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Objectives: This study investigates the role of Nicotinamide N-methyltransferase (NNMT) in immune infiltration modulation through amino acid metabolism in gastric adenocarcinoma (STAD). Methods: Utilizing data from The Cancer Genome Atlas (TCGA) and validated with clinical samples, we analyzed NNMT expression and its prognostic implications in STAD. Differential amino acid profiles between cancerous and adjacent normal tissues were assessed, along with their associations with NNMT. Results: NNMT exhibits heightened expression in STAD cancer tissues, positively correlating with tumor immune infiltration. Additionally, twenty-eight amino acids display differential expression in gastric tissue, with their metabolic enzymes showing connections to NNMT. Conclusions: Elevated NNMT expression in STAD tissues potentially influences amino acid metabolism, thereby affecting immune infiltration dynamics and tumorigenesis in gastric adenocarcinoma.
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Adenocarcinoma , Aminoácidos , Nicotinamida N-Metiltransferase , Neoplasias Gástricas , Nicotinamida N-Metiltransferase/metabolismo , Nicotinamida N-Metiltransferase/genética , Humanos , Neoplasias Gástricas/imunologia , Neoplasias Gástricas/patologia , Neoplasias Gástricas/genética , Neoplasias Gástricas/metabolismo , Adenocarcinoma/genética , Adenocarcinoma/patologia , Adenocarcinoma/imunologia , Adenocarcinoma/metabolismo , Aminoácidos/metabolismo , Prognóstico , Masculino , Feminino , Regulação Neoplásica da Expressão Gênica , Pessoa de Meia-IdadeRESUMO
Microglia, the resident immune cells of the central nervous system (CNS), play a dual role in neurotoxicity by releasing the NLR Family Pyrin Domain Containing 3 (NLRP3) inflammasome and brain-derived neurotrophic factor (BDNF) in response to environmental stress. Suppression of BDNF is implicated in learning and memory impairment induced by exposure to manganese (Mn) or lead (Pb) individually. Methyl CpG Binding Protein 2 (MeCp2) and its phosphorylation status are related to BDNF suppression. Protein phosphatase2A (PP2A), a member of the serine/threonine phosphatases family, dephosphorylates substrates based on the methylation state of its catalytic C subunit (PP2Ac). However, the specific impairment patterns and molecular mechanisms resulting from co-exposure to Mn and Pb remain unclear. Therefore, the purpose of this study was to explore the effects of Mn and Pb exposure, alone and in combination, on inducing neurotoxicity in the hippocampus of mice and BV2 cells, and to determine whether simultaneous exposure to both metals exacerbate their toxicity. Our findings reveal that co-exposure to Mn and Pb leads to severe learning and memory impairment in mice, which correlates with the accumulation of metals in the hippocampus and synergistic suppression of BDNF. This suppression is accompanied by up-regulation of the epigenetic repressor MeCp2 and its phosphorylation status, as well as demethylation of PP2Ac. Furthermore, inhibition of PP2Ac demethylation using ABL127, an inhibitor for its protein phosphatase methylesterase1 (PME1), or knockdown of MeCp2 via siRNA transfection in vitro effectively increases BDNF expression and mitigates BV2 cell damage induced by Mn and Pb co-exposure. We also observe abnormal activation of microglia characterized by enhanced release of the NLRP3 inflammasome, Casepase-1 and pro-inflammatory cytokines IL-1ß, in the hippocampus of mice and BV2 cells. In summary, our experiments demonstrate that simultaneous exposure to Mn and Pb results in more severe hippocampus-dependent learning and memory impairment, which is attributed to epigenetic suppression of BDNF mediated by PP2A regulation.
