Project description:Expression analysis in baseline tissue samples from KRAS G12C mutant patients, follow-up of KRAS mutant patients treated with KRAS G12C inhibitors in blood and analysis of paired biopsies
Project description:Cysteine chemoproteomics data for paper "Rapid Target Engagement of KRAS G12C Tricomplex Inhibitor RO3903 Overcomes Resistance and Drives Durable Tumor Regression"
Project description:The discovery of KRAS G12C inactive state inhibitors represents a significant advancement in the field of precision oncology. While inactive state inhibition shows promise in patients, SWII-binding inhibitors targeting both inactive and active states remain an underdeveloped therapeutic modality. Here, we describe the discovery of KRAS G12C dual inhibitors that bind the SWII allosteric site using a chemically differentiated warhead to covalently modify both KRAS G12C inactive and active states. Co-crystal structures reveal that these inhibitors perturb a key water-mediated hydrogen bonding network and trigger allosteric remodeling of the GTP-bound protein surface and Switch I to prevent binding to downstream effectors. Consistent with simultaneous targeting of the active and inactive state, dual inhibitors provide rapid covalent target engagement and suppression of MAPK signaling. However, KRAS G12C dual and inactive state inhibitors demonstrate similar efficacy in cellular and in vivo models despite faster target inhibition afforded by targeting the active state. Furthermore, KRAS G12C dual and inactive state inhibitors show similar cellular efficacy in the presence of growth factors that drive KRAS, wt NRAS and wt HRAS to the active state. These data provide the first detailed account of targeting the active and inactive state of KRAS and highlight the absence of a mechanistic advantage in the context of prolonged KRAS G12C inhibition and efficacy.
Project description:KRAS is the most frequently mutated oncogene in human cancer, and KRAS inhibition has been a longtime goal. Recently, inhibitors (G12C-Is) that bind KRAS-G12C-GDP and react with Cys-12 were developed. Using new affinity reagents to monitor KRAS-G12C activation and inhibitor engagement, we found that SHP2 inhibitors (SHP2-Is) increased KRAS-GDP occupancy, enhancing G12C-I efficacy. SHP2-Is abrogated feedback signaling by multiple RTKs and adaptive resistance to G12C-Is in vitro, in xenografts, and in syngeneic KRAS-G12C-mutant pancreatic ductal adenocarcinoma (PDAC) and non-small cell lung cancer (NSCLC) models. The combination of SHP2-I and G12C-I evoked favorable changes in the immune microenvironment, decreasing myeloid suppressor cells, increasing CD8+ T cells, and sensitizing tumors to PD-1 blockade. Experiments using an inhibitor-resistant SHP2 mutant showed that SHP2 inhibition in PDAC cells is required for tumor regression and remodeling of the immune microenvironment, but SHP2-Is also had direct effects on angiogenesis. Our results demonstrate that SHP2-I/G12C-I combinations confer a substantial survival benefit in PDAC and NSCLC and identify additional potential combination strategies. G12C-Is show significant, but limited, efficacy as single agents, in part because of “adaptive resistance”. We find that combining G12C-Is with SHP2-Is abrogates adaptive resistance and results in favorable changes in the immune microenvironment that potentiate PD-1 blockade in KRAS-mutant malignancies. SHP2-Is also can have direct, context-dependent, effects on tumor vasculature.
Project description:Although KRAS G12C inhibitors have altered the treatment strategy of patients with KRAS G12C mutant lung cancer, their efficacy is insufficient to eliminate tumors. Here, we identified that inhibition of mutant KRAS promotes escape from macrophage phagocytosis by upregulating the expression of ‘don’t eat me’ signal proteins, including CD47. CD47 was induced by the binding of FOXA1 to the super-enhancer of CD47. The addition of an anti-CD47 antibody restored macrophage phagocytosis and phenotype of macrophages.
Project description:Treatment of NSCLC KRAS G12C mutant tumors with targeted KRAS inhibitors, such as sotorasib and adagrasib, is invariably associated with the emergence of acquired resistance. The mechanisms responsible for resistance to these agents have largely remained unclear. We report that patients with NSCLC KRAS G12C tumors expressing increased levels of the MUC1 gene exhibit decreases in overall survival in response to sotorasib and adagrasib. In investigating the basis for this finding, we found that exposure of NSCLC KRAS G12C mutant cells to these agents induces expression of the oncogenic MUC1-C/M1C protein. We show that M1C induction is STAT1 dependent and that targeting M1C increases sensitivity to sotorasib. Studies of sotorasib-resistant cells further reveal upregulation of M1C chromatin levels in association with activation of the epithelial-mesenchymal transition (EMT). Mechanistically, M1C drives NF-kB p65-mediated induction of the ZEB1 EMT-TF. Furthermore, targeting M1C NF-kB ZEB1 signaling suppresses EMT and sotorasib resistance. Having identified this M1C dependence, we demonstrate that targeting M1C with an antibody-drug conjugate (ADC) is effective against sotorasib-resistant cells growing in vitro and as tumor xenografts. These findings identify M1C as a major effector of sotorasib resistance and as a target for ADC treatment of patients with refractory NSCLC KRAS G12C mutant tumors.