Heparanase regulates esophageal keratinocyte differentiation through nuclear translocation and heparan sulfate cleavage

Heparanase 2 (Hpa2)- a new player essential for pancreatic acinar cell differentiation

Heparanase 2 (Hpa2, HPSE2) is a close homolog of heparanase. Hpa2, however, lacks intrinsic heparan sulfate (HS)-degrading activity, the hallmark of heparanase enzymatic activity. Mutations of HPSE2 were identified in patients diagnosed with urofacial syndrome (UFS), a rare genetic disorder that exhibits abnormal facial expression and bladder voiding dysfunction, leading to renal damage and eventually renal failure. In order to reveal the role of HPSE2 in tissue homeostasis, we established a conditional Hpa2-KO mouse. Interestingly, the lack of Hpa2 was associated with a marked decrease in the expression of key pancreatic transcription factors such as PTF1, GATA6, and Mist1. This was associated with a two-fold decrease in pancreas weight, increased pancreatic inflammation, and profound morphological alterations of the pancreas. These include massive accumulation of fat cells, possibly a result of acinar-to-adipocyte transdifferentiation (AAT), as well as acinar-to-ductal metaplasia (ADM), both considered to be pro-tumorigenic. Furthermore, exposing Hpa2-KO but not wild-type mice to a carcinogen (AOM) and pancreatic inflammation (cerulein) resulted in the formation of pancreatic intraepithelial neoplasia (PanIN), lesions that are considered to be precursors of invasive ductal adenocarcinoma of the pancreas (PDAC). These results strongly support the notion that Hpa2 functions as a tumor suppressor. Moreover, Hpa2 is shown here for the first time to play a critical role in the exocrine aspect of the pancreas.

Potential roles of heparanase in cancer therapy: Current trends and future direction

Heparanase (HPSE; heparanase-1) is an endo-β-glucuronidase capable of degrading the carbohydrate moiety of heparan sulfate proteoglycans, thus modulating and facilitating the remodeling of the extracellular matrix and basement membrane. HPSE activity is strongly associated with major human pathological complications, including but not limited to tumor progress and angiogenesis. Several lines of literature have shown that overexpression of HPSE leads to enhanced tumor growth and metastatic transmission, as well as poor prognosis. Gene silencing of HPSE or treatment of tumor with compounds that block HPSE activity are shown to remarkably attenuate tumor progression. Therefore, targeting HPSE is considered as a potential therapeutical strategy for the treatment of cancer. Intriguingly, recent findings disclose that heparanase-2 (HPSE-2), a close homolog of HPSE but lacking enzymatic activity, can also regulate antitumor mechanisms. Given the pleiotropic roles of HPSE, further investigation is in demand to determine the precise mechanism of regulating action of HPSE in different cancer settings. In this review, we first summarize the current understanding of HPSE, such as its structure, subcellular localization, and tissue distribution. Furthermore, we systematically review the pro- and antitumorigenic roles and mechanisms of HPSE in cancer progress. In addition, we delineate HPSE inhibitors that have entered clinical trials and their therapeutic potential.

What Are the Potential Roles of Nuclear Perlecan and Other Heparan Sulphate Proteoglycans in the Normal and Malignant Phenotype

The recent discovery of nuclear and perinuclear perlecan in annulus fibrosus and nucleus pulposus cells and its known matrix stabilizing properties in tissues introduces the possibility that perlecan may also have intracellular stabilizing or regulatory roles through interactions with nuclear envelope or cytoskeletal proteins or roles in nucleosomal-chromatin organization that may regulate transcriptional factors and modulate gene expression. The nucleus is a mechano-sensor organelle, and sophisticated dynamic mechanoresponsive cytoskeletal and nuclear envelope components support and protect the nucleus, allowing it to perceive and respond to mechano-stimulation. This review speculates on the potential roles of perlecan in the nucleus based on what is already known about nuclear heparan sulphate proteoglycans. Perlecan is frequently found in the nuclei of tumour cells; however, its specific role in these diseased tissues is largely unknown. The aim of this review is to highlight probable roles for this intriguing interactive regulatory proteoglycan in the nucleus of normal and malignant cell types.

Eosinophils in Eosinophilic Esophagitis: The Road to Fibrostenosis is Paved With Good Intentions

Eosinophilic esophagitis (EoE) is an antigen-driven disease associated with epithelial barrier dysfunction and chronic type 2 inflammation. Eosinophils are the defining feature of EoE histopathology but relatively little is known about their role in disease onset and progression. Classically defined as destructive, end-stage effector cells, eosinophils (a resident leukocyte in most of the GI tract) are increasingly understood to play roles in local immunity, tissue homeostasis, remodeling, and repair. Indeed, asymptomatic esophageal eosinophilia is observed in IgE-mediated food allergy. Interestingly, EoE is a potential complication of oral immunotherapy (OIT) for food allergy. However, we recently found that patients with peanut allergy may have asymptomatic esophageal eosinophilia at baseline and that peanut OIT induces transient esophageal eosinophilia in most subjects. This is seemingly at odds with multiple studies which have shown that EoE disease severity correlates with tissue eosinophilia. Herein, we review the potential role of eosinophils in EoE at different stages of disease pathogenesis. Based on current literature we suggest the following: (1) eosinophils are recruited to the esophagus as a homeostatic response to epithelial barrier disruption; (2) eosinophils mediate barrier-protective activities including local antibody production, mucus production and epithelial turnover; and (3) when type 2 inflammation persists, eosinophils promote fibrosis.

Heparanase and the hallmarks of cancer

Heparanase is the only mammalian enzyme that cleaves heparan sulphate, an important component of the extracellular matrix. This leads to the remodelling of the extracellular matrix, whilst liberating growth factors and cytokines bound to heparan sulphate. This in turn promotes both physiological and pathological processes such as angiogenesis, immune cell migration, inflammation, wound healing and metastasis. Furthermore, heparanase exhibits non-enzymatic actions in cell signalling and in regulating gene expression. Cancer is underpinned by key characteristic features that promote malignant growth and disease progression, collectively termed the 'hallmarks of cancer'. Essentially, all cancers examined to date have been reported to overexpress heparanase, leading to enhanced tumour growth and metastasis with concomitant poor patient survival. With its multiple roles within the tumour microenvironment, heparanase has been demonstrated to regulate each of these hallmark features, in turn highlighting the need for heparanase-targeted therapies. However, recent discoveries which demonstrated that heparanase can also regulate vital anti-tumour mechanisms have cast doubt on this approach. This review will explore the myriad ways by which heparanase functions as a key regulator of the hallmarks of cancer and will highlight its role as a major component within the tumour microenvironment. The dual role of heparanase within the tumour microenvironment, however, emphasises the need for further investigation into defining its precise mechanism of action in different cancer settings.

Heparanase: Historical Aspects and Future Perspectives

Heparanase is an endo-β-glucuronidase that cleaves at a limited number of internal sites the glycosaminoglycan heparan sulfate (HS). Heparanase enzymatic activity was first reported in 1975 and by 1983 evidence was beginning to emerge that the enzyme was a facilitator of tumor metastasis by cleaving HS chains present in blood vessel basement membranes and, thereby, aiding the passage of tumor cells through blood vessel walls. Due to a range of technical difficulties, it took another 16 years before heparanase was cloned and characterized in 1999 and a further 14 years before the crystal structure of the enzyme was solved. Despite these substantial deficiencies, there was steady progress in our understanding of heparanase long before the enzyme was fully characterized. For example, it was found as early as 1984 that activated T cells upregulate heparanase expression, like metastatic tumor cells, and the enzyme aids the entry of T cells and other leukocytes into inflammatory sites. Furthermore, it was discovered in 1989 that heparanase releases pre-existing growth factors and cytokines associated with HS in the extracellular matrix (ECM), the liberated growth factors/cytokines enhancing angiogenesis and wound healing. There were also the first hints that heparanase may have functions other than enzymatic activity, in 1995 it being reported that under certain conditions the enzyme could act as a cell adhesion molecule. Also, in the same year PI-88 (Muparfostat), the first heparanase inhibitor to reach and successfully complete a Phase III clinical trial was patented.Nevertheless, the cloning of heparanase (also known as heparanase-1) in 1999 gave the field an enormous boost and some surprises. The biggest surprise was that there is only one heparanase encoding gene in the mammalian genome, despite earlier research, based on substrate specificity, suggesting that there are at least three different heparanases. This surprising conclusion has remained unchanged for the last 20 years. It also became evident that heparanase is a family 79 glycoside hydrolase that is initially produced as a pro-enzyme that needs to be processed by proteases to form an enzymatically active heterodimer. A related molecule, heparanase-2, was also discovered that is enzymatically inactive but, remarkably, recently has been shown to inhibit heparanase-1 activity as well as acting as a tumor suppressor that counteracts many of the pro-tumor properties of heparanase-1.The early claim that heparanase plays a key role in tumor metastasis, angiogenesis and inflammation has been confirmed by many studies over the last 20 years. In fact, heparanase expression is enhanced in all major cancer types, namely carcinomas, sarcomas, and hematological malignancies, and correlates with increased metastasis and poor prognosis. Also, there is mounting evidence that heparanase plays a central role in the induction of inflammation-associated cancers. The enzymatic activity of heparanase has also emerged in unexpected situations, such as in the spread of HS-binding viruses and in Type-1 diabetes where the destruction of intracellular HS in pancreatic insulin-producing beta cells precipitates diabetes. But the most extraordinary recent discoveries have been with the realization that heparanase can exert a range of biological activities that are independent of its enzymatic function, most notably activation of several signaling pathways and being a transcription factor that controls methylation of histone tails. Collectively, these data indicate that heparanase is a truly multifunctional protein that has the additional property of cleaving HS chains and releasing from ECM and cell surfaces hundreds of HS-binding proteins with a plethora of functional consequences. Clearly, there are many unique features of this intriguing molecule that still remain to be explored and are highlighted in this Chapter.

Involvement of Heparan Sulfate and Heparanase in Neural Development and Pathogenesis of Brain Tumors

Brain tumors are aggressive and devastating diseases. The most common type of brain tumor, glioblastoma (GBM), is incurable and has one of the worst five-year survival rates of all human cancers. GBMs are invasive and infiltrate healthy brain tissue, which is one main reason they remain fatal despite resection, since cells that have already migrated away lead to rapid regrowth of the tumor. Curative therapy for medulloblastoma (MB), the most common pediatric brain tumor, has improved, but the outcome is still poor for many patients, and treatment causes long-term complications. Recent advances in the classification of pediatric brain tumors reveal distinct subgroups, allowing more targeted therapy for the most aggressive forms, and sparing children with less malignant tumors the side-effects of massive treatment. Heparan sulfate proteoglycans (HSPGs), main components of the neurogenic niche, interact specifically with a large number of physiologically important molecules and vital roles for HS biosynthesis and degradation in neural stem cell differentiation have been presented. HSPGs are composed of a core protein with attached highly charged, sulfated disaccharide chains. The major enzyme that degrades HS is heparanase (HPSE), an important regulator of extracellular matrix (ECM) remodeling which has been suggested to promote the growth and invasion of other types of tumors. This is of clinical interest because GBM are highly invasive and children with metastatic MB at the time of diagnosis exhibit a worse outcome. Here we review the involvement of HS and HPSE in development of the nervous system and some of its most malignant brain tumors, glioblastoma and medulloblastoma.

Heparanase and Type 1 Diabetes

Type 1 diabetes (T1D) results from autoimmune destruction of insulin-producing beta cells in pancreatic islets. The degradation of the glycosaminoglycan heparan sulfate (HS) by the endo-β-D-glycosidase heparanase plays a critical role in multiple stages of the disease process. Heparanase aids (i) migration of inflammatory leukocytes from the vasculature to the islets, (ii) intra-islet invasion by insulitis leukocytes, and (iii) selective destruction of beta cells. These disease stages are marked by the solubilization of HS in the subendothelial basement membrane (BM), HS breakdown in the peri-islet BM, and the degradation of HS inside beta cells, respectively. Significantly, healthy islet beta cells are enriched in highly sulfated HS which is essential for their viability, protection from damage by reactive oxygen species (ROS), beta cell function and differentiation. Consequently, mouse and human beta cells but not glucagon-producing alpha cells (which contain less-sulfated HS) are exquisitely vulnerable to heparanase-mediated damage. In vitro, the death of HS-depleted mouse and human beta cells can be prevented by HS replacement using highly sulfated HS mimetics or analogues. T1D progression in NOD mice and recent-onset T1D in humans correlate with increased expression of heparanase by circulating leukocytes of myeloid origin and heparanase-expressing insulitis leukocytes. Treatment of NOD mice with the heparanase inhibitor and HS replacer, PI-88, significantly reduced T1D incidence by 50%, impaired the development of insulitis and preserved beta cell HS. These outcomes identified heparanase as a novel destructive tool in T1D, distinct from the conventional cytotoxic and apoptosis-inducing mechanisms of autoreactive T cells. In contrast to exogenous catalytically active heparanase, endogenous heparanase may function in HS homeostasis, gene expression and insulin secretion in normal beta cells and immune gene expression in leukocytes. In established diabetes, the interplay between hyperglycemia, local inflammatory cells (e.g. macrophages) and heparanase contributes to secondary micro- and macro-vascular disease. We have identified dual activity heparanase inhibitors/HS replacers as a novel class of therapeutic for preventing T1D progression and potentially for mitigating secondary vascular disease that develops with long-term T1D.

