Expression of hyaluronate and hyaluronate synthase in human primary tumours and their metastases in scid mice

On-site delivery of bioactive nanospheres utilizing lanthanides as crosslinkers and metastasis-inhibiting agents for breast cancer therapy

Postoperative breast cancer patients face a critical 2-3-week window during which residual tumor cells are highly prone to metastasis, yet systemic therapies are often ineffective due to impaired vascularization and limited drug transport. To address this challenge, we developed an injectable nanosphere formulation based on hyaluronic acid (HyA) crosslinked with lanthanide ions-europium (Eu) or lanthanum (La) ions-that act dually as physical crosslinkers and therapeutic agents. This dual-function design ensures structural stability without chemical crosslinkers, while actively inhibiting cancer cell migration, invasion, and colonization. The small ionic size of lanthanides facilitates deep interstitial transport, overcoming diffusion barriers in poorly perfused tissues. Upon injection, the nanospheres swell to sub-micrometer dimensions, achieving prolonged retention at the tumor site and sustained ion release for up to 21 days. In vitro and in vivo studies revealed distinct anti-metastatic profiles: HyA-Eu nanospheres effectively suppressed migration and distant metastasis, whereas HyA-La nanospheres inhibited colony formation and primary tumor growth. These results demonstrate a novel lanthanide ion-mediated strategy for post-surgical cancer therapy, integrating local retention with controlled ion release to bridge the treatment gap during recovery.

Recovery of ΔF508-CFTR Function by Citrate

Treatment of cystic fibrosis relies so far on expensive and sophisticated drugs. A logical approach to rescuing the defective ΔF508-CFTR protein has not yet been published. Therefore, virtual docking of ATP and CFTR activators to the open conformation of the CFTR protein was performed. A new ATP binding site outside of the two known locations was identified. It was located in the cleft between the nucleotide binding domains NBD1 and NBD2 and comprised six basic amino acids in close proximity. Citrate and isocitrate were also bound to this site. Citrate was evaluated for its action on epithelial cells with intact CFTR and defective ΔF508-CFTR. It activated hyaluronan export from human breast carcinoma cells and iodide efflux, and recovered ΔF508-CFTR from premature intracellular degradation. In conclusion, citrate is an activator for ΔF508-CFTR and increases export by defective ΔF508-CFTR into the extracellular matrix of epithelial cells.

Inhibition of Angiogenesis and Extracellular Matrix Remodeling: Synergistic Effect of Renin-Angiotensin System Inhibitors and Bevacizumab

Bevacizumab (Bev) is a humanized vascular endothelial growth factor monoclonal antibody that is used with chemotherapeutic drugs for the treatment of metastatic colorectal cancer (mCRC). Bev-induced hypertension (HT) is the most common adverse reaction during clinical practice. However, at present, appropriate antihypertensive agents for Bev-induced HT are unavailable. In this study, retrospective analysis of clinical data from mCRC patients who received renin-angiotensin system inhibitors (RASIs) showed significant survival benefits of overall survival (OS) and progression-free survival (PFS) over patients who received calcium channel blockers (CCBs) and patients who received no antihypertensive drug (NO: Y2020046 retrospectively registered). An experiment of HCT116 colon cancer cell xenografts in mice confirmed that combined treatment of Bev and lisinopril (Lis), a RASI, synergistically inhibited subcutaneous tumor growth and enhanced the concentration of 5-fluorouracil (5-Fu) in tumor tissues. Our results showed that the addition of Lis did not interfere with the vascular normalization effect promoted by Bev, but also inhibited collagen and hyaluronic acid (HA) deposition and significantly downregulated the expression of TGF-β1 and downstream SMAD signaling components which were enhanced by Bev, ultimately remodeling primary extracellular matrix components. In conclusion, RASIs and Bev have synergistic effect in the treatment of colorectal cancer and RASIs might be an optimal choice for the treatment of Bev-induced HT.

The hyaluronan-related genes HAS2, HYAL1-4, PH20 and HYALP1 are associated with prognosis, cell viability and spheroid formation capacity in ovarian cancer

Purpose

Hyaluronan modulates tumour progression, including cell adhesion, cohesion, proliferation and invasion, and the cancer stem cell phenotype. In ovarian cancer, high levels of stromal hyaluronan are associated with poor prognosis. In this work, hyaluronan synthases (HAS1-3) and hyaluronidases (HYAL1-4, PH-20, HYALP1) were examined with regard to different levels of gene expression and its influence on ovarian cancer patients’ survival. The impact of a siRNA depletion of HAS2 was investigated in vitro.

Methods

Using the Kaplan–Meier Plotter tool, we investigated the influence of hyaluronic synthases and hyaluronidases on the survival of a collective of 1435 ovarian cancer patients. Differences in gene expression between normal (n = 46) and cancerous (n = 744) ovarian tissue were examined using the TNMplot database. Following an evaluation of hyaluronan-related gene expression in the ATCC ovarian cancer panel, we studied SKOV3 and SW 626 ovarian cancer cells subjected to HAS2 siRNA or control siRNA treatment in terms of HAS1-3, HYAL2 and HYAL3 mRNA expression. We investigated the ability to form spheroids using the Hanging Drop method and the response to chemotherapy at different concentrations using the MTT Assay. By STRING analysis, interactions within the enzymes of the hyaluronic acid system and with binding partners were visualized.

Results

HAS1, HYAL1 and HYAL4 mRNA expression is significantly upregulated, whereas HAS2, HYAL2 and HYAL3 mRNA expression is significantly downregulated in ovarian cancer tissue compared to controls. HAS2 improves cell viability, the capability to form tumour spheroids and has a negative prognostic value regarding overall survival. Lower HAS2 expression and high expression of HYAL2 and HYAL3 favours the survival of ovarian cancer patients. HAS2 knockdown cells and control cells showed a moderate response to combinatorial in vitro chemotherapy with taxol and cisplatin.

Conclusion

In conclusion, our study shows that the hyaluronic acid system has a relevant influence on the survival of ovarian cancer patients and could therefore be considered as a possible prognostic factor.

Effect of Ultrasound Combined With Microbubble Therapy on Interstitial Fluid Pressure and VX2 Tumor Structure in Rabbit

Interstitial fluid pressure (IFP) in tumor tissue is significantly higher than that in normal tissue, which reduces the effectiveness of therapeutic drugs. There are several methods to decrease the IFP, such as normalizing blood vessel, decreasing hyaluronic acid and collagen fiber content in the extracellular matrix (ECM), and recovering lymphatic function. Reducing tumor IFP might be developed as a novel approach in cancer therapy. In this study, we aimed to elucidate the relationship between ultrasound combined with microbubble therapy and IFP, and the associated mechanism. VX2 tumor in rabbit was treated with ultrasound combined with microbubbles at different intensities. The IFP was measured using the wick-in-needle (WIN) method. The collagen and reticular fibers were stained by Masson and Gordon-Sweets, respectively. The results showed that low-frequency non-focus ultrasound combined with microbubbles therapy influences the IFP in tumor tissues; low-frequency non-focus ultrasound with low pressure increased the IFP, whereas middle-high pressure decreased the IFP. The results showed that the structure and content of collagen and reticular fibers in tumor tissue were rarely influenced by the treatment. Our study provides a novel approach of reduced IFP antitumor therapy.

Smart Cell-Penetrating Peptide-Based Techniques for Intracellular Delivery of Therapeutic Macromolecules

Many therapeutic macromolecules must enter cells to take their action. However, their treatment outcomes are often hampered by their poor transportation into target cells. Therefore, efficient intracellular delivery of these macromolecules is critical for improving their therapeutic efficacy. Cell-penetrating peptide (CPP)-based approaches are one of the most efficient methods for intracellular delivery of macromolecular therapeutics. Nevertheless, poor specificity is a significant concern for systemic administrated CPP-based delivery systems. This chapter will review recent advances in CPP-mediated macromolecule delivery with a focus on various smart strategies which not only enhance the intracellular delivery but also improve the targeting specificity.

Hyaluronic acid in digestive cancers

PURPOSE

Hyaluronan (HA), an extracellular and peri-cellular glycosaminoglycan with a large molecular weight, plays an important role in cancer growth and metastasis. The aim of this study was to summarize the biological roles and regulation of HA and small HA fragments, and their metabolismn enzymes and receptors in human digestive cancers.

METHODS

A systematic literature search mainly focusing on the biological roles of HA in the development and progression of human digestive cancers was performed using electronic databases.

