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Witney TH, Alam IS, Turton DR, Smith G, Carroll L, Brickute D, Twyman FJ, Nguyen QD, Tomasi G, Awais RO, Aboagye EO. Evaluation of deuterated 18F- and 11C-labeled choline analogs for cancer detection by positron emission tomography. Clin Cancer Res 2012; 18:1063-72. [PMID: 22235095 DOI: 10.1158/1078-0432.ccr-11-2462] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
PURPOSE (11)C-Choline-positron emission tomography (PET) has been exploited to detect the aberrant choline metabolism in tumors. Radiolabeled choline uptake within the imaging time is primarily a function of transport, phosphorylation, and oxidation. Rapid choline oxidation, however, complicates interpretation of PET data. In this study, we investigated the biologic basis of the oxidation of deuterated choline analogs and assessed their specificity in human tumor xenografts. EXPERIMENTAL DESIGN (11)C-Choline, (11)C-methyl-[1,2-(2)H(4)]-choline ((11)C-D4-choline), and (18)F-D4-choline were synthesized to permit comparison. Biodistribution, metabolism, small-animal PET studies, and kinetic analysis of tracer uptake were carried out in human colon HCT116 xenograft-bearing mice. RESULTS Oxidation of choline analogs to betaine was highest with (11)C-choline, with reduced oxidation observed with (11)C-D4-choline and substantially reduced with (18)F-D4-choline, suggesting that both fluorination and deuteration were important for tracer metabolism. Although all tracers were converted intracellularly to labeled phosphocholine (specific signal), the higher rate constants for intracellular retention (K(i) and k(3)) of (11)C-choline and (11)C-D4-choline, compared with (18)F-D4-choline, were explained by the rapid conversion of the nonfluorinated tracers to betaine within HCT116 tumors. Imaging studies showed that the uptake of (18)F-D4-choline in three tumors with similar radiotracer delivery (K(1)) and choline kinase α expression-HCT116, A375, and PC3-M-were the same, suggesting that (18)F-D4-choline has utility for cancer detection irrespective of histologic type. CONCLUSION We have shown here that both deuteration and fluorination combine to provide protection against choline oxidation in vivo. (18)F-D4-choline showed the highest selectivity for phosphorylation and warrants clinical evaluation.
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Affiliation(s)
- Timothy H Witney
- Comprehensive Cancer Imaging Centre at Imperial College, Faculty of Medicine, Imperial College London, United Kingdom
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Abstract
Abnormal choline metabolism is emerging as a metabolic hallmark that is associated with oncogenesis and tumour progression. Following transformation, the modulation of enzymes that control anabolic and catabolic pathways causes increased levels of choline-containing precursors and breakdown products of membrane phospholipids. These increased levels are associated with proliferation, and recent studies emphasize the complex reciprocal interactions between oncogenic signalling and choline metabolism. Because choline-containing compounds are detected by non-invasive magnetic resonance spectroscopy (MRS), increased levels of these compounds provide a non-invasive biomarker of transformation, staging and response to therapy. Furthermore, enzymes of choline metabolism, such as choline kinase, present novel targets for image-guided cancer therapy.
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Affiliation(s)
- Kristine Glunde
- The Johns Hopkins University In Vivo Cellular and Molecular Imaging Center, The Russell H. Morgan Department of Radiology and Radiological Science, 720 Rutland Avenue, 212 Traylor Building, Baltimore, Maryland 21205, USA
- Sidney Kimmel Comprehensive Cancer Center, Baltimore, Maryland 21231, USA
| | - Zaver M. Bhujwalla
- The Johns Hopkins University In Vivo Cellular and Molecular Imaging Center, The Russell H. Morgan Department of Radiology and Radiological Science, 720 Rutland Avenue, 212 Traylor Building, Baltimore, Maryland 21205, USA
- Sidney Kimmel Comprehensive Cancer Center, Baltimore, Maryland 21231, USA
| | - Sabrina M. Ronen
- Department of Radiology, University of California San Francisco School of Medicine, UCSF Mission Bay Campus, Byers Hall, San Francisco, California CA94158-2330, USA
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Darpolor MM, Kennealey PT, Carl Le H, Zakian KL, Ackerstaff E, Rizwan A, Chen JH, Sambol EB, Schwartz GK, Singer S, Koutcher JA. Preclinical study of treatment response in HCT-116 cells and xenografts with (1) H-decoupled (31) P MRS. NMR IN BIOMEDICINE 2011; 24:1159-1168. [PMID: 21994185 PMCID: PMC3201722 DOI: 10.1002/nbm.1674] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2010] [Revised: 12/15/2010] [Accepted: 12/16/2010] [Indexed: 05/31/2023]
Abstract
The topoisomerase I inhibitor, irinotecan, and its active metabolite SN-38 have been shown to induce G(2) /M cell cycle arrest without significant cell death in human colon carcinoma cells (HCT-116). Subsequent treatment of these G(2) /M-arrested cells with the cyclin-dependent kinase inhibitor, flavopiridol, induced these cells to undergo apoptosis. The goal of this study was to develop a noninvasive metabolic biomarker for early tumor response and target inhibition of irinotecan followed by flavopiridol treatment in a longitudinal study. A total of eleven mice bearing HCT-116 xenografts were separated into two cohorts where one cohort was administered saline and the other treated with a sequential course of irinotecan followed by flavopiridol. Each mouse xenograft was longitudinally monitored with proton ((1) H)-decoupled phosphorus ((31) P) magnetic resonance spectroscopy (MRS) before and after treatment. A statistically significant decrease in phosphocholine (p = 0.0004) and inorganic phosphate (p = 0.0103) levels were observed in HCT-116 xenografts following treatment, which were evidenced within twenty-four hours of treatment completion. Also, a significant growth delay was found in treated xenografts. To discern the underlying mechanism for the treatment response of the xenografts, in vitro HCT-116 cell cultures were investigated with enzymatic assays, cell cycle analysis, and apoptotic assays. Flavopiridol had a direct effect on choline kinase as measured by a 67% reduction in the phosphorylation of choline to phosphocholine. Cells treated with SN-38 alone underwent 83 ± 5% G(2) /M cell cycle arrest compared to untreated cells. In cells, flavopiridol alone induced 5 ± 1% apoptosis while the sequential treatment (SN-38 then flavopiridol) resulted in 39 ± 10% apoptosis. In vivo (1) H-decoupled (31) P MRS indirectly measures choline kinase activity. The decrease in phosphocholine may be a potential indicator of early tumor response to the sequential treatment of irinotecan followed by flavopiridol in noninvasive and/or longitudinal studies.
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Affiliation(s)
- Moses M. Darpolor
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Peter T. Kennealey
- Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - H Carl Le
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Kristen L. Zakian
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Ellen Ackerstaff
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Asif Rizwan
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Jin-Hong Chen
- Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Elliot B. Sambol
- Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Gary K. Schwartz
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Samuel Singer
- Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Jason A. Koutcher
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
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Martín-Cantalejo Y, Sáez B, Monterde M, Murillo M, Braña M. Synthesis and biological activity of new bispyridinium salts of 4,4′-bispyridyl-5,5′-perfluoroalkyl-2,2′-bisoxazoles. Eur J Med Chem 2011; 46:5662-7. [DOI: 10.1016/j.ejmech.2011.09.046] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Revised: 09/23/2011] [Accepted: 09/26/2011] [Indexed: 12/26/2022]
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A novel small molecule antagonist of choline kinase-α that simultaneously suppresses MAPK and PI3K/AKT signaling. Oncogene 2011; 30:3370-80. [PMID: 21423211 PMCID: PMC3136659 DOI: 10.1038/onc.2011.51] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Choline kinase-α expression and activity are increased in multiple human neoplasms as a result of growth factor stimulation and activation of cancer-related signaling pathways. The product of choline kinase-α, phosphocholine, serves as an essential metabolic reservoir for the production of phosphatidylcholine, the major phospholipid constituent of membranes and substrate for the production of lipid second messengers. Using in silico screening for small molecules that may interact with the choline kinase-α substrate binding domain, we identified a novel competitive inhibitor, N-(3,5-dimethylphenyl)-2-[[5-(4-ethylphenyl)-1H-1,2,4-triazol-3-yl]sulfanyl] acetamide (termed CK37) that inhibited purified recombinant human choline kinase-α activity, reduced the steady-state concentration of phosphocholine in transformed cells, and selectively suppressed the growth of neoplastic cells relative to normal epithelial cells. Choline kinase-α activity is required for the downstream production of phosphatidic acid, a promoter of several Ras signaling pathways. CK37 suppressed MAPK and PI3K/AKT signaling, disrupted actin cytoskeletal organization, and reduced plasma membrane ruffling. Finally, administration of CK37 significantly decreased tumor growth in a lung tumor xenograft mouse model, suppressed tumor phosphocholine, and diminished activating phosphorylations of ERK and AKT in vivo. Together, these results further validate choline kinase-α as a molecular target for the development of agents that interrupt Ras signaling pathways, and indicate that receptor-based computational screening should facilitate the identification of new classes of choline kinase-α inhibitors.
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56
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Jeong SW, Seo YR. Transcriptomic analysis of Caenorhabditis elegans exposed to nickel (II) acetate using microarray. BIOCHIP JOURNAL 2011. [DOI: 10.1007/s13206-011-5112-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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57
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Gallego-Ortega D, Gómez del Pulgar T, Valdés-Mora F, Cebrián A, Lacal JC. Involvement of human choline kinase alpha and beta in carcinogenesis: a different role in lipid metabolism and biological functions. ACTA ACUST UNITED AC 2010; 51:183-94. [PMID: 21035492 DOI: 10.1016/j.advenzreg.2010.09.010] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Accepted: 09/05/2010] [Indexed: 10/18/2022]
Abstract
We have summarized here the importance of ChoKα1 in human carcinogenesis. ChoKα1 displays its oncogenic activity through activation of specific signaling pathways that influence on cell proliferation and survival. It is overexpressed in a large number of human tumors with an incidence of 40-60% of all tumors investigated. Currently, there is an active effort in the development of strategies to knockdown the activity of ChoKα through specific siRNA or small molecules inhibitors. Results from genetic silencing or from treatment with MN58b, a well characterized ChoKα inhibitor showing antiproliferative and antitumoral effect in mice xenografts, provide strong support to this concept, indicating that the design of new antitumoral drugs must be selective against this isoform. However, affecting the other two known isoforms of ChoK may have also therapeutic consequences since the physiologically active form of ChoK may be constituted by homo or heterodimers. Furthermore, alteration of the ChoKβ activity might lead to a change in the lipid content of the cells of particular tissues such as skeletal muscle as described in the ChoKβ null mice (Sher et al., 2006). Finally, the identification of the ChoKα1 isoform as an excellent novel tool for the diagnosis and prognosis of cancer patients may have clinical consequences of immediate usefulness. On one hand, the use of specific monoclonal antibodies against ChoKα1 as a tool for diagnosis in paraffin embedded samples from patient biopsies, through standard immunohistochemistry techniques, can now be achieved (Gallego-Ortega et al., 2006). On the other hand, it has been recently described the prognostic value of determination of ChoKα1 expression levels in non-small cell lung cancer using real time quantitative PCR technology (Ramírez de Molina et al., 2007). Therefore, further research should be supported on the utility of ChoK isoforms as a promising area to improve cancer diagnosis and treatment.
