 |
|
Jefferson researchers uncover new evidence of prolactin's possible role in breast cancer
October 01, 2007(PHILADELPHIA) Scientists at the Kimmel Cancer Center at Jefferson in Philadelphia have discovered new molecular evidence of the role of the hormone prolactin in breast cancer. They have found that prolactin, a pituitary hormone that normally stimulates breast development and milk production, initiates a new "signaling pathway" that may regulate the growth and survival of breast cancer cells.
The work, which appears this month in the journal Molecular Endocrinology, identifies the protein Jak1 as playing a key part in prolactin signaling in breast cancer. Jak1, which belongs to the cell growth-promoting tyrosine kinase class of enzymes, could represent a new drug target for treating breast cancer.
"In breast cancer cells, we found that Jak1 not only stimulates conventional prolactin signaling via proteins such as Stat5, but also that Jak1 recruited new signals, especially Stat3 and ERK," says Hallgeir Rui, M.D., Ph.D., professor of Cancer Biology at Jefferson Medical College of Thomas Jefferson University and principal investigator of the study. "Because Stat3 and ERK typically are considered tumor-promoting, inhibitors of Jak1 may become useful in breast cancer treatment."
Receptors for prolactin, have previously been shown to promote breast cancer cell growth, survival, and differentiation, Dr. Rui explains, through signaling pathways that involve activation of such proteins as Stat5, ERK, and Akt. Prolactin is also known toactivate Stat3, which has been implicated as an oncogene involved in cancer cell growth and survival. In the current study, when Jak1 protein expression was experimentally disrupted in breast cancer cells, prolactin signaling through Stat3 and ERK was completely blocked. Signaling through Stat5 and Akt was reduced but still present.
"Until now, prolactin was believed to signal only through Jak2 to mediate its effects," says Lynn Neilson, Ph.D., a postdoctoral fellow in the Department of Cancer Biology at Jefferson Medical College and first author of the study. "The unexpected finding that prolactin also activates Jak1 in breast cancer points to a mechanism in cancer cells that further promotes tumor cell growth."
Dr. Rui's laboratory currently is seeking to determine the role of Jak1 in breast cancer cell growth, survival, and invasion, which will be important for establishing the potential usefulness of Jak1 as a new drug target in patients. Prolactin is secreted by the pituitary gland, and important for milk production during lactation. Receptors for this hormone are present on a majority of breast cancers. Prolactin levels in blood are relatively unaffected by menopause, and breast cancer patients are exposed to the hormone across all age groups.
Thomas Jefferson University
Receptors for prolactin, have previously been shown to promote breast cancer cell growth, survival, and differentiation, Dr. Rui explains, through signaling pathways that involve activation of such proteins as Stat5, ERK, and Akt. Prolactin is also known toactivate Stat3, which has been implicated as an oncogene involved in cancer cell growth and survival. In the current study, when Jak1 protein expression was experimentally disrupted in breast cancer cells, prolactin signaling through Stat3 and ERK was completely blocked. Signaling through Stat5 and Akt was reduced but still present.
"Until now, prolactin was believed to signal only through Jak2 to mediate its effects," says Lynn Neilson, Ph.D., a postdoctoral fellow in the Department of Cancer Biology at Jefferson Medical College and first author of the study. "The unexpected finding that prolactin also activates Jak1 in breast cancer points to a mechanism in cancer cells that further promotes tumor cell growth."
Dr. Rui's laboratory currently is seeking to determine the role of Jak1 in breast cancer cell growth, survival, and invasion, which will be important for establishing the potential usefulness of Jak1 as a new drug target in patients. Prolactin is secreted by the pituitary gland, and important for milk production during lactation. Receptors for this hormone are present on a majority of breast cancers. Prolactin levels in blood are relatively unaffected by menopause, and breast cancer patients are exposed to the hormone across all age groups.
Thomas Jefferson University
Breast Cancer News and Current Breast Cancer Events RSSDuke chemists synthesize promising anti-cancer product
Duke University chemists have patented an efficient technique for synthesizing a marine algae extract in sufficient quantities to now test its ability to inhibit the growth of cancerous cells while leaving normal cells unaffected.
Slipping through cell walls, nanotubes deliver high-potency punch to cancer tumors in mice
The problem with using a shotgun to kill a housefly is that even if you get the pest, you'll likely do a lot of damage to your home in the process. Hence the value of the more surgical flyswatter.
Targeted radiation therapy can control limited cancer spread
Precisely targeted radiation therapy can eradicate all evidence of disease in selected patients with cancer that has spread to only a few sites, suggests the first published report from an ongoing clinical trial.
Risk assessment plays key role in long-term treatment of breast cancer
Breast cancer patients and their physicians may make more informed, long-term treatment decisions using risk assessment strategies to help determine probability of recurrence.
First step towards switching off breast cancer and leukaemia
Australian scientists have identified a way to 'switch off' a molecule, a key player in the molecular processes that trigger breast cancer and certain forms of leukaemia.
