多组学分析揭示Grb2介导α-硫辛酸抑制肝癌细胞增殖研究

目的:为更深入了解α-硫辛酸如何影响复杂信号通路间的相互作用抑制细胞增殖。方法:我们凭借RNA-Seq与同位素相对标记与绝对定量技术,对α-LA处理24 h HepG2细胞在转录和蛋白表达水平的变化差异进行分析,并借助实时定量PCR免疫印迹技术对组学数据进行了鉴定。结果:转录组学提示共有4,446个基因(2,097个基因表达下调,2,349个基因表达上调)的表达在α-LA处理24 h后呈现显著性改变。GO分析提示,编码肿瘤相关细胞膜蛋白的基因是受α-LA影响最为显著的一类mRNA;蛋白质组学进一步提示Grb2可能是受α-LA调控的膜受体信号通路中关键的靶分子。结论:α-LA抑制HCC细胞增殖是通过下调Grb2介导的相关通路而实现。     

丙戊酸钠抑制A549细胞生长

目的研究丙戊酸钠对肺癌A549细胞增殖和细胞周期的影响。方法MTT检测生长抑制,流式细胞仪检测细胞周期和凋亡,Western blot检测p21WAF1/CIP1蛋白表达。结果丙戊酸钠以剂量依赖性方式抑制A549细胞生长;丙戊酸钠上调G0/G1期比例,下调S期和G2/M期,不影响细胞凋亡;丙戊酸钠上调p21WAF1/CIP1蛋白表达。结论丙戊酸钠上调p21WAF1/CIP1表达,使细胞阻滞于G0/G1期,抑制A549细胞生长。     

维甲酸对A549细胞增殖和凋亡及Skp2、p27^kip1蛋白表达的影响

目的探讨维甲酸对A549细胞增殖和凋亡及相关基因表达的影响。方法MTT法观察ATRA对A549细胞增殖的抑制作用;流式细胞仪、AO/EB荧光双染法检测细胞凋亡;免疫细胞化学检测ATRA处理前后A549细胞Skp2、p27^kip1蛋白表达的情况。结果ATRA处理后①MTT法结果显示ATRA对A549细胞具有增殖抑制作用,在一定范围内呈时间-剂量依赖性。②AO/EB荧光双染色法观察到ATRA 25μmol/L作用A549细胞48h后,即可发现典型的凋亡形态学改变。③流式细胞仪结果出现凋亡峰,与对照组细胞相比,实验组细胞周期延长,主要表现为G0/G1期细胞比例增加,同时S期细胞比例减少。④免疫细胞化学结果显示,ATRA 25μmol/L处理细胞48h后,维甲酸处理组Skp2有明显下调,p27^kip1则明显上调。结论ATRA具有抑制肺腺癌A549细胞增殖,诱导细胞凋亡的作用,其机制可能与下调Skp2,上调p27^kip1蛋白的表达水平有关。     

曲古霉素A抑制肺癌细胞增殖的分子机制

目的:探讨组蛋白去乙酰化酶抑制剂曲古霉素A(trichostatin A,TSA)对人非小细胞肺癌(NSCLC)A549细胞增殖抑制作用及机制.方法:以不同剂量TSA(0.1μM,0.5pM和1μM)处理A549细胞.MTT法检测细胞增殖情况,碘化丙啶(PI)染色结合流式细胞仪检测细胞周期,Westem blot法检测P21蛋白表达,流式细胞仪检测细胞线粒体膜电位和细胞凋亡.结果:TSA剂量依赖性抑制肺癌A549细胞增殖,表现为细胞周期阻滞于G2/M期,同时P21蛋白表达增高;此外,TSA还可以剂量依赖性的促进A549细胞凋亡,伴有线粒体膜电位下降.结论:TSA促进NSCLCA549细胞周期阻滞和凋亡,从而抑制其增殖.     

