ROR2/Wnt5a Signaling Regulates Directional Cell Migration and Early Tumor Cell Invasion in Ovarian Cancer

Adhesion to and clearance of the mesothelial monolayer are key early events in metastatic seeding of ovarian cancer. ROR2 is a receptor tyrosine kinase that interacts with Wnt5a ligand to activate noncanonical Wnt signaling and has been previously shown to be upregulated in ovarian cancer tissue. However, no prior study has evaluated the mechanistic role of ROR2 in ovarian cancer. Through a cellular high-throughput genetic screen, we independently identified ROR2 as a driver of ovarian tumor cell adhesion and invasion. ROR2 expression in ovarian tumor cells serves to drive directed cell migration preferentially toward areas of high Wnt5a ligand, such as the mesothelial lined omentum. In addition, ROR2 promotes ovarian tumor cell adhesion and clearance of a mesothelial monolayer. Depletion of ROR2, in tumor cells, reduces metastatic tumor burden in a syngeneic model of ovarian cancer. These findings support the role of ROR2 in ovarian tumor cells as a critical factor contributing to the early steps of metastasis. Therapeutic targeting of the ROR2/Wnt5a signaling axis could provide a means of improving treatment for patients with advanced ovarian cancer.

IMPLICATIONS

This study demonstrates that ROR2 in ovarian cancer cells is important for directed migration to the metastatic niche and provides a potential signaling axis of interest for therapeutic targeting in ovarian cancer.

DDR2-regulated arginase activity in ovarian cancer-associated fibroblasts promotes collagen production and tumor progression

Ovarian cancer has poor survival outcomes particularly for advanced stage, metastatic disease. Metastasis is promoted by interactions of stromal cells, such as cancer-associated fibroblasts (CAFs) in the tumor microenvironment (TME), with tumor cells. CAFs play a key role in tumor progression by remodeling the TME and extracellular matrix (ECM) to result in a more permissive environment for tumor progression. It has been shown that fibroblasts, in particular myofibroblasts, utilize metabolism to support ECM remodeling. However, the intricate mechanisms by which CAFs support collagen production and tumor progression are poorly understood. In this study, we show that the fibrillar collagen receptor, Discoidin Domain Receptor 2 (DDR2), promotes collagen production in human and mouse omental CAFs through arginase activity. CAFs with high DDR2 or arginase promote tumor colonization in the omentum. In addition, DDR2-depleted CAFs had decreased ornithine levels leading to decreased collagen production and polyamine levels compared to WT control CAFs. Tumor cell invasion was decreased in the presence CAF conditioned media (CM) depleted of DDR2 or arginase-1, and this invasion defect was rescued in the presence of CM from DDR2-depleted CAFs that constitutively overexpressed arginase-1. Similarly, the addition of exogenous polyamines to CM from DDR2-depleted CAFs led to increased tumor cell invasion. We detected SNAI1 protein at the promoter region of the arginase-1 gene, and DDR2-depleted CAFs had decreased levels of SNAI1 protein at the arginase-1 promoter region. Furthermore, high stromal arginase-1 expression correlated with poor survival in ovarian cancer patients. These findings highlight how DDR2 regulates collagen production by CAFs in the tumor microenvironment by controlling the transcription of arginase-1, and CAFs are a major source of arginase activity and L-arginine metabolites in ovarian cancer models.

Epigenetic regulation during cancer transitions across 11 tumour types

Chromatin accessibility is essential in regulating gene expression and cellular identity, and alterations in accessibility have been implicated in driving cancer initiation, progression and metastasis1-4. Although the genetic contributions to oncogenic transitions have been investigated, epigenetic drivers remain less understood. Here we constructed a pan-cancer epigenetic and transcriptomic atlas using single-nucleus chromatin accessibility data (using single-nucleus assay for transposase-accessible chromatin) from 225 samples and matched single-cell or single-nucleus RNA-sequencing expression data from 206 samples. With over 1 million cells from each platform analysed through the enrichment of accessible chromatin regions, transcription factor motifs and regulons, we identified epigenetic drivers associated with cancer transitions. Some epigenetic drivers appeared in multiple cancers (for example, regulatory regions of ABCC1 and VEGFA; GATA6 and FOX-family motifs), whereas others were cancer specific (for example, regulatory regions of FGF19, ASAP2 and EN1, and the PBX3 motif). Among epigenetically altered pathways, TP53, hypoxia and TNF signalling were linked to cancer initiation, whereas oestrogen response, epithelial-mesenchymal transition and apical junction were tied to metastatic transition. Furthermore, we revealed a marked correlation between enhancer accessibility and gene expression and uncovered cooperation between epigenetic and genetic drivers. This atlas provides a foundation for further investigation of epigenetic dynamics in cancer transitions.

Stromal DDR2 Promotes Ovarian Cancer Metastasis through Regulation of Metabolism and Secretion of Extracellular Matrix Proteins

Ovarian cancer is the leading cause of gynecologic cancer-related deaths. The propensity for metastasis within the peritoneal cavity is a driving factor for the poor outcomes associated with this disease, but there is currently no effective therapy targeting metastasis. In this study, we investigate the contribution of stromal cells to ovarian cancer metastasis and identify normal stromal cell expression of the collagen receptor, discoidin domain receptor 2 (DDR2), that acts to facilitate ovarian cancer metastasis. In vivo, global genetic inactivation of Ddr2 impairs the ability of Ddr2-expressing syngeneic ovarian cancer cells to spread throughout the peritoneal cavity. Specifically, DDR2 expression in mesothelial cells lining the peritoneal cavity facilitates tumor cell attachment and clearance. Subsequently, omentum fibroblast expression of DDR2 promotes tumor cell invasion. Mechanistically, we find DDR2-expressing fibroblasts are more energetically active, such that DDR2 regulates glycolysis through AKT/SNAI1 leading to suppressed fructose-1,6-bisphosphatase and increased hexokinase activity, a key glycolytic enzyme. Upon inhibition of DDR2, we find decreased protein synthesis and secretion. Consequently, when DDR2 is inhibited, there is reduction in secreted extracellular matrix proteins important for metastasis. Specifically, we find that fibroblast DDR2 inhibition leads to decreased secretion of the collagen crosslinker, LOXL2. Adding back LOXL2 to DDR2 deficient fibroblasts rescues the ability of tumor cells to invade. Overall, our results suggest that stromal cell expression of DDR2 is an important mediator of ovarian cancer metastasis.

IMPLICATIONS

DDR2 is highly expressed by stromal cells in ovarian cancer that can mediate metastasis and is a potential therapeutic target in ovarian cancer.

Reproductive Scientist Development Program: Bridging the Gap to the Physician Scientist Career

Career development awards are a successful strategy to facilitate the advancement of physician-scientists trained in obstetrics and gynecology (OBGYN) toward a path of investigative independence. While these funding mechanisms can be effective approaches to developing the career of future OBGYN scientists, optimizing the probability of obtaining these awards requires determining the appropriate career development award for the applicant. There are many details and opportunities that need to be considered when deciding on the appropriate award. Some of the most sought-after awards are those that integrate career development and applied research, such as the K-series awards supported by the National Institutes of Health (NIH). A quintessential example of an NIH-funded mentor-based career development award to support the scientific training of an OBGYN physician-scientist is the Reproductive Scientist Development Program (RSDP). In this study, we provide data on the academic achievements of past and present RSDP scholars and discuss the structure, impact, and future of the RSDP, a federally funded K12 program dedicated to women's health for OBGYN scientific investigators. As healthcare is changing and physician-scientists comprise a unique and valuable part of the biomedical workforce, programs such as the RSDP are critical to maintaining a well-trained pipeline of OBGYN scientists to maintain and challenge the leading edge of medicine, science, and biology.

Genetic characterization of primary and metastatic high-grade serous ovarian cancer tumors reveals distinct features associated with survival

High-grade serous ovarian cancer (HGSC) is the most lethal histotype of ovarian cancer and the majority of cases present with metastasis and late-stage disease. Over the last few decades, the overall survival for patients has not significantly improved, and there are limited targeted treatment options. We aimed to better characterize the distinctions between primary and metastatic tumors based on short- or long-term survival. We characterized 39 matched primary and metastatic tumors by whole exome and RNA sequencing. Of these, 23 were short-term (ST) survivors (overall survival (OS) < 3.5 years) and 16 were long-term (LT) survivors (OS > 5 years). We compared somatic mutations, copy number alterations, mutational burden, differential gene expression, immune cell infiltration, and gene fusion predictions between the primary and metastatic tumors and between ST and LT survivor cohorts. There were few differences in RNA expression between paired primary and metastatic tumors, but significant differences between the transcriptomes of LT and ST survivors in both their primary and metastatic tumors. These findings will improve the understanding of the genetic variation in HGSC that exist between patients with different prognoses and better inform treatments by identifying new targets for drug development.

High visceral fat to subcutaneous fat ratios portend a poor prognosis in patients with advanced endometrial cancer

OBJECTIVES

Visceral adiposity has been established as a predictor of outcomes in various cancers. We aimed to determine the association of radiographic measurements of visceral fat with clinical outcomes in patients with endometrial cancer.

METHODS

A retrospective review of patients with stage III-IV endometrial cancer who underwent surgery between 2004 and 2014 was performed. Visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and total adipose tissue (TAT;VAT+SAT) were assessed on preoperative computed tomography (CT) scans. Exploratory analysis was performed to establish the optimal cut-off values for VAT, SAT, and TAT to identify patients with poor prognostic body composition. Survival rates were analyzed using Kaplan-Meier analysis, log-rank tests, and cox-regression.

