Linked Life Data

18474684

Source:http://linkedlifedata.com/resource/pubmed/id/18474684

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2008-7-21
pubmed:abstractText
Previous studies have suggested that histamine (HA) acts as an autocrine growth factor. We have explored the modulation of cell proliferation by HA using McA-RH7777 hepatoma cells. High L-histidine decarboxylase (HDC) expression and HA synthesis were found in McA-RH7777 cells. Whereas extracellular HA reached submicromolar concentrations, intracellular levels were very low, indicating that HA was secreted by the cells. McA-RH7777 cells also express H3-receptor (H3R) transcripts and proteins. Reverse transcriptase-polymerase chain reaction analysis detected only transcripts for the long isoform. Immunocytochemistry performed with a selective H3R antibody showed that most cells were immunoreactive. H3R binding sites (Bmax approximately 30 fmol/mg protein) were identified when [125I] iodoproxyfan binding was displaced by the agonist imetit. High-affinity binding also occurred at cytochrome P450 enzymes. This binding was not inhibited by HA, H3R agonists, or by a nonimidazole H3R antagonist but was displaced by imidazole H3R antagonists or by ketoconazole, a imidazole-containing cytochrome inhibitor. HA inhibited proliferation of McA-RH7777 hepatoma cells. The absence of uptake system, its much higher potency at H3Rs, and its low intracellular levels suggested that HA interacted with H3Rs rather than cytochromes. In agreement, both imidazole H3R antagonists, a nonimidazole H3R antagonist, and the HDC inhibitor alpha-monofluoromethyl histidine increased cell proliferation (up to approximately 60%), revealing a H3R-mediated inhibition by endogenous HA. Moreover, exogenous HA inhibited the increase induced by alpha-FMH or H3R antagonists with a nanomolar potency. In conclusion, our findings show that HA regulates proliferation of McA-RH7777 hepatoma cells by interacting with autoinhibitory H3Rs.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
1521-0103
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
326
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
406-13
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Autoregulation of McA-RH7777 hepatoma cell proliferation by histamine H3 receptors.
pubmed:affiliation
Laboratoire de Neurobiologie et Pharmacologie Moléculaire, Centre de Psychiatrie et Neurosciences de l'INSERM, 2 ter rue d'Alésia, 75014 Paris, France.
pubmed:publicationType
Journal Article