Aldehyde Dehydrogenase Enzymes Research Articles

Chemoproteomic Profiling of Signaling Metabolite Fructose-1,6-Bisphosphate Interacting Proteins in Living Cells.

Fructose-1,6-bisphosphate (FBP), a cellular endogenous sugar metabolite in the glycolytic pathway, has recently been reported to act as a signaling molecule to regulate various cellular events through the engagement of important proteins. Though tremendous progress has been made in identifying specific FBP-protein interactions, the comprehensive identification of FBP-interacting proteins and their regulatory mechanisms remains largely unexplored. Here, we describe a concise synthetic approach for the scalable preparation of a photoaffinity FBP probe that enables the quantitative chemoproteomic profiling of FBP-protein interactions based on photoaffinity labeling (PAL) directly in living cells. Using such a protocol, we captured known FBP targets including PKM2 and MDH2. Furthermore, among unknown FBP-interacting proteins, we identified a mitochondrial metabolic enzyme aldehyde dehydrogenase 2 (ALDH2), against which FBP showed inhibitory activity and resulted in cellular ROS upregulation accompanied by mitochondrial fragmentation. Our findings disclosed a new mode of glucose signaling mediating by the FBP-ALDH2-ROS axis.

Effectiveness of genetic feedback on alcohol metabolism to reduce alcohol consumption in young adults: an open-label randomized controlled trial

BackgroundIt is unclear whether brief interventions using the combined classification of alcohol-metabolizing enzymes aldehyde dehydrogenase 2 (ALDH2) and alcohol dehydrogenase 1B (ADH1B) together with behavioral changes in alcohol use can reduce excessive alcohol consumption. This study aimed to examine the effects of a brief intervention based on the screening of ALDH2 and ADH1B gene polymorphisms on alcohol consumption in Japanese young adults.MethodsIn this open-label randomized controlled trial, we enrolled adults aged 20–30 years who had excessive drinking behavior (average amount of alcohol consumed: men, ≥ 4 drinks/per day and women, ≥ 2 drinks/per day; 1 drink = 10 g of pure alcohol equivalent). Participants were randomized into intervention or control group using a simple random number table. The intervention group underwent saliva-based genotyping of alcohol-metabolizing enzymes (ALDH2 and ADH1B), which were classified into five types. A 30-min in-person or online educational counseling was conducted approximately 1 month later based on genotyping test results and their own drinking records. The control group received traditional alcohol education. Average daily alcohol consumption was calculated based on the drinking diary, which was recorded at baseline and at 3 and 6 months of follow-up. The primary endpoint was average daily alcohol consumption, and the secondary endpoints were the alcohol-use disorder identification test for consumption (AUDIT-C) score and behavioral modification stages assessed using a transtheoretical model.ResultsParticipants were allocated to the intervention (n = 100) and control (n = 96) groups using simple randomization. Overall, 28 (29.2%) participants in the control group and 21 (21.0%) in the intervention group did not complete the follow-up. Average alcohol consumption decreased significantly from baseline to 3 and 6 months in the intervention group but not in the control group. The reduction from baseline alcohol consumption values and AUDIT-C score at 3 months were greater in the intervention group than in the control group (p < 0.001). In addition, the behavioral modification stages were significantly changed by the intervention (p < 0.001).ConclusionsGenetic testing for alcohol-metabolizing enzymes and health guidance on type-specific excessive drinking may be useful for reducing sustained average alcohol consumption associated with behavioral modification.Trial registrationR000050379, UMIN000044148, Registered on June 1, 2021.

Biological evaluation of levofloxacin and its thionated derivatives: antioxidant activity, aldehyde dehydrogenase enzyme inhibition, and cytotoxicity on A549 cell line.

Levofloxacin (LVX) is among the fluoroquinolones antibiotics that has also been studied in vitro and in vivo for its anticancer effects. In this study, we used LVX and novel LVX thionated derivatives; compounds 2 and 3, to evaluate their antioxidant activity, aldehyde dehydrogenase (ALDH) enzymes activity inhibition, and anticancer activity. Combination treatments with doxorubicin (DOX) were investigated as well. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay was used to determine the antioxidant activity. The NADH fluorescence spectrophotometric activity assay was used to determine the ALDH inhibitory effects. Resazurin dye method was applied for cell viability assays. Molecular Operating Environment software was used for the molecular docking experiments. Compared to ascorbic acid, DPPH assay showed that compound 3 had the highest antioxidant activity among the tested compounds with approximately 35% scavenging activity. On ALDH enzymes, compound 3 showed a significant ALDH activity inhibition compared to compound 2 at 200 µM. The IC50 values for the tested compounds were approximately 100 µM on A549 cell line, a non-small cell lung cancer (NSCLC) cell line. However, significant enhancement of cytotoxicity and reduction of IC50 values were observed by combining DOX and synergism was achieved with LVX with a combination index value of 0.4. The molecular docking test showed a minimum binding energy with a good affinity for compound 3 towards ALDH enzymes. Thionated LVX derivatives, may be repurposed for NSCLC therapy in combination with DOX, taking into account the antioxidant activity, ALDH activity inhibition, and the molecular docking results of compound 3.

Contribution of a C-Terminal Extension to the Substrate Affinity and Oligomeric Stability of Aldehyde Dehydrogenase from Thermus thermophilus HB27.

Aldehyde dehydrogenase enzymes (ALDHs) are widely studied for their roles in disease propagation and cell metabolism. Their use in biocatalysis applications, for the conversion of aldehydes to carboxylic acids, has also been recognized. Understanding the structural features and functions of both prokaryotic and eukaryotic ALDHs is key to uncovering novel applications of the enzyme and probing its role in disease propagation. The thermostable enzyme ALDHTt originating fromThermus thermophilus, strain HB27, possesses a unique extension of its C-terminus, which has been evolutionarily excluded from mesophilic counterparts and other thermophilic enzymes in the same genus. In this work, the thermophilic adaptation is studied by the expression and optimized purification of mutant ALDHTt-508, with a 22-amino acid truncation of the C-terminus. The mutant shows increased activity throughout production compared to native ALDHTt, indicating an opening of the active site upon C-terminus truncation and giving rationale into the evolutionary exclusion of the C-terminal extension from similar thermophilic and mesophilic ALDH proteins. Additionally, the C-terminus is shown to play a role in controlling substrate specificity of native ALDH, particularly in excluding catalysis of certain large and certain aromatic ortho-substituted aldehydes, as well as modulating the protein's pH tolerance by increasing surface charge. Dynamic light scattering and size-exclusion HPLC methods are used to show the role of the C-terminus in ALDHTt oligomeric stability at the cost of catalytic efficiency. Studying the aggregation rate of ALDHTt with and without a C-terminal extension leads to the conclusion that ALDHTt follows a monomolecular reaction aggregation mechanism.

Tumor-derived apoptotic extracellular vesicle-mediated intercellular communication promotes metastasis and stemness of lung adenocarcinoma

Apoptosis has long been recognized as a significant mechanism for inhibiting tumor formation, and a plethora of stimuli can induce apoptosis during the progression and treatment of tumors. Moreover, tumor-derived apoptotic extracellular vesicles (apoEVs) are inevitably phagocytosed by live tumor cells, promoting tumor heterogeneity. Understanding the mechanism by which apoEVs regulate tumor cells is imperative for enhancing our knowledge of tumor metastasis and recurrence. Herein, we conducted a series of in vivo and in vitro experiments, and we report that tumor-derived apoEVs promoted lung adenocarcinoma (LUAD) metastasis, self-renewal and chemoresistance. Mechanistically, we demonstrated that apoEVs facilitated tumor metastasis and stemness by initiating the epithelial-mesenchymal transition program and upregulating the transcription of the stem cell factor SOX2. In addition, we found that ALDH1A1, which was transported by apoEVs, activated the NF-κB signaling pathway by increasing aldehyde dehydrogenase enzyme activity in recipient tumor cells. Furthermore, targeting apoEVs-ALDH1A1 significantly abrogated these effects. Collectively, our findings elucidate a novel mechanism of apoEV-dependent intercellular communication between apoptotic tumor cells and live tumor cells that promotes the formation of cancer stem cell-like populations, and these findings reveal that apoEVs-ALDH1A1 may be a potential therapeutic target and biomarker for LUAD metastasis and recurrence.

