Rice leaf inclination2, a VIN3-1ike protein, regulates leaf angle through modulating cell division of the collar

As an important agronomic trait, inclination of leaves is crucial Ior crop architecture and grain yields. 10 understand the molecular mechanism controlling rice leaf angles, one rice leaf inclination2 （1c2, three alleles） mutant was identified and functionally characterized. Compared to wild-type plants, lc2 mutants have enlarged leaf angles due to increased cell division in the adaxial epidermis of lamina joint. The LC2 gene was isolated through positional cloning, and encodes a vernalization insensitive 3-like protein. Complementary expression of LC2 reversed the enlarged leaf angles of lc2 plants, confirming its role in controlling leaf inclination. LC2 is mainly expressed in the lamina joint during leaf development, and particularly, is induced by the phytohormones abscisic acid, gibberellic acid, auxin, and brassinosteroids. LC2 is localized in the nucleus and defects of LC2 result in altered expression of cell division and hormone-responsive genes, indicating an important role of LC2 in regulating leaf inclination and mediating hormone effects.

Spatial perturbation with synthetic protein scaffold reveals robustness of asymmetric cell division

Asymmetric cell division is an important mechanism for creating diversity in a cellular population. Stem cells commonly perform asymmetric division to generate both a daughter stem cell for self-renewal and a more differentiated daughter cell to populate the tissue. During asymmetric cell division, protein cell fate determinants asymmetrically localize to the opposite poles of a dividing cell to cause distinct cell fate. However, it remains unclear whether cell fate determination is robust to fluctuations and noise during this spatial allocation process. To answer this question, we engineered Caulobacter, a bacterial model for asymmetric division, to express synthetic scaffolds with modular protein interaction domains. These scaffolds perturbed the spatial distribution of the PleC-DivJ- DivK phospho-signaling network without changing their endogenous expression levels. Surprisingly, enforcing symmetrical distribution of these cell fate de terminants did not result in symmetric daughter fate or any morphological defects. Further computational analysis suggested that PleC and DivJ form a robust phospho-switch that can tolerate high amount of spatial variation. This insight may shed light on the presence of similar phospho-switches in stem cell asymmetric division regulation. Overall, our study demonstrates that synthetic protein scaffolds can provide a useful tool to probe biological systems for better understanding of their operating principles.

The promoting molecular mechanism of alphafetoprotein on the growth of human hepatoma Bel7402 cell line

AIM: The goal of this study was to characterize the AFP receptor, its possible signal transduction pathway and its proliferative functions in human hepatoma cell line Bel 7402. METHODS: Cell proliferation enhanced by AFP was detected by MTT assay, 3H-thymidine incorporation and S-stage percentage of cell cycle analysis. With radioactive labeled 125I-AFP for receptor binding assay; cAMP accumulation, protein kinase A activity were detected by radioactive immunosorbent assay and the change of intracellular free calcium (Ca2+i) was monitored by scanning fluorescence intensity under TCS-NT confocal microscope. The expression of oncogenes N- ras, p 53, and p21( ras ) in the cultured cells in vitro were detected by Northern blotting and Western blotting respectively. RESULTS: It was demonstrated that AFP enhanced the proliferation of human hepatoma Bel 7402 cell in a dose dependent fashion as shown in MTT assay, (3)H-thymidine incorporation and S-phase percentage up to 2-fold. Two subtypes of AFP receptors were identified in the cells with Kds of 1.3 x 10(-9)mol.L(-1) and 9.9 x10(-8)mol. (-1)L respectively. Pretreatment of cells with AFP resulted in a significant increase (625%) in cAMP accumulation. The activity of protein kinase A activity were increased up to 37.5, 122.6, 73.7 and 61.2% at treatment time point 2, 6, 12 and 24 hours. The level of intracellular calcium were elevated after the treatment of alpha-fetoprotein and achieved to 204% at 4 min. The results also showed that AFP(20mg.L(-1)) could upregulate the expression of N- ras oncogenes and p 53 and p21( ras ) in Bel 7402 cells. In the later case,the alteration were 81.1%(12h) and 97.3%(12h) respectively compared with control. CONCLUSION: These results demonstrate that AFP is a potential growth factor to promote the proliferation of human hepatoma Bel 7402 cells. Its growth-regulatory effects are mediated by its specific plasma membrane receptors coupled with its transmembrane signaling transduction through the pathway of cAMP-PKA and intracellular calcium to regulate the expression of oncogenes.

