In this study, we explored the therapeutic potential of everolimus, an mTOR inhibitor, in a patient-derived xenograft (PDX) of rhabdomyosarcoma, the most prevalent malignant pediatric sarcoma. Additionally, rhabdoid tumor cell line A-204 and Ewings sarcoma cell line A-673 were cultured to assess the in vitro effect of everolimus. Furthermore, the cell-derived xenograft (CDX) of A-673 was established and treated with everolimus in vivo. Immunohistochemistry and western blotting were performed to detect the expressions of pertinent proteins. Results showed that everolimus intervention had limited inhibitory effect on PDX tumor growth compared to cyclophosphamide. Nevertheless, everolimus treatment significantly influenced the phosphorylation levels of S6 kinase beta 1 (S6K1) and eIF4E-binding protein 1 (p-4E-BP1), resulting in the inhibition of angiogenesis in vitro and in vivo. Interestingly, everolimus led to an up-regulation in the level of interleukin (IL)-17A in sarcoma cells. Notably, when secukinumab, a monoclonal antibody of IL-17A, was combined with everolimus, it synergistically enhanced the inhibitory effect of everolimus on sarcoma cell proliferation in vitro and on the growth of PDX or CDX xenograft tumors in vivo. Importantly, this combination therapy did not affect the mTOR signaling. These results indicate that everolimus exerts an anti-pediatric sarcomas effect by inhibiting mTOR signal. However, everolimus induces sarcoma cells to produce IL-17A, which promotes tumor cell survival and counteracts its anti-pediatric sarcomas effect. The combination of secukinumab effectively eliminates the effects of IL-17A, thereby improving the therapeutic efficacy of everolimus in the context of pediatric sarcomas.

中文翻译：

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通过靶向 IL-17A 增强依维莫司联合苏金单抗的抗儿童肉瘤作用

在这项研究中，我们探讨了依维莫司（一种 mTOR 抑制剂）在患者来源的横纹肌肉瘤（最常见的恶性小儿肉瘤）异种移植物 (PDX) 中的治疗潜力。此外，培养横纹肌样肿瘤细胞系A-204和尤文氏肉瘤细胞系A-673以评估依维莫司的体外效果。此外，建立了 A-673 的细胞源异种移植物 (CDX)，并在体内用依维莫司进行处理。进行免疫组织化学和蛋白质印迹来检测相关蛋白的表达。结果显示，与环磷酰胺相比，依维莫司干预对 PDX 肿瘤生长的抑制作用有限。然而，依维莫司治疗显着影响 S6 激酶 β 1 (S6K1) 和 eIF4E 结合蛋白 1 (p-4E-BP1) 的磷酸化水平，从而抑制体外和体内血管生成。有趣的是，依维莫司导致肉瘤细胞中白细胞介素 (IL)-17A 水平上调。值得注意的是，当IL-17A单克隆抗体苏金单抗与依维莫司联合使用时，协同增强依维莫司对体外肉瘤细胞增殖和体内PDX或CDX异种移植肿瘤生长的抑制作用。重要的是，这种联合疗法并不影响 mTOR 信号传导。这些结果表明依维莫司通过抑制 mTOR 信号发挥抗儿童肉瘤作用。然而，依维莫司诱导肉瘤细胞产生IL-17A，从而促进肿瘤细胞存活并抵消其抗儿童肉瘤作用。苏金单抗联合用药可有效消除 IL-17A 的影响，从而提高依维莫司治疗小儿肉瘤的疗效。