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1.
Sci Rep ; 14(1): 15554, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38969654

RESUMO

Human hallmarks of sarcopenia include muscle weakness and a blunted response to exercise. Nicotinamide N-methyltransferase inhibitors (NNMTis) increase strength and promote the regenerative capacity of aged muscle, thus offering a promising treatment for sarcopenia. Since human hallmarks of sarcopenia are recapitulated in aged (24-month-old) mice, we treated mice from 22 to 24 months of age with NNMTi, intensive exercise, or a combination of both, and compared skeletal muscle adaptations, including grip strength, longitudinal running capacity, plantarflexor peak torque, fatigue, and muscle mass, fiber type, cross-sectional area, and intramyocellular lipid (IMCL) content. Exhaustive proteome and metabolome analyses were completed to identify the molecular mechanisms underlying the measured changes in skeletal muscle pathophysiology. Remarkably, NNMTi-treated aged sedentary mice showed ~ 40% greater grip strength than sedentary controls, while aged exercised mice only showed a 20% increase relative to controls. Importantly, the grip strength improvements resulting from NNMTi treatment and exercise were additive, with NNMTi-treated exercised mice developing a 60% increase in grip strength relative to sedentary controls. NNMTi treatment also promoted quantifiable improvements in IMCL content and, in combination with exercise, significantly increased gastrocnemius fiber CSA. Detailed skeletal muscle proteome and metabolome analyses revealed unique molecular mechanisms associated with NNMTi treatment and distinct molecular mechanisms and cellular processes arising from a combination of NNMTi and exercise relative to those given a single intervention. These studies suggest that NNMTi-based drugs, either alone or combined with exercise, will be beneficial in treating sarcopenia and a wide range of age-related myopathies.


Assuntos
Envelhecimento , Músculo Esquelético , Nicotinamida N-Metiltransferase , Condicionamento Físico Animal , Sarcopenia , Animais , Nicotinamida N-Metiltransferase/metabolismo , Músculo Esquelético/metabolismo , Músculo Esquelético/efeitos dos fármacos , Camundongos , Envelhecimento/fisiologia , Sarcopenia/metabolismo , Sarcopenia/tratamento farmacológico , Masculino , Força Muscular/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Inibidores Enzimáticos/farmacologia
2.
Hum Cell ; 37(3): 729-738, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38504052

RESUMO

Merkel cell carcinoma (MCC) is an aggressive skin cancer, with a propensity for early metastasis. Therefore, early diagnosis and the identification of novel targets become fundamental. The enzyme nicotinamide N-methyltransferase (NNMT) catalyzes the reaction of N-methylation of nicotinamide and other analogous compounds. Although NNMT overexpression was reported in many malignancies, the significance of its dysregulation in cancer cell phenotype was partly clarified. Several works demonstrated that NNMT promotes cancer cell proliferation, migration, and chemoresistance. In this study, we investigated the possible involvement of this enzyme in MCC. Preliminary immunohistochemical analyses were performed to evaluate NNMT expression in MCC tissue specimens. To explore the enzyme function in tumor cell metabolism, MCC cell lines have been transfected with plasmids encoding for short hairpin RNAs (shRNAs) targeting NNMT mRNA. Preliminary immunohistochemical analyses showed elevated NNMT expression in MCC tissue specimens. The effect of enzyme downregulation on cell proliferation, migration, and chemosensitivity was then evaluated through MTT, trypan blue, and wound healing assays. Data obtained clearly demonstrated that NNMT knockdown is associated with a decrease of cell proliferation, viability, and migration, as well as with enhanced sensitivity to treatment with chemotherapeutic drugs. Taken together, these results suggest that NNMT could represent an interesting MCC biomarker and a promising target for targeted anti-cancer therapy.


Assuntos
Carcinoma de Célula de Merkel , Neoplasias Cutâneas , Humanos , Nicotinamida N-Metiltransferase/genética , Nicotinamida N-Metiltransferase/metabolismo , Carcinoma de Célula de Merkel/genética , Resistencia a Medicamentos Antineoplásicos/genética , Proliferação de Células/genética , Neoplasias Cutâneas/tratamento farmacológico , Neoplasias Cutâneas/genética , RNA Interferente Pequeno/genética
3.
Eur J Clin Invest ; 54(6): e14185, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38426563

