Oleanolic acid derivative NPLC441 potently stimulates glucose transport in 3T3-L1 adipocytes via a multi-target mechanism

Biochem Pharmacol. 2008 Nov 15;76(10):1251-62. doi: 10.1016/j.bcp.2008.08.016. Epub 2008 Aug 22.

Abstract

The natural product oleanolic acid (OA) has been discovered to exhibit varied pharmacological functions including anti-inflammation, anti-tumor and anti-diabetes, while appropriate synthetic oleanolic acid derivatives seem to possess more potent activities. Here we identified a new oleanolic acid derivative, 3-beta-(2-carboxybenzoyloxy)-oleanolic acid (NPLC441), which functioned as a competitive PTP1B inhibitor and enhanced insulin-stimulated phosphorylation of IR and AKT in HepG2 cells. As an RXRalpha antagonist, it could selectively activate LXRalpha:RXRalpha heterodimer and increase the promoter activities of ABCA1 and ABCG1 genes in transient transfection assays. Quantitative RT-PCR and Western blot analyses suggested that NPLC441 could up-regulate GLUT4 expression in 3T3-L1 adipocytes, and such effect was further proved to be dependent on LXRalpha:RXRalpha activation. Moreover, 2-deoxyglucose uptake technology-based characterization demonstrated that this compound could stimulate glucose uptake in 3T3-L1 adipocytes. Finally, NPLC441 was observed to be able to suppress 11beta-HSD(1) expression in HepG2 cells, following the discovery that activation of LXRalpha:RXRalpha could repress the expression of 11beta-HSD(1). Compared with NPLC441, OA showed no effects on the transactivation of either LXRalpha:RXRalpha heterodimer or RXRalpha-LBD. Our work is thus expected to provide a new insight into the anti-diabetic application for oleanolic acid derivatives via multi-target mechanism, and NPLC441 could be used as a potential lead compound for further research.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3T3-L1 Cells
  • Adipocytes / drug effects
  • Adipocytes / metabolism*
  • Animals
  • Biological Transport / drug effects
  • Biological Transport / physiology
  • Cell Line
  • Glucose / agonists
  • Glucose / metabolism*
  • Glucose Transport Proteins, Facilitative / agonists
  • Glucose Transport Proteins, Facilitative / metabolism
  • Humans
  • Mice
  • Oleanolic Acid / analogs & derivatives*
  • Oleanolic Acid / pharmacology*
  • Protein Tyrosine Phosphatase, Non-Receptor Type 1 / antagonists & inhibitors
  • Protein Tyrosine Phosphatase, Non-Receptor Type 1 / metabolism

Substances

  • Glucose Transport Proteins, Facilitative
  • Oleanolic Acid
  • Protein Tyrosine Phosphatase, Non-Receptor Type 1
  • Ptpn1 protein, mouse
  • Glucose