Role Of CD44 Research Articles

Abstract 437: Cd146 Deficiency Leads to Accelerated Atherosclerosis in Mice Through Upregulation of Rantes

Rationale: The progression of atherosclerosis is based on the continued recruitment of leukocytes in the vessel wall. The previously described role of CD146 in leukocyte infiltration in vitro suggests a role for this endothelial junction molecule in the pathogenesis of atherosclerosis. However, its involvement in atherosclerotic plaques formation has never been investigated. Objective: We evaluated the role of CD146 in atherogenesis. Methods and Results: CD146 -/-/ApoE -/- and ApoE -/- mice were fed a Western diet for 24 weeks and were monitored for aortic wall thickness using high frequency ultrasound. The arterial wall thickness was significantly higher in CD146 deficient mice. We evidenced a significant increase of atheroma in both total aortic lesion and aortic sinus of CD146 deficient mice. In addition, atherosclerotic lesions were more inflammatory since CD146 deficient plaques contained more neutrophils and more macrophages. During atherosclerosis, circulating neutrophils were significantly increased in the absence of CD146. Consistent with the higher recruitment of inflammatory cells to the atheroma, we demonstrated that RANTES was up-regulated in CD146 deficient atherosclerotic arteries. In addition, CD146 deficient mice presented significant higher levels of circulating RANTES during atherosclerosis. Finally, we showed that macrophages were the source of RANTES and its production by CD146 null macrophages was also significantly increased through a mechanism dependent of p38-MAPK signaling pathway. Conclusions: Our data indicate that CD146 deficiency is associated with the upregulation of RANTES and increased inflammation of atheroma, which could influence the atherosclerotic plaque fate. Thus, these data identify CD146 as a potential new target for atherosclerosis treatment.

CD151, a laminin receptor showing increased expression in asthmatic patients, contributes to airway hyperresponsiveness through calcium signaling

Airway smooth muscle (ASM) contraction underpins airway constriction; however, underlying mechanisms for airway hyperresponsiveness (AHR) remain incompletely defined. CD151, a 4-transmembrane glycoprotein that associates with laminin-binding integrins, is highly expressed in the human lung. The role of CD151 in ASM function and its relationship to asthma have yet to be elucidated. We sought to ascertain whether CD151 expression is clinically relevant to asthma and whether CD151 expression affects AHR. Using immunohistochemical analysis, we determined the expression of CD151 in human bronchial biopsy specimens from patients with varying asthma severities and studied the mechanism of action of CD151 in the regulation of ASM contraction and bronchial caliber invitro, exvivo, and invivo. The number of CD151+ ASM cells is significantly greater in patients with moderate asthma compared with those in healthy nonasthmatic subjects. From loss- and gain-of-function studies, we reveal that CD151 is required for and enhances G protein-coupled receptor (GPCR)-induced peak intracellular calcium release, the primary determinant of excitation-contraction coupling. We show that the localization of CD151 can also be perinuclear/cytoplasmic and offer an explanation for a novel functional role for CD151 in supporting protein kinase C (PKC) translocation to the cell membrane in GPCR-mediated ASM contraction at this site. Importantly, CD151-/- mice are refractory to airway hyperreactivity in response to allergen challenge. We identify a role for CD151 in human ASM contraction. We implicate CD151 as a determinant of AHR in vivo, likely through regulation of GPCR-induced calcium and PKC signaling. These observations have significant implications in understanding the mechanism for AHR and the efficacy of new and emerging therapeutics.

The Role of CD44 in Glucose Metabolism in Prostatic Small Cell Neuroendocrine Carcinoma.

