Secreted MUC1 mucins lacking their cytoplasmic part and carrying sialyl-Lewis a and x epitopes from a tumor cell line and sera of colon carcinoma patients can inhibit HL-60 leukocyte adhesion to E-selectin-expressing endothelial cells

A secreted MUC1 mucin from the spent medium of the colon carcinoma cell line COLO 205 carrying sialyl-Lewis a and x epitopes (H-CanAg) was purified by trichloroacetic acid precipitation and Superose 6 gel filtration. The purified H-CanAg inhibited adhesion of the leukocyte cell line HL-60 to E-selectin transfected COS-1 cells or interleukin-1β (IL-1β)-activated human umbilical vein endothelial cells. Sera from two patients with advanced colon carcinoma containing high concentrations of sialyl-Lewis a and x activity inhibited HL-60 cell adhesion to E-selectin-expressing COS-1 cells and IL-1β-activated endothelial cells. After affinity column absorption of the sialyl-Lewis a activity, the sera also lost most of their sialyl-Lewis x activity and at the same time their adhesion inhibitory effect. A large part of the sialyl-Lewis a/x activity in the two patients was found in fractions containing mucins having a MUC1 apoprotein, as shown by its size, and reactivity with the two anti-MUC1 apoprotein monoclonal antibodies, Ma552 and HMFG-2. The cell-adhesion inhibitory effect of the purified sialyl-Lewis a-carrying MUC1 mucin fraction from the sera of the two patients was stronger than that of smaller sized sialyl-Lewis a-carrying mucin-type glycoproteins also found in the patient sera. The MUC1 mucin fraction secreted by the COLO 205 cells and from the two sera were all shown to lack their C-terminal portion, in contrast to the MUC1 mucin from cells. It is hypothesized that sialyl-Lewis a- and/or x-containing mucins, especially MUC1, secreted by tumors can interact with E-selectin on endothelial cells and thus inhibit leukocyte adhesion. © 1996 Wiley-Liss, Inc.     

Histochemical study on the bile duct system of normal Mongolian gerbils

The bile duct system of normal Mongolian gerbils was examined histochemically. The luminal surface membrane and apical cytoplasm of the biliary and gallbladder epithelial cells were stained with periodic acid-Schiff (PAS), alcian blue, pH 2.5 (AB) and high iron diamine (HID)-AB, and many epithelial cells of the common bile duct and gallbladder had weakly PAS-positive granular material in their supranuclear cytoplasm. Lectin-histochemically, these cells had binding sites to Concanavalia ensiformis (ConA), Dolichos biflorus (DBA), Glycine max (SBA), Ulex europeas-I (UEA-I), and Triticum vulgaris (WGA). On the other hand, the periductal glandular epithelial cells were not stained by any histochemical stainings. In addition to these light microscopic findings, the electron microscopic findings based on the periodic acid-silver methenamine method and avidin-biotin colloidal gold method for DBA and WGA suggested that the biliary and gallbladder epithelial cells of Mongolian gerbils secreted mucin with terminal sialic and sulfonic acid residues and that the lectin binding activity of mucin secreted from these cells was similar to that of mucin secreted from the periductal glandular epithelial cells of mice and rats.     

Human carcinoma-associated and salivary mucins detected by anti-bovine submaxillary mucin antibodies

