Bioengineered cells-derived vesicles as drug-delivery carriers for targeted cancer therapy

Abstract

Advances in genetic engineering tools have contributed to the development of strategies for utiliz-ing biologically derived vesicles as nanomedicines for achieving cell-specific drug delivery. Substantial efforts has been undertaken to understand the key attributes of natural drug carriers, such as physicochem-ical properties, drug loading efficiency, cancer targeting ability, cell entry mechanism, antigenic compo-nents and immunogenic potentials. Importantly, such engineered vesicles are utilized for delivery of vari-ous therapeutic payloads including small interfering RNA (siRNA) and chemotherapeutic agents. Here, I describe the natural drug delivery carriers derived from bioengineered bacteria or yeast cells, and demon-strated their utility in treating cancer. In chapter 2, I described bacterially derived nano-sized outer membrane vesicles (OMVs) as an ideal vector for encapsulation of therapeutic siRNA and cell specific delivery. I prepared OMVs from a bacterial strain, genetically engineered to have intrinsically low endotoxicity and over express cancer cell receptor specific high affinity protein (Affibody) on surface. Such engineered bio-vesicles were loaded with kinesin spindle protein (KSP) siRNA by employing simple electroporation protocol. The siRNA kinet-ics study assured receptor mediated OMV endocytosis, intracellular degradation and release of siRNA at therapeutically significant concentration. Consequently, significant inhibition of cell proliferation was ob-served. The OMVs I developed had reduced endotoxicity and immunogenicity to human cells. More im-portantly, due to their biological origin these nanoparticles are biodegradable and production scale up is easy. In chapter 3, I described yeast derived vacuoles as an ideal vector for chemotherapeutic agents. I prepared vacuoles from yeast strain which is genetically engineered to express cancer targeting ligand -affibody, on the surface of vacuoles. A simple mixing protocol was developed for...