bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 4182: A screen for genes that define the strong gender bias nature of hepatocellular carcinoma using a transposon mutagenesis murine model
Authors: Keng Vincent W. , Ryan Barbara J. , Silverstein Kevin A.T. , Sarver Aaron , Fan Danhua , Dupuy Adam J. , Jenkins Nancy A. , Copeland Neal G. , Largaespada David A.
Published: February 2011

Introduction: Hepatocellular carcinoma (HCC) is a deadly disease where many of the underlying associated genetic mechanisms remain undiscovered. Although HCC has been relatively rare in the US, the growing number of patients with cirrhosis (due to hepatitis infection and/or obesity-related fatty liver) has accounted for a surge in the incidence of HCC. Using the conditional Sleeping Beauty (SB) transposon somatic insertional mutagenesis system in transgenic mice, a novel unbiased HCC genetic screen was performed to elucidate the important genes responsible for this disease1.

Methods: Triple transgenic (containing the conditional SB transposase, transposon mutagenic vector and liver-specific Cre transgenes) and quadruple transgenic (as above plus a conditional dominant negative p53 allele) mice were generated and aged for tumorigenesis1.

Results: Using this system combined with a conditional p53-deficient background, we were able to identify many HCC cancer candidate genes. In addition, liver tumor nodules were also isolated from experimental mice without a predisposed genetic background. Liver tumors were prevalent in male experimental mice, mimicking the strong gender bias in the incidence of HCC seen in humans. Liver tumors were isolated from female experimental mice with and without a p53-deficient background, only after a prolonged latency (>432-days). From wild-type female liver tumors, we identified 17 candidate genes including the Pten tumor suppressor gene. From p53-deficient female liver tumors, we identified 6 candidate genes including some genes that are implicated in the miRNA18a pathway. This miRNA pathway has been associated with increased incidence of HCC in female patients.

Conclusion: SB system allows for the identification of putative genes involved in HCC development in female mice. Finally, our ultimate goal is that candidate genes will be useful in generating possible therapeutic agents for the treatment of HCC and increase our knowledge in defining the underlying genetic mechanisms associated with the strong gender bias nature of this deadly disease.

1. Keng, V.W., et al. (2009). A conditional transposon-based insertional mutagenesis screen for genes associated with mouse hepatocellular carcinoma. Nat Biotechnol. 27, 264-74.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4182.
Abstract 4184: Development of ixabepilone-induced CIPN is related to pre-treatment with paclitaxel in a mouse model
Authors: Carlson Karen-Sue B. , Ramnarain Anita , Strickland Sidney , Vahdat Linda T.
Published: February 2011

The mechanisms and underlying factors that predispose individuals to development of chemotherapy-induced peripheral neuropathy (CIPN) are not clearly understood. CIPN results in the dose attenuation, delay, or discontinuation of drug in patients otherwise responding to chemotherapy. Moderate to severe CIPN can interfere with function and activities of daily living. Microtubule-stabilizing agents, including taxanes and epothilones are strongly associated with development of CIPN. Ixabepilone, the first FDA-approved epothilone, is specifically used in taxane-resistant metastatic breast cancer. Any ixabepilone-induced CIPN may be as high as 71% depending on administration regimen. Specific risk factors for development of this side effect are unknown.

Here we present data using a murine model of sensory hyperalgesia that suggests pretreatment with paclitaxel, currently a labeling indication for use of ixabepilone in metastatic breast cancer, is itself a predisposing factor for development of ixabepilone-induced peripheral neuropathy. Wild type DB/A2 adult mice were treated with intraperitoneal 25 mg/kg paclitaxel, 2.5 mg/kg ixabepilone, or diluent (cremophor: ethanol) every other day for 4 doses. Mice were analyzed by rota-rod to test sensory-motor function and by hot and cold plate to test for temperature hyperalgesia. There was no difference in performance of either of the three treatment groups following the initial treatment cycle. Mice were then treated with a further cycle of chemotherapy, either the same as they received initially, except that half of the paclitaxel-treated group was crossed-over to ixabepilone. Rota-rod and hot plate testing again failed to show a difference between groups. However, cold-plate testing showed a statistically significant increase in cold hyperalgesia in mice treated first with paclitaxel followed by ixabepilone in comparison to all other treatment groups. EM and immunofluorescence analyses of dorsal root ganglia and sciatic nerve sections from mice in all four treatment groups are ongoing.

Although preliminary, these results suggest that prior chemotherapy regimens have a significant effect on development of CIPN in this model. The exact mechanisms of injury are under evaluation. A complementary clinical study is underway in women with breast cancer to understand the effect of ixabepilone on an ultrastructural level and its potential role in the development of peripheral neuropathy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4184.
Abstract 4185: Isolation of cancer stem-like cells from a novel orthotopic xenograt model of supratentorial primitive neuroectodermal tumor that is susceptible to oncolytic Seneca Valley Virus
Authors: Liu Zhigang , Zhao Xiumei , Adesina Adenkunle M. , Baxter Patricia , Zhao Yijue , Rao Pulavalti , Su Jack M. , Perlaky Lazlo , Dauser Robert , Chintagumpala Murali , Lau Ching C. , Blaney Susan M. , Li Xiao-Nan
Published: February 2011

Purpose: Supratentorial primitive neuroectodermal tumor (PNET) accounts for 2-3% of all pediatric brain tumors. Despite multimodality therapies, the clinical outcome remains poor, and the 5-year progression free survival rate is less than 40%. Clinically relevant animal models are needed for understanding tumor biology and developing more effective therapies. Here we report our recent development of a clinically relevant animal model, isolation and characterization of cancer stem-like cells in the xenograft tumors, and preclinical investigation of the antitumor efficacy of a novel picorna oncolytic virus Seneca Valley Virus-001 (SVV-001) both in vitro and vivo, especially in cancer stem-like cells.

Experimental Design: Orthotopic xenograft mouse model was developed by direct injection of 105 tumor cells from a freshly resected brain PNET tumor specimen into the right cerebrum of Rag2/severe combined immunodeficient mice. CD133+ cells were quantitatively analyzed and isolated with FACS using human-specific antibodies against CD133. Antitumor activity of SVV-001was evaluated in vitro in cultured xenograft tumor cells and in vivo in mice bearing pre-formed xenograft tumors.

Results: A novel transplantable PNET xenograft model IC-2664PNT was established. The xenograft tumors not only replicate the biologic phenotypes but also preserve cancer stem-like cell pools. The IC-2664PNET neurospheres, which expressed high levels of CD133 and nestin, were efficiently infected and killed by SVV-001 (0.5-25 virus particle/ cell). A single tail vein injection of SVV-001 (5×1012 virus particle/kg) prolonged survival time of PNET xenograft model.

Conclusions: We have established the first clinically relevant animal model for childhood supratentorial PNET. It replicated the major histopathological features of the original patient tumor, and preserved a CD133+ stem cells pool during serial subtransplantations. SVV-001 has potent antitumor efficacy in PNET, especially selectively kill cancer stem-like cells, and prolong survival in vivo.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4185.
Abstract 4187: A rapid and robust transgenic high-grade glioma mouse model for therapy-intervention studies
Authors: de Vries Nienke A. , Bruggeman Sophia W. , de Vries Hilda I. , Zevenhoven John , Buckle Tessa , Hamans Bob C. , Leenders William P. , Beijnen Jos H. , van Lohuizen Maarten , Berns Anton J.M. , van Tellingen Olaf
Published: February 2011

High-grade glioma is a devastating and uniformly fatal disease for which better therapy is urgently needed. Glioma cells extensively infiltrate into surrounding pivotal brain structures, thereby rendering current treatments largely ineffective. Evaluation of novel therapies requires the availability of appropriate glioma mouse models. We here present a novel transgenic mouse model of high-grade glioma that can be conveniently used for testing therapy-intervention strategies.

High-grade gliomas were induced by stereotactic intracranial injection of self-deleting lentiviral GFAP-Cre or CMV-Cre vectors into adult immune-competent compound LoxP-conditional mice, resulting in localized expression of K-Rasv12 in conjunction with loss of p16Ink4a/p19Arf with or without concomitant loss of p53 or Pten. Tumors have been characterized by histology, immune-histochemistry and magnetic resonance imaging and reproduced many of the features that are characteristic for human high-grade gliomas, including invasiveness and blood-brain barrier functionality. We are currently assessing which molecular alterations in cell signaling pathways have occurred.

Especially CMV-Cre injection into p53;Ink4a/Arf;K-Rasv12 mice resulted in grade IV (glioblastoma multiforme) with a short tumor latency (2-3 weeks) and full penetrance. Early detection and follow-up of tumor growth can be accomplished conveniently by non-invasive bioluminescence imaging and the practical utility for therapy-intervention has been demonstrated in a study with temozolomide. Temozolomide delayed tumor progression modestly but significantly in line with what is observed in patients. Importantly, this novel model can be used with almost the same convenience as traditional xenograft models, thus allowing the implementation of realistic high grade glioma models at the forefront of preclinical evaluation. We expect that this model will be particularly useful to assess the potential clinical utility of agents that may augment temozolomide cytotoxicity, such as PARP-inhibitors or Wee1 kinase inhibitors, but also for agents targeting activated RAS and/or PI3K-Akt-mTor signaling pathways.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4187.
Abstract 4188: Protein profiling of the first genetically engineered murine model of brainstem glioma
Authors: Nazarian Javad , Becher Oren J. , Hathout Yetrib , MacDonald Tobey J.
Published: February 2011

Brainstem gliomas account for about 15% of all pediatric brain tumors and are the leading cause of death for pediatric brain cancers. The PDGFB induced mouse model of brainstem glioma (BSG) uses the RCAS/t-va system and is the first genetically engineered murine model of the disease. Tumors of these mice exhibit histopathological characteristics of pediatrics BSGs. Tumorigenesis is driven by overexpression of PDGFB in nestin expressing progenitors and accelerated by deletion of INK4A-ARF. Although PDGFB is known to be highly expressed both in these mice and a subset of pediatric BSGs, the exact mechanisms of disease formation and progression is not well understood.

