SOX9 is regulated by AURKA in response to Helicobacter pylori infection via EIF4E-mediated cap-dependent translation

Abstract

Helicobacter pylori (H. pylori) infection is the main risk factor for gastric cancer. The SRY-Box Transcription Factor 9 (SOX9) serves as a marker of stomach stem cells. We detected strong associations between AURKA and SOX9 expression levels in gastric cancers. Utilizing in vitro and in vivo mouse models, we demonstrated that H. pylori infection induced elevated levels of both AURKA and SOX9 proteins. Notably, the SOX9 protein and transcription activity levels were dependent on AURKA expression. AURKA knockdown led to a reduction in the number and size of gastric gland organoids. Conditional knockout of AURKA in mice resulted in a decrease in SOX9 baseline level in AURKA-knockout gastric glands, accompanied by diminished SOX9 induction following H. pylori infection. We found an AURKA-dependent increase in EIF4E and cap-dependent translation with an AURKA-EIF4E-dependent increase in SOX9 polysomal RNA levels. Immunoprecipitation assays demonstrated binding of AURKA to EIF4E with a decrease in EIF4E ubiquitination. Immunohistochemistry analysis on tissue arrays revealed moderate to strong immunostaining of AURKA and SOX9 with a significant correlation in gastric cancer tissues. These findings elucidate the mechanistic role of AURKA in regulating SOX9 levels via cap-dependent translation in response to H. pylori infection in gastric tumorigenesis.