ROR蛋白在癌症中的研究进展

ROR蛋白家族包含受体酪氨酸激酶ROR1和ROR2,作为Wnt受体,它们对于非经典Wnt信号通路至关重要,并与癌细胞增殖存活、侵袭转移和治疗抵抗密切相关。ROR蛋白在大多数成人健康组织中几乎不表达,但在一些癌症中却有较高的表达水平。有趣的是,两种ROR蛋白可能在肿瘤中发挥不同的作用, ROR1主要促进肿瘤发生,而ROR2在不同类型的肿瘤中促进或抑制肿瘤进展。目前这两种受体作为潜在的治疗靶点已经引起了人们的兴趣,该文总结了ROR蛋白的结构学特征及其在不同组织中的表达情况。此外,该文还回顾了ROR蛋白调控的生物学过程和信号通路,解释了其在癌症中发挥的重要作用。最后汇总了目前处于临床试验阶段的靶向ROR蛋白的生物药包括单抗、双抗、抗体偶联药物等。     

Ang-Tie轴在血管和淋巴系统相关疾病中作用的研究进展

形成血管和淋巴管内层的内皮细胞是脉管系统的重要组成部分,并参与血管和淋巴系统疾病的发病机制。内皮细胞上的血管生成素(Angiopoietin,Ang)-具有免疫球蛋白和表皮生长因子同源性结构域的酪氨酸蛋白激酶(Tyrosine kinase receptors with immunoglobulin and EGF homology domains,Tie)轴是除了血管内皮生长因子受体途径外胚胎心血管和淋巴发育所必需的第二种内皮细胞特异性配体-受体信号传导系统。Ang-Tie轴参与调节产后血管生成与重塑、血管通透性和炎症,以维持血管平衡,因此,该系统在许多血管和淋巴系统疾病中发挥重要的作用。针对近年来Ang-Tie轴在血管和淋巴系统相关疾病中作用的研究进展,文中系统论述了Ang-Tie轴在炎症诱导的血管通透性、血管重塑、眼部新生脉管、剪切应力反应、动脉粥样硬化和肿瘤血管生成和转移中的作用,并总结了涉及Ang-Tie轴的相关治疗性抗体、重组蛋白和小分子药物。     

受体酷氨酸激酶—Ras—MPAK信号转导途径研究进展

细胞怎样将外界刺激信息传递到细胞核内，一直是人们十分关心并不断探索的问题。最近，对生长因子影响细胞增殖的信号转导途径有了较明显的认识，它包括生长因子受体、接头蛋白、鸟螵呤核苷酸释放因子、Ｒａｓ蛋白及ＭＡＰ激酶级联系统。对该信号途径中某些成员的性质及作用机理的研究也取得了一定进展。     

酪氨酸磷酸化蛋白质组学技术研究进展及其在生物医学研究中的应用

在酪氨酸磷酸化蛋白质组学的研究过程中,酪氨酸磷酸化位点的富集是最重要的一步。目前常用的富集方法是抗体亲和富集或SH2 superbinder富集。此外,通过质谱与生物信息学等技术,可实现大规模酪氨酸磷酸化位点的鉴定。对酪氨酸磷酸化蛋白质组学进行深度覆盖研究,揭示癌症发生发展过程中失调的激酶,将有助于深入理解癌症的发生发展过程;且由于75%的致癌基因是酪氨酸激酶基因,酪氨酸激酶抑制剂作为抗癌药物受到了越来越多的关注。应用酪氨酸磷酸化蛋白质组学技术,可以鉴定与癌症等重大疾病相关的酪氨酸激酶,从而帮助找到酪氨酸激酶抑制剂。总之,酪氨酸磷酸化蛋白质组学技术可以在酪氨酸激酶鉴定、酪氨酸激酶抑制剂研究及酪氨酸磷酸化信号通路研究等生物医学领域中得到很好的应用。     

心血管疾病中的蛋白质硝基化

蛋白质硝基化一般是指蛋白质中的酪氨酸硝基化成3-硝基酪氨酸,是与氧化应激密切相关的蛋白质翻译后修饰。蛋白质硝基化现象在心血管疾病中普遍存在,但其对病理生理的确切影响尚不清楚。对它的进一步研究,有待于选择性硝基化方法的发现和更灵敏的检测技术的开发。     

