Aldo-keto reductase family 1 B10 affects fatty acid synthesis by regulating the stability of acetyl-CoA carboxylase-alpha in breast cancer cells

J Biol Chem. 2008 Feb 8;283(6):3418-3423. doi: 10.1074/jbc.M707650200. Epub 2007 Dec 1.

Abstract

Recent studies have demonstrated that aldo-keto reductase family 1 B10 (AKR1B10), a novel protein overexpressed in human hepatocellular carcinoma and non-small cell lung carcinoma, may facilitate cancer cell growth by detoxifying intracellular reactive carbonyls. This study presents a novel function of AKR1B10 in tumorigenic mammary epithelial cells (RAO-3), regulating fatty acid synthesis. In RAO-3 cells, Sephacryl-S 300 gel filtration and DEAE-Sepharose ion exchange chromatography demonstrated that AKR1B10 exists in two distinct forms, monomers (approximately 40 kDa) bound to DEAE-Sepharose column and protein complexes (approximately 300 kDa) remaining in flow-through. Co-immunoprecipitation with AKR1B10 antibody and protein mass spectrometry analysis identified that AKR1B10 associates with acetyl-CoA carboxylase-alpha (ACCA), a rate-limiting enzyme of de novo fatty acid synthesis. This association between AKR1B10 and ACCA proteins was further confirmed by co-immunoprecipitation with ACCA antibody and pulldown assays with recombinant AKR1B10 protein. Intracellular fluorescent studies showed that AKR1B10 and ACCA proteins co-localize in the cytoplasm of RAO-3 cells. More interestingly, small interfering RNA-mediated AKR1B10 knock down increased ACCA degradation through ubiquitination-proteasome pathway and resulted in >50% decrease of fatty acid synthesis in RAO-3 cells. These data suggest that AKR1B10 is a novel regulator of the biosynthesis of fatty acid, an essential component of the cell membrane, in breast cancer cells.

Publication types

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

MeSH terms

  • Acetyl-CoA Carboxylase / chemistry*
  • Acetyl-CoA Carboxylase / metabolism
  • Aldehyde Reductase / genetics
  • Aldehyde Reductase / physiology*
  • Aldo-Keto Reductases
  • Breast Neoplasms / metabolism*
  • Cell Line, Tumor
  • Cell Membrane / metabolism
  • Cytoplasm / metabolism
  • Fatty Acids / metabolism
  • Gene Expression Regulation, Neoplastic*
  • Gene Silencing
  • Humans
  • Proteasome Endopeptidase Complex / metabolism
  • RNA, Small Interfering / metabolism
  • Recombinant Proteins / chemistry
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
  • Ubiquitin / metabolism

Substances

  • Fatty Acids
  • RNA, Small Interfering
  • Recombinant Proteins
  • Ubiquitin
  • AKR1B10 protein, human
  • Aldo-Keto Reductases
  • Aldehyde Reductase
  • Proteasome Endopeptidase Complex
  • Acetyl-CoA Carboxylase