Olivia Newton-John Cancer Research Institute, Heidelberg, VIC, 3084, Australia.
School of Cancer Medicine, La Trobe University, Bundoora, VIC, 3086, Australia.
Commun Biol. 2023 Aug 7;6(1):821. doi: 10.1038/s42003-023-05167-5.
Intratumoural heterogeneity is associated with poor outcomes in breast cancer. To understand how malignant clones survive and grow in metastatic niches, in vivo models using cell lines and patient-derived xenografts (PDX) have become the gold standard. Injections of cancer cells in orthotopic sites (spontaneous metastasis assays) or into the vasculature (experimental metastasis assays) have been used interchangeably to study the metastatic cascade from early events or post-intravasation, respectively. However, less is known about how these different routes of injection impact heterogeneity. Herein we directly compared the clonality of spontaneous and experimental metastatic assays using the human cell line MDA-MB-231 and a PDX model. Genetic barcoding was used to study the fitness of the subclones in primary and metastatic sites. Using spontaneous assays, we found that intraductal injections resulted in less diverse tumours compared to other routes of injections. Using experimental metastasis assays via tail vein injection of barcoded MDA-MB-231 cells, we also observed an asymmetry in metastatic heterogeneity between lung and liver that was not observed using spontaneous metastasis assays. These results demonstrate that these assays can result in divergent clonal outputs in terms of metastatic heterogeneity and provide a better understanding of the biases inherent to each technique.
肿瘤内异质性与乳腺癌预后不良有关。为了了解恶性克隆如何在转移龛中存活和生长，使用细胞系和患者来源的异种移植（PDX）的体内模型已成为金标准。将癌细胞注射到原位（自发转移测定）或血管内（实验转移测定）已被互换使用，分别研究从早期事件或血管内渗后开始的转移级联。然而，对于这些不同的注射途径如何影响异质性，我们知之甚少。在此，我们使用人源细胞系 MDA-MB-231 和 PDX 模型直接比较了自发和实验性转移测定的克隆性。遗传条形码用于研究原发性和转移性部位亚克隆的适应性。使用自发测定，我们发现与其他注射途径相比，管内注射导致的肿瘤多样性较低。使用通过尾静脉注射条形码 MDA-MB-231 细胞的实验性转移测定，我们还观察到肺和肝之间转移异质性的不对称性，而自发转移测定则没有观察到这种情况。这些结果表明，这些测定方法在转移异质性方面可产生不同的克隆输出，并更好地了解每种技术固有的偏差。
