PHEA-MTXgNPHEA-SUC-MTX的合成与表征

背景：在大分子药物的设计中,往往需要在载体与药物之间引入新的基团,即连接基。选择合适的连接基,可以控制药物在体内的释放形式和释放速率。目的：制备和表征一种新的大分子靶向抗肿瘤药物。设计、时间及地点：观察实验,于2007—06／2008—11在南京大学生命科学院医药生物技术国家重点实验室完成。材料：L-天冬氨酸,无水N,N-二甲基甲酰胺,BOP试剂购自美国Sigma公司,其余均为国产试剂。甲氨蝶呤由连云港恒瑞制药有限公司赠送。方法：实验把甲氨喋呤与PHEA和PHEA．SUC偶联,制备琥珀酰化的α, β-聚（2-羟乙基）-D,L-天冬酰胺-甲氨喋呤（PHEA-SUC-MTX）和α, β-聚-（2-羟乙基）-D,L-天冬酰胺-甲氨喋呤（PHEA—MTX）。主要观察指标：采用红外图谱、核磁共振、元素分析方法检测大分子靶向药物的结构,紫外分光光度法测定PHEA-Suc—MTX和PHEA．MTX中甲氨喋呤的含量。结果：PHEA．MTX和PHEA．SUC—MTX的结构通过红外光谱和核磁共振分析确认。甲氨喋呤与PHEA及PHEA-suc共价偶联,其甲氨喋呤含量分别为5．80％及5．86％。结论：合成的大分子靶向药物PHEA．MTX、PHEA．SUC．MTX结构稳定。     

聚天冬酰胺衍生物载体（PHEA-Suc和Gal-PHEA-Suc）的合成、表征和体外试验

背景：寻找一种新的大分子作为靶向药物载体。 目的：制备一种新型聚天冬酰胺衍生物——琥珀酰化的α，β-聚-（2-羟乙基）-D，L-天冬酰胺（PHEA-Suc）和半乳糖基化的琥珀酰化的α，β-聚-（2-羟乙基）-D，L-天冬酰胺（Gal-PHEA-Suc），对材料进行了表征，体外观察其细胞毒性。 设计、时间及地点：体外观察实验，于2005-06／2007-06在南京大学生命科学院医药生物技术国家重点实验室完成。 材料：L-天冬氨酸，无水N，N-二甲基甲酰胺，乳糖酸，异硫氰酸荧光素，二甲亚砜，MTT购自美国Sigma公司；人宫颈癌细胞系HeLa和肝癌细胞系HepG2均购自上海细胞所细胞库；新生牛血清购自杭州四季青生物公司；胰蛋白酶购自美国Hyclone公司；其余试剂均为国产分析纯。 方法：采用红外图谱、核磁共振、元素分析、分子量测定等方法对材料进行了表征，通过四唑盐比色法测定PHEA，SUC和Gal-PHEA-SUC的细胞毒性。 主要观察指标：聚天冬酰胺衍生物载体的结构及细胞毒性。 结果：PHEA-SUC和Gal-PHEA-SUC的结构通过红外光谱和核磁共振分析确认。由元素分析算得PHEA-SUC和Gal-PHEA-SUC的琥珀酰化度为43％（mol／mol），Gal-PHEA-suc的半乳糖基化度为7．6％（mol／mol）。PHEA—SUC和Gal-PHEA—suc的体外细胞毒性分析表明，它们对HeLa和HepG2细胞生长的抑制作用很小，在浓度低于500mg／L时没有抑制作用。 结论：聚天冬酰胺衍生物PHEA-suc、Gal-PHEA-suc细胞毒性低，且具有-suc活性基团和-gal靶向基团，可以作为理想的靶向药物载体。     

