Abstract: Objective To explore the effect of LncRNA BCYRN1 on the proliferation and motility of MCF-7 breast cancer cells and the growth of xenograft in mice by using short hairpin RNA (shRNA) interfering. Methods The expression level of BCYRN1 in breast cancer and para-cancerous tissues was detected by real-time quantitative PCR (RT-PCR). MCF-7 cells were divided into 3 groups, the blank control group (Control), the negative control group (shRNA-NC) and the interference group (sh-BCYRN1). The target fragments were transfected, their effect on expressions of the target genes were then verified by RT-PCR. The cell proliferation, invasion, migration ability and the expression levels of related proteins were detected by Edu, transwell assay, wound-healing assay and Western blotting, respectively. Vimentin level was detected by immunofluorescence method. The nude mice were given subcutaneous injection of MCF-7 cells to construct xenograft models. After tumor formation, nude mice were divided into two groups, the blank control group (negative control ) and the interference group ( sh-BCYRN1 ), and there were 20 cases in each group. The tumor weight and the expression levels of BCYRN1, Ki67 and N-cadherin in the transplanted tumors were detected 4 weeks later. Results The expression level of BCYRN1 was higher in breast cancer tissues than in para-cancerous tissues ( P < 0. 05). The percentage of Edu positive cells, the number of migrated and invasion cells, the positive rate of Vimentin, and the expression levels of Ki67 and N-cadherin were decreased in the interference group when compared with the blank control group ( P < 0. 05), while the expression level of E-cadherin was increased ( P < 0. 05). In the interference group, the expression level of BCYRN1 was decreased, and the tumor mass, the expression levels of Ki67 and N-cadherin were lower than those in the blank control group (P< 0. 05). Conclusion Interfering of LncRNA BCYRN1 can inhibit the proliferation and motility of MCF-7 breast cancer cells and the growth of xenograft.

Key words: long non-coding RNA, BCYRN1, MCF-7 breast cancer cell, cell proliferation, xenograft