Effects of SmacN7 on apoptosis in human pancreatic cancer cell line SW1990

OBJECTIVE:To observe the effect of SmacN7 of exogenous Smac small molecule group on the apoptosis of human pancreatic cancer cell line SW1990 and wish to look for a new option for pancreatic cancer treatment.METHODS: 1)SmacN7 was prepared through solid-phase peptide synthesis technique and RP-HPLC;2)Apoptosis cell morphology of SW1990 treated with 500 μg/mL SmacN7 and TRAIL for 24 hours was observed with Heochst 33342 staining.3)Cell circle distribution SW1990 treated with SmacN7 and TRAIL was assayed with flow cytometry;4)SW1990 growth inhibition rate from different concentration and acting time of SmacN7 were assayed with MTT.RESULTS: 1)The purity of SmacN7 was more than 95%,with molecular weight of 3 278.08;2)Treatment of the SW1990 cells for 24 h with 500 μg/mL of SmacN7 and 500 ng/mL of TRAIL yielded similar results,including cell volume and nuclei enlargement with mild swelling,cells shorten and spindled,blue bright of nuclei and leaf-like or fragmented with edge concentration.Cell circle analysis showed that cells were blocked at G0/G1 stage,the proportion of S phage was decreased and cell growth was slowed down.3)The CAR of SW1990 was 15.3% after 24 h SmacN7 treatment,significantly higher than that of TRAIL treatment(5.64%).4)Along with different concentration of SmacN7(50,100,200 and 500 μg/mL) at different duration of treatment(24,48 and 72 h),CGIR were elevated with concentration increment and elongation of time(P0.05).5)Treatment with 500 μg/mL of SmacN7 combined with different concentration of TRAIL(200,500,1 000 and 2 500 ng/mL) and GEM(10,20,40 and 60 μmol/L),the CGIR percentage were increased with the concentration elevation(18.11%,37.67%,42.63% and 67.60% in TRAIL,17.65%,31.85%,40.11% and 74.99% in GEM respectively).CONCLUSIONS: SmacN7 can induce pancreatic cancer cell apoptosis in a concentration-and time-dependent manner,decreased expression of XIAP and increased expression of Cyto C and p17 of Caspase-3 bio-active fragment may be the underlying mechanism.SmacN7 may become a new option for pancreatic cancer treatment.