Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 101
Filtrar
1.
Nutr Cancer ; 76(6): 463-468, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38591931

RESUMO

Methionine is an essential amino acid critical for cell growth and survival. Preclinical evidence suggests a methionine restricted diet (MRD) sensitizes cancer to radiation therapy (RT), without significant adverse effects. However, this has never been evaluated in humans. The purpose of this pilot study was to evaluate the safety and feasibility of concurrent MRD with standard-of-care definitive RT in adults with any non-skin cancer malignancy. The MRD extended from 2 wk before RT initiation, through 2 wk beyond RT completion. The primary endpoint of safety was assessed as rate of grade 3 or higher acute and late toxicities. Feasibility was assessed with quantitative plasma amino acid panel every 2 wk during the MRD (target plasma methionine 13 µM). Nine patients were accrued over a two-year period, with five able to complete the treatment course. The trial was closed due to slow accrual and subjects' difficulty maintaining the diet. No grade 3 or higher adverse events were observed. Subjects' average methionine level was 18.8 µM during treatment, with average nadir 16.8 µM. These findings suggest the safety of concurrent MRD with RT, with toxicities comparable to those expected with RT alone. However, the diet was challenging, and unacceptable to most patients.


Assuntos
Metionina , Humanos , Metionina/sangue , Masculino , Pessoa de Meia-Idade , Feminino , Projetos Piloto , Idoso , Adulto , Neoplasias/radioterapia , Neoplasias/dietoterapia , Dieta
2.
Int J Mol Sci ; 25(2)2024 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-38256089

RESUMO

Astronauts in space are subject to continuous exposure to ionizing radiation. There is concern about the acute and late-occurring adverse health effects that astronauts could incur following a protracted exposure to the space radiation environment. Therefore, it is vital to consider the current tools and models used to describe and study the organic consequences of ionizing radiation exposure. It is equally important to see where these models could be improved. Historically, radiobiological models focused on how radiation damages nuclear deoxyribonucleic acid (DNA) and the role DNA repair mechanisms play in resulting biological effects, building on the hypotheses of Crowther and Lea from the 1940s and 1960s, and they neglected other subcellular targets outside of nuclear DNA. The development of these models and the current state of knowledge about radiation effects impacting astronauts in orbit, as well as how the radiation environment and cellular microenvironment are incorporated into these radiobiological models, aid our understanding of the influence space travel may have on astronaut health. It is vital to consider the current tools and models used to describe the organic consequences of ionizing radiation exposure and identify where they can be further improved.


Assuntos
Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Exposição à Radiação , Lesões por Radiação , Humanos , Astronautas , Microambiente Celular , DNA
3.
Int J Mol Sci ; 22(5)2021 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-33673497

RESUMO

Both cell and animal studies have shown that complete or partial deficiency of methionine inhibits tumor growth. Consequently, the potential implementation of this nutritional intervention has recently been of great interest for the treatment of cancer patients. Unfortunately, diet alteration can also affect healthy immune cells such as monocytes/macrophages and their precursor cells in bone marrow. As around half of cancer patients are treated with radiotherapy, the potential deleterious effect of dietary methionine deficiency on immune cells prior to and/or following irradiation needs to be evaluated. Therefore, we examined whether modulation of methionine content alters genetic stability in the murine RAW 264.7 monocyte/macrophage cell line in vitro by chromosomal analysis after 1-month culture in a methionine-deficient or supplemented medium. We also analyzed chromosomal aberrations in the bone marrow cells of CBA/J mice fed with methionine-deficient or supplemented diet for 2 months. While all RAW 264.7 cells revealed a complex translocation involving three chromosomes, three different clones based on the banding pattern of chromosome 9 were identified. Methionine deficiency altered the ratio of the three clones and increased chromosomal aberrations and DNA damage in RAW 264.7. Methionine deficiency also increased radiation-induced chromosomal aberration and DNA damage in RAW 264.7 cells. Furthermore, mice maintained on a methionine-deficient diet showed more chromosomal aberrations in bone marrow cells than those given methionine-adequate or supplemented diets. These findings suggest that caution is warranted for clinical implementation of methionine-deficient diet concurrent with conventional cancer therapy.


Assuntos
Células da Medula Óssea/metabolismo , Aberrações Cromossômicas , Dano ao DNA , Desnutrição/genética , Metionina/deficiência , Animais , Reparo do DNA , Dieta , Macrófagos , Masculino , Desnutrição/metabolismo , Camundongos , Camundongos Endogâmicos CBA , Monócitos , Células RAW 264.7
4.
Am J Physiol Gastrointest Liver Physiol ; 318(3): G439-G450, 2020 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-31961718

RESUMO

Methionine is an essential amino acid needed for a variety of processes in living organisms. Ionizing radiation depletes tissue methionine concentrations and leads to the loss of DNA methylation and decreased synthesis of glutathione. In this study, we aimed to investigate the effects of methionine dietary supplementation in CBA/CaJ mice after exposure to doses ranging from 3 to 8.5 Gy of 137Cs of total body irradiation. We report that mice fed a methionine-supplemented diet (MSD; 19.5 vs. 6.5 mg/kg in a methionine-adequate diet, MAD) developed acute radiation toxicity at doses as low as 3 Gy. Partial body irradiation performed with hindlimb shielding resulted in a 50% mortality rate in MSD-fed mice exposed to 8.5 Gy, suggesting prevalence of radiation-induced gastrointestinal syndrome in the development of acute radiation toxicity. Analysis of the intestinal microbiome demonstrated shifts in the gut ecology, observed along with the development of leaky gut syndrome and bacterial translocation into the liver. Normal gut physiology impairment was facilitated by alterations in the one-carbon metabolism pathway and was exhibited as decreases in circulating citrulline levels mirrored by decreased intestinal mucosal surface area and the number of surviving crypts. In conclusion, we demonstrate that a relevant excess of methionine dietary intake exacerbates the detrimental effects of exposure to ionizing radiation in the small intestine.NEW & NOTEWORTHY Methionine supplementation, instead of an anticipated health-promoting effect, sensitizes mice to gastrointestinal radiation syndrome. Mechanistically, excess of methionine negatively affects intestinal ecology, leading to a cascade of physiological, biochemical, and molecular alterations that impair normal gut response to a clinically relevant genotoxic stressor. These findings speak toward increasing the role of registered dietitians during cancer therapy and the necessity of a solid scientific background behind the sales of dietary supplements and claims regarding their benefits.


Assuntos
Síndrome Aguda da Radiação/etiologia , Suplementos Nutricionais/toxicidade , Intestino Delgado/efeitos dos fármacos , Metionina/toxicidade , Lesões Experimentais por Radiação/etiologia , Síndrome Aguda da Radiação/metabolismo , Síndrome Aguda da Radiação/microbiologia , Síndrome Aguda da Radiação/patologia , Animais , Metilação de DNA/efeitos dos fármacos , Disbiose , Metabolismo Energético/efeitos dos fármacos , Microbioma Gastrointestinal/efeitos dos fármacos , Intestino Delgado/metabolismo , Intestino Delgado/microbiologia , Intestino Delgado/patologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos CBA , Doses de Radiação , Lesões Experimentais por Radiação/metabolismo , Lesões Experimentais por Radiação/microbiologia , Lesões Experimentais por Radiação/patologia , Fatores de Risco , Irradiação Corporal Total
5.
Int J Mol Sci ; 21(20)2020 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-33096940

RESUMO

Cannabidiol (CBD) is a biologically active, non-psychotropic component of Cannabis sativa whose popularity has grown exponentially in recent years. Besides a wealth of potential health benefits, ingestion of CBD poses risks for a number of side effects, of which hepatotoxicity and CBD/herb-drug interactions are of particular concern. Here, we investigated the interaction potential between the cannabidiol-rich cannabis extract (CRCE) and methylsulfonylmethane (MSM), a popular dietary supplement, in the mouse model. For this purpose, 8-week-old male C57BL6/J mice received MSM-containing water (80 mg/100 mL) ad libitum for 17 days. During the last three days of treatment, mice received three doses of CRCE administered in sesame oil via oral gavage (123 mg/kg/day). Administration of MSM alone did not result in any evidence of liver toxicity and did not induce expression of mouse cytochrome P450 (CYP) enzymes. Administration of CRCE did produce significant (p < 0.05) increases in Cyp1a2, Cyp2b10, Cyp2c29, Cyp3a4, Cyp3a11, Cyp2c65, and Cyp2c66 messenger RNA, however, this effect was not amplified by MSM/CRCE co-treatment. Similarly, no evidence of liver toxicity was observed in MSM/CRCE dosed mice. In conclusion, short-term MSM/CRCE co-administration did not demonstrate any evidence of hepatotoxicity in the mouse model.


