白花蛇舌草乙醇提取物体外诱导人AML-M2白血病细胞凋亡机制研究

目的 观察白花蛇舌草乙醇提取物对AML-M2白血病Kasumi-1细胞增殖和凋亡的影响机制。方法 采用MTT比色法、Hoechest荧光染色检测测定白花蛇舌草乙醇提取物作用后Kasumi-1细胞增殖和凋亡的情况,Western blot法检测Kasumi-1细胞中Bcl-2、Bax、Caspase-3、Caspase-9、Cyto-C、P65、p-P65、IkBα、p-IkBα、IKKα/β、C-MYC以及AML1-ETO的蛋白水平。结果 白花蛇舌草乙醇提取物抑制急性髓系白血病Kasumi-1细胞增殖(P＜0.05),并具有时间和浓度依赖性。0.02、0.04、0.06、0.08mg/ml的白花蛇舌草乙醇提取物能诱导细胞凋亡(P＜0.05),EEHDW可以显著上调Cyto-C、cleaved PARP、cleaved Caspase-3、9以及Bax的表达水平,而降低Bcl-2、C-MYC和AML1-ETO蛋白的表达,同时EEHDW能够浓度依赖性的激活NF-кB信号通路。结论 白花蛇舌草乙醇提取物诱导Kasumi-1细胞凋亡一方面是通过调节BAX/ BCL-2的表达影响线粒体途径,另外一方面还与激活NF-кB信号通路有关,在这个过程中同时抑制原癌基因c-myc和AML1-ETO融合基因的表达。     

菊苣酸诱导人白血病细胞HL-60凋亡作用及机制研究

目的观察菊苣酸诱导人急性髓系白血病细胞株HL-60凋亡的作用并初步探讨其机制。方法培养HL-60细胞,分别给予终浓度为10¹00μmol·L-1的菊苣酸48 h,检测细胞活性和凋亡、Caspase-3活性以及Bcl-2蛋白表达水平。结果终浓度为10100μmol·L-1的菊苣酸48 h,检测细胞活性和凋亡、Caspase-3活性以及Bcl-2蛋白表达水平。结果终浓度为10¹00μmol·L-1的菊苣酸能呈浓度依赖性降低HL-60细胞增殖活性和增加凋亡,增强Caspase-3活性和下调Bcl-2蛋白表达。结论菊苣酸具有抑制白血病细胞株HL-60增殖活性和诱导其凋亡作用,其机制与降低抗凋亡蛋白Bcl-2表达及增强Caspase-3活性有关。     

丙戊酸钠抑制Kasumi-1细胞增殖及诱导分化和凋亡机制的研究

目的:探讨丙戊酸钠(VPA)通过抑制组蛋白脱乙酰化酶(HDAC)的活性,消除AML1-ETO融合蛋白转录抑制作用,抑制Kasumi-1细胞增殖及诱导凋亡的机制。方法:不同浓度VPA处理Kasumi-1细胞不同时间后,应用台盼蓝拒染人工计数法观察VPA对细胞增殖的影响,普通光学显微镜观察细胞形态改变,流式细胞术分析细胞周期和检测髓系分化抗原CD11b的表达水平的变化,DNA凝胶电泳检测细胞的凋亡。结果:VPA能显著抑制Kasumi-1细胞的增殖,且呈剂量和时间依赖性,VPA处理Kasumi-1细胞72h时的半数抑制浓度(IC50)为2.33mmol/L;VPA处理后,细胞周期检测G0/G1期细胞比例逐渐增高;VPA能诱导髓系分化抗原CD11b表达水平的阳性率升高,呈时间及剂量依赖性;VPA能诱导Kasumi-1细胞凋亡,Kasumi-l细胞经VPA3mmol/L处理72h后,出现典型的凋亡细胞所具有的梯形DNA条带。结论:VPA能抑制Kasumi-1细胞增殖,阻滞细胞周期于G0/G1期,诱导细胞部分分化和凋亡。     

