Targeting Retinoic Acid Treatment of Lung Cancers

A novel yeast screen sensitive to retinoid-X receptor (RXR) transcriptional activation resulted in the isolation of the rat homologue of the mouse NPDC-I gene. NPDC-I has been shown to be involved in the control of neural cell proliferation and differentiation, possibly through interactions with the cell cycle promoting transcription factor E2F-I. Although the amino acid sequence of NPDC-I is highly conserved between mouse, rat and human homologues, their tissue specific expression varies. A potential for a direct protein:protein interaction between NPDC-I and RXR was observed in vitro and NPDC-I facilitated RXR dimer DNA binding in vitro. Expression of NPDC-I also enhances the alltrans retinoic acid response in mammalian cell transcription assays. The present results suggest that NPDC-I functions to enhance transcription regulating factors~ DNA binding function and influences retinoid signaling by direct interaction with RXR.