Molecule blocks gene, sheds light on liver cancer

August 1, 2007

New research shows how a particular small molecule blocks the activity of a cancer-suppressing gene, allowing liver-cancer cells to grow and spread.

This molecule is a microRNA, a recently discovered class of tiny molecules used by cells to help control the kinds and amounts of proteins they make. More than 250 different microRNAs have been discovered, and several have been linked to cancer.

These findings show exactly how one specific microRNA, called miR-21, helps cancer develop.

This molecule occurs at unusually high levels in many kinds of cancer cells. The study looked at a gene called PTEN (pronounced P-TEN), which normally protects cells from becoming cancerous. Researchers know that the abnormal silencing of this tumor-suppressor gene contributes to the development of liver cancer and other malignancies.

The findings help explain how liver cancer develops and may identify new drug targets for treating the disease. This particular microRNA might also provide a marker to help determine a patient's prognosis.

The study, led by researchers at the Ohio State University Comprehensive Cancer Center, is published in the August issue of the journal Gastroenterology.

“Our findings essentially describe a new mechanism used by cells to regulate PTEN,” says principal investigator Tushar Patel, professor of internal medicine, director of hepatology and a liver-cancer specialist at Ohio State University Medical Center.

They show that high levels of miR-21 block the PTEN gene, he explained. This, in turn, activates chemical pathways that enable cancer cells to proliferate, migrate and invade other tissues, all of which are features of tumor formation.

Patel and his collaborators began the study by measuring the relative levels of 197 microRNAs in normal liver cells and in liver cancer cells from human tumors and in four liver cancer cell lines.

Levels of miR-21 were up to nine times greater in liver-tumor tissue compared with normal liver tissue, twice that of the next highest microRNA.

Earlier research led by Patel had shown that miR-21 probably targeted PTEN, and this study confirmed that.

Furthermore, the researchers showed that adding high levels of miR-21 to normal liver cells caused PTEN levels to drop. They also traced the chemical pathways that increased the cells' abilities to proliferate, migrate and invade other tissues.

“Our findings indicate that miR-21 plays a fundamental role in tumor-cell behavior and cancer development,” Patel says, “and this may also be relevant to other tumors in which miR-21 is overexpressed. If this work is reproduced in investigations of other cancers, it could be a big step forward,” he says.

Source: Ohio State University

Explore further: Cell environment influences type of liver tumor

Related Stories

Cell environment influences type of liver tumor

September 13, 2018
Liver cancer is the second leading cause of cancer death worldwide. Two forms of primary liver cancer cover the majority of cases: About 10 to 20 percent of those affected develop a bile duct carcinoma within the liver (intrahepatic ...

Big data studies scrutinize links between fatty liver disease and how cells make energy

September 14, 2018
Nonalcoholic fatty liver disease affects up to 40 percent of American adults. Though the condition produces no noticeable symptoms, one out of every five people with it will go on to develop a more serious condition called ...

Study details incidence and timing of immunotherapy-related fatalities

September 13, 2018
Vanderbilt-Ingram Cancer Center researchers have answered questions about the incidence and timing of rare but sometimes fatal reactions to the most widely prescribed class of immunotherapies.

Tiny protein has big impact in times of stress

September 14, 2018
Ribosomes churn out proteins that carry out all of life's functions, but when missing a key and previously overlooked factor, they can break down in times of stress, Yale University scientists have discovered. 

Unlocking the secrets of cell division in cancer

August 29, 2018
Scientists at Hollings Cancer Center at the Medical University of South Carolina have found that some cells can divide without a molecule that was previously thought necessary. Their results, published online in the July ...

New target could prevent progression of liver damage to cancer

August 27, 2018
Problems like obesity and alcoholism appear to chronically trigger in the liver a receptor known to amplify inflammation in response to invaders like bacteria, scientists report.

Recommended for you

Fusion hybrids: A newly discovered population of tumor cells

September 24, 2018
In a recent study published in Science Advances, Charles E. Gast and co-workers detail the spontaneous process of cancer cell fusion with white blood cells to produce heterogenous hybrid clones in multiple biological systems, ...

Cancer cells evade immunotherapy by hiding telltale marker, suggesting how to stop relapse

September 24, 2018
Harnessing the immune system to treat cancer shows great promise in some patients, but for many, the response does not last long-term. In an effort to find out why, Fred Hutchinson Cancer Research Center scientists are using ...

In zebrafish, a way to find new cancer therapies, targeting tumor modulators

September 21, 2018
The lab of Leonard Zon, MD, at Boston Children's Hospital has long been interested in making blood stem cells in quantity for therapeutic purposes. Looking for a way to test for their presence in zebrafish, their go-to research ...

What can salad dressing tell us about cancer? Think oil and vinegar

September 20, 2018
Researchers led by St. Jude Children's Research Hospital scientists have identified another way the process that causes oil to form droplets in water may contribute to solid tumors, such as prostate and breast cancer. The ...

Novel biomarker found in ovarian cancer patients can predict response to therapy

September 20, 2018
Despite months of aggressive treatment involving surgery and chemotherapy, about 85 percent of women with high-grade wide-spread ovarian cancer will have a recurrence of their disease. This leads to further treatment, but ...

Testing fluorescent tracers used to help surgeons determine edges of breast cancer tumors

September 20, 2018
A team of researchers with members from institutions in The Netherlands and China has conducted a test of fluorescent tracers meant to aid surgeons performing tumor removal in breast cancer patients. In their paper published ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.