Polyclonal rabbit anti-bovine submaxillary mucin antibodies, anti-BSM IgG, were analyzed by autoradiography and densitometry (after SDS electrophoresis and blotting), ELISA, and IRMA assays for reactivity against native antigen BSM, deglycosylated and desialylated BSM, and human salivary and carcinoma-associated mucins. Known human tumor marker CA19-9 antigen reacted with rabbit anti-BSM IgG under different conditions, either soluble or immobilized. As soluble antigen, in IRMA it reacted with anti-BSM antibodies used both as a catcher and a tracer, as well as in combination with monoclonal anti-CA19-9 antibodies as a catcher. MUC1 mucin is a carrier of this carbohydrate antigen, CA19-9, or sialyl-Lewis(a), as well as of CA15-3 antigen, a known breast tumor marker. Autoradiography and densitometry demonstrated binding of anti-BSM IgG to intact MUC1 in a sample of commercial standard preparation of CA19-9 antigen. The same method and analysis demonstrated binding of anti-BSM IgG to MUC1 and to smaller antigens of 85-120 kD in samples containing CA15-3 antigen: commercial standard preparation, human breast tissue, and human milk. In a sample of whole human saliva, reactions of both isoforms of MUC7 were detected by autoradiography, as bands of 85 and 115 kD, and densitogram analysis also demonstrated reaction with MUC5B. Chemical modifications performed as periodate oxidation and desialylation of the BSM demonstrated carbohydrate (i.e., sialic acid) epitope sensitivity for anti-BSM IgG. The results presented in this work indicate that polyclonal anti-BSM antibodies are specific for sialylated carbohydrate structure on mucins and could serve as a tool for investigation of human carcinoma-associated and salivary mucins.     

Cholestan-3beta,5alpha,6beta-triol, but not 7-ketocholesterol, suppresses taurocholate-induced mucin secretion by cultured dog gallbladder epithelial cells

In order to investigate oxysterol-mediated effects on the biliary system, we studied the effects of cholestan-3beta,5alpha,6beta-triol (TriolC) and 7-ketocholesterol (7KC) on gallbladder epithelial cells. We compared their cell proliferation effects in cultured dog gallbladder epithelial cells (DGBE) to their effects in cultured human pulmonary artery endothelial cells (HPAE). Oxysterols inhibited cell proliferation in a dose-dependent fashion. Oxysterols inhibited cell growth to 50% of control at a higher dose for DGBE cells than for HPAE cells. TriolC was more cytotoxic than 7KC. We also investigated the effect of oxysterols on bile salt-induced mucin secretion by DGBE cells. TriolC suppressed mucin secretion by DGBE cells, whereas 7KC did not. These findings support the hypothesis that biliary oxysterols affect gallbladder mucosal function.     

Species-Specific and Conserved Epitopes on Mouse and Human E-Selectin Important for Leukocyte Adhesion

Selectins are C-type, cell surface lectins that are key players in leukocyte adhesion to the blood vessel wall endothelium. We describe here epitopes for a series of novel monoclonal antibodies (moAbs), UZ4-UZ7, directed against mouse E-selectin. All four antibodies specifically bind to mouse E-selectin, but not to P- or L-selectin, and all inhibit the adhesion of granulocytes, peripheral blood lymphocytes, and promyelocytic HL-60 cells to cytokine-activated mouse endothelium. Three moAbs, UZ5, UZ7, and UZ6, specifically inhibit mouse E-selectin-mediated adhesion by binding to epitopes in domains CR1 or CR2. moAb UZ4 inhibits leukocyte adhesion to both human and murine endothelium activated with IL-1 or other proinflammatory stimuli. UZ4 is the first described moAb that detects an epitope in the lectin domain which is conserved in both murine and human E-selectin (CXKKKL), but is not present in the other members of the selectin family, P- and L-selectin. Interestingly, UZ5, UZ6, and UZ7 more efficiently interfere with lymphocyte than with granulocyte adhesion to cytokine-activated endothelium, while UZ4 completely blocks adhesion of PMN, lymphocytes, and HL-60 and U937 cell lines. The data suggest that E-selectin–ligand engagement differs between lymphocytes and PMN, and that these differences may be accentuated by the CR1 and CR2 domains in the E-selectin cell adhesion molecule.     

Tumor cell MUC1 and CD43 are glycosylated differently with sialyl-Lewis a and x epitopes and show variable interactions with E-selectin under physiological flow conditions

