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Tan XY, Li YT, Li HH, Ma LX, Zeng CM, Zhang TT, Huang TX, Zhao XD, Fu L. WNT2-SOX4 positive feedback loop promotes chemoresistance and tumorigenesis by inducing stem-cell like properties in gastric cancer. Oncogene 2023; 42:3062-3074. [PMID: 37634009 DOI: 10.1038/s41388-023-02816-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 08/14/2023] [Accepted: 08/18/2023] [Indexed: 08/28/2023]
Abstract
Gastric cancer (GC) is characterized by its vigorous chemoresistance to current therapies, which is attributed to the highly heterogeneous and immature phenotype of cancer stem cells (CSCs) during tumor initiation and progression. The secretory WNT2 ligand regulates multiple cancer pathways and has been demonstrated to be a potential therapeutic target for gastrointestinal tumors; however, its role involved in gastric CSCs (GCSCs) remains unclear. Here, we found that overexpression of WNT2 enhanced stemness properties to promote chemoresistance and tumorigenicity in GCSCs. Mechanistically, WNT2 was positively regulated by its transcription factor SOX4, and in turn, SOX4 was upregulated by the canonical WNT2/FZD8/β-catenin signaling pathway to form an auto-regulatory positive feedback loop, resulting in the maintenance of GCSCs self-renewal and tumorigenicity. Furthermore, simultaneous overexpression of both WNT2 and SOX4 was correlated with poor survival and reduced responsiveness to chemotherapy in clinical GC specimens. Blocking WNT2 using a specific monoclonal antibody significantly disrupted the WNT2-SOX4 positive feedback loop in GCSCs and enhanced the chemotherapeutic efficacy when synergized with the chemo-drugs 5-fluorouracil and oxaliplatin in a GCSC-derived mouse xenograft model. Overall, this study identified a novel WNT2-SOX4 positive feedback loop as a mechanism for GCSCs-induced chemo-drugs resistance and suggested that the WNT2-SOX4 axis may be a potential therapeutic target for gastric cancer treatment.
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Affiliation(s)
- Xiang-Yu Tan
- Guangdong Province Key Laboratory of Regional Immunity and Diseases, Department of Pharmacology and International Cancer Center, Shenzhen University Medical School, Shenzhen University, Shenzhen, 518055, Guangdong, China
| | - Yu-Ting Li
- Guangdong Province Key Laboratory of Regional Immunity and Diseases, Department of Pharmacology and International Cancer Center, Shenzhen University Medical School, Shenzhen University, Shenzhen, 518055, Guangdong, China
- Shenzhen University-Friedrich Schiller Universität Jena Joint PhD Program in Biomedical Sciences, Shenzhen University Medical School, Shenzhen University, Shenzhen, 518055, Guangdong, China
| | - Hua-Hui Li
- Guangdong Province Key Laboratory of Regional Immunity and Diseases, Department of Pharmacology and International Cancer Center, Shenzhen University Medical School, Shenzhen University, Shenzhen, 518055, Guangdong, China
- Shenzhen University-Friedrich Schiller Universität Jena Joint PhD Program in Biomedical Sciences, Shenzhen University Medical School, Shenzhen University, Shenzhen, 518055, Guangdong, China
| | - Li-Xiang Ma
- Guangdong Province Key Laboratory of Regional Immunity and Diseases, Department of Pharmacology and International Cancer Center, Shenzhen University Medical School, Shenzhen University, Shenzhen, 518055, Guangdong, China
| | - Chui-Mian Zeng
- Department of Endocrinology and Diabetes Center, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510080, Guangdong, China
| | - Tian-Tian Zhang
- Guangdong Province Key Laboratory of Regional Immunity and Diseases, Department of Pharmacology and International Cancer Center, Shenzhen University Medical School, Shenzhen University, Shenzhen, 518055, Guangdong, China
| | - Tu-Xiong Huang
- Guangdong Province Key Laboratory of Regional Immunity and Diseases, Department of Pharmacology and International Cancer Center, Shenzhen University Medical School, Shenzhen University, Shenzhen, 518055, Guangdong, China
| | - Xiao-Di Zhao
- Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, 710032, Shaanxi, China
| | - Li Fu
- Guangdong Province Key Laboratory of Regional Immunity and Diseases, Department of Pharmacology and International Cancer Center, Shenzhen University Medical School, Shenzhen University, Shenzhen, 518055, Guangdong, China.
