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Chemotherapy-induced cognitive impairment (CICI) is often reported as a neurotoxic side effect of chemotherapy. Although CICI has emerged as a significant medical problem, meaningful treatments are not currently available due to a lack of mechanistic understanding underlying CICI pathophysiology. Using the platinum-based chemotherapy cisplatin as a model for CICI, we show here that cisplatin suppresses nicotinamide adenine dinucleotide (NAD+) levels in the adult female mouse brain in vivo and in human cortical neurons derived from induced pluripotent stem cells in vitro. Increasing NAD+ levels through nicotinamide mononucleotide (NMN) administration prevented cisplatin-induced abnormalities in neural progenitor proliferation, neuronal morphogenesis, and cognitive function without affecting tumor growth and antitumor efficacy of cisplatin. Mechanistically, cisplatin inhibited expression of the NAD+ biosynthesis rate-limiting enzyme nicotinamide phosphoribosyl transferase (Nampt). Selective restoration of Nampt expression in adult-born neurons was sufficient to prevent cisplatin-induced defects in dendrite morphogenesis and memory function. Taken together, our findings suggest that aberrant Nampt-mediated NAD+ metabolic pathways may be a key contributor in cisplatin-induced neurogenic impairments, thus causally leading to memory dysfunction. Therefore, increasing NAD+ levels could represent a promising and safe therapeutic strategy for cisplatin-related neurotoxicity. Significance: Increasing NAD+ through NMN supplementation offers a potential therapeutic strategy to safely prevent cisplatin-induced cognitive impairments, thus providing hope for improved quality of life in cancer survivors.

In ovarian cancer (OC), IL-17-producing T cells (Th17s) predict improved survival, whereas regulatory T cells predict poorer survival. We previously developed a vaccine whereby patient-derived dendritic cells (DCs) are programmed to induce Th17 responses to the OC antigen folate receptor alpha (FRα). Here we report the results of a single-arm open-label phase I clinical trial designed to determine vaccine safety and tolerability (primary outcomes) and recurrence-free survival (secondary outcome). Immunogenicity is also evaluated. Recruitment is complete with a total of 19 Stage IIIC-IV OC patients in first remission after conventional therapy. DCs are generated using our Th17-inducing protocol and are pulsed with HLA class II epitopes from FRα. Mature antigen-loaded DCs are injected intradermally. All patients have completed study-related interventions. No grade 3 or higher adverse events are seen. Vaccination results in the development of Th1, Th17, and antibody responses to FRα in the majority of patients. Th1 and antibody responses are associated with prolonged recurrence-free survival. Antibody-dependent cell-mediated cytotoxic activity against FRα is also associated with prolonged RFS. Of 18 patients evaluable for efficacy, 39% (7/18) remain recurrence-free at the time of data censoring, with a median follow-up of 49.2 months. Thus, vaccination with Th17-inducing FRα-loaded DCs is safe, induces antigen-specific immunity, and is associated with prolonged remission., The folate receptor alpha (FRα) is overexpressed in the majority of high-grade serous ovarian cancers and has been proposed as a candidate vaccine antigen. Here the authors report the safety and immunogenicity of Th17-inducing dendritic cells pulsed with FRα-derived epitopes in an early phase I clinical trial with ovarian cancer patients.

ObjectiveThe role of the different types of adjuvant treatments in endometrial cancer with para-aortic node metastases is unclear. The aim of this study was to report oncologic outcomes after adjuvant therapy in patients with stage IIIC2 endometrial cancer.MethodsThis retrospective single-institution study assessed patients with stage IIIC2 endometrial cancer who underwent primary surgery from January 1984 to December 2014. All patients had hysterectomy (±salpingo-oophorectomy) plus lymphadenectomy (para-aortic nodes, ±pelvic nodes). We included all patients with stage III endometrial cancer and documented para-aortic lymph node metastases (International Federation of Obstetrics and Gynecologists stage IIIC2). We excluded patients who did not provide consent, who had synchronous cancer, or who underwent neoadjuvant chemotherapy. Follow-up was restricted to the first 5 years post-operatively. Cox proportional hazards models, with age as the time scale, was used to evaluate associations of risk factors with disease-free survival and overall survival.ResultsAmong 105 patients with documented adjuvant therapy, external beam radiotherapy was administered to 25 patients (24%), chemotherapy to 24 (23%), and a combination (chemotherapy and external beam radiotherapy) to 56 (53%) patients. Most patients receiving chemotherapy and external beam radiotherapy (80%) had chemotherapy first. The majority of relapses had a distant component (31/46, 67%) and only one patient had an isolated para-aortic recurrence. Non-endometrioid subtypes had poorer disease-free survival (HR 2.57; 95% CI 1.38 to 4.78) and poorer overall survival (HR 2.00; 95% CI 1.09 to 3.65) compared with endometrioid. Among patients with endometrioid histology (n=60), chemotherapy and external beam radiotherapy improved disease-free survival (HR 0.22; 95% CI 0.07 to 0.71) and overall survival (HR 0.28; 95% CI 0.09 to 0.89) compared with chemotherapy or external beam radiotherapy alone. Combination therapy did not improve prognosis for patients with non-endometrioid histology (n=45).ConclusionsIn our cohort of patients with stage IIIC2 endometrioid endometrial cancer, those receiving chemotherapy and external beam radiotherapy had improved survival compared with patients receiving chemotherapy or external beam radiotherapy alone. However, the prognosis of patients with non-endometrioid endometrial cancer remained poor, regardless of the adjuvant therapy administered. Distant recurrences were the most common sites of failure.

BackgroundATRC-101 is an engineered version of an immunoglobulin G1 antibody that was discovered in a patient with non-small cell lung cancer (NSCLC) experiencing stable disease while being treated with anti–programmed death-1 therapy. ATRC-101 targets a tumor-specific ribonucleoprotein complex containing polyadenylate binding protein-1, which has been found to be present in the majority of NSCLC, acral melanoma, breast, colorectal, and ovarian cancer samples tested. Target immunoreactivity and single-agent activity have been observed in mouse models. Preclinical data suggest that ATRC-101 stimulates both innate and adaptive immune activity against tumors.MethodsATRC-101-A01 is a phase 1b trial (3+3 dose escalation with expansion cohorts) in patients with solid tumors treated with ATRC-101 monotherapy every 2 or 3 weeks (Q2W or Q3W), or ATRC-101 in combination with pembrolizumab, until unacceptable toxicity or disease progression at doses of 0.3–30 mg/kg, pending dose-limiting toxicities. The primary objective is safety and secondary objectives are to characterize the pharmacokinetic profile, immunogenicity, and anti-tumor activity of ATRC-101, and to determine the recommended dose for expansion. Pharmacodynamic studies will also be performed to evaluate changes from baseline in specific immune cell populations and cytokine levels in blood and tumors. Results from the ATRC-101 0.3–30 mg/kg monotherapy Q3W cohorts are presented in this abstract (data cutoff: July 16, 2021).ResultsTwenty-four participants with solid tumors (13 colorectal, 5 ovarian, 3 breast, 2 NSCLC, 1 acral melanoma) aged 27–75 years with a median 5 lines of prior therapy were treated Q3W in five dose cohorts. No dose-limiting toxicities were observed. Eight participants (33%) experienced grade ≥3 treatment-emergent adverse events. The maximum serum concentration of ATRC-101 and treatment exposure appeared to be dose proportional. Stable disease was observed in eight patients and best response per RECIST v1.1 was associated with expression of the ATRC-101 target. Multiple biomarkers, such as treatment-associated changes in the composition of CD3+, CD4+, and CD8+ T cells in the blood, and serum cytokines/chemokines, including those predicted to activate antigen-presentation pathways, support the proposed mechanism of action of ATRC-101 and will be presented.ConclusionsThese first-in-human data suggest a manageable safety profile for ATRC-101 Q3W, with no dose-limiting toxicities observed. Pharmacokinetics appear to be dose proportional. Enrollment in the Q2W monotherapy dose-escalation cohort and at the 30 mg/kg dose level Q3W is continuing. Trial sites have been activated to test ATRC-101 in combination with pembrolizumab, and combination with chemotherapy is also planned.Trial RegistrationTrial Registration: NCT04244552Ethics ApprovalThis study was approved by the institutional review board or ethics committee as required for each participating site.