The mucins secreted from the colon carcinoma cell line COLO 205 have the MUC1 and CD43 (leukosialin) as core proteins, where both carry sialyl-Lewis a and MUC1 sialyl-Lewis x epitopes. The adhesion of E-selectin expressing CHO cells to the coated mucins was analyzed in a flow system revealing that the MUC1 mucin adhered better than the CD43 mucin. One reason could be their different glycosylation, a difference that was explored by analyzing the biosynthesis of MUC1 and CD43 in COLO 205 cells. Both the MUC1 and CD43 mucins became sialyl-Lewis a reactive, but after different times as revealed by pulse-chase studies. However, only MUC1 became sialyl-Lewis x reactive. These differences suggest that MUC1 and CD43 are synthesized in different compartments of the cell. It was also observed that the mucins from colon carcinoma patients had MUC1-type mucins that carried both sialyl-Lewis a and x epitopes and CD43-type sialyl-Lewis a mucins with only low levels of sialyl-Lewis x epitopes. One could hypothesize that colon carcinoma derived MUC1 is decorated with potent E-selectin epitopes, and that this could be one of several reasons for the involvement of MUC1 in cancer development.     

Mucin secretion by the human colon cell line LS174T is regulated by bile salts

We recently reported that bile salts play a role in the regulation of mucin secretion by cultured dog gallbladder epithelial cells. In this study we have examined whether bile salts also influence mucin secretion by the human epithelial colon cell line LS174T. Solutions of bile salts were applied to monolayers of LS174T cells. Mucin secretion was quantified by measuring the secretion of [3H]GlcNAc labeled glycoproteins. Both unconjugated bile salts as well as taurine conjugated bile salts stimulated mucin secretion by the colon cells in a dose-dependent fashion. Hydrophobic bile salts were more potent stimulators than hydrophilic bile salts. Free (unconjugated) bile salts were more stimulatory compared with their taurine conjugated counterparts. Stimulation of mucin secretion by LS174T cells was found to occur at much lower bile salt concentrations than in the experiments with the dog gallbladder epithelial cells. The protein kinase C activators PMA and PDB had no stimulatory effect on mucin secretion. We conclude that mucin secretion by the human colon epithelial cell line LS174T is regulated by bile salts. We suggest that regulation of mucin secretion by bile salts might be a common mechanism, by which different epithelia protect themselves against the detergent action of bile salts, to which they are exposed throughout the gastrointestinal tract.      

Diverse monoclonal antibodies against the CA 19-9 antigen show variation in binding specificity with consequences for clinical interpretation

The CA 19-9 antigen is currently the best individual marker for the detection of pancreatic cancer. In order to optimize the CA 19-9 assay and to develop approaches to further improve cancer detection, it is important to understand the specificity differences between CA 19-9 antibodies and the consequential affect on biomarker performance. Antibody arrays enabled multiplexed comparisons between five different CA 19-9 antibodies used in the analysis of plasma samples from pancreatic cancer patients and controls. Major differences were observed between antibodies in their detection of particular patient samples. Glycan array analysis revealed that certain antibodies were highly specific for the canonical CA 19-9 epitope, sialyl-Lewis A, while others bound sialyl-Lewis A in addition to a related structure called sialyl-Lewis C and modification with Nue5Gc. In a much larger patient cohort, we confirmed the binding of sialyl-Lewis C glycan by one of the antibodies and showed that the broader specificity led to the detection of an increased number of cancer patients without increasing detection of pancreatitis patient samples. This work demonstrates that variation between antibody specificity for cancer-associated glycans can have significant implications for biomarker performance and highlights the value of characterizing and detecting the range of glycan structures that are elevated in cancer.     

Human gallbladder mucin binds biliary lipids and promotes cholesterol crystal nucleation in model bile

The binding of phosphatidylcholine and cholesterol in model bile to human gallbladder mucin was studied by means of a rapid filtration binding assay and sucrose density gradient ultracentrifugation. Numerous low affinity binding sites for phosphatidylcholine and cholesterol were present on gallbladder mucin. Binding of phosphatidylcholine and cholesterol to mucin increased as a function of cholesterol saturation index. Proteolytic digestion of mucin disaggregated the native mucin polymer and removed hydrophobic domains on the mucin peptide core that bind l-anilino-8-naphthalenesulfonic acid. Proteolytic digestion also resulted in a 91% and 78% decrease, respectively, in the binding of phosphatidylcholine and cholesterol to mucin. The ability of trypsin-treated and native mucin to promote the nucleation of cholesterol monohydrate crystals was compared in a model bile. The incidence of cholesterol monohydrate crystal nucleation with native mucin was significantly greater at 3 days than with trypsin-treated mucin or controls (P less than 0.001). After 3, 6, and 9 days of incubation, samples containing native mucin contained significantly more crystals than controls or trypsin-digested mucin samples (P less than 0.0001 for each). These data indicate that highly purified human gallbladder mucin binds phosphatidylcholine and cholesterol in model bile. Furthermore, this study demonstrates that structural integrity of the native mucin polymer and hydrophobic domains on the peptide core are essential for the nucleation of cholesterol monohydrate crystals by mucin in model bile.     

