Reciprocal regulation of PCGEM1 and miR-145 promote proliferation of LNCaP prostate cancer cells

Prostate cancer gene expression marker 1 (pcgem1) is a long non-coding rna (lncrna) overexpressed in prostate cancer (pca) cells that promotes pca initiation and progression,and protects against chemotherapy-induced apoptosis. the microrna mir-145 functions as a tumor suppressor in pca. we speculate that reciprocal regulation of pcgem1 and mir-145 promote proliferation of lncap prostate cancer cells. to test this hypothesis,the interaction between pcgem1 and mir-145 was examined using a luciferase reporter assay. expression levels were selectively altered in lncap cells and noncancerous rwpe-1 prostate cells by transfection of mir-145 or small interfering rna sequences against (sirna) pcgem1. relative expression levels were detected by rt-pcr,tumor cell growth and early apoptosis by the mtt assay and flow cytometry,respectively,and tumor cell migration and invasion properties by transwell assays. the effect of sirna pcgem1 and mir-145 transfection on prostate cancer growth in vivo was examined in the (nu/nu) mouse model. pcgem1 and mir-145 exhibited reciprocal regulation; downregulation of pcgem1 expression in lncap cells increased expression of mir-145,while overexpression of mir-145 decreased pcgem1 expression. transfection of the mir-145 expression vector and sirna pcgem1 inhibited tumor cell proliferation,migration,and invasion,and induced early apoptosis both in vitro. in contrast,there was no effect on rwpe-1 cells. we demonstrate a reciprocal negative control relationship between pcgem1 and mir-145 that regulates both lncap cell proliferation and nu/nu pca tumor growth. the results also identify pcgem1 and associated regulators as possible targets for pca therapy. © 2014 he et al.; licensee biomed central ltd.