Inhibiting KRAS with CD47 and immune checkpoint overcomes intrinsic resistance to combined KRAS and immune checkpoint inhibitor therapy

Abstract

Although Kirsten rat sarcoma virus (KRAS) G12C inhibitors alter the treatment strategy for patients with KRAS G12C-mutant lung cancer, their efficacy remains insufficient to eliminate tumors. Here, we identify that inhibition of mutant KRAS promotes escape from macrophage phagocytosis by upregulating the expression of cluster of differentiation 47 (CD47) and CD24. These proteins are induced by the binding of FOXA1 to the super-enhancer of CD47 and grainyhead-like transcription factor 2 (GRHL2) to the promoter of CD24, respectively. Whereas the addition of an anti-CD47 antibody restores macrophage phagocytosis, phagocytic macrophages induce programmed death-ligand 1 (PD-L1) expression, resulting in the suppression of CD8 T cell activation. Combination of a KRAS inhibitor with anti-CD47 and anti-PD-L1 antibodies achieves long-term survival in an orthotopic murine model recalcitrant to KRAS inhibition with immune checkpoint therapy. These results suggest that targeting KRAS with an anti-CD47 antibody and immune checkpoint blockade is a promising strategy, especially in immune-cold lung tumors.

Keywords: CD47; KRAS mutation; immune checkpoint inhibitor.