RESUMO

BACKGROUND: Osteosarcoma (OS) is a primary bone malignancy that mostly affects young people, characterized by high metastatic potential, and a marked chemoresistance that is responsible for disease relapse in most patients. Therefore, it is necessary to identify novel molecules to setup targeted strategies to improve the clinical outcome. The enzyme nicotinamide N-methyltransferase (NNMT) catalyses the N-methylation of nicotinamide and other analogs, playing a crucial role in the biotransformation of drugs and xenobiotics. NNMT overexpression was reported in a wide variety of cancers, and several studies demonstrated that is able to promote cell proliferation, migration and resistance to chemotherapy. The aim of this study was to explore the potential involvement of NNMT in OS. METHODS: Immunohistochemical analyses have been performed to evaluate NNMT expression in selected OS and healthy bone tissue samples. Subsequently, OS cell lines have been transfected with vectors targeting NNMT mRNA (shRNAs) and the impact of this downregulation on migration, cell proliferation, and response to chemotherapeutic treatment was also analysed by wound healing, MTT, SRB and Trypan blue assays, respectively. RESULTS: Results showed that OS samples display a significantly higher NNMT expression compared with healthy tissue. Preliminary results suggest that NNMT silencing in OS cell lines is associated to a decrease of cell proliferation and migration, as well as to enhanced sensitivity to chemotherapy. Data obtained showed that NNMT may represent an interesting marker for OS detection and a promising target for effective anti-cancer therapy.


Assuntos
Neoplasias Ósseas , Nicotinamida N-Metiltransferase , Osteossarcoma , Adolescente , Adulto , Criança , Feminino , Humanos , Masculino , Adulto Jovem , Neoplasias Ósseas/genética , Neoplasias Ósseas/metabolismo , Neoplasias Ósseas/patologia , Neoplasias Ósseas/tratamento farmacológico , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Resistencia a Medicamentos Antineoplásicos/genética , Nicotinamida N-Metiltransferase/metabolismo , Nicotinamida N-Metiltransferase/genética , Osteossarcoma/genética , Osteossarcoma/patologia , Osteossarcoma/metabolismo , Osteossarcoma/tratamento farmacológico , RNA Interferente Pequeno/genética
4.
Anticancer Res ; 44(4): 1653-1660, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38537979

RESUMO

BACKGROUND/AIM: "Stromal high expression" of Nicotinamide N-methyltransferase (NNMT), previously reported as a poor prognostic factor of gastric cancer, was based on immunohistochemical H-score. However, this could simply indicate an increase in cancer-associated fibroblasts (CAFs) because NNMT is positive for fibroblasts. To verify this, the proportion and staining intensity of stromal NNMT-positive stellate/spindle cells were evaluated separately and examined for its association with related proteins (H3K4me3, H3K27me3, and LOXL2). PATIENTS AND METHODS: Immunohistochemistry for NNMT, H3K4me3, H3K27me3, and LOXL2 was performed on 521 tissue microarrays of gastric cancer. Cancer stromal stellate/spindle cells were evaluated according to morphology, proportion, and stain intensity of NNMT, loss of H3K4me3 and H3K27me3, and stain intensity of LOXL2. Their associations with clinicopathological characteristics and overall survival were examined. RESULTS: Higher staining intensity of NNMT was not related to a poorer prognosis. However, higher proportion of NNMT-positive stellate/spindle cells indirectly contributed to a poor prognosis. It was associated with CAF-like morphology and a global decrease in H3K4me3/H3K27me3, which were both associated with high LOXL2 expression. These three factors were independent poor prognostic factors. In addition, in the LOXL2-high group, prognosis significantly deteriorated with the presence of a global decrease in H3K4me3/H3K27me3. CONCLUSION: The higher proportion of NNMT-positive cancer stromal cells in gastric cancer serves as an indicator for identifying unfavorable prognostic CAFs that show a global decrease in H3K4me3/H3K27me3. This facilitates research on the nature of these cells and their characteristics.


Assuntos
Fibroblastos Associados a Câncer , Neoplasias Gástricas , Humanos , Histonas , Nicotinamida N-Metiltransferase/metabolismo , Fibroblastos Associados a Câncer/metabolismo , Prognóstico , Células Estromais/metabolismo
5.
ACS Chem Biol ; 19(1): 89-100, 2024 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-38181447

RESUMO

Unconventional S-adenosyl-L-methionine (SAM) mimics with enhanced hydrophobicity are an adaptable building block to develop cell-potent inhibitors for SAM-dependent methyltransferases as targeted therapeutics. We recently discovered cell-potent bisubstrate inhibitors for nicotinamide N-methyltransferase (NNMT) by using an unconventional SAM mimic. To delve into the selectivity implications of the unconventional SAM mimic, we employed a chemoproteomic approach to assess two potent NNMT inhibitors LL320 (Ki, app = 6.8 nM) and II399 (containing an unconventional SAM mimic, Ki, app = 5.9 nM) within endogenous proteomes. Our work began with the rational design and synthesis of immobilized probes 1 and 2, utilizing LL320 and II399 as parent compounds. Systematic analysis of protein networks associated with these probes revealed a comprehensive landscape. Notably, NNMT emerged as the top-ranking hit, substantiating the high selectivity of both inhibitors. Meanwhile, we identified additional interacting proteins for LL320 (38) and II399 (17), showcasing the intricate selectivity profiles associated with these compounds. Subsequent experiments confirmed LL320's interactions with RNMT, DPH5, and SAHH, while II399 exhibited interactions with SHMT2 and MEPCE. Importantly, incorporating the unconventional SAM mimic in II399 led to improved selectivity compared to LL320. Our findings underscore the importance of selectivity profiling and validate the utilization of the unconventional SAM mimic as a viable strategy to create highly selective and cell-permeable inhibitors for SAM-dependent methyltransferases.


