title: Effect of P2 receptor on the intracellular calcium increase by cancer cells in human umbilical vein endothelial cells.
abstract: One of the important functions of vascular endothelial cells is as a barrier between blood and vascular tissue. This led us to speculate that cancer cells affect endothelial cells during metastasis. In the present study, we investigated the influence of human fibrosarcoma cells (HT-1080) on human umbilical vein endothelial cells (HUVEC), particularly intracellular calcium ion levels ([Ca2+]i), which are known to be an important intracellular signal transduction factor. HUVEC were treated with a fluorescent marker, and the fluorescence intensity of [Ca2+]i was then measured by phase contrast microscopic imaging. Extracellular adenosine triphosphate (ATP) release was measured using the chemiluminescence of luciferin-luciferase and a photon counting imaging system. HT-1080 (5x10(4) cells per dish) was found to increase [Ca2+]i in HUVEC. This [Ca2+]i rise was significantly reduced by U-73122 (phospholipase C inhibitor, 1 microM) and thapsigargin (calcium pump inhibitor, 1 microM). Interestingly, the [Ca2+]i rise in HUVEC was also significantly reduced by pyridoxalphosphare-6-azophenyl-2', 4'-disulfonic acid, a P2Y receptor antagonist (100 microM) and apyrase, a nucleotidase inhibitor (2 U/ml). In addition, we observed ATP release from HT-1080. These results suggest that [Ca2+]i in HUVEC was increased through the phospholipase C-IP3 pathway via ATP release from cancer cells. We previously reported that extracellular ATP increased [Ca2+]i and enhanced macromolecular permeability via the P2Y receptor. In tumor metastasis, cancer cells may exploit these regulatory mechanisms in the endothelial cell layer.
authors.affiliation: Department of Pharmacology, School of Pharmacy and Pharmaceutical Sciences, Mukogawa Women's University, Nishinomiya, 663-8179, Japan.
authors.forename: Namie
authors.initials: N
authors.lastname: Nejime
authors.forename: Naoko
authors.initials: N
authors.lastname: Tanaka
authors.forename: Ryoko
authors.initials: R
authors.lastname: Yoshihara
authors.forename: Satomi
authors.initials: S
authors.lastname: Kagota
authors.forename: Noriko
authors.initials: N
authors.lastname: Yoshikawa
authors.forename: Kazuki
authors.initials: K
authors.lastname: Nakamura
authors.forename: Masaru
authors.initials: M
authors.lastname: Kunitomo
authors.forename: Michio
authors.initials: M
authors.lastname: Hashimoto
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Shinozuka
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D045744:Cell Line, Tumor; D042783:Endothelial Cells / Q000378:metabolism*; D005354:Fibrosarcoma / Q000378:metabolism*; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D009362:Neoplasm Metastasis / Q000473:pathology; D018048:Receptors, Purinergic P2 / Q000378:metabolism*; D010738:Type C Phospholipases / Q000378:metabolism; D014471:Umbilical Veins / Q000166:cytology
chemical_list: D018048:Receptors, Purinergic P2; D015544:Inositol 1,4,5-Trisphosphate; D000255:Adenosine Triphosphate; D010738:Type C Phospholipases; D002118:Calcium