The Role Of And Clinical Signature Of NEAT1 In Colorectal Cancer

Aims:Growing evidence suggests that the long non-coding RNA(lncRNAs)may mediate oncogenic or tumor suppressing effects in the development of tumor.LncRNAs may be a new class of tumor biomarkers and therapeutic targets.Therefore,this study aims to investigate the potential role of NEAT1 in predicting patients' clinical characteristics and progress in colorectal cancer,and probe the underlying mechanism of NEAT1 involving in the development of colorectal cancer.Methods: RT-qPCR was employed to evaluate the expression of NEAT1 in 30 colorectal cancer(CRC)tissues and matched normal tissues,another 70 CRC was performed to RT-qPCR for analyzing association of NEAT1 expression with the 100 patients' clinical characteristics and prognosis.Furthermore,knockdown or overexpression of NEAT1 was used to examine effect of NEAT1 on proliferation and invasiom in CRC cells,respectively.Then,we established nude mice xenograft model by subcutaneously injecting CRC cells,and testified the impact of NEAT1 on the tumor growth by stable overexpression NEAT1.What's more,we predicted the sites on NEAT1 and SIRT1 3'UTR which binds to miR-34 a by bioinformatics methods.And we cloned the SIRT1 3'UTR and NEAT1 downstream of a luciferase gene,and cotransfected these reporters with miR-34 a mimics in colorectal cancer cells.We detect NEAT1 affect cells proliferation and invasion through regaluting SIRT1 expression by co-transfected with pcDNA3.1-NEAT1 plasmid and si-SIRT1.Finally,we verify the correlation in NEAT1,miR-34 a and SIRT1 of 30 CRC tissues.Results: NEAT1 was dramatically increased in CRC tissues compared to normal tissues.The high expression of NEAT1 significantly positively correlated with the CEA level,lymphatic metastasis,liver metastasis and clinical stage(P = 0.003).We also found overall survival is poor in CRC patients with high expression of NEAT1.Ectopic expression of NEAT1 resulted in enhanced proliferation and invasiveness.Then,we generated xenograft models by impanting pcDNA3.1-NEAT1(stably overexpression NEAT1)cells into nude mices.As a result,overexpression of NEAT1 produced a marked increase in the rate of xenograft subcutaneous tumor growth.What's more,we predicted the sites on NEAT1 and SIRT1 3'UTR which binds to miR-34 a by bioinformatics methods.After constructing and transfecting clones,we confirmed the exact binding domain by which miR-34 a binds to NEAT1 and SIRT1 3'UTR through luciferase assay.We also found overexpression of NEAT1 completely abolished the effects of si-SIRT1 on cell proliferation and invasion in HT-29 and SW480 cells.What's more,the pro-SIRT1 effect of NEAT1 could be neutralized by miR-34 a in CRC cells,suggesting that NEAT1 confers miR-34a-dependent effects on SIRT1 expression.Finally,the expression level of miR-34 a negatively correlated with SIRT1 and NEAT1 RNA levels,and NEAT1 postively correlated with SIRT1,which strongly supported that miR-34 a negatively regulates SIRT1 and NEAT1 in CRC.Conclusion::NEAT1 could be considered as the initial factor that affects the development and progressing of colorectal cancer.NEAT1 regulates the proliferation and invasion of colorectal cancer,which partially depends on the activation of SIRT1,thus affecting the prognosis of colorectal cancer patients.