Abstract 6647: Targeting DCLK1-mediated glutamine addiction in chemoresistant ovarian cancer

Ovarian cancer (OC) presents significant therapeutic challenges due to its frequent late-stage diagnosis accompanied by distant metastases and the development of chemoresistance. As existing FDA-approved targeted therapies for OC do not adequately address peritoneal metastases, there is an urgent need for innovative treatment strategies that specifically target the molecular and cellular pathways underlying metastasis and disease recurrence. Doublecortin-like kinase 1 (DCLK1) is a serine/threonine kinase with a demonstrated role in cancer cell stemness, epithelial-mesenchymal transition (EMT), disease progression in gastrointestinal and pancreatic cancers and resistance in ovarian and lung cancer. The study objective is to evaluate the functional role of DCLK1 in the peritoneal metastasis of OC and investigate the associated benefits of antagonizing it as a novel strategy to mitigate OC metastasis. Our prior studies demonstrate DCLK1 inhibition reduces the number of visible metastases in an orthotopic OC model in mice. In this study, we used pharmacological inhibition (DCLK1-IN-1), and genetic manipulation (DCLK1 CRISPR-knockout (KO) and over-expression systems) to assess the role of DCLK1 in promoting OC metastasis. We observed that elevated DCLK1 expression enhanced OC cell adhesion to different extracellular matrices including collagen, fibronectin, and laminin. Furthermore, DCLK1 inhibition effectively reduced mesothelial cell clearance relative to control. Targeted gene expression profiling and pathway analysis revealed DCLK1 inhibition in cisplatin resistant (CPR) OC spheroids upregulated genes involved in glutamine metabolism. Using metabolic flux assays, we demonstrated increased oxygen consumption in DCLK1 KO CPR cells that was abrogated by BPTES (glutamine oxidation inhibitor). Furthermore, we show that combined treatment of OC CPR spheroids with DCLK1 inhibitor (DCLK1-IN-1) and glutamine antagonist (DRP-104) showed a synergistic cytotoxic effect. In addition, the novel combination strategy was significantly effective in reducing OC cell adhesion and mesothelial cell clearance relative to single agent alone. Collectively, our findings establish DCLK1 as a key regulator of metastasis and demonstrate that its inhibition induces glutamine dependency in chemoresistant tumor cells. Thus, the combined use of DCLK1 inhibitors (e.g., DCLK1-IN-1) with glutamine metabolism inhibitors (e.g., DRP-104) represents a rational therapeutic approach to mitigate peritoneal metastases in a chemoresistant setting. Citation Format: Samrita Dogra, Cole Hladik, Sugantha Priya Elayapillai, Bethany Hannafon. Targeting DCLK1-mediated glutamine addiction in chemoresistant 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 6647.