Glycoliposomes target lymphatic dendritic cells in a size-dependent manner to activate natural killer T cells against breast tumors.

Glycolipids have high potential for activating natural killer T (NKT) cells to mediate robust antitumor responses. However, critical challenges, such as low baseline NKT cell counts and the risk of unintentionally engaging immunosuppressive NKT subsets that dampen immune activation, have limited their clinical efficacy. Because antitumor NKT cells are functionalized by dendritic cells (DCs) in lymph nodes, targeting these cells is the key to selective antitumor NKT activation. Here, we developed size-modulated glycoliposomes using the potent glycolipid RK-163 (RK) for selectively targeting lymphatic DCs and promoting strong antitumor efficacy. Our results showed that RK glycoliposomes (RK-lipo) with 100 nm diameter achieved superior lymph node accumulation and DC uptake, leading to high IFN-γ secretion, expansion of NKT cell populations in lymph nodes, and reduction of anti-inflammatory signals. Furthermore, we confirmed an increased level of NKT cells in tumors after treatment with 100 nm RK-lipo, enhancing antitumor immunity in a triple-negative breast cancer (TNBC) murine model. Thus, the 100 nm RK-lipo suppressed the growth of orthotopic breast tumors, significantly extending survival with reduced adverse effects. These findings support the potential of targeting DCs with glycoliposomes to promote NKT cell activation, which provides a promising strategy for effective anti-tumor immunotherapy.