Abstract:Background and Aims In the influence and regulation of the tumor microenvironment, certain non-tumor cells play crucial roles in tumor metastasis through exosomes. Studies have indicated that in pancreatic cancer, a high-glucose microenvironment can promote its invasion and metastasis. The liver, being a vital organ for glucose metabolism, is also a common site for pancreatic cancer metastasis, yet the mechanisms underlying pancreatic cancer liver metastasis remain unclear. Therefore, this study was conducted to investigate the effect of exosomes secreted by liver cells under high-glucose condition on the invasion and migration of pancreatic cancer cells and the possible mechanism.Methods Immortalized liver cells MIHA were cultured in either high-glucose or normal glucose media, and exosomes were extracted from the supernatant. The exosomes from both medium sources were identified using transmission electron microscopy, particle size analysis, and Western blot. Exosomes from both medium sources were labeled with fluorescent dye PKH67 and co-cultured with pancreatic cancer cells PANC-1 labeled with fluorescent dye DAPI, and then the uptake of exosomes by PANC-1 cells was observed using real-time laser scanning confocal microscopy. PANC-1 cells were co-cultured with exosomes derived from high-glucose medium (high-glucose group) or normal glucose medium (normal glucose group), with PANC-1 cells cultured without exosomes serving as a negative control group. Subsequently, wound-healing assay and Transwell assay were performed to assess the migration and invasion abilities of PANC-1 cells in each group, and Western blot was used to detect the expression of epithelial-mesenchymal transition (EMT)-related proteins E-cadherin and N-cadherin in PANC-1 cells.Results Transmission electron microscopy showed the extraction of numerous spherical vesicles with lipid bilayer membrane structures from the supernatant of MIHA cells cultured in both media, with diameters ranging from 40-150 nm. Western blot revealed positive expression of exosome marker proteins CD9 and CD63 in the extracts. Real-time laser scanning confocal microscopy demonstrated the uptake of exosomes from both medium sources by PANC-1 cells. Wound-healing assay and Transwell assay showed that the migration rate, number of migrating cells, and number of invading cells in the high-glucose group were significantly higher than those in the negative control group (all P<0.05). Western blot results showed a significant decrease in E-cadherin protein expression and a significant increase in N-cadherin protein expression in PANC-1 cells in the high-glucose group compared to the negative control group (all P<0.05). There were no statistically significant differences in all parameters between the normal glucose group and the negative control group (all P>0.05).Conclusion Exosomes derived from hepatocytes under high-glucose environment can promote the invasion and migration of pancreatic cancer cells, and the mechanism of action may be associated with regulating the expression of EMT-related proteins in pancreatic cancer cells.