Ⅰ型核糖体失活蛋白（RIPs）抗肿瘤作用的研究进展

目的介绍Ⅰ型核糖体失活蛋白抗肿瘤作用的研究概况及展望。方法总结核糖体失活蛋白抗肿瘤作用及机制。结果Ⅰ型核糖体失活蛋白具有明显的抗肿瘤作用。结论Ⅰ型核糖体失活蛋白是很有发展前景的抗肿瘤植物药。     

麻疯树核糖体失活蛋白抗肿瘤作用

目的：研究麻疯树核糖体失活蛋白的抗肿瘤作用。方法：抗肿瘤活性、N-糖苷酶活性和蛋白合成抑制活性分别用MTT法、苯胺裂解法和兔网织红细胞系统测定;用计算机软件分析比较麻疯树核糖体失活蛋白N-糖苷酶的活性结构域。结果：麻疯树核糖体失活蛋白具有抑制胃癌细胞（SGC-7901）,小鼠骨髓瘤细胞（Sp2/0),人肝癌细胞体外增殖的能力,其IC50值分别为0.23(0.15-0.32)mg/L,0.66(0.35-0.97)mg/L和3.16（2.74-3.58)mg/L,但对Hela细胞和正常细胞（MRC）无抑制作用。结论：麻疯树核糖体失活蛋白具有较强的抗肿瘤活性,其作用机制与其具有的N-糖苷酶活性相关。     

核糖体失活蛋白抗血液病肿瘤的研究

核糖体失活蛋白是广泛存在于高等植物中能抑制核糖体翻译功能的一类毒蛋白。它能够对哺乳动物拔糖体大亚基上的28SrRNA进行脱嘌呤作用。从而破坏技糖体的结构。抑制蛋白质的生物合成。本文就核糖体失活蛋白的生物学活性以及近年来在抗血液病肿瘤方面的研究进展做一综述。     

Promotion of ATP and S-140 to ribosome inactivation with camphorin,cinnamomin,and other RNA N-glycosidases

目的：研究ＡＴＰ和Ｓ１４０对Ⅰ型和Ⅱ型核糖体失活蛋白（ＲＩＰ）失活核糖体的影响．方法：采用凝胶电泳分析特征ＲＩＰ作用片断（Ｒ片断），以及改进的二步法标记苯丙氨酸外源ｐｏｌｙ（Ｕ）翻译体系，定量检测外加因子对ＲＩＰ失活核糖体作用的影响．结果：ＡＴＰ和Ｓ１４０对所有用于检测的Ⅰ型和Ⅱ型ＲＩＰ失活核糖体的功能均表现出不同程度的促进作用．对于Ⅰ型ＲＩＰ中克木毒蛋白、天花粉毒蛋白、γ苦瓜子毒蛋白、丝瓜毒蛋白Ａ、丝瓜毒蛋白Ｓ和Ⅱ型ＲＩＰ中蓖麻毒蛋白、蓖麻毒蛋白Ａ链；辛纳毒蛋白、辛纳毒蛋白Ａ链，ＩＣ５０增强活性比率分别为３１０８，１５，１５１，４５，５１和４７，７，２６，１２．结论：首次发现ＡＴＰ和Ｓ１４０对Ⅱ型ＲＩＰ及其Ａ链具有活性增强作用．克木毒蛋白和辛纳毒蛋白在对ＡＴＰ和Ｓ１４０的辅助需求方面有显著区别     

天花粉蛋白对人宫颈癌HeLa细胞增殖和细胞调亡的影响

天花粉蛋白(Trichosanthin,TCS)是从葫芦科植物栝(蒌)的块根中提取出来的一种单链核糖体失活蛋白(ribosome-in-activating protein,RIP),主要引发中期流产,抑制爱滋病病毒(HIV)增殖,调节人体免疫功能等多方面的作用[1].     

