天然氘核磁共振法测定环酮的烯胺化反应的一级动力学氘同位素效应

长期以来,测定动力学氘同位素效应都是利用在分子中特定位置富集氘的化合物。最近章本礼等提出了利用普通化合物的氘核磁谱测定动力学氘同位素效应的方法,由于此法不用特别氘代化合物,因而使氘同位素效应的测定工作大大简化。自从六十年代以来,烯胺作为烯醇负离子的替代物在有机合成中得到了广泛的应用。     

马来酸氟伏沙明-D3的合成

以4-苄氧基-1-丁醇（2）为起始原料,氘代碘甲烷为氘代试剂,经氘代甲基化、氢化脱苄、溴化、格氏反应、戴斯-马丁氧化、缩合、取代、成盐等反应,以51.7%总收率合成了稳定同位素标记的马来酸氟伏沙明-D₃（1）。该合成方法原料易得、操作简单、重现性好。目标化合物的结构经核磁共振和高分辨质谱确认,可用于药代动力学研究     

靶向葡萄糖转运蛋白(GLUTs)抗癌药物的开发

基于肿瘤细胞与正常细胞葡萄糖代谢差异的肿瘤沃伯格效应,是目前新型靶向抗肿瘤药物开发的研究热点之一。本文以沃伯格效应的代谢特征和特异性生物标识物为出发点,从靶向葡萄糖转运蛋白(GLUTs)生物靶点和利用肿瘤葡萄糖代谢亢进的生物特征这两个层面,综述了具有代表性的GLUTs抑制剂以及GLUTs靶向型糖偶联抗肿瘤药物的研发现状,讨论并解析通过靶向沃伯格效应开发抗肿瘤药物的设计思路、实施策略与推广前景。     

光、电催化合成氘代化学品和药物分子研究综述

稳定氘同位素因其安全、易控制、廉价易得等优势而被广泛应用于探究有机反应机理和揭示药物及其代谢物的吸收、分布、代谢和排泄过程.此外,氘标记药物也被称为重氢药、重药,即把药物分子上处于代谢位点的一个或多个碳氢键(C-H)用碳氘键(C-D)替代获得的新药,以延长药物代谢周期、减少进入血液前的代谢、减少有毒代谢物产生,从而降低给药剂量、提高安全性以及获得更佳的疗效.2017年4月,第一例氘代新药,氘代四苯喹嗪(海外商品名Austedo,国内商品名:安泰坦)被美国食品药品监督管理局批准,氘代新药市场被彻底激活.临床数据显示,丁苯那嗪原药具有严重的毒副作用,19%的病人使用后表现出抑郁病症,严重者甚至有自杀倾向;氘代丁苯那嗪相对于原药,代谢动力学特征明显改善,毒副作用显著降低.目前,国内外已有多家知名药企(如BMS,Concert,Teva,苏州泽璟生物制药以及成都海创等)布局氘代新药研发.2021年6月,中国国家药品监督管理局正式批准苯磺酸多纳非尼片(商品名:泽普生),用于治疗既往未接受过全身系统性治疗的不可切除肝细胞癌患者.氘代药物的蓬勃发展使得对其精准合成提出了更高的要求和更强烈的需求.氢氘交换等传统方法由于反应条件苛刻、氘源昂贵、氘代个数和位点难以精准控制等限制,难以满足新时代氘代药物的发展需要.近年,化学家开始致力于开发温和、精准氘代新方法,其中,光或电驱动的温和、精准氘标记方法引起了广泛关注.本综述着重总结近五年光/电驱动的温和、精准的氘代方法的研究进展.基于氘原子引入的反应模式分为以下三种类型.(1)氘原子转移策略:以光/电催化单电子转移或者氢原子转移方式生成自由基中间体R^?;随后,R^?与氘原子转移试剂(由硫醇和重水原位制得)反应,得到相应的氘代产物R-D.利用该策略,目前已发展了羧酸、卤代烃、硫醚(醇)等的去官能化氘代反应以及硅烷、叔胺、醛基等的氢氘交换反应.(2)氘原子攫取策略:以光/电催化单电子转移、氢原子转移或者能量转移方式生成自由基R^?中间体,一方面,以产物碳氘键键能大于溶剂碳氘键键能为驱动力,使R^?直接从氘代溶剂中攫取氘原子制得相应的氘代产物R-D;另一方面,利用光/电催化强驱动力,使R^?再次获得一个电子形成相应负离子,从而顺利从重水中攫氘,制得相应的氘代产物R-D.利用该策略,目前已开发了羧酸、重氮、卤代物等的去官能化氘代反应,以及亚胺的加氘还原反应.(3)重水分解策略:基于光/电催化水分解制氢原理,以光或电为驱动力分解重水,使其产生高活性氘物种,原位耦合还原氘代反应.利用该策略,目前已开发了以重水为氘源的卤代物,不饱和官能团(包括烯烃、炔烃、亚胺和芳基酮等)等的氘代还原反应以及伯、仲胺的氘甲基化反应.本综述归纳了近年来光或电催化驱动的温和、精准氘代方法研究进展.在此基础上结合课题组在该领域的研究经历,分析了药物和精细化学品精准氘代面临的关键挑战和重要机遇,包括:发展温和、精准的不对称催化氘代方法用于制备手性氘代药物;针对复杂药物多个代谢位点,实现精准、可控氘代,从而更有效调节药物代谢动力学和代谢产物.此外,光合成、电合成迅猛发展也将为氘代精细化学品和药物光、电催化合成带来新的机遇.     

