[Combination effects of CDDP and hyperthermia in mouse bladder tumor (MBT-2)]

The combination effects of CDDP and hyperthermia in mouse bladder tumor (MBT-2) were investigated both in vivo and in vitro. MBT-2 was transplanted into the hind leg of a C3H/He mouse. Then the leg was dipped in a hot water bath immediately after the intraperitoneal administration of CDDP. The antitumor effects were evaluated from tumor volume. The CDDP plus hyperthermia (43 degrees C) group showed remarkable tumor growth retardation. The in vitro colony forming assay showed that MBT-2 cultured cells treated with CDDP at 42 degrees C exhibited great colony forming inhibition in comparison with the CDDP alone cells. The effects of CDDP plus hyperthermia on the cell cycle progression of MBT-2 cultured cells were studied by using flow cytometry. The results showed that the cells treated with CDDP at 42 degrees C exhibited an accumulation of cells in the C2 phase for many hours as compared with the CDDP alone cells, indicating thermal enhancement of DNA damage in MBT-2 cultured cells treated with CDDP.