Marijuana Compound May Fight Lung Cancer

By Amanda Gardner
HealthDay Reporter 17 minutes ago


TUESDAY, April 17 (HealthDay News) -- While smoking marijuana is never
good for the lungs, the active ingredient in pot may help fight lung
cancer, new research shows.

Harvard University researchers have found that, in both laboratory and
mouse studies, delta-tetrahydrocannabinol (THC) cuts tumor growth in
half in common lung cancer while impeding the cancer's ability to spread.

The compound "seems to have a suppressive effect on certain lines of
cancer cells," explained Dr. Len Horovitz, a pulmonary specialist at
Lenox Hill Hospital in New York City.

According to the researchers, THC fights lung cancer by curbing
epidermal growth factor (EGF), a molecule that promotes the growth and
spread of particularly aggressive non-small cell lung cancers. "It
seems to go to (EGF) receptor sites on cells and inhibit growth," said
Horovitz, who was not involved in the study.

The findings are preliminary, however, and other outside experts urged
caution.

"It's an interesting laboratory study (but) you have to have enough
additional animal studies to make sure the effect is reproducible and
to make sure that there are no overt toxic effects," said Dr. Norman
Edelman, chief medical officer of the American Lung Association. "It's
a little more than tantalizing because it's a compound that we know
has been in humans and has not caused major problems."

The findings were to be presented this week at the annual meeting of
the American Association for Cancer Research (AACR) in Los Angeles.

Lung cancer is the number one cancer killer in the world. Lung tumors
that over-produce the EGF receptor tend to be extra-aggressive and
don't respond well to chemotherapy.

THC is the main active ingredient of Cannabis sativa --marijuana. It
has been shown to inhibit tumor growth in cancer, but specific
information on its action against lung cancer has so far been limited.

In the new study, the researchers first showed that two different lung
cancer lines, as well as samples from patient lung tumors, produced
the cannabinoid receptors CB1 and CB2.

Endocannabinoids -- cannabinoids produced naturally in the body -- are
thought to have an effect on pain, anxiety and inflammation when they
bind to cannabinoid receptors.

Next, the researchers injected standard doses of THC into mice
implanted with human lung cancer cells. After three weeks of
treatment, tumors shrank by about 50 percent in animals treated with
THC, compared to those in an untreated control group, the researchers
reported.

The findings may shed light on a question that has been puzzling
Horovitz: Why hasn't there been a spike in lung cancer in the
generation that smoked a lot of marijuana in the 1960s.

"I find it fascinating, wondering if the reasons we're not seeing this
spike is that THC inhibits lung cancer cells," he said. "It would be
very ironic, although you certainly wouldn't tell somebody who smoked
cigarettes to add marijuana."

A second set of findings presented at AACR suggested that a
viral-based gene therapy could target both primary and distant tumors,
while ignoring healthy cells.

When injected into 15 mice with prostate cancer, this "smart bomb"
therapy eliminated all signs of cancer -- effectively curing the
rodents. Researchers at Columbia University, in New York City, said
the therapy also worked in animals with breast cancer and melanomas.

And in a third hopeful trial reported at the meeting, German
researchers at University Children's Hospital, in Ulm, said they've
used measles viruses to treat brain tumors. In mouse experiments, the
virus attached to the tumor from the inside out, the team said.

More information

For more on lung cancer, head to the American Lung Association.

http://news.yahoo.com/s/hsn/20070417/hl_hsn/marijuanacompoundmayfightlungcancer