Although 70–80% of newly diagnosed ovarian cancer patients respond to first-line therapy, almost all relapse and five-year survival remains below 50%. One strategy to increase five-year survival is prolonging time to relapse by improving first-line therapy response. However, no biomarker today can accurately predict individual response to therapy. In this study, we present analytical and prospective clinical validation of a new test that utilizes primary patient tissue in 3D cell culture to make patient-specific response predictions prior to initiation of treatment in the clinic. Test results were generated within seven days of tissue receipt from newly diagnosed ovarian cancer patients obtained at standard surgical debulking or laparoscopic biopsy. Patients were followed for clinical response to chemotherapy. In a study population of 44, the 32 test-predicted Responders had a clinical response rate of 100% across both adjuvant and neoadjuvant treated populations with an overall prediction accuracy of 89% (39 of 44, p

Dissemination of ovarian cancer cells can lead to inoperable metastatic lesions in the bowel and omentum that cause patient death. Here we show that LRRC15, a type-I 15-leucine–rich repeat-containing membrane protein, highly overexpressed in ovarian cancer bowel metastases compared with matched primary tumors and acts as a potent promoter of omental metastasis. Complementary models of ovarian cancer demonstrated that LRRC15 expression leads to inhibition of anoikis-induced cell death and promotes adhesion and invasion through matrices that mimic omentum. Mechanistically, LRRC15 interacted with β1-integrin to stimulate activation of focal adhesion kinase (FAK) signaling. As a therapeutic proof of concept, targeting LRRC15 with the specific antibody–drug conjugate ABBV-085 in both early and late metastatic ovarian cancer cell line xenograft models prevented metastatic dissemination, and these results were corroborated in metastatic patient-derived ovarian cancer xenograft models. Furthermore, treatment of 3D-spheroid cultures of LRRC15-positive patient-derived ascites with ABBV-085 reduced cell viability. Overall, these data uncover a role for LRRC15 in promoting ovarian cancer metastasis and suggest a novel and promising therapy to target ovarian cancer metastases. Significance: This study identifies that LRRC15 activates β1-integrin/FAK signaling to promote ovarian cancer metastasis and shows that the LRRC15-targeted antibody–drug conjugate ABBV-085 suppresses ovarian cancer metastasis in preclinical models.

Objectives: Women with stage IB endometrioid endometrial cancer (EEC) are at risk of developing non-vaginal recurrences. However, it is unclear which patients have high enough risk to justify testing systemic therapies. Our aim is to identify significant risk factors for non-vaginal recurrence. Methods: This is a retrospective multicenter study, including patients who underwent complete surgical staging for EEC at Mayo Clinic, Rochester (MN, USA) between January 1999-December 2017, and at Fondazione Policlinico Gemelli (Rome, Italy) between March 2002-March 2017, with a final FIGO stage IB. Patients without lymph node assessment were excluded. Recurrences were categorized into isolated vaginal and non-vaginal (hematogenous, peritoneal, lymphatic, or multi-site). The follow-up was restricted to the first 5 years following surgery. Recurrence-free survival (RFS) was estimated using the Kaplan-Meier method. Cox proportional hazards models, stratified by center, were fit to evaluate the association of clinical and pathologic characteristics with the risk of recurrence. Results: Three hundred eighty-six patients were identified. The mean myometrial invasion (MI) of the cohort was 70.4% (SD 13.2). The majority of the patients received either vaginal brachytherapy (VB) or no adjuvant therapy (N=256, 66.3%), 57 patients (14.8%) received EBRT ± chemotherapy ± VB, 38 (9.8%) received chemotherapy ± VB, and 35 (9.1%) unknown. Greater MI was associated with increased histologic grade and lymph vascular space invasion (LVSI). We identified 51 recurrences (14 isolated vaginal, and 37 non-vaginal); the median follow-up of the remaining patients was 4.5 (IQR, 2.3-6.9) years. The 5-year RFS for non-vaginal recurrences was 88.1% (95% CI 84.4-91.9%). There was a strong linear relationship between the percent of MI and the risk of recurrence. Patients with the deepest MI (≥90%) had a rate of recurrence as high as 40%. At univariate analysis, the risk of non-vaginal recurrence increased as the percent of MI increases (vs. MI 50-69.9%), with a hazard ratio (HR) of 3.33 (95% CI, 1.46-7.58) in patients with MI 70 to 89%, and HR of 8.47 (95% CI, 3.26-22.01) with MI≥ 90%. Patients with grade 3 disease had a higher risk of non-vaginal recurrence compared to grade 1-2 (HR 3.58, 95% CI, 1.86-6.88). At multivariate analysis, both histologic grade and depth of MI were independent predictors of recurrence. In particular, the subset of patients with MI≥ 70% and grade 3 tumors have the poorest RFS; however, we noticed also that patients with myometrial invasion ≥ 90% have a very high risk of recurrence independently from histologic grade (Table). Download : Download high-res image (68KB) Download : Download full-size image Conclusions: Considering women with stage IB endometrioid endometrial cancer, the rate of non-vaginal recurrences at 5 years is very high (> 30%): (1) in patients with any grade with MI≥ 90%; and (2) in grade 3 patients with MI≥ 70%. In the future, these pathologic findings could help us identify subgroups of patients in which systemic therapies may be tested.

Objectives: Historically, patients with early-stage high-intermediate risk (HIR) endometrioid endometrial cancer (EC) have been known to benefit from improved recurrence-free survival (RFS) with the use of adjuvant therapy. However, specific subgroups of HIR patients may benefit from observation ± vaginal brachytherapy (VB) only. We sought to evaluate RFS and cause-specific survival (CSS) after observation ± VB in the subgroups of early-stage HIR endometrioid EC. Methods: We identified patients with early-stage HIR endometrioid EC, who underwent a total hysterectomy, bilateral salpingo-oopho-rectomy, and sentinel lymph node biopsy or pelvic ± paraaortic lymphadenectomy at Mayo Clinic and Cleveland Clinic between 1999 and 2016. HIR group was defined based on revised GOG99 criteria used in the GOG249 trial: age ≥70 with 1 risk factor, age ≥50 with 2 risk factors, or all the 3 risk factors (grade 2-3, ≥50% myometrial invasion, or positive lymphovascular space invasion [LVSI]). HIR subgroups were determined by all possible combinations of risk factors, and 3-year RFS, site-specific RFS, and CSS were estimated. Results: Among 1,507 women with stage I or II EC, 447 stage I endometrioid EC patients were identified who fulfilled HIR criteria, and 349 (78.1%) were managed with observation ± VB. Eleven subgroups were defined and evaluated (Table). Among stage IA patients (1-5 subgroups), subgroup 5 (G3 ≥50y LVSI+) had the lowest RFS and CSS of 68.9% (46.6-100.0%) and 86.7% (71.1-100.0%), respectively, whereas the remaining 4 subgroups had 3-year RFS and CSS >90%. In all stage IA subgroups, 3-year lymphatic RFS was >90%; 3-year distant RFS was lowest in subgroup 5 (79.6% [56.9-100.0%] and 97.1% [91.8-100.0%] in subgroup 3 [G2 ≥50y LVSI+]). Additionally, 3-year CSS was 90%. Conversely, all stage IB subgroups experienced distant recurrence; 3-year distant RFS ranged from 73.1% (53.5-99.7%) to 96.5% (91.8-100.0%). 3-year distant RFS lower than 90% was observed in those subgroups with grade 3 or positive LVSI (7, 9, 10, and 11). Conclusions: Our results suggest that observation ± VB can be sufficient in some subgroups of stage I endometrioid HIR patients, specifically stage IA endometrioid HIR EC without the concomitant presence of grade 3 and LVSI. Among stage IB endometrioid HIR EC subgroups, particularly those with grade 3 or LVSI, observation ± VB is associated with lower RFS and CSS. Stratifying HIR patients into risk subgroups would alleviate the risk of overtreatment and undertreatment among patients with early-stage endometrioid EC; in this regard, the molecular characterization will provide a further instrument to achieve this objective.

Objectives: Up-regulation of ERBB pathways represent targetable alterations in many high grade endometrial cancers (EC); ERBB3 amplifications in particular may contribute to ineffective pathway targeting due to persistent co-activation of other ERBB binding partners, leading to tumor growth and survival. The efficacy of downstream dual-inhibition of MEK+AKT or MEK+PI3K in an ERBB3 amplified EC primary tumor was studied using a microcancer 3D ex-vivo tumor cell viability assay. Methods: Tumor was prospectively collected from a patient with stage II, FIGO grade 3, serous EC and genomic characterization was performed using multiple sequencing methods: whole exome, RNA, and MatePair analysis. Somatic mutations, structural variance, with transcriptomic profiling was used to identify potential driver pathways for subsequent pharmacologic inhibition. Primary tumor cells were grown in a three-dimensional environment and the formed microcancers were subjected to drug treatment. Cell viability was determined by the CellTiter-Glow Luminescent Assay. Data transformation and dose-response curves were generated using GraphPad PRISM using four parameter logistic regression. CompuSyn software with the Chou-Talalay method was used to analyze drug interactions and synergy. The Fractional response-Combination index (Fa-CI) plot was generated with Microsoft Excel. Capivasertib, GDC-0084, and cobimetinib were used to inhibit AKT, PI3K/mTOR, and MEK, respectively. Inhibitory effect was defined as percent reduction in ATP at clinically-defined predicted plasma maximum concentration (Cmax) values. Results: Genomic sequencing revealed overexpression of a mutated ERBB3 (c.889G>T; p.Asp297Tyr) transcript within a 6N focal amplification. Additional pertinent alterations included a MYC mid-level gain, and TP53 double hit (loss and exonic splicing silencer (ESS)). Inhibition of cell viability was moderate by single agents: capivasertib, cobimetanib, or GDC-0084, as shown by inhibitory effect values of 33.9%, 35.9% and 49.9%, respectively. Two combinations with cobimetinib demonstrated increasing inhibitory effect values of 76.2% for cobimetanib/capivasertib at the Cmax of capivasertib and 79.7% for cobimetanib/GDC-0084 at the Cmax of cobimetanib. Synergy was evidenced by a combination index 0.8 (Figure 1). Download : Download high-res image (185KB) Download : Download full-size image Conclusions: Combined inhibition of MEK and PI3K-AKT-mTOR pathways synergistically suppress viability in a patient-derived high-grade serous EC harboring a ERBB3 amplification. Further ex-vivo testing should be performed in endometrial tumors with other ERBB3 aberrations to allow generalization of results.

Ovarian carcinosarcoma (OCS) is an aggressive and rare tumour type with limited treatment options. OCS is hypothesised to develop via the combination theory from a single progenitor, resulting in carcinomatous and sarcomatous components, or alternatively via the conversion theory, with the sarcomatous component developing from the carcinomatous component through epithelial-to-mesenchymal transition (EMT). We show OCS from 18 women to be monoclonal through analysis of DNA variants from isolated carcinoma and sarcoma components. RNA sequencing indicated the carcinoma components were more mesenchymal when compared with pure ovarian carcinomas, supporting the conversion theory. We used pre-clinical OCS models to test the efficacy of microtubule-targeting drugs, including eribulin, which has been shown to reverse EMT characteristics. We demonstrated that microtubule inhibitors, vinorelbine and eribulin, were more effective than standard-of-care platinum-based chemotherapy. Eribulin reduced mesenchymal characteristics, N-MYC expression and cholesterol biosynthesis. Finally, eribulin induced a strong immune response, supporting immunotherapy combinations in the clinic.

Objective We describe a phase II clinical trial of the combination of ribociclib and letrozole for treatment of relapsed oestrogen receptor (ER)-positive ovarian cancer (OC) and endometrial cancer (EC). The primary endpoint was the proportion of patients alive, progression-free survival (PFS), and still on treatment at 12 weeks (PFS12), with 45% or greater considered positive. Methods Patients with measurable, relapsed ER-positive OC or EC (platinum-sensitive or resistant) were eligible and treated with 400 mg of oral ribociclib and 2.5 mg of oral letrozole daily. Patient-derived xenografts (PDXs) were created from imaging-guided tumour biopsies. Results Forty patients (20 OC and 20 EC) were enrolled. A PFS12 of 55% was observed in the EC cohort and 50% in the OC cohort. A PFS greater or equal to 24 weeks (PFS24) was seen in 20% (4/20) of the OC cohort and 35% (7/20) of the EC cohort. The greatest benefit was seen in low-grade serous OC (LGSOC) (3/3, 100% PFS24) and grades 1 and 2 EC (5/11, 45% PFS24). All three LGSOC patients obtained at least a partial response lasting for over 2 years, with two of the three patients still on treatment. PDX tumour engraftment was feasible in 45% of patients. Positive survival effects of the combination of ribociclib and letrozole were observed in two of three EC PDX models. Conclusion Ribociclib and letrozole have promising clinical activity in relapsed ER-positive OC and EC, particularly in LGSOC and relapsed ER-positive grade 1 and 2 EC. Generation of PDX models is feasible with positive survival effects observed in EC models. Trial registration number ClinicalTrials.gov registry ( NCT02657928 ).

High stage and recurrent ovarian clear cell carcinoma (OCC) are associated with poor prognosis and resistance to chemotherapy. A distinguishing histological feature of OCC is abundant cytoplasmic stores of glucose, in the form of glycogen, that can be mobilized for cellular metabolism. Here, we report the effect on preclinical models of OCC of disrupting glycogen utilization using the glucose analogue 2-deoxy-D-glucose (2DG). At concentrations significantly lower than previously reported for other cancers, 2DG markedly improves the efficacy in vitro of carboplatin chemotherapy against chemo-sensitive TOV21G and chemo-resistant OVTOKO OCC cell lines, and this is accompanied by the depletion of glycogen. Of note, 2DG doses&mdash, of more than 10-fold lower than previously reported for other cancers&mdash, significantly improve the efficacy of carboplatin against cell line and patient-derived xenograft models in mice that mimic the chemo-responsiveness of OCC. These findings are encouraging, in that 2DG doses, which are substantially lower than previously reported to cause adverse events in cancer patients, can safely and significantly improve the efficacy of carboplatin against OCC. Our results thus justify clinical trials to evaluate whether low dose 2DG improves the efficacy of carboplatin in OCC patients.

Platinum-based DNA cross-linking agents are widely used anti-cancer drugs. Tumor resistance to platinum compounds is a major determinant of patient survival, including in high grade serous ovarian cancer (HGSOC). Remarkably, despite >30 years of literature on platinum responses in human cancer, none of these findings is used clinically as a predictive biomarker to stratify patients for platinum resistance, nor exploited therapeutically to treat platinum-resistant disease. Thus, understanding mechanisms of platinum resistance is an urgent goal, both to identify predictive biomarkers of platinum response (to spare patients with platinum-resistant tumors futile platinum therapy) and to develop efficacious therapies for platinum-resistant disease. To better understand mechanisms underlying platinum resistance in HGSOC, we performed comprehensive, dynamic (+/-carboplatin), multiomic profiling of DNA, RNA, protein and post-translational modifications (phosphorylation, ubiquitination, acetylation) to identify the cellular networks that respond to platinum treatment and associate with platinum resistance in three HGSOC intra-patient cell line pairs (PEA1S/PEA2R, PEO1S/PEO4R, PEO14S/PEO23R). The cell line pairs were derived from ascites or pleural effusions (Langdon et al., 1988) from three patients both before (PEA1S, PEO1S, PEO14S) and after (PEA2R, PEO4R, PEO23R, respectively) their tumors became clinically platinum resistant (i.e., in vivo development of resistance). The molecular profiles revealed extensive responses to carboplatin and differential responses between platinum-sensitive and platinum-resistant cells. Higher oxidative phosphorylation and fatty acid oxidation (FAO) pathway expression were observed in the platinum-resistant cells, which was further validated in patient-derived xenograft (PDX) models. We show that pharmacologic inhibition or CRISPR knockout of CPT1A, which represents a rate limiting step of FAO, sensitize HGSOC cells to platinum. Thus, FAO, and CPT1A in particular, represent a candidate therapeutic target to overcome platinum resistance in HGSOC. Citation Format: Hong Wang, Dongqing Hugang, Shrabanti Chowdhury, Sara Savage, Richard Ivey, Jacob Kennedy, Jeffrey Whiteaker, Chenwei Lin, Xiaonan Hou, Catherine Huntoon, Uliana Voytovich, Zahra Shire, Qing Yu, Steven Gygi, Andrew Hoofnagle, Zachary Herbert, Anna Calinawan, Larry Karnitz, S. John Weroha, Scott Kaufmann, Bing Zhang, Pei Wang, Michael Birrer, Amanda Paulovich. Multiomic analysis identifies CPT1A and fatty acid oxidation as a potential therapeutic target in platinum-refractory 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 1426.

Patient-derived tumor xenograft (PDX) mouse models have emerged as an important oncology research platform to study tumor evolution, mechanisms of drug response and resistance, and tailoring chemotherapeutic approaches for individual patients. The lack of robust standards for reporting on PDX models has hampered the ability of researchers to find relevant PDX models and associated data. Here we present the PDX models minimal information standard (PDX-MI) for reporting on the generation, quality assurance, and use of PDX models. PDX-MI defines the minimal information for describing the clinical attributes of a patient's tumor, the processes of implantation and passaging of tumors in a host mouse strain, quality assurance methods, and the use of PDX models in cancer research. Adherence to PDX-MI standards will facilitate accurate search results for oncology models and their associated data across distributed repository databases and promote reproducibility in research studies using these models. Cancer Res; 77(21); e62–66. ©2017 AACR.

Interest in preclinical drug development for ovarian cancer has stimulated development of patient-derived xenograft (PDX) or tumorgraft models. However, the unintended formation of human lymphoma in severe combined immunodeficiency (SCID) mice from Epstein-Barr virus (EBV)-infected human lymphocytes can be problematic. In this study, we have characterized ovarian cancer PDXs which developed human lymphomas and explore methods to suppress lymphoproliferative growth. Fresh human ovarian tumors from 568 patients were transplanted intraperitoneally in SCID mice. A subset of PDX models demonstrated atypical patterns of dissemination with mediastinal masses, hepatosplenomegaly, and CD45-positive lymphoblastic atypia without ovarian tumor engraftment. Expression of human CD20 but not CD3 supported a B-cell lineage, and EBV genomes were detected in all lymphoproliferative tumors. Immunophenotyping confirmed monoclonal gene rearrangements consistent with B-cell lymphoma, and global gene expression patterns correlated well with other human lymphomas. The ability of rituximab, an anti-CD20 antibody, to suppress human lymphoproliferation from a patient's ovarian tumor in SCID mice and prevent growth of an established lymphoma led to a practice change with a goal to reduce the incidence of lymphomas. A single dose of rituximab during the primary tumor heterotransplantation process reduced the incidence of CD45-positive cells in subsequent PDX lines from 86.3% (n = 117 without rituximab) to 5.6% (n = 160 with rituximab), and the lymphoma rate declined from 11.1% to 1.88%. Taken together, investigators utilizing PDX models for research should routinely monitor for lymphoproliferative tumors and consider implementing methods to suppress their growth.

