Abstract 467: Genetic ablation of microRNA-10b improves treatment outcomes in mouse models of pancreatic cancer

Abstract Pancreatic ductal adenocarcinoma (PDAC) is a recalcitrant and lethal disease with an overall 5-year survival rate of less than 12%. PDAC is a heterogeneous disease characterized by highly aggressive cancer cells, extensive desmoplastic reaction, and hypovascularity. These unique features endow PDAC tumors with an array of innate resistance mechanisms against standard-of-care (SOC) chemotherapy: gemcitabine/nab-paclitaxel or FOLFIRINOX. Thus, there is clinical need to develop novel targets that enhance treatment efficacy of SOC chemotherapy. microRNA-10b (miR-10b) expression is frequently upregulated in PDAC and correlates with poor outcome. High levels of miR-10b expression within cancer cells correlates with poor treatment response to gemcitabine-containing neoadjuvant chemotherapy and poor overall clinical outcome. We and others reported that miR-10b exerts cancer cell-intrinsic pro-survival, anti-apoptotic, and pro-metastatic functions via downregulation of key target genes (i. e. , BIM, PTEN, TIAM1). We hypothesize that upregulation of miR-10b expression is a chemoresistance mechanism to increase cell survival and inhibit apoptosis in PDAC. To test this hypothesis, we generated a KPC model (KrasG12D-driven, p53-deleted by Pdx1-Cre) with global Mir-10b gene knockout (Mir-10bKO). Animals were recruited when their tumor volume reached 200 mm3 by multi-mouse MR imaging and were randomly assigned to control or treatment groups (100 mg/kg of gemcitabine q4d). Tumor growth was monitored by weekly MR imaging sessions throughout the duration of the treatment. Untreated KPC;Mir-10bKO animals survived several weeks longer than untreated KPC animals (21. 7 vs. 18 weeks, p = 0. 056), suggesting a weak but detectable tumor promoting role of miR-10b. Remarkably, loss of miR-10b activity enhances treatment response to gemcitabine and significantly prolongs survival in this KPC model. Treated KPC animals lived only 5 weeks longer than untreated KPC (23 vs 18 weeks, p = 0. 015), whereas KPC;Mir-10bKO lived 9 weeks longer (27 vs 18 weeks, p = 0. 002). Notably, we observed a more durable response in treated female KPC;Mir-10bKO animals (n = 4) compared to any other experimental group (n 5). We are currently performing tissue and molecular analyses to identify direct target genes involved in chemoresistance and sex-specific modulation of treatment response. Citation Format: Katarzyna Kempinska, Sudhakar Samuel, Saiprashanth Rajesh, Christiane Mallett, Lorenzo Sempere. Genetic ablation of microRNA-10b improves treatment outcomes in mouse models of pancreatic cancer abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (6Suppl): Abstract nr 467.