Featured Research

from universities, journals, and other organizations

Targeting 'normal' cells in tumors slows growth, researchers show

Date:
November 17, 2009
Source:
The Wistar Institute
Summary:
Targeting the normal cells that surround cancer cells within and around a tumor is a strategy that could greatly increase the effectiveness of traditional anti-cancer treatments, say researchers.

Targeting the normal cells that surround cancer cells within and around a tumor is a strategy that could greatly increase the effectiveness of traditional anti-cancer treatments, say researchers at The Wistar Institute.

Related Articles


In the Journal of Clinical Investigation published online November 16, they demonstrate the critical role for fibroblast activation protein (FAP), expressed by one type of these so-called "stromal" cells, in promoting tumor growth in mice. Genetically deleting or therapeutically targeting FAP significantly reduced the rate of tumor growth in mice by interrupting or blocking important signaling pathways and biological processes required for tumor growth, the Wistar team found.

"It's like taking away the soil from a seed that wants to grow," says senior author Ellen Puré, Ph.D., a professor in the Molecular and Cellular Oncogenesis Program at Wistar. "These results provide a proof-of-principle that targeting and modifying a tumor's microenvironment may be an effective approach to treating solid tumors."

Tumors are a complex mix of neoplastic cancer cells and normal cells -- inflammatory and immune cells, endothelial cells, fibroblasts, pericytes, and others, collectively known as stromal cells. In addition, a web-like extracellular matrix is created by the stromal cells, and its structure is important for supporting and nurturing tumor growth through molecular signaling pathways.

The Wistar team focused on fibroblasts and pericytes. In addition to synthesizing components of the extracellular matrix, fibroblasts associated with tumors also express FAP, a particular protease that cuts up other proteins while pericytes are important to the function of the new blood vessels that develop in tumors. FAP is expressed in 90 percent of all human epithelial (solid) cancers, and FAP expression is recognized as a marker for and is thought to play a role in cancer growth, but the mechanisms through which this occurs had been previously unknown.

"Our data clearly demonstrate that FAP indeed promotes the growth of colon cancer as well as lung cancer in animal models, and provide insight into how FAP works," says Puré. To explore how FAP promotes tumor growth, lead author Angélica Santos, Ph.D., and colleagues took two approaches -- genetic deletion and pharmacologic targeting of FAP to determine the effects of deactivating FAP in mouse models of lung and colon cancer.

First, they examined the genetic deletion of FAP. In collaboration with Wistar assistant professor and co-author Joseph Kissil, Ph.D., they mated mice engineered to spontaneously develop lung cancer when their K-Ras gene is activated with mice whose FAP gene had been deleted to develop a new strain of mice with a genetic deletion of FAP and expressing an activated K-Ras gene.

The Wistar team found that lung tumor growth was substantially inhibited in these mice. In another experiment the investigators transplanted colon cancer cells into FAP-deficient mice and saw a similarly marked inhibition of tumor growth.

"We found that FAP inactivation disrupts the organization of the collagen fibers which are a key component of matrix and that could be critical for many things, including cell to cell communication, cell-matrix interactions and development of new blood vessels to feed the tumors," Puré says. "The organization or architecture of the matrix is important to supporting both stromal and cancer cells within a tumor. If stromal cells depend on this matrix for structural support and to communicate with the cancer, they can't do that properly if it is drastically modified as we observed in the absence of FAP activity. "

To explore the potential for a therapeutic approach, the investigators used a novel peptide agent, PT630, to shut down FAP activation in the lung and colon cancer mice. Again, they found a significant reduction in tumor growth by inhibiting the enzymatic activity of FAP with this candidate drug agent.

"This proof of concept is the first step toward the clinic," Puré says. "We need more drugs that target the non-cancer cells in tumors, which can then be combined with specific chemotherapies and biologic drugs to attack both the tumor and its supporting cells."

One of the benefits of such a strategy, Puré adds, is that a limited number of agents would likely be required to treat many different cancers, because stromal cells tend to have common properties and share expression of the FAP protein in most tumor types. Comparatively, targeted therapies designed for specific tumor types -- such as breast or colon -- will likely require a wide variety of different drugs.

The only agents currently used to treat cancer by targeting the tumor microenvironment are anti-angiogenesis drugs, like Avastin, which disrupt blood vessel formation to tumors.

The study was funded by grants from the National Institutes of Health, the Pennsylvania Department of Health, the Cancer Research Institute, the Ludwig Institute for Cancer Research and a Wistar Cancer Training Grant. Agents used in the study were provided by Point Therapeutics. The authors declare no conflict of interest.


Story Source:

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


Cite This Page:

The Wistar Institute. "Targeting 'normal' cells in tumors slows growth, researchers show." ScienceDaily. ScienceDaily, 17 November 2009. <www.sciencedaily.com/releases/2009/11/091116173205.htm>.
The Wistar Institute. (2009, November 17). Targeting 'normal' cells in tumors slows growth, researchers show. ScienceDaily. Retrieved November 24, 2014 from www.sciencedaily.com/releases/2009/11/091116173205.htm
The Wistar Institute. "Targeting 'normal' cells in tumors slows growth, researchers show." ScienceDaily. www.sciencedaily.com/releases/2009/11/091116173205.htm (accessed November 24, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Monday, November 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola-Hit Sierra Leone's Late Cocoa Leaves Bitter Taste

Ebola-Hit Sierra Leone's Late Cocoa Leaves Bitter Taste

AFP (Nov. 23, 2014) — The arable district of Kenema in Sierra Leone -- at the centre of the Ebola outbreak in May -- has been under quarantine for three months as the cocoa harvest comes in. Duration: 01:32 Video provided by AFP
Powered by NewsLook.com
Don't Fall For Flu Shot Myths

Don't Fall For Flu Shot Myths

Newsy (Nov. 23, 2014) — Misconceptions abound when it comes to your annual flu shot. Medical experts say most people older than 6 months should get the shot. Video provided by Newsy
Powered by NewsLook.com
WFP: Ebola Risks Heightened Among Women Throughout Africa

WFP: Ebola Risks Heightened Among Women Throughout Africa

AFP (Nov. 21, 2014) — Having children has always been a frightening prospect in Sierra Leone, the world's most dangerous place to give birth, but Ebola has presented an alarming new threat for expectant mothers. Duration: 00:37 Video provided by AFP
Powered by NewsLook.com
Could Your Genes Be The Reason You're Single?

Could Your Genes Be The Reason You're Single?

Newsy (Nov. 21, 2014) — Researchers in Beijing discovered a gene called 5-HTA1, and carriers are reportedly 20 percent more likely to be single. 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