title: Pyrrolidine dithiocarbamate-induced apoptosis depends on cell type, density, and the presence of Cu(2+) and Zn(2+).
abstract: Pyrrolidine dithiocarbamate (PDTC) has been found to induce or inhibit apoptosis in different cell types. Here we show that PDTC dose-dependently reduced the viability of rat smooth muscle cells (rSMC), human fibroblasts, and endothelial cells at low but not at high cell density. Endothelial cells were least sensitive, fibroblasts showed a medium sensitivity, and rSMC showed a high sensitivity to PDTC-mediated cell death. An early reduction in the mitochondrial membrane potential indicated a rapid onset of apoptosis in rSMC. Apoptosis was further confirmed by annexin V staining and DNA fragmentation analysis. Gel shift analysis demonstrated increased nuclear factor (NF)-kappaB activity in high-density rSMC compared with low-density cells. NF-kappaB has recently been shown to regulate the induction of anti-apoptotic proteins. Although PDTC is widely used as an inhibitor for NF-kappaB and a radical scavenger, our data show that PDTC rather enhanced NF-kappaB activity and, alone or in combination with menadione, induced oxygen radical generation. Notably, PDTC failed to reduce rSMC viability in medium without Cu(2+) or Zn(2+), and addition of Cu(2+) or Zn(2+) resulted in a dose-dependent increase in PDTC-induced cell death. Addition of both Cu(2+) and Zn(2+) showed synergistic effects. Our results indicate that the induction of apoptosis by PDTC requires Cu(2+) and Zn(2+) and is dependent on cell type and density. Such differential effects may have implications for studies of PDTC as an anti-atherosclerotic or immunomodulatory drug.
authors.affiliation: Cardiovascular Research Unit, Karolinska Institute, Stockholm, Sweden. werl@klp.med.uni-muenchen.de
authors.forename: W
authors.initials: W
authors.lastname: Erl
authors.forename: C
authors.initials: C
authors.lastname: Weber
authors.forename: G K
authors.initials: GK
authors.lastname: Hansson
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D001011:Aorta; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003300:Copper / Q000494:pharmacology*; D019327:Copper Sulfate / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D006801:Humans; D007425:Intracellular Membranes / Q000187:drug effects / Q000502:physiology; D007700:Kinetics; D008297:Male; D008928:Mitochondria / Q000187:drug effects / Q000502:physiology*; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D011759:Pyrrolidines / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000502:physiology; D013859:Thiocarbamates / Q000494:pharmacology*; D014471:Umbilical Veins; D014812:Vitamin K / Q000494:pharmacology; D015032:Zinc / Q000494:pharmacology*; D019287:Zinc Sulfate / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D011759:Pyrrolidines; D017382:Reactive Oxygen Species; D013859:Thiocarbamates; D014812:Vitamin K; C020972:pyrrolidine dithiocarbamic acid; D019287:Zinc Sulfate; D003300:Copper; D015032:Zinc; D019327:Copper Sulfate