Downregulation of matrix metalloproteinase 14 by the antitumor miRNA, miR-150-5p, inhibits the aggressiveness of lung squamous cell carcinoma cells

Abstract

In the present study, in order to elucidate the aggressive nature of lung squamous cell carcinoma (LUSQ), we investigated the oncogenic RNA networks regulated by antitumor microRNAs (miRNAs or miRs) in LUSQ cells. The analysis of our original miRNA expression signatures of human cancers revealed that microRNA‑150‑5p (miR‑150‑5p) was downregulated in various types of cancer, indicating that miR‑150‑5p acts as an antitumor miRNA by targeting several oncogenic genes. Thus, the aims of this study were to investigate the antitumor roles of miR‑150‑5p in LUSQ cells and to identify oncogenes regulated by miR‑150‑5p that are involved in the aggressive behavior of LUSQ. The downregulation of miR‑150‑5p was validated in clinical samples of LUSQ and cell lines (SK-MES‑1 and EBC‑1). The ectopic overexpression of miR‑150‑5p significantly suppressed cancer cell aggressiveness. Comprehensive gene expression analyses revealed that miR‑150‑5p regulated 9 genes in the LUSQ cells. Among these, matrix metalloproteinase 14 (MMP14) was found to be a direct target of miR‑150‑5p, as shown by luciferase reporter assay. The knockdown of MMP14 using siRNA against MMP14 (si-MMP14) significantly inhibited cancer cell migration and invasion. The overexpression of MMP14 was detected in clinical specimens of LUSQ by immunohistochemistry. On the whole, these findings suggest that the downregulation of miR‑150‑5p and the overexpression of MMP14 may be deeply involved in the pathogenesis of LUSQ.

Involvement of dual‐strand of the miR‐144 duplex and their targets in the pathogenesis of lung squamous cell carcinoma

“…The procedure for qRT‐PCR has been described previously . The expression levels of miRNAs were analyzed by TaqMan qRT‐PCR assays (assay IDs 002148 and 002676; Applied Biosystems, Foster City, CA, USA).…”

“…After cotransfecting miRNA and the constructed vector into EBC‐1 and SK‐MES‐1 cells, firefly and Renilla luciferase activities were measured using a dual Luciferase assay kit (Promega). The procedure was described previously …”

“…The procedures for western blotting and immunohistochemistry were described previously . Membranes were immunoblotted with monoclonal anti‐NCS1 Abs (1:1000 dilution; ab129166; Abcam, Cambridge, UK) and monoclonal anti‐GAPDH Abs (1:20 000 dilution; MAB374; EMD Millipore, Billerica, MA, USA).…”

“…The characteristics of patients included in the tissue microarray are described in Table . The procedure for immunohistochemistry was described previously …”

“…Through our continuing work, we have identified antitumor miRNAs and their target oncogenic genes in LUSQ . Moreover, detailed analyses of our original miRNA expression signatures by RNA sequencing have revealed that passenger strands of miRNAs actually act as antitumor miRNAs and are involved in cancer pathogenesis .…”