Assuntos
Canabidiol/toxicidade , Extratos Vegetais/toxicidade , Fosfatase Alcalina/sangue , Animais , Canabidiol/farmacocinética , Cannabis/química , Doença Hepática Induzida por Substâncias e Drogas/sangue , Doença Hepática Induzida por Substâncias e Drogas/patologia , Sistema Enzimático do Citocromo P-450/metabolismo , Suplementos Nutricionais/toxicidade , Glutamina/análogos & derivados , Glutamina/metabolismo , Interações Ervas-Drogas , Masculino , Camundongos Endogâmicos C57BL , Extratos Vegetais/química , Extratos Vegetais/farmacocinética , Taurina/análogos & derivados , Taurina/metabolismo , Testes de Toxicidade
6.
Molecules ; 24(9)2019 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-31052254

RESUMO

The goal of this study was to investigate Cannabidiol (CBD) hepatotoxicity in 8-week-old male B6C3F1 mice. Animals were gavaged with either 0, 246, 738, or 2460 mg/kg of CBD (acute toxicity, 24 h) or with daily doses of 0, 61.5, 184.5, or 615 mg/kg for 10 days (sub-acute toxicity). These doses were the allometrically scaled mouse equivalent doses (MED) of the maximum recommended human maintenance dose of CBD in EPIDIOLEX® (20 mg/kg). In the acute study, significant increases in liver-to-body weight (LBW) ratios, plasma ALT, AST, and total bilirubin were observed for the 2460 mg/kg dose. In the sub-acute study, 75% of mice gavaged with 615 mg/kg developed a moribund condition between days three and four. As in the acute phase, 615 mg/kg CBD increased LBW ratios, ALT, AST, and total bilirubin. Hepatotoxicity gene expression arrays revealed that CBD differentially regulated more than 50 genes, many of which were linked to oxidative stress responses, lipid metabolism pathways and drug metabolizing enzymes. In conclusion, CBD exhibited clear signs of hepatotoxicity, possibly of a cholestatic nature. The involvement of numerous pathways associated with lipid and xenobiotic metabolism raises serious concerns about potential drug interactions as well as the safety of CBD.


Assuntos
Canabidiol/química , Canabidiol/farmacologia , Cannabis/química , Hepatócitos/efeitos dos fármacos , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Animais , Biomarcadores , Doença Hepática Induzida por Substâncias e Drogas/etiologia , Doença Hepática Induzida por Substâncias e Drogas/metabolismo , Doença Hepática Induzida por Substâncias e Drogas/patologia , Modelos Animais de Doenças , Perfilação da Expressão Gênica , Hepatócitos/metabolismo , Testes de Função Hepática , Camundongos , Transcriptoma
7.
Molecules ; 24(12)2019 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-31212965

RESUMO

The goal of this study was to investigate the potential for a cannabidiol-rich cannabis extract (CRCE) to interact with the most common over-the-counter drug and the major known cause of drug-induced liver injury-acetaminophen (APAP)-in aged female CD-1 mice. Gavaging mice with 116 mg/kg of cannabidiol (CBD) [mouse equivalent dose (MED) of 10 mg/kg of CBD] in CRCE delivered with sesame oil for three consecutive days followed by intraperitoneally (i.p.) acetaminophen (APAP) administration (400 mg/kg) on day 4 resulted in overt toxicity with 37.5% mortality. No mortality was observed in mice treated with 290 mg/kg of CBD+APAP (MED of 25 mg/kg of CBD) or APAP alone. Following CRCE/APAP co-administration, microscopic examination revealed a sinusoidal obstruction syndrome-like liver injury-the severity of which correlated with the degree of alterations in physiological and clinical biochemistry end points. Mechanistically, glutathione depletion and oxidative stress were observed between the APAP-only and co-administration groups, but co-administration resulted in much greater activation of c-Jun N-terminal kinase (JNK). Strikingly, these effects were not observed in mice gavaged with 290 mg/kg CBD in CRCE followed by APAP administration. These findings highlight the potential for CBD/drug interactions, and reveal an interesting paradoxical effect of CBD/APAP-induced hepatotoxicity.


Assuntos
Acetaminofen/efeitos adversos , Canabidiol/efeitos adversos , Hepatopatia Veno-Oclusiva/diagnóstico , Hepatopatia Veno-Oclusiva/etiologia , Animais , Biomarcadores , Canabidiol/química , Cannabis/química , Doença Hepática Induzida por Substâncias e Drogas/diagnóstico , Doença Hepática Induzida por Substâncias e Drogas/etiologia , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Feminino , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Camundongos , Camundongos Endogâmicos , Compostos Fitoquímicos/efeitos adversos , Compostos Fitoquímicos/química , Extratos Vegetais/efeitos adversos
8.
Carcinogenesis ; 39(9): 1117-1126, 2018 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-29939201

RESUMO

Methionine dependency describes the characteristic rapid in vitro death of most tumor cells in the absence of methionine. Combining chemotherapy with dietary methionine deprivation [methionine-deficient diet (MDD)] at tolerable levels has vast potential in tumor treatment; however, it is limited by MDD-induced toxicity during extended deprivation. Recent advances in imaging and irradiation delivery have created the field of stereotactic body radiotherapy (SBRT), where fewer large-dose fractions delivered in less time result in increased local-tumor control, which could be maximally synergistic with an MDD short course. Identification of the lowest effective methionine dietary intake not associated with toxicity will further enhance the cancer therapy potential. In this study, we investigated the effects of MDD and methionine-restricted diet (MRD) in primary and metastatic melanoma models in combination with radiotherapy (RT). In vitro, MDD dose-dependently sensitized mouse and human melanoma cell lines to RT. In vivo in mice, MDD substantially potentiated the effects of RT by a significant delay in tumor growth, in comparison with administering MDD or RT alone. The antitumor effects of an MDD/RT approach were due to effects on one-carbon metabolism, resulting in impaired methionine biotransformation via downregulation of Mat2a, which encodes methionine adenosyltransferase 2A. Furthermore, and probably most importantly, MDD and MRD substantially diminished metastatic potential; the antitumor MRD effects were not associated with toxicity to normal tissue. Our findings suggest that modulation of methionine intake holds substantial promise for use with short-course SBRT for cancer treatment.


Assuntos
Antineoplásicos/farmacologia , Melanoma/dietoterapia , Melanoma/patologia , Metionina Adenosiltransferase/biossíntese , Metionina/farmacologia , Animais , Antineoplásicos/administração & dosagem , Linhagem Celular Tumoral , Humanos , Masculino , Metionina/administração & dosagem , Metionina/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Metástase Neoplásica/patologia
9.
Int J Cancer ; 142(5): 874-882, 2018 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-28836271

RESUMO

The interaction between the (epi)genetic makeup of an individual and his/her environmental exposure record (exposome) is accepted as a determinant factor for a significant proportion of human malignancies. Recent evidence has highlighted the key role of epigenetic mechanisms in mediating gene-environment interactions and translating exposures into tumorigenesis. There is also growing evidence that epigenetic changes may be risk factor-specific ("fingerprints") that should prove instrumental in the discovery of new biomarkers in cancer. Here, we review the state of the science of epigenetics associated with environmental stimuli and cancer risk, highlighting key developments in the field. Critical knowledge gaps and research needs are discussed and advances in epigenomics that may help in understanding the functional relevance of epigenetic alterations. Key elements required for causality inferences linking epigenetic changes to exposure and cancer are discussed and how these alterations can be incorporated in carcinogen evaluation and in understanding mechanisms underlying epigenome deregulation by the environment.


Assuntos
Exposição Ambiental/efeitos adversos , Epigênese Genética , Epigenômica , Interação Gene-Ambiente , Neoplasias/etiologia , Animais , Metilação de DNA , Humanos , Neoplasias/patologia , Fatores de Risco
10.
Int J Mol Sci ; 18(7)2017 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-28677663

