Interaction of amyloid beta with humanin and acetylcholinesterase is modulated by ATP

Urolithin improves α-synuclein aggregation and DNMT1 expression in rotenone model of Parkinson's disease

α-synuclein aggregation is a key hallmark of Parkinson's disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA). We examined the multi-targeting effects of urolithin (UA, UB, UC, UD, UE, UM5, and UM6) against α-synuclein aggregation using an in-silico and in-vitro approach. For in-silico analysis, several potential targets were selected like 1XQ8 (α-synuclein monomer), 1H1D (catechol-o-methyltransferase), 2BK3 (monoamine oxidase-B), 3IAM (NADH dehydrogenase), 4I5I (Sirtuin-1), and 5WVO [DNA methyltransferase-1], which play key role in α-synuclein aggregation, levodopa degradation, and mitochondrial dysfunction. In protein-protein docking analysis, 5HF9 (acetylcholinesterase, AChE) was found to interact with 1XQ8 dimer, forming a more stable complex with two additional H-bonds and one salt bridge, which indicates AChE's role as a nucleator in α-synuclein aggregation. In ligand docking and molecular dynamic studies, urolithin-A (UA) formed a more stable complex with 1XQ8, 4I5I, and 5WVO compared to specific inhibitor 1XQ8-ZPD2 and specific activator 4I5I-resveratrol. While other urolithins (UE, UM5, UC, and UD) displayed a more stable complex with 5HF9, 2BK3, 1H1D, and 3IAM compared to specific inhibitor 5HF9-physostigmine, 2BK3-selegiline, 1H1D-BIA, and specific activator 3IAM-resveratrol complexes, respectively. The blood-brain barrier permeability of UA (QPlogBB: -0.97) was predicted to be more than levodopa (QPlogBB: -1.44) and less than rotenone (QPlogBB: 0.08). DNMT1 inhibitor (5-Aza-dC) and rotenone robustly decreased the DNMT1 and α-synuclein expression in Neuro 2 A cells which was significantly reversed by UA treatment at 31.25 µM concentration. These findings indicate the potential of urolithins, specifically UA, UC, UD, UE, and UM5 against α-synuclein aggregation.

Queuine as a potential multi-target drug for alzheimer's disease: insights from protein dynamics

Alzheimer's disease (AD) is a neurodegenerative disorder with a complex pathogenesis. One promising approach to treating AD is simultaneously targeting multiple aspects of the disease using a multi-target drug (MTD). In this study, multi-target drug (MTD) potential of the nutraceutical molecule Queuine was explored using molecular docking and molecular dynamics (MD) simulations with five different protein targets engaged in AD: AChE, beta-site amyloid precursor protein cleaving enzyme-1 (BACE-1), N-methyl-D-aspartate receptor (NMDAR), monoamine oxidase A (MAO-A), and Synapsin III. Queuine revealed significant binding affinities, the docking scores being -10.1, -5.97, -5.63, -8.40, and -10.56 kcal/mol for AChE, BACE-1, NMDAR, MAO-A, and Synapsin III, respectively. MD simulations showed that Queuine formed stable complexes and preserved its stability throughout the simulation, the backbone fluctuations remaining within 2.5 Å specifically in the case of the BACE-1. Elastic network model simulations and principal component analysis were carried out to illustrate the dynamics of the protein systems. Significant hinge-bending and twisting-type motions that may be relevant to function were observed around the dimerization interfaces or binding sites. Structural clustering based on PCA analysis and cross-correlation maps demonstrated that Queuine binding altered the protein dynamics more drastically in the case of highly mobile proteins NMDAR and MAO-A. We propose that the neuroprotective effect of Queuine may stem from its prominent inhibitory action on enzymes BACE-1 and AChE. Our results suggest that Queuine may serve as a promising MTD candidate for the treatment of AD.Communicated by Ramaswamy H. Sarma.

