Abstract
Considering the joint contribution of long non‑coding RNAs (lncRNAs) and microRNAs (miRNAs/miRs) to tumorigenesis, the aim of the present study was to investigate whether and how lncRNA H19 targets miR‑29b‑3p to affect the progression of lung adenocarcinoma by the modulation of signal transducer and activator of transcription 3 (STAT3). A total of 305 lung adenocarcinoma tissues and four human lung adenocarcinoma cell lines (i.e. Calu‑3, NCI‑H1975, A549 and NCI‑H23) were used. pcDNA3.1‑H19, short interfering RNA (si‑)H19, miR‑29b‑3p mimic, miR‑29b‑3p inhibitor and negative control (NC) were transfected into the cells, and the proliferation, viability and apoptosis of the cells were determined using a Cell Counting Kit‑8 assay, colony formation assay and flow cytometry, respectively. The results indicated that highly expressed H19 and poorly expressed miR‑29b‑3p could serve as predictors for the poor prognosis of lung adenocarcinoma patients. Additionally, si‑H19 and miR‑29b‑3p mimic significantly increased the apoptosis of lung adenocarcinoma cells, and decreased the survival rate and viability of cells. Simultaneously, expression of epithelial‑mesenchymal transition (EMT)‑specific proteins was significantly altered, i.e. increased epithelial cadherin expression, as well as decreased vimentin, Snail and Slug expression. Furthermore, miR‑29b‑3p was verified to be targeted and regulated by H19, and STAT3 was targeted and modified by miR‑29b‑3p. Ultimately, STAT3 was identified to decrease lung adenocarcinoma cell viability, survival, apoptosis and EMT imposed by miR‑29b‑3p. In conclusion, the results of the present study indicated that lncRNA H19/miR‑29b‑3p/STAT3 signaling was involved in the development of lung adenocarcinoma, which may be critical for developing effective diagnostic and treatment strategies for lung adenocarcinoma.