Objective   To study the effect of sodium 4-phenylbutyrate (SPB) and all transretinoic acid (ATRA)

two histone deacetylase inhibitors

on invasion ability of cervical cancer Hela cells.    Methods    Cervical cancer Hela cells cultured in vitro were divided into groups A-D as 1 ml PBS treatment group （control group）

1 μmol/L ATRA treatment group

1 mmol/L SPB treatment group

and 1 μmol/L ATRA plus 1 mmol/L SPB treatment group

respectively. Cell growth curve

MTT and c

lonogenic assay in vitro were used to observe the inhibitory effects of SPB and ATRA on cell proliferation. Distribution of cell cycles was detected by flow cytometry

and invasion ability of Hela cells was determined by Transwell chamber assay.    Results    The growth of Hela cells was significantly slower in 1 μmol/L ATRA +1 mmol/L SPB treatment group than in control and 1 μmol/L ATRA treatment group or 1 mmol/L SPB treatment group

with an inhibition rate of colony formation of 80.37% (P0.05). The cell cycle was arrested at the G

0

/G

1

phase

the number of cells in S phase was decreased after combined treatment with SPB with ATRA．The invasion ability of Hela cells was significantly weaker in 1 μmol/L ATRA +1 mmol/L SPB treatment group than in control group and  1 μmol/L ATRA treatment group or 1 mmol/L SPB treatment group (P0.05).    Conclusion   SPB and ATRA used in combination have an obvious synergistic effect on the invasion ability of cervical cancer Hela cells.