糖链变化对肿瘤转移的影响及在肿瘤疫苗中的应用

在许多恶性肿瘤中存在多种糖链结构的改变,这些变化在细胞整体水平与分子水平影响肿瘤的转移能力.现着重介绍近几年关于几种糖链变化对肿瘤转移能力影响的研究新发现,以及在此基础上发展的肿瘤疫苗治疗方法的研究进展.     

小檗碱调节己糖激酶Ⅱ抑制乳腺癌细胞糖酵解的作用研究

摘 要 目的：研究小檗碱对乳腺癌细胞糖酵解的干预作用及对己糖激酶Ⅱ的影响。方法: 分别采用人乳腺癌MDA MB 231,MCF 7细胞株,通过MTT实验, 考察小檗碱对乳腺癌细胞增殖的抑制作用,检测小檗碱干预后乳腺癌细胞中葡萄糖消耗及乳酸含量,评价小檗碱对乳腺癌细胞糖酵解的影响;检测乳腺癌细胞中ATP及NAD+/NADH含量,评价乳腺癌细胞能量供应情况;通过检测己糖激酶Ⅱ活性及蛋白定量,明确小檗碱对乳腺癌细胞己糖激酶的影响。结果: 小檗碱对人乳腺癌细胞株MDA MB 231,MCF 7细胞增殖,具有明显抑制作用,并呈浓度依赖性;小檗碱可以明显降低不同乳腺癌细胞株中葡萄糖消耗及乳酸含量,中高剂量组相较于对照组差异有统计学意义(P<0.05);同时相较于对照组,中高剂量组可明显降低细胞ATP含量,升高NAD+/NADH含量(P<0.05);此外小檗碱可以抑制乳腺癌细胞己糖激酶Ⅱ活性及其蛋白含量。结论: 小檗碱可以明显抑制乳腺癌细胞增殖,并抑制乳腺癌细胞糖酵解,降低其能量供应,同时明显抑制乳腺癌细胞中己糖激酶Ⅱ的表达。     

解开奇妙的生命现象糖链

在完成人类基因组的解读工作之后，生命科学的下一个重点研究对象之一就是所谓的“糖链”。糖链也是由四个字母组成的一种简单的密码DNA所决定的，但它携带着非常的复杂信息，对它的研究自然十分困难。但是，糖链不仅与我们的血型和受精过程有关，而且还与流行性感冒传染和癌细胞转移等诸多疾病的发病机制有着密切的联系。     

蔗糖铁中糖、铁复物降解特性研究

本文基于酸性条件下蔗糖铁复合物中糖、铁解离,利用其反应动力学建立了其数学模型,并将不同温度下反应体系溶液浊度、p H值相关联,计算出蔗糖铁解离反应的能量变化(ΔE)及游离糖缓冲系数(n)。结果表明:蔗糖铁中糖、铁的氢键键合特性,而对蔗糖铁复合物类药物的保存及其进一步深加工等有一定的理论指导意义。     

克糖特对糖尿病模型小鼠血糖的影响

目的:研究克糖特(KTF)对糖尿病模型小鼠血糖的影响,并初步探讨其降低小鼠血糖的作用机制。方法:建立链脲霉素(STZ)致糖尿病小鼠模型。将小鼠随机分为5组(n=10),分别用格列本脲(50 mg·kg~(-1))、高、中、低剂量克糖特和0.9%氯化钠溶液(0.1 ml/10g体重)灌胃15d。15d后测定正常小鼠的血糖水平,并在相应时间测定STZ致糖尿病小鼠模型空腹血糖(FBG)、药后2h血糖(2h BG)、胰岛素水平,同时对STZ所致糖尿病小鼠进行胰腺病理组织学检查。结果:克糖特对正常小鼠血糖水平无影响,能够显著降低STZ模型小鼠空腹血糖(与模型组比较降糖率可达24.39%,P<0.05～0.01)和药后2 h BG(P<0.05),明显提高胰岛素水平(P<0.05～0.01),保护胰岛β细胞。结论:克糖特对STZ引起的高血糖有较好的降糖作用,其作用机制可能与改善受损的胰岛细胞功能,促进胰岛素分泌有关。     

