桔青霉No.68菌株的发酵产物对微管作用的研究

在寻找作用于微管的微生物活性代谢产物的过程中,发现从东北红豆杉内皮层中分离到的一株枯青霉菌Ｎｏ．６８的发酵液能将细胞有丝分裂阻断在中期,通过免疫荧光试验和电镜观察。证明发酵液中含有作用于微管的活性物质,且其作用效果为抑制微管聚合。     

CHFR基因与消化道肿瘤关系的研究进展

CHFR(checkpoint with FHA and ring finger),一种在人类癌症中灭活的新的细胞周期检查点基因,在有丝分裂应激时,延迟染色体的浓集、阻止细胞进入有丝分裂中前期.研究表明,CHFR在爪蟾中是P1k1的泛素连接酶,在哺乳动物细胞中主要通过抑制Cyclin B_1进入细胞核、调节Aurora-A的水平及与P38应激激酶相互作用,阻止细胞进入有丝分裂前期.USP7介导的CHFR去泛素化致其累积可能对于CHFR激活是一个关键的调节步骤.在消化道肿瘤中,CHFR表达由于CPG岛甲基化而沉默.本文对CHFR基因的结构、编码蛋白的功能及其与消化道肿瘤关系的研究进展作一综述.     

Identification of fibroblast growth factor-8b target genes associated with early and late cell cycle events in breast cancer cells

Fibroblast growth factor-8 (FGF-8) is implicated in the development and progression of breast cancer and its levels are frequently elevated in breast tumors. The mechanisms driving FGF-8-mediated tumorigenesis are not well understood. Herein we aimed to identify target genes associated with FGF-8b-mediated breast cancer cell proliferation by carrying out a cDNA microarray analysis of genes expressed in estrogen receptor negative S115 breast cancer cells treated with FGF-8b for various time periods in comparison with those expressed in non-treated cells. Gene and protein expression was validated for selected genes by qPCR and western blotting respectively. Furthermore, using TRANSBIG data, the expression of human orthologs of FGF-8-regulated genes was correlated to the Nottingham prognostic index and estrogen receptor status. The analysis revealed a number of significantly up- and down-regulated genes in response to FGF-8b at all treatment times. The most differentially expressed genes were genes related to cell cycle regulation, mitosis, cancer, and cell death. Several key regulators of early cell cycle progression such as Btg2 and cyclin D1, as well as regulators of mitosis, including cyclin B, Plk1, survivin, and aurora kinase A, were identified as novel targets for FGF-8b, some of which were additionally shown to correlate with prognosis and ER status in human breast cancer. The results suggest that in stimulation of proliferation FGF-8b not only promotes cell cycle progression through the G1 restriction point but also regulates key proteins involved in chromosomal segregation during mitosis and cytokinesis of breast cancer cells.     

二乙基亚硝胺诱发肝癌前病变大鼠模型的建立

目的:研究二乙基亚硝胺诱发大鼠肝癌前病变的时效关系与量效关系.方法:Wistar♂大鼠100只,体质量均衡随机分5组;每84h1次分别腹腔注射二乙基亚硝胺0、25、50、75、100mg/kg造模.每组体质量排序分10小组,年龄配对;造模时程最短0d,间隔14d延长,最长126d,灌注固定肝脏.常规石蜡包埋,6μm切片,HE染色,观察病变性质后显微照相;使用Image-Pro Plus软件,分别形态计量10、20、40倍物镜下汇管区(R1)、肝索(R2)、肝细胞核(R3)的体积构成比,观察每10个高倍镜视野下的核分裂像;计算各动物异型性指数[Ei=(1-R1)-1·(R3)·(R2)-1].Prism 4软件回归"二乙基亚硝胺导致异型性指数"的时效曲线及曲线下面积,进而导致曲线下面积的量效关系.结果:以异型性指数(肝细胞核/浆体积比校正值),回归0、25、50、75、100mg/kg二乙基亚硝胺造模的半效时程(95%CI)分别为70347(0-)、1734(937-3211)、1536(948-2490)、1530(890-2632)、1183(955-1466)h,曲线下面积分别为0.0064、0.0084、0.0123、0.0165、0.0167[异型性指数·log(h)].以曲线下面积,回归二乙基亚硝胺诱发肝细胞癌前病变的半效剂量为48.255mg/kg.50.000mg/kg造模各时程的异型性指数与核分裂像总数之间呈直线正相关(y=0.0023x-0.0056,r=0.9217,n=10,P<0.01).结论:以异型性指数为指标,每84h腹腔注射1次二乙基亚硝胺,诱发♂大鼠肝细胞癌前病变的最佳造模剂量为48.255mg/kg(约50.000mg/kg),最佳造模累积连续时程为64d.核分裂像计数验证了异型性指数的临床预警价值.     

