Featured Research

from universities, journals, and other organizations

Tumors Grow Faster Without Blood-supply Promoting Molecule

Date:
November 12, 2008
Source:
University of California - San Diego
Summary:
Dense networks of blood vessels thought to spur cancer's growth could actually hinder rather than promote tumor progression. The findings partly explain why drugs designed to treat cancer by strangling its blood supply have been disappointing when used alone and why those treatments are more effective when combined with traditional chemotherapy. Despite their rapid progression, tumors fed by more normal vascular were also more vulnerable to the effects of standard chemotherapy drugs.

Top: Blood marked with fluorescent dye spills from a tumor’s leaky vessels. Bottom: Without the growth factor, VEGF, blood vessels stay intact.
Credit: Image courtesy of University of California - San Diego

Dense networks of blood vessels thought to spur cancer’s growth could actually hinder rather than promote tumor progression, according to a new study at the University of California, San Diego.

The findings partly explain why drugs designed to treat cancer by strangling its blood supply have been disappointing when used alone and why those treatments are more effective when combined with traditional chemotherapy.

Despite their rapid progression, tumors fed by more normal vascular were also more vulnerable to the effects of standard chemotherapy drugs, the team reports in this week’s early online edition of the journal Nature.

Nascent tumors take off as new blood vessels invade, an event called angiogenesis that many see as key to the development of malignancy. But those pathological vessels form tangled structures that are far from normal.

“Tumor blood vessels become more chaotic, disorganized and leaky,” said Randall S. Johnson, professor of molecular biology at UC San Diego who led the study. “They become dysfunctional in many ways as a blood vessel network.”

Cellular secretions within tumors promote the invasion. The first drugs designed to curtail cancer’s blood supply targeted one of these, called VEGF for vascular endothelial growth factor. Inflammatory cells, which infiltrate many types of tumors, provide one source of VEGF.

Johnson’s team created a strain of mice in which most inflammatory cells were missing the gene for VEGF, then cross-bred them with a strain that reliably develops mammary tumors and is commonly used to study breast cancer.

“The blood vessels look more organized and less leaky in the engineered mice,” said Christian Stockmann, a molecular biology postdoctoral fellow and the first author of the paper.

The blood supply to tumors in these mice was also sparse compared to mice with intact VEGF genes.

“A lot of these classic hallmarks of tumor blood vessels disappeared when the inflammatory cells couldn’t make VEGF,” Johnson said.

But the cancer grew faster.

All of the mice developed tumors, but at 20 weeks of age, those with low levels of VEGF from inflammatory cells had larger growths that were more likely to have progressed to a later stage of cancer.

“The tumors seemed much happier when they didn’t have this chaotic vasculature,” Johnson said.

The scientists also injected a cancerous cell line into normal and engineered mice and found that the introduced cells invaded normal tissues more readily without VEGF from inflammatory cells and developed more normal blood supplies.

The tumors that formed were also more susceptible to two different chemotherapy drugs in the mice lacking VEGF from inflammatory cells.

By identifying the cellular source of the critical factor for one pathology associated with cancer, the researchers say their findings may open new avenues for treatment.

The National Institutes of Health funded the research.


Story Source:

The above story is based on materials provided by University of California - San Diego. The original article was written by Susan Brown. Note: Materials may be edited for content and length.


Cite This Page:

University of California - San Diego. "Tumors Grow Faster Without Blood-supply Promoting Molecule." ScienceDaily. ScienceDaily, 12 November 2008. <www.sciencedaily.com/releases/2008/11/081110112156.htm>.
University of California - San Diego. (2008, November 12). Tumors Grow Faster Without Blood-supply Promoting Molecule. ScienceDaily. Retrieved September 17, 2014 from www.sciencedaily.com/releases/2008/11/081110112156.htm
University of California - San Diego. "Tumors Grow Faster Without Blood-supply Promoting Molecule." ScienceDaily. www.sciencedaily.com/releases/2008/11/081110112156.htm (accessed September 17, 2014).

Share This



More Health & Medicine News

Wednesday, September 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

President To Send 3,000 Military Personnel To Fight Ebola

President To Send 3,000 Military Personnel To Fight Ebola

Newsy (Sep. 16, 2014) President Obama is expected to send 3,000 troops to West Africa as part of the effort to contain Ebola's spread. Video provided by Newsy
Powered by NewsLook.com
Obama Orders Military Response to Ebola

Obama Orders Military Response to Ebola

AP (Sep. 16, 2014) Calling the Ebola outbreak in West Africa a potential threat to global security, President Barack Obama is ordering 3,000 U.S. military personnel to the stricken region amid worries that the outbreak is spiraling out of control. (Sept. 16) Video provided by AP
Powered by NewsLook.com
UN: 20,000 Could Be Infected With Ebola by Year End

UN: 20,000 Could Be Infected With Ebola by Year End

AFP (Sep. 16, 2014) Nearly $1.0 billion dollars is needed to fight the Ebola outbreak raging in west Africa, the United Nations say, warning that 20,000 could be infected by year end. Duration: 00:40 Video provided by AFP
Powered by NewsLook.com
Obama: Ebola Outbreak Threat to Global Security

Obama: Ebola Outbreak Threat to Global Security

AP (Sep. 16, 2014) President Obama is ordering U.S. military personnel to West Africa to deal with the Ebola outbreak, which is he calls a potential threat to global security. (Sept. 16) Video provided by AP
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