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Fator Neurotrófico Derivado do Encéfalo , Epigênese Genética , Hipocampo , Chumbo , Manganês , Transtornos da Memória , Animais , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Camundongos , Epigênese Genética/efeitos dos fármacos , Manganês/toxicidade , Chumbo/toxicidade , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Transtornos da Memória/induzido quimicamente , Masculino , Camundongos Endogâmicos C57BL , Microglia/efeitos dos fármacos , Proteína 2 de Ligação a Metil-CpG/metabolismo , Proteína 2 de Ligação a Metil-CpG/genética , Proteína Fosfatase 2/metabolismo , Aprendizagem/efeitos dos fármacosRESUMO
BACKGROUND: UK-5099 is a potent mitochondrial acetone carrier inhibitor, that exhibits anticancer activity. Recently, the anti-Toxoplasma gondii activity of UK-5099 was proposed, and in vivo studies of its pharmacokinetics in BALB/c mice are necessary to further evaluate the clinical effect of UK-5099. METHODS AND RESULTS: A simple and fast high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) analysis method was established and verified in terms of its linearity, matrix effect, accuracy, precision, recovery and stability. The analytes were separated by an Agilent ZORBAX XDB-C18 column (2.1 × 50 mm, 3.5 µm) at 30 °C. A gradient mobile phase consisting of water with 0.1% formic acid (FA) (phase A) and acetonitrile (ACN) (phase B) was delivered at a flow rate of 0.40 mL·min-1 with an injection volume of 5 µL. A good linear response was obtained in a concentration range of 5-5000 ng·mL-1 (r2 = 0.9947). The lower limit of quantification (LLOQ) was 5 ng·mL-1. The extraction recovery of UK-5099 was greater than 95%. The inter- and intra-day accuracy and precision of the method showed relative standard deviations (RSDs) of less than 15%. This method has been successfully applied to the pharmacokinetic evaluation of UK-5099 in mouse plasma. In health mice, the main pharmacokinetic parameters of UK-5099 after intraperitoneal administration were measured using a noncompartmental model, in which the AUC0-t was 42,103 ± 12,072 ng·h·mL-1 and the MRT0-t was 0.857 ± 0.143 h. The peak concentration (Cmax) was 82,500 ± 20,745 ng·h·mL-1, which occurred at a peak time (Tmax) = 0.250 ± 0.000 h. CONCLUSIONS: A fast and sensitive HPLC-MS/MS method was developed, validated and successfully used for the determination of UK-5099 levels in mice after intraperitoneal administration. This study was the first report of the pharmacokinetic parameters of UK-5099 in mice, which will help to further study the administration of UK-5099 in animals and humans.
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Acrilatos , Espectrometria de Massas em Tandem , Animais , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Líquida de Alta Pressão/veterinária , Cromatografia Líquida/veterinária , Camundongos , Espectrometria de Massas em Tandem/métodos , Espectrometria de Massas em Tandem/veterináriaRESUMO
The aim of the present study was to develop a stable formulation containing standardized pomegranate rind extracts (SPRE) for topical use in the treatment of dermal diseases. Ellagic acid (EA) as the major active constituent of SPRE (not less than 13%) was quantified by HPLC as an indicator for studies on the stability, in vitro drug release, and skin penetration/retention. The formulation prepared with polyethylene glycols (PEG 400 and PEG 4000) containing 5% SPRE has been found to be stable and provide a release rate of 36.6741±5.0072 µg/cm(2)/h that was best fitted to the zero-order kinetic model. EA from SPRE did not penetrate the full-thickness rat skin but the skin retention of EA was determined to be 2.22±0.16 µg/cm(2) with a total recovery of 95.14±5.51%. The results indicated that this 5% SPRE PEG ointment was of satisfactory physicochemical properties and worth further in vivo investigations.
