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Yao N, Li W, Xu G, Duan N, Yu G, Qu J. Choline metabolism and its implications in cancer. Front Oncol 2023; 13:1234887. [PMID: 38023163 PMCID: PMC10646347 DOI: 10.3389/fonc.2023.1234887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 10/17/2023] [Indexed: 12/01/2023] Open
Abstract
Choline, a quintessential quaternary ammonium compound, plays a cardinal role in several pivotal biological mechanisms, chiefly in safeguarding cell membrane integrity, orchestrating methylation reactions, and synthesizing vital neurotransmitters. This systematic review meticulously dissects the complex interplay between choline metabolism and its profound implications in oncology. The exposition is stratified into three salient dimensions: Initially, we delve into the intricacies of choline metabolism, accentuating its indispensability in cellular physiology, the enzymatic labyrinth governing its flux, and the pivotal cellular import mechanisms. Subsequently, we elucidate the contemporary comprehension of choline metabolism in the cancer paradigm, traversing its influence from inception to the intricate metamorphosis during oncogenic progression, further compounded by dysregulated enzyme activities and aberrant signaling cascades. Conclusively, we illuminate the burgeoning potential of choline-centric metabolic imaging modalities, notably magnetic resonance spectroscopy (MRS) and positron emission tomography (PET), as avant-garde tools for cancer diagnostics and therapeutic trajectory monitoring. Synoptically, the nuanced perturbations in choline metabolism in neoplastic entities unfurl critical insights, potentially heralding paradigm shifts in diagnostic and therapeutic oncological stratagems. A deeper foray into this realm is anticipated to fortify our molecular understanding and refine intervention modalities in cancer theranostics.
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Affiliation(s)
- Nan Yao
- Department of General Surgery, Aerospace Center Hospital, Beijing, China
| | - Wenqiang Li
- Department of General Surgery, Aerospace Center Hospital, Beijing, China
| | - Guoshuai Xu
- Department of General Surgery, Aerospace Center Hospital, Beijing, China
| | - Ning Duan
- Department of General Surgery, Aerospace Center Hospital, Beijing, China
| | - Guoyong Yu
- Department of Nephrology, Beijing University of Chinese Medicine Affiliated Dongzhimen Hospital, Beijing, China
| | - Jun Qu
- Department of General Surgery, Aerospace Center Hospital, Beijing, China
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2
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High-throughput optical assays for sensing serine hydrolases in living systems and their applications. Trends Analyt Chem 2022. [DOI: 10.1016/j.trac.2022.116620] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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3
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Rubtsova NI, Hart MC, Arroyo AD, Osharovich SA, Liebov BK, Miller J, Yuan M, Cochran JM, Chong S, Yodh AG, Busch TM, Delikatny EJ, Anikeeva N, Popov AV. NIR Fluorescent Imaging and Photodynamic Therapy with a Novel Theranostic Phospholipid Probe for Triple-Negative Breast Cancer Cells. Bioconjug Chem 2021; 32:1852-1863. [PMID: 34139845 DOI: 10.1021/acs.bioconjchem.1c00295] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
New exogenous probes are needed for both imaging diagnostics and therapeutics. Here, we introduce a novel nanocomposite near-infrared (NIR) fluorescent imaging probe and test its potency as a photosensitizing agent for photodynamic therapy (PDT) against triple-negative breast cancer cells. The active component in the nanocomposite is a small molecule, pyropheophorbide a-phosphatidylethanolamine-QSY21 (Pyro-PtdEtn-QSY), which is imbedded into lipid nanoparticles for transport in the body. The probe targets abnormal choline metabolism in cancer cells; specifically, the overexpression of phosphatidylcholine-specific phospholipase C (PC-PLC) in breast, prostate, and ovarian cancers. Pyro-PtdEtn-QSY consists of a NIR fluorophore and a quencher, attached to a PtdEtn moiety. It is selectively activated by PC-PLC resulting in enhanced fluorescence in cancer cells compared to normal cells. In our in vitro investigation, four breast cancer cell lines showed higher probe activation levels than noncancerous control cells, immortalized human mammary gland cells, and normal human T cells. Moreover, the ability of this nanocomposite to function as a sensitizer in PDT experiments on MDA-MB-231 cells suggests that the probe is promising as a theranostic agent.