RESULTS

Eighty-three patients were included. Forty-two (51%) patients had a low VAT/SAT ratio (<0.45) and 41 (49.4%) had a high VAT/SAT ratio (>0.45). There were no significant differences in demographics between the groups. The mean VAT, SAT, and TAT were 176.3 cm2, 379.3 cm2, and 555.3 cm2 respectively. Compared to patients with low VAT/SAT ratios, patients with high VAT/SAT ratios had a shorter recurrence-free survival (median 29.6 vs 32.3 months, P = 0.01) and shorter overall survival (median 56 vs 93.7 months, P = 0.03).

CONCLUSIONS

Visceral fat measurements are predictive of outcomes in patients with advanced stage endometrial cancer. Specifically, VAT to SAT ratios are predictive of overall survival. Future studies should be pursued to identify potential therapeutic targets and biological mechanisms that underlie obesity's relationship with endometrial cancer.

Community access to primary care is an important geographic disparity among ovarian cancer patients undergoing cytoreductive surgery

Objective

Given the importance of understanding neighborhood context and geographic access to care on individual health outcomes, we sought to investigate the association of community primary care (PC) access on postoperative outcomes and survival in ovarian cancer patients.

Methods

This was a retrospective cohort study of Stage III-IV ovarian cancer patients who underwent surgery at a single academic, tertiary care hospital between 2012 and 2015. PC access was determined using a Health Resources and Services Administration designation. Outcomes included 30-day surgical and medical complications, extended hospital stay, ICU admission, hospital readmission, progression-free and overall survival. Descriptive statistics and chi-squared analyses were used to analyze differences between patients from PC-shortage vs not PC-shortage areas.

Results

Among 217 ovarian cancer patients, 54.4 % lived in PC-shortage areas. They were more likely to have Medicaid or no insurance and live in rural areas with higher poverty rates, significantly further from the treating cancer center and its affiliated hospital. Nevertheless, 49.2 % of patients from PC-shortage areas lived in urban communities. Residing in a PC-shortage area was not associated with increased surgical or medical complications, ICU admission, or hospital readmission, but was linked to more frequent prolonged hospitalization (26.3 % vs 14.1 %, p = 0.04). PC-shortage did not impact progression-free or overall survival.

Conclusions

Patients from PC-shortage areas may require longer inpatient perioperative care in order to achieve the same 30-day postoperative outcomes as patients who live in non-PC shortage areas. Community access to PC is a critical factor to better understanding and reducing disparities among ovarian cancer patients.

State of the Biomarker Science in Ovarian Cancer: A National Cancer Institute Clinical Trials Planning Meeting Report

PURPOSE

Despite therapeutic advances in the treatment of ovarian cancer (OC), 5-year survival remains low, and patients eventually die from recurrent, chemotherapy-resistant disease. The National Cancer Gynecologic Cancer Steering Committee identified the integration of scientifically defined subgroups as a top strategic priority in clinical trial planning.

METHODS

A group of experts was convened to review the scientific literature in OC to identify validated predictive biomarkers that could inform patient selection and treatment stratification. Here, we report on these findings and their potential for use in future clinical trial design on the basis of hierarchal evidence grading.

RESULTS

The biomarkers were classified on the basis of mechanistic targeting, including DNA repair and replication stress, immunotherapy and tumor microenvironment, oncogenic signaling, and angiogenesis. Currently, BRCA mutations and homologous recombination deficiency to predict poly (ADP-ribose) polymerase inhibitor response are supported in OC by the highest level of evidence. Additional biomarkers of response to agents targeting the pathways above have been identified but require prospective validation.

CONCLUSION

Although a number of biomarkers of response to various agents in OC have been described in the literature, high-level evidence for the majority is lacking. This report highlights the unmet need for identification and validation of predictive biomarkers to guide therapy and future trial design in OC.

Gynecologic oncology patient perspectives and knowledge on advance care planning: A quality improvement intervention

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Gynecologic oncology patients prefer advance care planning (ACP) communication outpatient with their gynecologic oncologist.

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A quality improvement intervention offering advance care planning resources increased ACP discussions.

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A quality improvement intervention offering advance care planning resources improved ACP document creation proficiency.

Objectives

Assess and improve advance care planning (ACP) awareness and uptake among gynecologic oncology patients.

Methods

Using a quality improvement Plan-Do-Check-Act framework, we completed a single institution needs assessment and intervention. The needs assessment was a 26-question survey assessing baseline ACP knowledge and preferences of gynecologic oncology patients. We used this survey to implement an outpatient intervention in which patients were offered ACP resources (pamphlet, discussion with their gynecologic oncologist, and/or social work referral). We conducted a post-intervention survey among patients who had and had not received ACP resource(s) to assess whether our intervention increased ACP knowledge, discussions, or uptake.

Results

Among 106 patients surveyed in the needs assessment, 33 % had ACP documents, 26 % had discussed ACP with a physician, and 82 % thought discussing ACP was important. The majority preferred these conversations in the outpatient setting (52 %) with their gynecologic oncologist (80 %) instead of nurses or trainees. In the intervention, 526 patients were offered ACP resources. Compared to women who did not receive resources (n = 324), patients who received ACP resource(s) (n = 202) were more likely to have ACP discussions with their gynecologic oncologist (38 % vs 68 %, P = 0.001) and had greater proficiency regarding how to create ACP documents (median score 5/10 vs 8/10, P = 0.048), although they were no more likely to have ACP documented in their electronic medical record (27 % vs 9 %, p = 0.08).

Conclusions

ACP uptake among gynecologic oncology patients is low, but ACP discussions with an oncologist during outpatient visits are important to patients and improve their knowledge regarding completing ACP documents.

GAS6-AXL Inhibition by AVB-500 Overcomes Resistance to Paclitaxel in Endometrial Cancer by Decreasing Tumor Cell Glycolysis

Chemotherapy is often ineffective in advanced-stage and aggressive histologic subtypes of endometrial cancer. Overexpression of the receptor tyrosine kinase AXL has been found to be associated with therapeutic resistance, metastasis, and poor prognosis. However, the mechanism of how inhibition of AXL improves response to chemotherapy is still largely unknown. Thus, we aimed to determine whether treatment with AVB-500, a selective inhibitor of GAS6-AXL, improves endometrial cancer cell sensitivity to chemotherapy particularly through metabolic changes. We found that both GAS6 and AXL expression were higher by immunohistochemistry in patient tumors with a poor response to chemotherapy compared with tumors with a good response to chemotherapy. We showed that chemotherapy-resistant endometrial cancer cells (ARK1, uterine serous carcinoma and PUC198, grade 3 endometrioid adenocarcinoma) had improved sensitivity and synergy with paclitaxel and carboplatin when treated in combination with AVB-500. We also found that in vivo intraperitoneal models with ARK1 and PUC198 cells had decreased tumor burden when treated with AVB-500 + paclitaxel compared with paclitaxel alone. Treatment with AVB-500 + paclitaxel decreased AKT signaling, which resulted in a decrease in basal glycolysis. Finally, multiple glycolytic metabolites were lower in the tumors treated with AVB-500 + paclitaxel than in tumors treated with paclitaxel alone. Our study provides strong preclinical rationale for combining AVB-500 with paclitaxel in aggressive endometrial cancer models.

DDR2 Expression in Cancer-Associated Fibroblasts Promotes Ovarian Cancer Tumor Invasion and Metastasis through Periostin-ITGB1

Ovarian cancer has the highest mortality of all gynecologic malignancies. As such, there is a need to identify molecular mechanisms that underlie tumor metastasis in ovarian cancer. Increased expression of receptor tyrosine kinase, DDR2, has been associated with worse patient survival. Identifying downstream targets of DDR2 may allow specific modulation of ovarian cancer metastatic pathways. Additionally, stromal cells play a critical role in metastasis. The crosstalk between tumor and stromal cells can lead to tumor progression. We first identified that tumor cells co-cultured with DDR2-expressing fibroblasts had lower periostin expression when compared to tumor cells co-cultured with DDR2-depleted fibroblasts. We confirmed that DDR2 regulates POSTN expression in ovarian cancer-associated fibroblasts (CAFs). We found that mesothelial cell clearance and invasion by tumor cells were enhanced three-fold when DDR2 and POSTN-expressing CAFs were present compared to DDR2 and POSTN-depleted CAFs. Furthermore, DDR2-depleted and POSTN-overexpressing CAFs co-injected with ovarian tumor cells had increased tumor burden compared to mice injected with tumor cells and DDR2 and POSTN-depleted CAFs. Furthermore, we demonstrated that DDR2 regulates periostin expression through integrin B1 (ITGB1). Stromal DDR2 is highly correlated with stromal POSTN expression in ovarian cancer patient tumors. Thus, DDR2 expression in CAFs regulates the steps of ovarian cancer metastasis through periostin.

Abstract 168: DDR2 regulates angiogenesis via HSP-90 modulation in ovarian cancer

Ovarian cancer is often diagnosed in later stages and patients have low five-year survival. There is a need to develop better therapies for this patient population. Solid tumors like ovarian cancer respond to hypoxia by inducing the sprouting of new blood cells. This process is called angiogenesis. Angiogenesis leads to formation of disordered and immature vessels that precludes efficient drug delivery. Prior work has shown that overexpressing DDR2 in endothelial cells leads to increased angiogenic activity, measured by tube formation and sprouting. We show that DDR2 expression in ovarian cancer tumor cells modulates angiogenic activity in endothelial cells. Human umbilical vein endothelial cells (HUVECs) cultured in conditioned media from DDR2-expressing tumor cells (ES2 shSCRM) have 20% increase in tube length and 18% increase in sprout network area than HUVECs cultured in conditioned media from DDR2-depleted tumor cells (ES2 shDDR2) (P=0.032). This difference in HUVEC angiogenesis is mediated by vascular endothelial growth factor (VEGF). We observed a 16% decrease in VEGF levels in conditioned media from ES2 shDDR2 cells compared to media from ES2 shSCRM cells (P​​&lt;0.0001). DDR2 WT mice bearing ID8 Trp53-/- BRCA2-/- tumors have 53% more CD31+ microvessels than DDR2 KO mice (P​​&lt;0.0001). We also identified that DDR2’s role in angiogenesis is mediated by the Hsp70/90 chaperone machinery. In summary, we have identified that DDR2 regulates angiogenesis in ovarian cancer.