While prostatic adenocarcinomas are relatively indolent, some patients with advanced adenocarcinomas recur with small cell neuroendocrine carcinoma which is highly aggressive and lethal. Because glycolysis is a feature of malignancy and the degree of glycolysis generally correlates with tumor aggressiveness, we wanted to compare the metabolic differences and the molecular mechanisms involved between the two tumor types. In this study, and based on previous characterization, LNCaP and PC-3 prostate cancer cell lines were selected as models of prostatic adenocarcinoma and small cell neuroendocrine carcinoma, respectively. In addition to measuring glucose consumption, lactate secretion, and reactive oxygen species (ROS) levels, we performed metabolic profiling in these two model systems. The role of CD44 was studied by RNAi and lentivirus-mediated overexpression. Expression of key enzymes in glycolysis was studied using human tissue microarrays containing benign prostate, adenocarcinoma, and small cell neuroendocrine carcinoma. Results showed that glycolytic features of PC-3 cells were higher than that of LNCaP cells. PFKFB4 was overexpressed in human small cell carcinoma tissue versus adenocarcinoma tissue. CD44 regulated glucose metabolism, intracellular ROS, and cell proliferation in PC-3 cells. Inhibition of CD44 also sensitized PC-3 cells to carboplatin. In conclusion, this study suggests different pathways of glucose metabolism contribute to the disparate biologic behaviors of these two tumor types. CD44 is an important regulator of glucose metabolism in small cell neuroendocrine carcinoma and may be an important therapeutic target.

The Role of CD44 and ERM Proteins in Expression and Functionality of P-glycoprotein in Breast Cancer Cells.

Multidrug resistance (MDR) is often attributed to the over-expression of P-glycoprotein (P-gp), which prevents the accumulation of anticancer drugs within cells by virtue of its active drug efflux capacity. We have previously described the intercellular transfer of P-gp via extracellular vesicles (EVs) and proposed the involvement of a unique protein complex in regulating this process. In this paper, we investigate the role of these mediators in the regulation of P-gp functionality and hence the acquisition of MDR following cell to cell transfer. By sequentially silencing the FERM domain-binding proteins, Ezrin, Radixin and Moesin (ERM), as well as CD44, which we also report a selective packaging in breast cancer derived EVs, we have established a role for these proteins, in particular Radixin and CD44, in influencing the P-gp-mediated MDR in whole cells. We also report for the first time the role of ERM proteins in the vesicular transfer of functional P-gp. Specifically, we demonstrate that intercellular membrane insertion is dependent on Ezrin and Moesin, whilst P-gp functionality is governed by the integrity of all ERM proteins in the recipient cell. This study identifies these candidate proteins as potential new therapeutic targets in circumventing MDR clinically.

CD44highCD24low molecular signature determines the Cancer Stem Cell and EMT phenotype in Oral Squamous Cell Carcinoma

Almost all epithelial tumours contain cancer stem-like cells, which possess a unique property of self-renewal and differentiation. In oral cancer, several biomarkers including cell surface molecules have been exploited for the identification of this highly tumorigenic population. Implicit is the role of CD44 in defining CSCs but CD24 is not well-explored. Here we show that CD44highCD24low cells isolated from the oral cancer cell lines, not only express stem cell related genes but also exhibit Epithelial-to-Mesenchymal transition (EMT) characteristics. This CD44highCD24low population gives rise to all other cell types upon differentiation. Typical Cancer Stem Cell (CSC) phenotypes like increased colony formation, sphere forming ability, migration and invasion were also confirmed in CD44highCD24low cells. Drug transporters were found to be over-expressed in CD44highCD24low sub-population thereby contributing to elevated chemo-resistance. To validate our findings in-vivo, we determined the relative expression of CD44 and CD24 in clinical samples of OSCC patients. CD44 expression was consistently high whereas CD24 showed significantly lower expression in tumour tissues. Further, the gene expression profile of the CSC and non-CSC population unravels the molecular pathways which may contribute to stemness. We conclude that CD44highCD24low represents cancer stem-like cells in Oral Squamous Cell Carcinoma.

CD44 sensitivity of platelet activation, membrane scrambling and adhesion under high arterial shear rates.

