Combination studies with misonidazole and a cis-platinum complex: cytotoxicity and radiosensitization in vitro

cis-Dichlorodiammineplatinum(II) (cis-Pt(II) can act as a radiosensitizer of hypoxic mammalian cells in vitro. Used in combination with misonidazole the level of sensitization achieved is greater than that seen with either drug alone, and it is suggested that these compounds sensitize by independent mechanisms. For cells held at 37 degrees C, cis-Pt(II) shows much greater toxicity to hypoxic cells than to aerobic cells. In combination with misonidazole, no additional cytotoxic effect is shown towards aerobic cells than that seen for cis-Pt(II) alone. However, there is additional killing of hypoxic cells when they are treated with both drugs.