Engagement of CD44 modulates cyclooxygenase induction, VEGF generation, and proliferation in human vascular endothelial cells

The roles of hyaluronan in kidney development, physiology and disease

The hyaluronan (HA) matrix in the tissue microenvironment is crucial for maintaining homeostasis by regulating inflammatory signalling, endothelial-mesenchymal transition and cell migration. During development, covalent modifications and osmotic swelling of HA create mechanical forces that initiate midgut rotation, vascular patterning and branching morphogenesis. Together with its main cell surface receptor, CD44, HA establishes a physicochemical scaffold at the cell surface that facilitates the interaction and clustering of growth factors and receptors that is required for normal physiology. High-molecular-weight HA, tumour necrosis factor-stimulated gene 6, pentraxin 3 and CD44 form a stable pericellular matrix that promotes tissue regeneration and reduces inflammation. By contrast, breakdown of high-molecular-weight HA into depolymerized fragments by hyaluronidases triggers inflammatory signalling, leukocyte migration and angiogenesis, contributing to tissue damage and fibrosis in kidney disease. Targeting HA metabolism is challenging owing to its dynamic regulation and tissue-specific functions. Nonetheless, modulating HA matrix functions by targeting its binding partners holds promise as a therapeutic strategy for restoring tissue homeostasis and mitigating pathological processes. Further research in this area is warranted to enable the development of novel therapeutic approaches for kidney and other diseases characterized by dysregulated HA metabolism.

Hydrogels with Ultrasound-Treated Hyaluronic Acid Regulate CD44-Mediated Angiogenic Potential of Human Vascular Endothelial Cells In Vitro

The development of hydrogels that allow vascular endothelial cells to form capillary-like networks is critical for advancing tissue engineering and drug discovery. In this study, we developed hydrogels composed of phenolated hyaluronic acid (HA-Ph) with an average molecular weight of 490-159 kDa via sonication in an aqueous solution. These hydrogels were synthesized by the horseradish peroxidase-catalyzed crosslinking of phenol moieties in the presence of hydrogen peroxide and phenolated gelatin. The sonication-degraded HA-Ph (198 kDa) significantly enhanced the migration ability of human umbilical vein endothelial cells (HUVECs) on cell culture plates when added to the medium compared to the original HA-Ph (490 kDa) and less-degraded HA-Ph (312-399 kDa). In addition, HUVECs cultured on these hydrogels formed networks that did not occur on hydrogels made from the original HA-Ph. CD44 expression and PI3K gene expression, both markers related to angiogenesis, were 3.5- and 1.8-fold higher, respectively, in cells cultured on sonication-degraded HA-Ph hydrogels than in those cultured on hydrogels comprising the original HA-Ph. These results highlight the potential of hydrogels containing sonication-degraded HA-Ph for tissue engineering and drug-screening applications involving human vascular endothelial cells.

One-Pot Synthesis of Bioadhesive Double-Network Hydrogel Patch as Disposable Wound Dressing

Inventions of materials to achieve biocompatibility, bioadhesion, and easy manufacturing are the urgent demand for promoting wound healing in clinical treatment. Hyaluronic acid (HA) is probably the ideal candidate for current dressing materials due to its well-known biocompatibility. However, the unavoidable problem for HA dressings is their inherent low adhesiveness to wounds, which severely impairs their treatment efficacy, especially during body movement. Here, we report a one-pot facile fabrication of hybrid double-network polydopamine-HA (PDA-HA) hydrogel with significantly enhanced adhesiveness compared to the HA hydrogel. Besides the easy manufacturing and promoted effectiveness, the PDA-HA hydrogel could be vacuum-dried to form a patch, further benefitting from the convenience for storage and distribution. When applied on the wound, the PDA-HA patch quickly rehydrated by absorbing exudate and stuck tightly to the wound. The applied PDA-HA patches keep the wounds covered for more than 7 days against strenuous exercise. Thus, mouse full-thickness wounds treated with the PDA-HA patches exhibited increased healing rates, where epithelization was finished within 14 days. Moreover, the hydrogel dressing exhibited promoting effects on vascularization and cell proliferation/migration. Together with the easy manufacturing procedure, good adhesion/adaptation, and promotion of wound healing, the PDA-HA patch holds great potential for future clinical translation.

CD44 In Sarcomas: A Comprehensive Review and Future Perspectives

It is widely accepted that the tumor microenvironment, particularly the extracellular matrix, plays an essential role in the development of tumors through the interaction with specific protein-membrane receptors. One of the most relevant proteins in this context is the transmembrane protein CD44. The role of CD44 in tumor progression, invasion, and metastasis has been well established in many cancers, although a comprehensive review concerning its role in sarcomas has not been published. CD44 is overexpressed in most sarcomas and several in vitro and in vivo experiments have shown a direct effect on tumor progression, dissemination, and drug resistance. Moreover, CD44 has been revealed as a useful marker for prognostic and diagnostic (CD44v6 isoform) in osteosarcoma. Besides, some innovative treatments such as HA-functionalized liposomes therapy have become an excellent CD44-mediated intracellular delivery system for osteosarcoma. Unfortunately, the reduced number of studies deciphering the prognostic/diagnostic value of CD44 in other sarcoma subgroups, neither than osteosarcoma, in addition to the low number of patients involved in those studies, have produced inconclusive results. In this review, we have gone through the information available on the role of CD44 in the development, maintenance, and progression of sarcomas, analyzing their implications at the prognostic, therapeutic, and mechanistic levels. Moreover, we illustrate how research involving the specific role of CD44 in the different sarcoma subgroups could suppose a chance to advance towards a more innovative perspective for novel therapies and future clinical trials.

Role of CD44 isoforms in epithelial-mesenchymal plasticity and metastasis

Cellular plasticity lies at the core of cancer progression, metastasis, and resistance to treatment. Stemness and epithelial-mesenchymal plasticity in cancer are concepts that represent a cancer cell's ability to coopt and adapt normal developmental programs to promote survival and expansion. The cancer stem cell model states that a small subset of cancer cells with stem cell-like properties are responsible for driving tumorigenesis and metastasis while remaining especially resistant to common chemotherapeutic drugs. Epithelial-mesenchymal plasticity describes a cancer cell's ability to transition between epithelial and mesenchymal phenotypes which drives invasion and metastasis. Recent research supports the existence of stable epithelial/mesenchymal hybrid phenotypes which represent highly plastic states with cancer stem cell characteristics. The cell adhesion molecule CD44 is a widely accepted marker for cancer stem cells, and it lies at a functional intersection between signaling networks regulating both stemness and epithelial-mesenchymal plasticity. CD44 expression is complex, with alternative splicing producing many isoforms. Interestingly, not only does the pattern of isoform expression change during transitions between epithelial and mesenchymal phenotypes in cancer, but these isoforms have distinct effects on cell behavior including the promotion of metastasis and stemness. The role of CD44 both downstream and upstream of signaling pathways regulating epithelial-mesenchymal plasticity and stemness make this protein a valuable target for further research and therapeutic intervention.

Discovery of surface biomarkers for cell mechanophenotype via an intracellular protein-based enrichment strategy

Cellular mechanophenotype is often a defining characteristic of conditions like cancer malignancy/metastasis, cardiovascular disease, lung and liver fibrosis, and stem cell differentiation. However, acquiring living cells based on mechanophenotype is challenging for conventional cell sorters due to a lack of biomarkers. In this study, we demonstrate a workflow for surface protein discovery associated with cellular mechanophenotype. We sorted heterogeneous adipose-derived stem/stromal cells (ASCs) into groups with low vs. high lamin A/C, an intracellular protein linked to whole-cell mechanophenotype. Proteomic data of enriched groups identified surface protein candidates as potential biochemical proxies for ASC mechanophenotype. Select surface biomarkers were used for live-cell enrichment, with subsequent single-cell mechanical testing and lineage-specific differentiation. Ultimately, we identified CD44 to have a strong inverse correlation with whole-cell elastic modulus, with CD44^lo cells exhibiting moduli three times greater than that of CD44^hi cells. Functionally, these stiff and soft ASCs showed enhanced osteogenic and adipogenic differentiation potential, respectively. The described workflow can be replicated for any phenotype with a known correlated intracellular protein, allowing for the acquisition of live cells for further characterization, diagnostics, or therapeutics.

