Abstract 2172: NLRP3 inflammasome targeting to overcome platinum and PARPi resistance by modulating cancer related inflammation in ovarian cancer

Abstract Background: Under chronic conditions, NLRP3 inflammasome acts as instigator of pathological inflammation causing inflammation-induced carcinogenesis. Despite killing the cancer cells and being primary treatment modalities, platinum and PARPi regimen activate NLRP3 inflammasome that drives the cancer-promoting inflammatory and immunosuppressive environment and promotes inflammation-associated tumor progression ultimately contributing to resistance and therapy failure. We hypothesize that combining NLRP3 inhibitor (NLRP3i)/IL-1β inhibitor (IL-1βi) to platinum agent and PARPi can improve their anti-tumor activity by modulating inflammation associated ovarian cancer (OvCa) and overcoming resistance in pre-clinical OvCa models. Methods: The cytotoxicity of the drugs, platinum agent (cisplatin), PARPi (olaparib), NLRP3i (MCC950) and IL-1βi (AS101) as single agent and in combination against human OvCa cells (UWB1.289.BRCA1, OVCAR-3, PEO-1 and PEO-4) was analyzed by MTT assay and drug synergism was evaluated by combination index. qPCR, flow cytometry, multiplex immunoassay and immunoblot analysis were performed in human OvCa cells co-cultured with primary human blood monocytes and the human monocytic cell line (THP-1). Statistical significance was determined by two-tailed Student’s t test. p<0.05 were considered statistically significant. Results: The drug combination showed synergistic enhanced anticancer activity by apoptosis induction and cancer cell proliferation inhibition. Platinum agent and PARPi was associated with upregulation of inflammasome downstream genes, IL-1β, IL-6 and CCL2 in OvCa cells indicating NLRP3 activation. There was a significant decrease in NLRP3, IL-1β, IL-6 and CCL2 levels in combination groups indicating that NLRP3 blockade can delay OvCa cell growth by alleviating immunosuppressive and inflammatory microenvironment. Combination treatment polarized M2 macrophages by downregulating M2-related markers, CCR2, ARG1, CD163 and CD206 towards the M1 phenotype by upregulating M1-related markers, iNOS, CD86 and CXCL10 suggesting that NLRP3 regulates OvCa cell function by modulating recruitment and polarization of tumor associated macrophages. Enhanced anti-tumor immunity was evidenced by increased IFN-β level in combination groups. Conclusion: Our study evaluated the effects of inflammasome modulation on anti-tumor efficacy of platinum agent and PARPi highlighting the interconnection between inflammatory mechanisms and carcinogenesis. Targeting NLRP3 inflammasome synergized and enhanced the anti-tumor activity of platinum agent and PARPi potentially by reshaping the tumor microenvironment (TME) and increasing the anti-tumor immunity and apoptosis. Overall, NLRP3 blockade can be a novel strategy for overcoming therapy resistance and for modulating TME in OvCa. Citation Format: Shaheen Mahira, Mackenzy Radolec, Philip Jones, Santiago Panesso, Siddharth Krishnan, Fernando Munguia, Sibel Yilmaz, Robert P. Edwards, Alexander B. Olawaiye, Haider Mahdi. NLRP3 inflammasome targeting to overcome platinum and PARPi resistance by modulating cancer related inflammation in ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 2172.