Fast, Stable Induction of P-Glycoprotein-mediated Drug Resistance in BT-474 Breast Cancer Cells by Stable Transfection of ABCB1 Gene

Abstract

Background: Patients with P-glycoprotein and HER2/neu (HER2) receptor-overexpressing breast cancer usually have poor clinical outcomes. However, there exist no commercially available breast cancer cell lines that are HER2/P-glycoprotein double-positive, which limits research in this field.

Materials and methods: We report on the development and characterization of a drug-resistant sub-line from an HER2-positive breast cancer cell line by stable transfection of the ATP-binding cassette (ABC) subfamily B member 1 (ABCB1) gene which encodes P-glycoprotein.

Results: ABCB1 gene expression levels were higher after transfection, which led to a 40-fold increase in P-glycoprotein expression. Interestingly, the transfection of ABCB1 also led to a slight increase in HER2 gene and protein expression levels. The transfection of ABCB1 increased the P-glycoprotein expression levels significantly.

Conclusion: The method used herein for developing this cell line is appropriate for fast, stable induction of P-glycoprotein-mediated drug resistance compared to traditional methods. The in vitro cytotoxicity test suggests this cell line has cross-resistance to a wide range of chemotherapeutic agents.

Keywords: BT-474; HER2; MDR; P-glycoprotein; breast cancer; transfection.