Macrophage activation by heparanase is mediated by TLR-2 and TLR-4 and associates with plaque progression.

OBJECTIVE: Factors and mechanisms that activate macrophages in atherosclerotic plaques are incompletely understood. We examined the capacity of heparanase to activate macrophages. METHODS AND RESULTS: Highly purified heparanase was added to mouse peritoneal macrophages and macrophage-like J774 cells, and the levels of tumor necrosis factor-α, matrix metalloproteinase-9, interlukin-1, and monocyte chemotactic protein-1 were evaluated by ELISA. Gene expression was determined by RT-PCR. Cells collected from Toll-like receptor-2 and Toll-like receptor-4 knockout mice were evaluated similarly. Heparanase levels in the plasma of patients with acute myocardial infarction, stable angina, and healthy subjects were determined by ELISA. Immunohistochemistry was applied to detect the expression of heparanase in control specimens and specimens of patients with stable angina or acute myocardial infarction. Addition or overexpression of heparanase variants resulted in marked increase in tumor necrosis factor-α, matrix metalloproteinase-9, interlukin-1, and monocyte chemotactic protein-1 levels. Mouse peritoneal macrophages harvested from Toll-like receptor-2 or Toll-like receptor-4 knockout mice were not activated by heparanase. Plasma heparanase level was higher in patients with acute myocardial infarction, compared with patients with stable angina and healthy subjects. Pathologic coronary specimens obtained from vulnerable plaques showed increased heparanase staining compared with specimens of stable plaque and controls. CONCLUSIONS: Heparanase activates macrophages, resulting in marked induction of cytokine expression associated with plaque progression toward vulnerability.

Elevated urine heparanase levels are associated with proteinuria and decreased renal allograft function.

Heparanase is an endo-ß-glucuronidase that cleaves heparan sulfate side chains, leading to structural modifications that loosen the extracellular matrix barrier and associated with tumor metastasis, inflammation and angiogenesis. In addition, the highly sulfated heparan sulfate proteoglycans are important constituents of the glomerular basement membrane and its permselective properties. Recent studies suggest a role for heparanase in several experimental and human glomerular diseases associated with proteinuria such as diabetes, minimal change disease, and membranous nephropathy. Here, we quantified blood and urine heparanase levels in renal transplant recipients and patients with chronic kidney disease (CKD), and assessed whether alterations in heparanase levels correlate with proteinuria and renal function. We report that in transplanted patients, urinary heparanase was markedly elevated, inversely associated with estimated glomerular filtration rate (eGFR), suggesting a relationship between heparanase and graft function. In CKD patients, urinary heparanase was markedly elevated and associated with proteinuria, but not with eGFR. In addition, urinary heparanase correlated significantly with plasma heparanase in transplanted patients. Such a systemic spread of heparanase may lead to damage of cells and tissues alongside the kidney.The newly described association between heparanase, proteinuria and decreased renal function is expected to pave the way for new therapeutic options aimed at attenuating chronic renal allograft nephropathy, leading to improved graft survival and patient outcome.

An assay to evaluate heparanase procoagulant activity.

BACKGROUND: Heparanase that was cloned from and is abundant in the placenta is implicated in cell invasion, tumor metastasis and angiogenesis. Recently, we demonstrated that heparanase is directly involved in the regulation of the hemostatic system. Heparanase was shown to form a complex and enhance tissue factor (TF) activity, resulting in increased factor Xa production (Nadir et al. Haematologica, 2010). The present work suggests a novel assay to evaluate heparanase procoagulant activity. METHODS: Heparanase procoagulant activity was studied using purified proteins of heparanase, TF, factor VIIa and factor X. The assay was verified in 55 plasma samples and compared to heparanase and tissue factor pathway inhibitor (TFPI) levels by ELISA and factor Xa, thrombin levels and antithrombin activity by chromogenic substrates. Thirty five samples were of third-trimester pregnant women (weeks 36-41) who were in labor or came for appointed elective cesarean section and 20 control samples were of non-pregnant healthy women. RESULTS: Heparanase procoagulant activity assay was shown to differentiate heparanase procoagulant effect from TF activity, in purified proteins. Heparanase procoagulant activity was significantly higher in the plasma of pregnant women compared to non-pregnant (p < 0.005). Heparanase relative contribution to the TF / heparanase complex activity was significantly higher in the plasma of pregnant women compared to non-pregnant (29% increase, p < 0.0001). Differences in heparanase procoagulant activity were more prominent than changes in heparanase levels by ELISA, TF activity, factor Xa, thrombin and free TFPI levels. CONCLUSIONS: Heparanase procoagulant activity can be determined by the suggested assay. The assay revealed a significant contribution of heparanase to the procoagulant state in late third-trimester pregnancy and at delivery.

