Downregulation of microRNA-362-3p and microRNA-329 promotes tumor progression in human breast cancer

Abstract

p130Cas regulates cancer progression by driving tyrosine receptor kinase signaling. Tight regulation of p130Cas expression is necessary for survival, apoptosis, and maintenance of cell motility in various cell types. Several studies revealed that transcriptional and post-translational control of p130Cas are important for maintenance of its expression and activity. To explore novel regulatory mechanisms of p130Cas expression, we studied the effect of microRNAs (miRs) on p130Cas expression in human breast cancer MCF7 cells. Here, we provide experimental evidence that miR-362-3p and miR-329 perform a tumor-suppressive function and their expression is downregulated in human breast cancer. miR-362-3p and miR-329 inhibited cellular proliferation, migration, and invasion, thereby suppressing tumor growth, by downregulating p130Cas. Ectopic expression of p130Cas attenuated the inhibitory effects of the two miRs on tumor progression. Relative expression levels of miR-362-3p/329 and p130Cas between normal and breast cancer correlated inversely; miR-362-3p/329 expression was decreased, whereas that of p130Cas increased in breast cancers. Furthermore, we showed that downregulation of miR-362-3p and miR-329 was caused by differential DNA methylation of miR genes. Enhanced DNA methylation (according to methylation-specific PCR) was responsible for downregulation of miR-362-3p and miR-329 in breast cancer. Taken together, these findings point to a novel role for miR-362-3p and miR-329 as tumor suppressors; the miR-362-3p/miR-329-p130Cas axis seemingly has a crucial role in breast cancer progression. Thus, modulation of miR-362-3p/miR-329 may be a novel therapeutic strategy against breast cancer. Cell Death and Differentiation (2016) 23, 484-495; doi:10.1038/cdd.2015; published online 4 September 2015 p130Cas/breast cancer anti-estrogen resistance 1 is a member of the Cas (Crk-associated substrate) family of adaptor proteins and has a central role in tyrosine kinasebased signaling related to cell adhesion, migration, cell cycle control, apoptosis, development, and cancer progression.

Mutual regulation of microRNAs and DNA methylation in human cancers

“…miR-362-3p and miR-329 were downregulated in human breast cancer and performed a tumor-suppressor function by inhibiting cellular proliferation. 15 miR-148a was downregulated in non-small cell lung cancer (NSCLC) and functioned as a tumor suppressor gene by modulating matrix metalloproteinase 15 (MMP15) and Rho-associated kinase 1 (ROCK1). 16 By contrast, miR-224 was upregulated in NSCLC tissues and promoted cell proliferation by targeting TNF a-induced protein 1 (TNFAIP1) and SMAD directly, indicating a function as a potent oncogenic miR.…”

The miR-24-3p/p130Cas: a novel axis regulating the migration and invasion of cancer cells

“…4A). Our previous studies and others indicated that p130Cas is a proto-oncogene governing cell migration/invasion and its differential expression is related to cancer progression15162027. To test whether miR-24-3p regulates p130Cas expression, we investigated p130Cas expression in MCF7 cells after the transfection of miR-24-3p.…”

“…4), we further investigated whether the negative regulation of miR-24-3p on cell migration/invasion was mediated by direct targeting of p130Cas. We generated stable MCF7 cell lines expressing EGFP or EGFP-Cas (MCF7_Control or MCF7_EGFP-Cas)20 and assessed the cell migration after miR-24-3p overexpression in stable cell lines. As shown in Fig.…”

“…Human prostate carcinoma PC-3 and mouse melanoma B16F10 cells were maintained in Roswell Park Memorial Institute medium (RPMI) (Hyclone, CA), supplemented with 10% fetal bovine serum and 1% penicillin/streptomycin. MCF7 clones stably expressing either pEGFP or pEGFP-p130Cas were also maintained in DMEM/10% FBS/1% penicillin/streptomycin with 0.5 mg/ml of G41820. EGFP reporter plasmids were cloned by inserting 3′UTR of human p130Cas mRNA (3002–3150 bp) into pEGFP-C1 (BD Bioscience, NJ) as described in a previous study21.…”

“…Posttranslational regulation of p130Cas such as proteolytic cleavage or reversible phosphorylation of tyrosine residues are known to be essential for p130Cas activity1819. In addition, miRNAs were also involved in the regulation of p130Cas expression; miR-362-3p and miR-329 suppressed cancer progression by targeting p130Cas20.…”