Genomic sequencing and comparative analysis of Epstein-Barr virus genome isolated from primary nasopharyngeal carcinoma biopsy

Whether certain Epstein-Barr virus (EBV) strains are associated with pathogenesis of nasopharyngeal carcinoma (NPC) is still an unresolved question. In the present study, EBV genome contained in a primary NPC tumor biopsy was amplified by Polymerase Chain Reaction (PCR), and sequenced using next-generation (Illumina) and conventional dideoxy-DNA sequencing. The EBV genome, designated HKNPC1 (Genbank accession number JQ009376) is a type 1 EBV of approximately 171.5 kb. The virus appears to be a uniform strain in line with accepted monoclonal nature of EBV in NPC but is heterogeneous at 172 nucleotide positions. Phylogenetic analysis with the four published EBV strains, B95-8, AG876, GD1, and GD2, indicated HKNPC1 was more closely related to the Chinese NPC patient-derived strains, GD1 and GD2. HKNPC1 contains 1,589 single nucleotide variations (SNVs) and 132 insertions or deletions (indels) in comparison to the reference EBV sequence (accession number NC007605). When compared to AG876, a strain derived from Ghanaian Burkitt's lymphoma, we found 322 SNVs, of which 76 were non-synonymous SNVs and were shared amongst the Chinese GD1, GD2 and HKNPC1 isolates. We observed 88 non-synonymous SNVs shared only by HKNPC1 and GD2, the only other NPC tumor-derived strain reported thus far. Non-synonymous SNVs were mainly found in the latent, tegument and glycoprotein genes. The same point mutations were found in glycoprotein (BLLF1 and BALF4) genes of GD1, GD2 and HKNPC1 strains and might affect cell type specific binding. Variations in LMP1 and EBNA3B epitopes and mutations in Cp (11404 C>T) and Qp (50134 G>C) found in GD1, GD2 and HKNPC1 could potentially affect CD8(+) T cell recognition and latent gene expression pattern in NPC, respectively. In conclusion, we showed that whole genome sequencing of EBV in NPC may facilitate discovery of previously unknown variations of pathogenic significance.     

Expression of the c-Met Proto-Oncogene and Integrin α5β1 in Human Gastric Cardia Adenocarcinoma

The hepatocyte growth factor receptor c-Met, a receptor tyrosine kinase, and Integrin α5β1, one of the main ECM receptors of hepatocytes have been reported to play important roles in tumor growth by activating mitogenic signaling pathways. In human gastric cardia adenocarcinoma, however, expression of the c-Met and Integrin α5β1 have not been reported. Here we examined the mRNA levels and protein expressions of these two genes and their relationship in human normal gastric cardia mucosa and primary carcinomas. Quantitative real-time PCR was used to analyze the mRNA expression of both c-Met and Integrin α5β1. The relationship between c-Met and Integrin α5β1 expression and the histologic characteristics of tumors were studied. Western blot analysis was performed to investigate the presence of c-Met and Integrin α5β1. The expression patterns of c-Met and Integrin α5β1 in 45 frozen slides of cardia adenocarcinoma were identified by immunohistochemistry. Our results indicate that the expression of c-Met and of Integrin α5β1 was significantly associated with tumor differentiation, TNM, and metastasis via the lymphogenic route. A significant positive correlation was also found between c-Met and Integrin α5β1 mRNA expression, suggesting that expression of c-Met and Integrin α5β1 has mechanical significance in the early stages of human gastric cardia adenocarcinoma.     

利用异源生物生产青蒿素及其前体的研究进展

青蒿素是从中药青蒿中分离出来的一种倍半萜内酯类化合物,也是目前最有效的抗疟疾药物,对人类健康意义重大。该文通过对青蒿素生物合成途径及其相关酶的介绍,综述了利用异源生物通过组合生物合成途径生产青蒿素及其前体的最新研究进展。     

黄果厚壳桂种内与种间竞争的数量关系

采用Hegyi单木竞争指数模型对鼎湖山季风常绿阔叶林建群种黄果厚壳桂的种内、种间竞争强度进行定量分析.结果表明,黄果厚壳桂所受到的竞争强度随着林木径级的增大而逐渐减小.黄果厚壳桂种内竞争较与伴生树种云南银柴的种间竞争弱.黄果厚壳桂种内和种间竞争强度的顺序为:云南银柴>黄果厚壳桂种内>荷木>白颜树>肖蒲桃>锥栗>红车>臀形果>柏拉木>水石梓>窄叶半枫荷>厚壳桂.整个林分及黄果厚壳桂种内竞争木对对象木的竞争强度与对象木的胸径大小之间的关系近似服从幂函数关系,而伴生树种竞争木对对象木的竞争强度与对象木的胸径大小之间的关系近似服从对数函数关系.竞争强度和对象木的胸径大小呈显著负相关关系.     

Hepatitis B virus X protein activates the p38 mitogen-activated protein kinase pathway in dedifferentiated hepatocytes

Hepatitis B virus X protein (pX) is implicated in hepatocarcinogenesis by an unknown mechanism. Employing a cellular model linked to pX-mediated transformation, we investigated the role of the previously reported Stat3 activation by pX in hepatocyte transformation. Our model is composed of a differentiated hepatocyte (AML12) 3pX-1 cell line that undergoes pX-dependent transformation and a dedifferentiated hepatocyte (AML12) 4pX-1 cell line that does not exhibit transformation by pX. We report that pX-dependent Stat3 activation occurs only in non-pX-transforming 4pX-1 cells and conclude that Stat3 activation is not linked to pX-mediated transformation. Maximum Stat3 transactivation requires Ser727 phosphorylation, mediated by mitogenic pathway activation. Employing dominant negative mutants and inhibitors of mitogenic pathways, we demonstrate that maximum, pX-dependent Stat3 transactivation is inhibited by the p38 mitogen-activated protein kinase (MAPK)-specific inhibitor SB 203580. Using transient-transreporter and in vitro kinase assays, we demonstrate for the first time that pX activates the p38 MAPK pathway only in 4pX-1 cells. pX-mediated Stat3 and p38 MAPK activation is Ca(2+) and c-Src dependent, in agreement with the established cellular action of pX. Importantly, pX-dependent activation of p38 MAPK inactivates Cdc25C by phosphorylation of Ser216, thus initiating activation of the G(2)/M checkpoint, resulting in 4pX-1 cell growth retardation. Interestingly, pX expression in the less differentiated hepatocyte 4pX-1 cells activates signaling pathways known to be active in regenerating hepatocytes. These results suggest that pX expression in the infected liver effects distinct mitogenic pathway activation in less differentiated versus differentiated hepatocytes.     

利用SRAP和SSR分子标记检测分析29份棉花种质遗传完整性

利用SRAP和SSR分子标记检测29份棉花种质遗传完整性。结果表明,无论每一份不同更新发芽率水平繁殖后代的种质之间,还是每一份不同繁殖世代数种质之间,其等位基因频率差异不显著,也没有检测到稀有等位基因缺失的情况。本试验表明不同更新发芽率水平和繁殖世代数差异没有对棉花这种常异花授粉作物种质遗传完整性变化产生影响。     

Decitabine Rescues Cisplatin Resistance in Head and Neck Squamous Cell Carcinoma

Cisplatin resistance in head and neck squamous cell carcinoma (HNSCC) reduces survival. In this study we hypothesized that methylation of key genes mediates cisplatin resistance. We determined whether a demethylating drug, decitabine, could augment the anti-proliferative and apoptotic effects of cisplatin on SCC-25/CP, a cisplatin-resistant tongue SCC cell line. We showed that decitabine treatment restored cisplatin sensitivity in SCC-25/CP and significantly reduced the cisplatin dose required to induce apoptosis. We then created a xenograft model with SCC-25/CP and determined that decitabine and cisplatin combination treatment resulted in significantly reduced tumor growth and mechanical allodynia compared to control. To establish a gene classifier we quantified methylation in cancer tissue of cisplatin-sensitive and cisplatin-resistant HNSCC patients. Cisplatin-sensitive and cisplatin-resistant patient tumors had distinct methylation profiles. When we quantified methylation and expression of genes in the classifier in HNSCC cells in vitro, we showed that decitabine treatment of cisplatin-resistant HNSCC cells reversed methylation and gene expression toward a cisplatin-sensitive profile. The study provides direct evidence that decitabine restores cisplatin sensitivity in in vitro and in vivo models of HNSCC. Combination treatment of cisplatin and decitabine significantly reduces HNSCC growth and HNSCC pain. Furthermore, gene methylation could be used as a biomarker of cisplatin-resistance.     

中国特有种四合木种群遗传多样性的RAPD分析

采用随机扩增多态性 DNA(RAPD)技术检测了西鄂尔多斯高原特有种四合木种群 5个斑块的遗传多样性。2 2个扩增引物产生 1 1 6条带 ,Shannon信息指数和 Nei指数对 RAPD数据的分析表明 :四合木种群存在较高的遗传多样性 ,其中千里山斑块的遗传多样性和多态位点比例较高 ,石嘴山斑块的最低。遗传多样性的 86.5 %存在于斑块内 ,斑块间的遗传变异为 1 3 .5 %。遗传距离与地理距离无直接相关关系。这些结果说明 ,遗传多样性反映了四合木种群基因组 DNA存在较高的变异性 ;同时各斑块间存在一定的基因流 ,四合木各斑块可看成是处于同一种群的半隔离状态 (meta-种群 ) ,对四合木应注意保护遗传多样性丰富的 meta-种群。     

Prediction of Poor Prognosis in Breast Cancer Patients Based on MicroRNA-21 Expression: A Meta-Analysis

BackgroundMicroRNA-21 (miRNA-21 or miR-21) may act as a prognostic biomarker of cancer. However, the available evidence is controversial. Therefore, the present meta-analysis summarizes this evidence and evaluates the prognostic role of this gene in breast cancer.MethodsThe meta-analysis was conducted by searching the databases of PubMed, EMBASE, Web of Science and Chinese database-China National Knowledge Infrastructure (CNKI). Data were extracted from studies that investigated the association between miR-21 expression and survival outcomes in breast cancer patients. With respect to survival outcomes, the pooled hazard ratios (HRs) of miR-21 were calculated given a 95% confidence interval (CI).ResultsOur meta-analysis identified a total of 10 studies involving 1,439 cases. Further investigation demonstrated that a high miR-21 expression can predict poor overall survival (OS) (HR = 2.57, 95% CI: 1.37—4.81, P = 0.003) and shortened disease-free/recurrence-free survival (DFS/RFS) (HR = 1.45, 95% CI: 1.16—1.82, P = 0.001) in breast cancer patients. Moreover, high miR-21 expression was significantly correlated with lowered OS in the Asian group (HR = 5.07, 95% CI: 2.89—8.92, P < 0.001), but not in the Caucasian cohort (HR = 1.44, 95% CI: 0.99—2.10, P = 0.058). Furthermore, odds ratios (ORs) showed that up-regulated miR-21 levels were associated with multiple clinical characteristics.ConclusionOur results indicated that miR-21 can predict unfavorable prognoses in breast cancer patients, especially in Asians.