Biochemical Basis for Broccoli's Cancer-Fighting Ability Discovered

Scientists are reporting discovery of a potential biochemical basis for the apparent cancer-fighting ability of broccoli and its vegetable relatives. They discovered for the first time that specific substances in the vegetables appear to target and block a defective gene associated with cancer.

The report, which could lead to new strategies for preventing and treating cancer, was published online January 11, 2011, in the American Chemical Society's (ACS) Journal of Medicinal Chemistry. Fung-Lung Chung, PhD, a professor of oncology, Lombardi Cancer Center, Georgetown University Medical Center (Washington DC, USA) and colleagues revealed in earlier research that compounds called isothiocyanates (ITCs)--found in broccoli, cauliflower, watercress, and other cruciferous vegetables--appear to stop the growth of cancer. However, nobody knew precisely how these substances work, a key to developing improved strategies for fighting cancer in humans. The tumor-suppressor gene p53 appears to play a major role in keeping cells healthy and preventing them from beginning the abnormal growth that is a hallmark of cancer. When mutated, p53 does not offer that protection, and those mutations occur in half of all human cancers. ITCs might work by targeting this gene, the report suggested.

The investigators evaluated the effects of certain naturally occurring ITCs on a variety of cancer cells, including lung, breast, and colon cancer, with and without the defective tumor-suppressor gene. They found that ITCs are capable of removing the defective p53 protein but seemingly leave the normal one alone. Drugs based on natural or custom-engineered ITCs could improve the effectiveness of current cancer treatments or lead to new strategies for treating and preventing cancer.

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Georgetown University Medical Center