Citation Format: Favour A. Akinjiyan, Ritu M. Dave, Gregory Longmore, Katherine C. Fuh. DDR2 regulates angiogenesis via HSP-90 modulation in ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 168.

Abstract LB081: GAS6-AXL inhibition by AVB-500 overcomes resistance to paclitaxel in endometrial cancer by decreasing tumor cell glycolysis

Objective/Background: Chemotherapy is often ineffective in advanced stage and aggressive histologic subtypes of endometrial cancer. Overexpression of the receptor tyrosine kinase AXL has been found to be associated with therapeutic resistance, metastasis, and poor prognosis in endometrial cancer. Our objective was to identify whether inhibition of AXL through a novel, selective targeted agent, AVB-500, would improve sensitivity to paclitaxel. Additionally, we sought to determine whether the mechanism for this improved sensitivity was through metabolic regulation.

Methods: Immunohistochemistry (IHC) was performed on a tissue microarray containing specimens from patients with primary and metastatic uterine serous carcinoma. Blind scoring was performed by two reviewers. Kaplan-Meier methods were used to generate time-to-event curves. Cell viability was performed with high-grade endometrial, chemo-resistant cell lines, ARK1 and PUC198. Cells were treated with paclitaxel and with AVB-500+paclitaxel. Intraperitoneal (IP) ARK1 or PUC198 tumors were treated with vehicle, AVB-500, paclitaxel, or AVB-500+paclitaxel. A Seahorse Analyzer was used for glycolytic rate assays. Isotope tracing was used for in vivo metabolite abundance quantification.

Results: We found that both GAS6 and AXL expression were higher by IHC in tumors with a poor response to chemotherapy compared to tumors with a good response to chemotherapy (GAS6: 40.9% vs. 30.4%, P=0.012; AXL: 60.7% vs. 42.7%, P=0.013). Median PFS and OS were longer in patients with low GAS6 expressing tumors compared to high GAS6 expressing tumors (PFS: 33.6 mo vs. 10.6 mo, P=0.003; OS: 39.5 mo vs. 27.7 mo, P=0.003). We showed that chemotherapy resistant endometrial cancer cell lines, ARK1 and PUC198 had improved sensitivity and synergy with paclitaxel when treated in combination with AVB-500. ARK1 and PUC198 in vivo IP models had significantly fewer tumors (ARK1: P=0.007; PUC198: P=0.029) and decreased tumor weight (ARK1: P&lt;0.001; PUC198: P=0.006) when treated with AVB-500+paclitaxel vs. paclitaxel alone. Treatment with AVB-500 + paclitaxel decreased AKT signaling which resulted in a decrease in basal glycolysis. Finally, treatment with AVB-500 + paclitaxel decreased multiple glycolytic metabolites, including fructose-1,6-bisphosphate (P=0.002), 3-phosphoglyceric acid (P=0.014), phosphoenolpyruvate (P=0.013), and lactate (P=0.024) vs. treatment with paclitaxel alone.

Conclusions: Our study provides strong pre-clinical rationale for combining AVB-500 with paclitaxel in aggressive endometrial cancer models. Additionally, continued identification of viable biomarkers is critical to the success of targeted therapies such as AVB-500. Given AXL’s role in glucose homeostasis, one or more glycolytic intermediates may prove to be a useful biomarker to help predict sensitivity in patients, thus tailoring who would benefit from this treatment combination.

Citation Format: Shaina F. Bruce, Kevin Cho, Hollie Noia, Elena Lomonosova, Elizabeth Stock, Alyssa Oplt, Barbara Blachut, Mary M. Mullen, Lindsay M. Kuroki, Andrea R. Hagemann, Carolyn K. McCourt, Premal H. Thaker, Dineo Khabele, Matthew A. Powell, David G. Mutch, Leah P. Shriver, Gary J. Patti, Katherine C. Fuh. GAS6-AXL inhibition by AVB-500 overcomes resistance to paclitaxel in endometrial cancer by decreasing tumor cell glycolysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB081.

Abstract 3235: The role of DDR2 in chemoresistant ovarian cancer

Ovarian cancer is the fifth leading cause of cancer death for women in the United States. As many as 80% of ovarian cancer patients experience recurrent disease and the majority of recurrences become resistant to treatment. Once patients no longer respond to chemotherapy, there are minimal treatment options and they succumb to their disease. Therefore, there is a need to create new targeted therapies to overcome chemoresistance in ovarian cancer and improve patient survival. We have assembled a tumor microarray from 164 patient tumors to characterize the changes in protein expression that lead to resistance in clinical samples. We have found using IHC staining, that patients with high tyrosine kinase receptor discoidin domain receptor 2 (DDR2) protein expression (&gt;70%) have significantly shorter overall survival times regardless of stage at diagnosis (HR= 2.108, p=0.002) as well as reduced platinum free interval (p=0.046). Additionally, platinum refractory tumors have higher DDR2 protein expression than platinum sensitive tumors (p=0.036). To further understand the mechanisms of chemoresistance, we created a novel, chemoresistant, syngeneic, mouse ovarian cancer cell line derived from ID8 trp53-/-BRCA2-/- GFP LUC cells from Walton et. al 2016, and have designated them CHRP5. DDR2 expression assessed via western blot increased significantly in the chemoresistance cells, suggesting that DDR2 is associated with chemoresistance. We knocked down DDR2 using a stable shRNA transfection in CHRP5 and used MTS survival assays to determine if decreased DDR2 expression increases sensitivity to chemotherapy. CHRP5 shDDR2 cells were significantly more sensitive to carboplatin than CHRP5 shControl cells (CHRP5 shControl IC50=213.6uM, CHRP5 shDDR2 IC50=128.5uM, p&lt;0.000001), suggesting that DDR2 is involved in regulating chemoresistance in these cells. Additionally, we have submitted matched chemoresistant and chemosensitive mouse tumor samples for RNA-sequencing. We will use this data to determine which chemoresistant mechanisms are utilized, and if DDR2 is involved in regulating those mechanisms. In the future, we plan to rescue DDR2 in the knockdown cells to confirm that off target effects are not influencing the change in sensitivity. We also have access to a specific, allosteric inhibitor of DDR2 and plan to use this drug to determine if inhibiting DDR2 pharmacologically can overcome chemoresistance and reduce tumor burden in vivo and in vitro. In conclusion, DDR2 is more highly expressed in chemoresistant patients, and higher DDR2 expression correlates with reduced survival and platinum free interval. Additionally, knocking down DDR2 in chemoresistant cells increases sensitivity to chemotherapy. Therefore, DDR2 is a potential new target for ovarian cancer therapy and may be targeted to overcome chemoresistant disease and extend patient survival.

Citation Format: Alyssa Oplt, Elizabeth Stock, Hollie Noia, Patrick Cannon, Gregory Longmore, Katherine C. Fuh. The role of DDR2 in chemoresistant ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3235.

Abstract 163: Regulation of periostin by DDR2 in cancer-associated fibroblasts controls tumor invasion and metastasis in ovarian cancer

Ovarian cancer has the highest mortality of all gynecological malignancies. As such, there is a need to decipher molecular mechanisms that underlie tumor metastasis in ovarian cancer. Increased expression of receptor tyrosine kinase, DDR2, has been associated with worse patient survival. Identifying downstream targets of DDR2may allow specific modulation of ovarian cancer metastatic pathways with few off-target effects. Additionally, stromal cells play a critical role in metastasis. The crosstalk between tumor and stromal cells cans hift the balance between tumor progression or inhibition. We identified periostin to be highly expressed by fibroblasts expressing DDR2compared to fibroblasts without DDR2(Fold change=2.0, P=0.03).We show that DDR2regulates periostin in ovarian cancer associated fibroblast (CAFs). DDR2and periostin expression in the CAFs leads to512% increase in mesothelial cell clearance ratio(P=0.0004) and matrigel invasion(612vs 193invading cells/hpf, P&lt;0.0001). Mice injected withCAFs expressing periostin as well as ovarian cancer tumor cells have 72% increased tumor burden compared to mice with CAFs that do not express periostin (P=0.006). High periostin expression in CAFs leads to decreased T-cell proliferation and cytotoxicity. We validate periostin as a marker for patient outcome in ovarian cancer patients. Patients with high periostin expression have worse overall survival thant hose with low periostin expression. Mapping regulatory networks involved in tumor initiation and progression is important for identification of novel therapeutic targets.

Citation Format: Favour A. Akinjiyan, Ritu M. Dave, Katherine C. Fuh. Regulation of periostin by DDR2 in cancer-associated fibroblasts controls tumor invasion and metastasis in ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 163.

Impact of the COVID-19 pandemic on referral to and delivery of gynecologic oncology care

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The COVID-19 pandemic has significantly impacted gynecologic cancer care.

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Referrals to gynecologic oncology decreased in the early months of the pandemic.

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Referral time to gynecologic oncology evaluation was not impacted by the pandemic.

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Time to cancer treatment initiation decreased significantly during the pandemic.

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Disparities in time to cancer treatment initiation improving during the pandemic.

Objective

To evaluate the impact of the COVID-19 pandemic on referral to and delivery of gynecologic oncology care at a National Cancer Institute-designated Comprehensive Cancer Center.

