Project description:Amphetamine and its derivatives exhibit a wide range of pharmacological activities, including psychostimulant, hallucinogenic, entactogenic, anorectic, or antidepressant effects. The mechanisms of action underlying these effects are usually related to the ability of the different amphetamines to interact with diverse monoamine transporters or receptors. Moreover, many of these compounds are also potent and selective monoamine oxidase inhibitors. In the present work, we review how structural modifications on the aromatic ring, the amino group and/or the aliphatic side chain of the parent scaffold, modulate the enzyme inhibitory properties of hundreds of amphetamine derivatives. Furthermore, we discuss how monoamine oxidase inhibition might influence the pharmacology of these compounds.
Project description:Monoamine oxidase A (MAOA) is an important mitochondria-bound enzyme that catalyzes the oxidative deamination of monoamine neurotransmitters. Accumulating evidence suggests a significant association of increased MAOA expression and advanced high-grade prostate cancer (PCa) progression and metastasis. Herein, a series of novel conjugates combining the MAOA inhibitor isoniazid (INH) and tumor-targeting near-infrared (NIR) heptamethine cyanine dyes were designed and synthesized. The synthesized compounds G1⁻G13 were evaluated in vitro for their cytotoxicity against PC-3 cells using the MTT assay, and molecular docking studies were performed. Results showed that most tested compounds exhibited improved antitumor efficacy compared with INH. Moreover, conjugates G10 and G11 showed potent anticancer activity with IC50 values (0.85 and 0.4 μM respectively) comparable to that of doxorubicin (DOX). This may be attributable to the preferential accumulation of these conjugates in tumor cells. G10, G11, and G12 also demonstrated moderate MAOA inhibitory activities. This result and the results of molecular docking studies were consistent with their cytotoxicity activities. Taken together, these data suggest that a combination of the MAOA inhibitor INH with tumor-targeting heptamethine cyanine dyes may prove to be a highly promising tool for the treatment of advanced prostate cancer.
Project description:Monoamine oxidases (MAO) are a valuable class of mitochondrial enzymes with a critical role in neuromodulation. In this study, we investigated the effect of natural MAO inhibitors on novel environment-induced anxiety by using the zebrafish novel tank test (NTT). Because zebrafish spend more time at the bottom of the tank when they are anxious, anxiolytic compounds increase the time zebrafish spend at the top of the tank and vice versa. Using this paradigm, we found that harmane, norharmane, and 1,2,3,4-tetrahydroisoquinoline (TIQ) induce anxiolytic-like effects in zebrafish, causing them to spend more time at the top of the test tank and less time at the bottom. 2,3,6-trimethyl-1,4-naphtoquinone (TMN) induced an interesting mix of both anxiolytic- and anxiogenic-like effects during the first and second halves of the test, respectively. TIQ was unique in having no observable effect on general movement. Similarly, a reference MAO inhibitor clorgyline-but not pargyline-increased the time spent at the top in a concentration-dependent manner. We also demonstrated that the brain bioavailability of these compounds are high based on the ex vivo bioavailability assay and in silico prediction models, which support the notion that the observed effects on anxiety-like behavior in zebrafish were most likely due to the direct effect of these compounds in the brain. This study is the first investigation to demonstrate the anxiolytic-like effects of MAO inhibitors on novel environment-induced anxiety in zebrafish.
Project description:Monoamine oxidase A (MAO-A), a mitochondrial enzyme that degrades monoamines including neurotransmitters, is highly expressed in basal cells of the normal human prostatic epithelium and in poorly differentiated (Gleason grades 4 and 5), aggressive prostate cancer (PCa). Clorgyline, an MAO-A inhibitor, induces secretory differentiation of normal prostate cells. We systematically assessed gene expression changes induced by clorgyline in E-CA cells using high-density oligonucleotide microarrays. Genes differentially expressed in treated and control cells were identified by Significance Analysis of Microarrays. Expression of genes of interest was validated by quantitative real-time polymerase chain reaction.
Project description:Monoamine oxidase A (MAO-A), a mitochondrial enzyme that degrades monoamines including neurotransmitters, is highly expressed in basal cells of the normal human prostatic epithelium and in poorly differentiated (Gleason grades 4 and 5), aggressive prostate cancer (PCa). Clorgyline, an MAO-A inhibitor, induces secretory differentiation of normal prostate cells. We systematically assessed gene expression changes induced by clorgyline in E-CA cells using high-density oligonucleotide microarrays. Genes differentially expressed in treated and control cells were identified by Significance Analysis of Microarrays. Expression of genes of interest was validated by quantitative real-time polymerase chain reaction. time series design
Project description:BackgroundMonoamine oxidase A (MAOA) is best known for its role in neuro-transmitter regulation. Monoamine oxidase inhibitors are used to treat atypical depression. MAOA is highly expressed in high grade prostate cancer and modulates tumorigenesis and progression in prostate cancer. Here, we investigated the potential role of MAOA inhibitors (MAOAIs) in relation to the androgen receptor (AR) pathway and resistance to antiandrogen treatment in prostate cancer.MethodsWe examined MAOA expression and the effect of MAOI treatment in relation to AR-targeted treatments using the LNCaP, C4-2B, and 22Rv1 human prostate cancer cell lines. MAOA, AR-full length (AR-FL), AR splice variant 7 (AR-V7), and PSA expression was evaluated in the presence of MAOAIs (clorgyline, phenelzine), androgenic ligand (R1881), and antiandrogen (enzalutamide) treatments. An enzalutamide resistance cell line was generated to test the effect of MAOAI treatment in this model.ResultsWe observed that MAOAIs, particularly clorgyline and phenelzine, were effective at decreasing MAOA activity in human prostate cancer cells. MAOAIs significantly decreased growth of LNCaP, C4-2B, and 22Rv1 cells and produced additive growth inhibitory effects when combined with enzalutamide. Clorgyline decreased expression of AR-FL and AR-V7 in 22Rv1 cells and was effective at decreasing growth of an enzalutamide-resistant C4-2B cell line with increased AR-V7 expression.ConclusionsMAOAIs decrease growth and proliferation of androgen-sensitive and castration-resistant prostate cancer cells. Clorgyline, in particular, decreases expression of AR-FL and AR-V7 expression and decreases growth of an enzalutamide-resistant cell line. These findings provide preclinical validation of MAOA inhibitors either alone or in combination with antiandrogens for therapeutic intent in patients with advanced forms of prostate cancer.
