FGF2 binding, signaling, and angiogenesis are modulated by heparanase in metastatic melanoma cells

Melanoma-derived extracellular vesicles transfer proangiogenic factors

Angiogenesis, the expansion of pre-existing vascular networks, is crucial for normal organ growth and tissue repair, but is also involved in various pathologies, including inflammation, ischemia, diabetes, and cancer. In solid tumors, angiogenesis supports growth, nutrient delivery, waste removal, and metastasis. Tumors can induce angiogenesis through proangiogenic factors including VEGF, FGF-2, PDGF, angiopoietins, HGF, TNF, IL-6, SCF, tryptase, and chymase. This balance is disrupted in tumors, and extracellular vesicles (EVs) contribute to this by transferring proangiogenic factors and increasing their expression in endothelial cells (ECs). Malignant melanoma, a particular type of skin cancer, accounts for only 1% of skin cancer cases but more than 75% of deaths. Its incidence has risen significantly, with a 40% increase between 2012 and 2022, especially in fair-skinned populations. Advanced metastatic stages have a high mortality due to delayed diagnosis. This review examines the molecular basis of angiogenesis in melanoma, focusing on melanoma-derived EVs and their possible use in new antiangiogenic therapies.

LGALS3BP is a novel and potential biomarker in clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is the most common solid renal tumor. Therefore, it is necessary to explore the related tumor markers. LGALS3BP (galectin 3 binding protein) is a multifunctional glycoprotein implicated in immunity and cancer. Some studies have shown that LGALS3BP promotes the occurrence and development of tumors. However, their exact role in renal tumorigenesis remains unclear. Our study used a webserver to explore the mRNA expression and clinical features of LGALS3BP in ccRCC. Survival analysis showed that patients with high LGALS3BP expression had significantly worse OS and DFS than those with low LGALS3BP expression. LGALS3BP expression is significantly related to B cells, CD4+ T cells, macrophages, neutrophils, and dendritic cells. Furthermore, we determined that LGALS3BP is significantly associated with angiogenesis, stemness and proliferation in renal cancer. Three phenotypes may be associated with a poor prognosis. Genes related to proliferation, angiogenesis and stemness were derived from a Venn diagram of FGF2. FGF2 is negatively correlated with proliferation and positively correlated with angiogenesis. Finally, we screened for drugs that may have potential therapeutic value for ccRCC. The PCR results showed that the expression of LGALS3BP in the normal cell line was lower than that in the tumor cell lines. After LGALS3BP knockdown, the proliferation of 769-P and 786-O cells decreased. The present findings show that LGALS3BP is critical for ccRCC cell proliferation and may be a potential target and biomarker for ccRCC.

Heparanase-1: From Cancer Biology to a Future Antiviral Target

Heparan sulfate proteoglycans (HSPGs) are a major constituent of the extracellular matrix (ECM) and are found to be implicated in viral infections, where they play a role in both cell entry and release for many viruses. The enzyme heparanase-1 is the only known endo-beta-D-glucuronidase capable of degrading heparan sulphate (HS) chains of HSPGs and is thus important for regulating ECM homeostasis. Heparanase-1 expression is tightly regulated as the uncontrolled cleavage of HS may result in abnormal cell activation and significant tissue damage. The overexpression of heparanase-1 correlates with pathological scenarios and is observed in different human malignancies, such as lymphoma, breast, colon, lung, and hepatocellular carcinomas. Interestingly, heparanase-1 has also been documented to be involved in numerous viral infections, e.g., HSV-1, HPV, DENV. Moreover, very recent reports have demonstrated a role of heparanase-1 in HCV and SARS-CoV-2 infections. Due to the undenied pro-carcinogenic role of heparanase-1, multiple inhibitors have been developed, some reaching phase II and III in clinical studies. However, the use of heparanase inhibitors as antivirals has not yet been proposed. If it can be assumed that heparanase-1 is implicated in numerous viral life cycles, its inhibition by specific heparanase-acting compounds should result in a blockage of viral infection. This review addresses the perspectives of using heparanase inhibitors, not only for cancer treatment, but also as antivirals. Eventually, the development of a novel class antivirals targeting a cellular protein could help to alleviate the resistance problems seen with some current antiretroviral therapies.

Detection of melanogenesis- and anti-apoptosis-associated melanoma factors: Array CGH and PPI mapping integrating study

BACKGROUND

We investigated melanogenesis- and anti-apoptosis-related melanoma factors in melanoma cells (TXM1, TXM18, A375P, and A375SM).

OBJECTIVE

To find melanoma associated hub factor, high-throughput screening-based techniques integrating with bioinformatics were investigated.

METHODS

Array CGH analysis was conducted with a commercial system. Total genomic DNAs prepared individually from each cell line with control DNA were properly labeled with Cy3-dCTP and Cy5-dCTP and hybridizations and subsequently performed data treatment by the log2 green (G; test) to red (R; reference) fluorescence ratios (G/R). Gain or loss of copy number was judged by spots with log2-transformed ratios. PPI mapping analysis of detected candidate genes based on the array CGH results was conducted using the human interactome in the STRING database. Energy minimization and a short molecular dynamics (MD) simulation using the implicit solvation model in CHARMM were performed to analyze the interacting residues between YWHAZ and YWHAB.

RESULTS

Three genes (BMP-4, BFGF, LEF-1) known to be involved in melanogenesis were found to lose chromosomal copy numbers, and Chr. 6q23.3 was lost in all tested cell lines. Ten hub genes (CTNNB1, PEX13, PEX14, PEX5, IFNG, EXOSC3, EXOSC1, EXOSC8, UBC, and PEX10) were predicted to be functional interaction factors in the network of the 6q23.3 locus. The apoptosis-associated genes E2F1, p50, BCL2L1, and BIRC7 gained, and FGF2 lost chromosomal copy numbers in the tested melanoma cell lines. YWHAB, which gained chromosomal copy numbers, was predicted to be the most important hub protein in melanoma cells. Molecular dynamics simulations for binding YWHAB and YWHAZ were conducted, and the complex was predicted to be energetically and structurally stable through its 3 hydrogen-bond patterns. The number of interacting residues is 27.

CONCLUSION

Our study compares genome-wide screening interactomics predictions for melanoma factors and offers new information for understanding melanogenesis- and anti-apoptosis-associated mechanisms in melanoma. Especially, YWHAB was newly detected as a core factor in melanoma cells.

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.

