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Background/Aims: Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype. Our study investigated the functional role of miR-212-5p in TNBC. Methods: Realtime PCR was used to quantify miR-212-5p expression levels in 30 paired TNBC samples and adjacent normal tissues. Wound healing and Transwell assays were used to evaluate the effects of miR-212-5p expression on the invasiveness of TNBC cells. Luciferase reporter and Western blot assays were used to verify whether the mRNA encoding Prrx2 is a major target of miR-212-5p. Results: MiR-212-5p was downregulated in TNBC, and its expression levels were related to tumor size, lymph node status and vascular invasion in breast cancer. We also observed that the miR-212-5p expression level was significantly correlated with a better prognosis in TNBC. Ectopic expression of miR-212-5p induced upregulation of E-cadherin expression and downregulation of vimentin expression. The expression of miR212-5p also suppressed the migration and invasion capacity of mesenchymal-like cancer cells accompanied by a morphological shift towards the epithelial phenotype. Moreover, our study observed that miR-212-5p overexpression significantly suppressed Prrx2 by targeting its 3’-untranslated region (3’-UTR) region, and Prrx2 overexpression partially abrogated miR-212-5p-mediated suppression. Conclusions: Our study demonstrated that miR-212-5p inhibits TNBC from acquiring the EMT phenotype by downregulating Prrx2, thereby inhibiting cell migration and invasion during cancer progression. [ABSTRACT FROM AUTHOR]

Previous work has demonstrated that the expression of microRNA-21 (miR-21) is implicated in cervical cancer (CC). However, little is known regarding its associations with clinical parameters. We first conducted a meta-analysis using data from Gene Expression Omnibus (GEO) microarrays and The Cancer Genome Atlas (TCGA). Then, enrichment analysis and hub gene screening were performed by bioinformatic methods. Finally, the role of the screened target genes in CC was explored. According to the meta-analysis, the expression of miR-21 in cancer tissues was higher than in adjacent nontumor tissues (P < 0.05). In addition, 46 genes were predicted as potential targets of miR-21. After enrichment analyses, it was detected that these genes were enriched in various cancer pathways, including the phosphatidylinositol signaling system and mammalian target of rapamycin (mTOR) signaling pathway. In this study, bioinformatic tools and meta-analysis validated that miR-21 may function as a highly sensitive and specific marker for the diagnosis of CC, which may provide a novel approach to the diagnosis and treatment of CC. [ABSTRACT FROM AUTHOR]

Many studies have revealed that microRNAs (miRNAs) play crucial roles in cancer development and progression. miRNA-30a (miR-30a), as a member of the miR-30 family, has been implicated in various cancers. However, the role of miR-30a in osteosarcoma remains unclear. In the current study, we found that miR-30a was significantly downregulated in osteosarcoma tissues and cell lines by using quantitative real-time polymerase chain reaction (qRT-PCR). In addition, miR-30a could inhibit cancer cell growth, migration, and invasion in vitro. Furthermore, bioinformatics of miRNA target prediction and luciferase reporter assay indicated that MEF2D is a direct target of miR-30a. miR-30a was able to reduce the mRNA and protein expression of MEF2D as assessed using RT-PCR and Western blotting assay. Interestingly, overexpression of MEF2D partially reversed the miR-30a-reduced cell proliferation, migration, and invasion of osteosarcoma cell, indicating that miR-30a suppresses osteosarcoma cell proliferation and metastasis partially mediated by inhibition of MEF2D. Overall, our study demonstrated that miR-30a functions as a tumor suppressor by targeting MEF2D in osteosarcoma, providing a promising prognostic biomarker and a therapeutic strategy for osteosarcoma. [ABSTRACT FROM AUTHOR]