title: Inhibitory effect of lead on tube formation by cultured human vascular endothelial cells.
abstract: The effect of lead acetate (Pb) on the formation of capillary-like structures (tube formation) by cultured human umbilical vascular endothelial cells (HUVECs) was examined. HUVECs were seeded on a gelled basement membrane matrix (Matrigel). Treatment of HUVECs with 0.3-30.0 microM Pb for 24 hours inhibited the tube formation dose-dependently. The length of tube formation decreased time-dependently with 3.0-10.0 microM Pb. To elucidate the main target factor of Pb for this inhibition, the effects of Pb on the activity of protein kinase C (PKC) and Matrigel were examined. The addition of beta-phorbol 12-myristate 13-acetate (PMA, 50 nM), an activator of PKC, and isoquinolinesulfonamide derivative (H-7, 30 microM), an inhibitor of PKC, showed an increase and decrease in the tube formation, respectively. However, the results of simultaneous addition of Pb and either PMA or H-7 to HUVECs indicated that PMA and H-7 acted not synergistically but additively. When PKC activities in HUVECs were measured by a colorimetric assay after treatments with 3.0-10.0 microM Pb for 24 hours, there was no significant change in PKC activity in the cells. The Pb-inhibition of tube formation was suggested to be independent of PKC activity. Pretreatment of Matrigel with 3.0-10.0 microM Pb for different periods decreased the tube formation dose- and time-dependently. These findings suggest that Pb can inhibit the tube formation by HUVECs dose- and time-dependently and that the inhibitory effect of Pb could be dependent on the degeneration of Matrigel, not on PKC activity.
authors.affiliation: Department of Dermatology, Shimane Medical University, Izumo, Japan.
authors.forename: D
authors.initials: D
authors.lastname: Ueda
authors.forename: T
authors.initials: T
authors.lastname: Kishimoto
authors.forename: S
authors.initials: S
authors.lastname: Dekio
authors.forename: M
authors.initials: M
authors.lastname: Tada
mesh_terms: D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000494:pharmacology; D002478:Cells, Cultured; D003094:Collagen / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000648:ultrastructure; D005109:Extracellular Matrix / Q000187:drug effects; D006801:Humans; D007797:Laminin / Q000187:drug effects; D007854:Lead / Q000633:toxicity*; D009942:Organometallic Compounds / Q000633:toxicity*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D011509:Proteoglycans / Q000187:drug effects; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014470:Umbilical Cord
chemical_list: D004338:Drug Combinations; D007797:Laminin; D009942:Organometallic Compounds; D011509:Proteoglycans; C059485:matrigel; D007854:Lead; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D003094:Collagen; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate; C008261:lead acetate