Methods

We conducted a retrospective cohort study of patients referred for evaluation by a gynecologic oncologist at Washington University in St. Louis from October 2019 – February 2020 (pre-COVID-19), and April - August 2020 (COVID-19). The primary outcome, time from referral to evaluation by a gynecologic oncologist, was compared between the two time periods. Secondary outcomes included time from initial evaluation to treatment and delays/interruptions in care due to the pandemic. Sub-group analyses were performed on patients with a cancer diagnosis to evaluate the impact of COVID-19 on treatment decision making.

Results

884 patients were referred during the study period. Total referrals fell by 32% (526 to 358 patients, p < 0.001) and referrals for cancer fell by 18% (228 to 188 patients, p = 0.049). The pandemic did not impact time from referral to initial gynecologic oncology appointment overall (pre-COVID-19: 19.1 vs. COVID-19: 17.4 days, p = 0.315) or among patients with cancer (14.4 vs. 13.9 days, p = 0.662). Time from initial appointment to cancer treatment decreased by 9 days (34 days to 25 days, p = 0.001).

Conclusion

Referrals to gynecologic oncology decreased significantly during the early months of COVID-19. Though time from referral to evaluation was not impacted by the pandemic, time to treatment initiation decreased despite institutional changes related to COVID-19.

Inhibition of AXL and VEGF-A Has Improved Therapeutic Efficacy in Uterine Serous Cancer

Endometrial cancer remains the most prevalent gynecologic cancer with continued rising incidence. A less common form of this cancer is uterine serous cancer, which represents 10% of endometrial cancer cases. However, this is the most aggressive cancer. The objective was to assess whether inhibiting the receptor tyrosine kinase AXL with AVB-500 in combination with bevacizumab would improve response in uterine serous cancer. To prove this, we conducted multiple angiogenesis assays including tube formation assays and angiogenesis invasion assays. In addition, we utilized mouse models with multiple cells lines and subsequently analyzed harvested tissue through immunohistochemistry CD31 staining to assess microvessel density. The combination treatment arms demonstrated decreased angiogenic potential in each assay. In addition, intraperitoneal mouse models demonstrated a significant decrease in tumor burden in two cell lines. The combination of AVB-500 and bevacizumab reduced tumor burden in vivo and reduced morphogenesis and migration in vitro which are vital to the process of angiogenesis.

GAS6/AXL Inhibition Enhances Ovarian Cancer Sensitivity to Chemotherapy and PARP Inhibition through Increased DNA Damage and Enhanced Replication Stress

Over 80% of women with high-grade serous ovarian cancer (HGSOC) develop tumor resistance to chemotherapy and die of their disease. There are currently no FDA-approved agents to improve sensitivity to first-line platinum- and taxane-based chemotherapy or to PARP inhibitors. Here, we tested the hypothesis that expression of growth arrest-specific 6 (GAS6), the ligand of receptor tyrosine kinase AXL, is associated with chemotherapy response and that sequestration of GAS6 with AVB-S6-500 (AVB-500) could improve tumor response to chemotherapy and PARP inhibitors. We found that GAS6 levels in patient tumor and serum samples collected before chemotherapy correlated with ovarian cancer chemoresponse and patient survival. Compared with chemotherapy alone, AVB-500 plus carboplatin and/or paclitaxel led to decreased ovarian cancer-cell survival in vitro and tumor burden in vivo. Cells treated with AVB-500 plus carboplatin had more DNA damage, slower DNA replication fork progression, and fewer RAD51 foci than cells treated with carboplatin alone, indicating AVB-500 impaired homologous recombination (HR). Finally, treatment with the PARP inhibitor olaparib plus AVB-500 led to decreased ovarian cancer-cell survival in vitro and less tumor burden in vivo. Importantly, this effect was seen in HR-proficient and HR-deficient ovarian cancer cells. Collectively, our findings suggest that GAS6 levels could be used to predict response to carboplatin and AVB-500 could be used to treat platinum-resistant, HR-proficient HGSOC. IMPLICATIONS: GAS6/AXL is a novel target to sensitize ovarian cancers to carboplatin and olaparib. Additionally, GAS6 levels can be associated with response to carboplatin treatment.

Phase 1b study of AVB-500 in combination with paclitaxel or pegylated liposomal doxorubicin platinum-resistant recurrent ovarian cancer

OBJECTIVE

GAS6 and AXL are expressed in high-grade serous ovarian cancer but not in normal ovarian tissue. AVB-500, a novel high affinity Fc-sAXL fusion protein, binds GAS6 preventing AXL signaling. This Phase 1b study (NCT03639246) evaluated safety, efficacy, and exploratory predictive markers of AVB-500 combined with paclitaxel (PAC) or pegylated liposomal doxorubicin (PLD) in patients with platinum-resistant ovarian cancer (PROC), and used a model informed drug development (MIDD) approach for identification of the recommended phase 2 dose (RP2D).

METHODS

Eligible patients received AVB-500 at 10, 15, or 20 mg/kg IV q2wk combined with PAC (n = 23) or PLD (n = 30). Patients were treated until progression or unacceptable toxicity. All were followed for survival.

RESULTS

No dose limiting toxicities were observed and serum GAS6 was completely suppressed across the three dose levels evaluated. AVB-500 + PAC yielded better clinical activity than AVB-500 + PLD with an ORR of 34.8% (8/23, 2 complete responses) and median DoR, PFS, and OS of 7.0, 3.1, and 10.3 months, respectively. Subgroup analyses showed AVB-500 + PAC patients who had no prior bevacizumab or whose AVB-500 trough levels were >13.8 mg/L exhibited the best clinical response. The ORR and median PFS and OS in patients with these characteristics were ≥50%, ≥7.5 months, and ≥19 months, respectively. Given AVB-500 nor the combination with chemotherapy was expected to cause DLTs, the RP2D of AVB-500 was 15 mg/kg identified using an MIDD approach.

CONCLUSION

AVB-500 was well-tolerated in combination with PAC or PLD and contributed to the clinical activity of PAC in PROC patients. Subgroup analyses identified a population of PROC patients who may benefit the most from AVB-500 treatment, which will be further assessed in an ongoing Phase 3 PROC trial.

Comprehensive characterization of 536 patient-derived xenograft models prioritizes candidatesfor targeted treatment

Development of candidate cancer treatments is a resource-intensive process, with the research community continuing to investigate options beyond static genomic characterization. Toward this goal, we have established the genomic landscapes of 536 patient-derived xenograft (PDX) models across 25 cancer types, together with mutation, copy number, fusion, transcriptomic profiles, and NCI-MATCH arms. Compared with human tumors, PDXs typically have higher purity and fit to investigate dynamic driver events and molecular properties via multiple time points from same case PDXs. Here, we report on dynamic genomic landscapes and pharmacogenomic associations, including associations between activating oncogenic events and drugs, correlations between whole-genome duplications and subclone events, and the potential PDX models for NCI-MATCH trials. Lastly, we provide a web portal having comprehensive pan-cancer PDX genomic profiles and source code to facilitate identification of more druggable events and further insights into PDXs' recapitulation of human tumors.

Cancer-associated mesothelial cells promote ovarian cancer chemoresistance through paracrine osteopontin signaling

Ovarian cancer is the leading cause of gynecological malignancy-related deaths, due to its widespread intraperitoneal metastases and acquired chemoresistance. Mesothelial cells are an important cellular component of the ovarian cancer microenvironment that promote metastasis. However, their role in chemoresistance is unclear. Here, we investigated whether cancer-associated mesothelial cells promote ovarian cancer chemoresistance and stemness in vitro and in vivo. We found that osteopontin is a key secreted factor that drives mesothelial-mediated ovarian cancer chemoresistance and stemness. Osteopontin is a secreted glycoprotein that is clinically associated with poor prognosis and chemoresistance in ovarian cancer. Mechanistically, ovarian cancer cells induced osteopontin expression and secretion by mesothelial cells through TGF-β signaling. Osteopontin facilitated ovarian cancer cell chemoresistance via the activation of the CD44 receptor, PI3K/AKT signaling, and ABC drug efflux transporter activity. Importantly, therapeutic inhibition of osteopontin markedly improved the efficacy of cisplatin in both human and mouse ovarian tumor xenografts. Collectively, our results highlight mesothelial cells as a key driver of ovarian cancer chemoresistance and suggest that therapeutic targeting of osteopontin may be an effective strategy for enhancing platinum sensitivity in ovarian cancer.

Abstract 2202: Genetic characterization of metastasis and prognosis in high-grade serous ovarian cancer

High-grade serous ovarian cancer (HGSC) is the most lethal histotype of ovarian cancer and is highly prone to metastasis, with the majority of patients presenting at advanced stages of disease. There are few targeted treatment options for HGSC patients, especially for women with high metastatic tumor burdens. In order to identify potential genetic targets in metastatic disease, we characterized the genomic and transcriptomic alterations of metastatic tumors in HGSC patients. In this study, matched normal tissue, primary, and metastatic tumors from 23 HGSC short-term (ST) survivors (overall survival [OS] &lt;3.5 years) and 14 long-term (LT) survivors (OS &gt;5 years) underwent whole exome and RNA sequencing. We compared somatic mutations, copy number alternations, mutational burdens, differential expression, immune cell fractions, and gene fusion predictions between the primary and metastatic tumors of the ST and LT survival groups.

We confirmed that tumors of LT survivors were more likely to have BRCA1 alterations and more copy-altered segments when compared to tumors of ST survivors. There was a higher percentage of shared variants between the primary and metastatic tumors for ST survivors compared to LT survivors. ST survivors also had a greater mutational burden and more predicted gene fusions than LT. We observed few differentially expressed genes between primary and metastatic tumors, but we did observe significant differences between the transcriptomes of LT and ST survivors' tumors. Overall, we observed that HGSC primary and metastatic tumors had similar genomic and transcriptomic landscapes, but we identified genetic characteristics specific to metastatic tumors that correlate with survival.

