Abstract 4096: Identification of EMT inhibitors using novel zebrafish reporter lines

The Epithelial to Mesenchymal Transition (EMT) plays a crucial role during development and aberrant reactivation of EMT in tumor cells promotes metastasis and drug resistance. Mechanisms that control EMT remain incompletely understood, hampering efforts to target EMT in cancer patients. To identify upstream inducers and downstream effectors of EMT we have developed a novel zebrafish neural crest (NC) EMT reporter line, Tg(snail1b:GFP), for in vivo screening of EMT and cell migration inhibitors. After screening a number of candidate kinase inhibitors for their ability to block NC migration in live Tg(snail1b:GFP) embryos, we found that the AXL receptor tyrosine kinase inhibitor, TP-0903 (HCI-2084), potently blocks hindbrain morphogenesis and cranial NC cell migration. Treatment of embryos at the 3-somite stage with TP-0903 significantly decreases twist1a expression, a key regulator of EMT, blocks differentiation of dlx2a-expressing chondrogenic precursors, and instead promotes the differentiation of mitfa-expressing melanophore precursors that form adjacent to the neural tube. RNA-Seq analysis revealed that TP-0903 treated embryos have a significant upregulation of retinoic acid (RA) signaling. Co-treatment of TP-0903 with DEAB, an RA inhibitor, rescues the hindbrain and NC migration and differentiation defects caused by TP-0903 treatment. We are currently investigating the potential role of AXL in NC cell migration and differentiation, and evaluating TP-0903 as a possible therapy for neuroblastoma, by using the zebrafish neuroblastoma pre-clinical model and human neuroblastoma cells in vitro. Citation Format: Laura Jimenez, Jindong Wang, Cicely Jette, Steven L. Warner, David Bearss, Rodney Stewart. Identification of EMT inhibitors using novel zebrafish reporter lines. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4096. doi:10.1158/1538-7445.AM2015-4096