mTORC2 controls cancer cell survival by modulating gluconeogenesis

Area of Science:

• Cancer Biology
• Cellular Metabolism
• Molecular Oncology

Background:

• Cancer cells reprogram metabolism for rapid growth, but molecular mechanisms remain unclear.
• Mechanistic target of rapamycin (mTOR) is a key regulator of cell growth, proliferation, and survival.
• Understanding metabolic rewiring is crucial for developing effective cancer therapies.

Purpose of the Study:

• To investigate the role of mTOR in metabolic reprogramming of cancer cells.
• To elucidate the molecular mechanisms linking mTOR inhibition to metabolic pathway alterations.
• To identify potential therapeutic targets for hepatocellular carcinoma (HCC) and renal cell carcinoma (RCC).

Main Methods:

• Inhibition of mTOR using pharmacologic agents and RNA interference in HCC and RCC cell lines.
• Analysis of metabolic flux, gene expression (PCK1, G6PC), enzyme activity, and lipogenesis.
• Validation using human HCC and RCC transcriptome data and correlation analysis.

Main Results:

• mTOR inhibition caused a metabolic shift from glycolysis to gluconeogenesis, reducing proliferation and survival.
• Gluconeogenesis augmentation was linked to increased PCK1 and G6PC expression and lactate dehydrogenase activity.
• Concomitant knockdown of PCK1, but not G6PC, with mTOR inhibition reversed the pro-survival effects.
• Distinct downregulation of PCK1 and G6PC was observed in human HCC and RCC transcriptome data.

Conclusions:

• mTOR inhibition can promote cancer cell survival through gluconeogenesis, particularly in HCC and RCC.
• PCK1 is a critical mediator of this mTOR-dependent pro-survival metabolic rewiring.
• Targeting the interplay between mTOR and gluconeogenesis, specifically PCK1, offers a novel therapeutic strategy for cancer treatment.