Expression Of Aldehyde Dehydrogenase Research Articles

Low-Dose Sorafenib Promotes Cancer Stem Cell Expansion and Accelerated Tumor Progression in Soft Tissue Sarcomas.

The cancer stem cell (CSC) hypothesis postulates that heterogeneous human cancers harbor a population of stem-like cells which are resistant to cytotoxic therapies, thus providing a reservoir of relapse following conventional therapies like chemotherapy and radiation (RT). CSCs have been observed in multiple human cancers, and their presence has been correlated with worse clinical outcomes. Here, we sought to evaluate the impact of drug dosing of the multi-tyrosine kinase inhibitor, sorafenib, on CSC and non-CSCs in soft tissue sarcoma (STS) models, hypothesizing differential effects of sorafenib based on dose and target cell population. In vitro, human cancer cell lines and primary STS from surgical specimens were exposed to escalating doses of sorafenib to determine cell viability and expression of CSC marker aldehyde dehydrogenase (ALDH). In vivo, ALDHbright CSCs were isolated, exposed to sorafenib, and xenograft growth and survival analyses were performed. We observed that sarcoma CSCs appear to paradoxically respond to the tyrosine kinase inhibitor sorafenib at low doses with increased proliferation and stem-like function of CSCs, whereas anti-viability effects dominated at higher doses. Importantly, STS patients receiving neoadjuvant sorafenib and RT on a clinical trial (NCT00864032) showed increased CSCs post therapy, and higher ALDH scores post therapy were associated with worse metastasis-free survival. These data suggest that low-dose sorafenib may promote the CSC phenotype in STS with clinically significant effects, including increased tumor growth and higher rates of metastasis formation in sarcoma patients.

Gut Microbiome Mediates Ferroptosis Resistance for Colorectal Cancer Development.

Colorectal cancer is a prevalent cancer type in the United States, affecting both genders and influenced by genetics and environmental factors. The role of the gut microbiome in colorectal cancer development and therapy response is a burgeoning field of study. A recent study uncovered that trans-3-indoleacrylic acid (IDA), a microbial metabolite from P. anaerobius, promotes colorectal cancer by inhibiting ferroptosis, a type of nonapoptotic cell death driven by unrestricted lipid peroxidation and subsequent membrane damage. IDA activates aryl hydrocarbon receptor (AHR), a nuclear transcription factor, leading to the expression of aldehyde dehydrogenase 1 family member A3 (ALDH1A3). ALDH1A3, known for aldehyde detoxification, also contributes to ferroptosis resistance by generating reduced nicotinamide adenine dinucleotide (NADH), critical for the synthesis of reduced coenzyme Q10 (COQH10), by apoptosis-inducing factor mitochondria-associated 2 (AIFM2, also known as FSP1). Knocking out AHR, AIFM2, or ALDH1A3 reverses the inhibitory effect of IDA on ferroptosis and IDA-mediated tumor growth. Significantly, P. anaerobius is enriched in patients with colorectal cancer, and supplementing IDA or P. anaerobius accelerates colorectal cancer progression in spontaneous or orthotopic mouse models. Taken together, these findings suggest that targeting P. anaerobius-mediated ferroptosis resistance emerges as a promising strategy to combat colorectal cancer development.

Preclinical Evaluation of NTX-301, a Novel DNA Hypomethylating Agent in Ovarian Cancer.

DNA methylation causes silencing of tumor-suppressor and differentiation-associated genes, being linked to chemoresistance. Previous studies demonstrated that hypomethylating agents (HMA) resensitize ovarian cancer to chemotherapy. NTX-301 is a highly potent and orally bioavailable HMA, in early clinical development. The antitumor effects of NTX-301 were studied in ovarian cancer models by using cell viability, stemness and ferroptosis assays, RNA sequencing, lipidomic analyses, and stimulated Raman spectroscopy. Ovarian cancer cells (SKOV3, IC50 = 5.08 nmol/L; OVCAR5 IC50 = 3.66 nmol/L) were highly sensitive to NTX-301 compared with fallopian tube epithelial cells. NTX-301 downregulated expression of DNA methyltransferases 1-3 and induced transcriptomic reprogramming with 15,000 differentially expressed genes (DEG, P < 0.05). Among them, Gene Ontology enrichment analysis identified regulation of fatty acid biosynthesis and molecular functions related to aldehyde dehydrogenase (ALDH) and oxidoreductase, known features of cancer stem cells. Low-dose NTX-301 reduced the ALDH(+) cell population and expression of stemness-associated transcription factors. Stearoyl-coenzyme A desaturase 1 (SCD), which regulates production of unsaturated fatty acids (UFA), was among the top DEG downregulated by NTX-301. NTX-301 treatment decreased levels of UFA and increased oxidized lipids, and this was blunted by deferoxamine, indicating cell death via ferroptosis. NTX-301-induced ferroptosis was rescued by oleic acid. In vivo, monotherapy with NTX-301 significantly inhibited ovarian cancer and patient-derived xenograft growth (P < 0.05). Decreased SCD levels and increased oxidized lipids were detected in NTX-301-treated xenografts. NTX-301 is active in ovarian cancer models. Our findings point to a new mechanism by which epigenetic blockade disrupts lipid homeostasis and promotes cancer cell death.

Synergistic action of Acinetobacter baumannii and Talaromyces sp.: Function of enzymes in crude oil degradation

The purpose of this study was to explore the role of intracellular and extracellular enzymes of Acinetobacter baumannii and Talaromyces sp. in the synergistic degradation of crude oil. The extracellular enzymes of Talaromyces sp. contributed more to the degradation of n-alkanes. The degradation rate of n-hexadecane by extracellular enzymes of Talaromyces sp. was 71.83% after 5 days. The concentration of n-hexadecane decreased from 7700 mg/L to 2169 mg/L. This is related to the high extracellular expression of methane monooxygenase (particulate) and aldehyde dehydrogenase (NAD+) in Talaromyces sp. The extracellular enzymes of Acinetobacter baumannii had a better effect on the degradation of aromatic hydrocarbons. The degradation rate of xylene by extracellular enzymes of Acinetobacter baumannii was 35.65% after 5 days. The concentration of xylene decreased from 8600 mg/L to 5514 mg/L. Catechol 1,2-dioxygenase plays a key role in this process. Meanwhile, the degradation enzyme systems of Acinetobacter baumannii (long-chain alkane monooxygenase, alkane 1-monooxygenase, catechol 1,2-dioxygenase, salicylate hydroxylase, and benzoate 1,2-dioxygenase) and Talaromyces sp. (methane monooxygenase (particulate), benzaldehyde dehydrogenase (NAD+), catechol 2,3-dioxygenase, and gentisate 1,2-dioxygenase) complement each other in the degradation process of n-alkanes and aromatic hydrocarbons, thus improving the degradation ability. These results indicated that bacteria and fungi rely on the difference of degrading enzymes to achieve synergistic degradation.

Valproic acid reprograms the metabolic aberration of cisplatin treatment via ALDH modulation in triple-negative breast cancer cells.

