bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract A41: The heat shock transcription factor HSF1 induces ovarian cancer epithelial-mesenchymal transition in a 3-D spheroid growth model.
Authors: Paullin Trillitye , Powell Chase , Christopher Menzie , Hill Robert , Martyniuk Christopher , Westerheide Sandy
Published: May 2016

Ovarian cancer is the most lethal gynecological cancer, with over 200,000 women diagnosed each year and over half of those cases leading to death. These poor statistics are related to a lack of early symptoms and inadequate screening techniques. This results in the cancer going undetected until later stages when the tumor has metastasized through a process that requires the epithelial to mesenchymal transition (EMT). In lieu of traditional monolayer cell culture, EMT and cancer progression in general is best characterized through the use of 3D spheroid models. Compared to other cancers, ovarian cancer has very limited treatment options to date, with cisplatin and paclitaxel being the most common and efficient. Recently, a significant increase in heat shock factor 1 (HSF1) expression has been found in highly malignant ovarian cancer. HSF1 is the regulator of the heat shock response (HSR) and promotes the transcription of heat shock proteins (HSPs). Previous studies have shown that HSF1-induced chaperone activity may act to stabilize multiple oncogenes within many different cancer types. This leads to cancer proliferation, reduced apoptosis, and metastasis. In this study, we examine gene expression changes through microarray analysis in spheroid versus monolayer ovarian cancer cells treated with TGFβ to induce EMT. Interestingly, EMT and stress response pathways, including the heat shock response, were all significantly affected by 3D growth. HSF1 knockdown was utilized in both 2D and 3D cultures to further study this response. HSF1 knockdown is shown to inhibit ovarian cancer progression in both monolayer and spheroid model cells. Moreover, HSF1 knockdown in spheroid cells has a significantly greater impact on EMT markers than it does in 2D cultures. This indicates HSF1 may be a utilized as a target for chemotherapeutics in ovarian cancer patients and could potentially have implications in other such hormonal cancers.

Citation Format: Trillitye Paullin, Chase Powell, Menzie Christopher, Robert Hill, Christopher Martyniuk, Sandy Westerheide. The heat shock transcription factor HSF1 induces ovarian cancer epithelial-mesenchymal transition in a 3-D spheroid growth 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 A41.
Abstract B17: Type 2 diabetes, metformin, and ovarian cancer survival: An analysis of tumor registry and electronic medical record data.
Authors: Keene Spencer , Stansel Samantha P. , Clayton Leshaun , Jiang Min , Aldrich Melinda , Xu Hua , Warner Jeremy , Denny Joshua , Khabele Dineo , Beeghly-Fadiel Alicia
Published: May 2016

Background: Type 2 Diabetes Mellitus (T2D) is associated with increased cancer risk and higher cancer mortality. Metformin, a common T2D treatment, is associated with improved survival for several cancers. With a five year survival of 42%, repurposing metformin to improve ovarian cancer prognosis is attractive. However, only a few studies to date have evaluated associations between T2D, metformin use, and ovarian cancer survival.

Methods: We evaluated tumor registry confirmed ovarian and fallopian tube cancer cases from the Vanderbilt University Medical Center. Metformin use was determined from electronic medical records (EMR) using MedEx. For validation, natural language processing EMR review was conducted for 50 subjects. Cox proportional hazards regression was used to evaluate associations with overall survival and calculate Hazard Ratios (HR) and corresponding 95% Confidence Intervals (CI); models included adjustment for age, stage, histologic subtype, and body-mass index (BMI).

Results: Tumor registry data and EMR was available for 372 invasive epithelial ovarian cancer cases. Forty (10.8%) had T2D, and 20 had metformin use (5.4%). MedEx and EMR reviewed metformin use was highly concordant (Kappa=0.96). Associations with overall survival were suggestive but non-significant for T2D (HR: 0.80, 95% CI: 0.51-1.25) and metformin use, either among only T2D cases (HR: 0.73, 95% CI: 0.29-1.84) or among all ovarian cancer cases (HR: 0.61, 95% CI: 0.31-1.21). Two or more years of metformin use was significantly associated with better survival compared to cases without metformin use (HR: 0.28, 95% CI: 0.09-0.89). Exploratory analyses suggested better survival among serous cases and worse survival among non-serous cases for both T2D and metformin, but associations were not significant. Analyses to address survival time bias yielded results comparable to our primary findings.

Conclusions: Ovarian cancer cases with metformin use had marginally better overall survival. While not significant, these associations indicate that metformin may have utility repurposed as a treatment for ovarian cancer. Larger studies are needed to determine if associations differ by histology, and if metformin may be beneficial to all ovarian cancer subtypes.

Citation Format: Spencer Keene, Samantha P. Stansel, Leshaun Clayton, Min Jiang, Melinda Aldrich, Hua Xu, Jeremy Warner, Joshua Denny, Dineo Khabele, Alicia Beeghly-Fadiel. Type 2 diabetes, metformin, and ovarian cancer survival: An analysis of tumor registry and electronic medical record data. [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 B17.
Abstract B30: Dietary fat intake and ovarian cancer risk.
Authors: Rice Megan , Tworoger Shelley
Published: May 2016

Purpose: Prevention recommendations for ovarian cancer have been limited because few confirmed risk factors are modifiable. While dietary fat intake has been proposed as a potential risk factor, results have been inconsistent possibly due to limitations of when diet was assessed (e.g., baseline only). Therefore, in two large prospective cohort studies, we examined the association between ovarian cancer risk and dietary fat intake, including cumulative average intake (long-term intake) as well as simple updated intake (recent intake).

Methods: We assessed recent (2-6 years prior to diagnosis) as well as long-term (cumulative average) dietary fat intake among 65,590 women in the Nurses' Health Study (NHS) and NHSII using food frequency questionnaires administered every 2-4 years beginning in 1984 and 1991 respectively. We examined intakes of total fat as well as specific types of fat (i.e., animal, vegetable, saturated, monounsaturated, polyunsaturated, and trans fat). We identified 536 cases of ovarian cancer throughout follow-up with information on recent diet. We used Cox proportional hazards regression to estimate the associations between dietary fat intake and risk of ovarian cancer.

Results: While recent total fat intake was not associated with ovarian cancer risk (RR comparing extreme quartiles= 1.05, 95%CI: 0.81-1.36), higher recent polyunsaturated fat intake was associated with a higher risk of ovarian cancer (RR comparing extreme quartiles=1.45, 95%CI: 1.08-1.94). However, there were no significant associations between cumulative average intakes of dietary fat and risk of ovarian cancer. For example, women in the highest quartile of cumulative average polyunsaturated fat intake had a non-significant 20% higher risk of ovarian cancer compared to those in the lowest quartile (95%CI: 0.88-1.62, p-trend=0.39).

Conclusion: While there were no significant associations between long-term dietary fat intake and risk of ovarian cancer in the NHS and NHSII, higher recent intake of polyunsaturated fat was associated with a higher risk of ovarian cancer. Future work will assess whether these associations vary histologic subtypes and by ER and PR expression in ovarian tumors.

Citation Format: Megan Rice, Shelley Tworoger. Dietary fat intake and ovarian cancer risk. [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 B30.
Abstract B43: Characterization of ovarian cancer cells as in vivo models for preclinical studies.
Authors: Hernandez Lidia , Kim Marianne K. , Lyle L Tiffany , Steeg Patricia S. , Annunziata Christina M.
Published: May 2016

Women are most often diagnosed with ovarian cancer in late stages of the disease, making this malignancy the most common cause of death from gynecological cancers in the United States. Identification of factors associated with disease subtypes and clinical outcome is critical to enable pathway-targeted therapeutic advances. As with other systems, the value of cell lines for in vitro and pre-clinical work lies in choosing groups of cell lines with similar characteristics. To date, selection of cell lines has been based on criteria such as patient history, histological subtype at diagnosis, mutation patterns, signaling patterns and tumorigenicity in mice. Most available ovarian cancer cell lines were generated decades ago and variable information exists as to these parameters. In recent years, several studies have reported comprehensive data gathered for the most commonly available ovarian cancer cell lines. While these reviews have established greater consensus regarding the molecular characteristics of these cell lines, data on in vivo tumorigenicity of these cell lines is still only sporadically available, making it difficult to translate in vitro work to xenograft models. We have studied the tumorigenicity of 16 commonly used ovarian cancer cell lines introduced through three distinct anatomical locations: subcutaneous, intraperitoneal, and ovary intrabursal injection. We also characterized these cell lines according to gene expression profiles and phospho-proteomics, in order to create an integrated panel of information by which to choose cells logically for specific research questions. Here we report a comprehensive analysis of in vivo growth patterns and histopathology, linked to molecular characteristics. This will provide a valuable resource to the ovarian cancer research community, and better guiding the choice of cell lines for in vitro studies that can be translated efficiently into xenograft testing.

Citation Format: Lidia Hernandez, Marianne K. Kim, L Tiffany Lyle, Patricia S. Steeg, Christina M. Annunziata. Characterization of ovarian cancer cells as in vivo models for preclinical studies. [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 B43.
Abstract B57: Sucrose nonfermenting 1-related kinase (SNRK) expression and function in ovarian cancer.
Authors: Bishop Erin A. , Cossette Stephanie M. , Ramchandran Ramani
Published: May 2016

Purpose of study: SNRK is a member of the sucrose nonfermenting (SNF)-related kinase family of serine/threonine kinases with sequence similarity to AMP-activated protein kinase (AMPK). AMPK proteins play a central role in cellular energy regulation. Active AMPK restricts cellular proliferation, growth, and metabolic substrate synthesis, and increases ATP-generating processes, such as glucose and fatty acid oxidation. SNKR has been previously shown to regulate metabolism and to suppress adipocyte inflammation via mTORC1, which is a pathway known to be aberrant in ovarian cancer. SNRK has also been shown to reduce colon cancer cell proliferation and stable knockdown of SNRK increases in vitro colon cancer cell tumorigenicity indicating that SNRK is a regulator of cell proliferation. The goal of this study is to describe the expression and function of SNRK in ovarian cancer and benign cell lines.

Experimental Procedures: The ovarian cancer cell line A2780 was used as well as the benign surface epithelial cell line, IOSE, for comparison. Quantitative PCR and western blot analysis were used to compare SNRK mRNA and protein expression between cell lines. SNRK was knocked down in each cell line using lentiviral transduction. Proliferation, migration, and invasion assays were performed to determine the effects of SNRK knockdown on tumorigenicity. Alterations in metabolism as a result of SNRK knockdown were assessed using the XF Extracellular Flux Analyzer (Seahorse Bioscience). Western blot analysis was used to determine changes in active phosphorylated AMPK (pAMPK) and mTOR protein expression.

Summary of data: IOSE and A2780 cells have similar levels of SNRK mRNA and protein expression. We observed increased proliferation, migration, and invasion in SNRK knockdown cells compared to controls with significant differences seen in the IOSE cells. A2780 and IOSE SNRK knockdown cells have decreased oxygen consumption rates and decreased spare respiratory capacity in the presence of fatty acids as a substrate compared to controls as well as decreased pAMPK and mTOR expression.

Conclusions: Our results show that decreased SNRK levels lead to increased tumorigenicity and impairment in fatty acid oxidation particularly in the benign IOSE cells. Along with these functional changes, a decrease in pAMPK expression is also seen. Our results suggest that SNRK plays a role in regulating growth and metabolism and that this regulation appears to be required in benign ovarian cells, while malignant cells may have the ability to control growth independent of SNRK.

Citation Format: Erin A. Bishop, Stephanie M. Cossette, Ramani Ramchandran. Sucrose nonfermenting 1-related kinase (SNRK) expression and function in ovarian cancer. [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 B57.
Abstract B59: The adhesion molecule L1: a new driver in ovarian cancer vasculature.
Authors: Angiolini Francesca , Magrini Elena , Fiore Pier Paolo Di , Cavallaro Ugo
Published: May 2016

Ovarian cancer (OC) represents an outstanding clinical challenge due to its high mortality rate, tumor relapse and chemoresistance. The identification of novel targets and strategies for the treatment of OC is clearly an unmet need in clinical oncology. In this context, drugs that interfere with tumor neovascularization have shown some promising results in recent clinical trials. However, anti-angiogenic therapies in most cases exhibit only transient and insufficient efficacy, resulting in tumor recurrence in patients after several months of treatment.

Thus, the definition of tumor vasculature biomarkers and of druggable molecular targets within cancer-associated angiogenesis will represent a breakthrough in this field.

Our laboratory has obtained compelling evidence that L1, an adhesion molecule that plays a key role in neural development, is aberrantly expressed in tumor vasculature. Furthermore, we have recently reported that vascular L1 plays a pivotal role in tumor angiogenesis and represents a viable target for therapies directed against cancer-associated vessels (Magrini et al., JCI, 2014). However, the functional role of L1 in endothelial cells and its contribution to tumor angiogenesis remain elusive.

Based on the observation that L1 is particularly abundant in OC vasculature as compared to normal tissue, we hypothesized that the loss of endothelial L1 would affect OC development. To test this hypothesis, we have established a syngeneic model of ovarian tumorigenesis in conditional knockout mice with the endothelium-specific ablation of L1. Interestingly, we observed that vascular L1 is causally involved in the peritoneal metastasis of OC, thus implicating L1 in tumor dissemination. In addition, the loss of endothelial L1 results in tumor vessel normalization, a process that has been proposed to enhance the efficacy of systemic chemotherapy.

Mechanistically, L1 emerged as a master regulator of the endothelial transcriptional and signaling activity, and was capable of orchestrating multiple functions of endothelial cells, thus accounting for the aberrant pathophysiology of cancer vessels. We are currently capitalizing on these observations to define the molecular mechanisms underlying such a pleiotropic role on the OC vasculature.

Our data may pave the way to innovative anti-angiogenic and/or vessel-normalizing therapies for the treatment of ovarian cancer.

Citation Format: Francesca Angiolini, Elena Magrini, Pier Paolo Di Fiore, Ugo Cavallaro. The adhesion molecule L1: a new driver in ovarian cancer vasculature. [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 B59.
Abstract B60: Identification of an ovarian tumor:stromal HH:BMP4 signaling loop critical to ovarian cancer growth and chemotherapy resistance.
Authors: Coffman Lan G. , Choi Yunjung , Mclean Karen , Magliano Marina Pasca di , Allen Benjamin , Buckanovich Ronald J.
Published: May 2016

The ovarian tumor microenvironment is critical to ovarian cancer growth, spread, and survival. We recently identified a novel host cell component of the tumor microenvironment, human ovarian carcinoma-associated mesenchymal stem cells (CA-MSCs). CA-MSCs are of particular interest as they are multi-potent and can differentiate to create many components of the tumor microenvironment including fibroblasts, myofibroblasts and adipocytes. CA-MSCs, compared to normal MSCs, express high levels of BMP proteins and promote tumor growth by increasing numbers of cancer stem-like cells (CSCs). We now define a CA-MSC BMP4: ovarian tumor cell Hedgehog (HH) positive feedback loop critical to the cancer promoting functions of CA-MSCs. We demonstrate that CA-MSC expression of BMP4 is induced by ovarian tumor cell-secreted Hedgehog (HH). Reciprocally, CA-MSC-derived BMP4 increases ovarian tumor cell HH expression creating a positive feedback loop. Interruption of this loop with either a HH pathway inhibitor (IPI-926 or LDE-225) or BMP4 blocking antibody decreases the induction of CA-MSC-derived BMP4 and tumor-derived HH. This signaling loop is critical to the pro-tumorigenic effects of CA-MSCs as HH inhibition blocked CA-MSC-mediated tumorigenesis and reduced the number of CSCs. Additionally, HH inhibition reversed CA-MSC -induced chemotherapy resistance leading to significant cisplatin response in established platinum-resistant tumors. Collectively, we define a critical positive feedback loop between CA-MSC-derived BMP4 and ovarian tumor cell-secreted HH providing further support for clinical targeting of the HH pathway, particularly in combination with platinum-based chemotherapy, in ovarian cancer.

Citation Format: Lan G. Coffman, Yunjung Choi, Karen Mclean, Marina Pasca di Magliano, Benjamin Allen, Ronald J. Buckanovich. Identification of an ovarian tumor:stromal HH:BMP4 signaling loop critical to ovarian cancer growth and chemotherapy resistance. [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 B60.
Abstract B73: The monoterpene, citral, increases intracellular oxygen radicals and inhibits cancer cell proliferation by inducing apoptosis and endoplasmic reticulum stress .
Authors: Kapur Arvinder , Felder Mildred , Fass Lucas , kaur Justanjyot , Czarnecki Austin , Rathi Kavya , Patankar Manish
Published: May 2016

The terpene-enriched steam distilled extract of ginger rhizomes has potent anti-tumor activity. Screening of the components of ginger extract demonstrated citral, a commonly used food flavoring agent, as the major monoterpene that inhibits proliferation of human and murine cancer cell lines A2780, ECC-1, OVCAR-3, SKOV-3, ID8 and MOVCAR. Citral initiates a rapid decrease in intracellular levels of glutathione and a corresponding increase in oxygen radicals. In wild-type p53-expressing ECC-1 cells, citral treatment increases phosphorylation of the Ser-15 residue of p53 and causes apoptosis. Inhibition of intracellular oxygen radicals by N-acetylcysteine and p53 activity by pifithrin-α inhibits citral-induced apoptosis in ECC-1 cells. Apoptosis in mutant p53 (Arg248Glu) expressing OVCAR-3 cells was also inhibited by N-acetylcysteine and was associated with a decrease in phosphorylation of Ser-15 of p53. Finally, in cells not expressing p53, citral inhibited proliferation, but not through apoptosis. Instead in the p53-negative SKOV-3 cells, citral treatment caused endoplasmic reticulum stress indicated by increase in phosphorylation of eIF2α and the expression of CHOP, GADD45, EDEM, ATF4 and Hsp90 and increased ATG5 and LC3-II suggesting the cells were undergoing autophagy. The study identifies the mechanism that allows citral to produce its cytotoxic effects. Combined with our recent results that nanoparticle-encapsulated citral decreases in vivo growth of 4T1 murine breast tumors, the results from the current study suggest that citral and its analogs be considered as chemotherapeutic agents. Since citral mediates its cytotoxic effects primarily by inducing oxidative stress, it is likely that this monoterpenes and its derivatives can be used for the treatment of a variety of solid tumors including ovarian cancer.

Citation Format: Arvinder Kapur, Mildred Felder, Lucas Fass, Justanjyot kaur, Austin Czarnecki, Kavya Rathi, Manish Patankar. The monoterpene, citral, increases intracellular oxygen radicals and inhibits cancer cell proliferation by inducing apoptosis and endoplasmic reticulum stress . [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 B73.
Abstract B82: Application of modulated electro-hyperthermia for the cellular target therapy in ovarian cancer cells.
Authors: Yang Wookyeom , Chay Doo Byung , Cho Hanbyoul , Kim Sunghoon , Kong Jinkyoung , Son Geumseon , Choi Jihui , Jae-hoon. Kim
Published: May 2016

Background: Oncothermia as modulated electro-hyperthermia is an anti-cancer therapy that was approved by TUV-SUD in Germany, Health Canada in Canada, and Therapeutic Goods Administration in Australian. Oncothermia induces apoptosis via destroying the plasma membrane of cancer cells and leads to accumulation of heat-induced damages mostly in cells located in the tumor tissue while providing minimal damages to the surrounding normal tissue. Thus, oncothermia has recently become a potentially effective therapeutic tool for cancer.

Methods: LabEHY-100, an oncothermia device from Oncotherm (Germany & Hungary), was used for all in vitro studies. Ovarian cells were exposed to thermal damage induced by LabEHY-100, and subsequently, the cancer cells were analyzed in terms of viability, levels of apoptosis, autophagic markers and cell cycle status. In addition, xenograft tumors which generated by OVCAR-3 and patients derived tumor, were exposed to thermal damage induced by LabEHY-100 after which the tumor progression was monitored. The efficacy of combination therapy using both oncothermia and 3-methyladenine (3-MA), an autophagy inhibitor, was assessed using crystal violet assay.

Results: Our studies showed that oncothermia resulted in growth inhibition in ovarian cancer cell tested. Apoptotic markers such as cleaved caspase-3 and PARP were upregulated in cells exposed to oncothermia compared to the control cells exposed to hyperthermia. Oncothermia also led to reduction in the mass and the volume of the tumors in the mouse transplanted with xenografts derived from cancer cells and ovarian cancer patient tumors. FACS analysis showed that cell cycles of these cells were not disrupted by oncothermia. Still there was a significant increase in the number of sub-G1 population, which consisted of dying cells including apoptotic cells. However, the xenograft cells recovered from cellular damage even after inducing autophagy via oncothermia. Combined treatment with oncothermia and 3-MA, a autophagy inhibitor, was more effective in inhibiting cancer cell growth than treatment with each alone.

Conclusion: Oncothermia can potentially be an effective therapy for ovarian cancer cells.

Conflict of interest : We obtained funding and in vitro device for electro-hyperthermia from HOSPICARE. Co., Ltd. (Seoul, Republic of Korea).

Citation Format: Wookyeom Yang, Doo Byung Chay, Hanbyoul Cho, Sunghoon Kim, Jinkyoung Kong, Geumseon Son, Jihui Choi, Kim Jae-hoon. Application of modulated electro-hyperthermia for the cellular target therapy in ovarian cancer cells. [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 B82.
Abstract IA02: Genomic classification of ovarian cancer.
Authors: Bowtell David D. L.
Published: May 2016

Human cancers have been classified for hundreds of years primarily by their anatomical location, and more recently by morphological criteria and the extent of local and distant spread. As cancer is quintessentially a genetic disease, genomics has allowed a reclassification of human cancers, including ovarian cancer, based on gene expression, epigenetic modification, mutational and copy number profiles. The presentation will describe how genomic analyses have helped highlight important molecular distinctions between and within histological subtypes of ovarian cancer, improved the diagnosis of rare subtypes, identified molecular subtypes with different biological properties and clinical outcomes, elucidated driver mutations in primary and recurrent disease, and suggested new approaches to the clinical management of ovarian cancer.

Citation Format: David D. L. Bowtell. Genomic classification of ovarian cancer. [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 IA02.
Abstract IA04: Targeting DNA repair in ovarian cancer therapy.
Authors: D'Andrea. Alan D.
Published: May 2016

Large-scale genomic studies have shown that half of epithelial ovarian cancers (EOCs) have alterations in genes regulating homologous recombination (HR) repair. Loss of HR accounts for the genomic instability and replicative stress of EOCs and for their cellular hyperdependence on alternative poly-ADP ribose polymerase (PARP)-mediated DNA repair mechanisms. On the basis of this hyperdependence, in 2014, the FA approved the PARP inhibitor, olaparib, for patients with advanced ovarian cancer associated with BRCA1 and BRCA2 germline mutations, whose tumors are HR deficient. Previous studies have implicated the DNA polymerase POLQ in an error-prone pathway required for the repair of DNA double-strand breaks, referred to as alternative endjoining (alt-EJ). In Drosophila melanogaster and Caenorhabditis elegans, POLQ functions in alt-EJ and in the maintenance of genome stability at sites of G-quadruplex structures. Whether POLQ interacts with canonical DNA repair pathways to prevent genomic instability at stalled replication forks has remained unknown. We have recently demonstrated an inverse correlation between HR activity and POLQ expression in EOCs (Ceccaldi R. et al, Nature, 518: 258-262, 2015). While knockdown of POLQ in HR-proficient cells upregulates HR activity and RAD51 nucleofilament assembly, knockdown of POLQ in HR-deficient EOCs results in enhanced cell death. Consistent with these results, genetic inactivation of an HR gene (Fancd2) and Polq in mice results in embryonic lethality. Moreover, POLQ contains a repeat of RAD51 binding motifs, and it blocks D-loop formation and recombination. Importantly, PARP1 activity is required for the recruitment of POLQ to sites of DNA repair, accounting, in part, for the PARP1 hyperdependence of HR-deficient ovarian tumor cells. Taken together, these results reveal a synthetic lethal relationship between the HR pathway and PARP1/POLQ-mediated alternative end-joining in EOCs, and identify POLQ as a novel druggable target for ovarian cancer therapy. Such inhibitors may be useful in the treatment of PARP inhibitor-resistant ovarian cancers.