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58
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Kenny LM, Contractor KB, Hinz R, Stebbing J, Palmieri C, Jiang J, Shousha S, Al-Nahhas A, Coombes RC, Aboagye EO. Reproducibility of [11C]Choline-Positron Emission Tomography and Effect of Trastuzumab. Clin Cancer Res 2010; 16:4236-45. [DOI: 10.1158/1078-0432.ccr-10-0468] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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59
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Wu G, Vance DE. Choline kinase and its functionThis paper is one of a selection of papers published in this special issue entitled “Second International Symposium on Recent Advances in Basic, Clinical, and Social Medicine” and has undergone the Journal's usual peer review process. Biochem Cell Biol 2010; 88:559-64. [DOI: 10.1139/o09-160] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Choline kinase (CK) was discovered in 1953. Progress in understanding the function of CK was slow until its purification in 1984. The subsequent cloning and expression of the cDNA led to the description of the gene structures. Two genes encode choline kinase, Chka and Chkb, and 3 isoforms of the enzyme have been identified — CKα-1, CKα-2, and CKβ — and the active form of CK is a hetero- or homo-dimer. More recently, gene-disrupted mice have been described. Mice that lack CKα die early in embryogenesis. In contrast, mice that lack CKβ survive to adulthood, but develop hindlimb muscular dystrophy and forelimb bone deformity. It has been shown that this hindlimb muscular dystrophy is due to decreased biosynthesis of phosphatidylcholine and increased catabolism of phosphatidylcholine in the hindlimbs, but not the forelimbs, of mice. CK and its product phosphocholine have also been implicated in development of numerous cancers. Thus, a possible treatment for some kinds of cancer may involve drug inhibition of CK or targeting the expression of CK with RNA interference. In the mid 1950s it was clear that CK was important for the biosynthesis of phosphatidylcholine, but no one predicted a role for CK in muscular dystrophy, bone deformities, or cancer.
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Affiliation(s)
- Gengshu Wu
- The Group on the Molecular and Cell Biology of Lipids and the Department of Biochemistry, University of Alberta, Edmonton, AB T6G2S2 Canada
| | - Dennis E. Vance
- The Group on the Molecular and Cell Biology of Lipids and the Department of Biochemistry, University of Alberta, Edmonton, AB T6G2S2 Canada
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60
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Hong BS, Allali-Hassani A, Tempel W, Finerty PJ, MacKenzie F, Dimov S, Vedadi M, Park HW. Crystal structures of human choline kinase isoforms in complex with hemicholinium-3: single amino acid near the active site influences inhibitor sensitivity. J Biol Chem 2010; 285:16330-40. [PMID: 20299452 PMCID: PMC2871500 DOI: 10.1074/jbc.m109.039024] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Revised: 02/28/2010] [Indexed: 12/03/2022] Open
Abstract
Human choline kinase (ChoK) catalyzes the first reaction in phosphatidylcholine biosynthesis and exists as ChoKalpha (alpha1 and alpha2) and ChoKbeta isoforms. Recent studies suggest that ChoK is implicated in tumorigenesis and emerging as an attractive target for anticancer chemotherapy. To extend our understanding of the molecular mechanism of ChoK inhibition, we have determined the high resolution x-ray structures of the ChoKalpha1 and ChoKbeta isoforms in complex with hemicholinium-3 (HC-3), a known inhibitor of ChoK. In both structures, HC-3 bound at the conserved hydrophobic groove on the C-terminal lobe. One of the HC-3 oxazinium rings complexed with ChoKalpha1 occupied the choline-binding pocket, providing a structural explanation for its inhibitory action. Interestingly, the HC-3 molecule co-crystallized with ChoKbeta was phosphorylated in the choline binding site. This phosphorylation, albeit occurring at a very slow rate, was confirmed experimentally by mass spectroscopy and radioactive assays. Detailed kinetic studies revealed that HC-3 is a much more potent inhibitor for ChoKalpha isoforms (alpha1 and alpha2) compared with ChoKbeta. Mutational studies based on the structures of both inhibitor-bound ChoK complexes demonstrated that Leu-401 of ChoKalpha2 (equivalent to Leu-419 of ChoKalpha1), or the corresponding residue Phe-352 of ChoKbeta, which is one of the hydrophobic residues neighboring the active site, influences the plasticity of the HC-3-binding groove, thereby playing a key role in HC-3 sensitivity and phosphorylation.
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Affiliation(s)
| | | | | | | | | | | | | | - Hee-Won Park
- From the Structural Genomics Consortium and
- Department of Pharmacology, University of Toronto, Toronto, Ontario M5G 1L7, Canada
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61
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Gallego-Ortega D, Ramirez de Molina A, Ramos MA, Valdes-Mora F, Barderas MG, Sarmentero-Estrada J, Lacal JC. Differential role of human choline kinase alpha and beta enzymes in lipid metabolism: implications in cancer onset and treatment. PLoS One 2009; 4:e7819. [PMID: 19915674 PMCID: PMC2773002 DOI: 10.1371/journal.pone.0007819] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Accepted: 10/07/2009] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The Kennedy pathway generates phosphocoline and phosphoethanolamine through its two branches. Choline Kinase (ChoK) is the first enzyme of the Kennedy branch of synthesis of phosphocholine, the major component of the plasma membrane. ChoK family of proteins is composed by ChoKalpha and ChoKbeta isoforms, the first one with two different variants of splicing. Recently ChoKalpha has been implicated in the carcinogenic process, since it is over-expressed in a variety of human cancers. However, no evidence for a role of ChoKbeta in carcinogenesis has been reported. METHODOLOGY/PRINCIPAL FINDINGS Here we compare the in vitro and in vivo properties of ChoKalpha1 and ChoKbeta in lipid metabolism, and their potential role in carcinogenesis. Both ChoKalpha1 and ChoKbeta showed choline and ethanolamine kinase activities when assayed in cell extracts, though with different affinity for their substrates. However, they behave differentially when overexpressed in whole cells. Whereas ChoKbeta display an ethanolamine kinase role, ChoKalpha1 present a dual choline/ethanolamine kinase role, suggesting the involvement of each ChoK isoform in distinct biochemical pathways under in vivo conditions. In addition, while overexpression of ChoKalpha1 is oncogenic when overexpressed in HEK293T or MDCK cells, ChoKbeta overexpression is not sufficient to induce in vitro cell transformation nor in vivo tumor growth. Furthermore, a significant upregulation of ChoKalpha1 mRNA levels in a panel of breast and lung cancer cell lines was found, but no changes in ChoKbeta mRNA levels were observed. Finally, MN58b, a previously described potent inhibitor of ChoK with in vivo antitumoral activity, shows more than 20-fold higher efficiency towards ChoKalpha1 than ChoKbeta. CONCLUSION/SIGNIFICANCE This study represents the first evidence of the distinct metabolic role of ChoKalpha and ChoKbeta isoforms, suggesting different physiological roles and implications in human carcinogenesis. These findings constitute a step forward in the design of an antitumoral strategy based on ChoK inhibition.
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Affiliation(s)
- David Gallego-Ortega
- Translational Oncology Unit, CSIC-UAM-La Paz, Instituto de Investigaciones Biomédicas, Madrid, Spain
| | - Ana Ramirez de Molina
- Translational Oncology Unit, CSIC-UAM-La Paz, Instituto de Investigaciones Biomédicas, Madrid, Spain
- TCD Pharma, Centro Nacional de Biotecnología, Madrid, Spain
| | - Maria Angeles Ramos
- Translational Oncology Unit, CSIC-UAM-La Paz, Instituto de Investigaciones Biomédicas, Madrid, Spain
- TCD Pharma, Centro Nacional de Biotecnología, Madrid, Spain
| | - Fatima Valdes-Mora
- Translational Oncology Unit, CSIC-UAM-La Paz, Instituto de Investigaciones Biomédicas, Madrid, Spain
| | - Maria Gonzalez Barderas
- Department of Vascular Physiopathology, Hospital Nacional de Paraplejicos, SESCAM, Toledo, Spain
| | - Jacinto Sarmentero-Estrada
- Translational Oncology Unit, CSIC-UAM-La Paz, Instituto de Investigaciones Biomédicas, Madrid, Spain
- TCD Pharma, Centro Nacional de Biotecnología, Madrid, Spain
| | - Juan Carlos Lacal
- Translational Oncology Unit, CSIC-UAM-La Paz, Instituto de Investigaciones Biomédicas, Madrid, Spain
- TCD Pharma, Centro Nacional de Biotecnología, Madrid, Spain
- * E-mail:
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Selective inhibition of choline kinase simultaneously attenuates MAPK and PI3K/AKT signaling. Oncogene 2009; 29:139-49. [PMID: 19855431 DOI: 10.1038/onc.2009.317] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Choline is an essential anabolic substrate for the synthesis of phospholipids. Choline kinase phosphorylates choline to phosphocholine that serves as a precursor for the production of phosphatidylcholine, the major phospholipid constituent of membranes and substrate for the synthesis of lipid signaling molecules. Nuclear magnetic resonance (NMR)-based metabolomic studies of human tumors have identified a marked increase in the intracellular concentration of phosphocholine relative to normal tissues. We postulated that the observed intracellular pooling of phosphocholine may be required to sustain the production of the pleiotropic lipid second messenger, phosphatidic acid. Phosphatidic acid is generated from the cleavage of phosphatidylcholine by phospholipase D2 and is a key activator of the mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K)/AKT survival signaling pathways. In this study we show that the steady-state concentration of phosphocholine is increased by the ectopic expression of oncogenic H-Ras(V12) in immortalized human bronchial epithelial cells. We then find that small interfering RNA (siRNA) silencing of choline kinase expression in transformed HeLa cells completely abrogates the high concentration of phosphocholine, which in turn decreases phosphatidylcholine, phosphatidic acid and signaling through the MAPK and PI3K/AKT pathways. This simultaneous reduction in survival signaling markedly decreases the anchorage-independent survival of HeLa cells in soft agar and in athymic mice. Last, we confirm the relative importance of phosphatidic acid for this pro-survival effect as phosphatidic acid supplementation fully restores MAPK signaling and partially rescues HeLa cells from choline kinase inhibition. Taken together, these data indicate that the pooling of phosphocholine in cancer cells may be required to provide a ready supply of phosphatidic acid necessary for the feed-forward amplification of cancer survival signaling pathways.