In an attempt to explore the molecular mechanisms of PDGFB-mediated tumor formation, we generated the complete protein profiles of brainstem samples obtained from normal (n=3) and PDGFB-induced BSG (N=3) mice. Total proteins were extracted, tryspin digested and resulting peptides were analyzed by shotgun proteomics (LC-MS/MS) and proteins were identified using Sequest algorithm. Label-free analysis was performed using ProteoIQ software.

A total of 1,363 proteins were confidently identified by using the following stringent filtration criteria: > 2 peptides/protein, >10 spectra/protein, minimum peptide probability of 0.95, and a minimum peptide length of 5 amino acids. Our analysis identified overlap in several molecular pathways that we had previously reported in proteomic profiling of pediatric formalin fixed autopsy specimens. Some of the proteins that showed similar dysregulation included: ALDOC, EEF1A1, GPI, PKM2, and SPTBN1. Furthermore, the list of proteins and their expression values were analyzed by the Ingenuity Pathway Assist (IPA). IPA derives molecular interactions based on published data and peer-reviewed manuscripts. Our analysis showed that 228 of these proteins have been reported to play a role brain tumor or other types of cancer. Together, our protein analysis of the first murine model of BSG has provided significant additional insights regarding into PDGFB-induced oncogenesis and molecular perturbations.

Our analysis is the first report of the comprehensive protein profile of this novel BSG murine model. Pathways and molecular interactions identified by this combined comparative proteomic approach will require further validation both using additional samples obtained from the murine BSG model as well as human postmortem BSG specimens. Such validations may lead to the identification of therapeutic targets and improve our understanding of the biology of BSG.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4188.
Abstract 4191: Thymidylate synthase accelerates development of pituitary tumors in Men1 knockout mice
Authors: Lee Hye Seung , Chen Min , Hwang Jin Hyeok , Sarfaraz Sami , Giaccone Giuseppe , Zajac-Kaye Maria
Published: February 2011

Thymidylate synthase (TS) is a key enzyme for DNA biosynthesis during cellular proliferation. Studies from our laboratory have demonstrated oncogenic activity of TS in mammalian cells (Cancer Cell, 5 p341, 2004) and in transgenic mice that overexpress human TS (hTS) (Oncogene v26 p4814, 2007). To investigate the in vivo role of TS in pituitary tumorigenesis, we crossed hTS transgenic mice with conditional Men1 knockout mice. We found that overexpression of hTS in fMen1−/− mice significantly decreased the age of onset and increased the incidence of pituitary tumors. fMen1−/−hTS mice developed adenoma and carcinoma as early as 6 and 7 month respectively, while the development of these tumor was not observed in fMen1−/− mice until after 8 month of age. By 8 months of age, 12.1% fMen1−/−hTS mice developed adenoma while no adenoma was observed in fMen1−/− mice. At 10 month of age, progression of pituitary adenoma to carcinoma occurred with higher incidence (51.6%) in fMen1−/−hTS as compared to fMen1−/− mice (18.2%) (p=0.013). Using immunohistochemistry and immunoblotting analysis we confirmed expression of ectopic hTS protein in pituitary tumors of fMen1−/−hTS mice. Our results demonstrated that TS enhances the development and progression of pituitary tumors and suggested that this transgenic model can be use to study the in vivo consequences of elevated hTS on DNA stability, to test how this relates to tumorigenesis, and to improve the use of hTS as a biomarker and therapeutic target. The impact of this work is that it would show that elevated hTS is playing an active role in promoting tumor cell proliferation and is not a simply a passive target for chemotherapy agents to induce cellular toxicity.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4191.
Abstract 4196: Successful establishment of human rhabdomyosarcoma xenografts in a human-adapted mouse model
Authors: Seitz Guido , Pfeiffer Matthias , Warmann Steven W. , Handgretinger Rupert , Leuschner Ivo , Fuchs Jörg , Armeanu-Ebinger Sorin
Published: February 2011

Purpose:

The outcome of patients with advanced stage rhabdomyosarcoma is still sobering. Treatment results cannot be improved by conservative treatment options. Therefore, novel treatment approaches such as immunotherapy need to be evaluated in human-adapted animal models. The aim of this study was to develop a humanized mouse model of childhood rhabdomyosarcoma as a basis for studies of immunotherapeutic approaches.

Methods:

NOD/LtSz-scid IL2R gamma null mice were used for all experiments (n =14). Animals underwent subletal irradiation (1 × 300cGy). Afterwards, transplantation of human CD34+-cells (1.000.000 cells per animal i.v.) was carried out. Eight weeks after transplantation, subcutaneous xenotransplantation of human alveolar (Rh30) and embryonal rhabdomyosarcoma (RD) cell lines was carried out. Engraftment of human cells was assessed in peripheral blood at day 21 and at day 55 of the experiment. Animals were sacrified and tumors were resected 93 days after CD34+-transplantation.

