Adenylate Kinase 4 Modulates the Resistance of Breast Cancer Cells to Tamoxifen through an m6A-Based Epitranscriptomic Mechanism
Adenylate Kinase 4 Modulates the Resistance of Breast Cancer Cells to Tamoxifen through an m6A-Based Epitranscriptomic Mechanism
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DOI：
10.1016/j.ymthe.2020.09.007
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发表时间：
2020-12-02
影响因子：
12.4
通讯作者：
Wang, Yinsheng
中科院分区：
文献类型：
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作者：
Liu, Xiaochuan;Gonzalez, Gwendolyn;Wang, Yinsheng
N-6-甲基腺苷（N-6-methyladenosine，m（6）A）是mRNA中最丰富的内部修饰，这种甲基化是mRNA稳定性和翻译效率的重要调节机制。在这项研究中，我们发现腺苷酸激酶4（AK 4）和m（6）A书写肌L3的蛋白水平在他莫昔芬耐药（TamR）MCF-7细胞中显著高于亲本细胞。TamR MCF-7细胞还表现出AK 4 mRNA的5 '非翻译区（5 ' UTR）中多个m（6）A共有基序位点的甲基化增加，并且TamR MCF-7细胞中胃L3的遗传缺失导致AK 4蛋白水平降低和对他莫昔芬的抗性减弱。此外，我们观察到TamR MCF-7细胞中活性氧（ROS）和p38活性水平增加，并且在AK 4基因耗尽后两者都减少。反过来，在MCF-7细胞中AK 4的过表达刺激ROS和p38磷酸化水平，并抑制线粒体凋亡。此外，清除细胞内ROS导致p38活性降低，并使TamR MCF-7细胞对他莫昔芬重新敏感。因此，我们的研究结果揭示了一种新的m（6）A介导的表位转录调控机制的AK 4，阐明了细胞途径，通过增加AK 4的表达有助于他莫昔芬耐药性，并揭示AK 4作为一个潜在的治疗目标，克服他莫昔芬耐药性。
N-6-methyladenosine (m(6)A) is the most abundant internal modification in mRNA and this methylation constitutes an important regulatory mechanism for the stability and translational efficiency of mRNA. In this study, we found that the protein levels of adenylate kinase 4 (AK4) and m(6)A writer METTL3 are significantly higher in tamoxifenresistant (TamR) MCF-7 cells than in parental cells. The TamR MCF-7 cells also exhibit increased methylation at multiple m(6)A consensus motif sites in the 5 ' untranslated region (5 ' UTR) of AK4 mRNA, and genetic depletion of METTL3 in TamR MCF-7 cells led to a diminished AK4 protein level and attenuated resistance to tamoxifen. In addition, we observed augmented levels of reactive oxygen species (ROS) and p38 activity in TamR MCF-7 cells, and both are diminished upon genetic depletion of AK4. Reciprocally, overexpression of AK4 in MCF-7 cells stimulates ROS and p38 phosphorylation levels, and it suppresses mitochondrial apoptosis. Moreover, scavenging of intracellular ROS leads to reduced p38 activity and re-sensitizes TamR MCF-7 cells to tamoxifen. Thus, our results uncover a novel m(6)A-mediated epitranscriptomic mechanism for the regulation of AK4, illustrate the cellular pathways through which increased AK4 expression contributes to tamoxifen resistance, and reveal AK4 as a potential therapeutic target for overcoming tamoxifen resistance.