Harnessing Extracellular Matrix Biology for Tumor Drug Delivery

The extracellular matrix (ECM) plays an active role in cell life through a tightly controlled reciprocal relationship maintained by several fibrous proteins, enzymes, receptors, and other components. It is also highly involved in cancer progression. Because of its role in cancer etiology, the ECM holds opportunities for cancer therapy on several fronts. There are targets in the tumor-associated ECM at the level of signaling molecules, enzyme expression, protein structure, receptor interactions, and others. In particular, the ECM is implicated in invasiveness of tumors through its signaling interactions with cells. By capitalizing on the biology of the tumor microenvironment and the opportunities it presents for intervention, the ECM has been investigated as a therapeutic target, to facilitate drug delivery, and as a prognostic or diagnostic marker for tumor progression and therapeutic intervention. This review summarizes the tumor ECM biology as it relates to drug delivery with emphasis on design parameters targeting the ECM.

Perlecan in the Natural and Cell Therapy Repair of Human Adult Articular Cartilage: Can Modifications in This Proteoglycan Be a Novel Therapeutic Approach?

Articular cartilage is considered to have limited regenerative capacity, which has led to the search for therapies to limit or halt the progression of its destruction. Perlecan, a multifunctional heparan sulphate (HS) proteoglycan, promotes embryonic cartilage development and stabilises the mature tissue. We investigated the immunolocalisation of perlecan and collagen between donor-matched biopsies of human articular cartilage defects (n = 10 × 2) that were repaired either naturally or using autologous cell therapy, and with age-matched normal cartilage. We explored how the removal of HS from perlecan affects human chondrocytes in vitro. Immunohistochemistry showed both a pericellular and diffuse matrix staining pattern for perlecan in both natural and cell therapy repaired cartilage, which related to whether the morphology of the newly formed tissue was hyaline cartilage or fibrocartilage. Immunostaining for perlecan was significantly greater in both these repair tissues compared to normal age-matched controls. The immunolocalisation of collagens type III and VI was also dependent on tissue morphology. Heparanase treatment of chondrocytes in vitro resulted in significantly increased proliferation, while the expression of key chondrogenic surface and genetic markers was unaffected. Perlecan was more prominent in chondrocyte clusters than in individual cells after heparanase treatment. Heparanase treatment could be a means of increasing chondrocyte responsiveness to cartilage injury and perhaps to improve repair of defects.

Involvement of Syndecan-1 and Heparanase in Cancer and Inflammation

The cell surface heparan sulfate proteoglycan Syndecan-1 acts as an important co-receptor for receptor tyrosine kinases and chemokine receptors, and as an adhesion receptor for structural glycoproteins of the extracellular matrix. It serves as a substrate for heparanase, an endo-β-glucuronidase that degrades specific domains of heparan sulfate carbohydrate chains and thereby alters the functional status of the proteoglycan and of Syndecan-1-bound ligands. Syndecan-1 and heparanase show multiple levels of functional interactions, resulting in mutual regulation of their expression, processing, and activity. These interactions are of particular relevance in the context of inflammation and malignant disease. Studies in animal models have revealed a mechanistic role of Syndecan-1 and heparanase in the regulation of contact allergies, kidney inflammation, multiple sclerosis, inflammatory bowel disease, and inflammation-associated tumorigenesis. Moreover, functional interactions between Syndecan-1 and heparanase modulate virtually all steps of tumor progression as defined in the Hallmarks of Cancer. Due to their prognostic value in cancer, and their mechanistic involvement in tumor progression, Syndecan-1 and heparanase have emerged as important drug targets. Data in preclinical models and preclinical phase I/II studies have already yielded promising results that provide a translational perspective.

Modulating Heparanase Activity: Tuning Sulfation Pattern and Glycosidic Linkage of Oligosaccharides

Heparanase cleaves polymeric heparan sulfate (HS) molecules into smaller oligosaccharides, allowing for release of angiogenic growth factors promoting tumor development and autoreactive immune cells to reach the insulin-producing β cells. Interaction of heparanase with HS chains is regulated by specific substrate sulfation sequences. We have synthesized 11 trisaccharides that are highly tunable in structure and sulfation pattern, allowing us to determine how heparanase recognizes HS substrate and selects a favorable cleavage site. Our study shows that (1) N-SO₃^- at +1 subsite and 6-O-SO₃^- at -2 subsite of trisaccharides are critical for heparanase recognition, (2) addition of 2-O-SO₃^- at the -1 subsite and of 3-O-SO₃^- to GlcN unit is not advantageous, and (3) the anomeric configuration (α or β) at the reducing end is crucial in controlling heparanase activity. Our study also illustrates that the α-trisaccharide having N- and 6-O-SO₃^- at -2 and +1 subsites inhibited heparanase and was resistant toward hydrolysis.

Distribution of heparan sulfate correlated with the expression of heparanase-1 and matrix metalloproteinase-9 in an ovariectomized rats skin

There are few studies on heparan sulfate (HS) in the skin, during aging, when estrogen is suppressed. The enzyme heparanase-1 (HPSE-1), has its 17β-estrogen-regulated expression in pathological conditions such as cancer and chronic inflammatory diseases. HPSE-1 is correlated with the matrix metalloproteinase-9 (MMP-9), an endopeptidase that also undergoes estrogen action. We investigated the distribution of HS, expression HPSE-1 and MMP-9 in the skin of adult rats at different ages and in the age-matched ovariectomized rats to evaluate the influence of low estrogen on the distribution of HS. Thirty female Wistar rats were used. Rats underwent to a sham surgery (ctr, n = 15) or to a bilateral ovariectomy (ovx, n = 15) and were euthanized after 45, 75, and 90 days after ovariectomy. Morphological, morphometric, biochemical, and reverse transcriptase polymerase chain reaction (RT-PCR) methodologies were used. A significant decrease (P < 0.001) in total skin thickness was observed in the ctr and ovx animals, being higher in the older animals. The thickness of the epidermis and dermis decreased; however, the proportion in the total skin remained similar comparing ctr and ovx. An increase of HS with increasing age and ovariectomy was observed. The expression of the HPSE-1 and MMP-9 enzymes decreased, being higher in old animals. A correlation between the increase of HS and the decrease of the HPSE-1 was demonstrated in both groups. Overall, these data suggested that estrogen acts in the regulation of the expression of the HPSE-1, not only in pathological states, as already established, but also in aging.

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

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

End-functionalised glycopolymers as glycosaminoglycan mimetics inhibit HeLa cell proliferation

A novel glycopeptide mimetic, prepared by end-functionalised conjugation of iRGD peptide on a glycopolymer, could effectively enter HeLa cells and inhibit signalling pathways involved in tumour cell proliferation.

Heparanase Involvement in Exosome Formation

Exosomes are secreted vesicles involved in signaling processes. The biogenesis of a class of these extracellular vesicles depends on syntenin, and on the interaction of this cytosolic protein with syndecans. Heparanase, largely an endosomal enzyme, acts as a regulator of the syndecan-syntenin-exosome biogenesis pathway. The upregulation of syntenin and heparanase in cancers may support the suspected roles of exosomes in tumor biology.