RESUMO

Long Interspersed Nuclear Element 1 (LINE-1) retrotransposons are the major repetitive elements in mammalian genomes. LINE-1s are well-accepted as driving forces of evolution and critical regulators of the expression of genetic information. Alterations in LINE-1 DNA methylation may lead to its aberrant activity and are reported in virtually all human cancers and in experimental carcinogenesis. In this study, we investigated the endogenous DNA methylation status of the 5' untranslated region (UTR) of LINE-1 elements in the bone marrow hematopoietic stem cells (HSCs), hematopoietic progenitor cells (HPCs), and mononuclear cells (MNCs) in radioresistant C57BL/6J and radiosensitive CBA/J mice and in response to ionizing radiation (IR). We demonstrated that basal levels of DNA methylation within the 5'-UTRs of LINE-1 elements did not differ significantly between the two mouse strains and were negatively correlated with the evolutionary age of LINE-1 elements. Meanwhile, the expression of LINE-1 elements was higher in CBA/J mice. At two months after irradiation to 0.1 or 1 Gy of 137Cs (dose rate 1.21 Gy/min), significant decreases in LINE-1 DNA methylation in HSCs were observed in prone to radiation-induced carcinogenesis CBA/J, but not C57BL/6J mice. At the same time, no residual DNA damage, increased ROS, or changes in the cell cycle were detected in HSCs of CBA/J mice. These results suggest that epigenetic alterations may potentially serve as driving forces of radiation-induced carcinogenesis; however, future studies are needed to demonstrate the direct link between the LINE-1 DNA hypomethylation and radiation carcinogenesis.


Assuntos
Metilação de DNA/efeitos da radiação , Células-Tronco Hematopoéticas/metabolismo , Células-Tronco Hematopoéticas/efeitos da radiação , Elementos Nucleotídeos Longos e Dispersos , Radiação Ionizante , Animais , Dano ao DNA , Relação Dose-Resposta à Radiação , Regulação da Expressão Gênica/efeitos da radiação , Hematopoese/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos CBA , Retroelementos , Especificidade da Espécie
11.
Pharm Res ; 33(9): 2117-25, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27216753

RESUMO

PURPOSE: Ionizing radiation (IR) generates reactive oxygen species (ROS), which cause DNA double-strand breaks (DSBs) that are responsible for cytogenetic alterations. Because antioxidants are potent ROS scavengers, we determined whether the vitamin E isoform γ-tocotrienol (GT3), a radio-protective multifunctional dietary antioxidant, can suppress IR-induced cytogenetic damage. METHODS: We measured DSB formation in irradiated primary human umbilical vein endothelial cells (HUVECs) by quantifying the formation of γ-H2AX foci. Chromosomal aberrations (CAs) were analyzed in irradiated HUVECs and in the bone marrow cells of irradiated mice by conventional and fluorescence-based chromosome painting techniques. Gene expression was measured in HUVECs with quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). RESULTS: GT3 pretreatment reduced DSB formation in HUVECS, and also decreased CAs in HUVECs and mouse bone marrow cells after irradiation. Moreover, GT3 increased expression of the DNA-repair gene RAD50 and attenuated radiation-induced RAD50 suppression. CONCLUSIONS: GT3 attenuates radiation-induced cytogenetic damage, possibly by affecting RAD50 expression. GT3 should be explored as a therapeutic to reduce the risk of developing genetic diseases after radiation exposure.


Assuntos
Aberrações Cromossômicas/efeitos dos fármacos , Lesões por Radiação/tratamento farmacológico , Tocotrienóis/administração & dosagem , Vitamina E/administração & dosagem , Animais , Antioxidantes/administração & dosagem , Células da Medula Óssea/efeitos dos fármacos , Células Cultivadas , Quebras de DNA de Cadeia Dupla/efeitos dos fármacos , Reparo do DNA/efeitos dos fármacos , Enzimas Reparadoras do DNA/genética , Feminino , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Radiação Ionizante
12.
Environ Res ; 150: 470-481, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27419368

RESUMO

Long Interspersed Nucleotide Element 1 (LINE-1) retrotransposons are heavily methylated and are the most abundant transposable elements in mammalian genomes. Here, we investigated the differential DNA methylation within the LINE-1 under normal conditions and in response to environmentally relevant doses of sparsely and densely ionizing radiation. We demonstrate that DNA methylation of LINE-1 elements in the lungs of C57BL6 mice is dependent on their evolutionary age, where the elder age of the element is associated with the lower extent of DNA methylation. Exposure to 5-aza-2'-deoxycytidine and methionine-deficient diet affected DNA methylation of selective LINE-1 elements in an age- and promoter type-dependent manner. Exposure to densely IR, but not sparsely IR, resulted in DNA hypermethylation of older LINE-1 elements, while the DNA methylation of evolutionary younger elements remained mostly unchanged. We also demonstrate that exposure to densely IR increased mRNA and protein levels of LINE-1 via the loss of the histone H3K9 dimethylation and an increase in the H3K4 trimethylation at the LINE-1 5'-untranslated region, independently of DNA methylation. Our findings suggest that DNA methylation is important for regulation of LINE-1 expression under normal conditions, but histone modifications may dictate the transcriptional activity of LINE-1 in response to exposure to densely IR.


