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Shen H, An O, Ren X, Song Y, Tang SJ, Ke XY, Han J, Tay DJT, Ng VHE, Molias FB, Pitcheshwar P, Leong KW, Tan KK, Yang H, Chen L. ADARs act as potent regulators of circular transcriptome in cancer. Nat Commun 2022; 13:1508. [PMID: 35314703 PMCID: PMC8938519 DOI: 10.1038/s41467-022-29138-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 02/15/2022] [Indexed: 01/01/2023] Open
Abstract
Circular RNAs (circRNAs) are produced by head-to-tail back-splicing which is mainly facilitated by base-pairing of reverse complementary matches (RCMs) in circRNA flanking introns. Adenosine deaminases acting on RNA (ADARs) are known to bind double-stranded RNAs for adenosine to inosine (A-to-I) RNA editing. Here we characterize ADARs as potent regulators of circular transcriptome by identifying over a thousand of circRNAs regulated by ADARs in a bidirectional manner through and beyond their editing function. We find that editing can stabilize or destabilize secondary structures formed between RCMs via correcting A:C mismatches to I(G)-C pairs or creating I(G).U wobble pairs, respectively. We provide experimental evidence that editing also favors the binding of RNA-binding proteins such as PTBP1 to regulate back-splicing. These ADARs-regulated circRNAs which are ubiquitously expressed in multiple types of cancers, demonstrate high functional relevance to cancer. Our findings support a hitherto unappreciated bidirectional regulation of circular transcriptome by ADARs and highlight the complexity of cross-talk in RNA processing and its contributions to tumorigenesis. RNA editing and circRNAs are involved in tumorigenesis. Here the authors report that ADARs regulate the circular transcriptome in a bidirectional manner through and beyond their editing function in multiple cancer cells.
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Bellido Molias F, Sim A, Leong KW, An O, Song Y, Ng VHE, Lim MWJ, Ying C, Teo JXJ, Göke J, Chen L. Antisense RNAs Influence Promoter Usage of Their Counterpart Sense Genes in Cancer. Cancer Res 2021; 81:5849-5861. [PMID: 34649947 PMCID: PMC9397637 DOI: 10.1158/0008-5472.can-21-1859] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 08/19/2021] [Accepted: 10/11/2021] [Indexed: 01/07/2023]
Abstract
Multiple noncoding natural antisense transcripts (ncNAT) are known to modulate key biological events such as cell growth or differentiation. However, the actual impact of ncNATs on cancer progression remains largely unknown. In this study, we identified a complete list of differentially expressed ncNATs in hepatocellular carcinoma. Among them, a previously undescribed ncNAT HNF4A-AS1L suppressed cancer cell growth by regulating its sense gene HNF4A, a well-known cancer driver, through a promoter-specific mechanism. HNF4A-AS1L selectively activated the HNF4A P1 promoter via HNF1A, which upregulated expression of tumor suppressor P1-driven isoforms, while having no effect on the oncogenic P2 promoter. RNA-seq data from 23 tissue and cancer types identified approximately 100 ncNATs whose expression correlated specifically with the activity of one promoter of their associated sense gene. Silencing of two of these ncNATs ENSG00000259357 and ENSG00000255031 (antisense to CERS2 and CHKA, respectively) altered the promoter usage of CERS2 and CHKA. Altogether, these results demonstrate that promoter-specific regulation is a mechanism used by ncNATs for context-specific control of alternative isoform expression of their counterpart sense genes. SIGNIFICANCE: This study characterizes a previously unexplored role of ncNATs in regulation of isoform expression of associated sense genes, highlighting a mechanism of alternative promoter usage in cancer.