// Sarah E. Gill 1 , Qing Zhang 1 , Gary L. Keeney 2 , William A. Cliby 1 and S. John Weroha 3 1 Department of Gynecologic Oncology, Mayo Clinic, Rochester, Minnesota, USA 2 Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA 3 Department of Medical Oncology, Mayo Clinic, Rochester, Minnesota, USA Correspondence to: S. John Weroha, email: Weroha.Saravut@mayo.edu Keywords: 3C23K, mullerian inhibiting substance receptor, ovarian cancer, targeted therapy, patient-derived xenograft Received: December 14, 2016 Accepted: July 03, 2017 Published: July 27, 2017 ABSTRACT MISIIR is a potential target for ovarian cancer (OC) therapy due to its tissue-specific pattern of expression. 3C23K is a novel therapeutic monoclonal anti-MISIIR antibody designed to recruit effector cells and promote cell death through ADCC (antibody dependent cell-mediated cytotoxicity). Our objective was to determine the tolerability and efficacy of 3C23K in OC patient-derived xenografts (PDX) and to identify factors affecting efficacy. Quantitative RT-PCR, immunohistochemistry (IHC), and flow cytometry were used to categorize MISIIR expression in established PDX models derived from primary OC patients. We selected two high expressing models and two low expressing models for in vivo testing. One xenograft model using an MISIIR over-expressing SKOV3ip cell line (Z3) was a positive control. The primary endpoint was change in tumor size. The secondary endpoint was final tumor mass. We observed no statistically significant differences between control and treated animals. The lack of response could be secondary to a number of variables including the lack of known biomarkers of response, the low membrane expression of MISIIR, and a limited ability of 3C23K to induce ADCC in PDX models. Further study is needed to determine the magnitude of ovarian cancer response to 3C23K and also if there is a threshold surface expression to predict response.

// Madalene A. Earp 1 , Rama Raghavan 2 , Qian Li 2, 10 , Junqiang Dai 2 , Stacey J. Winham 1 , Julie M. Cunningham 3 , Yanina Natanzon 1 , Kimberly R. Kalli 4 , Xiaonan Hou 5 , S. John Weroha 5, 6 , Paul Haluska 5, 6 , Kate Lawrenson 7 , Simon A. Gayther 8, 9 , Chen Wang 1 , Ellen L. Goode 1, * and Brooke L. Fridley 2, 10, * 1 Department of Health Sciences Research, Mayo Clinic, Rochester, MN, USA 2 Department of Biostatistics, University of Kansas Medical Center, KS, USA 3 Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA 4 Division of Medical Oncology, Mayo Clinic, Rochester, MN, USA 5 Department of Oncology, Mayo Clinic, Rochester, MN, USA 6 Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA 7 Women’s Cancer Program at the Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA 8 Center for Cancer Prevention and Translational Genomics, Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA 9 Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA 10 Department of Biostatistics and Bioinformatics, Moffitt Cancer Center, Tampa, FL, USA * These authors contributed equally to this work Correspondence to: Brooke L. Fridley, email: Brooke.Fridley@moffitt.org Keywords: fusion gene, ovarian cancer, RNA-sequencing, histological subtypes, TCGA Received: August 08, 2016 Accepted: March 22, 2017 Published: April 01, 2017 ABSTRACT Gene fusions play a critical role in some cancers and can serve as important clinical targets. In epithelial ovarian cancer (EOC), the contribution of fusions, especially by histological type, is unclear. We therefore screened for recurrent fusions in a histologically diverse panel of 220 EOCs using RNA sequencing. The Pipeline for RNA-Sequencing Data Analysis (PRADA) was used to identify fusions and allow for comparison with The Cancer Genome Atlas (TCGA) tumors. Associations between fusions and clinical prognosis were evaluated using Cox proportional hazards regression models. Nine recurrent fusions, defined as occurring in two or more tumors, were observed. CRHR1-KANSL1 was the most frequently identified fusion, identified in 6 tumors (2.7% of all tumors). This fusion was not associated with survival; other recurrent fusions were too rare to warrant survival analyses. One recurrent in-frame fusion, UBAP1-TGM7 , was unique to clear cell (CC) EOC tumors (in 10%, or 2 of 20 CC tumors). We found some evidence that CC tumors harbor more fusions on average than any other EOC histological type, including high-grade serous (HGS) tumors. CC tumors harbored a mean of 7.4 fusions (standard deviation [sd] = 7.4, N = 20), compared to HGS EOC tumors mean of 2.0 fusions (sd = 3.3, N = 141). Few fusion genes were detected in endometrioid tumors (mean = 0.24, sd = 0.74, N = 55) or mucinous tumors (mean = 0.25, sd = 0.5, N = 4) tumors. To conclude, we identify one fusion at 10% frequency in the CC EOC subtype, but find little evidence for common (> 5% frequency) recurrent fusion genes in EOC overall, or in HGS subtype-specific EOC tumors.

Background Poly(adenosine diphosphate ribose) polymerase (PARP) inhibitors exhibit promising activity against ovarian cancers, but their efficacy can be limited by acquired drug resistance. This study explores the role of autophagy in regulating the sensitivity of ovarian cancer cells to PARP inhibitors. Methods Induction of autophagy was detected by punctate LC3 fluorescence staining, LC3I to LC3II conversion on Western blot analysis, and electron microscopy. Enhanced growth inhibition and apoptosis were observed when PARP inhibitors were used with hydroxychloroquine, chloroquine (CQ), or LYS05 to block the hydrolysis of proteins and lipids in autophagosomes or with small interfering RNA against ATG5 or ATG7 to prevent the formation of autophagosomes. The preclinical efficacy of the combination of CQ and olaparib was evaluated with a patient-derived xenograft (PDX) and the OVCAR8 human ovarian cancer cell line. Results Four PARP inhibitors (olaparib, niraparib, rucaparib, and talazoparib) induced autophagy in a panel of ovarian cancer cells. Inhibition of autophagy with CQ enhanced the sensitivity of ovarian cancer cells to PARP inhibitors. In vivo, olaparib and CQ produced additive growth inhibition in OVCAR8 xenografts and a PDX. Olaparib inhibited PARP activity, and this led to increased reactive oxygen species (ROS) and an accumulation of γ-H2AX. Inhibition of autophagy also increased ROS and γ-H2AX and enhanced the effect of olaparib on both entities. Treatment with olaparib increased phosphorylation of ATM and PTEN while decreasing the phosphorylation of AKT and mTOR and inducing autophagy. Conclusions PARP inhibitor-induced autophagy provides an adaptive mechanism of resistance to PARP inhibitors in cancer cells with wild-type BRCA, and a combination of PARP inhibitors with CQ or other autophagy inhibitors could improve outcomes for patients with ovarian cancer.

ObjectivesInhibition of pregnancy-associated plasma protein-A (PAPP-A), an upstream activator of the insulin-like growth factor (IGF) pathway, is known to augment sensitivity to platinum-based chemotherapy. This study further tests the efficacy of PAPP-A inhibition with a monoclonal antibody inhibitor (mAb-PA) in ovarian cancer (OC) platinum-resistant patient-derived xenograft (PDX) models.MethodsPAPP-A expression was quantitated in platinum-resistant PDX models by ELISA. A subset with High (n = 5) and Low (n = 2) expression were revived in female SCID/beige mice for studies with either saline, carboplatin/paclitaxel (CP) + mAb-PA, or CP + IgG2a. The primary endpoint was tumor area by ultrasound on day 28 relative to baseline. Conversion to platinum-sensitive was defined by average tumor regression below baseline. Statistical analyses included linear mixed effects modeling and Kaplan Meier curves. Response to therapy was correlated with changes in the ratio of phosphorylated/total AKT and ERK 1/2 using Wes analysis.ResultsThe addition of mAb-PA to CP induced tumor regression below baseline in one High PAPP-A PDX model; another three models exhibited notable growth inhibition relative to CP + IgG2a. None of the Low PAPP-A PDX models regressed below baseline. The PDX model with the greatest magnitude of tumor regression from baseline after combination therapy was maintained on single agent mAb-PA or IgG2a, but no benefit was observed. Decreased phosphorylation of ERK1/2 correlated with conversion to platinum-sensitive.ConclusionsThe addition of mAb-PA to CP overcame platinum-resistance in one of five High PAPP-A PDX models; three other models demonstrated improved platinum-response. This supports further clinical development of this novel therapeutic.

