Matrix metalloproteinase 13: a potential intermediate between low expression of microRNA-125b and increasing metastatic potential of non–small cell lung cancer

Recent findings have suggested that microRNAs may be involved in the regulation of metastasis in malignant cancers such as non–small cell lung cancer (NSCLC). This study aimed to determine the relationship between expression of miR-125b and matrix metalloproteinase 13 (encoded by MMP-13) and the metastatic potential of cancer cells in NSCLC. Expression levels of miR-125b transcripts and MMP-13 proteins were analyzed by quantitative real-time PCR and immunohistochemistry, respectively, in tumor tissues and adjacent nontumor tissues from 42 patients with NSCLC. The interaction between miR-125b and MMP-13 expression and the associations between miR-125b and clinicopathologic data were analyzed. MiR-125 b expression levels were decreased in NSCLC tumor tissue samples, which correlated with an increased incidence of lymph node metastases, increased pathologic stage, increased MMP-13 expression levels, and decreased early progression-free survival. Additionally, we have demonstrated that increased levels of miR-125b can directly downregulate MMP-13 protein expression and inhibit the invasive capabilities of cancer cells. Expression levels of miR-125b were negatively correlated with metastatic potential of NSCLC tumors, which may function through regulation of MMP-13.