(143a) Single Particle Tracking of Oncogenic Microvesicle Interactions with Planar, Supported Stem Cell Bilayers

Sustained angiogenesis is a hallmark of breast cancer. Previous data suggests that breast cancer cell-derived microvesicles promote the differentiation of adipose derived stem cells into myofibroblasts.¹ These myofibroblasts, in turn, stimulate tumor angiogenesis via increased proangiogenic factor section and extracellular matrix remodeling.¹ Thus, there appears to be a critical transfer of information from oncogenic microvesicles to stem cells that promotes their cellular transformation and the resulting biological outcome. However, the binding moieties of microvesicles and the mechanisms of triggering cargo release intra- and extracellularly remain unknown. Here, we use single particle tracking techniques to study the interactions of oncogenic microvesicles with stem cell surfaces. Because membrane binding and fusion are ubiquitous ways biomolecules are transported into cells and cellular compartments, our studies characterize these entry steps. A critical feature of this experiment is the development of planar stem cell bilayers inside microfluidic devices, a platform which is compatible with a variety of characterization tools and microscopy methods. With this platform, we are able to monitor the binding and fusion of breast cancer derived microvesicles to chemically-tunable, planar bilayers mimicking stem cell surfaces. In this presentation, we describe this new approach to studies of oncogenic microvesicle entry and delineate the effects of microvesicle-associated integrins and the properties of the extracellular environment (calcium, pH, etc.) on cancer microvesicle binding. Furthermore, single particle tracking was also used to define the mechanism of cancer microvesicle delivery of cargo via membrane fusion. The results indicate the impact of the microenvironment on the binding of cancer microvesicle and cargo delivery to adipose derived stem cells.

Reference

1. Song, Y. H.; Warncke, C.; Choi, S. J.; Choi, S.; Chiou, A. E.; Ling, L.; Liu, H.-Y.; Daniel, S.; Antonyak, M. A.; Cerione, R. A. Breast cancer-derived extracellular vesicles stimulate myofibroblast differentiation and pro-angiogenic behavior of adipose stem cells. Matrix Biology 2016.