The American Association for Cancer Research presented the results of a study carried out at Harvard University in 2007 and this still remains the most comprehensive ever realised on THC’s potential to combat tumour growth.
The study indicated that THC has both anti-tumorigenic and anti-metastatic effects on lung cancer cells. The authors found that doses of THC were able to cut lung cancer tumour growth in murine subjects in half in just three weeks and to reduce cancer lesions by even more.
THC, that targets cannabinoid receptors CB1 and CB2, is similar in function to the endocannabinoids which are naturally produced in the body and activates these receptors. The researchers suggest that THC and other “designer agents “ that activate these receptors might be used in a targeted fashion to treat lung cancer.
“The beauty of this study is that we are showing that a substance of abuse, if used prudently, may offer a new road to therapy against lung cancer,” commented Anju Preet, Ph.D., a researcher in the Division of Experimental Medicine at the university.
Acting through cannabinoid receptors CB1 and CB2, endocannabinoids (as well as THC) are thought to play a role in variety of biological functions, including pain and anxiety control as well as the modification of inflammatory processes.
In the present study, the researchers first demonstrated that two different lung cancer cell lines as well as patient lung tumour samples have CB1 and CB2 receptors on the surface of the cells, and that non-toxic doses of THC inhibited growth and spread in the cell lines.
Lung cancers that over-express EGFR are usually highly aggressive and resistant to chemotherapy treatments. “When the cells are pre-treated with THC, they have less EGFR-stimulated invasion as measured by various in-vitro assays,” Preet said in 2007.
Why 13 years later on has so little attention been given to this potentially revolutionary therapeutic?
Pascalbiosciences, an American pharmaceutical company, seems to think there is money in such research.
Researchers injected standard doses of THC during three weeks into mice that had been implanted with human lung cancer cells and found that tumours were reduced in size and weight by about 50 percent in the treated animals compared to a control group. Additionally there was a 60 percent reduction in cancer lesions on the lungs of these mice as well as a significant reduction in protein markers associated with cancer progression.
Although the researchers do not know why THC inhibits tumour growth, they hypothesise that it could be activating molecules that can arrest the cell cycle. They speculate that THC may also interfere with both angiogenesis, a process through which new blood vessels form from pre-existing vessels, and vascularisation, which is often deemed the holy grail of tissue engineering because it is one of the key preconditions that determine the in-vivo viability of tissue constructs. Both these processes promote cancer growth and by disrupting them THC slows the growth of the cancer down to such an extent that it is no longer being supplied with the requisite growth conditions.
More work is needed to clarify the mechanism by which THC functions, and on a cautionary note other unrelated animal studies have shown that THC can stimulate the growth of some cancers and in particular hormone-driven breast cancers .
THC offers significant promise, but there is a long way to go before its full potential can be identified and then realised.
The research was presented at the 2007 meeting of the American Association for Cancer Research, held Apr 14-18, 2007 in Los Angeles, CA. Why 13 years later on has so little attention been given to this potentially revolutionary therapeutic?
Pascalbiosciences, an American pharmaceutical company, seems to think there is money in such research: