cAMP response element-binding protein mediates immune-evasion of KRAS-mutant lung adenocarcinoma

Abstract

Introduction: cAMP response element-binding protein (CREB) mediates proliferative and inflammatory transcription in neurodegeneration and cancer, but its role in malignant immune-evasion is obscure. Objectives: To discover the mechanisms underlying the oncogenic properties of CREB in KRAS-mutant lung adenocarcinoma (LUAD). Materials and Methods: We used conditional deletion, focal overexpression, and pharmacologic inhibition of CREB in different mouse and cellular models of early-stage and metastatic KRAS-mutant LUAD. We determined the neutrophil (ΝΦ) influx in the bronchoalveolar lavage (BAL) from LUAD-affected conditionally Creb1-deleted lungs. We employed The Cancer Genome Atlas, the GEO dataset GSE43458, and the human protein atlas to examine CREB and CXCR1 in human LUAD. Results: CREB is overexpressed in murine KRAS-mutant LUAD, pulmonary deletion of Creb1 (encoding murine CREB) inhibits LUAD development, and Creb1-overexpression augments the tumorigenicity of KRAS-mutant cells. Conditional Creb1 deletion in KRAS -mutant LUAD cells causes overexpression of CXCR1 ligands, and LUAD-bearing Creb1-deleted mice display increased pulmonary ΝΦ. Cxcr1-deficient mice are selectively permissive to KRAS-mutant tumor growth and show defective ΝΦ recruitment. The pro-tumor effects of CREB require intact host Cxcr1 and those of host Cxcr1 necessitate mutant KRAS in cancer cells. Pharmacologic CREB blockade prevents tumor growth and restores ΝΦ recruitment only when initiated before immune-evasion of KRAS-mutant LUAD. CREB and CXCR1 expression of human LUAD are compartmentalized to tumor and stromal cells, respectively, while CREB-controlled genes profoundly impact survival. Conclusions: CREB-mediated immune evasion of KRAS-mutant LUAD rests on signaling to ΝΦ CXCR1 and is actionable.