RESULTS

The correlation between HA accumulation and tumor progression has been shown in various digestive cancers. HA and HA fragment-tumor cell interaction could activate the downstream signaling pathways, promoting cell proliferation, adhesion, migration and invasion, and inducing angiogenesis, lymphangiogenesis, epithelial-mesenchymal transition, stem cell-like property, and chemoradioresistance in digestive cancers.

CONCLUSIONS

A better insight into the mechanism of HA and HA fragment involvement in digestive cancer progression might be useful for the development of novel biomarkers and therapeutic strategies.

The motile breast cancer phenotype roles of proteoglycans/glycosaminoglycans

The consecutive stages of cancer growth and dissemination are obligatorily perpetrated through specific interactions of the tumor cells with their microenvironment. Importantly, cell-associated and tumor microenvironment glycosaminoglycans (GAGs)/proteoglycan (PG) content and distribution are markedly altered during tumor pathogenesis and progression. GAGs and PGs perform multiple functions in specific stages of the metastatic cascade due to their defined structure and ability to interact with both ligands and receptors regulating cancer pathogenesis. Thus, GAGs/PGs may modulate downstream signaling of key cellular mediators including insulin growth factor receptor (IGFR), epidermal growth factor receptor (EGFR), estrogen receptors (ERs), or Wnt members. In the present review we will focus on breast cancer motility in correlation with their GAG/PG content and critically discuss mechanisms involved. Furthermore, new approaches involving GAGs/PGs as potential prognostic/diagnostic markers or as therapeutic agents for cancer-related pathologies are being proposed.

Chemotherapy-induced hyaluronan production: a novel chemoresistance mechanism in ovarian cancer

Background

Hyaluronan (HA) an important component of the extracellular matrix, has been linked to tumor progression and drug resistance in several malignancies. However, limited data is available for ovarian cancer. This study investigated the role of hyaluronan (HA) and a potential link between the HA-CD44 pathway and membrane ATP binding cassette (ABC) transporter proteins in ovarian cancer chemoresistance.

Methods

We investigated the ability of HA to block the cytotoxic effects of the chemotherapy drug carboplatin, and to regulate the expression of ABC transporters in ovarian cancer cells. We also examined HA serum levels in ovarian cancer patients prior to and following chemotherapy and assessed its prognostic relevance.

Results

HA increased the survival of carboplatin treated ovarian cancer cells expressing the HA receptor, CD44 (OVCAR-5 and OV-90). Carboplatin significantly increased expression of HAS2, HAS3 and ABCC2 and HA secretion in ovarian cancer cell conditioned media. Serum HA levels were significantly increased in patients following platinum based chemotherapy and at both 1st and 2nd recurrence when compared with HA levels prior to treatment. High serum HA levels (>50 μg/ml) prior to chemotherapy treatment were associated with significantly reduced progression-free (P = 0.014) and overall survival (P = 0.036). HA production in ovarian cancer cells was increased in cancer tissues collected following chemotherapy treatment and at recurrence. Furthermore HA treatment significantly increased the expression of ABC drug transporters (ABCB3, ABCC1, ABCC2, and ABCC3), but only in ovarian cancer cells expressing CD44. The effects of HA and carboplatin on ABC transporter expression in ovarian cancer cells could be abrogated by HA oligomer treatment. Importantly, HA oligomers increased the sensitivity of chemoresistant SKOV3 cells to carboplatin.

Conclusions

Our findings indicate that carboplatin chemotherapy induces HA production which can contribute to chemoresistance by regulating ABC transporter expression. The HA-CD44 signaling pathway is therefore a promising target in platinum resistant ovarian cancer.