Calcium binding to biliary mucins is dependent on sodium ion concentration: relevance to cystic fibrosis

Because hypersecretion of gallbladder (GB) mucus occurs in gallstone formation and because binding of Ca(2+) to biliary lipids only accounts for 50% of the total Ca(2+) in GB bile, we investigated the binding of Ca(2+) to human biliary mucin. Biliary mucin was purified from GB bile and binding to Ca(2+) studied. Scatchard plot analysis suggested two binding sites. Removal of sialic acid by neuraminidase resulted in 10% reduction of Ca(2+) binding, whereas, sulfatase treatment reduced Ca(2+) binding by 30%. Using a hypotonic NaCl solution, Ca(2+) binding to mucin increased curvilinearly with mucin concentration. However, binding decreased with increasing ionic strength of the NaCl solution. We conclude that binding of Ca(2+) to mucin is effected mainly through sulfate. Binding to Ca(2+) can be displaced by Na(+). Ca(2+) binding to mucins is enhanced in the setting of low Na(+) concentrations. This phenomenon has pathophysiologic implications for the formation of thick mucus in cystic fibrosis epithelia.     

Human carcinoma-associated and salivary mucins detected by anti-bovine submaxillary mucin antibodies

Polyclonal rabbit anti-bovine submaxillary mucin antibodies, anti-BSM IgG, were analyzed by autoradiography and densitometry (after SDS electrophoresis and blotting), ELISA, and IRMA assays for reactivity against native antigen BSM, deglycosylated and desialylated BSM, and human salivary and carcinoma-associated mucins. Known human tumor marker CA19-9 antigen reacted with rabbit anti-BSM IgG under different conditions, either soluble or immobilized. As soluble antigen, in IRMA it reacted with anti-BSM antibodies used both as a catcher and a tracer, as well as in combination with monoclonal anti-CA19-9 antibodies as a catcher. MUC1 mucin is a carrier of this carbohydrate antigen, CA19-9, or sialyl-Lewis^a, as well as of CA15-3 antigen, a known breast tumor marker. Autoradiography and densitometry demonstrated binding of anti-BSM IgG to intact MUC1 in a sample of commercial standard preparation of CA19-9 antigen. The same method and analysis demonstrated binding of anti-BSM IgG to MUC1 and to smaller antigens of 85–120 kD in samples containing CA15-3 antigen: commercial standard preparation, human breast tissue, and human milk. In a sample of whole human saliva, reactions of both isoforms of MUC7 were detected by autoradiography, as bands of 85 and 115 kD, and densitogram analysis also demonstrated reaction with MUC5B. Chemical modifications performed as periodate oxidation and desialylation of the BSM demonstrated carbohydrate (i.e., sialic acid) epitope sensitivity for anti-BSM IgG. The results presented in this work indicate that polyclonal anti-BSM antibodies are specific for sialylated carbohydrate structure on mucins and could serve as a tool for investigation of human carcinoma-associated and salivary mucins.     

Soluble E-Selectin Enhances Intercellular Adhesion Molecule-1 (ICAM-1) Expression in Human Tumor Cell Lines

E-selectin mediates neovascularization via its soluble form, while its membrane-bound form initiates binding of tumor cells to vascular endothelium. Therefore, it was studied whether soluble E-selectin regulates further adhesion molecules on tumor cells. In tumor cells but not in related nonmalignant cells, intercellular adhesion molecule (ICAM)-1 expression was strikingly increased from 5 to 68% positive cells byin vitroinoculation of a recombinant E-selectin–IgG1 within 24 h, as analyzed by flow cytometry. The absence of changes in the expression of vascular cell adhesion molecule, integrin ligands (CD11a, CD18, integrin α4), and sialyl-Lewis X indicates a specific effect of soluble E-selectin on ICAM-1. A cell adhesion assay revealed that the enhanced adhesion of T-cells to tumor cells mediated by soluble E-selectin-induced ICAM-1 expression was at a maximum after a 12-h incubation period. Therefore, ICAM-1 regulation on tumor cells might be a mechanism of immune escape.     

