BAX and BAK proteins are required for cyclin-dependent kinase inhibitory drugs to cause apoptosis.
In previous reports, we have shown in SH-SY5 cells that olomoucine and roscovitine, two inhibitory drugs of cyclin-dependent kinases, caused apoptosis independent of the extrinsic pathway. In this experimental paradigm, apoptosis was refractory to the protective effects of either Bcl-2 or Bcl-XL overexpression. We are now reporting that the failure of Bcl-XL to prevent dell death was consistent with no effect on the kinetics of caspase activation and cytochrome c release. To further characterize this issue, we have discarded a direct effect of either olomoucine or roscovitine on mitochondrial permeability transition. Moreover, we have evidence that an intrinsic pathway took place in SH-SY5Y cells by showing the mitochondrial translocation of a GFP-Bax construct on transfection and treatment with cyclin-dependent kinase inhibitory drugs. Finally, we tested the effect of olomoucine and roscovitine on wild-type, bax-/-, bak-/-, and double bax-/-bak-/- mouse embryonic fibroblasts (MEF). In wild-type MEFs, both drugs induced cell death by apoptosis in a dose-dependent manner. In bax-/-, bak-/-, and, particularly, double bax-/-bak-/- MEFs, we observed the inhibition of apoptosis. In conclusion, olomoucine and roscovitine caused apoptosis through an intrinsic pathway, with Bax and Bak proteins being involved.
Garrofé-Ochoa
Xènia
X
Molecular Pharmacology Laboratory, Departament de Medicina Experimental, Universitat de Lleida, IRBLLEIDA, C/Montserrat Roig, 2 25008-Lleida, Catalonia, Spain.
Melero-Fernández de Mera
Raquel M
RM
Fernández-Gómez
Franciso J
FJ
Ribas
Judit
J
Jordán
Joaquín
J
Boix
Jacint
J
D000818:Animals; D017209:Apoptosis; D045744:Cell Line, Tumor; D018844:Cyclin-Dependent Kinases / Q000378:metabolism*; D045304:Cytochromes c / Q000378:metabolism; D006801:Humans; D051379:Mice; D008822:Mice, Transgenic; D008928:Mitochondria / Q000378:metabolism; D050998:bcl-2 Homologous Antagonist-Killer Protein / Q000378:metabolism / Q000502:physiology*; D051028:bcl-2-Associated X Protein / Q000378:metabolism / Q000502:physiology*; D051020:bcl-X Protein / Q000378:metabolism
C494772:BAK1 protein, human; C494826:BAX protein, human; C494811:BCL2L1 protein, human; C494773:Bak1 protein, mouse; C494827:Bax protein, mouse; C494812:Bcl2l1 protein, mouse; D050998:bcl-2 Homologous Antagonist-Killer Protein; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; D045304:Cytochromes c; D018844:Cyclin-Dependent Kinases