Abstract 975: Hypoxic long noncoding RNA NDRG1-OT1 inhibit NDRG1 in MCF-7 breast cancer cell line

Hypoxia is a crucial factor that associated with solid tumor progression by driving multiple signaling pathway. Our lab previously reported that NDRG1 was oxygen-responsive genes and could affect cellular function in a breast cancer cell line MCF-7. Long-non coding RNAs (lncRNAs) have recently emerged as important regulators of tumor progression by participating in several process of gene expression. However, it is unclear whether lncRNAs are responsed to oxygen concentrations in breast cancer. Therefore, the aim of this study is to identify lncRNAs which are responsive upon changes in oxygen concentrations, and its regulatory mechanism in the breast cancer MCF-7 cells. We investigated the differentially expressed lncRNAs in different oxygen concentrations using next-generation sequencing (NGS) and validated these results through quantitative reverse transcription polymerase chain reaction (qRT-PCR). We found an lncRNA, NDRG1-OT1, that was up-regulated during hypoxia and down-regulated during reoxygenation. Next, we identified the differentially expressed genes regulated by NDRG1-OT1 using microarrays and confirmed these results through qRT-PCR and Western blotting. We found an oxygen responsive gene, NDRG1, was inhibited by NDRG1-OT1. Furthermore, Ingenuity Pathway Analysis(IPA) indicated that NDRG1-OT1 could involve in the Ubiquitin-proteasome pathway. We considered NDRG1-OT1 might regulate NDRG1 stability and ubiquitination, and we are proving these possibility by immunoblotting and immunoprecipitation. These findings may provide new insights into epigenetic regulation of breast cancer during hypoxia. Citation Format: Hsin-Chen Lin, Liang-Chuan Lai, Hsing-Guang Chen, Hung-Hsin Chen, Mei-Hung Chang, Mong-Hsun Tsai, Eric Y. Chung. Hypoxic long noncoding RNA NDRG1-OT1 inhibit NDRG1 in MCF-7 breast cancer cell line. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 975.