Estrogen receptor ligands. Part 13: Dihydrobenzoxathiin SERAMs with an optimized antagonist side chain

An optimized side chain for dihydrobenzoxathiin SERAMs was discovered and attached to four dihydrobenzoxathiin platforms. The novel SERAMs show exceptional estrogen antagonist activity in uterine tissue and an MCF-7 breast cancer cell assay.     

Synthesis, analysis and rearrangement of novel unnatural glucosinolates

As part of a structure activity study to examine the interaction of glucosinolates with leaf surfaces, a number of glucosinolates were synthesised bearing novel side chain functionalities. These included 7-carboxyheptyl, heptyl, and naphthyl side chains. For the carboxyheptyl glucosinolate, a novel intramolecular rearrangement reaction was observed during the final deprotection step, which generated an ester attached to the C-3 of glucose. Studies by 1H NMR spectroscopy showed that the hydrophobic side chain associated with one face of the glucose ring and it was proposed that this was the driving force for the rearrangement. Similar hydrophobic interactions were also observed between the heptyl and naphthyl side chains and the glucose.     

Synthesis and anthelmintic activity of cyclohexadepsipeptides with cyclohexylmethyl side chains

Cyclohexadepsipeptides (CHDPs) with cyclohexylmethyl side chains represent novel enniatins with in vivo activity against the parasitic nematode Haemonchus contortus Rudolphi in sheep. It was found that the replacement of benzylic by cyclohexylmethyl side chains on the enniatin skeleton can increase anthelmintic efficacy. Here we report on a simple total synthesis of the precursors for this type of CHDPs and an efficient chemical transformation of the benzylic into the corresponding cyclohexylmethyl side chains.     

Comparative structure-activity relationship studies of 1-(5-methylsulfonylpyrid-2-yl)-5-alkyl and (hetero)aryl triazoles and pyrazoles in canine COX inhibition

Structure-activity relationship (SAR) studies of novel 5-alkyl and 5-aryl/heteroaryl substituted 1,2,4-triazoles are described. The in vitro activity is compared to the pyrazole class of compounds with analogous side chains to delineate the contribution of the triazole ring nitrogen in binding to the active site. Both series are quite potent and selective in the canine whole blood (CWB) COX-2 assay, suggesting the increased binding contribution of the hydrophobic side chains.     

Novel alpha-amino-acid phenolic ester derivatives with intravenous anaesthetic activity

A novel series of alpha-amino-acid phenolic ester derivatives containing sulphide, sulphoxide, sulphone, ester and amide side chains were prepared and shown to display potent intravenous anaesthetic activity.     

Piperidino-hydrocarbon compounds as novel non-imidazole histamine H(3)-receptor antagonists

In search for novel non-imidazole histamine H(3)-receptor antagonists, piperidino-hydrocarbon compounds were synthesized using the known non-imidazole histamine H(3)-receptor antagonist FUB 637 (3-phenylpropyl 3-piperidinopropyl ether) as lead structure. Piperidino-alkyl derivatives containing highly flexible side chains (2, 4-7) were prepared via N-alkylation. Compounds containing unsaturated alkyl groups were synthesized in order to investigate the impact of rigidifying the side chain (8-16). Terminal alkynes were prepared by alkylation of lithium acetylide-ethylenediamine complex, disubstituted alkynes were synthesized by alkylation of the appropriate acetylene in the presence of n-butyllithium-N,N,N',N'-tetramethylene-ethylene-diamine complex. The novel compounds were investigated in an in vitro functional assay on the guinea-pig ileum, in which N-(7-phenylhept-3-ynyl)piperidine (14) proved to be of good potency in this class (pA(2)=7.21). In an in vivo assay the compounds were additionally screened for their abilities to influence central H(3)-histaminergic neuron activity in mice with regard to their oral availabilities and distribution properties. In this screening, N-pent-4-ynylpiperidine (9) and N-hex-5-ynylpiperidine (10) proved to be highly potent and orally available histamine H(3)-receptor antagonists. The ED(50) values for 9 and 10 were 1.3 and 1.4mg/kg po, respectively, which is in the potency range of the reference antagonist thioperamide.     

Orally efficacious NR2B-selective NMDA receptor antagonists

A novel series of benzamidines was synthesized and shown to exhibit NR2B-subtype selective NMDA antagonist activity. Compound 31 is orally active in a carrageenan-induced rat hyperalgesia model of pain and shows no motor coordination side effects.     

Aminopeptidase C of Aspergillus niger is a novel phenylalanine aminopeptidase

A novel enzyme with a specific phenylalanine aminopeptidase activity (ApsC) from Aspergillus niger (CBS 120.49) has been characterized. The derived amino acid sequence is not similar to any previously characterized aminopeptidase sequence but does share similarity with some mammalian acyl-peptide hydrolase sequences. ApsC was found to be most active towards phenylalanine beta-naphthylamide (F-beta NA) and phenylalanine para-nitroanilide (F-pNA), but it also displayed activity towards other amino acids with aromatic side chains coupled to beta NA; other amino acids with non-aromatic side chains coupled to either pNA or beta NA were not hydrolyzed or were poorly hydrolyzed. ApsC was not able to hydrolyze N-acetylalanine-pNA, a substrate for acyl-peptide hydrolases.     

The Inhibitory Effects of a Rhamnogalacturonan Ι (RG-I) Domain from Ginseng Pectin on Galectin-3 and Its Structure-Activity Relationship

Pectin has been shown to inhibit the actions of galectin-3, a β-galactoside-binding protein associated with cancer progression. The structural features of pectin involved in this activity remain unclear. We investigated the effects of different ginseng pectins on galectin-3 action. The rhamnogalacturonan I-rich pectin fragment, RG-I-4, potently inhibited galectin-3-mediated hemagglutination, cancer cell adhesion and homotypic aggregation, and binding of galectin-3 to T-cells. RG-I-4 specifically bound to the carbohydrate recognition domain of galectin-3 with a dissociation constant of 22.2 nm, which was determined by surface plasmon resonance analysis. The structure-activity relationship of RG-I-4 was investigated by modifying the structure through various enzymatic and chemical methods followed by activity tests. The results showed that (a) galactan side chains were essential to the activity of RG-I-4, whereas arabinan side chains positively or negatively regulated the activity depending on their location within the RG-I-4 molecule. (b) The activity of galactan chain was proportional to its length up to 4 Gal residues and largely unchanged thereafter. (c) The majority of galactan side chains in RG-I-4 were short with low activities. (d) The high activity of RG-I-4 resulted from the cooperative action of these side chains. (e) The backbone of the molecule was very important to RG-I-4 activity, possibly by maintaining a structural conformation of the whole molecule. (f) The isolated backbone could bind galectin-3, which was insensitive to lactose treatment. The novel discovery that the side chains and backbone play distinct roles in regulating RG-I-4 activity is valuable for producing highly active pectin-based galectin-3 inhibitors.     

Synthesis of cytotoxic novel 9,11-secosterol analogs: Structure/activity studies

In an effort to determine the pharmaceutical utility and the structural requirements for activity against tumor cell lines, 30 novel 9,11-secosterol analogues with different side chains and degrees of oxidation at C-9 were synthesized starting from hecogenin. Evaluation of the synthesized compounds for cytotoxicity against KB, HeLa and MCF-7 cell lines revealed that some important structural features are required for activity. The presence of a cholesterol-type side chain, which appears to play a major role in determining the biological activity, the existence of a ketone functional at C-9 is also crucial for anticancer activity whereas hydroxyl/ketone function at C-22 on the side chain did not increase cytotoxicity.     

Helical side chain chemistry of a peptoid-based SP-C analogue: Balancing structural rigidity and biomimicry

Surfactant protein C (SP-C) is an important constituent of lung surfactant (LS) and, along with SP-B, is included in exogenous surfactant replacement therapies for treating respiratory distress syndrome (RDS). SP-C's biophysical activity depends upon the presence of a rigid C-terminal helix, of which the secondary structure is more crucial to functionality than precise side-chain chemistry. SP-C is highly sequence-conserved, suggesting that the β-branched, aliphatic side chains of the helix are also important. Nonnatural mimics of SP-C were created using a poly-N-substituted glycine, or “peptoid,” backbone. The mimics included varying amounts of α-chiral, aliphatic side chains and α-chiral, aromatic side chains in the helical region, imparting either biomimicry or structural rigidity. Biophysical studies confirmed that the peptoids mimicked SP-C's secondary structure and replicated many of its surface-active characteristics. Surface activity was optimized by incorporating both structurally rigid and biomimetic side chain chemistries in the helical region indicating that both characteristics are important for activity. By balancing these features in one mimic, a novel analogue was created that emulates SP-C's in vitro surface activity while overcoming many of the challenges related to natural SP-C. Peptoid-based analogues hold great potential for use in a synthetic, biomimetic LS formulation for treating RDS.     

