Histone Deacetylase Inhibitor-FK228 Inhibits the Spindle Checkpoint Function of Human Non-small-cell Lung Cancer A549 Cells

Abstract: HDACi-FK228 is a novel and promising anticancer drug. However， the underlying molecular mechanism has not been well clarified. In this study， we investigated the effect of FK228 on the spindle checkpoint function of human non-small-cell lung cancer A549 cells. Using the flow cytometry to detect the influence of FK228 on the A549 cell cycle; Using immunofluorescence staining to detect the centromeric localization of checkpoint protein Bub1 and BubR1 and using Western blot to examine the checkpoint protein expression; The spindle checkpoint function of A549 cells after the FK228 treatment was determined by the spindle checkpoint function experiment. The results revealed that FK228 increased the G2/M ratio of cells from 6.35% to 19.91% after 24 h treatment; In addition， FK228 inhibited the centromeric localization of Bub1 and BubR1 protein. However， western blot analysis indicated that FK228 treatment induced the protein expression of the Bub1 and BubR1. Spindle checkpoint experiment indicated that the G2/M ratio in control group were increased highest to 35.74% by Nocodazole or 29.24% by Taxol treatment， while the G2/M ratio of FK228 group by Nocodazole or Taxol treatment in all the time point were decreased， for the highest is 7.13% by Nocodazole and 6.03% by Taxol treatment， which indicates that FK228 treatment inhibited the spindle checkpoint function of the A549 cells. Our data implicate that FK228 can inhibit the spindle checkpoint proteins Bub1 and BubR1 centromeric localization and inhibit the spindle checkpoint function of the A549 cells， which might be the possible reason of FK228 induced abnormal mitosis. This study contributes to elucidate the possible mechanism of FK228 to kill tumor cells.

CSTR: 32200.14.cjcb.2013.10.0008