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Affiliation(s)
- Natalia I Rubtsova
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 3620 Hamilton Walk, Philadelphia, Pennsylvania 19104, United States
| | - Michael C Hart
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 3620 Hamilton Walk, Philadelphia, Pennsylvania 19104, United States
| | - Alejandro D Arroyo
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 3620 Hamilton Walk, Philadelphia, Pennsylvania 19104, United States
| | - Sofya A Osharovich
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 3620 Hamilton Walk, Philadelphia, Pennsylvania 19104, United States
| | - Benjamin K Liebov
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 3620 Hamilton Walk, Philadelphia, Pennsylvania 19104, United States
| | - Joann Miller
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Boulevard, Bldg 421, Philadelphia, Pennsylvania 19104, United States
| | - Min Yuan
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Boulevard, Bldg 421, Philadelphia, Pennsylvania 19104, United States
| | - Jeffrey M Cochran
- Department of Physics and Astronomy, University of Pennsylvania, 3231 Walnut Street, Philadelphia, Pennsylvania 19104, United States
| | - Sanghoon Chong
- Department of Physics and Astronomy, University of Pennsylvania, 3231 Walnut Street, Philadelphia, Pennsylvania 19104, United States
| | - Arjun G Yodh
- Department of Physics and Astronomy, University of Pennsylvania, 3231 Walnut Street, Philadelphia, Pennsylvania 19104, United States
| | - Theresa M Busch
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Boulevard, Bldg 421, Philadelphia, Pennsylvania 19104, United States
| | - E James Delikatny
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 3620 Hamilton Walk, Philadelphia, Pennsylvania 19104, United States
| | - Nadia Anikeeva
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, United States
| | - Anatoliy V Popov
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, 3620 Hamilton Walk, Philadelphia, Pennsylvania 19104, United States
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4
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Alekseeva AS, Boldyrev IA. Phospholipase A2. Methods for Activity Monitoring. BIOCHEMISTRY (MOSCOW), SUPPLEMENT SERIES A: MEMBRANE AND CELL BIOLOGY 2020. [DOI: 10.1134/s1990747820040030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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5
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Varandas PAMM, Cobb AJA, Segundo MA, Silva EMP. Emergent Glycerophospholipid Fluorescent Probes: Synthesis and Applications. Bioconjug Chem 2019; 31:417-435. [DOI: 10.1021/acs.bioconjchem.9b00660] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Pedro A. M. M. Varandas
- LAQV, REQUIMTE, Department of Chemistry Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Alexander J. A. Cobb
- Department of Chemistry, King’s College London, 7 Trinity Street, London SE1 1DB, United Kingdom
| | - Marcela A. Segundo
- LAQV, REQUIMTE, Department of Chemistry Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Eduarda M. P. Silva
- LAQV, REQUIMTE, Department of Chemistry Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
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6
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Arlauckas SP, Browning EA, Poptani H, Delikatny EJ. Imaging of cancer lipid metabolism in response to therapy. NMR IN BIOMEDICINE 2019; 32:e4070. [PMID: 31107583 DOI: 10.1002/nbm.4070] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Revised: 12/21/2018] [Accepted: 12/21/2018] [Indexed: 06/09/2023]
Abstract
Lipids represent a diverse array of molecules essential to the cell's structure, defense, energy, and communication. Lipid metabolism can often become dysregulated during tumor development. During cancer therapy, targeted inhibition of cell proliferation can likewise cause widespread and drastic changes in lipid composition. Molecular imaging techniques have been developed to monitor altered lipid profiles as a biomarker for cancer diagnosis and treatment response. For decades, MRS has been the dominant non-invasive technique for studying lipid metabolite levels. Recent insights into the oncogenic transformations driving changes in lipid metabolism have revealed new mechanisms and signaling molecules that can be exploited using optical imaging, mass spectrometry imaging, and positron emission tomography. These novel imaging modalities have provided researchers with a diverse toolbox to examine changes in lipids in response to a wide array of anticancer strategies including chemotherapy, radiation therapy, signal transduction inhibitors, gene therapy, immunotherapy, or a combination of these strategies. The understanding of lipid metabolism in response to cancer therapy continues to evolve as each therapeutic method emerges, and this review seeks to summarize the current field and areas of unmet needs.
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Affiliation(s)
- Sean Philip Arlauckas
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Center for Systems Biology, Mass General Hospital, Boston, MA, USA
| | - Elizabeth Anne Browning
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Harish Poptani
- Department of Cellular and Molecular Physiology, Institute of Regenerative Medicine, University of Liverpool, Liverpool, UK
| | - Edward James Delikatny
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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7
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Sonkar K, Ayyappan V, Tressler CM, Adelaja O, Cai R, Cheng M, Glunde K. Focus on the glycerophosphocholine pathway in choline phospholipid metabolism of cancer. NMR IN BIOMEDICINE 2019; 32:e4112. [PMID: 31184789 PMCID: PMC6803034 DOI: 10.1002/nbm.4112] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 04/16/2019] [Accepted: 04/20/2019] [Indexed: 05/02/2023]
Abstract
Activated choline metabolism is a hallmark of carcinogenesis and tumor progression, which leads to elevated levels of phosphocholine and glycerophosphocholine in all types of cancer tested so far. Magnetic resonance spectroscopy applications have played a key role in detecting these elevated choline phospholipid metabolites. To date, the majority of cancer-related studies have focused on phosphocholine and the Kennedy pathway, which constitutes the biosynthesis pathway for membrane phosphatidylcholine. Fewer and more recent studies have reported on the importance of glycerophosphocholine in cancer. In this review article, we summarize the recent literature on glycerophosphocholine metabolism with respect to its cancer biology and its detection by magnetic resonance spectroscopy applications.
