Animal Models Of Ovarian Cancer Research Articles

Silencing of FAM111B inhibits tumor growth and promotes apoptosis by decreasing AKT activity in ovarian cancer.

Ovarian cancer is the most lethal gynecological tumor in women worldwide. FAM111B (family with sequence similarity 111 member B) is an oncoprotein associated with multiple cancers, but its biological functions in ovarian cancer remain elusive. In this study, FAM111B was overexpressed in ovarian cancer tissues and cell lines. Functional studies in vitro revealed that silencing of FAM111B inhibited ovarian cancer cell proliferation, invasion, and migration, as well as increased cell apoptosis. Furthermore, FAM111B silencing arrested the ovarian cancer cell cycle at the G1/S phase. Furthermore, western blot assays demonstrated that silencing of FAM111B resulted in downregulation of phospho-AKT (p-AKT) protein expression, as well as upregulation of p53 and caspase-1 protein expression. The xenograft animal model of ovarian cancer demonstrated that FAM111B silencing inhibited tumor growth, enhanced cell apoptosis, and inhibited Ki-67 and proliferating cell nuclear antigen (PCNA) protein expression in vivo. Conversely, the overexpression of FAM111B exhibited opposite effects on the ovarian cancer xenograft. It was previously established that inactivating AKT inhibited ovarian cancer progression. This study found that silencing of FAM111B inhibits tumor growth and promotes apoptosis by decreasing AKT activity in ovarian cancer. Caspase-1 and p53 signaling also influenced the function of FAM111B in SKOV3 cells. Collectively, our results demonstrate that silencing of FAM111B is a potential therapeutic strategy against ovarian cancer.

Protein kinase RNA-activated controls mitotic progression and determines paclitaxel chemosensitivity through B-cell lymphoma 2 in ovarian cancer.

Anti-tubulin agents, such as paclitaxel, have been used extensively for treatment of several types of cancer, including ovarian, lung, breast, and pancreatic cancers. Despite their wide use in cancer treatment, however, patient response is highly variable and drug resistance remains a major clinical issue. Protein kinase RNA-activated (PKR) plays a critical role in immune response to viral infection. We identified PKR as a phospho-protein in response to anti-tubulin agents and this phosphorylation occurs independent of its own kinase activity. PKR is phosphorylated by cyclin-dependent kinase 1 (CDK1) during anti-tubulin treatment and unperturbed mitosis and that PKR regulates mitotic progression in a phosphorylation-dependent manner. Furthermore, inactivation of PKR confers resistance to paclitaxel in ovarian and breast cancer cells in vitro and in vivo. PKR expression levels and activity are decreased in chemotherapeutic recurrent ovarian cancer patients. Mechanistically, our findings suggest that PKR controls paclitaxel chemosensitivity through repressing Bcl2 expression. Pharmacological inhibition of Bcl2 with FDA-approved agent venetoclax overcomes paclitaxel resistance in preclinical animal models of ovarian cancer. Our results suggest that PKR is a critical determinant of paclitaxel cytotoxicity and that PKR-Bcl2 axis as a potential therapeutic target for the treatment of recurrent drug-resistant ovarian tumors.

Oleuropein reduces cisplatin resistance in ovarian cancer by targeting apoptotic pathway regulators

AimsDespite many attempts to treat ovarian cancer, 13,940 individuals perish annually due to this disease worldwide. Chemotherapy is the main approach to ovarian cancer treatment, but the development of drug resistance is a major obstacle to the successful treatment. Oleuropein is a phenolic ingredient with anticancer characteristics. This study was aimed at investigating the effect of oleuropein on cell viability, cisplatin resistance, and apoptosis, as well as the expression levels of miR-34a, miR-125b, miR16, miR-21, and some of their potential target genes in ovarian cancer cells. Main methodsA2780S and A2780/CP cell lines were exposed to different concentrations of oleuropein alone or in combination with cisplatin for 48 h and 72 h. After that, the cell viability and apoptosis were evaluated using MTT assay and flow cytometry, respectively. Bioinformatics analyses were conducted using STRING database and Cytoscape software. The effect of oleuropein and/or cisplatin on the expression of miRNAs and target genes was assessed via Real-time PCR. Key findingsUpon treatment with oleuropein, the expression of P21, P53, and TNFRSF10B increased while that of Bcl-2 and Mcl1 decreased. Moreover, this is the 1st report of a significant decrease in the expression of miR-21 and increase in the expression of miR-34a, miR-125b, and miR16 by oleuropein and/or cisplatin in ovarian cancer cells. SignificanceAltogether, these data revealed that oleuropein regulated the expression of the above-mentioned miRNAs in ovarian cancer cells, which potentially resulted in apoptosis induction, cell proliferation inhibition, and cisplatin resistance decline in ovarian cancer cells. To confirm the results of this study, it is suggested that similar experiments be performed in animal models of ovarian cancer.

Abstract B35: Dietary flaxseed supplementation in ovarian cancer: Elucidating the molecular actions of its biologically derived active compounds

Abstract The goal of our study is to elucidate the anti-ovarian cancer molecular mechanisms promoted by a flaxseed-supplemented diet in the laying hen. A flaxseed-supplemented diet generates a myriad of biologically active compounds that work synergistically to attack ovarian tumors. Our laboratory has demonstrated that flaxseed diet reduces the occurrence and severity of ovarian cancer in laying hen—the only spontaneous animal model for ovarian cancer. Flax diet in chicken induces the CYP1A1 pathway of estrogen metabolism increasing production of 2-hydroxy and 2-methoxy metabolites. 2-methoxyestradiol (2ME) is produced by the Catechol-O-Methyl transferase (COMT) enzyme from 2-hydroxyestradiol—a pathway that reduces estrogen toxicity, which is protective against ovarian cancer. Flaxseed is also a rich source of omega-3 fatty acids, mostly a-linoleic acid (ALA), which is converted into docosahexaenoic acid (DHA) in the gut. We have recently shown that flaxseed diet induces apoptosis and inhibits angiogenesis in the chicken ovarian tumors. 2ME promotes apoptosis and inhibits angiogenesis via activation of p38-MAPK; DHA has potent antiangiogenic and anti-inflammatory actions, however not dependent on the p38-MAPK pathway. To further investigate the molecular mechanisms of the antiangiogenic actions of flax diet, a qRT-PCR array analyzing 84 key genes involved in angiogenesis was performed. Nine key genes were significantly downregulated with flax diet. These genes are involved in hypoxia-induced endothelial cell migration, proliferation, differentiation, and lymphangiogenesis. Using human ovarian cancer cells, DNA damage was studied by TUNEL staining; DNA content and cell cycle progression were studied by PI staining and flow cytometry; apoptosis was measured by cleavage of caspase-3 by Western blot. 2ME treatment induced phosphorylation at ser139 of histone H2A (gH2Ax), a known marker for dsDNA breaks, along with phosphorylation at ser10 of histone H3 (pHH3) and ser14 of histone H2B (pHH2B). 2ME is known to bind at/near the colchicine binding site of the growing microtubules and therefore arresting cells at G2/M phase. 2ME effects were equivalent in ERa positive and negative human ovarian cancer cells. Also, the selective GPR30 agonist and antagonist, G1 and G15, did not modulate the effects of 2ME. Therefore, the anticancer actions of 2ME are not dependent on or mediated through the estrogen receptors. (NIH RO1AT005295) Citation Format: Purab Pal, Karen Hales, Dale Buchanan Hales. Dietary flaxseed supplementation in ovarian cancer: Elucidating the molecular actions of its biologically derived active compounds [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr B35.

Fluorescence and Multiphoton Imaging for Tissue Characterization of a Model of Postmenopausal Ovarian Cancer.

To determine the efficacy of targeted fluorescent biomarkers and multiphoton imaging to characterize early changes in ovarian tissue with the onset of cancer. A transgenic TgMISIIR-TAg mouse was used as an animal model for ovarian cancer. Mice were injected with fluorescent dyes to bind to the folate receptor α, matrix metalloproteinases, and integrins. Half of the mice were treated with 4-vinylcyclohexene diepoxide (VCD) to simulate menopause. Widefield fluorescence imaging (WFI) and multiphoton imaging of the ovaries and oviducts were conducted at 4 and 8 weeks of age. The fluorescence signal magnitude was quantified, and texture features were derived from multiphoton imaging. Linear discriminant analysis was then used to classify mouse groups. Imaging features from both fluorescence imaging and multiphoton imaging show significant changes (P < 0.01) with age, VCD treatment, and genotype. The classification model is able to classify different groups to accuracies of 75.53%, 69.53%, and 86.76%, for age, VCD treatment, and genotype, respectively. Building a classification model using features from multiple modalities shows marked improvement over individual modalities. This study demonstrates that using WFI with targeted biomarkers, and multiphoton imaging with endogenous contrast shows promise for detecting early changes in ovarian tissue with the onset of cancer. The results indicate that multimodal imaging can provide higher sensitivity for classifying tissue types than using single modalities alone. Lasers Surg. Med. © 2020 Wiley Periodicals, Inc.