Development of a Novel Anti-CD44 Monoclonal Antibody for Multiple Applications against Esophageal Squamous Cell Carcinomas

CD44 is a cell surface glycoprotein, which is expressed on normal cells, and overexpressed on cancer cells. CD44 is involved in cell adhesion, migration, proliferation, survival, stemness, and chemo-resistance. Therefore, CD44 is thought to be a promising target for cancer diagnosis and therapy. In this study, we established anti-CD44 monoclonal antibodies (mAbs) by immunizing mice with a CD44 variant (CD44v3-10) ectodomain and screening using enzyme-linked immunosorbent assay. We then characterized them using flow cytometry, Western blotting, and immunohistochemistry. One of the established clones (C₄₄Mab-46; IgG₁, kappa) reacted with CD44 standard isoform (CD44s)-overexpressed Chinese hamster ovary-K1 cells (CHO/CD44s) or esophageal squamous cell carcinoma (ESCC) cell lines (KYSE70 and KYSE770). The apparent K_D of C₄₄Mab-46 for CHO/CD44s, KYSE70, and KYSE770 was 1.1 × 10^-8 M, 4.9 × 10^-8 M, and 4.1 × 10^-8 M, respectively. C₄₄Mab-46 detected CD44s of CHO/CD44s and KYSE70, and CD44 variants of KYSE770 in Western blot analysis. Furthermore, C₄₄Mab-46 strongly stained the formalin-fixed paraffin-embedded ESCC tissues in immunohistochemistry. Collectively, C₄₄Mab-46 is very useful for detecting CD44 in various applications.

CD44 in Ovarian Cancer Progression and Therapy Resistance-A Critical Role for STAT3

Despite significant progress in cancer therapy over the last decades, ovarian cancer remains the most lethal gynecologic malignancy worldwide with the five-year overall survival rate less than 30% due to frequent disease recurrence and chemoresistance. CD44 is a non-kinase transmembrane receptor that has been linked to cancer metastatic progression, cancer stem cell maintenance, and chemoresistance development via multiple mechanisms across many cancers, including ovarian, and represents a promising therapeutic target for ovarian cancer treatment. Moreover, CD44-mediated signaling interacts with other well-known pro-tumorigenic pathways and oncogenes during cancer development, such as signal transducer and activator of transcription 3 (STAT3). Given that both CD44 and STAT3 are strongly implicated in the metastatic progression and chemoresistance of ovarian tumors, this review summarizes currently available evidence about functional crosstalk between CD44 and STAT3 in human malignancies with an emphasis on ovarian cancer. In addition to the role of tumor cell-intrinsic CD44 and STAT3 interaction in driving cancer progression and metastasis, we discuss how CD44 and STAT3 support the pro-tumorigenic tumor microenvironment and promote tumor angiogenesis, immunosuppression, and cancer metabolic reprogramming in favor of cancer progression. Finally, we review the current state of therapeutic CD44 targeting and propose superior treatment possibilities for ovarian cancer.

siRNA-mediated silencing of CD44 delivered by Jet Pei enhanced Doxorubicin chemo sensitivity and altered miRNA expression in human breast cancer cell line (MDA-MB468)

CD44, as a superficial cellular glycoprotein, is an essential factor in cell-cell and cell-matrix interaction. The CD44 expression level has been substantially up-regulated in breast cancer, and this upregulation facilitates tumor proliferation and angiogenesis. This study aims to evaluate the combination therapy of Jet Pei/CD44-specific-siRNA/doxorubicin in breast cancer MDA-MB468 cell line. The MTT assay, wound healing test, colony formation assay, DAPI staining, and flow cytometry were performed to investigate the tumoral cell viability, migration, clonogenesis, and apoptosis progression. The quantitative real-time PCR (qRT-PCR) was performed to demonstrate the CD44 expression level. Finally, the effect of CD44 silencing on the expression of VEGF, CXCR4, MMP9, and MiR-142-3p was measured. The combination of CD44-specific-siRNA with doxorubicin decreased tumoral metastasis, proliferation, invasion, and migration, and increased apoptosis in MDA-MB468 cells. In conclusions, CD44 can serve as a therapeutic target in breast cancer. Moreover, the combination therapy of CD44-specific-siRNA with doxorubicin can be a promising treatment for patients with breast cancer.

A review on the wide range applications of hyaluronic acid as a promising rejuvenating biomacromolecule in the treatments of bone related diseases

Hyaluronic acid (HA) is a multifunctional high molecular weight polysaccharide produced by synoviocytes, fibroblasts, and chondrocytes, and is naturally found in many tissues and fluids, and more abundantly in articular cartilage and synovial fluid. Naturally occurring HA is thought to participate in many biological processes, such as regulation of cell adhesion and cell motility, manipulation of cell differentiation and proliferation, and providing mechanical properties to tissues (Girish and Kemparaju, 2007). Due to its excellent physicochemical properties such as high viscosity, elasticity, biodegradability, biocompatibility, nontoxicity, and nonimmunogenicity, HA based formulations have a wide range of applications and serves as a promising rejuvenating biomacromolecule in biomedical applications. In recent decades, HA is currently a popular topic, and has been widely used in bone related diseases for its remarkable efficacy in articular cartilage lubrication, analgesia, anti-inflammation, immunomodulatory, chondroprotection, anti-cancer and etc. Moreover, the safety and tolerability of HA based formulations have also been well-documented for treatment of various types of bone related diseases (Chen et al., 2018). This review gives a deep understanding on the special benefits and provides a mechanism-based rationale for the use of HA in bone related diseases conditions with special reference to osteoarthritis (OA), rheumatoid arthritis (RA), bone metastatic cancers.

The role of CD44 in pathological angiogenesis

Angiogenesis is required for normal development and occurs as a pathological step in a variety of disease settings, such as cancer, ocular diseases, and ischemia. Recent studies have revealed the role of CD44, a widely expressed cell surface adhesion molecule, in promoting pathological angiogenesis and the development of its associated diseases through its regulation of diverse function of endothelial cells, such as proliferation, migration, adhesion, invasion, and communication with the microenvironment. Conversely, the absence of CD44 expression or inhibition of its function impairs pathological angiogenesis and disease progression. Here, we summarize the current understanding of the roles of CD44 in pathological angiogenesis and the underlying cellular and molecular mechanisms.

Epigenome-wide association study in healthy individuals identifies significant associations with DNA methylation and PBMC extract VEGF-A concentration

INTRODUCTION

Vascular endothelial growth factor A (VEGF-A) is a chemokine that induces proliferation and migration of vascular endothelial cells and is essential for both physiological and pathological angiogenesis. It is known for its high heritability (> 60%) and involvement in most common morbidities, which makes it a potentially interesting biomarker. Large GWAS studies have already assessed polymorphisms related to VEGF-A. However, no previous research has provided epigenome-wide insight in regulation of VEGF-A.

METHODS

VEGF-A concentrations of healthy participants from the STANISLAS Family Study (n = 201) were comprehensively assessed for association with DNA methylation. Genome-wide DNA methylation profiles were determined in whole blood DNA using the 450K Infinium BeadChip Array (Illumina). VEGF-A concentration in PBMC extracts was detected using a high-sensitivity multiplex Cytokine Array (Randox Laboratories, UK).

RESULTS

Epigenome-wide association analysis identified 41 methylation sites significantly associated with VEGF-A concentrations derived from PBMC extracts. Twenty CpG sites within 13 chromosomes reached Holm-Bonferroni significance. Significant values ranged from P = 1.08 × 10-7 to P = 5.64 × 10-15.

