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:10/13/2017)... ... October 13, 2017 , ... Southern ... and Jennifer Huggins, PharmD ’17, along with clinical associate professor Janice Frueh, ... cardiovascular diseases during the 15th Annual Women’s Health Conference. The SIU School ...
(Date:10/13/2017)... (PRWEB) , ... October 13, 2017 , ... Apple ... care services, staged a mock evacuation of the facility as part of a disaster ... Fire Department, Echo Hose EMS and Shelton City Emergency Manager, as well as the ...
(Date:10/13/2017)... RIDGE, N.J. (PRWEB) , ... October 13, 2017 , ... ... annual Holly Day Market. Featuring a collection of specialty vendors and unique items from ... of personalized and quality-focused health and wellness services offered by the VNA. The ...
(Date:10/13/2017)... NJ (PRWEB) , ... October 13, 2017 , ... Global ... at scenic Alexandria Park in Milford, NJ. This free event, sponsored by Global ... physical activity. The fun run is geared towards children of all ages; it ...
(Date:10/13/2017)... ... October 13, 2017 , ... ... giving viewers the lowdown on sciatica in a new episode of "Success Files," ... on current events and innovation and investigates each subject in-depth with passion and ...
Breaking Medicine News(10 mins):
(Date:9/28/2017)... 28, 2017 Cohen Veterans Bioscience and Early ... of wearable and home sensors for real-time monitoring of ... Foundation, a nonprofit organization focused on disruptive health solutions ... affordable analytical system to record and integrate behavioral, cognitive, ... ...
(Date:9/23/2017)... Sept. 22, 2017 Janssen Biotech, Inc. (Janssen) ... letter from the U.S. Food and Drug Administration (FDA) ... sirukumab for the treatment of moderately to severely active ... clinical data are needed to further evaluate the safety ... active RA. ...
(Date:9/18/2017)... KALAMAZOO, Mich. , Sept. 18, 2017 /PRNewswire/ ... and OptiMed Specialty Pharmacy of Kalamazoo, Mich. ... a strategic hub service that expedites and streamlines patient ... spirometer, Spiro PD 2.0, and wellness management services.  ... a medical device used to measure lung function for ...
Breaking Medicine Technology: