Role of microRNA-19b in proliferation and metastasis of pancreatic ductal adenocarcinoma

Abstract

Objective To examine the expression of miR-19b in pancreatic ductal adenocarcinoma (PDAC) cell lines, and invetigate the functional role of miR-19b in proliferation, migration and invasion of PDAC cells. Methods Real-time quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR) was used to detect the expression level of miR-19b in human pancreatic ductal epithelial cell line (HPDE), human PDAC cell lines (PANC1, MiaPaCa2 and BxPC3) and huamn PDAC metastasis cell line COLO357 and its fast-growing variant FG. PDAC cell lines stably over-expressing of low expressing miR-19b were constructed. Transwell assay and Matrigel assay were carried out to examine the migration and invasion capabities of PDAC cells with miR-19b down-regulated or up-regulated. Methyl thiazol tetrazolium (MTT) and colony formation assay were performed on PDAC cell lines with miR-19b silenced or overexpressed. Results The results of RT-qPCR showed the expression level of miR-19b in human PDAC cell lines PANC1, MiaPaCa2, BxPC3 and metastatic cell line COLO357 and FG (198.45±21.22, 221.37±18.59, 182.51±13.48, 317.64±15.20, 331.34±17.18) was significantly higher than that in HPDE (98.21±14.54), (P=0.003, 0.005, 0.021, 0.001, 0.001) and the difference was statistically significant. Transwell cell migration assay and Matrigel cell invasion assay revealed that the migration and invasion ability of FG cells after miR-19b silencing [(22.54±2.87)%, (28.87±5.62)%] was significantly decreased as compared with the control group [(99.65±3.07)%, (98.73±4.38)%], (P=0.005, 0.002) and the difference was statistically significant. In contrast, the migration and invasion ability of BxPC3 cells overexpressing miR-19b [(317.53±10.21)%, (286.77±12.83)%] was significantly higher than that in the control group [(97.89±5.31)%, (98.25±7.57)%] (P=0.003, 0.007) and the difference was statistically significant. The colony formation and MTT assay showed that after miR-19b silencing, the expression of p21 and p27 in PDAC cells was significantly reduced as compared with the control group (P=0.003, 0.005) and the difference was statistically significant. The results of Western blotting indicated that the silencing of miR-19b resulted in the up-regulation of p21 and p27 in PDAC cells by (3.25±0.27, 5.38±0.33) as compared with the control group (P=0.003, 0.001) and the difference was statistically significant. The overexpression of miR-19b led to the down-regulation of p21 and p27 by (2.68±0.15, 3.27±0.27) as compared with the control group (P=0.006, 0.005) and the difference was statistically significant. Conclusion MiR-19b could promote the migration and invasion of PDAC cells and increase the proliferation capability. Key words: MicroRNA-19b; Pancreatic ductal adenocarcinoma; Metastsis; Proliferation