Transferrin directed delivery of adriamycin to human cells.

Transferrin was covalently conjugated to adriamycin (Trf-adr) by the formation of a schiff base. This conjugate was found to bind to cell membrane trf receptors in a variety of human tumor cell lines. The Trf-adr conjugate was found to be active against sensitive and resistant cell lines e.g. Lovo, HL-60, H-meso and Hep2. It was, however, found that Trf-adr conjugate was more potent against resistant human tumor cell lines as compared to sensitive cell lines (based on cytotoxicity assays). The Trf-adr conjugate was then tested against nude mice bearing human mesothelioma tumors in their peritoneal cavity. The Trf-adr conjugate prolonged the lifespan of advanced tumor bearing nude mice as compared to either adriamycin alone or adriamycin and trf unlinked. Our studies show that trf can be successfully used as an ligand for directing anticancer drugs to human tumor cells.