Department of Biochemistry, College of Medicine, Ewha Womans University, Seoul 07804, Korea.
Department of Obstetrics and Gynecology, College of Medicine, Ewha Womans University, Seoul 07804, Korea.
BMB Rep. 2023 Jun;56(6):347-352. doi: 10.5483/BMBRep.2022-0202.
The protein family of poly (ADP-ribose) polymerases (PARPs) is comprised of multifunctional nuclear enzymes. Several PARP inhibitors have been developed as new anticancer drugs to combat resistance to chemotherapy. Herein, we characterized PARP4 mRNA expression profiles in cisplatin-sensitive and cisplatin-resistant ovarian cancer cell lines. PARP4 mRNA expression was significantly upregulated in cisplatin-resistant ovarian cancer cell lines, and this upregulation was associated with the hypomethylation of specific cytosine-phosphate-guanine (CpG) sites (cg18582260 and cg17117459) on its promoter. Reduced PARP4 expression was restored by treating cisplatin-sensitive cell lines with a demethylation agent, implicating the epigenetic regulation of PARP4 expression by promoter methylation. Depletion of PARP4 expression in cisplatin-resistant cell lines reduced cisplatin chemoresistance and promoted cisplatin-induced DNA fragmentation. The differential mRNA expression and DNA methylation status at specific PARP4 promoter CpG sites (cg18582260 and cg17117459) according to cisplatin responses, was further validated in primary ovarian tumor tissues. The results showed significantly increased PARP4 mRNA expressions and decreased DNA methylation levels at specific PARP4 promoter CpG sites (cg18582260 and cg17117459) in cisplatin-resistant patients. Additionally, the DNA methylation status at cg18582260 CpG sites in ovarian tumor tissues showed fairly clear discrimination between cisplatin-resistant patients and cisplatin-sensitive patients, with high accuracy (area under the curve = 0.86, P = 0.003845). Our findings suggest that the DNA methylation status of PARP4 at the specific promoter site (cg18582260) may be a useful diagnostic biomarker for predicting the response to cisplatin in ovarian cancer patients. [BMB Reports 2023; 56(6): 347-352].
多聚（ADP-核糖）聚合酶（PARP）蛋白家族由多功能核酶组成。几种 PARP 抑制剂已被开发为新型抗癌药物，以对抗化疗耐药性。在此，我们研究了顺铂敏感和耐药卵巢癌细胞系中 PARP4mRNA 的表达谱。PARP4mRNA 的表达在顺铂耐药的卵巢癌细胞系中显著上调，这种上调与启动子上特定胞嘧啶-磷酸-鸟嘌呤（CpG）位点（cg18582260 和 cg17117459）的低甲基化有关。用去甲基化剂处理顺铂敏感细胞系可恢复 PARP4 表达的降低，提示 PARP4 表达受启动子甲基化的表观遗传调控。在顺铂耐药细胞系中耗尽 PARP4 表达可降低顺铂的化疗耐药性并促进顺铂诱导的 DNA 断裂。根据顺铂反应，在特定 PARP4 启动子 CpG 位点（cg18582260 和 cg17117459）的差异 mRNA 表达和 DNA 甲基化状态在原发性卵巢肿瘤组织中得到进一步验证。结果显示，在顺铂耐药患者中，PARP4mRNA 表达显著增加，特定 PARP4 启动子 CpG 位点（cg18582260 和 cg17117459）的 DNA 甲基化水平降低。此外，卵巢肿瘤组织中 cg18582260CpG 位点的 DNA 甲基化状态在顺铂耐药患者和顺铂敏感患者之间具有相当清晰的区分，具有较高的准确性（曲线下面积=0.86，P=0.003845）。我们的研究结果表明，PARP4 在特定启动子位点（cg18582260）的 DNA 甲基化状态可能是预测卵巢癌患者对顺铂反应的有用诊断生物标志物。[BMB 报告 2023；56(6):347-352]。
