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Penet MF, Sharma RK, Bharti S, Mori N, Artemov D, Bhujwalla ZM. Cancer insights from magnetic resonance spectroscopy of cells and excised tumors. NMR IN BIOMEDICINE 2023; 36:e4724. [PMID: 35262263 PMCID: PMC9458776 DOI: 10.1002/nbm.4724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 03/03/2022] [Accepted: 03/04/2022] [Indexed: 06/14/2023]
Abstract
Multinuclear ex vivo magnetic resonance spectroscopy (MRS) of cancer cells, xenografts, human cancer tissue, and biofluids is a rapidly expanding field that is providing unique insights into cancer. Starting from the 1970s, the field has continued to evolve as a stand-alone technology or as a complement to in vivo MRS to characterize the metabolome of cancer cells, cancer-associated stromal cells, immune cells, tumors, biofluids and, more recently, changes in the metabolome of organs induced by cancers. Here, we review some of the insights into cancer obtained with ex vivo MRS and provide a perspective of future directions. Ex vivo MRS of cells and tumors provides opportunities to understand the role of metabolism in cancer immune surveillance and immunotherapy. With advances in computational capabilities, the integration of artificial intelligence to identify differences in multinuclear spectral patterns, especially in easily accessible biofluids, is providing exciting advances in detection and monitoring response to treatment. Metabolotheranostics to target cancers and to normalize metabolic changes in organs induced by cancers to prevent cancer-induced morbidity are other areas of future development.
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Affiliation(s)
- Marie-France Penet
- Division of Cancer Imaging Research, The Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, Maryland, USA
- Sidney Kimmel Comprehensive Cancer Center, Baltimore, Maryland, USA
| | - Raj Kumar Sharma
- Division of Cancer Imaging Research, The Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, Maryland, USA
| | - Santosh Bharti
- Division of Cancer Imaging Research, The Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, Maryland, USA
| | - Noriko Mori
- Division of Cancer Imaging Research, The Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, Maryland, USA
| | - Dmitri Artemov
- Division of Cancer Imaging Research, The Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, Maryland, USA
- Sidney Kimmel Comprehensive Cancer Center, Baltimore, Maryland, USA
| | - Zaver M. Bhujwalla
- Division of Cancer Imaging Research, The Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, Maryland, USA
- Sidney Kimmel Comprehensive Cancer Center, Baltimore, Maryland, USA
- Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Roy J, Dibaeinia P, Fan TM, Sinha S, Das A. Global analysis of osteosarcoma lipidomes reveal altered lipid profiles in metastatic versus nonmetastatic cells. J Lipid Res 2018; 60:375-387. [PMID: 30504231 DOI: 10.1194/jlr.m088559] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 11/21/2018] [Indexed: 12/15/2022] Open
Abstract
Osteosarcoma (OS) is the most common form of primary bone cancer in humans. The early detection and subsequent control of metastasis has been challenging in OS. Lipids are important constituents of cells that maintain structural integrity that can be converted into lipid-signaling molecules and are reprogrammed in cancerous states. Here, we investigate the global lipidomic differences in metastatic (143B) and nonmetastatic (HOS) human OS cells as compared with normal fetal osteoblast cells (FOB) using lipidomics. We detect 15 distinct lipid classes in all three cell lines that included over 1,000 lipid species across various classes including phospholipids, sphingolipids and ceramides, glycolipids, and cholesterol. We identify a key class of lipids, diacylglycerols, which are overexpressed in metastatic OS cells as compared with their nonmetastatic or nontumorigenic counterparts. As a proof of concept, we show that blocking diacylglycerol synthesis reduces cellular viability and reduces cell migration in metastatic OS cells. Thus, the differentially regulated lipids identified in this study might aid in biomarker discovery, and the synthesis and metabolism of specific lipids could serve as future targets for therapeutic development.
