title: H3 histamine receptor-mediated activation of protein kinase Calpha inhibits the growth of cholangiocarcinoma in vitro and in vivo.
abstract: Histamine regulates functions via four receptors (HRH1, HRH2, HRH3, and HRH4). The d-myo-inositol 1,4,5-trisphosphate (IP(3))/Ca(2+)/protein kinase C (PKC)/mitogen-activated protein kinase pathway regulates cholangiocarcinoma growth. We evaluated the role of HRH3 in the regulation of cholangiocarcinoma growth. Expression of HRH3 in intrahepatic and extrahepatic cell lines, normal cholangiocytes, and human tissue arrays was measured. In Mz-ChA-1 cells stimulated with (R)-(alpha)-(-)-methylhistamine dihydrobromide (RAMH), we measured (a) cell growth, (b) IP(3) and cyclic AMP levels, and (c) phosphorylation of PKC and mitogen-activated protein kinase isoforms. Localization of PKCalpha was visualized by immunofluorescence in cell smears and immunoblotting for PKCalpha in cytosol and membrane fractions. Following knockdown of PKCalpha, Mz-ChA-1 cells were stimulated with RAMH before evaluating cell growth and extracellular signal-regulated kinase (ERK)-1/2 phosphorylation. In vivo experiments were done in BALB/c nude mice. Mice were treated with saline or RAMH for 44 days and tumor volume was measured. Tumors were excised and evaluated for proliferation, apoptosis, and expression of PKCalpha, vascular endothelial growth factor (VEGF)-A, VEGF-C, VEGF receptor 2, and VEGF receptor 3. HRH3 expression was found in all cells. RAMH inhibited the growth of cholangiocarcinoma cells. RAMH increased IP(3) levels and PKCalpha phosphorylation and decreased ERK1/2 phosphorylation. RAMH induced a shift in the localization of PKCalpha expression from the cytosolic domain into the membrane region of Mz-ChA-1 cells. Silencing of PKCalpha prevented RAMH inhibition of Mz-ChA-1 cell growth and ablated RAMH effects on ERK1/2 phosphorylation. In vivo, RAMH decreased tumor growth and expression of VEGF and its receptors; PKCalpha expression was increased. RAMH inhibits cholangiocarcinoma growth by PKCalpha-dependent ERK1/2 dephosphorylation. Modulation of PKCalpha by histamine receptors may be important in regulating cholangiocarcinoma growth.
authors.affiliation: Scott & White Digestive Disease Research Center, Texas A&M Health Science Center College of Medicine, Temple, TX 76504, USA. hfrancis@tamu.edu
authors.forename: Heather
authors.initials: H
authors.lastname: Francis
authors.forename: Paolo
authors.initials: P
authors.lastname: Onori
authors.forename: Eugenio
authors.initials: E
authors.lastname: Gaudio
authors.forename: Antonio
authors.initials: A
authors.lastname: Franchitto
authors.forename: Sharon
authors.initials: S
authors.lastname: DeMorrow
authors.forename: Julie
authors.initials: J
authors.lastname: Venter
authors.forename: Shelley
authors.initials: S
authors.lastname: Kopriva
authors.forename: Guido
authors.initials: G
authors.lastname: Carpino
authors.forename: Romina
authors.initials: R
authors.lastname: Mancinelli
authors.forename: Mellanie
authors.initials: M
authors.lastname: White
authors.forename: Fanyin
authors.initials: F
authors.lastname: Meng
authors.forename: Antonella
authors.initials: A
authors.lastname: Vetuschi
authors.forename: Roberta
authors.initials: R
authors.lastname: Sferra
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Alpini
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001650:Bile Duct Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D001653:Bile Ducts, Intrahepatic / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D045744:Cell Line, Tumor; D018281:Cholangiocarcinoma / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D004195:Disease Models, Animal; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D017442:Histamine Agonists / Q000494:pharmacology*; D006639:Histidine / Q000031:analogs & derivatives / Q000494:pharmacology; D006801:Humans; D008297:Male; D008761:Methylhistamines / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D048052:Mitogen-Activated Protein Kinase 3 / Q000187:drug effects / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D051571:Protein Kinase C-alpha / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D018100:Receptors, Histamine H3 / Q000187:drug effects* / Q000378:metabolism; D040262:Receptors, Vascular Endothelial Growth Factor / Q000187:drug effects / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D016896:Treatment Outcome; D042461:Vascular Endothelial Growth Factor A / Q000187:drug effects / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D017442:Histamine Agonists; D008761:Methylhistamines; D018100:Receptors, Histamine H3; D042461:Vascular Endothelial Growth Factor A; D006639:Histidine; D040262:Receptors, Vascular Endothelial Growth Factor; D051571:Protein Kinase C-alpha; D048052:Mitogen-Activated Protein Kinase 3