Figure 6

Carcinoma-derived exosomal TSP1 promotes the transendothelial migration of tumor cells in zebrafish. (A) Effect of exosomes derived from breast cancer cells on the expression of VE-cadherin, ZO-1 and CD146 mRNAs. Exosomes derived from MDA-MB-231 cells were injected into 48 h post fertilization (hpf) zebrafish embryos. At 48 h after the exosome injection, 30 embryos injected with exosomes and 30 control embryos were collected for mRNA level analysis by qRT-PCR. (B) Fluorescence imaging of the breast cancer cell migration in zebrafish. Dio-labeled breast cancer cells were injected into the yolk sac of zebrafish. Arrowheads indicate disseminated tumor foci (single tumor cells or cell aggregates) in the tail regions. Scale bar, 500 μm. (C) Quantitative analyses of the breast cancer cells located within the zebrafish tail region. (D) Proportion of zebrafish with the tumor cells migrated to the tail (%). Data are shown as mean ± SD and representative of three independent experiments. * p < 0.05, ** p < 0.01, *** p < 0.001; ns, no significance by unpaired Student’s t-test.