Indole and Coumarin Derivatives Targeting EEF2K in Aβ Folding Reporter Cells

Misfolding and accumulation of amyloid-β (Aβ) in the brains of patients with Alzheimer's disease (AD) lead to neuronal loss through various mechanisms, including the downregulation of eukaryotic elongation factor 2 (EEF2) protein synthesis signaling. This study investigated the neuroprotective effects of indole and coumarin derivatives on Aβ folding and EEF2 signaling using SH-SY5Y cells expressing Aβ-green fluorescent protein (GFP) folding reporter. Among the tested compounds, two indole (NC009-1, -6) and two coumarin (LM-021, -036) derivatives effectively reduced Aβ misfolding and associated reactive oxygen species (ROS) production. Additionally, these compounds decreased acetylcholinesterase and caspase-3/-6 activities while promoting neurite outgrowth. NC009-1 increased active phosphorylation of extracellular-signal regulated kinase (ERK) (T202/Y204), leading to an increase in inactive eukaryotic elongation factor 2 kinase (EEF2K) phosphorylation (S366). LM-021 decreased the active phosphorylation of AMP-activated protein kinase (AMPK) (T172) and EEF2K (S398), while LM-036 exhibited dual effects, increasing inactive phosphorylation and decreasing active phosphorylation of EEF2K. These changes in EEF2K phosphorylation led to decreased EEF2K activity and a subsequent reduction in inactive phosphorylation of EEF2 (T56). This cascade further promoted the phosphorylation of transcription factor cAMP-response-element binding protein (CREB) (S133) and the expression of brain-derived neurotrophic factor (BDNF), and reduced BCL-2 associated X-protein (BAX)/B-cell lymphoma 2 (BCL2) ratio. Knockdown of EEF2 abolished the effects of NC009-1, LM-021, and LM-036 on CREB phosphorylation, BDNF expression, caspase-3 activity, and neurite outgrowth. These findings demonstrate that NC009-1, LM-021, and LM-036 exert their neuroprotective effects through modulation of EEF2K signaling, highlighting their potentials as therapeutic candidates for AD.

Amyloid Beta Leads to Decreased Acetylcholine Levels and Non-Small Cell Lung Cancer Cell Survival via a Mechanism That Involves p38 Mitogen-Activated Protein Kinase and Protein Kinase C in a p53-Dependent and -Independent Manner

Several studies have shown an inverse correlation between the likelihood of developing a neurodegenerative disorder and cancer. We previously reported that the levels of amyloid beta (Aβ), at the center of Alzheimer's disease pathophysiology, are regulated by acetylcholinesterase (AChE) in non-small cell lung cancer (NSCLC). Here, we examined the effect of Aβ or its fragments on the levels of ACh in A549 (p53 wild-type) and H1299 (p53-null) NSCLC cell media. ACh levels were reduced by cell treatment with Aβ 1-42, Aβ 1-40, Aβ 1-28, and Aβ 25-35. AChE and p53 activities increased upon A549 cell treatment with Aβ, while knockdown of p53 in A549 cells increased ACh levels, decreased AChE activity, and diminished the Aβ effects. Aβ increased the ratio of phospho/total p38 MAPK and decreased the activity of PKC. Inhibiting p38 MAPK reduced the activity of p53 in A549 cells and increased ACh levels in the media of both cell lines, while opposite effects were found upon inhibiting PKC. ACh decreased the activity of p53 in A549 cells, decreased p38 MAPK activity, increased PKC activity, and diminished the effect of Aβ on those activities. Moreover, the negative effect of Aβ on cell viability was diminished by cell co-treatment with ACh.

