Galectin-3 (Gal-3), over-expressed on a variety of human tumor cells, is a potential binding site for targeted metastatic prostate cancer therapy. The aim of this study was to develop a G3-C12-mediated drug delivery system based on N-(2-hydroxypropyl) methacrylamide (HPMA) copolymers targeting to Gal-3-expressed human PC-3 prostate carcinoma cells. 5-Fluorouracil (5-Fu), an anti-tumor agent, was selected as a model drug. G3-C12, a binding peptide, which specifically binds to the carbohydrate-recognition domain (CRD) of Gal-3, was attached to HPMA copolymers as a targeting moiety. Compared with non-targeted conjugates (P-Fu), Gal-3-targeted HPMA copolymer-(G3-C12)-5-Fu conjugates (P-(G3-C12)-Fu) displayed a superior intracellular internalization followed by enhanced cytotoxicity and apoptosis-induction. Subsequently, the in vitro migration study on PC-3 cells indicated that P-(G3-C12)-Fu was able to efficiently inhibit the cell migration ability after wounding. On PC-3 tumor-bearing mice model, G3-C12-modified copolymers showed a higher tumor accumulation coupled with a faster clearance from blood circulation than non-modified ones. Finally, Gal-3-targeted conjugates significantly improved the anti-tumor activity of 5-Fu in nude mice bearing PC-3 tumor xenografts. Consequently, G3-C12 would be a promising targeting moiety for cell-specific prostate cancer therapy in future.
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