聚天冬酰胺衍生物载体(PHEA-Suc 和Gal-PHEA-Suc)的合成、表征和体外试验

背景：寻找一种新的大分子作为靶向药物载体。 目的：制备一种新型聚天冬酰胺衍生物——琥珀酰化的α，β-聚-（2-羟乙基）-D，L-天冬酰胺（PHEA-Suc）和半乳糖基化的琥珀酰化的α，β-聚-（2-羟乙基）-D，L-天冬酰胺（Gal-PHEA-Suc），对材料进行了表征，体外观察其细胞毒性。 设计、时间及地点：体外观察实验，于2005-06／2007-06在南京大学生命科学院医药生物技术国家重点实验室完成。 材料：L-天冬氨酸，无水N，N-二甲基甲酰胺，乳糖酸，异硫氰酸荧光素，二甲亚砜，MTT购自美国Sigma公司；人宫颈癌细胞系HeLa和肝癌细胞系HepG2均购自上海细胞所细胞库；新生牛血清购自杭州四季青生物公司；胰蛋白酶购自美国Hyclone公司；其余试剂均为国产分析纯。 方法：采用红外图谱、核磁共振、元素分析、分子量测定等方法对材料进行了表征，通过四唑盐比色法测定PHEA，SUC和Gal-PHEA-SUC的细胞毒性。 主要观察指标：聚天冬酰胺衍生物载体的结构及细胞毒性。 结果：PHEA-SUC和Gal-PHEA-SUC的结构通过红外光谱和核磁共振分析确认。由元素分析算得PHEA-SUC和Gal-PHEA-SUC的琥珀酰化度为43％（mol／mol），Gal-PHEA-suc的半乳糖基化度为7．6％（mol／mol）。PHEA—SUC和Gal-PHEA—suc的体外细胞毒性分析表明，它们对HeLa和HepG2细胞生长的抑制作用很小，在浓度低于500mg／L时没有抑制作用。 结论：聚天冬酰胺衍生物PHEA-suc、Gal-PHEA-suc细胞毒性低，且具有-suc活性基团和-gal靶向基团，可以作为理想的靶向药物载体。     

羧甲基壳聚糖/羟乙基纤维素共混凝胶的制备及性能

将羟乙基纤维素和羧甲基壳聚糖通过戊二醛交联制备羧甲基壳聚糖,羟乙基纤维素凝胶,考察不同质量比的共混凝胶在不同pH缓冲液中的溶胀和释药性能.在溶胀性能研究中,pH值为1.0时凝胶的溶胀度小于pH值为3,5,7时.在羧甲基壳聚糖:羟乙基纤维素为5:5时,其最大溶胀度可以达到4.2左右,相比其他质量比共混体系,其溶胀效果明显增强.各种释放条件下,单纯羧甲基壳聚糖的交联体系,牛血清蛋白释放速度最大,随着羟乙基纤维素比例的增加,牛血清蛋白的药物释放速度变快,释放量在逐渐变大,pH=1.0时,羧甲基壳聚糖:羟乙基纤维素为7:3,药物释放百分比为60%;而羧甲基壳聚糖:羟乙基纤维素为5:5时,药物释放百分比约为80%左右.说明羧甲基壳聚糖,羟乙基纤维素共混凝胶适合于胃部滞留给药.     

米非司酮联合甲氨喋呤治疗异位妊娠的疗效观察

目的:探讨米非司酮联合甲氨喋呤治疗异位妊娠的疗效观察.方法:米非司酮联合甲氨喋呤及米非司酮联合甲氨喋呤单次肌肉注射与对照组单用米非司酮比较.结果:米非司酮联合甲氨喋呤治疗效果明显优于单用米非司酮组.结论:对早期异位妊娠患者,米非司酮联合甲氨喋呤治疗是一种较理想的药物保守治疗方式.     

米非司酮联合甲氨喋呤治疗异位妊娠的疗效观察

目的 观察米非司酮联合甲氨喋呤治疗异位妊娠的疗效.方法 治疗给予甲氨喋呤单次肌肉注射并口服米非司酮,对照组给予甲氨喋呤单次肌内注射,监测血β-人绒毛膜促性腺激素(β-HCG)水平及B超等情况,并观察不良反应.结果 治疗组治愈率为90.0%,对照组治愈率为63.3%,治疗组疗效高于对照组(P＜0.01).两组不良反应差异无显著性(P＞0.05).结论 米非司酮联合甲氨喋呤治疗异位妊娠疗效显著.     

