Premium
Ha‐ ras mutations in N ‐nitrosomorpholine‐induced lesions and inhibition of hepatocarcinogenesis by antisense sequences in rat liver
Author(s) -
Baba Miyako,
Yamamoto Reiko,
Iishi Hiroyasu,
Tatsuta Masaharu
Publication year - 1997
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/(sici)1097-0215(19970904)72:5<815::aid-ijc18>3.0.co;2-7
Subject(s) - oligonucleotide , sense (electronics) , oncogene , microbiology and biotechnology , biology , antisense therapy , fluorescein isothiocyanate , mutation , hepatocellular carcinoma , cancer research , messenger rna , cancer , gene , locked nucleic acid , chemistry , biochemistry , genetics , fluorescence , physics , quantum mechanics , cell cycle
To evaluate the application of Ha‐ ras mRNA antisense oligonucleotide therapy for liver tumors, we examined the frequency and types of mutation in codon 61 of the Ha‐ ras oncogene in preneoplastic lesions and hepatocellular carcinomas induced by N ‐nitrosomorpholine (NNM) in rats. Thirty‐seven percent of preneoplastic lesions and 50% of hepatocellular carcinomas contained mutations, mostly CAA‐CTA and CAA‐AAA transversions. We also investigated the effects on NNM‐induced lesions of an antisense oligonucleotide directed against a point mutation (CAA‐CTA) in codon 61 of Ha‐ ras mRNA. In this experiment, Sprague‐Dawley rats were given free access to water containing NNM for 8 weeks and received twice‐weekly i.p. injections of a mutated Ha‐ ras antisense oligonucleotide with a 5′ phosphorothioate linkage or a sense oligonucleotide in oligonucleotide‐liposome complexes. At week 16, rats that had received the mutated Ha‐ ras antisense oligonucleotides had significantly fewer and smaller preneoplastic lesions positive for glutathione‐S‐transferase, placental type, and had smaller hepatocellular carcinomas than rats that had received the sense oligonucleotide. Mean cellular fluorescence in the liver was found to increase with higher doses of mutated, fluorescein‐isothiocyanate‐labeled antisense or sense oligonucleotides. Moreover, mutated Ha‐ ras antisense oligonucleotide decreased the expression of mutated Ha‐ ras mRNA (CAA‐CTA). Our findings indicate that mutated Ha‐ ras antisense oligonucleotide significantly inhibits hepatocarcinogenesis in rats and could be an effective therapy against liver tumors. Int. J. Cancer 72:815–820, 1997. © 1997 Wiley‐Liss, Inc.