CONCLUSION

This study exposed twenty significant CpG sites linking DNA methylation to VEGF-A concentration. Methylation detected in promoter regions, such as TPX2 and HAS-1, could explain previously reported associations with the VEGFA gene. Methylation may also help in the understanding of the regulatory mechanisms of other genes located in the vicinity of detected CpG sites.

Ligand-installed anti-VEGF genomic nanocarriers for effective gene therapy of primary and metastatic tumors

The systemic dosage regimen exhibited low therapeutic efficacy and incurred severe adverse effect, thus, the development of tumor-targeted therapeutics is crucial important for tumor precision therapy. Herein, the active targeted modulation of tumor microenvironments was schemed by developing hyaluronic acid-installed genomic nanocarriers (HA-NPs) for effectively ablation of both primary and metastatic tumors through anti-vascular endothelial growth factor (anti-VEGF) approach. The anti-VEGF genomic payloads were strategically packaged into the well-defined synthetic nanocarriers by layer-by-layer preparation strategy, exhibiting high colloidal stability and much lower cell viability than the cationic gene carriers. Besides, the HA-NPs could specifically and efficiently internalize with cancer cells for efficient intracellular gene delivery, leading to high gene transfection efficacy. Moreover, it further demonstrated efficient extravasation, high accumulation and deep penetration in tumors, which markedly facilitated tumor-targeted expression of anti-VEGF genomic payloads for inhabitation of neo-vasculature, consecutively contributing to potent ablation of solid tumors. In addition, the ligand-installed nanocarriers facilitated systemic treatment of melanoma lung metastasis by the expressed anti-VEGF proteins, which were extensively spread along blood circulation and metastatic niches to diminish the formation of neovasculature for tumorigenesis. Therefore, the proposed anti-VEGF genomic nanocarriers could shed intriguing implication in effectively treatment of primary tumors and metastasis.

Cell type-specific endometrial transcriptome changes during initial recognition of pregnancy in the mare

Previous endometrial gene expression studies during the time of conceptus migration did not provide final conclusions on the mechanisms of maternal recognition of pregnancy (MRP) in the mare. This called for a cell type-specific endometrial gene expression analysis in response to embryo signals to improve the understanding of gene expression regulation in the context of MRP. Laser capture microdissection was used to collect luminal epithelium (LE), glandular epithelium and stroma from endometrial biopsies from Day 12 of pregnancy and Day 12 of the oestrous cycle. RNA sequencing (RNA-Seq) showed greater expression differences between cell types than between pregnant and cyclic states; differences between the pregnant and cyclic states were mainly found in LE. Comparison with a previous RNA-Seq dataset for whole biopsy samples revealed the specific origin of gene expression differences. Furthermore, genes specifically differentially expressed (DE) in one cell type were found that were not detectable as DE in biopsies. Overall, this study revealed spatial information about endometrial gene expression during the phase of initial MRP. The conceptus induced changes in the expression of genes involved in blood vessel development, specific spatial regulation of the immune system, growth factors, regulation of prostaglandin synthesis, transport prostaglandin receptors, specifically prostaglandin F receptor (PTGFR) in the context of prevention of luteolysis.

Enhanced angiogenesis by the hyaluronic acid hydrogels immobilized with a VEGF mimetic peptide in a traumatic brain injury model in rats

Angiogenesis plays an important role in brain injury repair, which contributes to the reconstruction of regenerative neurovascular niche for promoting axonal regeneration in the lesion area. As a major component of developing brain extracellular matrix, hyaluronic acid (HA) has attracted more attention as a supporting matrix for brain repair. In the present study, HA-KLT hydrogel was developed via modifying HA with a VEGF mimetic peptide of KLT (KLTWQELYQLKYKGI). The characterization of the hydrogel shows that it could provide a porous, three-dimensional scaffold structure, which has a large specific surface area available for cell adhesion and interaction. Compared with the unmodified HA hydrogel, the HA-KLT hydrogel could effectively promote the attachment, spreading and proliferation of endothelial cells in vitro. Furthermore, the pro-angiogenic ability of hydrogels in vivo was evaluated by implanting them into the lesion cavities in the injured rat brain. Our results showed that the hydrogels could form a permissive interface with the host tissues at 4 weeks after implantation. Moreover, they could efficiently inhibit the formation of glial scars at the injured sites. The HA-KLT hydrogel could significantly increase the expression of endoglin/CD105 and promote the formation of blood vessels, suggesting that HA-KLT hydrogel promoted angiogenesis in vivo. Collectively, the HA-KLT hydrogel has the potential to repair brain defects by promoting angiogenesis and inhibiting the formation of glial-derived scar tissue.

Müller cells in pathological retinal angiogenesis

Müller cells are the major glial cells spanning the entire layer of the retina and maintaining retinal structure. Under pathological conditions, Müller cells are involved in retinal angiogenesis, a process of growing new blood vessels from pre-existing capillaries. In response to hypoxia, high glucose, and inflammation conditions, multiple signaling pathways are activated in Müller cells, followed by the increased production of proangiogenic factors including vascular endothelial growth factor, basic fibroblast growth factor, matrix metalloproteinases, Netrin-4, and angiopoietin-like 4. Expression of antiangiogenic factors is also downregulated in Müller cells. Besides, proliferation and dedifferentiation of Müller cells facilitates retinal angiogenesis. In this review, we summarized molecular mechanisms of Müller cells-related retinal angiogenesis. The potential of Müller cells as a therapeutic target for retinal angiogenesis was also discussed.

The Wnt modulator ICG‑001 mediates the inhibition of nasopharyngeal carcinoma cell migration in vitro via the miR‑150/CD44 axis

The Wnt signaling pathway is known to serve an important role in the control of cell migration. The present study analyzed the mechanisms underlying the in vitro modulation of the migration of nasopharyngeal carcinoma (NPC) cells by the CREB‑binding protein/catenin antagonist and Wnt modulator ICG‑001. The results revealed that ICG‑001‑mediated inhibition of tumor cell migration involved downregulated mRNA and protein expression of the Wnt target gene cluster of differentiation (CD)44. It was also demonstrated that ICG‑001 downregulated the expression of CD44, and this effect was accompanied by restored expression of microRNA (miRNA)‑150 in various NPC cell lines. Using a CD44 3'‑untranslated region luciferase reporter assay, miR‑150 was confirmed to be a novel CD44‑targeting miRNA, which could directly target CD44 and subsequently regulate the migration of NPC cells. The present study provides further insight into the inhibition of tumor cell migration through the modulation of miRNA expression by the Wnt modulator ICG‑001.

The biology and role of CD44 in cancer progression: therapeutic implications

CD44, a non-kinase transmembrane glycoprotein, is overexpressed in several cell types including cancer stem cells and frequently shows alternative spliced variants that are thought to play a role in cancer development and progression. Hyaluronan, the main ligand for CD44, binds to and activates CD44 resulting in activation of cell signaling pathways that induces cell proliferation, increases cell survival, modulates cytoskeletal changes, and enhances cellular motility. The different functional roles of CD44 standard (CD44s) and specific CD44 variant (CD44v) isoforms are not fully understood. CD44v contain additional peptide motifs that can interact with and sequester growth factors and cytokines at the cell surface thereby functioning as coreceptors to facilitate cell signaling. Moreover, CD44v were expressed in metastasized tumors, whereas switching between CD44v and CD44s may play a role in regulating epithelial to mesenchymal transition (EMT) and in the adaptive plasticity of cancer cells. Here, we review current data on the structural and functional properties of CD44, the known roles for CD44 in tumorigencity, the regulation of CD44 expression, and the potential for targeting CD44 for cancer therapy.

