Design, synthesis, molecular modelling and in vitro screening of monoamine oxidase inhibitory activities of novel quinazolyl hydrazine derivatives

Funding: Deanship of Scientific Research at Taibah University, Al-Madinah Al-Munawarah, Saudi Arabia (project # 7101).A new series of N'-substituted benzylidene-2-(4-oxo-2-phenyl-1,4-dihydroquinazolin-3(2H)-yl)acetohydrazide (5a-5h) has been synthesized, characterized by FT-IR, NMR spectroscopy and mass spectrometry and tested against human monoamine oxidase (MAO) A and B. Only (3-methoxy-4-hydroxy)benzoyl substituted compounds gave submicromolar inhibition of MAO-A and MAO-B. Changing the phenyl substituent to methyl on the unsaturated quinazoline ring (12a-12d) decreased inhibition but a less flexible linker (14a-14d) resulted in selective micromolar inhibition of hMAO B providing insight for ongoing design.Publisher PDFPeer reviewe

Ascites induces modulation of α6β1 integrin and urokinase plasminogen activator receptor expression and associated functions in ovarian carcinoma

Interactions between cancer cells and the surrounding medium are not fully understood. In this study, we demonstrate that ascites induces selective changes in the expression of integrins and urokinase plasminogen activator/urokinase plasminogen activator receptor (uPA/uPAR) in ovarian cancer cells. We hypothesise that this change of integrin and uPA/uPAR expression triggers signalling pathways responsible for modulating phenotype-dependent functional changes in ovarian cancer cells. Human ovarian surface epithelial (HOSE) cell lines and epithelial ovarian cancer cell lines were treated with ascites for 48 h. Ascites induced upregulation of α6 integrin, without any change in the expression of αv, β1 and β4 integrin subunits. Out of the four ovarian cancer cell lines studied, ascites induced enhancement in the expression of uPA/uPAR in the more invasive OVCA 433 and HEY cell lines without any change in the noninvasive OVHS1 and moderately invasive PEO.36 cell lines. On the other hand, no change in the expression of α6 integrin or uPAR, in response to ascites, was observed in HOSE cells. In response to ascites, enhancement in proliferation and in adhesion was observed in all four ovarian cancer cell lines studied. In contrast, no significant increase in proliferation or adhesion by ascites was observed in HOSE cells. Ascites-induced expression of uPA/uPAR correlated with the increased invasiveness of HEY and OVCA 433 cell lines but was not seen in OVHS1, PEO.36 and HOSE cell lines. Upregulation of α6 integrin and uPA/uPAR correlated with the activation of Ras and downstream Erk pathways. Ascites-induced activation of Ras and downstream Erk can be inhibited by using inhibitory antibodies against α6 and β1 integrin and uPAR, consistent with the inhibition of proliferation, adhesion and invasive functions of ovarian cancer cell lines. Based on these findings, we conclude that ascites can induce selective upregulation of integrin and uPA/uPAR in ovarian cancer cells and these changes may modulate the functions of ovarian carcinomas

In silico modeling of the specific inhibitory potential of thiophene-2,3-dihydro-1,5-benzothiazepine against BChE in the formation of β-amyloid plaques associated with Alzheimer's disease

<p>Abstract</p> <p>Background</p> <p>Alzheimer's disease, known to be associated with the gradual loss of memory, is characterized by low concentration of acetylcholine in the hippocampus and cortex part of the brain. Inhibition of acetylcholinesterase has successfully been used as a drug target to treat Alzheimer's disease but drug resistance shown by butyrylcholinesterase remains a matter of concern in treating Alzheimer's disease. Apart from the many other reasons for Alzheimer's disease, its association with the genesis of fibrils by β-amyloid plaques is closely related to the increased activity of butyrylcholinesterase. Although few data are available on the inhibition of butyrylcholinesterase, studies have shown that that butyrylcholinesterase is a genetically validated drug target and its selective inhibition reduces the formation of β-amyloid plaques.</p> <p>Rationale</p> <p>We previously reported the inhibition of cholinesterases by 2,3-dihydro-1, 5-benzothiazepines, and considered this class of compounds as promising inhibitors for the cure of Alzheimer's disease. One compound from the same series, when substituted with a hydroxy group at C-3 in ring A and 2-thienyl moiety as ring B, showed greater activity against butyrylcholinesterase than to acetylcholinesterase. To provide insight into the binding mode of this compound (Compound A), molecular docking in combination with molecular dynamics simulation of 5000 ps in an explicit solvent system was carried out for both cholinesterases.</p> <p>Conclusion</p> <p>Molecular docking studies revealed that the potential of Compound A to inhibit cholinesterases was attributable to the cumulative effects of strong hydrogen bonds, cationic-π, π-π interactions and hydrophobic interactions. A comparison of the docking results of Compound A against both cholinesterases showed that amino acid residues in different sub-sites were engaged to stabilize the docked complex. The relatively high affinity of Compound A for butyrylcholinesterase was due to the additional hydrophobic interaction between the 2-thiophene moiety of Compound A and Ile69. The involvement of one catalytic triad residue (His438) of butyrylcholinesterase with the 3'-hydroxy group on ring A increases the selectivity of Compound A. C-C bond rotation around ring A also stabilizes and enhances the interaction of Compound A with butyrylcholinesterase. Furthermore, the classical network of hydrogen bonding interactions as formed by the catalytic triad of butyrylcholinesterase is disturbed by Compound A. This study may open a new avenue for structure-based drug design for Alzheimer's disease by considering the 3D-pharmacophoric features of the complex responsible for discriminating these two closely-related cholinesterases.</p

