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Use of radiolabelled choline as a pharmacodynamic marker for the signal transduction inhibitor geldanamycin

Title: Use of radiolabelled choline as a pharmacodynamic marker for the signal transduction inhibitor geldanamycin
Authors: Liu, D
Hutchinson, OC
Osman, S
Price, P
Workman, P
Aboagye, EO
Item Type: Journal Article
Abstract: There is an urgent need to develop non-invasive pharmacodynamic endpoints for the evaluation of new molecular therapeutics that inhibit signal transduction. We hypothesised that, when labelled appropriately, changes in choline kinetics could be used to assess geldanamycin pharmacodynamics, which involves inhibition of the HSP90 molecular chaperone→Raf1→Mitogenic Extracellular Kinase→Extracellular Signal-Regulated Kinase 1 and 2 signal transduction pathway. Towards identifying a potential pharmacodynamic marker response, we have studied radiolabelled choline metabolism in HT29 human colon carcinoma cells following treatment with geldanamycin. We studied the effects of geldanamycin, on net cellular accumulation of (methyl-14C)choline and (methyl-14C)phosphocholine production. In parallel experiments, the effects of geldanamycin on extracellular signal-regulated kinase 1 and 2 phosphorylation and cell viability were also assessed. Additional validation studies were carried out with the mitogenic extracellular kinase inhibitor U0126 as a positive control; a cyclin-dependent kinase-2 inhibitor roscovitine and the phosphatidylinositol 3-kinase inhibitor LY294002 as negative controls. Hemicholinium-3, an inhibitor of choline transport and choline kinase activity was included as an additional control. In exponentially growing HT29 cells, geldanamycin inhibited extracellular signal-regulated kinase 1 and 2 phosphorylation in a concentration- and time-dependent manner. These changes were associated with a reduction in (methyl-14C)choline uptake, (methyl-14C) phosphocholine production and cell viability. Brief exposure to U0126, suppressed phosphocholine production to the same extent as Hemicholinium-3. In contrast to geldanamycin and U0126, which act upstream of extracellular signal-regulated kinase 1 and 2, roscovitine and LY294002 failed to suppress phosphocholine production. Our results suggest that when labelled with carbon-11 isotope, (methyl-11C)choline may be a useful pharmacodynamic marker for the non-invasive evaluation of geldanamycin analogues.
Issue Date: 23-Sep-2002
Date of Acceptance: 22-Jul-2002
URI: http://hdl.handle.net/10044/1/70333
DOI: https://dx.doi.org/10.1038/sj.bjc.6600558
ISSN: 0007-0920
Publisher: Springer Nature [academic journals on nature.com]
Start Page: 783
End Page: 789
Journal / Book Title: British Journal of Cancer
Volume: 87
Copyright Statement: © 2002 Cancer Research UK. All rights reserved. From twelve months after its original publication, this work is licensed under the Creative Commons Attribution-NonCommercial-Share Alike 3.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/3.0/
Keywords: Science & Technology
Life Sciences & Biomedicine
Oncology
choline
ERK1/2
geldanamycin
phosphocholine
pharmacodynamic
HSP90 MOLECULAR CHAPERONE
CYCLIN-DEPENDENT KINASES
PHOSPHATIDYLINOSITOL 3-KINASE
GROWTH-FACTORS
CELL-LINES
PROTEIN
RAF-1
TUMOR
17-ALLYLAMINO-17-DEMETHOXYGELDANAMYCIN
DESTABILIZATION
Benzoquinones
Blotting, Western
Carbon Radioisotopes
Cell Division
Cell Survival
Choline
Humans
Lactams, Macrocyclic
MAP Kinase Signaling System
Mitogen-Activated Protein Kinases
Phosphorylation
Phosphorylcholine
Quinones
Tumor Cells, Cultured
Tumor Cells, Cultured
Humans
Carbon Radioisotopes
Choline
Lactams, Macrocyclic
Phosphorylcholine
Quinones
Benzoquinones
Mitogen-Activated Protein Kinases
Blotting, Western
Cell Division
Cell Survival
MAP Kinase Signaling System
Phosphorylation
Science & Technology
Life Sciences & Biomedicine
Oncology
choline
ERK1/2
geldanamycin
phosphocholine
pharmacodynamic
HSP90 MOLECULAR CHAPERONE
CYCLIN-DEPENDENT KINASES
PHOSPHATIDYLINOSITOL 3-KINASE
GROWTH-FACTORS
CELL-LINES
PROTEIN
RAF-1
TUMOR
17-ALLYLAMINO-17-DEMETHOXYGELDANAMYCIN
DESTABILIZATION
Oncology & Carcinogenesis
1112 Oncology and Carcinogenesis
Publication Status: Published
Appears in Collections:Department of Surgery and Cancer