| Background:Glioma is the most common central nervous system malignancies. Complete surgical resection is difficult. Its rapid growth and short postoperative recurrence interval, leads to the poor prognosis. The average survival time of high-grade gliomas is still about a year. Advances in genetics and molecular biology biological reveals that the development of glioma is also a complex biological process which involves abnormal expression of many genes. Therefore actively exploring the molecular mechanisms for the development of glioma has important clinical therapy significance. Studies have confirmed that RACK1gene plays a key role in regulating cell growth, differentiation, malignancy, metastasis, invasion, etc. But how RACK1gene regulates the neuroepithelial tissue. The relationship between RACK1and glioma genesis and development, and how RACK1regulates glioma biology and behavior are still unknown. These problems in domestic and abroad have not been a systematic study and reported. We speculate that RACK1gene may be involved in the development and progression of gliomas and plays an important regulatory role, RACK1gene may will be a new target prospect for the treatment of glioma, and may provide a reference for clinical diagnostic and genetic diagnosis.Objective:The expression levels of RACK1in glioma tissues were determined and judged the relationship of pathological grades. Then by transient and stable RNA interference in human glioma cell lines the effects as well as involved molecular mechanism of RACK1downregulation on proliferation, apoptosis and invasion. A preliminary analysis of its role molecular mechanism, combined with clinical and pathological preliminary evaluation of its clinical application have been shown.Methods:Real-Time PCR and Western-Blot were used to detect the expression levels of RACK1mRNA and protein on the collection of45cases at all levels of clinical gliomas,10normal brain tissues and U87-MG, CHG-5cell lines. The result was confirmed RACK1overexpressed in human gliomas. Then downregulate the cellular level transient gene expression RACK1by siRNA instantaneous interference and observed RACK1gene on biological characteristics of cell lines U87-MG, CHG-5, etc.(proliferation, invasion, apoptosis, etc). Then through lentivirus stably transfected U87-MG cells in vivo tests to established the animal models in vivo regulation of RACK1confirmed the proliferation of glioma. The mechanisms for the development of its regulatory glioma were last preliminary study, combined with clinical data to evaluate the potential value of RACK1gene for diagnosis and treatment of human brain gliomas.Result:Real-time PCR and Western-Blot results showed that showed that low-grade gliomas RACK1expression were significantly different (P <0.05) higher than the normal brain tissue, statistically significant high-grade glioma and normal brain tissue is more significant (P<0.01), low-level and high-level also statistically significant (P<0.05)。The expression of RACK1showed an increasing tendency with the malignancy of glioma. RACK1expression was also upregulated in U87and CHG-5cells compared to normal brain tissues (P<0.01). MTT assay demonstrated that in RACK1downregulated U87and CHG-5cells, the cell proliferation rate was lower when compared with controls (P<0.05). In RACK1downregulated U87and CHG-5cells, the cell apoptosis rate was much higher when compared with controls (P<0.01). RACK1 downregualted cells showed decreased invasion ability when compared with controls (P<0.01). The average tumor weight in the RACK1-specific shRNA group was remarkably lower than that in the control group and NC group. After RACK1siRNA interference, the expression of Bcl-2whether U87-MG or CHG-5were significantly decreased, the expression of Bax were significantly increased, Bcl-2/Bax ratio also decreased significantly(P<0.01). SiRNA reduced the expression of the Src/Akt phosphorylation, both in the two cell lines were significantly downregulated. RACK1may also confirmed that the size of gliomas, blood supply, involving the site with a certain correlation (P<0.05).Conclusion:1.RACK1were highly expressed in glioma;2.RACK1in vitro and in vivo tests can positively regulate the proliferation of glioma invasion and anti-apoptosis;3.RACK1played a role possibly through Bcl-2/Bax, Src/AKt related signaling pathways. |
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