R-2HG downregulates ERα to inhibit cholangiocarcinoma via the FTO/m6A-methylated ERα/miR16-5p/YAP1 signal pathway

Yuan Gao; Xiwu Ouyang; Li Zuo; Yao Xiao; Yin Sun; Chawnshang Chang; Xihu Qin; Shuyuan Yeh

doi:10.1016/j.omto.2021.06.017

R-2HG downregulates ERα to inhibit cholangiocarcinoma via the FTO/m6A-methylated ERα/miR16-5p/YAP1 signal pathway

Mol Ther Oncolytics. 2021 Jul 10:23:65-81. doi: 10.1016/j.omto.2021.06.017. eCollection 2021 Dec 17.

Authors

Yuan Gao^{1

2}, Xiwu Ouyang^{2

3}, Li Zuo¹, Yao Xiao^{2

3}, Yin Sun², Chawnshang Chang², Xihu Qin¹, Shuyuan Yeh²

Affiliations

¹ Department of Hepato-Biliary-Pancreatic Surgery, The Affiliated Changzhou No. 2 People's Hospital of Nanjing Medical University, Changzhou, Jiangsu 213003, China.
² George Whipple Lab for Cancer Research, Departments of Urology, Pathology, and Radiation Oncology, and The Wilmot Cancer Institute, University of Rochester Medical Center, Rochester, NY 14642, USA.
³ Department of General Surgery, Xiangya Hospital, Central South University, Changsha 410008, China.

Abstract

Isocitrate dehydrogenase (IDH) mutations increase (R)-2-hydroxyglutarate (R-2HG) production; however, functional mechanisms of R-2HG in regulating cholangiocarcinoma (CCA) development remain to be further investigated. We first applied the CRISPR-Cas9 gene-editing system to create IDH1R132H-mutated CCA cells. Interestingly, our data showed that R-2HG could function through downregulating estrogen receptor alpha (ERα) and Yes-associated protein 1 (YAP1) pathways to decrease CCA growth. Detailed mechanistic studies revealed that R-2HG could target and degrade the fat mass and obesity-associated protein (FTO), the first identified mRNA demethylase. This reduced FTO can increase the N ⁶-methyladenosine (m6A) to methylate the mRNA of ERα, and consequently decrease protein translation of the ERα. Further mechanistic studies revealed that ERα could transcriptionally suppress miR-16-5p expression, which could then increase YAP1 expression due to the reduced miR-16-5p binding to the 3' UTR of YAP1. Furthermore, data from the pre-clinical animal model with implantation of IDH1R132H QBC939 cells demonstrated that R-2HG generated by the IDH1 mutation could downregulate ERα and YAP1 to suppress CCA tumor growth. Taken together, our new findings suggested that IDH1 mutation-induced R-2HG could suppress CCA growth via regulating the FTO/m6A-methylated ERα/miR16-5p/YAP1 signaling pathway. Upregulating R-2HG or downregulating the ERα signal by short hairpin RNA ERα (shERα) or antiestrogen could be effective strategies to inhibit CCA.

Keywords: (R)-2-hydroxyglutarate; ERα; YAP1; cholangiocarcinoma; miR16-5p.