An anti-cancer compound found in broccoli and cabbage lowers the activity of an enzyme associated with rapidly advancing breast cancer, according to a study at the University of California.
The compound, indole-3-carbinol, is already undergoing clinical trials in humans after it was found to halt the growth of breast cancer and prostate cancer cells in mice.
“This is a major breakthrough in trying to understand what the specific targets of these natural products are,” said coauthor Leonard Bjeldanes, UC Berkeley professor of toxicology.
“The field is awash with different results in various cells, but no real identification of a specific molecular target for these substances. The beauty of identifying the target like this is that it suggests further studies that could augment the activity of this type of molecule and really specify uses for specific cancers.”
The researchers showed that I3C inhibits the enzyme elastase, which is an enzyme that shortens a cellular chemical, cyclin E, that is involved in controlling the cell cycle. The shortened version of cyclin E accelerates the cell cycle, making cancer cells proliferate faster. The study showed that I3C prevents the elastase shortening of cyclin E, thereby arresting development of breast cancer cells.
Though the anti-cancer benefits of vegetables in the cabbage family have been recognized since the 1970s, the mechanism is only now being discovered, and the findings from this study are the first to explain how indole-3-carbinol (I3C) stops cancer cell growth.
In previous work, the researchers found that indole-3-carbinol interferes with more than cell proliferation. It also disrupts the migration and alters adhesion properties of cancer cells, as well as counteracts the survival ability of cancer cells, all of which are implicated in cancer cell growth. To have such broad downstream effects, I3C must act at the beginning of a major cellular pathway, Firestone said. The newly reported research pins this activity to elastase and its effect on cyclin E.
I3C is available as a supplement and is a preferred preventative treatment for recurrent respiratory papillomatosis, a condition involving non-malignant tumors of the larynx.