SUPPORTED BIOMIMETIC MEMBRANES TO STUDY THE SURFACE INTERACTIONS BETWEEN CANCER EXTRACELLULAR VESICLES AND HUMAN PRIMARY STEM CELLS

Abstract

Cancer derived extracellular vesicles (cEVs) have been recognized as important modulators of intercellular communication within the tumor microenvironment. Two main cEV subpopulations, microvesicles (MVs) and exosomes (EXOs), facilitate the transfer of information between cancer and non-cancer cells, which has been determined to be a major factor contributing to cancer progression. For instance, previous research showed that cEVs induce proangiogenic activity and myofibroblast differentiation in adipose derived stem cells (ADSCs), further promoting their role in metastasis. However, in most of the studies, the interactions leading to malignant outcomes induced by cEVs, remained unexplored. One limitation is the lack of techniques available to distinguish surface interactions from internalization to facilitate the investigation of these specific processes. Towards that end, I present two biomimetic membrane models as tools to facilitate the isolation, study, and screening of blocking strategies of surface interactions between cEVs and ADSCs. These models are hybrid supported lipid bilayers (SLBs), a common biomimetic of cell membranes, but here, I am able to incorporate native components of cEVs and ADSC membranes into these SLBs. Their planar geometry enables the use of surface specific characterization techniques and advanced microscopy for these studies. First, I describe an cEV- SLB (EVSB) that incorporates cEV membrane material, working as an in vitro model of the cEV membrane that allows focused studies of cell interactions with this surface and its chemistry, isolated from effects of cEV cargo delivery. Using this system as a cell culture platform for ADSCs, we found that surface interactions between cEVs surface and ADSCs enhance cell viability, proliferation, adhesion, spreading, and proangiogenic activity, conditions that promote oncogenic activity. In a second embodiment of this platform, I create an ADSCs- SLB (ASB), incorporating components of ADSC membrane, as a tool to study the initial EXO-cell interaction, binding. ASB integration with multi-electrode arrays (MEAs) allows recapitulation and dual detection, optical and electrical, of EXOs binding to ADSCs in a cell-free and label-free manner. Moreover, using these two sensing modes, anti-CD29 antibody was found to reduce EXOs binding to ADSCs, demonstrating the ability of this platform for therapeutic molecule screening and the potential of antibody treatment to mitigate outcomes of EXOs-ADSCs interactions that favor cancer progression. Lastly, these biomimetic membrane platforms are the first cell-free in vitro platforms for the recapitulation and study of surface interactions between cEVs and human primary stem cells compatible with scale-up and multiplexing.