Fu Guowei, Li Jin, Zhang Qian, Lv Changjun, Zhang Zhiyang, Wang Xiaoyan, Wu Rihui, Chen Lingxin
Guangdong Provincial Key Laboratory of Large Animal Models for Biomedicine, School of Pharmacy and Food Engineering, Wuyi University 529020 Jiangmen China
CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences 264003 Yantai China
Chem Sci. 2025 May 9. doi: 10.1039/d5sc01912e.
Microsatellite instability (MSI) is a hallmark of colorectal cancer in immunotherapy, whose phenotypes mainly involve four mismatch repair (MMR) proteins (MlH1, MSH2, MSH6 and PMS2). Since these MMR proteins are highly interdependent, simultaneous detection of these proteins rather than separate detection in cancer is vital to accurately distinguish the MSI phenotypes. In this study, we fabricated four orthogonal gap-enhanced Raman tag (O-GERT) flavors with high sensitivity, superb photostability, and completely separated interference-free signal readouts. With antibody functionalization, these multicolored O-GERTs allowed one-shot detection of these four MMR proteins in cancer tissues with high specificity and spectral resolution. Based on quantitative Raman imaging, these cancer tissues were classified into microsatellite stable (MSS) or high-frequency MSI (MSI-H) subtypes. The detected MSI-H ratios for colorectal, breast and gastric cancers were 13.3%, 6.7% and 3.3%, respectively. Moreover, the correlation between the expression levels of these MMR proteins in colorectal cancer and related clinicopathologic parameters in these subtypes was established for the first time. We further demonstrated that MSI in cancer can serve as a tool for screening Lynch syndrome (a genetic disorder) and predicting potential candidates for immunotherapy by PD1/PD-L1 blockade. To the best of our knowledge, this is the first example of quantitative multiplexed Raman imaging for fast detection of MSI in cancer.
微卫星不稳定性（MSI）是免疫治疗中结直肠癌的一个标志，其表型主要涉及四种错配修复（MMR）蛋白（MlH1、MSH2、MSH6和PMS2）。由于这些MMR蛋白高度相互依赖，因此在癌症中同时检测这些蛋白而非单独检测对于准确区分MSI表型至关重要。在本研究中，我们制备了四种具有高灵敏度、卓越光稳定性和完全分离的无干扰信号读出的正交间隙增强拉曼标签（O-GERT）变体。通过抗体功能化，这些多色O-GERT能够以高特异性和光谱分辨率一次性检测癌症组织中的这四种MMR蛋白。基于定量拉曼成像，这些癌症组织被分类为微卫星稳定（MSS）或高频MSI（MSI-H）亚型。结直肠癌、乳腺癌和胃癌的检测到的MSI-H比率分别为13.3%、6.7%和3.3%。此外，首次建立了这些MMR蛋白在结直肠癌中的表达水平与这些亚型中相关临床病理参数之间的相关性。我们进一步证明，癌症中的MSI可作为筛查林奇综合征（一种遗传性疾病）和预测通过PD1/PD-L1阻断进行免疫治疗的潜在候选者的工具。据我们所知，这是用于快速检测癌症中MSI的定量多重拉曼成像的首个实例。
