Blocking protein kills prostate cancer cells, inhibits tumor growth, Jefferson scientists findFebruary 28, 2008(PHILADELPHIA) Researchers at Jefferson's Kimmel Cancer Center in Philadelphia have shown that they can effectively kill prostate cancer cells in both the laboratory and in experimental animal models by blocking a signaling protein that is key to the cancer's growth. The work proves that the protein, Stat5, is both vital to prostate cancer cell maintenance and that it is a viable target for drug therapy. The scientists, led by Marja Nevalainen, M.D., Ph.D., associate professor of Cancer Biology at Jefferson Medical College of Thomas Jefferson University, wanted to prove that Stat5 was indeed necessary for prostate cancer cells to be viable. They blocked the protein's expression and function in several ways, including siRNA inhibition, antisense inhibition and adenoviral gene delivery of an inhibitory form of Stat5. All of these techniques killed the prostate cancer cells in cell culture. The researchers also showed when they transplanted such cancerous tissue into mice and blocked Stat5 expression, prostate tumors failed to grow. "This provides the proof of principle that Stat5 is a therapeutic target protein for prostate cancer, and may be specifically useful for advanced prostate cancer, where there are no effective therapies," Dr. Nevalainen says. "These results are very reproducible." She and her team report their findings March 1, 2008 in the journal Clinical Cancer Research. Hormone resistant prostate cancer is especially dangerous. Men with primary prostate cancer usually have either surgery or radiation, whereas subsequent disease is frequently treated by hormone therapy. But if the cancer recurs again, years later, it can be more aggressive and typically fails to respond to hormone treatment, often leaving few treatment options. The findings, Dr. Nevalainen notes, are particularly relevant because her team worked with urologists to get human prostate cancer tissue specimens from surgeries, putting them into cell tissue cultures. That way, she says, the hypothesis could be tested in real human prostate cancer tissue specimens. While she and her team continue to work on establishing Stat5 as a therapeutic target for hormone-resistant prostate cancer, they are also testing whether or not blocking Stat5 can make prostate cancer cells more sensitive to other treatments, such as radiation and chemotherapy. Another next step in the work, Dr. Nevalainen says, is to find pharmacological agents that inhibit the protein. In work reported recently in Cancer Research, Dr. Nevalainen and her co-workers showed that Stat5 is turned on in nearly all recurrent prostate cancers that are resistant to hormone therapy. In addition, the researchers also showed that the convergence of Stat5 and androgen receptor could be responsible for making such prostate cancers especially dangerous. Thomas Jefferson University |
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| Related Prostate Cancer Current Events and Prostate Cancer News Articles Does prostate-specific antigen velocity help in early detection prostate cancer? The November issue of European Urology, the official journal of the European Association of Urology, features an article focussing on prostate specific antigen (PSA) velocity and early cancer detection. It has been suggested that changes in PSA over time aid prostate cancer detection. New Synthetic Molecules Trigger Immune Response to HIV and Prostate Cancer Researchers at Yale University have developed synthetic molecules capable of enhancing the body's immune response to HIV and HIV-infected cells, as well as to prostate cancer cells. Their findings, published online in the Journal of the American Chemical Society, could lead to novel therapeutic approaches for these diseases. Chemo-radiation before prostate removal may prevent cancer recurrence Researchers in the Oregon Health & Science University Knight Cancer Institute and the Portland Veterans Affairs Medical Center have found a combination of radiation therapy and chemotherapy given before prostate removal is safe and may have the potential to reduce cancer recurrence and improve patient survival. Blood vessels might predict prostate cancer behavior A diagnosis of prostate cancer raises the question for patients and their physicians as to how the tumor will behave. Will it grow quickly and aggressively and require continuous treatment, or slowly, allowing therapy and its risks to be safely delayed? Short-term hormone therapy and intermediate dose radiation increases survivial for early stage prostate cancer Short-term hormone therapy given prior to and during intermediate dose radiation treatment for men with early stage prostate cancer increases their chance of living longer, compared to those who receive the same radiation alone. Task force develops new radiation guidelines for brachytherapy Radiation dose delivered to the prostate and nearby organs in every brachytherapy procedure should be carefully analyzed using post-implant CT or MRI and uniformly documented in every patient. 1 disease, not 1 demographic The Asian continent has nearly four billion people living in 47 different countries, and each of these groups has their own unique set of health issues. But when they come to the United States, they're often lumped into one large demographic: "Asian/Pacific Islander." Cancer survivors may not be getting the help they need to stop smoking More than a quarter of cancer survivors who still smoke have not been advised to quit smoking by their health care providers in the last year, according to a study published by researchers at Fox Chase Cancer Center in the current issue of the Journal of General Internal Medicine. Experts issue call to reconsider screening for breast cancer and prostate cancer Twenty years of screening for breast and prostate cancer - the most diagnosed cancer for women and men - have not brought the anticipated decline in deaths from these diseases, argue experts from the University of California, San Francisco and the University of Texas Health Science Center at San Antonio in an opinion piece published in the "Journal of the American Medical Association." Detecting the undetectable in prostate cancer screening A team of Northwestern University researchers, using an extremely sensitive tool based on nanotechnology, has detected previously undetectable levels of prostate-specific antigen (PSA) in patients who have undergone radical prostatectomy. More Prostate Cancer Current Events and Prostate Cancer News Articles |
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