Featured Research

from universities, journals, and other organizations

Deficiency in p53 anti-tumor protein delays DNA repair after radiation

Date:
April 23, 2013
Source:
H. Lee Moffitt Cancer Center & Research Institute
Summary:
Researchers have found that a deficiency in an important anti-tumor protein, p53, can slow or delay DNA repair after radiation treatment. They suggest that this is because p53 regulates the expression of two enzymes (JMJD2b and SUV39H1) that control the folding of DNA.

Researchers at Moffitt Cancer Center have found that a deficiency in an important anti-tumor protein, p53, can slow or delay DNA repair after radiation treatment. They suggest that this is because p53 regulates the expression of two enzymes (JMJD2b and SUV39H1) that control the folding of DNA.

According to the researchers, p53 is highly inducible by radiation. Activation of p53 stabilizes chromosomes by promoting the repair of heterochromatin DNA, which controls the expression of nearby genes and ensures accurate distribution of chromosomes during cell division.

Their findings, which published online Feb. 4 in Oncogene, are significant because they shed light on the consequence of p53 deficiency that frequently occurs in tumors and further explain the function of p53 in the development of cancer.

Crucial to multicellular organisms, p53 is a tumor suppressor that regulates the cell cycle and helps prevent cancer by maintaining genetic stability and inhibiting gene mutation. But after irradiation, p53 deficiency results in abnormal levels of SUV39H1 and JMJD2b, enzymes that play a vital role in the structure of chromosomes, especially in DNA damage control and repair.

"Different tumor types have variable responses to ionizing radiation," explained study lead author Jiandong Chen, Ph.D., senior member of the Cancer Biology and Molecular Medicine Program at Moffitt. "Radiation therapy is more effective if tumors are defective in repairing damaged DNA. The p53 pathway is compromised to different degrees in all tumors, which may explain the fact that radiation often kills tumor cells more than normal cells."

In this study, the researchers worked with multiple cancer cell lines.

"We found that p53 activates JMJD2b and represses SUV39H1," Chen said. "Depletion of JMJD2b, or sustained expression of SUV39H1, delays the repair of heterochromatin DNA after ionizing radiation," explained Chen. "The DNA repair function of p53 may be particularly important in higher organisms because of the increased complexity of their genomes."

Although they note that there is no general consensus on the relationship between p53 mutation status and treatment response, in certain narrow settings such as breast cancer, p53 mutation is associated with favorable response to chemotherapy.

"We can conclude that the chromatin modifiers SUV39H1 and JMJD2b are important mediators of p53 function in maintaining the stability of highly repetitive DNA sequences, and developing new drugs that target these enzymes may benefit cancer therapy," the researchers wrote.

This work is supported by grants from the National Institutes of Health (CA141244, CA109636).


Story Source:

The above story is based on materials provided by H. Lee Moffitt Cancer Center & Research Institute. Note: Materials may be edited for content and length.


Journal Reference:

  1. H Zheng, L Chen, W J Pledger, J Fang and J Chen. p53 promotes repair of heterochromatin DNA by regulating JMJD2b and SUV39H1 expression. Oncogene, 2013 DOI: 10.1038/onc.2013.6

Cite This Page:

H. Lee Moffitt Cancer Center & Research Institute. "Deficiency in p53 anti-tumor protein delays DNA repair after radiation." ScienceDaily. ScienceDaily, 23 April 2013. <www.sciencedaily.com/releases/2013/04/130423091119.htm>.
H. Lee Moffitt Cancer Center & Research Institute. (2013, April 23). Deficiency in p53 anti-tumor protein delays DNA repair after radiation. ScienceDaily. Retrieved September 3, 2014 from www.sciencedaily.com/releases/2013/04/130423091119.htm
H. Lee Moffitt Cancer Center & Research Institute. "Deficiency in p53 anti-tumor protein delays DNA repair after radiation." ScienceDaily. www.sciencedaily.com/releases/2013/04/130423091119.htm (accessed September 3, 2014).

Share This



More Health & Medicine News

Wednesday, September 3, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Snack Attack: Study Says Action Movies Make You Snack More

Snack Attack: Study Says Action Movies Make You Snack More

Newsy (Sep. 2, 2014) You're more likely to gain weight while watching action flicks than you are watching other types of programming, says a new study published in JAMA. Video provided by Newsy
Powered by NewsLook.com
U.N. Says Ebola Travel Restrictions Will Cause Food Shortage

U.N. Says Ebola Travel Restrictions Will Cause Food Shortage

Newsy (Sep. 2, 2014) The U.N. says the problem is two-fold — quarantine zones and travel restrictions are limiting the movement of both people and food. Video provided by Newsy
Powered by NewsLook.com
Doctors Fear They're Losing Battle Against Ebola

Doctors Fear They're Losing Battle Against Ebola

AP (Sep. 2, 2014) As a third American missionary is confirmed to have contracted Ebola in Liberia, doctors on the ground in West Africa fear they're losing the battle against the outbreak. (Sept. 2) Video provided by AP
Powered by NewsLook.com
Tech Giants Bet on 3D Headsets for Gaming, Healthcare

Tech Giants Bet on 3D Headsets for Gaming, Healthcare

AFP (Sep. 2, 2014) When Facebook acquired the virtual reality hardware developer Oculus VR in March for $2 billion, CEO Mark Zuckerberg hailed the firm's technology as "a new communication platform." Duration: 02:24 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:
from the past week

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