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2
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Li YT, Tan XY, Ma LX, Li HH, Zhang SH, Zeng CM, Huang LN, Xiong JX, Fu L. Targeting LGSN restores sensitivity to chemotherapy in gastric cancer stem cells by triggering pyroptosis. Cell Death Dis 2023; 14:545. [PMID: 37612301 PMCID: PMC10447538 DOI: 10.1038/s41419-023-06081-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 08/07/2023] [Accepted: 08/16/2023] [Indexed: 08/25/2023]
Abstract
Gastric cancer (GC) is notoriously resistant to current therapies due to tumor heterogeneity. Cancer stem cells (CSCs) possess infinite self-renewal potential and contribute to the inherent heterogeneity of GC. Despite its crucial role in chemoresistance, the mechanism of stemness maintenance of gastric cancer stem cells (GCSCs) remains largely unknown. Here, we present evidence that lengsin, lens protein with glutamine synthetase domain (LGSN), a vital cell fate determinant, is overexpressed in GCSCs and is highly correlated with malignant progression and poor survival in GC patients. Ectopic overexpression of LGSN in GCSC-derived differentiated cells facilitated their dedifferentiation and treatment resistance by interacting with vimentin and inducing an epithelial-to-mesenchymal transition. Notably, genetic interference of LGSN effectively suppressed tumor formation by inhibiting GCSC stemness maintenance and provoking gasdermin-D-mediated pyroptosis through vimentin degradation/NLRP3 signaling. Depletion of LGSN combined with the chemo-drugs 5-fluorouracil and oxaliplatin could offer a unique and promising approach to synergistically rendering this deadly cancer eradicable in vivo. Our data place focus on the role of LGSN in GCSC regeneration and emphasize the critical importance of pyroptosis in battling GCSC.
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Affiliation(s)
- Yu-Ting Li
- Guangdong Province Key Laboratory of Regional Immunity and Diseases, Department of Pharmacology and International Cancer Center, Shenzhen University Medical School, Shenzhen University, Shenzhen, Guangdong, 518055, China
- Shenzhen University-Friedrich Schiller Universität Jena Joint PhD Program in Biomedical Sciences, Shenzhen University Medical School, Shenzhen, Guangdong, 518055, China
| | - Xiang-Yu Tan
- Guangdong Province Key Laboratory of Regional Immunity and Diseases, Department of Pharmacology and International Cancer Center, Shenzhen University Medical School, Shenzhen University, Shenzhen, Guangdong, 518055, China
| | - Li-Xiang Ma
- Guangdong Province Key Laboratory of Regional Immunity and Diseases, Department of Pharmacology and International Cancer Center, Shenzhen University Medical School, Shenzhen University, Shenzhen, Guangdong, 518055, China
| | - Hua-Hui Li
- Guangdong Province Key Laboratory of Regional Immunity and Diseases, Department of Pharmacology and International Cancer Center, Shenzhen University Medical School, Shenzhen University, Shenzhen, Guangdong, 518055, China
- Shenzhen University-Friedrich Schiller Universität Jena Joint PhD Program in Biomedical Sciences, Shenzhen University Medical School, Shenzhen, Guangdong, 518055, China
| | - Shu-Hong Zhang
- Guangdong Province Key Laboratory of Regional Immunity and Diseases, Department of Pharmacology and International Cancer Center, Shenzhen University Medical School, Shenzhen University, Shenzhen, Guangdong, 518055, China
| | - Chui-Mian Zeng
- Department of Endocrinology and Diabetes Center, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Liu-Na Huang
- Guangdong Province Key Laboratory of Regional Immunity and Diseases, Department of Pharmacology and International Cancer Center, Shenzhen University Medical School, Shenzhen University, Shenzhen, Guangdong, 518055, China
| | - Ji-Xian Xiong
- Guangdong Province Key Laboratory of Regional Immunity and Diseases, Department of Pharmacology and International Cancer Center, Shenzhen University Medical School, Shenzhen University, Shenzhen, Guangdong, 518055, China.
