ABSTRACT
Sirtuins (SIRTs) belong to the nicotinamide adenine dinucleotide (NAD+)-dependent class III histone deacetylase family. They are key regulators of cellular and physiological processes, such as cell survival, senescence, differentiation, DNA damage and stress response, cellular metabolism, and aging. SIRTs also influence carcinogenesis, making them potential targets for anticancer therapeutic strategies. In this study, we investigated the anticancer properties and underlying molecular mechanisms of a novel SIRT1 inhibitor, MHY2251, in human colorectal cancer (CRC) cells. MHY2251 reduced the viability of various human CRC cell lines, especially those with wild-type TP53. MHY2251 inhibited SIRT1 activity and SIRT1/2 protein expression, while promoting p53 acetylation, which is a target of SIRT1 in HCT116 cells. MHY2251 treatment triggered apoptosis in HCT116 cells. It increased the percentage of late apoptotic cells and the sub-G1 fraction (as detected by flow cytometric analysis) and induced DNA fragmentation. In addition, MHY2251 upregulated the expression of FasL and Fas, altered the ratio of Bax/Bcl-2, downregulated the levels of pro-caspase-8, -9, and -3 proteins, and induced subsequent poly(ADP-ribose) polymerase cleavage. The induction of apoptosis by MHY2251 was related to the activation of the caspase cascade, which was significantly attenuated by pre-treatment with ZVAD-FMK, a pan-caspase inhibitor. Furthermore, MHY2251 stimulated the phosphorylation of c-Jun N-terminal kinase (JNK), and MHY2251-triggered apoptosis was blocked by pre-treatment with SP600125, a JNK inhibitor. This finding indicated the specific involvement of JNK in MHY2251-induced apoptosis. MHY2251 shows considerable potential as a therapeutic agent for targeting human CRC via the inhibition of SIRT1 and activation of JNK/p53 pathway.
ABSTRACT
1,2-Diacetylbenzene (DAB) is a metabolite of 1,2-diethylbenzene, which is commonly used in the manufacture of plastics and gasoline. We examined the neurotoxic effects of DAB in young and old rats, particularly its effects on hippocampus. Previously, we reported DAB impairs hippocampal neurogenesis but that the underlying mechanism remained unclear. In this study, we evaluate the toxicities exhibited by DAB in the hippocampi of 6-month-old (young) and 20-month-old (old) male SD rats by treating animals intraperitoneally with DAB at 3 mg/kg/day for 1 week. Hippocampal areas were dissected from brains and RNA was extracted and subjected to RNA-seq analysis. RNA results showed animals exhibited age-dependent sensitivity to the neurotoxic effects of DAB. We observed that inflammatory pathways were up-regulated in old rats but that metabolism- and detoxification-related pathways were up-regulated in young rats. This result in old rats, especially upregulation of the TREM1 signaling pathway (an inflammatory response involved in Alzheimer’s disease (AD)) was confirmed by RT-PCR. Our study results provide a better understanding of age-dependent responses to DAB and new insight into the association between DAB and AD.
ABSTRACT
1,2-Diacetylbenzene (DAB) is a metabolite of 1,2-diethylbenzene, which is commonly used in the manufacture of plastics and gasoline. We examined the neurotoxic effects of DAB in young and old rats, particularly its effects on hippocampus. Previously, we reported DAB impairs hippocampal neurogenesis but that the underlying mechanism remained unclear. In this study, we evaluate the toxicities exhibited by DAB in the hippocampi of 6-month-old (young) and 20-month-old (old) male SD rats by treating animals intraperitoneally with DAB at 3 mg/kg/day for 1 week. Hippocampal areas were dissected from brains and RNA was extracted and subjected to RNA-seq analysis. RNA results showed animals exhibited age-dependent sensitivity to the neurotoxic effects of DAB. We observed that inflammatory pathways were up-regulated in old rats but that metabolism- and detoxification-related pathways were up-regulated in young rats. This result in old rats, especially upregulation of the TREM1 signaling pathway (an inflammatory response involved in Alzheimer’s disease (AD)) was confirmed by RT-PCR. Our study results provide a better understanding of age-dependent responses to DAB and new insight into the association between DAB and AD.
ABSTRACT
Background@#Protease-activated protein-2 (PAR2) has been reported to regulate hepatic insulin resistance condition in type 2 diabetes mice. However, the mechanism of lipid metabolism through PAR2 in obesity mice have not yet been examined. In liver, Forkhead box O1 (FoxO1) activity induces peroxisome proliferator-activated receptor γ (PPARγ), leading to accumulation of lipids and hyperlipidemia. Hyperlipidemia significantly influence hepatic steatoses, but the mechanisms underlying PAR2 signaling are complex and have not yet been elucidated. @*Methods@#To examine the modulatory action of FoxO1 and its altered interaction with PPARγ, we utilized db/db mice and PAR2-knockout (KO) mice administered with high-fat diet (HFD). @*Results@#Here, we demonstrated that PAR2 was overexpressed and regulated downstream gene expressions in db/db but not in db+ mice. The interaction between PAR2/β-arrestin and Akt was also greater in db/db mice. The Akt inhibition increased FoxO1 activity and subsequently PPARγ gene in the livers that led to hepatic lipid accumulation. Our data showed that FoxO1 was negatively controlled by Akt signaling and consequently, the activity of a major lipogenesis-associated transcription factors such as PPARγ increased, leading to hepatic lipid accumulation through the PAR2 pathway under hyperglycemic conditions in mice. Furthermore, the association between PPARγ and FoxO1 was increased in hepatic steatosis condition in db/db mice. However, HFD-fed PAR2-KO mice showed suppressed FoxO1-induced hepatic lipid accumulation compared with HFD-fed control groups. @*Conclusion@#Collectively, our results provide evidence that the interaction of FoxO1 with PPARγ promotes hepatic steatosis in mice. This might be due to defects in PAR2/β-arrestin-mediated Akt signaling in diabetic and HFD-fed mice.
