| Objective:Glioma is the most common malignant tumor in human central nervous system, which consisted of 50% of all intracranial tumors, and is the toughest one to treat. Despite considerable developments of neurosurgery, radiotherapy and chemotherapy, the prognosis is still not good. Nowadays, oncologists were attracted by tons of new conceptions of malignant tumor treatment, among all of them, the conception of drug induced tumor cell differentiation and apoptosis, which differed from the conventional therapies, gained overall attention. Preliminary studies revealed that Sodium phenylbutyrate (SPB), among other new differentiation inducing drugs, exerted better differentiation inducing effects. In this study, we will investigate the effects of SPB on proliferation inhibition and apoptosis induction of the rat C6 glioma cells by different kinds of experiments.Methods:Rat C6 glioma cells in exponential phase of growth were collected and grouped into control group and 1,2,4mmol/L SPB group respectively. The cells in 1, 2,4mmol/L SPB group were cultivated in 1,2,4mmol/L SPB accordingly, and cells in the control group were treated without SPB, for 2-7days before the experiments were conducted. The morphological difference between the control and experimental groups were detected by light microscope; and the ultra-structure differences were detected by transmission electron microscope; cell proliferation was detected by the MTT assay, and the cell growth curve was draw according to it; cell circle was analyzed by flow cytometry; cell apoptosis was detected by TUNEL assay; cell clone formation rate was determined by the soft agar clone forming test; and the expression of GFAP was measured by western blot.Results:The morphological observation under light microscope showed that:in experimental groups, the cells turned to be long and thin spindle shape, and the number of the cysto-process increased, the nuclear-cytoplasmic ratio decreased, in the 2,4mmol/L SPB group, the observation showed the enlargement and lengthen of the cysto-process, and the tumor cells turned to be multiplicity, the most significant morphological change emerged in the 4mmol/L SPB group; the ultra-structure observation under electric microscope of the rat C6 glioma cells being induced by SPB showed that the nuclear-cytoplasmic ratio decreased and the number of the organelles increased, such as mitochondrial and rough endoplasmic reticulum, in the cells of the experimental groups, the apoptotic body was found in the 4mmol/L SPB group; the MTT assay and the cell growth curve showed the cell proliferation was inhabited by SPB in a dosage depended manner(P<0.05); the flow cytometry analysis showed that, after being induced by SPB, the number of the cells stayed in G0/G1 phage increased(P<0.01), while the number in S phage decreased(P<0.01), and cell apoptosis increased in the high SPB dosage group (P<0.01); the TUNEL assay showed the cell apoptosis increased in the experimental groups; the cloning formation rate detection revealed that:the colonies in the control groups emerged earlier and were larger than those experimental ones, and the cloning formation rate was higher (35.5%), while almost no effective cell colony were emerged in SPB treated groups(P<0.01); the western blot analysis showed that the GFAP expression in the experimental groups increased (P<0.05).Conclusion:SPB can apparently inhibit the proliferation of rat G6 glioma cells in vitro, and can induce cell differentiation, even apoptosis in high dosage. This study provides the experimental evidence for clinical usage of SPB in treating glioma patient.
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