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Affiliation(s)
- Kanchan Sonkar
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of Cancer Imaging Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Vinay Ayyappan
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of Cancer Imaging Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Caitlin M. Tressler
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of Cancer Imaging Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Oluwatobi Adelaja
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of Cancer Imaging Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Ruoqing Cai
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of Cancer Imaging Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Menglin Cheng
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of Cancer Imaging Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Kristine Glunde
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of Cancer Imaging Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- The Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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8
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Detection and Differentiation of Breast Cancer Sub-Types using a cPLA2α Activatable Fluorophore. Sci Rep 2019; 9:6122. [PMID: 30992473 PMCID: PMC6467920 DOI: 10.1038/s41598-019-41626-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Accepted: 02/01/2019] [Indexed: 12/26/2022] Open
Abstract
Cytosolic phospholipase A2α (cPLA2α) has been shown to be elevated in breast cancer and is a potential biomarker in the differentiation of molecular sub-types. Using a cPLA2α activatable fluorophore, DDAO arachidonate, we explore its ability to function as a contrast agent in fluorescence-guided surgery. In cell lines ranging in cPLA2α expression and representing varying breast cancer sub-types, we show DDAO arachidonate activates with a high correlation to cPLA2α expression level. Using a control probe, DDAO palmitate, in addition to cPLA2α inhibition and genetic knockdown, we show that this activation is a result of cPLA2α activity. In mouse models, using an ex vivo tumor painting technique, we show that DDAO arachidonate activates to a high degree in basal-like versus luminal-like breast tumors and healthy mammary tissue. Finally, we show that using an in vivo model, orthotopic basal-like tumors give significantly high probe activation compared to healthy mammary fat pads and surrounding tissue. Together we conclude that cPLA2α activatable fluorophores such as DDAO arachidonate may serve as a useful contrast agent for the visualization of tumor margins in the fluorescence-guided surgery of basal-like breast cancer.
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9
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Liebov B, Arroyo AD, Rubtsova NI, Osharovich SA, Delikatny EJ, Popov AV. Nonprotecting Group Synthesis of a Phospholipase C Activatable Probe with an Azo-Free Quencher. ACS OMEGA 2018; 3:6867-6873. [PMID: 29978148 PMCID: PMC6026834 DOI: 10.1021/acsomega.8b00635] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 06/18/2018] [Indexed: 06/08/2023]
Abstract
The near-infrared fluorescent activatable smart probe Pyro-phosphatidylethanolamine (PtdEtn)-QSY was synthesized and observed to selectively fluoresce in the presence of phosphatidylcholine-specific phospholipase C (PC-PLC). PC-PLC is an important biological target as it is known to be upregulated in a variety of cancers, including triple negative breast cancer. Pyro-PtdEtn-QSY features a QSY21 quenching moiety instead of the Black Hole Quencher-3 (BHQ-3) used previously because the latter contains an azo bond, which could lead to biological instability.
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10
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Stallivieri A, Colombeau L, Devy J, Etique N, Chaintreuil C, Myrzakhmetov B, Achard M, Baros F, Arnoux P, Vanderesse R, Frochot C. New photodynamic molecular beacons (PMB) as potential cancer-targeted agents in PDT. Bioorg Med Chem 2018; 26:688-702. [DOI: 10.1016/j.bmc.2017.12.034] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 12/19/2017] [Accepted: 12/22/2017] [Indexed: 11/16/2022]
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11
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Alekseeva A, Tretiakova D, Chernikov V, Utkin Y, Molotkovsky J, Vodovozova E, Boldyrev I. Heterodimeric V. nikolskii phospholipases A2 induce aggregation of the lipid bilayer. Toxicon 2017; 133:169-179. [DOI: 10.1016/j.toxicon.2017.05.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 05/12/2017] [Accepted: 05/15/2017] [Indexed: 11/16/2022]
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12
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Meares A, Satraitis A, Akhigbe J, Santhanam N, Swaminathan S, Ehudin M, Ptaszek M. Amphiphilic BODIPY-Hydroporphyrin Energy Transfer Arrays with Broadly Tunable Absorption and Deep Red/Near-Infrared Emission in Aqueous Micelles. J Org Chem 2017; 82:6054-6070. [PMID: 28516773 PMCID: PMC5873324 DOI: 10.1021/acs.joc.7b00357] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BODIPY-hydroporphyrin energy transfer arrays allow for development of a family of fluorophores featuring a common excitation band at 500 nm, tunable excitation band in the deep red/near-infrared window, and tunable emission. Their biomedical applications are contingent upon retaining their optical properties in an aqueous environment. Amphiphilic arrays containing PEG-substituted BODIPY and chlorins or bacteriochlorins were prepared and their optical and fluorescence properties were determined in organic solvents and aqueous surfactants. The first series of arrays contains BODIPYs with PEG substituents attached to the boron, whereas in the second series, PEG substituents are attached to the aryl at the meso positions of BODIPY. For both series of arrays, excitation of BODIPY at 500 nm results in efficient energy transfer to and bright emission of hydroporphyrin in the deep-red (640-660 nm) or near-infrared (740-760 nm) spectral windows. In aqueous solution of nonionic surfactants (Triton X-100 and Tween 20) arrays from the second series exhibit significant quenching of fluorescence, whereas properties of arrays from the first series are comparable to those observed in polar organic solvents. Reported arrays possess large effective Stokes shift (115-260 nm), multiple excitation wavelengths, and narrow, tunable deep-red/near-IR fluorescence in aqueous surfactants, and are promising candidates for a variety of biomedical-related applications.
