Abstract: Objective: To investigate the effects of cervical cancer HeLa cell exosomes on the migration, invasion and Wnt/β-catenin signaling pathway of the cells, and to elucidate the possible mechanism of the exosomes in the occurrence and development of cervical cancer. Methods: The cervical cancer HeLa cells in the logarithmic growth phase were selected. The cervical cancer HeLa cell exosomes were isolated by ultracentrifugation. The morphology of isolated exosomes was observed under transmission electron microscope(TEM). Western blotting method was used to detect the expressions of exosomal marker proteins CD63 and CD81, and the isolated exosomes were identified. The HeLa cells were divided into exosomes group(Exo group) and control group. The cells in two groups were cultured separately with medium containg HeLa cell exosomes or not. The uptake of exosomes by HeLa cells was observed with confocal microscope, the exosomes were labeled with PKH26 fluorescence, and the nuclei of HeLa cells were stained with DAPI fluorescence. Transwell chamber was used to measure the cell invasion ability.Cell scratch assay was used to measure the cell migration ability.Western blotting method was used to measure the expression levels of Wnt1, β-catenin and T cell factor 4 (TCF4) proteins in the cells. Results: The TEM results showed cylindrical or oval vesicle bodies with a diameter of 40-100 nm and rich in CD63 protein and CD81 protein. The confocal microscope results showed that there was exosomal attachment on the membrane surface of HeLa cells in Exo group,but there was no exosomal attachment on the membrane surface of the HeLa cells in control group; The Transwell assay results showed that the number of invasion HeLa cells in Exo group was significantly higher than that in control group(t=17.894,P<0.01);the scratch assay results showed that the migration distance of the cells in Exo group was significantly longer than that in control group(t=9.689,P<0.01).The Western blotting results showed the expression levels of Wnt/β-catenin signaling pathway-related proteins Wnt1, β-catenin and TCF4 in the HeLa cells in Exo group were significantly higher than those in control group(t=13.159,P<0.01;t=15.478,P<0.01;t=7.734,P<0.01). Conclusion: The HeLa cell-derived exosomes can promote the invasion and migration abilities of cervical cancer cells. The mechanism may be related to that the HeLa cell-derived exosomes can promote the activation of Wnt/β-catenin signaling pathway and the downstream TCF4 gene expression.

Key words: cervical cancer, exosomes, migration, invasion, Wnt/β-catenin signaling pathway, T cell factor 4