Heparanase: A Dynamic Promoter of Myeloma Progression

It has been speculated for many years that heparanase plays an important role in the progression of cancer due largely to the finding that its expression is weak or absent in normal tissues but generally as tumors become more aggressive heparanase expression increases. However, it is only in the last decade or so that we have begun to understand the molecular mechanism behind the sinister role that heparanase plays in cancer. In this review, we describe the many functions of heparanase in promoting the growth, angiogenesis and metastasis of multiple myeloma, a devastating cancer that localizes predominantly within the bone marrow and spreads throughout the skeletal system devouring bone and ultimately leading to death of almost all patients diagnosed with this disease. We also explore recent discoveries related to how heparanase primes exosome biogenesis and how heparanase enhances myeloma tumor chemoresistance. Discovery of these multiple tumor-promoting pathways that are driven by heparanase identified the enzyme as an ideal target for therapy, an approach recently tested in a Phase I trial in myeloma patients.

Heparanase: A Challenging Cancer Drug Target

Heparanase has been viewed as a promising anti-cancer drug target for almost two decades, but no anti-heparanase therapy has yet reached the clinic. This endoglycosidase is highly expressed in a variety of malignancies, and its high expression is associated with greater tumor size, more metastases, and a poor prognosis. It was first described as an enzyme cleaving heparan sulfate chains of proteoglycans located in extracellular matrices and on cell surfaces, but this is not its only function. It is a multi-functional protein with activities that are enzymatic and non-enzymatic and which take place both outside of the cell and intracellularly. Knowledge of the crystal structure of heparanase has assisted the interpretation of earlier structure-function studies as well as in the design of potential anti-heparanase agents. This review re-examines the various functions of heparanase in light of the structural data. The functions of the heparanase variant, T5, and structure and functions of heparanase-2 are also examined as these heparanase related, but non-enzymatic, proteins are likely to influence the in vivo efficacy of anti-heparanase drugs. The anti-heparanase drugs currently under development predominately focus on inhibiting the enzymatic activity of heparanase, which, in the absence of inhibitors with high clinical efficacy, prompts a discussion of whether this is the best approach. The diversity of outcomes attributed to heparanase and the difficulties of unequivocally determining which of these are due to its enzymatic activity is also discussed and leads us to the conclusion that heparanase is a valid, but challenging drug target for cancer.

Cardiomyocyte-endothelial cell control of lipoprotein lipase

In people with diabetes, inadequate pharmaceutical management predisposes the patient to heart failure, which is the leading cause of diabetes related death. One instigator for this cardiac dysfunction is change in fuel utilization by the heart. Thus, following diabetes, when cardiac glucose utilization is impaired, the heart undergoes metabolic transformation wherein it switches to using fats as an exclusive source of energy. Although this switching is geared to help the heart initially, in the long term, this has detrimental effects on cardiac function. These include the generation of noxious byproducts, which damage the cardiomyocytes, and ultimately result in increased morbidity and mortality. A key perpetrator that may be responsible for organizing this metabolic disequilibrium is lipoprotein lipase (LPL), the enzyme responsible for providing fat to the hearts. Either exaggeration or reduction in its activity following diabetes could lead to heart dysfunction. Given the disturbing news that diabetes is rampant across the globe, gaining more insight into the mechanism(s) by which cardiac LPL is regulated may assist other researchers in devising new therapeutic strategies to restore metabolic equilibrium, to help prevent or delay heart disease seen during diabetes. This article is part of a Special Issue entitled: Heart Lipid Metabolism edited by G.D. Lopaschuk.

The function of heparanase in diabetes and its complications

Heparan sulfate proteoglycans are ubiquitous glycoproteins that contain several heparan sulfate polysaccharide side chains attached to a core protein. They function not only as a primary structural component of the extracellular matrix, but also provide a storage depot for bioactive molecules, such as basic fibroblast growth factor, vascular endothelial growth factor and lipoprotein lipase. Heparanase is an endoglycosidase that specifically hydrolyzes heparan sulfate into oligosaccharides. Recent studies have indicated that heparanase is engaged in the initiation and progression of diabetes, in addition to its associated complications. This review focuses on the participation of heparanase in the cleavage of heparan sulfate proteoglycans in pancreatic islets promoting beta cell death, promotion of atherosclerosis, and its role in cardiac metabolic switching in the early stage of cardiomyopathy during diabetes. Understanding the mechanisms by which heparanase is regulated in diabetes could provide a drug target to prevent diabetes and its complications.

Intrinsic and extrinsic regulation of cardiac lipoprotein lipase following diabetes

Cardiac lipoprotein lipase (LPL) is a pivotal enzyme controlling heart metabolism by providing the majority of fatty acids required by this organ. From activation in cardiomyocytes to secretion to the vascular lumen, cardiac LPL is regulated by multiple pathways, which are altered during diabetes. Hence, dimerization/activation of LPL is modified following diabetes, a process controlled by lipase maturation factor 1. The role of AMP-activated protein kinase, protein kinase D, and heparan sulfate proteoglycans, intrinsic factors that regulate the intracellular transport of LPL is also shifted, and is discussed. More recent studies have identified several exogenous factors released from endothelial cells (EC) and adipose tissue that are required for proper functioning of LPL. In response to hyperglycemia, both active and latent heparanase are released from EC to facilitate LPL secretion. Diabetes also increased the expression of glycosylphosphatidylinositol-anchored high density lipoprotein-binding protein 1 (GPIHBP1) in EC, which mediates the transport of LPL across EC. Angiopoietin-like protein 4 secreted from the adipose tissue has the potential to reduce coronary LPL activity. Knowledge of these intrinsic and extrinsic factors could be used develop therapeutic targets to normalize LPL function, and maintain cardiac energy homeostasis after diabetes.

Modification of heparanase gene expression in response to conditioning and LPS treatment: strong correlation to rs4693608 SNP

Heparanase is an endo-β-glucuronidase that specifically cleaves the saccharide chains of HSPGs, important structural and functional components of the ECM. Cleavage of HS leads to loss of the structural integrity of the ECM and release of HS-bound cytokines, chemokines, and bioactive angiogenic- and growth-promoting factors. Our previous study revealed a highly significant correlation of HPSE gene SNPs rs4693608 and rs4364254 and their combination with the risk of developing GVHD. We now demonstrate that HPSE is up-regulated in response to pretransplantation conditioning, followed by a gradual decrease thereafter. Expression of heparanase correlated with the rs4693608 HPSE SNP before and after conditioning. Moreover, a positive correlation was found between recipient and donor rs4693608 SNP discrepancy and the time of neutrophil and platelet recovery. Similarly, the discrepancy in rs4693608 HPSE SNP between recipients and donors was found to be a more significant factor for the risk of aGVHD than patient genotype. The rs4693608 SNP also affected HPSE gene expression in LPS-treated MNCs from PB and CB. Possessors of the AA genotype exhibited up-regulation of heparanase with a high ratio in the LPS-treated MNCs, whereas individuals with genotype GG showed down-regulation or no effect on HPSE gene expression. HPSE up-regulation was mediated by TLR4. The study emphasizes the importance of rs4693608 SNP for HPSE gene expression in activated MNCs, indicating a role in allogeneic stem cell transplantation, including postconditioning, engraftment, and GVHD.