Results:

Successful engraftment of human cells with establishment of a human immune system was observed in 12 of 14 animals. B-cells and T-cells were mostly detected in the peripheral blood. There were only a few monocytes and nearly no NK-cells. Xenotransplantation of alveolar RMS resulting in subcutaneous tumor growth was feasible in 7 animals. Xenotransplantation of embryonal RMS was performed in 5 animals and led to tumor growth in 1 animal. Histological work up showed either alveolar or embryonal RMS cells with central necrosis.

Conclusion:

For the first time, we developed a xenotransplantation model of human rhabdomyosarcoma in a humanized mouse model. Establishment of subcutaneous tumor xenografts was more effective in alveolar subtype. This model will serve as basic research tool for further analysis of novel immunotherapeutic approaches in solid pediatric tumors.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4196.
Abstract 4197: Mouse xenograft models of human soft tissue sarcomas
Authors: Sicinska Ewa , Moss Samuel , Brito Joseph , Priolo Carmen , Finn Stephen , Wagner Andrew , Demetri George , Loda Massimo
Published: February 2011

Sarcoma represents a class of tumors arising from mesenchymal tissue. New approaches that target sarcoma-specific molecular alterations hold a promise of more effective therapies. Currently available sarcoma models do not accurately resemble relevant properties of the human disease and very often are inadequate for predicting the efficacy of investigational drugs in preclinical settings. Thus, in order to test novel targeted therapies, it is essential to develop in vivo models of sarcomas.

To this end, we have created a panel of well-characterized xenografts of primary human sarcomas that represent a spectrum of histotypes. Specifically, we transplanted intact human sarcomas under the skin of immunodeficient mice. We then compared the morphologic, phenotypic, and genetic characteristics of the tumor tissues before and after implantation in recipient mice.

To date, we have implanted into Nu/Nu recipients tumor tissue fragments from 32 gastrointestinal stromal tumors (GIST) 10 dedifferentiated liposarcomas and 6 leiomyosarcomas. Successful tumor growth was detected in 86% cases of GIST, 44% of liposarcomas and 33% of leiomyosarcomas. Upon serial transplantation, 35% of GISTs, 44% of liposarcomas and 33% of leiomyosarcomas have grown beyond passage F3. Histological analysis of the primary tumors and corresponding xenografts revealed that morphology and immunophenotype (c-Kit status for GISTs, MDM2 for liposarcomas, Smooth Muscle Actin for leiomyosarcomas) was retained throughout all passages. Moreover, all major genetic abnormalities present in the primary tumors were retained in the xenografts, as revealed by genome-wide Single Nucleotide Polymorphism (SNP) array analyses.

Our results show that this approach can be used to generate animal models that faithfully reproduce characteristics of human intact tumors. These models can be used for in vivo preclinical drug testing, diagnostic and prognostic molecular markers discovery, and for identification of molecular mechanisms of drug resistance.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4197.
Abstract 4198: Characterization of basal cell carcinoma (BCC) allograft in comparison with spontaneous murine BCCs
Authors: Wang Grace Y. , So Po-Lin , Libove Eileen , Epstein Ervin H.
Published: February 2011

Small molecule inhibitors against Hedgehog (HH) activity have become one of the hottest targets in cancer drug development. This is because HH pathway has been found to play a role in possibly as many as 30% of all human malignancies, including basal cell carcinoma (BCC), medulloblastoma, rhabdomyosarcoma, pancreatic, gastrointestinal, ovarian, and prostate cancers, some leukemias, and multiple myeloma. Ptch 1+/− mice develop BCCs after UV or ionizing radiation and provide an excellent model system for investigating the HH regulatory system, studying the effect of HH in cancer biology, and evaluating tumor intervention therapies. However, there are intrinsic limitations to the use of autochthonous mouse tumors to investigate therapeutic interventions, including inter-tumor variability and long tumor latency, necessitating the enrolling of numerous mice to assess the efficacy of any intervention. One approach to circumventing these problems is to use tumor allografts. In the present study we aimed to develop BCC tumor allografts, which have not previously been established successfully, and to compare their histology, growth rate, vasculature, and sensitivity to drug treatment with that of their parental tumors. We injected single cell suspensions derived from primary murine BCCs into multiple NOD/SCID mice and compared allograft histology (H&E) and immunophenotype (Ki67, Gli1 and CD31) with that of the parental tumors. We found that allografts generated from the same spontaneous tumor were relatively similar to one another and reproduced the histology of the parental tumor, exhibiting either an infiltrative subtype or a nested structure resembling infiltrative/trichoepithelioma or nodular human BCC subtypes respectively. Consistent with their faster growth rate, allograft tumors showed greater Ki67 staining than did primary tumors. However, allografts expressed slightly reduced Gli1 levels. Similar vascular distribution was observed in both tumor models. Finally, we tested the tumor allograft sensitivity to HH inhibitor treatments.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4198.
Abstract 4200: Transgenic mice overexpressing a Claudin-6 tail deletion mutant are resistant to tumor formation
Authors: Turksen Kursad , Arabzadeh Azadeh , Troy Tammy-Claire
Published: February 2011