Citation Format: Alan D. D'Andrea. Targeting DNA repair in ovarian cancer therapy. [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 IA04.
Abstract IA08: PI3K- and PARP-inhibitors for the treatment of women cancers.
Authors: Wulf Gerburg M. , Juvekar Ashish , Cantley Lewis C. , Matulonis Ursula A.
Published: May 2016

Amplification of PIK3CA is highly prevalent in ovarian cancer and isoform-specific and pan-PI3K inhibitors have entered clinical trials. However, identifying tumor subtypes and biological mechanisms that predict for response to PI3K inhibitors as single agents or in combination has been a challenge.

We previously reported that combining a phophoinositide 3-kinase (PI3K) inhibitor with a poly ADP ribose polymerase (PARP)-inhibitor enhanced DNA damage and cell death in breast cancers that have genetic aberrations in BRCA1 and TP53. We now show that the enhanced DNA damage induced by PI3K inhibitors in this mutational background is a consequence of impaired production of deoxynucleotides needed for DNA synthesis and DNA repair. Inhibition of PI3K causes a reduction in all four deoxynucleotide triphosphates (dATP, dTTP, dGTP and dCTP), while inhibition of AKT is less effective than inhibition of PI3K in suppressing nucleotide synthesis and inducing DNA damage. Carbon flux studies reveal that PI3K-inhibition disproportionately affects the non-oxidative pentose phosphate pathway (non-ox PPP) that delivers ribose-5-posphate required for base ribosylation. In vivo in a mouse model of BRCA1-linked triple-negative breast cancer combined PI3K- and PARP-inhibition was superior to either agent alone to induce durable remissions of established tumors. Our data indicate that PI3K inhibitors induce DNA damage in tumors that have defects in DNA damage repair pathways and that they do so by impairing the production of Ribose-5-phosphate and amino acids needed for deoxynucleotide synthesis. An ongoing phase I/II study (NCT01623349, PI: Matulonis) examines the safety and toxicity of a PI3K/Parp-inhibitor combination in ovarian and breast cancer.

Citation Format: Gerburg M. Wulf, Ashish Juvekar, Lewis C. Cantley, Ursula A. Matulonis. PI3K- and PARP-inhibitors for the treatment of women cancers. [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 IA08.
Abstract IA11: Deciphering the immunobiology of ovarian cancer to create effective immunotherapy.
Authors: Powell Daniel J.
Published: May 2016

Deep interrogations of the immunological landscape of human ovarian cancer has revealed the importance of the immune system in tumor control. In particular, the finding that intratumoral accumulation of tumor-infiltrating lymphocytes (TILs) is associated with improved survival in ovarian and various other cancer types supports the notions that spontaneously-arising T-cells with antitumor activity reside in cancer and control tumor outgrowth, and that this prognostic biomarker can be reinforced though administration of immunotherapy. Since this association was first described more than a decade ago, more sophisticated analyses have refined our understanding of the complex interplay between ovarian cancer cells and the host immune system. This includes the recent elucidation of a phenotypically-defined subset of ovarian cancer associated TILs that exhibit specific reactivity against autologous tumor cells, which represent a potential source for tumor-reactive T cell for use in the adoptive immunotherapy of ovarian cancer. Additionally, the discovery that the antigenic repertoire recognized by TILs is comprised of both shared tumor associated antigens and patient specific neo-antigens derived from mutated self-proteins uniquely expressed by the ovarian cancer cell has rationalized the clinical testing of highly personalized vaccines. While induction of patient-specific T cell responses holds significant promise, further analysis has revealed that the ovarian cancer microenvironment harbors a myriad of immunosuppressive factors that have the potential to thwart otherwise effective T cell responses. Ovarian cancer cells downregulate the expression of molecules associated with immune recognition and preferentially recruit inhibitory cells such as regulatory T cells to the tumor site. Ovarian cancer cells also express multiple negative immunoregulatory ligands that interact with reciprocal receptors expressed preferentially by the subset of tumor-reactive T cells and thereby limit their activity, however, with a new cadre of antibodies that effective block these axes of immunosuppression, clinical trials are underway to determine the efficacy of this form of passive immunomodulation and encouraging results are emerging. Taken together, detailed exploration of the immunobiology of the ovarian cancer microenvironment has increased our understanding of the roles of the cellular and molecular elements that influence tumor outgrowth. This knowledge serves as a roadmap for the rational development of effective immunotherapeutic approaches in ovarian cancer.

