TY - JOUR
T1 - Irreversible loss of the oestrogen receptor in T47D breast cancer cells following prolonged oestrogen deprivation
AU - Pink, J. J.
AU - Bilimoria, M. M.
AU - Assikis, J.
AU - Jordan, V. C.
N1 - Funding Information:
This work was supported by NIH grant CA32713 to VCJ and JJP was supported in part by NIH training grant 5T32-CA09471. MMB and VJA were supported by generous training fellowships from the Lynn Sage Breast Cancer Foundation. We wish to thank Dr Alan Wakeling (Zeneca Pharmaceuticls) for the generous gifts
PY - 1996
Y1 - 1996
N2 - The development of antioestrogen resistance is a major clinical obstacle encountered in the treatment of breast cancer. By long-term growth in oestrogen-free medium, we have derived an oestrogen-independent, anti-oestrogen resistant cell line from the oestrogen receptor (ER)-positive, oestrogen-dependent T47D human breast cancer cell line. This cell line grows maximally in oestrogen-free medium and is resistant to all tested antioestrogens. This cell line does not express any measurable amounts of ER mRNA or protein and, in short-term studies, these cells show no response to either oestrogens or antioestrogens. However, return of these cells to oestrogen-containing medium for more than 8 weeks resulted in the re-expression of ER mRNA and protein. Subsequent limiting dilution subcloning of the T47D:C4 line revealed two phenotypically distinct clones, one which did not express measurable ER after long-term growth in oestrogen-containing medium and one which expressed ER mRNA and protein after a number of weeks in oestrogen-containing medium. In the absence of oestrogen, both types of cells are ER-negative as determined by Northern and Western blotting and lack of any oestrogen-dependent responses. The clone which re-expresses the ER (T47D:C4:5W) now responds to E2 With a 50% increase in growth and a 30-fold induction of an ER-reponsive luciferase reporter construct. Long-term growth of the stably ER-negative clone (T47D:C4:2W) causes no measurable oestrogen-mediated responses, as assessed by ER expression, growth stimulation or luciferase induction. Interestingly, ER mRNA can be detected in both cell types by using reverse transcriptase-polymerase chain reaction (RT-PCR). This suggests that the ER mRNA present in the T47D:C4:2W done is either inefficiently translated or is present at such a low level as to be functionally irrelevant. These novel clonal cell lines will prove to be invaluable in the study of the regulation of ER expression and regulatory pathways leading to oestrogen-independent growth.
AB - The development of antioestrogen resistance is a major clinical obstacle encountered in the treatment of breast cancer. By long-term growth in oestrogen-free medium, we have derived an oestrogen-independent, anti-oestrogen resistant cell line from the oestrogen receptor (ER)-positive, oestrogen-dependent T47D human breast cancer cell line. This cell line grows maximally in oestrogen-free medium and is resistant to all tested antioestrogens. This cell line does not express any measurable amounts of ER mRNA or protein and, in short-term studies, these cells show no response to either oestrogens or antioestrogens. However, return of these cells to oestrogen-containing medium for more than 8 weeks resulted in the re-expression of ER mRNA and protein. Subsequent limiting dilution subcloning of the T47D:C4 line revealed two phenotypically distinct clones, one which did not express measurable ER after long-term growth in oestrogen-containing medium and one which expressed ER mRNA and protein after a number of weeks in oestrogen-containing medium. In the absence of oestrogen, both types of cells are ER-negative as determined by Northern and Western blotting and lack of any oestrogen-dependent responses. The clone which re-expresses the ER (T47D:C4:5W) now responds to E2 With a 50% increase in growth and a 30-fold induction of an ER-reponsive luciferase reporter construct. Long-term growth of the stably ER-negative clone (T47D:C4:2W) causes no measurable oestrogen-mediated responses, as assessed by ER expression, growth stimulation or luciferase induction. Interestingly, ER mRNA can be detected in both cell types by using reverse transcriptase-polymerase chain reaction (RT-PCR). This suggests that the ER mRNA present in the T47D:C4:2W done is either inefficiently translated or is present at such a low level as to be functionally irrelevant. These novel clonal cell lines will prove to be invaluable in the study of the regulation of ER expression and regulatory pathways leading to oestrogen-independent growth.
KW - Antioestrogen resistance
KW - Breast cancer
KW - Oestrogen receptor
KW - Oestrogen-independent growth
KW - T47D
UR - http://www.scopus.com/inward/record.url?scp=0029844145&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0029844145&partnerID=8YFLogxK
U2 - 10.1038/bjc.1996.521
DO - 10.1038/bjc.1996.521
M3 - Article
C2 - 8883409
AN - SCOPUS:0029844145
SN - 0007-0920
VL - 74
SP - 1227
EP - 1236
JO - British journal of cancer
JF - British journal of cancer
IS - 8
ER -