Abstract: Objective To investigate the anticancer effect of lobaplatin on human nasopharyngeal carcinoma（NPC） in vitro and the probable mechanisms to determine whether lobaplatin is a candidate for chemotherapy in human NPC.
Methods Three kinds of poorly differentiated human NPC cell lines CNE2， HONE1 and SUNE1 were engaged in this experiment. Cytotoxicity of lobaplatin in the cell lines was examined with CCK-8 cell viability assay. Cell cycle and apoptosis were determined by flow cytometry and the expressions of its related proteins were examined by Western blotting analysis.
Results Lobaplatin with different concentration showed evident inhibitory effect on the three kinds of poorly differentiated human NPC cell lines and there was increased in a concentration dependent manner. The proliferation of human NPC cell lines CNE2， HONE1 and SUNE1 were inhibited when they were treated with lobaplatin for 48h. The half maximal inhibitory concentration（IC₅₀） of three kinds of NPC cell lines CNE2, HONE1 and SUNE1 were （4.05±0.49）μmol/L，（4.32±1.17）μmol/L and （2.51±0.15）μmol／L，respectively. Lobaplatin arrested cell cycle progression in G₂ phase with increasing cyclin B1 and phospho-cdc2（Tyr15） proteins in lower doses， however， induced apoptosis with caspase3 cleaved in higher doses. Conclusion Lobaplatin shows anticancer effect on human NPC cells by means of cell cycle blockage and induction of apoptosis, which will contribute to the potential use of lobaplatin in the treatment of human NPC.