Expression profiles of MUC mucins and trefoil factor family (TFF) peptides in the intrahepatic biliary system: physiological distribution and pathological significance

Mucin secreted by mucosal epithelial cells plays a role in the protection of the mucosal surface and also is involved in pathological processes. So far, MUC1-4, 5AC, 5B, 6-8, 11-13 and 15-17 genes coding the backbone mucin core protein have been identified in humans. Their diverse physiological distribution and pathological alterations have been reported. Trefoil factor family (TFF) peptides are mucin-associated molecules co-expressed with MUC mucins and involved in the maintenance of mucosal barrier and the biological behavior of epithelial and carcinoma cells. Intrahepatic biliary system is a route linking the bile canaliculi and the extrahepatic bile duct for the excretion of bile synthesized by hepatocytes. Biliary epithelial cells line in the intrahepatic biliary system, secreting mucin and other molecules involved in the maintenance and regulation of the system. In this review, the latest information regarding properties, expression profiles and regulation of MUC mucins and TFF peptides in the intrahepatic biliary system is summarized. In particular, we focus on the expression profiles and their significance of MUC mucins in developmental and normal livers, various hepatobiliary diseases and intrahepatic cholangiocarcinoma.     

alpha(1,2)-fucosylation prevents sialyl Lewis x expression and E-selectin-mediated adhesion of fucosyltransferase VII-transfected cells.

E-selectin is a cytokine-inducible, calcium-dependent endothelial cell adhesion molecule that plays a critical role in the leucocyte-endothelium interaction during inflammation and is thought to contribute to the metastatic dissemination of tumour cells. Like the other selectins, E-selectin binds to ligands carrying the tetrasaccharide sialyl-Lewis x (NeuAcalpha2,3Galbeta1,4[Fucalpha1, 3]GlcNAc)1 or its isomer sialyl-Lewis a (NeuAcalpha2, 3Galbeta1, 3[Fucalpha1,4]GlcNAc). We examined the effect of expressing the H-type alpha(1,2)-fucosyltransferase or the alpha(2, 6)-sialyltransferase on the synthesis of sialyl-Lewis x by alpha(1, 3)fucosyltransferase. We found that H-type alpha(1, 2)-fucosyltransferase but not alpha(2,6)-sialyltransferase, strongly inhibited sialyl-Lewis x expression and E-selectin adhesion. We assume that H-type alpha(1,2)-fucosyltransferase competes with the endogenous alpha(2,3)-sialyltransferase for the N-acetyllactosamine structures assigned to further serve as acceptors for alpha(1, 3)fucosyltransferase.     

Recombinant E-selectin-protein mediates tumor cell adhesion via sialyl-Le(a) and sialyl-Le(x).

E-selectin (previously known as ELAM-1) is one of the adhesion molecules expressed on activated endothelium. Here we show that HL-60 cells express sialyl-Le(x), but not Sialyl-Le(a) on their surface, a colon carcinoma cell line COLO 205 express both these epitopes and another colon carcinoma COLO 320 does not express either one of them. HL-60 and COLO 205 cell adhere strongly to E-selectin coated microwells, whereas COLO 320 does not adhere at all to E-selectin. Finally we provide evidence that monoclonal anti-sialyl-Le(x) can abolish part of the adherence of HL-60 cells to recombinant E-selectin. The adherence of COLO 205 cells can be decreased by either monoclonal anti-sialyl-Le(a) or anti-sialyl-Le(x) antibodies. These results indicate that cell-associated sialylated carbohydrate moieties can act as ligands for recombinant E-selectin.     

