Wang Siyuan, Xia Yu, Huang Pu, Xu Cheng, Qian Yiyu, Fang Tian, Gao Qinglei
Cancer Biology Research Center (Key Laboratory of Chinese Ministry of Education), Tongji Hospital Tongji Medical College Huazhong University of Science and Technology, 1095 Jiefang Ave, Wuhan 430030, China.
Department of Gynecology and Obstetrics, Tongji Hospital Tongji Medical College Huazhong University of Science and Technology, Wuhan 430030, China.
J Oncol. 2023 Feb 6;2023:1453739. doi: 10.1155/2023/1453739. eCollection 2023.
Breast and ovarian cancers are common malignancies among women, contributing to a significant disease burden, and are characterized by a high level of genomic instability, owing to the failure of homologous recombination repair (HRR). Pharmacological inhibition of poly(ADP-ribose) polymerase (PARP) could elicit the synthetic lethal effect of tumor cells in patients with homologous recombination deficiency, ultimately achieving a favorable clinical benefit. However, primary and acquired resistance remain the greatest hurdle, limiting the efficacy of PARP inhibitors; thus, strategies conferring or augmenting tumor cell sensitivity to PARP inhibitors are urgently required.
Our RNA-seq data of niraparib-treated and -untreated tumor cells were analyzed by R language. Gene Set Enrichment Analysis (GSEA) was applied to assess the biological functions of GTP cyclohydrolase 1 (GCH1). Quantitative real-time PCR, Western blotting, and immunofluorescence were applied to confirm the upregulation of GCH1 upon niraparib treatment at transcriptional and translational levels. Immunohistochemistry of patient-derived xenograft (PDX)-derived tissue sections further validated that niraparib increased GCH1 expression. Tumor cell apoptosis was detected by flow cytometry, while the superiority of the combination strategy was confirmed in the PDX model.
The expression of GCH1 was aberrantly enriched in breast and ovarian cancers and increased after niraparib treatment via JAK-STAT signaling. GCH1 was also demonstrated to be associated with the HRR pathway. Subsequently, the enhancement of the tumor-killing effect of PARP inhibitors induced by GCH1 suppression using siRNA and GCH1 inhibitor was validated by flow cytometry in vitro. Finally, using the PDX model, we further demonstrated that GCH1 inhibitors markedly potentiated PARP inhibitors' antitumor efficacy in vivo.
Our results illustrated that PARP inhibitors promote GCH1 expression via the JAK-STAT pathway. We also elucidated the potential relationship between GCH1 and the homologous recombination repair pathway and proposed a combination regimen of GCH1 suppression with PARP inhibitors in breast and ovarian cancers.
乳腺癌和卵巢癌是女性常见的恶性肿瘤，造成了重大的疾病负担，其特征是由于同源重组修复（HRR）功能缺陷导致高水平的基因组不稳定。聚（ADP - 核糖）聚合酶（PARP）的药理学抑制可在同源重组缺陷患者中引发肿瘤细胞的合成致死效应，最终实现良好的临床效益。然而，原发性和获得性耐药仍然是最大的障碍，限制了PARP抑制剂的疗效；因此，迫切需要赋予或增强肿瘤细胞对PARP抑制剂敏感性的策略。
我们用R语言分析了经尼拉帕利处理和未处理的肿瘤细胞的RNA测序数据。基因集富集分析（GSEA）用于评估鸟苷三磷酸环化水解酶1（GCH1）的生物学功能。采用定量实时PCR、蛋白质免疫印迹和免疫荧光技术在转录和翻译水平上证实尼拉帕利处理后GCH1的上调。患者来源异种移植（PDX）组织切片的免疫组织化学进一步验证了尼拉帕利可增加GCH1表达。通过流式细胞术检测肿瘤细胞凋亡，同时在PDX模型中证实联合策略的优势。
GCH1的表达在乳腺癌和卵巢癌中异常富集，并且在尼拉帕利处理后通过JAK - STAT信号通路增加。GCH1也被证明与HRR途径相关。随后，通过体外流式细胞术验证了使用小干扰RNA（siRNA）和GCH1抑制剂抑制GCH1诱导的PARP抑制剂杀瘤效果增强。最后，使用PDX模型，我们进一步证明GCH1抑制剂在体内显著增强了PARP抑制剂的抗肿瘤疗效。
我们的结果表明PARP抑制剂通过JAK - STAT途径促进GCH1表达。我们还阐明了GCH1与同源重组修复途径之间的潜在关系，并提出了在乳腺癌和卵巢癌中联合抑制GCH1与PARP抑制剂的方案。
