Molecule blocks gene, sheds light on liver cancer

Aug 01, 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: Quarter of prostate cancer patients may abandon 'watchful waiting' approach

add to favorites email to friend print save as pdf

Related Stories

World's first successful visualisation of key coenzyme

2 hours ago

Japanese researchers have successfully developed the world's first imaging method for visualising the behaviour of nicotine-adenine dinucleotide derivative (NAD(P)H), a key coenzyme, inside cells. This feat ...

The promise and peril of nanotechnology

Mar 26, 2014

Scientists at Northwestern University have found a way to detect metastatic breast cancer by arranging strands of DNA into spherical shapes and using them to cover a tiny particle of gold, creating a "nano-flare" ...

Hot nanoparticles for cancer treatments

Mar 24, 2014

Nanoparticles have a great deal of potential in medicine: for diagnostics, as a vehicle for active substances or a tool to kill off tumours using heat. ETH Zurich researchers have now developed particles ...

New technology detect cellular memory

Feb 24, 2014

Cells in our body are constantly dividing to maintain our body functions. At each division, our DNA code and a whole machinery of supporting components has to be faithfully duplicated to maintain the cell's ...

Recommended for you

Unraveling the 'black ribbon' around lung cancer

9 hours ago

It's not uncommon these days to find a colored ribbon representing a disease. A pink ribbon is well known to signify breast cancer. But what color ribbon does one think of with lung cancer?

User comments : 0

More news stories

Turning off depression in the brain

Scientists have traced vulnerability to depression-like behaviors in mice to out-of-balance electrical activity inside neurons of the brain's reward circuit and experimentally reversed it – but there's ...

Researchers discover target for treating dengue fever

Two recent papers by a University of Colorado School of Medicine researcher and colleagues may help scientists develop treatments or vaccines for Dengue fever, West Nile virus, Yellow fever, Japanese encephalitis and other ...

Our brains are hardwired for language

A groundbreaking study published in PLOS ONE by Prof. Iris Berent of Northeastern University and researchers at Harvard Medical School shows the brains of individual speakers are sensitive to language univer ...

Study recalculates costs of combination vaccines

One of the most popular vaccine brands for children may not be the most cost-effective choice. And doctors may be overlooking some cost factors when choosing vaccines, driving the market toward what is actually a more expensive ...

Better thermal-imaging lens from waste sulfur

Sulfur left over from refining fossil fuels can be transformed into cheap, lightweight, plastic lenses for infrared devices, including night-vision goggles, a University of Arizona-led international team ...

Hackathon team's GoogolPlex gives Siri extra powers

(Phys.org) —Four freshmen at the University of Pennsylvania have taken Apple's personal assistant Siri to behave as a graduate-level executive assistant which, when asked, is capable of adjusting the temperature ...