Assuntos
Metilação de DNA/efeitos da radiação , Elementos Nucleotídeos Longos e Dispersos/genética , Radiação Ionizante , Animais , Azacitidina/análogos & derivados , Azacitidina/farmacologia , Decitabina , Histonas/metabolismo , Elementos Nucleotídeos Longos e Dispersos/fisiologia , Pulmão/metabolismo , Pulmão/efeitos da radiação , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Células RAW 264.7
14.
Carcinogenesis ; 36 Suppl 1: S128-59, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26106135

RESUMO

The purpose of this review is to stimulate new ideas regarding low-dose environmental mixtures and carcinogens and their potential to promote invasion and metastasis. Whereas a number of chapters in this review are devoted to the role of low-dose environmental mixtures and carcinogens in the promotion of invasion and metastasis in specific tumors such as breast and prostate, the overarching theme is the role of low-dose carcinogens in the progression of cancer stem cells. It is becoming clearer that cancer stem cells in a tumor are the ones that assume invasive properties and colonize distant organs. Therefore, low-dose contaminants that trigger epithelial-mesenchymal transition, for example, in these cells are of particular interest in this review. This we hope will lead to the collaboration between scientists who have dedicated their professional life to the study of carcinogens and those whose interests are exclusively in the arena of tissue invasion and metastasis.


Assuntos
Carcinógenos Ambientais/efeitos adversos , Invasividade Neoplásica/patologia , Metástase Neoplásica/patologia , Animais , Progressão da Doença , Exposição Ambiental/efeitos adversos , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Humanos
15.
J Diet Suppl ; : 1-18, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38562009

RESUMO

Acetaminophen (APAP) overdose is one of the most common causes of acute liver injury. The current standard-of-care treatment for APAP hepatotoxicity, N-acetyl-l-cysteine, is highly effective when administered early after overdose, but loses efficacy in later-presenting patients. As a result, there is interest in the identification of new treatments for APAP overdose patients. Natural products are a promising source of new treatments because many are purported to have hepatoprotective effects. In fact, a great deal of research has been done to identify natural products that can protect against APAP-induced liver injury. However, serious concerns have been raised about the rigor and human relevance of these studies. Here, we systematically reviewed the APAP-natural product literature from 2013 to 2023 to determine the veracity of these concerns and the scope of the potential problem. The results substantiate the concerns that have been previously raised and point to concrete steps that can be taken to improve APAP-natural product research.

16.
Carcinogenesis ; 34(8): 1900-6, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23568954

RESUMO

The reversibility of non-genotoxic phenotypic alterations has been explored in order to develop novel preventive and therapeutic approaches for cancer control. Previously, it has been demonstrated that histone deacetylase (HDAC) inhibitor tributyrin, a butyric acid prodrug, to have chemopreventive effects on rat hepatocarcinogenesis. The goal of this study was to determine molecular mechanisms associated with the chemopreventive activity of tributyrin. Male Wistar rats were allocated randomly to untreated control group and two experimental groups. Rats in the experimental group 1 were treated with maltodextrin (3g/kg body wt), and rats in experimental group 2 were treated with tributyrin (2g/kg body wt) daily for 8 weeks. Two weeks after treatment initiation, rats from experimental groups were subjected to a 'resistant hepatocyte' model of hepatocarcinogenesis. Treatment with tributyrin resulted in lower HDAC activity and Hdac3 and Hdac4 gene expression, and an increase of histone H3 lysine 9 and 18 and histone H4 lysine 16 acetylation as compared with the experimental group 1. In addition to the increase in histone acetylation, tributyrin caused an increase in the acetylation of the nuclear p53 protein. These changes were accompanied by a normalization of the p53-signaling network, particularly by the upregulation of pro-apoptotic genes, and a consequent increase of apoptosis and autophagy in the livers of tributyrin-treated rats. These results indicate that the chemopreventive activity of tributyrin may be related to an increase of histone and p53 acetylation, which could lead to the induction of the p53 apoptotic pathway.


