Offenbacher Rachel, Jackson Kyle W, Hayashi Masanori, Zhang Jinghang, Peng Da, Tan Yuqi, Stewart Tracy Murray, Ciero Paul, Foley Jackson, Casero Robert A, Cahan Patrick, Loeb David M
bioRxiv. 2024 Jun 17:2024.06.14.599064. doi: 10.1101/2024.06.14.599064.
Polyamine metabolism and signaling play important roles in multiple cancers but have not previously been studied in Ewing sarcoma. Here, we show that blocking polyamine synthesis with D, L-alpha-difluoromethylornithine (DFMO) causes a G1 cell cycle arrest, dose-dependent decreases in sarcosphere formation from Ewing sarcoma cell lines growing in non-adherent conditions and a decrease in clonogenic growth in soft agar. Further, we utilized our orthotopic implantation/amputation model of Ewing sarcoma metastasis to demonstrate that DFMO slowed primary tumor growth in addition to limiting metastasis. RNA sequencing demonstrated gene expression patterns consistent with induction of ferroptosis caused by polyamine depletion. Induction of ferroptosis was validated in vitro by demonstrating that ferrostatin-1, an inhibitor of ferroptosis, allows sphere formation even in the presence of DFMO. Collectively, these results reveal a novel mechanism by which DFMO prevents metastasis - induction of ferroptosis due to polyamine depletion. Our results provide preclinical justification to test the ability of DFMO to prevent metastatic recurrence in Ewing sarcoma patients at high risk for relapse.
多胺代谢和信号传导在多种癌症中发挥重要作用，但此前尚未在尤因肉瘤中进行研究。在此，我们表明，用D，L-α-二氟甲基鸟氨酸（DFMO）阻断多胺合成会导致G1期细胞周期停滞，使非贴壁条件下生长的尤因肉瘤细胞系形成球状体的能力呈剂量依赖性下降，并降低软琼脂中的克隆形成生长。此外，我们利用尤因肉瘤转移的原位植入/截肢模型证明，DFMO除了限制转移外，还减缓了原发性肿瘤的生长。RNA测序显示的基因表达模式与多胺耗竭引起的铁死亡诱导一致。通过证明铁死亡抑制剂铁抑素-1即使在存在DFMO的情况下也能使球状体形成，在体外验证了铁死亡的诱导。总的来说，这些结果揭示了DFMO预防转移的一种新机制——多胺耗竭诱导铁死亡。我们的结果为测试DFMO预防尤因肉瘤高危复发患者转移复发的能力提供了临床前依据。
