钠钾泵抑制剂通过调节细胞周期相关蛋白的生成介导肝癌HepG2细胞周期S期阻滞与凋亡

目的研究钠泵抑制剂哇巴因(ouabain)和华蟾毒配基(cinobufogenin)对人肝癌HepG2细胞增殖的抑制作用及细胞周期的改变,初步分析其机制。方法以人肝癌细胞HepG2为靶细胞,MTT比色法检测哇巴因和华蟾毒配基对HepG2细胞增殖的影响;Hoechst 33342荧光染色检测细胞形态学变化;流式细胞术检测细胞周期;实时定量PCR和Western blot检测CyclinA1、CDK2、PCNA和p21CIP1表达的变化。结果哇巴因和华蟾毒配基可明显抑制HepG2细胞增殖,抑制作用呈时间-浓度依赖性。荧光染色显示药物处理24h后,细胞呈现典型的凋亡形态特征;细胞周期分析显示,实验组S期细胞比例升高,实时定量PCR和Western blot结果显示:哇巴因和华蟾毒配基可下调CyclinA1、CDK2和PC-NA的表达(P<0.05),上调p21CIP1的表达(P<0.05)。结论钠泵抑制剂可抑制肝癌HepG2细胞的增殖,引起细胞周期S期阻滞,诱导细胞凋亡,这与其调节细胞周期相关蛋白的生成关系密切。     

蟾酥活性成分协调索拉非尼通过下调Akt/NF-κB信号途径抑制肝癌HepG2细胞生长

目的探讨蟾酥活性成分蟾蜍灵和华蟾毒配基协调索拉非尼抑制肝癌HepG2细胞生长的机制。方法 MTT法检测HepG2细胞经药物作用12、24、48 h后的增殖活性;Hoechst 33342荧光染色检测细胞形态学变化;流式细胞仪检测药物对HepG2细胞周期的影响;Western blot检测Akt、p-Akt(Ser473)、IκB、NF-κB、p-NF-κB p65、Bcl-2、Bax、cyclin A、PCNA蛋白表达水平。结果蟾蜍灵、华蟾毒配基和索拉非尼作用组均能抑制HepG 2细胞增殖,且药物联合作用组的增殖抑制率明显高于单独药物作用组,呈时间依赖性,用金氏公式得出在24 h具有协同作用(P<0.01);荧光染色结果显示,HepG 2细胞经药物处理24 h后,细胞呈现出核染色质凝集的凋亡形态特征;细胞周期检测结果显示,索拉非尼作用组使细胞周期阻滞于G0/G1期(P<0.01),蟾蜍灵、华蟾毒配基作用组使细胞周期阻滞于S期(P<0.01),药物联合作用组使细胞周期阻滞于S期(P<0.01);Western blot结果显示,蟾蜍灵、华蟾毒配基和索拉非尼单独药物作用组和联合作用组Akt、NF-κB总蛋白表达均无明显变化,p-Akt(Ser473)、p-NF-κB p65、Bcl-2、cyclin A、PCNA蛋白表达水平逐渐降低,联合作用组比单独药物作用组降低更为明显(P<0.01)。IκB、Bax蛋白表达水平逐渐升高,联合作用组比单独药物作用组升高更加明显(P<0.01)。结论蟾酥活性成分蟾蜍灵和华蟾毒配基协调索拉非尼通过下调Akt/NF-κB信号通路,抑制肝癌HepG 2细胞增殖。     