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Affiliation(s)
| | - Andre Sim
- Computational and Systems Biology, Genome Institute of Singapore, Singapore
| | - Ka Wai Leong
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Omer An
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Yangyang Song
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Vanessa Hui En Ng
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Max Wei Jie Lim
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Chen Ying
- Computational and Systems Biology, Genome Institute of Singapore, Singapore
| | - Jasmin Xin Jia Teo
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Jonathan Göke
- Computational and Systems Biology, Genome Institute of Singapore, Singapore.,Corresponding Authors: Leilei Chen, National University of Singapore, Center for Translational Medicine (MD6), 14 Medical Drive, #12-01, S117599 Singapore. Phone: 65-6516-8435; Fax: 65-6516-1873; E-mail: ; and Jonathan Göke,
| | - Leilei Chen
- Cancer Science Institute of Singapore, National University of Singapore, Singapore.,Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,NUS Centre for Cancer Research, Yong Loo Lin School of Medicine, National University Singapore, Singapore.,Corresponding Authors: Leilei Chen, National University of Singapore, Center for Translational Medicine (MD6), 14 Medical Drive, #12-01, S117599 Singapore. Phone: 65-6516-8435; Fax: 65-6516-1873; E-mail: ; and Jonathan Göke,
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Song Y, An O, Ren X, Chan THM, Tay DJT, Tang SJ, Han J, Hong H, Ng VHE, Ke X, Shen H, Pitcheshwar P, Lin JS, Leong KW, Molias FB, Yang H, Kappei D, Chen L. RNA editing mediates the functional switch of COPA in a novel mechanism of hepatocarcinogenesis. J Hepatol 2021; 74:135-147. [PMID: 32693003 DOI: 10.1016/j.jhep.2020.07.021] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 07/08/2020] [Accepted: 07/10/2020] [Indexed: 12/04/2022]
Abstract
BACKGROUND & AIMS RNA editing introduces nucleotide changes in RNA sequences. Recent studies have reported that aberrant adenosine-to-inosine RNA editing is implicated in cancers. Until now, very few functionally important protein-recoding editing targets have been discovered. Here, we investigated the role of a recently discovered protein-recoding editing target COPA (coatomer subunit α) in hepatocellular carcinoma (HCC). METHODS Clinical implication of COPA editing was studied in a cohort of 125 HCC patients. CRISPR/Cas9-mediated knockout of the editing site complementary sequence (ECS) was used to delete edited COPA transcripts endogenously. COPA editing-mediated change in its transcript or protein stability was investigated upon actinomycin D or cycloheximide treatment, respectively. Functional difference in tumourigenesis between wild-type and edited COPA (COPAWTvs. COPAI164V) and the exact mechanisms were also studied in cell models and mice. RESULTS ADAR2 binds to double-stranded RNA formed between edited exon 6 and the ECS at intron 6 of COPA pre-mRNA, causing an isoleucine-to-valine substitution at residue 164. Reduced editing of COPA is implicated in the pathogenesis of HCC, and more importantly, it may be involved in many cancer types. Upon editing, COPAWT switches from a tumour-promoting gene to a tumour suppressor that has a dominant-negative effect. Moreover, COPAI164V may undergo protein conformational change and therefore become less stable than COPAWT. Mechanistically, COPAI164V may deactivate the PI3K/AKT/mTOR pathway through downregulation of caveolin-1 (CAV1). CONCLUSIONS We uncover an RNA editing-associated mechanism of hepatocarcinogenesis by which downregulation of ADAR2 caused the loss of tumour suppressive COPAI164V and concurrent accumulation of tumour-promoting COPAWT in tumours; a rapid degradation of COPAI164V protein and hyper-activation of the PI3K/AKT/mTOR pathway further promote tumourigenesis. LAY SUMMARY RNA editing is a process in which RNA is changed after it is made from DNA, resulting in an altered gene product. In this study, we found that RNA editing of a gene known as coatomer subunit α (COPA) is lower in tumour samples and discovered that this editing process changes COPA protein from a tumour-promoting form to a tumour-suppressive form. Loss of the edited COPA promotes the development of liver cancer.
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Affiliation(s)
- Yangyang Song
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Omer An
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Xi Ren
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117596, Singapore
| | - Tim Hon Man Chan
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore; Department of Laboratory Medicine, Molecular Diagnosis Centre, National University Health System, Singapore 119074, Singapore
| | - Daryl Jin Tai Tay
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Sze Jing Tang
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Jian Han
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - HuiQi Hong
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore; Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117549, Singapore
| | - Vanessa Hui En Ng
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Xinyu Ke
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore; Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117594, Singapore
| | - Haoqing Shen
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Priyankaa Pitcheshwar
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Jaymie Siqi Lin
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Ka Wai Leong
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Fernando Bellido Molias
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Henry Yang
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Dennis Kappei
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117596, Singapore
| | - Leilei Chen
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore; Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117594, Singapore.
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Han J, An O, Hong H, Chan THM, Song Y, Shen H, Tang SJ, Lin JS, Ng VHE, Tay DJT, Molias FB, Pitcheshwar P, Tan HQ, Yang H, Chen L. Suppression of adenosine-to-inosine (A-to-I) RNA editome by death associated protein 3 (DAP3) promotes cancer progression. Sci Adv 2020; 6:eaba5136. [PMID: 32596459 PMCID: PMC7299630 DOI: 10.1126/sciadv.aba5136] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 05/06/2020] [Indexed: 05/02/2023]
Abstract
RNA editing introduces nucleotide changes in RNA sequences. Recent studies have reported that aberrant A-to-I RNA editing profiles are implicated in cancers. Albeit changes in expression and activity of ADAR genes are thought to have been responsible for the dysregulated RNA editome in diseases, they are not always correlated, indicating the involvement of secondary regulators. Here, we uncover DAP3 as a potent repressor of editing and a strong oncogene in cancer. DAP3 mainly interacts with the deaminase domain of ADAR2 and represses editing via disrupting association of ADAR2 with its target transcripts. PDZD7, an exemplary DAP3-repressed editing target, undergoes a protein recoding editing at stop codon [Stop →Trp (W)]. Because of editing suppression by DAP3, the unedited PDZD7WT, which is more tumorigenic than edited PDZD7Stop518W, is accumulated in tumors. In sum, cancer cells may acquire malignant properties for their survival advantage through suppressing RNA editome by DAP3.
