CD44 in hematological neoplasias

The CD44 protein family spans a large group of transmembrane glycoproteins acquired by alternative splicing and post-translational modifications. The great heterogeneity in molecular structure is reflected in its various important functions: CD44 mediates (1) interaction between cell and extracellular matrix, (2) signal submission, e.g., by acting as co-receptor for membrane-spanning receptor tyrosine kinases or by association with intracellular molecules initiating several signaling pathways, and (3) anchor function connecting to the cytoskeleton via the ezrin-radixin-moesin protein family. The expression pattern of the different CD44 isoforms display strong variations dependent on cell type, state of activation, and differentiation stage. In hematopoietic cells, CD44 mediates interaction of progenitor cells and bone marrow stroma during hematopoiesis, regulates maturation, and activation-induced cell death in T cells, influences neutrophil and macrophage migration as well as cytokine production, and participates in lymphocyte extravasation and migration. CD44 is involved in development and progress of hematological neoplasias by enhancement of apoptotic resistance, invasiveness, as well as regulation of bone marrow homing, and mobilization of leukemia-initiating cells into the peripheral blood. Thereby altered CD44 expression functions as marker for worse prognosis in most hematological malignancies. Additionally, CD44 expression levels can be used to distinguish between different hematological neoplasias and subtypes. Concerning new treatment strategies, CD44 displays promising potential either by direct targeting of CD44 expressed on the malignant cells or reversing an acquired resistance to primary treatment mediated through altered CD44 expression. The former can be achieved by antibody or hyaluronan-based immunotherapy.     

CD44与大肠癌

CD44与大肠癌@田慧军$武汉大学人民医院消化内科!武汉430060~~     

CD44V6和CD44S表达与膀胱癌转移的相关性研究

采用免疫组化ＳＡＢＣ法对８１例膀胱移行细胞癌患者癌组织中细胞粘附分子ＣＤ４４ｖ６和ＣＤ４４ｓ的表达进行检测。结果显示，ＣＤ４４ｖ６的阳性表达与膀胱癌临床分期、病理分级有显著关系，伴淋巴结转移组的ＣＤ４４ｖ６阳性表达率显著低于未转移组。     

CD44 is a phagocytic receptor

CD44, a transmembrane adhesion molecule involved in binding and metabolism of hyaluronan, has additional functions in inflammatory and immune responses, contributing to the ingestion and clearance of particles and apoptotic cells. Our goal was to determine the specific role of CD44 in phagocytosis and whether it functions as a primary or accessory phagocytic receptor. Using hyaluronan-coated beads and erythrocytes coated with antiCD44 antibodies as the phagocytic prey, we determined that CD44 mediates efficient phagocytosis in primary murine peritoneal macrophages and in the murine macrophage cell line RAW 264.7. In RAW cells, the phagocytic index for anti-CD44-coated erythrocytes was 25 +/- 3 (mean +/- SEM) compared with less than 1 for erythrocytes coated with isotype-matched control antibodies. Uptake of anti-CD44-coated erythrocytes was abrogated by pretreatment with a blocking antibody to CD44 and was absent in primary cultures of CD44-deficient murine macrophages. Down-regulation of Fc receptors by aggregated IgG-induced internalization, which blocks uptake of IgG-coated particles, had no effect on CD44-mediated particle engulfment. Using a combination of immunoprecipitation, pharmacologic inhibition, and genetic deletion, we determined that CD44-mediated phagocytosis involves Syk, Rac1, and phosphatidylinositol 3-kinase and induced activation of the phagocyte oxidase. We conclude that CD44 is a competent phagocytic receptor that efficiently mediates internalization of large particles.     

