Luteolin, a natural compound found in herbs such as thyme and parsley and in vegetables such as celery and broccoli, may reduce the cancer risk for women who have taken hormone replacement therapy.
More than 100 women die from breast cancer every day in the United States. The odds increase in postmenopausal women who have taken a combined estrogen and progestin hormone replacement therapy—and these women also have an increased risk of developing progestin-accelerated breast tumors.
“In most circumstances, hormone replacement therapies improve the lives of menopausal women and achieve excellent results,” said Salman Hyder, professor in tumor angiogenesis and professor of biomedical sciences at University of Missouri.
“Nevertheless, research has proven that a higher incidence of breast cancer tumors can occur in women receiving therapies that involve a combination of the natural component estrogen and the synthetic progestin.
“Most older women normally have benign lesions in breast tissue,” Hyder said. “These lesions typically don’t form tumors until they receive the ‘trigger’—in this case, progestin—that attracts blood vessels to cells essentially feeding the lesions causing them to expand.”
The study, published in August in the journal Springer Plus, shows that when the supplement luteolin is administered to human breast cancer cells in the lab, vessels “feeding” the cancer cells causing cancer cell death are reduced.
As human breast cancer cells develop, they tend to take on stem-cell-like properties, which can make them harder to kill. Here, luteolin was used to monitor stem-cell-like characteristics of breast cancer cells and researchers saw a vast reduction in this phenomenon, further proving that the natural compound exerts its anti-tumor effects in a variety of ways.
Then, researchers further tested laboratory mice with breast cancer and found that blood vessel formation and stem-cell-like characteristics also were reduced in vivo, or inside the body.
“We feel that luteolin can be effective when injected directly into the bloodstream, so IV supplements may still be a possibility,” Hyder said. “But, until the supplement is tested for safety and commercialized, which we hope will happen after further testing and clinical trials, women should continue consuming a healthy diet with fresh fruits and vegetables.”
The early-stage results are promising. If additional studies are successful within the next few years, researchers will request authority from the federal government to begin human drug development (this is commonly referred to as the “investigative new drug” status).
After this status has been granted, researchers may conduct human clinical trials with the hope of developing new treatments for breast cancer in women who have taken combined estrogen and progestin hormone replacement therapies.
Donations to the Ellis Fischel Cancer Center at the University of Missouri funded the work.