Antioxidant oils and Salmonella enterica Typhimurium reduce tumor in an experimental model of hepatic metastasis

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Sorenson BS

2011-05-01

Full Text Available Brent S Sorenson, Kaysie L Banton, Lance B Augustin, Arnold S Leonard, Daniel A SaltzmanDepartment of Surgery, University of Minnesota Medical School, Minneapolis, MN, USAAbstract: Fruit seeds high in antioxidants have been shown to have anticancer properties and enhance host protection against microbial infection. Recently we showed that a single oral dose of Salmonella enterica serovar Typhimurium expressing a truncated human interleukin-2 gene (SalpIL2 is avirulent, immunogenic, and reduces hepatic metastases through increased natural killer cell populations in mice. To determine whether antioxidant compounds enhance the antitumor effect seen in SalpIL2-treated animals, we assayed black cumin (BC, black raspberry (BR, and milk thistle (MT seed oils for the ability to reduce experimental hepatic metastases in mice. In animals without tumor, BC and BR oil diets altered the kinetics of the splenic lymphocyte response to SalpIL2. Consistent with previous reports, BR and BC seed oils demonstrated independent antitumor properties and moderate adjuvant potential with SalpIL2. MT oil, however, inhibited the efficacy of SalpIL2 in our model. Based on these data, we conclude that a diet high in antioxidant oils promoted a more robust immune response to SalpIL2, thus enhancing its antitumor efficacy.Keywords: antioxidants, colorectal cancer, tumor models, metastasis

Stochastic models for tumoral growth

OpenAIRE

Escudero, Carlos

2006-01-01

Strong experimental evidence has indicated that tumor growth belongs to the molecular beam epitaxy universality class. This type of growth is characterized by the constraint of cell proliferation to the tumor border, and surface diffusion of cells at the growing edge. Tumor growth is thus conceived as a competition for space between the tumor and the host, and cell diffusion at the tumor border is an optimal strategy adopted for minimizing the pressure and helping tumor development. Two stoch...

A comparative study of 99mTc-HL91 and 99mTc-MIBI imaging in experimental tumor and inflammatory models

International Nuclear Information System (INIS)

Cao, W.; Zhang, X.Y.; An, R.

2002-01-01

Aim: 99m Tc-HL91 is a newly developed hypoxic imaging agent for ischemic myocardium and tumor imaging. 99m Tc-MIBI is one of imaging agent for mammary tumor imaging. The aim of this experiment is to evaluate the diagnostic value of 99m Tc-HL91 in detection of solid tumor in experimental tumor and inflammatory models, via comparative study with 99m Tc-MIBI. Material and Methods: HL91 kits was provided by China Nine Star Co. Three kinds of bearing solid neoplasm mice groups (bearing Ehrlich carcinoma mice, bearing H 22 carcinoma mice and bearing human ovarian COC 1 neoplasm nude mice) and two inflammatory model groups (chemical and bacterial inflammation) underwent static whole body planar images at 1 and 4 hours post injection of 99m Tc-HL91. Two kinds of bearing neoplasm mice groups (bearing Ehrlich carcinoma mice, bearing H 22 carcinoma mice) and two inflammatory model groups (chemical and bacterial inflammation) underwent static planar images post injection of 99m Tc-MIBI, at early phase (10∼20 minutes) and delayed phase (2 hrs). All of mice were sacrificed at 4 hrs. The tumors, or inflammatory lesions, blood and contralateral muscles were removed, weighed and the radioactivity was measured. Regions of interesting (ROIs) were drawn around tumor, inflammatory lesions and contralateral muscles in planar images, and the radioactivity ratios of target (tumor or inflammatory lesions)-to-blood (T/B), target-to-non target (contralateral muscles) i. e. T/NT was calculated. Results: Neoplasm can be clearly visible in planar images at 1hr and 4 hrs post injection of 99m Tc-HL91 in all tumor models. At same time inflammatory lesions cannot be seen clearly. Neoplasm can be seen in delayed phase in 99m Tc-MIBI groups, but not easy to distinguish them from inflammation. Conclusion: Compared with 99m Tc-MIBI imaging, 99m Tc-HL91 has much more diagnostic value in detection of solid neoplasm, and can distinguish neoplasm from inflammation

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

Modeling evolutionary dynamics of epigenetic mutations in hierarchically organized tumors.

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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.

Experimental data and dose-response models

International Nuclear Information System (INIS)

Ullrich, R.L.

1985-01-01

Dose-response relationships for radiation carcinogenesis have been of interest to biologists, modelers, and statisticians for many years. Despite his interest there are few instances in which there are sufficient experimental data to allow the fitting of various dose-response models. In those experimental systems for which data are available the dose-response curves for tumor induction for the various systems cannot be described by a single model. Dose-response models which have been observed following acute exposures to gamma rays include threshold, quadratic, and linear models. Data on sex, age, and environmental influences of dose suggest a strong role of host factors on the dose response. With decreasing dose rate the effectiveness of gamma ray irradiation tends to decrease in essentially every instance. In those cases in which the high dose rate dose response could be described by a quadratic model, the effect of dose rate is consistent with predictions based on radiation effects on the induction of initial events. Whether the underlying reasons for the observed dose-rate effect is a result of effects on the induction of initial events or is due to effects on the subsequent steps in the carcinogenic process is unknown. Information on the dose response for tumor induction for high LET (linear energy transfer) radiations such as neutrons is even more limited. The observed dose and dose rate data for tumor induction following neutron exposure are complex and do not appear to be consistent with predictions based on models for the induction of initial events

Tissue engineered tumor models.

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Ingram, M; Techy, G B; Ward, B R; Imam, S A; Atkinson, R; Ho, H; Taylor, C R

2010-08-01

Many research programs use well-characterized tumor cell lines as tumor models for in vitro studies. Because tumor cells grown as three-dimensional (3-D) structures have been shown to behave more like tumors in vivo than do cells growing in monolayer culture, a growing number of investigators now use tumor cell spheroids as models. Single cell type spheroids, however, do not model the stromal-epithelial interactions that have an important role in controlling tumor growth and development in vivo. We describe here a method for generating, reproducibly, more realistic 3-D tumor models that contain both stromal and malignant epithelial cells with an architecture that closely resembles that of tumor microlesions in vivo. Because they are so tissue-like we refer to them as tumor histoids. They can be generated reproducibly in substantial quantities. The bioreactor developed to generate histoid constructs is described and illustrated. It accommodates disposable culture chambers that have filled volumes of either 10 or 64 ml, each culture yielding on the order of 100 or 600 histoid particles, respectively. Each particle is a few tenths of a millimeter in diameter. Examples of histological sections of tumor histoids representing cancers of breast, prostate, colon, pancreas and urinary bladder are presented. Potential applications of tumor histoids include, but are not limited to, use as surrogate tumors for pre-screening anti-solid tumor pharmaceutical agents, as reference specimens for immunostaining in the surgical pathology laboratory and use in studies of invasive properties of cells or other aspects of tumor development and progression. Histoids containing nonmalignant cells also may have potential as "seeds" in tissue engineering. For drug testing, histoids probably will have to meet certain criteria of size and tumor cell content. Using a COPAS Plus flow cytometer, histoids containing fluorescent tumor cells were analyzed successfully and sorted using such criteria.

Numerical Simulation of a Tumor Growth Dynamics Model Using Particle Swarm Optimization.

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Wang, Zhijun; Wang, Qing

Tumor cell growth models involve high-dimensional parameter spaces that require computationally tractable methods to solve. To address a proposed tumor growth dynamics mathematical model, an instance of the particle swarm optimization method was implemented to speed up the search process in the multi-dimensional parameter space to find optimal parameter values that fit experimental data from mice cancel cells. The fitness function, which measures the difference between calculated results and experimental data, was minimized in the numerical simulation process. The results and search efficiency of the particle swarm optimization method were compared to those from other evolutional methods such as genetic algorithms.

Photoacoustic imaging to assess pixel-based sO2 distributions in experimental prostate tumors

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Bendinger, Alina L.; Glowa, Christin; Peter, Jörg; Karger, Christian P.

2018-03-01

A protocol for photoacoustic imaging (PAI) has been developed to assess pixel-based oxygen saturation (sO2) distributions of experimental tumor models. The protocol was applied to evaluate the dependence of PAI results on measurement settings, reproducibility of PAI, and for the characterization of the oxygenation status of experimental prostate tumor sublines (Dunning R3327-H, -HI, -AT1) implanted subcutaneously in male Copenhagen rats. The three-dimensional (3-D) PA data employing two wavelengths were used to estimate sO2 distributions. If the PA signal was sufficiently strong, the distributions were independent from signal gain, threshold, and positioning of animals. Reproducibility of sO2 distributions with respect to shape and median values was demonstrated over several days. The three tumor sublines were characterized by the shapes of their sO2 distributions and their temporal response after external changes of the oxygen supply (100% O2 or air breathing and clamping of tumor-supplying artery). The established protocol showed to be suitable for detecting temporal changes in tumor oxygenation as well as differences in oxygenation between tumor sublines. PA results were in accordance with histology for hypoxia, perfusion, and vasculature. The presented protocol for the assessment of pixel-based sO2 distributions provides more detailed information as compared to conventional region-of-interest-based analysis of PAI, especially with respect to the detection of temporal changes and tumor heterogeneity.

Photoacoustic imaging to assess pixel-based sO2 distributions in experimental prostate tumors.

Science.gov (United States)

Bendinger, Alina L; Glowa, Christin; Peter, Jörg; Karger, Christian P

2018-03-01

A protocol for photoacoustic imaging (PAI) has been developed to assess pixel-based oxygen saturation (sO2) distributions of experimental tumor models. The protocol was applied to evaluate the dependence of PAI results on measurement settings, reproducibility of PAI, and for the characterization of the oxygenation status of experimental prostate tumor sublines (Dunning R3327-H, -HI, -AT1) implanted subcutaneously in male Copenhagen rats. The three-dimensional (3-D) PA data employing two wavelengths were used to estimate sO2 distributions. If the PA signal was sufficiently strong, the distributions were independent from signal gain, threshold, and positioning of animals. Reproducibility of sO2 distributions with respect to shape and median values was demonstrated over several days. The three tumor sublines were characterized by the shapes of their sO2 distributions and their temporal response after external changes of the oxygen supply (100% O2 or air breathing and clamping of tumor-supplying artery). The established protocol showed to be suitable for detecting temporal changes in tumor oxygenation as well as differences in oxygenation between tumor sublines. PA results were in accordance with histology for hypoxia, perfusion, and vasculature. The presented protocol for the assessment of pixel-based sO2 distributions provides more detailed information as compared to conventional region-of-interest-based analysis of PAI, especially with respect to the detection of temporal changes and tumor heterogeneity. (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

THE EFFECT OF ASCORBIC ACID ON PATHOHISTOLOGICAL TUMOR CHARACTERISTICS AND PHENOTYPE CHARACTERISTICS OF LYMPHOCYTES DURING THE DEVELOPMENT OF EXPERIMENTAL MAMMARY CARCINOMA IN MICE

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Voja Pavlovic

2005-04-01

Full Text Available TIn our previous study we demonstrated that high doses of ascorbic acid prolonged the survival of mice with experimental mammary carcinoma. In this work we studied, ussing the same model, pathohistological characteristics of the tumor and phenotypic changes of lymphocyte subsets in the spleen. Experiments were performed on CBA/H mice. The growh of experimental tumor was induced by injection of mammary adenocarcinoma cells intramuscularly at the femoral region of mice. The animals were divided into control group and three experimental groups (I, II and III. Mice from experimental groups were treated peroraly with 10, 100 and 1000 mg/kg body mass (b.m. of ascorbic acid, respectively, whereas control mice received physiological saline. Mice were sacrified after 7, 14 and 21 days from the beginning of the experiment. Total tumor mass and its pathohistological characteristics, spleen mass and cellularity as well as relative and total numbers of T cells, B cells and T cell subsets (CD4+ and CD8+ in the spleen, were analyzed. High doses of ascorbic acid decreased tumor mass, stimulated proliferation of fibroblasts and formation of capsula arround the tumor, induced tumor necrosis and increased the number of tumor infiltrating lymphocytes. Changes of lymphocyte subsets and their numbers varied depending on the applied dose of ascorbic acid and the time elapsed following tumor induction. The most prominent changes, manifested by an increase in the number of CD4+ T cells were observed on the 14th day in II experimental group. Our results suggest that the beneficial effect of ascorbic acid on experimental tumorogenesis in our model was the consequence of its influence on the tumor and on the immune system.

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...

Augmented reality in a tumor resection model.

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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.

Xenograft transplantation of human malignant astrocytoma cells into immunodeficient rats: an experimental model of glioblastoma.

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Miura, Flávio Key; Alves, Maria Jose Ferreira; Rocha, Mussya Cisotto; da Silva, Roseli; Oba-Shinjo, Sueli Mieko; Marie, Suely Kazue Nagahashi

2010-03-01

Astrocytic gliomas are the most common intracranial central nervous system neoplasias, accounting for about 60% of all primary central nervous system tumors. Despite advances in the treatment of gliomas, no effective therapeutic approach is yet available; hence, the search for a more realistic model to generate more effective therapies is essential. To develop an experimental malignant astrocytoma model with the characteristics of the human tumor. Primary cells from subcutaneous xenograft tumors produced with malignant astrocytoma U87MG cells were inoculated intracerebrally by stereotaxis into immunosuppressed (athymic) Rowett rats. All four injected animals developed non-infiltrative tumors, although other glioblastoma characteristics, such as necrosis, pseudopalisading cells and intense mitotic activity, were observed. A malignant astrocytoma intracerebral xenograft model with poorly invasive behavior was achieved in athymic Rowett rats. Tumor invasiveness in an experimental animal model may depend on a combination of several factors, including the cell line used to induce tumor formation, the rat strains and the status of the animal's immune system.

The fibrinolytic system facilitates tumor cell migration across the blood-brain barrier in experimental melanoma brain metastasis

International Nuclear Information System (INIS)

Perides, George; Zhuge, Yuzheng; Lin, Tina; Stins, Monique F; Bronson, Roderick T; Wu, Julian K

2006-01-01

Patients with metastatic tumors to the brain have a very poor prognosis. Increased metastatic potential has been associated with the fibrinolytic system. We investigated the role of the fibrinolytic enzyme plasmin in tumor cell migration across brain endothelial cells and growth of brain metastases in an experimental metastatic melanoma model. Metastatic tumors to the brain were established by direct injection into the striatum or by intracarotid injection of B16F10 mouse melanoma cells in C57Bl mice. The role of plasminogen in the ability of human melanoma cells to cross a human blood-brain barrier model was studied on a transwell system. Wild type mice treated with the plasmin inhibitor epsilon-aminocaproic acid (EACA) and plg -/- mice developed smaller tumors and survived longer than untreated wild type mice. Tumors metastasized to the brain of wild type mice treated with EACA and plg -/- less efficiently than in untreated wild type mice. No difference was observed in the tumor growth in any of the three groups of mice. Human melanoma cells were able to cross the human blood-brain barrier model in a plasmin dependent manner. Plasmin facilitates the development of tumor metastasis to the brain. Inhibition of the fibrinolytic system could be considered as means to prevent tumor metastasis to the brain

Accessing key steps of human tumor progression in vivo by using an avian embryo model

Science.gov (United States)

Hagedorn, Martin; Javerzat, Sophie; Gilges, Delphine; Meyre, Aurélie; de Lafarge, Benjamin; Eichmann, Anne; Bikfalvi, Andreas

2005-02-01

Experimental in vivo tumor models are essential for comprehending the dynamic process of human cancer progression, identifying therapeutic targets, and evaluating antitumor drugs. However, current rodent models are limited by high costs, long experimental duration, variability, restricted accessibility to the tumor, and major ethical concerns. To avoid these shortcomings, we investigated whether tumor growth on the chick chorio-allantoic membrane after human glioblastoma cell grafting would replicate characteristics of the human disease. Avascular tumors consistently formed within 2 days, then progressed through vascular endothelial growth factor receptor 2-dependent angiogenesis, associated with hemorrhage, necrosis, and peritumoral edema. Blocking of vascular endothelial growth factor receptor 2 and platelet-derived growth factor receptor signaling pathways by using small-molecule receptor tyrosine kinase inhibitors abrogated tumor development. Gene regulation during the angiogenic switch was analyzed by oligonucleotide microarrays. Defined sample selection for gene profiling permitted identification of regulated genes whose functions are associated mainly with tumor vascularization and growth. Furthermore, expression of known tumor progression genes identified in the screen (IL-6 and cysteine-rich angiogenic inducer 61) as well as potential regulators (lumican and F-box-only 6) follow similar patterns in patient glioma. The model reliably simulates key features of human glioma growth in a few days and thus could considerably increase the speed and efficacy of research on human tumor progression and preclinical drug screening. angiogenesis | animal model alternatives | glioblastoma

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

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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

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

Radiosensitizing effect of nitric oxide in tumor cells and experimental tumors irradiated with gamma rays and proton beams

International Nuclear Information System (INIS)

Policastro, Lucia L.; Duran, Hebe; Molinari, Beatriz L.; Somacal, Hector R.; Valda, Alejandro A.

2003-01-01

Nitric oxide (NO) has been reported to be a radiosensitizer of mammalian cells under hypoxic conditions. In a previous study, we demonstrated an enhancement in radiation response induced by NO in mouse tumor cells under aerobic conditions, with an increasing effect as a function of malignancy. The aim of the present study was to evaluate the effect of NO in tumor cells and in experimental tumors irradiated with γ rays and proton beams. Irradiations were performed with a 137 Cs γ source and with proton beams generated by the TANDAR accelerator. Tumor cells were treated with the NO donor DETA-NO and the sensitizer enhancement ratio (SER) was calculated using the α parameter of the survival curve fitted to the linear-quadratic model. Tumor cells irradiated with protons were radio sensitized by DETA-NO only in the more malignant cells irradiated with low LET protons (2.69±0.08 keV/μm). For higher LET protons there were no radiosensitizing effect. For human tumor cells pre-treated with DETA-NO and irradiated with γ rays, a significantly greater effect was demonstrated in the malignant cells (MCF-7) as compared with the near normal cells (HBL-100). Moreover, a significant decrease in tumor growth was demonstrated in mice pre-treated with the NO donor spermine and irradiated with γ rays and low LET protons as compared with mice irradiated without pre-treatment with the NO donor. In conclusion, we demonstrated a differential effect of NO as a radiosensitizer of malignant cells, both with γ rays and low LET protons. This selectivity, coupled to the in vivo inhibition of tumor growth, is of great interest for the potential use of NO releasing agents in radiotherapy. (author)

Small Animal [18F]FDG PET Imaging for Tumor Model Study

International Nuclear Information System (INIS)

Woo, Sang Keun; Kim, Kyeong Min; Cheon, Gi Jeong

2008-01-01

PET allows non-invasive, quantitative and repetitive imaging of biological function in living animals. Small animal PET imaging with [ 18 F]FDG has been successfully applied to investigation of metabolism, receptor, ligand interactions, gene expression, adoptive cell therapy and somatic gene therapy. Experimental condition of animal handling impacts on the biodistribution of [ 18 F]FDG in small animal study. The small animal PET and CT images were registered using the hardware fiducial markers and small animal contour point. Tumor imaging in small animal with small animal [ 18 F]FDG PET should be considered fasting, warming, and isoflurane anesthesia level. Registered imaging with small animal PET and CT image could be useful for the detection of tumor. Small animal experimental condition of animal handling and registration method will be of most importance for small lesion detection of metastases tumor model

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)

Applications of Magnetic Resonance in Model Systems: Tumor Biology and Physiology

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Robert J. Gillies

2000-01-01

Full Text Available A solid tumor presents a unique challenge as a system in which the dynamics of the relationship between vascularization, the physiological environment and metabolism are continually changing with growth and following treatment. Magnetic resonance imaging (MRI and magnetic resonance spectroscopy (MRS studies have demonstrated quantifiable linkages between the physiological environment, angiogenesis, vascularization and metabolism of tumors. The dynamics between these parameters continually change with tumor aggressiveness, tumor growth and during therapy and each of these can be monitored longitudinally, quantitatively and non-invasively with MRI and MRS. An important aspect of MRI and MRS studies is that techniques and findings are easily translated between systems. Hence, pre-clinical studies using cultured cells or experimental animals have a high connectivity to potential clinical utility. In the following review, leaders in the field of MR studies of basic tumor physiology using pre-clinical models have contributed individual sections according to their expertise and outlook. The following review is a cogent and timely overview of the current capabilities and state-of-the-art of MRI and MRS as applied to experimental cancers. A companion review deals with the application of MR methods to anticancer therapy.

SU-E-T-751: Three-Component Kinetic Model of Tumor Growth and Radiation Response for Stereotactic Radiosurgery

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Watanabe, Y; Dahlman, E; Leder, K; Hui, S [University of Minnesota, Minneapolis, MN (United States)

2015-06-15

Purpose: To develop and study a kinetic model of tumor growth and its response to stereotactic radiosurgery (SRS) by assuming that the cells in irradiated tumor volume were made of three types. Methods: A set of ordinary differential equations (ODEs) were derived for three types of cells and a tumor growth rate. It is assumed that the cells were composed of actively proliferating cells, lethally damaged-dividing cells, and non-dividing cells. We modeled the tumor volume growth with a time-dependent growth rate to simulate the saturation of growth. After SRS, the proliferating cells were permanently damaged and converted to the lethally damaged cells. The amount of damaged cells were estimated by the LQ-model. The damaged cells gradually stopped dividing/proliferating and died with a constant rate. The dead cells were cleared from their original location with a constant rate. The total tumor volume was the sum of the three components. The ODEs were numerically solved with appropriate initial conditions for a given dosage. The proposed model was used to model an animal experiment, for which the temporal change of a rhabdomyosarcoma tumor volume grown in a rat was measured with time resolution sufficient to test the model. Results: To fit the model to the experimental data, the following characteristics were needed with the model parameters. The α-value in the LQ-model was smaller than the commonly used value; furthermore, it decreased with increasing dose. At the same time, the tumor growth rate after SRS had to increase. Conclusions: The new 3-component model of tumor could simulate the experimental data very well. The current study suggested that the radiation sensitivity and the growth rate of the proliferating tumor cells may change after irradiation and it depended on the dosage used for SRS. These preliminary observations must be confirmed by future animal experiments.

Tumor cell culture on collagen–chitosan scaffolds as three-dimensional tumor model: A suitable model for tumor studies

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Aziz Mahmoudzadeh

2016-07-01

Full Text Available Tumor cells naturally live in three-dimensional (3D microenvironments, while common laboratory tests and evaluations are done in two-dimensional (2D plates. This study examined the impact of cultured 4T1 cancer cells in a 3D collagen–chitosan scaffold compared with 2D plate cultures. Collagen–chitosan scaffolds were provided and passed confirmatory tests. 4T1 tumor cells were cultured on scaffolds and then tumor cells growth rate, resistance to X-ray radiation, and cyclophosphamide as a chemotherapy drug were analyzed. Furthermore, 4T1 cells were extracted from the scaffold model and were injected into the mice. Tumor growth rate, survival rate, and systemic immune responses were evaluated. Our results showed that 4T1 cells infiltrated the scaffolds pores and constructed a 3D microenvironment. Furthermore, 3D cultured tumor cells showed a slower proliferation rate, increased levels of survival to the X-ray irradiation, and enhanced resistance to chemotherapy drugs in comparison with 2D plate cultures. Transfer of extracted cells to the mice caused enhanced tumor volume and decreased life span. This study indicated that collagen–chitosan nanoscaffolds provide a suitable model of tumor that would be appropriate for tumor studies.

Tumor cell culture on collagen-chitosan scaffolds as three-dimensional tumor model: A suitable model for tumor studies.

Science.gov (United States)

Mahmoudzadeh, Aziz; Mohammadpour, Hemn

2016-07-01

Tumor cells naturally live in three-dimensional (3D) microenvironments, while common laboratory tests and evaluations are done in two-dimensional (2D) plates. This study examined the impact of cultured 4T1 cancer cells in a 3D collagen-chitosan scaffold compared with 2D plate cultures. Collagen-chitosan scaffolds were provided and passed confirmatory tests. 4T1 tumor cells were cultured on scaffolds and then tumor cells growth rate, resistance to X-ray radiation, and cyclophosphamide as a chemotherapy drug were analyzed. Furthermore, 4T1 cells were extracted from the scaffold model and were injected into the mice. Tumor growth rate, survival rate, and systemic immune responses were evaluated. Our results showed that 4T1 cells infiltrated the scaffolds pores and constructed a 3D microenvironment. Furthermore, 3D cultured tumor cells showed a slower proliferation rate, increased levels of survival to the X-ray irradiation, and enhanced resistance to chemotherapy drugs in comparison with 2D plate cultures. Transfer of extracted cells to the mice caused enhanced tumor volume and decreased life span. This study indicated that collagen-chitosan nanoscaffolds provide a suitable model of tumor that would be appropriate for tumor studies. Copyright © 2016. Published by Elsevier B.V.

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

Glioma Surgical Aspirate: A Viable Source of Tumor Tissue for Experimental Research

International Nuclear Information System (INIS)

Day, Bryan W.; Stringer, Brett W.; Wilson, John; Jeffree, Rosalind L.; Jamieson, Paul R.

2013-01-01

Brain cancer research has been hampered by a paucity of viable clinical tissue of sufficient quality and quantity for experimental research. This has driven researchers to rely heavily on long term cultured cells which no longer represent the cancers from which they were derived. Resection of brain tumors, particularly at the interface between normal and tumorigenic tissue, can be carried out using an ultrasonic surgical aspirator (CUSA) that deposits liquid (blood and irrigation fluid) and resected tissue into a sterile bottle for disposal. To determine the utility of CUSA-derived glioma tissue for experimental research, we collected 48 CUSA specimen bottles from glioma patients and analyzed both the solid tissue fragments and dissociated tumor cells suspended in the liquid waste fraction. We investigated if these fractions would be useful for analyzing tumor heterogeneity, using IHC and multi-parameter flow cytometry; we also assessed culture generation and orthotopic xenograft potential. Both cell sources proved to be an abundant, highly viable source of live tumor cells for cytometric analysis, animal studies and in-vitro studies. Our findings demonstrate that CUSA tissue represents an abundant viable source to conduct experimental research and to carry out diagnostic analyses by flow cytometry or other molecular diagnostic procedures

White Adipose Tissue Cells Are Recruited by Experimental Tumors and Promote Cancer Progression in Mouse Models

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Zhang, Yan; Daquinag, Alexes; Traktuev, Dmitry O.; Amaya-Manzanares, Felipe; Simmons, Paul J.; March, Keith L.; Pasqualini, Renata; Arap, Wadih; Kolonin, Mikhail G.

2010-01-01

The connection between obesity and accelerated cancer progression has been established, but the mediating mechanisms are not well understood. We have shown that stromal cells from white adipose tissue (WAT) cooperate with the endothelium to promote blood vessel formation through the secretion of soluble trophic factors. Here, we hypothesize that WAT directly mediates cancer progression by serving as a source of cells that migrate to tumors and promote neovascularization. To test this hypothesis, we have evaluated the recruitment of WAT-derived cells by tumors and the effect of their engraftment on tumor growth by integrating a transgenic mouse strain engineered for expansion of traceable cells with established allograft and xenograft cancer models. Our studies show that entry of adipose stromal and endothelial cells into systemic circulation leads to their homing to and engraftment into tumor stroma and vasculature, respectively. We show that recruitment of adipose stromal cells by tumors is sufficient to promote tumor growth. Finally, we show that migration of stromal and vascular progenitor cells from WAT grafts to tumors is also associated with acceleration of cancer progression. These results provide a biological insight for the clinical association between obesity and cancer, thus outlining potential avenues for preventive and therapeutic strategies. PMID:19491274

A fundamental study of dynamic CT for hemodynamics in experimental hepatic tumors

International Nuclear Information System (INIS)

Yamakawa, Fumiko

1991-01-01

Dynamic CT was performed using iodamide meglumine (2 ml/kg) to investigate hemodynamics in experimental hepatic tumors, tumor margins and in normal hepatic tissue as well in rabbits with VX 2 -induced hepatic tumors. Peak time (PT) and first moment (M1) were calculated from a time density curve prepared by eight consecutive 3-second scans over a period of 55 seconds. PT and M1 in tumors were significantly shorter than those in tumor margins and normal tissue, but were not influenced by tumor size. PT and M1 in tumor margins and normal tissue became longer with enlargement of the tumor. Ligation of the hepatic artery caused (1) no change in PT or M1 in normal tissue and tumor margins and (2) difficulty in measuring PT and M1 in tumors. Ligation of the portal vein caused (1) difficulty in measuring PT and M1 in normal tissue and tumor margins and (2) no change in PT or M1 in tumors. Pathological studies of specimens taken from each region of interest (ROI) showed that hemodynamics in the tumors reflected tumor-specific vascular structures. (author)

Perfusion kinetics in human brain tumor with DCE-MRI derived model and CFD analysis.

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Bhandari, A; Bansal, A; Singh, A; Sinha, N

2017-07-05

Cancer is one of the leading causes of death all over the world. Among the strategies that are used for cancer treatment, the effectiveness of chemotherapy is often hindered by factors such as irregular and non-uniform uptake of drugs inside tumor. Thus, accurate prediction of drug transport and deposition inside tumor is crucial for increasing the effectiveness of chemotherapeutic treatment. In this study, a computational model of human brain tumor is developed that incorporates dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI) data into a voxelized porous media model. The model takes into account realistic transport and perfusion kinetics parameters together with realistic heterogeneous tumor vasculature and accurate arterial input function (AIF), which makes it patient specific. The computational results for interstitial fluid pressure (IFP), interstitial fluid velocity (IFV) and tracer concentration show good agreement with the experimental results. The computational model can be extended further for predicting the deposition of chemotherapeutic drugs in tumor environment as well as selection of the best chemotherapeutic drug for a specific patient. Copyright © 2017 Elsevier Ltd. All rights reserved.

A mechanistic compartmental model for total antibody uptake in tumors.

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Thurber, Greg M; Dane Wittrup, K

2012-12-07

Antibodies are under development to treat a variety of cancers, such as lymphomas, colon, and breast cancer. A major limitation to greater efficacy for this class of drugs is poor distribution in vivo. Localization of antibodies occurs slowly, often in insufficient therapeutic amounts, and distributes heterogeneously throughout the tumor. While the microdistribution around individual vessels is important for many therapies, the total amount of antibody localized in the tumor is paramount for many applications such as imaging, determining the therapeutic index with antibody drug conjugates, and dosing in radioimmunotherapy. With imaging and pretargeted therapeutic strategies, the time course of uptake is critical in determining when to take an image or deliver a secondary reagent. We present here a simple mechanistic model of antibody uptake and retention that captures the major rates that determine the time course of antibody concentration within a tumor including dose, affinity, plasma clearance, target expression, internalization, permeability, and vascularization. Since many of the parameters are known or can be estimated in vitro, this model can approximate the time course of antibody concentration in tumors to aid in experimental design, data interpretation, and strategies to improve localization. Copyright © 2012 Elsevier Ltd. All rights reserved.

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

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

2015-01-01

found to be significantly more important for reoxygenation than angiogenesis or decreased oxygen consumption due to an increased fraction of dead cells. In the studied HNSSC-case, the TCD50 values (dose at 50% TCP) decreased from 71.0 Gy under hypoxic to 53.6 Gy under the oxic condition. The results obtained with the developed multiscale model are in accordance with expectations based on radiobiological principles and clinical experience. As the model is voxel-based, radiological imaging methods may help to provide the required 3D-characterization of the tumor prior to irradiation. For clinical application, the model has to be further validated with experimental and clinical data. If this is achieved, the model may be used to optimize fractionation schedules and dose distributions for the treatment of hypoxic tumors.

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

International Nuclear Information System (INIS)

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

2015-01-01

model, tumor shrinkage was found to be significantly more important for reoxygenation than angiogenesis or decreased oxygen consumption due to an increased fraction of dead cells. In the studied HNSSC-case, the TCD 50 values (dose at 50% TCP) decreased from 71.0 Gy under hypoxic to 53.6 Gy under the oxic condition. Conclusions: The results obtained with the developed multiscale model are in accordance with expectations based on radiobiological principles and clinical experience. As the model is voxel-based, radiological imaging methods may help to provide the required 3D-characterization of the tumor prior to irradiation. For clinical application, the model has to be further validated with experimental and clinical data. If this is achieved, the model may be used to optimize fractionation schedules and dose distributions for the treatment of hypoxic tumors

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.

A comparison of scintigraphy with tumor-seeking radiopharmaceuticals to detect an experimental bone tumors in the rabbits

International Nuclear Information System (INIS)

Otsuka, Nobuaki; Sone, Teruki; Fukunaga, Masao

2003-01-01

A comparative study on the accumulation of 99m Tc-phosphorous compound, 99m Tc-hexakis-2-methoxy isobutyl-isonitrile (MIBI), and 99m Tc-tetrofosmin (TF) in the experimental bone tumors using the VX-2 cell was performed. In the group of the femoral metastatic bone tumor, 99m Tc-MIBI showed no accumulation in the femur at 12 days after the transplantation despite the presence of a bone marrow tumor. In the group of the iliac metastatic bone tumor, a bone scintigraphy showed decreased accumulation in the ileum at 16 days, but hot lesions were observed in same sites at 18 days after the transplantation on 99m Tc-MIBI and 99m Tc-TF scintigrams. The tumor to soft tissue accumulation ratio was higher for 99m Tc-MIBI (3.03±1.03) than for 99m Tc-TF (2.55±0.80) (P 99m Tc-MIBI is less satisfactory for the early diagnosis of tumors than bone scintigraphy, and a combined study with both 99m Tc-phosphorous compounds and 99m Tc-MIBI is useful for the evaluation and diagnosis of lesions. (author)

Hyperglycemia and ultrasound in radiotherapy of experimental tumors (a preliminary paper)

International Nuclear Information System (INIS)

Muratkhodzhaev, N.K.; Prus, E.S.; Zakirkhodzhaev, U.D.; Kutlimuratov, A.B.

1984-01-01

Experimental studies have shown that all the types of effects, as compared with the control, result in inhibition of the tumor growth; X-ray therapy decelerates the tumor growth, but its combination with hyperglycemia produced a more vivid effect. Inhibition of the tumor growth, as compared with that in the control group, was observed under a combined effect of hyperglycemia with ultrasound, though it was noticeably weaker than under other effects. Application of a complex effect including hyperglycemia, ultrasound, X-ray therapy turned to be most effective, the succession of their application playing an important role for the antitumoral effect of the used factors

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

The Mouse Tumor Biology Database: A Comprehensive Resource for Mouse Models of Human Cancer.

Science.gov (United States)

Krupke, Debra M; Begley, Dale A; Sundberg, John P; Richardson, Joel E; Neuhauser, Steven B; Bult, Carol J

2017-11-01

Research using laboratory mice has led to fundamental insights into the molecular genetic processes that govern cancer initiation, progression, and treatment response. Although thousands of scientific articles have been published about mouse models of human cancer, collating information and data for a specific model is hampered by the fact that many authors do not adhere to existing annotation standards when describing models. The interpretation of experimental results in mouse models can also be confounded when researchers do not factor in the effect of genetic background on tumor biology. The Mouse Tumor Biology (MTB) database is an expertly curated, comprehensive compendium of mouse models of human cancer. Through the enforcement of nomenclature and related annotation standards, MTB supports aggregation of data about a cancer model from diverse sources and assessment of how genetic background of a mouse strain influences the biological properties of a specific tumor type and model utility. Cancer Res; 77(21); e67-70. ©2017 AACR . ©2017 American Association for Cancer Research.

Use of 99mTc-HYNIC-βAla-Bombesina(7-14) peptide for the identification of prostate tumor, LNCaP line, in an experimental model

International Nuclear Information System (INIS)

Fuscaldi, Leonardo Lima

2012-01-01

Prostate cancer is one of the most prevalent tumors in men, showing high mortality rates. Current diagnostic methods are not able to identify early prostate carcinoma, often resulting in a late diagnosis with established metastasis. Thus, there is by the scientific community an incessant search for diagnostic methods for early assessment of prostate cancer, facilitating the treatment and increasing the chances of cure. In this context, nuclear medicine provides a diagnostic method which can detect tumors at an early stage, because it is based on biochemical and physiological changes of the tissue, such as overexpression of gastrin releasing peptide receptors (GRPr's) by prostate cancer cells. Bombesin, a tetradecapeptide isolated from the frog Bombina bombina, has a high affinity for the GRPr's, since it is analogous to gastrin releasing peptide. Therefore, this study aims to prepare the complex 99m Tc-HYNIC-βAla-Bombesina (7-14) and use it for the identification of prostate tumor, LNCaP line, in an experimental model. For in vitro assays, aliquots of 0.026 MBq of the radiopeptide were incubated with 2x10 6 LNCaP cells in a water bath at 37 deg C, for 1 and 4 hours, with and without prior addition of cold peptide (n=3). Prostate tumors were induced into the upper right flank of male BALB/c nude mice by subcutaneous injection of 5x106 LNCaP cells resuspended in 150 μL of Matrigel:RPMI-1640 medium (1:1). Biodistribution profile (n=5) and scintigraphic images (n=3) were obtained at 1 and 4 hours after intravenous injection of 7.4 MBq of 99m Tc-HYNIC-βAla-Bombesina (7-14) . To assess this, healthy male BALB/c mice and tumor-bearing male BALB/c nude mice with 15, 20 and 25 days of tumor development were used. In vitro study results showed that the fraction of the radiopeptide which bound to LNCaP cells was 2.08 +- 0.30% (1 hour) and 2.44 +- 0.18% (4 hours). From the percentage which was bound, the internalized fractions were 25.64 +- 3.14% (1 hour) and 25.27 +- 2

A non-equilibrium thermodynamic model for tumor extracellular matrix with enzymatic degradation

Science.gov (United States)

Xue, Shi-Lei; Li, Bo; Feng, Xi-Qiao; Gao, Huajian

2017-07-01

The extracellular matrix (ECM) of a solid tumor not only affords scaffolding to support tumor architecture and integrity but also plays an essential role in tumor growth, invasion, metastasis, and therapeutics. In this paper, a non-equilibrium thermodynamic theory is established to study the chemo-mechanical behaviors of tumor ECM, which is modeled as a poroelastic polyelectrolyte consisting of a collagen network and proteoglycans. By using the principle of maximum energy dissipation rate, we deduce a set of governing equations for drug transport and mechanosensitive enzymatic degradation in ECM. The results reveal that osmosis is primarily responsible for the compression resistance of ECM. It is suggested that a well-designed ECM degradation can effectively modify the tumor microenvironment for improved efficiency of cancer therapy. The theoretical predictions show a good agreement with relevant experimental observations. This study aimed to deepen our understanding of tumor ECM may be conducive to novel anticancer strategies.

A new ODE tumor growth modeling based on tumor population dynamics

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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.

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

Modeling the tumor extracellular matrix: Tissue engineering tools repurposed towards new frontiers in cancer biology.

Science.gov (United States)

Gill, Bartley J; West, Jennifer L

2014-06-27

Cancer progression is mediated by complex epigenetic, protein and structural influences. Critical among them are the biochemical, mechanical and architectural properties of the extracellular matrix (ECM). In recognition of the ECM's important role, cancer biologists have repurposed matrix mimetic culture systems first widely used by tissue engineers as new tools for in vitro study of tumor models. In this review we discuss the pathological changes in tumor ECM, the limitations of 2D culture on both traditional and polyacrylamide hydrogel surfaces in modeling these characteristics and advances in both naturally derived and synthetic scaffolds to facilitate more complex and controllable 3D cancer cell culture. Studies using naturally derived matrix materials like Matrigel and collagen have produced significant findings related to tumor morphogenesis and matrix invasion in a 3D environment and the mechanotransductive signaling that mediates key tumor-matrix interaction. However, lack of precise experimental control over important matrix factors in these matrices have increasingly led investigators to synthetic and semi-synthetic scaffolds that offer the engineering of specific ECM cues and the potential for more advanced experimental manipulations. Synthetic scaffolds composed of poly(ethylene glycol) (PEG), for example, facilitate highly biocompatible 3D culture, modular bioactive features like cell-mediated matrix degradation and complete independent control over matrix bioactivity and mechanics. Future work in PEG or similar reductionist synthetic matrix systems should enable the study of increasingly complex and dynamic tumor-ECM relationships in the hopes that accurate modeling of these relationships may reveal new cancer therapeutics targeting tumor progression and metastasis. © 2013 Published by Elsevier Ltd.

Experimental tumor therapy

International Nuclear Information System (INIS)

1982-06-01

This is a report on the work of the joint research group of the Institute of Radiation Biology (Strahlenbiologisches Institut) of the university of Munich and the Department of Radiation Biology of the Society for Radiation and Environmental Research (Gesellschaft fuer Strahlen- u. Umweltforschung - GSF -) at Neuherberg. The presented results are not in all cases definitely confirmed or have, in part, merely provisional character. It is the target of the joint research to investigate problems of cancer therapy of practical impact in model form and to develop recommendations in discussions with therapists. Thus, the aim is not so much to examine mechanisms of action of certain radiations in detail but to look for the general rules they are governed by and to analyze the quantitative aspects of cancer therapy. To achieve this, a great variety of test models must be at hand. Numerous cell cultivies and tumors of mice resp. rats are therefore used. The acute reactions to irradiation are examined on the skin, the small intestine crypts, the bone marrow and spleen colonies of mice and the chronic reactions are tested on the colon and heart of rats and on the vascular connective tissue and kidneys of mice. (orig./MG) [de

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.

Tumor immunology

International Nuclear Information System (INIS)

Otter, W. den

1987-01-01

Tumor immunology, the use of immunological techniques for tumor diagnosis and approaches to immunotherapy of cancer are topics covered in this multi-author volume. Part A, 'Tumor Immunology', deals with present views on tumor-associated antigens, the initiation of immune reactions of tumor cells, effector cell killing, tumor cells and suppression of antitumor immunity, and one chapter dealing with the application of mathematical models in tumor immunology. Part B, 'Tumor Diagnosis and Imaging', concerns the use of markers to locate the tumor in vivo, for the histological diagnosis, and for the monitoring of tumor growth. In Part C, 'Immunotherapy', various experimental approaches to immunotherapy are described, such as the use of monoclonal antibodies to target drugs, the use of interleukin-2 and the use of drugs inhibiting suppression. In the final section, the evaluation, a pathologist and a clinician evaluate the possibilities and limitations of tumor immunology and the extent to which it is useful for diagnosis and therapy. refs.; figs.; tabs

Dynamics of melanoma tumor therapy with vesicular stomatitis virus: explaining the variability in outcomes using mathematical modeling.

Science.gov (United States)

Rommelfanger, D M; Offord, C P; Dev, J; Bajzer, Z; Vile, R G; Dingli, D

2012-05-01

Tumor selective, replication competent viruses are being tested for cancer gene therapy. This approach introduces a new therapeutic paradigm due to potential replication of the therapeutic agent and induction of a tumor-specific immune response. However, the experimental outcomes are quite variable, even when studies utilize highly inbred strains of mice and the same cell line and virus. Recognizing that virotherapy is an exercise in population dynamics, we utilize mathematical modeling to understand the variable outcomes observed when B16ova malignant melanoma tumors are treated with vesicular stomatitis virus in syngeneic, fully immunocompetent mice. We show how variability in the initial tumor size and the actual amount of virus delivered to the tumor have critical roles on the outcome of therapy. Virotherapy works best when tumors are small, and a robust innate immune response can lead to superior tumor control. Strategies that reduce tumor burden without suppressing the immune response and methods that maximize the amount of virus delivered to the tumor should optimize tumor control in this model system.

Mathematical modeling of tumor-induced immunosuppression by myeloid-derived suppressor cells: Implications for therapeutic targeting strategies.

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Shariatpanahi, Seyed Peyman; Shariatpanahi, Seyed Pooya; Madjidzadeh, Keivan; Hassan, Moustapha; Abedi-Valugerdi, Manuchehr

2018-04-07

Myeloid-derived suppressor cells (MDSCs) belong to immature myeloid cells that are generated and accumulated during the tumor development. MDSCs strongly suppress the anti-tumor immunity and provide conditions for tumor progression and metastasis. In this study, we present a mathematical model based on ordinary differential equations (ODE) to describe tumor-induced immunosuppression caused by MDSCs. The model consists of four equations and incorporates tumor cells, cytotoxic T cells (CTLs), natural killer (NK) cells and MDSCs. We also provide simulation models that evaluate or predict the effects of anti-MDSC drugs (e.g., l-arginine and 5-Fluorouracil (5-FU)) on the tumor growth and the restoration of anti-tumor immunity. The simulated results obtained using our model were in good agreement with the corresponding experimental findings on the expansion of splenic MDSCs, immunosuppressive effects of these cells at the tumor site and effectiveness of l-arginine and 5-FU on the re-establishment of antitumor immunity. Regarding this latter issue, our predictive simulation results demonstrated that intermittent therapy with low-dose 5-FU alone could eradicate the tumors irrespective of their origins and types. Furthermore, at the time of tumor eradication, the number of CTLs prevailed over that of cancer cells and the number of splenic MDSCs returned to the normal levels. Finally, our predictive simulation results also showed that the addition of l-arginine supplementation to the intermittent 5-FU therapy reduced the time of the tumor eradication and the number of iterations for 5-FU treatment. Thus, the present mathematical model provides important implications for designing new therapeutic strategies that aim to restore antitumor immunity by targeting MDSCs. Copyright © 2018 Elsevier Ltd. All rights reserved.

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

Experimental tumor growth of canine osteosarcoma cell line on chick embryo chorioallantoic membrane (in vivo studies).

Science.gov (United States)

Walewska, Magdalena; Dolka, Izabella; Małek, Anna; Wojtalewicz, Anna; Wojtkowska, Agata; Żbikowski, Artur; Lechowski, Roman; Zabielska-Koczywąs, Katarzyna

2017-05-12

The chick embryo chorioallantoic membrane (CAM) model is extensively used in human medicine in preclinical oncological studies. The CAM model has several advantages: low cost, simple experimental approach, time saving and following "3R principles". Research has shown that the human osteosarcoma cell lines U2OS, MMNG-HOS, and SAOS can form tumors on the CAM. In veterinary medicine, this has been described only for feline fibrosarcomas, feline mammary carcinomas and canine osteosarcomas. However, in case of canine osteosarcomas, it has been shown that only non-adherent osteosarcoma stem cells isolated from KTOSA5 and CSKOS cell lines have the ability to form microtumors on the CAM after an incubation period of 5 days, in contrast to adherent KTOSA5 and CSKOS cells. In the presented study, we have proven that the commercial adherent canine osteosarcoma cell line (D-17) can form vascularized tumors on the CAM after the incubation period of 10 days.

Mathematical Modeling of Cellular Cross-Talk Between Endothelial and Tumor Cells Highlights Counterintuitive Effects of VEGF-Targeted Therapies.

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Jain, Harsh; Jackson, Trachette

2018-05-01

Tumor growth and progression are critically dependent on the establishment of a vascular support system. This is often accomplished via the expression of pro-angiogenic growth factors, including members of the vascular endothelial growth factor (VEGF) family of ligands. VEGF ligands are overexpressed in a wide variety of solid tumors and therefore have inspired optimism that inhibition of the different axes of the VEGF pathway-alone or in combination-would represent powerful anti-angiogenic therapies for most cancer types. When considering treatments that target VEGF and its receptors, it is difficult to tease out the differential anti-angiogenic and anti-tumor effects of all combinations experimentally because tumor cells and vascular endothelial cells are engaged in a dynamic cross-talk that impacts key aspects of tumorigenesis, independent of angiogenesis. Here we develop a mathematical model that connects intracellular signaling responsible for both endothelial and tumor cell proliferation and death to population-level cancer growth and angiogenesis. We use this model to investigate the effect of bidirectional communication between endothelial cells and tumor cells on treatments targeting VEGF and its receptors both in vitro and in vivo. Our results underscore the fact that in vitro therapeutic outcomes do not always translate to the in vivo situation. For example, our model predicts that certain therapeutic combinations result in antagonism in vivo that is not observed in vitro. Mathematical modeling in this direction can shed light on the mechanisms behind experimental observations that manipulating VEGF and its receptors is successful in some cases but disappointing in others.

Polyradiomodification. Evaluation of the efficacy of the utilization of hyperglycemia in experimental hypoxiradiotherapy of tumors

International Nuclear Information System (INIS)

Kozin, S.V.; Dyuskaliev, Zh.D.; Yarmonenko, S.P.

1984-01-01

An experimental evaluation of the appropriateness of the use of short-term hyperglycemia combined with hypoxiradiotherapy of solid tumors is given. In comparing the response of tumors and overlying skin a conclusion has been made that gaseous hypoxia and the use of hyperglycemia separately yield in a considerable therapeutic benefit, and the use of the combination of these agents in some cases produces a greater therapeutic interval between tumor destruction and normal tissues. The mechanisms of the modification of radiation injuries of tumors and skin under the influence of the above two factors are discussed

Hypoxyradiotherapy: lack of experimental evidence for a preferential radioprotective effect on normal versus tumor tissue as shown by direct oxygenation measurements in experimental sarcomas

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Kelleher, Debra K.; Thews, Oliver; Vaupel, Peter

1997-01-01

Aim: In order to investigate possible pathophysiological mechanisms underlying the postulated preferential protective effect of hypoxia on normal tissue during radiotherapy, the impact of acute respiratory hypoxia (8.2% O 2 + 91.8% N 2 ) on tissue oxygenation was assessed. Methods: Tumor and normal tissue oxygenation was directly determined using O 2 -sensitive electrodes in two experimental rat tumors (DS and Yoshida sarcomas) and in the normal subcutis of the hind foot dorsum. Results: During respiratory hypoxia, arterial blood O 2 tension (pO 2 ), oxyhemoglobin saturation and mean arterial blood pressure decreased. Changes in the arterial blood gas status were accompanied by a reflex hyperventilation leading to hypocapnia and respiratory alkalosis. In the subcutis, tissue oxygenation worsened during acute hypoxia, with decreases in the mean and median pO 2 . Significant increases in the hypoxic fractions were, however, not seen. In tumor tissues, oxygenation also worsened upon hypoxic hypoxia with significant decreases in the mean and median pO 2 and increases in the size of the hypoxic fractions for both sarcomas. Conclusion: These results suggest that during respiratory hypoxia, radiobiologically relevant reductions in the oxygenation (and a subsequent selective radioprotection) of normal tissue may not be achieved. In addition, in the tumor models studied, a worsening of tumor oxygenation was seen which could result in an increased radioresistance

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...... the use of the intensity information in the training images. Experiments on public benchmark data of patients suffering from low- and high-grade gliomas show that the method performs well compared to current state-of-the-art methods, while not being tied to any specific imaging protocol....... 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...

Spherical Cancer Models in Tumor Biology

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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.

Extensive FDG uptake and its modification with corticosteroid in a granuloma rat model: an experimental study for differentiating granuloma from tumors

International Nuclear Information System (INIS)

Zhao, Songji; Takei, Toshiki; Zhao, Yan; Tamaki, Nagara; Kuge, Yuji; Kohanawa, Masashi; Takahashi, Toshiyuki; Kawashima, Hidekazu; Temma, Takashi; Seki, Koh-ichi

2007-01-01

Increased 18 F-fluorodeoxyglucose (FDG) uptake in inflammatory lesions, particularly in granulomatous inflammation (e.g., sarcoidosis), makes it difficult to differentiate malignant tumors from benign lesions and is the main source of false-positive FDG-PET findings in oncology. Here, we developed a rat granuloma model and examined FDG uptake in the granuloma. The effects of corticosteroid on FDG uptake in the granuloma were compared with those in a malignant tumor. Rats were inoculated with Mycobacterium bovis bacillus Calmette-Guerin (BCG) or allogenic hepatoma cells, and subdivided into control and pretreated (methylprednisolone acetate, 8 mg/kg i.m.) groups. Radioactivity in tissues was determined 1 h after the FDG injection. FDG-PET was performed in rats bearing BCG granulomas or tumors before and after prednisolone treatment. Mature epithelioid cell granuloma-formation and massive lymphocyte-infiltration were observed in the control group of granuloma, histologically similar to sarcoidosis. The mean FDG uptake in the granuloma was comparable to that in the hepatoma. Prednisolone reduced epithelioid cell granuloma-formation and lymphocyte-infiltration. Prednisolone significantly decreased the level of FDG uptake in the granuloma (52% of control), but not in the hepatoma. The FDG uptake levels in the granulomas and tumors were clearly imaged with PET. We developed an intramuscular granuloma rat model that showed a high FDG uptake comparable to that of the tumor. The effect of prednisolone pretreatment on FDG uptake was greater in the granuloma than in the tumor. These results suggest that BCG-induced granuloma may be a valuable model and may provide a biological basis for FDG studies. (orig.)

Ultraviolet radiation-induced carcinogenesis: mechanisms and experimental models

International Nuclear Information System (INIS)

Ramasamy, Karthikeyan; Shanmugam, Mohana; Balupillai, Agilan; Govindhasamy, Kanimozhi; Gunaseelan, Srithar; Muthusamy, Ganesan; Robert, Beualah Mary; Nagarajan, Rajendra Prasad

2017-01-01

Ultraviolet radiation (UVR) is a very prominent environmental toxic agent. UVR has been implicated in the initiation and progression of photocarcinogenesis. UVR exposure elicits numerous cellular and molecular events which include the generation of inflammatory mediators, DNA damage, epigenetic modifications, and oxidative damages mediated activation of signaling pathways. UVR-initiated signal transduction pathways are believed to be responsible for tumor promotion effects. UVR-induced carcinogenic mechanism has been well studied using various animal and cellular models. Human skin-derived dermal fibroblasts, epidermal keratinocytes, and melanocytes served as excellent cellular model systems for the understanding of UVR-mediated carcinogenic events. Apart from this, scientists developed reconstituted three-dimensional normal human skin equivalent models for the study of UVR signaling pathways. Moreover, hairless mice such as SKH-1, devoid of Hr gene, served as a valuable model for experimental carcinogenesis. Scientists have also used transgenic mice and dorsal portion shaved Swiss albino mice for UVR carcinogenesis studies. In this review, we have discussed the current progress in the study on ultraviolet B (UVB)-mediated carcinogenesis and outlined appropriate experimental models for both ultraviolet A- and UVB-mediated carcinogenesis. (author)

Radioiodinated VEGF to image tumor angiogenesis in a LS180 tumor xenograft model

International Nuclear Information System (INIS)

Yoshimoto, Mitsuyoshi; Kinuya, Seigo; Kawashima, Atsuhiro; Nishii, Ryuichi; Yokoyama, Kunihiko; Kawai, Keiichi

2006-01-01

Introduction: Angiogenesis is essential for tumor growth or metastasis. A method involving noninvasive detection of angiogenic activity in vivo would provide diagnostic information regarding antiangiogenic therapy targeting vascular endothelial cells as well as important insight into the role of vascular endothelial growth factor (VEGF) and its receptor (flt-1 and KDR) system in tumor biology. We evaluated radioiodinated VEGF 121 , which displays high binding affinity for KDR, and VEGF 165 , which possesses high binding affinity for flt-1 and low affinity for KDR, as angiogenesis imaging agents using the LS180 tumor xenograft model. Methods: VEGF 121 and VEGF 165 were labeled with 125 I by the chloramine-T method. Biodistribution was observed in an LS180 human colon cancer xenograft model. Additionally, autoradiographic imaging and immunohistochemical staining of tumors were performed with 125 I-VEGF 121 . Results: 125 I-VEGF 121 and 125 I-VEGF 165 exhibited strong, continuous uptake by tumors and the uterus, an organ characterized by angiogenesis. 125 I-VEGF 121 uptake in tumors was twofold higher than that of 125 I-VEGF 165 (9.12±98 and 4.79±1.08 %ID/g at 2 h, respectively). 125 I-VEGF 121 displayed higher tumor to nontumor (T/N) ratios in most normal organs in comparison with 125 I-VEGF 165 . 125 I-VEGF 121 accumulation in tumors decreased with increasing tumor volume. Autoradiographic and immunohistochemical analyses confirmed that the difference in 125 I-VEGF 121 tumor accumulation correlated with degree of tumor vascularity. Conclusion: Radioiodinated VEGF 121 is a promising tracer for noninvasive delineation of angiogenesis in vivo

Dendritic cell-based vaccines for the therapy of experimental tumors

Czech Academy of Sciences Publication Activity Database

Piasecka, E.P.; Indrová, Marie

2010-01-01

Roč. 2, č. 2 (2010), s. 257-268 ISSN 1750-743X R&D Projects: GA AV ČR IAA500520807; GA ČR GA301/09/1024; GA MZd NS10660 Grant - others:Polish Ministry of Science and Higher Education(PL) NN401235334 Institutional research plan: CEZ:AV0Z50520514 Keywords : dendritic cells * preparation of vaccines * experimental tumors Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 0.542, year: 2010

Therapeutic Implications from Sensitivity Analysis of Tumor Angiogenesis Models

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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

In Vivo Imaging of Experimental Melanoma Tumors using the Novel Radiotracer 68Ga-NODAGA-Procainamide (PCA).

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Kertész, István; Vida, András; Nagy, Gábor; Emri, Miklós; Farkas, Antal; Kis, Adrienn; Angyal, János; Dénes, Noémi; Szabó, Judit P; Kovács, Tünde; Bai, Péter; Trencsényi, György

2017-01-01

The most aggressive form of skin cancer is the malignant melanoma. Because of its high metastatic potential the early detection of primary melanoma tumors and metastases using non-invasive PET imaging determines the outcome of the disease. Previous studies have already shown that benzamide derivatives, such as procainamide (PCA) specifically bind to melanin pigment. The aim of this study was to synthesize and investigate the melanin specificity of the novel 68 Ga-labeled NODAGA-PCA molecule in vitro and in vivo using PET techniques. Procainamide (PCA) was conjugated with NODAGA chelator and was labeled with Ga-68 ( 68 Ga-NODAGA-PCA). The melanin specificity of 68 Ga-NODAGA-PCA was tested in vitro , ex vivo and in vivo using melanotic B16-F10 and amelanotic Melur melanoma cell lines. By subcutaneous and intravenous injection of melanoma cells tumor-bearing mice were prepared, on which biodistribution studies and small animal PET/CT scans were performed for 68 Ga-NODAGA-PCA and 18 FDG tracers. 68 Ga-NODAGA-PCA was produced with high specific activity (14.9±3.9 GBq/µmol) and with excellent radiochemical purity (98%PCA uptake of B16-F10 cells was significantly ( p ≤0.01) higher than Melur cells. Ex vivo biodistribution and in vivo PET/CT studies using subcutaneous and metastatic tumor models showed significantly ( p ≤0.01) higher 68 Ga-NODAGA-PCA uptake in B16-F10 primary tumors and lung metastases in comparison with amelanotic Melur tumors. In experiments where 18 FDG and 68 Ga-NODAGA-PCA uptake of B16-F10 tumors was compared, we found that the tumor-to-muscle (T/M) and tumor-to-lung (T/L) ratios were significantly ( p ≤0.05 and p ≤0.01) higher using 68 Ga-NODAGA-PCA than the 18 FDG accumulation. Our novel radiotracer 68 Ga-NODAGA-PCA showed specific binding to the melanin producing experimental melanoma tumors. Therefore, 68 Ga-NODAGA-PCA is a suitable diagnostic radiotracer for the detection of melanoma tumors and metastases in vivo .

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.

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

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Malinowski, Kathleen T. [Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD (United States); Fischell Department of Bioengineering, University of Maryland, College Park, MD (United States); McAvoy, Thomas J. [Fischell Department of Bioengineering, University of Maryland, College Park, MD (United States); Department of Chemical and Biomolecular Engineering and Institute of Systems Research, University of Maryland, College Park, MD (United States); George, Rohini [Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD (United States); Dieterich, Sonja [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA (United States); D' Souza, Warren D., E-mail: wdsou001@umaryland.edu [Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD (United States); Fischell Department of Bioengineering, University of Maryland, College Park, MD (United States)

2012-04-01

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.

Interstitial fluid flow and drug delivery in vascularized tumors: a computational model.

Directory of Open Access Journals (Sweden)

Michael Welter

Full Text Available Interstitial fluid is a solution that bathes and surrounds the human cells and provides them with nutrients and a way of waste removal. It is generally believed that elevated tumor interstitial fluid pressure (IFP is partly responsible for the poor penetration and distribution of therapeutic agents in solid tumors, but the complex interplay of extravasation, permeabilities, vascular heterogeneities and diffusive and convective drug transport remains poorly understood. Here we consider-with the help of a theoretical model-the tumor IFP, interstitial fluid flow (IFF and its impact upon drug delivery within tumor depending on biophysical determinants such as vessel network morphology, permeabilities and diffusive vs. convective transport. We developed a vascular tumor growth model, including vessel co-option, regression, and angiogenesis, that we extend here by the interstitium (represented by a porous medium obeying Darcy's law and sources (vessels and sinks (lymphatics for IFF. With it we compute the spatial variation of the IFP and IFF and determine its correlation with the vascular network morphology and physiological parameters like vessel wall permeability, tissue conductivity, distribution of lymphatics etc. We find that an increased vascular wall conductivity together with a reduction of lymph function leads to increased tumor IFP, but also that the latter does not necessarily imply a decreased extravasation rate: Generally the IF flow rate is positively correlated with the various conductivities in the system. The IFF field is then used to determine the drug distribution after an injection via a convection diffusion reaction equation for intra- and extracellular concentrations with parameters guided by experimental data for the drug Doxorubicin. We observe that the interplay of convective and diffusive drug transport can lead to quite unexpected effects in the presence of a heterogeneous, compartmentalized vasculature. Finally we discuss

Interstitial fluid flow and drug delivery in vascularized tumors: a computational model.

Science.gov (United States)

Welter, Michael; Rieger, Heiko

2013-01-01

Interstitial fluid is a solution that bathes and surrounds the human cells and provides them with nutrients and a way of waste removal. It is generally believed that elevated tumor interstitial fluid pressure (IFP) is partly responsible for the poor penetration and distribution of therapeutic agents in solid tumors, but the complex interplay of extravasation, permeabilities, vascular heterogeneities and diffusive and convective drug transport remains poorly understood. Here we consider-with the help of a theoretical model-the tumor IFP, interstitial fluid flow (IFF) and its impact upon drug delivery within tumor depending on biophysical determinants such as vessel network morphology, permeabilities and diffusive vs. convective transport. We developed a vascular tumor growth model, including vessel co-option, regression, and angiogenesis, that we extend here by the interstitium (represented by a porous medium obeying Darcy's law) and sources (vessels) and sinks (lymphatics) for IFF. With it we compute the spatial variation of the IFP and IFF and determine its correlation with the vascular network morphology and physiological parameters like vessel wall permeability, tissue conductivity, distribution of lymphatics etc. We find that an increased vascular wall conductivity together with a reduction of lymph function leads to increased tumor IFP, but also that the latter does not necessarily imply a decreased extravasation rate: Generally the IF flow rate is positively correlated with the various conductivities in the system. The IFF field is then used to determine the drug distribution after an injection via a convection diffusion reaction equation for intra- and extracellular concentrations with parameters guided by experimental data for the drug Doxorubicin. We observe that the interplay of convective and diffusive drug transport can lead to quite unexpected effects in the presence of a heterogeneous, compartmentalized vasculature. Finally we discuss various

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

Basic fibroblast growth factor in an animal model of spontaneous mammary tumor progression.

Science.gov (United States)

Kao, Steven; Mo, Jeffrey; Baird, Andrew; Eliceiri, Brian P

2012-06-01

Although basic fibroblast growth factor (FGF2) was the first pro-angiogenic molecule discovered, it has numerous activities on the growth and differentiation of non-vascular cell types. FGF2 is both stimulatory and inhibitory, depending on the cell type evaluated, the experimental design used and the context in which it is tested. Here, we investigated the effects of manipulating endogenous FGF2 on the development of mammary cancer to determine whether its endogenous contribution in vivo is pro- or anti-tumorigenic. Specifically, we examined the effects of FGF2 gene dosing in a cross between a spontaneous breast tumor model (PyVT+ mice) and FGF2-/- (FGF KO) mice. Using these mice, the onset and progression of mammary tumors was determined. As predicted, female FGF2 WT mice developed mammary tumors starting around 60 days after birth and by 80 days, 100% of FGF2 WT female mice had mammary tumors. In contrast, 80% of FGF2 KO female mice had no palpable tumors until nearly three weeks later (85 days) at times when 100% of the WT cohort was tumor positive. All FGF KO mice were tumor-bearing by 115 days. When we compared the onset of mammary tumor development and the tumor progression curves between FGF het and FGF KO mice, we observed a difference, which suggested a gene dosing effect. Analysis of the tumors demonstrated that there were significant differences in tumor size depending on FGF2 status. The delay in tumor onset supports a functional role for FGF2 in mammary tumor progression, but argues against an essential role for FGF2 in overall mammary tumor progression.

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

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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.

Iodine-125 Seeds Strand for Treatment of Tumor Thrombus in Inferior Vena Cava: An Experimental Study in a Rabbit Model

International Nuclear Information System (INIS)

Zhang, Wen; Yan, Zhiping; Luo, Jianjun; Fang, Zhuting; Wu, Linlin; Liu, QingXin; Qu, Xudong; Liu, Lingxiao; Wang, Jianhua

2013-01-01

Objective: The purpose of this study was to establish an animal model of implanted inferior vena cava tumor thrombus (IVCTT) and to evaluate the effect of linear iodine-125 seeds strand in treating implanted IVCTT. Methods: Tumor cell line VX 2 was inoculated subcutaneously into New Zealand rabbit to develop the parent tumor. The tumor strip was inoculated into inferior vena cava (IVC) to establish the IVCTT model. The IVCTT was confirmed by multidetector computed tomography (MDCT) after 2 weeks. Twelve rabbits with IVCTT were randomly divided into two groups. Treatment group (group T; n = 6) underwent Iodine-125 seeds brachytherapy, and the control group (group C; n = 6) underwent blank seeds strand. The blood laboratory examination (including blood routine examination, hepatic and renal function), body weight, survival time, and IVCTT volume by MDCT were monitored. All rabbits were dissected postmortem, and the therapeutic effects were evaluated on the basis of histopathology. The proliferating cell nuclear antigen index (PI) and apoptosis index (AI) of IVCTT were compared between two groups. T test, Wilcoxon rank test, and Kaplan–Meier survival curve analysis were used. Results: The success rate of establishing IVCTT was 100 %. The body weight loss and cachexia of rabbits in group C appeared earlier than in group T. Body weight in the third week, the mean survival time, PI, AI in groups T and C were 2.23 ± 0.12 kg, 57.83 ± 8.68 days, (16.73 ± 5.18 %), (29.47 ± 7.18 %), and 2.03 ± 0.13 kg, 43.67 ± 5.28 days, (63.01 ± 2.01 %), (6.02 ± 2.93 %), respectively. There were statistically significant differences between group T and group C (P < 0.05). The IVCTT volume of group T was remarkably smaller than that of group C. Conclusions: Injecting and suspensory fixing VX2 tumor strip into IVC is a reliable method to establish IVCTT animal model. The linear Iodine-125 seeds strand brachytherapy was a safe and effective method for treating IVCTT in rabbit model

Iodine-125 Seeds Strand for Treatment of Tumor Thrombus in Inferior Vena Cava: An Experimental Study in a Rabbit Model

Energy Technology Data Exchange (ETDEWEB)

Zhang, Wen; Yan, Zhiping; Luo, Jianjun; Fang, Zhuting; Wu, Linlin; Liu, QingXin; Qu, Xudong; Liu, Lingxiao; Wang, Jianhua [Fudan University, Department of Interventional Radiology, Zhongshan Hospital (China)

2013-10-15

Objective: The purpose of this study was to establish an animal model of implanted inferior vena cava tumor thrombus (IVCTT) and to evaluate the effect of linear iodine-125 seeds strand in treating implanted IVCTT. Methods: Tumor cell line VX{sub 2} was inoculated subcutaneously into New Zealand rabbit to develop the parent tumor. The tumor strip was inoculated into inferior vena cava (IVC) to establish the IVCTT model. The IVCTT was confirmed by multidetector computed tomography (MDCT) after 2 weeks. Twelve rabbits with IVCTT were randomly divided into two groups. Treatment group (group T; n = 6) underwent Iodine-125 seeds brachytherapy, and the control group (group C; n = 6) underwent blank seeds strand. The blood laboratory examination (including blood routine examination, hepatic and renal function), body weight, survival time, and IVCTT volume by MDCT were monitored. All rabbits were dissected postmortem, and the therapeutic effects were evaluated on the basis of histopathology. The proliferating cell nuclear antigen index (PI) and apoptosis index (AI) of IVCTT were compared between two groups. T test, Wilcoxon rank test, and Kaplan-Meier survival curve analysis were used. Results: The success rate of establishing IVCTT was 100 %. The body weight loss and cachexia of rabbits in group C appeared earlier than in group T. Body weight in the third week, the mean survival time, PI, AI in groups T and C were 2.23 {+-} 0.12 kg, 57.83 {+-} 8.68 days, (16.73 {+-} 5.18 %), (29.47 {+-} 7.18 %), and 2.03 {+-} 0.13 kg, 43.67 {+-} 5.28 days, (63.01 {+-} 2.01 %), (6.02 {+-} 2.93 %), respectively. There were statistically significant differences between group T and group C (P < 0.05). The IVCTT volume of group T was remarkably smaller than that of group C. Conclusions: Injecting and suspensory fixing VX2 tumor strip into IVC is a reliable method to establish IVCTT animal model. The linear Iodine-125 seeds strand brachytherapy was a safe and effective method for treating IVCTT

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.

Cyclosporin safety in a simplified rat brain tumor implantation model

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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.

The bivariate probit model of uncomplicated control of tumor: a heuristic exposition of the methodology

International Nuclear Information System (INIS)

Herbert, Donald

1997-01-01

Purpose: To describe the concept, models, and methods for the construction of estimates of joint probability of uncomplicated control of tumors in radiation oncology. Interpolations using this model can lead to the identification of more efficient treatment regimens for an individual patient. The requirement to find the treatment regimen that will maximize the joint probability of uncomplicated control of tumors suggests a new class of evolutionary experimental designs--Response Surface Methods--for clinical trials in radiation oncology. Methods and Materials: The software developed by Lesaffre and Molenberghs is used to construct bivariate probit models of the joint probability of uncomplicated control of cancer of the oropharynx from a set of 45 patients for each of whom the presence/absence of recurrent tumor (the binary event E-bar 1 /E 1 ) and the presence/absence of necrosis (the binary event E 2 /E-bar 2 ) of the normal tissues of the target volume is recorded, together with the treatment variables dose, time, and fractionation. Results: The bivariate probit model can be used to select a treatment regime that will give a specified probability, say P(S) = 0.60, of uncomplicated control of tumor by interpolation within a set of treatment regimes with known outcomes of recurrence and necrosis. The bivariate probit model can be used to guide a sequence of clinical trials to find the maximum probability of uncomplicated control of tumor for patients in a given prognostic stratum using Response Surface methods by extrapolation from an initial set of treatment regimens. Conclusions: The design of treatments for individual patients and the design of clinical trials might be improved by use of a bivariate probit model and Response Surface Methods

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.

Effects of exercise on tumor physiology and metabolism

DEFF Research Database (Denmark)

Pedersen, Line; Christensen, Jesper Frank; Hojman, Pernille

2015-01-01

. Here, we review the body of literature describing exercise intervention studies performed in rodent tumor models and elaborate on potential mechanistic effects of exercise on tumor physiology. Exercise has been shown to reduce tumor incidence, tumor multiplicity, and tumor growth across numerous...... different transplantable, chemically induced or genetic tumor models. We propose 4 emerging mechanistic effects of exercise, including (1) vascularization and blood perfusion, (2) immune function, (3) tumor metabolism, and (4) muscle-to-cancer cross-talk, and discuss these in details. In conclusion......, exercise training has the potential to be a beneficial and integrated component of cancer management, but has yet to fully elucidate its potential. Understanding the mechanistic effects of exercise on tumor physiology is warranted. Insight into these mechanistic effects is emerging, but experimental...

Predictive value of histologic tumor necrosis after radiation.

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Chen, Y; Taghian, A G; Rosenberg, A E; O'Connell, J; Okunieff, P; Suit, H D

2001-12-20

Postsurgical evaluation of histologic changes of tumors after preoperative chemotherapy and/or radiotherapy has been a routine clinical practice of pathologists and oncologists. There appears to be secure evidence that the extent of tumor necrosis vs. viable tumor cells postchemotherapy is a clinically useful predictor of outcome. The significance of histologic tumor necrosis after radiotherapy, however, has not been clearly established and deserves further investigation. We investigated the correlation between histological extent of tumor necrosis, survival of tumor transplants, and radiation doses in an experimental model using three human tumor xenografts. Three human tumor cell lines were investigated: STS-26, SCC-21, and HGL-21. Tumors were grown subcutaneously in athymic nude mice and received external beam radiation of different doses. Tumors were excised 2 weeks postirradiation. One-half of the tumor was divided into 1-mm(3) fragments and transplanted to naive mice. The other half was examined for histologic tumor necrosis. Transplant survival was strongly correlated with radiation dose, TCD(p) (radiation dose that results in local tumor control in proportion, p, to irradiated tumors). In contrast, there was no clear association between transplant survival rate and the extent of tumor necrosis. The experimental model demonstrated a strong inverse correlation between radiation doses and tumor transplant survival. Histologic tumor necrosis did not correlate well with radiation doses or transplant survival rates. Despite common practices in histologic examination of tumors posttherapy, clinical interpretations and implications of histologic tumor necrosis after radiotherapy should be considered with caution. Copyright 2001 Wiley-Liss, Inc.

Implementation of plaid model biclustering method on microarray of carcinoma and adenoma tumor gene expression data

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Ardaneswari, Gianinna; Bustamam, Alhadi; Sarwinda, Devvi

2017-10-01

A Tumor is an abnormal growth of cells that serves no purpose. Carcinoma is a tumor that grows from the top of the cell membrane and the organ adenoma is a benign tumor of the gland-like cells or epithelial tissue. In the field of molecular biology, the development of microarray technology is used in the data store of disease genetic expression. For each of microarray gene, an amount of information is stored for each trait or condition. In gene expression data clustering can be done with a bicluster algorithm, thats clustering method which not only the objects to be clustered, but also the properties or condition of the object. This research proposed Plaid Model Biclustering as one of biclustering method. In this study, we discuss the implementation of Plaid Model Biclustering Method on microarray of Carcinoma and Adenoma tumor gene expression data. From the experimental results, we found three biclusters are formed by Carcinoma gene expression data and four biclusters are formed by Adenoma gene expression data.

The effects of profound hypothermia on pancreas ischemic injury: a new experimental model.

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Rocha-Santos, Vinicius; Ferro, Oscar Cavalcante; Pantanali, Carlos Andrés; Seixas, Marcel Povlovistsch; Pecora, Rafael Antonio Arruda; Pinheiro, Rafael Soares; Claro, Laura Carolina López; Abdo, Emílio Elias; Chaib, Eleazar; D'Albuquerque, Luiz Augusto Carneiro

2014-08-01

Pancreatic ischemia-reperfusion (IR) has a key role in pancreas surgery and transplantation. Most experimental models evaluate the normothermic phase of the IR. We proposed a hypothermic model of pancreas IR to evaluate the benefic effects of the cold ischemic phase. We performed a reproducible model of hypothermic pancreatic IR. The ischemia was induced in the pancreatic tail portion (1-hour ischemia, 4-hour reperfusion) in 36 Wistar rats. They are divided in 3 groups as follows: group 1 (control), sham; group 2, normothermic IR; and group 3, hypothermic IR. In group 3, the temperature was maintained as close to 4.5°C. After reperfusion, serum amylase and lipase levels, inflammatory mediators (tumor necrosis factor α, interleukin 6), and pancreas histology were evaluated. In pancreatic IR groups, amylase, cytokines, and histological damage were significantly increased when compared with group 1. In the group 3, we observed a significant decrease in tumor necrosis factor α (P = 0.004) and interleukin 6 (P = 0.001) when compared with group 2. We did not observe significant difference in amylase (P = 0.867), lipase (P = 0.993), and histology (P = 0.201). In our experimental model, we reproduced the cold phase of pancreas IR, and the pancreas hypothermia reduced the inflammatory mediators after reperfusion.

Tobacco experimental model to induce urinary bladder neoplasms

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José Alexandre Colli Neto

2014-01-01

Full Text Available OBJECTIVE: to develop an experimental model of exposure to tobacco burning (cigarette products to assess the effects of its chronic use in relation to cancers of the bladder. METHODS: the animals were chronically exposed to the burning tobacco products in a semi-open chamber to simulate smoking. Thirty young Wistar rats were divided into two groups: one with 20 animals simulating smoking for six months, and ten not exposed control animals for the same period. After exposure by inhalation of cigarette smoke, animals were euthanized and subjected to histopathological study of the bladder wall. RESULTS: no tumor was found but mild and non significant alterations. The studies of hemo-oximetry (carboxyhemoglobin and methemoglobin and the concentration of carbon dioxide (CO2 confirm that the animals were exposed to high concentrations of tobacco smoke and its derivatives. CONCLUSION: no bladder mucosal neoplasia was found in the pathological study of animals. The developed experimental models were highly efficient, practical and easy to use and can be used in other similar studies to determine the harmful effects caused by smoking.

Toward in vivo lung's tissue incompressibility characterization for tumor motion modeling in radiation therapy

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Shirzadi, Zahra; Sadeghi-Naini, Ali; Samani, Abbas

2013-01-01

the tumor motion trajectory and its final locations obtained from simulations with and without considering tissue incompressibility variation were very different. For example, tumor displacements in the z direction were −11.23 and −38.10 mm obtained with the Marlow hyperelastic material model in conjunction with constant and variable Poisson's ratio, respectively. By comparing the acquired 4D-CT image sequence of the porcine lung with their image sequence counterparts obtained from the hyperelastic model with constant and variable Poisson's ratio, it was shown that using variable tissue incompressibility reduced errors significantly in tumor motion prediction. Conclusions: This investigation demonstrates the importance of incompressibility variation estimation and utilization for accurate tumor tracking in computer assisted lung external beam radiation therapy. An optimization framework was developed to estimate a Poisson's ratio function in terms of respiration cycle time using experimental image data of the lung. Utilizing this function along with respiratory system FE modeling may lead to more effective tumor targeting, hence potentially improving the outcome of lung external beam radiation therapy techniques. This is particularly true for stereotactic body radiation therapy where only one or a few fraction treatments are applied, precluding the possibility of averaging out dosimetric deviations introduced by the respiratory motion.

Model construction of nursing service satisfaction in hospitalized tumor patients.

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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.

Geometrical approach to tumor growth.

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Escudero, Carlos

2006-08-01

Tumor growth has a number of features in common with a physical process known as molecular beam epitaxy. Both growth processes are characterized by the constraint of growth development to the body border, and surface diffusion of cells and particles at the growing edge. However, tumor growth implies an approximate spherical symmetry that makes necessary a geometrical treatment of the growth equations. The basic model was introduced in a former paper [C. Escudero, Phys. Rev. E 73, 020902(R) (2006)], and in the present work we extend our analysis and try to shed light on the possible geometrical principles that drive tumor growth. We present two-dimensional models that reproduce the experimental observations, and analyze the unexplored three-dimensional case, for which interesting conclusions on tumor growth are derived.

A realistic closed-form radiobiological model of clinical tumor-control data incorporating intertumor heterogeneity

International Nuclear Information System (INIS)

Roberts, Stephen A.; Hendry, Jolyon H.

1998-01-01

Purpose: To investigate the role of intertumor heterogeneity in clinical tumor control datasets and the relationship to in vitro measurements of tumor biopsy samples. Specifically, to develop a modified linear-quadratic (LQ) model incorporating such heterogeneity that it is practical to fit to clinical tumor-control datasets. Methods and Materials: We developed a modified version of the linear-quadratic (LQ) model for tumor control, incorporating a (lagged) time factor to allow for tumor cell repopulation. We explicitly took into account the interpatient heterogeneity in clonogen number, radiosensitivity, and repopulation rate. Using this model, we could generate realistic TCP curves using parameter estimates consistent with those reported from in vitro studies, subject to the inclusion of a radiosensitivity (or dose)-modifying factor. We then demonstrated that the model was dominated by the heterogeneity in α (tumor radiosensitivity) and derived an approximate simplified model incorporating this heterogeneity. This simplified model is expressible in a compact closed form, which it is practical to fit to clinical datasets. Using two previously analysed datasets, we fit the model using direct maximum-likelihood techniques and obtained parameter estimates that were, again, consistent with the experimental data on the radiosensitivity of primary human tumor cells. This heterogeneity model includes the same number of adjustable parameters as the standard LQ model. Results: The modified model provides parameter estimates that can easily be reconciled with the in vitro measurements. The simplified (approximate) form of the heterogeneity model is a compact, closed-form probit function that can readily be fitted to clinical series by conventional maximum-likelihood methodology. This heterogeneity model provides a slightly better fit to the datasets than the conventional LQ model, with the same numbers of fitted parameters. The parameter estimates of the clinically

Selection, calibration, and validation of models of tumor growth.

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Lima, E A B F; Oden, J T; Hormuth, D A; Yankeelov, T E; Almeida, R C

2016-11-01

This paper presents general approaches for addressing some of the most important issues in predictive computational oncology concerned with developing classes of predictive models of tumor growth. First, the process of developing mathematical models of vascular tumors evolving in the complex, heterogeneous, macroenvironment of living tissue; second, the selection of the most plausible models among these classes, given relevant observational data; third, the statistical calibration and validation of models in these classes, and finally, the prediction of key Quantities of Interest (QOIs) relevant to patient survival and the effect of various therapies. The most challenging aspects of this endeavor is that all of these issues often involve confounding uncertainties: in observational data, in model parameters, in model selection, and in the features targeted in the prediction. Our approach can be referred to as "model agnostic" in that no single model is advocated; rather, a general approach that explores powerful mixture-theory representations of tissue behavior while accounting for a range of relevant biological factors is presented, which leads to many potentially predictive models. Then representative classes are identified which provide a starting point for the implementation of OPAL, the Occam Plausibility Algorithm (OPAL) which enables the modeler to select the most plausible models (for given data) and to determine if the model is a valid tool for predicting tumor growth and morphology ( in vivo ). All of these approaches account for uncertainties in the model, the observational data, the model parameters, and the target QOI. We demonstrate these processes by comparing a list of models for tumor growth, including reaction-diffusion models, phase-fields models, and models with and without mechanical deformation effects, for glioma growth measured in murine experiments. Examples are provided that exhibit quite acceptable predictions of tumor growth in laboratory

A Big Bang model of human colorectal tumor growth.

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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.

Tumor Microenvironment In Experimental Models Of Human Cancer: Morphological Investigational Approaches

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Lucia Minoli

2017-05-01

Discussion and conclusions. Due to the microenvironmental heterogeneity which influence tumor development and biological behavior, a sole quantification is unreliable for characterizing the TME. Considering that, morphological techniques proved to be a valuable approach, allowing the evaluation of the spatial distribution and mutual interaction between the different elements. Additional studies are needed for further investigate the biological significance of spatial distribution of the components of the TME.

Experimental Object-Oriented Modelling

DEFF Research Database (Denmark)

Hansen, Klaus Marius

through, e.g., technical prototyping and active user involvement. We introduce and examine “experimental object-oriented modelling” as the intersection of these practices. The contributions of this thesis are expected to be within three perspectives on models and modelling in experimental system...... development: Grounding We develop an empirically based conceptualization of modelling and use of models in system development projects characterized by a high degree of uncertainty in requirements and point to implications for tools and techniques for modelling in such a setting. Techniques We introduce......This thesis examines object-oriented modelling in experimental system development. Object-oriented modelling aims at representing concepts and phenomena of a problem domain in terms of classes and objects. Experimental system development seeks active experimentation in a system development project...

Qualitative and Computational Analysis of a Mathematical Model for Tumor-Immune Interactions

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F. A. Rihan

2012-01-01

Full Text Available We provide a family of ordinary and delay differential equations to model the dynamics of tumor-growth and immunotherapy interactions. We explore the effects of adoptive cellular immunotherapy on the model and describe under what circumstances the tumor can be eliminated. The possibility of clearing the tumor, with a strategy, is based on two parameters in the model: the rate of influx of the effector cells and the rate of influx of IL-2. The critical tumor-growth rate, below which endemic tumor does not exist, has been found. One can use the model to make predictions about tumor dormancy.

Boron neutron capture therapy (BNCT) inhibits tumor development from precancerous tissue: An experimental study that supports a potential new application of BNCT

International Nuclear Information System (INIS)

Monti Hughes, A.; Heber, E.M.; Pozzi, E.; Nigg, D.W.; Calzetta, O.; Blaumann, H.; Longhino, J.; Nievas, S.I.; Aromando, R.F.; Itoiz, M.E.; Trivillin, V.A.; Schwint, A.E.

2009-01-01

We previously demonstrated the efficacy of boron neutron capture therapy (BNCT) mediated by boronophenylalanine (BPA), GB-10 (Na 2 10 B 10 H 10 ) and (GB-10+BPA) to control tumors, with no normal tissue radiotoxicity, in the hamster cheek pouch oral cancer model. Herein we developed a novel experimental model of field-cancerization and precancerous lesions (globally termed herein precancerous tissue) in the hamster cheek pouch to explore the long-term potential inhibitory effect of the same BNCT protocols on the development of second primary tumors from precancerous tissue. Clinically, second primary tumor recurrences occur in field-cancerized tissue, causing therapeutic failure. We performed boron biodistribution studies followed by in vivo BNCT studies, with 8 months follow-up. All 3 BNCT protocols induced a statistically significant reduction in tumor development from precancerous tissue, reaching a maximum inhibition of 77-100%. The inhibitory effect of BPA-BNCT and (GB-10+BPA)-BNCT persisted at 51% at the end of follow-up (8 months), whereas for GB-10-BNCT it faded after 2 months. Likewise, beam-only elicited a significant but transient reduction in tumor development. No normal tissue radiotoxicity was observed. At 8 months post-treatment with BPA-BNCT or (GB-10+BPA)-BNCT, the precancerous pouches that did not develop tumors had regained the macroscopic and histological appearance of normal (non-cancerized) pouches. A potential new clinical application of BNCT would lie in its capacity to inhibit local regional recurrences.

Boron neutron capture therapy (BNCT) inhibits tumor development from precancerous tissue: An experimental study that supports a potential new application of BNCT

Energy Technology Data Exchange (ETDEWEB)

Monti Hughes, A.; Heber, E.M. [Department of Radiobiology, National Atomic Energy Commission (CNEA), Buenos Aires (Argentina); Pozzi, E. [Department of Radiobiology, National Atomic Energy Commission (CNEA), Buenos Aires (Argentina); Department of Research and Production Reactors, Ezeiza Atomic Center, CNEA, Buenos Aires (Argentina); Nigg, D.W. [Idaho National Laboratory, Idaho Falls, Idaho (United States); Calzetta, O.; Blaumann, H.; Longhino, J. [Department of Nuclear Engineering, Bariloche Atomic Center, CNEA, Rio Negro (Argentina); Nievas, S.I. [Department of Chemistry, CNEA, Buenos Aires (Argentina); Aromando, R.F. [Department of Oral Pathology, Faculty of Dentistry, University of Buenos Aires, Buenos Aires (Argentina); Itoiz, M.E. [Department of Radiobiology, National Atomic Energy Commission (CNEA), Buenos Aires (Argentina); Department of Oral Pathology, Faculty of Dentistry, University of Buenos Aires, Buenos Aires (Argentina); Trivillin, V.A. [Department of Radiobiology, National Atomic Energy Commission (CNEA), Buenos Aires (Argentina); Schwint, A.E. [Department of Radiobiology, National Atomic Energy Commission (CNEA), Buenos Aires (Argentina)], E-mail: schwint@cnea.gov.ar

2009-07-15

We previously demonstrated the efficacy of boron neutron capture therapy (BNCT) mediated by boronophenylalanine (BPA), GB-10 (Na{sub 2}{sup 10}B{sub 10}H{sub 10}) and (GB-10+BPA) to control tumors, with no normal tissue radiotoxicity, in the hamster cheek pouch oral cancer model. Herein we developed a novel experimental model of field-cancerization and precancerous lesions (globally termed herein precancerous tissue) in the hamster cheek pouch to explore the long-term potential inhibitory effect of the same BNCT protocols on the development of second primary tumors from precancerous tissue. Clinically, second primary tumor recurrences occur in field-cancerized tissue, causing therapeutic failure. We performed boron biodistribution studies followed by in vivo BNCT studies, with 8 months follow-up. All 3 BNCT protocols induced a statistically significant reduction in tumor development from precancerous tissue, reaching a maximum inhibition of 77-100%. The inhibitory effect of BPA-BNCT and (GB-10+BPA)-BNCT persisted at 51% at the end of follow-up (8 months), whereas for GB-10-BNCT it faded after 2 months. Likewise, beam-only elicited a significant but transient reduction in tumor development. No normal tissue radiotoxicity was observed. At 8 months post-treatment with BPA-BNCT or (GB-10+BPA)-BNCT, the precancerous pouches that did not develop tumors had regained the macroscopic and histological appearance of normal (non-cancerized) pouches. A potential new clinical application of BNCT would lie in its capacity to inhibit local regional recurrences.

Experimental induction of ovarian Sertoli cell tumors in rats by N-nitrosoureas.

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Maekawa, A; Onodera, H; Tanigawa, H; Furuta, K; Kanno, J; Ogiu, T; Hayashi, Y

1987-01-01

Spontaneous ovarian tumors are very rare in ACI, Wistar, F344 and Donryu rats; the few neoplasms found are of the granulosa/theca cell type. Ovarian tumors were also rare in these strains of rats when given high doses of N-alkyl-N-nitrosoureas continuously in the drinking water for their life-span; however, relatively high incidences of Sertoli cell tumors or Sertoli cell tumors mixed with granulosa cell tumors were induced in Donryu rats after administration of either a 400 ppm N-ethyl-N-nitrosourea solution in the drinking water for 4 weeks or as a single dose of 200 mg N-propyl-N-nitrosourea per kg body weight by stomach tube. Typical Sertoli cell tumors consisted of solid areas showing tubular formation. The tubules were lined by tall, columnar cells, with abundant, faintly eosinophilic, often vacuolated cytoplasm, and basally oriented, round nuclei, resembling seminiferous tubules in the testes. In some cases, Sertoli cell tumor elements were found mixed with areas of granulosa cells. The induction of ovarian Sertoli cell tumors in Donryu rats by low doses of nitrosoureas may provide a useful model for these tumors in man. Images PLATE 1. PLATE 2. PLATE 3. PLATE 4. PLATE 5. PLATE 6. PLATE 7. PLATE 8. PLATE 9. PLATE 10. PLATE 11. PLATE 12. PLATE 13. PLATE 14. PLATE 15. PLATE 16. PMID:3665856

Experimental study of chemical embolus therapy combined with radiotherapy for VX2 bone tumors

International Nuclear Information System (INIS)

Yamaguchi, Hiroshi; Mochizuki, Kazuo; Ishii, Yoshiaki

2000-01-01

We conducted an experimental study, using a combination of coarse crystal cisplatin and radiotherapy for bone tumors, to evaluate the possibility of the clinical application of chemical embolus therapy in the field of orthopedic surgery. Experimental femoral bone tumors were produced, in rabbits, using VX2 carcinoma. The rabbits were allocated to five groups: untreated control, embolus, chemical embolus, irradiation alone, and chemical embolus and irradiation combination. These therapies were evaluated comparatively, in terms of local antitumor effects (including body weight, X-ray findings, angiography, and histopathology) and in terms of inhibition of pulmonary metastasis. Local antitumor effects, as evaluated by all parameters, except for body weight, were significantly greater for the chemical and irradiation combination group than for the chemical embolus, irradiation alone, untreated control, and embolus groups. There was no significant difference in the inhibition of pulmonary metastasis among the chemical embolus and irradiation combination, chemical embolus, and irradiation alone groups. These findings demonstrated the synergistic effect of the combination of chemical embolus therapy and radiotherapy. In this study, however, no significant difference was found between the chemical embolus therapy alone and the combination therapy groups in the inhibitory effect on pulmonary tumor metastasis, suggesting the need to conduct combination therapy repeatedly in the clinical setting. (author)

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

On the Inclusion of Short-distance Bystander Effects into a Logistic Tumor Control Probability Model.

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Tempel, David G; Brodin, N Patrik; Tomé, Wolfgang A

2018-01-01

Currently, interactions between voxels are neglected in the tumor control probability (TCP) models used in biologically-driven intensity-modulated radiotherapy treatment planning. However, experimental data suggests that this may not always be justified when bystander effects are important. We propose a model inspired by the Ising model, a short-range interaction model, to investigate if and when it is important to include voxel to voxel interactions in biologically-driven treatment planning. This Ising-like model for TCP is derived by first showing that the logistic model of tumor control is mathematically equivalent to a non-interacting Ising model. Using this correspondence, the parameters of the logistic model are mapped to the parameters of an Ising-like model and bystander interactions are introduced as a short-range interaction as is the case for the Ising model. As an example, we apply the model to study the effect of bystander interactions in the case of radiation therapy for prostate cancer. The model shows that it is adequate to neglect bystander interactions for dose distributions that completely cover the treatment target and yield TCP estimates that lie in the shoulder of the dose response curve. However, for dose distributions that yield TCP estimates that lie on the steep part of the dose response curve or for inhomogeneous dose distributions having significant hot and/or cold regions, bystander effects may be important. Furthermore, the proposed model highlights a previously unexplored and potentially fruitful connection between the fields of statistical mechanics and tumor control probability/normal tissue complication probability modeling.

Boron Neutron Capture Therapy (BCNT) for the Treatment of Liver Metastases: Biodistribution Studies of Boron Compounds in an Experimental Model

Energy Technology Data Exchange (ETDEWEB)

Marcela A. Garabalino; Andrea Monti Hughes; Ana J. Molinari; Elisa M. Heber; Emiliano C. C. Pozzi; Maria E. Itoiz; Veronica A. Trivillin; Amanda E. Schwint; Jorge E. Cardoso; Lucas L. Colombo; Susana Nievas; David W. Nigg; Romina F. Aromando

2011-03-01

Abstract We previously demonstrated the therapeutic efficacy of different boron neutron capture therapy (BNCT) protocols in an experimental model of oral cancer. BNCT is based on the selective accumulation of 10B carriers in a tumor followed by neutron irradiation. Within the context of exploring the potential therapeutic efficacy of BNCT for the treatment of liver metastases, the aim of the present study was to perform boron biodistribution studies in an experimental model of liver metastases in rats. Different boron compounds and administration conditions were assayed to determine which administration protocols would potentially be therapeutically useful in in vivo BNCT studies at the RA-3 nuclear reactor. A total of 70 BDIX rats were inoculated in the liver with syngeneic colon cancer cells DHD/K12/TRb to induce the development of subcapsular tumor nodules. Fourteen days post-inoculation, the animals were used for biodistribution studies. We evaluated a total of 11 administration protocols for the boron compounds boronophenylalanine (BPA) and GB-10 (Na210B10H10), alone or combined at different dose levels and employing different administration routes. Tumor, normal tissue, and blood samples were processed for boron measurement by atomic emission spectroscopy. Six protocols proved potentially useful for BNCT studies in terms of absolute boron concentration in tumor and preferential uptake of boron by tumor tissue. Boron concentration values in tumor and normal tissues in the liver metastases model show it would be feasible to reach therapeutic BNCT doses in tumor without exceeding radiotolerance in normal tissue at the thermal neutron facility at RA-3.

Mouse Models Recapitulating Human Adrenocortical Tumors: What is lacking?

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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.

Emergent Stratification in Solid Tumors Selects for Reduced Cohesion of Tumor Cells: A Multi-Cell, Virtual-Tissue Model of Tumor Evolution Using CompuCell3D.

Directory of Open Access Journals (Sweden)

Maciej H Swat

Full Text Available Tumor cells and structure both evolve due to heritable variation of cell behaviors and selection over periods of weeks to years (somatic evolution. Micro-environmental factors exert selection pressures on tumor-cell behaviors, which influence both the rate and direction of evolution of specific behaviors, especially the development of tumor-cell aggression and resistance to chemotherapies. In this paper, we present, step-by-step, the development of a multi-cell, virtual-tissue model of tumor somatic evolution, simulated using the open-source CompuCell3D modeling environment. Our model includes essential cell behaviors, microenvironmental components and their interactions. Our model provides a platform for exploring selection pressures leading to the evolution of tumor-cell aggression, showing that emergent stratification into regions with different cell survival rates drives the evolution of less cohesive cells with lower levels of cadherins and higher levels of integrins. Such reduced cohesivity is a key hallmark in the progression of many types of solid tumors.

Endoscopic Cerenkov luminescence imaging: in vivo small animal tumor model validation

Science.gov (United States)

Song, Tianming; Bao, Chengpeng; Hu, Zhenhua; Wang, Kun; Liu, Xia; Tian, Jie

2015-03-01

Background: Cerenkov luminescence imaging (CLI) provides a great potential for clinical translation of optical molecular imaging techniques through using clinical approved radiotracers. However, it is difficult to obtain the Cerenkov luminescence signal of deeper biological tissues due to the small magnitude of the signal. To efficiently acquire the weak Cerenkov luminescence, we developed an endoscopic Cerenkov luminescence imaging (ECLI) system to reduce the in vivo imaging depth with minimum invasion, and validated the system on small animal tumor models. Methods: For the ECLI system, the laparoscope was connected to a high sensitive charge-couple device (CCD) camera (DU888+, Andor, UK) by a custom made adapter. We conducted a series of in vitro and in vivo experiments by use of the system. In the in vitro experiment, the endoscopic luminescence images of the 18F-FDG with various activities in EP tubes were acquired using ECLI system, and the sensitivity was compared with conventional CLI system. In the in vivo tumor experiment, 18F-FDG with the activity of 200μCi were intravenously injected into 3 tumor mice. Then the ECLI system was used to acquire the optical images for both non-invasive and invasive conditions. Conclusion: Experimental data showed the ECLI system could detect the 18F-FDG with the activity as low as 1μCi. Furthermore, our preliminary results indicated the possibility of ECLI technique for detecting Cerenkov signals inside the tumor tissue with deeper depth and guiding the surgical operation of tumor excision. We believe that this technique can help to accelerate the clinical translation of CLI.

Radio-frequency ablation in patients with malignant hepatic tumor and experimental model: comparison of expandable needle and water-cooled needle

Energy Technology Data Exchange (ETDEWEB)

Moon, Yong Ju; Jeong, Yong Yeon; Kim, Jeong; Yim, Nam yeol; Kang, Heoung Keun [School of Medicine, Chonnam National Univ., Gwangju (Korea, Republic of); Kim, Eun Ha; Yoon, Kwon Ha [School of Medicine, Wonkwang Univ., Iksan (Korea, Republic of); Ko, Seog Wan [School of Medicine, Chonbuk National Univ., Jeonju (Korea, Republic of)

2004-12-01

The purpose of this study was to compare the shape and volume of the radio-frequency induced lesions produced by two commercially available radio-frequency ablation (RFA) systems, the expandable and cooled-tip needles, in clinical patients and an experimental model. A twelve-array anchor expandable needle electrode and a single cooled-tip needle electrode were used to treat hepatic tumors with a single session in 23 patients (20 hepatocellular carcinomas and 3 hepatic metastases) and fourteen patients (10 hepatocellular carcinomas and 4 hepatic metastases), respectively. Twenty RFA induced lesions were created with each system in 10 explanted bovine livers. The shape of the RFA induced lesions were divided into oval lesions along or perpendicular to the axis of the electrode and spherical lesions, and we then calculated the volumes of the RFA induced lesions. Fourteen (61%) lesions of the 23 patients treated with the expandable system were oval perpendicular to the axis of the electrode and nine (39%) of the lesions were spherical. All the lesions (100%) of the 14 patients treated with the cooled-tip needle were ovaI along the axis of the electrode. In the ex vivo bovine livers, the shape of the all RFA induced lesions was oval perpendicular to the axis of the electrode for the expandable needle, and oval along the axis of the electrode for the cooled-tip needle. The mean diameter and volume of the RFA induced lesions in the patients were 3.35{+-}0.56 cm and 19.9{+-}6.53 cm{sup 3}, respectively, for the expandable needle and 3.58{+-}0.78 cm and 23.19{+-}5.27 cm{sup 3}, respectively, for the cooled-tip needle. In the ex vivo model, the mean diameter and volume of RFA induced lesions were 3.41{+-}0.59 cm and 26.59{+-}8.02 cm{sup 3}, respectively, for the expandable needle, and 4.04{+-}0.65 cm and 33.82{+-}6.16 cm{sup 3}, respectively, for the cooled-tip needle (p <0.05). These results indicate that the shape of RFA induced lesions with the expandable needle were oval

Effect of interventional treatment with p53 on the invasion and metastasis of VX2 liver tumor in experimental rabbits

International Nuclear Information System (INIS)

Li Caixia; Feng Yan; Gu Tao; Li Chunmei

2010-01-01

Objective: To investigate the effect of interventional treatment with p53 on the invasion and metastasis of VX2 liver tumor in experimental rabbits. Methods: VX2 carcinoma cells were surgically implanted into the left hepatic lobe in 48 New Zealand white rabbits, and the rabbit hepatic carcinoma models were thus established. The rabbits were randomly divided into 4 groups with 12 rabbits in each group. After hepatic arterial catheterization was completed physiological saline (control group), Lipiodol (Group A), Ad-p53 (Group B) and Lipiodol+Ad-p53 (Group C) were respectively infused into the rabbits of four groups via common hepatic artery. One week after the procedure the rabbits were sacrificed and the livers were removed for the determination of matrix metalloprotein-2 (MMP-2), proliferating cell nuclear antigen (PCNA) and vascular endothelial growth factor (VEGF) of the tumor with immunohistochemistry technique. Results: The tumor growth in study groups (group A, B and C) was markedly suppressed, which was significantly different in comparison with that in control group (P 0.05). The positive rates of MMP-2, PCNA and VEGF in group B and C were significantly lower than those in control group (P < 0.05). The positive rates of MMP-2, PCNA and VEGF of the rabbits with metastasis were markedly higher than those without metastasis(P < 0.05). MMP-2 bore a certain relationship with VEGF and PCNA (P < 0.05). Conclusion: The increase of the positive rates of MMP-2, PCNA and VEGF indicates that the tumor possesses higher possibility for developing metastasis, proliferation and vascular formation. The interventional treatment with Adp53 or Lipiodol+Ad-p53 can inhibit the growth, metastasis and vascular formation of VX2 liver tumor in experimental rabbits. (J Intervent Radiol, 2010, 19 : 800-804) (authors)

Hedgehog pathway activity in the LADY prostate tumor model

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Kasper Susan

2007-03-01

Full Text Available Abstract Background Robust Hedgehog (Hh signaling has been implicated as a common feature of human prostate cancer and an important stimulus of tumor growth. The role of Hh signaling has been studied in several xenograft tumor models, however, the role of Hh in tumor development in a transgenic prostate cancer model has never been examined. Results We analyzed expression of Hh pathway components and conserved Hh target genes along with progenitor cell markers and selected markers of epithelial differentiation during tumor development in the LADY transgenic mouse model. Tumor development was associated with a selective increase in Ihh expression. In contrast Shh expression was decreased. Expression of the Hh target Patched (Ptc was significantly decreased while Gli1 expression was not significantly altered. A survey of other relevant genes revealed significant increases in expression of Notch-1 and Nestin together with decreased expression of HNF3a/FoxA1, NPDC-1 and probasin. Conclusion Our study shows no evidence for a generalized increase in Hh signaling during tumor development in the LADY mouse. It does reveal a selective increase in Ihh expression that is associated with increased expression of progenitor cell markers and decreased expression of terminal differentiation markers. These data suggest that Ihh expression may be a feature of a progenitor cell population that is involved in tumor development.

Causation of nervous system tumors in children: insights from traditional and genetically engineered animal models

International Nuclear Information System (INIS)

Rice, Jerry M.

2004-01-01

Pediatric neurogenic tumors include primitive neuroectodermal tumors (PNETs), especially medulloblastoma; ependymomas and choroid plexus papillomas; astrocytomas; retinoblastoma; and sympathetic neuroblastoma. Meningiomas and nerve sheath tumors, although uncommon in childhood, are also significant because they can result from exposures of children to ionizing radiation. Specific chromosomal loci and specific genes are related to each of these tumor types. Virtually all these genes appear to act as tumor suppressor genes, which are inactivated in tumor cells by mutations or by chromosomal loss. In genetically engineered mice, some genes that are clearly associated with specific human tumors (e.g., RB1 in retinoblastoma and NF2 in meningiomas and schwannomas) have no such effect. Other genetic constructs in mice involving the genes p53, ptc1, and Nf1 have produced tumors remarkably similar to some of the human pediatric neoplasms. Some of these tumors become clinically apparent after only a few weeks, while the mice are still juveniles, especially when two or more tumor suppressor genes are inactivated in the same genetic construct. Conversely, at least one genetic pathway in rodents involving point mutation in the coding region of a transforming gene (neu in malignant schwannomas) does not appear to operate in any human tumors. The nervous system is markedly susceptible to experimental carcinogenesis during early life in rodents, dogs, primates, and other nonhuman species, and there is no obvious reason why this generalization should not also apply to humans. However, except for therapeutic ionizing radiation, no physical, chemical, or biological cause of human pediatric nervous system tumors is known. The failure of experimental transplacental carcinogenesis to mirror human pediatric experience more closely may reflect the need for multiple mutational events in target cells, and for experimental carcinogens that are capable of causing the full spectrum of

In Vitro Tumor Models: Advantages, Disadvantages, Variables, and Selecting the Right Platform.

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Katt, Moriah E; Placone, Amanda L; Wong, Andrew D; Xu, Zinnia S; Searson, Peter C

2016-01-01

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 toward 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.

A murine model of targeted infusion for intracranial tumors.

Science.gov (United States)

Kim, Minhyung; Barone, Tara A; Fedtsova, Natalia; Gleiberman, Anatoli; Wilfong, Chandler D; Alosi, Julie A; Plunkett, Robert J; Gudkov, Andrei; Skitzki, Joseph J

2016-01-01

Historically, intra-arterial (IA) drug administration for malignant brain tumors including glioblastoma multiforme (GBM) was performed as an attempt to improve drug delivery. With the advent of percutaneous neuorovascular techniques and modern microcatheters, intracranial drug delivery is readily feasible; however, the question remains whether IA administration is safe and more effective compared to other delivery modalities such as intravenous (IV) or oral administrations. Preclinical large animal models allow for comparisons between treatment routes and to test novel agents, but can be expensive and difficult to generate large numbers and rapid results. Accordingly, we developed a murine model of IA drug delivery for GBM that is reproducible with clear readouts of tumor response and neurotoxicities. Herein, we describe a novel mouse model of IA drug delivery accessing the internal carotid artery to treat ipsilateral implanted GBM tumors that is consistent and reproducible with minimal experience. The intent of establishing this unique platform is to efficiently interrogate targeted anti-tumor agents that may be designed to take advantage of a directed, regional therapy approach for brain tumors.

Inference of Tumor Evolution during Chemotherapy by Computational Modeling and In Situ Analysis of Genetic and Phenotypic Cellular Diversity

Directory of Open Access Journals (Sweden)

Vanessa Almendro

2014-02-01

Full Text Available Cancer therapy exerts a strong selection pressure that shapes tumor evolution, yet our knowledge of how tumors change during treatment is limited. Here, we report the analysis of cellular heterogeneity for genetic and phenotypic features and their spatial distribution in breast tumors pre- and post-neoadjuvant chemotherapy. We found that intratumor genetic diversity was tumor-subtype specific, and it did not change during treatment in tumors with partial or no response. However, lower pretreatment genetic diversity was significantly associated with pathologic complete response. In contrast, phenotypic diversity was different between pre- and posttreatment samples. We also observed significant changes in the spatial distribution of cells with distinct genetic and phenotypic features. We used these experimental data to develop a stochastic computational model to infer tumor growth patterns and evolutionary dynamics. Our results highlight the importance of integrated analysis of genotypes and phenotypes of single cells in intact tissues to predict tumor evolution.

Inference of tumor evolution during chemotherapy by computational modeling and in situ analysis of genetic and phenotypic cellular diversity

International Nuclear Information System (INIS)

Almendro, Vanessa; Cheng, Yu-Kang; Randles, Amanda; Itzkovitz, Shalev; Marusyk, Andriy; Ametller, Elisabet; Gonzalez-Farre, Xavier; Muñoz, Montse; Russnes, Hege G.; Helland, Åslaug; Rye, Inga H.; Borresen-Dale, Anne-Lise; Maruyama, Reo; Van Oudenaarden, Alexander; Dowsett, Mitchell; Jones, Robin L.; Reis-Filho, Jorge; Gascon, Pere; Gönen, Mithat; Michor, Franziska; Polyak, Kornelia

2014-01-01

Cancer therapy exerts a strong selection pressure that shapes tumor evolution, yet our knowledge of how tumors change during treatment is limited. Here, we report the analysis of cellular heterogeneity for genetic and phenotypic features and their spatial distribution in breast tumors pre- and post-neoadjuvant chemotherapy. We found that intratumor genetic diversity was tumor-subtype specific, and it did not change during treatment in tumors with partial or no response. However, lower pretreatment genetic diversity was significantly associated with pathologic complete response. In contrast, phenotypic diversity was different between pre- and post-treatment samples. We also observed significant changes in the spatial distribution of cells with distinct genetic and phenotypic features. We used these experimental data to develop a stochastic computational model to infer tumor growth patterns and evolutionary dynamics. Our results highlight the importance of integrated analysis of genotypes and phenotypes of single cells in intact tissues to predict tumor evolution

Experimental evaluation of analytical penumbra calculation model for wobbled beams

International Nuclear Information System (INIS)

Kohno, Ryosuke; Kanematsu, Nobuyuki; Yusa, Ken; Kanai, Tatsuaki

2004-01-01

The goal of radiotherapy is not only to apply a high radiation dose to a tumor, but also to avoid side effects in the surrounding healthy tissue. Therefore, it is important for carbon-ion treatment planning to calculate accurately the effects of the lateral penumbra. In this article, for wobbled beams under various irradiation conditions, we focus on the lateral penumbras at several aperture positions of one side leaf of the multileaf collimator. The penumbras predicted by an analytical penumbra calculation model were compared with the measured results. The results calculated by the model for various conditions agreed well with the experimental ones. In conclusion, we found that the analytical penumbra calculation model could predict accurately the measured results for wobbled beams and it was useful for carbon-ion treatment planning to apply the model

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.

The histopathology of a human mesenchymal stem cell experimental tumor model: support for an hMSC origin for Ewing's sarcoma?

DEFF Research Database (Denmark)

Burns, J S; Abdallah, B M; Schrøder, Henrik Daa

2008-01-01

-forming potential of early passage hMSC-TERT20 cells, tumors derived from late passage cells expressed early biomarkers of osteogenesis. However, hMSC-TERT20 cells were heterogeneous for alpha smooth muscle actin (ASMA) expression and one out of six hMSC-TERT20 derived single cell clones was strongly ASMA positive....... Tumors from this ASMA+ clone had distinctive vascular qualities with hot spots of high CD34+ murine endothelial cell density, together with CD34- regions with a branching periodic acid Schiff reaction pattern. Such clone-specific differences in host vascular response provide novel models to explore...

Immunotherapy in mice of virally induced tumors using syngeneic monoclonal antibodies

NARCIS (Netherlands)

D. Berends (Derk)

1988-01-01

textabstractThis thesis deals with one variant of immunotherapy, namely the use of tumor-specific antibodies to induce tumor destruction. The experimental work falls apart into four succeeding phases: a) definition of the model, which means the choice of the animal and the tumor, the generation

Localization of the experimental tumor regrowth after irradiation

Energy Technology Data Exchange (ETDEWEB)

Yamaura, H; Matsuzawa, T [Tohoku Univ., Sendai (Japan). Research Inst. for Tuberculosis and Cancer

1978-08-01

The process of the structural changes in the irradiated AH109A tumor and its regrowth was studied, using histologic and transparent-chamber techniques. The tumor tissue was divided into four successive layers, according to vascular morphology and measures. The vascularity was the greatest in the outermost region and decreased towards the inner part of the tumor until necrosis. The tumor was irradiated with various doses of x and gamma-rays. The inside hypoxic region was destroyed completely after 3,000 rad and regrowths started from the outermost area of the tumor where oxygen enhancing effect to irradiation was supposed to be the greatest.

Dynamic 11C-methionine PET analysis has an additional value for differentiating malignant tumors from granulomas: an experimental study using small animal PET

International Nuclear Information System (INIS)

Zhao, Songji; Zhao, Yan; Kuge, Yuji; Hatano, Toshiyuki; Yi, Min; Kohanawa, Masashi; Magota, Keiichi; Tamaki, Nagara; Nishijima, Ken-ichi

2011-01-01

We evaluated whether the dynamic profile of L- 11 C-methionine ( 11 C-MET) may have an additional value in differentiating malignant tumors from granulomas in experimental rat models by small animal positron emission tomography (PET). Rhodococcus aurantiacus and allogenic rat C6 glioma cells were inoculated, respectively, into the right and left calf muscles to generate a rat model bearing both granulomas and tumors (n = 6). Ten days after the inoculations, dynamic 11 C-MET PET was performed by small animal PET up to 120 min after injection of 11 C-MET. The next day, after overnight fasting, the rats were injected with 18 F-2-deoxy-2-fluoro-D-glucose ( 18 F-FDG), and dynamic 18 F-FDG PET was performed up to 180 min. The time-activity curves, static images, and mean standardized uptake value (SUV) in the lesions were calculated. 11 C-MET uptake in the granuloma showed a slow exponential clearance after an initial distribution, while the uptake in the tumor gradually increased with time. The dynamic pattern of 11 C-MET uptake in the granuloma was significantly different from that in the tumor (p 11 C-MET, visual assessment and SUV analysis could not differentiate the tumor from the granuloma in all cases, although the mean SUV in the granuloma (1.48 ± 0.09) was significantly lower than that in the tumor (1.72 ± 0.18, p 18 F-FDG in the granuloma were similar to those in the tumor (p = NS). Dynamic 11 C-MET PET has an additional value for differentiating malignant tumors from granulomatous lesions, which deserves further elucidation in clinical settings. (orig.)

Incorporation of diffusion-weighted magnetic resonance imaging data into a simple mathematical model of tumor growth

International Nuclear Information System (INIS)

Atuegwu, N C; Colvin, D C; Loveless, M E; Gore, J C; Yankeelov, T E; Xu, L

2012-01-01

We build on previous work to show how serial diffusion-weighted MRI (DW-MRI) data can be used to estimate proliferation rates in a rat model of brain cancer. Thirteen rats were inoculated intracranially with 9L tumor cells; eight rats were treated with the chemotherapeutic drug 1,3-bis(2-chloroethyl)-1-nitrosourea and five rats were untreated controls. All animals underwent DW-MRI immediately before, one day and three days after treatment. Values of the apparent diffusion coefficient (ADC) were calculated from the DW-MRI data and then used to estimate the number of cells in each voxel and also for whole tumor regions of interest. The data from the first two imaging time points were then used to estimate the proliferation rate of each tumor. The proliferation rates were used to predict the number of tumor cells at day three, and this was correlated with the corresponding experimental data. The voxel-by-voxel analysis yielded Pearson's correlation coefficients ranging from −0.06 to 0.65, whereas the region of interest analysis provided Pearson's and concordance correlation coefficients of 0.88 and 0.80, respectively. Additionally, the ratio of positive to negative proliferation values was used to separate the treated and control animals (p <0.05) at an earlier point than the mean ADC values. These results further illustrate how quantitative measurements of tumor state obtained non-invasively by imaging can be incorporated into mathematical models that predict tumor growth. (paper)

Biochemomechanical poroelastic theory of avascular tumor growth

Science.gov (United States)

Xue, Shi-Lei; Li, Bo; Feng, Xi-Qiao; Gao, Huajian

2016-09-01

Tumor growth is a complex process involving genetic mutations, biochemical regulations, and mechanical deformations. In this paper, a thermodynamics-based nonlinear poroelastic theory is established to model the coupling among the mechanical, chemical, and biological mechanisms governing avascular tumor growth. A volumetric growth law accounting for mechano-chemo-biological coupled effects is proposed to describe the development of solid tumors. The regulating roles of stresses and nutrient transport in the tumor growth are revealed under different environmental constraints. We show that the mechano-chemo-biological coupling triggers anisotropic and heterogeneous growth, leading to the formation of layered structures in a growing tumor. There exists a steady state in which tumor growth is balanced by resorption. The influence of external confinements on tumor growth is also examined. A phase diagram is constructed to illustrate how the elastic modulus and thickness of the confinements jointly dictate the steady state of tumor volume. Qualitative and quantitative agreements with experimental observations indicate the developed model is capable of capturing the essential features of avascular tumor growth in various environments.

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

Radiosensitizing effect of nitric oxide in tumor cells and experimental tumors irradiated with gamma rays and proton beams; Efecto radiosensibilizador del oxido nitrico en celulas tumorales y en tumores experimentales irradiados con radiacion gamma y con haces de protones

Energy Technology Data Exchange (ETDEWEB)

Policastro, Lucia L; Duran, Hebe; Molinari, Beatriz L [Comision Nacional de Energia Atomica, General San Martin (Argentina). Dept. de Radiobiologia; Schuff, Juan A; Kreiner, Andres J; Burlon, Alejandro A; Debray, Mario E; Kesque, Jose M; Ozafran, Mabel J; Vazquez, Monica E [Comision Nacional de Energia Atomica, General San Martin (Argentina). Dept. de Fisica; Davidson, Jorge; Davidson, Miguel [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Buenos Aires (Argentina); Somacal, Hector R; Valda, Alejandro A [Universidad Nacional de General San Martin , Villa Ballester (Argentina). Escuela de Ciencia y Tecnologia

2003-07-01

Nitric oxide (NO) has been reported to be a radiosensitizer of mammalian cells under hypoxic conditions. In a previous study, we demonstrated an enhancement in radiation response induced by NO in mouse tumor cells under aerobic conditions, with an increasing effect as a function of malignancy. The aim of the present study was to evaluate the effect of NO in tumor cells and in experimental tumors irradiated with {gamma} rays and proton beams. Irradiations were performed with a {sup 137}Cs {gamma} source and with proton beams generated by the TANDAR accelerator. Tumor cells were treated with the NO donor DETA-NO and the sensitizer enhancement ratio (SER) was calculated using the {alpha} parameter of the survival curve fitted to the linear-quadratic model. Tumor cells irradiated with protons were radio sensitized by DETA-NO only in the more malignant cells irradiated with low LET protons (2.69{+-}0.08 keV/{mu}m). For higher LET protons there were no radiosensitizing effect. For human tumor cells pre-treated with DETA-NO and irradiated with {gamma} rays, a significantly greater effect was demonstrated in the malignant cells (MCF-7) as compared with the near normal cells (HBL-100). Moreover, a significant decrease in tumor growth was demonstrated in mice pre-treated with the NO donor spermine and irradiated with {gamma} rays and low LET protons as compared with mice irradiated without pre-treatment with the NO donor. In conclusion, we demonstrated a differential effect of NO as a radiosensitizer of malignant cells, both with {gamma} rays and low LET protons. This selectivity, coupled to the in vivo inhibition of tumor growth, is of great interest for the potential use of NO releasing agents in radiotherapy. (author)

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  < 0.0001) in the high-grade ( D fm : 0.81 ± 0.26, φ : 1.40 ± 0.10, ψ : 0.42 ± 0.11) than in the low-grade ( D fm : 1.52 ± 0.52, φ : 1.64 ± 0.13, ψ : 0.67 ± 0.13) tumor groups. The ROC analysis showed that the FM parameters offered better specificity (88% versus 73%), sensitivity (90% versus 82%), accuracy (88% versus 78%), and area under the curve (AUC, 93% versus 80%) in discriminating tumor malignancy compared to the conventional ADC. The performance of the FM model was similar to that of the CTRW model. Similar to the CTRW model, the FM model can improve differentiation between low- and high-grade pediatric brain tumors over ADC.

Extravascular transport in normal and tumor tissues.

Science.gov (United States)

Jain, R K; Gerlowski, L E

1986-01-01

The transport characteristics of the normal and tumor tissue extravascular space provide the basis for the determination of the optimal dosage and schedule regimes of various pharmacological agents in detection and treatment of cancer. In order for the drug to reach the cellular space where most therapeutic action takes place, several transport steps must first occur: (1) tissue perfusion; (2) permeation across the capillary wall; (3) transport through interstitial space; and (4) transport across the cell membrane. Any of these steps including intracellular events such as metabolism can be the rate-limiting step to uptake of the drug, and these rate-limiting steps may be different in normal and tumor tissues. This review examines these transport limitations, first from an experimental point of view and then from a modeling point of view. Various types of experimental tumor models which have been used in animals to represent human tumors are discussed. Then, mathematical models of extravascular transport are discussed from the prespective of two approaches: compartmental and distributed. Compartmental models lump one or more sections of a tissue or body into a "compartment" to describe the time course of disposition of a substance. These models contain "effective" parameters which represent the entire compartment. Distributed models consider the structural and morphological aspects of the tissue to determine the transport properties of that tissue. These distributed models describe both the temporal and spatial distribution of a substance in tissues. Each of these modeling techniques is described in detail with applications for cancer detection and treatment in mind.

Radiographically determined growth kinetics of primary lung tumors in the dog

International Nuclear Information System (INIS)

Perry, R.E.; Weller, R.E.; Buschbom, R.L.; Dagle, G.E.; Park, J.F.

1989-10-01

Tumor growth rate patterns especially tumor doubling time (TDT), have been extensively evaluated in man. Studies involving the determination of TDT in humans are limited, however, by the number of cases, time consistent radiographic tumor measurements, and inability to perform experimental procedures. In animals similar constraints do not exist. Lifespan animal models lend themselves well to tumor growth pattern analysis. Experimental studies have been designed to evaluate both the biological effects and growth patterns of induced and spontaneous tumors. The purpose of this study was to calculate the tumor volume doubling times (TCDT) for radiation-induced and spontaneous primary pulmonary neoplasms in dogs to see if differences existed due to etiology, sex or histologic cell type, and to determine if the time of tumor onset could be extrapolated from the TVDT. 3 refs

PDX-MI: Minimal Information for Patient-Derived Tumor Xenograft Models

NARCIS (Netherlands)

Meehan, Terrence F.; Conte, Nathalie; Goldstein, Theodore; Inghirami, Giorgio; Murakami, Mark A.; Brabetz, Sebastian; Gu, Zhiping; Wiser, Jeffrey A.; Dunn, Patrick; Begley, Dale A.; Krupke, Debra M.; Bertotti, Andrea; Bruna, Alejandra; Brush, Matthew H.; Byrne, Annette T.; Caldas, Carlos; Christie, Amanda L.; Clark, Dominic A.; Dowst, Heidi; Dry, Jonathan R.; Doroshow, James H.; Duchamp, Olivier; Evrard, Yvonne A.; Ferretti, Stephane; Frese, Kristopher K.; Goodwin, Neal C.; Greenawalt, Danielle; Haendel, Melissa A.; Hermans, Els; Houghton, Peter J.; Jonkers, Jos; Kemper, Kristel; Khor, Tin O.; Lewis, Michael T.; Lloyd, K. C. Kent; Mason, Jeremy; Medico, Enzo; Neuhauser, Steven B.; Olson, James M.; Peeper, Daniel S.; Rueda, Oscar M.; Seong, Je Kyung; Trusolino, Livio; Vinolo, Emilie; Wechsler-Reya, Robert J.; Weinstock, David M.; Welm, Alana; Weroha, S. John; Amant, Frédéric; Pfister, Stefan M.; Kool, Marcel; Parkinson, Helen; Butte, Atul J.; Bult, Carol J.

2017-01-01

Patient-derived tumor xenograft (PDX) mouse models have emerged as an important oncology research platform to study tumor evolution, mechanisms of drug response and resistance, and tailoring chemotherapeutic approaches for individual patients. The lack of robust standards for reporting on PDX models

Boron Neutron Capture Therapy (BNCT) in an experimental model of lung metastases in BDIX rats

International Nuclear Information System (INIS)

Trivillin, V.A.; Garabalino, M.A.; Colombo, L.L.

2013-01-01

Boron Neutron Capture Therapy (BNCT) in an experimental model of lung metastases in BDIX rats Introduction: Boron Neutron Capture Therapy (BNCT) is based on selective tumor uptake of boron compounds, followed by neutron irradiation. BNCT was proposed for the treatment of unresectable, diffuse lung metastases. The aim of the present study was to perform BNCT studies in an experimental model of lung metastases. Materials and Methods: 3 x 106/0.5 ml colon carcinoma cells (DHD/K12/TRb) were injected iv in syngeneic BDIX rats. Three weeks post-inoculation, rats with diffuse lung metastases were used for in vivo BNCT studies in the RA-3 Nuclear Reactor. Based on previous biodistribution studies and computational dosimetry with Monte Carlo simulation, 2 doses were prescribed, i.e. 4 Gy and 8 Gy minimum absorbed dose to tumor. The animals were assigned to 5 experimental groups (n= 4 to 8) at each dose level: T0 (euthanized pre-treatment), BPA-BNCT, Comb-BNCT (BPA+GB-10), Beam only (background dose) and Sham (same manipulation, no treatment). Boron concentration was measured in a blood sample taken pre-irradiation to verify that the value was in the range established in previous biodistribution studies. The animals were followed clinically for 2 weeks after neutron irradiation and then euthanized to assess the response of tumor and normal lung, macroscopically and histologically. To date we have evaluated the end-point weight of lung (normal lung + metastases) and % lung weight/body weight as an indicator of tumor growth. Results: The statistical analysis (ANOVA) of % lung weight/body weight showed statistically significant differences (p<0.05) between groups T0 (0.79 ± 0.38) and Sham (1.87 ± 0.91). No statistically significant differences were observed between the Beam only groups (at both dose levels) and Sham. Similar and statistically significant tumor control was induced in the groups BPA-BNCT Low dose (LD) (0.56 ± 0.11), BPA-BNCT High dose (HD) (0.80 ± 0.16), Comb

Bifurcation analysis of a delayed mathematical model for tumor growth

International Nuclear Information System (INIS)

Khajanchi, Subhas

2015-01-01

In this study, we present a modified mathematical model of tumor growth by introducing discrete time delay in interaction terms. The model describes the interaction between tumor cells, healthy tissue cells (host cells) and immune effector cells. The goal of this study is to obtain a better compatibility with reality for which we introduced the discrete time delay in the interaction between tumor cells and host cells. We investigate the local stability of the non-negative equilibria and the existence of Hopf-bifurcation by considering the discrete time delay as a bifurcation parameter. We estimate the length of delay to preserve the stability of bifurcating periodic solutions, which gives an idea about the mode of action for controlling oscillations in the tumor growth. Numerical simulations of the model confirm the analytical findings

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

end, due to anoxia, but smaller tumors showed undisturbed oxygen distributions. The six different models with correlated parameters generated three classes of oxygen distributions. The first was a hypothetical, negative covariance between vessel proximity and pO 2 (VPO-C scenario); the second was a hypothetical positive covariance between vessel proximity and pO 2 (VPO+C scenario); and the third was the hypothesis of no correlation between vessel proximity and pO 2 (UP scenario). The VPO-C scenario produced a distinctly different oxygen distribution than the two other scenarios. The shape of the VPO-C scenario was similar to that of the nonvariable DOC model, and the larger the tumor, the greater the similarity between the two models. For all simulations, the mean oxygen tension decreased and the hypoxic fraction increased with tumor size. The absorbed dose required for definitive tumor control was highest for the VPO+C scenario, followed by the UP and VPO-C scenarios. Conclusions: A novel MC algorithm was presented which simulated oxygen distributions and radiation response for various biological parameter values. The analysis showed that the VPO-C scenario generated a clearly different oxygen distribution from the VPO+C scenario; the former exhibited a lower hypoxic fraction and higher radiosensitivity. In future studies, this modeling approach might be valuable for qualitative analyses of factors that affect oxygen distribution as well as analyses of specific experimental and clinical situations

Detection limits of intraoperative near infrared imaging for tumor resection.

Science.gov (United States)

Thurber, Greg M; Figueiredo, Jose-Luiz; Weissleder, Ralph

2010-12-01

The application of fluorescent molecular imaging to surgical oncology is a developing field with the potential to reduce morbidity and mortality. However, the detection thresholds and other requirements for successful intervention remain poorly understood. Here we modeled and experimentally validated depth and size of detection of tumor deposits, trade-offs in coverage and resolution of areas of interest, and required pharmacokinetics of probes based on differing levels of tumor target presentation. Three orthotopic tumor models were imaged by widefield epifluorescence and confocal microscopes, and the experimental results were compared with pharmacokinetic models and light scattering simulations to determine detection thresholds. Widefield epifluorescence imaging can provide sufficient contrast to visualize tumor margins and detect tumor deposits 3-5  mm deep based on labeled monoclonal antibodies at low objective magnification. At higher magnification, surface tumor deposits at cellular resolution are detectable at TBR ratios achieved with highly expressed antigens. A widefield illumination system with the capability for macroscopic surveying and microscopic imaging provides the greatest utility for varying surgical goals. These results have implications for system and agent designs, which ultimately should aid complete resection in most surgical beds and provide real-time feedback to obtain clean margins. © 2010 Wiley-Liss, Inc.

