Loss of TSC1/TSC2 sensitizes immune checkpoint blockade in non–small cell lung cancer

Abstract

Tuberous sclerosis complex subunit 1 ( TSC1 ) and 2 ( TSC2 ) are frequently mutated in non–small cell lung cancer (NSCLC), however, their effects on antitumor immunity remained unexplored. A CRISPR screening in murine Kras G12D / Trp53 −/− (KP) model identified Tsc1 and Tsc2 as potent regulators of programmed cell death ligand 1 (Pd-l1) expression in vitro and sensitivity to anti–programmed cell death receptor 1 (PD-1) treatment in vivo. TSC1 or TSC2 knockout (KO) promoted the transcriptional and membrane expression of PD-L1 in cell lines. TSC2 -deficient tumors manifested an inflamed microenvironment in patient samples and The Cancer Genome Atlas dataset. In syngeneic murine models, KP- Tsc2 -KO tumors showed notable response to anti–PD-1 antibody treatment, but Tsc2 –wild-type tumors did not. Patients with TSC1 / TSC2 -mutant NSCLC receiving immune checkpoint blockade (ICB) had increased durable clinical benefit and survival. Collectively, TSC1 / TSC2 loss defines a distinct subtype of NSCLC characterized as inflamed tumor microenvironment and superior sensitivity to ICB.