Role Of Heparanase Research Articles

Role of heparanase in pulmonary hypertension.

Pulmonary hypertension (PH) is a pathophysiological condition of increased pulmonary circulation vascular resistance due to various reasons, which mainly leads to right heart dysfunction and even death, especially in critically ill patients. Although drug interventions have shown some efficacy in improving the hemodynamics of PH patients, the mortality rate remains high. Hence, the identification of new targets and treatment strategies for PH is imperative. Heparanase (HPA) is an enzyme that specifically cleaves the heparan sulfate (HS) side chains in the extracellular matrix, playing critical roles in inflammation and tumorigenesis. Recent studies have indicated a close association between HPA and PH, suggesting HPA as a potential therapeutic target. This review examines the involvement of HPA in PH pathogenesis, including its effects on endothelial cells, inflammation, and coagulation. Furthermore, HPA may serve as a biomarker for diagnosing PH, and the development of HPA inhibitors holds promise as a targeted therapy for PH treatment.

Role of heparanase in sepsis‑related acute kidney injury (Review).

Sepsis-related acute kidney injury (S-AKI) is a common and significant complication of sepsis in critically ill patients, which can often only be treated with antibiotics and medications that reduce S-AKI symptoms. The precise mechanism underlying the onset of S-AKI is still unclear, thus hindering the development of new strategies for its treatment. Therefore, it is necessary to explore the pathogenesis of S-AKI to identify biomarkers and therapeutic targets for its early diagnosis and treatment. Heparanase (HPA), the only known enzyme that cleaves the side chain of heparan sulfate, has been widely studied in relation to tumor metabolism, procoagulant activity, angiogenesis, inflammation and sepsis. It has been reported that HPA plays an important role in the progression of S-AKI. The aim of the present review was to provide an overview of the function of HPA in S-AKI and to summarize its underlying molecular mechanisms, including mediating inflammatory response, immune response, autophagy and exosome biogenesis. It is anticipated that emerging discoveries about HPA in S-AKI will support HPA as a potential biomarker and therapeutic target to combat S-AKI.

Role of heparanase in ARDS through autophagy and exosome pathway (review).

Acute respiratory distress syndrome (ARDS) is the most common respiratory disease in ICU. Although there are many treatment and support methods, the mortality rate is still high. The main pathological feature of ARDS is the damage of pulmonary microvascular endothelium and alveolar epithelium caused by inflammatory reaction, which may lead to coagulation system disorder and pulmonary fibrosis. Heparanase (HPA) plays an significant role in inflammation, coagulation, fibrosis. It is reported that HPA degrades a large amount of HS in ARDS, leading to the damage of endothelial glycocalyx and inflammatory factors are released in large quantities. HPA can aggrandize the release of exosomes through syndecan-syntenin-Alix pathway, leading to a series of pathological reactions; at the same time, HPA can cause abnormal expression of autophagy. Therefore, we speculate that HPA promotes the occurrence and development of ARDS through exosomes and autophagy, which leads to a large amount of release of inflammatory factors, coagulation disorder and pulmonary fibrosis. This article mainly describes the mechanism of HPA on ARDS.

Abstract 2394: Activatable fluorogenic probe for two-photon imaging of heparanase in vivo

