Differential involvement of reactive oxygen species in apoptosis caused by the inhibition of protein phosphatase 2A in Jurkat and CCRF-CEM human T-leukemia cells.
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| Abstract |
A better understanding of dysregulated signaling pathways in cancer cells may suggest novel strategies to prevent tumor development and/or progression. Here we show that Jurkat and CCRF-CEM human T-leukemia cell lines were more sensitive than normal human T cells to the cytotoxic effect of inhibiting protein phosphatase 2A (PP2A). Inhibition of PP2A by okadaic acid (OA) caused T-leukemia cells to die by apoptosis, as indicated by DNA fragmentation, caspase-3 activation, loss of mitochondrial membrane potential (DeltaPsi(m)), and changes in nuclear morphology that were consistent with apoptosis. PP2A might therefore be a useful intracellular target for the treatment of T cell-derived leukemias. We also observed that reactive oxygen species (ROS) were generated in response to PP2A inhibition in T-leukemia cells. However, loss of DeltaPsi(m) that resulted from PP2A inhibition was not prevented by exogenous antioxidants (glutathione and N-acetyl-cysteine), indicating that OA-induced changes in mitochondrial membrane permeability were not a consequence of ROS production. Moreover, exogenous antioxidants protected CCRF-CEM T-leukemia cells from apoptosis caused by PP2A inhibition but failed to prevent OA-induced apoptosis in Jurkat T-leukemia cells, indicating a differential role for ROS in apoptosis caused by PP2A inhibition in two different human T-leukemia cell lines.
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| Authors | Robert T M Boudreau, David M Conrad, David W Hoskin |
| Journal | Experimental and molecular pathology (Exp Mol Pathol) Vol. 83 Issue 3 Pg. 347-56 (Dec 2007) ISSN: 0014-4800 [Print] Netherlands |
| PMID | 17936751 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't) |
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