Multimodality Tumor Delineation and Predictive Modelling via Fuzzy-Fusion Deformable Models and Biological Potential Functions

Science.gov (United States)

Wasserman, Richard Marc

The radiation therapy treatment planning (RTTP) process may be subdivided into three planning stages: gross tumor delineation, clinical target delineation, and modality dependent target definition. The research presented will focus on the first two planning tasks. A gross tumor target delineation methodology is proposed which focuses on the integration of MRI, CT, and PET imaging data towards the generation of a mathematically optimal tumor boundary. The solution to this problem is formulated within a framework integrating concepts from the fields of deformable modelling, region growing, fuzzy logic, and data fusion. The resulting fuzzy fusion algorithm can integrate both edge and region information from multiple medical modalities to delineate optimal regions of pathological tissue content. The subclinical boundaries of an infiltrating neoplasm cannot be determined explicitly via traditional imaging methods and are often defined to extend a fixed distance from the gross tumor boundary. In order to improve the clinical target definition process an estimation technique is proposed via which tumor growth may be modelled and subclinical growth predicted. An in vivo, macroscopic primary brain tumor growth model is presented, which may be fit to each patient undergoing treatment, allowing for the prediction of future growth and consequently the ability to estimate subclinical local invasion. Additionally, the patient specific in vivo tumor model will be of significant utility in multiple diagnostic clinical applications.

Tumor control induced by Boron Neutron Capture Therapy (BNCT) as a function of dose in an experimental model of liver metastases at 5 weeks follow-up

International Nuclear Information System (INIS)

Pozzi, E C C; Trivillin, V A; Colombo, L L; Monti Hughes, A; Thorp, S; Cardoso, J E; Garabalino, M A; Molinari, A J; Heber, E M; Curotto, Paula; Miller, M; Itoiz, M E; Aromando, R F; Nigg, D W; Schwint, A E

2012-01-01

BNCT has been proposed for the treatment of multifocal, non-resectable, bilobar colorectal liver metastases that do not respond to chemotherapy. We recently reported that BNCT mediated by boronophenylalanine (BPA) induced significant remission of experimental colorectal tumor nodules in rat liver at 3 weeks follow-up with no contributory liver toxicity (Pozzi et al.,2012). The aim of the present study was to evaluate tumor control and potential liver toxicity of BPA-BNCT at 5 weeks follow-up. Prescribed dose was retrospectively evaluated based on blood boron values, allowing for assessment of response over a range of delivered dose values (author)

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.

New experimental model of multiple myeloma.

Science.gov (United States)

Telegin, G B; Kalinina, A R; Ponomarenko, N A; Ovsepyan, A A; Smirnov, S V; Tsybenko, V V; Homeriki, S G

2001-06-01

NSO/1 (P3x63Ay 8Ut) and SP20 myeloma cells were inoculated to BALB/c OlaHsd mice. NSO/1 cells allowed adequate stage-by-stage monitoring of tumor development. The adequacy of this model was confirmed in experiments with conventional cytostatics: prospidium and cytarabine caused necrosis of tumor cells and reduced animal mortality.

Experimental research for tumor VIP receptor imaging

International Nuclear Information System (INIS)

Li Qianwei; Tan Tianzhi

1998-01-01

To study the possibility of radioactive labelled vasoactive intestinal peptide (VIP) for tumor VIP receptor imaging. 125 I-VIP was prepared by chloramine-T method, and purified by Sephadex G-50 column chromatography. The bioactivity and stability of 125 I-VIP were measured by silica 60 F 254 TLC and competition test to SGC7901 cell in vitro. The biodistribution of 125 I-VIP was studied in the nude mice bearing tumor. The results showed that labelled rate of 125 I was 73.8%, the specific activity was 18.2 PBq/mol, the radiochemical purity (RCP) was over 98% and remained 96.3% after 48 days stored at -80 degree C. The specific binding of 125 I-VIP to the SGC7901 cell was inhibited by VIP in dose dependence in the competition experiment. The radioactivity of tumor was higher than that of muscles in all phases (P<0.05-0.01), the peak activity of tumor occurred at 30 min (3.58 +- 0.48ID%/g) and the peak ratio of T/N occurred at 60 min after the injection. The activity of lungs was obviously higher than that of blood, the intestine was always in low level. Most of the activity in the body was mainly eliminated from kidney. The present study demonstrated that the radioactive labelled VIP is a promising agent for tumor VIP receptor scintigraphy

Tumor-specific chromosome mis-segregation controls cancer plasticity by maintaining tumor heterogeneity.

Directory of Open Access Journals (Sweden)

Yuanjie Hu

Full Text Available Aneuploidy with chromosome instability is a cancer hallmark. We studied chromosome 7 (Chr7 copy number variation (CNV in gliomas and in primary cultures derived from them. We found tumor heterogeneity with cells having Chr7-CNV commonly occurs in gliomas, with a higher percentage of cells in high-grade gliomas carrying more than 2 copies of Chr7, as compared to low-grade gliomas. Interestingly, all Chr7-aneuploid cell types in the parental culture of established glioma cell lines reappeared in single-cell-derived subcultures. We then characterized the biology of three syngeneic glioma cultures dominated by different Chr7-aneuploid cell types. We found phenotypic divergence for cells following Chr7 mis-segregation, which benefited overall tumor growth in vitro and in vivo. Mathematical modeling suggested the involvement of chromosome instability and interactions among cell subpopulations in restoring the optimal equilibrium of tumor cell types. Both our experimental data and mathematical modeling demonstrated that the complexity of tumor heterogeneity could be enhanced by the existence of chromosomes with structural abnormality, in addition to their mis-segregations. Overall, our findings show, for the first time, the involvement of chromosome instability in maintaining tumor heterogeneity, which underlies the enhanced growth, persistence and treatment resistance of cancers.

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.

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.

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.

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

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.

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.

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.

Galectin-1 Inhibitor OTX008 Induces Tumor Vessel Normalization and Tumor Growth Inhibition in Human Head and Neck Squamous Cell Carcinoma Models.

Science.gov (United States)

Koonce, Nathan A; Griffin, Robert J; Dings, Ruud P M

2017-12-09

Galectin-1 is a hypoxia-regulated protein and a prognostic marker in head and neck squamous cell carcinomas (HNSCC). Here we assessed the ability of non-peptidic galectin-1 inhibitor OTX008 to improve tumor oxygenation levels via tumor vessel normalization as well as tumor growth inhibition in two human HNSCC tumor models, the human laryngeal squamous carcinoma SQ20B and the human epithelial type 2 HEp-2. Tumor-bearing mice were treated with OTX008, Anginex, or Avastin and oxygen levels were determined by fiber-optics and molecular marker pimonidazole binding. Immuno-fluorescence was used to determine vessel normalization status. Continued OTX008 treatment caused a transient reoxygenation in SQ20B tumors peaking on day 14, while a steady increase in tumor oxygenation was observed over 21 days in the HEp-2 model. A >50% decrease in immunohistochemical staining for tumor hypoxia verified the oxygenation data measured using a partial pressure of oxygen (pO₂) probe. Additionally, OTX008 induced tumor vessel normalization as tumor pericyte coverage increased by approximately 40% without inducing any toxicity. Moreover, OTX008 inhibited tumor growth as effectively as Anginex and Avastin, except in the HEp-2 model where Avastin was found to suspend tumor growth. Galectin-1 inhibitor OTX008 transiently increased overall tumor oxygenation via vessel normalization to various degrees in both HNSCC models. These findings suggest that targeting galectin-1-e.g., by OTX008-may be an effective approach to treat cancer patients as stand-alone therapy or in combination with other standards of care.

Physical and biological dosimetry at the RA-3 facility for small animal irradiation: preliminary BNCT studies in an experimental model of oral cancer

International Nuclear Information System (INIS)

Pozzi, Emiliano; Miller, Marcelo; Thorp, Silvia I.; Heber, Elisa M.; Trivillin, Veronica A.; Zarza, Leandro; Estryk, Guillermo; Schwint, Amanda E.; Nigg, David W.

2007-01-01

Boron Neutron Capture Therapy (BNCT) is a binary treatment modality based on the capture reaction that occurs between thermal neutrons and boron-10 atoms that accumulate selectively in tumor tissue, emitting high linear energy transfer (LET), short range (5-9 microns) particles (alpha y 7 Li). Thus, BNCT would potentially target tumor tissue selectively, sparing normal tissue. Herein we evaluated the feasibility of treating experimental oral mucosa tumors with BNCT at RA-3 (CAE) employing the hamster cheek pouch oral cancer model and characterized the irradiation field at the RA-3 facility. We evaluated the therapeutic effect on tumor of BNCT mediated by BPA in the hamster cheek pouch oral cancer model and the potential radio toxic effects in normal tissue. We evidenced a moderate biological response in tumor, with no radio toxic effects in normal tissue following irradiations with no shielding for the animal body. Given the sub-optimal therapeutic response, we designed and built a 6 Li 2 CO 3 shielding for the body of the animal to increase the irradiation dose to tumor, without exceeding normal tissue radio tolerance. The measured absolute magnitude of thermal neutron flux and the characterization of the beam with and without the shielding in place, suggest that the irradiation facility in the thermal column of RA-3 would afford an excellent platform to perform BNCT studies in vitro and in vivo in small experimental animals. The present findings must be confirmed and extended by performing in vivo BNCT radiobiological studies in small experimental animals, employing the shielding device for the animal body. (author) [es

Treatment of Experimental Brain Tumors with Trombospondin-1 Derived Peptides: an In Vivo Imaging Study

Directory of Open Access Journals (Sweden)

A. Bogdanov, Jr.

1999-11-01

Full Text Available Antiangiogenic and antiproliferative effects of synthetic D-reverse peptides derived from the type 1 repeats of thrombospondin (TSP1 [1,2] were studied in rodent C6 glioma and 9L gliosarcomas. To directly measure tumor size and vascular parameters, we employed in vivo magnetic resonance (MR imaging and corroborated results by traditional morphometric tissue analysis. Rats bearing either C6 or 9L tumors were treated with TSP1-derived peptide (D-reverse amKRFKQDGGWSHWSPWSSac, n=13 or a control peptide (D-reverse am KRAKQAGGASHASPASSac, n=12 at 10 mg/kg, administered either intravenously or through subcutaneous miniosmotic pumps starting 10 days after tumor implantation. Eleven days later, the effect of peptide treatment was evaluated. TSP1 peptide-treated 9L tumors (50.7±44.2 mm3, n=7 and C6 tumors (41.3±34.2 mm3, n=6 were significantly smaller than tumors treated with control peptide (9L: 215.7±67.8 mm3, n=6; C6:184.2±105.2 mm3, n=6. In contrast, the in vivo vascular volume fraction, the mean vascular area (determined by microscopy, and the microvascular density of tumors were not significantly different in any of the experimental groups. In cell culture, TSP1, and the amKRFKQDGGWSHWSPWSSac peptide showed antiproliferative effects against C6 with an IC of 45 nM for TSP1. These results indicate that TSP1derived peptides retard brain tumor growth presumably as a result of slower de novo blood vessel formation and synergistic direct antiproliferative effects on tumor cells. We also show that in vivo MR imaging can be used to assess treatment efficacy of novel antiangiogenic drugs non-invasively, which has obvious implications for clinical trials.

Dynamic {sup 11}C-methionine PET analysis has an additional value for differentiating malignant tumors from granulomas: an experimental study using small animal PET

Energy Technology Data Exchange (ETDEWEB)

Zhao, Songji; Zhao, Yan [Hokkaido University, Department of Nuclear Medicine, Graduate School of Medicine, Sapporo (Japan); Hokkaido University, Department of Tracer Kinetics and Bioanalysis, Graduate School of Medicine, Sapporo (Japan); Kuge, Yuji; Hatano, Toshiyuki [Hokkaido University, Central Institute of Isotope Science, Sapporo (Japan); Yi, Min; Kohanawa, Masashi [Hokkaido University, Department of Advanced Medicine, Graduate School of Medicine, Sapporo (Japan); Magota, Keiichi; Tamaki, Nagara [Hokkaido University, Department of Nuclear Medicine, Graduate School of Medicine, Sapporo (Japan); Nishijima, Ken-ichi [Hokkaido University, Department of Molecular Imaging, Graduate School of Medicine, Sapporo (Japan)

2011-10-15

We evaluated whether the dynamic profile of L-{sup 11}C-methionine ({sup 11}C-MET) may have an additional value in differentiating malignant tumors from granulomas in experimental rat models by small animal positron emission tomography (PET). Rhodococcus aurantiacus and allogenic rat C6 glioma cells were inoculated, respectively, into the right and left calf muscles to generate a rat model bearing both granulomas and tumors (n = 6). Ten days after the inoculations, dynamic {sup 11}C-MET PET was performed by small animal PET up to 120 min after injection of {sup 11}C-MET. The next day, after overnight fasting, the rats were injected with {sup 18}F-2-deoxy-2-fluoro-D-glucose ({sup 18}F-FDG), and dynamic {sup 18}F-FDG PET was performed up to 180 min. The time-activity curves, static images, and mean standardized uptake value (SUV) in the lesions were calculated. {sup 11}C-MET uptake in the granuloma showed a slow exponential clearance after an initial distribution, while the uptake in the tumor gradually increased with time. The dynamic pattern of {sup 11}C-MET uptake in the granuloma was significantly different from that in the tumor (p < 0.001). In the static analysis of {sup 11}C-MET, visual assessment and SUV analysis could not differentiate the tumor from the granuloma in all cases, although the mean SUV in the granuloma (1.48 {+-} 0.09) was significantly lower than that in the tumor (1.72 {+-} 0.18, p < 0.01). The dynamic patterns, static images, and mean SUVs of {sup 18}F-FDG in the granuloma were similar to those in the tumor (p = NS). Dynamic {sup 11}C-MET PET has an additional value for differentiating malignant tumors from granulomatous lesions, which deserves further elucidation in clinical settings. (orig.)

State-Dependent Impulsive Control Strategies for a Tumor-Immune Model

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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.

Effects of exercise on tumor physiology and metabolism.

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Pedersen, Line; Christensen, Jesper Frank; Hojman, Pernille

2015-01-01

Exercise is a potent regulator of a range of physiological processes in most tissues. Solid epidemiological data show that exercise training can reduce disease risk and mortality for several cancer diagnoses, suggesting that exercise training may directly regulate tumor physiology and metabolism. Here, we review the body of literature describing exercise intervention studies performed in rodent tumor models and elaborate on potential mechanistic effects of exercise on tumor physiology. Exercise has been shown to reduce tumor incidence, tumor multiplicity, and tumor growth across numerous different transplantable, chemically induced or genetic tumor models. We propose 4 emerging mechanistic effects of exercise, including (1) vascularization and blood perfusion, (2) immune function, (3) tumor metabolism, and (4) muscle-to-cancer cross-talk, and discuss these in details. In conclusion, exercise training has the potential to be a beneficial and integrated component of cancer management, but has yet to fully elucidate its potential. Understanding the mechanistic effects of exercise on tumor physiology is warranted. Insight into these mechanistic effects is emerging, but experimental intervention studies are still needed to verify the cause-effect relationship between these mechanisms and the control of tumor growth.

Hyperbolastic modeling of tumor growth with a combined treatment of iodoacetate and dimethylsulphoxide

International Nuclear Information System (INIS)

Eby, Wayne M; Tabatabai, Mohammad A; Bursac, Zoran

2010-01-01

An understanding of growth dynamics of tumors is important in understanding progression of cancer and designing appropriate treatment strategies. We perform a comparative study of the hyperbolastic growth models with the Weibull and Gompertz models, which are prevalently used in the field of tumor growth. The hyperbolastic growth models H1, H2, and H3 are applied to growth of solid Ehrlich carcinoma under several different treatments. These are compared with results from Gompertz and Weibull models for the combined treatment. The growth dynamics of the solid Ehrlich carcinoma with the combined treatment are studied using models H1, H2, and H3, and the models are highly accurate in representing the growth. The growth dynamics are also compared with the untreated tumor, the tumor treated with only iodoacetate, and the tumor treated with only dimethylsulfoxide, and the combined treatment. The hyperbolastic models prove to be effective in representing and analyzing the growth dynamics of the solid Ehrlich carcinoma. These models are more precise than Gompertz and Weibull and show less error for this data set. The precision of H3 allows for its use in a comparative analysis of tumor growth rates between the various treatments

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

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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.

Microenvironmental independence associated with tumor progression.

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Anderson, Alexander R A; Hassanein, Mohamed; Branch, Kevin M; Lu, Jenny; Lobdell, Nichole A; Maier, Julie; Basanta, David; Weidow, Brandy; Narasanna, Archana; Arteaga, Carlos L; Reynolds, Albert B; Quaranta, Vito; Estrada, Lourdes; Weaver, Alissa M

2009-11-15

Tumor-microenvironment interactions are increasingly recognized to influence tumor progression. To understand the competitive dynamics of tumor cells in diverse microenvironments, we experimentally parameterized a hybrid discrete-continuum mathematical model with phenotypic trait data from a set of related mammary cell lines with normal, transformed, or tumorigenic properties. Surprisingly, in a resource-rich microenvironment, with few limitations on proliferation or migration, transformed (but not tumorigenic) cells were most successful and outcompeted other cell types in heterogeneous tumor simulations. Conversely, constrained microenvironments with limitations on space and/or growth factors gave a selective advantage to phenotypes derived from tumorigenic cell lines. Analysis of the relative performance of each phenotype in constrained versus unconstrained microenvironments revealed that, although all cell types grew more slowly in resource-constrained microenvironments, the most aggressive cells were least affected by microenvironmental constraints. A game theory model testing the relationship between microenvironment resource availability and competitive cellular dynamics supports the concept that microenvironmental independence is an advantageous cellular trait in resource-limited microenvironments.

Modeling the oxygen microheterogeneity of tumors for photodynamic therapy dosimetry

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Pogue, Brian W.; Paulsen, Keith D.; O'Hara, Julia A.; Hoopes, P. Jack; Swartz, Harold

2000-03-01

Photodynamic theory of tumors uses optical excitation of a sensitizing drug within tissue to produce large deposits of singlet oxygen, which are thought to ultimately cause the tumor destruction. Predicting dose deposition of singlet oxygen in vivo is challenging because measurement of this species in vivo is not easily achieved. But it is possible to follow the concentration of oxygen in vivo, and so measuring the oxygen concentration transients during PDT may provide a viable method of estimating the delivered dose of singlet oxygen. However modeling the microscopic heterogeneity of the oxygen distribution within a tumor is non-trivial, and predicting the microscopic dose deposition requires further study, but this study present the framework and initial calibration needed or modeling oxygen transport in complex geometries. Computational modeling with finite elements provides a versatile structure within which oxygen diffusion and consumption can be modeled within realistic tissue geometries. This study develops the basic tools required to simulate a tumor region, and examines the role of (i) oxygen supply and consumption rates, (ii) inter- capillary spacing, (iii) photosensitizer distribution, and (iv) differences between simulated tumors and those derived directly from histology. The result of these calculations indicate that realistic tumor tissue capillary networks can be simulated using the finite element method, without excessive computational burden for 2D regions near 1 mm2, and 3D regions near 0.1mm3. These simulations can provide fundamental information about tissue and ways to implement appropriate oxygen measurements. These calculations suggest that photodynamic therapy produces the majority of singlet oxygen in and near the blood vessels, because these are the sites of highest oxygen tension. These calculations support the concept that tumor vascular regions are the major targets for PDT dose deposition.

Anti-tumor activity of tetrodotoxin extracted from the Masked Puffer ...

African Journals Online (AJOL)

Anti-tumor activity of tetrodotoxins extracted from the skin of the Masked Puffer fish (Arothron diadematus) from the Red Sea was evaluated using the Ehrlich ascite carcinoma tumor model in mice. Activity was assessed using a variety of cellular and liver biochemical parameters. Experimental mice were divided into 4 equal ...

Tumor blood vessel "normalization" improves the therapeutic efficacy of boron neutron capture therapy (BNCT) in experimental oral cancer

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D. W. Nigg

2012-01-01

We previously demonstrated the efficacy of BNCT mediated by boronophenylalanine (BPA) to treat tumors in a hamster cheek pouch model of oral cancer with no normal tissue radiotoxicity and moderate, albeit reversible, mucositis in precancerous tissue around treated tumors. It is known that boron targeting of the largest possible proportion of tumor cells contributes to the success of BNCT and that tumor blood vessel normalization improves drug delivery to the tumor. Within this context, the aim of the present study was to evaluate the effect of blood vessel normalization on the therapeutic efficacy and potential radiotoxicity of BNCT in the hamster cheek pouch model of oral cancer.

Tumor blood vessel 'normalization' improves the therapeutic efficacy of boron neutron capture therapy (BNCT) in experimental oral cancer

International Nuclear Information System (INIS)

Nigg, D.W.

2012-01-01

We previously demonstrated the efficacy of BNCT mediated by boronophenylalanine (BPA) to treat tumors in a hamster cheek pouch model of oral cancer with no normal tissue radiotoxicity and moderate, albeit reversible, mucositis in precancerous tissue around treated tumors. It is known that boron targeting of the largest possible proportion of tumor cells contributes to the success of BNCT and that tumor blood vessel normalization improves drug delivery to the tumor. Within this context, the aim of the present study was to evaluate the effect of blood vessel normalization on the therapeutic efficacy and potential radiotoxicity of BNCT in the hamster cheek pouch model of oral cancer.

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

A new survival model for hyperthermic intraperitoneal chemotherapy (HIPEC) in tumor-bearing rats in the treatment of peritoneal carcinomatosis

International Nuclear Information System (INIS)

Pelz, Joerg OW; Doerfer, Joerg; Hohenberger, Werner; Meyer, Thomas

2005-01-01

Cytoreduction followed by hyperthermic intraperitoneal chemotherapy (HIPEC) improves survival in patients with peritoneal carcinomatosis of colorectal origin. Animal models are important in the evaluation of new treatment modalities. The purpose of this study was to devise an experimental setting which can be routinely used for the investigation of HIPEC in peritoneal carcinomatosis. A new peritoneal perfusion system in tumor bearing rats were tested. For this purpose CC531 colon carcinoma cells were implanted intraperitoneally in Wag/Rija rats. After 10 days of tumor growth the animals were randomized into three groups of six animals each: group 1: control (n = 6), group 2: HIPEC with mitomycin C in a concentration of 15 mg/m 2 (n = 6), group III: mitomycin C i.p. as monotherapy in a concentration of 10 mg/m 2 (n = 6). After 10 days, total tumor weight and the extent of tumor spread, as classified by the modified Peritoneal Cancer Index (PCI), were assessed by autopsy of the animals. No postoperative deaths were observed. Conjunctivitis, lethargy and loss of appetite were the main side effects in the HIPEC group. No severe locoregional or systemic toxity was observed. All control animals developed massive tumor growth. Tumor load was significantly reduced in the treatment group and was lowest in group II. The combination of hyperthermia with MMC resulted in an increased tumoricidal effect in the rat model. The presented model provides an opportunity to study the mechanism and effect of hyperthermic intraperitoneal chemotherapy and new drugs for this treatment modality

Establishment of a tumor neovascularization animal model with biomaterials in rabbit corneal pouch.

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Chu, Yu-Ping; Li, Hong-Chuan; Ma, Ling; Xia, Yang

2018-06-01

The present animal model of tumor neovascularization most often used by researchers is zebrafish. For studies on human breast cancer cell neovascularization, a new animal model was established to enable a more convenient study of tumor neovascularization. A sodium alginate-gelatin blend gel system was used to design the new animal model. The model was established using rabbit corneal pouch implantation. Then, the animal model was validated by human breast cancer cell lines MCF-7-Kindlin-2 and MCF-7-CMV. The experiment intuitively observed the relationship between tumor and neovascularization, and demonstrated the advantages of this animal model in the study of tumor neovascularization. The use of sodium alginate-gelatin blends to establish tumor neovascularization in a rabbit corneal pouch is a novel and ideal method for the study of neovascularization. It may be a better animal model for expanding the research in this area. Copyright © 2018 Elsevier Inc. All rights reserved.

Whole tumor antigen vaccination using dendritic cells: Comparison of RNA electroporation and pulsing with UV-irradiated tumor cells

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Benencia Fabian

2008-04-01

Full Text Available Abstract Because of the lack of full characterization of tumor associated antigens for solid tumors, whole antigen use is a convenient approach to tumor vaccination. Tumor RNA and apoptotic tumor cells have been used as a source of whole tumor antigen to prepare dendritic cell (DC based tumor vaccines, but their efficacy has not been directly compared. Here we compare directly RNA electroporation and pulsing of DCs with whole tumor cells killed by ultraviolet (UV B radiation using a convenient tumor model expressing human papilloma virus (HPV E6 and E7 oncogenes. Although both approaches led to DCs presenting tumor antigen, electroporation with tumor cell total RNA induced a significantly higher frequency of tumor-reactive IFN-gamma secreting T cells, and E7-specific CD8+ lymphocytes compared to pulsing with UV-irradiated tumor cells. DCs electroporated with tumor cell RNA induced a larger tumor infiltration by T cells and produced a significantly stronger delay in tumor growth compared to DCs pulsed with UV-irradiated tumor cells. We conclude that electroporation with whole tumor cell RNA and pulsing with UV-irradiated tumor cells are both effective in eliciting antitumor immune response, but RNA electroporation results in more potent tumor vaccination under the examined experimental conditions.

Optimization of experimental human leukemia models (review

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D. D. Pankov

2012-01-01

Full Text Available Actual problem of assessing immunotherapy prospects including antigenpecific cell therapy using animal models was covered in this review.Describe the various groups of currently existing animal models and methods of their creating – from different immunodeficient mice to severalvariants of tumor cells engraftment in them. The review addresses the possibility of tumor stem cells studying using mouse models for the leukemia treatment with adoptive cell therapy including WT1. Also issues of human leukemia cells migration and proliferation in a mice withdifferent immunodeficiency degree are discussed. To assess the potential immunotherapy efficacy comparison of immunodeficient mouse model with clinical situation in oncology patients after chemotherapy is proposed.

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

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Desai, Sejal; Srambikkal, Nishad; Yadav, Hansa D.; Shetake, Neena; Balla, Murali M. S.; Kumar, Amit; Ray, Pritha; Ghosh, Anu

2016-01-01

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 insight about

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

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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

Simulation of glioblastoma multiforme (GBM) tumor cells using ising model on the Creutz Cellular Automaton

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Züleyha, Artuç; Ziya, Merdan; Selçuk, Yeşiltaş; Kemal, Öztürk M.; Mesut, Tez

2017-11-01

Computational models for tumors have difficulties due to complexity of tumor nature and capacities of computational tools, however, these models provide visions to understand interactions between tumor and its micro environment. Moreover computational models have potential to develop strategies for individualized treatments for cancer. To observe a solid brain tumor, glioblastoma multiforme (GBM), we present a two dimensional Ising Model applied on Creutz cellular automaton (CCA). The aim of this study is to analyze avascular spherical solid tumor growth, considering transitions between non tumor cells and cancer cells are like phase transitions in physical system. Ising model on CCA algorithm provides a deterministic approach with discrete time steps and local interactions in position space to view tumor growth as a function of time. Our simulation results are given for fixed tumor radius and they are compatible with theoretical and clinic data.

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

International Nuclear Information System (INIS)

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

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

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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.

Anti-inflammatory effects of jojoba liquid wax in experimental models.

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Habashy, Ramy R; Abdel-Naim, Ashraf B; Khalifa, Amani E; Al-Azizi, Mohammed M

2005-02-01

Jojoba [Simmondsia chinensis (Link 1822) Schneider 1907] is an arid perennial shrub grown in several American and African countries. Jojoba seeds, which are rich in liquid wax, were used in folk medicine for diverse ailments. In the current study, the potential anti-inflammatory activity of jojoba liquid wax (JLW) was evaluated in a number of experimental models. Results showed that JLW caused reduction of carrageenin-induced rat paw oedema in addition to diminishing prostaglandin E2 (PGE2) level in the inflammatory exudates. In a test for anti-inflammatory potential utilizing the chick's embryo chroioallantoic membrane (CAM), JLW also caused significant lowering of granulation tissue formation. Topical application of JLW reduced ear oedema induced by croton oil in rats. In the same animal model, JLW also reduced neutrophil infiltration, as indicated by decreased myeloperoxidase (MPO) activity. In addition, JLW ameliorated histopathological changes affected by croton oil application. In the lipopolysaccharide (LPS)-induced inflammation in air pouch in rats, JLW reduced nitric oxide (NO) level and tumor necrosis factor-alpha (TNF-alpha) release. In conclusion, this study demonstrates the effectiveness of JLW in combating inflammation in several experimental models. Further investigations are needed to identify the active constituents responsible for the anti-inflammatory property of JLW.

Variables affecting the tumor localization of 131I-antiferritin in experimental hepatoma

International Nuclear Information System (INIS)

Rostock, R.A.; Klein, J.L.; Kopher, K.A.; Order, S.E.

1984-01-01

Ferritin is both a normal tissue- and tumor-associated protein. The in vivo localization of 131 I-radiolabeled antitumor ferritin and normal IgG antibodies in the H-4-II-E rat hepatoma model was investigated in both tumor and normal tissues over a dose range of 0.67 micrograms to 5 mg of normal and antiferritin IgG and at labeling ratios (microCi 131 I per micrograms IgG) of 15:1, 5:1, and 1:10. The total dose from nonpenetrating radiation in rads was calculated and demonstrated a maximum of 2.9 times greater dose deposition (rads) of antiferritin than normal IgG in hepatoma without specific increase in binding in normal tissues. The maximum tumor targeting achieved was dependent on the amount of injected IgG and not on the labeling ratio or procedure. The binding in tumor could be inhibited by unlabeled antiferritin but not by unlabeled normal rabbit IgG and demonstrated the requirement of specificity for tumor binding. Normal tissues did not target with antiferritin. Most normal tissues have a capacity to bind normal and antiferritin IgG nonspecifically that is linear in relationship to the amount of injected IgG. The results demonstrate that 131 I-antiferritin selectively targets ferritin-secreting hepatoma over normal tissues and that the amount of targeting is dependent on the amount of antiferritin injected. The physiologic reasons for such selective localization is not known, but the term ''biologic window'' has been used to describe the differential availability of tumor ferritin for binding

Development of NMR imaging using CEST agents: application to brain tumor in a rodent model

International Nuclear Information System (INIS)

Flament, J.

2012-01-01

The study aimed at developing saturation transfer imaging of lipoCEST contrast agents for the detection of angiogenesis in a U87 mouse brain tumor model. A lipoCEST with a sensitivity threshold of 100 pM in vitro was optimized in order to make it compatible with CEST imaging in vivo. Thanks to the development of an experimental setup dedicated to CEST imaging, we evaluated lipoCEST to detect specifically tumor angiogenesis. We demonstrated for the first time that lipoCEST visualization was feasible in vivo in a mouse brain after intravenous injection. Moreover, the integrin α v β 3 over expressed during tumor angiogenesis can be specifically targeted using a functionalized lipoCEST with RGD peptide. The specific association between the RGD-lipoCEST and its target α v β 3 was confirmed by immunohistochemical data and fluorescence microscopy. Finally, in order to tend to a molecular imaging protocol by CEST-MRI, we developed a quantification tool of lipoCEST contrast agents. This tool is based on modeling of proton exchange processes in vivo. By taking into account both B0 and B1 fields inhomogeneities which can dramatically alter CEST contrast, we showed that the accuracy of our quantification tool was 300 pM in vitro. The tool was applied on in vivo data acquired on the U87 mouse model and the maximum concentration of RGD-lipoCEST linked to their molecular targets was evaluated to 1.8 nM. (author) [fr

Combination radiotherapy in an orthotopic mouse brain tumor model.

Science.gov (United States)

Kramp, Tamalee R; Camphausen, Kevin

2012-03-06

Glioblastoma multiforme (GBM) are the most common and aggressive adult primary brain tumors. In recent years there has been substantial progress in the understanding of the mechanics of tumor invasion, and direct intracerebral inoculation of tumor provides the opportunity of observing the invasive process in a physiologically appropriate environment. As far as human brain tumors are concerned, the orthotopic models currently available are established either by stereotaxic injection of cell suspensions or implantation of a solid piece of tumor through a complicated craniotomy procedure. In our technique we harvest cells from tissue culture to create a cell suspension used to implant directly into the brain. The duration of the surgery is approximately 30 minutes, and as the mouse needs to be in a constant surgical plane, an injectable anesthetic is used. The mouse is placed in a stereotaxic jig made by Stoetling (figure 1). After the surgical area is cleaned and prepared, an incision is made; and the bregma is located to determine the location of the craniotomy. The location of the craniotomy is 2 mm to the right and 1 mm rostral to the bregma. The depth is 3 mm from the surface of the skull, and cells are injected at a rate of 2 μl every 2 minutes. The skin is sutured with 5-0 PDS, and the mouse is allowed to wake up on a heating pad. From our experience, depending on the cell line, treatment can take place from 7-10 days after surgery. Drug delivery is dependent on the drug composition. For radiation treatment the mice are anesthetized, and put into a custom made jig. Lead covers the mouse's body and exposes only the brain of the mouse. The study of tumorigenesis and the evaluation of new therapies for GBM require accurate and reproducible brain tumor animal models. Thus we use this orthotopic brain model to study the interaction of the microenvironment of the brain and the tumor, to test the effectiveness of different therapeutic agents with and without

Neutrophils responsive to endogenous IFN-beta regulate tumor angiogenesis and growth in a mouse tumor model.

Science.gov (United States)

Jablonska, Jadwiga; Leschner, Sara; Westphal, Kathrin; Lienenklaus, Stefan; Weiss, Siegfried

2010-04-01

Angiogenesis is a hallmark of malignant neoplasias, as the formation of new blood vessels is required for tumors to acquire oxygen and nutrients essential for their continued growth and metastasis. However, the signaling pathways leading to tumor vascularization are not fully understood. Here, using a transplantable mouse tumor model, we have demonstrated that endogenous IFN-beta inhibits tumor angiogenesis through repression of genes encoding proangiogenic and homing factors in tumor-infiltrating neutrophils. We determined that IFN-beta-deficient mice injected with B16F10 melanoma or MCA205 fibrosarcoma cells developed faster-growing tumors with better-developed blood vessels than did syngeneic control mice. These tumors displayed enhanced infiltration by CD11b+Gr1+ neutrophils expressing elevated levels of the genes encoding the proangiogenic factors VEGF and MMP9 and the homing receptor CXCR4. They also expressed higher levels of the transcription factors c-myc and STAT3, known regulators of VEGF, MMP9, and CXCR4. In vitro, treatment of these tumor-infiltrating neutrophils with low levels of IFN-beta restored expression of proangiogenic factors to control levels. Moreover, depletion of these neutrophils inhibited tumor growth in both control and IFN-beta-deficient mice. We therefore suggest that constitutively produced endogenous IFN-beta is an important mediator of innate tumor surveillance. Further, we believe our data help to explain the therapeutic effect of IFN treatment during the early stages of cancer development.

The T61 human breast cancer xenograft: an experimental model of estrogen therapy of breast cancer

DEFF Research Database (Denmark)

Brunner, N; Spang-Thomsen, M; Cullen, K

1996-01-01

Endocrine therapy is one of the principal treatment modalities of breast cancer, both in an adjuvant setting and in advanced disease. The T61 breast cancer xenograft described here provides an experimental model of the effects of estrogen treatment at a molecular level. T61 is an estrogen receptor......-II), but not transforming growth factor beta-I (TGF-beta1). Of these, IGF-II is the only peptide whose expression is altered by endocrine therapy. Treatment of T61-bearing nude mice with physiologic doses of estrogen is accompanied by loss of IGF-II mRNA expression within 24 hours, and rapid regression of tumor. T61 tumor...

Visualization of Tumor Angiogenesis Using MR Imaging Contrast Agent Gd-DTPA-anti-VEGF Receptor 2 Antibody Conjugate in a Mouse Tumor Model

International Nuclear Information System (INIS)

Jun, Hong Young; Yin, Hong Hua; Kim, Sun Hee; Park, Seong Hoon; Kim, Hun Soo; Yoon Kwon Ha Yoon

2010-01-01

To visualize tumor angiogenesis using the MRI contrast agent, Gd- DTPA-anti-VEGF receptor 2 antibody conjugate, with a 4.7-Tesla MRI instrument in a mouse model. We designed a tumor angiogenesis-targeting T1 contrast agent that was prepared by the bioconjugation of gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) and an anti-vascular endothelial growth factor receptor-2 (VEGFR2) antibody. The specific binding of the agent complex to cells that express VEGFR2 was examined in cultured murine endothelial cells (MS-1 cells) with a 4.7-Tesla magnetic resonance imaging scanner. Angiogenesis-specific T1 enhancement was imaged with the Gd-DTPA-anti-VEGFR2 antibody conjugate using a CT-26 adenocarcinoma tumor model in eight mice. As a control, the use of the Gd-DTPA-anti-rat immunoglobulin G (Gd-DTPA-anti-rat IgG) was imaged with a tumor model in eight mice. Statistical significance was assessed using the Mann-Whitney test. Tumor tissue was examined by immunohistochemical analysis. The Gd-DTPA-anti-VEGFR2 antibody conjugate showed predominant binding to cultured endothelial cells that expressed a high level of VEGFR2. Signal enhancement was approximately three-fold for in vivo T1-weighted MR imaging with the use of the Gd-DTPA-anti-VEGFR2 antibody conjugate as compared with the Gd-DTPA-rat IgG in the mouse tumor model (p < 0.05). VEGFR2 expression in CT-26 tumor vessels was demonstrated using immunohistochemical staining. MR imaging using the Gd-DTPA-anti-VEGFR2 antibody conjugate as a contrast agent is useful in visualizing noninvasively tumor angiogenesis in a murine tumor model

Visualization of Tumor Angiogenesis Using MR Imaging Contrast Agent Gd-DTPA-anti-VEGF Receptor 2 Antibody Conjugate in a Mouse Tumor Model

Energy Technology Data Exchange (ETDEWEB)

Jun, Hong Young; Yin, Hong Hua; Kim, Sun Hee; Park, Seong Hoon; Kim, Hun Soo; Yoon Kwon Ha Yoon [Wonkwang University School of Medicine, Iksan (Korea, Republic of)

2010-08-15

To visualize tumor angiogenesis using the MRI contrast agent, Gd- DTPA-anti-VEGF receptor 2 antibody conjugate, with a 4.7-Tesla MRI instrument in a mouse model. We designed a tumor angiogenesis-targeting T1 contrast agent that was prepared by the bioconjugation of gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) and an anti-vascular endothelial growth factor receptor-2 (VEGFR2) antibody. The specific binding of the agent complex to cells that express VEGFR2 was examined in cultured murine endothelial cells (MS-1 cells) with a 4.7-Tesla magnetic resonance imaging scanner. Angiogenesis-specific T1 enhancement was imaged with the Gd-DTPA-anti-VEGFR2 antibody conjugate using a CT-26 adenocarcinoma tumor model in eight mice. As a control, the use of the Gd-DTPA-anti-rat immunoglobulin G (Gd-DTPA-anti-rat IgG) was imaged with a tumor model in eight mice. Statistical significance was assessed using the Mann-Whitney test. Tumor tissue was examined by immunohistochemical analysis. The Gd-DTPA-anti-VEGFR2 antibody conjugate showed predominant binding to cultured endothelial cells that expressed a high level of VEGFR2. Signal enhancement was approximately three-fold for in vivo T1-weighted MR imaging with the use of the Gd-DTPA-anti-VEGFR2 antibody conjugate as compared with the Gd-DTPA-rat IgG in the mouse tumor model (p < 0.05). VEGFR2 expression in CT-26 tumor vessels was demonstrated using immunohistochemical staining. MR imaging using the Gd-DTPA-anti-VEGFR2 antibody conjugate as a contrast agent is useful in visualizing noninvasively tumor angiogenesis in a murine tumor model

Biodistribution of Boron compounds in an experimental model of liver metastases for Boron Neutron Capture (BNCT) Studies

International Nuclear Information System (INIS)

Garabalino, Marcela A.; Monti Hughes, Andrea; Molinari, Ana J.; Heber, Elisa M.; Pozzi, Emiliano C.C.; Itoiz, Maria E.; Trivillin, Veronica A.; Schwint, Amanda E.; Nievas, Susana; Aromando, Romina F.

2009-01-01

Boron Neutron Capture Therapy (BNCT) is a binary treatment modality that involves the selective accumulation of 10 B carriers in tumors followed by irradiation with thermal or epithermal neutrons. The high linear energy transfer alpha particles and recoiling 7 Li nuclei emitted during the capture of a thermal neutron by a 10 B nucleus have a short range and a high biological effectiveness. Thus, BNCT would potentially target neoplastic tissue selectively. In previous studies we demonstrated the therapeutic efficacy of different BNCT protocols in an experimental model of oral cancer. More recently we performed experimental studies in normal rat liver that evidenced the feasibility of treating liver metastases employing a novel BNCT protocol proposed by JEC based on ex-situ treatment and partial liver auto-transplant. The aim of the present study was to perform biodistribution studies with different boron compounds and different administration protocols to determine the protocols that would be therapeutically useful in 'in vivo' BNCT studies at the RA-3 Nuclear Reactor in an experimental model of liver metastases in rats. Materials and Methods. A total of 70 BDIX rats (Charles River Lab., MA, USA) were inoculated in the liver with syngeneic colon cancer cells DH/DK12/TRb (ECACC, UK) to induce the development of subcapsular metastatic nodules. 15 days post-inoculation the animals were used for biodistribution studies. A total of 11 protocols were evaluated employing the boron compounds boronophenylalanine (BPA) and GB-10 (Na 2 10 B 1 -0H 10 ), alone or combined employing different doses and administration routes. Tumor, normal tissue and blood samples were processed for boron measurement by ICP-OES. Results. Several protocols proved potentially useful for BNCT studies in terms of absolute boron concentration in tumor and preferential uptake of boron by tumor tissue, i.e. BPA 15.5 mg 10 B/kg iv + GB-10 50 mg 10 B/kg iv; BPA 46.5 mg 10 B/kg ip; BPA 46.5 mg 10 B/kg ip

Immuno-therapy with anti-CTLA4 antibodies in tolerized and non-tolerized mouse tumor models.

Directory of Open Access Journals (Sweden)

Jonas Persson

Full Text Available Monoclonal antibodies specific for cytotoxic T lymphocyte-associated antigen 4 (anti-CTLA4 are a novel form of cancer immunotherapy. While preclinical studies in mouse tumor models have shown anti-tumor efficacy of anti-CTLA4 injection or expression, anti-CTLA4 treatment in patients with advanced cancers had disappointing therapeutic benefit. These discrepancies have to be addressed in more adequate pre-clinical models. We employed two tumor models. The first model is based on C57Bl/6 mice and syngeneic TC-1 tumors expressing HPV16 E6/E7. In this model, the HPV antigens are neo-antigens, against which no central tolerance exists. The second model involves mice transgenic for the proto-oncogen neu and syngeneic mouse mammary carcinoma (MMC cells. In this model tolerance to Neu involves both central and peripheral mechanisms. Anti-CTLA4 delivery as a protein or expression from gene-modified tumor cells were therapeutically efficacious in the non-tolerized TC-1 tumor model, but had no effect in the MMC-model. We also used the two tumor models to test an immuno-gene therapy approach for anti-CTLA4. Recently, we used an approach based on hematopoietic stem cells (HSC to deliver the relaxin gene to tumors and showed that this approach facilitates pre-existing anti-tumor T-cells to control tumor growth in the MMC tumor model. However, unexpectedly, when used for anti-CTLA4 gene delivery in this study, the HSC-based approach was therapeutically detrimental in both the TC-1 and MMC models. Anti-CTLA4 expression in these models resulted in an increase in the number of intratumoral CD1d+ NKT cells and in the expression of TGF-β1. At the same time, levels of pro-inflammatory cytokines and chemokines, which potentially can support anti-tumor T-cell responses, were lower in tumors of mice that received anti-CTLA4-HSC therapy. The differences in outcomes between the tolerized and non-tolerized models also provide a potential explanation for the low efficacy

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.

