Extracellular vesicles isolated from SphK1 inhibitor SKI II-medium restrain the migration of colorectal cancer.

BACKGROUND: Colorectal cancer is a chronic disease particularly detrimental to human health. Although there have been many studies on colorectal cancer and extracellular vesicles (EVs), it is unknown whether SKI II, an inhibitor of sphingosine kinase 1 (SphK1), uses EVs as transporters to inhibit colorectal cancer migration. This research aimed to investigate whether EVs, which were isolated from SphK1 inhibitor SKI II-medium, affected on E-cadherin and vimentin and the cell migration of colorectal cancer cells. METHODS: EVs were extracted from RKO cells using an exosome extraction and purification kit, and the extracted EVs were identified to evaluate whether the EVs extracted by this kit met the experimental requirements. (RKO)EVs were extracted from RKO exosom-free serum culture medium, and (RKO-SK)EVs were extracted from RKO exosom-free serum culture medium with SKI II intervention. PKH67-labeled EVs were added to the cells. EVs inhibitor GW4869, (RKO)EVs, and (RKO-SK)EVs were used to intervene in RKO cells, and (RKO)EVs and (RKO-SK)EVs were used to intervene in HT29 cells. The E-cadherin and vimentin expression were tested by western blotting. Transwell assay was used to detect cell migration ability. RESULTS: Compared with the control group, after GW4869 treatment, E-cadherin was increased, vimentin was decreased, and the number of migrating cells was decreased. After (RKO)EVs intervention, the expression of E-cadherin, vimentin and cell migration number were opposite. Compared with (RKO)EVs intervention in RKO cells, E-cadherin was increased, vimentin was decreased and the number of migrating cells decreased after (RKO-SK)EVs intervention. Similarly, compared with (RKO)EVs intervention in HT29 cells, after (RKO-SK)EVs intervention, E-cadherin was increased, vimentin was decreased, and the number of migrating cells decreased. CONCLUSIONS: EVs isolated from SphK1 inhibitor SKI II-medium affect E-cadherin and vimentin expression in colorectal cancer and inhibit cell migration.