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Affiliation(s)
- Jian Han
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Omer An
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - HuiQi Hong
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117549, Singapore
| | - Tim Hon Man Chan
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Yangyang Song
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Haoqing Shen
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Sze Jing Tang
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Jaymie Siqi Lin
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Vanessa Hui En Ng
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Daryl Jin Tai Tay
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Fernando Bellido Molias
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Priyankaa Pitcheshwar
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Hui Qing Tan
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117549, Singapore
| | - Henry Yang
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Leilei Chen
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117594, Singapore
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Tang SJ, Shen H, An O, Hong H, Li J, Song Y, Han J, Tay DJT, Ng VHE, Bellido Molias F, Leong KW, Pitcheshwar P, Yang H, Chen L. Cis- and trans-regulations of pre-mRNA splicing by RNA editing enzymes influence cancer development. Nat Commun 2020; 11:799. [PMID: 32034135 PMCID: PMC7005744 DOI: 10.1038/s41467-020-14621-5] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 01/16/2020] [Indexed: 12/18/2022] Open
Abstract
RNA editing and splicing are the two major processes that dynamically regulate human transcriptome diversity. Despite growing evidence of crosstalk between RNA editing enzymes (mainly ADAR1) and splicing machineries, detailed mechanistic explanations and their biological importance in diseases, such as cancer are still lacking. Herein, we identify approximately a hundred high-confidence splicing events altered by ADAR1 and/or ADAR2, and ADAR1 or ADAR2 protein can regulate cassette exons in both directions. We unravel a binding tendency of ADARs to dsRNAs that involves GA-rich sequences for editing and splicing regulation. ADAR1 edits an intronic splicing silencer, leading to recruitment of SRSF7 and repression of exon inclusion. We also present a mechanism through which ADAR2 binds to dsRNA formed between GA-rich sequences and polypyrimidine (Py)-tract and precludes access of U2AF65 to 3' splice site. Furthermore, we find these ADARs-regulated splicing changes per se influence tumorigenesis, not merely byproducts of ADARs editing and binding.
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Affiliation(s)
- Sze Jing Tang
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599, Singapore
| | - Haoqing Shen
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599, Singapore
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117594, Singapore
| | - Omer An
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599, Singapore
| | - HuiQi Hong
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599, Singapore
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117549, Singapore
| | - Jia Li
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599, Singapore
| | - Yangyang Song
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599, Singapore
| | - Jian Han
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599, Singapore
| | - Daryl Jin Tai Tay
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599, Singapore
| | - Vanessa Hui En Ng
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599, Singapore
| | - Fernando Bellido Molias
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599, Singapore
| | - Ka Wai Leong
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599, Singapore
| | - Priyankaa Pitcheshwar
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599, Singapore
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117594, Singapore
| | - Henry Yang
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599, Singapore
| | - Leilei Chen
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599, Singapore.
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117594, Singapore.
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Hong H, An O, Chan THM, Ng VHE, Kwok HS, Lin JS, Qi L, Han J, Tay DJT, Tang SJ, Yang H, Song Y, Bellido Molias F, Tenen DG, Chen L. Bidirectional regulation of adenosine-to-inosine (A-to-I) RNA editing by DEAH box helicase 9 (DHX9) in cancer. Nucleic Acids Res 2019; 46:7953-7969. [PMID: 29796672 PMCID: PMC6125626 DOI: 10.1093/nar/gky396] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 04/30/2018] [Indexed: 12/25/2022] Open
Abstract
Adenosine-to-inosine (A-to-I) RNA editing entails the enzymatic deamination of adenosines to inosines by adenosine deaminases acting on RNA (ADARs). Dysregulated A-to-I editing has been implicated in various diseases, including cancers. However, the precise factors governing the A-to-I editing and their physiopathological implications remain as a long-standing question. Herein, we unravel that DEAH box helicase 9 (DHX9), at least partially dependent of its helicase activity, functions as a bidirectional regulator of A-to-I editing in cancer cells. Intriguingly, the ADAR substrate specificity determines the opposing effects of DHX9 on editing as DHX9 silencing preferentially represses editing of ADAR1-specific substrates, whereas augments ADAR2-specific substrate editing. Analysis of 11 cancer types from The Cancer Genome Atlas (TCGA) reveals a striking overexpression of DHX9 in tumors. Further, tumorigenicity studies demonstrate a helicase-dependent oncogenic role of DHX9 in cancer development. In sum, DHX9 constitutes a bidirectional regulatory mode in A-to-I editing, which is in part responsible for the dysregulated editome profile in cancer.
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Affiliation(s)
- HuiQi Hong
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Omer An
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Tim H M Chan
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Vanessa H E Ng
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Hui Si Kwok
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Jaymie S Lin
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Lihua Qi
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore.,Duke-NUS Medical School, National University of Singapore, Singapore 169857, Singapore
| | - Jian Han
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Daryl J T Tay
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Sze Jing Tang
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Henry Yang
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Yangyang Song
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Fernando Bellido Molias
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
| | - Daniel G Tenen
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore.,Harvard Stem Cell Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Leilei Chen
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore.,Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117594, Singapore
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