We recently demonstrated that the histone deacetylase inhibitor valproic acid (VPA) reprograms the cisplatin-induced metabolome of triple-negative breast cancer (TNBC) cells, including a shift in hexose levels. Accordingly, here, we tested the hypothesis that VPA alters glucose metabolism in correlation with cisplatin sensitivity. Two TNBC cell lines, MDA-MB-231 (a cisplatin-resistant line) and MDA-MB-436 (a cisplatin-sensitive line), were analyzed. The glycolysis and oxidative metabolism were measured using the Glycolysis Stress Test kit. The expression of aldehyde dehydrogenases (ALDHs), enzymes linked to drug resistance, was investigated by Western blot and real-time PCR analyses. We additionally studied the influence of ALDH inhibition by disulfiram on the viability of MDA-MB-231 cells and on a TNBC patient-derived organoid system. Cisplatin treatment reduced the extracellular acidification rate in MDA-MB-436 cells but not MDA-MB-231 cells, whereas VPA addition increased the extracellular acidification rate in both cell lines. VPA further reduced the oxygen consumption rate of cisplatin-treated MDA-MB-436 cells, which correlated with cell cycle alterations. However, in MDA-MB-231 cells, the cell cycle distribution did not change between cisplatin/VPA-cisplatin treatments. In both cell lines, VPA increased the expression of ALDH isoform and ALDH1A1 expression. However, only in MDA-MB-231 cells, VPA synergized with cisplatin to augment this effect. Disulfiram sensitized the cells to the cytotoxic effects of the VPA-cisplatin combination. Furthermore, the disulfiram-VPA-chemotherapy combination was most effective in TNBC organoids. Our results show that ALDH overexpression may act as one mechanism of cellular resistance to VPA in TNBC and that its inhibition may enhance the therapeutic efficacy of VPA-chemotherapeutic drug combinations.

Investigating Carvedilol's Repurposing for the Treatment of Non-Small Cell Lung Cancer via Aldehyde Dehydrogenase Activity Modulation in the Presence of β-Adrenergic Agonists.

Repurposing existing drugs appears to be a potential solution for addressing the challenges in the treatment of non-small cell lung cancer (NSCLC). β-adrenoceptor antagonist drugs (β-blockers) have tumor-inhibiting effects, making them promising candidates for potential NSCLC treatment. This study investigates the anticancer potential of a subset of β-blockers in NSCLC cell lines; A549 and H1299. Additionally, it investigates the underlying mechanism behind β-blockers' anticancer effect by influencing a potential novel target named aldehyde dehydrogenase (ALDH). The MTT assay assessed β-blockers' cytotoxicity on both cell lines, while Western blot and NADH fluorescence assays evaluated their influence on ALDH protein expression and activity. Carvedilol (CAR) was the most effective blocker in reducing cell survival of A549 and H1299 with IC50 of 18 µM and 13.7 µM, respectively. Significantly, CAR led to a 50% reduction in ALDH expression and 80% decrease in ALDH activity in A549 cells, especially when combined with β-agonists, in comparison to the control. This effect might be attributed to β-agonist blockade or an alternative pathway. This novel finding adds to our understanding of CAR's multifaceted anticancer properties, implying that combining CAR with β-agonists could be a useful strategy for lung cancer treatment.

Cancer Stem Cells of Esophageal Adenocarcinoma are Suppressed by Inhibitors of TRPV2 and SLC12A2.

The potential of membrane transporters activated in cancer stem cells (CSCs) as new therapeutic targets for cancer is attracting increasing interest. Therefore, the present study examined the expression profiles of ion transport-related molecules in the CSCs of esophageal adenocarcinoma (EAC). Cells that highly expressed aldehyde dehydrogenase 1 family member A1 (ALDH1A1) were separated from OE33 cells, a human Barrett's EAC cell line, by fluorescence-activated cell sorting. CSCs were identified based on the formation of tumorspheres. Gene expression profiles in CSCs were examined by a microarray analysis. Among OE33 cells, ALDH1A1 messenger RNA levels were higher in CSCs than in non-CSCs. Furthermore, CSCs exhibited resistance to cisplatin and had the capacity to redifferentiate. The results of the microarray analysis of CSCs showed the up-regulated expression of several genes related to ion channels/transporters, such as transient receptor potential vanilloid 2 (TRPV2) and solute carrier family 12 member 2 (SLC12A2). The cytotoxicities of the TRPV2 inhibitor tranilast and the SLC12A2 inhibitor furosemide were higher at lower concentrations in CSCs than in non-CSCs, and both markedly reduced the number of tumorspheres. The cell population among OE33 cells that highly expressed ALDH1A1 also was significantly decreased by these inhibitors. Based on the present results, TRPV2 and SLC12A2 are involved in the maintenance of CSCs, and their specific inhibitors, tranilast and furosemide, respectively, have potential as targeted therapeutic agents for EAC.

