Combretastatin A-4(CA-4)是一个天然的秋水仙碱结合位点的微管蛋白抑制剂,具有抗肿瘤活性。PI3K信号通路是细胞内重要的信号转导通路之一,也是癌细胞中常见的异常表达信号通路。微管蛋白抑制剂和信号通路激酶抑制剂均为抗肿瘤药物研发...Combretastatin A-4(CA-4)是一个天然的秋水仙碱结合位点的微管蛋白抑制剂,具有抗肿瘤活性。PI3K信号通路是细胞内重要的信号转导通路之一,也是癌细胞中常见的异常表达信号通路。微管蛋白抑制剂和信号通路激酶抑制剂均为抗肿瘤药物研发的热点。设计、筛选并合成了具有秋水仙碱和PI3K双靶点的CA-4衍生物。利用SBDD技术,采用活性基团协作的方法,对CA-4进行秋水仙碱和PI3K双靶点结构改造。结合CA-4的构效关系,保留A环及3个甲氧基,以羰基取代连接双键碳以保证顺式构型,苯并呋喃环取代B环,B环侧链引入卤素增效,依据结合活性自由能打分值筛选出9种靶点活性高的衍生物进行分子对接分析及可视化分析,并通过碘代、溴代、Rap-Stoermer偶联反应和Heck偶联反应合成目标化合物CA-4,其结构经1 H NMR、13 C NMR和MS确证。活性测试结果表明:目标化合物对乳腺癌MCF-7和MDA-MB-2312种肿瘤细胞具有抑制作用。展开更多
The paper states the characteristics and basic market positioning of WiMAX. It should be noted that WiMax is a new generation WMAN (Wideband MAN) broadband wireless access standard with good forward extensibility. It ...The paper states the characteristics and basic market positioning of WiMAX. It should be noted that WiMax is a new generation WMAN (Wideband MAN) broadband wireless access standard with good forward extensibility. It is emphasized that the basic market positioning of WiMAX should be nothing but WMAN applications. It is predicted that the applications of WiMax would face severe challenges mainly due to its high cost, at least at the initial stage. Finally the paper gives all-around analysis on the relationship between Wi-Fi, WiMAX, WBMA, 3G, 3G+ and 4G.展开更多
To investigate the relationship between tendinopathy and higher production of prostaglandins E2 (PGE2) and leukotriene B4(LTB4) induced by cyclic stretching of human patellar tendon fibroblasts.Methods We used a novel...To investigate the relationship between tendinopathy and higher production of prostaglandins E2 (PGE2) and leukotriene B4(LTB4) induced by cyclic stretching of human patellar tendon fibroblasts.Methods We used a novel in vitro model system to mimic in vivo conditions,where human patellar tendon fibroblasts (HPTFs) were uniaxially stretched with different magnitudes of stretching (4%,8% and 12%).Non-stretched fibroblasts were used as control.The productions of PGE2 and LTB4 as well as the expression of cycloxygenase (COX) and 5-lipoxygenase (5-LO) were then measured every four hours of cyclic stretching.In addition,we treated the cells with inhibitors of COX or 5-LO.Results It was found that cyclic stretching of fibroblasts at 8% and 12% of stretching increased PGE2 and LTB4 levels.Blocking the COX enzyme with indomethacin (25 mol/L) decreased PGE2 levels but increased LTB4 production and vice versa.Whereas decreasing LTB4 production with MK-886 (10 μmol/L) could increase PGE2 levels compared to cells tretched without inhibitors.Conclusion Cyclic stretching of HPTFs produces high levels of PGE2 and LTB4,where a balance exists:blocking PGE2 production increases the production of LTB4,and vice versa.Therefore,this study raises the possibility that the routine use of COX inhibitors in clinical treatment of tendinopathy may exacerbate the condition by causing neutrophil-mediated inflammatory and degenerative changes in the tendon due to increased levels of LTB4,which is a potent chemoattractant for neutrophils.17 refs,3 figs.展开更多
文摘Combretastatin A-4(CA-4)是一个天然的秋水仙碱结合位点的微管蛋白抑制剂,具有抗肿瘤活性。PI3K信号通路是细胞内重要的信号转导通路之一,也是癌细胞中常见的异常表达信号通路。微管蛋白抑制剂和信号通路激酶抑制剂均为抗肿瘤药物研发的热点。设计、筛选并合成了具有秋水仙碱和PI3K双靶点的CA-4衍生物。利用SBDD技术,采用活性基团协作的方法,对CA-4进行秋水仙碱和PI3K双靶点结构改造。结合CA-4的构效关系,保留A环及3个甲氧基,以羰基取代连接双键碳以保证顺式构型,苯并呋喃环取代B环,B环侧链引入卤素增效,依据结合活性自由能打分值筛选出9种靶点活性高的衍生物进行分子对接分析及可视化分析,并通过碘代、溴代、Rap-Stoermer偶联反应和Heck偶联反应合成目标化合物CA-4,其结构经1 H NMR、13 C NMR和MS确证。活性测试结果表明:目标化合物对乳腺癌MCF-7和MDA-MB-2312种肿瘤细胞具有抑制作用。
文摘The paper states the characteristics and basic market positioning of WiMAX. It should be noted that WiMax is a new generation WMAN (Wideband MAN) broadband wireless access standard with good forward extensibility. It is emphasized that the basic market positioning of WiMAX should be nothing but WMAN applications. It is predicted that the applications of WiMax would face severe challenges mainly due to its high cost, at least at the initial stage. Finally the paper gives all-around analysis on the relationship between Wi-Fi, WiMAX, WBMA, 3G, 3G+ and 4G.
文摘To investigate the relationship between tendinopathy and higher production of prostaglandins E2 (PGE2) and leukotriene B4(LTB4) induced by cyclic stretching of human patellar tendon fibroblasts.Methods We used a novel in vitro model system to mimic in vivo conditions,where human patellar tendon fibroblasts (HPTFs) were uniaxially stretched with different magnitudes of stretching (4%,8% and 12%).Non-stretched fibroblasts were used as control.The productions of PGE2 and LTB4 as well as the expression of cycloxygenase (COX) and 5-lipoxygenase (5-LO) were then measured every four hours of cyclic stretching.In addition,we treated the cells with inhibitors of COX or 5-LO.Results It was found that cyclic stretching of fibroblasts at 8% and 12% of stretching increased PGE2 and LTB4 levels.Blocking the COX enzyme with indomethacin (25 mol/L) decreased PGE2 levels but increased LTB4 production and vice versa.Whereas decreasing LTB4 production with MK-886 (10 μmol/L) could increase PGE2 levels compared to cells tretched without inhibitors.Conclusion Cyclic stretching of HPTFs produces high levels of PGE2 and LTB4,where a balance exists:blocking PGE2 production increases the production of LTB4,and vice versa.Therefore,this study raises the possibility that the routine use of COX inhibitors in clinical treatment of tendinopathy may exacerbate the condition by causing neutrophil-mediated inflammatory and degenerative changes in the tendon due to increased levels of LTB4,which is a potent chemoattractant for neutrophils.17 refs,3 figs.
基金National Natural Science Foundation of China(30640048)the Science Foundation of the Key Laboratory of Biotic Environment andEcological Safetyin Anhui Province, China