Citation Format: Daniel J. Powell, Jr. Deciphering the immunobiology of ovarian cancer to create effective immunotherapy. [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 IA11.
Abstract IA15: Rarer, yet both interesting and relevant: Other ovarian cancers.
Authors: Huntsman David G.
Published: May 2016

Although high grade serous ovarian carcinoma is justifiably the focus of most research and clinical attention, other histotypes represent significant clinical challenges. An overview of advances in our understanding of germ cell, sex cord-stromal and non-serous cancers will be presented. Specific attention will be placed on granulosa cell tumor and small cell hypercalcemic ovarian cancer where molecular features have both redefined those diseases and offered hope for more rational treatment plans.

Citation Format: David G. Huntsman. Rarer, yet both interesting and relevant: Other ovarian cancers. [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 IA15.
Abstract IA18: Thinking outside the box: New areas in prevention research.
Authors: Tworoger Shelley S.
Published: May 2016

Due to its high fatality, ovarian cancer is a key public health problem. Identifying high-risk women is particularly important, as bilateral salpingo-oophorectomy reduces risk by >90%; However, because this surgery has other negative health consequences (e.g., increased risk of heart disease), it is indicated only for women with BRCA or other high-risk genetic variants. Unfortunately, current etiologic understanding of ovarian cancer and its risk factors does not have the predictive capacity needed to identify women who could benefit from prophylactic surgery. Thus the primary goal of prevention research is to identify new, potentially modifiable risk factors for ovarian cancer that have the capability to both improve risk prediction and create new opportunities for other prevention modalities. A number of challenges, including tumor heterogeneity, require “out-of-the-box” approaches to conducting prevention research. In this talk, I will discuss several examples of opportunities to advance prevention research including novel approaches to characterizing ovarian tumors in epidemiologic studies, using basic research to motivate the evaluation of new potential risk factors, and considering etiologically susceptible windows of exposure. Finally, I will discuss existing consortial resources within the ovarian cancer research community that are open to collaboration.

Citation Format: Shelley S. Tworoger. Thinking outside the box: New areas in prevention research. [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 IA18.
Abstract IA24: Developing and deploying experimental models systems towards novel drug discovery in ovarian cancer.
Authors: Drapkin Ronny , Budina Anna , Feng Yi , Doberstein Kai
Published: May 2016

Ovarian cancer carries significant mortality in the absence of effective methods for prevention and screening. Preventive salpingo-oophorectomy is currently the only method known to reduce the risk of ovarian cancer-related death. Histopathological analyses of these surgical specimens indicate that a high proportion of ovarian cancers in women at high risk and in the general population arise from the fallopian tube. This paradigm shift in our understanding of the cell of origin for the most common subtype of ovarian cancer, high-grade serous carcinoma, has sparked a major effort within the research community to develop new and robust model systems to study the fallopian tube epithelium, it susceptibility to neoplastic transformation, and opportunities for therapeutic intervention.

These models include primary cell line cultures, fallopian tube-derived lines, epithelial-stromal co-cultures, genetically-engineered mouse models, and patient-derived tumor xenografts or ‘avatars’. There has also been a re-evaluation of the fidelity of established ovarian cancer cell lines and the need to develop new lines that represent the human disease. Critical to this effort is the need to go beyond genomics and critically evaluate the functional utility of new cell lines.

The deploying of these new models is already have a profound effect on our ability to identify unique susceptibilities in ovarian cancer through genetic screens, chemical screens, and targeted approaches. In addition, the search for novel biomarkers that can play a role in early detection or prognostication is being re-defined by looking at the fallopian tube fimbria as the source.

Citation Format: Ronny Drapkin, Anna Budina, Yi Feng, Kai Doberstein. Developing and deploying experimental models systems towards novel drug discovery in ovarian cancer. [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 IA24.
Abstract IA26: Role of ARID1A in SWI/SNF chromatin remodeling and ovarian cancer.
Authors: Chandler Ronald L. , Raab Jesse , Magnuson Terry
Published: May 2016

ARID1A has emerged as the most frequently mutated chromatin remodeling protein in cancer and as a major tumor suppressor in endometriosis-associated cancers arising from the coelomic epithelium of the female reproductive tract. We have developed and characterized Arid1a conditional (floxed) and hypomorphic (valine-to-glycine substitution or V1068G) mutant mouse alleles. Mutant ARID1AV1068G is stably expressed and capable of assembling into a SWI/SNF complex with core catalytic properties, but nucleosome binding and promoter occupancy by ARID1A-containing SWI/SNF complexes (BAF-A) are reduced. Lowly penetrant hyperplastic outgrowths are observed within the oviducts of aged, hypomorphic Arid1aV1068G/+ females, but no tumors have been detected. Conversely, conditional inactivation of ARID1A in the ovarian surface epithelium (OSE) via intrabursal Adenovirus-CRE injection is not sufficient for tumor formation, but requires concurrent activation of the phosphoinositide 3-kinase catalytic subunit, PIK3CA. Remarkably, mouse ovarian tumor cells carrying the ARID1A-PIK3CA mutational pattern are genomically stable, chemoresistant and dependent on cell autonomous Interleukin 6 (IL-6) signaling pathway for continued growth and survival. We have further shown that concurrent ARID1A loss and PIK3CA activation leads to an epithelial-to-mesenchymal transformation phenotype in isolated OSE cells. Our data highlight potential gene dose-dependent differences in ARID1A tumor suppressor activity in coelomic epithelial cell derivatives and suggest that many key features of ovarian tumorigenesis are conferred by the ARID1A-PIK3CA mutational pattern. Hence, our efforts to parse the tumor suppressor roles of ARID1A-containing SWI/SNF complexes in endometriosis-associated gynecologic cancers should extend to the Müllerian-derived ductal epithelium and include activating phosphoinositide 3-kinase mutations.

