Transcriptional regulation of the human osteopontin promoter in non-small cell lung cancer

Background: Elevated osteopontin (OPN) transcription often correlates with increased metastatic potential of transformed cells, and OPN has been shown to enhance metastatic ability. We hypothesized that transcription determines OPN expression, tried to find out response element resion in the DNA sequence element and suppression molecules. Methods: We investigated the transcriptional regulation of OPN in non-small celll lung cancer cell lines. These elements were treated with pp2 (src tyrosine kinase inhibitor), FTI (Farnesyl transferase inhibitor), and 2BP (2 bromo palmitate) in order that confirm suppress transcriptional expression. Results: Deletion and mutagenesis analyses of the OPN promoter region identified a proximal promoter element (-123 to -89 relative to the transcription initiation site) that is essential for maintaining high level of OPN expression in the tumor cells. Proximal promoter elements (-123 and -89) were treated with pp2, FTI and 2BP, whether if transcriptional expression could be suppressed by these molecules. In case of FTI, OPN expression was suppressed, but statistical significance wasn't meaningful. Conclusion: The proximal promoter element (-123 to -89) was essential for maintaining high level of OPN expression in non-small cell lung cancer cell lines. Further investigation for searching material to suppress OPN expression is needed.