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 August 1, 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 August 1, 2014).

Share This




More Health & Medicine News

Friday, August 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

House Republicans Vote to Sue Obama Over Healthcare Law

House Republicans Vote to Sue Obama Over Healthcare Law

Reuters - US Online Video (July 31, 2014) The Republican-led House of Representatives votes to sue President Obama, accusing him of overstepping his executive authority in making changes to the Affordable Care Act. Mana Rabiee reports. Video provided by Reuters
Powered by NewsLook.com
Despite Health Questions, E-Cigs Are Beneficial: Study

Despite Health Questions, E-Cigs Are Beneficial: Study

Newsy (July 31, 2014) Citing 81 previous studies, new research out of London suggests the benefits of smoking e-cigarettes instead of regular ones outweighs the risks. Video provided by Newsy
Powered by NewsLook.com
Dangerous Bacteria Kills One in Florida

Dangerous Bacteria Kills One in Florida

AP (July 31, 2014) Sarasota County, Florida health officials have issued a warning against eating raw oysters and exposing open wounds to coastal and inland waters after a dangerous bacteria killed one person and made another sick. (July 31) Video provided by AP
Powered by NewsLook.com
Health Insurers' Profits Slide

Health Insurers' Profits Slide

Reuters - Business Video Online (July 30, 2014) Obamacare-related costs were said to be behind the profit plunge at Wellpoint and Humana, but Wellpoint sees the new exchanges boosting its earnings for the full year. Fred Katayama reports. Video provided by Reuters
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