CyclinE和p27蛋白在骨肉瘤中的表达及临床意义

目的探讨CyclinE和p27在骨肉瘤中表达及临床意义。方法检测108例骨肉瘤石蜡包埋组织中CyclinE和p27蛋白表达水平,统计分析其与患者临床病理因素和预后之间的关系。结果骨肉瘤组织中CyclinE的阳性率为68．52％,p27的阳性率为26．85％;CyclinE和p27蛋白表达水平与骨肉瘤病理分级、软组织浸润、远处转移、Enneking分期及患者整体生存期有关（P〈0．05）;CyclinE蛋白阳性组骨肉瘤患者5年存活率显著低于阴性组;而p27蛋白阳性组患者5年存活率显著高于阴性组（P〈0．05）。Cox多因素分析提示软组织浸润及远处转移状态、病理分级、Enneking外科分期、CyclinE和p27蛋白表达水平是影响骨肉瘤患者预后的独立危险因素（P〈0．05）。结论CyclinE和p27蛋白表达水平是判断骨肉瘤患者预后的新指标,联合检测CyclinE和p27蛋白表达水平对骨肉瘤的进展、预后判断有重要意义。     

Cell cycle independent role of Cyclin E during neural cell fate specification in Drosophila is mediated by its regulation of Prospero function

During development, neural progenitor cells or neuroblasts generate a great intra- and inter-segmental diversity of neuronal and glial cell types in the nervous system. In thoracic segments of the embryonic central nervous system of Drosophila, the neuroblast NB6-4t undergoes an asymmetric first division to generate a neuronal and a glial sublineage, while abdominal NB6-4a divides once symmetrically to generate only 2 glial cells. We had earlier reported a critical function for the G1 cyclin, CyclinE (CycE) in regulating asymmetric cell division in NB6-4t. Here we show that (i) this function of CycE is independent of its role in cell cycle regulation and (ii) the two functions are mediated by distinct domains at the protein level. Results presented here also suggest that CycE inhibits the function of Prospero and facilitates its cortical localization, which is critical for inducing stem cell behaviour, i.e. asymmetric cell division of NB6-4t. Furthermore our data imply that CycE is required for the maintenance of stem cell identity of most other neuroblasts.     

细胞周期调控因子在肺癌活检组织中的表达

目的：探讨P^21waf1和CyclinE在肺鳞癌组织中表达,方法：应用细胞周期调控因子P^21waf1、CyclinE单克隆抗体,对54例肺鳞状细胞的纤支镜活检标本和10例正常肺组织进行免疫组化染色研究。结果：在肺鳞癌组织中P^21waf1呈低水平表达,其阳性表达率（11／54）仅为20．4％,在肺鳞癌组织中CyclinE阳性表达率（17／54）为31．5％,低分化及有淋巴结转移的病例,其CyclinE表达量明显高于高中分化及无淋巴结转移的病例。结论：P^21waf1在肺鳞癌组织中呈低表达,CyclinE表达可以作为判断肺鳞癌恶性程度的一个指标。     

Nuclear accumulation of epidermal growth factor receptor and acceleration of G1/S stage by Epstein-Barr-encoded oncoprotein latent membrane protein 1

Epstein-Barr virus (EBV)-encoded latent membrane protein 1 (LMP1) is considered to be the major oncogenic protein of EBV-encoded proteins and has always been the core of the oncogenic mechanism of EBV. Advanced studies on nuclear translocation of the epidermal growth factor receptor (EGFR) family have greatly improved our knowledge of the biological function of cell surface receptors. In this study, we used the Tet-on LMP1 HNE2 cell line as a cell model, which is a dual-stable LMP1-integrated nasopharyngeal carcinoma (NPC) cell line and the expression of LMP1 which could be regulated by the Tet system. We found that LMP1 could regulate the nuclear accumulation of EGFR in a dose-dependent manner quantitatively and qualitatively. We also demonstrated that the nuclear localization sequence of EGFR played some roles in the location of the protein within the nucleus under LMP1 regulation and EGFR in the nucleus could bind to the promoters of cyclinD1 and cyclinE, respectively. We further demonstrated that EGFR is involved in the acceleration of the G1/S phase transition by LMP1 through binding to cyclinD1 and cyclinE directly. These findings provided a novel view that the acceleration of LMP1 on the G1/S transition via the nuclear accumulation of EGFR was critical in the process of nasopharyngeal carcinoma.     

基于肝癌CDK2 基因敲减对CyclinE 表达及树舌多糖GF对其影响的研究

目的:探究树舌多糖GF(GAPS.GF)对rAAV-shRNA-CDK2抑制肝癌细胞Cyclin E基因表达的辅助作用。方法:将细胞培养后的人肝癌HepG2以皮下注射的方式接种于裸鼠前肢腋下,接种后的裸鼠随机分为5组:NC(非相关序列)对照组、肿瘤组、rAAV-shRNA-CDK2组、树舌多糖GF组以及树舌多糖GF+rAAV-shRNA-CDK2组,各实验组均采取尾静脉注射定量给药。采用实时定量PCR和Western blot技术研究肝癌细胞Cyclin E基因m RNA和蛋白水平的表达情况,同时观察GASP.GF对其作用的影响。结果:树舌多糖GF+rAAV-shRNA-CDK2联合应用组对肝癌HepG2细胞增殖的抑瘤率为75.6%,对Cyclin E基因mRNA表达抑制率为69%,对Cyclin E基因蛋白表达抑制率为67.5%,比rAAV-shRNA-CDK2组分别提高了3.42%、1%和2.7%。结论:树舌多糖GF与rAAV-shRNA-CDK2联合应用可以显著提高肝癌的治疗效果,说明树舌多糖GF可以辅助r AAV-shRNACDK2对肝癌细胞Cyclin E基因的表达的抑制作用。     

MAP kinase dependent cyclinE/cdk2 activity promotes DNA replication in early sea urchin embryos

Sea urchins provide an excellent model for studying cell cycle control mechanisms governing DNA replication in vivo. Fertilization and cell cycle progression are tightly coordinated by Ca²⁺ signals, but the mechanisms underlying the onset of DNA replication after fertilization remain less clear. In this study we demonstrate that calcium-dependent activation of ERK1 promotes accumulation of cyclinE/cdk2 into the male and female pronucleus and entry into first S-phase. We show that cdk2 activity rises quickly after fertilization to a maximum at 4 min, corresponding in timing to the early ERK1 activity peak. Abolishing MAP kinase activity after fertilization with MEK inhibitor, U0126, substantially reduces the early peak of cdk2 activity and prevents cyclinE and cdk2 accumulation in both sperm pronucleus and zygote nucleus in vivo. Both p27^kip1 and roscovitine, cdk2 inhibitors, prevented DNA replication suggesting cdk2 involvement in this process in sea urchin. Inhibition of cdk2 activity using p27^kip1 had no effect on the phosphorylation of MBP by ERK, but completely abolished phosphorylation of retinoblastoma protein, a cdk2 substrate, indicating that cdk2 activity is downstream of ERK1 activation. This pattern of regulation of DNA synthesis conforms to the pattern observed in mammalian somatic cells.