利用同步辐射红外光谱技术探索结直肠癌对EGFR单抗治疗的疗效预测及耐药机制的研究

The mechanism of cetuximab resistance in RAS wild-type colorectal cancer patients is still unclear, and there is no reliable biomarker to accurately predict the sensitivity of cetuximab treatment in clinical practice. In the preliminary study, by adopting synchrotron radiation based Fourier-transform infrared (SR-FTIR) technique, we found a saturated fatty acid absorption peak in cetuximab-sensitive organoid compared with cetuximab-resistant organoid and found that the increase of acetyl CoA produced by beta-oxidation of fatty acids in cetuximab-resistant organoid may contribute to drug resistance. Based on above evidence, we hypothesize that resistance to cetuximab is related to the increase of fatty acid metabolism, and that the increase of acetyl CoA produced by intracellular beta-oxidation is the direct cause of cetuximab resistance. Further studies will be carried out towards organoid, animal model and clinical sample levels: ①Expand the sample size of SR-FTIR analysis to verify that the saturated fatty acid absorption peak is related to cetuximab resistance and verify its subcellular localization; ②Use organoid and animal models to demonstrate that enhanced fatty acid beta-oxidation can promote cetuximab resistance, and that combined use of cetuximab and beta-oxidation inhibitors can rescue cetuximab resistance. ③Prospectively collect clinical samples for further validation. Our study aims to provide a new target for reversing cetuximab resistance.

RAS野生型肠癌患者对西妥昔单抗耐药的机制尚不明确，临床上缺乏能够精准预测西妥昔单抗治疗敏感性的可靠指标。我们在前期研究中利用同步辐射红外光谱技术（SR-FTIR）发现西妥昔单抗敏感类器官较耐药类器官出现一个饱和脂肪酸吸收峰，初步机制研究提示耐药类器官中脂肪酸的β-氧化产生乙酰CoA增加，提示脂肪酸分解利用增加可能是西妥昔单抗耐药的原因。据此，我们提出科学假设，西妥昔单抗耐药与脂肪酸代谢增加有关，细胞内通过β-氧化产生的乙酰CoA含量增高是诱导西妥昔单抗耐药的直接原因。我们将在类器官、动物模型、临床样本水平进行进一步研究：①扩大样本量行SR-FTIR技术分析，验证饱和脂肪酸吸收峰的消失与西妥昔单抗耐药相关，并进行亚细胞定位；②在类器官及动物模型中验证脂肪酸β-氧化增强可促进西妥昔单抗耐药，联合应用β-氧化抑制剂可逆转耐药；③前瞻性收集临床样本进行进一步验证，拟为逆转西妥昔单抗耐药提供新靶点

RAS野生型左半右半肠癌患者对针对EGFR的单抗，例如西妥昔单抗，的敏感性不同，其耐药机制尚不明确，缺乏药敏预测模型；晚期肠癌患者多发肝转移，原发灶与转移灶的差异揭示尚不完全，能够保留肿瘤组织大部分特征的类器官对于肠癌肝转移患者的药敏及预后预测价值未经充分评估；对于不可切除的肠癌肝转移患者目前尚缺乏理想的药敏预测模型。在本项目研究中，我们构建了RAS野生型左半右半结肠癌患者的类器官库，优化了西妥昔药敏检测系统，并通过蛋白组学构建了西妥昔药敏预测模型的雏形，揭示了西妥昔敏感型与抵抗型肠癌组织的差异通路和差异蛋白；构建了肠癌配对肝转移类器官库，通过形态学，病理学，基因组学，转录组学，单细胞RNA测序等多种手段，揭示了不同肿瘤患者之间的异质性，同一肿瘤患者原发灶与转移灶之间的一致性与异质性，明确了原发灶与转移灶类器官药物敏感的一致性，并发现类器官能够预测患者的临床药敏及预后；开发了适用于不可切除的肠癌肝转移患者药物筛选的循环肿瘤细胞类器官培养方法。我们的研究成果为RAS野生型肠癌患者及肝转移患者的药物选择，疗效提高提供了科研基础。