Expression and structural diversity of the lipopolysaccharide of Haemophilus influenzae: Implication in virulence

Lipopolysaccharide (LPS) is a major virulence determinant of the human bacterial pathogen Haemophilus influenzae. A characteristic feature of H. influenzae LPS is the extensive intra- and inter-strain heterogeneity of glycoform structure which is key to the role of the molecule in both commensal and disease-causing behaviour of the bacterium. Through the combination of genetics and detailed structural analyses, H. influenzae is an exemplar Gram-negative bacterium for which now the most extensive and detailed LPS structural data and functional correlates are available. LPS from H. influenzae consists of a conserved glucose-substituted triheptosyl inner-core moiety l-α-d-Hepp-(1→2)-[PEtn→6]-l-α-d-Hepp-(1→3)-[β-d-Glcp-(1→4)]-l-α-d-Hepp linked to lipid A via Kdo 4-phosphate. The inner-core unit provides the template for attachment of oligosaccharide- and non-carbohydrate substituents. Here, the structure, genetics and expression of LPS glycoforms in the outer core are reviewed as well as their implication on virulence.     

The effect of interleukin-17F on vasculogenic mimicry in oral tongue squamous cell carcinoma

Oral tongue squamous cell carcinoma (OTSCC) is one of the most common cancers worldwide and is characterized by early metastasis and poor prognosis. Recently, we reported that extracellular interleukin-17F (IL-17F) correlates with better disease-specific survival in OTSCC patients and has promising anticancer effects in vitro. Vasculogenic mimicry (VM) is the formation of an alternative vasculogenic system by aggressive tumor cells, which is implicated in treatment failure and poor survival of cancer patients. We sought to confirm the formation of VM in OTSCC and to investigate the effect of IL-17F on VM formation. Here, we showed that highly invasive OTSCC cells (HSC-3 and SAS) form tube-like VM on Matrigel similar to those formed by human umbilical vein endothelial cells. Interestingly, the less invasive cells (SCC-25) did not form any VM structures. Droplet-digital PCR, FACS, and immunofluorescence staining revealed the presence of CD31 mRNA and protein in OTSCC cells. Additionally, in a mouse orthotopic model, HSC-3 cells expressed VE-cadherin (CD144) but lacked Von Willebrand Factor. We identified different patterns of VM structures in patient samples and in an orthotopic OTSCC mouse model. Similar to the effect produced by the antiangiogenic drug sorafenib, IL-17F inhibited the formation of VM structures in vitro by HSC-3 and reduced almost all VM-related parameters. In conclusion, our findings indicate the presence of VM in OTSCC and the antitumorigenic effect of IL-17F through its effect on the VM. Therefore, targeting IL-17F or its regulatory pathways may lead to promising therapeutic strategies in patients with OTSCC.     

NOTCH4基因表达对肝细胞癌血管生成拟态形成的影响

目的研究NOTCH4基因表达对肝细胞癌血管生成拟态(VM)形成的影响。方法收集2010年-2014年间85例病理确诊为肝细胞癌的组织标本,免疫组织化学染色及PAS/CD31双染检测NOTCH4表达与VM的相关性;在体外三维细胞培养体系中靶向抑制肝癌细胞NOTCH4的表达,观察其对VM管状结构形成的影响。采用Mann-Whitney U秩和检验和单因素方差分析处理数据。结果 VM阳性的组织标本中NOTCH4高表达(P=0.019);siRNA组相对于阴性对照组及空白对照组,NOTCH4基因的mRNA表达(P值分别为0.007、0.003)及蛋白表达(P值均为0.000)均明显下调,差异具有统计学意义;靶向抑制NOTCH4的表达影响肝癌细胞在三维细胞培养体系中VM管状结构的形成。结论 NOTCH4基因表达影响肝细胞癌中VM的形成,可能成为肝细胞癌抗血管生成治疗的新靶点。     

Endothelial-like malignant glioma cells in dynamic three dimensional culture identifies a role for VEGF and FGFR in a tumor-derived angiogenic response

Aims: Recent studies have observed that cells from high-grade glial tumors are capable of assuming an endothelial phenotype and genotype, a process termed ‘vasculogenic mimicry’ (VM). Here we model and manipulate VM in dynamic 3-dimensional (3D) glioma cultures. Methods: The Rotary Cell Culture System (RCCS) was used to derive large macroscopic glioma aggregates, which were sectioned for immunohistochemistry and RNA extracted prior to angiogenic array-PCR. Results: A 3D cell culture induced microenvironment (containing only glial cells) is sufficient to promote expression of the endothelial markers CD105, CD31 and vWF in a proportion of glioma aggregates in vitro. Many pro-angiogenic genes were upregulated in glioma aggregates and in primary explants and glioma cells were capable of forming tubular-like 3D structures under endothelial-promoting conditions. Competitive inhibition of either vascular endothelial growth factor or fibroblast growth factor receptor was sufficient to impair VM and downregulate the tumor-derived angiogenic response, whilst impairing tumor cell derived tubule formation. Glioma xenografts using the same cells reveal tumor-derived vessel-like structures near necrotic areas, consistent with widespread tumor-derived endothelial expression in primary glioma tissue. Conclusions: Our findings support studies indicating that tumor-derived endothelial cells arise in gliomas and describe a dynamic 3D culture as a bona fide model to interrogate the molecular basis of this phenomenon in vitro. Resistance to current anti-angiogenic therapies and the contribution of tumor derived endothelial cells to such resistance are amenable to study using the RCCS.     

