Featured Research

from universities, journals, and other organizations

Mice with black fur that turns white help illuminate skin pigmentation

Date:
October 5, 2012
Source:
INSERM (Institut national de la santé et de la recherche médicale)
Summary:
Mice with black fur that turns white? Specialist cancer researchers have taken steps to better understand the development of skin cells responsible for pigmentation (known as melanocytes). By genetically manipulating mice with black fur, the researchers identified two key players: B-Raf and C-Raf proteins.

Mutant mice whose fur whitens as moulting progresses owing to a fault in self-renewal of melanocyte stem cells.
Credit: © A. Eychène / F. Bertrand (Institut Curie)

These proteins are required for melanocyte stem cell self-maintenance and, as such, correct pigmentation throughout the mice's life span. Without these two proteins, the mice's fur turns white. Their research is published in the review Cell Report and paves the way for serious possibilities in terms of stopping the formation of melanomas, tumours that originate from melanocyte cells.

Melanocytes are cells in the organism used for skin, fur and hair pigment. This pigmentation function provides protection from the sun and lends organisms their colour. Malfunctions in these cells may lead to skin cancer known as melanoma. Melanomas are highly aggressive cancers that become very difficult to treat as they develop and metastases occur.

A few years ago, researchers discovered that, in humans, the B-Raf gene (coding gene for protein of the same name) is mutated in more than 50% of melanoma. Spectacular progress has been made in recent years in the treatment of this cancer, thanks to the development of pharmacological inhibitors that target an enzyme: the B-Raf kinase. However, despite this treatment, cancer returns in several patients, indicating that not all cancerous cells have been eliminated. This led researchers to believe that B-Raf is not the only element driving the cancer process.

In this new research, scientists have tried to understand how melanocytes function normally, to then understand their specific role in cancer. To this end B-Raf protein expression, then, in turn, C-Raf protein expression, were removed from mice with black fur (ideal to clearly see any changes in pigmentation).

No changes in pigmentation were observed for mice that only had their B-Raf or C-Raf expression removed by researchers from the line of cells producing melanocytes. Mice that had both coding genes for B-Raf and C-Raf removed simultaneously had a normal colour at birth. However, they progressively lost their pigmentation as they grew. They turned grey from black, before becoming increasingly white.

For Alain Eychène, the research team leader, "these observations represent a fault in melanocyte renewal. Since the colour black is present at birth, the pigment cells clearly exist. However, the progressive whitening of the fur, once B-Raf and C-Raf have been removed from the cell line, proves that both these proteins are required for melanocyte renewal."

As is the case for all cells, melanocytes originate from stem cells; the latter are responsible for renewal during moulting. This research shows that it is specifically this population of stem cells alone that disappears progressively in mutant mice. For Alain Eychène, "This is the first in vivo demonstration of the role of RAF proteins in the self-renewal of stem cells."

The fact that B-Raf and C-Raf are both involved in controlling and renewing pigment stem cells represents another step towards understanding and treating melanoma. By blocking these proteins (using inhibitors) in patients undergoing treatment, it is possible that in time researchers will succeed in eliminating all cancerous stem cells, i.e. the likely cause behind cases of cancer reoccurrence.


Story Source:

The above story is based on materials provided by INSERM (Institut national de la santé et de la recherche médicale). Note: Materials may be edited for content and length.


Journal Reference:

  1. Agathe Valluet, Sabine Druillennec, Céline Barbotin, Coralie Dorard, Anne H. Monsoro-Burq, Magalie Larcher, Celio Pouponnot, Manuela Baccarini, Lionel Larue, Alain Eychène. B-Raf and C-Raf Are Required for Melanocyte Stem Cell Self-Maintenance. Cell Reports, 2012; DOI: 10.1016/j.celrep.2012.08.020

Cite This Page:

INSERM (Institut national de la santé et de la recherche médicale). "Mice with black fur that turns white help illuminate skin pigmentation." ScienceDaily. ScienceDaily, 5 October 2012. <www.sciencedaily.com/releases/2012/10/121005123809.htm>.
INSERM (Institut national de la santé et de la recherche médicale). (2012, October 5). Mice with black fur that turns white help illuminate skin pigmentation. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2012/10/121005123809.htm
INSERM (Institut national de la santé et de la recherche médicale). "Mice with black fur that turns white help illuminate skin pigmentation." ScienceDaily. www.sciencedaily.com/releases/2012/10/121005123809.htm (accessed July 25, 2014).

Share This




More Health & Medicine News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Beatings and Addiction: Pakistan Drug 'clinic' Tortures Patients

Beatings and Addiction: Pakistan Drug 'clinic' Tortures Patients

AFP (July 24, 2014) — A so-called drugs rehab 'clinic' is closed down in Pakistan after police find scores of ‘patients’ chained up alleging serial abuse. Duration 03:05 Video provided by AFP
Powered by NewsLook.com
Too Few Teens Receiving HPV Vaccination, CDC Says

Too Few Teens Receiving HPV Vaccination, CDC Says

Newsy (July 24, 2014) — The Centers for Disease Control and Prevention is blaming doctors for the low number of children being vaccinated for HPV. Video provided by Newsy
Powered by NewsLook.com
New Painkiller Designed To Discourage Abuse: Will It Work?

New Painkiller Designed To Discourage Abuse: Will It Work?

Newsy (July 24, 2014) — The FDA approved Targiniq ER on Wednesday, a painkiller designed to keep users from abusing it. Like any new medication, however, it has doubters. Video provided by Newsy
Powered by NewsLook.com
Doctor At Forefront Of Fighting Ebola Outbreak Gets Ebola

Doctor At Forefront Of Fighting Ebola Outbreak Gets Ebola

Newsy (July 24, 2014) — Sheik Umar Khan has treated many of the people infected in the Ebola outbreak, and now he's become one of them. 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