The epithelial-mesenchymal transition (EMT) confers mesenchymal properties on epithelial cells and has been closely associated with the acquisition of aggressive traits of breast cancer cells. Recently, a few kinases, such as FYN and c-Met, were reported to participate in regulating EMT. However, the roles of the majority of >700 human kinases in EMT and breast cancer progression are still unknown. Here we carried out human kinase cDNA screens to identify novel regulators of EMT. Many unknown EMT regulators and a few known ones such as PI3K, PDGFRA, FYN and c-Met, were found to up-regulate mesenchymal marker vimentin. Some also increase expression of fibronectin and N-cadherin, as well as EMT transcriptional regulators, such as ZEB1/2, Snail and Slug. At the same time, the cells acquired mesenchymal phenotypes, such as increased migration/invasion activity, enhanced capability to survive and proliferate in growth factor deprivation condition or under drug treatments. Interestingly, FACS analysis also showed a substantial increase in CD44hiCD24low population in kinase-transducted mammary gland epithelial cells. The increase of CD44hi population could be attributed to increase of a CD44 mesenchymal variant - the standard form CD44s and decrease of the epithelial variant CD44 v8-10. And this alternation was associated with down-regulation of ESRP1 and ESRP2, two splicing factors that regulate CD44 splicing and EMT. Furthermore, the mammary gland epithelial cells undergoing EMT showed increase capability of forming mammosphere and differentiating into other lineages, such as osteoblast and adipocyte. Importantly, some of these novel EMT regulators are associated with TNBC, stemness and poor prognostics of human breast cancers. One novel regulator, a poorly studied serine/threonine protein kinase, was tested in vivo and found to be capable of generating primary tumor and metastasis at much higher efficiency. Further study of these novel EMT regulators promises to provide new mechanisms of breast cancer progression, and may also lead to development of new prognostic markers and therapeutics.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A160.

Citation Format: Linna Li, Emily Lu, Jeffrey Chang, Wenliang Li. Characterization of novel regulators for epithelial-mesenchymal transition. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A160.