The Suicide of Cancer Cells
Scientists from the University of Nijmegen have discovered that some cancer cells 'commit suicide' when exposed to radical treatment. This "kamikaze" phenomenon is also of great interest because the mechanisms that cause the destruction of genetically damaged cells are often disabled in the cancer cells. The results of the study may reveal new ways to effectively treat certain types of cancer with chemotherapy. A wide range of substances from the diet act permanently on the intestinal epithelium. Some of these components also generate aggressive free radicals. The cells of the epithelium use different ways to neutralize the free radicals. Sometimes, however, these defense mechanisms do not work. The researchers from the University of Nijmegen specifically studied the human colon cancer cell line Caco-2, as this cell type goes through the entire cycle from germ cell to functional cell.
When such cells were exposed to a low dose (25 micromolar) of substances that produce free radicals, about 20 percent "committed suicide". More detailed investigations showed that in the cell line Caco-2 the p53 gene - an important gene in the self-destruction of cells - is damaged. But even undamaged cells that were only slightly attacked by the radicals destroyed themselves. These cells were characterized by a greatly reduced glutathione level. Glutathione exerts a protective function against free radicals.
Scientists assume that the balance between phosphorylation and dephosphorylation of the proteins involved in cell division is disturbed. In their opinion, it shifts in the direction of phosphorylation. It is possible that exposure to the radicals forces cells to divide at a time when they are not yet ready. Premature division interrupts further cell metabolism and leads to self-destruction.
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