Assuntos
Inibidores Enzimáticos , S-Adenosilmetionina , Inibidores Enzimáticos/química , S-Adenosilmetionina/metabolismo , Nicotinamida N-Metiltransferase/metabolismo , Metiltransferases
6.
Bioorg Chem ; 143: 106963, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38048700

RESUMO

Nicotinamide N-methyltransferase (NNMT) catalyzes the transfer of a methyl group from S-adenosylmethionine (SAM) to nicotinamide (NAM) and other pyridine-related compounds and is involved in various metabolic processes in the human body. In addition, abnormal expression of NNMT occurs under various pathological conditions such as cancer, diabetes, metabolic disorders, and neurodegenerative diseases, making it a promising drug target worthy of in-depth research. Small-molecule NNMT inhibitors with high potency and selectivity are necessary chemical tools to test biological hypotheses and potential therapies. In this study, we developed a series of highly active NNMT inhibitors by modifying N7 position of adenine. Among them, compound 3-12 (IC50 = 47.9 ± 0.6 nM) exhibited potent inhibitory activity and also had an excellent selectivity profile over a panel of human methyltransferases. We showed that the N7 position of adenine in the NNMT bisubstrate inhibitor was a modifiable site, thus offering insights into the development of NNMT inhibitors.


Assuntos
Nicotinamida N-Metiltransferase , Tubercidina , Humanos , Nicotinamida N-Metiltransferase/química , Nicotinamida N-Metiltransferase/metabolismo , Tubercidina/metabolismo , Niacinamida/farmacologia , Adenina , Metabolismo Secundário
7.
Adv Sci (Weinh) ; 11(9): e2305907, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38126621

RESUMO

Cell cycle dysregulation is a defining feature of breast cancer. Here, 1-methyl-nicotinamide (1-MNA), metabolite of nicotinamide N-methyltransferase(NNMT) is identified, as a novel driver of cell-cycle progression in breast cancer. NNMT, highly expressed in breast cancer tissues, positively correlates with tumor grade, TNM stage, Ki-67 index, and tumor size. Ablation of NNMT expression dramatically suppresses cell proliferation and causes cell-cycle arrest in G0/G1 phase. This phenomenon predominantly stems from the targeted action of 1-MNA, resulting in a specific down-regulation of p27 protein expression. Mechanistically, 1-MNA expedites the degradation of p27 proteins by enhancing cullin-1 neddylation, crucial for the activation of Cullin-1-RING E3 ubiquitin ligase(CRL1)-an E3 ubiquitin ligase targeting p27 proteins.  NNMT/1-MNA specifically up-regulates the expression of UBC12, an E2 NEDD8-conjugating enzyme required for cullin-1 neddylation. 1-MNA showes high binding affinity to UBC12, extending the half-life of UBC12 proteins via preventing their localization to lysosome for degradation. Therefore, 1-MNA is a bioactive metabolite that promotes breast cancer progression by reinforcing neddylation pathway-mediated p27 degradation. The study unveils the link between NNMT enzymatic activity with cell-cycle progression, indicating that 1-MNA may be involved in the remodeling of tumor microenvironment.


Assuntos
Neoplasias da Mama , Proteínas Culina , Humanos , Feminino , Proteínas Culina/metabolismo , Proteína NEDD8/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Processamento de Proteína Pós-Traducional , Microambiente Tumoral , Nicotinamida N-Metiltransferase/metabolismo
8.
PeerJ ; 11: e16301, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37953778