Abstract Heparanase, an endo-β-glucuronidase, is the only known enzyme that is responsible for the cleavage of heparan sulfate chains of heparan sulfate proteoglycans. Its enzymatic activity plays a key role in remodeling and degradation of the extracellular matrix, generation of biologically active carbohydrate fragments, and liberation of effector molecules, such as growth factors and chemokines, that are bound to the heparan sulfate side chains. Overexpression of heparanase has been implicated in most types of cancers and various inflammatory diseases that usually involve extensive heparan sulfate degradation and extracellular matrix remodeling. In particular, the role of heparanase in cancer is highly significant as it regulates multiple biological activities that fosters tumor progression, angiogenesis, metastases. Consequently, heparanase has been considered a biological target for various therapeutic applications including anti-cancer drug development. However, one of the major challenges in this research area is the development of robust and feasible heparanase probes to study the enzymes’ fundamental biology in the extracellular matrix, to provide heparanase-targeted diagnostics, and to aid in drug discovery efforts. Our lab has been developing various small-molecule-based heparanase activatable probes, and we have successfully developed chemical strategies that allow sensitive detection of heparanase activity in various contexts. Two-photon microscopy allows for deeper tissue penetration, excellent spatial resolution, and efficient light detection with reduced photobleaching effects. Herein, we extend our chemical strategies to develop a heparanase-activatable two-photon fluorogenic probe for real-time detection of heparanase activity in animal models of highly-aggressive brain cancer using two-photon imaging. Citation Format: Zachary Rabinowitz, Zhishen Wang, Johnathan Somers, Jun Liu, Joyce Jiang, Nina Zhang, Lina Cui. Activatable fluorogenic probe for two-photon imaging of heparanase in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2394.

Extracellular vesicles released during hypoxia transport heparanase and enhance macrophage migration, endothelial tube formation and cancer cell stemness

Heparanase is upregulated during the progression of most cancers and via its enzyme activity promotes extracellular matrix degradation, angiogenesis and cell migration. Heparanase expression is often associated with enhanced tumor aggressiveness and chemoresistance. We previously demonstrated that increased heparanase expression in tumor cells enhances secretion and alters the composition of tumor-released exosomes. In the present study, we discovered that extracellular vesicles (EVs) secreted by human multiple myeloma cells growing in hypoxic conditions exhibited elevated levels of heparanase cargo compared to EVs from cells growing in normoxic conditions. When macrophages (RAW 264.7 monocyte/macrophage-like cells) were exposed to EVs released by tumor cells growing in either hypoxic or normoxic conditions, macrophage migration and invasion was elevated by EVs from hypoxic conditions. The elevated invasion of macrophages was blocked by a monoclonal antibody that inhibits heparanase enzyme activity. Moreover, the heparanase-bearing EVs from hypoxic cells greatly enhanced endothelial cell tube formation consistent with the known role of heparanase in promoting angiogenesis. EVs from hypoxic tumor cells when compared with EVs from normoxic cells also enhanced cancer stemness properties of both CAG and RPMI 8226 human myeloma cells. Together these data indicate that under hypoxic conditions, tumor cells secrete EVs having an elevated level of heparanase as cargo. These EVs can act on both tumor and non-tumor cells, enhancing tumor progression and tumor cell stemness that likely supports chemoresistance and relapse of tumor.

Heparanase Contributes to Psoriatic Lesions Through Crosstalk with IL-17 Pathway.

Psoriasis is a chronic inflammatory disease that is considered by a network of immunocytes and cytokines. Among all, Th17 cells-derived IL-17 is a critical driving factor in the pathogenesis of psoriasis. Recently, disruption of the extracellular matrix was found to be related to psoriasis progression. In the present study, we aimed to investigate the role of heparanase (HPSE) in psoriasis and the crosstalk with the IL-17 signalling pathway. Skin tissues from non-affected areas and psoriatic lesion areas before and after 12 weeks of IL-17 monoclonal antibody treatment of 30 psoriasis patients were collected. HaCaT cells were treated with different concentrations of IL-17 antibody, and HPSE in cells and medium were measured with Western blotting assay as well as enzyme-linked immunosorbent assay (ELISA). In the imiquimod (IMQ)-induced psoriasis model, IL-17 protein and mRNA expression levels were measured, and changes in the proportion of Th17 cells were detected via flow cytometry. Our data showed that HPSE is upregulated in lesion tissues isolated from psoriasis patients, and was inhibited by anti-IL-17 treatment. In cutaneous cells and IMQ-induced psoriasis model, IL-17 promoted the synthesis of HPSE. Inversely, HPSE was also found to increase the percentage of Th17 cells derived from CD4+ T cells. Finally, we found that the combined treatments of HPSE inhibitor and IL-17 monoclonal antibody produced therapeutic effects on IMQ-induced psoriasis model. Our findings revealed the new role of HPSE in the pathogenesis of psoriasis and also provided a target for combined treatment of psoriasis.

