Abstract: Objective  To investigate the mechanism of HOST2 lncRNA targeting miR-211 in ovarian cancer cell metastasis.
  Methods  Quantitative real-time polymerase chain reaction(qRT-PCR) was used to detect the expression of HOST2 lncRNA and miR-211 in seven kinds of ovarian cancer cells. Dual luciferase reporter gene assay was used to detecte the targeted correlation between of miR-211 and HOST2 lncRNA. The candidate cells were divided into 3 groups: the negative control group, the HOST2 lncRNA overexpression group and both HOST2 lncRNA and miR-211 overexpression group. Cell scratch assay, transwell invasion and migration assays and nude mice xenograft tumor assays were conducted to assess the effects of HOST2 lncRNA and miR-211 on cell metastasis capabilities in vivo and in vitro after transfection. Western Blot was used to detect the expression changes of metastasis-associated proteins in ovarian cancer cells.
  Results  HOST2 lncRNA was highly expressed in seven ovarian cancer cells while miR-211 was significantly down-regulated in these cells. And there was a significant negative correlation between HOST2 lncRNA and miR-211. Dual luciferase reporter assay showed that the luciferase activity of SKOV3 cells was significantly inhibited in the SKOV3 cells after co-transfection of the HOST2-WT with miR-211 mimic. Overexpression of HOST2 lncRNA promoted cell scratch healing, invasion and migration in vitro and metastasis of peritoneal xenografts in vivo. In turn, co-transfection of miR-211 mimic reversed this phenomenon. Western Blot results showed that overexpression of HOST2 lncRNA significantly increased the expression of SOX4, Snail1 and N-cadherin proteins and decreased the expression of E-cadherin protein, whereas co-transfection of miR-211 mimic reversed the expression of the proteins above.
  Conclusion  HOST2 lncRNA may promote the metastasis of ovarian cancer cells in vivo and in vitro by competitively binding to miR-211 as competing endogenous RNAs.

Key words: ovarian neoplasms；HOST2 lncRNA, miR-211