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

Area of Science:

• Oncology
• Molecular Biology
• Cancer Research

Background:

• Pharmacological restoration of p53 tumor suppressor function is a promising strategy for cancers like lung adenocarcinoma (LUAD).
• The p53 pathway's complexity and potential toxicity have hindered its therapeutic application.
• Understanding the precise mechanisms of p53-mediated responses is crucial for developing effective treatments.

Purpose of the Study:

• To deconstruct the transcriptional programs and downstream effects of p53 in LUAD.
• To identify key molecular events driving therapeutic responses and tumor regression.
• To illuminate potential targets for optimizing p53-based combination therapies.

Main Methods:

• Utilized both mouse and human models of LUAD.
• Analyzed transcriptional programs and cellular sequelae following p53 activation.
• Investigated the roles of Tsc2, mTORC1, TFEB, autophagy, senescence, and macrophage recruitment.

Main Results:

• p53 directly transactivates Tsc2, inhibiting mTORC1 and promoting TFEB nuclear accumulation.
• This cascade induces lysosomal gene expression, autophagy, and cellular senescence in LUAD cells.
• Senescent cells recruit macrophages, leading to phagocytosis and tumor regression.

Conclusions:

• A complex cascade of events underlies p53 therapeutic responses in LUAD.
• Targetable nodes within this cascade offer opportunities for combination therapies.
• This framework is critical for optimizing p53-based therapeutics in LUAD.