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Affiliation(s)
- Adam Meares
- University of Maryland, Baltimore County , 1000 Hilltop Circle, Baltimore, 21250 Maryland, United States
| | - Andrius Satraitis
- University of Maryland, Baltimore County , 1000 Hilltop Circle, Baltimore, 21250 Maryland, United States
| | - Joshua Akhigbe
- University of Maryland, Baltimore County , 1000 Hilltop Circle, Baltimore, 21250 Maryland, United States
| | - Nithya Santhanam
- University of Maryland, Baltimore County , 1000 Hilltop Circle, Baltimore, 21250 Maryland, United States
| | - Subramani Swaminathan
- University of Maryland, Baltimore County , 1000 Hilltop Circle, Baltimore, 21250 Maryland, United States
| | - Melanie Ehudin
- University of Maryland, Baltimore County , 1000 Hilltop Circle, Baltimore, 21250 Maryland, United States
| | - Marcin Ptaszek
- University of Maryland, Baltimore County , 1000 Hilltop Circle, Baltimore, 21250 Maryland, United States
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13
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Subramaniam R, Jagadeesan R, Mathew I, Cen Y, Balaz S. Scalable Synthesis and Purification of Acetylated Phosphatidyl Choline Headgroup. Org Process Res Dev 2017; 21:177-181. [PMID: 30792570 DOI: 10.1021/acs.oprd.6b00261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The acetylated headgroup of the most abundant mammalian phospholipid, 1,2-diacetyl-3-sn-phosphatidyl choline (DAcPC), has several important applications in research. For instance, it can be dissolved in the same amount of water as in the fluid PC bilayer, to create a surrogate of a PC headgroup stratum, for studying solvation of small molecules and the influence of their structure on the process. In contrast to PC derivatives with longer acyl chains, DAcPC does not self-aggregate, rendering the aqueous solution homogeneous and suitable for simplified analyses of interactions of molecules with the headgroups. Several studies have been published where DAcPC was used in a crudely purified form. Here we describe a one-step preparation of DAcPC from commercially available bulk chemicals and purification of the product by crystallization and washing. The process gives a good yield and is easily scalable. The availability of enantiopure, crystalline DAcPC could open the door to more extensive biochemical, pharmacological, and nutritional studies of this interesting chemical.
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Affiliation(s)
- Rajesh Subramaniam
- Department of Pharmaceutical Sciences, Vermont Campus, Albany College of Pharmacy and Health Sciences, 261 Mountain View Drive, Colchester, Vermont 05446, Unites States
| | - Ramesh Jagadeesan
- Pharmaceutical Development Unit, Kemwell Biopharma Pvt Ltd, 34 Tumkur Road, T-Begur, Nelamangala, Bangalore Rural-562123, India
| | - Iswarya Mathew
- Department of Pharmaceutical Sciences, Vermont Campus, Albany College of Pharmacy and Health Sciences, 261 Mountain View Drive, Colchester, Vermont 05446, Unites States
| | - Yana Cen
- Department of Pharmaceutical Sciences, Vermont Campus, Albany College of Pharmacy and Health Sciences, 261 Mountain View Drive, Colchester, Vermont 05446, Unites States
| | - Stefan Balaz
- Department of Pharmaceutical Sciences, Vermont Campus, Albany College of Pharmacy and Health Sciences, 261 Mountain View Drive, Colchester, Vermont 05446, Unites States
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Mishra OP, Popov AV, Pietrofesa RA, Christofidou-Solomidou M. Gamma-irradiation produces active chlorine species (ACS) in physiological solutions: Secoisolariciresinol diglucoside (SDG) scavenges ACS - A novel mechanism of DNA radioprotection. Biochim Biophys Acta Gen Subj 2016; 1860:1884-97. [PMID: 27261092 PMCID: PMC5253237 DOI: 10.1016/j.bbagen.2016.05.037] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 05/13/2016] [Accepted: 05/26/2016] [Indexed: 11/28/2022]
Abstract
Background Secoisolariciresinol diglucoside (SDG), the main lignan in whole grain flaxseed, is a potent antioxidant and free radical scavenger with known radioprotective properties. However, the exact mechanism of SDG radioprotection is not well understood. The current study identified a novel mechanism of DNA radioprotection by SDG in physiological solutions by scavenging active chlorine species (ACS) and reducing chlorinated nucleobases. Methods The ACS scavenging activity of SDG was determined using two highly specific fluoroprobes: hypochlorite-specific 3′-(p-aminophenyl) fluorescein (APF) and hydroxyl radical-sensitive 3′-(p-hydroxyphenyl) fluorescein (HPF). Dopamine, an SDG structural analog, was used for proton 1H NMR studies to trap primary ACS radicals. Taurine N-chlorination was determined to demonstrate radiation-induced generation of hypochlorite, a secondary ACS. DNA protection was assessed by determining the extent of DNA fragmentation and plasmid DNA relaxation following exposure to ClO− and radiation. Purine base chlorination by ClO− and γ-radiation was determined by using 2-aminopurine (2-AP), a fluorescent analog of 6-aminopurine. Results: Chloride anions (Cl−) consumed >90% of hydroxyl radicals in physiological solutions produced by γ-radiation resulting in ACS formation, which was detected by 1H NMR. Importantly, SDG scavenged hypochlorite- and γ-radiation-induced ACS. In addition, SDG blunted ACS-induced fragmentation of calf thymus DNA and plasmid DNA relaxation. SDG treatment before or after ACS exposure decreased the ClO− or γ-radiation-induced chlorination of 2-AP. Exposure to γ-radiation resulted in increased taurine chlorination, indicative of ClO− generation. NMR studies revealed formation of primary ACS radicals (chlorine atoms (Cl•) and dichloro radical anions (Cl2−•)), which were trapped by SDG and its structural analog dopamine. Conclusion We demonstrate that γ-radiation induces the generation of ACS in physiological solutions. SDG treatment scavenged ACS and prevented ACS-induced DNA damage and chlorination of 2-aminopurine. This study identified a novel and unique mechanism of SDG radioprotection, through ACS scavenging, and supports the potential usefulness of SDG as a radioprotector and mitigator for radiation exposure as part of cancer therapy or accidental exposure.
