SAN FRANCISCO, March 21 (Xinhua) -- Researchers have found that sulforaphane, a dietary compound from broccoli that's known to help prevent prostate cancer, may work through its influence on long, non-coding RNAs, or lncRNAs.
Among findings published in the Journal of Nutritional Biochemistry, researchers from Oregon State University (OSU) reported extra evidence for how these lncRNAs, once thought to be a type of "junk DNA" of no particular value or function, may instead play a critical role in triggering cells to become malignant and spread.
Growing evidence shows that lncRNAs, which number in the thousands and are highly cell-and tissue-specific, have a major role in cell biology and development, often by controlling what genes are turned on, or "expressed" to carry out their genetic function. Scientists now believe that when these lncRNAs are dysregulated, they can contribute to multiple disease processes, including cancer.
Unlike many chemotherapeutic drugs that affect healthy cells as well as malignant ones and can cause undesired side effects, the control of lncRNAs may offer a new way to specifically prevent or slow the progression of malignant cells.
The OSU research showed that one lncRNA, called LINC01116, is upregulated in a human cell line of prostate cancer, but can be decreased by treatment with sulforaphane.
The data "reinforce the idea that lncRNAs are an exciting new avenue for chemoprevention research, and chemicals derived from diet can alter their expression," the researchers wrote in their study.
"We showed that treatment with sulforaphane could normalize the levels of this lncRNA," Laura Beaver, a research associate in the Linus Pauling Institute and College of Public Health and Human Sciences and lead author on the study, was quoted as saying in a news release. "This may relate to more than just cancer prevention. It would be of significant value if we could develop methods to greatly slow the progress of cancer, help keep it from becoming invasive."
The researchers identified a four-fold decrease in the ability of prostate cancer cells to form colonies when LINC01116 was disrupted.
Among men, prostate cancer is the second most frequently diagnosed cancer globally and the second leading cause of cancer-related deaths in the United States.
Worth noting, the researchers said, is that an increased consumption of cruciferous vegetables such as broccoli appears to be associated with a lower risk of developing prostate cancer.
That same lncRNA, they noted, is also overexpressed in studies of several other types of cancer, including brain, lung and colon cancer. Some other lncRNAs have been found at higher levels in breast, stomach, lung, prostate cancer and chronic lymphocytic leukemia.
"This could be a turning point in our understanding of how cancer may be triggered and spreads," said Emily Ho, the endowed director of the Moore Family Center for Whole Grain Foods, Nutrition and Preventive Health at OSU, a professor in the College of Public Health and Human Sciences and principal investigator with the Linus Pauling Institute. "It's obviously of interest that this dietary compound, found at some of its highest levels in broccoli, can affect lncRNAs. This could open the door to a whole range of new dietary strategies, foods or drugs that might play a role in cancer suppression or therapeutic control."