Heparanase levels are elevated in the urine and plasma of type 2 diabetes patients and associate with blood glucose levels.

Heparanase is an endoglycosidase that specifically cleaves heparan sulfate side chains of heparan sulfate proteoglycans. Utilizing an ELISA method capable of detection and quantification of heparanase, we examined heparanase levels in the plasma and urine of a cohort of 29 patients diagnosed with type 2 diabetes mellitus (T2DM), 14 T2DM patients who underwent kidney transplantation, and 47 healthy volunteers. We provide evidence that heparanase levels in the urine of T2DM patients are markedly elevated compared to healthy controls (1162 ± 181 vs. 156 ± 29.6 pg/ml for T2DM and healthy controls, respectively), increase that is statistically highly significant (P<0.0001). Notably, heparanase levels were appreciably decreased in the urine of T2DM patients who underwent kidney transplantation, albeit remained still higher than healthy individuals (P<0.0001). Increased heparanase levels were also found in the plasma of T2DM patients. Importantly, urine heparanase was associated with elevated blood glucose levels, implying that glucose mediates heparanase upregulation and secretion into the urine and blood. Utilizing an in vitro system, we show that insulin stimulates heparanase secretion by kidney 293 cells, and even higher secretion is observed when insulin is added to cells maintained under high glucose conditions. These results provide evidence for a significant involvement of heparanase in diabetic complications.

The heparanase system and tumor metastasis: is heparanase the seed and soil?

Tumor metastasis, the leading cause of cancer patients' death, is still insufficiently understood. While concepts and mechanisms of tumor metastasis are evolving, it is widely accepted that cancer metastasis is accompanied by orchestrated proteolytic activity executed by array of proteases. While matrix metalloproteinases (MMPs) attracted much attention, other proteases constitute the tumor milieu, of which a large family consists of cysteine proteases named cathepsins. Like MMPs, some cathepsins are often upregulated in cancer and, once secreted or localized to the cell surface, can degrade components of the extracellular matrix. In addition, cathepsin L is held responsible for processing and activation of heparanase, an endo-ß-glucuronidase capable of cleaving heparan sulfate side chains of heparan sulfate proteoglycans, activity that is strongly implicated in cell dissemination associated with tumor metastasis, angiogenesis, and inflammation. In this review, we discuss recent progress in heparanase research focusing on heparanase-related molecules namely, cathepsin L and heparanase 2 (Hpa2), a heparanase homolog.

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.

Heparanase enhances the generation of activated factor X in the presence of tissue factor and activated factor VII.

BACKGROUND: Heparanase is an endo-ß-D-glucuronidase dominantly involved in tumor metastasis and angiogenesis. Recently, we demonstrated that heparanase is involved in the regulation of the hemostatic system. Our hypothesis was that heparanase is directly involved in activation of the coagulation cascade. DESIGN AND METHODS: Activated factor X and thrombin were studied using chromogenic assays, immunoblotting and thromboelastography. Heparanase levels were measured by enzyme-linked immunosorbent assay. A potential direct interaction between tissue factor and heparanase was studied by co-immunoprecipitation and far-western assays. RESULTS: Interestingly, addition of heparanase to tissue factor and activated factor VII resulted in a 3- to 4-fold increase in activation of the coagulation cascade as shown by increased activated factor X and thrombin production. Culture medium of human embryonic kidney 293 cells over-expressing heparanase and its derivatives increased activated factor X levels in a non-enzymatic manner. When heparanase was added to pooled normal plasma, a 7- to 8-fold increase in activated factor X level was observed. Subsequently, we searched for clinical data supporting this newly identified role of heparanase. Plasma samples from 35 patients with acute leukemia at presentation and 20 healthy donors were studied for heparanase and activated factor X levels. A strong positive correlation was found between plasma heparanase and activated factor X levels (r=0.735, P=0.001). Unfractionated heparin and an inhibitor of activated factor X abolished the effect of heparanase, while tissue factor pathway inhibitor and tissue factor pathway inhibitor-2 only attenuated the procoagulant effect. Using co-immunoprecipitation and far-western analyses it was shown that heparanase interacts directly with tissue factor. CONCLUSIONS: Overall, our results support the notion that heparanase is a potential modulator of blood hemostasis, and suggest a novel mechanism by which heparanase increases the generation of activated factor X in the presence of tissue factor and activated factor VII.

Selective autoantibody production against CCL3 is associated with human type 1 diabetes mellitus and serves as a novel biomarker for its diagnosis.

We have recently demonstrated that patients suffering from chronic autoimmune diseases develop an autoantibody response against key mediators that participate in the initiation and progression of these diseases. In this paper, we show that patients with type 1 diabetes mellitus (T1DM), but not those suffering from several other inflammatory autoimmune diseases, display a selective autoantibody titer to a single CC chemokine named CCL3. From the diagnostic point we show that this response could be used as a biomarker for diagnosis of T1DM, a disease that is currently diagnosed by autoantibodies to competitive anti-insulin Abs, islet cell Abs, and glutamic acid decarboxylase Abs. We show that our currently suggested biomarker is more reliable than each of the above alone, including diagnosis of T1DM at its preclinical stage, and could therefore be used as a novel way for diagnosis of T1DM. These Abs were found to be neutralizing Abs. It is possible, though hard to prove, that these Abs participate in the natural regulation of the human disease. Hence, it has previously been shown by others that selective neutralization of CCL3 suppresses T1DM in NOD mice. Theses results together with ours suggest CCL3 as a preferential target for therapy of T1DM.

Inverse correlation between HPSE gene single nucleotide polymorphisms and heparanase expression: possibility of multiple levels of heparanase regulation.

Heparanase is an endo-beta-glucuronidase that specifically cleaves the saccharide chains of heparan sulfate proteoglycans. Heparanase plays important roles in processes such as angiogenesis, tumor metastasis, tissue repair and remodeling, inflammation and autoimmunity. Genetic variations of the heparanase gene (HPSE) have been associated with heparanase transcription level. The present study was undertaken to identify haplotype or single nucleotide polymorphisms (SNPs) genotype combinations that correlate with heparanase expression both at the mRNA and protein levels. For this purpose, 11 HPSE gene SNPs were genotyped among 108 healthy individuals. Five out of the eleven polymorphisms revealed an association between the SNPs and heparanase expression. SNP rs4693608 exhibited a strong evidence of association. Analysis of haplotypes distribution revealed that the combination of two SNPs (rs4693608 and rs4364254) disclosed the most significant result. This approach allowed segregation of possible genotype combinations to three groups that correlate with low (LR: GG-CC, GG-CT, GG-TT, GA-CC), intermediate (MR: GA-CT, GA-TT) and high (HR: AA-TT, AA-CT) heparanase expression. Unexpectedly, LR genotype combinations were associated with low mRNA expressions level and high heparanase concentration in plasma, while HR genotype combinations were associated with high expression of mRNA and low plasma protein level. Because the main site of activity of secreted active heparanase is the extracellular matrix and cell surface, the origin and functional significance of plasma heparanase remain to be investigated. The current study indicates that rs4693608 and rs4364254 SNPs are involved in the regulation of heparanase expression and provides the basis for further studies on the association between HPSE gene SNPs and disease outcome.

Plasma heparanase as a significant marker of treatment response in children with Hodgkin lymphoma: pilot study.

INTRODUCTION: The aim of this pilot study was to determine heparanase plasma levels (HP) at diagnosis and at restaging in children diagnosed with Hodgkin lymphoma and to investigate whether this parameter provides prognostic information for response to treatment after induction therapy. PATIENTS AND METHODS: HP levels of 19 pediatric patients (mean age: 10.3 years (y) (range, 4-18 y), 9 girls, 10 boys) with Hodgkin lymphoma were assayed at diagnosis and at restaging. HP levels were determined using an ELISA anti-human heparanase immunoassay kit. According to diagnosis, CAT scan and/or FDG/ PET-CT fusion were performed to assess response to treatment after 2-3 courses of chemotherapy. Two patients received VAMP protocol (1 stage IA, 1 stage IIA), 1 received AV-PC (nonbulky stage IIA), 4 received COPP/ABV (3 stage IIA bulky, 1 stage IIIA nonbulky), 4 received ABVE-PC (2 stage IIB, 1 stage IIA bulky, 1 stage IIIA bulky), 2 received ABVD (1 stage IIA bulky, 1 stage IIIA), and 6 received escalated BEACOPP (1 stage IIIB, 3 stage IVA, 2 stage IVB). RESULTS: Changes in HP levels were found to correlate with response to treatment for most of the children. At diagnosis, average HP level was 1019 pg/mL (range, 141-5733 pg/mL), decreasing at restaging to 588 pg/mL (range, 62-3267 pg/mL) (p = .034). At diagnosis, the average HP of the 16 patients in CR or VGPR was 1104 pg/mL; it had decreased at restaging to 586 pg/mL (p = .032). At diagnosis, the average HP level for the 3 patients with TP or PR was 1704 pg/mL; it had increased to 1938 pg/mL at restaging (p = .166). Due to the small number of patients, no correlation was observed between HP levels at diagnosis, staging, or any other clinical prognostic factor. CONCLUSIONS: Changes in plasma HP levels correlated with response to treatment for children diagnosed with Hodgkin lymphoma. This provides a rationale for exploring clinical interest in plasma heparanase measurements of a larger group, using the test for clinical trials of antiangiogenic therapies.

