Enhancement of doxorubicin-induced cytotoxicity by hyperthermia in Ehrlich ascites cells.

Hyperthermia (HPT) at 43 degrees C for 30 min increased the cytotoxic activity of doxorubicin against the growth of Ehrlich ascites carcinoma cells. There was more delay in tumor growth with 89% inhibition in the tumor volume and 90% increase in the survival of the tumor-bearing animals compared to control group. Combination of HPT with doxorubicin showed a more pronounced inhibitory effect on tumor content of DNA, RNA, protein, cholesterol, total lipid and acid phosphatase activity. HPT did not significantly affect the doxorubicin uptake into tumor cells, but it has some inhibitory effect on some vital components. Along with other results, our data suggest the benefit of using HPT to enhance the cytotoxic activity of doxorubicin with a consequent reduction of doxorubicin dose and hence a decrease of its serious side effects.