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Fármacos Dermatológicos/metabolismo , Lythraceae , Extratos Vegetais/metabolismo , Absorção Cutânea , Pele/metabolismo , Administração Cutânea , Animais , Química Farmacêutica , Fármacos Dermatológicos/administração & dosagem , Fármacos Dermatológicos/química , Fármacos Dermatológicos/isolamento & purificação , Estabilidade de Medicamentos , Ácido Elágico/metabolismo , Excipientes/química , Frutas , Cinética , Lythraceae/química , Masculino , Permeabilidade , Fitoterapia , Extratos Vegetais/administração & dosagem , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Plantas Medicinais , Polietilenoglicóis/química , Ratos Wistar , SolubilidadeRESUMO
The present study evaluated the topical anti-inflammatory potential of a standardized pomegranate rind extracts (SPRE) in parallel with its marker compound ellagic acid (EA, 13% w/w) against a mouse model of contact dermatitis. In the phenol-induced mouse ear edema, topical application of SPRE (5, 2.5, and 1 mg/ear) and EA (0.65, 0.325, and 0.13 mg/ear, equivalent to its content in SPRE) dose-dependently reduced the ear edema with the maximal inhibition of 79.12% and 73.63%, respectively. Triamcinolone (0.1 mg/ear) and diclofenac (1 mg/ear) as reference drugs inhibited the edema by 73.63% and 37.91%. Myeloperoxidase (MPO) activity in the mouse ear was also decreased by SPRE and EA up to 69.68% and 68.79%, respectively. Triamcinolone and diclofenac decreased the MPO activity by 76.66% and 80.14% similarly. The results indicated that topical application of SPRE and EA is promising for use in the treatment of inflammatory skin disorders.
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Anti-Inflamatórios/farmacologia , Dermatite de Contato/tratamento farmacológico , Ácido Elágico/farmacologia , Lythraceae/química , Extratos Vegetais/farmacologia , Animais , Modelos Animais de Doenças , Edema/induzido quimicamente , Edema/tratamento farmacológico , Frutas/química , Masculino , Camundongos , Camundongos Endogâmicos ICR , Peroxidase/metabolismo , Fenóis/efeitos adversosRESUMO
BACKGROUND: Neuropathic pain (NP) is a chronic pathological pain that affects the quality of life and is a huge medical burden for affected patients. In this study, we aimed to explore the effects of secreted phosphoprotein 1 (SPP1) on NP. METHODS: We established a chronic constriction injury (CCI) rat model, knocked down SPP1 via an intrathecal injection, and/or activated the extracellular signal-regulated kinase (ERK) pathway with insulin-like growth factor 1 (IGF-1) treatment. Pain behaviors, including paw withdrawal threshold (PWT), paw withdrawal latency (PWL), lifting number, and frequency, were assessed. After sacrificing rats, the L4-L5 dorsal root ganglion was collected. Then, SPP1 levels were determined using quantitative polymerase chain reaction (qPCR) and western blot analysis. The levels of interleukin (IL)-1ß, tumor necrosis factor (TNF)-α, IL-6, IL-10, epidermal growth factor (EGF), vascular endothelial growth factor (VEGF), and transforming growth factor (TGF)-ß were determined using qPCR and enzyme-linked immunosorbent assay. The levels of ERK pathway factors were determined via western blot analysis. RESULTS: We found that CCI decreased PWT and PWL, increased the lifting number and frequency, and upregulated SPP1 levels. The loss of SPP1 reversed these CCI-induced effects. Additionally, CCI upregulated IL-1ß, TNF-α, IL-6, EGF, and VEGF levels, downregulated TGF-ß levels, and activated the ERK pathway, while silencing of SPP1 abrogated these CCI-induced effects. Moreover, IGF-1 treatment reversed the effects of SPP1 loss. CONCLUSIONS: The data indicate that silencing SPP1 attenuates NP via inactivation of the ERK pathway, suggesting that SPP1 may be a promising target for NP treatment.
