Post-Translational Modification of the Membrane Type 1 Matrix Metalloproteinase (MT1-MMP) Cytoplasmic Tail Impacts Ovarian Cancer Multicellular Aggregate Dynamics
- ↵* Corresponding author; email: sstack{at}nd.edu
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Author contributions: JY coordinated the study, performed and/or supervised the experiments and wrote the manuscript. WCK performed experiments and analyzed data for Figs. 1,3,5, and 6. AC performed experiments and analyzed data for Fig. 2. ZL assisted with experiments in Figs. 5-6. KQ assisted with experiments in Fig. 2. MSS conceived of the study, analyzed all data, and wrote the manuscript. All authors reviewed the results and approved the final manuscript.
Abstract
Membrane type 1 matrix metalloproteinase (MT1-MMP, MMP-14) is a transmembrane collagenase highly expressed in metastatic ovarian cancer and correlates with poor survival. Accumulating evidence shows that the cytoplasmic tail of MT1-MMP is subjected to phosphorylation, and this post-translational modification regulates enzymatic activity at the cell surface. To investigate the potential role of MT1-MMP cytoplasmic residue Thr567 phosphorylation in regulation of metastasis-associated behaviors, ovarian cancer cells that express low endogenous levels of MT1-MMP were engineered to express wild-type MT1-MMP, a phospho-mimetic mutant (T567E) or a phospho-deficient mutant (T567A). Results show that Thr567 modulation influences behavior of both individual cells and multi-cellular aggregates (MCAs). The acquisition of either wild-type or mutant MT1-MMP expression results in altered cohesion of epithelial sheets and the formation of more compact MCAs relative to parental cells. Cells expressing MT1-MMP-T567E phospho-mimetic mutants exhibit enhanced cell migration. Furthermore, MCAs formed from MT1-MMP-T567E-expressing cells adhere avidly to both intact ex vivo peritoneal explants and 3-dimensional collagen gels. Interaction of these MCAs with peritoneal mesothelium disrupts mesothelial integrity, exposing the sub-mesothelial collagen matrix on which MT1-MMP-T567E MCAs rapidly disperse. Together, these findings suggest that post-translational regulation of the Thr567 in the MT1-MMP cytoplasmic tail may function as a regulatory mechanism to impact ovarian cancer metastatic success.
- Received June 6, 2017.
- Accepted June 27, 2017.
- Copyright © 2017, The American Society for Biochemistry and Molecular Biology
