Inhibition of expression of ornithine decarboxylase by c-myc antisense oligonucleotide at the promotion stage of lung tumorigenesis in mice

Regulation of ornithine decarboxylase (ODC) expression at a promotion stage of lung carcinogenesis is a key clue to suppress the cancer. In this study , we investigated that the ODC induction at the promotion stage of lung car cinogenesis in mice could be inhibited through the suppression of the expre ssion of c-myc, a transcription factor for ODC. The treatment with c-myc an tisense oligonucleotide decreased the carcinogen-elevated level of pulmonar y ODC protein at the promotion stage, but the sense oligonucleotide had no influence on the level. Overall, it is possible that the induction of ODC i n the carcinogenic process of lung is regulated at its transcriptional leve l.