Progesterone receptors are expressed in human osteoblast-like cell lines and in primary human osteoblast cultures.
Expression of progesterone receptors (PR) was studied in human osteoblast-like cell lines and primary human osteoblast cultures at the molecular level. Using the sensitive reverse transcriptase polymerase chain reaction (RT-PCR) and oligonucleotide primers which flank the progesterone-binding domain of human PR, progesterone receptor (PR) mRNA was detected in three osteoblast-like cell lines--HOS-TE85, MG-63, and SAOS-2. When compared with beta-actin gene expression, levels of PRmRNA transcripts varied between cell lines (PRmRNA in HOS-TE85 > MG-63 >> SAOS-2). In addition, RT-PCR confirmed the presence of PRmRNA transcripts in primary human osteoblast cells cultured from collagenase-treated bone. Immunostaining was used to visualize PR protein in cells. All osteoblast-like cell lines showed specific staining for PR. Immunoreactivity was distributed equally in the nucleus and cytoplasm. The level of staining was significantly lower than that detected in PR-positive MCF-7 breast cancer cells though well above background levels obtained for PR-negative HeLa cells. The finding that PR is expressed at both the level of mRNA and protein in several osteoblast-like cell lines as well as in human primary osteoblast cultures indicates that bone-forming osteoblast cells are direct targets for progesterone action.
MacNamara
P
P
Department of Biochemistry, University College Galway, Ireland.
O'Shaughnessy
C
C
Manduca
P
P
Loughrey
H C
HC
D000328:Adult; D000368:Aged; D001483:Base Sequence; D002460:Cell Line; D002478:Cells, Cultured; D017931:DNA Primers; D005260:Female; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D011980:Receptors, Progesterone / Q000096:biosynthesis* / Q000235:genetics; D014407:Tumor Cells, Cultured
D017931:DNA Primers; D012333:RNA, Messenger; D011980:Receptors, Progesterone