Hsa-miR-329 exerts tumor suppressor function through down-regulation of MET in non-small cell lung cancer.

Cheng-Cao Sun,De-Jia Li,Cui-Li Yang,Liang Wang,Feng Zhang,Jing-Yu Pan,Yong-Yong Xi,Shu-Jun Li

doi:10.18632/oncotarget.7517

Abstract

MicroRNAs (miRNAs) act as key regulators of multiple cancers. Hsa-miR-329 (miR-329) functions as a tumor suppressor in some malignancies. However, its role on lung cancer remains poorly understood. In this study, we investigated the role of miR-329 on the development of lung cancer. The results indicated that miR-329 was decreased in primary lung cancer tissues compared with matched adjacent normal lung tissues and very low levels were found in a non-small cell lung cancer (NSCLC) cell lines. Ectopic expression of miR-329 in lung cancer cell lines substantially repressed cell growth as evidenced by cell viability assay, colony formation assay and BrdU staining, through inhibiting cyclin D1, cyclin D2 and up-regulatiing p57(Kip2) and p21(WAF1/CIP1). In addition, miR-329 promoted NSCLC cell apoptosis, as indicated by up-regulation of key apoptosis gene cleaved caspase-3, and down-regulation of anti-apoptosis gene Bcl2. Moreover, miR-329 inhibited cellular migration and invasiveness through inhibiting matrix metalloproteinases (MMP)-7 and MMP-9. Further, oncogene MET was revealed to be a putative target of miR-329, which was inversely correlated with miR-329 expression. Furthermore, down-regulation of MET by siRNA performed similar effects to over-expression of miR-329. Collectively, our results demonstrated that miR-329 played a pivotal role in lung cancer through inhibiting cell proliferation, migration, invasion, and promoting apoptosis by targeting oncogenic MET.

Highlights

Lung cancer is the leading cause of cancerrelated deaths both in men and women around the world for several decades
We examined miR-329 expression in non-small cell lung carcinomas (NSCLC) cell lines, and results demonstrated a lower expression of miR-329 in A549, SK-MES-1, SPC-A-1, H1299, 95-D and NCI-H520 cell lines, compared with that of in normal lung cells HELF (Figure 1B and Figure S1A)
Our results discovered that miR-329 significantly decreased the protein and mRNA expression of cyclin D1, while loss of miR-139-5p remarkably increased the level of cyclin D1 in A549 and H1299 cells (Figure 5C). cyclin D2 is highly expressed and promotes tumorigenesisin numerous tumors

Summary

Introduction

Lung cancer is the leading cause of cancerrelated deaths both in men and women around the world for several decades. At early stages of NSCLC, the only treatment is surgery, with a 5-year overall survival rate of 40% [2], whereas chemotherapy is mostly employed for small cell lung cancer (SCLC). These changes are attributed to silencing of tumor suppressor genes, dysregulation of proto-oncogenes, and an up-regulation of genes that promote cell growth and transformation and tumor development [3]. MiRNAs, a class of ~20 - 23 nucleotide (nt) noncoding RNAs, repress the expression of their target genes through binding mRNAs at specific sequences. The function and molecular mechanism of miR329 in human NSCLC are still elusive

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Conclusion