肝靶向性壳聚糖基纳米载药体系的研究与应用

目的:阐述肝靶向性壳聚糖基纳米载药体系的研究和应用.方法:采用电子检索的方式,在万方数据库中检索2002-12/2010-02有关肝靶向性壳聚糖基纳米的研究文章,关键词为"壳聚糖基纳米载药体系,肝靶向性,研究,应用".排除重复研究、普通综述或Meta分析类文章,筛选纳入18篇文献进行阐述.结果:壳聚糖纳米粒是一种天然无毒的非病毒药物载体,有良好的生物相容性和生物可降解性,可提高药物的稳定性,可靶向释放药物,增加药物的吸收等,达到控释和靶向治疗的作用.载药壳聚糖纳米粒的制备有离子交联法、沉淀法、超声乳化法、反相微乳法、静电纺丝法、反相悬浮交联法、逆相蒸发一短时超声法、还原胺化法等8种不同方法.用于肝脏组织工程如肝移植、人工肝,能维持和提高肝细胞活性和功能,有利于肝细胞生长;肝脏肿瘤治疗中使药物靶向释放于肿瘤部位,更有效抑制肿瘤细胞、降低毒副作用等.结论:肝靶向性壳聚糖基纳米载药体系是一种安全、高效的靶向性基因载体,但它的研究还需不断深入.     

抗菌肽Cecropin A基因原核表达及表达产物的鉴定

背景:Cecropins是一种具有抗菌活性的小分子蛋白质.采用真核细胞表达或人工合成Cecropins,效率低、成本高.目的:克隆表达家蝇抗菌肽基因Cecropin A,并对其重组表达产物进行鉴定.方法:依据GenBank中家蝇Cecropin A基因序列设计特异性引物,用RT-PCR从家蝇幼虫组织中扩增Cecropin A成熟肽基因,将其克隆入原核表达载体pET32a中,与表达载体中的Thioredoxin基因构成融合基因,并转化E.coli BL21.经异丙基-β-D硫代半乳糖苷诱导表达.采用家蝇幼虫血淋巴免疫家兔获得抗血清;Western blot和三羟甲基氨基甘氨酸-十二烷基硫酸钠-聚丙烯酰胺凝胶电泳鉴定诱导的重组蛋白质.结果与结论:经异丙基-β-D硫代半乳糖苷诱导,E.coli BL21可表达Cecropin A成熟肽,兔抗家蝇幼虫血清、三羟甲基氨基甘氨酸-十二烷基硫酸钠-聚丙烯酰胺凝胶电泳及Western blot结果证实表达产物为Cecropin A成熟肽.说明使用原核表达系统可以获得天然Cecropin A成熟肽.     

整合素αvβ3受体靶向载药脂质体的制备及体外靶向性

背景:含RGD序列的多肽是多种整合素的识别位点,以其相对分子质量小、稳定、易于制备,且无免疫原性等优点被广泛用于纳米靶向药物传递系统的设计.目的:制备以RGD环五肽为配基的整合素αvβ3载药脂质体,通过体外细胞学实验证实其受体靶向性.方法:使用人工合成的RGD环五肽作为靶向分子探针,通过高压均质法制备靶向整合素αvβ3载药脂质体,采用扫描电镜和激光粒度分析仪检测纳米颗粒形态和粒径;以流式细胞分析观察其对血管平滑肌细胞的特异性标记,并考察荷载药物的离体缓释能力以及体外靶向能力.结果与结论:合成的靶向载药脂质体粒径为(175±6) nm,包封率为(96.33±1.02)%,体外溶出时间超过5 d.靶向载药脂质体对整合素αvβ3具有较高的特异性亲和力,可通过受体介导的内吞作用进入细胞内.提示制备的靶向整合素αvβ3载药脂质体,具有较高的药物包封率及缓释性,能与整合素αvβ3受体特异性结合,是一种新型的受体介导靶向制剂.     