CD44v17在胃癌组织中的表达及其与临床生物学特性之间的关系

目的 探讨一种新的CD44变异体（CD44v17）在胃癌组织中的表达及其与临床生物学特性之间的关系.方法根据本实验室在MCF-7／Adr中新发现的1种CD44剪切拼接变异体CD44v17设计特异性引物,应用SYBR Green I荧光染料,采用实时PCR法检测87例胃癌组织及相应癌旁组织CD44v17 Mrna的表达,根据标准曲线计算CD44v17mRNA的表达量,分析CD44v17mRNA表达与胃癌临床生物学特性之间的关系.结果胃癌组织CD44v17 Mrna表达明显高于相应癌旁正常组织（P〈0.05）;肿瘤〉5 cm组CD44v17 Mrna表达与肿瘤≤5 cm组表达比较差异无显著性（P〉0.05）;未分化腺癌组表达明显高于乳头状腺癌及管状腺癌组（P〈0.05）,乳头状腺癌组CD44v17 Mrna表达与管状腺癌组比较差异无显著性（P〉0.05）;肿瘤累及浆膜及浆膜外组CD44v17 Mrna表达显著高于侵及黏膜、黏膜下层及肌层组（P〈0.05）,而肿瘤侵及黏膜及黏膜下层组的CD44v17 Mrna表达与侵犯肌层组表达比较差异无显著性（P〉0.05）.淋巴结转移组CD44v17 Mrna表达明显高于淋巴结无转移组（P〈0.05）;有肝脏转移组CD44v17 Mrna表达显著高于无肝脏转移组（P〈0.05）.结论CD44v17 Mrna在胃癌组织中高表达,可能与胃癌的侵袭、转移及预后有关.     

CD44-specific antibody treatment and CD44 deficiency exert distinct effects on leukocyte recruitment in experimental arthritis

CD44, the leukocyte adhesion receptor for hyaluronan, has been considered a therapeutic target on the basis of the robust anti-inflammatory effect of CD44-specific antibodies in animal models of immune-mediated diseases. However, CD44 deficiency does not provide substantial protection against inflammation. Using intravital video microscopy in a murine model of rheumatoid arthritis, we show that CD44 deficiency and anti-CD44 antibody treatment exert disparate effects on leukocyte recruitment in inflamed joints. Leukocyte rolling, which is increased in CD44-deficient mice, is promptly abrogated in anti-CD44-treated wild-type mice. CD44-specific antibodies also trigger platelet deposition on granulocytes and subsequent depletion of this leukocyte subset in the circulation. These in vivo effects require CD44 cross-linking and are reproducible with an antibody against Gr-1, a molecule that, like CD44, is highly expressed on granulocytes. Anticoagulant pretreatment, which prevents platelet deposition, mitigates both granulocyte depletion and the suppressive effect of CD44-specific antibody on joint swelling. Our observations suggest that cross-linking of prominent cell surface molecules, such as CD44 or Gr-1, can initiate a rapid self-elimination program in granulocytes through engagement of the coagulation system. We conclude that the robust anti-inflammatory effect of CD44-specific antibodies in arthritis is primarily the result of their ability to trigger granulocyte depletion.     

Expression and clinical significance of CD44V5 and CD44V6 in resectable colorectal cancer

Purpose This study was conducted to evaluate the prognostic significance of CD44v5 and CD44v6 in resectable colorectal cancer.Materials and methods Membranous CD44v5 and CD44v6 levels were measured by an immunoenzymatic assay in tumors and surrounding mucosal samples obtained from 105 patients with resectable colorectal carcinomas.Results There were no significant differences of CD44v5 levels between tumors [median: 3.2 (range: 0.9–83.5) ng/mg protein) and surrounding mucosal samples (3 (3–146.2) ng/mg protein]. However, tumor samples showed significantly higher CD44v6 levels [19.5 (2.2–562.9) ng/mg protein] than mucosal samples [5 (5–230) ng/mg protein] (P=0.0001). Patients with higher CD44v5 or CD44v6 content in tumor samples had a considerably shorter relapse-free survival (P<0.05, for both). Patients with a higher CD44v6 content also had a shorter relapse-free and overall survival in the multivariate analysis (P<0.05).Conclusion The results of this study suggest a role of CD44v5 and CD44v6 in colorectal cancer progression. Membranous CD44v levels in primary tumors, measured by immunoenzymatic assay, may contribute to a more precise prognostic estimation in patients with resectable colorectal cancer.Supported by grants from ISCIII Red de Centros de Cancer RTICCC (C03/10) and Obra Social Cajastur     

