Abstract:

Objective To investigate the effect of circPTPRA on the proliferation，migration and invasion of breast cancer cell and its possible mechanism. Methods Cancer tissues and corresponding adjacent tissues of 41 breast cancer patients were collected，and the expression level of circPTPRA and miR ⁃ 556⁃3p in the tissues were detected by RT⁃qPCR. Breast cancer cells MDA⁃MB⁃231 were cultured in vitro and transfected with pcDNA⁃ circPTPRA，anti⁃miR⁃556⁃3p or co⁃transfected with pcDNA⁃circPTPRA and miR⁃556⁃3p. Cell proliferation was detected by CCK ⁃ 8 method. Transwell was used to detect cell migration and invasion，and western blotting was used to detect the protein expression of Ki⁃67，MMP⁃2，and MMP⁃9 in the cells. The dual luciferase reporter gene experiment verified the targeting relationship between circPTPRA and miR ⁃ 556⁃3p. Results The expression of circPTPRA in breast cancer tissues was lower than that of adjacent tissues（P < 0.05），while the expression of miR⁃ 556⁃3p was higher（P < 0.05）. After overexpression of circPTPRA or knockdown of miR⁃556⁃3p，the cell OD value，the number of migration and invasion，and the protein expression of Ki⁃67，MMP⁃2 and MMP⁃9 in MDA⁃MB⁃ 231 cells were reduced（P < 0.05）. circPTPRA negatively regulated the expression of miR⁃556⁃3p. Overexpression of miR⁃556⁃3p reversed the inhibitory effect of overexpression of circPTPRA on the proliferation，migration and invasion of MDA⁃MB⁃231 cells. Conclusion Overexpression of circPTPRA may hinder the proliferation，migra⁃ tion and invasion of breast cancer cells MDA⁃MB⁃231 by down⁃regulating the expression of miR⁃556⁃3p.

Key words:

breast cancer, circPTPRA, miR?556?3p, cell proliferation, migration, invasion