ATP-binding cassette transporters in progression and clinical outcome of pancreatic cancer: what is the way forward?

Pancreatic ductal adenocarcinoma(PDAC) is one of the most aggressive diseases and is characterized by high chemoresistance, leading to the lack of effective therapeutic approaches and grim prognosis. Despite increasing understanding of the mechanisms of chemoresistance in cancer and the role of ATPbinding cassette(ABC) transporters in this resistance, the therapeutic potential of their pharmacological inhibition has not been successfully exploited yet. In spite of the discovery of potent pharmacological modulators of ABC transporters, the results obtained in clinical trials have been so far disappointing, with high toxicity levels impairing their successful administration to the patients. Critically, although ABC transporters have been mostly studied for their involvement in development of multidrug resistance(MDR), in recent years the contribution of ABC transporters to cancer initiation and progression has emerged as an important area of research, the understanding of which could significantly influence the development of more specific and efficient therapies. In this review, we explore the role of ABC transporters in the development and progression of malignancies, with focus on PDAC. Their established involvement in development of MDR will be also presented. Moreover, an emerging role for ABC transporters as prognostic tools for patients' survival will be discussed, demonstrating the therapeutic potential of ABC transporters in cancer therapy.

Inhibiting NF-κB increases cholesterol efflux from THP-1 derived-foam cells treated with AngⅡ via up-regulating the expression of ATP-binding cassette transporter A1

Objective： To study the role of nuclear factor-kappa B（NF- κB） in cholesterol efflux from THP-1 derived-foam cells treated with Angiotensin Ⅱ（Ang Ⅱ ）. Methods：Cultured THP-1 derived-foam cells were treated with Ang Ⅱ or preincubated with tosyl-phenylalanine chloromethyl-ketone（TPCK） NF- κB inhibitor. The levels of activated NF- κB in the cells were examined by sandwich ELISA, Cellular cholesterol content was studied by electron microscopy scanning and zymochemistry via fluorospectrophotometer and cholesterol effiux was detected by scintillation counting technique. ABCA1 mRNA and protein were quantified by RT-PCR and Western blotting. Results：Addition of TPCK to the cells before Ang Ⅱ stimulation attenuated the response of NF- κB p65 nuclear translocation induced by Ang Ⅱ and showed no peak in foam cells group and caused a reduction in cholesterol content and an increase in cholesterol efflux by 24.1%（P〈 0.05） and 41.1%（P〈 0.05） respectively, when compared with Ang Ⅱ group. In accordance, the ABCA1 mRNA and protein were increased by 30% and 19%（P 〈 0.05） respectively, when compared with Ang Ⅱ group. Conclusion：Ang Ⅱ can downregulate ABCA1 in THP-1 derived-foam cells via NF- K B, which leads to less cholesterol effiux and the increase of cholesterol content with the consequence of the promotion of atherosclerosis.

Novel understanding of ABC transporters ABCB1/MDR/P-glycoprotein, ABCC2/MRP2, and ABCG2/BCRP in colorectal pathophysiology

AIM: To evaluate ATP-binding cassette(ABC) transporters in colonic pathophysiology as they had recently been related to colorectal cancer(CRC) development. METHODS: Literature search was conducted on Pub Med using combinations of the following terms: ABC transporters, ATP binding cassette transporter proteins, inflammatory bowel disease, ulcerative, colitis, Crohns disease, colorectal cancer, colitis, intestinal inflammation, intestinal carcinogenesis, ABCB1/P-glycoprotein(P-gp/CD243/MDR1), ABCC2/multidrug resistance protein 2(MRP2) and ABCG2/breast cancer resistance protein(BCRP), Abcb1/Mdr1 a, abcc2/Mrp2, abcg2/Bcrp, knock-out mice, tight junction, membrane lipid function. RESULTS: Recently, human studies reported thatchanges in the levels of ABC transporters were early events in the adenoma-carcinoma sequence leading to CRC. A link between ABCB1, high fat diet and gut microbes in relation to colitis was suggested by the animal studies. The finding that colitis was preceded by altered gut bacterial composition suggests that deletion of Abcb1 leads to fundamental changes of hostmicrobiota interaction. Also, high fat diet increases the frequency and severity of colitis in specific pathogenfree Abcb1 KO mice. The Abcb1 KO mice might thus serve as a model in which diet/environmental factors and microbes may be controlled and investigated in relation to intestinal inflammation. Potential molecular mechanisms include defective transport of inflammatory mediators and/or phospholipid translocation from one side to the other of the cell membrane lipid bilayer by ABC transporters affecting inflammatory response and/or function of tight junctions, phagocytosis and vesicle trafficking. Also, diet and microbes give rise to molecules which are potential substrates for the ABC transporters and which may additionally affect ABC transporter function through nuclear receptors and transcriptional regulation. Another critical role of ABCB1 was suggested by the finding that ABCB1 expression identifies a subpopulation of pro-inflammatory Th17 cells which were resistant to treatment with glucocorticoids. The evidence for the involvement of ABCC2 and ABCG2 in colonic pathophysiology was weak. CONCLUSION: ABCB1, diet, and gut microbes mutually interact in colonic inflammation, a well-known risk factor for CRC. Further insight may be translated into preventive and treatment strategies.