血清肿瘤标志物联合检测在胃癌诊断中的应用价值

目的探讨胃癌发生与血清肿瘤标志物癌胚抗原、糖链抗原19-9和糖链抗原72-4的关系以及其在临床诊断中的指导意义。方法我院采用电化学发光检测法对120例确诊为胃癌的患者血清中的肿瘤标志物糖链抗原72-4、糖链抗原19-9和癌胚抗原的含量进行了定量分析,同时选取了同一时期来我院的100例非肿瘤患者的血清作为对照研究。结果胃癌组患者癌胚抗原、糖链抗原19-9和糖链抗原72-4的检测敏感性分别为49.5%、36.5%和21.2%,100%、70.5%和92.3%分别为特异性。相比较手术前,手术后患者显著性下调癌胚抗原、糖链抗原19-9和糖链抗原72-4的水平。结论癌胚抗原、糖链抗原19-9和糖链抗原72-4在胃癌的临床诊断中敏感性较低,三者联合使用可显著增加临床的诊断准确性。     

枸杞糖缀合物和糖链对小鼠巨噬细胞功能的影响

目的确定巨噬细胞是枸杞糖缀合物和糖链免疫作用的靶细胞之一。方法应用中性红吞噬实验和鸡红细胞吞噬实验测定了枸杞糖缀合物LbGp4和糖链LbGp4-OL对小鼠腹腔巨噬细胞吞噬功能的影响;用硝酸根还原法、酶联免疫吸附实验(ELISA)和生物活性测定法测定了巨噬细胞产生一氧化氮(NO)、IL-1β和TNF-α含量和生物活性的变化。结果LbGp4和LbGp4-OL在(10~100)mg.L-1剂量范围内均可剂量依赖性地促进静息巨噬细胞吞噬中性红的能力,增加活化的巨噬细胞吞噬鸡红细胞的吞噬率和吞噬指数;增加巨噬细胞培养上清NO、IL-1β和TNF-α的浓度,并增强对L929细胞的杀伤活性,促进胸腺细胞的增殖反应。结论LbGp4和LbGp4-OL对静息和活化的腹腔巨噬细胞的吞噬功能具有明显的促进作用,对巨噬细胞产生NO、分泌IL-1β和TNF-α的含量和生物活性亦具有明显的促进作用,表明巨噬细胞是LbGp4和LbGp4-OL免疫作用的靶细胞之一。     

党参和甘草糖复合物对IEC-6细胞迁移和膜电位的影响

目的观察党参糖复合物和甘草糖复合物对小肠上皮细胞IEC-6迁移和细胞膜电位的影响,探讨益气健脾中药党参和甘草促进胃肠黏膜损伤修复的作用机制。方法在正常或钾通道抑制剂4-氨基吡啶(4-AP)负荷下,分别加入党参和甘草糖复合物(25~200 mg·L~(-1))与IEC-6细胞培养24 h,相差显微镜下观察细胞迁移数,流式细胞仪检测细胞膜电位。结果与细胞正常对照组比较,党参和甘草糖复合物(50和100 mg·L~(-1))可提高细胞迁移数(P<0.01,P<0.05)。与正常对照组比较,4-AP可减少细胞迁移数(P<0.01);与4-AP模型组比较,党参和甘草糖复合物(50~200 mg·L~(-1))可逆转4-AP所致的细胞迁移抑制(P<0.01)。流式细胞仪检测结果表明,与正常对照组比较,党参和甘草糖复合物(50 mg·L~(-1))可提高细胞膜电位(P<0.01),增加细胞膜超极化水平;与正常对照组比较,4-AP模型组细胞膜电位降低(P<0.01),增加细胞膜去极化水平;与4-AP模型组比较,党参和甘草糖复合物(100和200 mg·L~(-1))可逆转4-AP所致的细胞膜去极化(P<0.01)。结论党参和甘草促进胃肠黏膜损伤修复的作用机制,可能与其糖复合物影响小肠上皮细胞迁移的多胺介导钾通道激活信号通路有关。     

枸杞糖缀合物及糖链的化学结构与免疫活性

为研究枸杞多糖的化学结构 ,免疫活性并探讨其构效关系 ,应用色谱法 ,凝胶过滤法和十二烷基磺酸钠 聚丙烯酰胺凝胶电泳 (SDS PAGE)技术从枸杞粗多糖 (LBP)中分离纯化了 5个组分 (LBP1 LBP5) ,并进一步从LBP1,LBP3,LBP4中纯化得到组分均一的糖缀合物LbGp1,LbGp3和LbGp4及其糖链LbGp1 OL ,LbGp3 OL和LbGp4 OL ,用甲基化 ,部分酸水解和核磁共振 (NMR)技术基本阐明了其化学性质 ,糖组成 ,氨基酸组成及主要结构特征 ,并用小鼠脾细胞增殖反应研究免疫活性表明 ,6个样品均具有直接增强小鼠脾细胞增殖反应的作用 .结果提示 ,枸杞子中具有免疫活性的有效成分是一类结构复杂的糖缀合物 ,其糖链部分可能是其发挥免疫活性的主要活性结构 .     

