Abstract: Xia Yonghua, Hou Huifang, Li Min, Zhang Caifeng, Liu Dong, Hu Hua, Zhang Mengjie, Cheng Sai Department of Dermatology, The First Affiliated Hospital of Xinxiang Medical University, Weihui 453100, Henan, China （Xia YH, Li M, Liu D, Hu H, Zhang MJ, Cheng S）; Department of Gastroenterology, The First Affiliated Hospital of Xinxiang Medical University, Weihui 453100, Henan, China （Zhang CF）; Department of Pathophysiology, School of Basic Medical Sciences, Xinxiang Medical University, Weihui 453100, Henan, China （Hou HF） Corresponding author: Xia Yonghua, Email: 751195651@qq.com 【Abstract】 Objective To investigate the of microRNA-373 （miR-373） in cutaneous squamous cell carcinoma （CSCC） tissues and cells, and to explore its effects on cell invasion. Methods Real-time PCR was performed to determine the of miR-373 in CSCC tissues and paralesional normal skin tissues, as well as in CSCC cell lines （A431 and SCL-1） and HaCaT cells. A431 cells were divided into 4 groups: miR-373 mimic group, miR-373 inhibitor group and negative control group which were transfected with miR-373 mimic, miR-373 inhibitor and negative control miRNA respectively, and untreated group receiving no treatment. Cell invasion assay was performed to evaluate effects of miR-373 downregulation on cell invasion. Western blot analysis was conducted to assess effects of miR-373 downregulation on the protein of matrix metalloproteinase-2 （MMP-2） and MMP-9. Results Expression of miR-373 was significantly higher in the CSCC tissues（2.465 ± 0.218） than in the paralesional normal skin tissues （1.000 ± 0.000, P < 0.05）, and higher in SCL-1 cells （1.864 ± 0.178） and A431 cells（2.919 ± 0.277） than in HaCaT cells （1.000 ± 0.000, P < 0.05）. Most notably, miR-373 was also markedly higher in metastatic CSCC tissues than in non-metastatic CSCC tissues （3.323 ± 0.344 vs. 1.914 ± 0.161, t = 4.158, P = 0.000 4）. Compared with the untreated group and negative control group, the miR-373 mimic group showed significantly increased miR-373 and invasive ability, while the miR-373 inhibitor group showed markedly decreased miR-373 and invasive ability （all P < 0.05）. Conclusion MiR-373 downregulation can significantly suppress the invasion of A431 cells, and obviously decrease the protein of MMP-2 and MMP-9.

Key words: Neoplasms, squamous cell, Skin, MicroRNAs, Neoplasm metastasis, MicroRNA-373