Abstract: Tao Yue*, Zhang Mengli, Ma Pengcheng, Sun Jianfang, Zhou Wuqing, Bao Jun. *Department of Dermatology, Nanjing Drum Tower Hospital, Nanjing 210008, China Corresponding authors: Ma Pengcheng, Email: mpc815@163.com；Sun Jianfang, Email: fangmin5758@aliyun.com 【Abstract】 Objective To study the effect of paeonol on the proliferation and apoptosis of A375 human melanoma cells and its mechanism. Methods Cell counting kit-8 （CCK8） was used to evaluate the proliferative activity of A375 cells treated with paeonol of 0.5，1，2，4，8 mmol/L for 24, 48 and 72 hours respectively. Subsequently, A375 cells were treated with paeonol of 1.25, 2.5 and 5 mmol/L for 24 hours followed by double staining with annexin Ⅴ and propidium iodide for the detection of cell apoptosis, fluorometric assay for the estimation of caspase 3, caspase 8 and caspase 9 activity, and Western blot for the determination of the levels of p53, nuclear factor-κB proteins and some of their target proteins. The A375 cells receiving no treatment served as the blank control group. Statistical analysis was carried out by t test. Results Within the investigated concentration and time ranges, paeonol significantly inhibited the proliferative activity of A375 cells in a concentration- and time-dependent manner. Compared with the blank control group, a significant increase was observed in the early apoptosis rate in A375 cells treated with paeonol of 1.25, 2.5 and 5 mmol/L for 24 hours （13.74% ± 1.73%, 25.95% ± 0.57% and 46.44% ± 0.81% vs. 3.11% ± 0.53%, P < 0.05 or 0.01）, as well as in the activity of caspase 3, 8 and 9 in A375 cells treated with paeonol of 2.5 and 5 mmol/L for 24 hours （P < 0.05 or 0.01）. After 24-hour treatment, the protein levels of p53 and Bax were elevated, but those of nuclear factor-κB, Bcl-2 and Bcl-XL were decreased in A375 cells with the increase of paeonol concentration. Conclusions Paeonol can inhibit the proliferation but induce the apoptosis of A375 cells, and the apoptosis-inducing effect may be realized through intrinsic and extrinsic pathways by modulating nuclear factor-κB and p53 genes.

Key words: Melanoma, experimental, Paeonol, Apoptosis, Cell proliferation