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Luo Y, Zeng L, Xie XQ, Wang F, Liu YZ, Kang JB, Li XF, Wu DB, Qu BL. H3K27M mutant diffuse midline glioma: a case report. Eur Rev Med Pharmacol Sci 2021; 24:2579-2584. [PMID: 32196609 DOI: 10.26355/eurrev_202003_20527] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
OBJECTIVE Diffuse midline glioma with H3K27M mutation is a new tumor type of WHO central nervous system tumor classification. It often occurs in the midline structure and usually has a poor prognosis. CASE REPORT A 38-year-old male patient presented with 2 years history of right limb with facial numbness, tumors in the left thalamic region and lateral ventricle was detected by imaging. The patient underwent the first surgery. RESULTS The pathological examination results: Glioblastoma. He recovered well after surgery and received a total of 30 times of radiotherapy and temozolomide for one year. Fourteen months later, tumours were observed in the left thalamic region and left parieto-occipital lobe, the patient underwent the second operation. Immunohistochemistry showed: H3K27M(+). He experienced limitation of right limb movement after surgery and started taking oral apatinib 250 mg qd. After one-year, multiple tumors were found in the left brainstem, bilateral ventricles, bilateral basal ganglia, etc. The patient was given radiotherapy 7 times and then took apatinib 250 mg qd. Now the patient is still alive. CONCLUSIONS H3K27M mutant diffuse midline glioma is characterized by diffuse infiltrative growth. Its pathological classification is diverse, imaging features lack specificity, and prognostic factors are complex. Traditional radiochemotherapy has limited effects, molecular targeted therapy, especially intervention of epigenetic regulation is being explored.
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Affiliation(s)
- Y Luo
- Department of Medical Oncology, Cancer Center, West China Hospital, West China Medical School, Sichuan University, Sichuan, P.R. China.
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Wang SC, Wu J, Xie XQ, Liu XL, Luo Y, Wang F, Li ZP, Qu BL, Kang JB, Wu DB, Li WM, Wang RY. Comparison of IMRT and VMAT radiotherapy planning for Graves' ophthalmopathy based on dosimetric parameters analysis. Eur Rev Med Pharmacol Sci 2020; 24:3898-3906. [PMID: 32329865 DOI: 10.26355/eurrev_202004_20856] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
OBJECTIVE To compare volumetric modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT) for the treatment of Graves' ophthalmopathy (GO) based on the dosimetric data. PATIENTS AND METHODS 19 patients diagnosed with GO were recruited in this study. For each patient, a dual-partial-arc VMAT plans and a 7-fixed-field IMRT plans were replanned. Dosimetric parameters of the targets and organs at risk (OARs) originated from the two kinds of plans were compared and analyzed. RESULTS Homogeneity index (HI) was superior in IMRT plans compared with VMAT (p=0.0014) but there was no significant statistical difference in conformity index (CI) between them (p=0.0673). IMRT plans revealed advantage in the OARs protection especially for the left and right lenses, optic nerves and eyeballs (p<0.05). CONCLUSIONS VMAT and IMRT are both feasible techniques in radiotherapy in GO from the perspective of dosimetric parameters. Homogeneity and OAR protection were slightly superior in IMRT plans compared with VMAT plans.
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Affiliation(s)
- S-C Wang
- Department of Radiation Oncology, Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu, P.R. China.
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van den Oever LB, Vonder M, van Assen M, van Ooijen PMA, de Bock GH, Xie XQ, Vliegenthart R. Application of artificial intelligence in cardiac CT: From basics to clinical practice. Eur J Radiol 2020; 128:108969. [PMID: 32361380 DOI: 10.1016/j.ejrad.2020.108969] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 01/30/2020] [Accepted: 03/11/2020] [Indexed: 12/18/2022]
Abstract
Research into the possibilities of AI in cardiac CT has been growing rapidly in the last decade. With the rise of publicly available databases and AI algorithms, many researchers and clinicians have started investigations into the use of AI in the clinical workflow. This review is a comprehensive overview on the types of tasks and applications in which AI can aid the clinician in cardiac CT, and can be used as a primer for medical researchers starting in the field of AI. The applications of AI algorithms are explained and recent examples in cardiac CT of these algorithms are further elaborated on. The critical factors for implementation in the future are discussed.
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Affiliation(s)
- L B van den Oever
- University of Groningen, University Medical Center Groningen, Department of Radiation Oncology, the Netherlands
| | - M Vonder
- University of Groningen, University Medical Center Groningen, Department of Epidemiology, the Netherlands
| | - M van Assen
- University of Groningen, University Medical Center Groningen, Faculty of Medicine, Groningen, the Netherlands; Divisions of Cardiothoracic Imaging, Nuclear Medicine and Molecular Imaging, Department of Radiology and Imaging Sciences, Emory University Hospital, Atlanta, GA, USA
| | - P M A van Ooijen
- University of Groningen, University Medical Center Groningen, Department of Radiation Oncology, the Netherlands
| | - G H de Bock
- University of Groningen, University Medical Center Groningen, Department of Epidemiology, the Netherlands
| | - X Q Xie
- Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Department of Radiology, Shanghai, The People's Republic of China
| | - R Vliegenthart
- University of Groningen, University Medical Center Groningen, Department of Radiology, the Netherlands.