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Affiliation(s)
- Om P Mishra
- Department of Medicine, Pulmonary, Allergy and Critical Care Division, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, United States.
| | - Anatoliy V Popov
- Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, United States.
| | - Ralph A Pietrofesa
- Department of Medicine, Pulmonary, Allergy and Critical Care Division, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, United States.
| | - Melpo Christofidou-Solomidou
- Department of Medicine, Pulmonary, Allergy and Critical Care Division, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, United States.
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15
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Chiorazzo MG, Bloch NB, Popov AV, Delikatny EJ. Synthesis and Evaluation of Cytosolic Phospholipase A(2) Activatable Fluorophores for Cancer Imaging. Bioconjug Chem 2015; 26:2360-70. [PMID: 26426140 DOI: 10.1021/acs.bioconjchem.5b00417] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Activatable fluorophores selective to cytosolic phospholipase A2 (cPLA2) were synthesized and evaluated for their ability to image triple negative breast cancer cells. The activatable constructs were synthesized by esterification of a small molecule fluorophore with a fatty acid resulting in ablated fluorescence. Selectivity for cPLA2 was generated through the choice of fluorophore and fatty acid. Esterification with arachidonic acid was sufficient to impart specificity to cPLA2 when compared to esterification with palmitic acid. In vitro analysis of probes incorporated into phosphatidylcholine liposomes demonstrated that a nonselective phospholipase (sPLA2 group IB) was able to hydrolyze both arachidonate and palmitate coupled fluorophores resulting in the generation of fluorescence. Of the four fluorophores tested, DDAO (7-hydroxy-9H-(1,3-dichloro-9,9-dimethylacridin-2-one)) was observed to perform optimally in vitro and was analyzed further in 4175-Luc+ cells, a metastatic triple negative human breast cancer cell line expressing high levels of cPLA2. In contrast to the in vitro analysis, DDAO arachidonate was shown to activate selectively in 4175-Luc+ cells compared to the control DDAO palmitate as measured by fluorescence microscopy and quantitated with fluorescence spectroscopy. The addition of two agents known to activate cPLA2 enhanced DDAO arachidonate fluorescence without inducing any change to DDAO palmitate. Inhibition of cPLA2 resulted in reduced fluorescence of DDAO arachidonate but not DDAO palmitate. Together, we report the synthesis of a cPLA2 selective activatable fluorophore capable of detecting cPLA2 in triple negative breast cancer cells.
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Affiliation(s)
- Michael G Chiorazzo
- Department of Pharmacology, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States.,Department of Radiology, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Noah B Bloch
- Department of Radiology, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Anatoliy V Popov
- Department of Radiology, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Edward J Delikatny
- Department of Radiology, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
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16
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Meares A, Satraitis A, Santhanam N, Yu Z, Ptaszek M. Deep-red emissive BODIPY-chlorin arrays excitable with green and red wavelengths. J Org Chem 2015; 80:3858-69. [PMID: 25803423 DOI: 10.1021/acs.joc.5b00119] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
We report here the synthesis and characterization of BODIPY-chlorin arrays containing a chlorin subunit, with tunable deep-red (641-685 nm) emission, and one or two BODIPY moieties, absorbing at 504 nm. Two types of arrays were examined: one where BODIPY moieties are attached through a phenylacetylene linker at the 13- or 3,13-positions of chlorin, and a second type where BODIPY is attached at the 10-position of chlorin through an amide linker. Each of the examined arrays exhibits an efficient (≥0.80) energy transfer from BODIPY to the chlorin moiety in both toluene and DMF and exhibits intense fluorescence of chlorin upon excitation of BODIPY at ∼500 nm. Therefore, the effective Stokes shift in such arrays is in the range of 140-180 nm. Dyads with BODIPY attached at the 10-position of chlorin exhibit a bright fluorescence in a range of solvents with different polarities (i.e., toluene, MeOH, DMF, and DMSO). In contrast to this, some of the arrays in which BODIPY is attached at the 3- or at both 3,13-positons of chlorin exhibit significant reduction of fluorescence in polar solvents. Overall, dyads where BODIPY is attached at the 10-position of chlorin exhibit ∼5-fold brighter fluorescence than corresponding chlorin monomers, upon excitation at 500 nm.
