The Role of Exosomes in Cancer Progression

Early detection, characterization and monitoring of cancer are possible by using extracellular vesicles (EVs) isolated from non-invasively obtained liquid biopsy samples. They play a role in intercellular communication contributing to cell growth, differentiation and survival, thereby affecting the formation of tumor microenvironments and causing metastases. EVs were discovered more than seventy years ago. They have been tested recently as tools of drug delivery to treat cancer. Here we give a brief review on extracellular vesicles, exosomes, microvesicles and apoptotic bodies. Exosomes play an important role by carrying extracellular nucleic acids (DNA, RNA) in cell-to-cell communication causing tumor and metastasis development. We discuss the role of extracellular vesicles in the pathogenesis of cancer and their practical application in the early diagnosis, follow up, and next-generation treatment of cancer patients.     

纳米掺锶羟基磷灰石的制备及其吸附性能研究

采用溶胶-凝胶-超临界流体干燥法制备了粒径在100 nm以下的纳米掺锶羟基磷灰石(SrHAP),以牛血清白蛋白(BSA)为吸附目标,研究了纳米SrHAP的吸附性能.结果发现在偏酸性条件下,纳米SrHAP比纳米HAP对BSA的吸附量大,表明掺锶后吸附性能提高;但在碱性条件下,纳米SrHAP对BSA的吸附量减小.纳米SrHAP对BSA的吸附是个快速吸附过程,增加Sr/[Ca Sr]原子比XSr和BSA的起始浓度有利于吸附,升高温度不利于吸附.     

复相乳化法制备海藻酸钙微球及其释放行为

采用复相乳化法制备了载牛血清白蛋白(BSA)的海藻酸钙微球,通过正交实验和单因素分析,以BSA包埋率、微球的载药率和平均粒径为考察指标,优化了该方法的制备参数,使最终制备的微球平均粒径小于10 mm,球形度较好,包埋率约70%,载药率达4%. 随着海藻酸钠质量分数的降低和BSA质量的增大,微球的包埋率下降、载药率升高、平均粒径减小. 微囊化BSA的体外释放曲线表明,该系统存在pH响应特性,尤其在磷酸缓冲液中,被包埋BSA的释放速率较快. 电泳结果表明,BSA的分子结构并未受制备过程的影响. 因此,该微囊化方法有望用于蛋白类药物的控释制剂,使其免受胃酸等的破坏,达到肠部释药的目的.     

TAPPI JOURNAL 2018年第10期目次

本实验建立在之前对含淀粉乳胶涂料的流变特性和动态保水性的研究成果基础之上。前期研究表明,淀粉胶乳的流变性和动态保水性不同于传统熟化涂布淀粉。本实验采用血清置换法研究了水膨胀淀粉纳米粒子的基本性能及其胶体行为。结果表明,淀粉胶乳是由微粒和少量可溶性聚合物组成的复杂体系。提高交联度会减少可溶性组分,并降低分散黏度。实验室圆柱形涂布机形成的涂层显示,丁苯胶乳具有可塑性,在压光过程中起到润滑剂的作用,有助于提高纸张光泽度。将生物胶乳与羟乙基淀粉（接枝聚合物）交联可以提高涂料的保水性,但是低交联Bio-A的使用则会降低涂布纸的光泽度。     

Serum Amyloid A3 Promoter-Driven Luciferase Activity Enables Visualization of Diabetic Kidney Disease

The early detection of diabetic nephropathy (DN) in mice is necessary for the development of drugs and functional foods. The purpose of this study was to identify genes that are significantly upregulated in the early stage of DN progression and develop a novel model to non-invasively monitor disease progression within living animals using in vivo imaging technology. Streptozotocin (STZ) treatment has been widely used as a DN model; however, it also exhibits direct cytotoxicity to the kidneys. As it is important to distinguish between DN-related and STZ-induced nephropathy, in this study, we compared renal responses induced by the diabetic milieu with two types of STZ models: multiple low-dose STZ injections with a high-fat diet and two moderate-dose STZ injections to induce DN. We found 221 genes whose expression was significantly altered during DN development in both models and identified serum amyloid A3 (Saa3) as a candidate gene. Next, we applied the Saa3 promoter-driven luciferase reporter (Saa3-promoter luc mice) to these two STZ models and performed in vivo bioluminescent imaging to monitor the progression of renal pathology. In this study, to further exclude the possibility that the in vivo bioluminescence signal is related to renal cytotoxicity by STZ treatment, we injected insulin into Saa3-promoter luc mice and showed that insulin treatment could downregulate renal inflammatory responses with a decreased signal intensity of in vivo bioluminescence imaging. These results strongly suggest that Saa3 promoter activity is a potent non-invasive indicator that can be used to monitor DN progression and explore therapeutic agents and functional foods.     

Gangliosides as Biomarkers of Human Brain Diseases: Trends in Discovery and Characterization by High-Performance Mass Spectrometry

Gangliosides are effective biochemical markers of brain pathologies, being also in the focus of research as potential therapeutic targets. Accurate brain ganglioside mapping is an essential requirement for correlating the specificity of their composition with a certain pathological state and establishing a well-defined set of biomarkers. Among all bioanalytical methods conceived for this purpose, mass spectrometry (MS) has developed into one of the most valuable, due to the wealth and consistency of structural information provided. In this context, the present article reviews the achievements of MS in discovery and structural analysis of gangliosides associated with severe brain pathologies. The first part is dedicated to the contributions of MS in the assessment of ganglioside composition and role in the specific neurodegenerative disorders: Alzheimer’s and Parkinson’s diseases. A large subsequent section is devoted to cephalic disorders (CD), with an emphasis on the MS of gangliosides in anencephaly, the most common and severe disease in the CD spectrum. The last part is focused on the major accomplishments of MS-based methods in the discovery of ganglioside species, which are associated with primary and secondary brain tumors and may either facilitate an early diagnosis or represent target molecules for immunotherapy oriented against brain cancers.     

恶性骨肿瘤血清的吸收光谱研究

运用分光光度计对正常与恶性骨肿瘤患者的血清进行光谱检测,把这些光谱数据进行 统计与分析,发现两者的差异,为医生快速确诊恶性骨肿瘤又提供了一种新的途径。     

一种席夫碱铋配合物的合成及其与牛血清白蛋白的相互作用

在非水体系中,以邻香草醛缩甘氨酸席夫碱与8-羟基喹啉、无水氯化铋合成一种三元配合物,通过元素分析、热分析、光谱分析等表征手段,确定其化学组成为[Bi(C_(10)H_(10_NO_4)(C_9H_6NO)_2]。席夫碱以酚羟基中的氧和C=N双键中的氮与铋(Ⅲ)成键,8-羟基喹啉以氧、氮与铋(Ⅲ)双齿配位,形成五元螯环。采用荧光法研究配合物与牛血清白蛋白(BSA)在不同温度下的相互作用,可知发生静态荧光猝灭,配合物与BSA以摩尔比1∶1结合形成复合物,结合常数为6.21×10~4L/mol,ΔH和ΔS均大于0,说明结合力主要为疏水作用;同步荧光扫描发现色氨酸残基的发射波长红移,表明复合物的形成导致BSA的构象发生了变化。     

基于质谱多反应监测技术（MRM）的蛋白质定量策略及其在肝癌生物标志物研究中的应用

肝癌是一种严重危害人类健康的恶性肿瘤,在中国占癌症死亡率的第二位,年死亡率约为20.37/10万^[1]。肝癌的早期发现是提高疗效延长患者生存时间的关键。寻找和研究特异性强、灵敏度高的肝癌生物标志物蛋白质作为肝癌的早期诊断或预警对于改善肝癌早期诊断率低的状况尤为重要。近几年来,基于质谱技术的蛋白质组学发展加快了生物标志物的研究进程^[2]。采用差异蛋白质组技术,通过比较健康和疾病状况下的蛋白质表达量变化,能获得大量与肝癌发生、发展相关的生物标志物候选蛋白质。然而,从这些候选蛋白质列表中,筛选与疾病发生发展更为密切的生物标志物,确证其在临床检测中的特异性和灵敏度却成为目前生物标志物研究流程中的瓶颈^[3]。传统的生物标志物确证的主要方法是基于免疫学原理的Western-blot和ELISA,由于特异性抗体获取困难制备周期长,使大量生物标志物候选蛋白质确证工作受到限制^[4]。而发展基于质谱MRM技术的蛋白质生物标志物候选蛋白质的定量验证策略,不需要进行特异性抗体的合成,为解决验证工作的瓶颈提供了一种新思路^[5]。 Vitronectin蛋白和clusterin蛋白在各种恶性肿瘤的发生、发展中起到重要作用,并且也有研究报道认为这两种蛋白质在血清中的表达水平与肝功能受损密切相关。在本研究中,通过采用18O稳定同位素标记方法合成肽段内标并结合MRM质谱检测技术,建立了一种方便快捷的蛋白质绝对定量方法并用于以上两种生物标志物候选蛋白质在肝癌血清中的定量确证。首先针对血清样品干扰组分多和动态范围宽的特点,优化质谱MRM检测条件,引入丙酮沉淀技术改善样品预处理步骤,设计优化的液相色谱分离条件,最终满足了多个血清样本的高通量测定要求。然后,考察了定量方法的可靠性,包括特异性、精密度、准确度、预处理回收率、测定重复性以及定量线性。方法学验证结果显示,在0.4~40 fmol•µL^－1的浓度变化范围内定量测定线性相关性良好,r2值大于0.99。蛋白质最低定量限为0.4 fmol•µL^－1。精密度RSD＜11.96%,准确度RE%＜20%。预处理回收率大于87%,测定重复性RSD＜6.87%。最后,采用建立的方法进行了20例临床血清样本的检测,其中10例健康血清,10例肝癌血清。两组定量数据的统计分析采用非参数统计方法Mann-Whitney检验。在血清样品中测定的vitronectin 和clusterin浓度变化区间分别为 48.28~265.45 mg•L^－1和49.41~136.93 mg•L^－1。统计结果显示两种蛋白质在肝癌组血清样品中浓度呈下调变化（p＝0.049;p＝0.002）,为进一步开展大样本的临床验证提供了基础。