| The phosphoinositide 3-kinase inhibitor PI-103 downregulates choline kinase alpha leading to phosphocholine and total choline decrease detected by magnetic resonance spectroscopy. | |
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MedLine Citation:
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PMID: 20551061 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The phosphoinositide 3-kinase (PI3K) pathway is a major target for cancer drug development. PI-103 is an isoform-selective class I PI3K and mammalian target of rapamycin inhibitor. The aims of this work were as follows: first, to use magnetic resonance spectroscopy (MRS) to identify and develop a robust pharmacodynamic (PD) biomarker for target inhibition and potentially tumor response following PI3K inhibition; second, to evaluate mechanisms underlying the MRS-detected changes. Treatment of human PTEN null PC3 prostate and PIK3CA mutant HCT116 colon carcinoma cells with PI-103 resulted in a concentration- and time-dependent decrease in phosphocholine (PC) and total choline (tCho) levels (P < 0.05) detected by phosphorus ((31)P)- and proton ((1)H)-MRS. In contrast, the cytotoxic microtubule inhibitor docetaxel increased glycerophosphocholine and tCho levels in PC3 cells. PI-103-induced MRS changes were associated with alterations in the protein expression levels of regulatory enzymes involved in lipid metabolism, including choline kinase alpha (ChoK(alpha)), fatty acid synthase (FAS), and phosphorylated ATP-citrate lyase (pACL). However, a strong correlation (r(2) = 0.9, P = 0.009) was found only between PC concentrations and ChoK(alpha) expression but not with FAS or pACL. This study identified inhibition of ChoK(alpha) as a major cause of the observed change in PC levels following PI-103 treatment. We also showed the capacity of (1)H-MRS, a clinically well-established technique with higher sensitivity and wider applicability compared with (31)P-MRS, to assess response to PI-103. Our results show that monitoring the effects of PI3K inhibitors by MRS may provide a noninvasive PD biomarker for PI3K inhibition and potentially of tumor response during early-stage clinical trials with PI3K inhibitors. |
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Authors:
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Nada M S Al-Saffar; L Elizabeth Jackson; Florence I Raynaud; Paul A Clarke; Ana Ramírez de Molina; Juan C Lacal; Paul Workman; Martin O Leach |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2010-06-15 |
Journal Detail:
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Title: Cancer research Volume: 70 ISSN: 1538-7445 ISO Abbreviation: Cancer Res. Publication Date: 2010 Jul |
Date Detail:
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Created Date: 2010-07-02 Completed Date: 2010-08-09 Revised Date: 2011-07-19 |
Medline Journal Info:
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Nlm Unique ID: 2984705R Medline TA: Cancer Res Country: United States |
Other Details:
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Languages: eng Pagination: 5507-17 Citation Subset: IM |
Copyright Information:
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Copyright 2010 AACR. |
Affiliation:
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Cancer Research UK and EPSRC Cancer Imaging Centre, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, Sutton, Surrey, United Kingdom. Nada.Al-Saffar@icr.ac.uk |
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| MeSH Terms | |
Descriptor/Qualifier:
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Adenocarcinoma
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genetics,
metabolism Cell Line, Tumor Choline / metabolism* Choline Kinase / biosynthesis, genetics, metabolism* Down-Regulation / drug effects Furans / pharmacology* HCT116 Cells Humans Magnetic Resonance Spectroscopy Male Membrane Proteins / deficiency PTEN Phosphohydrolase / deficiency Phosphatidylinositol 3-Kinases / antagonists & inhibitors*, metabolism Phosphorylcholine / metabolism* Prostatic Neoplasms / genetics, metabolism Pyridines / pharmacology* Pyrimidines / pharmacology* |
| Grant Support | |
ID/Acronym/Agency:
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A10334//Cancer Research UK; A8274//Cancer Research UK; C1060/6916//Department of Health; C1060/A10334//Department of Health; C309/A2187//Cancer Research UK; C309/A8274//Cancer Research UK; //Medical Research Council |
| Chemical | |
Reg. No./Substance:
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0/Furans; 0/Membrane Proteins; 0/PI103; 0/Pyridines; 0/Pyrimidines; 107-73-3/Phosphorylcholine; 62-49-7/Choline; EC 2.7.1.-/Phosphatidylinositol 3-Kinases; EC 2.7.1.32/CHKA protein, human; EC 2.7.1.32/Choline Kinase; EC 3.1.3.48/TPTE protein, human; EC 3.1.3.67/PTEN Phosphohydrolase |
| Comments/Corrections | |
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