Up-regulation of CD44 in rheumatoid chondrocytes

The adhesion molecule CD44 is thought to play an important role in the inflammatory process. To identify the expression of CD44 in articular chondrocytes in rheumatoid arthritis (RA), monoclonal anti-CD44 antibodies were immunohistochemically used to react with articular cartilage specimens of 15 patients with RA, 9 with osteoarthritis (OA), and 6 with femoral neck fracture (FF). The proportion of CD44-positive chondrocytes in RA was 93 +/- 2% (N=16), which was significantly higher than that in OA (59 +/- 7%, N=9, p<0.001) and FF (46 +/- 5%, N=6, p<0.001). Among CD44 isoforms examined, the hemopoietic form was dominant in chondrocytes in RA. Therefore, up-regulation of CD44 on chondrocytes may play a significant role in cartilage degeneration in RA.     

Expression of CD44 variants in osteosarcoma

The standard form of CD44 (CD44H) is a transmembranous glycoprotein, widely distributed on a variety of human lymphoid cells, epithelial cells and tumours. CD44 has many variant forms, which are generated by alternative splicing. In recent years, CD44 has been reported to be related to the degree of tumour differentiation, tumour cell invasion, and metastasis. We investigated 44 tumour specimens in 39 patients with osteosarcoma immunochemically to analyse the expression of CD44 standard (CD44H) and variant exon-encoded gene products (CD44v3, v4, v5, v6, v7, v9, and v10). Furthermore, the relationship between CD44 expression and the clinical outcome of patients with osteosarcoma was analysed. Membrane accentuation and exclusive cytoplasmic reactivity were analysed as separate staining patterns. Tumour cells and some multinucleated giant cells were markedly stained. CD44H, v3, v4, v5, v6, v7, v9, and v10 were expressed in 85%, 49%, 54%, 59%, 46%, 5%, 28%, and 10% of the specimens respectively. The cumulative 5-year metastasis-free survival was 58% in CD44v6-negative cases and 24% in CD44v6-positive cases (P=0.046). However, the cumulative 5-year metastasis-free survival was not significantly different between cases positive and negative for other variants of CD44. Multivariate analysis (Cox proportional-hazard model) with CD44v6 expression (positive or negative), chemotherapy (intensive or non-intensive), tumour site (proximal or distal), and age (at least 30 years or less than 30 years) showed that expression of CD44v6 and chemotherapy were important prognostic factors in patients with osteosarcoma. Overexpression of CD44 isoforms containing variant v6 is correlated with poor prognosis in patients with osteosarcoma. Received: 4 March 1999 / Accepted: 7 June 1999     

CD44V3、CD44V6和Ki-67在乳腺癌组织中的表达及意义

目的 探讨乳腺癌组织中CD44V3、CD44V6和Ki-67的表达及其与乳腺癌生物学行为的关系.方法 采用组织芯片技术结合免疫组化法检测60例乳腺浸润性导管癌和20例正常乳腺组织中的CD44V3、CD44V6和Ki-67的表达,并分析其与临床病理参数的关系.结果 乳腺癌组织中CD44V3、CD44V6和Ki-67的阳性表达率分别为41.7%、58.3%和68.3%,明显高于正常乳腺组织(P均＜0.05).乳腺癌组织中CD44V6和Ki-67的表达与乳腺癌组织病理分级、淋巴结转移有关(P＜0.05),同时CD44V6的表达与肿瘤的远处转移与否也有关(P＜0.05).乳腺癌组织中CD44V6与Ki-67的表达成正相关(r=0.587,P＜0.01).结论 CD44V6和Ki-67与乳腺癌的恶性生物学行为密切相关,可作为预测乳腺癌转移潜能的指标.     

CD8+CD44(hi) but not CD4+CD44(hi) memory T cells mediate potent graft antilymphoma activity without GVHD

