We examined the role of multidrug resistance protein (MRP) 1 (ABCC1) in the emergence of mitoxantrone (MX) cross-resistance in a MCF7 breast cancer cell line selected for resistance to etoposide. The resistant cell line, MCF7/VP, expresses high levels of MRP1, whereas the parental cell line, MCF7/WT, does not. MCF7/VP cells are 6-10-fold cross-resistant to MX when compared with MCF7/WT cells. D...

To investigate the effects of the centrosomal protein, ninein-like protein (Nlp), on the proliferation, invasion and metastasis of MCF-7 breast cancer cells, the present study established green fluorescent protein (GFP)-containing MCF7 plasmids with steady and overexpression of Nlp (MCG7-GFP-N1p) and blank plasmids (MCF7-GFP) using lentiviral transfection technology in MCF7 the breast cancer ce...

The aim of the study was to investigate the effect of selected polyphenols: gallic acid (GA) and epigallocatechin gallate (EGCG) on matrix metalloproteinase (MMP-2 and MMP-9) activity in multidrug resistant (MDR) human breast adenocarcinoma cells: MCF7/DOX cells and obtained recently in our laboratory MCF7/DOX500 cells by the permanent selection of MCF7/DOX cells with 500 nM doxorubicin (DOX). ...

The development of resistance to the antiestrogen tamoxifen occurs in a high percentage of initially responsive patients. We have developed a new model in which to investigate acquired resistance to triphenylethylenes. A stepwise in vitro selection of the hormone-independent human breast cancer variant MCF-7/LCC1 against 4-hydroxytamoxifen produced a stable resistant population designated MCF7/...

A hormone-independent but hormone-responsive subpopulation (MCF7/MIII) of the hormone-dependent MCF-7 human breast cancer cell line (R. Clarke et al., Proc. Natl. Acad. Sci. USA 86: 3649-3653, 1989) was further passaged in ovariectomized nude mice and re-established in vitro as the continuous cell line MCF7/LCC1. The lag time to the appearance of proliferating tumors in ovariectomized animals i...

Accumulating evidence indicates that breast cancer is caused by cancer stem cells and cure of breast cancer requires eradication of breast cancer stem cells. Previous studies with leukemia stem cells have shown that NF-jB pathway is important for leukemia stem cell survival. In this study, by using MCF7 sphere cells as model of breast cancer stem-like cells, we evaluated the effect of NF-jB pat...

Overexpression of a novel oncogene MCT-1 (multiple copies in a T cell malignancy) causes malignant transformation of murine fibroblasts. To establish its role in the pathogenesis of breast cancer in humans, we generated stable transfectants of MCF7 breast cancer cells negative for endogenous MCT-1 (MCF7-MCT-1). Overexpression of MCT-1 in these cells resulted in a slight elevation of estrogen re...

Caspase-3 plays a critical role in a proteolytic cascade within the apoptosis signal pathway; this enzyme is commonly activated by numerous death signals and cleaves a variety of important cellular proteins. Using caspase-3-deficient MCF7 cells and clones stably transfected with the caspase-3 gene (MCF7/Casp3), we evaluated the role of caspase-3 in Bax-induced apoptosis. Bax overexpression indu...

A human breast cancer cell line (MCF7/WT) was selected for resistance to etoposide (VP-16) by stepwise exposure to 2-fold increasing concentrations of this agent. The resulting cell line (MCF7/VP) was 28-, 21-, and 9-fold resistant to VP-16, VM-26, and doxorubicin, respectively. MCF7/VP cells also exhibited low-level cross-resistance to 4'-(9-acridinylamino)methanesulfon-m-anisidide, mitoxantro...