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

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 KRAS^G12C mouse cancer cell lines treated with 100 nmol/L MRTX849 for 24 hours or 48 hours. D, COX2 mRNA expression in 3LL ΔNRAS and KPAR^G12C 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 KPAR^G12C orthotopic tumors treated as shown in D. F, Immunoblot for COX2 in human KRAS^G12C lung cancer cell lines treated with MRTX849 for 24 hours. A549 (KRAS^G12S) 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 KPAR^G12C cells treated for 2, 3, or 5 days with 100 nmol/L MRTX849. J, COX2 mRNA expression in MRTX849 on-treatment and relapsed KPAR^G12C 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.