Dongqi Gao, Jingjing Zhang, Lu Bai, Fubo Li, Yi Dong, Qingshan Li

Non-small-cell lung cancer (NSCLC) has one of the highest mortality rates among cancers worldwide, with a poor prognosis. Previous studies have reported that melittin, an active component of apitoxin, exerts anti-inflammatory and antitumor effects via vascular endothelial growth factor or FoxO1. CCK8, flow cytometry assay and Western blotting were performed to evaluate the effect of melittin on NSCLC. The present study demonstrates that melittin activated caspase-2 by inhibiting miR-183 expression and, thus, induced NSCLC apoptosis in both NCI-H441 cancer cell line assays and an in vivo xenograft model. The results of the cell-based assays showed that melittin (2 μg/mL) robustly suppressed miR-183 expression level and resulted in decreased invasion and migration abilities of NCI-H441 cells. Additionally, a flow cytometry assay and Western blotting showed that melittin induced NSCLC NCI-H441 cell apoptosis along with significant elevation of caspase-2 and Bax, which are regulators of cell apoptosis, and reduced Bcl-2 protein expression compared with dimethyl sulfoxide control. Furthermore, subcutaneous injection of melittin (5 mg/kg) significantly suppressed NSCLC tumor growth compared with vehicle group tumors, determined through tumor size and weight. Taken together, the aforementioned findings contribute to identification of a novel therapeutic target in the treatment of NSCLC, in patients diagnosed with a high expression of miR-183. Moreover, this article provides solid evidence for the inhibitory effect of melittin on NSCLC cancer cell growth.