Fedratinib induces non-classical G2/M arrest via mitotic-kinase inhibition and synergizes with mitomycin C to suppress pancreatic ductal adenocarcinoma.

Abstract

Pancreatic ductal adenocarcinoma (PDAC) is the most aggressive form of pancreatic cancer, with a 5-year survival rate below 10%, largely due to late diagnosis, high metastatic capacity, and resistance to standard therapies. Drug repurposing guided by polypharmacology offers a time- and cost-effective strategy to identify new treatments with reduced clinical risk. Fedratinib, a JAK2 inhibitor approved for myelofibrosis, was previously identified through our bioinformatics analysis as a compound capable of reversing KRAS-driven transcriptional programs in PDAC cells. This study investigates the therapeutic potential and underlying mechanisms of fedratinib in PDAC. Two KRAS-mutant PDAC cell lines were used for in vitro analyses. Cell viability, protein expression, and cell-cycle distribution or apoptosis were assessed using MTT assays, Western blot analysis, and flow cytometry, respectively. Cellular thermal shift assays (CETSA) were performed to evaluate drug-target engagement. In vivo efficacy was examined using a PANC-1 xenograft mouse model treated with fedratinib alone or in combination with mitomycin C. Fedratinib significantly reduced PDAC cell viability, which was associated with caspase-independent cell death, and induced a non-canonical G2/M phenotype characterized by G2/M accumulation, reduced expression of mitotic markers, and accelerated mitotic exit after release from prometaphase arrest. Kinome profiling revealed off-target inhibition of multiple mitotic kinases, which was confirmed by CETSA. Combination screening identified strong synergy between fedratinib and mitomycin C, which was validated in vitro and in vivo. Overall, these findings highlight fedratinib as a promising repurposed therapeutic agent for PDAC and support its combination with mitomycin C as a potential new treatment strategy.