铁死亡（Ferroptosis）是一种依赖于铁离子的脂质过氧化驱动的程序化细胞死亡，与癌症治疗密切相关。开发可药用的铁死亡诱导剂及其合理应用于癌症治疗非常重要。在此，我们通过大规模药物筛选发现HDAC6抑制剂Tubastatin A是一种新型可药用的铁死亡诱导剂。Tubastatin A通过生物素连接的抑制剂和LC/MS分析直接结合到GPX4，并抑制GPX4酶活性，这与其抑制HDAC6无关。此外，我们的研究结果表明，放疗不仅活化Nrf2介导的GPX4转录，还抑制溶酶体介导的GPX4降解，进而诱导癌细胞对铁死亡的耐受性和放射性耐受性。Tubastatin A通过抑制GPX4酶活性克服了癌细胞的抗铁死亡和放射性耐受性。更重要的是，Tubastatin A具有卓越的生物利用度，如其在小鼠异种移植模型中显著促进放疗诱导的脂质过氧化和抑制肿瘤生长的表现。我们的研究结果发现，Tubastatin A是一种新型的可药用的铁死亡诱导剂，可增强放疗介导的抗肿瘤效果。这项研究为Tubastatin A的临床评估提供了强有力的理由，特别是在与放疗联合使用时。版权所有©2023作者。Elsevier B.V.保留所有权利。

Ferroptosis, an iron-dependent lipid peroxidation-driven programmed cell death, is closely related to cancer therapy. The development of druggable ferroptosis inducers and their rational application in cancer therapy are critical. Here, we identified Tubastatin A, an HDAC6 inhibitor as a novel druggable ferroptosis inducer through large-scale drug screening. Tubastatin A directly bonded to GPX4 and inhibited GPX4 enzymatic activity through biotin-linked Tubastatin A putdown and LC/MS analysis, which is independent of its inhibition of HDAC6. In addition, our results showed that radiotherapy not only activated Nrf2-mediated GPX4 transcription but also inhibited lysosome-mediated GPX4 degradation, subsequently inducing ferroptosis tolerance and radioresistance in cancer cells. Tubastatin A overcame ferroptosis resistance and radioresistance of cancer cells by inhibiting GPX4 enzymatic activity. More importantly, Tubastatin A has excellent bioavailability, as demonstrated by its ability to significantly promote radiotherapy-induced lipid peroxidation and tumour suppression in a mouse xenograft model. Our findings identify a novel druggable ferroptosis inducer, Tubastatin A, which enhances radiotherapy-mediated antitumor effects. This work provides a compelling rationale for the clinical evaluation of Tubastatin A, especially in combination with radiotherapy.Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.