Featured Research

from universities, journals, and other organizations

Protein and microRNA block cellular transition vital to metastasis

Date:
February 27, 2011
Source:
University of Texas M. D. Anderson Cancer Center
Summary:
Like a bounty hunter returning escapees to custody, a cancer-fighting gene converts organ cells that change into highly mobile stem cells back to their original, stationary state, researchers report.

Like a bounty hunter returning escapees to custody, a cancer-fighting gene converts organ cells that change into highly mobile stem cells back to their original, stationary state, researchers report online at Nature Cell Biology.

This newly discovered activity of the p53 gene offers a potential avenue of attack on breast cancer stem cells thought to play a central role in progression and spread of the disease, according to scientists at The University of Texas MD Anderson Cancer Center.

Long known for monitoring DNA damage and forcing defective cells to kill themselves, p53 also activates bits of RNA that block two proteins, the researchers found. This prevents conversion of epithelial-differentiated cells, which line or cover an organ, into cells that resemble mesenchymal stem cells when stimulated by the TGF-B(beta) growth factor.

Mesenchymal cells are mobile adult stem cells that can reproduce themselves and differentiate into a variety of cell types

"Blocking this conversion from epithelial cell to a mesenchymal cell type is important because that change plays an essential role in cancer metastasis," said senior author Mien-Chie Hung, Ph.D., professor and chair of MD Anderson's Department of Molecular and Cellular Oncology.

Cancer treatment potential

"We found that p53 activates the micro RNA miR-200c, which forces cells that have taken on stem cell traits to revert to epithelial form," Hung said. "Activating this pathway has therapeutic potential to target tumor-initiating cells that have stem cell characteristics."

Research has shown that about 80 percent of all solid tumors begin in the epithelial cells. However, 90 percent of cancer deaths are caused by metastasis, the progression and spread of the disease to other organs.

The epithelial-to-mesenchymal transition (EMT) and its opposite process play important roles in embryonic development. Research has connected EMT activation to cancer progression and metastasis. Recent studies tie EMT to gain of stem cell traits in normal and transformed cells.

Cell status depends on p53, miR-200c levels

A series of experiments established that the p53 protein activates the miR-200c gene to produce the microRNA and that expression of the protein and miR-200c moved up and down together.

  • Knockout experiments in normal breast epithelial cells consistently showed that p53 expression stifled the EMT transition.
  • Cells with reduced p53 changed into mesenchymal-like cells.
  • When miR-200c was overexpressed in cells with low levels of p53, the cells took on epithelial characteristics, indicating that p53 uses the microRNA to block or reverse the transition to mesenchymal-type cells.
  • Mutated p53 failed to produce miR-200c, increasing stem cells in the cell culture.
  • Tissue array analysis of gene expression in 106 human breast tumor samples showed that low p53 expression correlated with higher expression of two genes associated with EMT. Increased p53 raised levels of miR-200c and the expression of a gene associated with epithelial status.

Mutations of p53 occur in more than half of cancers and loss of p53 activity correlates with poor prognosis in several cancer types. Restoring functions lost by p53 mutation by re-expressing miR-200c might be a good therapeutic strategy for treatment of p53-deficient tumors, Hung said.

Research was funded by grants from the National Cancer Institute, including those for MD Anderson's Specialized Program in Research Excellence (SPORE) for breast cancer and MD Anderson's cancer center support grant; the National Breast Cancer Foundation, Inc.; the Breast Cancer Research Foundation; the MD Anderson-China Medical University and Hospital Sister Institution Fund; the National Science Council of Taiwan and the Cancer Research Center of Excellence, Taiwan Department of Health.

Co-authors with Hung, who also is MD Anderson vice president of basic research, are co-lead authors Chun-Ju Chang, Ph.D., and Chi-Hong Chao, Ph.D., Weiya Xia, M.D., Jer-Yen Yang, Ph.D., Yan Xiong, M.D., Chia-Wei Li, Ph.D., Wen-Hsuan Yu, Sumaiyah Rehman, Jennifer Hsu, Ph.D.,, Heng-Huan Lee, Mo Liu, Chun-Te Chen and Dihua Yu, M.D., Ph.D.

Yu, Rehman, Lee, Liu and Chen are graduate students in The University of Texas Graduate School of Biomedical Sciences, a joint operation of MD Anderson and The University of Texas Health Science Center at Houston (UTHealth).


Story Source:

The above story is based on materials provided by University of Texas M. D. Anderson Cancer Center. Note: Materials may be edited for content and length.


Journal Reference:

  1. Chun-Ju Chang, Chi-Hong Chao, Weiya Xia, Jer-Yen Yang, Yan Xiong, Chia-Wei Li, Wen-Hsuan Yu, Sumaiyah K. Rehman, Jennifer L. Hsu, Heng-Huan Lee, Mo Liu, Chun-Te Chen, Dihua Yu, Mien-Chie Hung. p53 regulates epithelial–mesenchymal transition and stem cell properties through modulating miRNAs. Nature Cell Biology, 2011; DOI: 10.1038/ncb2173

Cite This Page:

University of Texas M. D. Anderson Cancer Center. "Protein and microRNA block cellular transition vital to metastasis." ScienceDaily. ScienceDaily, 27 February 2011. <www.sciencedaily.com/releases/2011/02/110225164707.htm>.
University of Texas M. D. Anderson Cancer Center. (2011, February 27). Protein and microRNA block cellular transition vital to metastasis. ScienceDaily. Retrieved September 24, 2014 from www.sciencedaily.com/releases/2011/02/110225164707.htm
University of Texas M. D. Anderson Cancer Center. "Protein and microRNA block cellular transition vital to metastasis." ScienceDaily. www.sciencedaily.com/releases/2011/02/110225164707.htm (accessed September 24, 2014).

Share This



More Health & Medicine News

Wednesday, September 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola Costs Keep Mounting

Ebola Costs Keep Mounting

Reuters - Business Video Online (Sep. 23, 2014) The WHO has warned up to 20,000 people could be infected with Ebola over the next few weeks. As Sonia Legg reports, the implications for the West African countries suffering from the disease are huge. Video provided by Reuters
Powered by NewsLook.com
Ebola Cases Could Reach 1.4 Million Within 4 Months

Ebola Cases Could Reach 1.4 Million Within 4 Months

Newsy (Sep. 23, 2014) Health officials warn that without further intervention, the number of Ebola cases in Liberia and Sierra Leone could reach 1.4 million by January. Video provided by Newsy
Powered by NewsLook.com
WHO: Ebola Cases to Triple in Weeks Without Drastic Action

WHO: Ebola Cases to Triple in Weeks Without Drastic Action

AFP (Sep. 23, 2014) The number of Ebola infections will triple to 20,000 by November, soaring by thousands every week if efforts to stop the outbreak are not stepped up radically, the WHO warned in a study on Tuesday. Duration: 01:01 Video provided by AFP
Powered by NewsLook.com
5 Ways Men Can Prevent Most Heart Attacks

5 Ways Men Can Prevent Most Heart Attacks

Newsy (Sep. 23, 2014) No surprise here: A recent study says men can reduce their risk of heart attack by maintaining a healthy lifestyle, which includes daily exercise. 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:

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