Abstract B20: p53 regulation of repetitive elements and the interferon response in cancer

Abstract Here we characterize the effects of p53 status on the immune microenvironment of tumors. Specifically, we focus on the immune response induced by treatment with epigenetic modulators like 5-azacytidine (Aza), a DNA methyltransferase inhibitor (DNMTi), and whether this differs in tumors with and without functional p53. We and others have previously shown that cancer cells elicit an immune response when treated with epigenetic modulators such as DNMTis. These drugs inhibit methylation-induced gene silencing and cause re-expression of repetitive elements. Furthermore, they trigger interferon signaling in tumors by upregulation of double-stranded RNA (dsRNA) including DNA methylated endogenous retroviruses (ERVs), remains of exogenous retroviruses that integrated into the germline millions of years ago. The tumor suppressor protein p53, which is mutated in over half of all cancers, acts as a transcriptional repressor of ERVs. Little is known about the interaction between ERVs and p53 in a pathophysiologic model such as cancer. We hypothesize that p53 mutations influence the epigenetic regulation and ERV-induced immune signaling in cancer cells treated with Aza. We injected mouse ovarian cancer cells with p53 wild-type or null status into a syngeneic animal model for ovarian cancer and treated these mice with vehicle or Aza, an FDA-approved epigenetic modulator for myelodysplastic syndrome. We report that after 15 weeks, mice injected with p53 null cells present with a significantly higher tumor burden reflected in occurrence and volume of abdominal ascites fluid, weight gain over time, and shorter survival compared to mice injected with p53 wild-type cells. Further, Aza treatment compared to mock has a significant positive effect on tumor burden and survival but exclusively in mice with p53 null cells. No significant differences between treatments in the groups containing p53 wild-type cells were observed, indicating that the presence of p53 in these tumor cells likely abrogates the immunologic antitumor effects of Aza. This makes sense as p53 is a major transcriptional regulator of repetitive elements such as ERVs, which are upregulated after Aza treatment in this tumor model. We are currently characterizing differences in immune regulation of these treatment groups, in particular, infiltrating lymphocytes and Type I interferon signaling, which is crucial for the antitumor effect of Aza. We have studied how functional or lack of p53 contributes to the epigenetic regulation of ERVs and their potential to sensitize patients to immune therapy. We are now creating isogenic ovarian cancer cells containing wild-type or null as well as p53 point mutations, which occur in the majority of cancers. In doing so, we will gain novel information about the effects of mutant p53 on the ERV-induced immune response in tumor cells. Considering the vast amount of cancers harboring p53 mutations, assessing the p53 mutational status in cancers could become a useful biomarker for epigenetic therapies activating ERVs. Citation Format: Elisa Arthofer, Noor Diab, Katherine Bakshian Chiappinelli. p53 regulation of repetitive elements and the interferon response in cancer [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr B20.

CD105 Is Expressed in Ovarian Cancer Precursor Lesions and Is Required for Metastasis to the Ovary.

Most high-grade serous ovarian cancers (HGSCs) initiate from the fallopian tube epithelium and then metastasize to the ovary and throughout the abdomen. Genomic analyses suggest that most HGSCs seed the ovary prior to abdominal dissemination. Similarly, animal models support a critical role for the ovary in driving abdominal dissemination. Thus, HGSC cell recruitment to the ovary appears to be a critical component of HGSC cell metastasis. We sought to identify factors driving HGSC recruitment to the ovary. We identified CD105 (endoglin, or ENG, a TGF-β receptor family member) as a mediator of HGSC cell ovarian recruitment. We found that CD105 was expressed on both serous tubal intraepithelial carcinoma (STIC) cells (STICs-HGSC precursors in the fallopian tube epithelium) and HGSC cells. Using data from The Cancer Genome Atlas (TCGA) and the Cancer Cell Line Encyclopedia (CCLE), we showed that high CD105 expression by HGSC cells correlated with a metastatic signature. Furthermore, intravenous injection of CD105(+) HGSC tumor cells, but not CD105(−), resulted in ovarian-specific metastasis and abdominal dissemination of disease. CD105 knockdown or blockade with a clinically relevant CD105-neutralizing mAb (TRC105), inhibited HGSC metastasis, reduced ascites, and impeded growth of abdominal tumor nodules, thereby improving overall survival in animal models of ovarian cancer. CD105 knockdown was associated with a reduction in TGF-β signaling. Together, our data support CD105 as a critical mediator of ovarian cancer spread to the ovary and implicate it as a potential therapeutic target.