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MAP Quinases Reguladas por Sinal Extracelular , Neuralgia , Humanos , Animais , Ratos , Fator A de Crescimento do Endotélio Vascular , Fator de Crescimento Insulin-Like I/genética , Fator de Crescimento Epidérmico , Osteopontina , Interleucina-6 , Qualidade de Vida , Neuralgia/etiologia , Interleucina-1beta , Transdução de Sinais , Nervo IsquiáticoRESUMO
BACKGROUND: Toxoplasmosis is a zoonotic disease caused by the infection of the protozoa Toxoplasma gondii (T. gondii), and safe and effective therapeutic drugs are lacking. Mitochondria, is an important organelle that maintains T. gondii survival, however, drugs targeting mitochondria are lacking. METHODS: The cytotoxicity of BAM15 was detected by CCK-8 and the in vitro effects of BAM15 was detected by qPCR, plaque assay and flow cytometry. Furthermore, the ultrastructural changes of T. gondii after BAM15 treatment were observed by transmission electron microscopy, and further the mitochondrial membrane potential (ΔΨm), ATP level and reactive oxygen species (ROS) of T. gondii after BAM15 treatment were detected. The pharmacokinetic experiments and in vivo infection assays were performed in mice to determine the in vivo effect of BAM15. RESULTS: BAM15 had excellent anti-T. gondii activity in vitro and in vivo with an EC50 value of 1.25 µM, while the IC50 of BAM15 in Vero cells was 27.07 µM. Notably, BAM15 significantly inhibited proliferation activity of T. gondii RH strain and Prugniaud strain (PRU), caused T. gondii death. Furthermore, BAM15 treatment induced T. gondii mitochondrial vacuolation and autolysis by TEM. Moreover, the decrease in ΔΨm and ATP level, as well as the increase in ROS production further confirmed the changes CONCLUSIONS: Our study identifies a useful T. gondii mitochondrial inhibitor, which may also serve as a leading molecule to develop therapeutic mitochondrial inhibitors in toxoplasmosis.'
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Doenças dos Roedores , Toxoplasma , Toxoplasmose , Chlorocebus aethiops , Animais , Camundongos , Células Vero , Espécies Reativas de Oxigênio , Toxoplasmose/tratamento farmacológico , Mitocôndrias , Trifosfato de Adenosina/farmacologia , Trifosfato de Adenosina/uso terapêuticoRESUMO
Interleukin 2 (IL-2) is the first identified cytokine and its interaction with receptors has been known to shape the immune responses in many lymphoid or non-lymphoid tissues for more than four decades. Active T cells are the primary cellular source for IL-2 production and epithelial cells have never been considered the major cellular source of IL-2 under physiological conditions. It is, however, tempting to speculate that epithelial cells could potentially express IL-2 that regulates the intricate interactions between epithelial cells and lymphocytes. Datamining our recently published single-cell RNAseq in the mouse mammary gland identified IL-2 expression in mammary epithelial cells, which is induced by prolactin via the STAT5 signaling pathway. Furthermore, epithelial IL-2 plays a crucial role in maintaining the physiological functions of natural killer (NK) cells within the mammary glands. IL-2 deletion in the mammary epithelial cells leads to a significant reduction in the number and function of NK cells, which in turn results in defective immunosurveillance, expansion of luminal epithelial cells, and tumor development. Interestingly, T cells in the mammary glands are not changed, indicating the specific regulation of NK cells by epithelial IL-2 production. In agreement, we also found that human epithelial cells express IL-2 and NK cells express the highest level of IL2RB among all the immune cells. Here, we provide the first evidence that epithelial cells produce IL-2, which is critical for maintaining the physiological functions of NK cells in immunosurveillance.
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An effective cancer therapy requires killing cancer cells and targeting the tumor microenvironment (TME). Searching for molecules critical for multiple cell types in the TME, we identified NR4A1 as one such molecule that can maintain the immune suppressive TME. Here, we establish NR4A1 as a valid target for cancer immunotherapy and describe a first-of-its-kind proteolysis-targeting chimera (PROTAC, named NR-V04) against NR4A1. NR-V04 degrades NR4A1 within hours in vitro and exhibits long-lasting NR4A1 degradation in tumors with an excellent safety profile. NR-V04 inhibits and frequently eradicates established tumors. At the mechanistic level, NR-V04 induces the tumor-infiltrating (TI) B cells and effector memory CD8+ T (Tem) cells and reduces monocytic myeloid-derived suppressor cells (m-MDSC), all of which are known to be clinically relevant immune cell populations in human melanomas. Overall, NR-V04-mediated NR4A1 degradation holds promise for enhancing anticancer immune responses and offers a new avenue for treating various types of cancers such as melanoma.