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Xie XQ, Luo Y, Ma XL, Li SS, Liu L, Zhang H, Li P, Wang F. Clinical significance of circulating tumor cells and their expression of cyclooxygenase-2 in patients with nasopharyngeal carcinoma. Eur Rev Med Pharmacol Sci 2019; 23:6951-6961. [PMID: 31486495 DOI: 10.26355/eurrev_201908_18735] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVE To explore the expression of circulating tumor cells (CTCs) and cyclooxygenase-2 (COX-2) in CTCs and to assess their association with clinical parameters and treatment. PATIENTS AND METHODS Peripheral blood samples from 50 patients with nasopharyngeal carcinoma (NPC) were included. We applied advanced CanPatrolTM CTC enrichment technique and in situ hybridization assay to isolate, identify, and classify CTCs and COX-2 in CTCs. Epstein-Barr virus DNA was detected by Real Time-quantitative PCR (RT-qPCR). RESULTS No CTCs were identified in ten healthy volunteers (100%). Of the total patients, 48 (96%) had positive CTCs counts and 36 (72%) had positive mesenchymal CTCs counts before treatment. CTCs cells were highly expressed in different NPC stages, and the positive ratio of mesenchymal CTCs in stage IV was higher than that in other stages. The proportion of mesenchymal cells was higher expressed in metastasis patients. The expression of COX-2 was different in different types of CTCs. The positivity of COX-2 in CTCs was higher in stage IV patients than that in stage II and stage III patients. Decreased mesenchymal CTCs and that express COX-2 indicated a favorable curative effect in NPC patients. The positivity of mesenchymal CTCs and COX-2 was higher in EBV DNA positive patients compared with EBV DNA negative patients (p<0.05). Meanwhile, the mean number of CTCs, mesenchymal CTCs, CTCs that express COX-2, hybrid CTCs that express COX-2 and mesenchymal CTCs that express COX-2 was significantly higher in the EBV DNA positive patients than negative patients before treatment (p<0.05). CONCLUSIONS CTCs and their expression of COX-2 were correlated with NPC clinical characteristics, and have a relation with Epstein-Barr virus DNA. Decreased mesenchymal CTCs and that express COX-2 indicated a favorable curative effect in NPC patients.
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Affiliation(s)
- X-Q Xie
- Department of Medical Oncology, Cancer Center, the State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan Province, China.
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Zeng L, Xie XQ, Li CH, Shi HS, Wang F. Clinical study of the radiotherapy with EDGE accelerator in the treatment of the moderate and severe thyroid associated ophthalmopathy. Eur Rev Med Pharmacol Sci 2019; 23:3471-3477. [PMID: 31081102 DOI: 10.26355/eurrev_201904_17712] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVE To explore the short-term efficacy, acute complications and response factors after the radiotherapy with EDGE accelerator in patients with moderate and severe thyroid-associated ophthalmopathy (TAO). PATIENTS AND METHODS A total of 68 patients with moderate and severe TAO who received the radiotherapy with EDGE accelerator between August 1st, 2017 and May 1st, 2011 were enrolled in the present study. The clinical data were collected, and the efficacy and acute complications were followed up, and the response factors were analyzed. RESULTS Sixty-eight patients (136 eyes) were followed up for 6 months after radiotherapy. The total score after radiotherapy was significantly lower compared to that before the therapy (p<0.05), and the effective rate was 75.74%. After the radiotherapy, the patient's exophthalmia, soft tissue involvement, eye external muscle involvement, corneal involvement, decreased vision and diplopia, tearing and eyelid pain have improved. Acute complications included increased local inflammation, hair loss, pigmentation and xerophthalmias. In addition, multivariate logistic regression analysis demonstrated that thyroid hormone level was the independent factor for the response to the radiotherapy. CONCLUSIONS For patients with moderate and severe TAO, radiotherapy with EDGE accelerator is a safe and effective treatment option. Maintaining normal thyroid hormone level can improve the effective rate of radiotherapy.
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Affiliation(s)
- L Zeng
- Department of Medical Oncology, Cancer Center, the State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan Province, China.
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Wei ZH, Xie XQ, Liu F, Wang P, Wang J, Gao YL, Su JT, Du J, Liu QP, Deng XH. [Analysis on causes of death of residents in Beijing, 1965-1974]. Zhonghua Liu Xing Bing Xue Za Zhi 2017; 37:977-80. [PMID: 27453108 DOI: 10.3760/cma.j.issn.0254-6450.2016.07.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVE To fill up the absence of data on causes of death of urban residents in Beijing during 1965-1974 and provide evidence for the similar study in other areas. METHODS All possible sources for death data during 1965-1974 were identified through expert consultations and record search. Stratified sampling was conducted to collect the death data of urban residents during this period in Beijing. The mortality rate, death cause constituent and rank of death causes were used in this descriptive analysis. RESULTS A total of 11 668 records of deaths from 1965 to 1974 were collected from 10 local police stations in urban area of Beijing. The top 10 death causes in the urban residents were heart disease, tumor, cerebrovascular disease, accidental injury, respiratory system disease, digestive system disease, communicable disease and parasitic disease, nervous system disease, urogenital and reproductive system disease, endocrine and nutrition metabolic diseases. The deaths caused by these diseases accounted for 84.19% of the total deaths. Accidental injury accounted for 13.22% of the total deaths, which was significantly higher than that in either 1964 or 1975, two years before and after this period(P<0.01). Suicide accounted for 54.47% of the total accidental injury deaths. For men, accidental injury was the leading death cause, followed by cancer and heart disease; for women, heart disease, cancer and cerebrovascular disease were the top three death causes. CONCLUSION The major death cause in urban residents changed from infectious diseases to chronic and non-communicable diseases during 1965-1974. A remarkable high proportion of deaths caused by accidental injury was due to the historical background during that period in Beijing, China.
