A translational study for biomarker identification of PEP-010, a pro-apoptotic peptide restoring apoptosis in cancer models

•PEP-010 is a pro-apoptotic peptide based on a proprietary cell-penetrating and interfering peptide technology for the treatment of advanced solid tumors.•PEP-010 acts by disrupting the interaction between caspase-9 and PP2A, two key proteins involved in apoptosis, a physiological process frequently altered in cancers.•PEP-010 efficiently induces apoptosis in cancer cells.•PEP-010 demonstrates antitumor activity by inhibiting the growth of breast cancer patient-derived xenografts (PDX).•This study establishes cleaved caspase-3 and Ki67 protein expression as two candidate pharmacodynamic (PD) biomarkers for monitoring PEP-010-induced apoptosis in vitro and in vivo. •PEP-010 is a pro-apoptotic peptide disrupting the interaction between caspase-9 and PP2A.•PEP-010 is effective in cell models and in breast cancer patient-derived xenografts (PDX).•Cleaved caspase-3 and Ki67 expression are two candidate pharmacodynamic (PD) biomarkers for PEP-010.