indian Academy of Sciences (India)

    A general solution of Einstein field equations corresponding to a charged fluid distribution on the background of higher dimensional spheroidal space-time is obtained. The solution generates several known solutions for superdense star having spheroidal space-time geometry.

  19. Noninvasive Assessment of Tumor Cell Proliferation in Animal Models

    Directory of Open Access Journals (Sweden)

    Matthias Edinger

    1999-10-01

    Full Text Available Revealing the mechanisms of neoplastic disease and enhancing our ability to intervene in these processes requires an increased understanding of cellular and molecular changes as they occur in intact living animal models. We have begun to address these needs by developing a method of labeling tumor cells through constitutive expression of an optical reporter gene, noninvasively monitoring cellular proliferation in vivo using a sensitive photon detection system. A stable line of HeLa cells that expressed a modified firefly luciferase gene was generated, proliferation of these cells in irradiated severe combined immunodeficiency (SCID mice was monitored. Tumor cells were introduced into animals via subcutaneous, intraperitoneal and intravenous inoculation and whole body images, that revealed tumor location and growth kinetics, were obtained. The number of photons that were emitted from the labeled tumor cells and transmitted through murine tissues was sufficient to detect 1×103 cells in the peritoneal cavity, 1×104 cells at subcutaneous sites and 1×106 circulating cells immediately following injection. The kinetics of cell proliferation, as measured by photon emission, was exponential in the peritoneal cavity and at subcutaneous sites. Intravenous inoculation resulted in detectable colonies of tumor cells in animals receiving more than 1×103 cells. Our demonstrated ability to detect small numbers of tumor cells in living animals noninvasively suggests that therapies designed to treat minimal disease states, as occur early in the disease course and after elimination of the tumor mass, may be monitored using this approach. Moreover, it may be possible to monitor micrometastases and evaluate the molecular steps in the metastatic process. Spatiotemporal analyses of neoplasia will improve the predictability of animal models of human disease as study groups can be followed over time, this method will accelerate development of novel therapeutic

  20. Finite Element Modeling of Avascular Tumor Growth Using a Stress-Driven Model.

    Science.gov (United States)

    Iranmanesh, Faezeh; Nazari, Mohammad Ali

    2017-08-01

    Tumor growth being a multistage process has been investigated from different aspects. In the present study, an attempt is made to represent a constitutive-structure-based model of avascular tumor growth in which the effects of tensile stresses caused by collagen fibers are considered. Collagen fibers as a source of anisotropy in the structure of tissue are taken into account using a continuous fiber distribution formulation. To this end, a finite element modeling is implemented in which a neo-Hookean hyperelastic material is assigned to the tumor and its surrounding host. The tumor is supplied with a growth term. The growth term includes the effect of parameters such as nutrient concentration on the tumor growth and the tumor's solid phase content in the formulation. Results of the study revealed that decrease of solid phase is indicative of decrease in growth rate and the final steady-state value of tumor's radius. Moreover, fiber distribution affects the final shape of the tumor, and it could be used to control the shape and geometry of the tumor in complex morphologies. Finally, the findings demonstrated that the exerted stresses on the tumor increase as time passes. Compression of tumor cells leads to the reduction of tumor growth rate until it gradually reaches an equilibrium radius. This finding is in accordance with experimental data. Hence, this formulation can be deployed to evaluate both the residual stresses induced by growth and the mechanical interactions with the host tissue.

  1. Dwarf spheroidal galaxies: Keystones of galaxy evolution

    Science.gov (United States)

    Gallagher, John S., III; Wyse, Rosemary F. G.

    1994-01-01

    Dwarf spheroidal galaxies are the most insignificant extragalactic stellar systems in terms of their visibility, but potentially very significant in terms of their role in the formation and evolution of much more luminous galaxies. We discuss the present observational data and their implications for theories of the formation and evolution of both dwarf and giant galaxies. The putative dark-matter content of these low-surface-brightness systems is of particular interest, as is their chemical evolution. Surveys for new dwarf spheroidals hidden behind the stars of our Galaxy and those which are not bound to giant galaxies may give new clues as to the origins of this unique class of galaxy.

  2. Adult Lung Spheroid Cells Contain Progenitor Cells and Mediate Regeneration in Rodents With Bleomycin-Induced Pulmonary Fibrosis.

    Science.gov (United States)

    Henry, Eric; Cores, Jhon; Hensley, M Taylor; Anthony, Shirena; Vandergriff, Adam; de Andrade, James B M; Allen, Tyler; Caranasos, Thomas G; Lobo, Leonard J; Cheng, Ke

    2015-11-01

    Lung diseases are devastating conditions and ranked as one of the top five causes of mortality worldwide according to the World Health Organization. Stem cell therapy is a promising strategy for lung regeneration. Previous animal and clinical studies have focused on the use of mesenchymal stem cells (from other parts of the body) for lung regenerative therapies. We report a rapid and robust method to generate therapeutic resident lung progenitors from adult lung tissues. Outgrowth cells from healthy lung tissue explants are self-aggregated into three-dimensional lung spheroids in a suspension culture. Without antigenic sorting, the lung spheroids recapitulate the stem cell niche and contain a natural mixture of lung stem cells and supporting cells. In vitro, lung spheroid cells can be expanded to a large quantity and can form alveoli-like structures and acquire mature lung epithelial phenotypes. In severe combined immunodeficiency mice with bleomycin-induced pulmonary fibrosis, intravenous injection of human lung spheroid cells inhibited apoptosis, fibrosis, and infiltration but promoted angiogenesis. In a syngeneic rat model of pulmonary fibrosis, lung spheroid cells outperformed adipose-derived mesenchymal stem cells in reducing fibrotic thickening and infiltration. Previously, lung spheroid cells (the spheroid model) had only been used to study lung cancer cells. Our data suggest that lung spheroids and lung spheroid cells from healthy lung tissues are excellent sources of regenerative lung cells for therapeutic lung regeneration. The results from the present study will lead to future human clinical trials using lung stem cell therapies to treat various incurable lung diseases, including pulmonary fibrosis. The data presented here also provide fundamental knowledge regarding how injected stem cells mediate lung repair in pulmonary fibrosis. ©AlphaMed Press.

  3. Building Context with Tumor Growth Modeling Projects in Differential Equations

    Science.gov (United States)

    Beier, Julie C.; Gevertz, Jana L.; Howard, Keith E.

    2015-01-01

    The use of modeling projects serves to integrate, reinforce, and extend student knowledge. Here we present two projects related to tumor growth appropriate for a first course in differential equations. They illustrate the use of problem-based learning to reinforce and extend course content via a writing or research experience. Here we discuss…

  4. Computational Model for Tumor Oxygenation Applied to Clinical Data on Breast Tumor Hemoglobin Concentrations Suggests Vascular Dilatation and Compression.

    Directory of Open Access Journals (Sweden)

    Michael Welter

    Full Text Available We present a computational model for trans-vascular oxygen transport in synthetic tumor and host tissue blood vessel networks, aiming at qualitatively explaining published data of optical mammography, which were obtained from 87 breast cancer patients. The data generally show average hemoglobin concentration to be higher in tumors versus host tissue whereas average oxy-to total hemoglobin concentration (vascular segment RBC-volume-weighted blood oxygenation can be above or below normal. Starting from a synthetic arterio-venous initial network the tumor vasculature was generated by processes involving cooption, angiogenesis, and vessel regression. Calculations of spatially resolved blood flow, hematocrit, oxy- and total hemoglobin concentrations, blood and tissue oxygenation were carried out for ninety tumor and associated normal vessel networks starting from various assumed geometries of feeding arteries and draining veins. Spatial heterogeneity in the extra-vascular partial oxygen pressure distribution can be related to various tumor compartments characterized by varying capillary densities and blood flow characteristics. The reported higher average hemoglobin concentration of tumors is explained by growth and dilatation of tumor blood vessels. Even assuming sixfold metabolic rate of oxygen consumption in tumorous versus host tissue, the predicted oxygen hemoglobin concentrations are above normal. Such tumors are likely associated with high tumor blood flow caused by high-caliber blood vessels crossing the tumor volume and hence oxygen supply exceeding oxygen demand. Tumor oxy- to total hemoglobin concentration below normal could only be achieved by reducing tumor vessel radii during growth by a randomly selected factor, simulating compression caused by intra-tumoral solid stress due to proliferation of cells and extracellular matrix. Since compression of blood vessels will impede chemotherapy we conclude that tumors with oxy- to total

  5. Fluctuation of Parameters in Tumor Cell Growth Model

    Science.gov (United States)

    Ai, Bao-Quan; Wang, Xian-Ju; Liu, Guo-Tao; Liu, Liang-Gang

    2003-07-01

    We study the steady state properties of a logistic growth model in the presence of Gaussian white noise. Based on the corresponding Fokker-Planck equation the steady state solution of the probability distribution function and its extrema have been investigated. It is found that the fluctuation of the tumor birth rate reduces the population of the cells while the fluctuation of predation rate can prevent the population of tumor cells from going into extinction. Noise in the system can induce the phase transition. The project supported by National Natural Science Foundation of China under Grant No. 10275099 and Natural Science Foundation of Guangdong Province of China under Grant Nos. 021707 and 001182

  6. Application of Mie theory to assess structure of spheroidal scattering in backscattering geometries.

    Science.gov (United States)

    Chalut, Kevin J; Giacomelli, Michael G; Wax, Adam

    2008-08-01

    Inverse light scattering analysis seeks to associate measured scattering properties with the most probable theoretical scattering distribution. Although Mie theory is a spherical scattering model, it has been used successfully for discerning the geometry of spheroidal scatterers. The goal of this study was an in-depth evaluation of the consequences of analyzing the structure of spheroidal geometries, which are relevant to cell and tissue studies in biology, by employing Mie-theory-based inverse light scattering analysis. As a basis for this study, the scattering from spheroidal geometries was modeled using T-matrix theory and used as test data. In a previous study, we used this technique to investigate the case of spheroidal scatterers aligned with the optical axis. In the present study, we look at a broader scope which includes the effects of aspect ratio, orientation, refractive index, and incident light polarization. Over this wide range of parameters, our results indicate that this method provides a good estimate of spheroidal structure.

  7. 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....

  8. Stability of a charged, conducting, spheroidal droplet

    Science.gov (United States)

    Krappe, H. J.

    2018-02-01

    The stability of spheroidal, charged, conducting droplets is investigated. The effect of rotation and of external homogeneous electric fields on the equilibrium shape and on the limit of stability is also studied in close analogy to the behavior of volume-charged droplets considered in nuclear physics.

  9. Adoptively transferred human lung tumor specific cytotoxic T cells can control autologous tumor growth and shape tumor phenotype in a SCID mouse xenograft model

    Directory of Open Access Journals (Sweden)

    Ferrone Soldano

    2007-06-01

    Full Text Available Abstract Background The anti-tumor efficacy of human immune effector cells, such as cytolytic T lymphocytes (CTLs, has been difficult to study in lung cancer patients in the clinical setting. Improved experimental models for the study of lung tumor-immune cell interaction as well as for evaluating the efficacy of adoptive transfer of immune effector cells are needed. Methods To address questions related to the in vivo interaction of human lung tumor cells and immune effector cells, we obtained an HLA class I + lung tumor cell line from a fresh surgical specimen, and using the infiltrating immune cells, isolated and characterized tumor antigen-specific, CD8+ CTLs. We then established a SCID mouse-human tumor xenograft model with the tumor cell line and used it to study the function of the autologous CTLs provided via adoptive transfer. Results The tumor antigen specific CTLs isolated from the tumor were found to have an activated memory phenotype and able to kill tumor cells in an antigen specific manner in vitro. Additionally, the tumor antigen-specific CTLs were fully capable of homing to and killing autologous tumors in vivo, and expressing IFN-γ, each in an antigen-dependent manner. A single injection of these CTLs was able to provide significant but temporary control of the growth of autologous tumors in vivo without the need for IL-2. The timing of injection of CTLs played an essential role in the outcome of tumor growth control. Moreover, immunohistochemical analysis of surviving tumor cells following CTL treatment indicated that the surviving tumor cells expressed reduced MHC class I antigens on their surface. Conclusion These studies confirm and extend previous studies and provide additional information regarding the characteristics of CTLs which can be found within a patient's tumor. Moreover, the in vivo model described here provides a unique window for observing events that may also occur in patients undergoing adoptive cellular

  10. 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...

  11. PREDICTION OF THE EXTREMAL SHAPE FACTOR OF SPHEROIDAL PARTICLES

    Directory of Open Access Journals (Sweden)

    Daniel Hlubinka

    2011-05-01

    Full Text Available In the stereological unfolding problem for spheroidal particles the extremal shape factor is predicted. The theory of extreme values has been used to show that extremes of the planar shape factor of particle sections tend to the same limit distribution as extremes of the original shape factor for both the conditional and marginal distribution. Attention is then paid to the extreme shape factor conditioned by the particle size. Normalizing constants are evaluated for a parametric model and the numerical procedure is tested on real data from metallography.

  12. Cell invasion in the spheroid sprouting assay: a spatial organisation analysis adaptable to cell behaviour.

    Directory of Open Access Journals (Sweden)

    Silvia Blacher

    Full Text Available The endothelial cell spheroid assay provides a suitable in vitro model to study (lymph angiogenesis and test pro- and anti-(lymph angiogenic factors or drugs. Usually, the extent of cell invasion, observed through optical microscopy, is measured. The present study proposes the spatial distribution of migrated cells as a new descriptor of the (lymph angiogenic response. The utility of this novel method rests with its capacity to locally characterise spheroid structure, allowing not only the investigation of single and collective cell invasion but also the evolution of the spheroid core itself. Moreover, the proposed method can be applied to 2D-projected spheroid images obtained by optical microscopy, as well as to 3D images acquired by confocal microscopy. To validate the proposed methodology, endothelial cell invasion was evaluated under different experimental conditions. The results were compared with widely used global parameters. The comparison shows that our method prevents local spheroid modifications from being overlooked and leading to the possible misinterpretation of results.

  13. On the spheroidal graphite growth and the austenite solidification in ductile irons

    Science.gov (United States)

    Qing, Jingjing

    Evolutions of austenite and nodular/spheroidal graphite particles during solidifications of ductile irons were experimentally investigated. Spheroidal graphite particle and austenite dendrite were found nucleated independently in liquid. Austenite dendrite engulfed the spheroidal graphite particles after contact and an austenite shell formed around a spheroidal graphite particle. The graphite diameter at which the austenite shell closed around nodule was determined. Statistically determined graphite size distributions indicated multiple graphite nucleation events during solidification. Structures in a graphite nodule varied depending on the growth stages of the nodule in ductile iron. Curved graphene layers appearing as faceted growth ledges swept circumferentially around the surface of a graphite nodule at early growth stages. Mismatches between the growth fronts created gaps which divided a nodule into radially oriented conical substructures (3-D). Columnar substructure was observed in the periphery of a nodule (formed during the intermediate growth stages) on its 2-D cross section. A columnar substructure consisted of parallel peripheral grains, with their c-axes approximately parallel. Graphene layers continued building up in individual conical substructure, and a graphite nodule increased its size accordingly. Method for characterizing the crystal structures of graphite based on the selected area diffraction pattern was developed. Both hexagonal structure and rhombohedral structure were found in the spheroidal graphite particles. Possible crystallographic defects associated with hexagonal-rhombohedral structure transition were discussed. Schematic models for introducing tilt angles to the graphite lattice with basal plane tilt boundaries were constructed.

  14. Vertical and horizontal spheroidal boundary-value problems

    Science.gov (United States)

    Šprlák, Michal; Tangdamrongsub, Natthachet

    2017-12-01

    Vertical and horizontal spheroidal boundary-value problems (BVPs), i.e., determination of the external gravitational potential from the components of the gravitational gradient on the spheroid, are discussed in this article. The gravitational gradient is decomposed into the series of the vertical and horizontal vector spheroidal harmonics, before being orthogonalized in a weighted sense by two different approaches. The vertical and horizontal spheroidal BVPs are then formulated and solved in the spectral and spatial domains. Both orthogonalization methods provide the same analytical solutions for the vertical spheroidal BVP, and give distinct, but equivalent, analytical solutions for the horizontal spheroidal BVP. A closed-loop simulation is performed to test the correctness of the analytical solutions, and we investigate analytical properties of the sub-integral kernels. The systematic treatment of the spheroidal BVPs and the resulting mathematical equations extend the theoretical apparatus of geodesy and of the potential theory.

  15. Calcium-activated potassium channels mediated blood-brain tumor barrier opening in a rat metastatic brain tumor model

    Directory of Open Access Journals (Sweden)

    Ong John M

    2007-03-01

    Full Text Available Abstract Background The blood-brain tumor barrier (BTB impedes the delivery of therapeutic agents to brain tumors. While adequate delivery of drugs occurs in systemic tumors, the BTB limits delivery of anti-tumor agents into brain metastases. Results In this study, we examined the function and regulation of calcium-activated potassium (KCa channels in a rat metastatic brain tumor model. We showed that intravenous infusion of NS1619, a KCa channel agonist, and bradykinin selectively enhanced BTB permeability in brain tumors, but not in normal brain. Iberiotoxin, a KCa channel antagonist, significantly attenuated NS1619-induced BTB permeability increase. We found KCa channels and bradykinin type 2 receptors (B2R expressed in cultured human metastatic brain tumor cells (CRL-5904, non-small cell lung cancer, metastasized to brain, human brain microvessel endothelial cells (HBMEC and human lung cancer brain metastasis tissues. Potentiometric assays demonstrated the activity of KCa channels in metastatic brain tumor cells and HBMEC. Furthermore, we detected higher expression of KCa channels in the metastatic brain tumor tissue and tumor capillary endothelia as compared to normal brain tissue. Co-culture of metastatic brain tumor cells and brain microvessel endothelial cells showed an upregulation of KCa channels, which may contribute to the overexpression of KCa channels in tumor microvessels and selectivity of BTB opening. Conclusion These findings suggest that KCa channels in metastatic brain tumors may serve as an effective target for biochemical modulation of BTB permeability to enhance selective delivery of chemotherapeutic drugs to metastatic brain tumors.

  16. The energy of a prolate spheroidal shell in a uniform magnetic field

    Science.gov (United States)

    Koksharov, Yu. A.

    2017-04-01

    The problem of the energy of a spheroidal magnetic shell, solved by methods of classical electrodynamics, arises, in particular, upon the study of thin-wall biocompatible microcapsules in connection with a pressing issue of targeted drug delivery. The drug inside a microcapsule should be released from the shell at a required instant of time by destroying the capsule's shell. The placement inside a shell of magnetic nanoparticles sensitive to an external magnetic field theoretically makes it possible to solve both problems: to transport a capsule to the required place and to destroy its shell. In particular, the shell can be destroyed under the action of internal stress when the shape of a capsule is changed. In this paper, the analysis of the model of a magnetic microcapsule in the form of a prolate spheroidal shell is performed and formulas for the magnetostatic and magnetic free energy when the magnetic field is directed along the major axis of the spheroid are derived.

  17. Molecular and functional assessment of multicellular cancer spheroids produced in double emulsions enabled by efficient airway resistance based selective surface treatment

    Science.gov (United States)

    Ma, Xiao; Leth Jepsen, Morten; Ivarsen, Anne Kathrine R.; Knudsen, Birgitta R.; Ho, Yi-Ping

    2017-09-01

    Multicellular spheroids have garnered significant attention as an in vitro three-dimensional cancer model which can mimick the in vivo microenvironmental features. While microfluidics generated double emulsions have become a potential method to generate spheroids, challenges remain on the tedious procedures. Enabled by a novel ‘airway resistance’ based selective surface treatment, this study presents an easy and facile generation of double emulsions for the initiation and cultivation of multicellular spheroids in a scaffold-free format. Combining with our previously developed DNA nanosensors, intestinal spheroids produced in the double emulsions have shown an elevated activities of an essential DNA modifying enzyme, the topoisomerase I. The observed molecular and functional characteristics of spheroids produced in double emulsions are similar to the counterparts produced by the commercially available ultra-low attachment plates. However, the double emulsions excel for their improved uniformity, and the consistency of the results obtained by subsequent analysis of the spheroids. The presented technique is expected to ease the burden of producing spheroids and to promote the spheroids model for cancer or stem cell study.

  18. 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

  19. EMT/MET at the Crossroad of Stemness, Regeneration and Oncogenesis: The Ying-Yang Equilibrium Recapitulated in Cell Spheroids

    Directory of Open Access Journals (Sweden)

    Elvira Forte

    2017-07-01

    Full Text Available The epithelial-to-mesenchymal transition (EMT is an essential trans-differentiation process, which plays a critical role in embryonic development, wound healing, tissue regeneration, organ fibrosis, and cancer progression. It is the fundamental mechanism by which epithelial cells lose many of their characteristics while acquiring features typical of mesenchymal cells, such as migratory capacity and invasiveness. Depending on the contest, EMT is complemented and balanced by the reverse process, the mesenchymal-to-epithelial transition (MET. In the saving economy of the living organisms, the same (Ying-Yang tool is integrated as a physiological strategy in embryonic development, as well as in the course of reparative or disease processes, prominently fibrosis, tumor invasion and metastasis. These mechanisms and their related signaling (e.g., TGF-β and BMPs have been effectively studied in vitro by tissue-derived cell spheroids models. These three-dimensional (3D cell culture systems, whose phenotype has been shown to be strongly dependent on TGF-β-regulated EMT/MET processes, present the advantage of recapitulating in vitro the hypoxic in vivo micro-environment of tissue stem cell niches and their formation. These spheroids, therefore, nicely reproduce the finely regulated Ying-Yang equilibrium, which, together with other mechanisms, can be determinant in cell fate decisions in many pathophysiological scenarios, such as differentiation, fibrosis, regeneration, and oncogenesis. In this review, current progress in the knowledge of signaling pathways affecting EMT/MET and stemness regulation will be outlined by comparing data obtained from cellular spheroids systems, as ex vivo niches of stem cells derived from normal and tumoral tissues. The mechanistic correspondence in vivo and the possible pharmacological perspective will be also explored, focusing especially on the TGF-β-related networks, as well as others, such as SNAI1, PTEN, and EGR1. This

  20. Evaluation of Tumor Angiogenesis with a Second-Generation US Contrast Medium in a Rat Breast Tumor Model

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Eun Young [Samsung Medical Center, Sungkyunkwan University School of Medicine (Korea, Republic of); Lee, Sang Hoon; Kim, Hak Hee; Kim, Sung Moon; Shin, Myung Jin; Kim, Nam Kug; Gong, Gyung Yub [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

    2008-06-15

    Tumor angiogenesis is an important factor for tumor growth, treatment response and prognosis. Noninvasive imaging methods for the evaluation of tumor angiogenesis have been studied, but a method for the quantification of tumor angiogenesis has not been established. This study was designed to evaluate tumor angiogenesis in a rat breast tumor model by the use of a contrast enhanced ultrasound (US) examination with a second-generation US contrast agent. The alkylating agent 19N-ethyl-N-nitrosourea (ENU) was injected into the intraperitoneal cavity of 30-day-old female Sprague-Dawley rats. Three to four months later, breast tumors were detected along the mammary lines of the rats. A total of 17 breast tumors larger than 1 cm in nine rats were evaluated by gray-scale US, color Doppler US and contrast-enhanced US using SonoVue. The results were recorded as digital video images; time-intensity curves and hemodynamic parameters were analyzed. Pathological breast tumor specimens were obtained just after the US examinations. The tumor specimens were stained with hematoxylin and eosin (H and E) and the expression of CD31, an endothelial cell marker, was determined by immunohistochemical staining. We also evaluated the pathological diagnosis of the tumors and the microvessel density (MVD). Spearman's correlation and the Kruskal-Wallis test were used for the analysis. The pathological diagnoses were 11 invasive ductal carcinomas and six benign intraductal epithelial proliferations. The MVD did not correlate with the pathological diagnosis. However, blood volume (BV) showed a statistically significant correlation with MVD (Spearman's correlation, p < 0.05). Contrast-enhanced US using a second-generation US contrast material was useful for the evaluation of tumor angiogenesis of breast tumors in the rat.

  1. Enhancement of Ischemic Wound Healing by Spheroid Grafting of Human Adipose-Derived Stem Cells Treated with Low-Level Light Irradiation.

    Science.gov (United States)

    Park, In-Su; Chung, Phil-Sang; Ahn, Jin Chul

    2015-01-01

    We investigated whether low-level light irradiation prior to transplantation of adipose-derived stromal cell (ASC) spheroids in an animal skin wound model stimulated angiogenesis and tissue regeneration to improve functional recovery of skin tissue. The spheroid, composed of hASCs, was irradiated with low-level light and expressed angiogenic factors, including vascular endothelial growth factor (VEGF), basic fibroblast growth factor (FGF), and hepatocyte growth factor (HGF). Immunochemical staining analysis revealed that the spheroid of the hASCs was CD31+, KDR+, and CD34+. On the other hand, monolayer-cultured hASCs were negative for these markers. PBS, human adipose tissue-derived stromal cells, and the ASC spheroid were transplanted into a wound bed in athymic mice to evaluate the therapeutic effects of the ASC spheroid in vivo. The ASC spheroid transplanted into the wound bed differentiated into endothelial cells and remained differentiated. The density of vascular formations increased as a result of the angiogenic factors released by the wound bed and enhanced tissue regeneration at the lesion site. These results indicate that the transplantation of the ASC spheroid significantly improved functional recovery relative to both ASC transplantation and PBS treatment. These findings suggest that transplantation of an ASC spheroid treated with low-level light may be an effective form of stem cell therapy for treatment of a wound bed.

  2. 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.

  3. Fully-resolved prolate spheroids in turbulent channel flows: A lattice Boltzmann study

    Directory of Open Access Journals (Sweden)

    Amir Eshghinejadfard

    2017-09-01

    Full Text Available Particles are present in many natural and industrial multiphase flows. In most practical cases, particle shape is not spherical, leading to additional difficulties for numerical studies. In this paper, DNS of turbulent channel flows with finite-size prolate spheroids is performed. The geometry includes a straight wall-bounded channel at a frictional Reynolds number of 180 seeded with particles. Three different particle shapes are considered, either spheroidal (aspect ratio λ=2 or 4 or spherical (λ=1. Solid-phase volume fraction has been varied between 0.75% and 1.5%. Lattice Boltzmann method (LBM is used to model the fluid flow. The influence of the particles on the flow field is simulated by immersed boundary method (IBM. In this Eulerian-Lagrangian framework, the trajectory of each particle is computed individually. All particle-particle and particle-fluid interactions are considered (four-way coupling. Results show that, in the range of examined volume fractions, mean fluid velocity is reduced by addition of particles. However, velocity reduction by spheroids is much lower than that by spheres; 2% and 1.6%, compared to 4.6%. Maximum streamwise velocity fluctuations are reduced by addition of particle. By comparing particle and fluid velocities, it is seen that spheroids move faster than the fluid before reaching the same speed in the channel center. Spheres, on the other hand, move slower than the fluid in the buffer layer. Close to the wall, all particle types move faster than the fluid. Moreover, prolate spheroids show a preferential orientation in the streamwise direction, which is stronger close to the wall. Far from the wall, the orientation of spheroidal particles tends to isotropy.

  4. Fully-resolved prolate spheroids in turbulent channel flows: A lattice Boltzmann study

    Science.gov (United States)

    Eshghinejadfard, Amir; Hosseini, Seyed Ali; Thévenin, Dominique

    2017-09-01

    Particles are present in many natural and industrial multiphase flows. In most practical cases, particle shape is not spherical, leading to additional difficulties for numerical studies. In this paper, DNS of turbulent channel flows with finite-size prolate spheroids is performed. The geometry includes a straight wall-bounded channel at a frictional Reynolds number of 180 seeded with particles. Three different particle shapes are considered, either spheroidal (aspect ratio λ =2 or 4) or spherical (λ =1 ). Solid-phase volume fraction has been varied between 0.75% and 1.5%. Lattice Boltzmann method (LBM) is used to model the fluid flow. The influence of the particles on the flow field is simulated by immersed boundary method (IBM). In this Eulerian-Lagrangian framework, the trajectory of each particle is computed individually. All particle-particle and particle-fluid interactions are considered (four-way coupling). Results show that, in the range of examined volume fractions, mean fluid velocity is reduced by addition of particles. However, velocity reduction by spheroids is much lower than that by spheres; 2% and 1.6%, compared to 4.6%. Maximum streamwise velocity fluctuations are reduced by addition of particle. By comparing particle and fluid velocities, it is seen that spheroids move faster than the fluid before reaching the same speed in the channel center. Spheres, on the other hand, move slower than the fluid in the buffer layer. Close to the wall, all particle types move faster than the fluid. Moreover, prolate spheroids show a preferential orientation in the streamwise direction, which is stronger close to the wall. Far from the wall, the orientation of spheroidal particles tends to isotropy.

  5. Characterization and propagation of tumor initiating cells derived from colorectal liver metastases: trials, tribulations and a cautionary note.

    Directory of Open Access Journals (Sweden)

    Mark I James

    Full Text Available Tumor initiating cells (TIC are increasingly being put forward as a potential target for intervention within colorectal cancer. Whilst characterisation and outgrowth of these cells has been extensively undertaken in primary colorectal cancers, few data are available describing characteristics within the metastatic setting. Tissue was obtained from patients undergoing surgical resection for colorectal liver metastases, and processed into single cell suspension for assessment. Tumor initiating cells from liver metastases were characterised using combinations of EPCAM, Aldehyde dehydrogenase activity, CD133 and CD26. CD133 expression was significantly lower in patients who had received chemotherapy, but this was accounted for by a decrease observed in the male patient cohort only. ALDHhigh populations were rare (0.4 and 0.3% for EPCAM+/ALDHhigh/CD133- and EPCAM+/ALDHhigh/CD133+ populations respectively and below the limits of detection in 28% of samples. Spheroid outgrowth of metastatic tumor cells across all samples could not be readily achieved using standard spheroid-formation techniques, thus requiring further method validation to reliably propagate cells from the majority of tissues. Spheroid formation was not enhanced using additional growth factors or fibroblast co-culture, but once cells were passaged through NOD-SCID mice, spheroid formation was observed in 82% samples, accompanied by a significant increase in CD26. Order of spheroid forming ability was ALDHhigh>CD133>CD26. Samples sorted by these markers each had the ability to reform ALDHhigh, CD133 and CD26 positive populations to a similar extent, suggestive of a high degree of plasticity for each population. Ex vivo TIC models are increasingly being utilised to assess efficacy of therapeutic interventions. It is therefore essential that such investigations use well-characterised models that are able to sustain TIC populations across a large patient cohort in order that the inherent

  6. Molecular Understanding of Growth Inhibitory Effect from Irradiated to Bystander Tumor Cells in Mouse Fibrosarcoma Tumor Model.

    Directory of Open Access Journals (Sweden)

    Sejal Desai

    Full Text Available Even though bystander effects pertaining to radiation risk assessment has been extensively studied, the molecular players of radiation induced bystander effect (RIBE in the context of cancer radiotherapy are poorly known. In this regard, the present study is aimed to investigate the effect of irradiated tumor cells on the bystander counterparts in mouse fibrosarcoma (WEHI 164 cells tumor model. Mice co-implanted with WEHI 164 cells γ-irradiated with a lethal dose of 15 Gy and unirradiated (bystander WEHI 164 cells showed inhibited tumor growth, which was measured in terms of tumor volume and Luc+WEHI 164 cells based bioluminescence in vivo imaging. Histopathological analysis and other assays revealed decreased mitotic index, increased apoptosis and senescence in these tumor tissues. In addition, poor angiogenesis was observed in these tumor tissues, which was further confirmed by fluorescence imaging of tumor vascularisation and CD31 expression by immuno-histochemistry. Interestingly, the growth inhibitory bystander effect was exerted more prominently by soluble factors obtained from the irradiated tumor cells than the cellular fraction. Cytokine profiling of the supernatants obtained from the irradiated tumor cells showed increased levels of VEGF, Rantes, PDGF, GMCSF and IL-2 and decreased levels of IL-6 and SCF. Comparative proteomic analysis of the supernatants from the irradiated tumor cells showed differential expression of total 24 protein spots (21 up- and 3 down-regulated when compared with the supernatant from the unirradiated control cells. The proteins which showed substantially higher level in the supernatant from the irradiated cells included diphosphate kinase B, heat shock cognate, annexin A1, angiopoietin-2, actin (cytoplasmic 1/2 and stress induced phosphoprotein 1. However, the levels of proteins like annexin A2, protein S100 A4 and cofilin was found to be lower in this supernatant. In conclusion, our results provided deeper

  7. MR Vascular Fingerprinting in Stroke and Brain Tumors Models.

    Science.gov (United States)

    Lemasson, B; Pannetier, N; Coquery, N; Boisserand, Ligia S B; Collomb, Nora; Schuff, N; Moseley, M; Zaharchuk, G; Barbier, E L; Christen, T

    2016-11-24

    In this study, we evaluated an MRI fingerprinting approach (MRvF) designed to provide high-resolution parametric maps of the microvascular architecture (i.e., blood volume fraction, vessel diameter) and function (blood oxygenation) simultaneously. The method was tested in rats (n = 115), divided in 3 models: brain tumors (9 L, C6, F98), permanent stroke, and a control group of healthy animals. We showed that fingerprinting can robustly distinguish between healthy and pathological brain tissues with different behaviors in tumor and stroke models. In particular, fingerprinting revealed that C6 and F98 glioma models have similar signatures while 9 L present a distinct evolution. We also showed that it is possible to improve the results of MRvF and obtain supplemental information by changing the numerical representation of the vascular network. Finally, good agreement was found between MRvF and conventional MR approaches in healthy tissues and in the C6, F98, and permanent stroke models. For the 9 L glioma model, fingerprinting showed blood oxygenation measurements that contradict results obtained with a quantitative BOLD approach. In conclusion, MR vascular fingerprinting seems to be an efficient technique to study microvascular properties in vivo. Multiple technical improvements are feasible and might improve diagnosis and management of brain diseases.

  8. Cell Competition Drives the Formation of Metastatic Tumors in a Drosophila Model of Epithelial Tumor Formation

    DEFF Research Database (Denmark)

    Eichenlaub, Teresa; Cohen, Stephen M; Herranz, Héctor

    2016-01-01

    Cell competition is a homeostatic process in which proliferating cells compete for survival. Elimination of otherwise normal healthy cells through competition is important during development and has recently been shown to contribute to maintaining tissue health during organismal aging. The mechan......Cell competition is a homeostatic process in which proliferating cells compete for survival. Elimination of otherwise normal healthy cells through competition is important during development and has recently been shown to contribute to maintaining tissue health during organismal aging....... The mechanisms that allow for ongoing cell competition during adult life could, in principle, contribute to tumorigenesis. However, direct evidence supporting this hypothesis has been lacking. Here, we provide evidence that cell competition drives tumor formation in a Drosophila model of epithelial cancer. Cells...... of the Septin family protein Peanut. Cytokinesis failure due to downregulation of Peanut is required for tumorigenesis. This study provides evidence that the cellular mechanisms that drive cell competition during normal tissue growth can be co-opted to drive tumor formation and metastasis. Analogous mechanisms...

  9. Morphological and Functional Analysis of Hepatocyte Spheroids Generated on Poly-HEMA-Treated Surfaces under the Influence of Fetal Calf Serum and Nonparenchymal Cells

    Directory of Open Access Journals (Sweden)

    Augustinus Bader

    2013-03-01

    Full Text Available Poly (2-hydroxyethyl methacrylate (HEMA has been used as a clinical material, in the form of a soft hydrogel, for various surgical procedures, including endovascular surgery of liver. It is a clear liquid compound and, as a soft, flexible, water-absorbing material, has been used to make soft contact lenses from small, concave, spinning molds. Primary rat hepatocyte spheroids were created on a poly-HEMA-coated surface with the intention of inducing hepatic tissue formation and improving liver functions. We investigated spheroid formation of primary adult rat hepatocyte cells and characterized hepatic-specific functions under the special influence of fetal calf serum (FCS and nonparencymal cells (NPC up to six days in different culture systems (e.g., hepatocytes + FCS, hepatocytes – FCS, NPC + FCS, NPC – FCS, co-culture + FCS, co-culture – FCS in both the spheroid model and sandwich model. Immunohistologically, we detected gap junctions, Ito cell/Kupffer cells, sinusoidal endothelial cells and an extracellular matrix in the spheroid model. FCS has no positive effect in the sandwich model, but has a negative effect in the spheroid model on albumin production, and no influence in urea production in either model. We found more cell viability in smaller diameter spheroids than larger ones by using the apoptosis test. Furthermore, there is no positive influence of the serum or NPC on spheroid formation, suggesting that it may only depend on the physical condition of the culture system. Since the sandwich culture has been considered a “gold standard” in vitro culture model, the hepatocyte spheroids generated on the poly-HEMA-coated surface were compared with those in the sandwich model. Major liver-specific functions, such as albumin secretion and urea synthesis, were evaluated in both the spheroid and sandwich model. The synthesis performance in the spheroid compared to the sandwich culture increases approximately by a factor of 1

  10. Daunorubicin and doxorubicin but not BCNU have deleterious effects on organotypic multicellular spheroids of gliomas

    NARCIS (Netherlands)

    Kaaijk, P.; Troost, D.; de Boer, O. J.; van Amstel, P.; Bakker, P. J.; Leenstra, S.; Bosch, D. A.

    1996-01-01

    In the present study organotypic multicellular spheroids (OMS) were used to study the effects of chemotherapeutic agents on malignant gliomas. Compared with the frequently used cell line models, OMS have several advantages with respect to the preservation of the cellular heterogeneity and the

  11. Mathematical models of tumor heterogeneity and drug resistance

    Science.gov (United States)

    Greene, James

    In this dissertation we develop mathematical models of tumor heterogeneity and drug resistance in cancer chemotherapy. Resistance to chemotherapy is one of the major causes of the failure of cancer treatment. Furthermore, recent experimental evidence suggests that drug resistance is a complex biological phenomena, with many influences that interact nonlinearly. Here we study the influence of such heterogeneity on treatment outcomes, both in general frameworks and under specific mechanisms. We begin by developing a mathematical framework for describing multi-drug resistance to cancer. Heterogeneity is reflected by a continuous parameter, which can either describe a single resistance mechanism (such as the expression of P-gp in the cellular membrane) or can account for the cumulative effect of several mechanisms and factors. The model is written as a system of integro-differential equations, structured by the continuous "trait," and includes density effects as well as mutations. We study the limiting behavior of the model, both analytically and numerically, and apply it to study treatment protocols. We next study a specific mechanism of tumor heterogeneity and its influence on cell growth: the cell-cycle. We derive two novel mathematical models, a stochastic agent-based model and an integro-differential equation model, each of which describes the growth of cancer cells as a dynamic transition between proliferative and quiescent states. By examining the role all parameters play in the evolution of intrinsic tumor heterogeneity, and the sensitivity of the population growth to parameter values, we show that the cell-cycle length has the most significant effect on the growth dynamics. In addition, we demonstrate that the agent-based model can be approximated well by the more computationally efficient integro-differential equations, when the number of cells is large. The model is closely tied to experimental data of cell growth, and includes a novel implementation of

  12. Towards a more representative in vitro method for fish ecotoxicology: morphological and biochemical characterisation of three-dimensional spheroidal hepatocytes.