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Affiliation(s)
- Z H Wei
- Department of Statistics and Information, Beijing Municipal Center for Diseases Control and Prevention, Beijing 100013, China; School of Public Health, Capital Medical University School, Beijing 100069, China
| | - X Q Xie
- Beijing Municipal Health and Family Planning Commission, Beijing 100053, China
| | - F Liu
- School of Public Health, Capital Medical University School, Beijing 100069, China
| | - P Wang
- Department of Statistics and Information, Beijing Municipal Center for Diseases Control and Prevention, Beijing 100013, China
| | - J Wang
- Department of Statistics and Information, Beijing Municipal Center for Diseases Control and Prevention, Beijing 100013, China
| | - Y L Gao
- Department of Statistics and Information, Beijing Municipal Center for Diseases Control and Prevention, Beijing 100013, China
| | - J T Su
- Department of Statistics and Information, Beijing Municipal Center for Diseases Control and Prevention, Beijing 100013, China
| | - J Du
- Department of Statistics and Information, Beijing Municipal Center for Diseases Control and Prevention, Beijing 100013, China
| | - Q P Liu
- Department of Statistics and Information, Beijing Municipal Center for Diseases Control and Prevention, Beijing 100013, China
| | - X H Deng
- Beijing Municipal Health and Family Planning Commission, Beijing 100053, China
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Zhu YB, Xie XQ, Li ZY, Bai H, Dong L, Dong ZP, Dong JG. Bioinformatic analysis of the nucleotide binding site-encoding disease-resistance genes in foxtail millet (Setaria italica (L.) Beauv.). Genet Mol Res 2014; 13:6602-9. [PMID: 25177941 DOI: 10.4238/2014.august.28.5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The nucleotide-binding site (NBS) disease-resistance genes are the largest category of plant disease-resistance gene analogs. The complete set of disease-resistant candidate genes, which encode the NBS sequence, was filtered in the genomes of two varieties of foxtail millet (Yugu1 and 'Zhang gu'). This study investigated a number of characteristics of the putative NBS genes, such as structural diversity and phylogenetic relationships. A total of 269 and 281 NBS-coding sequences were identified in Yugu1 and 'Zhang gu', respectively. When the two databases were compared, 72 genes were found to be identical and 164 genes showed more than 90% similarity. Physical positioning and gene family analysis of the NBS disease-resistance genes in the genome revealed that the number of genes on each chromosome was similar in both varieties. The eighth chromosome contained the largest number of genes and the ninth chromosome contained the lowest number of genes. Exactly 34 gene clusters containing the 161 genes were found in the Yugu1 genome, with each cluster containing 4.7 genes on average. In comparison, the 'Zhang gu' genome possessed 28 gene clusters, which had 151 genes, with an average of 5.4 genes in each cluster. The largest gene cluster, located on the eighth chromosome, contained 12 genes in the Yugu1 database, whereas it contained 16 genes in the 'Zhang gu' database. The classification results showed that the CC-NBS-LRR gene made up the largest part of each chromosome in the two databases. Two TIR-NBS genes were also found in the Yugu1 genome.
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Affiliation(s)
- Y B Zhu
- Molecular Plant Pathology Laboratory, Agricultural University of Hebei, Baoding, China
| | - X Q Xie
- School of Life Science, Peking University, Beijing, China
| | - Z Y Li
- Millet Institute, Hebei Academy of Agricultural and Forestry Sciences, Shijiazhuang, China
| | - H Bai
- Millet Institute, Hebei Academy of Agricultural and Forestry Sciences, Shijiazhuang, China
| | - L Dong
- Millet Institute, Hebei Academy of Agricultural and Forestry Sciences, Shijiazhuang, China
| | - Z P Dong
- Millet Institute, Hebei Academy of Agricultural and Forestry Sciences, Shijiazhuang, China
| | - J G Dong
- Molecular Plant Pathology Laboratory, Agricultural University of Hebei, Baoding, China
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Chen JZ, Myint KZ, Xie XQ. New QSAR prediction models derived from GPCR CB2-antagonistic triaryl bis-sulfone analogues by a combined molecular morphological and pharmacophoric approach. SAR QSAR Environ Res 2011; 22:525-544. [PMID: 21714749 DOI: 10.1080/1062936x.2011.569948] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In order to build quantitative structure-activity relationship (QSAR) models for virtual screening of novel cannabinoid CB2 ligands and hit ranking selections, a new QSAR algorithm has been developed for the cannabinoid ligands, triaryl bis-sulfones, using a combined molecular morphological and pharmacophoric search approach. Both pharmacophore features and shape complementarity were considered using a number of molecular descriptors, including Surflex-Sim similarity and Unity Query fit, in addition to other molecular properties such as molecular weight, ClogP, molecular volume, molecular area, molecular polar volume, molecular polar surface area and dipole moment. Subsequently, partial least squares regression analyses were carried out to derive QSAR models linking bioactivity and the descriptors mentioned, using a training set of 25 triaryl bis-sulfones. Good prediction capability was confirmed for the best QSAR model by evaluation against a test set of a further 20 triaryl bis-sulfones. The pharmacophore and molecular shape-based QSAR scoring function now established can be used to predict the biological properties of virtual hits or untested compounds obtained from ligand-based virtual screenings.
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Affiliation(s)
- J-Z Chen
- Department of Pharmaceutical Sciences, University of Pittsburgh, PA, USA
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Abstract
Quantitative structure-activity relationship (QSAR) studies are useful computational tools often used in drug discovery research and in many scientific disciplines. In this study, a robust fragment-similarity-based QSAR (FS-QSAR) algorithm was developed to correlate structures with biological activities by integrating fragment-based drug design concept and a multiple linear regression method. Similarity between any pair of training and testing fragments was determined by calculating the difference of lowest or highest eigenvalues of the chemistry space BCUT matrices of corresponding fragments. In addition to the BCUT-similarity function, molecular fingerprint Tanimoto coefficient (Tc) similarity function was also used as an alternative for comparison. For validation studies, the FS-QSAR algorithm was applied to several case studies, including a dataset of COX2 inhibitors and a dataset of cannabinoid CB2 triaryl bis-sulfone antagonist analogues, to build predictive models achieving average coefficient of determination (r(2)) of 0.62 and 0.68, respectively. The developed FS-QSAR method is proved to give more accurate predictions than the traditional and one-nearest-neighbour QSAR methods and can be a useful tool in the fragment-based drug discovery for ligand activity prediction.
