Abstract
MicroRNA-19b (miR‑19b) is part of the miR‑17‑92 cluster which is associated with cardiac development. It has previously been reported that the overexpression of miR‑19b increases proliferation, inhibits apoptosis and promotes differentiation of embryonic carcinoma cells (P19 cells). The aim of the current study was to investigate the effects of miR‑19b knockdown on the proliferation, apoptosis, differentiation and regulation of the Wnt/β‑catenin signaling pathway in P19 cells. P19 cells were transfected with an miR‑19b knockdown plasmid or an empty vector. MiR‑19b knockdown or vector control stable cell lines were selected using puromycin. Cell Counting kit‑8 and flow cytometry were used to analyze the levels of cellular proliferation, cell cycle progression and the levels of apoptosis, respectively. Caspase‑3 activity and mitochondrial function assays were also used to analyze apoptosis. An inverted microscope was used to observe the morphological changes of P19 cells during differentiation. Reverse transcription‑quantitative polymerase chain reaction and western blot analysis were used to detect P19 cell differentiation markers and Wnt/β‑catenin signaling pathway‑related genes and their corresponding proteins. The results demonstrated that miR‑19b knockdown inhibited the proliferation and apoptosis of P19 cells. However, the levels of expression of Wnt and β‑catenin increased. MiR‑19b knockdown activated the Wnt/β‑catenin signaling pathway, which may regulate cardiomyocyte differentiation. The results of this study indicate that miR‑19b is a novel therapeutic target for cardiovascular diseases and provide insight into the mechanisms underlying congenital heart diseases.