The Effect On The Growth And Radiation Of Human Cervical Carcinoma Cells By Histone Deacetylases Inhibitor And HDAC-1 SiRNA

Objective: To explore the role of histone deacetylases (HDACs) inhibitor, sodium valproate and HDAC-1 siRNA in the growth, cell cycle and apoptosis of cervical carcinoma cells. To investigate the effect of sodium valproate and HDAC-1 siRNA on the radiosensitivity of cervical carcinoma cells.Methods: Hela and Siha cells were cultured in vitro. The subjects were divided into 6 groups: Hela control group, Hela sodium valproate group, Siha control group, Siha sodium valproate group, Hela siRNA control group, Hela HDAC-1 siRNA group. Three HDAC-1 sequence-specific siRNAs were designed and transiently transfected into Hela cells. The knockdown of HDAC-1 protein was detected by Western blotting. The HDAC-1 siRNA sequence with the best knockdown effect was selected for the next research. The cell growth inhibition ratio of each group were assessed by MTT assay. The cell cycle and apoptosis ratio were detected by flow cytometer. The HDAC-1,p21WAF1/CIP1, p-CDK2, cyclinE,Ku70,Ku80 protein were examined by western blot, and p21WAF1/ CIP1 mRNA was examined by RT-PCR. Radiosensitivity effect of sodium valproate and HDAC-1 siRNA were detected by cell colony formation methods. The D0, SF2 and sensitizing enhancement ratio(SER) of each group and the cell survival curves were gained by single-hit multi-target model.Results:⑴Sodium valproate inhibited he proliferation of Hela and Siha cells in a dose dependent manner.⑵Hela and Siha cells showed cell cycle changes and a G0/G1 phase arrest in response to sodium valproate.⑶In Hela and Siha cells treated with sodium valproate, accumulation of p21WAF1/ CIP1 in protein and mRNA level and reduced protein level of p-CDK2 were detected. The cyclinE protein was up-regulated in Hela cells and down-regulated in Siha cells.⑷All of the three HDAC-1 siRNAs down-regulated the expression of HDAC-1 protein with different inhibition ratio. The HDAC-1 siRNA 001 sequence showed the highest inhibition ratio(80%) at 48h post-transfection.⑸HDAC-1 siRNA transfection inhibited the proliferation of Hela cells.⑹HDAC-1 siRNA transfection induced apoptosis in Hela cells.⑺HDAC-1 siRNA transfection up-regulated p21WAF1/ CIP1 and cyclinE protein and down-regulated p-CDK2.⑻In Hela and Siha cells, the D0 and SF2 of the sodium valproate + radiation group were lower than the radiation group, and the SER were 1.1286 and 2.1547 respectively.⑼Sodium valproate down-regulated Ku80 protein in Siha cells with or without radiation and in Hela cells with radiation.⑽There were G2/M phase accumulation, S phase increase and G0/G1 phase reduction in Siha cells with radiation; Sodium valproate reduced the accumulation of G2/M phase, down-regulated S phase ratio and induced G0/G1 phase arrest.⑾HDAC-1 siRNA did not changed the D0 and SF2 and had not radiosensitivity role in Hela cells.⑿HDAC-1 siRNA did not affect the expression of Ku70 and Ku80 protein.Conclusions:⑴Sodium valproate may play an anti-proliferation role by raising p21WAF1/ CIP1 protein, inhibiting the phosphatization of CDK2 and inducing G0/G1 phase arrest.⑵HDAC-1 siRNA may knockdown the HDAC-1 protein and inhibit the growth of Hela cells by inducing apoptosis.⑶Sodium valproate radiosensitized Hela and Siha cells. The possible mechanisms are down-regulation of Ku80 protein, G0/G1 phase arrest and reduction of G2/M accumulation induced by radiation.⑷HDAC-1 siRNA did not radiosensitize Hela cells.