[Effect of CDK2-AP1 gene over-expression on proliferation and cell cycle regulation of breast cancer cell line MCF-7].

OBJECTIVE: To over-express cyclin-dependent kinase 2-associated protein 1 (CDK2-AP1) gene, and investigate its effect on the proliferation and cell cycle regulation in breast cancer cell line MCF-7. METHODS: CDK2-AP1 gene coding region was cloned into lentivirus vector. Lentivirus particles were infected into MCF-7 cells to upregulate the expression of CDK2-AP1 gene. The expression level of CDK2-AP1 was detected at both mRNA and protein levels by real-time PCR and Western blot. MTT assay, colony formatting assay, and flow cytometry were performed to detect the change of proliferation and cell cycle in MCF-7 cells. We examined the expression of cell cycle associated genes (CDK2, CDK4, P16Ink4A, and P21Cip1/Waf1) followed by CDK2-AP1 over-expression by Western blot. RESULTS: CDK2-AP1 gene was up-regulated significantly at both mRNA (6.94 folds) and protein level. MTT based growth curve, colony formatting assay and flow cytometry showed that CDK2-AP1 over-expression lentivirus inhibited the proliferation of MCF-7 cells with statistical difference (P<0.05). In addition, with CDK2-AP1 over-expression, MCF-7 cells were arrested in G1 phase accompanied by apoptosis. Western blot showed that the expression level of P21Cip1/Waf1 and P16 Ink4A was upregulated, while the expression level of CDK2 and CDK4, members of the CDK family, was downregulated. CONCLUSION: CDK2-AP1 gene plays a cancer suppressor role in breast cancer. Its function includes inhibiting the proliferation of MCF-7 cells and arresting the cell cycle in G1 phase.