共查询到20条相似文献,搜索用时 15 毫秒
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Background
The gene for methylthioadenosine phosphorylase (MTAP) lies on 9p21, close to the gene CDKN2A that encodes the tumor suppressor proteins p16 and p14ARF. MTAP and CDKN2A are homozygously co-deleted, with a frequency of 35 to 70%, in lung and pancreatic cancer, glioblastoma, osteosarcoma, soft-tissue sarcoma, mesothelioma, and T-cell acute lymphoblastic leukemia. In normal cells, but not in tumor cells lacking MTAP, MTAP cleaves the natural substrate, 5′-deoxy-5′-methylthioadenosine (MTA), to adenine and 5-methylthioribose-1-phosphate (MTR-1-P), which are then converted to adenine nucleotides and methionine. This distinct difference between normal MTAP-positive cells and tumor MTAP-negative cells led to several proposals for therapy. We offer a novel strategy in which both MTA and a toxic adenine analog, such as 2,6-diaminopurine (DAP), 6-methylpurine (MeP), or 2-fluoroadenine (F-Ade), are administered. In MTAP-positive cells, abundant adenine, generated from supplied MTA, competitively blocks the conversion of an analog, by adenine phosphoribosyltransferase (APRT), to its active nucleotide form. In MTAP-negative tumor cells, the supplied MTA cannot generate adenine; hence conversion of the analog is not blocked.Principal Findings
We show that this combination treatment – adenine analog plus MTA – kills MTAP-negative A549 lung tumor cells, while MTAP-positive human fibroblasts (HF) are protected. In co-cultures of the breast tumor cell line, MCF-7, and HF cells, MCF-7 is inhibited or killed, while HF cells proliferate robustly. 5-fluorouracil (5-FU) and 6-thioguanine (6-TG) may also be used with our strategy. Though neither analog is activated by APRT, in MTAP-positive cells, adenine produced from supplied MTA blocks conversion of 5-FU and 6-TG to their toxic nucleotide forms by competing for 5-phosphoribosyl-1-pyrophosphate (PRPP). The combination of MTA with 5-FU or 6-TG, in the treatment of MTAP-negative tumors, may produce a significantly improved therapeutic index.Conclusion
We describe a selective strategy to kill tumor cells lacking MTAP. 相似文献3.
Partha K. Chandra Feyza Gunduz Sidhartha Hazari Ramazan Kurt Rajesh Panigrahi Bret Poat David Bruce Ari J. Cohen Humberto E. Behorquez Ian Carmody George Loss Luis A. Balart Tong Wu Srikanta Dash 《PloS one》2014,9(9)
Purpose
Chronic Hepatitis C Virus (HCV)-infected patients with liver cirrhosis (LC) respond poorly to interferon-alpha (IFN-α) and ribavirin (RBV) combination therapy, but the reason for this is unclear. We previously reported that HCV-infection induces endoplasmic reticulum (ER) stress and autophagy response that selectively down regulates the type I IFN-α receptor-1 (IFNAR1) and RBV transporters (CNT1 and ENT1), leading to IFN-α/RBV resistance. The goal of this study is to verify whether an increase in ER stress and autophagy response is also associated with the reduced expression of IFNAR1 and RBV transporters in chronic HCV-infected patients.Methods
Primary human hepatocytes (PHH) were infected with cell culture grown HCV particles (JFH-ΔV3-Rluc). HCV replication was confirmed by the detection of viral RNA by RT-qPCR and HCV-core protein by Western blotting. The ER stress and autophagy response and expression of IFN receptors and RBV transporters in HCV infected PHH and liver tissues derived from patients were measured by Western blotting.Result
HCV infection of PHH showed impaired expression of IFNAR1, IFNγR1 (Type II IFN receptor) and RBV transporters but not IL10Rβ (Type III IFN-λ receptor). ER stress markers (BiP, IRE1α and peIF2α) and autophagy response (LC3II, Beclin 1 and ATG5) were induced in HCV infected chronic liver disease (CLD) and LC patients. Liver biopsies (CLD) show a 50% reduced expression of IFNAR1 and RBV transporters. Furthermore, the expression of IFNAR1 and RBV transporters was impaired in almost all LC patients.Conclusion
HCV infection induces ER stress and autophagy response in infected PHH and chronically infected liver tissues. The expression of IFNAR1, IFNγR1 and RBV transporters were significantly impaired in CLD and cirrhotic livers. Our study provides a potential explanation for the reduced response rate of IFN-α and RBV combination therapy in HCV infected patients with liver cirrhosis. 相似文献4.
