Effect of Notch-1 small interfering RNA on biological function of triple-negative breast cancer cell line MDA-MB-231

Abstract

Objective To investigate the role of Notch-1 signaling pathway in the growth of triplenegative breast cancer ( TNBC ) and the action mechanism.Methods Notch-1 small interfering RNA (siRNA) was transiently transfected into MDA-MB-231 cells to down-regulate the mRNA expression of Notch-1.The cell proliferation was assessed by methyl thiazol tetrazolium (MTT) assay during 5 days after transfection.And the changes in cell apoptosis and cell cycle were evaluated 48 h after transfection by flow cytometry.Real-time polymerase chain reaction (PCR) was used to detect the mRNA expression of Notch-1,Cyclin D1,bcl-2,bcl-XL and Western blotting was used to measure nuclear factor-κB (NF-κB) level in cell nucleus.Results Notch-1 siRNA could effectively inhibit the expression of Notch-1,with the inhibition rate being 88.6％.The proliferation of MDA-MB-231 cells was markedly inhibited by Notch-1 siRNA with the inhibition rate being 44.7％.The apoptosis rate was increased from 3.67％ to 13.25％ and the percentage of cells in G2 phase was increased from 6.27％ to 14.28％,respectively.Down-regulation of the expression of Notch-1 by siRNA could down-regulate the expression of NF-κB in nucleus,and the expression of Cyclin D1,bcl-2 and bcl-XL in MDA-MB-231 cells.Conclusion Our results suggest that Notch-1 pathway plays a critical role in TNBC.Down-regulation of Notch-1 by siRNA can inhibit the proliferation of MDA-MB-231 cells.Notch-1 may be a novel therapeutic target of TNBC. Key words: Triple-negative breast cancer; Notch-1 ; Nuclear factor-κB; RNA interference