TY - JOUR
T1 - Transition of human breast cancer cells from an oestrogen responsive to unresponsive state
AU - Darbre, Philippa D.
AU - Daly, Roger J.
PY - 1990/12/20
Y1 - 1990/12/20
N2 - An in vitro model system is described for studying the problem of loss of steroid sensitivity in breast cancer cells. Growth of cloned oestrogen-sensitive human breast cancer cells in the long-term absence of steroid gives rise to a population of oestrogen-insensitive cells. In ZR-75-1 cells, the effect is clonal but occurs at high frequency suggesting a mechanism affecting a wide proportion of the cell population synchronously. This does not involve any reduction in oestrogen receptor number. Furthermore, there is no coordinated loss of oestrogen-sensitive molecular markers, showing that oestrogen receptors remain not only present but functional. These growth changes are not accompanied by any loss of growth inhibition by antioestrogen. Although steroid deprivation does not result in loss of oestrogen-sensitive markers, this does not hold true for other steroids. There was a reduction in progestin, androgen and glucocorticoid regulation on transfected LTRs. Loss of steroid-sensitive growth was accompanied by changes in response to exogenous growth factors and altered endogenous growth factor mRNA production. Steroid-deprived T-47-D cells acquire sensitivity to stimulation by TGFβ and have raised TGFβ1 and TGFβ2 mRNA levels. ZR-75-1 cells are growth inhibited by TGFβ and have reduced TGFβ1mRNA levels. In MCF-7 cells, increased IGFII mRNA, following transfection, can result in an increased basal cell growth rate in the absence of steroid. These findings are discussed in relation to possible autocrine mechanisms in the loss of steroid sensitivity of breast cancer cells.
AB - An in vitro model system is described for studying the problem of loss of steroid sensitivity in breast cancer cells. Growth of cloned oestrogen-sensitive human breast cancer cells in the long-term absence of steroid gives rise to a population of oestrogen-insensitive cells. In ZR-75-1 cells, the effect is clonal but occurs at high frequency suggesting a mechanism affecting a wide proportion of the cell population synchronously. This does not involve any reduction in oestrogen receptor number. Furthermore, there is no coordinated loss of oestrogen-sensitive molecular markers, showing that oestrogen receptors remain not only present but functional. These growth changes are not accompanied by any loss of growth inhibition by antioestrogen. Although steroid deprivation does not result in loss of oestrogen-sensitive markers, this does not hold true for other steroids. There was a reduction in progestin, androgen and glucocorticoid regulation on transfected LTRs. Loss of steroid-sensitive growth was accompanied by changes in response to exogenous growth factors and altered endogenous growth factor mRNA production. Steroid-deprived T-47-D cells acquire sensitivity to stimulation by TGFβ and have raised TGFβ1 and TGFβ2 mRNA levels. ZR-75-1 cells are growth inhibited by TGFβ and have reduced TGFβ1mRNA levels. In MCF-7 cells, increased IGFII mRNA, following transfection, can result in an increased basal cell growth rate in the absence of steroid. These findings are discussed in relation to possible autocrine mechanisms in the loss of steroid sensitivity of breast cancer cells.
UR - http://www.scopus.com/inward/record.url?scp=0025613354&partnerID=8YFLogxK
U2 - 10.1016/0960-0760(90)90416-I
DO - 10.1016/0960-0760(90)90416-I
M3 - Article
C2 - 2285587
AN - SCOPUS:0025613354
VL - 37
SP - 753
EP - 763
JO - Journal of Steroid Biochemistry and Molecular Biology
JF - Journal of Steroid Biochemistry and Molecular Biology
SN - 0960-0760
IS - 6
ER -