Shimizu Kyoko, Shimoichi Yozo, Hinotsume Daisei, Itsuzaki Yumi, Fujii Hiromasa, Honoki Kanya, Tsujiuchi Toshifumi
Laboratory of Cancer Biology and Bioinformatics, Department of Life Science, Faculty of Science and Engineering, Kinki University, Higashiosaka, Osaka, Japan.
Mol Carcinog. 2006 Sep;45(9):710-4. doi: 10.1002/mc.20207.
Gap junctions are mediated by intercellular channels that connect adjacent cells and are composed of Connexin (Cx) proteins. A member of the Cx family, Cx26 is considered a potential tumor suppressor in several cancers. The expression of Cx26 gene and its methylation status in rat lung adenocarcinomas induced by N-nitrosobis(2-hydroxypropyl)amine (BHP) were investigated. Six-wk-old male Wistar rats were given 2,000 ppm BHP in their drinking water for 12 wk and maintained without further treatment until they were sacrificed at 25 wk. A total of nine lung adenocarcinomas were obtained and total RNA was extracted to assess expression by real-time quantitative reverse transcription (RT)-polymerase chain reaction (PCR). Five out of nine adenocarcinomas showed reduced expression compared with normal lung tissue. We next performed a bisulfite sequence analysis to measure the methylation status of the 5' upstream region of the Cx26 gene in two normal lung tissues and five lung adenocarcinomas that showed reduced expression of Cx26. All five adenocarcinomas were highly methylated in the 5' upstream region, while the two normal lung tissues were unmethylated. This suggests that aberrant methylation of the Cx26 gene may be involved in the development of lung adenocarcinomas induced by BHP in rats.
间隙连接由连接相邻细胞的细胞间通道介导，这些通道由连接蛋白（Cx）组成。Cx家族的成员Cx26在几种癌症中被认为是一种潜在的肿瘤抑制因子。研究了N-亚硝基双（2-羟丙基）胺（BHP）诱导的大鼠肺腺癌中Cx26基因的表达及其甲基化状态。六周龄雄性Wistar大鼠在饮用水中给予2000 ppm BHP，持续12周，然后不再接受进一步治疗，直至25周时处死。共获得九个肺腺癌组织，提取总RNA，通过实时定量逆转录（RT）-聚合酶链反应（PCR）评估表达情况。九个腺癌中有五个与正常肺组织相比表达降低。接下来，我们进行了亚硫酸氢盐序列分析，以测量两个正常肺组织和五个Cx26表达降低的肺腺癌中Cx26基因5'上游区域的甲基化状态。所有五个腺癌在5'上游区域高度甲基化，而两个正常肺组织未甲基化。这表明Cx26基因的异常甲基化可能参与了BHP诱导的大鼠肺腺癌的发生发展。
