Eating vegetables like cauliflower and cabbage are known to prevent breast cancer. But the mechanism by which the active substances in these vegetables inhibit cancer cell proliferation was unknown – until now.Leslie Wilson, professor of biochemistry at the University of California Santa Barbara (UCSB) and Mary Ann Jordan, adjunct professor in molecular, cellular and developmental biology, have shown how the healing power of these vegetables works at the cellular level.
“Breast cancer, the second leading cause of cancer deaths in women, can be protected against by eating cruciferous vegetables such as cabbage and near relatives of cabbage such as broccoli and cauliflower,” said co-author Olga Azarenko, a graduate student at UCSB.
“These vegetables contain compounds called isothiocyanates which we believe to be responsible for the cancer-preventive and anti-carcinogenic activities in these vegetables. Broccoli and broccoli sprouts have the highest amount of the isothiocyanates.
“Our paper focuses on the anti-cancer activity of one of these compounds, called sulforaphane, or SFN,” Azarenko added. “It has already been shown to reduce the incidence and rate of chemically induced mammary tumours in animals. It inhibits the growth of cultured human breast cancer cells, leading to cell death.”
The paper was published in this month’s journal Carcinogenesis.
Azarenko made the surprising discovery that SFN inhibits the proliferation of human tumour cells by a mechanism similar to the way that the anti-cancer drugs taxol and vincristine inhibit cell division during mitosis.
Mitosis is the process in which the duplicated DNA in the form of chromosomes is accurately distributed to the two daughter cells when a cell divides, said an UCSB statement.
“SFN may be an effective cancer preventive agent because it inhibits the proliferation and kills precancerous cells,” said Wilson. It is also possible that it could be used as an addition to taxol and other similar drugs to increase effective killing of tumour cells without increased toxicity.