Murine Ovarian Cancer Cell Line Research Articles

Evaluation of microparticulate ovarian cancer vaccine via transdermal route of delivery

Ovarian cancer is the fifth most commonly occurring malignancy in women, with the highest mortality rate among all the gynecological tumors. Microparticulate vaccine can serve as an immunotherapeutic approach with a promising antigenic delivery system without a need for conventional adjuvants. In this study, a microparticulate vaccine using whole cell lysate of a murine ovarian cancer cell line, ID8 was prepared by spray drying. Further, the effect of interleukins (ILs) such as IL-2 and IL-12 was evaluated in a separate study group by administering them with vaccine particles to enhance the immune response. The vaccine microparticles were administered to C57BL/6 female mice via transdermal alone and in combination with the oral route. The transdermal vaccine was delivered using a metallic microneedle device, AdminPen™. Orally administered microparticles also included an M-cell targeting ligand, Aleuria aurantia lectin, to enhance the targeted uptake from microfold cells (M-cells) in Peyer's patches of small intestine. In case of combination of routes, mice were given 5 transdermal doses and 5 oral doses administered alternatively, beginning with transdermal dose. At the end of vaccination, mice were challenged with live tumor cells. Vaccine alone resulted in around 1.5 times tumor suppression in case of transdermal and combination of routes at the end of 15th week when compared to controls. Inclusion of interleukins resulted in 3 times tumor suppression when administered with transdermal vaccine and around 9 times tumor suppression for the combination route of delivery in comparison to controls. These results were further potentiated by serum IgG, IgG1 and IgG2a titers. Moreover, CD8+ T-cell, CD4+ T-cell and NK (natural killer) cell populations in splenocytes were elevated in case of vaccinated mice. Thus, vaccine microparticles could trigger humoral as well as cellular immune response when administered transdermally and via combination of route of delivery. However overall, vaccine administered with interleukins, via combination of route, was found to be the most efficacious to suppress the tumor growth and lead to a protective immune response.

Effects of Kras activation and Pten deletion alone or in combination on MUC1 biology and epithelial-to-mesenchymal transition in ovarian cancer.

Mucin1 (MUC1) is an epithelial glycoprotein overexpressed in ovarian cancer and actively involved in tumor cell migration and metastasis. Using novel in vitro and in vivo MUC1-expressing conditional (Cre-loxP) ovarian tumor models, we focus here on MUC1 biology and the roles of Kras activation and Pten deletion during cell transformation and epithelial-to-mesenchymal transition (EMT). We generated several novel murine ovarian cancer cell lines derived from the ovarian surface epithelia (OSE) of mice with conditional mutations in Kras, Pten or both. In addition, we also generated several tumor-derived new cell lines that reproduce the original tumor phenotype in vivo and mirror late stage metastatic disease.Our results demonstrate that de novo activation of oncogenic Kras does not trigger increased proliferation, cellular transformation or EMT and prevents MUC1 upregulation. In contrast, Pten deletion accelerates cell proliferation, triggers cellular transformation in vitro and in vivo and stimulates MUC1 expression. Ovarian tumor-derived cell lines MKP-Liver and MKP-Lung cells reproduce in vivo EMT and represent the first immune competent mouse model for distant hematogenous spread. Whole genome microarray expression analysis using tumor and OSE-derived cell lines reveals a 121 gene signature associated with EMT and metastasis. When applied to n=542 cases from the ovarian cancer TCGA dataset, the gene signature identifies a patient subset with decreased survival (p=0.04). Using an extensive collection of novel murine cell lines we have identified distinct roles for Kras and Pten on MUC1 and EMT in vivo and in vitro. The data has implications for future design of combination therapies targeting Kras mutations, Pten deletions and MUC1 vaccines.

Abstract 1146: Global profiling of SPARC-regulated metabolic pathways in ovarian cancer

Abstract We have previously reported the tumor suppressor effect of SPARC in ovarian cancer through inhibiting cancer cell growth and their interactions within the peritoneal milieu. In the present study, we sought to determine the effect of SPARC on metabolic perturbations associated with ovarian cancer using a syngeneic murine ovarian cancer model in SPARC knockout (KO) mice and their wildtype (WT) counterparts. Murine ID8 ovarian cancer cell line were injected intraperitoneally in SPARC KO and WT mice. Matched intraperitoneal tumor tissue, and ascitic fluid were harvested 6 weeks post-injection of ID8 cells and were subjected to global biochemical metabolomic profiling. In tandem, WT and KO tumors were dissected by LCM-microdissected and were subjected to gene expression profiling. Metabolomic profiling of SPARC KO tumors and ascites revealed significantly altered metabolites associated with glucose, energy, amino acid, and lipid metabolism, as well as redox homeostasis. Integrated transcriptome and metabolome analysis of the top significantly upregulated genes and metabolites in the KO compared to WT tumors and ascitic fluid revealed that the major pathways upregulated in absence of SPARC are those involved in: conversion of glucose to acetyl CoA and entry into the citric acid (TCA) cycle, respiratory electron transport and oxidative phosphorylation (SUCLG2; NDUFAB1; ATP5F1; UQCRH; ATP5H; COX5B; NDUFV1; ATP5O; IDH3B/ succinate, fumarate and pyruvate), protein metabolism (EIF5A; PREB; EIF4H; DAD1; STT3A; RPL4; SUMO1; CCT4; CCT2; IGFBP5; HSPA5; EIF3A; EIF4B; RPS19; EIF3E/ mannose; N-acetylneuraminate; N-glycolylneuraminate; glutamate; spermidine), fatty acid beta oxidation (HADH; TPI1; LPL/glycerol), purine nucleotides de novo biosynthesis and salvage (ATP5F1; ATP5H; PAICS; ATP6V1G1/ aspartate; glycine; glutamate; fumarate). Together, these data provide novel insight on the molecular mechanisms of the SPARC-induced metabolic perturbation associated with ovarian cancer that can be translated into diagnostic and prognostic biomarkers of the disease. Citation Format: Sherine Taylor, Christian Sanchez, Amna Adrees, Hale Nur Ozbek, Harjapjit Sahni, Neveen A. Said. Global profiling of SPARC-regulated metabolic pathways in ovarian cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1146. doi:10.1158/1538-7445.AM2015-1146

