Inhibitory effect of soluble CD40 ligand combined with LY294002 on growth of gastric cancer cells

Abstract

Objective To investigate the effects of soluble CD40 ligand combined with LY294002,a specific inhibitor of phosphatidylinositol 3 kinase (PI3K),on the proliferation and apoptosis of gastric cancer cells (AGS),and its potential mechanisms.Methods The effect of gradient concentration of soluble CD40 ligand (sCD40L) and its combination with LY294002 on cellular proliferation was determined by using methyl thiazol tetrazolium (MTT) assay.The cellular cycle and apoptosis were evaluated by flow cytometry (FCM).The cellular morphologic change was detected by election microscope.The protein expression of PI3K and p-protein kinase B (p-Akt) was tested by using Western blotting.Results The inhibitory rate of cellular proliferation in LY294002,sCD40L and LY294002 + sCD40L groups was (65.72 ±3.19)％,(70.14 ±2.98)％ and (41.25 ±2.74)％ respectively (P ＜0.05).The cellular cycle arrest was increased in cells treated with sCD40L plus LY294002 when compared with those treated with sCD40L or LY294002 alone (P ＜ 0.05).LY294002 could increase cellular apoptosis with the apoptosis rate being (8.97 ± 1.23) ％,and sCD40L did not obviously increase cellular apoptosis with the apoptosis rate bing (4.23 ± 0.74)％.As compared with LY294002 alone,the rate of cellular apoptosis was increased obviously after being treated by LY294002 in combination with sCD40L with the apoptosis rate being (29.32 ±2.37)％ (P ＜0.05).The protein expression of PI3K and p-Akt was increased in cells treated with sCD40L,but reduced drastically in those treated with sCD40L plus LY294002 (P ＜ 0.05).Conclusion Inhibiting PI3K/Akt signaling pathway can enhance the inhibitory effect of proliferation by sCD40L on AGS,which may provide a new way for biochemical therapy of gastric cancer. Key words: Gastric cancer; Soluble CD40 ligand; Phosphatidylinositol 3 kinase/protein kinase B pathway; Tumor treatment