Alternatively spliced Spalax heparanase inhibits extracellular matrix degradation, tumor growth, and metastasis.

Heparanase is an endoglycosidase that degrades heparan sulfate (HS) at the cell surface and in the extracellular matrix. Heparanase is expressed mainly by cancer cells, and its expression is correlated with increased tumor aggressiveness, metastasis, and angiogenesis. Here, we report the cloning of a unique splice variant (splice 36) of heparanase from the subterranean blind mole rat (Spalax). This splice variant results from skipping part of exon 3, exons 4 and 5, and part of exon 6 and functions as a dominant negative to the wild-type enzyme. It inhibits HS degradation, suppresses glioma tumor growth, and decreases experimental B16-BL6 lung colonization in a mouse model. Intriguingly, Spalax splice variant 7 of heparanase (which results from skipping of exon 7) is devoid of enzymatic activity, but unlike splice 36 it enhances tumor growth. Our results demonstrate that alternative splicing of heparanase regulates its enzymatic activity and might adapt the heparanase function to the fluctuating normoxic-hypoxic subterranean environment that Spalax experiences. Development of anticancer drugs designed to suppress tumor growth, angiogenesis, and metastasis is a major challenge, of which heparanase inhibition is a promising approach. We anticipate that the heparanase splicing model, evolved during 40 million years of Spalacid adaptation to underground life, would pave the way for the development of heparanase-based therapeutic modalities directed against angiogenesis, tumor growth, and metastasis.

Heparanase: one molecule with multiple functions in cancer progression.

Mammalian heparanase, an endoglycosidase-degrading heparan sulfate, is synthesized as a latent 65 kDa precursor that undergoes proteolytic processing, primarily by cathepsin-L, yielding 8 kDa and 50 kDa subunits that heterodimerize to form a highly active enzyme. Enhanced heparanase expression in human tumors correlates with metastatic potential, tumor vascularity, and reduced postoperative survival of cancer patients, attributed to enzymatic and nonenzymatic activities of the heparanase protein. Urinary and plasma levels of heparanase are elevated in cancer patients and suppressed in response to effective anticancer treatments. These observations and the anticancerous effect of heparanase gene silencing and of heparanase-inhibiting molecules suggest that the enzyme is a promising target for anticancer drug development.

Heparanase regulates retention and proliferation of primitive Sca-1+/c-Kit+/Lin- cells via modulation of the bone marrow microenvironment.

Heparanase is involved in tumor growth and metastasis. Because of its unique cleavage of heparan sulfate, which binds cytokines, chemokines and proteases, we hypothesized that heparanase is also involved in regulation of early stages of hematopoiesis. We report reduced numbers of maturing leukocytes but elevated levels of undifferentiated Sca-1(+)/c-Kit(+)/Lin(-) cells in the bone marrow (BM) of mice overexpressing heparanase (hpa-Tg). This resulted from increased proliferation and retention of the primitive cells in the BM microenvironment, manifested in increased SDF-1 turnover. Furthermore, heparanase overexpression in mice was accompanied by reduced protease activity of MMP-9, elastase, and cathepsin K, which regulate stem and progenitor cell mobilization. Moreover, increased retention of the progenitor cells also resulted from up-regulated levels of stem cell factor (SCF) in the BM, in particular in the stem cell-rich endosteum and endothelial regions. Increased SCF-induced adhesion of primitive Sca-1(+)/c-Kit(+)/Lin(-) cells to osteoblasts was also the result of elevation of the receptor c-Kit. Regulation of these phenomena is mediated by hyperphosphorylation of c-Myc in hematopoietic progenitors of hpa-Tg mice or after exogenous heparanase addition to wildtype BM cells in vitro. Altogether, our data suggest that heparanase modification of the BM microenvironment regulates the retention and proliferation of hematopoietic progenitor cells.

