ALKBH5 is the main enzyme for m⁶A-based demethylation of RNAs and it has been implicated in many biological and pathophysiological processes. Here, we aimed to explore the potential involvement of ALKBH5 in osteosarcoma and decipher the underlying cellular/molecular mechanisms. We discovered downregulated levels of demethylase ALKBH5 were correlated with increased m⁶A methylation in osteosarcoma cells/tissues compared with normal osteoblasts cells/tissues. ALKBH5 overexpression significantly suppressed osteosarcoma cell growth, migration, invasion, and trigged cell apoptosis. In contrast, inhibition of ALKBH5 produced the opposite effects. Whereas ALKBH5 silence enhanced m⁶A methylations of pre-miR-181b-1 and YAP-mRNA exerting oncogenic functions in osteosarcoma. Moreover, upregulation of YAP or downregulation of mature miR-181b-5p displayed a remarkable attenuation of anti-tumor activities caused by ALKBH5. Further results revealed that m⁶A methylated pre-miR-181b-1 was subsequently recognized by m⁶A-binding protein YTHDF2 to mediate RNA degradation. However, methylated YAP transcripts were recognized by YTHDF1 to promote its translation. Therefore, ALKBH5-based m⁶A demethylation suppressed osteosarcoma cancer progression through m⁶A-based direct/indirect regulation of YAP. Thus, ALKBH5 overexpression might be considered a new approach of replacement therapy for osteosarcoma treatment.

ALKBH5 是基于m ⁶ A 的 RNA 去甲基化的主要酶，它与许多生物学和病理生理过程有关。在这里，我们旨在探索 ALKBH5 在骨肉瘤中的潜在参与，并破译潜在的细胞/分子机制。我们发现与正常成骨细胞/组织相比，去甲基化酶 ALKBH5 的下调水平与骨肉瘤细胞/组织中m ⁶ A 甲基化的增加相关。ALKBH5 过表达显着抑制骨肉瘤细胞的生长、迁移、侵袭和触发细胞凋亡。相反，抑制 ALKBH5 产生了相反的效果。而 ALKBH5 沉默增强了 m ⁶在骨肉瘤中发挥致癌功能的 pre-miR-181b-1 和 YAP-mRNA 的甲基化。此外，YAP 的上调或成熟 miR-181b-5p 的下调显示出由 ALKBH5 引起的抗肿瘤活性的显着减弱。进一步的结果表明，m ⁶ A 甲基化的 pre-miR-181b-1 随后被 m ⁶ A 结合蛋白 YTHDF2 识别以介导 RNA 降解。然而，甲基化的 YAP 转录本被 YTHDF1 识别以促进其翻译。因此，基于 ALKBH5 的 m ⁶ A 去甲基化通过基于m ⁶ A 的直接/间接调节 YAP抑制骨肉瘤癌症进展。因此，ALKBH5 过表达可能被认为是治疗骨肉瘤的一种新的替代疗法。