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Affiliation(s)
- Adam Meares
- Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, Maryland 21250, United States
| | - Andrius Satraitis
- Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, Maryland 21250, United States
| | - Nithya Santhanam
- Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, Maryland 21250, United States
| | - Zhanqian Yu
- Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, Maryland 21250, United States
| | - Marcin Ptaszek
- Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, Maryland 21250, United States
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1,7-Bis-( N, N-dialkylamino)perylene Bisimides: Facile Synthesis and Characterization as Near-Infrared Fluorescent Dyes. MATERIALS 2014; 7:7548-7565. [PMID: 28788262 PMCID: PMC5512673 DOI: 10.3390/ma7117548] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 11/10/2014] [Accepted: 11/13/2014] [Indexed: 01/09/2023]
Abstract
Three symmetric alkylamino-substituted perylene bisimides with different n-alkyl chain lengths (n = 6, 12, or 18), 1,7-bis-(N,N-dialkylamino)perylene bisimides (1a–1c), were synthesized under mild condition and were characterized by 1H NMR, 13C NMR and high resolution mass spectroscopy. Their optical and electrochemical properties were measured using UV-Vis and emission spectroscopic techniques as well as cyclic voltammetry (CV). These compounds show deep green color in both solution and solid state, and are highly soluble in dichloromethane and even in nonpolar solvents such as hexane. The shapes of the absorption spectra of 1a–1c in the solution and solid state were found to be almost the same, indicating that the long alkyl chains could efficiently prevent intermolecular contact and aggregation. They show a unique charge transfer emission in the near-infrared region, of which the peak wavelengths exhibit strong solvatochromism. The dipole moments of the molecules have been estimated using the Lippert–Mataga equation, and upon excitation, they show larger dipole moment changes than that of 1,7-diaminoperylene bisimide (2). Moreover, all the dyes exhibit two irreversible one-electron oxidations and two quasi-reversible one-electron reductions in dichloromethane at modest potentials. Complementary density functional theory calculations performed on these chromophores are reported in order to rationalize their electronic structure and optical properties.
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Anikeeva N, Sykulev Y, Delikatny EJ, Popov AV. Core-based lipid nanoparticles as a nanoplatform for delivery of near-infrared fluorescent imaging agents. AMERICAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING 2014; 4:507-524. [PMID: 25250201 PMCID: PMC4171838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 08/06/2014] [Indexed: 06/03/2023]
Abstract
Pyropheophorbide a (Pyro) is a near-infrared (NIR) fluorescent dye and photosensitizer with high quantum yield that makes the dye suitable for tumor treatment both as an imaging and therapy agent. We have designed and synthesized a series of a Pyro-based NIR probes, based on the conjugation of Pyro with lipids. The nature of our probes requires the use of a lipophilic carrier to deliver the probes to cancer cell membranes. To address this, we have utilized lipid-based nanoparticles (LNPs) consisting of PEGylated lipids, which form the nanoparticle shell, and a lipid core. To endow the LNPs with targeting properties, nitrilotriacetic acid (NTA) lipids were included in the composition that enables the non-covalent attachment of His-tag targeting proteins preserving their functional activity. We found that the nature of the core molecules influence the nanoparticle size, shelf-life and stability at physiological temperature. Two different Pyro-lipid conjugates were loaded either into the core or shell of the LNPs. The conjugates revealed differential ability to be accumulated in the cell membrane of the target cells with time. Thus, the modular organization of the core-shell LNPs allows facile adjustment of their composition with goal to fine tuning the nanoparticle properties for in vivo application.
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Affiliation(s)
- Nadia Anikeeva
- Department of Microbiology and Immunology and Kimmel Cancer Center, Thomas Jefferson UniversityPhiladelphia, Pennsylvania, USA
| | - Yuri Sykulev
- Department of Microbiology and Immunology and Kimmel Cancer Center, Thomas Jefferson UniversityPhiladelphia, Pennsylvania, USA
| | - Edward J Delikatny
- Department of Radiology, Perelman School of Medicine, University of PennsylvaniaPhiladelphia, Pennsylvania, USA
| | - Anatoliy V Popov
- Department of Radiology, Perelman School of Medicine, University of PennsylvaniaPhiladelphia, Pennsylvania, USA
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Ptaszek M. Rational design of fluorophores for in vivo applications. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 113:59-108. [PMID: 23244789 DOI: 10.1016/b978-0-12-386932-6.00003-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Several classes of small organic molecules exhibit properties that make them suitable for fluorescence in vivo imaging. The most promising candidates are cyanines, squaraines, boron dipyrromethenes, porphyrin derivatives, hydroporphyrins, and phthalocyanines. The recent designing and synthetic efforts have been dedicated to improving their optical properties (shift the absorption and emission maxima toward longer wavelengths and increase the brightness) as well as increasing their stability and water solubility. The most notable advances include development of encapsulated cyanine dyes with increased stability and water solubility, squaraine rotaxanes with increased stability, long-wavelength-absorbing boron dipyrromethenes, long-wavelength-absorbing porphyrin and hydroporphyrin derivatives, and water-soluble phthalocyanines. Recent advances in luminescence and bioluminescence have made self-illuminating fluorophores available for in vivo applications. Development of new types of hydroporphyrin energy-transfer dyads gives the promise for further advances in in vivo multicolor imaging.
