FishATLAS: Assessment of Organotropism Determination Through Imaging Informatics of Xenografted Zebrafish

Ewing sarcoma patients with metastatic disease have a 5-year survival rate of approximately 28%. The hallmark of this disease is an aberrant transcription factor made by a fusion of Chromosomes 11 and 22 called EWSFLI1. EWSFLI1 expression levels have been correlated with differing responses in cell metastatic propensity, but much remains to be elucidated. Indeed, many current models fail to meet the statistical rigor that is needed for exceedingly spontaneous, rare events like metastasis. To address this need, FishATLAS utilizes zebrafish human cancer cell xenograft images after high fidelity registration using a novel diffeomorphic transformation to display metastatic hot spots of different cancer cell conditions to begin to grasp the deeper underpinnings of organotropism in vivo with individual cancers. Utilizing a suite of statistical tests, FishATLAS determines at a global whole-fish scale and the local microenvironment, if there are statistically different cell hotspots when comparing two or more different conditions. As it stands, data for EWSFLI1, its target SOX6, a non-transformed cell line NIH3T3, TC32 subclones, and melanoma cell lines have all shown unique distributions of metastatic hot spots. These findings serve as a tool for drug discovery and later environmental re-mapping in FishATLAS by allowing transgenic fish images (such as vasculature and lymphatics) to be overlayed onto any historical data set. These can then be used to determine a given microenvironment's contributions to secondary sites of metastasis. In the case of EWSFLI1 and its target SOX6, there was a marked difference upon shRNA-mediated knockdown that removed a population of hotspots in the upper somitic veins while some were persistent post genetic perturbation. SOX6 shRNA KD data indicates that the somite and inter-somitic arteries are more sensitive for metastatic colonization. Previous studies and our current accumulator data suggest these to be regions with higher oxidative stress, guiding insights for oxidative-mechanistic therapy. These and other conditional accumulations of sparse metastatic hotspots demonstrate the power of FishATLAS as a longitudinal assay of cellular and genetic conditions across all cancers.