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Affiliation(s)
- Jahnabi Roy
- Department of Chemistry, University of Illinois Urbana-Champaign, Urbana, IL 61802
| | - Payam Dibaeinia
- Department of Computer Science, University of Illinois Urbana-Champaign, Urbana, IL 61802
| | - Timothy M Fan
- Department of Veterinary Clinical Medicine, University of Illinois Urbana-Champaign, Urbana, IL 61802
| | - Saurabh Sinha
- Department of Computer Science, University of Illinois Urbana-Champaign, Urbana, IL 61802.,Neuroscience Program and Department of Bioengineering, Institute of Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL 61802
| | - Aditi Das
- Department of Comparative Biosciences, University of Illinois Urbana-Champaign, Urbana, IL 61802 .,Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, IL 61802.,Beckman Institute for Advanced Science, Division of Nutritional Sciences, Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, IL 61802
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3
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Mori N, Wildes F, Takagi T, Glunde K, Bhujwalla ZM. The Tumor Microenvironment Modulates Choline and Lipid Metabolism. Front Oncol 2016; 6:262. [PMID: 28066718 PMCID: PMC5177616 DOI: 10.3389/fonc.2016.00262] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 12/09/2016] [Indexed: 12/22/2022] Open
Abstract
An increase of cellular phosphocholine (PC) and total choline (tCho)-containing compounds as well as alterations in lipids have been consistently observed in cancer cells and tissue. These metabolic changes are closely related to malignant transformation, invasion, and metastasis. The study of cancer cells in culture plays an important role in understanding mechanisms leading to altered choline (Cho) and lipid metabolism in cancer, as it provides a carefully controlled environment. However, a solid tumor is a complex system with a unique tumor microenvironment frequently containing hypoxic and acidic regions and areas of nutrient deprivation and necrosis. Cancer cell–stromal cell interactions and the extracellular matrix may also alter Cho and lipid metabolism. Human tumor xenograft models in mice are useful to mimic the growth of human cancers and provide insights into the influence of in vivo conditions on metabolism. Here, we have compared metabolites, obtained with high resolution 1H MRS of extracts from human breast and prostate cancer cells in a 2-dimensional (2D) monolayer culture and from solid tumor xenografts derived from these cells, as well as the protein expression of enzymes that regulate Cho and lipid metabolism. Our data demonstrate significant differences in Cho and lipid metabolism and protein expression patterns between human breast and prostate cancer cells in culture and in tumors derived from these cells. These data highlight the influence of the tumor microenvironment on Cho and lipid metabolism.
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Affiliation(s)
- Noriko Mori
- JHU ICMIC Program, Division of Cancer Imaging Research, The Russell H. Morgan Department of Radiology and Radiological Science , Baltimore, MD , USA
| | - Flonné Wildes
- JHU ICMIC Program, Division of Cancer Imaging Research, The Russell H. Morgan Department of Radiology and Radiological Science , Baltimore, MD , USA
| | - Tomoyo Takagi
- JHU ICMIC Program, Division of Cancer Imaging Research, The Russell H. Morgan Department of Radiology and Radiological Science , Baltimore, MD , USA
| | - Kristine Glunde
- JHU ICMIC Program, Division of Cancer Imaging Research, The Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD, USA; Sidney Kimmel Comprehensive Cancer Center, School of Medicine, The Johns Hopkins University, Baltimore, MD, USA
| | - Zaver M Bhujwalla
- JHU ICMIC Program, Division of Cancer Imaging Research, The Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD, USA; Sidney Kimmel Comprehensive Cancer Center, School of Medicine, The Johns Hopkins University, Baltimore, MD, USA
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Mori N, Gadiya M, Wildes F, Krishnamachary B, Glunde K, Bhujwalla ZM. Characterization of choline kinase in human endothelial cells. NMR IN BIOMEDICINE 2013; 26:1501-1507. [PMID: 23775813 PMCID: PMC3800480 DOI: 10.1002/nbm.2983] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 05/08/2013] [Accepted: 05/10/2013] [Indexed: 06/02/2023]
Abstract
High choline kinase-α (Chk-α) expression is frequently observed in cancer cells, making it a novel target for pharmacological and molecular inhibition. As inhibiting agents are delivered systemically, it is important to determine Chk-α expression levels in endothelial cells that line both normal and tumor vasculature, and the effect of Chk-α downregulation on these cells. Here, we characterized Chk-α expression and the effect of its downregulation in human umbilical vein endothelial cells (HUVECs) relative to MDA-MB-231 human breast cancer cells. We used small interfering RNA (siRNA) to downregulate Chk-α expression. Basal mRNA levels of Chk-α were approximately three-fold lower in HUVECs relative to MDA-MB-231 breast cancer cells. Consistent with the differences in Chk-α protein levels, phosphocholine levels were approximately 10-fold lower in HUVECs relative to MDA-MB-231 cells. Transient transfection with siRNA-Chk resulted in comparable levels of mRNA and protein in MDA-MB-231 breast cancer cells and HUVECs. However, there was a significant reduction in proliferation in MDA-MB-231 cells, but not in HUVECs. No significant difference in CD31 immunostaining was observed in tumor sections obtained from mice injected with control luciferase-short hairpin (sh)RNA or Chk-shRNA lentivirus. These data suggest that systemically delivered agents that downregulate Chk-α in tumors will not affect endothelial cell proliferation during delivery, and further support the development of Chk-α downregulation as a cancer-specific treatment.
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Affiliation(s)
- Noriko Mori
- JHU ICMIC Program, Division of Cancer Imaging Research, The
Russell H. Morgan Department of Radiology and Radiological Science
| | - Mayur Gadiya
- JHU ICMIC Program, Division of Cancer Imaging Research, The
Russell H. Morgan Department of Radiology and Radiological Science
| | - Flonne Wildes
- JHU ICMIC Program, Division of Cancer Imaging Research, The
Russell H. Morgan Department of Radiology and Radiological Science
| | - Balaji Krishnamachary
- JHU ICMIC Program, Division of Cancer Imaging Research, The
Russell H. Morgan Department of Radiology and Radiological Science
| | - Kristine Glunde
- JHU ICMIC Program, Division of Cancer Imaging Research, The
Russell H. Morgan Department of Radiology and Radiological Science
| | - Zaver M. Bhujwalla
- JHU ICMIC Program, Division of Cancer Imaging Research, The
Russell H. Morgan Department of Radiology and Radiological Science
- Sidney Kimmel Comprehensive Cancer Center, The Johns
Hopkins University, School of Medicine, Baltimore, Maryland 21205
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Penet MF, Chen Z, Bhujwalla ZM. MRI of metastasis-permissive microenvironments. Future Oncol 2012; 7:1269-84. [PMID: 22044202 DOI: 10.2217/fon.11.114] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
One of the earliest documented observations of the importance of the microenvironment in metastasis was made by Stephen Paget in 1889. More than a century later, the metastatic cascade remains a major cause of mortality from cancer. Cancer meets the criterion of a successful organization that is able to survive by adapting to changing environments. In fact, the tumor microenvironment and stroma are co-opted and shaped by cancer cells to derive a survival advantage. Cohesive strategies integrating advances in molecular biology and chemistry, with noninvasive multimodality imaging, provide new insights into the role of the tumor microenvironment in promoting metastasis from primary tumors as well as insights into environments that attract and permit cancer cells to establish colonies in distant organs. This article provides an overview of molecular and functional imaging characterization of microenvironments that can promote or permit cancer cells to metastasize and the microenvironmental characteristics of distant metastases.
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Affiliation(s)
- Marie-France Penet
- JHU In vivo Cellular & Molecular Imaging Center, The Russell H. Morgan Department of Radiology & Radiological Science, Baltimore, MD, USA.
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6
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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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Podo F, Canevari S, Canese R, Pisanu ME, Ricci A, Iorio E. MR evaluation of response to targeted treatment in cancer cells. NMR IN BIOMEDICINE 2011; 24:648-672. [PMID: 21387442 DOI: 10.1002/nbm.1658] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Revised: 11/22/2010] [Accepted: 11/29/2010] [Indexed: 05/30/2023]
Abstract
The development of molecular technologies, together with progressive sophistication of molecular imaging methods, has allowed the further elucidation of the multiple mutations and dysregulatory effects of pathways leading to oncogenesis. Acting against these pathways by specifically targeted agents represents a major challenge for current research efforts in oncology. As conventional anatomically based pharmacological endpoints may be inadequate to monitor the tumor response to these targeted treatments, the identification and use of more appropriate, noninvasive pharmacodynamic biomarkers appear to be crucial to optimize the design, dosage and schedule of these novel therapeutic approaches. An aberrant choline phospholipid metabolism and enhanced flux of glucose derivatives through glycolysis, which sustain the redirection of mitochondrial ATP to glucose phosphorylation, are two major hallmarks of cancer cells. This review focuses on the changes detected in these pathways by MRS in response to targeted treatments. The progress and limitations of our present understanding of the mechanisms underlying MRS-detected phosphocholine accumulation in cancer cells are discussed in the light of gene and protein expression and the activation of different enzymes involved in phosphatidylcholine biosynthesis and catabolism. Examples of alterations induced in the MRS choline profile of cells exposed to different agents or to tumor environmental factors are presented. Current studies aimed at the identification in cancer cells of MRS-detected pharmacodynamic markers of therapies targeted against specific conditional or constitutive cell receptor stimulation are then reviewed. Finally, the perspectives of present efforts addressed to identify enzymes of the phosphatidylcholine cycle as possible novel targets for anticancer therapy are summarized.
