Heparanase: A Challenging Cancer Drug Target

Impact of heparanase-2 (Hpa2) on cancer and inflammation: Advances and paradigms

HPSE2, the gene-encoding heparanase 2 (Hpa2), is mutated in urofacial syndrome (UFS), a rare autosomal recessive congenital disease attributed to peripheral neuropathy. Hpa2 lacks intrinsic heparan sulfate (HS)-degrading activity, the hallmark of heparanase (Hpa1), yet it exhibits a high affinity toward HS, thereby inhibiting Hpa1 enzymatic activity. Hpa2 regulates selected genes that promote normal differentiation, tissue homeostasis, and endoplasmic reticulum (ER) stress, resulting in antitumor, antiangiogenic, and anti-inflammatory effects. Importantly, stress conditions induce the expression of Hpa2, thus establishing a feedback loop, where Hpa2 enhances ER stress which, in turn, induces Hpa2 expression. In most cases, cancer patients who retain high levels of Hpa2 survive longer than patients bearing Hpa2-low tumors. Experimentally, overexpression of Hpa2 attenuates the growth of tumor xenografts, whereas Hpa2 gene silencing results in aggressive tumors. Studies applying conditional Hpa2 knockout (cHpa2-KO) mice revealed an essential involvement of Hpa2 contributed by the host in protecting against cancer and inflammation. This was best reflected by the distorted morphology of the Hpa2-null pancreas, including massive infiltration of immune cells, acinar to adipocyte trans-differentiation, and acinar to ductal metaplasia. Moreover, orthotopic inoculation of pancreatic ductal adenocarcinoma (PDAC) cells into the pancreas of Hpa2-null vs. wild-type mice yielded tumors that were by far more aggressive. Likewise, intravenous inoculation of cancer cells into cHpa2-KO mice resulted in a dramatically increased lung colonization reflecting the involvement of Hpa2 in restricting the formation of a premetastatic niche. Elucidating Hpa2 structure-activity-relationships is expected to support the development of Hpa2-based therapies against cancer and inflammation.

A biological guide to glycosaminoglycans: current perspectives and pending questions

Mammalian glycosaminoglycans (GAGs), except hyaluronan (HA), are sulfated polysaccharides that are covalently attached to core proteins to form proteoglycans (PGs). This article summarizes key biological findings for the most widespread GAGs, namely HA, chondroitin sulfate/dermatan sulfate (CS/DS), keratan sulfate (KS), and heparan sulfate (HS). It focuses on the major processes that remain to be deciphered to get a comprehensive view of the mechanisms mediating GAG biological functions. They include the regulation of GAG biosynthesis and postsynthetic modifications in heparin (HP) and HS, the composition, heterogeneity, and function of the tetrasaccharide linkage region and its role in disease, the functional characterization of the new PGs recently identified by glycoproteomics, the selectivity of interactions mediated by GAG chains, the display of GAG chains and PGs at the cell surface and their impact on the availability and activity of soluble ligands, and on their move through the glycocalyx layer to reach their receptors, the human GAG profile in health and disease, the roles of GAGs and particular PGs (syndecans, decorin, and biglycan) involved in cancer, inflammation, and fibrosis, the possible use of GAGs and PGs as disease biomarkers, and the design of inhibitors targeting GAG biosynthetic enzymes and GAG-protein interactions to develop novel therapeutic approaches.

Heparanase interacting BCLAF1 to promote the development and drug resistance of ICC through the PERK/eIF2α pathway

Intrahepatic cholangiocarcinoma (ICC) is a primary epithelial carcinoma known for its aggressive nature, high metastatic potential, frequent recurrence, and poor prognosis. Heparanase (HPSE) is the only known endogenous β-glucuronidase in mammals. In addition to its well-established enzymatic roles, HPSE critically exerts non-catalytic function in tumor biology. This study herein aimed to investigate the non-enzymatic roles of HPSE as well as relevant regulatory mechanisms in ICC. Our results demonstrated that HPSE was highly expressed in ICC and promoted the proliferation of ICC cells, with elevated HPSE levels implicating a poor overall survival of ICC patients. Notably, HPSE interacted with Bcl-2-associated factor 1 (BCLAF1) to upregulate the expression of Bcl-2, which subsequently activated the PERK/eIF2α-mediated endoplasmic reticulum (ER) stress pathway to promote anti-apoptotic effect of ICC. Moreover, our in vivo experiments revealed that concomitant administration of gemcitabine and the Bcl-2 inhibitor navitoclax enhanced the sensitivity of ICC cells with highly expressed HPSE to chemotherapy. In summary, our findings revealed that HPSE promoted the development and drug resistance of ICC via its non-enzymatic function. Bcl-2 may be considered as an effective target with therapeutic potential to overcome ICC chemotherapy resistance induced by HPSE, presenting valuable insights into the development of novel therapeutic strategies against ICC.

Investigation of inhibitory effect of sulfated chitosan oligomer on human heparanase enzyme: in silico and in vitro studies

Deaths from cancer are widespread worldwide and the numbers continue to increase day by day. During the disease progression of cancer in cells, many of its metabolic activities change. Increased heparanase enzyme release is just one example. Following heparanase enzyme activity, many molecules interact with the remodeling of glycosaminoglycan structures, which triggers the release of different enzymes, cytokines, and growth factors, including fibroblast growth factors (FGF1 and FGF2), vascular endothelial growth factor (VEGF), hepatocyte growth factor, transforming growth factor β and platelet-derived growth factor. These are the most important factors in metastasis due to the formation of new vascular structures caused by those elements. To reduce tumor growth and metastasis, various drugs have been designed by modifying chitosan and its derivatives. In this study, we used chitosan oligomer (A), sulfated chitosan oligomer (ShCsO) (B), heparin (C), phosphate monomer (D1) of PI-88 and sulfate monomer (D2) of PI-88 as heparanase inhibitors. We modified the chitosan oligomer with chlorosulfonic acid to synthesize ShCsO to investigate its inhibitory effects on human serum heparanase. Also examined were molecular docking; molecular dynamics (MD); adsorption, distribution, metabolism, elimination and toxicity (ADMET); and target prediction. ShCsO decreased enzyme activity at a concentration of 0.0001 mg/mL. The docking scores of A, B and C from in silico studies were -6.254, -6.936 and -6.980 kcal/mol, respectively, and the scores for the two different PI-88 monomers were -5.741 and -5.824 kcal/mol. These results show that ShCsO may be a potential drug candidate for treating cancer.Communicated by Ramaswamy H. Sarma.