High-density lipoprotein and atherosclerosis: Roles of lipid transporters

Various previous studies have found a negative cor-relation between the risk of cardiovascular events and serum high-density lipoprotein(HDL) cholesterol levels. The reverse cholesterol transport, a pathway of choles-terol from peripheral tissue to liver which has several potent antiatherogenic properties. For instance, the particles of HDL mediate to transport cholesterol from cells in arterial tissues, particularly from atherosclerotic plaques, to the liver. Both ATP-binding cassette trans-porters(ABC) A1 and ABCG1 are membrane cholesterol transporters and have been implicated in mediating cholesterol effluxes from cells in the presence of HDL and apolipoprotein A-I, a major protein constituent of HDL. Previous studies demonstrated that ABCA1 and ABCG1 or the interaction between ABCA1 and ABCG1 exerted antiatherosclerotic effects. As a therapeutic approach for increasing HDL cholesterol levels, much focus has been placed on increasing HDL cholesterol levels as well as enhancing HDL biochemical functions. HDL therapies that use injections of reconstituted HDL, apoA-I mimetics, or full-length apoA-I have shown dramatic effectiveness. In particular, a novel apoA-I mi-metic peptide, Fukuoka University ApoA-I Mimetic Pep-tide, effectively removes cholesterol via specific ABCA1 and other transporters, such as ABCG1, and has an an-tiatherosclerotic effect by enhancing the biological func-tions of HDL without changing circulating HDL choles-terol levels. Thus, HDL-targeting therapy has significant atheroprotective potential, as it uses lipid transporter-targeting agents, and may prove to be a therapeutic tool for atherosclerotic cardiovascular diseases.

Overexpression of the steroidogenic acute regulatory protein increases the expression of ATP-binding cassette transporters in microvascular endothelial cells(bEnd.3)

Objective:To determine the effect of steroidogenic acute regulatory protein(StAR) overexpression on the levels of adenosine triphosphate(ATP)-binding cassette transporter A1(ABCA1) and ATP-binding cassette transporter G1(ABCG1) in an endothelial cell line(bEnd.3).Methods:The StAR gene was induced in bEnd.3 cells with adenovirus infection.The infection efficiency was detected by fluorescence activated cell sorter(FACS) and fluorescence microscopy.The expressions of StAR gene and protein levels were detected by real-time polymerase chain reaction(PCR) and Western blot.The gene and protein levels of ABCA1 and ABCG1 were detected by real-time PCR and Western blot after StAR overexpression.Results:The result shows that StAR was successfully overexpressed in bEnd.3 cells by adenovirus infection.The mRNA and protein expressions of ABCA1 and ABCG1 were greatly increased by StAR overexpression in bEnd.3 cells.Conclusion:Overexpression of StAR increases ABCA1 and ABCG1 expressions in endothelial cells.

