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Abstract：
Radiotherapy is the primary treatment for patients with nasopharyngeal carcinoma (NPC); however, almost 20% of patients experience treatment failure due to radioresistance. Therefore, understanding the mechanisms of radioresistance is imperative. HOTAIRM1 is deregulated in various human cancers, yet its role in NPC radioresistance are largely unclear.
This study investigated the association between HOTAIRM1 and radioresistance using CCK8, flow cytometry, and comet assays. Additionally, xenograft mice and patient-derived xenografts (PDX) models were employed to elucidate the biological functions of HOTAIRM1, and transcriptomic RNA sequencing was utilized to identify its target genes.
Our study revealed an upregulation of HOTAIRM1 levels in radioresistant NPC cell lines and tissues. Furthermore, a positive correlation was noted between high HOTAIRM1 expression and increased NPC cell proliferation, reduced apoptosis, G2/M cell cycle arrest, and diminished cellular DNA damage following radiotherapy. HOTAIRM1 modulates the acetylation and stability of the FTO protein, and inhibiting FTO elevates the m6A methylation level of CD44 precursor transcripts in NPC cells. Additionally, silencing the m6A reading protein YTHDC1 was found to increase the expression of CD44V. HOTAIRM1 enhances NPC cell resistance to ferroptosis and irradiation through the HOTAIRM1-FTO-YTHDC1-CD44 axis. Mechanistically, HOTAIRM1 interacts with the FTO protein and induces m6A demethylation of the CD44 transcript. The absence of m6A modification in the CD44 transcript prevents its recognition by YTHDC1, resulting in the transition from CD44S to CD44V. An abundance of CD44V suppresses ferroptosis induced by irradiation and contributes to NPC radioresistance.
In conclusion, the results in this study support the idea that HOTAIRM1 stimulates CD44 alternative splicing via FTO-mediated demethylation, thereby attenuating ferroptosis induced by irradiation and promoting NPC radioresistance.
This study investigated the association between HOTAIRM1 and radioresistance using CCK8, flow cytometry, and comet assays. Additionally, xenograft mice and patient-derived xenografts (PDX) models were employed to elucidate the biological functions of HOTAIRM1, and transcriptomic RNA sequencing was utilized to identify its target genes.
Our study revealed an upregulation of HOTAIRM1 levels in radioresistant NPC cell lines and tissues. Furthermore, a positive correlation was noted between high HOTAIRM1 expression and increased NPC cell proliferation, reduced apoptosis, G2/M cell cycle arrest, and diminished cellular DNA damage following radiotherapy. HOTAIRM1 modulates the acetylation and stability of the FTO protein, and inhibiting FTO elevates the m6A methylation level of CD44 precursor transcripts in NPC cells. Additionally, silencing the m6A reading protein YTHDC1 was found to increase the expression of CD44V. HOTAIRM1 enhances NPC cell resistance to ferroptosis and irradiation through the HOTAIRM1-FTO-YTHDC1-CD44 axis. Mechanistically, HOTAIRM1 interacts with the FTO protein and induces m6A demethylation of the CD44 transcript. The absence of m6A modification in the CD44 transcript prevents its recognition by YTHDC1, resulting in the transition from CD44S to CD44V. An abundance of CD44V suppresses ferroptosis induced by irradiation and contributes to NPC radioresistance.
In conclusion, the results in this study support the idea that HOTAIRM1 stimulates CD44 alternative splicing via FTO-mediated demethylation, thereby attenuating ferroptosis induced by irradiation and promoting NPC radioresistance.
摘要：
背景：放射治疗是鼻咽癌（NPC）患者的主要治疗方法；然而，近20％的患者由于放射抵抗而经历治疗失败。因此,了解辐射抗性的机制是必要的。HOTAIRM1在各种人类癌症中失调，然而，其在NPC放射抗性中的作用尚不清楚。
方法：本研究使用CCK8、流式细胞术、和彗星化验。此外,采用异种移植小鼠和患者来源的异种移植（PDX）模型来阐明HOTAIRM1的生物学功能，并利用转录组RNA测序来鉴定其靶基因。
结果：我们的研究揭示了耐放射性NPC细胞系和组织中HOTAIRM1水平的上调。此外，HOTAIRM1高表达与NPC细胞增殖增加之间呈正相关，减少细胞凋亡，G2/M细胞周期阻滞，放疗后细胞DNA损伤减少。HOTAIRM1调节FTO蛋白的乙酰化和稳定性，抑制FTO可提高NPC细胞中CD44前体转录本的m6A甲基化水平。此外,发现沉默m6A阅读蛋白YTHDC1可增加CD44V的表达。HOTAIRM1通过HOTAIRM1-FTO-YTHDC1-CD44轴增强NPC细胞对铁凋亡和辐射的抗性。机械上,HOTAIRM1与FTO蛋白相互作用并诱导CD44转录物的m6A去甲基化。CD44转录物中m6A修饰的缺失阻止了其被YTHDC1识别,导致从CD44S转变为CD44V。大量的CD44V抑制了由辐照引起的铁中毒，并有助于NPC放射抗性。
结论：结论：这项研究的结果支持HOTAIRM1通过FTO介导的去甲基化刺激CD44选择性剪接，从而减弱辐射诱导的铁中毒并促进NPC辐射抗性。
方法：本研究使用CCK8、流式细胞术、和彗星化验。此外,采用异种移植小鼠和患者来源的异种移植（PDX）模型来阐明HOTAIRM1的生物学功能，并利用转录组RNA测序来鉴定其靶基因。
结果：我们的研究揭示了耐放射性NPC细胞系和组织中HOTAIRM1水平的上调。此外，HOTAIRM1高表达与NPC细胞增殖增加之间呈正相关，减少细胞凋亡，G2/M细胞周期阻滞，放疗后细胞DNA损伤减少。HOTAIRM1调节FTO蛋白的乙酰化和稳定性，抑制FTO可提高NPC细胞中CD44前体转录本的m6A甲基化水平。此外,发现沉默m6A阅读蛋白YTHDC1可增加CD44V的表达。HOTAIRM1通过HOTAIRM1-FTO-YTHDC1-CD44轴增强NPC细胞对铁凋亡和辐射的抗性。机械上,HOTAIRM1与FTO蛋白相互作用并诱导CD44转录物的m6A去甲基化。CD44转录物中m6A修饰的缺失阻止了其被YTHDC1识别,导致从CD44S转变为CD44V。大量的CD44V抑制了由辐照引起的铁中毒，并有助于NPC放射抗性。
结论：结论：这项研究的结果支持HOTAIRM1通过FTO介导的去甲基化刺激CD44选择性剪接，从而减弱辐射诱导的铁中毒并促进NPC辐射抗性。