《中国实用护理杂志》2006年第11A期继续医学教育试题答题卡(多选题)

多选题(仔细阅读“继续医学教育园地”栏目的文章,即可找到答案)试题:1.临床应用的抗代谢的药物有哪些?A.氟脲嘧啶B.6-巯嘌呤C.甲氨喋呤D.顺铂2.易引起口腔溃疡的化疗药物有:A.氟脲嘧啶B.6-巯嘌呤C.甲氨喋呤D.阿霉素3.口炎制剂是选用哪几种药物配制的?A.止痛类B.激素类C.抗生素     

alpha,beta-poly(asparthylhydrazide)-glycidyltrimethylammonium chloride copolymers (PAHy-GTA): novel polymers with potential for DNA delivery.

Hydrophilic polycations form complexes when mixed with plasmids. Following functionalisation with glycidyltrimethylammonium chloride (GTA) alpha,beta-poly(asparthylhydrazide) (PAHy), a water-soluble synthetic macromolecule, becomes polycationic and potentially useful for systemic gene delivery. Initially the biocompatibility of PAHy and PAHy-GTA derivatives with different degrees of positive charge substitution were studied and it was shown that PAHy-GTA was neither haemolytic nor cytotoxicity up to 1 mg/ml. After intravenous injection (125)I-labelled PAHy-GTA derivative containing 46 mol% (PAHy-GTA(b)) of trimethylammonium groups did not accumulate in the liver (4.1+/-0.9% of the recovered dose after 1 h) but was subjected to renal excretion (45+/-21% of the recovered dose was in the kidneys after 1 h). PAHy-GTA formed complexes with DNA (gel retardation) and they protected against degradation by DNase II. Finally the ability of the PAHy-GTA(b) derivative to mediate the transfection of HepG2 cells using the marker gene beta-galactosidase was studied. The optimum plasmid/polymer mass ratio was examined in comparison to LipofectACE, Lipofectin and polyethylenimine.     

Pharmacology of (2S,4Z)-N-[(2S)-2-hydroxy-2-phenylethyl]-4-(methoxyimino) -1-[(2'-methyl[1,1'-biphenyl]-4-yl)carbonyl]-2-pyrrolidinecarboxamide,a new potent and selective nonpeptide antagonist of the oxytocin receptor

We have discovered a new, potent, selective, and orally active oxytocin receptor antagonist, (2S,4Z)-N-[(2S)-2-hydroxy-2-phenylethyl]-4-(methoxyimino)-1-[(2'-methyl[1,1'-biphenyl]-4-yl)carbonyl]-2-pyrrolidinecarboxamide (compound 1). We report the biochemical, pharmacological, and pharmacokinetic characterization in vitro and in vivo of this compound. Compound 1 competitively inhibits binding of [3H]oxytocin and the peptide antagonist 125I-ornithine vasotocin analog to human and rat oxytocin receptor expressed in human embryonic kidney 293-EBNA or Chinese hamster ovary cells with nanomolar potency. Selectivity against vasopressin receptor subtypes is >6-fold for V1a and >350-fold for V2 and V1b. Compound 1 inhibits oxytocin-evoked intracellular Ca2+ mobilization (IC50 = 8 nM). Compound 1 has no intrinsic agonist activity at the oxytocin receptor. Oxytocininduced contraction of isolated rat uterine strips is blocked by compound 1 (pA2 = 7.82). In anesthetized nonpregnant rats, single administration of compound 1 by i.v. or oral routes causes dose-dependent inhibition of contractions elicited by repeated injections of oxytocin with ED50 = 3.5 mg/kg i.v. and 89 mg/kg p.o., respectively. Compound 1 significantly inhibits spontaneous uterine contractions in pregnant rats near term when administered intravenously or orally. We conclude that compound 1 is a potent, selective, and orally active nonpeptide oxytocin receptor antagonist, which is a suitable candidate for evaluation as a potential tocolytic agent for the management of preterm labor.     

