DUARTE, Calif., October 6, 2008 — City of Hope has received a three-year, $600,000 grant from Susan G. Komen for the Cure™ to support research in reducing side effects and preventing drug resistance during treatment of hormone-dependent breast cancer. City of Hope researchers are studying the combination therapy of aromatase inhibitors, which block the production of estrogen, and an investigational drug that specifically targets breast cancer cells.
This year in the U.S., an estimated 182,460 women will be diagnosed with breast cancer, according to the American Cancer Society. A major focus of the breast cancer research conducted at City of Hope centers on the role of aromatase, an enzyme that converts the male hormone androgen into estrogen. Shiuan Chen, Ph.D., principal investigator, and co-leader of the Breast Cancer Research Program, studies the regulatory mechanism of aromatase expression in breast cancer cells. His lab was one of three internationally to discover that breast cancer cells produce their own estrogen.
Approximately 70 percent of breast cancers are hormone dependent, requiring estrogen to survive and grow. Hormone-dependent breast cancers are sensitive to estrogen levels, and can be treated with drugs that block or control estrogen levels in the body. “Aromatase inhibitors (AI) are a type of breast cancer drug that work by drastically lowering estrogen levels in the body,” said Chen, director of the Division of Tumor Cell Biology, Beckman Research Institute at City of Hope.
Aromatase inhibitors are effective in eradicating cancer, particularly in postmenopausal patients, yet they produce debilitating side effects – from severe joint pain to bone loss and fractures. Another drawback is that patients who receive long-term treatment with aromatase inhibitors can develop resistance to them.
Chen’s previous research concluded that an investigational drug, LBH589, is a potent inhibitor of aromatase expression in breast cancer cells, but does not affect healthy cells. The combined use of LBH589 and aromatase inhibitors such as letrozole may help prevent the side effects and drug resistance in the treatment of hormone-dependent breast cancer in postmenopausal women. The combination therapy can potentially lower the dose of aromatase inhibitor a patient needs, which may reduce side effects, and delay drug resistance.
“The Susan G. Komen for the Cure grant will help us understand how LBH589 works and explore whether a combination of typical aromatase inhibitors with this drug will produce a synergistic effect,” said Chen.
The drug may work in an epigenetic manner by turning select genes on or off, and Chen wants to identify those switches. Preclinical trials on the combination therapy also are aimed at understanding the effectiveness of combination therapy in stopping estrogen production in breast cancer cells and in delaying resistance.
LBH589 is particularly promising because it already has been approved by the Food and Drug Administration for use in leukemia patients. If it proves effective during the current preclinical trials, it eventually could be adapted more quickly for use in breast cancer patients.
About Susan G. Komen for the Cure
Nancy G. Brinker promised her dying sister, Susan G. Komen, she would do everything in her power to end breast cancer forever. In 1982, that promise became Susan G. Komen for the Cure and launched the global breast cancer movement. Today, Komen for the Cure is the world’s largest grassroots network of breast cancer survivors and activists fighting to save lives, empower people, ensure quality care for all and energize science to find the cures. Thanks to events like the Komen Race for the Cure, we have invested more than $1 billion to fulfill our promise, becoming the largest source of nonprofit funds dedicated to the fight against cancer in the world. For more information about Susan G. Komen for the Cure, breast health or breast cancer, visit www.komen.org or call 1-877-GO KOMEN.