Featured Research

from universities, journals, and other organizations

Exosomal release of beta-catenin may explain why CD82 and CD9 suppress tumor metastasis

Date:
September 13, 2010
Source:
Rockefeller University Press
Summary:
Researchers reveal a new way in which cells restrain beta-catenin and potentially suppress tumor metastasis: the protein can be ejected from cells in small vesicles called exosomes.

Electron microscopy of purified cell culture supernatants reveals that cells overexpressing CD9 (middle) or CD82 (right) produce more exosomes than control cells (left). Exosomal release of beta-catenin and inhibition of Wnt signaling may explain why CD82 and CD9 suppress tumor metastasis.
Credit: Chairoungdua, A., et al. 2010. J. Cell Biol. doi:10.1083/jcb.201002049.

Researchers reveal a new way in which cells restrain beta-catenin and potentially suppress tumor metastasis: the protein can be ejected from cells in small vesicles called exosomes. The study appears online on September 13 in the Journal of Cell Biology.

Beta-catenin is a central component of the Wnt signaling pathway that controls cell proliferation and differentiation. Activation of the Wnt pathway stabilizes beta-catenin, allowing it to move into the cell nucleus and control the expression of many different genes.

Michael Caplan's group at Yale University uncovered a new way in which cells restrain beta-catenin's activity. Overexpressing CD82 or CD9, members of the tetraspanin family of transmembrane proteins, suppressed Wnt signaling and reduced beta-catenin protein levels. Surprisingly, this decrease did not involve an established pathway of beta-catenin destruction. "We were sort of stumped," Caplan admits, "until we saw a talk that mentioned that tetraspanins like CD82 are associated with exosomes."

Exosomes are small vesicles that form inside endosomes by the inward budding of endosomal membranes. The vesicles are then secreted when the endosome fuses with the plasma membrane. The team found that CD9 and CD82 boosted the release of exosomes containing beta-catenin, thereby reducing cellular levels of the protein and inhibiting the Wnt pathway. Cells lacking CD9, on the other hand, produced fewer exosomes and showed higher Wnt signaling activity.

The exosomal release of beta-catenin may be compromised in certain cancers, where Wnt signaling is often hyperactive. CD82 and CD9 are both suppressors of metastasis whose expression is lost in several types of late stage tumor. Caplan and colleagues blocked Wnt signaling in a metastatic cell line after restoring CD82 expression. "CD82 may act as a metastasis suppressor by targeting beta-catenin for exosomal release and thereby reducing its availability as a Wnt signaling mediator," Caplan proposes.


Story Source:

The above story is based on materials provided by Rockefeller University Press. Note: Materials may be edited for content and length.


Journal Reference:

  1. A. Chairoungdua, D. L. Smith, P. Pochard, M. Hull, M. J. Caplan. Exosome release of ?-catenin: a novel mechanism that antagonizes Wnt signaling. The Journal of Cell Biology, 2010; DOI: 10.1083/jcb.201002049

Cite This Page:

Rockefeller University Press. "Exosomal release of beta-catenin may explain why CD82 and CD9 suppress tumor metastasis." ScienceDaily. ScienceDaily, 13 September 2010. <www.sciencedaily.com/releases/2010/09/100913121610.htm>.
Rockefeller University Press. (2010, September 13). Exosomal release of beta-catenin may explain why CD82 and CD9 suppress tumor metastasis. ScienceDaily. Retrieved July 22, 2014 from www.sciencedaily.com/releases/2010/09/100913121610.htm
Rockefeller University Press. "Exosomal release of beta-catenin may explain why CD82 and CD9 suppress tumor metastasis." ScienceDaily. www.sciencedaily.com/releases/2010/09/100913121610.htm (accessed July 22, 2014).

Share This




More Health & Medicine News

Tuesday, July 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Gilead's $1000-a-Pill Drug Could Cure Hep C in HIV-Positive People

Gilead's $1000-a-Pill Drug Could Cure Hep C in HIV-Positive People

TheStreet (July 21, 2014) New research shows Gilead Science's drug Sovaldi helps in curing hepatitis C in those who suffer from HIV. In a medical study, the combination of Gilead's Hep C drug with anti-viral drug Ribavirin cured 76% of HIV-positive patients suffering from the most common hepatitis C strain. Hepatitis C and related complications have been a top cause of death in HIV-positive patients. Typical medication used to treat the disease, including interferon proteins, tended to react badly with HIV drugs. However, Sovaldi's %1,000-a-pill price tag could limit the number of patients able to access the treatment. TheStreet's Keris Lahiff reports from New York. Video provided by TheStreet
Powered by NewsLook.com
$23.6 Billion Awarded To Widow In Smoking Lawsuit

$23.6 Billion Awarded To Widow In Smoking Lawsuit

Newsy (July 20, 2014) Cynthia Robinson claims R.J. Reynolds Tobacco Company hid the health and addiction risks of its products, leading to the death of her husband in 1996. Video provided by Newsy
Powered by NewsLook.com
Tooth Plaque Provides Insight Into Diets Of Ancient People

Tooth Plaque Provides Insight Into Diets Of Ancient People

Newsy (July 19, 2014) Research on plaque from ancient teeth shows that our prehistoric ancestor's had a detailed understanding of plants long before developing agriculture. Video provided by Newsy
Powered by NewsLook.com
Contaminated Water Kills 3 Babies in South African Town

Contaminated Water Kills 3 Babies in South African Town

AFP (July 18, 2014) Contaminated water in South Africa's northwestern town of Bloemhof kills three babies and hospitalises over 500 people. The incident highlights growing fears over water safety in South Africa. Duration: 02:22 Video provided by AFP
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