Scientists have been able to synthesize
antibodies with the capability of disrupting proteins, like the
HER-2 receptor, which are found on the surfaces of some cancer cells. For example, the drug
Herceptin has been successful in treating breast tumors which "over express the HER-2 receptor" by targeting cancer cells for destruction. Designing antibody drugs to target other receptors on cancer-cell surfaces could potentially be successful in treating cancer; however, it is extremely difficult to get proteins inside the cells, making many cancer cells unreachable.
A team of MIT researchers has been evaluating
Bacillus anthracis, the bacteria which causes
anthrax, as a potential "deliverer" of antibodies to cancer cells.
Bacillus anthracis is of interest to the medical community as it is able to deliver large enzymes through the cell membrane, a feat rendered difficult to impossible in the administration of cancer drugs to specific cells.
The anthrax toxin kills cells through three mechanisms. The first is the
protective antigen (PA), a protein which binds to the TEM-8 and CMG-2 receptors found on most cells. Once PA binds to a cell, it creates a "docking site" for the two anthrax proteins called
lethal factor (LF) and
edema factor (EF). These proteins are sent into the cell and disrupt cellular processes, often causing cell death. However, if the sections responsible for the LF and EF proteins in anthrax are removed, the PA will leave channels that allow proteins to enter cells. This system can be used to deliver synthesized antibodies, referred to as antibody mimics, to cancer cells through the channels left by the PA to target specific proteins in cancer cells. The antibody mimics are smaller than antibodies and function to disrupt specific proteins within a cancer cell.
This article immediately caught my eye as I never would have expected the words "anthrax to deliver cancer drugs" to be put together. This article shows the importance of the combination of innovative and logical thinkers in medicine. If the MIT team is able to effectively replicate this method of administering antibodies to cancer cells in specific types of cells, this method may change oncology forever.
Article:
https://newsoffice.mit.edu/2014/cancer-drug-delivery-by-anthrax-0925
Related article:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3066103/