miRNA-19 promotes non-small-cell lung cancer cell proliferation via inhibiting CBX7 expression

BACKGROUND: miR-19 is a critical carcinogenic miRNA that participates in important biological processes of human malignancies. CBX7 plays a key role in lung cancer development and progression. In the present study, for the first time, we investigated the correlation between miR-19 and CBX7 in non-small-cell lung cancer (NSCLC). METHODS: miR-19 expression in NSCLC tissues and lung cancer cell lines was detected using quantitative reverse transcriptase PCR (qRT-PCR). Luciferase reporter assay, qRT-PCR, Western blot, and immunohistochemical assay were conducted to identify the target reaction of miR-19 and CBX7. Moreover, the influence of miR-19 on lung cancer cell proliferation, migration, and invasion was studied including cell counting kit-8 assay, scratch assay, transwell assay, flow cytometry assay, and staining assays. RESULTS: miR-19 was overexpressed in NSCLC tissues and lung cancer cell lines. Luciferase reporter assay demonstrated that miR-19 could inhibit CBX7 expression via binding to the 3′-UTR of CBX7. Furthermore, miR-19 remarkably decreased CBX7 protein and mRNA expression. Additionally, overexpression of miR-19 could significantly enhance lung cancer cell proliferation and migration. CONCLUSION: miR-19 functions as a tumor accelerator promoting lung cancer cell proliferation through targeting CBX7 and inhibiting its expression.