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.

Aldehyde Dehydrogenase: An Off-Label Marker of Endothelial Activation in Oral Squamous Cell Carcinoma.

The vascular endothelial (VE) expression of aldehyde dehydrogenase (ALDH) 1/2 family in oral leukoplakia (OL) and oral squamous cell carcinoma (OSCC) cases has not been studied so far. The aim of this study was to illustrate the "off-label" endothelial expression of cancer stem cell (CSC) biomarker, ALDH1/2, adjacent to oral potentially malignant and malignant lesions in order to shed some light on the mechanisms leading to oral carcinogenesis. Materials and methods: The expression of CSC protein-biomarker ALDH1/2 was detected through immunohistochemistry (IHC) in 30 paraffin-embedded samples of OL and 21 samples of OSCC compared to five samples of normal oral mucosa. Statistical analysis was done using SPSS, Pearson Chi-square, and Fischer's exact test. The significance level was set at 0.05 (p≤ 0.05). Results: In oral mucosal vessels, ALDH1/2 was not expressed. It was expressed significantly more in the vessels of OSCCs compared to the OLs (Fisher's exact test, p-value= 0,001). However, when endothelial expression of ALDH1/2 in the vasculature of OLs was compared with that of the normal oral mucosa, no significant change was noticed (Fisher's exact test, p-value=1.000). Discussion: The IHC VE expression of ALDH1/2 in OSCCvasculature but not in OL indicates a possible significantly stronger activation of endothelial cells during carcinogenesis, which could be an indicator of the role of inflammation in the development of field cancerization and of prognostic value for (vascular/lymphatic) metastasis.

Identification and characterisation of the tegument-expressed aldehyde dehydrogenase SmALDH_312 of Schistosoma mansoni, a target of disulfiram.

Schistosomiasis is an infectious disease caused by blood flukes of the genus Schistosoma and affects approximately 200 million people worldwide. Since Praziquantel (PZQ) is the only drug for schistosomiasis, alternatives are needed. By a biochemical approach, we identified a tegumentally expressed aldehyde dehydrogenase (ALDH) of S. mansoni, SmALDH_312. Molecular analyses of adult parasites showed Smaldh_312 transcripts in both genders and different tissues. Physiological and cell-biological experiments exhibited detrimental effects of the drug disulfiram (DSF), a known ALDH inhibitor, on larval and adult schistosomes in vitro. DSF also reduced stem-cell proliferation and caused severe tegument damage in treated worms. In silico-modelling of SmALDH_312 and docking analyses predicted DSF binding, which we finally confirmed by enzyme assays with recombinant SmALDH_312. Furthermore, we identified compounds of the Medicine for Malaria Venture (MMV) pathogen box inhibiting SmALDH_312 activity. Our findings represent a promising starting point for further development towards new drugs for schistosomiasis.

Prognostic biomarkers in and selection of surgical patients with hepatocellular carcinoma.

Prognostic biomarkers in and selection of surgical patients with hepatocellular carcinoma.

Abstract 5797: NTX301, a novel DNA hypomethylating agent, targets lipid metabolism in ovarian cancer