Cross-talk between estradiol receptor and EGFR/IGF-IR signaling pathways in estrogen-responsive breast cancers: focus on the role and impact of proteoglycans

In hormone-dependent breast cancer, estrogen receptors are the principal signaling molecules that regulate several cell functions either by the genomic pathway acting directly as transcription factors in the nucleus or by the non-genomic pathway interacting with other receptors and their adjacent pathways like EGFR/IGFR. It is well established in literature that EGFR and IGFR signaling pathways promote cell proliferation and differentiation. Moreover, recent data indicate the cross-talk between ERs and EGFR/IGFR signaling pathways causing a transformation of cell functions as well as deregulation on normal expression pattern of matrix molecules. Specifically, proteoglycans, a major category of extracellular matrix (ECM) and cell surface macromolecules, are modified during malignancy and cause alterations in cancer cell signaling, affecting eventually functional cell properties such as proliferation, adhesion and migration. The on-going strategies to block only one of the above signaling effectors result cancer cells to overcome such inactivation using alternative signaling pathways. In this article, we therefore review the underlying mechanisms in respect to the role of ERs and the involvement of cross-talk between ERs, IGFR and EGFR in breast cancer cell properties and expression of extracellular secreted and cell bound proteoglycans involved in cancer progression. Understanding such signaling pathways may help to establish new potential pharmacological targets in terms of using ECM molecules to design novel anticancer therapies.

The interaction between LYVE-1 with hyaluronan on the cell surface may play a role in the diversity of adhesion to cancer cells

Hyaluronan (HA), a simple disaccharide unit, can polymerize and is considered a primary component of the extracellular matrix, which has a wide range of biological functions. In recent years, HA was found on the surface of tumor cells. According to previous reports, differing HA content on the cell surface of tumor cells is closely related to lymph node metastases, but the mechanisms mediating this process remained unclear. This research intended to study the surface content of HA on tumor cells and analyze cell adhesive changes caused by the interaction between HA and its lymphatic endothelial receptor (LYVE-1). We screened and observed high HA content on HS-578T breast cells and low HA content on MCF-7 breast cells through particle exclusion, immunofluorescence and flow cytometry experiments. The expression of LYVE-1, the lymph-vessel specific HA receptor, was consistent with our previous report and enhanced the adhesion of HA^high-HS-578T cells to COS-7^LYVE-1(+) through HA in cell static adhesion and dynamic parallel plate flow chamber experiments. MCF-7 breast cells contain little HA on the surface; however, our results showed little adhesion difference between MCF-7 cells and COS-7^LYVE-1(+) and COS-7^LYVE-1(−) cells. Similar results were observed concerning the adhesion of HS-578T cells or MCF-7 cells to SVEC4-10 cells. Furthermore, we observed for the first time that the cell surface HA content of high transfer tumor cells was rich, and we visualized the cross-linking of HA cable structures, which may activate LYVE-1 on lymphatic endothelial cells, promoting tumor adhesion. In summary, high-low cell surface HA content of tumor cells through the interaction with LYVE-1 leads to adhesion differences.

Inverse expression of hyaluronidase 2 and hyaluronan synthases 1-3 is associated with reduced hyaluronan content in malignant cutaneous melanoma

Background

Hyaluronan is an extracellular matrix glycosaminoglycan involved in invasion, proliferation and metastasis of various types of carcinomas. In many cancers, aberrant hyaluronan expression implicates disease progression and metastatic potential. Melanoma is an aggressive skin cancer. The role of hyaluronan in melanoma progression including benign nevi and lymph node metastases has not been investigated earlier, nor the details of its synthesis and degradation.

Methods

The melanocytic and dysplastic nevi, in situ melanomas, superficially and deeply invasive melanomas and their lymph node metastases were analysed immunohistochemically for the amount of hyaluronan, its cell surface receptor CD44, hyaluronan synthases 1–3 and hyaluronidases 1–2.

Results

Hyaluronan content of tumoral cells in deeply invasive melanomas and metastatic lesions was clearly reduced compared to superficial melanomas or benign lesions. Furthermore, hyaluronan content in the stromal cells of benign nevi was higher than in the premalignant or malignant tumors. The immunopositivity of hyaluronidase 2 was significantly increased in the premalignant and malignant lesions indicating its specific role in the degradation of hyaluronan during tumor progression. Similarly, the expression of hyaluronan synthases 1–2 and CD44 receptor was decreased in the metastases compared to the primary melanomas.

Conclusions

These findings suggest that the reciprocal relationship between the degrading and synthesizing enzymes account for the alterations in hyaluronan content during the growth of melanoma. These results provide new information about hyaluronan metabolism in benign, premalignant and malignant melanocytic tumors of the skin.

