Alterations of the LKB1 Gene in Lung Adenocarcinomas Induced by N-Nitrosobis(2-Hydroxypropyl)amine in Rats

Objective: Germ line mutations of the LKB1 gene cause the autosomal dominant Peutz-Jeghers syndrome (PJS), and PJS has also been associated with an increased risk of developing cancers, suggesting LKB1 may act as a tumor suppressor in PJS. By contrast, LKB1 mutations are rare events in most sporadic tumors in non-PJS patients, except for lung cancers. To better understand the involvement of LKB1 gene alterations during lung carcinogenesis, we investigated the LKB1 gene mutations and expressions in lung adenocarcinomas induced by N-nitrosobis(2-hydroxypropyl)amine (BHP) in rats. Methods: Male Wistar rats, 6 weeks old, were given 2,000 ppm BHP in their drinking water for 12 weeks and maintained without further treatment until they were sacrificed at 25 weeks. A total of 15 lung adenocarcinomas were obtained, and genomic DNA was extracted for the search of mutations using polymerase chain reaction (PCR)-single strand conformation polymorphism analysis. To assess altered expressions of the LKB1 gene, reverse transcriptionPCR analysis was also performed. Results: No mutations were found throughout exons 1–9 in any of the tumors. Aberrant transcripts bearing deletions of nucleotides 216–1459, Received: March 1, 2010 Accepted after revision: March 19, 2010 Toshifumi Tsujiuchi Laboratory of Cancer Biology and Bioinformatics Department of Life Science, Faculty of Science and Engineering Kinki University, 3-4-1, Kowakae, Higashiosaka, Osaka 577-8502 (Japan) Tel. +81 6 6772 2332, Fax +81 6 6723 2721, E-Mail ttujiuch @ life.kindai.ac.jp © 2010 S. Karger AG, Basel 1015–2008/10/0774–0225$26.00/0 Accessible online at: www.karger.com/pat D ow nl oa de d by : 54 .7 0. 40 .1 1 11 /1 9/ 20 17 9 :4 0: 22 A M