Z-DQMD-FMK is a potent cell-permeable inhibitor of caspase-3. Researchers have shown that expression of a short peptide of 15 amino acids, including DQMD leads to abrogation of the apoptotic cascade, and treatment of cells, expressing the DQMD peptide with two apoptosis inducers, etoposide and sodium nitroprusside blocks cell death by apoptosis. Stable expression of the DQMD peptide leads to protection of cells, following induction of apoptosis and to the outgrowth and enrichment of resistant cell colonies.