Co-Inhibition of the DNA Damage Response and CHK1 Enhances Apoptosis of Neuroblastoma Cells
Co-Inhibition of the DNA Damage Response and CHK1 Enhances Apoptosis of Neuroblastoma Cells
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DOI：
10.3390/ijms20153700
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发表时间：
2019-08-01
影响因子：
5.6
通讯作者：
Makishima, Makoto
中科院分区：
文献类型：
--
作者：
Ando, Kiyohiro;Nakamura, Yohko;Makishima, Makoto
检验点蛋白1是S和G2/M细胞周期检验点DNA损伤反应的中心调节因子，在维持基因组完整性方面起着至关重要的作用。Chk1的过度表达被认为与癌症的侵袭性有关，该激酶的几种选择性抑制剂正在临床开发中，用于治疗各种癌症，包括神经母细胞瘤(NB)。在这里，我们检测了MYCN扩增的NB细胞系对CHK1抑制剂PF-477736的敏感性，并探索了提高其疗效的机制。PF-477736处理两个敏感的NB细胞系SMS-SAN和CHP134后，两种促凋亡蛋白Bax和PUMA的表达增加，为CHK1抑制剂的作用提供了机制。相反，在NB-39-nu和SK-N-BE细胞系中，PF-477736诱导DNA双链断裂，并激活共济失调毛细血管扩张突变丝氨酸/苏氨酸激酶(ATM)-P53-p21轴，这使得细胞对CHK1抑制剂的抗增殖作用相对不敏感。有趣的是，PF-477736和ATM抑制剂Ku55933联合处理克服了NB-39-nu和SK-N-BE细胞对CHK1抑制的不敏感性，并诱导了有丝分裂细胞死亡。同样，与PF-477736和NU7441共同处理，使细胞对CHK1抑制变得敏感。NU7441是DNA-PK的一种药理抑制剂，也是DDR途径的关键。综上所述，我们的结果表明，CHK1抑制剂和DDR之间的合成致死性驱动G2/M检查点的消除，并可能成为一种新的潜在的NB治疗策略。
Checkpoint kinase 1 (CHK1) is a central mediator of the DNA damage response (DDR) at the S and G2/M cell cycle checkpoints, and plays a crucial role in preserving genomic integrity. CHK1 overexpression is thought to contribute to cancer aggressiveness, and several selective inhibitors of this kinase are in clinical development for various cancers, including neuroblastoma (NB). Here, we examined the sensitivity of MYCN-amplified NB cell lines to the CHK1 inhibitor PF-477736 and explored mechanisms to increase its efficacy. PF-477736 treatment of two sensitive NB cell lines, SMS-SAN and CHP134, increased the expression of two pro-apoptotic proteins, BAX and PUMA, providing a mechanism for the effect of the CHK1 inhibitor. In contrast, in NB-39-nu and SK-N-BE cell lines, PF-477736 induced DNA double-strand breaks and activated the ataxia telangiectasia mutated serine/threonine kinase (ATM)-p53-p21 axis of the DDR pathway, which rendered the cells relatively insensitive to the antiproliferative effects of the CHK1 inhibitor. Interestingly, combined treatment with PF-477736 and the ATM inhibitor Ku55933 overcame the insensitivity of NB-39-nu and SK-N-BE cells to CHK1 inhibition and induced mitotic cell death. Similarly, co-treatment with PF-477736 and NU7441, a pharmacological inhibitor of DNA-PK, which is also essential for the DDR pathway, rendered the cells sensitive to CHK1 inhibition. Taken together, our results suggest that synthetic lethality between inhibitors of CHK1 and the DDR drives G2/M checkpoint abrogation and could be a novel potential therapeutic strategy for NB.