Project description:BackgroundMonoamine oxidase inhibitors (MAOIs) are being developed for major depressive disorder, Alzheimer's, and Parkinson's Disease. Newer MAOIs have minimal sensitivity to tyramine, but a key limitation for optimizing their development is that standards for in vivo monoamine oxidase-A (MAO-A) occupancy in humans are not well established. The objectives were to determine the dose-occupancy relationship of moclobemide and the occupancy of phenelzine at typical clinical dosing.MethodsMajor depressive episode (MDE) subjects underwent [(11)C]harmine positron emission tomography scanning prior to and following 6 weeks of treatment with moclobemide or phenelzine.ResultsMean brain MAO-A occupancies were 74.23±8.32% for moclobemide at 300-600 mg daily (n = 11), 83.75±5.52% for moclobemide at 900-1200 mg daily (n = 9), and 86.82±6.89% for phenelzine at 45-60 mg daily (n = 4). The regional dose-occupancy relationship of moclobemide fit a hyperbolic function [F(x) = a(x/[b + x]); F(1,18) = 5.57 to 13.32, p = 0.002 to 0.03, mean 'a': 88.62±2.38%, mean 'b': 69.88±4.36 mg]. Multivariate analyses of variance showed significantly greater occupancy of phenelzine (45-60mg) and higher-dose moclobemide (900-1200 mg) compared to lower-dose moclobemide [300-600 mg; F(7,16) = 3.94, p = 0.01].ConclusionsThese findings suggest that for first-line MDE treatment, daily moclobemide doses of 300-600mg correspond to a MAO-A occupancy of 74%, whereas for treatment-resistant MDE, either phenelzine or higher doses of moclobemide correspond to a MAO-A occupancy of at least 84%. Therefore, novel MAO inhibitor development should aim for similar thresholds. The findings provide a rationale in treatment algorithm design to raise moclobemide doses to inhibit more MAO-A sites, but suggest switching from high-dose moclobemide to phenelzine is best justified by binding to additional targets.
Project description:Halogens have been reported to play a major role in the inhibition of monoamine oxidase (MAO), relating to diverse cognitive functions of the central nervous system. Pyrazoline/halogenated pyrazolines were investigated for their inhibitory activities against human monoamine oxidase-A and -B. Halogen substitutions on the phenyl ring located at the fifth position of pyrazoline showed potent MAO-B inhibition. Compound 3-(4-ethoxyphenyl)-5-(4-fluorophenyl)-4,5-dihydro-1H-pyrazole (EH7) showed the highest potency against MAO-B with an IC50 value of 0.063 µM. The potencies against MAO-B were increased in the order of -F (in EH7) > -Cl (EH6) > -Br (EH8) > -H (EH1). The residual activities of most compounds for MAO-A were > 50% at 10 µM, except for EH7 and EH8 (IC50 = 8.38 and 4.31 µM, respectively). EH7 showed the highest selectivity index (SI) value of 133.0 for MAO-B, followed by EH6 at > 55.8. EH7 was a reversible and competitive inhibitor of MAO-B in kinetic and reversibility experiments with a Ki value of 0.034 ± 0.0067 µM. The molecular dynamics study documented that EH7 had a good binding affinity and motional movement within the active site with high stability. It was observed by MM-PBSA that the chirality had little effect on the overall binding of EH7 to MAO-B. Thus, EH7 can be employed for the development of lead molecules for the treatment of various neurodegenerative disorders.
Project description:Neuropsychiatric disorders, such as Alzheimer's disease (AD), Parkinson's disease (PD) and depression, have seriously inconvenienced the lives of patients. Growing evidence indicates that these diseases are closely related to the monoamine oxidase (MAO) enzyme, making it an attractive target for the exploitation of potent MAO inhibitors (MAOIs) with high selectivity and low side effects. Although various MAOIs have been discovered, the discovery of an ideal MAOI is not an easy task. In this review, we discuss the currently available rational design strategies for obtaining ideal MAOIs, including ligand-based and receptor-based design strategies, and these strategies were further illustrated with the aid of specific examples from the recent literature. To better understanding the biological activity of MAO, we also highlight the binding modes of typical inhibitors against MAO. Besides, advanced strategies for finding upcoming potent MAOIs were prospected.