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Affiliation(s)
- K Z Myint
- Department of Computational Biology, School of Medicine, University of Pittsburgh, Pittsburgh, USA
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Abstract
The expression of membrane proteins has been the bottleneck for their structural studies. Recently, we developed a method to obtain milligram quantities of isotope-labeled seven transmembrane G-protein coupled cannabinoid (CB) receptor fragment in E. coli. In order to verify this method and confirm the recombinant isotope-labeled CB2 fragment, 3D hetero-nuclear NMR techniques were used to analyze the structure of the fragment CB2(180-233) in DMSO-d6 solvent. The sequential assignments of TM5 and intra-cellular loop 3 were accomplished, which confirmed the experimental protocols of isotope-labeled recombinant protein expression, fusion protein cleavage, and membrane protein purification. The obtained structure also showed alpha-helix in the TM5 region, but it was interrupted by a disordered region (Gly204_ILe206). These results further revealed that our established approach is a promising method to express recombinant membrane proteins for their structural studies.
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Affiliation(s)
- J Zhao
- Department of Pharmaceutical and Pharmacological Sciences, College of Pharmacy, University of Houston, TX 77204-5037, USA
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Zheng H, Zhao J, Wang S, Lin CM, Chen T, Jones DH, Ma C, Opella S, Xie XQ. Biosynthesis and purification of a hydrophobic peptide from transmembrane domains of G-protein-coupled CB2 receptor. ACTA ACUST UNITED AC 2005; 65:450-8. [PMID: 15813893 DOI: 10.1111/j.1399-3011.2005.00239.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
A major challenge for the structural study of the seven-transmembrane G-protein-coupled receptors is to obtain a sufficient amount of purified protein at the milligram level, which is required for either nuclear magnetic resonance (NMR) spectroscopy or X-ray crystallography. In order to develop a high-yield and cost-effective method, and also to obtain preliminary structural information for the computer modeling of the three-dimensional receptor structural model, a highly hydrophobic peptide from human cannabinoid subtype 2 receptor CB2(65-101), was chosen to develop high-yield membrane protein expression and purification methods. The peptide included the second transmembrane helix with the associated loop regions of the CB2 receptor. It was over-expressed in Escherichia coli, with a modified TrpDelta LE1413 (TrpLE) leading fusion sequence and a nine-histidine tag, and was then separated and purified from the tag in a preparative scale. An experimental protocol for the chemical cleavage of membrane protein fragment was developed using cyanogen bromide to remove the TrpLE tag from the hydrophobic fusion protein. In addition, protein uniformly labeled with isotopic 15N was obtained by expression in 15N-enriched minimum media. The developed and optimized preparation scheme of expression, cleavage, and purification provided a sufficient amount of peptide for NMR structure analysis and other biophysical studies that will be reported elsewhere. The process of fusion protein cleavage following purification was monitored by high-performance liquid chromatography (HPLC) and mass spectrometry (MS), and the final sample was validated by MS and circular dichroism experiments.
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Affiliation(s)
- H Zheng
- Department of Pharmaceutical & Pharmacological Sciences, College of Pharmacy, University of Houston, Houston, TX 77204-5037, USA
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Choi G, Landin J, Xie XQ. The cytoplasmic helix of cannabinoid receptor CB2, a conformational study by circular dichroism and (1)H NMR spectroscopy in aqueous and membrane-like environments. J Pept Res 2002; 60:169-77. [PMID: 12213126 DOI: 10.1034/j.1399-3011.2002.21012.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The cytoplasmic helix domain (fourth cytoplasmic loop, helix 8) of numerous G protein-coupled receptors (GPCRs) such as rhodopsin and the beta-adrenergic receptor exhibit unique structural and functional characteristics. Computer models also predict this structure for the cannabinoid CB2 receptor, another member of the GPCR superfamily. In our study, a peptide corresponding to helix 8 of the CB2 receptor was synthesized chemically and its secondary structure determined by circular dichroism (CD) and (1)H NMR spectroscopy. NMR and CD revealed an alpha-helical structure in this region in both dodecylphosphocholine micelles and dimethylsulfoxide, in contrast to a random coil configuration found in aqueous solvent. This finding is in good agreement with other previous GPCR structural studies including X-ray crystallography. By combining our finding with other studies, we further hypothesize that the amphipathic nature of helix 8 can play a significant role in the function and regulation of CB receptors as well as other GPCRs in general.
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Affiliation(s)
- G Choi
- Institute of Material Science, University of Connecticut, Storrs, USA
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Abstract
The lambda5 gene is expressed exclusively in precursor (pre-) B cells where its gene product, as part of the pre-B cell receptor, is crucial for the proliferation of these cells. Several DNA regions regulate the activity and expression pattern of the lambda5 gene. Amongst these is an enhancer, B(lambda5), located 5' of the gene. Here we analyze the lambda5 enhancer core, b(lambda5), which in earlier experiments was demonstrated to retain 50% of the enhancer activity, and show that this activity is restricted to pre-B cells. We identify a DNA element within b(lambda5), PEBP2(lambda5), which is essential for enhancer activity: mutation within this site dramatically reduces core enhancer activity in pre-B cells. The PEBP2(lambda5) site binds bacterially produced polyoma enhancer binding proteins (PEBP) (Runx/AML/CBFA). Furthermore, PEBP2 proteins present in nuclear extracts from murine pre-B cells bind to the PEBP2(lambda5) element. PEBP2 proteins in mature B cells also bind to the PEBP2(lambda5 )element, implying that if PEBP2 proteins are responsible for the stage-specific expression, they have to be non-activating or inhibiting in mature B cells. We also demonstrate that a described partner of PEBP2, c-myb, binds to a sequence termed myb(lambda5) located just upstream of the PEBP2(lambda5) site in the core enhancer. The myb(lambda5) element is also crucial for enhancer activity, since mutating the myb site reduces core enhancer activity to the same extent as mutating the PEBP2 site. Earlier reports have shown that c-myb is expressed at high levels in pre-B cell lines whereas its expression is down-regulated in more mature B cell lines. Thus, c-myb may be involved in determining the stage-specific expression of the lambda5 gene.
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Affiliation(s)
- A Mårtensson
- Department of Cell- and Molecular Biology, Lund University, Lund, Sweden
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Goutopoulos A, Fan P, Khanolkar AD, Xie XQ, Lin S, Makriyannis A. Stereochemical selectivity of methanandamides for the CB1 and CB2 cannabinoid receptors and their metabolic stability. Bioorg Med Chem 2001; 9:1673-84. [PMID: 11425567 DOI: 10.1016/s0968-0896(01)00088-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Several chiral, analogues of the endogenous cannabinoid receptor ligand, arachidonylethanolamide (anandamide), methylated at the 2,1' and 2' positions using asymmetric synthesis were evaluated in order to study (a) stereoselectivity of binding to CB1 and CB2 cannabinoid receptors; and (b) metabolic stability with regard to anandamide amidase. Enantiomerically pure 2-methyl arachidonic acids were synthesized through diastereoselective methylation of the respective chiral 2-oxazolidinone enolate derivatives and CB1 and CB2 receptor affinities of the resulting chiral anandamides were evaluated using a standard receptor binding assay. Introduction of a single 2-methyl group increased affinity for CB1, led to limited enantioselectivity and only modestly improved metabolic stability. However, a high degree of enantio- and diastereoselectivity was observed for the 2,1'-dimethyl analogues. (R)-N-(1-methyl-2-hydroxyethyl)-2-(R)-methyl-arachidonamide (4) exhibited the highest CB1 receptor affinity in this series with a K(i) of 7.42 nM, an at least 10-fold improvement on anandamide (K(i)=78.2 nM). The introduction of two methyl groups at the 2-position of anandamide led to no change in affinity for CB1 but somewhat enhanced metabolic stability. Conversely, chiral headgroup methylation in the 2-gem-dimethyl series led to chiral analogues possessing a wide range of CB1 affinities. Of these the (S)-2,2,2'-trimethyl analogue (12) had the highest affinity for CB1 almost equal to that of anandamide. In agreement with our previous anandamide structure-activity relationship work, the analogues in this study showed high selectivity for the CB1 receptor over CB2. The results are evaluated in terms of stereochemical factors affecting the ligand's affinity for CB1 using receptor-essential volume mapping as an aid. Based on the results, a partial CB1 receptor site model is proposed, that bears two hydrophobic pockets capable of accommodating 1'- and 2-methyl groups
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Affiliation(s)
- A Goutopoulos
- Department of Pharmaceutical Sciences, and Center for Drug Discovery, University of Connecticut, Storrs, CT 06269, USA
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Bäckström S, Huang SH, Wolf-Watz M, Xie XQ, Härd T, Grundström T, Sauer UH. Crystallization and preliminary studies of the DNA-binding runt domain of AML1. Acta Crystallogr D Biol Crystallogr 2001; 57:269-71. [PMID: 11173476 DOI: 10.1107/s0907444900015791] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2000] [Accepted: 10/31/2000] [Indexed: 11/10/2022]
Abstract
The acute myeloid leukaemia 1 (AML1) protein belongs to the Runx family of transcription factors and is crucial for haematopoietic development. The genes encoding Runx1 and its associated factor CBF beta are the most frequent targets for chromosomal rearrangements in acute human leukaemias. In addition, point mutations of Runx1 in acute leukaemias and in the familial platelet disorder FPD/AML cluster within the evolutionary conserved runt domain that binds both DNA and CBF beta. Here, the crystallization of the Runx1 runt domain is reported. Crystals belong to space groups C2 and R32 and diffract to 1.7 and 2.0 A resolution, respectively.
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Affiliation(s)
- S Bäckström
- Umeå Center for Molecular Pathogenesis, UCMP, Umeå University, SE-901 87, Umeå, Sweden
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Pardali E, Xie XQ, Tsapogas P, Itoh S, Arvanitidis K, Heldin CH, ten Dijke P, Grundström T, Sideras P. Smad and AML proteins synergistically confer transforming growth factor beta1 responsiveness to human germ-line IgA genes. J Biol Chem 2000; 275:3552-60. [PMID: 10652350 DOI: 10.1074/jbc.275.5.3552] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.2] [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: 01/30/2023] Open
Abstract
Transcription of germ-line immunoglobulin heavy chain genes conditions them to participate in isotype switch recombination. Transforming growth factor-beta1 (TGF-beta1) stimulates promoter elements located upstream of the IgA1 and IgA2 switch regions, designated Ialpha1 and Ialpha2, and contributes to the development of IgA responses. We demonstrate that intracellular Smad proteins mediate activation of the Ialpha1 promoter by TGF-beta. TGF-beta type 1 receptor (ALK-5), activin type IB receptor (ALK-4), and the "orphan" ALK-7 trans-activate the Ialpha1 promoter, thus raising the possibility that other members of the TGF-beta superfamily can also modulate IgA synthesis. Smads physically interact with the AML family of transcription factors and cooperate with them to activate the Ialpha1 promoter. The Ialpha1 element provides a canapé of interspersed high and low affinity sites for Smad and AML factors, some of which are indispensable for TGF-beta responsiveness. While AML.Smad complexes are formed in the cytoplasm of DG75 and K562 cells constitutively, only after TGF-beta receptor activation, novel Smad3.Smad4.AML complexes are detected in nuclear extracts by EMSA with Ialpha1 promoter-derived probes. Considering the wide range of biological phenomena that AMLs and Smads regulate, the physical/functional interplay between them has implications that extend beyond the regulation of class switching to IgA.