ATP-binding cassette transporter enhances tolerance to DDT in Tetrahymena

The reuse of dichlorodiphenyltrichloroethane(DDT) as an indoor residual spray was permitted by the World Health Organization in 2007, and approximately 14 countries still use DDT to control disease vectors. The extensive exposure of insects to DDT has resulted in the emergence of DDT resistance, especially in mosquitoes, and the mechanism for this resistance in mosquitoes has been widely reported. Spraying can also introduce DDT directly into surface water, and DDT can subsequently accumulate in microorganisms, but the mechanism for the resistance to DDT degradation in microorganisms is unclear. Using whole-genome microarray analysis, we detected an abcb15 gene that was up-regulated in a specific manner by DDT treatment in T. thermophile. The deduced ABCB15 peptide sequence had two transmembrane domains(TMDs) and two nucleotide-binding domains(NBDs) to form the structure TMD-NBD-TMD-NBD, and each NBD contained three conserved motifs: Walker-A, C-loop, and Walker-B, which indicated the T. thermophila abcb15 was a typical ABC transporter gene. The expression of ABCB15 fused with a C-terminal green fluorescent protein was found to be on the periphery of the cell, suggesting that ABCB15 was a membrane pump protein. In addition, cells with abcb15 partially knocked down(abcb15-KD) grew slower than wild-type cells in the presence of 256 mg L-1 DDT, indicating the tolerance of abcb15-KD strain to DDT exposure was decreased. Thus, we suggest that in Tetrahymena, the membrane pump protein encoded by ABCT gene abcb15 can enhance the tolerance to DDT and protect cells from this exogenous toxin by efficiently pumping it to the extracellular space.

ABC efflux transporters at blood-central nervous system barriers and their implications for treating spinal cord disorders

The barriers present in the interfaces between the blood and the central nervous system form a major hurdle for the pharmacological treatment of central nervous system injuries and diseases.The family of ATP-binding cassette(ABC)transporters has been widely studied regarding efflux of medications at blood-central nervous system barriers.These efflux transporters include P-glycoprotein(abcb1),‘breast cancer resistance protein'(abcg2)and the various‘multidrug resistance-associated proteins'(abccs).Understanding which efflux transporters are present at the blood-spinal cord,blood-cerebrospinal fluid and cerebrospinal fluid-spinal cord barriers is necessary to determine their involvement in limiting drug transfer from blood to the spinal cord tissue.Recent developments in the blood-brain barrier field have shown that barrier systems are dynamic and the profile of barrier defenses can alter due to conditions such as age,disease and environmental challenge.This means that a true understanding of ABC efflux transporter expression and localization should not be one static value but instead a range that represents the complex patient subpopulations that exist.In the present review,the blood-central nervous system barrier literature is discussed with a focus on the impact of ABC efflux transporters on:(i)protecting the spinal cord from adverse effects of systemically directed drugs,and(ii)limiting centrally directed drugs from accessing their active sites within the spinal cord.

Hepatocellular transport proteins and their role in liver disease

MOLECULAR PHYSIOLLGY OF HEPATOCELLULAR TRANSPORT PROTEINS Basolaferal transport systems Na+-dependent bile salt uptake Uptake of bile salts into the liver was first isolated perfused rat liver[1],isolated hepatocyte cultures and basolateral plasma membrane vesicles [2,4].

Drug-transporter interaction testing in drug discovery and development

The human body consists of several physiological barriers that express a number of membrane transporters. For an orally absorbed drug the intestinal, hepatic, renal and blood-brain barriers are of the greatest importance. The ATP-binding cassette(ABC) transporters that mediate cellular efflux and the solute carrier transporters that mostly mediate cellular uptake are the two superfamilies responsible for membrane transport of vast majority of drugs and drug metabolites. The total number of human transporters in the two superfamilies exceeds 400, and about 40-50 transporters have been characterized for drug transport. The latest Food and Drug Administration guidance focuses on P-glycoprotein, breast cancer resistance protein, organic anion transporting polypeptide 1B1(OATP1B1), OATP1B3, organic cation transporter 2(OCT2), and organic anion transporters 1(OAT1) and OAT3. The European Medicines Agency's shortlist additionally contains the bile salt export pump, OCT1, and the multidrug and toxin extrusion transporters, multidrug and toxin ex-trusion protein 1(MATE1) and MATE2/MATE2 K. A variety of transporter assays are available to test drugtransporter interactions, transporter-mediated drugdrug interactions, and transporter-mediated toxicity. The drug binding site of ABC transporters is accessible from the cytoplasm or the inner leaflet of the plasma membrane. Therefore, vesicular transport assays utilizing inside-out vesicles are commonly used assays, where the directionality of transport results in drugs being transported into the vesicle. Monolayer assays utilizing polarized cells expressing efflux transporters are the test systems suggested by regulatory agencies. However, in some monolayers, uptake transporters must be coexpressed with efflux transporters to assure detectable transport of low passive permeability drugs. For uptake transporters mediating cellular drug uptake, utilization of stable transfectants have been suggested. In vivo animal models complete the testing battery. Some issues, such as in vivo relevance, gender difference, age and ontogeny issues can only be addressed using in vivo models. Transporter specificity is provided by using knock-out or mutant models. Alternatively, chemical knock-outs can be employed. Compensatory changes are less likely when using chemical knockouts. On the other hand, specific inhibitors for some uptake transporters are not available, limiting the options to genetic knock-outs.

How to overcome ATP-binding cassette drug efflux transporter-mediated drug resistance?

P-glycoprotein(ABCB1),multidrug resistance protein-1(ABCC1)and breast cancer resistance protein(ABCG2)belong to the ATP-binding cassette(ABC)superfamily of proteins that play an important physiological role in protection of the body from toxic xenobiotics and endogenous metabolites.Beyond this,these transporters determine the toxicity profile of many drugs,and confer multidrug resistance(MDR)in cancer cells associated with a poor treatment outcome of cancer patients.It has long been hypothesized that inhibition of ABC drug efflux transporters will increase drug accumulation and thereby overcome MDR,but until now no approved inhibitor of these transporters is available in the clinic.In this review we present molecular strategies to overcome this type of drug resistance and discuss for each of these strategies their promising value or indicate underlying reasons for their limited success.

Efficacy of Shoushen granule on adenosine triphosphate binding cassette transporter A1, proprotein convertase subtilisin/kexin type 9 and toll-like receptor 4/nuclear factor kappa-B signaling pathway in ApoE-knockout mice

OBJECTIVE: To evaluate the efficacy of Shoushen granule, prepared with four Chinese medicinals, on the targeted regulation of adenosine triphosphate binding cassette transporter A1(ABCA1) through proprotein convertase subtilisin/kexin type 9(PCSK9) and toll-like receptor 4(TLR4)/nuclear factor kappa-B(NF-κB) signaling pathway to affect atherosclerosis(AS) in ApoE-knockout(ApoE-/-) mice.METHODS: ApoE-/-mice fed with a high-fat diet were used for AS modeling and divided into Model,Shoushen, and Atorvastatin groups. C57 BL/6 J mice at the same age and background strain were included in the Control group. Western blot and immunohistochemistry were used to measure ABCA1, PCSK9, TLR4, and NF-κB protein expression in mouse aortas. Enzyme-linked immuno sorbent assay was used to measure mouse serum tumor necrosis factor-α(TNF-α), interleukin-10(IL-10), monocyte chemoattractant protein 1(MCP-1), and intercellular cell adhesion molecule-1(ICAM-1) expression. Serum lipid profiles and histopathology were also assessed. Shoushen granule were composed of Heshouwu(Radix Polygoni Multiflori) 15 g, Gouqizi(Fructus Lycii) 15 g, Sheng shanzha(Raw Fructus Crataegus Pinnatifidae) 10 g, and Sanqi(Radix Notoginseng) 3 g.RESULTS: ApoE-/-mice fed with a high-fat diet had notable AS lesions, with reduced ABCA1 and IL-10 levels, elevated PCSK9, TLR4, NF-κB, TNF-α, MCP-1,and ICAM-1 expression, and increased total cholesterol(TC) and low density lipoprotein cholesterol(LDL-C) contents. With drug interventions, the areas of AS plaques were significantly reduced,the ABCA1 and IL-10 levels were increase, while the PCSK9, TLR4, NF-κB, TC, and LDL-C contents,and the TNF-α, MCP-1, and ICAM-1 expression were reduced.CONCLUSION: Shoushen granule effectively interfered with AS development by antagonizing the expression of key factors of the PCSK9 and TLR4/NF-κB signaling pathway to upregulate ABCA1 expression.

