Exosome isolation from CM of OSCC cell lines. a. Freshly isolated exosomes were diluted 1:1000 for nanoparticle tracking analysis using Nanosight technology. The curve of the graph illustrated that the majority of exosomes were distributed with a peak at size 103 nm for SCC25-Exosoems and 112 nm for Cal27-Exosomes. Three independent experiments were performed, and results were merged into one curve. b. Bands represented the immunoblotting analysis of human Alix, CD63, CD9, and Rab5 on whole cell lysates and exosome lysates isolated from SCC25 and Cal27. c. Uptake of exosomes by THP-1-derived and PBMCs derived macrophages. Macrophages were labeled with 488-Phalloidin (green), exosomes with Exo-Red (Red), and Nuclei with DAPI (Blue), bar = 25 μm. Negative control was presented in Additional file 3. D. Transcription levels of TNFα, IL1β, and IL6 in THP-1-derived and PBMCs derived macrophages educated by conditioned media, exosome supernatant or conditioned media without exosomes from SCC25 and Cal27 for 24 h. Data were represented as the mean ± SD of three independent experiments.