Effect of calmodulin and voltage-dependent Ca2+ channel on the proliferation of heptoma cells induced by epidermal growth factor

The effect of thyrosine kinase, calmodulin and voltage-dependent Ca 2+ channel on the proliferation of hepatoma cells induced by EGF was studied. Hepatoma cell line SMMC7721 was cultured in RPMI1640 serum-free medium. DNA synthesis rate of hepatoma cells was measured byH-TdR incorporation. 10-9 mol/L EGF could significantly stimulate the proliferation of hepatoma cells (P 0.05), but it had very significantly inhibitory effect on the proliferation of hepatoma cells induced by EGF (P2+ channel inhibitor Varapamil had no inhibition on the proliferation of hepatoma cells induced by EGF (P>0.05). It had no effect on the basic phase of cultured hepatoma cells (P>0.05). It is suggested that tyrosine kinase and Ca2+- calmodulin-dependent pathway may play a critical role on the proliferation of heptoma cells induced by EGF, and voltage-dependent Ca2+ channel is independent of the effect of EGF.