Featured Research

from universities, journals, and other organizations

Leukemia Drug Turns Mini-molecules Up, Cancer Genes Down

Date:
March 5, 2007
Source:
Ohio State University
Summary:
New research shows that a form of vitamin A used to treat acute promyelocytic leukemia induces changes in an unusual class of small molecules called microRNAs (miRNAs) in the leukemic cells. The study also shows that three of these miRNAs inhibit the action of two genes important for cancer development, helping to explain how the drug works.

New research shows that a form of vitamin A used to treat acute promyelocytic leukemia induces changes in an unusual class of small molecules called microRNAs (miRNAs) in the leukemic cells.

Related Articles


The study also shows that three of these miRNAs inhibit the action of two genes important for cancer development, helping to explain how the drug works.

The drug is called all-trans-retinoic acid (ATRA) and it is considered the gold standard for treating the disease.

The study showed that ATRA raises the levels of three particular miRNAs in leukemia cells and that this rise coincides with a fall in activity of two important cancer-causing genes. The three are identified as miRNA-15b, miRNA-16-1 and let-7.

Two of these, miRNA-15b and miRNA-16-1, reduce the activity of the Bcl-2 gene, which is over-active in many kinds of cancer. The protein produced by this gene blocks the normal process of cell death and helps keep cancer cells alive long after they should have died.

The remaining miRNA molecule, let-7, lowered the activity of the Ras oncogene, an important cancer-causing gene. (Oncogenes are normal genes that when mutated lead to cancer.)

Researchers at the Ohio State University Comprehensive Cancer Center led the study, which was published in a recent issue of the journal Oncogene.

“The findings are important because they tell us that some miRNAs switch off genes that promote cancer,” says first author Ramiro Garzon, a hematologist and oncologist at Ohio State's James Cancer Hospital and Solove Research Institute.

Acute promyelocytic leukemia occurs when cells that give rise to a form of white blood cell become stuck at an immature stage. The immature cells accumulate until they crowd out healthy white cells in the blood and bone marrow.

“Our findings suggest that these three miRNAs help re-program the malignant cells to a more normal state,” Garzon says, “and that they are also important for normal differentiation.”

In this study, the researchers used leukemia cells grown in the laboratory and cells donated by patients to study how the drug ATRA affects miRNA levels and how those changes affect the cells.

The investigators exposed the leukemia cells to the drug for up to 96 hours, causing the cells to mature. The treatment increased the level of eight miRNAs and a drop in one compared with untreated cells.

Of these, the researchers focused on miRNA-15b and miRNA-16-1, which are known to regulate the activity of the Bcl-2 gene. They found that high levels of the two miRNAs were associated with low Bcl-2 activity.

Next, they showed that the two miRNAs actually caused the drop in Bcl-2 activity. They did this by adding additional amounts of the two miRNAs to leukemia cells not treated with ATRA. Restoring the miRNAs caused a strong drop in Bcl-2 levels.

The researchers then looked at miRNA let-7, a known regulator of the Ras oncogene, and likewise found that high levels of this miRNA were associated with low Ras activity.

They established a cause and effect relationship as before, by adding additional let-7 to untreated leukemia cells.

“Overall,” Garzon says, “our findings show that ATRA induces the expression of these three miRNAs, and through them regulates genes that need to be silenced for the cell to differentiate.”

Funding from the National Cancer Institute, the Paul and Mary Haas Chair in Genetics, a Lauri Strauss Discovery grant award, the Kimmel Foundation and the CLL Global Research Foundation supported this research.


Story Source:

The above story is based on materials provided by Ohio State University. Note: Materials may be edited for content and length.


Cite This Page:

Ohio State University. "Leukemia Drug Turns Mini-molecules Up, Cancer Genes Down." ScienceDaily. ScienceDaily, 5 March 2007. <www.sciencedaily.com/releases/2007/03/070302082555.htm>.
Ohio State University. (2007, March 5). Leukemia Drug Turns Mini-molecules Up, Cancer Genes Down. ScienceDaily. Retrieved October 31, 2014 from www.sciencedaily.com/releases/2007/03/070302082555.htm
Ohio State University. "Leukemia Drug Turns Mini-molecules Up, Cancer Genes Down." ScienceDaily. www.sciencedaily.com/releases/2007/03/070302082555.htm (accessed October 31, 2014).

Share This



More Health & Medicine News

Friday, October 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Fauci Says Ebola Risk in US "essentially Zero"

Fauci Says Ebola Risk in US "essentially Zero"

AP (Oct. 30, 2014) NIAID Director Anthony Fauci said the risk of Ebola becoming an epidemic in the U.S. is essentially zero Thursday at the Washington Ideas Forum. He also said an Ebola vaccine will be tested in West Africa in the next few months. (Oct. 30) Video provided by AP
Powered by NewsLook.com
Nurse Defies Ebola Quarantine With Bike Ride

Nurse Defies Ebola Quarantine With Bike Ride

AP (Oct. 30, 2014) A nurse who vowed to defy Maine's voluntary quarantine for health care workers who treated Ebola patients followed through on her promise Thursday, leaving her home for an hour-long bike ride. (Oct. 30) Video provided by AP
Powered by NewsLook.com
Pot-Infused Edibles Raise Concerns in Colorado

Pot-Infused Edibles Raise Concerns in Colorado

AFP (Oct. 30, 2014) Colorado may have legalized marijuana for recreational use, but the debate around the decision still continues, with a recent - failed - attempt to ban cannabis-infused edibles. Duration: 01:53 Video provided by AFP
Powered by NewsLook.com
British Navy Ship Arrives in Sierra Leone With Ebola Aid

British Navy Ship Arrives in Sierra Leone With Ebola Aid

AFP (Oct. 30, 2014) The British ship RFA ARGUS arrived in Sierra Leone to deliver supplies and equipment to help the fight against Ebola. Duration: 00:42 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