Abstract:

Objective     To investigate effects of carboxypeptidase B2 (CPB2) gene silencing on expression of thrombin activated fibrinolysis inhibitor(TAFI) and growth and metastasis of the breast cancer cell line MDA-MB-231.  Methods    Cells were divided into five groups： the siRNA-1 group, the siRNA-2 group, the siRNA-3 group, the negative control group and the blank control group. Based on the sequence of CPB2, three siRNAs were designed and chemically synthesized, and then transfected into the breast cancer cell line MDA-MB-231 with lipofectamine 2000.  TAFI mRNA and protein levels were determined by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot.  Cell invasive and metastasis abilities and growth inhibition were determined by Transwell assay and MTT assay.  ResultssiRNAs targeting CPB2 significantly down -regulated mRNA and protein levels of TAFI (P<0.05), and the inhibition ratio ranged from 55.4% to 42.6%.  The growth of the breast cancer cell line MDA-MB-231 was inhibited in siRNA groups (P<0.05), and invasive and metastasis abilities were also significantly inhibited compared with the negative control group (P<0.05).  Conclusion    CPB2-siRNA can significantly down-regulate expression of TAFI in transcriptional and translational levels, and inhibits cell growth, invasion and metastasis ability of the breast cancer cell line MDA-MB-231.

Key words: Breast tumor； RNA interference； Thrombin activatable fibrinolysis inhibitor