Liposomes-mediated delivery of pro-apoptotic therapeutic membrane proteins.

The delivery of functional therapeutic proteins by lipid vesicles into targeted living cells is one of the most promising strategies for treatment of different diseases and cancer. The use of this system in the delivery of membrane proteins directly into cells remains to be tested because the methods for producing membrane proteins are difficult to perform. Here we describe the effect of proteoliposomes containing the voltage-dependent anion channel (VDAC) and pro-apoptotic Bak, both produced with an optimized cell-free expression system. For the first time, recombinant VDAC and Bak proteins are synthesized and directly integrated into the lipidic bilayer of natural liposomes in a one-step reaction. VDAC has been shown to play an essential role in apoptosis in mammalian cells by regulating cytochrome c release from mitochondria and Bak modulates mitochondrial membrane permeability upon activation. Internalization of recombinant proteoliposomes into mammalian cells induces apoptosis by release of cytochrome c and caspases activation. These results highlight that membrane proteins integrated in natural liposomes can represent an excellent candidate for cancer protein therapy.