Aldehyde Dehydrogenase Activity Research Articles

CHK1 inhibitor induced PARylation by targeting PARG causes excessive replication and metabolic stress and overcomes chemoresistance in ovarian cancer

Chemoresistance contributes to the majority of deaths in women with ovarian cancer (OC). Altered DNA repair and metabolic signaling is implicated in mediating therapeutic resistance. DNA damage checkpoint kinase 1 (CHK1) integrates cell cycle and DNA repair in replicating cells, and its inhibition causes replication stress, repair deficiency and cell cycle dysregulation. We observed elevated Poly-ADP-ribosylation (PAR) of proteins (PARylation) and subsequent decrease in cellular NAD+ levels in OC cells treated with the CHK1 inhibitor prexasertib, indicating activation of NAD+ dependent DNA repair enzymes poly-ADP-ribose polymerases (PARP1/2). While multiple PARP inhibitors are in clinical use in treating OC, tumor resistance to these drugs is highly imminent. We reasoned that inhibition of dePARylation by targeting Poly (ADP-ribose) glycohydrolase (PARG) would disrupt metabolic and DNA repair crosstalk to overcome chemoresistance. Although PARG inhibition (PARGi) trapped PARylation of the proteins and activated CHK1, it did not cause any significant OC cell death. However, OC cells deficient in CHK1 were hypersensitive to PARGi, suggesting a role for metabolic and DNA repair crosstalk in protection of OC cells. Correspondingly, OC cells treated with a combination of CHK1 and PARG inhibitors exhibited excessive replication stress-mediated DNA lesions, cell cycle dysregulation, and mitotic catastrophe compared to individual drugs. Interestingly, increased PARylation observed in combination treatment resulted in depletion of NAD+ levels. These decreased NAD+ levels were also paralleled with reduced aldehyde dehydrogenase (ALDH) activity, which requires NAD+ to maintain cancer stem cells. Furthermore, prexasertib and PARGi combinations exhibited synergistic cell death in OC cells, including an isogenic chemoresistant cell line and 3D organoid models of primary patient-derived OC cell lines. Collectively, our data highlight a novel crosstalk between metabolism and DNA repair involving replication stress and NAD+-dependent PARylation, and suggest a novel combination therapy of CHK1 and PARG inhibitors to overcome chemoresistance in OC.

Effects of Silybum marianum, Pueraria lobate, combined with Salvia miltiorrhiza tablets on non-alcoholic fatty liver disease in adults: A triple-blind, randomized, placebo-controlled clinical trial

Background & aimsSeveral medicinal plant extracts have demonstrated hepatoprotective effects. However, data are scarce regarding their combined effects on non-alcoholic fatty liver disease (NAFLD). This study aimed to investigate the effects of tablets containing Silybum marianum, Pueraria lobata, and Salvia miltiorrhiza (SPS) on NAFLD progression in Chinese adults. MethodsIn this randomized, triple-blind, placebo-controlled clinical trial, 121 NAFLD patients (61 female and 60 male), diagnosed via magnetic resonance imaging (MRI) and aged 18-65 years, were enrolled. Participants were randomly allocated to receive SPS tablets (n=61; three tablets per dose, twice daily) or placebo (n=60) for 24 weeks. Each SPS tablet contained approximately 23.0 mg of silybin, 11.4 mg of puerarin, and 10.9 mg of salvianolic acid. There were no differences in appearance, taste and odour between the SPS tablets and placebo manufactured by BY-HEALTH Co Ltd (Guangzhou, China). The primary endpoints were changes in the liver fat content (LFC) and steatosis grade from baseline to 24 weeks. Secondary outcomes included changes in biomarkers/scores of liver fibrosis and steatosis, oxidative stress, inflammatory cytokines, alcohol metabolism, and glucose metabolism. ResultsA total of 112 participants completed the research. The intention-to-treat results showed a trend toward reduction in both absolute LFC (-0.52%) and percentage of LFC (-4.57%) in the SPS group compared to the placebo group after 24 weeks, but these changes didn’t reach statistical significance (p > 0.05). The SPS intervention (vs. placebo) significantly decreased hypersensitive C-reactive protein level (-6.76%) and increased aldehyde dehydrogenase activity (+18.1%) at 24 weeks post-intervention (all p < 0.05). Per-protocol analysis further supported these effects. This trial is registered at Clinical Trials.gov (NCT05076058). ConclusionSPS supplementation may have potential benefits in improving NAFLD, but further larger-scale trials are necessary to confirm these findings.

Pharmaceutical composition of 1,2,4-trioxolanes with betulin in fish oil. Effect on oxidative and energy metabolism in the treatment of burns in rats

Background. Ozonation products of unsaturated fatty acids in fats and oils – 1,2,4-trioxolanes – which contribute to the normalization of oxidative and energy metabolism in various diseases, may be a promising substance for the creation of new combined anti-burn drugs.The aim. To study the effect of 1,2,4-trioxolanes in a pharmaceutical composition with betulin, which exhibits wound-healing properties, on indicators of oxidative stress and on energy metabolism in the treatment of burns in an experiment onrats. Methods. The experiments were carried out on 50 male Wistar rats with seconddegree skin burns. We assessed the activity of glutathione reductase, glucose-6-phosphate dehydrogenase, lactate dehydrogenase, aldehyde dehydrogenase, superoxide dismutase and catalase, as well as the level of lipid peroxidation indicators.Results. The properties of 1,2,4-trioxolanes were studied and a pharmaceutical composition of 1,2,4-trioxolanes with betulin from birch bark in fish oil was developed. The effect of this composition on oxidative and energy metabolism in rats during the treatment of burns was studied. The activation of NADP/H and NAD/H dependent enzymes (glutathione reductase, glucose-6-phosphate dehydrogenase, lactate dehydrogenase, aldehyde dehydrogenase), as well as superoxide dismutase and catalase, and the normalization of lipid peroxidation parameters under the influence of the studied composition in the treatment of burns were revealed. The effect of the composition on the energy metabolism of erythrocytes was noted, which was assessed by changes in the ratio of lactate dehydrogenase activity in the reverse and direct reactions. Morphohistological studies showed that using the composition under normal conditions and in case of a burn had no effect on the structure of the stomach wall, and also improved the condition of the burn wound on the day 10 compared to the wound condition in animals without treatment.Conclusion. The proposed composition of 1,2,4-trioxolanes and betulin in fish oil, which allows normalizing oxidative and energy metabolism and improving the condition of a burn wound without toxic effects on the stomach wall, can be used as an element of additional therapy in the treatment of burns.

Influence of Aldehyde Dehydrogenase Inhibition on Stemness of Endometrial Cancer Stem Cells.

Endometrial cancer is one of the most common gynaecological malignancies. Although often diagnosed at an early stage, there is a subset of patients with recurrent and metastatic disease for whom current treatments are not effective. Cancer stem cells (CSCs) play a pivotal role in triggering tumorigenesis, disease progression, recurrence, and metastasis, as high aldehyde dehydrogenase (ALDH) activity is associated with invasiveness and chemotherapy resistance. Therefore, this study aimed to evaluate the effects of ALDH inhibition in endometrial CSCs. ECC-1 and RL95-2 cells were submitted to a sphere-forming protocol to obtain endometrial CSCs. ALDH inhibition was evaluated through ALDH activity and expression, sphere-forming capacity, self-renewal, projection area, and CD133, CD44, CD24, and P53 expression. A mass spectrometry-based proteomic study was performed to determine the proteomic profile of endometrial cancer cells upon N,N-diethylaminobenzaldehyde (DEAB). DEAB reduced ALDH activity and expression, along with a significant decrease in sphere-forming capacity and projection area, with increased CD133 expression. Additionally, DEAB modulated P53 expression. Endometrial cancer cells display a distinct proteomic profile upon DEAB, sharing 75 up-regulated and 30 down-regulated proteins. In conclusion, DEAB inhibits ALDH activity and expression, influencing endometrial CSC phenotype. Furthermore, ALDH18A1, SdhA, and UBAP2L should be explored as novel molecular targets for endometrial cancer.

Gastric adenocarcinoma predictive long intergenic noncoding RNA (GAPLINC) promotes oral cancer stemness by acting as a molecular sponge of miR331-3p

