Our previous studies showed that colorectal tumor has high interleukin-4 receptor α (IL-4Rα) expression, whereas adjacent normal tissue has low or no IL-4Rα expression. We also observed that human atherosclerotic plaque-specific peptide-1 (AP1) can specifically target to IL-4Rα. In this study, we investigated the therapeutic efficacy and systemic toxicity of AP1-conjuagted liposomal doxorubicin. AP1 bound more strongly to and was more efficiently internalized into IL-4Rα-overexpressing CT26 cells than CT26 control cells. Selective cytotoxicity experiment revealed that AP1-conjugated liposomal doxorubicin preferentially killed IL-4Rα-overexpressing CT26 cells. AP1-conjugated liposomal doxorubicin administered intravenously into mice produced significant inhibition of tumor growth and showed decreased cardiotoxicity of doxorubicin. These results indicated that AP1-conjugated liposomal doxorubicin has a potent and selective anticancer potential against IL-4Rα-overexpressing colorectal cancer cells, thus providing a model for targeted anticancer therapy.
Keywords: AP1; colorectal cancer; interleukin-4 receptor α; targeted drug delivery.