Toowong, Australia

Progen Pharmaceuticals Limited
Toowong, Australia
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Boyango I.,Cancer and Vascular Biology Research Center | Barash U.,Cancer and Vascular Biology Research Center | Naroditsky I.,Rambam Health Care Campus | Li J.-P.,Uppsala University | And 3 more authors.
Cancer Research | Year: 2014

Heparanase has been implicated in cancer but its contribution to the early stages of cancer development is uncertain. In this study, we utilized nontransformed human MCF10A mammary epithelial cells and two genetic mouse models [Hpa-transgenic (Hpa-Tg ) and knockout mice] to explore heparanase function at early stages of tumor development. Heparanase overexpression resulted in significantly enlarged asymmetrical acinar structures, indicating increased cell proliferation and decreased organization. This phenotype was enhanced by coexpression of heparanase variants with a mutant H-Ras gene, which was sufficient to enable growth of invasive carcinoma in vivo. These observations were extended in vivo by comparing the response of Hpa-Tg mice to a classical two-stage 12-dimethylbenz(a)anthracene (DMBA)/12-o- tetradecanoylphorbol-13-acetate (TPA) protocol for skin carcinogenesis. Hpa-Tg mice overexpressing heparanase were far more sensitive than control mice to DMBA/TPA treatment, exhibiting a 10-fold increase in the number and size of tumor lesions. Conversely, DMBA/TPA-induced tumor formation was greatly attenuated in Hpa-KO mice lacking heparanase, pointing to a critical role of heparanase in skin tumorigenesis. In support of these observations, the heparanase inhibitor PG545 potently suppressed tumor progression in this model system. Taken together, our findings establish that heparanase exerts protumorigenic properties at early stages of tumor initiation, cooperating with Ras to dramatically promote malignant development. ©2014 AACR.

Shteingauz A.,Cancer and Vascular Biology Research Center | Boyango I.,Cancer and Vascular Biology Research Center | Naroditsky I.,Rambam Health Care Campus | Hammond E.,Progen Pharmaceuticals Limited | And 4 more authors.
Cancer Research | Year: 2015

Heparanase is the only enzyme in mammals capable of cleaving heparan sulfate, an activity implicated in tumor inflammation, angiogenesis, and metastasis. Heparanase is secreted as a latent enzyme that is internalized and subjected to proteolytic processing and activation in lysosomes. Its role under normal conditions has yet to be understood. Here, we provide evidence that heparanase resides within autophagosomes, where studies in heparanase-deficient or transgenic mice established its contributions to autophagy. The protumorigenic properties of heparanase were found to be mediated, in part, by its proautophagic function, as demonstrated in tumor xenograft models of human cancer and through use of inhibitors of the lysosome (chloroquine) and heparanase (PG545), both alone and in combination. Notably, heparanase-overexpressing cells were more resistant to stress and chemotherapy in a manner associated with increased autophagy, effects that were reversed by chloroquine treatment. Collectively, our results establish a role for heparanase in modulating autophagy in normal and malignant cells, thereby conferring growth advantages under stress as well as resistance to chemotherapy. © 2015 American Association for Cancer Research.

Ostapoff K.T.,University of Texas Southwestern Medical Center | Awasthi N.,University of Texas Southwestern Medical Center | Cenik B.K.,University of Texas Southwestern Medical Center | Hinz S.,University of Texas Southwestern Medical Center | And 4 more authors.
Molecular Cancer Therapeutics | Year: 2013

Aggressive tumor progression, metastasis, and resistance to conventional therapies lead to an extremely poor prognosis for pancreatic ductal adenocarcinoma (PDAC). Heparanase, an enzyme expressed by multiple cell types, including tumor cells in the tumor microenvironment, has been implicated in angiogenesis and metastasis, and its expression correlates with decreased overall survival in PDAC. We evaluated the therapeutic potential of PG545, an angiogenesis and heparanase inhibitor, in experimental PDAC. PG545 inhibited the proliferation, migration, and colony formation of pancreatic cancer cells in vitro at pharmacologically relevant concentrations. Heparanase inhibition also reduced the proliferation of fibroblasts but had only modest effects on endothelial cells in vitro. Furthermore, PG545 significantly prolonged animal survival in intraperitoneal and genetic models (mPDAC: LSL-KrasG12D; Cdkn2alox/lox; p48Cre) of PDAC. PG545 also inhibited primary tumor growth and metastasis in orthotopic and genetic endpoint studies. Analysis of tumor tissue revealed that PG545 significantly decreased cell proliferation, increased apoptosis, reduced microvessel density, disrupted vascular function, and elevated intratumoral hypoxia. Elevated hypoxia is a known driver of collagen deposition and tumor progression; however, tumors from PG545-treated animals displayed reduced collagen deposition and a greater degree of differentiation compared with control or gemcitabine-treated tumors. These results highlight the potent antitumor activity of PG545 and support the further exploration of heparanase inhibitors as a potential clinical strategy for the treatment of PDAC. ©2013 AACR.