Citation Format: Emilee N. Kotnik, Nicholas C. Spies, Tiandao Li, Matthew Inkman, Jin Zhang, Fernanda Martins-Rodrigues, Ian S. Hagemann, Carolyn K. McCourt, Premal H. Thaker, Andrea R. Hagemann, Matthew A. Powell, David G. Mutch, Christopher A. Maher, Christopher A. Miller, Katherine C. Fuh. Genetic characterization of metastasis and prognosis in high-grade serous ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2202.

Text-message-based behavioral weight loss for endometrial cancer survivors with obesity: A randomized controlled trial

OBJECTIVE

To evaluate the ability of a personalized text-message-based intervention to increase weight loss among endometrial cancer survivors with obesity.

METHODS

In this randomized, controlled trial, endometrial cancer survivors with obesity (BMI ≥30 kg/m²) were randomized to a personalized SMS text-message-based weight loss intervention or enhanced usual care. Primary outcome was weight loss at 6 months; secondary outcomes were weight loss at 12 months and changes in psychosocial measures. We also compared clinical characteristics and weight change between trial participants and non-participants.

RESULTS

Between May 18 and December 31, 2017, 80 endometrial cancer survivors with obesity consented to participate in the randomized trial. There were no differences in clinical characteristics between the two arms. Weight changes were similar in the two arms (P = 0.08). At 6 months, no differences in quality of life, physical activity, or body image were noted. Of 358 eligible patients, 80 became trial participants and 278, non-participants. Trial participants were younger (59.3 vs. 63.4 years, P < 0.001), more likely non-white (P = 0.02), on fewer medications (4 vs. 7, P < 0.001), and had a higher median BMI (38.7 vs. 37.6 kg/m², P = 0.01) than non-participants. Weight change was similar between participants and non-participants (P = 0.85). At 6 months, similar percentages of participants and non-participants (47.7% vs. 44.4%) had gained weight, and similar percentages (9.2% vs. 11.2%) had lost at least 5% of their body weight.

CONCLUSIONS

This text-message-based intervention did not increase weight loss among endometrial cancer survivors with obesity, nor did participation in the trial. Other weight management interventions should be promoted to increase weight loss.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, www.clinicaltrials.gov, NCT03169023.

Radiation therapy for vaginal and perirectal lesions in recurrent ovarian cancer

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Radiation to isolated vaginal and perirectal ovarian cancer recurrences provides effective in-field control.

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Complete response of targeted lesions after radiation was 88%.

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Radiation increased the chemotherapy-free interval without associated grade 3/4 toxicities.

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Platinum sensitivity prior to radiation may be associated with improved overall survival.

The role for localized radiation to treat ovarian cancer (OC) patients with locally recurrent vaginal/perirectal lesions remains unclear, though we hypothesize these patients may be salvaged locally and gain long-term survival benefit. We describe our institutional outcomes using intensity modulated radiation therapy (IMRT) +/- high-dose rate (HDR) brachytherapy to treat this population. Our primary objectives were to evaluate complete response rates of targeted lesions after radiation and calculate our 5-year in-field control (IFC) rate. Secondary objectives were to assess radiation-related toxicities, chemotherapy free-interval (CFI), as well as post-radiation progression-free (PFS) and overall survival (OS). PFS and OS were defined from radiation start to either progression or death/last follow-up, respectively. This was a heavily pre-treated cohort of 17 recurrent OC patients with a median follow-up of 28.4 months (range 4.5–166.4) after radiation completion. 52.9% had high-grade serous histology and 4 (23.5%) had isolated vaginal/perirectal disease. Four (23.5%) patients had in-field failures at 3.7, 11.2, 24.5, and 27.5 months after start of radiation, all treated with definitive dosing of radiation therapy. Patients who were platinum-sensitive prior to radiation had similar median PFS (6.5 vs. 13.4 months, log-rank p = 0.75), but longer OS (71.1 vs 18.8 months, log-rank p = 0.05) than their platinum-resistant counterparts. Excluding patients with low-grade histology or who were treated with palliative radiation, median CFI was 14.2 months (range 4.7 – 33.0). Radiation was well tolerated with 2 (12.0%) experiencing grade 3/4 gastrointestinal/genitourinary toxicities. In conclusion, radiation to treat locally recurrent vaginal/perirectal lesions in heavily pre-treated OC patients is safe and may effectively provide IFC.

Entinostat, a selective HDAC1/2 inhibitor, potentiates the effects of olaparib in homologous recombination proficient ovarian cancer

OBJECTIVE

Poly ADP ribose polymerase inhibitors (PARPi) are most effective in BRCA1/2 mutated ovarian tumors. Better treatments are needed for homologous recombination HR-proficient cancer, including CCNE1 amplified subtypes. We have shown that histone deacetylase inhibitors (HDACi) sensitize HR-proficient ovarian cancer to PARPi. In this study, we provide complementary preclinical data for an investigator-initiated phase 1/2 clinical trial of the combination of olaparib and entinostat in recurrent, HR-proficient ovarian cancer.

METHODS

We assessed the in vitro effects of the combination of olaparib and entinostat in SKOV-3, OVCAR-3 and primary cells derived from CCNE1 amplified high grade serous ovarian cancer (HGSOC) patients. We then tested the combination in a SKOV-3 xenograft model and in a patient-derived xenograft (PDX) model.

RESULTS

Entinostat potentiates the effect of olaparib in reducing cell viability and clonogenicity of HR-proficient ovarian cancer cells. The combination reduces peritoneal metastases in a SKOV-3 xenograft model and prolongs survival in a CCNE1 amplified HR-proficient PDX model. Entinostat also enhances olaparib-induced DNA damage. Further, entinostat decreases BRCA1, a key HR repair protein, associated with decreased Ki-67, a proliferation marker, and increased cleaved PARP, a marker of apoptosis. Finally, entinostat perturbs replication fork progression, which increases genome instability.

CONCLUSION

Entinostat inhibits HR repair by reducing BRCA1 expression and stalling replication fork progression, leading to irreparable DNA damage and ultimate cell death. This work provides preclinical support for the clinical trial of the combination of olaparib and entinostat in HR-proficient ovarian cancer and suggests potential benefit even for CCNE1 amplified subtypes.

A deficit-accumulation frailty index predicts survival outcomes in patients with gynecologic malignancy

OBJECTIVE

To determine the association between scores from a 25-item patient-reported Rockwood Accumulation of Deficits Frailty Index (DAFI) and survival outcomes in gynecologic cancer patients.

METHODS

A frailty index was constructed from the SEER-MHOS database. The DAFI was applied to women age ≥ 65 diagnosed with all types of gynecologic cancers between 1998 and 2015. The impact of frailty status at cancer diagnosis on overall survival (OS) was analyzed using Kaplan-Meier curves and Cox proportional hazards regression.

RESULTS

In this cohort (n = 1336) the median age at diagnosis was 74 (range 65-97). Nine hundred sixty-two (72%) women were Caucasian and 132 (10%) were African-American. Overall, 651(49%) of patients were considered frail. On multivariate analysis, frail patients had a 48% increased risk for death (aHR 1.48; 95% CI 1.29-1.69; P < 0.0001). Each 10% increase in frailty index was associated with a 16% increased risk of death (aHR, 1.16; 95% CI, 1.11 to 1.21; P < 0.0001). In subgroup analyses of the varying cancer types, the association of frailty status with prognosis was fairly consistent (aHR 1.15-2.24). The DAFI was more prognostic in endometrial (aHR 1.76; 95% CI 1.41-2.18, P < 0.0001) and vaginal/vulvar (aHR 1.94; 95% CI 1.34-2.81, P = 0.0005) cancers as well as patients with loco-regional disease (aHR 1.94; 95% CI 1.62-2.33, P < 0.0001).

CONCLUSIONS

Frailty appears to be a significant predictor of mortality in gynecologic cancer patients regardless of chronological age. This measure of functional age may be of particular utility in women with loco-regional disease only who otherwise would have a favorable prognosis.

Obese endometrial cancer survivors' perceptions of weight loss strategies and characteristics that may influence participation in behavioral interventions

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Endometrial cancer (EC) survivors have attempted many methods to lose weight.

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EC survivors rarely choose bariatric surgery, physical therapy, or psychologic support services to lose weight.

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EC survivors without recurrence were more likely to enroll in a weight loss intervention trial than those with recurrence.

We aimed to evaluate obese endometrial cancer (EC) survivors' perceptions of weight loss barriers and previously attempted weight loss methods and to identify characteristics that predicted willingness to enroll in a behavioral intervention trial. We administered a 27-question baseline survey at an academic institution to EC survivors with body mass index ≥ 30 kg/m². Survivors were asked about their lifestyles, previous weight loss attempts, perceived barriers, and were offered enrollment into an intervention trial. Data was analyzed using Fisher’s Exact, Kruskal-Wallis, and univariate and multivariate regressions. 155 of 358 (43%) eligible obese EC survivors were surveyed. Nearly all (n = 148, 96%) had considered losing weight, and 77% (n = 120) had tried two or more strategies. Few had undergone bariatric surgery (n = 5, 3%), psychologic counseling (n = 2, 1%), or met with physical therapists (n = 9, 6%). Lower income was associated with difficulty in accessing interventions. Survivors commented that negative self-perceptions and difficulties with follow-through were barriers to weight loss, and fear of complications and self-perceived lack of qualification were deterrents to bariatric surgery. 80 (52%) of those surveyed enrolled in the trial. In a multivariate model, adjusting for race and stage, survivors without recurrence were 4.3 times more likely to enroll than those with recurrence. Most obese EC survivors have tried multiple strategies to lose weight, but remain interested in weight loss interventions, especially women who have never experienced recurrence. Providers should encourage weight loss interventions early, at the time of initial diagnosis, and promote underutilized strategies such as psychological counseling, physical therapy, and bariatric surgery.