RESUMO

Background: Chronic kidney disease (CKD) is a significant global health issue characterized by progressive loss of kidney function. Renal interstitial fibrosis (TIF) is a common feature of CKD, but current treatments are seldom effective in reversing TIF. Nicotinamide N-methyltransferase (NNMT) has been found to increase in kidneys with TIF, but its role in renal fibrosis is unclear. Methods: Using mice with unilateral ureteral obstruction (UUO) and cultured renal interstitial fibroblast cells (NRK-49F) stimulated with transforming growth factor-ß1 (TGF-ß1), we investigated the function of NNMT in vivo and in vitro. Results: We performed single-cell transcriptome sequencing (scRNA-seq) on the kidneys of mice and found that NNMT increased mainly in fibroblasts of UUO mice compared to sham mice. Additionally, NNMT was positively correlated with the expression of renal fibrosis-related genes after UUO injury. Knocking down NNMT expression reduced fibroblast activation and was accompanied by an increase in DNA methylation of p53 and a decrease in its phosphorylation. Conclusions: Our findings suggest that chronic kidney injury leads to an accumulation of NNMT, which might decrease p53 methylation, and increase the expression and activity of p53. We propose that NNMT promotes fibroblast activation and renal fibrosis, making NNMT a novel target for preventing and treating renal fibrosis.


Assuntos
Nicotinamida N-Metiltransferase , Insuficiência Renal Crônica , Obstrução Ureteral , Fibrose , Rim/metabolismo , Nicotinamida N-Metiltransferase/genética , Insuficiência Renal Crônica/genética , Proteína Supressora de Tumor p53/metabolismo , Obstrução Ureteral/genética , Animais , Camundongos
9.
Aging (Albany NY) ; 15(21): 11860-11874, 2023 10 25.
Artigo em Inglês | MEDLINE | ID: mdl-37889548

RESUMO

Elucidating the mechanism for the high metastasis capacity of Endometrial cancer (EC) is crucial to improve treatment outcomes of EC. We have recently reported that nicotinamide N-methyltransferase (NNMT) is overexpressed in EC, especially in EC, and predicts poor survival of chemotherapy patients. Here, we aimed to determine the function and mechanism of NNMT on metastasis of EC. Additionally, analysis of public datasets indicated that NNMT is involved in cholesterol metabolism. In vitro, NNMT overexpression promoted migration and invasion of EC by reducing cholesterol levels in the cytoplasm and cell membrane. Mechanistically, NNMT activated ABCA1 expression, leading to cholesterol efflux and membrane fluidity enhancement, thereby promoting EC's epithelial-mesenchymal transition (EMT). In vivo, the metastasis capacity of EC was weakened by targeting NNMT. Our findings suggest a new molecular mechanism involving NNMT in metastasis, poor survival of EC mediated by PP2A and affecting cholesterol metabolism.


Assuntos
Neoplasias do Endométrio , Fluidez de Membrana , Feminino , Humanos , Neoplasias do Endométrio/patologia , Membrana Celular/metabolismo , Colesterol , Lipídeos , Nicotinamida N-Metiltransferase/metabolismo , Transportador 1 de Cassete de Ligação de ATP
10.
Int J Mol Sci ; 24(19)2023 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-37834386

RESUMO

The high recurrence rate and invasive diagnostic and monitoring methods in bladder cancer (BCa) clinical management require the development of new non-invasive molecular tools for early detection, particularly for low-grade and low-stage BCa as well as for risk stratification. By using an in-solution digestion method and label-free data-independent LC-MS/MS coupled with ion mobility, we profiled the BCa tissues from initiation to advanced stages and confidently identified and quantified 1619 proteins (≥2 peptides). A statistically significant difference in abundance (Anova ≤ 0.05) showed 494 proteins. Significant correlation with stage with steady up or down with BCa stages showed 15 proteins. Testing of NNMT, GALK1, and HTRA1 in urine samples showed excellent diagnostic potential for NNMT and GALK1 with AUC of 1.000 (95% CI: 1.000-1.000; p < 0.0001) and 0.801 (95% CI: 0.655-0.947; p < 0.0001), respectively. NNMT and GALK1 also showed very good potential in discriminating non-invasive low-grade from invasive high-grade BCa with AUC of 0.763 (95% CI: 0.606-0.921; p = 0.001) and 0.801 (95% CI: 0.653-0.950; p < 0.0001), respectively. The combination of NNMT and GALK1 increased prognostic accuracy (AUC = 0.813). Our results broaden the range of potential novel candidates for non-invasive BCa diagnosis and prognosis.


Assuntos
Proteômica , Neoplasias da Bexiga Urinária , Humanos , Biomarcadores Tumorais/urina , Cromatografia Líquida , Detecção Precoce de Câncer , Nicotinamida N-Metiltransferase , Espectrometria de Massas em Tandem , Neoplasias da Bexiga Urinária/metabolismo
11.
Protein Pept Lett ; 30(9): 734-742, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37622714

RESUMO

INTRODUCTION: Nicotinamide N-methyltransferase (NNMT) catalyzes the N-methylation of nicotinamide with S-adenosine-L-methionine (SAM) as the methyl donor. Abnormal expression of NNMT is associated with many diseases (such as multiple cancers and metabolic and liver diseases), making NNMT a potential therapeutic target. Limited studies concerning the enzymesubstrate/ inhibitor interactions could be found to fully understand the detailed reaction mechanism. METHODS: The binding affinity and ligand binding epitopes of nicotinamide or SAH for binding NNMT and its mutants were determined using saturated transfer difference (STD) nuclear magnetic resonance (NMR) techniques combined with site-directed mutagenesis. RESULTS: The average dissociation constant of WT NNMT with nicotinamide and S-adenosine homocysteine (SAH) was 5.5 ± 0.9 mM and 1.2 ± 0.3 mM, respectively, while the mutants Y20F and Y20G with nicotinamide were up to nearly 4 times and 20 times that of WT and with SAH nearly 2 times and 5 times that of WT. The data suggested that WT had the highest binding affinity for nicotinamide or SAH, followed by Y20F and Y20G, which was consistent with its catalytic activity. CONCLUSION: The binding affinity of nicotinamide and SAH to NNMT and its mutants were obtained by STD NMR in this study. It was found that nicotinamide and SAH bind to WT in a particular orientation, and Y20 is critical for their binding orientation and affinity to NNMT.


Assuntos
Niacinamida , Nicotinamida N-Metiltransferase , Nicotinamida N-Metiltransferase/genética , Nicotinamida N-Metiltransferase/química , Ligantes , Niacinamida/química , Niacinamida/metabolismo , Adenosina , Espectroscopia de Ressonância Magnética
12.
J Biol Chem ; 299(8): 105027, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37423298

RESUMO

Metabolism controls cellular phenotype and fate. In this report, we demonstrate that nicotinamide N-methyltransferase (NNMT), a metabolic enzyme that regulates developmental stem cell transitions and tumor progression, is highly expressed in human idiopathic pulmonary fibrosis (IPF) lungs, and is induced by the pro-fibrotic cytokine, transforming growth factor-ß1 (TGF-ß1) in lung fibroblasts. NNMT silencing reduces the expression of extracellular matrix proteins, both constitutively and in response to TGF-ß1. Furthermore, NNMT controls the phenotypic transition from homeostatic, pro-regenerative lipofibroblasts to pro-fibrotic myofibroblasts. This effect of NNMT is mediated, in part, by the downregulation of lipogenic transcription factors, TCF21 and PPARγ, and the induction of a less proliferative but more differentiated myofibroblast phenotype. NNMT confers an apoptosis-resistant phenotype to myofibroblasts that is associated with the downregulation of pro-apoptotic members of the Bcl-2 family, including Bim and PUMA. Together, these studies indicate a critical role for NNMT in the metabolic reprogramming of fibroblasts to a pro-fibrotic and apoptosis-resistant phenotype and support the concept that targeting this enzyme may promote regenerative responses in chronic fibrotic disorders such as IPF.


Assuntos
Miofibroblastos , Nicotinamida N-Metiltransferase , Humanos , Apoptose , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Fibroblastos/metabolismo , Fibrose , Fibrose Pulmonar Idiopática/metabolismo , Pulmão/metabolismo , Miofibroblastos/metabolismo , Nicotinamida N-Metiltransferase/metabolismo , Fator de Crescimento Transformador beta1/metabolismo
13.
J Med Chem ; 66(15): 10510-10527, 2023 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-37523719

RESUMO

Nicotinamide N-methyltransferase (NNMT) is a metabolic enzyme implicated in multiple diseases, making it a promising therapeutic target. Building upon our recently reported NNMT inhibitor II399, we systematically investigate the structure-activity relationship by designing and synthesizing a series of analogues. Among them, two top inhibitors II559 (Ki = 1.2 nM) and II802 (Ki = 1.6 nM) displayed over 5000-fold selectivity for NNMT over closely related methyltransferases. Moreover, II559 and II802 showed enhanced cellular inhibition, with a cellular IC50 value of approximately 150 nM, making them the most cell-potent bisubstrate inhibitors reported to date. Furthermore, both inhibitors reduced the cell viability with a GI50 value of ∼10 µM and suppressed the migration of aggressive clear cell renal cancer cell carcinoma cell lines. Overall, II559 and II802 would serve as valuable probes to investigate the enzymatic function of NNMT in health and diseases.


Assuntos
Neoplasias Renais , Nicotinamida N-Metiltransferase , Humanos , Inibidores Enzimáticos/farmacologia , Metiltransferases/metabolismo , Relação Estrutura-Atividade
14.
EMBO J ; 42(13): e112559, 2023 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-37259596

RESUMO

Metastatic colonization of distant organs accounts for over 90% of deaths related to solid cancers, yet the molecular determinants of metastasis remain poorly understood. Here, we unveil a mechanism of colonization in the aggressive basal-like subtype of breast cancer that is driven by the NAD+ metabolic enzyme nicotinamide N-methyltransferase (NNMT). We demonstrate that NNMT imprints a basal genetic program into cancer cells, enhancing their plasticity. In line, NNMT expression is associated with poor clinical outcomes in patients with breast cancer. Accordingly, ablation of NNMT dramatically suppresses metastasis formation in pre-clinical mouse models. Mechanistically, NNMT depletion results in a methyl overflow that increases histone H3K9 trimethylation (H3K9me3) and DNA methylation at the promoters of PR/SET Domain-5 (PRDM5) and extracellular matrix-related genes. PRDM5 emerged in this study as a pro-metastatic gene acting via induction of cancer-cell intrinsic transcription of collagens. Depletion of PRDM5 in tumor cells decreases COL1A1 deposition and impairs metastatic colonization of the lungs. These findings reveal a critical activity of the NNMT-PRDM5-COL1A1 axis for cancer cell plasticity and metastasis in basal-like breast cancer.


Assuntos
Neoplasias , Nicotinamida N-Metiltransferase , Animais , Camundongos , Nicotinamida N-Metiltransferase/genética , Nicotinamida N-Metiltransferase/metabolismo , Neoplasias/metabolismo , Metilação de DNA , Epigênese Genética
15.
Epigenomics ; 15(6): 385-395, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-37212051

RESUMO

Nicotinamide metabolism is important in carcinogenesis. Nicotinamide affects the cellular methyl pool, thus affecting DNA and histone methylation and gene expression. Cancer cells have increased expression of nicotinamide N-methyl transferase (NNMT), the key enzyme in nicotinamide metabolism. NNMT contributes to tumor angiogenesis. Overexpression of NNMT is associated with poorer prognosis in cancers. Additionally, NNMT can contribute to cancer-associated morbidities, such as cancer-associated thrombosis. 1-methylnicotinamide (1-MNA), a metabolite of nicotinamide, has anti-inflammatory and antithrombotic effects. Therefore, targeting NNMT can affect both carcinogenesis and cancer-associated morbidities. Several antitumor drugs have been shown to inhibit NNMT expression in cancer cells. Implementing these drugs to reverse NNMT effects in addition to 1-MNA supplementation has the potential to prevent cancer-associated thrombosis through various mechanisms.


Assuntos
Antineoplásicos , Neoplasias , Humanos , Neoplasias/complicações , Neoplasias/tratamento farmacológico , Neoplasias/genética , Antineoplásicos/farmacologia , Carcinogênese , Niacinamida/farmacologia , Niacinamida/uso terapêutico , Transferases , Nicotinamida N-Metiltransferase/genética , Nicotinamida N-Metiltransferase/metabolismo
16.
Am J Physiol Cell Physiol ; 325(1): C29-C41, 2023 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-37212549

RESUMO

Peroxisome proliferator-activated receptor γ (PPARγ) plays a pivotal role in regulating lipid metabolism and hepatic PPARγ transactivation contributes to fatty liver development. Fatty acids (FAs) are well-known endogenous ligands for PPARγ. Palmitate, a 16-C saturated FA (SFA) and the most abundant SFA in human circulation, is a strong inducer of hepatic lipotoxicity, a central pathogenic factor for various fatty liver diseases. In this study, using both alpha mouse liver 12 (AML12) and primary mouse hepatocytes, we investigated the effects of palmitate on hepatic PPARγ transactivation and underlying mechanisms, as well as the role of PPARγ transactivation in palmitate-induced hepatic lipotoxicity, all of which remain ambiguous currently. Our data revealed that palmitate exposure was concomitant with both PPARγ transactivation and upregulation of nicotinamide N-methyltransferase (NNMT), a methyltransferase catalyzing the degradation of nicotinamide, the predominant precursor for cellular NAD+ biosynthesis. Importantly, we discovered that PPARγ transactivation by palmitate was blunted by NNMT inhibition, suggesting that NNMT upregulation plays a mechanistic role in PPARγ transactivation. Further investigations uncovered that palmitate exposure is associated with intracellular NAD+ decline and NAD+ replenishment with NAD+-enhancing agents, nicotinamide and nicotinamide riboside, obstructed palmitate-induced PPARγ transactivation, implying that cellular NAD+ decline resulted from NNMT upregulation represents a potential mechanism behind palmitate-elicited PPARγ transactivation. At last, our data showed that the PPARγ transactivation marginally ameliorated palmitate-induced intracellular triacylglycerol accumulation and cell death. Collectively, our data provided the first-line evidence supporting that NNMT upregulation plays a mechanistic role in palmitate-elicited PPARγ transactivation, potentially through reducing cellular NAD+ contents.NEW & NOTEWORTHY Hepatic PPARγ transactivation contributes to fatty liver development. Saturated fatty acids (SFAs) induce hepatic lipotoxicity. Here, we investigated whether and how palmitate, the most abundant SFA in the human blood, affects PPARγ transactivation in hepatocytes. We reported for the first time that upregulation of nicotinamide N-methyltransferase (NNMT), a methyltransferase catalyzing the degradation of nicotinamide, the predominant precursor for cellular NAD+ biosynthesis, plays a mechanistic role in regulating palmitate-elicited PPARγ transactivation through reducing intracellular NAD+ contents.


