Anti-angiogenic therapy using the multi-tyrosine kinase inhibitor Regorafenib enhances tumor progression in a transgenic mouse model of ß-cell carcinogenesis

BACKGROUND: Pancreatic neuroendocrine tumors (PNETs) represent a distinct hypervascularized tumor entity, often diagnosed at metastatic stage. Therapeutic efficacy of anti-angiogenic multi-kinase inhibitors is frequently limited by primary or acquired resistance in vivo. This study aimed to characterize the molecular mode of action as well as resistance mechanisms to the anti-angiogenic multi-tyrosine kinase inhibitor (TKI) Regorafenib in vitro and in …