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...