Kening Wu

Sun Yat-Sen University of Medical Sciences, Shengcheng, Guangdong, China

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Publications (4)12.97 Total impact

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    ABSTRACT: The synthetic bis(zinc(II)-dipicolylamine) (DPAZn2) coordination complexes are known to have a high specific and selective affinity to target the exposed phosphatidylserine (PS) on the surface of dead and dying cells. An (18)F-labeled DPAZn2 complex (4-(18)F-Fluoro-benzoyl-bis(zinc(II)-dipicolylamine), (18)F-FB-DPAZn2) as positron emission tomography (PET) tracer was developed and evaluated for in vivo imaging of tumor treated with a chemical agent. The in vitro cell stain studies revealed that fluorescent DPAZn2 complexes (Dansyl-DPAZn2) stained the same cells (apoptotic and necrotic cells) as fluorescein isothiocyanate (FITC) labeled Annexin V (FITC-Annexin V). The radiosynthesis of (18)F-FB-DPAZn2 was achieved through the amidation the precursor bis(2,2'-dipicolylamine) derivative (DPA2) with the prosthetic group N-succinimidyl-4-[(18)F]-fluorobenzoate ((18)F-SFB) and chelation with zinc nitrate. In the biodistribution study, the fast clearance of (18)F-FB-DPAZn2 from blood and kidney was observed and high uptake in liver and intestine within 90 min postinjection was also found. For the PET imaging, significantly higher tumor uptake of (18)F-FB-DPAZn2 was observed in the adriamycin (ADM)-treated Hepa1-6 hepatocellular carcinoma-bearing mice than that in the untreated tumor-model mice, while a slightly decreased tumor uptake of (18)F-FDG was found in the ADM-treated tumor-bearing mice. The results indicate that (18)F-FB-DPAZn2 has the similar capability of apoptosis detection as FITC-Annexin V and seems to be a potential PET tracer for noninvasive evaluation and monitoring of anti-tumor chemotherapy. The high uptake of (18)F-FB-DPAZn2 in the abdomen needs to optimize the structure for improving its pharmacokinetics characteristics in the future work.
    Apoptosis 04/2013; DOI:10.1007/s10495-013-0852-4 · 3.61 Impact Factor
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    ABSTRACT: The potential value of multiplexed positron emission tomography (PET) tracers in mice with turpentine-induced inflammation was evaluated and compared with 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG) for glucose metabolism imaging. These PET tracers included [18F]fluoromethylcholine ([18F]FCH) for choline metabolism imaging, (S-[11C]methyl)-D-cysteine ([11C]DMCYS) for amino acid metabolism imaging, [11C]bis(zinc(II)-dipicolylamine) ([11C]DPA-Zn2+) for apoptosis imaging, 2-(4-N-[11C]-methylaminophenyl)-6-hydroxybenzothiazole ([11C]PIB) for β amyloid binding imaging, and [18F]fluoride (18F−) for bone metabolism imaging. In mice with turpentine-induced inflammation mice, the biodistribution of all the tracers mentioned above at 5, 15, 30, 45, and 60 min postinjection was determined. Also, the time-course curves of the tracer uptake ratios for inflammatory thigh muscle (IM) to normal uninflammatory thigh muscle (NM), IM to blood (BL), IM to brain (BR), and IM to liver (LI) were acquired, respectively. Moreover, PET imaging with the tracers within 60 min postinjection on a clinical PET/CT scanner was also conducted. [18F]FDG and 18F− showed relatively higher uptake ratios for IM to NM, IM to BL, IM to BR, and IM to LI than [18F]FCH, [11C]DPA-Zn2+, [11C]DMCYS and [11C]PIB, which were highly consistent with the results delineated in PET images. The results demonstrate that 18F− seems to be a potential PET tracer for inflammation imaging. [18F]FCH and [11C]DMCYS, with lower accumulation in inflammatory tissue than [18F]FDG, are not good PET tracers for inflammation imaging. As a promising inflammatory tracer, the chemical structure of [11C]DPA-Zn2+ needs to be further optimized.
    Molecules 12/2012; 17(12):13948-59. DOI:10.3390/molecules171213948 · 2.42 Impact Factor
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    ABSTRACT: [C]methyl iodide ([C]CH3I) is the most extensively used methylation agent for the preparation of a majority of C-labeled positron emission tomography (PET) radiotracers, which is commonly produced by the wet method and the gas-phase method. On account of the complexity of the gas-phase method, a simple automated synthesis of [C]methyl bromide ([C]CH3Br) as an analog of [C]CH3I is derived by the wet method in this study. Radiosynthesis of L-[S-methyl-C]methionine (MET), L-[S-methyl-C]cysteine (MCYS), [N-methyl-C]choline (CH), [C]methyl triflate ([C]CH3OSO2CF3), and [C]-2-β-carbomethoxy-3-β-(4-fluorophenyl)-tropane (CFT) by methylation reaction with [C]CH3Br, and PET imaging of patients are also described. The preparation of [C]CH3Br by a one-pot wet method involved the following steps: reduction of [C]carbon dioxide with lithium aluminium hydride (LiAlH4) solution, treatment with hydrobromic acid, and distillation of [C]CH3Br under continuous nitrogen flow. [C]methylation of L-homocysteine thiolactone hydrochloride, L-cysteine, 2-dimethylaminoethanol, silver triflate, and nor-β-CFT as precursors with [C]CH3Br and purification with Sep-Pak cartridges gave MET, MCYS, CH, [C]CH3OSO2CF3, and CFT, respectively. In addition, PET imaging of brain cancer and Parkinson's disease was carried out. The uncorrected radiochemical yield of [C]CH3Br was (37.8±2.5%) based on [C]carbon dioxide within a total synthesis time of 10 min and the radiochemical purity of [C]CH3Br was greater than 95%. The uncorrected yields of MET, MCYS, CH, [C]CH3OSO2CF3, and CFT were 70.1±0.5%, 70.2±2.3%, 60.3±1.8%, 95.1±2.2%, and 60.1±1.5% (from [C]CH3OSO2CF3) within a total synthesis time of 2, 2, 5, 1, and 8 min, respectively. The radiochemical purity of MET, MCYS, CH, [C]CH3OSO2CF3, and CFT was more than 95%. Good PET images in the patients are obtained. Automated synthesis of [C]CH3Br can be done by the wet method on the commercial [C]CH3I synthesizer. [C]CH3Br can be used for a [C]methylation reaction to produce C-labeled tracers for clinical PET imaging.
    Nuclear Medicine Communications 06/2011; 32(6):466-74. DOI:10.1097/MNM.0b013e3283438f9a · 1.37 Impact Factor
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    ABSTRACT: S-(11)C-methyl-L-cysteine ((11)C-MCYS), an analog of S-(11)C-methyl-L-methionine ((11)C-MET), can potentially serve as an amino acid PET tracer for tumor imaging. The aim of this study was to investigate the radiosynthesis and perform a biologic evaluation of (11)C-MCYS as a tumor imaging tracer. The results of the first human PET study are reported. (11)C-MCYS was prepared by (11)C-methylation of the precursor L-cysteine with (11)CH(3)I and purification on commercial C18 cartridges. In vitro competitive inhibition experiments were performed with Hepa1-6 hepatoma cell lines, and biodistribution of (11)C-MCYS was determined in normal mice. The incorporation of (11)C-MCYS into tissue proteins was investigated. In vivo (11)C-MCYS uptake studies were performed on hepatocellular carcinoma-bearing nude mice and inflammation models and compared with (11)C-MET PET and (18)F-FDG PET. In a human PET study, a patient with a recurrence of glioma after surgery was examined with (11)C-MCYS PET and (18)F-FDG PET. The uncorrected radiochemical yield of (11)C-MCYS from (11)CH(3)I was more than 50% with a synthesis time of 2 min, the radiochemical purity of (11)C-MCYS was more than 99%, and the enantiomeric purity was more than 90%. In vitro studies showed that (11)C-MCYS transport was mediated through transport system L. Biodistribution studies demonstrated high uptake of (11)C-MCYS in the liver, stomach wall, and heart and low uptake of (11)C-MCYS in the brain. There was higher accumulation of (11)C-MCYS in the tumor than in the muscles. The tumor-to-muscle and inflammatory lesion-to-muscle ratios were 7.27 and 1.62, respectively, for (11)C-MCYS, 5.08 and 3.88, respectively, for (18)F-FDG, and 4.26 and 2.28, respectively, for (11)C-MET at 60 min after injection. Almost no (11)C-MCYS was incorporated into proteins. For the patient PET study, high uptake of (11)C-MCYS with true-positive results, but low uptake of (18)F-FDG with false-negative results, was found in the recurrent glioma. Automated synthesis of (11)C-MCYS is easy to perform. (11)C-MCYS is superior to (11)C-MET and (18)F-FDG in the differentiation of tumor from inflammation and seems to have potential as an oncologic PET tracer for the diagnosis of solid tumors.
    Journal of Nuclear Medicine 02/2011; 52(2):287-93. DOI:10.2967/jnumed.110.081349 · 5.56 Impact Factor

Publication Stats

21 Citations
12.97 Total Impact Points

Institutions

  • 2013
    • Sun Yat-Sen University of Medical Sciences
      Shengcheng, Guangdong, China
  • 2011–2012
    • Sun Yat-Sen University
      Shengcheng, Guangdong, China