Assuntos
Apoptose/efeitos dos fármacos , Ácido Butírico/farmacologia , Neoplasias Hepáticas Experimentais/metabolismo , Neoplasias Hepáticas Experimentais/prevenção & controle , Pró-Fármacos/farmacologia , Triglicerídeos/farmacologia , Proteína Supressora de Tumor p53/genética , Acetilação , Animais , Apoptose/genética , Carcinogênese/genética , Carcinogênese/metabolismo , Carcinogênese/patologia , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Hepatócitos/patologia , Inibidores de Histona Desacetilases/farmacologia , Histona Desacetilases/genética , Histona Desacetilases/metabolismo , Histonas/genética , Histonas/metabolismo , Neoplasias Hepáticas Experimentais/genética , Neoplasias Hepáticas Experimentais/patologia , Lisina/genética , Lisina/metabolismo , Masculino , Lesões Pré-Cancerosas/tratamento farmacológico , Lesões Pré-Cancerosas/genética , Lesões Pré-Cancerosas/metabolismo , Lesões Pré-Cancerosas/patologia , Distribuição Aleatória , Ratos , Ratos Wistar , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Proteína Supressora de Tumor p53/metabolismo , Regulação para Cima/efeitos dos fármacos
17.
Mol Carcinog ; 52(4): 318-27, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22213190

RESUMO

Carcinogenesis is a multistep sequential process of clonal expansion of initiated cells associated with the accumulation of multiple cancer-specific heritable phenotypes. The acquisition of these heritable cancer-specific alterations may be triggered by mutational and/or non-mutational changes in the genome that affect the regulation of gene expression. Currently, cancer-specific epigenetically mediated changes in gene expression are regarded as driving events in tumorigenesis. In the present study, we investigated the role of gene-specific expression changes in the mechanism of rat hepatocarcinogenesis induced by the complete hepatocarcinogen 2-acetylaminofluorene (2-AAF). The results of the present study demonstrate significant alterations in gene expression, especially of Mat1a and Mthfr genes, during early stages of rat 2-AAF-induced liver carcinogenesis. Both of these genes were downregulated in the livers of 2-AAF-treated male rats. Inhibition of Mat1a expression was associated with an increase in histone H3 lysine 27 trimethylation and a decrease in histone H3 lysine 18 acetylation at the gene promoter/first exon region. Additionally, we demonstrate for the first time a critical contribution of miR-22 and miR-29b microRNAs in the inhibition of Mat1a and Mthfr gene expression during 2-AAF-induced rat hepatocarcinogenesis. The downregulation of Mat1a and Mthfr genes was accompanied by marked functional alterations in one-carbon metabolism. The results of the present study suggest that downregulation of the Mat1a and Mthfr genes may be one of the main driver events that promote liver carcinogenesis by causing a profound accumulation of subsequent epigenetic abnormalities during progression of the carcinogenic process.


Assuntos
Regulação Neoplásica da Expressão Gênica , Neoplasias Hepáticas Experimentais/genética , Fígado/metabolismo , Metionina Adenosiltransferase/genética , Metilenotetra-Hidrofolato Redutase (NADPH2)/genética , MicroRNAs/genética , 2-Acetilaminofluoreno , Acetilação , Animais , Carcinógenos , Linhagem Celular , Metilação de DNA , Regulação para Baixo , Epigênese Genética , Feminino , Histonas/genética , Histonas/metabolismo , Fígado/efeitos dos fármacos , Neoplasias Hepáticas Experimentais/induzido quimicamente , Neoplasias Hepáticas Experimentais/metabolismo , Masculino , Regiões Promotoras Genéticas , Ratos , Ratos Sprague-Dawley , S-Adenosil-Homocisteína/análise , S-Adenosil-Homocisteína/metabolismo , S-Adenosilmetionina/análise , S-Adenosilmetionina/metabolismo
18.
FASEB J ; 26(11): 4592-602, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22872676

RESUMO

Nonalcoholic fatty liver disease (NAFLD) is a major health problem and a leading cause of chronic liver disease in the United States and developed countries. In humans, genetic factors greatly influence individual susceptibility to NAFLD. The goals of this study were to compare the magnitude of interindividual differences in the severity of liver injury induced by methyl-donor deficiency among individual inbred strains of mice and to investigate the underlying mechanisms associated with the variability. Feeding mice a choline- and folate-deficient diet for 12 wk caused liver injury similar to NAFLD. The magnitude of liver injury varied among the strains, with the order of sensitivity being A/J ≈ C57BL/6J ≈ C3H/HeJ < 129S1/SvImJ ≈ CAST/EiJ < PWK/PhJ < WSB/EiJ. The interstrain variability in severity of NAFLD liver damage was associated with dysregulation of genes involved in lipid metabolism, primarily with a down-regulation of the peroxisome proliferator receptor α (PPARα)-regulated lipid catabolic pathway genes. Markers of oxidative stress and oxidative stress-induced DNA damage were also elevated in the livers but were not correlated with severity of liver damage. These findings suggest that the PPARα-regulated metabolism network is one of the key mechanisms determining interstrain susceptibility and severity of NAFLD in mice.