Abstract Background: DNA methylation causes the silencing of tumor suppressor and differentiation-associated genes being linked to chemoresistance and stemness. Previous studies demonstrated that hypomethylating agents (HMA) re-sensitize ovarian cancer (OC) cells to chemotherapy, however, translation to the clinic has been slow. NTX 301 (PinotBio) is a novel, highly potent, and orally bioavailable HMA, in early clinical development. Methods: We assessed the anti-tumor effects of NTX301 in OC models and studied the underlying molecular mechanisms by using cell proliferation, stemness, and ferroptosis assays, RNA sequencing, and validation. Results: OC cells (SKOV3, IC50=5.089nM; OVCAR5 IC50=3.664nM) were highly sensitive to NTX301 (p&amp;lt;0.05) compared to immortalized fallopian tube epithelial cells (FT-190) (IC50=103.3nM). Treatment with NTX301 induced significant downregulation of the DNA methyltransferases (DNMTs) 1-3 expression in SKOV3 and OVCAR5 cells compared with decitabine (p&amp;lt;0.05). Treatment with low dose NTX301 (100nM) induced significant transcriptomic reprogramming with 15,000 differentially expressed genes (DEGs) compared to DMSO (p&amp;lt;0.05). Among the NTX301 down-regulated DEGs, Gene Ontology (GO) enrichment analysis identified pathways related to the regulation of alcohol, cholesterol, and fatty acid biosynthetic process and molecular functions related to aldehyde dehydrogenase (ALDH) and oxidoreductase activity, known features of cancer stem cells (CSCs). Indeed, treatment with low dose NTX301 (100nM) reduced the ALDH(+) cell population and expression of stemness-associated transcription factors (Oct4 and Sox2). Additionally, stearoyl-Coenzyme A desaturase 1 (SCD), a key enzyme that regulates unsaturated fatty acid homeostasis in the lipogenesis process was found among the top DEGs downregulated in response to NTX3 (fold change=9.36, FDR&amp;lt;0.05). As blockade of SCD had been shown to induce ferroptosis, oxidized lipids levels were measured by C11-BODIPY staining. NTX301 treatment increased the levels of oxidized lipids compared to DMSO and this was blunted by deferoxamine, indicating that NTX301 promoted cell death via ferroptosis. NTX301-induced ferroptosis was successfully rescued by the addition of oleic acid (200μM) into the culture medium, supporting that it was mediated through SCD depletion. In vivo, monotherapy with NTX301 (0.5mg/kg), significantly inhibited subcutaneous OC xenograft tumor growth (p&amp;lt;0.05). Decreased SCD levels and increased oxidized lipids were recorded in NTX301-treated xenografts. Conclusions: NTX301 is a potent HMA active in OC models. Our findings point to a new mechanism by which epigenetic blockade disrupts lipid homeostasis and promotes cancer cell death. Citation Format: Yinu Wang, Xiaolei Situ, Horacio Cardenas, Daniela Matei, Ellie Siu, Sayedabdulrazzaq A. Alhunayan. NTX301, a novel DNA hypomethylating agent, targets lipid metabolism in ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5797.

Analyses of leaf morphological changes and expressed genes related to water shortage of Fagus orientalis populations in a drought gradient

Climate change models predict an increase in mean annual temperature, a decrease in precipitation and consequently a scarcity of water resources during the growing season for Iran, including the northern forests of the country. One of the consequences is increased water shortage stress during the summer season. Fagus orientalis Lipsky is one of the most important commercial broad leaf species in the Hyrcanian forests and its potential of phenotypic and genetic adaptation to the climate change is essentially vital. The present research was carried out along two precipitation gradients from very humid to semi-humid conditions on four beech populations. The results of the flexibility of the leaf morphological traits showed that the populations of dryer regions had smaller and more elongated leaves than other populations. Evaluation of the expression of seven candidate genes in response to water shortage showed that the expression of aldehyde dehydrogenase, ascorbate peroxidase, Dehydrin (DHN), early responsive to dehydration, late embryogenesis abundant and Cys/His-Type Zinc-Finger in the eastern population was higher than that in the western population, while a difference in elevation gradient was only observed in the expression of some genes. Therefore, the natural selection pressure in the past evolutionary periods in the westeast gradient seems to be higher than the elevation gradient and has led to greater resistance to drought. Principal component analysis revealed that aldehyde dehydrogenase genes (ALDH), early responsive to dehydration (ERD), late embryogenesis abundant (LEA) and DHN are the most effective genes responding to water shortage stress for Oriental beech in the Hyrcanian forests. Keywords: drought gradient, Fagus orientalis, gene expression, leaf morphology

13-Oxo-9Z,11E-octadecadienoic Acid Down-regulates c-Myc and Attenuates Breast Cancer Cell Stemness.

