| Popis: |
2 Akt (PKB), a pivotal protein kinase which can block apoptosis and promotes cell survival, was identified to be chiefly down-regulated in a dose-dependent manner following CEES treatment. Functional analysis showed that the attendant Akt activity was simultaneously reduced. 3 PDK1, an upstream eAector of Akt, was also down-regulated following CEES exposure, but two other upstream eAectors of Akt, PI3-K and PDK2, remained unchanged. 4 The phosphorylation of Akt at Ser 473 and Thr 308 was significantly decreased following CEES treatment, reflecting the suppressed kinase activity of both PDK1 and PDK2. 5 Concurrently, the anti-apoptotic genes, Bcl family, were down-regulated, in sharp contrast to the striking up-regulation of some death executioner genes, caspase 3, 6, and 8. 6 Based on these findings, a model of CEES-induced apoptosis was established. These results suggest that CEES attacked the Akt pathway, directly or indirectly, by inhibiting Akt transcription, translation, and post-translation modification. 7 Taken together, upon exposure to CEES, apoptosis was induced in Jurkat cells via the downregulation of the survival factors that normally prevent the activation of the death executioner genes, the caspases. British Journal of Pharmacology (2002) 137, 245‐252. doi:10.1038/sj.bjp.0704856 |
