Figure 6 from CRISPR–Cas9 Screening Identifies KRAS-Induced COX2 as a Driver of Immunotherapy Resistance in Lung Cancer

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posted on 2024-07-15, 07:20 authored by Jesse Boumelha, Andrea de Castro, Nourdine Bah, Hongui Cha, Sophie de Carné Trécesson, Sareena Rana, Mona Tomaschko, Panayiotis Anastasiou, Edurne Mugarza, Christopher Moore, Robert Goldstone, Phil East, Kevin Litchfield, Se-Hoon Lee, Miriam Molina-Arcas, Julian Downward

Oncogenic KRAS drives immunosuppressive COX2 expression in lung adenocarcinoma. A, Immunoblot for COX2 (left) and ELISA analysis for PGE2 concentration (right) in KPAR cells treated with 10 nmol/L trametinib (MEKi) for 24 hours or 48 hours. B and C, Immunoblot for COX2 (B) and ELISA analysis for PGE2 concentration (C) in KRASG12C mouse cancer cell lines treated with 100 nmol/L MRTX849 for 24 hours or 48 hours. D, COX2 mRNA expression in 3LL ΔNRAS and KPARG12C orthotopic tumors treated for 7 days with 50 mg/kg MRTX849. E, COX2-associated inflammatory signature (COX-IS) assessed by qPCR in 3LL ΔNRAS and KPARG12C orthotopic tumors treated as shown in D. F, Immunoblot for COX2 in human KRASG12C lung cancer cell lines treated with MRTX849 for 24 hours. A549 (KRASG12S) cells were used as the negative control. G, COX2 expression in RAS-low and RAS-high human lung cancer cell lines from the CCLE database. RPKM, reads per kilobase per million mapped reads. H, COX-IS in lung adenocarcinoma samples from TCGA stratified by RAS activity into five different groups, which are associated with specific co-occurring mutations (RAG0, KRAS wild-type; RAG1, KRAS/LKB1; RAG2, KRAS; RAG3, KRAS/TP53; RAG4, KRAS/CDKN2A). I, Immunoblot for COX2 in KPARG12C cells treated for 2, 3, or 5 days with 100 nmol/L MRTX849. J, COX2 mRNA expression in MRTX849 on-treatment and relapsed KPARG12C tumors. K, Kaplan–Meier survival of mice treated with daily oral gavage of 50 mg/kg MRTX849 alone or in combination with 30 mg/kg celecoxib, n = 8–20 per group. Analysis of survival curves was carried out using the log-rank (Mantel–Cox) test. Data are represented as mean ± SEM for A, C–E, and J, n = 8–9 per group. Groups were compared using unpaired, two-tailed Student t test (A, C–E, and G) or one-way ANOVA, FDR 0.05 (H and J). *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001.

Funding

HORIZON EUROPE European Research Council (ERC)

Cancer Research UK (CRUK)

Medical Research Foundation

Wellcome Trust (WT)

'la Caixa' Foundation ('la Caixa')

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DOI - Is supplement to CRISPR–Cas9 Screening Identifies KRAS-Induced COX2 as a Driver of Immunotherapy Resistance in Lung Cancer

ARTICLE ABSTRACT

Oncogenic KRAS impairs antitumor immune responses. As effective strategies to combine KRAS inhibitors and immunotherapies have so far proven elusive, a better understanding of the mechanisms by which oncogenic KRAS drives immune evasion is needed to identify approaches that could sensitize KRAS-mutant lung cancer to immunotherapy. In vivo CRISPR–Cas9 screening in an immunogenic murine lung cancer model identified mechanisms by which oncogenic KRAS promotes immune evasion, most notably via upregulation of immunosuppressive COX2 in cancer cells. Oncogenic KRAS potently induced COX2 in both mouse and human lung cancer, which was suppressed using KRAS inhibitors. COX2 acted via prostaglandin E2 (PGE2) to promote resistance to immune checkpoint blockade (ICB) in lung adenocarcinoma. Targeting COX2/PGE2 remodeled the tumor microenvironment by inducing proinflammatory polarization of myeloid cells and influx of activated cytotoxic CD8+ T cells, which increased the efficacy of ICB. Restoration of COX2 expression contributed to tumor relapse after prolonged KRAS inhibition. These results provide the rationale for testing COX2/PGE2 pathway inhibitors in combination with KRASG12C inhibition or ICB in patients with KRAS-mutant lung cancer.Significance: COX2 signaling via prostaglandin E2 is a major mediator of immune evasion driven by oncogenic KRAS that promotes immunotherapy and KRAS-targeted therapy resistance, suggesting effective combination treatments for KRAS-mutant lung cancer.