| | - Li Fu
- Guangdong Province Key Laboratory of Regional Immunity and Diseases, Department of Pharmacology and International Cancer Center, Shenzhen University Medical School, Shenzhen University, Shenzhen, Guangdong, 518055, China.
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Zhang YM, Zhang XR, Shao SM, Liu J, Zeng CM, Han Y. [A case of neonatal hereditary spherocytosis characterized by hydrops fetalis]. Zhonghua Er Ke Za Zhi 2020; 58:418-420. [PMID: 32392960 DOI: 10.3760/cma.j.cn112140-20200113-00030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Affiliation(s)
- Y M Zhang
- Department of Pediatrics, Peking University People's Hospital, Beijing 100044, China
| | - X R Zhang
- Department of Pediatrics, Peking University People's Hospital, Beijing 100044, China
| | - S M Shao
- Department of Pediatrics, Peking University People's Hospital, Beijing 100044, China
| | - J Liu
- Department of Pediatrics, Peking University People's Hospital, Beijing 100044, China
| | - C M Zeng
- Department of Pediatrics, Peking University People's Hospital, Beijing 100044, China
| | - Y Han
- Department of Pediatrics, Peking University People's Hospital, Beijing 100044, China
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Cao TT, Xiang D, Liu BL, Huang TX, Tan BB, Zeng CM, Wang ZY, Ming XY, Zhang LY, Jin G, Li F, Wu JL, Guan XY, Lu D, Fu L. FZD7 is a novel prognostic marker and promotes tumor metastasis via WNT and EMT signaling pathways in esophageal squamous cell carcinoma. Oncotarget 2017; 8:65957-65968. [PMID: 29029485 PMCID: PMC5630385 DOI: 10.18632/oncotarget.19586] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 06/29/2017] [Indexed: 12/16/2022] Open
Abstract
Frizzled (FZD) proteins are receptors for secreted WNT proteins and play a critical role in the malignant progression of various cancers. However, the role of human FZD family members in esophageal squamous cell carcinoma (ESCC) was rarely investigated. In this study, we found that the FZD7 gene was the most commonly up-regulated FZD member in ESCC cell lines compared with other FZDs. TMA studies further validated that FZD7 protein was up-regulated in 165 of 252 (65.5%) informative ESCC patients and significantly correlated with poor overall survival (P=0.001). Additionally, multivariate Cox regression analysis showed that FZD7 overexpression was an independent prognostic factor for ESCC patients. Ectopic expression of FZD7 could promote ESCC cell metastasis both in vitro and in vivo. Under WNT3A stimulation, FZD7 was able to induce the nuclear translocation of β-catenin and activate the downstream targets of WNT/β-catenin signaling, as well as promote epithelial-mesenchymal transition (EMT) potential in ESCC cells. Our study demonstrated for the first time that FZD7 contributes to the malignant progression of ESCC and represents a novel prognostic marker and a potential therapeutic target for ESCC patients.