哇巴因和华蟾毒配基通过调节ERK信号通路诱导人肝癌HepG2细胞凋亡的研究

目的:通过检测钠钾泵(Na+/K+-ATPase)抑制剂哇巴因和华蟾毒配基对肿瘤细胞存活的影响,研究其通过调节ERK信号通路诱导肿瘤细胞凋亡的机制。方法:以人肝癌细胞HepG2为靶细胞,检测Na+/K+-ATPase的活性变化,Hochest33342荧光染色检测细胞形态学变化;单细胞电泳检测细胞DNA损伤程度,钙离子荧光探针检测Ca2+浓度变化;Westernblot检测Caspase-3、ERK的表达变化。结果:哇巴因和华蟾毒配基可抑制Na+/K+-ATPase的活性;可使HepG2细胞呈典型的凋亡形态特征;单细胞电泳显示其可损伤HepG2细胞DNA双链;Fluo-3AM检测显示哇巴因和华蟾毒配基促进了Ca2+浓度增高;Western blot显示其可促进Caspase-3的活化,上调ERK磷酸化水平。结论:Na+/K+-ATPase抑制剂可诱导肝癌HepG2细胞凋亡,导致细胞DNA损伤,诱导细胞内游离Ca2+浓度增高,促进细胞凋亡途径中主要蛋白Caspase-3的活化。而ERK信号通路在哇巴因和华蟾毒配基诱导的HepG2细胞凋亡过程中发挥着关键调控作用。     

酯蟾毒配基抑制人肝癌细胞体外增殖和迁移侵袭研究

本文旨在探讨酯蟾毒配基对人肝癌细胞增殖和迁移侵袭的影响及其相关机制。采用MTT比色法测定酯蟾毒配基对4种肝癌细胞的体外生长抑制作用,划痕实验和Transwell实验用来评估酯蟾毒配基对MHCC-97H细胞的迁移和侵袭能力,采用Western blot实验检测经不同浓度酯蟾毒配基处理后, MHCC-97H细胞内迁移侵袭相关蛋白的表达。结果表明,酯蟾毒配基能明显抑制肝癌细胞的体外增殖能力,其对MHCC-97H、HepG2、SK-Hep-1、Huh-7细胞的半数抑制浓度(half maximal inhibitory concentration, IC₅₀)值分别为0.55±0.06、2.83±0.24、5.25±0.49、14.89±2.28μmol·L^-1;酯蟾毒配基还能显著抑制MHCC-97H细胞的迁移和侵袭能力,且具有显著的浓度依赖性。MHCC-97H细胞中的整合素α2 (integrin α2)、整合素α6 (integrin α6)、整合素β1 (integrin β1)、N-钙黏蛋白(N-cadherin)、基质金属蛋白酶2 (mat...     

蟾皮中蟾毒配基类成分的分离与鉴定

目的研究中华大蟾蜍(Bufo bufo gargarizansCantor)皮中的蟾毒配基类成分。方法利用反复硅胶柱色谱、Sephadex LH-20凝胶柱色谱、半制备高效液相色谱、重结晶等手段分离纯化蟾皮中的蟾毒配基类成分,根据化合物的理化性质和各种波谱学数据鉴定其化学结构。结果分离得到11个蟾毒配基类化合物,分别鉴定为脂蟾毒配基(resibufogenin,1)、华蟾毒精(cinobufagin,2)、蟾毒灵(bufalin,3)、远华蟾毒精(telocinobufagin,4)、蟾毒它灵(bufotalin,5)、去乙酰华蟾毒它灵(desace-tylcinobufotalin,6)、嚏根草苷元(hellebrigenin,7)、沙蟾毒精(arenobufagin,8)、日蟾毒它灵(gam-abufotalin,9)、11β-羟基脂蟾毒配基(11β-hydroxylresibufogenin,10)、华蟾毒它灵(cinobufotalin,11)。结论化合物10和11为首次从中华大蟾蜍皮中分离得到。     

NBS1功能研究进展

NBS1基因突变可导致一种以染色质不稳定为特征的Nijmegen断裂综合征(NBS)。研究发现NBS1蛋白可与Mre11和Rad50蛋白形成一个Mre11-Rad50-NBS1复合物,在DNA的复制和DNA双链断裂的修复等过程中均起重要作用。本文对NBS1的结构及其在DNA的复制、维持染色质稳定以及DNA损伤应激反应中的作用进行综述。     

毒性中药蟾酥质量检测方法研究

目的:建立蟾蜍中多种药效及毒性成分蟾蜍毒素的定性定量检测方法。方法:采用液相色谱-质谱/质谱联用方法检测蟾酥中多种蟾蜍毒素成分。结果:建立了华蟾毒它灵、蟾蜍灵、华蟾毒配基及脂蟾毒配基的LC-MS/MS检测方法。比较了蟾酥样本的液相色谱-质谱/质谱联用分析数据。对4个不同来源中华大蟾蜍及黑眶蟾蜍的蟾酥样本进行检测,检出华蟾毒它灵、蟾蜍灵、华蟾毒配基及脂蟾毒配基的含量范围为0.05%~5.12%(w/w)。结论:液相色谱-质谱/质谱联用方法可用于蟾酥定性定量检测,并为质量评价提供参考。     

亚砷酸对HepG2肝癌细胞周期及P27、CyclinD1表达的影响

目的观察亚砷酸对HepG2肝癌细胞周期及P27、CyclinD1表达的影响,探讨亚砷酸对HepG2肝癌细胞周期影响的可能机制。方法采用免疫组织化学及流式细胞检测方法研究了亚砷酸对HepG2肝癌细胞周期及P27、CyclinD1表达的影响。结果空白对照组、低剂量亚砷酸组(1.0mg/L)、中剂量亚砷酸组(1.5mg/L)、高剂量亚砷酸组(2.0mg/L)P27阳性细胞所占百分比分别为(22.80±6.94)、(25.60±7.41)、(28.00±5.21)、(31.20±4.98),低剂量组与空白对照组比较P<0.05,中、高剂量组与空白对照组比较P<0.01。空白对照组、低剂量亚砷酸组(1.0mg/L)、中剂量亚砷酸组(1.5mg/L)、高剂量亚砷酸组(2.0mg/L)CyclinD1阳性细胞所占百分比分别为(38.40±5.68)、(24.70±8.98)、(18.90±6.51)、(15.20±8.44),与空白对照组比较P<0.01。空白对照组、低剂量亚砷酸组(1.0mg/L)、中剂量亚砷酸组(1.5mg/L)、高剂量亚砷酸组(2.0mg/L)G1期细胞所占百分比分别为66.5%、70.6%、73.4%、77.5%。结论亚砷酸可影响HepG2人肝癌细胞周期,其机制可能是通过降低CyclinD1水平,上调P27蛋白水平而作用于G1-S限制点,使HepG2细胞不能通过G1-S限制点使其阻滞于G1期不能增殖。     

蟾酥中强心甾类化学成分的分离与鉴定

目的对蟾酥的氯仿提取物进行化学成分的分离与鉴定。方法以3倍量氯仿索氏提取,采用硅胶柱色谱、凝胶柱色谱、高效液相色谱等手段对氯仿提取物进行分离纯化,根据其理化性质和波谱数据(1H-NMR、13C-NMR)进行结构鉴定。结果从蟾酥的氯仿提取物中分离得到6个强心甾类化合物,经光谱数据分析,鉴定其结构分别为脂蟾毒配基(resibufagenin,1)、华蟾毒精(cinobufagin,2)、蟾毒灵(bufalin,3)、华蟾毒它灵(cinobufatalin,4)、12 β-羟基华蟾毒精(12 β-hydroxylcinobufagin,5)、1β-羟基华蟾毒精(1β-hydroxylcinobufagin,6)。结论化合物6为一新的天然产物。     

华蟾酥毒基和酯蟾毒配基与不同血浆蛋白结合率的测定

建立测定华蟾酥毒基和酯蟾毒配基与人、比格犬和大鼠血浆蛋白结合率的方法;采用平衡透析法,并以高效液相色谱法进行测定,计算华蟾酥毒基和酯蟾毒配基与不同血浆的蛋白结合率。华蟾酥毒基和酯蟾毒配基在3种不同透析内液中的线性范围均为0.50～40.00μg.mL 1,透析外液均为0.25～4.00μg.mL 1。在3种不同透析内液和透析外液中,华蟾酥毒基提取回收率为(68.73±2.16)%～(79.27±1.62)%,酯蟾毒配基为(71.59±4.31)%～(83.47±2.63)%。华蟾酥毒基在人、大鼠和比格犬血浆中的平均血浆蛋白结合率分别为85.63%、80.21%和70.10%,酯蟾毒配基分别为84.51%、75.11%和70.60%。结果表明,华蟾酥毒基和酯蟾毒配基与3种血浆蛋白结合率较高,且结合率人>大鼠>比格犬。     

