Abstract 509: MicroRNA-140 suppresses the migration and invasion of colorectal cancer cell possibly through targeting Smad3
Authors: Song Bo , Zhao Wenyue , Li Lianhong 
Published: August 2015

Abstract
Objective To investigate the roles of microRNA-140 (miR-140) on the migrating and invasive potentials of colorectal cancer (CRC) cell and the possible mechanism. Methods miR-140 mimics (miR-140), miR-140 specific inhibitor (Anti-miR-140) or siRNA against Smad3 (Smad3 siRNA) were transfected into human CRC cell line RKO respectively using Oligofectamine or Lipofectamine2000. Quantitative Real-time PCR (qRT-PCR) was used to measure the expression levels of miR-140 and Smad3 mRNA. Smad3 protein was analyzed by Western blot. The in vitro cell migrating and invasive potentials were determined by Wound-healing and Transwell chamber assays after up-regulating or down-regulating miR-140 or knocking down Smad3. Results The protein levels of Smad3 were significantly reduced after up-regulating miR-140 when compared to Control or Negative Control (NC) using Western blot. The results of qRT-PCR indicated that no significant difference was found in the levels of Smad3 mRNA between miR-140 transfection and NC (1.11±0.13 vs 1.00±0.06, P&gt;0.05). Wound-healing assay showed that the migrating potential was dramatically attenuated by miR-140 compared to Control and NC, whereas no significance was found when compared to Smad3 siRNA transfecting cells. The cells migrating through Transwell chamber without matrigel in miR-140 group were 76.2±4.4, remarkably lowered than that in the Control (267.1±4.9) and NC (336.1±5.7), P values were all less than 0.05. There was no significant difference between miR-140 and Smad3 siRNA (83.5±7.3) groups. Transwell chamber with matrigel assay demonstrated that cells penetrating through the membrane were 109.5±7.4 in miR-140 group, dramatically lowered than that in the Control (403.1±5.1) and NC (392.6±8.4), P values were all less than 0.05. Smad3 siRNA transfection had the similar effect. Down-regulation of miR-140 increased the protein level of smad3, and partially reversed the inhibition of miR-140 on the potentials of cell migration and invasion. Co-transfection of miR-140 inhibitor and Smad3 siRNA had no significant effect on the Smad3 protein expression and the capacities of cell migration and invasion. Conclusions miR-140 directly targets Smad3 in the post-transcriptional level. miR-140 suppresses the migrating and invasive potentials of CRC cell, possibly through down-regulating Smad3. The findings of this study suggest that miR-140 may have a unique potential as a possible biomarker candidate for tumor metastasis diagnosis and therapy.
[Keywords] Colon neoplasms; microRNA-140; SMAD family member 3; Cell migration; Cell invasion
Citation Format: Bo Song, Wenyue Zhao, Lianhong Li. MicroRNA-140 suppresses the migration and invasion of colorectal cancer cell possibly through targeting Smad3. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 509. doi:10.1158/1538-7445.AM2015-509