Biallelic Dicer1 Loss Mediated by aP2-Cre Drives Angiosarcoma

Angiosarcoma is an aggressive vascular sarcoma with an extremely poor prognosis. Because of the relative rarity of this disease, its molecular drivers and optimal treatment strategies are obscure. DICER1 is an RNase III endoribonuclease central to miRNA biogenesis, and germline DICER1 mutations result in a cancer predisposition syndrome, associated with an increased risk of many tumor types. Here, we show that biallelic Dicer1 deletion with aP2-Cre drives aggressive and metastatic angiosarcoma independent of other genetically engineered oncogenes or tumor suppressor loss. Angiosarcomas in aP2-Cre;Dicer1 mice histologically and genetically resemble human angiosarcoma. miR-23 target genes, including the oncogenes Ccnd1 as well as Adam19, Plau, and Wsb1 that promote invasiveness and metastasis, were enriched in mouse and human angiosarcoma. These studies illustrate that Dicer1 can function as a traditional loss-of-function tumor suppressor gene, and they provide a fully penetrant animal model for the study of angiosarcoma development and metastasis. Cancer Res; 77(22); 6109-18. ©2017 AACR.