Pentapeptide YIGSR-mediated HT-1080 fibrosarcoma cells targeting of adriamycin encapsulated in sterically stabilized liposomes

In the peptide-targeted therapy for cancer, peptides are used to reach a selective and specific target in cancer cells. Peptides are used free or coupled to chemotherapeutic drugs, phagues, proteins, polymers, liposomes, and polymer-grafted liposomes. Using this latter approach, the pentapeptide YIGSR was coupled to the distal end from carboxyl groups of liposome-grafted polyethyleneglycol (PEG) chains (YTGSR-PEG-liposome). As a control, the peptide PEAGD coupled to PEG-liposome was used. The biological activity of YIGSR-PEG-liposome was tested using HT-1080 human fibrosarcoma cells. In adhesion assays, the YIGSR-PEG-liposome coated to plastic plates promoted 30% of the specific cell attachment. In competition assays, YIGSR-PEG-liposome inhibited the specific attachment of cells to laminin-1-coated plates by 25%. Following this, we prepared peptide-PEG-liposomes encapsulating adriamycin (ADR). In vitro cytotoxicity assays against HT-1080 cells gave IC50 values 2.1 times lower for YIGSR-PEG-liposomal ADR in comparison to PEAGD-PEG-liposomal ADR. The free peptide added in excess increased the IC50 value of YIGSR-PEG-liposomal ADR by 72%, while the IC50 value of control liposomal ADR was unaffected, supporting a receptor-mediated mechanism of targeting. In addition, the lower IC50 value is correlated with a higher total of ADR accumulation in the cells. (C) 2004 Wiley Periodicals, Inc.