The Alcohol Flush Response

Nearly 540 million people world-wide have facial flushing and an increased heart rate after consuming alcohol.&amp;nbsp; Known as the alcohol flushing response, this reaction to alcohol is a result of a genetic variant in an enzyme aldehyde dehydrogenase 2 (ALDH2), known as ALDH2*2.&amp;nbsp; Mainly carried by those of East Asian descent, the genetic variant is likely the most common genetic variant carried in the world.&amp;nbsp; Carrying this ALDH2*2 genetic variant has important health implications with respect cancer risk which is increased when carriers of the ALDH2*2 genetic variant frequently use of alcohol or tobacco products.&amp;nbsp; &amp;nbsp;This comic explains the alcohol flush response and the health risks associated with alcohol and tobacco use for those who carry an ALDH2*2 variant.&amp;nbsp;

Comparative pharmacogenetic study of disulfiram or cyanamide efficacy for alcohol dependence: the key role of dopamine neurotransmission gene polymorphisms

The actual direction of increasing the efficacy of alcohol dependence (AD) treatment is the search for opportunities for individualization of therapy using pharmacogenetic markers to stratify patients in order to select the most optimal therapeutic tactics.Aims. To test an associations of possible pharmacogenetic markers with indicators of the efficacy of disulfiram and cyanamide to stabilize remission in patients with AD.Materials and methods. A pharmacogenetic study was conducted on the basis of a double-blind, randomized, comparative, placebo-controlled clinical study of the efficacy and tolerability of disulfiram and cyanamide in the treatment of alcohol dependence syndrome. The main outcome: the duration of retention of patients in the treatment program (in remission), and withdrawal from the treatment program for any reason was considered a negative outcome. Secondary outcomes: time to relapse to alcohol use and time to recurrence to AD. 150 patients with AD (ICD-10 criteria) (av. age - 40.65±1.09 y.o., 19.3% females) were randomly assigned to one of three treatment groups (50 subjects in each): Disulfiram, Cyanamid and Placebo. All patients had weekly (12 weeks) visits to research clinic for brief counselling session. The genetic panel of the study consisted of 15 polymorphic loci in 9 genes: dopamine receptors 2 (DRD2) and 4 (DRD4) types, transmembrane dopamine transporter (DAT), enzymes dopamine-beta-hydroxylase (DBH) and catechol-ortho-methyl-transferase, as well as a two polymorphisms in the genes of the endogenous opioid system and the aldehyde dehydrogenase enzyme gene cluster.Results. For disulfiram, the DBH rs1108580 is associated with a longer remission (p=0.053, trend), and DRD4 VNTR 48 bp is associated with a shorter remission (p=0.006). For cyanamide, DAT VNTR 40 bp was associated with shorter remission (p=0.006) and rapid recurrence to AD (p=0.045). DAT rs27072 has an effect simultaneously in two treatment groups, while the direction of the effect is opposite. For cyanamide, the marker is slightly associated with a longer remission (p = 0.082, trend), a longer time to relapse (p = 0.063, trend) and a longer time to recurrence to AD (p = 0.083, trend). For placebo, DAT rs27072, on the contrary, is associated with a shorter time to to recurrence to AD (p = 0.066, trend). For placebo, DRD2 rs1799732 was associated with a shorter remission (p = 0.001), a shorter time to relapse (p = 0.018), and a shorter time to recurrence to AD (p = 0.001).Conclusion. Preliminary pharmacogenetic markers of the efficacy of alcohol dependence treatment have been identified in genes that control dopaminergic neurotransmission. After independent validation, the obtained genetic markers may be used for pharmacogenetic stratification of patients in order to select the optimal treatment options for alcohol dependence.

