Abstract: ponding Author E-mail: gl-gump Abstract: Objective To investigate the effects of cytokeratin 18 (CK18) gene on proliferation, apoptosis and invasion of human breast cancer BT549 cells, and to explore the molecular mechanism. Methods CK18 stably silencing BT549 cell line was established and divided into blank control group, negative control group and CK18-shRNA group. The cells with CK18 target silencing were used as the CK18-shRNA group, the empty vector was used as the negative control group (sh Con), and the blank control group (Wt) was not treated. The established cell line was identified by Western blot assay (WB). Cell proliferation was detected by cell counting kit-8 (CCK-8) assay and colony formation assay. Cell apoptosis was analyzed by flow cytometry of Annexin V/PE double staining kit, and cell cycle analysis was detected by PI-FACS. Migration and invasion capability were measured by the Scratch assay and Transwell assay. Western blot assay was used to detect the metastasis-related molecules of E-cadherin and vimentin protein expression. Results CK18 silencing BT549 cell line was established. The WB result indicated that the expression of CK18 was significantly inhibited, and the inhibition rate was up to 73%. It was shown that the BT549 cell proliferation was obviously depressed in the time-dependent manner at the time points of 24 h, 48 h and 72 h in CK18-shRNA group with the comparison to blank control group and negative control group. Compared with the blank control group and negative control group, the migration and invasion ability were decreased in CK18-shRNA group, and the apoptosis rate and the ratio of cells in G2 phase were increased in CK18-shRNA group (P＜ 0.05). WB showed that the decreased expression of CK18 also promoted the expression of E-cadherin and depressed the expression of vimentin (P＜0.05). Conclusion CK18 gene silencing in BT549 cells can inhibit cell proliferation, migration and invasion, and induce apoptosis and arrest cell cycles. CK18 may play a role in metastasis process of breast cancer BT549 cells by inducing EMT.

Key words: keratin 18;, breast neoplasms, cell proliferation, apoptosis