Abstract: Liu Xilin, Jian Qiang, Miao Ye, Huang Min, Li Chengxin. Department of Dermatology, Xijing Hospital, Fourth Military Medical University, Xi′an 710032, China Corresponding author: Li Chengxin, Email: chengxinderm@163.com 【Abstract】 Objective To evaluate the effect of Rab23 on the proliferation of a squamous cell carcinoma cell line Sa3, and to investigate its mechanisms. Methods Cultured Sa3 cells were classified into four groups: normal control group transfected with green fluorescent protein （GFP）, Rab23-overexpressing group transfected with a GFP-labelled Rab23-overexpressing plasmid, Rab23-silencing group transfected with a plasmid carrying a Rab23-targeting shRNA, empty vector group transfected with an empty vector. After additional culture for different durations, plate colony formation assay and flow cytometry were performed to evaluate the proliferative activity of Sa3 cells, and Western blot was conducted to detect the expression of Erk/phosphorylated-Erk in Sa3 cells. Statistical analysis was carried out by t test, one-way analysis of variance and Bonferroni′s multiple comparison test. Results Stable Sa3 cell lines with overexpression or silencing of Rab23 were established by plasmid construction and lentivirus-mediated transfection. The plate colony formation assay showed that the colony formation rate was significantly lower in the Rab23-overexpressing group than in the normal control group （2.3% ± 0.2% vs. 3.6% ± 0.3%, P < 0.05）, but higher in the Rab23-silencing group than in the empty vector group （4.1% ± 0.2% vs. 1.8% ± 0.03%, P < 0.01）. Rab23 overexpression induced G1 phase arrest in Sa3 cells. The proliferation index was significantly decreased in the Rab23-overexpressing group compared with the normal control group（0.581 ± 0.035 vs. 0.698 ± 0.018, P < 0.05）, but increased in the Rab23-silencing group compared with the empty vector group （0.567 ± 0.015 vs. 0.444 ± 0.014, P < 0.01）. As Western blot showed, there were no significant changes in the expression of Erk in the Rab23-silencing or -overexpressing group compared with the normal control group, whereas the expression of p-Erk was attenuated in the Rab23-overexpressing group compared with the normal control group, but enhanced in the Rab23-silencing group compared with the empty vector group. Conclusions Rab23 could inhibit the proliferation of Sa3 cells, which may be associated with the Erk pathway.

Key words: Rab23, Lentivirus infections, Carcinoma, squamous cell, Cell line, tumor, Cell proliferation