Allogeneic hematopoietic cell transplantation can be curative in patients with leukemia and lymphoma. However, progressive growth of malignant cells, relapse after transplantation, and graft-versus-host disease (GVHD) remain important problems. The goal of the current murine study was to select a freshly isolated donor T-cell subset for infusion that separates antilymphoma activity from GVHD, and to determine whether the selected subset could effectively prevent or treat progressive growth of a naturally occurring B-cell lymphoma (BCL(1)) without GVHD after recipients were given T cell-depleted bone marrow transplantations from major histocompatibility complex-mismatched donors. Lethal GVHD was observed when total T cells, naive CD4(+) T cells, or naive CD8(+) T cells were used. Memory CD4(+)CD44(hi) and CD8(+)CD44(hi) T cells containing both central and effector memory cells did not induce lethal GVHD, but only memory CD8(+) T cells had potent antilymphoma activity and promoted complete chimerism. Infusion of CD8(+) memory T cells after transplantation was able to eradicate the BCL(1) lymphoma even after progressive growth without inducing severe GVHD. In conclusion, the memory CD8(+) T-cell subset separated graft antilymphoma activity from GVHD more effectively than naive T cells, memory CD4(+) T cells, or memory total T cells.     

CD44 (Pgp-1) inhibits CD3 and dexamethasone-induced apoptosis

Anti-CD3 monoclonal antibodies (MoAbs) and glucocorticoid hormones (GCH) induce apoptosis in immature thymocytes and peripheral T lymphocytes. This process is inhibited by a number of growth factors, including interleukin-2 (IL-2), IL-3, and IL-4, indicating that signals generated by membrane receptors can modulate the survival of lymphoid cells. To investigate whether signals activated by adhesion receptors have a similar activity, we analyzed the effect of CD44 (Pgp-1) adhesion molecule receptor stimulation on T-cell apoptosis induced by three stimuli (anti-CD3 MoAbs, dexamethasone [DEX] treatment, and exposure to ultraviolet irradiation [UV]) on a 3DO T-cell line. The results show that CD44 engagement, either by hyaluronic acid (HA) or anti-CD44 MoAbs, inhibits DNA fragmentation and apoptosis induced by DEX and anti-CD3 MoAbs, whereas that induced by UV, a p53-dependent phenomenon, was not inhibited. Furthermore, the antiapoptotic effect exerted through CD44 activation does not seem related to overexpression of bcl-2 or to have appreciable effects on cell proliferation. Our results indicate that adhesion molecules modulate T-cell survival by counteracting apoptosis induced by DEX or anti-CD3 MoAbs.     

Identification of CD44+CD24+ gastric cancer stem cells

Objective  

Purification and characterization of cancer stem cells (CSCs) can lead to the identification of targets for therapeutic interventions of cancer. With regard to gastric cancer, studies have not yet defined and characterized CSCs.     

Expression of CD44 variant isoforms CD44v3 and CD44v6 is increased on T cells from patients with systemic lupus erythematosus and is correlated with disease activity

Objective

To quantify the expression of CD44 and variant isoforms CD44v3 and CD44v6 on T cells from patients with systemic lupus erythematosus (SLE), and to assess correlations of the level of expression of these molecules with disease manifestations.

Methods

Information on clinical and demographic characteristics was collected, and blood samples were obtained from 72 patients with SLE and 32 healthy control subjects matched to the patients by sex, race, and age. Expression of CD44 and variants CD44v3 and v6 on T cell subsets was determined by flow cytometry, and Pearson's correlations of their expression levels with clinical variables, SLE Disease Activity Index (SLEDAI) scores, and presence of lupus nephritis were determined. Wilcoxon's rank sum tests and conditional multivariable regression analyses were applied to identify differences in the expression of CD44 between patients with SLE and healthy controls.

Results

Expression of CD44 was higher on CD4+ and CD8+ T cells from SLE patients compared with controls (P ≤ 0.03). Expression of CD44v3 and CD44v6 was also higher on total T cells and CD4+ and CD8+ T cells from SLE patients compared with controls (P ≤ 0.03). Cell surface levels of CD44v3 on total T cells, CD4+ T cells, and CD8+ T cells as well as cell surface expression of CD44v6 on total T cells and CD4+ T cells were correlated with the SLEDAI score (P < 0.05). The presence of lupus nephritis was associated with the expression of CD44v6 on total T cells, CD4+ T cells, and CD4−CD8− T cells (P < 0.05). Positivity for anti–double‐stranded DNA antibodies was associated with the expression levels of CD44v6 on T cells (P < 0.05).

Conclusion

These results indicate that expression levels of CD44v3 and CD44v6 on T cells may represent useful biomarkers of SLE activity.