Cerebral metabolism of [3H]-p-chloroamphetamine

The time-dependent metabolism of intraventricularly administered $\text{[}{}^3\text{H}\text{]-p-}\text{chloroamphetamine}$ was followed. The parent compound and its metabolites were recovered by high pressure liquid chromatography and characterized by high pressure liquid chromatography, thin-layer chromatography, and gas chromatography-mass spectrometry. By 4 hr after injection, two major toluene-soluble metabolites were present in brain. Their biological half-lives were different from the parent compound. On the basis of their analyses, one of the metabolites is p-chloronorephedrine, the other (P₃) is as yet unidentified. Pretreatment with Lilly 110140 prevented or markedly reduced the synthesis of both p-chloronorephedrine and P₃. Iprindole prevented the synthesis of p-chloronorephedrine. The P₃ appeared first in the brain then in the liver, suggesting that both of these organs can metabolize p-chloroamphetamine to this compound. The metabolites were recovered primarily from the nuclear and microsomal fractions following subcellular fractionation of the brain, with small quantities present in the synaptosomal fraction. The level of metabolites was higher in the brainstem than in the neocortex. Glutathione, administered simultaneously with p-chloroamphetamine either intraventricularly or intraperitoneally failed to alter the toxicity of p-chloroamphetamine.     

Clevudine University of Georgia/Abbott/Bukwang/Triangle/Yale University

The pyrimidine analog, clevudine (L-FMAU: 2'-fluoro-5-methyl-beta-L-arabinofuranosyluridine) is a potent antihepatitis B virus (HBV) and anti-Epstein-Barr virus (EBV) agent, discovered by researchers at the University of Georgia, in collaboration with Yale University and Bukwang. Bukwang transferred its technology to Triangle Pharmaceuticals in 1998 together with a license to develop clevudine worldwide except Korea [279649], [281942]. In June 1999, Triangle and Abbott Laboratories entered into a strategic alliance to copromote antiviral products including L-FMAU [326798]. In September 2000, Triangle Pharmaceuticals Inc initiated a 30-day phase I/II evaluation of clevudine in HBV-infected patients [381755]. Clevudine is a much less toxic derivative of the toxic agent P-D-FMAU. The mechanism of action of clevudine is not yet clear, but the agent induces a rapid decrease in HBV nucleic acid as doses increase from 0.3 to 10 mg/kg [319145]. It is believed that the target for clevudine lies in the viral replication mechanism. Clevudine is phosphorylated to the triphosphate form intracellularly. This is removed slowly from the cells, thus exerting a sustained inhibitory antiviral activity [178173], [320720], [320721].     

Spotlight from the American Society for Preventive Cardiology on Key Features of the 2018 AHA/ACC/AACVPR/AAPA/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA Guidelines on the Management of Blood Cholesterol

The 2018 AHA/ACC/AACVPR/AAPA/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA Guideline on the Management of Blood Cholesterol retains focus on recommendations for statin treatment in the original four statin-eligible groups [those with atherosclerotic cardiovascular disease (ASCVD), diabetes, low-density lipoprotein cholesterol (LDL-C) ≥ 190 mg/dL, and higher risk primary prevention] without the use of treatment initiation or target LDL-C levels from the earlier 2013 American College of Cardiology/American Heart Association (ACC/AHA) guideline, but has several new features. First, patients with primary prevention are divided into those who are at low (< 5%), borderline (5% to < 7.5%), intermediate (7.5% to < 20%), and high (≥ 20%) risk based on the ASCVD risk estimator. Moreover, the new guideline goes further to consider a wider range of factors [now called “risk enhancers”—premature family history of ASCVD, persistently high LDL-C, chronic kidney disease (CKD), metabolic syndrome, conditions specific to women, inflammatory diseases, and high-risk ethnicities] that can be used to better inform the treatment decision. Moreover, more detailed recommendations on how the results of coronary calcium scanning can be used to inform the treatment decision are provided, including how it may be used to “de-risk” certain patients for delaying or avoiding the use of statin therapy. There are also specific sections for cholesterol management in other patient subgroups including women, children, certain ethnic groups, those with CKD, chronic inflammatory disorders and HIV, as well as discussion on the management of hypertriglyceridemia. Importantly, for persons with known ASCVD, a distinction is made for those who are at “very high risk” based on having had two major ASCVD events or one major event and two or more other high risk conditions, such as diabetes or other major risk factors, or bypass surgery or percutaneous intervention. Finally, the concept of a threshold LDL-C for initiating a non-statin therapy (after considering highest tolerated statin dosage) is provided, with ezetimibe recommended as the key non-statin to be added if the LDL-C still remains ≥ 70 mg/dL for all ASCVD patients, and in those who are at “very high risk”, further consideration for using a proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor. While the new guideline does have greater detail (and arguably, complexity), the refinements provide a strategy for guiding the clinician to target both statin and non-statin therapy to those most likely to derive benefit.     