Heparan sulfate in the nucleus and its control of cellular functions

Heparan sulfate proteoglycans (HSPG) are present on the cell surface, within the extracellular matrix, and as soluble molecules in tissues and blood. HSPGs are known to regulate a wide range of cellular functions predominantly by serving as co-receptors for growth factors, chemokines, and other regulatory proteins that control inflammation, wound healing and tumorigenesis. Several studies have demonstrated the presence of heparan sulfate (HS) or HSPGs in the cell nucleus, but little attention has been focused on their role there. However, evidence is mounting that nuclear HS and HSPGs have important regulatory functions that impact the cell cycle, proliferation, transcription and transport of cargo to the nucleus. The discovery of proteoglycans in the nucleus extends the list of "non-traditional nuclear proteins" that includes, for example, cytoskeletal proteins such as actin and tubulin, and growth factors and their receptors. In this review we discuss the discovery and fascinating roles of HS and HSPGs in the nucleus and propose a number of key questions that remain to be addressed.

Unexpected new roles for heparanase in Type 1 diabetes and immune gene regulation

Heparanase (Hpse) is an endo-β-d-glucuronidase that degrades the glycosaminoglycan heparan sulfate (HS) in basement membranes (BMs) to facilitate leukocyte migration into tissues. Heparanase activity also releases HS-bound growth factors from the extracellular matrix (ECM), a function that aids wound healing and angiogenesis. In disease states, the degradation of HS in BMs by heparanase is well recognized as an invasive property of metastatic cancer cells. Recent studies by our group, however, have identified unexpected new roles for heparanase and HS. First, we discovered that in Type 1 diabetes (T1D) (i) HS in the pancreatic islet BM acts as a barrier to invading cells and (ii) high levels of HS within the insulin-producing islet beta cells themselves are critical for beta cell survival, protecting the cells from free radical-mediated damage. Furthermore, catalytically active heparanase produced by autoreactive T cells and other insulitis mononuclear cells was shown to degrade intra-islet HS, increasing the susceptibility of islet beta cells to free radical damage and death. This totally novel molecular explanation for the onset of T1D diabetes opens up new therapeutic approaches for preventing disease progression. Indeed, administration of the heparanase inhibitor, PI-88, dramatically reduced T1D incidence in diabetes-prone NOD mice, preserved islet beta cell HS and reduced islet inflammation. Second, in parallel studies it has been shown that heparanase and HS can be transported to the nucleus of cells where they impact directly or indirectly on gene transcription. Based on ChIP-on-chip studies heparanase was found to interact with the promoters and transcribed regions of several hundred genes and micro-RNAs in activated Jurkat T cells and up-regulate transcription, with many of the target genes/micro-RNAs being involved in T cell differentiation. At the molecular level, nuclear heparanase appears to regulate histone 3 lysine 4 (H3K4) methylation by influencing the recruitment of demethylases to transcriptionally active genes. These studies have unveiled new functions for heparanase produced by T lymphocytes, with the enzyme mediating unexpected intracellular effects on T cell differentiation and insulin-producing beta cell survival in T cell-dependent autoimmune T1D.

Involvement of heparanase in atherosclerosis and other vessel wall pathologies

Heparanase, the sole mammalian endoglycosidase degrading heparan sulfate, is causally involved in cancer metastasis, angiogenesis, inflammation and kidney dysfunction. Despite the wide occurrence and impact of heparan sulfate proteoglycans in vascular biology, the significance of heparanase in vessel wall disorders is underestimated. Blood vessels are highly active structures whose morphology rapidly adapts to maintain vascular function under altered systemic and local conditions. In some pathologies (restenosis, thrombosis, atherosclerosis) this normally beneficial adaptation may be detrimental to overall function. Enzymatic dependent and independent effects of heparanase on arterial structure mechanics and repair closely regulate arterial compliance and neointimal proliferation following endovascular stenting. Additionally, heparanase promotes thrombosis after vascular injury and contributes to a pro-coagulant state in human carotid atherosclerosis. Importantly, heparanase is closely associated with development and progression of atherosclerotic plaques, including stable to unstable plaque transition. Consequently, heparanase levels are markedly increased in the plasma of patients with acute myocardial infarction. Noteworthy, heparanase activates macrophages, resulting in marked induction of cytokine expression associated with plaque progression towards vulnerability. Together, heparanase emerges as a regulator of vulnerable lesion development and potential target for therapeutic intervention in atherosclerosis and related vessel wall complications.

The heparanase/syndecan-1 axis in cancer: mechanisms and therapies

Heparanase is an endoglucuronidase that cleaves heparan sulfate chains of proteoglycans. In many malignancies, high heparanase expression and activity correlate with an aggressive tumour phenotype. A major consequence of heparanase action in cancer is a robust up-regulation of growth factor expression and increased shedding of syndecan-1 (a transmembrane heparan sulfate proteoglycan). Substantial evidence indicates that heparanase and syndecan-1 work together to drive growth factor signalling and regulate cell behaviours that enhance tumour growth, dissemination, angiogenesis and osteolysis. Preclinical and clinical studies have demonstrated that therapies targeting the heparanase/syndecan-1 axis hold promise for blocking the aggressive behaviour of cancer.

Antiproliferative effect of a novel mTOR inhibitor temsirolimus contributes to the prolonged survival of orthotopic esophageal cancer-bearing mice

Esophageal squamous cell carcinoma (ESCC) remains one of the most aggressive cancers with poor prognosis regardless of a several reports that indicate a better therapeutic efficacy using some new chemotherapeutic agents. Recent drug development has contributed to an improved specificity to suppress mTOR activity by which many types of malignancies can be explosively progressed. Temsirolimus (CCI-779, TricelTM) is one of recently synthesized analogs of rapamycin and has provided better outcomes for patients with renal cell carcinoma. In this study, we experimentally evaluated an efficacy of targeting mTOR by temsirolimus for ESCC treatment, with an assessment of its survival advantage using an advanced ESCC animal model. First, we confirmed that the expression of phosphorylated mTOR was increased in 46 of 58 clinical ESCC tumor tissues (79.3%) and appeared to get strengthened with tumor progression. All of ESCC cell lines used in this study revealed an increase of mTOR phosphorylation, accompanied with the upregulation of hypoxia inducible factor-I α (HIF-1α), one of the critical effectors regulated by mTOR. Temsirolimus treatment apparently suppressed the activation of mTOR and its downstream effectors, resulting in the reduced ability of ESCC cell proliferation. Finally, the weekly administration of temsirolimus significantly diminished the size of subcutaneous tumors (vehicle, 3261.6 ± 722.0; temsirolimus, 599.2 ± 122.9; p = 0.007) in nude mice and effectively prolonged orthotopic esophageal cancer-bearing mice (median survival periods: control, 31 d; temsirolimus, 43 d; p = 0.0024). These data suggests that targeting mTOR by temsirolimus may become a therapeutic alternative for esophageal cancer, with a contribution to a better outcome.

