The compounds in cannabis are already known to alleviate the pain from cancer and other illnesses, but now some studies have found that cannabis may also stop tumor cells from growing and getting out of control, as normally happens in untreated cancer.
In one of the latest studies, researchers Robert Ramer and Burkhard Hinz from the Institute of Toxicology and Pharmacology at the University of Rostock in Germany have found that cannabinoid compounds, such as tetrahydrocannabinol (THC) and methanandamide (MA), can cause the regression of highly invasive cancers, including cervical cancer and lung carcinoma.
Previous studies (as far back as the ‘70s) have shown that cannabinoids can also inhibit tumor cell growth in cancers such as lung adenocarcinomas, gliomas, thyroid epitheliomas, lymphomas, and skin carcinomas. However, the underlying cellular mechanisms are not currently known.
In the current study, Ramer and Hinz performed an in vitro study on the cervical cancer cell line HeLa, and found that in vitro HeLa cells incubated with small amounts (oral doses) of THC or MA showed diminished cancer cell invasion through a cell membrane after 24 hours. After 72 hours, they found that cancer cell invasiveness was diminished by up to 68% with THC treatment and 62% with MA treatment.
The researchers suspect that, to inhibit tumor cell growth, THC and MA likely inhibit several cell signaling pathways. Specifically, the cannabinoids stimulate the expression of the tissue inhibitor called TIMP-2. In turn, an increase of TIMP-2 can suppress tumor growth and angiogenesis (when tumors form new blood vessels). The scientists also identified other enzymes that the chemicals impact before triggering TIMP-2, and suggest the pathway could be more complex.
However, the scientists also discovered that toxic effects occurred when a small density of tumor cells was treated with either of the cannabinoids. According to the researchers' knowledge, this is the first finding of density-dependent cannabinoid toxicity. However, density-dependent toxicity is widely known to exist in several chemotherapeutics used to treat cancer. Scientists also know that both THC and MA can cause receptor-independent apoptosis, a type of cell death.
The researchers plan to do further studies to investigate how in vivo tumors respond to THC and MA. They also hope to find what types of cancers, in addition to cervical and lung carcinoma, might benefit from the new treatment.
via: Journal of the National Cancer Institute