苦瓜籽核糖体失活蛋白的分离纯化及抗氧化活性的研究

目的改进苦瓜籽核糖体失活蛋白的提取工艺 ,并对其抗氧化活性进行研究。方法苦瓜籽经粉碎 ,50mmol/L乙酸抽提 ,硫酸铵沉淀 ,经阳离子交换及凝胶柱色谱等步骤进一步纯化后 ,测定所得两种核糖体失活蛋白的理化性质。结果纯化后得到一种分子量为 2 9.6kD的蛋白质和一种小分子量蛋白质 ,两者在无细胞系统中抑制50 %蛋白质合成浓度分别为 4 .3× 1 0 - 6 、1 .4× 1 0 - 6 mol/L ,含糖量分别为 4 .83 %、1 .82 % ,类超氧化物歧化酶 (SOD)活性分别为 79.0 5、1 7.2 5u/mg。阳性对照纯品SOD活性为 1 2 67u/mg。结论从苦瓜籽中分离纯化出两种不同分子量的核糖体失活蛋白均为糖蛋白质 ,且具有一定的抗氧化活性     

蓖麻毒素的毒性作用机制及其在肿瘤治疗中的应用

蓖麻毒素对哺乳动物细胞具有很强的毒性,属于Ⅱ型核糖体失活蛋白。其A链是活性链,可使核糖体失活,从而使蛋白质合成受阻,细胞死亡。基于蓖麻毒素的细胞毒性,人们将蓖麻毒素及其A链应用于肿瘤治疗领域,目的在于特异性杀伤肿瘤细胞,并减小对正常细胞的毒性。本文就蓖麻毒素的分子结构、毒性机制以及近年来在肿瘤治疗领域的研究进展作一综述。     

聚乙二醇修饰对仅α-苦瓜素抗肿瘤活性的影响

目的 探讨苦瓜籽核糖体失活蛋白α-苦瓜素(α-MMC)经聚乙二醇(PEG)修饰后,其体外细胞毒性和体内抗肿瘤活性的变化.方法 用MTT法测定α-MMC和PEG-α-MMC结合物对小鼠乳腺癌细胞EMT-6的抑制率;通过BALB/C小鼠模型研究药物对EMT-6细胞嫁接瘤生长的抑制作用.结果 在相同的条件下,PEG-α-MM...     

病原菌对抗菌药物的耐药机制

细菌通过抗菌药作用靶位的改变，抗菌药的失活或改变，抗菌药的外排或细菌细胞通透性的改变，而产生耐药机制。β－内酰胺类抗生素的作用靶青霉素结合蛋白、喹诺酮类药物的作用靶DNA促旋酶和拓扑异构酶Ⅳ的突变可以分别导致β－内酰胺和喹诺酮类耐药性；四环素类、氨基糖苷类抗生素与核糖体30S亚基结合，大环内酯类、林可酰胺类、链阳菌素B（MLSB）与核糖体50S亚基结合，抑制细菌蛋白质的合成，当产生核糖体保护蛋白、16S rRNA或核糖体蛋白S12突变、23S rRNA突变时，会影响抗菌药与核糖体的结合，分别导致四环素耐药性、氨基糖苷耐药性和MLSB耐药性；糖肽类抗生素作用靶位肽聚糖前体末端的改变，导致糖肽耐药性。产生破坏β－内酰胺环的β－内酰胺酶、氨基糖苷修饰酶（乙酰转移酶，磷酸转移酶，核苷酸转移酶）、MLSB修饰酶（酯酶，磷酸转移酶，乙酰转移酶，核苷酸转移酶）可以分别导致相应的抗生素失活，而产生耐药性。外排泵系统的存在可以降低细菌细胞内的药物浓度，是导致多重耐药性的重要机制。细菌细胞通透性的改变，使抗菌药不能有效进入细菌细胞，也是耐药机制之一。     

天花粉蛋白的研究进展

天花粉蛋白(trichosanthin,TCS)是从葫芦科栝楼属植物栝楼的根块中提取出来的一种碱性蛋白,属于Ⅰ型核糖体失活蛋白(RibosomeInactivating Proteins,RIPs).它与双链RIPs-蓖麻毒蛋白(Ricin)的A链在一级结构上有56%的同源性.     

小檗碱抗肿瘤研究进展

目的 介绍小檗碱抗肿瘤作用的研究概况及展望。方法 总结小檗碱的抗肿瘤活性及机制。结果 小檗碱具有明显的抗肿瘤作用。结论 小檗碱是有发展前景的抗肿瘤药。     

The structure of ribosome inactivating proteins

Ribosome Inactivating Proteins, RIPs, depurinate an invariant adenine from the 28S rRNA of eukaryotic ribosomes; they have evolved to near enzymatic perfection for this task. The N-glycosidase fold is conserved in plant and bacterial enzymes. RIPs can form complexes with cell surface recognition proteins that dramatically increase the cytotoxicity of the molecule.     

