高喜树碱极具开发价值的拓扑异构酶I抑制剂高喜树碱——极具开发价值的拓扑异构酶I抑制剂

拓扑异构酶Ⅰ(Topo Ⅰ)是细胞生存的必需酶,多种肿瘤细胞中Topo Ⅰ的含量远高于正常细胞,拓扑异构酶Ⅰ抑制剂已成为高选择性抗肿瘤药物研究的一个主攻方向。喜树碱类化合物是最重要的Topo Ⅰ抑制剂,也是世界抗肿瘤药物研究的热点之一。国内外对喜树碱类化合物进行了大量合成和构效关系研究,并从中筛选出了一些具有开发价值的衍生物。其中伊立替康(irinotecan,CPT-11)和拓扑替康     

拓扑异构酶Ⅰ抑制剂研究进展*

拓扑异构酶Ⅰ(topoisomeraseⅠ,TopoⅠ)是抗肿瘤研究的重要靶点,以TopoⅠ为靶点的药物在肿瘤化疗中被广泛应用。目前临床使用或处于临床前研究的拓扑异构酶Ⅰ抑制剂主要分为喜树碱类(camptothecin,CPT)和非喜树碱类(non-camptothecin TopoⅠinhibitor)化合物。本文主要介绍了近年来TopoⅠ抑制剂研发领域的最新进展和发展趋势,并重点就近年来涌现出的一些新的TopoⅠ抑制剂的抗肿瘤活性和药理学特性做一综述。     

高喜树碱--极具开发价值的拓扑异构酶I抑制剂

拓扑异构酶I(Topo I)是细胞生存的必需酶,多种肿瘤细胞中Topo I的含量远高于正常细胞,拓扑异构酶I抑制剂已成为高选择性抗肿瘤药物研究的一个主攻方向.喜树碱类化合物是最重要的Topo I抑制剂,也是世界抗肿瘤药物研究的热点之一.     

拓扑异构酶Ⅰ抑制剂研究进展

拓扑异构酶Ⅰ(topoisomerase,Topo)参与DNA复制、转录、重组、修复等所有关键的细胞核内过程,是抗肿瘤研究的重要靶点,以TopoⅠ为靶点的药物在肿瘤化疗中被广泛应用。目前临床使用或处于临床前研究的拓扑异构酶Ⅰ抑制剂主要分为喜树碱类和非喜树碱类化合物。该文主要介绍了近年来TopoⅠ抑制剂研发领域的最新进展和发展趋势,并就近年来涌现出的一些新的TopoⅠ抑制剂的抗肿瘤活性和药理学特性做一总结。     

拓扑异构酶Ⅰ抑制剂对耐阿霉素淋巴瘤细胞株杀伤和诱导凋亡作用的研究

目的 研究拓扑异构酶Ⅰ抑制剂对耐阿霉素淋巴瘤细胞株(L1210/ADM)的杀伤和诱导凋亡的作用.方法 采用噻唑蓝(MTT法)、钙依赖性磷脂结合蛋白(Annexin V)染色、梯状DNA电泳与细胞形态学观察等方法分析不同浓度(0.05、0.10、0.20、0.40μmol/L)拓扑异构酶Ⅰ抑制剂对L1210/ADM细胞的杀伤和凋亡作用,采用半胱氨酸天冬氨酸蛋白酶(Caspase)8、Caspase-3抑制剂IETD-fmk、DEVD-CHO分析拓扑异构酶Ⅰ抑制剂介导的靶细胞杀伤和凋亡作用与Caspase的关系.结果 0.10 μmol/L拓扑异构酶Ⅰ抑制剂对靶细胞株的杀伤作用,与对照组和0.05 μmol/L组之间差异均有统计学意义(均P＜0.05).加用Caspase酶特异性抑制剂3组各时间点的靶细胞存活率均高于单用拓扑异构酶Ⅰ抑制剂组,差异均有统计学意义(均P＜0.05).靶细胞株经拓扑异构酶Ⅰ抑制剂处理后,部分靶细胞株出现了细胞凋亡;加用Caspase酶特异性抑制剂组中,有部分细胞死亡,但无凋亡小体形成,死亡细胞均为锥虫蓝染色.经拓扑异构酶Ⅰ抑制剂处理的靶细胞株大部分细胞出现胞体解离,并彼此黏附成簇状的、锥虫蓝拒染的凋亡小体,靶细胞株DNA电泳表现为特征性梯状图谱;加入Caspase酶特异性抑制剂的各组可以看到阻断了梯状DNA的产生.结论 拓扑异构酶Ⅰ抑制剂对L1210/ADM细胞株具有较强的杀伤和诱导凋亡作用,其机制可能涉及Caspase-8、Caspase-3的有序性活化.     

DNA拓扑异构酶Ⅰ抑制药--抗肿瘤药喜树碱类衍生物的研究进展

目的：DNA拓扑异构酶Ⅰ是生物体内及其重要的细胞核内酶，参与DNA复制、转录、重组和修复等所有关键的核内过程。该酶已成为重要的抗肿瘤药物研究新靶点。讨论了该酶特异性抑制剂喜树碱类衍生物研究进展。方法：以近年来国内外发表的论文为基础，介绍拓扑异构酶Ⅰ结构、功能研究的最新成果。系统总结了喜树碱类衍生物的构效关系，依据构效关系介绍了最新的结构修饰而得衍生物。结果与结论：将为新型DNA拓扑异构酶Ⅰ抑制剂的合理药物设计打下一定的基础。     

DNA拓扑异构酶Ⅰ抑制剂研究进展

DNA拓扑异构酶Ⅰ（TopoⅠ）参与DNA复制、转录、重组、修复等所有关键的细胞核内过程,已成为极其重要的抗癌药物研究新靶点。目前,美国立意味着研究所药物机制分析电脑网络系统已将TopoⅠ抑制剂为列为重点研究的六大类抗肿瘤药物之一。近年来,TopoⅠ抑制剂研究出现了新的高潮,已有数个喜树碱类化合物进入临床研究,还发现了一些结构新颖、活性较好的非喜树碱类TopoⅠ抑制剂。本文简单介绍TopoⅠ的拓扑结构与活性位点,重点综述了各类TopoⅠ抑制剂研究的最新进展。     

拓扑替康联合用药抗肿瘤研究进展

恶性肿瘤是世界公认的对人类健康危害最为严重的疾病之一,受到学者的极大关注。拓扑替康(topotecan)属喜树碱类,为拓扑异构酶Ⅰ抑制剂,它能导致DNA复制叉断裂,该作用方式使其不易产生耐药性。拓扑替康主要用于卵巢癌和小细胞肺癌的临床治疗,疗效显著。拓扑替康与多种化合物,如顺铂、索拉菲尼、贝伐单抗、氨柔比星、培美曲塞、吉西他滨等联合使用,均具有一定的抗肿瘤增效作用,因此研究联合应用拓扑替康抗肿瘤的课题值得关注。     

喹诺酮化合物研究最新进展——抗肿瘤喹诺酮

喹诺酮化合物研究最新进展抗肿瘤喹诺酮杨玉社赵善荣嵇汝运陈凯先（中国科学院上海药物研究所，上海２０００３１）细菌拓扑异构酶ＩＩ（ＤＮＡ旋转酶）是喹诺酮类抗菌剂细胞内的主要靶酶［１］。最近研究表明，哺乳动物拓扑异构酶ＩＩ是许多重要的抗肿瘤药物细胞内的主要...     