No pathophysiologic relationship of soluble biliary proteins to cholesterol crystallization in human bile

This study explores the pathophysiologic effects of soluble biliary glycoproteins in comparison to mucin gel and cholesterol content on microscopic crystal and liquid crystal detection times as well as crystallization sequences in lithogenic human biles incubated at 37 degrees C. Gallbladder biles from 13 cholesterol gallstone patients were ultracentrifuged and microfiltered (samples I). Total biliary lipids were extracted from portions of samples I, and reconstituted with 0.15 m NaCl (pH 7.0) (samples II). Portions of samples II were supplemented with purified concanavalin A-binding biliary glycoproteins (final concentration = 1 mg/mL) (samples III), or mucin gel (samples IV), respectively, isolated from the same cholesterol gallstone biles. Samples V consisted of extracted biliary lipids from uncentrifuged and unfiltered bile samples reconstituted with 0.15 m NaCl (pH 7.0). Analytic lipid compositions of samples I through IV were identical for individual biles but, as anticipated, samples V displayed significantly higher cholesterol saturation indexes. Detection times of cholesterol crystals and liquid crystals were accelerated in the rank order of samples: IV > V > I = II = III, indicating that total soluble biliary glycoproteins in pathophysiologic concentration had no appreciable effect. Crystallization sequences (D. Q-H. Wang and M. C. Carey. J. Lipid Res. 1996. 37: 606-630; and 2539-2549) were similar among samples I through V. Crystal detection times and numbers of solid cholesterol crystals were accelerated in proportion to added mucin gel and the cholesterol saturation of bile only.For pathophysiologically relevant conditions, our results clarify that mucin gel and cholesterol content, but not soluble biliary glycoproteins, promote cholesterol crystallization in human gallbladder bile.     

A novel role for interleukin-18 in adhesion molecule induction through NF kappa B and phosphatidylinositol (PI) 3-kinase-dependent signal transduction pathways

Interleukin-18 (IL-18) is a novel proinflammatory cytokine found in serum and joints of patients with rheumatoid arthritis (RA). We studied a novel role for IL-18 in mediating cell adhesion, a vital component of the inflammation found in RA and other inflammatory diseases. We examined the expression of cellular cell adhesion molecules E-selectin, vascular cell adhesion molecule-1 (VCAM-1), and intercellular adhesion molecule-1 (ICAM-1) on endothelial cells and RA synovial fibroblasts using flow cytometry. Adhesion of the monocyte-like cell line HL-60 to endothelial cells was determined by immunofluorescence. IL-18 significantly enhanced ICAM-1 and VCAM-1 expression on endothelial cells and RA synovial fibroblasts. In addition, IL-18 induced E-selectin expression on endothelial cells and promoted the adhesion of HL-60 cells to IL-18-stimulated endothelial cells. Neutralizing anti-VCAM-1 and anti-E-selectin could completely inhibit HL-60 adherence to endothelial cells. IL-18-induced adhesion molecule expression appears to be mediated through nuclear factor kappa B (NF kappa B) and phosphatidyl-inositol 3 kinase (PI 3-kinase) since addition of inhibitors to either NF kappa B (pyrrolidine dithiocarbamate and N-acetyl-l-cysteine) or PI 3-kinase (LY294002) inhibited RA synovial fibroblast VCAM-1 expression by 50 to 60%. Addition of both inhibitors resulted in inhibition of VCAM-1 expression by 85%. In conclusion, the ability of IL-18 to induce adhesion molecule expression on endothelial cells and RA synovial fibroblasts indicates that IL-18 may contribute to RA joint inflammation by enhancing the recruitment of leukocytes into the joint. IL-18 requires NF kappa B as well as PI 3-kinase to induce VCAM-1 on RA synovial fibroblasts, suggesting that there may be two distinct pathways in IL-18-induced adhesion molecule expression.     