MDR-1与GST-π在柔红霉素诱导Kasumi-1细胞耐药中的作用

目的探讨柔红霉素诱导M2型急性髓系白血病(AML-M2)细胞株Kasumi-1耐药性与多药耐药基因-1(MDR-1)和谷胱甘肽S转移酶-π(GST-π)表达的相关性。方法长期间歇性小剂量递增法诱导Kasumi-1对柔红霉素耐药,四氮唑蓝(MTT)法检测细胞耐药程度;实时定量聚合酶链反应(RT-PCR)检测MDR-1和GST-π基因表达变化情况;Western blot检测P-糖蛋白(P-gp)和GST-π蛋白表达的变化情况。结果诱导后Kasumi-1对柔红霉素耐药倍数为(3.9±0.6)倍,耐药细胞与非耐药细胞MDR-1表达无明显差别,耐药细胞GST-π表达明显高于非耐药细胞(P<0.01)。Western blot检测结果与RT-RCR一致,两种细胞P-gp表达情况无明显差异,耐药株GST-π蛋白表达明显升高(P<0.01)。结论 AML-M2细胞株Kasumi-1对柔红霉素耐药与MDR-1表达无关,与GST-π表达有关,抑制GST-π在Kasumi-1细胞中的表达可能成为逆转柔红霉素耐药的靶点。     

新型化合物XN4抑制急性粒细胞白血病细胞增殖与其诱导氧化性的DNA损伤的关系

目的研究XN4在体外抑制急性粒细胞白血病细胞(AML)增殖的作用与诱导DNA损伤的关系。方法 MTT法检测XN4对AML细胞增殖抑制作用;流式细胞术检测AML细胞反应性氧自由基(ROS)、DNA损伤、细胞周期和细胞凋亡;Western blot探讨XN4对相关蛋白表达的影响。结果 XN4明显抑制AML细胞增殖,半数抑制率(IC50)分别为(2.79±0.15)μmol·L-1和(2.76±0.20)μmol·L-1;XN4增加细胞ROS水平和r-H2AX的表达,诱导细胞阻滞在S期并增加细胞凋亡率;XN4能增加H2AX、ATM的磷酸化以及Parp和Caspase-3的切割,而减少CDK2和Cyclin E1的表达。结论 XN4通过激活ROS,诱导DNA的损伤和细胞周期S期阻滞,抑制DNA损伤修复和诱导细胞的凋亡,抑制HL-60及KG1α细胞的增殖,抗氧化剂NAC(N-乙酰半胱氨酸)能减少ROS的产生逆转XN4的作用。     

三氧化二砷诱导K562细胞凋亡过程中血管内皮因子的变化

目的 通过观察三氧化二砷(As2O3)对人类慢性髓系白血病(CML)细胞株K562细胞的作用.探讨其治疗CML的作用机制.方法 将K562细胞与不同浓度As2O3共同孵育,于24、48、72 h用MTT方法检测K562细胞存活率,用AnnexinV-FITC检测凋亡细胞,同时用酶联免疫吸附法(ELISA)检测K562细胞上清液中血管内皮因子(VEGF)的浓度.结果 As2O3＜2 μmol·L-1时,对K562细胞增殖抑制和诱导凋亡的作用与空白对照组比较,无统计学意义(P＞0.05);As2O3＞2 μmol·L-1时则具统计学意义(P＜0.05);在相同作用时间下,AS2O3 浓度升高对K562细胞的增殖抑制率及细胞凋亡率亦升高;当As2O3＞8 μmol·L-1时,对K562细胞的抑制及细胞凋亡率不再上升. As2O3＜2 μmol·L-1时上清液中VEGF浓度与空白对照组比较无显著性(P＞0.05);As2O3＞2 μmol·L-1时VEGF的浓度差异有显著性(P＜0.05),且随As2O3 浓度的增加VEGF浓度上升;当As2O3＞8 μmol·L-1时则变化不显著(P＞0.05).结论 As2O3可抑制K562细胞增殖,并具诱导凋亡作用, As2O3在2.0～10.0 μmol·L-1梯度浓度,作用在24～72 h时段,表现为时间和剂量依赖性,还可下调VEGF表达水平.     