EXPERIMENTAL RATIONALE FOR HEMOSTATIC SUTURES DURING RESECTION OF THE KIDNEY FOR ITS TUMOR

Directory of Open Access Journals (Sweden)

V. M. Popkov

2014-08-01

Full Text Available The investigation deals with the study of the biomechanical properties of renal tissues and the comparison of different hemostatic suture procedures used during resection of the kidney for its tumor. The performed experimental study allows one to recommend that a renal capsule as the organ’s most stable and plastic part must be necessarily inserted into the hemostatic suture on both sides. The elastic modulus (Young’s modulus serves as an integral indicator of the deformation-strength properties of renal tissues, which enables it to be recommended for the wider use in experimental and clinical studies. The proposed modified suture can minimize the number of postoperative bleedings from the renal parenchyma and reduce the time of surgery, thereby improving the results of organ-saving treatment in patients with kidney cancer.

The establishment of transmissible venereal tumor lung cancer model in canine and the observation of its biological characteristics

International Nuclear Information System (INIS)

Sun Zhichao; Dong Weihua; Xiao Xiangsheng; Zhu Ruimin; Chen mofan; Wang Zhi

2010-01-01

Objective: To establish an allogeneic transplanted lung cancer model in canine by percutaneously injecting canine transmissible venereal tumor (CTVT) cell suspension and to observe its biological characteristics. Methods: Under CT guidance fresh CTVT cell suspension was inoculated into the middle or posterior lobe of lungs through percutaneous puncturing needle in 12 beagle dogs. Cyclosporin was administrated orally to obtain immunosuppression. Tumor growth and metastasis were judged by chest CT scanning at regular intervals (every 1-2 weeks). The daily mental and physical condition of the dogs was observed. Autopsy and pathological examination were performed when the animals died naturally or at the tenth week after the procedure when the animals were sacrificed. Results: A total of 15 sites were inoculated in 12 dogs. The formation of tumor was observed in 2 dogs at the fifth week and in 9 dogs at the sixth week. Ten weeks after the inoculation the formation of tumor was detected in 10 inoculated points in 9 dogs, the inoculation success rate was 66.67%. The mean largest diameter of the tumor at 6, 8 and 10 weeks after the inoculation was (1.059 ± 0.113)cm, (1.827 ± 0.084)cm and (2.189 ± 0.153)cm, respectively. The largest diameter of the tumor nodule was 3.5 cm. Moderate to severe pleural effusion and mediastinal lymph nodes metastasis were found in all the dogs that showed the formation of the tumor. Conclusion: Percutaneous CTVT cell suspension injection can establish an allogeneic canine lung cancer model, which is helpful for the experimental studies related to lung cancer. (authors)

Inflammatory models drastically alter tumor growth and the immune microenvironment in hepatocellular carcinoma.

Science.gov (United States)

Markowitz, Geoffrey J; Michelotti, Gregory A; Diehl, Anna Mae; Wang, Xiao-Fan

2015-04-01

Initiation and progression of hepatocellular carcinoma (HCC) is intimately associated with a chronically diseased liver tissue. This diseased liver tissue background is a drastically different microenvironment from the healthy liver, especially with regard to immune cell prevalence and presence of mediators of immune function. To better understand the consequences of liver disease on tumor growth and the interplay with its microenvironment, we utilized two standard methods of fibrosis induction and orthotopic implantation of tumors into the inflamed and fibrotic liver to mimic the liver condition in human HCC patients. Compared to non-diseased controls, tumor growth was significantly enhanced under fibrotic conditions. The immune cells that infiltrated the tumors were also drastically different, with decreased numbers of natural killer cells but greatly increased numbers of immune-suppressive CD11b + Gr1 hi myeloid cells in both models of fibrosis. In addition, there were model-specific differences: Increased numbers of CD11b + myeloid cells and CD4 + CD25 + T cells were found in tumors in the bile duct ligation model but not in the carbon tetrachloride model. Induction of fibrosis altered the cytokine production of implanted tumor cells, which could have farreaching consequences on the immune infiltrate and its functionality. Taken together, this work demonstrates that the combination of fibrosis induction with orthotopic tumor implantation results in a markedly different tumor microenvironment and tumor growth kinetics, emphasizing the necessity for more accurate modeling of HCC progression in mice, which takes into account the drastic changes in the tissue caused by chronic liver disease.

3D modeling of effects of increased oxygenation and activity concentration in tumors treated with radionuclides and antiangiogenic drugs

Energy Technology Data Exchange (ETDEWEB)

Lagerloef, Jakob H.; Kindblom, Jon; Bernhardt, Peter [Department of Radiation Physics, Goeteborg University, Goeteborg 41345 (Sweden); Department of Oncology, Sahlgrenska University Hospital, Goeteborg 41345 (Sweden); Department of Radiation Physics, Goeteborg University, Goeteborg, Sweden and Department of Nuclear Medicine, Sahlgrenska University Hospital, Goeteborg 41345 (Sweden)

2011-08-15

Purpose: Formation of new blood vessels (angiogenesis) in response to hypoxia is a fundamental event in the process of tumor growth and metastatic dissemination. However, abnormalities in tumor neovasculature often induce increased interstitial pressure (IP) and further reduce oxygenation (pO{sub 2}) of tumor cells. In radiotherapy, well-oxygenated tumors favor treatment. Antiangiogenic drugs may lower IP in the tumor, improving perfusion, pO{sub 2} and drug uptake, by reducing the number of malfunctioning vessels in the tissue. This study aims to create a model for quantifying the effects of altered pO{sub 2}-distribution due to antiangiogenic treatment in combination with radionuclide therapy. Methods: Based on experimental data, describing the effects of antiangiogenic agents on oxygenation of GlioblastomaMultiforme (GBM), a single cell based 3D model, including 10{sup 10} tumor cells, was developed, showing how radionuclide therapy response improves as tumor oxygenation approaches normal tissue levels. The nuclides studied were {sup 90}Y, {sup 131}I, {sup 177}Lu, and {sup 211}At. The absorbed dose levels required for a tumor control probability (TCP) of 0.990 are compared for three different log-normal pO{sub 2}-distributions: {mu}{sub 1} = 2.483, {sigma}{sub 1} = 0.711; {mu}{sub 2} = 2.946, {sigma}{sub 2} = 0.689; {mu}{sub 3} = 3.689, and {sigma}{sub 3} = 0.330. The normal tissue absorbed doses will, in turn, depend on this. These distributions were chosen to represent the expected oxygen levels in an untreated hypoxic tumor, a hypoxic tumor treated with an anti-VEGF agent, and in normal, fully-oxygenated tissue, respectively. The former two are fitted to experimental data. The geometric oxygen distributions are simulated using two different patterns: one Monte Carlo based and one radially increasing, while keeping the log-normal volumetric distributions intact. Oxygen and activity are distributed, according to the same pattern. Results: As tumor pO{sub 2

Oncogenetic tree model of somatic mutations and DNA methylation in colon tumors.

Science.gov (United States)

Sweeney, Carol; Boucher, Kenneth M; Samowitz, Wade S; Wolff, Roger K; Albertsen, Hans; Curtin, Karen; Caan, Bette J; Slattery, Martha L

2009-01-01

Our understanding of somatic alterations in colon cancer has evolved from a concept of a series of events taking place in a single sequence to a recognition of multiple pathways. An oncogenetic tree is a model intended to describe the pathways and sequence of somatic alterations in carcinogenesis without assuming that tumors will fall in mutually exclusive categories. We applied this model to data on colon tumor somatic alterations. An oncogenetic tree model was built using data on mutations of TP53, KRAS2, APC, and BRAF genes, methylation at CpG sites of MLH1 and TP16 genes, methylation in tumor (MINT) markers, and microsatellite instability (MSI) for 971 colon tumors from a population-based series. Oncogenetic tree analysis resulted in a reproducible tree with three branches. The model represents methylation of MINT markers as initiating a branch and predisposing to MSI, methylation of MHL1 and TP16, and BRAF mutation. APC mutation is the first alteration in an independent branch and is followed by TP53 mutation. KRAS2 mutation was placed a third independent branch, implying that it neither depends on, nor predisposes to, the other alterations. Individual tumors were observed to have alteration patterns representing every combination of one, two, or all three branches. The oncogenetic tree model assumptions are appropriate for the observed heterogeneity of colon tumors, and the model produces a useful visual schematic of the sequence of events in pathways of colon carcinogenesis.

Acellular organ scaffolds for tumor tissue engineering

Science.gov (United States)

Guller, Anna; Trusova, Inna; Petersen, Elena; Shekhter, Anatoly; Kurkov, Alexander; Qian, Yi; Zvyagin, Andrei

2015-12-01

Rationale: Tissue engineering (TE) is an emerging alternative approach to create models of human malignant tumors for experimental oncology, personalized medicine and drug discovery studies. Being the bottom-up strategy, TE provides an opportunity to control and explore the role of every component of the model system, including cellular populations, supportive scaffolds and signalling molecules. Objectives: As an initial step to create a new ex vivo TE model of cancer, we optimized protocols to obtain organ-specific acellular matrices and evaluated their potential as TE scaffolds for culture of normal and tumor cells. Methods and results: Effective decellularization of animals' kidneys, ureter, lungs, heart, and liver has been achieved by detergent-based processing. The obtained scaffolds demonstrated biocompatibility and growthsupporting potential in combination with normal (Vero, MDCK) and tumor cell lines (C26, B16). Acellular scaffolds and TE constructs have been characterized and compared with morphological methods. Conclusions: The proposed methodology allows creation of sustainable 3D tumor TE constructs to explore the role of organ-specific cell-matrix interaction in tumorigenesis.

Radiotherapy planning for glioblastoma based on a tumor growth model: improving target volume delineation

Science.gov (United States)

Unkelbach, Jan; Menze, Bjoern H.; Konukoglu, Ender; Dittmann, Florian; Le, Matthieu; Ayache, Nicholas; Shih, Helen A.

2014-02-01

Glioblastoma differ from many other tumors in the sense that they grow infiltratively into the brain tissue instead of forming a solid tumor mass with a defined boundary. Only the part of the tumor with high tumor cell density can be localized through imaging directly. In contrast, brain tissue infiltrated by tumor cells at low density appears normal on current imaging modalities. In current clinical practice, a uniform margin, typically two centimeters, is applied to account for microscopic spread of disease that is not directly assessable through imaging. The current treatment planning procedure can potentially be improved by accounting for the anisotropy of tumor growth, which arises from different factors: anatomical barriers such as the falx cerebri represent boundaries for migrating tumor cells. In addition, tumor cells primarily spread in white matter and infiltrate gray matter at lower rate. We investigate the use of a phenomenological tumor growth model for treatment planning. The model is based on the Fisher-Kolmogorov equation, which formalizes these growth characteristics and estimates the spatial distribution of tumor cells in normal appearing regions of the brain. The target volume for radiotherapy planning can be defined as an isoline of the simulated tumor cell density. This paper analyzes the model with respect to implications for target volume definition and identifies its most critical components. A retrospective study involving ten glioblastoma patients treated at our institution has been performed. To illustrate the main findings of the study, a detailed case study is presented for a glioblastoma located close to the falx. In this situation, the falx represents a boundary for migrating tumor cells, whereas the corpus callosum provides a route for the tumor to spread to the contralateral hemisphere. We further discuss the sensitivity of the model with respect to the input parameters. Correct segmentation of the brain appears to be the most

Radiotherapy planning for glioblastoma based on a tumor growth model: improving target volume delineation

International Nuclear Information System (INIS)

Unkelbach, Jan; Dittmann, Florian; Le, Matthieu; Shih, Helen A; Menze, Bjoern H; Ayache, Nicholas; Konukoglu, Ender

2014-01-01

Glioblastoma differ from many other tumors in the sense that they grow infiltratively into the brain tissue instead of forming a solid tumor mass with a defined boundary. Only the part of the tumor with high tumor cell density can be localized through imaging directly. In contrast, brain tissue infiltrated by tumor cells at low density appears normal on current imaging modalities. In current clinical practice, a uniform margin, typically two centimeters, is applied to account for microscopic spread of disease that is not directly assessable through imaging. The current treatment planning procedure can potentially be improved by accounting for the anisotropy of tumor growth, which arises from different factors: anatomical barriers such as the falx cerebri represent boundaries for migrating tumor cells. In addition, tumor cells primarily spread in white matter and infiltrate gray matter at lower rate. We investigate the use of a phenomenological tumor growth model for treatment planning. The model is based on the Fisher–Kolmogorov equation, which formalizes these growth characteristics and estimates the spatial distribution of tumor cells in normal appearing regions of the brain. The target volume for radiotherapy planning can be defined as an isoline of the simulated tumor cell density. This paper analyzes the model with respect to implications for target volume definition and identifies its most critical components. A retrospective study involving ten glioblastoma patients treated at our institution has been performed. To illustrate the main findings of the study, a detailed case study is presented for a glioblastoma located close to the falx. In this situation, the falx represents a boundary for migrating tumor cells, whereas the corpus callosum provides a route for the tumor to spread to the contralateral hemisphere. We further discuss the sensitivity of the model with respect to the input parameters. Correct segmentation of the brain appears to be the most

Application of Benchtop-magnetic resonance imaging in a nude mouse tumor model

Directory of Open Access Journals (Sweden)

Mäder Karsten

2011-07-01

Full Text Available Abstract Background MRI plays a key role in the preclinical development of new drugs, diagnostics and their delivery systems. However, very high installation and running costs of existing superconducting MRI machines limit the spread of MRI. The new method of Benchtop-MRI (BT-MRI has the potential to overcome this limitation due to much lower installation and almost no running costs. However, due to the low field strength and decreased magnet homogeneity it is questionable, whether BT-MRI can achieve sufficient image quality to provide useful information for preclinical in vivo studies. It was the aim of the current study to explore the potential of BT-MRI on tumor models in mice. Methods We used a prototype of an in vivo BT-MRI apparatus to visualise organs and tumors and to analyse tumor progression in nude mouse xenograft models of human testicular germ cell tumor and colon carcinoma. Results Subcutaneous xenografts were easily identified as relative hypointense areas in transaxial slices of NMR images. Monitoring of tumor progression evaluated by pixel extension analyses based on NMR images correlated with increasing tumor volume calculated by calliper measurement. Gd-BOPTA contrast agent injection resulted in a better differentiation between parts of the urinary tissues and organs due to fast elimination of the agent via kidneys. In addition, interior structuring of tumors could be observed. A strong contrast enhancement within a tumor was associated with a central necrotic/fibrotic area. Conclusions BT-MRI provides satisfactory image quality to visualize organs and tumors and to monitor tumor progression and structure in mouse models.

EFFECTS OF IRRADIATION ON BRAIN VASCULATURE USING AN IN SITU TUMOR MODEL

Science.gov (United States)

Zawaski, Janice A.; Gaber, M. Waleed; Sabek, Omaima M.; Wilson, Christy M.; Duntsch, Christopher D.; Merchant, Thomas E.

2013-01-01

Purpose Damage to normal tissue is a limiting factor in clinical radiotherapy (RT). We tested the hypothesis that the presence of tumor alters the response of normal tissues to irradiation using a rat in situ brain tumor model. Methods and Materials Intravital microscopy was used with a rat cranial window to assess the in situ effect of rat C6 glioma on peritumoral tissue with and without RT. The RT regimen included 40 Gy at 8 Gy/day starting Day 5 after tumor implant. Endpoints included blood–brain barrier permeability, clearance index, leukocyte-endothelial interactions and staining for vascular endothelial growth factor (VEGF) glial fibrillary acidic protein, and apoptosis. To characterize the system response to RT, animal survival and tumor surface area and volume were measured. Sham experiments were performed on similar animals implanted with basement membrane matrix absent of tumor cells. Results The presence of tumor alone increases permeability but has little effect on leukocyte–endothelial interactions and astrogliosis. Radiation alone increases tissue permeability, leukocyte-endothelial interactions, and astrogliosis. The highest levels of permeability and cell adhesion were seen in the model that combined tumor and irradiation; however, the presence of tumor appeared to reduce the volume of rolling leukocytes. Unirradiated tumor and peritumoral tissue had poor clearance. Irradiated tumor and peritumoral tissue had a similar clearance index to irradiated and unirradiated sham-implanted animals. Radiation reduces the presence of VEGF in peritumoral normal tissues but did not affect the amount of apoptosis in the normal tissue. Apoptosis was identified in the tumor tissue with and without radiation. Conclusions We developed a novel approach to demonstrate that the presence of the tumor in a rat intracranial model alters the response of normal tissues to irradiation. PMID:22197233

Effects of Irradiation on Brain Vasculature Using an In Situ Tumor Model

Energy Technology Data Exchange (ETDEWEB)

Zawaski, Janice A. [School of Biomedical Engineering and Imaging, University of Tennessee Health Science Center, Memphis, TN (United States); Gaber, M. Waleed, E-mail: gaber@bcm.edu [School of Biomedical Engineering and Imaging, University of Tennessee Health Science Center, Memphis, TN (United States); Department of Pediatrics, Baylor College of Medicine, Houston, TX (United States); Sabek, Omaima M. [Department of Surgery, Methodist Hospital Research Institute, Houston, TX (United States); Wilson, Christy M. [School of Biomedical Engineering and Imaging, University of Tennessee Health Science Center, Memphis, TN (United States); Duntsch, Christopher D. [Department of Neurosurgery, University of Tennessee Health Science Center, Memphis, TN (United States); Merchant, Thomas E. [School of Biomedical Engineering and Imaging, University of Tennessee Health Science Center, Memphis, TN (United States); Department of Radiation Oncology, St. Jude Children' s Research Hospital, Memphis, TN (United States)

2012-03-01

Purpose: Damage to normal tissue is a limiting factor in clinical radiotherapy (RT). We tested the hypothesis that the presence of tumor alters the response of normal tissues to irradiation using a rat in situ brain tumor model. Methods and Materials: Intravital microscopy was used with a rat cranial window to assess the in situ effect of rat C6 glioma on peritumoral tissue with and without RT. The RT regimen included 40 Gy at 8 Gy/day starting Day 5 after tumor implant. Endpoints included blood-brain barrier permeability, clearance index, leukocyte-endothelial interactions and staining for vascular endothelial growth factor (VEGF) glial fibrillary acidic protein, and apoptosis. To characterize the system response to RT, animal survival and tumor surface area and volume were measured. Sham experiments were performed on similar animals implanted with basement membrane matrix absent of tumor cells. Results: The presence of tumor alone increases permeability but has little effect on leukocyte-endothelial interactions and astrogliosis. Radiation alone increases tissue permeability, leukocyte-endothelial interactions, and astrogliosis. The highest levels of permeability and cell adhesion were seen in the model that combined tumor and irradiation; however, the presence of tumor appeared to reduce the volume of rolling leukocytes. Unirradiated tumor and peritumoral tissue had poor clearance. Irradiated tumor and peritumoral tissue had a similar clearance index to irradiated and unirradiated sham-implanted animals. Radiation reduces the presence of VEGF in peritumoral normal tissues but did not affect the amount of apoptosis in the normal tissue. Apoptosis was identified in the tumor tissue with and without radiation. Conclusions: We developed a novel approach to demonstrate that the presence of the tumor in a rat intracranial model alters the response of normal tissues to irradiation.

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.

An experimental study of the diagnosing value to nude mice model of transplanted human gastric cancer with folate-receptor MR contrast agent

International Nuclear Information System (INIS)

Ding Jianhui; Zeng Mengsu; Zhou Kangrong; Shen Jizhang; Chen Caizhong; Zhong Gaoren; Xue Qiong; Gu Haiyan

2005-01-01

Objective: To evaluate the tumor targeting characteristic by observing signal varying of human gastric cancer transplanted nude mice (SGC-7901 ) using Folate-Receptor MR contrast agent. Methods: As a Folate-Receptor MR contrast agent, Gd-DTPA-Folate was obtained by conjugation of DTPA-Folate and GdCl 3 under specific conditions. Nude mice of subcutaneously transplanted human gastric cancer (SGC-7901) were used as animal models, 12 mice were divided into experimental group (n=6) and control group (n=6) randomly. Both were injected with Gd-DTPA-Folate and Gd-DTPA (contained same gadolinium) via abdominal cavity respectively. Tumor signal varying was observed by T 1 WI after injection of contrast agent immediately, 1, 2, 3, 4, 6, 12 and 24 h, and tumor signal changing of experimental group was compared with that of control group. CNR (contrast noise ratio) was regarded as evaluating mark. Results: Tumor signal intensity of experimental group was increased evidently between 1-2 hours after injecting Gd-DTPA-Folate. Comparison with pre-injection, there was a significant difference (evaluating mark is CNR: q 1 =5.80, q 2 =4.64; P 1 =0.64, q 2 =1.19, P>0.05). Conclusion: Gd-DTPA-Folate shows definite characteristic of tumor targeting effect to nude mice of subcutaneously transplanted human gastric cancer (SGC-7901). (authors)

Tumors in dogs exposed to experimental intraoperative radiotherapy

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Johnstone, Peter A.S.; Laskin, William B.; De Luca, Anne Marie; Barnes, Margaret; Kinsella, Timothy J.; Sindelar, William F.

1996-01-01

Purpose: The frequency of radiation-induced neoplasms was determined in dogs enrolled in the National Cancer Institute canine trials of intraoperative radiotherapy (IORT). Methods and Materials: Twelve protocols assessing normal tissue response to IORT involved 238 dogs in a 15-year trial. Eighty-one dogs were followed for > 24 months postoperatively and were assessed for tumor development; 59 of these animals received IORT. Results: Twelve tumors occurred in the 59 dogs receiving IORT. Nine were in the IORT portals and were considered to be radiation induced. No tumors occurred in 13 sham animals or in 9 animals treated with external beam radiotherapy alone. The frequency of radiation-induced malignancies in dogs receiving IORT was 15%, and was 25% in animals receiving ≥ 25 Gy IORT. Frequency of all tumors, including spontaneous lesions, was 20%. Conclusions: Intraoperative radiotherapy contributed to a high frequency of sarcoma induction in these dogs. Unknown to date in humans involved in clinical trials of IORT, this potential complication should be looked for as long-term survivors are followed

Impact of MR-guided boiling histotripsy in distinct murine tumor models.

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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

Tumor vaccine composed of C-class CpG oligodeoxynucleotides and irradiated tumor cells induces long-term antitumor immunity

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Cerkovnik Petra

2010-09-01

Full Text Available Abstract Background An ideal tumor vaccine should activate both effector and memory immune response against tumor-specific antigens. Beside the CD8+ T cells that play a central role in the generation of a protective immune response and of long-term memory, dendritic cells (DCs are important for the induction, coordination and regulation of the adaptive immune response. The DCs can conduct all of the elements of the immune orchestra and are therefore a fundamental target and tool for vaccination. The present study was aimed at assessing the ability of tumor vaccine composed of C-class CpG ODNs and irradiated melanoma tumor cells B16F1 followed by two additional injections of CpG ODNs to induce the generation of a functional long-term memory response in experimental tumor model in mice (i.p. B16F1. Results It has been shown that the functional memory response in vaccinated mice persists for at least 60 days after the last vaccination. Repeated vaccination also improves the survival of experimental animals compared to single vaccination, whereas the proportion of animals totally protected from the development of aggressive i.p. B16F1 tumors after vaccination repeated three times varies between 88.9%-100.0%. Additionally, the long-term immune memory and tumor protection is maintained over a prolonged period of time of at least 8 months. Finally, it has been demonstrated that following the vaccination the tumor-specific memory cells predominantly reside in bone marrow and peritoneal tissue and are in a more active state than their splenic counterparts. Conclusions In this study we demonstrated that tumor vaccine composed of C-class CpG ODNs and irradiated tumor cells followed by two additional injections of CpG ODNs induces a long-term immunity against aggressive B16F1 tumors.

A nonlinear competitive model of the prostate tumor growth under intermittent androgen suppression.

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Yang, Jing; Zhao, Tong-Jun; Yuan, Chang-Qing; Xie, Jing-Hui; Hao, Fang-Fang

2016-09-07

Hormone suppression has been the primary modality of treatment for prostate cancer. However long-term androgen deprivation may induce androgen-independent (AI) recurrence. Intermittent androgen suppression (IAS) is a potential way to delay or avoid the AI relapse. Mathematical models of tumor growth and treatment are simple while they are capable of capturing the essence of complicated interactions. Game theory models have analyzed that tumor cells can enhance their fitness by adopting genetically determined survival strategies. In this paper, we consider the survival strategies as the competitive advantage of tumor cells and propose a new model to mimic the prostate tumor growth in IAS therapy. Then we investigate the competition effect in tumor development by numerical simulations. The results indicate that successfully IAS-controlled states can be achieved even though the net growth rate of AI cells is positive for any androgen level. There is crucial difference between the previous models and the new one in the phase diagram of successful and unsuccessful tumor control by IAS administration, which means that the suggestions from the models for medication can be different. Furthermore we introduce quadratic logistic terms to the competition model to simulate the tumor growth in the environment with a finite carrying capacity considering the nutrients or inhibitors. The simulations show that the tumor growth can reach an equilibrium state or an oscillatory state with the net growth rate of AI cells being androgen independent. Our results suggest that the competition and the restraint of a limited environment can enhance the possibility of relapse prevention. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cerebral scintigraphy in dogs using gallium 67. Value in the investigation of experimental brain tumors

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Joffre, J.-F.

1975-01-01

The possibility of inducing experimental brain tumors in dogs by intracerebral inoculation of Rous sarcoma virus led to the development of an early diagnosis procedure without any danger for the carrier animal. Already widely used in humans, cerebral gammagraphy, used in dogs in the conditions developed, perfectly satisfy the requirements of harmlessness, precision and reliability. Scintiscans are taken 48 hours after injection of two mCi of carrier-free Ga 67 citrate. Profile and front patterns are obtained by means of a gamma camera connected to an on-line data processing system. Thirteen examinations were carried out under general anesthesia. Three dogs exhibiting positive scintiscan patterns revealed at the autopsy tumors ranging in size from a hazelnut to a walnut. The remaining animals gave negative or dubious patterns, and none of them revealed a tumor larger in size than a pea. The results obtained in this study are encouraging, and it is felt that this method can enable valid diagnosis of the presence of cerebral neoplasias in dogs, provided they are sufficiently large [fr

Noninvasive Assessment of Tumor Cell Proliferation in Animal Models

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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

Inhibition of IL-17A suppresses enhanced-tumor growth in low dose pre-irradiated tumor beds.

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Eun-Jung Lee

Full Text Available Ionizing radiation induces modification of the tumor microenvironment such as tumor surrounding region, which is relevant to treatment outcome after radiotherapy. In this study, the effects of pre-irradiated tumor beds on the growth of subsequently implanted tumors were investigated as well as underlying mechanism. The experimental model was set up by irradiating the right thighs of C3H/HeN mice with 5 Gy, followed by the implantation of HCa-I and MIH-2. Both implanted tumors in the pre-irradiated bed showed accelerated-growth compared to the control. Tumor-infiltrated lymphocyte (TIL levels were increased, as well as pro-tumor factors such as IL-6 and transforming growth factor-beta1 (TGF-β1 in the pre-irradiated group. In particular, the role of pro-tumor cytokine interleukin-17A (IL-17A was investigated as a possible target mechanism because IL-6 and TGF-β are key factors in Th17 cells differentiation from naïve T cells. IL-17A expression was increased not only in tumors, but also in CD4+ T cells isolated from the tumor draining lymph nodes. The effect of IL-17A on tumor growth was confirmed by treating tumors with IL-17A antibody, which abolished the acceleration of tumor growth. These results indicate that the upregulation of IL-17A seems to be a key factor for enhancing tumor growth in pre-irradiated tumor beds.

Simplified realistic human head model for simulating Tumor Treating Fields (TTFields).

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Wenger, Cornelia; Bomzon, Ze'ev; Salvador, Ricardo; Basser, Peter J; Miranda, Pedro C

2016-08-01

Tumor Treating Fields (TTFields) are alternating electric fields in the intermediate frequency range (100-300 kHz) of low-intensity (1-3 V/cm). TTFields are an anti-mitotic treatment against solid tumors, which are approved for Glioblastoma Multiforme (GBM) patients. These electric fields are induced non-invasively by transducer arrays placed directly on the patient's scalp. Cell culture experiments showed that treatment efficacy is dependent on the induced field intensity. In clinical practice, a software called NovoTalTM uses head measurements to estimate the optimal array placement to maximize the electric field delivery to the tumor. Computational studies predict an increase in the tumor's electric field strength when adapting transducer arrays to its location. Ideally, a personalized head model could be created for each patient, to calculate the electric field distribution for the specific situation. Thus, the optimal transducer layout could be inferred from field calculation rather than distance measurements. Nonetheless, creating realistic head models of patients is time-consuming and often needs user interaction, because automated image segmentation is prone to failure. This study presents a first approach to creating simplified head models consisting of convex hulls of the tissue layers. The model is able to account for anisotropic conductivity in the cortical tissues by using a tensor representation estimated from Diffusion Tensor Imaging. The induced electric field distribution is compared in the simplified and realistic head models. The average field intensities in the brain and tumor are generally slightly higher in the realistic head model, with a maximal ratio of 114% for a simplified model with reasonable layer thicknesses. Thus, the present pipeline is a fast and efficient means towards personalized head models with less complexity involved in characterizing tissue interfaces, while enabling accurate predictions of electric field distribution.

Percutaneous radiofrequency ablation of lung tumors in a large animal model.

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Ahrar, Kamran; Price, Roger E; Wallace, Michael J; Madoff, David C; Gupta, Sanjay; Morello, Frank A; Wright, Kenneth C

2003-08-01

Percutaneous radiofrequency ablation (RFA) is accepted therapy for liver tumors in the appropriate clinical setting, but its use in lung neoplasms remains investigational. We undertook this study to evaluate the feasibility and immediate effectiveness of RFA for treatment of both solitary pulmonary nodules and clusters of lung tumors in a large animal model. Percutaneous RFA of 14 lung tumors in five dogs was performed under CT guidance. Animals were euthanatized 8-48 hours after the procedure. The lungs and adjacent structures were harvested for gross and histopathologic evaluation. Five solitary pulmonary nodules (range, 17-26 mm) and three clusters of three nodules each (range, 7-17 mm per nodule) were treated with RFA. All ablations were technically successful. Perilesional ground-glass opacity and small asymptomatic pneumothoraces (n = 4) were visualized during the RFA sessions. One dog developed a large pneumothorax treated with tube thoracostomy but was euthanatized 8 hours post-RFA for persistent pneumothorax and continued breathing difficulty. Follow-up CT 48 hours post-RFA revealed opacification of the whole lung segment. Gross and histopathologic evaluation showed complete thermal coagulation necrosis of all treated lesions without evidence of any viable tumor. The region of thermal coagulation necrosis typically extended to the lung surface. Small regions of pulmonary hemorrhage and congestion often surrounded the areas of coagulation necrosis. RFA can be used to treat both solitary pulmonary nodules and clusters of tumor nodules in the canine lung tumor model. This model may be useful for development of specific RFA protocols for human lung tumors.

Experimental assessment of the role of the blood flow inhibition in hyperglycemia-enhanced radiation injury to tumor

International Nuclear Information System (INIS)

Kozin, S.V.; Sevast'yanov, A.I.; Yarmonenko, S.P.

1986-01-01

Experimental assessment of the role of the blood flow inhibition in enhancement of radiation injury to tumors using short-term hyperglycemia was provided. Experiments on mice with Ehrlich solid carcinoma showed the dependence of a rise of the antitumor effect of preceding radiation induced by glucose and glucose combined with mexamin on a degree of the blood flow inhibition under the influence of these modifying agents. It was established that a considerable enhancement of radiation injury occured but in such tumors where short-term hyperglycemia and mexamin decreased the blood flow level not less than 5-10 fold as estimated by 133 Xe clearance. The results of the above experiments showed that the noticeable inhibition of the blood flow in tumors was a necessary tough, probably, not the only condition for a high efficacy of short-term hyperglycemia used an ajuvant to radiotherapy

Effect of aged garlic extract on immune responses to experimental fibrosarcoma tumor in BALB/c mice.

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Tabari, M Abouhosseini; Ebrahimpour, S

2014-01-01

Aged garlic extract (AGE) has many biological activities including radical scavenging, antioxidative and immunomodulative effects. In this research work, the antitumor and immunomodulatory effects of AGE against fibrosarcoma implanted tumor were studied. WEHI-164 fibrosarcoma cells were implanted subcutaneously on day 0 into the right flank of 40 BALB/c mice at age of 8 weeks. Mice were randomly categorized in two separate groups: First received AGE (100 mg/kg, IP), second group as the control group received phosphate buffered saline. Treatments were carried out 3 times/week. Tumor growth was measured and morbidity was recorded. Subpopulations of CD4+/CD8+ T cells were determined using flow cytometry. WEHI-164 cell specific cytotoxicity of splenocytes and in vitro production of interferon gamma (IFN-γ) and interleukin-4 cytokines were measured. The mice received AGE had significantly longer survival time compared with the control mice. The inhibitory effect on tumor growth was seen in AGE treated mice. The CD4+/CD8+ ratio and in vitro IFN-γ production of splenocytes were significantly increased in AGE group. WEHI-164 specific cytotoxicity of splenocytes from AGE mice was also significantly increased at 25:1 E: T ratio. Administration of AGE resulted in improved immune responses against experimentally implanted fibrosarcoma tumors in BALB/c mice. AGE showed significant effects on inhibition of tumor growth and longevity of survival times.

Novel mouse model for simulating microsurgical tumor excision with facial nerve preservation.

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Lim, Jae H; Boyle, Glen M; Panizza, Benedict

2016-01-01

To determine the feasibility of using a mouse tumor model as a microsurgical training tool for otolaryngology-head and neck surgery (OHNS) trainees. Animal study. We injected athymic nude mice with human cutaneous squamous cell carcinoma (A431 cell line) deep to the parotid region overlying the masseter muscle. We sacrificed the animals 1 to 3 weeks postinjection, once a visible tumor growth was confirmed. We then asked 10 OHNS trainees to excise the tumor with preservation of the facial nerves under a high-magnification dissecting microscope. The trainees graded the tasks in several areas of specific measures using a visual analogue scale (VAS) including 1) tumor texture, 2) surgical realism, 3) usefulness, and 4) difficulty of the task. Noticeable tumor growth occurred within 5 days following A431 cell injection and reached measureable size (0.5-1.5 cm) within 1 to 3 weeks. The tumor displaced the facial nerve laterally and medially, with few demonstrating infiltration of the nerve. VAS scores (± standard deviation) were 8.1 (± 1.7), 7.7 (± 2.5), 9.0 (± 0.9) and 6.6 (± 1.9) for tumor texture, surgical realism, usefulness, and the difficulty of the task, respectively. We demonstrate a novel, reliable and cost-effective mouse model for simulating tumor extirpation microsurgery with preservation of important neural structures. OHNS trainees have found this simulation model to be realistic, useful, and appropriately challenging. © 2015 The American Laryngological, Rhinological and Otological Society, Inc.

Establishment of primary cell culture and an intracranial xenograft model of pediatric ependymoma: a prospect for therapy development and understanding of tumor biology.

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Pavon, Lorena Favaro; Sibov, Tatiana Tais; Caminada de Toledo, Silvia Regina; Mara de Oliveira, Daniela; Cabral, Francisco Romero; Gabriel de Souza, Jean; Boufleur, Pamela; Marti, Luciana C; Malheiros, Jackeline Moraes; Ferreira da Cruz, Edgar; Paiva, Fernando F; Malheiros, Suzana M F; de Paiva Neto, Manoel A; Tannús, Alberto; Mascarenhas de Oliveira, Sérgio; Silva, Nasjla Saba; Cappellano, Andrea Maria; Petrilli, Antonio Sérgio; Chudzinski-Tavassi, Ana Marisa; Cavalheiro, Sérgio

2018-04-24

Ependymoma (EPN), the third most common pediatric brain tumor, is a central nervous system (CNS) malignancy originating from the walls of the ventricular system. Surgical resection followed by radiation therapy has been the primary treatment for most pediatric intracranial EPNs. Despite numerous studies into the prognostic value of histological classification, the extent of surgical resection and adjuvant radiotherapy, there have been relatively few studies into the molecular and cellular biology of EPNs. We elucidated the ultrastructure of the cultured EPN cells and characterized their profile of immunophenotypic pluripotency markers (CD133, CD90, SSEA-3, CXCR4). We established an experimental EPN model by the intracerebroventricular infusion of EPN cells labeled with multimodal iron oxide nanoparticles (MION), thereby generating a tumor and providing a clinically relevant animal model. MRI analysis was shown to be a valuable tool when combined with effective MION labeling techniques to accompany EPN growth. We demonstrated that GFAP/CD133+CD90+/CD44+ EPN cells maintained key histopathological and growth characteristics of the original patient tumor. The characterization of EPN cells and the experimental model could facilitate biological studies and preclinical drug screening for pediatric EPNs. In this work, we established notoriously challenging primary cell culture of anaplastic EPNs (WHO grade III) localized in the posterior fossa (PF), using EPNs obtained from 1 to 10-year-old patients ( n = 07), and then characterized their immunophenotype and ultrastructure to finally develop a xenograft model.

A 3-D model of tumor progression based on complex automata driven by particle dynamics.

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Wcisło, Rafał; Dzwinel, Witold; Yuen, David A; Dudek, Arkadiusz Z

2009-12-01

The dynamics of a growing tumor involving mechanical remodeling of healthy tissue and vasculature is neglected in most of the existing tumor models. This is due to the lack of efficient computational framework allowing for simulation of mechanical interactions. Meanwhile, just these interactions trigger critical changes in tumor growth dynamics and are responsible for its volumetric and directional progression. We describe here a novel 3-D model of tumor growth, which combines particle dynamics with cellular automata concept. The particles represent both tissue cells and fragments of the vascular network. They interact with their closest neighbors via semi-harmonic central forces simulating mechanical resistance of the cell walls. The particle dynamics is governed by both the Newtonian laws of motion and the cellular automata rules. These rules can represent cell life-cycle and other biological interactions involving smaller spatio-temporal scales. We show that our complex automata, particle based model can reproduce realistic 3-D dynamics of the entire system consisting of the tumor, normal tissue cells, blood vessels and blood flow. It can explain phenomena such as the inward cell motion in avascular tumor, stabilization of tumor growth by the external pressure, tumor vascularization due to the process of angiogenesis, trapping of healthy cells by invading tumor, and influence of external (boundary) conditions on the direction of tumor progression. We conclude that the particle model can serve as a general framework for designing advanced multiscale models of tumor dynamics and it is very competitive to the modeling approaches presented before.

The rat as animal model in breast cancer research: a histopathological study of radiation- and hormone-induced rat mammary tumors

International Nuclear Information System (INIS)

Zwieten, M.J. van.

1984-01-01

One of the goals of this monograph is to present data on the frequency of mammary neoplasms following irradiation and/or hormone administration in intact and castrated female rats of three strains allowed to live their natural life spans. These data are intended to give an overview of the effects of radiation and hormonal manipulation on the mammary gland based on histological examination of necropsied rats and using standard morphological criteria for mammary tumors. The second goal of this monograph is to provide detailed histological descriptions of the mammary tumors found in the various experimental groups as well as in several groups of untreated control rats. The aims are to examine whether possible strain-related and treatment-related differences in morphology or growth patterns exist, as well as to define the pathogensis of radiation-induced rat mammary tumors through the study of early lesions. An attempt will be made to describe tumor characteristics which may be of comparative value in identifying tumor types (and their induction methods) useful as models for specific human breast neoplasms. A rat mammary tumor classification system reflecting the morphological features useful for comparative purposes is also presented. (Auth.)

Dendritic Cells in the Context of Human Tumors: Biology and Experimental Tools.

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Volovitz, Ilan; Melzer, Susanne; Amar, Sarah; Bocsi, József; Bloch, Merav; Efroni, Sol; Ram, Zvi; Tárnok, Attila

2016-01-01

Dendritic cells (DC) are the most potent and versatile antigen-presenting cells (APC) in the immune system. DC have an exceptional ability to comprehend the immune context of a captured antigen based on molecular signals identified from its vicinity. The analyzed information is then conveyed to other immune effector cells. Such capability enables DC to play a pivotal role in mediating either an immunogenic response or immune tolerance towards an acquired antigen. This review summarizes current knowledge on DC in the context of human tumors. It covers the basics of human DC biology, elaborating on the different markers, morphology and function of the different subsets of human DC. Human blood-borne DC are comprised of at least three subsets consisting of one plasmacytoid DC (pDC) and two to three myeloid DC (mDC) subsets. Some tissues have unique DC. Each subset has a different phenotype and function and may induce pro-tumoral or anti-tumoral effects. The review also discusses two methods fundamental to the research of DC on the single-cell level: multicolor flow cytometry (FCM) and image-based cytometry (IC). These methods, along with new genomics and proteomics tools, can provide high-resolution information on specific DC subsets and on immune and tumor cells with which they interact. The different layers of collected biological data may then be integrated using Immune-Cytomics modeling approaches. Such novel integrated approaches may help unravel the complex network of cellular interactions that DC carry out within tumors, and may help harness this complex immunological information into the development of more effective treatments for cancer.

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

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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.

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

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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.

Linear-quadratic model predictions for tumor control probability

International Nuclear Information System (INIS)

Yaes, R.J.

1987-01-01

Sigmoid dose-response curves for tumor control are calculated from the linear-quadratic model parameters α and Β, obtained from human epidermoid carcinoma cell lines, and are much steeper than the clinical dose-response curves for head and neck cancers. One possible explanation is the presence of small radiation-resistant clones arising from mutations in an initially homogeneous tumor. Using the mutation theory of Delbruck and Luria and of Goldie and Coldman, the authors discuss the implications of such radiation-resistant clones for clinical radiation therapy

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.

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

International Nuclear Information System (INIS)

Ko, Eun Young; Lee, Sang Hoon; Kim, Hak Hee; Kim, Sung Moon; Shin, Myung Jin; Kim, Nam Kug; Gong, Gyung Yub

2008-01-01

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

Effects of nursing intervention models on social adaption capability development in preschool children with malignant tumors: a randomized control trial.

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Yu, Lu; Mo, Lin; Tang, Yan; Huang, Xiaoyan; Tan, Juan

2014-06-01

The objectives of this study are to compare the effects of two nursing intervention models on the ability of preschool children with malignant tumors to socialize and to determine if these interventions improved their social adaption capability (SAC) and quality of life. Inpatient preschool children with malignant tumors admitted to the hospital between December 2009 and March 2012 were recruited and randomized into either the experimental or control groups. The control group received routine nursing care, and the experimental group received family-centered nursing care, including physical, psychological, and social interventions. The Infants-Junior Middle School Student's Social-Life Abilities Scale was used to evaluate SAC development of participants. Participants (n = 240) were recruited and randomized into two groups. After the intervention, the excellent and normal SAC rates were 27.5% and 55% in the experimental group, respectively, compared with 2.5% and 32.5% in the control group (p intervention, SAC in experimental group was improved compared with before intervention (54.68 ± 10.85 vs 79.9 ± 22.3, p intervention in the control group (54.70 ± 11.47 vs. 52 ± 15.8, p = 0.38). The family-centered nursing care model that included physical, psychological, and social interventions improved the SAC of children with malignancies compared with children receiving routine nursing care. Establishing a standardized family-school-community-hospital hierarchical multi-management intervention model for children is important to the efficacy of long-term interventions and to the improvement of SAC of children with malignancies. Copyright © 2014 John Wiley & Sons, Ltd.

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

Improved Debulking of Peritoneal Tumor Implants by Near-Infrared Fluorescent Nanobody Image Guidance in an Experimental Mouse Model.