Application of functional vincristine plus dasatinib liposomes to deletion of vasculogenic mimicry channels in triple-negative breast cancer

Standard chemotherapy cannot eradicate triple-negative breast cancer (TNBC) while the residual cancer cells readily form the vasculogenic mimicry (VM) channels, which lead to the relapse of cancer after treatment. In this study, the functional vincristine plus dasatinib liposomes, modified by a targeting molecule DSPE-PEG₂₀₀₀-c(RGDyK), were fabricated to address this issue. The investigations were performed on TNBC MDA-MB-231 cells and MDA-MB-231 xenografts in nude mice. The liposomes exhibited the superior performances in the following aspects: the enhancement of cellular uptake via targeted action; the induction of apoptosis via activation of caspase 8, 9, and 3, increased expression of Bax, decreased expression of Mcl-1, and generation of reactive oxygen species (ROS); and the deletion of VM channels via inhibitions on the VM channel indicators, which consisted of vascular endothelial-cadherin (VE-Cad), focal adhesion kinase (FAK), phosphatidylinositide 3-kinase (PI3K), and matrix metallopeptidases (MMP-2, and MMP-9). Furthermore, the liposomes displayed the prolonged circulation time in the blood, the increased accumulation in tumor tissue, and the improved therapeutic efficacy along with deletion of VM channels in the TNBC-bearing mice. In conclusion, the nanostructured functional drug-loaded liposomes may provide a promising strategy for the treatment of invasive TNBC along with deletion of VM channels.     

阿西替尼对人口腔黏膜黑色素瘤裸鼠移植瘤血管生成拟态的作用探讨

目的:探讨阿西替尼用于口腔黏膜黑色素瘤(oral mucosal melanoma, OMM）治疗的可行性。方法:取病理确诊的口腔黏膜黑色素瘤标本,构建病人源性小鼠移植瘤（patient-derived xenografts,PDX）模型。将PDX动物模型随机分为2组,分别给予阿西替尼和羧甲基纤维素钠处理,用药周期28 d。应用免疫组织化学染色和过碘酸雪夫反应双染法,检测各组肿瘤的血管拟态(vasculogenic mimicry,VM)、EphA2、MMP-2及HIF-1a等蛋白的表达。采用SPSS 23.0软件包对数据进行统计学分析。结果:与空白对照组相比,阿西替尼显著抑制肿瘤生长,VM数量、CD34⁺血管数量、EphA2及MMP-2蛋白表达水平显著降低;HIF-1a表达显著高于对照组。结论:阿西替尼对人口腔黏膜黑色素瘤小鼠具有较好的肿瘤生长抑制作用,主要机制可能为抗血管新生和VM形成。     

Hindwings are unnecessary for flight but essential for execution of normal evasive flight in Lepidoptera

In Lepidoptera, forewings and hindwings are mechanically coupled and flap in synchrony. Flight is anteromotoric, being driven primarily by action of the forewings. Here we report that lepidopterans can still fly when their hindwings are cut off, a procedure reducing their total wing surface, on average, by nearly one half. However, as we demonstrate by analysis of three-dimensional flight trajectories of a moth and a butterfly (Lymantria dispar and Pieris rapae), hindwing removal causes lepidopterans to incur a loss in both linear and turning acceleration, so that they are unable to exercise their normal flight maneuverability. Without hindwings they still are able to zigzag aerially (the ablation has no effect on their turning radius in flight) but at lesser speed and therefore less evasively. Consequently, hindwings in the expanded state in which they occur in lepidopterans seem to contribute in an essential way to lepidopteran survival. Moths in today's world, we argue, may rely on their evasive flight primarily to avoid capture by bats, whereas butterflies, which we propose advertise their evasiveness collectively through shared aposematism, may depend upon it primarily for defense against birds. Aerial agility thus may be the chief adaptive asset derived by lepidopterans from possession of oversize hindwings.     

血管生成拟态在消化道肿瘤中的研究进展

血管生成拟态是近几年来在发现的一种与经典的肿瘤血管生成途径完全不同、不依赖机体内皮细胞的全新肿瘤血管模式,他描述了高度侵袭性肿瘤细胞可以发生基因逆转,表达内皮细胞相关基因,在三维基质中培养时形成管状结构或网络样管道的特有能力.研究证实,与肿瘤生长、侵袭、转移及患者预后密切相关.本文就血管生成拟态的特点、发生机制、对肿瘤治疗的意义以及在消化道肿瘤中的研究进展等作一综述.