Recovery of ΔF508-CFTR function by analogs of hyaluronan disaccharide

We recently discovered that hyaluronan was exported from fibroblasts by MRP5 and from epithelial cells by cystic fibrosis (CF) transmembrane conductance regulator (CFTR) that was known as a chloride channel. On this basis we developed membrane permeable analogs of hyaluronan disaccharide as new class of compounds to modify their efflux. We found substances that activated hyaluronan export from human breast cancer cells. The most active compound 2-(2-acetamido-3,5-dihydroxyphenoxy)-5-aminobenzoic acid (Hylout4) was tested for its influence on the activity of epithelial cells. It activated the ion efflux by normal and defective ΔF508-CFTR. It also enhanced the plasma membrane concentration of the ΔF508-CFTR protein and reduced the transepithelial resistance of epithelial cells. In human trials of healthy persons, it caused an opening of CFTR in the nasal epithelium. Thus compound Hylout4 is a corrector that recovered ΔF508-CFTR from intracellular degradation and activated its export function.

Regulation of cell volume by glycosaminoglycans

Cell volume is regulated by a delicate balance between ion distribution across the plasma membrane and the osmotic properties of intra- and extracellular components. Using a fluorescent calcein indicator, we analysed the effects of glycosaminoglycans on the cell volume of hyaluronan producing fibroblasts and hyaluronan deficient HEK cells over a time period of 30 h. Exogenous glycosaminoglycans induced cell blebbing after 2 min and swelling of fibroblasts to about 110% of untreated cell volume at low concentrations which decreased at higher concentrations. HEK cells did not show cell blebbing and responded by shrinking to 65% of untreated cell volume. Heparin induced swelling of both fibroblasts and HEK cells. Hyaluronidase treatment or inhibition of hyaluronan export led to cell shrinkage indicating that the hyaluronan coat maintained fibroblasts in a swollen state. These observations were explained by the combined action of the Donnan effect and molecular crowding.

Role of versican, hyaluronan and CD44 in ovarian cancer metastasis

There is increasing evidence to suggest that extracellular matrix (ECM) components play an active role in tumor progression and are an important determinant for the growth and progression of solid tumors. Tumor cells interfere with the normal programming of ECM biosynthesis and can extensively modify the structure and composition of the matrix. In ovarian cancer alterations in the extracellular environment are critical for tumor initiation and progression and intra-peritoneal dissemination. ECM molecules including versican and hyaluronan (HA) which interacts with the HA receptor, CD44, have been shown to play critical roles in ovarian cancer metastasis. This review focuses on versican, HA, and CD44 and their potential as therapeutic targets for ovarian cancer.

Perineuronal net formation and structure in aggrecan knockout mice

Perineuronal nets (PNNs) are specialized substructures of the neural extracellular matrix (ECM) which envelop the cell soma and proximal neurites of particular sets of neurons with apertures at sites of synaptic contact. Previous studies have shown that PNNs are enriched with chondroitin sulfate proteoglycans (CSPGs) and hyaluronan, however, a complete understanding of their precise molecular composition has been elusive. In addition, identifying which specific PNN components are critical to the formation of this structure has not been demonstrated. Previous work in our laboratory has demonstrated that the CSPG, aggrecan, is a key activity-dependent component of PNNs in vivo. In order to assess the contribution of aggrecan to PNN formation, we utilized cartilage matrix deficiency (cmd) mice, which lack aggrecan. Herein, we utilized an in vitro model, dissociated cortical culture, and an ex vivo model, organotypic slice culture, to specifically investigate the role aggrecan plays in PNN formation. Our work demonstrates that staining with the lectin, Wisteria floribunda agglutinin (WFA), considered a broad PNN marker, is eliminated in the absence of aggrecan, suggesting the loss of PNNs. However, in contrast, we found that the expression patterns of other PNN markers, including hyaluronan and proteoglycan link protein 1 (HAPLN1), tenascin-R, brevican, and hyaluronan are unaffected by the absence of aggrecan. Lastly, we determined that while all PNN components are bound to the surface in a hyaluronan-dependent manner, only HAPLN1 remains attached to the cell surface when neurons are treated with chondroitinase. These results suggest a different model for the molecular association of PNNs to the cell surface. Together our work has served to assess the contribution of aggrecan to PNN formation while providing key evidence concerning the molecular composition of PNNs in addition to determining how these components ultimately form PNNs.

