title: Goniothalamin induces coronary artery smooth muscle cells apoptosis: the p53-dependent caspase-2 activation pathway.
abstract: Goniothalamin (GN), a styryl-lactone isolated from Goniothalamus andersonii, has been demonstrated to possess antirestenostic properties by inducing apoptosis on coronary artery smooth muscle cells (CASMCs). In this study, the molecular mechanisms of GN-induced CASMCs apoptosis were further elucidated. Apoptosis assessment based on the externalization of phosphatidylserine demonstrated that GN induces CASMCs apoptosis in a concentration-dependent manner. The GN-induced DNA damage occurred with concomitant elevation of p53 as early as 2 h, demonstrating an upstream signal for apoptosis. However, the p53 elevation in GN-treated CASMCs was independent of NAD(P)H: quinone oxidoreductase 1 and Mdm-2 expression. An increase in hydrogen peroxide and reduction in free thiols confirmed the role for oxidative stress in GN treatment. Pretreatment with the pan-caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone (z-VAD-FMK) that significantly abrogated GN-induced CASMCs apoptosis suggested the involvement of caspase(s). The role of apical caspase-2, -8, and -9 was then investigated, and sequential activation of caspase-2 and -9 but not caspase-8 leading to downstream caspase-3 cleavage was observed in GN-treated CASMCs. Reduction of ATP level and decrease in oxygen consumption further confirmed the role of mitochondria in GN-induced apoptosis in CASMCs. The mitochondrial release of cytochrome c was seen without mitochondrial membrane potential loss and was independent of cardiolipin. These data provide insight into the mechanisms of GN-induced apoptosis, which may have important implications in the development of drug-eluting stents.
authors.affiliation: Department of Biomedical Science, Faculty of Allied Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur 50300, Malaysia.
authors.forename: Kok Meng
authors.initials: KM
authors.lastname: Chan
authors.forename: Nor Fadilah
authors.initials: NF
authors.lastname: Rajab
authors.forename: David
authors.initials: D
authors.lastname: Siegel
authors.forename: Laily Bin
authors.initials: LB
authors.lastname: Din
authors.forename: David
authors.initials: D
authors.lastname: Ross
authors.forename: Salmaan Hussain
authors.initials: SH
authors.lastname: Inayat-Hussain
mesh_terms: D000255:Adenosine Triphosphate / Q000032:analysis; D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D053143:Caspase 2 / Q000378:metabolism*; D002478:Cells, Cultured; D045304:Cytochromes c / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects*; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects; D011753:Pyrones / Q000633:toxicity*; D013481:Superoxides / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000502:physiology*
chemical_list: D000590:Amino Acid Chloromethyl Ketones; D011753:Pyrones; D016159:Tumor Suppressor Protein p53; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D013481:Superoxides; C103280:goniothalamin; D000255:Adenosine Triphosphate; D045304:Cytochromes c; D006861:Hydrogen Peroxide; D016660:NAD(P)H Dehydrogenase (Quinone); C447479:NQO1 protein, human; D053143:Caspase 2