Effect of transforming growth factor beta and bone morphogenetic proteins on rat hepatic stellate cell proliferation and transdifferentiation

AIM: To explore different roles of TGF-β (transforming growth factor beta) and bone morphogenetic proteins (BMPs)in hepatic stellate cell proliferation and trans-differentiation.METHODS: Hepatic stellate cells were isolated from male Sprague-Dawley rats. Sub-cultured hepatic stellate cells were employed for cell proliferation assay with WST-1 reagent and Western blot analysis with antibody against smooth muscle alpha actin (SMA).RESULTS: The results indicated that TGF-β1 significantly inhibited cell proliferation at concentration as low as 0.1 ng/ml, but both BMP-2 and BMP-4 did not affect cell proliferation at concentration as high as 10 ng/ml. The effect on hepatic stellate cell trans-differentiation was similar between TGFβ1 and BMPs. However, BMPs was more potent at transdifferentiation of hepatic stellate cells than TGF-β1. In addition, we observed that TGF-β1 transient reduced the abundance of SMA in hepatic stellate cells.CONCLUSION: TGF-β may be more important in regulation of hepatic stellate cell proliferation while BMPs may be the major cytokines regulating hepatic stellate cell transdifferentiation.

The intracellular mechanism of alpha-fetoprotein promoting the proliferation of NIH 3T3 cells

AIM: The existence and properties of alpha-fetoprotein (AFP) receptor on the surface of NIH 3T3 cells and the effects of AFP on cellular signal transduction pathway were investigated. METHODS: The effect of AFP on the proliferation of NIH 3T3 cells was measured by incorporation of 3H-TdR. Receptor-binding assay of 125I-AFP was performed to detect the properties of AFP receptor in NIH 3T3 cells. The influences of AFP on the [cAMP]i and the activities of protein kinase A (PKA) were determined. Western blot was used to detect the change of K-ras P21 protein expression. RESULTS: The proliferation of NIH 3T3 cells treated with 0-80 mg/L of AFP was significantly enhanced. The Scatchard analysis indicated that there were two classes of binding sites with KD of 2.722 x 10(-9)M (Bmax=12810 sites per cell) and 8.931 x 10(-8)M (Bmax=119700 sites per cell) respectively. In the presence of AFP (20 mg/L), the content of cAMP and activities of PKA were significantly elevated . The level of K-ras P21 protein was upregulated by AFP at the concentration of 20 mg/L. The monoclonal antibody against AFP could reverse the effects of AFP on the cAMP content, PKA activity and the expression of K-ras p21 gene. CONCLUSION: The effect of AFP on the cell proliferation was achieved by binding its receptor to trigger the signal transduction pathway of cAMP-PKA and alter the expression of K- ras p21 gene.

CDC20在肺腺癌组织中的表达及对肺腺癌细胞增殖和侵袭的影响研究

背景与目的:肺腺癌具有早期发现难、肿瘤进展快及晚期手术切除率低等特点。尽管单药免疫治疗和免疫治疗联合化疗的相关研究在改善预后、克服耐药方面已初显成效,但是大部分肺腺癌患者从中获益仍有限。因此,迫切需要寻找具有相对较高灵敏度和特异度的新型生物标志物,以改善肺腺癌患者的预后。细胞分裂周期蛋白20(cell division cycle protein 20,CDC20)参与多种肿瘤的发生、发展,但在肺腺癌中的生物学作用及机制尚未明确。本研究旨在探究CDC20在肺腺癌中的表达情况及其对肺腺癌患者预后的预测价值,并分析CDC20对肺腺癌细胞增殖和侵袭能力的影响。方法:采用免疫组织化学(immunohistochemistry,IHC)检测CDC20在肺腺癌中的表达情况并结合生物信息学和临床病理学参数分析其与预后不良的相关性。采用Kaplan-Meier生存曲线描述CDC20对肺腺癌患者术后生存率的影响,采用COX多因素回归分析影响肺腺癌患者术后生存率的独立预后因素。通过受试者工作特征曲线分析CDC20表达在肺腺癌患者中的诊断价值。采用实时荧光定量聚合酶链反应(real-time fluorescence quantitative polymerase chain reaction,RTFQ-PCR)和蛋白质印迹法(Western blot)检测人正常肺上皮细胞系BEAS-2B、人肺腺癌细胞系A549和H1299中CDC20的表达水平。细胞实验中,通过敲低肺腺癌细胞中的CDC20,分为si-NC(对照组)、si-CDC20#1(敲低组1)和si-CDC20#2(敲低组2)3个组。采用细胞计数试剂盒-8(cell counting kit-8,CCK-8)、克隆形成、transwell和划痕实验检测细胞增殖、迁移和侵袭能力。通过基因本体论(Gene Ontology,GO)功能和京都基因与基因组百科全书(Kyoto Encyclopedia of Genes and Genomes,KEGG)通路富集分析CDC20在肺腺癌中的生物学作用。通过基因集富集分析(gene set enrichment analysis,GSEA)CDC20在肺腺癌中可能的调控通路。本研究经河北省胸科医院伦理委员会批准(编号:2022051)。结果:生物信息学及IHC结果均显示,CDC20在肺腺癌组织中显著高表达(P<0.05)。生物信息学与临床参数分析结果均显示,CDC20高表达与患者预后不良相关。Kaplan-Meier生存分析和COX回归分析均显示,CDC20表达情况与患者术后生存率呈显著负相关(P<0.05)。敲低CDC20能抑制肺腺癌细胞增殖、迁移和侵袭(P<0.05)。GO功能、KEGG通路和GSEA结果均显示,CDC20与细胞周期相关。结论:CDC20在肺腺癌中高表达,CDC20高表达是肺腺癌患者不良预后的独立危险因素。CDC20能促进肺腺癌细胞增殖、迁移和侵袭。

