In the present study, the therapeutic effects and the underlying molecular mechanisms of microRNA (miR)‑145 were investigated in non‑small cell lung cancer (NSCLC) cells. Reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) was performed to examine miR‑145 expression. An MTT assay and flow cytometry were used to investigate cell proliferation and apoptosis, respectively. The protein expression of Bax, epidermal growth factor receptor (EGFR), phosphatidylinositol 3‑kinase (PI3K) and phosphorylated‑protein kinase B (AKT) was examined by western blot analysis. miR‑145 expression was downregulated in patients with NSCLC who were treated with chemotherapy. The downregulation of miR‑145 in A549 cells reduced lactate dehydrogenase (LDH) expression, apoptosis, caspase‑3/-9 levels and Bax protein expression, while it increased cell proliferation. Upregulation of miR‑145 in A459 cells increased LDH, apoptosis, caspase‑3/-9 levels and Bax protein expression, while it inhibited cell proliferation. The EGFR/PI3K/AKT signaling pathway was suppressed by miR‑145 upregulation in A549 cells and induced by miR‑145 downregulation. The EGFR inhibitor suppressed the EGFR/PI3K/AKT signaling pathway and increased the anticancer effects of miR‑145 upregulation in A549 cells. The PI3K inhibitor suppressed the PI3K/AKT signaling pathway and reversed the anticancer effects of miR‑145 upregulation in A549 cells. In conclusion, the present study demonstrated that miR‑145 regulates the EGFR/PI3K/AKT signaling pathway in patients with NSCLC.

Abstract. The present study determined the anticancer activity and its mechanism of microRNA-133b on cell proliferation of cisplatin-induced non-small cell lung cancer cells. The expression of microRNA-133b cisplatin-induced non-small cell lung cancer (NSCLC) tissue was lower than that of para-carcinoma tissue in patients. Overall survival of higher expression in cisplatin-induced NSCLC patients was higher than that of lower expression in cisplatin-induced NSCLC patients. Over-regulation of microRNA-133b inhibited cell proliferation and LDH activity, induced apoptosis and caspase-3 activity, suppressed the protein expression of EGFR, PI3K, p-Akt, p-JAK2 and p-STAT3, decreased cyclin D1 and increased Bax protein expression in cisplatin-induced A549 cells. EGFR inhibitor (lapatinib) suppressed EGFR protein expression, inhibited cell proliferation and LDH activity, and induced apoptosis and caspase-3 activity in cisplatininduced A549 cells by over-regulation of microRNA-133b. When EGFR protein expression was suppressed, PI3K, p-Akt, p-JAK2 and p-STAT3, decreased cyclin D1 and increased Bax protein expression in cisplatin-induced A549 cells by over-regulation of microRNA-133b. Altogether, our results indicated that over-regulation of microRNA-133b inhibits cell proliferation of cisplatin-induced NSCLC by PI3K/Akt and JAK2/STAT3 signaling pathway by targeting EGFR.

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Lung cancer is the leading cause of cancer-related death worldwide. MicroRNAs (miRNAs) in circulating small extracellular vesicles (sEVs) have been suggested to be potential biomarkers for cancer diagnosis. The present study was designed to explore whether plasma-derived sEV miRNAs could be utilized as diagnostic biomarkers for differentiating between early-stage small cell lung cancer (SCLC) and early-stage non-small cell lung cancer (NSCLC). We compared the miRNA profiles of plasma-derived sEVs from healthy individuals, patients with early-stage SCLC and patients with early-stage NSCLC. Next-generation sequencing was used to screen for differentially expressed miRNAs (DEMs). Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were used to predict the potential functions of these DEMs. Weighted gene coexpression network analysis (WGCNA) was used to identify the different pathology-related miRNA modules. We found that 22 DEMs were significantly different among healthy individuals, patients with early-stage SCLC, and patients with early-stage NSCLC. We selected six representative DEMs for validation by qRT‒PCR, which confirmed that miRNA-483-3p derived from plasma sEVs could be used as a potential biomarker for the diagnosis of early-stage SCLC, miRNA-152-3p and miRNA-1277-5p could be used for the diagnosis of early-stage NSCLC respectively.

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