Molecular analysis of carcinogen-induced rodent lung tumors: Involvement of microRNA expression and Krαs or Egfr mutations

  • Authors:
    • Keiko Yamakawa
    • Toshiya Kuno
    • Nozomi Hashimoto
    • Masanao Yokohira
    • Satoshi Suzuki
    • Yuko Nakano
    • Kousuke Saoo
    • Katsumi Imaida
  • View Affiliations

  • Published online on: January 1, 2010     https://doi.org/10.3892/mmr_00000231
  • Pages: 141-147
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Abstract

Genetic and epigenetic alterations play a key role in lung carcinogenesis, and a high frequency of KRAS and epidermal growth factor receptor (EGFR) mutations have been observed in human lung cancers. Recent evidence indicates that the expression of specific microRNAs (miRNAs) may be involved. In rodent lung carcinogenesis models, Kras mutations are frequently observed, whereas genetic alteration of the Egfr gene is generally rare. Since little is known regarding the involvement of miRNAs in rodent lung carcinogenesis, the present study of miRNA expression levels in the liver and lung during 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)- and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx)-induced lung tumorigenesis in A/J mice was conducted. In addition, incidences of Egfr and Kras gene mutations in rat and mouse lung tumors induced by the chemical carcinogens NNK, MeIQx and N-bis(2?hydroxypropyl)nitrosamine (DHPN) were examined. Three miRNAs, let-7a, miR-34c and miR-125a-5p, were selected for attention. In rat lung tumors, one silent mutation was detected in the Egfr gene exon 20 (AAC↷AAT; N772). Activating mutations of the Krαs gene at codon 12 were detected in neoplastic lesions induced by NNK (5/6, 83%), MeIQx (1/1, 100%) and DHPN (7/15, 47%), all resulting in G/C↷A/T transitions. NNK or MeIQx administration reduced the expression of miR-125a-5p (MeIQx alone group, 86.3%; MeIQx + NNK group, 83.6%; p<0.05, at day 15) and let-7a (MeIQx + NNK group, 56.3%; p<0.001, at day 22) in the liver. miR-34c was up-regulated 3.5-fold with NNK treatment as compared to the control group (p<0.001). These findings raise the possibility that aberrant expression of miRNA is involved in lung tumorigenesis, at least in its early stages.

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January-February 2010
Volume 3 Issue 1

Print ISSN: 1791-2997
Online ISSN:1791-3004

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Spandidos Publications style
Yamakawa K, Kuno T, Hashimoto N, Yokohira M, Suzuki S, Nakano Y, Saoo K and Imaida K: Molecular analysis of carcinogen-induced rodent lung tumors: Involvement of microRNA expression and Krαs or Egfr mutations . Mol Med Rep 3: 141-147, 2010
APA
Yamakawa, K., Kuno, T., Hashimoto, N., Yokohira, M., Suzuki, S., Nakano, Y. ... Imaida, K. (2010). Molecular analysis of carcinogen-induced rodent lung tumors: Involvement of microRNA expression and Krαs or Egfr mutations . Molecular Medicine Reports, 3, 141-147. https://doi.org/10.3892/mmr_00000231
MLA
Yamakawa, K., Kuno, T., Hashimoto, N., Yokohira, M., Suzuki, S., Nakano, Y., Saoo, K., Imaida, K."Molecular analysis of carcinogen-induced rodent lung tumors: Involvement of microRNA expression and Krαs or Egfr mutations ". Molecular Medicine Reports 3.1 (2010): 141-147.
Chicago
Yamakawa, K., Kuno, T., Hashimoto, N., Yokohira, M., Suzuki, S., Nakano, Y., Saoo, K., Imaida, K."Molecular analysis of carcinogen-induced rodent lung tumors: Involvement of microRNA expression and Krαs or Egfr mutations ". Molecular Medicine Reports 3, no. 1 (2010): 141-147. https://doi.org/10.3892/mmr_00000231