Objective Poly(ADP-ribose) polymerase (PARP) inhibitors have yielded encouraging responses in high-grade serous ovarian carcinomas (HGSOCs), but the optimal treatment setting remains unknown. We assessed the effect of niraparib on HGSOC patient-derived xenograft (PDX) models as well as the relationship between certain markers of homologous recombination (HR) status, including BRCA1 / 2 mutations and formation of RAD51 foci after DNA damage, and response of these PDXs to niraparib in vivo . Methods Massively parallel sequencing was performed on HGSOCs to identify mutations contributing to HR deficiency. HR pathway integrity was assessed using fluorescence microscopy-based RAD51 focus formation assays. Effects of niraparib (MK-4827) on treatment-naive PDX tumor growth as monotherapy, in combination with carboplatin/paclitaxel, and as maintenance therapy were assessed by transabdominal ultrasound. Niraparib responses were correlated with changes in levels of poly(ADP-ribose), PARP1, and repair proteins by western blotting. Results Five PDX models were evaluated in vivo . Tumor regressions were induced by single-agent niraparib in one of two PDX models with deleterious BRCA2 mutations and in a PDX with RAD51C promoter methylation. Diminished formation of RAD51 foci failed to predict response, but Artemis loss was associated with resistance. Niraparib generally failed to enhance responses to carboplatin/paclitaxel chemotherapy, but maintenance niraparib therapy delayed progression in a BRCA2 -deficient PDX. Conclusions Mutations in HR genes are neither necessary nor sufficient to predict response to niraparib. Assessment of repair status through multiple complementary assays is needed to guide PARP inhibitor therapy, design future clinical trials and identify ovarian cancer patients most likely to benefit from PARP inhibition.

Although high-grade serous ovarian cancers (HGSOC) are highly chemosensitive with an 85% initial response rate to platinum-based chemotherapy, 15% of patients are “exceptional nonresponders,” with platinum-refractory tumors that remain stable or progress during treatment. Unfortunately, we have no predictive biomarkers to identify refractory patients up front, and they receive futile chemotherapy through which most patients become too ill to be eligible for clinical trials. Hence, no progress has been made in treating these deadly tumors. The goal of this study is to identify mechanisms of platinum refractoriness to: i) predict refractory HGSOCs up front and ii) identify potential new drug targets in refractory disease to point to desperately needed new therapeutic approaches. Of note, 80-90% of patients who are initially platinum responsive will relapse and develop platinum-resistant disease, and it is possible that findings in platinum-refractory tumors might also provide insights into platinum-resistant tumors. Our NCI Clinical Proteomic Tumor Analysis Consortium (CPTAC)-funded approach combines genomic and proteomic (“proteogenomic”) analyses of both preclinical models (0, 8, and 24 hours post-platinum exposure) and treatment-naïve human tumors. For preclinical models, we studied a well-characterized collection of patient-derived xenograft (PDX) models (10 sensitive, 10 refractory), as well as intrapatient HGSOC cell line pairs derived from patients before and after the development of platinum resistance. For the PDX models, proteogenomic profiling included RNASeq, WES, global proteomics, and phosphoproteomics at all 3 time points (0, 8, 24 hours). For cell line models (3 sensitive, 3 resistant), proteogenomic profiling was performed at all 3 timepoints (0, 8, 24 hours), and experiments were performed in complete biologic triplicate. Analyses included RNASeq, WES, global proteomics, phosphoproteomics, ubiquitin proteome, acetylated proteome, and pTyr. A large collection of 275 human HGSOCs (an approximate equal balance of platinum sensitive and refractory tumors) is currently undergoing proteomic profiling, and genomic profiles (WGS, RNASeq) will be performed on a subset. In parallel, we have performed a comprehensive review of 31 years of published work on platinum responses of human cancers, identifying ~700 genes implicated in the response and scoring each gene with respect to strength of the published evidence. Using a Bayesian approach, we are integrating the curated candidates from the literature with our empirical proteogenomic datasets to identify a candidate signature for detecting platinum-refractory disease prior to chemotherapy. We are also performing gene-regulatory network analysis to identify potential drivers of chemo response. NextGen, targeted, multiplex, multiple reaction monitoring mass spectrometry-based assays are being developed to quantify proteins in the signature for validation studies, using independent patient cohorts. This abstract is also being presented as Poster A62. Citation Format: Jacob J. Kennedy, Shrabanti Chowdhury, Sara R. Savage, Xiaonan Hou, Catherine J. Huntoon, Richard G. Ivey, Qing Yu, Chenwei Lin, Dongqing Huang, Lei Zhao, Uliana J. Voytovich, Regine M. Schoenherr, Zahra Shire, Steven J. Skates, Jeffrey R. Whiteaker, Andrew N. Hoofnagle, Samuel C. Mok, Bing Zhang, Larry M. Karnitz, S. John Weroha, Steven P. Gygi, Scott H. Kaufmann, Pei Wang, Michael J. Birrer, Amanda G. Paulovich. Proteogenomic approach to identify mechanisms of platinum refractoriness in high-grade serous ovarian cancers [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 PR02.

Objective: A growing number of cancer antineoplastic agents can cause life-threatening acute infusion reactions. Because previous studies have not studied these reactions from the perspective of patients, this study was undertaken with that objective in mind. Methods: Patients who had an acute infusion reaction were interviewed based on the Leventhal model. Once saturation of content was achieved, interviews were transcribed and analyzed with qualitative methodology. Results: Twenty-one patients were enrolled. Most were women (n = 15); the median age was 58 years, and paclitaxel was the most common inciting agent. Three themes emerged. First, these reactions are frightening; patients made remarks such as “I was just thinking oh my God, I am dying.” Second, prior education about these reactions seemed to mitigate this fear, “Basically everything the nurses told me potentially could happen, like happened. So, I was prepared.” Third, when health-care providers were prompt and attentive during the reaction, patients described less fear with future chemotherapy, “So no, I’m really not fearful about going in tomorrow because I know they’ll be there and they’ll be watching me.” Conclusion: These reactions evoke fear which can be mitigated with education prior to and with prompt responsiveness during the acute infusion reaction.

Physical function declines in old age, portending disability, increased health expenditures, and mortality. Cellular senescence, leading to tissue dysfunction, may contribute to these consequences of aging, but whether senescence can directly drive age-related pathology and be therapeutically targeted is still unclear. Here we demonstrate that transplanting relatively small numbers of senescent cells into young mice is sufficient to cause persistent physical dysfunction, as well as to spread cellular senescence to host tissues. Transplanting even fewer senescent cells had the same effect in older recipients and was accompanied by reduced survival, indicating the potency of senescent cells in shortening health- and lifespan. The senolytic cocktail, dasatinib plus quercetin, which causes selective elimination of senescent cells, decreased the number of naturally occurring senescent cells and their secretion of frailty-related proinflammatory cytokines in explants of human adipose tissue. Moreover, intermittent oral administration of senolytics to both senescent cell–transplanted young mice and naturally aged mice alleviated physical dysfunction and increased post-treatment survival by 36% while reducing mortality hazard to 65%. Our study provides proof-of-concept evidence that senescent cells can cause physical dysfunction and decreased survival even in young mice, while senolytics can enhance remaining health- and lifespan in old mice.

Objectives We report the results of a phase 2 clinical trial of the combination of everolimus and letrozole in patients with relapsed estrogen receptor-positive high-grade ovarian cancer. The trial's primary endpoint was the proportion of patients alive and progression-free after 12weeks of therapy with the combination of everolimus and letrozole. A 12-week PFS of 45% or greater was considered a positive result. The feasibility of generating patient-derived xenograft (PDX) models from biopsy specimens was also evaluated. Methods Eligibility criteria included relapsed estrogen receptor-positive ovarian, fallopian tube or primary peritoneal carcinomas with measurable disease, not previously treated with everolimus or AIs. Both platinum-resistant and sensitive tumors were included. Xenografts were created from image-guided tumor biopsies at baseline. Patients received oral everolimus 10mg daily and letrozole 2.5mg daily. Results Twenty patients were enrolled, 19 were evaluable. Nine out of 19 were alive, progression-free, and still on treatment at the 12week evaluation time-point (12-week PFS of 47%) with a median PFS of 3.9months (95% CI: 2.8–11.0). The median overall survival was 13.0months. Twelve patients (63%) experienced at least one grade 3 or worse adverse events. PDX tumor engraftment was feasible in the majority of patients (9 out of 17, 52.9%). Conclusions The combination of everolimus and letrozole is associated with a promising 47% 12-week PFS rate in patients with ER-positive relapsed high-grade ovarian cancer with acceptable toxicity. PDX tumor models can be generated from biopsies of ovarian tumors.