Overcoming intestinal barriers by heparanase-responsive charge-converting nanocarriers

In this study, we present a novel approach for overcoming intestinal barriers by utilizing heparanase-responsive charge-converting nanocarriers (NCs). These NCs are designed to undergo charge conversion in response to the activity of heparanase (HPSE), an enzyme commonly overexpressed in cancer cells. Nanostructured lipid carriers (NLCs) and solid lipid nanocarriers (SLNs) with a positively charged core were coated with heparin (Hep), resulting in a negative surface charge and a size between 195 and 220 nm. However, upon encountering heparanase, heparin undergoes enzymatic cleavage, resulting in zeta potential shift from -22.1 to +8.3 mV for NLC-Hep and from -19.8 to +5.1 mV for SLN-Hep. Heparin-coated NCs showed more than 6-fold higher mucus permeating properties compared to the uncoated NCs. In vitro experiments using the heparanase-expressing cancer cell line HT29 demonstrated an up to 4-fold improved cellular uptake of the heparin coated NCs compared to co-incubation with the HPSE inhibitor suramin. Furthermore, cellular uptake was investigated on Caco-2 cells and on a Caco-2/HT29-MTX co-culture. Overall, this study highlights the potential of heparanase-responsive charge-converting NCs as a promising strategy for overcoming intestinal barriers and enhancing cellular uptake.

An overview of extracellular matrix and its remodeling in the development of cancer and metastasis with a glance at therapeutic approaches

The extracellular matrix (ECM) is an inevitable part of tissues able to provide structural support for cells depending on the purpose of tissues and organs. The dynamic characteristics of ECM let this system fluently interact with the extrinsic triggers and get stiffed, remodeled, and/or degraded ending in maintaining tissue homeostasis. ECM could serve as the platform for cancer progression. The dysregulation of biochemical and biomechanical ECM features might take participate in some pathological conditions such as aging, tissue destruction, fibrosis, and particularly cancer. Tumors can reprogram how ECM remodels by producing factors able to induce protein synthesis, matrix proteinase expression, degradation of the basement membrane, growth signals and proliferation, angiogenesis, and metastasis. Therefore, targeting the ECM components, their secretion, and their interactions with other cells or tumors could be a promising strategy in cancer therapies. The present study initially introduces the physiological functions of ECM and then discusses how tumor-dependent dysregulation of ECM could facilitate cancer progression and ends with reviewing the novel therapeutic strategies regarding ECM.

Extracellular Vesicles: Biological Packages That Modulate Tumor Cell Invasion

Tumor progression, from early-stage invasion to the formation of distal metastases, relies on the capacity of tumor cells to modify the extracellular matrix (ECM) and communicate with the surrounding stroma. Extracellular vesicles (EVs) provide an important means to regulate cell invasion due to the selective inclusion of cargoes such as proteases and matrix proteins into EVs that can degrade or modify the ECM. EVs have also been shown to facilitate intercellular communication in the tumor microenvironment through paracrine signaling, which can impact ECM invasion by cancer cells. Here, we describe the current knowledge of EVs as facilitators of tumor invasion by virtue of their effects on proteolytic degradation and modification of the ECM, their ability to educate the stromal cells in the tumor microenvironment, and their role as mediators of long-range communication aiding in cell invasion and matrix remodeling at secondary sites.

Synthetic Heparanase Inhibitors Can Prevent Herpes Simplex Viral Spread

Herpes simplex virus (HSV-1) employs heparan sulfate (HS) as receptor for cell attachment and entry. During late-stage infection, the virus induces the upregulation of human heparanase (Hpse) to remove cell surface HS allowing viral spread. We hypothesized that inhibition of Hpse will prevent viral release thereby representing a new therapeutic strategy for HSV-1. A range of HS-oligosaccharides was prepared to examine the importance of chain length and 2-O-sulfation of iduronic moieties for Hpse inhibition. It was found that hexa- and octasaccharides potently inhibited the enzyme and that 2-O-sulfation of iduronic acid is tolerated. Computational studies provided a rationale for the observed structure-activity relationship. Treatment of human corneal epithelial cells (HCEs) infected with HSV-1 with the hexa- and octasaccharide blocked viral induced shedding of HS which significantly reduced spread of virions. The compounds also inhibited migration and proliferation of immortalized HCEs thereby providing additional therapeutic properties.

A Comparison of Di- and Trinuclear Platinum Complexes Interacting with Glycosaminoglycans for Targeted Chemotherapy

Heparan sulfate proteoglycans (HSPGs) and their associated proteins aid in tumor progression through modulation of biological events such as cell invasion, angiogenesis, metastasis, and immunological responses. Metalloshielding of the anionic heparan sulfate (HS) chains by cationic polynuclear platinum complexes (PPCs) prevents the HS from interacting with HS-associated proteins and thus diminishes the critical functions of HSPG. Studies herein exploring the PPC-HS interactions demonstrated that a series of PPCs varying in charge, nuclearity, distance between Pt centers, and hydrogen-bonding ability influence HS affinity. We report that the polyamine-linked complexes have high HS affinity and display excellent in vivo activity against breast cancer metastases and those arising in the bone and liver compared to carboplatin. Overall, the PPC-HS niche offers an attractive approach for targeting HSPG-expressing tumor cells.

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.

Discovery and development of small-molecule heparanase inhibitors

Heparanase-1 (HPSE) is a promising yet challenging therapeutic target. It is the only known enzyme that is responsible for cleavage of heparan sulfate (HS) side chains from heparan sulfate proteoglycans (HSPGs), and is the key enzyme involved in the remodeling and degradation of the extracellular matrix (ECM). Overexpression of HPSE is found in various types of diseases, including cancers, inflammations, diabetes, and viral infections. Inhibiting HPSE can restore ECM functions and integrity, making the development of HPSE inhibitors a highly sought-after topic. So far, all HPSE inhibitors that have entered clinical trials belong to the category of HS mimetics, and no small-molecule or drug-like HPSE inhibitors have made similar progress. None of the HS mimetics have been approved as drugs, with some clinical trials discontinued due to poor bioavailability, side effects, and unfavorable pharmacokinetics characteristics. Small-molecule HPSE inhibitors are, therefore, particularly appealing due to their drug-like characteristics. Advances in the chemical spaces and drug design technologies, including the increasing use of in vitro and in silico screening methods, have provided new opportunities in drug discovery. This article aims to review the discovery and development of small-molecule HPSE inhibitors via screening strategies to shed light on the future endeavors in the development of novel HPSE inhibitors.

The heparan sulfate mimetic Muparfostat aggravates steatohepatitis in obese mice due to its binding affinity to lipoprotein lipase

BACKGROUND AND PURPOSE

Heparanase is the only confirmed endoglycosidase that cleaves heparan sulfate (HS), a ubiquitous glycosaminoglycan with various essential roles in multiple pathological processes. Thus, the development of heparanase inhibitors has become an attractive strategy for drug discovery, especially in tumour therapy, in which HS mimetics are the most promising compounds. The various biological effects of heparanase also suggest a role for HS mimetics in many non-cancer indications, such as type 1 diabetes. However, the potential benefits of HS mimetics in obesity-related type 2 diabetes have not been elucidated.

