Non-small cell lung cancer (NSCLC) is the most common type of lung cancer accounting for ~80% of lung cancer cases. According to novel research, numerous microRNAs (miRs) have been suggested to function as important regulators of cancer. In addition, the expression of miR-140-5p is decreased in patients with NSCLC. Therefore, it is important to further elucidate the role of miR-140-5p in NSCLC. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used in order to investigate the expression of miR-140-5p in NSCLC tissues and matched normal tissues and to determine miR-140-5p levels following transfection with mimics into A549 lung cancer cells. Targetscan software was used to predict the oncogene target of miR-140-5p. This analysis revealed that YES proto-oncogene 1 (YES1) includes a target site for miR-140-5p binding. The results revealed that YES1 is a potential target gene of miR-140-5p, and this was further confirmed by the results of luciferase reporter assays, which demonstrated that miR-140-5p directly targeted the predicted binding site in the 3'-untranslated region of YES1. Cell Counting Kit-8 (CCK-8) and flow cytometry assays were performed to determine the levels of cell viability and apoptosis. Western blot assays was performed to investigate the expression levels of YES1 and proteins associated with apoptosis in A549 cells following transfection. The results revealed that miR-140-5p expression was significantly downregulated in NSCLC tissues compared with matched normal tissues. The expression of miR-140-5p was significantly increased following transfection with miR-140-5p mimics. The results of CCK-8 and flow cytometry assays indicated that miR-140-5p inhibited proliferation and induced apoptosis of tumor cells. Western blot analysis and RT-qPCR revealed that YES1 and B-cell lymphoma 2 (Bcl-2) mRNA and protein expression levels were markedly decreased in A549 cells, while Bcl-2 associated X (Bax) and caspase-3 expression levels increased significantly following transfection with miR-140-5p mimics compared with the negative control group. In conclusion, miR-140-5p may induce apoptosis in A549 cells by targeting YES1 and regulating the expression of apoptosis-associated proteins Bcl-2, Bax and caspase-3.

Abstract. Nimotuzumab, a humanized IgG1 monoclonal antibody against epidermal growth factor receptor (EGFR), increases radiosensitivity in lung cancer. Cisplatin is an effective antitumor agent in lung cancer. In the present study, the antitumor activity of nimotuzumab combined with cisplatin was investigated in A549 lung cancer cells. Viability, cell cycle distribution and cyclin D1 expression were assessed following treatment with nimotuzumab alone, cisplatin alone, nimotuzumab in combination with cisplatin, and nimotuzumab followed sequentially by cisplatin. The inhibitory effect on cell viability of nimotuzumab sequentially followed by cisplatin was higher compared with cisplatin alone (82.17±1.62 vs. 56.97±1.42%). Compared with treatment by cisplatin alone, cell cycle analysis by flow cytometry demonstrated that the percentage of cells in the G 0 /G 1 phase was increased when A549 cells were treated with nimotuzumab followed sequentially by cisplatin (P<0.01). However, the proportion of cells in G 0 /G 1 phase was decreased when A549 cells were treated with nimotuzumab and cisplatin simultaneously compared with cisplatin alone (P<0.05). Cyclin D1 expression was decreased in all chemotherapy treatment groups; the most significant decrease was in A549 cells treated with nimotuzumab followed sequentially by cisplatin. Nimotuzumab may enhance the antitumor activity of cisplatin on A549 cells. The cell cycle arrest at G 0 /G 1 observed may have been due to decreased cyclin D1 levels. Potential antagonism was identified when A549 cells were treated with nimotuzumab and cisplatin simultaneously, indicating that targeted therapy may be more effective when administered prior to conventional chemotherapy. IntroductionLung cancer has been the most common cancer worldwide, and the leading cause of cancer-associated mortality, since 1985 (1). The 5-year survival rate for lung carcinoma overall is poor, at 16-17% (2). Surgery is not suitable for the majority of patients with lung cancer, as diagnoses are often obtained at advanced disease stages. The standard of care for advanced non-small cell lung cancer (NSCLC) is cisplatin in combination with 1 to 3 of the following drugs: Paclitaxel, gemcitabine and docetaxel (3). The efficacy of chemotherapy is limited due to its side effects and the lack of response in certain sub-populations of patients. Research efforts have focused on identifying molecular targets and developing molecular-targeted therapies based on the understanding of the molecular abnormalities associated with lung cancer (4-6).Insight into the pathobiology of NSCLC has facilitated the development of targeted molecular therapies that target specific mutations that serve critical roles in the progression to aggressive disease. Mutations in the epidermal growth factor receptor (EGFR), KRAS and anaplastic lymphoma kinase (ALK) genes are mutually exclusive in patients with NSCLC, and targeted therapy may be affected due to the existence of one mutation in lieu of another. Therefore, the detection of these mutati...

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