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Affiliation(s)
- Ting-Ting Cao
- Department of Pharmacology and Cancer Research Centre, School of Medicine, Shenzhen University, Shenzhen, China
| | - Di Xiang
- Department of Pharmacology and Cancer Research Centre, School of Medicine, Shenzhen University, Shenzhen, China
| | - Bei-Lei Liu
- Department of Pharmacology and Cancer Research Centre, School of Medicine, Shenzhen University, Shenzhen, China
| | - Tu-Xiong Huang
- Department of Pharmacology and Cancer Research Centre, School of Medicine, Shenzhen University, Shenzhen, China
| | - Bin-Bin Tan
- Department of Pharmacology and Cancer Research Centre, School of Medicine, Shenzhen University, Shenzhen, China
| | - Chui-Mian Zeng
- Department of Pharmacology and Cancer Research Centre, School of Medicine, Shenzhen University, Shenzhen, China
| | - Zhong-Yuan Wang
- Department of Pharmacology and Cancer Research Centre, School of Medicine, Shenzhen University, Shenzhen, China
| | - Xiao-Yan Ming
- Department of Clinical Oncology, The University of Hong Kong Faculty of Medicine, Hong Kong, China
| | - Li-Yi Zhang
- Department of Clinical Oncology, The University of Hong Kong Faculty of Medicine, Hong Kong, China
| | - Guangyi Jin
- Department of Pharmacology and Cancer Research Centre, School of Medicine, Shenzhen University, Shenzhen, China
| | - Feng Li
- Wuhan University Shenzhen Research Institute, Shenzhen, China.,Department of Medical Genetics, School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Jian-Lin Wu
- State Key Laboratory for Quality Research in Chinese Medicines, Macau University of Science and Technology, Macau, China
| | - Xin-Yuan Guan
- Department of Clinical Oncology, The University of Hong Kong Faculty of Medicine, Hong Kong, China
| | - Desheng Lu
- Department of Pharmacology and Cancer Research Centre, School of Medicine, Shenzhen University, Shenzhen, China
| | - Li Fu
- Department of Pharmacology and Cancer Research Centre, School of Medicine, Shenzhen University, Shenzhen, China
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Mennerick S, Zeng CM, Benz A, Shen W, Izumi Y, Evers AS, Covey DF, Zorumski CF. Effects on gamma-aminobutyric acid (GABA)(A) receptors of a neuroactive steroid that negatively modulates glutamate neurotransmission and augments GABA neurotransmission. Mol Pharmacol 2001; 60:732-41. [PMID: 11562435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023] Open
Abstract
Neurosteroids positively and negatively modulate gamma-aminobutyric acid (GABA)(A) receptors and glutamate receptors, which underlie most fast inhibition and excitation in the central nervous system. We report the identification of a neuroactive steroid, (3 alpha,5 beta)-20-oxo-pregnane-3-carboxylic acid (3 alpha 5 beta PC), with unique cellular actions. 3 alpha 5 beta PC positively modulates GABA(A) receptor function and negatively modulates N-methyl-D-aspartate (NMDA) receptor function, a combination that may be of particular clinical benefit. 3 alpha 5 beta PC promotes net GABA(A) potentiation at low steroid concentrations (<10 microM) and at negative membrane potentials. At higher concentrations, the steroid also blocks GABA receptors. Because this block would presumably counteract the NMDA receptor blocking actions of 3 alpha 5 beta PC, we characterize the GABA receptor block in some detail. Agonist concentration, depolarization, and high extracellular pH increase the block. The apparent pK for both potentiation and block was 6.4 to 6.9, substantially higher than expected from carboxylated steroid in an aqueous environment. Block is not dependent on the stereochemistry of the carboxylic acid at carbon 3 and is relatively insensitive to placement of the carboxylic acid at the opposite end of the steroid (carbon 24). Potentiation is critically dependent on the stereochemistry of the carboxylic acid group at carbon 3. Consistent with the pH dependence of potentiation, effects of the amide derivative (3 alpha,5 beta)-20-oxo-pregnane-3-carboxamide, suggest that the un-ionized form of 3 alpha 5 beta PC is important for potentiation, whereas the ionized form is probably responsible for block. Further refinement of the neuroactive steroid to promote GABA potentiation and NMDA receptor block and diminish GABA receptor block may lead to a clinically useful neuroactive steroid.
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Affiliation(s)
- S Mennerick
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
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Gottschalk I, Lundqvist A, Zeng CM, Hägglund CL, Zuo SS, Brekkan E, Eaker D, Lundahl P. Conversion between two cytochalasin B-binding states of the human GLUT1 glucose transporter. Eur J Biochem 2000; 267:6875-82. [PMID: 11082199 DOI: 10.1046/j.1432-1033.2000.01788.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Two cytochalasin B-binding states of the human red blood cell facilitative glucose transporter GLUT1 were studied, one exhibiting one cytochalasin B-binding site on every second GLUT1 monomer (state 1) and the other showing one site per monomer (state 2). Quantitative affinity chromatography of cytochalasin B was performed on (a) biotinylated red blood cells, (b) cytoskeleton-depleted red blood cell membrane vesicles, and (c) GLUT1 proteoliposomes. The cells were adsorbed on streptavidin-derivatized gel beads, and the vesicles and proteoliposomes entrapped in dextran-grafted agarose gel beads. Cytochalasin B binding to free vesicles and proteoliposomes was analyzed by Hummel and Dreyer size-exclusion chromatography and ultracentrifugation. Analysis of the biotinylated cells indicated an equilibrium between the two GLUT1 states. GLUT1 in free membrane vesicles attained state 2, but was converted into state 1 on entrapment of the vesicles. Purification of GLUT1 in the presence of non-ionic detergent followed by reconstitution produced GLUT1 in state 1. This state was maintained after entrapment of the proteoliposomes. Finally, GLUT1 showed slightly higher affinity for cytochalasin B in state 1 than in state 2. In summary, the cytochalasin B-binding state of GLUT1 seemed to be affected by (a) biotinylation of the cell surface, (b) removal of the cytoskeleton at high pH and low ionic strength, (c) interaction between the dextran-grafted agarose gel matrix and the membrane vesicles, and (d) reconstitution to form proteoliposomes.
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Affiliation(s)
- I Gottschalk
- Department of Biochemistry, Biomedical Center, Uppsala University, Sweden
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7
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Pu Y, Li QF, Zeng CM, Gao J, Qi J, Luo DX, Mahankali S, Fox PT, Gao JH. Increased detectability of alpha brain glutamate/glutamine in neonatal hypoxic-ischemic encephalopathy. AJNR Am J Neuroradiol 2000; 21:203-12. [PMID: 10669252 PMCID: PMC7976324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/1999] [Accepted: 07/30/1999] [Indexed: 02/15/2023]
Abstract
BACKGROUND AND PURPOSE Proton MR spectroscopy (MRS) detectability of brain glutamate/glutamine (Glx) is increased in hypoxic-ischemic insults and is implicated in the neuronal injury and death that follows. Our aim was to correlate the proton MRS detectability of alpha-CH protons of Glx (alpha-Glx) with the Sarnat stage of neonatal hypoxic-ischemic encephalopathy (HIE). METHODS Initial and follow-up proton MRS studies at 1.9 T were performed in 28 neonates aged 1 to 7 days (seven healthy control subjects and 21 with HIE: 10 mild, nine moderate, and two severe) and in 12 neonates aged 13 to 17 days (12 with HIE: eight mild, three moderate, and one severe), respectively. Both point-resolved spectroscopy (PRESS) and stimulated-echo acquisition mode (STEAM) sequences were used. The spectral volume of interest was in the basal ganglia, thalami, and adjoining regions. The detectability of alpha-Glx was assessed by two different parameters: the detection rate of the alpha-Glx peak and the peak-area ratio of alpha-Glx to creatine and phosphocreatine. RESULTS On both the initial and follow-up PRESS studies, all the neonates with moderate and severe HIE showed an alpha-Glx peak, compared with one healthy control subject in the initial study and one neonate with mild HIE in both the studies. They also demonstrated a significantly higher peak-area ratio of alpha-Glx/(creatine and phosphocreatine) on both the initial and follow-up studies. The peak-area ratios in neonates with HIE positively correlated with the Sarnat stage of HIE on both the initial and follow-up studies. Neonates with moderate and severe HIE also showed a consistently higher alpha-Glx peak on both the initial and follow-up studies with the STEAM sequence. CONCLUSION Proton MRS detectability of alpha-Glx is increased in moderate and severe HIE and correlates with the Sarnat stage of HIE.
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Affiliation(s)
- Y Pu
- The People's Hospital of The Beijing Medical University, The People's Republic of China
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8
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Lundahl P, Zeng CM, Lagerquist Hägglund C, Gottschalk I, Greijer E. Chromatographic approaches to liposomes, proteoliposomes and biomembrane vesicles. J Chromatogr B Biomed Sci Appl 1999; 722:103-20. [PMID: 10068136 DOI: 10.1016/s0378-4347(98)00370-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Size-exclusion chromatography has been used for fractionation of liposomes, proteoliposomes and biomembrane vesicles of up to approximately 500 nm in size and for separation of these entities from smaller components. Liposome sizes, encapsulation stability, and solute affinities for membrane proteins have been determined. Counter-current distribution in aqueous two-phase systems has widened the range of applications to larger structures. Immobilized biomembrane vesicles and (proteo)liposomes provide stationary phases for chromatographic analysis of specific or nonspecific membrane-solute interactions.
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Affiliation(s)
- P Lundahl
- Department of Biochemistry, Biomedical Center, Uppsala University, Sweden
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Haneskog L, Zeng CM, Lundqvist A, Lundahl P. Biomembrane affinity chromatographic analysis of inhibitor binding to the human red cell nucleoside transporter in immobilized cells, vesicles and proteoliposomes. Biochim Biophys Acta 1998; 1371:1-4. [PMID: 9565649 DOI: 10.1016/s0005-2736(98)00008-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The affinity of the human red cell nucleoside transporter for the transport inhibitor nitrobenzylthioinosine decreases upon protein purification. The affinity was highest for the whole cells (Kd, 0.04 nM), lowered upon cytoskeleton depletion (Kd, 0.2 nM) and lowest after partial purification and reconstitution (Kd, 0.3 nM), as determined by frontal affinity chromatography.
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Affiliation(s)
- L Haneskog
- Department of Biochemistry, Biomedical Center, Uppsala University, Box 576, S-751 23 Uppsala, Sweden
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10
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Lu L, Lundqvist A, Zeng CM, Lagerquist C, Lundahl P. D-Glucose, forskolin and cytochalasin B affinities for the glucose transporter Glut1. Study of pH and reconstitution effects by biomembrane affinity chromatography. J Chromatogr A 1997; 776:81-6. [PMID: 9286080 DOI: 10.1016/s0021-9673(97)00151-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The affinities of D-glucose and the transport inhibitors, forskolin and cytochalasin B (CB), for Glut1 were studied by frontal affinity chromatography at pH 5-10 on sterically immobilized proteoliposomes with reconstituted human red cell glucose transporter Glut1. The affinity of D-glucose for Glut1 became slightly weaker as the pH was increased. The inhibitor affinities decreased and became immeasurably weak above pH 9. At pH 7.4, the dissociation constants were 44 mM for glucose, 1.8 microM for forskolin and 72 nM for CB. The affinities of these solutes for Glut1 in red cell membrane vesicles and particularly for Glut1 in red cells were higher, as shown by chromatographic analyses.
