title: Vascular endothelial growth factor stimulates endothelial colony forming cells proliferation and tubulogenesis by inducing oscillations in intracellular Ca2+ concentration.
abstract: Endothelial progenitor cells (EPCs) home from the bone marrow to the site of tissue regeneration and sustain neovascularization after acute vascular injury and upon the angiogenic switch in solid tumors. Therefore, they represent a suitable tool for cell-based therapy (CBT) in regenerative medicine and provide a novel promising target in the fight against cancer. Intracellular Ca(2+) signals regulate numerous endothelial functions, such as proliferation and tubulogenesis. The growth of endothelial colony forming cells (ECFCs), which are EPCs capable of acquiring a mature endothelial phenotype, is governed by store-dependent Ca(2+) entry (SOCE). This study aimed at investigating the nature and the role of VEGF-elicited Ca(2+) signals in ECFCs. VEGF induced asynchronous Ca(2+) oscillations, whose latency, amplitude, and frequency were correlated to the growth factor dose. Removal of external Ca(2+) (0Ca(2+)) and SOCE inhibition with N-(4-[3,5-bis(trifluoromethyl)-1H-pyrazol-1-yl]phenyl)-4-methyl-1,2,3-thiadiazole-5-carboxamide (BTP-2) reduced the duration of the oscillatory signal. Blockade of phospholipase C-γ with U73122, emptying the inositol-1,4,5-trisphosphate (InsP(3))-sensitive Ca(2+) pools with cyclopiazonic acid (CPA), and inhibition of InsP(3) receptors with 2-APB prevented the Ca(2+) response to VEGF. VEGF-induced ECFC proliferation and tubulogenesis were inhibited by the Ca(2+)-chelant, BAPTA, and BTP-2. NF-κB activation by VEGF was impaired by BAPTA, BTP-2, and its selective blocker, thymoquinone. Thymoquinone, in turn, suppressed VEGF-dependent ECFC proliferation and tubulogenesis. These data indicate that VEGF-induced Ca(2+) oscillations require the interplay between InsP(3)-dependent Ca(2+) release and SOCE, and promote ECFC growth and tubulogenesis by engaging NF-κB. This novel signaling pathway might be exploited to enhance the outcome of CBT and chemotherapy.
authors: Department of Physiology, University of Pavia, Pavia, Italy.
authors: Silvia
authors: S
authors: Dragoni
authors: Umberto
authors: U
authors: Laforenza
authors: Elisa
authors: E
authors: Bonetti
authors: Francesco
authors: F
authors: Lodola
authors: Cinzia
authors: C
authors: Bottino
authors: Roberto
authors: R
authors: Berra-Romani
authors: Giacomo
authors: G
authors: Carlo Bongio
authors: Maria Pia
authors: MP
authors: Cinelli
authors: Germano
authors: G
authors: Guerra
authors: Paolo
authors: P
authors: Pedrazzoli
authors: Vittorio
authors: V
authors: Rosti
authors: Franco
authors: F
authors: Tanzi
authors: Francesco
authors: F
authors: Moccia
mesh_terms: D000328:Adult; D000813:Anilides / Q000494:pharmacology; D016227:Benzoquinones / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D042783:Endothelial Cells / Q000166:cytology*; D004791:Enzyme Inhibitors; D006801:Humans; D015151:Immunoblotting; D007211:Indoles / Q000494:pharmacology; D016328:NF-kappa B / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism*; D013830:Thiadiazoles / Q000494:pharmacology; D042461:Vascular Endothelial Growth Factor A / Q000494:pharmacology*; D055815:Young Adult
chemical_list: C476308:4-methyl-4'-(3,5-bis(trifluoromethyl)-1H-pyrazol-1-yl)-1,2,3-thiadiazole-5-carboxanilide; D000813:Anilides; D016227:Benzoquinones; D004791:Enzyme Inhibitors; D007211:Indoles; D016328:NF-kappa B; D013830:Thiadiazoles; D042461:Vascular Endothelial Growth Factor A; D004533:Egtazic Acid; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; C003466:thymoquinone; D002118:Calcium; C000543:cyclopiazonic acid