Development of Gemcitabine-Modified miRNA Mimics as Cancer Therapeutics for Pancreatic Ductal Adenocarcinoma

Abstract

Pancreatic cancer, including its most common subtype, pancreatic adenocarcinoma (PDAC), has the lowest five-year survival rate among patients with pancreatic cancer in the United States. Despite advancements in anticancer treatment, the overall median survival for patients with PDAC has not dramatically improved. Therefore, there is an urgent need to develop new strategies of treatment to address this issue. Non-coding RNAs, including microRNAs (miRNAs), have been found to have major roles in carcinogenesis and the subsequent treatment of various cancer types like PDAC. In this study, we developed a treatment strategy by modifying tumor suppressor miRNAs, hsa-miRNA-15a (miR-15a) and hsa-miRNA-194-1 (miR-194), with the nucleoside analog chemotherapeutic gemcitabine (Gem) to create Gem-modified mimics of miR-15a (Gem-miR-15a) and miR-194 (Gem-miR-194). In a panel of PDAC cell lines, we found that Gem-miR-15a and Gem-miR-194 induce cell cycle arrest and apoptosis, and these mimics are potent inhibitors with IC50 values up to several hundred fold less than their native counterparts or Gem alone. Furthermore, we found that Gem-miR-15a and Gem-miR-194 retained miRNA function by downregulating the expression of several key targets including WEE1, CHK1, BMI1, and YAP1 for Gem-miR-15a, and FOXA1 for Gem-miR-194. We also found that our Gem-modified miRNA mimics exhibit an enhanced efficacy compared to Gem alone in patient-derived PDAC organoids. Furthermore, we observed that Gem-miR-15a significantly inhibits PDAC tumor growth in vivo without observing any noticeable signs of toxicity. Overall, our results demonstrate the therapeutic potential of Gem-modified miRNAs as a treatment strategy for PDAC. One Sentence SummaryYuen and Hwang et. al. have developed a potent therapeutic strategy for patients with pancreatic cancer by modifying microRNAs with gemcitabine.