    Science.gov (United States)

    Baron, Matthew G; Purcell, Wendy M; Jackson, Simon K; Owen, Stewart F; Jha, Awadhesh N

    2012-11-01

    The use of fish primary cells and cell lines offer an in vitro alternative for assessment of chemical toxicity and the evaluation of environmental samples in ecotoxicology. However, their uses are not without limitations such as short culture periods and loss of functionality, particularly with primary tissue. While three-dimensional (spheroid) technology is now established for in vitro mammalian toxicity studies, to date it has not been considered for environmental applications in a model aquatic species. In this study we report development of a reproducible six-well plate, gyratory-mediated method for rainbow trout (Oncorhynchus mykiss) hepatocyte spheroid culture and compare their functional and biochemical status with two-dimensional (2D) monolayer hepatocytes. Primary liver spheroid formation was divided into two stages, immature (1-5 days) and mature (≥6 days) according to size, shape and changes in functional and biochemical parameters (protein, glucose, albumin and lactate dehydrogenase). Mature spheroids retained the morphological characteristics (smooth outer surface, tight cell-cell contacts) previously described for mammalian spheroids as demonstrated by light and scanning electron microscopy. Glucose production and albumin synthesis were significantly higher in mature spheroids when compared to conventional 2D monolayer cultures (P ecotoxicological studies.

  13. In processing of a spheroidized medium carbon steel, modelling with regression analysis of cutting forces and surface roughness affected by cutting parameters

    Directory of Open Access Journals (Sweden)

    Hüdayim Başak

    2016-08-01

    Full Text Available In this study, different spheronization heat treatment applied on a mild carbon steel during the machining was created main cutting forces and surface roughness value, were modeled by using multiple linear regression analysis. Main cutting force and surface roughness value which are dependent variable are described respectively rate of 94.6% and 94.2% by independent variables. The ANOVA significance test were used to determine dependent and independent variables correlations. Also, processing parameters variations such as effects on the feed rate, depth of cut and cutting force changes effect on surface roughness and main cutting force general effects were plotted to discuss.

  14. Universal timescales in the rheology of spheroid cell aggregates

    Science.gov (United States)

    Yu, Miao; Mahtabfar, Aria; Beleen, Paul; Foty, Ramsey; Zahn, Jeffrey; Shreiber, David; Liu, Liping; Lin, Hao

    2017-11-01

    The rheological properties of tissue play important roles in key biological processes including embryogenesis, cancer metastasis, and wound healing. Spheroid cell aggregate is a particularly interesting model system for the study of these phenomena. In the long time, they behave like drops with a surface tension. In the short, viscoelasticity also needs to be considered. In this work, we discover two coupled and universal timescales for spheroid aggregates. A total of 12 aggregate types (total aggregate number n =290) derived from L and GBM (glioblastoma multiforme) cells are studied with microtensiometer to obtain their surface tension. They are also allowed to relax upon release of the compression forces. The two timescales are observed during the relaxation process; their values do not depend on compression time nor the degree of deformation, and are consistent among all 12 types. Following prior work (Yu et al., Phys. Rev. Lett., 115:128303; Liu et al., J. Mech. Phys. Solids, 98:309-329) we use a rigorous mathematical theory to interpret the results, which reveals intriguing properties of the aggregates on both tissue and cellular levels. The mechanics of multicellular organization reflects both complexity and regularity due to strong active regulation.

  15. Distribution of PLGA-modified nanoparticles in 3D cell culture models of hypo-vascularized tumor tissue.

    Science.gov (United States)

    Sims, Lee B; Huss, Maya K; Frieboes, Hermann B; Steinbach-Rankins, Jill M

    2017-10-05

    Advanced stage cancer treatments are often invasive and painful-typically comprised of surgery, chemotherapy, and/or radiation treatment. Low transport efficiency during systemic chemotherapy may require high chemotherapeutic doses to effectively target cancerous tissue, resulting in systemic toxicity. Nanotherapeutic platforms have been proposed as an alternative to more safely and effectively deliver therapeutic agents directly to tumor sites. However, cellular internalization and tumor penetration are often diametrically opposed, with limited access to tumor regions distal from vasculature, due to irregular tissue morphologies. To address these transport challenges, nanoparticles (NPs) are often surface-modified with ligands to enhance transport and longevity after localized or systemic administration. Here, we evaluate stealth polyethylene-glycol (PEG), cell-penetrating (MPG), and CPP-stealth (MPG/PEG) poly(lactic-co-glycolic-acid) (PLGA) NP co-treatment strategies in 3D cell culture representing hypo-vascularized tissue. Smaller, more regularly-shaped avascular tissue was generated using the hanging drop (HD) method, while more irregularly-shaped masses were formed with the liquid overlay (LO) technique. To compare NP distribution differences within the same type of tissue as a function of different cancer types, we selected HeLa, cervical epithelial adenocarcinoma cells; CaSki, cervical epidermoid carcinoma cells; and SiHa, grade II cervical squamous cell carcinoma cells. In HD tumors, enhanced distribution relative to unmodified NPs was measured for MPG and PEG NPs in HeLa, and for all modified NPs in SiHa spheroids. In LO tumors, the greatest distribution was observed for MPG and MPG/PEG NPs in HeLa, and for PEG and MPG/PEG NPs in SiHa spheroids. Pre-clinical evaluation of PLGA-modified NP distribution into hypo-vascularized tumor tissue may benefit from considering tissue morphology in addition to cancer type.

  16. Cat Mammary Tumors: Genetic Models for the Human Counterpart

    Directory of Open Access Journals (Sweden)

    Filomena Adega

    2016-08-01

    Full Text Available The records are not clear, but Man has been sheltering the cat inside his home for over 12,000 years. The close proximity of this companion animal, however, goes beyond sharing the same roof; it extends to the great similarity found at the cellular and molecular levels. Researchers have found a striking resemblance between subtypes of feline mammary tumors and their human counterparts that goes from the genes to the pathways involved in cancer initiation and progression. Spontaneous cat mammary pre-invasive intraepithelial lesions (hyperplasias and neoplasias and malignant lesions seem to share a wide repertoire of molecular features with their human counterparts. In the present review, we tried to compile all the genetics aspects published (i.e., chromosomal alterations, critical cancer genes and their expression regarding cat mammary tumors, which support the cat as a valuable alternative in vitro cell and animal model (i.e., cat mammary cell lines and the spontaneous tumors, respectively, but also to present a critical point of view of some of the issues that really need to be investigated in future research.

  17. Repopulation of interacting tumor cells during fractionated radiotherapy: stochastic modeling of the tumor control probability.

    Science.gov (United States)

    Fakir, Hatim; Hlatky, Lynn; Li, Huamin; Sachs, Rainer

    2013-12-01

    Optimal treatment planning for fractionated external beam radiation therapy requires inputs from radiobiology based on recent thinking about the "five Rs" (repopulation, radiosensitivity, reoxygenation, redistribution, and repair). The need is especially acute for the newer, often individualized, protocols made feasible by progress in image guided radiation therapy and dose conformity. Current stochastic tumor control probability (TCP) models incorporating tumor repopulation effects consider "stem-like cancer cells" (SLCC) to be independent, but the authors here propose that SLCC-SLCC interactions may be significant. The authors present a new stochastic TCP model for repopulating SLCC interacting within microenvironmental niches. Our approach is meant mainly for comparing similar protocols. It aims at practical generalizations of previous mathematical models. The authors consider protocols with complete sublethal damage repair between fractions. The authors use customized open-source software and recent mathematical approaches from stochastic process theory for calculating the time-dependent SLCC number and thereby estimating SLCC eradication probabilities. As specific numerical examples, the authors consider predicted TCP results for a 2 Gy per fraction, 60 Gy protocol compared to 64 Gy protocols involving early or late boosts in a limited volume to some fractions. In sample calculations with linear quadratic parameters α = 0.3 per Gy, α∕β = 10 Gy, boosting is predicted to raise TCP from a dismal 14.5% observed in some older protocols for advanced NSCLC to above 70%. This prediction is robust as regards: (a) the assumed values of parameters other than α and (b) the choice of models for intraniche SLCC-SLCC interactions. However, α = 0.03 per Gy leads to a prediction of almost no improvement when boosting. The predicted efficacy of moderate boosts depends sensitively on α. Presumably, the larger values of α are the ones appropriate for individualized

  18. Repopulation of interacting tumor cells during fractionated radiotherapy: Stochastic modeling of the tumor control probability

    International Nuclear Information System (INIS)

    Fakir, Hatim; Hlatky, Lynn; Li, Huamin; Sachs, Rainer

    2013-01-01

    Purpose: Optimal treatment planning for fractionated external beam radiation therapy requires inputs from radiobiology based on recent thinking about the “five Rs” (repopulation, radiosensitivity, reoxygenation, redistribution, and repair). The need is especially acute for the newer, often individualized, protocols made feasible by progress in image guided radiation therapy and dose conformity. Current stochastic tumor control probability (TCP) models incorporating tumor repopulation effects consider “stem-like cancer cells” (SLCC) to be independent, but the authors here propose that SLCC-SLCC interactions may be significant. The authors present a new stochastic TCP model for repopulating SLCC interacting within microenvironmental niches. Our approach is meant mainly for comparing similar protocols. It aims at practical generalizations of previous mathematical models. Methods: The authors consider protocols with complete sublethal damage repair between fractions. The authors use customized open-source software and recent mathematical approaches from stochastic process theory for calculating the time-dependent SLCC number and thereby estimating SLCC eradication probabilities. As specific numerical examples, the authors consider predicted TCP results for a 2 Gy per fraction, 60 Gy protocol compared to 64 Gy protocols involving early or late boosts in a limited volume to some fractions. Results: In sample calculations with linear quadratic parameters α = 0.3 per Gy, α/β = 10 Gy, boosting is predicted to raise TCP from a dismal 14.5% observed in some older protocols for advanced NSCLC to above 70%. This prediction is robust as regards: (a) the assumed values of parameters other than α and (b) the choice of models for intraniche SLCC-SLCC interactions. However, α = 0.03 per Gy leads to a prediction of almost no improvement when boosting. Conclusions: The predicted efficacy of moderate boosts depends sensitively on α. Presumably, the larger values of α are

  19. Pancreas tumor model in rabbit imaged by perfusion CT scans

    Science.gov (United States)

    Gunn, Jason; Tichauer, Kenneth; Moodie, Karen; Kane, Susan; Hoopes, Jack; Stewart, Errol E.; Hadway, Jennifer; Lee, Ting-Yim; Pereira, Stephen P.; Pogue, Brian W.

    2013-03-01

    The goal of this work was to develop and validate a pancreas tumor animal model to investigate the relationship between photodynamic therapy (PDT) effectiveness and photosensitizer drug delivery. More specifically, this work lays the foundation for investigating the utility of dynamic contrast enhanced blood perfusion imaging to be used to inform subsequent PDT. A VX2 carcinoma rabbit cell line was grown in the tail of the pancreas of three New Zealand White rabbits and approximately 3-4 weeks after implantation the rabbits were imaged on a CT scanner using a contrast enhanced perfusion protocol, providing parametric maps of blood flow, blood volume, mean transit time, and vascular permeability surface area product.

  20. Modeling tumor-associated edema in gliomas during anti-angiogenic therapy and its impact on imageable tumor

    Directory of Open Access Journals (Sweden)

    Andrea eHawkins-Daarud

    2013-04-01

    Full Text Available Glioblastoma, the most aggressive form of primary brain tumor is predominantly assessed with gadolinium-enhanced T1-weighted (T1Gd and T2-weighted magnetic resonance imaging (MRI. Pixel intensity enhancement on the T1Gd image is understood to correspond to the gadolinium contrast agent leaking from the tumor-induced neovasculature, while hyperintensity on the T2/FLAIR images corresponds with edema and infiltrated tumor cells. None of these modalities directly show tumor cells; rather, they capture abnormalities in the microenvironment caused by the presence of tumor cells. Thus, assessing disease response after treatments impacting the microenvironment remains challenging through the obscuring lens of MR imaging. Anti-angiogenic therapies have been used in the treatment of gliomas with spurious results ranging from no apparent response to significant imaging improvement with the potential for extremely diffuse patterns of tumor recurrence on imaging and autopsy. Anti-angiogenic treatment normalizes the vasculature, effectively decreasing vessel permeability and thus reducing tumor-induced edema, drastically altering T2-weighted MRI. We extend a previously developed mathematical model of glioma growth to explicitly incorporate edema formation allowing us to directly characterize and potentially predict the effects of anti-angiogenics on imageable tumor growth. A comparison of simulated glioma growth and imaging enhancement with and without bevacizumab supports the current understanding that anti-angiogenic treatment can serve as a surrogate for steroids and the clinically-driven hypothesis that anti-angiogenic treatment may not have any significant effect on the growth dynamics of the overall tumor-cell populations. However, the simulations do illustrate a potentially large impact on the level of edematous extracellular fluid, and thus on what would be imageable on T2/FLAIR MR for tumors with lower proliferation rates.

  1. Process for producing uranium carbide spheroids

    International Nuclear Information System (INIS)

    Shennan, J.V.; Ford, L.H.

    1977-01-01

    The invention deals with a method to fabricate UC spheroids which are filled into moulds made of refractory material for fuel elements. The UC fuel particles are double-coated: a first thin layer of pyrolytic carbon is coated at low temperature 1200-1400 0 C, a record layer of pyrolytic material (e.g. Si c) is coated at a higher temperature (above 1500 0 C) which holds back the fission products. The method is described more closely by means of an example. (GSC) [de

  2. Process for producing uranium carbide spheroids

    International Nuclear Information System (INIS)

    Shennan, J.V.; Ford, L.H.

    1976-01-01

    The invention deals with a method to produce UC spheroids which are filled into molded bodies of fire-proof material for fuel elements. The UC fuel particles are doubly coated: a first thin layer of pyrolytic carbon is coated at low temperature (1,200-1,400 0 C), a second layer of fire-proof material (e.g. SiC) is coated at a higher temperature (above 1,500 0 C) which holds back the fission products. The process is explained in more detail using an example. (GSCH) [de

  3. The development and characterization of a human mesothelioma in vitro 3D model to investigate immunotoxin therapy.

    Directory of Open Access Journals (Sweden)

    Xinran Xiang

    2011-01-01

    Full Text Available Tumor microenvironments present significant barriers to penetration by antibodies and immunoconjugates. Tumor microenvironments, however, are difficult to study in vitro. Cells cultured as monolayers exhibit less resistance to therapy than those grown in vivo and an alternative research model more representative of the in vivo tumor is more desirable. SS1P is an immunotoxin composed of the Fv portion of a mesothelin-specific antibody fused to a bacterial toxin that is presently undergoing clinical trials in mesothelioma.Here, we examined how the tumor microenvironment affects the penetration and killing activity of SS1P in a new three-dimensional (3D spheroid model cultured in vitro using the human mesothelioma cell line (NCI-H226 and two primary cell lines isolated from the ascites of malignant mesothelioma patients. Mesothelioma cells grown as monolayers or as spheroids expressed comparable levels of mesothelin; however, spheroids were at least 100 times less affected by SS1P. To understand this disparity in cytotoxicity, we made fluorescence-labeled SS1P molecules and used confocal microscopy to examine the time course of SS1P penetration within spheroids. The penetration was limited after 4 hours. Interestingly, we found a significant increase in the number of tight junctions in the core area of spheroids by electron microscopy. Expression of E-Cadherin, a protein involved in the assembly and sealing of tight junctions and highly expressed in malignant mesothelioma, was found significantly increased in spheroids as compared to monolayers. Moreover, we found that siRNA silencing and antibody inhibition targeting E-Cadherin could enhance SS1P immunotoxin therapy in vitro.This work is one of the first to investigate immunotoxins in 3D tumor spheroids in vitro. This initial description of an in vitro tumor model may offer a simple and more representative model of in vivo tumors and will allow for further investigations of the microenvironmental

  4. Electromagnetic waves in irregular multilayered spheroidal structures of finite conductivity: full wave solutions

    International Nuclear Information System (INIS)

    Bahar, E.

    1976-01-01

    The propagation of electromagnetic waves excited by electric dipoles oriented along the axis of multilayered spheroidal structures of finite conductivity is investigated. The electromagnetic parameters and the thickness of the layers of the structure are assumed to be functions of the latitude. In the analysis, electric and magnetic field transforms that constitute a discrete and a continuous spectrum of spherical waves are used to provide a suitable basis for the expansion of the electromagnetic fields at any point in the irregular spheroidal structure. For spheroidal structures with good conducting cores, the terms in the solutions associated with the continuous part of the wave spectrum vanish. In general, however, when the skin depth for the core is large compared to its dimensions or when the sources are located in the core of the structure and propagation in the core is of special interest, the contribution from the continuous part of the wave spectrum cannot be neglected. At each interface between the layers of the irregular spheroidal structure, exact boundary conditions are imposed. Since the terms of the field expansions in the irregular structure do not individually satisfy the boundary conditions, Maxwell's equations are reduced to sets of coupled ordinary first-order differential equations for the wave amplitudes. The solutions are shown to satisfy the reciprocity relationships in electromagnetic theory. The analysis may be applied to problems of radio wave propagation in a nonuniform model of the earth-ionosphere waveguide, particularly when focusing effects at the antipodes are important

  5. Quantitative Microfluidic Dynamics Of Spheroidal Particles Within Periodic Optical Landscapes

    Science.gov (United States)

    Conover, Brandon Lee

    2011-12-01

    Over the past 4 decades, research and development of optical manipulation techniques has been primarily focused on observable phenomena. Trapping, sorting, mixing, aligning, and organizing particles---often times spheres on the order of 1 -- 100mum---has been shown by several groups using many different optical trapping and optical potential techniques. However, relatively little been reported on either the quantification of the various forces on the particles or on the theoretical aspects of the motion of the particles. Even less has been reported regarding the theoretical aspects of the motion of non-spherical particles within optical traps and landscapes. It is the objective of this dissertation to address these deficits by means of modeling and experimentally verifying the behavior of particles within periodic optical landscapes. First, we report on our development of a quantifiable analysis of these phenomena by means of a form factor model of spheroidal particle motion in periodic optical landscapes. Using this model, we show that shape does indeed have a quantifiable impact on a particle's motion in an optical landscape. We conclude that a collection of particles will all traverse an optical landscape differently based directly on their respective sizes, refractive indices, and shapes, sometimes with a high degree of dispersion. Next, we report on our development of a second model of spheroidal particle motion in periodic optical landscapes. Based on the T-matrix scattering approach, this model addresses the scattering forces and the electric field polarization effects on the particles' motion. We conclude that as the particle size gets larger, the scattering forces become greater and very quickly rise above an order of magnitude larger than the gradient forces of the optical landscape. Our conclusions provide quantifiable conditions for when scattering forces and electric field-induced torques within an optical landscape are significant and should not be

  6. Plasma spheroidization of nickel powders in a plasma reactor

    Indian Academy of Sciences (India)

    Unknown

    Heat treatment and phase changes. • Use of the plasma environment to synthesis metastable ... aimed for thermal treatment of powder (spheroidization, densification and purification) use either arc or inductive plasma ... cles leave the flame and get quenched. During the pro- cess the molten particles get spheroidized due to ...

  7. Tumor Growth Model with PK Input for Neuroblastoma Drug Development

    Science.gov (United States)

    2015-09-01

    is the most common extracranial solid tumor of childhood accounting for approximately 8-10% of all pediatric malignancies and 15% of cancer deaths in...participants were able to present their results to date at the annual American Association for Cancer Research annual meeting in April, 2015.  How...individual tumors. Using IHC techniques we will measure tumor response spatial patterns ( bread loafing fixed tumor tissue). We will use IHC

  8. Use of the vasodilator sodium nitroprusside during local hyperthermia: effects on tumor temperature and tumor response in a rat tumor model

    International Nuclear Information System (INIS)

    Krossnes, Baard Kronen; Mella, Olav; Dahl, Olav

    1996-01-01

    .3 and 0.4 deg. C higher during SNP infusion in the MFF and pentobarbital group, respectively. Conclusion: We have developed a small animal model in inbred rats feasible for exploring the influence of a stable blood pressure reduction induced by SNP, on the effect of HT given alone or in combination with other treatment modalities to a transplantable tumor. The greatly increased cytotoxic effect of local waterbath HT in the present tumor response experiments is probably a consequence of increased tumor temperature during SNP infusion

  9. Leukoencephalopathy with spheroids (HDLS) and pigmentary leukodystrophy (POLD)

    Science.gov (United States)

    Wider, C; Van Gerpen, J A.; DeArmond, S; Shuster, E A.; Dickson, D W.; Wszolek, Z K.

    2009-01-01

    Hereditary diffuse leukoencephalopathy with axonal spheroids (HDLS) and familial pigmentary orthochromatic leukodystrophy (POLD) present as adult-onset dementia with motor impairment and epilepsy. They are regarded as distinct diseases. We review data from the literature that support their being a single entity. Apart from a slightly older age at onset, a more rapid course, and more prominent pyramidal tract involvement, familial POLD is clinically similar to HDLS. Moreover, the pathologic hallmarks of the two diseases, axonal spheroids in HDLS and pigmented macrophages in POLD, can be identified in both conditions. This supports HDLS and POLD being referred collectively as adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP). GLOSSARY ALSP = adult-onset leukoencephalopathy with axonal spheroids and pigmented glia; HDLS = hereditary diffuse leukoencephalopathy with axonal spheroids; OLD = orthochromatic leukodystrophy; POLD = pigmentary orthochromatic leukodystrophy. PMID:19487654

  10. Human Organotypic Lung Tumor Models: Suitable For Preclinical 18F-FDG PET-Imaging.

    Directory of Open Access Journals (Sweden)

    David Fecher

    Full Text Available Development of predictable in vitro tumor models is a challenging task due to the enormous complexity of tumors in vivo. The closer the resemblance of these models to human tumor characteristics, the more suitable they are for drug-development and -testing. In the present study, we generated a complex 3D lung tumor test system based on acellular rat lungs. A decellularization protocol was established preserving the architecture, important ECM components and the basement membrane of the lung. Human lung tumor cells cultured on the scaffold formed cluster and exhibited an up-regulation of the carcinoma-associated marker mucin1 as well as a reduced proliferation rate compared to respective 2D culture. Additionally, employing functional imaging with 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography (FDG-PET these tumor cell cluster could be detected and tracked over time. This approach allowed monitoring of a targeted tyrosine kinase inhibitor treatment in the in vitro lung tumor model non-destructively. Surprisingly, FDG-PET assessment of single tumor cell cluster on the same scaffold exhibited differences in their response to therapy, indicating heterogeneity in the lung tumor model. In conclusion, our complex lung tumor test system features important characteristics of tumors and its microenvironment and allows monitoring of tumor growth and -metabolism in combination with functional imaging. In longitudinal studies, new therapeutic approaches and their long-term effects can be evaluated to adapt treatment regimes in future.

  11. The Carina dwarf spheroidal galaxy - How dark is it?

    Science.gov (United States)

    Mateo, Mario; Olszewski, Edward W.; Pryor, Carlton; Welch, Douglas L.; Fischer, Philippe

    1993-01-01

    Precise radial velocities obtained with a photon-counting echelle spectrograph for a sample of 17 red giants in the Carina dwarf spheroidal galaxy are presented. The calculation of the systemic velocity and central velocity dispersion of Carina is described, the existing data constraining the structural parameters of Carina are reviewed, and an estimate of the central surface brightness of the galaxy is derived. These data are used to estimate the central mass density of Carina, as well as central and global mass-to-light ratios. It is concluded that the inferred mass densities and mass-density limits for all acceptable models imply the presence of a significant DM component in Carina. DM properties of all well-studied dSph systems are summarized and compared.

  12. Effects of Mechanical Properties on Tumor Invasion: Insights from a Cellular Model

    KAUST Repository

    Li, YZ

    2014-08-01

    Understanding the regulating mechanism of tumor invasion is of crucial importance for both fundamental cancer research and clinical applications. Previous in vivo experiments have shown that invasive cancer cells dissociate from the primary tumor and invade into the stroma, forming an irregular invasive morphology. Although cell movements involved in tumor invasion are ultimately driven by mechanical forces of cell-cell interactions and tumor-host interactions, how these mechanical properties affect tumor invasion is still poorly understood. In this study, we use a recently developed two-dimensional cellular model to study the effects of mechanical properties on tumor invasion. We study the effects of cell-cell adhesions as well as the degree of degradation and stiffness of extracellular matrix (ECM). Our simulation results show that cell-cell adhesion relationship must be satisfied for tumor invasion. Increased adhesion to ECM and decreased adhesion among tumor cells result in invasive tumor behaviors. When this invasive behavior occurs, ECM plays an important role for both tumor morphology and the shape of invasive cancer cells. Increased stiffness and stronger degree of degradation of ECM promote tumor invasion, generating more aggressive tumor invasive morphologies. It can also generate irregular shape of invasive cancer cells, protruding towards ECM. The capability of our model suggests it a useful tool to study tumor invasion and might be used to propose optimal treatment in clinical applications.

  13. Dynamic density functional theory of solid tumor growth: Preliminary models

    Directory of Open Access Journals (Sweden)

    Arnaud Chauviere

    2012-03-01

    Full Text Available Cancer is a disease that can be seen as a complex system whose dynamics and growth result from nonlinear processes coupled across wide ranges of spatio-temporal scales. The current mathematical modeling literature addresses issues at various scales but the development of theoretical methodologies capable of bridging gaps across scales needs further study. We present a new theoretical framework based on Dynamic Density Functional Theory (DDFT extended, for the first time, to the dynamics of living tissues by accounting for cell density correlations, different cell types, phenotypes and cell birth/death processes, in order to provide a biophysically consistent description of processes across the scales. We present an application of this approach to tumor growth.

  14. A 3D printed microfluidic perfusion device for multicellular spheroid cultures.

    Science.gov (United States)

    Ong, Louis Jun Ye; Islam, Anik; DasGupta, Ramanuj; Iyer, Narayanan Gopalakkrishna; Leo, Hwa Liang; Toh, Yi-Chin

    2017-09-11

    The advent of 3D printing technologies promises to make microfluidic organ-on-chip technologies more accessible for the biological research community. To date, hydrogel-encapsulated cells have been successfully incorporated into 3D printed microfluidic devices. However, there is currently no 3D printed microfluidic device that can support multicellular spheroid culture, which facilitates extensive cell-cell contacts important for recapitulating many multicellular functional biological structures. Here, we report a first instance of fabricating a 3D printed microfluidic cell culture device capable of directly immobilizing and maintaining the viability and functionality of 3D multicellular spheroids. We evaluated the feasibility of two common 3D printing technologies i.e. stereolithography (SLA) and PolyJet printing, and found that SLA could prototype a device comprising of cell immobilizing micro-structures that were housed within a microfluidic network with higher fidelity. We have also implemented a pump-free perfusion system, relying on gravity-driven flow to perform medium perfusion in order to reduce the complexity and footprint of the device setup, thereby improving its adaptability into a standard biological laboratory. Finally, we demonstrated the biological performance of the 3D printed device by performing pump-free perfusion cultures of patient-derived parental and metastatic oral squamous cell carcinoma tumor and liver cell (HepG2) spheroids with good cell viability and functionality. This paper presents a proof-of-concept in simplifying and integrating the prototyping and operation of a microfluidic spheroid culture device, which will facilitate its applications in various drug efficacy, metabolism and toxicity studies.

  15. Investigation of HIFU-induced anti-tumor immunity in a murine tumor model

    Directory of Open Access Journals (Sweden)

    Lyerly H Kim

    2007-07-01

    Full Text Available Abstract Background High intensity focused ultrasound (HIFU is an emerging non-invasive treatment modality for localized treatment of cancers. While current clinical strategies employ HIFU exclusively for thermal ablation of the target sites, biological responses associated with both thermal and mechanical damage from focused ultrasound have not been thoroughly investigated. In particular, endogenous danger signals from HIFU-damaged tumor cells may trigger the activation of dendritic cells. This response may play a critical role in a HIFU-elicited anti-tumor immune response which can be harnessed for more effective treatment. Methods Mice bearing MC-38 colon adenocarcinoma tumors were treated with thermal and mechanical HIFU exposure settings in order to independently observe HIFU-induced effects on the host's immunological response. In vivo dendritic cell activity was assessed along with the host's response to challenge tumor growth. Results Thermal and mechanical HIFU were found to increase CD11c+ cells 3.1-fold and 4-fold, respectively, as compared to 1.5-fold observed for DC injection alone. In addition, thermal and mechanical HIFU increased CFSE+ DC accumulation in draining lymph nodes 5-fold and 10-fold, respectively. Moreover, focused ultrasound treatments not only caused a reduction in the growth of primary tumors, with tumor volume decreasing by 85% for thermal HIFU and 43% for mechanical HIFU, but they also provided protection against subcutaneous tumor re-challenge. Further immunological assays confirmed an enhanced CTL activity and increased tumor-specific IFN-γ-secreting cells in the mice treated by focused ultrasound, with cytotoxicity induced by mechanical HIFU reaching as high as 27% at a 10:1 effector:target ratio. Conclusion These studies present initial encouraging results confirming that focused ultrasound treatment can elicit a systemic anti-tumor immune response, and they suggest that this immunity is closely related to

  16. Differentiation and selection of hepatocyte precursors in suspension spheroid culture of transgenic murine embryonic stem cells.

    Directory of Open Access Journals (Sweden)

    Elke Gabriel

    Full Text Available Embryonic stem cell-derived hepatocyte precursor cells represent a promising model for clinical transplantations to diseased livers, as well as for establishment of in vitro systems for drug metabolism and toxicology investigations. This study aimed to establish an in vitro culture system for scalable generation of hepatic progenitor cells. We used stable transgenic clones of murine embryonic stem cells possessing a reporter/selection vector, in which the enhanced green fluorescent protein- and puromycin N-acetyltransferase-coding genes are driven by a common alpha-fetoprotein gene promoter. This allowed for "live" monitoring and puromycin selection of the desired differentiating cell type possessing the activated alpha-fetoprotein gene. A rotary culture system was established, sequentially yielding initially partially selected hepatocyte lineage-committed cells, and finally, a highly purified cell population maintained as a dynamic suspension spheroid culture, which progressively developed the hepatic gene expression phenotype. The latter was confirmed by quantitative RT-PCR analysis, which showed a progressive up-regulation of hepatic genes during spheroid culture, indicating development of a mixed hepatocyte precursor-/fetal hepatocyte-like cell population. Adherent spheroids gave rise to advanced differentiated hepatocyte-like cells expressing hepatic proteins such as albumin, alpha-1-antitrypsin, cytokeratin 18, E-cadherin, and liver-specific organic anion transporter 1, as demonstrated by fluorescent immunostaining. A fraction of adherent cells was capable of glycogen storage and of reversible up-take of indocyanine green, demonstrating their hepatocyte-like functionality. Moreover, after transplantation of spheroids into the mouse liver, the spheroid-derived cells integrated into recipient. These results demonstrate that large-scale hepatocyte precursor-/hepatocyte-like cultures can be established for use in clinical trials, as well as in

  17. Two-Photon Microscopy Analysis of Gold Nanoparticle Uptake in 3D Cell Spheroids.

    Directory of Open Access Journals (Sweden)

    Tushar D Rane

    Full Text Available Nanomaterials can be synthesized from a wide range of material systems in numerous morphologies, creating an extremely diverse portfolio. As result of this tunability, these materials are emerging as a new class of nanotherapeutics and imaging agents. One particularly interesting nanomaterial is the gold nanoparticle. Due to its inherent biocompatibility and tunable photothermal behavior, it has made a rapid transition from the lab setting to in vivo testing. In most nanotherapeutic applications, the efficacy of the agent is directly related to the target of interest. However, the optimization of the AuNP size and shape for efficacy in vitro, prior to testing in in vivo models of a disease, has been largely limited to two dimensional monolayers of cells. Two dimensional cell cultures are unable to reproduce conditions experienced by AuNP in the body. In this article, we systematically investigate the effect of different properties of AuNP on the penetration depth into 3D cell spheroids using two-photon microscopy. The 3D spheroids are formed from the HCT116 cell line, a colorectal carcinoma cell line. In addition to studying different sizes and shapes of AuNPs, we also study the effect of an oligo surface chemistry. There is a significant difference between AuNP uptake profiles in the 2D monolayers of cells as compared to the 3D cell spheroids. Additionally, the range of sizes and shapes studied here also exhibit marked differences in uptake penetration depth and efficacy. Finally, our results demonstrate that two-photon microscopy enables quantitative AuNP localization and concentration data to be obtained at the single spheroid level without fluorescent labeling of the AuNP, thus, providing a viable technique for large scale screening of AuNP properties in 3D cell spheroids as compared to tedious and time consuming techniques like electron microscopy.

  18. 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.

  19. Cell number per spheroid and electrical conductivity of nanowires influence the function of silicon nanowired human cardiac spheroids.

    Science.gov (United States)

    Tan, Yu; Richards, Dylan; Coyle, Robert C; Yao, Jenny; Xu, Ruoyu; Gou, Wenyu; Wang, Hongjun; Menick, Donald R; Tian, Bozhi; Mei, Ying

    2017-03-15

    Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) provide an unlimited cell source to treat cardiovascular diseases, the leading cause of death worldwide. However, current hiPSC-CMs retain an immature phenotype that leads to difficulties for integration with adult myocardium after transplantation. To address this, we recently utilized electrically conductive silicon nanowires (e-SiNWs) to facilitate self-assembly of hiPSC-CMs to form nanowired hiPSC cardiac spheroids. Our previous results showed addition of e-SiNWs effectively enhanced the functions of the cardiac spheroids and improved the cellular maturation of hiPSC-CMs. Here, we examined two important factors that can affect functions of the nanowired hiPSC cardiac spheroids: (1) cell number per spheroid (i.e., size of the spheroids), and (2) the electrical conductivity of the e-SiNWs. To examine the first factor, we prepared hiPSC cardiac spheroids with four different sizes by varying cell number per spheroid (∼0.5k, ∼1k, ∼3k, ∼7k cells/spheroid). Spheroids with ∼3k cells/spheroid was found to maximize the beneficial effects of the 3D spheroid microenvironment. This result was explained with a semi-quantitative theory that considers two competing factors: 1) the improved 3D cell-cell adhesion, and 2) the reduced oxygen supply to the center of spheroids with the increase of cell number. Also, the critical role of electrical conductivity of silicon nanowires has been confirmed in improving tissue function of hiPSC cardiac spheroids. These results lay down a solid foundation to develop suitable nanowired hiPSC cardiac spheroids as an innovative cell delivery system to treat cardiovascular diseases. Cardiovascular disease is the leading cause of death and disability worldwide. Due to the limited regenerative capacity of adult human hearts, human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have received significant attention because they provide a patient specific

  20. Modeling tissue contamination to improve molecular identification of the primary tumor site of metastases

    DEFF Research Database (Denmark)

    Vincent, Martin; Perell, Katharina; Nielsen, Finn Cilius

    2014-01-01

    with any predictor model. The usability of the model is illustrated on primary tumor site identification of liver biopsies, specifically, on a human dataset consisting of microRNA expression measurements of primary tumor samples, benign liver samples and liver metastases. For a predictor trained on primary...... tumor and benign liver samples, the contamination model decreased the test error on biopsies from liver metastases from 77 to 45%. A further reduction to 34% was obtained by including biopsies in the training data....

  1. Coupled Hybrid Continuum-Discrete Model of Tumor Angiogenesis and Growth.

    Directory of Open Access Journals (Sweden)

    Jie Lyu

    Full Text Available The processes governing tumor growth and angiogenesis are codependent. To study the relationship between them, we proposed a coupled hybrid continuum-discrete model. In this model, tumor cells, their microenvironment (extracellular matrixes, matrix-degrading enzymes, and tumor angiogenic factors, and their network of blood vessels, described by a series of discrete points, were considered. The results of numerical simulation reveal the process of tumor growth and the change in microenvironment from avascular to vascular stage, indicating that the network of blood vessels develops gradually as the tumor grows. Our findings also reveal that a tumor is divided into three regions: necrotic, semi-necrotic, and well-vascularized. The results agree well with the previous relevant studies and physiological facts, and this model represents a platform for further investigations of tumor therapy.

  2. Tumor microenvironmental changes induced by the sulfamate carbonic anhydrase IX inhibitor S4 in a laryngeal tumor model.

    Directory of Open Access Journals (Sweden)

    Tineke W H Meijer

    Full Text Available BACKGROUND AND PURPOSE: Carbonic anhydrase IX (CAIX plays a pivotal role in pH homeostasis, which is essential for tumor cell survival. We examined the effect of the CAIX inhibitor 4-(3'(3",5"-dimethylphenyl-ureidophenyl sulfamate (S4 on the tumor microenvironment in a laryngeal tumor model by analyzing proliferation, apoptosis, necrosis, hypoxia, metabolism and CAIX ectodomain shedding. METHODS: SCCNij202 tumor bearing-mice were treated with S4 for 1, 3 or 5 days. CAIX ectodomain shedding was measured in the serum after therapy. Effects on tumor cell proliferation, apoptosis, necrosis, hypoxia (pimonidazole and CAIX were investigated with quantitative immunohistochemistry. Metabolic transporters and enzymes were quantified with qPCR. RESULTS: CAIX ectodomain shedding decreased after treatment with S4 (p<0.01. S4 therapy did neither influence tumor cell proliferation nor the amount of apoptosis and necrosis. Hypoxia (pimonidazole and CAIX expression were also not affected by S4. CHOP and MMP9 mRNA as a reference of intracellular pH did not change upon treatment with S4. Compensatory mechanisms of pH homeostasis at the mRNA level were not observed. CONCLUSION: As the clinical and biological meaning of the decrease in CAIX ectodomain shedding after S4 therapy is not clear, studies are required to elucidate whether the CAIX ectodomain has a paracrine or autocrine signaling function in cancer biology. S4 did not influence the amount of proliferation, apoptosis, necrosis and hypoxia. Therefore, it is unlikely that S4 can be used as single agent to influence tumor cell kill and proliferation, and to target primary tumor growth.

