活化白细胞黏附分子及其与肿瘤侵袭转移的关系

ALCAM主要表达在白细胞和胸腺上皮细胞,属于免疫球蛋白基因超家族的成员,是淋巴细胞抗原CD6的配基。ALCAM/CD166在多种肿瘤细胞表面高表达,参与肿瘤的发生发展。已通过体外试验和动物模型证实ALCAM/CD166对多种肿瘤生长和转移相关的肿瘤细胞特性具有调节作用;在人类肿瘤,ALCAM/CD166与乳腺癌、前列腺癌、食道癌、结肠癌及恶性黑色素瘤等肿瘤患者的生存率及预后密切相关。     

Frontline: Optimal T cell activation requires the engagement of CD6 and CD166

The T cell surface glycoprotein, CD6 binds CD166 in the first example of an interaction between a scavenger receptor cysteine-rich domain and an immunoglobulin-like domain. We report that in human these proteins interact with a K(D) =0.4-1.0 microM and K(off) > or =0.4-0.63 s(-1), typical of many leukocyte membrane protein interactions. CD166 also interacts in a homophilic manner but with around 100-fold lower affinity (K(D) =29-48 microM and K(off) > or = 5.3 s(-1)). At concentrations, that will block the CD6/CD166 interaction, soluble monomeric CD6 and CD166 inhibit antigen-specific human T cell responses. This is consistent with extracellular engagement between CD6 and CD166 being required for an optimal immune response.     

Recombinant full-length human IgG1s targeting hormone-refractory prostate cancer

We have used a naive human single-chain fragment variable (scFv) library as a source of random shape repertoire to directly probe the altered surface chemistry of tumor cells. We reported previously the identification of more than 90 internalizing phage monoclonal antibodies targeting prostate cancer cells, including those that are hormone refractory. In this report, we describe the conversion of a panel of those scFvs into full-length human immunoglobulins (IgGs) and show that tumor specificity is retained. We have further shown that antibodies isolated from a naive phage display library can nevertheless be of high affinity towards target tumor cells. In addition, full-length IgGs retain the functionality of parental scFvs including the ability to rapidly enter target cells through receptor-mediated endocytosis and thereby to mediate efficient and specific intracellular payload delivery to tumor cells. We have used recombinant IgGs to immunoprecipitate target antigens and analyzed their molecular composition by mass spectrometry. We have identified one target antigen as activated leukocyte cell adhesion molecule (ALCAM)/MEMD/CD166 and have further studied tissue specificity of this internalizing ALCAM epitope by immunohistochemistry. Our study shows that cell type-specific internalizing human antibody can be readily identified from a naive phage antibody display library, characterized with regards to sequence, affinity, tissue specificity, and antigen identity, and modified genetically and chemically to generate various forms of targeted therapeutics.     

CD6 monoclonal antibodies differ in epitope,kinetics and mechanism of action

CD6 is a type I T‐cell surface receptor that modulates antigen receptor signalling. Its activity is regulated by binding of its membrane proximal domain (domain 3) to a cell surface ligand, CD166. CD6 monoclonal antibodies (mAbs) specific for the membrane distal domain (domain 1) perturb CD6 function including itolizumab (Alzumab?), which has reached the clinic for treatment of autoimmune disease. We characterized molecular and functional properties of several CD6 mAbs including itolizumab to define potential mechanisms of action. Epitope mapping using the crystal structure of CD6 to design mutants identified two distinct binding sites on different faces of domain 1, one containing residue R77, crucial for MT605 and T12.1 binding and the other, E63, which is crucial for itolizumab and MEM98. Analysis of binding kinetics revealed that itolizumab has a lower affinity compared with other CD6 domain 1 mAbs. We compared potential agonistic (triggering) and antagonistic (blocking) properties of CD6 mAbs in assays where the mechanism of action was well defined. CD6 domain 1 and 3 mAbs were equally effective in triggering interleukin‐2 production by a cell line expressing a chimeric antigen receptor containing the extracellular region of CD6. CD6 domain 1 mAbs hindered binding of multivalent immobilized CD166 but were inferior compared with blocking by soluble CD166 or a CD6 domain 3 mAb. Characterization of CD6 mAbs provides an insight into how their functional effects in vivo may be interpreted and their therapeutic use optimized.     