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Affiliation(s)
- E Pardali
- Division of Tumor Biology, Department of Cell and Molecular Biology, Umeâ University, S-901 87 Umeâ, Sweden
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17
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Xie XQ, Han XW, Chen JZ, Eissenstat M, Makriyannis A. High-resolution NMR and computer modeling studies of the cannabimimetic aminoalkylindole prototype WIN-55212-2. J Med Chem 1999; 42:4021-7. [PMID: 10514272 DOI: 10.1021/jm980592k] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Aminoalkylindoles (AAIs), although structurally dissimilar from the classical cannabinoids (CCs), are known to be capable of binding to cannabinoid receptors and of evoking cannabimimetic responses. However, their mode of binding remains unknown. In this communication, we have carried out further studies on the AAI prototype (R)-[2, 3-dihydro-5-methyl-3-[(4-morpholinyl)methyl]pyrrolo[1,2,3-de]-1, 4-benzoxazin-6-yl](1-naphthalenyl)methanone (WIN-55212-2, 1) by the combined use of high-resolution 2D NMR and computer modeling. Our results suggest that the minimum energy conformations of the molecule 1 have distinct pharmacophoric features: (i) The naphthyl ring is oriented off the plane of the benzoxazine ring by approximately 59 degrees with the carbonyl C=O group pointing toward the C2-CH(3) group. (ii) At the C10-position the axial morpholinomethyl conformation is preferred over the equatorial in order to relieve a steric interaction with the C2-methyl group. The preferred conformer as defined by the three key pharmacophores, naphthyl, morpholino, and 3-keto groups, shows that the morpholinyl ring of the molecule 1 deviates from the plane of the benzoxazine ring by about 32 degrees and orients in the left molecular quadrant. This model supports the hypothesis that a certain deviation of the morpholino group from the plane of the indole ring in compound 1 is essential for cannabimimetic activity. We postulate that such an alignment by the respective pharmacophores allows them to interact optimally with the receptor. The results should help us to better understand the pharmacophoric requirements of the AAIs and serve as a basis for future SAR studies and drug design.
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Affiliation(s)
- X Q Xie
- Institute of Materials Science, Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs, Connecticut 06269, USA.
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18
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Piomelli D, Beltramo M, Glasnapp S, Lin SY, Goutopoulos A, Xie XQ, Makriyannis A. Structural determinants for recognition and translocation by the anandamide transporter. Proc Natl Acad Sci U S A 1999; 96:5802-7. [PMID: 10318965 PMCID: PMC21941 DOI: 10.1073/pnas.96.10.5802] [Citation(s) in RCA: 204] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The biological actions of anandamide (arachidonylethanolamide), an endogenous cannabinoid lipid, are terminated by a two-step inactivation process consisting of carrier-mediated uptake and intracellular hydrolysis. Anandamide uptake in neurons and astrocytes is mediated by a high-affinity, Na+-independent transporter that is selectively inhibited by N-(4-hydroxyphenyl)-arachidonamide (AM404). In the present study, we examined the structural determinants governing recognition and translocation of substrates by the anandamide transporter constitutively expressed in a human astrocytoma cell line. Competition experiments with a select group of analogs suggest that substrate recognition by the transporter is favored by a polar nonionizable head group of defined stereochemical configuration containing a hydroxyl moiety at its distal end. The secondary carboxamide group interacts favorably with the transporter, but may be replaced with either a tertiary amide or an ester, suggesting that it may serve as hydrogen acceptor. Thus, 2-arachidonylglycerol, a putative endogenous cannabinoid ester, also may serve as a substrate for the transporter. Substrate recognition requires the presence of at least one cis double bond situated at the middle of the fatty acid carbon chain, indicating a preference for ligands whose hydrophobic tail can adopt a bent U-shaped conformation. On the other hand, uptake experiments with radioactively labeled substrates show that no fewer than four cis nonconjugated double bonds are required for optimal translocation across the cell membrane, suggesting that substrates are transported in a folded hairpin conformation. These results outline the general structural requisites for anandamide transport and may assist in the development of selective inhibitors with potential clinical applications.
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Affiliation(s)
- D Piomelli
- The Neurosciences Institute, San Diego, CA 92121, USA.
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19
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Abstract
The Runt domain is responsible for specific DNA and protein-protein interactions in a family of transcription factors which includes human AML1. Structural data on the Runt domain has not yet become available, possibly due to solubility and stability problems with expressed protein fragments. Here we describe the optimization and characterization of a 140-residue fragment, containing the Runt domain of AML1, which is suitable for structural studies. The fragment of AML1 including amino acids 46-185 [AML1 Dm(46-185)] contains a double cysteine-->serine mutation which does not affect Runt domain structure or DNA-binding affinity. Purified AML1 Dm(46-185) is soluble and optimally stable in a buffer containing 200 mm MgSO4 and 20 mm sodium phosphate at pH 6.0. Nuclear magnetic resonance and circular dichroism spectroscopy indicate that the Runt domain contains beta-sheet, but little or no alpha-helical secondary structure elements. The 45 N-terminal residues of AML1 are unstructured and removal of the N-terminal enhances sequence-specific DNA binding. The NMR spectrum of AML1 Dm(46-185) displays a favorable chemical shift dispersion and resolved NOE connectivities are readily identified, suggesting that a structure determination of this Runt domain fragment is feasible. A titration of 15N-labelled AML1 Dm(46-185) with a 14-bp cognate DNA duplex results in changes in the 15N NMR heteronuclear single quantum coherence spectrum which indicate the formation of a specific complex and structural changes in the Runt domain upon DNA binding.
