钙通道和Na+/H+交换在表皮生长因子促肝癌细胞生长中的作用

目的许多生长因子如表皮生长因子(EGF),与肿瘤的发生密切相关.EGF与表皮生长因子受体(EGFR)结合,通过一系列的信息传导,导致肝癌细胞的增生.但受体后的信息传导机制尚不清楚.本实验探讨酪氨酸激酶、蛋白激酶C、Na+/H+交换、钙调蛋白和电压依赖性钙通道在EGF促肝癌细胞生长中的作用.方法本研究于无血清RPMI1640中培养肝癌细胞SMMC7721,采用3H-Thymidine(3H-TdR)掺入的方法,检测肝癌细胞DNA合成速率,研究酪氨酸激酶、蛋白激酶C、Na+/H+交换、钙调蛋白和电压依赖性钙通道在EGF促肝癌细脆生长中的作用.结果EGF 10-9M对肝癌细脆的生长有极显著促进作用,与对照组比较差异有显著意义(P＜0.05),酪氮酸激酶阻滞剂Genistein对EGF的促肝癌细胞生长作用具有极显著抑制作用(P＜0.001).钙调蛋白阻滞剂W-7、蛋白激酶C阻滞剂H-7和Na+/H+交换阻滞剂amiloride对EGF的促肝癌细胞生长作用具有显著抑制作用(P＜0.001,P＜0.01,P＜0.05),而对基础状态细胞的3H-TdR掺入值无显著影响(P＞0.05).电压依赖性钙通道阻滞剂Varapamil对BGF的促肝癌细胞生长作用无显著抑制作用(P＞0.05),对基础状态细胞的3H-TdR掺入值亦无显著影响(P＞0.05).结论结果显示,酪氨酸激酶、蛋白激酶C、Na+/H+交换及依赖钙-钙调蛋白途径在BGF的作用中起关键作用.电压依赖性钙通道与EGF的作用无关.

Effect of Ca2+ channel and Na+/H+ exchange on the proliferation of hepatoma cells induced by epidermal growth factor

Objective To study the effect of tyrosine kinase,protein kinase C,Na +/H + exchange,calmodulin and voltage dependent Ca 2+ channel on the proliferation of hepatoma cells induced by EGF.Methods Hepatoma cell line SMMC7721 was cultured in RPMI1640 serum free medium.DNA synthesis rate of hepatoma cells was measured by the method of 3H TdR incorporation in order to study the effect of tyrosine kinase,protein kinase C,Na +/H + exchange,calmodulin and voltage dependent Ca 2+ channel on the proliferation of human heptoma cells induced by epidermal growh factor(EGF).Results EGF 10 -9 M stimulated the proliferation of heptoma cells significantly ( P <0 05),and this effect might be very significantly inhibited by tyrosine kinase inhibitor Genistein( P <0 01).Calmodulin inhibitor W 7,protein kinase C inhibitor H 7 and Na +/H + exchange inhibitor amiloride individually had very significant or significant depressing effect on the proliferation of hepatoma cells induced by EGF( P<0 001,P<0 01,P<0 05) ,but they all had no effect on the basic phase of cultured hepatoma cells ( P >0 05).Voltage dependent Ca 2+ channel inhibitor Varapamil had no inhibition on the proliferation of hepatoma cells induced by EGF( P >0 05),it also had no effect on the basic phace of cultured hepatoma cells( P >0 05).Conclusion Our data suggest that tyrosine kinase and Ca 2+ calmodulin dependent pathway,protein kinase C and Na +/H + exchange play a critical role on the proliferation of heptoma cells induced by EGF,and voltage dependent Ca 2+ channel is independent of the effect of EGF.