Abstract: Objective: To treat oral squamous cell carcinoma through via exosomes loaded with miRNA34a. Methods: First, exosomes ought to be extracted from the culture supernatants of HEK293 cells by means of ultracentrifugation and identified through integrating transmission electron microscopy, nanoparticle tracking analyzer (NTA) with Western blotting experiment, to load miRNA34a mimics modified by hydrophobicity into exosomes by utilizing the method of co-incubation, and to fabricate exo-miRNA34a for loading efficiency observation under an inverted fluorescence microscope. Second, exo-miRNA34a will be inoculated into HN6 cells, so that the up-taking ability of HN6 cells on exosomes will be observed via laser scanning confocal microscope, and the proliferation changes of HN6 cells will be also detected coupled with CCK-8 experiment. Results: Small vesicles of 40-150 nm in size will be observed under a transmission electron microscopy in culture supernatant fluid extract of HEK293 cells, the distribution maxima of particle size of the vesicles is 97.9 nm based on the observation results of NTA, and surface protein, TSG101 and CD63, of exosomes can be detected by the transmission electron microscopy. However, plasmosin- Calnexin turns out negative after detection, which verifies the successful extraction of exosomes. Furthermore, the observation results of fluorescence microscope show that miRNA34a mimics modified by hydrophobicity can be loaded into exosomes effectively during co-incubation, drug loading capacity is 47% approximately. The particle size of exosomes increases after drug loading, and its integrity is not affected. Besides, laser scanning confocal microscope displays that exo-miRNA34a enters into HN6 cells, CCK-8 detection finds that miRNA34a can inhibit the proliferation of HN6 cells obviously (P＜0.05). Conclusion: MiRNA34a mediated by exosomes can significantly inhibit the proliferation of HN6 cells in oral squamous cell carcinoma.

Key words: miRNA34a, ?exosomes, ?oral squamous cell carcinoma, ?proliferation, ?HEK293 cells, ?HN6 cells