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Melanoma , Células Supressoras Mieloides , Humanos , Linhagem Celular Tumoral , Imunoterapia , Melanoma/patologia , Células Supressoras Mieloides/patologia , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/metabolismo , Microambiente Tumoral , Quimera de Direcionamento de ProteóliseRESUMO
Here, we investigated the effects of frying process on the formation of advanced glycation end products (AGEs) in shrimps using Penaeus vannamei as the raw material. The results showed that the oil, malondialdehyde, fluorescent AGEs, carboxymethyl lysine (CML), methylglyoxal hydroimidazolone (MG-H1) and the outer layer carboxyethyl lysine (CEL) content was higher in the fried shrimps than that in the raw unfried shrimps. The outer layer CML, CEL and inner CEL, MG-H1 values all reached the maximum after the first batch of frying (22.43 mg/kg, 304.24 mg/kg, 83.76 mg/kg, and 169.42 mg/kg respectively). However, fluorescent AGEs and MG-H1 of the outer layer reached the maximum after the fifth and fourth batches of frying (1230.0 AU/g and 341.63 mg/kg). Malondialdehyde, fluorescent AGEs, CML, MG-H1, and CEL concentration in the fried shrimps firstly increased and then decreased to stabilization with more frying batches, with higher content in the outer layer of fried shrimps.
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Toxoplasmosis is a widespread disease in humans and animals. Currently, toxoplasmosis chemotherapy options are limited due to severe side effects. There is an urgent need to develop new drugs with better efficacy and few side effects. HQNO, a cytochrome bc1 and type II NADH inhibitor in eukaryotes and bacteria, possesses extensive bioactivity. In this study, the cytotoxicity of HQNO was evaluated in Vero cells. The in vitro effects of HQNO were determined by plaque assay and qPCR assay. To determine the in vivo effect of HQNO, pharmacokinetic experiments and in vivo infection assays were performed in mice. The changes in tachyzoites after HQNO exposure were examined by transmission electron microscopy (TEM), MitoTracker Red CMXRos staining, ROS detection and ATP detection. HQNO inhibited T. gondii invasion and proliferation with an EC50 of 0.995 µM. Pharmacokinetic experiments showed that the Cmax of HQNO (20 mg/kg·bw) was 3560 ± 1601 ng/mL (13.73 µM) in healthy BALB/c mouse plasma with no toxicity in vivo. Moreover, HQNO induced a significant decrease in the parasite burden load of T. gondii in mouse peritoneum. TEM revealed alterations in the mitochondria of T. gondii. Further assays verified that HQNO also decreased the mitochondrial membrane potential (ΔΨm) and ATP levels and enhanced the level of reactive oxygen species (ROS) in T. gondii. Hence, HQNO exerted anti-T. gondii activity, which may be related to the damage to the mitochondrial electron transport chain (ETC).
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Toxoplasma , Toxoplasmose , Humanos , Chlorocebus aethiops , Animais , Camundongos , Toxoplasma/genética , Células Vero , Espécies Reativas de Oxigênio/metabolismo , Toxoplasmose/tratamento farmacológico , Trifosfato de Adenosina/metabolismoRESUMO
The mismatch repair (MMR) pathway is known as a tumor suppressive pathway and genes involved in MMR are commonly mutated in hereditary colorectal or other cancer types. However, the function of MMR genes/proteins in breast cancer progression and metastasis are largely unknown. We found that MSH2, but not MLH1, is highly enriched in basal-like breast cancer (BLBC) and that its protein expression is inversely correlated with overall survival time (OS). MSH2 expression is frequently elevated due to genomic amplification or gain-of-expression in BLBC, which results in increased MSH2 protein to pair with MSH6 (collectively referred to as MutSα). Genetic deletion of MSH2 or MLH1 results in a contrasting phenotype in metastasis, with MSH2-deletion leading to reduced metastasis and MLH1-deletion to enhanced liver or lung metastasis. Mechanistically, MSH2-deletion induces the expression of a panel of chemokines in BLBC via epigenetic and/or transcriptional regulation, which leads to an immune reactive tumor microenvironment (TME) and elevated immune cell infiltrations. MLH1 is not correlated with chemokine expression and/or immune cell infiltration in BLBC, but its deletion results in strong accumulation of neutrophils that are known for metastasis promotion. Our study supports the differential functions of MSH2 and MLH1 in BLBC progression and metastasis, which challenges the paradigm of the MMR pathway as a universal tumor suppressive mechanism.
