Geneome-wide Screening And Function Analysis Of Long Noncoding RNAs In Bladder Urothelial Cell Carcinoma

Objective To identify the aberrantly expressed lnc RNAs and m RNAs that may play an important role in contributing to bladder cancer pathogenesis though high throughput microarrays; validate the expressions of the screened lnc RNA(termed lnc RNA-n336928) and its neighbor oncogene SPP1 in a large size of samples; evaluate the correlation between lnc RNA-n336928 expression level and clinicopathological variables and prognosis; investigate the functions and mechanisms of lnc RNA-n336928 in bladder cancer progression.Methods Differentially expressed lnc RNAs and m RNAs between bladder cancer tissues and paired adjacent non-cancerous tissues were identified by microarray(n=3). Subsequent q RT-PCR validation was conducted using tissue samples from 95 patients with bladder cancer. The correlation between lnc RNA-n336928 expression level and clinicopathological variables were evaluated by Chi-square test. Kaplan-Meier analysis and Cox proportional hazards regression models were used to investigate the correlation between lnc RNA-n336928 expression and prognosis of bladder cancer patients. The effects of lnc RNA-n336928 was assessed by kncokdown or overexpression the lnc RNA in bladder cancer cell lines. The function of bladder cancer cell proliferation was assessed by CCK-8 and Brdu assay. The migration and invasion of bladder cancer cells were investigated by wound healing assay and transwell assay. Total RNAs and proteins were colleted after transfection, further q RT-PCR and western blot were used to analysis the expression level of SPP1 m RNA and protein.Results A series of lncRNAs and mRNAs were differentially expressed in bladder cancer tissues in microarray screen. The expression level of lnc RNA-n336928 and SPP1 m RNA were significantly higher in bladder cancer tissues compared to that in adjacent noncancerous tissues(P<0.001). Chi-square test showed that expression of lnc RNA-n336928 and SPP1 m RNA were positively correlated with bladder tumor stage and histological grade(P<0.001). Kaplan-Meier survival analysis revealed that patients with bladder cancer with high expression of lnc RNA-n336928 had shorter overall survival time compared to patients with low expression of lnc RNA-n336928.Multivariate analysis indicated that lnc RNA-n336928 was an independent prognostic factor for overall survival for bladder cancer patients. Functional analysis demonstrated that lnc RNA-n336928 has no effect on bladder cancer cell proliferation. Wound healing assay and transwell assay showed that abnormal expression of lnc RNA-n336928 may take part in regulation of migration and invasion of bladder cancer cells. The expressions of SPP1 m RNA and proteins were upregulated or downregulated after lnc RNA-n336928 overexpressed or knockdown.Conclusion Our study shows that lnc RNAs play an impotant role in the development of bladder cancer. Lnc RNA-n336928 is upregulated in bladder cancer tissues. Lnc RNA-n336928 may play important roles in bladder cancer metastasis through regulation of oncogene SPP1. Lnc RNA-n336928 can be used as a potential prognostic and therapeutic target for bladder cancer.