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Affiliation(s)
- Marcin Ptaszek
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, Maryland, USA
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Yu Z, Ptaszek M. Near-IR emissive chlorin-bacteriochlorin energy-transfer dyads with a common donor and acceptors with tunable emission wavelength. J Org Chem 2013; 78:10678-91. [PMID: 24079536 DOI: 10.1021/jo4016858] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Design, synthesis, and optical properties of a series of novel chlorin-bacteriochlorin energy transfer dyads are described. Each dyad is composed of a common red-absorbing (645-646 nm) chlorin, as an energy donor, and a different near-IR emitting bacteriochlorin, as an energy acceptor. Each bacteriochlorin acceptor is equipped with a different set of auxochromes, so that each of them emits at a different wavelength. Dyads exhibit an efficient energy transfer (≥0.77) even for chlorin-bacteriochlorin pairs with large (up to 122 nm) separation between donor emission and acceptor absorption. Excitation of the chlorin donor results in relatively strong emission of the bacteriochlorin acceptor, with a quantum yield Φf range of 0.155-0.23 in toluene and 0.12-0.185 in DMF. The narrow, tunable emission band of bacteriochlorins enables the selection of a series of three dyads with well-resolved emissions at 732, 760, and 788 nm, and common excitation at 645 nm. Selected dyads have been also converted into bioconjugatable N-succinamide ester derivatives. The optical properties of the described dyads make them promising candidates for development of a family of near-IR fluorophores for simultaneous imaging of multiple targets, where the whole set of fluorophores can be excited with the common wavelength, and fluorescence from each can be independently detected.
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Affiliation(s)
- Zhanqian Yu
- Department of Chemistry and Biochemistry, University of Maryland, Baltimore County , 1000 Hilltop Circle, Baltimore, Maryland 21250, United States
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Chen WY, Chen LY, Ou CM, Huang CC, Wei SC, Chang HT. Synthesis of fluorescent gold nanodot-liposome hybrids for detection of phospholipase C and its inhibitor. Anal Chem 2013; 85:8834-40. [PMID: 23964669 DOI: 10.1021/ac402043t] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We report the synthesis of fluorescent 11-mercaptoundecanoic acid-gold nanodot-liposome (11-MUA-Au ND/Lip) hybrids by incorporation of gold nanoparticles (∼3 nm) and 11-MUA molecules in hydrophobic phospholipid membranes that self-assemble to form small unilamellar vesicles. A simple and homogeneous fluorescence assay for phospholipase C (PLC) was developed on the basis of the fluorescence quenching of 11-MUA-Au ND/Lip hybrids in aqueous solution. The fluorescence of the 11-MUA-Au ND/Lip hybrids is quenched by oxygen (O2) molecules in solution, and quenching is reduced in the presence of PLC. PLC catalyzes the hydrolysis of phosphatidylcholine units from Lip to yield diacylglycerol (DAG) and phosphocholine (PC) products, leading to the decomposition of Lip. The diacylglycerol further interacts with 11-MUA-Au NDs via hydrophobic interactions, leading to inhibition of O2 quenching. The 11-MUA-Au ND/Lip probe provides a limit of detection (at a signal-to-noise ratio of 3) of 0.21 nM for PLC, with high selectivity over other proteins, enzymes, and phospholipases. We have validated the practicality of using this probe for the determination of PLC concentrations in breast cancer cells (MCF-7 and MDA-MB-231 cell lines) and nontumor cells (MCF-10A cell line), revealing that the PLC activity in the first two is at least 1.5-fold higher than that in the third. An inhibitor assay using 11-MUA-Au ND/Lip hybrids demonstrated that tricyclodecan-9-yl potassium xanthate (D609) inhibits PLC (10 nM) with an IC50 value of 3.81 ± 0.22 μM. This simple, sensitive, and selective approach holds great potential for detection of PLC in cancer cells and for the screening of anti-PLC drugs.
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Affiliation(s)
- Wei-Yu Chen
- Department of Chemistry, National Taiwan University , Taipei 10617, Taiwan
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Yuan L, Lin W, Zheng K, He L, Huang W. Far-red to near infrared analyte-responsive fluorescent probes based on organic fluorophore platforms for fluorescence imaging. Chem Soc Rev 2013; 42:622-61. [DOI: 10.1039/c2cs35313j] [Citation(s) in RCA: 1456] [Impact Index Per Article: 132.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Chevalier A, Massif C, Renard PY, Romieu A. Bioconjugatable Azo-Based Dark-Quencher Dyes: Synthesis and Application to Protease-Activatable Far-Red Fluorescent Probes. Chemistry 2012; 19:1686-99. [DOI: 10.1002/chem.201203427] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Indexed: 11/08/2022]
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Lovell JF, Jin CS, Huynh E, MacDonald TD, Cao W, Zheng G. Enzymatic Regioselection for the Synthesis and Biodegradation of Porphysome Nanovesicles. Angew Chem Int Ed Engl 2012; 51:2429-33. [DOI: 10.1002/anie.201108280] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Revised: 12/15/2011] [Indexed: 11/06/2022]
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Lovell JF, Jin CS, Huynh E, MacDonald TD, Cao W, Zheng G. Enzymatic Regioselection for the Synthesis and Biodegradation of Porphysome Nanovesicles. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201108280] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Cleavable linkers in chemical biology. Bioorg Med Chem 2012; 20:571-82. [DOI: 10.1016/j.bmc.2011.07.048] [Citation(s) in RCA: 157] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 07/08/2011] [Accepted: 07/23/2011] [Indexed: 01/11/2023]
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Strianese M, Staiano M, Ruggiero G, Labella T, Pellecchia C, D'Auria S. Fluorescence-based biosensors. Methods Mol Biol 2012; 875:193-216. [PMID: 22573441 DOI: 10.1007/978-1-61779-806-1_9] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The field of optical sensors has been a growing research area over the last three decades. A wide range of books and review articles has been published by experts in the field who have highlighted the advantages of optical sensing over other transduction methods. Fluorescence is by far the method most often applied and comes in a variety of schemes. Nowadays, one of the most common approaches in the field of optical biosensors is to combine the high sensitivity of fluorescence detection in combination with the high selectivity provided by ligand-binding proteins. In this chapter we deal with reviewing our recent results on the implementation of fluorescence-based sensors for monitoring environmentally hazardous gas molecules (e.g. nitric oxide, hydrogen sulfide). Reflectivity-based sensors, fluorescence correlation spectroscopy-based (FCS) systems, and sensors relying on the enhanced fluorescence emission on silver island films (SIFs) coupled to the total internal reflection fluorescence mode (TIRF) for the detection of gliadin and other prolamines considered toxic for celiac patients are also discussed herein.
