According to the co-authored paper published by ARCS scholar Daniel Elson, despite new cancer therapeutics that are discovered at a rapid pace, lack of effective means of delivery thwart many promising therapeutics. Cancer treatment is often accompanied by unacceptable side-effects such as that seen in chemotherapy. These adverse effects result from the action of drugs on healthy tissues, beyond just the target tumor site, and also result from drugs affecting molecular targets that are present in normal and cancerous tissues.

Two principles that are used to overcome these obstacles include targeting molecular aberrations that are present in cancer cells and not healthy cells, which can be difficult to identify; and the second principle being selective delivery of a drug to only the target tumor site, so that only the cancer cells are exposed and not healthy tissues. 

Daniel Elson's paper describes a combination of these two approaches. "Our drug NuBCP9 targets a protein called Bcl-2 that is present in very high levels in chemo-resistant tumor cells (particularly breast cancers and lung cancers), but present at low levels in normal cells. Bcl-2 normally functions to shield cells from death and promotes cancer cell survival, however our drug is capable of switching Bcl-2 from a pro-survivor protein to a pro-death protein, effectively flipping the scales on cancer cells." 

The second novelty of this work is the use of hollow gold nanoparticles to package our drug and promote specific activation at only the cancer site. Packaging of the drug into gold nanoparticles increases the stability of the drug and increases the amount of drug capable of entering the tumor cell. Importantly, the drug is only released upon exposing the nanoparticle to a specific wavelength of light. 

Thus, in practice, these nanoparticles with drug packaged in them can be delivered to a cancer patient, and the clinician can selectively activate the drug only at the tumor site and circumvent the adverse effects of chemotherapy and non-specific drug delivery. 

Improved in Vivo Targeting of BCL-2 Phenotypic Conversion through Hollow Gold Nanoshell Delivery