OCT3/4 enhances tumor immune response by upregulating the TET1-dependent NRF2/MDM2 axis in bladder cancer.

ABSTRACT

This study aimed to investigate the function of OCT3/4 on tumor immune escape in bladder cancer. Initially, the expression of OCT3/4, TET1, NRF2 and MDM2 was quantified in tumor tissues and cells, followed by gain- or loss-of-function studies to define their roles in cell migration, invasion and apoptosis and tumorigenicity in nude mice. Bladder cancer presented with abundant expression levels of OCT3/4, TET1, NRF2 and MDM2. We found that OCT3/4 promoted TET1 expression via binding to its promoter and that TET1 recruited MLL protein to NRF2 promoter and upregulated its expression, while NRF2 enhanced MDM2 expression. Upregulated MDM2 accelerated tumor immune escape in bladder cancer in mice. OCT3/4 knockdown suppressed the cell migration and invasion while inducing apoptosis, and consequently prevented tumor growth and immune escape in mice. Collectively, OCT3/4 may promote the progression of tumor immune escape in bladder cancer through acting as a promoter of the TET1/NRF2/MDM2 axis.