Role of Heparanase and Syndecan-1 in HSV-1 Release from Infected Cells.

Herpes Simplex Virus 1 (HSV-1) is a neurotropic human virus that belongs to the Alphaherpesvirinae subfamily of Herpesviridae. Establishment of its productive infection and progression of disease pathologies depend largely on successful release of virions from the virus-producing cells. HSV-1 is known to exploit many host factors for its release. Recent studies have shown that heparanase (HPSE) is one such host enzyme that is recruited for this purpose. It is an endoglycosidase that cleaves heparan sulfate (HS) from the surface of infected cells. HS is a virus attachment coreceptor that is commonly found on cell surfaces as HS proteoglycans e.g., syndecan-1 (SDC-1). The current model suggests that HSV-1 during the late stage of infection upregulates HPSE, which in turn enhances viral release by removing the virus-trapping HS moieties. In addition to its role in directly enabling viral release, HPSE accelerates the shedding of HS-containing ectodomains of SDC-1, which enhances HSV-1 release via a similar mechanism by upregulating CREB3 and COPII proteins. This review outlines the role of HPSE and SDC-1 as newly assigned host factors that facilitate HSV-1 release during a lytic infection cycle.

Heparanase 2 (Hpa2) attenuates the growth of human sarcoma

The pro-tumorigenic properties of heparanase are well documented and established. In contrast, the role of heparanase 2 (Hpa2), a close homolog of heparanase, in cancer is not entirely clear. In carcinomas, Hpa2 is thought to attenuate tumor growth, possibly by inhibiting heparanase enzymatic activity. Here, we examine the role of Hpa2 in sarcoma, a group of rare tumors of mesenchymal origin, accounting for approximately 1% of all malignant tumors. Consistently, we found that overexpression of Hpa2 attenuates tumor growth while Hpa2 gene silencing results in bigger tumors. Mechanistically, attenuation of tumor growth by Hpa2 was associated with increased tumor stress conditions, involving ER stress, hypoxia, and JNK phosphorylation, leading to increased apoptotic cell death. In addition, overexpression of Hpa2 induces the expression of the p53 family member, p63 which, in sarcoma, functions to attenuate tumor growth. Moreover, we show that Hpa2 profoundly reduces stem cell characteristics of the sarcoma cells (stemness), most evident by failure of Hpa2 cells to grow as spheroids typical of cancer stem cells. Likewise, expression of CD44, a well-established cancer stem cell marker, was prominently decreased in Hpa2 cells. CD44 is also a cell surface receptor for hyaluronic acid (HA), a nonsulfated glycosaminoglycan that is enriched in connective tissues. Reduced expression of CD44 by Hpa2 may thus represent impaired cross-talk between Hpa2 and the extracellular matrix. Clinically, we found that Hpa2 is expressed by leiomyosarcoma tumor biopsies. Interestingly, nuclear localization of Hpa2 was associated with low-stage tumors. This finding opens a new direction in Hpa2 research.

Heparanase promotes endothelial-to-mesenchymal transition in diabetic glomerular endothelial cells through mediating ERK signaling

Glomerular endothelial cells (GEnCs) dysfunction occurs at the early stage of diabetic nephropathy (DN). One of its characteristics is endothelial-to-mesenchymal transition (EndMT). Heparanase (HPSE) is the only known mammalian endoglycosidase capable of degrading heparin sulfates and has a prominent role in DN pathogenesis. However, whether HPSE induces EndMT of GEnCs remains unknown. This study aimed to determine the effect and potential mechanism of HPSE on GEnCs phenotype under high-glucose conditions. In the early development of streptozotocin (STZ)-induced diabetic mice, HPSE overexpression was positively correlated with renal injury and the number of GEnCs undergoing EndMT, which was characterized by loss of endothelial marker CD31 and gain of mesenchymal markers including α-SMA and Snail1/2 by double immunofluorescence staining. Bioinformatics analysis revealed a positive correlation between HPSE and ERK. The counts of double positive staining of CD31 and p-ERK1/2 was significantly increased in the glomeruli of STZ-induced diabetic mice compared with sham mice. In cultured GEnCs, high glucose dramatically upregulated the expressions of HPSE and p-ERK1/2, both of which were markedly blocked by HPSE siRNA. Furthermore, recombinant mouse HPSE (rmHPSE) promoted the expressions of mesenchymal markers and p-ERK1/2 in a dosage- and time-dependent manner. U0126, a specific MEK/ERK inhibitor, significantly inhibited either high glucose or rmHPSE-induced EndMT of GEnCs. These data indicate that high glucose induces EndMT of GEnCs at least partially through upregulating HPSE and that HPSE promotes EndMT of GEnCs via activating ERK signaling. This study improves understanding the crucial role of HPSE in DN development and progression.

