Scientists Believe Marijuana Compound can Stop Metastasis in Certain Cancers

Illustration showing phrase medical marijuana with a pot leaf

Two researchers at the California Pacific Medical Center in San Francisco believe now that a chemical compound found in marijuana can be used to stop the metastasis of certain aggressive cancers.

They have confirmed their theory in both laboratory and animal testing. They are  awaiting approval to begin a clinical trial in humans.

Scientists Sean McAllister and Pierre Desprez believe the compound cannabidiol (CBD), found in the marijuana plant, has the potential to stop the spread of particular cancers. Their belief is based upon the findings that CBD has the ability to stop the expression of Id-1, a gene protein often responsible for the metastasis of cancers.

They first researched Id-1 in the laboratory involving breast cancer cells in 2007 and expanded their study more recently to include prostate and brain cancer. They have not done any research involving mesothelioma cancer, caused by exposure to asbestos fibers, but believe their findings could be beneficial there, also.

Could Work for Mesothelioma

“If the mesothelioma expressed Id-1, I expect CBD would inhibit tumor progression,” McAllister told Asbestos.com in an e-mail.

Medical uses for marijuana have expanded in recent years. They include helping to fight nausea, schizophrenia, convulsions and neurological disorders. Usage by cancer patients, including those with mesothelioma, has been limited mostly to palliative measures and pain management.

Although marijuana remains a prohibited substance by federal law, its medicinal use has been approved in almost half the states in America. Voters in Colorado will decide in November on Amendment 64, which would legalize and regulate marijuana like alcohol for adult use. If approved, Colorado would become the first state to legalize marijuana and other states likely would follow its lead.

Desprez, a molecular biologist, has been studying Id-1 for 20 years, and the way it spreads cancer, often through the lymphatic system or the bloodstream. McAllister has been studying the effects of CBD, the non-toxic chemical, for many years. It was their collaboration in San Francisco that prompted the findings.

“What we found was that his cannabidiol could essentially turn off the Id-1,” Desprez told the Huffington Post recently. “We’ve found that cannabidiol works with many kinds of aggressive cancers – brain, prostate – any kind in which these high levels of Id-1 are present.”

The presence of Id-1 with mesothelioma remains cloudy with limited research available on the topic. It may exist in some, but not all, mesothelioma tumors. There was one study in 2008, though,  published in the Journal of Cancer Research, that definitively linked malignant mesothelioma with Id-1.

For mesothelioma, the implication of the recent findings might not be as significant as with other cancers. Mesothelioma, which has a lengthy latency period (20 to 50 years) generally spreads locally and rarely metastasizes until very late in the process.

Awaiting Approval for Clinical Trial

Because CBD has been safely used with other ailments, Desprez and McAllister are hoping for quick approval to begin a clinical trial. They told the Huffington Post they already have begun synthesizing the cannabidiol in the lab to avoid any legal complications in getting a drug approved.

“We used injections in the animal testing, and are also using testing pills,” Desprez said. “You could never get enough cannabidiol for it to be effective just from smoking.”

Their 2007 study, using mice, concluded that CBD could stop the aggressive spreading of breast cancer cells to other parts of the body by blocking the expression of the Id-1 gene.

“CBD represents the first nontoxic exogenous agent that can significantly decrease Id-1 expression in metastatic breast cancer cells leading to the down-regulation of tumor aggressiveness,” they wrote in 2007.  “We report that CBD, a cannabinoid with a low toxicity profile, could down-regulate Id-1 expression in aggressive human breast cancer cells.”

Feds Still Fighting Medicinal Marijuana Use

Although the use of medicinal marijuana is becoming more prevalent – and the latest study certainly could intensify its importance – the federal government has continued its attempt to trample the rights of states that allow it.

In Los Angeles this week, federal prosecutors sued owners of three properties that were housing medicinal marijuana collectives and sent warning letters to 68 others shops that they were violating federal laws by staying open.

And while Desprez is excited about his latest findings, he also is well aware of the conflicting laws. Synthesizing the compound in a lab allows it to be more potent, but it also avoids any potential legal issues.

“It’s a common practice,” he said. “But hopefully, it will also keep us clear of any obstacles seeking approval.”


Tim Povtak is an award-winning writer with more than 30 years of reporting national and international news. His most recent experience is in researching and writing about asbestos litigation issues and asbestos-related conditions like mesothelioma. If you have a story idea for Tim, please email him at tpovtak@asbestos.com

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