Breast cancer stem cells (BCSCs) are involved in the development of breast cancer and contribute to therapeutic resistance. This study aimed to investigate the anticancer stem cell (CSC) mechanism of 13-Oxo-9Z,11E-octadecadienoic acid (13-Oxo-ODE) as a potent CSC inhibitor in breast cancer. The effects of 13-Oxo-ODE on BCSCs were evaluated using a mammosphere formation assay, CD44high/CD24low analysis, aldehyde dehydrogenase (ALDH) assay, apoptosis assay, quantitative real-time PCR, and western blotting. We found that 13-Oxo-ODE suppressed cell proliferation, CSC formation, and mammosphere proliferation and increased apoptosis of BCSCs. Additionally, 13-Oxo-ODE reduced the subpopulation of CD44high/CD24low cells and ALDH expression. Furthermore, 13-Oxo-ODE decreased c-myc gene expression. These results suggest that 13-Oxo-ODE has potential as a natural inhibitor targeting BCSCs through the degradation of c-Myc. In summary, 13-Oxo-ODE induced CSC death possibly through reduced c-Myc expression, making it a promising natural inhibitor of BCSCs.

Unbalance between Pyridine Nucleotide Cofactors in The SOD1 Deficient Yeast Saccharomyces cerevisiae Causes Hypersensitivity to Alcohols and Aldehydes.

Alcohol and aldehyde dehydrogenases are especially relevant enzymes involved in metabolic and detoxification reactions that occur in living cells. The comparison between the gene expression, protein content, and enzymatic activities of cytosolic alcohol and aldehyde dehydrogenases of the wild-type strain and the Δsod1 mutant lacking superoxide dismutase 1, which is hypersensitive to alcohols and aldehydes, shows that the activity of these enzymes is significantly higher in the Δsod1 mutant, but this is not a mere consequence of differences in the enzymatic protein content nor in the expression levels of genes. The analysis of the NAD(H) and NADP(H) content showed that the higher activity of alcohol and aldehyde dehydrogenases in the Δsod1 mutant could be a result of the increased availability of pyridine nucleotide cofactors. The higher level of NAD+ in the Δsod1 mutant is not related to the higher level of tryptophan; in turn, a higher generation of NADPH is associated with the upregulation of the pentose phosphate pathway. It is concluded that the increased sensitivity of the Δsod1 mutant to alcohols and aldehydes is not only a result of the disorder of redox homeostasis caused by the induction of oxidative stress but also a consequence of the unbalance between pyridine nucleotide cofactors.

Chromium (VI) promotes lung cancer initiation by activating EGF/ALDH1A1 signalling.

Lung cancer is the leading cause of cancer-related death worldwide and is strongly associated with tobacco smoke exposure. Though smoking remains the most important and best studied risk factor, recent data suggests that several other carcinogens have a driving role in lung cancer development, particularly in select populations at risk of high or prolonged exposure. Hexavalent chromium [Cr(VI)] is a known carcinogen that is widely used in the manufacturing industry. While the link between Cr(VI) and lung cancer incidence is well-accepted, the mechanisms through which Cr(VI) promotes lung cancer development are poorly understood. In the present study by Ge and colleagues published in Clinical and Translational Medicine, the authors explored the effects of prolonged Cr(VI) on non-malignant lung epithelial cells. They determined that Cr(VI) initiates lung tumorigenesis by transforming a subpopulation of stem-like, tumor initiating cells with increased expression of Aldehyde dehydrogenase 1 family member A1 (ALDH1A1). The observed increase in ALDH1A1 was dependent on transcriptional upregulation via Krüppel-like factor 4 (KLF4), and associated with enhanced Epidermal Growth Factor (EGF) biosynthesis. Cr(VI)-transformed tumor initiating cells accelerated tumor formation in vivo, which was ameliorated by therapeutic inhibition of ALDH1A1. Importantly, ALDH1A1 inhibition also sensitized Cr(VI)-driven tumors to Gemcitabine chemotherapy and extended overall survival in mice. This study not only offers novel insight into the mechanisms through which Cr(VI) exposure initiates lung tumorigenesis, but identifies a potential therapeutic target for patients with lung cancer secondary to Cr(VI) exposure. Additionally, this study underscores the importance of limiting exposure to Cr(VI) in the workplace and finding safer alternatives for use in the manufacturing industry.

