Gerhard-Domagk-Institute of Pathology, Münster University Hospital, Münster, Germany.
Division of Translational Medical Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
Clin Cancer Res. 2024 Nov 1;30(21):4974-4986. doi: 10.1158/1078-0432.CCR-24-1152.
The pathognomonic FUS::DDIT3 fusion protein drives myxoid liposarcoma (MLS) tumorigenesis via aberrant transcriptional activation of oncogenic signaling. As FUS::DDIT3 has so far not been pharmacologically tractable to selectively target MLS cells, this study investigated the functional role of the cell cycle regulator WEE1 as novel FUS::DDIT3-dependent therapeutic vulnerability in MLS.
Immunohistochemical evaluation of the cell cycle regulator WEE1 was performed in a large cohort of MLS specimens. FUS::DDIT3 dependency and biological function of the G1/S cell cycle checkpoint were analyzed in a mesenchymal stem cell model and liposarcoma cell lines in vitro. WEE1 activity was modulated by RNAi-mediated knockdown and the small molecule inhibitor MK-1775 (adavosertib). An established MLS cell line-based chicken chorioallantoic membrane model was employed for in vivo confirmation.
We demonstrate that enhanced WEE1 pathway activity represents a hallmark of FUS::DDIT3-expressing cell lines as well as MLS tissue specimens and that WEE1 is required for MLS cellular survival in vitro and in vivo. Pharmacologic inhibition of WEE1 activity results in DNA damage accumulation and cell cycle progression forcing cells to undergo apoptotic cell death. In addition, our results uncover FUS::DDIT3-dependent WEE1 expression as an oncogenic survival mechanism to tolerate high proliferation and resulting replication stress in MLS. Fusion protein-driven G1/S cell cycle checkpoint deregulation via overactive Cyclin E/CDK2 complexes thereby contributes to enhanced WEE1 inhibitor sensitivity in MLS.
Our preclinical study identifies WEE1-mediated replication stress tolerance as molecular vulnerability in FUS::DDIT3-driven MLS tumorigenesis that could represent a novel target for therapeutic intervention.
特征性 FUS::DDIT3 融合蛋白通过异常转录激活致癌信号驱动黏液样脂肪肉瘤（MLS）的肿瘤发生。由于 FUS::DDIT3 迄今为止尚未在药理学上具有可操作性以选择性靶向 MLS 细胞，因此本研究探讨了细胞周期调节剂 WEE1 作为新型 FUS::DDIT3 依赖性治疗脆弱性在 MLS 中的功能作用。
对大量 MLS 标本中的细胞周期调节剂 WEE1 进行免疫组织化学评估。在间充质干细胞模型和脂肪肉瘤细胞系中体外分析 FUS::DDIT3 依赖性和 G1/S 细胞周期检查点的生物学功能。通过 RNAi 介导的敲低和小分子抑制剂 MK-1775（adavosertib）调节 WEE1 活性。采用已建立的 MLS 细胞系为基础的鸡胚绒毛尿囊膜模型进行体内验证。
我们证明增强的 WEE1 途径活性是表达 FUS::DDIT3 的细胞系以及 MLS 组织标本的标志，并且 WEE1 是 MLS 细胞在体外和体内存活所必需的。WEE1 活性的药理抑制导致 DNA 损伤积累和细胞周期进展，迫使细胞经历凋亡性细胞死亡。此外，我们的结果揭示了 FUS::DDIT3 依赖性 WEE1 表达作为一种致癌生存机制，以耐受 MLS 中的高增殖和由此产生的复制应激。融合蛋白驱动的 G1/S 细胞周期检查点失调通过过度活跃的 Cyclin E/CDK2 复合物导致在 MLS 中增强对 WEE1 抑制剂的敏感性。
我们的临床前研究确定了 WEE1 介导的复制应激耐受作为 FUS::DDIT3 驱动的 MLS 肿瘤发生中的分子脆弱性，这可能代表治疗干预的新靶标。
