The Effect And Mechanism Of LncRNA SNHG5 On The Proliferation Of Breast Cancer

Background:Breast cancer is the most common cancer among women.Long non-coding RNAs(lnc RNAs)have been proved to play an important role in breast cancer,but the specific mechanism is still poorly understood.Increasing evidence shows that many lnc RNA transcripts can play the function of competitive endogenous RNAs(ce RNAs)by competitively binding micro RNA(mi RNA).Small nucleolar RNA host gene 5(SNHG5)was a member of the lnc RNA.It was first mentioned in the study of B-cell lymphoma.SNHG5 is also considered as a potential carcinogen for the development and progression of various cancers,including colorectal cancer,gastric cancer and hepatocellular carcinoma.However,the role and mechanism of SNHG5 in breast cancer have not been elucidated.Objectives:This study aims to reveal the specific mechanism of SNHG5 in the occurrence and development of breast cancer,provide new strategies for the treatment of breast cancer,and provide new prognostic indicators for breast cancer.Methods:1.Ues MTT,plate clone formation test,Ed U test and cell apoptosis analysis to conform SNHG5 expression between MDA-MB-231-si SNHG5 and control cells,determine SNHG5 effects on cell proliferation in vitro.2.The same methods to conform SNHG5 expression between T47D-SNHG5 and control cells in vitro.Use Xenograft to determine the effect of SNHG5 on cell proliferation in vivo.3.Use cell synchronization and flow cytometry analysis to confirm the cell cycle between MDA-MB-231-si SNHG5 and control cells.The expression levels of Cyclin B1 and D1 were detected by western blot.4.The interaction between mi R-154-5p and SNHG5 was determined by dual-luciferase and RIP techniques.The expression of mi R-154-5p in test cells were detected by RT-q PCR.The interaction between SNHG5 and mi R-154-5p were detected by MTT,plate cloning and Ed U techniques.5.Use prediction software and luciferase to ensure the target gene of mi R-154-5p.And use RT-q PCR to identify the interactin between them.6.Use RT-q PCR,xenograft and so on to clarify the relationship between SNHG5 and PCNA and the mechanism of promoting proliferation in breast cancer.7.Use RT-q PCR and km-plotter to clarify the relationship between SNHG5 and clinical prognosis of breast cancer patients.Research results:1.In vitro,knockdown of SNHG5 can inhibit the proliferation of breast cancer cells and promote apoptosis.2.In vitro and vivo,up-regulation of SNHG5 expression can promote the proliferation of breast cancer cells.3.In terms of cell cycle,overexpression of SNHG5 can promote the cell cycle from G1 phase to S phase.4.SNHG5 acts as a sponge for mi R-154-5p to promote the proliferation of BC.5.PCNA is a direct target of mi R-154-5p.6.SNHG5 promotes the proliferation of breast cancer cells by regulating PCNA.7.SNHG5 predicts poor prognosis and inversely correlates with mi R-154-5p in clinical samples.Conclusions:In this study,SNHG5 showed the activity of promoting breast cancer proliferation both in vivo and in vitro.The depletion of SNHG5 significantly resulted in cell cycle arrest at G1 phase.As a recruiting "sponge" of mir-154-5p,SNHG5 reduces the inhibitory effect of mir-154-5p on proliferating cell nuclear antigen(PCNA).SNHG5 promotes the proliferation and cell cycle progression of breast cancer cells by up-regulating the expression of PCNA.In summary,our data revealed the SNHG5-mi R-154-5p-PCNA axis and provided a new mechanism to explain breast cancer proliferation.