PO.ET05.01 · 实验与分子治疗
内切核酸酶FEN1抑制在神经母细胞瘤中的疗效机制
Mechanisms of efficacy of endonuclease FEN1 inhibition in neuroblastoma
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
背景：高危和复发性神经母细胞瘤（NB）患儿需要更好的疗法，而复发性细胞遗传学异常（如MYCN癌基因扩增）代表了候选治疗靶点。MYCN扩增和MYCN表达升高驱动失调的过度转录，导致NB肿瘤的发生和生长；MYCN扩增既可存在于线性基因组内（HSR），也可存在于环状染色体外DNA（ecDNA）上，与NB患儿显著更差的生存率相关。MYCN过表达与复制应激（RS）增加有关，而RS及随后的基因组不稳定性是肿瘤发生和进展的重要驱动因素。Flap内切核酸酶1（FEN1）是一种非必需的DNA复制酶，被鉴定为在BRCA1/2缺陷型癌症中通过诱导RS而发挥作用的合成致死靶点。近期使用复制酶抑制剂靶向RS升高癌症的成功，为靶向MYCN扩增型NB开辟了新途径。
方法：使用活细胞成像和细胞活力实验评估FEN1抑制的疗效，比较MYCN扩增型与非扩增型NB细胞、以及MYCN表达可诱导和可抑制的NB细胞中的结果。通过Western blot评估经FEN1抑制剂处理细胞的细胞死亡机制及对复制应激的影响。
结果：FEN1抑制对NB细胞有效，并且在MYCN扩增型NB细胞中显著更有效，导致细胞生长和活力降低。MYCN表达升高也导致对FEN1抑制的敏感性增加，而MYCN表达降低则降低敏感性。FEN1抑制导致凋亡的诱导，且对FEN1抑制的反应与复制应激标志物相关。
结论：我们发现MYCN扩增型NB细胞对FEN1抑制高度敏感，提示FEN1抑制可能是针对高危和复发性神经母细胞瘤患儿的一种有前景的治疗策略。
查看英文原文 English abstract
Background: Children with high-risk and relapsed neuroblastoma (NB) need improved therapies, and recurrent cytogenetic abnormalities, such as MYCN oncogene amplification, represent candidate therapeutic targets. MYCN amplification and increased MYCN expression drive deregulated hyper-transcription that leads to development and growth of NB tumors, and MYCN amplifications, which can be found both within the linear genome (HSR) and on circular extrachromosomal DNA (ecDNA), are associated with significantly worse survival rates for children with NB. MYCN overexpression has been linked to an increase in replication stress (RS), and RS and subsequent genome instability are important drivers of tumor initiation and progression. Flap Endonuclease 1 (FEN1), a non-essential DNA replication enzyme, was identified as a synthetic lethal target in BRCA1/2-deficient cancers via induction of RS. Recent success of targeting RS-elevated cancers with replication enzyme inhibitors opens a new avenue to target MYCN-amplified NB.
Methods: The efficacy of FEN1 inhibition was assessed using live cell imaging and cell viability assays, comparing results in MYCN-amplified to -nonamplified NB cells and in NB cells with inducible MYCN expression and repression. Mechanisms of cell death and impacts on replication stress in cells treated with FEN1 inhibitors were evaluated by Western blots.
Results: FEN1 inhibition was effective against NB cells and was significantly more effective in MYCN-amplified NB cells causing reduced cell growth and viability. Increased MYCN expression also led to increased sensitivity to FEN1 inhibition, and reduced MYCN expression reduced sensitivity. FEN1 inhibition led to the induction of apoptosis and responses to FEN1 inhibition were associated with markers of replication stress.
Conclusions: We have discovered that MYCN-amplified NB cells are hypersensitive to FEN1 inhibition, suggesting that FEN1 inhibition may be a promising therapeutic strategy for children with high-risk and relapsed neuroblastoma.
利益披露 Disclosure
C. S. Sampaio, None..
E. Wu, None..
M. Cinelli, None..
E. Steen, None..
A. Shiau, None..
R. Kolodner, None..
J. Wang, None..
P. E. Zage, None.