Peroxiredoxin 1 inhibits autophagy through interacting with Rab7 in human dysplastic oral keratinocyte cells.

Objective: As a major risk factor for oral leukoplakia (OLK), oxidative stress can induce intracellular reactive oxygen species (ROS), which is closely related to autophagy. Ras-related protein 7 (Rab7) is an important molecule involved in autophagy. Peroxiredoxin 1 (Prx1) is a key antioxidant protein, overexpressed in a variety of malignant tumors. We found that the expression of Prx1 in OLK was up-regulated, and Prx1 is associated with autophagy. This study aims to identify mechanisms of Prx1 in oxidative stress associated autophagy in human dysplastic oral keratinocyte (DOK) cells.

Design: Hydrogen peroxide (HO) was used to induce autophagy in DOK cells. CCK8 assay and flow cytometry were conducted to examine cell viability, cell apoptosis and intracellular ROS level. Autophagy-associated proteins were detected by western blot and immunofluorescence. MHY1485 was applied to investigate the role of Prx1 in autophagy. On the basis of online docking tool Zdock, Prx1 interacting with Rab7 was verified by immunofluorescence double-staining, Duolink PLA, and Co-immunoprecipitation (Co-IP).

Results: HO induced autophagy and ROS increase in DOK cells, and the expression of Prx1 increased gradually according to HO concentration Prx1 knockdown attenuated the inhibition of MHY1485 on the expressions of autophagy-related proteins and the ratio of LC3 II/LC3 I induced by HO. Moreover, Prx1 interacted with Rab7 in DOK cells.

Conclusions: Prx1 was involved in the regulation of HO-induced autophagy in DOK cells partly by physically interacting with Rab7. Prx1 knockdown promoted autophagy maybe by releasing more Rab7 into the autophagy process.