糖链切除对IgG1型单抗结构及功能的影响

目的:分析IgG1型单抗中糖链切除对其结构与功能的影响。方法:分别测定糖链切除前后该抗体的圆二色谱、抗原结合能力以及体外补体依赖的细胞毒(CDC)活性,分析糖链切除对该单抗结构与功能的影响。结果:糖链切除后抗体的圆二色谱发生改变,抗原结合能力下降,体外CDC活性基本消失。结论:糖链是维持该IgG1型单抗正常的结构和功能的重要组成部分。     

钝顶螺旋藻糖缀合物SPPA-1的糖链化学结构研究

目的研究从钝顶螺旋藻中分离纯化得到的糖缀合物SPPA-1的糖链结构。方法应用了气相色谱、甲基化分析和1H,¹³CNMR及2DNMR技术研究糖链结构。结果SPPA-1的糖链是由单一葡萄糖组成,其重复单元是由1→4连接的葡萄糖糖残基组成的主链且具有分支。结论SPPA-1的糖链部分为一新的葡聚糖。     

Structure elucidation of glycan of glycoconjugate LbGp3 isolated from the fruit of Lycium barbarum L

The structure of the repeat unit of the glycan of glycoconjugate LbGp3 with pronounced immuno-activity, isolated from the fruit of Lycium barbarum L. was elucidated based on methylation analysis, partial acid hydrolysis and ¹H, ¹³C NMR spectroscopy of the original glycan and products of its partial hydrolysis.     

Design and optimization of 20-O-linked camptothecin glycoconjugates as anticancer agents.

To improve the biological profile of 20(S)-camptothecin, a novel class of 20-O-linked camptothecin glycoconjugates has been designed for preferential cellular uptake into tumor cells by an active transport mechanism. Such conjugates have been optimized for enhanced solubility, stabilization of the camptothecin lactone ring, sufficient hydrolytic and proteolytic stability, and for an overall improvement in tumor selectivity. The constitution of the peptide spacer has a major impact on stability and biological activity of the conjugates both in vitro and in vivo. Glycoconjugates 17-22 with valine residues at the linkage position to camptothecin are sufficiently stable and show good antitumor activity in vitro against HT29 and other tumor cell lines. Fluorescence microscopy and flow cytometry experiments indicate that glycoconjugates such as 19 are taken up into lysosomal compartments of the tumor cell line HT29 by an active transport mechanism. The steric configuration of the particular amino acid residues linked to the camptothecin moiety has a major impact on the in vivo activity of the corresponding glycoconjugates in the breast cancer xenograft MX-1 model. Inhibiting tumor growth by >96%, the glycoconjugates 19 and 21 show the best activity in this particular model and have been investigated more extensively. The glycoconjugate 19 compares favorably to topotecan 4 and glycoconjugate 21 with respect to toxicity against hematopoietic stem cells and hepatocytes. Based on its profile, 19 has been selected for clinical trials.     

Nano-LC and HPLC-chip-ESI-MS: an emerging technique for glycobioanalysis

In less than 5 years, an impressive number of methods based on nano-LC and HPLC-chip coupled online to MS were developed and implemented to comprehensively address structural heterogeneity of glycoconjugates and glycans in biological matrices. C18, graphitized carbon and amide-based stationary phases were adapted to nanoflow level and on chip format, leading to improved sensitivity of structural analysis and superior level of information on highly complex glycan and glycoconjugate mixtures. This review offers a summary of the recent progress in the application of nano-LC and HPLC-chip-MS in glycoanalytics of glycopeptides, glycoprotein glycans, glycosaminoglycans, oligosaccharides and glycosphingolipids.     

Therapeutically targeting protein–glycan interactions

Glycosylation is the most common form of post-translational modifications by which oligosaccharide side chains are covalently attached to specific residues of the core protein. Especially O-linked glycan structures like the glycosaminoglycans were found to contribute significantly to many (patho-)biological processes like inflammation, coagulation, cancer and viral infections. Glycans exert their function by interacting with proteins thereby changing the structure of the interacting proteins and consequently modulating their function. Given the complex nature of cell-surface and extracellular matrix glycan structures, this therapeutic site has been neglected for a long time, the only exception being the antithrombin III-glycan interaction which has been sucessfully targeted by unfractionated and low-molecular weight heparins for many decades. Due to the recent breakthrough in the ‘–ome’ sciences, among them proteomics and glycomics, protein–glycan interactions became more amenable for therapeutic approaches so that novel inhibitors of this interaction are currently in preclinical and clinical studies. An overview of current approaches, their advantages and disadvantages, is given and the promising potential of pharmacologically interfering with protein–glycan interactions is highlighted here.     