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Contractor KB, Kenny LM, Stebbing J, Al-Nahhas A, Palmieri C, Sinnett D, Lewis JS, Hogben K, Osman S, Shousha S, Lowdell C, Coombes RC, Aboagye EO. [11C]choline positron emission tomography in estrogen receptor-positive breast cancer. Clin Cancer Res 2009; 15:5503-10. [PMID: 19706823 DOI: 10.1158/1078-0432.ccr-09-0666] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Novel radiotracers could potentially allow the identification of clinically aggressive tumor phenotypes. As choline metabolism increases during malignant transformation and progression of human mammary epithelial cells, we examined the ability of [(11)C]choline (CHO) positron emission tomography imaging to detect clinically aggressive phenotype in patients with estrogen receptor (ER)-positive breast cancer in vivo. EXPERIMENTAL DESIGN CHO positron emission tomography was done in 32 individuals with primary or metastatic ER-positive breast cancer. Semiquantitative (standardized uptake value) and fully quantitative (net irreversible transfer rate constant of CHO, Ki) estimates of CHO uptake in the tumors were calculated and compared with tumor grade, size, involved nodes, and also ER, progesterone receptor, Ki-67, and human epidermal growth factor receptor-2 scores. RESULTS Breast tumors were well visualized in 30 of 32 patients with good tumor background ratios. A wide range of uptake values were observed in primary and metastatic tumors. CHO uptake variables correlated well with tumor grade. For most imaging variables, a poor association was found with tumor size, ER, progesterone receptor, human epidermal growth factor receptor-2, Ki-67, and nodal status. CONCLUSIONS CHO showed good uptake in most breast cancers and merits further investigation as a breast cancer imaging agent.
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Pharmacodynamic markers for choline kinase down-regulation in breast cancer cells. Neoplasia 2009; 11:477-84. [PMID: 19412432 DOI: 10.1593/neo.81430] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2008] [Revised: 02/11/2009] [Accepted: 02/12/2009] [Indexed: 12/19/2022] Open
Abstract
High levels of choline kinase (ChoK) expression and choline phospholipid metabolites are often associated with malignant transformation, invasion, and metastasis, particularly in breast cancer. These findings have led to the development of novel pharmacologic or gene therapeutic interventions for ChoK-targeted inhibition. To identify pharmacodynamic markers for the therapeutic evaluation of ChoK down-regulation, we investigated the uptake and efflux of [(3)H]choline, a natural substrate of ChoK, and two other important metabolic indicators of malignancy, namely, [(3)H]thymidine and [(3)H]fluorodeoxyglucose, which measure proliferation and glucose metabolic changes, respectively, in ChoK-downregulated cells. Choline uptake in nonmalignant and malignant breast epithelial cell lines expressing graded levels of ChoK showed a ChoK-dependent uptake, retention, and efflux of [(3)H]choline. Reduced proliferation observed because of ChoK down-regulation resulted in reduced [(3)H]thymidine uptake and incorporation into DNA within 48 hours of treatment. Reduced [(3)H]thymidine incorporation levels were consistent with a decreased cell cycle S-phase fraction. No change in [(3)H]fluorodeoxyglucose uptake was observed between ChoK-downregulated and control cells in any of the three cell lines tested. These results demonstrate the utility of radiolabeled choline or choline analogs and proliferation imaging agents as pharmacodynamic markers for ChoK-targeted therapies and suggest a ChoK-mediated mechanism for tumor sequestration of choline-based imaging agents.
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Gibellini F, Hunter WN, Smith TK. The ethanolamine branch of the Kennedy pathway is essential in the bloodstream form of Trypanosoma brucei. Mol Microbiol 2009; 73:826-43. [PMID: 19555461 PMCID: PMC2784872 DOI: 10.1111/j.1365-2958.2009.06764.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Phosphatidylethanolamine (GPEtn), a major phospholipid component of trypanosome membranes, is synthesized de novo from ethanolamine through the Kennedy pathway. Here the composition of the GPEtn molecular species in the bloodstream form of Trypanosoma brucei is determined, along with new insights into phospholipid metabolism, by in vitro and in vivo characterization of a key enzyme of the Kennedy pathway, the cytosolic ethanolamine-phosphate cytidylyltransferase (TbECT). Gene knockout indicates that TbECT is essential for growth and survival, thus highlighting the importance of the Kennedy pathway for the pathogenic stage of the African trypanosome. Phosphatiylserine decarboxylation, a potential salvage pathway, does not appear to be active in cultured bloodstream form T. brucei, and it is not upregulated even when the Kennedy pathway is disrupted. In vivo metabolic labelling and phospholipid composition analysis by ESI-MS/MS of the knockout cells confirmed a significant decrease in GPEtn species, as well as changes in the relative abundance of other phospholipid species. Reduction in GPEtn levels had a profound influence on the morphology of the mutants and it compromised mitochondrial structure and function, as well as glycosylphosphatidylinositol anchor biosynthesis. TbECT is therefore genetically validated as a potential drug target against the African trypanosome.
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Affiliation(s)
- Federica Gibellini
- Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, Scotland, UK
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Hernando E, Sarmentero-Estrada J, Koppie T, Belda-Iniesta C, Ramírez de Molina V, Cejas P, Ozu C, Le C, Sánchez JJ, González-Barón M, Koutcher J, Cordón-Cardó C, Bochner BH, Lacal JC, Ramírez de Molina A. A critical role for choline kinase-alpha in the aggressiveness of bladder carcinomas. Oncogene 2009; 28:2425-35. [PMID: 19448670 DOI: 10.1038/onc.2009.91] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Bladder cancer is one of the most common causes of death in industrialized countries. New tumor markers and therapeutic approaches are still needed to improve the management of bladder cancer patients. Choline kinase-alpha (ChoKalpha) is a metabolic enzyme that has a role in cell proliferation and transformation. Inhibitors of ChoKalpha show antitumoral activity and are expected to be introduced soon in clinical trials. This study aims to assess whether ChoKalpha plays a role in the aggressiveness of bladder tumors and constitutes a new approach for bladder cancer treatment. We show here that ChoKalpha is constitutively altered in human bladder tumor cells. Furthermore, in vivo murine models, including an orthotopic model to mimic as much as possible the physiological conditions, revealed that increased levels of ChoKalpha potentiate both tumor formation (P< or =0.0001) and aggressiveness of the disease on different end points (P=0.011). Accordingly, increased levels of ChoKalpha significantly reduce survival of mice with bladder cancer (P=0.05). Finally, treatment with a ChoKalpha-specific inhibitor resulted in a significant inhibition of tumor growth (P=0.02) and in a relevant increase in survival (P=0.03).
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Affiliation(s)
- E Hernando
- Molecular Pathology, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
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67
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Krishnamachary B, Glunde K, Wildes F, Mori N, Takagi T, Raman V, Bhujwalla ZM. Noninvasive detection of lentiviral-mediated choline kinase targeting in a human breast cancer xenograft. Cancer Res 2009; 69:3464-71. [PMID: 19336572 DOI: 10.1158/0008-5472.can-08-4120] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Elevated phosphocholine (PC) and total choline (tCho) metabolites are widely established characteristics of most cancer cells, including breast cancer. Effective silencing of choline kinase (chk), the enzyme that converts choline to PC, is associated with reduced tumor growth. The functional importance and down-regulation of chk using RNA interference has been previously established. Here, we report on the preclinical evaluation of lentiviral vector-mediated down-regulation of chk using short hairpin RNA (shRNA) in established tumors derived from human breast cancer cells. Concentrated lentivirus expressing shRNA against chk was injected i.v. in the tail vein of MDA-MB-231 tumor-bearing female severe combined immunodeficient mice. Transduction efficiency in cells and tumors in vivo was assessed optically by enhanced green fluorescent protein expression and additionally from chk mRNA and protein levels. An 80% reduction in chk mRNA and protein was achieved following approximately 90% transduction efficiency in cells. After transduction with chk-shRNA, (1)H magnetic resonance spectroscopy (MRS) of cell and tumor extracts showed decreases in PC and tCho levels (P < 0.01 and 0.05, respectively) in comparison with controls. PC levels were monitored noninvasively by (31)P MRS in tumors and by (1)H MRS in cell and tumor tissue extracts. Noninvasive (31)P MR spectra of chk-shRNA-transduced tumors in vivo showed lower PC and phosphomonoester levels that were associated with reduced tumor growth and proliferation. This study shows the use of lentiviral vectors to target chk in a human breast cancer xenograft and noninvasive MRS detection of this targeting.
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Affiliation(s)
- Balaji Krishnamachary
- Johns Hopkins University In Vivo Cellular Molecular Imaging Center Program, The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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68
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Srivani P, Sastry GN. Potential choline kinase inhibitors: a molecular modeling study of bis-quinolinium compounds. J Mol Graph Model 2008; 27:676-88. [PMID: 19147382 DOI: 10.1016/j.jmgm.2008.10.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2008] [Revised: 10/10/2008] [Accepted: 10/27/2008] [Indexed: 11/19/2022]
Abstract
Choline kinase (ChoK) is reported to involve in cell signaling pathways and cell growth by regulating the intermediate, phosphocholine (PCho), which is the first step to biosynthesis a membrane phospholipid, phosphatidylcholine. The PCho levels are overexpressed due to elevated activation of the protein under carcinogenesis conditions. ChoK has thus evolved as a novel target for various cancers and a range of compounds has been reported in this course as potent ChoK inhibitors. However, not much information is known about the binding site of the inhibitors. Therefore, we ventured to unravel the possible binding site of 39 bis-quinolinium inhibitors from which the structural requirement for better protein-ligand complex was delved. Molecular docking and 3D-QSAR studies namely comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) were performed on the series. The knowledge of the active site was obtained from the site id search and molcad surface calculations of Sybyl, which was further considered for docking studies. In 3D-QSAR, the best predictions were obtained from the model where 29 compounds were considered in the training set and remaining 10 in the test set. The best CoMFA statistics were obtained with r(2) of 0.99 and q(2) of 0.81 while, CoMSIA was resulted with r(2) of 0.98 and q(2) of 0.77. A comparative analysis was done with the resulted 3D-QSAR maps and the docked poses by overlaying the maps on the active site residues. Since, there is no reported ligand co-crystallized structure of ChoK the present study provides valuable clues on the binding conformation of the ligand and its interactions with the active site.