CDCA5基因在子宫颈癌组织细胞中表达变化及对肿瘤细胞增殖的影响

目的 观察细胞分裂周期相关蛋白5(CDCA5)基因在子宫颈癌组织细胞中的表达变化,观察CDCA5基因过表达对子宫颈癌细胞增殖能力的影响,并探讨可能的分子机制。方法 收集子宫颈癌组织和癌旁正常组织各60例,培养人宫颈上皮永生化细胞系H8和人子宫颈癌细胞系SiHa、C-33A、MS751、HeLa,采用实时荧光定量PCR法检测组织和细胞中的CDCA5 mRNA。将CDCA5 mRNA相对表达量最低的子宫颈癌细胞随机分为对照组、过表达组,分别转染pCDH空载体质粒、CDCA5过表达质粒,采用CCK-8实验、克隆形成实验检测细胞增殖能力,Western blotting法检测细胞中的p-ERK、p-AKT蛋白。结果 子宫颈癌组织中CDCA5 mRNA相对表达量高于癌旁组织(P<0.05);子宫颈癌细胞系SiHa、C-33A、MS751、HeLa中CDCA5 mRNA表达高于H8细胞,其中HeLa细胞中相对表达量最低(P均<0.05)。过表达组24、48、72 h细胞增殖能力高于对照组,过表达组细胞平板克隆形成数量及p-ERK、p-AKT蛋白表达高于对照组(P均<0.05)。结论 CDCDA5基因在子宫颈癌组织、细胞中高表达,CDCDA5基因过表达可增强人子宫颈癌细胞的增殖能力,该作用可能与调控ERK/AKT信号通路有关。

SGK3在小鼠卵母细胞第一次减数分裂恢复中的作用及其机制

目的:探讨血清和糖皮质激素诱导的蛋白激酶3(SGK3)在小鼠卵母细胞第一次减数分裂恢复中的作用,初步阐明SGK3在哺乳动物卵母细胞早期发育中的调控机制。方法:利用超排卵技术获取生发泡(GV)期小鼠卵母细胞,利用显微注射技术将表达质粒体外转录获得的SGK3 mRNA注射至GV期卵母细胞,分为对照组、Tris-EDTA缓冲液(TE)组和SGK3 mRNA组,采用Western blotting法检测各组小鼠卵母细胞中SGK3蛋白表达水平,显微注射SGK3 mRNA后1、2、3和4 h观察并计算各组卵母细胞生发泡破裂(GVBD)率,采用SGK3抗体稀释抑制实验观察各组卵母细胞形态表现,采用Western blotting法检测体外培养不同时间点卵母细胞中磷酸化SGK3(pSer48)(SGK3-pSer48)和磷酸化细胞分裂周期蛋白2(CDC2)(pTyr15)(CDC2-pTyr15)蛋白表达水平。结果:与对照组和TE组比较,SGK3 mRNA组小鼠卵母细胞中SGK3蛋白表达水平升高(P<0.01),显微注射后1和2 h时GVBD率升高(P<0.01)。SGK3抗体稀释抑制实验,随着SGK3抗体浓度增加,各组小鼠卵母细胞GVBD率呈浓度依赖性降低。过表达SGK3后,与对照组比较,SGK3 mRNA组小鼠卵母细胞中检测不到CDC2-pTyr15蛋白表达的时间至少提前1 h。不同稀释浓度SGK3抗体作用后,与对照组比较,随着SGK3抗体浓度升高和时间的延长,小鼠卵母细胞中CDC2-pTyr15蛋白表达水平逐渐降低(P<0.01),SGK3-pSer486蛋白表达水平逐渐升高(P<0.01)。结论:过表达SGK3可以增加小鼠卵母细胞GVBD率,加快CDC2-pTyr15的脱磷酸化,而CDC2-pTyr15的脱磷酸化晚于SGK3-Ser486的磷酸化。SGK3可能作为CDC2上游调节因子参与调控小鼠卵母细胞第一次减数分裂的恢复。

藏红花素通过跨膜受体蛋白/发状分裂相关增强子1信号通路对缺氧诱导的视网膜神经节细胞凋亡的影响

目的探讨藏红花素对缺氧诱导的视网膜神经节细胞凋亡的作用及其可能机制。方法于2021年1月至2022年1月采用不同浓度藏红花素处理视网膜神经节细胞RGC-5,四甲基噻唑蓝(MTT)法检测细胞存活情况并筛选合适浓度。培养RGC-5细胞并用氯化钴(CoCl_(2))处理建立缺氧模型,分为缺氧组、藏红花素组、阳性对照(抗坏血酸)组和藏红花素+跨膜受体蛋白信号通路抑制剂(DAPT)组,另设对照组。Cell counting kit-8法检测细胞存活情况;采用流式细胞术检测细胞凋亡率;钙荧光探针(Flou-4)实验检测各组细胞钙离子水平;实时定量PCR法检测跨膜受体蛋白(Notch1)、发状分裂相关增强子1(Hes-1)mRNA表达情况;蛋白质印迹法检测凋亡蛋白B细胞淋巴瘤因子2(Bcl-2)、Bcl-2相关蛋白(Bax)、钙依赖性蛋白酶家族1(Cal⁃pain1)蛋白表达情况。结果藏红花素组细胞活力0.83±0.08高于缺氧组0.45±0.04,细胞凋亡率(17.92±1.21)%低于缺氧组(51.82±5.36)%,钙离子水平0.27±0.04低于缺氧组0.76±0.05,差异有统计学意义(P<0.05);藏红花素+DAPT组细胞活力0.50±0.06低于藏红花素组0.83±0.08,细胞凋亡率(36.50±3.50)%高于藏红花素组(17.92±1.21)%,钙离子水平0.65±0.05高于藏红花素组0.27±0.04,差异有统计学意义(P<0.05)。与缺氧组比较,藏红花素组Bcl-2蛋白表达水平升高,Notch1、Hes-1mRNA表达、Bax和Calpain1蛋白表达水平降低(P<0.05)。与藏红花素组比较,藏红花素+DAPT组Bcl-2蛋白表达水平降低,Notch1、Hes-1mRNA表达、Bax和Calpain1蛋白表达水平升高(P<0.05)。结论藏红花素对体外培养的缺氧RGC-5细胞凋亡有一定的抑制作用,可能是通过抑制钙离子内流,阻滞Notch1/Hes-1通路,提高细胞内抑凋亡蛋白Bcl-2表达水平发挥作用。

皮肤黑素瘤中细胞分裂周期相关蛋白8的表达水平及功能学分析

目的基于生物信息学方法分析CDCA8在皮肤黑素瘤组织中的表达水平及其相关生物学功能。方法TCGA数据库中下载皮肤黑素瘤数据集,分析CDCA8在皮肤黑素瘤组织中的表达,K-M曲线分析皮肤黑素瘤组织中CDCA8表达水平与总体生存率的关系,UALCAN数据库筛选皮肤黑素瘤中与CDCA8的共表达基因,并对共表达基因进行GO和KEGG富集分析。TIMER数据库分析皮肤黑素瘤组织中CDCA8与免疫细胞浸润的相关性。HPA数据库验证CDCA8在皮肤黑素瘤组织及正常组织中的表达差异。结果与正常组织相比,CDCA8在皮肤黑素瘤组织中明显高表达(P<0.5);与皮肤黑素瘤TP-53野生型相比,CDCA8表达水平在TP-53突变型中明显升高(P<0.05)。皮肤黑素瘤中CDCA8高表达组总体生存率显著低于CDCA8低表达组(HR=1.500,P=0.005)。皮肤黑素瘤组织中CDCA8共表达基因主要富集于细胞核、细胞质、细胞分裂、细胞周期、DNA修复、蛋白结合、RNA结合、细胞周期、DNA复制及细胞核质转运等过程。皮肤黑素瘤中CDCA8与B细胞(r=0.166,P<0.001)、CD8^(+)T细胞(r=0.176,P<0.001)、中性粒细胞(r=0.193,P<0.001)及树突状细胞(r=0.230,P<0.001)浸润程度存在显著正相关性。免疫组化显示CDCA8在皮肤黑素瘤组织中均呈现高强度表达,而在正常组织中无表达或低表达。结论CDCA8在皮肤黑素瘤组织中呈现高表达状态,与患者不良预后显著相关,CDCA8可能通过调控细胞周期及免疫细胞浸润参与皮肤黑素瘤的发病机制。