Transcription Factor Prospero Homeobox 1 (PROX1) as a Potential Angiogenic Regulator of Follicular Thyroid Cancer Dissemination

It is well known that Prospero homeobox 1 (PROX1) is a crucial regulator of lymphangiogenesis, that reprograms blood endothelial cells to lymphatic phenotype. However, the role of PROX1 in tumor progression, especially in angiogenesis remains controversial. Herein, we studied the role of PROX1 in angiogenesis in cell lines derived from follicular thyroid cancer (FTC: FTC-133) and squamous cell carcinoma of the thyroid gland (SCT: CGTH-W-1) upon PROX1 knockdown. The genes involved in angiogenesis were selected by RNA-seq, and the impact of PROX1 on vascularization potential was investigated using human umbilical vein endothelial cells (HUVECs) cultured in conditioned medium collected from FTC- or SCT-derived cancer cell lines after PROX1 silencing. The angiogenic phenotype was examined in connection with the analysis of focal adhesion and correlated with fibroblast growth factor 2 (FGF2) levels. Additionally, the expression of selected genes involved in angiogenesis was detected in human FTC tissues. As a result, we demonstrated that PROX1 knockdown resulted in upregulation of factors associated with vascularization, such as metalloproteinases (MMP1 and 3), FGF2, vascular endothelial growth factors C (VEGFC), BAI1 associated protein 2 (BAIAP2), nudix hydrolase 6 (NUDT6), angiopoietin 1 (ANGPT1), and vascular endothelial growth factor receptor 2 (KDR). The observed molecular changes resulted in the enhanced formation of capillary-like structures by HUVECs and upregulated focal adhesion in FTC-133 and CGTH-W-1 cells. The signature of selected angiogenic genes' expression in a series of FTC specimens varied depending on the case. Interestingly, PROX1 and FGF2 showed opposing expression levels in FTC tissues and seven thyroid tumor-derived cell lines. In summary, our data revealed that PROX1 is involved in the spreading of thyroid cancer cells by regulation of angiogenesis.

Transcriptomic analysis reveals cell apoptotic signature modified by heparanase in melanoma cells

Heparanase has been implicated in many pathological conditions, especially inflammation and cancer, attributed to its degradation of heparan sulfate, a crucial component maintaining the integrity of the extracellular matrix. By silencing the heparanase gene (HPSE) in MDA-MB-435s melanoma cells, we investigated the impact of this protein on gene transcription. Transcriptome sequencing yielded a list of 279 differentially expressed genes, of which 140 were up-regulated and 239 down-regulated. The 140 up-regulated genes were classified into a substantial set of gene ontology defined functions, for example, positive regulation of cell death, apoptotic process, response to cytokine, while 239 down-regulated genes classify only into the two categories: nucleosome and nucleosome assembly. Our focus was drawn to an array of 28 pro-apoptotic genes regulated by heparanase: real-time PCR experiments further validated up-regulation of EGR1, TXNIP, AXL, CYR61, LIMS2 and TNFRSF12A by at least 1.5-fold, among which EGR1, CYR61, and TNFRSF12A were confirmed on protein level. We demonstrated significantly increased apoptotic cells by TUNEL staining upon HPSE silencing, mediated by activation of caspase 3/PARP1 pathway. The pro-apoptotic gene expression and observation of apoptosis were extended to another melanoma cell line, MV3 cells, thus consolidating the anti-apoptosis effect of heparanase in melanoma cells.

The amyloid precursor protein (APP) processing as a biological link between Alzheimer's disease and cancer

Aging is a risk factor for several illnesses, such as Alzheimer's Disease and various cancers. However, an inverse correlation between malignancies and Alzheimer's Disease has been suggested. This review addressed the potential role of non-amyloidogenic and amyloidogenic pathways of amyloid precursor protein processing as a relevant biochemical mechanism to clarify this association. Amyloidogenic and non-amyloidogenic pathways have been related to Alzheimer's Disease and certain malignancies, respectively. Several known molecules involved in APP processing, including its regulation and final products, were summarized. Among them some candidate mechanisms emerged, such as extracellular-regulated kinase (Erk) and protein kinase C (PKC). Therefore, the imbalance of APP processing may be involved with the negative correlation between cancer and Alzheimer Disease.

Design, synthesis, and evaluation of heparan sulfate mimicking glycopolymers for inhibiting heparanase activity

Heparanase is an enzyme which cleaves heparan sulfate (HS) polysaccharides of the extracellular matrix. It is a regulator of tumor behavior, plays a key role in kidney related diseases and autoimmune diabetes. We report herein the use of computational studies to extract the natural HS-heparanase interactions as a template for the design of HS mimicking glycopolymers. Upon evaluation, a glycopolymer with 12 repeating units was determined to be the most potent inhibitor and to have tight-binding characteristics. This glycopolymer also lacks anticoagulant activity.

The close relationship between heparanase and epithelial mesenchymal transition in gastric signet-ring cell adenocarcinoma

Heparanase (HPSE), a heparan sulfate-specific endo-β-D-glucuronidase, plays an important role in tumor cell metastasis through the degradation of extracellular matrix heparan sulfate proteoglycans. Suramin, a polysulfonated naphthylurea, is an inhibitor of HPSE with suramin analogues. Our objective was to analyze the HPSE involvement in gastric signet ring cell adenocarcinoma (SRCA) invasion. High expression of HPSE mRNA and protein was found in the tumor and in ascites of SRCA as well as in KATO-III cell line. Beside of collagen-I, growth factors (TGF-β1 and VEGF-A, except FGF-2) and epithelial mesenchymal transition (EMT) markers (Snail, Slug, Vimentin, α-SMA and Fibronectin, except E-cadherin) were found higher in main nodules of SRCA as compared to peritumoral sites. Among MDR proteins, MDR-1 and LRP (lung resistance protein) were highly expressed in tumor cells. The formation of 3D cell spheroids was found to be correlated with their origin (adherent or non-adherent KATO-III). After treatment of KATO-III cells with a HPSE inhibitor (suramin), cell proliferation and EMT-related markers, besides collagen-1 expression, were down regulated. In conclusion, in SRCA, HPSE via an autocrine secretion is involved in acquisition of mesenchymal phenotype and tumor cell malignancy. Therefore, HPSE could be an interesting pharmacological target for the treatment of SRCA.

