Chemotherapy: From chemical warfare to nanotech assassins

July 16, 2010

Some intriguing news out of Northwestern yesterday: Researchers have taken a poison -- arsenic -- worked some nanotech mojo on it, and come up with a chemotherapy treatment that seems to be effective in treating an aggressive form of breast cancer. At least, in mice. This got me thinking about chemotherapy, that signature cancer treatment, and how it has evolved. Chemotherapy is not pleasant. A breast cancer survivor named Eloise Orr told me chemo was the worst experience of her life -- this from a person who had holes drilled in her skull for multiple brain surgeries. Chemo, after all, is poison -- based on a concept from a more primitive era of medicine, and unchanged in some ways for about 60 years. Chemo has its origins in chemical warfare -- a fact that may not surprise people who have been subjected to its agonies. During World War II, an American ship called the John Harvey was docked off of Bari, Italy, when the Germans bombed the harbor. The John Harvey exploded, along with about 100 tons of mustard gas weapons on board. Dozens died, but among the survivors doctors noticed a peculiar phenomenon -- they seemed to have weirdly low white blood cell counts. That was the first clue that poison could be directed at certain kinds of disease cells, and it would develop into early treatment tests for lymphoma. Since then, the poisons have gotten more sophisticated, but they're still poisons. Philip Bonomi, director of oncology and hematology at Rush University Medical Center, says chemo drugs attack either a tumor cell's DNA, or little structures that form a cell's skeleton. The trouble, of course, is that they also hit healthy cells -- especially fast-dividing ones like nerve, cheek and hair follicle. By fine-tuning the doses and adding other medicines, doctors are able to blunt some of the worst side effects. Northwestern's nanotech solution is an example of innovating the way the drug is delivered. They cooked up a nano-sized particle of arsenic called a nanobin that goes right for the tumor -- in this case, a "triple-negative" breast cancer, which is especially deadly and affects many young black women. Dr. Bonomi told me about another new delivery method -- essentially a heat-seeking missile. A chemotherapy molecule stows away on an antibody, which by nature only seeks this one particular protein that lives on breast cancer cells. So the antibody makes a beeline for the tumor, at which point the stowaway assassin hops off and whacks the cancer. CHEMO AUDIO 1 For more than six decades, scientists have been trying to figure out how to poison the cancer while poisoning the patient as little as possible. On its face, getting even a "light poisoning" doesn't sound like the most comforting treatment paradigm. So now the push is developing targeted therapies that can distinguish between good cells and bad cells. I asked Bonomi if the chemotherapy model would always be with us in one form or another. To my mild surprise, he said he has no doubt that chemo -- a technology born of warfare -- won't be our weapon of choice much longer. Chemo Audio 2

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