Vertical Pathway Inhibition Overcomes Adaptive Feedback Resistance to KRASG12C Inhibition

Abstract

◥Purpose: Although KRAS represents the most commonly mutated oncogene, it has long been considered an "undruggable" target. Novel covalent inhibitors selective for the KRAS G12C mutation offer the unprecedented opportunity to target KRAS directly. However, prior efforts to target the RAS-MAPK pathway have been hampered by adaptive feedback, which drives pathway reactivation and resistance.Experimental Design: A panel of KRAS G12C cell lines were treated with the KRAS G12C inhibitors ARS-1620 and AMG 510 to assess effects on signaling and viability. Isoform-specific pulldown of activated GTP-bound RAS was performed to evaluate effects on the activity of specific RAS isoforms over time following treatment. RTK inhibitors, SHP2 inhibitors, and MEK/ERK inhibitors were assessed in combination with KRAS G12C inhibitors in vitro and in vivo as potential strategies to overcome resistance and enhance efficacy. Results:We observed rapid adaptive RAS pathway feedback reactivation following KRAS G12C inhibition in the majority of KRAS G12C models, driven by RTK-mediated activation of wild-type RAS, which cannot be inhibited by G12C-specific inhibitors. Importantly, multiple RTKs can mediate feedback, with no single RTK appearing critical across all KRAS G12C models. However, coinhibition of SHP2, which mediates signaling from multiple RTKs to RAS, abrogated feedback reactivation more universally, and combined KRAS G12C /SHP2 inhibition drove sustained RAS pathway suppression and improved efficacy in vitro and in vivo.Conclusions: These data identify feedback reactivation of wildtype RAS as a key mechanism of adaptive resistance to KRAS G12C inhibitors and highlight the potential importance of vertical inhibition strategies to enhance the clinical efficacy of KRAS G12C inhibitors. Analysis and interpretation of data (e.g., statistical analysis, biostatistics, computational analysis):

SHP2 Inhibition Abrogates Adaptive Resistance to KRASG12C-Inhibition and Remodels the Tumor Microenvironment ofKRAS-Mutant Tumors

“…Furthermore, PTPN11 KO or SOS1 knockdown had biological and biochemical consequences similar to those of SHP099. Our results are consistent with, and strengthen, previous studies of the effects of SHP2 modulation on G12C-I inhibitor action (22,(38)(39)(40)(41). Fig S3 I-J) revealed that PTP activity is essential, whereas C-terminal tyrosine residues play a modulatory role, in adaptive resistance to G12C-Is.…”

“…Recent reports (and our unpublished observations; see Results) show that KRAS G12C -mutant cancer cell lines treated with G12C-Is also develop adaptive resistance (22,(38)(39)(40)(41). These studies reported that adaptive response to G12C-Is could be minimized by combining G12C-I with RTK or SHP2 inhibitors (22,38,40,41). Some of these findings were validated in human cell-derived (CDXs) or patient-derived xenografts (PDXs) (39).…”

“…Recently, several groups, including ours, provided strong evidence that SHP2 acts upstream of SOS1/2 to regulate exchange; consequently, SHP2-Is abrogate adaptive resistance to BRAF-or MEK-inhibitors (28,(34)(35)(36)(37). Recent reports (and our unpublished observations; see Results) show that KRAS G12C -mutant cancer cell lines treated with G12C-Is also develop adaptive resistance (22,(38)(39)(40)(41). These studies reported that adaptive response to G12C-Is could be minimized by combining G12C-I with RTK or SHP2 inhibitors (22,38,40,41).…”

“…al. (40) argued that adaptive resistance to G12C-Is involves upregulation of RTK signaling and activation of WT RAS, which cannot be targeted by the inhibitor, whereas Xue et al (41) reported that resistance arises from pre-existing heterogeneity that enables some tumor cells to survive by inducing mutant KRAS to levels that exceed inhibitor targeting capacity. Like Ryan et al, we observed induction of RTKs/RTK ligand genes following ARS treatment, and similar to our previous observations on MEK-I effects (35), we saw different patterns of RTK/RTK ligands induced by G12C-I in different cell lines, even within the same cancer histotype.…”

Prognostic Values, ceRNA Network, and Immune Regulation Function of SDPR in KRAS-mutant Lung Cancer

“…In the case of non-small cell lung cancer (NSCLC), KRAS mutations occur predominantly in codons 12 and 13, and most frequent variants including G12C, G12V, and G12D (9,17). Recently, a series of compounds targeted KRAS-G12C variant were developed and achieved promising effects on preclinical experiments and phase I clinical trials (18)(19)(20). However, the clinical bene ts especially for other KRAS variants remain clari ed.…”