Abstract 4072: Embryonic rest hypothesis of cancer development revisited: functional gonadotropic hormone receptors are expressed by normal and malignant hematopoietic cells and functional erythropoietin receptor is expressed by germline-derived tumors

Abstract Background: The existence in adult tissues of developmentally early stem cells with broader specification potential may suggest the presence of embryonic primordial germ cell (PGC) remnants in post-natal organs. To support this small, quiescent stem cells (VSELs) that express several markers of PGCs reside in adult murine bone marrow (BM) (Leukemia 2010;24:1450), and like PGCs, are kept quiescent by erasure of imprinting on paternally imprinted genes (Leukemia 2009;23:2042). As reported hematopoietic stem/progenitor cells (HSPCs) can become specified from a population of migrating PGCs isolated from embryos (Blood 1995;86:463) as well as from adult bone marrow VSELs (Leukemia 2011;25,1278). In support of this intriguing possibility, HSPCs and PGCs are both highly migratory populations of stem cells, and specification of the first primitive HSPCs in yolk sac blood islands as well as the origin of definitive HSPCs in the aorta-gonado-mesonephros region are chronologically and anatomically correlated with the developmental migration of PGCs in extra- and intra-embryonic tissues on their way to the genital ridges. Hypothesis: Based on these observations, we have hypothesized that PGC-derived cells as well as HSPCs share some common receptors, and we tested the expression of gonadotropic hormone receptors (GHR) and erythropoietin receptor (EpoR) on HSPCs and PGC-derived cells, respectively. Materials and Methods. We employed RT-PCR studies to evaluate the expression of GHR on normal and malignant HSPCs, whereas we evaluated the expression of EpoR on teratocarcinoma and ovarian cancer cell lines. The functionality of these receptors was tested by chemotaxis, adhesion, and proliferation assays, and we performed signal transduction studies employing specific ligands for gonadal receptors to stimulate HSPCs and erythropoietin (EPO) to stimulate germline-derived cells. Results. We observed the expression of functional FSH, LH, PRL, estrogen, and androgen receptors on normal murine and human HSPCs and in leukemia cell lines. At the same time, we observed the presence of functional EpoRs on murine and human teratocarcinoma cells and ovarian cancer cell lines. Conclusions. Our data provide further evidence for the existence of a developmental link between germline and hematopoiesis and shed new light on the developmental hierarchy of the stem cell compartment in adult tissues and possibility that some malignancies may develop from embryonic remnants. These observations also have important practical implications: i) pituitary gonadal hormones could be employed in selected cases of BM failure to stimulate hematopoiesis and ii) EPO treatment (e.g., because of anemia after chemotherapy) should be avoided in patients with germline malignancies. Citation Format: Malwina Suszynska, Katarzyna Mierzejewska, Agata Poniewierska-Baran, Ahmed Abdelbasit Ismail, Gabriela Schneider, Pranesh Gunjal, Janina Ratajczak, Sham S. Kakar, Magda Kucia, Mariusz Z. Ratajczak. Embryonic rest hypothesis of cancer development revisited: functional gonadotropic hormone receptors are expressed by normal and malignant hematopoietic cells and functional erythropoietin receptor is expressed by germline-derived tumors. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4072. doi:10.1158/1538-7445.AM2015-4072

Ascites Increases Expression/Function of Multidrug Resistance Proteins in Ovarian Cancer Cells.

Chemotherapy resistance is the major reason for the failure of ovarian cancer treatment. One mechanism behind chemo-resistance involves the upregulation of multidrug resistance (MDR) genes (ABC transporters) that effectively transport (efflux) drugs out of the tumor cells. As a common symptom in stage III/IV ovarian cancer patients, ascites is associated with cancer progression. However, whether ascites drives multidrug resistance in ovarian cancer cells awaits elucidation. Here, we demonstrate that when cultured with ascites derived from ovarian cancer-bearing mice, a murine ovarian cancer cell line became less sensitive to paclitaxel, a first line chemotherapeutic agent for ovarian cancer patients. Moreover, incubation of murine ovarian cancer cells in vitro with ascites drives efflux function in these cells. Functional studies show ascites-driven efflux is suppressible by specific inhibitors of either of two ABC transporters [Multidrug Related Protein (MRP1); Breast Cancer Related Protein (BCRP)]. To demonstrate relevance of our findings to ovarian cancer patients, we studied relative efflux in human ovarian cancer cells obtained from either patient ascites or from primary tumor. Immortalized cell lines developed from human ascites show increased susceptibility to efflux inhibitors (MRP1, BCRP) compared to a cell line derived from a primary ovarian cancer, suggesting an association between ascites and efflux function in human ovarian cancer. Efflux in ascites-derived human ovarian cancer cells is associated with increased expression of ABC transporters compared to that in primary tumor-derived human ovarian cancer cells. Collectively, our findings identify a novel activity for ascites in promoting ovarian cancer multidrug resistance.

