The association of histopathologic features after neoadjuvant chemo-immunotherapy with clinical outcome: Sub-analyses from the randomized double-blinded, placebo-controlled, Phase III IMagyn050/GOG3015/ENGOT-ov39 study

OBJECTIVE

Histopathologic characteristics after neoadjuvant chemotherapy (NACT) may correlate with outcome. This study evaluates histopathologic features after immunotherapy and NACT/bevacizumab, and associated clinical outcomes.

METHODS

Evaluable tissue from IMagyn050/GOG3015/ENGOT-ov39 patients from prespecified anatomic sites from interval cytoreductive surgery (ICS) after NACT/bevacizumab plus atezolizumab/placebo underwent central histopathologic scoring and analyzed with clinical outcomes.

RESULTS

The predefined population had 243 evaluable NACT patients, with 48.1% tumors being PD-L1-positive. No statistically significant differences in PFS (16.9 months vs. 19.2 months, p = 0.21) or OS (41.5 months vs. 45.1 months, p = 0.67) between treatment arms were seen. Substantial residual tumor (RT) (3+) was identified in 26% atezolizumab vs. 24% placebo arms (p = 0.94). Most showed no (1+) necrosis (82% vs. 96%, respectively, p = 0.69), moderate (2+) to severe (3+) fibrosis (71% vs. 75%, respectively, p = 0.82), and extensive (2+) inflammation (53% vs. 47% respectively, p = 0.48). No significant histopathologic differences were identified by tissue site or by arm. Multivariate analyses showed increased risk for progression with moderate and substantial RT (13.6 mon vs. 21.1 mon, hazard ratio 2.0, p < 0.01; 13.6 mon vs. 21.1 mon, HR 1.9, p < 0.01, respectively); but decreased risk for death with extensive inflammation (46.9 mon vs. 36.3 mon, HR 0.65, p = 0.02). Inflammation also correlated with greater likelihood of response to NACT/bevacizumab plus immunotherapy (odds ratio 2.9, p < 0.01). Modeling showed inflammation as a consistent but modest predictor for OS.

CONCLUSIONS

Detailed histologic assessment of ICS specimens appear to identify characteristics, such as inflammation and residual tumor, that may provide insight to certain clinical outcomes. Future work potentially leveraging emerging tools may provide further insight into outcomes.

Identification of BRCA1/2 mutation female carriers using circulating microRNA profiles

Identifying germline BRCA1/2 mutation carriers is vital for reducing their risk of breast and ovarian cancer. To derive a serum miRNA-based diagnostic test we used samples from 653 healthy women from six international cohorts, including 350 (53.6%) with BRCA1/2 mutations and 303 (46.4%) BRCA1/2 wild-type. All individuals were cancer-free before and at least 12 months after sampling. RNA-sequencing followed by differential expression analysis identified 19 miRNAs significantly associated with BRCA mutations, 10 of which were ultimately used for classification: hsa-miR-20b-5p, hsa-miR-19b-3p, hsa-let-7b-5p, hsa-miR-320b, hsa-miR-139-3p, hsa-miR-30d-5p, hsa-miR-17-5p, hsa-miR-182-5p, hsa-miR-421, hsa-miR-375-3p. The final logistic regression model achieved area under the receiver operating characteristic curve 0.89 (95% CI: 0.87-0.93), 93.88% sensitivity and 80.72% specificity in an independent validation cohort. Mutated gene, menopausal status or having preemptive oophorectomy did not affect classification performance. Circulating microRNAs may be used to identify BRCA1/2 mutations in patients of high risk of cancer, offering an opportunity to reduce screening costs.

Abstract 5702: Ovarian cancer tumor microenvironment and atezolizumab (atezo) clinical activity: IMagyn050 sub-study

Background: Tumor biomarkers such as CD8 density and location (i.e., immune inflamed phenotype) and immune rich molecular subtype have been linked to immune checkpoint blockade (ICB) overall survival (OS) in different cancers. The IMagyn050 trial (NCT03038100), which evaluated the efficacy of Atezo vs placebo (Pla) with carboplatin, paclitaxel and bevacizumab (CPB) in front line ovarian cancer patient (pts), did not meet its co-primary endpoints of PFS in ITT or PD-L1+ (Moore et al. JCO 2021). In the current IMagyn050 substudy we assessed potential predictive tumor immune biomarkers for Atezo clinical benefit.

