Marijuana Compounds Can Kill Some Cancer Cells: Study
A scientist in the United Kingdom has found that compounds derived from
marijuana can kill cancerous cells found in people with leukemia, a form of
cancer that is expected to cause an estimated 24,000 deaths in the United States
"Cannabinoids have a complex action; it hits a number of important
processes that cancers need to survive," study author Dr. Wai Liu, an
oncologist at the University of London's St. George medical school, told The
Huffington Post. "For that reason, it has really good potential over other
drugs that only have one function. I am impressed by its activity profile, and
feel it has a great future, especially if used with standard
Liu's study was recently published in the journal Anticancer Research. It was
supported by funding from GW Pharmaceuticals, which already makes a
cannabis-derived drug used to treat spasticity caused by multiple sclerosis.
The study looked at the effects of six different non-psychoactive
cannabinoids -- compounds derived from marijuana that do not cause the
"high" associated with its THC ingredient -- when applied alone, and
in combination, to leukemia cells. Cannabinoids displayed a "diverse range
of therapeutic qualities" that "target and switch off" pathways
that allow cancers to grow, Liu told U.S. News & World Report.
In an interview with The Huffington Post, Liu stressed that that his research
was built around the testing of the six purified cannabinoid forms -- not
traditional cannabis oil, which Liu described as "crude" in comparison
and generally containing 80-100 different cannabinoids. "We do not really
know which are the ones that will be anticancer and those that may be
harmful," Liu said.
During the study, Liu and his team grew leukemia cells in a lab and cultured
them with increasing doses of the six pure cannabinoids, both individually and
in combination with each other. His study says the six cannabinoids were CBD (Cannabidiol),
CBDA (Cannabidiolic acid), CBG (Cannbigerol), CBGA (Cannabigerolic acid), CBGV (Cannabigevarin)
and CBGVA (Cannabigevaric acid). Liu and his team then assessed the viability of
the leukemia cells and determined whether or not the cannabinoids destroyed the
cells or stopped them from growing.
Although promising, Liu also said that it remains unclear if the cannabinoid
treatment would work on the 200-plus existing types of cancer.
"Cancer is an umbrella term for a range of diseases that fundamentally
differ in their cellular makeup, [and] which occur as a result of disturbances
to growth controls," Liu said. "Chemotherapy works by disrupting these
dysfunctional growth signals. Therefore, any cancers that have these profiles
should respond to the chemotherapy. It just so happens that a number of
cannabinoids can target these very same mechanisms that make cancer what it is,
and so any cancer that exhibits these faults should respond well to
cannabinoids. The flip side is, of course, that other cancers may not have these
same genetic faults and so cannabinoids may not work as well."
According to the Centers for Disease Control, 7.6 million people die from
various forms of cancer each year worldwide.
When asked if smoking marijuana has the same or similar effects as ingesting
the pure cannabinoid compounds he studied, Liu said he thinks it's unlikely.
"Smoking cannabis introduces a number of potential problems," Liu
said. "First, the complex makeup of cannabis that contains about 80
bioactive substances means that the desired anticancer effect may be lost
because these compounds may interfere with each other. Second, we see that
delivering the drug either by injection or by a tablet would ensure the most
effective doses are given. Smoking would be variable, and indeed the heat of the
burning may actually destroy the useful nature of the compounds."
In 2012, researchers at the California Pacific Medical Center in San
Francisco found that CBD (cannbidiol), a non-toxic, non-psychoactive chemical
compound found in the cannabis plant, could stop metastasis in many kinds of
The National Cancer Institute has also funded some research into cannabis and
cancer, including a 2012 study that looked at the effects cannabis compounds
have on slowing the progression of breast cancer, spokesman Michael Miller told
U.S. News and World Report. However NCI has not funded research on the effects
of cannabinoids on leukemia.
Liu stressed that much work is still needed, and said that finding support
for marijuana-derived medicines can be polarizing.
"Although there is much promise, I struggle to find enough support to
drive this work on," Liu said. "The mention of cannabinoids can
polarize the public, who understandably link cannabis smoking with
Liu told the Seattle PI's Pot Blog that he hopes to start clinical trials
involving humans in 12 to 18 months.