Roles of sulfonylurea receptor 1 and multidrug resistance protein 1 in modulating insulin secretion in human insulinoma

BACKGROUND:Sulfonylurea receptor 1(SUR1)and multidrug resistance protein 1(MRP1)are two prominent members of multidrug resistance proteins associated with insulin secretion. The aims of this study were to investigate their expression in insulinomas and their sole and synergistic effects in modulating abnormal insulin secretion. METHODS:Fasting glucose,insulin and C-peptide were measured in 11 insulinoma patients and 11 healthy controls. Prolonged oral glucose tolerance tests were performed in 6 insulinoma patients.Insulin content,SUR1 and MRP1 were detected in 11 insulinoma patients by immunohistochemistry. SUR1 and MRP1 were also detected in 6 insulinoma patients by immunofluorescence. RESULTS:Insulinoma patients presented the typical demons-trations of Whipple’s triad.Fasting glucose of each insulinoma patient was lower than 2.8 mmol/L,and simultaneous insulin and C-peptide were increased in insulinoma patients. Prolonged oral glucose tolerance tests showed that insulin secretion in insulinoma patients were also stimulated by high glucose.Immunohistochemistry and immunofluorescence staining showed that SUR1 increased,but MRP1 decreased in insulinoma compared with the adjacent islets. CONCLUSIONS:The hypersecretion of insulin in insulinomas might be,at least partially,due to the enrichment of SUR1. In contrast,MRP1,which is down-regulated in insulinomas, might reflect a negative feedback in insulin secretion.

Role of apolipoproteins,ABCA1 and LCAT in the biogenesis of normal and aberrant high density lipoproteins

In this review, we focus on the pathway of biogenesis of HDL, the essential role of apoA-I, ATP binding cassette transporter A1（ABCA1）, and lecithin： cholesterol acyltransferase（LCAT） in the formation of plasma HDL; the generation of aberrant forms of HDL containing mutant apoA-I forms and the role of apoA-IV and apoE in the formation of distinct HDL subpopulations. The biogenesis of HDL requires functional interactions of the ABCA1 with apoA-I（and to a lesser extent with apoE and apoA-IV） and subsequent interactions of the nascent HDL species thus formed with LCAT. Mutations in apoA-I, ABCA1 and LCAT either prevent or impair the formation of HDL and may also affect the functionality of the HDL species formed. Emphasis is placed on three categories of apoA-I mutations. The first category describes a unique bio-engineered apoA-I mutation that disrupts interactions between apoA-I and ABCA1 and generates aberrant prep HDL subpopulations that cannot be converted efficiently to a subpopulations by LCAT. The second category describes natural and bio-engineered apoA-I mutations that generate preβ and small size a4 HDL subpopulations, and are associated with low plasma HDL levels. These phenotypes can be corrected by excess LCAT. The third category describes bio-engineered apoA-I mutations that induce hypertriglyceridemia that can be corrected by excess lipoprotein lipase and also have defective maturation of HDL.The HDL phenotypes described here may serve in the future for diagnosis, prognoses and potential treatment of abnormalities that affect the biogenesis and functionality of HDL.

The classification of ATP-binding cassette subfamily A member 3 mutations using the cystic fibrosis transmembrane conductance regulator classification system

Importance: The ATP-binding cassette subfamily A member 3 (ABCA3) protein plays a vital role in surfactant homeostasis. Mutations in the ABCA3 gene lead to the development of interstitial lung disease. In the most severe manifestation, mutations can lead to a fatal respiratory distress syndrome in neonates. ABCA3 belongs to the same ATP-binding cassette transporter superfamily as the cystic fibrosis transmembrane conductance regulator (CFTR), the gene that causes cystic fibrosis. Objective: To classify ABCA3 mutations in a manner similar to CFTR mutations in order to take advantage of recent advances in therapeutics. Methods: Sequence homology between the CFTR protein and the ABCA3 protein was established. The region of CFTR that is a target for the new potentiator class of drugs was of particular interest. We performed a literature search to obtain all published mutations that were thought to be disease causing. We classified these mutations using the established CFTR classification system. When possible, we drew on previous experimental classification of ABCA3 mutations. Results: Although the proteins share the same overall structure, only a 19％identity was established between CFTR and ABCA3. The CFTR therapeutic target region has a 22％ homology with the corresponding ABCA3 region. Totally 233 unique protein mutations were identified. All protein mutations were classified and mapped to a schematic diagram of the ABCA3 protein. Interpretation: This new classification system for ABCA3, based on CFTR classification, will likely aid further research of clinical outcomes and identification of mutation-tailored therapeutics, with the aim for improving clinical care for patients with ABCA3 mutations.

