Guan Shaoxing, Chen Xi, Chen Youhao, Xie Wen, Liang Heng, Zhu Xia, Yang Yunpeng, Fang Wenfeng, Huang Yan, Zhao Hongyun, Zhuang Wei, Liu Shu, Huang Min, Wang Xueding, Zhang Li
Laboratory of Drug Metabolism and Pharmacokinetics, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou City, Guangzhou, P. R. China.
State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, P. R. China.
Clin Cancer Res. 2022 Sep 1;28(17):3770-3784. doi: 10.1158/1078-0432.CCR-22-0791.
Although gefitinib prolonged the progression-free survival (PFS) of patients with non-small cell lung cancer (NSCLC), unpredictable resistance limited its clinical efficacy. Novel predictive biomarkers with explicit mechanisms are urgently needed.
A total of 282 patients with NSCLC with gefitinib treatment were randomly assigned in a 7:3 ratio to exploratory (n = 192) and validation (n = 90) cohorts. The candidate polymorphisms were selected with Haploview4.2 in Hapmap and genotyped by a MassARRAY system, and the feature variables were identified through Randomforest Survival analysis. Tanswell and clonogenic assays, base editing and cell-derived tumor xenograft model were performed to uncover the underlying mechanism.
We found that the germline missense polymorphism rs3742076 (A>G, S628P), located in transactivation domain of FOXM1, was associated with PFS in exploratory (median PFS: GG vs. GA&AA, 9.20 vs. 13.37 months, P = 0.00039, HR = 2.399) and validation (median PFS: GG vs. GA&AA, 8.13 vs. 13.80 months, P = 0.048, HR = 2.628) cohorts. We elucidated that rs3742076_G conferred resistance to gefitinib by increasing protein stability of FOXM1 and facilitating an aggressive phenotype in vitro and in vivo through activating wnt/β-catenin signaling pathway. Meanwhile, FOXM1 level was highly associated with prognosis in patients with EGFR-mutant NSCLC. Mechanistically, FOXM1 rs3742076_G upregulated wnt/β-catenin activity by directly binding to β-catenin in cytoplasm and promoting transcription of β-catenin in nucleus. Remarkably, inhibition of β-catenin markedly reversed rs3742076_G-induced gefitinib resistance and aggressive phenotypes.
These findings characterized rs3742076_G as a gain-of-function polymorphism in mediating gefitinib resistance and tumor aggressiveness, and highlighted the variant as a predictive biomarker in guiding gefitinib treatment.
尽管吉非替尼可延长非小细胞肺癌（NSCLC）患者的无进展生存期（PFS），但其不可预测的耐药性限制了其临床疗效。迫切需要具有明确机制的新型预测生物标志物。
将282例接受吉非替尼治疗的NSCLC患者按7:3的比例随机分为探索性队列（n = 192）和验证性队列（n = 90）。在Hapmap中使用Haploview4.2选择候选多态性，并通过MassARRAY系统进行基因分型，通过随机森林生存分析确定特征变量。进行Transwell和克隆形成试验、碱基编辑和细胞衍生的肿瘤异种移植模型以揭示潜在机制。
我们发现位于FOXM1反式激活结构域的种系错义多态性rs3742076（A>G，S628P）与探索性队列（中位PFS：GG与GA&AA，9.20 vs. 13.37个月，P = 0.00039，HR = 2.399）和验证性队列（中位PFS：GG与GA&AA，8.13 vs. 13.80个月，P = 0.048，HR = 2.628）中的PFS相关。我们阐明，rs3742076_G通过增加FOXM1的蛋白质稳定性并通过激活wnt/β-连环蛋白信号通路在体外和体内促进侵袭性表型，从而赋予对吉非替尼的耐药性。同时，FOXM1水平与EGFR突变的NSCLC患者的预后高度相关。机制上，FOXM1 rs3742076_G通过直接与细胞质中的β-连环蛋白结合并促进细胞核中β-连环蛋白的转录来上调wnt/β-连环蛋白活性。值得注意的是，抑制β-连环蛋白可明显逆转rs3742076_G诱导的吉非替尼耐药性和侵袭性表型。
这些发现将rs3742076_G表征为介导吉非替尼耐药性和肿瘤侵袭性的功能获得性多态性，并强调该变体作为指导吉非替尼治疗的预测生物标志物。