Histone H4 induces heparan sulfate degradation by activating heparanase in chlorine gas-induced acute respiratory distress syndrome

BackgroundHeparan sulfate (HS) degradation mediates pulmonary endothelial hyper-permeability and acute pulmonary edema during acute respiratory distress syndrome (ARDS). The aim of this study was to examine whether histone H4 induced HS degradation by activating heparanase (HPSE) in chlorine gas (Cl2)-induced ARDS.MethodsAcute lung injury was induced by Cl2 exposure or histone H4 injection in C57BL/6 mice. Histone H4 in bronchoalveolar lavage fluid (BALF) and plasma was measured by ELISA. HS degradation was measured by immunostaining, ELISA, and flow cytometry. HPSE mRNA and protein were measured by real-time qPCR and western blot analysis, respectively, at preset timepoints. The HPSE inhibitor OGT2115 and specific siRNAs were used to study the role of HPSE during HS degradation caused by Cl2 exposure or histone H4 challenge. Blocking antibodies against TLR1, TLR2, TLR4, or TLR6 were used in vitro to investigate which signaling pathway was involved. The transcriptional regulation of HPSE was studied vis-à-vis NF-κB, which was assessed by nuclear translocation of NF-κB p65 and phosphorylation of I-κBα protein.ResultsHistone H4 in BALF and plasma increased evidently after Cl2 inhalation. Cl2 exposure or histone H4 challenge caused obvious acute lung injury in mice, and the pulmonary glycocalyx was degraded evidently as observed from endothelial HS staining and measurement of plasma HS fragments. Pretreatment with OGT2115, an HPSE inhibitor, relieved the acute lung injury and HS degradation caused by Cl2 exposure or histone H4 challenge. Targeted knockdown of HPSE by RNA interference (RNAi) significantly inhibited histone H4 induced HS degradation in HPMECs, as measured by immunofluorescence and flow cytometry. By inducing phosphorylation of I-κB α and nuclear translocation of NF-κB p65, histone H4 directly promoted mRNA transcription and protein expression of HPSE in a dose-dependent manner. Additionally, a blocking antibody against TLR4 markedly inhibited both activation of NF-κB and expression of HPSE induced by histone H4.ConclusionsHistone H4 is a major pro-inflammatory mediator in Cl2-induced ARDS in mice, and induces HS degradation by activating HPSE via TLRs- and NF-κB-signaling pathways.

Role of Heparanase in Pulmonary Arterial Hypertension

Role of Heparanase in Pulmonary Arterial Hypertension

CMV Seropositive Status Increases Heparanase SNPs Regulatory Activity, Risk of Acute GVHD and Yield of CD34+ Cell Mobilization.

Heparanase is an endo-β-glucuronidase that is best known for its pro-cancerous effects but is also implicated in the pathogenesis of various viruses. Activation of heparanase is a common strategy to increase viral spread and trigger the subsequent inflammatory cascade. Using a Single Nucleotide Polymorphisms (SNP)-associated approach we identified enhancer and insulator regions that regulate HPSE expression. Although a role for heparanase in viral infection has been noticed, the impact of HPSE functional SNPs has not been determined. We investigated the effect of cytomegalovirus (CMV) serostatus on the involvement of HPSE enhancer and insulator functional SNPs in the risk of acute graft versus host disease (GVHD) and granulocyte-colony stimulating factor related CD34+ mobilization. A significant correlation between the C alleles of insulator rs4364254 and rs4426765 and CMV seropositivity was found in healthy donors and patients with hematological malignancies. The risk of developing acute GVHD after hematopoietic stem cell transplantation was identified only in CMV-seropositive patients. A significant correlation between the enhancer rs4693608 and insulator rs28649799 and CD34+ cell mobilization was demonstrated in the CMV-seropositive donors. It is thus conceivable that latent CMV infection modulates heparanase regulatory regions and enhances the effect of functional SNPs on heparanase function in normal and pathological processes.