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Debie, Pieterjan; Vanhoeij, Marian; Poortmans, Natalie; Puttemans, Janik; Gillis, Kris; Devoogdt, Nick; Lahoutte, Tony; Hernot, Sophie

2017-10-31

Debulking followed by combination chemotherapy is currently regarded as the most effective treatment for advanced ovarian cancer. Prognosis depends drastically on the degree of debulking. Accordingly, near-infrared (NIR) fluorescence imaging has been proposed to revolutionize cancer surgery by acting as a sensitive, specific, and real-time tool enabling visualization of cancer lesions. We have previously developed a NIR-labeled nanobody that allows fast, specific, and high-contrast imaging of HER2-positive tumors. In this study, we applied this tracer during fluorescence-guided surgery in a mouse model and investigated the effect on surgical efficiency. 0.5 × 10 6 SKOV3.IP1-Luc+ cells were inoculated intraperitoneally in athymic mice and were allowed to grow for 30 days. Two nanomoles of IRDye800CW-anti-HER2 nanobody was injected intravenously. After 1h30, mice were killed, randomized in two groups, and subjected to surgery. In the first animal group (n = 7), lesions were removed by a conventional surgical protocol, followed by excision of remaining fluorescent tissue using a NIR camera. The second group of mice (n = 6) underwent directly fluorescence-guided surgery. Bioluminescence imaging was performed before and after surgery. Resected tissue was categorized as visualized during conventional surgery or not, fluorescent or not, and bioluminescent positive or negative. Fluorescence imaging allowed clear visualization of tumor nodules within the abdomen, up to submillimeter-sized lesions. Fluorescence guidance resulted in significantly reduced residual tumor as compared to conventional surgery. Moreover, sensitivity increased from 59.3 to 99.0 %, and the percentage of false positive lesions detected decreased from 19.6 to 7.1 %. This study demonstrates the advantage of intraoperative fluorescence imaging using nanobody-based tracers on the efficiency of debulking surgery.

Modeling and simulation of tumor-influenced high resolution real-time physics-based breast models for model-guided robotic interventions

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Neylon, John; Hasse, Katelyn; Sheng, Ke; Santhanam, Anand P.

2016-03-01

Breast radiation therapy is typically delivered to the patient in either supine or prone position. Each of these positioning systems has its limitations in terms of tumor localization, dose to the surrounding normal structures, and patient comfort. We envision developing a pneumatically controlled breast immobilization device that will enable the benefits of both supine and prone positioning. In this paper, we present a physics-based breast deformable model that aids in both the design of the breast immobilization device as well as a control module for the device during every day positioning. The model geometry is generated from a subject's CT scan acquired during the treatment planning stage. A GPU based deformable model is then generated for the breast. A mass-spring-damper approach is then employed for the deformable model, with the spring modeled to represent a hyperelastic tissue behavior. Each voxel of the CT scan is then associated with a mass element, which gives the model its high resolution nature. The subject specific elasticity is then estimated from a CT scan in prone position. Our results show that the model can deform at >60 deformations per second, which satisfies the real-time requirement for robotic positioning. The model interacts with a computer designed immobilization device to position the breast and tumor anatomy in a reproducible location. The design of the immobilization device was also systematically varied based on the breast geometry, tumor location, elasticity distribution and the reproducibility of the desired tumor location.

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.

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...

Sensitivity of tumor motion simulation accuracy to lung biomechanical modeling approaches and parameters.

Science.gov (United States)

Tehrani, Joubin Nasehi; Yang, Yin; Werner, Rene; Lu, Wei; Low, Daniel; Guo, Xiaohu; Wang, Jing

2015-11-21

Finite element analysis (FEA)-based biomechanical modeling can be used to predict lung respiratory motion. In this technique, elastic models and biomechanical parameters are two important factors that determine modeling accuracy. We systematically evaluated the effects of lung and lung tumor biomechanical modeling approaches and related parameters to improve the accuracy of motion simulation of lung tumor center of mass (TCM) displacements. Experiments were conducted with four-dimensional computed tomography (4D-CT). A Quasi-Newton FEA was performed to simulate lung and related tumor displacements between end-expiration (phase 50%) and other respiration phases (0%, 10%, 20%, 30%, and 40%). Both linear isotropic and non-linear hyperelastic materials, including the neo-Hookean compressible and uncoupled Mooney-Rivlin models, were used to create a finite element model (FEM) of lung and tumors. Lung surface displacement vector fields (SDVFs) were obtained by registering the 50% phase CT to other respiration phases, using the non-rigid demons registration algorithm. The obtained SDVFs were used as lung surface displacement boundary conditions in FEM. The sensitivity of TCM displacement to lung and tumor biomechanical parameters was assessed in eight patients for all three models. Patient-specific optimal parameters were estimated by minimizing the TCM motion simulation errors between phase 50% and phase 0%. The uncoupled Mooney-Rivlin material model showed the highest TCM motion simulation accuracy. The average TCM motion simulation absolute errors for the Mooney-Rivlin material model along left-right, anterior-posterior, and superior-inferior directions were 0.80 mm, 0.86 mm, and 1.51 mm, respectively. The proposed strategy provides a reliable method to estimate patient-specific biomechanical parameters in FEM for lung tumor motion simulation.

Tumor Control Probability Modeling for Stereotactic Body Radiation Therapy of Early-Stage Lung Cancer Using Multiple Bio-physical Models

Science.gov (United States)

Liu, Feng; Tai, An; Lee, Percy; Biswas, Tithi; Ding, George X.; El Naqa, Isaam; Grimm, Jimm; Jackson, Andrew; Kong, Feng-Ming (Spring); LaCouture, Tamara; Loo, Billy; Miften, Moyed; Solberg, Timothy; Li, X Allen

2017-01-01

Purpose To analyze pooled clinical data using different radiobiological models and to understand the relationship between biologically effective dose (BED) and tumor control probability (TCP) for stereotactic body radiotherapy (SBRT) of early-stage non-small cell lung cancer (NSCLC). Method and Materials The clinical data of 1-, 2-, 3-, and 5-year actuarial or Kaplan-Meier TCP from 46 selected studies were collected for SBRT of NSCLC in the literature. The TCP data were separated for Stage T1 and T2 tumors if possible, otherwise collected for combined stages. BED was calculated at isocenters using six radiobiological models. For each model, the independent model parameters were determined from a fit to the TCP data using the least chi-square (χ2) method with either one set of parameters regardless of tumor stages or two sets for T1 and T2 tumors separately. Results The fits to the clinic data yield consistent results of large α/β ratios of about 20 Gy for all models investigated. The regrowth model that accounts for the tumor repopulation and heterogeneity leads to a better fit to the data, compared to other 5 models where the fits were indistinguishable between the models. The models based on the fitting parameters predict that the T2 tumors require about additional 1 Gy physical dose at isocenters per fraction (≤5 fractions) to achieve the optimal TCP when compared to the T1 tumors. Conclusion This systematic analysis of a large set of published clinical data using different radiobiological models shows that local TCP for SBRT of early-stage NSCLC has strong dependence on BED with large α/β ratios of about 20 Gy. The six models predict that a BED (calculated with α/β of 20) of 90 Gy is sufficient to achieve TCP ≥ 95%. Among the models considered, the regrowth model leads to a better fit to the clinical data. PMID:27871671

Anti-tumor effects of 125I radioactive particles implantation on transplantated tumor model of human breast cancer cells in nude mice

International Nuclear Information System (INIS)

Xiao Zhongdi; Liang Chunlin; Zhang Guoli; Jing Yue; Zhang Yucheng; Gai Baodong

2011-01-01

Objective: To study the anti-tumor effects of 125 I radioactive particles implantation on transplantated tumor model of human breast cancer cells in nude mice and clarify their anti-tumor mechanisms. Methods 120 nude mice transplantated with human breast cancer cells MCF-7 were randomly divided into 3 groups (n=40): 125 I radioactive particles implanted group, non-radioactive particles implanted group and non-particles implanted group. The articles were implanted into mice according to Pairs system principle. The expressions of Fas mRNA and protein and the activaties of caspase-3 and caspase-8 enzyme were detected by RT-PCR and Western blotting. The changes of cell cycle were detected by flow cytometry. Results: Compared with non-radioactive particles implanted group and non-particles implanted group, the size of cancer tissues in 125 I radioactive particles implanted group was reduced significantly (P 0 /G 1 phase was significantly increased (P 125 I radioactive particles into transplantated tumor model of human breast cancer cells can kill tumor cells, inhibit the growth cycle of tumor cells and induce the apoptosis of tumor cells in nude mice. (authors)

Comprehensive preclinical evaluation of a multi-physics model of liver tumor radiofrequency ablation.

Science.gov (United States)

Audigier, Chloé; Mansi, Tommaso; Delingette, Hervé; Rapaka, Saikiran; Passerini, Tiziano; Mihalef, Viorel; Jolly, Marie-Pierre; Pop, Raoul; Diana, Michele; Soler, Luc; Kamen, Ali; Comaniciu, Dorin; Ayache, Nicholas

2017-09-01

We aim at developing a framework for the validation of a subject-specific multi-physics model of liver tumor radiofrequency ablation (RFA). The RFA computation becomes subject specific after several levels of personalization: geometrical and biophysical (hemodynamics, heat transfer and an extended cellular necrosis model). We present a comprehensive experimental setup combining multimodal, pre- and postoperative anatomical and functional images, as well as the interventional monitoring of intra-operative signals: the temperature and delivered power. To exploit this dataset, an efficient processing pipeline is introduced, which copes with image noise, variable resolution and anisotropy. The validation study includes twelve ablations from five healthy pig livers: a mean point-to-mesh error between predicted and actual ablation extent of 5.3 ± 3.6 mm is achieved. This enables an end-to-end preclinical validation framework that considers the available dataset.

Method of hyperthermia and tumor size influence effectiveness of doxorubicin release from thermosensitive liposomes in experimental tumors.

Science.gov (United States)

Willerding, Linus; Limmer, Simone; Hossann, Martin; Zengerle, Anja; Wachholz, Kirsten; Ten Hagen, Timo L M; Koning, Gerben A; Sroka, Ronald; Lindner, Lars H; Peller, Michael

2016-01-28

Systemic chemotherapy of solid tumors could be enhanced by local hyperthermia (HT) in combination with thermosensitive liposomes (TSL) as drug carriers. In such an approach, effective HT of the tumor is considered essential for successful triggering local drug release and targeting of the drug to the tumor. To investigate the effect of HT method on the effectiveness of drug delivery, a novel laser-based HT device designed for the use in magnetic resonance imaging (MRI) was compared systematically with the frequently used cold light lamp and water bath HT. Long circulating phosphatidyldiglycerol-based TSL (DPPG2-TSL) with encapsulated doxorubicin (DOX) were used as drug carrier enabling intravascular drug release. Experiments were performed in male Brown Norway rats with a syngeneic soft tissue sarcoma (BN 175) located on both hind legs. One tumor was heated while the second tumor remained unheated as a reference. Six animals were investigated per HT method. DPPG2-TSL were injected i.v. at a stable tumor temperature above 40°C. Thereafter, temperature was maintained for 60min. Total DOX concentration in plasma, tumor tissue and muscle was determined post therapy by HPLC. Finally, the new laser-based device was tested in a MRI environment at 3T using DPPG2-TSL with encapsulated Gd-based contrast agent. All methods showed effective DOX delivery by TSL with 4.5-23.1ng/mg found in the heated tumors. In contrast, DOX concentration in the non-heated tumors was 0.5±0.1ng/mg. Independent of used HT methods, higher DOX levels were found in the smaller tumors. In comparison water bath induced lowest DOX delivery but still showing fourfold higher DOX concentrations compared to the non-heated tumors. With the laser-based applicator, a 13 fold higher DOX deposition was possible for large tumors and a 15 fold higher for the small tumors, respectively. Temperature gradients in the tumor tissue were higher with the laser and cold light lamp (-0.3°C/mm to -0.5°C/mm) compared to

Central nervous system tumors

International Nuclear Information System (INIS)

Gavin, P.R.; Fike, J.R.; Hoopes, P.J.

1995-01-01

Central nervous system (CNS) tumors are relatively common in veterinary medicine, with most diagnoses occurring in the canine and feline species. Numerous tumor types from various cells or origins have been identified with the most common tumors being meningiomas and glial cell tumors. Radiation therapy is often used as an aid to control the clinical signs associated with these neoplasms. In general, these tumors have a very low metastatic potential, such that local control offers substantial benefit. Experience in veterinary radiation oncology would indicate that many patients benefit from radiation treatment. Current practice indicates the need for computed tomography or magnetic resonance imaging studies. These highly beneficial studies are used for diagnosis, treatment planning, and to monitor treatment response. Improvements in treatment planning and radiation delivered to the tumor, while sparing the normal tissues, should improve local control and decrease potential radiation related problems to the CNS. When possible, multiple fractions of 3 Gy or less should be used. The tolerance dose to the normal tissue with this fractionation schedule is 50 to 55 Gy. The most common and serious complications of radiation for CNS tumors is delayed radiation myelopathy and necrosis. Medical management of the patient during radiation therapy requires careful attention to anesthetic protocols, and medications to reduce intracranial pressure that is often elevated in these patients. Canine brain tumors have served as an experimental model to test numerous new treatments. Increased availability of advanced imaging modalities has spawned increased detection of these neoplasms. Early detection of these tumors with appropriate aggressive therapy should prove beneficial to many patients

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

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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.

MR staging of malignant musculoskeletal tumors: An experimental study on MR and pathologic correlation of rabbit VX-2 carcinoma

International Nuclear Information System (INIS)

Kang, Heung Sik; Chung, Sung Hoon; KIm, Cheol Woo; Kim, Seong Moon; Im, Jung Gi; Han, Man Chung

1993-01-01

To evaluate the reliability of MR imaging in tissue characterization and depiction of tumor boundaries, we performed MR pathologic correlation using parosteally implanted VX-2 carcinoma in 17 rabbit thighs. T1-weighted, T2-weighted and Gd-DTPA enhanced T1-weighted axial images were obtained 10-30 days after tumor implantation. After the animals were killed, frozen and sectioned along the MR imaging planes, and histopathologic examination were done. For accurate MR pathologic correlation, rabbit were fixed on the cardboard plate to minimize position change during the procedure. Tumor boundaries depicted on MR images were larger than those depicted on the specimen. Small tumors were surrounded by capsule-like loose connective tissue. Loose connective tissue became compact with tumor growth. This connective tissue showed high signal intensity on both T2-weighted and Gd-DTPA enhanced T1-weighted images. Muscle atrophy with fatty tissue accumulation around the tumor also contributed to the high signal intensity on MR images. Peritumoral edema and inflammatory reaction were not remarkable. Six of 8 cases with bone marrow fibrosis were detected on MR images. We concluded that peritumoral loose connective tissue and muscle atrophy exaggerated the size of experimentally induced malignant musculoskeletal tumors on MR images

Skin carcinogenesis in man and in experimental models

International Nuclear Information System (INIS)

Hecker, E.; Jung, E.G.; Marks, F.; Tilgen, W.

1993-01-01

This book presents an updated overview of the current state of the art in scientific, experimental and clinical investigations on the generation and the prevention of cancer of the skin. From the achievements presented, marked refinements in the assessment of the risk of cancer, by environmental and endogenous factors, including tumor virus, will be stimulated. They include the problem of the stratospheric 'ozone holes' above both poles of the earth causing much public concern as expressed by current headlines in the media and by the United Nations Environmental Program. Moreover, new ideas will merge for developing specific approaches to explore the mechanistic, i.e. ultimately the molecular-biological, causes of skin cancer and others. In addition, the experimental utilization of oncogens and of other techniques of molecular biology at all levels of the biology of tissues and cells, may open up entirely new facets in the research on skin cancer. Detailed knowledge of the mechanistic aspects of skin carcinogenesis may give important hints with respect to 'tailor-make' and utilize new anti-tumor agents in the therapy of skin cancer for the benefit of the cancer patient. (orig.). 67 figs., 44 tabs

TumorML: Concept and requirements of an in silico cancer modelling markup language.

Science.gov (United States)

Johnson, David; Cooper, Jonathan; McKeever, Steve

2011-01-01

This paper describes the initial groundwork carried out as part of the European Commission funded Transatlantic Tumor Model Repositories project, to develop a new markup language for computational cancer modelling, TumorML. In this paper we describe the motivations for such a language, arguing that current state-of-the-art biomodelling languages are not suited to the cancer modelling domain. We go on to describe the work that needs to be done to develop TumorML, the conceptual design, and a description of what existing markup languages will be used to compose the language specification.

Image-based modeling of tumor shrinkage in head and neck radiation therapy

Energy Technology Data Exchange (ETDEWEB)

Chao Ming; Xie Yaoqin; Moros, Eduardo G.; Le, Quynh-Thu; Xing Lei [Department of Radiation Oncology, Stanford University School of Medicine, 875 Blake Wilbur Drive, Stanford, California 94305-5847 and Department of Radiation Oncology, University of Arkansas for Medical Sciences, 4301 W. Markham Street, Little Rock, Arkansas 72205-1799 (United States); Department of Radiation Oncology, Stanford University School of Medicine, 875 Blake Wilbur Drive, Stanford, California 94305-5847 (United States); Department of Radiation Oncology, University of Arkansas for Medical Sciences, 4301 W. Markham Street, Little Rock, Arkansas 72205-1799 (United States); Department of Radiation Oncology, Stanford University School of Medicine, 875 Blake Wilbur Drive, Stanford, California 94305-5847 (United States)

2010-05-15

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.

Engineering 3D Models of Tumors and Bone to Understand Tumor-Induced Bone Disease and Improve Treatments

Science.gov (United States)

Kwakwa, Kristin A.; Vanderburgh, Joseph P.; Guelcher, Scott A.

2018-01-01

Purpose of Review Bone is a structurally unique microenvironment that presents many challenges for the development of 3D models for studying bone physiology and diseases, including cancer. As researchers continue to investigate the interactions within the bone microenvironment, the development of 3D models of bone has become critical. Recent Findings 3D models have been developed that replicate some properties of bone, but have not fully reproduced the complex structural and cellular composition of the bone microenvironment. This review will discuss 3D models including polyurethane, silk, and collagen scaffolds that have been developed to study tumor-induced bone disease. In addition, we discuss 3D printing techniques used to better replicate the structure of bone. Summary 3D models that better replicate the bone microenvironment will help researchers better understand the dynamic interactions between tumors and the bone microenvironment, ultimately leading to better models for testing therapeutics and predicting patient outcomes. PMID:28646444

Numerical simulation of avascular tumor growth

Energy Technology Data Exchange (ETDEWEB)

Slezak, D Fernandez; Suarez, C; Soba, A; Risk, M; Marshall, G [Laboratorio de Sistemas Complejos, Departamento de Computacion, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (C1428EGA) Buenos Aires (Argentina)

2007-11-15

A mathematical and numerical model for the description of different aspects of microtumor development is presented. The model is based in the solution of a system of partial differential equations describing an avascular tumor growth. A detailed second-order numeric algorithm for solving this system is described. Parameters are swiped to cover a range of feasible physiological values. While previous published works used a single set of parameters values, here we present a wide range of feasible solutions for tumor growth, covering a more realistic scenario. The model is validated by experimental data obtained with a multicellular spheroid model, a specific type of in vitro biological model which is at present considered to be optimum for the study of complex aspects of avascular microtumor physiology. Moreover, a dynamical analysis and local behaviour of the system is presented, showing chaotic situations for particular sets of parameter values at some fixed points. Further biological experiments related to those specific points may give potentially interesting results.

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

Microvessel organization and structure in experimental brain tumors: microvessel populations with distinctive structural and functional properties.

Science.gov (United States)

Schlageter, K E; Molnar, P; Lapin, G D; Groothuis, D R

1999-11-01

We studied microvessel organization in five brain tumor models (ENU, MSV, RG-2, S635cl15, and D-54MG) and normal brain, including microvessel diameter (LMVD), intermicrovessel distance (IMVD), microvessel density (MVD), surface area (S(v)), and orientation. LMVD and IMVD were larger and MVD was lower in tumors than normal brain. S(v) in tumors overlapped normal brain values and orientation was random in both tumors and brain. ENU and RG-2 tumors and brain were studied by electron microscopy. Tumor microvessel wall was thicker than that of brain. ENU and normal brain microvessels were continuous and nonfenestrated. RG-2 microvessels contained fenestrations and endothelial gaps; the latter had a maximum major axis of 3.0 microm. Based on anatomic measurements, the pore area of RG-2 tumors was estimated at 7.4 x 10(-6) cm(2) g(-1) from fenestrations and 3.5 x 10(-5) cm(2) g(-1) from endothelial gaps. Increased permeability of RG-2 microvessels to macromolecules is most likely attributable to endothelial gaps. Three microvessel populations may occur in brain tumors: (1) continuous nonfenestrated, (2) continuous fenestrated, and (3) discontinuous (with or without fenestrations). The first group may be unique to brain tumors; the latter two are similar to microvessels found in systemic tumors. Since structure-function properties of brain tumor microvessels will affect drug delivery, studies of microvessel function should be incorporated into clinical trials of brain tumor therapy, especially those using macromolecules. Copyright 1999 Academic Press.

Experimental models of demyelination and remyelination.

Science.gov (United States)

Torre-Fuentes, L; Moreno-Jiménez, L; Pytel, V; Matías-Guiu, J A; Gómez-Pinedo, U; Matías-Guiu, J

2017-08-29

Experimental animal models constitute a useful tool to deepen our knowledge of central nervous system disorders. In the case of multiple sclerosis, however, there is no such specific model able to provide an overview of the disease; multiple models covering the different pathophysiological features of the disease are therefore necessary. We reviewed the different in vitro and in vivo experimental models used in multiple sclerosis research. Concerning in vitro models, we analysed cell cultures and slice models. As for in vivo models, we examined such models of autoimmunity and inflammation as experimental allergic encephalitis in different animals and virus-induced demyelinating diseases. Furthermore, we analysed models of demyelination and remyelination, including chemical lesions caused by cuprizone, lysolecithin, and ethidium bromide; zebrafish; and transgenic models. Experimental models provide a deeper understanding of the different pathogenic mechanisms involved in multiple sclerosis. Choosing one model or another depends on the specific aims of the study. Copyright © 2017 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

Modified model of VX2 tumor overexpressing vascular endothelial growth factor.

Science.gov (United States)

Pascale, Florentina; Ghegediban, Saida-Homayra; Bonneau, Michel; Bedouet, Laurent; Namur, Julien; Verret, Valentin; Schwartz-Cornil, Isabelle; Wassef, Michel; Laurent, Alexandre

2012-06-01

To determine whether upregulated expression of vascular endothelial growth factor (VEGF) in VX2 cells can increase vessel density (VD) and reduce tumor necrosis. The VX2 cell line was transfected with expression vectors containing cDNA for rabbit VEGF. Stable clones producing rabbit VEGF (VEGF-VX2) were selected. VEGF-VX2 cells (n = 5 rabbits) or nontransfected VX2 cells (controls; n = 5 rabbits) were implanted into leg muscle of 10 rabbits. The animals were sacrificed at day 21. Tumor volume, percentage of necrosis, VD, and VEGF concentration in tumor protein extract were quantified. Overexpression of VEGF by VX2 cells augmented tumor implantation efficiency 100% and favored cyst formation. The tumor volume was significantly larger for VEGF-VX2 transfected tumors versus controls (P = .0143). Overexpression of VEGF in VX2 cells significantly increased the VD of the tumors (P = .0138). The percentage of necrosis was reduced in VEGF-VX2 tumors versus controls (19.5% vs 38.5 %; P = .002). VEGF concentration in VEGF-VX2 tumors was significantly higher than in control tumors (P = .041) and was correlated with tumor volume (ρ = .883, P = .012). The overexpression of VEGF increased tumor growth and vascularization, favored cyst formation, and reduced tumor necrosis. This new phenotype of the VX2 tumor may offer some advantages over classic models of VX2 tumor for evaluating anticancer therapies. Copyright © 2012 SIR. Published by Elsevier Inc. All rights reserved.

Sensitivity of tumor motion simulation accuracy to lung biomechanical modeling approaches and parameters

International Nuclear Information System (INIS)

Tehrani, Joubin Nasehi; Wang, Jing; Yang, Yin; Werner, Rene; Lu, Wei; Low, Daniel; Guo, Xiaohu

2015-01-01

Finite element analysis (FEA)-based biomechanical modeling can be used to predict lung respiratory motion. In this technique, elastic models and biomechanical parameters are two important factors that determine modeling accuracy. We systematically evaluated the effects of lung and lung tumor biomechanical modeling approaches and related parameters to improve the accuracy of motion simulation of lung tumor center of mass (TCM) displacements. Experiments were conducted with four-dimensional computed tomography (4D-CT). A Quasi-Newton FEA was performed to simulate lung and related tumor displacements between end-expiration (phase 50%) and other respiration phases (0%, 10%, 20%, 30%, and 40%). Both linear isotropic and non-linear hyperelastic materials, including the neo-Hookean compressible and uncoupled Mooney–Rivlin models, were used to create a finite element model (FEM) of lung and tumors. Lung surface displacement vector fields (SDVFs) were obtained by registering the 50% phase CT to other respiration phases, using the non-rigid demons registration algorithm. The obtained SDVFs were used as lung surface displacement boundary conditions in FEM. The sensitivity of TCM displacement to lung and tumor biomechanical parameters was assessed in eight patients for all three models. Patient-specific optimal parameters were estimated by minimizing the TCM motion simulation errors between phase 50% and phase 0%. The uncoupled Mooney–Rivlin material model showed the highest TCM motion simulation accuracy. The average TCM motion simulation absolute errors for the Mooney–Rivlin material model along left-right, anterior–posterior, and superior–inferior directions were 0.80 mm, 0.86 mm, and 1.51 mm, respectively. The proposed strategy provides a reliable method to estimate patient-specific biomechanical parameters in FEM for lung tumor motion simulation. (paper)

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

Experimental study of anti-tumor activity of direct current

International Nuclear Information System (INIS)

Ito, Hisao; Hashimoto, Shozo

1989-01-01

The anti-tumor activity of direct current combined with radiation was studied. The experiments were performed with fibrosarcomas (FSA, NFSA) syngenetic to C3H mice. Direct current (0.6mA, 120min) alone was effective to reduce the tumor sizes, but could not cure the tumors. When the direct current therapy (DC therapy) was combined with radiation the DC therapy following radiation was more effective than that before radiation. Using TCD 50 assay, the DC therapy enhanced the effect of a single dose of radiation with the dose-modifying factor of 1.2. However, tumor control rates by the combination therapy were more improved at the smaller doses of radiation than at the larger ones. When the single DC therapy (0.6mA, 120min) was applied immediately after the first radiation of fractionated one the combination therapy still showed the enhanced effect. However, both DC therapy and the radiation therapy were divided in three fractions, and the DC therapy (0.6mA, 40min) was applied after each radiation. Tumor growth retardation by the combination therapy was no different from that by radiation alone. This result suggests that there might be a minimum required dose of coulombs to show the effect of the combination therapy. (author)

The Dynamics of Glutathione Species and Ophthalmate Concentrations in Plasma from the VX2 Rabbit Model of Secondary Liver Tumors

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R. Abbas

2011-01-01

Full Text Available Purpose. Available tumor markers have low sensitivity/specificity for the diagnosis of liver tumors. The present study was designed to evaluate the oxidoreductive status of the liver as surrogates of tumor subsistence and growth. Methods. Glutathione species (GSH:GSSG, ophthalmate (OA concentrations, and their turnover were measured in plasma of rabbits (n=6 in their healthy state and in the state of tumor growth after implantation of the VX2 carcinoma in their liver. Tumors were allowed to grow for a period of 14 days when rabbits were sacrificed. Livers were removed and cysteine concentration was measured in liver tissue. Results. Tumor growth was found in 100% of the rabbits. Concentration and labeling of GSH/GSSG were similar in experimental animals before and after tumor implantation and to sham animals. In contrast, OA concentration increased significantly in experimental animals after tumor implantation when compared to same animals prior to tumor implantation and to sham animals (P<.05. The concentration of cysteine, a precursor of GSH, was found to be significantly lower in the liver tissue adjacent to the tumor (P<.05. Conclusion. Disturbances in the oxidoreductive state of livers appear to be a surrogate of early tumor growth.

Using Positron Emission Tomography with [18F]FDG to Predict Tumor Behavior in Experimental Colorectal Cancer

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Bryan M. Burt

2001-01-01

Full Text Available This study investigates the relationship between FDG uptake as determined by positron emission tomography (PET imaging and rates of tumor growth, cellular GLUT1 transporter density, and the activities of hexokinase and glucose-6-phosphatase in a solid tumor implant model. Five different human colorectal xenografts of different growth properties were implanted in athymic rats and evaluated by dynamic 18F-FDG-PET. The phosphorylating and dephosphorylating activities of the key glycolytic enzymes, hexokinase and glucose-6-phosphatase, were measured in these tumor types by spectrophotometric assays and the expression of GLUT1 glucose transporter protein was determined by immunohistochemistry. Correlations among FDG accumulation, hexokinase activity, and tumor doubling time are reported in these colon xenografts. The results indicate that the activity of tumor hexokinase may be a marker of tumor growth rate that can be determined by 18F-FDG-PET imaging. PET scanning may not only be a useful tool for staging patients for extent of disease, but may provide important prognostic information concerning the proliferative rates of malignancies.

Effects of low dose mitomycin C on experimental tumor radiotherapy

International Nuclear Information System (INIS)

Yang Jianzheng; Liang Shuo; Qu Yaqin; Pu Chunji; Zhang Haiying; Wu Zhenfeng; Wang Xianli

2001-01-01

Objective: To evaluate the possibility of low dose mitomycin C(MMC) as an adjunct therapy for radiotherapy. Methods: Change in tumor size tumor-bearing mice was measured. Radioimmunoassay was used to determine immune function of mice. Results: Low dose Mac's pretreatment reduced tumor size more markedly than did radiotherapy only. The immune function in mice given with low dose MMC 12h before radiotherapy was obviously higher than that in mice subjected to radiotherapy only (P<0.05), and was close to that in the tumor-bearing mice before radiotherapy. Conclusion: Low dose MMC could improve the radiotherapy effect. Pretreatment with low dose MMC could obviously improve the immune suppression state in mice caused by radiotherapy. The mechanism of its improvement of radiotherapeutic effect by low dose of MMC might be due to its enhancement of immune function and induction of adaptive response in tumor-bearing mice

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....

Sensitivity of Tumor Motion Simulation Accuracy to Lung Biomechanical Modeling Approaches and Parameters

OpenAIRE

Tehrani, Joubin Nasehi; Yang, Yin; Werner, Rene; Lu, Wei; Low, Daniel; Guo, Xiaohu; Wang, Jing

2015-01-01

Finite element analysis (FEA)-based biomechanical modeling can be used to predict lung respiratory motion. In this technique, elastic models and biomechanical parameters are two important factors that determine modeling accuracy. We systematically evaluated the effects of lung and lung tumor biomechanical modeling approaches and related parameters to improve the accuracy of motion simulation of lung tumor center of mass (TCM) displacements. Experiments were conducted with four-dimensional com...

View-Angle Tilting and Slice-Encoding Metal Artifact Correction for Artifact Reduction in MRI: Experimental Sequence Optimization for Orthopaedic Tumor Endoprostheses and Clinical Application.

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Pia M Jungmann

Full Text Available MRI plays a major role in follow-up of patients with malignant bone tumors. However, after limb salvage surgery, orthopaedic tumor endoprostheses might cause significant metal-induced susceptibility artifacts.To evaluate the benefit of view-angle tilting (VAT and slice-encoding metal artifact correction (SEMAC for MRI of large-sized orthopaedic tumor endoprostheses in an experimental model and to demonstrate clinical benefits for assessment of periprosthetic soft tissue abnormalities.In an experimental setting, tumor endoprostheses (n=4 were scanned at 1.5T with three versions of optimized high-bandwidth turbo-spin-echo pulse sequences: (i standard, (ii VAT and (iii combined VAT and SEMAC (VAT&SEMAC. Pulse sequences included coronal short-tau-inversion-recovery (STIR, coronal T1-weighted (w, transverse T1-w and T2-w TSE sequences. For clinical evaluation, VAT&SEMAC was compared to conventional metal artifact-reducing MR sequences (conventional MR in n=25 patients with metal implants and clinical suspicion of tumor recurrence or infection. Diameters of artifacts were measured quantitatively. Qualitative parameters were assessed on a five-point scale (1=best, 5=worst: "image distortion", "artificial signal changes at the edges" and "diagnostic confidence". Imaging findings were correlated with pathology. T-tests and Wilcoxon-signed rank tests were used for statistical analyses.The true size of the prostheses was overestimated on MRI (P<0.05. A significant reduction of artifacts was achieved by VAT (P<0.001 and VAT&SEMAC (P=0.003 compared to the standard group. Quantitative scores improved in the VAT and VAT&SEMAC group (P<0.05. On clinical MR images, artifact diameters were significantly reduced in the VAT&SEMAC-group as compared with the conventional-group (P<0.001. Distortion and artificial signal changes were reduced and diagnostic confidence improved (P<0.05. In two cases, tumor-recurrence, in ten cases infection and in thirteen cases other

Matching the reaction-diffusion simulation to dynamic [18F]FMISO PET measurements in tumors: extension to a flow-limited oxygen-dependent model.

Science.gov (United States)

Shi, Kuangyu; Bayer, Christine; Gaertner, Florian C; Astner, Sabrina T; Wilkens, Jan J; Nüsslin, Fridtjof; Vaupel, Peter; Ziegler, Sibylle I

2017-02-01

Positron-emission tomography (PET) with hypoxia specific tracers provides a noninvasive method to assess the tumor oxygenation status. Reaction-diffusion models have advantages in revealing the quantitative relation between in vivo imaging and the tumor microenvironment. However, there is no quantitative comparison of the simulation results with the real PET measurements yet. The lack of experimental support hampers further applications of computational simulation models. This study aims to compare the simulation results with a preclinical [ 18 F]FMISO PET study and to optimize the reaction-diffusion model accordingly. Nude mice with xenografted human squamous cell carcinomas (CAL33) were investigated with a 2 h dynamic [ 18 F]FMISO PET followed by immunofluorescence staining using the hypoxia marker pimonidazole and the endothelium marker CD 31. A large data pool of tumor time-activity curves (TAC) was simulated for each mouse by feeding the arterial input function (AIF) extracted from experiments into the model with different configurations of the tumor microenvironment. A measured TAC was considered to match a simulated TAC when the difference metric was below a certain, noise-dependent threshold. As an extension to the well-established Kelly model, a flow-limited oxygen-dependent (FLOD) model was developed to improve the matching between measurements and simulations. The matching rate between the simulated TACs of the Kelly model and the mouse PET data ranged from 0 to 28.1% (on average 9.8%). By modifying the Kelly model to an FLOD model, the matching rate between the simulation and the PET measurements could be improved to 41.2-84.8% (on average 64.4%). Using a simulation data pool and a matching strategy, we were able to compare the simulated temporal course of dynamic PET with in vivo measurements. By modifying the Kelly model to a FLOD model, the computational simulation was able to approach the dynamic [ 18 F]FMISO measurements in the investigated

Heterotypic mouse models of canine osteosarcoma recapitulate tumor heterogeneity and biological behavior

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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

Heterotypic mouse models of canine osteosarcoma recapitulate tumor heterogeneity and biological behavior.

Science.gov (United States)

Scott, Milcah C; Tomiyasu, Hirotaka; Garbe, John R; Cornax, Ingrid; Amaya, Clarissa; O'Sullivan, M Gerard; Subramanian, Subbaya; Bryan, Brad A; Modiano, Jaime F

2016-12-01

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 OS. © 2016

Genetic modelling of PIM proteins in cancer: proviral tagging, cooperation with oncogenes, tumor suppressor genes and carcinogens.

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Enara eAguirre

2014-05-01

Full Text Available The PIM proteins, which were initially discovered as proviral insertion sites in Moloney murine leukemia virus infection, are a family of highly homologous serine/threonine kinases that have been reported to be overexpressed in hematological malignancies and solid tumors. The PIM proteins have also been associated with metastasis and overall treatment responses and implicated in the regulation of apoptosis, metabolism, the cell cycle, and homing and migration, which makes these proteins interesting targets for anticancer drug discovery. The use of retroviral insertional mutagenesis and refined approaches such as complementation tagging has allowed the identification of myc, pim and a third group of genes (including bmi1 and gfi1 as complementing genes in lymphomagenesis. Moreover, mouse modeling of human cancer has provided an understanding of the molecular pathways that are involved in tumor initiation and progression at the physiological level. In particular, genetically modified mice have allowed researchers to further elucidate the role of each of the Pim isoforms in various tumor types. PIM kinases have been identified as weak oncogenes because experimental overexpression in lymphoid tissue, prostate and liver induces tumors at a relatively low incidence and with a long latency. However, very strong synergistic tumorigenicity between Pim1/2 and c-Myc and other oncogenes has been observed in lymphoid tissues. Mouse models have also been used to study whether the inhibition of specific PIM isoforms is required to prevent carcinogen-induced sarcomas, indicating that the absence of Pim2 and Pim3 greatly reduces sarcoma growth and bone invasion; the extent of this effect is similar to that observed in the absence of all 3 isoforms. This review will summarize some of the animal models that have been used to understand the isoform-specific contribution of PIM kinases to tumorigenesis.

A biased competition theory of cytotoxic T lymphocyte interaction with tumor nodules.

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Claire Christophe

Full Text Available The dynamics of the interaction between Cytotoxic T Lymphocytes (CTL and tumor cells has been addressed in depth, in particular using numerical simulations. However, stochastic mathematical models that take into account the competitive interaction between CTL and tumors undergoing immunoediting, a process of tumor cell escape from immunesurveillance, are presently missing. Here, we introduce a stochastic dynamical particle interaction model based on experimentally measured parameters that allows to describe CTL function during immunoediting. The model describes the competitive interaction between CTL and melanoma cell nodules and allows temporal and two-dimensional spatial progression. The model is designed to provide probabilistic estimates of tumor eradication through numerical simulations in which tunable parameters influencing CTL efficacy against a tumor nodule undergoing immunoediting are tested. Our model shows that the rate of CTL/tumor nodule productive collisions during the initial time of interaction determines the success of CTL in tumor eradication. It allows efficient cytotoxic function before the tumor cells acquire a substantial resistance to CTL attack, due to mutations stochastically occurring during cell division. Interestingly, a bias in CTL motility inducing a progressive attraction towards a few scout CTL, which have detected the nodule enhances early productive collisions and tumor eradication. Taken together, our results are compatible with a biased competition theory of CTL function in which CTL efficacy against a tumor nodule undergoing immunoediting is strongly dependent on guidance of CTL trajectories by scout siblings. They highlight unprecedented aspects of immune cell behavior that might inspire new CTL-based therapeutic strategies against tumors.

Magnetic resonance characterization of tumor microvessels in experimental breast tumors using a slow clearance blood pool contrast agent (carboxymethyldextran-A2-Gd-DOTA) with histopathological correlation

International Nuclear Information System (INIS)

Preda, Anda; Novikov, Viktor; Moeglich, Martina; Turetschek, Karl; Shames, David M.; Roberts, Timothy P.L.; Brasch, Robert C.; Floyd, Eugenia; Carter, Wayne O.; Corot, Claire

2005-01-01

Carboxymethyldextran (CMD)-A2-Gd-DOTA, a slow clearance blood pool contrast agent with a molecular weight of 52.1 kDa, designed to have intravascular residence for more than 1 h, was evaluated for its potential to characterize and differentiate the microvessels of malignant and benign breast tumors. Precontrast single-slice inversion-recovery snapshot FLASH and dynamic contrast-enhanced MRI using an axial T1-weighted three-dimensional spoiled gradient recalled sequence was performed in 30 Sprague-Dawley rats with chemically induced breast tumors. Endothelial transfer coefficient and fractional plasma volume of the breast tumors were estimated from MRI data acquired with CMD-A2-Gd-DOTA enhancement injected at a dose of 0.1 mmol Gd/kg body weight using a two-compartment bidirectional model of the tumor tissue. The correlation between MRI microvessel characteristics and histopathological tumor grade was determined using the Scarff-Bloom-Richardson method. Using CMD-A2-Gd-DOTA, no significant correlations were found between the MR-estimated endothelial transfer coefficient or plasma volumes with histological tumor grade. Analysis of CMD-A2-Gd-DOTA-enhanced MR kinetic data failed to demonstrate feasibility for the differentiation of benign from malignant tumors or for image-based tumor grading. (orig.)

Modeling triple-negative breast cancer heterogeneity: effects of stromal macrophages, fibroblasts and tumor vasculature.

Science.gov (United States)

Norton, Kerri-Ann; Jin, Kideok; Popel, Aleksander S

2018-05-08

A hallmark of breast tumors is its spatial heterogeneity that includes its distribution of cancer stem cells and progenitor cells, but also heterogeneity in the tumor microenvironment. In this study we focus on the contributions of stromal cells, specifically macrophages, fibroblasts, and endothelial cells on tumor progression. We develop a computational model of triple-negative breast cancer based on our previous work and expand it to include macrophage infiltration, fibroblasts, and angiogenesis. In vitro studies have shown that the secretomes of tumor-educated macrophages and fibroblasts increase both the migration and proliferation rates of triple-negative breast cancer cells. In vivo studies also demonstrated that blocking signaling of selected secreted factors inhibits tumor growth and metastasis in mouse xenograft models. We investigate the influences of increased migration and proliferation rates on tumor growth, the effect of the presence on fibroblasts or macrophages on growth and morphology, and the contributions of macrophage infiltration on tumor growth. We find that while the presence of macrophages increases overall tumor growth, the increase in macrophage infiltration does not substantially increase tumor growth and can even stifle tumor growth at excessive rates. Copyright © 2018. Published by Elsevier Ltd.

Comparative expression analysis reveals lineage relationships between human and murine gliomas and a dominance of glial signatures during tumor propagation in vitro.

Science.gov (United States)

Henriquez, Nico V; Forshew, Tim; Tatevossian, Ruth; Ellis, Matthew; Richard-Loendt, Angela; Rogers, Hazel; Jacques, Thomas S; Reitboeck, Pablo Garcia; Pearce, Kerra; Sheer, Denise; Grundy, Richard G; Brandner, Sebastian

2013-09-15

Brain tumors are thought to originate from stem/progenitor cell populations that acquire specific genetic mutations. Although current preclinical models have relevance to human pathogenesis, most do not recapitulate the histogenesis of the human disease. Recently, a large series of human gliomas and medulloblastomas were analyzed for genetic signatures of prognosis and therapeutic response. Using a mouse model system that generates three distinct types of intrinsic brain tumors, we correlated RNA and protein expression levels with human brain tumors. A combination of genetic mutations and cellular environment during tumor propagation defined the incidence and phenotype of intrinsic murine tumors. Importantly, in vitro passage of cancer stem cells uniformly promoted a glial expression profile in culture and in brain tumors. Gene expression profiling revealed that experimental gliomas corresponded to distinct subclasses of human glioblastoma, whereas experimental supratentorial primitive neuroectodermal tumors (sPNET) correspond to atypical teratoid/rhabdoid tumor (AT/RT), a rare childhood tumor. ©2013 AACR.

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

Leveraging Hypoxia-Activated Prodrugs to Prevent Drug Resistance in Solid Tumors.

