Targeted inhibition of Notch1 gene enhances the killing effects of paclitaxel on triple negative breast cancer cells.

OBJECTIVE

To study the influence of targeted inhibition of Notch1 gene on the killing effects of paclitaxel on triple negative breast cancer cells.

METHODS

The triple negative [estrogen receptor (ER)/progesterone receptor (PR)/human epidermal growth factor receptor 2 (Her2)] breast cancer cell line MDA-MB-231 and ER/PR/HER-2-positive breast cancer cell line MCF-7 were cultured, transfected with Notch1-siRNA-overexpression plasmid and blank plasmid, and treated with different concentrations of paclitaxel, and then the cell proliferation activity and apoptosis rate as well as the mRNA expression of Caspase-3, Caspase-9 and Bcl-2 were determined.

RESULTS

Paclitaxel could decrease the MDA-MB-231 and MCF-7 cell proliferation activity as well as Bcl-2 mRNA expression, and increase MDA-MB-231 and MCF-7 cell apoptosis rate as well as Caspase-3 and Caspase-9 mRNA expression in dose-dependent manners; with the same dose of paclitaxel treatment, the inhibitory effects on MDA-MB-231 cell proliferation activity and Bcl-2 mRNA expression as well as the promoting effects on MDA-MB-231 cell apoptosis and mRNA expression of Caspase-3 and Caspase-9 were weaker than those on MCF-7 cell; after 0.5 μM paclitaxel combined with Notch1-siRNA treatment, MDA-MB-231 cell proliferation activity and Bcl-2 mRNA expression were significantly lower than those after 0.5 μM paclitaxel combined with control plasmid treatment while cell apoptosis rate and mRNA expression of Caspase-3 and Caspase-9 were higher than those after 0.5 μM paclitaxel combined with control plasmid treatment.

CONCLUSIONS

Targeted inhibition of Notch1 gene may enhance the killing effects of paclitaxel on triple negative breast cancer cells by up-regulating the expression of Caspase-3 and Caspase-9 and inhibiting the expression of Bcl-2.