Angiogenesis for tumor vascular normalization of Endostar on hepatoma 22 tumor-bearing mice is involved in the immune response

Tumor vascular normalization involved in immune response is beneficial to the chemotherapy of tumors. Recombinant human endostatin (Endostar), an angiogenesis inhibitor, has been demonstrated to be effective in hepatocellular cancer (HCC). However, its vascular normalization in HCC and the role of the immune response in angiogenesis were unclear. In the present study, effects of Endostar on tumor vascular normalization were evaluated in hepatoma 22 (H22) tumor-bearing mice. Endostar was able to inhibit the proliferation and infiltration of tumor cells and improve α-fetoprotein, tumor necrosis factor-α and cyclic adenosine 5′-phosphate levels in the serum of H22-bearing mice, as well as the protein expression levels of the immune factors interferon-γ and cluster of differentiation (CD)86 in liver tissue. Endostar also exhibited more marked downregulation of the levels of vascular endothelial growth factor, CD31, matrix metalloproteinase (MMP)-2, MMP-9 and interleukin-17 during day 3–9 treatment, resulting in short-term normalization of tumor blood vessels. The period of vascular normalization was 3–9 days. The results of the present study demonstrated that Endostar was able to induce the period of vascular normalization, contributing to a more efficacious means of HCC treatment combined with other chemotherapy, and this effect was associated with the immune response. It may be concluded that Endostar inhibited immunity-associated angiogenesis behaviors of vascular endothelial cells in response to HCC. The results of the present study provided more reasonable possibility for the combination therapy of Endostar for the treatment of HCC.

Creation of disease-inspired biomaterial environments to mimic pathological events in early calcific aortic valve disease

An insufficient understanding of calcific aortic valve disease (CAVD) pathogenesis remains a major obstacle in developing treatment strategies for this disease. The aim of the present study was to create engineered environments that mimic the earliest known features of CAVD and apply this in vitro platform to decipher relationships relevant to early valve lesion pathobiology. Glycosaminoglycan (GAG) enrichment is a dominant hallmark of early CAVD, but culture of valvular interstitial cells (VICs) in biomaterial environments containing pathological amounts of hyaluronic acid (HA) or chondroitin sulfate (CS) did not directly increase indicators of disease progression such as VIC activation or inflammatory cytokine production. However, HA-enriched matrices increased production of vascular endothelial growth factor (VEGF), while matrices displaying pathological levels of CS were effective at retaining lipoproteins, whose deposition is also found in early CAVD. Retained oxidized low-density lipoprotein (oxLDL), in turn, stimulated myofibroblastic VIC differentiation and secretion of numerous inflammatory cytokines. OxLDL also increased VIC deposition of GAGs, thereby creating a positive feedback loop to further enrich GAG content and promote disease progression. Using this disease-inspired in vitro platform, we were able to model a complex, multistep pathological sequence, with our findings suggesting distinct roles for individual GAGs in outcomes related to valve lesion progression, as well as key differences in cell-lipoprotein interactions compared with atherosclerosis. We propose a pathogenesis cascade that may be relevant to understanding early CAVD and envision the extension of such models to investigate other tissue pathologies or test pharmacological treatments.

Inhibition of Hyaluronic Acid Synthesis Suppresses Angiogenesis in Developing Endometriotic Lesions

Background

The development and long-term survival of endometriotic lesions is crucially dependent on an adequate vascularization. Hyaluronic acid (HA) through its receptor CD44 has been described to be involved in the process of angiogenesis.

Objective

To study the effect of HA synthesis inhibition using non-toxic doses of 4-methylumbelliferone (4-MU) on endometriosis-related angiogenesis.

Materials and Methods

The cytotoxicity of different in vitro doses of 4-MU on endothelial cells was firstly tested by means of a lactate dehydrogenase assay. The anti-angiogenic action of non-cytotoxic doses of 4-MU was then assessed by a rat aortic ring assay. In addition, endometriotic lesions were induced in dorsal skinfold chambers of female BALB/c mice, which were daily treated with an intraperitoneal injection of 0.9% NaCl (vehicle group; n = 6), 20mg/kg 4-MU (n = 8) or 80mg/kg 4-MU (n = 7) throughout an observation period of 14 days. The effect of 4-MU on their vascularization, survival and growth were studied by intravital fluorescence microscopy, histology and immunohistochemistry.

Main Results

Non-cytotoxic doses of 4-MU effectively inhibited vascular sprout formation in the rat aortic ring assay. Endometriotic lesions in dorsal skinfold chambers of 4-MU-treated mice dose-dependently exhibited a significantly smaller vascularized area and lower functional microvessel density when compared to vehicle-treated controls. Histological analyses revealed a downregulation of HA expression in 4-MU-treated lesions. This was associated with a reduced density of CD31-positive microvessels within the lesions. In contrast, numbers of PCNA-positive proliferating and cleaved caspase-3-positive apoptotic cells did not differ between 4-MU-treated and control lesions.

Conclusions

The present study demonstrates for the first time that targeting the synthesis of HA suppresses angiogenesis in developing endometriotic lesions. Further studies have to clarify now whether in the future this anti-angiogenic effect can be used beneficially for the treatment of endometriosis.

Curcumin Induces Apoptosis of Colorectal Cancer Stem Cells by Coupling with CD44 Marker

This study investigated the effect of curcumin on colorectal cancer stem cells (CCSCs) and its possible mechanism. Comparison of the metabolic profiles of human adenomatous polyp (N = 61) and colorectal cancer (CRC) (N = 57) tissue found statistically significant differences (p < 0.05) in their composition of adenosine monophosphate (AMP), adenine, 5'-methythioadenosine, 3-hydroxybutyric acid, prostaglandin E2, threonine, and glutamine. Our cell culture model study found that curcumin treatment (50 μM for 48 h) did indeed increase apoptosis of CRC cells as well as of CCSCs, but at a significant level only in CD44(+) cells. Further metabolic profile studies of the CRC, CD44(+), and CD44(-) cells indicated that curcumin treatment increased glyceraldehyde and hydroxypropionic acid in CD44(-) cells but decreased glutamine content in both curcumin-treated CRC and CD44(+) cells. Based on our comparison of the metabolic profiles of human tissues and cancer cells, we suggest that curcumin might couple with CD44 and that curcumin-CD44(+) coupling at the cell membrane might have some blocking effect on the transport of glutamine into the cells, thus decreasing the glutamine content in the CD44(+) cells and inducing apoptosis.

Changes in Expression of Nestin, CD44, Vascular Endothelial Growth Factor, and Glutamine Synthetase by Mature Müller Cells After Dedifferentiation

PURPOSE

Müller cells are dedifferentiated after retinal injuries and are transformed into nestin-positive progenitor cells that play crucial roles in remodeling. The purpose of this study was to determine the changes in the expression of nestin, CD44 (a receptor of hyaluronan), vascular endothelial growth factor (VEGF), and glutamine sythetase in cultured Müller cells after dedifferentiation by basic fibroblast growth factor (bFGF) and insulin.

METHODS

Cells from a rat retinal Müller cell line (TR-MUL5) and from primary rat retinal Müller cells were grown in culture. The cells were incubated in various concentrations of bFGF (1.0, 10, 100 ng/mL) with or without insulin (5 μM) for 48 h. Changes in the expression of nestin, CD44, VEGF, and glutamine synthetase were determined by immunoblot and immunohistochemistry.

RESULTS

Exposure of TR-MUL5 cells to 10 ng/mL of bFGF led to the maximum increase in nestin by 1.5-fold, whereas the exposure had no effects on the expression of CD44. Addition of insulin (5 μM) to the bFGF significantly increased the CD44 level in TR-MUL5 cells by 1.4-fold. Immunohistochemistry showed that the combined treatments also upregulated the expression of nestin and CD44 in primary retinal Müller cells. Immunoblot analyses showed that exposure to bFGF and insulin caused significant increases of nestin (4.9-fold), CD44 (3.4-fold), and VEGF (1.44-fold) and decreases in glutamine synthetase (0.7-fold).

CONCLUSIONS

The inflammation and angiogenesis that develop after retinal injuries may be due to an upregulation of CD44 and VEGF by the dedifferentiated Müller cells.

