Arsenic Nanoparticle Fights Breast Cancer in Black Women
African-American women are 10 percent less likely to be diagnosed with breast cancer than non-Hispanic white women, they are 34 percent more likely to succumb to the disease. Black women also contract the disease at an earlier age. The likelihood of finding breast cancer in black women at age 33 is the same as in finding it in white women at age 40. This breakthrough could increase the longevity African American breast cancer survivors.
Black women in the lowest socioeconomic category were treated less frequently with surgery and had a lower five-year survival rate.
Researchers at Northwestern University combined a drug therapy, which is effective against blood cancers but not solid tumors, with nanotechnology and the end result was a combatant of a powerful type of breast cancer that is most common in young, African-American women.
This aggressive cancer, called triple negative breast cancer, cannot be treated by any sort of life-saving therapies or traditional chemotherapy. More often than not, women with triple negative breast cancer have a low chance of survival.
The drug therapy, arsenic trioxide, which is now commonly used by Western oncologists for certain types of leukemia, is not effective against solid tumors on its own because it is excreted too quickly after being injected into the bloodstream for it to work. The amount if arsenic trioxide injected into the body cannot be increased either, due to its toxicity.
But now, researchers have combined the arsenic trioxide with a nanoparticle called a nanobin, which travels undetected after entering the bloodstream until it reaches the tumor and “attacks” it directly. The nanobin contains nanoparticulate arsenic trioxide embedded within a liposome (a tiny, thick vessel), and is cloaked in a chemical that both extends the nanobin’s life and prohibits other cells from seeing it as it passes through the bloodstream. In addition, exposure of the toxic drug to normal normal tissue as it moves through the bloodstream is limited, and when the nanobin reaches the blood vessel of the tumor, the arsenic nanoparticles are released and buried in the abnormal cells of the tumor.
Richard Ahn, a student in the medical scientists training program at Northwestern, along with Vince Cryns, associate professor of medicine and an endocrinologist at Northwestern Medicine, and Tom O’Halloran, director of the Chemistry of Life Processes Institute at Northwestern, have all authored a research paper on the nanobin, which was published in Clinical Cancer Research on July 15.
The nanobin was first tested on mice that contained triple negative breast cancer tumors. Some mice received the nanobin while others received regular arsenic trioxide therapy. The nanobin proved to decrease tumor growth while arsenic trioxide alone was not effective at all.
“The anti-tumor effects of the arsenic nanobins against clinically aggressive triple negative breast tumors in mice are extremely encouraging,” said Cryns. “There’s an urgent need to develop new therapies for poor prognosis triple negative breast cancer.”
The development of this arsenic nanoparticle has opened the door to many other opportunities, such as making other existing cancer drugs, which have been set to the side due to their level of toxicity or because they’re excreted too quickly, more effective in cancer tumor treatment. Researchers are now looking to improve the nanotechnology associated with cancer treatment by “decorating the nanobins with antibodies that recognize markers on tumor cells to increase the drug’s uptake by the tumor.” They’d also like to find a way to deliver two drugs within the same liposome to the tumor.
“Everyone said you can’t use arsenic for solid tumors,” saidO’Halloran. “That’s because they didn’t deliver it the right way. This new technology delivered the drug directly to the tumor, maintained its stability and shielded normal cells from the toxicity. That’s huge.”