Serum heparanase levels and left atrial/left atrial appendage thrombus in patients with nonvalvular atrial fibrillation.

Data regarding the possible role of heparanase (HPA) in the occurrence of left atrial/left atrial appendage (LA/LAA) thrombus in patients with atrial fibrillation (AF) is lacking. The goal of the present study was to assess the association between plasma levels of HPA and LA/LAA thrombus in AF. A total of 687patients with nonvalvular AF (NVAF) without anticoagulation therapy were included from January 2016 to June 2019. Serum HPA analysis was performed with acommercially available human ELISA kit. Logistic regression models were used to test for association. Serum HPA levels were significantly higher in patients with LA/LAA thrombus than in those without LA/LAA thrombus (270.8 [193.4 ± 353.2] pg/mL vs 150.3 [125.2 ± 208.4] pg/mL; P < 0.001). In multivariate analysis, serum HPA remained asignificantly independent predictor of LA/LAA thrombus (odds ratio 1.674, 95% confidence interval [CI] 1.339-2.289, P < 0.001). In the receiver operating characteristic (ROC) curve analysis, HPA showed apredictive value with an area under the curve (AUC) of 0.757 (95% CI 0.652-0.810, P < 0.001). The optimal cutoff level for HPA predicting LA/LAA thrombus was 210.7 pg/mL, with asensitivity of 74.3% and aspecificity of 64.8%. An elevated HPA level was associated with the presence of LA/LAA thrombus in patients with AF. HPA might portend the risk for the prothrombotic state in AF patients.

Role of heparanase 2 (Hpa2) in gastric cancer.

Heparanase is highly implicated in tumor metastasis due to its capacity to cleave heparan sulfate and, consequently, remodel the extracellular matrix underlying epithelial and endothelial cells. In striking contrast, only little attention was given to its close homolog, heparanase 2 (Hpa2), possibly because it lacks heparan sulfate-degrading activity typical of heparanase. We subjected sections of gastric carcinoma to immunostaining and correlated Hpa2 immunoreactivity with clinical records, including tumor grade, stage and patients' status. We over-expressed Hpa2 in gastric carcinoma cell lines and examined their tumorigenic properties in vitro and in vivo. We also evaluated the expression of Hpa2 by gastric carcinoma cells following inhibition of the proteasome, leading to proteotoxic stress, and the resulting signaling responsible for Hpa2 gene regulation. Here, we report that gastric cancer patients exhibiting high levels of Hpa2 survive longer. Similarly, mice administrated with gastric carcinoma cells engineered to over-express Hpa2 produced smaller tumors and survived longer than mice administrated with control cells. This was associated with increased phosphorylation of AMP-activated protein kinase (AMPK), a kinase that is situated at the center of a tumor suppressor network. We also found that MG132, an inhibitor of the proteasome that results in proteotoxic stress, prominently enhances Hpa2 expression. Notably, Hpa2 induction by MG132 appeared to be mediated by AMPK, and AMPK was found to induce the expression of Hpa2, thus establishing a loop that feeds itself where Hpa2 enhances AMPK phosphorylation that, in turn, induces Hpa2 expression, leading to attenuation of gastric tumorigenesis. These results indicate that high levels of Hpa2 in some tumors are due to stress conditions that tumors often experience due to their high rates of cell proliferation and high metabolic demands. This increase in Hpa2 levels by the stressed tumors appears critically important for patient outcomes.

Abstract 2112: Epigenetic control of heparanase expression using CRISPR/dCas9

Abstract Heparanase (HPSE) is the only known enzyme that cleaves the polymeric heparan sulfate (HS), a key component of the extracellular matrix (ECM). Heparanase has been implicated in various pathophysiological conditions involving ECM remodeling, such as tumor progression, metastasis angiogenesis, and inflammation. To study the role of heparanase in diseases, we developed a strategy to epigenetically modulate its expression in cells based on the clustered regularly interspaced short palindromic repeats (CRISPR) system. A fusion protein of dCAS9 can be directed to the HPSE gene via one or a combination of single guide RNAs. By linking dCas9 with different histone modification enzymes (eg. P300, hHDAC3, LSD1), the expression of heparanase can be up- or down-regulated through histone acetylation, deacetylation and demethylation. This approach allows us to tune heparanase expression in various cell lines on demand, enabling the study of heparanase activity in real-time. This work will also lead to novel therapeutics targeting heparanase. Citation Format: Zixin Chen, Guihua Zeng, Xiaogang Li, Fu-Sen Liang, Lina Cui. Epigenetic control of heparanase expression using CRISPR/dCas9 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2112.

Heparanase: a potential marker of worse prognosis in estrogen receptor-positive breast cancer

Heparanase promotes tumor growth in breast tumors. We now evaluated heparanase protein and gene-expression status and investigated its impact on disease-free survival in order to gain better insight into the role of heparanase in ER-positive (ER+) breast cancer prognosis and to clarify its role in cell survival following chemotherapy. Using pooled analysis of gene-expression data, we found that heparanase was associated with a worse prognosis in estrogen receptor-positive (ER+) tumors (log-rank p < 10−10) and predictive to chemotherapy resistance (interaction p = 0.0001) but not hormonal therapy (Interaction p = 0.62). These results were confirmed by analysis of data from a phase III, prospective randomized trial which showed that heparanase protein expression is associated with increased risk of recurrence in ER+ breast tumors (log-rank p = 0.004). In vitro experiments showed that heparanase promoted tumor progression and increased cell viability via epithelial–mesenchymal transition, stemness, and anti-apoptosis pathways in luminal breast cancer. Taken together, our results demonstrated that heparanase is associated with worse outcomes and increased cell viability in ER+ BC.

Heparanase overexpression impedes perivascular clearance of amyloid-\u03b2 from murine brain: relevance to Alzheimer\u2019s disease

Defective amyloid-β (Aβ) clearance from the brain is a major contributing factor to the pathophysiology of Alzheimer’s disease (AD). Aβ clearance is mediated by macrophages, enzymatic degradation, perivascular drainage along the vascular basement membrane (VBM) and transcytosis across the blood–brain barrier (BBB). AD pathology is typically associated with cerebral amyloid angiopathy due to perivascular accumulation of Aβ. Heparan sulfate (HS) is an important component of the VBM, thought to fulfill multiple roles in AD pathology. We previously showed that macrophage-mediated clearance of intracortically injected Aβ was impaired in the brains of transgenic mice overexpressing heparanase (Hpa-tg). This study revealed that perivascular drainage was impeded in the Hpa-tg brain, evidenced by perivascular accumulation of the injected Aβ in the thalamus of Hpa-tg mice. Furthermore, endogenous Aβ accumulated at the perivasculature of Hpa-tg thalamus, but not in control thalamus. This perivascular clearance defect was confirmed following intracortical injection of dextran that was largely retained in the perivasculature of Hpa-tg brains, compared to control brains. Hpa-tg brains presented with thicker VBMs and swollen perivascular astrocyte endfeet, as well as elevated expression of the BBB-associated water-pump protein aquaporin 4 (AQP4). Elevated levels of both heparanase and AQP4 were also detected in human AD brain. These findings indicate that elevated heparanase levels alter the organization and composition of the BBB, likely through increased fragmentation of BBB-associated HS, resulting in defective perivascular drainage. This defect contributes to perivascular accumulation of Aβ in the Hpa-tg brain, highlighting a potential role for heparanase in the pathogenesis of AD.