Background/purposeAccumulating evidence has suggested that treatment failure of cancer therapy can be attributed to cancer stem cells (CSCs). Among numerous regulators of cancer stemness, non-coding RNAs (ncRNAs) have gained significant attention recently. In this study, we examined the role of gastric adenocarcinoma predictive long intergenic noncoding RNA (GAPLINC) in oral CSCs (OCSCs). Materials and methodsRNA Sequencing and quantitative real-time polymerase chain reaction (qRT-PCR) were used to determine the expression of GAPLINC. Flow cytometry and sphere-forming assay were exploited to isolate OCSCs. Measurement of aldehyde dehydrogenase 1 (ALDH1) activity, CD44 expressing cells, and various phenotypic assays, such as self-renewal, migration, invasion, and colony-forming abilities, were conducted in CSCs of two types of oral cancer cells (SAS and GNM) following the knockdown of GAPLINC. A luciferase reporter was also carried out to validate the direct interaction between GAPLINC and microRNA (miR)-331-3p. ResultsOur results showed that GAPLINC was overexpressed in OCSCs from patient-derived and oral cancer cell lines. We demonstrated that silencing of GAPLINC in OCSCs downregulated various CSC hallmarks, such as ALDH1 activity, percentage of CD44-expressing cells, self-renewal capacity, and colony-forming ability. Moreover, our results revealed that the effect of GAPLINC on cancer stemness was mediated by direct repression of miR-331-3p. ConclusionThese data have potential clinical implications in that we unraveled the aberrant upregulation of GAPLINC and demonstrated that suppression of GAPLINC may reduce cancer stemness via sequestering miR-331-3p.

Mitochondrial ALDH2 improves ß-cell survival and function against doxorubicin-induced apoptosis by targeting CK2 signaling.

The aim of this study was to better understand how the chemotherapy drug doxorubicin contributes to the development of β-cell dysfunction and to explore its relationship with mitochondrial aldehyde dehydrogenase-2 (ALDH2). In order to investigate this hypothesis, doxorubicin was administered to INS-1 cells, a rat insulinoma cell line, either with or without several target protein activators and inhibitors. ALDH2 activity was detected with a commercial kit and protein levels were determined with western blot. Mitochondrial ROS, membrane potential, and lipid ROS were determined by commercial fluorescent probes. The cell viability was measured by CCK-assay. Exposure of INS-1 cells to doxorubicin decreased active insulin signaling resulting in elevated ALDH2 degradation, compared with control cells by the induction of acid sphingomyelinase mediated ceramide induction. Further, ceramide induction potentiated doxorubicin induced mitochondrial dysfunction. Treatment with the ALDH2 agonist, ALDA1, blocked doxorubicin-induced acid sphingomyelinase activation which significantly blocked ceramide induction and mitochondrial dysfunction mediated cell death. Treatment with the ALDH2 agonist, ALDA1, stimulated casein kinase-2 (CK2) mediated insulin signaling activation. CK2 silencing neutralized the function of ALDH2 in the doxorubicin treated INS-1 cells. Mitochondrial ALDH2 activation could inhibit the progression of doxorubicin induced pancreatic β-cell dysfunction by inhibiting the acid sphingomyelinase induction of ceramide, by regulating the activation of CK2 signaling. Our research lays the foundation of ALDH2 activation as a therapeutic target for the precise treatment of chemotherapy drug induced β-cell dysfunction.

The importance of disturbances in alcohol dehydrogenase and aldehyde dehydrogenase activities in prostate cancer cells

The importance of disturbances in alcohol dehydrogenase and aldehyde dehydrogenase activities in prostate cancer cells

Enhancing hydrogen production from oily sludge: A novel approach using household waste digestate to overcome mono-ethylene glycol inhibition

Herein, a novel approach for H2 production is presented by exploiting the synergistic potential of digestate derived from household waste (D) in the co-digestion process with oily sludge (OS), rich in mono-ethylene glycol (MEG). Our approach significantly mitigates the environmental impact of OS, a hazardous byproduct of petroleum industry, while addressing the challenge of MEG inhibition in H2 production, along with biochar recovery.Remarkably, anaerobic co-digestion of OS:D (60:40) yielded a remarkable 23.1-fold increase in hydrogen potential (436.3 ± 34.8 mL) compared to 18.7 ± 0.9 mL in OS:D (100:0). This enhanced hydrogen productivity was complemented by a notable MEG biodegradation efficiency of 86.2 ± 7.8%. Furthermore, the microbial community played a crucial role in metabolizing MEG into ethanol, acetaldehyde, and acetate through the enzymatic activities of aldehyde dehydrogenase and alcohol dehydrogenase. Dominant strains such as Clostridium (3.9%), Acinetobacter (12.7%), and Bacillus (2.1%) were identified for MEG degradation, contributing significantly to high H2-productivity.

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.

