Differential expression of estrogen receptor mRNA splice variants in the tamoxifen resistant human breast cancer cell line, MCF-7/TAMR-1 compared to the parental MCF-7 cell line.
Mol Cell Endocrinol
; 109(2): 197-207, 1995 Apr 01.
Article
em En
| MEDLINE
| ID: mdl-7664983
ABSTRACT
Breast cancer patients with an estrogen receptor (ER) positive tumor can be treated with the anti-estrogen tamoxifen, but development of anti-estrogen resistance is a serious problem. We have analyzed a tamoxifen resistant human breast cancer cell line MCF-7/TAMR-1 for alterations in ER which might explain the tamoxifen resistance. The MCF-7/TAMR-1 cells expressed both wild-type ER mRNA and protein, and by RT-PCR we were able to clone ER cDNAs corresponding to the following mRNA splice variants ER delta E2, ER delta E4, ER delta E5, ER delta E7 and a new double splice variant lacking both exon 4 and 7 (ER delta E4,7) The existence of the ER delta E4,7 variant was confirmed by RNase protection assay. Semi-quantitative RT-PCR revealed that ER delta E2 mRNA was expressed at a higher level in MCF-7/TAMR-1 cells, whereas the ER delta E5 mRNA was expressed at a significantly lower level in MCF-7/TAMR-1 cells compared with MCF-7 cells. The differential expression of the two ER mRNA splice variants indicates that they may be involved in anti-estrogen resistance, although the present knowledge of their biological function does not provide us with an explanation.
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Base de dados:
MEDLINE
Assunto principal:
Tamoxifeno
/
Neoplasias da Mama
/
RNA Mensageiro
/
Receptores de Estrogênio
/
Splicing de RNA
/
Proteínas de Neoplasias
Limite:
Humans
Idioma:
En
Ano de publicação:
1995
Tipo de documento:
Article