The oral squamous cell carcinoma sublines, LN1-1 cells have been established by in vivo selection and showed higher abilities of lymphangiogenesis and lymph node metastasis in comparison with their parental OEC-M1 cells. After purified exosomes from cultured medium by differential centrifugation and analyzed using transmitted electron microscopy, dynamic light scattering and Western blot, LN1-1 cell-derived exosomes promoted LEC migration, tube formation and uptake by LECs than OEC-M1 cell-derived exosomes did. Using stable isotope labeling with amino acids in cell culture/liquid chromatography-tandem mass spectrometry based proteomic platform and confirmed by Western blot, Laminin &gamma2 was validated as one of highly expressed proteins in LN1-1-derived exosomes. Knockdown of Laminin &gamma2 impaired migration and tube formation of LECs as well as the exosomal uptake by LECs. Importantly, the silencing of Integrin &alpha3 but not Integrin &beta1, &beta4 and &alpha6 in LECs was able to sustain Laminin &gamma2-mediated exosomal uptake, suggesting a critical role of Integrin &slpha3 in Laminin &gamma2-rich exosome-mediated functions.
