Expression And Significance Of Beclbt-1、mTOR In The Human Glioma

Background and ObjectiveIn the tumor of the central nervous system，human glioma is the most commonprimary brain tumor that is derived from the neural epithelium，accounting for about35.26％~60.96％of all intracranial tumors，which has the biological characteristics ofthe rich blood supply and invasive proliferation，and the tumors were almost in theway of invasive growth，which is not easy to cut all by operation and is poortreatment，and it has the clinical characteristics of high recurrence rate，highmortality，high morbidity and the low rate of cure. The current treatment is still acomprehensive treatment by the primary of surgical treatment combined withradiotherapy and chemotherapy，though its diagnostic and treatment standards hasmade great progress in areas such as surgical treatment，radiation therapy andchemotherapy， the prognosis of patients with these tumors remains poor. Thedevelopment and treatment of human gliomas occurred for neurosurgery is still thefocus of research and related fields. With the latest advances in the cancer research ofmolecular biology，cancer targeted therapy has been an important subject in the areaof cancer research. Therefore，the search for new therapeutic targets in human gliomabecome is always the point of the current gene therapy. Autophagy is a evolutionary conserved change in the subcellular level，which iscaused by autophagy and release of free fatty acids through lysosomal degradation ofcytoplasmic organelles in the cell to update，adapt to the environment and maintainhomeostasis.During the course of changes in autophagic dynamic，autophagy signaland transport pathways，the negative control of autophagy is closely related to thebechance and development of all kinds of tumors，and abnormal expression ofautophagy genes can promote or inhibit the formation of certain tumors. Autophagygene Beclin-1is associated with a candidate tumor suppressor gene found in tenyears， through the promotion of autophagy and apoptosis to inhibit tumordevelopment，and Beclin-1gene abnormal expression is found in a variety of tumors.Beclin-1gene is mainly through Ⅲ type PI3K ((phosphatidylinositol3-kinase) toform a complex regulation of other ATG autophagic protein and locate in theprecursor structure to regulate autophagy activity. mTOR (mammalian target proteinof rapamycin) is a target protein of mammal rapamycin. It has been recognizedrecently that it plays an important role in the growth，proliferation and survivalprocesses of the cell， such as nerve muscle regeneration，insulin signaling and theformation of a variety of tumors. It is considered currently that Beclin-1mediatedautophagy/apoptosis interaction and feedback mechanisms and mTOR mediatedautophagy/proliferation interaction and feedback mechanisms have become animportant way in the regulation mechanism regulating autophagy to promote cellsurvival， and we could guess that it has formed a regulation of autophagy interactionnetwork by Beclin-1and mTOR node targeting. Beclin-1and mTOR in humanglioma research is relatively small in the related research at home and abroad. Thechief objective of the research will disclose the expression of autophagy-related geneBeclin-1and mTOR in human gliomas，and the relationship of pathological gradegliomas and theirs correlation，and to analyse further the role of both the occurrenceand development of human glioma，which may be a new idea in clinical diagnosisand treatment.Materials and methods43cases of surgical Glioma specimens taken from the department ofneurosurgery of the second affiliated hospital of Zhengzhou University from Jul， 2012to Aug，2013，and all cases are of intact datas and invaded for the first time.None was treated by radiotherapy，chemotherapy or immunotherapy，23males and20females included，from6to69years old，mean39.72±18.24years old. As theexperimental group，the43cases of glioma tissues were graded by the year2007WHO pathological grade Standard(The Details is shown in Table2.1)，all sectionswere selected and systematized as22cases of low-level group (grade Ⅰ2cases of，gradeⅡ20cases)，21cases of high-level group (12cases of grade Ⅲ，9cases ofgrade Ⅳ).The non-tumor brain tissues serving as control group were obtained from11patients requiring surgical decompression due to brain injury or cerebralhemorrhage in the same period. The study used RT-PCR and immunohistochemistrySP method to detect the expression of the gene Beclin-1and mTOR in43cases and11cases of non-glioma brain tumor，the processing of all datum were analysed by SPSS17.0software，Two Independent-Samples t Test was used to compare two groups ofquantitative data，comparing multiple sets of quantitative data applied One-WayANOVA，and the LSD-t test was used for pairwise comparisons. Comparisons of twosample rate were applied by Chi-square statistics，and paired χ2test was used for theDifference Analysis；Pearson correlation test was used for the Correlation Analysis.Avalue of α=0.05was considered as the statistically significant test standards.Results1.The mRNA and protein expression of Beclin-1The Beclin-1mRNA expression in the brain non-tumor tissue group，gliomagroup，low grade group， high grade group is successively0.901±0.115，0.626±0.077，0.754±0.087，0.448±0.053，by Two Independent-Samples t Test，it showsthat there was a significant statistical significance between non-tumor brain tissuesand glioma tissue（st=10.853，p＜0.05），and by one-way ANOVA，LSD-t test showsthat there were significant statistical significance between any two of non-tumor braintissue、low grade group and high grade group（F=92.445，p＜0.05）；The proteinexpression rate of Beclin-1in the non-tumor brain tissue group，glioma group，lowgrade group，high grade group is respectively100.0%，51.2%，68.2%and38.1%.Byχ2test from tables，it shows that non-tumor brain tissue and glioma group（χ2=6.856，p＜0.05），low grade group and high grade group （χ2=3.909，p＜0.05）were significant statistical significance.2.The mRNA and protein expression of mTORThe mRNA expression of mTOR in the non-tumor brain tissue group， gliomagroup，low grade group，high grade group is successively0.206±0.035、0.575±0.063、0.413±0.052、0.654±0.075，by Two Independent-Samples t Test，it shows that therewas a significant statistical significance between non-tumor brain tissues and gliomatissues（t=-17.112，p＜0.05），and by one-way ANOVA，LSD-t test shows that therewere significant statistical significance between any two of non-tumor brain tissue、low grade group and high grade group（F=103.419，p＜0.05）；The protein expressionrate of Beclin-1in the non-tumor brain tissue group，glioma group，low grade group，high grade group is respectively18.2%、69.8%、54.5%and85.7%.By χ2test fromtables，it shows that non-tumor brain tissue and glioma group（χ2=7.636，p＜0.05），low grade group and high grade group （χ2=4.949，p＜0.05）were significantstatistical significance.3.The correlation between the expression of Beclin-1gene and mTOR gene ingliomaVia Pearson correlation test，it analyses that the Beclin-1and mTOR mRNAexpression between in human glioma tissue and obtains the correlation coefficient r=-0.838，p <0.05（there is a statistically significant difference）. By paired χ2test， itanalyses the expression of protein between Beclin-1and mTOR in human gliomatissue and obtains the correlation coefficient r，=-0.648，p <0.05（there is also astatistically significant difference）.By quantitative and qualitative analysis results itshows a negative correlation between the expression of two genes.Conclusion1.The mRNA and protein expression of Beclin-1in non-tumor brain tissue ishigh，and as the pathologic grade of human glioma increases，the expression levelsgradually decrease.2. The mRNA and protein expression of mTOR in non-tumor brain tissue is low，and as the pathologic grade of human glioma increases，it also increases in theexpression levels gradually.3. There is a negative correlation between the expression of Beclin-1and mTOR， and it implied that the expression of Beclin-1degradation may promote tumordevelopment by the mTOR-mediated signaling pathway.