Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, UK.
Department of Physiology & Medical Physics and Centre for Systems Medicine, Royal College of Surgeons in Ireland (RCSI) University of Medicine and Health Sciences, Dublin, Ireland.
FEBS J. 2021 Sep;288(18):5374-5388. doi: 10.1111/febs.15801. Epub 2021 Mar 27.
Resistance to chemotherapy-induced cell death is a major barrier to effective treatment of solid tumours such as colorectal cancer, CRC. Herein, we present a study aimed at developing a proteomics-based predictor of response to standard-of-care (SoC) chemotherapy in combination with antagonists of IAPs (inhibitors of apoptosis proteins), which have been implicated as mediators of drug resistance in CRC. We quantified the absolute expression of 19 key apoptotic proteins at baseline in a panel of 12 CRC cell lines representative of the genetic diversity seen in this disease to identify which proteins promote resistance or sensitivity to a model IAP antagonist [birinapant (Bir)] alone and in combination with SoC chemotherapy (5FU plus oxaliplatin). Quantitative western blotting demonstrated heterogeneous expression of IAP interactome proteins across the CRC cell line panel, and cell death analyses revealed a widely varied response to Bir/chemotherapy combinations. Baseline protein expression of cIAP1, caspase-8 and RIPK1 expression robustly correlated with response to Bir/chemotherapy combinations. Classifying cell lines into 'responsive', 'intermediate' and 'resistant' groups and using linear discriminant analysis (LDA) enabled the identification of a 12-protein signature that separated responders to Bir/chemotherapy combinations in the CRC cell line panel with 100% accuracy. Moreover, the LDA model was able to predict response accurately when cells were cocultured with Tumour necrosis factor-alpha to mimic a pro-inflammatory tumour microenvironment. Thus, our study provides the starting point for a proteomics-based companion diagnostic that predicts response to IAP antagonist/SoC chemotherapy combinations in CRC.
化疗诱导的细胞死亡耐药是有效治疗结直肠癌（CRC）等实体瘤的主要障碍。在此，我们介绍了一项旨在开发基于蛋白质组学的预测因子的研究，该预测因子可预测标准治疗（SoC）化疗联合凋亡蛋白（IAPs）拮抗剂的反应，IAPs 已被认为是 CRC 耐药的介质。我们在一个代表该疾病遗传多样性的 12 个 CRC 细胞系的面板中，定量测定了 19 种关键凋亡蛋白在基线时的绝对表达水平，以确定哪些蛋白促进对模型 IAP 拮抗剂[birinapant（Bir）]单独和与 SoC 化疗（5FU 加奥沙利铂）的耐药性或敏感性。定量 Western blot 显示，IAP 相互作用蛋白在 CRC 细胞系面板中的表达存在异质性，细胞死亡分析显示，对 Bir/化疗组合的反应差异很大。cIAP1、caspase-8 和 RIPK1 的基线蛋白表达与 Bir/化疗组合的反应密切相关。将细胞系分类为“敏感”、“中间”和“耐药”组，并使用线性判别分析（LDA），可以识别出一个 12 种蛋白质特征，该特征可以 100%准确地将 CRC 细胞系面板中对 Bir/化疗组合有反应的细胞与无反应的细胞区分开来。此外，当细胞与肿瘤坏死因子-α共培养以模拟促炎肿瘤微环境时，LDA 模型能够准确预测反应。因此，我们的研究为基于蛋白质组学的预测因子提供了起点，该预测因子可预测 CRC 中 IAP 拮抗剂/SoC 化疗组合的反应。
