Dual regulation by microRNA-200b-3p and microRNA-200b-5p in the inhibition of epithelial-to-mesenchymal transition in triple-negative breast cancer

Abstract

Epithelial to mesenchymal transition (EMT) involves loss of an epithelial phenotype and activation of a mesenchymal one. Enhanced expression of genes associated with a mesenchymal transition includes ZEB1/2, TWIST, and FOXC1. miRNAs are known regulators of gene expression and altered miRNA expression is known to enhance EMT in breast cancer. Here we demonstrate that the tumor suppressive miRNA family, miR-200, is not expressed in triple negative breast cancer (TNBC) cell lines and that miR-200b-3p over-expression represses EMT, which is evident through decreased migration and increased CDH1 expression. Despite the loss of migratory capacity following re-expression of miR-200b-3p, no subsequent loss of the conventional miR-200 family targets and EMT markers ZEB1/2 was observed. Next generation RNA-sequencing analysis showed that enhanced expression of pri-miR-200b lead to ectopic expression of both miR-200b-3p and miR-200b-5p with multiple isomiRs expressed for each of these miRNAs. Furthermore, miR-200b-5p was expressed in the receptor positive, epithelial breast cancer cell lines but not in the TNBC (mesenchymal) cell lines. In addition, a compensatory mechanism for miR-200b-3p/200b-5p targeting, where both miRNAs target the RHOGDI pathway leading to non-canonical repression of EMT, was demonstrated. Collectively, these data are the first to demonstrate dual targeting by miR-200b-3p and miR-200b-5p and a previously undescribed role for microRNA processing and strand expression in EMT and TNBC, the most aggressive breast cancer subtype.

The effects of chitosan/miR-200c nanoplexes on different stages of cancers in breast cancer cell lines

“…In the MDA-MB-435 cell line, the invasive cell number decreased to 15.2% in chitosan/miR200c group accordingly to untreated tumor group (p b 0.05). After the re-upregulation of miR-200c by using chitosan nanoplexes, the breast cancer cell invasion diminished according to our findings, which was similar to earlier data (Pecot et al, 2013;Rhodes et al, 2015). Ulhmann et al (2010) and Humphries and Yang (2015) reported the reducing effect of the miR-200c family on cancer cell intravasion.…”

“…2). This data showed a similarity with previous papers related to the downregulation of miR-200c in cancer cells (Deng et al, 2014;Rhodes et al, 2015). In this study, we tried to increase the miR-200c levels of the cells by transfecting the cancer cells with chitosan nanoplexes containing miR-200c to reach miR-200c level of the normal (healthy) cells (Fig.…”

“…The miRNAs in each cluster are likely to be co-regulated (Park et al, 2008). Several studies have shown that miR200s play a suppressive role in breast cancer development (Howe et al, 2011;Rhodes et al, 2015). The delivery of the miR-200 members into the tumor endothelium resulted in the marked reductions in metastasis and angiogenesis, and induced vascular normalization (Pecot et al, 2013).…”

MicroRNA‐335‐5p and ‐3p synergize to inhibit estrogen receptor alpha expression and promote tamoxifen resistance

“…To gain greater insight into the effects of the miR-335 transcript on estrogen signaling we performed qRT-PCR to determine basal expression levels of pre-miR-335, miR-335-5p, and miR-335-3p across a series of breast cancer cell lines (ERα + and ER − ). miR-335-3p was included in our analysis due to recent evidence suggesting a functional role for both strands of the miRNA duplex [22]. qRT-PCR results demonstrated that both miR-335-5p and miR-335-3p were robustly expressed across all breast cancer cell lines regardless of receptor status, with expression at physiologically relevant levels (Figure 1A).…”

Low miR200b-5p levels in minor salivary glands: a novel molecular marker predicting lymphoma development in patients with Sjögren’s syndrome

“…Despite the well-established role of the reduced miR200b-3p expression in EMT and associated oncogenesis, tumour metastasis and invasion,12–17 little are known for miR200b-5p, possibly because it represents the star strand, which is generally considered to degrade during miRNA biogenesis 24. Recently, it has been reported that miR200b-5p controls the non-canonical EMT in synergy with miR200b-3p by targeting PRKCA and PIP4K2A molecules in the RHOGDI pathway 25. Interestingly, miR200b miRNAs have been almost exclusively associated with solid tumours.…”