Activated leukocyte cell adhesion molecule (ALCAM/CD166) expression in head and neck squamous cell carcinoma (HNSSC)

Activated leukocyte cell adhesion molecule (ALCAM/CD166) is expressed in a number of malignancies (e.g. prostate, breast, squamous cell carcinoma of the esophagus, lung and head and neck tumors). Based on studies in which ALCAM showed prognostic relevance in several carcinomas, it has been discussed as a potential therapeutic target. We evaluate its expression in head and neck squamous cell carcinomas (HNSCCs).     

Low activated leukocyte cell adhesion molecule expression is associated with advanced tumor stage and early prostate-specific antigen relapse in prostate cancer

Activated leukocyte cell adhesion molecule (CD166) is a member of the immunoglobulin superfamily and is aberrantly expressed in different tumors, including prostate cancer. To learn more on the prevalence and clinical significance of activated leukocyte cell adhesion molecule expression in prostate cancer, a tissue microarray containing 3261 primary prostate cancers treated by radical prostatectomy was used. A total of 2390 different prostate cancers were analyzed by immunohistochemistry in a tissue microarray format. Activated leukocyte cell adhesion molecule immunostaining in cancers was compared with clinical follow-up, which was available for 1746 patients. Membranous activated leukocyte cell adhesion molecule immunostaining was recorded in 1663 (69.6%) of cases. High activated leukocyte cell adhesion molecule expression levels were significantly associated with favorable tumor features (pT: P = .0015; pN: P = .0008; preoperative prostate-specific antigen: P = .0057) and a lower risk of a biochemical recurrence (P = .0067). Cytoplasmatic activated leukocyte cell adhesion molecule staining was usually associated with membranous staining. The small number of cancers with pure cytoplasmatic staining did not reveal any particularities with respect to clinical outcome or tumor phenotype. It is concluded that activated leukocyte cell adhesion molecule protein is almost always expressed in prostate cancer and that decreased levels of activated leukocyte cell adhesion molecule expression may lead to an aggressive behavior of tumor cells. The abundant presence of activated leukocyte cell adhesion molecule and its membranous localization in prostate cancer epithelium make activated leukocyte cell adhesion molecule a potentially attractive structure for targeted therapy.     

CD166 Expression, Characterization, and Localization in Salivary Epithelium: Implications for Function During Sialoadenitis

CD166 is an Ig superfamily molecule that binds homotypically to itself and heterotypically to CD6. Interactions between CD6 and CD166 are important during immune development and in alloreactivity. CD166 is expressed at increased levels in selected cancers and in rheumatoid arthritis synovium. Knowledge that CD166 was expressed in normal human salivary epithelium led to these studies of CD166 and CD6 in diseased mouse salivary glands, that resemble pathology seen in the human disease, Sjögren's syndrome. We showed that in mouse salivary epithelium CD166 was expressed but that expression of CD166 did not necessarily predict its function. Recombinant soluble CD6-Ig bound to CD6 ligands (CD6L) on transformed and freshly isolated salivary epithelial cells. Cross-blocking studies showed that binding of CD6-Ig to salivary epithelium was in part dependent on CD166, but that CD6-Ig binding may also involve additional CD6L. Binding of CD6-Ig was sensitive to trypsin digestion but resistant to digestion by collagenase and sialidase. Anti-CD166 ab precipitated CD166 from salivary epithelium pre- and post-treatment with the pro-inflammatory cytokine IFN-γ. In contrast CD6-Ig only precipitated CD166 from IFN-γ treated cells. More extensive colocalization between CD166 and the actin cytoskeleton was observed in sialoadenitis epithelium compared to control. We conclude that during sialoadenitis, CD166 undergoes a gain of function, resulting in closer association with the actin cytoskeleton and increased capacity to bind CD6. We suggest that altered CD166 function may contribute to the pro-inflammatory milieu during sialoadenitis seen in Sjögren's syndrome.     

