Study finds link between CB1 receptor and cancer cell growth

Aug 2, 2008 07:51 GMT  ·  By

According to a new study involving colon cancer, the development of the tumors could be stopped and even reversed with the help of a chemical usually found in marijuana, although the drug itself would need some additional chemical compounds in order to work. The discovery was made by researchers of the University of Texas, Houston, who found that in most human colon cancer cells the protein receptor for cannabinoids is turned off.

In the absence of this receptor, another protein, known as survivin, starts to grow in concentration, helping the cancer cells stay alive and allowing the tumor to grow uncontrollably. In order to show how the cannabinoid receptor influences the growth of the tumors, Raymond DuBois created an experiment in which mice were genetically altered to spontaneously develop colon cancers.

"When we knocked out the receptor, the number of tumors went up dramatically," says DuBois. However, when the mice having the cannabinoid receptor CB1, were given chemical compounds extracted from marijuana, the tumor reacted by reducing its size.

The results indicate that colon cancers as well as cancers that have their growth regulated by this receptor could be treated simply by turning on the CB1 receptor, only to be later activated with certain artificial cannabinoid compounds. The part related to the chemicals mimicking marijuana and switching the CB1 receptor back on is mostly solved, although it is not quite known if indeed in humans the cannabinoid compound would activate the receptor.

So far, the researchers know that the receptor could be blocked through a process known as methylation, at least in the case of human colon cancer cells. This is achieved through the alteration of the DNA code with the help of a small group of chemical compounds that can be removed by making use of a demethylating drug known as decitibine.