The role of leptin in regulation of the soluble amyloid precursor protein α (sAPPα) levels in lung cancer cell media

Previously, we found that the levels of soluble amyloid precursor protein α (sAPPα) are regulated, in part, by acetylcholinesterase (AChE) in human A549 (p53 wild-type) and H1299 (p53-null) NSCLC cell lines. In this study, we found regulation of sAPPα levels in the media by leptin, a widely recognized obesity-associated adipokine that has recently been shown to play a possible role in cancer signaling. Increased levels of sAPPα, that were accompanied by lower Aβ40/42 levels in the media of A549 and H1299 cells, were detected upon cell incubation with leptin. Conversely, knockdown of leptin or its receptor led to reduced levels of sAPPα and increased levels of Aβ40/42 in the media of A549 and H1299 cells, suggesting that leptin likely shifts APP processing toward the non-amyloidogenic pathway. A549 cell treatment with leptin increased acetylcholine levels and blocked the activities of AChE and p53. Treatment with leptin resulted in increased activation of PKC, ERK1/2, PI3K, and the levels of sAPPα, effects that were reversed by treatment with kinase inhibitors and/or upon addition of AChE to A549 and H1299 cell media. Cell viability increased by treatment of A549 and H1299 cells with leptin and decreased upon co-treatment with AChE and/or inhibitors targeting PKC, ERK1/2, and PI3K. This study is significant as it provides evidence for a likely carcinogenic role of leptin in NSCLC cells via upregulation of sAPPα levels in the media, and highlights the importance of targeting leptin as a potential therapeutic strategy for NSCLC treatment.

Regulation of Vascular Endothelial Growth Factor Signaling by Nicotine in a Manner Dependent on Acetylcholine-and/or β-Adrenergic-Receptors in Human Lung Cancer Cells

Simple Summary

Nicotine, a highly addictive component in cigarette smoke, facilitates tumorigenesis and the accelerated development of non-small cell lung cancer (NSCLC), which is known to account for ~80% of all lung cancer cases. This study sheds light on how the nicotine treatment of NSCLC cells regulates vascular endothelial growth factor (VEGF) signaling, known to be important in the progression of vascular disease and cancer, by acting through nicotinic acetylcholine receptors and by leading to the activation of β-adrenergic receptors through increased levels of the stress neurotransmitters, norepinephrine/noradrenaline, and epinephrine/adrenaline. Nicotine-induced activation of VEGF promoted the function of proteins involved in increased cell survival and suppressed the function of a crucial tumor suppressor, blocking cell death. This work expands our scientific knowledge of mechanisms employed by nicotine in regulating VEGF signaling in a manner dependent on the acetylcholine and/or β-adrenergic receptors, leading to lung cancer cell survival, and also provides significant insights into novel future therapeutic strategies to combat lung cancer.

Abstract

In addition to binding to nicotinic acetylcholine receptors (nAChRs), nicotine is known to regulate the β-adrenergic receptors (β-ARs) promoting oncogenic signaling. Using A549 (p53 wild-type) and H1299 (p53-null) lung cancer cells, we show that nicotine treatment led to: increased adrenaline/noradrenaline levels, an effect blocked by treatment with the α7nAChR inhibitor (α-BTX) but not by the β-blocker (propranolol) or the α4β2nAChR antagonist (DhβE); decreased GABA levels in A549 and H1299 cell media, an effect blocked by treatment with DhβE; increased VEGF levels and PI3K/AKT activities, an effect diminished by cell co-treatment with α-BTX, propranolol, and/or DhβE; and inhibited p53 activity in A549 cells, that was reversed, upon cell co-treatment with α-BTX, propranolol, and/or DhβE or by VEGF immunodepletion. VEGF levels increased upon cell treatment with nicotine, adrenaline/noradrenaline, and decreased with GABA treatment. On the other hand, the p53 activity decreased in A549 cells treated with nicotine, adrenaline/noradrenaline and increased upon cell incubation with GABA. Knockdown of p53 led to increased VEGF levels in the media of A549 cells. The addition of anti-VEGF antibodies to A549 and H1299 cells decreased cell viability and increased apoptosis; blocked the activities of PI3K, AKT, and NFκB in the absence or presence of nicotine; and resulted in increased p53 activation in A549 cells. We conclude that VEGF can be upregulated via α7nAChR and/or β-ARs and downregulated via GABA and/or p53 in response to the nicotine treatment of NSCLC cells.

