TEP1,CDK4在膀胱癌中的表达及意义

目的:研究TEP1和CDK4蛋白在膀胱癌中的表达及其生物学意义。方法:采用免疫组化SP法,测定10例正常膀胱粘膜及40例膀胱移行细胞癌(BTCC)标本中的TEP1,CDK4蛋白的表达。结果:TEP1和CDK4蛋白在膀胱癌中的表达与在正常膀胱粘膜比较差异均有显著性(P<0.05)。不同临床分期间TEP1和CDK4表达的差异均具有显著性意义(P<0.05);不同病理分级间TEP1表达的差异具有显著性意义(P<0.05),CDK4表达的差异无显著性意义(P>0.05);TEP1和CDK4蛋白的表达无相关(r=-0.3394,P>0.05)。结论:TEP1表达缺失及CDK4的过度表达可能在膀胱癌的发生,发展中具有重要作用,TEP1,CDK4蛋白可成为反映膀胱癌恶性程度及预后估计的参考指标。     

Monensin-mediated growth inhibition in acute myelogenous leukemia cells via cell cycle arrest and apoptosis

Monensin, an Na(+) ionophore, regulates many cellular functions including apoptosis. However, there has been no report about the antitumoral effect of monensin on acute myelogenous leukemia (AML). Here, we investigated the antiproliferative effect of monensin on AML cells in vitro and in vivo. Monensin efficiently inhibited the proliferation of all of 10 AML cell lines, with IC(50) of about 0.5 microM. DNA flow cytometric analysis indicated that monensin induced a G(1) and/or a G(2)-M phase arrest in these cell lines. To address the mechanism of the antiproliferative effect of monensin, we examined the effect of monensin on cell cycle-related proteins in HL-60 cells. The levels of CDK6, cyclin D1 and cyclin A were decreased. In addition, monensin not only increased the p27 level but also enhanced its binding with CDK2. Furthermore, the activities of CDK2- and CDK6-associated kinases reduced by monensin were associated with hypophosphorylation of Rb protein. Monensin also induced apoptosis in AML cells including HL-60 cells. The apoptotic process of HL-60 cells was associated with changes in Bax, caspase-3, caspase-8 and mitochondria transmembrane potential (Deltapsi(m)). In particular, monensin (i.p. at a dose of 8 mg/kg thrice weekly) significantly reduced the tumor size of BALB/c mice that were inoculated s.c. with its derived cell line, WEHI-3BD cells (69% growth inhibition relative to control group; p < 0.05). Tumors from monensin-treated mice exhibited increased apoptosis, and these tumor were immunohistochemically more stained with Bax, Fas and p53 antibodies than control tumors. In conclusion, this is the first report that monensin potently inhibits the proliferation of AML cells.     

Cyclin D1和CDK4正性调节苯并(a)芘所致人胚肺成纤维细胞周期改变

目的研究苯并(a)芘[B(a)P]对人胚肺成纤维细胞(HELF)的细胞周期分布及细胞周期蛋白D1(cyclin D1)和细胞周期蛋白依赖激酶4(CDK4)蛋白表达的影响,并探讨两种蛋白含量改变与细胞周期效应之间的关系。方法将反义cyclin D1质粒和反义CDK4质粒导入HELF细胞内,建立两种质粒稳定转染的细胞模型。用0.1、0.5、2.5和12.5μmol/L的B(a)P处理HELF细胞24h,用蛋白印迹方法检测cyclin D1和CDK4蛋白表达水平;利用流式细胞技术检测B(a)P处理对HELF细胞及两种稳定转染细胞系细胞周期的影响。结果成功建立了反义cyclin D1和反义CDK4稳定转染的细胞系。不同剂量B(a)P处理可引起cyclin D1蛋白表达的显著增加,但对CDK4蛋白表达无明显影响;2.5μmol/L的B(a)P处理HELF细胞24h后,引起其细胞周期G1期显著下降,S期显著增加;2.5μmol/L的B(a)P处理反义cyclin D1和反义CDK4稳定转染的HELF细胞24h后,对其细胞周期的分布无显著影响。结论Cyclin D1和CDK4基因均参与了B(a)P所致细胞周期改变过程,并发挥正性调节作用。     

P53、P21 WAF1和CDK4在胰腺癌组织中的表达

目的研究胰腺癌中P53、P21WAF1和CDK4的表达意义及其相互关系,探讨PCNA的评分和P53、P21WAF1、CDK4表达的关系。方法应用免疫组织化学二步法检测P53、P21WAF1、CDK4和PCNA在48例胰腺癌和14例慢性胰腺炎中的表达。结果胰腺癌组织中P53、P21WAF1、CDK4的阳性表达率分别是56.25%(27/48)、52.08%(25/48)、62.50%(30/48),同慢性胰腺炎组相比较P53、CDK4的表达明显升高(P<0.01),而P21WAF1的表达明显降低(P<0.01);高分化、无淋巴结转移、临床分期I、II期的胰腺癌组织中P21WAF1的阳性表达率明显高于低分化、有淋巴结转移、临床分期Ⅲ、Ⅳ期的胰腺癌(P<0.05);而CDK4则相反(P<0.05);有淋巴转移的胰腺癌组织中P53的表达明显高于无淋巴转移的组织(P<0.05)。结论P53、CDK4的过表达和P21WAF1的缺失表达通过P53和(或)P21WAF1和(或)CDK4途径在胰腺癌的发生、发展过程中起重要的协同作用。三者与胰腺癌细胞的增殖有关,影响胰腺癌生物学行为。     