PEITC 诱导人 AML-M2白血病细胞凋亡机制的初步探讨

目的：证实苯乙基异硫氰酸酯（phenethyl isothiocyanate ,PEITC）诱导人急性髓系白血病（AML） M2白血病细胞系Kasumi‐1细胞凋亡的效应,初步探讨PEITC诱导Kasumi‐1细胞凋亡的机制。方法培养人M2白血病细胞株Kasumi‐1细胞,CCK‐8法检测不同浓度 PEITC处理后Ka‐sumi‐1细胞的增殖抑制率;流式细胞术检测药物诱导细胞凋亡和活性氧（reactive oxygen species , ROS）生成的情况;Real‐time PCR及Western blot检测 HO‐1以及凋亡相关基因caspase3、caspase8、caspase9 mRNA及蛋白水平的变化。结果 CCK‐8结果显示PEITC作用Kasumi‐1细胞24 h、48 h、72 h后,细胞增殖抑制率呈现浓度－时间依赖性。流式细胞术显示 PEITC能够诱导Kasumi‐1细胞的凋亡。Real‐time PCR及Western blot结果显示PEITC处理细胞后,HO‐1表达下降,而凋亡相关基因Caspase3、Caspase8、Caspase9的表达上调。DCFH‐DA探针法显示 PEITC作用Kasumi‐1细胞后,ROS生成增多。结论 PEITC能够促进Kasumi‐1细胞凋亡,呈时间剂量梯度依赖关系;PEITC诱导Kasumi‐1细胞凋亡可能通过的机制包括下调 HO‐1表达促进 ROS 生成及凋亡相关基因Caspase3、Caspase8、Caspase9的激活。     

蛋白酶体抑制剂MG132对急性髓系白血病细胞增殖与凋亡的影响

目的探讨蛋白酶体抑制剂MG132对急性髓系白血病(acute myeloid leukemia,AML)细胞增殖与凋亡的影响。方法 qRT-PCR检测9株血液肿瘤细胞株内ADRM1 mRNA表达。利用shRNA干扰HL60细胞内ADRM1表达,将不同浓度的MG132作用于ADRM1干扰前后的HL60细胞24 h,CCK-8法检测各组细胞增殖与活力;Western blot检测各组细胞内ADRM1、UCH37蛋白表达;流式细胞仪分析不同浓度MG132作用下,HL60、NB4细胞凋亡情况。结果血液肿瘤细胞株内ADRM1 mRNA表达上调。成功构建ADRM1 shRNA与scrambled shRNA HL60细胞株。ADRM1基因干扰及给予MG132后,各实验组细胞增殖抑制,活力下降,此时细胞内ADRM1、UCH37蛋白表达下调。随着MG132浓度提高,HL60、NB4细胞凋亡增加;MG132对HL60细胞的促凋亡作用强于NB4细胞。结论血液肿瘤细胞株内ADRM1 mRNA过表达;ADRM1蛋白下调后,UCH37蛋白亦下调,细胞增殖抑制;MG132通过下调ADRM1、UCH37蛋白表达,诱导AML细胞凋亡,抑制细胞增殖与活力;MG132对不同分型AML细胞的促凋亡作用存在个体差异。     

大蒜素抗白血病作用的研究

目的研究大蒜素(allicin)对急性髓系白血病(AML)患者骨髓单个核细胞(BMMNC)的作用并探讨其机制。方法采用大蒜素在体外作用于AML患者BMMNC,经MTT法、TdT缺口末端标记(TUNEL)技术、RT-PCR等方法检测大蒜素对AML患者BMMNC的影响。结果不同浓度大蒜素对AML患者BMMNC有不同程度的生长抑制、诱导凋亡和抑制iNOSmRNA表达的作用。①MTT法检测大蒜素对细胞的增殖抑制作用,发现大蒜素在3个浓度范围内对细胞均有增殖抑制作用,并呈量效关系。②TUNEL检测见阳性细胞核深染,大蒜素处理组与对照组比较,凋亡细胞明显增多。③RT-PCR检测发现大蒜素能显著抑制iNOSmRNA表达。结论大蒜素可抑制AML患者BMMNC生长、诱导期凋亡及抑制iNOSmRNA表达。     

DLK1及c-FLIP基因在AML中的表达

目的 探讨急性髓细胞白血病(AML)患者c-FLIPL、c-FLIPS及DLKl基因的表达水平及临床意义.方法 应用逆转录-PCR半定量检测8例AML(AML组)及3例非恶性血液病患者(对照组)骨髓单个核细胞中c-FLIPL、c-FLIPS及DLKl mRNA的表达水平.结果 AML组患者DLKl mRNA、c-FLIPL mRNA、c-FLIPS mRNA表达均明显高于对照组(P＜0.05),且AML各FAB亚型间差异无统计学意义(P＞0.05).结论 DLKl、c-FLIPL及c-FLIPS基因在AML患者中表达异常增高,可能在白血病细胞逃脱凋亡、无限增殖中发挥作用.     

