Given the potential tissue damage that
could result from inappropriate cleavage of heparan sulfate (HS), tight regulation of heparanase expression and function are essential. Apart of stimulatory elements along the heparanase promoter, we identified AU-rich element in the 3’ untranslated region that suppresses heparanase gene expression. Regulation at the protein level includes modulation of its cell surface expression, cathepsin L-mediated processing, cellular uptake, secretion, and cytoplasmic vs. nuclear localization. Heparanase also augments cell adhesion and signaling cascades leading to enhanced phosphorylation of selected protein kinases and increased transcription of genes associated with aggressive tumor progression. This function of heparanase appears independent of its enzymatic activity and HS substrate Talazoparib solubility dmso and is mediated by a protein domain localized at the C-terminus (C-domain) of the protein. The C-domain is critical for
heparanase secretion and signaling functions and for maintaining the 3D structure of the active enzyme. The functional repertoire of heparanase is further expanded by its regulation of syndecan clustering and shedding. Studies applying heparanase over-expressing and knock-out mice emphasize its ALK inhibitor role in tissue morphogenesis and as a master regulator of other ECM degrading enzymes. Heparanase is causally involved in inflammation and accelerates colon tumorigenesis associated with inflammatory bowel disease. Inhibitors directed against the C-domain, combined with inhibitors of heparanase enzymatic activity are being developed to halt tumor growth, metastasis, angiogenesis and inflammation. A lead compound (non-anticoagulant glycol-split heparin), highly effective 4-Aminobutyrate aminotransferase against myeloma tumors, was selected toward a clinical trial in cancer patients. O150 Microenvironment-Dependent Support of Self Renewing Ovarian Cancer Stem Cells Karl Skorecki1, Maty Tzukerman 1 1 Department of Molecular Medicine, Rapport Faculty of Medicine, Rambam Medical Center and Technion,
Israel Institute of Technology, Haifa, Israel One of the main stumbling blocks in establishing personalized cancer therapy has been the paucity of pre-clinical experimental models in which the actual cancer cells from a patient can be successfully grown in a manner which mimics growth in the human body for testing of anti-cancer treatments tailored to the individual patient. We have demonstrated that human embryonic stem cells (hESC) – derived microenvironment provide a niche which enables the growth of important subsets of ovarian cancer stem cells, which evade growth in conventional systems. Six different subpopulations of ovarian cancer cells from one patient have been generated and characterized.