Fluspirilene下调Akt抗肝癌的分子机制研究

目的探索小分子化合物Fluspirilene下调Akt抗肝癌的分子机制。方法细胞实验:经不同浓度Fluspirilene处理肝癌细胞HepG2和Huh7后,通过mRNA转录组筛查检测差异表达;Western blot实验检测蛋白表达水平。动物实验:经不同浓度Fluspirilene处理肝癌移植瘤模型小鼠21 d后取肿瘤组织,通过免疫组化检测蛋白水平的表达。结果与对照之间相比,Fluspirilene处理组mRNA转录组筛查显示Akt呈现3.07倍低表达(P<0.01)。免疫组化蛋白检测Fluspirilene治疗肝癌移植瘤小鼠组,其组织p-Akt蛋白水平呈现浓度依赖性低表达(P<0.05)。Western blot蛋白水平检测结果:p-Akt、p-CDK2及p-Rb蛋白水平呈现浓度依赖性低表达(P<0.05)。结论通过体内外生物分子实验推测Fluspirilene通过调控Akt激酶,降低细胞周期蛋白依赖性激酶CDK2、Rb的活性发挥抗肝癌作用。     

MDM2 and CDK4 expression in carcinosarcoma of the esophagus: comparison with squamous cell carcinoma and review of the literature

Certain tumors of the esophagus that display both sarcomatous and carcinomatous features have long been recognized. The nomenclature, classification, and histogenesis remain controversial and the microscopic differential diagnosis from other esophageal malignancies can be challenging, particularly in small biopsies. In this paper, we review the literature of carcinosarcoma and present two cases of esophageal carcinosarcoma, describing their salient histologic, immunohistochemical, and ultrastructural features. Also, we assess the expression of MDM2 and CDK4 in the carcinomatous and sarcomatous compartments of our cases and we compare them with the expression of these oncogenes in selected cases of esophageal squamous cell carcinoma with prominent stromal reaction. In both of our cases, identification of some epithelial ultrastructural and immunohistochemical features in cells of otherwise sarcomatous phenotype lends support to the common epithelial origin of these neoplasms. Moreover, positive staining for MDM2 and CDK4 in our cases with equally strong reactions in both carcinomatous and sarcomatous elements provides evidence of a role for these molecules in the pathogenesis of carcinosarcoma. In contrast, in cases of squamous cell carcinoma with prominent stromal reaction only the epithelial cells stained strongly for MDM2 and CDK4. These differences in the MDM2 and CDK4 immunohistochemical profile between carcinosarcomas and carcinomas of the esophagus may assist in their differential diagnosis.     

High frequency of homozygous deletions of CDK4I gene in childhood acute lymphoblastic leukaemia

Summary. To determine the incidence of homozygous deletions of the newly identified tumour suppressor gene, CDK4I, molecular genomic DNA analyses by PCR technique were performed on primary neoplastic cells from 22 childhood acute leukaemias obtained at presentation. The blast cells derived in all the analysed cases from bone marrow. We found that none of acute myeloblastic leukaemias (four cases) showed the CDK4I alteration, whereas 6/13 (46%) common acute lymphoblastic leukaemias (ALLs) displayed homozygous deletions. Moreover, and even more important, all the blasts purified from ALLs derived from early lymphoid precursors (three early-T ALLs and two pre-B ALLs) showed the absence of CDK4I gene. When the entire coding sequence of the CDK4I gene from samples without homozygous deletions was analysed by the single-strand conformational polymorphism method, no point mutations were identified. These results demonstrate that CDK4I gene deletions are very frequent and probably early events in childhood acute leukaemias of lymphoid origin and especially in early-T and pre-B ALLs. Moreover, the molecular mechanism of the loss of function of the gene is correlated, at least in childhood ALLs, almost exclusively to deletions and not to point mutations.     

CDK6及E2F-1参与细胞周期调控pRb通路的研究进展

目前肿瘤的本质被认为是一种细胞周期病,细胞周期的调控是一种受多条件限制、由多因素参与的复杂并且精细的过程,其经典途径包括pRb途径及p53途径,其中任何一个环节出现异常,均可能导致肿瘤的发生。细胞周蛋白依赖性激酶6(CDK6)、核转录调节因子E2F-1均参与细胞周期调控的RB通路,在G1期向S期转换过程中起到非常关键的作用。现有研究已证实,在人体的很多肿瘤中CDK6、E2F-1表达均呈现异常,其与肿瘤的发生发展有密切联系。因此,进一步了解二者在细胞周期调控中的作用及其在不同类别肿瘤中的表达异常对了解肿瘤的发生发展有重大意义。