Effects And Mechanisms Of 8-chloro-adenosine On Breast Cancer Cells Via ADAR1-regulated MiR-335-5p

Objective:To investigate the effects of 8-chloro-adenosine(8-Cl-Ado)on the proliferation,migration and invasion of breast cancer cells by regulating adenosine deaminases acting on RNA1(ADAR1),analyze the correlation between ADAR1 and miR-335-5p,and its mechanisms of action in breast cancer cells.Methods:After treating breast cancer cells MDA-MB-231 and MCF-7 with10?mol/L 8-Cl-Ado at different time points,the proliferation was examined by CCK-8,the migration and invasion were determined by Transwell,and the expression levels of ADAR1 were measured by Western blotting.Up-regulated miRNAs were screened by miRNA microarray and confirmed by qRT-PCR.The effect of miR-335-5p overexpression on the proliferation of breast cancer cells was evaluated by CCK-8.The effects of miR-335-5p overexpression on the migration and invasion of breast cancer cells were examined by Transwell.After ADAR1 or miR-335-5p overexpression,theexpression levels of EMT related proteins were examined by Western blotting.Results:1.10?mol/L 8-Cl-Ado inhibited the proliferation,migration and invasion of breast cancer cells.2.The protein expression of ADAR1 gradually decreased in a time dependent manner after 8-Cl-Ado treatment.3.miR-335-5p was a tumor suppressor gene in breast cancer cells,and it was up-regulated after 8-Cl-Ado treatment.4.ADAR1 down-regulated the expression of miR-335-5p.5.miR-335-5p overexpression could inhibit the proliferation,migration and invasion of breast cancer cells.6.After ADAR1 overexpression,Twist1 and Vimentin protein expression increased while E-cadherin protein expression decreased.7.After miR-335-5p overexpression,Twist1 and Vimentin protein expression decreased while E-cadherin protein expression increased.Conclusion:1.ADAR1 is a potential target of 8-Cl-Ado against breast cancer,8-Cl-Ado inhibits the proliferation,migration and invasion of breast cancer cells through down-regulating ADAR1.2.ADAR1 can down-regulate the expression of miR-335-5p,8-Cl-Ado inhibits the proliferation,migration and invasion of breast cancer cells viaADAR1-regulated miR-335-5p.3.Twist1 is a target of miR-335-5p,and miR-335-5p inhibits the EMT process of breast cancer cells by targeting Twist1.