黄连NRAMP3基因的克隆与生物信息学分析＊

目的 克隆黄连（Coptis chinensis Franch.）中自然抗性相关巨噬细胞蛋白（Natural Resistance-Associated Macrophage Protein，NRAMP）的编码基因，并进行生物信息学分析。方法 从黄连基因组中比对NRAMP3基因，并根据比对的基因序列设计特异性引物，经PCR扩增得到的黄连NRAMP3编码序列，进行克隆、测序和生物信息学分析，并利用qPCR技术对黄连NRAMP3基因进行时空表达分析。结果 得到黄连NRAMP3基因cDNA序列，全长1617 bp，编码538个氨基酸，通过与GenBank上的其他蛋白序列比对，将其命名为CcNRAMP3；序列分析显示，黄连NRAMP3基因编码的氨基酸序列包含一个典型的NRAMP结构域（PF01566），有12个跨膜结构域，亚细胞定位于液泡膜上，具有疏水性强的特点。二级结构中肽链构象主要包括α-螺旋与无规则卷曲两部分；三级结构模型具有葡萄球菌锰转运突变体（MntH）的晶体结构。利用系统进化关系分析推测它可能具有转运重金属元素Cd功能。对黄连NRAMP3基因的组织表达分析表明，CcNRAMP3基因在黄连叶片中表达量最高。在遭受镉胁迫时，在须根中表达量先升高后降低，该基因很可能主要在根部对镉进行响应并发挥作用。结论 本研究首次通过克隆得到黄连NRAMP3基因，并运用生物信息学方法对其理化性质、结构特征等进行了分析预测，这些结果将为黄连NRAMP3基因的功能研究以及其对镉转运的调控机制提供理论依据和基因资源。     

骨肉瘤差异表达基因的生物信息学分析及关键基因筛选

目的筛选成骨型骨肉瘤与正常成骨细胞的差异表达基因, 寻找成骨型骨肉瘤发生、发展的关键基因。方法从Gene Expression Omnibus(GEO)数据库获得正常成骨细胞和骨肉瘤组织的基因表达数据集GSE33382, 采用R语言的limma包筛选正常成骨细胞和成骨型骨肉瘤的差异表达基因, 对差异表达基因进行京都基因与基因组百科全书(KEGG)通路富集分析。采用String数据库构建蛋白交互网络, 应用Cytoscape软件的分子复合物检测(MCODE)插件筛选互作网络中的网络模块, 应用Cytoscape软件中的BiNGO模块对MCODE筛选得到的前3个主要模块所包含的差异表达基因进行基因本体(GO)富集分析。采用MCC算法筛选蛋白互作网络中前10个关键基因。从GEO数据库获得骨肉瘤的基因表达和生存数据集GSE39055, 采用Kaplan-Meier法进行生存分析。选取2005年1月至2015年12月福建医科大学附属第一医院收治的48例成骨型骨肉瘤患者的资料进行验证, 采用免疫组化法测定骨肉瘤组织中STC2蛋白的表达, 结合患者的临床资料进行生存分析。结果从GSE33382数据集...     

基于生物信息学筛选早发性乳腺癌差异表达基因

目的筛选并分析与早发性乳腺癌发生、发展相关的靶基因。 方法(1)在美国国立生物技术信息中心的公共基因芯片数据库(GEO)中检索早发性乳腺癌样本及非早发性乳腺癌样本相关基因芯片数据。对上述数据使用GEO2R、R4.1.2及Venn软件筛选出相关差异表达基因(DEGs)，并运用在线分析工具(Web Gestalt)对DEGs，进行相关功能和信号通路富集分析。(2)同时，通过String在线数据库构建DEGs编码的蛋白质-蛋白质相互作用(PPI)网络，并利用Cytohubba插件对该网络中的基因进行评分，筛选出枢纽基因。将枢纽基因导入Kaplan-Meier生存分析工具(Kaplan-Meier Plotter)，评估枢纽基因在早发性乳腺癌的预后价值。(3)将肿瘤基因组图谱(TCGA)数据库中的肿瘤组织以年龄为标准进行分组，分析枢纽基因在各年龄组中的表达，并与正常组织中的表达进行比较，对得到的枢纽基因进行验证。DEGs表达量的多组间比较使用Kruskal-Wallis H检验，使用Bonferroni法进行两两比较。 结果(1)筛选出编号为GSE89116、GSE109169、GSE36295的基因芯片数据集，共得到80个差异表达基因，其中上调差异表达基因17个，下调差异表达基因63个。富集分析显示：DEGs主要富集在脂质代谢和氧化还原过程以及PPAR信号通路、AMPK信号通路上。(2)在PPI中发现主要的关键基因为PPARG、ADIPOQ、LIPE、PCK1、PDK4、ACACB、PLIN1、CAV1、CD36、ANGPTL4。ACACB、ADIPOQ、CAV1、LIPE、PLIN1、PPARG基因的低表达与乳腺癌患者的不良OS相关(HR＝0.69、0.84、0.76、0.88、0.78、0.82；95%CI：0.59~0.80、0.76~0.93、0.67~0.83、0.79~0.97、0.70~0.86、0.73~0.90；P均<0.050)。(3)ACACB、ADIPOQ、LIPE、PLIN1、CAV1及PPARG这6个与预后相关的基因在正常组织中的表达量均远高于各年龄组肿瘤组织中的表达量(χ²＝104.03、179.57、161.85、189.87、118.56、103.62，P均<0.001)，早发性乳腺癌组(21~40岁)的LIPE、PLIN1表达量低于41~60岁、61~80岁年龄组，差异具有统计学意义(LIPE: Z＝21.07、23.12, P均<0.050; PLIN1：Z＝16.89、18.76, P均<0.050)。 结论早发性乳腺癌与非早发性乳腺癌存在差异基因表达谱，LIPE、PLIN1可能是早发性乳腺癌发生、发展的关键基因。     

