Inhibition of PKC-? enhances the toxicity of TNF-? to H22 cell Lines / 中国普通外科杂志

ABSTRACT

Objective To investigate the effect of tumor necrosis factor alpha ( TNF-?) in combination with Go6976 on murine liver cancer cells (H22). Method H22 cells were divided into two groups. Each group was further divided into four subgroups. Group 1 was treated with TNF-? 0, 20, 40, 60ng/ml. Group 2 was treated with TNF-? 0, 20, 40, 60 ng/ml and Go6976 (4.6 nmol/ml). The apoptotic rate, protein kinase C alpha (PKC-?) expression and phosphorylation-PKC-? (p-PKC-?) were detected by flow cytometer and Western blotting respectively in 4 h, 8 h and 16 h. Result Treated with TNF-? (0, 20, 40, 60 ng/ml) for 4 h, the apoptotic rates of H22 cells were 2. 44% ? 0. 31 % , 1. 80% ? 0. 32% , 2. 73% ?0. 14% and 3. 05% ?0. 78% respectively, with no change on the expression of PKC-? and p-PKC-?; For 8 h, the expressions of PKC-? and p-PKC-? in H22 cells were up-regulated with increasing concentration of TNF-?; When PKC-? was inhibited with Go6976 at the same time, the apoptotic rates of cells increased significantly, being 2. 90% ?0.39%, 7.76% ?0.35%, 11.43% ?1.05% and 12.96% ?2.44% , respectively. Moreover, PKC-? and p-PKC-? were down-regulated accordingly. When H22 cells were treated with TNF-? only or combined with Go6976 for 16 h, the result was similar to that of 8 h; The apoptotic rate dropped in the group in which PKC-? was inhibited by Go6976 with TNF-? at 60 ng/ml, but the proportion of necrotic cells increased. Conclusion TNF-? up-regulates the expression of PKC-? and p-PKC-? in H22 cells. Inhibiting the activity of PKC-? significantly enhances the toxicity of TNF-? to H22 cells.