Navigation Links
Protein that suppresses androgen receptors could improve prostate cancer diagnosis, treatment
Date:5/20/2009

AUGUSTA, Ga. A protein that helps regulate expression of androgen receptors could prove a new focal point for staging and treating testosterone-fueled prostate cancer, Medical College of Georgia researchers say.

Levels of the protein, βarrestin2, are lower in some prostate cancer cells than in normal prostate cells while expression of testosterone-fed androgen receptors is higher, they report in Proceedings of the National Academy of Sciences Online Early Edition this week.

"An increase in the number of androgen receptors is believed responsible for prostate cancer progression in men with advanced disease," says the study's corresponding author, Dr. Yehia Daaka, Distinguished Chair in Oncologic Pathology in the MCG School of Medicine.

With increased numbers of androgen receptors, prostate cancer can make use of the limited testosterone available after a diseased prostate gland is removed or after testosterone production is blocked by drug therapy. In fact, the increased number of androgen receptors may mutate so they can start feeding off other steroids or even growth factors, Dr. Daaka says.

These wily skills help explain why cancer returns despite initially promising treatment results.

"It is clear that signaling by the androgen receptor is paramount for not only the initiation but also the progression of the disease, including escape to a hormone-refractory disease," he says. Moves androgen receptors make to support cancer growth make it "unbeatable at this point," for some patients.

However increased levels of βarrestin2 appear to halt the potentially deadly increase in androgen receptor expression, the MCG research team has found.

Androgen receptors have co-factors that can activate or repress their activity. "You could make the leap and say perhaps prostate cancer initiation and progression may be regulated by expression or non-expression of these co-factors," says Dr. Daaka, a Georgia Cancer Coalition Distinguished Cancer Scholar.

Their studies in human tissue both in culture and transplanted into mice show this appears the case for βarrestin2. First the team identified βarrestin2 as cofactor for androgen receptors. Next they found a reciprocal relationship: androgen receptor expression is low when βarrestin2 expression increases. That's the scenario in healthy prostate cells while the exact opposite is true in some prostate cancer. When they forced increased expression of βarrestin2, androgen receptor expression and activity went down.

βarrestin2 locks up an androgen receptor by binding to it, then the pair bind to yet another protein, ubiquitin ligase, which tags the receptor as waste and the trio make their way to the cell's garbage dump. "The neat thing about it is βarrestin2 inhibits or blunts the androgen receptor by promoting its degradation. So it disappears," Dr. Daaka says.

His future studies include determining what happens when βarrestin2 expression is further decreased in the face of prostate cancer. These studies will also help determine how big a player βarrestin2 is in prostate cancer progression, says Dr. Daaka, noting that numerous other corepressors and activators of androgen receptors are known.

Since all the happenings occur inside prostate cells, the findings don't point toward a new blood or urine test for prostate cancer but could lead to new ways to stage prostate cancer from the first biopsy. In fact, Dr. Daaka and his team already are collecting samples from patients whose cancer has been staged to see if specific levels of βarrestin2 expression correlate with different stages of disease.

Another goal is to develop a small molecule that can get inside a patient's cell and mimic βarrestin2's ability to suppress androgen receptor expression and so restore healthy levels found in prostate cells.

Prostate cancer falls behind skin cancer as the second most common cancer in men and more than 192,000 new cases will be diagnosed this year in the United States, according to the American Cancer Society.


'/>"/>

Contact: Toni Baker
tbaker@mcg.edu
706-721-4421
Medical College of Georgia
Source:Eurekalert  

Related medicine news :

1. Fear Response May Stem From Protein in Brain
2. Researchers identify key proteins needed for ovulation
3. Protein Might Mute Effects of Methamphetamine
4. Omega Protein Reports 2009 First Quarter Results
5. Protein Sciences Corporation Appoints New Board of Directors
6. Upside-down world: DNA protecting protein helps cancer drug to kill cells
7. Novel role of protein in generating amyloid-beta peptide
8. Scripps research scientists model 3D structures of proteins that control human clock
9. Key protein in cellular respiration discovered
10. Protein Might Be a Troublesome Nutrient
11. Protein-Folding Problem May Help Spur Alzheimers
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Protein that suppresses androgen receptors could improve prostate cancer diagnosis, treatment
(Date:6/27/2016)... ... June 27, 2016 , ... ... today announced its strategic partnership with Connance, a healthcare industry leader providing ... companies’ proven, proprietary technology combine to provide health systems, hospitals and ambulatory ...
(Date:6/26/2016)... ... ... Pixel Film Studios Released ProSlice Levels, a Media Slicing Effect Plugin ... whole new perspective by using the title layers in ProSlice Levels to split-up ... Levels contains over 30 Different presets to choose from. FCPX users can ...
(Date:6/25/2016)... ... June 25, 2016 , ... Austin residents seeking Mohs surgery services, can now ... and to Dr. Russell Peckham for medical and surgical dermatology. , Dr. Dorsey brings ... The selective fellowship in Mohs Micrographic Surgery completed by Dr. Dorsey was under the ...
(Date:6/25/2016)... (PRWEB) , ... June 25, 2016 , ... ... athletes and non-athletes recover from injury. Recently, he has implemented orthobiologic procedures as ... City area —Johnson is one of the first doctors to perform the treatment. ...
(Date:6/24/2016)... ... ... June 19, 2016 is World Sickle Cell Observance Day. In an effort ... holistic treatments, Serenity Recovery Center of Marne, Michigan, has issued a pain ... Disease (SCD) is a disorder of the red blood cells, which can cause episodes ...
Breaking Medicine News(10 mins):
(Date:6/24/2016)...   Bay Area Lyme Foundation , collaborating ... for Tick Borne Illness , Harvard Medical School ... Medicine, University of California, Berkeley, and the Veterans ... finalists of Lyme Innovation , the first ... scientists, clinicians, researchers, entrepreneurs, and investors from several ...
(Date:6/24/2016)... June 24, 2016 Dehaier Medical Systems Ltd. ... which develops, markets and sells medical devices and wearable ... signed a strategic cooperation agreement with Hongyuan Supply Chain ... Chain") on June 20, 2016, to develop Dehaier,s new ... cooperation agreement, Dehaier will leverage Hongyuan Supply Chain,s sales ...
(Date:6/24/2016)... , June 24, 2016   Pulmatrix, Inc ... company developing innovative inhaled drugs, announced today that it ... Russell Investments reconstituted its comprehensive set of U.S. ... "This is an important milestone for Pulmatrix," said ... increase shareholder awareness of our progress in developing drugs ...
Breaking Medicine Technology: