VANCOUVER, British Columbia, Feb. 21 (UPI) -- Blocking autophagy -- the process of "self-eating" within cells -- might be a viable way to enhance cancer treatment effectiveness, U.S. researchers said.
Dr. Ravi K. Amaravadi, an assistant professor at the Perelman School of Medicine and Abramson Cancer Center at the University of Pennsylvania, and his laboratory demonstrated adding hydroxychloroquine -- a Food and Drug Administration-approved drug used commonly for malaria and rheumatoid arthritis -- to many cancer therapies, including chemotherapy, targeted therapy, radiation and immunotherapy.
It can enhance the anti-tumor activity of these drugs in laboratory models of treatment-resistant cancers and ongoing clinical trials, Amaravadi said.
Autophagy is increased in cancer cells -- normally, it is a survival pathway allowing a cell to recycle damaged proteins when it's under stress and reuse the damaged parts to fuel further growth.
However, cancer cells might be addicted to autophagy, since this innate response may be a critical means by which the cells survive nutrient limitation and lack of oxygen commonly found within tumors. It might explain how some cancer cells evade chemotherapies, the study said.
Nearly 30 Phase I and Phase II clinical trials involving hydroxychloroquine have begun or are in the planning stages in many different malignancies, including melanoma, multiple myeloma, renal cell carcinoma, colon cancer, prostate cancer and breast cancer, Amaravadi said.
The findings were presented at the annual American Association for Advancement of Science meeting in Vancouver.