Ovarian Cancer Animal Models for Preclinical Studies and Development of Ovarian Cancer Drugs

Treatment for ovarian carcinoma is still far from optimal, animal models are still needed to study human epithelial ovarian cancer. Animal models of ovarian cancer are very important for understanding the pathogenesis of the disease and for testing new treatment strategies. Ovarian carcinogenesis models in mice have been modified and repaired to produce preneoplastic lesions and neoplastic ovaries that are pathogens resembling human ovarian cancer. Although spontaneous ovarian tumors in mice have been reported, some of the shortcomings of existing studies preclude their use as animal models of ovarian cancer. Because of this, many efforts have been made to develop animal models that are relevant for ovarian cancer. Experimental animal models are developed accurately to represent cellular and molecular changes associated with the initiation and development of human ovarian cancer. Accurate experimental models have significant potential in facilitating the development of better methods for early detection and treatment of ovarian cancer. Several animal models of ovarian cancer have been reported, including manipulation of various reproductive factors or exposure to carcinogens. The latest advance in ovarian cancer modeling is using genetically engineered mice.

Posttraumatic Stress Disorder Is Associated with Increased Risk of Ovarian Cancer: A Prospective and Retrospective Longitudinal Cohort Study.

Ovarian cancer is the deadliest gynecologic cancer. Chronic stress accelerates tumor growth in animal models of ovarian cancer. We therefore postulated that posttraumatic stress disorder (PTSD) may be associated with increased risk of ovarian cancer. We used data from the Nurses' Health Study II, a longitudinal cohort study with 26 years of follow-up, conducted from 1989 to 2015 with 54,710 subjects. Lifetime PTSD symptoms were measured in 2008. Self-reported ovarian cancer was validated with medical records. Risk of ovarian cancer was estimated with Cox proportional hazards models and further adjusted for known ovarian cancer risk factors (e.g., hormonal factors) and health risk factors (e.g., smoking). Fully prospective secondary analyses examined incident ovarian cancer occurring after PTSD assessment in 2008. In addition, we examined associations by menopausal status. During follow-up, 110 ovarian cancers were identified. Women with high PTSD symptoms had 2-fold greater risk of ovarian cancer versus women with no trauma exposure [age-adjusted HR = 2.10; 95% confidence interval (CI), 1.12-3.95]. Adjustment for health and ovarian cancer risk factors moderately attenuated this association (HR = 1.86; 95% CI, 0.98-3.51). Associations were similar or moderately stronger in fully prospective analyses (age-adjusted HR = 2.38; 95% CI, 0.98-5.76, N cases = 50) and in premenopausal women (HR = 3.42; 95% CI, 1.08-10.85). In conclusion, we show that PTSD symptoms are associated with increased risk of ovarian cancer. Better understanding of the underlying molecular mechanisms could lead to interventions that reduce ovarian cancer risk in women with PTSD and other stress-related mental disorders. SIGNIFICANCE: PTSD is associated with ovarian cancer risk, particularly in premenopausal women. Understanding the underlying molecular mechanisms will aid in formulating ways to reduce ovarian cancer risk associated with chronic stress.

SMAD3 inducing the transcription of STYK1 to promote the EMT process and improve the tolerance of ovarian carcinoma cells to paclitaxel.

To figure out the relationship between SMAD3 and serine-threonine tyrosine kinase (STYK1) in ovarian carcinoma cell's paclitaxel resistance. The quantitative reverse transcription-polymerase chain reactpostion and Western blot analysis were used to analyze RNA and protein content of SMAD3 and STYK1, respectively. The chromatin immunoprecipitation assay was used to confirm the binding site of SMAD3 to the STYK1 promoter region. Transwell assay was used to detect cell invasion and migration, and Western Blot was used to detect the marker proteins (vimentin and E-cadherin) of epithelial-mesenchymal transition (EMT) process. MTT and apoptosis assay were used to, respectively, measure cell vitality and apoptosis. In vivo experiments, rats were subcutaneously implanted with A2780 cells to establish an animal model of ovarian cancer and the survival curve was drawn. Upregulating SMAD3 induced the expression of STYK1 in ovarian cancer cell lines. STYK1 is a direct transcriptional target of SMAD3. Upregulating STYK1 improved the paclitaxel resistance of ovarian carcinoma cells. Upregulating STYK1 promoted cell invasion, migration, and the EMT process, and SMAD3 had the same effect with STYK1 on cell invasion, cell migration, and the EMT process. The animal assay showed that downregulating STYK1 inhibited the EMT process and the paclitaxel resistance, further promoting the treatment of cervical cancer. SMAD3 combined with the promoter region of STYK1 to promote the transcription process of STYK1, thereby promoting the EMT process and paclitaxel resistance of ovarian cancer cells.

