miR-300 inhibits epithelial to mesenchymal transition and metastasis by targeting Twist in human epithelial cancer

• Published in: Molecular cancer Vol. 13; no. 1; p. 121
• Main Authors: Yu, Jingshuang, Xie, Furong, Bao, Xin, Chen, Wantao, Xu, Qin
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 24.05.2014; BioMed Central
• Subjects: 3' Untranslated Regions; Analysis; Animals; Breast cancer; Breast Neoplasms - genetics; Breast Neoplasms - metabolism; Breast Neoplasms - pathology; Carcinoma, Squamous Cell - genetics; Carcinoma, Squamous Cell - metabolism; Carcinoma, Squamous Cell - pathology; Cell Line, Tumor; Epigenesis, Genetic; Epithelial Cells - metabolism; Epithelial Cells - pathology; Epithelial-Mesenchymal Transition - genetics; Female; Gene Expression Regulation, Neoplastic; Genes, Reporter; Genotype & phenotype; Head and Neck Neoplasms - genetics; Head and Neck Neoplasms - metabolism; Head and Neck Neoplasms - pathology; Humans; Luciferase; Luciferases - genetics; Luciferases - metabolism; Lung Neoplasms - genetics; Lung Neoplasms - metabolism; Lung Neoplasms - secondary; Medical research; Metastasis; Mice; Mice, Nude; MicroRNAs - antagonists & inhibitors; MicroRNAs - genetics; MicroRNAs - metabolism; Microscopy; Neoplasm Invasiveness; Nuclear Proteins - genetics; Nuclear Proteins - metabolism; Physiological aspects; RNA, Small Interfering - genetics; RNA, Small Interfering - metabolism; Signal Transduction; Twist-Related Protein 1 - genetics; Twist-Related Protein 1 - metabolism; Xenograft Model Antitumor Assays
• DOI: 10.1186/1476-4598-13-121
• ISSN: 1476-4598

Epithelial-to-mesenchymal transition (EMT) is a key step of the progression of tumor cell metastasis. Recent work has demonstrated some miRNAs play critical roles in EMT. In this study, we focused on the roles of miR-300 in regulating EMT. The expression levels of miR-300 were examined in epithelial carcinoma cells that underwent an EMT using quantitative reverse transcription-PCR. The role of miR-300 in EMT was investigated by transfection of the miR-300 mimic or inhibitor in natural epithelial-mesenchymal phenotype cell line pairs and in transforming growth factor (TGF) beta-induced EMT cell models. A luciferase reporter assay and a rescue experiment were conducted to confirm the target gene of miR-300. The efficacy of miR-300 against tumor invasion and metastasis was evaluated both in vitro and in vivo. Correlation analysis between miR-300 expression and the expression levels of its target gene, as well as tumor metastasis was performed in specimens from patients with head and neck squamous cell carcinoma (HNSCC). MiR-300 was found down-regulated in the HNSCC cells and breast cancer cells that underwent EMT. Ectopic expression of miR-300 effectively blocked TGF-beta-induced EMT and reversed the phenotype of EMT in HN-12 and MDA-MB-231 cells, but inhibition of miR-300 in the epithelial phenotype cells, HN-4 and MCF-7 cells, could induce EMT. The luciferase reporter assay and the rescue assay results showed that miR-300 directly targets the 3'UTR of Twist. Enforced miR-300 expression suppressed cell invasion in vitro and experimental metastasis in vivo. Clinically, miR-300 expression was found inversely correlated with Twist expression and reduced miR-300 was associated with metastasis in patient specimens. Down-regulation of miR-300 is required for EMT initiation and maintenance. MiR-300 may negatively regulate EMT by direct targeting Twist and therefore inhibit cancer cell invasion and metastasis, which implicates miR-300 as an attractive candidate for cancer therapy.