Proteasome inhibitors sensitize human vascular smooth muscle cells to Fas (CD95)-mediated death.
It was investigated whether proteasome activity was implicated in susceptibility of human vascular smooth muscle cells (VSMCs) to Fas-mediated death. Human fetal aorta smooth muscle cells were treated with agonistic anti-Fas antibody (CH11) and proteasome inhibitors (MG115 or MG132) and then cell death was determined by morphology, viability, and DNA fragmentation. The present study reports that: (a) crosslinking of Fas receptor with anti-Fas antibody in the presence of proteasome inhibitor-induced death and DNA degradation in human VSMCs that were blocked by caspases inhibitor z-DEVD.fmk; (b) cotreatment with anti-Fas antibody and proteasome inhibitor activated caspase-3; (c) proteasome inhibitors did not influence expression of procaspase-8, procaspase-3, c-FLIP, and Bcl-2; and (d) proteasome inhibitors up-regulated Fas and FADD. The data indicate that proteasome activity is important in survival of VSMCs and provide the first evidence that proteasome is involved in Fas signal transduction. The present study proposes novel mechanism(s) by which VSMCs become susceptible to FasL.
Kim
K
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Department of Pathology, University of Washington, Seattle, Washington 98195, USA. koanhoi@u.washington.edu
D000906:Antibodies / Q000494:pharmacology; D015153:Blotting, Western; D053148:Caspase 3; D020169:Caspases / Q000187:drug effects / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects; D016923:Cell Death / Q000187:drug effects*; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D003432:Cross-Linking Reagents / Q000494:pharmacology; D003546:Cysteine Endopeptidases / Q000378:metabolism; D004247:DNA / Q000187:drug effects / Q000378:metabolism; D053938:DNA Fragmentation / Q000187:drug effects; D006801:Humans; D007976:Leupeptins / Q000494:pharmacology; D009097:Multienzyme Complexes / Q000037:antagonists & inhibitors* / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D011480:Protease Inhibitors / Q000494:pharmacology*; D046988:Proteasome Endopeptidase Complex; D015398:Signal Transduction / Q000187:drug effects; D019014:fas Receptor / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism
D000906:Antibodies; D003432:Cross-Linking Reagents; D007976:Leupeptins; D009097:Multienzyme Complexes; D011480:Protease Inhibitors; C089486:carbobenzoxy-leucyl-leucyl-norvalinal; D019014:fas Receptor; D004247:DNA; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde