Featured Research

from universities, journals, and other organizations

New Role For Brain Chemical Found In Mammary Glands, With Implications For Breast Cancer Research

Date:
May 12, 2003
Source:
University Of California, Santa Cruz
Summary:
Researchers at the University of California, Santa Cruz, have discovered a new role for a molecule long associated with brain development: orchestrating the growth of mammary glands during puberty. The findings may have important implications for the development of breast cancer.

SANTA CRUZ, CA -- Researchers at the University of California, Santa Cruz, have discovered a new role for a molecule long associated with brain development: orchestrating the growth of mammary glands during puberty. The findings may have important implications for the development of breast cancer.

The molecule, a signaling protein called netrin-1, has been intensively studied for its role in guiding the growth of nerve cells. The UCSC researchers, led by assistant professor of molecular, cell and developmental biology Lindsay Hinck, are the first to show a function for netrin-1 outside the nervous system.

"This was a really new concept because everybody knew about netrin-1 in the nervous system, but no one had a clue about what it did outside the nervous system," said Karpagam "Shalu" Srinivasan, a graduate student who helped make the discovery.

For nine years, Hinck has studied the role of netrin-1 in directing the development of the embryonic nervous system. Netrins are one of four major families of molecular signals that guide growing nerve cells to their targets, ultimately producing the elaborate network of connections that makes up the nervous system. When netrins connect with specific receptors on a nerve cell's surface, they prompt changes in the cell that cause it to grow toward or away from the area where netrins are concentrated.

But other researchers had found netrin-1 in different tissues, as well, suggesting additional roles for the molecule.

"About two and a half years ago I decided to start a whole new direction in the lab," Hinck said.

She decided to figure out what netrin-1 does in mammary tissue, one of the places where it had been detected. Both Hinck and Srinivasan had studied the nervous system, and the new project combined their expertise with that of research assistant Phyllis Strickland, who had done breast cancer research in another lab. Undergraduate students Ana Valdes and Grace Shin also helped with the research. The group's findings appeared in the March issue of the journal Developmental Cell.

During puberty, the mammary gland grows into the fat pad, led by the vigorous growth and branching of the gland's tips, called end buds.

"During puberty, these end buds are just plowing along at half a millimeter a day into the fat pad," Hinck said.

Hinck's group theorized that netrin-1 might guide the buds in the same way it guides nerve cells in the embryonic brain. Instead, the researchers found that it functions as a kind of glue, holding the cells of the end bud together.

Getting end bud cells to stick together in the breast may seem quite different from guiding brain cells toward or away from a target, but Hinck sees the two functions as different sides of the same coin.

"In the nervous system netrin-1 functions as a long-range cue to establish neural connections, and in the mammary gland netrin-1 acts as a short-range cue to assemble cells into an organized structure," she said.

Hinck's lab examined the effects of netrin-1 in mice. To study the role of a protein in a model organism, researchers usually "knock out" the gene that codes for that protein and see what happens. Hinck's group compared the development of mammary glands with and without the netrin-1 gene.

Both the normal and the knockout glands grew in a way that appeared normal at first look. But where end buds of normal mammary glands have tightly adhering layers of cells, each with its own function, the cell layers in the knockout buds were widely spaced and disorganized.

The researchers observed the same effect when they knocked out the gene for neogenin, a known receptor for netrin-1 in the brain. This is strong evidence that neogenin is acting as the receptor for netrin-1 in the mammary gland. As with netrin-1, Hinck's group was the first to discover a function for neogenin outside the nervous system.

"Our studies showed for the first time that without neogenin, you can see something going wrong with early mammary gland development," said Srinivasan.

Both the netrin-1 and the neogenin knockouts displayed breaks in the basal lamina, the membrane surrounding the end bud of the mammary gland. When tumors develop, an intact basal lamina is essential to contain the tumor cells and prevent metastasis of the cancer. Because of this, Hinck believes mutations in the genes for netrin-1 or neogenin may be associated with invasive breast cancer.

The group plans to test samples of human tumors to see whether their netrin-1 or neogenin genes have mutations. Hinck's lab is also investigating the roles of other signaling molecules in the mammary gland.


Story Source:

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


Cite This Page:

University Of California, Santa Cruz. "New Role For Brain Chemical Found In Mammary Glands, With Implications For Breast Cancer Research." ScienceDaily. ScienceDaily, 12 May 2003. <www.sciencedaily.com/releases/2003/05/030512080810.htm>.
University Of California, Santa Cruz. (2003, May 12). New Role For Brain Chemical Found In Mammary Glands, With Implications For Breast Cancer Research. ScienceDaily. Retrieved September 1, 2014 from www.sciencedaily.com/releases/2003/05/030512080810.htm
University Of California, Santa Cruz. "New Role For Brain Chemical Found In Mammary Glands, With Implications For Breast Cancer Research." ScienceDaily. www.sciencedaily.com/releases/2003/05/030512080810.htm (accessed September 1, 2014).

Share This




More Health & Medicine News

Monday, September 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

We've Got Mites Living In Our Faces And So Do You

We've Got Mites Living In Our Faces And So Do You

Newsy (Aug. 30, 2014) A new study suggests 100 percent of adult humans (those over 18 years of age) have Demodex mites living in their faces. Video provided by Newsy
Powered by NewsLook.com
Liberia Continues Fight Against Ebola

Liberia Continues Fight Against Ebola

AFP (Aug. 30, 2014) Authorities in Liberia try to stem the spread of the Ebola epidemic by raising awareness and setting up sanitation units for people to wash their hands. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
California Passes 'yes-Means-Yes' Campus Sexual Assault Bill

California Passes 'yes-Means-Yes' Campus Sexual Assault Bill

Reuters - US Online Video (Aug. 30, 2014) California lawmakers pass a bill requiring universities to adopt "affirmative consent" language in their definitions of consensual sex, part of a nationwide drive to curb sexual assault on campuses. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
New Drug Could Reduce Cardiovascular Deaths

New Drug Could Reduce Cardiovascular Deaths

Newsy (Aug. 30, 2014) The new drug from Novartis could reduce cardiovascular deaths by 20 percent compared to other similar drugs. Video provided by Newsy
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:
from the past week

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