Department of Immunology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China.
Department of Clinical Laboratory, Hubei No. 3 People's Hospital of Jianghan University, No. 26 Zhongshan Avenue, Wuhan, 430033, Hubei, China.
J Cancer Res Clin Oncol. 2021 Aug;147(8):2239-2248. doi: 10.1007/s00432-021-03640-4. Epub 2021 May 26.
Targeted cancer therapy has shed light on the treatment of tumor, especially for patients with non-small cell lung cancer. However, only a limited portion of NSCLC patients carrying specific mutations showed an ideal drug response. In addition, DNA methylation status showed a great potential for cancer detection and prognosis prediction.
Bisulfite sequencing was performed to analyze the DNA methylation of WIF1 promoter in cfDNA and tumor tissue samples collected from NSCLC patients. PFS and OS analyses were carried out to evaluate the prognosis of gefitinib treatment in patients with differential levels of WIF1 DNA methylation. Quantitative real-time PCR was used to analyze the expression of WIF1 mRNA, while immunohistochemistry was performed to assess the expression of WIF1 protein. Furthermore, ELISA was carried out to evaluate the WIF1 activity in plasma.
The DNA methylation level of WIF1 promoter was lower in the cfDNA of NSCLC patients with a complete or partial response to gefitinib, and NSCLC patients with hypomethylated WIF1 showed better PFS and OS. The DNA methylation of WIF1 promoter in the resected tumor tissues was consistent with WIF1 DNA methylation in cfDNA, indicating that cfDNA was mainly derived from lung cancer tissues. As a result, the expression of WIF1 in tissue samples and the WIF1 activity in plasma was inhibited in patients with hypermethylated WIF1. Moreover, the cell viability of gefitinib-resistant cells was decreased by the suppressed WIF1 methylation in vitro. And the expression level of WIF1 mRNA was higher in gefitinib-resistant cells overexpressing ALKBH5, a known suppressor of WIF1 methylation.
In summary, the findings of this study demonstrated that the level of WIF1 methylation in cfDNA was associated with the insusceptibility of gefitinib in the treatment of lung cancer.
靶向癌症疗法为肿瘤治疗带来了曙光，尤其是对非小细胞肺癌患者而言。然而，仅有一小部分携带特定突变的 NSCLC 患者对药物治疗反应理想。此外，DNA 甲基化状态在癌症检测和预后预测方面具有巨大潜力。
采用亚硫酸氢盐测序法分析 NSCLC 患者 cfDNA 和肿瘤组织样本中 WIF1 启动子的 DNA 甲基化。通过 PFS 和 OS 分析，评估 WIF1 不同 DNA 甲基化水平对吉非替尼治疗患者的预后影响。采用定量实时 PCR 分析 WIF1 mRNA 的表达，免疫组织化学法评估 WIF1 蛋白的表达，同时采用 ELISA 评估血浆中 WIF1 的活性。
吉非替尼完全或部分缓解的 NSCLC 患者 cfDNA 中 WIF1 启动子的 DNA 甲基化水平较低，且 WIF1 低甲基化的 NSCLC 患者 PFS 和 OS 更好。切除肿瘤组织中 WIF1 启动子的 DNA 甲基化与 cfDNA 中的 WIF1 DNA 甲基化一致，表明 cfDNA 主要来源于肺癌组织。因此，WIF1 在组织样本中的表达和血浆中的 WIF1 活性在 WIF1 高甲基化患者中受到抑制。此外，在体外通过抑制 WIF1 甲基化降低了对吉非替尼耐药的细胞的活力。并且，在过表达已知的 WIF1 甲基化抑制剂 ALKBH5 的吉非替尼耐药细胞中，WIF1 mRNA 的表达水平更高。
综上所述，本研究发现 cfDNA 中 WIF1 甲基化水平与肺癌中吉非替尼的耐药性有关。