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Affiliation(s)
- M Wolf-Watz
- Department of Biotechnology, Royal Institute of Technology, Stockholm, Sweden
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20
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Abstract
The immunoglobulin heavy chain (IgH) class switch recombination of B lymphocytes preferentially targets unrearranged IgH genes that have already been rendered transcriptionally active. Transcription of the germ-line IgH genes is controlled by intervening (I) regions upstream of their switch regions. The I alpha1 promoter activates transcription of the human germ-line C alpha1 gene for IgA1 and mediates the transforming growth factor (TGF)-beta1 responsiveness of this locus. Here we show that the I alpha1 promoter contains several binding sites for the AML/PEBP2/CBF family of transcription factors and that AML and Ets proteins are major regulators of the basal and TGF-beta-inducible promoter activity. Our data constitute a starting point for studies to elucidate the molecular mechanism by which TGF-beta regulates IgA production.
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Affiliation(s)
- X Q Xie
- Department of Cell and Molecular Biology, Umeå University, Sweden
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Xie XQ, Pavlopoulos S, DiMeglio CM, Makriyannis A. Conformational studies on a diastereoisomeric pair of tricyclic nonclassical cannabinoids by NMR spectroscopy and computer molecular modeling. J Med Chem 1998; 41:167-74. [PMID: 9457240 DOI: 10.1021/jm960410r] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Among the nonclassical cannabinoids, CP-55,244 (4), which incorporates an axial 14 beta-hydroxymethyl group, is pharmacologically 30 times more potent than its prototype CP-47,497 (2) and 300 times more potent than delta 9-THC (1). It has a high degree of stereoselectivity (about 120:1) with respect to its diastereoisomer, CP-97,587 (5), which differs structurally by having the 14-hydroxymethyl group equatorial. Conformational studies of 4 and 5 were carried out using 2D NMR spectroscopy and molecular modeling in order to define and compare the similarities and differences between them. Specific structural features of interest are the conformation of the 1',1'-dimethylheptyl (DMH) side chain, the conformation of the cyclohexyl rings, the orientation of the phenolic ring (A ring) relative to the cyclohexyl ring (C ring), and the orientation of the hydroxymethyl group as well as the formation of intramolecular hydrogen bonding. Our results show that the conformations of the phenolic hydroxyl (Ph-OH) and DMH side chain for 4 are similar to those of 2. The proton of the phenolic hydroxyl is pointing away from the C ring while the DMH chain randomly adopts one of four dynamically averaged conformers in which it is almost perpendicular to the plane of the aromatic ring. The relative orientation of the A and C rings is such that the two rings interconvert between two low-energy conformations. Compound 5 prefers the conformer with the Ph-OH pointing toward the alpha-face of the cyclohexyl ring, while for 4, there is an increased preference for the conformer where the Ph-OH is directed toward the beta face. This may be due to intramolecular H-bonding between the Ph-OH and the axial 14 beta-hydroxymethyl group of 4 that stabilizes this conformation. Hydrogen bonding between the Ph-OH and the equatorial-14 alpha-hydroxymethyl of 5 was not detected. Thus, the orientation of the aliphatic hydroxyl group with respect to the D ring in 4 and 5 may play an important role with regard to the pharmacophoric requirements of the two analogs for the cannabinoid receptor and provide an explanation for the observed differences in their biological properties.
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Affiliation(s)
- X Q Xie
- Institute of Materials Science, School of Pharmacy, University of Connecticut, Storrs 06269, USA
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Xie XQ, Moring J, Makriyannis A. Differential scanning calorimetry and small angle x-ray diffraction study of the interaction of (R)-PAF, (R)-ET-18-OME and (R)-Lyso-PAF with model membranes. Life Sci 1997; 61:909-23. [PMID: 9284084 DOI: 10.1016/s0024-3205(97)00593-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
(R)-PAF, (R)-ET-18-OMe and (R)-Lyso-PAF are ether phospholipid analogs exhibiting different biological activities. All three molecules are highly lipophilic and interact with cell membranes. The manner in which their interactions occur is relevant to their biological activities and may provide information on their mechanism(s) of action at the molecular level. We have studied the interactions of (R)-PAF, (R)-ET-18-OMe and (R)-Lyso-PAF with model membranes using differential scanning calorimetry (DSC). A concentration-dependence study with DSC shows that all three analogs induce similar changes in the thermotropic behavior of model membranes. All produce a slight decrease in the main phase transition temperature of DPPC bilayers (deltaTc = 0.3 to 1.4 degrees C) but have a more substantial effect on the pretransition (deltaTc = 0.8 to 4.5 degrees C). All three disorder phosphatidylcholine (PC) membranes but impart order to PC/cholesterol membranes. We have used small angle x-ray diffraction experiments to supplement the DSC evidence on the topography of the ether lipid analogs in the bilayers. All three appear to insert themselves in the bilayer with their long chain parallel with the membrane bilayer chains.
