Long-Term Helicobacter pylori Infection Switches Gastric Epithelium Reprogramming towards Cancer Stem Cell-Related Differentiation Program in Hp-Activated Gastric Fibroblast-TGFβ Dependent Manner

Abstract

<i>Helicobacter pylori</i> (<i>Hp)</i>-induced inflammatory reaction leads to a persistent disturbance of gastric mucosa and chronic gastritis evidenced by deregulation of tissue self-renewal and local fibrosis with the crucial role of epithelial-mesenchymal transition (EMT) in this process. As we reported before, <i>Hp</i> activated gastric fibroblasts into cells possessing cancer-associated fibroblast properties (CAFs), which secreted factors responsible for EMT process initiation in normal gastric epithelial RGM1 cells. Here, we showed that the long-term incubation of RGM1 cells in the presence of <i>Hp</i>-activated gastric fibroblast (<i>Hp</i>-AGF) secretome induced their shift towards plastic LGR5⁺/Oct4^high/Sox-2^high/c-Myc^high/Klf4^low phenotype (l.t.EMT⁺RGM1 cells), while <i>Hp</i>-non-infected gastric fibroblast (GF) secretome prompted a permanent epithelial-myofibroblast transition (EMyoT) of RGM1 cells favoring LGR<b>^-</b>/Oct4^high/Sox2^low/c-Myc^low/Klf4^high phenotype (l.t.EMT<b>^-</b>RGM1 cells). TGFβ1 rich secretome from <i>Hp</i>-reprogrammed fibroblasts prompted phenotypic plasticity and EMT of gastric epithelium, inducing pro-neoplastic expansion of post-EMT cells in the presence of low TGFβR1 and TGFβR2 activity. In turn, TGFβR1 activity along with GF-induced TGFβR2 activation in l.t.EMT<b>^-</b>RGM1 cells prompted their stromal phenotype. Collectively, our data show that infected and non-infected gastric fibroblast secretome induces alternative differentiation programs in gastric epithelium at least partially dependent on TGFβ signaling. <i>Hp</i> infection-activated fibroblasts can switch gastric epithelium microevolution towards cancer stem cell-related differentiation program that can potentially initiate gastric neoplasm.