藏红花素诱导人胶质瘤U251细胞内质网应激性凋亡的研究

目的：研究藏红花素对人胶质瘤U251细胞的促凋亡作用和可能的机制。方法：不同浓度藏红花素处理U251细胞后,MTT法检测细胞活力,TUNEL染色观察细胞凋亡情况。结果：①藏红花素显著抑制U251细胞的增殖,并诱导其发生凋亡。②藏红花素增加了U251细胞胞浆内钙离子的含量,并上调了内质网分子伴侣GRP78的表达。③藏红花素处理后的U251细胞内质网相关凋亡分子CHOP,Caspase-4,JNK活性明显增高。结论：藏红花素通过诱导内质网应激性凋亡抑制人胶质瘤U251细胞的增殖。     

蛇床子素对人胶质瘤U251细胞抗增殖作用的研究

目的:研究蛇床子素对人胶质瘤U251细胞的抗增殖作用和可能的机制.方法:不同浓度蛇床子素处理U251细胞后,MTT法检测细胞活力,流式细胞法检测细胞周期和凋亡情况.结果:①蛇床子素显著抑制U251细胞的增殖.②蛇床子素诱导U251细胞发生G2/M期阻滞和凋亡.③蛇床子素处理后的U251细胞PI3K/Akt信号通路活性受到明显抑制.结论:蛇床子素通过抑制PI3K/Akt信号通路抑制人胶质瘤U251细胞的增殖.     

紫草素对人脑胶质瘤U251 细胞增殖和凋亡的影响

目的:观察紫草素对体外培养的人脑胶质瘤U251细胞的增殖和凋亡的影响。方法:应用MTT法和Annexin V-FITC/PI双染流式细胞术分别检测2.5、5、10μM/L的紫草素对U251细胞的体外抑杀作用以及凋亡诱导作用,进一步应用Western blot方法检测紫草素对凋亡相关蛋白Bcl-2及Bax表达水平的影响。结果:紫草素对人U251胶质瘤细胞具有明显的增殖抑制作用,且呈一定的剂量依赖性和时间依赖性。紫草素可明显上调U251细胞Bax的表达,下调Bcl-2的表达,与对照组相比存在显著性差异(P0.05)。结论:紫草素对人胶质瘤U251细胞具有明显的抑制增殖和促进凋亡作用。     

海星皂甙1对人胶质瘤U87细胞抗增殖作用的研究

目的:海星皂甙是一类从海星中分离、萃取出来的甾体苷类,被认为是海星体内毒素的主要成分.研究表明海星皂甙及其化学衍生物具有多种药理学活性,包括抗菌、抗病毒、抗肿瘤、抑制真菌活性等.本实验旨在研究海星皂甙1对人胶质瘤U87细胞的抗增殖作用和可能的机制.方法:不同浓度海星皂甙l处理人胶质瘤U87细胞后,采用MTT法检测细胞活力,TUNEL染色观察细胞凋亡情况,Westernblot检测内质网应激相关凋亡分子的活性.结果:①海星皂甙1显著抑制U87细胞的增殖,呈时间与剂量依赖性.②海星皂甙1诱导U87细胞发生凋亡.③海星皂甙1处理后U87细胞内质网相关凋亡分子活性明显增高.结论:海星皂甙1通过诱导细胞凋亡抑制人胶质瘤U87细胞的增殖,这种抗增殖作用可能是通过激活内质网应激相关凋亡分子实现的.     

丹酚酸B通过抑制线粒体功能增加胶质瘤细胞的放疗敏感性

目的:研究药用植物丹参的根茎提取成分丹酚酸B对人胶质瘤U251细胞的放疗增敏作用,并探讨其可能的分子机制。方法:使用1μM浓度的丹酚酸B处理胶质瘤U251细胞,并用等量PBS建立对照组,使用射线照射建立放射治疗模型。MTT法检测细胞活力;流式细胞术检测细胞凋亡;荧光染色检测活性氧ROS含量及线粒体肿胀程度。结果:丹酚酸B能够显著降低射线照射后U251细胞活力,并增加其凋亡(P0.05)。丹酚酸B能够显著增加射线照射后U251细胞活性氧ROS的产生,并增加线粒体的肿胀程度(P0.05)。结论:丹酚酸B能够通过诱导内源性凋亡增加胶质瘤细胞的放疗敏感性,这种作用可能是通过抑制线粒体功能而实现的。     

Ad-IL-24对人胶质瘤细胞生长抑制效应的体外实验

研究携带人白介素24(IL-24)的腺病毒表达载体(Ad-IL-24)对人U251胶质瘤细胞生长的影响和抗肿瘤分子机制。将不同MOI Ad-IL-24感染U251人胶质瘤细胞后, MTT法检测Ad-IL-24对U251细胞生长的抑制作用, 流式细胞仪和Hochest 染色法检测细胞的凋亡率。RT-PCR检测bcl-2、bax、ICE、C-myc、HIF-1a和p53等基因的转录表达水平, Western blotting检测Cleaved Caspase-3的表达。结果表明100 MOI Ad-IL-24感染U251细胞后能明显抑制细胞生长, 并能明显诱导细胞凋亡, 感染72 h后细胞凋亡率可达42%, 感染4 d后细胞生长抑制率可达50%。RT-PCR检测发现Ad-IL-24能引起与细胞凋亡和血管形成相关基因bax/bcl-2、ICE、C-myc、p53的上调和HIF-1a的下调, 并促进Caspase-3的活化。本研究结果显示Ad-IL-24能明显抑制人胶质瘤细胞U251生长和诱导细胞凋亡, 其抗肿瘤机制可能与通过bax/ bcl-2、ICE、c-myc、p53的上调和HIF-1a的下调, 进而导致Caspase-3的活化而诱导肿瘤细胞发生凋亡有关。     