Antitumour bioactive peptides isolated from marine organisms

Marine organisms are an important source of antitumour active substances. Thus, pharmaceutical research in recent years has focused on exploring new antitumour drugs derived from marine organisms, and, many peptide drugs with strong antitumour activities have been successfully extracted. Based on different mechanisms, this paper reviews the research on several typical antitumour bioactive peptides in marine drugs and the latest progress therein. Additionally, the development prospects for these antitumour bioactive peptide‐based drugs are discussed so as to provide a reference for future research in this field.     

Antitumour activity of Angelica archangelica leaf extract

BACKGROUND: The purpose of this study was to examine the effect of a leaf extract from A. archangelica on the growth of Crl mouse breast cancer cells in vitro and in vivo. Materials and METHODS: The antiproliferative activity of the extract was measured by 3H-thymidine uptake in the Crl cells in vitro. Twenty mice were injected with the Crl cells, and 11 of them were fed A. archangelica leaf extract, and the progress of the tumours was followed. RESULTS: The leaf extract was mildly antiproliferative on the Crl cells with an EC50 of 87.6 microg/ml The antitumour activity of the extract was expressed in the mice by marked reduction in tumour growth. In the experimental animals, 9 out of 11 mice developed no or very small tumours, whereas control animals, not receiving the extract, developed significantly larger tumours (p<0.01), as estimated by Mann-Whitney U-test. The antitumour activity of the leaf extract could not be explained by the antiproliferative activity of furanocoumarins present in the extract. CONCLUSION: The results demonstrate the antiproliferative activity in vitro and antitumour activity in vivo of a leaf extract from A. archangelica     

The genetics and properties of cereal ribosome-inactivating proteins

Plants contain proteins that are capable of inactivating ribosomes, commonly referred to as Ribosome Inactivating Proteins (RIPs). These particular plant proteins have received attention in biological and biomedical research because of their unique biological activities towards animals and human cells as cell-killing agents. Some of the best-characterised RIPs have been isolated from exotic plants, but they have also been found in cereals and other food crops. Cereals contain, in general, RIPs in the endosperm protein pool: they share a high similarity with all the other RIPs retaining, however, characteristic features forming a distinct class which diversified significantly during evolution. They appear to be involved in quite different physiological roles, such as defence against pathogens and/or involved in regulatory and developmental processes. This review aims to provide a critical assessment to work related to cereal RIP with particular emphasis to the maize RIPs.     

乳清提取物对小鼠免疫功能影响及抗癌作用的初步研究

目的观察豆乳清中活性物质对小鼠免疫功能的影响及抗癌活性。方法乳清活性物质经灌胃或腹腔注射给药后 ,测定各组小鼠的胸腺指数、脾指数、巨噬细胞吞噬功能及抗癌效应。结果灌胃给药一定剂量可明显增加小鼠胸腺和脾指数 (P <0 .0 1 ) ,与对照组比较其吞噬百分率、吞噬指数差异显著 (P <0 .0 1 ) ;腹腔注射给药对荷U1 4肿瘤和荷HepA肿瘤小鼠的肿瘤生长有一定的抑制作用 ,抑瘤率以HepA更为显著。结论乳清活性物质具有一定的免疫增强功能和抗癌效应     

南蛇藤属植物化学成分及活性研究进展

南蛇藤属植物在我国分布广泛，近年来从中分得了多种β-二氢沉香呋喃型倍半萜和friedlane等型三萜，其中一些具有昆虫拒食、抗肿瘤和细胞毒活性。本文综述了近10年来从南蛇藤属植物中分得的化学成分及其活性的研究进展。     

American Association for Cancer Research 1997: progress and new hope in the fight against cancer

Considerable progress has been made with tyrosine kinase inhibitors. After long and sustained efforts, several tyrosine kinase inhibitors with convincing in vivo experimental antitumour properties such as CP-358,774, ZD 1839, CEP-751 are entering Phase I clinical trials. Significant in vivo experimental antitumour activity has also been described for two new families of farnesyl transferase inhibitors (SCH 59228 and PD 083176 series). Novel inhibitors of tubulin polymerisation are on the verge of entering clinical trials. These include F12458, an analogue of vinorelbine, and C52/C55 cryptophycin derivatives.