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Affiliation(s)
- P Srivani
- Molecular Modeling Group, Organic Chemical Sciences, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500007, India
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69
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Jellinek M. The need for a multi-level biochemical approach to defeat cancer that will also support the host. Med Hypotheses 2008; 71:515-26. [PMID: 18752905 DOI: 10.1016/j.mehy.2008.05.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2008] [Revised: 05/16/2008] [Accepted: 05/19/2008] [Indexed: 10/21/2022]
Abstract
Cited research papers support the main hypothesis that selected publications supply sufficient information for a combined multi-level treatment strategy against cancer that will also strengthen the host. The three major elements of the proposal are: (A) metastasis being separate from tumor growth requires specific antimetastatic treatments. For this, manipulation of the composition of phospholipids will alter cellular charge characteristics which are instrumental in adhesion. (B) Formate metabolism is at the center of many activities that are controlling tumor growth. The rational and consequences of this are as follows. Supply of formate depends mainly on serine, and consumption on conversion to CO2 yielding needed NADPH. The remainder is used to complete IMP configuration with 5-aminoimidazole-4-carboxamide ribonucleotide (ZMP). At homeostasis residual ZMP activates AMP-activated protein kinase (AMPK) to curb growth promoting phosphatidylinositol-3-kinase (PI3PK). Residual ZMP also activates the oxidation of choline to betaine supplying methyl groups needed for global methylation of DNA while increased oxidation of choline also alters cellular phospholipid composition (refer to metastasis). At low formate level, increased accumulated ZMP becomes pyrophosporylated to ZTP. AMPK activation shifts to PI3PK activity for insulin action restoring formate supplied by serine derived from glycolysis. Increased NADPH-generating glucose-6-phosphate dehydrogenase is diminishing NADP+ required for dehydrogenation of formate. This is restoring the formate balance while lowering ZMP levels to that of homeostasis. Evidence suggests that transformed cells exceed up-regulation of formate thus suppressing all ZMP accumulations resulting in limited AMPK activation, cessation of choline oxidation to betaine and loss of global methylation of DNA. This scenario appears to be tied to tumor survival, a state that could be altered by metabolic interventions using mild agents as described in the research reports cited. (C) Because of a preponderance of pyrimidines in cancer supporting UTP requiring immune evasion, exogenous IMP may offset this imbalance and thus hinder tumor anti-immune activities while strengthen host immune functions. For studies to confirm the proposal, the overall expected result is that a combined administration of all these agents cited here will outperform any single agent considered so far for anticancer treatment.
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Affiliation(s)
- Max Jellinek
- The Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University, 1402 South Grand Boulevard, St. Louis, MO 63104, United States.
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Schöder H, Ong SC. Fundamentals of molecular imaging: rationale and applications with relevance for radiation oncology. Semin Nucl Med 2008; 38:119-28. [PMID: 18243847 DOI: 10.1053/j.semnuclmed.2007.11.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Molecular imaging allows for the visualization and quantification biologic processes at cellular levels. This article focuses on positron emission tomography as one readily available tool for clinical molecular imaging. To prove its clinical utility in oncology, molecular imaging will ultimately have to provide valuable information in the following 4 pertinent areas: staging; assessment of extent of disease; target delineation for radiation therapy planning; response prediction and assessment and differentiation between treatment sequelae and recurrent disease. These issues are addressed in other contributions in this issue of Seminars in Nuclear Medicine. In contrast, this article will focus on the biochemical principles of cancer metabolism that provide the rationale for positron emission tomography imaging in radiation oncology.
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Affiliation(s)
- Heiko Schöder
- Department of Radiology/Nuclear Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
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71
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Soto A, Carman GM. Regulation of the Saccharomyces cerevisiae CKI1-encoded choline kinase by zinc depletion. J Biol Chem 2008; 283:10079-88. [PMID: 18276583 DOI: 10.1074/jbc.m800502200] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In the yeast Saccharomyces cerevisiae, the CKI1-encoded choline kinase catalyzes the committed step in the synthesis of phosphatidylcholine via the CDP-choline branch of the Kennedy pathway. Analysis of a P(CKI1)-lacZ reporter gene revealed that CKI1 expression was regulated by intracellular levels of the essential mineral zinc. Zinc depletion resulted in a concentration-dependent induction of CKI1 expression. This regulation was mediated by the zinc-sensing and zinc-inducible transcriptional activator Zap1p. A purified Zap1p probe interacted with two putative UAS(ZRE) sequences (ZRE1 and ZRE2) in the CKI1 promoter. Mutations of ZRE1 and ZRE2 to a nonconsensus UAS(ZRE) attenuated the induction of CKI1 expression in response to zinc depletion. A UAS(INO) element in the CKI1 promoter was responsible for stimulating CKI1 expression, but this element was not involved with the regulation by zinc depletion. The induction of CKI1 expression in zinc-depleted cells translated into increased choline kinase activity in vitro and in vivo, and an increase in phosphatidylcholine synthesis via the Kennedy pathway.
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Affiliation(s)
- Aníbal Soto
- Department of Food Science and Rutgers Center for Lipid Research, Rutgers University, New Brunswick, NJ 08901, USA
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72
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Ramírez de Molina A, Sarmentero-Estrada J, Belda-Iniesta C, Tarón M, Ramírez de Molina V, Cejas P, Skrzypski M, Gallego-Ortega D, de Castro J, Casado E, García-Cabezas MA, Sánchez JJ, Nistal M, Rosell R, González-Barón M, Lacal JC. Expression of choline kinase alpha to predict outcome in patients with early-stage non-small-cell lung cancer: a retrospective study. Lancet Oncol 2007; 8:889-97. [PMID: 17851129 DOI: 10.1016/s1470-2045(07)70279-6] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
BACKGROUND Adequate prognostic markers to predict outcome of patients with lung cancer are still needed. The aim of this study was to assess whether choline kinase alpha (ChoKalpha) gene expression could identify patients with different prognoses. ChoKalpha is an enzyme involved in cell metabolism and proliferation and has a role in oncogene-mediated transformation in several human tumours, including lung cancer. METHODS 60 patients with non-small-cell lung cancer (NSCLC) who had undergone surgical resection in a single centre were enrolled into the study as the training group. We used real-time reverse-transcriptase PCR (RT-PCR) to measure ChoKalpha gene expression and analyse the association between ChoKalpha expression and survival in evaluable patients. Additionally, a second group of 120 patients with NSCLC from a different hospital were enrolled into the study as the validation group. We did an overall analysis of all 167 patients who had available tissue to confirm the cut-off point for future studies. The primary endpoints were lung-cancer-specific survival and relapse-free survival. FINDINGS Seven of the 60 patients in the training group were not evaluable due to insufficient tissue. In the 53 evaluable patients, the cut-off for those with ChoKalpha overexpression was defined by receiver operator under the curve (ROC) methodology. 4-year lung-cancer-specific survival was 54.43% (95% CI 28.24-80.61) for 25 patients with ChoKalpha expression above the ROC-defined cut-off compared with 88.27% (75.79-100) for 28 patients with concentrations of the enzyme below this cut-off (hazard ratio [HR] 3.14 [0.83-11.88], p=0.07). In the validation group, six of the 120 enrolled patients were not evaluable due to insufficient tissue. For the other 114 patients, 4-year lung-cancer-specific survival was 46.66% (32.67-59.65) for those with ChoKalpha expression above the ROC-defined cut-off compared with 67.01% (50.92-81.11) for patients with concentrations of ChoKalpha below the cut-off (HR 1.87 [1.01-3.46], p=0.04). A global analysis of all 167 patients further confirmed the association between ChoKalpha overexpression and worse clinical outcome of patients with NSCLC: 4-year lung-cancer-specific survival for ChoKalpha expression above the ROC-defined cut-off was 49.00% (36.61-60.38) compared with 70.52% (59.80-76.75) for those with concentrations of ChoKalpha below the cut-off (HR 1.98 [1.14-3.45], p=0.01). The overall analysis confirmed the cut-off for ChoKalpha expression should be 1.91-times higher than concentrations noted in healthy tissues when ChoKalpha is used as an independent predictive factor of relapse-free and lung-cancer-specific survival in patients with early-stage NSCLC. INTERPRETATION ChoKalpha expression is a new prognostic factor that could be used to help identify patients with early-stage NSCLC who might be at high risk of recurrence, and to identify patients with favourable prognosis who could receive less aggressive treatment options or avoid adjuvant systemic treatment. New treatments that inhibit ChoKalpha expression or activity in patients with lung cancer should be studied further.
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Affiliation(s)
- Ana Ramírez de Molina
- Translational Oncology Unit, CSIC-UAM-La Paz, National Center of Biotechnology, Madrid, Spain
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Aoyama C, Ishidate K, Sugimoto H, Vance DE. Induction of choline kinase alpha by carbon tetrachloride (CCl4) occurs via increased binding of c-jun to an AP-1 element. Biochim Biophys Acta Mol Cell Biol Lipids 2007; 1771:1148-55. [PMID: 17728180 DOI: 10.1016/j.bbalip.2007.07.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2006] [Revised: 06/30/2007] [Accepted: 07/14/2007] [Indexed: 10/23/2022]
Abstract
The mechanism by which treatment of mice with CCl4 induces an increase in choline kinase alpha has been investigated. Nuclear run on assays demonstrated a major increase in the transcript for choline kinase alpha in livers from mice 3 h and 6 h after administration of CCl4 compared to vehicle (olive oil). 5'deletion analyses of choline kinase alpha promoter-luciferase constructs expressed in Hepa-1 cells identified a promoter element between -875 and -866 that was nearly identical to an AP-1 consensus site. Mutation of this AP-1 site caused a striking decrease in the expression of choline kinase alpha promoter-luciferase constructs. Electromobility shift assays with nuclear extracts from mouse liver demonstrated that c-Jun, but not c-fos, bound oligonucleotides with the AP-1 site. The amount of c-jun bound was greatly increased when hepatic nuclear extracts from mice treated with CCl4 were used. Chromatin immunoprecipitation assays confirmed that c-jun binds to the choline kinase alpha promoter. The results from these studies provide strong evidence that the choline kinase alpha promoter has a distal element (-875/-867) that binds c-jun and the binding of c-jun is enhanced by treatment with CCl4.