ABSTRACT
We examined the anticancer effects of a novel sirtuin inhibitor, MHY2256, on HCT116 human colorectal cancer cells to investigate its underlying molecular mechanisms. MHY2256 significantly suppressed the activity of sirtuin 1 and expression levels of sirtuin 1/2 and stimulated acetylation of forkhead box O1, which is a target protein of sirtuin 1. Treatment with MHY2256 inhibited the growth of the HCT116 (TP53 wild-type), HT-29 (TP53 mutant), and DLD-1 (TP53 mutant) human colorectal cancer cell lines. In addition, MHY2256 induced G0/G1 phase arrest of the cell cycle progression, which was accompanied by the reduction of cyclin D1 and cyclin E and the decrease of cyclin-dependent kinase 2, cyclin-dependent kinase 4, cyclin-dependent kinase 6, phosphorylated retinoblastoma protein, and E2F transcription factor 1. Apoptosis induction was shown by DNA fragmentation and increase in late apoptosis, which were detected using flow cytometric analysis. MHY2256 downregulated expression levels of procaspase-8, -9, and -3 and led to subsequent poly(ADP-ribose) polymerase cleavage. MHY2256-induced apoptosis was involved in the activation of caspase-8, -9, and -3 and was prevented by pretreatment with Z-VAD-FMK, a pan-caspase inhibitor. Furthermore, the autophagic effects of MHY2256 were observed as cytoplasmic vacuolation, green fluorescent protein-light-chain 3 punctate dots, accumulation of acidic vesicular organelles, and upregulated expression level of light-chain 3-II. Taken together, these results suggest that MHY2256 could be a potential novel sirtuin inhibitor for the chemoprevention or treatment of colorectal cancer or both.
ABSTRACT
Apigenin (4′,5,7-trihydroxyflavone) is a flavonoid commonly found in many fruits and vegetables such as parsley, chamomile, celery, and kumquats. In the last few decades, recognition of apigenin as a cancer chemopreventive agent has increased. Significant progress has been made in studying the chemopreventive aspects of apigenin both in vitro and in vivo. Several studies have demonstrated that the anticarcinogenic properties of apigenin occur through regulation of cellular response to oxidative stress and DNA damage, suppression of inflammation and angiogenesis, retardation of cell proliferation, and induction of autophagy and apoptosis. One of the most well-recognized mechanisms of apigenin is the capability to promote cell cycle arrest and induction of apoptosis through the p53-related pathway. A further role of apigenin in chemoprevention is the induction of autophagy in several human cancer cell lines. In this review, we discuss the details of apigenin, apoptosis, autophagy, and the role of apigenin in cancer chemoprevention via the induction of apoptosis and autophagy.
Subject(s)
Humans , Apigenin , Apium , Apoptosis , Autophagy , Cell Cycle Checkpoints , Cell Line , Cell Proliferation , Chamomile , Chemoprevention , DNA Damage , Fruit , In Vitro Techniques , Inflammation , Oxidative Stress , Petroselinum , Rutaceae , VegetablesABSTRACT
To explore the anti-allergic and anti-inflammatory effects of extracts of Petasites genus, we studied the effects of s-petasin, a major sesquiterpene from Petasites formosanus (a butterbur species) on asthma and peritonitis models. In an ovalbumin-induced mouse asthma model, s-petasin significantly inhibited the accumulations of eosinophils, macrophages, and lymphocytes in bronchoalveolar fluids. S-petasin inhibited the antigen-induced degranulation of beta-hexosamidase but did not inhibit intracellular Ca2+ increase in RBL-2H3 mast cells. S-petasin inhibited the LPS induction of iNOS at the RNA and protein levels in mouse peritoneal macrophages. Furthermore, s-petasin inhibited the production of NO (the product of iNOS) in a concentration-dependent manner in the macrophages. Furthermore, in an LPS-induced mouse model of peritonitis, s-petasin significantly inhibited the accumulation of polymorpho nuclear and mononuclear leukocytes in peritoneal cavity. This study shows that s-petasin in Petasites genus has therapeutic effects on allergic and inflammatory diseases, such as, asthma and peritonitis through degranulation inhibition in mast cells, suppression of iNOS induction and production of NO in macrophages, and suppression of inflammatory cell accumulation.
