The roles of endoplasmic reticulum stress and Ca2+ on rhein-induced apoptosis in A-549 human lung cancer cells

Anticancer Res. 2009 Jan;29(1):309-18.

Abstract

Although rhein has been shown to induce apoptosis in several cancer cell lines, the mechanism of action of rhein-induced cell cycle arrest and apoptosis at the molecular level is not well known. In this study, the mechanism of rhein action on A-549 human lung cancer cells was investigated. Rhein induced G0/G1 arrest through inhibition of cyclin D3, Cdk4 and Cdk6. The efficacious induction of apoptosis was observed at 50 microM for 12 h and up to 72 h as examined by a flow cytometric method. Flow cytometric analysis demonstrated that rhein increased the levels of GADD153 and GRP78, both hallmarks of endoplasmic reticulum stress, promoted ROS and Ca2+ production, induced the loss of mitochondrial membrane potential (delta psi(m)), promoted cytochrome c release from mitochondria, promoted capase-3 activation and led to apoptosis. Rhein also increased the levels of p53, p21 and Bax but reduced the level of Bcl-2. The Ca2+ chelator BAPTA was added to the cells before rhein treatment, thus blocking the Ca2+ production and inhibiting rhein-induced apoptosis in A-549 cells. Our data demonstrate that rhein induces apoptosis in A-549 cells via a Ca2+ -dependent mitochondrial pathway.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anthraquinones / pharmacology*
  • Apoptosis / drug effects*
  • Apoptosis / physiology
  • Blotting, Western
  • Calcium / metabolism*
  • Caspase Inhibitors
  • Cell Line, Tumor
  • Cyclin D3
  • Cyclin-Dependent Kinase 4 / antagonists & inhibitors
  • Cyclin-Dependent Kinase 6 / antagonists & inhibitors
  • Cyclins / antagonists & inhibitors
  • Egtazic Acid / analogs & derivatives
  • Egtazic Acid / pharmacology
  • Endoplasmic Reticulum / drug effects*
  • Endoplasmic Reticulum / metabolism
  • Endoplasmic Reticulum Chaperone BiP
  • Enzyme Inhibitors / pharmacology
  • Flow Cytometry
  • G1 Phase / drug effects
  • Humans
  • Lung Neoplasms / drug therapy*
  • Lung Neoplasms / metabolism
  • Lung Neoplasms / pathology
  • Membrane Potential, Mitochondrial / drug effects
  • Microscopy, Confocal
  • Oligopeptides / pharmacology
  • Reactive Oxygen Species / metabolism
  • Resting Phase, Cell Cycle / drug effects

Substances

  • Anthraquinones
  • CCND3 protein, human
  • Caspase Inhibitors
  • Cyclin D3
  • Cyclins
  • Endoplasmic Reticulum Chaperone BiP
  • Enzyme Inhibitors
  • HSPA5 protein, human
  • Oligopeptides
  • Reactive Oxygen Species
  • benzoylcarbonyl-aspartyl-glutamyl-valyl-aspartyl-fluoromethyl ketone
  • Egtazic Acid
  • CDK4 protein, human
  • CDK6 protein, human
  • Cyclin-Dependent Kinase 4
  • Cyclin-Dependent Kinase 6
  • 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid
  • Calcium
  • rhein