Eli Lilly's Osteoporosis Drug Raloxifene May Also Treat Cancers
Researchers from the Oregon State University (OSU) found that Raloxifene, used in the treatment of osteoporosis in post-menopausal women, may also be effective against some types of liver and breast cancers. Raloxifene is currently marketed under the brand name Evista by Eli Lilly and Co. The U.S. Food and Drug Administration (FDA) first approved the drug for bone loss prevention in post-menopausal women in 1997. Two years later, the drug was approved for treatment of postmenopausal women with osteoporosis. In 2007, raloxifene was approved for reducing risk of invasive breast cancer in post-menopausal women with osteoporosis as well as in post-menopausal women at high risk for invasive breast cancer. Raloxifene is known to block estrogen from binding to its receptors and therefore inhibits breast cancer cell multiplication.
OSU researchers found that the drug targeted and killed human “triple-negative” breast cancer cells and liver cancer cells. Triple-negative breast cancer accounts for about 15-20% of all breast cancer cases in the U.S. and occurs more frequently in younger and African-American women. Triple-negative breast cancer does not respond to typical treatments such as tamoxifen or trastuzumab due to lack of estrogen receptors.
The drug was observed to bind with the aryl hydrocarbon receptor (AhR) protein and kill cancer cells which lack receptors for estrogen. Ed O’Donnell, a postdoctoral scholar at OSU who conducted the research, found an increased survival rate in women with breast cancer who had higher levels of the AhR protein.
Siva Kolluri, OSU cancer researcher who led the research, said, “Our findings are exciting for two reasons. No. 1, our research revealed that we can target a specific protein, the AhR, to potentially develop new drugs for liver cancer and a subset of stubborn breast cancers. That's a major goal of our lab. No. 2, we discovered that raloxifene, a known drug, could potentially be repurposed to treat two distinct types of cancers.”
No clinical trials have yet been conducted to evaluate raloxifene’s safety and efficacy in treatment of breast and/or liver cancer.
The OSU research article “The Aryl Hydrocarbon Receptor Mediates Raloxifene-induced Apoptosis in Estrogen Receptor Negative Hepatoma and Breast Cancer Cells” was published in the journal Cell Death and Disease and was funded by the American Cancer Society, the U.S. Department of Defense Breast Cancer Research Program, and the National Institute of Environmental Health Sciences.