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Affiliation(s)
- L Lu
- Department of Biochemistry, Uppsala University, Sweden
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11
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Zeng CM, Zhang Y, Lu L, Brekkan E, Lundqvist A, Lundahl P. Immobilization of human red cells in gel particles for chromatographic activity studies of the glucose transporter Glut1. Biochim Biophys Acta 1997; 1325:91-8. [PMID: 9106486 DOI: 10.1016/s0005-2736(96)00247-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Chromatography on a novel stationary phase, human red cells immobilized in a gel bed, was introduced for analysis of activities of the glucose transporter Glut1 in the cell membrane. A gel containing positively charged ligands was synthesized from derivatized acrylamide monomers. Red cells were immobilized in gel particles which were packed into a column tube for chromatographic analyses over periods of 10-15 days. D-Glucose was separated from L-glucose on a 1.1-ml bed with a retention volume difference of 0.23 ml, approximately equal to the total inner volume of immobilized intact cells and of ghosts probably formed from lysed cells during the immobilization. The separation was suppressed by the glucose-transport inhibitor cytochalasin B. The interactions between D-glucose, the transport inhibitor forskolin and Glut1 were analyzed by quantitative frontal affinity chromatography. The dissociation constants at room temperature were 6.8 mM for D-glucose binding and 1.8 microM for glucose-displaceable binding of forskolin, in good agreement with published values. The results suggest that chromatography on immobilized cells is a potentially useful tool for studies on cellular membrane functions.
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Affiliation(s)
- C M Zeng
- Department of Biochemistry, Uppsala University, Sweden
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12
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Zhang Y, Zeng CM, Li YM, Hjertén S, Lundahl P. Immobilized liposome chromatography of drugs on capillary continuous beds for model analysis of drug-membrane interactions. J Chromatogr A 1996; 749:13-8. [PMID: 8921592 DOI: 10.1016/0021-9673(96)00432-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Liposomes were immobilized in capillary continuous beds with covalently linked C4 or C8 alkyl ligands for chromatographic analysis of drug interaction with phospholipid bilayers, as reflected by drug retention volumes and calculated differences in interaction free energies. This procedure is a high-resolution micro-scale version of immobilized liposome chromatography for prediction of diffusion of drugs across biological membranes. The logarithm of the specific capacity factors of several structurally unrelated drugs showed a linear correlation with the logarithm of known apparent drug permeabilities through Caco-2 epithelial cell monolayers. The latter values are used for prediction of absorption of orally administered drug doses.
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Affiliation(s)
- Y Zhang
- Department of Biochemistry, Uppsala University, Sweden
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13
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Abstract
Continuous beds have been used as matrices for cation- and anion-exchange chromatography of proteins on columns with an i.d. in the range of 0.005-0.015 mm. On-tube uv detection is not feasible at low protein concentrations with these narrow-bore columns. Therefore, a more sensitive detection system has been developed based on blotting technique: as the protein zones leave the microcolumn chromatographically they become adsorbed onto a rotating polyvinylidene difluoride blotting membrane. The protein spots can then be visualized by means of Coomassie brilliant blue, immunomethods, and other standard techniques. By using an immunomethod 0.015 ng of human transferrin can easily be detected. The blotting membrane can be washed with water without loss of adsorbed protein. This is an attractive feature because the presence of salts, etc., diminishes the accuracy in the determination of molecular weights of proteins by mass spectrometry. The microcolumns are easy to prepare. A solution of appropriate monomers is sucked into a piece of fused silica tubing. The rod formed upon polymerization contains channels through which the eluent can pass. No supporting frit is required because the polymer rod is anchored by covalent bonds to the tubing wall.
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Affiliation(s)
- J L Liao
- Department of Biochemistry, Uppsala University, Sweden
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14
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Zeng CM, Ishibashi M, Kobayashi J. Biemnasterol, a new cytotoxic sterol with the rare 22,25-diene side chain, isolated from the marine sponge Biemna sp. J Nat Prod 1993; 56:2016-2018. [PMID: 8289069 DOI: 10.1021/np50101a027] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Biemnasterol [2], a new sterol with a 22,25-diene side chain possessing cytotoxic activity, has been isolated from the Okinawan marine sponge Biemna sp. and the structure elucidated on the basis of spectroscopic data and chemical means.
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Affiliation(s)
- C M Zeng
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
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Kobayashi J, Zeng CM, Ishibashi M, Sasaki T. Luffariolides F and G, new manoalide derivatives from the Okinawan marine sponge Luffariella sp. J Nat Prod 1993; 56:436-439. [PMID: 8482949 DOI: 10.1021/np50093a020] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Affiliation(s)
- J Kobayashi
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
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