Role of glycosylation in the anticancer activity of antibacterial peptides against breast cancer cells

Antibacterial peptides (ABPs) with cancer-selective toxicity have received much more attention as alternative chemotherapeutic agents in recent years. However, the basis of their anticancer activity remains unclear. The modification of cell surface glycosylation is a characteristic of cancer cells. The present study investigated the effect of glycosylation, in particular sialic acid, on the anticancer activity of ABPs. We showed that aurein 1.2, buforin IIb and BMAP-28 m exhibited selective cytotoxicity toward MX-1 and MCF-7 breast cancer cells. The binding activity, cytotoxicity and apoptotic activity of ABPs were enhanced by the presence of O-, N-glycoproteins, gangliosides and sialic acid on the surface of breast cancer cells. Among N-, O-glycoproteins and ganglioside, O-glycoproteins almost had the strongest effect on the binding and cytotoxicity of the three peptides. Further, up-regulation of hST6Gal1 in CHO-K1 cells enhanced the susceptibility of cells to these peptides. Finally, the growth of MX-1 xenograft tumors in mice was significantly suppressed by buforin IIb treatment, which was associated with induction of apoptosis and inhibition of vascularization. These data demonstrate that the three peptides bind to breast cancer cells via an interaction with surface O-, N-glycoproteins and gangliosides. Sialic acids act as key glycan binding sites for cationic ABP binding to glycoproteins and gangliosides. Therefore, glycosylation in breast cancer cells plays an important role in the anticancer activity of ABPs, which may partly explain their cancer-selective toxicity. Anticancer ABPs with cancer-selective cytotoxicity will be promising candidates for anticancer therapy in the future.     

三阴性乳腺癌用药进展

三阴性乳腺癌是缺乏雌激素受体、孕激素受体和人类表皮生长因子受体-2的特殊类型的乳腺癌，相比其他乳腺癌亚型，其临床特征为预后较差、高侵袭性、高转移性以及高复发率。目前三阴性乳腺癌的早期治疗手段主要为蒽环类和紫杉烷类化学疗法，但容易产生耐药性；而且三阴性乳腺癌对一些现有的靶向药物和内分泌治疗药物敏感性也不高。因此本文在介绍目前三阴性乳腺癌涉及的临床用药的基础上，还对联合用药、新药研发进展作简要综述，为今后的用药提供思路。     

How to judge the association of postmenopausal hormone therapy and the risk of breast cancer

The relevance of postmenopausal hormone therapy (HT) for breast cancer risk has been long debated, although it is one of the most important barriers for women to accept HT. Various opinions have been reported from recent randomized clinical trials and epidemiological studies. These unanswered questions include: whether HT has a positive impact on breast cancer; whether risks of therapy with unopposed estrogen and combined estrogen-progestin are different; and whether different types and routes of estrogen and progestogens, as well as the duration and cessation of HT use, have different impacts on this disorder. Recently, there has been some good news such as the following: the currently available data do not provide sufficient evidence to prove a causal relationship between postmenopausal HT and breast cancer; breast cancer in postmenopausal women using HT usually has better prognosis than that of nonusers. In conclusion, HT is still the most effective method of relieving climacteric symptoms for many postmenopausal women. However, a possible risk of breast cancer associated with long-term HT usage should not be ignored. With respect to prevention of breast cancer, regular evaluation of individual breast cancer susceptibility and close follow-up through mammography and/or breast sonography are necessary strategies for the safety of HT use.     

Targeting IL-8 signalling to inhibit breast cancer stem cell activity

Although survival from breast cancer has improved significantly over the past 20 years, disease recurrence remains a significant clinical problem. The concept of stem-like cells in cancer has been gaining currency over the last decade or so, since evidence for stem cell activity in human leukaemia and solid tumours, including breast cancer, was first published. Evidence indicates that this sub-population of cells, known as cancer stem-like cells (CSCs), is responsible for driving tumour formation and disease progression. In breast cancer, there is good evidence that CSCs are intrinsically resistant to conventional chemo-, radio- and endocrine therapies. By evading the effects of these treatments, CSCs are held culpable for disease recurrence. Hence, in order to improve treatment there is a need to develop CSC-targeted therapies. Interleukin-8 (IL-8), an inflammatory cytokine, is upregulated in breast cancer and associated with poor prognostic factors. Accumulating evidence demonstrates that IL-8, through its receptors CXCR1/2, is an important regulator of breast CSC activity. Inhibiting CXCR1/2 signalling has proved efficacious in pre-clinical models of breast cancer providing a good rationale for targeting CXCR1/2 clinically. Here, we discuss the role of IL-8 in breast CSC regulation and development of novel therapies to target CXCR1/2 signalling in breast cancer.