Long non-coding RNA SNHG6 couples cholesterol sensing with mTORC1 activation in hepatocellular carcinoma

Nat Metab. 2022 Aug;4(8):1022-1040. doi: 10.1038/s42255-022-00616-7. Epub 2022 Aug 22.

Abstract

Cholesterol contributes to the structural basis of biological membranes and functions as a signaling molecule, whose dysregulation has been associated with various human diseases. Here, we report that the long non-coding RNA (lncRNA) SNHG6 increases progression from non-alcoholic fatty liver disease (NAFLD) to hepatocellular carcinoma (HCC) by modulating cholesterol-induced mTORC1 activation. Mechanistically, cholesterol binds ER-anchored FAF2 protein to promote the formation of a SNHG6-FAF2-mTOR complex. As a putative cholesterol effector, SNHG6 enhances cholesterol-dependent mTORC1 lysosomal recruitment and activation via enhancing FAF2-mTOR interaction at ER-lysosome contacts, thereby coordinating mTORC1 kinase cascade activation with cellular cholesterol biosynthesis in a self-amplified cycle to accelerate cholesterol-driven NAFLD-HCC development. Notably, loss of SNHG6 inhibits mTORC1 signaling and impairs growth of patient-derived xenograft liver cancer tumors, identifyifng SNHG6 as a potential target for liver cancer treatment. Together, our findings illustrate the crucial role of organelle-associated lncRNA in organelle communication, nutrient sensing, and kinase cascades.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carcinoma, Hepatocellular* / genetics
  • Carcinoma, Hepatocellular* / metabolism
  • Carcinoma, Hepatocellular* / pathology
  • Cholesterol
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Liver Neoplasms* / metabolism
  • Mechanistic Target of Rapamycin Complex 1 / metabolism
  • Non-alcoholic Fatty Liver Disease* / genetics
  • RNA, Long Noncoding / genetics*
  • RNA, Long Noncoding / metabolism

Substances

  • RNA, Long Noncoding
  • long non-coding RNA SNHG6, human
  • Cholesterol
  • Mechanistic Target of Rapamycin Complex 1