Aldehyde Dehydrogenase Enzyme in Relation to Cord Blood stem cells Potency

Abstract Introduction/Objective In umbilical cord blood transplantation (UCBT), the number of cluster of differentiation (CD)34+ cells and colony-forming units (CFUs) in the cord blood (CB) graft positively correlate with patient survival. Since aldehyde dehydrogenase (ALDH) activity is high in hematopoietic stem cells, the number of ALDH-bright (ALDHbr) cells was examined in comparison with the number of CD34+ cells and CFUs for the quality assessment of CB units, Aim and objectives; to correlate the aldehyde dehydrogenase (ALDH) enzyme assay with colony-forming unit–granulocyte/macrophage (CFU-GM) assay before cryopreservation of cord blood buffy coats (CBBC), in order to investigate the hypothesis that the ALDH assay might exclude apoptotic cells since it is based on enzyme activity. Methods/Case Report This study was carried out at Benha University Hospital on Fifty (50) samples of Human Umbilical Cord Blood which were processed for mononuclear cells (MNC) separation by density gradient centrifugation method using Ficoll-Paque media that layered on the diluted blood. In parallel, 1 million nucleated cells were sampled and prepared for flow cytometry for analysis of ALDH activity according to the manufacturer’s instructions. Results (if a Case Study enter NA) CD34+ ALDH+ (%) (Of MNC) showed significant positive correlation with ALDH++ (%) (Of CD34+) and numbers of total CFU/40000 cells. Also ALDH++ (%) (Of CD34+) showed significant positive correlation with numbers of total CFU/40000 cells. Conclusion The ALDH assay excludes nonviable and apoptotic cells, and therefore correlates well with CFU enumeration compared to the number of viable CD34+ cells. We propose that the ALDH assay might replace the CFU-GM method in CBU potency measurements.

B-373 The Development of a Logic-Gate Probe to Investigate Hypoxia in Cancer Stem Cells

Abstract Background Cancer stem cells (CSCs) represent only a small fraction of the tumor population, yet they present a profound challenge to cancer treatment. CSCs contribute to tumor complexity via their unique ability to self-renew, develop into multiple lineages, and maintain an unchecked proliferation potential. To identify CSCs, the cytoprotective enzyme aldehyde dehydrogenase 1A1 (ALDH1A1) is a well-annotated biomarker of cancer stemness which is associated with a poor prognosis in patients with gastric and lung cancers when overexpressed. Within CSCs, ALDH1A1 functions to regulate oxidative stress by transforming biological aldehydes into their corresponding non-toxic carboxylic acid counterparts and further is linked to the retinaldehyde signaling pathway. Beyond this enzyme, oxygen availability within the tumor microenvironment (TME) can also influence stemness properties. Specifically, hypoxia, is required to maintain the CSC phenotype by prolonging the undifferentiated state. Methods To study the mechanistic underpinnings of complex relationship in vivo new technologies are needed as current approaches are insufficient. Indeed, probes have been developed to study ALDH1A1 and hypoxia in parallel, however, imaging approaches lack the requisite resolution to ensure they are reporting on the same CSC population. To this end, we have designed a powerful logic-gate probe that links the reporters of ALDH1A1 activity and oxygenation in a unique manner such that different readouts will result (color of light) depending on the TME environment. Results Our lab has previously developed a near-infrared hypoxia-sensing fluorescent probe that is fundamental to our current logic-gate design. This component has been validated in 4T1 murine breast cancer cells, to yield a 1.6-fold increase in ratiometric fluorescence response when incubated under hypoxic conditions as compared to its normoxic controls. Additionally, the ALDH1A1 sensing component has been validated via purified enzyme to yield an increase in bioluminescent signal enabling its use for future in vivo studies. Conclusion This technology has important clinical implications to understand the mechanistic underpinnings between oxygenation and cancer stemness. Further research is being conducted to further test the hypothesis that metformin (anticancer drug) kills cancer by altering oxygen metabolism which in turn depletes the CSC population. Furthermore, this probe has far-reaching implications in monitoring novel therapeutic cancer treatment.

The NADH recycling enzymes TsaC and TsaD regenerate reducing equivalents for Rieske oxygenase chemistry

Many microorganisms use both biological and nonbiological molecules as sources of carbon and energy. This resourcefulness means that some microorganisms have mechanisms to assimilate pollutants found in the environment. One such organism is Comamonas testosteroni, which metabolizes 4-methylbenzenesulfonate and 4-methylbenzoate using the TsaMBCD pathway. TsaM is a Rieske oxygenase, which in concert with the reductase TsaB consumes a molar equivalent of NADH. Following this step, the annotated short-chain dehydrogenase/reductase and aldehyde dehydrogenase enzymes TsaC and TsaD each regenerate a molar equivalent of NADH. This co-occurrence ameliorates the need for stoichiometric addition of reducing equivalents and thus represents an attractive strategy for integration of Rieske oxygenase chemistry into biocatalytic applications. Therefore, in this work, to overcome the lack of information regarding NADH recycling enzymes that function in partnership with Rieske non-heme iron oxygenases (Rieske oxygenases), we solved the X-ray crystal structure of TsaC to a resolution of 2.18 Å. Using this structure, a series of substrate analog and protein variant combination reactions, and differential scanning fluorimetry experiments, we identified active site features involved in binding NAD+ and controlling substrate specificity. Further invitro enzyme cascade experiments demonstrated the efficient TsaC- and TsaD-mediated regeneration of NADH to support Rieske oxygenase chemistry. Finally, through in-depth bioinformatic analyses, we illustrate the widespread co-occurrence of Rieske oxygenases with TsaC-like enzymes. This work thus demonstrates the utility of these NADH recycling enzymes and identifies a library of short-chain dehydrogenase/reductase enzyme prospects that can be used in Rieske oxygenase pathways for in situ regeneration of NADH.

The Overexpression of Peanut (Arachis hypogaea L.) AhALDH2B6 in Soybean Enhances Cold Resistance.

Soybeans are the main source of oils and protein for humans and animals; however, cold stress jeopardizes their growth and limits the soybean planting area. Aldehyde dehydrogenases (ALDH) are conserved enzymes that catalyze aldehyde oxidation for detoxification in response to stress. Additionally, transgenic breeding is an efficient method for producing stress-resistant germplasms. In this study, the peanut ALDH gene AhALDH2B6 was heterologously expressed in soybean, and its function was tested. We performed RNA-seq using transgenic and wild-type soybeans with and without cold treatment to investigate the potential mechanism. Transgenic soybeans developed stronger cold tolerance, with longer roots and taller stems than P3 soybeans. Biochemically, the transgenic soybeans exhibited a decrease in malondialdehyde activity and an increase in peroxidase and catalase content, both of which are indicative of stress alleviation. They also possessed higher levels of ALDH enzyme activity. Two phenylpropanoid-related pathways were specifically enriched in up-regulated differentially expressed genes (DEGs), including the phenylpropanoid metabolic process and phenylpropanoid biosynthetic process. Our findings suggest that AhALDH2B6 specifically up-regulates genes involved in oxidoreductase-related functions such as peroxidase, oxidoreductase, monooxygenase, and antioxidant activity, which is partially consistent with our biochemical data. These findings established the function of AhALDH2B6, especially its role in cold stress processes, and provided a foundation for molecular plant breeding, especially plant-stress-resistance breeding.

Beneficial effects of WON-21 on the symptoms of a hangover and identification of active compounds: experimental studies on antioxidant, anti-inflammation, and alcohol-metabolizing enzymes

Many hangover cure products containing natural ingredients that are also effective against alcohol-related liver damage or improve liver function have recently become available. In addition to curing liver damage, antioxidants, anti-inflammatory agents, and blood ethanol reduction aids are emerging as relief targets that reduce hangover symptoms. We investigated the ameliorating effect of WON-21 herbal medicinal products by studying the mixing ratio of oriental medicine concept with respect to antioxidant potential, anti-inflammation, and aldehyde dehydrogenase (ALDH) and alcohol dehydrogenase (ADH) enzyme activities. WON-21 and its components exerted antioxidant and anti-inflammatory effects. Rutin, taxifolin, and quercetin showed superior antioxidant effects compared to the other components. WON-12 effectively reduced iNOS and COX-2 in LPS-stimulated macrophages. Quercetin and apigenin were 2 compounds effective for the inhibition of iNOS and COX-2. WON-21 and quercetin also significantly increased the activities of ALDH and ADH enzymes in a concentration-dependent manner.

Aldehyde Dehydrogenase and Aldo-Keto Reductase Enzymes: Basic Concepts and Emerging Roles in Diabetic Retinopathy.

Diabetic retinopathy (DR) is a complication of diabetes mellitus that can lead to vision loss and blindness. It is driven by various biochemical processes and molecular mechanisms, including lipid peroxidation and disrupted aldehyde metabolism, which contributes to retinal tissue damage and the progression of the disease. The elimination and processing of aldehydes in the retina rely on the crucial role played by aldehyde dehydrogenase (ALDH) and aldo-keto reductase (AKR) enzymes. This review article investigates the impact of oxidative stress, lipid-derived aldehydes, and advanced lipoxidation end products (ALEs) on the advancement of DR. It also provides an overview of the ALDH and AKR enzymes expressed in the retina, emphasizing their growing importance in DR. Understanding the relationship between aldehyde metabolism and DR could guide innovative therapeutic strategies to protect the retina and preserve vision in diabetic patients. This review, therefore, also explores various approaches, such as gene therapy and pharmacological compounds that have the potential to augment the expression and activity of ALDH and AKR enzymes, underscoring their potential as effective treatment options for DR.

Impaired aldehyde detoxification exacerbates motor deficits in an alpha-synuclein mouse model of Parkinson's disease.

The discovery of biogenic aldehydes in the postmortem parkinsonian brain and the ability of these aldehydes to modify and cross-link proteins has called attention to their possible role in Parkinson's disease. For example, many in vitro studies have found that the aldehyde metabolite of dopamine, 3,4-dihydroxyphenylacetaldehyde (DOPAL), induces the formation of stable, neurotoxic alpha-synuclein oligomers. To study this in vivo, mice deficient in the two aldehyde dehydrogenase enzymes (Aldh1a1 and Aldh2, DKO) primarily responsible for detoxification of DOPAL in the nigrostriatal pathway were crossed with mice that overexpress human wild-type alpha-synuclein. DKO overexpressing human wild-type alpha-synuclein (DKO/ASO) offspring were evaluated for impairment on motor tasks associated with Parkinsonism. DKO/ASO mice developed severe motor deficits greater than that of mice overexpressing human wild-type alpha-synuclein alone. These results provide evidence to support the idea that biogenic aldehydes such as DOPAL interact with human wild-type alpha-synuclein, directly or indirectly, in vivo to exacerbate locomotor deficits in Parkinson's disease.

792-P: GLP-1 RA Therapy Increases Circulating Vascular Regenerative Cell Content and Decreases Inflammatory Burden in People with T2D

CV outcome trials have established that long-term use of GLP-1 receptor agonists (GLP-1RAs) yields important CV benefits in people with T2D. Similar to SGLT2i, GLP-1RAs are recommended for people with T2D who have established CVD and heart failure regardless of their A1C. In a randomized trial of people with T2D and coronary artery disease, use of the SGLT2i empagliflozin for 6 months increased the frequency of vascular regenerative (VR) cells in the circulation. To determine if GLP-1RA therapy has a similar impact on the same VR cell populations, we retrospectively analyzed data from an ongoing research program with adults &amp;gt;40 years of age with T2D. Peripheral blood mononuclear cells were isolated and profiled with an established flow cytometry assay that was founded on the activity of the anti-oxidative enzyme aldehyde dehydrogenase (ALDH) that is highly expressed in progenitor (ALDHhi) versus mature (ALDHlow) cells. At baseline, 17 participants were on a GLP-1RA (9 of whom were also on an SGLT2i), 33 were on an SGLT2i but not a GLP-1RA, and 28 were on neither drug class. Mean age, weight, BMI, A1C, and duration of T2D was balanced across the groups. The frequency of ALDHhiSSClow cells (primitive hematopoietic and endothelial progenitor cells that coordinate angiogenesis) was higher in participants who were on a GLP-1RA (0.064%) or an SGLT2i (0.048%) relative to those not on either drug class (0.037%; P&amp;lt;0.05 for both). The frequencies of VR ALDHhiSSCmid monocytes in the three groups were comparable. The frequency of pro-inflammatory ALDHhiSSChi granulocyte precursor cells in participants on a GLP-1RA (2.9%) was lower than that in individuals on an SGLT2i (4.3%; P=0.05) or not on either drug class (5.2%; P&amp;lt;0.01). GLP-1RA therapy in people with T2D was associated with greater VR cell content and lower inflammatory burden. Augmented vessel repair mediated by higher VR cell content may account in part for the CV benefits observed with GLP-1RA in the setting of T2D. Disclosure A.Krishnaraj: None. B.Park: None. E.Bakbak: None. Y.Pan: None. A.Quan: None. H.Teoh: None. S.Verma: Advisory Panel; Amgen Canada, AstraZeneca, Bayer Inc., Boehringer Ingelheim and Eli Lilly Alliance, HLS Therapeutics Inc., Janssen Pharmaceuticals, Inc., Novartis Canada, Novartis, Novo Nordisk, Novo Nordisk Canada Inc., Consultant; AstraZeneca, Other Relationship; Amarin Corporation, AstraZeneca, Bayer Inc., Boehringer Ingelheim and Eli Lilly Alliance, Boehringer Ingelheim International GmbH, Canadian Medical and Surgical Knowledge Translation Research Group, EOCI Pharmacomm, HLS Therapeutics Inc., Janssen Pharmaceuticals, Inc., Novartis Canada, Novo Nordisk, Novo Nordisk Canada Inc., Pfizer Inc., PhaseBio Pharmaceuticals, Inc., S &amp; L Solutions Event Management Inc, Sanofi, Sun Pharmaceutical Industries Ltd., Toronto Knowledge Translation Working Group, Research Support; Amarin Corporation, Amgen Canada, AstraZeneca, Bayer Inc., Boehringer Ingelheim International GmbH, HLS Therapeutics Inc., Novartis, Novo Nordisk, Pfizer Inc., PhaseBio Pharmaceuticals, Inc. D.A.Hess: None.

Targeting aldehyde dehydrogenase enzymes in combination with chemotherapy and immunotherapy: An approach to tackle resistance in cancer cells.

Modern cancer chemotherapy originated in the 1940s, and since then, many chemotherapeutic agents have been developed. However, most of these agents show limited response in patients due to innate and acquired resistance to therapy, which leads to the development of multi-drug resistance to different treatment modalities, leading to cancer recurrence and, eventually, patient death. One of the crucial players in inducing chemotherapy resistance is the aldehyde dehydrogenase (ALDH) enzyme. ALDH is overexpressed in chemotherapy-resistant cancer cells, which detoxifies the generated toxic aldehydes from chemotherapy, preventing the formation of reactive oxygen species and, thus, inhibiting the induction of oxidative stress and the stimulation of DNA damage and cell death. This review discusses the mechanisms of chemotherapy resistance in cancer cells promoted by ALDH. In addition, we provide detailed insight into the role of ALDH in cancer stemness, metastasis, metabolism, and cell death. Several studies investigated targeting ALDH in combination with other treatments as a potential therapeutic regimen to overcome resistance. We also highlight novel approaches in ALDH inhibition, including the potential synergistic employment of ALDH inhibitors in combination with chemotherapy or immunotherapy against different cancers, including head and neck, colorectal, breast, lung, and liver.

Trans-cinnamaldehyde-related overproduction of benzoic acid and oxidative stress on Arabidopsis thaliana.

Trans-cinnamaldehyde is a specialised metabolite that naturally occurs in plants of the Lauraceae family. This study focused on the phytotoxic effects of this compound on the morphology and metabolism of Arabidopsis thaliana seedlings. To evaluate the phytotoxicity of trans-cinnamaldehyde, a dose-response curve was first performed for the root growth process in order to calculate the reference inhibitory concentrations IC50 and IC80 (trans-cinnamaldehyde concentrations inducing a 50% and 80% inhibition, respectively). Subsequently, the structure and ultrastructure of the roots treated with the compound were analysed by light and electron microscopy. Based on these results, the following assays were carried out to in depth study the possible mode of action of the compound: antiauxinic PCIB reversion bioassay, determination of mitochondrial membrane potential, ROS detection, lipid peroxidation content, hormone quantification, in silico studies and gene expression of ALDH enzymes. Trans-cinnamaldehyde IC50 and IC80 values were as low as 46 and 87 μM, reducing the root growth and inducing the occurrence of adventitious roots. At the ultrastructural level, the compound caused alterations to the mitochondria, which were confirmed by detection of the mitochondrial membrane potential. The morphology observed after the treatment (i.e., appearance of adventitious roots) suggested a possible hormonal mismatch at the auxin level, which was confirmed after PCIB bioassay and hormone quantification by GC-MS. The addition of the compound caused an increase in benzoic, salicylic and indoleacetic acid content, which was related to the increased gene expression of the aldehyde dehydrogenase enzymes that can drive the conversion of trans-cinnamaldehyde to cinnamic acid. Also, an increase of ROS was also observed in treated roots. The enzyme-compound interaction was shown to be stable over time by docking and molecular dynamics assays. The aldehyde dehydrogenases could drive the conversion of trans-cinnamaldehyde to cinnamic acid, increasing the levels of benzoic, salicylic and indoleacetic acids and causing the oxidative stress symptoms observed in the treated seedlings. This would result into growth and development inhibition of the trans-cinnamaldehyde-treated seedlings and ultimately in their programmed-cell-death.

