Featured Research

from universities, journals, and other organizations

Common Cancer Gene Sends Death Order To Tiny Killer

Date:
May 31, 2007
Source:
Johns Hopkins Medical Institutions
Summary:
Scientists have discovered one way the p53 gene does what it's known for -- stopping the colon cancer cells. The research team identified a tiny bit of genetic code, a microRNA, that participates in p53's uncanny ability to kill cells likely to become malignant because of damaged genes in their nuclei.

Scientists at Johns Hopkins have discovered one way the p53 gene does what it's known for--stopping the colon cancer cells. Their report will be published in the June 8 issue of Molecular Cell.

The research team identified a tiny bit of genetic code, a microRNA called miR-34a that participates in p53's uncanny ability to kill cells likely to become malignant because of damaged genes in their nuclei. MicroRNAs are small chains of ribonucleic acid (RNA) made by the same machinery that produces other types of RNA in the cell, such as the messenger RNAs that carry the instructions to make proteins. Once produced, microRNAs stick to messenger RNAs and, like crumpled paper jammed in a copy machine, prevent proteins from being made.

Josh Mendell, M.D., Ph.D., an assistant professor in the McKusick-Nathans Institute of Genetic Medicine, suspected that p53 activates microRNAs like miR-34a because a number of studies have demonstrated that these tiny RNA molecules are frequently abnormal in cancer cells.

"P53 is one of the most commonly mutated genes in human cancers," says Mendell. "And there is now a great deal of evidence that microRNAs themselves can act to either promote cancer or to stop cancer spread."

To test their idea, the team first chemically damaged the DNA of two sets of colon cancer cells, one missing p53 and the other containing healthy p53. They then looked for any of the 500 known human microRNAs that are activated only in cells containing p53.

It turned out that the miR-34a gene is turned on by p53, and in fact, experiments demonstrated that p53 binds directly to the genetic material near miR-34a to promote its activation.

Concluding that p53 controls miR-34a, they next teamed up with Charlie Lowenstein, M.D., and his colleagues in Hopkins's department of medicine to put miR-34a into colon cancer cells. Doing this killed cells that contained p53, but fewer were killed in cells lacking p53, further suggesting that this microRNA gets its kill orders from p53.

When researchers examined pancreatic cancer cells known to contain damaged or missing p53, they found that those cells had limited or zero miR-34a.

"With no p53 gene or miR-34a to stem tumor development, there's no brake in pancreatic cells and uncontrolled growth leads to cancer," says Anirban Maitra, M.B.B.S., associate professor of pathology, oncology and genetic medicine.

Mendell and his team are looking for missing miR-34a in other cancers. If it's a widespread phenomenon, the work could lead to treatments that aim to restore the missing microRNA to cancer cells.

The research was funded by a Rita Allen Foundation Scholar Award, the Lustgarten Foundation for Pancreatic Cancer Research, the Sol Goldman Pancreatic Cancer Research Center, and the National Cancer Institute.

Authors on the paper are Tsung-Cheng Chang, Erik Wentzel, Oliver Kent, Kalyani Ramachandran, Michael Mullendore, Kwang Hyuck Lee, Georg Feldmann, Munekazu Yamakuchi, Marcella Ferlito, Charles Lowenstein, Dan Arking, Michael Beer, Anirban Maitra and Mendell, all of Hopkins.


Story Source:

The above story is based on materials provided by Johns Hopkins Medical Institutions. Note: Materials may be edited for content and length.


Cite This Page:

Johns Hopkins Medical Institutions. "Common Cancer Gene Sends Death Order To Tiny Killer." ScienceDaily. ScienceDaily, 31 May 2007. <www.sciencedaily.com/releases/2007/05/070531120830.htm>.
Johns Hopkins Medical Institutions. (2007, May 31). Common Cancer Gene Sends Death Order To Tiny Killer. ScienceDaily. Retrieved April 18, 2014 from www.sciencedaily.com/releases/2007/05/070531120830.htm
Johns Hopkins Medical Institutions. "Common Cancer Gene Sends Death Order To Tiny Killer." ScienceDaily. www.sciencedaily.com/releases/2007/05/070531120830.htm (accessed April 18, 2014).

Share This



More Health & Medicine News

Friday, April 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Scientists Create Stem Cells From Adult Skin Cells

Scientists Create Stem Cells From Adult Skin Cells

Newsy (Apr. 17, 2014) The breakthrough could mean a cure for some serious diseases and even the possibility of human cloning, but it's all still a way off. Video provided by Newsy
Powered by NewsLook.com
Obama: 8 Million Healthcare Signups

Obama: 8 Million Healthcare Signups

AP (Apr. 17, 2014) President Barack Obama gave a briefing Thursday announcing 8 million people have signed up under the Affordable Care Act. He blasted continued Republican efforts to repeal the law. (April 17) Video provided by AP
Powered by NewsLook.com
Is Apathy A Sign Of A Shrinking Brain?

Is Apathy A Sign Of A Shrinking Brain?

Newsy (Apr. 17, 2014) A recent study links apathetic feelings to a smaller brain. Researchers say the results indicate a need for apathy screening for at-risk seniors. Video provided by Newsy
Powered by NewsLook.com
Could Even Casual Marijuana Use Alter Your Brain?

Could Even Casual Marijuana Use Alter Your Brain?

Newsy (Apr. 16, 2014) A new study conducted by researchers at Northwestern and Harvard suggests even casual marijuana use can alter your brain. Video provided by Newsy
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