Design, synthesis and cell growth inhibitory activity of a series of novel aminosubstituted xantheno[1,2-d]imidazoles in breast cancer cells

A series of novel aminosubstituted xantheno[1,2-d]imidazole derivatives have been designed and synthesized and their antiproliferative activity has been evaluated against human breast MDA-MB-231 cell line. Among the tested compounds those bearing two basic side chains at 2- and 5-positions exhibited a strong dose-dependent antiproliferative activity. Increase of the size and basicity of the N-alkyl substituent resulted in amplification of the inhibitory activity.     

Immunoglobulin-free light chains elicit immediate hypersensitivity-like responses

Immunoglobulin (Ig)-free light chains IgLC are present in serum and their production is augmented under pathological conditions such as multiple sclerosis, rheumatoid arthritis and neurological disorders. Until now, no (patho)physiological function has been ascribed to circulating Ig light chains. Here we show that IgLCs can confer mast cell dependent hypersensitivity in mice. Antigenic stimulation results in plasma extravasation, cutaneous swelling and mast-cell degranulation. We show that IgLCs have a crucial role in development of contact sensitivity, which could be completely prevented by a novel IgLC antagonist. Although IgE and IgG(1) are central to the induction of immediate hypersensitivity reactions, our results show that IgLCs have similar activity. IgLCs may therefore be a novel factor in the humoral immune response to antigen exposure. Our findings open new avenues in investigating the pathogenesis of autoimmune diseases and their treatments.     

Synthesis and SAR studies of novel antifungal 1,2,3-triazines

A novel series of pyridothieno-1,2,3-triazines with potent antifungal activity against Erysiphe graminis f. sp. tritici has been discovered. Two complementary synthetic routes to compounds of this type have been developed and used to efficiently explore the structure-activity relationships around the lead compound. The incorporation of oxygen atoms into the side chains of the molecules has allowed the solubility of the compounds to be increased 10-fold whilst retaining biological activity.     

双特异性抗体副产物去除策略

双特异性抗体是一种可以同时结合两种靶点的抗体,与单特异性抗体相比具有疗效高、毒副作用小的优点,因此成为近年来的研究热点。但双特异性抗体是由两种不同的重链和轻链所组成,而且重、轻链的表达难以控制在同一水平,因此在双特异性抗体的组装过程中极易出现各种错配副产物,大大增加了下游纯化的难度与成本。近年来,多家制药公司研发出商业化的双特异性抗体制备平台,这些平台利用独特的分子设计策略极大提升了双特异性抗体的组装成功率。然而,各种双抗分子设计策略不足以完全避免副产物的产生,因此还需要配合各种层析方式来进一步去除双抗分子副产物以提升产品质量。综述了近年来几种主流双特异性抗体研发设计平台,系统归纳了用于去除同源二聚体、半抗体、3/4抗体及聚集体的层析方法,以期为双特异性抗体纯化提供理论依据。     

Mechanism of dihydropyridine interaction with critical binding residues of L-type Ca2+ channel alpha 1 subunits

We investigated the mechanism of interaction of individual L-type channel amino acid residues with dihydropyridines within a dihydropyridine-sensitive alpha1A subunit (alpha1A(DHP)). Mutation of individual residues in repeat III and expression in Xenopus oocytes revealed that Thr(1393) is not required for dihydropyridine interaction but that bulky side chains (tyrosine, phenylalanine) in this position sterically inhibit dihydropyridine coordination. In position 1397 a side chain carbonyl group was required for high antagonist sensitivity. Agonist function required the complete amide group of a glutamine residue. Val(1516) and Met(1512) side chains were required for agonist (Val(1516)) and antagonist (Val(1516), Met(1512)) sensitivity. Replacement of Ile(1504) and Ile(1507) by alpha1A phenylalanines was tolerated. Substitution of Thr(1393) by phenylalanine or Val(1516) by alanine introduced voltage dependence of antagonist action into alpha1A(DHP), suggesting that these residues form part of a mechanism mediating voltage dependence of dihydropyridine sensitivity. Our data provide important insight into dihydropyridine binding to alpha1A(DHP) which could facilitate the development of alpha1A-selective modulators. By modulating P/Q-type Ca(2+) channels such drugs could serve as new anti-migraine therapeutics.