Modulation by oestrogen and progestins/antiprogestins of alpha interferon receptor expression in human breast cancer cells
Martin, J.H.; McKibben, B.M.; Lynch, M.; van den Berg, H.W.
European Journal of Cancer 27(2): 143-146
1991
ISSN/ISBN: 0959-8049 PMID: 1827277 Document Number: 368226
Human breast cancer ZR-75-1 cells, expressed 1516 (105) (mean [S.D.]) interferon (IFN) receptors (IFNR) per cell with Kd of 0.61 (0.15) nmol/l. Oestrogen independent ZR-PR-LT and tamoxifen resistant ZR-75-9a1 8 .mu.mol/l cells expressed similar numbers of IFNR. ZR-75-9a1 cells, which had been maintained in the absence of tamoxifen or known oestrogenic activity for 46 weeks, expressed a significantly higher number of IFNR (3170 [315]). Exposure of ZN-75-1 cells to 10-9 mol/l 17.beta.-oestradiol (E2) led to a consistent reduction in IFNR numbers whilst 10-6 mol/l tamoxifen slightly increased IFNR expression. Since IFN increases oestrogen receptors in this cell line, IFN and E2 appear to have opposite effects on expression of each others' receptor. 10-9 mol/l medroxy progestereon acetate and mifepristone significantly increased IFNR numbers whilst ORG 2058 decreased IFNR expression and ZK 98.299 had no effect. Progestin/antiprogestin induced IFNR increase in this cell line correlated with down-regulation of progesterone receptor (PR). HTus an IFN/ER/PR axis may exist in ZR-75-1 cells and variants.