Methods: FFPE tumors from the biomarker evaluable population were tested for PD-L1 IHC, CD8/PanCK IHC (total CD8 T cells and immune location phenotypes [inflamed, excluded, desert]) and RNA-seq (to derive molecular subtypes, biological pathways and cellular components [xCELL]) in tissue from baseline (n=860), on-treatment (OT, 9 weeks, n=233), intra- (n=8) and inter-lesion (n=12) matched samples. Hazard ratio (HR) interaction test from multivariate adjusted Cox-regression analysis for PFS and OS was performed to test predictive biomarkers.

Results: While tumors with CD8 T cells, immunoreactive molecular subtypes or immune inflamed phenotype were enriched for PD-L1+, only pts with immune inflamed tumors showed improved OS Atezo benefit (HR 0.67). Improved Atezo PFS/OS benefit was also observed in pts with whose tumors had high oxidative phosphorylation (OXPHOS, HR: 0.72/0.65) and UV Response (UV, HR: 0.64/0.58) but not IFNγ response. Plasma B cells were linked to improved OS Atezo benefit vs Pla (HR 0.53). We leveraged OT samples from pts in the neoadjuvant cohort to assess treatment effect on the tumor microenvironment. Analyses showed that CPB reduced tumor proliferation and increased tumor immune inflammation (CD8 T cells, PD-L1 and IFNα/IFNγ response), further increased by Atezo. Immune inflammation is challenging in ovarian cancer due to extensive tumor heterogeneity. Prevalence of tumor biomarkers varied by anatomic locations: total CD8, CD8 localization and molecular subtypes. Inter- and intra-lesion biomarker status within the same pt showed PD-L1 and plasma B cells as most consistent. Molecular subtypes and immune phenotypes had moderate intra-lesion agreement but discordant between lesions. PD-L1 and OXPHOS were the only biomarkers linked to Atezo benefit regardless of anatomical location.

Conclusion: This comprehensive exploratory study suggests that DNA damage, OXPHOS, plasma B cells and immune inflamed tumors, but not molecular subtypes or total CD8 T cells, may predict Atezo + CPB OS. This treatment promotes immune inflammation in OC tumors. Notably, we found that several biomarkers are highly heterogeneous. Our findings highlight the challenges of achieving durable clinical benefit from targeted immunotherapy in ovarian cancer pts.

Citation Format: Venkatesh Krishnan, Ching-Wei Chang, Habib Hamidi, Michael A. Bookman, Charles Landen, Tashanna Myers, Hiroaki Kajiyama, Sakari Hietanen, Lyndsay Willmott, Premal Thaker, Cagatay Taskiran, Jalid Sehouli, Victor Khor, Yvonne Lin Liu, Sandro Pignata, Kathleen Moore, Luciana Molinero. Ovarian cancer tumor microenvironment and atezolizumab (atezo) clinical activity: IMagyn050 sub-study. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5702.

A Pan-ALDH1A Inhibitor Induces Necroptosis in Ovarian Cancer Stem-like Cells

Ovarian cancer is typified by the development of chemotherapy resistance. Chemotherapy resistance is associated with high aldehyde dehydrogenase (ALDH) enzymatic activity, increased cancer "stemness," and expression of the stem cell marker CD133. As such, ALDH activity has been proposed as a therapeutic target. Although it remains controversial which of the 19 ALDH family members drive chemotherapy resistance, ALDH1A family members have been primarily linked with chemotherapy resistant and stemness. We identified two ALDH1A family selective inhibitors (ALDH1Ai). ALDH1Ai preferentially kills CD133+ ovarian cancer stem-like cells (CSCs). ALDH1Ai induce necroptotic CSC death, mediated, in part, by the induction of mitochondrial uncoupling proteins and reduction in oxidative phosphorylation. ALDH1Ai is highly synergistic with chemotherapy, reducing tumor initiation capacity and increasing tumor eradication in vivo. These studies link ALDH1A with necroptosis and confirm the family as a critical therapeutic target to overcome chemotherapy resistance and improve patient outcomes.

Perineal colostomy prolapse: a novel application of mesh sacral pexy

Full thickness colonic prolapse following pseudocontinent perineal colostomy has not been previously reported. Possible contributing factors include a large skin aperture at the site of the perineal stoma, the absence of anal sphincters and mesorectal attachments and the presence of a perineal hernia. A novel application of sacral pexy combined with perineal hernia repair using two prosthetic meshes is described.