PURPOSE: Ovarian cancer remains the most lethal gynecological malignancy in the United States even though there are a number of treatment options. For the newly diagnosed ovarian cancer patient, treatment is standard with the majority of patients receiving first-line platinum/taxol treatment following surgical debulking or as part of a neo-adjuvant treatment regimen. Standard response assessment to this chemotherapy combination depends on lengthy clinical follow-up of at least 6 months following the conclusion of the chemotherapy. This course is initially effective in 70-80% of patients, but 20-30% will relapse within the 6 months post-chemotherapy or not respond at all. Additionally, most of the initial responders will also relapse. Early prediction of the patients whose cancers do not respond could lead to earlier intervention with more effective therapy. RESULTS: To perform this prediction, we developed a test utilizing live tumor tissue and 3D cell culture to predict the response of ovarian cancer patients to standard platinum and taxol chemotherapy along with the standard agents used for relapse patients. To validate the assay, we performed a prospective trial involving 86 women with newly diagnosed ovarian cancer from whom live tumor tissue was recovered at surgical resection prior to chemotherapy. Of the 79 patients whose tissues yielded a successful assay result, 27 had sufficient clinical follow-up to determine the accuracy of the response predictions made by the assay. Assay response predictions were made within 7 days following surgery while clinical response was not determined until 6 months or more following the conclusion of first-line chemotherapy. Assay results predicted first-line chemotherapy response in 100% of clinical responders (19 of 19) and first-line chemotherapy non-response in 62.5% of clinical non-responders (5 of 8) as defined by CA-125 and radiographic surveillance. This response prediction was statistically significant by Fisher's Exact test, p < 0.001. The sensitivity of the assay was 86% while the specificity was 100%. When the assay results were examined in terms of progression free survival, 19 of 19 patients identified as responders by the assay remained progression free at least 6 months post-chemotherapy with 14 remaining progression free 10 or more months post-chemotherapy. In contrast, of the 8 assay non-responders, 3 were refractory with progression within 3 months of chemotherapy conclusion and 2 progressed less than 6 months post-chemotherapy with a mean progression free survival of 4.5 months. CONCLUSIONS: Our rapid, ex vivo, 3D cellular assay is capable of accurate patient specific response prediction of first-line combination therapy in newly diagnosed ovarian cancer patients and can serve as a prognostic indicator of progression free survival. This preliminary clinical validation shows the significant potential of this assay as a future tool in personalized cancer care for ovarian cancer patients. Citation Format: Stephen Shuford, Jeffrey Elder, Larry Puls, John Weroha, Xiaonan Hou, Valentina Zanfagnin, Alpa Nick, Michael P. Stany, Larry Maxwell, Thomas Conrads, Chris Corless, Anil K. Sood, Matthew Gevaert, Howland E. Crosswell, and Teresa M. DesRochers. PROSPECTIVE CLINICAL VALIDATION OF EX VIVO, PATIENT-SPECIFIC RESPONSE PREDICTION TO FIRST-LINE CHEMOTHERAPY [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-069.

e17039 Background: Treatment strategies are needed for platinum-resistant recurrent ovarian cancer. Glucocorticoid receptor (GR) is associated with poor prognosis in ovarian cancer. GR signaling inhibits chemotherapy-induced cell death via transcriptional regulation of anti-apoptotic proteins. Non-selective (mifepristone) and selective GR antagonists (Relacorilant, Corcept Therapeutics) are under clinical development (eg. NCT02046421, NCT03776812). We hypothesized that GR antagonism would improve chemotherapy sensitivity in ovarian cancer patient-derived xenograft (PDX) models. Methods: Five PDX models were selected based on GR expression above median RNA seq levels. Tissues were transplanted into 300 female SCID-Bg mice at the Mayo Clinic. Once tumor diameter reached 0.2 cm, mice were randomized into treatment arms (2-25 mice per arm) and treated intraperitoneal (i.p): control (9% saline, CTL) on day 0 (D0), 1, 7, 8, 14, 15, 21, 22; mifepristone (MIF), 15 mg/kg D0, 1, 7, 8, 14, 15, 21, 22; relacorilant (134), 20 mg/kg D0, 1, 7, 8, 14, 15, 21, 22; carboplatin (CBDCA) at the MTD, 51 mg/kg D1, 8, 15, 22; CBDCA + MIF; CBDCA + 134. Tumor area was measured by ultrasound weekly (D0-D28), and the ratio calculated relative to D0. Tumor growth curves were compared between arms for each PDX via a linear mixed effects regression test of coincident curves. Time to progression was also evaluated and will be presented. Results: In 1/5 models (PH160), CBDCA + MIF significantly suppressed tumor growth compared to CBDCA alone (p < 0.05, Table 1). Addition of 134 to CBDCA did not suppress tumor growth compared to CBDCA alone in any model. In the 2 models with no difference of CBDCA versus CTL (PH160, PH454), addition of a GR antagonist to CBDCA suppressed tumor growth versus CTL. Conclusions: Addition of GR antagonists can improve response to chemotherapy. Work is ongoing to identify the GR transcriptional network, tumor, and host characteristics which predict responses to GR antagonists. [Table: see text]

5510 Background: Single agent aromatase inhibitor (AI) therapy is associated with limited clinical activity in ovarian cancer (OC) and endometrial cancers (EC). AI therapy was associated with a progression free survival (PFS) at 12 weeks of only 20% in relapsed OC (Bowman et al, 2002) and a median PFS of 1 month in relapsed EC (Rose et al, 2000). In Estrogen Receptor (ER) positive metastatic breast cancer, clinical studies had shown a significant prolongation of PFS with the addition of the cyclin kinase 4/6 inhibitor ribociclib to AI (Hortobagyi et al, 2016). Here, we report the results of a phase 2 clinical trial of the combination of ribociclib and letrozole in patients with relapsed ER positive OC or EC. Objectives: Primary endpoint was the proportion of patients with relapsed ER positive OC or EC alive and progression-free after 12 weeks of therapy (PFS12) with the combination of ribociclib given at a dose of 400 mg orally daily and letrozole 2.5 mg orally daily. A PFS of 45% was considered a favorable result based on the data referenced above from Bowman et al. Methods: Eligibility criteria included patients with relapsed ER positive OC or EC, with measurable disease, not previously treated with ribociclib or AIs. Xenografts were created from CT guided tumor biopsies at baseline to assess feasibility. Results: A total of 40 patients were enrolled (20 with OC and 20 with EC) ) with a median age of 61 years (range: 30-82) and 64.5 (range: 52-75) in the OC and EC groups respectively. Among the OC patients, 17 had high grade serous carcinomas and 3 had low grade serous carcinomas. 11 EC patients had endometrioid cancers (3 with grade 1 tumors) and 9 had high grade serous tumors. Ten out of 20 OC patients and 11/20 EC patients were alive and progression-free at 12 weeks (PFS12 of 50 and 55%, respectively). The most common grade 3 or higher adverse events (occurring in at least 5 pts) were leukopenia (18%), lymphopenia (18%), neutropenia (13%), and fatigue (13%). 34 tumor biopsies were suitable for injection into mice and 44% engrafted. ER expression persisted through multiple passages in mice. Two of three EC PDX models exhibited improved PFS with letrozole/ribociclib compared to letrozole alone. Conclusions: The combination of ribociclib and letrozole is associated with a promising 50% and 55% PFS12 in patients with ER positive relapsed OC or EC respectively. Creation of xenograft tumor models from CT guided biopsies of OC and EC tumors was feasible. Clinical trial information: NCT02657928.

e17038 Background: Carcinosarcomas (CS) are aggressive gynecologic malignancies defined by a biphasic tumor histology of carcinomatous and sarcomatous components. High expression of glucocorticoid receptor (GR) is associated with aggressive tumor biology in triple-negative breast, ovarian, and endometrial cancers. GR activation results in transcriptional regulation of epithelial-mesenchymal transition (EMT) genes. Therefore, we hypothesized that the sarcomatous component of Müllerian CS may be associated with relatively higher GR expression compared to the carcinomatous portion. Methods: Müllerian CSs from the University of Chicago tissue bank diagnosed from 5/19/2009 – 8/25/2014 were identified and pathology confirmed (RL). In addition, we evaluated GR expression in a mouse PDX CS model. Immunohistochemical expression of nuclear estrogen (ER), progesterone (PR), androgen (AR), and GR was quantified using the H-score. Scores between the sarcomatous and carcinomatous components were compared using a paired t-test. Results: Mean GR H-score was relatively higher in the sarcomatous vs carcinomatous component, overall (144.44 vs 38.89, P = 0.0014). Mean H-score also differed between sarcomatous and carcinomatous components for ER (3.06 vs 63.06, P = 0.016), PR (1.67 vs 47.22, P = 0.004), and AR (0 vs 2.78, P = 0.056). The significantly higher sarcomatous GR expression was replicated in IHC evaluation of the mouse PDX model. Conclusions: GR expression is significantly higher in the sarcomatous than the carcinomatous component of Müllerian CS, while ER, PR, and AR expression is significantly lower. Recent data suggest that an EMT gene signature is more prominently expressed in the sarcomatous versus carcinomatous component. We hypothesize that GR expression and activity may mediate EMT gene expression and represent a therapeutic target for CS. [Table: see text]

