In summary, this study highlights several important findings in prostate cancer therapy: (i) delivery of BikDDA, a mutated form of the proapoptotic Bik, can be considered a promising strategy in the field of gene therapy; (i) PEtOx-DOPE nanoliposomes can serve as safe and effective gene delivery platforms; and (iii) targeting of prostate cancer cells in vitro and in vivo can be achieved by employing the PSMA-targeting peptide P563, even for cells with only moderate upregulation of PSMA on the cell surface. The gene discussed is FOLH1; the disease is prostate cancer.