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Danika Lindsay

2016-08-01

Full Text Available Experimental studies have shown that one key factor in driving the emergence of drug resistance in solid tumors is tumor hypoxia, which leads to the formation of localized environmental niches where drug-resistant cell populations can evolve and survive. Hypoxia-activated prodrugs (HAPs are compounds designed to penetrate to hypoxic regions of a tumor and release cytotoxic or cytostatic agents; several of these HAPs are currently in clinical trial. However, preliminary results have not shown a survival benefit in several of these trials. We hypothesize that the efficacy of treatments involving these prodrugs depends heavily on identifying the correct treatment schedule, and that mathematical modeling can be used to help design potential therapeutic strategies combining HAPs with standard therapies to achieve long-term tumor control or eradication. We develop this framework in the specific context of EGFR-driven non-small cell lung cancer, which is commonly treated with the tyrosine kinase inhibitor erlotinib. We develop a stochastic mathematical model, parametrized using clinical and experimental data, to explore a spectrum of treatment regimens combining a HAP, evofosfamide, with erlotinib. We design combination toxicity constraint models and optimize treatment strategies over the space of tolerated schedules to identify specific combination schedules that lead to optimal tumor control. We find that (i combining these therapies delays resistance longer than any monotherapy schedule with either evofosfamide or erlotinib alone, (ii sequentially alternating single doses of each drug leads to minimal tumor burden and maximal reduction in probability of developing resistance, and (iii strategies minimizing the length of time after an evofosfamide dose and before erlotinib confer further benefits in reduction of tumor burden. These results provide insights into how hypoxia-activated prodrugs may be used to enhance therapeutic effectiveness in the

A micro-PET/CT approach using O-(2-[{sup 18}F]fluoroethyl)-L-tyrosine in an experimental animal model of F98 glioma for BNCT

Energy Technology Data Exchange (ETDEWEB)

Menichetti, L., E-mail: luca.menichetti@ifc.cnr.it [CNR Institute of Clinical Physiology, Pisa (Italy); Petroni, D.; Panetta, D. [CNR Institute of Clinical Physiology, Pisa (Italy); Burchielli, S. [Fondazione CNR/Regione Toscana G. Monasterio, Pisa (Italy); Bortolussi, Silva [Dept. Theoretical and Nuclear Physics, University of Pavia, Pavia (Italy); Matteucci, M. [Scuola Superiore Sant' Anna, Pisa (Italy); Pascali, G.; Del Turco, S. [CNR Institute of Clinical Physiology, Pisa (Italy); Del Guerra, A. [Department of Physics, University of Pisa, Pisa (Italy); Altieri, S. [Dept. Theoretical and Nuclear Physics, University of Pavia, Pavia (Italy); Salvadori, P.A. [CNR Institute of Clinical Physiology, Pisa (Italy)

2011-12-15

The present study focuses on a micro-PET/CT application to be used for experimental Boron Neutron Capture Therapy (BNCT), which integrates, in the same frame, micro-CT derived anatomy and PET radiotracer distribution. Preliminary results have demonstrated that {sup 18}F-fluoroethyl-tyrosine (FET)/PET allows the identification of the extent of cerebral lesions in F98 tumor bearing rat. Neutron autoradiography and {alpha}-spectrometry on axial tissues slices confirmed the tumor localization and extraction, after the administration of fructose-boronophenylalanine (BPA). Therefore, FET-PET approach can be used to assess the transport, the net influx, and the accumulation of FET, as an aromatic amino acid analog of BPA, in experimental animal model. Coregistered micro-CT images allowed the accurate morphological localization of the radiotracer distribution and its potential use for experimental BNCT.

Tumor trapping of 5-fluorouracil: In vivo 19F NMR spectroscopic pharmacokinetics in tumor-bearing humans and rabbits

International Nuclear Information System (INIS)

Wolf, W.; Servis, K.L.; El-Tahtawy, A.; Singh, M.; Ray, M.; Shani, J.; Presant, C.A.; King, M.; Wiseman, C.; Blayney, D.; Albright, M.J.; Atkinson, D.; Ong, R.; Barker, P.B.; Ring, R. III

1990-01-01

The pharmacokinetics of 5-fluorouracil (5FU) were studied in vivo in patients with discrete tumors and in rabbits bearing VX2 tumors by using 19 F NMR spectroscopy. Free 5FU was detected in the tumors of four of the six patients and in all VX2 tumors but not in normal rabbit tissues. No other metabolites were seen in these tumors, contrary to the extensive catabolism previously documented using 19 F NMR spectroscopy in both human and animal livers. The tumor pool of free 5FU in those human tumors that trapped 5FU was determined to have a half-life of 0.4-2.1 hr, much longer than expected and significantly longer than the half-life of 5FU in blood (5-15 min), whereas the half-life of trapped 5FU in the VX2 tumors ranged from 1.05 to 1.22 hr. These studies document that NMR spectroscopy is clinically feasible in vivo, allows noninvasive pharmacokinetic analyses at a drug-target tissue in real time, and may produce therapeutically important information at the time of drug administration. Demonstration of the trapping of 5FU in tumors provides both a model for studying metabolic modulation in experimental tumors (in animals) and a method for testing modulation strategies clinically (in patients)

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

Experimental model for composite tissue allotransplantations Modelo experimental para alotransplantes de tecido composto

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Lydia Masako Ferreira

2004-12-01

Full Text Available In homologous transplantation or allotranplantation of limbs, the great tissue diversity causes variability in the rejection process and, consequently, its immunology is very complex. Thus, limb transplantation is the most used prototype of compound tissue transplantation among the protocols of experimental studies. Composite tissue allotransplantation represents the experimental model to study the homologous transplantation (from an individual to another of vascularized, innervated musclecutaneous units, joints, bone or even the whole member. Groups of rats were undergone allogeneic hindlimb transplantation. The receptors were randomized and control groups were established as: Control Group A: Autograft controls (F344 rats had its limbs reimplanted and no immunosuppressive therapy. Control Group B: Allograft controls (BN rats limbs were transplanted to F344. Composite tissue homotransplantation allows the inclusion of innervated muscle-cutaneous units, joint and bone or even the hole limb, is considerably applicable in cases of congenital absence or deformity, trauma or greater resection due to malignant tumor. For many complex deformities, these transplantations would allow a more precise reconstruction than the current reconstruction techniques.Nos transplantes alógenos de membro a grande variabilidade de tecidos (pele, subcutâneo, músculo, osso, medula óssea, gânglios linfáticos, cartilagem, nervo, vasos, tendão, articulação leva a grande variação dentro do processo de rejeição e consequentemente a sua imunologia é bastante complexa. Os transplantes alógenos de tecido composto representam o modelo experimental para se estudar o transplante homólogo (de um indivíduo para outro de unidades músculo cutâneas inervadas, vascularizadas, articulações, osso ou mesmo de todo o membro. Os receptores foram randomizados e os grupos controle foram estabelecidos como: grupo controle A: transplante autógeno de membro em que ratos F344

Ultimate dynamics of the Kirschner-Panetta model: Tumor eradication and related problems

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Starkov, Konstantin E.; Krishchenko, Alexander P.

2017-10-01

In this paper we consider the ultimate dynamics of the Kirschner-Panetta model which was created for studying the immune response to tumors under special types of immunotherapy. New ultimate upper bounds for compact invariant sets of this model are given, as well as sufficient conditions for the existence of a positively invariant polytope. We establish three types of conditions for the nonexistence of compact invariant sets in the domain of the tumor-cell population. Our main results are two types of conditions for global tumor elimination depending on the ratio between the proliferation rate of the immune cells and their mortality rate. These conditions are described in terms of simple algebraic inequalities imposed on model parameters and treatment parameters. Our theoretical studies of ultimate dynamics are complemented by numerical simulation results.

Cooperative effects of aminopeptidase N (CD13) expressed by nonmalignant and cancer cells within the tumor microenvironment.

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Guzman-Rojas, Liliana; Rangel, Roberto; Salameh, Ahmad; Edwards, Julianna K; Dondossola, Eleonora; Kim, Yun-Gon; Saghatelian, Alan; Giordano, Ricardo J; Kolonin, Mikhail G; Staquicini, Fernanda I; Koivunen, Erkki; Sidman, Richard L; Arap, Wadih; Pasqualini, Renata

2012-01-31

Processes that promote cancer progression such as angiogenesis require a functional interplay between malignant and nonmalignant cells in the tumor microenvironment. The metalloprotease aminopeptidase N (APN; CD13) is often overexpressed in tumor cells and has been implicated in angiogenesis and cancer progression. Our previous studies of APN-null mice revealed impaired neoangiogenesis in model systems without cancer cells and suggested the hypothesis that APN expressed by nonmalignant cells might promote tumor growth. We tested this hypothesis by comparing the effects of APN deficiency in allografted malignant (tumor) and nonmalignant (host) cells on tumor growth and metastasis in APN-null mice. In two independent tumor graft models, APN activity in both the tumors and the host cells cooperate to promote tumor vascularization and growth. Loss of APN expression by the host and/or the malignant cells also impaired lung metastasis in experimental mouse models. Thus, cooperation in APN expression by both cancer cells and nonmalignant stromal cells within the tumor microenvironment promotes angiogenesis, tumor growth, and metastasis.

Salinomycin nanoparticles interfere with tumor cell growth and the tumor microenvironment in an orthotopic model of pancreatic cancer.

Science.gov (United States)

Daman, Zahra; Faghihi, Homa; Montazeri, Hamed

2018-05-02

Recently, salinomycin (SAL) has been reported to inhibit proliferation and induce apoptosis in various tumors. The aim of this study was to deliver SAL to orthotopic model of pancreatic cancer by the aid of poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs). The NPs were physico-chemically characterized and evaluated for cytotoxicity on luciferase-transduced AsPC-1 cells in vitro as well as implanted orthotopically into the pancreas of nude mice. SAL (3.5 mg/kg every other day) blocked tumor growth by 52% compared to the control group after 3 weeks of therapy. Western blotting of tumor protein extracts indicated that SAL treatment leads to up-regulation of E-cadherin, β-catenin, and transforming growth factor beta receptor (TGFβR) expressions in AsPC-1 orthotopic tumor. Noteworthy, immunofluorescence staining of adjacent tumor sections showed that treatment with SAL NPs cause significant apoptosis in the tumor cells rather than the stroma. Further investigations also revealed that TGFβR2 over-expression was induced in stroma cells after treatment with SAL NPs. These results highlight SAL-loaded PLGA NPs as a promising system for pancreatic cancer treatment, while the mechanistic questions need to be subsequently tested.

Image-based modeling of tumor shrinkage in head and neck radiation therapy1

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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. PMID:20527569

The effect of perioperative analgesic drugs omnopon and dexketoprofen on the functional activity of immune cells in murine model of tumor surgery.

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Sydor, R I; Khranovska, N M; Skachkova, O V; Skivka, L M

2016-01-01

We aimed to investigate the effect of perioperative analgesia with nonselective cyclooxygenase-2 inhibitor dexketoprofen and opioid drug omnopon on the functional activity of immune cells in tumor excision murine model. Lewis lung carcinoma cells were transplanted into hind paw of C57/black mice. On the 23th day tumor was removed. Analgesic drugs were injected 30 min before and once a day for 3 days after the surgery. Biological material was obtained a day before, 1 day and 3 days after the tumor removal. IFN-γ, IL-4, IL-10 and TGF-β mRNA levels in splenic cells were assessed by quantitative real-time RT-PCR. Cytotoxic activity of splenocytes was estimated by flow cytometry. We found that in splenocytes of mice received opioid analgesia IL-10 mRNA level was increased 2.3 times on day one after the surgery compared to preoperative level (P dexketoprofen group this parameter did not change. IFN-γ gene expression level on day 3 after tumor removal was 40% higher in splenocytes of dexketoprofen treated mice as compared with omnopon treated animals (P dexketoprofen against (50.2 ± 3.3)% in omnopon group. In conclusion, perioperative analgesia with cyclooxygenase inhibitor dexketoprofen in contrast to opioid analgesia with omnopon preserves higher functional activity of murine immune cells in the experimental model of tumor surgery.

Transcription factor Runx2 knockdown regulates colon cancer transplantation tumor growth in vitro: an experimental study

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Bin Xu1

2017-05-01

Full Text Available Objective: To study the effect of transcription factor Runx2 knockdown on colon cancer transplantation tumor growth in vitro. Methods: Colon cancer cell lines HT29 were cultured and transfected with negative control (NC - shRNA plasmids and Runx2-shRNA plasmids respectively, the colon cancer cells transfected with shRNA were subcutaneously injected into C57 nude mice, and they were included in NC group and Runx2 knockdown group respectively. 1 week, 2 weeks and 3 weeks after model establishment, serum was collected to determine the contents of tumor markers, and tumor lesions were collected to determine proliferation and apoptosis gene expression. Results: CCSA-2, CEA and CA19-9 levels in serum as well as Rac1, Wnt3a, PLD2 and FAM96B protein expression in transplantation tumor lesions of Runx2 knockdown group were significantly lower than those of NC group while MS4A12, ASPP2 and Fas protein expression in transplantation tumor lesions of Runx2 knockdown group were significantly higher than those of NC group. Conclusion: Transcription factor Runx2 knockdown could inhibit the colon cancer transplantation tumor growth in vitro.

Development of model plans in three dimensional conformal radiotherapy for brain tumors

International Nuclear Information System (INIS)

Pyo, Hongryull; Kim, Gwieon; Keum, Kichang; Chang, Sekyung; Suh, Changok; Lee, Sanghoon

2002-01-01

Three dimensional conformal radiotherapy planning is being used widely for the treatment of patients with brain tumor. However, it takes much time to develop an optimal treatment plan, therefore, it is difficult to apply this technique to all patients. To increase the efficiency of this technique, we need to develop standard radiotherapy plans for each site of the brain. Therefore we developed several 3 dimensional conformal radiotherapy plans (3D plans) for tumors at each site of brain, compared them with each other, and with 2 dimensional radiotherapy plans. Finally model plans for each site of the brain were decided. Imaginary tumors, with sizes commonly observed in the clinic, were designed for each site of the brain and drawn on CT images. The planning target volumes (PTVs) were as follows; temporal tumor-5.7 x 8.2 x 7.6 cm, suprasellar tumor-3 x 4 x 4.1 cm, thalamic tumor-3.1 x 5.9 x 3.7 cm, frontoparietal tumor-5.5 x 7 x 5.5 cm, and occipitoparietal tumor-5 x 5.5 x 5 cm. Plans using parallel opposed 2-portals and/or 3 portals including fronto-vertex and 2 lateral fields were developed manually as the conventional 2D plans, and 3D noncoplanar conformal plans were developed using beam's eye view and the automatic block drawing tool. Total tumor dose was 54 Gy for a suprasellar tumor, 59.4 Gy and 72 Gy for the other tumors. All dose plans (including 2D plans) were calculated using 3D plan software. Developed plans were compared with each other using dose-volume histograms (DVH), normal tissue complication probabilities (NTCP) and variable dose statistic values (minimum, maximum and mean dose, D5, V83, V85 and V95). Finally a best radiotherapy plan for each site of brain was selected. 1) Temporal tumor; NTCPs and DVHs of the normal tissue of all 3D plans were superior to 2D plans and this trend was more definite when total dose was escalated to 72 Gy (NTCPs of normal brain 2D plans: 27%, 8% → 3D plans: 1%, 1%). Various dose statistic values did not show any

Variation in tumor response to fluosol-DA (20%)

International Nuclear Information System (INIS)

Sasai, K.; Ono, K.; Nishidai, T.; Tsutsui, K.; Shibamoto, Y.; Takahashi, M.; Abe, M.

1989-01-01

The effects of Fluosol-DA 20% (FDA) and carbogen (95% O2/5% CO 2 ) on radiosensitivity of the three experimental tumors, SCC VII tumor, RIF-I tumor, and transplanted mammary tumor of C 3 H/He mouse, subcutaneously inoculated in the leg were examined. The effect of FDA plus carbogen, and carbogen alone on radiosensitivity of SCC VII and RIF-I tumors was tested using the in vivo-in vitro assay. The growth curves were obtained for both SCC VII tumor and transplanted mammary tumor. The effect of the combination of FDA and carbogen was only observed in the transplanted mammary tumor. In the other two tumors, only the effect of inspiring carbogen was observed. We concluded that the effect of FDA on the radiosensitivity of experimental tumors varies with the kind of tumor systems

Molecular analysis of radiation-induced experimental tumors in mice

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Niwa, O.; Muto, M.; Suzuki, F.

1992-01-01

Molecular analysis was made on mouse tumors induced by radiation and chemicals. Expression of oncogenes was studied in 12 types of 178 mouse tumors. Southern blotting was done on tumors in which overexpression of oncogenes was noted. Amplification of the myc oncogene was found in chemically induced sarcomas, but not those induced by radiations. Radiogenic thymomas were studied in detail. These thymomas were induced in two different ways. The first was thymomas induced by direct irradiation of F1 mice between C57BL/6NxC3H/He. Southern analysis of DNA revealed deletion of specific minisatellite bands in these tumors. DNA from directly induced thymomas induced focus formation when transfected into normal Golden hamster cells. The mouse K-ras oncogene was detected in these transformants. The second type of thymomas was induced by X-irradiation of thymectomized B10.thy1.2 mice in which normal thymus from congenic B10,thy1.1. mice was grafted. Thymomas of the donor origin was analysed by transfection and the transformants by DNA from those indirectly induced thymomas did not contain activated ras oncogenes. (author)

Interfacial properties in a discrete model for tumor growth

Science.gov (United States)

Moglia, Belén; Guisoni, Nara; Albano, Ezequiel V.

2013-03-01

We propose and study, by means of Monte Carlo numerical simulations, a minimal discrete model for avascular tumor growth, which can also be applied for the description of cell cultures in vitro. The interface of the tumor is self-affine and its width can be characterized by the following exponents: (i) the growth exponent β=0.32(2) that governs the early time regime, (ii) the roughness exponent α=0.49(2) related to the fluctuations in the stationary regime, and (iii) the dynamic exponent z=α/β≃1.49(2), which measures the propagation of correlations in the direction parallel to the interface, e.g., ξ∝t1/z, where ξ is the parallel correlation length. Therefore, the interface belongs to the Kardar-Parisi-Zhang universality class, in agreement with recent experiments of cell cultures in vitro. Furthermore, density profiles of the growing cells are rationalized in terms of traveling waves that are solutions of the Fisher-Kolmogorov equation. In this way, we achieved excellent agreement between the simulation results of the discrete model and the continuous description of the growth front of the culture or tumor.

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

TH-A-BRF-02: BEST IN PHYSICS (JOINT IMAGING-THERAPY) - Modeling Tumor Evolution for Adaptive Radiation Therapy

International Nuclear Information System (INIS)

Liu, Y; Lee, CG; Chan, TCY; Cho, YB; Islam, MK

2014-01-01

Purpose: To develop mathematical models of tumor geometry changes under radiotherapy that may support future adaptive paradigms. Methods: A total of 29 cervical patients were scanned using MRI, once for planning and weekly thereafter for treatment monitoring. Using the tumor volumes contoured by a radiologist, three mathematical models were investigated based on the assumption of a stochastic process of tumor evolution. The “weekly MRI” model predicts tumor geometry for the following week from the last two consecutive MRI scans, based on the voxel transition probability. The other two models use only the first pair of consecutive MRI scans, and the transition probabilities were estimated via tumor type classified from the entire data set. The classification is based on either measuring the tumor volume (the “weekly volume” model), or implementing an auxiliary “Markov chain” model. These models were compared to a constant volume approach that represents the current clinical practice, using various model parameters; e.g., the threshold probability β converts the probability map into a tumor shape (larger threshold implies smaller tumor). Model performance was measured using volume conformity index (VCI), i.e., the union of the actual target and modeled target volume squared divided by product of these two volumes. Results: The “weekly MRI” model outperforms the constant volume model by 26% on average, and by 103% for the worst 10% of cases in terms of VCI under a wide range of β. The “weekly volume” and “Markov chain” models outperform the constant volume model by 20% and 16% on average, respectively. They also perform better than the “weekly MRI” model when β is large. Conclusion: It has been demonstrated that mathematical models can be developed to predict tumor geometry changes for cervical cancer undergoing radiotherapy. The models can potentially support adaptive radiotherapy paradigm by reducing normal tissue dose. This research

TH-A-BRF-02: BEST IN PHYSICS (JOINT IMAGING-THERAPY) - Modeling Tumor Evolution for Adaptive Radiation Therapy

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Liu, Y; Lee, CG [University of Toronto, Toronto, ON (Canada); Chan, TCY [University of Toronto, Toronto, ON (Canada); Techna Institute for the Advancement of Technology for Health, Toronto, ON (Canada); Cho, YB; Islam, MK [University of Toronto, Toronto, ON (Canada); Princess Margaret Hospital, Toronto, ON (Canada); Ontario Consortium for Adaptive Interventions in Radiation Oncology (OCAIRO) (Canada)

2014-06-15

Purpose: To develop mathematical models of tumor geometry changes under radiotherapy that may support future adaptive paradigms. Methods: A total of 29 cervical patients were scanned using MRI, once for planning and weekly thereafter for treatment monitoring. Using the tumor volumes contoured by a radiologist, three mathematical models were investigated based on the assumption of a stochastic process of tumor evolution. The “weekly MRI” model predicts tumor geometry for the following week from the last two consecutive MRI scans, based on the voxel transition probability. The other two models use only the first pair of consecutive MRI scans, and the transition probabilities were estimated via tumor type classified from the entire data set. The classification is based on either measuring the tumor volume (the “weekly volume” model), or implementing an auxiliary “Markov chain” model. These models were compared to a constant volume approach that represents the current clinical practice, using various model parameters; e.g., the threshold probability β converts the probability map into a tumor shape (larger threshold implies smaller tumor). Model performance was measured using volume conformity index (VCI), i.e., the union of the actual target and modeled target volume squared divided by product of these two volumes. Results: The “weekly MRI” model outperforms the constant volume model by 26% on average, and by 103% for the worst 10% of cases in terms of VCI under a wide range of β. The “weekly volume” and “Markov chain” models outperform the constant volume model by 20% and 16% on average, respectively. They also perform better than the “weekly MRI” model when β is large. Conclusion: It has been demonstrated that mathematical models can be developed to predict tumor geometry changes for cervical cancer undergoing radiotherapy. The models can potentially support adaptive radiotherapy paradigm by reducing normal tissue dose. This research

A note on modeling of tumor regression for estimation of radiobiological parameters

International Nuclear Information System (INIS)

Zhong, Hualiang; Chetty, Indrin

2014-01-01

Purpose: Accurate calculation of radiobiological parameters is crucial to predicting radiation treatment response. Modeling differences may have a significant impact on derived parameters. In this study, the authors have integrated two existing models with kinetic differential equations to formulate a new tumor regression model for estimation of radiobiological parameters for individual patients. Methods: A system of differential equations that characterizes the birth-and-death process of tumor cells in radiation treatment was analytically solved. The solution of this system was used to construct an iterative model (Z-model). The model consists of three parameters: tumor doubling time T d , half-life of dead cells T r , and cell survival fraction SF D under dose D. The Jacobian determinant of this model was proposed as a constraint to optimize the three parameters for six head and neck cancer patients. The derived parameters were compared with those generated from the two existing models: Chvetsov's model (C-model) and Lim's model (L-model). The C-model and L-model were optimized with the parameter T d fixed. Results: With the Jacobian-constrained Z-model, the mean of the optimized cell survival fractions is 0.43 ± 0.08, and the half-life of dead cells averaged over the six patients is 17.5 ± 3.2 days. The parameters T r and SF D optimized with the Z-model differ by 1.2% and 20.3% from those optimized with the T d -fixed C-model, and by 32.1% and 112.3% from those optimized with the T d -fixed L-model, respectively. Conclusions: The Z-model was analytically constructed from the differential equations of cell populations that describe changes in the number of different tumor cells during the course of radiation treatment. The Jacobian constraints were proposed to optimize the three radiobiological parameters. The generated model and its optimization method may help develop high-quality treatment regimens for individual patients

Radiation-induced tumors of the nervous system

International Nuclear Information System (INIS)

Bernstein, M.; Laperriere, N.

1991-01-01

Therapeutic and nontherapeutic ionizing radiation has long been recognized as a putative carcinogenic agent, but the evidence that radiation causes tumors is circumstantial at worst and statistically significant at best. There are no distinct histological, biochemical, cytogenetic, or clinical criteria that can be used to determine if an individual tumor was caused directly by previous irradiation of the anatomic area. Additional supportive evidence for radiation-induced tumors includes a position correlation between radiation dose and tumor incidence (usually in the low dose range) and experimental induction of the same neoplasm in appropriate animal models. even if these criteria are fulfilled, coincidental development of a second tumor can never be discounted in an individual patient, particularly if there is an underlying diathesis to develop multiple tumors of different histology, such as in Recklinghausen's disease, or if there is an strong family history for the development of neoplastic disease. In this paper, the authors critically evaluate the available evidence to support the hypothesis that radiation induces tumors in the nervous system. The current concepts of radiation carcinogenesis are discussed and are followed by a discussion of animal data and clinical experience in humans. Finally, a brief discussion on treatment of radiation-induced nervous system tumors is presented

Metabolic 19F MRI an dynamic 18F PET for chemotherapy monitoring in experimental tumors

International Nuclear Information System (INIS)

Brix, G.; Haberkorn, U.; Bellemann, M.E.

1999-01-01

The efficient clinical use of chemotherapeutic agents requires the assessment of the uptake and metabolism of the drugs in the tumor as well as in the various organs of the body by using noninvasive imaging techniques such as magnetic resonance imaging (MRI) and positron emission tomography (PET). In this overview, we present different metabolic 19 F MRI and dynamic 18 F PET techniques for noninvasive monitoring of fluorine-containing anticancer drugs and evaluate their potentials and limitations within the framework of experimental animal studies. (orig.) [de

A tissue-engineered gastric cancer model for mechanistic study of anti-tumor drugs

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Gao, Ming; Cai, Yiting; Wu, Wei; Shi, Yazhou; Fei, Zhewei

2013-01-01

The use of the traditional xenograft subcutaneous tumor model has been contested because of its limitations, such as a slow tumorigenesis, inconsistent chemotherapeutic results, etc. In light of these challenges, we aim to revamp the traditional model by employing an electrospun scaffold composed of polydioxanone, gelatin and elastin to boost the tumorigenesis. The scaffold featured a highly porous microstructure and successfully supported the growth of tumor cells in vitro without provoking apoptosis. In vivo studies showed that in the scaffold model the tumor volume increased by 43.27% and the weight by 75.58%, respectively, within a 12-week period. In addition, the scaffold model saw an increase of CD24 + and CD44 + cells in the tumor mass by 42% and 313%, respectively. The scaffolding materials did not lead to phenotypic changes during the tumorigenesis. Thereafter, in the scaffold model, we found that the chemotherapeutic regimen of docetaxel, cisplatin and fluorouracil unleashed a stronger capability than the regimen comprising cisplatin and fluorouracil to deplete the CD44 + subpopulation. This discovery sheds mechanistic lights on the role of docetaxel for its future chemotherapeutic applications. This revamped model affords cancer scientists a convenient and reliable platform to mechanistically investigate the chemotherapeutic drugs on gastric cancer stem cells. (paper)

Oxygen tension measurements of tumors growing in mice

International Nuclear Information System (INIS)

Adam, Markus F.; Dorie, Mary Jo; Brown, J. Martin

1999-01-01

Purpose: Clinical studies using the Eppendorf histograph have shown that patients whose tumors have a low pO 2 have worse local control after radiotherapy, and have higher metastatic rates. Because preclinical studies of methods of overcoming, or exploiting, hypoxia generally use transplanted tumors in mice, we have compared the oxygenation of mouse tumors with human tumors to determine the appropriateness of the transplanted mouse model for such preclinical studies. Methods and Materials: We evaluated the oxygenation status of subcutaneous (s.c.) tissue and of 12 intradermally (i.d.)- and 7 s.c.-growing mouse or human transplanted tumors in mice using the Eppendorf histograph, and compared the values obtained with measurements of human head and neck nodes. Results: The normal tissue pO 2 profile of air-breathing mice showed a nearly Gaussian distribution (38.2 ± 14.9 mmHg). Breathing 10% O 2 or carbogen resulted in dramatic changes in normal tissue oxygenation. Tumors growing intradermally in the back of air-breathing mice were extremely hypoxic and resistant to expected changes in oxygenation (carbogen breathing, size, and use of anesthetics). Tumors growing s.c. in the foot showed higher oxygen profiles with marked changes in oxygenation when exposing the animals to different levels of oxygen. However, the oxygenation of the mouse tumors transplanted in either site was only a fraction of that of the majority of human tumors. Conclusion: Experimental mouse tumors are markedly hypoxic, with median values of 10-20% of those of human tumors. Hence, mouse tumors are probably good models for the most hypoxic human tumors that respond poorly to radiotherapy; however, caution has to be exercised in extrapolating data from mouse to man

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.

Anti-inflammatory activity of methyl palmitate and ethyl palmitate in different experimental rat models

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Saeed, Noha M. [Department of Pharmacology and Toxicology, Faculty of Pharmacy, Egyptian Russian University, Cairo (Egypt); El-Demerdash, Ebtehal [Department of Pharmacology and Toxicology, Faculty of Pharmacy, Ain Shams University, Cairo (Egypt); Abdel-Rahman, Hanaa M. [Department of Pharmacology and Toxicology, Faculty of Pharmacy, Egyptian Russian University, Cairo (Egypt); Algandaby, Mardi M. [Department of Biology (Botany), Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia); Al-Abbasi, Fahad A. [Department of Biochemistry, Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia); Abdel-Naim, Ashraf B., E-mail: abnaim@pharma.asu.edu.eg [Department of Pharmacology and Toxicology, Faculty of Pharmacy, Ain Shams University, Cairo (Egypt)

2012-10-01

Methyl palmitate (MP) and ethyl palmitate (EP) are naturally occurring fatty acid esters reported as inflammatory cell inhibitors. In the current study, the potential anti-inflammatory activity of MP and EP was evaluated in different experimental rat models. Results showed that MP and EP caused reduction of carrageenan-induced rat paw edema in addition to diminishing prostaglandin E2 (PGE2) level in the inflammatory exudates. In lipopolysaccharide (LPS)-induced endotoxemia in rats, MP and EP reduced plasma levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). MP and EP decreased NF-κB expression in liver and lung tissues and ameliorated histopathological changes caused by LPS. Topical application of MP and EP reduced ear edema induced by croton oil in rats. In the same animal model, MP and EP reduced neutrophil infiltration, as indicated by decreased myeloperoxidase (MPO) activity. In conclusion, this study demonstrates the effectiveness of MP and EP in combating inflammation in several experimental models. -- Highlights: ► Efficacy of MP and EP in combating inflammation was displayed in several models. ► MP and EP reduced carrageenan-induced rat paw edema and prostaglandin E2 level. ► MP and EP decreased TNF-α and IL-6 levels in experimental endotoxemia. ► MP and EP reduced NF-κB expression and histological changes in rat liver and lung. ► MP and EP reduced croton oil-induced ear edema and neutrophil infiltration.

In ovo method for evaluating the effect of nutritional therapies on tumor development, growth and vascularization

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Yves M. Dupertuis

2015-10-01

Full Text Available In the state of the art evaluation of nutritional therapy on tumor development, growth and vascularization requires tedious and expensive in vivo assays in which a significant number of animals undergo invasive treatments. Therefore, new alternative methods to avoid animal suffering and sacrifice are welcome. This review presents a rapid and low-cost method of experimental radio/chemotherapy in tumor xenografted chicken chorioallantoic membrane (CAM, which may contribute to implement the 3R principle (Reduce, Refine, Replace. Advantages and limitations of the CAM as an experimental model in cancer research are discussed. Improving the CAM model by using tumor spheroid grafting and positron emission and computed tomography imaging would help to overcome the drawbacks of poor tumor grafting efficiency and restrained 2-D tumor growth measurement to the CAM surface. Such a simple, reliable, reproducible and quantitative method for obtaining dose–response analysis and estimating treatment schedule (i.e. type, route, dose and timing would provide an alternative to the time-consuming and expensive evaluation step in animals before initiating clinical trials.

Modified Gompertz equation for electrotherapy murine tumor growth kinetics: predictions and new hypotheses

International Nuclear Information System (INIS)

Cabrales, Luis E Bergues; Mateus, Miguel A O'Farril; Brooks, Soraida C Acosta; Palencia, Fabiola Suárez; Zamora, Lisset Ortiz; Quevedo, María C Céspedes; Seringe, Sarah Edward; Cuitié, Vladimir Crombet; Cabrales, Idelisa Bergues; González, Gustavo Sierra; Nava, Juan J Godina; Aguilera, Andrés Ramírez; Joa, Javier A González; Ciria, Héctor M Camué; González, Maraelys Morales; Salas, Miriam Fariñas; Jarque, Manuel Verdecia; González, Tamara Rubio

2010-01-01

Electrotherapy effectiveness at different doses has been demonstrated in preclinical and clinical studies; however, several aspects that occur in the tumor growth kinetics before and after treatment have not yet been revealed. Mathematical modeling is a useful instrument that can reveal some of these aspects. The aim of this paper is to describe the complete growth kinetics of unperturbed and perturbed tumors through use of the modified Gompertz equation in order to generate useful insight into the mechanisms that underpin this devastating disease. The complete tumor growth kinetics for control and treated groups are obtained by interpolation and extrapolation methods with different time steps, using experimental data of fibrosarcoma Sa-37. In the modified Gompertz equation, a delay time is introduced to describe the tumor's natural history before treatment. Different graphical strategies are used in order to reveal new information in the complete kinetics of this tumor type. The first stage of complete tumor growth kinetics is highly non linear. The model, at this stage, shows different aspects that agree with those reported theoretically and experimentally. Tumor reversibility and the proportionality between regions before and after electrotherapy are demonstrated. In tumors that reach partial remission, two antagonistic post-treatment processes are induced, whereas in complete remission, two unknown antitumor mechanisms are induced. The modified Gompertz equation is likely to lead to insights within cancer research. Such insights hold promise for increasing our understanding of tumors as self-organizing systems and, the possible existence of phase transitions in tumor growth kinetics, which, in turn, may have significant impacts both on cancer research and on clinical practice

Experimentally induced tumors used for angiographic estimation of embolisation and cytostatic treatment

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Strecker, E P; Kraus, W; Fiebig, H H; Kauffmann, G; Hauenstein, K H

1982-02-01

In 12 rats tumors have been induced chemically by intraperitoneal application of dimethylnitrosamine. This method is simple and reliable and the effect of tumor embolization can be followed easily. Thymus aplastic nude mice with transplanted human tumors deserve strict care. Tumor microangiograms of 48 animals demonstrate a close similarity with angiograms of corresponding human tumors. The vascular pattern does not alterate after several transplantations, after cytostatic therapy a slight hypervascularisation developes.

Effect of x irradiation on the vascularization of experimental animal tumors

Energy Technology Data Exchange (ETDEWEB)

Saeki, Y; Ogawa, F; Nishiguchi, H; Tanaka, N; Murakami, K [Kyoto Prefectural Univ. of Medicine (Japan)

1975-03-01

The authors studied the effect of ionizing radiation on blood vessels and tumor growth in two animal tumor systems: a third generation isoplants of a mammary cancer and a spontaneously arising squamous cell carcinoma. Single cell suspensions were transplanted into a C3H and a C3Hf mouse respectively. They were irradiated once with 2000 rad when the tumors reached about 8 mm in diameter. Microangiography was performed at a constant temperature and pressure, and a contrast medium containing lead-oxide and gelatin was flushed the vena cava for 10 min. at 120 mmHg. Tumor shrinkage was followed by continuous regrowth. The basic vasculature of the mammary carcinoma consisted of abundant large and fine blood vessels corkscrewed or stretched from the periphery of the tumor to its center in complex reticular networks. One day after irradiation there were small scattered avascular areas which, by the third day formed a large central necrosis. Supervascularization was also observed, indicating that some hypoxic tumor cells could be reoxygenized. In 5 days vascularization was similar to that of a nonirradiated tumor. Conversely, The squamous cell carcinoma showed peripheral and central vascularization with abundant vascular and avascular areas and extravasion in the large avascular area. Two days after irradiation the vessels were dilated. At 3 days peripheral fine vessels were damaged but the central vasculature remained intact. Unlike the mammary carcinoma, supervascularization was not the typical finding. At 5 days, vascularization was similar to that of a nonirradiated tumor.

Tumor-Associated Macrophages as Major Players in the Tumor Microenvironment

International Nuclear Information System (INIS)

Chanmee, Theerawut; Ontong, Pawared; Konno, Kenjiro; Itano, Naoki

2014-01-01

During tumor progression, circulating monocytes and macrophages are actively recruited into tumors where they alter the tumor microenvironment to accelerate tumor progression. Macrophages shift their functional phenotypes in response to various microenvironmental signals generated from tumor and stromal cells. Based on their function, macrophages are divided broadly into two categories: classical M1 and alternative M2 macrophages. The M1 macrophage is involved in the inflammatory response, pathogen clearance, and antitumor immunity. In contrast, the M2 macrophage influences an anti-inflammatory response, wound healing, and pro-tumorigenic properties. Tumor-associated macrophages (TAMs) closely resemble the M2-polarized macrophages and are critical modulators of the tumor microenvironment. Clinicopathological studies have suggested that TAM accumulation in tumors correlates with a poor clinical outcome. Consistent with that evidence, experimental and animal studies have supported the notion that TAMs can provide a favorable microenvironment to promote tumor development and progression. In this review article, we present an overview of mechanisms responsible for TAM recruitment and highlight the roles of TAMs in the regulation of tumor angiogenesis, invasion, metastasis, immunosuppression, and chemotherapeutic resistance. Finally, we discuss TAM-targeting therapy as a promising novel strategy for an indirect cancer therapy

Tumor-Associated Macrophages as Major Players in the Tumor Microenvironment

Energy Technology Data Exchange (ETDEWEB)

Chanmee, Theerawut [Institute of Advanced Technology, Kyoto Sangyo University, Kita-ku, Kyoto 603-8555 (Japan); Ontong, Pawared [Division of Engineering (Biotechnology), Graduate School of Engineering, Kyoto Sangyo University, Kita-ku, Kyoto 603-8555 (Japan); Konno, Kenjiro [Department of Animal Medical Sciences, Faculty of Life Sciences, Kyoto Sangyo University, Kita-ku, Kyoto 603-8555 (Japan); Itano, Naoki, E-mail: itanon@cc.kyoto-su.ac.jp [Institute of Advanced Technology, Kyoto Sangyo University, Kita-ku, Kyoto 603-8555 (Japan); Division of Engineering (Biotechnology), Graduate School of Engineering, Kyoto Sangyo University, Kita-ku, Kyoto 603-8555 (Japan); Department of Molecular Biosciences, Faculty of Life Sciences, Kyoto Sangyo University, Kita-ku, Kyoto 603-8555 (Japan)

2014-08-13

During tumor progression, circulating monocytes and macrophages are actively recruited into tumors where they alter the tumor microenvironment to accelerate tumor progression. Macrophages shift their functional phenotypes in response to various microenvironmental signals generated from tumor and stromal cells. Based on their function, macrophages are divided broadly into two categories: classical M1 and alternative M2 macrophages. The M1 macrophage is involved in the inflammatory response, pathogen clearance, and antitumor immunity. In contrast, the M2 macrophage influences an anti-inflammatory response, wound healing, and pro-tumorigenic properties. Tumor-associated macrophages (TAMs) closely resemble the M2-polarized macrophages and are critical modulators of the tumor microenvironment. Clinicopathological studies have suggested that TAM accumulation in tumors correlates with a poor clinical outcome. Consistent with that evidence, experimental and animal studies have supported the notion that TAMs can provide a favorable microenvironment to promote tumor development and progression. In this review article, we present an overview of mechanisms responsible for TAM recruitment and highlight the roles of TAMs in the regulation of tumor angiogenesis, invasion, metastasis, immunosuppression, and chemotherapeutic resistance. Finally, we discuss TAM-targeting therapy as a promising novel strategy for an indirect cancer therapy.

Vascular Targeting in Pancreatic Cancer: The Novel Tubulin-Binding Agent ZD6126 Reveals Antitumor Activity in Primary and Metastatic Tumor Models

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Axel Kleespies

2005-10-01

Full Text Available ZD6126 is a novel vascular-targeting agent that acts by disrupting the tubulin cytoskeleton of an immature tumor endothelium, leading to an occlusion of tumor blood vessels and a subsequent tumor necrosis. We wanted to evaluate ZD6126 in primary and metastatic tumor models of human pancreatic cancer. Nude mice were injected orthotopically with L3.6pl pancreatic cancer cells. In single and multiple dosing experiments, mice received ZD6126, gemcitabine, a combination of both agents, or no treatment. For the induction of metastatic disease, additional groups of mice were injected with L3.6pl cells into the spleen. Twenty-four hours after a single-dose treatment, ZD6126 therapy led to an extensive central tumor necrosis, which was not seen after gemcitabine treatment. Multiple dosing of ZD6126 resulted in a significant growth inhibition of primary tumors and a marked reduction of spontaneous liver and lymph node metastases. Experimental metastatic disease could be significantly controlled by a combination of ZD6126 and gemcitabine, as shown by a reduction of the number and size of established liver metastases. As shown by additional in vitro and in vivo experiments, possible mechanisms involve antivascular activities and subsequent antiproliferative and proapoptotic effects of ZD6126 on tumor cells, whereas direct activities against tumor cells seem unlikely. These data highlight the antitumor and antimetastatic effects of ZD6126 in human pancreatic cancer and reveal benefits of adding ZD6126 to standard gemcitabine therapy.

Combined calcitriol and menadione reduces experimental murine triple negative breast tumor.

