In Vivo Imaging of Tumor-Propagating Cells, Regional Tumor Heterogeneity, and Dynamic Cell Movements in Embryonal Rhabdomyosarcoma

SummaryEmbryonal rhabdomyosarcoma (ERMS) is an aggressive pediatric sarcoma of muscle. Here, we show that ERMS-propagating potential is confined to myf5+ cells and can be visualized in live, fluorescent transgenic zebrafish. During early tumor growth, myf5+ ERMS cells reside adjacent normal muscle fibers. By late-stage ERMS, myf5+ cells are reorganized into distinct regions separated from differentiated tumor cells. Time-lapse imaging of late-stage ERMS revealed that myf5+ cells populate newly formed tumor only after seeding by highly migratory myogenin+ ERMS cells. Moreover, myogenin+ ERMS cells can enter the vasculature, whereas myf5+ ERMS-propagating cells do not. Our data suggest that non-tumor-propagating cells likely have important supportive roles in cancer progression and facilitate metastasis.

► Functional heterogeneity of ERMS cells can be visualized in live zebrafish
► Tumor-propagating potential is restricted to myf5+ ERMS cells
► myogenin+ ERMS cells are highly invasive and colonize new areas of growth
► Metastatic and ERMS-propagating potential resides in distinct cell subpopulations