Yeast and drug discovery

Advanced genetic techniques, along with the high degree of conservation of basic cellular processes, have made the yeast Saccharomyces cerevisiae a valuable system for identification of new drug targets, target-based and non-target-based drug screening, and detailed analysis of the cellular effects of drugs. Yeast also presents a convenient system for antifungal drug discovery because it is closely related to Candida albicans, a major human pathogen. Many yeast genes remain poorly characterized, and most of the sophisticated techniques in yeast have been in widespread use less than a decade – a period shorter than the typical cycle from target identification to marketing approval for a new drug. It is likely that most of the benefits of yeast in discovery and development of therapeutic compounds have yet to be realized. Electronic Publication     

高通量测序在病原微生物耐药方面的应用进展

高通量测序是一种高效、准确、价廉的新型测序技术,随着近年来的不断推广,逐渐进入不同的研究领域。目前,多重耐药菌的感染给患者和社会增加了巨大负担,耐药机制和抗菌药物的研发是科学研究的热点之一。高通量测序技术也开始在病原微生物耐药方面发挥了巨大作用,尤其是在耐药机制研究方面,解决了一些用现有的技术无法解决的问题。本文从病原菌鉴定、耐药机制、药物新靶标、耐药菌流行病学以及用药指导等方面阐述了高通量测序在病原微生物耐药方面的应用及进展,重点讨论了耐药机制和抗菌药物新靶标进展以及现阶段存在的问题。高通量测序技术不断发展,尤其是进入病原微生物研究领域后延伸出新的研究技术和方法,随着相关的生物信息学的进步,此项技术应用将会更加广泛。     

Formulations for delivery of therapeutic proteins

Advances in biotechnology have now created a capacity to produce therapeutically active proteins on a commercial scale, opening the potential for their application in an array of disease conditions. The process of translation of the variety of different therapeutic proteins into the medicines used in clinics is now occurring. To assist in this translation, new formulations to deliver proteins could play an important role. These new formulations need to more adequately address the pharmacological and therapeutic requirement for each particular protein/peptide and, in that way, either improve present therapies or extend with new entries the current list of protein based medicines used in clinic.

亚洲小车蝗痘病毒增效因子的初步研究

OaEPV经2×SDS包涵体碱性裂解缓冲液裂解,离心,分别用上清液及沉淀与绿僵菌孢子混合感染黄胫小车蝗,上清液的增效活性比沉淀大2.5倍.用三种不同方法(2×SDS包涵体碱性裂解液法,0.02 mol/L NaOH裂解法,8 mol/L尿素裂解法)裂解OaEPV所得蛋白液与绿僵菌混用,生测结果表明,包涵体裂解液法制备所得蛋白增效活性最高,NaOH裂解法次之,尿素裂解法制备的蛋白几乎没有增效活性.将OaEPV用包涵体碱性裂解液裂解后,用葡聚糖G-200 凝胶柱层析进行分离,出现两个洗脱峰,这两个峰的洗脱液浓缩后进行生物测定,初步表明增效作用主要为第二个峰的蛋白片段.经SDS-聚丙烯酰胺凝胶电泳,第二个峰的蛋白片段的分子量为40 kDa左右.     

Molecularly imprinted polymers for drug delivery

Molecular imprinting technology has an enormous potential for creating satisfactory drug dosage forms. Although its application in this field is just at an incipient stage, the use of MIPs in the design of new drug delivery systems (DDS) and devices useful in closely related fields, such as diagnostic sensors, is receiving increasing attention. Examples of MIP-based DDS can be found for the three main approaches developed to control the moment at which delivery should begin and/or the drug release rate, i.e. rate-programmed, activation-modulated, or feedback-regulated drug delivery. The utility of these systems for administering drugs by different routes (e.g. oral, ocular or transdermal) or trapping undesired substances under in vivo conditions is discussed. This review seeks to highlight the more remarkable advantages of the imprinting technique in the development of new efficient DDS as well as pointing out some possibilities to adapt the synthesis procedures to create systems compatible with both the relative instable drug molecules, especially of peptide nature, and the sensitive physiological tissues with which MIP-based DDS would enter into contact when administered. The prospects for future development are also analysed.     

Optimization of Antiviral Prodrug Properties Using Combinatorial Methods

Abstract

Some diacid biodegradable synthesis of aziduthymidine (AZT) were synthesized and applied to production of about 60 different derivatives.     