Bupropion inhibits nicotine-evoked [(3)H]overflow from rat striatal slices preloaded with [(3)H]dopamine and from rat hippocampal slices preloaded with [(3)H]norepinephrine

Bupropion, an efficacious antidepressant and smoking cessation agent, inhibits dopamine and norepinephrine transporters (DAT and NET, respectively). Recently, bupropion has been reported to noncompetitively inhibit alpha3beta2, alpha3beta4, and alpha4beta2 nicotinic acetylcholine receptors (nAChRs) expressed in Xenopus oocytes or established cell lines. The present study evaluated bupropion-induced inhibition of native alpha3beta2* and alpha3beta4* nAChRs using functional neurotransmitter release assays, nicotine-evoked [(3)H]overflow from superfused rat striatal slices preloaded with [(3)H]dopamine ([(3)H]DA), and nicotine-evoked [(3)H]overflow from hippocampal slices preloaded with [(3)H]norepinephrine ([(3)H]NE). The mechanism of inhibition was evaluated using Schild analysis. To eliminate the interaction of bupropion with DAT or NET, nomifensine or desipramine, respectively, was included in the superfusion buffer. A high bupropion concentration (100 microM) elicited intrinsic activity in the [(3)H]DA release assay. However, none of the concentrations (1 nM-100 microM) examined evoked [(3)H]NE overflow and, thus, were without intrinsic activity in this assay. Moreover, bupropion inhibited both nicotine-evoked [(3)H]DA overflow (IC(50) = 1.27 microM) and nicotine-evoked [(3)H]NE overflow (IC(50) = 323 nM) at bupropion concentrations well below those eliciting intrinsic activity. Results from Schild analyses suggest that bupropion competitively inhibits nicotine-evoked [(3)H]DA overflow, whereas evidence for receptor reserve was obtained upon assessment of bupropion inhibition of nicotine-evoked [(3)H]NE overflow. Thus, bupropion acts as an antagonist at alpha3beta2* and alpha3beta4* nAChRs in rat striatum and hippocampus, respectively, across the same concentration range that inhibits DAT and NET function. The combination of nAChR and transporter inhibition produced by bupropion may contribute to its clinical efficacy as a smoking cessation agent.     

Facile synthesis and nematicidal activity evaluation of thiophosphinyl amide [(Pz)2P(S)NHR] and thiophosphonyl diamide [(Pz)P(S)(NHR)2] (Pz = 1,3,5-trimethylpyrazole,R = biphenyl derivatives)

A series of thiophosphinyl amide [(Pz)₂P(S)NHR] and thiophosphonyl diamide [PzP(S)(NHR)₂] compounds, where Pz = 1,3,5-trimethylpyrazole and N(H)R = derivatives of 2-aminobiphenyl, were synthesized via a facile two-step process. Reaction of pyrazolyl substituted bromophosphine with 2-aminobiphenyl derivatives and further reaction with elemental sulphur affords the corresponding thiophosphinyl amide and thiophosphonyl diamide. The intermediate species was used without prior purification for reaction with sulphur to yield the target compounds. The nematicidal activity evaluation suggests that some compounds could manifest moderate nematicidal activity towards Meloidogyne incogita, which is higher than that of their amide analogue bixafen.

A series of SDHI (succinate dehydrogenase inhibitor)-like thiophosphinyl amide [(Pz)₂P(S)NHR] and thiophosphonyl diamide [PzP(S)(NHR)₂] compounds, where Pz = 1,3,5-trimethylpyrazole and N(H)R = derivatives of 2-aminobiphenyl, were synthesized via a facile two-step process. Some of their nematicidal activities towards Meloidogyne incogita are stronger than that of the amide analogue bixafen.     

