| Aims: Hyperthermia is under investigation as a important treatment for tumor. Due to insufficient blood perfusion, resulted in hypoxia and low PH, tumor cells, especially solid tumors, are more sensitive to mild hyperthermia than normal tissue cells. In addition, chemotherapy, immunotherapy and radiotherapy combined with hyperthermia may produce synergistic anticancer effects. Recently, it was reported that the tumoricidal effects of hyperthermia can be attributed, in part, to apoptosis. Apoptosis may be enhanced by hyperthermia not only in some normal mammalian tissues but also in tumors such as mastcytoma. Nitric oxide(NO) is a multi-faced molecule with double regulatory roles in many areas of biology, moreover, NO is closely related with carcinogenesis, progression and metastasis of tumor. On the one hand, NO can induce apoptosis in tumor cells as effector molecule of macrophage, on the other hand, NO accelerates tumor growth by angiogenesis and increasing blood flow. The complexity of its biological effects can be does-dependent and cell-type specific. Understanding the roles of NO in carcinogenesis will provide important clues for the treatment of tumor by NO-modulating drugs. To date, however, little is known about that the therapeutic effects of hyperhtermia combined with Nitric Oxide donor (Isosorbide dinitrate, ISDN) for tumor and its mechanism. The aim of this experiment is to elucidate the synergistic effects of hyperthermia and ISDN on murine hepatocarcinoma and induction apoptosis in Hep-A cells.Materials and Methods: In vivo, Hep-A tumor cells were injected to right foot pat of NIH mice to establish tumor-bearing animal model. Mice werecontinuously given ISDN (100 mg/kg) and/or hyperthermia treatment(43掳C X 25min), while mice treated with nature saline were used as control. Concentrations of NO in urine, tumor size and regional nodes metastasis were measured at 7d, 14d after therapy.In vitro, Hep-A tumor cells were routine cultured in RPMI-1640 culture medium containing 10% FCS, lOOU/ml penicillin and lOOU/ml streptomycin at 37 掳C in a humidified atmosphere of 5% CO2- The Hep-A cells in this study were incubated with 0.1 mg/ml ISDN(the final concentration), Heating was carried out in a water bath at 43 掳C, which is used clinically on the human body, for 25 min and the control group was given only culture medium. The growth, migration and adhesion abilities of tumor cells were assayed by microculture tetrzoalium assay(MTT). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe ultrastructural changes of cells, and flow cytometry was performed to detect the apoptotic ratio, while the levels of Bcl-2 were examined with Western blot assay.Results: In vivo, compared with hyperthermia or ISDN alone, the tumor volume of hyperthermia and ISDN group was obviously smaller (p < 0. 05) . Metastatic rates of hyperthermia and ISDN group was significantly lower than control (p < 0. 01) . Concentrations of NO in the urine in ISDN group ,hyperthermia combination with ISDN group were higher than those in hyperthermia group and control (p< 0. 05) .In vitro, stronger inhibitive effects were observed on abilities of growth, migration and adhesion in three experimental groups than that of control, and hyperthermia combined with ISDN group had better inhibitory effect than other groups (p < 0. 05) . With electron microscopy, great changes of cell apoptosis were observed, including microvilli disappearance or reduction, cell shrinkage, chromatin condensation or margination and the presence of "apoptosis bodies". A few apoptotic cells were detected when Hep-A cells were incubated with hyperthermia or ISDN alone, whereas, a great deal of apoptotic cells were observed in tumor cells treated with combination treatment. The apoptotic ratio induced by hyperthermia and ISDN group was higher than other groups, furthermore, the levels of Bcl-2 werelow-regulated in three experimental groups.Conclusion It was suggested that the combination therapy using hyper...
|
PDF Full Text Request