Nucleoside transporter-guided cytarabine-conjugated liposomes for intracellular methotrexate delivery and cooperative choriocarcinoma therapy.

Gestational trophoblastic tumors seriously endanger child productive needs and the health of women in childbearing age. Nanodrug-based therapy mediated by transporters provides a novel strategy for the treatment of trophoblastic tumors. Focusing on the overexpression of human equilibrative nucleoside transporter 1 (ENT1) on the membrane of choriocarcinoma cells (JEG-3), cytarabine (Cy, a substrate of ENT1)-grafted liposomes (Cy-Lipo) were introduced for the targeted delivery of methotrexate (Cy-Lipo@MTX) for choriocarcinoma therapy in this study. ENT1 has a high affinity for Cy-Lipo and can mediate the endocytosis of the designed nanovehicles into JEG-3 cells. The ENT1 protein maintains its transportation function through circulation and regeneration during endocytosis. Therefore, Cy-Lipo-based formulations showed high tumor accumulation and retention in biodistribution studies. More importantly, the designed DSPE-PEG2k-Cy conjugation exhibited a synergistic therapeutic effect on choriocarcinoma. Finally, Cy-Lipo@MTX exerted an extremely powerful anti-choriocarcinoma effect with fewer side effects. This study suggests that the overexpressed ENT1 on choriocarcinoma cells holds great potential as a high-efficiency target for the rational design of active targeting nanotherapeutics.