Abstract
Geraniol and other monoterpenes found in essential oils of fruits and herbs have been suggested to represent a new class of agents for cancer chemoprevention. As a first step in clarifying the mode of action of geraniol on colon carcinogenesis, we studied its effects on the growth of a human colon cancer cell line (Caco-2). Geraniol (400 μM) caused a 70% inhibition of cell growth, with cells accumulating in the S transition phase of the cell cycle, and concomitant inhibition of DNA synthesis. No signs of cytotoxicity or apoptosis were detected. Geraniol caused a 50% decrease of ornithine decarboxylase activity, a key enzyme of polyamine biosynthesis, which is enhanced in cancer growth. This led to a 40% reduction of the intracellular pool of putrescine. Geraniol also activated the intracellular catabolism of polyamines, indicated by enhanced polyamine acetylation. These observations indicate that polyamine metabolism is presumably a target in the antiproliferative properties of geraniol.
Footnotes
- Abbreviations:
- DMEM
- Dulbecco's modified Eagle's medium
- AdoMetDC
- S-adenosylmethionine decarboxylase
- HMG-CoA
- 3-hydroxy-3-methylglutaryl-CoA
- ODC
- ornithine decarboxylase
- PBS
- phosphate-buffered saline
- FACS
- fluorescence-activated cell sorter
- Received January 25, 2001.
- Accepted March 9, 2001.
- The American Society for Pharmacology and Experimental Therapeutics
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