Mechanism of action for N-substituted benzamide-induced apoptosis.
We have analysed the mechanism of action for induction of apoptosis by N-substituted benzamides using declopramide as a lead compound. We show here that declopramide at doses above 250 microM in the mouse 70Z/3 pre-B cell line or in the human promyeolocytic cancer cell line HL60 induced cytochrome c release into the cytosol and caspase-9 activation. The broad spectrum caspase inhibitor zVADfmk and caspase-9 inhibitor zLEDHfmk inhibited apoptosis and improved cell viability when administrated to cells 1 h before exposure to declopramide, whereas the caspase-8 inhibitor zIEDHfmk had less effect. Also, the over expression of Bcl-2 by transfection in 70Z/3 cells inhibited declopramide-induced apoptosis. Prior to the induction of apoptosis, a G(2)/M cell cycle block was induced by declopramide. The cell cycle block was also observed in the presence of broad spectrum caspase inhibitor zVADfmk and in a transfectant expressing high levels of Bcl-2. Furthermore, while p53 was induced in 70Z/3 cells by declopramide, neither the apoptotic mechanism nor the G(2)/M cell cycle block were dependent on p53 activation since both effects were also seen in p53 deficient HL60 cells after addition of declopramide.
Olsson
A R
AR
Section for Immunology, Department of Cell and Molecular Biology, BMC I:13, S-221 84, Lund, Sweden. anders.olsson@immuno.lu.se
Lindgren
H
H
Pero
R W
RW
Leanderson
T
T
D017209:Apoptosis / Q000187:drug effects*; D001549:Benzamides / Q000494:pharmacology*; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D003574:Cytochrome c Group / Q000378:metabolism; D004789:Enzyme Activation; D016195:G2 Phase / Q000187:drug effects; D018922:HL-60 Cells; D006801:Humans; D008787:Metoclopramide / Q000494:pharmacology; D008938:Mitosis / Q000187:drug effects; D011342:Procainamide / Q000031:analogs & derivatives* / Q000494:pharmacology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000502:physiology; D016159:Tumor Suppressor Protein p53 / Q000502:physiology
D001549:Benzamides; D003574:Cytochrome c Group; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; C037689:benzamide; C072799:declopramide; C506433:CASP9 protein, human; C506434:Casp9 protein, mouse; D053453:Caspase 9; D020169:Caspases; D011342:Procainamide; D008787:Metoclopramide