Impact of employment and insurance status on distress in gynecologic oncology patients

OBJECTIVES

To study associations among employment, insurance status, and distress in gynecologic oncology patients; and to evaluate the impact of being unemployed or having no/Medicaid insurance on different distress problem areas.

METHODS

In this single institution, cross-sectional analysis of gynecologic oncology patients, we screened for distress and problem areas using the National Comprehensive Cancer Network distress thermometer and problem list at outpatient appointments between 6/2017-9/2017. Primary outcome was self-reported high distress (score ≥ 5). The distress problem list included 5 categories-practical, family, emotional, physical, and other. Employment status included employed, unemployed, homemaker, and retired. Logistic regression was used to predict high distress from employment and insurance statuses, adjusting for relevant covariates.

RESULTS

Of 885 women, 101 (11.4%) were unemployed, and 53 (6.0%) uninsured or had Medicaid coverage. One in five patients (n = 191, 21.6%) indicated high distress. Unemployed patients were more likely than employed to endorse high distress [adjusted odds ratio (aOR) = 3.5, 95% confidence interval (CI) 2.2-5.7, p < 0.001]. Compared to employed patients, a greater proportion of unemployed patients endorsed distress related to practical (p < 0.05), emotional (p < 0.001), physical (p < 0.01), and other (p < 0.05) problems. Uninsured/Medicaid patients were more likely to endorse high distress (aOR = 2.8, 95% CI 1.5-5.1, p < 0.001) and report family (p < 0.001), emotional (p < 0.001), and other (p < 0.01) problems than patients who had Medicare/commercial insurance.

CONCLUSIONS

Gynecologic oncology patients who are unemployed or have no/Medicaid insurance face high distress that appears to arise from issues beyond practical problems, including financial and/or insurance insecurities.

Detection of a somatic GREB1-NCOA1 gene fusion in a uterine tumor resembling ovarian sex cord tumor (UTROSCT)

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Uterine tumor resembling ovarian sex cord tumor is a rare mesenchymal neoplasm.

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UTROSCT harbors recurrent rearrangements between NCOA1-3 and ESR1 or GREB1.

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RNA-sequencing can identify these rearrangements to support the diagnosis.

Uterine tumor resembling ovarian sex cord tumor (UTROSCT) is a rare uterine neoplasm of uncertain malignant potential. We present the case of a 69-year-old woman who underwent hysterectomy for postmenopausal bleeding and was found to have a myometrial UTROSCT. RNA-sequencing identified a somatic GREB1–NCOA1 fusion, supporting the diagnosis. Next-generation sequencing is increasingly being adopted in diagnostic pathology laboratories. This report highlights the value of RNA-sequencing in identifying rare fusion events to support pathologic diagnoses.

A fellow-run clinic achieves similar patient outcomes as faculty clinics: A safe and feasible model for gynecologic oncology fellow education

OBJECTIVES

Fellow involvement in patient care is important for education, but effect on patient care is unclear. Our aim was to compare patient outcomes in gynecologic oncology attending clinics versus a fellow training clinic at a large academic medical center.

METHODS

A retrospective review of consecutive gynecologic oncology patients from six attending clinics and one faculty-supervised fellow clinic was used to analyze differences based on patient demographics, cancer characteristics, and practice patterns. Primary outcome was overall survival (OS); secondary outcomes included recurrence-free survival (RFS), postoperative complications and chemotherapy within the last 30 days of life. Survival analyses were performed using Kaplan-Meier curves with log-rank tests.

RESULTS

Of 159 patients, 76 received care in the attending clinic and 83 in the fellow clinic. Patients in the fellow clinic were younger, less likely to be Caucasian, and more overweight, but cancer site and proportion of advanced stage disease were similar. Both clinics had similar rates of moderate to severe adverse events related to surgery (15% vs. 8%, p = .76), chemotherapy (21% vs. 23%, p = .40), and radiation (14% vs. 17%, p = .73). There was no difference in median RFS in the fellow compared to attending clinic (38 vs. 47 months, p = .78). OS on both univariate (49 months-fellow clinic, 60 months-attending clinic vs. p = .40) and multivariate analysis [hazard ratio 1.3 (0.57, 2.75), P = .58] was not significantly different between groups.

CONCLUSIONS

A fellow-run gynecologic oncology clinic designed to provide learning opportunities does not compromise patient outcomes and is a safe and feasible option for fellow education.

Abstract A17: Characterization of primary-metastasis pairs in high-grade serous ovarian cancer with short- and long-term survival

High-grade serous ovarian cancer (HGSC) is a highly metastatic cancer with the majority of patients presenting at advanced stages. Over the last few decades, the overall survival and standard of care for patients have not significantly improved and there are limited targeted treatment options for patients. Although we have learned much about the genomic characteristics of HGSC primary tumors, there has been a lack of characterization of metastatic tumors. In order to identify genetic markers of metastasis and poor prognosis, we have characterized the genomic and transcriptomic alterations of primary and metastatic tumors in HGSC patients with different survival outcomes. In this study, matched normal tissue, primary, and metastatic tumors from 23 HGSC short-term (ST) survivors (OS &lt;3.5 years) and 14 long-term (LT) survivors (OS &gt;5 years) underwent whole-exome and RNA sequencing. We compared somatic mutations, copy number alternations, mutational burdens, differential expression, homologous recombination (HRD) scores, and gene fusion predictions between the primary and metastatic tumors of the ST and LT survival groups. We confirmed previously published findings that tumors of LT survivors were more likely to have BRCA1 alterations, higher HRD scores, and more copy-altered segments when compared to tumors of ST survivors. We identified 10,124 somatic mutations in the tumors of LT survivors and 13,599 somatic mutations in ST survivors. There was a higher percentage of shared variants between the primary and metastatic tumors for ST survivors compared to LT survivors. ST survivors also had a greater mutational burden than LT survivors. We observed little differences in differential expression between primary and metastatic tumors, but we did observe unique clustering between the transcriptomes of LT and ST survivors’ tumors. Although there was no significant difference between the number of gene fusions predicted between primary and metastatic tumors, there was a total of 1,218 gene fusions predicted in ST survivors’ tumors, which was significantly more than the 240 gene fusions predicted in LT survivors. The ST primary tumor group had the highest number of predicted gene fusions. Interestingly, we observed that patients with HRD-positive primary tumors but HRD-negative metastatic tumors had significantly shorter overall survival compared to matched tumor pairs with no, or very little, difference in HRD scores. This finding suggests that differences in HRD scores between primary and metastatic tumors in HGSC patients may correlate with survival. Overall, we observed similar genomic and transcriptomic findings in the landscape between primary and metastatic tumors in HGSC patients and identified genetic characteristics specific to tumors of LT and ST survivors.

Citation Format: Emilee N. Kotnik, Nicholas C. Spies, Christopher A. Miller, Tiandao Li, Matthew Inkman, Jin Zhang, Christopher A. Maher, Carolyn K. McCourt, Premal H. Thaker, Andrea R. Hagemann, David G. Mutch, Matthew A. Powell, Katherine C. Fuh. Characterization of primary-metastasis pairs in high-grade serous ovarian cancer with short- and long-term survival [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 A17.

Abstract TMIM-081: THE HYPOXIC TUMOR-MESOTHELIAL NICHE PROMOTES OVARIAN CANCER METASTASIS THROUGH COLLAGEN REMODELING

High grade serous ovarian cancer (HGSOC) is a leading cause of cancer related deaths among women. The primary cause of morbidity and mortality in HGSOC patients is metastasis to organs within the peritoneal cavity. Mesothelial cells line the surface of peritoneal organs and are a key stromal cell in HGSOC metastatic niche. However, the mechanisms by which mesothelial cells promote ovarian cancer peritoneal metastasis remain largely unknown. Here we demonstrate that tumor associated mesothelial cells promote tumor invasion by increasing collagen deposition and remodeling. Mechanistically, we demonstrate the tumor-mesothelial niche is hypoxic where both tumor cells and mesothelial cells express the hypoxia inducible factors HIF-1 and HIF-2 and their downstream target gene lysyl oxidase (LOX). LOX is an enzyme that crosslinks collagen fibrils to promote collagen remodeling. In tumor-mesothelial co-culture experiments, we demonstrate that hypoxia enhances extracellular fibrillar collagen deposition by mesothelial cells. Conditioned media from hypoxic tumor-mesothelial co-cultures promotes collagen remodeling and HGSOC tumor cell invasion. Genetic inactivation of either HIF-1 and HIF-2 or LOX reduces the hypoxic induction of collagen remodeling and tumor cell invasion. Importantly, pharmacologic inhibition of HIF-1 and HIF-2 with digoxin reduces the colonization of disseminated HGSOC cells to the omentum, the preferential migration site of peritoneal cancer metastasis. Moreover, pharmacologic inhibition of LOX with BAPN (beta-aminopropionitrile) is sufficient to inhibit metastatic tumor burden and collagen remodeling at metastatic sites in preclinical models of HGSOC metastasis. These data reveal a novel role for mesothelial cells in the production of type I collagen and collagen remodeling in the HGSOC metastatic microenvironment. Furthermore, these studies demonstrate a role for the HIF/LOX signaling axis in the HGSOC tumor-mesothelial niche that can be therapeutically targeted to inhibit collagen remodeling and ovarian cancer metastatic progression.

Citation Format: Suchitra Natarajan, Katie Foreman, Michaela Soriano, Hussein Shehade, Daniel Fregoso, Joshua Eggold, Ninna S. Rosen, Sarah Heilshorn, Adam J. Krieg, Venkatesh Krishnan, Oliver Dorigo, Subarna Sinha, Katherine C. Fuh, Erinn B. Rankin. THE HYPOXIC TUMOR-MESOTHELIAL NICHE PROMOTES OVARIAN CANCER METASTASIS THROUGH COLLAGEN REMODELING [abstract]. In: Proceedings of the 12th Biennial Ovarian Cancer Research Symposium; Sep 13-15, 2018; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2019;25(22 Suppl):Abstract nr TMIM-081.