Galectin-3和CD44v6在甲状腺癌中的表达及临床价值

为观察Galectin-3和CD44v6在甲状腺良、恶性结节中的表达差异,探讨其在甲状腺癌鉴别诊断中的临床价值,应用免疫组化方法检测30份甲状腺癌组织、38份甲状腺良性结节及29份正常甲状腺组织中Galectin-3和CD44v6的表达。结果显示,甲状腺癌组织中Galectin-3和CD44v6的阳性率均显著高于良性结节和正常甲状腺组织（P〈0．005）,其中乳头状癌和滤泡状腺癌的阳性率显著高于其它类型癌组织（P〈0．005）。结论：Galectin-3和CD44v6可以作为甲状腺癌鉴别诊断的较有价值的标志物。     

Reduced suppressive effect of CD4+CD25high regulatory T cells on the T cell immune response against myelin oligodendrocyte glycoprotein in patients with multiple sclerosis

Immunoregulatory T cells of (CD4+)CD25+ phenotype suppress T cell function and protect rodents from organ-specific autoimmune disease. The human counterpart of this subset of T cells expresses high levels of CD25 and its role in human autoimmune disorders is currently under intense investigation. In multiple sclerosis (MS), a chronic inflammatory disease of the central nervous system (CNS), the activation of circulating self-reactive T cells with specificity for myelin components is considered to be an important disease initiating event. Here, we investigated whether MS is associated with an altered ability of (CD4+)CD25high regulatory T cells (Treg) to confer suppression of myelin-specific immune responses. Whereas Treg frequencies were equally distributed in blood and cerebrospinal fluid of MS patients and did not differ compared to healthy controls, the suppressive potency of patient-derived (CD4+)CD25high T lymphocytes was impaired. Their inhibitory effect on antigen-specific T cell proliferation induced by human recombinant myelin oligodendrocyte protein as well as on immune responses elicited by polyclonal and allogeneic stimuli was significantly reduced compared to healthy individuals. The effect was persistent and not due to responder cell resistance or altered survival of Treg, suggesting that a defective immunoregulation of peripheral T cells mediated by (CD4+)CD25high T lymphocytes promotes CNS autoimmunity in MS.     

CD44和CD44v6基因在胃腺癌组织中的表达及其意义

目的： 研究胃腺癌组织中ＣＤ４４ 的表达及其与淋巴结转移和预后的关系。方法： 应用免疫组化方法, 对１０５ 例胃腺癌组织中ＣＤ４４ 的表达进行了观察, 并对其中６２ 例患者做了随访。结果： ＣＤ４４ 和ＣＤ４４ｖ６ 基因的表达率分别为５４－３ ％ 和４８－６ ％ 。ＣＤ４４ｖ６ 在胃腺癌组织中的表达与癌细胞的分化、浸润深度, 以及临床分期和预后有关（Ｐ＜ ０－０５）, 而ＣＤ４４ 的表达则与上述临床病理指标无关。另外, 抗ＣＤ４４ 和抗ＣＤ４４ｖ６ 抗体的阳性反应, 与癌细胞的淋巴结转移有关（ＣＤ４４ｖ６, Ｐ＜ ０－０１ ; ＣＤ４４ , Ｐ＜ ０－０５） 。结论： ＣＤ４４ 的表达可用于胃癌患者的病情监测, 其中ＣＤ４４ｖ６ 有望作为判断预后的一个指标。     

CD24,ALCAM在大肠癌的表达及其临床意义

目的:探讨CD24,ALCAM 在大肠癌中的表达及其与细胞增殖、血管生成的关系。方法:运用免疫组织化学检测66例大肠癌肿瘤组织CD24,ALCAM,CD34,PCNA 的表达情况,根据CD34 的染色情况计算出大肠癌组织的微血管密度（microvessel density, MVD）,根据PCNA染色情况计算出肿瘤细胞PCNA标记指数。结果：免疫组织化学染色显示正常大肠黏膜CD24,ALCAM 绝大部分呈阴性染色,超过75%的大肠癌细胞有不同程度的CD24 染色。44%的肿瘤CD24 呈中等强度表达,26%的肿瘤呈强阳性表达。 高Dukes分期、高pTNM分期及有淋巴结转移、浆膜外浸润的癌组织中CD24 蛋白染色强度显著高于对应组（P＜0.01)。68% 的大肠癌细胞有不同程度的ALCAM 染色。ALCAM 表达与浸润深度、pTNM分期,淋巴结转移明显正相关。在CD24,ALCAM 阳性表达病例中,PCNA 的表达随着CD24 表达强度的升高而升高（P＜0.05）。大肠癌CD24 蛋白表达强度与大肠癌微血管密度轻度相关（r=0.228,P=0.019）。大肠癌ALCAM 蛋白质表达与MVD无关（P=0.17）。结论：CD24,ALCAM 可能在大肠癌发生发展中起重要作用。     

