Featured Research

from universities, journals, and other organizations

Potential new way to suppress tumor growth discovered

Date:
June 3, 2013
Source:
University of California, San Diego Health Sciences
Summary:
Researchers have identified a new mechanism that appears to suppress tumor growth, opening the possibility of developing a new class of anti-cancer drugs.

Researchers at the University of California, San Diego School of Medicine, with colleagues at the University of Rochester Medical Center, have identified a new mechanism that appears to suppress tumor growth, opening the possibility of developing a new class of anti-cancer drugs.

Related Articles


Writing in this week's online Early Edition of the Proceedings of the National Academy of Sciences (PNAS), Willis X. Li, PhD, a professor in the Department of Medicine at UC San Diego, reports that a particular form of a signaling protein called STAT5A stabilizes the formation of heterochromatin (a form of chromosomal DNA), which in turn suppresses the ability of cancer cells to issue instructions to multiply and grow.

Specifically, Li and colleagues found that the unphosphorylated form of STAT promotes and stabilizes heterochromatin, which keeps DNA tightly packaged and inaccessible to transcription factors. "Therefore, genes 'buried' in heterochromatin are not expressed," explained Li.

Phosphorylation is a fundamental cellular function in which a phosphate group is added to a protein or molecule, causing it to turn it on or off or to alter its function. An unphosphorylated STAT lacks this phosphate group.

Li said that in previous studies with fruit flies, the unphosphorylated form of STAT caused chromatin to condense into heterochromatin, while the phosphorylated version prompted dispersal and loss of heterochromatin, furthering gene expression.

"Unphosphorylated STAT promotes and stabilizes heterochromatin formation, which in turn suppresses gene transcription," said Li. "When we expressed either HP1 (the central component of heterochromatin) or unphosphorylated STAT5A in human cancer cells, many genes important for cancer growth are suppressed. These cancer cells do not grow as fast or big as their control parental cancer cells in mouse xenograft models."

Most of the known tumor suppressors, such as p53 or Rb, function by inhibiting cell cycle progression or by spurring cell death, or apoptosis. Li said their findings reveal a potential new way to inhibit cancer gene expression, and may represent a new class of tumor suppressors.

"We are in the process of identifying small molecule drugs that may promote heterochromatin formation without stopping cell division or causing cell death," he said. "These drugs, if found, may be effective in treating cancers with fewer side effects."

Co-authors are Xiaoyu Hu, Amy Tsurumi and Hartmut Land, Department of Biomedical Genetics, University of Rochester Medical Center; Pranabananda Dutta, Jinghong Li and Jingtong Wang, Department of Medicine, UCSD.

Funding for this research came, in part, from the National Institutes of Health grants R01CA131326 and RO1CA138249 and a Leukemia & Lymphoma Society Research Scholar grant.


Story Source:

The above story is based on materials provided by University of California, San Diego Health Sciences. Note: Materials may be edited for content and length.


Journal Reference:

  1. Xiaoyu Hu, Pranabananda Dutta, Amy Tsurumi, Jinghong Li, Jingtong Wang, Hartmut Land, and Willis X. Li. Unphosphorylated STAT5A stabilizes heterochromatin and suppresses tumor growth. PNAS, 2013 DOI: 10.1073/pnas.1221243110

Cite This Page:

University of California, San Diego Health Sciences. "Potential new way to suppress tumor growth discovered." ScienceDaily. ScienceDaily, 3 June 2013. <www.sciencedaily.com/releases/2013/06/130603163613.htm>.
University of California, San Diego Health Sciences. (2013, June 3). Potential new way to suppress tumor growth discovered. ScienceDaily. Retrieved November 29, 2014 from www.sciencedaily.com/releases/2013/06/130603163613.htm
University of California, San Diego Health Sciences. "Potential new way to suppress tumor growth discovered." ScienceDaily. www.sciencedaily.com/releases/2013/06/130603163613.htm (accessed November 29, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Saturday, November 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Rural India's Low-Cost Sanitary Pad Revolution

Rural India's Low-Cost Sanitary Pad Revolution

AFP (Nov. 28, 2014) — One man hopes his invention -– a machine that produces cheap sanitary pads –- will help empower Indian women. Duration: 01:51 Video provided by AFP
Powered by NewsLook.com
Research on Bats Could Help Develop Drugs Against Ebola

Research on Bats Could Help Develop Drugs Against Ebola

AFP (Nov. 28, 2014) — In Africa's only biosafety level 4 laboratory, scientists have been carrying out experiments on bats to understand how virus like Ebola are being transmitted, and how some of them resist to it. Duration: 01:18 Video provided by AFP
Powered by NewsLook.com
WHO Says Male Ebola Survivors Should Abstain From Sex

WHO Says Male Ebola Survivors Should Abstain From Sex

Newsy (Nov. 28, 2014) — WHO cites four studies that say Ebola can still be detected in semen up to 82 days after the onset of symptoms. Video provided by Newsy
Powered by NewsLook.com
Ebola Leaves Orphans Alone in Sierra Leone

Ebola Leaves Orphans Alone in Sierra Leone

AFP (Nov. 27, 2014) — The Ebola epidemic sweeping Sierra Leone is having a profound effect on the country's children, many of whom have been left without any family members to support them. Duration: 01:02 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins