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 upstreamregulatory mechanisms. In the present study, we examined the differential expressionof Tiam1 in 10 normal ovarian tissues and 17 paired primary and correspondingmetastatic ovarian cancer tissues by semi-quantitative immunohistochemistry. Itwas found that Tiam1 expression was remarkably increased in both primary and metastaticovarian cancer tissues relative to normal ovarian tissues. Loss-of-function studyrevealed that downregulation of Tiam1 in SKOV-3ip and HO-8910PM cells lead toreduced cell migration and invasion, and growth inhibition without significantlyaffecting cell apoptosis. Subsequent regulatory study further confirmed the negativeregulatory 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 ovariancancer, and differential expression profiles of microRNA (miRNA) may contributeto the dysregulation of Tiam1 abundance, which contributes to the invasive, migratoryand viability properties of ovarian cancer cells.