Pharmacokinetics, safety, and efficacy of a liposome encapsulated thymidylate synthase inhibitor, OSI-7904L [(S)-2-[5-[(1,2-dihydro-3-methyl-1-oxobenzo[f]quinazolin-9-yl)methyl]amino-1-oxo-2-isoindolynl]-glutaric acid] in mice

OSI-7904L [(S)-2-[5-[(1,2-dihydro-3-methyl-1-oxobenzo[f]quinazolin-9-yl)methyl]amino-1-oxo-2-isoindolynl]-glutaric acid] is a liposomal formulation of the highly specific, noncompetitive, thymidylate synthase inhibitor OSI-7904 (also known as GW1843, 1843U89, and GS7904). The liposome formulation was developed to enhance the therapeutic index and dose schedule convenience of this potent antifolate compound. The studies presented here were conducted to determine the antitumor efficacy, distribution, pharmacokinetics, and safety of OSI-7904L in mice. In a human colon adenocarcinoma xenograft model in mice, OSI-7904L demonstrated superior antitumor efficacy compared with OSI-7904 or 5-fluorouracil. Furthermore, OSI-7904L could be administered less frequently than OSI-7904 although still generating greater tumor growth inhibition. Distribution studies confirmed that OSI-7904L-treated animals had much greater plasma, tissue, and tumor exposure than did OSI-7904-treated animals. Tumor exposures, based on area under the curve, in OSI-7904L-treated mice were increased over 100-fold compared with tumor exposures in OSI-7904-treated mice. Plasma exposures following OSI-7904L administration were greater than dose proportional consistent with saturation of plasma clearance mechanisms. OSI-7904L was much more toxic than OSI-7904 in the mouse with primary toxicities to the intestines, bone marrow, and thymus. Minimal toxicity to the lungs and liver was noted. These data clearly demonstrated that in mice, OSI-7904L has an increased plasma residence time as well as increased tissue and tumor exposure compared with OSI-7904, thus resulting in increased potency and toxicity. Potential benefits of OSI-7904L include improved efficacy and a more convenient schedule of administration.     

Antiplasmodial activity of [(aryl)arylsulfanylmethyl]Pyridine

A series of [(aryl)arylsufanylmethyl]pyridines (AASMP) have been synthesized. These compounds inhibited hemozoin formation, formed complexes (K(D) = 12 to 20 muM) with free heme (ferriprotoporphyrin IX) at a pH close to the pH of the parasite food vacuole, and exhibited antimalarial activity in vitro. The inhibition of hemozoin formation may develop oxidative stress in Plasmodium falciparum due to the accumulation of free heme. Interestingly, AASMP developed oxidative stress in the parasite, as evident from the decreased level of glutathione and increased formation of lipid peroxide, H(2)O(2), and hydroxyl radical (.OH) in P. falciparum. AASMP also caused mitochondrial dysfunction by decreasing mitochondrial potential (DeltaPsim) in malaria parasite, as measured by both flow cytometry and fluorescence microscopy. Furthermore, the generation of .OH may be mainly responsible for the antimalarial effect of AASMP since .OH scavengers such as mannitol, as well as spin trap alpha-phenyl-n-tertbutylnitrone, significantly protected P. falciparum from AASMP-mediated growth inhibition. Cytotoxicity testing of the active compounds showed selective activity against malaria parasite with selectivity indices greater than 100. AASMP also exhibited profound antimalarial activity in vivo against chloroquine resistant P. yoelii. Thus, AASMP represents a novel class of antimalarial.     

N-[(carbamoylmethyl)amino]ethanesulfonic acid improves phenotyping of alpha 1-antitrypsin by isoelectric focusing on agarose gel

The hereditary deficiency variants of alpha 1-antitrypsin that are associated with diseases such as emphysema are usually identified by use of isoelectric focusing on polyacrylamide gels. Agarose is a simpler, faster, safer, and more reliable medium for this, but resolution often is not as good. I describe a method in which the ultrathin agarose gel contains N-[(carbamoylmethyl)amino]ethanesulfonic acid as a "separator," to flatten the pH gradient and improve separation of the alpha 1-antitrypsin isoforms. The resolution obtained equals or surpasses that of conventional methods based on use of either polyacrylamide or agarose. Haptoglobin, which interferes with isoelectric focusing on polyacrylamide, does not interfere with this method; other advantages are also discussed.     

