Mutual amplification of HNF4α and IL-1R1 composes an inflammatory circuit in Helicobacter pylori associated gastric carcinogenesis

Helicobacter pylori (Hp) is an environmental inducer of gastritis and gastric cancer (GC). The immune response to Hp and the associated changes in somatic gene expression are key determinants governing the transition from gastritis to GC. We show that hepatocyte nuclear factor 4 alpha (HNF4 alpha) is upregulated by Hp infection via NF-kappa B signaling and that its protein and mRNA levels are elevated in GC. HNF4 alpha in turn stimulates expression of interleukin-1 receptor 1(IL-1R1), which amplifies the inflammatory response evoked by its ligand IL-1 beta. IL-1 beta/IL-1R1 activates NF-kappa B signaling, thereby increasing HNF4 alpha expression and forming a feedback loop that sustains activation of the NF-kappa B pathway and drives the inflammation towards GC. Examination of clinical samples revealed that HNF4 alpha and IL-1R1 levels increase with increasing severity of Hp-induced gastritis and reach their highest levels in GC. Co-expression of HNF4 alpha and IL-1R1 was a crucial indicator of malignant transformation from gastritis to GC, and was associated with a poorer prognosis in GC patients. Disruption of the HNF4 alpha/IL-1R1/IL-1 beta/NF-kappa B circuit during Hp infection maybe an effective means of preventing the associated GC.