Anthrax May Deliver Cancer Drugs with Efficient Injection Method

Anthrax, also known as Bacillus anthracis bacteria, have a very efficient method when it comes to injecting toxic proteins into cells. Now, scientists are recruiting anthrax and its delivery system in order to administer cancer drugs.

"Anthrax toxin is a professional at delivering large enzymes into cells," said Bradley Pentelute, one of the researchers, in a news release. "We wondered if we could render anthrax toxin nontoxic, and use it as a platform to deliver antibody drugs into cells."

Antibodies are natural proteins that the body produces to bind to foreign invaders. Inspired by natural-occurring antibodies, scientists have designed new antibodies that can disrupt proteins found on the surfaces of some cancer cells, such as the HER2 receptor. While several antibody drugs have been developed to target other receptors, though, the potential usefulness has been limited since it's difficult to get proteins inside cells.

That's why scientists turned to anthrax. The anthrax toxin has three major components. One is a protein called protective antigen (PA) which binds to receptors called TEM8 and CMG2 that are found on most mammalian cells. Then once PA attaches to the cell, it forms a docking site for two anthrax proteins called lethal factor (LF) and edema factor (EF). These proteins are bumped into the cell through a narrow pore and disrupt cellular processes.

In this case, the scientists removed sections of the LF and EF proteins and left behind the sections that allowed the proteins to penetrate cells. Then, they replaced the toxic region with antibody mimics.

"This work represents a prominent advance in the drug-deliver field," said Jennifer Cochran, one of the researchers, "Given the efficient protein delivery Pentelute and colleagues achieved with this technology compared to a traditional cell-penetrating peptide, studies to translate these findings to in vivo disease models will be highly anticipated."

The findings are published in the journal ChemBioChem.