We are constantly bombarded by messages telling us that certain foods will prevent cancer or will give us cancer. Some foods even appear to reportedly do both, depending who you listen to or what you read, making it difficult to make informed dietary choices.
However, broccoli and other similar vegetables are well-accepted to likely reduce the risk of several cancers and today a new study led by researchers at Harvard Medical School and published in Science, one of the world’s most prestigious scientific journals, has suggested that a particular compound found in the vegetable may have potential in both preventing and possibly treating certain types of cancer.
“We found a new important player that drives a pathway critical to the development of cancer, an enzyme that can be inhibited with a natural compound found in broccoli and other cruciferous vegetables,” said Pier Paolo Pandolfi, MD, PhD, Director of the Cancer Center and Cancer Research Institute at Beth Israel Deaconess Medical Center, Harvard Medical School in Boston.
Many cancers exhibit inactivated or low levels of proteins called tumor suppressors. These tumor suppressors do exactly what their name suggests. When switched on, they stop or limit the ability of cancers to form. When inactivated for any reason, they render a cell more susceptible to becoming cancerous.
One of the most important tumor suppressors is a protein called PTEN. Many human cancers are known to exhibit low levels of PTEN and Pandolfi and colleagues wanted to find out if there was anyway to restore PTEN’s protective function. They found another protein called WWP1, an enzyme that stops PTEN from functioning properly and sought to see if there was anything they could do to stop WWP1.
When searching for compounds which could disable WWP1, they discovered indole-3-carbinol (I3C), found in broccoli and other similar vegetables such as cauliflower, kale, collard greens and brussels sprouts. The team gave this compound to mice genetically engineered to be predisposed to cancer and found that it was able to restore PTEN’s cancer surpressive power by stopping WWP1 from working.
“This pathway emerges not only as a regulator for tumor growth control, but also as an Achilles’ heel we can target with therapeutic options,” said Pandolfi.
I3C has only been tested in mice so far. However, the researchers are excited about the potential of their findings and they hope that this discovery can eventually be used to figure out how to turn PTEN back on in cancer cells which have lost function. However, even if the results for mice ring true with humans, to get an equivalent dose of I3C you would have to eat six pounds of raw broccoli daily. You do not have to be a dietitian to know that this will likely come with a host of unpleasant digestive side effects.
The researchers are looking for less drastic solutions to build upon the knowledge that broccoli has given them and have some ideas, including synthesizing I3C or a similar molecule in a lab or using other approaches to inactivate WWP1.
“Either genetic or pharmacological inactivation of WWP1 with either CRISPR technology or I3C could restore PTEN function and further unleash its tumor surpressive activity.These findings pave the way toward a long-sought tumor suppressor reactivation approach to cancer treatment,” said Pandolfi.