Expression of nerve growth factor-induced clone B subfamily and pro-opiomelanocortin gene in lung cancer cell lines

Ner ie growth factor-induced clone B (NGFI-B), Nur-related factor 1, and ne uron-derived orphan receptor-1 have structural features of ligand-activated transcriptional regulators and constitute the NGFI-B subfamily within the nuclear receptor superfamily. The NGFI-B subfamily is highly expressed in n euroendocrine organs and regulates the pro-opiomelanocortin (POMC) gene. Sm all-cell lung cancer (SCLC) is considered to be a neuroendocrine tumor that produces large numbers of polypeptide hormones. In this study we measured the NGFI-B subfamily and POMC messenger RNA (mRNA) levels in various lung c ancer cell lines by means of the quantitative reverse transcription-polymer ase chain reaction, and evaluated the correlations between expression of th ese genes and polypeptide hormone productions. We also examined the effect of antisense oligonucleotide to NGFI-B mRNA on the expression of POMC mRNA, The NGFI-B subfamily and POMC mRNAs were highly expressed in SCLC cell lin es. In addition, there were strong correlations between the NGFI-B, POMC ge nes, and the adrenocorticotropin hormone (ACTH) level. Further, the antisen se oligonucleotide significantly suppressed POMC gene expression. We conclu de that the NGFI-B subfamily was a significant molecule in SCLC and that th e NGFI-B was a positive transcriptional factor for ACTH production.