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Affiliation(s)
- Franca Podo
- Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Rome, Italy.
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Amstalden van Hove ER, Blackwell TR, Klinkert I, Eijkel GB, Heeren RMA, Glunde K. Multimodal mass spectrometric imaging of small molecules reveals distinct spatio-molecular signatures in differentially metastatic breast tumor models. Cancer Res 2010; 70:9012-21. [PMID: 21045154 DOI: 10.1158/0008-5472.can-10-0360] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Phosphocholine (PC) and total choline (tCho) are increased in malignant breast tumors. In this study, we combined magnetic resonance spectroscopic imaging (MRSI), mass spectrometry (MS) imaging, and pathologic assessment of corresponding tumor sections to investigate the localization of choline metabolites and cations in viable versus necrotic tumor regions in the nonmetastatic MCF-7 and the highly metastatic MDA-MB-231 breast cancer xenograft models. In vivo three-dimensional MRSI showed that high tCho levels, consisting of free choline (Cho), PC, and glycerophosphocholine (GPC), displayed a heterogeneous spatial distribution in the tumor. MS imaging performed on tumor sections detected the spatial distributions of individual PC, Cho, and GPC, as well as sodium (Na+) and potassium (K+), among many others. PC and Cho intensity were increased in viable compared with necrotic regions of MDA-MB-231 tumors, but relatively homogeneously distributed in MCF-7 tumors. Such behavior may be related to the role of PC and PC-related enzymes, such as choline kinase, choline transporters, and others, in malignant tumor growth. Na+ and K+ colocalized in the necrotic tumor areas of MDA-MB-231 tumors, whereas in MCF-7 tumors, Na+ was detected in necrotic and K+ in viable tumor regions. This may be attributed to differential Na+/K+ pump functions and K+ channel expressions. Principal component analysis of the MS imaging data clearly identified different tumor microenvironmental regions by their distinct molecular signatures. This molecular information allowed us to differentiate between distinct tumor regions and tumor types, which may, in the future, prove clinically useful in the pathologic assessment of breast cancers.
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Vizán P, Sánchez-Tena S, Alcarraz-Vizán G, Soler M, Messeguer R, Pujol MD, Lee WNP, Cascante M. Characterization of the metabolic changes underlying growth factor angiogenic activation: identification of new potential therapeutic targets. Carcinogenesis 2009; 30:946-52. [PMID: 19369582 DOI: 10.1093/carcin/bgp083] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Angiogenesis is a fundamental process to normal and abnormal tissue growth and repair, which consists of recruiting endothelial cells toward an angiogenic stimulus. The cells subsequently proliferate and differentiate to form endothelial tubes and capillary-like structures. Little is known about the metabolic adaptation of endothelial cells through such a transformation. We studied the metabolic changes of endothelial cell activation by growth factors using human umbilical vein endothelial cells (HUVECs), [1,2-(13)C(2)]-glucose and mass isotopomer distribution analysis. The metabolism of [1,2-(13)C(2)]-glucose by HUVEC allows us to trace many of the main glucose metabolic pathways, including glycogen synthesis, the pentose cycle and the glycolytic pathways. So we established that these pathways were crucial to endothelial cell proliferation under vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF) stimulation. A specific VEGF receptor-2 inhibitor demonstrated the importance of glycogen metabolism and pentose cycle pathway. Furthermore, we showed that glycogen was depleted in a low glucose medium, but conserved under hypoxic conditions. Finally, we demonstrated that direct inhibition of key enzymes to glycogen metabolism and pentose phosphate pathways reduced HUVEC viability and migration. In this regard, inhibitors of these pathways have been shown to be effective antitumoral agents. To sum up, our data suggest that the inhibition of metabolic pathways offers a novel and powerful therapeutic approach, which simultaneously inhibits tumor cell proliferation and tumor-induced angiogenesis.
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Affiliation(s)
- Pedro Vizán
- Department of Biochemistry and Molecular Biology, University of Barcelona, Spain
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Sterin M, Ringel I, Lecht S, Lelkes PI, Lazarovici P. 31P magnetic resonance spectroscopy of endothelial cells grown in three-dimensional matrigel construct as an enabling platform technology: I. The effect of glial cells and valproic acid on phosphometabolite levels. ACTA ACUST UNITED AC 2009; 15:288-98. [PMID: 19065320 DOI: 10.1080/10623320802487841] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Very few studies describe endothelial cell (EC) properties under three-dimensional (3D) conditions using (31)P magnetic resonance spectroscopy (MRS). The authors developed a model in which living ECs growing in Matrigel threads (3D conditions) for 5 days are monitored by (31)P MRS, providing the fingerprint of the major EC phosphometabolites. Organic extracts of membranal phospholipids were also analyzed by (31)P MRS. For comparison and as a model for two-dimensional (2D) tissue culture conditions, (31)P MRS spectra of aqueous extracts of EC phosphometabolites grown under 2D conditions were also evaluated. The phosphometabolites fingerprint of the cells cultured under 3D was significantly different from that of ECs maintained under 2D. Moreover, the pattern of phosphometabolites was affected by coculture with C6-glioma cells and upon treatment with valproic acid, which is under clinical investigation as an antioangiogenic anticancer drug. The major effects were modulation of (i) energy metabolism intermediates such as phosphocreatine, (ii) precursors of phospholipids such as phosphomonoesters, and (iii) degradation products of phospholipids such as glycerophosphocholine. This endothelial model will be usefull as an enabling platform technology for tissue engineering.
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Affiliation(s)
- M Sterin
- Department of Pharmacology and Experimental Therapeutics, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
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Hypoxia and the presence of human vascular endothelial cells affect prostate cancer cell invasion and metabolism. Neoplasia 2008; 9:1138-51. [PMID: 18084621 DOI: 10.1593/neo.07568] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2007] [Revised: 10/12/2007] [Accepted: 10/15/2007] [Indexed: 11/18/2022] Open
Abstract
Tumor progression and metastasis are influenced by hypoxia, as well as by interactions between cancer cells and components of the stroma, such as endothelial cells. Here, we have used a magnetic resonance (MR)-compatible invasion assay to further understand the effects of hypoxia on human prostate cancer cell invasion and metabolism in the presence and absence of human umbilical vein endothelial cells (HUVECs). Additionally, we compared endogenous activities of selected proteases related to invasion in PC-3 cells and HUVECs, profiled gene expression of PC-3 cells by microarray, and evaluated cell proliferation of PC-3 cells and HUVECs by flow cytometry, under hypoxic and oxygenated conditions. The invasion of less-invasive DU-145 cells was not affected by either hypoxia or the presence of HUVECs. However, hypoxia significantly decreased the invasion of PC-3 cells. This hypoxia-induced decrease was attenuated by the presence of HUVECs, whereas under oxygenated conditions, HUVECs did not alter the invasion of PC-3 cells. Cell metabolism changed distinctly with hypoxia and invasion. The endogenous activity of selected extracellular proteases, although altered by hypoxia, did not fully explain the hypoxia-induced changes in invasion. Gene expression profiling indicated that hypoxia affects multiple cellular functions and pathways.
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Glunde K, Shah T, Winnard PT, Raman V, Takagi T, Vesuna F, Artemov D, Bhujwalla ZM. Hypoxia regulates choline kinase expression through hypoxia-inducible factor-1 alpha signaling in a human prostate cancer model. Cancer Res 2008; 68:172-80. [PMID: 18172309 PMCID: PMC5606139 DOI: 10.1158/0008-5472.can-07-2678] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The intensity of the total choline (tCho) signal in spectroscopic images of tumors is spatially heterogeneous. The likewise heterogeneous physiologic tumor microenvironment may contribute to this heterogeneity. We therefore investigated the relationship between hypoxia, choline metabolites, and choline kinase (Chk) in a human prostate cancer model. Human PC-3 prostate cancer cells were engineered to express enhanced green fluorescent protein (EGFP) under hypoxic conditions. These PC-3-5HRE-EGFP cells were characterized in culture and as tumors transplanted in mice using (1)H magnetic resonance spectroscopy (MRS) and MRS imaging (MRSI) combined with EGFP fluorescence microscopy and imaging. Hypoxic EGFP-fluorescing tumor regions colocalized with regions of high tCho in combined MRSI and optical imaging studies. Cellular phosphocholine (PC) and tCho concentrations as well as Chk expression levels significantly increased following exposure of PC-3 cells to hypoxia. A putative promoter region located 5' of the translation start site of the human chk-alpha gene was cloned and luciferase (Luc)-based reporter vector constructs were generated. Luc reporter assays provided evidence that some of the putative hypoxia response elements (HRE) within this putative chk-alpha promoter region functioned in vitro. Chromatin immunoprecipitation assays using an antibody against hypoxia-inducible factor (HIF)-1 alpha showed that HIF-1 can directly bind this region of the endogenous chk-alpha promoter in hypoxic PC-3-5HRE-EGFP cells. These data suggest that HIF-1 activation of HREs within the putative chk-alpha promoter region can increase Chk-alpha expression within hypoxic environments, consequently increasing cellular PC and tCho levels within these environments.