The endoglycosidase heparanase enters the nucleus of T lymphocytes and modulates H3 methylation at actively transcribed genes via the interplay with key chromatin modifying enzymes

The methylation of histones is a fundamental epigenetic process regulating gene expression programs in mammalian cells. Dysregulated patterns of histone methylation are directly implicated in malignant transformation. Here, we report the unexpected finding that the invasive extracellular matrix degrading endoglycosidase heparanase enters the nucleus of activated human T lymphocytes and regulates the transcription of a cohort of inducible immune response genes by controlling histone H3 methylation patterns. It was found that nuclear heparanase preferentially associates with euchromatin. Genome-wide ChIP-on-chip analyses showed that heparanase is recruited to both the promoter and transcribed regions of a distinct cohort of transcriptionally active genes. Knockdown and overexpression of the heparanase gene also showed that chromatin-bound heparanase is a prerequisite for the transcription of a subset of inducible immune response genes in activated T cells. Furthermore, the actions of heparanase seem to influence gene transcription by associating with the demethylase LSD1, preventing recruitment of the methylase MLL and thereby modifying histone H3 methylation patterns. These data indicate that heparanase belongs to an emerging class of proteins that play an important role in regulating transcription in addition to their well-recognized extra-nuclear functions.

Significance of heparanase in cancer and inflammation

Heparan sulfate proteoglycans (HSPGs) are primary components at the interface between virtually every eukaryotic cell and its extracellular matrix. HSPGs not only provide a storage depot for heparin-binding molecules in the cell microenvironment, but also decisively regulate their accessibility, function and mode of action. As such, they are intimately involved in modulating cell invasion and signaling loops that are critical for tumor growth, inflammation and kidney function. In a series of studies performed since the cloning of the human heparanase gene, we and others have demonstrated that heparanase, the sole heparan sulfate degrading endoglycosidase, is causally involved in cancer progression, inflammation and diabetic nephropathy and hence is a valid target for drug development. Heparanase is causally involved in inflammation and accelerates colon tumorigenesis associated with inflammatory bowel disease. Notably, heparanase stimulates macrophage activation, while macrophages induce production and activation of latent heparanase contributed by the colon epithelium, together generating a vicious cycle that powers colitis and the associated tumorigenesis. Heparanase also plays a decisive role in the pathogenesis of diabetic nephropathy, degrading heparan sulfate in the glomerular basement membrane and ultimately leading to proteinuria and kidney dysfunction. Notably, clinically relevant doses of ionizing radiation (IR) upregulate heparanase expression and thereby augment the metastatic potential of pancreatic carcinoma. Thus, combining radiotherapy with heparanase inhibition is an effective strategy to prevent tumor resistance and dissemination in IR-treated pancreatic cancer patients. Also, accumulating evidence indicate that peptides derived from human heparanase elicit a potent anti-tumor immune response, suggesting that heparanase represents a promising target antigen for immunotherapeutic approaches against a broad variety of tumours. Oligosaccharide-based compounds that inhibit heparanase enzymatic activity were developed, aiming primarily at halting tumor growth, metastasis and angiogenesis. Some of these compounds are being evaluated in clinical trials, targeting both the tumor and tumor microenvironment.

Pre-clinical and clinical significance of heparanase in Ewing's sarcoma

Heparanase is an endoglycosidase that specifically cleaves heparan sulphate side chains of heparan sulphate proteoglycans, activity that is strongly implicated in cell migration and invasion associated with tumour metastasis, angiogenesis and inflammation. Heparanase up-regulation was documented in an increasing number of human carcinomas, correlating with reduced post-operative survival rate and enhanced tumour angiogenesis. Expression and significance of heparanase in human sarcomas has not been so far reported. Here, we applied the Ewing's sarcoma cell line TC71 and demonstrated a potent inhibition of cell invasion in vitro and tumour xenograft growth in vivo upon treatment with a specific inhibitor of heparanase enzymatic activity (compound SST0001, non-anticoagulant N-acetylated, glycol split heparin). Next, we examined heparanase expression and cellular localization by immunostaining of a cohort of 69 patients diagnosed with Ewing's sarcoma. Heparanase staining was noted in all patients. Notably, heparanase staining intensity correlated with increased tumour size (P = 0.04) and with patients' age (P = 0.03), two prognostic factors associated with a worse outcome. Our study indicates that heparanase expression is induced in Ewing's sarcoma and associates with poor prognosis. Moreover, it encourages the inclusion of heparanase inhibitors (i.e. SST0001) in newly developed therapeutic modalities directed against Ewing's sarcoma and likely other malignancies.

Heparan sulfate and heparanase play key roles in mouse β cell survival and autoimmune diabetes

The autoimmune type 1 diabetes (T1D) that arises spontaneously in NOD mice is considered to be a model of T1D in humans. It is characterized by the invasion of pancreatic islets by mononuclear cells (MNCs), which ultimately leads to destruction of insulin-producing β cells. Although T cell dependent, the molecular mechanisms triggering β cell death have not been fully elucidated. Here, we report that a glycosaminoglycan, heparan sulfate (HS), is expressed at extraordinarily high levels within mouse islets and is essential for β cell survival. In vitro, β cells rapidly lost their HS and died. β Cell death was prevented by HS replacement, a treatment that also rendered the β cells resistant to damage from ROS. In vivo, autoimmune destruction of islets in NOD mice was associated with production of catalytically active heparanase, an HS-degrading enzyme, by islet-infiltrating MNCs and loss of islet HS. Furthermore, in vivo treatment with the heparanase inhibitor PI-88 preserved intraislet HS and protected NOD mice from T1D. Our results identified HS as a critical molecular requirement for islet β cell survival and HS degradation as a mechanism for β cell destruction. Our findings suggest that preservation of islet HS could be a therapeutic strategy for preventing T1D.

Fatty acid-induced nuclear translocation of heparanase uncouples glucose metabolism in endothelial cells

OBJECTIVE

Heparanase is an endoglycosidase that specifically cleaves carbohydrate chains of heparan sulfate. We have recently reported that high fatty acid increased the nuclear content of endothelial heparanase. Here, we examined the mechanism and the consequences behind this nuclear translocation of heparanase.

METHODS AND RESULTS

Bovine coronary artery endothelial cells were grown to confluence and incubated with palmitic acid. Palmitic acid induced rapid nuclear accumulation of heparanase that was dependent on Bax activation and lysosome permeabilization. Heat shock protein 90 was an important mediator of palmitic acid-induced shuttling of heparanase to the nucleus. Nuclear heparanase promoted cleavage of heparan sulfate, a potent inhibitor of histone acetyltransferase activity and gene transcription. A TaqMan gene expression assay revealed an increase in genes related to glucose metabolism and inflammation. In addition, glycolysis was uncoupled from glucose oxidation, resulting in accumulation of lactate.

CONCLUSIONS

The results presented in this study demonstrate that fatty acid can provoke lysosomal release of heparanase, its nuclear translocation, activation of genes controlling glucose metabolism, and accumulation of lactate. Given that lactate and inflammation have been implicated in the progression of atherosclerosis, our data may serve to reduce the associated cardiovascular complications seen during diabetes.