基于数据挖掘技术探讨细胞分裂周期相关蛋白在肝细胞癌中的表达及对预后的影响

目的 基于数据挖掘技术研究细胞分裂周期相关蛋白(CDCA)在肝细胞癌(HCC)中的表达特征及其与临床病理分期和预后的关系。方法 通过TCGA数据库获得266例HCC组织及50例正常肝组织样本数据,分析CDCA在HCC与正常肝组织中表达的差异,再以CDCA基因表达中位数为界将HCC组织分为高、低表达组,每组133例。Kaplan-Meier法比较高、低表达组患者总生存期(OS)差异。采用单因素和多因素Cox比例危险回归模型识别独立预后因素。另收集江苏省淮安市第一人民医院2019年6月至2020年6月被病理证实的HCC组织及对应的癌旁组织24例,采用随机数字表法将其分为8组,每组3对,采用免疫组织化学染色检测CDCA在HCC及癌旁组织中表达的差异。结果CDCA1-8在HCC标本中表达量高于正常肝组织(P<0.05)。CDCA1/2/5/6/8高表达组总生存率低于低表达组(P<0.05)。CDCA6(HR=1.51,95%CI:1.29~1.75,P<0.001)、CDCA8(HR=1.69,95%CI:1.08~2.64,P<0.05)、年龄(HR=1.03,95%CI:1.01~1.05,P<0.05)、患者肿瘤大小分期[T3(HR=1.46,95%CI:1.47~4.32,P<0.001)、T4(HR=6.61,95%CI:2.84~15.34,P<0.001)]是HCC OS的独立预测因子。结论 CDCA在HCC组织中表达升高,多数CDCA家族成员表达水平与HCC预后显著相关,其中,CDCA6/8是独立预测指标。

SGK1对Cyclin B/Cdc2通路介导小鼠G_(1)期受精卵卵裂的调控作用及其机制

目的:探讨血清和糖皮质激素诱导蛋白激酶1(SGK1)在小鼠细胞周期G_(1)期受精卵早期发育过程中的调控作用,并阐明相关机制。方法:取若干只4~6周龄且体质量约为20 g的雌鼠和若干只8周龄以上且体质量约为30 g的雄鼠,雌鼠腹腔注射孕马血清促性腺激素(PMSG),每只10 IU,48 h后腹腔注射人绒毛膜促性腺激素(HCG),每只10 IU,并将注射HCG的雌鼠与雄鼠1∶1合笼过夜。取交配成功的雌鼠受精卵,注射HCG后分别于12~21 h、21~26 h、26~28 h和28~30 h收集细胞周期G_(1)期、S期、G2期及M期的受精卵,并于光学显微镜下观察不同细胞周期的细胞形态表现。收集小鼠超排卵后G_(1)期受精卵,体外转录生成mRNA后,分为未注射组、Tris-EDTA缓冲液注射组(TE注射组)和SGK1-mRNA注射组。采用SGK1抗体与KSOM培养液配置1∶25、1∶50、1∶100、1∶200和0共5种不同浓度SGK1抗体组的培养液,培养小鼠G_(1)期受精卵。Western blotting法检测各组小鼠受精卵中SGK1蛋白表达水平和各组小鼠及不同浓度SGK1抗体组HCG注射不同时间受精卵中磷酸化细胞分裂周期因子2(Cdc2)酪氨酸15位点(Cdc2-pTyr15)去磷酸化情况,相差显微镜观察各组小鼠和不同浓度SGK1抗体组受精卵发育情况,Western blotting法检测HCG注射不同时间小鼠受精卵中磷酸化SGK1-苏氨酸256位点(SGK1-pThr256)和Cdc2-pTyr15蛋白表达水平。结果:与未注射组和TE注射组比较,SGK1-mRNA注射组SGK1蛋白表达水平明显升高(P<0.01)。HCG注射后27~28 h,SGK1-mRNA注射组小鼠受精卵中Cdc2-pTyr15磷酸化信号逐渐消失,至HCG注射29 h,Cdc2-pTyr15磷酸化信号完全消失;HCG注射后28~29 h,未注射组和TE注射组小鼠受精卵中Cdc2-pTyr15磷酸化信号逐渐消失,至HCG注射后30 h,Cdc2-pTyr15磷酸化信号完全消失;随着SGK1抗体浓度升高,不同浓度SGK1抗体组受精卵中Cdc2-pTyr15磷酸化信号减弱和磷酸化信号消失的时间逐渐延长。HCG注射后27 h,SGK1-mRNA注射组小鼠受精卵开始卵裂;HCG注射后31 h,SGK1-mRNA注射组受精卵几乎全部分裂为G2期细胞受精卵;HCG注射后33 h,0和1∶200 SGK1抗体组受精卵全部发生卵裂;随着SGK1抗体浓度升高,1∶25、1∶50和1∶100 SGK1抗体组受精卵卵裂逐渐减少,在1∶25 SGK1抗体组受精卵卵裂减少最明显。HCG注射后31 h,与未注射组和TE注射组比较,SGK1-mRNA注射组小鼠受精卵死亡率明显降低(P<0.05),卵裂率明显升高(P<0.05)。注射HCG后31和33 h,随着SGK1抗体浓度升高,与1∶200 SGK1抗体组比较,1∶100、1∶50和1∶25SGK1抗体组受精卵死亡率逐渐升高(P<0.05),卵裂时间延长,受精卵卵裂率降低(P<0.05),并呈剂量依赖性,其中1∶25 SGK1抗体组受精卵卵裂率最低。HCG注射后27 h,小鼠受精卵中SGK1-pThr256蛋白表达水平逐渐升高(P<0.05或P<0.01),并呈时间依赖性;HCG注射后28~29 h,小鼠受精卵中Cdc2-pTyr15蛋白表达水平逐渐降低(P<0.01),并呈时间依赖性,并于HCG注射后30 h完全消失。结论:过表达或抑制SGK1均会影响小鼠G_(1)期受精卵进入M期的时间,SGK1蛋白可能是小鼠G_(1)期受精卵早期发育的调控因子之一,其可能通过Cdc2调节G_(1)期受精卵发育。

分裂相关增强子1、细胞分裂周期蛋白25同源蛋白C在直肠癌组织中的表达及其临床意义

目的探讨分裂相关增强子1(Hairy and enhancer of split related protein 1,HESR-1)、细胞分裂周期蛋白25同源蛋白C(Cell division cycle 25C,CDC25C)在直肠癌组织中的表达及其临床意义。方法选择166例行根治性手术的直肠癌患者为研究对象,采用免疫组织化学法检测癌组织及癌旁组织中HESR-1和CDC25C的表达,收集患者临床病理参数并进行随访,分析HESR-1和CDC25C表达对直肠癌患者临床病理参数及预后的影响。结果肠癌组织中CDC25C、HESR-1的阳性率均高于癌旁组织(46.9%vs 12.6%,41.6%vs 7.6%),差异有统计学意义(P<0.05)。在癌组织中,CDC25C mRNA与HESR-1 mRNA的表达呈正相关(r=0.862,P=0.003)。癌组织CDC25C及HESR-1表达阳性患者的肿瘤直径和淋巴结转移率均高于表达阴性者(P<0.05)。Cox多因素分析结果显示,肿瘤直径、淋巴结转移、CDC25C阳性及HESR-1阳性是影响直肠癌患者预后的独立危险因素(P<0.05)。结论HESR-1和CDC25C在直肠癌组织中表达升高,且与患者预后密切相关。

Era蛋白(E.coli ras-like protein)——一个可能参与真、原核细胞信号调控的新分子开关

充足的证据表明:G蛋白作为真核细胞的重要分子开关参与细胞的增殖调控以及部分代谢调控过程。而近年来在大肠杆菌中新发现的Era蛋白(E.coli ras-like protein)则是与已知的三聚体G蛋白和小分子G蛋白不同的一种新的GTP结合蛋白。进一步的研究发现该类GTP结合蛋白不仅存在于原核的大肠杆菌中,而且在高等植物、人类细胞中均含有该蛋白的同源蛋白。大肠杆菌的Era蛋白主要位于细胞膜的内侧,在细胞质中也有一定的分布;真核细胞ERA(ERG)蛋白来源于原核细胞,定位于线粒体或叶绿体上。ERA或ERG蛋白有可能担负着与其它两类G蛋白同样重要的分子开关功能。已有的研究表明,Era蛋白参与调节原核生物的细胞分裂、细胞周期以及部分细胞代谢过程;在哺乳动物细胞中,ERA的同源蛋白可能与细胞周期的G1期调控以及细胞凋亡有关;真核植物中相关研究报道尚少,推测该蛋白可能与种子的正常发育有关。

Asymmetric cell division in plant development

Asymmetric cell division(ACD) is a fundamental process that generates new cell types during development in eukaryotic species.In plant development,post-embryonic organogenesis driven by ACD is universal and more important than in animals,in which organ pattern is preset during embryogenesis.Thus,plant development provides a powerful system to study molecular mechanisms underlying ACD.During the past decade,tremendous progress has been made in our understanding of the key components and mechanisms involved in this important process in plants.Here,we present an overview of how ACD is determined and regulated in multiple biological processes in plant development and compare their conservation and specificity among different model cell systems.We also summarize the molecular roles and mechanisms of the phytohormones in the regulation of plant ACD.Finally,we conclude with the overarching paradigms and principles that govern plant ACD and consider how new technologies can be exploited to fill the knowledge gaps and make new advances in the field.

Era蛋白(E.coli ras-like protein)-一个可能参与真、原细胞信号调控的新分子开关

充足的证据表明G蛋白作为真核细胞的重要分子开关参与细胞的增殖调控以及部分代谢调控过程。而近来在大肠杆菌中新发现的Era蛋白(E.coli ras-like protein)则是与已知的三聚体G蛋白和小分子G蛋白不同的一种新的GTP结合蛋白。进一步的研究发现该类GTP结合蛋白不仅存在于原核的大肠杆菌中,而且在高等植物、人类细胞中均含有该蛋白的同源蛋白。大肠杆菌的Era蛋白主要位于细胞膜的内侧,细胞质中也有一定的分布;一些证据表明,真核细胞ERA(ERG)蛋白来源于原核细胞,定位于线粒体或者叶绿体。近来的研究证据表明ERA或者ERG蛋白有可能担负着与其它两类G蛋白同样重要的分子开关功能。已有的研究表明Era蛋白参与调节原核生物的细胞分裂、细胞周期以及部分细胞代谢过程;在哺乳动物细胞中,同源蛋白ERA可能与细胞周期的G1期调控以及细胞凋亡有关;真核植物中相关研究报道尚少,推测该蛋白可能与种子的正常发育有关。本文主要介绍原核Era蛋白和真核ERA蛋白的结构特点以及功能研究进展。

Changes of NF-kB,p53,Bcl-2 and caspase in apoptosis induced by JTE-522 in human gastric adenocarcinoma cell line AGS cells:role of reactive oxygen species

AIM: To identify whether JTE-522 can induce apoptosis in AGS cells and ROS also involved in the process, and to investigate the changes in NF-kB, p53, bcl-2 and caspase in the apoptosis process. METHODS: Cell culture, MTT, Electromicroscopy, agarose gel electrophoresis, lucigenin, Western blot and electrophoretic mobility shift assay (EMSA) analysis were employed to investigate the effect of JTE-522 on cell proliferation and apoptosis in AGS cells and related molecular mechanisms. RESULTS: JTE-522 inhibited the growth of AGS cells and induced the apoptosis. Lucigenin assay showed the generation of ROS in cells under incubation with JTE-522. The increased ROS generation might contribute to the induction of AGS cells to apoptosis. EMSA and Western blot revealed that NF-kB activity was almost completely inhibited by preventing the degradation of IkBalpha. Additionally, by using Western blot we confirmed that the level of bcl-2 was decreased, whereas p53 showed a great increase following JTE-522 treatment. Their changes were in a dose-dependent manner. CONCLUSION: These findings suggest that reactive oxygen species, NF-kB, p53, bcl-2 and caspase-3 may play an important role in the induction of apoptosis in AGS cells after treatment with JTE-522.

Effect of Nimesulide on proliferation and apoptosis of human hepatoma SMMC-7721 cells

AIM: Cyclooxygenase-2 (COX-2) has been suggested to be associated with carcinogenesis. We sought to investigate the effect of the selective COX-2 inhibitor, Nimesulide on proliferation and apoptosis of SMMC-7721 human hepatoma cells.METHODS: This study was carried out on the culture of hepatic carcinoma SMMC-7721 cell line. Various concentrations of Nimesulide (0, 200 micromol/L, 300 micromol/L, 400 micromol/L) were added and incubated. Cell proliferation was detected with MTT colorimetric assay, cell apoptosis by electron microscopy, flow cytometry and TUNEL.RESULTS: Nimesulide could significantly inhibit SMMC-7721 cells proliferation dose-dependent and in a dependent manner compared with that of the control group. The duration lowest inhibition rate produced by Nimesulide in SMMC-7721 cells was 19.06%, the highest inhibition rate was 58.49%. After incubation with Nimesulide for 72 h, the most highest apoptosis rate and apoptosis index of SMMC-7721 cells comparing with those of the control were 21.20%+/-1.62% vs 2.24%+/-0.26% and 21.23+/-1.78 vs 2.01+/-0.23 (P【0.05). CONCLUSION:The selective COX-2 inhibitor, Nimesulide can inhibit the proliferation of SMMC-7721 cells and increase apoptosis rate and apoptosis index of SMMC-7721 cells. The apoptosis rate and the apoptosis index are dose-dependent. Under electron microscope SMMC-7721 cells incubated with 300 micromol and 400 micromol Nimesulide show apoptotic characteristics. With the clarification of the mechanism of selective COX-2 inhibitors, These COX-2 selective inhibitors can become the choice of prevention and treatment of cancers.

Transcription factor EGR-1 inhibits growth of hepatocellular carcinoma and esophageal carcinoma cell lines

AIM: The transcription factor EGR-1 (early growth response gene-1) plays an important role in cell growth, differentiation and development. It has identified that EGR-1 has significant transformation suppression activity in some neoplasms, such as fibrosarcoma, breast carcinoma. This experiment was designed to investigate the role of egr-1 in the cancerous process of hepatocellular carcinoma (HCC) and esophageal carcinoma (EC), and then to appraise the effects of EGR-1 on the growth of these tumor cells. METHODS: Firstly, the transcription and expression of egr-1 in HCC and EC, paracancerous tissues and their normal counterpart parts were detected by in situ hybridization and immunohistochemistry, with normal human breast and mouse brain tissues as positive controls. Egr-1 gene was then transfected into HCC (HHCC, SMMC7721) and EC (ECa109) cell lines in which no egr-1 transcription and expression were present. The cell growth speed, FCM cell cycle, plate clone formation and tumorigenicity in nude mice were observed and the controls were the cell lines transfected with vector only. RESULTS: Little or no egr-1 transcription and expression were detected in HCC, EC and normal liver tissues. The expression of egr-1 were found higher in hepatocellular paracancerous tissue (transcription level P=0.000; expression level P=0.143, probably because fewer in number of cases) and dysplastic tissue of esophageal cancer (transcription level P=0.000; expression level P=0.001). The growth rate of egr-1-transfected HHCC (HCC cell line) cells and ECa109 (EC cell line) cells was much slower than that of the controls. The proportion of S phase cell, clone formation and tumorigenicity were significantly lower than these of the controls' (decreased 45.5% in HHCC cells and 34.1% in ECa109 cells; 46.6% and 41.8%; 80.4% and 72.6% respectively). There were no obvious differences between SMMC7721 (HCC) egr-1-transfected cells and the controls with regard to the above items. CONCLUSION: The decreased expression of egr-1 might play a role in the dysregulation of normal growth in the cancerous process of HCC and EC. Egr-1 gene of transfected HHCC and ECa109 cells showed obvious suppression of the cell growth and malignant phenotypes, but no suppression in SMMC7721 (HCC cell line) cells.

Effects of epidermal growth factor on the growth of human gastric cancer cell and the implanted tumor of nude mice

AIM: Epidermal growth factor (EGF) plays an important role in the regulation of gastrointestinal tissue growth and development, and it can stimulate epithelial proliferation, cell differentiation and growth. It has been established that the EGF can promote gastric cytoprotection and ulcer healing. But the potential ability of EGF to regulate the gastric cancer growth is unknown. This study is to investigate the influence of EGF on human gastric cancer cell and the implanted tumor growth of nude mice. METHODS: The cell growth rates of human gastric adenocarcinoma cell lines MKN-28, MKN-45, SGC-7901 and normal human gastric epithelial cells 3T3 were assessed when incubated with recombinant human EGF (rhEGF, 0.05, 0.1, 0.5, 1.0, 10, 50, 100 mg.L(-1)) using MTT method. The cells of MKN-28, MKN-45, SGC-7901 (gastric cancer tissue 1.5mm(3)) were implanted in the BALB/cA nude mice for 10 days.The EGF was given intraperitoneally (15, 30, 60 microg.kg(-1)) for 3 weeks. The body weights of the tumor-bearing animals and their tumor mass were measured afterwards to assess the mitogenic effect of rhEGF in the nude mice. RESULTS: Within the concentration range of 0.05-100mg.L(-1), rhEGF could increase the cell growth of normal 3T3 cells (cell growth rate 100% vs 102.8%, P【0.05), but partially restrain the gastric cancer cell growth. The latter effect was related to cell differentiation. In 15-60 microg/kg rhEGF groups, the mean implanted tumor mass of MKN-28 cell were 1.75 g, 1.91 g, 2.08 g/NS group 1.97 g (P】0.05), the mean tumor mass of SGC-7901 cell were 1.53 g, 1.07 g, 1.20 g/NS group 1.07 g (P】0.05), and for MKN-45 cell, the tumor mass were respectively 1.92 g, 1.29 g, 1.77 /NS group 1.82 g (P】0.05). So rhEGF had no obvious effect on implanted MKN-28, SGC-7901 and MKN-45 tumor growth. CONCLUSION: EGF has no stimulating effect on the human gastric cancer cell growth neither in vitro nor in vivo.