Turned-off Cannabinoid Receptor Turns On Colorectal Tumor Growth
New preclinical research shows that cannabinoid cell surface receptor CB1 plays a tumor-suppressing role in human colorectal cancer, scientists report in the Aug. 1 edition of the journal Cancer Research. Endocannabinoid signaling is important to the normal functioning of the digestive system and has been shown to protect the colon against inflammation. Since chronic inflammation is a known risk factor for colorectal cancer, the researchers decided to look into the role of cannabinoid receptors in a mouse model of colon cancer. Cannabinoids previously had been shown to kill cancer cells in lab experiments by inducing apoptosis - programmed cell death. The team confirmed the role of CB1 in apoptosis, showing that tumor cells with high CB1 expression were sensitive to apoptosis when treated by a cannabinoid agonist. Cell lines with silenced CB1 resisted cell death. A series of experiments showed that CB1 increases cancer cell death by stifling a protein called survivin. Survivin is ov...