While initially thought to be a hindrance for drug delivery, uptake of nanoparticles by myeloid cells is one option for transport to tumor cells. In addition to degradation of material and antigen processing, myeloid cells can function as carriers, transferring their cargo to other cells. While transfer within the population of RAW 264.7 macrophages frequently occurred through cellular bridges (a.k.a. tunneling nanotubes, Figure 1), transfer to cancer cells was through thick cellular connections with elaborate cell-to-cell adhesion sites. Microscopy were used to track intercellular transfer of material, which included nanoparticles, microparticles, and their cargo. Multi-modal imaging was used to track myeloid cells <i>in vivo</i> using a 4T1 breast cancer model. Tumor vasculature was imaged by perfusion of mice with a silicone rubber compound (Microfil®) followed by computed tomographic (CT) evaluation of the tumor vasculature (Figure 2a). Magnetic resonance (MR) imaging of macrophage migration <i>in vivo</i> was indirect through injection of tumor bearing mice with the commercially available emulsion V-Sense (Figure 2b). Overall, this work supports a role for myeloid cells as cell-based carriers of synthetic particles and their cargo, facilitating drug delivery to tumor cells.

Intercellular transport of nanoparticles in myeloid and cancer cells

254th National Meeting (2017)

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