Pitavastatin Nissan/Kowa Yakuhin/Novartis/Sankyo

Pitavastatin (nisvastatin) is an HMG CoA reductase inhibitor being developed jointly by Nissan, Kowa Kogyo, Novartis and Sankyo for the potential treatment of atherosclerosis and hyperlipidemia.     

Amlodipine/Valsartan/Hydrochlorothiazide

Amlodipine/valsartan/hydrochlorothiazide (HCTZ) is a fixed-dose combination of the well established antihypertensive agents amlodipine (a calcium channel antagonist), valsartan (an angiotensin II receptor antagonist), and HCTZ (a thiazide diuretic). In patients with moderate or severe hypertension, triple combination therapy with amlodipine + valsartan + HCTZ produced significantly greater reductions from baseline in mean sitting systolic and diastolic BP (msSBP and msDBP) than either valsartan + HCTZ, amlodipine + HCTZ, or amlodipine + valsartan in a large, 8-week, randomized, double-blind, multinational, phase III trial. Furthermore, the proportion of patients achieving overall BP control at endpoint was significantly greater with the triple combination regimen than with any of the dual regimens, with significantly more triple combination recipients achieving msSBP and msDBP control at each assessment throughout the trial. Subgroup analyses of this study suggested that amlodipine + valsartan + HCTZ was generally more effective in reducing BP and providing overall BP control than the dual combination therapies, irrespective of age, race, gender, ethnicity, or hypertension severity. Several smaller studies provide data that support the efficacy of amlodipine + valsartan + HCTZ in patients whose BP is inadequately controlled with amlodipine + valsartan, amlodipine + HCTZ, or valsartan + HCTZ dual combination therapy. Treatment with amlodipine + valsartan + HCTZ for up to 8 weeks was generally well tolerated in the large, phase III trial, with most adverse events being transient and of mild to moderate severity.     

N-Nitroso-N-Methyldodecylamine and N-Nitroso-N-Methyltetradecylamine in household dishwashing liquids

Eleven household dishwashing liquids and four household surface cleaners were analysed for N-nitroso-N-methyldodecylamine and N-nitroso-N-methyltetradecylamine by gas chromatography with detection using a Thermal Energy Analyzer. Both nitrosamines were found in three of the dishwashing detergents and one of the surface cleaners. [1-¹⁴C]-N-Nitroso-N-methyldodecylamine was used to determine recoveries, which were between 65 and 88%. Levels of N-nitroso-N-methyldodecylamine ranged from 112 to 661 ppb and those of N-nitroso-N-methyltetradecylamine from 46 to 151 ppb. A simple method was developed to screen the products for N,N-dimethyldodecylamine-N-oxide, a surfactant ingredient suspected of being the source of these nitrosamines. By application of this method it was established that all of the products formulated with this amine oxide contained these two nitrosamines, whereas in products that did not contain this ingredient, these nitrosamines were not detected.     

PROTON AND POTASSIUM TRANSPORT BY H+/K+-ATPases

1. H⁺/K⁺-ATPases are members of the P-type ATPase multigene family. The prototypical H⁺/K⁺-ATPase is the protein that acidifies gastric luminal contents. The physiological and pharmacological significance of this pump has led to a detailed investigation of its biochemistry and molecular and cell biology. 2. Recently, a number of closely related H⁺/K⁺-ATPase isoforms have been discovered. These isoforms are present in organs other than the stomach, including the colon and kidney, where they contribute to acid—base and potassium homeostasis. The structure, expression and physiological roles of the gastric H⁺/K⁺-ATPase and other isoforms are reviewed.     