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Bohl, Luciana; Guizzardi, Solange; Rodríguez, Valeria; Hinrichsen, Lucila; Rozados, Viviana; Cremonezzi, David; Tolosa de Talamoni, Nori; Picotto, Gabriela

2017-10-01

Calcitriol (D) or 1,25(OH) 2 D 3 inhibits the growth of several tumor cells including breast cancer cells, by activating cell death pathways. Menadione (MEN), a glutathione-depleting compound, may be used to potentiate the antiproliferative actions of D on cancer cells. We have previously shown in vitro that MEN improved D-induced growth arrest on breast cancer cell lines, inducing oxidative stress and DNA damage via ROS generation. Treatment with MEN+D resulted more effective than D or MEN alone. To study the in vivo effect of calcitriol, MEN or their combination on the development of murine transplantable triple negative breast tumor M-406 in its syngeneic host. Tumor M-406 was inoculated s.c., and when tumors reached the desired size, animals were randomly assigned to one of four groups receiving daily i.p. injections of either sterile saline solution (controls, C), MEN, D, or both (MEN+D). Body weight and tumor volume were recorded three times a week. Serum calcium was determined before and at the end of the treatment, at which time tumor samples were obtained for histological examination. None of the drugs, alone or in combination, affected mice body weight in the period studied. The combined treatment reduced tumor growth rate (C vs. MEN+D, P<0.05) and the corresponding histological sections exhibited small remaining areas of viable tumor only in the periphery. A concomitant DNA fragmentation was observed in all treated groups and MEN potentiated the calcitriol effect on tumor growth. As previously observed in vitro, treatment with MEN and D delayed tumor growth in vivo more efficiently than the individual drugs, with evident signals of apoptosis induction. Our results propose an alternative protocol to treat triple negative breast cancer, using GSH depleting drugs together with calcitriol, which would allow lower doses of the steroid to maintain the antitumor effect while diminishing its adverse pharmacological effects. Copyright © 2017. Published by

Preliminary study of MR diffusion weighted imaging in nude mice models of hepatic Bel7402 tumors after adenovirus-mediated cytosine diaminase-thymidine kinase gene therapy

International Nuclear Information System (INIS)

Jiang Xinqing; Chen Liang; Wu Hongzhen; Huang Jingjun; Wei Xinhua; Mo Lei; Yang Ruimeng; Xiao Xiangsheng

2012-01-01

Objective: To study the characteristics of DWI in nude mice models of hepatic Bel7402 tumors after treatment with adenovirus-mediated cytosine diaminase-thymidine kinase (Ad. CD-TK) double suicide gene therapy, and then to identify whether DWI can be used for assessing curative effect of postoperative tumors. Methods: Thirty nude mice models of hepatic Bel7402 tumors were successfully created using cell suspension method, after the tumor grew to more than 1 cm in diameter, 20 tumor models were treated by intratumoral administration of Ad. CD-TK for 3 days plus intraperitonea (i.p.) treatment with 5-Fc and GCV for the duration of the study.Then they were randomly divided into three groups during 5-Fc and GCV treatment. The remaining 10 tumor models were used as controls. MR scanning were performed in 10 th day before and after tumor implantation in all models by using EPI-SE series and SENSE technology for treatment group. Tumor volumes and ADC values were calculated pretreatment and posttreatment. Cell apoptosis were determined by using TUNEL method. Analyze the change of ADC and apoptosis index (AI) in different times, t test was used for comparison the difference of AI and ADC values respectively. Results: After 10 days,the tumor volumes of the treatment groups and controls were respectively (724.16 ±57.45) mm 3 , (754.57 ± 66.84) mm 3 , with no significant difference (t=0.488, P >0.05). The ADC values of the treatment groups were (0.98 ±0.11) × 10 -3 mm 2 /s,the ones of the control groups were (0.68 ±0.04) × 10 -3 mm 2 /s; AI of the treatment groups were (23.25 ±6.57)%, the ones of the control groups were (2.57 ± 0.58)%. There were difference in both groups (t=4.473, 5.874; P<0.01). Conclusion: DWI can be effectively to monitor the early pathological changes of hepatic Bel7402 tumors after Ad. CD-TK double suicide gene therapy, and provide experimental evidences for clinical application. (authors)

Tumor-Volume Simulation During Radiotherapy for Head-and-Neck Cancer Using a Four-Level Cell Population Model

International Nuclear Information System (INIS)

Chvetsov, Alexei V.; Dong Lei; Palta, Jantinder R.; Amdur, Robert J.

2009-01-01

Purpose: To develop a fast computational radiobiologic model for quantitative analysis of tumor volume during fractionated radiotherapy. The tumor-volume model can be useful for optimizing image-guidance protocols and four-dimensional treatment simulations in proton therapy that is highly sensitive to physiologic changes. Methods: The analysis is performed using two approximations: (1) tumor volume is a linear function of total cell number and (2) tumor-cell population is separated into four subpopulations: oxygenated viable cells, oxygenated lethally damaged cells, hypoxic viable cells, and hypoxic lethally damaged cells. An exponential decay model is used for disintegration and removal of oxygenated lethally damaged cells from the tumor. Results: We tested our model on daily volumetric imaging data available for 14 head-and-neck cancer patients treated with an integrated computed tomography/linear accelerator system. A simulation based on the averaged values of radiobiologic parameters was able to describe eight cases during the entire treatment and four cases partially (50% of treatment time) with a maximum 20% error. The largest discrepancies between the model and clinical data were obtained for small tumors, which may be explained by larger errors in the manual tumor volume delineation procedure. Conclusions: Our results indicate that the change in gross tumor volume for head-and-neck cancer can be adequately described by a relatively simple radiobiologic model. In future research, we propose to study the variation of model parameters by fitting to clinical data for a cohort of patients with head-and-neck cancer and other tumors. The potential impact of other processes, like concurrent chemotherapy, on tumor volume should be evaluated.

The combination of IL-21 and IFN-alpha boosts STAT3 activation, cytotoxicity and experimental tumor therapy

DEFF Research Database (Denmark)

Eriksen, Karsten W; Søndergaard, Henrik; Woetmann, Anders

2008-01-01

such as IFN-alpha and IL-2 have multiple and severe side effects. Accordingly, they are generally used at sub-optimal doses, which limit their clinical efficacy. Here we hypothesized that a combination of IFN-alpha and IL-21, a novel cytokine of the IL-2 family with anti-cancer effects, will increase the anti......-cancer efficacy at sub-optimal cytokine doses. We show that the combined stimulation of target-cells with IFN-alpha and IL-21 triggers an increased STAT3 activation whereas the activation of other STATs including STAT1/2 is unaffected. In parallel, the combined stimulation with IFN-alpha and IL-21 triggers...... a selective increase in MHC class I expression and NK- and CD8(+) T-cell-mediated cytotoxicity. In an experimental in vivo model of renal carcinoma, the combined treatment of IFN-alpha and IL-21 also produces a significant anti-cancer effect as judged by an inhibition of tumor growth and an increased survival...

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

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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.

Three-dimensional printing of Hela cells for cervical tumor model in vitro

International Nuclear Information System (INIS)

Zhao, Yu; Yao, Rui; Ouyang, Liliang; Ding, Hongxu; Zhang, Ting; Sun, Wei; Zhang, Kaitai; Cheng, Shujun

2014-01-01

Advances in three-dimensional (3D) printing have enabled the direct assembly of cells and extracellular matrix materials to form in vitro cellular models for 3D biology, the study of disease pathogenesis and new drug discovery. In this study, we report a method of 3D printing for Hela cells and gelatin/alginate/fibrinogen hydrogels to construct in vitro cervical tumor models. Cell proliferation, matrix metalloproteinase (MMP) protein expression and chemoresistance were measured in the printed 3D cervical tumor models and compared with conventional 2D planar culture models. Over 90% cell viability was observed using the defined printing process. Comparisons of 3D and 2D results revealed that Hela cells showed a higher proliferation rate in the printed 3D environment and tended to form cellular spheroids, but formed monolayer cell sheets in 2D culture. Hela cells in 3D printed models also showed higher MMP protein expression and higher chemoresistance than those in 2D culture. These new biological characteristics from the printed 3D tumor models in vitro as well as the novel 3D cell printing technology may help the evolution of 3D cancer study. (paper)

A deterministic and stochastic model for the system dynamics of tumor-immune responses to chemotherapy

Science.gov (United States)

Liu, Xiangdong; Li, Qingze; Pan, Jianxin

2018-06-01

Modern medical studies show that chemotherapy can help most cancer patients, especially for those diagnosed early, to stabilize their disease conditions from months to years, which means the population of tumor cells remained nearly unchanged in quite a long time after fighting against immune system and drugs. In order to better understand the dynamics of tumor-immune responses under chemotherapy, deterministic and stochastic differential equation models are constructed to characterize the dynamical change of tumor cells and immune cells in this paper. The basic dynamical properties, such as boundedness, existence and stability of equilibrium points, are investigated in the deterministic model. Extended stochastic models include stochastic differential equations (SDEs) model and continuous-time Markov chain (CTMC) model, which accounts for the variability in cellular reproduction, growth and death, interspecific competitions, and immune response to chemotherapy. The CTMC model is harnessed to estimate the extinction probability of tumor cells. Numerical simulations are performed, which confirms the obtained theoretical results.

In vitro microfluidic models of tumor microenvironment to screen transport of drugs and nanoparticles.

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Ozcelikkale, Altug; Moon, Hye-Ran; Linnes, Michael; Han, Bumsoo

2017-09-01

Advances in nanotechnology have enabled numerous types of nanoparticles (NPs) to improve drug delivery to tumors. While many NP systems have been proposed, their clinical translation has been less than anticipated primarily due to failure of current preclinical evaluation techniques to adequately model the complex interactions between the NP and physiological barriers of tumor microenvironment. This review focuses on microfluidic tumor models for characterization of delivery efficacy and toxicity of cancer nanomedicine. Microfluidics offer significant advantages over traditional macroscale cell cultures by enabling recapitulation of tumor microenvironment through precise control of physiological cues such as hydrostatic pressure, shear stress, oxygen, and nutrient gradients. Microfluidic systems have recently started to be adapted for screening of drugs and NPs under physiologically relevant settings. So far the two primary application areas of microfluidics in this area have been high-throughput screening using traditional culture settings such as single cells or multicellular tumor spheroids, and mimicry of tumor microenvironment for study of cancer-related cell-cell and cell-matrix interactions. These microfluidic technologies are also useful in modeling specific steps in NP delivery to tumor and characterize NP transport properties and outcomes by systematic variation of physiological conditions. Ultimately, it will be possible to design drug-screening platforms uniquely tailored for individual patient physiology using microfluidics. These in vitro models can contribute to development of precision medicine by enabling rapid and patient-specific evaluation of cancer nanomedicine. WIREs Nanomed Nanobiotechnol 2017, 9:e1460. doi: 10.1002/wnan.1460 For further resources related to this article, please visit the WIREs website. © 2017 Wiley Periodicals, Inc.

[Study of the immunological mechanism of anti-tumor effects of 5-FU by establishing EL4 tumor-bearing mouse models].

Science.gov (United States)

Li, Mo-Lin; Li, Chuan-Gang; Shu, Xiao-Hong; Li, Ming-Xia; Jia, Yu-Jie; Qin, Zhi-Hai

2007-11-01

To investigate the immunological mechanism of anti-tumor effect of 5-FU by establishing lymphoma EL4 tumor-bearing mouse models in wild type C57BL/6 mice and nude C57BL/6 mice, respectively. The mouse lymphoma EL4 cells were inoculated subcutaneously into wild type C57BL/6 mice (immune-competent mice). Twelve days later, 5-FU of different doses was administered intraperitoneally to treat these wild type C57BL/6 tumor-bearing mice. The size of tumors in the wild type C57BL/6 mice was observed and recorded to explore the minimal dose of 5-FU that could cure the tumor-bearing mice. Then the same amount of EL4 tumor cells was inoculated subcutaneously into wild type C57BL/6 mice and nude C57BL/6 mice (T cell-deficient mice) simultaneously, which had the same genetic background of C57BL/6. Twelve days later, 5-FU of the minimal dose was given intraperitoneally to treat both the wild type and nude C57BL/6 tumor-bearing mice. The size of tumors in the two different types of mice was observed and recorded. A single dose of 5-FU (75 mg/kg) cured both the EL4 tumor-bearing wild type C57BL/6 mice and the EL4 tumor-bearing nude C57BL/6 mice in the first week. Two weeks after 5-FU treatment, all of the nude mice died of tumor relapse while most of the wild type C57BL/6 mice were fully recovered. A single dose of 5-FU has marked anti-tumor effects on lymphoma EL4 tumor-bearing C57BL/6 mice with or without T lymphocytes. The relapse of tumors after 5-FU treatment might be related to the function of T lymphocytes.

A state-based probabilistic model for tumor respiratory motion prediction

International Nuclear Information System (INIS)

Kalet, Alan; Sandison, George; Schmitz, Ruth; Wu Huanmei

2010-01-01

This work proposes a new probabilistic mathematical model for predicting tumor motion and position based on a finite state representation using the natural breathing states of exhale, inhale and end of exhale. Tumor motion was broken down into linear breathing states and sequences of states. Breathing state sequences and the observables representing those sequences were analyzed using a hidden Markov model (HMM) to predict the future sequences and new observables. Velocities and other parameters were clustered using a k-means clustering algorithm to associate each state with a set of observables such that a prediction of state also enables a prediction of tumor velocity. A time average model with predictions based on average past state lengths was also computed. State sequences which are known a priori to fit the data were fed into the HMM algorithm to set a theoretical limit of the predictive power of the model. The effectiveness of the presented probabilistic model has been evaluated for gated radiation therapy based on previously tracked tumor motion in four lung cancer patients. Positional prediction accuracy is compared with actual position in terms of the overall RMS errors. Various system delays, ranging from 33 to 1000 ms, were tested. Previous studies have shown duty cycles for latencies of 33 and 200 ms at around 90% and 80%, respectively, for linear, no prediction, Kalman filter and ANN methods as averaged over multiple patients. At 1000 ms, the previously reported duty cycles range from approximately 62% (ANN) down to 34% (no prediction). Average duty cycle for the HMM method was found to be 100% and 91 ± 3% for 33 and 200 ms latency and around 40% for 1000 ms latency in three out of four breathing motion traces. RMS errors were found to be lower than linear and no prediction methods at latencies of 1000 ms. The results show that for system latencies longer than 400 ms, the time average HMM prediction outperforms linear, no prediction, and the more

Treatment schedule of combination using radiation and ACNU in the experimental brain tumors

International Nuclear Information System (INIS)

Kaneko, Sadao; Allen, N.J.; Clendenon, N.R.; Kartha, M.

1983-01-01

This study was undertaken to identify the combined effect of ACNU treatment and irradiation in a rat (CD Fisher) brain tumor model, which was produced by stereotaxic inoculation of F-98 or D-74 glioma clone cells. In the first series using F-98, the median survival time of the controls was 38 days. ACNU alone (7 mg/kg x 3) on Day 5, 6 and 7 following tumor cell inoculation resulted in 45 days, a single dose of irradiation alone (1,500 rads) on Day 8 produced 45 days and the combined treatment resulted in 58 days with a 28.9% increased life span (%ILS). In the second series using D-74, the median survival time of the control group was 20 days. ACNU alone (7 mg/kg x 3) showed no significant increase in survival time. A single dose of irradiation resulted in 23 days and the combined treatment in 26 days with 13.0%ILS. The third series assessed the schedule dependence of the combined treatment effects of ACNU and irradiation using D-74. The median survival time of the controls was 21 days. A single dose of ACNU (20 mg/kg) produced no significant increase. Irradiation alone (1,500 rads) on Day 8 resulted in 26 days. Combined treatment groups receiving ACNU 1 hour and 3 days prior to irradiation showed a significant increase (31 days with 19.2%ILS and 28.5 days with 9.6%ILS, respectively). However, survival times in the groups receiving ACNU 6 or 26 hours prior to irradiation, as well as 6 hours following irradiation, were not significantly longer than those in the group of irradiation alone. No significant difference in tumor size at the time of death was noted among any of the groups. Combined use of ACNU and irradiation may have a synergistic effect on the rat brain tumor model, and this effect depends on the combination schedule. (J.P.N.)

Trastuzumab anti-tumor efficacy in patient-derived esophageal squamous cell carcinoma xenograft (PDECX mouse models

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Wu Xianhua

2012-08-01

Full Text Available Abstract Background Trastuzumab is currently approved for the clinical treatment of breast and gastric cancer patients with HER-2 positive tumors, but not yet for the treatment of esophageal carcinoma patients, whose tumors typically show 5 ~ 35% HER-2 gene amplification and 0 ~ 56% HER-2 protein expression. This study aimed to investigate the therapeutic efficacy of Trastuzumab in patient-derived esophageal squamous cell carcinoma xenograft (PDECX mouse models. Methods PDECX models were established by implanting patient esophageal squamous cell carcinoma (ESCC tissues into immunodeficient (SCID/nude mice. HER-2 gene copy number (GCN and protein expression were determined in xenograft tissues and corresponding patient EC samples by FISH and IHC analysis. Trastuzumab anti-tumor efficacy was evaluated within these PDECX models (n = 8 animals/group. Furthermore, hotspot mutations of EGFR, K-ras, B-raf and PIK3CA genes were screened for in the PDECX models and their corresponding patient’s ESCC tissues. Similarity between the PDECX models and their corresponding patient’s ESCC tissue was confirmed by histology, morphology, HER-2 GCN and mutation. Results None of the PDECX models (or their corresponding patient’s ESCC tissues harbored HER-2 gene amplification. IHC staining showed HER-2 positivity (IHC 2+ in 2 PDECX models and negativity in 3 PDECX models. Significant tumor regression was observed in the Trastuzumab-treated EC044 HER-2 positive model (IHC 2+. A second HER-2 positive (IHC 2+ model, EC039, harbored a known PIK3CA mutation and showed strong activation of the AKT signaling pathway and was insensitive to Trastuzumab treatment, but could be resensitised using a combination of Trastuzumab and AKT inhibitor AZD5363. In summary, we established 5 PDECX mouse models and demonstrated tumor regression in response to Trastuzumab treatment in a HER-2 IHC 2+ model, but resistance in a HER-2 IHC 2+/PIK3CA mutated model. Conclusions

Tumoral fibrosis effect on the radiation absorbed dose of 177Lu–Tyr3-octreotate and 177Lu–Tyr3-octreotate conjugated to gold nanoparticles

International Nuclear Information System (INIS)

Azorín-Vega, E.P.; Zambrano-Ramírez, O.D.; Rojas-Calderón, E.L.; Ocampo-García, B.E.; Ferro-Flores, G.

2015-01-01

The aim of this work was to evaluate the tumoral fibrosis effect on the radiation absorbed dose of the radiopharmaceuticals 177 Lu–Tyr 3 -octreotate (monomeric) and 177 Lu–Tyr 3 -octreotate–gold nanoparticles (multimeric) using an experimental HeLa cells tumoral model and the Monte Carlo PENELOPE code. Experimental and computer micro-environment models with or without fibrosis were constructed. Results showed that fibrosis increases up to 33% the tumor radiation absorbed dose, although the major effect on the dose was produced by the type of radiopharmaceutical (112 Gy-multimeric vs. 43 Gy-monomeric). - Highlights: • Fibrosis increases the radiation absorbed dose to the tumor. • Fibrosis increases the radiopharmaceutical residence time in the tumor. • The multimeric nature of the radiopharmaceuticals enhances the radiopharmaceutical retention

Monitoring of Tumor Growth with [(18)F]-FET PET in a Mouse Model of Glioblastoma: SUV Measurements and Volumetric Approaches.

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Holzgreve, Adrien; Brendel, Matthias; Gu, Song; Carlsen, Janette; Mille, Erik; Böning, Guido; Mastrella, Giorgia; Unterrainer, Marcus; Gildehaus, Franz J; Rominger, Axel; Bartenstein, Peter; Kälin, Roland E; Glass, Rainer; Albert, Nathalie L

2016-01-01

Noninvasive tumor growth monitoring is of particular interest for the evaluation of experimental glioma therapies. This study investigates the potential of positron emission tomography (PET) using O-(2-(18)F-fluoroethyl)-L-tyrosine ([(18)F]-FET) to determine tumor growth in a murine glioblastoma (GBM) model-including estimation of the biological tumor volume (BTV), which has hitherto not been investigated in the pre-clinical context. Fifteen GBM-bearing mice (GL261) and six control mice (shams) were investigated during 5 weeks by PET followed by autoradiographic and histological assessments. [(18)F]-FET PET was quantitated by calculation of maximum and mean standardized uptake values within a universal volume-of-interest (VOI) corrected for healthy background (SUVmax/BG, SUVmean/BG). A partial volume effect correction (PVEC) was applied in comparison to ex vivo autoradiography. BTVs obtained by predefined thresholds for VOI definition (SUV/BG: ≥1.4; ≥1.6; ≥1.8; ≥2.0) were compared to the histologically assessed tumor volume (n = 8). Finally, individual "optimal" thresholds for BTV definition best reflecting the histology were determined. In GBM mice SUVmax/BG and SUVmean/BG clearly increased with time, however at high inter-animal variability. No relevant [(18)F]-FET uptake was observed in shams. PVEC recovered signal loss of SUVmean/BG assessment in relation to autoradiography. BTV as estimated by predefined thresholds strongly differed from the histology volume. Strikingly, the individual "optimal" thresholds for BTV assessment correlated highly with SUVmax/BG (ρ = 0.97, p GBM mouse model. PVEC is beneficial to improve accuracy of [(18)F]-FET PET SUV quantification. Although SUVmax/BG and SUVmean/BG increase during the disease course, these parameters do not correlate with the respective tumor size. For the first time, we propose a histology-verified method allowing appropriate individual BTV estimation for volumetric in vivo monitoring of tumor growth

[Establishment of EL4 tumor-bearing mouse models and investigation on immunological mechanisms of anti-tumor effect of melphalan].

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Li, Mo-lin; Li, Chuan-gang; Shu, Xiao-hong; Jia, Yu-jie; Qin, Zhi-hai

2006-03-01

To establish mouse lymphoma EL4 tumor-bearing mouse models in wild type C57BL/6 mice and nude C57BL/6 mice respectively, and to further investigate the immunological mechanisms of anti-tumor effect of melphalan. Mouse lymphoma EL4 cells were inoculated subcutaneously into wild type C57BL/6 mice (immune-competent mice). Twelve days later, melphalan of different doses were administered intraperitoneally to treat these wild type C57BL/6 tuomr-bearing mice. Tumor sizes were observed and recorded subsequently to find out the minimal dose of melphalan that could cure the tuomr-bearing mice. Then the same amount of EL4 tumor cells were inoculated subcutaneously into wild type C57BL/6 mice and nude C57BL/6 mice (T cell-deficient mice) simultaneously, which had the same genetic background of C57BL/6. Twelve days later, melphalan of the minimal dose was given intraperitoneally to treat both the wild type and nude C57BL/6 tuomr-bearing mice. Tumor sizes were observed and recorded in these two different types of mice subsequently. A single dose of melphalan (7.5 mg/kg) could cure EL4 tumor-bearing wild type C57BL/6 mice, but could not induce tumor regression in EL4 tumor-bearing nude C57BL/6 mice. A single dose of melphalan has obvious anti-tumor effect on mouse lymphoma EL4 tumor-bearing wild type C57BL/6mice, which requires the involvement of T lymphocytes in the host probably related to their killing functions.

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

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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.

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.

A Time-Delayed Mathematical Model for Tumor Growth with the Effect of a Periodic Therapy.

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Xu, Shihe; Wei, Xiangqing; Zhang, Fangwei

2016-01-01

A time-delayed mathematical model for tumor growth with the effect of periodic therapy is studied. The establishment of the model is based on the reaction-diffusion dynamics and mass conservation law and is considered with a time delay in cell proliferation process. Sufficient conditions for the global stability of tumor free equilibrium are given. We also prove that if external concentration of nutrients is large the tumor will not disappear and the conditions under which there exist periodic solutions to the model are also determined. Results are illustrated by computer simulations.

A Time-Delayed Mathematical Model for Tumor Growth with the Effect of a Periodic Therapy

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Shihe Xu

2016-01-01

Full Text Available A time-delayed mathematical model for tumor growth with the effect of periodic therapy is studied. The establishment of the model is based on the reaction-diffusion dynamics and mass conservation law and is considered with a time delay in cell proliferation process. Sufficient conditions for the global stability of tumor free equilibrium are given. We also prove that if external concentration of nutrients is large the tumor will not disappear and the conditions under which there exist periodic solutions to the model are also determined. Results are illustrated by computer simulations.

The effect of perioperative analgesic drugs omnopon and dexketoprofen on the functional activity of immune cells in murine model of tumor surgery

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R. I. Sydor

2016-08-01

Full Text Available We aimed to investigate the effect of perioperative analgesia with nonselective cyclooxygenase-2 inhibitor dexketoprofen and opioid drug omnopon on the functional activity of immune cells in tumor excision murine model. Lewis lung carcinoma cells were transplanted into hind paw of C57/black mice. On the 23th day tumor was removed. Analgesic drugs were injected 30 min before and once a day for 3 days after the surgery. Biological material was obtained a day before, 1 day and 3 days after the tumor removal. IFN-γ, IL-4, IL-10 and TGF-β mRNA levels in splenic cells were assessed by quantitative real-time RT-PCR. Cytotoxic activity of splenocytes was estimated by flow cytometry. We found that in splenocytes of mice received opioid analgesia IL-10 mRNA level was increased 2.3 times on day one after the surgery compared to preoperative level (P < 0.05, while in dexketoprofen group this parameter did not change. IFN-γ gene expression level on day 3 after tumor removal was 40% higher in splenocytes of dexketoprofen treated mice as compared with omnopon treated animals (P < 0.05. Cytotoxic activity of splenocytes on day 3 postsurgery was (62.2 ± 2.4% in dexketoprofen against (50.2 ± 3.3% in omnopon group. In conclusion, perioperative analgesia with cyclooxygenase inhibitor dexketoprofen in contrast to opioid analgesia with omnopon preserves higher functional activity of murine immune cells in the experimental model of tumor surgery.

Experimental study of 99Tcm-tri-peptide as a novel tumor imaging agent

International Nuclear Information System (INIS)

Xie Wenhui; Cai Xiaojia; Liu Ciyi; Zeng Jun; Zhang Lihua; Lei Bei; Huang Gang

2011-01-01

Objective: To evaluate 99 Tc m -Arg-Glu-Ser ( 99 Tc m -RES) as a potential tumor imaging agent. Methods: RES was synthesized using solid phase peptide synthesis. The optimal labeling conditions of RES were determined under different reagents and reacting temperatures using SnC1 2 as reducing agent.The biodistribution of 99 Tc m -RES was studied in nude mice bearing human lung cancer A549. Results: The radiochemical purity of 99 Tc m -RES was up to 85% and the radiochemical purity was 75% ever after 6 h at room temperature. The tumor uptake of 99 Tc m -RES was obvious and the radioactivity ratios of tumor/blood, tumor/heart, tumor/liver, tumor/lung, tumor/spleen and tumor/muscle were 5.31, 1.88, 1.57, 3.58, 4.16 and 5.92, respectively at 6 h after 99 Tc m -RES injection. Gamma camera imaging showed that tumor uptake of 99 Tc m -RES was negative in rabbits with inflammatory mass but positive in those bearing tumor. The radioactivity ratio of tumor/inflammation was 3.12 at 6 h after injection. Conclusion: 99 Tc m -RES might possibly become a potential tumor imaging agent. (authors)

Effect of fractionated radiotherapy using a hypoxic cell radiosensitizer, RK-28, on experimental murine tumor

International Nuclear Information System (INIS)

Tanaka, Shukaku

1990-01-01

The effect of a hypoxic cell radiosensitizer RK-28, on fractionated radiotherapy was studied using mice with implanted tumors. Experimental animal tumors were third generation isoplants of a mammary carcinoma which arose spontaneously in a C 3 H/He mouse. RK-28 was given to the mice at two dosages: 0.4 mg/g,b.wt. and 0.2 mg/g.b.wt. Total dose of irradiation was 20 Gy which was divided into the first 10 Gy irradiation and the second 10 Gy performed after a proper time interval such as 1, 24, 48 and 72 hours after the first 10 Gy irradiation. Tumor growth was evaluated by TGT 50 /3 times, which was defined as the time required for 50% of the tumors to regrow to the 3 times value of its initial volume. Tumor volume was measured every day and TGT 50 /3 times was calculated by logit analysis method. No significant differences were found in the TGT 50 /3 times among the groups treated by radiation alone, those treated by RK-administration alone and those without any treatment. TGT 50 value of control group without any treatment was 3.40 (days). TGT 50 value of another group treated by RK-28 alone was 3.46. and TGT 50 value of 20 Gy X-ray irradiation alone was 10.23. Under the fractionated X-ray irradiation alone, TGT 50 values of the various time interval such as 9, 14, 48 and 72 hours were 11.26, 10.42, 12.14 and 1.10. Under the combined treatment of the fractionated X-ray irradiation and RK-28 administration, TGT 50 values were 17.84, 16.42, 16.59 and 17.49. These TGT 50 /3 times values showed that RK-28 had a radiosensitizing effect when given with fractionated radiotherapy even at lower doses of RK-28 administration and radiation. Therefore, it was suggested that fractionated radiotherapy using RK-28 was useful in the cancer treatment. (author) 52 refs

Injury Based on Its Study in Experimental Models

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M. Mendes-Braz

2012-01-01

Full Text Available The present review focuses on the numerous experimental models used to study the complexity of hepatic ischemia/reperfusion (I/R injury. Although experimental models of hepatic I/R injury represent a compromise between the clinical reality and experimental simplification, the clinical transfer of experimental results is problematic because of anatomical and physiological differences and the inevitable simplification of experimental work. In this review, the strengths and limitations of the various models of hepatic I/R are discussed. Several strategies to protect the liver from I/R injury have been developed in animal models and, some of these, might find their way into clinical practice. We also attempt to highlight the fact that the mechanisms responsible for hepatic I/R injury depend on the experimental model used, and therefore the therapeutic strategies also differ according to the model used. Thus, the choice of model must therefore be adapted to the clinical question being answered.

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

. 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...

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

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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

Predicting oropharyngeal tumor volume throughout the course of radiation therapy from pretreatment computed tomography data using general linear models.

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Yock, Adam D; Rao, Arvind; Dong, Lei; Beadle, Beth M; Garden, Adam S; Kudchadker, Rajat J; Court, Laurence E

2014-05-01

The purpose of this work was to develop and evaluate the accuracy of several predictive models of variation in tumor volume throughout the course of radiation therapy. Nineteen patients with oropharyngeal cancers were imaged daily with CT-on-rails for image-guided alignment per an institutional protocol. The daily volumes of 35 tumors in these 19 patients were determined and used to generate (1) a linear model in which tumor volume changed at a constant rate, (2) a general linear model that utilized the power fit relationship between the daily and initial tumor volumes, and (3) a functional general linear model that identified and exploited the primary modes of variation between time series describing the changing tumor volumes. Primary and nodal tumor volumes were examined separately. The accuracy of these models in predicting daily tumor volumes were compared with those of static and linear reference models using leave-one-out cross-validation. In predicting the daily volume of primary tumors, the general linear model and the functional general linear model were more accurate than the static reference model by 9.9% (range: -11.6%-23.8%) and 14.6% (range: -7.3%-27.5%), respectively, and were more accurate than the linear reference model by 14.2% (range: -6.8%-40.3%) and 13.1% (range: -1.5%-52.5%), respectively. In predicting the daily volume of nodal tumors, only the 14.4% (range: -11.1%-20.5%) improvement in accuracy of the functional general linear model compared to the static reference model was statistically significant. A general linear model and a functional general linear model trained on data from a small population of patients can predict the primary tumor volume throughout the course of radiation therapy with greater accuracy than standard reference models. These more accurate models may increase the prognostic value of information about the tumor garnered from pretreatment computed tomography images and facilitate improved treatment management.

Predicting oropharyngeal tumor volume throughout the course of radiation therapy from pretreatment computed tomography data using general linear models

International Nuclear Information System (INIS)

Yock, Adam D.; Kudchadker, Rajat J.; Rao, Arvind; Dong, Lei; Beadle, Beth M.; Garden, Adam S.; Court, Laurence E.

2014-01-01

Purpose: The purpose of this work was to develop and evaluate the accuracy of several predictive models of variation in tumor volume throughout the course of radiation therapy. Methods: Nineteen patients with oropharyngeal cancers were imaged daily with CT-on-rails for image-guided alignment per an institutional protocol. The daily volumes of 35 tumors in these 19 patients were determined and used to generate (1) a linear model in which tumor volume changed at a constant rate, (2) a general linear model that utilized the power fit relationship between the daily and initial tumor volumes, and (3) a functional general linear model that identified and exploited the primary modes of variation between time series describing the changing tumor volumes. Primary and nodal tumor volumes were examined separately. The accuracy of these models in predicting daily tumor volumes were compared with those of static and linear reference models using leave-one-out cross-validation. Results: In predicting the daily volume of primary tumors, the general linear model and the functional general linear model were more accurate than the static reference model by 9.9% (range: −11.6%–23.8%) and 14.6% (range: −7.3%–27.5%), respectively, and were more accurate than the linear reference model by 14.2% (range: −6.8%–40.3%) and 13.1% (range: −1.5%–52.5%), respectively. In predicting the daily volume of nodal tumors, only the 14.4% (range: −11.1%–20.5%) improvement in accuracy of the functional general linear model compared to the static reference model was statistically significant. Conclusions: A general linear model and a functional general linear model trained on data from a small population of patients can predict the primary tumor volume throughout the course of radiation therapy with greater accuracy than standard reference models. These more accurate models may increase the prognostic value of information about the tumor garnered from pretreatment computed tomography

Constructing TC-1-GLUC-LMP2 Model Tumor Cells to Evaluate the Anti-Tumor Effects of LMP2-Related Vaccines

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Sun, Liying; Hao, Yanzhe; Wang, Zhan; Zeng, Yi

2018-01-01

Epstein-Barr virus (EBV) is related to a variety of malignant tumors, and its encoded protein, latent membrane protein 2 (LMP2), is an effective target antigen that is widely used to construct vector vaccines. However, the model cells carrying LMP2 have still not been established to assess the oncolytic effect of LMP2-related vaccines at present. In this study, TC-1-GLUC-LMP2 tumor cells were constructed as target cells to evaluate the anti-tumor effects of LMP2-assosiated vaccines. The results showed that both LMP2 and Gaussia luciferase (GLuc) genes could be detected by polymerase chain reaction (PCR) and reverse transcription-polymerase chain reaction (RT-PCR) in TC-1-GLUC-LMP2 cells. Western blot results showed that the LMP2 and Gaussia luciferase proteins were stably expressed in tumor cells for at least 30 generations. We mixed 5 × 104 LMP2-specific mouse splenic lymphocytes with 5 × 103 TC-1-GLUC-LMP2 target cells and found that the target cells were killed as the specific killing effect was obviously enhanced by the increased quantities of LMP2-peptide stimulated spleens. Furthermore, the tumor cells could not be observed in the mice inoculated TC-1-GLUC-LMP2 cells after being immunized with vaccine-LMP2, while the vaccine-NULL immunized mice showed that tumor volume gradually grew with increased inoculation time. These results indicated that the TC-1-GLUC-LMP2 cells stably expressing LMP2 and GLuc produced tumors in mice, and that the LMP2-specific cytotoxic T lymphocyte (CTL) effectively killed the cells in vitro and in vivo, suggesting that TC-1-GLUC-LMP2 cells can be used as model cells to assess the immune and antitumor effects of LMP2-related vaccines. PMID:29570629

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

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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.

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

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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.

Experimental study on anti-tumor effect of pcEgr-IFNγ gene-radiotherapy

International Nuclear Information System (INIS)

Wu Congmei; Li Xiuyi; Liu Shuzheng

2001-01-01

Objective: To study the anti-tumor effect of IFN γ gene-radiotherapy to murine melanoma and its immunologic mechanism. Methods: pcEgr-IFNγ plasmids were injected locally into tumor, and 36 hours later, the tumors were given 20 Gy X-ray irradiation. Tumor growth at different time, IFN γ expression 3 days later and immunologic indexes 15 days later were detected. Results: At 3-15 days after pcEgr-IFNγ gene-radiotherapy, the tumor growth rate was lower than that of irradiation alone group. It was also lower than that of gene therapy alone group and control plasmid combined with X-ray irradiation group significantly. Day 3 tumor IFN γ expression was higher than that of plasmid treatment alone group. NK activity, IL-2 and IFN γ secretion activities were higher than those of gene therapy alone and irradiation alone groups significantly. Conclusion: The antitumor effect of IFN γ gene-radiotherapy is better than that of either of them applied solely. Its mechanism might be concerned with the higher expression of IFN γ induced by irradiation in tumors and activation of anti-tumor immunologic functions

Modeling of Experimental Adsorption Isotherm Data

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Xunjun Chen

2015-01-01

Full Text Available Adsorption is considered to be one of the most effective technologies widely used in global environmental protection areas. Modeling of experimental adsorption isotherm data is an essential way for predicting the mechanisms of adsorption, which will lead to an improvement in the area of adsorption science. In this paper, we employed three isotherm models, namely: Langmuir, Freundlich, and Dubinin-Radushkevich to correlate four sets of experimental adsorption isotherm data, which were obtained by batch tests in lab. The linearized and non-linearized isotherm models were compared and discussed. In order to determine the best fit isotherm model, the correlation coefficient (r2 and standard errors (S.E. for each parameter were used to evaluate the data. The modeling results showed that non-linear Langmuir model could fit the data better than others, with relatively higher r2 values and smaller S.E. The linear Langmuir model had the highest value of r2, however, the maximum adsorption capacities estimated from linear Langmuir model were deviated from the experimental data.

Modeling protective anti-tumor immunity via preventative cancer vaccines using a hybrid agent-based and delay differential equation approach.

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Kim, Peter S; Lee, Peter P

2012-01-01

A next generation approach to cancer envisions developing preventative vaccinations to stimulate a person's immune cells, particularly cytotoxic T lymphocytes (CTLs), to eliminate incipient tumors before clinical detection. The purpose of our study is to quantitatively assess whether such an approach would be feasible, and if so, how many anti-cancer CTLs would have to be primed against tumor antigen to provide significant protection. To understand the relevant dynamics, we develop a two-compartment model of tumor-immune interactions at the tumor site and the draining lymph node. We model interactions at the tumor site using an agent-based model (ABM) and dynamics in the lymph node using a system of delay differential equations (DDEs). We combine the models into a hybrid ABM-DDE system and investigate dynamics over a wide range of parameters, including cell proliferation rates, tumor antigenicity, CTL recruitment times, and initial memory CTL populations. Our results indicate that an anti-cancer memory CTL pool of 3% or less can successfully eradicate a tumor population over a wide range of model parameters, implying that a vaccination approach is feasible. In addition, sensitivity analysis of our model reveals conditions that will result in rapid tumor destruction, oscillation, and polynomial rather than exponential decline in the tumor population due to tumor geometry.

Comparative value of clinical, cytological, and histopathological features in feline mammary gland tumors; an experimental model for the study of human breast cancer.

Science.gov (United States)

Shafiee, Radmehr; Javanbakht, Javad; Atyabi, Nahid; Bahrami, Alimohammad; Kheradmand, Danial; Safaei, Reyhaneh; Khadivar, Farshid; Hosseini, Ehsan

2013-08-13

The diagnosis of breast lesions is usually confirmed by fine-needle aspiration cytology (FNAC) or histological biopsy. Although there is increasing literature regarding the advantages and limitations of both modalities, there is no literature regarding the accuracy of these modalities for diagnosing breast lesions in high-risk patients, who usually have lesions detected by screening. Moreover, few studies have been published regarding the cytopathology of mammary tumors in cats despite widespread use of the animal model for breast cancer formation and inhibition. The objective of the present study was to evaluate the diagnostic interest of cytological and histopathological analysis in feline mammary tumours (FMTs), in order to evaluate its possible value as an animal model. The study was performed in 3 female cats submitted to surgical resections of mammary tumours. The mammary tumours were excised by simple mastectomy or regional mastectomy, with or without the superficial inguinal lymph nodes. Female cats were of different breeds (1 siamese and 2 persians). Before surgical excision of the tumour, FNA cytology was performed using a 0.4 mm diameter needle attached to a 8 ml syringe held in a standard metal syringe holder. The cytological sample was smeared onto a glass slide and either air-dried for May-Grünwald-stain and masses were surgically removed, the tumours were grossly examined and tissue samples were fixed in 10%-buffered-formalin and embedded in paraffin. Sections 4 μm thick were obtained from each sample and H&E stained. Cytologically, atypical epithelial cells coupled to giant nucleus, chromatin anomalies, mitotic figures, spindle shape cells, anisocytosis with anisokaryosis and hyperchromasia were found. Histologically, these tumors are characterized by pleomorphic and polygonal cell population together with mitotic figures, necrotic foci and various numbers inflammatory foci. Also, spindle shaped cells, haemorrhage localized in the different

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

A multiplexed microfluidic system for evaluation of dynamics of immune-tumor interactions.

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Moore, N; Doty, D; Zielstorff, M; Kariv, I; Moy, L Y; Gimbel, A; Chevillet, J R; Lowry, N; Santos, J; Mott, V; Kratchman, L; Lau, T; Addona, G; Chen, H; Borenstein, J T

2018-05-25

Recapitulation of the tumor microenvironment is critical for probing mechanisms involved in cancer, and for evaluating the tumor-killing potential of chemotherapeutic agents, targeted therapies and immunotherapies. Microfluidic devices have emerged as valuable tools for both mechanistic studies and for preclinical evaluation of therapeutic agents, due to their ability to precisely control drug concentrations and gradients of oxygen and other species in a scalable and potentially high throughput manner. Most existing in vitro microfluidic cancer models are comprised of cultured cancer cells embedded in a physiologically relevant matrix, collocated with vascular-like structures. However, the recent emergence of immune checkpoint inhibitors (ICI) as a powerful therapeutic modality against many cancers has created a need for preclinical in vitro models that accommodate interactions between tumors and immune cells, particularly for assessment of unprocessed tumor fragments harvested directly from patient biopsies. Here we report on a microfluidic model, termed EVIDENT (ex vivo immuno-oncology dynamic environment for tumor biopsies), that accommodates up to 12 separate tumor biopsy fragments interacting with flowing tumor-infiltrating lymphocytes (TILs) in a dynamic microenvironment. Flow control is achieved with a single pump in a simple and scalable configuration, and the entire system is constructed using low-sorption materials, addressing two principal concerns with existing microfluidic cancer models. The system sustains tumor fragments for multiple days, and permits real-time, high-resolution imaging of the interaction between autologous TILs and tumor fragments, enabling mapping of TIL-mediated tumor killing and testing of various ICI treatments versus tumor response. Custom image analytic algorithms based on machine learning reported here provide automated and quantitative assessment of experimental results. Initial studies indicate that the system is capable of

A novel pre-clinical in vivo mouse model for malignant brain tumor growth and invasion.

Science.gov (United States)

Shelton, Laura M; Mukherjee, Purna; Huysentruyt, Leanne C; Urits, Ivan; Rosenberg, Joshua A; Seyfried, Thomas N

2010-09-01

Glioblastoma multiforme (GBM) is a rapidly progressive disease of morbidity and mortality and is the most common form of primary brain cancer in adults. Lack of appropriate in vivo models has been a major roadblock to developing effective therapies for GBM. A new highly invasive in vivo GBM model is described that was derived from a spontaneous brain tumor (VM-M3) in the VM mouse strain. Highly invasive tumor cells could be identified histologically on the hemisphere contralateral to the hemisphere implanted with tumor cells or tissue. Tumor cells were highly expressive for the chemokine receptor CXCR4 and the proliferation marker Ki-67 and could be identified invading through the pia mater, the vascular system, the ventricular system, around neurons, and over white matter tracts including the corpus callosum. In addition, the brain tumor cells were labeled with the firefly luciferase gene, allowing for non-invasive detection and quantitation through bioluminescent imaging. The VM-M3 tumor has a short incubation time with mortality occurring in 100% of the animals within approximately 15 days. The VM-M3 brain tumor model therefore can be used in a pre-clinical setting for the rapid evaluation of novel anti-invasive therapies.

Genetic ablation of soluble tumor necrosis factor with preservation of membrane tumor necrosis factor is associated with neuroprotection after focal cerebral ischemia

DEFF Research Database (Denmark)

Madsen, Pernille M; Clausen, Bettina H; Degn, Matilda

2016-01-01

Microglia respond to focal cerebral ischemia by increasing their production of the neuromodulatory cytokine tumor necrosis factor, which exists both as membrane-anchored tumor necrosis factor and as cleaved soluble tumor necrosis factor forms. We previously demonstrated that tumor necrosis factor...... reduced infarct volumes at one and five days after stroke. This was associated with improved functional outcome after experimental stroke. No changes were found in the mRNA levels of tumor necrosis factor and tumor necrosis factor-related genes (TNFR1, TNFR2, TACE), pro-inflammatory cytokines (IL-1β, IL-6...... knockout mice display increased lesion volume after focal cerebral ischemia, suggesting that tumor necrosis factor is neuroprotective in experimental stroke. Here, we extend our studies to show that mice with intact membrane-anchored tumor necrosis factor, but no soluble tumor necrosis factor, display...

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.

3D bioprinting: improving in vitro models of metastasis with heterogeneous tumor microenvironments.

Science.gov (United States)

Albritton, Jacob L; Miller, Jordan S

2017-01-01

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. © 2017. Published by The Company of Biologists Ltd.