Neuroscience and education: prime time to build the bridge

As neuroscience gains social traction and entices media attention, the notion that education has much to benefit from brain research becomes increasingly popular. However, it has been argued that the fundamental bridge toward education is cognitive psychology, not neuroscience. We discuss four specific cases in which neuroscience synergizes with other disciplines to serve education, ranging from very general physiological aspects of human learning such as nutrition, exercise and sleep, to brain architectures that shape the way we acquire language and reading, and neuroscience tools that increasingly allow the early detection of cognitive deficits, especially in preverbal infants. Neuroscience methods, tools and theoretical frameworks have broadened our understanding of the mind in a way that is highly relevant to educational practice. Although the bridge’s cement is still fresh, we argue why it is prime time to march over it

Recent approaches to novel anti-Alzheimer therapy

Insufficient cholinergic neurotransmission in AD is responsible for a progressive loss of cognition and motor capacities. The cholinergic hypothesis has provided the rationale for the current treatment approaches based on acetylcholinesterase inhibitors. However, recent data focus on the complex nature of AD and disclose the involvement of other neurotransmitters such as serotonin, noradrenalin, dopamine, histamine, excitatory amino acids and neuropeptides among others. Interestingly, recent research has revealed that in severe AD brains the levels of AChE are considerably reduced whereas BuChE activity increases, thus aggravating the toxicity of betaA. In such instances, it is possible that BuChE may be a more suitable target than AChE. Oxidative stress has been implicated in CNS degenerative disorders such as AD and PD. Therefore, owing to their capacity to inhibit oxidative damage, MAOIs are potential candidates as anti-Alzheimer drugs. More recently, a novel drug - TV3326 - was designed, based upon two pharmacophores: the carbamate moiety from rivastigmine, an AChE inhibitor; and the propargyl group from rasagiline, a MAO inhibitor. This drug exhibits cholinesterase and selective brain MAO inhibitory activities, reduces apoptosis and stimulates the processing of APPalpha, hence reducing the possibility of generation of the toxic betaA. Thus, TV3326 may be expected to contribute positively to the cognitive benefits of Alzheimer's patients. Anyhow, the development of drugs with several targets and diverse pharmacological properties may conclusively demonstrate the most beneficial therapy

Synthesis and acetylcholinesterase/butyrylcholin-esterase inhibition activity of 4-amino-2,3-diaryl-5,6,7,8-tetrahydrofuro(and thieno)[2,3-b]quinolines, and 4-amino-5,6,7,8,9-pentahydro-2,3-diphenylcyclohepta[e]furo(and thieno)-[2,3-b]pyridine

The acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibition activities of a series of 4-amino-2,3-diaryl-5,6,7,8-tetrahydrofuro[2,3-b]quinolines (10-12)/4-amino-5,6,7,8-tetrahydro-2,3-diphenylthieno[2,3-b]quinoline (14) and 4-amino-5,6,7,8,9-pentahydro-2,3-diphenylcyclohepta[e]furo[2,3-b]pyridine (13)/4amino-5,6,7,8,9-pentahydro-2,3-phenylcyclohepta[e]thieno[2,3-b]pyridine (15) are described. These compounds are tacrine (THA) analogues which have been prepared either from readily available 2-amino-3-cyano-4,5-diarylfurans (16-18) or from 2-amino-3-cyano-4,5-diphenylthiophene (19), via Friedlander condensation with cyclohexanone or cycloheptanone. These compounds are competitive inhibitors for acetylcholinesterase, the more potent being compound (13) which is threefold less active than tacrine. The butyrylcholinesterase inhibition activity is significant only in compounds 10 and 13, which are ten-fold less active than tacrine. It is found that the products 11 and 12 strongly inhibit acetylcholinesterase, and show excellent selectivity regarding butyrylcholinesterase

Synthesis and acetylcholinesterase/butyrylcholinesterase inhibition activity of new tacrine-like analogues

The synthesis and preliminary results for acetylcholinesterase and butyrylcholinesterase inhibition activity of a series of pyrano[2,3-b]quinolines (2, 3) and benzonaphthyridines (5, 6) derivatives are described. These molecules are tacrine-like analogues which have been prepared from readily available polyfunctionalized ethyl [6-amino-5-cyano-4H-pyrans and 6-amino-5-cyanopyridine s]-3-carboxylates via Friedlander condensation with selected ketone s. These compounds showed moderate acetylcholinesterase inhibition activity, the more potent (2e, 5b) being 6 times less active than tacrine. The butyrylcholinesterase activity of some of these molecules is also discussed. (C) 2001 Elsevier Science Ltd. All rights reserved

1,6-C-H and 1,5-O-Si insertion reactions of alkylidenecarbene derivatives of monosaccharides

A new protocol has been developed for the generation of alkylidenecarbene derivatives of monosaccharides based on the reaction of trimethylsilylazide and Bu2SnO with alpha-cyanomesylates derived from uloses. When this method is applied to conveniently functionalized carbohydrate derivatives it provides novel heterocyclic ring systems by the rare 1,6-C-H or 1,5-O-Si insertion reactions