Morphological analysis of the mechanisms of organ-specific metastasis using intravital multiphoton microscopy

我们利用活体TPLSM可视化了肿瘤微环境中癌细胞与基质细胞之间的相互作用，以及转移性肿瘤移植的体内实时化疗反应。脾内注射癌细胞后，癌细胞被抑制在肝窦内。在癌细胞周围观察到血小板聚集，提示肿瘤细胞诱导血小板聚集（TCIPA）现象。癌细胞从肝窦外渗至间隙。在癌细胞周围观察到库普弗细胞的突起，表明库普弗细胞似乎吞噬癌细胞。5-氟尿嘧啶（5-FU）或伊立替康化疗后，观察到肿瘤细胞碎裂、凝结、肿胀及细胞内空泡。我们还观察到结直肠癌肝转移瘤血管内血小板聚集和血流相对减少。癌细胞脾内注射前给药5-FU不影响癌细胞对肝窦内皮细胞的粘附。由于皮下肿瘤的生长速度比肝转移瘤快，所以我们没有建立荷瘤小鼠肝转移模型。

We visualized the interactions between cancer cells and stromal cells in tumor microenvironment with regard to ‘organ-specific metastasis, and in vivo real-time chemotherapy response for metastatic tumor xenografts using intravital TPLSM. Cancer cells were arrested within hepatic sinusoids after intrasplenic cancer cell injection. Platelet aggregation surrounding a cancer cell was observed, indicating a phenomenon of tumor-cell induced platelet aggregation (TCIPA). Cancer cells were extravasated from hepatic sinusoids to the space of Disse. Protrusions of Kupffer cells surrounding a cancer cell were observed, indicating that Kupffer cells appear to phagocytose cancer cells. After 5-fluorouracil (5-FU) or irinotecan chemotherapy, tumor cell fragmentation, condensation, swelling and intracellular vacuoles were observed. The platelet aggregation and the relatively decreased blood flow in the tumor vessels of colorectal liver metastases were also observed. 5-FU administration prior to the intrasplenic injection of cancer cells didn’t influence the adhesion of cancer cells to endothelial cells of hepatic sinusoids. We didn’t establish a liver metastasis model in subcutaneous tumor bearing mice because of the faster growth of subcutaneous tumor than liver metastatic tumor.