The treatment of
cancer using macromolecular
therapeutics such as
oligonucleotides or
peptides requires efficient delivery systems capable of intracellular penetration and may also benefit from use of a combination of
therapeutics with different mechanisms of action. With this possibility in mind, we constructed cationic
liposome loaded with the proapoptotic
peptide, d-(KLAKLAK)(2) and the
Bcl-2 antisense oligodeoxynucleotide,
G3139, and determined whether the combination of the proapoptotic macromolecules in a single cationic
liposome can enhance antitumor efficacy. Advantage was taken of alternating charge interaction to entrap macromolecules of opposite charge. The polycationic
peptide d-(KLAKLAK)(2) was first condensed with the polyanionic
oligodeoxynucleotide G3139 to obtain overall negatively charged
peptide/
oligodeoxynucleotide complexes. The complexes were then entrapped into
DOTAP/DOPE cationic
liposomes (CL). This sequential charge interaction ensured efficient entrapment of d-(KLAKLAK)(2) and
G3139 with a high loading efficiency (50%) and capacity (7.5 wt %). In vitro treatment of mouse
melanoma B16(F10) with CL loaded with d-(
KLAKLAK)(2)/
G3139 led to significantly enhanced antitumor efficacy, mediated by stimulated induction of apoptotic (
caspase 3/7) activity, when compared to CL loaded with
G3139 alone. Intratumoral injection of CL loaded with d-(
KLAKLAK)(2)/
G3139 in B16(F10) mice xenograft also led to suppressed
tumor growth associated with enhanced apoptotic activity. Thus, the combination of proapoptotic
peptide d-(KLAKLAK)(2) and
antisense oligonucleotide G3139 in a cationic
liposome led to enhanced apoptotic/antitumor efficacy and may provide a promising tool for
cancer treatment.