CTC clusters induced by heparanase enhance breast cancer metastasis

Aggregated metastatic cancer cells, referred to as circulating tumor cell (CTC) clusters, are present in the blood of cancer patients and contribute to cancer metastasis. However, the origin of CTC clusters, especially intravascular aggregates, remains unknown. Here, we employ suspension culture methods to mimic CTC cluster formation in the circulation of breast cancer patients. CTC clusters generated using these methods exhibited an increased metastatic potential that was defined by the overexpression of heparanase (HPSE). Heparanase induced FAK- and ICAM-1-dependent cell adhesion, which promoted intravascular cell aggregation. Moreover, knockdown of heparanase or inhibition of its activity with JG6, a heparanase inhibitor, was sufficient to block the formation of cell clusters and suppress breast cancer metastasis. Our data reveal that heparanase-mediated cell adhesion is critical for metastasis mediated by intravascular CTC clusters. We also suggest that targeting the function of heparanase in cancer cell dissemination might limit metastatic progression.

Enhancing the Therapeutic Potential of Olfactory Ensheathing Cells in Spinal Cord Repair Using Neurotrophins

Autologous olfactory ensheathing cell (OEC) transplantation is a promising therapy for spinal cord injury; however, the efficacy varies between trials in both animals and humans. The main reason for this variability is that the purity and phenotype of the transplanted cells differs between studies. OECs are susceptible to modulation with neurotrophic factors, and thus, neurotrophins can be used to manipulate the transplanted cells into an optimal, consistent phenotype. OEC transplantation can be divided into 3 phases: (1) cell preparation, (2) cell administration, and (3) continuous support to the transplanted cells in situ. The ideal behaviour of OECs differs between these 3 phases; in the cell preparation phase, rapid cell expansion is desirable to decrease the time between damage and transplantation. In the cell administration phase, OEC survival and integration at the injury site, in particular migration into the glial scar, are the most critical factors, along with OEC-mediated phagocytosis of cellular debris. Finally, continuous support needs to be provided to the transplantation site to promote survival of both transplanted cells and endogenous cells within injury site and to promote long-term integration of the transplanted cells and angiogenesis. In this review, we define the 3 phases of OEC transplantation into the injured spinal cord and the optimal cell behaviors required for each phase. Optimising functional outcomes of OEC transplantation can be achieved by modulation of cell behaviours with neurotrophins. We identify the key growth factors that exhibit the strongest potential for optimizing the OEC phenotype required for each phase.

Activation of the A2B adenosine receptor in B16 melanomas induces CXCL12 expression in FAP-positive tumor stromal cells, enhancing tumor progression

The A2B receptor (A2BR) can mediate adenosine-induced tumor proliferation, immunosuppression and angiogenesis. Targeting the A2BR has proved to be therapeutically effective in some murine tumor models, but the mechanisms of these effects are still incompletely understood. Here, we report that pharmacologic inhibition of A2BR with PSB1115, which inhibits tumor growth, decreased the number of fibroblast activation protein (FAP)-expressing cells in tumors in a mouse model of melanoma. This effect was associated with reduced expression of fibroblast growth factor (FGF)-2. Treatment of melanoma-associated fibroblasts with the A2BR agonist Bay60-6583 enhanced CXCL12 and FGF2 expression. This effect was abrogated by PSB1115. The A2AR agonist CGS21680 did not induce CXCL12 or FGF2 expression in tumor associated fibroblasts. Similar results were obtained under hypoxic conditions in skin-derived fibroblasts, which responded to Bay60-6583 in an A2BR-dependent manner, by stimulating pERK1/2. FGF2 produced by Bay60-6583-treated fibroblasts directly enhanced the proliferation of melanoma cells. This effect could be reversed by PSB1115 or an anti-FGF2 antibody. Interestingly, melanoma growth in mice receiving Bay60-6583 was attenuated by inhibition of the CXCL12/CXCR4 pathway with AMD3100. CXCL12 and its receptor CXCR4 are involved in angiogenesis and immune-suppression. Treatment of mice with AMD3100 reduced the number of CD31+ cells induced by Bay60-6583. Conversely, CXCR4 blockade did not affect the accumulation of tumor-infiltrating MDSCs or Tregs. Together, our data reveal an important role for A2BR in stimulating FGF2 and CXCL12 expression in melanoma-associated fibroblasts. These factors contribute to create a tumor-promoting microenvironment. Our findings support the therapeutic potential of PSB1115 for melanoma.

Inhibition of Heparanase in Pediatric Brain Tumor Cells Attenuates their Proliferation, Invasive Capacity, and In Vivo Tumor Growth

Curative therapy for medulloblastoma and other pediatric embryonal brain tumors has improved, but the outcome still remains poor and current treatment causes long-term complications. Malignant brain tumors infiltrate the healthy brain tissue and, thus despite resection, cells that have already migrated cause rapid tumor regrowth. Heparan sulfate proteoglycans (HSPG), major components of the extracellular matrix (ECM), modulate the activities of a variety of proteins. The major enzyme that degrades HS, heparanase (HPSE), is an important regulator of the ECM. Here, we report that the levels of HPSE in pediatric brain tumors are higher than in healthy brain tissue and that treatment of pediatric brain tumor cells with HPSE stimulated their growth. In addition, the latent, 65 kDa form of HPSE (that requires intracellular enzymatic processing for activation) enhanced cell viability and rapidly activated the ERK and AKT signaling pathways, before enzymatically active HPSE was detected. The HPSE inhibitor PG545 efficiently killed pediatric brain tumor cells, but not normal human astrocytes, and this compound also reduced tumor cell invasion in vitro and potently reduced the size of flank tumors in vivo Our findings indicate that HPSE in malignant brain tumors affects both the tumor cells themselves and their ECM. In conclusion, HPSE plays a substantial role in childhood brain tumors, by contributing to tumor aggressiveness and thereby represents a potential therapeutic target. Mol Cancer Ther; 16(8); 1705-16. ©2017 AACR.

Overexpression of heparanase attenuated TGF-β-stimulated signaling in tumor cells

Heparan sulfate (HS) mediates the activity of various growth factors including TGF-β. Heparanase is an endo-glucuronidase that specifically cleaves and modifies HS structure. In this study, we examined the effect of heparanase expression on TGF-β1-dependent signaling activities. We found that overexpression of heparanase in human tumor cells (i.e., Fadu pharyngeal carcinoma, MCF7 breast carcinoma) attenuated TGF-β1-stimulated Smad phosphorylation and led to a slower cell proliferation. TGF-β1-stimulated Akt and Erk phosphorylation was also affected in the heparanase overexpression cells. This effect involved the enzymatic activity of heparanase, as overexpression of mutant inactive heparanase did not affect TGF-β1 signaling activity. Analysis of HS isolated from Fadu cells revealed an increase in sulfation of the HS that had a rapid turnover in cells overexpressing heparanase. It appears that the structural alterations of HS affect the ability of TGF-β1 to signal via its receptors and elicit a growth response. Given that heparanase expression promotes tumor growth in most cancers, this finding highlights a crosstalk between heparanase, HS, and TGF-β1 function in tumorigenesis.

Lapatinib resistance in HER2+ cancers: latest findings and new concepts on molecular mechanisms

In the era of new and mostly effective molecular targeted therapies, human epidermal growth factor receptor 2 positive (HER2+) cancers are still intractable diseases. Lapatinib, a dual epidermal growth factor receptor (EGFR) and HER2 tyrosine kinase inhibitor, has greatly improved breast cancer prognosis in recent years after the initial introduction of trastuzumab (Herceptin). However, clinical evidence indicates the existence of both primary unresponsiveness and secondary lapatinib resistance, which leads to the failure of this agent in HER2+ cancer patients. It remains a major clinical challenge to target the oncogenic pathways with drugs having low resistance. Multiple pathways are involved in the occurrence of lapatinib resistance, including the pathways of receptor tyrosine kinase, non-receptor tyrosine kinase, autophagy, apoptosis, microRNA, cancer stem cell, tumor metabolism, cell cycle, and heat shock protein. Moreover, understanding the relationship among these mechanisms may contribute to future tumor combination therapies. Therefore, it is of urgent necessity to elucidate the precise mechanisms of lapatinib resistance and improve the therapeutic use of this agent in clinic. The present review, in the hope of providing further scientific support for molecular targeted therapies in HER2+ cancers, discusses about the latest findings and new concepts on molecular mechanisms underlying lapatinib resistance.

Heparanase: a rainbow pharmacological target associated to multiple pathologies including rare diseases

In recent years, heparanase has attracted considerable attention as a promising target for innovative pharmacological applications. Heparanase is a multifaceted protein endowed with enzymatic activity, as an endo-β-D-glucuronidase, and nonenzymatic functions. It is responsible for the cleavage of heparan sulfate side chains of proteoglycans, resulting in structural alterations of the extracellular matrix. Heparanase appears to be involved in major human diseases, from the most studied tumors to chronic inflammation, diabetic nephropathy, bone osteolysis, thrombosis and atherosclerosis, in addition to more recent investigation in various rare diseases. The present review provides an overview on heparanase, its biological role, inhibitors and possible clinical applications, covering the latest findings in these areas.

Multiple genomic signatures of selection in goats and sheep indigenous to a hot arid environment

Goats and sheep are versatile domesticates that have been integrated into diverse environments and production systems. Natural and artificial selection have shaped the variation in the two species, but natural selection has played the major role among indigenous flocks. To investigate signals of natural selection, we analyzed genotype data generated using the caprine and ovine 50K SNP BeadChips from Barki goats and sheep that are indigenous to a hot arid environment in Egypt's Coastal Zone of the Western Desert. We identify several candidate regions under selection that spanned 119 genes. A majority of the genes were involved in multiple signaling and signal transduction pathways in a wide variety of cellular and biochemical processes. In particular, selection signatures spanning several genes that directly or indirectly influenced traits for adaptation to hot arid environments, such as thermo-tolerance (melanogenesis) (FGF2, GNAI3, PLCB1), body size and development (BMP2, BMP4, GJA3, GJB2), energy and digestive metabolism (MYH, TRHDE, ALDH1A3), and nervous and autoimmune response (GRIA1, IL2, IL7, IL21, IL1R1) were identified. We also identified eight common candidate genes under selection in the two species and a shared selection signature that spanned a conserved syntenic segment to bovine chromosome 12 on caprine and ovine chromosomes 12 and 10, respectively, providing, most likely, the evidence for selection in a common environment in two different but closely related species. Our study highlights the importance of indigenous livestock as model organisms for investigating selection sweeps and genome-wide association mapping.

A Polymorphism in the FGFR4 Gene Is Associated With Risk of Neuroblastoma and Altered Receptor Degradation

BACKGROUND

Outcomes for children with high-risk neuroblastoma are poor, and improved understanding of the mechanisms underlying neuroblastoma pathogenesis, recurrence, and treatment resistance will lead to improved outcomes. Aberrant growth factor receptor expression and receptor tyrosine kinase signaling are associated with the pathogenesis of many malignancies. A germline polymorphism in the FGFR4 gene is associated with increased receptor expression and activity and with decreased survival, treatment resistance, and aggressive disease for many malignancies. We therefore investigated the role of this FGFR4 polymorphism in neuroblastoma pathogenesis.

MATERIALS AND METHODS

Germline DNA from neuroblastoma patients and matched controls was assessed for the FGFR4 Gly/Arg388 polymorphism by RT-PCR. Allele frequencies were assessed for association with neuroblastoma patient outcomes and prognostic features. Degradation rates of the FGFR4 Arg388 and Gly388 receptors and rates of receptor internalization into the late endosomal compartment were measured.

RESULTS

Frequency of the FGFR4 AA genotype and the prevalence of the A allele were significantly higher in patients with neuroblastoma than in matched controls. The Arg388 receptor demonstrated slower degradation than the Gly388 receptor in neuroblastoma cells and reduced internalization into multivesicular bodies.

CONCLUSIONS

The FGFR4 Arg388 polymorphism is associated with an increased prevalence of neuroblastoma in children, and this association may be linked to differences in FGFR4 degradation rates. Our study provides the first evidence of a role for FGFR4 in neuroblastoma, suggesting that FGFR4 genotype and the pathways regulating FGFR4 trafficking and degradation may be relevant for neuroblastoma pathogenesis.

Syntenin and syndecan in the biogenesis of exosomes

Cells communicate with their environment in various ways, including by secreting vesicles. Secreted vesicles are loaded with proteins, lipids and RNAs that compose 'a signature' of the cell of origin and potentially can reprogram recipient cells. Secreted vesicles recently gained in interest for medicine. They represent potential sources of biomarkers that can be collected from body fluids and, by disseminating pathogenic proteins, might also participate in systemic diseases like cancer, atherosclerosis and neurodegeneration. The mechanisms controlling the biogenesis and the uptake of secreted vesicles are poorly understood. Some of these vesicles originate from endosomes and are called 'exosomes'. In this review, we recapitulate recent insight on the role of the syndecan (SDC) heparan sulphate proteoglycans, the small intracellular adaptor syntenin and associated regulators in the biogenesis and loading of exosomes with cargo. SDC-syntenin-associated regulators include the endosomal sorting complex required for transport accessory component ALG-2-interacting protein X, the small GTPase adenosine 5'-diphosphate-ribosylation factor 6, the lipid-modifying enzyme phospholipase D2 and the endoglycosidase heparanase. All these molecules appear to support the budding of SDC-syntenin and associated cargo into the lumen of endosomes. This highlights a major mechanism for the formation of intraluminal vesicles that will be released as exosomes.

Glycosaminoglycans affect heparanase location in CHO cell lines

Glycosaminoglycans (GAG) play a ubiquitous role in tissues and cells. In eukaryotic cells, heparan sulfate (HS) is initially degraded by an endo-β-glucuronidase called heparanase-1 (HPSE). HS oligosaccharides generated by the action of HPSE intensify the activity of signaling molecules, activating inflammatory response, tumor metastasis, and angiogenesis. The aim of the present study was to understand if sulfated GAG could modulate HPSE, since the mechanisms that regulate HPSE have not been completely defined. CHO-K1 cells were treated with 4-methylumbelliferone (4-MU) and sodium chlorate, to promote total inhibition of GAG synthesis, and reduce the sulfation pattern, respectively. The GAG profile of the wild CHO-K1 cells and CHO-745, deficient in xylosyltransferase, was determined after [(35)S]-sulfate labeling. HPSE expression was determined via real-time quantitative polymerase chain reaction. Total ablation of GAG with 4-MU in CHO-K1 inhibited HPSE expression, while the lack of sulfation had no effect. Interestingly, 4-MU had no effect in CHO-745 cells for these assays. In addition, a different enzyme location was observed in CHO-K1 wild-type cells, which presents HPSE mainly in the extracellular matrix, in comparison with the CHO-745 mutant cells, which is found in the cytoplasm. In view of our results, we can conclude that GAG are essential modulators of HPSE expression and location. Therefore, GAG profile could impact cell behavior mediated by the regulation of HPSE.

Heparanase mediates a novel mechanism in lapatinib-resistant brain metastatic breast cancer

Heparanase (HPSE) is the dominant mammalian endoglycosidase and important tumorigenic, angiogenic, and pro-metastatic molecule. Highest levels of HPSE activity have been consistently detected in cells possessing highest propensities to colonize the brain, emphasizing the therapeutic potential for targeting HPSE in brain metastatic breast cancer (BMBC). Lapatinib (Tykerb) is a small-molecule and dual inhibitor of human epidermal growth factor receptor1 and 2 (EGFR and HER2, respectively) which are both high-risk predictors of BMBC. It was approved by the US Food and Drug Administration for treatment of patients with advanced or metastatic breast cancer. However, its role is limited in BMBC whose response rates to lapatinib are significantly lower than those for extracranial metastasis. Because HPSE can affect EGFR phosphorylation, we examined Roneparstat, a non-anticoagulant heparin with potent anti-HPSE activity, to inhibit EGFR signaling pathways and BMBC onset using lapatinib-resistant clones generated from HER2-transfected, EGFR-expressing MDA-MB-231BR cells. Cell growth, EGFR pathways, and HPSE targets were assessed among selected clones in the absence or presence of Roneparstat and/or lapatinib. Roneparstat overcame lapatinib resistance by inhibiting pathways associated with EGFR tyrosine residues that are not targeted by lapatinib. Roneparstat inhibited the growth and BMBC abilities of lapatinib-resistant clones. A molecular mechanism was identified by which HPSE mediates an alternative survival pathway in lapatinib-resistant clones and is modulated by Roneparstat. These results demonstrate that the inhibition of HPSE-mediated signaling plays important roles in lapatinib resistance, and provide mechanistic insights to validate the use of Roneparstat for novel BMBC therapeutic strategies.

The Role of Heparanase and Sulfatases in the Modification of Heparan Sulfate Proteoglycans within the Tumor Microenvironment and Opportunities for Novel Cancer Therapeutics

Heparan sulfate proteoglycans (HSPGs) are an integral and dynamic part of normal tissue architecture at the cell surface and within the extracellular matrix. The modification of HSPGs in the tumor microenvironment is known to result not just in structural but also functional consequences, which significantly impact cancer progression. As substrates for the key enzymes sulfatases and heparanase, the modification of HSPGs is typically characterized by the degradation of heparan sulfate (HS) chains/sulfation patterns via the endo-6-O-sulfatases (Sulf1 and Sulf2) or by heparanase, an endo-glycosidase that cleaves the HS polymers releasing smaller fragments from HSPG complexes. Numerous studies have demonstrated how these enzymes actively influence cancer cell proliferation, signaling, invasion, and metastasis. The activity or expression of these enzymes has been reported to be modified in a variety of cancers. Such observations are consistent with the degradation of normal architecture and basement membranes, which are typically compromised in metastatic disease. Moreover, recent studies elucidating the requirements for these proteins in tumor initiation and progression exemplify their importance in the development and progression of cancer. Thus, as the influence of the tumor microenvironment in cancer progression becomes more apparent, the focus on targeting enzymes that degrade HSPGs highlights one approach to maintain normal tissue architecture, inhibit tumor progression, and block metastasis. This review discusses the role of these enzymes in the context of the tumor microenvironment and their promise as therapeutic targets for the treatment of cancer.

Heparanase is a key player in renal fibrosis by regulating TGF-β expression and activity

Epithelial-mesenchymal transition (EMT) of tubular cells is one of the mechanisms which contribute to renal fibrosis and transforming growth factor-β (TGF-β) is one of the main triggers. Heparanase (HPSE) is an endo-β-D-glucuronidase that cleaves heparan-sulfate thus regulating the bioavailability of growth factors (FGF-2, TGF-β). HPSE controls FGF-2-induced EMT in tubular cells and is necessary for the development of diabetic nephropathy in mice. The aim of this study was to investigate whether HPSE can modulate the expression and the effects of TGF-β in tubular cells. First we proved that the lack of HPSE or its inhibition prevents the increased synthesis of TGF-β by tubular cells in response to pro-fibrotic stimuli such as FGF-2, advanced glycosylation end products (AGE) and albumin overload. Second, since TGF-β may derive from sources different from tubular cells, we investigated whether HPSE modulates tubular cell response to exogenous TGF-β. HPSE does not prevent EMT induced by TGF-β although it slows its onset; indeed in HPSE-silenced cells the acquisition of a mesenchymal phenotype does not develop as quickly as in wt cells. Additionally, TGF-β induces an autocrine loop to sustain its signal, whereas the lack of HPSE partially interferes with this autocrine loop. Overall these data confirm that HPSE is a key player in renal fibrosis since it interacts with the regulation and the effects of TGF-β. HPSE is needed for pathological TGF-β overexpression in response to pro-fibrotic factors. Furthermore, HPSE modulates TGF-β-induced EMT: the lack of HPSE delays tubular cell transdifferentiation, and impairs the TGF-β autocrine loop.

