Keane Simon, de Weerd Hendrik A, Ejeskär Katarina
Translational Medicine, DHEAR, School of Health Sciences, University of Skövde, Skövde, Sweden.
School of Bioscience, Systems biology research center, University of Skövde, Skövde, Sweden.
DNA Repair (Amst). 2022 Apr;112:103302. doi: 10.1016/j.dnarep.2022.103302. Epub 2022 Feb 17.
In primary neuroblastoma, deletions on chromosome 11q are known to result in an increase in the total number of chromosomal breaks. The DNA double-strand break repair pathways mediated by NHEJ are often upregulated in cancer. DLG2, a candidate tumor suppressor gene on chromosome 11q, has previously been implicated in DNA repair.
We evaluated an association between gene expression and neuroblastoma patient outcome, risk categorization, and 11q status using publicly available microarray data from independent neuroblastoma patient datasets. Functional studies were conducted using comet assay and H2AX phosphorylation in neuroblastoma cell lines and in the fruit fly with UVC-induced DNA breaks.
We show that the NHEJ genes PARP1 and FEN1 are over expressed in neuroblastoma and restoration of DLG2 impairs their gene and protein expression. When exposed to UVC radiation, cells with DLG2 over expression show less DNA fragmentation and induce apoptosis in a p53 S46 dependent manner. We could also confirm that DLG2 over expression results in CHK1 phosphorylation consistent with previous reports of G2/M maintenance.
Taken together, we show that DLG2 over expression increases p53 mediated apoptosis in response to etoposide and UVC mediated genotoxicity and reduced DNA replication machinery.
在原发性神经母细胞瘤中，已知11q染色体缺失会导致染色体断裂总数增加。由非同源末端连接（NHEJ）介导的DNA双链断裂修复途径在癌症中通常会上调。DLG2是11q染色体上的一个候选肿瘤抑制基因，先前已被证明与DNA修复有关。
我们使用来自独立神经母细胞瘤患者数据集的公开可用微阵列数据，评估了基因表达与神经母细胞瘤患者预后、风险分类和11q状态之间的关联。使用彗星试验和H2AX磷酸化在神经母细胞瘤细胞系和经紫外线（UVC）诱导DNA断裂的果蝇中进行功能研究。
我们发现NHEJ基因PARP1和FEN1在神经母细胞瘤中过度表达，DLG2的恢复会损害它们的基因和蛋白质表达。当暴露于UVC辐射时，DLG2过表达的细胞显示出较少的DNA片段化，并以p53 S46依赖性方式诱导凋亡。我们还可以证实，DLG2过表达导致CHK1磷酸化，这与先前关于G2/M期维持的报道一致。
综上所述，我们表明DLG2过表达会增加依托泊苷和UVC介导的基因毒性以及DNA复制机制减少时p53介导的凋亡。
