Partially purified bacteriocin kills malignant cells by apoptosis: programmed cell death.
Bacterial proteins, partially purified bacteriocin (PPB), were investigated for their selective killing of malignant cells. It is shown here that upon PPB-cell interaction DNA fragmentation starts within one hour and peaks at 6 hrs. This process requires an on-going cellular metabolism. It is prevented by both actinomycin D, a DNA dependent RNA synthesis inhibitor, and cycloheximide, a protein synthesis inhibitor. We show here that the DNA fragmentation is triggered by PPB-cell membrane-receptor interaction which signals the activation of endogenous cellular endonucleases rather than actually penetrating the cell and interacting directly with the DNA, or serving as a nuclease itself. Thus, it is suggested that the cell death initiated by the lethal bacterial proteins, PPB, is a programmed, step-wise cell death involving apoptosis.
Farkas-Himsley
H
H
Departement of Microbiology, Faculty of Medicine, University of Toronto, Ontario, Canada.
Zhang
Y S
YS
Yuan
M
M
Musclow
C E
CE
D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D001430:Bacteriocins / Q000302:isolation & purification / Q000494:pharmacology*; D016923:Cell Death / Q000187:drug effects; D002852:Chromatography, Ion Exchange; D003513:Cycloheximide / Q000494:pharmacology; D004273:DNA, Neoplasm / Q000096:biosynthesis / Q000187:drug effects* / Q000302:isolation & purification; D003609:Dactinomycin / Q000494:pharmacology; D004926:Escherichia coli / Q000254:growth & development; D005354:Fibrosarcoma; D016650:Fluorescein-5-isothiocyanate; D051379:Mice; D013936:Thymidine / Q000378:metabolism; D014316:Tritium; D014407:Tumor Cells, Cultured
D000903:Antibiotics, Antineoplastic; D001430:Bacteriocins; D004273:DNA, Neoplasm; D014316:Tritium; D003609:Dactinomycin; D003513:Cycloheximide; D016650:Fluorescein-5-isothiocyanate; D013936:Thymidine