环氧合酶-2和5-脂氧化酶双重抑制剂的研究进展

传统的非甾体抗炎药和选择性环氧合酶-2(COX-2)抑制剂在治疗炎症过程中引发胃肠道及肾脏不良反应,制约了其临床应用。COX-2和5-脂氧化酶(5-LOX)双重抑制剂同时抑制前列腺素(PGs)和炎症介质白三烯类(LTs)的生物合成,比单一的抑制剂抗炎效果好、安全性高,是一类有发展前景的新型非甾体抗炎药。笔者简要介绍COX-2/5-LOX双重抑制剂的研究进展,并讨论其作用机制及构效关系     

环氧合酶／5-脂氧合酶双重抑制剂的研究进展

非甾体类抗炎药(NSAID)广泛用于各种炎症的治疗。长期使用经典的NSAID会产生严重的副作用,尤其是胃肠道副作用。为避免经典的NSAID的副作用,开发出了选择性COX-2抑制剂,但长期使用选择性COX-2抑制剂对心血管系统有副作用。COX/5-LOX双重抑制剂通过同时阻断炎症介质前列腺素和白三烯的形成,产生协同的抗炎作用,有望提高疗效,同时避免COX抑制剂引发的副作用。本文对COX/5-LOX双重抑制剂的抗炎镇痛作用机制,以及研究现状进行综述。     

三环类环氧合酶-2选择性抑制剂的构效关系

按照中心环的结构分类综述三环类环氧合酶-2(COX-2)选择性抑制剂的构效关系。三环类COX-2选择性抑制剂是目前非甾体抗炎药中研究最多、也是最富有成果的一类化合物。     

寻找环氧合酶-2选择性抑制剂的新途径：对经典非甾体类抗炎药的结构改造

典型的环氧合酶-2(COX-2)选择性抑制剂对COX-2抑制选择性高，胃肠道副作用小，但在炎症组织分布选择性低，有心血管方面的副作用。本文分析了典型COX-2选择性抑制剂心血管危险性产生的机制，指出探索更安全的COX-2选择性抑制剂的一个有效途径是对经典非甾体类抗炎药(NSAID)结构的合理改造，保持药物分子在炎症组织分布的高选择性，提高对COX-2抑制的选择性；同时，对经典NSAID结构改造的研究进展进行了综述。     

非甾体抗炎药环氧化酶/5-脂氧化酶双重抑制剂的研究进展

非甾体抗炎药具有解热、镇痛、抗炎和抗风湿等作用。现有的非甾体抗炎药大多存在胃肠道不良反应或心脏病发作和心肌梗死等方面的副作用,而环氧化酶/5-脂氧化酶双重抑制剂不仅具有较强的解热、镇痛、抗炎和抗风湿等作用,而且未发现有心脏病发作、心肌梗死和胃肠道损伤的危险,因此环氧化酶/5-脂氧化酶双重抑制剂已成为研究新一代非甾体抗炎药的途径。     

选择性环氧合酶-2抑制剂的研究现状及进展

非甾体抗炎药（NSAIDs）是临床上应用非常广泛的一类药物，但严重的不良反应使其应用受到很大限制。研究已经发现，NSAIDs对炎症的有效治疗源干其对环氧合酶-2（COX-2）的抑制作用。综述了选择性COX-2抑制剂作用的分子基础、构效关系及其目前研究开发的现状和最新进展。     

新结构类型环氧化酶-2抑制剂的研究进展

非甾体抗炎药环氧化酶-2(COX-2)选择性抑制剂的应用已超过百年历史,近年来发现部分COX-2选择性抑制剂引起较为严重的心血管不良反应(如卒中、心肌梗死等),限制了其临床应用.因此,寻找更加安全、有效的新结构类型的COX-2选择性抑制剂已成为非甾体抗炎药的研究热点.文中通过文献调研,综述近年来利用人工合成、药效团筛选、天然产物提取分离得到的COX-2选择性抑制剂的研究进展.     

塞来昔布抗乳腺癌的临床应用

目前研究发现环氧化酶-2（COX-2）与乳腺癌的发生有密切联系.COX-2及其催化产物前列腺素（PGs）参与炎症的多种过程,且可通过多种致病机制参与多种实体瘤的发生、发展过程.塞来昔布作为新型非甾体类抗炎药（NASIDs）,是一种高选择性的COX-2抑制剂,国内外的研究表明,其对上皮组织癌有一定的抑制作用.该文就塞来昔布抗乳腺癌的机制及其临床研究进行了综述.     

darbufelone对胃癌SGC-7901细胞增殖、凋亡的影响

目的观察环氧合酶-2/5-脂氧合酶双重抑制剂dar-bufelone对胃癌SGC-7901细胞生长的影响。方法MTT法测定darbufelone对胃癌SGC-7901细胞增殖的影响;TUNEL法检测细胞凋亡;RT-PCR法分析SGC-7901细胞中5-LOX和COX-2 mRNA的表达;免疫细胞化学法检测胃癌SGC-7901细胞中5-LOX和COX-2蛋白质的表达。结果dar-bufelone以时间剂量依赖的方式抑制SGC-7901细胞增殖;1.5×10-5、1.0×10-5和5×10-6mol.L-1darbufelone作用72 h后,细胞凋亡率分别为(30.3±2.1)%、(23.0±2.0)%和(15.0±1.5)%,均高于对照组(0.6±0.1)%(P<0.01);1.5×10-5、1.0×10-5和5×10-6mol.L-1darbufelone处理胃癌SGC-7901细胞72 h后,5-LOX和COX-2 mRNA及其蛋白质表达均减少(P<0.05)。结论环氧合酶-2/5-脂氧合酶双重抑制剂darbufelone对人胃癌SGC-7901细胞株有抑制增殖、诱导凋亡的作用。     

特异性环氧化酶Ⅱ抑制剂的进展与评价

特异性环氧化酶Ⅱ(COX-2)抑制剂,塞来昔布和罗非昔布在西方上市已近5个年头,在国内也已超过3年.虽然存在争议,而且现有的特异性COX-2抑制剂仍有许多不足,例如心脑血管病安全性受到质疑,诱发水肿和高血压等问题.但是,它的确可以成为非甾体抗炎药(NSAID)发展史上的一个里程碑.     

Molecular determinants for the interaction of the valvulopathic anorexigen norfenfluramine with the 5-HT2B receptor

S-(+)-Norfenfluramine (SNF)-an active metabolite of the now-banned anorexigen fenfluramine-has been implicated in the drug's appetite-suppressing actions and its life-threatening cardiovascular side effects. SNF reduces appetite through serotonin 5-HT(2C) receptor activation; it causes cardiopulmonary side effects through 5-HT(2B) receptor activation. Thus, we attempted to identify molecular determinants of SNF binding to 5-HT(2B) receptors distinct from those underlying SNF-5-HT(2C/2A) receptor interactions. Mutagenesis implicated Val2.53 in SNF binding to 5-HT(2B) receptors. Ligand docking simulations suggested both Val2.53 gamma-methyl groups form stabilizing van der Waals' (vdW) interactions with the alpha-methyl group of SNF. A V2.53L mutation induced a 17-fold decrease in affinity; molecular dynamics (MD) simulations suggested that this decrease resulted from the loss of one 2.53-alpha-methyl group vdW interaction. Supporting this, 1) the binding of norfenfluramine (NF) analogs lacking an S-(+) alpha-methyl group (RNF and alpha-desmethyl-NF) was less sensitive to the V2.53L mutation, and 2) a V2.53A mutation decreased SNF affinity 190-fold, but decreased RNF and alpha-desmethyl-NF affinities only 16- and 45-fold, respectively. We next addressed whether the alpha-methyl group of SNF contributes to 5-HT(2C/2A) receptor affinity. Removal of the alpha-methyl group (RNF and alpha-desmethyl-NF), which reduced 5-HT(2B) receptor binding 3-fold, did not affect 5-HT(2C/2A) receptor binding. An alpha-ethyl substituent (alpha-ethyl-NF), which decreased 5-HT(2B) receptor affinity 46-fold, reduced 5-HT(2C) and 5-HT(2A) receptor binding by 14- and 5-fold, respectively. Finally, we determined that residue 2.53 affects SNF potency and efficacy at 5-HT(2B) receptors but not at 5-HT(2C) and 5-HT(2A) receptors. In conclusion, vdW interactions between residue 2.53 and the alpha-methyl group of SNF contribute to the ligand's 5-HT(2) receptor subtype-selective pharmacology.     

