Scientists show that a microRNA can reduce lung cancer growth

A small RNA molecule, known as let-7 microRNA (miRNA), substantially reduced cancer growth in multiple mouse models of lung cancer, according to work by researchers at Yale University and Asuragen, Inc., published in the journal Cell Cycle.

Cancer afflicts 1.5 million people a year in the United States alone, and lung cancer is the most common and deadly form of cancer worldwide. This study indicates a direct role for a miRNA in cancer progression and introduces a new paradigm of using miRNAs as effective therapeutic agents to treat human cancer.

“We believe this is the first report of a miRNA being used to a beneficial effect on any cancer, let alone lung cancers, the deadliest of all cancers worldwide,” said senior author Frank Slack, associate professor of molecular, cellular and developmental biology at Yale.

Slack’s research group initially discovered the let-7 miRNA in C. elegans, a tiny worm used as a model system for studying how organisms develop, grow and age. They went on to show that in humans, let-7 negatively regulates a well-known determinant of human lung cancers, the RAS oncogene.

In collaboration with scientists at Asuragen, the Slack lab has studied the tumor suppressor activity of this small RNA. Their work revealed that let-7 is commonly present at substantially reduced levels in lung tumors — and that reduced levels of let-7 likely contribute to the development of the tumors. These discoveries focused public attention and research efforts to understand the potential use of naturally occurring microRNAs like let-7 to combat cancer.

This new work demonstrates that let-7 inhibits the growth of lung cancer cells in culture and in lung tumors in mice. They also showed that let-7 can be applied as an intranasal drug to reduce tumor formation in a RAS mouse model lung cancer.

“We believe that our studies provide the first direct evidence in mammals, that let-7 functions as a tumor suppressor gene,” said Slack. “Because multiple cell lines and mouse models of lung cancer were used, it appears that therapeutic application of let-7 may provide benefits to a broad group of lung cancer patients.”

“This has been a very productive industry-academic collaboration between Yale and Asuragen scientists” commented Matt Winkler CEO of Asuragen. “This work provides further evidence of the importance of miRNAs in the development of cancer and provides additional support for miRNA replacement therapy as an important component of effective cancer treatment regimens of the future.”

Source: Yale University

Related stories:

Gene panel predicts lung cancer survival, study finds
Researchers from four leading cancer centers have confirmed that an analysis involving a panel of genes can be used to predict which lung cancer patients will have the worst survival. The finding could one day lead to a test that would help determine who needs more aggressive treatment. The study, the largest of its kind, appears online in Nature Medicine.
New approach to cancer: Find most tightly controlled genes
Scientists at a Duke University medical school in Singapore have found a new way to study cancer that could be very useful for developing targeted therapies against cancer and possibly many other diseases.
Report: Invest $10 a person for better health
(AP) -- Investing just $10 per person - roughly the price of a six-pack of beer and some chips - could greatly fuel community programs that get couch potatoes moving, prevent smoking and improve nutrition, researchers say.
As rates rise, researchers find better way to identify melanoma
University of Rochester Medical Center researchers found a new protein produced excessively in malignant melanoma, a discovery that is particularly relevant as skin cancer rates climb dramatically among young women.
Vitamin A pushes breast cancer to form blood vessel cells
Researchers at Georgetown University Medical Center have discovered that vitamin A, when applied to breast cancer cells, turns on genes that can push stem cells embedded in a tumor to morph into endothelial cells. These cells can then build blood vessels to link up to the body's blood supply, promoting further tumor growth.
An alternative to chemotherapy: Nanoparticles tackle pediatric brain tumors
An interdisciplinary team of researchers at Washington University in St. Louis, led by Karen L. Wooley, Ph.D., James S. McDonnell Distinguished University Professor in Arts & Sciences, is a step closer to delivering cancer-killing drugs to pediatric brain tumors, similar to the tumor that Senator Ted Kennedy is suffering from.
Magnolia compound hits elusive target in cancer cells
A natural compound from magnolia cones blocks a pathway for cancer growth that was previously considered "undruggable," researchers have found.
Study finds arsenic threats in SE Asia
(AP) -- Myanmar's cyclone-devastated Irrawaddy delta and Indonesia's Sumatra island face high risks of arsenic contamination in groundwater that could cause cancer and other diseases in residents, according to a new study.

News discussion:

Medicine & Health news