Expression and Clinical Signification of Cytosolic Hyaluronan Levels in Invasive Breast Cancer

BACKGROUND

Hyaluronic acid (HA), a high-molecular weight glycosaminoglycan, has been considered to be involved in the growth and progression of malignant tumors in several experimental studies. The objective of this work was to evaluate the cytosolic HA content in breast cancer, its possible relationship with clinicopathological tumor parameters and steroid receptor status, as well as its potential prognostic significance.

METHODS

Cytosolic HA levels were examined by means of immunoradiometric techniques in 850 patients with invasive breast cancer. The mean follow-up period for these patients was 55.1 months.

RESULTS

Cytosolic HA levels ranged widely in tumors (4-59767 ng/mg protein; median: 4960). Statistical analysis showed that HA levels were significantly higher in younger patients (p=0.0001), as well as in premenopausal than in postmenopausal patients (p=0.001). HA levels were also significantly higher in ductal or lobular histological type than in other histological types (coloid, medullar or papillar types) (p=0.0001). Likewise, HA correlated significantly and positively with tumoral levels of PgR (r sub S: 0.11; p=0.001) in the all group of patients. In the subgroup of patients with ductal invasive type, HA levels were also significantly higher in well differentiated tumors and in diploid tumors. In addition, in this latter group of patients, HA levels in tumors correlated also positively and significantly with the either estrogen-inducible proteins: PgR (r sub S: 0.11; p=0.001), pS2 (r sub S: 0.117; p=0.008) and tPA (r sub S: 0.314; p=0.0001). On the other hand, significant association between HA intratumoral levels and relapse-free survival and overall survival in the overall group of patients was not found. However, high HA intratumoral levels were significantly associated with longer relapse-free survival in the subgroup of patients with ductal histological type tumors (p=0.01), as well as in those patients without any type of systemic adjuvant treatment (p=0.01).

CONCLUSIONS

Our results suggest that high intratumoral levels of HA may be associated with tumors of favorable evolution in certain subgroups of patients with breast cancer. Thus, HA may provide additional prognostic information to that given by other biochemical markers currently used in breast cancer.

The over-expression of HAS2, Hyal-2 and CD44 is implicated in the invasiveness of breast cancer

Within tumors there appears to be an intricate balance between hyaluronan (HA) synthesis and degradation where the invading edges display increased HA metabolism. The metabolism of HA has not been characterized in breast cancer cell lines; therefore, this study quantitatively identifies and characterizes the enzymes responsible for the synthesis and degradation of HA while correlating gene expression to cancer cell invasiveness and HA receptor status. In ten well-established breast cancer cell lines, the expression of the genes for each hyaluronan synthase (HAS) and hyaluronidase (Hyal) isoform was quantitated using real-time and reverse transcriptase polymerase chain reaction (PCR). The synthesis and degradation rates of hyaluronan were determined by ELISA, while quantitation of HA receptors, CD44 and RHAMM was performed by comparative Western blotting. The molecular weight of HA synthesized by each HAS isoform and the degradation products of each hyaluronidase were characterized by size exclusion chromatography. It was demonstrated that highly invasive cell lines preferentially expressed the HAS2 and Hyal-2 isoforms, while less invasive cells expressed HAS3 and Hyal-3. There was a correlation between elevated levels of HA synthesis, CD44 expression and cancer cell migration thereby highlighting the pivotal role that HA metabolism plays in the aggressive breast cancer phenotype.

The expression pattern of hyaluronan synthase during human tooth development

In previous studies, hyaluronan (HA) and its major cell surface receptor CD44 have been suggested to play an important role during tooth development. HA synthases (HASs) are the enzymes that polymerize hyaluronan. Data on the expression pattern of HASs during tooth development is lacking and the aim of the present study was to investigate the localisation of HAS by immunohistochemistry in human tooth germs from different developmental stages. The distribution pattern of HAS in the various tissues of the "bell stage" tooth primordia corresponded to that of hyaluronan in most locations: positive HAS immunoreactivity was observed in the dental lamina cells, inner- and outer-enamel epithelium. On the stellate reticulum cells, moderate HAS signal was observed, similar to the layers of the oral epithelium, where faint HAS immunoreactivity was detected. At the early phase of dental hard tissues mineralization, strong HAS immunoreactivity was detected in the odontoblasts and their processes, as well as in the secretory ameloblasts and their apical processes and also, the pulpal mesenchymal cells. The HAS signals observed in odontoblasts and ameloblasts gradually decreased with age. Our results demonstrate that hyaluronan synthesised locally by different dental cells and these results provide additional indirect support to the suggestion that HA may contribute both to the regulation of tooth morphogenesis and dental hard tissue formation.

