|miR-145 inhibits breast cancer cell growth through RTKN|
Authors: Shihua Wang, Chunjing Bian, Zhuo Yang, Ye Bo, Jing Li, Lifen Zeng, Hong Zhou, Robert Chunhua Zhao
Center of Tissue Engineering, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, Beijing 100005, P.R. China
MicroRNAs (miRNAs) represent a class of small non-coding RNAs regulating gene expression by inducing RNA degradation or interfering with translation. Aberrant miRNA expression has been described for several human malignancies. Herein, we show that miR-145 is down-regulated in human cancer cell line MCF-7 when compared to normal human mammary epithelial cell line MCF10A. Overexpression of miR-145 by plasmid inhibits MCF-7 cell growth and induces apoptosis. Subsequently, RTKN is identified as a potential miR-145 target by bioinformatics. Using reporter constructs, we show that the RTKN 3' untranslated region (3'UTR) carries the directly binding site of miR-145. Additionally, overexpression of miR-145 in MCF-7 reduces RTKN protein expression as well as mRNA level. Furthermore, down-regulation of RTKN by siRNA can inhibit MCF-7 cell growth. Taken together, we propose that loss of miR-145 may provide a selective growth advantage for MCF-7 by targeting RTKN.