Effects of hyperthermia on multidrug-resistant human hepatocellular-carcinoma

The effects of hyperthermia (HT) on multidrug-resistant human hepatocellular carcinoma (HCC) were evaluated experimentally. This tumor, an AFP-producing human HCC, in which MDR1 mRNA and P-glycoprotein were overexpressed, was transplanted subsequently on nude mice. Ten days after the inoculation of the tumor into the rear section of the nude mice, either or both an intra-peritoneal injection of 8 mg/kg of adriamycin (ADR) was administered or hyperthermia (HT) was induced. HT was performed immediately by immersing the mice into a water bath at a temperature of 42-degrees-C for a period of 30 minutes. Hyperthermic therapy combined with ADR significantly inhibited the tumor growth compared with ADR or HT alone. Using ADR in combination with HT, the ADR concentration in the tumor remained at a significantly higher level for a prolonged period compared with ADR alone. The results indicate that HT enhanced the anti-tumor effect of chemotherapy even for multidrug-resistant HCC.