小檗碱对链脲菌素和高糖高脂饲料诱导糖尿病大鼠骨骼肌CDK9和cyclin T1表达的影响

目的观察小檗碱对2型糖尿病大鼠骨骼肌病理结构改变及CDK9和cyclin T1蛋白表达的影响。方法腹腔注射链脲菌素(35 mg·kg~(-1))加高糖高脂饲料喂养16 wk建立2型糖尿病大鼠模型,随后16 wk每天分别拌食给予低中高剂量小檗碱(75、150、300 mg·kg~(-1))、非诺贝特(100 mg·kg~(-1))和罗格列酮(4 mg·kg~(-1)),用HE染色检查骨骼肌结构病变和免疫组化检测CDK9和cyclin T1的表达。结果骨骼肌纤维在各组大鼠中仍正常分布,中高剂量小檗碱部分地改善糖尿病肌纤维的萎缩;中高剂量小檗碱和罗格列酮都能明显恢复糖尿病大鼠骨骼肌中表达降低的CDK9和cyclin T1至正常水平(P<0.01)。结论小檗碱调控骨骼肌CDK9和cyclin T1蛋白的表达可能是其改善糖尿病骨骼肌纤维萎缩的机制之一。     

宫颈癌组织中CDC6、CDK1的表达及其与HPV16／18感染的相关性研究

目的：研究CDC6、CDK1在宫颈癌组织中的表达及其与HPV16/18感染的相关性，以探讨宫颈癌的发生机制，进一步寻找宫颈癌诊断的新的分子标志物。方法：采用免疫组织化学方法对50例宫颈癌石蜡标本、宫颈上皮内瘤样病变CINI20例、CINⅡ-Ⅲ20例、正常宫颈组织20例进行CDC6、CDK1的检测，同时采用PCR技术检测HPV16/18感染情况。结果：在宫颈癌组织中CDC6、CDK1的阳性率高于CIN和正常宫颈组织，差异有显著性（均P〈0．05），且CDC6、CDKl阳性表达率与病理分级有关，差异有显著性（均P〈0．05），CDC6阳性表达率均与淋巴结转移有关（P〈0．05）；CDK1阳性表达率均与淋巴结转移无关（P〉0．05）；在宫颈癌组织中CDC6和CDK1的阳性表达率与年龄、临床分期无关（均P〉0．05）。HPV16/18在正常宫颈组织、CIN和宫颈癌中的阳性率逐渐升高，差异有显著性（P〈0．05），但与临床分期、病理分级、淋巴转移、年龄无关（均P〉0．05）。CDK1和CDC6的表达有正相关性（L=0．529，P〈0．05）；CDC6与HPV16/18感染有关（r=0．386，P〈0．05）；CDK1与HPV16/18感染无关（rs=0．145，P〉0．05）。结论：宫颈上皮内瘤样病变及宫颈癌组织中CDC6表达的改变可能与HPV16/18感染有关，且互相作用，共同影响CIN的发展及宫颈癌的发生。这些指标综合分析可能为阐明HPV16/18的恶性转化机制以及为提高宫颈癌及其癌前病变诊断率提供参考依据。CDC6、CDK1的异常表达与宫颈癌的恶变程度有关，可作为宫颈癌筛查、预后判断的有用指标。     

骨肉瘤中Rb、p16、CDK4、cyclinD1蛋白的表达及其意义

目的 探讨骨肉瘤中Ｒｂ、ｐ１６、ＣＤＫ４、ｃｙｃｌｉｎＤ１的蛋白表达、相互关系及其意义。方法 应用免疫组化方法对４０例骨肉瘤组织中Ｒｂ、ｐ１６、ＣＤＫ、ｃｙｃｌｉｎＤ１的蛋白表达状况进行检测。结果 ４０例骨肉瘤Ｒｂ、ｐ１６蛋白表达缺失分别为７２．５％（２９／４０和）２２．５％（９／４０）;１１例ｐＲｂ阳性的骨肉瘤中的８例ｐ１６阴性,２９例ｐＲｂ阴性的骨肉瘤中２８例ｐ１６阳性;５２．５％（２１／４０     

