Soochow University Laboratory of Cancer Molecular Genetics, Suzhou Medical College of Soochow University, Suzhou, China.
Department of Genetics, School of Biology and Basic Medical Sciences, Suzhou Medical College of Soochow University, Suzhou, China.
FASEB J. 2022 May;36(5):e22283. doi: 10.1096/fj.202200005RR.
AlkB homolog 5 (ALKBH5) has been revealed as a key RNA N -methyladenosine (m A) demethylase that is implicated in development and diseases. However, the function of ALKBH5 in TGF-β-induced epithelial-mesenchymal transition (EMT) and tumor metastasis of non-small-cell lung cancer (NSCLC) remains unknown. Here, we firstly show that ALKBH5 expression is significantly reduced in metastatic NSCLC. ALKBH5 overexpression inhibits TGF-β-induced EMT and invasion of NSCLC cells, whereas ALKBH5 knockdown promotes the corresponding phenotypes. ALKBH5 overexpression suppresses TGF-β-stimulated NSCLC cell metastasis in vivo. ALKBH5 overexpression decreases the expression and mRNA stability of TGFβR2 and SMAD3 but increases those of SMAD6, while ALKBH5 knockdown causes the opposite results. Importantly, ALKBH5 overexpression or knockdown leads respectively to an attenuated or augmented phosphorylation of SMAD3, an indispensable downstream effector that activates TGF-β/SMAD signaling. Moreover, m A-binding proteins YTHDF1/3 promotes TGFβR2 and SMAD3 expression, and YTHDF2 inhibits SMAD6 expression. YTHDF1/2/3 facilitates TGF-β-stimulated EMT and invasion of NSCLC cells. Mechanistically, ALKBH5 affects TGFβR2, SMAD3 and SMAD6 expression and mRNA stability by erasing m A modification in NSCLC cells. ALKBH5 weakens YTHDF1/3-mediated TGFβR2 and SMAD3 mRNA stabilization, and abolishes YTHDF2-mediated SMAD6 mRNA degradation, supporting the notion that ALKBH5 inhibits TGF-β-induced EMT and invasion of NSCLC cells via YTHD1/2/3-mediated mechanism. Taken together, our findings highlight an important role of ALKBH5 in regulating TGF-β/SMAD signaling, and establish a mechanistic interaction of ALKBH5 with TGFβR2/SMAD3/SMAD6 for controlling TGF-β-induced EMT in NSCLCs.
ALKB 同源物 5（ALKBH5）已被揭示为一种关键的 RNA N6-甲基腺苷（m A）去甲基化酶，其参与发育和疾病。然而，ALKBH5 在转化生长因子-β（TGF-β）诱导的非小细胞肺癌（NSCLC）上皮-间质转化（EMT）和肿瘤转移中的作用尚不清楚。在这里，我们首先表明，转移性 NSCLC 中 ALKBH5 的表达显著降低。ALKBH5 过表达抑制 TGF-β诱导的 NSCLC 细胞 EMT 和侵袭，而 ALKBH5 敲低则促进相应的表型。ALKBH5 过表达抑制 TGF-β刺激的 NSCLC 细胞在体内的转移。ALKBH5 过表达降低 TGFβR2 和 SMAD3 的表达和 mRNA 稳定性，但增加 SMAD6 的表达，而 ALKBH5 敲低则导致相反的结果。重要的是，ALKBH5 过表达或敲低分别导致 SMAD3 的磷酸化减弱或增强，SMAD3 是激活 TGF-β/SMAD 信号的不可或缺的下游效应子。此外，m A 结合蛋白 YTHDF1/3 促进 TGFβR2 和 SMAD3 的表达，而 YTHDF2 抑制 SMAD6 的表达。YTHDF1/2/3 促进 TGF-β 刺激的 NSCLC 细胞 EMT 和侵袭。在机制上，ALKBH5 通过消除 NSCLC 细胞中的 m A 修饰来影响 TGFβR2、SMAD3 和 SMAD6 的表达和 mRNA 稳定性。ALKBH5 减弱了 YTHDF1/3 介导的 TGFβR2 和 SMAD3 mRNA 稳定，消除了 YTHDF2 介导的 SMAD6 mRNA 降解，这表明 ALKBH5 通过 YTHD1/2/3 介导的机制抑制 TGF-β 诱导的 NSCLC 细胞 EMT 和侵袭。总之，我们的研究结果强调了 ALKBH5 在调节 TGF-β/SMAD 信号中的重要作用，并建立了 ALKBH5 与 TGFβR2/SMAD3/SMAD6 的机制相互作用，以控制 TGF-β 诱导的 NSCLCs 中的 EMT。