Exosomal miRNA confers chemo resistance via targeting Cav1/p-gp/M2-type macrophage axis in ovarian cancer.

BackgroundCirculating miRNAs are known to play important roles in intercellular communication. However, the effects of exosomal miRNAs on cells are not fully understood.MethodsTo investigate the role of exosomal miR-1246 in ovarian cancer (OC) microenvironment, we performed RPPA as well as many other in vitro functional assays in ovarian cancer cells (sensitive; HeyA8, Skov3ip1, A2780 and chemoresistant; HeyA8-MDR, Skov3-TR, A2780-CP20). Therapeutic effect of miR-1246 inhibitor treatment was tested in OC animal model. We showed the effect of OC exosomal miR-1246 uptake on macrophages by co-culture experiments.FindingsSubstantial expression of oncogenic miR-1246 OC exosomes was found. We showed that Cav1 gene, which is the direct target of miR-1246, is involved in the process of exosomal transfer. A significantly worse overall prognosis were found for OC patients with high miR-1246 and low Cav1 expression based on TCGA data. miR-1246 expression were significantly higher in paclitaxel-resistant OC exosomes than in their sensitive counterparts. Overexpression of Cav1 and anti-miR-1246 treatment significantly sensitized OC cells to paclitaxel. We showed that Cav1 and multi drug resistance (MDR) gene is involved in the process of exosomal transfer. Our proteomic approach also revealed that miR-1246 inhibits Cav1 and acts through PDGFβ receptor at the recipient cells to inhibit cell proliferation. miR-1246 inhibitor treatment in combination with chemotherapy led to reduced tumor burden in vivo. Finally, we demonstrated that when OC cells are co-cultured with macrophages, they are capable of transferring their oncogenic miR-1246 to M2-type macrophages, but not M0-type macrophages.InterpretationOur results suggest that cancer exosomes may contribute to oncogenesis by manipulating neighboring infiltrating immune cells. This study provide a new mechanistic therapeutic approach to overcome chemoresistance and tumor progression through exosomal miR-1246 in OC patients.

Ovarian Cancer Immunotherapy: Preclinical Models and Emerging Therapeutics.

Immunotherapy has emerged as one of the most promising approaches for ovarian cancer treatment. The tumor microenvironment (TME) is a key factor to consider when stimulating antitumoral responses as it consists largely of tumor promoting immunosuppressive cell types that attenuate antitumor immunity. As our understanding of the determinants of the TME composition grows, we have begun to appreciate the need to address both inter- and intra-tumor heterogeneity, mutation/neoantigen burden, immune landscape, and stromal cell contributions. The majority of immunotherapy studies in ovarian cancer have been performed using the well-characterized murine ID8 ovarian carcinoma model. Numerous other animal models of ovarian cancer exist, but have been underutilized because of their narrow initial characterizations in this context. Here, we describe animal models that may be untapped resources for the immunotherapy field because of their shared genomic alterations and histopathology with human ovarian cancer. We also shed light on the strengths and limitations of these models, and the knowledge gaps that need to be addressed to enhance the utility of preclinical models for testing novel immunotherapeutic approaches.

