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Show U cancer research Findings reveal key control The presence of a control mechanism found in normal cells but apparently missing or defective defec-tive in cancer cells has been discovered dis-covered by a University scientist working in a Veterans Administration Admini-stration Hospital laboratory here. "We don't yet know what the mechanism is or how it works, but our findings suggest a biochemical difference between normal and cancer cells," says Dr. Frank J. O'Neill, assistant professor of microbiology and pathology at the University. "Determining the biochemical components of the mechanism could be the forerunner to the development of anti-cancer drugs." Dr. O'Neill emphasizes that his discovery offers no hope to patients currently suffering from cancer. "But it opens a new avenue of approach in cancer research," he says. "Previously cancer has been extensively studied only biologically and histologically-not biochemically." biochem-ically." The University researcher has determined that an unknown mechanism which appears to check chromosome pulverization is present in normal, healthy human cells. Chromosome pulverization is an abnormality which occurs occasionally in blood and epithelial cancers. In cells with two or more nuclei, the nucleus that divides first "pushes" adjoining nuclei to divide. If they are not ripe for division, their chromosomes become pulverized. To find out what happens when the cells' cytoplasm is purposely kept from dividing, Dr. O'Neill and his research assistants added a chemical called Cytochalasin B to both normal and cancer cells, which prevents cytoplasmic division but still allows the nuclei to split. When Cytochalasin B was added to cancerous cells in humans, hamsters and mice, chromosome pulverization occurred oc-curred and the nuclei divided numerous times. In normal cells, the nuclei divided only once, sometimes twice, and there was no pulverization. "The results suggest that there is a mechanism in normal cells that controls nuclear division says Professor O'Neill. If the mechanism can now be isolated, it will give us a molecular basis for determining the precise defect in cancer cells and why they have unlimited growth." The University scientist, who has been working on this particular par-ticular project since 1968 and has been engaged in cancer research for eight years, plans several studies to determine the properties of the control. They will then fuse a benign cell with a cancer cell to see which type of nucleus dominates. "If the normal nucleus dominates, it will expedite our search for the control mechanism and help us activate it in cancer cells to curtail their growth," he says. "Chromosomes are often lost in fused cells, so that the hybrid cell contains only one or two chormosomes from one of the parental cells," he adds. "If this happens, and the cancer nucleus is dominant, we may be able to pinpoint the cancer-carrying chromosome. For instance, if the human chromosome 1 contains the cancer-carrying information, then only those hybrids with this element will show the defective control mechanism. Hybrids with any of the other chromosomes but without n will appear normal." |