Whitfield B. Growdon

Uterine carcinoma (UC) is the most common gynecologic malignancy in the United States. TP53 mutant UCs cause a disproportionate number of deaths due to limited therapies for these tumors and the lack of mechanistic understanding of their fundamental vulnerabilities. Here we sought to understand the functional and therapeutic relevance of TP53 mutations in UC. We functionally profiled targetable TP53 dependent DNA damage repair and cell cycle control pathways in a panel of TP53 mutant UC cell lines and patient-derived organoids. There were no consistent defects in DNA damage repair pathways. Rather, most models demonstrated dependence on defective G2/M cell cycle checkpoints and subsequent upregulation of Aurora kinase-LKB1-p53-AKT signaling in the setting of baseline mitotic defects. This combination makes them sensitive to Aurora kinase inhibition. Resistant lines demonstrated an intact G2/M checkpoint, and combining Aurora kinase and WEE1 inhibitors, which then push these cells through mitosis with Aurora kinase inhibitor-induced spindle defects, led to apoptosis in these cases. Overall, this work presents Aurora kinase inhibitors alone or in combination with WEE1 inhibitors as relevant mechanism driven therapies for TP53 mutant UCs. Context specific functional assessment of the G2/M checkpoint may serve as a biomarker in identifying Aurora kinase inhibitor sensitive tumors.

Introduction Fifteen per cent of women with cervical cancer are diagnosed with advanced disease and carry a 5 year survival rate of only 17%. Cervical cancer may lead to particularly severe symptoms that interfere with quality of life, yet few studies have examined the rate of palliative care referral in this population. This study aims to examine the impact of palliative care referral on women who have died from cervical cancer in two tertiary care centers. Methods We conducted a retrospective review of cervical cancer decedents at two tertiary institutions from January 2000 to February 2017. We examined how aggressive measures of care at the end of life, metrics defined by the National Quality Forum, interacted with clinical variables to understand if end-of-life care was affected. Univariate and multivariate parametric and non-parametric testing was used, and linear regression models were generated to determine unadjusted and adjusted associations between aggressive measures of care at the end of life with receipt of palliative care as the main exposure. Results Of 153 cervical cancer decedents, 73 (47%) received a palliative care referral and the majority (57%) of referrals occurred during an inpatient admission. The median time from palliative care consultation to death was 2.3 months and 34% were referred to palliative care in the last 30 days of life. Palliative care referral was associated with fewer emergency department visits (OR 0.18, 95% CI 0.05 to 0.56), inpatient stays (OR 0.21, 95% CI 0.07 to 0.61), and intensive care unit admissions (OR 0.24, 95% CI 0.06 to 0.93) in the last 30 days of life. Palliative care did not affect chemotherapy or radiation administration within 14 days of death (p=0.36). Women evaluated by palliative care providers were less likely to die in the acute care setting (OR 0.19, 95% CI 0.07 to 0.51). Discussion In two tertiary care centers, less than half of cervical cancer decedents received palliative care consultations, and those referred to palliative care were often evaluated late in their disease course. Palliative care utilization was also associated with a lower incidence of poor-quality end-of-life care.

One of the most significant therapeutic challenges in the treatment of ovarian cancer is the development of recurrent platinum-resistant disease. Cancer stem cells (CSCs) are postulated to contribute to recurrent and platinum-resistant ovarian cancer (OvCa). Drugs that selectively target CSCs may augment the standard of care cytotoxics and have the potential to prevent and/or delay recurrence. Increased reliance on metabolic pathway modulation in CSCs relative to non-CSCs offers a possible therapeutic opportunity. We demonstrate that treatment with the metabolic inhibitor CPI-613 (devimistat, an inhibitor of tricarboxylic acid (TCA) cycle) in vitro decreases CD133+ and CD117+ cell frequency relative to untreated OvCa cells, with negligible impact on non-CSC cell viability. Additionally, sphere-forming capacity and tumorigenicity in vivo are reduced in the CPI-613 treated cells. Collectively, these results suggest that treatment with CPI-613 negatively impacts the ovarian CSC population. Furthermore, CPI-613 impeded the unintended enrichment of CSC following olaparib or carboplatin/paclitaxel treatment. Collectively, our results suggest that CPI-613 preferentially targets ovarian CSCs and could be a candidate to augment current treatment strategies to extend either progression-free or overall survival of OvCa.

Pre-clinical studies have demonstrated that natural and synthetic histone deacetylase (HDAC) inhibitors can impede the in vitro and in vivo growth of cell lines from a variety of gynecologic and other malignancies. We investigated the anti-tumor activity of panobinostat (LBH589) both in vitro and in vivo as either a single agent or in combination with conventional cytotoxic chemotherapy using patient-derived xenograft (PDX) models of primary serous ovarian tumors. The ovarian cancer cell lines OVCAR8, SKOV3 and their paclitaxel-resistant derivatives OVCAR8-TR and SKOV3-TR were treated with increasing doses of LBH589. The effect of LBH589 on cell viability was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Serially transplanted primary human high-grade serous ovarian adenocarcinoma tissue was utilized to generate xenografts in 6-week old female NOD/SCID mice. The mice were then randomized into one of 4 treatment groups: (1) vehicle control; (2) paclitaxel and carboplatin (P/C); (3) LBH589; or (4) P/C + LBH589. Mice were treated for 21 days and tumor volumes and mouse weights were obtained every 3 days. These experiments were performed in triplicate with three different patient derived tumors. Wilcoxan rank-sum testing was utilized to assess tumor volume differences. In vitro treatment with LBH589 significantly reduced the viability of both taxol-sensitive and taxol-resistant ovarian cancer cell lines (p < 0.01). In vivo treatment with LBH589 alone appeared tumorstatic and reduced tumor growth when compared to vehicle treatment (p < 0.007) after 21 days. This single agent activity was confirmed in two additional experiments with other PDX tumors (p < 0.03, p < 0.05). A potential additive effect of LBH589 and P/C, manifested as enhanced tumor regression with the addition of LBH589 compared to vehicle (p < 0.02), in one of the three analyzed serous PDX models. Our findings suggest that pan-HDAC inhibition with panobinostat precludes the growth of ovarian cancer cell lines in vitro and PDXs in vivo. Added benefit of LBH589 to standard P/C therapy was observed in one of three PDX models suggesting improved response in a subset of serous ovarian cancers.