紫草素对人肝癌HepG2细胞增殖的抑制及诱导凋亡作用

目的:观察紫草素抑制人肝癌HepG2细胞增殖及凋亡诱导的作用。方法:用不同浓度的紫草素处理HepG2细胞,MTT检测紫草素对HepG2细胞生长增殖的抑制作用;比色法测定Caspase-3酶活性;Western blot法检测磷酸化Akt蛋白(pAkt)的表达。结果:紫草素能够抑制人肝癌HepG2细胞的增殖,并呈浓度、时间依赖性,紫草素与HepG2细胞作用24小时后Caspase-3酶活性显著增强,显示紫草素诱导的调亡作用随时间的延长而增加;同时,紫草素处理HepG2细胞后,随着药物浓度的增加,磷酸化Akt蛋白表达下降。结论:紫草素可抑制人肝癌细胞HepG2的增殖,诱导HepG2细胞凋亡,凋亡机制可能与紫草素抑制PI3K/Akt信号途径有关。     

研究报告：CRBGP通过抑制FAK-AKT通路和白介素-6的分泌抑制胶质瘤U251细胞的活性

目的电压门控钠通道(voltage-gated sodium channels,VGSCs)表达于胶质瘤U251细胞,并影响U251细胞的增殖、侵袭和凋亡。富含半胱氨酸的颊腺蛋白(cysteine-rich buccal gland protein,CRBGP)是一种从日本七鳃鳗颊腺中分离出来的VGSCs阻断剂。本文旨在探究CRBGP是否因具有VGSCs阻断功能从而能够抑制U251细胞的活性。方法首先采用MTT法检测了CRBGP对U251细胞增殖的作用,并分别利用莱特-吉姆萨、FITC-phalloidin和Hoechst 33258染色法观察CRBGP处理后U251细胞的形态、细胞骨架和细胞核。细胞外基质蛋白如IV型胶原蛋白、纤连蛋白和层黏连蛋白用于检测CRBGP对U251细胞黏附的影响。此外,本文采用transwell法检测CRBGP处理后U251细胞的迁移和侵袭能力,并通过Western blot方法探讨CRBGP诱导U251细胞凋亡并抑制其运动的内在机理。最后,通过酶联免疫吸附测定法检测CRBGP对U251细胞的抑炎效果。结果 CRBGP通过线粒体依赖途径诱导U251细胞凋亡,...     

藏红花素对C6胶质瘤细胞生长及Survivin和Livin表达的影响

目的:研究藏红花素对大鼠C6胶质瘤细胞生长及凋亡蛋白抑制因子Survivin和Livin表达的影响。方法:体外培养C6胶质瘤细胞,加入不同浓度的藏红花素培养液,并于不同时间点进行观测,采用四甲基偶氮唑蓝(MTT)比色法绘制细胞生长曲线,观察C6细胞的生长活性;通过相差显微镜和Hoechst荧光染色法观察C6细胞的形态学变化;采用Western blot法检测Survivin和Livin蛋白的表达水平。结果:C6胶质瘤细胞经藏红花素作用后细胞生长受到明显抑制,用含2、4和8 mg/ml藏红花素的培养液作用48h后各组C6细胞的OD值分别为0.732±0.013、0.421±0.010和0.289±0.017,细胞生长抑制率分别为26.8±0.01%、58.0±0.02%和71.1±0.02%,其中4 mg/ml和8 mg/ml藏红花素实验组细胞生长抑制率与阴性对照组均有显著性差异(P均0.05);相差显微镜和Hoechst荧光染色法观察显示实验组C6细胞出现典型的凋亡形态学改变;Western blot检测显示实验组C6细胞Survivin和Livin蛋白表达明显下调。结论:藏红花素能明显抑制C6胶质瘤细胞的体外生长,其抑制作用与诱导C6细胞发生凋亡和下调凋亡蛋白抑制因子Survivin和Livin的表达有关。     

HSV-1感染对人星形胶质瘤细胞增殖、凋亡和细胞周期的影响

目的:研究单纯疱疹病毒1型(Herpes simplexvires,HSV-1)感染对人星形胶质瘤细胞U251增殖、凋亡和细胞周期的影响.方法:以感染复数(MOI)为5的HSV-1感染体外培养的U251细胞,在感染后24 h、48 h、72 h和96 h用倒置显微镜观察U251细胞的形态改变:用MTT法、流式细胞术观察HSV-1感染对U251细胞增殖、凋亡和细胞周期的影响.结果:①U251细胞在感染24h后开始出现细胞融合,48 h后开始出现典型的细胞病变效应(Cytopathic effect,CPE),72h后超过80%的细胞出现CPE,.96h后细胞大部分死亡.②MTT法显示HSV-1感染U251细胞24 h、48 h、72 h及96 h的U251细胞OD值均低于对照组(P<0.05).③HSV-1感染U251细胞12h后凋亡率与对照组无显著差异(P0.05),感染24h和36h后凋亡率比相应对照组有显著差别(p<0.05).④HSV感染12h、24h和36h后均可引起U251细胞S期细胞增多和G0/G1期细胞减少,24 h后G2/M期细胞比例开始增加.结论:HSV.1能感染体外培养的U251细胞,抑制其增殖,促进其凋亡并影响其细胞周期.     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.