Assuntos
Fígado Gorduroso , Palmitatos , Camundongos , Animais , Humanos , Palmitatos/toxicidade , Nicotinamida N-Metiltransferase/genética , Nicotinamida N-Metiltransferase/metabolismo , Regulação para Cima , NAD/metabolismo , Ativação Transcricional , PPAR gama/genética , PPAR gama/metabolismo , Hepatócitos/metabolismo , Niacinamida/metabolismo , Niacinamida/farmacologia , Ácidos Graxos/metabolismo
17.
Sci Rep ; 13(1): 8293, 2023 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-37217546

RESUMO

Obesity is associated with adipose tissue dysfunction through the differentiation and expansion of pre-adipocytes to adipocytes (hyperplasia) and/or increases in size of pre-existing adipocytes (hypertrophy). A cascade of transcriptional events coordinates the differentiation of pre-adipocytes into fully differentiated adipocytes; the process of adipogenesis. Although nicotinamide N-methyltransferase (NNMT) has been associated with obesity, how NNMT is regulated during adipogenesis, and the underlying regulatory mechanisms, remain undefined. In present study we used genetic and pharmacological approaches to elucidate the molecular signals driving NNMT activation and its role during adipogenesis. Firstly, we demonstrated that during the early phase of adipocyte differentiation NNMT is transactivated by CCAAT/Enhancer Binding Protein beta (CEBPB) in response to glucocorticoid (GC) induction. We found that Nnmt knockout, using CRISPR/Cas9 approach, impaired terminal adipogenesis by influencing the timing of cellular commitment and cell cycle exit during mitotic clonal expansion, as demonstrated by cell cycle analysis and RNA sequencing experiments. Biochemical and computational methods showed that a novel small molecule, called CC-410, stably binds to and highly specifically inhibits NNMT. CC-410 was, therefore, used to modulate protein activity during pre-adipocyte differentiation stages, demonstrating that, in line with the genetic approach, chemical inhibition of NNMT at the early stages of adipogenesis impairs terminal differentiation by deregulating the GC network. These congruent results conclusively demonstrate that NNMT is a key component of the GC-CEBP axis during the early stages of adipogenesis and could be a potential therapeutic target for both early-onset obesity and glucocorticoid-induced obesity.


Assuntos
Adipogenia , Nicotinamida N-Metiltransferase , Camundongos , Animais , Adipogenia/genética , Nicotinamida N-Metiltransferase/metabolismo , Glucocorticoides/uso terapêutico , Diferenciação Celular , Transdução de Sinais , Obesidade/genética , Obesidade/tratamento farmacológico , Células 3T3-L1 , PPAR gama/metabolismo
18.
J Biomol Struct Dyn ; 41(24): 14638-14650, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36856058

RESUMO

Human nicotinamide N-methyltransferase (hNNMT) is a cytosolic enzyme associated in the phase-II metabolism, belonging to the S-adenosyl-L-methionine (SAM)-dependent methyltransferases family. Overexpression of hNNMT was observed in diseases such as metabolic disorders and different types of cancers, which suggest NNMT as a prospective therapeutic target. In this study we propose a structure-based pharmacophore model to understand the structural features responsible for the pharmacological activity. The generated model was validated using the ROC curve (AUC), goodness of hit score (GH), specificity, sensitivity and enrichment factor (EF). The pharmacophore was employed to retrieve active molecules from the ZINC database, followed by virtual-screening and molecular docking. Six molecules with the best pharmfit score, binding energy and ADMET properties were identified in this study. A 150 ns molecular dynamics simulation was performed on the selected molecules complexed with hNNMT protein to validate the results. The molecules ZINC35464499, ZINC13311192, ZINC31159282, ZINC14650833, ZINC14819515 and ZINC00303881 were identified, which could be act as the potential hNNMT inhibitors and can also be used as direct hits for developing novel hNNMT antagonists.Communicated by Ramaswamy H. Sarma.


