nanotimes News in Brief
10-09 :: September 2010
Cancer Medicine // New Technology Targets Cancer Prevalent in Young Women
orthwestern University researchers took a drug therapy proven for blood cancers but ineffec-
tive against solid tumors, packaged it with nanotech- nology and got it to combat an aggressive type of breast cancer prevalent in young women, particu- larly young African-American women.
That drug is arsenic trioxide, long part of the arsenal of ancient Chinese medicine and recently adopted by Western oncologists for a type of leukemia. The cancer is triple negative breast cancer, which often doesn‘t respond well to traditional chemotherapy and can‘t be treated by potentially life-saving tar- geted therapies. Women with triple negative breast cancer have a high risk of the cancer metastasizing and poor survival rates.
Prior to the new research, arsenic hadn‘t been effec- tive in solid tumors. After the drug was injected into the bloodstream, it was excreted too rapidly to work. The concentration of arsenic couldn‘t be increased, because it was then too toxic.
A new arsenic nanoparticle – designed to slip un- detected through the bloodstream until it arrives at the tumor and delivers its poisonous cargo – solved all that. The nanoparticle, called a nanobin, was injected into mice with triple negative breast tumors. Nanobins loaded with arsenic reduced tumor growth in mice, while the non-encapsulated arsenic had no
effect on tumor growth. The arsenic nanobins blo- cked tumor growth by causing the cancer cells to die by a process known as apoptosis.
The nanobin consists of nanoparticulate arsenic trioxide encapsulated in a tiny fat vessel (a lipo- some) and coated with a second layer of a cloaking chemical that prolongs the life of the nanobin and prevents scavenger cells from seeing it. The nanobin technology limits the exposure of normal tissue to the toxic drug as it passes through the bloodstream. When the nanobin gets absorbed by the abnormal, leaky blood vessels of the tumor, the nanoparticles of arsenic are released and trapped inside the tumor cells.
“The anti-tumor effects of the arsenic nanobins against clinically aggressive triple negative breast tumors in mice are extremely encouraging,” said Vince Cryns, associate professor of medicine and an endocrinologist at Northwestern Medicine and a member of the Robert H. Lurie Comprehensive Cancer Center of Northwestern University.
Cryns and Tom O‘Halloran, director of the Chemi- stry of Life Processes Institute at Northwestern, are senior authors of a paper on the research. Richard Ahn, a student in the medical scientists training pro- gram at Northwestern, is lead author.