Excessive miR-25-3p maturation via N6-methyladenosine stimulated by cigarette smoke promotes pancreatic cancer progression

Jialiang Zhang,Xu Che,Liping Tan,Chengfeng Wang,Zexian Liu,Jiachun Su,Jian Zheng,Rufu Chen,Shengping Li,Qi Zhao,Chen Wu,Rui Xu ,Shusen Zheng ,Wen Tan,Guolin Li,Zhiqiang Fu,Ying Ye,Wei‐Hua Jia ,Mu Sheng Zeng ,Yanfen Zheng,Zhixiang Zuo,Mei Li,Huilin Ye,Dan Xie,Ling Pan,Dongmei Mai,Ruihong Bai,Dong Lin

doi:10.1038/s41467-019-09712-x

Abstract

N6-methyladenosine (m6A) modification is an important mechanism in miRNA processing and maturation, but the role of its aberrant regulation in human diseases remained unclear. Here, we demonstrate that oncogenic primary microRNA-25 (miR-25) in pancreatic duct epithelial cells can be excessively maturated by cigarette smoke condensate (CSC) via enhanced m6A modification that is mediated by NF-κB associated protein (NKAP). This modification is catalyzed by overexpressed methyltransferase-like 3 (METTL3) due to hypomethylation of the METTL3 promoter also caused by CSC. Mature miR-25, miR-25-3p, suppresses PH domain leucine-rich repeat protein phosphatase 2 (PHLPP2), resulting in the activation of oncogenic AKT-p70S6K signaling, which provokes malignant phenotypes of pancreatic cancer cells. High levels of miR-25-3p are detected in smokers and in pancreatic cancers tissues that are correlated with poor prognosis of pancreatic cancer patients. These results collectively indicate that cigarette smoke-induced miR-25-3p excessive maturation via m6A modification promotes the development and progression of pancreatic cancer.

Highlights

N6-methyladenosine (m6A) modification is an important mechanism in miRNA processing and maturation, but the role of its aberrant regulation in human diseases remained unclear
Measurement of these 26 miRNAs in surgically removed non-tumor pancreatic tissue samples collected at the two cancer centers showed that only the miR-25-3p level was significantly higher in smokers (N = 67) than in nonsmokers (N = 108; Fig. 1d) and the levels were significantly higher in pancreatic ductal adenocarcinoma (PDAC) than in non-tumor samples in both patient groups (Fig. 1e)
We found that methyltransferase-like 3 (METTL3) or NKAP depletion substantially reduced the interaction of endogenous DiGeorge critical region 8 (DGCR8) with pri-miR-25 (Fig. 4i, j), indicating that it was NKAP that recruits DGCR8 to interact with pri-miR-25

Summary

Introduction

N6-methyladenosine (m6A) modification is an important mechanism in miRNA processing and maturation, but the role of its aberrant regulation in human diseases remained unclear. We demonstrate that oncogenic primary microRNA-25 (miR-25) in pancreatic duct epithelial cells can be excessively maturated by cigarette smoke condensate (CSC) via enhanced m6A modification that is mediated by NF-κB associated protein (NKAP). This modification is catalyzed by overexpressed methyltransferase-like 3 (METTL3) due to hypomethylation of the METTL3 promoter caused by CSC. High levels of miR-25-3p are detected in smokers and in pancreatic cancers tissues that are correlated with poor prognosis of pancreatic cancer patients These results collectively indicate that cigarette smoke-induced miR-25-3p excessive maturation via m6A modification promotes the development and progression of pancreatic cancer. This METTL3-miR-25-3p-PHLPP2-AKT axis promotes the initiation and the progression of PDAC

Methods

Results

Conclusion