Exercise Pill is No Replacement for Exercise
Recently, researchers at the Salk Institute for Biological Studies, a research organization focused on biology and its relation to health, published a study in the journal Cell on the results of a substance that increased exercise endurance without daily exertion when tested in mice.
Perceived discrimination affects screening rates
Minority men and women who perceived discrimination from their health care providers were less likely to be screened for colorectal or breast cancer, according to a report in the August issue of Cancer Epidemiology, Biomarkers and Prevention, a journal of the American Association for Cancer Research.
Breast cancer confessions: The emotional work of disclosing a diagnosis
Women diagnosed with breast cancer shoulder the emotional burden of disclosing their diagnosis to loved ones, managing the feelings of others at precisely the time when they need support themselves, according to research to be presented at the annual meeting of the American Sociological Association (ASA).
Improved estrogen reception may sharpen fuzzy memory
Estrogen treatments may sharpen mental performance in women with certain medical conditions, but University of Florida researchers suggest that recharging a naturally occurring estrogen receptor in the brain may also clear cognitive cobwebs.
Hip bone density helps predict breast cancer risk
Measuring a woman's bone mineral density can provide additional information that may help more accurately determine a woman's risk of developing breast cancer.
More Breast Cancer News Articles
 | Courageous Souls: Do We Plan Our Life Challenges Before Birth? by Robert Schwartz Courageous Souls explores the premise that we are all eternal souls who plan our lives, including our greatest challenges, before we re born for purposes of spiritual growth. The book contains ten true stories of people who planned physical illness, having handicapped children, deafness, blindness, drug addiction, alcoholism, losing a loved one, and severe accidents. Because very different life... |
 | What Your Doctor May Not Tell You About Menopause (TM): The Breakthrough Book on Natural Hormone Balance by John R. Lee, Virginia Hopkins The classic bestseller that has helped nearly a million women discover the answer to menopause is now revised and updated. Hot flashes, night sweats, weight gain, low sex drive, hair loss, fibroids, and osteoporosis-most women will experience these or other hormone- related problems at some point as they age. In clear, easy-to-understand language, an internationally recognized expert explains the... |
 | Dr. Susan Love's Breast Book:4th Edition 2005 by Susan Love Dr. Susan Love's Breast Book has been considered the bible of breast-care books since it appeared in 1990. In 1995, Love completely updated the book in a 600-page second edition, including new biopsy and screening methods, implants, the pros and cons of hormone therapy, new discoveries in breast-cancer treatment, and many other topics. Every chapter has been rewritten, with the exception of the... |
 | The Middle Place (Voice) by Kelly Corrigan "The Middle Place is about calling home. Instinctively. Even when all the paperwork -- a marriage license, a notarized deed, two birth certificates, and seven years of tax returns -- clearly indicates you're an adult, but all the same, there you are, clutching the phone and thanking God that you're still somebody's daughter." For Kelly Corrigan, family is everything. At thirty-six, she had a... |
 | 7 Weeks to Safe Social Drinking: How to Effectively Moderate Your Alcohol Intake by Donna J. Cornett Drink less, crave less and nip your problem drinking in the bud with the easy Drink/Link Moderate Drinking Program in this book! Drink/Link has helped thousands of drinkers worldwide to control drinking and prevent alcoholism since 1988. Over 80% of the drinkers who have completed this program have either cut their drinking in half or significantly reduced it! No meetings, drugs, belief in a... |
 | Refuge: An Unnatural History of Family and Place by Terry Tempest Williams The only constants in nature are change and death. Terry Tempest Williams, a naturalist and writer from northern Utah, has seen her share of both. The pages of Refuge resound with the deaths of her mother and grandmother and other women from cancer, the result of the American government's ongoing nuclear-weapons tests in the nearby Nevada desert. You won't find the episode in the standard history... |
 | Lopsided: How Having Breast Cancer Can Be Really Distracting by Meredith Norton A hilarious and wickedly irreverent look at life with cancerLopsided is not your ordinary cancer memoir. Meredith Norton chronicles every step of her experience, starting with her bizarre symptoms while living in Paris to moving back home to California and living with her compulsive parents and their five television sets. Irreverent and incredibly funny, Norton rails against self-pity and... |
 | The Breast Cancer Survivor's Fitness Plan (Harvard Medical School Guides) by Carolyn M. Kaelin, Francesca Coltrera, Josie Gardiner, Joy Prouty |
 | Just Get Me Through This!: The Practical Guide to Breast Cancer by Deborah A. Cohen, M.D., Robert M. Gelfand |
 | Rosen's Breast Pathology by Paul Peter Rosen Written by an internationally recognized expert in diagnostic breast pathology, this gold-standard text and reference is now in its revised, updated, and expanded Third Edition. It provides a comprehensive, extensively illustrated review of the clinical, radiological, pathological, and therapeutic aspects of the entire spectrum of breast diseases. More than 3,000 full-color... |
| © 2008 BrightSurf.com |