EXPERIMENTAL APPROACH

In this study, we investigated muparfostat (PI-88), a developed HS mimetic currently enrolled in Phase III clinical trials, in obese mouse models and in vitro cultured murine hepatocytes.

KEY RESULTS

Daily administration of muparfostat for 4 weeks caused hyperlipidaemia and aggravated hepatic steatosis in obese mice models, but not in lean animals. In cultured hepatocytes, muparfostat did not alter lipid accumulation. Acute tests suggested that muparfostat binds to lipoprotein lipase in competition with HS on vascular endothelial cell surfaces, thereby reducing the degradation of circulating triglycerides by lipoprotein lipase and subsequent uptake of fatty acids into vascular endothelial cells and causing hyperlipidaemia. This hyperlipidaemia aggravates hepatic steatosis and causes liver injury in muparfostat-treated obese mice.

CONCLUSIONS AND IMPLICATIONS

The binding activity of HS mimetics to lipoprotein lipase should be investigated as an additional pharmacological effect during heparanase inhibitor drug discovery. This study also provides novel evidence for an increased risk of drug-induced liver injury in obese individuals.

Investigating the Role of Heparanase in Breast Cancer Development Utilising the MMTV-PyMT Murine Model of Mammary Carcinoma

Breast cancer is the second most common human malignancy and is a major global health burden. Heparanase (HPSE) has been widely implicated in enhancing the development and progression of solid tumours, including breast cancer. In this study, the well-established spontaneous mammary tumour-developing MMTV-PyMT murine model was utilised to examine the role of HPSE in breast cancer establishment, progression, and metastasis. The use of HPSE-deficient MMTV-PyMT (MMTV-PyMTxHPSE^-/-) mice addressed the lack of genetic ablation models to investigate the role of HPSE in mammary tumours. It was demonstrated that even though HPSE regulated mammary tumour angiogenesis, mammary tumour progression and metastasis were HPSE-independent. Furthermore, there was no evidence of compensatory action by matrix metalloproteinases (MMPs) in response to the lack of HPSE expression in the mammary tumours. These findings suggest that HPSE may not play a significant role in the mammary tumour development of MMTV-PyMT animals. Collectively, these observations may have implications in the clinical setting of breast cancer and therapy using HPSE inhibitors.

cRGD-targeted heparin nanoparticles for effective dual drug treatment of cisplatin-resistant ovarian cancer

Resistance to the chemotherapeutic agent cisplatin (DDP) is the primary reason for invalid chemotherapy of ovarian cancer. Given the complex mechanisms underlying chemo-resistance, the design of combination therapies based on blocking multiple mechanisms is a rationale to synergistically elevate therapeutic effect for effectively overcoming cancer chemo-resistance. Herein, we demonstrated a multifunctional nanoparticle (DDP-Ola@HR), which could simultaneously co-deliver DDP and Olaparib (Ola, DNA damage repair inhibitor) using targeted ligand cRGD peptide modified with heparin (HR) as nanocarrier, enabling the concurrent tackling of multiple resistance mechanisms to effectively inhibit the growth and metastasis of DDP-resistant ovarian cancer. In combination strategy, heparin could suppress the function of multidrug resistance-associated protein 2 (MRP2) and P-glycoprotein (P-gp) to promote the intracellular accumulation of DDP and Ola by specifically binding with heparanase (HPSE) to down-regulate PI3K/AKT/mTOR signaling pathway, and simultaneously served as a carrier combined with Ola to synergistically enhance the anti-proliferation ability of DDP for resistant ovarian cancer, thus achieving great therapeutic efficacy. Our DDP-Ola@HR could provide a simple and multifunctional combination strategy to trigger an anticipated cascading effect, thus effectively overcoming the chemo-resistance of ovarian cancer.

Heparin Mimetics and Their Impact on Extracellular Matrix Protein Assemblies

Heparan sulfate is a crucial extracellular matrix component that organizes structural features and functional protein processes. This occurs through the formation of protein-heparan sulfate assemblies around cell surfaces, which allow for the deliberate local and temporal control of cellular signaling. As such, heparin-mimicking drugs can directly affect these processes by competing with naturally occurring heparan sulfate and heparin chains that then disturb protein assemblies and decrease regulatory capacities. The high number of heparan-sulfate-binding proteins that are present in the extracellular matrix can cause obscure pathological effects that should be considered and examined in more detail, especially when developing novel mimetics for clinical use. The objective of this article is to investigate recent studies that present heparan-sulfate-mediated protein assemblies and the impact of heparin mimetics on the assembly and function of these protein complexes.

An ultrasensitive FRET-based fluorescent low molecular weight heparin nanoprobe for quantifying heparanase activity

Heparanase (HPA) is a multifaceted endo-β-glucuronidase, and its dysregulation facilitates cancer metastasis. Developing techniques for fast and sensitively monitoring HPA enzymatic activity is crucial for searching for molecular therapies targeting HPA. Herein, we developed a novel fluorescence resonance energy transfer (FRET)-based nanoprobe AuNCs-LMWH-AuNRs, with AuNCs@GSH-cys and AuNRs/end-NH₂/side-SiO₂ attached to the non-reducing terminus and reducing terminus of low molecular weight heparin (LMWH), respectively. AuNCs@GSH-cys exhibited an absolute quantum yield of 1.1%. The absorption spectra of AuNRs/end-NH₂/side-SiO₂ (825 nm for maximum longitudinal absorption) and the emission spectra of AuNCs@GSH-cys (824 nm for maximum emission) were precisely overlapping, further enhancing the efficiency of FRET. In the presence of HPA, the LMWH nanoprobe exhibited an ultrasensitive response with excitation/emission wavelength (lambda (ex) = 560 nm, lambda (em) = 824 nm). The probe presented a wide linear dynamic detection range (LDR) of 0.125 ng/μL - 0.01 μg/μL in vitro with a limit of detection (LODs) of 82.15 pM (0.43 pg/μL). The excellent selectivity and good fluorescence turn-on efficiency of the probe made it possible for one-step detection of cellular heparanase activity. High throughput screening of HPA inhibitors also can be accomplished using the highly efficient LMWH nanoprobe.

4-O-Substituted Glucuronic Cyclophellitols are Selective Mechanism-Based Heparanase Inhibitors

Degradation of the extracellular matrix (ECM) supports tissue integrity and homeostasis, but is also a key factor in cancer metastasis. Heparanase (HPSE) is a mammalian ECM-remodeling enzyme with β-D-endo-glucuronidase activity overexpressed in several malignancies, and is thought to facilitate tumor growth and metastasis. By this virtue, HPSE is considered an attractive target for the development of cancer therapies, yet to date no HPSE inhibitors have progressed to the clinic. Here we report on the discovery of glucurono-configured cyclitol derivatives featuring simple substituents at the 4-O-position as irreversible HPSE inhibitors. We show that these compounds, unlike glucurono-cyclophellitol, are selective for HPSE over β-D-exo-glucuronidase (GUSB), also in platelet lysate. The observed selectivity is induced by steric and electrostatic interactions of the substituents at the 4-O-position. Crystallographic analysis supports this rationale for HPSE selectivity, and computer simulations provide insights in the conformational preferences and binding poses of the inhibitors, which we believe are good starting points for the future development of HPSE-targeting antimetastatic cancer drugs.

