Metabolic Photonics Laboratory, Departments of Surgery and Biomedical Sciences, Cedars-Sinai Medical Center, 8700 Beverly Blvd. Davis 6067, Los Angeles, CA, 90048, USA.
Department of Biomedical Sciences, Cedars-Sinai Medical Center, 8700 Beverly Blvd., Los Angeles, CA, 90048, USA.
Mol Imaging Biol. 2019 Jun;21(3):436-446. doi: 10.1007/s11307-019-01324-7.
In order to monitor the drug responses of three-dimensional mammary tumor spheroids and to elucidate the role of inter- and intra-spheroid heterogeneity in determining drug sensitivity in the spheroids, an integrated image analysis framework was developed for morphometric and metabolic characterization of the three-dimensional tumor spheroids.
Three-dimensional spheroid cultures of primary mammary tumor epithelial cells isolated from freshly excised tumors from a transgenic mouse model of adenocarcinoma (MMTV-PyMT) were imaged by using vital dyes and mitochondrial membrane potential markers. Custom-developed java and python program codes facilitated image processing, numerical computation, and graphical analysis of large datasets generated from the experiments. A panel of cancer drugs (rapamycin, BEZ235, MK2206, and flavopiridol) was tested to determine the degree of drug sensitivity as well as heterogeneity in drug response.
A new quantitative metric (growth/toxicity) was developed based on morphometric parameters that were found to track the growth and apoptotic cell populations. Further, this study identified two parameters, namely, skew and kurtosis-which report the spatial heterogeneity in mitochondrial metabolism within the spheroids. The results of this study show that three-dimensional tumor spheroids selectively respond to cancer drugs depending on the specific metabolic pathways (AKT inhibition pathway in the present study), and there exists significant heterogeneity in the untreated tumor spheroids. Drug sensitivity of the spheroids was found to be associated with significant alterations in mitochondrial heterogeneity within the spheroids.
In conclusion, the quantitative imaging of morphometric and metabolic analysis in large image datasets can serve as an excellent tool box for characterizing tumor heterogeneity in three-dimensional tumor spheroids and potentially, in intact tumors as well.
为了监测三维乳腺肿瘤球体的药物反应，并阐明球体中细胞间和细胞内异质性在确定球体中药物敏感性方面的作用，开发了一种综合的图像分析框架，用于对三维肿瘤球体进行形态计量学和代谢特征分析。
使用活染料和线粒体膜电位标记物对从转基因小鼠模型腺癌（MMTV-PyMT）中切除的新鲜肿瘤中分离的原代乳腺肿瘤上皮细胞的三维球体培养物进行成像。定制的 Java 和 Python 程序代码便于处理从实验中生成的大型数据集的图像处理、数值计算和图形分析。测试了一组癌症药物（雷帕霉素、BEZ235、MK2206 和 flavopiridol），以确定药物敏感性以及药物反应的异质性程度。
基于形态计量学参数开发了一种新的定量指标（生长/毒性），该指标被发现可以跟踪生长和凋亡细胞群体。此外，本研究确定了两个参数，即偏度和峰度，它们报告了球体中线粒体代谢的空间异质性。本研究的结果表明，三维肿瘤球体根据特定的代谢途径（本研究中的 AKT 抑制途径）选择性地对癌症药物产生反应，并且未处理的肿瘤球体中存在显著的异质性。发现球体的药物敏感性与球体中线粒体异质性的显著改变有关。
总之，对形态计量学和代谢分析的大量图像数据集进行定量成像，可以作为一种极好的工具盒，用于对三维肿瘤球体中的肿瘤异质性进行特征描述，并且在完整肿瘤中也具有潜力。
