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

Authors
  • Uddin, Shahab
  • Hussain, Azhar
  • Al-Hussein, Khaled
  • Platanias, Leonidas C
  • Bhatia, Kishor G
Type
Published Article
Journal
Biochemical and biophysical research communications
Publication Date
Jul 30, 2004
Volume
320
Issue
3
Pages
932–938
Identifiers
PMID: 15240138
Source
Medline
License
Unknown

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.

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