Furthermore, from a therapeutic standpoint, we establish the ability of these engineered EVs to efficiently and specifically deliver either a bifunctional apoptotic peptide targeted to CXCR4 to suppress leukemia, or an antisense oligonucleotide (ASO) to knockdown oncogenic miR-125b in EGFR-expressing breast cancer cells, resulting in decreased cell viability in both cases. The gene discussed is CXCR4; the disease is leukemia.