Sulfation of iodothyronines by human sulfotransferase 1C1 (SULT1C1)*

Sulfation is an important component of human thyroid hormone metabolism. The role of the human sulfotransferase 1C1 (SULT1C1) is not known. Because SULT1C1 is present in the adult thyroid, intra-thyroidal sulfation of thyroid hormones and their metabolites might occur. We tested this hypothesis by determining the ability of recombinant human SULT1C1 to catalyze iodothyronine sulfation. Apparent K(m) values for 3,3',5-triiodothyronine (T(3)), 3, 3'-diiodothyronine (3,3'-T(2)), 3',5',3-triiodothyronine (rT(3)), and 3,3',5,5'-tetraiodothyronine (T(4)) with SULT1C1 were 28.7, 10.3, 10.2, and 59.3 microM, respectively. Thermal stability and responses to inhibitors also were tested with T(3) as the substrate. Enzyme aliquots were measured simultaneously to determine SULT1C1 substrate preferences at optimal iodothyronine concentrations. SULT1C1 activity obtained with T(3) was used as 100%, and the activities with 3,3'-T(2), rT(3), T(4), and 3,5-diiodothyronine (3, 5-T(2)) were 614, 314, 25, and 4%, respectively. We report for the first time the characterization of human SULT1C1 with T(3) and the preferences of the enzyme for various iodothyronines. The presence of SULT1C1 in the adult thyroid gland raises the possibilities that the enzyme can contribute to intraglandular thyroid hormone processing and iodide reutilization.     

Phenotype of the Cyp1a1/1a2/1b1-/- triple-knockout mouse

Crossing the Cyp1a1/1a2(-/-) double-knockout mouse with the Cyp1b1(-/-) single-knockout mouse, we generated the Cyp1a1/1a2/1b1(-/-) triple-knockout mouse. In this triple-knockout mouse, statistically significant phenotypes (with incomplete penetrance) included slower weight gain and greater risk of embryolethality before gestational day 11, hydrocephalus, hermaphroditism, and cystic ovaries. Oral benzo[a]pyrene (BaP) daily for 18 days in the Cyp1a1/1a2(-/-) produced the same degree of marked immunosuppression as seen in the Cyp1a1(-/-) mouse; we believe this reflects the absence of intestinal CYP1A1. Oral BaP-treated Cyp1a1/1a2/1b1(-/-) mice showed the same "rescued" response as that seen in the Cyp1a1/1b1(-/-) mouse; we believe this reflects the absence of CYP1B1 in immune tissues. Urinary metabolite profiles were dramatically different between untreated triple-knockout and wild-type; principal components analysis showed that the shifts in urinary metabolite patterns in oral BaP-treated triple-knockout and wild-type mice were also strikingly different. Liver microarray cDNA differential expression (comparing triple-knockout with wild-type) revealed at least 89 genes up- and 62 genes down-regulated (P-value < or = 0.00086). Gene Ontology "classes of genes" most perturbed in the untreated triple-knockout (compared with wild-type) include lipid, steroid, and cholesterol biosynthesis and metabolism; nucleosome and chromatin assembly; carboxylic and organic acid metabolism; metal-ion binding; and ion homeostasis. In the triple-knockout compared with the wild-type mice, response to zymosan-induced peritonitis was strikingly exaggerated, which may well reflect down-regulation of Socs2 expression. If a single common molecular pathway is responsible for all of these phenotypes, we suggest that functional effects of the loss of all three Cyp1 genes could be explained by perturbations in CYP1-mediated eicosanoid production, catabolism and activities.     

Influence of genetic polymorphisms of CYP1A1 and GSTM1 on the urinary levels of 1-hydroxypyrene

The aim of the present study is to evaluate the influence of the genetic polymorphism of two enzymes involved in the biotransformation of xenobiotics, cytochrome P450 1A1 (CYP1A1) and glutathione-S-transferase M1 (GSTM1), on the urinary levels of 1-hydroxypyrene (1-OH-P) in workers exposed to polycyclic aromatic hydrocarbons (PAHs) and in unexposed workers (controls). The study group consisted of 30 controls recruited among employees of a service company and 171 PAHs-exposed workers from two electric steel plants and an iron foundry (all males, ranging between 18 and 60 years of age). Determination of airborne PAHs and urinary 1-OH-P was performed by high-performance liquid chromatography (HPLC) with fluorimetric detection. Polymerase chain reaction (PCR)-based restriction fragment length polymorphism (RFLP) was used to determine the genetic polymorphisms of CYP1A1 (CYP1A1*2A and CYP1A1*2B) and GSTM1. No influence of the genetic polymorphism of CYP1A1 and GSTM1 on the urinary levels of 1-OH-P was observed in this study.     

Crystal structure of 1:1 complex of barbital with 1-methylimidazole.