Morphological and physiological observations suggest that the tight junction (TJ)-based permeability barrier is modified/disrupted during tumorigenesis. It is now also widely recognized that the Claudin (Cldn) family of four tetraspan transmembrane proteins is crucial for tight junction assembly and permeability barrier function. However, the detailed roles of the Cldn cytoplasmic tail and extracellular loop domains in these processes or their dysfunction in tumorigenesis are not yet understood. We recently demonstrated that the tail domain of Cldn6 is crucial for membrane targeting and epidermal permeability barrier (EPB) formation, by forced expression of a Cldn6 tail deletion mutant (CDelta187) via the involucrin (Inv) promoter in the suprabasal compartment of the mouse epidermis. Even though a functional barrier formed, Inv-CDelta187 mice displayed histological and biochemical abnormalities in the epidermal differentiation program leading to a thickening of the epidermis after 1 week of age that persisted throughout life. Notably, a significant amount of not only Cldn6, but also Cldn10, Cldn11, and Cldn18 remained cytoplasmically localized and the protein-unfolding pathway was activated in transgenic epidermal cells. Using a well-established two-stage chemical carcinogenesis model, we are now investigating the temporal and spatial changes in expression of these and other (Cldn1, Cldn12) Cldns that we have previously demonstrated to be important in epidermal differentiation and tumorigenesis in CDelta187 versus wild type (WT) mice. METHODS: The lower dorsal backskin of mice was treated topically with 7,12-dimethylbenz(a)anthracene (DMBA; 0.25 mg/ml in acetone) and following a 10-day incubation period, 12-O-tetradecanoyl-phorbol-13-acetate (TPA; 25 microg/ml in acetone) was applied three times a week to the same area. Backskin samples were dissected 2, 4, 6, 8 and 12 weeks after the initiation of the experimental protocol and immunohistochemistry was performed on sections using antibodies against the following: Cldn1, Cldn6, Cldn11, Cldn12, Cldn18, Ki67 (proliferation marker) and CD3 (immune infiltration marker). Strikingly, epidermal tumor formation was inhibited in CDelta187 as compared to WT animals. This is the first demonstration that alterations in Cldn structure and homeostasis may play a protective role against DMBA/TPA-induced skin tumors. Further investigation into the molecular mechanisms underlying this protective function is underway. Supported by CIHR

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4200.
Abstract 4204: Essential role of odontoblastic Smad4 in suppressing multiple keratocystic odontogenic tumors in mice
Authors: Gao Yuanrong , Yang Guan , Weng Tujun , Du Juan , Wang Xuejiu , Zhou Jian , Wang Songlin , Yang Xiao
Published: February 2011

Keratocystic odontogenic tumors (KCOT) are cystic epithelial neoplasias with a high recurrence rate. However, the molecular mechanisms underlying the initiation and progression of KCOTs are still largely unknown. Here, we show that specific ablation of Smad4 in odontoblasts unexpectedly resulted in spontaneous KCOTs in mice. The mutant mice exhibited malformed teeth characterized by fractured incisors and truncated molar roots. These abnormalities were mainly caused by disrupted odontoblast differentiation that led to irregular dentin formation. The cystic tumors arising from the reactivation of epithelial rests of Malassez (ERM), in which Smad4 remained intact, proliferated and formed stratified and differentiated squamous epithelia which exhibited a dramatic up-regulation of Hedgehog signaling. Odontoblasts which are responsive to TGF-β/BMP signals may produce signal molecules to inhibit the activation of ERM. Indeed, we observed a down-regulation of BMP signals from Smad4 mutant odontoblasts to adjacent Hertwig's epithelial root sheath (HERS). Intriguingly, KCOTs frequently emerged from Smad4-deficient ERMs in the keratinocyte specific Smad4 knockout mice, suggesting a novel mechanism that reciprocal TGF-β/BMP signaling between odontoblasts and HERS were required for tooth root development and suppression of KCOT formation. These findings provide insight into the genetic basis underlying KCOTs and important implications for new directions in KCOT treatments.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4204.
Abstract 4207: Pharmacodynamic comparisons of novel cryobiopsy instrumentation compared to standard techniques through comparative oncology modeling
Authors: Paoloni Melissa C. , Mazcko Christina , DiPaolo Tiziano , Parchment Ralph , Kinders Robert , Tomaszewski Joseph , Khanna Chand
Published: February 2011

The development of novel and targeted cancer drugs requires innovative clinical trial designs to define drug (pharmacokinetic) and host (pharmacodynamic) relationships early in the development process. For most new cancer agents there is increased emphasis on pharmacodynamic (PD) endpoints measured in tumor and surrogates as biomarkers of response. Accordingly, novel tissue collection procedures and instruments are needed to ensure that PD endpoint assessments are representative of their actual in vivo “state”. The Cassi Rotational Core Biopsy Device (Cryobiopsy) (Sanarus Medical, Inc, Pleasanton, California) is a biopsy instrument capable of incisional tissue collection and simultaneous freezing. In rodent xenograft models it demonstrated superiority in consistency for tumor analyte detection compared to traditional biopsy techniques. Whether this value would translate to the clinical setting was unknown. Use of naturally occurring cancers in pet dogs provides a model system to validate and optimize instrumentation techniques prior to use in human trials. A prospective clinical trial in dogs with lymphoma was conducted through the National Cancer Institute-Comparative Oncology Trials Consortium (NCI-COTC) to 1) determine if Cyrobiopsy provides sample quality advantages over conventional tru-cut, and open biopsy procedures, and 2) validate a “practice setting” Cryobiopsy Standard Operating Procedure (SOP) that could be followed by multiple users providing consistent high-quality biopsy samples. Ten dogs with newly diagnosed lymphoma enrolled. Cryobiopsy and tru-cut samples were collected in each patient from two lymph nodes in three planes via alternating techniques. A whole lymph node was then removed via excisional biopsy from the same dog. No adverse events were reported with Cryobiopsy or standard biopsy methods. The SOP for cryobiopsy collection of tissues was successfully implemented in a relevant clinical setting. Cryobiopsy collected samples successfully preserved target phospho-proteins (p-AKT: tAKT, p-ERK: tERK, p-MEK: tMEK) collected from tumor tissue. No difference in phospho-protein detection by Western was seen across biopsy techniques. In conclusion, this effort highlights the utility of the comparative approach to model medical device evaluation and PD biomarker assay validation in the clinical theatre.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4207.
Abstract 4208: Constitutive activation of Wnt/beta-catenin signaling induces uterine developmental defects
Authors: Wang Yongyi , Smits Ron , Franken Patrick , Jia Yundan , Grootegoed J. Anton , Burger Curt W. , Fodde Riccardo , Blok Leen J.
Published: February 2011

Background: Wnt/beta-catenin signaling plays a regulatory role in uterine development and function. To study this role of Wnt/beta-catenin signaling during embryogenesis in more detail, we employed an AmhR2 promoter-driven C-recombinase (Jamin et al., 2002) to conditionally inactivate the Apc gene in mesenchymal cells surrounding the müllerian duct. As a consequence of Apc inactivation, defects in the destruction complex are expected to result in the intracellular accumulation of beta-catenin and the subsequent constitutive activation of canonical Wnt signaling.

Methods: [Apc15Lox/15lox;AmhR2-Cre] conditional Apc knockout mice were generated. Cre expression and AmhR2 promotor activity was verified by staining for beta-galactosidase activity in [AmhR2-LacZ] and [AmhR2-Cre;ROSA26-LacZlox] reporter mice. Furthermore, recombination of the Apc gene was verified for different laser micro-dissected regions of the uterus, from 8-week-old mice, by PCR. Uterine defects were examined by immunohistochemical staining for various uterine markers.

Results: It was observed that the Cre-mediated Apc gene deletion mainly took place in the myometrial layers of the uterus. Recombination in the stroma and epithelium of the lumen and glands was low. Microscopically, the affected mice showed a significant reduction in the number of glands and a somewhat disorganized stroma. The main defects, however, were observed in the myometrial layer of the uterus, where clear disorganization of muscle fibres and in 50% of cases visible loss of musculature was apparent. As a consequence of these defects, the mice displayed reduced litter sizes and some mice were incapable of normal delivery.

Conclusion: AmhR2-Cre driven embryonic knock-down of Apc results in a defect of the myometrial layer of the uterus. Effects on the endometrium were observed to be less profound.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4208.
Abstract 421: Dystroglycan glycosylation status predicts Gleason grade and influences prostate tumor growth
Authors: Esser Alison K. , Weydert Christine J. , Meier Melissa M. , de Bernabe Daniel Beltran-Valero , Smith Brian J. , Cohen Michael B. , Campbell Kevin P. , Henry Michael D.
Published: February 2011

Dystroglycan, an extracellular matrix receptor, is expressed in many tissues including muscle, neural, adipose and epithelial where its function includes roles in polarity, basement membrane formation and tissue morphogenesis. Loss of dystroglycan expression has been shown in many epithelial cancers including prostate cancer yet the underlying mechanism remains unclear. Here, we investigate the role of DG in prostate cancer progression. We show that staining for the extracellular αDG subunit with the glycosylation-sensitive IIH6 anti-αDG antibody as well as the transmembrane βDG subunit are independent predictors of Gleason score in clinical prostate cancer specimens. In addition, increased αDG glycosylation due to expression of LARGE, a putative glycosyltransferase, in prostate cancer cell lines results in decreased tumor growth in prostate cancer xenografts. We determined that this reduction in growth is specific to the effect of LARGE on dystroglycan. Therefore our work has shown that the extent of αDG glycosylation predicts Gleason scores in prostate cancer and that LARGE dependent glycosylation of αDG regulates tumor growth.