The PARP1 inhibitor BMN 673 exhibits immunoregulatory effects in a Brca1−/− murine model of ovarian cancer

Familial breast and ovarian cancer are often caused by inherited mutations of BRCA1. While current prognoses for such patients are rather poor, inhibition of poly-ADP ribose polymerase 1 (PARP1) induces synthetic lethality in cells that are defective in homologous recombination. BMN 673 is a potent PARP1 inhibitor that is being clinically evaluated for treatment of BRCA-mutant cancers. Using the Brca1-deficient murine epithelial ovarian cancer cell line BR5FVB1-Akt, we investigated whether the antitumor effects of BMN 673 extend beyond its known pro-apoptotic function. Administration of modest amounts of BMN 673 greatly improved the survival of mice bearing subcutaneous or intraperitoneal tumors. We thus hypothesized that BMN 673 may influence the composition and function of immune cells in the tumor microenvironment. Indeed, BMN 673 significantly increases the number of peritoneal CD8+ T cells and NK cells as well as their production of IFN-γ and TNF-α. These data suggest that the cell stress caused by BMN 673 induces not only cancer cell-intrinsic apoptosis but also cancer cell-extrinsic antitumor immune effects in a syngeneic murine model of ovarian cancer. BMN 673 may therefore serve as a promising adjuvant therapy to immunotherapy to achieve durable responses among patients whose tumors harbor defects in homologous recombination.

PD-L1 blockade and upregulation in an ovarian cancer treatment model (TUM2P.1017)

Abstract Objective: We explored mechanisms of PD-L1 upregulation in ovarian cancer cells and tested in vivo the efficacy of intraperitoneal anti-PD-L1 therapy in two different ovarian cancer mouse models. Methods: We have derived several novel murine ovarian cancer cell lines from orthotopic ovarian tumors of triple transgenic mice. 129x SvJ and C57Bl/6 tumor-bearing mice were treated with 200 μg anti-PD-L1 antibody (or rat IgG as control) every two weeks for three doses. Immune gene profiling of splenocytes collected at necropsy was performed using 561 Nanostring probes. Results: Cell cycle analysis of in vitro cultured tumor cells demonstrates that PD-L1 expression increases preferentially on cells in G2/M cells. Exposure to cisplatin modifies PD-L1 levels, although the effect varies according to tumors’ baseline susceptibility. In vivo, we observed murine PD-L1 upregulation on ascites resident tumor cells, an effect reproduced ex vivo upon exposure of tumor cells to ascites fluid. PD-L1 blockade triggers increase in survival in both preclinical models with immune gene signatures pointing to cytotoxic anti-tumor immune response. Conclusion: PD-L1 expression increases in response to inflammatory stimuli from cell-free ascites and shows preference for dividing cells. PD-L1 upregulation varies according to tumor cells’ susceptibility to cisplatin. PD-L1 blockade increases systemic T cell responses and intratumoral T cell accumulation suggesting therapeutic potential in ovarian cancer.

Folate receptor-targeted multimodality imaging of ovarian cancer in a novel syngeneic mouse model.

A new transplantable ovarian tumor model is presented using a novel folate receptor (FR) positive, murine ovarian cancer cell line that emulates the human disease and induces widespread intraperitoneal (i.p.) tumors in immunocompetent mice within 4–8 weeks of implantation. Tumor development was monitored using a new positron emission tomography (PET) FR-targeting reporter with PET/computerized tomography (PET/CT) and fluorescence molecular tomography (FMT) using a commercial FR-targeting reporter. Conventional structural magnetic resonance imaging (MRI) was also performed. Adult female C57BL/6 mice were injected i.p. with 6 × 106 MKP-L FR+ cells. Imaging was performed weekly beginning 2 weeks after tumor induction. The albumin-binding, FR-targeting ligand cm09 was radiolabeled with the positron emitter 68Ga and used to image the tumors with a small animal PET/CT. The FR-reporter FolateRSense 680 (PerkinElmer) was used for FMT and flow cytometry. Preclinical MRI (7 T) without FR-targeting was compared with the PET and FMT molecular imaging. Tumors were visible by all three imaging modalities. PET/CT had the highest imaging sensitivity at 3–3.5 h postadministration (mean %IA/g mean > 6) and visualized tumors earlier than the other two modalities with lower kidney uptake (mean %IA/g mean < 17) than previously reported FR-targeting agents in late stage disease. FMT showed relatively low FR-targeted agent in the bladder and kidneys, but yielded the lowest anatomical image resolution. MRI produced the highest resolution images, but it was difficult to distinguish tumors from abdominal organs during early progression since a FR-targeting MRI reporter was not used. Nevertheless, there was good correlation of imaging biomarkers between the three modalities. Tumors in the mouse ovarian cancer model could be detected using FR-targeted imaging as early as 2 weeks post i.p. injection of tumor cells. An imaging protocol should combine one or more of the modalities, e.g., PET/CT or PET/MRI for optimal tumor detection and delineation from surrounding tissues.

CXCL12/CXCR4 blockade by oncolytic virotherapy inhibits ovarian cancer growth by decreasing immunosuppression and targeting cancer-initiating cells.

Signals mediated by the chemokine CXCL12 and its receptor CXCR4 are involved in the progression of ovarian cancer through enhancement of tumor angiogenesis and immunosuppressive networks that regulate dissemination of peritoneal metastasis and development of cancer-initiating cells (CICs). In this study, we investigated the antitumor efficacy of a CXCR4 antagonist expressed by oncolytic vaccinia virus (OVV) against an invasive variant of the murine epithelial ovarian cancer cell line ID8-T. This variant harbors a high frequency of CICs that form multilayered spheroid cells and express the hyaluronan receptor CD44, as well as stem cell factor receptor CD117 (c-kit). Using an orthotopic ID8-T tumor model, we observed that i.p. delivery of a CXCR4 antagonist-expressing OVV led to reduced metastatic spread of tumors and improved overall survival compared with oncolysis alone. Inhibition of tumor growth with the armed virus was associated with efficient killing of CICs, reduced expression of ascitic CXCL12 and vascular endothelial growth factor, and decreases in i.p. numbers of endothelial and myeloid cells, as well as plasmacytoid dendritic cells. These changes, together with reduced recruitment of T regulatory cells, were associated with higher ratios of IFN-γ(+)/IL-10(+) tumor-infiltrating T lymphocytes, as well as induction of spontaneous humoral and cellular antitumor responses. Similarly, the CXCR4 antagonist released from virally infected human CAOV2 ovarian carcinoma cells inhibited peritoneal dissemination of tumors in SCID mice, leading to improved tumor-free survival in a xenograft model. Our findings demonstrate that OVV armed with a CXCR4 antagonist represents a potent therapy for ovarian CICs with a broad antitumor repertoire.

Abstract 2823: Low merlin level as a biomarker for sensitivity of ovarian cancer cell lines to FAK inhibition

Abstract Focal adhesion kinase (FAK) is a cytoplasmic tyrosine kinase that undergoes gene amplification in &amp;gt;20% of serous ovarian cancers. In addition to increased tumor growth and spread, ovarian cancer patients with FAK amplification have a poorer prognosis with decreased overall survival. Merlin, a product of the NF2 tumor suppressor gene, is being evaluated as a biomarker for sensitivity to FAK inhibition in human clinical trials for malignant mesothelioma. As it remains undetermined whether linkages exist between merlin and FAK in other tumor types, we evaluated nine human and two murine ovarian cancer cell lines with sub-micromolar levels of FAK inhibitor (PF-271) for effects on anchorage-independent cell growth. Cells were identified as sensitive (OVCAR3, OVCAR8, HEY, ID8-IP), intermediate (A2780, IGROV1), or resistant (OVCAR10, IGROV1-IP, SKOV3, SKOV3-IP, 5009) to FAK inhibition. Notably, merlin protein levels were high in all resistant cell lines, moderate in intermediate cell lines, and low or undetectable in sensitive cell lines. Oral FAK inhibitor administration reduced orthotopic tumor growth of sensitive (ID8-IP, low merlin) but not resistant (5009, high merlin) murine ovarian carcinoma cells. However, stable knockdown of merlin expression in resistant SKOV3-IP and OVCAR10 human ovarian carcinoma cells did not induce sensitivity to FAK inhibition in vitro. These results support the notion that high merlin expression is correlated with a FAK-inhibitor resistant phenotype, likely through an indirect mechanistic linkage. Nevertheless, merlin protein levels may serve as a biomarker to predict ovarian cancer sensitivity or resistance to FAK inhibitor treatment. Supported by NIH CA102310 Citation Format: Nina R. Shah, Isabelle Tancioni, Kristy K. Ward, Christine Lawson, Xiao Lei Chen, Nichol L.G. Miller, Florian J. Sulzmaier, Sean Uryu, David D. Schlaepfer. Low merlin level as a biomarker for sensitivity of ovarian cancer cell lines to FAK inhibition. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2823. doi:10.1158/1538-7445.AM2014-2823

Abstract 4976: Novel ovarian cancer transplantable models generated from MUC1KrasPten tumors show in vitro and in vivo heterogeneity

Abstract Introduction: Ovarian epithelial tumors are highly heterogeneous. Patients are diagnosed late, when tumors have spread to the surrounding tissues, most often to the omentum. Despite optimal removal and response to therapy, the tumors often recur. Personalized medicine approaches often require molecular profiling of tumors, for patient selection and to predict response to therapy. Given intratumor heterogeneity, identification of tumor sites that are best to select for profiling is still up for debate. Approach: We recently developed triple transgenic (MUC1KrasPten.Tg) mice that develop orthotopic MUC1-expressing endometrioid ovarian tumors. The tumors develop in the ovaries and spread throughout the peritoneal cavity, closely mirroring the human disease. Using tumor cells isolated from either the MUC1KrasPten primary ovarian tumor (MKP-T) or the liver implant (MKP-L), we generated several new murine ovarian cancer cell lines which express human MUC1 as self, while simultaneously carrying constitutively active oncogenic Kras and defective Pten tumor suppressor. Results: MKP-T and MKP-L showed variable expression pattern of MUC1, EpCAM, folate receptor, ALDH, cytokeratin and vimentin, demonstrating the relationship between the anatomical location of each originating tumor and the cell line's in vitro phenotype. Unlike the MKP-L cells, the MKP-T cells display loss of K-ras heterozygosity, suggesting that migration to a metastatic site was an early event. Although both cell lines can grow IP tumors in syngeneic triple transgenic MUC1KrasPten.Tg, they carry distinct in vivo phenotypes. MKP-T cells multiply at higher rate and generate larger loco- regional tumors. In contrast, the MKP-L cells, derived from a metastatic site, have a slower growth rate but spread throughout the peritoneal cavity, undergo epithelial-mesenchymal transition (EMT) and trigger distant metastases to the lungs(MKP-Lng). In line with their Kras status, MEK 1/2 inhibitor AZD6244 (currently tested in several Phase II clinical trials) is more effective on MKP-T cells than on MKP-L and MKP-Lng cells in vitro, suggesting that metastatic tumor cells may be more resistant to MEK1/2 inhibitiors. Conclusions: Using novel murine tumor cell populations, we reproduce intratumoral heterogeneity and demonstrate that in vitro and in vivo biological properties vary with the location of originating tumor. Most importantly, we show that cells derived from metastatic sites, which are more likely to reproduce the characteristic of the recurrent tumors, have an increased metastatic potential and reduced response to therapeutic drugs. These results suggest that molecular profiling of tumors needs to focus on multiple tumor sites and that in ovarian cancer, distant tumor implants may be particularly important. Supported by NIH R01 CA163462 and DOD OC093429. Citation Format: Lixin Zhang, Raluca Budiu, Joan Brozick, Anda M. Vlad. Novel ovarian cancer transplantable models generated from MUC1KrasPten tumors show in vitro and in vivo heterogeneity. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4976. doi:10.1158/1538-7445.AM2014-4976

Abstract 1653: Complement roles in endometriosis and endometriosis-associated ovarian cancer

Abstract Introduction: Endometriosis is a largely benign, chronic inflammatory disease defined by the presence of endometrial-like glands surrounded by stroma. Epidemiologic studies suggest that endometriosis is an independent risk factor for endometrioid and clear cell epithelial ovarian tumors, collectively called endometriosis-associated ovarian cancers (EAOC). Histopathology findings demonstrate that EAOC occur in the presence of atypical endometriosis (AE), often found in direct continuity with the tumor, suggesting AE as the transitioning entity from benign lesions to malignant variants. Although it is widely accepted that chronic inflammation drives cancer, immune deregulation in chronic precursor lesions to ovarian cancer have not been studied in a systematic way. Experimental procedure: We extracted RNA from 135 paraffin tissue blocks comprising of normal endometrium (n=32), benign endometriosis consisting of ovarian and extra ovarian endometriosis cases (n=30,) atypical endometriosis (n=15) and EAOC, (n=43). Serous tumors (n=15) were included as non-endometriosis associated controls. Using Nanostring and the nCounter® GX Human Immunology Kit, we profiled a total of 511 immune genes. Cluster analyses and differential expressions (DE) were calculated using EdgeR. Protein expression of candidate proteins was validated with immunohistochemistry (IHC). To identify mechanisms of complement activation during early stages of genomic instability, we used murine cell lines derived from mice with conditional mutations in Kras and Pten pathways. Results: Nanostring immune gene expression profile eveal the predominant role of adaptive immunity and of the adaptive-innate immune cross-talk. The complement pathway was most prominently expressed, suggesting its roles as one of the major immune pathways involved in the transition from chronic endometriosis to atypical (premalignant) endometriosis and to EAOC. Complement pathway genes were upregulated in human endometriosis and atypical endometriosis. Tissue deposition of several complement components and changes in peripheral blood were confirmed by IHC and ELISA, respectively. Genomic instability in murine ovarian cancer cell lines with conditional mutations resulted in upregulation of complement genes expression in epithelial cells, but without an advantage on cell death. These findings further support a paradigm shift on complement roles in cancer, suggesting its pro-tumorigenic roles. Conclusions: We performed the first comprehensive gene profile of the tissue immune microenvironment in benign endometriosis, EAOC and precursor lesions and identified the previously unrecognized roles for the complement pathway. Complement activation may be an early trigger of inflammation and an early link between epithelium and immune environment. These findings have high translational potential for immune therapy and prevention in EAOC. Citation Format: Swati Maruti Suryawanshi, Xin Huang, Raluca Budiu, SungHwan Kim, George Tseng, Esther Elishaev, Marcia Klein-Patel, Ted Lee, Suketu Mansuria, Robert Edwards, Anda Vlad. Complement roles in endometriosis and endometriosis-associated ovarian cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1653. doi:10.1158/1538-7445.AM2014-1653

Expression of the erythropoietin receptor by germline-derived cells - further support for a potential developmental link between the germline and hematopoiesis.

