A particularly deadly form of brain cancer may be warded off by a combination of compounds in marijuana, preliminary research suggests.
Researchers at the California Pacific Medical Center Research Institute (CPMCRI) combined the non-psychoactive Cannabis compound, cannabidiol (CBD), with 9-tetrahyrdocannabinol (9-THC), the primary psychoactive active ingredient in Cannabis.
They found the combination boosts the inhibitory effects of 9-THC on glioblastoma, the most common and aggressive form of brain tumor.
"Our study not only suggests that combining these two compounds creates a synergistic effect but it also helps identify molecular mechanisms at work here, and that may lead to more effective treatments for glioblastoma and potentially other aggressive cancers," said Sean McAllister, a scientist at CPMCRI and the lead author of the study.
Previous studies had shown that 9-THC was effective in inhibiting brain cancer growth in cell cultures and in animal models and prompted a small clinical trial in Spain.
There is also evidence that other compounds in Cannabis might prove effective against tumors, but limited scientific evidence is available.
The CPMCRI researchers screened a number of different cannabis-based compounds before settling on CBD as the most active one.
"Compared to using 9-THC alone against glioblastoma cell lines, the combination therapy of 9-THC and CBD showed a significant improvement in activity, both in slowing down the growth of those cells and also, and perhaps more importantly, in doubling the number of cancer cells which underwent apoptosis or programmed cell death," McAllister said.
The new study has been published in the latest issue of the journal Molecular Cancer Therapeutics.