Arsenic nanoparticle holds promise in blocking aggressive breast cancer

Abstract

Researchers at Northwestern University in Evanston, Illinois have discovered that a drug therapy previously found to be ineffective against solid tumors could help combat an aggressive type of breast cancer that is common in young women, particularly those who are black.1 When packaged with nanotechnology, the drug—arsenic trioxide—proved effective in combating triple-negative breast cancer, which does not respond well to traditional chemotherapy. The disease has a high rate of metastasis and poor survival rates. Arsenic trioxide has long been used in ancient Chinese medicine and was recently used by Western physicians to treat a type of leukemia. In the past, arsenic was excreted too rapidly to be effective in solid tumors and the dose could not be increased because it was too toxic. However, researchers designed a new arsenic nanoparticle called nanobin that slips undetected through the bloodstream until it arrives at the tumor. When injected in mice, the nanobins reduced tumor growth. The research indicates that nanoparticle technology has potential for other existing cancer drugs that have been rejected for being too toxic or excreted too rapidly. “We can potentially make those drugs more effective against solid tumors by increasing their delivery to the tunior and by shielding normal cells from toxicity,” says senior author Vince Cryns, MD, an endocrinologist at Northwestern University. The nanobin is comprised of a nanoparticulate arsenic trioxide encapsulated in a liposome and coated with a second layer of a cloaking chemical that prolongs the life of the nanobin and keeps scavenger cells from detecting it. When it becomes absorbed by the abnormal blood cells of the tumor, the nanoparticles of arsenic are released and trapped in the tumor cells. Researchers are working to further refine and improve the technology, including decorating the nanobins with antibodies that recognize markers on the tumor cells to increase the drug's uptake by the tumor and putting 2 or more drugs into the same nanobin to deliver them together.