Master gene SRC-3 enables breast cancer growth, invasion

Feb 12, 2010

The master gene called SRC-3 (steroid receptor coactivator 3) not only enhances estrogen-dependent growth of cancer cells by activating and encouraging the transcription of a genetic message into a protein, it also sends a signal to the cell membrane to promote cell motility or movement - a key element of cancer spread or metastasis, said Baylor College of Medicine researchers and collaborators in a report that appears in the current issue of the journal Molecular Cell.

The finding not only uncovers a new activity for SRC-3 at the cell's periphery, it also clears up a mystery about how the message that tells a cell to invade gets from the (EGFR) to the activating enzyme called FAK (focal adhesion kinase) found on the cell's membrane, said Dr. Bert O'Malley, chair of molecular and cellular biology at BCM and the report's senior author.

"Two-thirds of breast cancers over express the gene SRC-3," said O'Malley, who is the 2008 National Medal of Science recipient. "The work represented in this paper shows that a coactivator gene (SRC-3) can produce an alternative form of its coactivator protein - a shorter form that is missing the part of the protein that keeps it in the nucleus. With that portion (called an exon) gone, it leaves the nucleus and goes into the cytoplasm (or general area of the cell) and travels to the membrane," he said.

"At the membrane, the enzyme PAK1 (p21-activted kinase 1) phosphorylates (attaches a phosphate molecule that activates the coactivator) SRC-3, allowing it to function at the membrane," said O'Malley, responsible for identifying the first receptor coactivator and advancing the field in general.

The finding explains how the epidermal growth factor receptor at the membrane gets a signal to the enzyme that tells the cell to move - and ultimately grow, allowing the cancer to invade surrounding tissue, said O'Malley.

"Now we have a final picture as to why epidermal growth factor receptor and the estrogen receptor are the most dangerous combination of molecules overproduced in breast ," said O'Malley. "When they are both over functioning, people die quickly and are resistant to therapy."

Explore further: Chronic inflammation linked to 'high-grade' prostate cancer

More information: www.cell.com/molecular-cell/home

add to favorites email to friend print save as pdf

Related Stories

Deactivating a cancer growth promoter

Sep 25, 2008

Three enzymes called phosphatases that shut down a molecule called SRC-3 (steroid receptor coactivator 3) could provide a new pathway for fighting cancer, particularly tumors of the breast and prostate, said researchers at ...

Clocking in and out of gene expression

Jun 14, 2007

A chemical signal acts as time clock in the expression of genes controlled by a master gene called a coactivator, said Baylor College of Medicine researchers in a report that appears in the journal Cell today.

Protein inhibits cancer cell growth

Dec 21, 2009

(PhysOrg.com) -- Researchers at the University of Toronto and Goethe University in Germany have discovered a protein that can inhibit the growth of cancer cells, providing crucial clues for the future development of new drugs ...

Recommended for you

Unraveling the 'black ribbon' around lung cancer

Apr 17, 2014

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

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Study says we're over the hill at 24

(Medical Xpress)—It's a hard pill to swallow, but if you're over 24 years of age you've already reached your peak in terms of your cognitive motor performance, according to a new Simon Fraser University study.

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.