Icosapent ethyl modulates circulating vascular regenerative cell content: The IPE-PREVENTION CardioLink-14 trial

REDUCE-IT (Reduction of Cardiovascular Events with Icosapent Ethyl-Intervention Trial) showed that icosapent ethyl (IPE) reduced major adverse cardiovascular events by 25%. Since the underlying mechanisms for these benefits are not fully understood, the IPE-PREVENTION CardioLink-14 trial (ClinicalTrials.gov: NCT04562467) sought to determine if IPE regulates vascular regenerative (VR) cell content in people with mild to moderate hypertriglyceridemia. Seventy statin-treated individuals with triglycerides ≥1.50 and <5.6mmol/L and either atherosclerotic cardiovascular disease or type 2 diabetes with additional cardiovascular risk factors were randomized to IPE (4 g/day) or usual care. VR cells with high aldehyde dehydrogenase activity (ALDHhi) were isolated from blood collected at the baseline and 3-month visits and characterized with lineage-specific cell surface markers. The primary endpoint was the change in frequency of pro-vascular ALDHhiside scatter (SSC)lowCD133+ progenitor cells. Change in frequencies of ALDHhiSSCmid monocyte and ALDHhiSSChi granulocyte precursor subsets, reactive oxygen species production, serum biomarkers, and omega-3 levels were also evaluated. Baseline characteristics, cardiovascular risk factors, and medicationswere balanced between the groups. Compared to usual care, IPE increased the mean frequency of ALDHhiSSClowCD133+ cells (-1.00%± 2.45% vs.+7.79%± 1.70%; p= 0.02), despite decreasing overall ALDHhiSSClow cell frequency. IPE assignment also reduced oxidative stress in ALDHhiSSClow progenitors and increased ALDHhiSSChi granulocyte precursor cell content. IPE-PREVENTION CardioLink-14 provides the first translational evidence that IPE can modulate VR cell content and suggests a novel mechanism that may underlie the cardioprotective effects observed with IPE in REDUCE-IT. HLS Therapeutics provided the IPE in kind and had no role in the study design, conduct, analyses, or interpretation.

Abstract 7227: Isatin analogs potentiate the cytotoxicity of venetoclax in acute myeloid leukemia cells

Abstract Acute Myeloid Leukemia (AML) is a rare but common hematological malignancy in children and adults. AML is a highly heterogeneous disease caused by the acquisition of several mutations affecting multiple cellular processes, thus requiring concomitant targeting of key survival nodes to treat effectively. As current first-line therapies for AML suffer with poor outcomes, drug resistance, and high relapse rates, there is an immediate need for new combinatorial therapies that are both safe and effective. Venetoclax (VEN), a selective inhibitor of antiapoptotic protein B-cell lymphoma-2 (BCL2), has been FDA-approved for treating adult AML and displayed potential in pediatric leukemia treatment. However, the activation of an antiapoptotic BCL2 family member, Myeloid Cell Leukemia 1 (MCL1), is often a primary mechanism of resistance to VEN therapy. Our group has developed Isatin analogs (ISA) that exhibited diverse biological activities, including anti-cancer activities alone or in combination with standard agents. ISA demonstrated anti-leukemic activity by targeting leukemic stem cells (LSCs) with high aldehyde dehydrogenase (ALDH) activity. In this study, we demonstrate ISA induces apoptosis by downregulating antiapoptotic MCL1 levels in pediatric and adult AML cell lines. Based on the inhibitory effects of Isatin analogs on key signaling pathways (PI3K/AKT, STAT3) and MCL1, we combined ISA with a BCL2 inhibitor, VEN, for effective AML treatment. The combination of ISA with VEN exhibited synergetic cytotoxicity in naïve (MOLM-13, MV4-11) and VEN-resistant (HL-60, OCI-AML3, U937, and KG-1) human AML cell lines by bliss analysis. ISA also showed significant synergetic cytotoxicity in combination with ABT-737, a BH3 mimetic inhibitor of Bcl-xL, Bcl-2, and Bcl-w. Combinatorial treatment of AML cell lines with sub-lethal doses of ISA and VEN showed a significant increase in cellular apoptosis as indicated by the levels of annexin V measured by flow cytometry. Immunoblotting analysis after co-treatment with ISA and VEN showed downregulation of MCL1 levels along with alteration of other key apoptosis regulators in both VEN-sensitive (MV4-11) and inherently VEN-resistant (U937) AML cell lines. Current and future studies will primarily focus on further exploiting the molecular mechanism of action for the combinatorial approach. Furthermore, our aim will be to demonstrate activity in primary patient cells along with preclinical efficacy in AML animal models. To summarize, in vitro findings showed synergetic cooperation between ISA and VEN in combination for effective induction of apoptosis and anti-leukemic activity in AML cells that are sensitive and resistant to VEN. Citation Format: Upendarrao Golla, Satyam Patel, Jeremy Hengst, Charyguly Annageldiyev, Joseph Schramm, Shantu Amin, Dhimant Desai, David Claxton, Sinisa Dovat, Arati Sharma. Isatin analogs potentiate the cytotoxicity of venetoclax in acute myeloid leukemia cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7227.

Aldehyde Dehydrogenase 2 (ALDH2): A novel sorafenib target in hepatocellular carcinoma unraveled by the proteome-wide cellular thermal shift assay

Sorafenib is a multikinase inhibitor indicated for first-line treatment of unresectable hepatocellular carcinoma. Despite its widespread use in the clinic, the existing knowledge of sorafenib mode-of-action remains incomplete. To build upon the current understanding, we used the Cellular Thermal Shift Assay (CETSA) coupled to Mass Spectrometry (CETSA-MS) to monitor compound binding to its target proteins in the cellular context on a proteome-wide scale. Among the potential sorafenib targets, we identified aldehyde dehydrogenase 2 (ALDH2), an enzyme that plays a major role in alcohol metabolism. We validated the interaction of sorafenib with ALDH2 by orthogonal methods using pure recombinant protein, proving that this interaction is not mediated by other cellular components. Moreover, we showed that sorafenib inhibits ALDH2 activity, supporting a functional role for this interaction. Finally, we were able to demonstrate that both ALDH2 protein expression and activity were reduced in sorafenib-resistant cells compared to the parental cell line. Overall, our study allowed the identification of ALDH2 as a novel sorafenib target and sheds light on its potential role in both hepatocellular carcinoma and sorafenib resistance condition.

Renal toxicity of ifosfamide in children with cancer: an exploratory study integrating aldehyde dehydrogenase enzymatic activity data and a wide-array urinary metabolomics approach

BackgroundIfosfamide is a major anti-cancer drug in children with well-known renal toxicity. Understanding the mechanisms underlying this toxicity could help identify children at increased risk of toxicity.MethodsThe IFOS01 study included children undergoing ifosfamide-based chemotherapy for Ewing sarcoma or rhabdomyosarcoma. A fully evaluation of renal function was performed during and after chemotherapy. Proton nuclear magnetic resonance (NMR) and conventional biochemistry were used to detect early signs of ifosfamide-induced tubulopathy. The enzymatic activity of aldehyde dehydrogenase (ALDH) was measured in the peripheral blood lymphocytes as a marker of ifosfamide-derived chloroacetaldehyde detoxification capacity. Plasma and urine concentrations of ifosfamide and dechloroethylated metabolites were quantified.ResultsThe 15 participants received a median total ifosfamide dose of 59 g/m2 (range: 24–102), given over a median of 7 cycles (range: 4–14). All children had acute proximal tubular toxicity during chemotherapy that was reversible post-cycle, seen with both conventional assays and NMR. After a median follow-up of 31 months, 8/13 children presented overall chronic toxicity among which 7 had decreased glomerular filtration rate. ALDH enzymatic activity showed high inter- and intra-individual variations across cycles, though overall activity looked lower in children who subsequently developed chronic nephrotoxicity. Concentrations of ifosfamide and metabolites were similar in all children.ConclusionsAcute renal toxicity was frequent during chemotherapy and did not allow identification of children at risk for long-term toxicity. A role of ALDH in late renal dysfunction is possible so further exploration of its enzymatic activity and polymorphism should be encouraged to improve the understanding of ifosfamide-induced nephrotoxicity.

Abstract A110: Targeting methionine metabolism inhibits ovarian cancer stem cells

Abstract Ovarian cancer (OC) is the leading cause of gynecologic cancer death. Platinum (Pt)- based chemotherapy can reprogram cancer cells to ovarian cancer stem cells (OCSCs) and contribute to disease recurrence. In the current study, we demonstrated that platinum drugs can enrich for OCSCs. In high grade serous ovarian cancer (HGSOC) cell lines, cisplatin treatment (IC50 for 16hrs) increased the percentage of cells with high aldehyde dehydrogenase (ALDH+) activity, a known OCSCs marker, and altered methionine (Met) metabolism. Extracellular Met uptake is converted to S-adenosyl-methionine (SAM) by methionine adenosyltransferase 2A (MAT2A), the rate-limiting enzyme of Met utilization. Short-term cisplatin treatment decreased SAM level and increased expression of MAT2A. It has been reported that CSCs have a high-flux metabolic state and are dependent on Met metabolism. We observed higher MAT2A expression in ALDH+ cells compared to the whole cell population, and Met depletion blocked the cisplatin-induced increase in %ALDH+ cells and spheroid formation ability. Furthermore, both MAT2A siRNA knockdown and the MAT2A inhibitor FIDAS-5 prevented cisplatin-induced increase in %ALDH+ cells, suggesting that blocking Met metabolism phenotypically inhibited the platinum enrichment of OCSCs. MAT2A inhibition also downregulated Cyclin E and arrested HGSOC cells in G1/S phase, indicating that a lower level of Met utilization re-established G1/S checkpoint in p53-mutant OC. As SAM is the universal methyl-group donor, it was of interest to examine whether the observed cisplatin-induced alterations in SAM level resulted in changes in DNA methylation. Methylation specific-PCR analysis demonstrated that siMAT2A or FIDAS-5 treatment of HGSOC cells inhibited cisplatin-induced hypermethylation of CpG islands of BRCA1 and ALDH1L1, a folate metabolic enzyme of which promoter hypermethylation is associated to tumor progression. Collectively, these results demonstrated a crucial role of Met metabolism in cisplatin-induced OCSCs enrichment. MAT2A has been recognized as a therapeutic target for the treatment of solid tumors and Met inhibition by targeting MAT2A could represent a therapeutic approach for inhibiting CSC in ovarian cancer. Citation Format: Shu Zhang, Tara X. Metcalfe, Christiane A. Hassel, Heather M. O'Hagan, Kenneth P. Nephew. Targeting methionine metabolism inhibits ovarian cancer stem cells [abstract]. In: Proceedings of the AACR Special Conference on Ovarian Cancer; 2023 Oct 5-7; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_2):Abstract nr A110.

Exogenous betaine enhances salt tolerance of Glycyrrhiza uralensis through multiple pathways

BackgroundGlycyrrhiza uralensis Fisch., a valuable medicinal plant, shows contrasting salt tolerance between seedlings and perennial individuals, and salt tolerance at seedling stage is very weak. Understanding this difference is crucial for optimizing cultivation practices and maximizing the plant’s economic potential. Salt stress resistance at the seedling stage is the key to the cultivation of the plant using salinized land. This study investigated the physiological mechanism of the application of glycine betaine (0, 10, 20, 40, 80 mM) to seedling stages of G. uralensis under salt stress (160 mM NaCl).ResultsG. uralensis seedlings’ growth was severely inhibited under NaCl stress conditions, but the addition of GB effectively mitigated its effects, with 20 mM GB had showing most significant alleviating effect. The application of 20 mM GB under NaCl stress conditions significantly increased total root length (80.38%), total root surface area (93.28%), and total root volume (175.61%), and significantly increased the GB content in its roots, stems, and leaves by 36.88%, 107.05%, and 21.63%, respectively. The activity of betaine aldehyde dehydrogenase 2 (BADH2) was increased by 74.10%, 249.38%, and 150.60%, respectively. The 20 mM GB-addition treatment significantly increased content of osmoregulatory substances (the contents of soluble protein, soluble sugar and proline increased by 7.05%, 70.52% and 661.06% in roots, and also increased by 30.74%, 47.11% and 26.88% in leaves, respectively.). Furthermore, it markedly enhanced the activity of antioxidant enzymes and the content of antioxidants (SOD, CAT, POD, APX and activities and ASA contents were elevated by 59.55%, 413.07%, 225.91%, 300.00% and 73.33% in the root, and increased by 877.51%, 359.89%, 199.15%, 144.35%, and 108.11% in leaves, respectively.), and obviously promoted salt secretion capacity of the leaves, which especially promoted the secretion of Na+ (1.37 times).ConclusionsIn summary, the exogenous addition of GB significantly enhances the salt tolerance of G. uralensis seedlings, promoting osmoregulatory substances, antioxidant enzyme activities, excess salt discharge especially the significant promotion of the secretion of Na+Future studies should aim to elucidate the molecular mechanisms that operate when GB regulates saline stress tolerance.

Comprehensive analysis of the aldehyde dehydrogenase gene family in Phaseolus vulgaris L. and their response to saline-alkali stress.

