In previous studies, the focal adhesion-associated scaffolding protein HEF1, also known as NEDD9, has been implicated as a possible dynamic switch between the mesenchymal and amoeboid migration methods of melanoma cancer cells. Management of this switch provides a possible mechanism of control that could potentially open up new strategies for treatments of metastatic cancers. We have sought to investigate whether HEF1’s involvement in cell migration could also be applied to breast cancer. To monitor the switch between the two methods of migration, we decided to monitor activation of the Rac1 and RhoA proteins of the Rho subfamily of GTPases, which are renowned for their roles in actin cytoskeletal dynamics and have been linked to cancer cell invasion. High levels of active Rac1 result in an elongated cell morphology accompanied by mesenchymal cell movement, whereas high active RhoA levels result in a rounded cell morphology accompanied by amoeboid cell movement. Using a series of GST-tag pulldown experiments, we pulled and quantified amounts of active Rac1 and RhoA from an MDA-MB-231LN human breast cancer cell line grown in both 2D and 3D conditions under a HEF1 shRNA knockdown. Our HEF1-reduced cell line shows a decrease in active Rac1 and an increase in active RhoA compared to a control cell line with normal HEF1 levels. With this data, we aim to further substantiate HEF1 as a relevant key player in the balance between mesenchymal and amoeboid dominance in cancer cells.

Citation Format: Brandon Jones, Elena Pugacheva. HEF1 is an important regulator of mesenchymal and amoeboid invasion in breast cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2640. doi:10.1158/1538-7445.AM2013-2640