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Biochem Biophys Res Commun. 2004 Jul 30;320(3):932-8.

Inhibition of phosphatidylinositol 3'-kinase induces preferentially killing of PTEN-null T leukemias through AKT pathway.

Author information

1
King Fahad National Center for Children's Cancer and Research, MBC# 98-16, P.O. Box 3354, Riyadh 11211, Saudi Arabia. shahab@kfshrc.edu.sa

Abstract

We examined the functional role of the phosphatidylinositol 3'-kinase pathway in the growth and survival of cell lines of T-cell origin. Pharmacological inhibition of PI3'-kinase using LY294002 resulted in apoptosis of acute lymphoblastic T-cell leukemia (T-ALL) cell lines including CEM, Jurkat, and MOLT-4. On the other hand, the cutaneous T-cell lymphoma cell line HUT-78 was found to be refractory to LY294002- inducible apoptosis. Sensitivity or resistance to pharmacological inhibitors of PI3'-kinase correlated with tumor suppressor PTEN gene expression, as sensitive T-ALL cells do not express PTEN and have high level of activated AKT, in contrast to HUT-78 cells. Our data demonstrate that inhibition of PI3'-kinase results in dephosphorylation of AKT and partial inhibition of Bcl-xL expression in T-ALL cells, but not in HUT-78 cells. Interestingly, HUT-78 cells were also found to express higher levels of Bcl-xL protein as compared to T-ALL cells. Inhibition of PI3'-kinase also induces release of cytochrome c from mitochondria and activation of caspase-3 and PARP in all T-ALL cell lines tested, but not in HUT-78 cells. Taken altogether, our data demonstrate that the PI3'-kinase/AKT pathway plays a major role in the growth and survival of PTEN-null T-ALL cells, and identify this cascade as promising target for therapeutic intervention in acute T-cell leukemias.

PMID:
15240138
DOI:
10.1016/j.bbrc.2004.06.038
[Indexed for MEDLINE]

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