Zosia Chustecka
Jan 11, 2013
A new hypothesis that focuses on reactive oxygen species (ROS) proposes that antioxidant levels within cancer cells are a problem and are responsible for resistance to treatment.
The theory destroys any reason for taking antioxidative nutritional supplements, because they “more likely cause than prevent cancer,” according to Nobel laureate James Watson, PhD, from Cold Spring Harbor Laboratory, New York.
Dr. Watson, who shared the Nobel prize for unraveling the structure of DNA, regards this theory as being “among my most important work since the double helix,” notes a press release from his institution, where he has been director since 1968.
The theory was published online January 8 in Open Biology.
Dr. Watson explains that the vast majority of agents used to directly kill cancer cells, including ionizing radiation, most chemotherapeutic agents, and some targeted therapies, work by generating — either directly or indirectly — ROS that block key steps in the cell cycle.
This generation of ROS creates a hypoxic environment in which cancers cells undergo a transformation from epithelial to mesenchymal cells (EMT).
These transformed cells almost inevitably posses very high amounts of antioxidants, which effectively block the effects of anticancer treatments, Dr. Watson notes. Once a cancer becomes resistant to chemotherapy, it usually is equally resistant to ionizing radiation, he points out.
In addition, these transformed EMT cancer cells generate free-floating mesenchymal cells, which have the flexibility and movement that allows them to metastasize to other body locations (brain, liver, lung). “Only when they have moved do most cancers become life-threatening,” Dr. Watson notes.
Interestingly, the widely used antidiabetic drug metformin has been shown to preferentially kill mesenchymal stem cells. “In a still much unappreciated article published 3 years ago,” metformin added to chemotherapy “induced prolonged remission if not real cures” in mouse models of cancer (Cancer Res. 2009;69:7507-7511), Dr. Watson writes. He notes that clinical trials are currently looking to see if adding metformin to chemotherapy provides clinical benefits, but adds that diabetics who have been using metformin regularly have a reduced incidence of many cancers.
..
.
.
Visit our MS Learning Channel on YouTube: http://www.youtube.com/msviewsandnews