Abstract 5142: Elevated glycolysis in pre-malignant ovarian cancer

Abstract Ovarian cancer is the fifth leading cause of cancer death in women and the most lethal gynecologic malignancy. High-grade serous ovarian carcinoma (HGSC) originates mainly from the fallopian tube epithelium, and is characterized by TP53 mutation identified in all HGSCs as well as the fallopian tubal precursor of serous tubal intraepithelial carcinomas (STICs). The loss of a functional TP53 is an early event in the malignant transformation of fallopian tube epithelium. We have established 4 primary cell cultures of normal fallopian tube epithelial (FTE) cells, and further generated immortalized FTE cells using SV40 large plus small T antigens (FTE-TAg) to disrupt TP53 function. This model mimics the primary lesions of ovarian cancer and is suitable to identify biomarkers and molecular targets of ovarian cancer. Therefore, we compared the secretomes of primary FTE cells with that of their parental isogenic pairs FTE-TAg cells using mass spectrometry analysis. We identified 813 proteins, 228 of which were differentially expressed. Ingenuity Pathway Analysis (IPA) core analysis revealed glycolysis as a major canonical pathway. Overexpression of key enzymes of glycolytic pathway was confirmed by IHC in human STIC lesions. Molecular mechanisms of glycolysis regulation in premalignant lesion of ovarian cancer were determined. Role of glycolysis in the establishment of premalignant ovarian cancer microenvironment (PME) was characterized. Prevention approaches targeting glycolysis were tested in transgenic animal model of ovarian cancer. Citation Format: Anna E. Lokshin, Mounia Alaoui El Azher, Liudmila Velikokhatnaya, Denise Prosser. Elevated glycolysis in pre-malignant ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5142.

Effect of lanthanum chloride on tumor growth and apoptosis in human ovarian cancer cells and xenograft animal models

Ovarian cancer is the leading cause of mortality resulting from gynecologic cancer. A common anti-ovarian tumor drug is cisplatin; however, repeated use of cisplatin causes severe resistance and leads to poor long-term survival rate in ovarian cancer patients. Recently, it was reported that lanthanum chloride (LaCl3) may inhibit tumor growth and induce apoptosis in certain cancer cells. In the present study, the effect of LaCl3 on ovarian cancer was determined in vivo and in vitro. A cisplatin-sensitive human ovarian cancer cell line, COC1, was used in the current study. A xenograft animal model of ovarian cancer was established injecting COC1 or cisplatin-resistant COC1 cells (COC1/DDP) cells into mice. A TUNEL assay was used to determine the apoptosis of the COC1 or COC1/DDP cells and a immunohistochemical assay was conducted to measure the expression of B-cell lymphoma-2, Ki67, breast cancer 1 (BRCA)1, BRCA2 and excision repair cross-complementation group 1 in COC1 or COC1/DDP cells. It was observed that LaCl3 promoted apoptosis in COC1 and COC1/DDP cells. In addition, LaCl3 plus cisplatin led to further increase in the expression levels of tumor suppressor genes and decrease in the expression of oncogenes. Furthermore, application of LaCl3 and cisplatin inhibited tumor growth in vivo in a xenograft animal model. These results indicated the synergistic role of LaCl3 on cisplatin-induced inhibition of cancer cell proliferation and tumor growth, providing a potential and effective candidate for the treatment of ovarian tumors.

The chicken animal model for ovarian cancer and for pharmacological and toxicological evaluation of NGcGM3 ganglioside based treatments

The chicken animal model for ovarian cancer and for pharmacological and toxicological evaluation of NGcGM3 ganglioside based treatments

The distribution of the apparent diffusion coefficient as an indicator of the response to chemotherapeutics in ovarian tumour xenografts

Diffusion-weighted magnetic resonance imaging (DW-MRI) was used to evaluate the effects of single-agent and combination treatment regimens in a spheroid-based animal model of ovarian cancer. Ovarian tumour xenografts grown in non-obese diabetic/severe-combined-immunodeficiency (NOD/SCID) mice were treated with carboplatin or paclitaxel, or combination carboplatin/paclitaxel chemotherapy regimens. After 4 weeks of treatment, tumours were extracted and underwent DW-MRI, mechanical testing, immunohistochemical and gene expression analyses. The distribution of the apparent diffusion coefficient (ADC) exhibited an upward shift as a result of each treatment regimen. The 99-th percentile of the ADC distribution (“maximum ADC”) exhibited a strong correlation with the tumour size (r2 = 0.90) and with the inverse of the elastic modulus (r2 = 0.96). Single-agent paclitaxel (n = 5) and combination carboplatin/paclitaxel (n = 2) treatment regimens were more effective in inducing changes in regions of higher cell density than single-agent carboplatin (n = 3) or the no-treatment control (n = 5). The maximum ADC was a good indicator of treatment-induced cell death and changes in the extracellular matrix (ECM). Comparative analysis of the tumours’ ADC distribution, mechanical properties and ECM constituents provides insights into the molecular and cellular response of the ovarian tumour xenografts to chemotherapy. Increased sample sizes are recommended for future studies. We propose experimental approaches to evaluation of the timeline of the tumour’s response to treatment.

