Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Lung cancer suppresses miR-200 to invade and spread

16.09.2009
Findings present possible avenue for preventing metastasis

Primary lung cancer shifts to metastatic disease by suppressing a family of small molecules that normally locks the tumor in a noninvasive state, researchers at The University of Texas M. D. Anderson Cancer Center report in the Sept. 15 edition of Genes and Development.

"Existing treatments have little success against cancer that has spread to other organs, so finding a way to prevent metastasis could have a huge impact on survival," said senior author Jonathan Kurie, M.D., professor in M. D. Anderson's Department of Thoracic/Head and Neck Medical Oncology.

"To do that, we need to understand the cues that initiate metastasis. In this paper we show that microRNA-200 is one of those central cues," Kurie said. MicroRNAs are single-stranded bits of RNA that regulate messenger RNA expressed by genes to order the creation of a specific protein.

All primary tumors in a strain of mice prone to metastatic lung cancer became invasive and spread when miR-200 was suppressed. Protecting miR-200 from blockade completely prevented metastasis in another group of the mice, the researchers found.

Tumors shift between noninvasive and invasive state

The team found that miR-200 needs to be shut down for the primary tumor to change from stationary epithelial cells to mobile mesenchymal cells. This epithelial-to-mesenchymal transition (EMT) is recognized as a crucial step in metastasis, which causes 90 percent of all cancer deaths.

An estimated 80 percent of all solid tumors originate in the epithelial cells, which line an organ or its cavities and are generally immobile. Mesenchymal cells are mobile and can differentiate into many different cell types.

When the team profiled a panel of 40 human lung cancer cell lines that had been characterized on the basis of EMT features (epithelial versus mesenchmyal) and site of origin (primary lung tumor versus metastasis), miR-200 expression was highest in those cells with epithelial features and was the best of more than 700 microRNAs tested as an indicator of metastatic or primary origin.

"Highly metastatic lung cancer cells had completely shutdown miR-200 expression, that's what triggered EMT in those cells," Kurie said. "When we went back and forced overexpression of miR-200, the cells remained locked in the epithelial state and could no longer metastasize."

The team also found that the cancer cells could shift from epithelial to mesenchymal and back depending on the cell's context. The same cells that remain epithelial in Matrigel become "blatantly mesenchymal" when moved to the mouse model and assume an intermediate state when growing in plastic dishes.

Matrigel is a gelatinous mixture that is designed to simulate the complex environment that cells occupy called the extracellular matrix.

"If you take the tumors out of the mice and back to the matrigel, they revert to epithelial cells," Kurie said. "These cells are highly plastic and responsive to the extracellular environment.

"The idea that these highly plastic cells are the source of metastasis indicates that metastatic capacity is a regulatable tumor cell function. That's new," Kurie said. "Identifying the signals that govern plasticity could lead to a novel way of targeting and preventing metastasis."

Kurie and colleagues continue to work on identifying upstream regulators of miR-200 that might provide targets for therapy.

The researchers started with a strain of mice that develops metastatic lung cancer based on mutations in the Kras oncogene and the tumor-suppressing p53 gene. Cell lines isolated from these mice were introduced in wild type mice and the resultant tumors characterized for metastatic potential.

All tumor cell lines were profiled for gene expression. "The thing that popped out strongly was an EMT signal present in the metastatic cells but not in the non-metastatic cells," Kurie said.

The team then profiled the tumors for microRNA expression. Out of thousands of miRNAs, only the miR-200 family of five miRNAs, along with three others, emerged as differentially expressed. The other three are being studied.

Co-authors with Kurie were first author Don Gibbons, M.D., Ph.D., Wei Lin, M.D., Zain Rizvi, and Nishan Thilaganathan, all of the Department of Thoracic/Head and Neck Medical Oncology; Chad Creighton, Ph.D., and Yiqun Zhang of the Dan L. Duncan Cancer Center at Baylor College of Medicine; Philip Gregory, Ph.D., and Gregory Goodall, Ph.D., of the Centre for Cancer Biology, Hanson Institute in Adelaide, Australia; and Alexander Pertsemlidis, Ph.D., and Liqin Du, Ph.D., of the Eugene McDermott Center for Human Growth and Development at The University of Texas Southwestern Medical Center in Dallas.

The research was funded by grants from the National Cancer Institute, including the Lung Cancer Specialized Program of Research Excellence; the David M. Sather Memorial Fund, the Armour Family Lung Cancer Research Fund and the Dan L. Duncan Cancer Center at Baylor College of Medicine. Gibbons also was supported by a Young Investigator Award from The ASCO Cancer Foundation and an International Association for the Study of Lung Cancer (IASLC) Fellow Grant.

About M. D. Anderson

The University of Texas M. D. Anderson Cancer Center in Houston ranks as one of the world's most respected centers focused on cancer patient care, research, education and prevention. M. D. Anderson is one of only 40 comprehensive cancer centers designated by the National Cancer Institute. For four of the past six years, including 2008, M. D. Anderson has ranked No. 1 in cancer care in "America's Best Hospitals," a survey published annually in U.S. News & World Report.

Scott Merville | EurekAlert!
Further information:
http://www.mdanderson.org

More articles from Life Sciences:

nachricht Molecular evolution: How the building blocks of life may form in space
26.04.2018 | American Institute of Physics

nachricht Multifunctional bacterial microswimmer able to deliver cargo and destroy itself
26.04.2018 | Max-Planck-Institut für Intelligente Systeme

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Why we need erasable MRI scans

New technology could allow an MRI contrast agent to 'blink off,' helping doctors diagnose disease

Magnetic resonance imaging, or MRI, is a widely used medical tool for taking pictures of the insides of our body. One way to make MRI scans easier to read is...

Im Focus: BAM@Hannover Messe: innovative 3D printing method for space flight

At the Hannover Messe 2018, the Bundesanstalt für Materialforschung und-prüfung (BAM) will show how, in the future, astronauts could produce their own tools or spare parts in zero gravity using 3D printing. This will reduce, weight and transport costs for space missions. Visitors can experience the innovative additive manufacturing process live at the fair.

Powder-based additive manufacturing in zero gravity is the name of the project in which a component is produced by applying metallic powder layers and then...

Im Focus: Molecules Brilliantly Illuminated

Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.

Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

World's smallest optical implantable biodevice

26.04.2018 | Power and Electrical Engineering

Molecular evolution: How the building blocks of life may form in space

26.04.2018 | Life Sciences

First Li-Fi-product with technology from Fraunhofer HHI launched in Japan

26.04.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>