FLT3／FLK2：酪氨酸激酶受体家族新成员

属于Ⅲ类酪氨酸激酶受体家族成员的ＦＬＴ３／ＦＬＫ２已分别在人和小鼠得到克隆和表达。该受体在造血早期干祖细胞上表达较丰富，在其他组织也见有表达。小鼠ＦＬＴ３／ＦＬＫ２ｃＤＮＡ长３４５３ｂｐ，编码９９０ａａ的多肽。人与小鼠ＦＬＴ３／ＦＬＫ２的蛋白质序列有８６％同源。     

Axl受体酪氨酸激酶家簇的研究进展

Ａｘｌ家族是一个比较新的受体酪氨酸激酶家族,成员包括Ａｘｌ、Ｍｅｒ及Ｒｓｅ等几个分子、结构很特征;胞浆区与神经细胞粘附分子结构相似,胞膜外区具备酪氨酸激酶活性,这类分子在一此正常组织,恶变组织中都有表达,研究发现它们在组织的成长,发育及恶变中都有一定作用。     

ROR2在骨肉瘤细胞和组织中的表达及其意义

目的：研究ROR2在骨肉瘤细胞及组织中的表达情况,探讨其表达的临床意义。方法：使用Western-blotting实验方法检测骨肉瘤及骨软骨瘤新鲜原发灶标本中ROR2表达情况;使用免疫组化方法检测骨肉瘤及骨软骨瘤原发灶标本中ROR2表达情况并结合临床资料了解其临床意义;使用RT-PCR实验方法检验SaoS-2骨肉瘤细胞中ROR2mRNA表达情况。结果：①通过免疫组织化学的方法检测骨肉瘤标本ROR2阳性表达率为70.91%,骨软骨瘤标本ROR2阳性表达率为20.00%,两者阳性表达率有显著性差异（x2=12.73 P〈0.05）。②Western-blotting实验检测新鲜骨软骨瘤和新鲜骨肉瘤组织中ROR2蛋白表达有显著性差异（P〈0.05）。③RT-PCR实验检测SaoS-2骨肉瘤细胞株中ROR2基因表达阳性。④检测在有转移的骨肉瘤患者标本中ROR2的阳性表达率为100.00%,在无肿瘤转移患者标本中阳性表达率为61.91%,两者表达阳性率有显著性差异（x2=5.26 P〈0.05）。⑤ROR2在骨肉瘤Enneking分期Ⅰ期表达阳性率为22.22%（2/9）,Ⅱ期表达阳性率为72.73%（24/33）,Ⅲ期表达阳性率为100.00%（13/13）。Ⅰ期与Ⅱ期间有显著性差异（x2=5.66 P〈0.05）,Ⅰ期与Ⅲ期间有显著性差异（x2=11.46 P〈0.05）,而Ⅱ期与Ⅲ期间无显著性差异（x2=2.85 P〉0.05）。结论：ROR2蛋白和基因在骨肉瘤组织及细胞中有较强表达。鉴于ROR2对于骨骼发育的影响及其通过WNT信号通路调节成骨细胞增殖及分化的生物学特点使得我们怀疑ROR2可能在骨肉瘤的发生发展过程中具有一定的作用,其可能促进了骨肉瘤的发生发展及恶性生物学行为。     

Apelin 在心血管疾病中的研究进展

Apelin是APJ(angiotensin II protein J)的一个配体,是一种重要的生理调节肽。Apelin-APJ系统在心血管系统存在广泛的作用,参与高血压、冠心病、心力衰竭及心房纤颤等多种疾病的病理生理过程,本文就apelin的生物学特性及与多种心血管疾病的关系作一综述。     

Sprouty2 and Sprouty4 are essential for embryonic morphogenesis and regulation of FGF signaling