Activation of heparanase by ultraviolet B irradiation leads to functional loss of basement membrane at the dermal-epidermal junction in human skin

Recently, we reported that heparanase plays important roles in barrier-disrupted skin, leading to increased interaction of growth factors between epidermis and dermis and facilitating various cutaneous changes, including epidermal hyperplasia and wrinkle formation. However, the role of heparanase in sun-exposed skin remains unknown. Here, we show that heparanase in human keratinocytes is activated by ultraviolet B (UVB) exposure and that heparan sulfate of perlecan is markedly degraded in UVB-irradiated human skin. The degradation of heparan sulfate resulted in a marked reduction of binding activity of the basement membrane for vascular endothelial growth factor, fibroblast growth factor-2 and -7 at the dermal-epidermal junction. Degradation of heparan sulfate was observed not only in acutely UVB-irradiated skin, but also in skin chronically exposed to sun. Interestingly, heparan sulfate was found to be degraded in sun-exposed skin, but not in sun-protected skin. These findings suggest that chronic UVB exposure activates heparanase, leading to degradation of heparan sulfate in the basement membrane and increased growth factor interaction between epidermis and dermis. These changes may facilitate photo-aging.

Prognostic value of heparanase expression and cellular localization in oral cancer

BACKGROUND

Metastases formation depends on the ability of tumor cells to invade basement membranes in a process involving enzymes capable of degrading extracellular matrix components.

METHODS

We examined the expression of heparanase in oral carcinomas and correlated its staining extent, intensity, and cellular localization with patients' outcome.

RESULTS

Quantitative real-time polymerase chain reaction (PCR) revealed over 4-fold increase in heparanase levels in oral carcinomas compared to adjacent normal tissue. Normal oral epithelium was found negative for heparanase, while all oral carcinomas stained positively for heparanase. Heparanase staining was associated with Ki67 staining, a measure of cell proliferation. Notably, whereas cytoplasmic localization of heparanase was associated with high-grade carcinomas, nuclear localization of the enzyme was found primarily in low-grade, well-differentiated tumors, and in all oral verrucous carcinomas.

CONCLUSION

Expression level and cellular localization of heparanase could serve as an important diagnostic marker in patients with oral cancer.

Epidermal growth factor-induced heparanase nucleolar localization augments DNA topoisomerase I activity in brain metastatic breast cancer

Identification of molecular mechanisms responsible for brain metastatic breast cancer (BMBC) is imperative to develop novel therapies. However, current understanding of the molecular circuitry that governs BMBC dissemination remains fragmentary. Heparanase (HPSE) is the only functional mammalian endoglycosidase whose activity correlates with cancer metastasis, angiogenesis, and the reduced postoperative survival of cancer patients, making it an active target for anticancer therapeutics. We hypothesized that human epidermal growth factor receptor 2 (HER2)/epidermal growth factor receptor (EGFR) activation promotes HPSE function in human BMBC. To address this, we examined HPSE content, activity, and intracellular trafficking in a HER2/EGFR-expressing BMBC model system and show that HPSE is present, functional, and correlates with HER2 status. Further, we showed that EGF induced nucleolar translocation of HPSE in these cells in a dose- and time-dependent manner upon activation of HER2/EGFR. Knockdowns of HER2/EGFR by small interference RNA abolished EGF-induced HPSE nucleolar translocalization. It was also noted that nucleolar HPSE modulates DNA topoisomerase I (Topo I), an enzyme that is highly present in nucleoli, essential for DNA replication and transcription in a variety of tumors, and inhibited by heparan sulfate. Evidence is provided that HPSE can regulate Topo I activity, which subsequently affects BMBC cell proliferation. Finally, we showed that the nucleolar presence of HPSE with Topo I colocalization is detected only in HER2-overexpressing BMBC patient specimens. Altogether, these findings support the notion that HPSE is a critical downstream target of HER2 mechanisms driving BMBC and is potentially relevant for BMBC therapeutic interventions.

The development and characterization of an organotypic tissue-engineered human esophageal mucosal model

There is a demand for a reliable three-dimensional tissue-engineered model of the esophageal mucosa for use as an experimental platform for investigating esophageal epithelial biology and the pathogenesis of esophageal neoplasia and precursor lesions such as Barrett's metaplasia. A number of models have been described, but there has been little systematic assessment of the different approaches, making selection of a preferred platform difficult. This study assesses the properties of organotypic cultures using four different scaffolds (human esophageal matrix, porcine esophageal matrix, human dermal matrix, and collagen) and two different epithelial cell types (primary human esophageal squamous cells and the Het-1A esophageal squamous cell line). Human esophageal matrix and dermis did not give consistent results, but porcine esophageal matrix and collagen proved more reliable and were studied in greater detail. Both matrices supported the formation of a mature stratified epithelium that was similar to that of the normal human esophagus, demonstrated by Ki67, CK4, CK14, and involucrin staining. However, collagen showed reduced epithelial adherence, while fibroblast penetration into the porcine matrix was poor. Composite cultures using Het-1A cells formed a hyperproliferative epithelium with no evidence of differentiation. We propose human esophageal squamous cells seeded onto porcine esophageal matrix as the preferred model of the normal human esophagus.

Coordinate interaction between IL-13 and epithelial differentiation cluster genes in eosinophilic esophagitis

We have previously proposed that the pathogenesis of eosinophilic esophagitis (EE) is mediated by an IL-13-driven epithelial cell response associated with marked gene dysregulation including eotaxin-3 overproduction. In this study, we compared epithelial responses between healthy patients and those with EE, aiming to uncover molecular explanations for EE pathogenesis. Esophageal epithelial cells could be maintained for up to five passages, with 67% and 62% of cell lines reaching confluence in healthy controls and EE cases, respectively. Both sets of epithelial cells avidly responded to IL-13 at similar levels as assessed by eotaxin-3 production. Acidic pH increased cellular release of eotaxin-3 (4.6 +/- 1.98 ng/ml versus 12.46 +/- 2.90 ng/ml at pH 7.4 and 4, respectively; p < 0.05). Numerous epidermal differentiation complex (EDC) genes, such as filaggrin and SPRR3, were downregulated both in IL-13-stimulated esophageal epithelial cells and in EE biopsies specimens compared with healthy controls. Whereas the filaggrin loss of function mutation 2282del4 was overrepresented in EE compared with control individuals (6.1% versus 1.3% respectively; p = 0.0172), the decreased filaggrin expression was uniformly seen in all EE cases in vivo. Indeed, expression of the EDC genes filaggrin and involucrin was strongly decreased directly by IL-13. These results establish that the epithelial response in EE involves a cooperative interaction between IL-13 and expression of EDC genes.

Heparanase and hepatocellular carcinoma: Promoter or inhibitor?