The prediction of a strong hydrogen-bonding interaction between barbital and 1-methylimidazole was confirmed. Two crystal complexes were obtained, 1:1 and 2:1, and the X-ray structure was determined for the 1:1 complex, which is monoclinic, space group P21/c, with a = 12.236(3) A, b = 11.332(4) A, c = 12.495(4) A, and beta = 120.67(1) degrees. The structure contains disk-shaped hydrogen-bonded tetramers with two molecules of each kind. There is a short NH...N hydrogen bond (2.82 A) in which barbiturate provides the NH donor.     

Preferential induction of CYP1A1 and CYP1B1 in CCSP-positive cells.

Both benzo[a]pyrene (BaP) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) are potent ligands of aryl hydrocarbon receptors (AhR). Although animal studies indicate that both compounds induce pathological changes in the peripheral lung, the specific cell type involved remains unclear. Clara cells, expressing Clara cell specific protein (CCSP) and abundant in cytochrome P450, are nonciliated bronchiolar epithelial cells in the peripheral lung. Here we explore the hypothesis that CCSP-positive Clara cells are highly responsive to AhR ligands and are the primary cell type involved in BaP- and TCDD-induced toxicities. The responsiveness to AhR ligands was evaluated by measuring the respective mRNA and protein levels of cytochrome P450 1A1 (CYP1A1) and 1B1 (CYP1B1) using real-time RT-PCR and immunocytochemistry assays. Two in vitro models were used: primary cultures of human small airway epithelial (SAE) cells and rat lung slice cultures. In the presence of calcium, human SAE cells differentiated into CCSP-positive cells. BaP- and TCDD-induced mRNA and protein levels of CYP1A1 and CYP1B1 levels were significantly elevated in CCSP-positive cell cultures. Similarly, AhR mRNA and protein levels were increased in CCSP-positive cell cultures, as determined by real-time RT-PCR and Western blot analysis. When rat lung slice cultures were treated with BaP or TCDD for 24 h, CYP1A1 and CYP1B1 proteins were strongly induced in Clara cells. These results indicate that, in the peripheral lung of both rats and humans, CCSP-positive cells (Clara cells) may be more sensitive to AhR ligands than other cell types.     

Inhibitors of aldo-keto reductases AKR1C1-AKR1C4

The AKR1C aldo-keto reductases (AKR1C1-AKR1C4) are enzymes that interconvert steroidal hormones between their active and inactive forms. In this manner, they can regulate the occupancy and trans-activation of the androgen, estrogen and progesterone receptors. The AKR1C isoforms also have important roles in the production and inactivation of neurosteroids and prostaglandins, and in the metabolism of xenobiotics. They thus represent important emerging drug targets for the development of agents for the treatment of hormone-dependent forms of cancer, like breast, prostate and endometrial cancers, and other diseases, like premenstrual syndrome, endometriosis, catamenial epilepsy and depressive disorders. We present here the physiological roles of these enzymes, along with their structural properties and an overview of the recent developments regarding their inhibitors. The most important strategies of inhibitor design are described, which include the screening of banks of natural compounds (like cinnamic acids, flavonoids, jasmonates, and related compounds), the screening of and structural modifications to non-steroidal anti-inflammatory drugs, the substrate-inspired design of steroidal and nonsteroidal inhibitors, and computer-assisted structure-based inhibitor design.     

Neuropharmacological characterization of 1-aminocyclopropane-1-carboxylate and 1-aminocyclobutane-1-carboxylate, ligands of the N-methyl-D-aspartate-associated glycine receptor

Following intravenous administration, 1-aminocyclobutane-1-carboxylate (ACBC, 100 mg/kg), a N-methyl-D-aspartate (NMDA)-associated glycine receptor antagonist, was eliminated with a T1/2 of 5 min in mouse brain and 4 min in rat cerebrospinal fluid (CSF). 1-Aminocyclopropane-1-carboxylate (ACC), a NMDA-associated glycine receptor agonist, was found to have a T1/2 of less than 5 min in mouse brain. ACC and ACBC did not alter basal cerebellar cGMP. Glycine and D-serine increased cGMP, and 1-hydroxy-3-aminopyrrolidone-2 (HA-966), a glycine antagonist, reversed the D-serine-induced increases in cGMP. In contrast, ACBC did not reverse the D-serine-induced increases in cGMP. These data suggest that despite their brain bioavailability and marked potency at the glycine receptor in vitro, ACC and ACBC are rapidly inactivated and thus have limited in vivo utility.