E-cadherin、β-catenin、CD44v6在乳腺癌中的表达

目的　探讨乳腺癌中E cadherin(E cad)、β catenin(β cat)、CD4 4v6蛋白表达。 方法　采用免疫组化S P法测定 4 8例乳腺癌中E cad、β cat、CD4 4v6蛋白的表达。 结果　E cad、β cat蛋白的表达强度 ,无淋巴结转移组高于有淋巴结转移组 (P <0 0 5 ) ,与肿瘤的大小、病理分级、组织学分类无关 ;在乳腺癌中随着E cad强度的增加 ,β cat阳性率亦呈上升趋势 (P <0 0 5 )。CD4 4v6蛋白的表达强度 ,有淋巴结转移组高于无淋巴结转移组 (P <0 0 5 ) ,与肿瘤的大小、病理分级、组织学分类无关。结论　E cad、β cat、CD4 4v6的表达可作为判断乳腺癌是否转移的可靠指标     

胃良恶性病变组织中CD24和CD44v6的表达及其意义

目的： 研究胃良恶性病变组织中癌干细胞标记物CD24、CD44v6的表达并探讨其临床病理意义。方法: 49例胃癌、20例癌旁组织、36例淋巴结转移灶及80例不同类型胃良性病例（浅表性胃炎10例，萎缩性胃炎15例，胃溃疡20例，胃息肉20例，胃腺瘤15例）标本常规制作石蜡包埋切片，CD24和CD44v6染色方法为EnVision免疫组化法。结果: 胃癌病例CD24和CD44v6表达阳性率明显高于癌旁组织和不同类型胃良性病变（P＜0.05或P＜0.01），且阳性表达的良性病例胃黏膜上皮均呈中至重度不典型增生；转移灶CD24和CD44v6表达与相应原发灶呈现高度一致性（P>0.05）；组织学分级Ⅱ级、无淋巴结转移及无远处器官转移胃癌病例CD24和CD44v6表达阳性率明显低于组织学分级Ⅲ或Ⅳ级、淋巴结转移及远处器官转移病例（P＜0.05）。此外，浸润深度T₁-T₂及淋巴结N1站转移病例CD24表达阳性率明显低于浸润深度T₃-T₄和淋巴结N₂、N₃站转移病例（P＜0.05）。结论: CD24和CD44v6表达可能是反映胃癌发生、进展、生物学行为和预后的重要癌干细胞标记物，检测胃良性病例CD24和CD44v6表达水平对预防和早期发现胃癌可能有一定的临床价值。     

Expression profiling of microdissected matched prostate cancer samples reveals CD166/MEMD and CD24 as new prognostic markers for patient survival

In order to screen for differentially expressed genes that might be useful in diagnosis or therapy of prostate cancer we have used a custom made Affymetrix GeneChip containing 3950 cDNA fragments. Expression profiles were obtained from 42 matched pairs of mRNAs isolated from microdissected malignant and benign prostate tissues. Applying three different bioinformatic approaches to define differential gene expression, we found 277 differentially expressed genes, of which 98 were identified by all three methods. Fourteen per cent of these genes were not found in other expression studies, which were based on bulk tissue. Resultant candidate genes were further validated by quantitative RT-PCR, mRNA in situ hybridization and immunohistochemistry. AGR2 was over-expressed in 89% of prostate carcinomas, but did not have prognostic significance. Immunohistologically detected over-expression of MEMD and CD24 was identified in 86% and 38.5% of prostate carcinomas respectively, and both were predictive of PSA relapse. Combined marker analysis using MEMD and CD24 expression proved to be an independent prognostic factor (RR = 4.7, p = 0.006) in a Cox regression model, and was also superior to conventional markers. This combination of molecular markers thus appears to allow improved prediction of patient prognosis, but should be validated in larger studies.     

