RT Journal Article
SR Electronic
T1 Characterization of the Effects Induced on DNA in Mouse and Hamster Cells by Lithocholic Acid
JF Cancer Research
JO Cancer Res
FD American Association for Cancer Research
SP 2866
OP 2874
VO 47
IS 11
A1 Russo, Patrizia
A1 Taningher, Maurizio
A1 Pala, Mauro
A1 Pisano, Viviana
A1 Pedemonte, Piera
A1 De Angeli, Maria Teresa
A1 Carlone, Sebastiano
A1 Santi, Leonardo
A1 Parodi, Silvio
YR 1987
UL http://cancerres.aacrjournals.org/content/47/11/2866.abstract
AB Lithocholic acid (LCA) is a promoting agent in colon carcinogenesis. In this work we have tried to characterize the DNA alteration induced by LCA in cells grown in vitro and in nuclei. Confirming previous findings, a clear increase in elution rate was observed at both alkaline and neutral pH. The extent of the increase was very similar at the two pHs. However, an increased elution rate could be observed only when lysing the nuclei at high ionic strength and low detergent concentration (2 m NaCl + 0.2% N-lauroylsarcosine sodium salt). No effect could be observed when the nuclei were lysed with a high detergent concentration (2% sodium dodecyl sulfate). In addition, a slight effect could be observed using a method for the evaluation of DNA unwinding in alkali. After termination of the incubation with LCA, the DNA alteration observed with DNA elution disappeared very rapidly both in intact cells and nuclei, even when the incubation buffer was totally unsuitable for the repair of the type of DNA damage induced by typical genotoxic agents. The effect of LCA on DNA was apparently not mediated through an inhibition of topoisomerase II. Only the intact chromatin of nuclei was responsive, not the quasinaked DNA of nuclei lysed at high ionic strength. We advance the hypothesis that the increased alkaline and neutral elution rate observed with LCA could be independent of DNA fragmentation and related to changes in chromatin structure. ©1987 American Association for Cancer Research.