Optical Bioimaging Laboratory, Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, 117576, Singapore.
National Neuroscience Institute, 308433, Singapore.
Anal Chem. 2021 Feb 2;93(4):2377-2384. doi: 10.1021/acs.analchem.0c04262. Epub 2021 Jan 14.
Recent genomic studies on the glioblastoma (GBM) subtypes (, mesenchymal, proneural, and classical) pave a way for effective clinical treatments of the recurrent brain tumor. However, identification of the GBM subtype is complicated by the intratumoral heterogeneity that results in coexistence of multiple subtypes within the tissue specimen. Here, we present the use of hyperspectral stimulated Raman scattering (SRS) microscopy for rapid, label-free molecular assessment of GBM intratumoral heterogeneity with submicron resolution. We develop a unique label-free Raman imaging diagnostic platform consisting of the spectral focusing hyperspectral SRS imaging of the large-area GBM tissue specimens, SRS images, and spectrum retrieval using the multivariate curve resolution algorithm and subtype classification based on the quadratic support vector machine model for rapid molecular subtyping of GBMs. Both the stain-free SRS histological images and 2D subtype maps can be obtained within 20-30 min which is superior to the days of the conventional single-cell RNA sequencing. While the SRS histology assesses the demyelination status as a new diagnostic feature, the SRS mapping provides a new insight into intratumoral heterogeneity across GBM tissue specimens. We find that the major proportions of the GBM tissues agree with the diagnostic results of the genomic analysis, but nontrivial portions of the remaining SRS image tiles in the specimens are found to belong to other molecular subtypes, implying the substantial degree of GBM heterogeneity. The rapid SRS imaging diagnostic platform developed has shown the ability of unveiling tumor heterogeneity in GBM tissues accurately, which would promote the improvement of the GBM-targeted therapy in near future.
最近对胶质母细胞瘤（GBM）亚型（间充质型、神经型、经典型）的基因组研究为复发性脑肿瘤的有效临床治疗铺平了道路。然而，由于肿瘤内异质性导致组织标本中存在多种亚型共存，因此确定 GBM 亚型变得复杂。在这里，我们展示了使用高光谱受激拉曼散射（SRS）显微镜对 GBM 肿瘤内异质性进行快速、无标记的分子评估，具有亚微米分辨率。我们开发了一种独特的无标记拉曼成像诊断平台，包括对大面积 GBM 组织标本的光谱聚焦高光谱 SRS 成像、SRS 图像以及使用多元曲线分辨算法进行的光谱检索，以及基于二次支持向量机模型的亚型分类，用于快速对 GBM 进行分子分型。无染色的 SRS 组织学图像和 2D 亚型图都可以在 20-30 分钟内获得，这比传统的单细胞 RNA 测序快几天。虽然 SRS 组织学评估脱髓鞘状态作为一种新的诊断特征，但 SRS 映射提供了对 GBM 组织标本内肿瘤内异质性的新见解。我们发现，GBM 组织的主要比例与基因组分析的诊断结果一致，但在标本中仍有相当一部分 SRS 图像块属于其他分子亚型，这意味着 GBM 异质性程度相当大。所开发的快速 SRS 成像诊断平台已显示出准确揭示 GBM 组织中肿瘤异质性的能力，这将促进未来 GBM 靶向治疗的改善。