Clinical significance of urine heparanase in bladder cancer progression.

Heparanase is an endo-beta-glucuronidase capable of cleaving heparan sulfate (HS), an activity implicated in tumor metastasis. Heparanase expression is upregulated in primary human tumors, correlating with reduced post operative survival and elevated microvessel density. An ELISA method was used to quantify heparanase in urine from 282 individuals. Urine was collected from healthy volunteers (n = 41), patients diagnosed with noncancerous pathologic disorders (n = 90), and bladder cancer patients (n = 92). Fifty-nine bladder carcinoma patients after transurethral resection (TUR) with no evidence of disease (NED) were also included. Heparanase levels were significantly elevated in urine from bladder cancer patients compared with healthy controls (P < .001) and with noncancerous urinary disorders (P < .05). Heparanase elevation strongly correlated with tumor grade (P < .001) and stage (P = .027). An optimal cutoff value of 154 pg/ml was determined. Of 199 individuals enrolled (59 patients after TUR and 24 patients with recurring disease were excluded), 65 had heparanase levels above 154 pg/ml. Only 3 of 65 (4.6%) were healthy individuals. In contrast, 52.3% (34 of 65) of individuals with heparanase levels above 154 pg/ml were bladder cancer patients. The results indicate that urine heparanase levels are elevated during bladder cancer progression, suggesting that the ELISA method may be applied for bladder cancer diagnosis.

Low and high affinity receptors mediate cellular uptake of heparanase.

Heparanase is an endoglycosidase which cleaves heparan sulfate and hence participates in degradation and remodeling of the extracellular matrix. Importantly, heparanase activity 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. Heparanase has been characterized as a glycoprotein, yet glycan biochemical analysis was not performed to date. Here, we applied the Qproteometrade mark GlycoArray kit to perform glycan analysis of heparanase, and compared the kit results with the more commonly used biochemical analyses. We employed fibroblasts isolated from patients with I-cell disease (mucolipidosis II), fibroblasts deficient of low density lipoprotein receptor-related protein and fibroblasts lacking mannose 6-phosphate receptor, to explore the role of mannose 6-phosphate in heparanase uptake. Iodinated heparanase has been utilized to calculate binding affinity. We provide evidence for hierarchy of binding to cellular receptors as a function of heparanase concentration. We report the existence of a high affinity, low abundant (i.e., low density lipoprotein receptor-related protein, mannose 6-phosphate receptor), as well as a low affinity, high abundant (i.e., heparan sulfate proteoglycan) receptors that mediate heparanase binding, and suggest that these receptors co-operate to establish high affinity binding sites for heparanase, thus maintaining extracellular retention of the enzyme tightly regulated.

Heparanase levels are elevated in the plasma of pediatric cancer patients and correlate with response to anticancer treatment.

Heparanase is an endoglycosidase that specifically cleaves heparan sulfate (HS) side chains of heparan sulfate proteoglycans, the major proteoglycan in the extracellular matrix (ECM) and cell surfaces. Heparanase upregulation was documented in an increasing number of primary human tumors, correlating with reduced postoperative survival rate and enhanced tumor angiogenesis. The purpose of the current study was to determine heparanase levels in blood samples collected from pediatric cancer patients using an ELISA method. Heparanase levels were elevated four-fold in the plasma of cancer patients compared with healthy controls (664 +/- 143 vs 163 +/- 18 pg/ml, respectively). Evaluating plasma samples following anticancer therapy revealed reduced heparanase levels (664 +/- 143 vs 429 +/- 82 pg/ml), differences that are statistically highly significant (P = .0048). Of the 55 patients with complete remission (CR) or very good partial remission (VGPR) at restaging, 41 (74.5%) had lower heparanase amounts, whereas 14 patients (25.5%) had similar or higher amounts of plasma heparanase. All nine patients with stable or advancing disease had similar or elevated levels of heparanase on restaging. The results show that heparanase levels are elevated in the plasma of pediatric cancer patients and closely correlate with treatment responsiveness, indicating that heparanase levels can be used to diagnose and monitor patient's response to anticancer treatment.

Heparanase up-regulation in tongue cancer: tissue and saliva analysis.