Heparanase 2, mutated in urofacial syndrome, mediates peripheral neural development in Xenopus

Urofacial syndrome (UFS; previously Ochoa syndrome) is an autosomal recessive disease characterized by incomplete bladder emptying during micturition. This is associated with a dyssynergia in which the urethral walls contract at the same time as the detrusor smooth muscle in the body of the bladder. UFS is also characterized by an abnormal facial expression upon smiling, and bilateral weakness in the distribution of the facial nerve has been reported. Biallelic mutations in HPSE2 occur in UFS. This gene encodes heparanase 2, a protein which inhibits the activity of heparanase. Here, we demonstrate, for the first time, an in vivo developmental role for heparanase 2. We identified the Xenopus orthologue of heparanase 2 and showed that the protein is localized to the embryonic ventrolateral neural tube where motor neurons arise. Morpholino-induced loss of heparanase 2 caused embryonic skeletal muscle paralysis, and morphant motor neurons had aberrant morphology including less linear paths and less compactly-bundled axons than normal. Biochemical analyses demonstrated that loss of heparanase 2 led to upregulation of fibroblast growth factor 2/phosphorylated extracellular signal-related kinase signalling and to alterations in levels of transcripts encoding neural- and muscle-associated molecules. Thus, a key role of heparanase 2 is to buffer growth factor signalling in motor neuron development. These results shed light on the pathogenic mechanisms underpinning the clinical features of UFS and support the contention that congenital peripheral neuropathy is a key feature of this disorder.

Heparan sulfate proteoglycans and heparin regulate melanoma cell functions

BACKGROUND

The solid melanoma tumor consists of transformed melanoma cells, and the associated stromal cells including fibroblasts, endothelial cells, immune cells, as well as, soluble macro- and micro-molecules of the extracellular matrix (ECM) forming the complex network of the tumor microenvironment. Heparan sulfate proteoglycans (HSPGs) are an important component of the melanoma tumor ECM. Importantly, there appears to be both a quantitative and a qualitative shift in the content of HSPGs, in parallel to the nevi-radial growth phase-vertical growth phase melanoma progression. Moreover, these changes in HSPG expression are correlated to modulations of key melanoma cell functions.

SCOPE OF REVIEW

This review will critically discuss the roles of HSPGs/heparin in melanoma development and progression.

MAJOR CONCLUSIONS

We have correlated HSPGs' expression and distribution with melanoma cell signaling and functions as well as angiogenesis.

GENERAL SIGNIFICANCE

The current knowledge of HSPGs/heparin biology in melanoma provides a foundation we can utilize in the ongoing search for new approaches in designing anti-tumor therapy. This article is part of a Special Issue entitled Matrix-mediated cell behaviour and properties.

Change is in the air: the hypoxic induction of phenotype switching in melanoma

Melanoma cells can switch from a highly proliferative, less invasive state to a highly invasive, less proliferative state, a phenomenon termed phenotype switching. This results in a highly heterogenous tumor, where a slow-growing, aggressive population of cells may resist tumor therapy, and it predicts tumor recurrence. Here we discuss the observation made by Widmer et al. that hypoxia may drive phenotype switching.

Heparan sulfate mediates trastuzumab effect in breast cancer cells

Background

Trastuzumab is an antibody widely used in the treatment of breast cancer cases that test positive for the human epidermal growth factor receptor 2 (HER2). Many patients, however, become resistant to this antibody, whose resistance has become a major focus in breast cancer research. But despite this interest, there are still no reliable markers that can be used to identify resistant patients. A possible role of several extracellular matrix (ECM) components—heparan sulfate (HS), Syn-1(Syndecan-1) and heparanase (HPSE1)—in light of the influence of ECM alterations on the action of several compounds on the cells and cancer development, was therefore investigated in breast cancer cell resistance to trastuzumab.

Methods

The cDNA of the enzyme responsible for cleaving HS chains from proteoglycans, HPSE1, was cloned in the pEGFP-N1 plasmid and transfected into a breast cancer cell lineage. We evaluated cell viability after trastuzumab treatment using different breast cancer cell lines. Trastuzumab and HS interaction was investigated by confocal microscopy and Fluorescence Resonance Energy Transfer (FRET). The profile of sulfated glycosaminoglycans was also investigated by [³⁵S]-sulfate incorporation. Quantitative RT-PCR and immunofluorescence were used to evaluate HPSE1, HER2 and Syn-1 mRNA expression. HPSE1 enzymatic activity was performed using biotinylated heparan sulfate.

Results

Breast cancer cell lines responsive to trastuzumab present higher amounts of HER2, Syn-1 and HS on the cell surface, but lower levels of secreted HS. Trastuzumab and HS interaction was proven by FRET analysis. The addition of anti-HS to the cells or heparin to the culture medium induced resistance to trastuzumab in breast cancer cells previously sensitive to this monoclonal antibody. Breast cancer cells transfected with HPSE1 became resistant to trastuzumab, showing lower levels of HER2, Syn-1 and HS on the cell surface. In addition, HS shedding was increased significantly in these resistant cells.

Conclusion

Trastuzumab action is dependent on the availability of heparan sulfate on the surface of breast cancer cells. Furthermore, our data suggest that high levels of heparan sulfate shed to the medium are able to capture trastuzumab, blocking the antibody action mediated by HER2. In addition to HER2 levels, heparan sulfate synthesis and shedding determine breast cancer cell susceptibility to trastuzumab.

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

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

Heparanase-induced GEF-H1 signaling regulates the cytoskeletal dynamics of brain metastatic breast cancer cells

Heparanase is the only mammalian endoglycosidase which has been widely implicated in cancer because of its capability to degrade heparan sulfate chains of heparan sulfate proteoglycans (HSPG). Specifically, the cell surface HSPG syndecan-1 and -4 (SDC1 and SDC4) are modulators of growth factor action, and SDC4 is implicated in cell adhesion as a key member of focal adhesion complexes. We hypothesized that extracellular heparanase modulates brain metastatic breast cancer (BMBC) cell invasiveness by affecting cytoskeletal dynamics, SDC4 carboxy-terminal-associated proteins, and downstream targets. We used two independently derived human BMBC cell systems (MB-231BR and MB-231BR3), which possess distinct cellular morphologies and properties. Highly aggressive spindle-shaped 231BR3 cells changed to a round cell morphology associated with expression of the small GTPase guanine nucleotide exchange factor-H1 (GEF-H1). We showed that GEF-H1 is a new component of the SDC4 signaling complex in BMBC cells. Treatment with heparanase resulted in regulation of the SDC4/protein kinase C α axis while maintaining a constitutive GEF-H1 level. Third, GEF-H1 knockdown followed by cell exposure to heparanase caused a significant regulation of activities of Rac1 and RhoA, which are GEF-H1 targets and fundamental effectors in cell plasticity control. Fourth, L-heparanase augmented expression of β1 integrin in BMBC cells and of vascular cell adhesion molecule 1 (VCAM1; the major β1 integrin receptor) in human brain microvascular endothelial cells. Finally, using a newly developed blood-brain barrier in vitro model, we show that BMBC cell transmigration was significantly reduced in GEF-H1 knockdown cells. These findings implicate heparanase in mechanisms of cytoskeletal dynamics and in the cross-talk between tumor cells and vascular brain endothelium. They are of relevance because they elucidate molecular events in the initial steps leading to BMBC onset and capturing distinct roles of latent and active heparanase in the brain microenvironment.

Gekko-sulfated glycopeptide inhibits tumor angiogenesis by targeting basic fibroblast growth factor

Basic fibroblast growth factor (bFGF) is a therapeutic target of anti-angiogenesis. Here, we report that a novel sulfated glycopeptide derived from Gekko swinhonis Guenther (GSPP), an anticancer drug in traditional Chinese medicine, inhibits tumor angiogenesis by targeting bFGF. GSPP significantly decreased the production of bFGF in hepatoma cells by suppressing early growth response-1. GSPP inhibited the release of bFGF from extracellular matrix by blocking heparanase enzymatic activity. Moreover, GSPP competitively inhibited bFGF binding to heparin/heparan sulfate via direct binding to bFGF. Importantly, GSPP abrogated the bFGF-stimulated proliferation and migration of endothelial cells, whereas it had no inhibitory effect on endothelial cells in the absence of bFGF. Further study revealed that GSPP prevented bFGF-induced neovascularization and inhibited tumor angiogenesis and tumor growth in a xenograft mouse model. These results demonstrate that GSPP inhibits tumor angiogenesis by blocking bFGF production, release from the extracellular matrix, and binding to its low affinity receptor, heparin/heparan sulfate.

Methylene blue photodynamic therapy in malignant melanoma decreases expression of proliferating cell nuclear antigen and heparanases

BACKGROUND

Malignant melanoma (MM) is a very aggressive tumour. Although surgical excision of MM in the early stages has a very good prognosis, it often fails to completely inhibit tumour progression. Methylene blue photodynamic therapy (MB-PDT) is a technique that induces tissue damage by reactive oxygen species (ROS).

AIM

To investigate the efficacy of and potential use of MB-PDT in restraining the aggressiveness of MM by analysing levels of proliferating cell nuclear antigen (PCNA) and heparanase (HPSE, a molecular marker of cell invasion) in a mouse model.

METHODS

Expression of PCNA and two HPSE isoforms were analysed using immunohistochemistry (IHC) after MB-PDT in mice. Tumour volume and weight were also measured.

RESULTS

Two treatments with MB-PDT promoted a decrease of 99% decrease in tumour volume and 75% in tumour weight compared with untreated mice (P < 0.05). Using IHC, a decrease in expression of 75% for PCNA and 95% for both HPSE isoforms (P < 0.05) was found.

CONCLUSION

MB-PDT is a cheap and efficient method of decreasing MM volume and thus disease progression. This reduction is mediated by downregulation of PCNA and heparanases.

Heparanase and syndecan-1 interplay orchestrates fibroblast growth factor-2-induced epithelial-mesenchymal transition in renal tubular cells

The epithelial-mesenchymal transition (EMT) of proximal tubular epithelial cells (PTECs) into myofibroblasts contributes to the establishment of fibrosis that leads to end stage renal disease. FGF-2 induces EMT in PTECs. Because the interaction between FGF-2 and its receptor is mediated by heparan sulfate (HS) and syndecans, we speculated that a deranged HS/syndecans regulation impairs FGF-2 activity. Heparanase is crucial for the correct turnover of HS/syndecans. The aim of the present study was to assess the role of heparanase on epithelial-mesenchymal transition induced by FGF-2 in renal tubular cells. In human kidney 2 (HK2) PTEC cultures, although FGF-2 induces EMT in the wild-type clone, it is ineffective in heparanase-silenced cells. The FGF-2 induced EMT is through a stable activation of PI3K/AKT which is only transient in heparanase-silenced cells. In PTECs, FGF-2 induces an autocrine loop which sustains its signal through multiple mechanisms (reduction in syndecan-1, increase in heparanase, and matrix metalloproteinase 9). Thus, heparanase is necessary for FGF-2 to produce EMT in PTECs and to sustain FGF-2 intracellular signaling. Heparanase contributes to a synergistic loop for handling syndecan-1, facilitating FGF-2 induced-EMT. In conclusion, heparanase plays a role in the tubular-interstitial compartment favoring the FGF-2-dependent EMT of tubular cells. Hence, heparanase is an interesting pharmacological target for the prevention of renal fibrosis.

A spoonful of sugar makes the melanoma go: the role of heparan sulfate proteoglycans in melanoma metastasis

Heparan sulfate proteoglycans (HSPGs) have been shown to regulate signaling in many systems and are of increasing interest in cancer. While these are not the only sugars to drive melanoma metastasis, HSPGs play important roles in driving metastatic signaling cascades in melanoma. The ability of these proteins to modulate ligand-receptor interactions in melanoma has been quite understudied. Recent data from several groups indicate the importance of these ligands in modulating key signaling pathways including Wnt and fibroblast growth factor (FGF) signaling. In this review, we summarize the current knowledge regarding the structure and function of these proteoglycans and their role in melanoma. Understanding how HSPGs modulate signaling in melanoma could lead to new therapeutic approaches via the dampening or heightening of key signaling pathways.

Modulation of GEF-H1 induced signaling by heparanase in brain metastatic melanoma cells

Mechanisms of brain metastatic melanoma (BMM) remain largely unknown. Understanding the modulation of signaling pathways that alter BMM cell invasion and metastasis is critical to develop new therapies for BMM. Heparanase has been widely implicated in cancer and is the dominant mammalian endoglycosidase which degrades heparan sulfate chains of proteoglycans (HSPG) including syndecans (SDCs). Recent findings also indicate that heparanase possesses non-enzymatic functions in its latent form. We hypothesized that extracellular heparanase modulates BMM cell signaling by involving SDC1/4 carboxy terminal-associated proteins and downstream targets. We digested BMM cell surface HS with human recombinant active or latent heparanase to delineate their effects on cytoskeletal dynamics and cell invasiveness. We identified the small GTPase guanine nucleotide exchange factor-H1 (GEF-H1) as a new component of a SDC signaling complex that is differentially expressed in BMM cells compared to corresponding non-metastatic counterparts. Second, knockdown of GEF-H1, SDC1, or SDC4 decreased BMM cell invasiveness and GEF-H1 modulated small GTPase activity of Rac1 and RhoA in conjunction with heparanase treatment. Third, both active and latent forms of heparanase affected Rac1 and RhoA activity; notably increasing RhoA activity. Both forms of heparanase were found to mediate the expression and subcellular localization of GEF-H1, and treatment of BMM with latent heparanase modulated SDC1/4 gene expression. Finally, treatment with exogenous heparanase downregulated BMM cell invasion. These studies indicate the relevance of heparanase signaling pathways in BMM progression, and provide insights into the molecular mechanisms regulating HSPG signaling in response to exogenous heparanase.