Regulation of Soluble E-Cadherin Signaling in Non-Small-Cell Lung Cancer Cells by Nicotine, BDNF, and β-Adrenergic Receptor Ligands

The ectodomain of the transmembrane protein E-cadherin can be cleaved and released in a soluble form referred to as soluble E-cadherin, or sE-cad, accounting for decreased E-cadherin levels at the cell surface. Among the proteases implicated in this cleavage are matrix metalloproteases (MMP), including MMP9. Opposite functions have been reported for full-length E-cadherin and sE-cad. In this study, we found increased MMP9 levels in the media of two non-small cell lung cancer (NSCLC) cell lines, A549 and H1299, treated with BDNF, nicotine, or epinephrine that were decreased upon cell treatment with the β-adrenergic receptor blocker propranolol. Increased MMP9 levels correlated with increased sE-cad levels in A549 cell media, and knockdown of MMP9 in A549 cells led to downregulation of sE-cad levels in the media. Previously, we reported that A549 and H1299 cell viability increased with nicotine and/or BDNF treatment and decreased upon treatment with propranolol. In investigating the function of sE-cad, we found that immunodepletion of sE-cad from the media of A549 cells untreated or treated with BDNF, nicotine, or epinephrine reduced activation of EGFR and IGF-1R, decreased PI3K and ERK1/2 activities, increased p53 activation, decreased cell viability, and increased apoptosis, while no effects were found using H1299 cells under all conditions tested.

Phosphorylation of IGFBP-3 by Casein Kinase 2 Blocks Its Interaction with Hyaluronan, Enabling HA-CD44 Signaling Leading to Increased NSCLC Cell Survival and Cisplatin Resistance

Cisplatin is a platinum agent used in the treatment of non-small cell lung cancer (NSCLC). Much remains unknown regarding the basic operative mechanisms underlying cisplatin resistance in NSCLC. In this study, we found that phosphorylation of IGFBP-3 by CK2 (P-IGFBP-3) decreased its binding to hyaluronan (HA) but not to IGF-1 and rendered the protein less effective at reducing cell viability or increasing apoptosis than the non-phosphorylated protein with or without cisplatin in the human NSCLC cell lines, A549 and H1299. Our data suggest that blocking CD44 signaling augmented the effects of cisplatin and that IGFBP-3 was more effective at inhibiting HA-CD44 signaling than P-IGFBP-3. Blocking CK2 activity and HA-CD44 signaling increased cisplatin sensitivity and more effectively blocked the PI3K and AKT activities and the phospho/total NFκB ratio and led to increased p53 activation in A549 cells. Increased cell sensitivity to cisplatin was observed upon co-treatment with inhibitors targeted against PI3K, AKT, and NFκB while blocking p53 activity decreased A549 cell sensitivity to cisplatin. Our findings shed light on a novel mechanism employed by CK2 in phosphorylating IGFBP-3 and increasing cisplatin resistance in NSCLC. Blocking phosphorylation of IGFBP-3 by CK2 may be an effective strategy to increase NSCLC sensitivity to cisplatin.

Opposing Roles of IGFBP-3 and Heparanase in Regulating A549 Lung Cancer Cell Survival