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An effective cancer therapy requires both killing cancer cells and targeting tumor-promoting pathways or cell populations within the tumor microenvironment (TME). We purposely search for molecules that are critical for multiple tumor-promoting cell types and identified nuclear receptor subfamily 4 group A member 1 (NR4A1) as one such molecule. NR4A1 has been shown to promote the aggressiveness of cancer cells and maintain the immune suppressive TME. Using genetic and pharmacological approaches, we establish NR4A1 as a valid therapeutic target for cancer therapy. Importantly, we have developed the first-of-its kind proteolysis-targeting chimera (PROTAC, named NR-V04) against NR4A1. NR-V04 effectively degrades NR4A1 within hours of treatment in vitro and sustains for at least 4 days in vivo, exhibiting long-lasting NR4A1-degradation in tumors and an excellent safety profile. NR-V04 leads to robust tumor inhibition and sometimes eradication of established melanoma tumors. At the mechanistic level, we have identified an unexpected novel mechanism via significant induction of tumor-infiltrating (TI) B cells as well as an inhibition of monocytic myeloid derived suppressor cells (m-MDSC), two clinically relevant immune cell populations in human melanomas. Overall, NR-V04-mediated NR4A1 degradation holds promise for enhancing anti-cancer immune responses and offers a new avenue for treating various types of cancer.
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BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most malignant type of cancers. Leuci carboxyl methyltransferase 1 (LCMT1) is a protein methyltransferase that plays an improtant regulatory role in both normal and cancer cells. The aim of this study is to evaluate the expression pattern and clinical significance of LCMT1 in HCC. METHODS: The expression pattern and clinical relevance of LCMT1 were determined using the Gene Expression Omnibus (GEO) database, the Cancer Genome Atlas (TCGA) program, and our datasets. Gain-of-function and loss-of-function studies were employed to investigate the cellular functions of LCMT1 in vitro and in vivo. Quantitative real-time polymerase chain reaction (RT-PCR) analysis, western blotting, enzymatic assay, and high-performance liquid chromatography were applied to reveal the underlying molecular functions of LCMT1. RESULTS: LCMT1 was upregulated in human HCC tissues, which correlated with a "poor" prognosis. The siRNA-mediated knockdown of LCMT1 inhibited glycolysis, promoted mitochondrial dysfunction, and increased intracellular pyruvate levels by upregulating the expression of alani-neglyoxylate and serine-pyruvate aminotransferase (AGXT). The overexpression of LCMT1 showed the opposite results. Silencing LCMT1 inhibited the proliferation of HCC cells in vitro and reduced the growth of tumor xenografts in mice. Mechanistically, the effect of LCMT1 on the proliferation of HCC cells was partially dependent on PP2A. CONCLUSIONS: Our data revealed a novel role of LCMT1 in the proliferation of HCC cells. In addition, we provided novel insights into the effects of glycolysis-related pathways on the LCMT1regulated progression of HCC, suggesting LCMT1 as a novel therapeutic target for HCC therapy.
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Impaired glucose regulation is one of the most important risk factors for type 2 diabetes mellitus (T2DM) and cardiovascular diseases, which have become a major public health issue worldwide. Dysregulation of carbohydrate metabolism in liver has been shown to play a critical role in the development of glucose intolerance but the molecular mechanism has not yet been fully understood. In this study, we investigated the role of hepatic LCMT1 in the regulation of glucose homeostasis using a liver-specific LCMT1 knockout mouse model. The hepatocyte-specific deletion of LCMT1 significantly upregulated the hepatic glycogen synthesis and glycogen accumulation in liver. We found that the liver-specific knockout of LCMT1 improved high fat diet-induced glucose intolerance and insulin resistance. Consistently, the high fat diet-induced downregulation of glucokinase (GCK) and other important glycogen synthesis genes were reversed in LCMT1 knockout liver. In addition, the expression of GCK was significantly upregulated in MIHA cells treated with siRNA targeting LCMT1 and improved glycogen synthesis. In this study, we provided evidences to support the role of hepatic LCMT1 in the development of glucose intolerance induced by high fat diet and demonstrated that inhibiting LCMT1 could be a novel therapeutic strategy for the treatment of glucose metabolism disorders.
