The bottleneck of cationic antimicrobial peptides as anticancer therapeutics is their limited ability to penetrate cell membranes. Researchers discovered a cyclic decapeptide (termed peptide 1) that serves as a promising lead compound as a new intracellular delivery vehicle for therapeutically effective peptides. When conjugated with another membrane impermeable proapoptotic domain (PAD) peptide, the compound was found to have significantly inhibitory activity in cancer cell lines.