Abstract

Purpose

MYC-driven medulloblastomas are highly aggressive childhood tumors with dismal outcomes and a lack of new treatment paradigms. We identified that targeting replication stress through WEE1 inhibition to suppress the S-phase replication checkpoint, combined with the attenuation of nucleotide synthesis with gemcitabine, is an effective strategy to induce apoptosis in MYC-driven medulloblastoma that could be rapidly translated into early phase clinical trials in children. Attenuation of replication stress is a key component of MYC-driven oncogenesis. Previous studies revealed a vulnerability in MYC medulloblastoma through WEE1 inhibition. Here, we focused on elucidating combinations of agents to synergize with WEE1 inhibition and drive replication stress toward cell death.

Methods

We first analyzed WEE1 expression in patient tissues by immunohistochemistry. Next, we used high-throughput drug screens to identify agents that would synergize with WEE1 inhibition. Synergy was confirmed by in vitro live cell imaging, ex vivo slice culture models, and in vivo studies using orthotopic and flank xenograft models.

Results

WEE1 expression was significantly higher in Group 3 and 4 medulloblastoma patients. The WEE1 inhibitor AZD1775 synergized with inhibitors of nucleotide synthesis, including gemcitabine. AZD1775 with gemcitabine suppressed proliferation and induced apoptosis. Ex vivo modeling demonstrated efficacy in Group 3 medulloblastoma patients, and in vivo modeling confirmed that combining AZD1775 and gemcitabine effectively suppressed tumor growth.

Conclusion

Our results identified a potent new synergistic treatment combination for MYC-driven medulloblastoma that warrants exploration in early phase clinical trials.

中文翻译：

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用AZD1775和吉西他滨靶向髓母细胞瘤中MYC驱动的复制应激。

摘要

目的

MYC驱动的成神经细胞母细胞瘤是高度侵袭性的儿童期肿瘤，预后不佳，缺乏新的治疗方法。我们发现通过WEE1抑制靶向复制应激以抑制S期复制检查点，并与吉西他滨减弱核苷酸合成相结合，是诱导MYC驱动的髓母细胞瘤细胞凋亡的有效策略，可以迅速转化为早期临床试验在儿童中。复制压力的减弱是MYC驱动的肿瘤发生的关键组成部分。先前的研究揭示了通过WEE1抑制可导致MYC髓母细胞瘤的脆弱性。在这里，我们集中于阐明与WEE1抑制协同作用并驱动复制应激导致细胞死亡的药物组合。

方法

我们首先通过免疫组织化学分析了患者组织中WEE1的表达。接下来，我们使用高通量药物筛选来确定可与WEE1抑制协同作用的药物。通过体外活细胞成像，离体切片培养模型以及使用原位和侧面异种移植模型的体内研究，证实了协同作用。

结果

在第3组和第4组髓母细胞瘤患者中，WEE1表达明显更高。WEE1抑制剂AZD1775与核苷酸合成抑制剂（包括吉西他滨）协同作用。吉西他滨的AZD1775抑制增殖并诱导凋亡。离体模型在第3组髓母细胞瘤患者中证明了疗效，并且体内模型证实了AZD1775和吉西他滨的联合有效抑制了肿瘤的生长。

结论

我们的结果为MYC驱动的成神经细胞母细胞瘤确定了一种有效的新型协同治疗组合，值得在早期临床试验中进行探索。