  3. In vitro tumor models: advantages, disadvantages, variables, and selecting the right platform

    Directory of Open Access Journals (Sweden)

    Moriah eKatt

    2016-02-01

    Full Text Available In vitro tumor models have provided important tools for cancer research and serve as low-cost screening platforms for drug therapies; however, cancer recurrence remains largely unchecked due to metastasis, which is the cause of the majority of cancer related deaths. The need for an improved understanding of the progression and treatment of cancer has pushed for increased accuracy and physiological relevance of in vitro tumor models. As a result, in vitro tumor models have concurrently increased in complexity and their output parameters further diversified, since these models have progressed beyond simple proliferation, invasion, and cytotoxicity screens and have begun recapitulating critical steps in the metastatic cascade, such as intravasation, extravasation, angiogenesis, matrix remodeling, and tumor cell dormancy. Advances in tumor cell biology, 3D cell culture, tissue engineering, biomaterials, microfabrication, and microfluidics have enabled rapid development of new in vitro tumor models that often incorporate multiple cell types, extracellular matrix materials, and spatial and temporal introduction of soluble factors. Other innovations include the incorporation of perfusable microvessels to simulate the tumor vasculature and model intravasation and extravasation. The drive towards precision medicine has increased interest in adapting in vitro tumor models for patient-specific therapies, clinical management, and assessment of metastatic potential. Here, we review the wide range of current in vitro tumor models and summarize their advantages, disadvantages, and suitability in modeling specific aspects of the metastatic cascade and drug treatment.

  4. The Use of Porous Scaffold as a Tumor Model

    Directory of Open Access Journals (Sweden)

    Mei Zhang

    2013-01-01

    Full Text Available Background. Human cancer is a three-dimensional (3D structure consisting of neighboring cells, extracellular matrix, and blood vessels. It is therefore critical to mimic the cancer cells and their surrounding environment during in vitro study. Our aim was to establish a 3D cancer model using a synthetic composite scaffold. Methods. High-density low-volume seeding was used to promote attachment of a non-small-cell lung cancer cell line (NCI-H460 to scaffolds. Growth patterns in 3D culture were compared with those of monolayers. Immunohistochemistry was conducted to compare the expression of Ki67, CD44, and carbonic anhydrase IX. Results. NCI-H460 readily attached to the scaffold without surface pretreatment at a rate of 35% from a load of 1.5 × 106 cells. Most cells grew vertically to form clumps along the surface of the scaffold, and cell morphology resembled tissue origin; 2D cultures exhibited characteristics of adherent epithelial cancer cell lines. Expression patterns of Ki67, CD44, and CA IX varied markedly between 3D and monolayer cultures. Conclusions. The behavior of cancer cells in our 3D model is similar to tumor growth in vivo. This model will provide the basis for future study using 3D cancer culture.

  5. Combination of PDT and a DNA demethylating agent produces anti-tumor immune response in a mouse tumor model

    Science.gov (United States)

    Mroz, Pawel; Hamblin, Michael R.

    2009-06-01

    Epigenetic mechanisms, which involve DNA methylation and histone modifications, result in the heritable silencing of genes without a change in their coding sequence. However, these changes must be actively maintained after each cell division rendering them a promising target for pharmacologic inhibition. DNA methyltransferase inhibitors like 5-aza-deoxycytidine (5-aza-dC) induce and/or up-regulate the expression of MAGE-type antigens in human and mice cancer cells. Photodynamic therapy (PDT) has been shown to be an effective locally ablative anti-cancer treatment that has the additional advantage of stimulating tumor-directed immune response. We studied the effects of a new therapy that combined the demethylating agent 5-aza-dC with PDT in the breast cancer model 4T1 syngenic to immunocompetent BALB/c mice. PDT was used as a locally ablating tumor treatment that is capable of eliciting strong and tumor directed immune response while 5-aza-dC pretreatment was used promote de novo induction of the expression of P1A.protein. This is the mouse homolog of human MAGE family antigens and is reported to function as a tumor rejection antigen in certain mouse tumors. This strategy led to an increase in PDT-mediated immune response and better treatment outcome. These results strongly suggest that the MAGE family antigens are important target for PDT mediated immune response but that their expression can be silenced by epigenetic mechanisms. Therefore the possibility that PDT can be combined with epigenetic strategies to elicit anti-tumor immunity in MAGE-positive tumor models is highly clinically significant and should be studied in detail.

  6. Two Dimensional Mathematical Model of Tumor Angiogenesis: Coupling of Avascular Growth and Vascularization

    Directory of Open Access Journals (Sweden)

    Farideh Hosseini

    2015-09-01

    Full Text Available Introduction As a tumor grows, the demand for oxygen and nutrients increases and it grows further if acquires the ability to induce angiogenesis. In this study, we aimed to present a two-dimensional continuous mathematical model for avascular tumor growth, coupled with a discrete model of angiogenesis. Materials and Methods In the avascular growth model, tumor is considered as a single mass, which uptakes oxygen through diffusion and invades the extracellular matrix (ECM. After the tumor reaches its maximum size in the avascular growth phase, tumor cells may be in three different states (proliferative, quiescent and apoptotic, depending on oxygen availability. Quiescent cells are assumed to secrete tumor angiogenic factors, which diffuse into the surrounding tissue until reaching endothelial cells. The mathematical model for tumor angiogenesis is consisted of a five-point finite difference scheme to simulate the progression of endothelial cells in ECM and their penetration into the tumor. Results The morphology of produced networks was investigated, based on various ECM degradation patterns. The generated capillary networks involved the rules of microvascular branching and anastomosis. Model predictions were in qualitative agreement with experimental observations and might have implications as a supplementary model to facilitate mathematical analyses for anti-cancer therapies. Conclusion Our numerical simulations could facilitate the qualitative comparison between three layers of tumor cells, their TAF-producing abilities and subsequent penetration of micro-vessels in order to determine the dynamics of microvascular branching and anastomosis in ECM and three different parts of the tumor.

  7. A voxel-based multiscale model to simulate the radiation response of hypoxic tumors.

    Science.gov (United States)

    Espinoza, I; Peschke, P; Karger, C P

    2015-01-01

    In radiotherapy, it is important to predict the response of tumors to irradiation prior to the treatment. This is especially important for hypoxic tumors, which are known to be highly radioresistant. Mathematical modeling based on the dose distribution, biological parameters, and medical images may help to improve this prediction and to optimize the treatment plan. A voxel-based multiscale tumor response model for simulating the radiation response of hypoxic tumors was developed. It considers viable and dead tumor cells, capillary and normal cells, as well as the most relevant biological processes such as (i) proliferation of tumor cells, (ii) hypoxia-induced angiogenesis, (iii) spatial exchange of cells leading to tumor growth, (iv) oxygen-dependent cell survival after irradiation, (v) resorption of dead cells, and (vi) spatial exchange of cells leading to tumor shrinkage. Oxygenation is described on a microscopic scale using a previously published tumor oxygenation model, which calculates the oxygen distribution for each voxel using the vascular fraction as the most important input parameter. To demonstrate the capabilities of the model, the dependence of the oxygen distribution on tumor growth and radiation-induced shrinkage is investigated. In addition, the impact of three different reoxygenation processes is compared and tumor control probability (TCP) curves for a squamous cells carcinoma of the head and neck (HNSSC) are simulated under normoxic and hypoxic conditions. The model describes the spatiotemporal behavior of the tumor on three different scales: (i) on the macroscopic scale, it describes tumor growth and shrinkage during radiation treatment, (ii) on a mesoscopic scale, it provides the cell density and vascular fraction for each voxel, and (iii) on the microscopic scale, the oxygen distribution may be obtained in terms of oxygen histograms. With increasing tumor size, the simulated tumors develop a hypoxic core. Within the model, tumor shrinkage was

  8. Halofuginone Inhibits Angiogenesis and Growth in Implanted Metastatic Rat Brain Tumor Model-an MRI Study

    Directory of Open Access Journals (Sweden)

    Rinat Abramovitch

    2004-09-01

    Full Text Available Tumor growth and metastasis depend on angiogenesis; therefore, efforts are made to develop specific angiogenic inhibitors. Halofuginone (HF is a potent inhibitor of collagen type α1(I. In solid tumor models, HF has a potent antitumor and antiangiogenic effect in vivo, but its effect on brain tumors has not yet been evaluated. By employing magnetic resonance imaging (MRI, we monitored the effect of HF on tumor progression and vascularization by utilizing an implanted malignant fibrous histiocytoma metastatic rat brain tumor model. Here we demonstrate that treatment with HF effectively and dose-dependently reduced tumor growth and angiogenesis. On day 13, HF-treated tumors were fivefold smaller than control (P < .001. Treatment with HF significantly prolonged survival of treated animals (142%; P = .001. In HF-treated rats, tumor vascularization was inhibited by 30% on day 13 and by 37% on day 19 (P < .05. Additionally, HF treatment inhibited vessel maturation (P = .03. Finally, in HF-treated rats, we noticed the appearance of a few clusters of satellite tumors, which were distinct from the primary tumor and usually contained vessel cores. This phenomenon was relatively moderate when compared to previous reports of other antiangiogenic agents used to treat brain tumors. We therefore conclude that HF is effective for treatment of metastatic brain tumors.

  9. Fluid absorption related to ion transport in human airway epithelial spheroids

    DEFF Research Database (Denmark)

    Pedersen, P S; Holstein-Rathlou, N H; Larsen, P L

    1999-01-01

    in non-CF than in CF spheroids, 3) Cl(-)-channel inhibitors increased fluid absorption in amiloride-treated non-CF spheroids to a level equal to that of amiloride-treated CF spheroids, 4) hydrochlorothiazide reduced the amiloride-insensitive fluid absorption in both non-CF and CF spheroids, and 5...

  10. Unique Boron Carbide Nanoparticle Nanobio Interface: Effects on Protein-RNA Interactions and 3-D Spheroid Metastatic Phenotype.

    Science.gov (United States)

    Delong, Robert K; Hurst, Miranda N; Aryal, Santosh; Inchun, Nantipoor K

    2016-05-01

    The effect of boron carbide (B4C) nanoparticles (NP) on protein-RNA complexes and metastatic phenotype of 3-D tumor spheroids was investigated. Characterization was performed by transmission electron microscopy (TEM), zeta potential (ZP), 2-dimensional fluorescence difference spectroscopy (2-D FDS), gel electrophoresis, MTT, haemolysis and 3-D tumor spheroid assays. TEM showed NP were homogenous (≤50 nm) and spherical in shape. Zeta potential (ζ) of NP (-43.3) shifted upon protein:RNA interaction (+26.9). Protein:RNA complex interaction with NP was confirmed by 2-D FDS, demonstrating excitation/emission blue shift and lowered fluorescence intensity, and electrophoretic mobility shift assay (EMSA), where presence of B4C ablated visualization of the complex. B4C NP cytotoxicity was less than zinc oxide by MTT assay, protected haemolysis and effected 3-D tumor spheroid metastatic phenotype. Nanobio interface of B4C nanoparticles is unique and its anticancer potential may be mediated by altering protein and RNA interactions. Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  11. Electron, proton, neutron as spheroidical particles

    International Nuclear Information System (INIS)

    Bagge, E.R.

    1993-01-01

    It is shown that it is possible to describe the electron and the proton at rest within the framework of Dirac's relativistic theory of particles as electro-magnetic stable, spheroidal particles like balloons with very thin envelopes. Their properties, especially their spins and their magnetic momenta, are exactly those, which have been measured at first and later on derived by Dirac. In this picture the neutron plays the role of a system of two concentric and synchronically rotating balloons with a small distance between them at a positive energetic minimum of balance at 1.26 MeV. The magnetic moment of this particle has a negative sign and is of the correct size. (orig.)

  12. Effect of Irradiation on Tumor Microenvironment and Bone Marrow Cell Migration in a Preclinical Tumor Model

    Energy Technology Data Exchange (ETDEWEB)

    Kane, Jonathan L. [Department of Biological Sciences, Oakland University, Rochester, Michigan (United States); Department of Radiation Oncology, William Beaumont Health System, Royal Oak, Michigan (United States); Krueger, Sarah A.; Hanna, Alaa [Department of Radiation Oncology, William Beaumont Health System, Royal Oak, Michigan (United States); Raffel, Thomas R. [Department of Biological Sciences, Oakland University, Rochester, Michigan (United States); Wilson, George D. [Department of Radiation Oncology, William Beaumont Health System, Royal Oak, Michigan (United States); Madlambayan, Gerard J. [Department of Biological Sciences, Oakland University, Rochester, Michigan (United States); Marples, Brian, E-mail: Brian.Marples@beaumont.edu [Department of Radiation Oncology, William Beaumont Health System, Royal Oak, Michigan (United States)

    2016-09-01

    Purpose: To characterize the tumor microenvironment after standard radiation therapy (SRT) and pulsed radiation therapy (PRT) in Lewis lung carcinoma (LLC) allografts. Methods and Materials: Subcutaneous LLC tumors were established in C57BL/6 mice. Standard RT or PRT was given at 2 Gy/d for a total dose of 20 Gy using a 5 days on, 2 days off schedule to mimic clinical delivery. Radiation-induced tumor microenvironment changes were examined after treatment using flow cytometry and antibody-specific histopathology. Normal tissue effects were measured using noninvasive {sup 18}F-fluorodeoxyglucose positron emission tomography/computed tomography after naïve animals were given whole-lung irradiation to 40 Gy in 4 weeks using the same 2-Gy/d regimens. Results: Over the 2 weeks of therapy, PRT was more effective than SRT at reducing tumor growth rate (0.31 ± 0.02 mm{sup 3}/d and 0.55 ± 0.04 mm{sup 3}/d, respectively; P<.007). Histopathology showed a significant comparative reduction in the levels of Ki-67 (14.5% ± 3%), hypoxia (10% ± 3.5%), vascular endothelial growth factor (2.3% ± 1%), and stromal-derived factor-1α (2.5% ± 1.4%), as well as a concomitant decrease in CD45{sup +} bone marrow–derived cell (BMDC) migration (7.8% ± 2.2%) after PRT. The addition of AMD3100 also decreased CD45{sup +} BMDC migration in treated tumors (0.6% ± 0.1%). Higher vessel density was observed in treated tumors. No differences were observed in normal lung tissue after PRT or SRT. Conclusions: Pulsed RT–treated tumors exhibited slower growth and reduced hypoxia. Pulsed RT eliminated initiation of supportive mechanisms utilized by tumors in low oxygen microenvironments, including angiogenesis and recruitment of BMDCs.

  13. Mitigating Errors in External Respiratory Surrogate-Based Models of Tumor Position

    International Nuclear Information System (INIS)

    Malinowski, Kathleen T.; McAvoy, Thomas J.; George, Rohini; Dieterich, Sonja; D'Souza, Warren D.

    2012-01-01

    Purpose: To investigate the effect of tumor site, measurement precision, tumor–surrogate correlation, training data selection, model design, and interpatient and interfraction variations on the accuracy of external marker-based models of tumor position. Methods and Materials: Cyberknife Synchrony system log files comprising synchronously acquired positions of external markers and the tumor from 167 treatment fractions were analyzed. The accuracy of Synchrony, ordinary-least-squares regression, and partial-least-squares regression models for predicting the tumor position from the external markers was evaluated. The quantity and timing of the data used to build the predictive model were varied. The effects of tumor–surrogate correlation and the precision in both the tumor and the external surrogate position measurements were explored by adding noise to the data. Results: The tumor position prediction errors increased during the duration of a fraction. Increasing the training data quantities did not always lead to more accurate models. Adding uncorrelated noise to the external marker-based inputs degraded the tumor–surrogate correlation models by 16% for partial-least-squares and 57% for ordinary-least-squares. External marker and tumor position measurement errors led to tumor position prediction changes 0.3–3.6 times the magnitude of the measurement errors, varying widely with model algorithm. The tumor position prediction errors were significantly associated with the patient index but not with the fraction index or tumor site. Partial-least-squares was as accurate as Synchrony and more accurate than ordinary-least-squares. Conclusions: The accuracy of surrogate-based inferential models of tumor position was affected by all the investigated factors, except for the tumor site and fraction index.

  14. Mesenchymal stem cells support growth and organization of host-liver colorectal-tumor organoids and possibly resistance to chemotherapy.

    Science.gov (United States)

    Devarasetty, Mahesh; Wang, Edina; Soker, Shay; Skardal, Aleksander

    2017-06-07

    Despite having yielded extensive breakthroughs in cancer research, traditional 2D cell cultures have limitations in studying cancer progression and metastasis and screening therapeutic candidates. 3D systems can allow cells to grow, migrate, and interact with each other and the surrounding matrix, resulting in more realistic constructs. Furthermore, interactions between host tissue and developing tumors influence the susceptibility of tumors to drug treatments. Host-liver colorectal-tumor spheroids composed of primary human hepatocytes, mesenchymal stem cells (MSC) and colon carcinoma HCT116 cells were created in simulated microgravity rotating wall vessel (RWV) bioreactors. The cells were seeded on hyaluronic acid-based microcarriers, loaded with liver-specific growth factors and ECM components. Only in the presence of MSC, large tumor foci rapidly formed inside the spheroids and increased in size steadily over time, while not greatly impacting albumin secretion from hepatocytes. The presence of MSC appeared to drive self-organization and formation of a stroma-like tissue surrounding the tumor foci and hepatocytes. Exposure to a commonly used chemotherapeutic 5-FU showed a dose-dependent cytotoxicity. However, if tumor organoids were allowed to mature in the RWV, they were less sensitive to the drug treatment. These data demonstrate the potential utility of liver tumor organoids for cancer progression and drug response modeling.

  15. Structural Transition in a Fluid of Spheroids: A Low-Density Vestige of Jamming.

    Science.gov (United States)

    Cohen, A P; Dorosz, S; Schofield, A B; Schilling, T; Sloutskin, E

    2016-03-04

    A thermodynamically equilibrated fluid of hard spheroids is a simple model of liquid matter. In this model, the coupling between the rotational degrees of freedom of the constituent particles and their translations may be switched off by a continuous deformation of a spheroid of aspect ratio t into a sphere (t=1). We demonstrate, by experiments, theory, and computer simulations, that dramatic nonanalytic changes in structure and thermodynamics of the fluids take place, as the coupling between rotations and translations is made to vanish. This nonanalyticity, reminiscent of a second-order liquid-liquid phase transition, is not a trivial consequence of the shape of an individual particle. Rather, free volume considerations relate the observed transition to a similar nonanalyticity at t=1 in structural properties of jammed granular ellipsoids. This observation suggests a deep connection to exist between the physics of jamming and the thermodynamics of simple fluids.

  16. Steroid Tumor Environment in Male and Female Mice Model of Canine and Human Inflammatory Breast Cancer

    Directory of Open Access Journals (Sweden)

    Sara Caceres

    2016-01-01

    Full Text Available Canine inflammatory mammary cancer (IMC shares clinical and histopathological characteristics with human inflammatory breast cancer (IBC and has been proposed as a good model for studying the human disease. The aim of this study was to evaluate the capacity of female and male mice to reproduce IMC and IBC tumors and identify the hormonal tumor environment. To perform the study sixty 6–8-week-old male and female mice were inoculated subcutaneously with a suspension of 106 IPC-366 and SUM149 cells. Tumors and serum were collected and used for hormonal analysis. Results revealed that IPC-366 reproduced tumors in 90% of males inoculated after 2 weeks compared with 100% of females that reproduced tumor at the same time. SUM149 reproduced tumors in 40% of males instead of 80% of females that reproduced tumors after 4 weeks. Both cell lines produce distant metastasis in lungs being higher than the metastatic rates in females. EIA analysis revealed that male tumors had higher T and SO4E1 concentrations compared to female tumors. Serum steroid levels were lower than those found in tumors. In conclusion, IBC and IMC male mouse model is useful as a tool for IBC research and those circulating estrogens and intratumoral hormonal levels are crucial in the development and progression of tumors.

  17. An artificial blood vessel implanted three-dimensional microsystem for modeling transvascular migration of tumor cells.

    Science.gov (United States)

    Wang, Xue-Ying; Pei, Ying; Xie, Min; Jin, Zi-He; Xiao, Ya-Shi; Wang, Yang; Zhang, Li-Na; Li, Yan; Huang, Wei-Hua

    2015-02-21

    Reproducing a tumor microenvironment consisting of blood vessels and tumor cells for modeling tumor invasion in vitro is particularly challenging. Here, we report an artificial blood vessel implanted 3D microfluidic system for reproducing transvascular migration of tumor cells. The transparent, porous and elastic artificial blood vessels are obtained by constructing polysaccharide cellulose-based microtubes using a chitosan sacrificial template, and possess excellent cytocompatibility, permeability, and mechanical characteristics. The artificial blood vessels are then fully implanted into the collagen matrix to reconstruct the 3D microsystem for modeling transvascular migration of tumor cells. Well-defined simulated vascular lumens were obtained by proliferation of the human umbilical vein endothelial cells (HUVECs) lining the artificial blood vessels, which enables us to reproduce structures and functions of blood vessels and replicate various hemodynamic parameters. Based on this model, the adhesion and transvascular migration of tumor cells across the artificial blood vessel have been well reproduced.

  18. Modeling the Interplay Between Tumor Volume Regression and Oxygenation in Uterine Cervical Cancer During Radiotherapy Treatment.

    Science.gov (United States)

    Belfatto, Antonella; Riboldi, Marco; Ciardo, Delia; Cattani, Federica; Cecconi, Agnese; Lazzari, Roberta; Jereczek-Fossa, Barbara Alicja; Orecchia, Roberto; Baroni, Guido; Cerveri, Pietro

    2016-03-01

    This paper describes a patient-specific mathematical model to predict the evolution of uterine cervical tumors at a macroscopic scale, during fractionated external radiotherapy. The model provides estimates of tumor regrowth and dead-cell reabsorption, incorporating the interplay between tumor regression rate and radiosensitivity, as a function of the tumor oxygenation level. Model parameters were estimated by minimizing the difference between predicted and measured tumor volumes, these latter being obtained from a set of 154 serial cone-beam computed tomography scans acquired on 16 patients along the course of the therapy. The model stratified patients according to two different estimated dynamics of dead-cell removal and to the predicted initial value of the tumor oxygenation. The comparison with a simpler model demonstrated an improvement in fitting properties of this approach (fitting error average value <5%, p < 0.01), especially in case of tumor late responses, which can hardly be handled by models entailing a constant radiosensitivity, failing to model changes from initial severe hypoxia to aerobic conditions during the treatment course. The model predictive capabilities suggest the need of clustering patients accounting for cancer cell line, tumor staging, as well as microenvironment conditions (e.g., oxygenation level).

  19. Differentiating between borderline and invasive malignancies in ovarian tumors using a multivariate logistic regression model

    Directory of Open Access Journals (Sweden)

    Jiabin Chen

    2015-08-01

    Conclusion: Differentiation between borderline and invasive ovarian tumors can be achieved using a model based on the following criteria: menopausal status; cancer antigen 125 level; and ultrasound parameters. The model is helpful to oncologists and patients in the initial evaluation phase of ovarian tumors.

  20. Analysis of Gene Expression in 3D Spheroids Highlights a Survival Role for ASS1 in Mesothelioma

    Science.gov (United States)

    Barbone, Dario; Van Dam, Loes; Follo, Carlo; Jithesh, Puthen V.; Zhang, Shu-Dong; Richards, William G.; Bueno, Raphael; Fennell, Dean A.; Broaddus, V. Courtney

    2016-01-01

    To investigate the underlying causes of chemoresistance in malignant pleural mesothelioma, we have studied mesothelioma cell lines as 3D spheroids, which acquire increased chemoresistance compared to 2D monolayers. We asked whether the gene expression of 3D spheroids would reveal mechanisms of resistance. To address this, we measured gene expression of three mesothelioma cell lines, M28, REN and VAMT, grown as 2D monolayers and 3D spheroids. A total of 209 genes were differentially expressed in common by the three cell lines in 3D (138 upregulated and 71 downregulated), although a clear resistance pathway was not apparent. We then compared the list of 3D genes with two publicly available datasets of gene expression of 56 pleural mesotheliomas compared to normal tissues. Interestingly, only three genes were increased in both 3D spheroids and human tumors: argininosuccinate synthase 1 (ASS1), annexin A4 (ANXA4) and major vault protein (MVP); of these, ASS1 was the only consistently upregulated of the three genes by qRT-PCR. To measure ASS1 protein expression, we stained 2 sets of tissue microarrays (TMA): one with 88 pleural mesothelioma samples and the other with additional 88 pleural mesotheliomas paired with matched normal tissues. Of the 176 tumors represented on the two TMAs, ASS1 was expressed in 87 (50%; staining greater than 1 up to 3+). For the paired samples, ASS1 expression in mesothelioma was significantly greater than in the normal tissues. Reduction of ASS1 expression by siRNA significantly sensitized mesothelioma spheroids to the pro-apoptotic effects of bortezomib and of cisplatin plus pemetrexed. Although mesothelioma is considered by many to be an ASS1-deficient tumor, our results show that ASS1 is elevated at the mRNA and protein levels in mesothelioma 3D spheroids and in human pleural mesotheliomas. We also have uncovered a survival role for ASS1, which may be amenable to targeting to undermine mesothelioma multicellular resistance. PMID:26982031

  1. Effect of transarterial pulsed perfusion with heated saline on tumor vascular permeability in a rabbit VX2 liver tumor model

    International Nuclear Information System (INIS)

    Cao Wei; Li Jinghua; Feng Dayun; Wan Yi; Liu Yufeng; Yang Qingfeng; Cheng Jianwei; Zhao Siyuan; Zhang Hongxin

    2012-01-01

    Purpose: To evaluate the effect of transarterial pulsed perfusion with 60 °C saline on vascular permeability of tumor tissue, as well as its hepatic and renal toxicity, in a rabbit VX2 liver model. Materials and methods: VX2 carcinomas were grown in rabbit livers, forty male New Zealand white tumor-bearing rabbits were randomly divided into four groups, followed by transarterial perfusion with 37 °C saline 60 ml (n = 10) (control 1 group), transarterial pulsed perfusion with 37 °C saline 60 ml (n = 10) (control 2 group), transarterial continuous perfusion with 60 °C saline 60 ml (n = 10) (TCP group), transarterial pulsed perfusion with 60 °C saline 60 ml (n = 10) (TPP group), the duration of time for tumor tissues in the range 43–45 °C of the treated groups was measured with needle thermometer during perfusion. Vascular permeability was assessed using the extravasation of Evans blue (EB) dye in the tumor or normal liver tissues of the four groups separately, the tumor or normal liver tissues of the four groups were estimated by histopathologic examination, and hepatic and renal toxicity was evaluated by means of blood biochemical analysis. The vascular endothelial cells in the tumor were observed by transmission electron microscopy (TEM). Results: The duration of time for tumor tissues in the range 43–45 °C of TPP group showed significantly longer than that of TCP group (12.3 ± 3.3 min vs. 5.7 ± 2.5 min) (P 0.05), and there was no significant difference in the serum BUN, Cr levels among the four groups at 1, 2, 4, 8, 24 h after perfusion. Observed by hematoxylin and eosin staining, there were no obvious signs of tissue destruction in liver tissue and tumor tissue. TEM indicating the endothelial cell gap was broadened and the endothelial cells’ microvillus was decreased after heated perfusion. Conclusions: The vascular permeability of the rabbit VX2 tumor was significantly increased after transarterial pulsed perfusion with 60 °C saline without

  2. Application of the sextic oscillator potential together with Mathieu and spheroidal functions for triaxial and X(5 type nuclei

    Directory of Open Access Journals (Sweden)

    Raduta A. A.

    2014-03-01

    Full Text Available The Bohr-Mottelson Hamiltonian is amended with a potential which depends on both β and γ deformation variables and which allows us to separate the β variable from the other variables. The equation for the β variable is quasi-exactly solved for a sextic oscillator with centrifugal barrier potential. Concerning the γ equation, its solutions are the angular spheroidal and Mathieu functions for X(5 type and triaxial nuclei, respectively. The models developed in this way are conventionally called the Sextic and Spheroidal Approach (SSA and the Sextic and Mathieu Approach (SMA. SSA and SMA was successfully applied for several nuclei, details being presented below.

  3. 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.

  4. Modulation of Huh7.5 spheroid formation and functionality using modified PEG-based hydrogels of different stiffness.

    Directory of Open Access Journals (Sweden)

    Bae Hoon Lee

    Full Text Available Physical cues, such as cell microenvironment stiffness, are known to be important factors in modulating cellular behaviors such as differentiation, viability, and proliferation. Apart from being able to trigger these effects, mechanical stiffness tuning is a very convenient approach that could be implemented readily into smart scaffold designs. In this study, fibrinogen-modified poly(ethylene glycol-diacrylate (PEG-DA based hydrogels with tunable mechanical properties were synthesized and applied to control the spheroid formation and liver-like function of encapsulated Huh7.5 cells in an engineered, three-dimensional liver tissue model. By controlling hydrogel stiffness (0.1-6 kPa as a cue for mechanotransduction representing different stiffness of a normal liver and a diseased cirrhotic liver, spheroids ranging from 50 to 200 μm were formed over a three week time-span. Hydrogels with better compliance (i.e. lower stiffness promoted formation of larger spheroids. The highest rates of cell proliferation, albumin secretion, and CYP450 expression were all observed for spheroids in less stiff hydrogels like a normal liver in a healthy state. We also identified that the hydrogel modification by incorporation of PEGylated-fibrinogen within the hydrogel matrix enhanced cell survival and functionality possibly owing to more binding of autocrine fibronectin. Taken together, our findings establish guidelines to control the formation of Huh7.5 cell spheroids in modified PEGDA based hydrogels. These spheroids may serve as models for applications such as screening of pharmacological drug candidates.

  5. Chemical Evolution of Mn in Three Dwarf Spheroidal Galaxies Men ...

    Indian Academy of Sciences (India)

    ∗ & Jie Zhang1. 1Institute of ... for three local dwarf spheroidal galaxies (dSphs), considering the detailed. SNe yield and explosion rates for different .... progenitor are two degenerate white dwarfs. Acknowledgements. This work is supported ...

  6. Optimal definition of biological tumor volume using positron emission tomography in an animal model.

    Science.gov (United States)

    Wu, Ingrid; Wang, Hao; Huso, David; Wahl, Richard L

    2015-12-01

    The goal of the study is to investigate (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG-PET)'s ability to delineate the viable portion of a tumor in an animal model using cross-sectional histology as the validation standard. Syngeneic mammary tumors were grown in female Lewis rats. Macroscopic histological images of the transverse tumor sections were paired with their corresponding FDG micro-PET slices of the same cranial-caudal location to form 51 pairs of co-registered images. A binary classification system based on four FDG-PET tumor contouring methods was applied to each pair of images: threshold based on (1) percentage of maximum tumor voxel counts (Cmax), (2) percentage of tumor peak voxel counts (Cpeak), (3) multiples of liver mean voxel counts (Cliver) derived from PERCIST, and (4) an edge-detection-based automated contouring system. The sensitivity, which represented the percentage of viable tumor areas correctly delineated by the gross tumor area (GTA) generated from a particular tumor contouring method, and the ratio (expressed in percentage) of the overestimated areas of a gross tumor area (GTAOE)/whole tumor areas on the macroscopic histology (WTAH), which represented how much a particular GTA extended into the normal structures surrounding the primary tumor target, were calculated. The receiver operating characteristic curves of all pairs of FDG-PET images have a mean area under the curve value of 0.934 (CI of 0.911-0.954), for representing how well each contouring method accurately delineated the viable tumor area. FDG-PET single value threshold tumor contouring based on 30 and 35 % of tumor Cmax or Cpeak and 6 × Cliver + 2 × SD achieved a sensitivity greater than 90 % with a GTAOE/WTAH ratio less than 10 %. Contouring based on 50 % of Cmax or Cpeak had a much lower sensitivity of 67.2-75.6 % with a GTAOE/WTAH ratio of 1.1-1.7 %. Automated edge detection was not reliable in this system. Single

  7. Model of avascular tumor growth and response to low dose exposure

    Science.gov (United States)

    Rodriguez Aguirre, J. M.; Custidiano, E. R.

    2011-12-01

    A single level cellular automata model is described and used to simulate early tumor growth, and the response of the tumor cells under low dose radiation affects. In this model the cell cycle of the population of normal and cancer cells is followed. The invasion mechanism of the tumor is simulated by a local factor that takes into account the microenvironment hardness to cell development, in a picture similar to the AMTIH model. The response of normal and cancer cells to direct effects of radiation is tested for various models and a model of bystander response is implemented.

  8. Model of avascular tumor growth and response to low dose exposure

    International Nuclear Information System (INIS)

    Rodriguez Aguirre, J M; Custidiano, E R

    2011-01-01

    A single level cellular automata model is described and used to simulate early tumor growth, and the response of the tumor cells under low dose radiation affects. In this model the cell cycle of the population of normal and cancer cells is followed. The invasion mechanism of the tumor is simulated by a local factor that takes into account the microenvironment hardness to cell development, in a picture similar to the AMTIH model. The response of normal and cancer cells to direct effects of radiation is tested for various models and a model of bystander response is implemented.

  9. Targeted Doxorubicin Delivery to Brain Tumors via Minicells: Proof of Principle Using Dogs with Spontaneously Occurring Tumors as a Model.

    Science.gov (United States)

    MacDiarmid, Jennifer A; Langova, Veronika; Bailey, Dale; Pattison, Scott T; Pattison, Stacey L; Christensen, Neil; Armstrong, Luke R; Brahmbhatt, Vatsala N; Smolarczyk, Katarzyna; Harrison, Matthew T; Costa, Marylia; Mugridge, Nancy B; Sedliarou, Ilya; Grimes, Nicholas A; Kiss, Debra L; Stillman, Bruce; Hann, Christine L; Gallia, Gary L; Graham, Robert M; Brahmbhatt, Himanshu

    2016-01-01

    Cytotoxic chemotherapy can be very effective for the treatment of cancer but toxicity on normal tissues often limits patient tolerance and often causes long-term adverse effects. The objective of this study was to assist in the preclinical development of using modified, non-living bacterially-derived minicells to deliver the potent chemotherapeutic doxorubicin via epidermal growth factor receptor (EGFR) targeting. Specifically, this study sought to evaluate the safety and efficacy of EGFR targeted, doxorubicin loaded minicells (designated EGFRminicellsDox) to deliver doxorubicin to spontaneous brain tumors in 17 companion dogs; a comparative oncology model of human brain cancers. EGFRminicellsDox were administered weekly via intravenous injection to 17 dogs with late-stage brain cancers. Biodistribution was assessed using single-photon emission computed tomography (SPECT) and magnetic resonance imaging (MRI). Anti-tumor response was determined using MRI, and blood samples were subject to toxicology (hematology, biochemistry) and inflammatory marker analysis. Targeted, doxorubicin-loaded minicells rapidly localized to the core of brain tumors. Complete resolution or marked tumor regression (>90% reduction in tumor volume) were observed in 23.53% of the cohort, with lasting anti-tumor responses characterized by remission in three dogs for more than two years. The median overall survival was 264 days (range 49 to 973). No adverse clinical, hematological or biochemical effects were observed with repeated administration of EGFRminicellsDox (30 to 98 doses administered in 10 of the 17 dogs). Targeted minicells loaded with doxorubicin were safely administered to dogs with late stage brain cancer and clinical activity was observed. These findings demonstrate the strong potential for clinical applications of targeted, doxorubicin-loaded minicells for the effective treatment of patients with brain cancer. On this basis, we have designed a Phase 1 clinical study of EGFR

  10. Targeted Doxorubicin Delivery to Brain Tumors via Minicells: Proof of Principle Using Dogs with Spontaneously Occurring Tumors as a Model.

    Directory of Open Access Journals (Sweden)

    Jennifer A MacDiarmid

    Full Text Available Cytotoxic chemotherapy can be very effective for the treatment of cancer but toxicity on normal tissues often limits patient tolerance and often causes long-term adverse effects. The objective of this study was to assist in the preclinical development of using modified, non-living bacterially-derived minicells to deliver the potent chemotherapeutic doxorubicin via epidermal growth factor receptor (EGFR targeting. Specifically, this study sought to evaluate the safety and efficacy of EGFR targeted, doxorubicin loaded minicells (designated EGFRminicellsDox to deliver doxorubicin to spontaneous brain tumors in 17 companion dogs; a comparative oncology model of human brain cancers.EGFRminicellsDox were administered weekly via intravenous injection to 17 dogs with late-stage brain cancers. Biodistribution was assessed using single-photon emission computed tomography (SPECT and magnetic resonance imaging (MRI. Anti-tumor response was determined using MRI, and blood samples were subject to toxicology (hematology, biochemistry and inflammatory marker analysis. Targeted, doxorubicin-loaded minicells rapidly localized to the core of brain tumors. Complete resolution or marked tumor regression (>90% reduction in tumor volume were observed in 23.53% of the cohort, with lasting anti-tumor responses characterized by remission in three dogs for more than two years. The median overall survival was 264 days (range 49 to 973. No adverse clinical, hematological or biochemical effects were observed with repeated administration of EGFRminicellsDox (30 to 98 doses administered in 10 of the 17 dogs.Targeted minicells loaded with doxorubicin were safely administered to dogs with late stage brain cancer and clinical activity was observed. These findings demonstrate the strong potential for clinical applications of targeted, doxorubicin-loaded minicells for the effective treatment of patients with brain cancer. On this basis, we have designed a Phase 1 clinical study of

  11. Multiresolution texture models for brain tumor segmentation in MRI.

    Science.gov (United States)

    Iftekharuddin, Khan M; Ahmed, Shaheen; Hossen, Jakir

    2011-01-01

    In this study we discuss different types of texture features such as Fractal Dimension (FD) and Multifractional Brownian Motion (mBm) for estimating random structures and varying appearance of brain tissues and tumors in magnetic resonance images (MRI). We use different selection techniques including KullBack - Leibler Divergence (KLD) for ranking different texture and intensity features. We then exploit graph cut, self organizing maps (SOM) and expectation maximization (EM) techniques to fuse selected features for brain tumors segmentation in multimodality T1, T2, and FLAIR MRI. We use different similarity metrics to evaluate quality and robustness of these selected features for tumor segmentation in MRI for real pediatric patients. We also demonstrate a non-patient-specific automated tumor prediction scheme by using improved AdaBoost classification based on these image features.

  12. Predictive models for lymph node metastases in patients with testicular germ cell tumors.

    Science.gov (United States)

    Mao, Yun; Hedgire, Sandeep; Prapruttam, Duangkamon; Harisinghani, Mukesh

    2015-10-01

    To develop predictive models for lymph node (LN) metastasis in testicular germ cell tumors. 291 patients with testicular germ cell tumors were included, which were divided into seminomatous and nonseminomatous groups. For screening the risk factors for LN metastasis, the tumor-related characteristics (including histopathological information and tumor markers) alpha fetoprotein and the lymph node-related features on CT were compared between metastatic cases and nonmetastatic cases. Two logistic regression models were built for each histological group, one depending on all tumor- and lymph node-related risk factors (Model 1) and another only on tumor-related factors (Model 2). Receivers operating characteristic curves were used to evaluate the predictive abilities of these models. 117 positive nodes/regions were identified in 68 patients, including 51 metastases and 17 occult metastases. Based on the selected independent risk factors, the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of Models 1 and 2 in seminomatous and nonseminomatous groups were (95.5%, 95.3%, 95.3%, 77.8%, and 99.2%), (63.6%, 83.6%, 80.7%, 40.0%, and 93.0%), (93.5%, 94.7%, 94.3%, 89.6%, and 96.8%), and (89.1%, 44.2%, 58.9%, 43.6%, and 89.4%), respectively. Two predictive models for each seminomatous and nonseminomatous testicular tumor were established based on lymph node- and tumor-related risk factors. In patients with tumor and lymph node-related risk factors, regular CT surveillance is likely sufficient for predicting LN status, while in the patients without any tumor and lymph node-related risk factors a long interval-time CT follow-up should be considered. Additionally, right side tumors tend to involve contralateral LNs compared to left side ones. Positive inguinal LNs more frequently occur in patients with a history of groin surgery.

  13. Simulating photoacoustic waves produced by individual biological particles with spheroidal wave functions

    Science.gov (United States)

    Li, Yong; Fang, Hui; Min, Changjun; Yuan, Xiaocong

    2015-10-01

    Under the usual approximation of treating a biological particle as a spheroidal droplet, we consider the analysis of its size and shape with the high frequency photoacoustics and develop a numerical method which can simulate its characteristic photoacoustic waves. This numerical method is based on the calculation of spheroidal wave functions, and when comparing to the finite element model (FEM) calculation, can reveal more physical information and can provide results independently at each spatial points. As the demonstration, red blood cells (RBCs) and MCF7 cell nuclei are studied, and their photoacoustic responses including field distribution, spectral amplitude, and pulse forming are calculated. We expect that integrating this numerical method with the high frequency photoacoustic measurement will form a new modality being extra to the light scattering method, for fast assessing the morphology of a biological particle.

  14. Referent 3D tumor model at cellular level in radionuclide therapy

    International Nuclear Information System (INIS)

    Spaic, R.; Ilic, R.D.; Petrovic, B.J.

    2002-01-01

    Aim Conventional internal dosimetry has a lot of limitations because of tumor dose nonuniformity. The best approach for absorbed dose at cellular level for different tumors in radionuclide therapy calculation is Monte Carlo method. The purpose of this study is to introduce referent tumor 3D model at cellular level for Monte Carlo simulation study in radionuclide therapy. Material and Methods The moment when tumor is detectable and when same therapy can start is time period in which referent 3D tumor model at cellular level was defined. In accordance with tumor growth rate at that moment he was a sphere with same radius (10 000 μm). In that tumor there are cells or cluster of cells, which are randomly distributed spheres. Distribution of cells/cluster of cells can be calculated from histology data but it was assumed that this distribution is normal with the same mean value and standard deviation (100±50 mm). Second parameter, which was selected to define referent tumor, is volume density of cells (30%). In this referent tumor there are no necroses. Stroma is defined as space between spheres with same concentration of materials as in spheres. Results: Referent tumor defined on this way have about 2,2 10 5 cells or cluster of cells random distributed. Using this referent 3D tumor model and for same concentration of radionuclides (1:100) and energy of beta emitters (1000 keV) which are homogeneously distributed in labeled cells absorbed dose for all cells was calculated. Simulations are done using FOTELP Monte Carlo code, which is modified for this purposes. Results of absorbed dose in cells are given in numerical values (1D distribution) and as the images (2D or 3D distributions). Conclusion Geometrical module for Monte Carlo simulation study can be standardized by introducing referent 3D tumor model at cellular level. This referent 3D tumor model gives most realistic presentation of different tumors at the moment of their detectability. Referent 3D tumor model at

  15. Biomimetic brain tumor niche regulates glioblastoma cells towards a cancer stem cell phenotype.

    Science.gov (United States)

    Liu, Yung-Chiang; Lee, I-Chi; Chen, Pin-Yuan

    2018-05-01

    Glioblastoma (GBM) is the most malignant primary brain tumor and contains tumorigenic cancer stem cells (CSCs), which support the progression of tumor growth. The selection of CSCs and facilitation of the brain tumor niches may assist the development of novel therapeutics for GBM. Herein, hydrogel materials composed of agarose and hydroxypropyl methyl cellulose (HMC) in different concentrations were established and compared to emulate brain tumor niches and CSC microenvironments within a label-free system. Human GBM cell line, U-87 MG, was cultured on a series of HMC-agarose based culture system. Cell aggregation and spheroids formation were investigated after 4 days of culture, and 2.5% HMC-agarose based culture system demonstrated the largest spheroids number and size. Moreover, CD133 marker expression of GBM cells after 6 days of culture in 2.5% HMC-agarose based culture system was 60%, relatively higher than the control group at only 15%. Additionally, cells on 2.5% HMC-agarose based culture system show the highest chemoresistance, even at the high dose of 500 µM temozolomide for 72 h, the live cell ratio was still > 80%. Furthermore, the results also indicate that the expression of ABCG2 gene was up-regulated after culture in 2.5% HMC-agarose based culture system. Therefore, our results demonstrated that biomimetic brain tumor microenvironment may regulate GBM cells towards the CSC phenotype and expression of CSC characteristics. The microenvironment selection and spheroids formation in HMC-agarose based culture system may provide a label-free CSC selection strategy and drug testing model for future biomedical applications.

  16. Molecular evolutionary analysis of a gender-limited MID ortholog from the homothallic species Volvox africanus with male and monoecious spheroids.

    Directory of Open Access Journals (Sweden)

    Kayoko Yamamoto

    Full Text Available Volvox is a very interesting oogamous organism that exhibits various types of sexuality and/or sexual spheroids depending upon species or strains. However, molecular bases of such sexual reproduction characteristics have not been studied in this genus. In the model species V. carteri, an ortholog of the minus mating type-determining or minus dominance gene (MID of isogamous Chlamydomonas reinhardtii is male-specific and determines the sperm formation. Male and female genders are genetically determined (heterothallism in V. carteri, whereas in several other species of Volvox both male and female gametes (sperm and eggs are formed within the same clonal culture (homothallism. To resolve the molecular basis of the evolution of Volvox species with monoecious spheroids, we here describe a MID ortholog in the homothallic species V. africanus that produces both monoecious and male spheroids within a single clonal culture. Comparison of synonymous and nonsynonymous nucleotide substitutions in MID genes between V. africanus and heterothallic volvocacean species suggests that the MID gene of V. africanus evolved under the same degree of functional constraint as those of the heterothallic species. Based on semi quantitative reverse transcription polymerase chain reaction analyses using the asexual, male and monoecious spheroids isolated from a sexually induced V. africanus culture, the MID mRNA level was significantly upregulated in the male spheroids, but suppressed in the monoecious spheroids. These results suggest that the monoecious spheroid-specific down regulation of gene expression of the MID homolog correlates with the formation of both eggs and sperm in the same spheroid in V. africanus.

  17. Increased Plasma Colloid Osmotic Pressure Facilitates the Uptake of Therapeutic Macromolecules in a Xenograft Tumor Model

    Directory of Open Access Journals (Sweden)

    Matthias Hofmann

    2009-08-01

    Full Text Available Elevated tumor interstitial fluid pressure (TIFP is a characteristic of most solid tumors. Clinically, TIFP may hamper the uptake of chemotherapeutic drugs into the tumor tissue reducing their therapeutic efficacy. In this study, a means of modulating TIFP to increase the flux of macromolecules into tumor tissue is presented, which is based on the rationale that elevated plasma colloid osmotic pressure (COP pulls water from tumor interstitium lowering the TIFP. Concentrated human serum albumin: (20% HSA, used as an agent to enhance COP, reduced the TIFP time-dependently from 8 to 2 mm Hg in human tumor xenograft models bearing A431 epidermoid vulva carcinomas. To evaluate whether this reduction facilitates the uptake of macromolecules, the intratumoral distribution of fluorescently conjugated dextrans (2.5 mg/ml and cetuximab (2.0 mg/ml was probed using novel time domain nearinfrared fluorescence imaging. This method permitted discrimination and semiquantification of tumor-accumulated conjugate from background and unspecific probe fluorescence. The coadministration of 20% HSA together with either dextrans or cetuximab was found to lower the TIFP significantly and increase the concentration of the substances within the tumor tissue in comparison to control tumors. Furthermore, combined administration of 20%HSA plus cetuximab reduced the tumor growth significantly in comparison to standard cetuximab treatment. These data demonstrate that increased COP lowers the TIFP within hours and increases the uptake of therapeutic macromolecules into the tumor interstitium leading to reduced tumor growth. This model represents a novel approach to facilitate the delivery of therapeutics into tumor tissue, particularly monoclonal antibodies.

  18. Effectivity of pazopanib treatment in orthotopic models of human testicular germ cell tumors

    International Nuclear Information System (INIS)

    Juliachs, Mercè; Viñals, Francesc; Vidal, August; Muro, Xavier Garcia del; Piulats, Josep M; Condom, Enric; Casanovas, Oriol; Graupera, Mariona; Germà, Jose R; Villanueva, Alberto

    2013-01-01

    Cisplatin (CDDP) resistance in testicular germ cell tumors (GCTs) is still a clinical challenge, and one associated with poor prognosis. The purpose of this work was to test pazopanib, an anti-tumoral and anti-angiogenic multikinase inhibitor, and its combination with lapatinib (an anti-ErbB inhibitor) in mouse orthotopic models of human testicular GCTs. We used two different models of human testicular GCTs orthotopically grown in nude mice; a CDDP-sensitive choriocarcinoma (TGT38) and a new orthotopic model generated from a metastatic GCT refractory to first-line CDDP chemotherapy (TGT44). Nude mice implanted with these orthotopic tumors were treated with the inhibitors and the effect on tumoral growth and angiogenesis was evaluated. TGT44 refractory tumor had an immunohistochemical profile similar to the original metastasis, with characteristics of yolk sac tumor. TGT44 did not respond when treated with cisplatin. In contrast, pazopanib had an anti-angiogenic effect and anti-tumor efficacy in this model. Pazopanib in combination with lapatinib in TGT38, an orthotopic model of choriocarcinoma had an additive effect blocking tumor growth. We present pazopanib as a possible agent for the alternative treatment of CDDP-sensitive and CDDP-refractory GCT patients, alone or in combination with anti-ErbB therapies

  19. Hypofractionated radiation induces a decrease in cell proliferation but no histological damage to organotypic multicellular spheroids of human glioblastomas

    NARCIS (Netherlands)

    Kaaijk, P.; Troost, D.; Sminia, P.; Hulshof, M. C.; van der Kracht, A. H.; Leenstra, S.; Bosch, D. A.

    1997-01-01

    The aim of this study was to examine the effect of radiation on glioblastoma, using an organotypic multicellular spheroid (OMS) model. Most glioblastoma cell lines are, in contrast to glioblastomas in vivo, relatively radiosensitive. This limits the value of using cell lines for studying the

  20. Cytolytic effects of autologous lymphokine-activated killer cells on organotypic multicellular spheroids of gliomas in vitro

    NARCIS (Netherlands)

    Kaaijk, P.; Troost, D.; Dast, P. K.; van den Berg, F.; Leenstra, S.; Bosch, D. A.

    1995-01-01

    Knowledge about lymphokine-activated killer (LAK) cell infiltration and LAK cell cytotoxicity is essential to improve the effectiveness of LAK cell therapy against gliomas. In the present study, organotypic multicellular spheroids (OMS) of glioma tissue were used as a culture model to study the

  1. Tumor affinity of radiolabeled peanut agglutinin compared with that of Ga-67 citrate in animal models

    International Nuclear Information System (INIS)

    Yokoyama, K.; Aburano, T.; Watanabe, N.; Kawabata, S.; Ishida, H.; Mukai, K.; Tonami, N.; Hisada, K.

    1985-01-01

    Peanut agglutinin (PNA) binds avidly to the immunodominant group of the tumor associated T antigen. The purpose of this study was to evaluate oncodiagnostic potential of radiolabeled PNA in animal models. PNA was labeled with I-125 or I-131 by Iodogen and also with In-111 by cyclic DTPA anhydride. The biological activity of PNA was examined by a hemaglutination titer with a photometer before and after labeling. Animal tumor models used were Lewis Lung Cancer(LLC), B-16 Melanotic Melanoma(MM), Yoshida Sarcoma(YS), Ehrlich Ascites Tumor(EAT and Hepatoma AH109A(HAH). Inflammatory tissue induced by turpentine oil was used as an abscess model. Serial scintigraphic images were obtained following IV injections of 100 μCi of I-131 or In-111-DTPA-PNA. The tumor affinity of Ga-67 citrate was studied to compare that of radiolabeled PNA. Tissue biodistribution was studied in EAT bearing mice. All of these tumor models except HAH were clearly visible by radiolabeled PNA without subtraction techniques. In the models of LLC and EAT, PNA showed the better accumulation into the tumor tissue than Ga-67 citrate. In YS and MM, PNA represented almost the same accumulation as Ga-67 citrate. The localization of PNA into abscess tissue wasn't found although Ga-67 citrate markedly accumulated into abscess tissue as well as tumor tissue. The clearance of PNA from tumor was slower than those from any other organs. Tumor to muscle ratio was 5.1 at 48hrs. and tumor to blood ratio increased with time to 2.3 at 96hrs. These results suggested that radiolabeled PNA may have a potential in the detection of tumor

  2. The Role of Tumor Microenvironment in Chemoresistance: To Survive, Keep Your Enemies Closer

    Science.gov (United States)

    Senthebane, Dimakatso Alice; Rowe, Arielle; Shipanga, Hendrina; Munro, Daniella; Al Mazeedi, Mohammad A. M.; Almazyadi, Hashim A. M.; Kallmeyer, Karlien

    2017-01-01

    Chemoresistance is a leading cause of morbidity and mortality in cancer and it continues to be a challenge in cancer treatment. Chemoresistance is influenced by genetic and epigenetic alterations which affect drug uptake, metabolism and export of drugs at the cellular levels. While most research has focused on tumor cell autonomous mechanisms of chemoresistance, the tumor microenvironment has emerged as a key player in the development of chemoresistance and in malignant progression, thereby influencing the development of novel therapies in clinical oncology. It is not surprising that the study of the tumor microenvironment is now considered to be as important as the study of tumor cells. Recent advances in technological and analytical methods, especially ‘omics’ technologies, has made it possible to identify specific targets in tumor cells and within the tumor microenvironment to eradicate cancer. Tumors need constant support from previously ‘unsupportive’ microenvironments. Novel therapeutic strategies that inhibit such microenvironmental support to tumor cells would reduce chemoresistance and tumor relapse. Such strategies can target stromal cells, proteins released by stromal cells and non-cellular components such as the extracellular matrix (ECM) within the tumor microenvironment. Novel in vitro tumor biology models that recapitulate the in vivo tumor microenvironment such as multicellular tumor spheroids, biomimetic scaffolds and tumor organoids are being developed and are increasing our understanding of cancer cell-microenvironment interactions. This review offers an analysis of recent developments on the role of the tumor microenvironment in the development of chemoresistance and the strategies to overcome microenvironment-mediated chemoresistance. We propose a systematic analysis of the relationship between tumor cells and their respective tumor microenvironments and our data show that, to survive, cancer cells interact closely with tumor

  3. Multiple-Tumor Analysis with MS_Combo Model (Use with BMDS Wizard)

    Science.gov (United States)

    Exercises and procedures on setting up and using the MS_Combo Wizard. The MS_Combo model provides BMD and BMDL estimates for the risk of getting one or more tumors for any combination of tumors observed in a single bioassay.

  4. A Mathematical Model of Prostate Tumor Growth Under Hormone Therapy with Mutation Inhibitor

    Science.gov (United States)

    Tao, Youshan; Guo, Qian; Aihara, Kazuyuki

    2010-04-01

    This paper extends Jackson’s model describing the growth of a prostate tumor with hormone therapy to a new one with hypothetical mutation inhibitors. The new model not only considers the mutation by which androgen-dependent (AD) tumor cells mutate into androgen-independent (AI) ones but also introduces inhibition which is assumed to change the mutation rate. The tumor consists of two types of cells (AD and AI) whose proliferation and apoptosis rates are functions of androgen concentration. The mathematical model represents a free-boundary problem for a nonlinear system of parabolic equations, which describe the evolution of the populations of the above two types of tumor cells. The tumor surface is a free boundary, whose velocity is equal to the cell’s velocity there. Global existence and uniqueness of solutions of this model is proved. Furthermore, explicit formulae of tumor volume at any time t are found in androgen-deprived environment under the assumption of radial symmetry, and therefore the dynamics of tumor growth under androgen-deprived therapy could be predicted by these formulae. Qualitative analysis and numerical simulation show that controlling the mutation may improve the effect of hormone therapy or delay a tumor relapse.

  5. Resonant spectra of malignant breast cancer tumors using the three-dimensional electromagnetic fast multipole model.

    Science.gov (United States)

    El-Shenawee, Magda

    2004-01-01

    This paper presents an intensive numerical study of the resonance scattering of malignant breast cancer tumors. The three-dimensional electromagnetic model, based on the equivalence theorem, is used to obtain induced electric and magnetic currents on breast and tumor surfaces. The results show that the nonspherical malignant tumor can be characterized, based on its spectra, regardless of orientation, incident polarization, or incident or scattered directions. The spectra of the tumor depend solely upon its physical characteristics (i.e., shape and electrical properties); however, their locations are not functions of the depth of the tumor beneath the breast surface. This paper can be a guide in the selection of the frequency range at which the tumor resonates to produce the maximum signature at the receiver.

  6. Tumor-immune interaction, surgical treatment, and cancer recurrence in a mathematical model of melanoma.

    Directory of Open Access Journals (Sweden)

    Steffen Eikenberry

    2009-04-01

    Full Text Available Malignant melanoma is a cancer of the skin arising in the melanocytes. We present a mathematical model of melanoma invasion into healthy tissue with an immune response. We use this model as a framework with which to investigate primary tumor invasion and treatment by surgical excision. We observe that the presence of immune cells can destroy tumors, hold them to minimal expansion, or, through the production of angiogenic factors, induce tumorigenic expansion. We also find that the tumor-immune system dynamic is critically important in determining the likelihood and extent of tumor regrowth following resection. We find that small metastatic lesions distal to the primary tumor mass can be held to a minimal size via the immune interaction with the larger primary tumor. Numerical experiments further suggest that metastatic disease is optimally suppressed by immune activation when the primary tumor is moderately, rather than minimally, metastatic. Furthermore, satellite lesions can become aggressively tumorigenic upon removal of the primary tumor and its associated immune tissue. This can lead to recurrence where total cancer mass increases more quickly than in primary tumor invasion, representing a clinically more dangerous disease state. These results are in line with clinical case studies involving resection of a primary melanoma followed by recurrence in local metastases.

  7. The Role of Neutrophil Myeloperoxidase in Models of Lung Tumor Development

    International Nuclear Information System (INIS)

    Rymaszewski, Amy L.; Tate, Everett; Yimbesalu, Joannes P.; Gelman, Andrew E.; Jarzembowski, Jason A.; Zhang, Hao; Pritchard, Kirkwood A. Jr.; Vikis, Haris G.

    2014-01-01

    Chronic inflammation plays a key tumor-promoting role in lung cancer. Our previous studies in mice demonstrated that neutrophils are critical mediators of tumor promotion in methylcholanthrene (MCA)-initiated, butylated hydroxytoluene (BHT)-promoted lung carcinogenesis. In the present study we investigated the role of neutrophil myeloperoxidase (MPO) activity in this inflammation promoted model. Increased levels of MPO protein and activity were present in the lungs of mice administered BHT. Treatment of mice with N-acetyl lysyltyrosylcysteine amide (KYC), a novel tripeptide inhibitor of MPO, during the inflammatory stage reduced tumor burden. In a separate tumor model, KYC treatment of a Lewis Lung Carcinoma (LLC) tumor graft in mice had no effect on tumor growth, however, mice genetically deficient in MPO had significantly reduced LLC tumor growth. Our observations suggest that MPO catalytic activity is critical during the early stages of tumor development. However, during the later stages of tumor progression, MPO expression independent of catalytic activity appears to be required. Our studies advocate for the use of MPO inhibitors in a lung cancer prevention setting

  8. The role of neutrophil myeloperoxidase in models of lung tumor development.

    Science.gov (United States)

    Rymaszewski, Amy L; Tate, Everett; Yimbesalu, Joannes P; Gelman, Andrew E; Jarzembowski, Jason A; Zhang, Hao; Pritchard, Kirkwood A; Vikis, Haris G

    2014-05-09

    Chronic inflammation plays a key tumor-promoting role in lung cancer. Our previous studies in mice demonstrated that neutrophils are critical mediators of tumor promotion in methylcholanthrene (MCA)-initiated, butylated hydroxytoluene (BHT)-promoted lung carcinogenesis. In the present study we investigated the role of neutrophil myeloperoxidase (MPO) activity in this inflammation promoted model. Increased levels of MPO protein and activity were present in the lungs of mice administered BHT. Treatment of mice with N-acetyl lysyltyrosylcysteine amide (KYC), a novel tripeptide inhibitor of MPO, during the inflammatory stage reduced tumor burden. In a separate tumor model, KYC treatment of a Lewis Lung Carcinoma (LLC) tumor graft in mice had no effect on tumor growth, however, mice genetically deficient in MPO had significantly reduced LLC tumor growth. Our observations suggest that MPO catalytic activity is critical during the early stages of tumor development. However, during the later stages of tumor progression, MPO expression independent of catalytic activity appears to be required. Our studies advocate for the use of MPO inhibitors in a lung cancer prevention setting.

  9. The Role of Neutrophil Myeloperoxidase in Models of Lung Tumor Development

    Energy Technology Data Exchange (ETDEWEB)

    Rymaszewski, Amy L.; Tate, Everett; Yimbesalu, Joannes P. [Department of Pharmacology and Toxicology and MCW Cancer Center, Medical College of Wisconsin, Milwaukee, WI 53226 (United States); Gelman, Andrew E. [Department of Surgery, Washington University in St. Louis, St. Louis, MO 63130 (United States); Jarzembowski, Jason A. [Department of Pathology, Medical College of Wisconsin, Milwaukee, WI 53226 (United States); Zhang, Hao; Pritchard, Kirkwood A. Jr. [Department of Surgery and MCW Cancer Center, Medical College of Wisconsin, Milwaukee, WI 53226 (United States); Vikis, Haris G., E-mail: hvikis@mcw.edu [Department of Pharmacology and Toxicology and MCW Cancer Center, Medical College of Wisconsin, Milwaukee, WI 53226 (United States)

    2014-05-09

    Chronic inflammation plays a key tumor-promoting role in lung cancer. Our previous studies in mice demonstrated that neutrophils are critical mediators of tumor promotion in methylcholanthrene (MCA)-initiated, butylated hydroxytoluene (BHT)-promoted lung carcinogenesis. In the present study we investigated the role of neutrophil myeloperoxidase (MPO) activity in this inflammation promoted model. Increased levels of MPO protein and activity were present in the lungs of mice administered BHT. Treatment of mice with N-acetyl lysyltyrosylcysteine amide (KYC), a novel tripeptide inhibitor of MPO, during the inflammatory stage reduced tumor burden. In a separate tumor model, KYC treatment of a Lewis Lung Carcinoma (LLC) tumor graft in mice had no effect on tumor growth, however, mice genetically deficient in MPO had significantly reduced LLC tumor growth. Our observations suggest that MPO catalytic activity is critical during the early stages of tumor development. However, during the later stages of tumor progression, MPO expression independent of catalytic activity appears to be required. Our studies advocate for the use of MPO inhibitors in a lung cancer prevention setting.

  10. The Role of Neutrophil Myeloperoxidase in Models of Lung Tumor Development

    Directory of Open Access Journals (Sweden)

    Amy L. Rymaszewski

    2014-05-01

    Full Text Available Chronic inflammation plays a key tumor-promoting role in lung cancer. Our previous studies in mice demonstrated that neutrophils are critical mediators of tumor promotion in methylcholanthrene (MCA-initiated, butylated hydroxytoluene (BHT-promoted lung carcinogenesis. In the present study we investigated the role of neutrophil myeloperoxidase (MPO activity in this inflammation promoted model. Increased levels of MPO protein and activity were present in the lungs of mice administered BHT. Treatment of mice with N-acetyl lysyltyrosylcysteine amide (KYC, a novel tripeptide inhibitor of MPO, during the inflammatory stage reduced tumor burden. In a separate tumor model, KYC treatment of a Lewis Lung Carcinoma (LLC tumor graft in mice had no effect on tumor growth, however, mice genetically deficient in MPO had significantly reduced LLC tumor growth. Our observations suggest that MPO catalytic activity is critical during the early stages of tumor development. However, during the later stages of tumor progression, MPO expression independent of catalytic activity appears to be required. Our studies advocate for the use of MPO inhibitors in a lung cancer prevention setting.

  11. An interdisciplinary computational/experimental approach to evaluate drug-loaded gold nanoparticle tumor cytotoxicity

    Science.gov (United States)

    Curtis, Louis T; England, Christopher G; Wu, Min; Lowengrub, John; Frieboes, Hermann B

    2016-01-01

    Aim: Clinical translation of cancer nanotherapy has largely failed due to the infeasibility of optimizing the complex interaction of nano/drug/tumor/patient parameters. We develop an interdisciplinary approach modeling diffusive transport of drug-loaded gold nanoparticles in heterogeneously-vascularized tumors. Materials & methods: Evaluated lung cancer cytotoxicity to paclitaxel/cisplatin using novel two-layer (hexadecanethiol/phosphatidylcholine) and three-layer (with high-density-lipoprotein) nanoparticles. Computer simulations calibrated to in-vitro data simulated nanotherapy of heterogeneously-vascularized tumors. Results: Evaluation of free-drug cytotoxicity between monolayer/spheroid cultures demonstrates a substantial differential, with increased resistance conferred by diffusive transport. Nanoparticles had significantly higher efficacy than free-drug. Simulations of nanotherapy demonstrate 9.5% (cisplatin) and 41.3% (paclitaxel) tumor radius decrease. Conclusion: Interdisciplinary approach evaluating gold nanoparticle cytotoxicity and diffusive transport may provide insight into cancer nanotherapy. PMID:26829163

  12. Classification of materials for conducting spheroids based on the first order polarization tensor

    Science.gov (United States)

    Khairuddin, TK Ahmad; Mohamad Yunos, N.; Aziz, ZA; Ahmad, T.; Lionheart, WRB

    2017-09-01

    Polarization tensor is an old terminology in mathematics and physics with many recent industrial applications including medical imaging, nondestructive testing and metal detection. In these applications, it is theoretically formulated based on the mathematical modelling either in electrics, electromagnetics or both. Generally, polarization tensor represents the perturbation in the electric or electromagnetic fields due to the presence of conducting objects and hence, it also desribes the objects. Understanding the properties of the polarization tensor is necessary and important in order to apply it. Therefore, in this study, when the conducting object is a spheroid, we show that the polarization tensor is positive-definite if and only if the conductivity of the object is greater than one. In contrast, we also prove that the polarization tensor is negative-definite if and only if the conductivity of the object is between zero and one. These features categorize the conductivity of the spheroid based on in its polarization tensor and can then help to classify the material of the spheroid.

  13. Mathematical modeling of tumor-associated macrophage interactions with the cancer microenvironment.

    Science.gov (United States)

    Mahlbacher, Grace; Curtis, Louis T; Lowengrub, John; Frieboes, Hermann B

    2018-01-30

    Immuno-oncotherapy has emerged as a promising means to target cancer. In particular, therapeutic manipulation of tumor-associated macrophages holds promise due to their various and sometimes opposing roles in tumor progression. It is established that M1-type macrophages suppress tumor progression while M2-types support it. Recently, Tie2-expressing macrophages (TEM) have been identified as a distinct sub-population influencing tumor angiogenesis and vascular remodeling as well as monocyte differentiation. This study develops a modeling framework to evaluate macrophage interactions with the tumor microenvironment, enabling assessment of how these interactions may affect tumor progression. M1, M2, and Tie2 expressing variants are integrated into a model of tumor growth representing a metastatic lesion in a highly vascularized organ, such as the liver. Behaviors simulated include M1 release of nitric oxide (NO), M2 release of growth-promoting factors, and TEM facilitation of angiogenesis via Angiopoietin-2 and promotion of monocyte differentiation into M2 via IL-10. The results show that M2 presence leads to larger tumor growth regardless of TEM effects, implying that immunotherapeutic strategies that lead to TEM ablation may fail to restrain growth when the M2 represents a sizeable population. As TEM pro-tumor effects are less pronounced and on a longer time scale than M1-driven tumor inhibition, a more nuanced approach to influence monocyte differentiation taking into account the tumor state (e.g., under chemotherapy) may be desirable. The results highlight the dynamic interaction of macrophages within a growing tumor, and, further, establish the initial feasibility of a mathematical framework that could longer term help to optimize cancer immunotherapy.

  14. Stiffness analysis of 3D spheroids using microtweezers.

    Directory of Open Access Journals (Sweden)

    Devina Jaiswal

    Full Text Available We describe a novel mechanical characterization method that has directly measured the stiffness of cancer spheroids for the first time to our knowledge. Stiffness is known to be a key parameter that characterizes cancerous and normal cells. Atomic force microscopy or optical tweezers have been typically used for characterization of single cells with the measurable forces ranging from sub pN to a few hundred nN, which are not suitable for measurement of larger 3D cellular structures such as spheroids, whose mechanical characteristics have not been fully studied. Here, we developed microtweezers that measure forces from sub hundred nN to mN. The wide force range was achieved by the use of replaceable cantilevers fabricated from SU8, and brass. The chopstick-like motion of the two cantilevers facilitates easy handling of samples and microscopic observation for mechanical characterization. The cantilever bending was optically tracked to find the applied force and sample stiffness. The efficacy of the method was demonstrated through stiffness measurement of agarose pillars with known concentrations. Following the initial system evaluation with agarose, two cancerous (T47D and BT474 and one normal epithelial (MCF 10A breast cell lines were used to conduct multi-cellular spheroid measurements to find Young's moduli of 230, 420 and 1250 Pa for BT474, T47D, and MCF 10A, respectively. The results showed that BT474 and T47D spheroids are six and three times softer than epithelial MCF10A spheroids, respectively. Our method successfully characterized samples with wide range of Young's modulus including agarose (25-100 kPa, spheroids of cancerous and non-malignant cells (190-200 μm, 230-1250 Pa and collagenase-treated spheroids (215 μm, 130 Pa.

  15. Human Cardiac Progenitor Spheroids Exhibit Enhanced Engraftment Potential.

    Directory of Open Access Journals (Sweden)

    Francesca Oltolina

    Full Text Available A major obstacle to an effective myocardium stem cell therapy has always been the delivery and survival of implanted stem cells in the heart. Better engraftment can be achieved if cells are administered as cell aggregates, which maintain their extra-cellular matrix (ECM. We have generated spheroid aggregates in less than 24 h by seeding human cardiac progenitor cells (hCPCs onto methylcellulose hydrogel-coated microwells. Cells within spheroids maintained the expression of stemness/mesenchymal and ECM markers, growth factors and their cognate receptors, cardiac commitment factors, and metalloproteases, as detected by immunofluorescence, q-RT-PCR and immunoarray, and expressed a higher, but regulated, telomerase activity. Compared to cells in monolayers, 3D spheroids secreted also bFGF and showed MMP2 activity. When spheroids were seeded on culture plates, the cells quickly migrated, displaying an increased wound healing ability with or without pharmacological modulation, and reached confluence at a higher rate than cells from conventional monolayers. When spheroids were injected in the heart wall of healthy mice, some cells migrated from the spheroids, engrafted, and remained detectable for at least 1 week after transplantation, while, when the same amount of cells was injected as suspension, no cells were detectable three days after injection. Cells from spheroids displayed the same engraftment capability when they were injected in cardiotoxin-injured myocardium. Our study shows that spherical in vivo ready-to-implant scaffold-less aggregates of hCPCs able to engraft also in the hostile environment of an injured myocardium can be produced with an economic, easy and fast protocol.

  16. Simulation of diffuse photon migration in tissue by a Monte Carlo method derived from the optical scattering of spheroids.

    Science.gov (United States)

    Hart, Vern P; Doyle, Timothy E

    2013-09-01

    A Monte Carlo method was derived from the optical scattering properties of spheroidal particles and used for modeling diffuse photon migration in biological tissue. The spheroidal scattering solution used a separation of variables approach and numerical calculation of the light intensity as a function of the scattering angle. A Monte Carlo algorithm was then developed which utilized the scattering solution to determine successive photon trajectories in a three-dimensional simulation of optical diffusion and resultant scattering intensities in virtual tissue. Monte Carlo simulations using isotropic randomization, Henyey-Greenstein phase functions, and spherical Mie scattering were additionally developed and used for comparison to the spheroidal method. Intensity profiles extracted from diffusion simulations showed that the four models differed significantly. The depth of scattering extinction varied widely among the four models, with the isotropic, spherical, spheroidal, and phase function models displaying total extinction at depths of 3.62, 2.83, 3.28, and 1.95 cm, respectively. The results suggest that advanced scattering simulations could be used as a diagnostic tool by distinguishing specific cellular structures in the diffused signal. For example, simulations could be used to detect large concentrations of deformed cell nuclei indicative of early stage cancer. The presented technique is proposed to be a more physical description of photon migration than existing phase function methods. This is attributed to the spheroidal structure of highly scattering mitochondria and elongation of the cell nucleus, which occurs in the initial phases of certain cancers. The potential applications of the model and its importance to diffusive imaging techniques are discussed.

  17. Inferring Growth Control Mechanisms in Growing Multi-cellular Spheroids of NSCLC Cells from Spatial-Temporal Image Data

    Science.gov (United States)

    Müller, Margareta; Vignon-Clementel, Irene E.; Drasdo, Dirk

    2016-01-01

    We develop a quantitative single cell-based mathematical model for multi-cellular tumor spheroids (MCTS) of SK-MES-1 cells, a non-small cell lung cancer (NSCLC) cell line, growing under various nutrient conditions: we confront the simulations performed with this model with data on the growth kinetics and spatial labeling patterns for cell proliferation, extracellular matrix (ECM), cell distribution and cell death. We start with a simple model capturing part of the experimental observations. We then show, by performing a sensitivity analysis at each development stage of the model that its complexity needs to be stepwise increased to account for further experimental growth conditions. We thus ultimately arrive at a model that mimics the MCTS growth under multiple conditions to a great extent. Interestingly, the final model, is a minimal model capable of explaining all data simultaneously in the sense, that the number of mechanisms it contains is sufficient to explain the data and missing out any of its mechanisms did not permit fit between all data and the model within physiological parameter ranges. Nevertheless, compared to earlier models it is quite complex i.e., it includes a wide range of mechanisms discussed in biological literature. In this model, the cells lacking oxygen switch from aerobe to anaerobe glycolysis and produce lactate. Too high concentrations of lactate or too low concentrations of ATP promote cell death. Only if the extracellular matrix density overcomes a certain threshold, cells are able to enter the cell cycle. Dying cells produce a diffusive growth inhibitor. Missing out the spatial information would not permit to infer the mechanisms at work. Our findings suggest that this iterative data integration together with intermediate model sensitivity analysis at each model development stage, provide a promising strategy to infer predictive yet minimal (in the above sense) quantitative models of tumor growth, as prospectively of other tissue

  18. Shigella mediated depletion of macrophages in a murine breast cancer model is associated with tumor regression.

    Directory of Open Access Journals (Sweden)

    Katharina Galmbacher

    Full Text Available A tumor promoting role of macrophages has been described for a transgenic murine breast cancer model. In this model tumor-associated macrophages (TAMs represent a major component of the leukocytic infiltrate and are associated with tumor progression. Shigella flexneri is a bacterial pathogen known to specificly induce apotosis in macrophages. To evaluate whether Shigella-induced removal of macrophages may be sufficient for achieving tumor regression we have developed an attenuated strain of S. flexneri (M90TDeltaaroA and infected tumor bearing mice. Two mouse models were employed, xenotransplantation of a murine breast cancer cell line and spontanous breast cancer development in MMTV-HER2 transgenic mice. Quantitative analysis of bacterial tumor targeting demonstrated that attenuated, invasive Shigella flexneri primarily infected TAMs after systemic administration. A single i.v. injection of invasive M90TDeltaaroA resulted in caspase-1 dependent apoptosis of TAMs followed by a 74% reduction in tumors of transgenic MMTV-HER-2 mice 7 days post infection. TAM depletion was sustained and associated with complete tumor regression.These data support TAMs as useful targets for antitumor therapy and highlight attenuated bacterial pathogens as potential tools.

  19. A mathematical model for IL-6-mediated, stem cell driven tumor growth and targeted treatment

    Science.gov (United States)

    Nör, Jacques Eduardo

    2018-01-01

    Targeting key regulators of the cancer stem cell phenotype to overcome their critical influence on tumor growth is a promising new strategy for cancer treatment. Here we present a modeling framework that operates at both the cellular and molecular levels, for investigating IL-6 mediated, cancer stem cell driven tumor growth and targeted treatment with anti-IL6 antibodies. Our immediate goal is to quantify the influence of IL-6 on cancer stem cell self-renewal and survival, and to characterize the subsequent impact on tumor growth dynamics. By including the molecular details of IL-6 binding, we are able to quantify the temporal changes in fractional occupancies of bound receptors and their influence on tumor volume. There is a strong correlation between the model output and experimental data for primary tumor xenografts. We also used the model to predict tumor response to administration of the humanized IL-6R monoclonal antibody, tocilizumab (TCZ), and we found that as little as 1mg/kg of TCZ administered weekly for 7 weeks is sufficient to result in tumor reduction and a sustained deceleration of tumor growth. PMID:29351275

  20. Ultrasonic characterization of three animal mammary tumors from three-dimensional acoustic tissue models

    Science.gov (United States)

    Mamou, Jonathan M.

    This dissertation investigated how three-dimensional (3D) tissue models can be used to improve ultrasonic tissue characterization (UTC) techniques. Anatomic sites in tissue responsible for ultrasonic scattering are unknown, which limits the potential applications of ultrasound for tumor diagnosis. Accurate 3D models of tumor tissues may help identify the scattering sites. Three mammary tumors were investigated: a rat fibroadenoma, a mouse carcinoma, and a mouse sarcoma. A 3D acoustic tissue model, termed 3D impedance map (3DZM), was carefully constructed from consecutive histologic sections for each tumor. Spectral estimates (scatterer size and acoustic concentration) were obtained from the 3DZMs and compared to the same estimates obtained with ultrasound. Scatterer size estimates for three tumors were found to be similar (within 10%). The 3DZMs were also used to extract tissue-specific scattering models. The scattering models were found to allow clear distinction between the three tumors. This distinction demonstrated that UTC techniques may be helpful for noninvasive clinical tumor diagnosis.

  1. A switching control law approach for cancer immunotherapy of an evolutionary tumor growth model.

    Science.gov (United States)

    Doban, Alina I; Lazar, Mircea

    2017-02-01

    We propose a new approach for tumor immunotherapy which is based on a switching control strategy defined on domains of attraction of equilibria of interest. For this, we consider a recently derived model which captures the effects of the tumor cells on the immune system and viceversa, through predator-prey competition terms. Additionally, it incorporates the immune system's mechanism for producing hunting immune cells, which makes the model suitable for immunotherapy strategies analysis and design. For computing domains of attraction for the tumor nonlinear dynamics, and thus, for deriving immunotherapeutic strategies we employ rational Lyapunov functions. Finally, we apply the switching control strategy to destabilize an invasive tumor equilibrium and steer the system trajectories to tumor dormancy. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Long-term BPA infusions. Evaluation in the rat brain tumor and rat spinal cord models

    International Nuclear Information System (INIS)

    Coderre, J.A.; Micca, P.L.; Nawrocky, M.M.; Joel, D.D.; Morris, G.M.

    2000-01-01

    In the BPA-based dose escalation clinical trial, the observations of tumor recurrence in areas of extremely high calculated tumor doses suggest that the BPA distribution is non-uniform. Longer (6-hour) i.v. infusions of BPA are evaluated in the rat brain tumor and spinal cord models to address the questions of whether long-term infusions are more effective against the tumor and whether long-term infusions are detrimental in the central nervous system. In the rat spinal cord, the 50% effective doses (ED 50 ) for myeloparesis were not significantly different after a single i.p. injection of BPA-fructose or a 6 hour i.v. infusion. In the rat 9L gliosarcoma brain tumor model, BNCT following 2-hr or 6-hr infusions of BPA-F produced similar levels of long term survival. (author)

  3. Bioprinting-Based High-Throughput Fabrication of Three-Dimensional MCF-7 Human Breast Cancer Cellular Spheroids

    Directory of Open Access Journals (Sweden)

    Kai Ling

    2015-06-01

    Full Text Available Cellular spheroids serving as three-dimensional (3D in vitro tissue models have attracted increasing interest for pathological study and drug-screening applications. Various methods, including microwells in particular, have been developed for engineering cellular spheroids. However, these methods usually suffer from either destructive molding operations or cell loss and non-uniform cell distribution among the wells due to two-step molding and cell seeding. We have developed a facile method that utilizes cell-embedded hydrogel arrays as templates for concave well fabrication and in situ MCF-7 cellular spheroid formation on a chip. A custom-built bioprinting system was applied for the fabrication of sacrificial gelatin arrays and sequentially concave wells in a high-throughput, flexible, and controlled manner. The ability to achieve in situ cell seeding for cellular spheroid construction was demonstrated with the advantage of uniform cell seeding and the potential for programmed fabrication of tissue models on chips. The developed method holds great potential for applications in tissue engineering, regenerative medicine, and drug screening.

  4. A novel xenograft model in zebrafish for high-resolution investigating dynamics of neovascularization in tumors.

    Directory of Open Access Journals (Sweden)

    Chengjian Zhao

    Full Text Available Tumor neovascularization is a highly complex process including multiple steps. Understanding this process, especially the initial stage, has been limited by the difficulties of real-time visualizing the neovascularization embedded in tumor tissues in living animal models. In the present study, we have established a xenograft model in zebrafish by implanting mammalian tumor cells into the perivitelline space of 48 hours old Tg(Flk1:EGFP transgenic zebrafish embryos. With this model, we dynamically visualized the process of tumor neovascularization, with unprecedented high-resolution, including new sprouts from the host vessels and the origination from VEGFR2(+ individual endothelial cells. Moreover, we quantified their contributions during the formation of vascular network in tumor. Real-time observations revealed that angiogenic sprouts in tumors preferred to connect each other to form endothelial loops, and more and more endothelial loops accumulated into the irregular and chaotic vascular network. The over-expression of VEGF165 in tumor cells significantly affected the vascularization in xenografts, not only the number and size of neo-vessels but the abnormalities of tumor vascular architecture. The specific inhibitor of VEGFR2, SU5416, significantly inhibited the vascularization and the growth of melanoma xenografts, but had little affects to normal vessels in zebrafish. Thus, this zebrafish/tumor xenograft model not only provides a unique window to investigate the earliest events of tumoral neoangiogenesis, but is sensitive to be used as an experimental platform to rapidly and visually evaluate functions of angiogenic-related genes. Finally, it also offers an efficient and cost-effective means for the rapid evaluation of anti-angiogenic chemicals.

  5. Modeling the Dichotomy of the Immune Response to Cancer: Cytotoxic Effects and Tumor-Promoting Inflammation.

    Science.gov (United States)

    Wilkie, Kathleen P; Hahnfeldt, Philip

    2017-06-01

    Although the immune response is often regarded as acting to suppress tumor growth, it is now clear that it can be both stimulatory and inhibitory. The interplay between these competing influences has complex implications for tumor development, cancer dormancy, and immunotherapies. In fact, early immunotherapy failures were partly due to a lack in understanding of the nonlinear growth dynamics these competing immune actions may cause. To study this biological phenomenon theoretically, we construct a minimally parameterized framework that incorporates all aspects of the immune response. We combine the effects of all immune cell types, general principles of self-limited logistic growth, and the physical process of inflammation into one quantitative setting. Simulations suggest that while there are pro-tumor or antitumor immunogenic responses characterized by larger or smaller final tumor volumes, respectively, each response involves an initial period where tumor growth is stimulated beyond that of growth without an immune response. The mathematical description is non-identifiable which allows an ensemble of parameter sets to capture inherent biological variability in tumor growth that can significantly alter tumor-immune dynamics and thus treatment success rates. The ability of this model to predict non-intuitive yet clinically observed patterns of immunomodulated tumor growth suggests that it may provide a means to help classify patient response dynamics to aid identification of appropriate treatments exploiting immune response to improve tumor suppression, including the potential attainment of an immune-induced dormant state.

  6. Efficacy of continuous treatment with radiation in a rat brain-tumor model

    International Nuclear Information System (INIS)

    Wheeler, K.T.; Kaufman, K.

    1981-01-01

    Rats bearing intracerebral 9L/Ro tumors were treated with 10 daily fractions of cesium-137 gamma-rays, BCNU, or combinations of these to agents beginning on either Day 10 or Day 12 after implantation. The treatments were administered either 5 days/week for 2 weeks, with the weekend off, or 10 consecutive days. The median day of death for untreated tumor-bearing rats was Day 15, so Day 12 tumors can be considered late tumors and Day 10 tumors can be considered moderately early. Although all single- and multiple-agent treatments significantly (p less than 0.05) increased the lifespan of tumor-bearing rats over that of the untreated controls, and all multiple-agent schedules significantly (p less than 0.05) increased the lifespan over that of the single-agent therapies, none of the 10 consecutive day schedules increased the lifespan of tumor-bearing rats significantly (p less than 0.2) over that obtained with the 5-day/week schedules. Thus, the evidence from this tumor model suggests that no significant improvement in lifespan would be expected if malignant brain tumors were treated with radiation 7 days a week, either alone or in combination with chemotherapeutic agents such as BCNU

  7. Dopamine receptor antagonist thioridazine inhibits tumor growth in a murine breast cancer model.

    Science.gov (United States)

    Yin, Tao; He, Sisi; Shen, Guobo; Ye, Tinghong; Guo, Fuchun; Wang, Yongsheng

    2015-09-01

    Neuropsychological factors have been shown to influence tumor progression and therapeutic response. The present study investigated the effect of the dopamine receptor antagonist thioridazine on murine breast cancer. The anti‑tumor efficacy of thioridazine was assessed using a murine breast cancer model. Cell apoptosis and proliferation were analyzed in vitro using flow cytometry (FCM) and the MTT assay, respectively. Western blot analysis was performed to assess Akt, phosphorylated (p)‑Akt, signal transducer and activator of transcription (STAT) 3, p‑STAT3 and p‑p65 in tumor cells following treatment with thioridazine. The Ki67 index and the number of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)‑positive apoptotic cells were assessed in the tumor sections. Thioridazine was found to reduce tumor growth, inhibit tumor cell proliferation and induce apoptosis in a dose‑ and time‑dependent manner in vitro. Thioridazine was also found to markedly inhibit tumor proliferation and induce tumor cell apoptosis in vivo as shown by the lower Ki67 index and increase in TUNEL‑positive cells. In addition, thioridazine was observed to inhibit the activation of the canonical nuclear factor κ‑light‑chain‑enhancer of activated B cells pathway and exert anti‑tumor effects by remodeling the tumor stroma, as well as inhibit angiogenesis in the tumor microenvironment. In conclusion, thioridazine was found to significantly inhibit breast tumor growth and the potential for thioridazine to be used in cancer therapy may be re‑evaluated and investigated in clinical settings.

  8. Delay equations modeling the effects of phase-specific drugs and immunotherapy on proliferating tumor cells.

    Science.gov (United States)

    Barbarossa, Maria Vittoria; Kuttler, Christina; Zinsl, Jonathan

    2012-04-01

    In this work we present a mathematical model for tumor growth based on the biology of the cell cycle. For an appropriate description of the effects of phase-specific drugs, it is necessary to look at the cell cycle and its phases. Our model reproduces the dynamics of three different tumor cell populations: quiescent cells, cells during the interphase and mitotic cells. Starting from a partial differential equations (PDEs) setting, a delay differential equations (DDE) model is derived for an easier and more realistic approach. Our equations also include interactions of tumor cells with immune system effectors. We investigate the model both from the analytical and the numerical point of view, give conditions for positivity of solutions and focus on the stability of the cancer-free equilibrium. Different immunotherapeutic strategies and their effects on the tumor growth are considered, as well.

  9. A kinematic study of the Fornax dwarf spheroidal galaxy

    Science.gov (United States)

    Mateo, Mario; Olszewski, Edward; Welch, Douglas L.; Fischer, Philippe; Kunkel, William

    1991-01-01

    Precise radial velocities of 44 stars and four globular clusters located in two fields of the Fornax dwarf spheroidal galaxy are obtained on the basis of photon-counting echelle spectroscopy with a resolution of approximately 14 km/s. BV CCD photometry of the giant branch of Fornax in both fields are presented as well. A variety of kinematic and photometric criteria are used to identify 10-12 probable nonmembers in the present sample of spectroscopically observed stars. Based on the most probable members, the mean heliocentric systemic velocity of Fornax is 53.0 + or - 1.8 km/s, with no evidence of any significant rotation about the minor axis. The intrinsic velocity dispersion of the stars in Fornax's central field is 9.9 + or - 1.7 km/s, while for the outer field the velocity dispersion is 1.20 + or - 2.8 km/s. The true central velocity dispersion is not more than 1.6 km/s larger than the observed central dispersions for a number of reasonable models.

  10. Cystatin C deficiency suppresses tumor growth in a breast cancer model through decreased proliferation of tumor cells.

    Science.gov (United States)

    Završnik, Janja; Butinar, Miha; Prebanda, Mojca Trstenjak; Krajnc, Aleksander; Vidmar, Robert; Fonović, Marko; Grubb, Anders; Turk, Vito; Turk, Boris; Vasiljeva, Olga

    2017-09-26

    Cysteine cathepsins are proteases that, in addition to their important physiological functions, have been associated with multiple pathologies, including cancer. Cystatin C (CstC) is a major endogenous inhibitor that regulates the extracellular activity of cysteine cathepsins. We investigated the role of cystatin C in mammary cancer using CstC knockout mice and a mouse model of breast cancer induced by expression of the polyoma middle T oncoprotein (PyMT) in the mammary epithelium. We showed that the ablation of CstC reduced the rate of mammary tumor growth. Notably, a decrease in the proliferation of CstC knockout PyMT tumor cells was demonstrated ex vivo and in vitro , indicating a role for this protease inhibitor in signaling pathways that control cell proliferation. An increase in phosphorylated p-38 was observed in CstC knockout tumors, suggesting a novel function for cystatin C in cancer development, independent of the TGF-β pathway. Moreover, proteomic analysis of the CstC wild-type and knockout PyMT primary cell secretomes revealed a decrease in the levels of 14-3-3 proteins in the secretome of knock-out cells, suggesting a novel link between cysteine cathepsins, cystatin C and 14-3-3 proteins in tumorigenesis, calling for further investigations.

  11. Dosimetry study of PHOTOFRIN-mediated photodynamic therapy in a mouse tumor model

    Science.gov (United States)

    Qiu, Haixia; Kim, Michele M.; Penjweini, Rozhin; Zhu, Timothy C.

    2016-03-01

    It is well known in photodynamic therapy (PDT) that there is a large variability between PDT light dose and therapeutic outcomes. An explicit dosimetry model using apparent reacted 1O2 concentration [1O2]rx has been developed as a PDT dosimetric quantity to improve the accuracy of the predicted ability of therapeutic efficacy. In this study, this explicit macroscopic singlet oxygen model was adopted to establish the correlation between calculated reacted [1O2]rx and the tumor growth using Photofrin-mediated PDT in a mouse tumor model. Mice with radiation-induced fibrosarcoma (RIF) tumors were injected with Photofrin at a dose of 5 mg/kg. PDT was performed 24h later with different fluence rates (50, 75 and 150 mW/cm2) and different fluences (50 and 135 J/cm2) using a collimated light applicator coupled to a 630nm laser. The tumor volume was monitored daily after PDT and correlated with the total light fluence and [1O2]rx. Photophysical parameters as well as the singlet oxygen threshold dose for this sensitizer and the RIF tumor model were determined previously. The result showed that tumor growth rate varied greatly with light fluence for different fluence rates while [1O2]rx had a good correlation with the PDT-induced tumor growth rate. This preliminary study indicated that [1O2]rx could serve as a better dosimetric predictor for predicting PDT outcome than PDT light dose.

  12. Molecular Analysis of Medaka Tumors: New Models for Carcinogenicity Testing

    Science.gov (United States)

    1994-07-07

    51 A1 4 INTRODUCTION For over twenty years, tumors in fish and other lower vertebrates and invertebrates have been systematically...class of vertebrates , with over 20,000 described species. Their phylogenetic position relative to the other vertebrates makes them ideal for comparative...provide large numbers of eggs and are easy to culture. The genetics, developmental biology and embryology are well-documented (Yamamoto 1975). Induction

  13. Ovarian Tumor-Stroma Interactions in an In Vivo Orthotopic Model

    Science.gov (United States)

    2012-08-01

    dog brain [31]; Ugt8a, transfers galactose to ceramide [32]; Zc4h2, mental retardation [33]; Kctd12b, GABA(B) receptor subunit [34]; Lrrk2...chamber model is to make possible the visualization of tumors that are normally buried and inaccessi- ble, such as pancreatic , prostate or lung tu...angiogenesis and pancreatic tumor growth [78]. Finally, this model is widely used to demonstrate the vascular effects of new anti-angiogenic

  14. Reactive astrocytes potentiate tumor aggressiveness in a murine glioma resection and recurrence model.

    Science.gov (United States)

    Okolie, Onyinyechukwu; Bago, Juli R; Schmid, Ralf S; Irvin, David M; Bash, Ryan E; Miller, C Ryan; Hingtgen, Shawn D

    2016-12-01

    Surgical resection is a universal component of glioma therapy. Little is known about the postoperative microenvironment due to limited preclinical models. Thus, we sought to develop a glioma resection and recurrence model in syngeneic immune-competent mice to understand how surgical resection influences tumor biology and the local microenvironment. We genetically engineered cells from a murine glioma mouse model to express fluorescent and bioluminescent reporters. Established allografts were resected using image-guided microsurgery. Postoperative tumor recurrence was monitored by serial imaging, and the peritumoral microenvironment was characterized by histopathology and immunohistochemistry. Coculture techniques were used to explore how astrocyte injury influences tumor aggressiveness in vitro. Transcriptome and secretome alterations in injured astrocytes was examined by RNA-seq and Luminex. We found that image-guided resection achieved >90% reduction in tumor volume but failed to prevent both local and distant tumor recurrence. Immunostaining for glial fibrillary acidic protein and nestin showed that resection-induced injury led to temporal and spatial alterations in reactive astrocytes within the peritumoral microenvironment. In vitro, we found that astrocyte injury induced transcriptome and secretome alterations and promoted tumor proliferation, as well as migration. This study demonstrates a unique syngeneic model of glioma resection and recurrence in immune-competent mice. Furthermore, this model provided insights into the pattern of postsurgical tumor recurrence and changes in the peritumoral microenvironment, as well as the impact of injured astrocytes on glioma growth and invasion. A better understanding of the postsurgical tumor microenvironment will allow development of targeted anticancer agents that improve surgery-mediated effects on tumor biology. © The Author(s) 2016. Published by Oxford University Press on behalf of the Society for Neuro

  15. Nicotine promotes tumor growth and metastasis in mouse models of lung cancer.

    Directory of Open Access Journals (Sweden)

    Rebecca Davis

    2009-10-01

    Full Text Available Nicotine is the major addictive component of tobacco smoke. Although nicotine is generally thought to have limited ability to initiate cancer, it can induce cell proliferation and angiogenesis in a variety of systems. These properties might enable nicotine to facilitate the growth of tumors already initiated. Here we show that nicotine significantly promotes the progression and metastasis of tumors in mouse models of lung cancer. This effect was observed when nicotine was administered through intraperitoneal injections, or through over-the-counter transdermal patches.In the present study, Line1 mouse adenocarcinoma cells were implanted subcutaneously into syngenic BALB/c mice. Nicotine administration either by intraperitoneal (i.p. injection or transdermal patches caused a remarkable increase in the size of implanted Line1 tumors. Once the tumors were surgically removed, nicotine treated mice had a markedly higher tumor recurrence (59.7% as compared to the vehicle treated mice (19.5%. Nicotine also increased metastasis of dorsally implanted Line1 tumors to the lungs by 9 folds. These studies on transplanted tumors were extended to a mouse model where the tumors were induced by the tobacco carcinogen, NNK. Lung tumors were initiated in A/J mice by i.p. injection of NNK; administration of 1 mg/kg nicotine three times a week led to an increase in the size and the number of tumors formed in the lungs. In addition, nicotine significantly reduced the expression of epithelial markers, E-Cadherin and beta-Catenin as well as the tight junction protein ZO-1; these tumors also showed an increased expression of the alpha(7 nAChR subunit. We believe that exposure to nicotine either by tobacco smoke or nicotine supplements might facilitate increased tumor growth and metastasis.Our earlier results indicated that nicotine could induce invasion and epithelial-mesenchymal transition (EMT in cultured lung, breast and pancreatic cancer cells. This study

  16. Failure of the cultivated mushroom (Agaricus bisporus) to induce tumors in the A/J mouse lung tumor model

    DEFF Research Database (Denmark)

    Pilegaard, Kirsten; Kristiansen, E.; Meyer, Otto A.

    1997-01-01

    We studied whether the cultivated mushroom (Agaricus bisporus) or 4-(carboxy)phenylhydrazine (CP) induce lung adenomas in the A/J mouse lung tumor model. For 26 weeks female mice were fed a semisynthetic diet where 11 or 22% of the diet was replaced by freeze-dried mushrooms. The intake...... of the mushroom diets was equivalent to an intake of agaritine, the major phenylhydrazine derivative occurring in the mushroom, of 92 or 166 mg/kg body weight per day. The intake of CP was 106 mg/kg body weight per day. Neither the;freeze-dried mushroom nor CP induced statistically significant increased numbers...

  17. Unsteady analysis of six-DOF motion of a 6:1 prolate spheroid in viscous fluid

    Science.gov (United States)

    Xiong, Ying; Guan, Hui; Wu, ChuiJie

    2017-11-01

    Free-moving simulations of airplanes, submarines and other automobiles under extreme and emergency conditions are becoming increasingly important from operational and tactical perspectives. Such simulations are fairly challenging due to the extreme unsteady motions and high Re (Reynolds) numbers. The aim of this study is to perform a six-DOF motion simulation of a 6:1 prolate spheroid that is falling in a fluid field. Prior to conducting the six-DOF simulation, some verification simulations were performed. First, a laminar flow past an inclined prolate spheroid at a Re number of 1000 and incidence angle of 45° with a tetrahedral mesh was simulated to verify the relevant targeted discrete method for an unstructured mesh. Second, to verify the LES (large eddy simulation) models and dependent parameters for the DDES (delayed detached eddy simulation), a turbulent flow past a sphere was performed at a subcritical Re number of 10000. Third, a steady maneuvering problem about a prolate spheroid pitching up from 0° to 30° incidence at a uniform angular velocity was established based on a dynamic tetrahedral mesh with changing topology and the ALE (arbitrary Lagrangian-Eulerian) method of fluid-structure coupling at a Re number of 4.2 × 106. Finally, two six-DOF motions of an inclined 6:1 prolate spheroid at an initial incidence of 45° were simulated at different Re numbers of 10000 and 4.2 × 106.

  18. Invasiveness and metastasis of retinoblastoma in an orthotopic zebrafish tumor model

    Science.gov (United States)

    Chen, Xiaoyun; Wang, Jian; Cao, Ziquan; Hosaka, Kayoko; Jensen, Lasse; Yang, Huasheng; Sun, Yuping; Zhuang, Rujie; Liu, Yizhi; Cao, Yihai

    2015-01-01

    Retinoblastoma is a highly invasive malignant tumor that often invades the brain and metastasizes to distal organs through the blood stream. Invasiveness and metastasis of retinoblastoma can occur at the early stage of tumor development. However, an optimal preclinical model to study retinoblastoma invasiveness and metastasis in relation to drug treatment has not been developed. Here, we developed an orthotopic zebrafish model in which retinoblastoma invasion and metastasis can be monitored at a single cell level. We took the advantages of immune privilege and transparent nature of developing zebrafish embryos. Intravitreal implantation of color-coded retinoblastoma cells allowed us to kinetically monitor tumor cell invasion and metastasis. Further, interactions between retinoblastoma cells and surrounding microvasculatures were studied using a transgenic zebrafish that exhibited green fluorescent signals in blood vessels. We discovered that tumor cells invaded neighboring tissues and blood stream when primary tumors were at the microscopic sizes. These findings demonstrate that retinoblastoma metastasis occurs at the early stage and antiangiogenic drugs such as Vegf morpholino and sunitinib could potentially interfere with tumor invasiveness and metastasis. Thus, this orthotopic retinoblastoma model offers a new and unique opportunity to study the early events of tumor invasion, metastasis and drug responses. PMID:26169357

  19. Stochastic fluctuation induced the competition between extinction and recurrence in a model of tumor growth

    International Nuclear Information System (INIS)

    Li, Dongxi; Xu, Wei; Sun, Chunyan; Wang, Liang

    2012-01-01

    We investigate the phenomenon that stochastic fluctuation induced the competition between tumor extinction and recurrence in the model of tumor growth derived from the catalytic Michaelis–Menten reaction. We analyze the probability transitions between the extinction state and the state of the stable tumor by the Mean First Extinction Time (MFET) and Mean First Return Time (MFRT). It is found that the positional fluctuations hinder the transition, but the environmental fluctuations, to a certain level, facilitate the tumor extinction. The observed behavior could be used as prior information for the treatment of cancer. -- Highlights: ► Stochastic fluctuation induced the competition between extinction and recurrence. ► The probability transitions are investigated. ► The positional fluctuations hinder the transition. ► The environmental fluctuations, to a certain level, facilitate the tumor extinction. ► The observed behavior can be used as prior information for the treatment of cancer.

  20. The Pig as a Large Animal Model for Studying Anti-Tumor Immune Responses

    DEFF Research Database (Denmark)

    Overgaard, Nana Haahr

    The immune system plays a crucial role in cancer development and progression. Cancer immunoediting encompasses three phases: elimination, equilibrium, and escape; together, describing the complex interplay between tumor and immune cells. Specifically, the immune system both protects against cancer...... of autologous tumor cells, underlining the capacity of the Oncopig immune system to mount a cytotoxic anti-tumor response. Using the results from RNA-seq analysis, we propose a potential mechanism for in vivo inhibition of anti-tumor cytotoxicity based on elevated expression of the immunosuppressive genes IDO1...... support that the Oncopig provides a crucial platform for studying anti-tumor immune responses in a large in vivo system, although the model currently only allows preclinical testing of therapeutics against the early stages of cancer....

  1. Screening for supra-additive effects of cytotoxic drugs and gamma irradiation in an in vitro model for hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, B. [Ghent Univ. Hosptial, Nuclear Medicine Div., Ghent (Belgium)]. E-mail: bieke.lambert@Ugent.be; De Ridder, L. [Ghent Univ., Dept. of Histology, Anatomy, and Embryology, Ghent (Belgium); Slegers, G. [Ghent Univ., Dept. of Radiopharmacy, Ghent (Belgium); De Gelder, V. [Ghent Univ., Dept. of Medical Physics, Ghent (Belgium); Dierckx, R.A. [Ghent Univ. Hosptial, Nuclear Medicine Div., Ghent (Belgium); Thierens, H. [Ghent Univ., Dept. of Medical Physics, Ghent (Belgium)

    2004-02-01

    Hepatocellular carcinoma (HCC) is one of the most common malignancies in the world. A wide variety of treatment modalities is available for palliative therapy of HCC, although there is no strong evidence that these treatments can have a significant impact on survival. The aim of this work was to screen cytotoxic drugs relevant in the treatment of HCC for enhancement of the effect of irradiation in an in vitro model. As the majority of patients presenting with HCC suffer reduced liver function, attention was paid to low-dose effects of the cytotoxic drugs tested. To reflect this situation in vivo, multicellular tumor aggregates or 'spheroids' of HepG2 cells were cultured and exposed to gamma irradiation alone or in combination with cisplatin for 4 h, gemcitabin for 4 or 24 h, or 5-fluorouracil for 4 h. In one experiment, the spheroids were cultured for 4 weeks in multiwell plates that allowed adhesion. Measurement of two-dimensional spheroid outgrowth was made every week for each spheroid. This kind of growth depends on the proliferation and motility of the cells that form the spheroid. In a second experiment, toxicity was evaluated by comparative growth curves by means of a three-dimensional growth assay and by histology. Supra-additive effects lasting for 4 weeks were observed for all drugs tested in combination with a gamma irradiation of 10 Gy. (author)

  2. Microarray profiling shows distinct differences between primary tumors and commonly used preclinical models in hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Wang, Weining; Iyer, N. Gopalakrishna; Tay, Hsien Ts’ung; Wu, Yonghui; Lim, Tony K. H.; Zheng, Lin; Song, In Chin; Kwoh, Chee Keong; Huynh, Hung; Tan, Patrick O. B.; Chow, Pierce K. H.

    2015-01-01

    Despite advances in therapeutics, outcomes for hepatocellular carcinoma (HCC) remain poor and there is an urgent need for efficacious systemic therapy. Unfortunately, drugs that are successful in preclinical studies often fail in the clinical setting, and we hypothesize that this is due to functional differences between primary tumors and commonly used preclinical models. In this study, we attempt to answer this question by comparing tumor morphology and gene expression profiles between primary tumors, xenografts and HCC cell lines. Hep G2 cell lines and tumor cells from patient tumor explants were subcutaneously (ectopically) injected into the flank and orthotopically into liver parenchyma of Mus Musculus SCID mice. The mice were euthanized after two weeks. RNA was extracted from the tumors, and gene expression profiling was performed using the Gene Chip Human Genome U133 Plus 2.0. Principal component analyses (PCA) and construction of dendrograms were conducted using Partek genomics suite. PCA showed that the commonly used HepG2 cell line model and its xenograft counterparts were vastly different from all fresh primary tumors. Expression profiles of primary tumors were also significantly divergent from their counterpart patient-derived xenograft (PDX) models, regardless of the site of implantation. Xenografts from the same primary tumors were more likely to cluster together regardless of site of implantation, although heat maps showed distinct differences in gene expression profiles between orthotopic and ectopic models. The data presented here challenges the utility of routinely used preclinical models. Models using HepG2 were vastly different from primary tumors and PDXs, suggesting that this is not clinically representative. Surprisingly, site of implantation (orthotopic versus ectopic) resulted in limited impact on gene expression profiles, and in both scenarios xenografts differed significantly from the original primary tumors, challenging the long

  3. Towards an integrative computational model for simulating tumor growth and response to radiation therapy

    Science.gov (United States)

    Marrero, Carlos Sosa; Aubert, Vivien; Ciferri, Nicolas; Hernández, Alfredo; de Crevoisier, Renaud; Acosta, Oscar

    2017-11-01

    Understanding the response to irradiation in cancer radiotherapy (RT) may help devising new strategies with improved tumor local control. Computational models may allow to unravel the underlying radiosensitive mechanisms intervening in the dose-response relationship. By using extensive simulations a wide range of parameters may be evaluated providing insights on tumor response thus generating useful data to plan modified treatments. We propose in this paper a computational model of tumor growth and radiation response which allows to simulate a whole RT protocol. Proliferation of tumor cells, cell life-cycle, oxygen diffusion, radiosensitivity, RT response and resorption of killed cells were implemented in a multiscale framework. The model was developed in C++, using the Multi-formalism Modeling and Simulation Library (M2SL). Radiosensitivity parameters extracted from literature enabled us to simulate in a regular grid (voxel-wise) a prostate cell tissue. Histopathological specimens with different aggressiveness levels extracted from patients after prostatectomy were used to initialize in silico simulations. Results on tumor growth exhibit a good agreement with data from in vitro studies. Moreover, standard fractionation of 2 Gy/fraction, with a total dose of 80 Gy as a real RT treatment was applied with varying radiosensitivity and oxygen diffusion parameters. As expected, the high influence of these parameters was observed by measuring the percentage of survival tumor cell after RT. This work paves the way to further models allowing to simulate increased doses in modified hypofractionated schemes and to develop new patient-specific combined therapies.

  4. More Reasonable Animal Model for Study the Effect of Pneumoperitoneum on Abdominal Tumor Cells

    Science.gov (United States)

    Qijun, Lv; Jiang, Du; Chongshu, Wang

    2018-01-27

    Background: Many animal experimental studies showed that abdominal tumor cells will be widely spread during laparoscopic treatment and grow into metastases. These results are different from clinical observations. There is a hypothesis that too much tumor cells was injected in the animals lead to the results of theses bias. We aim to learn the difference of abdominal cavity volume between human body and the nude mice and to determine reasonable amount of tumor cells in the animal experiments. Methods: The insufflated CO2 volume which represents the capacity of the abdominal cavity was recorded during laparoscopic process in 212 patients and 20 nude mice respectively, the relative volume of nude mice and human body was calculated.Based on data from the literature and this study , the amount of tumor cells in the animal experiments was determined.According to these data, we set up a new animal model and a traditional one respectively,and compared the rate of successful modeling and tumor formation between two animal models. Results: The intraperitoneal volumes of humans and nude mice were 3.01±0.36 L and 0.011±0.001 L respectively.The number of tumor cells that be uesd in animal should be approximately 0.26×105 in terms of known data in human beings.Compared with the traditional animal model which formed a large number of intraperitoneal tumor metastasis, the new animal model was shows more moderately,and the rate of successful modeling was similar. Conclusion: In animal experiments, to simulate the clinical situation, about 0.26×105 tumor cells should be inject in peritoneal cavity of the nude mice. Creative Commons Attribution License

  5. Predicting anti-tumor effect of deoxypodophyllotoxin in NCI-H460 tumor-bearing mice based on in vitro pharmacodynamics and physiologically based pharmacokinetic-pharmacodynamic model.

    Science.gov (United States)

    Chen, Yang; Zhao, Kaijing; Liu, Fei; Li, Ying; Zhong, Zeyu; Hong, Shijin; Liu, Xiaodong; Liu, Li

    2018-04-04

    Anti-tumor evaluation in tumor-bearing mouse is time- and energy-consuming. We aimed to investigate whether in vivo anti-tumor efficacy could be predicted based on in vitro pharmacodynamics using deoxypodophyllotoxin (DPT), a developing anti-tumor candidate, as a model compound. Proliferation kinetics of monolayer cultivated NCI-H460 cells under various DPT concentrations was quantitatively investigated accompanied by calibration curves. Koch's two-phase natural growth model combined with sigmoid Emax model, i.e. dM/dt=2λ 0 λ 1 M/(λ 1 +2λ 0 M)-EmaxC γ /(EC 50 γ +C γ )·M, was introduced to describe cell proliferation (M) against time under DPT treatment (C). Estimated in vitro pharmacodynamic parameters were: EC 50 , 8.97 nM; Emax, 0.820 day -1 and γ, 7.13. A physiologically based pharmacokinetic (PBPK) model including tumor compartment was introduced, which could predict DPT disposition in plasma, tumor tissue and main normal tissues of NCI-H460 tumor-bearing mice following single dose. In vivo pharmacodynamic model and parameters were assumed the same as in vitro ones, and linked with simulated tumor pharmacokinetic profiles by PBPK model, to build a physiologically based pharmacokinetic-pharmacodynamic (PBPK-PD) model. After estimating natural growth parameters (λ 0 and λ 1 ), we desirably predicted the tumor growth in NCI-H460 tumor-bearing mice during multi-dose DPT treatment, both in this study and literature, by the PBPK-PD model. The model was further successfully applied to predict tumor growth in SGC-7901 tumor-bearing mice. These data indicated that in vivo anti-tumor efficacy might be predicted based on in vitro cytotoxic assays via PBPK-PD model approach. The approach was demonstrated reasonable and applicable, which might facilitate and accelerate anti-cancer candidate screening and dose regimen design in drug discovery process. The American Society for Pharmacology and Experimental Therapeutics.

  6. Monitoring Prostate Tumor Growth in an Orthotopic Mouse Model Using Three-Dimensional Ultrasound Imaging Technique

    Directory of Open Access Journals (Sweden)

    Jie Ni

    2016-02-01

    Full Text Available Prostate cancer (CaP is the most commonly diagnosed and the second leading cause of death from cancer in males in USA. Prostate orthotopic mouse model has been widely used to study human CaP in preclinical settings. Measurement of changes in tumor size obtained from noninvasive diagnostic images is a standard method for monitoring responses to anticancer modalities. This article reports for the first time the usage of a three-dimensional (3D ultrasound system equipped with photoacoustic (PA imaging in monitoring longitudinal prostate tumor growth in a PC-3 orthotopic NODSCID mouse model (n = 8. Two-dimensional and 3D modes of ultrasound show great ability in accurately depicting the size and shape of prostate tumors. PA function on two-dimensional and 3D images showed average oxygen saturation and average hemoglobin concentration of the tumor. Results showed a good fit in representative exponential tumor growth curves (n = 3; r2 = 0.948, 0.955, and 0.953, respectively and a good correlation of tumor volume measurements performed in vivo with autopsy (n = 8, r = 0.95, P < .001. The application of 3D ultrasound imaging proved to be a useful imaging modality in monitoring tumor growth in an orthotopic mouse model, with advantages such as high contrast, uncomplicated protocols, economical equipment, and nonharmfulness to animals. PA mode also enabled display of blood oxygenation surrounding the tumor and tumor vasculature and angiogenesis, making 3D ultrasound imaging an ideal tool for preclinical cancer research.

  7. Effects of irradiation and cisplatin on human glioma spheroids: inhibition of cell proliferation and cell migration

    NARCIS (Netherlands)

    Fehlauer, Fabian; Muench, Martina; Rades, Dirk; Stalpers, Lukas J. A.; Leenstra, Sieger; van der Valk, Paul; Slotman, Ben; Smid, Ernst J.; Sminia, Peter

    2005-01-01

    Investigation of cell migration and proliferation of human glioma cell line spheroids (CLS) and evaluation of morphology, apoptosis, and immunohistochemical expression of MIB-1, p53, and p21 of organotypic muticellular spheroids (OMS) following cisplatin (CDDP) and irradiation (RT). Spheroids of the

  8. A theoretical model for the effects of reduced hemoglobin-oxygen affinity on tumor oxygenation

    International Nuclear Information System (INIS)

    Kavanagh, Brian D.; Secomb, Timothy W.; Hsu, Richard; Lin, P.-S.; Venitz, Jurgen; Dewhirst, Mark W.

    2002-01-01

    Purpose: To develop a theoretical model for oxygen delivery to tumors, and to use the model to simulate the effects of changing the affinity of hemoglobin for oxygen on tumor oxygenation. Methods and Materials: Hemoglobin affinity is expressed in terms of P 50 , the partial pressure of oxygen (Po 2 ) at half saturation. Effects of changing P 50 on arterial Po 2 are predicted using an effective vessel approach to describe diffusive oxygen transport in the lungs, assuming fixed systemic oxygen demand and fixed blood flow rate. The decline in oxygen content of blood as it flows through normal tissue before entering the tumor region is assumed fixed. The hypoxic fraction of the tumor region is predicted using a three-dimensional simulation of diffusion from a network of vessels whose geometry is derived from observations of tumor microvasculature in the rat. Results: In air-breathing rats, predicted hypoxic fraction decreases with moderate increases in P 50 , but increases with further increases of P 50 , in agreement with previous experimental results. In rats breathing hyperoxic gases, and in humans breathing either normoxic or hyperoxic gases, increased P 50 is predicted to improve tumor oxygenation. Conclusions: The results support the administration of synthetic agents to increase P 50 during radiation treatment of tumors

  9. 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.

  10. 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.

  11. Radiotherapy planning for glioblastoma based on a tumor growth model: implications for spatial dose redistribution

    International Nuclear Information System (INIS)

    Unkelbach, Jan; Dittmann, Florian; Shih, Helen A; Menze, Bjoern H; Ayache, Nicholas; Konukoglu, Ender

    2014-01-01

    Gliomas differ from many other tumors as they grow infiltratively into the brain parenchyma rather than forming a solid tumor mass with a well-defined boundary. Tumor cells can be found several centimeters away from the central tumor mass that is visible using current imaging techniques. The infiltrative growth characteristics of gliomas question the concept of a radiotherapy target volume that is irradiated to a homogeneous dose—the standard in current clinical practice. We discuss the use of the Fisher–Kolmogorov glioma growth model in radiotherapy treatment planning. The phenomenological tumor growth model assumes that tumor cells proliferate locally and migrate into neighboring brain tissue, which is mathematically described via a partial differential equation for the spatio-temporal evolution of the tumor cell density. In this model, the tumor cell density drops approximately exponentially with distance from the visible gross tumor volume, which is quantified by the infiltration length, a parameter describing the distance at which the tumor cell density drops by a factor of e. This paper discusses the implications for the prescribed dose distribution in the periphery of the tumor. In the context of the exponential cell kill model, an exponential fall-off of the cell density suggests a linear fall-off of the prescription dose with distance. We introduce the dose fall-off rate, which quantifies the steepness of the prescription dose fall-off in units of Gy mm −1 . It is shown that the dose fall-off rate is given by the inverse of the product of radiosensitivity and infiltration length. For an infiltration length of 3 mm and a surviving fraction of 50% at 2 Gy, this suggests a dose fall-off of approximately 1 Gy mm −1 . The concept is illustrated for two glioblastoma patients by optimizing intensity-modulated radiotherapy plans. The dose fall-off rate concept reflects the idea that infiltrating gliomas lack a defined boundary and are characterized by a

  12. Biological models in vivo for boron neutronic capture studies as tumors therapy

    International Nuclear Information System (INIS)

    Kreimann, Erica L.; Dagrosa, Maria A.; Schwint, Amanda E.; Itoiz, Maria E.; Pisarev, Mario A.; Farias, Silvia S.; Garavaglia, Ricardo N.; Batistoni, Daniel A.

    1999-01-01

    The use of experimental models for Boron Neutronic Capture studies as Tumors Therapy have as two main objectives: 1) To contribute to the basic knowledge of the biological mechanisms involved to increase the method therapeutical advantage, and 2) To explore the possible application of this therapeutic method to other pathologies. In this frame it was studied the carcinogenesis model of hamster cheek pouch, a type of human buccal cancer. Biodistribution studies of boron compound were performed in tumor, blood and in different precancerous and normal tissues as well as BNCT studies. Results validated this method for BNCT studies and show the capacity of the oral mucosa tumors of selectively concentrate the boron compound, showing a deleterious clear effect on the tumor after 24 hours with BNCT treatment. (author)

  13. An orthotopic bladder tumor model and the evaluation of intravesical saRNA treatment.

    Science.gov (United States)

    Kang, Moo Rim; Yang, Glen; Charisse, Klaus; Epstein-Barash, Hila; Manoharan, Muthiah; Li, Long-Cheng

    2012-07-28

    We present a novel method for treating bladder cancer with intravesically delivered small activating RNA (saRNA) in an orthotopic xenograft mouse bladder tumor model. The mouse model is established by urethral catheterization under inhaled general anesthetic. Chemical burn is then introduced to the bladder mucosa using intravesical silver nitrate solution to disrupt the bladder glycosaminoglycan layer and allows cells to attach. Following several washes with sterile water, human bladder cancer KU-7-luc2-GFP cells are instilled through the catheter into the bladder to dwell for 2 hours. Subsequent growth of bladder tumors is confirmed and monitored by in vivo bladder ultrasound and bioluminescent imaging. The tumors are then treated intravesically with saRNA formulated in lipid nanoparticles (LNPs). Tumor growth is monitored with ultrasound and bioluminescence. All steps of this procedure are demonstrated in the accompanying video.

  14. A simulation model investigating the impact of tumor volume doubling time and mammographic tumor detectability on screening outcomes in women aged 40-49 years.

    Science.gov (United States)

    Bailey, Stephanie L; Sigal, Bronislava M; Plevritis, Sylvia K

    2010-08-18

    Compared with women aged 50-69 years, the lower sensitivity of mammographic screening in women aged 40-49 years is largely attributed to the lower mammographic tumor detectability and faster tumor growth in the younger women. We used a Monte Carlo simulation model of breast cancer screening by age to estimate the median tumor size detectable on a mammogram and the mean tumor volume doubling time. The estimates were calculated by calibrating the predicted breast cancer incidence rates to the actual rates from the Surveillance, Epidemiology, and End Results (SEER) database and the predicted distributions of screen-detected tumor sizes to the actual distributions obtained from the Breast Cancer Surveillance Consortium (BCSC). The calibrated parameters were used to estimate the relative impact of lower mammographic tumor detectability vs faster tumor volume doubling time on the poorer screening outcomes in younger women compared with older women. Mammography screening outcomes included sensitivity, mean tumor size at detection, lifetime gained, and breast cancer mortality. In addition, the relationship between screening sensitivity and breast cancer mortality was investigated as a function of tumor volume doubling time, mammographic tumor detectability, and screening interval. Lowered mammographic tumor detectability accounted for 79% and faster tumor volume doubling time accounted for 21% of the poorer sensitivity of mammography screening in younger women compared with older women. The relative contributions were similar when the impact of screening was evaluated in terms of mean tumor size at detection, lifetime gained, and breast cancer mortality. Screening sensitivity and breast cancer mortality reduction attributable to screening were almost linearly related when comparing annual or biennial screening with no screening. However, when comparing annual with biennial screening, the greatest reduction in breast cancer mortality attributable to screening did not

  15. Inhibition of tumor growth in a glioma model treated with boron neutron capture therapy

    International Nuclear Information System (INIS)

    Goodman, J.H.; McGregor, J.M.; Clendenon, N.R.; Gahbauer, R.A.; Barth, R.F.; Soloway, A.H.; Fairchild, R.G.

    1990-01-01

    This investigation attempts to determine whether increased survival time seen when the F98 glioma model is treated with boron neutron capture therapy (BNCT) is a result of inhibition of tumor growth caused by radiation-induced alterations in endothelial cells and normal tissue components. This indirect effect of radiation has been called the tumor bed effect. A series of tumor-bearing rats was studied, using a standardized investigational BNCT protocol consisting of 50 mg/kg of Na2B12H11SH injected intravenously 14 to 17 hours before neutron irradiation at 4 x 10(12) n/cm2. Ten rats, serving as controls, received no treatment either before or after tumor implantation. A second group of 10 rats was treated with BNCT 4 days before tumor implantation; these animals received no further treatment. The remaining group of 10 rats received no pretreatment but was treated with BNCT 10 days after implantation. Histological and ultrastructural analyses were performed in 2 animals from each group 17 days after implantation. Survival times of the untreated control animals (mean, 25.8 days) did not differ statistically from the survival times of the rats in the pretreated group (mean, 25.5 days). The rats treated with BNCT after implantation survived significantly longer (P less than 0.02; mean, 33.2 days) than the controls and the preirradiated animals. Tumor size indices calculated from measurements taken at the time of death were similar in all groups. These results indicate that, with this tumor model, BNCT does not cause a tumor bed effect in cerebral tissue. The therapeutic gains observed with BNCT result from direct effects on tumor cells or on the peritumoral neovascularity

  16. Impact of MR-guided boiling histotripsy in distinct murine tumor models.

    Science.gov (United States)

    Hoogenboom, Martijn; Eikelenboom, Dylan C; van den Bijgaart, Renske J E; Heerschap, Arend; Wesseling, Pieter; den Brok, Martijn H; Fütterer, Jurgen J; Adema, Gosse J

    2017-09-01

    Interest in mechanical high intensity focused ultrasound (HIFU) ablation is rapidly growing. Boiling histotripsy (BH) is applied for mechanical fragmentation of soft tissue into submicron fragments with limited temperature increase using the shock wave and cavitation effects of HIFU. Research on BH has been largely limited to ex vivo experiments. As a consequence, the in vivo pathology after BH treatment and the relation to preexistent tissue characteristics are not well understood. This study reports on in vivo MR guided BH treatment, either with 100 or 200 pulses per focal spot, in three different subcutaneous mouse tumor models: a soft-tissue melanoma (B16OVA), a compact growing thymoma (EL4), and a highly vascularized neuroblastoma (9464D). Extensive treatment evaluation was performed using MR imaging followed by histopathology 2h after treatment. T2 weighted MRI allowed direct in vivo visualization of the BH lesions in all tumor models. The 100-pulse treated area in the B16OVA tumors was larger than the predicted treatment volume (500±10%). For the more compact growing EL4 and 9464D tumors this was 95±13% and 55±33%, respectively. Histopathology after the 100-pulse treatment revealed completely disintegrated lesions in the treated area with sharp borders in the compact EL4 and 9464D tumors, while for B16OVA tumors the lesion contained a mixture of discohesive (partly viable) clusters of cells, micro-vessel remainings, and tumor cell debris. The treatment of B16OVA with 200 pulses increased the fragmentation of tumor tissue. In all tumor types only micro-hemorrhages were detected after ablation (slightly higher after 200-pulse treatment for the highly vascularized 9464D tumors). Collagen staining revealed that the collagen fibers were to a greater or lesser extent still intact and partly clotted together near the lesion border in all tumor models. In conclusion, this study reveals effective mechanical fragmentation of different tumor types using BH without

  17. Analyses of tumor-suppressor genes in germline mouse models of cancer.

    Science.gov (United States)

    Wang, Jingqiang; Abate-Shen, Cory

    2014-08-01

    Tumor-suppressor genes are critical regulators of growth and functioning of cells, whose loss of function contributes to tumorigenesis. Accordingly, analyses of the consequences of their loss of function in genetically engineered mouse models have provided important insights into mechanisms of human cancer, as well as resources for preclinical analyses and biomarker discovery. Nowadays, most investigations of genetically engineered mouse models of tumor-suppressor function use conditional or inducible alleles, which enable analyses in specific cancer (tissue) types and overcome the consequences of embryonic lethality of germline loss of function of essential tumor-suppressor genes. However, historically, analyses of genetically engineered mouse models based on germline loss of function of tumor-suppressor genes were very important as these early studies established the principle that loss of function could be studied in mouse cancer models and also enabled analyses of these essential genes in an organismal context. Although the cancer phenotypes of these early germline models did not always recapitulate the expected phenotypes in human cancer, these models provided the essential foundation for the more sophisticated conditional and inducible models that are currently in use. Here, we describe these "first-generation" germline models of loss of function models, focusing on the important lessons learned from their analyses, which helped in the design and analyses of "next-generation" genetically engineered mouse models. © 2014 Cold Spring Harbor Laboratory Press.

  18. A mechanistic tumor penetration model to guide antibody drug conjugate design.

    Directory of Open Access Journals (Sweden)

    Christina Vasalou

    Full Text Available Antibody drug conjugates (ADCs represent novel anti-cancer modalities engineered to specifically target and kill tumor cells expressing corresponding antigens. Due to their large size and their complex kinetics, these therapeutic agents often face heterogeneous distributions in tumors, leading to large untargeted regions that escape therapy. We present a modeling framework which includes the systemic distribution, vascular permeability, interstitial transport, as well as binding and payload release kinetics of ADC-therapeutic agents in mouse xenografts. We focused, in particular, on receptor dynamics such as endocytic trafficking mechanisms within cancer cells, to simulate their impact on tumor mass shrinkage upon ADC administration. Our model identified undesirable tumor properties that can impair ADC tissue homogeneity, further compromising ADC success, and explored ADC design optimization scenarios to counteract upon such unfavorable intrinsic tumor tissue attributes. We further demonstrated the profound impact of cytotoxic payload release mechanisms and the role of bystander killing effects on tumor shrinkage. This model platform affords a customizable simulation environment which can aid with experimental data interpretation and the design of ADC therapeutic treatments.

  19. A mouse model of luciferase-transfected stromal cells of giant cell tumor of bone.

    Science.gov (United States)

    Lau, Carol P Y; Wong, Kwok Chuen; Huang, Lin; Li, Gang; Tsui, Stephen K W; Kumta, Shekhar Madhukar

    2015-11-01

    A major barrier towards the study of the effects of drugs on Giant Cell Tumor of Bone (GCT) has been the lack of an animal model. In this study, we created an animal model in which GCT stromal cells survived and functioned as proliferating neoplastic cells. A proliferative cell line of GCT stromal cells was used to create a stable and luciferase-transduced cell line, Luc-G33. The cell line was characterized and was found that there were no significant differences on cell proliferation rate and recruitment of monocytes when compared with the wild type GCT stromal cells. We delivered the Luc-G33 cells either subcutaneously on the back or to the tibiae of the nude mice. The presence of viable Luc-G33 cells was assessed using real-time live imaging by the IVIS 200 bioluminescent imaging (BLI) system. The tumor cells initially propagated and remained viable on site for 7 weeks in the subcutaneous tumor model. We also tested in vivo antitumor effects of Zoledronate (ZOL) and Geranylgeranyl transferase-I inhibitor (GGTI-298) alone or their combinations in Luc-G33-transplanted nude mice. ZOL alone at 400 µg/kg and the co-treatment of ZOL at 400 µg/kg and GGTI-298 at 1.16 mg/kg reduced tumor cell viability in the model. Furthermore, the anti-tumor effects by ZOL, GGTI-298 and the co-treatment in subcutaneous tumor model were also confirmed by immunohistochemical (IHC) staining. In conclusion, we established a nude mice model of GCT stromal cells which allows non-invasive, real-time assessments of tumor development and testing the in vivo effects of different adjuvants for treating GCT.

  20. A volume-equivalent spherical necrosis-tumor-normal liver model for estimating absorbed dose in yttrium-90 microsphere therapy.

    Science.gov (United States)

    Wu, Chin-Hui; Liao, Yi-Jen; Lin, Tzung-Yi; Chen, Yu-Cheng; Sun, Shung-Shung; Liu, Yen-Wan Hsueh; Hsu, Shih-Ming

    2016-11-01

    Primary hepatocellular carcinoma and metastatic liver tumors are highly malignant tumors in Asia. The incidence of fatal liver cancer is also increasing in the United States. The aim of this study was to establish a spherical tumor model and determine its accuracy in predicting the absorbed dose in yttrium-90 (Y-90) microsphere therapy for liver cancer. Liver morphology can be approximated by a spherical model comprising three concentric regions representing necrotic, tumor, and normal liver tissues. The volumes of these three regions represent those in the actual liver. A spherical tumor model was proposed to calculate the absorbed fractions in the spherical tumor, necrotic, and normal tissue regions. The THORplan treatment planning system and Monte Carlo N-particle extended codes were used for this spherical tumor model. Using the volume-equivalent method, a spherical tumor model was created to calculate the total absorbed fraction [under different tumor-to-healthy-liver ratios (TLRs)]. The patient-specific model (THORplan) results were used to verify the spherical tumor model results. The results for both the Y-90 spectrum and the Y-90 mean energy indicated that the absorbed fraction was a function of the tumor radius and mass. The absorbed fraction increased with tumor radius. The total absorbed fractions calculated using the spherical tumor model for necrotic, liver tumor, and normal liver tissues were in good agreement with the THORplan results, with differences of less than 3% for TLRs of 2-5. The results for the effect of TLR indicate that for the same tumor configuration, the total absorbed fraction decreased with increasing TLR; for the same shell tumor thickness and TLR, the total absorbed fraction was approximately constant; and for tumors with the same radius, the total fraction absorbed by the tumor increased with the shell thickness. The results from spherical tumor models with different tumor-to-healthy-liver ratios were highly consistent with the

  1. Modelling Tumor-induced Angiogenesis: Combination of Stochastic Sprout Spacing and Sprout Progression

    Directory of Open Access Journals (Sweden)

    Hosseini F.

    2017-09-01

    Full Text Available Background: Angiogenesis initiated by cancerous cells is the process by which new blood vessels are formed to enhance oxygenation and growth of tumor. Objective: In this paper, we present a new multiscale mathematical model for the formation of a vascular network in tumor angiogenesis process. Methods: Our model couples an improved sprout spacing model as a stochastic mathematical model of sprouting along an existing parent blood vessel, with a mathematical model of sprout progression in the extracellular matrix (ECM in response to some tumor angiogenic factors (TAFs. We perform simulations of the siting of capillary sprouts on an existing blood vessel using finite difference approximation of the dynamic equations of some angiogenesis activators and inhibitors. Angiogenesis activators are chemicals secreted by hypoxic tumor cells for initiating angiogenesis, and inhibitors of the angiogenesis are chemicals that are produced around every new sprout during tumor angiogenesis to inhibit the formation of further sprouts as a feedback of sprouting in angiogenesis. Moreover, for modelling sprout progression in ECM, we use three equations for the motility of endothelial cells at the tip of the activated sprouts, the consumption of TAF and the production and uptake of Fibronectin by endothelial cells. Results: Coupling these two basic models not only does provide a better time estimation of angiogenesis process, but also it is more compatible with reality. Conclusion: This model can be used to provide basic information for angiogenesis in the related studies. Related simulations can estimate the position and number of sprouts along parent blood vessel during the initial steps of angiogenesis and models the process of sprout progression in ECM until they vascularize a tumor.

  2. Void nucleation in spheroidized steels during tensile deformation

    International Nuclear Information System (INIS)

    Fisher, J.R. Jr.

    1980-04-01

    An investigation was conducted to determine the effects of various mechanical and material parameters on void formation at cementite particles in axisymmetric tensile specimens of spheroidized plain carbon steels. Desired microstructures for each of three steel types were obtained. Observations of void morphology with respect to various microstructural features were made using optical and scanning electron microscopy

  3. Sulphur, zinc and carbon in the Sculptor dwarf spheroidal galaxy

    NARCIS (Netherlands)

    Skúladóttir, Ása

    2016-01-01

    The Sculptor dwarf spheroidal galaxy is a Milky Way satellite with predominantly old stellar population, and therefore the ideal target to study early chemical evolution. The chemical abundances of photospheres of stars reveal the composition of their birth environment; studying stars of different

  4. Chemical Evolution of Mn in Three Dwarf Spheroidal Galaxies

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... ... SNeIa and CCSNe, we studied Mn evolution for three local dwarf spheroidal galaxies (dSphs), considering the detailed SNe yield and explosion rates for different types of progenitors. The results can explain the main observation ofMn abundance for tens stars in those dSphs, and give some constraints ...

  5. Void nucleation in spheroidized steels during tensile deformation

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, Jr, J R

    1980-04-01

    An investigation was conducted to determine the effects of various mechanical and material parameters on void formation at cementite particles in axisymmetric tensile specimens of spheroidized plain carbon steels. Desired microstructures for each of three steel types were obtained. Observations of void morphology with respect to various microstructural features were made using optical and scanning electron microscopy.

  6. The dynamical and chemical evolution of dwarf spheroidal galaxies

    NARCIS (Netherlands)

    Revaz, Y.; Jablonka, P.; Sawala, T.; Hill, V.; Letarte, B.; Irwin, M.; Battaglia, G.; Helmi, A.; Shetrone, M. D.; Tolstoy, E.; Venn, K. A.

    We present a large sample of fully self-consistent hydrodynamical Nbody/Tree-SPH simulations of isolated dwarf spheroidal galaxies (dSphs). It has enabled us to identify the key physical parameters and mechanisms at the origin of the observed variety in the Local Group dSph properties. The initial

  7. Zinc abundances in the Sculptor dwarf spheroidal galaxy

    NARCIS (Netherlands)

    Skúladóttir, Á.; Tolstoy, E.; Salvadori, S.; Hill, V.; Pettini, M.

    2017-01-01

    From ESO VLT/FLAMES/GIRAFFE spectra, abundance measurements of Zn have been made in ≈100 individual red giant branch (RGB) stars in the Sculptor dwarf spheroidal galaxy. This is the largest sample of individual Zn abundance measurements within a stellar system beyond the Milky Way. In the observed

  8. Optical properties of spherical and oblate spheroidal gold shell colloids

    NARCIS (Netherlands)

    Penninkhof, J.J.; Moroz, A.; van Blaaderen, A.; Polman, A.

    2008-01-01

    The surface plasmon modes of spherical and oblate spheroidal core−shell colloids composed of a 312 nm diameter silica core and a 20 nm thick Au shell are investigated. Large arrays of uniaxially aligned core−shell colloids with size aspect ratios ranging from 1.0 to 1.7 are fabricated using a novel

  9. Numerical simulations of the metallicity distribution in dwarf spheroidal galaxies

    NARCIS (Netherlands)

    Ripamonti, E.; Tolstoy, E.; Helmi, A.; Battaglia, G.; Abel, T.

    2006-01-01

    Abstract: Recent observations show that the number of stars with very low metallicities in the dwarf spheroidal satellites of the Milky Way is low, despite the low average metallicities of stars in these systems. We undertake numerical simulations of star formation and metal enrichment of dwarf

  10. The mass content of the Sculptor dwarf spheroidal galaxy

    NARCIS (Netherlands)

    Battaglia, G.; Helmi, A.; Tolstoy, E.; Irwin, M.; Andersen, J; BlandHawthorn, J; Nordstrom, B

    2009-01-01

    We present a new determination of the mass content of the Sculptor dwarf spheroidal galaxy, based on a novel approach which takes into account the two distinct stellar populations present in this galaxy. This method helps to partially break the well-known mass-anisotropy degeneracy present in the

  11. Cryopreservation of organotypic multicellular spheroids from human gliomas

    NARCIS (Netherlands)

    Kaaijk, P.; van den Berg, F.; van Amstel, P.; Troost, D.

    1996-01-01

    Fresh human glioma tissue can be cultured on agarose to form organotypic multicellular spheroids (OMS). The major advantage of OMS is the preservation of the cellular heterogeneity and the tumour architecture, which is lost in conventional monolayer cultures. The present study was undertaken to

  12. Estimation of scattering from a moist rough surface with spheroidal ...

    Indian Academy of Sciences (India)

    Administrator

    less than 5⋅5% of the magnetic wavelength. We empha- size that the surface deviation is responsible for scattering at a given electromagnetic wavelength. 2. Theoretical consideration (basic theory). We consider a horizontally rough surface with slight per- centage of moisture (2–4⋅5%) with spheroidal dust parti- cles.

  13. The dwarf spheroidal galaxies around the milky way

    NARCIS (Netherlands)

    Tolstoy, E.; Battaglia, G.; Helmi, A.; Irwin, M. J.; Hill, V.; Vallenari, A; Tantalo, R; Portinari, L; Moretti, A

    2007-01-01

    We review the progress of ESO/WFI Imaging and VLT/FLAMES spectroscopy of large numbers of individual stars in nearby dwarf spheroidal galaxies by the Dwarf Abundances and Radial-velocities Team (DART). These observations have allowed us to show that neither the kinematics nor the abundance nor the

  14. Effects of hypoxia on expression of a panel of stem cell and chemoresistance markers in glioblastoma-derived spheroids

    DEFF Research Database (Denmark)

    Kolenda, Jesper; Jensen, Stine Skov; Aaberg-Jessen, Charlotte

    2011-01-01

    ). Spheroids were formed in 21% and 1% O(2) in serum-free medium. The immunohistochemical panel included hypoxia (HIF-1α, HIF-2α), proliferation (Ki-67), and stem cell markers (CD133, podoplanin, Bmi-1, nestin, Sox-2) as well as markers related to chemoresistance (MGMT, TIMP-1, Lamp-1, MRP1, MDR-1....... Expression of stem cell markers CD133, podoplanin, Bmi-1, and nestin was increased in hypoxia, whereas Sox-2 was increased in SJ-1 only. TIMP-1 and Lamp-1 were increased in both SJ-1 and U87. In conclusion, the tumor cell phenotype related to stemness, and thereby potentially to chemoresistance, seems...

  15. Classical mathematical models for description and prediction of experimental tumor growth.

    Science.gov (United States)

    Benzekry, Sébastien; Lamont, Clare; Beheshti, Afshin; Tracz, Amanda; Ebos, John M L; Hlatky, Lynn; Hahnfeldt, Philip

    2014-08-01

    Despite internal complexity, tumor growth kinetics follow relatively simple laws that can be expressed as mathematical models. To explore this further, quantitative analysis of the most classical of these were performed. The models were assessed against data from two in vivo experimental systems: an ectopic syngeneic tumor (Lewis lung carcinoma) and an orthotopically xenografted human breast carcinoma. The goals were threefold: 1) to determine a statistical model for description of the measurement error, 2) to establish the descriptive power of each model, using several goodness-of-fit metrics and a study of parametric identifiability, and 3) to assess the models' ability to forecast future tumor growth. The models included in the study comprised the exponential, exponential-linear, power law, Gompertz, logistic, generalized logistic, von Bertalanffy and a model with dynamic carrying capacity. For the breast data, the dynamics were best captured by the Gompertz and exponential-linear models. The latter also exhibited the highest predictive power, with excellent prediction scores (≥80%) extending out as far as 12 days in the future. For the lung data, the Gompertz and power law models provided the most parsimonious and parametrically identifiable description. However, not one of the models was able to achieve a substantial prediction rate (≥70%) beyond the next day data point. In this context, adjunction of a priori information on the parameter distribution led to considerable improvement. For instance, forecast success rates went from 14.9% to 62.7% when using the power law model to predict the full future tumor growth curves, using just three data points. These results not only have important implications for biological theories of tumor growth and the use of mathematical modeling in preclinical anti-cancer drug investigations, but also may assist in defining how mathematical models could serve as potential prognostic tools in the clinic.

  16. Classical mathematical models for description and prediction of experimental tumor growth.

    Directory of Open Access Journals (Sweden)

    Sébastien Benzekry

    2014-08-01

    Full Text Available Despite internal complexity, tumor growth kinetics follow relatively simple laws that can be expressed as mathematical models. To explore this further, quantitative analysis of the most classical of these were performed. The models were assessed against data from two in vivo experimental systems: an ectopic syngeneic tumor (Lewis lung carcinoma and an orthotopically xenografted human breast carcinoma. The goals were threefold: 1 to determine a statistical model for description of the measurement error, 2 to establish the descriptive power of each model, using several goodness-of-fit metrics and a study of parametric identifiability, and 3 to assess the models' ability to forecast future tumor growth. The models included in the study comprised the exponential, exponential-linear, power law, Gompertz, logistic, generalized logistic, von Bertalanffy and a model with dynamic carrying capacity. For the breast data, the dynamics were best captured by the Gompertz and exponential-linear models. The latter also exhibited the highest predictive power, with excellent prediction scores (≥80% extending out as far as 12 days in the future. For the lung data, the Gompertz and power law models provided the most parsimonious and parametrically identifiable description. However, not one of the models was able to achieve a substantial prediction rate (≥70% beyond the next day data point. In this context, adjunction of a priori information on the parameter distribution led to considerable improvement. For instance, forecast success rates went from 14.9% to 62.7% when using the power law model to predict the full future tumor growth curves, using just three data points. These results not only have important implications for biological theories of tumor growth and the use of mathematical modeling in preclinical anti-cancer drug investigations, but also may assist in defining how mathematical models could serve as potential prognostic tools in the clinic.

  17. State-Dependent Impulsive Control Strategies for a Tumor-Immune Model

    Directory of Open Access Journals (Sweden)

    Kwang Su Kim

    2016-01-01

    Full Text Available Controlling the number of tumor cells leads us to expect more efficient strategies for treatment of tumor. Towards this goal, a tumor-immune model with state-dependent impulsive treatments is established. This model may give an efficient treatment schedule to control tumor’s abnormal growth. By using the Poincaré map and analogue of Poincaré criterion, some conditions for the existence and stability of a positive order-1 periodic solution of this model are obtained. Moreover, we carry out numerical simulations to illustrate the feasibility of our main results and compare fixed-time impulsive treatment effects with state-dependent impulsive treatment effects. The results of our simulations say that, in determining optimal treatment timing, the model with state-dependent impulsive control is more efficient than that with fixed-time impulsive control.

  18. Conditional mouse models demonstrate oncogene-dependent differences in tumor maintenance and recurrence

    International Nuclear Information System (INIS)

    Tilli, Maddalena T; Furth, Priscilla A

    2003-01-01

    Diversity in the pathophysiology of breast cancer frustrates therapeutic progress. We need to understand how mechanisms activated by specific combinations of oncogenes, tumor suppressors, and hormonal signaling pathways govern response to therapy and prognosis. A recent series of investigations conducted by Chodosh and colleagues offers new insights into the similarities and differences between specific oncogenic pathways. Expression of three oncogenes relevant to pathways activated in human breast cancers (c-myc, activated neu and Wnt1) were targeted to murine mammary epithelial cells using the same transgenic tetracycline-responsive conditional gene expression system. While the individual transgenic lines demonstrate similarly high rates of tumor penetrance, rates of oncogene-independent tumor maintenance and recurrence following initial regression are significantly different, and are modifiable by mutations in specific cooperating oncogenes or loss of tumor suppressor gene expression. The experiments make three notable contributions. First, they illustrate that rates of tumor regression and recurrence following initial regression are dependent upon the pathways activated by the initiating oncogene. The experiments also demonstrate that altered expression or mutation of specific cooperating oncogenes or tumor suppressor genes results in different rates of tumor regression and recurrence. Finally, they exemplify the power of conditional mouse models for elucidating how specific molecular mechanisms give rise to the complexity of human cancer

  19. A Western-type diet accelerates tumor progression in an autochthonous mouse model of prostate cancer.

    Science.gov (United States)

    Llaverias, Gemma; Danilo, Christiane; Wang, Yu; Witkiewicz, Agnes K; Daumer, Kristin; Lisanti, Michael P; Frank, Philippe G

    2010-12-01

    Epidemiological studies have provided evidence suggesting an important role for diet and obesity in the development of cancer. Specifically, lipid nutrients of the diet have been identified as important regulators of tumor development and progression. In the present study, we have examined the role of dietary fat and cholesterol in the initiation and progression of prostate cancer using the well-characterized TRAMP mouse model. Consumption of a Western-type diet--that is, enriched in both fat and cholesterol--accelerated prostate tumor incidence and tumor burden compared to mice fed a control chow diet. Furthermore, we also show that this diet increased the extent and the histological grade of prostate tumors. These findings were confirmed by the presence of increased levels of protein markers of advanced tumors in prostates obtained from animals fed a Western-type diet compared to those obtained from control animals. Increased lung metastases in animals fed a Western-type diet were also observed. In addition, we found that with a Western diet, animals bearing tumors presented with reduced plasma cholesterol levels compared with animals fed a control diet. Finally, we show that tumors obtained from animals fed a Western-type diet displayed increased expression of the high-density lipoprotein receptor SR-BI and increased angiogenesis. Taken together, our data suggest that dietary fat and cholesterol play an important role in the development of prostate cancer.

  20. Heterotypic mouse models of canine osteosarcoma recapitulate tumor heterogeneity and biological behavior

    Directory of Open Access Journals (Sweden)

    Milcah C. Scott

    2016-12-01

    Full Text Available Osteosarcoma (OS is a heterogeneous and rare disease with a disproportionate impact because it mainly affects children and adolescents. Lamentably, more than half of patients with OS succumb to metastatic disease. Clarification of the etiology of the disease, development of better strategies to manage progression, and methods to guide personalized treatments are among the unmet health needs for OS patients. Progress in managing the disease has been hindered by the extreme heterogeneity of OS; thus, better models that accurately recapitulate the natural heterogeneity of the disease are needed. For this study, we used cell lines derived from two spontaneous canine OS tumors with distinctly different biological behavior (OS-1 and OS-2 for heterotypic in vivo modeling that recapitulates the heterogeneous biology and behavior of this disease. Both cell lines demonstrated stability of the transcriptome when grown as orthotopic xenografts in athymic nude mice. Consistent with the behavior of the original tumors, OS-2 xenografts grew more rapidly at the primary site and had greater propensity to disseminate to lung and establish microscopic metastasis. Moreover, OS-2 promoted formation of a different tumor-associated stromal environment than OS-1 xenografts. OS-2-derived tumors comprised a larger percentage of the xenograft tumors than OS-1-derived tumors. In addition, a robust pro-inflammatory population dominated the stromal cell infiltrates in OS-2 xenografts, whereas a mesenchymal population with a gene signature reflecting myogenic signaling dominated those in the OS-1 xenografts. Our studies show that canine OS cell lines maintain intrinsic features of the tumors from which they were derived and recapitulate the heterogeneous biology and behavior of bone cancer in mouse models. This system provides a resource to understand essential interactions between tumor cells and the stromal environment that drive the progression and metastatic propensity of

  1. WE-E-17A-01: Characterization of An Imaging-Based Model of Tumor Angiogenesis

    International Nuclear Information System (INIS)

    Adhikarla, V; Jeraj, R

    2014-01-01

    Purpose: Understanding the transient dynamics of tumor oxygenation is important when evaluating tumor-vasculature response to anti-angiogenic therapies. An imaging-based tumor-vasculature model was used to elucidate factors that affect these dynamics. Methods: Tumor growth depends on its doubling time (Td). Hypoxia increases pro-angiogenic factor (VEGF) concentration which is modeled to reduce vessel perfusion, attributing to its effect of increasing vascular permeability. Perfused vessel recruitment depends on the existing perfused vasculature, VEGF concentration and maximum VEGF concentration (VEGFmax) for vessel dysfunction. A convolution-based algorithm couples the tumor to the normal tissue vessel density (VD-nt). The parameters are benchmarked to published pre-clinical data and a sensitivity study evaluating the changes in the peak and time to peak tumor oxygenation characterizes them. The model is used to simulate changes in hypoxia and proliferation PET imaging data obtained using [Cu- 61]Cu-ATSM and [F-18]FLT respectively. Results: Td and VD-nt were found to be the most influential on peak tumor pO2 while VEGFmax was marginally influential. A +20 % change in Td, VD-nt and VEGFmax resulted in +50%, +25% and +5% increase in peak pO2. In contrast, Td was the most influential on the time to peak oxygenation with VD-nt and VEGFmax playing marginal roles. A +20% change in Td, VD-nt and VEGFmax increased the time to peak pO2 by +50%, +5% and +0%. A −20% change in the above parameters resulted in comparable decreases in the peak and time to peak pO2. Model application to the PET data was able to demonstrate the voxel-specific changes in hypoxia of the imaged tumor. Conclusion: Tumor-specific doubling time and vessel density are important parameters to be considered when evaluating hypoxia transients. While the current model simulates the oxygen dynamics of an untreated tumor, incorporation of therapeutic effects can make the model a potent tool for analyzing

  2. Advantages of a dual-tracer model over reference tissue models for binding potential measurement in tumors

    Science.gov (United States)

    Tichauer, K M; Samkoe, K S; Klubben, W S; Hasan, T; Pogue, B W

    2012-01-01

    The quantification of tumor molecular expression in vivo could have a significant impact for informing and monitoring immerging targeted therapies in oncology. Molecular imaging of targeted tracers can be used to quantify receptor expression in the form of a binding potential (BP) if the arterial input curve or a surrogate of it is also measured. However, the assumptions of the most common approaches (reference tissue models) may not be valid for use in tumors. In this study, the validity of reference tissue models is investigated for use in tumors experimentally and in simulations. Three different tumor lines were grown subcutaneously in athymic mice and the mice were injected with a mixture of an epidermal growth factor receptor- (EGFR-) targeted fluorescent tracer and an untargeted fluorescent tracer. A one-compartment plasma input model demonstrated that the transport kinetics of both tracers were significantly different between tumors and all potential reference tissues, and using the reference tissue model resulted in a theoretical underestimation in BP of 50 ± 37%. On the other hand, the targeted and untargeted tracers demonstrated similar transport kinetics, allowing a dual-tracer approach to be employed to accurately estimate binding potential (with a theoretical error of 0.23 ± 9.07%). These findings highlight the potential for using a dual-tracer approach to quantify receptor expression in tumors with abnormal hemodynamics, possibly to inform the choice or progress of molecular cancer therapies. PMID:23022732

  3. A Multimodal Imaging Approach for Longitudinal Evaluation of Bladder Tumor Development in an Orthotopic Murine Model.

    Directory of Open Access Journals (Sweden)

    Chantal Scheepbouwer

    Full Text Available Bladder cancer is the fourth most common malignancy amongst men in Western industrialized countries with an initial response rate of 70% for the non-muscle invasive type, and improving therapy efficacy is highly needed. For this, an appropriate, reliable animal model is essential to gain insight into mechanisms of tumor growth for use in response monitoring of (new agents. Several animal models have been described in previous studies, but so far success has been hampered due to the absence of imaging methods to follow tumor growth non-invasively over time. Recent developments of multimodal imaging methods for use in animal research have substantially strengthened these options of in vivo visualization of tumor growth. In the present study, a multimodal imaging approach was addressed to investigate bladder tumor proliferation longitudinally. The complementary abilities of Bioluminescence, High Resolution Ultrasound and Photo-acoustic Imaging permit a better understanding of bladder tumor development. Hybrid imaging modalities allow the integration of individual strengths to enable sensitive and improved quantification and understanding of tumor biology, and ultimately, can aid in the discovery and development of new therapeutics.

  4. Fluctuations induced extinction and stochastic resonance effect in a model of tumor growth with periodic treatment

    International Nuclear Information System (INIS)

    Li Dongxi; Xu Wei; Guo, Yongfeng; Xu Yong

    2011-01-01

    We investigate a stochastic model of tumor growth derived from the catalytic Michaelis-Menten reaction with positional and environmental fluctuations under subthreshold periodic treatment. Firstly, the influences of environmental fluctuations on the treatable stage are analyzed numerically. Applying the standard theory of stochastic resonance derived from the two-state approach, we derive the signal-to-noise ratio (SNR) analytically, which is used to measure the stochastic resonance phenomenon. It is found that the weak environmental fluctuations could induce the extinction of tumor cells in the subthreshold periodic treatment. The positional stability is better in favor of the treatment of the tumor cells. Besides, the appropriate and feasible treatment intensity and the treatment cycle should be highlighted considered in the treatment of tumor cells.

  5. Immunological tumor destruction in a murine melanoma model by targeted LTalpha independent of secondary lymphoid tissue

    DEFF Research Database (Denmark)

    Schrama, D.; Voigt, H.; Eggert, A.O.

    2008-01-01

    BACKGROUND: We previously demonstrated that targeting lymphotoxin alpha (LTalpha) to the tumor evokes its immunological destruction in a syngeneic B16 melanoma model. Since treatment was associated with the induction of peritumoral tertiary lymphoid tissue, we speculated that the induced immune...... of specific T-cell responses even in the absence of secondary lymphoid organs. In addition, this effect is accompanied by the initiation of tertiary lymphoid tissue at the tumor site in which B and T lymphocytes are compartmentalized in defined areas and which harbor expanded numbers of tumor specific T cells...... as demonstrated by in situ TRP-2/K(b) tetramer staining. Mechanistically, targeted LTalpha therapy seems to induce changes at the tumor site which allows a coordinated interaction of immune competent cells triggering the induction of tertiary lymphoid tissue. CONCLUSION: Thus, our data demonstrate that targeted...

  6. Fluid absorption related to ion transport in human airway epithelial spheroids

    DEFF Research Database (Denmark)

    Pedersen, P S; Holstein-Rathlou, N H; Larsen, P L

    1999-01-01

    , and amiloride inhibited both values. Fluid transport rates were calculated from repeated measurements of spheroid diameters. The results showed that 1) non-CF and CF spheroids absorbed fluid at identical rates (4.4 microl x cm(-2) x h(-1)), 2) amiloride inhibited fluid absorption to a lower residual level...... in non-CF than in CF spheroids, 3) Cl(-)-channel inhibitors increased fluid absorption in amiloride-treated non-CF spheroids to a level equal to that of amiloride-treated CF spheroids, 4) hydrochlorothiazide reduced the amiloride-insensitive fluid absorption in both non-CF and CF spheroids, and 5......) osmotic water permeabilities were equal in non-CF and CF spheroids ( approximately 27 x 10(-7) cm x s(-1) x atm(-1))....

  7. Induction of Anti-Tumor Immune Responses by Peptide Receptor Radionuclide Therapy with 177Lu-DOTATATE in a Murine Model of a Human Neuroendocrine Tumor

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    Michael Bzorek

    2013-10-01

    Full Text Available Peptide receptor radionuclide therapy (PRRT is a relatively new mode of internally targeted radiotherapy currently in clinical trials. In PRRT, ionizing radioisotopes conjugated to somatostatin analogues are targeted to neuroendocrine tumors (NETs via somatostatin receptors. Despite promising clinical results, very little is known about the mechanism of tumor control. By using NCI-H727 cells in an in vivo murine xenograft model of human NETs, we showed that 177Lu-DOTATATE PRRT led to increased infiltration of CD86+ antigen presenting cells into tumor tissue. We also found that following treatment with PRRT, there was significantly increased tumor infiltration by CD49b+/FasL+ NK cells potentially capable of tumor killing. Further investigation into the immunomodulatory effects of PRRT will be essential in improving treatment efficacy.

  8. Combination therapy targeting the tumor microenvironment is effective in a model of human ocular melanoma

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    Schafer Peter H

    2007-07-01

    Full Text Available Abstract Background Ocular melanoma is the leading intraocular malignancy. There is no effective treatment for metastatic ocular melanoma. We sought a treatment targeting the tumor microenvironment as well as the tumor cells. Methods Migration of HUVEC cells, the ability of HUVEC cells to form tubes, and proliferative capacity of a human ocular melanoma cell line were tested in the presence of lenalidomide and sorafenib alone and in combination. The compounds were also tested in a rat aortic ring assay and were tested in a highly aggressive human ocular melanoma xenograft model. Results Lenalidomide and Sorafenib inhibit HUVEC ability to migrate and form tubes and when used in combination the inhibition is increased. The agents alone and in combination inhibit outgrowth in the rat aortic ring model. The combination of the agents improved the inhibition over either single agent. In a xenograft model, combination therapy inhibited tumor growth over inhibition by single agent alone in a significant fashion (p Conclusion Lenalidomide and sorafenib are effective at targeting endothelial cells, inhibiting growth of ocular melanoma cells and can inhibit growth of tumors in a xenograft model as well as inhibit development of metastases. Combining these agents works in an additive to synergistic way to inhibit the growth of tumors and development of metastases.

  9. Mathematical modeling of interleukin-27 induction of anti-tumor T cells response.

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    Kang-Ling Liao

    Full Text Available Interleukin-12 is a pro-inflammatory cytokine which promotes Th1 and cytotoxic T lymphocyte activities, such as Interferon-[Formula: see text] secretion. For this reason Interleukin-12 could be a powerful therapeutic agent for cancer treatment. However, Interleukin-12 is also excessively toxic. Interleukin-27 is an immunoregulatory cytokine from the Interleukin-12 family, but it is not as toxic as Interleukin-12. In recent years, Interleukin-27 has been considered as a potential anti-tumor agent. Recent experiments in vitro and in vivo have shown that cancer cells transfected with IL-27 activate CD8+ T cells to promote the secretion of anti-tumor cytokines Interleukin-10, although, at the same time, IL-27 inhibits the secretion of Interferon-[Formula: see text] by CD8+ T cells. In the present paper we develop a mathematical model based on these experimental results. The model involves a dynamic network which includes tumor cells, CD8+ T cells and cytokines Interleukin-27, Interleukin-10 and Interferon-[Formula: see text]. Simulations of the model show how Interleukin-27 promotes CD8+ T cells to secrete Interleukin-10 to inhibit tumor growth. On the other hand Interleukin-27 inhibits the secretion of Interferon-[Formula: see text] by CD8+ T cells which somewhat diminishes the inhibition of tumor growth. Our numerical results are in qualitative agreement with experimental data. We use the model to design protocols of IL-27 injections for the treatment of cancer and find that, for some special types of cancer, with a fixed total amount of drug, within a certain range, continuous injection has better efficacy than intermittent injections in reducing the tumor load while the treatment is ongoing, although the decrease in tumor load is only temporary.

  10. Image-based modeling of tumor shrinkage in head and neck radiation therapy

    International Nuclear Information System (INIS)

    Chao Ming; Xie Yaoqin; Moros, Eduardo G.; Le, Quynh-Thu; Xing Lei

    2010-01-01

    Purpose: Understanding the kinetics of tumor growth/shrinkage represents a critical step in quantitative assessment of therapeutics and realization of adaptive radiation therapy. This article presents a novel framework for image-based modeling of tumor change and demonstrates its performance with synthetic images and clinical cases. Methods: Due to significant tumor tissue content changes, similarity-based models are not suitable for describing the process of tumor volume changes. Under the hypothesis that tissue features in a tumor volume or at the boundary region are partially preserved, the kinetic change was modeled in two steps: (1) Autodetection of homologous tissue features shared by two input images using the scale invariance feature transformation (SIFT) method; and (2) establishment of a voxel-to-voxel correspondence between the images for the remaining spatial points by interpolation. The correctness of the tissue feature correspondence was assured by a bidirectional association procedure, where SIFT features were mapped from template to target images and reversely. A series of digital phantom experiments and five head and neck clinical cases were used to assess the performance of the proposed technique. Results: The proposed technique can faithfully identify the known changes introduced when constructing the digital phantoms. The subsequent feature-guided thin plate spline calculation reproduced the ''ground truth'' with accuracy better than 1.5 mm. For the clinical cases, the new algorithm worked reliably for a volume change as large as 30%. Conclusions: An image-based tumor kinetic algorithm was developed to model the tumor response to radiation therapy. The technique provides a practical framework for future application in adaptive radiation therapy.

  11. Combined thermal and elastic modeling of the normal and tumorous breast

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    Jiang, Li; Zhan, Wang; Loew, Murray

    2008-03-01

    The abnormal thermogram has been shown to be a reliable indicator of a high risk of breast cancer, but an open question is how to quantify the complex relationships between the breast thermal behaviors and the underlying physiological/pathological conditions. Previous thermal modeling techniques generally did not utilize the breast geometry determined by the gravity-induced elastic deformations arising from various body postures. In this paper, a 3-D finite-element method is developed for combined modeling of the thermal and elastic properties of the breast, including the mechanical nonlinearity associated with large deformations. The effects of the thermal and elastic properties of the breast tissues are investigated quantitatively. For the normal breast in a standing/sitting up posture, the gravity-induced deformation alone is found to be able to cause an asymmetric temperature distribution even though all the thermal/elastic properties are symmetrical, and this temperature asymmetry increases for softer and more compressible breast tissues. For a tumorous breast, we found that the surface-temperature alterations generally can be recognizable for superficial tumors at depths less than 20 mm. Tumor size plays a less important role than the tumor depth in determining the tumor-induced temperature difference. This result may imply that a higher thermal sensitivity is critical for a breast thermogram system when deeper tumors are present, even if the tumor is relatively large. We expect this new method to provide a stronger foundation for, and greater specificity and precision in, thermographic diagnosis and treatment of breast tumors.

  12. MicroRNA signature characterizes primary tumors that metastasize in an esophageal adenocarcinoma rat model.

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    Ali H Zaidi

    Full Text Available To establish a miRNA signature for metastasis in an animal model of esophageal adenocarcinoma (EAC.The incidence of esophageal adenocarcinoma (EAC has dramatically increased and esophageal cancer is now the sixth leading cause of cancer deaths worldwide. Mortality rates remain high among patients with advanced stage disease and esophagectomy is associated with high complication rates. Hence, early identification of potentially metastatic disease would better guide treatment strategies.The modified Levrat's surgery was performed to induce EAC in Sprague-Dawley rats. Primary EAC and distant metastatic sites were confirmed via histology and immunofluorescence. miRNA profiling was performed on primary tumors with or without metastasis. A unique subset of miRNAs expressed in primary tumors and metastases was identified with Ingenuity Pathway Analysis (IPA along with upstream and downstream targets. miRNA-linked gene expression analysis was performed on a secondary cohort of metastasis positive (n=5 and metastasis negative (n=28 primary tumors.The epithelial origin of distant metastasis was established by IF using villin (VIL1 and mucin 5AC (MUC5AC antibodies. miRNome analysis identified four down-regulated miRNAs in metastasis positive primary tumors compared to metastasis negative tumors: miR-92a-3p (p=0.0001, miR-141-3p (p=0.0022, miR-451-1a (p=0.0181 and miR133a-3p (p=0.0304. Six target genes identified in the top scoring networks by IPA were validated as significantly, differentially expressed in metastasis positive primary tumors: Ago2, Akt1, Kras, Bcl2L11, CDKN1B and Zeb2.In vivo metastasis was confirmed in the modified Levrat's model. Analysis of the primary tumor identified a distinctive miRNA signature for primary tumors that metastasized.

  13. Mesenchymal stem cell 1 (MSC1-based therapy attenuates tumor growth whereas MSC2-treatment promotes tumor growth and metastasis.

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    Ruth S Waterman

    Full Text Available Currently, there are many promising clinical trials using mesenchymal stem cells (MSCs in cell-based therapies of numerous diseases. Increasingly, however, there is a concern over the use of MSCs because they home to tumors and can support tumor growth and metastasis. For instance, we established that MSCs in the ovarian tumor microenvironment promoted tumor growth and favored angiogenesis. In parallel studies, we also developed a new approach to induce the conventional mixed pool of MSCs into two uniform but distinct phenotypes we termed MSC1 and MSC2.Here we tested the in vitro and in vivo stability of MSC1 and MSC2 phenotypes as well as their effects on tumor growth and spread. In vitro co-culture of MSC1 with various cancer cells diminished growth in colony forming units and tumor spheroid assays, while conventional MSCs or MSC2 co-culture had the opposite effect in these assays. Co-culture of MSC1 and cancer cells also distinctly affected their migration and invasion potential when compared to MSCs or MSC2 treated samples. The expression of bioactive molecules also differed dramatically among these samples. MSC1-based treatment of established tumors in an immune competent model attenuated tumor growth and metastasis in contrast to MSCs- and MSC2-treated animals in which tumor growth and spread was increased. Also, in contrast to these groups, MSC1-therapy led to less ascites accumulation, increased CD45+leukocytes, decreased collagen deposition, and mast cell degranulation.These observations indicate that the MSC1 and MSC2 phenotypes may be convenient tools for the discovery of critical components of the tumor stroma. The continued investigation of these cells may help ensure that cell based-therapy is used safely and effectively in human disease.

  14. Oxygen distribution in tumors: A qualitative analysis and modeling study providing a novel Monte Carlo approach

    International Nuclear Information System (INIS)

    Lagerlöf, Jakob H.; Kindblom, Jon; Bernhardt, Peter

    2014-01-01

    Purpose: To construct a Monte Carlo (MC)-based simulation model for analyzing the dependence of tumor oxygen distribution on different variables related to tumor vasculature [blood velocity, vessel-to-vessel proximity (vessel proximity), and inflowing oxygen partial pressure (pO 2 )]. Methods: A voxel-based tissue model containing parallel capillaries with square cross-sections (sides of 10 μm) was constructed. Green's function was used for diffusion calculations and Michaelis-Menten's kinetics to manage oxygen consumption. The model was tuned to approximately reproduce the oxygenational status of a renal carcinoma; the depth oxygenation curves (DOC) were fitted with an analytical expression to facilitate rapid MC simulations of tumor oxygen distribution. DOCs were simulated with three variables at three settings each (blood velocity, vessel proximity, and inflowing pO 2 ), which resulted in 27 combinations of conditions. To create a model that simulated variable oxygen distributions, the oxygen tension at a specific point was randomly sampled with trilinear interpolation in the dataset from the first simulation. Six correlations between blood velocity, vessel proximity, and inflowing pO 2 were hypothesized. Variable models with correlated parameters were compared to each other and to a nonvariable, DOC-based model to evaluate the differences in simulated oxygen distributions and tumor radiosensitivities for different tumor sizes. Results: For tumors with radii ranging from 5 to 30 mm, the nonvariable DOC model tended to generate normal or log-normal oxygen distributions, with a cut-off at zero. The pO 2 distributions simulated with the six-variable DOC models were quite different from the distributions generated with the nonvariable DOC model; in the former case the variable models simulated oxygen distributions that were more similar to in vivo results found in the literature. For larger tumors, the oxygen distributions became truncated in the lower

  15. 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.

  16. Germline genetic variation modulates tumor progression and metastasis in a mouse model of neuroendocrine prostate carcinoma.

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    Shashank J Patel

    Full Text Available Neuroendocrine (NE differentiation has gained increased attention as a prostate cancer (PC prognostic marker. The aim of this study is to determine whether host germline genetic variation influences tumor progression and metastasis in C57BL/6-Tg(TRAMP8247Ng/J (TRAMP mouse model of aggressive NEPC. TRAMP mice were crossed to the eight progenitor strains of the Collaborative Cross recombinant inbred panel to address this. Tumor growth and metastasis burden were quantified in heterozygous transgene positive F1 male mice at 30 weeks of age. Compared to wild-type C57BL/6J-Tg(TRAMP824Ng/J males, TRAMP x CAST/EiJ, TRAMP x NOD/ShiLtJ and TRAMP x NZO/HlLtJ F1 males displayed significant increases in tumor growth. Conversely, TRAMP x WSB/EiJ and TRAMP x PWK/PhJ F1 males displayed significant reductions in tumor growth. Interestingly, despite reduced tumor burden, TRAMP x WSB/EiJ males had an increased nodal metastasis burden. Patterns of distant pulmonary metastasis tended to follow the same patterns as that of local dissemination in each of the strains. All tumors and metastases displayed positive staining for NE markers, synaptophysin, and FOXA2. These experiments conclusively demonstrate that the introduction of germline variation by breeding modulates tumor growth, local metastasis burden, and distant metastasis frequency in this model of NEPC. These strains will be useful as model systems to facilitate the identification of germline modifier genes that promote the development of aggressive forms of PC.

  17. Three-dimensional in vitro tumor models for cancer research and drug evaluation.

    Science.gov (United States)

    Xu, Xian; Farach-Carson, Mary C; Jia, Xinqiao

    2014-11-15

    Cancer occurs when cells acquire genomic instability and inflammation, produce abnormal levels of epigenetic factors/proteins and tumor suppressors, reprogram the energy metabolism and evade immune destruction, leading to the disruption of cell cycle/normal growth. An early event in carcinogenesis is loss of polarity and detachment from the natural basement membrane, allowing cells to form distinct three-dimensional (3D) structures that interact with each other and with the surrounding microenvironment. Although valuable information has been accumulated from traditional in vitro studies in which cells are grown on flat and hard plastic surfaces (2D culture), this culture condition does not reflect the essential features of tumor tissues. Further, fundamental understanding of cancer metastasis cannot be obtained readily from 2D studies because they lack the complex and dynamic cell-cell communications and cell-matrix interactions that occur during cancer metastasis. These shortcomings, along with lack of spatial depth and cell connectivity, limit the applicability of 2D cultures to accurate testing of pharmacologically active compounds, free or sequestered in nanoparticles. To recapitulate features of native tumor microenvironments, various biomimetic 3D tumor models have been developed to incorporate cancer and stromal cells, relevant matrix components, and biochemical and biophysical cues, into one spatially and temporally integrated system. In this article, we review recent advances in creating 3D tumor models employing tissue engineering principles. We then evaluate the utilities of these novel models for the testing of anticancer drugs and their delivery systems. We highlight the profound differences in responses from 3D in vitro tumors and conventional monolayer cultures. Overall, strategic integration of biological principles and engineering approaches will both improve understanding of tumor progression and invasion and support discovery of more personalized

  18. Stereoscopic virtual reality models for planning tumor resection in the sellar region

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    Wang Shou-sen

    2012-11-01

    Full Text Available Abstract Background It is difficult for neurosurgeons to perceive the complex three-dimensional anatomical relationships in the sellar region. Methods To investigate the value of using a virtual reality system for planning resection of sellar region tumors. The study included 60 patients with sellar tumors. All patients underwent computed tomography angiography, MRI-T1W1, and contrast enhanced MRI-T1W1 image sequence scanning. The CT and MRI scanning data were collected and then imported into a Dextroscope imaging workstation, a virtual reality system that allows structures to be viewed stereoscopically. During preoperative assessment, typical images for each patient were chosen and printed out for use by the surgeons as references during surgery. Results All sellar tumor models clearly displayed bone, the internal carotid artery, circle of Willis and its branches, the optic nerve and chiasm, ventricular system, tumor, brain, soft tissue and adjacent structures. Depending on the location of the tumors, we simulated the transmononasal sphenoid sinus approach, transpterional approach, and other approaches. Eleven surgeons who used virtual reality models completed a survey questionnaire. Nine of the participants said that the virtual reality images were superior to other images but that other images needed to be used in combination with the virtual reality images. Conclusions The three-dimensional virtual reality models were helpful for individualized planning of surgery in the sellar region. Virtual reality appears to be promising as a valuable tool for sellar region surgery in the future.

  19. Characterization of a switchable chimeric antigen receptor platform in a pre-clinical solid tumor model.

    Science.gov (United States)

    Pishali Bejestani, Elham; Cartellieri, Marc; Bergmann, Ralf; Ehninger, Armin; Loff, Simon; Kramer, Michael; Spehr, Johannes; Dietrich, Antje; Feldmann, Anja; Albert, Susann; Wermke, Martin; Baumann, Michael; Krause, Mechthild; Bornhäuser, Martin; Ehninger, Gerhard; Bachmann, Michael; von Bonin, Malte

    2017-01-01

    The universal modular chimeric antigen receptor (UniCAR) platform redirects CAR-T cells using a separated, soluble targeting module with a short half-life. This segregation allows precise controllability and flexibility. Herein we show that the UniCAR platform can be used to efficiently target solid cancers in vitro and in vivo using a pre-clinical prostate cancer model which overexpresses prostate stem cell antigen (PSCA). Short-term administration of the targeting module to tumor bearing immunocompromised mice engrafted with human UniCAR-T cells significantly delayed tumor growth and prolonged survival of recipient mice both in a low and high tumor burden model. In addition, we analyzed phenotypic and functional changes of cancer cells and UniCAR-T cells in association with the administration of the targeting module to reveal potential immunoevasive mechanisms. Most notably, UniCAR-T cell activation induced upregulation of immune-inhibitory molecules such as programmed death ligands. In conclusion, this work illustrates that the UniCAR platform mediates potent anti-tumor activity in a relevant in vitro and in vivo solid tumor model.

  20. Tumor-Derived Cell Lines as Molecular Models of Cancer Pharmacogenomics.

    Science.gov (United States)

    Goodspeed, Andrew; Heiser, Laura M; Gray, Joe W; Costello, James C

    2016-01-01

    Compared with normal cells, tumor cells have undergone an array of genetic and epigenetic alterations. Often, these changes underlie cancer development, progression, and drug resistance, so the utility of model systems rests on their ability to recapitulate the genomic aberrations observed in primary tumors. Tumor-derived cell lines have long been used to study the underlying biologic processes in cancer, as well as screening platforms for discovering and evaluating the efficacy of anticancer therapeutics. Multiple -omic measurements across more than a thousand cancer cell lines have been produced following advances in high-throughput technologies and multigroup collaborative projects. These data complement the large, international cancer genomic sequencing efforts to characterize patient tumors, such as The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC). Given the scope and scale of data that have been generated, researchers are now in a position to evaluate the similarities and differences that exist in genomic features between cell lines and patient samples. As pharmacogenomics models, cell lines offer the advantages of being easily grown, relatively inexpensive, and amenable to high-throughput testing of therapeutic agents. Data generated from cell lines can then be used to link cellular drug response to genomic features, where the ultimate goal is to build predictive signatures of patient outcome. This review highlights the recent work that has compared -omic profiles of cell lines with primary tumors, and discusses the advantages and disadvantages of cancer cell lines as pharmacogenomic models of anticancer therapies. ©2015 American Association for Cancer Research.

  1. Nuclear star clusters and the stellar spheroids of their host galaxies

    Science.gov (United States)

    Leigh, Nathan; Böker, Torsten; Knigge, Christian

    2012-08-01

    We combine published photometry for the nuclear star clusters (NSCs) and stellar spheroids of 51 low-mass, early-type galaxies in the Virgo cluster with empirical mass-to-light ratios, in order to complement previous studies that explore the dependence of NSC masses on various properties of their host galaxies. We confirm a roughly linear relationship between NSC mass and luminous host spheroid mass, albeit with considerable scatter (0.57 dex). In order to translate this into an MNSC-σ relation, we estimate velocity dispersions from the virial theorem, assuming that all galaxies in our sample share a common dark matter fraction and are dynamically relaxed. We then find that MNSC ˜ σ2.73 ± 0.29, with a slightly reduced scatter of 0.54 dex. This confirms recent results that the shape of the MCMO-σ relation is different for NSCs and super-massive black holes. We discuss this result in the context of the generalized idea of 'central massive objects' (CMOs). In order to assess which physical parameters drive the observed nuclear cluster masses, we also carry out a joint multivariate power-law fit to the data. In this, we allow the nuclear cluster mass to depend on spheroid mass and radius (and hence implicitly on velocity dispersion), as well as on the size of the globular cluster reservoir. When considered together, the dependences on MSph and RSph are roughly consistent with the virial theorem, and therefore MNSC ∝ σ2. However, the only statistically significant correlation appears to be a simple linear scaling between NSC mass and luminous spheroid mass. We proceed to directly compare the derived NSC masses with predictions for two popular models for NSC formation, namely (i) globular cluster infall due to dynamical friction and (ii) in situ formation during the early phases of galaxy formation that is regulated via momentum feedback from stellar winds and/or supernovae. Neither model can directly predict the observations, and we discuss possible

  2. Kinetic modeling of tumor growth and dissemination in the craniospinal axis: implications for craniospinal irradiation

    Directory of Open Access Journals (Sweden)

    Halperin Edward C

    2006-12-01

    Full Text Available Abstract Background Medulloblastoma and other types of tumors that gain access to the cerebrospinal fluid can spread throughout the craniospinal axis. The purpose of this study was to devise a simple multi-compartment kinetic model using established tumor cell growth and treatment sensitivity parameters to model the complications of this spread as well as the impact of treatment with craniospinal radiotherapy. Methods A two-compartment mathematical model was constructed. Rate constants were derived from previously published work and the model used to predict outcomes for various clinical scenarios. Results The model is simple and with the use of known and estimated clinical parameters is consistent with known clinical outcomes. Treatment outcomes are critically dependent upon the duration of the treatment break and the radiosensitivity of the tumor. Cross-plot analyses serve as an estimate of likelihood of cure as a function of these and other factors. Conclusion The model accurately describes known clinical outcomes for patients with medulloblastoma. It can help guide treatment decisions for radiation oncologists treating patients with this disease. Incorporation of other treatment modalities, such as chemotherapy, that enhance radiation sensitivity and/or reduce tumor burden, are predicted to significantly increase the probability of cure.

  3. A preoperative mathematic model for computed tomographic guided microwave ablation treatment of hepatic dome tumors.

    Science.gov (United States)

    Gao, Fei; Wang, Guo-Bao; Xiang, Zhan-Wang; Yang, Bin; Xue, Jing-Bing; Mo, Zhi-Qiang; Zhong, Zhi-Hui; Zhang, Tao; Zhang, Fu-Jun; Fan, Wei-Jun

    2016-05-03

    This study sought to prospectively evaluate the feasibility and safety of a preoperative mathematic model for computed tomographic(CT) guided microwave(MW) ablation treatment of hepatic dome tumors. This mathematic model was a regular cylinder quantifying appropriate puncture routes from the bottom up. A total of 103 patients with hepatic dome tumors were enrolled and randomly divided into 2 groups based on whether this model was used or not: Group A (using the model; n = 43) versus Group B (not using the model; n = 60). All tumors were treated by CT-guided MW ablation and follow-up contrast CT were reviewed. The average number of times for successful puncture, average ablation time, and incidence of right shoulder pain were less in Group A than Group B (1.4 vs. 2.5, P = 0.001; 8.8 vs. 11.1 minutes, P = 0.003; and 4.7% vs. 20%, P = 0.039). The technical success rate was higher in Group A than Group B (97.7% vs. 85.0%, P = 0.032). There were no significant differences between the two groups in primary and secondary technique efficacy rates (97.7% vs. 88.3%, P = 0.081; 90.0% vs. 72.7%, P = 0.314). No major complications occurred in both groups. The mathematic model of regular cylinder is feasible and safe for CT-guided MW ablation in treating hepatic dome tumors.

  4. Innovative Disease Model: Zebrafish as an In Vivo Platform for Intestinal Disorder and Tumors

    Directory of Open Access Journals (Sweden)

    Jeng-Wei Lu

    2017-09-01

    Full Text Available Colorectal cancer (CRC is one of the world’s most common cancers and is the second leading cause of cancer deaths, causing more than 50,000 estimated deaths each year. Several risk factors are highly associated with CRC, including being overweight, eating a diet high in red meat and over-processed meat, having a history of inflammatory bowel disease, and smoking. Previous zebrafish studies have demonstrated that multiple oncogenes and tumor suppressor genes can be regulated through genetic or epigenetic alterations. Zebrafish research has also revealed that the activation of carcinogenesis-associated signal pathways plays an important role in CRC. The biology of cancer, intestinal disorders caused by carcinogens, and the morphological patterns of tumors have been found to be highly similar between zebrafish and humans. Therefore, the zebrafish has become an important animal model for translational medical research. Several zebrafish models have been developed to elucidate the characteristics of gastrointestinal diseases. This review article focuses on zebrafish models that have been used to study human intestinal disorders and tumors, including models involving mutant and transgenic fish. We also report on xenograft models and chemically-induced enterocolitis. This review demonstrates that excellent zebrafish models can provide novel insights into the pathogenesis of gastrointestinal diseases and help facilitate the evaluation of novel anti-tumor drugs.

  5. Biomimicry 3D gastrointestinal spheroid platform for the assessment of toxicity and inflammatory effects of zinc oxide nanoparticles.

    Science.gov (United States)

    Chia, Sing Ling; Tay, Chor Yong; Setyawati, Magdiel I; Leong, David T

    2015-02-11

    Our current mechanistic understanding on the effects of engineered nanoparticles (NPs) on cellular physiology is derived mainly from 2D cell culture studies. However, conventional monolayer cell culture may not accurately model the mass transfer gradient that is expected in 3D tissue physiology and thus may lead to artifactual experimental conclusions. Herein, using a micropatterned agarose hydrogel platform, the effects of ZnO NPs (25 nm) on 3D colon cell spheroids of well-defined sizes are examined. The findings show that cell dimensionality plays a critical role in governing the spatiotemporal cellular outcomes like inflammatory response and cytotoxicity in response to ZnO NPs treatment. More importantly, ZnO NPs can induce different modes of cell death in 2D and 3D cell culture systems. Interestingly, the outer few layers of cells in 3D model could only protect the inner core of cells for a limited time and periodically slough off from the spheroids surface. These findings suggest that toxicological conclusions made from 2D cell models might overestimate the toxicity of ZnO NPs. This 3D cell spheroid model can serve as a reproducible platform to better reflect the actual cell response to NPs and to study a more realistic mechanism of nanoparticle-induced toxicity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Accessing 3D microtissue metabolism: Lactate and oxygen monitoring in hepatocyte spheroids.

    Science.gov (United States)

    Weltin, Andreas; Hammer, Steffen; Noor, Fozia; Kaminski, Yeda; Kieninger, Jochen; Urban, Gerald A

    2017-01-15

    3D hepatic microtissues, unlike 2D cell cultures, retain many of the in-vivo-like functionalities even after long-term cultivation. Such 3D cultures are increasingly applied to investigate liver damage due to drug exposure in toxicology. However, there is a need for thorough metabolic characterization of these microtissues for mechanistic understanding of effects on culture behaviour. We measured metabolic parameters from single human HepaRG hepatocyte spheroids online and continuously with electrochemical microsensors. A microsensor platform for lactate and oxygen was integrated in a standard 96-well plate. Electrochemical microsensors for lactate and oxygen allow fast, precise and continuous long-term measurement of metabolic parameters directly in the microwell. The demonstrated capability to precisely detect small concentration changes by single spheroids is the key to access their metabolism. Lactate levels in the culture medium starting from 50µM with production rates of 5µMh -1 were monitored and precisely quantified over three days. Parallel long-term oxygen measurements showed no oxygen depletion or hypoxic conditions in the microwell. Increased lactate production by spheroids upon suppression of the aerobic metabolism was observed. The dose-dependent decrease in lactate production caused by the addition of the hepatotoxic drug Bosentan was determined. We showed that in a toxicological application, metabolic monitoring yields quantitative, online information on cell viability, which complements and supports other methods such as microscopy. The demonstrated continuous access to 3D cell culture metabolism within a standard setup improves in vitro toxicology models in replacement strategies of animal experiments. Controlling the microenvironment of such organotypic cultures has impact in tissue engineering, cancer therapy and personalized medicine. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Short hairpin RNA targeting of fibroblast activation protein inhibits tumor growth and improves the tumor microenvironment in a mouse model

    Directory of Open Access Journals (Sweden)

    Fan Cai

    2013-05-01

    Full Text Available Fibroblast activation protein (FAP is a specific serine proteaseexpressed in tumor stroma proven to be a stimulatory factor inthe progression of some cancers. The purpose of this studywas to investigate the effects of FAP knockdown on tumorgrowth and the tumor microenvironment. Mice bearing 4T1subcutaneous tumors were treated with liposome-shRNAcomplexes targeting FAP. Tumor volumes and weights weremonitored, and FAP, collagen, microvessel density (MVD,and apoptosis were measured. Our studies showed thatshRNA targeting of FAP in murine breast cancer reduces FAPexpression, inhibits tumor growth, promotes collagenaccumulation (38%, and suppresses angiogenesis (71.7%, aswell as promoting apoptosis (by threefold. We suggest thatFAP plays a role in tumor growth and in altering the tumormicroenvironment. Targeting FAP may therefore represent asupplementary therapy for breast cancer. [BMB Reports 2013;46(5: 252-257

  8. Bigh3 silencing increases retinoblastoma tumor growth in the murine SV40-TAg-Rb model.

    Science.gov (United States)

    Allaman-Pillet, Nathalie; Oberson, Anne; Schorderet, Daniel F

    2017-02-28

    BIGH3, a secreted protein of the extracellular matrix interacts with collagen and integrins on the cell surface. BIGH3 can have opposing functions in cancer, acting either as tumor suppressor or promoter by enhancing tumor progression and angiogenesis. In the eye, BIGH3 is expressed in the cornea and the retinal pigment epithelium and could impact on the development of retinoblastoma, the most common paediatric intraocular neoplasm. Retinoblastoma initiation requires the inactivation of both alleles of the RB1 tumor suppressor gene in the developing retina and tumor progression involves additional genomic changes. To determine whether BIGH3 affects retinoblastoma development, we generated a retinoblastoma mouse model with disruption of the Bigh3 genomic locus. Bigh3 silencing in these mice resulted in enhanced tumor development in the retina. A decrease in apoptosis is involved in the initial events of tumorigenesis, followed by an increased activity of the pro-survival ERK pathway as well as an upregulation of cyclin-dependent kinases (CDKs). Taken together, these data suggest that BIGH3 acts as a tumor suppressor in the retina.

  9. Radio-photothermal therapy mediated by a single compartment nanoplatform depletes tumor initiating cells and reduces lung metastasis in the orthotopic 4T1 breast tumor model

    Science.gov (United States)

    Zhou, Min; Zhao, Jun; Tian, Mei; Song, Shaoli; Zhang, Rui; Gupta, Sanjay; Tan, Dongfeng; Shen, Haifa; Ferrari, Mauro; Li, Chun

    2015-11-01

    Tumor Initiating Cells (TICs) are resistant to radiotherapy and chemotherapy, and are believed to be responsible for tumor recurrence and metastasis. Combination therapies can overcome the limitation of conventional cancer treatments, and have demonstrated promising application in the clinic. Here, we show that dual modality radiotherapy (RT) and photothermal therapy (PTT) mediated by a single compartment nanosystem copper-64-labeled copper sulfide nanoparticles ([64Cu]CuS NPs) could suppress breast tumor metastasis through eradication of TICs. Positron electron tomography (PET) imaging and biodistribution studies showed that more than 90% of [64Cu]CuS NPs was retained in subcutaneously grown BT474 breast tumor 24 h after intratumoral (i.t.) injection, indicating the NPs are suitable for the combination therapy. Combined RT/PTT therapy resulted in significant tumor growth delay in the subcutaneous BT474 breast cancer model. Moreover, RT/PTT treatment significantly prolonged the survival of mice bearing orthotopic 4T1 breast tumors compared to no treatment, RT alone, or PTT alone. The RT/PTT combination therapy significantly reduced the number of tumor nodules in the lung and the formation of tumor mammospheres from treated 4T1 tumors. No obvious side effects of the CuS NPs were noted in the treated mice in a pilot toxicity study. Taken together, our data support the feasibility of a therapeutic approach for the suppression of tumor metastasis through localized RT/PTT therapy.Tumor Initiating Cells (TICs) are resistant to radiotherapy and chemotherapy, and are believed to be responsible for tumor recurrence and metastasis. Combination therapies can overcome the limitation of conventional cancer treatments, and have demonstrated promising application in the clinic. Here, we show that dual modality radiotherapy (RT) and photothermal therapy (PTT) mediated by a single compartment nanosystem copper-64-labeled copper sulfide nanoparticles ([64Cu]CuS NPs) could suppress

  10. Comparison between model-predicted tumor oxygenation dynamics and vascular-/flow-related Doppler indices.

    Science.gov (United States)

    Belfatto, Antonella; Vidal Urbinati, Ailyn M; Ciardo, Delia; Franchi, Dorella; Cattani, Federica; Lazzari, Roberta; Jereczek-Fossa, Barbara A; Orecchia, Roberto; Baroni, Guido; Cerveri, Pietro

    2017-05-01

    Mathematical modeling is a powerful and flexible method to investigate complex phenomena. It discloses the possibility of reproducing expensive as well as invasive experiments in a safe environment with limited costs. This makes it suitable to mimic tumor evolution and response to radiotherapy although the reliability of the results remains an issue. Complexity reduction is therefore a critical aspect in order to be able to compare model outcomes to clinical data. Among the factors affecting treatment efficacy, tumor oxygenation is known to play a key role in radiotherapy response. In this work, we aim at relating the oxygenation dynamics, predicted by a macroscale model trained on tumor volumetric data of uterine cervical cancer patients, to vascularization and blood flux indices assessed on Ultrasound Doppler images. We propose a macroscale model of tumor evolution based on three dynamics, namely active portion, necrotic portion, and oxygenation. The model parameters were assessed on the volume size of seven cervical cancer patients administered with 28 fractions of intensity modulated radiation therapy (IMRT) (1.8 Gy/fraction). For each patient, five Doppler ultrasound tests were acquired before, during, and after the treatment. The lesion was manually contoured by an expert physician using 4D View ® (General Electric Company - Fairfield, Connecticut, United States), which automatically provided the overall tumor volume size along with three vascularization and/or blood flow indices. Volume data only were fed to the model for training purpose, while the predicted oxygenation was compared a posteriori to the measured Doppler indices. The model was able to fit the tumor volume evolution within 8% error (range: 3-8%). A strong correlation between the intrapatient longitudinal indices from Doppler measurements and oxygen predicted by the model (about 90% or above) was found in three cases. Two patients showed an average correlation value (50-70%) and the remaining

  11. Sensitivity of MRI tumor biomarkers to VEGFR inhibitor therapy in an orthotopic mouse glioma model.

    Directory of Open Access Journals (Sweden)

    Christian T Farrar

    Full Text Available MRI biomarkers of tumor edema, vascular permeability, blood volume, and average vessel caliber are increasingly being employed to assess the efficacy of tumor therapies. However, the dependence of these biomarkers on a number of physiological factors can compromise their sensitivity and complicate the assessment of therapeutic efficacy. Here we examine the response of these MRI tumor biomarkers to cediranib, a potent vascular endothelial growth factor receptor (VEGFR inhibitor, in an orthotopic mouse glioma model. A significant increase in the tumor volume and relative vessel caliber index (rVCI and a slight decrease in the water apparent diffusion coefficient (ADC were observed for both control and cediranib treated animals. This contrasts with a clinical study that observed a significant decrease in tumor rVCI, ADC and volume with cediranib therapy. While the lack of a difference between control and cediranib treated animals in these biomarker responses might suggest that cediranib has no therapeutic benefit, cediranib treated mice had a significantly increased survival. The increased survival benefit of cediranib treated animals is consistent with the significant decrease observed for cediranib treated animals in the relative cerebral blood volume (rCBV, relative microvascular blood volume (rMBV, transverse relaxation time (T2, blood vessel permeability (K(trans, and extravascular-extracellular space (ν(e. The differential response of pre-clinical and clinical tumors to cediranib therapy, along with the lack of a positive response for some biomarkers, indicates the importance of evaluating the whole spectrum of different tumor biomarkers to properly assess the therapeutic response and identify and interpret the therapy-induced changes in the tumor physiology.

  12. Ecto-5'-Nucleotidase Overexpression Reduces Tumor Growth in a Xenograph Medulloblastoma Model.

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    Angélica R Cappellari

    Full Text Available Ecto-5'-nucleotidase/CD73 (ecto-5'-NT participates in extracellular ATP catabolism by converting adenosine monophosphate (AMP into adenosine. This enzyme affects the progression and invasiveness of different tumors. Furthermore, the expression of ecto-5'-NT has also been suggested as a favorable prognostic marker, attributing to this enzyme contradictory functions in cancer. Medulloblastoma (MB is the most common brain tumor of the cerebellum and affects mainly children.The effects of ecto-5'-NT overexpression on human MB tumor growth were studied in an in vivo model. Balb/c immunodeficient (nude 6 to 14-week-old mice were used for dorsal subcutaneous xenograph tumor implant. Tumor development was evaluated by pathophysiological analysis. In addition, the expression patterns of adenosine receptors were verified.The human MB cell line D283, transfected with ecto-5'-NT (D283hCD73, revealed reduced tumor growth compared to the original cell line transfected with an empty vector. D283hCD73 generated tumors with a reduced proliferative index, lower vascularization, the presence of differentiated cells and increased active caspase-3 expression. Prominent A1 adenosine receptor expression rates were detected in MB cells overexpressing ecto-5'-NT.This work suggests that ecto-5'-NT promotes reduced tumor growth to reduce cell proliferation and vascularization, promote higher differentiation rates and initiate apoptosis, supposedly by accumulating adenosine, which then acts through A1 adenosine receptors. Therefore, ecto-5'-NT might be considered an important prognostic marker, being associated with good prognosis and used as a potential target for therapy.

  13. Ecto-5’-Nucleotidase Overexpression Reduces Tumor Growth in a Xenograph Medulloblastoma Model

    Science.gov (United States)

    Cappellari, Angélica R.; Pillat, Micheli M.; Souza, Hellio D. N.; Dietrich, Fabrícia; Oliveira, Francine H.; Figueiró, Fabrício; Abujamra, Ana L.; Roesler, Rafael; Lecka, Joanna; Sévigny, Jean; Battastini, Ana Maria O.; Ulrich, Henning

    2015-01-01

    Background Ecto-5’-nucleotidase/CD73 (ecto-5’-NT) participates in extracellular ATP catabolism by converting adenosine monophosphate (AMP) into adenosine. This enzyme affects the progression and invasiveness of different tumors. Furthermore, the expression of ecto-5’-NT has also been suggested as a favorable prognostic marker, attributing to this enzyme contradictory functions in cancer. Medulloblastoma (MB) is the most common brain tumor of the cerebellum and affects mainly children. Materials and Methods The effects of ecto-5’-NT overexpression on human MB tumor growth were studied in an in vivo model. Balb/c immunodeficient (nude) 6 to 14-week-old mice were used for dorsal subcutaneous xenograph tumor implant. Tumor development was evaluated by pathophysiological analysis. In addition, the expression patterns of adenosine receptors were verified. Results The human MB cell line D283, transfected with ecto-5’-NT (D283hCD73), revealed reduced tumor growth compared to the original cell line transfected with an empty vector. D283hCD73 generated tumors with a reduced proliferative index, lower vascularization, the presence of differentiated cells and increased active caspase-3 expression. Prominent A1 adenosine receptor expression rates were detected in MB cells overexpressing ecto-5’-NT. Conclusion This work suggests that ecto-5’-NT promotes reduced tumor growth to reduce cell proliferation and vascularization, promote higher differentiation rates and initiate apoptosis, supposedly by accumulating adenosine, which then acts through A1 adenosine receptors. Therefore, ecto-5’-NT might be considered an important prognostic marker, being associated with good prognosis and used as a potential target for therapy. PMID:26491983

  14. Differential superiority of heavy charged-particle irradiation to x-rays: Studies on biological effectivenes and side effect mechanisms in multicellular tumor and normal tissue models

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    Stefan eWalenta

    2016-02-01

    Full Text Available This review is focused on the radiobiology of carbon ions compared to x-rays using multicellular models of tumors and normal mucosa. The first part summarizes basic radiobiological effects, as observed in cancer cells. The second, more clinically oriented part of the review deals with radiation-induced cell migration and mucositis.Multicellular spheroids (MCS from V79 hamster cells were irradiated with x-rays or carbon ions under ambient or restricted oxygen supply conditions. Oxygen enhancement ratios (OER were 2.9, 2.8, and 1.4 for irradiation with photons, 12C+6 in the plateau region, and 12C+6 in the Bragg peak, respectively. A relative biological effectiveness (RBE of 4.3 and 2.1 for ambient pO2 and hypoxia was obtained, respectively. The high effectiveness of carbon ions was reflected by an enhanced accumulation of cells in G2/M, and a dose-dependent massive induction of apoptosis. Clinically relevant doses (3 Gy of x-rays induced an increase in migratory activity of U87 but not of LN229 or HCT116 tumor cells. Such an increase in cell motility following irradiation in situ could be the source of recurrence. In contrast, carbon ion treatment was associated with a dose-dependent decrease in migration with all cell lines and under all conditions investigated. The radiation-induced loss of cell motility was correlated, in most cases, with corresponding changes in 1 integrin expression. Unlike with particles, the photon-induced increase in cell migration was paralleled by an elevated phosphorylation status of the epidermal growth factor receptor (EGFR and AKT-ERK1/2 pathway. Comparing the gene toxicity of x-rays with that of particles using the gamma-H2AX technique in organotypic cultures of the oral mucosa, the superior effectiveness of heavy ions was confirmed by a two-fold higher number of foci per nucleus. Pro-inflammatory signs, however, were similar for both treatment modalities, e. g., the activation of NFkappaB, and the release of IL

  15. Modeling tumor control probability for spatially inhomogeneous risk of failure based on clinical outcome data

    DEFF Research Database (Denmark)

    Lühr, Armin; Löck, Steffen; Jakobi, Annika

    2017-01-01

    PURPOSE: Objectives of this work are (1) to derive a general clinically relevant approach to model tumor control probability (TCP) for spatially variable risk of failure and (2) to demonstrate its applicability by estimating TCP for patients planned for photon and proton irradiation. METHODS...... AND MATERIALS: The approach divides the target volume into sub-volumes according to retrospectively observed spatial failure patterns. The product of all sub-volume TCPi values reproduces the observed TCP for the total tumor. The derived formalism provides for each target sub-volume i the tumor control dose (D...... clinical target volume (CTV), and elective CTV (CTVE). The risk of a local failure in each of these sub-volumes was taken from the literature. RESULTS: Convenient expressions for D50,i and γ50,i were provided for the Poisson and the logistic model. Comparable TCP estimates were obtained for photon...

  16. Periodic and chaotic oscillations in a tumor and immune system interaction model with three delays

    International Nuclear Information System (INIS)

    Bi, Ping; Ruan, Shigui; Zhang, Xinan

    2014-01-01

    In this paper, a tumor and immune system interaction model consisted of two differential equations with three time delays is considered in which the delays describe the proliferation of tumor cells, the process of effector cells growth stimulated by tumor cells, and the differentiation of immune effector cells, respectively. Conditions for the asymptotic stability of equilibria and existence of Hopf bifurcations are obtained by analyzing the roots of a second degree exponential polynomial characteristic equation with delay dependent coefficients. It is shown that the positive equilibrium is asymptotically stable if all three delays are less than their corresponding critical values and Hopf bifurcations occur if any one of these delays passes through its critical value. Numerical simulations are carried out to illustrate the rich dynamical behavior of the model with different delay values including the existence of regular and irregular long periodic oscillations

  17. Hmgb1-IL-23-IL-17-IL-6-Stat3 Axis Promotes Tumor Growth in Murine Models of Melanoma

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    Qiu Tang

    2013-01-01

    Full Text Available In order to understand how tumor cells can escape immune surveillance mechanisms and thus develop antitumor therapies, it is critically important to investigate the mechanisms by which the immune system interacts with the tumor microenvironment. In our current study, IL-17 deficiency results in reduced melanoma tumor size, diminished numbers of proliferating cells and blood vessels, and decreased percentage of CD11b+Gr-1+ MDSCs in tumor tissues. IL-17 promotes IL-6 induction and Stat3 activation. Treatment of Stat3 inhibitor WP1066 in B16-F10 tumor cells inoculated wild-type mice inhibits tumor growth. Additional administration of recombinant IL-6 into B16-F10 tumor-bearing IL-17−/− mice results in markedly increased tumor size and p-Stat3 expression, whereas additional recombinant IL-17 administration into B16-F10 tumor-bearing wild-type mice treated with anti-IL-6 mAb does not significantly alter the tumor growth and p-Stat3 expression. In our further study, blockade of Hmgb1-RAGE pathway inhibits melanoma tumor growth and reduces production of IL-23 and IL-17. All these data suggest that Hmgb1-IL-23-IL-17-IL-6-Stat3 axis plays a pivotal role in tumor development in murine models of melanoma, and blocking any portion of this axis will attenuate melanoma tumor growth.

  18. Modeling tissue contamination to improve molecular identification of the primary tumor site of metastases.

    Science.gov (United States)

    Vincent, Martin; Perell, Katharina; Nielsen, Finn Cilius; Daugaard, Gedske; Hansen, Niels Richard

    2014-05-15

    Contamination of a cancer tissue by the surrounding benign (non-cancerous) tissue is a concern for molecular cancer diagnostics. This is because an observed molecular signature will be distorted by the surrounding benign tissue, possibly leading to an incorrect diagnosis. One example is molecular identification of the primary tumor site of metastases because biopsies of metastases typically contain a significant amount of benign tissue. A model of tissue contamination is presented. This contamination model works independently of the training of a molecular predictor, and it can be combined with any predictor model. The usability of the model is illustrated on primary tumor site identification of liver biopsies, specifically, on a human dataset consisting of microRNA expression measurements of primary tumor samples, benign liver samples and liver metastases. For a predictor trained on primary tumor and benign liver samples, the contamination model decreased the test error on biopsies from liver metastases from 77 to 45%. A further reduction to 34% was obtained by including biopsies in the training data. http://www.math.ku.dk/∼richard/msgl/. vincent@math.ku.dk Supplementary data are available at Bioinformatics online.

  19. 3D bioprinting: improving in vitro models of metastasis with heterogeneous tumor microenvironments

    Science.gov (United States)

    Albritton, Jacob L.

    2017-01-01

    ABSTRACT Even with many advances in treatment over the past decades, cancer still remains a leading cause of death worldwide. Despite the recognized relationship between metastasis and increased mortality rate, surprisingly little is known about the exact mechanism of metastatic progression. Currently available in vitro models cannot replicate the three-dimensionality and heterogeneity of the tumor microenvironment sufficiently to recapitulate many of the known characteristics of tumors in vivo. Our understanding of metastatic progression would thus be boosted by the development of in vitro models that could more completely capture the salient features of cancer biology. Bioengineering groups have been working for over two decades to create in vitro microenvironments for application in regenerative medicine and tissue engineering. Over this time, advances in 3D printing technology and biomaterials research have jointly led to the creation of 3D bioprinting, which has improved our ability to develop in vitro models with complexity approaching that of the in vivo tumor microenvironment. In this Review, we give an overview of 3D bioprinting methods developed for tissue engineering, which can be directly applied to constructing in vitro models of heterogeneous tumor microenvironments. We discuss considerations and limitations associated with 3D printing and highlight how these advances could be harnessed to better model metastasis and potentially guide the development of anti-cancer strategies. PMID:28067628

  20. Optimizing Chemotherapeutic Anti-cancer Treatment and the Tumor Microenvironment: An Analysis of Mathematical Models.

    Science.gov (United States)

    Ledzewicz, Urszula; Schaettler, Heinz

    2016-01-01

    We review results about the structure of administration of chemotherapeutic anti-cancer treatment that we have obtained from an analysis of minimally parameterized mathematical models using methods of optimal control. This is a branch of continuous-time optimization that studies the minimization of a performance criterion imposed on an underlying dynamical system subject to constraints. The scheduling of anti-cancer treatments has all the features of such a problem: treatments are administered in time and the interactions of the drugs with the tumor and its microenvironment determine the efficacy of therapy. At the same time, constraints on the toxicity of the treatments need to be taken into account. The models we consider are low-dimensional and do not include more refined details, but they capture the essence of the underlying biology and our results give robust and rather conclusive qualitative information about the administration of optimal treatment protocols that strongly correlate with approaches taken in medical practice. We describe the changes that arise in optimal administration schedules as the mathematical models are increasingly refined to progress from models that only consider the cancerous cells to models that include the major components of the tumor microenvironment, namely the tumor vasculature and tumor-immune system interactions.

  1. 3D bioprinting: improving in vitro models of metastasis with heterogeneous tumor microenvironments

    Directory of Open Access Journals (Sweden)

    Jacob L. Albritton

    2017-01-01

    Full Text Available Even with many advances in treatment over the past decades, cancer still remains a leading cause of death worldwide. Despite the recognized relationship between metastasis and increased mortality rate, surprisingly little is known about the exact mechanism of metastatic progression. Currently available in vitro models cannot replicate the three-dimensionality and heterogeneity of the tumor microenvironment sufficiently to recapitulate many of the known characteristics of tumors in vivo. Our understanding of metastatic progression would thus be boosted by the development of in vitro models that could more completely capture the salient features of cancer biology. Bioengineering groups have been working for over two decades to create in vitro microenvironments for application in regenerative medicine and tissue engineering. Over this time, advances in 3D printing technology and biomaterials research have jointly led to the creation of 3D bioprinting, which has improved our ability to develop in vitro models with complexity approaching that of the in vivo tumor microenvironment. In this Review, we give an overview of 3D bioprinting methods developed for tissue engineering, which can be directly applied to constructing in vitro models of heterogeneous tumor microenvironments. We discuss considerations and limitations associated with 3D printing and highlight how these advances could be harnessed to better model metastasis and potentially guide the development of anti-cancer strategies.

  2. Tumor-derived exosomes confer antigen-specific immunosuppression in a murine delayed-type hypersensitivity model.

    Directory of Open Access Journals (Sweden)

    Chenjie Yang

    Full Text Available Exosomes are endosome-derived small membrane vesicles that are secreted by most cell types including tumor cells. Tumor-derived exosomes usually contain tumor antigens and have been used as a source of tumor antigens to stimulate anti-tumor immune responses. However, many reports also suggest that tumor-derived exosomes can facilitate tumor immune evasion through different mechanisms, most of which are antigen-independent. In the present study we used a mouse model of delayed-type hypersensitivity (DTH and demonstrated that local administration of tumor-derived exosomes carrying the model antigen chicken ovalbumin (OVA resulted in the suppression of DTH response in an antigen-specific manner. Analysis of exosome trafficking demonstrated that following local injection, tumor-derived exosomes were internalized by CD11c+ cells and transported to the draining LN. Exosome-mediated DTH suppression is associated with increased mRNA levels of TGF-β1 and IL-4 in the draining LN. The tumor-derived exosomes examined were also found to inhibit DC maturation. Taken together, our results suggest a role for tumor-derived exosomes in inducing tumor antigen-specific immunosuppression, possibly by modulating the function of APCs.

  3. Osteopontin induces growth of metastatic tumors in a preclinical model of non-small lung cancer

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    Shojaei Farbod

    2012-03-01

    Full Text Available Abstract Osteopontin (OPN, also known as SPP1 (secreted phosphoprotein, is an integrin binding glyco-phosphoprotein produced by a variety of tissues. In cancer patients expression of OPN has been associated with poor prognosis in several tumor types including breast, lung, and colorectal cancers. Despite wide expression in tumor cells and stroma, there is limited evidence supporting role of OPN in tumor progression and metastasis. Using phage display technology we identified a high affinity anti-OPN monoclonal antibody (hereafter AOM1. The binding site for AOM1 was identified as SVVYGLRSKS sequence which is immediately adjacent to the RGD motif and also spans the thrombin cleavage site of the human OPN. AOM1 efficiently inhibited OPNa binding to recombinant integrin αvβ3 with an IC50 of 65 nM. Due to its unique binding site, AOM1 is capable of inhibiting OPN cleavage by thrombin which has been shown to produce an OPN fragment that is biologically more active than the full length OPN. Screening of human cell lines identified tumor cells with increased expression of OPN receptors (αvβ3 and CD44v6 such as mesothelioma, hepatocellular carcinoma, breast, and non-small cell lung adenocarcinoma (NSCLC. CD44v6 and αvβ3 were also found to be highly enriched in the monocyte, but not lymphocyte, subset of human peripheral blood mononuclear cells (hPBMCs. In vitro, OPNa induced migration of both tumor and hPBMCs in a transwell migration assay. AOM1 significantly blocked cell migration further validating its specificity for the ligand. OPN was found to be enriched in mouse plasma in a number of pre-clinical tumor model of non-small cell lung cancers. To assess the role of OPN in tumor growth and metastasis and to evaluate a potential therapeutic indication for AOM1, we employed a KrasG12D-LSLp53fl/fl subcutaneously implanted in vivo model of NSCLC which possesses a high capacity to metastasize into the lung. Our data indicated that treatment of tumor

  4. Fluorescence laparoscopy imaging of pancreatic tumor progression in an orthotopic mouse model

    Science.gov (United States)

    Tran Cao, Hop S.; Kaushal, Sharmeela; Lee, Claudia; Snyder, Cynthia S.; Thompson, Kari J.; Horgan, Santiago; Talamini, Mark A.; Hoffman, Robert M.

    2010-01-01

    Background The use of fluorescent proteins to label tumors is revolutionizing cancer research, enabling imaging of both primary and metastatic lesions, which is important for diagnosis, staging, and therapy. This report describes the use of fluorescence laparoscopy to image green fluorescent protein (GFP)-expressing tumors in an orthotopic mouse model of human pancreatic cancer. Methods The orthotopic mouse model of human pancreatic cancer was established by injecting GFP-expressing MiaPaCa-2 human pancreatic cancer cells into the pancreas of 6-week-old female athymic mice. On postoperative day 14, diagnostic laparoscopy using both white and fluorescent light was performed. A standard laparoscopic system was modified by placing a 480-nm short-pass excitation filter between the light cable and the laparoscope in addition to using a 2-mm-thick emission filter. A camera was used that allowed variable exposure time and gain setting. For mouse laparoscopy, a 3-mm 0° laparoscope was used. The mouse’s abdomen was gently insufflated to 2 mm Hg via a 22-gauge angiocatheter. After laparoscopy, the animals were sacrificed, and the tumors were collected and processed for histologic review. The experiments were performed in triplicate. Results Fluorescence laparoscopy enabled rapid imaging of the brightly fluorescent tumor in the pancreatic body. Use of the proper filters enabled simultaneous visualization of the tumor and the surrounding structures with minimal autofluorescence. Fluorescence laparoscopy thus allowed exact localization of the tumor, eliminating the need to switch back and forth between white and fluorescence lighting, under which the background usually is so darkened that it is difficult to maintain spatial orientation. Conclusion The use of fluorescence laparoscopy permits the facile, real-time imaging and localization of tumors labeled with fluorescent proteins. The results described in this report should have important clinical potential. PMID:20533064

  5. Effective treatment of diverse medulloblastoma models with mebendazole and its impact on tumor angiogenesis.

    Science.gov (United States)

    Bai, Ren-Yuan; Staedtke, Verena; Rudin, Charles M; Bunz, Fred; Riggins, Gregory J

    2015-04-01

    Medulloblastoma is the most common malignant brain tumor in children. Current standard treatments cure 40%-60% of patients, while the majority of survivors suffer long-term neurological sequelae. The identification of 4 molecular groups of medulloblastoma improved the clinical management with the development of targeted therapies; however, the tumor acquires resistance quickly. Mebendazole (MBZ) has a long safety record as antiparasitic in children and has been recently implicated in inhibition of various tyrosine kinases in vitro. Here, we investigated the efficacy of MBZ in various medulloblastoma subtypes and MBZ's impact on vascular endothelial growth factor receptor 2 (VEGFR2) and tumor angiogenesis. The inhibition of MBZ on VEGFR2 kinase was investigated in an autophosphorylation assay and a cell-free kinase assay. Mice bearing orthotopic PTCH1-mutant medulloblastoma allografts, a group 3 medulloblastoma xenograft, and a PTCH1-mutant medulloblastoma with acquired resistance to the smoothened inhibitor vismodegib were treated with MBZ. The survival benefit and the impact on tumor angiogenesis and VEGFR2 kinase function were analyzed. We determined that MBZ interferes with VEGFR2 kinase by competing with ATP. MBZ selectively inhibited tumor angiogenesis but not the normal brain vasculatures in orthotopic medulloblastoma models and suppressed VEGFR2 kinase in vivo. MBZ significantly extended the survival of medulloblastoma models derived from different molecular backgrounds. Our findings support testing of MBZ as a possible low-toxicity therapy for medulloblastomas of various molecular subtypes, including tumors with acquired vismodegib resistance. Its antitumor mechanism may be partially explained by inhibition of tumor angiogenesis. © The Author(s) 2014. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  6. Further evidence for the absence of a hypoxic fraction in the 9L rat tumour multicellular spheroid system

    International Nuclear Information System (INIS)

    Gutin, P.H.; Barcellos, M.H.; Shrieve, D.C.; Sano, Y.; Bernstein, M.; Deen, D.F.

    1982-01-01

    The 9L gliosarcoma is an N-methylnitrosourea-induced rat brain tumour that has served as a predictive model for the efficacy of various chemotherapeutic agents against human brain tumours. Because it is one of two known animal tumour models that has no hypoxic fraction, the 9L model is of questionable value for the study of the radiobiology of hypoxic cell sensitizers. Hypoxic 9L monolayer cells are sensitive to misonidazole, as shown by the abrupt decrease in survival after a 2-4 h radiation exposure. However, when 9L spheroids in the size ranges of 200-300, 300-400, 500-600 and 1027+-33μm were incubated in euoxic spinner culture for up to 96 h in 1.5 or 3.0 mM misonidazole, there was no effect on the survival of the dissociated cells over a dose range 0-20 Gy. It is concluded that, in view of the demonstrated sensitivity to misonidazole of hypoxic 9L cells in monolayer culture, this finding provides further evidence that there are no hypoxic cells even in large 9L spheroids with a histologically distinct zone of central necrosis. Moreover, 9L spheroids irradiated in the presence of 3.0 mM misonidazole showed no dose enhancement. (U.K.)

  7. Automatic Lung Tumor Segmentation on PET/CT Images Using Fuzzy Markov Random Field Model

    Directory of Open Access Journals (Sweden)

    Yu Guo

    2014-01-01

    Full Text Available The combination of positron emission tomography (PET and CT images provides complementary functional and anatomical information of human tissues and it has been used for better tumor volume definition of lung cancer. This paper proposed a robust method for automatic lung tumor segmentation on PET/CT images. The new method is based on fuzzy Markov random field (MRF model. The combination of PET and CT image information is achieved by using a proper joint posterior probability distribution of observed features in the fuzzy MRF model which performs better than the commonly used Gaussian joint distribution. In this study, the PET and CT simulation images of 7 non-small cell lung cancer (NSCLC patients were used to evaluate the proposed method. Tumor segmentations with the proposed method and manual method by an experienced radiation oncologist on the fused images were performed, respectively. Segmentation results obtained with the two methods were similar and Dice’s similarity coefficient (DSC was 0.85 ± 0.013. It has been shown that effective and automatic segmentations can be achieved with this method for lung tumors which locate near other organs with similar intensities in PET and CT images, such as when the tumors extend into chest wall or mediastinum.

  8. Evaluation of cloned cells, animal model, and ATRA sensitivity of human testicular yolk sac tumor

    Directory of Open Access Journals (Sweden)

    Zhao Junfeng

    2012-03-01

    Full Text Available Abstract The testicular yolk sac tumor (TYST is the most common neoplasm originated from germ cells differentiated abnormally, a major part of pediatric malignant testicular tumors. The present study aimed at developing and validating the in vitro and vivo models of TYST and evaluating the sensitivity of TYST to treatments, by cloning human TYST cells and investigating the histology, ultra-structure, growth kinetics and expression of specific proteins of cloned cells. We found biological characteristics of cloned TYST cells were similar to the yolk sac tumor and differentiated from the columnar to glandular-like or goblet cells-like cells. Chromosomes for tumor identification in each passage met nature of the primary tumor. TYST cells were more sensitive to all-trans-retinoic acid which had significantly inhibitory effects on cell proliferation. Cisplatin induced apoptosis of TYST cells through the activation of p53 expression and down-regulation of Bcl- expression. Thus, we believe that cloned TYST cells and the animal model developed here are useful to understand the molecular mechanism of TYST cells and develop potential therapies for human TYST.

  9. Effect of hepatic artery embolization on liver hypertrophy response in a rabbit liver VX2 tumor model.

    Science.gov (United States)

    van Lienden, Krijn P; Hoekstra, Lisette T; van Trigt, Jessica D; Roelofs, Joris J; van Delden, Otto M; van Gulik, Thomas M

    2013-12-01

    Portal vein embolization not only induces hypertrophy of the non-embolized liver, but also enhances tumor growth. The latter could be prevented by embolizing the hepatic arteries supplying the tumor-bearing liver segments. This study aimed to determine the effects of transcatheter arterial embolization (TAE) on tumor volume and liver regeneration in a rabbit VX2 tumor model. Twenty-three rabbits underwent subcapsular tumor implantation with a VX2 tumor. Two weeks after implantation, 18 rabbits were used for TAE experiments, 5 were for sham controls. Tumor response and liver regeneration response of the embolized cranial and non-embolized caudal liver lobes were assessed by CT volumetry, liver to body weight index, and the amount of proliferating hepatocytes. All super-selective arterial tumor embolization procedures were performed successfully. Despite embolization, the tumor volume increased after an initial steady state. The tumor volume after embolization was smaller than that of the sham group, but this difference was not significant. Massive necrosis of the tumor, however, was seen after embolization, without damage of the surrounding liver parenchyma. There was a significant atrophy response of the tumor bearing cranial lobe after super-selective arterial embolization of the tumor with a concomitant hypertrophy response of the non-embolized, caudal lobe. This regeneration response was confirmed histologically by a significantly higher number of proliferating hepatocytes on the Ki-67 stained slides. Super-selective, bland arterial coil embolization causes massive necrosis of the tumor, despite increase of volume on CT scan. Atrophy of the tumor bearing liver lobe is seen after arterial embolization of the tumor with a concomitant hypertrophy response of the non-embolized lobe, despite absence of histological damage of the tumor-surrounding liver parenchyma.

  10. Analysis of a diffuse interface model of multispecies tumor growth

    Czech Academy of Sciences Publication Activity Database

    Dai, M.; Feireisl, Eduard; Rocca, E.; Schimperna, G.; Schonbek, M.E.

    2017-01-01

    Roč. 30, č. 4 (2017), s. 1639-1658 ISSN 0951-7715 EU Projects: European Commission(XE) 320078 - MATHEF Institutional support: RVO:67985840 Keywords : Cahn-Hilliard equation * Darcy law * diffuse interface model Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 1.767, year: 2016 http://iopscience.iop.org/article/10.1088/1361-6544/aa6063/meta

  11. Establishment of a Novel Model for Anticancer Drug Resistance in Three-Dimensional Primary Culture of Tumor Microenvironment

    Directory of Open Access Journals (Sweden)

    Tatsuya Usui

    2016-01-01

    Full Text Available Tumor microenvironment has been implicated in tumor development and progression. As a three-dimensional tumor microenvironment model, air liquid interface (ALI organoid culture from oncogene transgenic mouse gastrointestinal tissues was recently produced. However, ALI organoid culture system from tissues of colorectal cancer patients has not been established. Here, we developed an ALI organoid model from normal and tumor colorectal tissues of human patients. Both organoids were successfully generated and showed cystic structures containing an epithelial layer and surrounding mesenchymal stromal cells. Structures of tumor organoids closely resembled primary tumor epithelium. Expression of an epithelial cell marker, E-cadherin, a goblet cell marker, MUC2, and a fibroblast marker, vimentin, but not a myofibroblast marker, α-smooth muscle actin (SMA, was observed in normal organoids. Expression of E-cadherin, MUC2, vimentin, and α-SMA was observed in tumor organoids. Expression of a cancer stem cell marker, LGR5 in tumor organoids, was higher than that in primary tumor tissues. Tumor organoids were more resistant to toxicity of 5-fluorouracil and Irinotecan than colorectal cancer cell lines, SW480, SW620, and HCT116. These findings indicate that ALI organoid culture from colorectal cancer patients may become a novel model that is useful for examining resistance to chemotherapy in tumor microenvironment.

  12. Relations between pH, oxygen partial pressure and growth in cultured cell spheroids.

    Science.gov (United States)

    Carlsson, J; Acker, H

    1988-11-15

    The pH gradients, oxygen partial-pressure gradients and growth curves were measured for 7 different types of spheroids. Growth curves were measured in liquid overlay culture and thereafter the spheroids were attached to cover glasses and transferred to a chamber for micro-electrode measurements. The spheroids were randomly divided for pH or pO2 measurements which then were made under conditions as identical as possible. The decreases in pO2 and pH, delta pO2 and delta pH were calculated as the difference between the values in the culture medium and the values 200 micron inside the spheroids. Each type of spheroid had a certain relation between delta pO2 and delta pH. The human colon carcinoma HT29, the mouse mammary carcinoma EMT6 and the hamster lung V79-379A spheroids had high values of the quotient delta pO2/delta pH. The human thyroid carcinoma HTh7 spheroids and the 3 types of human glioma spheroids had lower quotients. There was a tendency for fast-growing spheroids to have high quotients. Two extreme types of spheroids, HT29 (high quotient) and U-118 MG (low quotient) were analyzed for lactate production and oxygen consumption. The U-118 MG spheroids produced about 3 times more lactate and consumed about 3 times less oxygen than the HT29 spheroids. The differences in lactate production could not be explained by differences in the pyruvate Km values of lactate dehydrogenase. The results indicate that there are significant metabolic differences between the spheroid systems studied.

  13. Dissociation of mono- and co-culture spheroids into single cells for subsequent flow cytometric analysis.

    Science.gov (United States)

    Grässer, Ute; Bubel, Monika; Sossong, Daniela; Oberringer, Martin; Pohlemann, Tim; Metzger, Wolfgang

    2018-03-01

    Spheroids are considered to reflect the natural organization of cells better than 2D cell cultures, but their analysis by flow cytometry requires dissociation into single cells. We established protocols for dissociation of mono- and co-culture spheroids consisting of human fibroblasts and human endothelial cells. Cell recovery rate and viability after dissociation were evaluated with hemocytometer and by flow cytometry. The diameter of cells and the amount of cell aggregates were quantified by Casy ® -technology and the cellular composition was analyzed by flow cytometry. Optimal dissociation conditions with low cell aggregation were determined by size, cultivation time and cellular composition of the spheroids. Smaller spheroids (10,000 cells) could be dissociated with Accutase ® , whereas larger spheroids (50,000 cells) required more stringent dissociation conditions. The size of the cells decreased with increasing cultivation time. Cell recovery rate was dependent upon cellular composition and spheroid size. The highest cell recovery rate was found for co-culture spheroids. The highest cell viability was detected for dissociated fibroblast spheroids. A quantitative analysis of the cellular composition of dissociated co-culture spheroids was possible. Spheroids can be successfully dissociated into singular cells for subsequent flow cytometric analysis. Dissociation conditions as well as cell recovery rate and cell viability depend on size, cultivation time and cellular composition of the spheroids. The observed decrease in cell size in spheroids over time might be responsible for the well-known time-dependent decrease in spheroid size. Copyright © 2017 Elsevier GmbH. All rights reserved.

  14. Establishment of 9L/F344 rat intracerebral glioma model of brain tumor stem cells

    Directory of Open Access Journals (Sweden)

    Zong-yu XIAO

    2015-04-01

    Full Text Available Objective To establish the 9L/F344 rat intracerebral glioma model of brain tumor stem cells.  Methods Rat 9L gliosarcoma stem-like cells were cultured in serum-free suspension. The expression of CD133 and nestin were tested by immunohistochemistry. A total of 48 inbredline male F344 rats were randomly divided into 2 groups, and 9L tumor sphere cells and 9L monolayer cells were respectively implanted into the right caudate nucleus of F344 rats in 2 groups. Survival time was observed and determined using the method of Kaplan-Meier survival analysis. Fourteen days after implantation or when the rats were dying, their brains were perfused and sectioned for HE staining, and CD133 and nestin were detected by immunohistochemistry.  Results Rat 9L tumor spheres were formed with suspension culture in serum-free medium. The gliomas formed in both groups were invasive without obvious capsule. More new vessels, bleeding and necrosis could be detected in 9L tumor spheres group. The tumor cells in both groups were positive for CD133 and nestin. There was no significant difference in the expression of CD133 and nestin between 2 groups (P > 0.05, for all. According to the expression of nestin, the tumors formed by 9L tumor sphere cells were more invasive. The median survival time of the rats bearing 9L tumor sphere cells was 15 d (95%CI: 15.219-15.781, and the median survival time of the rats bearing 9L monolayer cells was 21 d (95%CI: 20.395-21.605. There was significant difference between 2 groups (χ2 = 12.800, P = 0.000.  Conclusions 9L/F344 rat intracerebral glioma model of brain tumor stem cells is successfully established, which provides a glioma model for the future research. DOI: 10.3969/j.issn.1672-6731.2015.04.012

  15. A Gaussian mixture model for definition of lung tumor volumes in positron emission tomography

    International Nuclear Information System (INIS)

    Aristophanous, Michalis; Penney, Bill C.; Martel, Mary K.; Pelizzari, Charles A.

    2007-01-01

    The increased interest in 18 F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in radiation treatment planning in the past five years necessitated the independent and accurate segmentation of gross tumor volume (GTV) from FDG-PET scans. In some studies the radiation oncologist contours the GTV based on a computed tomography scan, while incorporating pertinent data from the PET images. Alternatively, a simple threshold, typically 40% of the maximum intensity, has been employed to differentiate tumor from normal tissue, while other researchers have developed algorithms to aid the PET based GTV definition. None of these methods, however, results in reliable PET tumor segmentation that can be used for more sophisticated treatment plans. For this reason, we developed a Gaussian mixture model (GMM) based segmentation technique on selected PET tumor regions from non-small cell lung cancer patients. The purpose of this study was to investigate the feasibility of using a GMM-based tumor volume definition in a robust, reliable and reproducible way. A GMM relies on the idea that any distribution, in our case a distribution of image intensities, can be expressed as a mixture of Gaussian densities representing different classes. According to our implementation, each class belongs to one of three regions in the image; the background (B), the uncertain (U) and the target (T), and from these regions we can obtain the tumor volume. User interaction in the implementation is required, but is limited to the initialization of the model parameters and the selection of an ''analysis region'' to which the modeling is restricted. The segmentation was developed on three and tested on another four clinical cases to ensure robustness against differences observed in the clinic. It also compared favorably with thresholding at 40% of the maximum intensity and a threshold determination function based on tumor to background image intensities proposed in a recent paper. The parts of the

  16. Immunological considerations of modern animal models of malignant primary brain tumors

    Directory of Open Access Journals (Sweden)

    James C David

    2009-10-01

    Full Text Available Abstract Recent advances in animal models of glioma have facilitated a better understanding of biological mechanisms underlying gliomagenesis and glioma progression. The limitations of existing therapy, including surgery, chemotherapy, and radiotherapy, have prompted numerous investigators to search for new therapeutic approaches to improve quantity and quality of survival from these aggressive lesions. One of these approaches involves triggering a tumor specific immune response. However, a difficulty in this approach is the the scarcity of animal models of primary CNS neoplasms which faithfully recapitulate these tumors and their interaction with the host's immune system. In this article, we review the existing methods utilized to date for modeling gliomas in rodents, with a focus on the known as well as potential immunological aspects of these models. As this review demonstrates, many of these models have inherent immune system limitations, and the impact of these limitations on studies on the influence of pre-clinical therapeutics testing warrants further attention.

  17. Eutectic solidification mode of spheroidal graphite cast iron and graphitization

    Directory of Open Access Journals (Sweden)

    Hideo Nakae

    2007-02-01

    Full Text Available The shrinkage and chilling tendency of spheroidal graphite (abbreviated SG cast iron is much greater than that of the flake graphite cast iron in spite of its higher amount of C and Si contents. Why? The main reason should be the difference in their graphitization during the eutectic solidification. In this paper, we discuss the difference in the solidification mechanism of both cast irons for solving these problems using unidirectional solidification and the cooling curves of the spheroidal graphite cast iron. The eutectic solidification rate of the SG cast iron is controlled by the diffusion of carbon through the austenite shell, and the final thickness is 1.4 times the radius of the SG, therefore, the reduction of the SG size, namely, the increase in the number, is the main solution of these problems.

  18. Glioma Cells in the Tumor Periphery Have a Stem Cell Phenotype.

    Directory of Open Access Journals (Sweden)

    Sune Munthe

    Full Text Available Gliomas are highly infiltrative tumors incurable with surgery. Although surgery removes the bulk tumor, tumor cells in the periphery are left behind resulting in tumor relapses. The aim of the present study was to characterize the phenotype of tumor cells in the periphery focusing on tumor stemness, proliferation and chemo-resistance. This was investigated in situ in patient glioma tissue as well as in orthotopic glioblastoma xenografts. We identified 26 gliomas having the R132 mutation in Isocitrate DeHydrogenase 1 (mIDH1. A double immunofluorescence approach identifying mIDH1 positive tumor cells and a panel of markers was used. The panel comprised of six stem cell-related markers (CD133, Musashi-1, Bmi-1, Sox-2, Nestin and Glut-3, a proliferation marker (Ki-67 as well as a chemo-resistance marker (MGMT. Computer-based automated classifiers were designed to measure the mIDH1 positive nucleus area-fraction of the chosen markers. Moreover, orthotopic glioblastoma xenografts from five different patient-derived spheroid cultures were obtained and the tumor cells identified by human specific immunohistochemical markers. The results showed that tumor cells in the periphery of patient gliomas expressed stem cell markers, however for most markers at a significantly lower level than in the tumor core. The Ki-67 level was slightly reduced in the periphery, whereas the MGMT level was similar. In orthotopic glioblastoma xenografts all markers showed similar levels in the core and periphery. In conclusion tumor cells in the periphery of patient gliomas have a stem cell phenotype, although it is less pronounced than in the tumor core. Novel therapies aiming at preventing recurrence should therefore take tumor stemness into account. Migrating cells in orthotopic glioblastoma xenografts preserve expression and stem cell markers. The orthotopic model therefore has a promising translational potential.

  19. Analysis of a diffuse interface model of multispecies tumor growth

    Czech Academy of Sciences Publication Activity Database

    Dai, M.; Feireisl, Eduard; Rocca, E.; Schimperna, G.; Schonbek, M.E.

    2017-01-01

    Roč. 30, č. 4 (2017), s. 1639-1658 ISSN 0951-7715 EU Projects: European Commission(XE) 320078 - MATHEF Institutional support: RVO:67985840 Keywords : Cahn-Hilliard equation * Darcy law * diffuse interface model Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 1.767, year: 2016 http://iopscience.iop.org/article/10.1088/1361-6544/aa6063/meta;jsessionid=73B30CFD9F74DD027762D29C83D3094F.c3.iopscience.cld.iop.org

  20. Selenium prevents tumor development in a rat model for chemical carcinogenesis

    DEFF Research Database (Denmark)

    Bjorkhem-Bergman, L.; Torndal, U. B.; Eken, S.

    2005-01-01

    for chemically induced hepatocarcinogenesis, the resistant hepatocyte model. Selenite in supra-nutritional but subtoxic doses (1 and 5 p.p.m.) was administrated to the animals through the drinking water. Such supplementation during the initiation phase did not have a tumor preventive effect. However, selenite...

  1. Current advances in mathematical modeling of anti-cancer drug penetration into tumor tissues.

    Science.gov (United States)

    Kim, Munju; Gillies, Robert J; Rejniak, Katarzyna A

    2013-11-18

    Delivery of anti-cancer drugs to tumor tissues, including their interstitial transport and cellular uptake, is a complex process involving various biochemical, mechanical, and biophysical factors. Mathematical modeling provides a means through which to understand this complexity better, as well as to examine interactions between contributing components in a systematic way via computational simulations and quantitative analyses. In this review, we present the current state of mathematical modeling approaches that address phenomena related to drug delivery. We describe how various types of models were used to predict spatio-temporal distributions of drugs within the tumor tissue, to simulate different ways to overcome barriers to drug transport, or to optimize treatment schedules. Finally, we discuss how integration of mathematical modeling with experimental or clinical data can provide better tools to understand the drug delivery process, in particular to examine the specific tissue- or compound-related factors that limit drug penetration through tumors. Such tools will be important in designing new chemotherapy targets and optimal treatment strategies, as well as in developing non-invasive diagnosis to monitor treatment response and detect tumor recurrence.

  2. Toward in vivo lung's tissue incompressibility characterization for tumor motion modeling in radiation therapy