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Affiliation(s)
- Kristine Glunde
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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Glunde K, Jie C, Bhujwalla ZM. Molecular Causes of the Aberrant Choline Phospholipid Metabolism in Breast Cancer. Cancer Res 2004; 64:4270-6. [PMID: 15205341 DOI: 10.1158/0008-5472.can-03-3829] [Citation(s) in RCA: 291] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Proton magnetic resonance spectroscopy ((1)H MRS) consistently detects significant differences in choline phospholipid metabolites of malignant versus benign breast lesions. It is critically important to understand the molecular causes underlying these metabolic differences, because this may identify novel targets for attack in cancer cells. In this study, differences in choline membrane metabolism were characterized in breast cancer cells and normal human mammary epithelial cells (HMECs) labeled with [1,2-(13)C]choline, using (1)H and (13)C magnetic resonance spectroscopy. Metabolic fluxes between membrane and water-soluble pool of choline-containing metabolites were assessed by exposing cells to [1,2-(13)C]choline for long and short periods of time to distinguish between catabolic and anabolic pathways in choline metabolism. Gene expression analysis using microarrays was performed to understand the molecular mechanisms underlying these changes. Breast cancer cells exhibited increased phosphocholine (PC; P < 0.001), total choline-containing metabolites (P < 0.01), and significantly decreased glycerophosphocholine (P < 0.05) compared with normal HMECs. Decreased (13)C-enrichment was detected in choline (P < 0.001) and phosphocholine (P < 0.05, P < 0.001) of breast cancer cells compared with HMECs, indicating a higher metabolic flux from membrane phosphatidylcholine to choline and phosphocholine in breast cancer cells. Choline kinase and phospholipase C were significantly overexpressed, and lysophospholipase 1, phospholipase A2, and phospholipase D were significantly underexpressed, in breast cancer cells compared with HMECs. The magnetic resonance spectroscopy data indicated that elevated phosphocholine in breast cancer cells was primarily attributable to increased choline kinase activity and increased catabolism mediated by increased phospholipase C activity. These observations were consistent with the overexpression of choline kinase and phospholipase C detected in the microarray analyses.
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Affiliation(s)
- Kristine Glunde
- Magnetic Resonance Oncology Section, Division of Magnetic Resonance Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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Ackerstaff E, Glunde K, Bhujwalla ZM. Choline phospholipid metabolism: A target in cancer cells? J Cell Biochem 2003; 90:525-33. [PMID: 14523987 DOI: 10.1002/jcb.10659] [Citation(s) in RCA: 264] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The experience of treating cancer over the past several decades overwhelmingly demonstrates that the disease continues to evade the vast array of drugs and treatment modalities available in the twenty-first century. This is not surprising in view of the complexity of this disease, and the multiplicities of pathways available to the cancer cell to enable its survival. Although the progression of cancer arrives at a common end point of cachexia, organ failure, and death, common pathways are rare in cancer. Identifying and targeting common pathways that would act across these levels of multiplicity is essential for the successful treatment of this disease. Over the past decade, one common characteristic consistently revealed by magnetic resonance spectroscopic studies is the elevation of phosphocholine and total choline-containing compounds in cancer cells and solid tumors. This elevation has been observed in almost every single cancer type studied with NMR spectroscopy and can be used as an endogenous biomarker of cancer. In this article, we have summarized some of the observations on the choline phospholipid metabolism of cancer cells and tumors, and make a case for targeting the aberrant choline phospholipid metabolism of cancer cells.
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Affiliation(s)
- Ellen Ackerstaff
- Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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