PURPOSE Mammary epithelial cells and the majority of breast cancer tumors require estrogen for continued growth. Antiestrogen therapy alone, or in combination with other drugs, has long been a common procedure for breast cancer treatment and prophylaxis. Thus, there is a critical need to elucidate the mechanism(s) of action of antiestrogen treatment, especially for patients who are at risk of b...

Emergence of antiestrogen-resistant cells in MCF-7 cells during suppression of estrogen signaling is a widely accepted model of acquired breast cancer resistance to endocrine therapy. To obtain insight into the genomic basis of endocrine therapy resistance, we characterized MCF-7 monoclonal sublines that survived 21-day exposure to tamoxifen (T-series sublines) or fulvestrant (F-series sublines...

BACKGROUND Estrogen receptors (ER) have important physiological roles in both the female and male reproductive systems. Previous studies using the estrogen receptor-alpha knockout mouse (alphaERKO) or antiestrogen treatment in adult rodents have shown that ERalpha is essential for normal function of the male reproductive tract. In the present study, time-response effects of the antiestrogen ICI...

The neuropeptide Y (NPY) Y(1) receptor (Y(1)R) has been suggested as a tumor marker for in vivo imaging and as a therapeutic target. In view of the assumed link between estrogen receptor (ER) and Y(1)R in mammary carcinoma and with respect to the development of new diagnostic tools, we investigated the Y(1)R protein expression in human MCF-7 cell variants differing in ER content and sensitivity...

The status of the 66-kDa human estrogen receptor(hER66) is a critical determinant in the assessment of the prognosis and in the design of treatment strategies of human breast cancer. Recently, we cloned the cDNA of an alternatively spliced variant of hER66, termed hER36; the predicted protein lacks both transcriptional activation domains of hER66 but retains its DNA-binding domain, partial dime...

Objective: To investigate the antineoplastic potential of a novel antiestrogen (AE) centchroman (CENT) using cell morphology, viability and cathepsin-D (Cath-D) gene expression as indices in MCF-7 human breast cancer cell line. Material and Methods: MCF-7 cells were incubated with CENT (1 μM, 10 μM) in the absence and presence of 17-β estradiol (E 2 , 10 nM) for 4 days. Investigations were carr...

Antiestrogen resistance often develops with prolonged exposure to hormone therapies, including tamoxifen, and is a major problem in the treatment of breast cancer. Understanding the mechanisms involved in the development of antiestrogen resistance is an important step in the development of new targeted therapies. Two forms of antiestrogen resistance exist: de novo resistance and acquired resist...

Antiestrogens are useful in the treatment of endocrine-respon sive breast cancers in humans. In an attempt to understand the mechanisms underlying their estrogen antagonism and antitumor character, we have examined the interaction of antiestrogens with three human breast cancer cell lines that differ markedly in their estrogen receptor content and in their sensitivity to growth suppression by a...