稳定同位素标记D_4-罗丹明B的合成及表征

以全氘代邻二甲苯为同位素标记前体,经氧化得到的D_4-邻苯二甲酸与3-羟基-N,N-二乙基苯胺反应生成稳定同位素标记的D_4-罗丹明B,总收率36.9%。目标产物的结构经质谱(MS)、核磁(NMR)等技术手段表征确认,通过高效液相色谱确定化学纯度高于98.0%,同位素氘丰度大于98.0%。将其作为同位素内标试剂用于果汁中罗丹明B的残留检测,在0.05~50 mg/L范围内呈良好的线性关系,其检出限为5μg/kg,回收率为96.4%~103.4%,相对标准偏差(RSD)为1.0%~1.2%,具有很高的灵敏度和准确性。为食品安全领域违禁色素的检测提供了一种可靠实用的方法。     

天然氘核磁共振测定一级和二级动力学氘同位素效应I. 内标的分子内与分子间竞争法

应用氘核磁共振,而不用特别氘代化合物同时测定一级和二级动力学氘同位素效应,其特点是采用外标,并同时考虑分子内和分子间竞争,用建立的方法测定甲苯、乙苯及异丙苯的一级、α-及β-二级效应值。     

两种氨基酸中[MH-CO_2H_2]~ 的特征质谱碎裂

运用低能碰撞诱导解离（CID）研究了电子轰击（EI）、快原子轰击（FAB）电离条件下质子化亮氨酸与异亮氨酸解高产生亚稳离子［MH－CO2H2］＋的单分子质谱碎裂，二种异构体呈现出了各自不同的解离特征，根据CID的特征碎片离子和氘代同位素标记实验，提出了其碎裂过程存在离子／中性（碎片）复合物中间体碎裂机理，并对有关的特征离子的形成进行了讨论．     

2—羟基—4—邻苯二甲酰亚胺基丁酸的氢迁移反应

在甲烷为反应气的化学电离质谱条件下，质子化的２－羟基－４－邻苯二甲酰亚胺基丁酸的单分子质谱碎裂产生了ｍ／ｚ１４８的碎片离子，表明其碎裂过程发生了氢迁移反应，ＡＭ在分子轨道的理论计算结果为可能的质子化位置提供了理论依据；建立在氘代同位素标记和碰撞诱导解离实验的基础上，我们提出此离子的形成可能同时存在单氢迁移和双氢迁移，一些质谱图中的物征碎片中离子为可能的ＭｃＬａｆｆｅｒｔｙ重排和离子／中性（碎片）复     

基于液相色谱-质谱联用的代谢组学技术研究Pokemon诱导的胞内脂代谢变化

Pokemon是一种转录抑制因子,能够通过影响染色质的重组或直接与抑癌基因结合而抑制抑癌基因的转录,促使肿瘤形成。该文利用基于液相色谱-质谱联用的代谢组学技术研究了Pokemon在肝癌中调控细胞代谢的作用机制。通过脂质转染,获得了Pokemon高表达的HL7702细胞,分别收集转染后不同时间点的细胞。利用基于液相色谱-质谱联用技术的代谢组学方法,分析胞内代谢物的成分。根据多元统计分析的结果选出差异显著的候选代谢物,通过数据库（METLIN和HMDB）检索、二级图谱比对进行结构解析,确证了36种代谢物。通过KEGG数据库检索发现这些代谢物主要与脂质合成相关。进一步分析发现脂质合成途径中乙酰辅酶羧化酶和脂肪酸合成酶均被激活。结果显示,Pokemon可通过激活细胞中脂质合成通路而影响细胞的代谢。     

双羟甲基和双甲氧甲酰基取代的双(二硫代亚乙基)四硫代 富瓦烯的合成

合成了双羟甲基及双甲氧甲酰基取代的双(二硫代亚乙基)四硫代富瓦烯,给出了它们的质谱、核磁共振氢谱和碳谱,并讨论了影响反应的一些因素。     

Cancer cell metabolism: implications for therapeutic targets

Cancer cell metabolism is characterized by an enhanced uptake and utilization of glucose, a phenomenon known as the Warburg effect. The persistent activation of aerobic glycolysis in cancer cells can be linked to activation of oncogenes or loss of tumor suppressors, thereby fundamentally advancing cancer progression. In this respect, inhibition of glycolytic capacity may contribute to an anticancer effect on malignant cells. Understanding the mechanisms of aerobic glycolysis may present a new basis for cancer treatment. Accordingly, interrupting lactate fermentation and/or other cancer-promoting metabolic sites may provide a promising strategy to halt tumor development. In this review, we will discuss dysregulated and reprogrammed cancer metabolism followed by clinical relevance of the metabolic enzymes, such as hexokinase, phosphofructokinase, pyruvate kinase M2, lactate dehydrogenase, pyruvate dehydrogenase kinase and glutaminase. The proper intervention of these metabolic sites may provide a therapeutic advantage that can help overcome resistance to chemotherapy or radiotherapy.     

N-苄基十六碳酰胺促小鼠Leydig细胞增殖和分泌睾酮的1H NMR代谢组学研究

采用基于核磁共振氢谱(¹H NMR)的细胞代谢组学技术探讨了玛咖有效成分N-苄基十六碳酰胺(NBH)促进小鼠Leydig细胞增殖和分泌睾酮的作用机制. 测定了小鼠Leydig细胞在给药前后的细胞增殖率和细胞培养液中的睾酮含量, 采用主成分分析和正交偏最小二乘判别分析, 研究了小鼠Leydig细胞在给药前后细胞破碎液中的代谢物差异, 并进行了代谢通路分析. 实验结果表明, NBH能提高小鼠Leydig细胞增殖率和睾酮分泌量, 给药后小鼠Leydig细胞破碎液中的代谢轮廓明显改变, 共鉴定亮氨酸、 赖氨酸、 鲨肌醇、 缬氨酸和丙氨酸等24种差异代谢物. 经Metaboanalyst分析发现, 差异代谢物主要涉及丙氨酸/天冬氨酸/谷氨酸代谢、 甘氨酸/丝氨酸/苏氨酸代谢、 谷胱甘肽代谢及丙酮酸代谢等10条新陈代谢和遗传信息处理代谢通路, 初步阐明了NBH通过调节上述代谢通路的相关节点发挥促进小鼠Leydig细胞增殖和分泌睾酮作用.     