CD44 is required for signalling of macrophage migration inhibitory factor (MIF), an anti-apoptotic pro-inflammatory cytokine. MIF is expressed and released from blood platelets, key players in the orchestration of occlusive vascular disease. Nothing is known about a role of CD44 in the regulation of platelet function. The present study thus explored whether CD44 modifies degranulation (P-selectin exposure), integrin activation, caspase activity, phosphatidylserine exposure on the platelet surface, platelet volume, Orai1 protein abundance and cytosolic Ca(2+)-activity ([Ca2+]i). Platelets from mice lacking CD44 (cd44(-/-)) were compared to platelets from corresponding wild-type mice (cd44(+/+)). In resting platelets, P-selectin abundance, α(IIb)β3 integrin activation, caspase-3 activity and phosphatidylserine exposure were negligible in both genotypes and Orai1 protein abundance, [Ca2+]i, and volume were similar in cd44(-/-) and cd44(+/+) platelets. Platelet degranulation and α(IIb)β3 integrin activation were significantly increased by thrombin (0.02 U/ml), collagen related peptide (CRP, 2 µg/ml and Ca(2+)-store depletion with thapsigargin (1 µM), effects more pronounced in cd44(-/-) than in cd44(+/+) platelets. Thrombin (0.02 U/ml) increased platelet [Ca2+]i, caspase-3 activity, phosphatidylserine exposure and Orai1 surface abundance, effects again significantly stronger in cd44(-/-) than in cd44(+/+) platelets. Thrombin further decreased forward scatter in cd44(-/-) and cd44(+/+) platelets, an effect which tended to be again more pronounced in cd44(-/-) than in cd44(+/+) platelets. Platelet adhesion and in vitro thrombus formation under high arterial shear rates (1,700 s(-1)) were significantly augmented in cd44(-/-) mice. In conclusion, genetic deficiency of CD44 augments activation, apoptosis and pro-thrombotic potential of platelets.

Therapeutic Potentials of CD151 shRNA in Targeting Metastasis of Triple Negative Breast Cancer Cell Line MDA-MB-231

Objective: CD151 is a master regulator of cell adhesion signalling and acts as a promoter in tumour progression. Induction of RNAi through shRNA expression holds great prospective in biomedical research. Bioinformatics approach used to predict potential shRNAs that knockdown CD151. The aim of present study is to investigate the role of CD151 in metastasis of triple negative breast cancer cells using shRNA. Methods: Triple negative breast cancer line, MDA-MB-231 obtained from NCCS Pune, India and expression of CD151 determined using western blot and RT-PCR analysis. Small hairpin RNA (shRNA) was constructed using pSilencer 2.1-U6 puro vector to knockdown CD151 expression. The role of CD151 in proliferation, apoptosis, migration, invasion and cell adhesion was evaluated by silencing CD151 gene using CD151shRNA. Results: RNA interference technology (RNAi) used to silence CD151 gene expression in MDA-MB-231 cells. Delivery of specific shRNA targeting human endogenous CD151 showed significant growth inhibition of MDA- MB-231 cells. The gene expression study by RT-PCR analysis showed that expression of CD151 at mRNA level reduced six fold with CD151 gene knockdown. CD151 gene silencing for 48h using shRNA decreased proliferation by 62.7%. CD151 knockdown also lead to the significant inhibition of metastasis and induced apoptosis. Conclusion: CD151 over expression is essential for tumour progression and our study shows that shRNA mediated gene silencing of CD151 decreases the metastasis, thus emphasizing CD151 as a prognostic marker and help in developing new therapeutics for treatment of triple negative breast cancer.

CD97/ADGRE5 Inhibits LPS Induced NF-κB Activation through PPAR-γ Upregulation in Macrophages.

CD97/ADGRE5 protein is predominantly expressed on leukocytes and belongs to the EGF-TM7 receptors family. It mediates granulocytes accumulation in the inflammatory tissues and is involved in firm adhesion of PMNC on activated endothelial cells. There have not been any studies exploring the role of CD97 in LPS induced NF-κB activation in macrophages. Therefore, we first measured the CD97 expression in LPS treated human primary macrophages and subsequently analyzed the levels of inflammatory factor TNF-α and transcription factor NF-κB in these macrophages that have been manipulated with either CD97 knockdown or overexpression. We found that a reported anti-inflammatory transcription factor, PPAR-γ, was involved in the CD97 mediated NF-κB suppression. Furthermore, by immunofluorescence staining, we established that CD97 overexpression not only inhibited LPS induced p65 expression in the nucleus but also promoted the PPAR-γ expression. Moreover, using CD97 knockout THP-1 cells, we further demonstrated that CD97 promoted PPAR-γ expression and decreased LPS induced NF-κB activation. In conclusion, CD97 plays a negative role in LPS induced NF-κB activation and TNF-α secretion, partly through PPAR-γ upregulation.

