Ph.D Thesis


Ph.D StudentNaama Toledano Furman
SubjectDevelopment of Primary Cells Derived Vesicles Based Drug
Delivery System Platform for Targeted Cancer
Therapy
DepartmentDepartment of Biotechnology and Food Engineering
Supervisor Full Professors Machluf Marcelle


Abstract

The ultimate goal in cancer drug-delivery is a ‘magic-bullet’ that provides a versatile platform for site-specific targeting of multiple cancers, implemented in a clinically relevant and non-toxic design. Here, we present a novel drug-delivery system based on vesicles composed from the cytoplasmatic membranes of mesenchymal stem-cells (MSC), which are known for their natural targeting of multiple cancers and hypo-immunogenicity. Encompassing MSC surface proteins and armed with their unique targeting capabilities, the vesicles may be loaded with various drugs and as demonstrated in-vitro, can be selectively targeted against multiple cancers. We hypnotized that Nano-ghosts (NGs) produced from the membrane of MSCs could serve as tumor specific targeting vehicles for cancer therapy.

NGs preparations were shown to resemble common nano-scaled drug delivery systems in size, charge and morphology. The addition of the PEG to the NGs surface decreased the amount of available membrane proteins, still, the biological activity of the NGs remained.  In vitro evaluation of NGs ability to selectively interact with cancer cells showed clear preference for such interaction when compared to non- cancerous cell lines.  Bio-distribution in vivo assay showed accumulation of NGs at the tumors, 24 hrs and 1 week post IP administration.

In vivo immunogenicity study revealed that the nano-vesicles rapidly cleared from non-target organs, with neither apparent toxicities nor side effects. When comparing liver sections with un-treated mice using H&E analysis no pathological differences could be observed. Another Immunogenicity analysis showed that NG administration does not stimulate the immune system and that the levels of pro-inflammatory cytokines (e.g. TNF α, IL1β) resemble the levels of the mice control group.

A single systemic administration of sTRAIL (tumor necrosis factor related apoptosis inducing ligand) loaded vesicles, made from human or rat MSC, achieved local accumulation in the tumor site together with specific inhibition of human prostate tumor in nude mice demonstrating active inter-species in-vivo targeting. These results Imply towards the safety of this system and together with the promising results, the proof of concept of the CDV could be established.  In addition, such system may be readily modified to target various MSC-susceptible cancer tumors and other pathologies.