Yan Jiangyu, Bu Lingli, Wang Yingsha, Yao Haojun, Li Guorui, Zheng Kewei, Huang Jing
State Key Laboratory of Chemo and Biosensing, School of Biomedical Sciences, Hunan University, Changsha 410082, China.
Hunan Key Laboratory of Animal Models and Molecular Medicine, Hunan University, Changsha 410082, Hunan Province, China.
Nucleic Acids Res. 2025 Jun 20;53(12). doi: 10.1093/nar/gkaf543.
G-quadruplexes (G4s) are noncanonical DNA structures that play key roles in regulating replication, transcription, and genome stability. Here, we investigate the effects of pyridine-bis(benzimidazole) (PyBI), a selective parallel and hybrid G4 stabilizer, on genome stability in cells. Biophysical and biochemical assays confirm PyBI's strong affinity for parallel G4s, leading to replication fork stalling and transcriptional repression of G4-associated oncogenes. Cleavage under targets and tagmentation (CUT&Tag) sequencing reveals a PyBI-induced genome-wide increase in G4 peaks, particularly at promoter and transcription start site regions. This G4 induction and stabilization triggers replication stress, G2/M arrest, and apoptosis. DNA repair pathway profiling shows that PyBI-induced G4 stabilization activates both homologous recombination and nonhomologous end joining (NHEJ), with a predominant role for NHEJ, as indicated by higher 53BP1 colocalization at G4 sites. Genome-wide mapping of PyBI-induced DNA breaks further supports a direct link between G4 stabilization and DNA damage. Moreover, PyBI shows synthetic lethality in DNA repair-deficient contexts, highlighting its therapeutic potential. These findings provide mechanistic insights into the genotoxic effects of PyBI and highlight its potential as a novel anticancer agent targeting G4-mediated genome instability.
G-四链体（G4s）是一种非经典DNA结构，在调节复制、转录和基因组稳定性方面发挥着关键作用。在此，我们研究了选择性平行和混合G4稳定剂吡啶双（苯并咪唑）（PyBI）对细胞基因组稳定性的影响。生物物理和生化分析证实了PyBI对平行G4s具有很强的亲和力，导致复制叉停滞以及G4相关癌基因的转录抑制。靶向切割和转座酶可及染色质测序（CUT&Tag）显示，PyBI诱导全基因组G4峰增加，尤其是在启动子和转录起始位点区域。这种G4诱导和稳定引发了复制应激、G2/M期阻滞和细胞凋亡。DNA修复途径分析表明，PyBI诱导的G4稳定激活了同源重组和非同源末端连接（NHEJ），其中NHEJ起主要作用，这在G4位点处53BP1更高的共定位中得到体现。全基因组范围内对PyBI诱导的DNA断裂进行定位，进一步支持了G4稳定与DNA损伤之间的直接联系。此外，PyBI在DNA修复缺陷的情况下表现出合成致死性，突出了其治疗潜力。这些发现为PyBI的遗传毒性作用提供了机制上的见解，并突出了其作为一种靶向G4介导的基因组不稳定的新型抗癌药物的潜力。