A Possible Mechanism Linking Hyperglycemia and Reduced High-density Lipoprotein Cholesterol Levels in Diabetes

This study investigated the role of glucose in the biogenesis of high-density lipoprotein cholesterol(HDL-C).Mouse primary peritoneal macrophages were harvested and maintained in Dulbecco’s modified Eagle’s medium(DMEM) containing glucose of various concentrations.The cells were divided into 3 groups in terms of different glucose concentrations in the cultures:Control group(5.6 mmol/L glucose),high glucose concentration groups(16.7 mmol/L and 30 mmol/L glucose).ATP-binding cassette transporter A1(ABCA1) mRNA expression in the macrophages was detected by semi-quantitative RT-PCR 24,48 and 72 h after glucose treatment.The results showed that ABCA1 mRNA expression in the 16.7 mmol/L glucose group was not significantly different from that in the control group at all testing time points(P>0.05 for each).In the 30 mmol/L glucose group,macrophage ABCA1 mRNA expression was not changed significantly at 24 h(P=0.14),but was substantially decreased by 40.4% at 48 h(P=0.009) and by 48.1% at 72 h(P=0.015) as compared with that in the control group.It was concluded that ABCA1 is of vital importance for HDL-C biogenesis.High glucose may hamper HDL-C biogenesis by decreasing ABCA1 expression,which contributes to low HDL-C level in diabetes.

Some substrates of P-glycoprotein targeting <i>β</i>-amyloid clearance by quantitative structure-activity relationship (QSAR)/membrane-interaction (MI)-QSAR analysis

The pathogenesis of Alzheimer’s disease (AD) putatively involves a compromised blood-brain barrier (BBB). In particular, the importance of brain-to-blood transport of brain-derived metabolites across the BBB has gained increasing attention as a potential mechanism in the pathogenesis of neurodegenerative disorders such as AD, which is characterized by the aberrant polymerization and accumulation of specific misfolded proteins, particularly β-amyloid (Aβ), a neuropathological hallmark of AD. P-glycoprotein (P-gp), a major component of the BBB, plays a role in the etiology of AD through Aβ clearance from the brain. Our QSAR models on a series of purine-type and propafenone-type substrates of P-gp showed that the interaction between P-gp and its modulators depended on Molar Refractivity, LogP, and Shape Attribute of drugs it transports. Meanwhile, another model on BBB partitioning of some compounds revealed that BBB partitioning relied upon the polar surface area, LogP, Balaban Index, the strength of a molecule combined with the membrane-water complex, and the changeability of the structure of a solute-membrane-water complex. The predictive model on BBB partitioning contributes to the discovery of some molecules through BBB as potential AD therapeutic drugs. Moreover, the interaction model of P-gp and modulators for treatment of multidrug resistance (MDR) indicates the discovery of some molecules to increase Aβ clearance from the brain and reduce Aβ brain accumulation by regulating BBB P-gp in the early stages of AD. The mechanism provides a new insight into the therapeutic strategy for AD.

Protective Effect of Irbesartan on ATP Binding Cassette Transporter A1 in THP-1 Derived Macrophages

Objectives To explore the protective effect of irbesartan （lrb） under the interference with angiotensin II （Ang II） on ABCA1. Methods Electron microscopy was used to detect the morphous of foam cells. The expression of ABCA1 mRNA and its protein were determined by RT-PCR and Western blotting, respectively. The variance of cellular cholesterol content was measured by zymochemistry via-fluorospeetrophotometer. Results A positive facilitative effect of Ang II on the formation of foam cells was observed. Total cholesterol was increased significantly by Ang II, the expression of ABCA1 was down-regulated obviously by Ang II; Irb could protect ABCA1 against the lesion of Ang II; Total cellular cholesterol content was reduced significantly in Irb ＋ Ang II group; However, considerable alteration about the cholesterol content and the expression of ABCA1 were not observed in Irb group without incubation with Ang II. Conclusions Irb could protect ABCA1 against the lesion of Ang II, which may contribute to its anti-atherosclerotic properties. （ S Chin J Cardiol 2009; 10（4） ： 227 -233）

