Targeting of RhoE inhibits epithelial-mesenchymal transition during colorectal cancer cell migration

Objective Despite microRNA(miR-200b) being proved to promote the proliferation of colorectal cancer(CRC) cells, the relationship between mi R-200 b and epithelial-mesenchymal transition(EMT) of CRC cells remains poorly understood. The aim of the study was to investigate the relationship between miR-200 b and EMT during CRC cell migration.Methods The effect of miR-200 b on EMT-associated markers E-cadherin and vimentin was evaluated by western blot in CRC cells(SW620 and HT-29) by treatment with mi R-200 b mimics and inhibitors. A luciferase reporter assay was employed to detect downstream targets of mi R-200 b. Transwell migration assays were used to detect CRC cell migration. Results Western blots revealed that treatment with miR-200 b mimics led to up-regulation of E-cadherin and down-regulation of vimentin, metalloproteinase(MMP)-9, and MMP-2, whereas treatment with mi R-200 b inhibitor exhibited opposite effects on expression of E-cadherin and vimentin. Luciferase reporter assays demonstrated that Rho E(RND3) was targeted by miR-200 b. Two predicted target sites of miR-200 b were present in the 3'-UTR of Rho E. Predicted target site 1 was from nucleotides 1584 to 1591, and site 2 was from nucleotides 1729 to 1735. Rho E knockdown cell lines were also established to investigate the impact of Rho E and mi R-200 b on EMT and cell migration. Rho E knockdown enhanced the effect of miR-200 b mimics, up-regulating E-cadherin and down-regulating vimentin. Rho E knockdown also inhibited cell migration. Furthermore, miR-200 b mimic treatment further promoted the inhibitory effect of Rho E knockdown on cell migration. Conclusion miR-200 b inhibited EMT and CRC cell migration partly via inhibiting Rho E expression in CRC. Rho E and miR-200 b might therefore be promising target genes in the management of CRC.

Objective Despite microRNA （miR-200b） being proved to promote the proliferation of colorectal cancer （CRC） cells, the relationship between miR-200b and epithelial-mesenchymal transition （EMT） of CRC cells remains poorly understood. The aim of the study was to investigate the relationship between miR-200b and EMT during CRC cell migration. Methods The effect of miR-200b on EMT-associated markers E-cadherin and vimentin was evaluated by western blot in CRC cells （SW620 and HT-29） by treatment with miR-200b mimics and inhibitors. A lucifer- ase reporter assay was employed to detect downstream targets of miR-200b. Transwell migration assays were used to detect CRC cell migration. Results Westem blots revealed that treatment with miR-200b mimics led to up-regulation of E-cadherin and down-regulation of vimentin, metalloproteinase （MMP）-9, and MMP-2, whereas treatment with miR- 200b inhibitor exhibited opposite effects on expression of E-cadherin and vimentin. Luciferase reporter assays demonstrated that RhoE （RND3） was targeted by miR-200b. Two predicted target sites of miR-200b were present in the 3＇-UTR of RhoE. Predicted target site 1 was from nucleotides 1584 to 1591, and site 2 was from nucleotides 1729 to 1735. RhoE knockdown cell lines were also established to investigate the impact of RhoE and miR-200b on EMT and cell migration. RhoE knockdown enhanced the effect of miR- 200b mimics, up-regulating E-cadherin and down-regulating vimentin. RhoE knockdown also inhibited cell migration. Furthermore, miR-200b mimic treatment further promoted the inhibitory effect of RhoE knock- down on cell migration.