BackgroundExpressing several markers of migrating primordial germ cells (PGCs), the rare population of quiescent, bone marrow (BM)-residing very small embryonic-like stem cells (VSELs) can be specified like PGCs into hematopoietic stem/progenitor cells (HSPCs). These two properties of VSELs support the possibility of a developmental origin of HSPCs from migrating PGCs.MethodsTo address a potential link between VSELs and germ line cells we analyzed by RT-PCR and FACS expression of erythropoietin receptor (EpoR) on murine bone marrow- and human umbilical cord blood-derived VSELs, murine and human teratocarcinoma cell lines and human ovarian cancer cells. A proper gating strategy and immunostaining excluded from FACS analysis potential contamination by erythroblasts. Furthermore, the transwell chemotaxis assays as well as adhesion and signaling studies were performed to demonstrate functionality of erythropoietin - EpoR axes on these cells.ResultsWe report here that murine and human VSELs as well as murine and human teratocarcinoma cell lines and ovarian cancer cell lines share a functional EpoR.ConclusionsOur data provide more evidence of a potential developmental link between germline cells, VSELs, and HSCs and sheds more light on the developmental hierarchy of the stem cell compartment in adult tissues.

Analyses of merlin/NF2 connection to FAK inhibitor responsiveness in serous ovarian cancer

ObjectiveFocal adhesion kinase (FAK) is overexpressed in serous ovarian cancer. Loss of merlin, a product of the neurofibromatosis 2 tumor suppressor gene, is being evaluated as a biomarker for FAK inhibitor sensitivity in mesothelioma. Connections between merlin and FAK in ovarian cancer remain undefined. MethodsNine human and two murine ovarian cancer cell lines were analyzed for growth in the presence of a small molecule FAK inhibitor (PF-271, also termed VS-6062) from 0.1 to 1μM for 72h. Merlin was evaluated by immunoblotting and immunostaining of a human ovarian tumor tissue array. Growth of cells was analyzed in an orthotopic tumor model and evaluated in vitro after stable shRNA-mediated merlin knockdown. ResultsGreater than 50% inhibition of OVCAR8, HEY, and ID8-IP ovarian carcinoma cell growth occurred with 0.1μM PF-271 in anchorage-independent (p<0.001) but not in adherent culture conditions. PF-271-mediated reduction in FAK Y397 phosphorylation occurred independently of growth inhibition. Suspended growth of OVCAR3, OVCAR10, IGROV1, IGROV1-IP, SKOV3, SKOV3-IP, A2780, and 5009-MOVCAR was not affected by 0.1μM PF-271. Merlin expression did not correlate with serous ovarian tumor grade or stage. PF-271 (30mg/kg, BID) did not inhibit 5009-MOVCAR tumor growth and merlin knockdown in SKOV3-IP and OVCAR10 cells did not alter suspended cell growth upon PF-271 addition. ConclusionsDifferential responsiveness to FAK inhibitor treatment was observed. Intrinsic low merlin protein level correlated with PF-271-mediated anchorage-independent growth inhibition, but reduction in merlin expression did not induce sensitivity to FAK inhibition. Merlin levels may be useful for patient stratification in FAK inhibitor trials.

Abstract B66: Novel ovarian cancer transplantable models generated from MUC1KrasPten tumors show different in vitro and in vivo biological behaviors

Abstract Introduction: Sustained improvement in the development of new therapeutic approaches in ovarian cancer depends in part on the availability of adequate preclinical models for in vivo testing of treatment efficacy. We recently developed triple transgenic (MUC1KrasPten.Tg) mice expressing human MUC1 oncoprotein as self and carrying the conditional K-rasG12D oncoallele (loxP-Stop-loxP-K-rasG12D/+) and the floxed Pten gene (PtenloxP/loxP). The MUC1KrasPten.Tg mice develop MUC1-expressing endometrioid ovarian tumors that closely mirror the human disease and respond to human MUC1-based immune therapy. Compared to the KrasPten mice, tumors from MUC1KrasPten.Tg mice had a higher potential for loco-regional spread, suggesting active MUC1 involvement in local and distant tumor spread. Approach: In order to study in vitro and in vivo MUC1 roles in tumor growth and metastasis and interactions between MUC1 signaling and Kras and Pten pathways, we generated several new murine ovarian cancer cell lines. These cell lines express human MUC1 as self, while simultaneously carrying constitutively active oncogenic Kras and defective Pten tumor suppressor. The originating cells were derived from either the MUC1KrasPten primary ovarian tumor or the liver implant via trypsinization into single cell suspension. Cells were cultured in vitro for at least 20 passages to generate the stable MKP-T (from primary tumor) and MKP-L (from liver metastasis) ovarian cancer cell lines. Clonal populations were obtained via limiting dilution assays. Results: Although derived from the same host, the MKP-T and MKP-L cells showed different K-ras status reflective of tumor heterogeneity in vivo. Unlike the MKP-L cells, the MKP-T cells display loss of K-ras heterozygosity. MKP-T and MKP-L showed variable expression pattern of MUC1, EpCAM, folate receptor, ALDH, cytokeratin and vimentin, demonstrating how the anatomical location of each originating tumor influences the cell line's in vitro phenotype. Furthermore, although both cell lines can grow IP tumors in syngeneic triple transgenic MUC1KrasPten.Tg, single transgenic MUC1.Tg as well as wild-type C57BL/6J-bgJ mice, they carry distinct in vivo phenotypes. MKP-L cells grow slower in vitro (doubling time 27.5 hours) and in vivo and trigger distant metastases to the lungs. MKP-T cells multiply at higher rate in vitro (doubling time 13.2 hours) and in vivo and generate larger loco- regional tumors. Two sub-lines (MKP-T-2F8-Asc and MKP-L-Lng) derived from MKP-T ascites and MKP-L lung metastasis, respectively, by in vivo clonal selection, showed stable and high MUC1 expression, further demonstrating its in vivo roles for both loco-regional as well as distant spread. In line with their Kras status, MEK 1/2 inhibitor AZD6244 (currently tested in several Phase II clinical trials) showed more inhibition on MKP-T cells than on MKP-L cells in vitro, providing support for its use in this preclinical models. Conclusions: We have generated several novel murine cancer cell lines and characterized the first immune competent transplantable ovarian cancer model expressing human MUC1 as a transgene. The cell lines show various levels of MUC1 and display different metastatic behaviors in vitro and in vivo. MKP-L cells metastasize to the lungs and represent the first in vivo model for distant metastasis in ovarian cancer. Our novel preclinical models are uniquely suited for in vivo combination therapies targeting MUC1, Kras and Pten/PI3K pathways and provide new tools for elucidating the biological behaviors of ovarian cancer cells both in vitro and in vivo. Citation Format: Lixin Zhang, Raluca Budiu, Joan Brozick, Anda Vlad. Novel ovarian cancer transplantable models generated from MUC1KrasPten tumors show different in vitro and in vivo biological behaviors. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr B66.

Intra-Peritoneal Hyperthermia Combining α-Galactosylceramide in the Treatment of Ovarian Cancer

The purpose of this study was to investigate the anti-tumor effect and potential mechanisms of i.p. hyperthermia in combination with α-galactosylceramide (α-GalCer) for the treatment of ovarian cancer. In this study, immuno-competent tumor models were established using murine ovarian cancer cell lines and treated with i.p. hyperthermia combining α-GalCer. Th1/Th2 cytokine expression profiles in the serum, NK cell cytotoxicity and phagocytic activities of dendritic cells (DCs) were assayed. We also analyzed the number of CD8+/IFN-γ+ tumor specific cytotoxic T cells, as well as the tumor growth based on depletion of lymphocyte sub-population. Therapeutic effect on those ovarian tumors was monitored by a non-invasive luminescent imaging system. Intra-peritoneal hyperthermia induced significant pro-inflammatory cytokines expression, and sustained the response of NK and DCs induced by α-GalCer treatment. The combination treatment enhanced the cytotoxic T lymphocyte (CTL) immune response in two mouse ovarian cancer models. This novel treatment modality by combination of hyperthermia and glycolipid provides a pronounced anti-tumor immune response and better survival. In conclusion, intra-peritoneal hyperthermia enhanced the pro-inflammatory cytokine secretion and phagocytic activity of DCs stimulated by α-GalCer. The subsequent CTL immune response induced by α-GalCer was further strengthened by combining with i.p. hyperthermia. Both innate and adaptive immunities were involved and resulted in a superior therapeutic effect in treating the ovarian cancer.

Formulation and evaluation of oral microparticulate ovarian cancer vaccines

Ovarian cancer is the fifth most leading cause of cancer related deaths in women in the US. Customized immunotherapeutic strategies may serve as an alternative method to control the recurrence or progression of ovarian cancer and to avoid severe adverse effects of chemotherapy. In this study, a microparticulate vaccine using whole cell lysate of a murine ovarian cancer cell line, ID8 was prepared with the use of a spray dryer. These particles were designed for oral delivery using enteric polymers such as methacrylic copolymer, Eudragit® FS30D and hydroxyl propyl methyl cellulose acetate succinate. These particles were targeted for uptake via microfold cell (M-cell) in Peyer's patches of small intestine using M-cell targeting ligand, Aleuria aurantia lectin. The interleukins (ILs) such as IL-2 and IL-12 were added to the vaccine formulation to further enhance the immune response. The particles obtained were of 1.58±0.62μm size with a charge of 12.48±2.32mV. The vaccine efficacy was evaluated by administering the particles via oral route to C57BL/6 female mice. At the end of vaccination, mice were challenged with live tumor cells. Vaccinated mice showed significant (around six-fold) retardation of tumor volume in comparison to non-vaccinated animals for 3 weeks after the tumor challenge (p<0.001). The serum IgG antibody levels were found to be elevated in case of vaccinated animals in comparison to non-vaccinated group (p<0.05). Analysis of IgG1 titers (indicative of Th2 response) and IgG2a titers (indicative of Th1 response) showed a mixed Th1 and Th2 immune response in case vaccine alone and Th2 response in case of vaccine with interleukins group. Moreover, CD8+ T-cell, CD4+ T-cell and B-cell populations in different lymphatic organs were elevated in case of vaccinated mice. Thus, whole cell lysate vaccine microparticles formulated by spray drying could trigger humoral as well as cellular immune response when administered orally. Such vaccine could potentially be an effective treatment for patients with residual tumor or high tumor-relapse probability.

