二甲双胍联合塞来昔布对胰腺癌细胞增殖及Caspase-3活性的影响

目的:探讨二甲双胍和塞来昔布单独或联合应用对胰腺癌细胞增殖和Caspase-3活性的影响。方法:体外培养人胰腺癌BxPC-3和As PC-1细胞,用四甲基偶氮唑盐(MTT)法检测不同浓度二甲双胍和塞来细胞对胰腺癌细胞存活率的影响。联合实验分4组:对照组、二甲双胍组(MET,15 mmol/L)、塞来昔布组(CEL,100μmmol/L),二甲双胍和塞来昔布联合组(MET 15 mmol/L+CEL100μmmol/L),孵育48 h,用MTT检测细胞存活率,用Caspase-3比色测定试剂盒测定Caspase-3活性。结果:二甲双胍和塞来昔布单药均可以时间和剂量依赖性方式降低胰腺癌Bx PC-3和As PC-1细胞的生存率。两种细胞系的各加药组细胞存活率与对照组比较差异均存在统计学意义(P0.01),联合实验组的细胞存活率明显低于单独用药组(P0.01)。二甲双胍和塞来昔布单药处理的胰腺癌Bx PC-3和As PC-1细胞Caspase-3活性均显著高于对照组(P0.01),二甲双胍和塞来昔布联合实验组Caspase-3活性均明显高于单药处理组和对照组(P0.01),但二甲双胍组和塞来昔布组之间的Caspase-3活性比较差异无统计学意义(P0.05)。结论:二甲双胍和塞来昔布联合作用可协同抑制胰腺癌细胞的增殖,并通过激活Caspase-3活性促进胰腺癌细胞的凋亡,其联合应用可能成为胰腺癌药物治疗的有效策略。     

Celecoxib 联合X 线对胆管癌细胞株QBC939 凋亡的影响

目的:研究塞来昔布联合X线在体外环境下对人胆管癌细胞株QBC939凋亡的影响并对其机制进行初步探讨。方法:CCK-8检测出不同浓度的塞来昔布及不同剂量的X线对QBC939细胞株的增值抑制率,确定塞来昔布组的IC50及X线组的IC50。将QBC939细胞株分为5组:对照组(control)、X线组(R)、塞来昔布组(C)、塞来昔布再加X线组(C+R),X线再加塞来昔布组(R+C)。用流式细胞仪检测各组的凋亡率,western blot检测凋亡相关基因survivin蛋白的表达。结果:联合使用塞来昔布和放疗组的凋亡率有明显的增加,从8.268%,11.233%到15.733%,22.133%(P<0.05)。western结果显示联合组survivin蛋白的表达也明显低于对照组(P<0.05)。先用塞来昔布再加放疗的效果要优于先用放疗后用塞来昔布的效果。结论:塞来昔布联合X线对QBC939细胞株有凋亡增敏作用,作用可能机制之一是通过降低或下调凋亡相关基因survivin蛋白的表达。     

存活素反义寡核苷酸在人甲状腺髓样癌裸鼠模型中的抑瘤作用

目的探讨存活素(survivin)反义寡核苷酸(antisense oligodeoxyribonucleotide,ASODN)在人甲状腺髓样癌裸鼠模型中的抑瘤作用。方法构建12只人甲状腺髓样癌裸鼠模型,随机分配到正常组,SODN(sense oligodeoxyribonucleotide,正义寡核苷酸)组和ASODN组,每组4只。各组每日一次瘤内注射相应处理液,连续7d。治疗结束后1周,杀死全部瘤鼠,切取瘤体,测算瘤重和抑瘤率以评价肿瘤生长情况,瘤组织石腊切片分别行HE、免疫组化(IHC)和DNA末端原位标记法(TUNEL法)染色以评价组织病理构造、survivin与VEGF蛋白表达和细胞凋亡的变化。结果HE染色显示ASODN组具有明显减低的血管新生特点。此外,相对于正常组和SODN组,ASODN组具有显著的survivin和VEGF低表达、高凋亡、低瘤重和高抑瘤率特点(各P<0.01),而正常组与SODN组间未见上述各特点的统计学差异。结论本研究证实针对人甲状腺髓样癌survivin基因沉默治疗能够达到明显抑瘤效果,此效果至少部分通过促进肿瘤调亡和抑制肿瘤血管新生而实现。这提示survivin基因在人甲状腺髓样癌中具有重要意义和其可成为人甲状腺髓样癌基因靶向沉默治疗的重要候选基因之一。     

塞来昔布联合氟尿嘧啶对胰腺癌细胞株SW1990生长抑制作用及其机制研究

目的:研究选择性环氧化酶-2(COX-2)抑制剂塞来昔布联合氟尿嘧啶对胰腺癌细胞株SW1990生长的抑制作用,并对其机制进行初步探讨.方法:实验分为对照组、氟尿嘧啶组、塞来昔布组及两药联合组,将不同浓度的药物分剐作用于胰腺癌细胞株SW1990,MTT法检测各组细胞的生长抑制率,并探索产生最佳细胞生长抑制作用的药物浓度.流式细胞仪检测不同药物作用对肿瘤细胞周期的影响.RT-PCR检测各组细胞Survivin的表达情况.结果:MTT法显示氟尿嘧啶、塞来昔布均能抑制SW1990的生长,且细胞的存活率都随药物浓度的增加而降低.两药联合组对细胞生长的抑制作用更明显.流式细胞仪检测结果显示塞来昔布组、氟尿嘧啶组及两药联合组细胞较对照组G0/G1期细胞比例明显增加,S期和G2/M期细胞比例明显减少.RT-PCR结果显示氟尿嘧啶组、塞来昔布组、联合组都可下调Survivin的表达,以联合组最为明显.结论:塞来昔布联合氟尿嘧啶对胰腺癌SW1990细胞的生长具有抑制作用,其机制可能与下调Survivin的表达从而诱导细胞的凋亡和细胞周期的停滞有关.     

塞来昔布诱导前列腺癌细胞凋亡及其机制研究

目的:研究塞来昔布对前列腺癌DU-145细胞凋亡及侵袭力的影响,并探讨其可能作用机制.方法:应用Hoechst 33342/PI染色检测细胞凋亡形态;Annexin V-FITC/PI双染色流式细胞术检测不同浓度塞来昔布诱导细胞凋亡能力;RT-PCR法检测塞来昔布作用后Bcl-2、E-cadherin、ICE及COX-2 mRNA表达水平的变化.结果:Hoechst 33342/PI双染色可观察到药物作用后.细胞呈现明显凋亡现象.流式细胞术证实塞来昔布能有效诱导细胞凋亡,0、25、50、100、200μmol/L塞来昔布诱导细胞凋亡率分别为(1.10±0.15)%,(3.87±0.79)%,(10.59±1.58)%,(22.50±3.30)%,(33.85±2.71)%,细胞凋亡率呈现浓度依赖性递增.RT-PCR显示Bcl-2mRNA表达水平下调,E-cadherin mRNA表达水平上调,ICE mRNA表达水平无明显变化,COX-2 mRNA未检测到.结论:塞采昔布能有效诱导前列腺癌DU-145细胞凋亡并使其侵袭力降低.     

二甲双胍增强胰腺癌放疗敏感性的体外及体内实验研究

目的:探讨二甲双胍对胰腺癌细胞和胰腺癌裸鼠移植瘤放疗敏感性的影响。方法:体外培养人胰腺癌Bx PC-3和As PC-1细胞,分为二甲双胍处理组和未处理组,处理组给予10 mmol/L二甲双胍作用48小时后分别给予0、1、2、4、6、8Gy射线对两种细胞进行照射,运用克隆形成实验,Giemsa染色后计算克隆形成率及SF2,并拟合细胞存活曲线。应用裸鼠皮下注射胰腺癌细胞,建立两种细胞的裸鼠移植瘤模型,裸鼠肿瘤体积达到100 mm~3时,作为0天,并开始分组,每种移植瘤使用24只裸鼠随机分为4组:生理盐水对照组、单纯二甲双胍治疗组、单纯照射组、二甲双胍+照射组,二甲双胍处理组每天给予250 mg/kg(50μL/每只)腹腔注射,对照组仅给予等量生理盐水注射(50μL/每只)。每4天用游标卡尺测量移植瘤的长径和宽径,并绘制生长曲线。当对照组体积达到200 mm~3时,照射组和联合组,给予一次性照射6Gy射线,当对照组体积达到1000 mm~3时,将裸鼠进行麻醉,剥出皮下移植瘤,进行称量和保存,并计算抑瘤率。结果:两细胞系经过二甲双胍处理后,经2、4、6、8Gy照射后存活分数明显低于未处理组(P0.01),随着照射剂量的增大,克隆形成数量明显减少,两个细胞系经二甲双胍处理后进行照射,其SF2、D0,N值均较未处理组明显减少(P0.01),表明经二甲双胍处理后,Bx PC-3细胞和As PC-1细胞的放射敏感性增强,增敏比分别为1.2368和1.1179。二甲双胍和放射联合处理组的体积、瘤重均明显小于对照组和单独处理组,Bx PC-3和As PC-1移植瘤的抑瘤率分别为62.14%、61.53%,均明显高于各自单独处理组(P0.01或P0.05)。结论:二甲双胍能够增强胰腺癌的放疗敏感性,在临床上具有潜在的应用价值。     