Detection and Characterization by Immunohistochemistry of the NGcGM3 Ganglioside in the Chicken Animal Model of Ovarian Cancer

In spite of ovarian cancer mortality rates have tended to level off and decrease during the last years in several countries, the disease is still the gynecological cancer with the highest death rate. The current therapies for ovarian cancer include surgery and chemotherapy based on platinum and a taxane. Nevertheless, these therapies are only efficient at the first stages of the disease and the treatments are lack of specificity, further contributing to the high mortality rates of ovarian cancer. The adult laying hen is a very interesting model for studying the development of the epithelial ovarian cancer since hen develops intense ovulation, spontaneous ovarian cancers and metabolic progression similar to women. It is known that normal chicken cells and human cells have no metabolic pathway for NeuGc biosynthesis due to a partial deletion in the gene that encodes CMP-Neu5Ac hydroxylase. Gangliosides are interesting type of molecules, different from proteins that have been identified as tumor antigens. Mammalian cells have these types of glycosphingolipids on their plasmatic membranes. Due to gangliosides are over-expressed in many tumors compared with the corresponding normal tissues, they are considered as very attractive compounds for immunotherapy, attributing to them a very important role in the growth and metastatic tumor processes. The aim of this study is to elucidate by immunohistochemistry the existence of NeuGc-GM3 in hen ovarian cancers. Slides with normal and cancer ovarian tissues from 3.5 years old chickens were incubated with the very specific anti- NeuGcGM3 ganglioside 14F7 Mab for immunohistochemical studies. These studies showed that the 14F7 Mab immunorecognition was mainly evidenced in epithelial ovarian tumors and not in normal tissues. The presence of NeuGc-containing gangliosides in chicken and human epithelial ovarian cancers makes the chicken an interesting and relevant animal model for further experimental and translational investigations on ganglioside based immunotherapy.

VSV based virotherapy in ovarian cancer: the past, the present and …future?

The standard approach to treating patients with advanced epithelial ovarian cancer (EOC) after primary debulking surgery remains taxane and platinum-based chemotherapy. Despite treatment with this strategy, the vast majority of patients relapse and develop drug-resistant metastatic disease that may be driven by cancer stem cells (CSCs) or cancer initiating cells (CICs). Oncolytic viruses circumvent typical drug-resistance mechanisms, therefore they may provide a safe and effective alternative treatment for chemotherapy-resistant CSCs/CICs. Among oncolytic viruses vesicular stomatitis virus (VSV) has demonstrated oncolysis and preferential replication in cancer cells.In this review, we summarize the recent findings regarding existing knowledge on biology of the ovarian cancer and the role of ovarian CSCs (OCSCs) in tumor dissemination and chemoresistance. In addition we also present an overview of recent advances in ovarian cancer therapies with oncolytic viruses (OV). We focus particularly on key genetic or immune response pathways involved in tumorigenesis in ovarian cancer which facilitate oncolytic activity of vesicular stomatitis virus (VSV). We highlight the prospects of targeting OCSCs with VSV. The importance of testing an emerging ovarian cancer animal models and ovarian cancer cell culture conditions influencing oncolytic efficacy of VSV is also addressed.

Abstract 4196: Real-time single-walled nanotube (SWNT)-based imaging system improves tumor detection and survival in ovarian cancer animal model

Abstract Residual tumor detection in advanced stage ovarian cancer (OC) represents a critical challenge in the treatment of this disease. Optimal abdominal cytoreduction to reduce tumor to no evidence of macroscopic disease is the main endpoint of tumor debulking surgery, with demonstrated survival advantages, but the current clinically available imaging modalities have shown low tumor detection sensitivity of tumors smaller than 10 mm diameter. Instead, targeted molecule-based imaging systems offer higher detection rate and are likely to extend the aim of complete resection to the microscopic scale. We applied a custom designed imaging system to a preclinical ovarian cancer tumor model and observed higher microscopic tumor detection accuracy and survival advantage compared to non-image guided debulking surgery. A two component imaging system was developed. The contrast agent is an intra-peritoneal injectable nanomolecular probe, composed of a single walled carbon nanotube (SWNT) coupled with an engineered M13-bacteriophage carrying a modified peptide targeting secreted protein, acidic and rich in cysteine (SPARC), extracellular protein overexpressed in OC. The imaging device system is capable of detecting SWNT inherent fluorescence in near-infrared second window (NIR2) and of displaying real-time images to guide the intraoperative tumor debulking. In an orthotopic ovarian cancer animal model, the imaging system detected microscopic tumors in the millimeter and sub-millimeter scale resolution with a mean tumor diameter of 2.1 vs 3.6 mm (p&amp;lt; 0.01) compared to eye detected tumors. The imaging system demonstrated sensitivity of 97.2% and specificity of 69.7%, and a Receiver Operator Area under the Curve of 0.85 + 0.05. In a survival surgery animal model, the imaging guided resection surgery compared to non guided surgery showed a survival advantage for the experimental arm, with median survival time of 41.0 days vs 28.5 days, respectively (HR 0.22, 95% CI of ratio 0.04 to 1.08 Log Rank test: p: 0.063). The accuracy of the imaging system and its survival advantage are promising. The survival outcome improvement in this preclinical model supports the translation to first-in-human investigation. Moreover, the imaging system accuracy suggests further exploitation in targeted delivery therapies. Citation Format: Lorenzo Ceppi, YoungJeong Na, Neelkanth M. Bardhan, Andrew Siegel, Nandini Rajan, Angela M. Belcher, Michael J. Birrer. Real-time single-walled nanotube (SWNT)-based imaging system improves tumor detection and survival in ovarian cancer animal model. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4196.

