To increase the chemo-sensitivity of anaplastic thyroid carcinoma, we examined the effects of glycerol on the tumor growth after CDDP treatment. The cultured cells of an anaplastic thyroid carcinoma cell line (8305c) carrying a mutated p53 gene (mp53) were transplanted into the thighs of nude mice. Tumor growth was evaluated until 24 days after intraperitoneal injection of CDDP and/or pre-injection of glycerol to the tumor. We treated the mice with half the tumor volume of glycerol (1.2 M) and/or CDDP at 6 mg/kg (BW) either of which hardly inhibited tumor growth by itself. When we treated the mice with the combination of glycerol and CDDP at these concentrations, however, a clear delay of the tumor growth was observed. We also immunohistochemically analyzed the effects of glycerol on the induction of caspase-3 activity and apoptosis. Cells positive for cleavage to active caspase-3 and 85 kDa PARP, and apoptosis were hardly observed in the tumors when they were treated with glycerol or CDDP alone. In contrast, when they were treated with CDDP combined with glycerol, such positive cells were significantly increased. It has been shown that glycerol synergistically enhanced the effects of CDDP as a tumor suppressive agent through the induction of caspase-3-mediated apoptosis in 8305c tumors. Therefore, glycerol might be useful for chemotherapy in patients with mp53 cancer cells.

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