title: Up-regulation of clusterin during phthalocyanine 4 photodynamic therapy-mediated apoptosis of tumor cells and ablation of mouse skin tumors.
abstract: Photodynamic therapy (PDT) using the silicon phthalocyanine photo-sensitizer Pc 4 is an oxidative stress associated with the induction of apoptosis in many cancer cells in vitro and in vivo. The mechanisms of PDT-induced tumor cell killing leading to apoptosis are incompletely understood. Clusterin, a widely expressed glycoprotein, is induced in tissues regressing as a consequence of oxidative stress-mediated cell death. Treatment of apoptosis-sensitive human epidermoid carcinoma cells (A431) with PDT resulted in significant up-regulation of clusterin with a maximum at 12 h after treatment, whereas clusterin levels in Pc 4-PDT-treated, apoptosis-resistant, radiation-induced fibrosarcoma (RIF-1) cells remained unchanged. The i.v. administration of Pc 4 to mice bearing chemically or UVB radiation-induced skin papillomas, followed by light application, led to increased clusterin protein expression, peaking 24 h after the treatment, when tumor regression was apparently visible. These data, for the first time, demonstrate the involvement of clusterin in PDT-mediated cell death and during tumor regression. This may have relevance in improving the efficacy of PDT using pharmacological inducers of clusterin.
authors.affiliation: Department of Dermatology, Case Western Reserve University, Cleveland, Ohio 44106, USA.
authors.forename: K
authors.initials: K
authors.lastname: Kalka
authors.forename: N
authors.initials: N
authors.lastname: Ahmad
authors.forename: T
authors.initials: T
authors.lastname: Criswell
authors.forename: D
authors.initials: D
authors.lastname: Boothman
authors.forename: H
authors.initials: H
authors.lastname: Mukhtar
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D051152:Clusterin; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006023:Glycoproteins / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D007211:Indoles / Q000494:pharmacology*; D051379:Mice; D008812:Mice, Hairless; D018632:Mice, Inbred SENCAR; D018832:Molecular Chaperones; D010212:Papilloma / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000494:pharmacology*; D012878:Skin Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D014407:Tumor Cells, Cultured; D015854:Up-Regulation / Q000187:drug effects
chemical_list: C495242:CLU protein, human; C495243:Clu protein, mouse; D051152:Clusterin; D006023:Glycoproteins; D007211:Indoles; D018832:Molecular Chaperones; D017319:Photosensitizing Agents; C107448:phthalocyanine Pc 4