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Abstract 5427: Inhibition of hypoxia-inducible factor 1 (HIF-1) transcriptional activity and cell mobility via G9a/GLP-mediated methylation of HIF-1α

Hypoxia-inducible factor 1 (HIF-1) is a main regulator of cellular response to hypoxia and its transcriptional activity is crucial for cancer cell migration and invasion. Post-translational modifications of the α subunit of HIF-1 (HIF-1α) play dominant roles in regulating its function. In this study, we demonstrated that the lysine methyltransferases G9a and GLP catalyzed mono- and di-methylation of HIF-1α at lysine (K) 674 in vitro and in vivo. Functionally, K674 methylation suppressed HIF-1 transcriptional activity as well as expression of the HIF-1 target genes including PTGS1, NDNF, SLC6A3, and Linc01132 in human glioblastoma U251MG cells. Moreover, mutation of K674 of HIF-1α significantly enhanced U251MG cell migration under hypoxia. Importantly, we found that G9a level was downregulated by hypoxia in glioblastoma, which was negatively correlated with PTGS1 expression and survival rate in glioblastoma patients. These findings reveal a novel naturally existing negative feedback mechanism that maintains high activity of HIF-1 and cell mobility in human glioblastoma. Citation Format: Lei Bao, Yan Chen, Hsien-Tsung Lai, Cheng-Ming Chiang, Gregg L. Semenza, Yingfei Wang, Weibo Luo. Inhibition of hypoxia-inducible factor 1 (HIF-1) transcriptional activity and cell mobility via G9a/GLP-mediated methylation of HIF-1α [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5427.