气相色谱-质谱和液相色谱-质谱联用方法用于口腔癌代谢组学分析

口腔癌的发病率占全身恶性肿瘤的第6位,正确区分正常状态与良性和恶性口腔肿瘤,是恰当选择治疗方案的关键所在。本研究中,首先利用液相色谱-质谱和气相色谱-质谱联用方法分别得到健康人、良性口腔肿瘤患者和恶性口腔肿瘤患者血浆、尿液和唾液的代谢轮廓,然后应用正交信号校正的偏最小二乘法进行多变量统计分析。结果表明健康人、良性肿瘤患者和恶性肿瘤患者在血浆、尿液和唾液等3种体液代谢中都可以被区分开,而且找到和鉴定出19个重要差异代谢物。相关代谢通路分析显示,与健康人相比,良性和恶性口腔肿瘤患者都存在能量代谢紊乱和脂类代谢失衡的现象,但恶性口腔肿瘤患者还表现出三羧酸循环和肌醇代谢异常,这为临床诊断及治疗提供了重要信息。     

Metabolomics of colorectal cancer: past and current analytical platforms

Metabolomics is coming of age as an important area of investigation which may help reveal answers to questions left unanswered or only partially understood from proteomic or genomic approaches. Increased knowledge of the relationship of genes and proteins to smaller biomolecules (metabolites) will advance our ability to diagnose, treat, and perhaps prevent cancer and other diseases that have eluded scientists for generations. Colorectal tumors are the second leading cause of cancer mortality in the USA, and the incidence is rising. Many patients present late, after the onset of symptoms, when the tumor has spread from the primary site. Once metastases have occurred, the prognosis is significantly worse. Understanding alterations in metabolic profiles that occur with tumor onset and progression could lead to better diagnostic tests as well as uncover new approaches to treat or even prevent colorectal cancer (CRC). In this review, we explore the various analytical technologies that have been applied in CRC metabolomics research and summarize all metabolites measured in CRC and integrate them into metabolic pathways. Early studies with nuclear magnetic resonance and gas-chromatographic mass spectrometry suggest that tumor cells are characterized by aerobic glycolysis, increased purine metabolism for DNA synthesis, and protein synthesis. Liquid chromatography, capillary electrophoresis, and ion mobility, each coupled with mass spectrometry, promise to advance the field and provide new insight into metabolic pathways used by cancer cells. Studies with improved technology are needed to identify better biomarkers and targets for treatment or prevention of CRC.

Revealing the metabolic mechanism of dandelion extract against A549 cells using UPLC-QTOF MS

Dandelion extract exhibits potential anticancer activity and is expected to be a new type of natural anticancer drug. However, the effect mechanism of dandelion extract to lung cancer cells is still unclear. Here, untargeted metabolomics approach based on LC–MS was used to characterize the metabolic responses of A549 cells to dandelion extract exposure and to provide new clues for the antitumor mechanism of dandelion extract from the metabolomics perspective. A total of 16 differentially expressed and time-related metabolites were identified between dandelion extract exposure and control groups. The perturbed metabolic pathways of A549 cells after dandelion extract exposure mainly include the glycerophospholipid metabolism and purine metabolism. These results concluded that dandelion extract may exert anticancer activity by affecting malignant proliferation, disturbing the stability of cell membrane structure, reducing the adhesion of tumor cells to extracellular matrix and fibronectin, and finally inducing tumor cell death.     