Chunyan Zhang Yabin Zhao Mengli Yu Jianru Qin Bingyu Ye Qiwen Wang 《Current issues in molecular biology》2022,44(7):3156
Mitochondria are generally considered the powerhouse of the cell, a small subcellular organelle that produces most of the cellular energy in the form of adenosine triphosphate (ATP). In addition, mitochondria are involved in various biological functions, such as biosynthesis, lipid metabolism, oxidative phosphorylation, cell signal transduction, and apoptosis. Mitochondrial dysfunction is manifested in different aspects, like increased mitochondrial reactive oxygen species (ROS), mitochondrial DNA (mtDNA) damage, adenosine triphosphate (ATP) synthesis disorder, abnormal mitophagy, as well as changes in mitochondrial morphology and structure. Mitochondrial dysfunction is related to the occurrence and development of various chronic liver diseases, including hepatocellular carcinoma (HCC), viral hepatitis, drug-induced liver injury (DILI), alcoholic fatty liver (AFL), and non-alcoholic fatty liver (NAFL). In this review, we summarize and discuss the role and mechanisms of mitochondrial dysfunction in chronic liver disease, focusing on and discussing some of the latest studies on mitochondria and chronic liver disease. 相似文献
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《Endocrine practice》2022,28(10):1062-1068
ObjectiveHypercalcemia is sometimes observed in patients with cirrhosis, but very little is known about the epidemiology in patients with hypercalcemia of chronic liver disease (HCLD) or how its presence may modulate the overall mortality risk. We assessed the associations between the clinical and laboratory characteristics of patients with HCLD with 90-day mortality.MethodsA systematic search of the medical records at our institution over a 10-year period was performed to retrospectively identify subjects with HCLD during inpatient admission. Univariate and multivariable regression analyses were performed to detect the risk factors for all-cause 90-day mortality.ResultsThirty-eight subjects with HCLD were identified using stringent inclusion and exclusion criteria to exclude individuals with other secondary causes of hypercalcemia. A total of 35 subjects had 90-day vital status available, which revealed 40% mortality. The model for end-stage liver disease sodium score and duration of inpatient hypercalcemia were positively associated with mortality with respective odds ratios of 1.23 (95% CI, 1.06-3.23) and 1.24 (95% CI, 1.04-1.49) in a univariate regression model and 1.30 (95% CI, 1.04-1.62) and 1.33 (95% CI, 1.04-1.71) in a multivariable regression model. The admission and peak serum calcium levels were not associated with mortality. Only 6 subjects received bisphosphonates or calcitonin during their admission, limiting our ability to assess the impact of treatment on outcomes.ConclusionIn patients admitted to the hospital with HCLD, the duration of hypercalcemia was positively associated with 90-day mortality, providing a potential interventional target to reduce mortality in this high-risk population. Studies to validate the utility of treating hypercalcemia are required. 相似文献
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Hui Zhang Xiao Sun Wenjie Li Tuoping Li Suhong Li Motomitsu Kitaoka 《The protein journal》2018,37(1):93-100
SPase is widely used in the food, cosmetics, and pharmaceutical industries. Previously, a SPase gene was cloned from Bifidobacterium longum JCM1217 and constructed into Escherichia coli BL21. In this paper, its expression conditions were optimized. The results showed that several induction factors determined the expression efficiency of SPase. The initial cell density, IPTG concentration, and induction time and temperature significantly (p?<?0.01) affected the total protein content and activity of expressed SPase. The highest expression efficiency was obtained at an initial cell density of OD600?=?0.5, with 0.05 mM IPTG, followed by shaking at 180 rpm and incubation at 30 °C for 15 h. The purified SPase had a specific activity of 122.1 U/mg, which was raised by 1.85 -fold more than that before optimization, and its recovery yield was 86%. Furthermore, SPase also showed higher thermostability. The results of this study provide essential information for the industrial production of SPase. 相似文献
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J. G. Walker D. Bates D. Doniach P. A. J. Ball S. Sherlock 《BMJ (Clinical research ed.)》1972,1(5793):146-148
Two sisters had primary biliary disease and associated autoimmune thyroiditis with high titres of mitochondrial and other autoantibodies. Their deceased mother possibly suffered from similar disorders. In the same family two brothers had multiple autoimmune reactions, including mitochondrial antibodies, but liver function tests gave normal results. Ten other close relatives were investigated. Australia antigen was not found in the proband or her relatives. 相似文献
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L. Van Waes J. Segers J. Van Egmond L. Van Nimmen F. Barbier R. Wieme L. Demeulenaere 《BMJ (Clinical research ed.)》1974,3(5928):444-446
A long-term follow-up of 45 patients with chronic hepatitis and 41 with cirrhosis is reported. Hepatitis-B antigen (HBAg) was present in 19 (42%) of the chronic hepatitis patients and in 20 (49%) of those with cirrhosis. The clinical course and biochemical and histological findings in the HBAg-positive and the HBAg-negative cases were similar, suggesting that HBAg-positive chronic liver disease is not a distinct clinical entity. The presence of antigen and autoantibodies was not found to be mutually exclusive. In HBAg-positive cases antigen tended to persist for months and years. When no irreversible lesions exist disappearance of the antigen may be a sign that the liver disease will resolve. 相似文献
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《Free radical research》2013,47(6):373-377
The in vitro and in vivo effects of the naturally occuring Ravolignan hepatoprotective agent silibinin? on the expression and activity of superoxide dismutase (SOD) enzyme were studied in lymphocytes from patients with chronic alcoholic liver disease. In vitro incubation with silibinin in a concentration corresponding to the usual therapeutic dosage markedly increased the SOD — expression of lymphocytes as measured by Row-cytofluorimetry following staining with monoclonal anti-Cu, Zn-SOD — antibody and FITC-conjugated anti-mouse Ig. In vivo treatment with the drug restored the originally low SOD activity of the patients' lymphocytes. These data indirectly suggest that antioxidant activity might be one of the important factors in the hepatoprotective action of silibinin. 相似文献
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F. E. de W. Cayley 《BMJ (Clinical research ed.)》1949,2(4641):1386-1387
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目的:研究PPAR-γ在非酒精性脂肪性肝病(NAFLD)大鼠肝脏组织中的表达,探讨非酒精脂肪性肝病可能的发病机制。方法:雄性SD大鼠30只,随机分为A(正常组)15只普通饮食,B(高脂组)15只高脂饮食。8周后,自两组各随机抽取2只大鼠处死,光镜观察证实脂肪肝造模成功,继续喂养4周后处死所有大鼠,取血清做免疫生化检查,取肝组织标本,分别以光镜观察做出NAS评分,免疫组化和PCR法检测肝组织PPAR-γ蛋白的表达。结果:1.高脂饮食可以成功的复制NAFLD的大鼠模型;2.血清GLU、TC、TG、HDL-C、LDL-C在高脂组表达量较正常组明显升高,差异具有统计学意义(P〈0.05);3.免疫组化显示:高脂组PPAR-γ表达量较正常组升高;结论:1.高脂饮食可成功复制NAFLD模型;2.PPAR-γ在NAFLD大鼠肝脏成脂性改变中具有重要作用。 相似文献
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目的:研究PPAR-Y在非酒精性脂肪性肝病(NAFLD)大鼠肝脏组织中的表达,探讨非酒精脂肪性肝病可能的发病机制.方法:雄性SD大鼠30只,随机分为A(正常组)15只普通饮食,B(高脂组)15只高脂饮食.8周后,自两组各随机抽取2只大鼠处死,光镜观察证实脂肪肝造模成功,继续喂养4周后处死所有大鼠,取血清做免疫生化检查,取肝组织标本,分别以光镜观察做出NAS评分,免疫组化和PCR法检测肝组织PPAR-Y蛋白的表达.结果:1.高脂饮食可以成功的复制NAFLD的大鼠模型;2.血清GLU、TC、TG、HDL-C、LDLC在高脂组表达量较正常组明显升高,差异具有统计学意义(P<0.05);3.免疫组化显示:高脂组PPAR-Y表达量较正常组升高;结论:1.高脂饮食可成功复制NAFLD模型;2.PPAR-Y在NAFLD大鼠肝脏成脂性改变中具有重要作用. 相似文献
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Jack X. Q. Pang Scott Zimmer Sophia Niu Pam Crotty Jenna Tracey Faruq Pradhan Abdel Aziz M. Shaheen Carla S. Coffin Steven J. Heitman Gilaad G. Kaplan Mark G. Swain Robert P. Myers 《PloS one》2014,9(4)
Background
Liver stiffness measurement (LSM) by transient elastography (TE, FibroScan) is a validated method for noninvasively staging liver fibrosis. Most hepatic complications occur in patients with advanced fibrosis. Our objective was to determine the ability of LSM by TE to predict hepatic complications and mortality in a large cohort of patients with chronic liver disease.Methods
In consecutive adults who underwent LSM by TE between July 2008 and June 2011, we used Cox regression to determine the independent association between liver stiffness and death or hepatic complications (decompensation, hepatocellular carcinoma, and liver transplantation). The performance of LSM to predict complications was determined using the c-statistic.Results
Among 2,052 patients (median age 51 years, 65% with hepatitis B or C), 87 patients (4.2%) died or developed a hepatic complication during a median follow-up period of 15.6 months (interquartile range, 11.0–23.5 months). Patients with complications had higher median liver stiffness than those without complications (13.5 vs. 6.0 kPa; P<0.00005). The 2-year incidence rates of death or hepatic complications were 2.6%, 9%, 19%, and 34% in patients with liver stiffness <10, 10–19.9, 20–39.9, and ≥40 kPa, respectively (P<0.00005). After adjustment for potential confounders, liver stiffness by TE was an independent predictor of complications (hazard ratio [HR] 1.05 per kPa; 95% confidence interval [CI] 1.03–1.06). The c-statistic of liver-stiffness for predicting complications was 0.80 (95% CI 0.75–0.85). A liver stiffness below 20 kPa effectively excluded complications (specificity 93%, negative predictive value 97%); however, the positive predictive value of higher results was sub-optimal (20%).Conclusions
Liver stiffness by TE accurately predicts the risk of death or hepatic complications in patients with chronic liver disease. TE may facilitate the estimation of prognosis and guide management of these patients. 相似文献15.