Time-dependent cytotoxic drugs selectively cooperate with IL-18 for cancer chemo-immunotherapy

BackgroundTime-dependent chemotherapeutic agents can selectively target tumor cells in susceptible phases of the cell cycle however a fraction of tumor cells in non-vulnerable cell cycle phases remain drug-resistant. Immunotherapy represents a promising approach to overcome the limitation of phase-specific drugs and improve their clinical efficacy. Here, we investigated the potential use of anticancer chemotherapeutic drugs in combination with IL-18, a cytokine with strong immunostimulatory properties.MethodsFour chemotherapeutic drugs commonly used in ovarian cancer were first tested for the ability to increase the immunogenicity and killing of the murine ovarian cancer cell line ID8 in vitro. Chemotherapeutric agents with measured time-dependent immune-enhancing effects were then tested for antitumor effectiveness in vivo in combination with IL-18 immunotherapy using the ID8-Vegf ovarian cancer model.ResultsPaclitaxel or topotecan exposure alone mediated incomplete, time-dependent killing against the murine ovarian cancer cell line ID8 in vitro, whereas carboplatin or gemcitabine mediated comprehensive, dose-dependent killing. In the plateau phase of the time-dependent killing by topotecan or paclitaxel, drug-resistant ID8 cells were more immunogenic with elevated expression of MHC-I and Fas, and increased sensitivity to CTL and Fas agonistic antibody in vitro. Moreover, the antitumor effectiveness of time-dependent agents in vivo was significantly improved with the addition of IL-18 through a T cell-dependent mechanism, while the effectiveness of drugs without significant phase specificity were not.ConclusionsTumor immunotherapy with IL-18 can significantly augment the killing fraction of phase-specific chemotherapeutic drugs and provide survival benefit. The safety profile of IL-18 and its positive interactions with select anticancer chemotherapeutic agents strongly supports the clinical investigation of this combinatorial approach.

Abstract 551: A potent and selective cFMS inhibitor regulates the tumor macrophage microenvironment leading to tumor growth inhibition

Abstract Increasing evidence suggests that interactions between tumor cells, stromal cells, macrophages and the extracellular matrix are pivotal to the processes of tumorigenesis, metastasis, and neovascularization. Macrophages within the tumor microenvironment are thought to facilitate cancer progression, making them intriguing targets for therapy. Colony stimulating factor 1 (CSF-1) and its receptor, cFMS, play a central role in the development of mononuclear phagocytes, recruitment of macrophages to tumors, and differentiation and function of osteoclasts. We have developed an orally active, selective small-molecule cFMS inhibitor for cFMS. This molecule inhibits cFMS cellular activity (IC50 = 9 nM) in vitro and inhibits cFMS phosphorylation in a transfected cell line grown in nude mice (ED50 = 3 mg/kg). Our compound also inhibits CSF-1-mediated osteoclast differentiation and function (IC50 values of = 4 nM and 58 nM, respectively). To further explore the potential of our selective inhibitor for the treatment of cancer, we evaluated anti-tumor activity in several preclinical models. We first explored the effect on the murine ovarian cancer cell line, ID8. ID8 cells injected intraperitoneally into nude mice form multiple peritoneal tumor deposits and abundant ascites. Macrophage infiltration in the ID8 ascites was markedly lowered in mice treated with a cFMS inhibitor. Using MCF-7, a human breast adenocarcinoma cell line that has been shown to produce M-CSF, a daily oral dose with 100 mg/kg of our inhibitor for 21 days significantly reduced tumor growth and was accompanied by a marked reduction in tumor-associated macrophages. These findings support the potential of a selective inhibitor of cFMS to favorably impact human cancers by modulating tumor-associated macrophage functions. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 551. doi:10.1158/1538-7445.AM2011-551

Targeted Removal of Migratory Tumor Cells by Functionalized Magnetic Nanoparticles Impedes Metastasis and Tumor Progression

To slow tumor progression by reducing migratory tumor cell burden using magnetic nanoparticles (MNPs) functionalized with ligands selective for malignant cell surface receptors. Three groups of female C57BL/6 mice (control group I, control group II and experimental group) were intraperitoneally injected with a murine ovarian cancer cell line (ID8[VEGF160(+)/eGFP(+)]). Control group I received no intervention. MNPs were functionalized with ephrin-A1 mimetic peptides selective for the EphA2 receptor that is highly expressed by several cancers. Peritoneal fluids were removed by paracentesis from the experimental group and mixed with the functionalized MNPs. Magnetic filtration was used to remove particle/malignant cell conjugates and filtered peritoneal fluids were re-introduced intraperitoneally. Control group II received the same treatment as the experimental group without MNPs. Experimental group tumor progression was 10.77-times slower than that of control group I. Reduction of malignant cell titer significantly prolonged time to end point in a metastatic ovarian cancer model.