title: miRNA-21 promotes proliferation and invasion of triple-negative breast cancer cells through targeting PTEN.
abstract: MicroRNAs (miRNAs) are small single-stranded RNAs that bind to the 3'UTR of the mRNAs of target genes. They can target multiple genes and regulate translation or degradation of the mRNA. miRNAs target genes in a tissue-specific manner, and the role of a particular miRNA varies according to tumor origin or even subtype within the same cancer. This study evaluated the effect of miR-21 expression in triple-negative breast cancer (TNBC) tissues and MDA-MB-468, a cell line derived from TNBC tissues. miR-21 was consistently upregulated in TNBC and MDA-MB-468 cells compared to normal tissues. Inhibition of miR-21 by miR-21 antisense oligonucleotides decreased the proliferation, viability, and invasiveness of MDA-MB-468 cells and enhanced apoptosis. Furthermore, we confirmed that PTEN was downregulated by miR-21 in MDA-MB-468 cells. The results indicated that PTEN may mediate the oncogenic properties of miR-21 in TNBC. In summary, miR-21 was upregulated in TNBC tissues and cells, and promoted the proliferation and invasion of MDA-MB-468 cells, but negatively regulated the expression of PTEN protein. Inhibition of miR-21 or overexpression of PTEN protein could be promising strategies for the treatment of patients with TNBC.
authors.affiliation: Breast and Thyroid Surgery Ward III, The Affiliated Zhongshan Hospital of Dalian University Dalian 116001, Liaoning Province, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Fang
authors.affiliation: Breast and Thyroid Surgery Ward III, The Affiliated Zhongshan Hospital of Dalian University Dalian 116001, Liaoning Province, China.
authors.forename: Jiping
authors.initials: J
authors.lastname: Xie
authors.affiliation: Breast and Thyroid Surgery Ward III, The Affiliated Zhongshan Hospital of Dalian University Dalian 116001, Liaoning Province, China.
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Breast and Thyroid Surgery Ward III, The Affiliated Zhongshan Hospital of Dalian University Dalian 116001, Liaoning Province, China.
authors.forename: Ziwei
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: Breast and Thyroid Surgery Ward III, The Affiliated Zhongshan Hospital of Dalian University Dalian 116001, Liaoning Province, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wan
authors.affiliation: Breast and Thyroid Surgery Ward III, The Affiliated Zhongshan Hospital of Dalian University Dalian 116001, Liaoning Province, China.
authors.forename: Yongqiang
authors.initials: Y
authors.lastname: Yao
keywords: PTEN; Triple-negative breast cancer; microRNA-21; migration; proliferation