Hammond E.,Progen Pharmaceuticals Limited | Brandt R.,vivoPharm | Dredge K.,Progen Pharmaceuticals Limited | Dredge K.,University of Queensland
PLoS ONE | Year: 2012

PG545 is a clinically relevant heparan sulfate (HS) mimetic which, in addition to possessing anti-angiogenic properties, also acts as a heparanase inhibitor which may differentiate its mechanism(s) of action from approved angiogenesis inhibitors. The degradation of HS by heparanase has been strongly implicated in cell dissemination and the metastatic process. Thus, the anti-metastatic activity of PG545 has been linked to the enzymatic function of heparanase - the only endoglycosidase known to cleave HS, an important component of the extracellular matrix (ECM) which represents a potential avenue for therapeutic intervention for certain metastatic cancer indications. Recent concerns raised about the paucity of overall survival as an endpoint in mouse models of clinically relevant metastasis led us to examine the effect of PG545 on the progression of both primary tumor growth and the spontaneously metastasizing disease in the 4T1 syngeneic breast carcinoma model in a non-surgical and surgical (mastectomy) setting. PG545 significantly inhibited primary tumor growth but importantly also inhibited lung metastasis in treated mice, an effect not observed with the tyrosine kinase inhibitor sorafenib. Importantly, PG545 significantly enhanced overall survival compared to vehicle control and the sorafenib group, suggesting PG545's inhibitory effect on heparanase is indeed a critical attribute to induce anti-metastatic activity. In addition to blocking a common angiogenic signalling pathway in tumor cells, the expression of heparanase in the primary tumor and lung was also significantly reduced by PG545 treatment. These results support the ongoing development of PG545 and highlight the potential utility in metastatic disease settings. © 2012 Hammond et al.

Brennan T.V.,Duke University | Lin L.,Duke University | Huang X.,Duke University | Cardona D.M.,Duke University | And 4 more authors.
Blood | Year: 2012

Graft-versus-host disease (GVHD) remains the most common cause of nonrelapse-related morbidity and mortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Although T-cell depletion and intensive immunosuppression are effective in the control of GVHD, they are often associated with higher rates of infection and tumor recurrence. In this study, we showed that heparan sulfate (HS), an extracellular matrix component, can activate Toll-like receptor 4 on dendritic cells in vitro, leading to the enhancement of dendritic cell maturation and alloreactive T-cell responses. We further demonstrated in vivo that serum HS levels were acutely elevated at the onset of clinical GVHD in mice after allo-HSCT. Treatment with the serine protease inhibitor α1-antitrypsin decreased serum levels of HS, leading to a reduction in alloreactive T-cell responses and GVHD severity. Conversely, an HS mimetic that increased serum HS levels accelerated GVHD. In addition, in patients undergoing allo-HSCT for hematologic malignancies, serum HS levels were elevated and correlated with the severity of GVHD. These results identify a critical role for HS in promoting acute GVHD after allo-HSCT, and they suggest that modulation of HS release may have therapeutic potential for the control of clinical GVHD. © 2012 by The American Society of Hematology.

Hammond E.,Progen Pharmaceuticals Limited | Khurana A.,Rochester College | Shridhar V.,Rochester College | Dredge K.,Progen Pharmaceuticals Limited
Frontiers in Oncology | Year: 2014

Heparan sulfate proteoglycans (HSPGs) are an integral and dynamic part of normal tissue architecture at the cell surface and within the extracellular matrix (ECM). The modification of HSPGs in the tumour 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 characterised 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, signalling, invasion and metastasis. The activity or expression of these enzymes have 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 tumour initiation and progression exemplify their importance in the development and progression of cancer. Thus, as the influence of the tumour microenvironment in cancer progression becomes more apparent, the focus on targeting enzymes that degrade HSPGs highlights one approach to maintain normal tissue architecture, inhibit tumour progression and block metastasis. This review discusses the role of these enzymes in the context of the tumour microenvironment and their promise as therapeutic targets for the treatment of cancer. © 2014 Hammond, Khurana, Shridhar and Dredge.

Hammond E.,Progen Pharmaceuticals Limited | Handley P.,Progen Pharmaceuticals Limited | Dredge K.,University of Queensland | Bytheway I.,Progen Pharmaceuticals Limited
FEBS Open Bio | Year: 2013

The tetrasaccharide heparan sulfate (HS) mimetic PG545, a clinical anti-cancer candidate, is an inhibitor of the HS-degrading enzyme heparanase. The kinetics of heparanase inhibition by PG545 and three structural analogues were investigated to understand their modes of inhibition. The cholestanol aglycon of PG545 significantly increased affinity for heparanase and also modified the inhibition mode. For the tetrasaccharides, competitive inhibition was modified to parabolic competition by the addition of the cholestanol aglycon. For the trisaccharides, partial competitive inhibition was modified to parabolic competition. A schematic model to explain these findings is presented. © 2013 The Authors.

Progen Pharmaceuticals Limited | Date: 2014-09-05

The invention relates to novel compounds that have utility as inhibitors of heparan sulfate-binding proteins; compositions comprising the compounds, and use of the compounds and compositions thereof for the antiangiogenic, antimetastatic, anti-inflammatory, antimicrobial, anticoagulant and/or antithrombotic treatment of a mammalian subject.

Progen Pharmaceuticals Limited | Date: 2010-12-03

The invention relates to compounds which are polysulfated oligosaccharide derivatives having activity as inhibitors of heparan sulfate-binding proteins and inhibitors of the enzyme heparanase; methods for the preparation of the compounds; compositions comprising the compounds, and use of the compounds and compositions thereof for the antiangiogenic, antimetastatic, anti-inflammatory, antimicrobial, anticoagulant and/or antithrombotic treatment, lowering of blood triglyceride levels and inhibition of cardiovascular disease of a mammalian subject.

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