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In the stomach, strictly regulated cell adherens junctions are crucial in determining epithelial cell differentiation. Sonic Hedgehog (Shh) regulates epithehal cell differentiation in the adult stomach. We sought to identify whether Shh plays a role in regulating adherens junction protein E-cadherin as a mechanism for epithelial cell differentiation. Mouse nontumorigenic gastric epithelial (IMGE-5) cells treated with Hedgehog signaling inhibitor cyclopamine and anti-Shh 5E1 antibody or transduced with short hairpin RNA against Skinny Hedgehog (IMGE- 5ski) were cultured. A mouse model expressing a parietal cell-specific deletion of Shh (HKCre/ShhKO) was used to identify further changes in adherens and tight junctions. Inhibition of Hedgehog signaling in IMGE-5 cells caused loss of E-cadherin expression accompanied by disruption of F-actin cortical expression and relocalization of zonula occludens-1 (ZO-1). Loss of E-cadherin was also associated with increased proliferation in IMGE-5ski cells and increased expression of the mucous neck cell lineage marker MUC6. Compared with membrane-expressed E-cadherin and ZO- 1 protein in controls, dissociation of E-cadherin/β-catenin and ZO-1/occludin protein complexes was observed in HKCre/ShhKO mice. In conclusion, we demonstrate that Hedgehog signaling regulates E-cadherin expression that is required for the maintenance of F-actin cortical expression and stability of tight junction protein ZO-1. [ABSTRACT FROM AUTHOR]

Presents information on a study which examined the regulation of intercellular adhesion by hepatocyte growth factor (HGF) on a novel nontumorigenic gastric epithelial cell line (IMGE-5). Materials and methods; Preparation and culture of IMGE-5; Expression of HGF receptors by IMGE-5 cells.

Excessive signaling through gp130, the shared receptor for the interleukin (IL)6 family of cytokines, is a common hallmark in solid malignancies and promotes their progression. Here, we established the in vivo utility of bazedoxifene, a steroid analog clinically approved for the treatment of osteoporosis, to suppress gp130‐dependent tumor growth of the gastrointestinal epithelium. Bazedoxifene administration reduced gastric tumor burden in gp130Y757F mice, where tumors arise exclusively through excessive gp130/STAT3 signaling in response to the IL6 family cytokine IL11. Likewise, in mouse models of sporadic colon and intestinal cancers, which arise from oncogenic mutations in the tumor suppressor gene Apc and the associated β‐catenin/canonical WNT pathway, bazedoxifene treatment reduces tumor burden. Consistent with the proposed orthogonal tumor‐promoting activity of IL11‐dependent gp130/STAT3 signaling, tumors of bazedoxifene‐treated Apc‐mutant mice retain excessive nuclear accumulation of β‐catenin and aberrant WNT pathway activation. Likewise, bazedoxifene treatment of human colon cancer cells harboring mutant APC did not reduce aberrant canonical WNT signaling, but suppressed IL11‐dependent STAT3 signaling. Our findings provide compelling proof of concept to support the repurposing of bazedoxifene for the treatment of gastrointestinal cancers in which IL11 plays a tumor‐promoting role. Synopsis: Inhibition of gp130‐receptor/STAT3 activity confers anti‐tumor effects in mouse models of gastrointestinal cancers. This effect is recapitulated in mice treated with bazedoxifene, an FDA‐approved drug for osteoporosis treatment, supporting its repurposing as treatment in gastrointestinal cancers. First proof‐of‐concept demonstration that bazedoxifene, an FDA‐approved drug for postmenopausal osteoporosis, inhibits the growth of gastric and colon cancers using three independent mouse models.Mechanistically, this arises from the capacity of bazedoxifene to systemically inhibit gp130/STAT3 signalling as demonstrated in the gp130Y757F mouse model of intestinal‐type gastric cancer.This data provides a strong rationale to support future clinical efforts for repurposing bazedoxifene as an inhibitor of gp130/STAT3 signaling. Inhibition of gp130‐receptor/STAT3 activity confers anti‐tumor effects in mouse models of gastrointestinal cancers. This effect is recapitulated in mice treated with bazedoxifene, an FDA‐approved drug for osteoporosis treatment, supporting its repurposing as treatment in gastrointestinal cancers. [ABSTRACT FROM AUTHOR]