Saad Mona, Zhang Rongxin, Cucchiarini Anne, Mehawej Cybel, Mergny Jean-Louis, Mroueh Mohamad, Faour Wissam H
Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, Byblos, Lebanon.
Laboratoire d'Optique et Biosciences, Institut Polytechnique de Paris, CNRS, INSERM, Université Paris-Saclay, 91120, Palaiseau, France; State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China.
Biochimie. 2023 Nov;214(Pt A):45-56. doi: 10.1016/j.biochi.2023.08.014. Epub 2023 Sep 1.
The majority of drugs are metabolized by cytochrome P450 (CYP) enzymes, primarily belonging to the CYP1, CYP2 and CYP3 families. Genetic variations are the main cause of inter-individual differences in drug response, which constitutes a major concern in pharmacotherapy. G-quadruplexes (G4s), are non-canonical DNA and RNA secondary structures formed by guanine-rich sequences. G4s have been implicated in cancer and gene regulation. In this study, we investigated putative G4-forming sequences (PQSs) in the CYP genes. Our findings reveal a high density of PQSs in the full genes of CYP family 2. Moreover, we observe an increased density of PQSs in the promoters of CYP family 1 genes compared to non-CYP450 genes. Importantly, stable PQSs were also identified in all studied CYP genes. Subsequently, we assessed the impact of the most frequently reported genetic mutations in the selected genes and the possible effect of these mutations on G4 formation as well as on the thermodynamic stability of predicted G4s. We found that 4 SNPs overlap G4 sequences and lead to mutated DNA and RNA G4 forming sequences in their context. Notably, the mutation in the CYP2C9 gene, which is associated with impaired (S)-warfarin metabolism in patients, alters a G4 sequence. We then demonstrated that at least 10 of the 13 chosen cytochrome P450 G4 candidates form G-quadruplex structures in vitro, using a combination of spectroscopic methods. In conclusion, our findings indicate the potential role of G-quadruplexes in the regulation of cytochrome genes, and emphasize the importance of G-quadruplexes in drug metabolism.
大多数药物由细胞色素P450（CYP）酶代谢，这些酶主要属于CYP1、CYP2和CYP3家族。基因变异是药物反应个体差异的主要原因，这是药物治疗中的一个主要问题。G-四链体（G4s）是由富含鸟嘌呤的序列形成的非经典DNA和RNA二级结构。G4s与癌症和基因调控有关。在本研究中，我们调查了CYP基因中假定的G4形成序列（PQSs）。我们的研究结果显示，CYP2家族的完整基因中PQSs密度很高。此外，与非CYP450基因相比，我们观察到CYP1家族基因启动子中PQSs密度增加。重要的是，在所有研究的CYP基因中也鉴定出了稳定的PQSs。随后，我们评估了所选基因中最常报道的基因突变的影响，以及这些突变对G4形成以及预测G4s热力学稳定性的可能影响。我们发现4个单核苷酸多态性（SNPs）与G4序列重叠，并在其背景下导致DNA和RNA G4形成序列发生突变。值得注意的是，与患者体内（S）-华法林代谢受损相关的CYP2C9基因突变改变了一个G4序列。然后，我们使用多种光谱方法证明，在13个选定的细胞色素P450 G4候选物中，至少有10个在体外形成G-四链体结构。总之，我们的研究结果表明G-四链体在细胞色素基因调控中的潜在作用，并强调了G-四链体在药物代谢中的重要性。
