Most cells need to be attached, through integrins, to a semi-solid meshwork called the extracellular matrix in order to survive. But if peptides with the sequence arginine-glycine-aspartic acid are added, the cells detach and die. The reason was always thought to be a blockade of integrin signalling, but a new mechanism has emerged. It seems that the RGD peptide activates caspases directly inside the cell.