Metabolomics approach based on utra-performance liquid chromatography coupled to mass spectrometry with chemometrics methods for high-throughput analysis of metabolite biomarkers to explore the abnormal metabolic pathways associated with myocardial dysfunction

Ultra-performance liquid chromatography/mass spectrometry-based metabolomics can been used for discovery of metabolite biomarkers to explore the metabolic pathway of diseases. Identification of metabolic pathways is key to understanding the pathogenesis and mechanism of disease. Myocardial dysfunction induced by sepsis (SMD) is a severe complication of septic shock and represents major causes of death in intensive care units; however its pathological mechanism is still not clear. In this study, ultrahigh-pressure liquid chromatography with mass spectrometry-based metabolomics with chemometrics anaylsis and multivariate pattern recognition analysis were used to detect urinary metabolic profile changes in a lipopolysaccharide-induced SMD mouse model. Multivariate statistical analysis including principal component analysis and orthogonapartial least squares discriminant analysis for the discrimination of SMD was conducted to identify potential biomarkers. A total of 19 differential metabolites were discovered by high-resolution mass spectrometry-based urinary metabolomics strategy. The altered biochemical pathways based on these metabolites showed that tyrosine metabolism, phenylalanine metabolism, ubiquinone biosynthesis and vitamin B6 metabolism were closely connected to the pathological processes of SMD. Consequently, integrated chemometric analyses of these metabolic pathways are necessary to extract information for the discovery of novel insights into the pathogenesis of disease.     

An Enzyme-Loaded Metal–Organic Framework-Assisted Microfluidic Platform Enables Single-Cell Metabolite Analysis

Colonization of cancer cells at secondary sites, a decisive step in tumor metastasis, is strongly dependent on the formation of metastatic microenvironments regulated by intrinsic single-cell metabolism traits. Herein, we report a single-cell microfluidic platform for high-throughput dynamic monitoring of tumor cell metabolites to evaluate tumor malignancy. This microfluidic device empowers efficient isolation of single cells (>99 %) in a squashed state similar to tumor extravasation, and employs enzyme-packaged metal–organic frameworks to catalyze tumor cell metabolites for visualization. The microfluidic evaluation was confirmed by in vivo assays, suggesting that the platform allowed predicting the tumorigenicity of captured tumor cells and screening metabolic inhibitors as anti-metastatic drugs. Furthermore, the platform efficiently detected various aggressive cancer cells in unprocessed whole blood samples with high sensitivity, showing potential for clinical application.     

Comprehensive Profiling by Non-targeted Stable Isotope Tracing Capillary Electrophoresis-Mass Spectrometry: A New Tool Complementing Metabolomic Analyses of Polar Metabolites

Mass spectrometry (MS) driven metabolomics is a frequently used tool in various areas of life sciences; however, the analysis of polar metabolites is less commonly included. In general, metabolomic analyses lead to the detection of the total amount of all covered metabolites. This is currently a major limitation with respect to metabolites showing high turnover rates, but no changes in their concentration. Such metabolites and pathways could be crucial metabolic nodes (e.g., potential drug targets in cancer metabolism). A stable-isotope tracing capillary electrophoresis–mass spectrometry (CE-MS) metabolomic approach was developed to cover both polar metabolites and isotopologues in a non-targeted way. An in-house developed software enables high throughput processing of complex multidimensional data. The practicability is demonstrated analyzing [U-¹³C]-glucose exposed prostate cancer and non-cancer cells. This CE-MS-driven analytical strategy complements polar metabolite profiles through isotopologue labeling patterns, thereby improving not only the metabolomic coverage, but also the understanding of metabolism.     

Metabolomics: a revolution for novel cancer marker identification

The repertoire of small-molecular-weight substances present in cells, tissue and body fluids are known as the metabolites. The global analysis of metabolites, such as by high-resolution 1H nuclear magnetic resonance spectroscopy and mass spectrometry, is integral to the rapidly expanding field of metabolomics, which is making progress in various diseases. In the area of cancer and metabolic phenotype, the integrated analysis of metabolites may provide a powerful platform for detecting changes related to cancer diagnosis and discovering novel biomarkers. In this review, metabolomics including the technologies in metabolomics research and extracting information from metabolomics datasets are described. Then we discuss the challenges and opportunities in metabolomics for finding metabolic processes in cancer and discovering novel cancer biomarkers. Finally, we assess the clinical applicability of metabolomics.