Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P04155 (pS2)
 1,234 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To examine the role of the estrogen response element (ERE) sequence in binding of liganded estrogen receptor (ER) to promoters, we analyzed in vivo interaction of liganded ER with the imperfect ERE in the pS2 gene and the composite estrogen-responsive unit (ERU) in the proteinase inhibitor 9 (PI-9) gene. In transient transfections of ER-positive HepG2-ER7 cells, PI-9 was strongly induced by estrogen, moxestrol (MOX), and 4-hydroxytamoxifen (OHT). PI-9 was not induced by raloxifene or ICI 182,780. Quantitative reverse transcriptase-PCR showed that moxestrol strongly induced cellular PI-9 and pS2 mRNAs, whereas OHT moderately induced PI-9 mRNA and weakly induced pS2 mRNA. Chromatin immunoprecipitation experiments demonstrated strong and similar association of 17beta-estradiol-hERalpha and MOX-hERalpha with the PI-9 ERU and with the pS2 ERE. Binding of MOX-hERalpha to the PI-9 ERU and the pS2 ERE was rapid and continuous. Although MOX-hERalpha bound strongly to the PI-9 ERU and less well to the pS2 ERE in chromatin immunoprecipitation, gel shift assays showed that estrogen-hERalpha binds with higher affinity to the deproteinized pS2 ERE than to the PI-9 ERU. Across a broad range of OHT concentrations, OHT-hERalpha associated strongly with the pS2 ERE and weakly with the PI-9 ERU. ICI-hERalpha bound poorly to the PI-9 ERU and effectively to the pS2 ERE. Raloxifene-hERalpha and MOX-hERalpha exhibited similar binding to the PI-9 ERU and the pS2 ERE. These studies demonstrate that ER ligand and ERE sequence work together to regulate in vivo binding of ER to estrogen-responsive promoters.
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PMID:Interplay between estrogen response element sequence and ligands controls in vivo binding of estrogen receptor to regulated genes. 1461 32

Breast cancer, the most frequent cancer in women, is the second leading cause of cancer-related death. Estrogens and estrogen receptors are well recognized to play predominant roles in breast cancer development and growth. Neo-tanshinlactone is a natural product isolated from Salvia miltiorrhiza and showed selective growth inhibition of ER+ breast cancer cell lines as demonstrated by cell proliferation assay and colony formation assay. The selective anti-proliferative effect of neo-tanshinlactone was associated with the induction of apoptosis in ER+ breast cancer cells. We also found that neo-tanshinlactone decreased steady state ESR1 mRNA levels in ER+ breast cancer cells, which was further confirmed by analysis of ER protein levels as well as the mRNA levels of target genes of this transcription factor, such as ESR2, BRCA1, CCND1, GREB1, TFF1, SERPINB9 and ABCA3. Furthermore, analysis of heterogeneous nuclear RNA (hnRNA) demonstrated that neo-tanshinlactone inhibited ESR1 mRNA de novo synthesis. The decrease of steady state ESR1 mRNA upon neo-tanshinlactone treatment was not abolished by protein synthesis inhibitor cycloheximide. And inhibition of mRNA synthesis with actinomycin D revealed no significant effect of neo-tanshinlactone on ESR1 mRNA stability. These results indicated that transcriptional down-regulation of ESR1 mRNA could contribute to the selective activity of neo-tanshinlactone on ER+ breast cancer cells. And as expected, the combination of neo-tanshinlactone and antiestrogen reagent tamoxifen showed a synergistic effect on growth of ER+ MCF7 cells. Our results suggest that neo-tanshinlactone is a promising regimen for ER+ breast tumors.
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PMID:Neo-tanshinlactone selectively inhibits the proliferation of estrogen receptor positive breast cancer cells through transcriptional down-regulation of estrogen receptor alpha. 2749 59