冠心病患者ABCG1、ANGPTL2启动子区甲基化与心力衰竭发生的关系研究

目的分析冠状动脉粥样硬化性心脏病(冠心病)患者三磷酸腺苷结合盒转运蛋白G1(ABCG1)、血管生成素样蛋白2(ANGPTL2)启动子区甲基化与心力衰竭(心衰)发生的关系。方法选取2020年3月至2022年3月于湖南省第二人民医院收治的冠心病患者120例。根据是否发生心衰,将患者分为合并心衰组(n=26)和不合并心衰组(n=94)。采用全自动生化仪检测血清总胆固醇(TC)、三酰甘油(TG)、低密度脂蛋白胆固醇(LDL-C)和高密度脂蛋白胆固醇(HDL-C)。采用心脏超声检查患者左室射血分数(LVEF)、左心室舒张末期内径(LVEDD)、左室收缩末期内径(LVESD)水平。特异性PCR检测ABCG1和ANGPTL2基因甲基化。采用实时荧光定量聚合酶链反应检测ABCG1和ANGPTL2基因mRNA表达水平。Logistic回归分析探讨影响冠心病患者发生心衰的因素。结果两组患者LDL-C、LVEF、LVEDD、LVESD、ABCG1、ANGPTL2基因启动子区甲基化等方面比较,差异具有统计学意义(P<0.05)。LVESD、LVEF、ABCG1甲基化和ANGPTL2甲基化是冠心病患者发生心衰的危险因素。ABCG1甲基化、ANGPLT2甲基化患者中LVESD水平均高于未甲基化患者(P<0.05)。ABCG1甲基化、ANGPLT2甲基化患者中LVEF水平均低于未甲基化患者(P<0.05)。合并组ABCG1、ANGPTL2基因甲基化的患者mRNA的表达量明显低于非甲基化患者(P<0.05)。结论ABCG1和ANGPTL2基因甲基化是冠心病患者发生心衰的危险因素,检测上述两基因甲基化状态可为诊治冠心病心衰提供理论支持。

辐射对药物转运体以及药物代谢动力学的影响

辐射是以波或粒子形式向周围扩散的能量,包含电离辐射与非电离辐射,可引发机体多种生理病理改变,近年来其对体内药物吸收代谢的影响备受关注。药物转运体是介导药物跨膜转运的关键,在药物代谢全程发挥重要作用,其水平可影响药物体内代谢,进而改变药物系统暴露量与毒性。关注辐射对机体药物转运体的影响对合理用药意义重大。本文着重综述不同类型辐射对药物转运体以及药物代谢动力学的影响。

1-苯基2-硫脲对Tg(abcb4:eGFP)斑马鱼肿瘤多重耐药相关基因表达的影响

目的探讨去色素药物1-苯基2-硫脲(PTU)对Tg(abcb4:eGFP)斑马鱼肿瘤多重耐药相关基因abcb4及其标记基因egfp表达的影响及可能机制。方法选取受精后24 h(24 hpf)Tg(abcb4:eGFP)斑马鱼胚胎做药物暴露实验,分为Control、PTU以及PTU+RES 3个组;持续用药96 h,通过荧光显微镜拍照检测各组斑马鱼胃肠道荧光强度;RT-qPCR检测abcb4、egfp及pxr基因mRNA,Western Blot检测abcb4、egfp蛋白(Abcb4、eGFP)的表达,罗丹明B积累实验检测不同组Abcb4功能。结果与Control组相比,PTU组Tg(abcb4:eGFP)斑马鱼荧光表达增强(P<0.01),PTU+RES组荧光变化不明显(P>0.05);PTU组abcb4、egfp及pxr基因mRNA表达均增加(P<0.005),PTU+RES组pxr基因mRNA表达增加(P<0.005),abcb4、egfp基因mRNA表达无明显变化(P>0.05);PTU组abcb4、egfp蛋白表达均增加(P<0.005),PTU+RES组无明显变化(P>0.05);PTU组Abcb4功能增强(P<0.01),PTU+RES组无明显变化(P>0.05)。结论PTU可诱导Tg(abcb4:eGFP)斑马鱼abcb4和egfp表达增加,核因子pxr可能参与PTU对abcb4和egfp的诱导调节过程,在应用PTU去色素处理的Tg(abcb4:eGFP)斑马鱼进行药物筛选时需注意PTU对abcb4和egfp表达的影响。