Category: Drug Target Strategies
Breast cancer (BCa) causes mortality mainly due to metastasis and recurrence. Triple negative breast cancer (TNBC) is an aggressive sub-set of BCa which commonly metastasises to the lungs, liver, brain and bone. Extracellular matrix (ECM) is a dynamic and versatile part of the cell microenvironment which regularly interacts with cell membrane receptors, resulting in the regulation of cell proliferation, migration, invasion and metastasis. Focal adhesion kinase (FAK) is a signaling molecule regulated in tumour progression and metastasis and is also a key mediator in BCa cell survival. By studying the interactions of TNBC cells with the surrounding ECM and key downstream signaling pathways such as FAK, an improved understanding of the impact of these factors on BCa biology and therapy was sought.
The aims of this project were to determine whether 1.) the presence of ECM components plays a major role in FAK expression and activation in TNBC and 2.) the presence of FAK inhibitors affects the FAK expression and activation levels in the presence and absence of ECM. The TNBC cell line, MDA-MB-231, was grown with and without Collagen IV (ECM protein), at concentrations 10 - 250µg/mL incubated over a period of 8 – 48hr. FAK inhibitor Y15, which targets the Y397 auto-phosphorylation site of the FAK molecule, was administered at 14 (IC90), 8 (IC50) and 4µM (IC10), prior to and following cell attachment for comparison. The effect Y15 has on MDA-MB-231 cell cycle and DNA alterations leading to apoptosis were also determined in the absence and presence of Collagen IV.
Y15 did not alter the cell cycle in the absence and presence of Collagen IV, however caused DNA damage in MDA-MB-231 cells, which is an indication of apoptosis. The results obtained by immunofluorescence indicated that there was a significant increase of FAK activation in the presence of Collagen IV without FAK inhibitor addition, for all time points. Addition of Y15 before and after cell attachment, resulted in dose-dependent inhibition in activated FAK levels in MDA-MB-231 cells. In addition, an enlargement in the cell size was noted with the majority of cells containing multi-nucleated structures at 4µM Y15 in the presence of 100µg/mL Collagen IV. In summary, these results suggest a role for Collagen IV in FAK regulation in MDA-MB-231 cells. Further studies will be performed using individual ECM components such as Laminin and ECM combinations, as well as complete ECM Matrigel, to determine how these ECM proteins impact on FAK in TNBC resulting in cell invasion and migration.
Thilini Perera– PhD candidate, Discovery Biology, Griffith Institute for Drug Discovery, Griffith University, Nathan, Queensland, Australia
Discovery Biology, Griffith Institute for Drug Discovery, Griffith University
Nathan, Queensland, Australia
Miss D. F. Thilini Perera (BSc Hon, MSc Hon) is a PhD candidate from Griffith University, Australia. She completed her Bachelor of Science (Honours) in Plant Biotechnology at the University of Sri Jayewardenepura, Sri Lanka in 2012. She started her Master of Science (Honours) in Biotechnology and Molecular Biology at Griffith University in 2014. She joined the Discovery Biology group at Griffith Institute for Drug Discovery (GRIDD) in 2015, to complete her Masters research project on breast cancer. Thilini is now undertaking her PhD project, which is focused on studying focal adhesion kinase (FAK) in triple negative breast cancer, under the supervision of Prof. Vicky Avery (Discovery Biology).