Abstract
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.
Original language | English |
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Pages (from-to) | 3946-3957 |
Number of pages | 12 |
Journal | Cancer Research |
Volume | 75 |
Issue number | 18 |
DOIs | |
State | Published - 15 Sep 2015 |
Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2015 American Association for Cancer Research.
Funding
Funders | Funder number |
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Israel Cancer Research Fund | |
Israel Science Foundation | 601/14 |
National Cancer Institute | |
National Institutes of Health | |
National Cancer Institute | R01CA106456 |