Study Of LncRNA MALAT1 On The Characteristics Of Proliferation And Apoptosis In Glioma Cells

Background Glioma in human brain is the most common intracranial malignant tumor,which has high morbidity,high recurrence,high mortality and poor prognosis.Although recent studies have made great progress in areas such as surgery,chemoradiotherapy and TTFields(Tumor Treating Fields,TTFields),the overall prognosis of glioma,especially glioblastoma(GBM),has not been notably improved.Therefore,Exploring and discovering the molecular mechanism of glioma cells occurrence and development,finding a new biological targeted therapy strategy are urgent to be solved at present,which are of crucial necessity and practical significance.lnc RNA(Long non-coding RNA,lnc RNA)can participate in the regulation of proliferation,apoptosis and other biological processes through a variety of pathways in glioma cells,and play important regulatory role in the occurrence and development of glioma,which can be used as a molecular orientation marker for the diagnosis,treatment and prognosis of glioma.lnc RNA MALAT1(Metastasis-associated lung adenocarcinoma,MALAT1)was firstly discovered in non-small cell lung tumors.It has been abnormally expressed in renal clear cell tumors,gallbladder cancer,pancreatic tumors,and participated in the regulation of biological behavior of malignant tumors in recent years.NF-κB signaling pathways can participate in biological progress such as inflammatory response,immune evasion,cell proliferation and differentiation,and then have an impact on human immunity and inflammatory response,regulation of cell cycle,and development of tumor cells.It may have some correlations between the activation of NF-κB signaling pathway and abnormal proliferation of glioma cells.However,the interaction between MALAT1 and NF-κB signaling pathways in glioma has rarely been reported.Objective(1)Bioinformatic analysis investigated the relationship between the expression of MALAT1 and the clinical prognosis of gliomas.Prognostic prediction model was constructed and evaluated to predict MALAT1 expression level and clinical prognosis.(2)Experiments with glioma cell lines investigated the effect of MALAT1 on the biological behaviors and explored the possible regulatory mechanism of MALAT1.Methods(1)Bioinformatic analysis explored the relationship between the expression level of MALAT1 and clinical prognosis.The predictors were selected by univariate and multivariate Cox proportional risk regression model.The clinical nomogram model was constructed based on the independent risk factors.The disfferentiation of the nomogram model was evaluated by AUC(Area Under the Curve)under the ROC(Receiver Operating Characteristic curve,ROC).The efficacy of the nomogram model was evaluated by calibration curve.(2)Lentivirus vector encoding anti-MALAT1 was firstly constructed and stably transfected into the U251 cells.RT-PCR detected the relative expression of MALAT1.(3)CCK-8 assay and flow cytometry detected proliferation and apoptosis,respectively.(4)Western blot assay detected the key protein including P65 and P50 in the NF-κB signaling pathway.Results(1)bioinformatical analysis demonstrated that glioma patients with high expression level of MALAT1 tended to be male,IDH mutant,primary status glioma and higher WHO grade(P(27)0.05).High expression of MALAT1 had significantly shorter OS compared with low expression of MALAT1(P(27)0.0001).Based on the results of univariate and multivariate Cox proportional hazard regression model,five predictors including expression of MALAT1,Age,WHO grade,PRS status,1p19 q co-deletion status were included in the nomogram predictive model.The AUC value of 1-year,3-year,and 5-year overall survival probability for nomogram were 0.851,0.892 and 0.908,respectively.ROC curves indicated that the nomogram had good discrimination ability.The calibration curves of 1-year,3-year,and5-year survival rates showed that the predicted values had good consistency with the actual values.(2)RT-PCR detected that the level of MALAT1 expression,MALAT1 was highest in U251 cell lines compared with NHA,U87,A172 and T98 G glioma cell lines(P(27)0.01).CCK-8 assay showed that knockdown of MALAT1 inhibited the cell proliferation ability of U251 cells(P(27)0.05).Western-blot assay showed that the protein of ki-67 in sh-MALAT1 expressed lower than sh-NC and Control(P(27)0.05).Flow cytometry showed that knockdown of MALAT1 inhibited the cell apoptosis ability of U251 cells(P(27)0.01).Knockdown of MALAT1 suppressed the expression of key protein P65 and P50 in the NF-κB signaling pathway(P(27)0.05).Conclusion(1)The expression level of MALAT1 was not only positively correlated with the WHO grade and negatively correlated with the clinical prognosis,but also an independent predictor for glioma patients.(2)The nomogram model constructed from above independent variables can be a useful supplement to predict the overall survival probability of glioma patients.(3)MALAT1 promoted the proliferation and inhabited apoptosis in U251 glioma cell lines via activating NF-κB signaling pathway.