Heparanase 2 (Hpa2) attenuates tumor growth by inducing Sox2 expression

The pro-tumorigenic properties of heparanase are well documented, and heparanase inhibitors are being evaluated clinically as anti-cancer therapeutics. In contrast, the role of heparanase 2 (Hpa2), a close homolog of heparanase, in cancer is largely unknown. Previously, we have reported that in head and neck cancer, high levels of Hpa2 are associated with prolonged patient survival and decreased tumor cell dissemination to regional lymph nodes, suggesting that Hpa2 functions to restrain tumorigenesis. Also, patients with high levels of Hpa2 were diagnosed as low grade and exhibited increased expression of cytokeratins, an indication that Hpa2 promotes or maintains epithelial cell differentiation and identity. To reveal the molecular mechanism underlying the tumor suppressor properties of Hpa2, and its ability to induce the expression of cytokeratin, we employed overexpression as well as gene editing (Crispr) approaches, combined with gene array and RNAseq methodologies. At the top of the list of many genes found to be affected by Hpa2 was Sox2. Here we provide evidence that silencing of Sox2 resulted in bigger tumors endowed with reduced cytokeratin levels, whereas smaller tumors were developed by cells overexpressing Sox2, suggesting that in head and neck carcinoma, Sox2 functions to inhibit tumor growth. Notably, Hpa2-null cells engineered by Crispr/Cas 9, produced bigger tumors vs control cells, and rescue of Hpa2 attenuated tumor growth. These results strongly imply that Hpa2 functions as a tumor suppressor in head and neck cancer, involving Sox2 upregulation mediated, in part, by the high-affinity interaction of Hpa2 with heparan sulfate.

Heparanase, cell signaling, and viral infections.

Heparanase (HPSE) is a multifunctional protein endowed with many non-enzymatic functions and a unique enzymatic activity as an endo-β-d-glucuronidase. The latter allows it to serve as a key modulator of extracellular matrix (ECM) via a well-regulated cleavage of heparan sulfate side chains of proteoglycans at cell surfaces. The cleavage and associated changes at the ECM cause release of multiple signaling molecules with important cellular and pathological functions. New and emerging data suggest that both enzymatic as well as non-enzymatic functions of HPSE are important for health and illnesses including viral infections and virally induced cancers. This review summarizes recent findings on the roles of HPSE in activation, inhibition, or bioavailability of key signaling molecules such as AKT, VEGF, MAPK–ERK, and EGFR, which are known regulators of common viral infections in immune and non-immune cell types. Altogether, our review provides a unique overview of HPSE in cell-survival signaling pathways and how they relate to viral infections.

Heparanase Facilitates PMA-Induced Megakaryocytic Differentiation in K562 Cells via Interleukin 6/STAT3 Pathway.

Heparanase (HPSE) is an endo-β-D-glucuronidase that cleaves heparan sulfate and hence participates in remodeling of the extracellular matrix, leading to release of cytokines that are immobilized by binding to heparan sulfate proteoglycans (HSPGs), and consequently activating signaling pathways. This function of HPSE is correlated to its expression level that is normally very low in majority of the tissues. Exceptionally, human platelets express high level of HPSE, suggesting a unique physiological role in this cell. Using K562 cell line, we found a progressive increase of HPSE during the megakaryocytic differentiation. Analysis of a series of megakaryocytic differentiation-related heparin-binding proteins (HBPs) in the cell culture medium revealed an exclusive positive correlation between the level of interleukin 6 (IL-6) and HPSE expression. IL-6 modulated megakaryocytic differentiation through activation of STAT3. Further, we demonstrated that overexpression of HPSE potentiates megakaryocytic differentiation, whereas elimination of HPSE led to a delayed differentiation. This function of HPSE is associated with its activity, as overexpression of inactive HPSE had no effect on IL-6 production and megakaryocytic differentiation. The role of HPSE is further supported by the observation in an umbilical cord blood CD34+ cells megakaryocytic differentiation model. Our data propose a novel role for HPSE in platelets production by a HPSE/IL-6/STAT3 positive feedback loop that specifically regulates megakaryocytes maturation.