How to deal with hepatic artery injury during pancreaticoduodenectomy. A systematic review

BACKGROUND

Operative injury to the hepatic artery is a serious complication of pancreaticoduodenectomy and guidelines to manage this complication are lacking.

METHODS

A systematic search performed in PubMed database identified eleven studies overall including 20 patients having sustained injury to the hepatic artery during pancreaticoduodenectomy (n=18) or total pancreatectomy (n=2). One further unpublished personal observation following pancreaticoduodenectomy was also included.

RESULTS

Sixteen of 21 patients (76%) experienced serious complications including liver necrosis/abscess (n=14), acute liver failure (n=3), and biliary anastomotic dehiscence (n=6). Eleven patients (52%) were reoperated and 5 patients died (24%). Arterial injury was recognized and repaired immediately in five patients, four recovering uneventfully and one dying from acute liver failure (20%). In contrast delayed or conservative treatment in 16 patients was associated with serious early morbidity in 15 patients (94%), leading to death in 4 patients and late biliary complications in four others.

CONCLUSIONS

Accidental interruption of arterial flow to the liver during pancreaticoduodenectomy often results in serious short and long-term consequences. Immediate restoration of arterial flow is indicated whenever technically feasible and may prevent early life-threatening complications as well as late biliary stenosis.

Abstract POSTER-THER-1402: Overcoming platinum resistance in ovarian cancer with niclosamide

Objective: Niclosamide, a salicyclamide derivative and FDA approved teniacide, exhibits potent effects against ovarian cancer in vitro by inhibiting the Wnt/β-catenin, STAT3, and mTOR pathways. Unfortunately, its low bioavailability as a chemotherapeutic agent in vivo necessitates investigation of analogs with improved pharmacokinetics and pharmacodynamics. The objective of this study was to investigate the role of targeting the Wnt/β-catenin and STAT3 pathways with niclosamide and niclosamide analogs (C-11 and C-32) in platinum-sensitive and -resistant ovarian cancer cell lines, primary ovarian cancer ascites cell populations, and tumor tissues. In addition, carboplatin and/or LLL12, a novel STAT3 inhibitor effective against ovarian cancer, were used in combination with niclosamide and its analogs to test for synergistic cytotoxicity. Methods: Two ovarian cancer cell lines A2780, SKOV3ip1 and their chemo-resistant derivatives, A2780.cp20 and SKOV3ip2.TRip2, were treated with niclosamide or C-11 or C-32 (0.1 to 5 μM) alone or in combination with carboplatin (5 to 150 μM) or LLL12 (0.1 nM - 10 µM). Tumorspheres were isolated from the ascites of ovarian cancer patients who underwent surgery. Tumor slices were prepared from freshly obtained ovarian cancer specimens. ATPLite assay was performed to measure cytotoxicity in cell lines, tumorspheres, and tumor slices. Western blot was used to assess expression of proteins implicated in the Wnt, mTOR, and STAT3 pathways. β-catenin signaling activity was measured using the TOPflash reporter assay. Results: All four cell lines were sensitive to niclosamide, C-11, and C-32 with similar IC50 values. Additive cytotoxicity was seen when niclosamide or its analogs were combined with carboplatin or LLL12 in the cell lines, tumorspheres, and tumor tissues. Ex vivo and in vitro samples from the same patient demonstrated similar cytotoxicity with niclosamide, C-11, and C-32 treatment. Synergism was also seen between carboplatin and LLL12 in vitro. The TOPflash assay showed that the combination of niclosamide (0.4 μM) and LLL12 (0.25 μM) decreased β-catenin activity more than either agent alone, suggesting that there is crosstalk between the STAT3 and Wnt/β-catenin pathways. Wnt/β-catenin, STAT3, and mTOR pathway target proteins (LRP6, pLRP6, Axin2, and Survivin) were downregulated with niclosamide and C-32 treatment, and to a greater degree with C-11. Conclusion: Combination treatment with niclosamide, or its analogs, with carboplatin or LLL12 induced greater cytotoxicity than either agent alone in ovarian cancer cell lines, primary tumorspheres, and tumor slices. The synergistic cytotoxicity seen in platinum-resistant cell lines with niclosamide, or its analogs, in combination with carboplatin suggest that targeting the Wnt/ β-catenin and STAT3 pathways may prove effective in overcoming chemoresistance in patients with platinum resistant ovarian cancer.

