Cell Type–specific Adaptive Signaling Responses to KRASG12C Inhibition

Abstract

Purpose: Covalent inhibitors of KRASG12C specifically target tumors driven by this form of mutant KRAS, yet early studies show that bypass signaling drives adaptive resistance. Although several combination strategies have been shown to improve efficacy of KRASG12C inhibitors (KRASi), underlying mechanisms and predictive strategies for patient enrichment are less clear. Experimental Design: We performed mass spectrometry–based phosphoproteomics analysis in KRASG12C cell lines after short-term treatment with ARS-1620. To understand signaling diversity and cell type–specific markers, we compared proteome and phosphoproteomes of KRASG12C cells. Gene expression patterns of KRASG12C cell lines and lung tumor tissues were examined. Results: Our analysis suggests cell type–specific perturbation to ERBB2/3 signaling compensates for repressed ERK and AKT signaling following ARS-1620 treatment in epithelial cell type, and this subtype was also more responsive to coinhibition of SHP2 and SOS1. Conversely, both high basal and feedback activation of FGFR or AXL signaling were identified in mesenchymal cells. Inhibition of FGFR signaling suppressed feedback activation of ERK and mTOR, while AXL inhibition suppressed PI3K pathway. In both cell lines and human lung cancer tissues with KRASG12C, we observed high basal ERBB2/3 associated with epithelial gene signatures, while higher basal FGFR1 and AXL were observed in cells/tumors with mesenchymal gene signatures. Conclusions: Our phosphoproteomic study identified cell type–adaptive responses to KRASi. Markers and targets associated with ERBB2/3 signaling in epithelial subtype and with FGFR1/AXL signaling in mesenchymal subtype should be considered in patient enrichment schemes with KRASi.

The KRAS-G12C inhibitor: activity and resistance

“…However, another study suggests that wild-type RAS activation mediated by multiple RTKs, rather than a single RTK, is responsible for the acquired resistance of KRAS-G12C inhibitors (ARS-1620 and sotorasib) in various types of cancer cell lines [32]. Regardless, many independent studies demonstrate the importance of PTPN11/SHP2 as a common downstream of RTKs to activate the wild-type or mutant KRAS protein in mediating acquired drug resistance [10,[32][33][34][35][36][37]. Clinical trials (NCT04330664) are ongoing to test the combination with TNO155 (SHP2 inhibitor) and adagrasib in patients with advanced solid tumors carrying KRAS-G12C mutation.…”

“…In addition, the activation of the PI3K-AKT-mTOR pathway contributes to the development of sotorasib resistance in human PDAC cell line in vitro and in xenograft mouse models [38]. Gene set enrichment analysis and mass spectrometry-based phosphoproteomics analysis found that induction of epithelial-to-mesenchymal transition (EMT) promotes resistance to sotorasib or ARS-1620 through activation of PI3K or ERK pathway in NSCLC cells in a cell type-dependent manner [35,39]. Nuclear factor, erythroid 2 like 2 (NFE2L2, best known as NRF2) regulated by kelch like ECH associated protein 1 (KEAP1) is a key transcription factor in cellular antioxidant response.…”

Escaping KRAS: Gaining Autonomy and Resistance to KRAS Inhibition in KRAS Mutant Cancers

“…Several mechanisms for the reactivation of MAPK signaling, as well as for mutant KRAS-independent activation of PI3K signaling, have been reported [42,60,[62][63][64]. As presented earlier, the inhibition of the MAPK pathway induces feedback reactivation of MAPK signaling via multiple activated RTKs in various types of cancer cell lines.…”

“…To date, multiple preclinical studies have reported various mechanisms of resistance to KRAS G12C inhibitors. These studies overall suggest the reactivation of MAPK signaling and/or mutant KRAS-independent activation of the PI3K pathway as common modalities to bypass KRAS G12C blockade, ultimately resulting in KRAS G12C inhibitor resistance [42,[62][63][64].…”

“…EMT is also associated with intrinsic and acquired resistance to KRAS G12C inhibitors in NSCLC [42,62]. Gene set enrichment analysis (GSEA) between KRAS G12C inhibitorsensitive and intrinsically resistant cells identified a KRAS dependency signature that was significantly associated with sensitivity to AMG510 [42].…”