Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0265264 (HOS)
 1,119 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

High specific activity estradiol labeled with iodine-125 was used to detect approximately 200 saturable, high-affinity (dissociation constant approximately equal to 1.0 nM) nuclear binding sites in rat (ROS 17/2.8) and human (HOS TE85) clonal osteoblast-like osteosarcoma cells. Of the steroids tested, only testosterone exhibited significant cross-reactivity with estrogen binding. RNA blot analysis with a complementary DNA probe to the human estrogen receptor revealed putative receptor transcripts of 6 to 6.2 kilobases in both rat and human osteosarcoma cells. Type I procollagen and transforming growth factor-beta messenger RNA levels were enhanced in cultured human osteoblast-like cells treated with 1 nM estradiol. Thus, estrogen can act directly on osteoblasts by a receptor-mediated mechanism and thereby modulate the extracellular matrix and other proteins involved in the maintenance of skeletal mineralization and remodeling.
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PMID:Estrogen binding, receptor mRNA, and biologic response in osteoblast-like osteosarcoma cells. 316 26

Dual fluoroimmunohistochemical staining of estrogen receptor (ER) and bromodeoxyuridine was performed in a human osteoblastic osteosarcoma cell line, HOS TE85 cells. ER immunoreactivity was observed preferentially in the nuclei of the cells that were bromodeoxyuridine positive. ER expression at various phases of the cell cycle was investigated in HOS TE85 cells, which were synchronized at the G1/S phase boundary by intermittent exposure to thymidine and hydroxyurea. ER immunoreactivity became detectable in the S phase, decreased in the G2/M and G1 phases, and then reappeared in the S phase of the next cell cycle. Western blot analysis also showed that ER protein exists in these cells and increases in the S phase. Moreover, Northern blot analysis demonstrated that the expression of ER messenger RNA increases in the early S phase, gradually decreases during the progress of the cell cycle, and increases again in the S phase of the subsequent cell cycle. Interestingly, 17 beta-estradiol (10(-8) M) increased cell number and [3H]thymidine incorporation into DNA in the synchronized HOS TE85 cells, whereas this effect was not observed in the nonsynchronized HOS TE85 cells. The present studies suggest that the cell cycle-dependent regulation may contribute to the heterogeneity of ER expression in osteoblastic cells.
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PMID:Cell cycle-dependent expression of estrogen receptor and effect of estrogen on proliferation of synchronized human osteoblast-like osteosarcoma cells. 803 27

Expression of estrogen receptor (ER) was studied in MC3T3-E1 cells (mouse osteoblastic cell line), HOS TE85 cells (human osteosarcoma cell line), and primary osteoblastic cells derived from mouse calvaria with immunohistochemical techniques. The staining of ER was readily detectable in MC3T3-E1 cells, HOS TE85 cells, and primary osteoblastic cells by using a monoclonal anti-ER antibody that recognizes the DNA binding domain of ER. The immunoreactivity was distributed in the cytoplasm as well as in the nuclei. 17 beta-Estradiol (10(-8) M) did not alter this staining pattern. The expression of ER was confirmed by Northern blot analysis using rat ER cDNA probe, which revealed a 6.5 kb band in MC3T3-E1 cells and a 6.2 kb band in HOS TE85 cells. The mRNA level of ER was not altered by 17 beta-estradiol (10(-8) M). The immunohistochemical studies showed that ER was not detectable in all cells but in a small population of each cell type. This study is the first report to demonstrate the presence of ER immunohistochemically, and our results suggest the heterogeneity of ER expression among osteoblastic cells.
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PMID:Immunohistochemical detection and northern blot analysis of estrogen receptor in osteoblastic cells. 823 80

To investigate the functional differences between estrogen receptor (ER) alpha and beta subtypes, we studied the expression and the transcription stimulating activities of these receptors. RT-PCR has demonstrated that ER alpha is expressed at a high level in MCF-7 cells derived from human breast cancer. Both ER alpha and ER beta were expressed at a lower level in HOS-TE85 and Saos2 cells derived from human osteosarcoma. Chloramphenicol acetyltransferase reporter assay detected the transcriptional activation by the endogenous receptor only in MCF-7 cells. Agonistic effect of tamoxifen was observed as strong as that of 17beta-estradiol on ERE activation in MCF-7 cells at the concentration of 10(-7) M when ERE-containing reporter is constructed with beta-globin promoter. The effect of tamoxifen was not apparent when the reporter was constructed with thymidine kinase promoter, suggesting that the differential gene activation between tamoxifen and estrogen may take place depending upon ERE-promoter context. Agonistic activity of tamoxifen was also detected in COS-7 and Saos-2 cells, but not in HEC-1 cells derived from human endometrial carcinoma via exogenously expressed ER. Interestingly, this effect was ER alpha specific. Thus, we demonstrate that agonistic effect of tamoxifen depends on the cell type, ERE-promoter context, and ER subtype. These parameters would explain at least a part of the tissue specific effects of antiestrogens in vivo.
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PMID:Agonistic effect of tamoxifen is dependent on cell type, ERE-promoter context, and estrogen receptor subtype: functional difference between estrogen receptors alpha and beta. 922 41

We have identified and characterized a novel human estrogen receptor (ER) beta isoform, ERbetacx, which is truncated at the C-terminal region but has an extra 26 amino acids due to alternative splicing. The ERbetacx transcript is expressed in testis, ovary, thymus and prostate as well as in human cultured cell lines such as HEC-1, HOS-TE85 and Saos-2 cells. ERbetacx protein is also immunodetectable in these human cells. Biochemical analysis reveals that the average dissociation constants ( K d) of ERalpha and ERbeta for 17beta-estradiol (E2) are 0.2 and 0.6 nM respectively, but ERbetacx has no ligand binding ability. ERalpha and ERbeta proteins bind to the estrogen response element, whereas ERbetacx does not form any shifted complex in gel shift assays. In a transient expression assay, ERbetacx shows no ligand-dependent transactivation ability of a basal promoter and also cannot interact with a cofactor, TIF1alpha, in the presence or absence of E2. ERbetacx preferentially forms a heterodimer with ERalpha rather than that with ERbeta, inhibiting DNA binding by ERalpha. Interestingly, however, it shows a significant dominant negative activity only against ERalpha transactivation. Thus, this study indicates that ERbetacx potentially inhibits ERalpha-mediated estrogen action and that alternative splicing of the C-terminal region and its inhibitory properties are characteristic of several members of nuclear receptor isoforms.
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PMID:Molecular cloning and characterization of human estrogen receptor betacx: a potential inhibitor ofestrogen action in human. 967 11