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:BACKGROUNDThe KRAS proto-oncogene is among the most frequently mutated genes in cancer, yet for 40 years it remained an elusive therapeutic target. Recently, allosteric inhibitors that covalently bind to KRAS G12C mutations have been approved for use in lung adenocarcinomas. Although responses are observed, they are often short-lived, thus making in-depth characterization of the mechanisms of resistance of paramount importance.METHODSHere, we present a rapid-autopsy case of a patient who had a KRASG12C-mutant lung adenocarcinoma who initially responded to a KRAS G12C inhibitor but then rapidly developed resistance. Using deep-RNA and whole-exome sequencing comparing pretreatment, posttreatment, and matched normal tissues, we uncover numerous mechanisms of resistance to direct KRAS inhibition.RESULTSIn addition to decreased KRAS G12C-mutant allele frequency in refractory tumors, we also found reactivation of the MAPK pathway despite no new mutations in KRAS or its downstream mediators. Tumor cell-intrinsic and non-cell autonomous mechanisms included increased complement activation, coagulation, and tumor angiogenesis, and several lines of evidence of immunologic evasion.CONCLUSIONTogether, our findings reveal numerous mechanisms of resistance to current KRAS G12C inhibitors through enrichment of clonal populations, KRAS-independent downstream signaling, and diverse remodeling of the tumor microenvironment.FUNDINGRichard and Fran Duley, Jimmy and Kay Mann, the NIH, and the North Carolina Biotechnology Center.
Project description:KRAS G12C inhibitors (G12Ci) alone and in various combinations are being tested in multiple tumors with over-activation of the RAS/ERK pathway. KRAS plays a critical role in normal cell signaling; hence, G12Cis has been reported to create resistance. We found several novel pathways, including Hippo pathways, are enriched from significant dropouts upon MRTX849 treatment. Our results argue for testing KRAS G12C and TEAD inhibitor combinations in NSCLC patients.
Project description:We report RNAseq gene expression data following ARS-1620 treatment and shKRAS expressing cells (NCI-H358). We also compare gene expression changes following treatment with ARS-1620 or trametinib in NCI-H358, LU65 (KRAS-G12C+), and A549 (KRAS-G12S+) cells. Additionally we report a time course (4, 24, 48hr) of ARS-1620 and trametinib treated NCI-H358 cells.
Project description:KRAS G12C inhibitors (G12Ci) alone and in various combinations are being tested in multiple tumors with over-activation of the RAS/ERK pathway. KRAS plays a critical role in normal cell signaling; hence, G12Cis could influence the signaling pathways. We found that several novel pathways including Hippo pathways are upregulated upon MRTX849 treatment. Our results argue for testing KRAS G12C and TEAD inhibitor combinations in NSCLC patients.
Project description:Mutant KRAS (mut-KRAS) is present in 30% of all human cancers and plays a critical role in cancer cell growth and resistance to therapy. There is evidence from colon cancer that mut-KRAS is a poor prognostic factor and negative predictor of patient response to molecularly targeted therapy. However, evidence for such a relationship in non small cell lung cancer (NSCLC) is conflicting. KRAS mutations are primarily found at codons 12 and 13, where different base changes lead to alternate amino acid substitutions that lock the protein in an active state. The patterns of mut-KRas amino acid substitutions in colon cancer and NSCLC are quite different, with aspartate (D) predominating in colon cancer (50%) and cysteine (C) in NSCLC (47%). Through an analysis of a recently completed biopsy biomarker-driven, molecularly targeted multi-arm trial of 215 evaluable patients with refractory NSCLC we show that mut-KRas-G12C/V but not total mut-KRAS predicts progression free survival for the overall group, and for the sorafenib and vandetanib treatment arms. Transcriptome microarray data shows differential expression of cell cycle genes between mut-KRas-G12C/V and G12D patient tumors. A panel of NSCLC cell lines with known mut-KRas amino acid substitutions was used to identify pathways activated by the different mut-KRas, showing that mut-KRas-G12D activates both PI-3-K and MEK signaling, while mut-KRas G12C does not, and alternatively activates RAL signaling. This finding was confirmed using immortalized human bronchial epithelial cells stably transfected with wt-KRAS and different forms of mut-KRAS. Molecular modeling studies show that the different conformation imposed by mut-KRas-G12C could lead to altered association with downstream signaling transducers compared to wild type and mut-KRas-G12D. The significance of the findings for developing mut-KRAS therapies is profound, since it suggests that not all mut-KRas amino acid substitutions signal to effectors in a similar way, and may require different therapeutic interventions. Gene expression profiles were measured in 22 core biopsies from patients with refractory non-small cell lung cancer included in the Biomarker-integrated Approaches of Targeted Therapy for Lung Cancer Elimination (BATTLE). All tumors were KRAS mutants, but with different patterns of amino acid substitutions. Supervised analysis of transcriptome profiling was performed to compare cysteine or valine KRAS mutants with other KRAS mutants.
Project description:KRAS G12C inhibitors (G12Ci) alone and in various combinations are being tested in multiple tumors with over-activation of the RAS/ERK pathway. KRAS plays a critical role in normal cell signaling; hence, G12Cis could influence the signaling pathways. We found that several novel pathways including Hippo pathways are upregulated upon MRTX849 treatment. Our results argue for testing KRAS G12C and TEAD inhibitor combinations in NSCLC patients.
Project description:To characterize sotorasib resistance in lung adenocarcinomas (LUAD), we generated genetically engineered mice (Kras-G12C, Trp53-KO) and compared the transcriptional profiles of untreated and sotorasib-resistant tumors