     

Low serum levels of CD44, CD44v6, and neopterin indicate immune dysfunction in chronic pancreatitis

INTRODUCTION: In autoimmune diseases, malignancies, and inflammatory conditions, a correlation of serum levels of CD44, interleukin-2 receptor (IL-2r), and neopterin with disease activity could be shown. AIMS: To assess the immune parameters in chronic pancreatitis in correlation to clinical data to evaluate the potential role of immune dysfunction as a risk factor. METHODOLOGY: Levels of IL-2r, sCD44, sCD44v6, and neopterin were measured using the enzyme-linked immunosorbent assay in 63 patients with chronic pancreatitis who underwent surgery between 1992 and 1995 in our institution. Clinical data were evaluated prospectively before surgery, and a follow-up investigation was conducted in 1997. RESULTS: Mean serum levels of CD44, CD44v6, and neopterin were significantly lower in patients with chronic pancreatitis compared with the control group. The mean level of IL-2r was also lower in chronic pancreatitis, but this difference was not significant. However, no influence of immunosuppressive factors such as alcohol consumption, cigarette smoking, or diabetes could be detected on the levels of IL-2r, CD44, CD44v6, and neopterin. CONCLUSION: In accordance with other diseases of reduced immunoreactivity, depressed serum levels of biomarkers in chronic pancreatitis are caused by reduced T-lymphocyte and macrophage activation. By ruling out a significant influence of concomitant immunosuppressive factors, we conclude that the inflammatory process itself is the source of the depressed immune function, which might be restored by surgical resection.     

Expression and significance of CD44s, CD44v6, and nm23 mRNA in human cancer

AIM: To investigate the relationship between the expression levels of nm23 mRNA, CD44s, and CD44v6,and oncogenesis, development and metastasis of human gastric adenocarcinoma, colorectal adenocarcinoma,intraductal carcinoma of breast, and lung cancer.METHODS: Using tissue microarray by immuhistochemical (IHC) staining and in situ hybri-dization (ISH), we examined the expression levels of nm23mRNA, CD44s, and CD44v6 in 62 specimens of human gastric adenocarcinoma and 62 specimens of colorectal adenocarcinoma; the expression of CD44s and CD44v6in 120 specimens of intraductal carcinoma of breast and 20 specimens of normal breast tissue; the expression of nm23 mRNA in 72 specimens of human lung cancer and 23 specimens of normal tissue adjacent to cancer.RESULTS: The expression of nm23 mRNA in the tissues of gastric and colorectal adenocarcinoma was not significantly different from that in the normal tissues adjacent to cancer (P＞0.05), and was not associated with the invasion of tumor and the pathology grade of adenocarcinoma (P＞0.05). However, the expression of nm23 mRNA was correlated negatively to the lymph node metastasis of gastric and colorectal adenocarcinoma (r = -0.49, P＜0.01; r = -4.93, P＜0.01). The expression of CD44s in the tissues of gastric and colorectal adenocarcinoma was significantly different from that in the normal tissues adjacent to cancer (P＜0.05;P＜0.01). CD44v6 was expressed in the tissues of gastric and colorectal adenocarcinoma only, the expression of CD44v6 was significantly associated with the lymph node metastasis, invasion and pathological grade of the tumor (r = 0.47, P＜0.01; r = 5.04, P＜0.01). CD44sand CD44v6 were expressed in intraductal carcinoma of breast, the expression of CD44s and CD44v6 was significantly associated with lymph node metastases and invasion (P＜0.01). However, neither of them was expressed in the normal breast tissue. In addition, the expression of CD44v6 was closely related to the degree of cell differentiation of intraductal carcinoma of breast (x2= 5.68, P＜0.05). The expressional level of nm23mRNA was closely related to the degree of cell differentiation (P＜0.05) and lymph node metastasis (P＜0.01), but the expression of nm23 gene was not related to sex, age, and type of histological classification (P＞0.05).CONCLUSION: Patients with overexpression of CD44s and CD44v6 and low expression of nm23 mRNA have a higher lymph node metastatic rate and invasion. In addition, overexpression of CD44v6 is closely related to the degree of cell differentiation. Detection of the three genes is able to provide a reliable index to evaluate the invasion and metastasis of tumor cells.