In the new study, researchers found that pharmacologic doses of chlorophyllin caused colon cancer cells to spend more time than normal in their "synthesis phase" in which DNA is duplicated. Timing is critical to the various phases of cell growth, researchers said, and this disruption started a process that ultimately led to cell death, the study found.
In particular, the presence of high levels of chlorophyllin caused a major reduction in the level of ribonucleotide reductase, an enzyme critical to DNA synthesis, researchers found. This is also the mechanism of action of hydroxyurea, one drug already being used for cancer chemotherapy.
"In cancer research right now there's interest in approaches that can reduce ribonucleotide reductase," Dashwood said. "At the doses used in our experiments, chlorophyllin almost completely stops the activity of this enzyme."
Further research is needed both in laboratory and animal studies, with combinations of chlorophyllin and existing cancer drugs, before it would be appropriate for human trials, Dashwood said. Chlorophyllin, in general, is poorly absorbed from the human gastrointestinal tract, so it's unclear what levels might be needed for therapeutic purposes or how well they would work.
Other dietary agents also might have similar potential. Work just published by LPI researchers in the journals Carcinogenesis and Cancer Prevention Research explored the role of organic selenium compounds in killing human prostate and colon cancer cells. Colorectal and prostate cancers are consistently among the leading causes of cancer mortality in the United States, and will account respecti
|Contact: Rod Dashwood|
Oregon State University