Study On The Anti-tumor Activity Of TRAIL On Gastric Cancer Cells

Objective: To study the apoptosis-inducing activity of TRAIL on gastric cancer cells MKN28, MKN45, AGS and SGC-7901, and to investigate the expressions of apoptosis-related regulator genes, including NF-кB, survivin, Bcl-2 and Caspase3 in these four cell lines.Meanwhile, we observed the effect of a combination of α-Tocopheryl succinate (α-TOS) and TRAIL, or sodium nitroprusside(SNP) and TRAIL on the apoptosis of gastric cancer cells and their effects on the expression of NF-к B,survivin and Bcl-2.Methods: Apoptosis of gastric cancer cells induced by TRAIL was analysized with PI staining method and flow cytometry (FCM); the expressions of NF- кB,survivin, Bcl-2 and Caspase3 were observed Using Western blot method in the four gastric cancer cell lines.Results: (1) After the gastric cancer cells were exposed to TRAIL 300ng/ml for 24 hours, the apoptosis rate was 36.05%, 20.37%, 16.50% and 11.80% in MKN28, MKN45, AGS and SGC-7901 cells respectively. The sensitivity to TRAIL in MKN28 cells was significantly higher than that in MKN45, AGS and SGG7901 cells(p<0.05). (2)Western blot revealed that the expressions of NF-к B and survivin were lower in MKN28 cells than in MKN45,AGS and SGC-7901 cells. In contrast, the expression of Caspase3 was higher in MKN28 cells than in MKN45, AGS and SGG7901 cells and the expression of Bcl-2 had no difference among the four cell lines. (3) When SGG7901 cells and MKN28 cells were exposed to α -TOS 60 mol/1 for 24 hours, the apoptosis rate was 9.0% in MKN28, 8.5% in SGC-7901, while treatment of SGC-7901 cells and MKN28 cells with a combination of u -TOS 60 mol/1 and TRAIL 300ng/ml for 24 hours , the apoptosis rate was 48.1% and 63.7% respectively.When the cells were exposed to α -TOS alone, the level of Bcl-2 and survivin was decreased. Theα-TOS and TRAIL combination decreased the expression of NF- кB, Bcl-2 and survivin in gastric cancer cells.(4) Treatment of SGG7901 cells and MKN28 cells with a combination of SNP2.0mM and TRAIL 300ng/ml for 24 hours, the apoptosis rate was 41.92% and 63.77% respectively, but treatment with SNP alone can not induce SGC-7901 and MKN28 cells to undergo apoptosis. SNP administration could decrease the expression of survivin, but could not decrease the expression of NF-к B in gastric cancer cells. Moreover, SNP and TRAIL combination can decreased the expression of NF- кB and survivin in SGC-7901 cells and MKN28 cellsConclusions: (1) There is a selectivity of TRAIL potency to induce apoptosis in gastric cancer cells of different cell lines. SGG7901 cells was most insensitive to TRAIL while MKN28 cells was most sensitive. (2)The anticancer potency of TRAIL is associated with the decreased expressions of NF- кB and survivin and the increased expression of Caspase3 of the gastric cancer cells.(3) alpha-TOS is a strong inducer of apoptosis and exerted a cooperative proapoptotic activity with TRAIL due to the inhibition of expression of NF- кB, Bcl-2 and survivin.(4) SNP alone could not induce apoptosis but it could enhance the activity of TRAIL through inhibition of the expression ofsurvivin in gastric cancer cells.