Unraveling tumor-microenvironmental communication in nascent bone metastasis utilizing zebrafish xenografts

骨转移是转移性癌症相关死亡和共病的重要原因。尽管骨转移很重要，但其潜在的机制仍然知之甚少。肿瘤微环境(TME)与癌细胞的沟通可提高细胞存活率、治疗耐受性和转移能力。由于骨组织的可获得性差，骨转移的体内研究受到限制。因此，我们建议利用斑马鱼来模拟人类乳腺和前列腺癌细胞对造血组织的转移定植。透明的斑马鱼幼体通过在整个动物水平上的高分辨率实时成像，以及对这一过程的遗传调控，可以有效地可视化早期转移的整个过程。为了研究TME的通讯，我们开发了一个斑马鱼模型，在该模型中，TME细胞与植入的人类癌细胞相互作用时会改变颜色，从而可以定义循环和播散的肿瘤细胞与造血龛(相当于骨龛)的相互作用。总体目标是利用这个系统来确定不同的成骨细胞TME植入后的共同遗传特征。此外，我们将比较单个的成骨细胞和它们的母系，以确定其表达与增强的造血生态位植入相关的基因。生物信息学分析将被用来确定最有希望的候选基因以及可能控制TME-癌症轴的信号通路。候选基因和途径将通过半高通量F0清晰度或药物抑制物筛选来验证。最有希望的靶点将在体外和体内哺乳动物系统中得到验证。最后，将评估候选基因在人类乳腺癌和骨转移组织中的表达。总之，我们的分析将确定乳腺癌和前列腺癌细胞定植到骨骼的新机制，以及用于骨转移早期诊断和精确医学的特定靶点的潜在标记物。

Bone metastasis contributes strongly to metastatic cancer-related death and co-morbidity. Despite its importance, mechanisms underlying bone metastasis remain poorly understood. Communication of the tumor microenvironment (TME) with the cancer cells leads to enhanced cell survival, treatment resistance, and metastasis. The in vivo study of bone metastasis is limited due to the poor accessibility of bone tissue. Therefore, we propose to utilize the zebrafish to model metastatic colonization of hematopoietic tissue by human breast and prostate cancer cells. The transparent zebrafish larva allows efficient visualization of the entire process of early metastasis by live high-resolution imaging, on a whole animal level, as well as genetic modulation of the process. To study the TME communication, we have developed a zebrafish model in which TME cells change color upon interaction with engrafted human cancer cells allowing to define interactions of circulating and disseminated tumor cells with the hematopoietic niche, the equivalent of the bone niche. Overall aim is to utilize this system to determine the shared genetic signature of the TME post-engraftment of different osteotropic cells. Additionally, we will compare the individual osteotropic cells with their maternal line to identify genes whose expression is correlated with enhanced hematopoietic niche engraftment. A bioinformatic analysis will be used to identify the most promising candidate genes as well as signaling pathways potentially controlling the TME-cancer-axis. Candidate genes and pathways will be validated by a semi-high throughput F0 crispant or pharmacological inhibitor screen. The most promising targets will be validated in vitro and in vivo mammalian systems. Finally, candidate gene expression will be assessed in human breast cancer and bone metastasis tissue. Collectively, our analysis will identify novel mechanisms of breast and prostate cancer cell colonization into the bone as well as potential markers for early diagnosis and specific targeting of bone metastases towards precision medicine.