In Vitro And In Vivo Inhibitory Effect Of Resveratrol On Rat Glioblastoma Cells And Its Relevance With Altered STAT3 Signaling

Background:Gliomas, also known as neuroglioma, is the most common primary central nervous system tumors, accounting for about 50% of primary intracranial tumors. Malignant gliomas generally refers Ⅳ astrocytoma, namely glioblastoma that is the most common malignant brain tumor, in which median survival time after diagnosis is generally 12 months. Means of conventional treatment of surgery, radiotherapy and chemotherapy in terms of improving the quality of life of patients or prolong the survival time of patients are unable to achieve the desired results, the reasons: First, the tumor growth rapidly, and second, most of the drugs can not pass through the blood-brain barrier or will not achieve therapeutic effect. In recent years, resveratrol, which is concerned because of its low toxicity, being through the blood-brain barrier, inhibiting tunour of growth and other characteristics as a Plant extract, however, STAT3 in cancer research process has also attracted the attention of scholars, and it has been reported that a catalytic role in glioma growth, proliferation and other processes. People discovered greatly functions of STAT3 signaling pathway and some potential therapeutic targets associated with STAT3 when they explored the mechanisms of resveratrol treating cancers from a biological point of view, our previous studies had shown that resveratrol inhibited glioma cells, and found that the expression of STAT3 in cells before and after treatment was different.In view of the above collection and collation of relevant information, our group made resveratrol treatment with RG2 rat glioblastoma cell lines in vitro and established rat tumor model by different routes of administration of resveratrol treatment in vivo. Then we detected STAT3 signal transduction pathway and its negative regulation of protein expression to explore the effects of resveratrol on rat glioblastoma molecular mechanisms.Objective: 1) to detect the impact of resveratrol on RG2 rat glioblastoma cells; 2) to establish SD rat glioma model; 3) to detect the tumor-bearing rat treated with resveratrol in different treatment; 4) to compare cells and tissues in the case of STAT3 signal transduction pathway; 5) to detect P-SHP2, SOCS3, PIAS3 three negative regulation in cells and tissues protein expression; 6) to analyse the molecular mechanisms of tumor suppressor with resveratrol in tumor cells and tumor tissues.Methods: RG2 rat glioblastoma cells were cultured in 10% fetal bovine serum, 1% Penicillin- streptomycin, 89% low glucose DMEM, made cell seeding,then the group of treatment was cultured in 100μM resveratrol at steady growth state. We collected the control group, the treatment group cells and the cell seeding after 48 h. Normal cultured RG2 cells grew in SD rat brain localization were divided into normal group, tumor group, lumbar puncture treatment group, original location treatment group, embedding treatment group, we gave treatment to the last three groups every other day until tumours were growing in the models, and brain samples were collected after natural death. We detected apoptosis by TUNEL, the protein expression by immunocytochemistry/ immunohistochemistry, qualitative detection of protein expression by Western Blotting, transcription of genes by RT-PCR. At last, we analysed the changes in the indicators and their interaction or affection before and after treatment.Results: 1) The apoptosis in the group of cells treated with resveratrol was significantly, and the group of SD rat brain tissues with various routes of administration treated with resveratrol show us avarying degrees of apoptosis; 2) the expression of STAT3 protein in the group of cells treated with resveratrol decreased significantly, and the groups of SD rat brain tissues with various routes of administration treated with resveratrol all showed a downward trend; 3) the mRNA levels of STAT3 remained unchanged both in cells and tissues with or without resveratrol; 4) cells in treatment group showed an upward trend in the negative regulation of protein, while the trend of the groups of SD rat brain tissues with various routes of administration treated with resveratrol were upward in IHC, but downward in Western Blotting, considering whether there was degradation of normal brain tissue or tissue protein contamination.Conclusions: 1) resveratrol can induce apoptosis in RG2 cells and rat glioma tissues; 2) resveratrol can inhibit STAT3 protein levels in glioma cells and tissues but not mRNA levels; 3) resveratrol can inhibit the expression of STAT3 by up-regulation P-SHP2, SOCS3, PIAS3 three negative regulatory protein expression levels in RG2 cells, but there are differences in vivo; 4) resveratrol reflected its potential value in the treatment of glioblastoma both in vitro and in vivo experiments, and lumbar puncture treatment more effective than original location treatment and embedding treatment.