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LAB TESTS SHOWS STRESS HORMONES TURN OVARIAN CANCER CELLS INTO INVADERS | |
| Contact: Anil Sood, MD Phone: 713-745-5266 Email: asood@mdanderson.org Embargoed until: March 4, 2004 |
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ORLANDO - STRESS HAS BEEN LINKED WITH CANCER PROGRESSION, BUT FOR THE FIRST TIME, RESEARCHERS HAVE DEMONSTRATED IN A LAB HOW "FIGHT OR FLIGHT" HORMONES MIGHT MAKE OVARIAN CANCER CELLS MORE INVASIVE. Researchers at the University of Texas M. D. Anderson Cancer Center have found that some of the hormones linked to behavioral stress - norepineophrine and epinephrine - can enhance the potential of ovarian cells to spread. "If we understand the biological pathway by which stress is linked to metastasis, then we can investigate how best to avoid those deleterious consequences," says the study's lead investigator, Anil Sood, M.D., an associate professor in the department of gynecologic oncology. "This study helps shed some light on those mechanisms." Sood is presenting the findings at the annual meeting of the American Psychosomatic Society. His collaborators include researchers from M. D. Anderson Cancer Center and the University of Iowa. When a person experiences excessive and persistent stress, the body reacts by releasing many hormones. Research has shown that these "stress" hormones can affect the immune system in cancer patients, and lead to cancer progression in some, but there has been little cell-based evidence for this link, as well as not much understanding as to why the connection exists at all. Sood and his collaborators found the first clue when he discovered that ovarian cells express high levels of "beta adrenergic" receptors that allow stress hormones to "dock" onto the cell, promoting a cascade of events inside the cell. Normal epithelial cells from the ovary have very few of the receptors. Theorizing the extra receptors must somehow help cancer cells survive and thrive, Sood has conducted a series of studies to test the effect of stress hormones on ovarian cell cultures. The researchers first demonstrated that stress hormones can directly result in elevated levels of a protein known as vascular endothelial growth factor (VEGF), which is important in cancer progression. Earlier, Sood and his colleagues had found that women with ovarian cancer who have greater distress and lack of social support tended to have higher levels of VEGF. In work published last fall, they discovered high levels of hormones prompted laboratory cancer cells to produce more VEGF. In the study now being reported, Sood and colleagues looked at the effect of the hormones on matrix metalloproteinases, (MMPs). These molecules are not only involved in angiogenesis, but in tumor growth, invasion, and the spread of cancer, and two of them, MMP-2 and MMP-9, have already been shown to play a significant role in ovarian cancer development and progression. MMPs can eat through bonds in the gel-like substance that holds cells in place, thus creating a path by which the cells can move away from the cell network and travel. The researchers exposed three different types of ovarian cancer cells, all derived from human tumors, to increasing levels of the different stress hormones. They found excess stress hormones produced high levels of both MMP-2 and MMP-9, thereby increasing the ability of the cancer cells to become invasive," says Sood. To check their results, the researchers then used drugs that inhibited actions of the stress hormones and found the cells stopped their progression. Sood says that some other cancer cell types, such as breast and colon, have also been found to over express receptors for stress hormones - although much of that work is in the beginning stages. "Cancer cells will do whatever works to their advantage. If stress hormones help promote growth and invasion, they will acquire those abilities," he says. The study was funded by the M. D. Anderson Cancer Center Ovarian Cancer SPORE and the Donna Marie Cimitile Fotheringham Award for Ovarian Cancer Research. | |
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Psychosomatic Medicine is the official peer-reviewed journal of the American Psychosomatic Society, published bimonthly. For information about the journal, contact Vicki White, Managing Editor for Manuscript Production,
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