Aldehyde dehydrogenase (ALDH) scavenges toxic aldehyde molecules by catalyzing the oxidation of aldehydes to carboxylic acids. Although ALDH gene family members in various plants have been extensively studied and were found to regulate plant response to abiotic stress, reports on ALDH genes in the common bean (Phaseolus vulgaris L.) are limited. In this study, we aimed to investigate the effects of neutral (NS) and basic alkaline (AS) stresses on growth, physiological and biochemical indices, and ALDH activity, ALDH gene expression of common bean. In addition, We used bioinformatics techniques to analyze the physical and chemical properties, phylogenetic relationships, gene replication, collinearity, cis-acting elements, gene structure, motifs, and protein structural characteristics of PvALDH family members. We found that both NS and AS stresses weakened the photosynthetic performance of the leaves, induced oxidative stress, inhibited common bean growth, and enhanced the antioxidative system to scavenge reactive oxygen species. Furthermore, we our findings revealed that ALDH in the common bean actively responds to NS or AS stress by inducing the expression of PvALDH genes. In addition, using the established classification criteria and phylogenetic analysis, 27 PvALDHs were identified in the common bean genome, belonging to 10 ALDH families. The primary expansion mode of PvALDH genes was segmental duplication. Cis-acting elemental analysis showed that PvALDHs were associated with abiotic stress and phytohormonal responses. Gene expression analysis revealed that the PvALDH gene expression was tissue-specific. For instance, PvALDH3F1 and PvALDH3H1 were highly expressed in flower buds and flowers, respectively, whereas PvALDH3H2 and PvALDH2B4 were highly expressed in green mature pods and young pods, respectively. PvALDH22A1 and PvALDH11A2 were highly expressed in leaves and young trifoliates, respectively; PvALDH18B2 and PvALDH18B3 were highly expressed in stems and nodules, respectively; and PvALDH2C2 and PvALDH2C3 were highly expressed in the roots. PvALDHs expression in the roots responded positively to NS-AS stress, and PvALDH2C3, PvALDH5F1, and PvALDH10A1 were significantly (P < 0.05) upregulated in the roots. These results indicate that AS stress causes higher levels of oxidative damage than NS stress, resulting in weaker photosynthetic performance and more significant inhibition of common bean growth. The influence of PvALDHs potentially modulates abiotic stress response, particularly in the context of saline-alkali stress. These findings establish a basis for future research into the potential roles of ALDHs in the common bean.

Vascular Regenerative Cell Deficiencies in South Asian Adults

BackgroundSouth Asian individuals shoulder a disproportionate burden of cardiometabolic diseases. ObjectivesThe purpose of this study was to determine if vascular regenerative cell content varies significantly between South Asian and White European people. MethodsBetween January 2022 and January 2023, 60 South Asian and 60 White European adults with either documented cardiovascular disease or established diabetes with ≥1 other cardiovascular risk factor were prospectively enrolled. Vascular regenerative cell content in venous blood was enumerated using a flow cytometry assay that is based on high aldehyde dehydrogenase (ALDHhi) activity and cell surface marker phenotyping. The primary outcome was the difference in frequency of circulating ALDHhi progenitor cells, monocytes, and granulocytes between the 2 groups. ResultsCompared with White European participants, those of South Asian ethnicity were younger (69 ± 10 years vs 66 ± 9 years; P < 0.05), had lower weight (88 ± 19 kg vs 75 ± 13 kg; P < 0.001), and exhibited a greater prevalence of type 2 diabetes (62% vs 92%). South Asian individuals had markedly lower circulating frequencies of pro-angiogenic ALDHhiSSClowCD133+ progenitor cells (P < 0.001) and ALDHhiSSCmidCD14+CD163+ monocytes with vessel-reparative capacity (P < 0.001), as well as proportionally more ALDHhi progenitor cells with high reactive oxygen species content (P < 0.05). After correction for sex, age, body mass index, and glycated hemoglobin, South Asian ethnicity was independently associated with lower ALDHhiSSClowCD133+ cell count. ConclusionsSouth Asian people with cardiometabolic disease had less vascular regenerative and reparative cells suggesting compromised vessel repair capabilities that may contribute to the excess vascular risk in this population. (The Role of South Asian vs European Origins on Circulating Regenerative Cell Exhaustion [ORIGINS-RCE]; NCT05253521)

Integrated transcriptome and cell phenotype analysis suggest involvement of PARP1 cleavage, Hippo/Wnt, TGF-β and MAPK signaling pathways in ovarian cancer cells response to cannabis and PARP1 inhibitor treatment.

Introduction: Cannabis sativa is utilized mainly for palliative care worldwide. Ovarian cancer (OC) is a lethal gynecologic cancer. A particular cannabis extract fraction ('F7') and the Poly(ADP-Ribose) Polymerase 1 (PARP1) inhibitor niraparib act synergistically to promote OC cell apoptosis. Here we identified genetic pathways that are altered by the synergistic treatment in OC cell lines Caov3 and OVCAR3. Materials and methods: Gene expression profiles were determined by RNA sequencing and quantitative PCR. Microscopy was used to determine actin arrangement, a scratch assay to determine cell migration and flow cytometry to determine apoptosis, cell cycle and aldehyde dehydrogenase (ALDH) activity. Western blotting was used to determine protein levels. Results: Gene expression results suggested variations in gene expression between the two cell lines examined. Multiple genetic pathways, including Hippo/Wnt, TGF-β/Activin and MAPK were enriched with genes differentially expressed by niraparib and/or F7 treatments in both cell lines. Niraparib + F7 treatment led to cell cycle arrest and endoplasmic reticulum (ER) stress, inhibited cell migration, reduced the % of ALDH positive cells in the population and enhanced PARP1 cleavage. Conclusion: The synergistic effect of the niraparib + F7 may result from the treatment affecting multiple genetic pathways involving cell death and reducing mesenchymal characteristics.

ALDH Activity Assay: A Method for Cancer Stem Cell (CSC) Identification and Isolation.

Cancer stem cells (CSCs) are a small tumor cell subpopulation, driving cancer initiation, progression, multidrug resistance, and metastasis. Several methods are used to detect and isolate CSCs by flow cytometry. Among these, measurement of aldehyde dehydrogenase (ALDH) activity within the cell is an assay widely used to identify and isolate CSCs from different types of solid tumors. The aldehyde dehydrogenase (ALDH) is a polymorphic enzyme responsible for the oxidation of aldehydes to carboxylic acids, overexpressed both in normal and cancer stem cells. In this chapter, it is described how CSCs are detected and isolated by using ALDH activity assay.

ALDH1A1 drives prostate cancer metastases and radioresistance by interplay with AR- and RAR-dependent transcription.

Rationale: Current therapies for metastatic osseous disease frequently fail to provide a durable treatment response. To date, there are only limited therapeutic options for metastatic prostate cancer, the mechanisms that drive the survival of metastasis-initiating cells are poorly characterized, and reliable prognostic markers are missing. A high aldehyde dehydrogenase (ALDH) activity has been long considered a marker of cancer stem cells (CSC). Our study characterized a differential role of ALDH1A1 and ALDH1A3 genes as regulators of prostate cancer progression and metastatic growth. Methods: By genetic silencing of ALDH1A1 and ALDH1A3 in vitro, in xenografted zebrafish and murine models, and by comparative immunohistochemical analyses of benign, primary tumor, and metastatic specimens from patients with prostate cancer, we demonstrated that ALDH1A1 and ALDH1A3 maintain the CSC phenotype and radioresistance and regulate bone metastasis-initiating cells. We have validated ALDH1A1 and ALDH1A3 as potential biomarkers of clinical outcomes in the independent cohorts of patients with PCa. Furthermore, by RNAseq, chromatin immunoprecipitation (ChIP), and biostatistics analyses, we suggested the molecular mechanisms explaining the role of ALDH1A1 in PCa progression. Results: We found that aldehyde dehydrogenase protein ALDH1A1 positively regulates tumor cell survival in circulation, extravasation, and metastatic dissemination, whereas ALDH1A3 plays the opposite role. ALDH1A1 and ALDH1A3 are differentially expressed in metastatic tumors of patients with prostate cancer, and their expression levels oppositely correlate with clinical outcomes. Prostate cancer progression is associated with the increasing interplay of ALDH1A1 with androgen receptor (AR) and retinoid receptor (RAR) transcriptional programs. Polo-like kinase 3 (PLK3) was identified as a transcriptional target oppositely regulated by ALDH1A1 and ALDH1A3 genes in RAR and AR-dependent manner. PLK3 contributes to the control of prostate cancer cell proliferation, migration, DNA repair, and radioresistance. ALDH1A1 gain in prostate cancer bone metastases is associated with high PLK3 expression. Conclusion: This report provides the first evidence that ALDH1A1 and PLK3 could serve as biomarkers to predict metastatic dissemination and radiotherapy resistance in patients with prostate cancer and could be potential therapeutic targets to eliminate metastasis-initiating and radioresistant tumor cell populations.