In vivo measurement of DNA synthesis rates of colon epithelial cells in carcinogenesis.
We describe here a highly sensitive technique for measuring DNA synthesis rates of colon epithelial cells in vivo. Male SD rats were given (2)H(2)O (heavy water). Colon epithelial cells were isolated, DNA was extracted, hydrolyzed to deoxyribonucleosides, and the deuterium enrichment of the deoxyribose moiety was determined by gas chromatographic/mass spectrometry. Turnover time of colon crypts and the time for migration of cells from basal to top fraction of the crypts were measured. These data were consistent with cell cycle analysis and bromodeoxyuridine labeling. By giving different concentrations of a promoter, dose-dependent increases in DNA synthesis rates were detected, demonstrating the sensitivity of the method. Administration of a carcinogen increased DNA synthesis rates cell proliferation in all fractions of the crypt. In conclusion, DNA synthesis rates of colon epithelial cells can be measured directly in vivo using stable-isotope labeling. Potential applications in humans include use as a biomarker for cancer chemoprevention studies.
Kim
Sylvia Jeewon
SJ
Graduate Group in Molecular and Biochemical Nutrition, 309 Morgan Hall, University of California at Berkeley, CA 94720, USA.
Turner
Scott
S
Killion
Salena
S
Hellerstein
Marc K
MK
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D016588:Anticarcinogenic Agents / Q000494:pharmacology; D001241:Aspirin / Q000494:pharmacology; D001397:Azoxymethane / Q000494:pharmacology; D001834:Body Water / Q000737:chemistry; D001973:Bromodeoxyuridine / Q000032:analysis; D002453:Cell Cycle; D049109:Cell Proliferation; D019826:Cholic Acid / Q000008:administration & dosage / Q000494:pharmacology; D003106:Colon / Q000166:cytology*; D003110:Colonic Neoplasms / Q000209:etiology; D004247:DNA / Q000096:biosynthesis*; D003903:Deuterium / Q000032:analysis; D004847:Epithelial Cells / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D007700:Kinetics; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley
D000894:Anti-Inflammatory Agents, Non-Steroidal; D016588:Anticarcinogenic Agents; D004247:DNA; D003903:Deuterium; D019826:Cholic Acid; D001973:Bromodeoxyuridine; D001397:Azoxymethane; D001241:Aspirin