Subject(s)
Animals , Mice , Asthma , Eosinophils , Leukocytes, Mononuclear , Lymphocytes , Macrophages , Macrophages, Peritoneal , Mast Cells , Peritoneal Cavity , Peritonitis , Petasites , RNAABSTRACT
BACKGROUND: The effect of caloric restriction (CR) in the setting of diabetes on bone metabolism has not yet been fully studied. The aim of this study is to determine if short-term CR alters bone mass and metabolism in Otsuka Long-Evans Tokushima fatty (OLETF) rats, an animal model of type 2 diabetes. METHODS: Four groups (n=5) were created: OLETF rats with food ad libitum (AL), OLETF rats with CR, Long-Evans Tokusima Otsuka (LETO) rats with food AL, and LETO rats with CR. The CR condition was imposed on 24-week-old male rats using a 40% calorie reduction for 4 weeks. The effect of CR on femoral bone mineral density (BMD) was assessed by dual-energy X-ray absorptiometry. Serum markers were measured by immunoassay. RESULTS: After 4 weeks of CR, body weight decreased in both strains. The BMD decreased in LETO rats and was maintained in OLETF rats. After adjustment for body weight, BMD remained lower in LETO rats (P=0.017) but not OLETF rats (P=0.410). Bone-specific alkaline phosphatase levels decreased in LETO rats (P=0.025) but not in OLEFT rats (P=0.347). Serum leptin levels were reduced after CR in both strains, but hyperleptinemia remained in OLETF rats (P=0.009). CR increased 25-hydroxyvitamin D levels in OLETF rats (P=0.009) but not in LETO rats (P=0.117). Additionally, interleukin-6 and tumor necrosis factor-alpha levels decreased only in OLETF rats (P=0.009). CONCLUSION: Short-term CR and related weight loss were associated with decreases of femoral BMD in LETO rats while BMD was maintained in OLETF rats. Short-term CR may not alter bone mass and metabolism in type 2 diabetic rats.
Subject(s)
Animals , Humans , Male , Rats , Absorptiometry, Photon , Alkaline Phosphatase , Body Weight , Bone Density , Caloric Restriction , Diabetes Mellitus, Type 2 , Immunoassay , Interleukin-6 , Leptin , Metabolism , Models, Animal , Rats, Inbred OLETF , Tumor Necrosis Factor-alpha , Weight Loss , BiomarkersABSTRACT
With the rapid development of MS technologiesy, the demands for a more sophisticated MS interpretation algorithm haves grown as well. We have developed a new protein fingerprinting method using a binomial distribution, (fBIND). With the fBIND, we improved the performance accuracy of protein fingerprinting up to the maximum 49% (more than MOWSE) and 2% than(at a previous binomial distribution approach studied by of Wool et al.) as compared to the established algorithms. Moreover, we also suggest a the statistical approach to define the significance of transcription factors and motifs in the identified proteins based on the Gene Ontology (GO).
Subject(s)
Binomial Distribution , Fungal Proteins , Gene Ontology , Peptide Mapping , Transcription Factors , Wool , YeastsABSTRACT
The involvement of NF-kappaB binding activity is known to be important in the mechanism of acute liver injury and in the induction of cyclooxygenase (COX-2). This study was performed to evaluate NF-kappaB binding activity and the expression of COX-2 in chronic liver injury induced by carbon tetrachloride (betaCCI(4)). Liver tissues from Sprague - Dawley rats were collected at 1, 3, 5, and 7th week after intraperitoneal injection of 0.1 mL of betaCCI(4)/100 g body weight twice a week. Reactive oxy-gen species (ROS) were measured in the postmitochondrial fraction by dichlorofluorescein formation with a fluorescent probe. An electrophoretic mobility shift assay was performed for NF-kappaB binding activity. Western blot was performed to measure the level of COX-1, COX-2, p65, p50, and I B proteins. ROS and NF-kappaB activity increased during the CCl4-induced chronic liver injury. The expression of nuclear p65 protein and p50 protein increased compared with that of the control, while the cytoplasmic I B protein decreased as the inflammation persisted. The expression of COX-2 in betaCCI(4)-treated rat liver increased compared with that of the control. It could be suggested that ROS produced by betaCCI(4) treatment increased NF-kappaB binding activity and thereby COX-2 expression, and these might be implicated in the progress of chronic liver damage.
Subject(s)
Animals , Rats , Biological Transport , Carbon Tetrachloride/administration & dosage , Carbon Tetrachloride Poisoning/metabolism , Cell Nucleus/metabolism , Cyclooxygenase 1 , Cyclooxygenase 2 , Cytoplasm/metabolism , I-kappa B Proteins/biosynthesis , Isoenzymes/biosynthesis , Liver/drug effects , Membrane Proteins , NF-kappa B/antagonists & inhibitors , NF-kappa B p50 Subunit , Prostaglandin-Endoperoxide Synthases/biosynthesis , Protein Binding , Rats, Sprague-Dawley , Reactive Oxygen Species , Transcription Factor RelAABSTRACT
No abstract available.