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合并症的重要原因。尽管其重要性，骨转移的机制仍然知之甚少。肿瘤微环境（TME）与癌细胞的通信导致增强的细胞存活、治疗抗性和转移。由于骨组织的可及性差，骨转移的体内研究受到限制。因此，我们建议利用斑马鱼模型转移定植造血组织的人乳腺癌和前列腺癌细胞。透明的斑马鱼幼虫允许通过活体高分辨率成像在整个动物水平上有效地可视化早期转移的整个过程，以及该过程的遗传调节。为了研究TME通信，我们已经开发了一种斑马鱼模型，其中TME细胞在与移植的人类癌细胞相互作用后改变颜色，允许定义循环和播散的肿瘤细胞与造血小生境（相当于骨小生境）的相互作用。总体目标是利用该系统来确定不同的成骨细胞的移植后TME的共享遗传标记。此外，我们将比较个别的骨细胞与他们的母系，以确定基因的表达与增强造血生态位植入。生物信息学分析将用于识别最有希望的候选基因以及可能控制TME-癌轴的信号通路。候选基因和途径将通过半高通量F0 crispant或药理学抑制剂筛选进行验证。最有前途的目标将在体外和体内哺乳动物系统中进行验证。最后，将评估候选基因在人乳腺癌和骨转移组织中的表达。总的来说，我们的分析将确定乳腺癌和前列腺癌细胞定植到骨骼中的新机制，以及用于早期诊断和针对精准医学的骨转移的特异性靶向的潜在标志物。

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.