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Affiliation(s)
- X Q Xie
- Institute of Materials Science, School of Pharmacy, University of Connecticut, Storrs 06269, USA
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Busch-Petersen J, Hill WA, Fan P, Khanolkar A, Xie XQ, Tius MA, Makriyannis A. Unsaturated side chain beta-11-hydroxyhexahydrocannabinol analogs. J Med Chem 1996; 39:3790-6. [PMID: 8809166 DOI: 10.1021/jm950934b] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The cannabinoid side chain is a key pharmacophore in the interaction of cannabinoids with their receptors (CB1 and CB2). To study the stereochemical requirements of the side chain, we synthesized a series of cannabinoids in which rotation around the C1'-C2' bond is blocked. The key steps in the synthesis were the cuprate addition of a substituted resorcinol to (+)-apoverbenone, the TMSOTf-mediated formation of the dihydropyran ring, and the stereospecific introduction of the beta-11-hydroxymethyl group. All the analogs tested showed nanomolar affinity for the receptors, the cis-hept-1-ene side chain having the highest affinity for CB1 (Ki = 0.89 nM) and showing the widest separation between CB1 and CB2 affinities. The parent n-heptyl-beta-11-hydroxyhexahydrocannabinol was the least potent binding to CB1 (Ki = 8.9 nM) and had the lowest selectivity between CB1 and CB2.
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Affiliation(s)
- J Busch-Petersen
- Department of Chemistry, University of Hawaii, Honolulu 96822, USA
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Abstract
During a search for novel drugs possessing analgesic properties but devoid of the psychotropic effects of marijuana, a group of molecules designated as nonclassical cannabinoids was synthesized by Pfizer. Of these nonclassical cannabinoids CP-55,940 has received the most attention principally because it was used as the high affinity radioligand during the discovery and characterization of the G-protein-coupled cannabinoid receptor. In an effort to obtain information on the stereoelectronic requirements at the cannabinoid receptor active site, we have studied the conformational properties of CP-55,940 using a combination of solution NMR and computer modeling methods. Our data show that for the most energetically favored conformation, (i) the aromatic phenol ring is perpendicular to the cyclohexane ring, and the phenolic O-H bond is coplanar with the aromatic ring and points away from the cyclohexyl ring; ii) the dimethylheptyl chain adopts one of four preferred conformations in all of which the chain is almost perpendicular to the phenol ring; and iii) an intramolecular H-bond between the phenolic and hydroxypropyl groups allows all three hydroxyl groups of CP-55,940 to be oriented toward the upper face of the molecule. Such an orientation by the OH groups may be a characteristic requirement for cannabimimetic activity.
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Affiliation(s)
- X Q Xie
- Institute of Materials Science, School of Pharmacy, University of Connecticut, Storrs 06269, USA
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25
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Abstract
Aminoalkylindoles (AAIs) are structurally dissimilar from the classical cannabinoids (CCs), however, both AAIs and CCs appear to bind at the same site on the cannabinoid receptor. To obtain better insights on the structural correlation between AAIs and CCs, we have studied the conformational properties of the potent cannabimimetic AAI WIN 55212-2 and its inactive analogs using high resolution 2D NMR spectroscopy in combination with computer-assisted molecular modeling. The pharmacophoric similarities between the AAIs and the CCs were then investigated using superimposition techniques. The absolute stereochemistries of the biologically active enantiomer (-)HHC were used as superimposition points and considered as internal controls in order to test the molecular principles guiding this experiment. Our results show that the model is congruent with a superimposition in which the naphthoyl, morpholino and 3-keto groups in the AAI, respectively correspond to the side chain, cyclohexanol OH and phenolic OH of HHC. A good fit is obtained when the two biologically active antipodes are superimposed. Conversely, the fit is poor if the inactive AAI enantiomer is superimposed on the active HHC enantiomer. It can also be seen that in such an orientation a certain deviation of the C-ring from the plane of the phenol ring of the tricyclic HHC component and of the morpholinyl portion from the plane of the indole ring of WIN 55212-2 is essential for cannabimimetic activity. The inactive enantiomer WIN 55212-3 has its respective components aligned in the opposite quadrant. By comparing the stereoelectronic features of representative AAIs and CCs, we have developed a model which may help to uncover the pharmacophoric requirements of the AAIs and serve as a basis for future SAR and drug design.
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Affiliation(s)
- X Q Xie
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs 06269, USA
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Xie XQ, Yang DP, Melvin LS, Makriyannis A. Conformational analysis of the prototype nonclassical cannabinoid CP-47,497, using 2D NMR and computer molecular modeling. J Med Chem 1994; 37:1418-26. [PMID: 8182700 DOI: 10.1021/jm00036a006] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In an effort to determine the stereochemical requirements for pharmacological activity among the series of nonclassical cannabinoids synthesized at Pfizer, we have studied the conformational properties of the parent bicyclic analog CP-47,497. For this study, we have used a combination of solution NMR and theoretical computational approaches. The energetically favored conformation has the phenolic ring almost perpendicular to the cyclohexanol ring which exists in a chair conformation. The OH bond of the phenol is preferentially coplanar with the aromatic ring and points toward the C2 ring proton, while the dimethylheptyl side chain adopts a conformation almost perpendicular to the aromatic ring. The conformational features of this nonclassical cannabinoid analog closely resemble those of its classical counterparts. The only apparent difference is the small dihedral angle (psi 1 = 62 degrees) between the planes of the two rings of CP-47,497 compared to that of the tricyclic tetrahydro- or hexahydrocannabinol analogs (psi 1 = 137 degrees). However, CP-47,497 can be perfectly superimposed over the respective tricyclic analog by rotation around the Ph-cyclohexyl bond (C6-C7 bond) and assume a conformation which is energetically higher than the preferred one by 3.0 kcal/mol. It can be argued that such a conformation may be acquired by the nonclassical analog during its interaction with the active site.
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Affiliation(s)
- X Q Xie
- Section of Medicinal Chemistry and Pharmacognosy, School of Pharmacy, University of Connecticut, Storrs 06269
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