In this study, we examined the roles of heparanase and IGFBP-3 in regulating A549 and H1299 non-small-cell lung cancer (NSCLC) survival. We found that H1299 cells, known to be p53-null with no expression of IGFBP-3, had higher heparanase levels and activity and higher levels of heparan sulfate (HS) in the media compared to the media of A549 cells. Inhibiting heparanase activity or its expression using siRNA had no effect on the levels of IGFBP-3 in the media of A549 cells, reduced the levels of soluble HS fragments, and led to decreased interactions between IGFBP-3 and HS in the media. HS competed with HA for binding to IGFBP-3 or IGFBP-3 peptide (²¹⁵-KKGFYKKKQCRPSKGRKR-²³²) but not the mutant peptide (K228AR230A). HS abolished the cytotoxic effects of IGFBP-3 but not upon blocking HA-CD44 signaling with the anti-CD44 antibody (5F12). Blocking HA-CD44 signaling decreased the levels of heparanase in the media of both A549 and H1299 cell lines and increased p53 activity and the levels of IGFBP-3 in A549 cell media. Knockdown of p53 led to increased heparanase levels and reduced IGFBP-3 levels in A549 cell media while knockdown of IGFBP-3 in A549 cells blocked p53 activity and increased heparanase levels in the media.

Multitargeted Molecular Docking and Dynamic Simulation Studies of Bioactive Compounds from Rosmarinus officinalis against Alzheimer's Disease

Alzheimer's disease (AD) has been associated with the hallmark features of cholinergic dysfunction, amyloid beta (Aβ) aggregation and impaired synaptic transmission, which makes the associated proteins, such as β-site amyloid precursor protein cleaving enzyme 1 (BACE I), acetylcholine esterase (AChE) and synapsin I, II and III, major targets for therapeutic intervention. The present study investigated the therapeutic potential of three major phytochemicals of Rosmarinus officinalis, ursolic acid (UA), rosmarinic acid (RA) and carnosic acid (CA), based on their binding affinity with AD-associated proteins. Detailed docking studies were conducted using AutoDock vina followed by molecular dynamic (MD) simulations using Amber 20. The docking analysis of the selected molecules showed the binding energies of their interaction with the target proteins, while MD simulations comprising root mean square deviation (RMSD), root mean square fluctuation (RMSF) and molecular mechanics/generalized born surface area (MM/GBSA) binding free energy calculations were carried out to check the stability of bound complexes. The drug likeness and the pharmacokinetic properties of the selected molecules were also checked through the Lipinski filter and ADMETSAR analysis. All these bioactive compounds demonstrated strong binding affinity with AChE, BACE1 and synapsin I, II and III. The results showed UA and RA to be potential inhibitors of AChE and BACE1, exhibiting binding energies comparable to those of donepezil, used as a positive control. The drug likeness and pharmacokinetic properties of these compounds also demonstrated drug-like characteristics, indicating the need for further in vitro and in vivo investigations to ascertain their therapeutic potential for AD.

Regulation of the Soluble Amyloid Precursor Protein α (sAPPα) Levels by Acetylcholinesterase and Brain-Derived Neurotrophic Factor in Lung Cancer Cell Media

In comparing two human lung cancer cells, we previously found lower levels of acetylcholinesterase (AChE) and intact amyloid-β40/42 (Aβ), and higher levels of mature brain-derived neurotrophic factor (mBDNF) in the media of H1299 cells as compared to A549 cell media. In this study, we hypothesized that the levels of soluble amyloid precursor protein α (sAPPα) are regulated by AChE and mBDNF in A549 and H1299 cell media. The levels of sAPPα were higher in the media of H1299 cells. Knockdown of AChE led to increased sAPPα and mBDNF levels and correlated with decreased levels of intact Aβ40/42 in A549 cell media. AChE and mBDNF had opposite effects on the levels of Aβ and sAPPα and were found to operate through a mechanism involving α-secretase activity. Treatment with AChE decreased sAPPα levels and simultaneously increased the levels of intact Aβ40/42 suggesting a role of the protein in shifting APP processing away from the non-amyloidogenic pathway and toward the amyloidogenic pathway, whereas treatment with mBDNF led to opposite effects on those levels. We also show that the levels of sAPPα are regulated by protein kinase C (PKC), extracellular signal-regulated kinase (ERK)1/2, phosphoinositide 3 Kinase (PI3K), but not by protein kinase A (PKA).

