Tiam1, negatively regulated by miR-22, miR-183 and miR-31, is involved in migration, invasion and viability of ovarian cancer cells.

Tiam1 has been implicated in the invasive phenotype of various carcinomas. However, its role in ovarian cancer remains to be elucidated, including its upstream regulatory mechanisms. In the present study, we examined the differential expression of Tiam1 in 10 normal ovarian tissues and 17 paired primary and corresponding metastatic ovarian cancer tissues by semi-quantitative immunohistochemistry. It was found that Tiam1 expression was remarkably increased in both primary and metastatic ovarian cancer tissues relative to normal ovarian tissues. Loss-of-function study revealed that downregulation of Tiam1 in SKOV-3ip and HO-8910PM cells lead to reduced cell migration and invasion, and growth inhibition without significantly affecting cell apoptosis. Subsequent regulatory study further confirmed the negative regulatory effects of miR-22, miR-183 and miR-31 on Tiam1 expression. Taken together, our data suggested that Tiam1 may be involved in the aggressive behavior of ovarian cancer, and differential expression profiles of microRNA (miRNA) may contribute to the dysregulation of Tiam1 abundance, which contributes to the invasive, migratory and viability properties of ovarian cancer cells.