Effect of ZEB1 Associated with microRNAs on Tumor Stem Cells in Head and Neck Cancer

Cancer biologists have focused on studying cancer stem cells (CSCs) because of their ability to self-renew and recapitulate tumor heterogeneity, which increases their resistance to chemotherapy and is associated with cancer relapse. Here, we used two approaches to isolate CSCs: the first involved the metabolic enzyme aldehyde dehydrogenase ALDH, and the second involved the three cell surface markers CD44, CD117, and CD133. ALDH cells showed a higher zinc finger E-box binding homeobox 1 (ZEB1) microRNA (miRNA) expression than CD44/CD117/133 triple-positive cells, which overexpressed miRNA 200c-3p: a well-known microRNA ZEB1 inhibitor. We found that ZEB1 inhibition was driven by miR-101-3p, miR-139-5p, miR-144-3p, miR-199b-5p, and miR-200c-3p and that the FaDu Cell Line inhibition occurred at the mRNA level, whereas HN13 did not affect mRNA expression but decreased protein levels. Furthermore, we demonstrated the ability of the ZEB1 inhibitor miRNAs to modulate CSC-related genes, such as TrkB, ALDH, NANOG, and HIF1A, using transfection technology. We showed that ALDH was upregulated upon ZEB1-suppressed miRNA transfection (Mann-Whitney ** p101 = 0.009, t-test ** p139 = 0.009, t-test ** p144 = 0.002, and t-test *** p199 = 0.0006). Overall, our study enabled an improved understanding of the role of ZEB1-suppressed miRNAs in CSC biology.

In Vitro Evaluation of ALDH1A3-Affinic Compounds on Breast and Prostate Cancer Cell Lines as Single Treatments and in Combination with Doxorubicin.

Aldehyde dehydrogenase (ALDH) enzymes are involved in the growth and development of several tissues, including cancer cells. It has been reported that targeting the ALDH family, including the ALDH1A subfamily, enhances cancer treatment outcomes. Therefore, we aimed to investigate the cytotoxicity of ALDH1A3-affinic compounds that have been recently discovered by our group, on breast (MCF7 and MDA-MB-231) and prostate (PC-3) cancer cell lines. These compounds were investigated on the selected cell lines as single treatments and in combination with doxorubicin (DOX). Results showed that the combination treatment experiments of the selective ALDH1A3 inhibitors (compounds 15 and 16) at variable concentrations with DOX resulted in significant increases in the cytotoxic effect on the MCF7 cell line for compound 15, and to a lesser extent for compound 16 on the PC-3 cell line, compared to DOX alone. The activity of compounds 15 and 16 as single treatments on all cell lines was found to be non-cytotoxic. Therefore, our findings showed that the investigated compounds have a promising potential to target cancer cells, possibly via an ALDH-related pathway, and sensitize them to DOX treatment.

The “Asian flush syndrome”: ALDH2 Deficiency and Long-term Health Consequences

Harmful use of alcohol leads to roughly 3 million deaths worldwide every year, and is linked to the development of roughly 230 different types of disease (World Health Organization, 2016). As alcohol has the ability to diffuse through cell membranes, its toxicity can heavily impact almost all organs within the human body. A large proportion of the East Asian population experiences the “Asian flush syndrome” post-drinking, which induces characteristic facial-flushing symptoms caused by an aldehyde dehydrogenase (ALDH2) enzyme deficiency due to an ALDH2 gene mutation. In the past, investigations on links between ALDH2 deficiencies and long-term health consequences have been conducted with conclusive evidence that confirm that “Asian flushers'' have a predisposed risk for various diseases, including cancer and cardiovascular disease. This literature review systematically compiles research that explains the mechanisms behind ALDH2 deficient communities and increased health risks to esophageal cancer, cardiovascular disease, and Alzhiemer’s disease. Furthermore, it shows that risk levels for disease are compounded when alcohol intake is increased. The preventative measures and social factors are also considered, including recommendations for further interventions to increase awareness and decrease alcohol intake in affected individuals.