Marijuana May Fight Lung Tumors

[Miasma]

Marihuana voi estää keuhkokasvaimien kasvua

Cannabis may be bad for the lungs, but the active ingredient in marijuana may help combat lung cancer, new research suggests.

In lab and mouse studies, the compound, known as THC, cut lung tumor growth in half and helped prevent the cancer from spreading, says Anju Preet, PhD, a Harvard University researcher in Boston who tested the chemical.

While a lot more work needs to be done, the results suggest THC has therapeutic potential, she tells WebMD.

Moreover, other early research suggests the cannabis compound could help fight brain, prostate, and skin cancers as well, Preet says.

The findings were presented at the annual meeting of the American Association for Cancer Research.

The finding builds on the recent discovery of the body's own cannabinoid system, Preet says. Known as endocannabinoids, the natural cannabinoids stimulate appetite and control pain and inflammation.

THC seeks out, attaches to, and activates two specific endocannabinoids that are present in high amounts on lung cancer cells, Preet says. This revs up their natural anti-inflammatory properties. Inflammation can promote the growth and spread of cancer.

In the new study, the researchers first demonstrated that THC inhibited the growth and spread of cells from two different lung cancer cell lines and from patient lung tumors. Then, they injected THC into mice that had been implanted with human lung cancer cells. After three weeks, tumors shrank by about 50 percent, compared with tumors in untreated mice.

Preet notes that animals injected with THC seem to get high, showing signs of clumsiness and getting the munchies. You would expect to see the same thing in humans, so if this work does pan out, getting the dose right is going to be all important, she says.

Paul B. Fisher, PhD, a professor of clinical pathology at Columbia University, says that though the work is interesting, it's still very early.

The issue with using a drug of this type becomes the window of
concentration that will be effective. Can you physiologically achieve what you want without causing unwanted effects, he tells WebMD.

By Charlene Laino
Reviewed by Louise Chang
©2007 WebMD, Inc. All rights reserved.

http://www.cbsnews.com/stories/2007/04/ ... 6726.shtml

Marijuana Stops Growth of Lung Cancer Tumors in Mice (Update1)

By Angela Zimm

April 17 (Bloomberg) -- Giving marijuana to mice with cancer shrank their lung tumors by half and slowed spread of the disease, findings that may one day expand legal use of the substance as a treatment, researchers said.

The research is the first to show that marijuana's active ingredient, tetrahydrocannabinol, or THC, blocks a known cancer- related protein that's already the target of drugs such as ImClone System Inc.'s Erbitux and Amgen Inc.'s Vectibix.

The findings, presented today at the American Association for Cancer Research meeting in Los Angeles, add to evidence that marijuana may have anti-tumor properties and its potential should be probed further, researchers said. Scientists speculate THC may activate biological pathways that halt cancer cell division or block development of blood vessels that feed tumors.

``THC can have a potential therapeutic role,'' said Anju Preet, the study's lead author and a researcher at Harvard University's division of experimental medicine. ``Maybe THC is killing cells. The preliminary studies are promising.''

Tumor cells dosed with THC also showed a reduction in epidermal growth factor receptor, or EGFR, which means the substance may be acting in ways similar to Erbitux and Vectibix, which block the protein, Preet said.

The group includes Erbitux, which treats colon and head and neck cancers, Vectibix, which treats colon cancer, Genentech Inc.'s Tarceva, approved for lung and pancreatic cancer, and AstraZeneca Plc's Iressa, which treats lung cancer.

Lung cancer cells with high levels of EGFR are generally very aggressive and treatment resistant, researchers said.

Receptors

THC activates ``cannabinoid receptors,'' which are proteins found in the brain and other parts of the body that are involved in a number of biological functions, including inflammation and pain. Researchers set out to see if they could inhibit tumor growth by targeting these receptors in both human lung tumor samples and in mice.

In addition to reducing tumor size by half, THC was also associated with a 60 percent reduction in cancer lesions in the lungs of mice.

A British study of nine brain-tumor patients last year found THC reduced growth of cancer cells, and other tests suggest it has potential in skin and breast cancers, Preet said.

More work needs to be done to understand how THC prevents tumor growth and to find the right dose before starting clinical trials, Preet said. Previous research has shown that too much THC can stimulate cancer growth, she said.

``Before jumping into clinical study we need to understand how it works, which can help us design a better therapeutic,'' Preet said.

In the U.S., 11 states have enacted laws that allow patients to use marijuana for medical purposes. The states are Alaska, California, Colorado, Maine, Montana, Nevada, Oregon, Washington, Hawaii, Vermont and Rhode Island, according to the Marijuana Policy Project, a marijuana policy reform organization based in Washington D.C. Last month, Bill Richardson, the governor of New Mexico, signed a bill that would make his state the 12th to legalize marijuana for medical use.

Only one THC drug, called Marinol, is approved in the U.S. The treatment, made by Solvay Pharmaceuticals, is used as an appetite stimulant for cancer patients.

http://www.bloomberg.com/apps/news?pid= ... healthcare