Regulation of survivin and Bcl-2 in HepG2 cell apoptosis induced by quercetin

Chem Biodivers. 2009 Jul;6(7):1101-10. doi: 10.1002/cbdv.200800141.

Abstract

Quercetin, a widely distributed bioflavonoid, has been shown to induce growth inhibition in a variety of human cancer cells. However, the regulation of survivin and Bcl-2 on the quercetin-induced cell-growth inhibition and apoptosis in cancer cells remains unclear. In the present study, we report that quercetin can inhibit proliferation and induce apoptosis in HepG2 cells in dose- and time-dependent manner. Hoechst 33258 and acridine orange/ethidium bromide (AO/EB) staining showed that HepG2 cells underwent the typical morphologic changes of apoptosis characterized by nuclear shrinkage, chromatin condensation, or fragmentation after exposure to quercetin. Cell-cycle analysis reveals a significant increase of the proportion of cells in G(0)/G(1) phase. We also demonstrate that the levels of survivin and Bcl-2 protein expression in HepG2 cells decreased concurrently, and the levels of p53 protein increased significantly after treatment with quercetin by immunocytochemistry analysis. Relative activity of caspase-3 and caspase-9 increased significantly. These data clearly indicate that quercetin-induced apoptosis is associated with caspase activation, and the levels of survivin and Bcl-2. Our results indicate that the expression of survivin may be associated with Bcl-2 expression, and the inhibition expression of survivin, in conjunction with Bcl-2, might cause more pronounced apoptotic effects. Together, concurrent down-regulated survivin and Bcl-2 play an important role in HepG2 cell apoptosis induced by quercetin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / pharmacology*
  • Apoptosis*
  • Caspase 3 / metabolism
  • Caspase 9 / metabolism
  • Cell Line, Tumor
  • G1 Phase
  • Humans
  • Inhibitor of Apoptosis Proteins
  • Microtubule-Associated Proteins / metabolism*
  • Proto-Oncogene Proteins c-bcl-2 / metabolism*
  • Quercetin / pharmacology*
  • Resting Phase, Cell Cycle
  • Survivin

Substances

  • Antineoplastic Agents
  • BIRC5 protein, human
  • Inhibitor of Apoptosis Proteins
  • Microtubule-Associated Proteins
  • Proto-Oncogene Proteins c-bcl-2
  • Survivin
  • Quercetin
  • Caspase 3
  • Caspase 9