Insights into the Mechanisms of Action of Proanthocyanidins and Anthocyanins in the Treatment of Nicotine-Induced Non-Small Cell Lung Cancer

In traditional medicine, different parts of plants, including fruits, have been used for their anti-inflammatory and anti-oxidative properties. Plant-based foods, such as fruits, seeds and vegetables, are used for therapeutic purposes due to the presence of flavonoid compounds. Proanthocyanidins (PCs) and anthocyanins (ACNs) are the major distributed flavonoid pigments in plants, which have therapeutic potential against certain chronic diseases. PCs and ACNs derived from plant-based foods and/or medicinal plants at different nontoxic concentrations have shown anti-non-small cell lung cancer (NSCLC) activity in vitro/in vivo models through inhibiting proliferation, invasion/migration, metastasis and angiogenesis and by activating apoptosis/autophagy-related mechanisms. However, the potential mechanisms by which these compounds exert efficacy against nicotine-induced NSCLC are not fully understood. Thus, this review aims to gain insights into the mechanisms of action and therapeutic potential of PCs and ACNs in nicotine-induced NSCLC.

Differences in the Relative Abundance of ProBDNF and Mature BDNF in A549 and H1299 Human Lung Cancer Cell Media

Brain-derived neurotrophic factor (BDNF), a member of the neurotrophin family, has been linked to several human malignancies and shown to promote tumorigenesis. The purpose of this study was to explore the relative abundance of pro-brain-derived neurotrophic factor (proBDNF) and mature BDNF (mBDNF) in A549 (p53 wild-type) and H1299 (p53-null) lung cancer cell media. Higher levels of proBDNF were detected in the media of A549 cells than in H1299 cell media. Using inhibitors, we found that the levels of proBDNF and mBDNF in the media are likely regulated by PI3K, AKT, and NFκB. However, the largest change in these levels resulted from MMP2/9 inhibition. Blocking p53 function in A549 cells resulted in increased mBDNF and decreased proBDNF, suggesting a role for p53 in regulating these levels. The ratio of proBDNF/mBDNF was not affected by MMP2 knockdown but increased in the media of both cell lines upon knockdown of MMP9. Downregulation of either MMP2 or MMP9 by siRNA showed that MMP9 siRNA treatment of either A549 or H1299 cells resulted in decreased cell viability and increased apoptosis, an effect diminished upon the same treatment with proBDNF immunodepleted media, suggesting that MMP9 regulates the cytotoxic effects induced by proBDNF in lung cancer cells.

Regulation of amyloid-β levels by matrix metalloproteinase-2/9 (MMP2/9) in the media of lung cancer cells

In this study, we set out to identify regulators of intact amyloid-β40/42 (Aβ) levels in A549 (p53 wild-type) and H1299 (p53-null) lung cancer cell media. Higher Aβ levels were detected in the media of A549 than H1299 cells without or with treatment with 4-methylumbelliferone (4-MU) and/or the anti-CD44 antibody (5F12). Using inhibitors, we found that PI3K, AKT, and NFκB are likely involved in regulating Aβ levels in the media. However, increased Aβ levels that more closely resembled those found upon 4-MU co-treatment resulted from MMP2/9 inhibition, suggesting that MMP2/9 maybe the main contributors to regulation of Aβ levels in the media. Differences in Aβ levels might be accounted for, in part, by p53 since blocking p53 function in A549 cells resulted in decreased Aβ levels, increased MMP2/9 levels, increased PI3K/AKT activities and the phospho/total NFκB ratio. Using siRNA targeted against MMP2 or MMP9, we found increased Aβ levels in the media, however, MMP2 knockdown led to Aβ levels closely mimicking those detected by co-treatment with 4-MU. Cell viability or apoptosis upon treatment with either MMP2 or MMP9 siRNA along with Aβ immunodepletion, showed that MMP2 is the predominant regulator of the cytotoxic effects induced by Aβ in lung cancer cells.