17 beta-hydroxysteroid dehydrogenase gene expression in human breast cancer cells: regulation of expression by a progestin.
The expression of the 17 beta-hydroxysteroid dehydrogenase (17-HSD) gene in a series of human breast cancer cell lines was studied by Northern blot hybridization with a cDNA probe and by a time-resolved immunofluorometric assay using polyclonal antibodies against the enzyme protein. The 17-HSD enzyme protein concentration was measured in the 800 x g cell extract. A high concentration was measured in the BT-20 cell line, corresponding to one-fourth of the average concentration in placental tissue. Western blot analysis indicated that the antigen corresponded to a single Mr 35,000 band. In 2 other cell lines (MDA-MB-361 and T-47D), the 17-HSD protein concentration was much lower, but still measurable, whereas in the remaining 5 cell lines (HBL-100, MCF-7, MDA-MB-231, MDA-MB-468, and ZR-75-1) it was below the detection limit of the assay. Treatment of the cells for 5 days with the synthetic progestin, ORG2058, resulted in an increase of the 17-HSD protein concentration only in the T-47D cell line. By Northern blot analysis, a low level of 2.3-kilobase mRNA transcripts was detected in all 8 cell lines. In addition, a 1.3-kilobase 17-HSD mRNA was present in the samples from the 3 cell lines containing measurable amounts of 17-HSD protein in the cell extract, and the band intensities were proportional to the amount of protein measured with the immunofluorometric assay. Only in the T-47D cell line did progestin treatment correspond to an increased amount of the 17-HSD 1.3-kilobase mRNA. These results suggest that the 1.3-kilobase mRNA for 17-HSD is the form most closely associated with protein expression and is also the only form responding to the progestin induction of the 17-HSD gene.
Poutanen
M
M
Department of Clinical Chemistry, University of Oulu, Finland.
Moncharmont
B
B
Vihko
R
R
D015067:17-Hydroxysteroid Dehydrogenases / Q000235:genetics* / Q000378:metabolism; D001943:Breast Neoplasms / Q000201:enzymology / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D007527:Isoenzymes / Q000235:genetics; D010920:Placenta / Q000201:enzymology; D011282:Pregnenediones / Q000494:pharmacology*; D045167:Progesterone Congeners / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D014407:Tumor Cells, Cultured
D007527:Isoenzymes; D011282:Pregnenediones; D045167:Progesterone Congeners; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C020175:16 alpha-ethyl-21-hydroxy-19-nor-4-pregnene-3,20-dione; D015067:17-Hydroxysteroid Dehydrogenases