Abstract
It has become apparent that regulation of protein translation is an important determinant in controlling cell growth and leukemic transformation. The phosphoinositide 3-kinase (PI3K)/phosphatase and tensin homologue deleted on chromosome ten (PTEN)/Akt/mammalian target of rapamycin (mTOR) pathway is often implicated in sensitivity and resistance to therapy. Dysregulated signaling through the PI3K/PTEN/Akt/mTOR pathway is often the result of genetic alterations in critical components in this pathway as well as mutations at upstream growth factor receptors. Furthermore, this pathway is activated by autocrine transformation mechanisms. PTEN is a critical tumor suppressor gene and its dysregulation results in the activation of Akt. PTEN is often mutated, silenced and is often haploinsufficient. The mTOR complex1 (mTORC1) regulates the assembly of the eukaryotic initiation factor4F complex, which is critical for the translation of mRNAs that are important for cell growth, prevention of apoptosis and transformation. These mRNAs have long 5'-untranslated regions that are G+C rich, rendering them difficult to translate. Elevated mTORC1 activity promotes the translation of these mRNAs via the phosphorylation of 4E-BP1. mTORC1 is a target of rapamycin and novel active-site inhibitors that directly target the TOR kinase activity. Although rapamycin and novel rapalogs are usually cytostatic and not cytotoxic for leukemic cells, novel inhibitors that target the kinase activities of PI3K and mTOR may prove more effective for leukemia therapy.
Publication types
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Research Support, Non-U.S. Gov't
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Review
MeSH terms
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Antineoplastic Agents / pharmacology*
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Antineoplastic Agents / therapeutic use
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Apoptosis / drug effects
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Apoptosis / genetics
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Drug Design
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Drug Resistance, Neoplasm / drug effects
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Drug Resistance, Neoplasm / genetics
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Gene Expression Regulation, Leukemic / drug effects*
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Gene Expression Regulation, Leukemic / genetics
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Humans
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Leukemia / drug therapy*
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Leukemia / genetics
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Mechanistic Target of Rapamycin Complex 1
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MicroRNAs / genetics
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Molecular Targeted Therapy*
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Multiprotein Complexes / antagonists & inhibitors
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Multiprotein Complexes / drug effects
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Multiprotein Complexes / physiology
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Neoplasm Proteins / antagonists & inhibitors
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Neoplasm Proteins / genetics
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Neoplasm Proteins / physiology*
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Neoplastic Stem Cells / drug effects
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PTEN Phosphohydrolase / antagonists & inhibitors
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PTEN Phosphohydrolase / genetics
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PTEN Phosphohydrolase / physiology*
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Phosphatidylinositol 3-Kinases / genetics
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Phosphatidylinositol 3-Kinases / physiology*
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Phosphoinositide-3 Kinase Inhibitors
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Phosphorylation / drug effects
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Protein Biosynthesis / drug effects*
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Protein Processing, Post-Translational / drug effects
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Proteins / antagonists & inhibitors
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Proteins / drug effects
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Proteins / physiology
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Proto-Oncogene Proteins c-akt / antagonists & inhibitors
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Proto-Oncogene Proteins c-akt / genetics
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Proto-Oncogene Proteins c-akt / physiology*
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Pseudogenes
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RNA, Messenger / genetics
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RNA, Neoplasm / genetics
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Signal Transduction / drug effects*
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TOR Serine-Threonine Kinases / antagonists & inhibitors
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TOR Serine-Threonine Kinases / genetics
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TOR Serine-Threonine Kinases / physiology*
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Transcription Factors / antagonists & inhibitors
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Transcription Factors / drug effects
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Transcription Factors / physiology
Substances
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Antineoplastic Agents
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CRTC2 protein, human
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MicroRNAs
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Multiprotein Complexes
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Neoplasm Proteins
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Phosphoinositide-3 Kinase Inhibitors
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Proteins
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RNA, Messenger
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RNA, Neoplasm
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Transcription Factors
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MTOR protein, human
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AKT1 protein, human
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Mechanistic Target of Rapamycin Complex 1
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Proto-Oncogene Proteins c-akt
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TOR Serine-Threonine Kinases
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PTEN Phosphohydrolase
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PTEN protein, human