Team:Penn/ProjectResults

What if you could combine spatial targeting and cellular targeting into the same therapeutic? This idea is unprecedented but would allow for precise targeting of specific cells within a specific area, leaving healthy tissue intact and keeping side effects to a minimum. Higher dose precision means more of the therapeutic would be used efficiently in the targeted area and the dependency on passive diffusion – and the uncertainties that comes with it – would be eliminated.

The 2012 Penn iGEM team has engineered a novel, modular platform for targeted therapeutics that employs simultaneous spatial and cellular targeting. We have achieved spatial (and temporal) targeting with a blue light-switchable transgene expression system and cellular targeting through display of an antibody-mimetic protein on the surface of E. coli for the first time. Our platform also enables more precise dose control in the targeted area through the length of blue-light exposure, which allows us to regulate effective levels of transgene expression.

As a proof of concept, we applied our system to the treatment of cancer, a disease in which spatial and cellular targeting are of utmost importance. We displayed a high-affinity antibody-mimetic protein that targets Human Epidermal Growth Factor Receptor 2 (HER2), a protein commonly overexpressed in cancer cells, especially in breast cancer tumors. We combined this cellular targeting with a light-activated cytotoxic protein delivery system to successfully target and kill breast cancer cells.

The strength in our platform lies in its modularity. Both the light-induced transgene expression system and the surface display system work and exist independently of each other on two compatible plasmids. These plasmids can be modified to meet the needs of any synthetic biologist.

Any gene of interest can be cloned into the light-induced transgene expression system and will then be expressed in a light-dependent and spatially controlled manner. Any targeting protein can be cloned into our surface display platform to allow cellular targeting against any desired biomarker. These modular plasmids may then be co-transformed together to create a bacterial therapeutic for a desired disease.

These modular components could also be extended into applications other than medical therapeutics, such as biocatalysis, manufacturing, and alternative energy.

Spatial Targeting: Surgeons excise a tumor manually, without regard for cellular heterogeneity within and around the tumor area.	Cellular Targeting: Monoclonal antibodies identify antigens on certain cells or viruses. Monoclonal antibodies are often coupled with therapeutic agents. However, if the antigen is present in healthy tissue outside the diseased area, it will be targeted as well.