Background Mammalian target of rapamycin (mTOR) represents a key downstream intermediate for a myriad of oncogenic receptor tyrosine kinases. In the case of the insulin-like growth factor (IGF) pathway, the mTOR complex (mTORC1) mediates IGF-1 receptor (IGF-1R)-induced estrogen receptor alpha (ERα) phosphorylation/activation and leads to increased proliferation and growth in breast cancer cells. As a result, the prevalence of mTOR inhibitors combined with hormonal therapy has increased in recent years. Conversely, activated mTORC1 provides negative feedback regulation of IGF signaling via insulin receptor substrate (IRS)-1/2 serine phosphorylation and subsequent proteasomal degradation. Thus, the IGF pathway may provide escape (e.g. de novo or acquired resistance) from mTORC1 inhibitors. It is therefore plausible that combined inhibition of mTORC1 and IGF-1R for select subsets of ER-positive breast cancer patients presents as a viable therapeutic option. Methods Using hormone-sensitive breast cancer cells stably transfected with the aromatase gene (MCF-7/AC-1), works presented herein describe the in vitro and in vivo antitumor efficacy of the following compounds: dalotuzumab (DALO; “MK-0646”; anti-IGF-1R antibody), ridaforolimus (RIDA; “MK-8669”; mTORC1 small molecule inhibitor) and letrozole (“LET”, aromatase inhibitor). Results With the exception of MK-0646, all single agent and combination treatment arms effectively inhibited xenograft tumor growth, albeit to varying degrees. Correlative tissue analyses revealed MK-0646 alone and in combination with LET induced insulin receptor alpha A (InsR-A) isoform upregulation (both mRNA and protein expression), thereby further supporting a triple therapy approach. Conclusion These data provide preclinical rationalization towards the combined triple therapy of LET plus MK-0646 plus MK-8669 as an efficacious anti-tumor strategy for ER-positive breast tumors. Electronic supplementary material The online version of this article (doi:10.1186/s12885-016-2847-3) contains supplementary material, which is available to authorized users.

A 51-year-old Somali man was admitted to an inpatient cardiology service at Saint Marys Hospital, a Mayo Clinic–affiliated hospital in Rochester, MN, with symptoms of fever and progressively worsening shortness of breath. Chest radiography demonstrated substantial pulmonary edema secondary to volume overload in the setting of acute worsening of chronic renal failure. Initial laboratory investigation yielded the following notable results (reference ranges provided parenthetically): leukocyte count, 30.3 × 109/L (3.5-10.5 × 109/L); blood urea nitrogen, 142 mg/dL (8-24 mg/dL); and creatinine, 12.6 mg/dL (0.9-1.4 mg/dL). Blood cultures were positive for Streptococcus pneumoniae in 4 of 6 specimens at 12.4 hours, and a nasal swab polymerase chain reaction was positive for H1N1 influenza. He underwent urgent dialysis, an intravenous antibiotic regimen of vancomycin and levofloxacin was initiated, and his clinical status was stabilized. His current presentation was complicated by a more than 10-year history of type 2 diabetes mellitus with poor control (glycated hemoglobin, 9.1% [4.0%-6.0%] at admission and 12.7% 1 year previously despite insulin therapy) and end-organ damage, including proliferative retinopathy, neuropathy, and nephropathy. His medical regimen consisted of the aforementioned antibiotics, scheduled dialysis, insulin therapy, and prophylactic heparin. The next 7 days of his hospitalization were unremarkable, with anticipated discharge on hospital day 8.

The insulin-like growth factor pathway plays a major role in cancer cell proliferation, survival and resistance to anti-cancer therapies in many human malignancies, including breast cancer. As a key signaling component of IGF system, the IGF-1 receptor is the target of several investigational agents in clinical and pre-clinical development. This review will focus on the rationale for targeting the IGF-1 receptor and other components of the IGF-1 system. In addition, we will examine the role of IGF-1 signaling in resistance to clinically important breast cancer therapies, including cytotoxic chemotherapy, hormonal therapy and erbB targeted agents. We will also review the completed and ongoing clinical investigations with IGF-1 receptors inhibitors to date and the utility of these early data in designing future breast cancer studies with IGF-1 signaling inhibition strategies.

Ovarian cancer is the most lethal gynecologic cancer and the fifth most common cause of cancer death among women in the United States. Although there have been incremental improvements in progression free survival over the last several decades from advances in surgical technique and combination-chemotherapy strategies, overall survival has essentially remained unchanged. Although novel therapeutics have the potential to impact overall survival and lead to more cures, drug development in this area has been limited by the availability of clinically relevant models that recapitulate the molecular and phenotypic characteristics of primary ovarian cancers. To overcome this barrier, we have developed primary patient derived xenograft (PDX) models from every consenting patient having primary debulking surgery at Mayo Clinic since 2010 (>550 unique patients). Fresh tissues are minced and injected intraperitoneally into severe combined immunodeficient (SCID) mice without enzymatic digestion or surgical implantation. The patient-to-mouse time is typically Ovarian PDX models have demonstrated their utility as patient surrogates. The histologic diversity is representative of the population from which they are derived with high-grade serous comprising most of the models. However, the ovarian PDX bank also includes less-common subtypes, such as clear cell, mucinous, and carcinosarcoma. Histologic and genomic fidelity is maintained within early-passage tumors. Moreover, the patient's clinical response to carboplatin and paclitaxel (a standard front-line therapy for ovarian cancer) demonstrates high correlation to the matched PDX tumor response in vivo, supporting their relevance as patient surrogates. The models have been used for preclinical drug development and biomarker validation. One example is the correlation between PARPi response in PDXs and their homologous recombination deficiency (HRD) score. All models with a low HRD score, Ovarian PDXs are also being used to direct patient care in a clinical trial setting at all three Mayo Clinic sites (MN, FL, and AZ). Tumors are collected at the time of debulking surgery for heterotransplantation. Subsequent xenografts are treated with standard first-line chemotherapy, similar to their matched patient in the clinic, and then PDXs are treated with standard ovarian cancer second-line therapies: liposomal doxorubicin, topotecan, gemcitabine, and paclitaxel. When patients develop platinum-resistant recurrent cancer, the chemotherapy response in the PDX is used to direct therapy in the clinic. Many challenges continue for ovarian cancer PDX models. The use of immunocompromised mice limits the ability to study the involvement of immunity in chemotherapy responsiveness. In addition, these models are not ideal for testing novel immunotherapies, such as the immune check point inhibitors. Further work to overcome these and other limitations are needed. Citation Format: S. John Weroha. Ovatars in preclinical drug development and clinical trial for ovarian cancer patients. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr IA11.

Insulin-like growth factor (IGF) plays an important role in tissue growth and development. Several studies have demonstrated the association between circulating levels of IGF-1 and -2 and cancer risk, and the IGF system has been implicated in the oncogenesis of essentially all solid and hematologic malignancies. The optimal strategy for targeting IGF signaling in patients with cancer is not clear. The modest benefits reported thus far underscore the need for a better understanding of IGF signaling, which would enable clinicians to identify the subset of patients with the greatest likelihood of attaining benefit from this targeted approach.

Objective Resistance to chemotherapy is a major challenge in the treatment of ovarian/peritoneal cancer. One purported mechanism of topotecan resistance is the breast cancer resistance protein (BCRP) and P-glycoprotein (Pgp). We designed a phase II clinical trial evaluating the efficacy and adverse event profile of concomitant topotecan and lapatinib, a small molecule pan-erbB inhibitor that can block BCRP/Pgp efflux of topotecan. Methods Patients with platinum-refractory or resistant epithelial ovarian/peritoneal cancer were treated with topotecan 3.2mg/m2 IV on Day 1, 8 and 15 and lapatinib 1250mg PO daily, continuously in 28day cycles. The primary endpoint was response rate. For correlative studies, archived tissue was assessed for expression of EGFR, HER2, HIF-1α, CD31, and BCRP. Results Eighteen patients were enrolled and treated. Four experienced evidence of clinical benefit: one partial response and three with stable disease. Using a two-stage Simon design, the trial was stopped after the first stage due to insufficient activity. Grades 3+ and 4+ adverse events (AE) were experienced in 14 and 4 patients, respectively. The most common grade 3/4 AE were neutropenia (56%), thrombocytopenia (28%), and diarrhea (22%). Conclusions The combination of lapatinib plus topotecan for the treatment of platinum refractory/resistant epithelial ovarian cancer lacks sufficient activity to warrant further investigation. In particular, hematologic adverse events were substantial. Expression of correlative study markers did not reveal patterns of predicted benefit or toxicity. Disruption of erbB signaling and BCRP/Pgp efflux with lapatinib was insufficient for overcoming topotecan resistance, suggesting alternative mechanisms of resistance are involved.