Citation Format: Ronald L. Chandler, Jesse Raab, Terry Magnuson. Role of ARID1A in SWI/SNF chromatin remodeling and ovarian cancer. [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 IA26.
Abstract PR08: Evidence for extra-ovarian origin and peritoneal metastases that precede ovarian carcinomas in high-grade serous ovarian cancer.
Authors: Chien Jeremy , Shridhar Viji , Mariani Andrea
Published: May 2016

High-grade serous (HGS) ovarian cancer is the most lethal form of epithelial ovarian cancer because it represents the most common histologic subtype and usually present at an advanced stage. Due to its advanced stage presentation, HGS ovarian cancer has been described as arising de novo from undefined precursor lesions that progress rapidly to advanced disease. To gain insights into clonal heterogeneity and progression to distant metastases, we analyzed single nucleotide variations (SNVs) from nine regions of carcinomas from four patients with HGS ovarian cancer. Three primary sites, three metastases from omentum, and three metastases from bowel were collected from each patient and subjected to RNA sequencing and SNV analysis. Although a modest number (23.62%) of SNVs are shared within the same anatomic site, only limited number (1.26%) of SNVs are shared among all 9 sites, suggesting a high degree of intratumor heterogeneity in these patients. Truncal mutations, such as TP53 mutations, are shared among all sites and observed at high allele frequencies. In addition, mutations in genes associated with epigenetic modifiers, such as SETD2, CHD8, KDM5A, SMARCA1 and ARID5B are observed as truncal mutations in these patients. Phylogenetic tree reconstruction of tumors from various sites suggests a concurrent ovarian and peritoneal metastases in one patient and peritoneal metastases preceding the ovarian carcinomas in three other patients. Finally, subclone inference from multi-region sequencing indicates the presence of multiple subclones at each site in these patients. Dominant subclones, present at metastases, are often ancestral clones in the clonal hierarchy, further providing evidence that peritoneal spreading occurs early in the clonal expansion. Collectively, these results provide evidence for early peritoneal spreading that often precedes ovarian carcinomas in HGS ovarian cancer.

This abstract is also presented as Poster B44.

Citation Format: Jeremy Chien, Viji Shridhar, Andrea Mariani. Evidence for extra-ovarian origin and peritoneal metastases that precede ovarian carcinomas in high-grade serous ovarian cancer. [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 PR08.
Abstract PR09: Ovarian cancer prevention: is it time for population screening for BRCA mutations?
Authors: Campbell Ian G. , Mitchell Gillian , Trainer Alison , James Paul , Thompson Ella
Published: May 2016

The traditional model of familial ovarian cancer practice involves ascertaining high-risk individuals based on family history. However, most individuals who carry a BRCA1 or BRCA2 mutation will not have a family history of ovarian or other cancer in a close relative. Moving germline testing from the familial cancer center to the population will result in many essentially unanticipated findings of great significance in regards to the risk of ovarian cancer in healthy relatives. To date there have been no large studies that have directly measured the frequency of BRCA1 and BRCA2 mutations in a cancer-free general population. As a first step toward population based BRCA1 or BRCA2 screening, we sequenced the entire coding region of these genes in 1,997 cancer-free Australian women recruited from the lifepool study (www.lifepool.org) which is a cohort of women attending the Australian population based mammographic screening program. Sequencing data were filtered for known pathogenic or novel loss of function mutations. Thirteen individuals were identified with pathogenic mutations in either BRCA1 (4 mutations) or BRCA2 (9 mutations), which is consistent with previous indirect estimates for Caucasian populations but to our knowledge this is the largest direct assessment of their prevalence.

Interestingly, the self-reported cancer family history of the majority of the 13 mutation positive women was unremarkable. All 13 women subsequently accepted an invitation to attend a Familial Cancer Centre and then proceeded to formal clinical genetic testing.

A population carrier frequency of 0.65% for mutations in BRCA1 and BRCA2, coupled with the rapidly declining costs of gene panel sequencing, suggests that population-based screening for these genes will be a highly cost effective way of reducing the incidence of ovarian (and breast) cancer through preventative strategies.

Citation Format: Ian G. Campbell, Gillian Mitchell, Alison Trainer, Paul James, Ella Thompson. Ovarian cancer prevention: is it time for population screening for BRCA mutations? [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 PR09.