Regulation of SBP synthesis in human cancer cell lines by steroid and thyroid hormones.
The presence of human sex steroid binding protein (SBP) in liver cells, the supposed site of SBP synthesis, and in other target cells for sex steroid hormones such as breast, endometrium and prostate epithelium, have been demonstrated by indirect immunofluorescence. It is not known whether SBP enters endometrial and prostate cells by endocytosis, possibly mediated by a cell membrane receptor process, or if SBP is synthesized in these cells. SBP mRNA has been searched in human cancer cell lines originated from liver (Hep G2/H5A), breast (MCF-7), endometrium (RL95-2) and prostate (LNCaP). It was only found in hepatoma cells where it is regulated by estradiol, antiestrogen tamoxifen and triiodothyronine, in a similar way as secreted SBP. This work provides evidence that human SBP is synthesized in the liver, and it also suggests that its regulation may involve non-steroidal factors.
Mercier-Bodard
C
C
Lab. Hormones, INSERM U 33, Bicêtre, France.
Baville
F
F
Bideux
G
G
Binart
N
N
Chambraud
B
B
Baulieu
E E
EE
D015152:Blotting, Northern; D001943:Breast Neoplasms; D006528:Carcinoma, Hepatocellular; D002460:Cell Line; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D008113:Liver Neoplasms; D008297:Male; D009693:Nucleic Acid Hybridization; D011471:Prostatic Neoplasms; D012333:RNA, Messenger / Q000235:genetics; D012738:Sex Hormone-Binding Globulin / Q000096:biosynthesis / Q000235:genetics*; D013629:Tamoxifen / Q000494:pharmacology*; D014284:Triiodothyronine / Q000494:pharmacology*; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism*; D014594:Uterine Neoplasms
D012333:RNA, Messenger; D012738:Sex Hormone-Binding Globulin; D014284:Triiodothyronine; D013629:Tamoxifen; D004958:Estradiol