Abstract
METHODS
We performed a genome-wide CRISPR-KO screening, followed by four follow-up focused screenings, leading to the identification of resistance mediators, which were further validated through functional genetic and pharmacological experiments, both in vitro and in vivo.
CONCLUSIONS
Alterations in the PI3K/AKT/mTOR and JUN pathways can induce resistance to multiple combinations of MAPK pathway inhibitors, and may serve as biomarkers for sensitivity/resistance in clinical trials exploring such combinations in KRAS-mutant PDAC.
RESULTS
Through unbiased CRISPR-based screenings, we identified mTOR and JUN hyperactivation as interconnected mechanisms that overcome MAPK suppression. Further investigation pointed at JUN as the most downstream resistance mediator, and indirect therapeutic target, using MAP2K4 inhibitors.
BACKGROUND
Pancreatic ductal adenocarcinoma (PDAC) is often driven by KRAS mutations, but inhibitors targeting the most frequent KRAS substitutions in PDAC are not yet approved in the clinic. We previously discovered that KRAS-mutant PDAC is sensitive to the combination of SHP2 and ERK inhibitors, recently investigated in the Phase I/Ib clinical trial NCT04916236. Lately, RAS(ON) multi-selective inhibitors have entered clinical development, representing a promise for mono or combination therapies in PDAC. However, resistance may arise even for combination therapies. Here, we aimed at anticipating mechanisms of resistance to SHP2 plus ERK or RAS(ON) multi-selective inhibitors.