Methyl protodioscin induces G2/M arrest and apoptosis in K562 cells with the hyperpolarization of mitochondria

Ming Jie Liu, Patrick Y K Yue, Zhao Wang, Ricky N S Wong*

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

70 Citations (Scopus)


Methyl protodioscin is a furostanol bisglycoside with antitumor properties. The present study investigated its effects on human chronic myelogenous leukemia K562 cells. Cell cycle analysis showed that methyl protodioscin caused distinct G2/M arrest, with the appearance of polyploidy population. The levels of cyclin B1 decreased, whereas Cdc2 kept at a steady level. Subsequent apoptosis after G2/M blockage was demonstrated through DNA fragmentation and the annexin V staining assay. Methyl protodioscin induced a biphasic alteration (i.e. an early hyperpolarization, followed by depolarization) in mitochondrial membrane potential of K562 cells. The transient decline of intracellular Ca2+ concentration was observed at early stage. The generation of reactive oxygen species was also detected. The anti-apoptotic Bcl-xL transiently increased and then decreased. And the pro-apoptotic Bax was markedly up-regulated. Taken together, these data demonstrated that methyl protodioscin inhibits K562 cell proliferation via G2/M arrest and apoptosis, with mitochondrial hyperpolarization and the disruption of Ca2+ homeostasis playing important roles.

Original languageEnglish
Pages (from-to)229-241
Number of pages13
JournalCancer Letters
Issue number2
Publication statusPublished - 28 Jun 2005

Scopus Subject Areas

  • Oncology
  • Cancer Research

User-Defined Keywords

  • Apoptosis
  • Ca homeostasis
  • G2/M arrest
  • Methyl protodioscin
  • Mitochondrial hyperpolarization


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