A zebrafish model of OSCC microenvironment to study neoplastic cell dissemination and the influence of pharmacological therapeutic interventions

Abstract

The zebrafish model has several advantages and also unique characteristics that are attractive to the study of tumor-stroma system interactions, such as: high fecundity, short generation time, large number of offspring that reduces turnaround time for the experiments, external embryonic development that allows for the use of immunologically-immature larvae forms, small size that makes it amenable to therapeutic drug trials with low cost, optical clarity that allows in vivo visualization of fluorescent-tagged cells and monitoring processes including angiogenesis, tumor growth, and cell-cell interaction. These aspects of zebrafish biology are valuable for an in vivo model of cancer both from practical and scientific perspectives. Macrophages and neutrophils develop in the first two days of zebrafish embryogenesis, and there is no adaptive immune system in the first 30 days of development. This temporal segregation of immune development allows for the study of tumor-innate immunity interactions in the absence of adaptive immunity and makes it amenable to xenografts. The intention is to take advantage of the zebrafish model in tracking the dissemination of tumor cells according to the experimental conditions. We plan to mimic the tumor microenvironment in this model and assess tumor cell dissemination as the primary outcome. Human cancer associated fibroblasts (CAFs), monocytes and oral squamous cell carcinoma (OSCC) cells will be injected in zebrafish larvae as xenografts and the influence of the test compounds/conditions (paclitaxel, pirfenidone and ATN-161) both independently and combined with radiotherapy currently used in OSCC. The hypothesis for this experiment is the same for the research proposal submitted: interactions of neoplastic cells with macrophages, fibroblasts and fibronectin (via alpha5beta1 integrin) influence tumor cell dissemination. This experiment will expand the findings of in vitro and in vivo experiments included in the ongoing funded project, complementing the information with a powerful in vivo model in which pharmacological interventions will be administered systemically, similarly to the clinical management of OSCC. (AU)