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Diabetes Mellitus Tipo 2 , Intolerância à Glucose , Resistência à Insulina , Proteína O-Metiltransferase , Camundongos , Animais , Intolerância à Glucose/etiologia , Intolerância à Glucose/metabolismo , Dieta Hiperlipídica/efeitos adversos , Leucina/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Fígado/metabolismo , Glucose/metabolismo , Glicogênio/metabolismo , Metiltransferases/metabolismo , Proteína O-Metiltransferase/metabolismoRESUMO
Non-alcoholic fatty liver disease (NAFLD) is a progressive disorder of liver metabolism and has become the most common chronic liver disease worldwide. Benzo[a]pyrene (BaP) is recognized as a potent carcinogen, but the effect of low-dose BaP on the development of NAFLD has not been well-studied, and its molecular mechanism is still unknown. In this study, we demonstrated that low-dose BaP induced hepatic steatosis in a mouse model with a notable increase in hepatic lipid content. Interestingly, mRNA expression of genes related to fatty acids uptake or synthesis was not significantly altered after BaP exposure. Instead, we found that low-dose BaP promoted lipid deposition in primary mouse hepatocytes by inhibiting autophagy, which was regulated through Leucine carboxyl methyltransferase-1 (LCMT1) mediated Protein Phosphatases 2A subunit C (PP2Ac) methylation. The role of LCMT1 in BaP-induced steatosis was further validated in a liver-specific lcmt1 knockout (L-LCMT1 KO) mouse model. In this study, we provided evidence to support a novel mechanism by which BaP induces the development of hepatic steatosis through PP2Ac mediated autophagy inhibition. These findings provided new insight into the pathogenesis of NAFLD induced by environmental exposure to low-dose BaP.
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Hepatopatia Gordurosa não Alcoólica , Animais , Camundongos , Hepatopatia Gordurosa não Alcoólica/metabolismo , Benzo(a)pireno/metabolismo , Fígado , Fosfoproteínas Fosfatases , Autofagia , LipídeosRESUMO
The oncogenic role of estrogen receptor (ER) signaling in breast cancer has long been established. Interaction of estrogen with estrogen receptor (ER) in the nucleus activates genomic pathways of estrogen signaling. In contrast, estrogen interaction with the cell membrane-bound G-protein-coupled estrogen receptor (GPER) activates the rapid receptor-mediated signaling transduction cascades. Aberrant estrogen signaling enhances mammary epithelial cell proliferation, survival, and angiogenesis, hence is an important step towards breast cancer initiation and progression. Meanwhile, a growing number of studies also provide evidence for estrogen's pro- or anti-inflammatory roles. As other articles in this issue cover classic ER and GPER signaling mediated by estrogen, this review will discuss the crucial mechanisms by which estrogen signaling influences chronic inflammation and how that is involved in breast cancer. Xenoestrogens acquired from plant diet or exposure to industrial products constantly interact with and alter innate estrogen signaling at various levels. As such, they can modulate chronic inflammation and breast cancer development. Natural xenoestrogens generally have anti-inflammatory properties, which is consistent with their chemoprotective role in breast cancer. In contrast, synthetic xenoestrogens are proinflammatory and carcinogenic compounds that can increase the risk of breast cancer. This article also highlights important xenoestrogens with a particular focus on their role in inflammation and breast cancer. Improved understanding of the complex relationship between estrogens, inflammation, and breast cancer will guide clinical research on agents that could advance breast cancer prevention and therapy.
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Regulatory T cells (Tregs) play an important role in maintaining immune homeostasis and, within tumors, their upregulation is common and promotes an immunosuppressive microenvironment. Therapeutic strategies that can eliminate Tregs in the tumor (i.e., therapies that do not run the risk of affecting normal tissues), are urgently needed for the development of cancer immunotherapies. Here we report our discovery of B-cell lymphoma extra-large (BCL-XL) as a potential molecular target of tumor-infiltrating (TI) Tregs. We show that pharmacological degradation of BCL-XL using a newly developed platelet-sparing BCL-XL Proteolysis-targeting chimera (PROTAC) induces the apoptosis of TI-Tregs and the activation of TI-CD8+ T cells. Moreover, these activities result in an effective suppression of syngeneic tumor growth in immunocompetent, but not in immunodeficient or CD8+ T cell-depleted mice. Notably, treatment with BCL-XL PROTAC does not cause detectable damage within several normal tissues or thrombocytopenia. These findings identify BCL-XL as a target in the elimination of TI-Tregs as a component of cancer immunotherapies, and that the BCL-XL-specific PROTAC has the potential to be developed as a therapeutic for cancer immunotherapy.