A new structural class of proteasome inhibitors identified by microbial screening using yeast-based assay

A yeast-based growth interference assay was developed utilizing a yeast strain in which expression of Xenopus cyclin A1 was induced to elevate cell division cycle 28 (Cdc28) kinase activity. Since the hyperactivation of Cdc28 kinase in yeast results in a growth-arrest phenotype, compounds which could rescue the cyclin A1-induced growth arrest might be potential new, antitumor drug candidates acting on the cyclin-dependent, kinase-mediated, cell cycle regulation pathway. In the course of our microbial screening program, the new Streptomyces metabolites, belactosins, were identified. As reported previously, belactosin A induced cell cycle arrest at G2/M phase in human cancer cells. However, the molecular mechanism of action was unknown. We herein demonstrate the proteasome inhibition by belactosin A. Belactosin A did not inhibit yeast Cdc28 kinase and human cyclin-dependent kinase in vitro. On the other hand, it inhibited the chymotrypsin-like activity of the rabbit 20S proteasome. From the initial SAR studies, we identified a hydrophobic belactosin A derivative, KF33955, which exhibited a 100-fold greater growth-inhibitory activity against HeLa S3 cells than belactosin A, presumably due to its higher cell permeability. The biochemical analysis using KF33955 suggested that the proteasome inhibitory activity of KF33955 were irreversible and required the beta-lactone moiety to inhibit the proteasome. KF33955 increased the intracellular levels of protein ubiquitination in NIH3T3 cells. In addition, KF33955 treatment resulted in the accumulation of known proteasome substrates in HeLa S3 cells. These results identify belactosin A as a useful lead compound to target proteasome for the treatment of disease whose etiology is dependent on the unregulated ubiquitin-proteasome pathway.     

Induction of G1 phase arrest in MCF human breast cancer cells by pentagalloylglucose through the down-regulation of CDK4 and CDK2 activities and up-regulation of the CDK inhibitors p27(Kip) and p21(Cip)

Pentagalloylglucose (5GG) is a potent and specific inhibitor of NADPH dehydrogenase or xanthine oxidase. In our previous study, we showed that 5GG was able to induce apoptosis in HL-60 cells in a time- and concentration-dependent manner via the activation of caspase-3. Recently, we found that 5GG was capable of perturbing the cell cycle of the human breast cancer cell line MCF-7. DNA flow cytometric analysis showed that 5GG exhibited the ability of blocking MCF-7 cell cycle progression at the G1 phase. The level of several G1 phase-related cyclins and cyclin-dependent kinases did not change in these cells during a 24-hr exposure to 5GG. However, the activity of cyclin E/CDK2 was decreased in a concentration- and time-dependent manner and the activity of cyclin D/CDK4 was inhibited when serum-starved synchronized cells were released from synchronization. p27(Kip) and p21(Cip), inhibitors of cyclin/CDK complexes in G1-phase, were gradually increased after 5GG treatment in a time-dependent manner and the induction of p21(Cip) was correlated with an increase in p53 levels. These results suggest that the suppression of cell-cycle progression in the G1 phase by 5GG was mediated in MCF-7 cells, at least in part, by either the inhibition of cyclin D/CDK4 and cyclin E/CDK2 activity or the induction of the CDK inhibitors p27(Kip) and p21(Cip).     

