LAUSR

Long non-coding RNAs (lncRNAs), longer than 200 nucleotides in length, function in a wide range of processes by diverse mechanisms. lncRNAs are attracting research interest in the field of cancer research though their roles in regulation of oncogenes and/or tumor suppressors remain rather elusive. In order to search for MYC-modulating lncRNA, we performed a global search for lncRNAs affecting MYC activity using a systems biology-based approach with a K supercomputer and the GIMLET algorism based on local distance correlations. Consequently, MYMLR was identified and experimentally shown to maintain MYC transcriptional activity despite its low levels of expression and cell cycle progression. A proteomic search for MYMLR-binding proteins identified PCBP2, which transcriptionally regulates MYC expression in cooperation with MYMLR. Mechanistically, MYMLR places a 557-kb upstream enhancer region to make the MYC promoter and enhancer regions reside in the proximity. These findings implicate a crucial role for MYMLR in regulation of the archetypical oncogene MYC, and warrant future studies regarding the involvement of low copy number lncRNAs in regulation of other crucial oncogenes and tumor suppressor genes in cancer development. Citation Format: Taisuke Kajino, Teppei Shimamura, Shuyi Gong, Kiyoshi Yanagisawa, Masahiro Nakatochi, Sebastian Griesing, Yukako Shimada, Keiko Kano, Motoshi Suzuki, Satoru Miyano, Takashi Takahashi. Divergent lncRNA MYMLR regulates MYC by eliciting DNA looping and promoter-enhancer interaction [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 2464.