Abstract: 【Abstract】 Objective To evaluate the effect of overexpression of the autophagy marker gene Beclin1 on biological behaviors of SK-MEL-2 human malignant melanoma cells. Methods Western blot analysis was performed to determine the protein expression of Beclin1 in melanoma cell lines A375 and SK-MEL-2. SK-MEL-2 cells with low Beclin1 protein expression were selected as research objects, and divided into 3 groups: blank group receiving no treatment, negative control group transfected with pcDNA.3.1/myc-His （-） A, and experimental group transfected with pcDNA3.1-Beclin1 plasmid. After 2-week culture, cell counting kit-8 （CCK-8） assay was conducted to evaluate the effect of Beclin1 on cell proliferation at 24, 48 and 72 hours, and Transwell assay and wound-healing assay were performed to assess the effect of Beclin1 overexpression on the invasion and migration abilities of SK-MEL-2 cells. Repeated measures analysis of variance and completely randomized analysis of variance were used to analyze differences in indices among groups, and least significant difference （LSD）-t test was used for multiple comparisons. Results The protein expression of Beclin1 was significantly lower in the SK-MEL-2 cells （0.037 ± 0.010） than in the A375 cells （0.670 ± 0.150, F = 46.62, P＜0.05）. The experimental group showed significantly increased protein expression of Beclin1 （0.32 ± 0.04） compared with the negative control group （0.06 ± 0.02, P < 0.05） and blank group （0.07 ± 0.02, P < 0.05）. CCK-8 assay revealed a significant difference in the cell proliferation rate among different groups and different time points （F = 1 077.36, 4 903.04 respectively, both P＜0.05）, and there was a significant interaction between the transfection treatment and time （F = 205.20, P＜0.05）. Transwell assay showed that the number of SK-MEL-2 cells crossing the chamber per high-power field （× 200） after 24-hour treatment was significantly lower in the experimental group （18.67 ± 1.19） than in the negative control group （87.89 ± 6.05, P＜0.05） and blank group（86.78 ± 5.93, P＜0.05）. In the wound-healing assay, the cell migration distance was significantly shorter in the experimental group than in the blank group and negative control group at 24 and 48 hours （all P < 0.05）. Conclusion Beclin1 overexpression can markedly inhibit the proliferation, invasion and migration of SK-MEL-2 cells.

Key words: Autophagy, Melanoma, experimental , Cell proliferation, Cell migration assays, Beclin1