Molecular Characteristics of Toxicity of Acrolein Produced from Spermine

Acrolein (CH₂=CH-CHO), an unsaturated aldehyde produced from spermine, is one of the major contributors to oxidative stress. Acrolein has been found to be more toxic than reactive oxygen species (H₂O₂ and •OH), and it can be easily conjugated with proteins, bringing about changes in nature of the proteins. Acrolein is detoxified by glutathione in cells and was found to be mainly produced from spermine through isolating two cell lines of acrolein-resistant Neuro2a cells. The molecular characteristics of acrolein toxicity and tissue damage elicited by acrolein were investigated. It was found that glyceraldehyde-3-phosphate dehydrogenase (GAPDH); cytoskeleton proteins such as vimentin, actin, α- and β-tubulin proteins; and apolipoprotein B-100 (ApoB100) in LDL are strongly damaged by acrolein conjugation. In contrast, activities of matrix metalloproteinase-9 (MMP-9) and proheparanase (proHPSE) are enhanced, and antibody-recognizing abilities of immunoglobulins are modified by acrolein conjugation, resulting in aggravation of diseases. The functional changes of these proteins by acrolein have been elucidated at the molecular level. The findings confirmed that acrolein is the major contributor causing tissue damage in the elderly.

Paving the road to make chimeric antigen receptor-T-cell therapy effective against solid tumors

The three major standard therapies, that is, surgery, chemotherapy, and radiation therapy have conventionally been applied to the treatments for cancers and have saved many patients. In addition, for intractable, refractory, or advanced malignancies that cannot be cured by the three standard therapies, immunotherapy is an important subject of basic and clinical researches. Immune checkpoint inhibitor therapy (ICI) has shown significant therapeutic efficacies on some types of tumors in large-scale randomized clinical trials, making a major impact on clinical oncology by scientifically proving and establishing the effectiveness of an immunotherapy. In 2018, ICI was awarded the Nobel Prize in Physiology or Medicine, and immunotherapy is now becoming the "fourth" standard therapy for cancers. Recently, adoptive cell therapies, in which genetically modified T cells with enhanced reactivity against tumors are infused into the patients, have been attracting considerable attention as a hopeful immunotherapy following ICI. Particularly, chimeric antigen receptor (CAR)-T-cell therapies demonstrate marked therapeutic efficacies against some hematologic malignancies, and have been approved in many countries. However, current CAR-T-cell therapy is considered to be little effective against solid tumors, which is one of the challenging issues to be overcome in CAR-T-cell therapy. In this review, we at first introduce CAR and CAR-T cell, and then focus on the recent progress of CAR-T-cell therapy against solid tumors as well as the novel concept on a role of CAR-T cells, aiming to further understandings of the novel cancer immunotherapies.

Small Extracellular Vesicles and Their Involvement in Cancer Resistance: An Up-to-Date Review

In recent years, tremendous progress has been made in understanding the roles of extracellular vesicles (EVs) in cancer. Thanks to advancements in molecular biology, it has been found that the fraction of EVs called exosomes or small EVs (sEVs) modulates the sensitivity of cancer cells to chemotherapeutic agents by delivering molecularly active non-coding RNAs (ncRNAs). An in-depth analysis shows that two main molecular mechanisms are involved in exosomal modified chemoresistance: (1) translational repression of anti-oncogenes by exosomal microRNAs (miRs) and (2) lack of translational repression of oncogenes by sponging of miRs through long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs). At the cellular level, these processes increase the proliferation and survival of cancer cells and improve their ability to metastasize and resist apoptosis. In addition, studies in animal models have shown enhancing tumor size under the influence of exosomal ncRNAs. Ultimately, exosomal ncRNAs are responsible for clinically significant chemotherapy failures in patients with different types of cancer. Preliminary data have also revealed that exosomal ncRNAs can overcome chemotherapeutic agent resistance, but the results are thoroughly fragmented. This review presents how exosomes modulate the response of cancer cells to chemotherapeutic agents. Understanding how exosomes interfere with chemoresistance may become a milestone in developing new therapeutic options, but more data are still required.

Mechanism-based heparanase inhibitors reduce cancer metastasis in vivo

Cancer growth is accompanied by changes to the extracellular environment of tumors, which aids the proliferation and spread of cancer cells. Cancer-associated extracellular matrix changes include excessive degradation of heparan sulfate carbohydrates, promoting metastatic spread by multiple mechanisms. Heparanase is the main human enzyme responsible for extracellular heparan sulfate breakdown and strongly drives metastasis when overexpressed. Few effective heparanase inhibitors are known, and the most effective molecules to date possess nondrug-like structures with multiple off-target effects. We have carried out structure-guided development of heparanase inhibitors, which covalently bind to the enzyme active site to cause irreversible inhibition. These inhibitors are heparanase specific and reduce metastasis in animal models with comparable efficacy to current “best-in-class” compounds.

Heparan sulfate proteoglycans (HSPGs) mediate essential interactions throughout the extracellular matrix (ECM), providing signals that regulate cellular growth and development. Altered HSPG composition during tumorigenesis strongly aids cancer progression. Heparanase (HPSE) is the principal enzyme responsible for extracellular heparan sulfate catabolism and is markedly up-regulated in aggressive cancers. HPSE overactivity degrades HSPGs within the ECM, facilitating metastatic dissemination and releasing mitogens that drive cellular proliferation. Reducing extracellular HPSE activity reduces cancer growth, but few effective inhibitors are known, and none are clinically approved. Inspired by the natural glycosidase inhibitor cyclophellitol, we developed nanomolar mechanism-based, irreversible HPSE inhibitors that are effective within physiological environments. Application of cyclophellitol-derived HPSE inhibitors reduces cancer aggression in cellulo and significantly ameliorates murine metastasis. Mechanism-based irreversible HPSE inhibition is an unexplored anticancer strategy. We demonstrate the feasibility of such compounds to control pathological HPSE-driven malignancies.