Citation Format: Rebecca C. Arend, MD, Abhishek Gangrade, Christen L. Walters Haygood, MD, Chandrika Kurpad, Brandon J. Metge, Rajeev S. Samant, PhD, Pui-Kai Li, PhD, Yonghe Li, PhD, Deepak Bhasin, PhD, Charles Landen, MD, Ronald Alvarez, MD, J. Michael Straughn, MD, Donald J. Buchsbaum, PhD. Overcoming platinum resistance in ovarian cancer with niclosamide [abstract]. In: Proceedings of the 10th Biennial Ovarian Cancer Research Symposium; Sep 8-9, 2014; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(16 Suppl):Abstract nr POSTER-THER-1402.

Epithelial ovarian cancer: An overview

Ovarian cancer is the second most common gynecological cancer and the leading cause of death in the United States. In this article we review the diagnosis and current management of epithelial ovarian cancer which accounts for over 95 percent of the ovarian malignancies. We will present various theories about the potential origin of ovarian malignancies. We will discuss the genetic anomalies and syndromes that may cause ovarian cancers with emphasis on Breast cancer type 1/2 mutations. The pathology and pathogenesis of ovarian carcinoma will also be presented. Lastly, we provide a comprehensive overview of treatment strategies and staging of ovarian cancer, conclusions and future directions.

Platinum-sensitive recurrence in ovarian cancer: the role of tumor microenvironment

Despite several advances in the understanding of ovarian cancer pathobiology, in terms of driver genetic alterations in high-grade serous cancer, histologic heterogeneity of epithelial ovarian cancer, cell-of-origin for ovarian cancer, the survival rate from ovarian cancer is disappointingly low when compared to that of breast or prostate cancer. One of the factors contributing to the poor survival rate from ovarian cancer is the development of chemotherapy resistance following several rounds of chemotherapy. Although unicellular drug resistance mechanisms contribute to chemotherapy resistance, tumor microenvironment and the extracellular matrix (ECM), in particular, is emerging as a significant determinant of a tumor’s response to chemotherapy. In this review, we discuss the potential role of the tumor microenvironment in ovarian cancer recurrence and resistance to chemotherapy. Finally, we propose an alternative view of platinum-sensitive recurrence to describe a potential role of the ECM in the process.

BRCA1 proteins regulate growth of ovarian cancer cells by tethering Ubc9

Mutation in the BRCA1 gene is associated with increased risk for hereditary breast and ovarian cancers. In sporadic ovarian tumors, BRCA1 dysfunction is thought to be common. BRCA1 is a nuclear-cytoplasm shuttling protein. Our group has previously reported that BRCA1 proteins, unlike K109R and cancer-predisposing mutant C61G BRCA1 proteins, bind the sole SUMO E2-conjugating enzyme Ubc9. In this study, we examined the result of altered Ubc9 binding and knockdown on the sub-cellular localization and growth inhibitory function of BRCA1 proteins in ovarian cancer cells. Using live imaging of YFP, RFP-tagged BRCA1 and BRCA1a proteins, our results show enhanced cytoplasmic localization of K109R and C61G mutant BRCA1 proteins in ES-2, NIHOVCAR3 and UWB 1.289 ovarian cancer cells. Down-regulation of Ubc9 in ovarian cancer cells using Ubc9 siRNA resulted in cytoplasmic localization of BRCA1 and BRCA1a proteins. These mutant BRCA1a proteins were impaired in their capacity to inhibit growth of ES-2 ovarian cancer cells. Several ovarian cancer cells, including a BRCA1-null ovarian cancer cell line, showed higher levels of expression of Ubc9. This is the first study demonstrating the physiological link between loss of Ubc9 binding and loss of growth suppression of disease-associated mutant BRCA1a proteins in ovarian cancer cells. BRCA1, by turning off or on Ubc9 binding, regulates growth of ovarian cancers.

Abstract 1649: The E3 ubiquitin ligase EDD regulates platinum resistance and is a novel therapeutic target for epithelial ovarian cancer

Introduction: Ovarian cancer is treated with a combination of surgery and chemotherapeutics, including taxol and platinum agents. A major difficulty in eradicating these tumors is the selection of drug resistant cells. EDD (E3-ubiquitin ligase identified by Differential Display) is a 300 kDa E3 ubiquitin ligase that is overexpressed in 84% of recurrent, platinum-resistant ovarian cancers, but is rare in benign in borderline tumors. This correlation with chemoresistance suggests that EDD may be involved in mediating platinum resistance and/or tumor survival.

