scientists: anti-malaria drug could treat breast cancer

U.S. scientists are studying the possibility of using an anti-malaria drug for the treatment of breast cancer patients whose disease has not responded to traditional chemotherapy treatment. Jenny Chang, director of the Methodist Cancer Center in Houston, is leading a study to look at the efficacy and safety of chloroquine, used in combination with chemotherapy, as a possible treatment for patients with advanced or metastatic breast cancer, according to the Texas Medical Center news issued Thursday. The combination of chloroquine and standard chemotherapy already has proven effective in mice with this disease, according to the report. Researchers from the Methodist Cancer Center and the Methodist Hospital Research Institute applied mathematical and bioinformatics models to screen for existing FDA-approved medications that might be effective against cancer stem cells, said Chang. "We identified chloroquine as a potential cancer stem- cell killer." The researchers are focusing on the response of chloroquine used in combination with Taxane or Taxane-like drugs. The active ingredient in these drugs blocks cell growth by stopping cell division, and helps prevent the progression of cancerous tumors. Cells typically maintain a constant pH level at all times. When chloroquine was introduced into mice with metastatic breast cancer, pH levels increased in certain components of the cells, enough to kill the cancer stem cells, the study shows. With limited funds flowing into new drug development, Chang said it is important to look at existing drugs to treat a variety of diseases. "We're very hopeful that this is a new paradigm that we can apply," said Chang. "By repurposing old drugs for 5 cents a day, we may make an impact by reversing treatment-resistance in women with breast cancer." U.S. physicians began using chloroquine in the late 1940s for the prevention and treatment of malaria. Chloroquine mildly suppresses the immune system, and it is used in some autoimmune disorders. Chloroquine is also being studied as a treatment in patients with relapsed multiple myeloma, pancreatic cancer, glioblastoma multiforme, and small-cell lung cancer.