Fra-2 controls the response to the KRAS inhibitor MRTX-1133 in pancreatic ductal adenocarcinoma.

selective inhibitor MRTX-1133. Using a combination of established PDAC cell lines, xenograft models, and patient-derived organoids, we demonstrate that Fra-2 expression is consistently upregulated following MRTX-1133 treatment. Functional assays reveal that Fra-2 overexpression promotes resistance by reprogramming the transcriptional landscape, directly enhancing mTOR expression and signaling. Consistently, FRA2 and MTOR levels strongly correlate in PDAC patient samples. Collectively, these findings uncover a mechanistic interplay between Fra-2 and the mTOR pathway in MRTX-1133-resistant PDAC, highlighting that targeting Fra-2 may represent a valuable approach to enhance the efficacy of KRASi.