| BackgroundGliomas are the most common primary brain tumors.Rich blood supply and strong aggressiveness lead to high recurrence rate,mortality and poor prognosis,Therefore,understanding molecular mechanisms controlling the aggressive phenotypes of malignant gliomas may reveal novel targets for disease intervention.The pathogenesis of glioma has not yet been fully understood.In recent years,more and more researches showed that abnormally expressed lncRNAs are closely related to the development and progression of glioma.Therefore,in this study,we selected lncRNA BACH1-AS1 and CDKN2B-AS1 as target molecules based on previous microarray results and related literatures review.Objective To investigate the expression profiles of lncRNAs in glioma and adjacent normal brain tissues and target the key lncRNA as the object for further study.To study the relationship between the expression of BACH 1-AS1 and CDKN2B-AS1 and the clinicopathological parameters and prognosis of glioma patients.To explore the biological function and molecular mechanisms of BACH 1-AS1 and CDKN2B-AS1 in the development and progression of gliomas in order to find new drug target for clinical anti-glioma therapy.Methods Four pairs of malignant glioma tissue samples and adjacent normal brain tissue samples of the four glioma patients were collected.We used the Agilent Human lncRNA microarray system to detect the different expression profiles in lncRNAs between the two groups.The BACH 1-AS1 and CDKN2B-AS1 expression were measured by qRT-PCR,and compared between human glioma and adjacent normal brain tissues.The correlations between BACH1-AS1 or CDKN2B-AS1 level and multiple clinical parameters and patient survival were analyzed.The effects of either knockdown(transfected with si-BACH1-AS1 or si-CDKN2B-AS1)or overexpressing(transfected with letivirus)BACH 1-AS1 or CDKN2B-AS1 on the viability(by MTT assay)and invasion(by Transwell assay)of glioma cells,and also on RAS,TGF-?/SMAD signaling components and p15,p21(by Western blot)were examined.In addition,the RAS signaling inhibitor FTS(Farnesyl Thiosalicylic Acid)was used to treat BACH 1-AS1 overexpressing glioma cell lines.And the recombinant human TGF-?1 was used to treat CDKN2B-AS1 overexpressing glioma cell lines.Lastly,in vivo effect of targeting BACH 1-AS1 or CDKN2B-AS1 on xenograft growth was evaluated.Results The microarray results showed that the expression of BACH 1-AS 1 was significantly up-regulated in glioma tissues.The qRT-PCR results showed BACH1-AS1 and CDKN2B-AS1 were significantly up-regulated in glioma tissues,and correlated with advanced pathological grading or shortened overall survival.Si-BACH1-AS1 or si-CDKN2B-AS1 dramatically reduced viability and invasion,while overexpressing BACH 1-AS1 or CDKN2B-AS1 enhanced both phenotypes of glioma cells.Mechanistically,BACH 1-AS1 promoted the expressions of RAS,p-Raf-1,p-AKT and p-ERK.Treating BACH1-AS1-overexpressing glioma cells with FTS partially yet significantly reduced cell viability and invasion.Meanwhile,CDKN2B-AS1 suppressed the expressions of p-SMAD2,p-SMAD3,p15 and p21.Treating CDKN2B-AS1-overexpressing glioma cells with recombinant TGF-?1 partially yet significantly reduced cell viability and invasion.In vivo,after knockdown of BACH1-AS1 or CDKN2B-AS1,the subcutaneous tumorigenicity of nude mice was significantly decreased.Concomitantly,the expression levels of RAS,p-Raf-1,p-AKT,and p-ERK in sh-BACH1-AS1 tumor tissues were significantly decreased.And the protein levels of TGF-?1,p15,p21,p-SMAD2 and p-SMAD3 were significantly higher in all sh-CDKN2B-AS 1 xenografts than in sh-NC xenografts.Histological analysis showed that sh-BACH1-AS1 and sh-CDKN2B-AS1 xenografts were associated with reduced Ki-67 expression than sh-NC xenografts.Conclusion The expression levels of lncRNA BACH 1-AS1 and CDKN2B-AS1 in glioma tissues were significantly higher than that in adjacent normal brain tissues.BACH1-AS1 promotes the malignant phenotypes of glioma cells through activating RAS signaling in vitro and in vivo.And CDKN2B-AS1 promotes the malignant phenotypes of glioma cells by inhibiting TGF-?/SMAD signaling,p15 and p21 in vitro and in vivo.Not only BACH1-AS1 and CDKN2B-AS1 may serve as predictive biomarker for the survival of glioma patients but targeting BACH1-AS1 and CDKN2B-AS1 may benefit the treatment of glioma. |
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