协同破坏KRAS和FAK通路：一条用于优化PDAC治疗的临床前研发管线

Background: KRAS mutations are among the most prevalent oncogenic drivers across solid tumors, with particularly high incidence in Pancreatic Ductal Adenocarcinoma (PDAC). Despite their clinical relevance, direct targeting of KRAS has historically been difficult. The advent of KRAS G12C-specific inhibitors has marked a breakthrough in targeted therapy, yet acquired resistance remains a major challenge. RMC-6236 (daraxonrasib), a noncovalent RAS(ON) inhibitor, targets the active GTP-bound form of both mutant and wild-type RAS isoforms and has shown potent antitumor activity, especially in codon 12 KRAS-mutant cancers. In a Phase 1 trial for metastatic PDAC, RMC-6236 extended progression-free survival to approximately eight months. Recent studies suggest that KRAS inhibition may sustain focal adhesion kinase (FAK) activation, implicating the FAK-YAP axis and tumor-associated fibrosis in resistance. FAK, a key regulator of survival and DNA damage repair, has emerged as a promising co-target, with evidence of synergy between FAK inhibition and KRAS blockade, as well as enhanced sensitivity to PD-1 checkpoint inhibitors and radiation. We hypothesize that dual targeting of KRAS and FAK pathways will yield synergistic therapeutic effects in PDAC by disrupting oncogenic signaling and promoting cell death. To test this, we employ patient-derived organoid (PDO) cultures that preserve tumor architecture, heterogeneity, and stromal structure, enabling physiologically relevant evaluation of drug combinations. Methods: Patient-derived cells were treated with RMC-6236, defactinib, and ifebemtinib, alone and in combination, in 2D and 3D viability assays. Organoids were generated by co-culturing tumor cells and fibroblasts (1:1) for 72 hours, then treated with an 8-point, 2-fold serial dilution of drugs for another 72 hours. Synergy was assessed using Bliss analysis via Combenefit, and 2D dose responses were analyzed in GraphPad Prism using Student's t-test. Western blotting was performed to evaluate RAS-MAPK pathway inhibition and apoptosis markers. Results: Preliminary data from four KRAS-mutant PDOs (G12D, G12V, G12R) revealed robust synergy between RMC-6236 and either FAK inhibitor, with up to 10-fold and 100-fold increases in efficacy for defactinib or ifebemtinib and RMC-6236, respectively. Western blot analysis confirmed suppression of RAS-MAPK signaling, downregulation of c-MYC, and increased apoptotic markers including cleaved PARP and activated Caspase-3. These findings support the potential of KRAS-FAK co-targeting strategies in PDAC and lay the groundwork for future clinical development. These findings underscore a mechanistic interplay between KRAS and FAK signaling pathways, suggesting that dual targeting may overcome resistance and enhance cell death in KRAS-mutant PDAC, to improve outcomes in KRAS-driven pancreatic cancers.