Identification of Novel Potential Heparanase Inhibitors Using Virtual Screening

Heparanase (HPSE) is a mammalian endo-β-D-glucuronidase that cleaves heparan sulphate (HS) side chains of heparin sulphate proteoglycans (HSPG), a class of molecules composed of repeating polysulfated disaccharide units of glucosamine and hexuronic acid residues. HPSE controls the availability of growth factors, chemokines, lipoproteins and other bioactive molecules by degrading HS into smaller fractions, allowing the release of saccharide fragments that activate a plethora of signaling processes. HPSE overexpression has been correlated with tumor survival and metastasis as well as several diseases associated with chronic inflammation, including the ongoing COVID-19 pandemic caused by SARS-CoV-2. Thus, the search for molecules that could potentially inhibit HPSE has become increasingly relevant in the clinic. In this study, we have integrated a strategy that combines virtual screening and molecular docking of publicly available chemical databases to identify small compounds that can be developed into novel HPSE inhibitors. Structural rationalization of the interactions previously reported compounds led us to identify promising unexplored chemotypes. Here we show that these novel potential HPSE inhibitors present optimized in silico druggability and docking properties and may serve as pharmacological tools for the treatment of chronic and infectious diseases associated with chronic inflammation.

Anticancer Effects with Molecular Docking Confirmation of Newly Synthesized Isatin Sulfonamide Molecular Hybrid Derivatives against Hepatic Cancer Cell Lines

The current study investigated the cytotoxic effect of ten sulfonamide-derived isatins, following molecular hybridization, based on the association principles, on hepatocellular carcinoma (HCC) HepG2 and Huh7 cell lines, compared for safety using human normal retina pigmented epithelial (RPE-1) cells. The ten compounds showed variable in vitro cytotoxicity on HepG2 and Huh7 cells, using the MTT assay. Four compounds (4/10) were highly cytotoxic to both HepG2 and HuH7. However, only 3 of these 4 were of the highest safety margin on RPE-1 cells in vitro and in the in vivo acute (14-day) oral toxicity study. These later, superior three compounds’ structures are 3-hydroxy-3-(2-oxo-2-(p-tolyl)ethyl)-5-(piperidin-1-ylsulfonyl)indolin-2-one (3a), N-(4-(2-(2-oxo-5-(piperidin-1-ylsulfonyl)indolin-3-ylidene)acetyl)phenyl)acetamide (4b), and N-(3-(2-(2-oxo-5-(piperidin-1-ylsulfonyl)indolin-3-ylidene)acetyl)phenyl)acetamide (4c). The half-maximal inhibitory concentration (IC50) of the tested compounds (3a, 4b, and 4c) on HepG2 cells were approximately 16.8, 44.7, and 39.7 μM, respectively. The 3a, 4b, and 4c compounds significantly decreased the angiogenic marker epithelial growth factor receptor (EGFR) level and that was further confirmed via molecular docking inside the EFGR active site (PDB: 1M17). The binding free energies ranged between −19.21 and −21.74 Kcal/mol compared to Erlotinib (−25.65 Kcal/mol). The most promising compounds, 3a, 4b, and 4c, showed variable anticancer potential on “hallmarks of cancer”, significant cytotoxicity, and apoptotic anti-angiogenic and anti-invasive effects, manifested as suppression of Bcl-2, urokinase plasminogen activation, and heparanase expression in HepG2-treated cells’ lysate, compared to non-treated HepG2 cells. In conclusion, compound “3a” is highly comparable to doxorubicin regarding cell cycle arrest at G2/M, the pre-G0 phases and early and late apoptosis induction and is comparable to Erlotinib regarding binding to EGFR active site. Therefore, the current study could suggest that compound “3a” is, hopefully, the most safe and active synthesized isatin sulfonamide derivative for HCC management.

Structural Insights into Pixatimod (PG545) Inhibition of Heparanase, a Key Enzyme in Cancer and Viral Infections

Pixatimod (PG545), a heparan sulfate (HS) mimetic and anticancer agent currently in clinical trials, is a potent inhibitor of heparanase. Heparanase is an endo‐β‐glucuronidase that degrades HS in the extracellular matrix and basement membranes and is implicated in numerous pathological processes such as cancer and viral infections, including SARS−CoV‐2. To understand how PG545 interacts with heparanase, we firstly carried out a conformational analysis through a combination of NMR experiments and molecular modelling which showed that the reducing end β‐D‐glucose residue of PG545 adopts a distorted conformation. This was followed by docking and molecular dynamics simulations to study the interactions of PG545 with heparanase, revealing that PG545 is able to block the active site by binding in different conformations, with the cholestanol side‐chain making important hydrophobic interactions. While PG545 blocks its natural substrate HS from binding to the active site, small synthetic heparanase substrates are only partially excluded, and thus pentasaccharide or larger substrates are preferred for assaying this class of inhibitor. This study provides new insights for the design of next‐generation heparanase inhibitors and substrates.

Advances in CAR-T Cell Genetic Engineering Strategies to Overcome Hurdles in Solid Tumors Treatment

During this last decade, adoptive transfer of T lymphocytes genetically modified to express chimeric antigen receptors (CARs) emerged as a valuable therapeutic strategy in hematological cancers. However, this immunotherapy has demonstrated limited efficacy in solid tumors. The main obstacle encountered by CAR-T cells in solid malignancies is the immunosuppressive tumor microenvironment (TME). The TME impedes tumor trafficking and penetration of T lymphocytes and installs an immunosuppressive milieu by producing suppressive soluble factors and by overexpressing negative immune checkpoints. In order to overcome these hurdles, new CAR-T cells engineering strategies were designed, to potentiate tumor recognition and infiltration and anti-cancer activity in the hostile TME. In this review, we provide an overview of the major mechanisms used by tumor cells to evade immune defenses and we critically expose the most optimistic engineering strategies to make CAR-T cell therapy a solid option for solid tumors.

Induction of heparanase 2 (Hpa2) expression by stress is mediated by ATF3

Activity of heparanase, endoglycosidase that cleaves heparan sulfate side chains in heparan sulfate proteoglycans, is highly implicated in tumor progression and metastasis. Heparanase inhibitors are therefore being evaluated clinically as anti-cancer therapeutics. Heparanase 2 (Hpa2) is a close homolog of heparanase that lacks HS-degrading activity and functions as an endogenous inhibitor of heparanase. As a result, Hpa2 appears to attenuate tumor growth but mechanisms that regulate Hpa2 expression and determine the ratio between heparanase and Hpa2 are largely unknown. We have recently reported that the expression of Hpa2 is induced by endoplasmic reticulum (ER) and proteotoxic stresses, but the mechanism(s) underlying Hpa2 gene regulation was obscure. Here we expand the notion that Hpa2 is regulated by conditions of stress. We report that while ER and hypoxia, each alone, resulted in a 3-7 fold increase in Hpa2 expression, combining ER stress and hypoxia resulted in a noticeable, over 40-fold increase in Hpa2 expression. A prominent induction of Hpa2 expression was also quantified in cells exposed to heat shock, proteotoxic stress, lysosomal stress, and chemotherapy (cisplatin), strongly implying that Hpa2 is regulated by conditions of stress. Furthermore, analyses of the Hpa2 gene promoter led to the identification of activating-transcription-factor 3 (ATF3) as a transcription factor that mediates Hpa2 induction by stress, thus revealing, for the first time, a molecular mechanism that underlies Hpa2 gene regulation. Induction of Hpa2 and ATF3 by conditions of stress that often accompany the rapid expansion of tumors is likely translated to improved survival of cancer patients.