Assuntos
Deficiência de Colina/complicações , Colina/administração & dosagem , Fígado Gorduroso/etiologia , Deficiência de Ácido Fólico/complicações , Ácido Fólico/administração & dosagem , Metabolismo dos Lipídeos/genética , Ração Animal , Animais , Sistema Enzimático do Citocromo P-450/genética , Sistema Enzimático do Citocromo P-450/metabolismo , Dano ao DNA , Dieta , Fígado Gorduroso/patologia , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/fisiologia , Variação Genética , Masculino , Camundongos , Camundongos Endogâmicos , Estresse Oxidativo , Análise Serial de Proteínas , Transcriptoma
19.
J Diet Suppl ; 20(6): 950-962, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36469606

RESUMO

Methylsulfonylmethane (MSM), a natural organosulfur compound, is a popular dietary supplement sold both as a single product and as a constituent of multi-ingredient products. It has been postulated that MSM may serve as a donor for methyl groups for various cellular processes; however, studies have yet to demonstrate this. Therefore, the goal of this study was to determine whether or not MSM, supplemented to fully differentiated human HepaRG cells at physiologically-relevant concentrations, can serve as a donor for methyl groups for DNA methylation. For this purpose, methyl groups in the MSM molecule were labeled with deuterium (deuterated) and incorporation of the labeled 5-methylcytosine into the HepaRG cell DNA was evaluated using liquid chromatography/mass spectrometry (LC-MS/MS). We report that MSM supplementation resulted in significant incorporation of deuterated product into DNA in a time- and dose-dependent fashion. These changes were not associated with increased 5-methylcytosine content, did not result in changes of DNA methylation or re-distribution of DNA methylation patterns between the retrotransposons LINE-1 and HERV18, and were not associated with cytotoxicity. In conclusion, short-term supplementation with MSM in vitro demonstrates that MSM can serve as a donor of methyl groups for methylation of DNA, but does not affect the levels of DNA methylation globally and does not lead to redistribution of the DNA methylation patterns within the most abundant repetitive elements. Future studies will be needed to validate these findings in vivo and to investigate whether or not MSM can restore normal DNA methylation patterns within the hypomethylated phenotype.


Assuntos
5-Metilcitosina , Espectrometria de Massas em Tandem , Humanos , Metilação , 5-Metilcitosina/metabolismo , Cromatografia Líquida , Fígado/metabolismo , DNA
20.
J Diet Suppl ; 20(2): 171-198, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36178162

RESUMO

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel coronavirus responsible for the COVID-19 pandemic that can lead to severe respiratory distress requiring hospitalization and can be fatal. Media have reported that various dietary supplements (DS) or their combination with different medications can prevent infection or decrease disease severity. Here, we analyzed data collected from 15,830 patient follow-up telephone interviews from the University of Arkansas for Medical Sciences COVID-19 testing sites from March 15 to August 1, 2020. Within the REDCap database, we recorded patient demographics and DS and medication use. In total, data on DS and medication use was available for 8,150 study participants, of whom 21.9% and 4.1% reported using DS or medications, respectively, to either prevent or treat COVID-19. The majority of respondents were female (64%) and non-Hispanic whites (44.5%). Most individuals (64.5%) who took DS were younger than 50 years of age. Products such as vitamin C (1,013, 33.2%), multivitamins (722, 23.6%), and vitamin D (294, 9.6%) were the most commonly used DS among the responders. Analysis of the DS use and symptom scores association did not provide a strong evidence of beneficial health effects of DS. The results of this study demonstrate that a significantly higher proportion of study participants considered usage of DS to mitigate or prevent COVID-19-related symptoms compared to those who preferred medications. However, lack of observable health benefits associated with ingestion of DS suggests that more rigorous research is needed to substantiate the label claims.


Assuntos
COVID-19 , Humanos , Masculino , Feminino , SARS-CoV-2 , Arkansas/epidemiologia , Pandemias/prevenção & controle , Teste para COVID-19 , Suplementos Nutricionais , Vitaminas/uso terapêutico
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA