Synergy Effects Research On Combination Of Cisplatin With Microwave Hyperthermia Induce Human Hepatocellular Carcinoma Cell Line BEL-7404 Apoptosis

Background:Liver cancer is the sixth most common cancer worldwide in terms of numbers of cases (626,000 or 5.7% of new cancer cases), but the number of deaths is almost the same (598,000),55% of cases are in China alone, the diagnosis and treatment of liver cancer in China is extremely critical. The current treatment includes surgical resection,liver transplantation,minimally invasive treatment,biological treatment,radiotherapy and chemotherapy, etc. Because of the very poor prognosis, 5-year survival rate is still less than 5%. Hyperthermia is use of a variety of heat to the body's temperature to increase the effective treatment temperature range and maintain a certain period of time, selectively killing of cancer cells, controlling the transfer of cancer cells in a wide range through thermal effects and the biological effects of secondary. Current study shows that: hyperthermia can induce apoptosis of tumor cells with chemotherapy has synergistic anti-tumor effect,but the specific mechanism of molecular biology research has not yet been completely understood. Direct biological target of thermal effect may be the cell membrane and the organelle. Mitochondria of eukaryotic cells as an important organelle, the change of its structure and function has relation with apoptosis closely: In the stimulated of pro-apoptotic factor, mitochondrial membrane permeability transition pore (MPTP) opening, mitochondrial transmembrane potential reduction or loss, the pro-apoptotic protein released from the mitochondrial matrix, induce of apoptosis.Objective:This experiment aims to investigate whether exposure of human hepatocellular carcinoma cells line BEL-7404 to microwave hyperthermia will induce apoptosis effects;exposure of human hepatocellular carcinoma cells line BEL-7404 to cisplatin combined with microwave hyperthermia will induce synergistic effects and the relations with mitochondrial transmembrane potential.Methods : Establishing the human hepatocellular carcinoma cells line BEL-7404 culture model in vitro, Flow cytometric analyses were used for detecting the control group,Cisplatin alone group,(40℃-43℃,2h) microwave hyperthermia group and cisplatin with (40℃-43℃,2h) microwave hyperthermia group in human hepatocellular carcinoma BEL-7404 cells apoptosis rates and mitochondrial transmembrane potential changes. Cell apoptosis were detected by AnnexinⅤ-FITC/PI Apoptosis Detection Kit; mitochondrial transmembrane potential was detected by MitocaptureTM Mitochondrial Apoptosis Detection Kit.Results: 42℃microwave hyperthermia can induce human hepatocellular carcinoma cell line BEL-7404 apoptosis in vitro, at the same time accompanied by a decline in mitochondrial transmembrane potential, With the temperature to 43℃, a further increase in apoptosis and mitochondrial transmembrane potential drop. Cisplatin with 42℃microwave hyperthermia group compared to cisplatin alone group or microwave hyperthermia alone group, it can induce more apoptosis rates and mitochondrial transmembrane potential loss. Hyperthermia has synergistic anti-tumor effect with chemotherapy. With the temperature to 43℃, a further increase in apoptosis and mitochondrial transmembrane potential drop, the synergistic anti-tumor effect with chemotherapy was more pronounced.Conclusions:(42℃-43℃,2h) microwave hyperthermia can induce apoptosis of human hepatocellular carcinoma cell line BEL-7404; (42℃-43℃,2h)microwave hyperthermia can reduce the level of mitochondrial transmembrane potential; (42℃-43℃,2h)microwave hyperthermia has synergistic anti-tumor effect with cisplatin; mitochondrial transmembrane potential changes may be one of the mechanisms of apoptosis induced by (42℃-43℃,2h) microwave hyperthermia and synergistic killing effect induced by (42℃-43℃,2h) microwave hyperthermia with cisplatin.