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Kristen L. Jablonski Emily Decker Loni Perrenoud Jessica Kendrick Michel Chonchol Douglas R. Seals Diana Jalal 《Journal of visualized experiments : JoVE》2014,(88)
Patients with chronic kidney disease (CKD) have significantly increased risk of cardiovascular disease (CVD) compared to the general population, and this is only partially explained by traditional CVD risk factors. Vascular dysfunction is an important non-traditional risk factor, characterized by vascular endothelial dysfunction (most commonly assessed as impaired endothelium-dependent dilation [EDD]) and stiffening of the large elastic arteries. While various techniques exist to assess EDD and large elastic artery stiffness, the most commonly used are brachial artery flow-mediated dilation (FMDBA) and aortic pulse-wave velocity (aPWV), respectively. Both of these noninvasive measures of vascular dysfunction are independent predictors of future cardiovascular events in patients with and without kidney disease. Patients with CKD demonstrate both impaired FMDBA, and increased aPWV. While the exact mechanisms by which vascular dysfunction develops in CKD are incompletely understood, increased oxidative stress and a subsequent reduction in nitric oxide (NO) bioavailability are important contributors. Cellular changes in oxidative stress can be assessed by collecting vascular endothelial cells from the antecubital vein and measuring protein expression of markers of oxidative stress using immunofluorescence. We provide here a discussion of these methods to measure FMDBA, aPWV, and vascular endothelial cell protein expression. 相似文献
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目的:阿糖腺苷(Ara-A)是一种广谱抗病毒药物,临床上用于治疗多种病毒性疾病.同时也是合成阿糖腺苷单磷酸(Ara-AMP)的重要原料.本课题旨在寻找一种高效酶法生产嘌呤类阿糖核苷的方法.方法:以产气肠杆菌完整细胞为酶源,研究产气肠杆菌菌体培养条件对核苷磷酸化酶的影响及其诱导性.结果:胸苷磷酸化酶、尿苷磷酸化酶和嘌呤核苷磷酸化酶均可被多种核苷、核苷酸甚至碱基诱导.胞苷或胞苷酸的添加量为15-20mmol/L,诱导时间在0-8小时均可.经胞苷和胞苷酸诱导的菌体可使酶反应时间缩短6倍,大大提高了反应效率.经诱导的菌体,在反应后仍保持较高的核苷磷酸化酶活力;而未经诱导的菌体,一次反应后即丧失大量的酶活力.结论:核苷磷酸化酶的活性可以通过诱导而提高,以此优化阿糖腺苷的生产. 相似文献
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Senga Whittingham Ian R. Mackay R. S. Thanabalasundrum H. K. Chuttani R. Manjuran C. S. Seah M. Yu V. Viranuvatti 《BMJ (Clinical research ed.)》1973,4(5891):517-519
A total of 164 patients from Australia, Ceylon, India, Singapore, and Thailand were studied for the prevalence of autoantibodies associated with “idiopathic” chronic liver disease—namely, antinuclear antibody, smooth muscle antibody, and mitochondrial antibody. The prevalence of these autoantibodies was high among patients from Australia (55%), but was low among patients from Ceylon (14%), India (11%), Singapore (0%), and Thailand (8%). There are variations in types of hepatitis and cirrhosis between races, and this applies particularly to the type associated with autoimmune markers. This may be related to genetic differences that have evolved between peoples of European and Asian descent. 相似文献
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Yvonne Alt Anna Grimm Liesa Schlegel Annette Grambihler Jens M. Kittner J?rg Wiltink Peter R. Galle Marcus A. W?rns J?rn M. Schattenberg 《PloS one》2016,11(3)