Specific targeting of ovarian tumor-associated macrophages by large, anionic nanoparticles

Abstract

Significance Tumor-associated macrophages (TAMs) are abundant in tumor microenvironments and are predominantly immunosuppressive. The ratio between immunosuppressive M2 TAMs and proinflammatory M1 TAMs correlates with worse outcomes for many cancers, including ovarian cancer. TAMs are potential targets for immunotherapy, and here we show that, when relatively large (>100-nm) anionic nanoparticles are administered intraperitoneally (i.p.), they selectively accumulate in TAMs with high efficiency (>60% of injected dose). The composition of particles that achieve this targeting appears to be quite flexible. Thus, based on our results, many formulations can now be tested for targeted immunotherapy of ovarian cancer and other cancers of the i.p. cavity.