Expression ofHYAL2 mRNA, hyaluronan and hyaluronidase in B-cell non-Hodgkin lymphoma: Relationship with tumor aggressiveness

Hyaluronidases and their substrate, hyaluronan (HA), were mainly explored in solid tumors but rarely in hematologic malignancies. While HA involvement was demonstrated in invasion and metastasis in most cases of solid tumors, the role of hyaluronidases in cancer progression remains controversial. One of the hyaluronidases, HYAL2, is suspected to be involved in the first step of HA degradation. In this work, HYAL2 mRNA, HA and total hyaluronidases expression were examined in lymphoma tissue extracts and correlated to the lymphoma subtype. Real-time RT-PCR was performed to evaluate HYAL2 mRNA. HA and hyaluronidase were assayed by enzyme-linked sorbent assay. Our results showed that HYAL2 mRNA expression was correlated to lymphoma diagnosis (p = 6 x 10(-3)) and was significantly lower in high-grade lymphoma, i.e., diffuse large B-cell diffuse lymphomas (DLBCLs). Several forms of hyaluronidase were detected by zymography and total hyaluronidase activity detected in tissue extracts was not significantly different according to tumor grade. HA levels also correlated to lymphoma subtype (p = 1 x 10(-5)) and were higher in DLBCLs. Moreover, HYAL2 mRNA and HA expressions were inversely correlated (p = 0.035). HYAL2 gene is localized on chromosome 3p21, which contains candidates tumor suppressor genes. Our results suggest that HYAL2 may have a prognostic significance in lymphomas and an antioncogenic activity. Conversely, HA overexpression in high-grade lymphomas is in favor of its involvement in tumor development and could provide a useful target for lymphoma therapy using HA-binding peptides.

Lactate-sensitive response elements in genes involved in hyaluronan catabolism

Tissue anoxia occurs early in wound healing. This is accompanied by production of lactate followed by increased hyaluronan and CD44 expression, suggesting a cause and effect relationship. Fibroblasts increased hyaluronan and CD44 when lactate was added to cultures. Increased deposition of hyaluronan correlates with greater turnover. In current models of hyaluronan catabolism, it is tethered to cell surfaces by CD44 in caveolin-enriched invaginations. It is cleaved to 20-kDa fragments by Hyal-2 on the plasma membrane, endocytosed, and delivered ultimately to lysosomes, and further digested by Hyal-1. Sequence analyses of promoter regions of genes for CD44, caveolin-1, Hyal-1, and -2 revealed multiple AP-1 and ets-1 response elements. To test their relevance, RNA from lactate-treated fibroblasts was analyzed by reverse transcriptase-polymerase chain reaction. Increased transcripts of c-fos, c-jun, c-ets, Hyal-1, -2, CD44, and caveolin-1 mRNAs were observed. We have thus identified lactate-activated genes important in the wound healing responses. Similar responses facilitating tumor progression, the Warburg effect, may share such mechanisms.

Hyaluronan: genetic insights into the complex biology of a simple polysaccharide

It is appropriate that this review should appear in a volume dedicated to Mert Bernfield. Much of my interest in the cell biology of the extracellular matrix, particularly during development, echoes Mert's pioneering studies. His kind but provocative questioning during meetings is especially missed. The glycosaminoglycan hyaluronan is ubiquitous, and is especially abundant during embryogenesis. Hydrated matrices rich in hyaluronan expand the extracellular space, facilitating cell migration. The viscoelastic properties of hyaluronan are also essential for proper function of cartilage and joints. Recent understanding of hyaluronan biology has benefited from the identification of genes encoding hyaluronan synthases and hyaluronidases, genetic analysis of the roles of hyaluronan during development, elucidation of the biochemical mechanisms of hyaluronan synthesis, and by studies of human genetics and tumors. This review focuses on recent studies utilizing hyaluronan-deficient, gene targeted mice with null alleles for the principal source of hyaluronan during mid-gestation, hyaluronan synthase-2 (has-2).