PO.ET03.08 · 实验与分子治疗
配体将EGFR的重新激活与NSCLC中对KRAS G12C抑制剂的耐药联系起来
Ligand links EGFR reactivation to resistance against KRAS G12C inhibitors in NSCLC
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
KRAS G12C抑制剂对KRAS G12C突变型非小细胞肺癌（NSCLC）显示出有意义的临床疗效，为这一历来难以靶向的癌基因提供了期待已久的治疗选择。然而，固有和获得性耐药都常常限制应答的持久性。为克服这些局限，迫切需要基于分子机制的合理联合策略。尽管多种联合方法——如共同靶向EGFR或PD-L1——正在进行中的试验中被评估，但生物标志物驱动的治疗选择仍不成熟。为阐明耐药的潜在机制，我们使用小鼠和患者来源异种移植（PDX）建立了固有和获得性KRAS G12C抑制剂耐药肿瘤模型。进行了包括Western印迹和酶联免疫吸附测定（ELISA）在内的机制分析，以表征耐药相关信号。在体外和体内验证了联合治疗的疗效。此外，对异种移植组织以及接受sotorasib治疗的KRAS G12C突变型NSCLC患者的肿瘤样本进行了免疫组织化学（IHC）和RNAscope原位杂交（ISH）。我们的发现揭示，肿瘤细胞自分泌配体介导的表皮生长因子受体（EGFR）磷酸化在对KRAS抑制剂的固有和获得性耐药中均起核心作用。引人注目的是，同样的EGFR信号轴也在软脑膜癌病模型的中枢神经系统（CNS）转移复发中被检测到，表明其与庇护部位疾病进展的相关性。此外，RNAscope ISH能够对配体表达进行空间可视化，提示其作为识别EGFR依赖性耐药患者的诊断标志物的潜力。重要的是，联合抑制KRAS和EGFR在体外和体内有效抑制了肿瘤生长并克服了耐药。与这些临床前结果一致，在七个来自对sotorasib应答不佳的KRAS G12C突变型NSCLC患者的临床肿瘤样本中，有两个观察到EGFR配体mRNA表达升高。总之，配体介导的EGFR激活是NSCLC中对KRAS G12C抑制剂固有和获得性耐药的关键驱动因素。这些结果为使用KRAS和EGFR同步抑制的生物标志物指导联合治疗建立了机制依据，以增强治疗疗效并预防KRAS G12C突变型肺癌中的耐药。
查看英文原文 English abstract
KRAS G12C inhibitors have shown meaningful clinical efficacy against Kirsten rat sarcoma viral oncogene (KRAS) G12C-mutant non-small cell lung cancer (NSCLC), providing a long-awaited therapeutic option for this historically difficult-to-target oncogene. However, both intrinsic and acquired resistance frequently limit the durability of response. To overcome these limitations, rational combination strategies based on molecular mechanisms are urgently needed. Although multiple combination approaches-such as co-targeting EGFR or PD-L1-are being evaluated in ongoing trials, biomarker-driven therapeutic selection remains underdeveloped. To elucidate the mechanisms underlying resistance, we established intrinsic and acquired KRAS G12C inhibitor-resistant tumor models using mouse and patient-derived xenografts (PDX). Mechanistic analyses, including western blotting and enzyme-linked immunosorbent assay (ELISA), were conducted to characterize resistance-associated signaling. Combination treatment efficacy was validated in vitro and in vivo. In addition, immunohistochemistry (IHC) and RNAscope in situ hybridization (ISH) were performed on xenograft tissues and tumor samples from patients with KRAS G12C-mutant NSCLC treated with sotorasib. Our findings reveal that tumor cell-autocrine ligand-mediated epidermal growth factor receptor (EGFR) phosphorylation plays a central role in both intrinsic and acquired resistance to KRAS inhibitors. Strikingly, this same EGFR signaling axis was also detected in central nervous system (CNS) metastatic recurrence in a leptomeningeal carcinomatosis model, indicating its relevance to disease progression in sanctuary sites. Moreover, RNAscope ISH enabled spatial visualization of ligand expression, suggesting its potential as a diagnostic marker for identifying patients with EGFR-dependent resistance. Importantly, combined inhibition of KRAS and EGFR effectively suppressed tumor growth and overcame resistance in vitro and in vivo. Consistent with these preclinical results, elevated EGFR ligand mRNA expression was observed in two of seven clinical tumor samples from patients with KRAS G12C-mutant NSCLC who exhibited poor response to sotorasib. In conclusion, ligand-mediated EGFR activation serves as a key driver of both intrinsic and acquired resistance to KRAS G12C inhibitors in NSCLC. These results establish a mechanistic rationale for biomarker-guided combination therapy using concurrent KRAS and EGFR inhibition to enhance therapeutic efficacy and prevent resistance in KRAS G12C-mutant lung cancer.
利益披露 Disclosure
S. Nanjo, None..
Y. Liu, None..
H. Koba, None..
S. Yano, None.