新型6-芳基茚并异喹啉酮衍生物的合成及抗肿瘤活性研究

目的合成一系列新型结构6-芳基茚并异喹啉酮衍生物,并考察目标化合物对DNA拓扑异构酶Ⅰ（TopoⅠ）的抑制活性及其体外抗肿瘤活性。方法以茚和间氯苯甲酸为原料,分别合成高酞酸和4-甲氧基高酞酸;高酞酸通过脱水反应、与亚胺加成反应制得中间体6-芳基茚并异喹啉酮;该中间体与各种氨基取代的氯代物反应得到目标化合物。采用TopoGEN公司的Topoisomerase Ⅰ drug screning kit来测试目标化合物对TopoⅠ的抑制活性;选取人乳腺癌细胞（MCF-7）、非小细胞肺癌细胞（NIH-H460）和人神经胶质瘤细胞（U251）对目标化合物进行体外抗肿瘤活性筛选。结果与结论共合成了17个未见文献报道的新化合物,其结构均经MS（EI）、1H-NMR确证。体外活性筛选结果表明：目标化合物对TopoⅠ表现出良好的抑制作用,且对3种肿瘤细胞表现出较好的抗增殖活性。     

Synthesis, DNA binding, topoisomerase inhibition and cytotoxic properties of 2-chloroethylnitrosourea derivatives of hoechst 33258

A number of novel 2-chloroethylnitrosourea derivatives of Hoechst 33258 were synthesized and examined for cytotoxicity in breast cancer cell cultures and for inhibition of topoisomerases I and II. Evaluation of the cytotoxicity of these compounds employing a MTT assay and inhibition of [3H]thymidine incorporation into DNA in both MDA-MB-231 and MCF-7 breast cancer cells demonstrated that these compounds were more active than Hoechst 33258. The DNA-binding ability of these compounds was evaluated by an ultrafiltration method using calf thymus DNA, poly(dA-dT)2 and poly(dG-dC)2, indicated that these compounds as well as Hoechst 33258 well interact with AT base pair compared with GC pair. Binding studies indicate that these compounds bind more tightly to double-stranded DNA than the parent compound Hoechst 33258. The degree to which these compounds inhibited cell growth breast cancer cells was generally consistent with their relative DNA binding affinity. Mechanistic studies revealed that these compounds act as topoisomerase I (topo I) or topoisomerase II (topo II) inhibitors in plasmid relaxation assays.     

Syntheses and biological activities of rebeccamycin analogues with uncommon sugars

Rebeccamycin analogues containing uncommon sugars and substitutions on the imide nitrogen have been synthesized. Their cytotoxicities were tested in colon cancer and leukemia cells. Their ability to target topoisomerase I was examined using the in vivo complex of the topoisomerase bioassay in Hela cells. Compared with aglycon 1, the modified compounds with various sugar moieties showed more potent cytotoxicities and topo I targeting ability. In addition, the rebeccamycin analogues with various uncommon sugars showed distinct cytotoxicities and topo I targeting activities. The activity of compounds with 2-deoxyglucose (8 and 9) > compounds with 2,6-deoxyglucose (5 and 6) > compounds with 2,3,6-deoxyglucose (10). Furthermore, the anticancer activity of compounds correlated with their ability to target endogenous topo I. These results suggest that the sugar moiety, especially the 2-OH and 6-OH group of the sugar, rather than the modifications in imide structure on the indolocarbazole ring, is a key element for its activity.     

基于KRN7000的结构改造以及它们对自然杀伤T细胞活化作用的构效关系

能够被自然杀伤T细胞所识别的α-半乳糖基神经酰胺具有潜在的治疗肿瘤、感染性疾病和自身免疫性疾病的用途，已引起了研究者们越来越多的注意。人们在寻找具有更好活性的化合物方面取得了不少进展，在理解这些自然杀伤T细胞配体的构效关系方面进行了许多探索。KRN7000是用于自然杀伤T细胞刺激研究的一种主要的糖脂类化合物。本文对近年来基于KRN7000的各种结构改造以及在这些结构改造基础上所获得的构效关系进行详细的综述。     

Syntheses and biological activities of disaccharide daunorubicins

Carbohydrate moiety is found in many anticancer nature products. To explore the carbohydrate moiety of daunorubicin in enhancing anticancer efficacy, several daunorubicin derivatives bearing disaccharide (1-8) have been synthesized. Their cytotoxicities were tested in leukemia K562 and colon cancer SW620 cells. Topoisomerase II (topo II) poisoning was performed with the in vivo complex of topoisomerase bioassay. In both cell lines, compounds with various terminal 2,6-dideoxy sugars (compounds 1, 3, 5, and 8) showed 30- to 60-fold higher anticancer activity than compounds with 2-deoxy- or 6-deoxy sugar (compounds 6 and 7). Compounds with an alpha-linkage between two sugar units (compound 3) showed 35-fold higher anticancer activity than compounds with a beta-linkage (compound 4). In addition, the anticancer activities of these compounds correlated with their ability to target topo II mediated genomic DNA damage in vivo. Compounds 1 and 3 with 2,6-dideoxy sugars produced more covalent topo-DNA complex than compounds with 2-deoxy sugar (6) and 6-deoxy sugar (7). Compounds with an alpha-configuration of terminal 2,6-dideoxy sugar (compounds 1 and 3) showed higher topo II poisoning than their counterparts with the beta-configuration (compounds 2 and 4). These results indicate that sugar moieties in daunorubicin play a significant role in its anticancer activity and topo II inhibition. The second sugar of disaccharide daunorubicin should possess 2,6-dideoxy with alpha-linkage to the first sugar to exhibit better anticancer activity.     

DNA-binding activity and cytotoxicity of Pt-berenil compounds in MDA-MB-231 and MCF-7 breast cancer cells

The compounds of formula [Pt2Cl4(berenil)2]Cl4 and [Pt2Cl2(NH3)2(berenil)2]Cl4 were examined for cytotoxicity in breast cancer cell cultures and for inhibition of topoisomerases I and II. Evaluation of the cytotoxicity of these compounds employing a MTT assay and inhibition of [3H]thymidine incorporation into DNA in both MDA-MB-231 and MCF-7 breast cancer cells demonstrated that these compounds were more active than cisplatin. The DNA-binding ability of these compounds was evaluated by an ultrafiltration method using calf thymus DNA, poly(dA-dT)2 and poly(dG-dC)2, indicated that these compounds show strong specificity for AT base pairs. Binding studies indicate that these compounds bind more tightly to double-stranded DNA than cisplatin. The degree to which these compounds inhibited cell growth breast cancer cells was generally consistent with their relative DNA binding affinity. Mechanistic studies revealed that these compounds act as topoisomerase II (topo II) inhibitors in plasmid relaxation assays.     

Inhibition of topoisomerase I activity and efflux drug transporters’ expression by xanthohumol from hops

Xanthohumol (XN) and its related compounds were evaluated for their cytotoxicity against four different human cancer cell lines, A549 (lung), SK-OV-3 (ovarian), SK-MEL-2 (melanoma), and HCT-15 (colon) using a sulforhodamine B assay. XN showed the most active cytotoxicity against the human cancer cell lines. Isoxanthohumol, 8-prenylnaringenin, and xanthohumol 4'-O-beta-D-glucopyranoside showed comparable cytotoxicity and (2S)-5-methoxy-8-prenylnaringenin 7-O-beta-D-glucopyranoside was the least cytotoxic compound. The anticancer properties of XN, the most active cytotoxic compound, were further investigated. XN showed an inhibitory effect on the activity of DNA topoisomerase I (topo I), which was measured from the relaxation of supercoiled DNA. The inhibition of topo I by XN might explain the cytotoxicity against the human cancer cell lines. Moreover, the expression of the drug efflux genes was investigated to predict the drug resistance. XN clearly decreased the mRNA levels of ABCB1 (MDR1), ABCC1 (MRP1), ABCC2 (MRP2), and ABCC3 (MRP3). These results suggest that XN has anticancer properties by inhibiting the topo I activity and it might be used in conjunction with other anticancer chemotherapeutic agents to reduce the drug resistance inhibiting the efflux drug transporters.     

