Abstract
Heparanase, the sole heparan sulfate (HS) degrading endoglycosidase, regulates multiple biological activities that enhance tumor growth, metastasis, angiogenesis, and inflammation. Heparanase accomplishes this by degrading HS and thereby facilitating cell invasion and regulating the bioavailability of heparin-binding proteins. HS mimicking compounds that inhibit heparanase enzymatic activity were examined in numerous preclinical cancer models. While these studies utilized established tumor cell lines, the current study utilized, for the first time, patient-derived xenografts (PDX) which better resemble the behavior and drug responsiveness of a given cancer patient. We have previously shown that heparanase levels are substantially elevated in lung cancer, correlating with reduced patients survival. Applying patient-derived lung cancer xenografts and a potent inhibitor of heparanase enzymatic activity (PG545) we investigated the significance of heparanase in the pathogenesis of lung cancer. PG545 was highly effective in lung cancer PDX, inhibiting tumor growth in >85% of the cases. Importantly, we show that PG545 was highly effective in PDX that did not respond to conventional chemotherapy (cisplatin) and vice versa. Moreover, we show that spontaneous metastasis to lymph nodes is markedly inhibited by PG545 but not by cisplatin. These results reflect the variability among patients and strongly imply that PG545 can be applied for lung cancer therapy in a personalized manner where conventional chemotherapy fails, thus highlighting the potential benefits of developing anti-heparanase treatment modalities for oncology.