The Expression And Function Of Long Non-Codin RNA TUG1 In Laryngeal Squamous Cell Carcinoma

BackgroundLaryngeal carcinoma is one of the most common malignant tumors arising from the mucosa of larynx,accounting for 5.7%-7.6%of all malignance.The most pathologic type is laryngeal squamous cell carcinoma(LSCC).The ratio of morbidity in gender is 7-10:1.Recently,the morbidity of LSCC is rising year by year,especially in northeast and north of China.The pathogeny of LSCC is diverse,such as smoking,alcohol,human papilloma virus and laryngeal reflux.The laryngeal cancer can be classified into 3 clinical types according the primary location:supraglottic carcinoma,glottic carcinoma and subglottic carcinoma.They have different symptoms with the development of tumor,including hoarseness,throat pain,and dyspnea.The treatment of the LSCC includes primary surgery with pre-or postoperative radiotherapy and primary radiotherapy with chemotherapy.Although the treatment of the LSCC has been improved in recent years,the prognosis is still far from satisfactory.Therefore,it is of vital importance to identify specific carcinogenesis-associated biomarkers for early-stage diagnosis and potential targets for therapy.Long noncoding RNAs(LncRNAs),which comprise longer than 200 nucleotides and lack protein-coding ability,are well recognized as important regulators of processes such as gene expression and chromosome modification.Moreover,an increasing number of LncRNAs are closely associated with the pathogenesis of cancers,such as breast cancer,lung cancer,pancreatic cancer,hepatocellular carcinoma,and leukemia.LncRNA taurine-upregulated gene 1(TUG1),a 7.1-kb gene located at chr22q12.2,was first identified in a microarray and found that its transcript was upregulated in taurine-treated retinal cells in mice.Recent studies revealed that TUG1 was involved in the development of a variety of cancers,including some squamous cell carcinomas.However,the role of TUG 1 in the pathogenesis of LSCC has yet to be explored.In our study,we first detected the expression of TUG1 in 64 pairs of LSCC and corresponding adjacent nontumor tissue specimens,and found its expression was closely linked to clinicopathological characteristics of LSCC patients.Further,we identified the role of TUG 1 in the regulation of LSCC by In vitro experiments.PART ?The expression and the clinical significance of the LncRNA TUG1 in laryngeal carcinomaObjectiveTo study the expression of LncRNA TUG1 in laryngeal carcinoma and its relation with the clinicopathologic characteristics.MethodQuantitative real-time PCR was performed to investigate the relative expression in the LSCC tissues in comparison to adjacent non-tumor tissues in 64 patients.Standard statistical analysis was used to analyse the relation between the expression level of the LncRNA TUG1 and clinicopathologic characteristics of the LSCC.ResultsThe relative expression level of TUG1 in LSCC tissues was 1.4528 ± 0.6592,while it was 0.9999 ±0.5505 in contrast with adjacent normal tissues(P<0.05).The higher expression levels of TUG 1 were significantly correlated with advanced T category(P=0.025),worse lymphoid node metastasis(P = 0.014)and late clinical stage(P =0.003).However,no significant correlation was observed between TUG1 expression and other clinicopathological features,such as age,gender,smoking,alchol,differentiation and tumor location.ConclusionTUG1 was highly expressed in the LSCC and the level of expression was associated with the T classification,clinical staging and lymph node metastasis.The smoke and wine hobby,the age and gender of the patients,and the location and differentiation of tumor were not significantly associated with the expression of the TUG1.The TUG1 may have promoted the development of LSCC.Part ?The influence of LncRNA TUG1 expression on laryngeal carcinoma cells.ObjectiveTo investigate the influence of LncRNA TUG1 expression on the proliferation,migration and invasion of LSCC cells.MethordsHep-2 cells were transfected with a mixture of TUG 1-targeted small interfering RNA(siTUG1)and the efficiency of silencing TUG1 was subsequently quantified by RT-qPCR.3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide(MTT)was used to measure the effect of TUG1 on cell proliferation.Transwell assay and flow cytometry were employed to determine the effect of TUG 1 on cel1 migration and invasion.Western-blot were performed to explore the relation of TUG1 and p53 in LSCC.Results:The expression levels of TUG 1 were significantly decreased in Hep-2 cells transfected with TUG1-siRNA in comparison with the scrambled sequence.MTT assay demonstrated that depletion of TUG1 in Hep-2 cells markedly inhibited their proliferation.Transwell assays suggested that TUG1 could enhance the invasive and migratory ability of LSCC cells.Cell-cycle analysis revealed that,siTUG1 reduced the number of cells in S phase.With the western blot,TUG1 knockdown obviously increased the expression of p53 mRNA and protein.Conclusion:Silencing of TUG 1 markedly inhibited proliferation,cell-cycle progression,migration,and invasion of LSCC cells,whereas depletion of TUG1 led to increased apoptosis.TUG1 might partly function by negatively regulating the expression of p53.