The Heparanase Regulatory Network in Health and Disease

The extracellular matrix (ECM) is a structural framework that has many important physiological functions which include maintaining tissue structure and integrity, serving as a barrier to invading pathogens, and acting as a reservoir for bioactive molecules. This cellular scaffold is made up of various types of macromolecules including heparan sulfate proteoglycans (HSPGs). HSPGs comprise a protein core linked to the complex glycosaminoglycan heparan sulfate (HS), the remodeling of which is important for many physiological processes such as wound healing as well as pathological processes including cancer metastasis. Turnover of HS is tightly regulated by a single enzyme capable of cleaving HS side chains: heparanase. Heparanase upregulation has been identified in many inflammatory diseases including atherosclerosis, fibrosis, and cancer, where it has been shown to play multiple roles in processes such as epithelial-mesenchymal transition, angiogenesis, and cancer metastasis. Heparanase expression and activity are tightly regulated. Understanding the regulation of heparanase and its downstream targets is attractive for the development of treatments for these diseases. This review provides a comprehensive overview of the regulators of heparanase as well as the enzyme’s downstream gene and protein targets, and implications for the development of new therapeutic strategies.

Implications and pitfalls for cancer diagnostics exploiting extracellular vesicles

Early detection of cancer in order to facilitate timely therapeutic interventions is an unsolved problem in today's clinical diagnostics. Tumors are detected so far mostly after pathological symptoms have emerged (usually already in progressed disease states), within preventive screenings, or occasionally as incidental finding. The emergence of extracellular vesicle (EV) analytics in combination with liquid biopsy sampling opened a plethora of new possibilities for the detection of tumors (and other diseases). This review gives an overview of the diversity of currently known EV species and the relevant cargo molecules representing potential biomarkers to detect, identify and characterize tumor cells. A number of molecules reported in recent years to be valuable targets for different aspects of cancer diagnostics, are presented. Furthermore, we discuss (technical) challenges and pitfalls related to the various potential applications (screening, diagnosis, prognosis, monitoring) of liquid biopsy based EV analytics, and give an outlook to possible future directions of this emerging field in oncology.

Role of heparanase 2 (Hpa2) in gastric cancer

We report that gastric cancer patients exhibiting high levels of heparanase 2 (Hpa2) survive longer. Similarly, mice administrated with gastric carcinoma cells engineered to overexpress Hpa2 produced smaller tumors and survived longer than mice administrated with control cells. These beneficial effects were found to associate with increased phosphorylation of AMP-activated protein kinase (AMPK) that play an instrumental role in cell metabolism and 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, thus establishing a loop that feeds itself where Hpa2 enhances AMPK phosphorylation that, in turn, induces Hpa2 expression, possibly leading to attenuation of gastric tumorigenesis.

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.

From Cancer to COVID-19: A Perspective on Targeting Heparan Sulfate-Protein Interactions

Heparan sulfate (HS) is a complex, polyanionic polysaccharide ubiquitously expressed on cell surfaces and in the extracellular matrix. HS interacts with numerous proteins to mediate a vast array of biological and pathological processes. Inhibition of HS‐protein interactions is thus an attractive approach for new therapeutic development for cancer and infectious diseases, including COVID‐19; however, synthesis of well‐defined native HS oligosaccharides remains challenging. This has aroused significant interest in the development of HS mimetics which are more synthetically tractable and have fewer side effects, such as undesired anticoagulant activity. This account provides a perspective on the design and synthesis of different classes of HS mimetics with useful properties, and the development of various assays and molecular modelling tools to progress our understanding of their interactions with HS‐binding proteins.

Computational Investigation Identified Potential Chemical Scaffolds for Heparanase as Anticancer Therapeutics

Heparanase (Hpse) is an endo-β-D-glucuronidase capable of cleaving heparan sulfate side chains. Its upregulated expression is implicated in tumor growth, metastasis and angiogenesis, thus making it an attractive target in cancer therapeutics. Currently, a few small molecule inhibitors have been reported to inhibit Hpse, with promising oral administration and pharmacokinetic (PK) properties. In the present study, a ligand-based pharmacophore model was generated from a dataset of well-known active small molecule Hpse inhibitors which were observed to display favorable PK properties. The compounds from the InterBioScreen database of natural (69,034) and synthetic (195,469) molecules were first filtered for their drug-likeness and the pharmacophore model was used to screen the drug-like database. The compounds acquired from screening were subjected to molecular docking with Heparanase, where two molecules used in pharmacophore generation were used as reference. From the docking analysis, 33 compounds displayed higher docking scores than the reference and favorable interactions with the catalytic residues. Complex interactions were further evaluated by molecular dynamics simulations to assess their stability over a period of 50 ns. Furthermore, the binding free energies of the 33 compounds revealed 2 natural and 2 synthetic compounds, with better binding affinities than reference molecules, and were, therefore, deemed as hits. The hit compounds presented from this in silico investigation could act as potent Heparanase inhibitors and further serve as lead scaffolds to develop compounds targeting Heparanase upregulation in cancer.

Impact of Adjuvant Treatment on Heparanase Concentration in Invasive, Unilateral Breast Cancer Patients: Results of a Prospective Single-Centre Cohort Study

Background: In recent years, great progress has been made in the treatment of breast cancer, but it is still one of the ten leading causes of death in women. The aim of the study was to evaluate the heparanase concentration of invasive breast cancer (IBrC) patients, before and after cancer adjuvant treatment. Methods: Eighty patients with stage IA to IIB IBrC receiving adjuvant treatment were included prospectively in this study. The heparanase concentrations were determined by an enzyme-linked immunosorbent assay. A univariate analysis was used to estimate the factors influencing the low or high pre-treatment concentration of heparanase and the low or high numerical decrease in heparanase concentration after completion of adjuvant treatment. Results: Treatment reduced the concentration of heparanase by almost four times in the general IBrC cohort. Higher levels of pre- and post-treatment heparanase were noted in oestrogen receptor-negative cancers than in positive ones. A higher post-treatment concentration of heparanase was found in patients with a triple-negative tumour compared to patients with a luminal B HER2 negative type of IBrC. Overweight IBrC subjects and those with a tumour diameter of ≥2 cm demonstrated a lower chance of a lower pre-treatment heparanase concentration. Interestingly, a pre-treatment heparanase concentration is the main predictor of the changes in heparanase concentration after adjuvant treatment. Follow-up revealed significantly lower progression-free survival (PFS) rates in IBrC patients with a pre-treatment concentration of heparanase higher than 181.46 pg/mL (PFS = 80%). Conclusions: Our findings provide supporting evidence that IBrC therapy reduced the heparanase levels, regardless of treatment patterns and a pre-treatment concentration of heparanase may serve as a prognostic indicator for future outcomes.