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Affiliation(s)
- Maria Strianese
- Department of Chemistry, University of Salerno, Salerno, Italy
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Mawn TM, Popov AV, Beardsley NJ, Stefflova K, Milkevitch M, Zheng G, Delikatny EJ. In vivo detection of phospholipase C by enzyme-activated near-infrared probes. Bioconjug Chem 2011; 22:2434-43. [PMID: 22034913 PMCID: PMC3292874 DOI: 10.1021/bc200242v] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this article, the characterization of the first near-infrared (NIR) phospholipase-activated molecular beacon is reported, and its utility for in vivo cancer imaging is demonstrated. The probe consists of three elements: a phospholipid (PL) backbone to which the NIR fluorophore, pyropheophorbide a (Pyro), and the NIR Black Hole Quencher 3 (BHQ) were conjugated. Because of the close proximity of BHQ to Pyro, the Pyro-PtdEtn-BHQ probe is self-quenched until enzyme hydrolysis releases the fluorophore. The Pyro-PtdEtn-BHQ probe is highly specific to one isoform of phospholipase C, phosphatidylcholine-specific phospholipase C (PC-PLC), responsible for catabolizing phosphatidylcholine directly to phosphocholine. Incubation of Pyro-PtdEtn-BHQ in vitro with PC-PLC demonstrated a 150-fold increase in fluorescence that could be inhibited by the specific PC-PLC inhibitor tricyclodecan-9-yl xanthogenate (D609) with an IC(50) of 34 ± 8 μM. Since elevations in phosphocholine have been consistently observed by magnetic resonance spectroscopy in a wide array of cancer cells and solid tumors, we assessed the utility of Pyro-PtdEtn-BHQ as a probe for targeted tumor imaging. Injection of Pyro-PtdEtn-BHQ into mice bearing DU145 human prostate tumor xenografts followed by in vivo NIR imaging resulted in a 4-fold increase in tumor radiance over background and a 2 fold increase in the tumor/muscle ratio. Tumor fluorescence enhancement was inhibited with the administration of D609. The ability to image PC-PLC activity in vivo provides a unique and sensitive method of monitoring one of the critical phospholipase signaling pathways activated in cancer, as well as the phospholipase activities that are altered in response to cancer treatment.
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Affiliation(s)
- Theresa M. Mawn
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104
| | - Anatoliy V. Popov
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104
| | - Nancy J. Beardsley
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104
| | | | | | | | - E. James Delikatny
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104
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Mawn TM, Popov AV, Delikatny EJ. A quantitative continuous enzyme assay of intramolecularly quenched fluorogenic phospholipase substrates for molecular imaging. Anal Biochem 2011; 422:96-102. [PMID: 22230285 DOI: 10.1016/j.ab.2011.12.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2011] [Revised: 12/01/2011] [Accepted: 12/03/2011] [Indexed: 11/29/2022]
Abstract
There has been recent growth in the development of activatable near-infrared (NIR) fluorescent probes for molecular imaging, generally designed by placing fluorochromes on a cleavable substrate in close proximity to one another, such that they self-quench, but fluoresce on separation via enzymatic cleavage of the substrate. Although these probes offer excellent contrast, the detection of enzyme activity has largely only been described qualitatively. In order to assess the effectiveness of a probe, it is useful to have a quantitative measure, such as the enzyme-substrate kinetic parameters. We have developed an assay to determine kinetic parameters and applied it to an intramolecularly quenched molecule, Pyro-PtdEtn-BHQ, a NIR fluorescent probe specific to phosphatidylcholine-specific phospholipase C. The development of this assay includes corrections for intermolecular quenching, calibration, optimization of reaction mixtures, and determination of kinetic and inhibition parameters. This assay can easily be extended to analyze and compare the efficiency of other fluorescent activatable phospholipase probes as suitable molecular imaging agents.
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Affiliation(s)
- Theresa M Mawn
- Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA
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