Featured Research

from universities, journals, and other organizations

New Strategy For Normalizing Tumor Blood Supply Identified

Date:
February 21, 2008
Source:
Massachusetts General Hospital
Summary:
Manipulating levels of nitric oxide, a gas involved in many biological processes, may improve the disorganized network of blood vessels supplying tumors, potentially improving the effectiveness of radiation and chemotherapy.

Manipulating levels of nitric oxide (NO), a gas involved in many biological processes, may improve the disorganized network of blood vessels supplying tumors, potentially improving the effectiveness of radiation and chemotherapy. In an upcoming issue of the journal Nature Medicine, researchers from the Steele Laboratory of Radiation Oncology at Massachusetts General Hospital (MGH) report an experiment in which NO production was selectively suppressed in tumor cells while being maintained in blood vessels. The result was a significant improvement in the appearance and function of the tumor's blood supply.

"Our finding suggest that the creation of perivascular NO gradients -- differences between the levels produced in blood vessels and those found in tumor tissue -- may be able to normalize tumor vasculature," says Dai Fukumura, MD, PhD, of the Steele Laboratory, who led the study. "Combining the use of angiogenesis inhibitors, which normalize vasculature through a different mechanism, with the blockade of nonvascular NO production may produce even greater improvement in therapeutic outcomes."

The blood vessels that develop around and within tumors are leaky and disorganized, interfering with delivery of chemotherapy drugs and with radiation treatment, which requires an adequate oxygen supply. Combining angiogenesis inhibitors, drugs that suppress the growth of blood vessels, with traditional anticancer therapies has improved patient survival in some tumors. That success supports a theory developed by Rakesh K. Jain, PhD, director of the Steele Laboratory, that the agents temporarily 'normalize' blood vessels, creating a period during which other treatments can be more effective.

Since angiogenesis is one of many physiologic activities mediated by NO, the MGH research team hypothesized that restricting NO production to blood vessels also could improve tumor vasculature. Using cancer cells from human brain tumors, they suppressed the enzyme that controls NO production in nonvascular tissue. When the modified tumor cells were implanted into mice, analysis of the resulting tumors showed that NO was present primarily in blood vessels, with significant reductions in tumor cells. Vessels in the growing tumors were more evenly distributed and less distorted than those in tumors grown from untreated tissue.

"Angiogenesis inhibitors block formation of new vessels by directly or indirectly inhibiting the proliferation and survival of vascular endothelial cells. But since their overall effect is to reduce the density of blood vessels, the ability of those agents to normalize tumor vasculature may not last long," says Fukumura. "Blocking nonvascular NO production and maintaining NO levels around the vessels appears to keep endothelial cell function at the proper level." An associate professor of Radiation Oncology at Harvard Medical School, Fukumura notes that the strategy now should be investigated in other types of tumors.

The Nature Medicine report has been released online and was supported by grants from the National Cancer Institute. In addition to Fukumura and Jain, co-authors of the article are first author Satoshi Kashiwagi, MD, PhD, Kosuke Tsukada, PhD, Lei Xu, MD, PhD, Junichi Miyazaki, MD, PhD, Sergey Kozin, DSc, PhD, James Tyrrell, PhD, and Leo Gerweck, PhD, all of the Steele Lab; and William Sessa, PhD, Yale University School of Medicine.


Story Source:

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


Cite This Page:

Massachusetts General Hospital. "New Strategy For Normalizing Tumor Blood Supply Identified." ScienceDaily. ScienceDaily, 21 February 2008. <www.sciencedaily.com/releases/2008/02/080220110320.htm>.
Massachusetts General Hospital. (2008, February 21). New Strategy For Normalizing Tumor Blood Supply Identified. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2008/02/080220110320.htm
Massachusetts General Hospital. "New Strategy For Normalizing Tumor Blood Supply Identified." ScienceDaily. www.sciencedaily.com/releases/2008/02/080220110320.htm (accessed July 29, 2014).

Share This




More Health & Medicine News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deadly Ebola Virus Threatens West Africa

Deadly Ebola Virus Threatens West Africa

AP (July 28, 2014) West African nations and international health organizations are working to contain the largest Ebola outbreak in history. It's one of the deadliest diseases known to man, but the CDC says it's unlikely to spread in the U.S. (July 28) Video provided by AP
Powered by NewsLook.com
$15B Deal on Vets' Health Care Reached

$15B Deal on Vets' Health Care Reached

AP (July 28, 2014) A bipartisan deal to improve veterans health care would authorize at least $15 billion in emergency spending to fix a veterans program scandalized by long patient wait times and falsified records. (July 28) Video provided by AP
Powered by NewsLook.com
Two Americans Contract Ebola in Liberia

Two Americans Contract Ebola in Liberia

Reuters - US Online Video (July 28, 2014) Two American aid workers in Liberia test positive for Ebola while working to combat the deadliest outbreak of the virus ever. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) 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