澳洲茄边碱通过Caspase3蛋白诱导人肺腺癌A549细胞的凋亡作用

运用中药龙葵提取物澳洲茄边碱处理人肺腺癌A549细胞,研究其对A549细胞的抑制及凋亡作用,探讨澳洲茄边碱对肺腺癌的作用机制。通过细胞增殖抑制实验检测不同浓度澳洲茄边碱对A549细胞增殖的影响,采用蛋白印迹法(Western blot)检测凋亡蛋白Caspase3的表达水平,采用流式细胞术测定处理后A549细胞的凋亡水平及细胞周期变化。结果显示,不同浓度澳洲茄边碱均能抑制A549的增殖,呈浓度效应;用不同浓度澳洲茄边碱处理A549细胞24h后,Western blot结果显示,随药物浓度增大,凋亡蛋白Caspase3水解程度增高,对A549凋亡作用明显增强;流式细胞术检测细胞凋亡的结果显示,20μmol·L-1澳洲茄边碱处理A549细胞后,细胞发生明显凋亡,其中早期凋亡细胞比例为25.35%,晚期凋亡细胞比例为11.47%;流式细胞术检测细胞周期的结果显示,20μmol·L-1澳洲茄边碱处理A549细胞后,细胞周期阻滞于G2/M期。本研究结果表明,澳洲茄边碱通过激活细胞凋亡通路中的Caspase3蛋白触发细胞凋亡,同时将A549细胞阻滞在细胞周期的G2/M期,抑制人肺腺癌细胞A549的生长。     

RHCG基因在非小细胞肺癌中的表达及对细胞增殖的影响

为了探讨Rh type C glycoprotein (RHCG)对非小细胞肺癌(non-small cell lung cancer,NSCLC)细胞增殖的影响及可能的作用机制,本研究使用荧光定量PCR法检测12对NSCLC及癌旁组织样本中RHCG mRNA的表达水平及pcDNA3.1-RHCG质粒对A549细胞RHCG m RNA的表达;采用CCK-8法检测细胞增殖能力;运用PI染色法检测细胞周期;使用免疫印迹法检p-PI3K、PI3K、p-AKT以及AKT蛋白表达水平。本研究发现,与癌旁组织比较,NSCLC中RHCG m RNA表达水平明显降低。RHCG过表达能抑制NSCLC细胞系A549细胞增殖能力。此外,RHCG过表达使A549细胞周期G1/S期转化发生阻滞。本研究还发现,RHCG过表达可下调A549细胞p-PI3K/PI3K和p-AKT/AKT水平。本研究表明,RHCG抑制NSCLC细胞增殖的作用与其抑制PI3K/AKT信号通路有关。     

RGD肽对肺癌A549 细胞增殖侵袭能力的影响及其机制研究

目的:研究RGD肽对肺癌A549细胞增殖凋亡及侵袭迁移的影响,并探讨其作用机制。方法:不同浓度RGD肽处理肺癌A549细胞后,MTT检测肺癌细胞的增殖能力,流式细胞仪检测肺癌细胞凋亡及周期分布,Transwell检测其迁移及侵袭能力的变化,Western blot检测RGD肽对肺癌A549细胞MMP2、MMP9的表达水平影响。结果:当RGD肽浓度增加至50 mg/L时,肺癌A549细胞增殖明显受到抑制,且这种抑制作用呈剂量依赖关系;RGD肽组A549细胞G0/G1期细胞比例增高,细胞凋亡率由(6.1±0.1)%增至(15.2±0.5)%;在迁移和侵袭试验中,RGD肽组A549细胞的穿膜细胞数分别由123±10和43±10降至45±5和18±5;RGD肽组A549细胞MMP2、MMP9表达水平显著降低。结论:RGD肽对肺癌A549细胞的增殖有明显抑制作用,并促进其凋亡,可能与RGD肽改变其周期分布有关,RGD肽可明显抑制A549细胞的迁移及侵袭,可能与其下调MMP2、MMP9的表达相关。     

P15INK4B高表达对人黑色素瘤细胞G1/S进程的阻滞及与MAPK信号相关性之初探

利用TdR-N_2O同步法分别获得P15高表达的MLIK6和表达空载体的MLC2的M期细胞和G_1期细胞,~3H-TdR掺入结果显示,与对照组细胞MLC2相比,实验组细胞MLIK6从G_1期进入S期时间延长2h,并且掺入强度明显减弱,DNA合成被抑制。进一步观察了P15~(INK4B)对G_1/S相关调控蛋白的影响,在M期细胞释放8h(晚G_1期细胞)后,与对照组MLC2细胞相比,实验组MLIK6细胞中CyclinD1,CyclinE,Cdk4,C-Myc蛋白水平均降低。相反,P27~(KIP1)的表达却上升。同时探讨了MAPK信号在P15~(INK4B)阻抑A375细胞G_1/S转换中的作用与相关性,结果显示晚G_1期的MLIK6细胞中ERK1,ERK2水平变化不大,而具有活性的P-ERK1和P-ERK2均表现出下降。上述实验表明,P15~(INK4B)可能通过作用于G_1期相关的周期调节蛋白和抑制ERK1和ERK2活性,阻滞G_1/S转换与抑制DNA合成。     

茅苍术提取物在肺癌A549细胞中的抗增殖作用机制

目的:研究茅苍术提取物对肺癌A549细胞的肿瘤增殖抑制效果及机制。方法:MTT比色法检测茅苍术提取物对A549细胞增殖的抑制效果;流式细胞术分析茅苍术提取物对肺癌A549细胞周期的影响;Western Blot检测茅苍术刺激前后细胞周期蛋白D1(cyclin D1)蛋白表达量变化。结果:茅苍术提取物能有效抑制肺癌A549细胞增殖,且抑制效果与茅苍术提取物浓度呈现依赖性,茅苍术提取物刺激48h后,抑制效果最佳,IC50约为77.12μg/ml;细胞周期分析显示:茅苍术提取物可将细胞周期阻滞在G0/G1期,50μg/ml茅苍术提取物刺激48h后,G1期上升至53.41%;cyclin D1蛋白含量因茅苍术作用而下调。结论:茅苍术提取物能通过有效抑制cyclin D1的表达,进而将细胞周期阻滞于G1期,最终实现其抗增殖作用机制。     

缺氧条件下人脐带源性间充质干细胞增强缺氧诱导因子-1α表达促进肺腺癌细胞增殖

目的探讨缺氧条件下缺氧诱导因子-1α(hypoxia-inducible factor-1α, HIF-1α)在人脐带源性间充质干细胞(human umbilical cord-derived mesenchymal stem cells, hucMSCs)促进肺腺癌A549细胞增殖过程中的可能机制。方法分离培养和鉴定hucMSCs,分别与肺腺癌A549细胞、干扰了HIF-1α基因的A549细胞在常氧或缺氧条件下进行共培养,荧光定量PCR和Western blot法分别检测HIF-1α和生存素(survivin)表达水平,MTT法检测细胞增殖力,划痕实验分析细胞迁移力。结果 MTT和划痕实验检测显示,常氧条件下,hucMSCs共培养的A549 细胞增殖能力、迁移能力较无hucMSCs共培养的细胞明显减弱;缺氧条件下,A549 细胞增殖力和迁移力较常氧培养的A549 细胞明显增强,hucMSCs共培养使二者进一步增强,沉默HIF-1α则使二者减弱,hucMSCs共培养不改变沉默HIF-1α对细胞增殖力和迁移力的影响。荧光定量PCR和Western blot检测显示,缺氧培养时,A549 细胞内HIF-1α和survivin表达明显上调,hucMSCs共培养明显增强缺氧对HIF-1α和survivin表达的上调作用;沉默HIF-1α抑制缺氧对A549细胞HIF-1α和survivin表达的上调,hucMSCs共培养不改变沉默HIF-1α对HIF-1α和survivin表达上调的抑制。结论缺氧条件下,hucMSCs共培养导致肺腺癌A549细胞HIF-1α和survivin表达上调,从而使A549细胞的增殖和迁移能力增强。     

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.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细