Bio Saga Blog - A Chronicle of Life Sciences & Informatics

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...

By activating a cancer suppressor gene, a small molecule called nutlin-3a can block cancer cell division, according to researchers at the National Cancer Institute (NCI), part of the National Institutes of Health. This activation of the p53 gene leads to cellular senescence. An opportunity for new genetic mutations occurs each time a cell divides, so limiting the number of cell divisions in a cancer cell inhibits tumor progression. Activation of p53 can suppress tumor growth through more than one mechanism. It can interfere with the cell cycle, prompting a cell with unrepaired DNA damage to commit suicide through a complex signaling pathway called apoptosis. Alternatively, p53 may trigger cellular senescence in response to DNA damage or cellular stress. The expression of p53 is regulated by Mdm2, a protein that is overexpressed in several human cancers. Nutlins are small-molecule ...