title: Brevinin-2R(1) semi-selectively kills cancer cells by a distinct mechanism, which involves the lysosomal-mitochondrial death pathway.
abstract: Brevinin-2R is a novel non-hemolytic defensin that was isolated from the skin of the frog Rana ridibunda. It exhibits preferential cytotoxicity towards malignant cells, including Jurkat (T-cell leukemia), BJAB (B-cell lymphoma), HT29/219, SW742 (colon carcinomas), L929 (fibrosarcoma), MCF-7 (breast adenocarcinoma), A549 (lung carcinoma), as compared to primary cells including peripheral blood mononuclear cells (PBMC), T cells and human lung fibroblasts. Jurkat and MCF-7 cells overexpressing Bcl2, and L929 and MCF-7 over-expressing a dominant-negative mutant of a pro-apoptotic BNIP3 (DeltaTM-BNIP3) were largely resistant towards Brevinin-2R treatment. The decrease in mitochondrial membrane potential (DeltaPsim), or total cellular ATP levels, and increased reactive oxygen species (ROS) production, but not caspase activation or the release of apoptosis-inducing factor (AIF) or endonuclease G (Endo G), were early indicators of Brevinin-2R-triggered death. Brevinin-2R interacts with both early and late endosomes. Lysosomal membrane permeabilization inhibitors and inhibitors of cathepsin-B and cathepsin-L prevented Brevinin-2R-induced cell death. Autophagosomes have been detected upon Brevinin-2R treatment. Our results show that Brevinin-2R activates the lysosomalmitochondrial death pathway, and involves autophagy-like cell death.
authors.affiliation: Department of Biochemistry and Medical Genetics, Manitoba Institute of Cell Biology, Cancer Care Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Saeid
authors.initials: S
authors.lastname: Ghavami
authors.forename: Ahmad
authors.initials: A
authors.lastname: Asoodeh
authors.forename: Thomas
authors.initials: T
authors.lastname: Klonisch
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Halayko
authors.forename: Kamran
authors.initials: K
authors.lastname: Kadkhoda
authors.forename: Tadeusz J
authors.initials: TJ
authors.lastname: Kroczak
authors.forename: Spencer B
authors.initials: SB
authors.lastname: Gibson
authors.forename: Evan P
authors.initials: EP
authors.lastname: Booy
authors.forename: Hossein
authors.initials: H
authors.lastname: Naderi-Manesh
authors.forename: Marek
authors.initials: M
authors.lastname: Los
mesh_terms: D000255:Adenosine Triphosphate / Q000032:analysis / Q000378:metabolism; D029845:Amphibian Proteins / Q000494:pharmacology* / Q000633:toxicity; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000494:pharmacology* / Q000633:toxicity; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D023082:Defensins / Q000494:pharmacology* / Q000633:toxicity; D011992:Endosomes / Q000187:drug effects / Q000648:ultrastructure; D016650:Fluorescein-5-isothiocyanate / Q000378:metabolism; D005456:Fluorescent Dyes / Q000378:metabolism; D005562:Formazans / Q000378:metabolism; D019073:HT29 Cells; D006801:Humans; D019169:Jurkat Cells; D007739:L Cells; D008247:Lysosomes / Q000378:metabolism* / Q000648:ultrastructure; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D051379:Mice; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D017382:Reactive Oxygen Species / Q000378:metabolism; D013778:Tetrazolium Salts / Q000378:metabolism
chemical_list: D029845:Amphibian Proteins; D023181:Antimicrobial Cationic Peptides; D023082:Defensins; D005456:Fluorescent Dyes; D005562:Formazans; D017382:Reactive Oxygen Species; D013778:Tetrazolium Salts; C078414:brevinin-2, Rana; C079782:MTT formazan; D000255:Adenosine Triphosphate; D016650:Fluorescein-5-isothiocyanate