HIF drives lipid deposition and cancer in ccRCC via repression of fatty acid metabolism

Nat Commun. 2017 Nov 24;8(1):1769. doi: 10.1038/s41467-017-01965-8.

Abstract

Clear cell renal cell carcinoma (ccRCC) is histologically defined by its lipid and glycogen-rich cytoplasmic deposits. Alterations in the VHL tumor suppressor stabilizing the hypoxia-inducible factors (HIFs) are the most prevalent molecular features of clear cell tumors. The significance of lipid deposition remains undefined. We describe the mechanism of lipid deposition in ccRCC by identifying the rate-limiting component of mitochondrial fatty acid transport, carnitine palmitoyltransferase 1A (CPT1A), as a direct HIF target gene. CPT1A is repressed by HIF1 and HIF2, reducing fatty acid transport into the mitochondria, and forcing fatty acids to lipid droplets for storage. Droplet formation occurs independent of lipid source, but only when CPT1A is repressed. Functionally, repression of CPT1A is critical for tumor formation, as elevated CPT1A expression limits tumor growth. In human tumors, CPT1A expression and activity are decreased versus normal kidney; and poor patient outcome associates with lower expression of CPT1A in tumors in TCGA. Together, our studies identify HIF control of fatty acid metabolism as essential for ccRCC tumorigenesis.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Basic Helix-Loop-Helix Transcription Factors / genetics
  • Basic Helix-Loop-Helix Transcription Factors / metabolism*
  • Carcinogenesis
  • Carcinoma, Renal Cell / genetics
  • Carcinoma, Renal Cell / metabolism*
  • Carnitine O-Palmitoyltransferase / genetics
  • Carnitine O-Palmitoyltransferase / metabolism
  • Cell Line, Tumor
  • Fatty Acids / metabolism*
  • Female
  • Humans
  • Hypoxia-Inducible Factor 1, alpha Subunit / genetics
  • Hypoxia-Inducible Factor 1, alpha Subunit / metabolism*
  • Kidney Neoplasms / genetics
  • Kidney Neoplasms / metabolism*
  • Mice, Inbred BALB C
  • Mice, Nude
  • Mitochondria / metabolism

Substances

  • Basic Helix-Loop-Helix Transcription Factors
  • Fatty Acids
  • HIF1A protein, human
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • endothelial PAS domain-containing protein 1
  • CPT1A protein, human
  • Carnitine O-Palmitoyltransferase