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Affiliation(s)
- Chieko Aoyama
- Department of Biochemistry and the Canadian Institutes of Health Research Group on Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada T6G 2S2.
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74
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Glunde K, Jacobs MA, Bhujwalla ZM. Choline metabolism in cancer: implications for diagnosis and therapy. Expert Rev Mol Diagn 2007; 6:821-9. [PMID: 17140369 DOI: 10.1586/14737159.6.6.821] [Citation(s) in RCA: 146] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Magnetic resonance studies from the last 10 years have conclusively demonstrated that choline metabolism is altered in a wide variety of cancers. In cancer, the choline metabolite profile is characterized by an elevation of phosphocholine and total choline-containing compounds. This elevation is increasingly being used as an endogenous biomarker of cancer. Importantly, the enzymes and pathways resulting in these distinct alterations in phosphocholine and total choline may provide novel molecular targets for specific, targeted anticancer therapies. In this article, we have summarized some of the magnetic resonance spectroscopy and positron emission tomography techniques that are currently available, or will be in the near future, for choline metabolism-based diagnosis, staging and therapy assessment in cancer patients. This review also outlines currently known molecular alterations that cause the aberrant choline metabolite profile in cancers and concludes with a summary of recent research findings that may, in the future, lead to novel anticancer therapies targeting choline metabolism.
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Affiliation(s)
- Kristine Glunde
- The Johns Hopkins University School of Medicine, Russell H. Morgan Department of Radiology & Radiological Sciences and Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD 21205, USA.
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75
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Eliyahu G, Kreizman T, Degani H. Phosphocholine as a biomarker of breast cancer: Molecular and biochemical studies. Int J Cancer 2007; 120:1721-30. [PMID: 17236204 DOI: 10.1002/ijc.22293] [Citation(s) in RCA: 169] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The discovery of metabolic and molecular markers that help improving the detection and diagnosis of breast cancer is an important goal to be achieved. A high composite-choline signal in magnetic resonance spectra of breast lesions has been demonstrated to improve the accuracy of breast cancer diagnosis. In the present study we revealed the principal molecular and biochemical steps associated with the induction of choline metabolism and phosphocholine accumulation in human breast cancer cell-lines in comparison with normal human mammary epithelial cells. We found upregulation of the expression levels of specific choline transporters: organic cation transporter-2 and choline high affinity transporter-1, as well as of the enzyme choline kinase alpha in the cancerous cells in comparison with that in the normal mammary epithelial cells. The expression levels of choline transporter like-1, organic cation transporter-1 and choline kinase beta were similar in normal and cancerous cells. We further showed that choline transport rates and choline kinase activity indeed increased by several fold in the cancer cells leading to the elevation of phosphocholine. The results strongly suggest that phosphocholine can serve as a biomarker of breast cancer reflecting upregulation of specific choline transporters and choline kinase genes.
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Affiliation(s)
- Galit Eliyahu
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel
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76
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Glunde K, Ackerstaff E, Mori N, Jacobs MA, Bhujwalla ZM. Choline phospholipid metabolism in cancer: consequences for molecular pharmaceutical interventions. Mol Pharm 2007; 3:496-506. [PMID: 17009848 DOI: 10.1021/mp060067e] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Over the past decade, our program has focused on understanding the role of the physiological environment, tumor vasculature, and metabolism in several of the aggressive phenotypic traits of cancer, such as invasion and metastasis. These studies have been performed primarily with magnetic resonance (MR) imaging (MRI) and spectroscopy (MRS) on human breast and prostate cancer models. During the course of these studies, we observed specific changes in choline phospholipid metabolism associated with a more aggressive phenotype. Molecular or pharmacologic interventions that reduced this aggressiveness were also consistent with a reversal of these alterations. In this contextual review, we have outlined the insight we have gained from these studies and have discussed some of the enzymes and pathways that may present novel targets for pharmaceutical interventions in cancer.
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Affiliation(s)
- Kristine Glunde
- JHU ICMIC Program, The Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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77
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Unschuld PG, Dächsel J, Darios F, Kohlmann A, Casademunt E, Lehmann-Horn K, Dichgans M, Ruberg M, Brice A, Gasser T, Lücking CB. Parkin modulates gene expression in control and ceramide-treated PC12 cells. Mol Biol Rep 2007; 33:13-32. [PMID: 16636914 DOI: 10.1007/s11033-005-3961-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/03/2005] [Indexed: 11/26/2022]
Abstract
Mutations in the parkin gene cause autosomal-recessive early-onset parkinsonism as a result of the degeneration of mesencephalic dopaminergic neurons. In cell culture models, parkin expression has been shown to protect against cell death mediated by the sphingolipid ceramide. To determine whether the antiapoptotic effect of parkin involves changes in gene expression, we used Affymetrix oligonucleotide microarrays to analyse gene expression in stably transfected PC12 cells which conditionally overexpress parkin, that were treated or not with C2-ceramide. Overexpression of parkin and ceramide treatment both modulated gene expression. A number of the genes upregulated in the presence of ceramide, and modulated by parkin, were associated with apoptosis or cellular stress reactions. We validated the upregulation of four such genes (CHK, EIF4EBP1, GADD45A and PTPN-5) by real-time PCR after 3, 6, 9 and 12 h of ceramide treatment in cells that overexpressed parkin or not. All were upregulated 2 to 11-fold, 3 and 6 h after application of ceramide. Parkin overexpression reduced the upregulation of EIF4EBP1, GADD45A and PTPN-5, but only at 6 h. These results suggest that, in this assay, the cytoprotective effect of parkin might result not only from its E3-ligase activity, but also from direct or indirect modulation of gene expression in a time-dependent manner.
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Affiliation(s)
- P G Unschuld
- Klinik für Neurologie, Ludwig-Maximilians-Universität, Marchioninistr. 15, 81377, München, Germany
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78
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Choubey V, Maity P, Guha M, Kumar S, Srivastava K, Puri SK, Bandyopadhyay U. Inhibition of Plasmodium falciparum choline kinase by hexadecyltrimethylammonium bromide: a possible antimalarial mechanism. Antimicrob Agents Chemother 2006; 51:696-706. [PMID: 17145794 PMCID: PMC1797733 DOI: 10.1128/aac.00919-06] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Choline kinase is the first enzyme in the Kennedy pathway (CDP-choline pathway) for the biosynthesis of the most essential phospholipid, phosphatidylcholine, in Plasmodium falciparum. In addition, choline kinase also plays a pivotal role in trapping essential polar head group choline inside the malaria parasite. Recently, Plasmodium falciparum choline kinase (PfCK) has been cloned, overexpressed, and purified. However, the function of this enzyme in parasite growth and survival has not been evaluated owing to the lack of a suitable inhibitor. Purified recombinant PfCK enabled us to identify an inhibitor of PfCK, hexadecyltrimethylammonium bromide (HDTAB), which has a very close structural resemblance to hexadecylphosphocholine (miltefosin), the well-known antiproliferative and antileishmanial drug. HDTAB inhibited PfCK in a dose-dependent manner and offered very potent antimalarial activity in vitro against Plasmodium falciparum. Moreover, HDTAB exhibited profound antimalarial activity in vivo against the rodent malaria parasite Plasmodium yoelii (N-67 strain). Interestingly, parasites at the trophozoite and schizont stages were found to be particularly sensitive to HDTAB. The stage-specific antimalarial effect of HDTAB correlated well with the expression pattern of PfCK in P. falciparum, which was observed by reverse transcription-PCR and immunofluorescence microscopy. Furthermore, the antimalarial activity of HDTAB paralleled the decrease in phosphatidylcholine content, which was found to correlate with the decreased phosphocholine generation. These results suggest that inhibition of choline kinase by HDTAB leads to decreased phosphocholine, which in turn causes a decrease in phosphatidylcholine biosynthesis, resulting in death of the parasite.
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Affiliation(s)
- Vinay Choubey
- Division of Drug Target Discovery and Development, Central Drug Research Institute, Chatter Manzil Palace, Lucknow, Uttar Pradesh, India
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79
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Glunde K, Serkova NJ. Therapeutic targets and biomarkers identified in cancer choline phospholipid metabolism. Pharmacogenomics 2006; 7:1109-23. [PMID: 17054420 DOI: 10.2217/14622416.7.7.1109] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Choline phospholipid metabolism is altered in a wide variety of cancers. The choline metabolite profile of tumors and cancer cells is characterized by an elevation of phosphocholine and total choline-containing compounds. Noninvasive magnetic resonance spectroscopy can be used to detect this elevation as an endogenous biomarker of cancer, or as a predictive biomarker for monitoring tumor response to novel targeted therapies. The enzymes directly causing this elevation, such as choline kinase, phospholipase C and phospholipase D may provide molecular targets for anticancer therapies. Signal transduction pathways that are activated in cancers, such as those mediated by the receptor tyrosine kinases breakpoint cluster region-abelson (Bcr-Abl), c-KIT or epidermal growth factor receptor (EGFR), correlate with the alterations in choline phospholipid metabolism of cancers, and also offer molecular targets for specific anticancer therapies. This review summarizes recently discovered molecular targets in choline phospholipid metabolism and signal transduction pathways, which may lead to novel anticancer therapies potentially being monitored by magnetic resonance spectroscopy techniques.
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Affiliation(s)
- Kristine Glunde
- The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, 720 Rutland Avenue, 212 Traylor Building Baltimore, MD 21205, USA.
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80
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Malito E, Sekulic N, Too WCS, Konrad M, Lavie A. Elucidation of human choline kinase crystal structures in complex with the products ADP or phosphocholine. J Mol Biol 2006; 364:136-51. [PMID: 17007874 PMCID: PMC1885479 DOI: 10.1016/j.jmb.2006.08.084] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2006] [Revised: 08/25/2006] [Accepted: 08/28/2006] [Indexed: 10/24/2022]
Abstract
Choline kinase, responsible for the phosphorylation of choline to phosphocholine as the first step of the CDP-choline pathway for the biosynthesis of phosphatidylcholine, has been recognized as a new target for anticancer therapy. Crystal structures of human choline kinase in its apo, ADP and phosphocholine-bound complexes, respectively, reveal the molecular details of the substrate binding sites. ATP binds in a cavity where residues from both the N and C-terminal lobes contribute to form a cleft, while the choline-binding site constitutes a deep hydrophobic groove in the C-terminal domain with a rim composed of negatively charged residues. Upon binding of choline, the enzyme undergoes conformational changes independently affecting the N-terminal domain and the ATP-binding loop. From this structural analysis and comparison with other kinases, and from mutagenesis data on the homologous Caenorhabditis elegans choline kinase, a model of the ternary ADP.phosphocholine complex was built that reveals the molecular basis for the phosphoryl transfer activity of this enzyme.