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 Inhibitors in Cancer Progression: Recent Advances

BACKGROUND

An endo-β-glucuronidase enzyme, Heparanase (HPSE), degrades the side chains of polymeric heparan sulfate (HS), a glycosaminoglycan formed by alternate repetitive units of D-glucosamine and D-glucuronic acid/L-iduronic acid. HS is a major component of the extracellular matrix and basement membranes and has been implicated in processes of the tissue's integrity and functional state. The degradation of HS by HPSE enzyme leads to conditions like inflammation, angiogenesis, and metastasis. An elevated HPSE expression with a poor prognosis and its multiple roles in tumor growth and metastasis has attracted significant interest for its inhibition as a potential anti-neoplastic target.

METHODS

We reviewed the literature from journal publication websites and electronic databases such as Bentham, Science Direct, PubMed, Scopus, USFDA, etc., about HPSE, its structure, functions, and role in cancer.

RESULTS

The present review is focused on Heparanase inhibitors (HPIns) that have been isolated from natural resources or chemically synthesized as new therapeutics for metastatic tumors and chronic inflammatory diseases in recent years. The recent developments made in the HPSE structure and function are also discussed, which can lead to the future design of HPIns with more potency and specificity for the target.

CONCLUSION

HPIns can be a better target to be explored against various cancers.

The matrix in cancer

The extracellular matrix is a fundamental, core component of all tissues and organs, and is essential for the existence of multicellular organisms. From the earliest stages of organism development until death, it regulates and fine-tunes every cellular process in the body. In cancer, the extracellular matrix is altered at the biochemical, biomechanical, architectural and topographical levels, and recent years have seen an exponential increase in the study and recognition of the importance of the matrix in solid tumours. Coupled with the advancement of new technologies to study various elements of the matrix and cell-matrix interactions, we are also beginning to see the deployment of matrix-centric, stromal targeting cancer therapies. This Review touches on many of the facets of matrix biology in solid cancers, including breast, pancreatic and lung cancer, with the aim of highlighting some of the emerging interactions of the matrix and influences that the matrix has on tumour onset, progression and metastatic dissemination, before summarizing the ongoing work in the field aimed at developing therapies to co-target the matrix in cancer and cancer metastasis.

Heparanase 2 (Hpa2) attenuates the growth of pancreatic carcinoma

While the pro-tumorigenic properties of the ECM-degrading heparanase enzyme are well documented, the role of its close homolog, heparanase 2 (Hpa2), in cancer is largely unknown. We examined the role of Hpa2 in pancreatic cancer, a malignancy characterized by a dense fibrotic ECM associated with poor response to treatment and bad prognosis. We show that pancreatic ductal adenocarcinoma (PDAC) patients that exhibit high levels of Hpa2 survive longer than patients with low levels of Hpa2. Strikingly, overexpression of Hpa2 in pancreatic carcinoma cells resulted in a most prominent decrease in the growth of tumors implanted orthotopically and intraperitoneally, whereas Hpa2 silencing resulted in bigger tumors. We further found that Hpa2 enhances endoplasmic reticulum (ER) stress response and renders cells more sensitive to external stress, associating with increased apoptosis. Interestingly, we observed that ER stress induces the expression of Hpa2, thus establishing a feedback loop by which Hpa2 enhances ER stress that, in turn, induces Hpa2 expression. This leads to increased apoptosis and attenuated tumor growth. Altogether, Hpa2 emerges as a powerful tumor suppressor in pancreatic cancer.

Dissociation of DNA damage sensing by endoglycosidase HPSE

Balance between cell proliferation and elimination is critical in handling threats both exogenous and of internal dysfunction. Recent work has implicated a conserved but poorly understood endoglycosidase heparanase (HPSE) in the restriction of innate defense responses, yet biochemical mediators of these key functions remained unclear. Here, an unbiased immunopurification proteomics strategy is employed to identify and rank uncharacterized interactions between HPSE and mediators of canonical signaling pathways linking cell cycle and stress responses. We demonstrate with models of genotoxic stress including herpes simplex virus infection and chemotherapeutic treatment that HPSE dampens innate responses to double-stranded DNA breakage by interfering with signal transduction between initial sensors and downstream mediators. Given the long-standing recognition of HPSE in driving late-stage inflammatory disease exemplified by tissue destruction and cancer metastasis, modulation of this protein with control over the DNA damage response imparts a unique strategy in the development of unconventional multivalent therapy.

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HPSE binds key proteins at interface of DNA damage signaling and IFN responses

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Nuclear translocation of DNA damage transducer ATM is enhanced in absence of HPSE

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Cells lacking HPSE display enhanced sensitivity to DNA damage-induced death

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HPSE interfaces with regulators of DNA damage response to influence cell fate

Elucidating the Consequences of Heparan Sulfate Binding by Heparanase 2

Unlike the intense research effort devoted to exploring the significance of heparanase in human diseases, very little attention was given to its close homolog, heparanase 2 (Hpa2). The emerging role of Hpa2 in a rare autosomal recessive congenital disease called urofacial syndrome (UFS), clearly indicates that Hpa2 is not a pseudogene but rather a gene coding for an important protein. Hpa2 lacks the heparan sulfate (HS)-degrading activity typical of heparanase, yet exhibits high affinity to HS, affinity that is 10-fold higher than that of heparanase. The consequences of this high-affinity interaction of Hpa2 with plasma membrane HSPG has not been explored yet. Here, we used highly purified Hpa2 protein to examine this aspect. We provide evidence that cells adhere to and spread on dishes coated with Hpa2. We also show that cell migration is attenuated markedly by exogenous addition of Hpa2 to primary and transformed cells, a function that agrees with the anti-cancer properties of Hpa2. Interestingly, we found that exogenous addition of Hpa2 also disrupts the morphology of cell colonies, resulting in cell scattering. This implies that under certain conditions and experimental settings, Hpa2 may exhibit pro-tumorigenic properties. We further developed a panel of anti-Hpa2 monoclonal antibodies (mAb) and show that these properties of Hpa2 are prevented by some of the newly-developed mAb, thus providing new molecular tools to better appreciate the significance of Hpa2 in health and disease.

Heparan Sulfate Glycosaminoglycans: (Un)Expected Allies in Cancer Clinical Management

In an era when cancer glycobiology research is exponentially growing, we are witnessing a progressive translation of the major scientific findings to the clinical practice with the overarching aim of improving cancer patients' management. Many mechanistic cell biology studies have demonstrated that heparan sulfate (HS) glycosaminoglycans are key molecules responsible for several molecular and biochemical processes, impacting extracellular matrix properties and cellular functions. HS can interact with a myriad of different ligands, and therefore, hold a pleiotropic role in regulating the activity of important cellular receptors and downstream signalling pathways. The aberrant expression of HS glycan chains in tumours determines main malignant features, such as cancer cell proliferation, angiogenesis, invasion and metastasis. In this review, we devote particular attention to HS biological activities, its expression profile and modulation in cancer. Moreover, we highlight HS clinical potential to improve both diagnosis and prognosis of cancer, either as HS-based biomarkers or as therapeutic targets.