Sprouty genes encode cytoplasmic membrane-associated proteins that inhibit receptor tyrosine kinase signaling. Four orthologs of Drosophila Sprouty (dSpry) (Sprouty1-4) have been identified in mammals. Physiological function of Sprouty1 and Sprouty2 has been investigated using gene targeting approaches, however to date detailed examination of Sprouty4 knockout (KO) mice has not been reported. In this study, Sprouty4 KO mice were generated and characterized. Although a significant fraction of Sprouty4 KO mice died shortly after birth due to mandible defects, the remainder were viable and fertile. Growth retardation was observed for most Sprouty4-deficient mice, with nearly all Sprouty4 KO mice having polysyndactyly. ERK activation was sustained in Sprouty4 KO mouse embryonic fibroblasts (MEFs) in response to FGF, but not to EGF. Sprouty2 and Sprouty4 double KO (DKO) mice were embryonic lethal and showed severe defects in craniofacial, limb, and lung morphogenesis. These findings suggest both redundant and non-redundant functions for Sprouty2 and Sprouty4 on embryonic development and FGF signaling.     

Sprouty genes are essential for the normal development of epibranchial ganglia in the mouse embryo

Fibroblast growth factor (FGF) signalling has important roles in the development of the embryonic pharyngeal (branchial) arches, but its effects on innervation of the arches and associated structures have not been studied extensively. We investigated the consequences of deleting two receptor tyrosine kinase (RTK) antagonists of the Sprouty (Spry) gene family on the early development of the branchial nerves. The morphology of the facial, glossopharyngeal and vagus nerves are abnormal in Spry1−/−;Spry2−/− embryos. We identify specific defects in the epibranchial placodes and neural crest, which contribute sensory neurons and glia to these nerves. A dissection of the tissue-specific roles of these genes in branchial nerve development shows that Sprouty gene deletion in the pharyngeal epithelia can affect both placode formation and neural crest fate. However, epithelial-specific gene deletion only results in defects in the facial nerve and not the glossopharyngeal and vagus nerves, suggesting that the facial nerve is most sensitive to perturbations in RTK signalling. Reducing the Fgf8 gene dosage only partially rescued defects in the glossopharyngeal nerve and was not sufficient to rescue facial nerve defects, suggesting that FGF8 is functionally redundant with other RTK ligands during facial nerve development.     

Activation of Ras-ERK pathway by Fgf8 and its downregulation by Sprouty2 for the isthmus organizing activity

In the previous studies, we showed that strong Fgf8 signaling activates the Ras-ERK pathway to induce cerebellum. Here, we show importance of negative regulation following activation of this pathway for proper regionalization of mesencephalon and metencephalon in chick embryos. ‘Prolonged’ activation of ERK by misexpression of Fgf8b and dominant-negative Sprouty2 (dnSprouty2) did not change the fate of the mesencephalic alar plate. Downregulation of ERK activity using an MEK inhibitor, U0126, or by tetracycline-dependent Tet-off system after co-expression of Fgf8b and dnSprouty2 forced the mesencephalic alar plate to differentiate into cerebellum. We then paid attention to Mkp3. After misexpression of dnMkp3 and Fgf8b, slight downregulation of ERK activity occurred, which may be due to Sprouty2, and the mesencephalon transformed to the isthmus-like structure. The results indicate that ERK must be once upregulated and then be downregulated for cerebellar differentiation and that differential ERK activity level established by negative regulators receiving Fgf8 signal may determine regional specificity of mesencephalon and metencephalon.     

Sprouty1 and Sprouty2 limit both the size of the otic placode and hindbrain Wnt8a by antagonizing FGF signaling

Multiple signaling molecules, including Fibroblast Growth Factor (FGF) and Wnt, induce two patches of ectoderm on either side of the hindbrain to form the progenitor cell population for the inner ear, or otic placode. Here we report that in Spry1, Spry2 compound mutant embryos (Spry1^−/−; Spry2^−/− embryos), the otic placode is increased in size. We demonstrate that the otic placode is larger due to the recruitment of cells, normally destined to become cranial epidermis, into the otic domain. The enlargement of the otic placode observed in Spry1^−/−; Spry2^−/− embryos is preceded by an expansion of a Wnt8a expression domain in the adjacent hindbrain. We demonstrate that both the enlargement of the otic placode and the expansion of the Wnt8a expression domain can be rescued in Spry1^−/−; Spry2^−/− embryos by reducing the gene dosage of Fgf10. Our results define a FGF-responsive window during which cells can be continually recruited into the otic domain and uncover SPRY regulation of the size of a putative Wnt inductive center.     

