title: Effects of griseofulvin on apoptosis through caspase-3- and caspase-9-dependent pathways in K562 leukemia cells: An in vitro study.
abstract: BACKGROUND
  Griseofulvin, an oral nontoxic antifungal drug, has been reported to possess anticancer effect in human cancer cells, while the mechanisms are not completely understood.
  
  
  OBJECTIVE
  The aim of this study was to investigate the cytotoxic effect of griseofulvin on K562 cells and to understand its underlying molecular pathways.
  
  
  METHODS
  K562 cells were treated with griseofulvin at different concentrations for 24 hours, and the inhibition effect of griseofulvin on K562 cell proliferation was assessed by tetrazolium salt colorimetric assay. Apoptosis was assessed by examining nuclear morphology and quantifying phosphatidylserine externalization, and alterations in cellular morphology were analyzed by laser scanning confocal microscopy for fluorescent analysis. Flow cytometry was used in the analysis of cell cycle, mitochondrial membrane potential, and caspase pathways.
  
  
  RESULTS
  Griseofulvin could inhibit the growth of K562 cells in a dose-dependent manner with a mean (SD) inhibitory concentration of 50% value of 15.38 (1.35) μg/mL compared with untreated controls. Apoptosis was induced in K562 cells (38.35% [2.73%]; P < 0.01) by griseofulvin with the observation of both an increase in phosphatidylserine level and accumulation of chromatin nucleation in griseofulvintreated cells. In addition, cell-cycle analysis using propidium iodide staining suggested a significant G2/M accumulation (increase from mean 17.64% [4.49%] to 48.29 [1.89%]; P < 0.01) as a result of griseofulvin treatment. Flow cytometry analysis found that griseofulvin treatment was associated with the depolarization of the mitochondrial membrane in K562 cells. Furthermore, increased activities of caspase-3 by 22.15-fold (P < 0.01) and caspase-9 by 16.73-fold (P < 0.01) were observed in K562 cells after griseofulvin treatment compared with the untreated control; a decrease of caspase-8 activity was also observed, but the change was not statistically significant.
  
  
  CONCLUSIONS
  These findings suggest that griseofulvin inhibited growth of K562 cells and induced cell apoptosis through cell-cycle arrest and mitochondrial membrane potential decrease as well as caspase-3 and -9 activation. Further testing is needed to evaluate the potential of griseofulvin as a candidate in the chemotherapy of hematologic malignancies.
authors.affiliation: Department of Surgery, The First People's Hospital of Kunshan City, Kunshan, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Zhong
authors.affiliation: Department of Medicine, University of Chicago, Chicago, Illinois.
authors.forename: Hankui
authors.initials: H
authors.lastname: Chen
authors.affiliation: The Affiliated Hospital, Shandong Tradition Chinese Medicine University, Shandong, China.
authors.forename: Quanlin
authors.initials: Q
authors.lastname: Zhao
authors.affiliation: Department of Medicine, University of Chicago, Chicago, Illinois.
authors.forename: Hongwei
authors.initials: H
authors.lastname: Wang
authors.affiliation: Wuxi Blood Center, Wuxi, Jiangshu, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Yu
authors.affiliation: Department of Medicine, University of Chicago, Chicago, Illinois.
authors.forename: Ashley M
authors.initials: AM
authors.lastname: Eaves
authors.affiliation: Department of Cell Biology, School of Medicine, Soochow University, Suzhou, China.
authors.forename: Weihua
authors.initials: W
authors.lastname: Sheng
authors.affiliation: Department of Cell Biology, School of Medicine, Soochow University, Suzhou, China.
authors.forename: Jingcheng
authors.initials: J
authors.lastname: Miao
authors.affiliation: Department of Cell Biology, School of Medicine, Soochow University, Suzhou, China.
authors.forename: Fengmei
authors.initials: F
authors.lastname: Cui
authors.affiliation: Department of Cell Biology, School of Medicine, Soochow University, Suzhou, China.
authors.forename: Jinzhi
authors.initials: J
authors.lastname: Wang
keywords: K562 cells; apoptosis; caspase-3; caspase-9; griseofulvin