title: Bacillus thuringiensis parasporal proteins induce cell-cycle arrest and caspase-dependant apoptotic cell death in leukemic cells.
abstract: Bacillus thuringiensis (Bt) parasporal proteins with selective anticancer activity have recently garnered interest. This study determines the efficacy and mode of cell death of Bt 18 parasporal proteins against 3 leukemic cell lines (CEM-SS, CCRF-SB and CCRF-HSB-2).Cell-based biochemical analysis aimed to determine cell viability and the percentage of apoptotic cell death in treated cell lines; ultrastructural analysis to study apoptotic changes and Western blot to identify the parasporal proteins' binding site were performed. Bt 18 parasporal proteins moderately decreased viability of leukemic cells but not that of normal human T lymphocytes. Further purification of the proteins showed changes in inhibition selectivity. Phosphatidylserine externalization, active caspase-3, cell cycle, and ultrastructural analysis confirmed apoptotic activity and S-phase cell-cycle arrest. Western blot analysis demonstrated glyceraldehyde 3-phosphate dehydrogenase as a binding protein. We suggest that Bt 18 parasporal proteins inhibit leukemic cell viability by cell-cycle arrest and apoptosis and that glyceraldehyde 3-phosphate dehydrogenase binding initiates apoptosis.
authors.affiliation: Division of Human Biology, School of Medical and Health Sciences, International Medical University, Kuala Lumpur, Malaysia.
authors.forename: Kok-Keong
authors.initials: KK
authors.lastname: Chan
authors.forename: Rebecca Shin-Yee
authors.initials: RS
authors.lastname: Wong
authors.forename: Shar Mariam
authors.initials: SM
authors.lastname: Mohamed
authors.forename: Tengku Azmi Tengku
authors.initials: TA
authors.lastname: Ibrahim
authors.forename: Maha
authors.initials: M
authors.lastname: Abdullah
authors.forename: Vishna Devi
authors.initials: VD
authors.lastname: Nadarajah
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D001402:B-Lymphocytes / Q000187:drug effects / Q000473:pathology / Q000648:ultrastructure; D001413:Bacillus thuringiensis; D001426:Bacterial Proteins / Q000494:pharmacology*; D053148:Caspase 3 / Q000378:metabolism*; D053179:Caspase 7 / Q000378:metabolism*; D002453:Cell Cycle / Q000187:drug effects; D059447:Cell Cycle Checkpoints / Q000187:drug effects*; D002460:Cell Line; D004731:Endotoxins / Q000494:pharmacology; D006801:Humans; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000378:metabolism / Q000473:pathology*; D013601:T-Lymphocytes / Q000187:drug effects / Q000473:pathology / Q000648:ultrastructure
chemical_list: D001426:Bacterial Proteins; D004731:Endotoxins; C412914:parasporin; D053148:Caspase 3; D053179:Caspase 7