布氏姜片吸虫染色体组型分析

采用气干法研究布氏姜片吸虫染色体组型,发现与前人报道的不同。其二倍体染色体数为2n=14,染色体包括大、中、小三型,其中具中部着丝点的(m)4对,具亚中部着丝点的(sm)2对,具端部着丝点的(t)1对。各染色体对的相对长度、臂指数及着丝点指数与前人报道的数据进行了t检验分析,发现第3、4、6对染色体在臂指数及着丝点指数上有非常显著的差异(P<0.01)     

石蒜碱内铵盐对小鼠艾氏腹水癌细胞周期及核分裂的影响

石蒜碱内铵盐是一种有效的抗癌物质,本工作以荧光激活细胞分类器方法证明,它在治疗剂量40mg/kg时能使G_1期细胞百分比下降,G_2+M期细胞明显上升,对G_2期细胞向G_1期的过渡有阻滞作用。在给药后8～72h使癌细胞有丝分裂指数明显下降。至第6d趋向恢复。此药对早期和中期细胞分裂象的抑制作用较强,尤其在用药后8h为最显著,对晚期、末期的作用不明显。     

Peculiar pattern of interkinetic nuclear migration in the newt Notophtalmus viridescens

Summary The distribution of mitotic figures was studied in the neuroepithelium of Notophtalmus viridescens embryos of stages 14, 16 and 18. On the average, 34% of the mitotic figures were counted near the neurocoele (here in described as zone 1), 10% were recorded in the outer portion of the epithelium (zone 3) and 56% were found between these two regions (zone 2). It is concluded that this neuroepithelium is the site of interkinetic nuclear migration although its pattern is peculiar when compared to what occurs in the chick embryo. Also, the analysis of one micron-thick serial sections showed that the neuroepithelium in Notophtalmus viridescens is pseudo-stratified throughout neurulation.

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Resumé On a étudié la distribution des figures mitotiques dans le neuroépithélium d'embryons de Notophtalmus viridescens arrivés aux stades 14, 16 et 18. En moyenne, 34% des figures mitotiques apparaissaient près du neurocoele (ici décrite comme zone 1), 10% occupaient la zone externe de l'épithélium (zone 3) et 56% se trouvaient entre ces deux régions (zone 2). Il en est conclu que ce neuroépithélium est le site d'une migration nucléaire intercinétique qui est cependant d'un type particulier lorsqu'on la compare à ce qui s'observe chez l'embryon de poulet. De plus, l'étude de coupes sériées d'un micron d'épaisseur a permis de montrer que chez Notophtalmus viridescens, le neuroépithélium est pseudostratifié pendant toute la durée de la neurulation.

     

KIF14在恶性肿瘤中的研究进展

KIF14作为驱动蛋白超家族(KIFS)中的成员,通过调节有丝分裂纺锤体的形成、染色体的分离和胞质分裂的完成,从而促进肿瘤的发生和发展.KIF14的异常已经在人类多种恶性肿瘤中得到证实,其作用的增强可影响有丝分裂的进程而导致肿瘤的发生;其作用降低可导致Akt激酶失活,从而降低细胞的迁移,促进细胞的凋亡.此外,KIF14的缺失也可增强肿瘤对化疗的敏感性.综上所述,KIF14在肿瘤的发生发展过程中起到了重要作用,本文就KIF14与恶性肿瘤的关系做一综述.     

Small-molecule inhibition of Aurora kinases triggers spindle checkpoint-independent apoptosis in cancer cells

Aurora kinases are key regulators of mitotic progression and have also been implicated in tumorigenesis. Small molecules that inhibit Aurora kinases have shown impressive anticancer activity in preclinical studies and are currently under clinical evaluation. In this study, our data show that suppression of Aurora activity with a specific inhibitor prevents the proliferation of breast cancer cells. Molecular modeling studies indicate that the Aurora inhibitor suppresses Aurora activity by competitive displacement of ATP. Mechanistically, the Aurora inhibitor causes the accumulation of multinucleated cells, leading to profound apoptosis in the absence of caspase-3 activity. Further studies show that the sensitivity of cancer cells to the Aurora inhibitor is independent of the spindle checkpoint. In addition, the Aurora inhibitor acts synergistically with the vinca alkaloids but not with the taxanes in inhibiting cell proliferation and inducing apoptosis. These results suggest that Aurora inhibitors might be effective in spindle checkpoint-defective cancer cells and a combination of Aurora inhibitors with the vinca alkaloids is a promising approach for cancer chemotherapy.     

Characterization of the biological activity of a potent small molecule Hec1 inhibitor TAI-1

Background

Hec1 (NDC80) is an integral part of the kinetochore and is overexpressed in a variety of human cancers, making it an attractive molecular target for the design of novel anticancer therapeutics. A highly potent first-in-class compound targeting Hec1, TAI-1, was identified and is characterized in this study to determine its potential as an anticancer agent for clinical utility.

Methods

The in vitro potency, cancer cell specificity, synergy activity, and markers for response of TAI-1 were evaluated with cell lines. Mechanism of action was confirmed with western blotting and immunofluorescent staining. The in vivo potency of TAI-1 was evaluated in three xenograft models in mice. Preliminary toxicity was evaluated in mice. Specificity to the target was tested with a kinase panel. Cardiac safety was evaluated with hERG assay. Clinical correlation was performed with human gene database.

Results

TAI-1 showed strong potency across a broad spectrum of tumor cells. TAI-1 disrupted Hec1-Nek2 protein interaction, led to Nek2 degradation, induced significant chromosomal misalignment in metaphase, and induced apoptotic cell death. TAI-1 was effective orally in in vivo animal models of triple negative breast cancer, colon cancer and liver cancer. Preliminary toxicity shows no effect on the body weights, organ weights, and blood indices at efficacious doses. TAI-1 shows high specificity to cancer cells and to target and had no effect on the cardiac channel hERG. TAI-1 is synergistic with doxorubicin, topotecan and paclitaxel in leukemia, breast and liver cancer cells. Sensitivity to TAI-1 was associated with the status of RB and P53 gene. Knockdown of RB and P53 in cancer cells increased sensitivity to TAI-1. Hec1-overexpressing molecular subtypes of human lung cancer were identified.

Conclusions

The excellent potency, safety and synergistic profiles of this potent first-in-class Hec1-targeted small molecule TAI-1 show its potential for clinically utility in anti-cancer treatment regimens.