p53 Drives Lung Cancer Regression through a TSC2/TFEB-dependent Senescence Program.

Pharmacologic restoration of p53 tumor suppressor function is a conceptually appealing therapeutic strategy for the many deadly cancers with compromised p53 activity, including lung adenocarcinoma. However, the p53 pathway has remained undruggable, partly because of insufficient understanding of how to drive effective therapeutic responses without toxicity. In this study, we use mouse and human models to deconstruct the transcriptional programs and sequelae underlying robust therapeutic responses in lung adenocarcinoma. We show that p53 drives potent tumor regression by direct Tsc2 transactivation, leading to mTORC1 inhibition and Transcription factor EB (TFEB) nuclear accumulation, which in turn triggers lysosomal gene expression programs, autophagy, and cellular senescence. Senescent lung adenocarcinoma cells secrete factors to recruit macrophages, precipitating cancer cell phagocytosis and tumor regression. Collectively, our analyses reveal a surprisingly complex cascade of events underlying a p53 therapeutic response in lung adenocarcinoma and illuminate targetable nodes for p53 combination therapies, thus establishing a critical framework for optimizing p53-based therapeutics. SIGNIFICANCE: Cancer therapies based on targeting the p53 pathway remain elusive. To address this gap, we unravel the detailed sequence of events governing p53-induced tumor regression in lung adenocarcinoma. These analyses reveal a TSC2-mTORC1-TFEB axis underlying p53-driven senescence and tumor regression, which suggests new strategies to perfect p53-based combination therapies for lung adenocarcinoma.