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Linfócitos do Interstício Tumoral/metabolismo , Linfócitos T Reguladores/metabolismo , Animais , Sistemas CRISPR-Cas/genética , Sistemas CRISPR-Cas/fisiologia , Sobrevivência Celular/genética , Sobrevivência Celular/fisiologia , Células Cultivadas , Feminino , Citometria de Fluxo , Immunoblotting , Camundongos , Camundongos Endogâmicos C57BL , Proteólise , Proteína bcl-X/genética , Proteína bcl-X/metabolismoRESUMO
13-Chlorine-3,15-dioxy-gibberellic acid methyl ester (GA-13315) is a gibberellin derivative that exhibits selective cytotoxicity to multidrug resistant MCF-7/ADR cells and reverses drug resistance when administered at subtoxic doses in combination with chemotherapy drugs. The present study aimed to investigate the impact of chronic GA-13315 exposure on the chemosensitivity of MCF-7 and HCT116 cell lines. Cells were administered a subtoxic dose of 1 µM GA-13315 for 12 weeks and the sensitivity of the cells to GA-13315, irinotecan and cisplatin, was assessed. The Cell Counting Kit-8 assay results demonstrated that the chronic exposure did not induce resistance to GA-13315, in either MCF-7 or HCT116 cells. Notably, MCF-7 cells were sensitized to irinotecan following exposure to GA-13315; however, HCT116 cells were not. The sensitizing effect of GA-13315 was associated with the alterations of topoisomerase 1 (Top1) protein expression, tyrosyl DNA phosphodiesterase 1 and checkpoint kinase 1. Further analysis indicated that GA-13315 caused DNA fragmentation; however, DNA damage was not mediated by a Top1-dependent molecular mechanism, as GA-13315 was revealed not to be a Top1 poison, despite inhibiting the catalytic activity of Top1. Taken together, the results of the present study indicated that GA-13315 may be used for sensitizing MCF-7 cells to irinotecan, as the chronic exposure of GA-13315 to MCF-7 cells still showed sensitizing effects to irinotecan.
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Abnormal osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) has been correlated with the pathogenesis of osteoporosis. Geraniin, a polyphenolic compound isolated from Phyllanthus amarus, is effective in preventing osteoporosis, but the mechanisms of action of geraniin and the impact of osteoporotic condition on drug action are not known. In this study we compared the proliferation and osteoblastic differentiation potential of BMSCs from normal rats with that from osteoporotic rats, and examined the responses of both BMSCs to geraniin in parallel. BMSCs of rats subjected to ovariectomy or sham operation were isolated and treated with geraniin. Cell proliferation was measured by CCK-8 assay. Osteoblastic differentiation was quantified by Alizarin Red S staining and alkaline phosphatase assay. Nuclear translocation of ß-catenin was monitored by immunofluorescent staining. Expression of ß-catenin was determined by Western blot and quantitative real-time polymerase chain reaction. Results showed that the proliferation and osteoblast formation of osteoporotic BMSCs decreased in comparison to that of normal BMSCs. Geraniin enhanced proliferation and osteoblastic differentiation of both BMSCs, but the responses of osteoporotic BMSCs to geraniin were less than those of normal BMSCs. Expression and nuclear accumulation of ß-catenin in osteoporotic BMSCs were found to be diminished. Geraniin increased nuclear translocation and expression of ß-catenin in both BMSCs. This study associated the osteogenic effect of geraniin to activation of Wnt/ß-catenin signaling, and provided rationale for pharmacological investigation of geraniin in osteoporosis prevention and treatment.