Heparan sulphate proteoglycans (HSPGs) consist of a core protein and several heparan sulphate (HS) side chains covalently linked. HS also binds a great deal of growth factors, chemokines, cytokines and enzymes to the extracellular matrix and cell surface. Heparanase can specially cleave HS side chains from HSPGs. There are a lot of conflicting reports about the role of heparanase in hepatocellular carcinoma (HCC). Heparanase is involved in hepatitis B virus infection and hepatitis C virus infection, the activation of signal pathways, metastasis and apoptosis of HCC. Heparanase is synthesized as an inactive precursor within late endosomes and lysosomes. Then heparanase undergoes proteolytic cleavage to form an active enzyme in lysosomes. Active heparanase translocates to the nucleus, cell surface or extracellular matrix. Different locations of heparanase may exert different activities on tumor progression. Furthermore, enzymatic activities and non-enzymatic activities of heparanase may play different roles during HCC development. The expression level of heparanase may also contribute to the discrepant effects of heparanase. Growth promoting as well as growth inhibiting sequences are contained within the tumor cell surface heparan sulfate. Degrading different HSPGs by heparanase may play different roles in HCC. Systemic studies examining the processing, expression, localization and function of heparanase should shed a light on the role of heparanase in HCC.

Heparanase expression by Barrett's epithelium and during esophageal carcinoma progression

Enzymatic activity responsible for the cleavage of heparan sulfate, commonly known as heparanase, is abundant in tumor-derived cells. Heparanase cleaves heparan sulfate side chains, presumably at sites of low sulfation, thus facilitating structural alterations of the extracellular matrix and basement membrane underlying epithelial and endothelial cells. Traditionally, heparanase activity was correlated with the metastatic potential of tumor-derived cells, attributed to enhanced cell dissemination as a consequence of heparan sulfate cleavage and remodeling of the extracellular matrix barrier. More recently, heparanase upregulation was documented in an increasing number of human carcinomas and hematological malignancies, correlating with increased tumor metastasis, vascular density, and shorter post-operative survival of cancer patients. Although heparanase upregulation and its pro-malignant features are well documented, the instance of its induction in the course of tumor development was less investigated. Here, we used immunohistochemical analysis to investigate heparanase expression in normal esophagus, Barrett's esophagus without dysplasia, Barrett's esophagus with low-grade dysplasia, Barrett's esophagus with high-grade dysplasia, and adenocarcinoma of the esophagus. We report that heparanase expression is already induced in Barrett's epithelium without dysplasia, and is further increased during progression through distinct pathological stages, namely, low-grade dysplasia, high-grade dysplasia, and adenocarcinoma. Notably, heparanase induction correlated with increased cell proliferation index revealed by Ki-67 staining. These findings suggest that heparanase function is not limited to the process of tumor metastasis, but rather is engaged at the early stages of esophagus carcinoma initiation and progression.

Heparanase induces VEGF C and facilitates tumor lymphangiogenesis

Heparanase is an endoglycosidase that specifically cleaves heparan sulfate side chains, a class of glycosaminoglycans abundantly present in the extracellular matrix and on the cell surface. Heparanase activity is strongly implicated in tumor angiogenesis and metastasis attributed to remodeling of the subepithelial and subendothelial basement membranes. We hypothesized that similar to its proangiogenic capacity, heparanase is also engaged in lymphangiogenesis and utilized the D2-40 monoclonal antibody to study lymphangiogenesis in tumor specimens obtained from 65 head and neck carcinoma patients. Lymphatic density was analyzed for association with clinical parameters and heparanase staining. We provide evidence that lymphatic vessel density (LVD) correlates with head and neck lymph node metastasis (N-stage, p = 0.007) and inversely correlates with tumor cell differentiation (p = 0.007). Notably, heparanase staining correlated with LVD (p = 0.04) and, moreover, with VEGF C levels (p = 0.01). We further demonstrate that heparanase overexpression by epidermoid, breast, melanoma and prostate carcinoma cells induces a 3- to 5-fold elevation in VEGF C expression in vitro and facilitates tumor xenograft lymphangiogenesis in vivo, whereas heparanase gene silencing was associated with decreased VEGF C levels. These findings suggest that heparanase plays a unique dual role in tumor metastasis, facilitating tumor cell invasiveness and inducing VEGF C expression, thereby increasing the density of lymphatic vessels that mobilize metastatic cells.

Heparanase is overexpressed in lung cancer and correlates inversely with patient survival

BACKGROUND

Heparanase is an endo-beta-D-glucuronidase that is capable of cleaving heparan sulfate (HS) side chains at a limited number of sites, yielding HS fragments of still appreciable size (approximately 5-7 kDa). Heparanase activity has been detected frequently in several cell types and tissues. Heparanase activity correlates with the metastatic potential of tumor-derived cells, a correlation that has been attributed to enhanced cell dissemination as a consequence of HS cleavage and remodeling of the extracellular matrix barrier.

METHODS

In this study, the authors examined heparanase expression in 114 patients with lung cancer by means of immunohistochemistry and correlated clinical-pathologic data with heparanase immunostaining and cellular localization.

RESULTS

Heparanase was overexpressed in 75% of the study patients. Heparanase expression was correlated with lung cancer lymph node status and metastasis classification (P = .04 and P = .01, respectively) and was correlated inversely with patient survival (P = .007). It is noteworthy that this adverse effect depended largely on the cellular localization of heparanase. Thus, whereas cytoplasmic staining of heparanase is associated with a poor prognosis, nuclear heparanase predicts a favorable outcome for patients with lung cancer.

CONCLUSIONS

The current findings suggest that heparanase expression and cellular localization are decisive for lung cancer patients' prognosis, most likely because of heparanase-mediated tumor cell dissemination by blood and lymph vessels.

Heparanase 1: a key participant of inner root sheath differentiation program and hair follicle homeostasis

Heparanase is a heparan sulphate endo-glycosidase which was previously detected in the outer root sheath of murine hair follicles. Heparanase overexpression was reported to improve mouse hair (re)growth. In this study, we investigated its involvement in human hair biology. Immunofluorescence detection was used to explore heparanase distribution in both anagen and catagen hair follicles. Heparanase functionality was assessed in in vitro cultured hair follicles, in the presence of a heparanase activity inhibitor. Our results showed that heparanase expression was (i) primarily located in the inner root sheath (IRS) of human hair follicle, and there (ii) restricted to anagen phase. Furthermore, inhibition of heparanase in in vitro cultured hair follicles induced a catagen-like process. Hair shaft retreat upward was accompanied by a decrease in Ki67-positive cells, the formation of an epithelial strand as evidenced by K14 keratin expression, and the loss of IRS as assessed by transglutaminase 1 and desmoglein labelling. IRS distribution of heparanase and the induction of catagen-like involution of hair follicles when a potent heparanase inhibitor is added suggest that heparanase is a key actor of IRS differentiation and hair homeostasis.

Mammalian heparanase: what is the message?

Heparan sulphate proteoglycans are ubiquitous macromolecules of cell surfaces and extracellular matrices. Numerous extracellular matrix proteins, growth factors, morphogens, cytokines, chemokines and coagulation factors are bound and regulated by heparan sulphate. Degradation of heparan sulphate thus potentially profoundly affects cell and tissue function. Although there is evidence that several heparan sulphate-degrading endoglucuronidases (heparanases) might exist, so far only one transcript encoding a functional heparanase has been identified: heparanase-1. In the first part of this review, we discuss the current knowledge about heparan sulphate proteoglycans and the functional importance of their versatile interactions. In the second part, we summarize recent findings that have contributed to the characterization of heparanase-1, focusing on the molecular properties, working mechanism, substrate specificity, expression pattern, cellular activation and localization of this enzyme. Additionally, we review data implicating heparanase-1 in several normal and pathological processes, focusing on tumour metastasis and angiogenesis, and on evidence for a potentially direct signalling function of the molecule. In that context, we also briefly discuss heparanase-2, an intriguing close homologue of heparanase-1, for which, so far, no heparan sulphate-degrading activity could be demonstrated.

