目的:结肠癌肝转移患者可以通过手术治愈,但额外肺转移的存在通常会妨碍治愈性治疗.关于驱动肺转移的过程知之甚少。本研究旨在阐明控制肺与肝转移形成的机制。
方法:从具有不同转移模式的结肠肿瘤中建立患者来源的类器官(PDO)培养物。通过将PDO植入盲肠壁来创建概括转移性器官性的小鼠模型。应用光学条形码来追踪肝和肺转移的起源和克隆组成。RNA测序和免疫组织化学用于鉴定转移性器官性的候选决定因素。遗传,药理学,体外和体内建模策略确定了肺转移形成的重要步骤。通过分析患者来源的组织进行验证。
结果:三种不同PDO的盲肠移植产生了具有不同转移性器官性的模型:仅肝脏,仅肺,还有肝肺.通过源自选择克隆的单细胞接种肝转移。通过进入淋巴管系统的肿瘤细胞的多克隆簇接种肺转移,克隆选择非常有限。肺特异性转移与桥粒标志物的高表达有关,包括斑红蛋白.斑红蛋白缺失消除了肿瘤细胞簇形成,淋巴侵入,和肺转移形成。淋巴管生成的药理学抑制减弱了肺转移形成。原发性人类结肠,直肠,食道,与没有肺转移的胃肿瘤相比,有肺转移的胃肿瘤具有更高的N分期和更多的淋巴管内表达血红蛋白的细胞簇。
结论:肺和肝转移形成是根本不同的过程,具有不同的进化瓶颈,播种实体,和解剖学路线。多克隆肺转移源自依赖斑红蛋白的肿瘤细胞簇,进入原发肿瘤部位的淋巴管系统。
Patients with colon cancer with liver metastases may be cured with surgery, but the presence of additional lung metastases often precludes curative treatment. Little is known about the processes driving lung metastasis. This study aimed to elucidate the mechanisms governing lung vs liver metastasis formation.
Patient-derived organoid (PDO) cultures were established from colon tumors with distinct patterns of metastasis. Mouse models recapitulating metastatic organotropism were created by implanting PDOs into the cecum wall. Optical barcoding was applied to trace the origin and clonal composition of liver and lung metastases. RNA sequencing and immunohistochemistry were used to identify candidate determinants of metastatic organotropism. Genetic, pharmacologic, in vitro, and in vivo modeling strategies identified essential steps in lung metastasis formation. Validation was performed by analyzing patient-derived tissues.
Cecum transplantation of 3 distinct PDOs yielded models with distinct metastatic organotropism: liver only, lung only, and liver and lung. Liver metastases were seeded by single cells derived from select clones. Lung metastases were seeded by polyclonal clusters of tumor cells entering the lymphatic vasculature with very limited clonal selection. Lung-specific metastasis was associated with high expression of desmosome markers, including plakoglobin. Plakoglobin deletion abrogated tumor cell cluster formation, lymphatic invasion, and lung metastasis formation. Pharmacologic inhibition of lymphangiogenesis attenuated lung metastasis formation. Primary human colon, rectum, esophagus, and stomach tumors with lung metastases had a higher N-stage and more plakoglobin-expressing intra-lymphatic tumor cell clusters than those without lung metastases.
Lung and liver metastasis formation are fundamentally distinct processes with different evolutionary bottlenecks, seeding entities, and anatomic routing. Polyclonal lung metastases originate from plakoglobin-dependent tumor cell clusters entering the lymphatic vasculature at the primary tumor site.