The potential role of COX-2 in cancer stem cell-mediated canine mammary tumor initiation: an immunohistochemical study

Increasing evidence suggests that cancer stem cells (CSCs) are responsible for tumor initiation and maintenance. Additionally, it is becoming apparent that cyclooxygenase (COX) signaling is associated with canine mammary tumor development. The goals of the present study were to investigate COX-2 expression patterns and their effect on CSC-mediated tumor initiation in primary canine mammary tissues and tumorsphere models using immunohistochemistry. Patterns of COX-2, CD44, octamer-binding transcription factor (Oct)-3/4, and epidermal growth factor receptor (EGFR) expression were examined in malignant mammary tumor (MMT) samples and analyzed in terms of clinicopathological characteristics. COX-2 and Oct-3/4 expression was higher in MMTs compared to other histological samples with heterogeneous patterns. In MMTs, COX-2 expression correlated with tumor malignancy features. Significant associations between COX-2, CD44, and EGFR were observed in low-differentiated MMTs. Comparative analysis showed that the levels of COX-2, CD44, and Oct-3/4 expression varied significantly among TSs of three histological grades. Enhanced COX-2 staining was consistently observed in TSs. Similar levels of staining intensity were found for CD44 and Oct-3/4, but EGFR expression was weak. Our findings indicate the potential role of COX-2 in CSC-mediated tumor initiation, and suggest that COX-2 inhibition may help treat canine mammary tumors by targeting CSCs.

Soluble CD44 and vascular endothelial growth factor levels in patients with acute primary angle closure

PURPOSE

Acute elevation of intraocular pressure (IOP) in acute primary angle closure (APAC) can cause huge damage to the variable cells in the eye; however, the mechanisms that connect the two processes still remain unclear. In this study, we aim to evaluate the levels of soluble CD44 (sCD44) and vascular endothelial growth factor (VEGF) in the aqueous humour of acute primary angle closure patients.

METHODS

This study included 24 eyes of 24 APAC patients (11 eyes with current APAC and 13 eyes with previous APAC) and 15 eyes of 15 cataract subjects. Clinical data were acquired, and aqueous humour was collected. The levels of sCD44 and VEGF in the aqueous humour were determined by ELISA and magnetic bead immunoassay technique.

RESULTS

The concentrations of the sCD44 and VEGF in the current APAC were 9.9 ± 8.8 ng/ml and 2440.2 ± 2107.1 ng/ml, respectively, which were significantly higher when compared to the previous APAC group (p = 0.001) and cataract (p < 0.001); however, there were no significant differences between the group with previous APAC and with cataract. Higher IOP was associated with higher concentration of sCD44 (Rho = 0.617, p = 0.001). The concentration of the VEGF in aqueous humour of APAC patients was closely related to the sCD44 levels (Rho = 0.752, p < 0.001).

CONCLUSION

After acute increase of IOP in the APAC, the level of sCD44 and VEGF increased significantly in the aqueous humour. The damage due to high IOP may therefore be mediated through the release of sCD44.

Pilot study on the effects of high molecular weight sodium hyaluronate in the treatment of chronic pharyngitis

Although several therapeutic approaches are available at present for the treatment of chronic pharyngitis, new therapeutic strategies acting on pharyngeal mucous function should be investigated in order to improve symptoms and quality of life. High-molecular weight hyaluronate performs important functions on mucociliary clearance, tissues hydration, defense against micro-organisms, and on tissue repair as well, but at present there is no clinical evidence of its exogenous use in patients with chronic pharyngitis. Our open, randomized controlled study was carried out to investigate efficacy, and tolerability of exogenous high molecular weight sodium hyaluronate (SH) at the dosage of 9 mg three times a day for a period of 30 days, in patients with chronic pharyngitis. Results show significant improvements of symptoms and cytology in active group (A, n = 10) vs. control group (B, n = 10). Good compliance and no adverse events were reported in group A. In conclusion, SH was effective and safe in patients with chronic pharyngitis.

Knock-down of CD44 regulates endothelial cell differentiation via NFκB-mediated chemokine production

A striking feature of microvascular endothelial cells is their capacity to fuse and differentiate into tubular structures when grown in three-dimensional (3D) extracellular matrices, in collagen or Matrigel, mimicking the in vivo blood vessel formation. In this study we demonstrate that human telomerase-immortalised foreskin microvascular endothelial (TIME) cells express high levels of the hyaluronan receptor CD44 and the hyaluronidase HYAL2. Knock-down of CD44 or HYAL2 resulted in an inability of TIME cells to form a tubular network, suggesting a key regulatory role of hyaluronan in controlling TIME cell tubulogenesis in 3D matrices. Knock-down of CD44 resulted in an upregulation of mRNA expression of the chemokines CXCL9 and CXCL12, as well as their receptors CXCR3 and CXCR4. This was accompanied by a defect maturation of the tubular structure network and increased phosphorylation of the inhibitor of NFκB kinase (IKK) complex and thus translocation of NFκB into the nucleus and activation of chemokine targed genes. Furthermore, the interaction between CD44 and hyaluronan determines the adhesion of breast cancer cells. In summary, our observations support the notion that the interaction between CD44 and hyaluronan regulates microvascular endothelial cell tubulogenesis by affecting the expression of cytokines and their receptors, as well as breast cancer dissemination.

Low molecular weight hyaluronan activates cytosolic phospholipase A2α and eicosanoid production in monocytes and macrophages

Hyaluronan (HA) is the major glycosaminoglycan in the extracellular matrix. During inflammation, there is an increased breakdown of HA, resulting in the accumulation of low molecular weight (LMW) HA and activation of monocytes and macrophages. Eicosanoids, derived from the cytosolic phospholipase A2 group IVA (cPLA2α) activation, are potent lipid mediators also attributed to acute and chronic inflammation. The aim of this study was to determine the effect of LMW HA on cPLA2α activation, arachidonic acid (AA) release, and subsequent eicosanoid production and to examine the receptors and downstream mechanisms involved in these processes in monocytes and differently polarized macrophages. LMW HA was a potent stimulant of AA release in a time- and dose-dependent manner, induced cPLA2α, ERK1/2, p38, and JNK phosphorylation, as well as activated COX2 expression and prostaglandin (PG) E2 production in primary human monocytes, murine RAW 264.7, and wild-type bone marrow-derived macrophages. Specific cPLA2α inhibitor blocked HA-induced AA release and PGE2 production in all of these cells. Using CD44, TLR4, TLR2, MYD88, RHAMM or STAB2 siRNA-transfected macrophages and monocytes, we found that AA release, cPLA2α, ERK1/2, p38, and JNK phosphorylation, COX2 expression, and PGE2 production were activated by LMW HA through a TLR4/MYD88 pathway. Likewise, PGE2 production and COX2 expression were blocked in Tlr4(-/-) and Myd88(-/-) mice, but not in Cd44(-/-) mice, after LMW HA stimulation. Moreover, we demonstrated that LMW HA activated the M1 macrophage phenotype with the unique cPLA2α/COX2(high) and COX1/ALOX15/ALOX5/LTA4H(low) gene and PGE2/PGD2/15-HETE(high) and LXA4(low) eicosanoid profile. These findings reveal a novel link between HA-mediated inflammation and lipid metabolism.

The AIN-76A defined rodent diet accelerates the development of heart failure in SHHF rats: a cautionary note on its use in cardiac studies

Previous studies from our laboratory have shown positive benefits of linoleic acid (LA) feeding for attenuation of rat heart failure (HF). However, another research group concluded LA feeding was detrimental to cardiac function, using the American Institute of Nutrition 76A (AIN) diet as a background diet for the experimental animals only. To reconcile these conflicting results and determine whether (i) AIN has effects on cardiovascular function, and (ii) AIN reverses the positive effects of LA feeding, studies were performed using spontaneously hypertensive heart failure (SHHF) rats in both a survival study with lifetime feeding of AIN (control: Purina 5001) and a 2 × 2 factorial design for 6 weeks in young male SHHF rats with background diet and LA as variables. During a lifetime of AIN feeding, mortality from heart failure is significantly accelerated, cardiolipin altered and triglycerides increased. In young rats, 6 weeks on the AIN diet promoted increased systolic and diastolic blood pressure, increased fed and fasting blood glucose, increased serum inflammatory eicosanoids, decreased docosahexanoic acid, increased posterior wall thickness in diastole and an altered cardiolipin subspecies profile. The addition of LA to the AIN diet was able to rescue blood pressure. However, the combination increased retroperitoneal fat mass, body weight and fed blood glucose beyond the levels with the AIN diet alone. Because the AIN diet has wide ranging effects on cardiovascular parameters, our results suggest that it should not be used in animal studies involving the cardiovascular system unless induction of cardiac dysfunction is the desired outcome.

Role of hyaluronan in angiogenesis and its utility to angiogenic tissue engineering

Angiogenesis represents the outgrowth of new blood vessels from existing ones, a physiologic process that is vital to supply nourishment to newly forming tissues during development and tissue remodeling and repair (wound healing). Regulation of angiogenesis in the healthy body occurs through a fine balance of angiogenesis-stimulating factors and angiogenesis inhibitors. When this balance is disturbed, excessive or deficient angiogenesis can result and contribute to development of a wide variety of pathological conditions. The therapeutic stimulation or suppression of angiogenesis could be the key to abrogating these diseases. In recent years, tissue engineering has emerged as a promising technology for regenerating tissues or organs that are diseased beyond repair. Among the critical challenges that deter the practical realization of the vision of regenerating functional tissues for clinical implantation, is how tissues of finite size can be regenerated and maintained viable in the long-term. Since the diffusion of nutrients and essential gases to cells, and removal of metabolic wastes is typically limited to a depth of 150-250 microm from a capillary (3-10 cells thick), tissue constructs must mandatorily permit in-growth of a blood capillary network to nourish and sustain the viability of cells within. The purpose of this article is to provide an overview of the role and significance of hyaluronan (HA), a glycosaminoglycan (GAG) component of connective tissues, in physiologic and pathological angiogenesis, its applicability as a therapeutic to stimulate or suppress angiogenesis in situ within necrotic tissues in vivo, and the factors determining its potential utility as a pro-angiogenic stimulus that will enable tissue engineering of neo-vascularized and functional tissue constructs for clinical use.

Acute Lung Injury Regulation by Hyaluronan

Acute lung injury (ALI) and its more severe form, acute respiratory distress syndrome (ARDS), have high mortality rates with few treatment options. An important regulatory factor in the pathology observed in ALI/ARDS is a disruption of the pulmonary endothelial barrier which, in combination with epithelial barrier disruption, causes leakage of fluid, protein and cells into lung airspaces. Degradation of the glycosaminoglycan, hyaluronan (HA), is involved in reduction of the endothelial glycocalyx, disruption of endothelial cell-cell contacts and activation of HA binding proteins upregulated in ALI/ARDS which promote a loss of pulmonary vascular integrity. In contrast, exogenous administration of high molecular weight HA has been shown to be protective in several models of ALI. This review focuses on the dichotomous role of HA to both promote and inhibit ALI based on its size and the HA binding proteins present. Further, potential therapeutic applications of high molecular weight HA in treating ALI/ARDS are discussed.

Prognostic significance of CD44s expression in resected non-small cell lung cancer

Background

CD44s is a cell adhesion molecule known to mediate cellular adhesion to the extracellular matrix, a prerequisite for tumor cell migration. CD44s plays an important role in invasion and metastasis of various cancers. In the present study, we sought to determine whether CD44s is involved in clinical outcomes of patients with resected non-small cell lung cancer (NSCLC).

Methods

Using immunohistochemical staining, we investigated CD44s protein expression using tissue array specimens from 159 patients with resected NSCLC (adenocarcinoma (AC; n = 82) and squamous cell carcinoma (SCC; n = 77). Additionally, the immunoreactivity of cyclooxygenase (COX)-2 was also studied. The clinicopathological implications of these molecules were analyzed statistically.

Results

High CD44s expression was detected more frequently in NSCLC patients with SCC (66/72; 91.7%) than in those with AC histology (P <0.001). Additionally, high CD44s expression was significant correlated with more advanced regional lymph node metastasis (P = 0.021). In multivariate analysis of survival in NSCLC patients with AC histology, significant predictors were lymph node metastasis status (P < 0.001), high-grade tumor differentiation (P = 0.046), and high CD44s expression (P = 0.014). For NSCLC patients with SCC histology, the significant predictor was a more advanced tumor stage (P = 0.015). No significant association was found between CD44s and clinical outcome (P = 0.311).

Conclusions

High CD44s expression was a negative prognostic marker with significance in patients with resected NSCLC, particularly those with AC histology, and was independent of tumor stage.

Clinicopathologic correlation of cancer stem cell markers CD44, CD24, VEGF and HIF-1α in ductal carcinoma in situ and invasive ductal carcinoma of breast: an immunohistochemistry-based pilot study

CD24(-/low)CD44(+) cells have been identified as putative cancer stem cells (CSCs) in breast cancer. However, the expression of these markers, as well as their association with clinical parameters or tumor microenvironment of breast cancer, remains largely unknown. In the present study, we examined the expression of CD44, CD24, VEGF, and HIF-1α in human breast tumor tissues and assessed their clinicopathological correlations. We investigated tissue samples, including 117 cases of invasive ductal carcinoma (IDCa), 14 cases of ductal carcinoma in situ (DCIS), and 15 cases of intraductal hyperplasia (IDH) from breast tissues. The expression of CD44, CD24, HIF-1α, and VEGF was evaluated using immunohistochemical staining. CD24, CD44, HIF-1α, and VEGF were expressed in 49 (41.9%), 51 (43.6%), 32 (27.4%), and 97 cases (82.9%), respectively, in IDCa. CD24(-/low)CD44(+) cells were noted in 48 (41.3%) cases. The levels of CD24 and VEGF expression correlated positively with tumor malignancy (P<0.05). Meanwhile, the expression of CD24, CD44, and VEGF correlated significantly positively with increasing tumor grade (P<0.05). In addition, associations between CD44 and VEGF, CD24 and VEGF, HIF-1α and VEGF, CD24(-/low)CD44(+) and VEGF, CD24(-/low)CD44(+) and HIF-1α were also observed (P<0.05). The HIF-1α expression level was relatively higher in early stage breast cancer patients with CD24(-/low)CD44(+) cells. Taken together, our results suggest that CD24 and VEGF may play important roles in breast tumorigenesis and progression, while HIF-1α may play a role in the early stage of breast carcinogenesis.

Integrin-mediated adhesion and proliferation of human MSCs elicited by a hydroxyproline-lacking, collagen-like peptide

In this study, we evaluated the competence of a rationally designed collagen-like peptide (CLP-Cys) sequence - containing the minimal essential Glycine-Glutamic acid-Arginine (GER) triplet but lacking the hydroxyproline residue - for supporting human mesenchymal stem cell (hMSC) adhesion, spreading and proliferation. Cellular responses to the CLP-Cys sequence were analyzed by conjugating the peptide to two different substrates - a hard, planar glass surface and a soft hyaluronic acid (HA) particle-based hydrogel. Integrin-mediated cell spreading and adhesion were observed for hMSCs cultivated on the CLP-Cys functionalized surfaces, whereas on control surfaces lacking the peptide motif, cells either did not adhere or maintained a round morphology. On the glass surface, CLP-Cys-mediated spreading led to the formation of extended and well developed stress fibers composed of F-actin bundles and focal adhesion complexes while on the soft gel surface, less cytoskeletal reorganization organization was observed. The hMSCs proliferated significantly on the surfaces presenting CLP-Cys, compared to the control surfaces lacking CLP-Cys. Competitive binding assay employing soluble CLP-Cys revealed a dose-dependent inhibition of hMSC adhesion to the CLP-Cys-presenting surfaces. Blocking the α(2)β(1) receptor on hMSC also resulted in a reduction of cell adhesion on both types of CLP-Cys surfaces, confirming the affinity of CLP-Cys to α(2)β(1) receptors. These results established the competence of the hydroxyproline-free CLP-Cys for eliciting integrin-mediated cellular responses including adhesion, spreading and proliferation. Thus, CLP-Cys-modified HA hydrogels are attractive candidates as bioactive scaffolds for tissue engineering applications.

Role of hyaluronan and hyaluronan-binding proteins in lung pathobiology

Hyaluronan (HA) has diverse functions in normal lung homeostasis and pulmonary disease. HA constitutes the major glycosaminoglycan in lung tissue, with HA degradation products, produced by hyaluronidase enzymes and reactive oxygen species, being implicated in several lung diseases, including acute lung injury, asthma, chronic obstructive pulmonary disease, and pulmonary hypertension. The differential activities of HA and its degradation products are due, in part, to regulation of multiple HA-binding proteins, including cluster of differentiation 44 (CD44), Toll-like receptor 4 (TLR4), HA-binding protein 2 (HABP2), and receptor for HA-mediated motility (RHAMM). Recent research indicates that exogenous administration of high-molecular-weight HA can serve as a novel therapeutic intervention for lung diseases, including lipopolysaccharide (LPS)-induced acute lung injury, sepsis/ventilator-induced lung injury, and airway hyperreactivity. This review focuses on the regulatory role of HA and HA-binding proteins in lung pathology and discusses the capacity of HA to augment and inhibit various lung diseases.

Vasculopathy in type 2 diabetes mellitus: role of specific angiogenic modulators

Type 2 diabetes mellitus (T2DM) is largely defined by hyperglycemia that promotes vascular complications. Abnormal angiogenesis has been claimed to have a role in this disease. This study aimed to investigate serum levels of both conventional and other markers of angiogenesis not well studied before in diabetes, and to correlate findings with age of the patients, glycemic control, presence of microvascular complications, and oxidative stress. Thirty-eight patients with T2DM and 13 age- and sex-matched healthy persons representing controls were recruited. Serum levels of basic fibroblast growth factor (b-FGF) was measured by immunosorbent assay kit; advanced glycosylation end products, platelet-derived endothelial cell growth factor (PD-ECGF), cathepsin-D (CD), gangliosides, hyaluronic acid (HA), nitric oxide (NO), lipid peroxides (LPER), superoxide dismutase, and total thiols by chemical methods; and copper (Cu) by atomic absorption flame photometry. Advanced glycosylation end products and angiogenic factors (b-FGF, PD-ECGF, CD, gangliosides, HA, and Cu) were significantly higher in patients than controls. Oxidative stress markers, NO, and LPER were significantly higher while total thiols were significantly lower in patients than controls. These changes were more pronounced with age, poor glycemic control, and presence of microvascular complications. Angiogenesis dysfunction coinciding with elevated levels of many angiogenic growth factors may point to their malfunctioning due to oxidative stress and/or protein glycation at the factor and the receptor levels. This necessitates further investigations.

Application of resorbable poly(lactide-co-glycolide) with entangled hyaluronic acid as an autograft extender for posterolateral intertransverse lumbar fusion in rabbits

Facilitating fusion between bony segments in a reliable and reproducible manner using a synthetic bone graft material has a number of benefits for the surgeon as well as the patient. Although autograft remains the gold standard, associated comorbidities continue to drive the development of new biomaterials for use in spinal fusion. The ability of autograft alone and autograft combined with a radiolucent biomaterial composed of resorbable osteoconductive poly(lactide-co-glycolide) with entangled hyaluronic acid to facilitate fusion was examined in a single-level noninstrumented posterolateral intertransverse lumbar fusion model in New Zealand White rabbits. Progressive bone formation was demonstrated radiographically for the extender group (synthetic biomaterial plus autograft) between 3 and 6 months. Computed tomography revealed a new cortical shell in the fusion mass at 3 and 6 months for both study groups. Tensile testing at 6 months demonstrated that the quality of bone formed between the intertransverse space was equivalent for both study groups. Histologic evaluation of the fusion mass revealed new bone on and adjacent to the transverse processes with the synthetic biomaterial group that extended laterally, supporting the osteoconductive nature of the material. Histological evidence of endochondral bone growth in the intertransverse space was observed for the autograft plus synthetic biomaterial group. Bone remodeling, new marrow spaces, and peripheral cortices were observed for each study group at 3 months that matured by 6 months. These findings support the use of a radiolucent biosynthetic material comprising poly(lactide-co-glycolide) with integrated hyaluronic acid as an autograft extender for lumbar intertransverse fusion.

Brain sweet brain: importance of sugars for the cerebral microenvironment and tumor development

The extracellular matrix (ECM) in the brain tissue is a complex network of glycoproteins and proteoglycans that fills the intercellular space serving as scaffolding to provide structural framework for the tissue and regulate the behavior of cells via specific receptors - integrins. There is enormous structural diversity among proteoglycans due to variation in the core protein, the number of glycosaminoglycans chains, the extent and position of sulfation. The lectican family of proteoglycans interacts with growth factors, hyaluronan and tenascin forming a complex structure that regulates neuronal plasticity and ion homeostasis around highly active neurons. In this review, we will discuss the latest insights into the roles of brain glycoproteins as modulators of cell adhesion, migration, neurite outgrowth and glial tumor invasion.

Inhibition of cell proliferation by CD44: Akt is inactivated and EGR-1 is down-regulated

OBJECTIVE

CD44 is a transmembrane glycoprotein and can facilitate signal transduction by serving as a platform for molecular recruitment and assembly. A number of studies have suggested that CD44 can either positively or negatively regulate cell proliferation. The purpose of this study was to investigate how CD44 can inhibit cell proliferation.

MATERIALS AND METHODS

We engineered E6.1 Jurkat cells to express CD44. Importantly, these cells lack endogenous CD44 expression. Molecular pathways involved with cell proliferation were studied using RT(2)-PCR array, siRNA, Western blotting and by employing pharmacological inhibitors of ERK1/2, p38 and the PI3K/Akt pathways.

RESULTS

We found that CD44 expression significantly inhibited cell proliferation and down-regulated EGR-1 expression and EGR-1 targets cyclin D1 and cyclin D2. Transfection of control E6.1 Jurkat cells with EGR-1 siRNA also inhibited cell proliferation, confirming its role. Disruption of the PI3K/Akt pathway with pharmacological inhibitors reduced both EGR-1 expression and cell proliferation, recapitulating the properties of CD44 expressing cells. Akt was hypophosphorylated in cells expressing CD44 showing its potential role in negatively regulating Akt activation. Strikingly, constitutively active Akt rescued the proliferation defect showing requirement for active Akt, in our system.

CONCLUSION

Our results suggest a novel pathway by which CD44 inactivates Akt, down-regulates EGR-1 expression and inhibits cell proliferation.

Vascular endothelial growth factor and not cyclooxygenase 2 promotes endothelial cell viability in the pancreatic tumor microenvironment

OBJECTIVES

Cyclooxygenase 2 (COX-2) and vascular endothelial growth factor (VEGF), often coexpressed in cancer, are associated with poor prognosis. However, results from pancreatic cancer trials of their inhibitors were disappointing. This study delineated the role of COX-2 and nonsteroidal anti-inflammatory drugs in angiogenesis and VEGF regulation.

METHODS

AsPC-1 and BxPC-3 pancreatic cancer cells were cocultured with human umbilical vein endothelial cells (HUVECs). NS398 or VEGF-neutralizing antibody was added, and HUVEC viability assayed. Prostaglandin E2 and VEGF were quantified. Tumor cells were treated with NS398 or celecoxib, and VEGF quantified.

RESULTS

In cocultures, HUVEC viability in AsPC-1 was 60% that of BxPC-3 controls (P < 0.05). Prostaglandin E2 and VEGF from BxPC-3 were double that of AsPC-1 (P < 0.05). NS398 reduced prostaglandin E2 to undetectable levels (P < 0.05) but had no effect on HUVEC viability. Vascular endothelial growth factor-neutralizing antibody reduced HUVEC viability in BxPC-3 wells to that of AsPC-1 (P < 0.05). NS398 had no effect on VEGF. Celecoxib increased VEGF in a concentration-dependent manner in each cell line up to 4-fold (P < 0.05).

CONCLUSIONS

Cyclooxygenase 2 does not regulate VEGF in pancreatic cancer, and celecoxib upregulates VEGF in pancreatic cancer. It is VEGF, and not COX-2, inhibitors that reduce tumor-stimulated endothelial cell viability. Future pancreatic cancer trials should consider lower-dose nonsteroidal anti-inflammatory drugs in combination with VEGF inhibitors.

COX-2, VEGF and tumour angiogenesis

Epidemiological evidence suggests a protective effective of regular NSAID use against developing cancer. Cyclooxygenase-2, a target of NSAIDs, is upregulated in many cancers and has been associated with increased VEGF production and angiogenesis. Angiogenesis is the formation of new vessels from existing vasculature and as an essential process for tumour development represents an important therapeutic target. Following an extensive review of the literature this article details the current knowledge on the role of COX-2 in tumorigenesis focusing on its relationship to angiogenesis and VEGF production by tumour cells. While COX-2 is clearly detrimental to prognosis and NSAIDs have a beneficial effect, the possibility of COX-2 independent effects being partly or wholly responsible for this benefit cannot be excluded.

Anti-inflammatory effects of hyaluronan in arthritis therapy: Not just for viscosity

Hyaluronic acid (HA) has been widely used for viscosupplementation of diseased or aged articular joints. However, recent investigations have revealed the active anti-inflammatory or chondroprotective effect of HA, suggesting its potential role in attenuation of joint damage. In particular, interactions between HA and other inflammatory mediators are attracting interest. This review summarizes several aspects of recent investigations of the anti-inflammatory effects of HA in arthritis.

Hyaluronan constitutively regulates activation of COX-2-mediated cell survival activity in intestinal epithelial and colon carcinoma cells

Hyaluronan is a major component of the pericellular matrix surrounding tumor cells, including colon carcinomas. Elevated cycooxygenase-2 levels have been implicated in several malignant properties of colon cancer. We now show for the first time a strong link between hyaluronan-CD44 interaction and cyclooxygenase-2 in colon cancer cells. First, we have shown that increased expression of hyaluronan synthase-2 induces malignant cell properties, including increased proliferation, anchorage-independent growth, and epithelial-mesenchymal transition in HIEC6 cells. Second, constitutive hyaluronan-CD44 interaction stimulates a signaling pathway involving ErbB2, phosphoinositide 3-kinase/AKT, beta-catenin, and cyclooxygenase-2/prostaglandin E(2) in HCA7 colon carcinoma cells. Third, the HA/CD44-activated ErbB2 --> phosphoinositide 3-kinase/AKT --> beta-catenin pathway stimulates cell survival/cell proliferation through COX-2 induction in hyaluronan-overexpressing HIEC6 cells and in HCA7 cells. Fourth, perturbation of hyaluronan-CD44 interaction by hyaluronan oligomers or CD44-silencing RNA decreases cyclooxygenase-2 expression and enzyme activity, and inhibition of cyclooxygenase-2 decreases hyaluronan production suggesting the possibility of an amplifying positive feedback loop between hyaluronan and cyclooxygenase-2. We conclude that hyaluronan is an important endogenous regulator of colon cancer cell survival properties and that cyclooxygenase-2 is a major mediator of these hyaluronan-induced effects. Defining hyaluronan-dependent cyclooxygenase-2/prostaglandin E(2)-associated signaling pathways will provide a platform for developing novel therapeutic approaches for colon cancer.

COX-2 and CCR2 induced by CD40 ligand and MCP-1 are linked to VEGF production in endothelial cells

Recent studies have reported that expression of MCP-1 and its receptor, CCR2; and CD40-CD40 ligand (CD40L) interaction on mesenchymal cells play important roles in tumor development. Studies have also connected MCP-1, CCR2, and CD40L to COX-2 expression. The aim of this study was to examine the effect of MCP-1/CCR2 and CD40-CD40L interaction on COX-2 and VEGF expression in endothelial cells. We also investigated the localization of these proteins in gastric cancer tissue. COX-2 and CCR2 levels were evaluated in CD40L-stimulated HUVECs by Western blot and real-time PCR. VEGF secreted in the culture media was quantified by ELISA. Localizations of MCP-1, CD40L, CD34, CD40 and CCR2 in 34 gastric cancer tissue specimens were evaluated by immunohistochemistry. CD40-CD40L interaction-induced COX-2 production and subsequently, upregulated COX-2 production contributed to elevated VEGF and CCR2 levels in CD40L-stimulated HUVECs. CD40L-stimulated VEGF production was COX-2 but not COX-1 dependent. RS-102895, a CCR2-specific antagonist, significantly reduced VEGF production in CD40L- and MCP-1-stimulated HUVECs. MCP-1 had a synergistic effect on COX-2, CCR2 and VEGF levels in CD40L-stimulated HUVECs. In gastric cancer tissue, there was significant correlation between microvessel density and scores for CD40L, MCP-1 and CCR2 protein expression. Thus, MCP-1 had a synergistic effect on COX-2 and CCR2 protein expression in CD40L-stimulated HUVECs and thereby stimulated VEGF production in these cells.

OPN/CD44v6 overexpression in laryngeal dysplasia and correlation with clinical outcome

Laryngeal dysplasia is a common clinical concern. Despite major advancements, a significant number of patients with this condition progress to invasive squamous cell carcinoma. Osteopontin (OPN) is a secreted glycoprotein, whose expression is markedly elevated in several types of cancers. We explored OPN as a candidate biomarker for laryngeal dysplasia. To this aim, we examined OPN expression in 82 cases of dysplasia and in hyperplastic and normal tissue samples. OPN expression was elevated in all severe dysplasia samples, but not hyperplastic samples, with respect to matched normal mucosa. OPN expression levels correlated positively with degree of dysplasia (P=0.0094) and negatively with disease-free survival (P<0.0001). OPN expression was paralleled by cell surface reactivity for CD44v6, an OPN functional receptor. CD44v6 expression correlated negatively with disease-free survival, as well (P=0.0007). Taken as a whole, our finding identify OPN and CD44v6 as predictive markers of recurrence or aggressiveness in laryngeal intraepithelial neoplasia, and overall, point out an important signalling complex in the evolution of laryngeal dysplasia.

Aqueous humor sCD44 concentration and visual field loss in primary open-angle glaucoma

PURPOSE

To correlate aqueous humor soluble CD44 (sCD44) concentration, visual field loss, and glaucoma risk factors in primary open-angle glaucoma (POAG) patients.

METHODS

Aqueous samples were obtained by paracentesis from normal and glaucoma patients who were undergoing elective surgery and analyzed for sCD44 concentration by enzyme-linked immunosorbent assay.

RESULTS

In normal aqueous (n=124) the sCD44 concentration was 5.88+/-0.27 ng/mL, whereas in POAG aqueous (n=90) the sCD44 concentration was 12.76+/-0.66 ng/mL, a 2.2-fold increase (P<0.000001). In POAG patients with prior successful filtration surgery (n=13), the sCD44 concentration was decreased by 43% to 7.32+/-1.44 (P=0.001) in comparison with POAG patients without filtration surgery; however, the sCD44 concentration in the prior successful filtration subgroup with no medications and normal intraocular pressure was 12.62+/-3.81 (P=0.05) compared with normal. The sCD44 concentration of normal pressure glaucoma patients was 9.19+/-1.75 ng/mL, a 1.6-fold increase compared with normal (P=0.02). Race and intraocular pressure pulse amplitude were significant POAG risk factors in this cohort of patients. In both normal and POAG patients with mild and moderate visual field loss, sCD44 concentration was greater in African Americans than in whites (P=0.04).

CONCLUSIONS

sCD44 concentration in the aqueous of POAG patients correlated with the severity of visual field loss in all stages in white patients and in mild to moderate stages in African American patients. sCD44 concentration in aqueous is a possible protein biomarker of visual field loss in POAG.