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Interleukin (IL)-34 is a pro-inflammatory cytokine involved in tumor development. The role of IL-34 in the proliferation and epithelial-mesenchymal transition (EMT) of gastric cancer (GC) remains to be investigated.To investigate whether and how IL-34 affects the proliferation of GC cells and EMT.Using immunohistochemical staining, the expression of IL-34 protein was detected in 60 paired GC and normal paracancerous tissues and the relationship between IL-34 and clinicopathological factors was analyzed. The expression of IL-34 mRNA and protein in normal gastric epithelial cell lines and GC was detected using quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting, respectively. Stable IL-34 knockdown and overexpression in AGS cell lines were established by lentiviral infection and validated by qRT-PCR and western blotting. The cholecystokinin-8 assay, clone formation assay, cell scratch assay, and transwell system were used to detect GC cell proliferation, clone formation, migration, and invasion capacity, respectively. The effects of IL-34 on the growth of GC transplant tumors were assessed using a subcutaneous transplant tumor assay in nude mice. The effects of IL-34 on the expression level of EMT-associated proteins in AGS cells were examined by western blotting.Expression of IL-34 protein and mRNA was higher in GC cell lines than in GES-1 cells. Compared to matched normal paraneoplastic tissues, the expression of IL-34 protein was higher in 60 GC tissues, which was correlated with tumor size, T-stage, N-stage, tumor, node and metastasis stage, and degree of differentiation. Knockdown of IL-34 expression inhibited the proliferation, clone formation, migration, and invasion of AGS cells, while overexpression of IL-34 promoted cell proliferation, clone formation, migration, and invasion. Furthermore, the reduction of IL-34 promoted the expression of E-cadherin in AGS cells but inhibited the expression of vimentin and N-cadherin. Overexpression of IL-34 inhibited E-cadherin expression but promoted expression of vimentin and N-cadherin in AGS cells. Overexpression of IL-34 promoted the growth of subcutaneous transplanted tumors in nude mice.IL-34 expression is increased in GC tissues and cell lines compared to normal gastric tissues or cell lines. In GC cells, IL-34 promoted proliferation, clone formation, migration, and invasion by regulating EMT-related protein expression cells. Interference with IL-34 may represent a novel strategy for diagnosis and targeted therapy of GC.

Background:Members of the integrin β superfamily(ITGBs) have been shown to be aberrantly expressed in various human cancers and involved in tumorigenesis and progression. However, the diverse expression patterns and prognostic values of the entire ITGB family members in gastric cancer(GC) has not been systematically investigated.Methods:In the current study, Oncomine, GEPIA, Kaplan Meier plotter, TIMER, GeneMANIA, STRING and Metascape database were employed to explore the transcriptional and survival data of ITGB superfamily members in GC. Moreover, we confirmed the mRNA expression levels of ITGB superfamily members in GC cell lines by qRT-PCR.Results:The mRNA expression level of ITGB1/2/4/5/8 was upregulated in GC, while the expression level of ITGB7 was downregulated. Higher expression of ITGB2/7 was significantly associated with the tumor stage of patients with GC. However, we found that the expression level of ITGB1/2/4/5/6/7/8 was remarkably increased in GC cell lines compared to stomach normal cell lines, while ITGB3 expression was decreased in the former than in the latter. Meanwhile,higher expression levels of ITGB2/6/7 were closely correlated with better overall clinical survival (OS) and recurrence-free survival (RFS) in GC patients, while higher ITGB3/4/5 expression were strongly associated with poorer OS and RFS.We also discovered that the functions of ITGBs and their adjacent genes are mainly related to protein complexes involved in cell adhesion. the functions of ITGBs and their adjacent proteins are mainly related to focal adhesion, cell adhesion molecules, proteoglycans in cancer, small cell lung cancer, rap1 signaling pathway, IgA production by intestinal immune network, and microRNAs in cancer.In addition, the expression of ITGBs was significantly correlated with the infiltration of multiple immune cells, including B cells, CD8+ T cells, CD4+ T cells, neutrophils, macrophages, and dendritic cells.Conclusions:Our results suggested that abnormal expression of ITGBs plays a key role in the progression of GC and that ITGBs may be potential prognostic biomarkers and therapeutic targets for GC.