Overexpression of microRNA-19a-3p promotes lymph node metastasis of esophageal squamous cell carcinoma via the RAC1/CDC42-PAK1 pathway

BACKGROUND: A tendency towards extensive regional lymph node metastasis (LNM) is a typical clinical characteristic of esophageal squamous cell carcinoma (ESCC). Up-regulated microRNA (miR)-19a-3p was verified as a predictor of LNM in ESCC in previous microarray analyses, but the underlying mechanisms remain unclear. Here, in vitro experiments were performed to confirm the effect of miR-19a-3p on promoting LNM and to explore the underlying mechanisms. METHODS: KYSE-150 and TE-1 cell lines were transfected with lentiviral vectors to inhibit miR-19a-3p (LV-miR-19a-3p-inhibition), and cell proliferation, invasion, and migration were assessed. Target genes of miR-19a-3p were identified by sequencing analysis and quantitative reverse transcription PCR (qRT-PCR); Western blotting was performed to confirm targets and explore the potential mechanisms underlying the effect of miR-19a-3p on LNM. RESULTS: miR-19a-3p had no effect on ESCC cell proliferation, whereas miR-19a-3p overexpression promoted the invasion and migration of ESCC cells. qRT-PCR verification and western blot analysis showed that LV-miR-19a-3p-inhibition downregulated cell division cycle 42 (CDC42), Rac family small GTPase 1 (RAC1), and p21 activated kinase 1 (PAK1). CONCLUSIONS: Overexpression of miR-19a-3p increased the invasion and migration of ESCC cells via the RAC1/CDC42-PAK1 pathway, suggesting that this pathway mediates the effect of miR-19a-3p on promoting LNM in ESCC.