Structure of native oligomeric Sprouty2 by electron microscopy and its property of electroconductivity

Receptor tyrosine kinases (RTKs) regulate many cellular processes, and Sprouty2 (Spry2) is known as an important regulator of RTK signaling pathways. Therefore, it is worth investigating the properties of Spry2 in more detail. In this study, we found that Spry2 is able to self-assemble into oligomers with a high-affinity KD value of approximately 16 nM, as determined through BIAcore surface plasmon resonance analysis. The three-dimensional (3D) structure of Spry2 was resolved using an electron microscopy (EM) single-particle reconstruction approach, which revealed that Spry2 is donut-shaped with two lip-cover domains. Furthermore, the method of energy dispersive spectrum obtained through EM was analyzed to determine the elements carried by Spry2, and the results demonstrated that Spry2 is a silicon- and iron-containing protein. The silicon may contribute to the electroconductivity of Spry2, and this property exhibits a concentration-dependent feature. This study provides the first report of a silicon- and iron-containing protein, and its 3D structure may allow us (1) to study the potential mechanism through the signal transduction is controlled by switching the electronic transfer on or off and (2) to develop a new type of conductor or even semiconductor using biological or half-biological hybrid materials in the future.     

In non‐small cell lung cancer mitogenic signaling leaves Sprouty1 protein levels unaffected

Sprouty1 protein belongs to a family of receptor tyrosine kinase‐mediated signaling inhibitors, whose members are usually regulated by growth factors to form a negative feedback loop. Correspondingly fluctuations of Sprouty1 mRNA in response to single growth factors have been observed. In this report, we investigate Sprouty1 protein levels and show that in non‐small cell lung carcinoma‐derived cells, the expression levels are unaffected by the serum content in the cellular environment. Although cells harboring K‐Ras mutations express insignificant higher Sprouty1 levels, ectopic expression of constitutive active Ras in normal human lung fibroblasts fails to augment Sprouty1 protein content. Furthermore, serum starvation for three days has no influence on Sprouty1 expression and addition of serum or of singular growth factors leaves Sprouty protein levels unchanged. Cell cycle analysis reveals that Sprouty1 levels remain constant throughout the whole cell cycle. These data demonstrate that Sprouty1 expression is not connected with mitogenic signaling and cell proliferation. Copyright © 2013 John Wiley & Sons, Ltd.     

Synergistic activity of Sef and Sprouty proteins in regulating the expression of Gbx2 in the mid-hindbrain region

Sef and Sprouty proteins function as feedback antagonists of fibroblast growth factor (Fgf) signaling in zebrafish embryos. To study the role of Sef in mice, we generated Sef homozygous mutant animals. These animals are viable and show normal expression of mid-hindbrain genes at embryonic days 8.5 and 9.5. To investigate the possibility of functional synergism between Sef and Sprouty proteins, we electroporated Sprouty2(Y55A), which functions in a dominant-negative manner in tissue culture cells into the mid-hindbrain region of wildtype and Sef mutant embryos. The expression pattern of Gbx2, a downstream target of Fgf signaling, was expanded or shifted in electroporated embryos, and this effect was significantly enhanced in the Sef mutant background. Altogether, our results demonstrate that Sef and Sproutys function synergistically to regulate Gbx2 expression in the anterior hindbrain.     

KAI1/CD82 suppresses hepatocyte growth factor- induced migration of hepatoma cells via upregulation of Sprouty2

We conducted a study concerning the suppressive mechanism of KAI1/CD82 on hepatoma cell metastasis.Hepatocyte growth factor(HGF)induces the migration of hepatoma cells through activation of cellular sphingosine kinase 1(SphK1).Adenovirus-mediated gene transfer of KAI1(Ad-KAI1)downregulates the SphK1 expression and suppresses the HGF-induced migration of SMMC-7721 human hepatocellcular carcinoma cells.Overexpression of KAI1/CD82 significantly elevates Sprouty2 at the protein level.Ablation of Sprouty2 with RNA interference can block the KAI1/CD82-induced suppression of hepatoma cell migration and downregulation of SphK1 expression.It is demonstrated that KAI1/CD82 suppresses HGF-induced migration of hepatoma cells via upregulation of Sprouty2.