Ovarian cancer is the most lethal gynecologic malignancy and the fifth leading cause of cancer deaths among women. The current standard of care post surgical cytoreduction is combination platinum/taxane chemotherapy. The initial response varies widely; subsets of carcinomas demonstrate resistance or sensitivity from the onset. The underlying cause of this response heterogeneity remains incompletely understood. Patient-derived xenografts (PDX) serve as useful in vivo models to study molecular response markers and test the efficacy of targeted therapies. Our group has demonstrated a high engraftment rate (>70%) of ovarian cancer PDXs (Avatars) by injecting treatment naïve patient tumor directly into the peritoneal cavity of an in immunocompromised mouse host in an effort to better mimic the anatomic context by which ovarian cancer naturally develops. We now have 328 engrafted Avatar models representing the wide range of ovarian cancer subtypes, including serous (65%), mixed epithelial (10%), endometrioid (7%), clear cell (4%), mucinous (3%), carcinosarcoma (1%) and other (10%). Using these models, we are performing a massively parallel sequencing strategy referred to as BROCA-HR to detect all mutation classes (e.g. gene rearrangements, copy number variations, etc.) and gene aberrations within the Fanconi Anemia-BRCA homologous recombination (HR), non-homologous end joining (NHEJ), PTEN, and DNA Mismatch repair pathways. To date, 148 Avatar models have undergone BROCA sequencing. Observed deleterious mutations included 12 BRCA1 (8%), 6 BRCA2 (4%), and 4 PIK3CA (3%); additional loss of function mutations were also evident in the following genes: ATM, RAD51C, FANCM, FANCD2, FANCA, CHEK2, PALB2, MHS6, CDK12 and GEN1. These models are representative of mutations seen in the TCGA mutation set. Models harboring said mutations are currently being tested with platinum agents and/or PARP inhibitors. Taken together, the Avatars represent a high throughput model system for pre-clinical testing in vivo that effectively recapitulates ovarian cancer (e.g. mutations in BRCA1, BRCA2 and other DNA damage response proteins). We have been able to establish avatars at a high rate, including those with mutations in BRCA1, BRCA2 and other DNA damage response genes. These models will be a unique resource for future studies of biomarkers and novel therapeutic approaches. This work is funded by the Ovarian Cancer Research Fund (750563), Mayo Ovarian SPORE (CA136393), National Cancer Institute (RO1 CA184502). Note: This abstract was not presented at the meeting. Citation Format: Kunal A. Lodhia, Marc A. Becker, Xiaonan Hou, Kimberly R. Kalli, Maria I. Harrell, Elizabeth M. Swisher, John S. Weroha, Paul Haluska. Characterization of 148 ovarian cancer tumografts (Avatars) using BROCA-HR deep sequencing. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1474. doi:10.1158/1538-7445.AM2015-1474

Purpose: The therapeutic potential of PARP inhibitors is predicted to extend beyond BRCA mutant phenotypes to homologous recombination (HR)-deficient cancers. Response of individual ovarian cancers to niraparib was characterized using treatment naïve, patient-derived tumorgraft models and correlated with predicted HR status and gene expression profile. Methods: Utilizing a living tumor bank of patient-derived ovarian xenografts (PDXs), niraparib (MK-4827) was evaluated in five high-grade ovarian cancer tumorgrafts (PDX077, PDX087, PDX039, PDX080 and PDX95) as monotherapy, combination with carboplatin ± paclitaxel and maintenance therapy. Intraperitoneal tumorgrafts were monitored for tumor growth with twice-weekly transabdominal ultrasound imaging. In vivo response to niraparib was correlated to massively parallel sequencing data (BROCA) for HR genes and with each source patient's platinum response. Tumorgrafts were accordingly classified into predicted HR-proficient and HR-deficient phenotypes. PARP1 and poly(ADP-ribose) polymer (pADPr) expression as well as gene expression by DNA microarray were compared between treatment and control tumor replicates, and HR-deficient vs. HR-proficient tumors. Results: PDX077 (verified to harbor a somatic BRCA2 mutation (predicted HR deficient)) and PDX039 without any HR mutations detected by BROCA (predicted HR proficient) both responded to niraparib monotherapy and combination therapy in vivo (p=0.002 and 0.009 for treated vs. control groups, respectively). Significant growth attenuation, but not regression, in response to single agent treatment was demonstrated in PDX080 (CDK12 mutation; predicted HR-deficient; p=0.02 vs. control). In comparison, a BRCA2-mutant model (PDX095) failed to respond to niraparib monotherapy (p=0.97). As predicted, niraparib was not active as a single agent or in combination with chemotherapy in a BRCA wild-type, predicted HR-proficient tumorgraft (PDX087; p=not significant). Niraparib enhanced tumor regression with carboplatin but not with paclitaxel/carboplatin in an HR-deficient tumorgraft (PDX077), and maintenance niraparib therapy was effective in prolonging recurrence-free survival. pADPr inhibition was demonstrated in all niraparib-treated tumorgrafts, while PARP1 degrada-tion was evident in tumorgrafts responsive to single agent niraparib. Differential gene expression was seen in niraparib treated vs. control tumors in HR-deficient tumorgrafts in comparison to HR-proficient tumors at the end of 4 weeks of treatment. Clustering of 6 most/least differentially expressed genes was predictive of response to niraparib. Furthermore, RAD51C and PTEN gene expression were diminished in PDX039 (HR proficient by BROCA; niraparib responsive), suggesting a possible mechanism for its sensitivity to niraparib. Conclusion: Response to niraparib was seen in both BRCA-mutant and BRCA-wildtype xenografts. Thus, BRCA or HR gene mutational status alone was not sufficient to predict response to niraparib. Low RAD51C, PTEN and loss of PARP1 expression following treatment were most characteristic of tumors responding to niraparib. Paclitaxel may be detrimental to the sensitizing effects of PARP inhibition on carboplatin, which may have clinical implications for the incorporation of PARP inhibitors in front-line treatment. Our data are supportive of the phase III study of niraparib as maintenance therapy in patients with platinum-sensitive ovarian cancer. This abstract is also presented as Poster A30. Citation Format: Mariam Al Hilli, S. John Weroha, Marc Becker, Xiaonan Hou, Sean Harrington, Sarah McKinstrey, Kimberly Kalli, Karin Goodman, Keith Wilcoxen, Elizabeth Swisher, Scott Kaufmann, Paul Haluska. In vivo antitumor activity of the PARP inhibitor niraparib (MK-4827) in homologous recombination deficient and proficient ovarian cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr PR05.

Despite advances in chemotherapeutic options over the last four decades, ovarian cancer remains the most lethal gynecologic malignancy with a cure rate that is essentially unchanged. A major barrier is lack of treatment-naïve, clinically- relevant in vivo models of epithelial ovarian cancer (EOC). To target this problem, we have developed low-passage in vivo models of EOC derived from patient primary debulking procedures at Mayo Clinic (Rochester, MN). Tumors were obtained from consented patients with suspected ovarian cancer, minced and injected into severe combined immunodeficiency (SCID) mice intraperitoneally for model establishment. To the date, we have heterotransplanted 129 EOC or ovarian malignant mixed mullerian (MMMT) tumors. The most common histologic subtype is serous (70.5%), followed by endometrioid (12.4%), clear cell (6.9%), and others (9.9%). The tumors were injected intraperitoneally into severe combined immunodeficiency (SCID) mice and the average time to moribund (TTM) was 174 +/− 83 days. In general, tumors grew faster with serial passages, TTM for epithelial tumors was 87 +/− 15 days and 19.5 +/− 3 days for MMMT. De novo ascites developed in 17 models and 24 models developed bowel metastasis, two clinically-relevant complications in late-stage ovarian cancer patients. Tumorgrafts were histologically similar to their source patient tumors and were positive for expression epithelial markers (pan-cytokeratin). The engraftment rate was 72.4% (n=87) after ≤ 6 months of lead-time, which is the average time to tumorgraft harvest. Passage of well-established tumorgrafts in SCID mice was successful in 88.6 % (n= 70) of all mice but only 56% (n=16) of athymic nude mice, consistent with prior studies demonstrating improved engraftment rates in more immunodeficient mice. Molecular characterization of tumorgrafts by array comparative genomic hybridization revealed similar gains and losses between the patient, early-passage, and later-passage tumorgraft tissues, indicating the tumorgrafts were genetically similar to their primary tumor. Analysis of tumorgrafts using the Affymetrix Human Plus 2.0 arrays revealed a predominance of previously described molecular subtypes C3, C4, and C5. Current investigations with both standard chemotherapy and novel targeted therapies are ongoing. Taken together, these models are as diverse as the patient population from which they are derived, produce clinically-relevant complications of EOC, maintain genetic fidelity in SCID mice, and are useful preclinical models for testing and development of novel therapeutics for ovarian cancer. High rates of engraftment are feasible. These tumorgrafts may help define predictors of response and eventually, lead to better treatments for patients. This work is funded by the Mayo Ovarian SPORE (CA136393) and the Minnesota Ovarian Cancer Alliance. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3274. doi:1538-7445.AM2012-3274