血清肿瘤标志物联合多层螺旋CT和核磁共振对胆管癌的诊断价值及其与组织侵袭分子的关系分析

目的:探讨血清癌抗原19-9(CA19-9)、糖类抗原125(CA125)、多层螺旋CT和核磁共振(MRI)联合检测对胆管癌的诊断价值,并分析肿瘤标志物与组织侵袭分子的相关性。方法:选择2017年1月至2018年8月赤峰学院附属医院收治的胆管癌患者62例作为胆管癌组,另选择同期我院收治的胆管良性病变患者55例作为胆管良性病变组。比较两组血清CA19-9、CA125水平以及组织侵袭分子含量,观察胆管癌患者和胆管良性病变患者的多层螺旋CT和MRI影像学征象,分析血清CA19-9、CA125、多层螺旋CT和MRI对胆管癌的诊断价值,并分析血清CA19-9、CA125水平与组织侵袭分子含量的相关性。结果:胆管癌组血清CA19-9、CA125水平高于胆总管良性病变组,胆管癌组织赖氨酰氧化酶样蛋白-2(LOXL2)、瞬时受体电位阳离子通道7(TRPM7)含量高于胆总管良性病变组,组织E钙黏素(E-cadherin)含量低于胆总管良性病变组(P0.05)。多层螺旋CT影像学征象:胆管癌可见胆总管、肝管内圆形或类圆形高密度影伴有管壁浸润,胆管内出现不规则结节,肿块与周围组织界限模糊,胆囊管及胆囊颈部浸润,肝叶萎缩,淋巴结肿大等;胆管良性病变则多为圆形或类圆形高密度影,管壁浸润、淋巴结肿大并不多见。MRI影像学征象:胆管癌肝内胆管与肝组织分界不清,肿块呈不规则或分叶状,胆囊增大,肝内外胆管不同程度扩张,胰管扩张,肝叶萎缩,淋巴结肿大;胆管良性病变胆管则多为"杯口状"低信号充盈缺损,胆管梗阻上方出现"鸟嘴样"改变等。血清CA19-9、CA125、多层螺旋CT和MRI联合检测对胆管癌诊断的灵敏度、特异度、准确度均高于CA19-9、CA 125、多层螺旋CT、MRI单独诊断。胆管癌患者血清CA19-9、CA125水平与组织LOXL2、TRPM7含量呈正相关,与组织E-cadherin含量呈负相关(P0.05)。结论:血清CA19-9、CA125、多层螺旋CT和MRI联合检测对胆管癌诊断具有较好的价值,患者血清CA19-9、CA125水平与组织侵袭分子存在相关性,可以为胆管癌恶性程度的评估提供依据。     

Identification of Thioaptamer Ligand against E-Selectin: Potential Application for Inflamed Vasculature Targeting

Active targeting of a drug carrier to a specific target site is crucial to provide a safe and efficient delivery of therapeutics and imaging contrast agents. E-selectin expression is induced on the endothelial cell surface of vessels in response to inflammatory stimuli but is absent in the normal vessels. Thus, E-selectin is an attractive molecular target, and high affinity ligands for E-selectin could be powerful tools for the delivery of therapeutics and/or imaging agents to inflamed vessels. In this study, we identified a thiophosphate modified aptamer (thioaptamer, TA) against E-selectin (ESTA-1) by employing a two-step selection strategy: a recombinant protein-based TA binding selection from a combinatorial library followed by a cell-based TA binding selection using E-selectin expressing human microvascular endothelial cells. ESTA-1 selectively bound to E-selectin with nanomolar binding affinity (K_D = 47 nM) while exhibiting minimal cross reactivity to P- and L-selectin. Furthermore, ESTA-1 binding to E-selectin on the endothelial cells markedly antagonized the adhesion (over 75% inhibition) of sLe^x positive HL-60 cells at nanomolar concentration. ESTA-1 also bound specifically to the inflamed tumor-associated vasculature of human carcinomas derived from breast, ovarian, and skin but not to normal organs, and this binding was highly associated with the E-selectin expression level. Similarly, intravenously injected ESTA-1 demonstrated distinct binding to the tumor vasculature in a breast cancer xenograft model. Together, our data substantiates the discovery of a thioaptamer (ESTA-1) that binds to E-selectin with high affinity and specificity, thereby highlighting the potential application of ESTA-1 for E-selectin targeted delivery.