The role of CD44 in epithelial–mesenchymal transition and cancer development

CD44, a multi-structural and multifunctional transmembrane glycoprotein, was initially identified as a receptor for hyaluronan that participates in both physiological and pathological processes. CD44 is found to be closely linked to the development of various solid tumors. Molecular studies have revealed that high CD44 expression was correlated with the phenotypes of cancer stem cells and epithelial–mesenchymal transition, thereby contributing to tumor invasion, metastasis, recurrence, and chemoresistance. Correspondingly, blockade of CD44 has been demonstrated to be capable of attenuating the malignant phenotype, slowing cancer progression, and reversing therapy resistance. Clinical analyses showed that high CD44 expression is associated with poor survival of various cancer patients, indicating that CD44 can be a potential prognostic marker. In this review, we summarize recent research progress of CD44 on tumor biology and the clinical significance of CD44.

CD44 Influences Fibroblast Behaviors Via Modulation of Cell-Cell and Cell-Matrix Interactions, Affecting Survivin and Hippo Pathways.

CD44 has been studied in a wide variety of cell types, in a diverse array of cell behaviors and in a diverse range of signaling pathways. We now document a role for CD44 in mediating fibroblast behaviors via regulation of N-cadherin, extracellular matrix expression, Survivin and the Hippo pathway. Here, we report our findings on the roles of CD44 in modulating proliferation, apoptosis, migration and invasion of murine wild-type (WT-FB) and CD44 knockout dermal fibroblasts (CD44KO-FB). As we have documented in microvascular endothelial cells lacking CD44, we found persistent increased proliferation, reduced activation of cleaved caspase 3, increased initial attachment, but decreased strength of cell attachment in high cell density, post confluent CD44KO-FB cultures. Additionally, we found that siRNA knock-down of CD44 mimicked the behaviors of CD44KO-FB, restoring the decreases in N-cadherin, collagen type I, fibronectin, Survivin, nuclear fractions of YAP and phospho-YAP and decreased levels of cleaved caspase 3 to the levels observed in CD44KO-FB. Interestingly, plating CD44KO-FB on collagen type I or fibronectin resulted in significant decreases in secondary proliferation rates compared to plating cells on non-coated dishes, consistent with increased cell adhesion compared to their effects on WT-FB. Lastly, siRNA knockdown of CD44 in WT-FB resulted in increased fibroblast migration compared to WT-FB, albeit at reduced rates compared to CD44KO-FB. These results are consistent with CD44's pivotal role in modulating several diverse behaviors important for adhesion, proliferation, apoptosis, migration and invasion during development, growth, repair, maintenance and regression of a wide variety of mesenchymal tissues.

Immunoglobulin gene expression in umbilical cord blood-derived CD34+ hematopoietic stem/progenitor cells

Recently, immunoglobulin (Ig) expression was reported in a variety of non-B lineage cells, including myeloid cells. We assessed whether hematopoietic stem/progenitor cells (HSC/HPCs) can express Ig. With Gene Expression Omnibus (GEO) microarray database analysis, we found that IGHM was expressed with the highest frequency and level in umbilical cord blood CD34+ HSC/HPCs, followed by IGK@, IGHE, IGHD, IGHG1, and IGHA1, while IGL@ was nearly not expressed. Ig expression was further confirmed by molecular experiments and immunofluorescence. Moreover, HSC/HPCs-derived Ig displayed restricted/biased usages and VHDJH rearrangement patterns. These results suggest that Igs, especially IgM, may have a role in CD34+ HSC/HPCs function.

AB139. The role of CD44 in the osteoblastic differentiation from mesenchymal stem cells.

Background and objective Osteoblastic differentiation from mesenchymal stem cells (MSCs) is regulated by many hormonal and autocrine/paracrine factors. Recently, immunocytochemistry revealed that CD44, a transmembrane glycoprotein, is more expressed in osteoblasts than in MSCs during osteoblast differentiation (Kim et al., 2008). We examined whether CD44 might be involved in osteoblast differentiation.

CD97 promotion of gastric carcinoma lymphatic metastasis is exosome dependent.