Assuntos
Simulação de Dinâmica Molecular , Farmacóforo , Humanos , Simulação de Acoplamento Molecular , Nicotinamida N-Metiltransferase , Relação Quantitativa Estrutura-Atividade , Ligantes
19.
Gut ; 73(1): 63-77, 2023 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-36977555

RESUMO

OBJECTIVE: Early gastric cardia adenocarcinoma (EGCA) is a highly heterogeneous cancer, and the understanding of its classification and malignant progression is limited. This study explored the cellular and molecular heterogeneity in EGCA using single-cell RNA sequencing (scRNA-seq). DESIGN: scRNA-seq was conducted on 95 551 cells from endoscopic biopsies of low-grade intraepithelial neoplasia, well/moderately/poorly differentiated EGCA and their paired adjacent nonmalignant biopsy samples. Large-scale clinical samples and functional experiments were employed. RESULTS: Integrative analysis of epithelial cells revealed that chief cells, parietal cells and enteroendocrine cells were rarely detected in the malignant epithelial subpopulation, whereas gland and pit mucous cells and AQP5+ stem cells were predominant during malignant progression. Pseudotime and functional enrichment analyses showed that the WNT and NF-κB signalling pathways were activated during the transition. Cluster analysis of heterogeneous malignant cells revealed that NNMT-mediated nicotinamide metabolism was enriched in gastric mucin phenotype cell population, which was associated with tumour initiation and inflammation-induced angiogenesis. Furthermore, the expression level of NNMT was gradually increased during the malignant progression and associated with poor prognosis in cardia adenocarcinoma. Mechanistically, NNMT catalysed the conversion of nicotinamide to 1-methyl nicotinamide via depleting S-adenosyl methionine, which led to a reduction in H3K27 trimethylation (H3K27me3) and then activated the WNT signalling pathway to maintain the stemness of AQP5+ stem cells during EGCA malignant progression. CONCLUSION: Our study extends the understanding of the heterogeneity of EGCA and identifies a functional NNMT+/AQP5+ population that may drive malignant progression in EGCA and could be used for early diagnosis and therapy.


Assuntos
Adenocarcinoma , Neoplasias Gástricas , Humanos , Cárdia/metabolismo , S-Adenosilmetionina , Células-Tronco Neoplásicas/metabolismo , Niacinamida , Nicotinamida N-Metiltransferase/genética , Nicotinamida N-Metiltransferase/metabolismo , Aquaporina 5
20.
J Exp Clin Cancer Res ; 42(1): 42, 2023 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-36750850

RESUMO

BACKGROUND: Clear cell renal cell carcinoma (ccRCC), with its hallmark phenotype of high cytosolic lipid content, is considered a metabolic cancer. Despite the implication of this lipid-rich phenotype in ccRCC tumorigenesis, the roles and regulators of de novo lipid synthesis (DNL) in ccRCC remain largely unexplained. METHODS: Our bioinformatic screening focused on ccRCC-lipid phenotypes identified glutathione peroxidase 8 (GPX8), as a clinically relevant upstream regulator of DNL. GPX8 genetic silencing was performed with CRISPR-Cas9 or shRNA in ccRCC cell lines to dissect its roles. Untargeted metabolomics, RNA-seq analyses, and other biochemical assays (e.g., lipid droplets staining, fatty acid uptake, cell proliferation, xenograft, etc.) were carried out to investigate the GPX8's involvement in lipid metabolism and tumorigenesis in ccRCC. The lipid metabolic function of GPX8 and its downstream were also measured by isotope-tracing-based DNL flux measurement. RESULTS: GPX8 knockout or downregulation substantially reduced lipid droplet levels (independent of lipid uptake), fatty acid de novo synthesis, triglyceride esterification in vitro, and tumor growth in vivo. The downstream regulator was identified as nicotinamide N-methyltransferase (NNMT): its knockdown phenocopied, and its expression rescued, GPX8 silencing both in vitro and in vivo. Mechanically, GPX8 regulated NNMT via IL6-STAT3 signaling, and blocking this axis suppressed ccRCC survival by activating AMPK. Notably, neither the GPX8-NNMT axis nor the DNL flux was affected by the von Hippel Lindau (VHL) status, the conventional regulator of ccRCC high lipid content. CONCLUSIONS: Taken together, our findings unravel the roles of the VHL-independent GPX8-NNMT axis in ccRCC lipid metabolism as related to the phenotypes and growth of ccRCC, which may be targeted for therapeutic purposes.


Assuntos
Carcinoma de Células Renais , Carcinoma , Neoplasias Renais , Humanos , Carcinoma de Células Renais/patologia , Lipogênese , Transformação Celular Neoplásica/genética , Carcinogênese/genética , Carcinoma/genética , Neoplasias Renais/patologia , Lipídeos , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica , Nicotinamida N-Metiltransferase/genética , Nicotinamida N-Metiltransferase/metabolismo , Peroxidases/genética , Peroxidases/metabolismo
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