Effect of epinephrine and combination treatment of epinephrine and heat onmelanoma cell lines. Study of cytotoxicity and kinetics of 72-kD stress protein

To elucidate the effect of epinephrine and the combination with heat on mal ignant cells, using two melanoma cell lines, HM6KO and G361, we have examin ed the cytotoxicity and induction of 72-kD stress protein (HSP72) alter the treatments. After epinephrine treatment, in both cell lines, cell survival rates decreased gradually in a concentration-dependent manner. After the c ombination treatment, cell survival rates decreased more than those when tw o treatments were done separately The cytotoxicity of epinephrine was more enhanced in G361 than in HM6KO by heat. After epinephrine treatment, in both cell lines, the level of HSP72 did not elevate. After combination treatment, in HM6KO. the level of HSP72 were hi gher than those of heat alone. In G361, the kinetics of HSP72 level was sim ilar to that of heat alone. These results suggest that epinephrine has a cytotoxicity to melanoma cells and the cytotoxicity is enhanced by the combination. In addition, it is pr obable that epinephrine does not have HSP72 inducibility in HM6KO and G361, and the different kinetics of HSP72 between the cell lines in the combinat ion treatment may play an important role to determine the degree of enhance ment.