鼻咽癌组织中BLU与cyclin D1和cyclin B1的表达及其临床意义

目的 探究BLU与cyclin D1和cyclin B1在鼻咽癌（NPC）组织中的表达及其临床意义。方法 采用免疫组化法检测97例NPC组织及36例慢性鼻咽炎（CN）组织中BLU与cyclin D1、cyclin B1的表达,运用统计学方法分析三者的表达与NPC患者临床病理特征参数及预后的关系。结果 在NPC组织中,BLU阳性表达率低于CN中的阳性表达率,cyclin D1与cyclin B1阳性表达率高于CN组织的阳性表达率（P<0.05）。BLU表达与年龄、T分期有相关性,cyclin D1表达与临床分期、淋巴结转移有相关性,cyclin B1表达与临床分期与T分期有相关性（P<0.05）。Spearman等级相关分析结果显示BLU与cyclin D1在NPC组织中表达呈负相关（r=-0.378,P=0.011）,BLU与cyclin B1在NPC组织中表达无明显相关性（r=0.096,P=0.089）,cyclin D1与cyclin B1在NPC组织中表达无相关性（r=0.084,P=0.191）。BLU表达阳性组的总生存率高于表达阴性组,cyclin D1表达阳性组总生存率低于表达阴性组（P<0.05）,cyclin B1表达阳性组与表达阴性组总生存率差异无统计学意义（P>0.05）。Log-rank法分析结果显示BLU、cyclin D1、T分期、N分期与患者的预后有关（P<0.05）;Cox回归模型分析显示BLU、cyclin D1及淋巴结转移是NPC预后的独立预测因子。结论 BLU表达下调,而cyclin B1和cyclin D1高表达,可能在NPC发生发展中产生重要作用,其有可能成为其中评估NPC预后的标志物。     

BLU基因在鼻T/NK细胞淋巴瘤石蜡与冻存组织中的甲基化状态比较研究

目的 :探讨 BL U基因在 T/ NK细胞淋巴瘤发生中的作用与分子病理诊断中的应用价值。方法 :选用已经确诊为鼻 T/ NK细胞淋巴瘤 1 2例的冻存组织标本与 2 0例石蜡组织标本 ,从组织中提取 DNA,用 MSP方法检测 BL U基因启动子的甲基化状态。结果 :在 1 2个冰冻组织病例中 ,用 M引物扩增的产物 ,BLU基因全部为阳性 ,U引物扩增的产物 ,BL U基因 1 1例为阳性 ;2 0例石蜡组织病例中 ,M引物扩增的产物 6例阳性 ,U引物扩增的产物 1 2例阳性。表明 BLU基因在鼻 T/ NK细胞淋巴瘤中有高度甲基化 ,冰冻组织中的甲基化检出率明显高于石蜡组织。结论 :BL U基因启动子 Cp G岛在鼻 T/ NK细胞淋巴瘤中普遍高度甲基化 ,表明此抑癌基因被失活 ,可能是 T/ NK细胞淋巴瘤的发病机制之一。     

Rottlerin inhibits multiple steps involved in insulin-induced glucose uptake in 3T3-L1 adipocytes

Recently, it was shown that rottlerin inhibits insulin-stimulated glucose uptake and reduces intracellular adenosine triphosphate (ATP) levels in 3T3-L1 adipocytes, suggesting that these two events are causally linked. However, several other reports show that ATP-depletion induces glucose uptake in both muscle cells and adipocytes. In the present study, the mechanism of inhibition by rottlerin was studied in detail, in order to resolve this apparent discrepancy. It was found that rottlerin strongly reduces insulin-stimulated 2-deoxyglucose (2-DOG) uptake in 3T3-L1 adipocytes by a partial inhibition of the translocation of the insulin-responsive GLUT4 glucose transporter towards the plasma membrane (PM). Whereas the insulin-induced phosphatidyl-inositol-3' (PI-3') kinase signaling pathway is unaffected by rottlerin, Cbl tyrosine phosphorylation, which provides an essential, PI-3' kinase-independent signal towards GLUT4 translocation, is markedly attenuated. Furthermore, we also observed a direct inhibitory effect of rottlerin on insulin-induced glucose uptake in 3T3-L1 adipocytes. The direct inhibition of insulin-stimulated 2-DOG uptake by rottlerin displayed characteristics of uncompetitive inhibition: with the K(m(app)) of glucose uptake reduced from 1.6 to 0.9 mM and the V(max(app)) reduced from 5.2 to 1.0 nmol/minmg in the presence of rottlerin. In conclusion, rottlerin inhibits multiple steps involved in insulin-stimulated 2-DOG uptake in 3T3-L1 adipocytes. The observed reduction in GLUT4 translocation towards the PM and the uncompetitive inhibition of the glucose transport process provide alternative explanations for the inhibitory effects of rottlerin aside from the effects of rottlerin on intracellular levels of ATP.     

胃癌BLU基因启动子区高甲基化的临床意义

目的研究BLU基因启动子区高甲基化在胃癌发生发展中的作用。方法应用甲基化特异性PCR技术分别检测92例胃癌组织与相应的癌旁组织以及79例胃癌患者与79例正常人外周血BLU基因甲基化水平,分析BLU基因甲基化与临床病理参数的相关性。结果胃癌组织BLU基因甲基化率高于癌旁组织(67.39%vs.52.17%)(P<0.05)。BLU基因甲基化与患者性别、年龄、肿瘤大小、分化程度、TNM分期和浸润深度之间无明显相关性(P>0.05),但与肿瘤淋巴结转移密切相关(P<0.05)。胃癌患者外周血BLU基因甲基化率与正常人外周血比较差异无统计学意义(63.29%vs.56.96%)(P>0.05)。结论 BLU基因启动子的CpG岛在胃癌组织存在高甲基化现象,提示BLU基因的高甲基化可能与抑癌基因被失活从而导致胃癌的发生有关。BLU甲基化可能参与胃癌淋巴结转移。     

Human inter-individual variability in metabolism and genotoxic response to zidovudine

A mainstay of the antiretroviral drugs used for therapy of HIV-1, zidovudine (AZT) is genotoxic and becomes incorporated into DNA. Here we explored host inter-individual variability in AZT-DNA incorporation, by AZT radioimmunoassay (RIA), using 19 different strains of normal human mammary epithelial cells (NHMECs) exposed for 24 h to 200 microM AZT. Twelve of the 19 NHMEC strains showed detectable AZT-DNA incorporation levels (16 to 259 molecules of AZT/10(6) nucleotides), while 7 NHMEC strains did not show detectable AZT-DNA incorporation. In order to explore the basis for this variability, we compared the 2 NHMEC strains that showed the highest levels of AZT-DNA incorporation (H1 and H2) with 2 strains showing no detectable AZT-DNA incorporation (L1 and L2). All 4 strains had similar (> or =80%) cell survival, low levels of accumulation of cells in S-phase, and no relevant differences in response to the direct-acting mutagen bleomycin (BLM). Finally, when levels of thymidine kinase 1 (TK1), the first enzyme in the pathway for incorporation of AZT into DNA, were determined by Western blot analysis in all 19 NHMEC strains at 24 h of AZT exposure, higher TK1 protein levels were found in the 12 strains showing AZT-DNA incorporation, compared to the 7 showing no incorporation (p=0.0005, Mann-Whitney test). Furthermore, strains L1 and L2, which did not show AZT-DNA incorporation at 24 h, did have measurable incorporation by 48 and 72 h. These data suggest that variability in AZT-DNA incorporation may be modulated by inter-individual differences in the rate of induction of TK1 in response to AZT exposure.     

Hypermethylation of RASSF1A and BLU tumor suppressor genes in non-small cell lung cancer: implications for tobacco smoking during adolescence

The putative tumor suppressors RASSF1A and BLU are mapped adjacent to one another on chromosome 3p21.3, a region frequently deleted in lung cancer. These genes are often inactivated by promoter hypermethylation, but the association of this inactivation with clinical features of the disease or with carcinogen exposure has been poorly studied. Early age starting smoking has been hypothesized as an independent risk factor for lung cancer, and mechanistically, adolescence may constitute a critical period for tobacco carcinogen exposure. To study the relationship of tobacco smoke exposure with hypermethylation of RASSF1A and BLU, methylation-specific PCR was performed on a case series study of incident, surgically resected non-small cell lung cancer (NSCLC), and the prevalence of this alteration was examined in relation to clinical and exposure information collected on the patients. Hypermethylation of the RASSF1A promoter occurred in 47% (83/178) and of the BLU promoter in 43% (68/160) of NSCLC tumors examined. There was no significant association between methylation of these 2 genes, but methylation of either of these genes tended to occur more often in the adenocarcinoma (AC) histology compared to squamous cell carcinoma (SCC). Controlling for pack-years smoked, age, gender and histology, starting smoking under age 18 was significantly related to RASSF1A methylation [prevalence ratio (PR) = 1.6, 95% confidence interval [CI] = 1.1-2.3]. These results indicate that starting smoking under age 18 is an independent risk for RASSF1A hypermethylation, thus identifying a molecular alteration related to the epidemiologic effect of teenage smoking as a lung cancer risk.     

Functional studies of the chromosome 3p21.3 candidate tumor suppressor gene BLU/ZMYND10 in nasopharyngeal carcinoma

Chromosome 3p plays an important role in tumorigenesis in many cancers, including nasopharyngeal carcinoma (NPC). We have previously shown chromosome 3p can suppress tumor growth in vivo by using the monochromosome transfer approach, which indicated the chromosome 3p21.3 region was critical for tumor suppression. BLU/ZMYND10 is one of the candidate tumor suppressor genes mapping in the 3p21.3 critical region and is a candidate TSG for NPC. By quantitative RT-PCR, it is frequently downregulated in NPC cell lines (83%) and NPC biopsies (80%). However, no functional studies have yet verified the functional role of BLU/ZMYND10 as a tumor suppressor gene. In the current study, a gene inactivation test (GIT) utilizing a tetracycline regulation system was used to study the functional role of BLU/ZMYND10. When BLU/ZMYND10 is expressed in the absence of doxycycline, the stable transfectants were able to induce tumor suppression in nude mice. In contrast, downregulation of BLU/ZMYND10 in these tumor suppressive clones by doxycycline treatment restored the tumor formation ability. This study provides the first significant evidence to demonstrate BLU/ZMYND10 can functionally suppress tumor formation in vivo and is, therefore, likely to be one of the candidate tumor suppressor genes involved in NPC.     

TSLC1和BLU基因在鼻NK／T细胞淋巴瘤中CpG岛甲基化研究

 目的 了解鼻NK／T细胞淋巴瘤中抑癌基因TSLC1和BLU的甲基化状况，并探讨其在鼻NK／T细胞淋巴瘤发生发展中的作用及与临床病理参数之间的关系。方法 应用甲基化特异性PCR（MSP）技术，检测30例鼻NK／T细胞淋巴瘤、10例鼻咽淋巴组织增生中TSLC1和BLU基因启动子区的甲基化状况；应用原位杂交方法对30例鼻NK／T细胞淋巴瘤进行EB病毒检测。结果 30例鼻NK／T细胞淋巴瘤中, TSLC1和BLU基因的甲基化频率分别为83.3 %（25／30）和50 %（15／30），且TSLC1和BLU基因中至少有1个抑癌基因发生甲基化的频率为86.7 %（26／30）；10例鼻咽淋巴组织增生中，2例发生了TSLC1基因甲基化，而BLU 基因全部甲基化阴性而非甲基化阳性。未发现TSLC1和BLU基因CpG 岛甲基化与EB病毒感染有关。TSLC1和BLU基因启动子区CpG岛甲基化与临床病理特征之间均无统计学相关性（P＞0.05）。结论 30例鼻NK／T细胞淋巴瘤中多基因的启动子甲基化是一种普遍的事件。两种抑癌基因启动子区CpG 岛均具有很高的甲基化频率，表明其在鼻NK／T细胞淋巴瘤的发生发展中具有重要作用，可能对肿瘤的早期诊断及预后评估具有重要意义。