选择性环氧化酶-2抑制剂对乳腺癌细胞的化疗增敏作用

目的:观察选择性环氧化酶-2(COX-2)的抑制剂塞来昔布对表柔比星抗乳腺癌MCF-7细胞增殖和诱导凋亡作用以及探讨其机制.方法:应用四甲基偶氮唑蓝(MTT)比色法分析塞来昔布联用表柔比星对MCF-7细胞的生长抑制作用,流式细胞术检测细胞的凋亡,western blotting检测凋亡相关蛋白Bcl-2、Bax、caspase-3的表达.结果:10μmol/l的cxlecoxib和10μg/l表柔比星联用细胞抑制率和早期凋亡率均显著增高,并引起caspase-3上调及裂解激活,bcl-2下调,bax则变化不大.结论:塞来昔布对表柔比星抗乳腺癌MCF-7细胞有协同作用,其诱导凋亡与caspase-3激活和Bcl-2表达下调有关.     

选择性环氧合酶-2抑制剂塞来昔布抑制胃癌多药耐药基因表达的实验研究

目的:探讨选择性环氧合酶(COX-2)抑制剂塞来昔布对胃癌细胞株BGC823多药耐药(mdr)1表达的影响.方法:胃癌细胞株BGC823经浓度分别为0、10、100μ mol/L的塞来昔布处理后,酶联免疫吸附试验检测塞来昔布对胃癌细胞前列腺素E2(PGE2)分泌的影响,24、48 h后用RT-PCR检测多药耐药(mdr)1 mRNA表达,48 h后用免疫细胞化学染色法检测P-gp表达.结果:塞来昔布可显著抑制胃癌细胞株BGC823 PGE2分泌.并呈浓度依赖性(P<0.05).不同浓度塞来昔布作用于细胞后,胃癌细胞株BGC823的mdrl/P-gp表达受不同程度抑制,100μ mol/L的塞来昔布对mdrl mRNA表达抑制作用强于10μ mol/L(P<0.01).不同浓度药物与测量时间为交互作用,作用48h与24h相比,塞来昔布对mdrl mRNA表达的抑制作用更强(P<0.01).结论:塞来昔布可抑制BGC823的mdrl/P-gp表达,且呈剂量效应关系.塞来昔布可能通过抑制COX-2活性,抑制COX-2下游产物PGE2表达,从而抑制P-gp表达.选择性COX-2抑制剂可能有助于减轻肿瘤细胞对化疗药物的耐药性.     

小窝蛋白-1对洛伐他汀联合塞来昔布治疗宫颈癌的分子影响

探讨洛伐他汀联合塞来昔布作用于宫颈癌细胞SiHa的关键分子及对下游信号分子的影响。分别用不同浓度的洛伐他汀和塞来昔布孵育宫颈癌细胞Si Ha,根据CCK-8试剂盒检测24 h的细胞增殖结果,计算两药的IC_(50)。用IC_(50)浓度的洛伐他汀和塞来昔布作用于SiHa,qPCR检测小窝蛋白-1的mRNA水平变化以及Akt、ERK1/2和STAT3的磷酸化水平。SiHa细胞经洛伐他汀和塞来昔布处理24 h后,IC_(50)值分别为25μmol/L和50μmol/L;洛伐他汀或塞来昔布单独处理Si Ha细胞24 h,均可从蛋白水平抑制小窝蛋白-1的表达;并且洛伐他汀可协同塞来昔布降低小窝蛋白-1引起的Akt、ERK1/2和STAT3信号分子磷酸化。洛伐他汀和塞来昔布联合应用下调宫颈癌细胞小窝蛋白-1的表达,并且可以显著性抑制下游信号分子的激活。     

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.