BackgroundCD97 knockdown impairs the metastatic capacity of SGC-7901 gastric cancer cells. However, the role of CD97 in the distant lymphatic premetastatic niche formation of gastric cancer remains unknown.MethodsExosomes and the soluble fraction were isolated from SGC-L (an SGC-7901-cell-derived highly lymphatic metastatic cell line) and CD97-knockdown (SGC-L/CD97-kd) cells, and were co-cultured with gastric cancer cells. The metastatic capacity of the two cell lines was evaluated in vitro and in a footpad lymph node metastasis mouse model. Premetastatic-niche-formation-related proteins were examined immunohistochemically.ResultsCD97 expression was ninefold higher in SGC-L cells than in SGC-7901 cells. In vitro, exosomes or conditioned medium from the SGC-L cells enhanced cell proliferation (20 % increase) and invasion (30 % increase) as compared with that from SGC-L/CD97-kd cells (p < 0.01). Intrafootpad injections of SGC-L, but not SGC-L/CD97-kd exosomes or conditioned medium, strongly promoted SGC-L and SGC-L/CD97-kd cell accumulation in the draining lymph nodes (p < 0.01) and increased CD55, CD44v6, α5β1, CD31, epithelial cell adhesion molecule, and CD151 expression. Although the SGC-L/CD97-kd exosomes alone were insufficient for promotion of metastasis, they were partly aided by the SGC-L-cell-derived soluble fraction.ConclusionsThe CD97 small isoform promotes SGC-L cell lymphatic metastasis exosome dependently, and aided by the soluble fraction, the exosome-dependent CD97 plays a pivotal role in premetastatic niche formation.Electronic supplementary materialThe online version of this article (doi:10.1007/s10120-015-0523-y) contains supplementary material, which is available to authorized users.

Abstract 2377: Bone-derived osteopontin mediates the migration and stem-like properties of breast cancer cells

Abstract Metastatic breast cancer has an affinity for certain organs and tissues, a phenomenon termed organ tropism. Of particular interest is breast cancer's preference for bone, since this is the most common site of metastasis in breast cancer patients. In addition, research suggests that breast cancer cells that do metastasize may have stem-like properties, including the ability to self-renew and differentiate into a heterogeneous tumor. These cells can be identified by their high aldehyde dehydrogenase activity (ALDH) and/or CD44+CD24- phenotype. However, it is unclear whether properties of the organ microenvironment or the stem-like cancer cells (or both) facilitate metastatic organ tropism. In the current study, we tested the hypothesis that bone marrow-conditioned media (an ex vivo representation of the bone microenvironment) contains specific soluble factors that enhance the growth and migration of whole population and ALDHhiCD44+CD24- breast cancer cells. Bone marrow-conditioned media (BMCM) generated from the bones of athymic nude mice was analyzed for the presence and identity of soluble factors using protein arrays. Osteopontin (OPN) was detected in the BMCM in significant amounts by the protein array and confirmed by ELISA. OPN was then depleted from the BMCM using immunoprecipitation and migration of MDA-MB-231 and SUM-159 breast cancer cells to the BMCM was assessed. Results indicate that bone-derived OPN significantly enhances MDA-MB-231 and SUM-159 breast cancer cell migration (P&amp;lt;0.05). Additionally, bone-derived OPN enhances the migration of ALDHhiCD44+CD24- MDA-MB-231 breast cancer stem cells relative to their ALDHlowCD44-CD24+ counterparts (P&amp;lt;0.05). The effect of bone-derived OPN on the tumorsphere forming abilities of whole population and ALDHhiCD44+CD24- MDA-MB-231 was also assessed; bone-derived OPN significantly enhances the tumorsphere forming abilities of whole population and stem-like MDA-MB-231 breast cancer cells (P&amp;lt;0.05). The interaction between bone-derived OPN and its cell surface receptors CD44 and αvβ5 in breast cancer cell migration to BMCM was also investigated using blocking antibodies. We observed that both whole population MDA-MB-231 and SUM-159 breast cancer cells interact with bone-derived OPN via CD44 and αvβ5 (P&amp;lt;0.05). Ongoing studies are investigating the activation of OPN-mediated signaling pathways in breast cancer cells as well as the role of CD44 and other cell surface integrins in the tumorsphere forming abilities of breast cancer cells. Overall, elucidation of the interactions between bone-derived OPN and breast cancer cells could contribute to future development of novel therapeutics that interrupt these interactions in the bone marrow niche, thereby improving breast cancer patient prognosis. Citation Format: Graciella M. Pio. Bone-derived osteopontin mediates the migration and stem-like properties of breast cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2377. doi:10.1158/1538-7445.AM2015-2377

