[Diamide and cyclosporin A enhanced arsenic trioxide-induced apoptosis in NB4 cells]
Yun Yu1, Peimin Jia, Ying Huang
1Shanghai Institute of Hematology, Rui-Jin Hospital, Shanghai Second Medical University, Shanghai 200025, China.
Objective:
To investigate the effects of mitochondrial membrane permeability transition pore (MPT)-opened agent diamide and MPT-closed agent cyclosporin A on arsenic trioxide (As(2)O(3))-induced apoptosis in acute promyelocytic leukemia (APL) cell line NB4.
Methods:
NB4 cells were treated with As(2)O(3) alone or in combination with diamide or cyclosporin A in different concentrations. Cell apoptosis was assessed by the morphological observation, Annexin-V assay, distribution of cellular DNA contents and genomic DNA electrophoresis. The mitochondrial transmembrane potentials (DeltaPsim) were detected by flow cytometry according to the intensity of rhodamine 123 uptake in cells.
Results:
Both diamide and cyclosporin A significantly enhanced As(2)O(3)-induced apoptosis in NB4 cells. The DeltaPsim collapse induced by As(2)O(3) was also enforced by combined treatment with diamide or cyclospo-rin A. 1 micromol/L As(2)O(3) alone treatment for 72 hours led to DeltaPsim disruption in 27.9% of cells, while combined treatment of As(2)O(3) and diamide or cyclosporin A increased DeltaPsim disruption cells to 59.7% and 42.2%, respectively.
Conclusions:
As(2)O(3)-induced DeltaPsim disruption possibly involves with thiol oxidation or crosslink of important components especially ANT-related molecules.
