Alterations of the retinoblastoma-related gene RB2/p130 in lung adenocarcinomas induced by N-nitrosobis(2-hydroxypropyl)amine in rats.

Alteration of the retinoblastoma-related gene RB2/p130 was investigated in lung adenocarcinomas induced by N-nitrosobis(2-hydroxypropyl)amine (BHP) in male Wistar rats. At 6 wk of age, 21 animals were given 2000 ppm of BHP in their drinking water for 12 wk and then maintained without further treatment until they were killed at the end of week 25. A total of 21 lung adenocarcinomas were obtained, and total RNAs were extracted from each for mutation analysis of RB2/p130 by the reverse transcription-polymerase chain reaction-single-strand comformation polymorphism approach. No mutations were found in exons 19-22. However, examination of the expression of the RB2/p130 gene by Northern blot analysis showed mRNA levels to be significantly lower than those of normal lung tissues. Western blot analysis showed reduction of the pRb2/p130 protein in all of the adenocarcinomas examined. These results suggest that alteration of the RB2/p130 gene may play important roles in the development of lung adenocarcinomas induced by BHP in rats.