Conclusion
The pathological ECs differed significantly, both phenotypically and functionally, from the normal corresponding tissue, thus influencing their microenvironment cross-talk. The gene expression profile confirms the EndMT phenotype of tumor-derived ECs and migratory properties acquisition. Moreover, it indicates the role of miR-200b-3p, that is, regulating EndMT in pathological ECs and silencing several angiogenic growth factors and their receptors by directly targeting their mRNA transcripts.
Results
Hypoxia influences EC migration properties in wound healing assays. In hypoxia, healthy ECs migrate slower than they do in normoxia, as opposed to HBCa.MEC, where no decreased migration ability is induced by hypoxia due to EndMT features. NGS data identified this process to be altered in cancer ECs through extracellular matrix (ECM) organization. The deregulated genes, validated by qPCR, included SPP1, ITGB6, COL4A4, ADAMST2, LAMA1, GAS6, PECAM1, ELN, FBLN2, COL6A3, and COL9A3. NGS also identified collagens, laminins, fibronectins, and integrins, as being deregulated in tumor-derived ECs. Moreover, the analysis of the 10 most intensively modified miRNAs, when breast tumor-derived ECs were compared to healthy ECs, shed light on miR-200b-3p, which is strongly upregulated in HBCa.MECs when compared to HBH.MECs.