Tunicamycin inhibits capillary endothelial cell proliferation by inducing apoptosis. Targeting dolichol-pathway for generation of new anti-angiogenic therapeutics.
Bovine adrenal medulla microvascular endothelial cells used in this study undergo cellular proliferation and differentiation upon culturing in vitro as observed both by light and scanning electron microscopy. Cells also respond to the growth promoting activity of serum and basic fibroblast growth factor (FGF2). Flow cytometric analysis of a synchronized culture established that cells take 68 hours to complete one cell cycle spending 36 hours in the G1 phase, 8 hours in the S phase, and 24 hours in the G2 + M phase when cultured in EMEM containing 2% heat-inactivated fetal bovine serum (FBS). At 10% serum, or in the presence of FGF2 (10 ng/ml-100 ng/ml) length of the cell cycle is reduced to 56 hours due to shortening of the G1 phase by 12 hours. Tunicamycin (a glucosamine-containing pyrimidine nucleotide), and an inhibitor of glucosaminyl-1-phosphate (GlcNAc 1-P) transferase, the first step of Glc3Man9GlcNAc2-PP-Dol (OSL) biosynthesis is found to inhibit the endothelial cells proliferation by inducing apoptosis as observed by flow cytometry and DNA laddering. Cell shrinkage, compaction of nuclei, membrane fragmentation, etc., typical of apoptotic response are frequently seen by light microscopy in the presence of tunicamycin. Scanning electron microscopy also exhibited a considerable amount of cell surface blebbing. Accumulation of an immunopositive cell specific asparagine-linked (N-linked) glycoprotein, Factor VIII:C in the absence of Glc3Man9GlcNAc2-PP-Dol in tunicamycin treated cells has been proposed as an apoptotic triggering mechanism under the current experimental conditions.
Martínez
J A
JA
Department of Biochemistry, School of Medicine, University of Puerto Rico, San Juan 00936-5067, USA.
Torres-Negrón
I
I
Amigó
L A
LA
Roldán
R A
RA
Mendéz
A
A
Banerjee
D K
DK
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001216:Asparagine / Q000378:metabolism; D002196:Capillaries / Q000166:cytology; D002417:Cattle; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D002999:Clone Cells; D004730:Endothelium, Vascular / Q000166:cytology*; D005169:Factor VIII / Q000378:metabolism; D006023:Glycoproteins / Q000378:metabolism; D008364:Mannosyltransferases / Q000378:metabolism*; D009389:Neovascularization, Pathologic / Q000378:metabolism*; D011105:Polyisoprenyl Phosphate Sugars / Q000096:biosynthesis*; D014415:Tunicamycin / Q000378:metabolism / Q000494:pharmacology*
C066723:Glc(3)Man(9)(GlcNAc)(2)-diphosphate-dolichol; D006023:Glycoproteins; D011105:Polyisoprenyl Phosphate Sugars; D014415:Tunicamycin; D001216:Asparagine; D005169:Factor VIII; D008364:Mannosyltransferases; C022755:dolichyl-phosphate beta-D-mannosyltransferase