Featured Research

from universities, journals, and other organizations

Marijuana Component Opens The Door For Virus That Causes Kaposi's Sarcoma

Date:
August 2, 2007
Source:
American Association for Cancer Research
Summary:
The major active component of marijuana could aid the Kaposi's sarcoma virus in infecting cells and multiplying, according researchers at Harvard Medical School. They report that low doses of THC, equivalent to that in the bloodstream of an average marijuana smoker, could be enough to facilitate infection of skin cells and could even foster malignancy.

The major active component of marijuana could enhance the ability of the virus that causes Kaposi's sarcoma to infect cells and multiply, according to a team of researchers at Harvard Medical School. According to the researchers, low doses of -9 tetrahydrocannabinol (THC), equivalent to that in the bloodstream of an average marijuana smoker, could be enough to facilitate infection of skin cells and could even coax these cells into malignancy.

While most people are not at risk from Kaposi's sarcoma herpes virus (KSHV), researchers say those with lowered immune systems, such as AIDS patients or transplant recipients, are more susceptible to developing the sarcoma as a result of infection. Their findings, reported in the August 1 issue of Cancer Research, a journal of the American Association for Cancer Research, offer cautionary evidence that those with weakened immune systems should speak with their doctors before using marijuana medicinally or recreationally.

"These findings raise some serious questions about using marijuana, in any form, if you have a weakened immune system," said lead study author Jerome E. Groopman, M.D., professor of medicine at Harvard Medical School. "While THC is best known as the main psychotropic part of marijuana, an analog of THC is the active ingredient of marinol, a drug frequently given to AIDS patients, among others, for increasing appetite and limiting chemotherapy-induced nausea and vomiting."

While previous studies indicated that marijuana smoking was associated with Kaposi's sarcoma, this is the first to demonstrate that THC itself can assist the virus in entering endothelial cells, which comprise skin and related tissue.

According to Dr. Groopman, the study illustrates the complicated role marijuana and other cannabinoids play in human health. Numerous types of cells display cannabinoid receptors on their outer surfaces, which act as switches that control cellular processes. Dr. Groopman's laboratory had previously demonstrated that THC could have a protective effect against a certain form of invasive, drug-resistant lung cancer.

To study the combined effect of THC and KSHV, the researchers examined a culture of human skin cells, which are susceptible to infection and could provide a model of Kaposi's sarcoma. These culture cells display many copies of two prominent cannabinoid receptors. Dr. Groopman and his colleagues found that by bonding to these receptors, low doses of THC activate two proteins responsible for maintaining a cell's internal framework, or cytoskeleton.

By altering the cytoskeleton, THC effectively opens the door for KSHV, allowing the virus to more easily enter and infect the cell. "We can take away that effect by using antagonists that block the two cannabinoid receptors, which adds evidence that THC is the culprit," Dr. Groopman said.

Once a cell is infected, the presence of THC may also promote the cellular events that turn it cancerous, the researchers say. They found that THC also promotes the production of a viral receptor similar to one that attracts a cell-signaling protein called interleukin-8. Previous studies have noted that this receptor could trigger the cell to reproduce, causing Kaposi's sarcoma-like lesions in mice. Indeed, the researchers saw that THC induced the infected cells to reproduce and form colonies in culture.

"Here we see both infection and malignancy going on in the presence of THC, offering some serious concerns about the safety of THC among those at risk," Dr. Groopman said. "Of course, we still do not know the exact molecular events that are occurring here, but these results are just the first part of our ongoing research."

The study was funded by the National Institutes of Health.


Story Source:

The above story is based on materials provided by American Association for Cancer Research. Note: Materials may be edited for content and length.


Cite This Page:

American Association for Cancer Research. "Marijuana Component Opens The Door For Virus That Causes Kaposi's Sarcoma." ScienceDaily. ScienceDaily, 2 August 2007. <www.sciencedaily.com/releases/2007/08/070801112156.htm>.
American Association for Cancer Research. (2007, August 2). Marijuana Component Opens The Door For Virus That Causes Kaposi's Sarcoma. ScienceDaily. Retrieved September 1, 2014 from www.sciencedaily.com/releases/2007/08/070801112156.htm
American Association for Cancer Research. "Marijuana Component Opens The Door For Virus That Causes Kaposi's Sarcoma." ScienceDaily. www.sciencedaily.com/releases/2007/08/070801112156.htm (accessed September 1, 2014).

Share This




More Mind & Brain News

Monday, September 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Can You Train Your Brain To Eat Healthy?

Can You Train Your Brain To Eat Healthy?

Newsy (Sep. 1, 2014) New research says if you condition yourself to eat healthy foods, eventually you'll crave them instead of junk food. Video provided by Newsy
Powered by NewsLook.com
Coffee Then Napping: The (New) Key To Alertness

Coffee Then Napping: The (New) Key To Alertness

Newsy (Aug. 30, 2014) Researchers say having a cup of coffee then taking a nap is more effective than a nap or coffee alone. Video provided by Newsy
Powered by NewsLook.com
Young Entrepreneurs Get $100,000, If They Quit School

Young Entrepreneurs Get $100,000, If They Quit School

AFP (Aug. 29, 2014) Twenty college-age students are getting 100,000 dollars from a Silicon Valley leader and a chance to live in San Francisco in order to work on the start-up project of their dreams, but they have to quit school first. Duration: 02:20 Video provided by AFP
Powered by NewsLook.com
Baby Babbling Might Lead To Faster Language Development

Baby Babbling Might Lead To Faster Language Development

Newsy (Aug. 29, 2014) A new study suggests babies develop language skills more quickly if their parents imitate the babies' sounds and expressions and talk to them often. 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