Brain heparanase expression is up-regulated during postnatal development and hypoxia-induced neovascularization in adult rats

Heparanase is an endo-beta-d-glucuronidase which specifically cleaves extracellular and cell surface heparan sulphates at intra-chain sites. Its enzymatic activity is strongly implicated in cell dissemination associated with tumor metastasis and inflammation. Indeed, heparanase gene is expressed in various tumors and its over-expression is correlated with increased tumor vascularity and metastatic potential of tumor cells. However, heparanase expression in non-invasive and non-immune tissue, including brain, has received less attention. Using RT-qPCR, western blot and histological analysis, we demonstrate in the adult rat that heparanase transcript is differentially expressed according to brain area, and that heparanase protein is mainly detected in neurons. Furthermore, we provide evidence that heparanase transcript and protein reach their greatest levels at early postnatal stages, in particular within the neocortex characterized by intensive structural plasticity. Using the in vitro model of PC12-induced neuronal differentiation, we suggest that developmental regulation of heparanase may coincide with axonal and dendritic pathfinding. At adulthood, we demonstrate that the increased heparanase transcript level correlates in the hippocampus with enhanced angiogenesis following repeated hypoxia exposures. Taken together, our results emphasize the potential importance of heparanase in brain homeostasis, both during development and adaptative responses to severe environmental challenges.

Analysis of the neoplastic nature and biological potential of sporadic and nevoid basal cell carcinoma syndrome-associated keratocystic odontogenic tumor

BACKGROUND

Keratocystic odontogenic tumor (KCOT), also known as odontogenic keratocyst, is a benign cystic neoplasm, which may be associated with nevoid basal cell carcinoma syndrome (NBCCS) and if it does, will occur as multiple cystic lesions. KCOT is locally destructive despite its bland histological features. However, the neoplastic nature of KCOT is not well established. Heparanase is an endo-d-glucuronidase enzyme that specifically cleaves heparan sulfate (HS) and the increase of its level in tumors promotes invasion, angiogenesis, and metastasis.

METHODS

To investigate the neoplastic character of KCOT, we studied the localization patterns of heparanase in KCOT, focusing on the differences between sporadic and NBCCS-associated KCOTs, by immunohistochemistry and in situ hybridization. To compare the expression pattern of these cysts with non-tumorous odontogenic developmental cyst, dentigerous cyst was included.

RESULTS

All the odontogenic cysts showed positive immunoreaction for heparanase protein in various intensities. The expression pattern of heparanase gene corresponded to that of protein expression. Interestingly, intense gene and protein expressions were observed in KCOT associated with NBCCS compared with sporadic ones and dentigerous cyst.

CONCLUSIONS

The results implied that heparanase expression may be correlated with the neoplastic properties of KCOT, particularly in NBCCS-associated cases.

Association of heparanase gene (HPSE) single nucleotide polymorphisms with hematological malignancies

Heparanase, endo-beta-D-glucuronidase, degrades heparan sulfate glycosaminoglycans - the principal polysaccharide of the basement membrane and extracellular matrix. Heparanase activity plays a decisive role in biological processes associated with remodeling of the extracellular matrix, such as cancer metastasis, angiogenesis and inflammation. In the hematopoietic system, heparanase is thought to be associated with normal differentiation and function of myeloid cells and platelets. We investigated heparanase polymorphisms in patients with acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), acute lymphoblastic leukemia (ALL), chronic myeloid leukemia (CML), Hodgkin's disease (HD) and multiple myeloma (MM). Significant correlation was found between rs11099592 and rs6535455 heparanase gene (HPSE) single nucleotide polymorphisms (SNPs) and ALL (chi2(1d.f.)=4.96, P=0.026). Genotype frequency comparisons revealed a significant association with rs4693602 (chi2(2d.f.)=7.276, P=0.026) in MM patients and rs4364254 (chi2(2d.f.)=6.226, P=0.044) in AML patients. Examination of HPSE gene mRNA expression by real-time RT-PCR indicated a significant low HPSE gene expression level in ALL patients and a high expression level in MM and AML patients, compared to healthy controls. Moreover, statistically significant correlation was found between heparanase mRNA expression level and three HPSE gene SNPs (rs4693608, rs11099592 and rs4364254) among healthy individuals. These data suggest that certain HPSE gene SNPs may contribute to basal heparanase gene expression and that alterations in this gene are an important determinant in the pathogenesis of ALL, AML and MM.

Translocation of heparanase into nucleus results in cell differentiation

We recently reported that heparanase, one of the extracellular matrix-degrading enzymes, which plays a critical role in cancer progression, is located not only in the cytoplasm but also in the nucleus. Here we identified nuclear translocation of heparanase as a key step in cell differentiation. We applied an in vitro differentiation model of HL-60 cells with 12-0-tetradecanoylphorbol-13-acetate (TPA), in which nuclear translocation of heparanase was observed using immunohistochemical analysis. In this system, nuclear translocation of heparanase was abolished by inhibitors of heat shock protein 90 (HSP90), suggesting the involvement of HSP90 in translocation of heparanase. We further confirmed that overexpression of active form of heparanase induced differentiation of HL-60 cells, although the catalytic negative form of heparanase did not. Therefore we speculate that nuclear translocation of enzymatically active heparanase may be involved in cellular differentiation. Our results suggest that a novel function of heparanase upon cell differentiation would raise a potential new strategy for cancer therapy of promyeloid leukemia and other types of cancer.

Heparanase localization and expression by head and neck cancer: correlation with tumor progression and patient survival

Heparanase is an endoglycosidase that specifically cleaves heparan sulfate (HS) side chains of HS proteoglycans, the major proteoglycans in the extracellular matrix and cell surfaces. Traditionally, heparanase activity was implicated in cellular invasion associated with angiogenesis, inflammation, and cancer metastasis. More recently, heparanase upregulation was documented in an increasing number of primary human tumors, correlating with reduced postoperative survival rate and enhanced tumor angiogenesis. In the present study, we examined the expression of heparanase in squamous cell carcinoma of the head and neck by means of immunostaining, and we correlated expression levels with patient outcome. The intensity and extent of heparanase staining correlated with tumor stage (P = .049 and P = .027, respectively), and the extent of staining further correlated with tumor grade (P = .047). Moreover, heparanase expression inversely correlated with patient status at the end of the study (P = .012). Notably, heparanase localization was found to be an important parameter for patient status. Thus, 63% of patients with nuclear staining, compared to 19% of patients with cytoplasmic staining (P = .0043), were alive, indicating that nuclear localization of the enzyme predicts a favorable outcome.