基于转录组测序分析人大细胞肺癌NCI-H460细胞对类泛素化抑制剂MLN4924的潜在耐药机制

目的探讨人大细胞肺癌NCI-H460细胞对类泛素化抑制剂MLN4924潜在新型耐药机制。 方法利用MLN4924处理NCI-H460细胞,筛选和建立耐药细胞株。对普通NCI-H460对照细胞、MLN4924处理8 h加药细胞株、48 h加药细胞株和建立成功的耐药株进行高通量转录组测序。根据测序结果筛选差异表达基因,并进行通路富集分析。多组间比较采用单因素方差分析,组间两两比较采用Dunnett-t检验。 结果共构建3个NCI-H460耐药细胞株。转录组测序分析显示,与对照比较,MLN4924处理8 h加药株、处理48 h加药株、三株耐药株分别筛选出5 303、4 186、3 388、3 675和3 267个差异表达基因,包括ABCA9、ABCA13、CYR61和CYP39A1等基因。RT-qRCR实验进一步验证了在瞬时加药组和耐药株中ABCA9和CYR61基因高表达。GO富集分析结果显示,差异表达基因与细胞周期、细胞凋亡、细胞间信号转导和细胞黏附等细胞生物过程高度相关,还与细胞核和细胞膜等细胞组分密切相关。KEGG通路富集分析结果显示,耐药细胞中差异表达基因集中在MAPK信号通路、PI3K/Akt信号通路和cAMP信号通路等。 结论在人大细胞肺癌NCI-H460细胞中,ABCA9、CYR61、ABCC8和CYP4F12等基因的表达变化可能会提高其对MLN4924的耐药能力。这种耐药能力可能与MAPK信号通路、PI3K/Akt信号通路和cAMP信号通路有关。     

Cytotoxicity, intracellular distribution and uptake of doxorubicin and doxorubicin coupled to cell-penetrating peptides in different cell lines: A comparative study

One of the major obstacles which are opposed to the success of anticancer treatment is the cell resistance that generally develops after administration of commonly used drugs. In this study, we try to overcome the tumour cell resistance of doxorubicin (Dox) by developing a cell-penetrating peptide (CPP)-anticancer drug conjugate in aim to enhance its intracellular delivery and that its therapeutic effects. For this purpose, two cell-penetrating peptides, penetratin (pene) and tat, derived from the HIV-1 TAT protein, were chemically conjugated to Dox. The cytotoxicity, intracellular distribution and uptake were accessed in CHO cells (Chinese Hamster Ovarian carcinoma cells), HUVEC (Human Umbilical Vein Endothelial Cells), differentiated NG108.15 neuronal cell and breast cancer cells MCF7drug-sensitive or MDA-MB 231 drug-resistant cell lines. The conjugates showed different cell killing activity and intracellular distribution pattern by comparison to Dox as assessed respectively by MTT-based colorimetric cellular cytotoxicity assay, confocal fluorescence microscopy and FACS analysis. After treatment with 3 μM with Dox-CPPs for 2 h, pene increase the Dox cytotoxicity by 7.19-fold in CHO cells, by 11.53-fold in HUVEC cells and by 4.87-fold in MDA-MB 231 cells. However, cytotoxicity was decreased in NG108.15 cells and MCF7. Our CPPs-Dox conjugate proves the validity of CPPs for the cytoplasmic delivery of therapeutically useful molecules and also a valuable strategy to overcome drug resistance.     

Receptor-targeted nanocarriers for therapeutic delivery to cancer

Abstract

Efficient and site-specific delivery of therapeutic drugs is a critical challenge in clinical treatment of cancer. Nano-sized carriers such as liposomes, micelles, and polymeric nanoparticles have been investigated for improving bioavailability and pharmacokinetic properties of therapeutics via various mechanisms, for example, the enhanced permeability and retention (EPR) effect. Further improvement can potentially be achieved by conjugation of targeting ligands onto nanocarriers to achieve selective delivery to the tumour cell or the tumour vasculature. Indeed, receptor-targeted nanocarrier delivery has been shown to improve therapeutic responses both in vitro and in vivo. A variety of ligands have been investigated including folate, transferrin, antibodies, peptides and aptamers. Multiple functionalities can be incorporated into the design of nanoparticles, e.g., to enable imaging and triggered intracellular drug release. In this review, we mainly focus on recent advances on the development of targeted nanocarriers and will introduce novel concepts such as multi-targeting and multi-functional nanoparticles.     

聚乙二醇- 聚乳酸嵌段共聚物纳米粒的研究进展

聚乙二醇-聚乳酸嵌段共聚物(PEG-PLA)及其端基衍生物纳米粒可以增强载药量、降低突释效应、提高药物在血液中的循环时间、提高生物利用度,并且其粒径更小,能以被动靶向的方式聚集于炎症或靶向部位。本文综述了PEG-PLA嵌段共聚物纳米粒的最新进展,包括PEG-PLA的合成、纳米粒的制备、释药特性及在药物制剂中的应用。     

Modification of sterculia gum with methacrylic acid to prepare a novel drug delivery system

The present paper deals with the modification of the sterculia gum with methacrylic acid (MAAc) to hydrogels for use in drug delivery. The hydrogels were characterized by SEMs, FTIR and swelling studies. The release dynamics of model anti-ulcer drug (ranitidine hydrochloride) from the hydrogels has been studied for the evaluation of the release mechanism. The values of the diffusion exponent 'n' (0.55, 0.54 and 0.59) and gel characteristic constant 'k' (2.109 x 10(-2), 3.698 x 10(-2) and 2.427 x 10(-2)) have been obtained, respectively, in distilled water, pH 2.2 buffer and pH 7.4 buffer. The release of the drug from the hydrogels occurred through non-Fickian diffusion mechanism.     