This work is supported by a grant from the National Institutes of Health R01-CA130916

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 421.
Abstract 4210: Gsta4 modifies susceptibility to skin tumor development in mice and humans
Authors: Abel Erika L. , Angel Joe M. , Riggs Penny K. , Langfield Laura , Jiang Anna , Carbajal Steve , Lo Herng-Hsiang , Person Maria , Awasthi Yogesh , Wang Li-E , Strom Sara , Wei Qingyi , DiGiovanni John
Published: February 2011

The incidence of non-melanoma skin cancer (NMSC) is equivalent to that of all other human cancers combined, and genetic factors contribute to risk of the disease. Using genetic crosses of skin tumor promotion sensitive DBA/2 mice with relatively resistant C57BL/6 mice, loci that modify susceptibility to tumor promotion by 12-O-tetradecanoylphorbol-13-acetate (TPA) have been mapped to chromosomes (chr) 1, 2, 9, and 19. Here, we show that Glutathione S-transferase alpha 4 (Gsta4), which maps to skin tumor promotion susceptibility locus Psl1.2 on chr 9, was expressed at significantly different levels in the epidermis of C57BL/6 versus DBA/2 mice following treatment with diverse promoting agents. Gsta4 expression was dramatically upregulated in the epidermis of C57BL/6 mice, but not DBA/2 mice, following treatment with TPA, okadaic acid, chrysarobin, or ultraviolet light. Gsta4 deficient mice were more susceptible to skin tumor development in the two-stage skin carcinogenesis protocol providing compelling evidence that Gsta4 underlies the effect of Psl1.2 on susceptibility to skin tumor promotion by TPA. A number of polymorphisms were detected in the putative promoter region of Gsta4 in C57BL/6 versus DBA/2 mice, and ongoing studies are addressing the genetic basis of strain-specific expression of Gsta4 during tumor promotion. Finally, inheritance of polymorphisms in GSTA4 was associated with risk of NMSC in human populations, further supporting Gsta4/GSTA4 as a gene that modifies susceptibility to skin tumor development. Supported by NIH grant ES016623.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4210.
Abstract 4212: p53 null spindloid murine mammary tumors show features associated with human claudin-low tumors and enrichment for cancer stem cells
Authors: Herschkowitz Jason I. , Zhang Mei , Zhaow Wei , Murrow George W. , Edwards David , Knezevic Jana , Greene Stephanie B. , Medina Daniel , Perou Charles M. , Rosen Jeffrey M.
Published: February 2011

The claudin-low subtype is a recently identified new and rare molecular subtype of human breast cancer which we hypothesize may be enriched for cancer stem cells or tumor-initiating cells (TIC). These tumors express low levels of tight and adherens junction genes including claudin 3 and E-cadherin. Claudin-low tumors also often highly express markers associated with epithelial-mesenchymal transition (EMT) including EMT inducers Snail, Twist, Zeb1, and Zeb2. These tumors are also enriched in recently published signatures derived from human TICs and a sorted population enriched for human mammary stem cells. Using comparative genomics, we discovered that there are mouse mammary tumors that have similar gene expression characteristics as claudin-low human tumors and are also enriched in the human TIC signature. Tumors in this group were rare tumors which came from a number of distinct mouse models including the p53 null transplant model. We have now collected over forty more tumors from the p53 null model, a phenotypically heterogeneous tumor model, in order to identify tumors of different molecular subtypes including claudin-low/spindloid tumors that can be transplanted and expanded in vivo. Here we present a molecular characterization of the p53 null mammary tumor bank as compared to other mouse models and human breast tumor subtypes. Similar to human tumors, the p53 null tumors fall into multiple molecular groups, a basal-like subtype, a luminal subtype, and a claudin-low subtype. Like human breast tumors, the p53 null claudin-low tumors show high expression of EMT inducers. They also show low to absent expression of both claudin 3 and E-cadherin by microarray as well as immunostaining. These groups also contain distinct genomic copy number changes as assessed by array comparative genomic hybridization. Finally, we show by limiting dilution transplantation, that p53 null claudin-low tumors are significantly enriched for TICs as compared to the more common adenocarcinomas arising in the same model. In conclusion, p53 null claudin-low/spindloid tumors show features of human claudin-low tumors and they are enriched for TICs, which has yet to be demonstrated experimentally for human claudin-low tumors.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4212.
Abstract 4214: Stem cell antigen-1 (Sca1) modulates PI3K/PTEN signaling and mammary tumor cell survival
Authors: Upadhyay Geeta , Pollock Claire , Yin Yuzhi , Yuan Hongyan , Kopelovich Levi , Glazer Robert I.
Published: February 2011