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Affiliation(s)
- Enrico Malito
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois, 60607
| | - Nikolina Sekulic
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois, 60607
| | - Wei Cun See Too
- Department of Molecular Genetics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany, D-37077
| | - Manfred Konrad
- Department of Molecular Genetics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany, D-37077
| | - Arnon Lavie
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois, 60607
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81
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Hara T, Bansal A, DeGrado TR. Choline Transporter as a Novel Target for Molecular Imaging of Cancer. Mol Imaging 2006. [DOI: 10.2310/7290.2006.00032] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Toshihiko Hara
- From the Department of Radiology, Indiana University School of Medicine, Indianapolis, IN
| | - Aditya Bansal
- From the Department of Radiology, Indiana University School of Medicine, Indianapolis, IN
| | - Timothy R. DeGrado
- From the Department of Radiology, Indiana University School of Medicine, Indianapolis, IN
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82
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Janardhan S, Srivani P, Sastry G. 2D and 3D Quantitative Structure-Activity Relationship Studies on a Series ofbis-Pyridinium Compounds as Choline Kinase Inhibitors. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/qsar.200530199] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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83
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Choubey V, Guha M, Maity P, Kumar S, Raghunandan R, Maulik PR, Mitra K, Halder UC, Bandyopadhyay U. Molecular characterization and localization of Plasmodium falciparum choline kinase. Biochim Biophys Acta Gen Subj 2006; 1760:1027-38. [PMID: 16626864 DOI: 10.1016/j.bbagen.2006.03.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2005] [Revised: 02/24/2006] [Accepted: 03/01/2006] [Indexed: 10/24/2022]
Abstract
Generation of phosphocholine by choline kinase is important for phosphatidylcholine biosynthesis via Kennedy pathway and phosphatidylcholine biosynthesis is essential for intraerythrocytic growth of malaria parasite. A putative gene (Gene ID PF14_0020) in chromosome 14, having highest sequence homology with choline kinase, has been identified by BLAST searches from P. falciparum genome sequence database. This gene has been PCR amplified, cloned, over-expressed and characterized. Choline kinase activity of the recombinant protein (PfCK) was validated as it catalyzed the formation of phosphocholine from choline in presence of ATP. The K(m) values for choline and ATP are found to be 145+/-20 microM and 2.5+/-0.3 mM, respectively. PfCK can phosphorylate choline efficiently but not ethanolamine. Southern blotting indicates that PfCK is a single copy gene and it is a cytosolic protein as evidenced by Western immunoblotting and confocal microscopy. A model structure of PfCK was constructed based on the crystal structure of choline kinase of C. elegans to search the structural homology. Consistent with the homology modeling predictions, CD analysis indicates that the alpha and beta content of PfCK are 33% and 14%, respectively. Since choline kinase plays a vital role for growth and multiplication of P. falciparum during intraerythrocytic stages, we can suggest that this well characterized PfCK may be exploited in the screening of new choline kinase inhibitors to evaluate their antimalarial activity.
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Affiliation(s)
- Vinay Choubey
- Division of Drug Target Discovery and Development, Central Drug Research Institute, Chatter Manzil Palace, Mahatma Gandhi Marg, Lucknow-226001, Uttar Pradesh, India
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84
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Spaeth N, Wyss MT, Pahnke J, Biollaz G, Lutz A, Goepfert K, Westera G, Treyer V, Weber B, Buck A. Uptake of 18F-fluorocholine, 18F-fluoro-ethyl-L-tyrosine and 18F-fluoro-2-deoxyglucose in F98 gliomas in the rat. Eur J Nucl Med Mol Imaging 2006; 33:673-82. [PMID: 16538503 DOI: 10.1007/s00259-005-0045-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2005] [Accepted: 11/16/2005] [Indexed: 10/24/2022]
Abstract
INTRODUCTION The positron emission tomography (PET) tracers (18)F-fluoro-ethyl-L: -tyrosine (FET), (18)F-fluorocholine (N,N-dimethyl-N-[(18)F]fluoromethyl-2-hydroxyethylammonium (FCH]) and (18)F-fluoro-2-deoxyglucose (FDG) are used in the diagnosis of brain tumours. The aim of this study was threefold: (a) to assess the uptake of the different tracers in the F98 rat glioma, (b) to evaluate the impact of blood-brain barrier (BBB) disruption and microvessel density (MVD) on tracer uptake and (c) to compare the uptake in the tumours to that in the radiation injuries (induced by proton irradiation of healthy rats) of our previous study. METHODS F98 gliomas were induced in 26 rats. The uptake of FET, FCH and FDG was measured using autoradiography and correlated with histology, disruption of the BBB and MVD. RESULTS The mean FET, FCH and FDG standardised uptake values (SUVs) in the tumour and the contralateral normal cortex (in parentheses) were 4.19+/-0.86 (1.32+/-0.26), 2.98+/-0.58 (0.51+/-0.11) and 11.02+/-3.84 (4.76+/-1.77) respectively. MVD was significantly correlated only with FCH uptake. There was a trend towards a negative correlation between the degree of BBB disruption and FCH uptake and a trend towards a positive correlation with FET uptake. The ratio of the uptake in tumours to that in the radiation injuries was 1.97 (FCH), 2.71 (FET) and 2.37 (FDG). CONCLUSION MVD displayed a significant effect only on FCH uptake. The degree of BBB disruption seems to affect the accumulation of FET and FCH, but not FDG. Mean tumour uptake for all tracers was significantly higher than the accumulation in radiation injuries.
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Affiliation(s)
- Nicolas Spaeth
- PET Center, Division of Nuclear Medicine, University Hospital, Rämistrasse 100, 8091, Zürich, Switzerland
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85
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Glunde K, Raman V, Mori N, Bhujwalla ZM. RNA interference-mediated choline kinase suppression in breast cancer cells induces differentiation and reduces proliferation. Cancer Res 2006; 65:11034-43. [PMID: 16322253 DOI: 10.1158/0008-5472.can-05-1807] [Citation(s) in RCA: 145] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Choline kinase is overexpressed in breast cancer cells and activated by oncogenes and mitogenic signals, making it a potential target for cancer therapy. Here, we have examined, for the first time, the effects of RNA interference (RNAi)-mediated down-regulation of choline kinase in nonmalignant and malignant human breast epithelial cell lines using magnetic resonance spectroscopy (MRS) as well as molecular analyses of proliferation and differentiation markers. RNAi knockdown of choline kinase reduced proliferation, as detected by proliferating cell nuclear antigen and Ki-67 expression, and promoted differentiation, as detected by cytosolic lipid droplet formation and expression of galectin-3. The functional importance of RNAi-mediated choline kinase down-regulation on choline phospholipid metabolism was confirmed by the significant reduction of phosphocholine detected by MRS. These results strongly support the targeting of choline kinase in breast cancer cells with RNAi and show the potential ability of noninvasive MRS to detect and evaluate future treatments incorporating such strategies.
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Affiliation(s)
- Kristine Glunde
- John Hopkins University In Vivo Cellular Molecular Imaging Center Program, Russell H. Morgan Department of Radiology and Radiological Science, John Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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86
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Al-Saffar NMS, Troy H, Ramírez de Molina A, Jackson LE, Madhu B, Griffiths JR, Leach MO, Workman P, Lacal JC, Judson IR, Chung YL. Noninvasive Magnetic Resonance Spectroscopic Pharmacodynamic Markers of the Choline Kinase Inhibitor MN58b in Human Carcinoma Models. Cancer Res 2006; 66:427-34. [PMID: 16397258 DOI: 10.1158/0008-5472.can-05-1338] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
MN58b is a novel anticancer drug that inhibits choline kinase, resulting in inhibition of phosphocholine synthesis. The aim of this work was to develop a noninvasive and robust pharmacodynamic biomarker for target inhibition and, potentially, tumor response following MN58b treatment. Human HT29 (colon) and MDA-MB-231 (breast) carcinoma cells were examined by proton (1H) and phosphorus (31P) magnetic resonance spectroscopy (MRS) before and after treatment with MN58b both in culture and in xenografts. An in vitro time course study of MN58b treatment was also carried out in MDA-MB-231 cells. In addition, enzymatic assays of choline kinase activity in cells were done. A decrease in phosphocholine and total choline levels (P < 0.05) was observed in vitro in both cell lines after MN58b treatment, whereas the inactive analogue ACG20b had no effect. In MDA-MB-231 cells, phosphocholine fell significantly as early as 4 hours following MN58b treatment, whereas a drop in cell number was observed at 48 hours. Significant correlation was also found between phosphocholine levels (measured by MRS) and choline kinase activities (r2 = 0.95, P = 0.0008) following MN58b treatment. Phosphomonoesters also decreased significantly (P < 0.05) in both HT29 and MDA-MB-231 xenografts with no significant changes in controls. 31P-MRS and 1H-MRS of tumor extracts showed a significant decrease in phosphocholine (P < or = 0.05). Inhibition of choline kinase by MN58b resulted in altered phospholipid metabolism both in cultured tumor cells and in vivo. Phosphocholine levels were found to correlate with choline kinase activities. The decrease in phosphocholine, total choline, and phosphomonoesters may have potential as noninvasive pharmacodynamic biomarkers for determining tumor response following treatment with choline kinase inhibitors.
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Affiliation(s)
- Nada M S Al-Saffar
- Cancer Research UK Clinical Magnetic Resonance Research Group, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, Sutton, Surrey, United Kingdom
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87
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Ramírez de Molina A, Gallego-Ortega D, Sarmentero J, Bañez-Coronel M, Martín-Cantalejo Y, Lacal JC. Choline Kinase Is a Novel Oncogene that Potentiates RhoA-Induced Carcinogenesis. Cancer Res 2005; 65:5647-53. [PMID: 15994937 DOI: 10.1158/0008-5472.can-04-4416] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Choline kinase is overexpressed in human breast, lung, colorectal, and prostate tumors, a finding that suggests the involvement of this enzyme in carcinogenesis. Here we show that overexpression of choline kinase induce oncogenic transformation of human embryo kidney fibroblasts and canine epithelial Madin-Darby canine kidney cells. Choline kinase lays downstream of RhoA signaling and is activated through ROCK kinase, one of the best-characterized RhoA effectors. In keeping with this, coexpression of RhoA and choline kinase potentiates both anchorage independent growth and tumorigenesis. Finally, choline kinase-mediated transformation is sensitive to MN58b, a well-characterized specific choline kinase inhibitor. These results provide the definitive evidence that choline kinase has oncogenic properties and that choline kinase inhibition constitutes a novel valid antitumor strategy.
