Effect Of Curcumin On HIF-1α And VEGF Expression In Hepatocellular Carcinoma Hep1 Cells

Objective To study the effect of curcumin on hypoxia-inducible factor-1α(HIF-1α) and vascular endothelial growth factor(VEGF) expression in hepatocellular carcinoma Hep1 cell in normal oxygen conditions,and explore effect of curcumin on growth, apoptosis and cycle phase of Hep1 cells.Subjects We selected human SK-Hep1 hepatoma cell line in which HIF-1αexpression could also be higher in normal oxygen conditions, and cultured them in 37℃, saturated humidity,5%CO2 and normal partial pressure of oxygen environment. When the cells were in logarithmic growth phase,the experiment began. Hep1 cells were treated with different concentrations of curcumin (final concentration, respectively 0μmol/L,5μmol/L, 10μmol/L 15μmol/L,20μmol/L). HIF-1αand VEGF mRNA expression in Hep1 cell was measured by RT-PCR.HIF-1αand VEGF protein expression in Hepl cell was measured by Western blotting. Effect of curcumin on Hep1 cell proliferation was observed by CCK-8, and then we drawed the growth curve and calculated the inhibitory rate of cell proliferationResults In normal oxygen conditions,compared with that in the blank control group, HIF-1αand VEGF expression of mRNA in Hep1 cells were significantly up-regulated after Hep1 cells were treated with 10μmol/L 15μmol/L,20μmol/L of curcumin for 24 hours, and the difference was statistically significant (P<0.05), while the difference between that in the experimental control group (curcumin 0μmol/L, by adding an equivalent DMSO), curcumin 5μmol/L group and blank control group was not statistically significant (P>0.05). HIF-1αand VEGF protein expression in curcumin 5μmol/L,10μmol/L,15μmol/L,20μmol/L were significantly higher than that in blank control group in concentration-dependent manner (P<0.01).(2) Compared with that in the control group, cell proliferation in curcumin treatment groups (5μmol/L, 10μmol/L,15μmol/L,20μmol/L) was inhibited in different degrees, especially more significant in 10,15,20μmol/L group,and the differences were all statistically significant (P<0.01), while cell proliferation in the experimental control group (curcumin 0μmol/L, by adding an equivalent DMSO) was not significantly different (P> 0.05). (3) 48-hour cell apoptosis rates in blank control group, experimental control group and 15μmol/L curcumin group were 4.50±0.15%,4.72±0.70%,9.93±0.88%. Compared with that in the control group, the apoptosis rate of Hep1 in experimental control group had not statistically significant difference (P>0.05), while that in 15±mol/L curcumin group was significantly higher (P<0.05).(4) Compared with that in the control group, G0+G1 phase cells in curcumin 15±mol/L Group were significantly increased, while G2+M phase cells were significantly reduced, and the difference was statistically significant (P<0.05).Conclusions (1) In normal oxygen conditions, curcumin increases HIF-la and VEGF expression of hepatocellular carcinoma Hepl cells in a concentration- dependent manner.(2) In normal oxygen conditions, the mechanisms of curcumin regulating HIF-la expression of hepatocellular carcinoma Hep1 cells is different from that in hypoxia conditions, curcumin upregulating VEGF expression in Hep1 cells may be related to that curcumin increases HIF-1αexpression.(3) In normal oxygen conditions, curcumin can effectively inhibit growth and proliferation of Hep1 hepatocellular carcinoma cells with a clear dose-response relationship, and the mechanism may be interfering with cell cycle progression and promoting apoptosis.