Irgm1基因敲除对实验性自身免疫性脑脊髓炎小鼠CD4~+ T细胞亚群的影响

目的:探讨免疫相关GTP酶1(Irgm1)基因敲除对实验性自身免疫性脑脊髓炎(Experimental autoimmune encephalomyelitis,EAE)小鼠CD4+T细胞的影响。方法:C57BL/6纯系小鼠与Irgm1基因敲除杂合小鼠(Irgm1+/-)回交十代繁殖C57BL/6背景下Irgm1+/-小鼠,用C57BL/6 Irgm1+/-小鼠杂交获取Irgm1-/-、Irgm1+/-、Irgm1+/+三种基因型小鼠,PCR扩增DNA检测基因型。用髓鞘少突胶质糖蛋白(Myelin oligodendrocyte glycoprotein,MOG33-55)多肽与弗氏完全佐剂等量混合制成乳剂,免疫C57BL/6野生型(Wt.)和Irgm1基因敲除(Irgm1-/-)小鼠,建立EAE模型,并进行临床评分。MTT法测定MOG33-55免疫后7 d的EAE小鼠淋巴结细胞中MOG33-55特异性T细胞增殖分化水平。取MOG33-55免疫后14 d EAE小鼠脊髓切片,HE染色检测炎细胞浸润情况。取MOG33-55免疫后16 d的EAE-小鼠淋巴结、脊髓和脑组织,提取单个核细胞,用MOG33-55(20μg/ml)体外刺激培养7 d,收集细胞,用流式细胞仪分析EAE小鼠淋巴结、中枢神经系统浸润细胞中Th1、Th17的改变。结果:成功诱导了EAE小鼠模型;HE染色结果显示Wt.小鼠脊髓周围出现明显炎细胞浸润,而Irgm1-/-小鼠则无明显变化;MTT实验表明Irgm1-/-小鼠与Wt.小鼠相比,淋巴结中T细胞对MOG33-55特异性增殖能力降低;流式细胞分析表明相对于Wt.小鼠,Irgm1-/-小鼠EAE模型在淋巴结及中枢神经系统浸润细胞中Th1细胞亚群比例明显增高而Th17细胞亚群比例下降。结论:Irgm1基因敲除可部分保护EAE小鼠的脊髓功能及临床症状。在EAE发病早期,Irgm1可能起到了关键性的作用,因此Irgm1有可能成为EAE治疗的重要分子靶点。     

乳腺癌中OPN、CD44v6及CD10的表达及其临床意义

目的探讨骨桥蛋白(osteopontin,OPN)、CD44v6、CD10在乳腺癌及腺病中的表达,分析三者与乳腺癌临床病理特征及预后的相关性。方法采用免疫组化En Vision两步法检测OPN、CD44v6、CD10在浸润性癌非特指型(153例)、导管原位癌(40例)、腺病(28例)中的表达;采用χ2检验分析三者与乳腺癌临床病理特征的关系,多因素分析采用Cox回归模型,预后分析采用Kaplan-Meier法,组间差异比较采用Log-rank检验。结果在腺病、导管原位癌、浸润性癌非特指型中,OPN阳性率分别为7.1%、27.5%、56.2%,CD44v6阳性率分别为10.7%、40.0%、57.5%,CD10阳性率分别为3.5%、37.5%、55.6%。三者在腺病中的阳性率均低于乳腺癌,差异具有统计学意义(P=0.020、0.042、0.003)。浸润性癌非特指型组织中OPN、CD44v6和CD10的表达均与组织学分级、淋巴结转移相关,且OPN、CD44v6表达均与p TNM分期相关,CD44v6表达与PR状态相关(P均0.05);在导管原位癌中三者的表达与核分级相关,差异均有统计学意义(P均0.05);三者的表达与患者年龄、绝经状态、脉管浸润、Ki-67增殖指数、ER状态、HER-2状态均无关(P均0.05)。OPN、CD44v6和CD10在乳腺癌中的表达两两间均呈正相关(P均0.001)。多因素分析提示淋巴结转移、CD10阳性是浸润性癌非特指型患者的预后影响因素。生存分析显示在浸润性癌非特指型中,三者均阴性组患者的无病生存率(disease-free survival,DFS)、总生存率(overall survival,OS)均优于三者均阳性组,差异有统计学意义(P=0.010、0.007)。结论 OPN、CD44v6、CD10在乳腺癌中高表达,均与乳腺癌进展相关。联合检测OPN、CD44v6、CD10在乳腺癌中的表达,对于判断患者预后具有重要价值。