INTERACTIONS OF Na+, H2O2 AND THE Na+-Ca2+ EXCHANGER STIMULATE Ca2+ RELEASE IN CK1.4 CELLS

1. The present study aimed to demonstrate that interactions of cations, hydrogen peroxide (H₂O₂) and the Na⁺-Ca²⁺exchanger stimulate Ca²⁺ release and oscillations of cytosolic Ca²⁺ [Ca²⁺]i in non-transfected Chinese Hamster Ovary (CHO) C1 cells and in transfected CHO (CK1.4) cells that contained an expression vector coding the Na⁺-Ca²⁺ exchanger sequence. 2. The [⁴⁵Ca²⁺] uptake assay, fura-2 fluorescence imaging and 2² and 2³ factorial orthogonal statistics provide comparative, direct, efficient, quantitative and transient methods to delineate the effects of such interactions on Ca²⁺ influx, Ca²⁺release and [Ca²⁺]i in C1 and CK1.4 cells. 3. In contrast to the control of either Na⁺-, Ca²⁺- or H₂O₂-free or CI cells, an elevated [⁴⁵Ca²⁺] uptake was induced by Ca²⁺, Na⁺ and H₂O₂ individually and in combination, intracellular Ca²⁺ release was activated by H₂O₂ and by combinations of either H₂O₂ and Na⁺, H₂O₂ and the Na⁺-Ca²⁺ exchanger, Na⁺ and the Na⁺-Ca²⁺ exchanger or by H₂O₂, Na⁺ and the Na⁺-Ca²⁺ exchanger and a rise in [Ca²⁺]i was triggered by H₂O₂, Na⁺ and a combination of Na⁺ and the Na⁺-Ca²⁺exchanger. 4. These results indicate that interactions between H₂O₂, Na⁺ and the Na⁺-Ca²⁺ exchanger stimulate intracellular Ca²⁺mobilization via Ca²⁺-induced Ca²⁺ release mechanisms, ATP-activated G-protein coupled P_2y-purinoceptor-sensitive pathways, Na⁺-Ca²⁺ exchanger-mediated Ca²⁺ influx and cation-π interaction (a strong non-covalent force between the cation and the π face of an aromatic structure in the transmembrane protein). 5. The present findings provide important clues for understanding Ca²⁺ signal transduction mechanisms from the plasma membrane to the endoplasmic reticulum.     

EFFECTS OF THE OPIOID PEPTIDES [MET5]ENKEPHALIN-ARG6-PHE7 AND [MET5]ENKEPHALIN-ARG6-GLY7-LEU8 ON CHOLINERGIC NEUROTRANSMISSION IN THE RABBIT ISOLATED ATRIA

1. The effect of the opioid peptides [Met5]enkephalin-Arg6-Phe7 (MEAP) and [Met5]enkephalin-Arg6-Gly7-Leu8 (MEAGL) were compared with those of [Leu5]enkephalin and [D-Ala2,Met5]enkephalinamide (DAME) on cholinergic neurotransmission in the rabbit isolated atria. 2. Rabbit isolated atria had a resting rate of 190 beats/min. In the presence of the beta-adrenoceptor antagonist propranolol (0.3 mumol/l), atria responded to electrical field stimulation with a cholinergically mediated negative chronotropic response. The opioid peptides had no effect on the resting rate, but inhibited the negative chronotropic response to field stimulation. The IC50 values for inhibiting the cholinergic responses were 1.4 mumol/l for [Leu5]enkephalin (LE), 1.4 mumol/l for MEAP, 1.3 mumol/l for MEAGL and 0.2 mumol/l for DAME. Responses of a similar magnitude to exogenous acetylcholine were unaffected. 3. Thus, MEAP, MEAGL and LE had similar potencies but DAME was about seven times more potent in inhibiting cholinergic neurotransmission in the rabbit isolated atria. The site of inhibition appears to be prejunctional.