In silico repurposing the Rac1 inhibitor NSC23766 for treating PTTG1-high expressing clear cell renal carcinoma

The pituitary tumor-transforming gene 1 (PTTG1), also known as Securin, is considered an oncogene. This study aimed to investigate the role of PTTG1 in clear cell renal cell carcinoma (ccRCC) using in silico bioinformatics approaches. A pan-cancer analysis using The Cancer Genome Atlas (TCGA) data indicated that among all cancer types copy number amplification of PTTG1 gene was most frequently found in ccRCC. However, amplification of PTTG1 gene copy number did not correlate with the increase of mRNA level in ccRCC, and did not predict the patients' overall survival. Instead, ccRCC was correlated with overexpression of PTTG1 mRNA, and its expression level was stage-dependent increased in cancer patients. An outlier analysis using the Oncomine database suggested that PTTG1 mRNA expression served as a good biomarker for ccRCC. Pathway analysis for upregulated genes enriched in PTTG1-high expressing ccRCC patients found that PTTG1 overexpression was associated with mitotic defects. Mining drug sensitivity data using the Cancer Therapeutics Response Portal (CTRP) discovered that PTTG1-high expressing ccRCC cell lines were susceptible to a Rac1 (Ras-related C3 botulinum toxin substrate 1) inhibitor NSC23766. Therefore, this study provides an in silico insight into the role of PTTG1 in ccRCC, and repurposes the Rac1 inhibitor NSC23766 for treating PTTG1-high expressing ccRCC.     

生物信息学分析IGF-2R在乳腺癌中的作用机制

目的 确定IGF-2R基因对乳腺癌的调控作用,挖掘参与乳腺癌发生发展潜在的基因及通路。方法 利用“GEOquery”、“idmap2.0”、“limma”、“Clusterprolifer”等R包筛选乳腺肿瘤组织与正常组织的差异表达基因,并进行GO和KEGG分析。STRING、GEPIA和UALACN数据库绘制蛋白互作网络,分析IGF-2R基因与乳腺癌Hub基因的相关性,以及IGF2R表达水平与乳腺癌患者基本情况的相关性。结果 筛选得到128个上调差异表达基因,256个下调差异表达基因；IGF-2R基因与核心基因ASPM、RRM2相关性显著；IGF-2R基因表达水平在乳腺癌组织中显著降低(P<0.05)；IGF-2R表达水平与患者年龄(20-80岁)、临床分期(Ⅰ、Ⅱ、Ⅲ)、绝经情况和淋巴结转移密切相关(P<0.05)。IGF-2R基因的表达水平仅在Luminal型(LuminalA型、Luminal B-HER2阴性型)乳腺癌中显著降低(P<0.05)。结论IGF-2R通过与ASPM和RRM2正相关参与乳腺癌的调控作用,有望为乳腺癌的防治提供新的思路。     

小细胞肺癌关键基因及信号通路分析

目的 探究SCLC基因调控机制，为寻找SCLC早期诊断及靶向治疗潜在的生物标志物提供依据。方法 采用生物信息学方法从公共基因芯片数据库获取小细胞肺癌（SCLC）mRNA数据并筛选出差异表达基因（DEGs），对DEGs进行基因本体（GO）和基因组百科全书数据库（KEGG）富集分析，构建蛋白互作网络，筛选出核心基因并利用Kaplan-Meier在线工具进行生存分析。结果 17例SCLC组织样本和19例正常肺组织样本中筛选出248个DEGs，包括172个高表达基因和76个低表达基因（P<0.05）。GO和KEGG富集分析结果显示，DEGs的功能主要涉及细胞周期、DNA复制、错配修复、P53信号通路等，蛋白互作分析网络筛选出6个节点度最高的核心基因：TOP2A、PCNA、RFC4、 FEN1、CCNA2和MCM2，并与患者预后相关。结论 DEGs涉及的分子功能和信号通路可能是SCLC发生的分子机制，而核心基因可能是治疗SCLC的潜在靶点。     

Microarray-based measurement of microRNA-449c-5p levels in hepatocellular carcinoma and bioinformatic analysis of potential signaling pathways

The clinical role and potential molecular mechanisms of microRNA-449c-5p (miR-449c-5p) in hepatocellular carcinoma (HCC) tissues remains unclear. Combining multiple bioinformatic tools, we studied the miR-449c-5p expression levels in HCC tissues and explored possible target genes and related signaling pathways. First, miR-449c-5p expression data from microarrays provided by publicly available sources were mined and analyzed using various meta-analysis methods. Next, genes that were downregulated after miR-449c-5p mimic transfection into HCC cells were identified, and in silico methods were used to predict potential target genes. Several bioinformatic assessments were also performed to evaluate the possible signaling pathways of miR-449c-5p in HCC. Five microarrays were included in the current study, including GSE98269, GSE64632, GSE74618, GSE40744 and GSE57555. The standard mean difference was 0.44 (0.07–0.80), and the area under the curve was 0.68 (0.63–0.72), as assessed by meta-analyses, which consistently indicated the upregulation of miR-449c-5p in HCC tissues. A total of 2244 genes were downregulated after miR-449c-5p mimic transfection into an HCC cell line, while 5217 target genes were predicted by in silico methods. The overlap of these two gene pools led to a final group of 428 potential target genes of miR-449c-5p. These 428 potential target genes were primarily enriched in the homologous recombination pathway, which includes DNA Polymerase Delta 3 (POLD3). Data mining with Oncomine and the Human Protein Atlas showed a decreasing trend in POLD3 mRNA and protein levels in HCC tissue samples. This evidence suggests that miR-449c-5p could play an essential role in HCC through various pathways and that POLD3 could be a potential miR-449c-5p target. However, these in silico findings should be validated with further experiments.     

生物信息学在肝细胞癌风险预测中的应用

生物信息学是一门交叉科学,通过综合运用数学、计算机科学和生物学的各种工具,来阐明和理解大量生物数据所包含的生物学意义。随着基因组学测序技术的不断发展,产生大量的生物学数据资源,从大数据中挖掘所蕴藏的生物学意义,已成为了当前亟待解决的主要任务之一。本文主要归纳总结基于特征基因的肝癌风险预测模型,为肝癌的早期检测、预后和治疗方案的优化提供新观点。     

Proteomic analysis of Brucella melitensis and Brucella ovis for identification of virulence factor using bioinformatics approachs

The genus Brucella includes several genetically monomorphic species but with different phenotypic and virulence characteristics. In this study, proteins of two Brucella species, B. melitensis type strain 16 M and B. ovis REO198 were compared by proteomics approach, in order to explain the phenotypic and pathophysiological differences among Brucella species and correlate them with virulence factors.Protein extracts from the two Brucella species were separated by SDS-PAGE and 5 areas, which resulted qualitatively and quantitatively different, were analyzed by nLC-MS/MS.A total of 880 proteins (274 proteins of B. melitensis and 606 proteins of B. ovis) were identified; their functional and structural features were analyzed by bioinformatics tools. Four unique peptides belonging to 3 proteins for B. ovis and 10 peptides derived from 7 proteins for B. melitensis were chosen for the high amount of predicted B-cell epitopes exposed to the solvent. Among these proteins, outer-membrane immunogenic protein (N8LTS7) and 25 kDa outer-membrane immunogenic protein (Q45321), respectively of B. ovis and B. melitensis, could be interesting candidates for improving diagnostics tests and vaccines.Moreover, 8 and 13 outer and periplasmic non homologue proteins of B. ovis and B. melitensis were identified to screen the phenotypic differences between the two Brucella strains. These proteins will be used to unravel pathogenesis and ameliorate current diagnostic assays.