Abstract A62: TRX-1 targets chemoresistant tumor-initiating cells and prolongs survival in a recurrent ovarian cancer animal model.

Abstract Background: Ovarian cancer is the leading cause of mortality from gynecologic cancers due to the high incidence of chemoresistance and disease recurrence. Disease recurrence is thought to occur due to the presence of residual disease following first-line standard of care (i.e. optimal debulking and chemotherapy). Residual disease post chemotherapy is composed of a unique population of chemoresistant cancer cells with stemness properties and a high capacity for tumor repair. Currently, there are no available options that can target these cells. The objective of this study was to develop a new therapeutic modality that will target chemoresistant ovarian cancer stem cells (OCSC) and consequently prevent recurrence and improve survival. To achieve this objective we developed a library of super-benzopyran (SBP) analogues and identified TRX-1 as the most potent analogue able to induce OCSC cell death in a short period of time. Moreover, in contrast to Cisplatin and Paclitaxel, TRX-1 is able to induce a persistent growth inhibitory effect both in vitro and in vivo thus improving overall survival in a mouse model of recurrent ovarian cancer. Materials and methods: A panel of SBP analogues were generated and activity was determined by testing against pure clones of CD44+/MyD88+ OCSC. In vitro efficacy was assessed using the IncucyteTM kinetic imaging platform complemented by CelltoxTM dye labeling. In vivo efficacy was tested using an intra-peritoneal (i.p.) a mouse model of recurrent ovarian cancer1. Results: TRX-1 was the most potent analogue identified and is able to induce cell death in all OCSC clones tested (IC50 of 136 nM). We observed that 2h in vitro exposure to 2μM TRX-1 was sufficient to induce a sustained growth inhibitory effect in OCSC, hence the cells were not able to recover growth potential even after removal of the drug. In contrast, OCSC exposed for up to 24h with the same dose of Cisplatin or Paclitaxel were able to recover. In vivo, animals bearing residual tumors after Paclitaxel treatment demonstrated tumor progression when further maintained with vehicle or Paclitaxel indicating Paclitaxel resistance. In contrast, maintenance with TRX-1 was able to effectively decrease tumor burden (p = 0.02) and prevent recurrence. In addition, combination treatment with TRX-1 and Cisplatin was able to significantly improve survival (p&amp;lt;0.001) compared to Cisplatin alone. Conclusion: We describe the in vitro and in vivo anti-tumoral effect of a novel compound, TRX-1, which exhibits significant efficacy against chemoresistant OCSC and is able to prevent recurrence in a chemoresistant in vivo model. Recurrence characterized by chemoresistance is the main cause of mortality in ovarian cancer patients. Previous studies from our laboratory have shown that conventional chemotherapy is not effective against OCSC and cannot prevent recurrence. Our finding that TRX-1, by targeting OCSC can prevent recurrence in vivo as maintenance therapy or in combination with chemotherapy provides a new opportunity for developing new therapeutic strategies that can improve survival in ovarian cancer patients. Citation Format: Ayesha Alvero, Eydis Lima, Mary Pitruzzello, Yang Yang-Hartwich, David Brown, Andrew Heaton, Gil Mor. TRX-1 targets chemoresistant tumor-initiating cells and prolongs survival in a recurrent ovarian cancer animal model. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: Exploiting Vulnerabilities; Oct 17-20, 2015; Orlando, FL. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(2 Suppl):Abstract nr A62.