瑞香狼毒药效组分诱导人肝癌细胞凋亡及对细胞周期依赖性蛋白激酶CDK2的影响

目的:探讨瑞香狼毒药效组分Zp1111对人肝癌细胞的增殖抑制与诱导凋亡作用及机制。方法:MTT法比较瑞香狼毒药效组分Zp1111对体外培养的人来源肝癌细胞与正常肝细胞LO2抑制作用,采用流式细胞术检测用药前后BEL-7402细胞凋亡的变化并分析Zp1111对DNA周期分布的影响,荧光共振能量转移法检测Zp1111对细胞周期依赖性蛋白激酶CDK2的抑制作用。结果:Zp1111对体外培养的肝癌细胞HepG2、BEL-7402、SMMC-7721均有较好的抑制作用,IC50分别为37.75μg/ml、28.60μg/ml、29.22μg/ml,而对正常肝细胞LO2抑制作用不明显,在25μg/ml及以下的浓度对LO2细胞反而有一定促进作用。Zp1111能诱导BEL-7402细胞发生凋亡,一定药物浓度范围内凋亡率具有药物浓度依赖关系;Zp1111还能调控体外培养的BEL-7402细胞周期分布,显著下调S期的细胞比例,并且对CDK2具有较好的抑制作用。结论:瑞香狼毒药效组分Zp1111具有一定诱导凋亡作用,可使BEL-7402细胞周期阻滞在G1期,其作用机制可能与抑制CDK2有关。     

An Embryonic Diapause-like Adaptation with Suppressed Myc Activity Enables Tumor Treatment Persistence

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卵巢上皮性癌组织中细胞周期素B1和CDK1的表达

目的:探讨卵巢上皮性癌组织中细胞周期素B1(CyclinB1)和细胞周期蛋白依赖性激酶1(CDK1)的表达及其意义。方法:应用免疫组化SP法检测20例正常卵巢组织、20例卵巢良性上皮性肿瘤组织、40例卵巢上皮性癌组织中CyclinB1和CDK1蛋白的表达。结果:①卵巢上皮性癌组织中CyclinB1和CDK1蛋白的阳性表达率分别为77.5%和90.0%,良性卵巢上皮肿瘤组织分别为25.0%和35.0%,正常卵巢组织分别为5.0%和10.0%,3者相比差异有统计学意义(χ2=33.036,39.568;P<0.001)。②CyclinB1蛋白的表达与卵巢上皮性癌FIGO分期、组织分化和淋巴结转移有关(P<0.05),CDK1蛋白的表达与卵巢上皮性癌临床病理特征无关。结论:CyclinB1和CDK1蛋白在卵巢上皮性癌组织中存在异常高表达,可能在卵巢上皮性癌的早期恶变过程中发挥重要作用。     

黄连素对脑缺血再灌注后细胞cyclin D1、CDK4表达的影响

目的 探讨黄连素对大鼠局灶性脑缺血再灌注后脑组织CDK4和cyclin D1表达的调节以及黄连素可能的脑保护作用机制.方法 50只雄性Wistar大鼠按照随机数字表法分为给药组(n=15)、正常组(n=5)、假手术组(n=15)和模型组(n=15).用线栓法建立局灶性脑缺血模型,缺血 1 h后再灌注1 d,3 d,5 d,用HE染色观察缺血再灌注后脑组织的形态学变化,免疫组化方法 检测缺血中心区和半暗带Bcl-2、cyclin D1和CDK4的表达.结果 HE染色显示给约组3 d和5 d动物脑组织半暗带神经元数目丢失少于模型组.免疫组化表明给药组1 d与模型组比较Bcl-2免疫阳性细胞数没有明显区别,给药组3 d和5 d与模型组比较,半暗带Bcl-2免疫阳性细胞增加,差异有统计学意义(P＜0.05),但cyclin D1与CDK4免疫阳性细胞减少.结论大鼠局灶性脑缺血时,黄连素抑制半暗带神经元细胞周期蛋白cyclin D1与CDK4的表达,表明黄连素可能具有一定的神经保护作用.其可能机制为通过抑制cyclin D1的表达,并阻止其从细胞质转入细胞核内,从而阻断级联反应,抵抗cyclin D1介导的细胞凋亡.