Abstract 2384: CD151-integrin complexes suppress ovarian tumor growth by repressing slug-mediated emt and canonical wnt signaling

Abstract The majority of human ovarian cancer is diagnosed in the late, metastatic stages and is highly resistant to current chemotherapies. The molecular and cellular mechanisms underlying the malignancy of ovarian cancer remain poorly understood. We report a surprising functional link between CD151-α31 integrin complexes and the malignancy of serous ovarian cancer. Analyses of clinical specimens indicate that CD151 expression is significantly reduced or diminished in approximately 90% of metastatic lesions, while it remains detectable in &amp;gt;40% of primary ovarian tumors. These observations suggest a putative tumor-suppressing role of CD151 in ovarian cancer. Indeed, our analyses with multiple ovarian cancer cell lines show that knocking down CD151 or α3β1 integrin markedly enhances tumor cell proliferation, growth and ascites production in nude mice. These changes are accompanied by impaired cell-cell contacts and aberrant expression of E-cadherin, Mucin 5AC and fibronectin, largely reminiscent of an epithelial to mesenchymal transition (EMT)-like change. Importantly, Slug, a master regulator of EMT, is markedly elevated upon CD151 removal. Knocking down Slug partially restores CD151-α3β1 integrin complex-dependent suppression of cell proliferation. Moreover, disruption of these adhesion protein complexes is accompanied by a concomitant activation of canonical Wnt signaling, including elevated levels of β-catenin and Axin-2 as well as resistance to the inhibition in β-catenin-dependent transcription complexes. Taken together, our study demonstrates that CD151-α3β1 integrin complexes suppress ovarian cancer malignancy by repressing Slug-mediated EMT and canonical Wnt signaling. Citation Format: Xiuwei H. Yang. CD151-integrin complexes suppress ovarian tumor growth by repressing slug-mediated emt and canonical wnt signaling. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2384. doi:10.1158/1538-7445.AM2015-2384

The Adhesion GPCR CD97/ADGRE5 inhibits apoptosis

The Adhesion G protein-coupled receptor (GPCR) CD97/ADGRE5 is induced, upregulated, and/or biochemically modified in various malignancies, compared to the corresponding normal tissues. As tumor cells are generally more resistant to apoptosis, we here studied the ability of CD97 to regulate tumor cell survival under apoptotic conditions. Stable overexpression of wild-type CD97 reduced serum starvation- and staurosporine-induced intrinsic and tumor necrosis factor (TNF)/cycloheximide-induced extrinsic apoptosis, indicated by an increase in cell viability, a lower percentage of cells within the subG0/G1 phase, expressing annexin V, or having condensed nuclei, and a reduction of DNA laddering. Protection from cell death by CD97 was accompanied by an inhibition of caspase activation and modulation of anti- and pro-apoptotic members of the BCL-2 superfamily. shRNA-mediated knockdown of CD97 and, in part, truncation of the seven-span transmembrane (TM7) region of CD97 increased caspase-mediated apoptosis. Protection from apoptosis required not only the TM7 region but also cleavage of the receptor at its GPCR proteolysis site (GPS), whereas alternative splicing of its extracellular domain had no effect. Together, our data indicate a role of CD97 in tumor cell survival.

Chronic endurance exercise affects paracrine action of CD31+ and CD34+ cells on endothelial tube formation.

