Dynamics and plasticity of the epithelial to mesenchymal transition induced by miR-200 family inhibition

Abstract

Whereas miR-200 family is known to be involved in the epithelial-to-mesenchymal transition (EMT), a crucial biological process observed in normal and pathological contexts, it has been largely unclear how far the functional levels of these tiny RNAs alone can propagate the molecular events to accomplish this process within several days. By developing a potent inhibitor of miR-200 family members (TuD-141/200c), the expression of which is strictly regulatable by the Tet (tetracycline)-On system, we found using a human colorectal cell line, HCT116, that several direct gene target mRNAs (Zeb1/Zeb2, ESRP1, FN1and FHOD1) of miR-200 family were elevated with distinct kinetics. Prompt induction of the transcriptional suppressors, Zeb1/Zeb2 in turn reduced the expression levels of miR-200c/-141 locus, EpCAM, ESRP1 and E-Cad. The loss of ESRP1 subsequently switched the splicing isoforms of CD44 and p120 catenin mRNAs to mesenchymal type. Importantly, within 9 days after the release from the inhibition of miR-200 family, all of the expression changes in the 14 genes observed in this study returned to their original levels in the epithelial cells. This suggests that the inherent epithelial plasticity is supported by a weak retention of key regulatory gene expression in either the epithelial or mesenchymal states through epigenetic regulation.

The miR‐200b–ZEB1 circuit regulates diverse stemness of human hepatocellular carcinoma

“…C). Taken together, these findings were consistent with previous reports of EMT suppression by miR‐200b …”

“…It has been reported that iR‐200 family members inhibit EMT via downregulation of ZEB1/2 . We firstly determined the relative expression level of miR‐200b in seven HCC cell lines by quantitative RT‐PCR.…”

“…It has been reported that iR-200 family members inhibit EMT via downregulation of ZEB1/2. 36,37 We firstly determined the relative expression level of miR-200b in seven HCC cell lines by quantitative RT-PCR. As compared with the average expression level of 14 nontumor liver tissue samples, all HCC cell lines had decreased miR-200b expression ( Fig.…”

“…Taken together, these findings were consistent with previous reports of EMT suppression by miR-200b. [25][26][27]36,38 Since the downregulation of miR-200b occurred in the early stage of HCC, we examined the role of miR-200b in the initiation of HCC. We found that ectopic expression of miR-200b in HepG2 and Tong cells suppressed both anchorage-independent growth in soft agars ( Fig.…”

Metformin Inhibits Tumorigenesis and Tumor Growth of Breast Cancer Cells by Upregulating miR-200c but Downregulating AKT2 Expression

“…The miR-200 family of miRNAs consists of five members grouped in two independent transcriptional clusters: miR-200a, -200b, and -429, located on chromosome 1p36, and miR-200c and -141, located on 12p13 18 . MiR-200c is the predominant member of the miR-200 family, which suppresses the epithelial-mesenchymal transition (EMT), and the downregulation of miR-200 family members in some tumors promotes invasion and metastasis 19 - 21 . Song and colleagues found that miR-200c inhibits breast cancer proliferation by targeting KRAS 22 .…”