Abstract LB-153: In vivo visualization of the targeted DNA methylation

Abstract

Abstract DNA methylation is a dominant silencing epigenetic modification that is inheritable in somatic cells. The recruitment of DNA methylation was proven to be able to reshape the cell physiology and cause tumorigenesis. The reversible nature of the methylation modification also makes the DNA methylation a therapeutic target and the monitoring of the methylation/demethylation dynamics in vivo is thus important for the development of demethylation agents. A targeted DNA methylation method and a two-component reporter system were combined to monitor the increase and demolishment of DNA methylation in vivo. The two constructs of the reporter systems are: target gene promoter (like HIC1 and ENSA) linked with the Tet repressor gene; the other is the Tet operator linked with the reporter like EGFP (in cell), IFP and iRFP. Both constructs were co-transfected into cells like mesenchymal stem cells, MDA-MB-231 and HCT116, and stable clones with both constructs were isolated and validated. Targeted DNA methylation method was used to transfect the isolated cell and, as the increase of DNA methylation, the reporters expressed. The increased methylation was then quenched after the adding of demethylation agents. To test this system in vivo, cells with both constructs were injected into the immune-deficient mice and the tumors grew afterward. Targeted DNA methylation was performed in vivo and the increase of methylation/expression of reporter genes were observed by fluorescence-based tomography. This combined system is also effective to monitor the demethylation effects of the demethylation agents. (Supported by: NSC- 102-2320-B-194-003-MY3 and NSC-102-2314-B-371- 003-MY3, MOST Taiwan) Citation Format: Yao-Li Chen, Shou-Tung Chen, Chun-Chun Chung, Chia-Chen Hsu, Ping-Yi Lin, Wan-Ling Chuang, Yi-Ju Chu, Yu-Wei Leu, Shu-Huei Hsiao. In vivo visualization of the targeted DNA methylation. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-153. doi:10.1158/1538-7445.AM2015-LB-153