PTEN overexpression and nuclear β-catenin stabilization promote morular differentiation through induction of epithelial–mesenchymal transition and cancer stem cell-like properties in endometrial carcinoma

BackgroundAlthough a lack of functional PTEN contributes to tumorigenesis in a wide spectrum of human malignancies, little is known about the functional role of its overexpression in the tumors. The current study focused on PTEN overexpression in endometrial carcinoma (Em Ca).MethodsThe functional impact of PTEN overexpression was assessed by Em Ca cell lines. Immunohistochemical analyses were also conducted using 38 Em Ca with morular lesions.ResultsEm Ca cell lines stably overexpressing PTEN (H6-PTEN) exhibited epithelial–mesenchymal transition (EMT)-like features, probably through β-catenin/Slug-meditated suppression of E-cadherin. PTEN overexpression also inhibited cell proliferation, accelerated cellular senescence, increased apoptotic features, and enhanced migration capability. Moreover, H6-PTEN cells exhibited cancer stem cell (CSC)-like properties, along with high expression of aldehyde dehydrogenase 1 and CD44s, a large ALDH 1high population, enriched spheroid formation, and β-catenin-mediated upregulation of cyclin D2, which is required for persistent CSC growth. In clinical samples, immunoreactivities for PTEN, as well as CSC-related molecules, were significantly higher in morular lesions as compared to the surrounding carcinomas. PTEN score was positively correlated with expression of nuclear β-catenin, cytoplasmic CD133, and CD44v6, and negatively with cell proliferation. Finally, estrogen receptor-α (ERα)-dependent expression of Ezrin-radixin-moesin-binding phophoprotein-50 (EBP50), a multifunctional scaffolding protein, acts as a negative regulator of morular formation by Em Ca cells through interacting with PTEN and β-catenin.ConclusionIn the abscess of ERα/EBP50 expression, PTEN overexpression and nuclear β-catenin stabilization promote the establishment and maintenance of morular phenotype associated with EMT/CSC-like features in Em Ca cells.BZqz53M46AEhaXf_YNaSmyVideo

Targeting aldehyde dehydrogenase for prostate cancer therapies.

Prostate cancer (PCa) is the most common cancer in men in the United States. About 10 – 20% of PCa progress to castration-resistant PCa (CRPC), which is accompanied by metastasis and therapeutic resistance. Aldehyde dehydrogenase (ALDH) is famous as a marker of cancer stem-like cells in different cancer types, including PCa. Generally, ALDHs catalyze aldehyde oxidation into less toxic carboxylic acids and give cancers a survival advantage by reducing oxidative stress caused by aldehyde accumulation. In PCa, the expression of ALDHs is associated with a higher tumor stage and more lymph node metastasis. Functionally, increased ALDH activity makes PCa cells gain more capabilities in self-renewal and metastasis and reduces the sensitivity to castration and radiotherapy. Therefore, it is promising to target ALDH or ALDHhigh cells to eradicate PCa. However, challenges remain in moving the ALDH inhibitors to PCa therapy, potentially due to the toxicity of pan-ALDH inhibitors, the redundancy of ALDH isoforms, and the lack of explicit understanding of the metabolic signaling transduction details. For targeting PCa stem-like cells (PCSCs), different regulators have been revealed in ALDHhigh cells to control cell proliferation and tumorigenicity. ALDH rewires essential signaling transduction in PCa cells. It has been shown that ALDHs produce retinoic acid (RA), bind with androgen, and modulate diverse signaling. This review summarizes and discusses the pathways directly modulated by ALDHs, the crucial regulators that control the activities of ALDHhigh PCSCs, and the recent progress of ALDH targeted therapies in PCa. These efforts will provide insight into improving ALDH-targeted treatment.