We aimed to determine if chronic endurance-exercise habits affected redox status and paracrine function of CD34(+) and CD34(-)/CD31(+) circulating angiogenic cells (CACs). Subjects were healthy, nonsmoking men and women aged 18-35 yr and categorized by chronic physical activity habits. Blood was drawn from each subject for isolation and culture of CD34(+) and CD34(-)/CD31(+) CACs. No differences in redox status were found in any group across either cell type. Conditioned media (CM) was generated from the cultured CACs and used in an in vitro human umbilical vein endothelial cell-based tube assay. CM from CD34(+) cells from inactive individuals resulted in tube structures that were 29% shorter in length (P < 0.05) and 45% less complex (P < 0.05) than the endurance-trained group. CD34(-)/CD31(+) CM from inactive subjects resulted in tube structures that were 26% shorter in length (P < 0.05) and 42% less complex (P < 0.05) than endurance-trained individuals. Proteomics analyses identified S100A8 and S100A9 in the CM. S100A9 levels were 103% higher (P < 0.05) and S100A8 was 97% higher in the CD34(-)/CD31(+) CM of inactive subjects compared with their endurance-trained counterparts with no significant differences in either protein in the CM of CD34(+) CACs as a function of training status. Recombinant S100A8/A9 treatment at concentrations detected in inactive subjects' CD34(-)/CD31(+) CAC CM also reduced tube formation (P < 0.05). These findings are the first, to our knowledge, to demonstrate a differential paracrine role in CD34(+) and CD34(-)/CD31(+) CACs on tube formation as a function of chronic physical activity habits and identifies a differential secretion of S100A9 by CD34(-)/CD31(+) CACs due to habitual exercise.

Role of CD44 and Lewis Y antigen in chemo-resistance of locally advanced cervical squamous cell carcinoma (LACSCC) patients.

e16590 Background: Several mechanisms are involved in the development of resistance to therapy in LACSCC. Studies have shown that CD44 and Lewis Y antigen (LeY) form a complex that is associated wi...

CD44: molecular interactions, signaling and functions in the nervous system.

CD44 is the major surface hyaluronan (HA) receptor implicated in intercellular and cell-matrix adhesion, cell migration and signaling. It is a transmembrane, highly glycosylated protein with several isoforms resulting from alternative gene splicing. The CD44 molecule consists of several domains serving different functions: the N-terminal extracellular domain, the stem region, the transmembrane domain and the C-terminal tail. In the nervous system, CD44 expression occurs in both glial and neuronal cells. The role of CD44 in the physiology and pathology of the nervous system is not entirely understood, however, there exists evidence suggesting it might be involved in the axon guidance, cytoplasmic Ca2+ clearance, dendritic arborization, synaptic transmission, epileptogenesis, oligodendrocyte and astrocyte differentiation, post-traumatic brain repair and brain tumour development.

Abstract 564: CD146 Deficiency Leads to Accelerated Atherosclerosis in Mice

Atherosclerosis is a chronic inflammatory disease of the large vessels and its progression is based in part on the continued recruitment of macrophages in the inflammatory wall. The well described role of CD146 in leukocyte infiltration in vitro suggests a role for this endothelial junction molecule in the early stages of the formation of atherosclerotic plaques. However, the involvement of CD146 in atherogenesis has not been elucidated. To investigate the role of CD146 deficiency in atherosclerosis, CD146 knocked-out (KO) mice were bred with ApoE KO mice. Mice were fed a high-fat Western diet for 24 weeks and were monitored for aortic wall thickness using high frequency ultrasound. After 24 weeks of diet, the arterial wall thickness was significantly higher in CD146 deficient mice (0.19±0.01mm vs 0.27±0.01mm; p=0.012) and there was a significant 47 % increase (p=0.015) in total aortic lesion area, evaluated by histological oil red O coloration. However, mice weights and total cholesterol plasma levels were similar between the two groups of mice. We detected a 2-fold increase in macrophage recruitment to the atherosclerotic plaque of the double KO mice compared with ApoE KO mice, suggesting that the atherosclerotic lesions in these mice were more inflammatory. In addition, CD146 deficient plaques contained significantly less smooth muscle cells (p=0.036) and could be more vulnerable. We observed a maladaptive immune response in double KO mice since the circulating neutrophils and monocytes were significantly increased (p=0.008 and p=0.015 respectively) in the absence of CD146 whereas circulating T lymphocytes were significantly decreased (p=0.026). In a similar way, splenocytes isolated from double KO mice contained significantly lower levels of T cells (p=0.002), suggesting a default of adaptive immunity in the absence of CD146 during atherosclerosis. Our results demonstrated the involvement of CD146 in the progression of atherosclerosis in mice. Our data also suggest that CD146 is involved in the regulation of adaptive immune response and its absence lead to an inflammatory phenotype, which could influence atherosclerosis plaque fate. Thus, CD146 should be considered as a potential target for protection against atherosclerosis.