Alternative polyadenylation reprogramming of MORC2 induced by NUDT21 loss promotes KIRC carcinogenesis
Yuqin Tan, Tong Zheng, Zijun Su, Min Chen, Suxiang Chen, Rui Zhang, Ruojiao Wang, Ke Li, Ning Na
Yuqin Tan, Tong Zheng, Zijun Su, Min Chen, Suxiang Chen, Rui Zhang, Ruojiao Wang, Ke Li, Ning Na
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Research Article Oncology

Alternative polyadenylation reprogramming of MORC2 induced by NUDT21 loss promotes KIRC carcinogenesis

Abstract

Alternative polyadenylation (APA), a posttranscriptional mechanism of gene expression via determination of 3′UTR length, has an emerging role in carcinogenesis. Although abundant APA reprogramming is found in kidney renal clear cell carcinoma (KIRC), which is one of the major malignancies, whether APA functions in KIRC remains unknown. Herein, we found that chromatin modifier MORC2 gained oncogenic potential in KIRC among the genes with APA reprogramming, and moreover, its oncogenic potential was enhanced by 3′UTR shortening through stabilization of MORC2 mRNA. MORC2 was found to function in KIRC by downregulating tumor suppressor DAPK1 via DNA methylation. Mechanistically, MORC2 recruited DNMT3A to facilitate hypermethylation of the DAPK1 promoter, which was strengthened by 3′UTR shortening of MORC2. Furthermore, loss of APA regulator NUDT21, which was induced by DNMT3B-mediated promoter methylation, was identified as responsible for 3′UTR shortening of MORC2 in KIRC. Additionally, NUDT21 was confirmed to act as a tumor suppressor mainly depending on downregulation of MORC2. Finally, we designed an antisense oligonucleotide (ASO) to enhance NUDT21 expression and validated its antitumor effect in vivo and in vitro. This study uncovers the DNMT3B/NUDT21/APA/MORC2/DAPK1 regulatory axis in KIRC, disclosing the role of APA in KIRC and the crosstalk between DNA methylation and APA.

Authors

Yuqin Tan, Tong Zheng, Zijun Su, Min Chen, Suxiang Chen, Rui Zhang, Ruojiao Wang, Ke Li, Ning Na

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Figure 9

NUDT21 functions as a tumor suppressor mainly depending on MORC2 downregulation.

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NUDT21 functions as a tumor suppressor mainly depending on MORC2 downreg...
(A) Immunoblotting was performed to evaluate the expression of Flag-NUDT21 and Flag-MORC2 in Caki-1 and A498 cells transfected with empty Flag vector or Flag-NUDT21 plasmid with or without MORC2 recovery. (B) CCK8 assays were performed to evaluate the proliferation rate of Caki-1 and A498 cells transfected with empty Flag vector or Flag-NUDT21 with or without MORC2 recovery (n = 3). (C) Colony formation assays were performed and quantitatively analyzed to evaluate the clonogenicity of Caki-1 and A498 cells transfected with empty Flag vector or Flag-NUDT21 with or without MORC2 recovery (n = 3). (D and E) In vivo xenograft tumor formation experiment was performed (D) and quantitatively analyzed (E) with control Caki-1 and NUDT21-stably expressed Caki-1 cells with or without MORC2 recovery (n = 5 per group). (F) Immunoblotting was performed to evaluate expression of NUDT21 and MORC2 in Caki-1 and A498 cells transfected with control siRNA or NUDT21-specific siRNA with or without MORC2 silencing. (G) CCK8 assays were performed to evaluate the proliferation rate of Caki-1 and A498 cells transfected with control siRNA or NUDT21-specific siRNA with or without MORC2 silencing (n = 3). (H) Colony formation assays were performed and quantitatively analyzed to evaluate the clonogenicity of Caki-1 and A498 cells transfected with control siRNA or NUDT21-specific siRNA with or without MORC2 silencing (n = 3). (I) Prognosis of patients with KIRC with high NUDT21 expression and low MORC2 expression or low NUDT21 expression and high MORC2 expression was analyzed with Xiantao database (www.xiantaozi.com) depending on TCGA data. All data represent the mean ± SD. Two-tailed t test analyses were performed. *P < 0.05; **P < 0.01; ***P < 0.001.