Expression And Mechanism Of LncRNA SNHG20 In Esophageal Squamous Cell Carcinoma

Background and Objective Esophageal cancer is the eighth most common malignant tumor in the world.In our country,the incidence of esophageal cancer in men has jumped to the third place,second to lung cancer and stomach cancer,and its incidence rate ranks fifth among women;esophageal cancer mortality ranks fourth among men and women.The main esophageal pathology of our country is squamous cell carcinoma.Studies have shown that SNHG20(Small nucleolar RNA host gene 20)is highly expressed in many malignant tumors such as hepatocellular carcinoma,breast cancer and cervical cancer and is associated with tumor progression.However,the SNHG20 expression in the esophagus squamous cell carcinoma and its possible mechanisms have not been reported.This study first explored the expression of SNHG20 in esophageal squamous cell carcinoma,the correlation between the expression of SNHG20 and clinical variables,and its relationship with prognosis.Then,to further investigate the possible biological mechanism of SNHG20 in esophageal squamous cell carcinoma in vitro study of esophageal squamous carcinoma cells.Methods 1.Detection of expression of SNHG20 in esophageal squamous cell carcinoma tissues and cells by q RT-PCR.2.We use the 80 clinical cases with complete data to study the correlation between the expression of SNHG20 and clinical variables and prognosis.3.Transfection of a specific designed plasmid vector to silence the expression of SNHG20,and study the effect of SNHG20 on proliferation and apoptosis of esophageal squamous carcinoma cells.4.Study on migration and invasion of esophageal squamous carcinoma cells by transwell assays.And to determine whether SNHG20 promotes metastasis of esophageal squamous cell carcinoma by detecting the expression of E-cadherin,Ncadherin,Vimentin,and ZEB1.5.Rescuing trials to investigate whether SHHG20 promotes proliferation and metastasis of esophageal squamous carcinoma cells by modulating the ATM-JAK-PDL1 signaling pathway.Results 1.The expression of SNHG20 tested by q RT-PCR is upregulated in ESCC tissue(n=80)compared with adjacent nontumor tissues(n=80).All the four ESCC cell lines exhibit higher levels of SNHG20 in contrast to Het-1A cells,among which SNHG20 expression in KYSE450 cells is the highest.2.The level of SNHG20 in patients with ESCC is closely associated with tumor size(P=0.007),lymph node metastasis(P=0.007),TNM stage(P=0.001),and tumor(P=0.014).The results of Cox regression analysis reveal that only the level of SNHG20 and TNM stage could serve as the independent prognostic markers for ESCC patients.Kaplan-Meier curve suggests that higher SNHG20 expression in ESCC patients is strongly correlated with poorer overall survival.3.SNHG20 is apparently inhibited in KYSE450 cells and markedly overexpressed in Het-1A cells.MTT assays demonstrate that cell viability is strikingly impaired in sh SNHG20 transfected KYSE450 cells but significantly enhanced in pc DNA3.1/SNHG20 transfected Het-1A cells.Consistently,SNHG20 knockdown represses the colony forming ability of KYSE450 cells while SNHG20 overexpression increases that of Het-1A cells.Furthermore,cell apoptosis rate is notably increased in KYSE450 cells under SNHG20 silence but significantly decreased in Het-1A cells upon SNHG20 upregulation.4.SNHG20 silence leads to evident repression on cell migration and invasive capacity of KYSE450 cells,whereas SNHG20 overexpression exhibits improved migratory and invasive ability in Het-1A cells.Knockdown of SNHG20 greatly elevates the expression of epithelial marker E-cadherin expression while evidently decreases the expression of the mesenchymal markers N-cadherin and Vimentin as well as that of ZEB1.On contrary,SNHG20 overexpression leads to reduced E-cadherin expression and strengthened levels of N-cadherin,Vimentin and ZEB1.5.The levels of p-ATM,p-JAK1/2 and PD-L1 are downregulated in KYSE450 cells under SNHG20 inhibition but upregulated in Het-1A cells after pc DNA3.1/SNHG20 transfection.Moreover,ectopic expression of ATM reverses the repressed capacities of cell migration and invasion caused by SNHG20 inhibition.Furthermore,ATM upregulation causes remarkable lowered E-cadherin expression but enhanced level of ZEB1,N-cadherin and Vimentin in SNHG20 suppressed KYSE450 cells.Conclusions 1.SNHG20 might act as an oncogene in ESCC progression,implying a novel biomarker for the prognosis of ESCC patients.2.SNHG20 affects the biological processes in ESCC through the ATM-JAK-PD-L1 pathway,and SNHG20 can be a novel effective target for ESCC treatment.