S100A10 Is a Critical Mediator of GAS6/AXL-Induced Angiogenesis in Renal Cell Carcinoma

Angiogenesis is a hallmark of cancer that promotes tumor progression and metastasis. However, antiangiogenic agents have limited efficacy in cancer therapy due to the development of resistance. In clear cell renal cell carcinoma (ccRCC), AXL expression is associated with antiangiogenic resistance and poor survival. Here, we establish a role for GAS6/AXL signaling in promoting the angiogenic potential of ccRCC cells through the regulation of the plasminogen receptor S100A10. Genetic and therapeutic inhibition of AXL signaling in ccRCC tumor xenografts reduced tumor vessel density and growth under the renal capsule. GAS6/AXL signaling activated the expression of S100A10 through SRC to promote plasmin production, endothelial cell invasion, and angiogenesis. Importantly, treatment with the small molecule AXL inhibitor cabozantinib or an ultra-high affinity soluble AXL Fc fusion decoy receptor (sAXL) reduced the growth of a pazopanib-resistant ccRCC patient-derived xenograft. Moreover, the combination of sAXL synergized with pazopanib and axitinib to reduce ccRCC patient-derived xenograft growth and vessel density. These findings highlight a role for AXL/S100A10 signaling in mediating the angiogenic potential of ccRCC cells and support the combination of AXL inhibitors with antiangiogenic agents for advanced ccRCC. SIGNIFICANCE: These findings show that angiogenesis in renal cell carcinoma (RCC) is regulated through AXL/S100A10 signaling and support the combination of AXL inhibitors with antiangiogenic agents for the treatment of RCC.

Differences in presentation and survival of Asians compared to Caucasians with ovarian cancer: An NRG Oncology/GOG Ancillary study of 7914 patients

PURPOSE

To compare patient/tumor characteristics and outcomes of Asians to Caucasian patients with epithelial ovarian cancer.

METHODS

Ancillary data were pooled and analyzed from ten prospective randomized front-line Gynecologic Oncology Group clinical trials from 1996 to 2011. Demographic, clinicopathologic features, disease-specific and all-cause survival were analyzed.

RESULTS

Of 7914 patients, 7641 were Caucasian and 273 Asian. When compared to Caucasians, Asians were younger at trial enrollment, had a better performance status, earlier-stage cancers (17.2% vs. 8.1% with stage I; p < 0.001), and were more likely to be of clear cell (15.8% vs. 6.2%, p < 0.001) and mucinous (3.3% vs. 1.9%, p < 0.001) histology. Asians had an improved 5-year disease-specific survival of 54.1% compared to 46.1% for Caucasians, p = 0.001. In multivariate analysis, the Asian race remained a significant prognostic factor for all-cause survival (HR: 0.84; 95% CI: 0.72-0.99; p = 0.04). Other factors predictive of improved survival included younger age, better performance status, optimal cytoreduction, earlier stage, non-clear cell histology, and lower grade tumors.

CONCLUSION

Asians enrolled into phase III ovarian cancer clinical trials were younger, with better performance status, earlier-stage of disease, and have a greater number of clear cell and mucinous tumors. After adjusting for these prognostic factors, Asians have a better survival compared to Caucasians.

Type II endometrial cancers with minimal, non-invasive residual disease on final pathology: What should we do next?

There are minimal data regarding the management of high risk endometrial cancer histologies lacking invasive disease on the final pathology specimen. This study examines a cohort of these patients and assesses outcomes including time to recurrence and risk of death after management with and without adjuvant therapies.

Endometrial cancer patients with minimal or no remaining invasive disease on final pathologic specimen from 1995 to 2010 were included. Surgical procedure was at the discretion of the operating physician. Electronic medical records were used to abstract relevant clinicopathologic data and standard statistical methods were employed.

70 patients met inclusion criteria, of which 26 were high grade histologies. Adjuvant therapies were given in 12 of 26 patients. 6/26 patients recurred, of which 50% were salvaged with therapy at time of recurrence. Overall deaths occurred in 3 of 26 patients in the high risk cohort.

Less than half of the high risk cohort received adjuvant therapies after surgical management. No histologic type was found to increase risk of recurrence, and treatment with initial adjuvant therapy did not significantly reduce recurrence risk. Large scale prospective trials are needed to aid in management of this unique endometrial cancer population.

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This series describes a cohort of high risk with minimal remaining disease on final pathology specimen.

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Patients with clear cell histology who went on to recur did so quickly and were salvageable.

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Treatment with adjuvant therapy after primary surgery did not significantly improve risk of recurrence.

Do gynecologic oncology patients with severely diminished renal function and urinary tract obstruction benefit from ureteral stenting or percutaneous nephrostomy?

Objective

To assess the renal outcomes of gynecologic oncology patients who present with hydronephrosis and acute kidney injury (AKI), have <20% renal function on diuretic renal scintigraphy, and undergo placement of a ureteral stent or percutaneous nephrostomy (PCN) tube.

Methods

This is a single-institution case series of gynecologic oncology patients who underwent diuretic renal scintigraphy from January 1, 2007, to June 1, 2017. Univariate and multivariate logistic analyses were used to assess predictors of <20% renal function. Recovery from AKI or elevated creatinine was reported for women with <20% renal function who received a unilateral ureteral stent or PCN tube on the same side as their more compromised kidney.

Results

Among 353 gynecologic oncology patients who underwent diuretic renal scintigraphy, 58 (16%) had renal function <20%. Mean age was 59.6 years, 17% had preexisting chronic kidney disease, and 44% had a diagnosis of cervical cancer. Renal atrophy on computed tomography scan (aOR 18.24, 95% CI 1.21–274.92) predicted renal function <20%. Of 10 women with <20% renal function who received a stent or PCN tube, 7 recovered from AKI or elevated creatinine.

Conclusions

Gynecologic oncology patients with <20% renal function may recover from AKI after placement of a stent or PCN tube, indicating that a diuretic renal scintigraphy cutoff of <20% renal function may be overly conservative. Future studies are warranted to determine optimal renal function cutoffs for stent/PCN tube placement in gynecologic oncology patients.

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Renal atrophy on CT scan is an independent predictor of severely compromised renal function.

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Gynecologic oncology patients with <20% renal function may recover from AKI after placement of a stent or PCN tube.

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<20% relative renal function on diuretic renal scintigraphy may be an overly conservative cutoff for kidney salvageability.

p5RHH nanoparticle-mediated delivery of AXL siRNA inhibits metastasis of ovarian and uterine cancer cells in mouse xenografts

Ovarian and uterine serous cancers are extremely lethal diseases that often present at an advanced stage. The late-stage diagnosis of these patients results in the metastasis of their cancers throughout the peritoneal cavity leading to death. Improving survival for these patients will require identifying therapeutic targets, strategies to target them, and means to deliver therapies to the tumors. One therapeutic target is the protein AXL, which has been shown to be involved in metastasis in both ovarian and uterine cancer. An effective way to target AXL is to silence its expression with small interfering RNA (siRNA). We investigate the ability of the novel siRNA delivery platform, p5RHH, to deliver anti-AXL siRNA (siAXL) to tumor cells both in vitro and in vivo as well as examine the phenotypic effects of this siRNA interference. First, we present in vitro assays showing p5RHH-siAXL treatment reduces invasion and migration ability of ovarian and uterine cancer cells. Second, we show p5RHH nanoparticles target to tumor cells in vivo. Finally, we demonstrate p5RHH-siAXL treatment reduces metastasis in a uterine cancer mouse xenograft model, without causing an obvious toxicity. Collectively, these findings suggest that this novel therapy shows promise in the treatment of ovarian and uterine cancer patients.

Collagen Remodeling in the Hypoxic Tumor-Mesothelial Niche Promotes Ovarian Cancer Metastasis

Peritoneal metastases are the leading cause of morbidity and mortality in high-grade serous ovarian cancer (HGSOC). Accumulating evidence suggests that mesothelial cells are an important component of the metastatic microenvironment in HGSOC. However, the mechanisms by which mesothelial cells promote metastasis are unclear. Here, we report that the HGSOC tumor-mesothelial niche was hypoxic, and hypoxic signaling enhanced collagen I deposition by mesothelial cells. Specifically, hypoxic signaling increased expression of lysyl oxidase (LOX) in mesothelial and ovarian cancer cells to promote collagen crosslinking and tumor cell invasion. The mesothelial niche was enriched with fibrillar collagen in human and murine omental metastases. Pharmacologic inhibition of LOX reduced tumor burden and collagen remodeling in murine omental metastases. These findings highlight an important role for hypoxia and mesothelial cells in the modification of the extracellular matrix and tumor invasion in HGSOC. SIGNIFICANCE: This study identifies HIF/LOX signaling as a potential therapeutic target to inhibit collagen remodeling and tumor progression in HGSOC.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/79/9/2271/F1.large.jpg.

Association between body mass index and surgical menopausal symptoms in patients with early stage endometrial cancer

OBJECTIVES

Premenopausal women may undergo surgical menopause after staging for their endometrial cancer. Our aim was to determine the association between body mass index (BMI) and surgical menopausal symptoms.

METHODS

We report a retrospective review of endometrial cancer patients whom underwent menopause secondary to their surgical staging procedure. Symptoms were classified as severe if treatment was prescribed, or mild if treatment was offered, but declined. Univariate analysis was performed with ANOVA and Chi-square tests as appropriate. Relative risks (RR) were generated from Poisson regression models.

RESULTS

We identified 166 patients in whom the BMI (kg/m²) distribution was as follows: 33 (19.9%) had BMI <30, 49 (29.5%) had BMI 30-39.9, 50 (30.1%) had BMI 40-49.9, and 34 (20.5%) had BMI ≥50. There were no differences in race, age, or adjuvant treatment among the groups. Overall, 65 (39.2%) women reported symptoms of surgical menopause, including 19 (11.4%) mild and 46 (27.7%) severe. Symptom type did not differ by BMI; however, the prevalence of severe menopausal symptoms decreased with increasing BMI: <30 (45.5%), 30-39.9 (30.6%), 40-49.9 (22%), and ≥ 50 (14.7%); P = 0.002. Multivariate analysis confirmed that symptom prevalence decreased with increasing BMI. Compared to women with a BMI of <30, those with a BMI 40-49.9 (RR = 0.39, 95% CI: 0.17-0.87) or ≥ 50 (RR = 0.24, 95% CI: 0.08-0.70) were significantly less likely to experience menopausal symptoms.

CONCLUSIONS

Women younger than 50 with BMI >40 and stage I endometrial cancer are significantly less likely than women with BMI <30 to experience menopausal symptoms after oophorectomy. This information may assist in peri-operative counseling.

Therapeutic Inhibition of the Receptor Tyrosine Kinase AXL Improves Sensitivity to Platinum and Taxane in Ovarian Cancer

Ovarian cancer, one of the deadliest malignancies in female cancer patients, is characterized by recurrence and poor response to cytotoxic chemotherapies. Fewer than 30% of patients with resistant disease will respond to additional chemotherapy treatments. This study aims to determine whether and how inhibition of the receptor tyrosine kinase AXL can restore sensitivity to first-line platinum and taxane therapy in ovarian cancer. AXL staining was quantified in a patient tissue microarray and correlated with chemoresponse of patients. We used small hairpin RNAs to knock down AXL expression and the small-molecule inhibitor BGB324 to inhibit AXL and assessed sensitivity of cell lines and primary patient-derived cells to chemotherapy. We quantified platinum accumulation by inductivity-coupled plasma phase mass spectrometry. Finally, we treated chemoresistant patient-derived xenografts with chemotherapy, BGB324, or chemotherapy plus BGB324 and monitored tumor burden. AXL expression was higher in chemoresistant patient tumors and cell lines than in chemosensitive tumors and cell lines. AXL staining significantly predicted chemoresponse. Knockdown and inhibition of AXL dose-dependently improved response to paclitaxel and carboplatin in both cell lines and primary cells. AXL inhibition increased platinum accumulation by 2-fold (*, P < 0.05). In vivo studies indicated that AXL inhibition enhanced the ability of chemotherapy to prevent tumor growth (****, P < 0.0001). AXL contributes to platinum and taxane resistance in ovarian cancer, and inhibition of AXL improves chemoresponse and accumulation of chemotherapy drugs. This study supports continued investigation into AXL as a clinical target.

SQ1274, a novel microtubule inhibitor, inhibits ovarian and uterine cancer cell growth

OBJECTIVE

Paclitaxel, a microtubule inhibitor, is subject to tumor resistance while treating high-grade serous ovarian and uterine cancer. This study aims to directly compare the effects of SQ1274, a novel microtubule inhibitor that binds to the colchicine-binding site on tubulin, and paclitaxel in high-grade serous ovarian and uterine cancer cell lines both in vitro and in vivo.

METHODS

We assessed the sensitivity of ovarian (OVCAR8) and uterine (ARK1) cancer cell lines to SQ1274 and paclitaxel using XTT assays. We used western blot and quantitative real-time PCR to analyze changes in AXL RNA and protein expression by SQ1274 and paclitaxel. Differences in cell-cycle arrest and apoptosis were investigated using flow cytometry. Finally, we treated ovarian and uterine xenograft models with vehicle, paclitaxel, or SQ1274.

RESULTS

First, we demonstrate that SQ1274 has a much lower IC₅₀ than paclitaxel in both ARK1 (1.26 nM vs. 15.34 nM, respectively) and OVCAR8 (1.34 nM vs. 10.29 nM, respectively) cancer cell lines. Second, we show SQ1274 decreases both RNA and protein expression of AXL. Third, we show that SQ1274 causes increased cell-cycle arrest and apoptosis compared to paclitaxel. Finally, we report that SQ1274 more effectively inhibits tumor growth in vivo compared to paclitaxel.

CONCLUSIONS

SQ1274 presents as a viable alternative to paclitaxel for treating ovarian and uterine cancer. This study supports the development of SQ1274 as a chemotherapeutic to treat ovarian and uterine cancer.

Gynecologic Oncologists' Perceptions of Palliative Care and Associated Barriers: A Survey of the Society of Gynecologic Oncology

OBJECTIVES

Gynecologic oncologists frequently care for patients at the end of life with the aid of palliative care (PC) specialists. Our primary objectives were to identify perceived barriers to integrating specialty PC into gynecologic cancer care.

MATERIALS AND METHODS

Members of the Society of Gynecologic Oncology (SGO) were invited to participate in an anonymous online survey. A Likert scale captured perceptions regarding primary and specialty PC, frequent barriers to use of PC, and potential interventions.

RESULTS

A total of 174 (16%) gynecologic oncologists completed the survey. The majority (75%) agreed or strongly agreed that PC should be integrated into cancer care at diagnosis of advanced or metastatic cancer. The most frequently perceived PC barriers included patients' unrealistic expectations (54%), limited access to specialty PC (25%), poor reimbursement (25%), time constraints (22%), and concern of reducing hope or trust (21%). The most agreed upon potential intervention was increased access to outpatient PC (80%).

CONCLUSIONS

According to this cohort of SGO members, families' or patients' unrealistic expectations are the most frequent barriers to specialty PC. Understanding this communication breakdown is critically important.

AXL modulates extracellular matrix protein expression and is essential for invasion and metastasis in endometrial cancer

The receptor tyrosine kinase AXL promotes migration, invasion, and metastasis. Here, we evaluated the role of AXL in endometrial cancer. High immunohistochemical expression of AXL was found in 76% (63/83) of advanced-stage, and 77% (82/107) of high-grade specimens and correlated with worse survival in uterine serous cancer patients. In vitro, genetic silencing of AXL inhibited migration and invasion but had no effect on proliferation of ARK1 endometrial cancer cells. AXL-deficient cells showed significantly decreased expression of phospho-AKT as well as uPA, MMP-1, MMP-2, MMP-3, and MMP-9. In a xenograft model of human uterine serous carcinoma with AXL-deficient ARK1 cells, there was significantly less tumor burden than xenografts with control ARK1 cells. Together, these findings underscore the therapeutic potentials of AXL as a candidate target for treatment of metastatic endometrial cancer.

Inhibition of the Receptor Tyrosine Kinase AXL Restores Paclitaxel Chemosensitivity in Uterine Serous Cancer

Uterine serous cancer (USC) is aggressive, and the majority of recurrent cases are chemoresistant. Because the receptor tyrosine kinase AXL promotes invasion and metastasis of USC and is implicated in chemoresistance in other cancers, we assessed the role of AXL in paclitaxel resistance in USC, determined the mechanism of action, and sought to restore chemosensitivity by inhibiting AXL in vitro and in vivo We used short hairpin RNAs and BGB324 to knock down and inhibit AXL. We assessed sensitivity of USC cell lines to paclitaxel and measured paclitaxel intracellular accumulation in vitro in the presence or absence of AXL. We also examined the role of the epithelial-mesenchymal transition (EMT) in AXL-mediated paclitaxel resistance. Finally, we treated USC xenografts with paclitaxel, BGB324, or paclitaxel plus BGB324 and monitored tumor burden. AXL expression was higher in chemoresistant USC patient tumors and cell lines than in chemosensitive tumors and cell lines. Knockdown or inhibition of AXL increased sensitivity of USC cell lines to paclitaxel in vitro and increased cellular accumulation of paclitaxel. AXL promoted chemoresistance even in cells that underwent the EMT in vitro Finally, in vivo studies of combination treatment with BGB324 and paclitaxel showed a greater than 51% decrease in tumor volume after 2 weeks of treatment when compared with no treatment or single-agent treatments (P < 0.001). Our results show that AXL expression mediates chemoresistance independent of EMT and prevents accumulation of paclitaxel. This study supports the continued investigation of AXL as a clinical target, particularly in chemoresistant USC. Mol Cancer Ther; 16(12); 2881-91. ©2017 AACR.

Comparison of bevacizumab alone or with chemotherapy in recurrent ovarian cancer patients

BACKGROUND

To compare the efficacy of chemotherapy (C) combined with bevacizumab (Bev) versus Bev alone in recurrent, heavily pretreated epithelial ovarian cancer (EOC).

METHODS

A multicenter analysis of patients treated from 2004 to 2011 was performed. Demographic, treatment, response, and adverse event information were obtained. Progression-free (PFS) and overall survival (OS) were analyzed.

RESULTS

Of 277 patients (median age: 58years), the majority had Stage III and IV (86%) disease, and 72% had serous histology. 244 (88%) were treated with C+Bev and 33 (12%) with Bev. Corresponding median progression-free survival (PFS) was 8.7 and 6.7months, and median overall survival (OS) was 14.3 and 10.5months, respectively. The chemotherapeutic agents combined with Bev and the median OS include: pegylated liposomal doxorubicin (n=19, OS of 20.4months), taxanes (n=55, OS of 20.2months), gemcitabine (n=106, OS of 14.1months), topotecan (n=43, OS of 13months), and cyclophosphamide (n=21, OS of 13months). There was no significant difference in toxicities between the C+Bev vs. Bev alone group.

CONCLUSION

This retrospective analysis supports that combination chemotherapy and bevacizumab prolongs PFS and OS compared with bevacizumab alone.