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Affiliation(s)
- Ana Ramírez de Molina
- Unidad de Oncología Translacional, Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Cientificas-UAM, Spain
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88
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Choi MG, Kurnov V, Kersting MC, Sreenivas A, Carman GM. Phosphorylation of the yeast choline kinase by protein kinase C. Identification of Ser25 and Ser30 as major sites of phosphorylation. J Biol Chem 2005; 280:26105-12. [PMID: 15919656 PMCID: PMC1383591 DOI: 10.1074/jbc.m503551200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Saccharomyces cerevisiae CKI1-encoded choline kinase catalyzes the committed step in phosphatidylcholine synthesis via the Kennedy pathway. The enzyme is phosphorylated on multiple serine residues, and some of this phosphorylation is mediated by protein kinase A. In this work we examined the hypothesis that choline kinase is also phosphorylated by protein kinase C. Using choline kinase as a substrate, protein kinase C activity was dose- and time-dependent and dependent on the concentrations of choline kinase (K(m) = 27 microg/ml) and ATP (K(m) = 15 microM). This phosphorylation, which occurred on a serine residue, was accompanied by a 1.6-fold stimulation of choline kinase activity. The synthetic peptide SRSSSQRRHS (V5max/K(m) = 17.5 mm(-1) micromol min(-1) mg(-1)) that contains the protein kinase C motif for Ser25 was a substrate for protein kinase C. A Ser25 to Ala (S25A) mutation in choline kinase resulted in a 60% decrease in protein kinase C phosphorylation of the enzyme. Phosphopeptide mapping analysis of the S25A mutant enzyme confirmed that Ser25 was a protein kinase C target site. In vivo the S25A mutation correlated with a decrease (55%) in phosphatidylcholine synthesis via the Kennedy pathway, whereas an S25D phosphorylation site mimic correlated with an increase (44%) in phosphatidylcholine synthesis. Although the S25A (protein kinase C site) mutation did not affect the phosphorylation of choline kinase by protein kinase A, the S30A (protein kinase A site) mutation caused a 46% reduction in enzyme phosphorylation by protein kinase C. A choline kinase synthetic peptide (SQRRHSLTRQ) containing Ser30 was a substrate (V(max)/K(m) = 3.0 mm(-1) micromol min(-1) mg(-1)) for protein kinase C. Comparison of phosphopeptide maps of the wild type and S30A mutant choline kinase enzymes phosphorylated by protein kinase C confirmed that Ser30 was also a target site for protein kinase C.
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Affiliation(s)
| | | | | | | | - George M. Carman
- #To whom correspondence and reprint requests should be addressed. Dept. of Food Science, Rutgers University, 65 Dudley Rd., New Brunswick, NJ 08901. Tel: 732-932-9611 (ext. 217); E-mail:
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89
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Sánchez-Martín R, Campos JM, Conejo-García A, Cruz-López O, Báñez-Coronel M, Rodríguez-González A, Gallo MA, Lacal JC, Espinosa A. Symmetrical Bis-Quinolinium Compounds: New Human Choline Kinase Inhibitors with Antiproliferative Activity against the HT-29 Cell Line. J Med Chem 2005; 48:3354-63. [PMID: 15857141 DOI: 10.1021/jm049061o] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Studies have been aimed at the establishment of structure-activity relationships that define choline kinase inhibitory and antiproliferative activities of 40 bisquinolinium compounds. These derivatives have electron-releasing groups at position 4 of the quinolinium ring. It is found that the enzymatic inhibition is closely related to the size of the linker, the 3,3'-biphenyl moiety being the most suitable. On the other hand, the antiproliferative activity against the HT-29 cancer cell line is less influenced by the linker type and by substituent R(4). The corresponding QSAR equation was obtained for the whole set of compounds for the antiproliferative activity, the electronic parameter sigma(R) of R(4), the molar refractivity of R(8), and the lipophilic parameters clog P and pi(linker). The most potent antiproliferative agent so far described is 40 for which an IC(50) = 0.45 microM was predicted by the QSAR equation, while its experimental value is IC(50) = 0.20 microM.
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Affiliation(s)
- Rosario Sánchez-Martín
- Departamento de Química Farmacéutica y Orgánica, Facultad de Farmacia, Universidad de Granada, c/ Campus de Cartuja s/n, 18071 Granada, Spain
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90
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Conejo-García A, Entrena A, Campos JM, Sánchez-Martín RM, Gallo MA, Espinosa A. Towards a model for the inhibition of choline kinase by a new type of inhibitor. Eur J Med Chem 2005; 40:315-9. [PMID: 15725501 DOI: 10.1016/j.ejmech.2004.09.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2004] [Revised: 09/21/2004] [Accepted: 09/22/2004] [Indexed: 11/28/2022]
Abstract
Bispyridinium cyclophanes are novel templates for human choline kinase inhibitors. Molecular modelling of these compounds suggests three anchorage places at the binding site of the enzyme: (i) two anionic centres of the enzyme active site separated from each other at a distance of approximately 6.2 A that bind the two positively charged nitrogen atoms; (ii) a wide hydrophobic pocket that is fulfilled by the upper linker, the benzene ring that links the two amino groups; and (iii) a smaller hydrophobic pocket that can accommodate the lower benzene ring that links both benzylic carbons. This study may be useful for the development of more potent inhibitors of the enzyme.
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Affiliation(s)
- Ana Conejo-García
- Departamento de Química Farmacéutica y Orgánica, Facultad de Farmacia, Universidad de Granada, Granada 18071, Spain
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91
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Conejo-García A, Báñez-Coronel M, Sánchez-Martín RM, Rodríguez-González A, Ramos A, Ramírez de Molina A, Espinosa A, Gallo MA, Campos JM, Lacal JC. Influence of the linker in bispyridium compounds on the inhibition of human choline kinase. J Med Chem 2004; 47:5433-40. [PMID: 15481981 DOI: 10.1021/jm0496537] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Studies have been aimed to establish the structure-activity relationship that define choline kinase (ChoK) inhibitory potency and antiproliferative activity of a set of 25 bispyridinium compounds with electron-releasing groups at position 4. Here we report that, according to their inhibitory activities against human ChoK, the enzymatic inhibitory potency is closely related to the size of the linker, the 3,3'-biphenyl moiety being the most suitable. The N-methylanilino and its derivatives, 4-chloro-N-methylanilino and 3,5-dichloro-N-methylanilino, render higher ChoK inhibitory and antiproliferative activities against the HT-29 human colon cancer cell line.
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Affiliation(s)
- Ana Conejo-García
- Departamento de Quimica Farmaceutica y Organica, Facultad de Farmacia, Universidad de Grenada, Campus de Cartuja s/n, 18071 Granada, Spain
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92
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Yoshimoto M, Waki A, Obata A, Furukawa T, Yonekura Y, Fujibayashi Y. Radiolabeled choline as a proliferation marker: Comparison with radiolabeled acetate. Nucl Med Biol 2004; 31:859-65. [PMID: 15464387 DOI: 10.1016/j.nucmedbio.2004.05.002] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2004] [Revised: 04/20/2004] [Accepted: 05/15/2004] [Indexed: 11/24/2022]
Abstract
[11C]Choline is a potential tracer to detect tumors, especially brain and prostate cancers. The metabolism of [11C]choline defines the accumulation pattern of [11C]choline in tumors depicted by positron emission tomography. Choline is a precursor of phosphatidylcholine that is a major constituent of membrane lipids. Membrane lipid synthesis as well as DNA synthesis is activated during cell proliferation. We investigated the relation between [14C]choline metabolism and proliferative activity using 10 tumor cell lines and fibroblasts. [14C]Choline uptake was higher in tumor cells than in fibroblasts and was correlated with the proliferative activity, though the sensitivity of [14C]choline uptake to proliferative activity was less than that of [1-14C]acetate. [14C]Phosphocholine produced from [14C]choline by phosphorylation mainly contributed to this accumulation. [11C]Choline can be used for the evaluation of tumor proliferation through estimating choline kinase activity.
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Affiliation(s)
- Mitsuyoshi Yoshimoto
- Biomedical Imaging Research Center, University of Fukui, 23-3, Shimoaizuki, Matsuoka, Yoshida, Fukui, 910-1193, Japan
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93
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Rodríguez-González A, Ramirez de Molina A, Fernández F, Lacal JC. Choline kinase inhibition induces the increase in ceramides resulting in a highly specific and selective cytotoxic antitumoral strategy as a potential mechanism of action. Oncogene 2004; 23:8247-59. [PMID: 15378008 DOI: 10.1038/sj.onc.1208045] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Choline kinase (ChoK, E.C. 2.7.1.32) is involved in the synthesis of phosphatidylcholine (PC), and has been found to be increased in human tumors and tumor-derived cell lines. Furthermore, ChoK inhibitors have been reported to show a potent and selective antitumoral activity both in vitro and in vivo. Here, we provide the basis for a rational understanding of the antitumoral activity of ChoK inhibitors. In normal cells, blockage of de novo phosphorylcholine (PCho) synthesis by inhibition of ChoK promotes the dephosphorylation of pRb, resulting in a reversible cell cycle arrest at G0/G1 phase. In contrast, ChoK inhibition in tumor cells renders cells unable to arrest in G0/G1 as manifested by a lack of pRb dephosphorylation. Furthermore, tumor cells specifically suffer a drastic wobble in the metabolism of main membrane lipids PC and sphingomyelin (SM). This lipid disruption results in the enlargement of the intracellular levels of ceramides. As a consequence, normal cells remain unaffected, but tumor cells are promoted to apoptosis. Thus, we provide in this study the rationale for the potential clinical use of ChoK inhibitors.