Experimental Procedures: EDD protein knockdown was accomplished using siRNA (small interfering RNA) and shRNA (short hairpin RNA) for transient or stable knockdown, respectively, in ovarian cancer cell lines. Apoptosis and sensitivity to cisplatin were measured using MTS assay, propidium iodide staining, and western blotting for PARP and caspase 3 cleavage. Cisplatin resistance by EDD overexpression was determined by transient transfection of GFP, FLAG-EDD or the ubiquitin ligase deficient FLAG-EDD-C2768A into COS-7 cells followed by cisplatin treatment and apoptosis measurement in transfected cells by the TACS 2 TdT-Blue Label Kit followed by microscopy. Mice with intraperitoneal xenografts of ES2 and A2780ip2 cells were treated once weekly with cisplatin and twice weekly with control or EDD siRNA.

Results: EDD was overexpressed in 5 of 7 ovarian cancer cell lines compared to benign IOSE cells. EDD overexpression in COS-7 cells was sufficient to protect from cisplatin-induced apoptosis and the induced resistance was dependent upon EDD ubiquitin ligase activity (relative apoptosis: GFP = 1; EDD = 0.42, EDD-C2768A = 1.23). Stable knockdown of EDD increased cisplatin sensitivity in ES2 cells (IC50 = 37 μM for control, 9 μM for EDD shRNA). EDD siRNA alone induced cleavage of PARP and caspase 3 compared to control siRNA and enhanced cleavage of both in the presence of cisplatin. Mouse xenograft studies demonstrated that nanoliposomal delivery (DOPC) of EDD siRNA showed a trend towards reduced tumor compared to control siRNA. In vivo, mice treated with EDD siRNA by nanoliposomal delivery (DOPC) had a trend towards less tumor than those treated with control siRNA (27.7% reduction in ES2, 42.5% in A2780ip2, p = 0.23 and 0.19 respectively). Mice treated with combined EDD siRNA and cisplatin had significantly less tumor than controls (77.9% reduction in ES2, 75.9% in A2780ip2, p = 0.004 and 0.042, respectively) and cisplatin alone (60.3-64.4% reduction, p = 0.035).

Conclusions: EDD overexpression is sufficient to promote cisplatin resistance, dependent upon its E3 ubiquitin ligase activity. Targeting EDD expression induces apoptosis and cisplatin. sensitivity in vitro and in vivo. Targeting EDD may be an effective treatment for platinum-resistant ovarian cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1649. doi:10.1158/1538-7445.AM2011-1649

Complement-mediated mechanisms in anti-GD2 monoclonal antibody therapy of murine metastatic cancer

The role of complement in antibody therapy of cancer is in general poorly understood. We used the EL4 syngeneic mouse model of metastatic lymphoma to investigate the role of complement in immunotherapy directed against GD2, a target of clinical relevance. IgG2a and IgM anti-GD2 therapy protected EL4-challenged mice from metastases and prolonged survival. Expression of CD59, an inhibitor of direct complement-mediated cytotoxicity (CMC), effectively protected EL4 cells from CMC in vitro but did not affect the outcome of monoclonal antibody therapy. Protection by IgG therapy was also unaffected in mice deficient in C3 or complement receptor 3 (CR3) but was almost completely abrogated in FcgammaR I/III-deficient mice. These data indicate a crucial role for antibody-dependent cell-mediated cytoxicity (ADCC). However, at lower doses of IgG, therapeutic effect was partially abrogated in C3-deficient mice, indicating complement-mediated enhancement of ADCC at limiting IgG concentration. In contrast to IgG, the therapeutic effect of IgM was completely abrogated in C3-deficient mice. High level expression of CD59 on EL4 did not influence IgM therapy, suggesting IgM functions by complement-dependent cell-mediated cytotoxicity (CDCC), a mechanism thought to be inactive against tumor cells. Thus, IgG and IgM can operate via different primary mechanisms of action, and CDCC and complement-dependent enhancement of ADCC mechanisms are operative in vivo. The effects of complement can be supplemental to other antibody-mediated mechanisms and likely have increased significance at limiting antibody concentration or low antigen density.