Growth effect of UDCA on hepatocarcinoma cell line HepG2 by regulating the expression of Caspase-3 and Survivin

Objective to investigate the effects of UDCA on the growth and expression of Survivin, Caspase-3 of human hepatoma carcinoma (HCC) cellline HepG2, and to discuss the possible mechanism. Methods I-ICC cell line HepG2 was treated by UDCA in 12.5, 25, 50, 100,200,400μg/ml respectively,and was detected at 6, 12, 18,24,48, 72h by MTT assay, flow cytometry (FCM) with PI staining or Annexin V-FITC/PI double stainings, optical microscope,laser scanning confocal microscopy, semiquantitative RT-PCR. Results Cell proliferation was blocked by UDCA, which showed significant positive association with the concentration and the duration of UDCA treatment(6h,r=0.9775,P0.01; 12h, r=0.8743,P0.05; 24h, r=0.9259, P0.01; 36h, r=0.9499, P0.01; 72h, r=0.8352, P0.05). Optical microscope showed that the amount of round, small and dead cells increased after treated by UDCA. Laser confocal microscopy also showed the presence of apoptosis of cells after the treatment. FCM analysis showed that the apoptotic effect of UDCA on cell line HepG2 was concentration-and time-dependent. On the concentration of 200 mg/ml ,it was after 6h that apoptosis rate, (12.17+1.76)%, began to rise,singnificantly higher than that of control group,(7.92+1.15)%. And at 24h, apoptosis rate of treatment group was higher than that of control group was P0.01. After 24 hours treated by UACA, on the concentration of 200ug/ml, the ratio of S-phase of control group was (48.09±2.31) % , higher than that of control group (21.83± 2.21)%, P0.01.The longer UDCA treated, the less Survivin mRNA expressed ,and the more that of Caspase-3 expressed. There was correlation between the expression of Survivin with Caspase-3 (r=-0.9959,P0.01), cellular proliferation (r=0.9883, P0.05), or apoptosis index (r=-0.9521,P0.05)in our study.Conclusion The mechanism of UDCA inhibiting cellular proliferation and inducing apoptosis of HCC line HepG2 may possibly relate to influencing the expression of Survivin which inhibits the activity of Caspase-3.