一种制备抗复合抗原单克隆抗体的方法

目的 建立通过单次细胞融合制备抗复合抗原(多种抗原)单克隆抗体的方法。方法 用复合抗原(甲胎蛋白、癌胚抗原、乙型肝炎表面抗原、乙型肝炎核心抗原、乙型肝炎e抗原)免疫BALB/c小鼠,采用常规杂交瘤技术制备单克隆抗体。通过Protein-G亲和层析纯化阳性杂交瘤细胞株腹水,并通过亚类试剂盒法和非竞争ELISA法分别测定抗体亚类和亲和常数,同时应用免疫印迹分析其特异性。结果 通过单次细胞融合共获得20株抗上述复合抗原的单克隆抗体,其中针对甲胎蛋白的单克隆抗体5株、针对癌胚抗原的单克隆抗体6株、针对乙型肝炎表面抗原的单克隆抗体3株;针对乙型肝炎核心抗原的单克隆抗体4株、针对乙型肝炎e抗原的单克隆抗体3株。已鉴定的部分阳性杂交瘤细胞株亚类均为IgG1,抗体亲和常数介于1×10⁹M^-1~2.8×10¹¹M^-1,免疫印迹分析显示,所获得的单抗都与其抗原发生特异性结合。结论 建立了通过单次细胞融合制备针对复合抗原的单克隆抗体制备技术,使单克隆抗体的产出率显著提高,制备周期明显缩短,为建立规模化单克隆抗体制备平台奠定基础。     

应用二维电泳和质谱技术鉴定乳腺癌相关蛋白

目的 通过比较人乳腺癌细胞MCF7和乳腺上皮细胞MCF10A的差异表达蛋白,以发现可能用于早期诊断的乳腺癌肿瘤标志物.方法 体外培养人乳腺癌细胞MCF7和乳腺上皮细胞MCF10A,提取细胞总蛋白,进行二维凝胶电泳并比较分析,选择在乳腺癌细胞MCF7中明显差异表达的蛋白点,进行质谱和生物信息学分析.结果 建立了MCF7和MCF10A两种细胞系的二维凝胶电泳图谱,平均蛋白质点数分别为(960±44)和(1128±29);对选择的35个差异表达蛋白质点进行质谱和生物信息学分析,鉴定了其中16个点,包括过氧化氢酶-6(PRDX6)、磷酸甘油酸激酶-1(PGK1)、60 kD热休克蛋白(CH60)、谷氨酰胺转移酶-2(TGM2)等.结论 乳腺癌细胞MCF7相对于乳腺上皮细胞MCF10A的差异表达蛋白可能作为乳腺癌早期诊断和预后评价的候选肿瘤标志物.     

丙泊酚对糖尿病大鼠海马组织蛋白质表达影响的蛋白组学研究

目的采用蛋白组学方法研究丙泊酚对2型糖尿病Goto-Kakizaki(GK)大鼠海马组织蛋白质表达的影响。方法将清洁级GK大鼠随机分为对照组(n=12)、丙泊酚麻醉组(n=12)和参数组(n=5),丙泊酚组和参数组腹腔注射丙泊酚100 mg/kg,在1 h和2 h后追加剂量50 mg/kg,维持麻醉3 h,对照组采用同样方法给予等体积生理盐水。丙泊酚组分别在麻醉结束后3、24、72 h和1周4个时间点随机选取3只大鼠,取海马组织,双向电泳法分离蛋白后进行凝胶扫描和图像分析,与相应时间点的对照组进行比较,选取4倍差异点进行质谱分析。观察参数组丙泊酚给药后0.5、1.5和2.5 h时间点血气分析指标的变化。结果与对照组相比,丙泊酚组麻醉后3 h发现7个蛋白点下调,24 h有3个蛋白点下调,72 h有2个蛋白点下调,1周则出现2个蛋白点上调,经质谱鉴定发现14个差异表达蛋白,涉及氧化还原、能量代谢、突触信息传递、细胞骨架和运动、细胞凋亡等生物学过程。血气分析指标监测结果显示:参数组丙泊酚给药后0.5 h与2.5 h时点的pH值和氧分压(PaO2)比较差异有统计学意义(P<0.05),但均在正常生理指标范围内。结论丙...     

SELDI protein profiling of dunning R-3327 derived cell lines: identification of molecular markers of prostate cancer progression

BACKGROUND: We recently demonstrated the protein expression profiling of Dunning rat tumor cell lines of varying metastatic potential (G (0%), AT-1 ( approximately 20%), and MLL (100%)) using SELDI-TOF-MS. As a parallel effort, we have been pursuing the identification of the protein(s) comprising the individual discriminatory "peaks" and evaluating their utility as potential biomarkers for prostate cancer progression. METHODS: To identify the observed SELDI-TOF-MS m/z (mass/charge) values with discriminatory expression between different sublines, we employed a combination of chemical pre-fractionation, liquid chromatography, gel electrophoresis and tandem mass spectroscopy. Identified proteins were then verified by immuno-assay and Western analysis. RESULTS: A 17.5 K m/z SELDI-TOF-MS peak was found to retain discriminatory value in each of two separate study-sets with an increased expression in the metastatic MLL line. Sequence identification and subsequent immunoassays verified that Histone H2B is the observed 17.5 K m/z SELDI peak. SELDI-based immuno-assay and Western Blotting revealed that Histone H2B is specifically over-expressed in metastatic MLL lines. CONCLUSIONS: SELDI-TOF MS analysis of the Dunning prostate cancer cell lines confirmed the consistent overexpression of a 17.5 K m/z peak in metastatic MLL subline. The 17.5 kDa protein from MLL has been isolated and identified as Histone H2B.     

Modified SH2 domain to phototrap and identify phosphotyrosine proteins from subcellular sites within cells

Spatial regulation of tyrosine phosphorylation is important for many aspects of cell biology. However, phosphotyrosine accounts for less than 1% of all phosphorylated substrates, and it is typically a very transient event in vivo. These factors complicate the identification of key tyrosine kinase substrates, especially in the context of their extraordinary spatial organization. Here, we describe an approach to identify tyrosine kinase substrates based on their subcellular distribution from within cells. This method uses an unnatural amino acid-modified Src homology 2 (SH2) domain that is expressed within cells and can covalently trap phosphotyrosine proteins on exposure to light. This SH2 domain-based photoprobe was targeted to cellular structures, such as the actin cytoskeleton, mitochondria, and cellular membranes, to capture tyrosine kinase substrates unique to each cellular region. We demonstrate that RhoA, one of the proteins associated with actin, can be phosphorylated on two tyrosine residues within the switch regions, suggesting that phosphorylation of these residues might modulate RhoA signaling to the actin cytoskeleton. We conclude that expression of SH2 domains within cellular compartments that are capable of covalent phototrapping can reveal the spatial organization of tyrosine kinase substrates that are likely to be important for the regulation of subcellular structures.     

Proteomic analysis identifies proteins associated with curcumin-enhancing efficacy of irinotecan-induced apoptosis of colorectal cancer LOVO cell

Objective: We wish to implement a proteomics-based approach to pick and identify the proteins associated with curcumin enhancing efficacy of irinotecan inducing apoptosis of colorectal cancer LOVO cells, and further explore their synergy mechanism by bioinformatics. Methods: A colorectal cancer cell line (LOVO cell) treated by curcumin combined with irinotecan in different ways respectively was used as our comparative model. Protein spots were analyzed through MALDI-TOF/TOF. The location and function of differential protein spots were analyzed through UniProt database. Protein-protein interactions were examined through String software. Results: A total of 54 protein spots differentially expressed with 1.5-fold difference were picked, 11 of which were repeated. They mainly were involved in intracellular calcium pathways, cellular respiratory chain pathway and intracellular redox reaction pathways of LOVO cell. According to the function of various protein points, combining with varying curves of protein points in each treatment groups, we selected five interesting protein spots, 4 of which exists Protein-protein interactions, and they were close to the formation and reduction of disulfides in intracellular endoplasmic reticulum (ER). Conclusion: We selected preliminary but comprehensive data about differential expression protein spots of LOVO cell. Among these, the five interesting differential expression protein spots identified in this study may provide new insight into LOVO cell therapeutic biomarkers. Curcumin may suppress GSTM5 expression to enhance the lethal effect of irinotecan on LOVO cells, and maybe their combination via the affection of PDI and PRDX4 to disturb the formation and reduction of disulfides results in inducing apoptosis of LOVO cell.     

Quantitative and targeted proteomics-based identification and validation of drug efficacy biomarkers

Proteomics refers to the large-scale study of proteins, providing comprehensive and quantitative information on proteins in tissue, blood, and cell samples. In many studies, proteomics utilizes liquid chromatography-mass spectrometry. Proteomics has developed from a qualitative methodology of protein identification to a quantitative methodology for comparing protein expression, and it is currently classified into two distinct methodologies: quantitative and targeted proteomics. Quantitative proteomics comprehensively identifies proteins in samples, providing quantitative information on large-scale comparative profiles of protein expression. Targeted proteomics simultaneously quantifies only target proteins with high sensitivity and specificity. Therefore, in biomarker research, quantitative proteomics is used for the identification of biomarker candidates, and targeted proteomics is used for the validation of biomarkers. Understanding the specific characteristics of each method is important for conducting appropriate proteomics studies. In this review, we introduced the different characteristics and applications of quantitative and targeted proteomics, and then discussed the results of our recent proteomics studies that focused on the identification and validation of biomarkers of drug efficacy. These findings may enable us to predict the outcomes of cancer therapy and drug-drug interactions with antibiotics through changes in the intestinal microbiome.     

Genetics and genomics of ankylosing spondylitis

Summary: Ankylosing spondylitis (AS) is a common, highly heritable arthropathy, the pathogenesis of which is poorly understood. The mechanism by which the main gene for the disease, HLA-B27, leads to AS is unknown. Genetic and genomic studies have demonstrated involvement of the interleukin-23 (IL-23) signaling pathway in AS, a finding which has stimulated much new research into the disease and has led to therapeutic trials. Several other genes and genetic regions, including further major histocompatibility complex (MHC) and non-MHC loci, have been shown to be involved in the disease, but it is not clear yet how they actually induce the condition. These findings have shown that there is a strong genetic overlap between AS and Crohn’s disease in particular, although there are also major differences in the genes involved in the two conditions, presumably explaining their different presentations. Genomic and proteomic studies are in an early phase but have potential both as diagnostic/prognostic tools and as a further hypothesis-free tool to investigate AS pathogenesis. Given the slow progress in studying the mechanism of association of HLA-B27 with AS, these may prove to be more fruitful approaches to investigating the pathogenesis of the disease.