NNC 55-0396 [(1S,2S)-2-(2-(N-[(3-benzimidazol-2-yl)propyl]-N-methylamino)ethyl)-6-fluoro-1,2,3,4-tetrahydro-1-isopropyl-2-naphtyl cyclopropanecarboxylate dihydrochloride]: a new selective inhibitor of T-type calcium channels

Mibefradil is a Ca2+ channel antagonist that inhibits both T-type and high-voltage-activated Ca2+ channels. We previously showed that block of high-voltage-activated channels by mibefradil occurs through the production of an active metabolite by intracellular hydrolysis. In the present study, we modified the structure of mibefradil to develop a nonhydrolyzable analog, (1S, 2S)-2-(2-(N-[(3-benzimidazol-2-yl)propyl]-N-methylamino)ethyl)-6-fluoro-1,2,3,4-tetrahydro-1-isopropyl-2-naphtyl cyclopropanecarboxylate dihydrochloride (NNC 55-0396), that exerts a selective inhibitory effect on T-type channels. The acute IC(50) of NNC 55-0396 to block recombinant alpha(1)G T-type channels in human embryonic kidney 293 cells was approximately 7 microM, whereas 100 microM NNC 55-0396 had no detectable effect on high-voltage-activated channels in INS-1 cells. NNC 55-0396 did not affect the voltage-dependent activation of T-type Ca2+ currents but changed the slope of the steady-state inactivation curve. Block of T-type Ca2+ current was partially relieved by membrane hyperpolarization and enhanced at a high-stimulus frequency. Washing NNC 55-0396 out of the recording chamber did not reverse the T-type Ca2+ current activity, suggesting that the compound dissolves in or passes through the plasma membrane to exert its effect; however, intracellular perfusion of the compound did not block T-type Ca2+ currents, arguing against a cytoplasmic route of action. After incubating cells from an insulin-secreting cell line (INS-1) with NNC 55-0396 for 20 min, mass spectrometry did not detect the mibefradil metabolite that causes L-type Ca2+ channel inhibition. We conclude that NNC 55-0396, by virtue of its modified structure, does not produce the metabolite that causes inhibition of L-type Ca2+ channels, thus rendering it more selective to T-type Ca2+ channels.     

The antisignaling agent SC-alpha alpha delta 9, 4-(benzyl-(2-[(2,5-diphenyloxazole-4-carbonyl)amino]ethyl)carbamoyl)- 2-decanoylaminobutyric acid,is a structurally unique phospholipid analogue with phospholipase C inhibitory activity

Phospholipids and lipid second messengers mediate mitogenic signal transduction and oncogenesis, but there have been few successful examples of small molecules that affect biologically important phospholipid metabolism. Here we investigated the actions of a previously described antitumor agent, 4-(benzyl-(2-[(2,5-diphenyloxazole-4-carbonyl)amino]ethyl)carbamoyl)- 2-decanoylaminobutyric acid (SC-alpha alpha delta 9), which has antisignaling properties, on phospholipases. Although SC-alpha alpha delta 9 had been shown to be a potent and selective inhibitor of the Cdc25 family of dual-specificity phosphatases, many of its cellular effects are not readily reconciled with phosphatase inhibition. Molecular modeling studies suggested that SC-alpha alpha delta 9 shared several structural features with membrane phospholipids. Enzyme inhibition studies in vitro revealed that SC-alpha alpha delta 9 was a potent inhibitor of phospholipase C (PLC; IC50 = 25 microM) but did not inhibit phospholipase D activity at concentrations up to 100 microM. In H-ras (Q61L)-transformed Rat-1 fibroblasts with constitutively elevated levels of phosphorylated extracellular signal-regulated kinase (Erk), SC-alpha alpha delta 9 inhibited both proliferation and oncogenic Erk activation at concentrations that inhibited PLC in vitro. A SC-alpha alpha delta 9 congener that lacked antiproliferative activity also did not inhibit PLC in vitro. In the PLC-dependent scratch wound healing model, SC-alpha alpha delta 9 was 10-fold more potent than the phosphatidylcholine-specific PLC inhibitor D-609. We propose that the structural resemblance of SC-alpha alpha delta 9 to phospholipids allows it to inhibit cellular PLC, thereby providing a possible molecular mechanism for SC-alpha alpha delta 9's effects on oncogenic Erk activation.