TY - JOUR
T1 - Interplay of m6A and histone modifications contributes to temozolomide resistance in glioblastoma
AU - Li, Fuxi
AU - Chen, Siyun
AU - Yu, Jiaming
AU - Gao, Zhuoxing
AU - Sun, Zhangyi
AU - Yi, Yang
AU - Long, Teng
AU - Zhang, Chuanxia
AU - Li, Yuzhe
AU - Pan, Yimin
AU - Qin, Chaoying
AU - Long, Wenyong
AU - Liu, Qing
AU - Zhao, Wei
N1 - Funding Information:
We thank Dr. Qi Cao for valuable suggestions. This work was supported by the National Key Research and Development Program of China (grant number 2017YFA0103800), the National Natural Science Foundation of China (grant numbers 81972651, 81802974, 81702784, and 31771630), Guangdong Innovative and Entrepreneurial Research Team Program (grant number 2016ZT06S029), and Natural Science Foundation of Guangdong Province (grant number 2017A030312009).
Publisher Copyright:
© 2021 The Authors. Clinical and Translational Medicine published by John Wiley & Sons Australia, Ltd on behalf of Shanghai Institute of Clinical Bioinformatics
PY - 2021/9
Y1 - 2021/9
N2 - Background: Despite the development of new treatment protocols for glioblastoma (GBM), temozolomide (TMZ) resistance remains a primary hindrance. Previous studies, including our study, have shown that aberrant N6-methyladenosine (m6A) modification is implicated in GBM pathobiology. However, the roles and precise mechanisms of m6A modification in the regulation of TMZ resistance in GBM remain unclear. Methods: m6A individual-nucleotide-resolution cross-linking and immunoprecipitation sequencing (miCLIP-seq) was performed to identify m6A modification of transcripts in TMZ-resistant and -sensitive tumors. To explore the role of METTL3 in TMZ resistance, TMZ-resistant GBM cells were transfected with METTL3 shRNA or overexpression lentivirus and then assessed by cell viability, tumor sphere formation, and apoptosis assays. An intracranial GBM xenograft model was developed to verify the effect of METTL3 depletion during TMZ treatment in vivo. ATAC-seq, ChIP-qPCR, and dual-luciferase reporter assays were carried out to verify the role of SOX4/EZH2 in the modulation of METTL3 expression upon TMZ treatment. Results: We demonstrated that TMZ treatment upregulated the expression of the m6A methyltransferase METTL3, thereby increasing m6A modification of histone modification-related gene transcripts. METTL3 is required to maintain the features of GBM stem cells. When combined with TMZ, METTL3 silencing suppressed orthotopic TMZ-resistant xenograft growth in a cooperative manner. Mechanistically, TMZ induced a SOX4-mediated increase in chromatin accessibility at the METTL3 locus by promoting H3K27ac levels and recruiting RNA polymerase II. Moreover, METTL3 depletion affected the deposition of m6A on histone modification-related gene transcripts, such as EZH2, leading to nonsense-mediated mRNA decay. We revealed an important role of EZH2 in the regulation of METTL3 expression, which was via an H3K27me3 modification-independent manner. Conclusions: Our findings uncover the fundamental mechanisms underlying the interplay of m6A RNA modification and histone modification in TMZ resistance and emphasize the therapeutic potential of targeting the SOX4/EZH2/METTL3 axis in the treatment of TMZ-resistant GBM.
AB - Background: Despite the development of new treatment protocols for glioblastoma (GBM), temozolomide (TMZ) resistance remains a primary hindrance. Previous studies, including our study, have shown that aberrant N6-methyladenosine (m6A) modification is implicated in GBM pathobiology. However, the roles and precise mechanisms of m6A modification in the regulation of TMZ resistance in GBM remain unclear. Methods: m6A individual-nucleotide-resolution cross-linking and immunoprecipitation sequencing (miCLIP-seq) was performed to identify m6A modification of transcripts in TMZ-resistant and -sensitive tumors. To explore the role of METTL3 in TMZ resistance, TMZ-resistant GBM cells were transfected with METTL3 shRNA or overexpression lentivirus and then assessed by cell viability, tumor sphere formation, and apoptosis assays. An intracranial GBM xenograft model was developed to verify the effect of METTL3 depletion during TMZ treatment in vivo. ATAC-seq, ChIP-qPCR, and dual-luciferase reporter assays were carried out to verify the role of SOX4/EZH2 in the modulation of METTL3 expression upon TMZ treatment. Results: We demonstrated that TMZ treatment upregulated the expression of the m6A methyltransferase METTL3, thereby increasing m6A modification of histone modification-related gene transcripts. METTL3 is required to maintain the features of GBM stem cells. When combined with TMZ, METTL3 silencing suppressed orthotopic TMZ-resistant xenograft growth in a cooperative manner. Mechanistically, TMZ induced a SOX4-mediated increase in chromatin accessibility at the METTL3 locus by promoting H3K27ac levels and recruiting RNA polymerase II. Moreover, METTL3 depletion affected the deposition of m6A on histone modification-related gene transcripts, such as EZH2, leading to nonsense-mediated mRNA decay. We revealed an important role of EZH2 in the regulation of METTL3 expression, which was via an H3K27me3 modification-independent manner. Conclusions: Our findings uncover the fundamental mechanisms underlying the interplay of m6A RNA modification and histone modification in TMZ resistance and emphasize the therapeutic potential of targeting the SOX4/EZH2/METTL3 axis in the treatment of TMZ-resistant GBM.
KW - glioblastoma
KW - histone modifications
KW - mA
KW - METTL3
KW - TMZ resistance
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U2 - 10.1002/ctm2.553
DO - 10.1002/ctm2.553
M3 - Article
C2 - 34586728
AN - SCOPUS:85115874161
SN - 2001-1326
VL - 11
JO - Clinical and Translational Medicine
JF - Clinical and Translational Medicine
IS - 9
M1 - e553
ER -