Isothiocyanates (ITCs) 1-(Isothiocyanatomethyl)-4-phenylbenzene and 1-Isothiocyanato-3,5-bis(trifluoromethyl)benzene-Aldehyde Dehydrogenase (ALDH) Inhibitors, Decreases Cisplatin Tolerance and Migratory Ability of NSCLC.

One of the main treatment modalities for non-small-cell lung cancer (NSCLC) is cisplatin-based chemotherapy. However, the acquisition of cisplatin resistance remains a major problem. Existing chemotherapy regimens are often ineffective against cancer cells expressing aldehyde dehydrogenase (ALDH). As such, there is an urgent need for therapies targeting ALDH-positive cancer cells. The present study compares the anticancer properties of 36 structurally diverse isothiocyanates (ITCs) against NSCLC cells with the ALDH inhibitor disulfiram (DSF). Their potential affinity to ALDH isoforms and ABC proteins was assessed using AutoDockTools, allowing for selection of three compounds presenting the strongest affinity to all tested proteins. The selected ITCs had no impact on NSCLC cell viability (at tested concentrations), but significantly decreased the cisplatin tolerance of cisplatin-resistant variant of A549 (A549CisR) and advanced (stage 4) NSCLC cell line H1581. Furthermore, long-term supplementation with ITC 1-(isothiocyanatomethyl)-4-phenylbenzene reverses the EMT phenotype and migratory potential of A549CisR to the level presented by parental A549 cells, increasing E-Cadherin expression, followed by decreased expression of ABCC1 and ALDH3A1. Our data indicates that the ALDH inhibitors DSF and ITCs are potential adjuvants of cisplatin chemotherapy.

Abstract 6063: FOXK2 promotes stemness in ovarian cancer by regulating unfolded protein response signaling

Abstract Introduction: Cancer stem cells (CSCs), a rare cell population within tumors that possesses self-renewal and tumor initiation capacity, have been implicated in cancer relapse and resistance to chemotherapy. In ovarian cancer (OC), CSCs are characterized by a high expression of aldehyde dehydrogenase (ALDH). Understanding the regulatory programs promoting stemness could identify new treatments. We identified FOXK2 as a key transcription factor (TF) that promotes stemness in OC. Methods: We generated FOXK2 knockdown OC models by stable transduction of shRNA targeting this TF and measured the population of ALDH+ CSCs, expression of stemness-associated genes, and in vivo tumor initiation capacities. Transcriptomic and ChIP-seq analyses were used to identify key FOXK2 targets. CRISPR-dCas9 genome editing was used to verify the regulatory function of FOXK2. Rescue experiments validated the roles of a newly discovered target gene of FOXK2. Results: Through gene expression analyses in CSCs vs. non-CSCs, we identified FOXK2 as a highly expressed stemness-specific TF in OC. Genetic depletion of FOXK2 diminished stemness features and reduced in vivo tumor initiation capacity. Through ChIP-sequencing we discovered that FOXK2 directly regulates IRE1α (ERN1 gene) expression, a key sensor for the unfolded protein response (UPR). ChIP-sequencing analysis further revealed that FOXK2 binds to an intronic regulatory element of ERN1. Blocking FOXK2 from binding to this enhancer by using a CRISPR/dCas9 diminished IRE1α transcription. At the molecular level, FOXK2-driven upregulation of IRE1α led to alternative XBP1 mRNA splicing and activation of stemness pathways, while genetic or pharmacological blockade of IRE1α inhibited CSCs in OC models. Conclusion: Our data establish a new function for FOXK2 as a key transcriptional regulator of CSCs and a mediator of the UPR, providing insight into potentially targetable new pathways in ovarian CSCs. Citation Format: Yaqi Zhang, Yinu Wang, Guangyuan Zhao, Edward J. Tanner, Mazhar Adli, Daniela E. Matei. FOXK2 promotes stemness in ovarian cancer by regulating unfolded protein response signaling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6063.