聚乳酸羟基乙酸纳米微球在肿瘤药物递送中的应用

药物递送载体的应用使得小分子药物、蛋白质药物,以及基因药物能够通过多种给药方式用于癌症的治疗。聚乳酸-羟基乙酸共聚物因其具有良好的生物相容性及生物可降解性,成为广泛采用的抗癌药物载体之一,可以通过静脉、皮下、口服等多种给药途径用于化疗、基因治疗、蛋白治疗给药及接种免疫等诸多方面,显示了良好的应用前景。     

不同钙-醇溶解体系丝素蛋白的制备及表征研究

采用 ４种中性盐溶液 Ｃａ（ＮＯ３）２４Ｈ２Ｏ 甲醇、Ｃａ（ＮＯ３）２４Ｈ２Ｏ 乙醇、ＣａＣｌ２ 甲醇 水和 ＣａＣｌ２ 乙醇 水（摩尔比分别为 １∶２、１∶２、１∶２∶８、１∶２∶８）处理蚕丝纤维,透析后经冷冻干燥制成固体,利用ＳＤＳ ＰＡＧＥ、电镜扫描和红外光谱对制得的固体进行表征。ＳＤＳ ＰＡＧＥ结果表明：Ｃａ（ＮＯ３）２４Ｈ２Ｏ 醇体系降解丝素蛋白较 ＣａＣｌ２ 醇 水体系降解程度高;电镜扫描的结果表明 Ｃａ（ＮＯ３）２４Ｈ２Ｏ 甲醇和 ＣａＣｌ２ 乙醇 水溶解体系处理的丝素蛋白溶解比较完全,Ｃａ（ＮＯ３）２４Ｈ２Ｏ 甲醇处理的丝素蛋白冻干后为颗粒状,而 ＣａＣｌ２ 乙醇 水处理的丝素蛋白冻干后为片状。红外光谱的结果表明：４种溶液处理后的丝素蛋白构象均介于 β折叠和无规则卷曲之间,从而为丝素蛋白在药物缓释载体领域的应用提供了一定的理论依据。     

不同分娩方式对晚期早产儿肠道菌群的影响

目的 探讨不同分娩方式对晚期早产儿肠道菌群定植的影响。方法 以胎龄（周）为340/7～366/7的15例晚期早产儿为研究对象,根据分娩方式分为自然分娩组（n=8）和剖宫产组（n=7）。收集早产儿出生后3 d、7 d、14 d的粪便标本,应用高通量测序技术对细菌16S rRNA可变区中的V4区进行测序,分析肠道菌群多样性及组成结构。结果 （1）自然分娩组晚期早产儿粪便标本菌群多样性指数逐渐上升,剖宫产组的多样性指数较平稳,两组相比差异无统计学意义;（2）45份粪便标本中共检测出10个菌门,均以变形菌门、厚壁菌门、放线菌门和拟杆菌门为优势菌门,两组晚期早产儿生后变形菌门、拟杆菌门所占比例逐渐降低,厚壁菌门、放线菌门呈增多趋势。两组相比,剖宫产组7 d、14 d时拟杆菌门的相对丰度显著低于自然分娩组（Z=‒2.896,P=0.004;Z=‒2.120,P=0.040）,变形菌门相对丰度仅在7 d时显著高于自然分娩组（Z=‒2.190,P=0.030）;（3）两组研究对象中,除自然分娩组14 d时以双歧杆菌属为优势菌属外,余下均以肠杆菌属为优势菌属。相比于自然分娩组,在7 d时剖宫产组拟杆菌属所占比例显著降低（Z=‒2.806,P=0.005）,肠杆菌属所占比例显著升高（Z=‒2.199,P=0.030）。结论 剖宫产能显著影响婴儿早期肠道菌群的定植,降低肠道中早期拟杆菌的水平。     

Transdermal applications of ethosomes – a detailed review

Skin, the largest organ of the body serves as a potential route of drug delivery for local and systemic effects. However, the outermost layer of skin, the stratum corneum (SC) acts as a tough barrier that prevents penetration of hydrophilic and high molecular weight drugs. Ethosomes are a novel phospholipid vesicular carrier containing high ethanol concentrations and offer improved skin permeability and efficient bioavailability due to their structure and composition. This article gives a review of ethosomes including their compositions, types, mechanism of drug delivery, stability, and safety behaviour. This article also provides a detailed overview of drug delivery applications of ethosomes in various diseases.     

Clostridial neurotoxins as a drug delivery vehicle targeting nervous system

Several neuronal disorders require drug treatment using drug delivery systems for specific delivery of the drugs for the targeted tissues, both at the peripheral and central nervous system levels. We describe a review of information currently available on the potential use of appropriate domains of clostridial neurotoxins, tetanus and botulinum, for effective drug delivery to neuronal systems. While both tetanus and botulinum neurotoxins are capable of delivering drugs the neuronal cells, tetanus neurotoxin is limited in clinical use because of general immunization of population against tetanus. Botulinum neurotoxin which is also being used as a therapeutic reagent has strong potential for drug delivery to nervous tissues.