Effects of steroid-free fetal serum and steroid supplementation on MUC1 gene expression in human breast cancer cell line MCF7.
MUC1 is a gene expressed by many normal epithelial tissues and aberrantly expressed by carcinomas. Studies regarding the expression of MUC1 in endometrial tissues and the constitution of its promoter region suggest a possible role for hormonal regulation of this gene. The aim of the present work was to evaluate the regulation of MUC 1 expression by 17 beta-estradiol (E2), progesterone (Pg) and by steroid-free fetal calf serum (FCS) in the hormone-sensitive cell line MCF7. MUC1 mRNA proved to be detectable by means of Northern-blot analysis in MCF7 cells, and its levels were strongly increased in cells grown with 10% steroid-free FCS. By contrast, the steady-state MUC1 mRNA levels of steroid-supplemented cells did not change compared to those of unsupplemented cells (controls). In conclusion, MUC1 expression is regulated by substances present in the steroid-stripped FCS (growth factors, e.g. Insulin-like Growth Factor). The lack of any observed MUC1 modulation by steroids could be due to: a) a low FCS concentration preventing the manifestation (permissive action) of possible gene regulation; b) an immediate stimulatory effect occuring in the first phases of the treatment, which could subsequently be lost.
Botti
C
C
Nuclear Medicine Department, Istituto Nazionale Tumori, Milano, Italy.
Seregni
E
E
Lombardo
C
C
Massaron
S
S
Bombardieri
E
E
D001943:Breast Neoplasms / Q000378:metabolism*; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D005312:Fetal Blood / Q000502:physiology*; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D018396:Mucin-1 / Q000235:genetics*; D011374:Progesterone / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D018396:Mucin-1; D011374:Progesterone; D004958:Estradiol