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Affiliation(s)
- Agustín Rodríguez-González
- Translational Oncology Unit, Department of Molecular and Cellular Biology of Cancer, Instituto de Investigaciones Biomédicas, CSIC, Arturo Duperier 4, 28029 Madrid, Spain
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94
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Ramírez de Molina A, Báñez-Coronel M, Gutiérrez R, Rodríguez-González A, Olmeda D, Megías D, Lacal JC. Choline Kinase Activation Is a Critical Requirement for the Proliferation of Primary Human Mammary Epithelial Cells and Breast Tumor Progression. Cancer Res 2004; 64:6732-9. [PMID: 15374991 DOI: 10.1158/0008-5472.can-04-0489] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Breast cancer is still one of the most important tumors among women in industrialized countries. Improvement in both understanding the molecular events associated with the disease and the development of new additional treatments is still an important goal to be achieved. Choline kinase (ChoK) is increased in human mammary tumors with high incidence, and this activation is associated with clinical variable indicators of greater malignancy. Here, we have investigated the role of ChoK in the development of breast cancer and found that ChoK is both necessary and sufficient for growth factor-induced proliferation in primary human mammary epithelial cells and an absolute requirement for the specific mitogenic response to heregulin in breast tumor-derived cells. These results demonstrate that ChoK plays an essential role in both normal human mammary epithelial cell proliferation and breast tumor progression. Furthermore, inhibition of ChoK shows a strong in vivo antitumor activity against human breast cancer xenografts. Thus, ChoK constitutes a novel bona fide molecular target for the treatment of breast cancer patients.
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Affiliation(s)
- Ana Ramírez de Molina
- Department of Molecular and Cellular Biology of Cancer, Translational Oncology Unit, Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Cicutíficas, Madrid, Spain
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95
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Abstract
Choline kinase (CK) catalyzes the first phosphorylation reaction in the CDP-choline pathway for the biosynthesis of phosphatidylcholine (PC), yielding phosphocholine (P-Cho) from choline and ATP in the presence of Mg(2+). This enzyme exists in mammalian cells as at least three isoforms that are encoded by two separate genes termed ck-alpha and ck-beta. Each isoform is not active in its monomeric form. The active enzyme consists of either their homo- or hetero-dimeric (or oligomeric) forms. In recent years, the roles of CK in cell growth and cell stress/defense mechanisms have been intensely investigated. These functions of CK do not seem to be directly related to the net PC biosynthesis but predict another important role of this enzyme in certain cell physiology. This review summarizes briefly the recent progress of mammalian CK study which will include the gene structure of each isoform and its possible transcriptional regulation, the active configuration of the enzyme, induction of the particular isoform in chemically induced cell stress, and the possible role of this enzyme as well as of its reaction product, P-Cho, in cell growth and other cellular physiology.
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Affiliation(s)
- Chieko Aoyama
- Medical Research Institute, Tokyo Medical and Dental University, 2-3-10 Kanda-surugadai, Chiyodaku, Tokyo 101-0062, Japan
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96
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Rodríguez-González A, Ramírez de Molina A, Fernández F, Ramos MA, del Carmen Núñez M, Campos J, Lacal JC. Inhibition of choline kinase as a specific cytotoxic strategy in oncogene-transformed cells. Oncogene 2004; 22:8803-12. [PMID: 14654777 DOI: 10.1038/sj.onc.1207062] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Cancer treatment is in the need of selective drugs that can interfere specifically with signalling pathways affected during the carcinogenic process. Identification of new potential molecular targets is the key event in the design of new anticancer strategies. Once identified, attempts for the generation of specific molecules to regulate their function can be achieved. The relevance of deregulation of choline kinase (ChoK, E.C. 2.7.1.32) in oncogene-driven cell transformation has been previously demonstrated. Here we provide strong evidence that MN58b, a selective inhibitor of ChoK, is rather specific to this enzyme, with no effect on a variety of oncogene-activated signalling pathways involved in the regulation of cell proliferation. MN58b does not affect MAPKs, PI3K, and other enzymes involved in the regulation of phospholipid metabolism such as phospholipases C, D, and A2, CTP:phosphocholine cytidylyltransferase, or diacylglycerol choline-phosphotransferase. Consistent with this specificity, ectopic expression of ChoK resulted in resistance to its inhibitor. Finally, nontransformed cells were able to resume cell proliferation after removal of the drug, while transformed cells were irreversibly affected. These results indicate that inhibition of ChoK is a rather specific strategy for the cytotoxic treatment of transformed cells.
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Affiliation(s)
- Agustín Rodríguez-González
- Department of Molecular and Cellular Biology of Cancer, Instituto de Investigaciones Biomédicas (CSIC), Arturo Duperier 4, Madrid 28029, Spain
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97
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Sutinen E, Nurmi M, Roivainen A, Varpula M, Tolvanen T, Lehikoinen P, Minn H. Kinetics of [(11)C]choline uptake in prostate cancer: a PET study. Eur J Nucl Med Mol Imaging 2003; 31:317-24. [PMID: 14628097 DOI: 10.1007/s00259-003-1377-9] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2003] [Accepted: 10/06/2003] [Indexed: 10/26/2022]
Abstract
Carbon-11 choline has recently been introduced as a potential tracer for tumour imaging with positron emission tomography (PET). We evaluated the kinetics of the uptake of [(11)C]choline in prostate cancer and benign prostatic hyperplasia. We also evaluated the association between the uptake of [(11)C]choline and the histological grade of malignancy, Gleason score, volume of the prostate and prostate-specific antigen (PSA). Fourteen patients with histologically confirmed prostate cancer and five patients with benign prostatic hyperplasia were studied with [(11)C]choline PET. A mean dose of 430+/-31 MBq of [(11)C]choline was injected intravenously and a dynamic emission acquisition of prostate was performed for 30 min. The uptake of [(11)C]choline was measured as a standardised uptake value (SUV) and as a kinetic influx constant ( K(i)) obtained from graphical analysis. Both cancerous and hyperplastic prostate were well visualised with [(11)C]choline against low or moderate tracer accumulation in the bladder and rectal wall. The measured radioactivity in urine was invariably low. In the graphical analysis, linear plots were achieved. The mean K(i) of the untreated tumour was 0.205+/-0.089 min(-1) (range 0.128-0.351; n=7) and the mean SUV was 5.6+/-3.2 (range 1.9-15.5; n=15). K(i) values and SUVs correlated closely ( r=0.964, P=0.0005), whereas no correlation could be demonstrated between the tumour uptake of [(11)C]choline and the histological grade, Gleason score, volume of the prostate or PSA. The mean SUV and the mean K(i) of benign hyperplastic prostate were 3.5+/-1.0 (range 2.0-4.5; n=4) and 0.119+/-0.076 min(-1) (range 0.065-0.173; n=2). In conclusion, a high uptake of [(11)C]choline characterises not only carcinomatous but also hyperplastic prostatic tissue. Dynamic imaging of the uptake of [(11)C]choline in the prostate shows a good applicability of the graphical analysis model with an irreversible compartment. A close correlation between the K(i) values and semiquantitative SUVs of tumours supports the use of the simpler SUV in the clinical setting.
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Affiliation(s)
- Eija Sutinen
- Turku PET Centre, Turku University Central Hospital, Turku, Finland.
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98
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Conejo-García A, Campos JM, Sánchez-Martín RM, Gallo MA, Espinosa A. Bispyridinium cyclophanes: novel templates for human choline kinase inhibitors. J Med Chem 2003; 46:3754-7. [PMID: 12904080 DOI: 10.1021/jm030792i] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The synthesis and biological activities of four novel bispyridinium cyclophanes as choline kinase (ChoK) inhibitors are presented. Their synthetic methodology has been optimized according to dilution, temperature, and reaction time and provides pure bispyridinium cyclophanes in high yields very easily. One of these cyclophanes (6, 4,8-diaza-3(1,4),9(4,1)-dipyridina-1(1,4),6(1,3)-dibenzenacyclodecaphan-3(1),9(1)-bis(ilium) dibromide) has an IC(50(ChoK)) of 0.3 microM and is the most potent human ChoK inhibitor described to date.
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Affiliation(s)
- Ana Conejo-García
- Departamento de Química Farmacéutica y Orgánica, Facultad de Farmacia, c/Campus de Cartuja s/n, 18071 Granada, Spain
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99
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Peisach D, Gee P, Kent C, Xu Z. The crystal structure of choline kinase reveals a eukaryotic protein kinase fold. Structure 2003; 11:703-13. [PMID: 12791258 DOI: 10.1016/s0969-2126(03)00094-7] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Choline kinase catalyzes the ATP-dependent phosphorylation of choline, the first committed step in the CDP-choline pathway for the biosynthesis of phosphatidylcholine. The 2.0 A crystal structure of a choline kinase from C. elegans (CKA-2) reveals that the enzyme is a homodimeric protein with each monomer organized into a two-domain fold. The structure is remarkably similar to those of protein kinases and aminoglycoside phosphotransferases, despite no significant similarity in amino acid sequence. Comparisons to the structures of other kinases suggest that ATP binds to CKA-2 in a pocket formed by highly conserved and catalytically important residues. In addition, a choline binding site is proposed to be near the ATP binding pocket and formed by several structurally flexible loops.
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Affiliation(s)
- Daniel Peisach
- Department of Biological Chemistry, University of Michigan Medical School, 1301 East Catherine Road, Ann Arbor, MI 48109, USA
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100
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Campos J, Núñez C, Díaz JJ, Sánchez RM, Gallo MA, Espinosa A. Anticancer bisquaternary heterocyclic compounds: a ras-ional design. FARMACO (SOCIETA CHIMICA ITALIANA : 1989) 2003; 58:221-9. [PMID: 12620418 DOI: 10.1016/s0014-827x(03)00020-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A new family of symmetrical bisquaternary compounds with semirigid linkers have shown to be highly specific for Choline Kinase (ChoK) inhibition and to exert antitumoural activity in cell lines and in mice. A three-parameter regression equation has been derived which satisfactorily describes the ex vivo inhibitory potency of ChoK of the title compounds. The electronic effect of the group at position 4 of the cationic head plays a critical role although the hydrophobic contribution, especially that of the linker, favors the ChoK inhibitory activity. The antiproliferative activity (in vitro assay) is correlated with the ChoK inhibition (ex vivo assay) through the electronic effect and a squared term of the overall lipophilicity of the molecules. We also provide in vivo evidence that ChoK is a novel target for the design of antitumoural drugs. All these results suggest that ChoK plays a crucial role in the onset of carcinogenesis.
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Affiliation(s)
- Joaquín Campos
- Departamento de Química Farmacéutica y Orgánica, Facultad de Farmacia, Universidad de Granada, c/ Campus de Cartuja, s/n 18071 Granada, Spain.
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