Cell-penetrating peptides that target particular lineages of tumour cells are described in a study published in Nature Communications this week. These agents could provide a good system for delivering anti-cancer molecules to tumour cells.

Cell-penetrating peptides have been previously described but little is known about their specificity for different tumour cell types. In this study, Eisaku Kondo and colleagues show that some cell-penetrating peptides only permeate one or two cell types in culture. Focusing on a peptide that targets leukemia cells in culture, they show that the peptide did not readily penetrate non-cancerous cells. However, they identified a transporter that may be important for uptake of peptides into this cell type. They also showed that a peptide attached to a known tumour suppressor enhanced the death of cells in culture and reduced metastasis of tumours in mice. These findings suggest that these peptides could be used to target specific tumour cell type.