Studies on the synthesis andin vitro antitumor activity of the isoquinolone derivatives

3-Arylisoquinolin-1(2H)-ones (2) are possible bioisosteres of the 5-[4'-(piperidinomethyl)phenyl]-2,3-dihydroimidazo[2,1-a]iso quinoline (1) which is in clinical evaluation for the treatment of cancer. Structure-activity relationship studies of 3-arylisoquinolin-1(2H)-ones (2) led to the synthesis of 3-arylquinolin-2(1H)-ones (3). A number of 3-phenyl substituted quinolin-2(1H)-ones were synthesized and tested for their in vitro antitumor activity against four different human tumor cell lines and 3-phenyl-N-benzyl-3,4-dihydroquinolin-2(1H)-one (12) showed the most potent activity.     

Hydrogen sulfide and inflammation: the good, the bad, the ugly and the promising

Hydrogen sulfide is rapidly gaining ground as a physiological mediator of inflammation, but there is no clear consensus as to its precise role in inflammatory signaling. This article discusses the disparate anti-inflammatory ('the good') and proinflammatory ('the bad') effects of endogenous and pharmacological H(2)S in disparate animal model and cell culture systems. We also discuss 'the ugly', such as problems of using wholly specific inhibitors of enzymatic H(2)S synthesis, and the use of pharmacological donor compounds, which release H(2)S too quickly to be physiologically representative of endogenous H(2)S synthesis. Furthermore, recently developed slow-release H(2)S donors, which offer a more physiological approach to understanding the complex role of H(2)S in acute and chronic inflammation ('the promising') are discussed.     

Advance in understanding the biosynthesis of prostacyclin and thromboxane A2 in the endoplasmic reticulum membrane via the cyclooxygenase pathway

Recent advances in topological and structural characterization of the prostacyclin (PGI(2)) and thromboxane A(2) (TXA(2)) synthases have led to the understanding of the biosynthesis of PGI(2) and TXA(2) at a structural level. This mini-review focuses on the molecular mechanism of the isomerization of the prostaglandin H(2) to PGI(2)and TXA(2) by their synthases in the endoplasmic reticulum (ER) membrane coordinated with cyclooxygenase-1 or -2. This review summarizes the evidences in which the biosynthesis of PGI(2)and TXA(2) are influenced/modulated by the membrane anchor residues of the synthases and the ER membrane itself, and provides the structural basis for engineering the synthases for the next generation of gene therapy and drug designs targeting the specific synthases.     

Comparison of H2O2-induced vasoconstriction in the abdominal aorta and mesenteric artery of the mouse

Hydrogen peroxide (H(2)O(2)) is generally perceived as an arterial vasodilator. Due to the emerging importance of H(2)O(2) as a possible vasoconstrictor, we examined whether H(2)O(2) constricts both the abdominal aorta and superior mesenteric artery and postulated that H(2)O(2) is a ubiquitous constrictor of quiescent mouse arteries. Moreover, we postulated that KCl depolarization discloses and/or exaggerates H(2)O(2)-induced constriction. Under quiescent conditions, H(2)O(2) constricted the mouse abdominal aorta but not the mesenteric artery. Vessel depolarization (a) exaggerated this constrictor response in the aorta, and (b) unmasked a contractile response in the mesenteric artery. Our final hypothesis tested whether tyrosine kinases, mitogen-activated protein kinases (MAPKs), and/or Rho-kinase are uniformly involved in H(2)O(2)-induced vasoconstriction. We observed a marked difference in the ability of tyrosine kinase inhibitor to block H(2)O(2)-induced vasoconstriction. p38 and ERK 1/2MAPK inhibitors reduced the maximal response to H(2)O(2), whereas JNK inhibitor had no effect. Finally, Rho-kinase inhibitor decreased the H(2)O(2) response in the mesenteric artery but not in the aorta. These data demonstrate a variable yet tightly regulated H(2)O(2) vasoconstrictor effect. Furthermore, we found that p38, ERK 1/2 and Rho-kinase play a role in H(2)O(2) constriction, which may be critical pathways involved in H(2)O(2)-induced constriction across vascular beds.     

Synthesis and biological activities of pseudopeptide analogues of the C-terminal heptapeptide of cholecystokinin. On the importance of the peptide bonds

A series of pseudopeptide analogues of the C-terminal heptapeptide of cholecystokinin in which each peptide bond, one at a time, has been replaced by a CH2NH bond were synthesized: Z-Tyr(SO3-)-Nle-Gly-Trp-Nle-Asp psi-(CH2NH)Phe-NH2 (1), Z-Tyr(SO3-)-Nle-Gly-Trp-Nle psi (CH2NH)Asp-Phe-NH2 (2), Z-Tyr(SO3-)-Nle-Gly-Trp psi-(CH2NH)Nle-Asp-Phe-NH2 (3), Z-Tyr(SO3-)-Nle-Gly psi(CH2NH)Trp-Nle-Asp-Phe-NH2 (4), Z-Tyr(SO3-)-Nle psi-(CH2NH)Gly-Trp-Nle-Asp-Phe-NH2 (5), Z-Tyr(SO3-)-Met-Gly-Trp-Nle-Asp psi (CH2NH)Phe-NH2 (6), Z-Tyr-(SO3-)-Met-Gly-Trp-Nle psi (CH2NH)Asp-Phe-NH2 (7), Z-Tyr(SO3-)-Met-Gly-Trp psi (CH2NH)Nle-Asp-Phe-NH2 (8). These derivatives were studied for their ability to stimulate amylase release from rat pancreatic acini and to inhibit the binding of labeled CCK-9 to rat pancreatic acini and to guinea pig brain membrane CCK receptors. They were compared to the potent CCK-8 analogue Boc-Asp-Tyr(SO3-)-Nle-Gly-Trp-Nle-Asp-Phe-NH2. All of these pseudopeptides were able to stimulate amylase secretion with the same efficacy as CCK-8 but with varying potencies. These compounds were also potent in inhibiting the binding of labeled CCK-9 to CCK receptors from rat pancreatic acini and from guinea pig brain membranes.     

Alpha2-adrenoceptor subtypes involved in the regulation of catecholamine release from the adrenal medulla of mice

BACKGROUND AND PURPOSE: This study was carried out to elucidate which alpha(2)-adrenoceptor subtypes mediated the inhibition of noradrenaline and adrenaline release from the adrenal medulla of mice. EXPERIMENTAL APPROACH: Isolated adrenal medullae from wild-type and alpha(2A), alpha(2B) and alpha(2C)-adrenoceptor knockout (KO) mice were placed in superfusion chambers. Catecholamine overflow was evoked by 1,1-dimethyl-4-phenylpiperazinium (500 microM) in absence or in presence of the alpha(2)-adrenoceptor agonist medetomidine. The effect of medetomidine was tested in presence of the alpha-adrenoceptor antagonists rauwolscine, WB 4101, spiroxatrine, phentolamine and prazosin. KEY RESULTS: In wild-type mice, medetomidine reduced noradrenaline and adrenaline overflow in a concentration-dependent manner (EC(50) in nM: 1.54 and 1.92; E(max) in % of inhibition: 91 and 94, for noradrenaline and adrenaline, respectively). The pK (D) values of the antagonists for noradrenaline overflow did not correlate with pK(D) values at alpha(2A), alpha(2B), or alpha(2C) binding sites. The pK (D) values of the antagonists for adrenaline overflow correlated positively with pK(D) values at alpha(2C) binding sites (opossum kidney cells). The effect of medetomidine (100 nM) on noradrenaline overflow was significantly reduced in all three alpha(2)KO mice (57, 54, 44 % inhibition, for alpha(2A), alpha(2B), and alpha(2C), respectively), whereas the effect of medetomidine on adrenaline overflow was greatly reduced in alpha(2C)KO mice (14 % inhibition). CONCLUSIONS AND IMPLICATIONS: In the adrenal medulla of mice, all three alpha(2)-adrenoceptor subtypes (alpha(2A), alpha(2B), and alpha(2C)) play an equal role in the inhibition of noradrenaline overflow, whereas the alpha(2C)-adrenoceptor is the predominant alpha(2)-adrenoceptor subtype involved in the inhibitory mechanism controlling adrenaline overflow.     

Mechanisms underlying the neurokinin A-induced contraction of the pregnant rat myometrium

1. Using fura-PE3 fluorimetry and alpha-toxin permeabilization, the characteristics of the contractile responses to neurokinin A (NKA) were determined in the pregnant rat myometrium. 2. NKA induced contractions in rat myometrium in a concentration-dependent manner. There were no significant differences in the maximum contractions and EC(50) values between the pregnant and non-pregnant myometrium, however, the contraction of only the former was greatly enhanced in the presence of phosphoramidon (PPAD), an endopeptidase inhibitor. 3. In the pregnant myometrium, NKA induced sustained increases in [Ca(2+)](i) and tension in normal physiological saline solution, while only small transient increases in [Ca(2+)](i) and tension were observed in Ca(2+)-free solution. 4. Both diltiazem (10 microM) and SK-F 96365 (10 microM) significantly inhibited the NKA-induced elevations of [Ca(2+)](i) and tension. The effects were additive when these drugs were used together. 5. NKA induced a significant leftward shift of the [Ca(2+)](i)-tension curve obtained by changing the external Ca(2+) (0 - 2.5 mM) during depolarization with high K(+) solution. This Ca(2+)-sensitizing effect by NKA was also observed in the alpha-toxin permeabilized myometrium. 5. These results indicated that in the pregnant rat myometrium: (1) the responsiveness to NKA increased, although it was masked by the increase in the endopeptidase activity; (2) NKA induced contractions of the myometrium by increasing both [Ca(2+)](i) and the myofilament Ca(2+) sensitivity and (3) The NKA-induced [Ca(2+)](i) elevation was partly due to the intracellular Ca(2+) release and mainly due to the Ca(2+) influx, which was thought to be through both voltage dependent calcium channels and non-specification channels.     

Mutations of the 2' proline in the M2 domain of the human GABAC rho1 subunit alter agonist responses

Mutations of the proline residue at the 2' position (P2') within the second transmembrane (M2) domain of the gamma-aminobutyric acid(C) (GABA(C)) rho1 subunit are known to produce receptors with altered pharmacology. In the present study, P2' was mutated to alanine (rho1P2'A), phenylalanine (rho1P2'F), glycine (rho1P2'G) and serine (rho1P2'S). Mutant receptors were characterized using a range of agonists, partial agonists and antagonists. rho1P2'A, rho1P2'G and rho1P2'S receptors were less susceptible than wild-type receptors to agonist activation. Most notably, the partial agonists, (+/-)-trans-2-(aminomethyl)cyclopropanoic acid ((+/-)-TAMP) and imidazole-4-acetic acid (I4AA) were converted to antagonists at rho1P2'G and rho1P2'S receptors and the partial agonist CACA acted as an antagonist at rho1P2'S receptors. In contrast, rho1P2'F receptors were more prone to activation by agonists. A correlation was observed between the pharmacological properties of the mutant receptors and the hydrophobicity of each residue. Unlike the agonists or partial agonists, the affinity of competitive antagonists, (1,2,5,6-tetrahydropyridine-4-yl)methylphosphinic acid (TPMPA) and 4,5,6,7-tetrahydroisoxazole[4,5-c]pyridine-3-ol (THIP), did not change significantly between wild-type and mutant receptors. Thus, the results suggest that the agonist/competitive antagonist binding site(s) were not significantly affected by the mutations, but that receptor activation properties altered such that the more hydrophobic the residue at the 2' position, the more prone the receptor is to agonist activation.     

Genotoxicity and ecotoxicity assays using the freshwater crustacean Daphnia magna and the larva of the aquatic midge Chironomus riparius to screen the ecological risks of nanoparticle exposure

Genotoxic and ecotoxic assessments of widely used nanoparticles, cerium dioxide (CeO(2)), silicon dioxide (SiO(2)) and titanium dioxide (TiO(2)), were conducted on two aquatic sentinel species, the freshwater crustacean Daphnia magna and the larva of the aquatic midge Chironomus riparius. CeO(2) may have genotoxic effects on D. magna and C. riparius, given that the DNA strand breaks increased in both species when exposed to this nanoparticle; whereas, neither exposure to SiO(2) nor TiO(2) had a genotoxic effect on either species. A statistically significant correlation was observed between DNA damage and mortality in the CeO(2)-exposed C. riparius, which suggests that CeO(2)-induced DNA damage might provoke higher-level consequences. SiO(2) did not seem to affect the DNA integrity; whereas, the mortality of both the SiO(2)-exposed D. magna and C. riparius increased. The TiO(2) nanoparticle did not lead to significant alterations in geno- or ecotoxic parameters of both species. Overall, these results suggest that CeO(2) nanoparticles may be genotoxic toward aquatic organisms, which may contribute to the knowledge relating to the aquatic toxicity of the most widely used nanomaterials on aquatic ecosystems, for which little data are available.