Stem cell antigen-1 (Sca-1, Ly6A/E) represents two allelic forms of a GPI-anchored membrane protein that was first identified as a murine marker of bone marrow stem cells. Although Sca-1 is widely used to enrich for stem cells in many normal tissues, little is known about its function and associated signaling pathways in tumorigenesis. To explore this further, mammary carcinogenesis was induced in Sca-1+/EGFP mice that are heterozygous for Sca-1 and express GFP under the control of the Sca-1 locus. Induction of mammary tumorigenesis by progestin/DMBA treatment resulted in a marked increase of Sca-1 in the mammary gland at the initiation of tumorigenesis, as well as in the resulting tumors. To further investigate the function of Sca1, tumor cell line 34T was established from a primary adenocarcinoma, and sorted into Sca-1hi and Sca-1lo populations. These results revealed that Sca-1 expression related inversely with proliferation, as well as PTEN, PDK1, pT308Akt and pERK1/2 expression. Furthermore, reduction of Sca-1 in 34T cells by lentivirus-mediated RNAi reversed the proliferative, PTEN and kinase phenotype, and resulted in loss of their ability to proliferate as spheroid clusters in cell culture. Isografts of 34T/Sca-1hi and 34T/Sca-1lo cells in syngeneic mice indicated that Sca-1 was essential for tumorigenicity. These results provide evidence that Sca-1 confers a proliferative and survival advantage to mammary tumor cells, and demonstrates for the first time that Sca1 is associated with modulation of the PTEN/PDK1/Akt axis.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4214.
Abstract 4217: Contrasting mouse mammary cancer stem cells before and after EMT
Authors: Maurer Jochen , Hebbard Lionel , Castro David J. , Altman Yoav , Terskikh Alexey , Oshima Robert G.
Published: February 2011

We isolated mouse mammary cancer stem cells from a Wnt1-driven tumor model of aggressive breast cancer. These tumorigenic progenitor cells show expression of marker of both luminal (keratin 8) and myoepithelial (keratin 14) cells, express CD24, CD29 and CD49f surface markers. The K8+, K14+ double positive cells can be greatly enriched from less than 5% of the tumor to greater than 60% of the cultured cells in a 3D-culture system under hypoxic conditions. Transplantation of these cultured cells generated tumors with the differentiated morphology of the tumor of origin from a few as a single cell. In a 2D culture setting under normoxic conditions, double positive cells generate single positive differentiated derivates. Serial transplantation of the tumor generated from the cultured cells resulted in increasing growth rate reflected by reduced generation time from 52 days to 21 days after four passages. The fast-growing tumors were strongly positive for vimentin, negative for K14 and few cells expressed K8. Analysis of the cells in 2D revealed a fibroblast-like growth pattern. When grown in 3D, the cells do not form spheroids but rather grow in an invasive pattern in Matrigel. This tumor line has undergone an epithelial to mesenchymal transition (EMT). These cells also generate tumors from single cell transplants but do not generate heterogeneous tumors.

In summary, we have succeeded in cultivating a mammary cancer stem cell, demonstrated its self renewal capacity and potential for differentiation both in vivo and in culture. Furthermore, we have isolated an EMT derivative that is tumorgenic but appears to have lost the potential for self limiting differentiation. This demonstrates that tumorigenic cells with severely restricted capacity for differentiation can be derived from a cancer stem cell. Potential therapies based on the potential of cancer stem cells to differentiate may need to be applied at very early stages of the development of breast cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4217.
Abstract 4225: Expression of NANOG in a prostate cancer cell line increases CD24 expression and enhances cell invasion
Authors: Fowler Macie , Glass Jonathan , Yin Hong
Published: February 2011

The transcription factor NANOG is critical for the maintenance of embryonic stem cell properties including self-renewal and pluripotency. NANOG performs these functions by regulating the expression of genes required for the preservation of the stem cell phenotype. Introduction of NANOG and other embryonic stem cell genes has successfully established disease-specific induced pluripotent stem cells in several types of human cancers. Although the expression of NANOG has been documented in cancer cells, the function of NANOG in cancer has not been extensively investigated.

We hypothesized that NANOG plays a role in prostate cancer cell biology based on our observation of NANOG protein expression in prostate cancer cell lines. To test this hypothesis, we transduced the PC3 prostate cancer cell line with a lentivirus capable of directing the expression of NANOG. A stable cell line containing the NANOG expression cassette was established by selection with puromycin, and expression of NANOG protein was verified by Western blot analysis. Analysis of stem cell surface markers by flow cytometry in the PC3-NANOG cells and PC3 cells transduced with empty virus revealed an increase in the percentage of CD24 positive cells in the PC3-NANOG sample as compared with the control. In addition, the density of CD24 per cell appeared to increase. This increase in CD24 expression was confirmed by Western blot analysis.

In multiple cancers expression of CD24, a mucin-like adhesion protein, correlates with invasion and metastatic potential. Therefore, we conducted an invasion assay to assess the ability of PC3-NANOG cells to invade through a matrix assaying invasion by migration of cells from one chamber of a bicameral chamber through a porous membrane. The results showed that PC3-NANOG cells exhibited a 30-40% increase in invasion as compared to the control cells. (p<0.001). These results suggest that expression of NANOG in a prostate cancer cell line contributes to increased invasive capacity, possibly through enhanced expression of CD24. Therefore, NANOG could be a potential mediator of prostate cancer cell invasion and maneuvers to decrease NANOG expression could be a new therapeutic target for treatment of prostate cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4225.