Ischemic stroke disrupts the endothelial glycocalyx through activation of proHPSE via acrolein exposure

Infiltration of peripheral immune cells after blood-brain barrier dysfunction causes severe inflammation after a stroke. Although the endothelial glycocalyx, a network of membrane-bound glycoproteins and proteoglycans that covers the lumen of endothelial cells, functions as a barrier to circulating cells, the relationship between stroke severity and glycocalyx dysfunction remains unclear. In this study, glycosaminoglycans, a component of the endothelial glycocalyx, were studied in the context of ischemic stroke using a photochemically induced thrombosis mouse model. Decreased levels of heparan sulfate and chondroitin sulfate and increased activity of hyaluronidase 1 and heparanase (HPSE) were observed in ischemic brain tissues. HPSE expression in cerebral vessels increased after stroke onset and infarct volume greatly decreased after co-administration of N-acetylcysteine + glycosaminoglycan oligosaccharides as compared with N-acetylcysteine administration alone. These results suggest that the endothelial glycocalyx was injured after the onset of stroke. Interestingly, scission activity of proHPSE produced by immortalized endothelial cells and HEK293 cells transfected with hHPSE1 cDNA were activated by acrolein (ACR) exposure. We identified the ACR-modified amino acid residues of proHPSE using nano LC-MS/MS, suggesting that ACR modification of Lys139 (6-kDa linker), Lys107, and Lys161, located in the immediate vicinity of the 6-kDa linker, at least in part is attributed to the activation of proHPSE. Because proHPSE, but not HPSE, localizes outside cells by binding with heparan sulfate proteoglycans, ACR-modified proHPSE represents a promising target to protect the endothelial glycocalyx.

Heparanase-enhanced Shedding of Syndecan-1 and Its Role in Driving Disease Pathogenesis and Progression

Both heparanase and syndecan-1 are known to be present and active in disease pathobiology. An important feature of syndecan-1 related to its role in pathologies is that it can be shed from the surface of cells as an intact ectodomain composed of the extracellular core protein and attached heparan sulfate and chondroitin sulfate chains. Shed syndecan-1 remains functional and impacts cell behavior both locally and distally from its cell of origin. Shedding of syndecan-1 is initiated by a variety of stimuli and accomplished predominantly by the action of matrix metalloproteinases. The accessibility of these proteases to the core protein of syndecan-1 is enhanced, and shedding facilitated, when the heparan sulfate chains of syndecan-1 have been shortened by the enzymatic activity of heparanase. Interestingly, heparanase also enhances shedding by upregulating the expression of matrix metalloproteinases. Recent studies have revealed that heparanase-induced syndecan-1 shedding contributes to the pathogenesis and progression of cancer and viral infection, as well as other septic and non-septic inflammatory states. This review discusses the heparanase/shed syndecan-1 axis in disease pathogenesis and progression, the potential of targeting this axis therapeutically, and the possibility that this axis is widespread and of influence in many diseases.

[Heparanase promotes trans-endothelial migration of hepatocarcinoma cells by inducing apoptosis of microvascular endothelial cells]

OBJECTIVE

To explore the effect of heparanase (HPSE) on apoptosis of microvascular endothelial cells (MVECs) and trans-endothelial migration of hepatocellular carcinoma (HCC) cells.

METHODS

A HCC cell line with high HPSE expression was selected by real-time quantitative PCR (qRT-PCR) and Western blotting and transefected with a lentiviral vector containing an interfering RNA sequence of HPSE. Transwell migration assay was performed to detect the trans-endothelial migration (TEM) rate of the transfected HCC cells across human umbilical vein endothelial cells (HUVECs). In a Transwell indirect co-culture system, the effect of HPSE silencing in the HCC cells was determined on apoptosis of HUVECs in vitro. A nude mouse model of HCC was used to verify the effect of HPSE on apoptosis of MVECs and liver metastasis of the tumor.

RESULTS

HCCLM3 cell line highly expressing HPSE was selected for the experiment. Transfection of the HCC cells with the lentiviral vector for HPSE interference the HCC cells resulted in significantly lowered TEM rate as compared with the cells transfected with the control vector (P < 0.01). In the indirect co-culture system, the survival rate of HUVECs co-cultured with HCCLM3 cells with HPSE interference was significantly higher and their apoptotic index was significantly lower than those in the control group (P < 0.05). Ultrastructural observation showed no obvious apoptosis of HUVECs co-cultured with HCCLM3 cells with HPSE interference but revealed obvious apoptotic changes in the control group. In the animal experiment, the tumor formation rate in the liver was 100% (6/6) in the control group, significantly higher than that in RNAi group (33.3%, 2/6) (P < 0.05). Under optical microscope, necrosis and apoptosis of the MVECs was detected in the liver of the control mice, while the endothelial cells remained almost intact in RNAi group.

CONCLUSIONS

HPSE promotes the metastasis of HCC cells by inducing apoptosis of MVECs.

Proteoglycans in the Pathogenesis of Hormone-Dependent Cancers: Mediators and Effectors

Hormone-dependent cancers exhibit high morbidity and mortality. In spite of advances in therapy, the treatment of hormone-dependent cancers remains an unmet health need. The tumor microenvironment (TME) exhibits unique characteristics that differ among various tumor types. It is composed of cancerous, non-cancerous, stromal, and immune cells that are surrounded and supported by components of the extracellular matrix (ECM). Therefore, the interactions among cancer cells, stromal cells, and components of the ECM determine cancer progression and response to therapy. Proteoglycans (PGs), hybrid molecules consisting of a protein core to which sulfated glycosaminoglycan chains are bound, are significant components of the ECM that are implicated in all phases of tumorigenesis. These molecules, secreted by both the stroma and cancer cells, are crucial signaling mediators that modulate the vital cellular pathways implicated in gene expression, phenotypic versatility, and response to therapy in specific tumor types. A plethora of deregulated signaling pathways contributes to the growth, dissemination, and angiogenesis of hormone-dependent cancers. Specific inputs from the endocrine and immune systems are some of the characteristics of hormone-dependent cancer pathogenesis. Importantly, the mechanisms involved in various aspects of cancer progression are executed in the ECM niche of the TME, and the PG components crucially mediate these processes. Here, we comprehensively discuss the mechanisms through which PGs affect the multifaceted aspects of hormone-dependent cancer development and progression, including cancer metastasis, angiogenesis, immunobiology, autophagy, and response to therapy.

Structural insights into heparanase activity using a fluorogenic heparan sulfate disaccharide

Crystal structures with human heparanase provide the first ever observation of a substrate in an activated ¹S₃ conformation.