Targeted hydroxyethyl starch prodrug for inhibiting the growth and metastasis of prostate cancer

Abstract Prostate cancer is one of the most prevalent malignancies among men. Although chemotherapy has been an effective therapeutic approach for treating metastatic prostate cancer, serious undesired side effects have hampered its wide application clinically. In this work, a pH-responsive LHRH-conjugated hydroxyethyl starch-doxorubicin (HES-DOX/LHRH) prodrug was facilely synthesized by conjugating oxidized HES (HES-CHO) with DOX and a LHRH analog through an acid-sensitive Schiff base bond. The resulting prodrug spontaneously self-assembled into nanoscopic micelle with a radius of about 55 nm in an aqueous environment. HES-DOX/LHRH significantly improved the in vivo tissue distribution of drug. Compared to its non-targeted counterpart, targeted HES-DOX/LHRH demonstrated a greater in vitro anti-proliferative capability toward mouse RM-1 prostate cells. More importantly, targeted HES-DOX/LHRH exhibited higher levels of anti-tumor and anti-metastasis activities against an RM-1-xenografted mouse model, with lower systemic toxicity compared to free DOX·HCl and non-targeted HES-DOX. Hence, these results revealed that targeted HES-DOX/LHRH possesses great potential application in clinical chemotherapy of metastatic prostate cancer.