Morgaenko Katerina, Arneja Abhinav, Ball Alexander G, Putelo Audrey M, Munson Jennifer M, Rutkowski Melanie R, Pompano Rebecca R
Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, United States.
Carter Immunology Center and University of Virginia Cancer Center, University of Virginia School of Medicine, Charlottesville, VA, United States.
bioRxiv. 2024 Jul 22:2024.07.18.601753. doi: 10.1101/2024.07.18.601753.
Lymph nodes (LNs) are common sites of metastatic invasion in breast cancer, often preceding spread to distant organs and serving as key indicators of clinical disease progression. However, the mechanisms of cancer cell invasion into LNs are not well understood. Existing in vivo models struggle to isolate the specific impacts of the tumor-draining lymph node (TDLN) milieu on cancer cell invasion due to the co-evolving relationship between TDLNs and the upstream tumor. To address these limitations, we used live ex vivo LN tissue slices with intact chemotactic function to model cancer cell spread within a spatially organized microenvironment. After showing that BRPKp110 breast cancer cells were chemoattracted to factors secreted by naïve LN tissue in a 3D migration assay, we demonstrated that ex vivo LN slices could support cancer cell seeding, invasion, and spread. This novel approach revealed dynamic, preferential cancer cell invasion within specific anatomical regions of LNs, particularly the subcapsular sinus (SCS) and cortex, as well as chemokine-rich domains of immobilized CXCL13 and CCL1. While CXCR5 was necessary for a portion of BRPKp110 invasion into naïve LNs, disruption of CXCR5/CXCL13 signaling alone was insufficient to prevent invasion towards CXCL13-rich domains. Finally, we extended this system to pre-metastatic TDLNs, where the ex vivo model predicted a lower invasion of cancer cells. The reduced invasion was not due to diminished chemokine secretion, but it correlated with elevated intranodal IL-21. In summary, this innovative ex vivo model of cancer cell spread in live LN slices provides a platform to investigate cancer invasion within the intricate tissue microenvironment, supporting time-course analysis and parallel read-outs. We anticipate that this system will enable further research into cancer-immune interactions and allow isolation of specific factors that make TDLNs resistant to cancer cell invasion, which are challenging to dissect in vivo.
淋巴结（LNs）是乳腺癌转移侵袭的常见部位，通常先于癌细胞扩散至远处器官，并作为临床疾病进展的关键指标。然而，癌细胞侵袭淋巴结的机制尚未完全明确。由于肿瘤引流淋巴结（TDLN）与上游肿瘤之间存在共同进化的关系，现有的体内模型难以分离TDLN微环境对癌细胞侵袭的特定影响。为了解决这些局限性，我们使用具有完整趋化功能的离体活淋巴结组织切片，在空间组织化的微环境中模拟癌细胞扩散。在三维迁移试验中证明BRPKp110乳腺癌细胞被未接触肿瘤的淋巴结组织分泌的因子趋化后，我们证实离体淋巴结切片能够支持癌细胞播种、侵袭和扩散。这种新方法揭示了癌细胞在淋巴结特定解剖区域内的动态、优先侵袭，特别是被膜下窦（SCS）和皮质，以及固定化CXCL13和CCL1富含趋化因子的区域。虽然CXCR5对于BRPKp110侵入未接触肿瘤的淋巴结的一部分过程是必需的，但单独破坏CXCR5/CXCL13信号不足以阻止癌细胞向富含CXCL13的区域侵袭。最后，我们将该系统扩展到转移前的TDLN，离体模型预测癌细胞的侵袭较少。侵袭减少并非由于趋化因子分泌减少，而是与淋巴结内IL-21升高有关。总之，这种在活淋巴结切片中癌细胞扩散的创新离体模型提供了一个平台，用于研究复杂组织微环境中的癌症侵袭，支持时间进程分析和平行读数。我们预计该系统将有助于进一步研究癌症与免疫的相互作用，并能够分离出使TDLN对癌细胞侵袭具有抗性的特定因素，而这些因素在体内难以剖析。
