Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1990-1-10
pubmed:abstractText
There seems to be a current view that the inhibition of DNA methylation may be a mechanism of initiation of carcinogenesis or one of the steps required in the carcinogenic process. However, because of the deficiencies in research works on cellular level, there is a long way to make such a general relationship between carcinogen and the inhibition of cellular DNA methylation. In this paper the effects of some chemical carcinogens on methylation of newly replicated DNA in human FL cells was analyzed by comparing the weight average length (Lw) of the DNA digests after complete digestion by restriction endonuclease Hpa II. It was observed that two non-genotoxic carcinogens (5-azacytidine and L-ethionine) and two genotoxic carcinogens (MNNG and aflatoxin B1) used in this study all caused obvious cytotoxicity on FL cells at the test concentration. Five days after the termination of 5-azacytidine treatment (2 x 10(-6) M, 24 hours), Lw (kb) of the Hpa II digests of cellular DNA was smaller than that of control (8.0 +/- 0.1 vs 10.9 +/- 1.0, P less than 0.01), the Lw change rate was -27%. When DNA was analyzed from FL cells after 9 days continuous treatment of L-ethionine (2 x 10 M), the digestibility of Hpa II was also increased as compared with that of the control, the Lw values (kb) showed a decrease of about 8% (9.8 +/- 0.3 vs 10.6 +/- 0.3, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:language
chi
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0001-5334
pubmed:author
pubmed:issnType
Print
pubmed:volume
22
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
305-11
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
[Is hypomethylation of cellular DNA a step required in the initiation process of chemical carcinogenesis?].
pubmed:publicationType
Journal Article, English Abstract, Research Support, Non-U.S. Gov't