Non-involvement of the K-ras mutation in colon carcinogenesis promoted by dietary deoxycholate in azoxymethane-treated rats.
Fisher-344 rats, whose ileum or jejunum had been surgically removed to change the influx of bile acids into the colon, were intraperitoneally administered with azoxymethane and fed on a diet containing deoxycholate for 39 weeks to induce colon cancer. Fecal bile acids in the ileum-resected group were 1.5-times and serum bile acids were about half of those in the jejunum-resected group. As a result, the incidence and number of tumors were higher in the ileum-resected group. In the total of 59 colon tumors (40 were in the ileum-resected group and 19 in the jejunum-resected group), 56 were carcinomas, including two well-differentiated invasive and two mucinous carcinomas found in the ileum-resected rats. However, only three carcinomas, two invasive and one non-invasive, had the K-ras mutation. These results demonstrate that the K-ras mutation was not essentially involved in deoxycholate-promoted colon carcinogenesis.
Kanamoto
R
R
Department of Biological Resource Chemistry, Kyoto Prefectural University, Japan. kanamoto@kpu.ac.jp
Azuma
N
N
Tsuchihashi
Y
Y
Suda
H
H
Saeki
T
T
Iwami
K
K
D000818:Animals; D001397:Azoxymethane / Q000494:pharmacology*; D002273:Carcinogens / Q000494:pharmacology*; D002277:Carcinoma / Q000139:chemically induced* / Q000235:genetics* / Q000473:pathology; D003110:Colonic Neoplasms / Q000139:chemically induced* / Q000235:genetics* / Q000473:pathology; D003840:Deoxycholic Acid / Q000494:pharmacology*; D004032:Diet; D011905:Genes, ras / Q000235:genetics*; D009154:Mutation / Q000235:genetics; D018807:Polymorphism, Single-Stranded Conformational; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction
D002273:Carcinogens; D003840:Deoxycholic Acid; D001397:Azoxymethane