BACKGROUND: Heparanase up-regulation has been correlated with reduced postoperative survival in various cancers. METHODS: Heparanase expression was analyzed in 60 consenting tongue (mobile) cancer patients by means of immunohistochemistry. Heparanase levels were also analyzed in the saliva of both healthy controls and tongue cancer patients using a novel heparanase enzyme-linked immunosorbent assay method. RESULTS: Heparanase staining was positive (>0) in 92% and negative (=0) in 8% of the tumors and staining intensity correlated with tumor size and tumor stage. Moreover, the survival probability of patients negative for heparanase (=0) at 60 months was 100%, compared with only 41% for patients positive for heparanase (>0), suggesting that heparanase may serve as a prognostic factor for this malignancy and an attractive target for anticancer drug development. Heparanase was detected in the saliva of healthy controls and the mean concentration was determined as 119 +/- 37 pg/mL. Importantly, a nearly 3-fold increase of heparanase levels was detected in saliva collected from tongue cancer patients (334 +/- 69 pg/mL), a difference that is statistically highly significant (P = .004). CONCLUSIONS: These findings support heparanase up-regulation in tongue cancer and raise the possibility of using this simple test as a diagnostic tool to monitor tongue cancer progression and response to treatment.

Age-related changes in salivary antioxidant profile: possible implications for oral cancer.

Oral cancer's much higher prevalence among older people may be due to an age-related reduction in protective salivary antioxidant mechanisms and/or an age-related increase in the magnitude of oral carcinogen attack, such as reactive oxygen species (ROS) and reactive nitrogen species (RNS), causing DNA aberrations. This study found a significantly reduced total value of salivary antioxidant capacity in elderly persons (as measured by overall antioxidant capacity [ImAnOx] assay), (46% of healthy individuals, p =.004), increased oxidative stress (86% increase in carbonyl concentrations--indicators of enhanced ROS attack, p =.001), and increased salivary concentrations and total values of RNS (7-fold and 3-fold higher respectively, p =.001), all contributing to increased DNA oxidation of oral epithelial cells. Salivary oxidative stress-related changes in the intimately related saliva and oral epithelium compounded with higher viscosity of saliva may explain the higher prevalence of oral cancer in the elderly population. Administration of local therapeutic agents (i.e., antioxidants) to the oral cavity should be considered.

Characterization of mechanisms involved in secretion of active heparanase.

Heparanase is an endo-beta-D-glucuronidase involved in extracellular matrix remodeling and degradation and implicated in tumor metastasis, angiogenesis, inflammation, and autoimmunity. The enzyme is synthesized as a latent 65-kDa protein and is processed in the lysosomal compartment to an active 58-kDa heterodimer, where it is stored in a stable form. In contrast, its heparan sulfate substrate is localized extracellularly, suggesting the existence of mechanisms that trigger heparanase secretion. Here we show that secretion of the active enzyme is mediated by the protein kinase A and C pathways. Moreover, secretion of active heparanase was observed upon cell stimulation with physiological concentrations of adenosine, ADP, and ATP, as well as by the noncleavable ATP analogue adenosine 5'-O-(thiotriphosphate). Indeed, heparanase secretion was noted upon cell stimulation with a specific P2Y1 receptor agonist and was inhibited by P2Y receptor antagonists. The kinetics of heparanase secretion resembled the secretion of cathepsin D, a lysosomal enzyme, indicating that the secreted heparanase is of lysosomal origin. We suggest that secretion of active heparanase is initiated by extracellular cues activating the protein kinase A and C signaling pathways. The secreted enzyme(s) then facilitate cell invasion associated with cancer metastasis, angiogenesis, and inflammation.

An ELISA method for the detection and quantification of human heparanase.

Heparanase is a mammalian endo-beta-D-glucuronidase that cleaves heparan sulfate side chains at a limited number of sites. Heparanase enzymatic activity is thought to participate in degradation and remodeling of the extracellular matrix and to facilitate cell invasion associated with tumor metastasis, angiogenesis, and inflammation. Traditionally, heparanase activity was well correlated with the metastatic potential of a large number of tumor-derived cell types. More recently, heparanase upregulation was detected in an increasing number of primary human tumors, correlating, in some cases, with poor postoperative survival and increased tumor vascularity. The present study was undertaken to develop a highly sensitive ELISA suitable for the determination and quantification of human heparanase in tissue extracts and body fluids. The assay preferentially detects the 8+50 kDa active heparanase heterodimer vs. the latent 65 kDa proenzyme and correlates with immunoblot analysis of heparanase containing samples. It detects heparanase at concentrations as low as 200 pg/ml and is suitable for quantification of heparanase in tissue extracts and urine.