Evidence from studies with intact mammalian cells that merbarone and bis(dioxopiperazine)s are topoisomerase II poisons

A Chinese hamster V79 cell-based assay for detection of topoisomerase II (topo II) poisons and catalytic inhibitors has been applied to study two bis(dioxopiperazine)s (ICRF-187 and ICRF-154) and a structurally distinct but related compound, merbarone. All three compounds have been previously characterized as being catalytic inhibitors of DNA topo II based primarily on in vitro studies with purified enzymes. The present studies indicate, to the contrary, that all three compounds are very potent DNA clastogens in V79 cells, by virtue of their ability to produce micronuclei, the formation of which is strongly antagonized under conditions in which DNA topo II is rendered catalytically inactive. None of the compounds could be demonstrated to possess catalytic inhibitory activity in intact V79 cells under the conditions tested. These studies provide biological evidence that bis(dioxopiperazine)s are capable of functional topo II poisoning in intact mammalian cells.     

黄酮乙酸类衍生物肿瘤血管破坏剂的设计、合成及其抗肿瘤活性的初步评价

目的设计、合成一系列黄酮乙酸类衍生物肿瘤血管破坏剂,并测定其体外抗肿瘤活性。方法以邻羟基苯乙酮为起始原料,通过氯甲基化、氰基取代、水解以及缩合等反应得到相应的目标化合物;以5,6-二甲基呫吨酮-4-乙酸(DMXAA)为阳性对照药,通过3种模型对目标化合物的抗肿瘤活性进行评价,包括采用Alpha LISA法检测目标化合物对RAW 264.7细胞的促TNF-α分泌作用、采用MTS法测定化合物的细胞毒作用,以及采用鸡胚绒毛尿囊膜模型测定化合物对鸡胚血管生成的影响。结果与结论合成的18个化合物均未见文献报道,其结果经1H-NMR、MS谱确证;活性评价结果表明有3个目标化合物在抗肿瘤测试中表现出较好的体外抗肿瘤活性。     

Evidence from Studies with Intact Mammalian Cells That Merbarone and bis(Dioxopiperazine)s Are Topoisomerase II Poisons

Abstract

A Chinese hamster V79 cell-based assay for detection of topoisomerase II (topo II) poisons and catalytic inhibitors has been applied to study two bis(dioxopiperazine)s (ICRF-187 and ICRF-154) and a structurally distinct but related compound, merbarone. All three compounds have been previously characterized as being catalytic inhibitors of DNA topo II based primarily on in vitro studies with purified enzymes. The present studies indicate, to the contrary, that all three compounds are very potent DNA clastogens in V79 cells, by virtue of their ability to produce micronuclei, the formation of which is strongly antagonized under conditions in which DNA topo II is rendered catalytically inactive. None of the compounds could be demonstrated to possess catalytic inhibitory activity in intact V79 cells under the conditions tested. These studies provide biological evidence that bis(dioxopiperazine)s are capable of functional topo II poisoning in intact mammalian cells.     

Topoisomerase i inhibition and cytotoxicity of licochalcones A and E from<Emphasis Type="Italic">Glycyrrhiza inflata</Emphasis>

Licochalcones A (1) and E (2), retrochalcones or reversely constructed chalcones, isolated from the roots of Glycyrrhiza inflata, were evaluated for their cytotoxicities against four different human tumor cell lines; A549 (lung), SK-OV-3 (ovarian), SK-MEL-2 (melanoma) and HCT-15 (colon), using the sulforhodamine B (SRB) assay. The effects of these compounds toward the DNA topoisomerase I (topo I) inhibitory activity were also measured using the supercoiled DNA unwinding assay. All compounds showed moderate cytotoxicities against the four different human tumor cell lines and inhibited the topo I activity in dose-dependent manners. The inhibition of topo I by licochalcones A (1) and E (2) may explain the cytotoxicities of these compounds against the human tumor cell lines.