Featured Research

from universities, journals, and other organizations

Researchers Discover A Common Protein's Deadly Role In Breast Cancer

Date:
April 27, 1999
Source:
University Of California, San Francisco
Summary:
Scientists analyzing human breast tumors have discovered that the tumors produce large amounts of a "fetal" form of a protein that can spur uncontrolled cancerous growth.

Scientists analyzing human breast tumors have discovered that the tumors produce large amounts of a "fetal" form of a protein that can spur uncontrolled cancerous growth.

Related Articles


The findings, published in part in the May issue of Molecular and Cellular Biology and in part in the May issue of the journal Oncogene, pinpoint a clear target for new cancer drugs, the researchers say. Turning off this unsuspected fetal form of the protein would rob tumors of a potent cancer growth stimulant. The protein is one form of the insulin receptor. Its other -- "adult" -- form is a crucial part of the pathway that lowers blood sugar.

Until now, it was assumed that in tumors, insulin primarily linked up with its adult receptor to metabolize sugars and other nutrients. But the researchers found that in breast tumors the principal form of the insulin receptor appears instead to be the growth-stimulating "fetal" form.

"We have found that in these cancers, the insulin receptor largely reverts to its fetal stage, where its prime mission is to spur rapid cell division," said Ira D. Goldfine, MD, professor of medicine and physiology at the University of California San Francisco and co-author of the two scientific papers. Many cancers are known to express fetal proteins, he added.

In addition to its value in developing new drug strategies to control breast cancer, the research finding may offer a more immediate message, Goldfine suggests.

"Breast cancer has both genetic and lifestyle components," he says. "We know that both a sedentary lifestyle and obesity cause levels of insulin to rise excessively. This rise, in turn, activates insulin receptors. Now that we have found -- to our surprise -- that the fetal insulin receptor is overproduced in breast tumors, it would seem that women who are prone to develop breast cancer are at greater risk if they are sedentary or obese because they may have more insulin available to activate fetal insulin receptors.

"We're not saying that the insulin receptor causes breast cancer," he stressed, "but it is possible that it aids or stimulates tumor growth once the tumor has been established."

In examinations of human breast cancer cells and human breast tumor specimens, the scientists discovered that the insulin receptor is present in two slightly different forms - small amounts of the familiar adult form which binds only insulin, and larger amounts of the fetal form which can bind either insulin or a related growth factor known as IGF-II. It is when the fetal form docks with insulin or IGF-II that rapid cell division ensues, stimulating cancer growth, the researchers found.

"In the breast tumors, the fetal form binds to both insulin and to IGF-II to stimulate tumor growth," said Goldfine. "Because of this process, the fetal form of the insulin receptor now appears to be a clear target for drugs to block or slow breast tumor growth."

The Molecular and Cellular Biology paper established that a shortened form of the insulin receptor, known as IR-A, is the fetal form, or growth-stimulating form, and that it is activated by the growth-inducing protein IGF-II. The Oncogene paper reported the group's discovery that the fetal form of the insulin receptor is "over-produced" in breast cancers, and that it is activated in breast tumors by IGF-II.

The research is a collaboration between UCSF's Goldfine and two laboratories in Italy. Senior author on the paper in Molecular and Cellular Biology is Riccardo Vigneri, MD, professor of medicine at the University of Catania. Senior author on the paper in Oncogene is Antonio Belfiore, MD, at the same institution. The laboratory of Paolo Sbraccia, MD, at the University of Rome also played a key role.

Co-authors on both papers, along with Goldfine, Vigneri and Belfiore, are Franceso Frasca, MD, Giueseppe Pandini, MD, Pierluigi Scalia, MD, Laura Sciacca, MD, Rosanna Mineo, MD, Angela Constantino, MD, all of University of Catania. Pablo Sbraccia, of the Unviersity of Rome is co-author only on the Oncogene paper.


Story Source:

The above story is based on materials provided by University Of California, San Francisco. Note: Materials may be edited for content and length.


Cite This Page:

University Of California, San Francisco. "Researchers Discover A Common Protein's Deadly Role In Breast Cancer." ScienceDaily. ScienceDaily, 27 April 1999. <www.sciencedaily.com/releases/1999/04/990427045523.htm>.
University Of California, San Francisco. (1999, April 27). Researchers Discover A Common Protein's Deadly Role In Breast Cancer. ScienceDaily. Retrieved October 30, 2014 from www.sciencedaily.com/releases/1999/04/990427045523.htm
University Of California, San Francisco. "Researchers Discover A Common Protein's Deadly Role In Breast Cancer." ScienceDaily. www.sciencedaily.com/releases/1999/04/990427045523.htm (accessed October 30, 2014).

Share This



More Health & Medicine News

Thursday, October 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Mind-Controlled Prosthetic Arm Restores Amputee Dexterity

Mind-Controlled Prosthetic Arm Restores Amputee Dexterity

Reuters - Innovations Video Online (Oct. 29, 2014) A Swedish amputee who became the first person to ever receive a brain controlled prosthetic arm is able to manipulate and handle delicate objects with an unprecedented level of dexterity. The device is connected directly to his bone, nerves and muscles, giving him the ability to control it with his thoughts. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Google To Use Nanoparticles, Wearables To Detect Disease

Google To Use Nanoparticles, Wearables To Detect Disease

Newsy (Oct. 29, 2014) Google X wants to improve modern medicine with nanoparticles and a wearable device. It's all an attempt to tackle disease detection and prevention. Video provided by Newsy
Powered by NewsLook.com
Can Drinking Milk Lead To Early Death?

Can Drinking Milk Lead To Early Death?

Newsy (Oct. 29, 2014) Researchers in Sweden released a study showing heavy milk drinkers face an increased mortality risk from a variety of causes. Video provided by Newsy
Powered by NewsLook.com
Obama: The US Will Not 'run and Hide' From Ebola

Obama: The US Will Not 'run and Hide' From Ebola

AP (Oct. 29, 2014) Surrounded by health care workers in the White House East Room, President Barack Obama said the U.S. will likely see additional Ebola cases in the weeks ahead. But he said the nation can't seal itself off in the fight against the disease. (Oct. 29) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

    Technology News



    Save/Print:
    Share:

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile: iPhone Android Web
    Follow: Facebook Twitter Google+
    Subscribe: RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins