[ ABSTRACT] AIM:To investigate the effect of DEK downregulation on the apoptosis of gastric carcinoma SGC-7901 cells, and to explore its associations with NF-κB signaling pathway and apoptosis related proteins.METHODS:SGC-7901 cells with different treatments were divided into 3 groups including untreated group, control siRNA group and DEK siRNA group.The expression of DEK at mRNA and protein levels in the SGC-7901 cells was detected by real-time PCR and Western blot.The cell apoptosis was examined by flow cytometry.Furthermore, the activities of caspase-3 and caspase-9 in the SGC-7901 cells were investigated by Caspase-Glo?-3/9 kit.Finally, the expression of key regulatory pro-tein p65 of NF-κB signaling pathway and apoptosis-related proteins Bcl-2 and Bax in the SGC-7901 cells was investigated by Western blot.RESULTS:Compared with untreated group and control siRNA group, the expression of DEK at mRNA and protein levels was significantly downregulated in DEK siRNA group (P<0.05).In addition, the ratios of early phase apoptosis and total apoptosis in DEK siRNA group were markedly higher than those in untreated group and control siRNA group (P<0.05).Most notably, the decrease in p65 and Bcl-2 proteins, increase in Bax protein and the increases of caspase-3 and caspase-9 activities were observed in DEK siRNA group.CONCLUSION:Downregulation of DEK mediates cell apoptosis of gastric carcinoma may be tightly associated with NF-κB signaling pathway.

Objective The objective of this study was to investigate the expression of interleukin-38(IL-38)in patients with breast cancer and its regulatory function to CD8+T cell activity.Methods 44 patients with breast cancer,25 patients with benign breast tumor,and 20 controls,who were treated in the First Affiliated Hospital of Xinxiang Medical University from July 2020 and Sep-tember 2022.Mononuclear cells from plasma and peripheral blood of all subjects were isolated,tumor-infiltrating lymphocytes from tumor tissues of breast cancer patients were isolated,and CD8+T cells were purified.IL-38 protein level in the plasma was measured by enzyme-linked immunosorbent assay(ELISA).The relative level of IL-38 mRNA in the tissue was semi-quantified by real-time quantitative PCR.Recombinant human IL-38 was used to stimulate CD8+T cells from peripheral blood and tumor tissue from patients with breast cancer.A co-culture system was established between CD8+T cells and breast cancer MCF-7 cell line.The percentage of target cell death was calculated by measuring lactate dehydrogenase level in the supernatants.The levels of perforin,granzyme B,inter-feron-γ and tumor necrosis factor-α(TNF-α)in the supernatants were measured by ELISA.The immune checkpoint molecules ex-pression in CD8+T cells were detected by flow cytometry.Results The levels of plasma IL-38 were significantly higher in patients with breast cancer(74.23±19.88 pg/mL)compared with in patients with benign breast tumor(62.87±16.27 pg/mL,P=0.018)and controls(61.77±12.75 pg/mL,P=0.013).The relative expression of IL-38 mRNA in tumor tissues was significantly higher than in para-tumor tissues(1.57±0.22 vs.1.00±0.18,P<0.001).The proportion of target cell death induced by peripheral and tumor-in-filtrating CD8+T cells,and the levels of perforin and granzyme B secretion in direct contact co-culture group were higher than those in indirect contact co-culture group(P<0.05).There were no significant differences of either interferon-γ or TNF-α levels between di-rect contact and indirect contact co-culture group(P>0.05).In the direct contact co-culture group,the levels of target cell death pro-portion,perforin,granzyme B,interferon-γ and TNF-α l in the IL-38 stimulation group were lower than those in the non-stimulation group(P<0.05).In the indirect contact co-culture group,the target of cell death proportion,interferon-γ and TNF-α the IL-38 stimulation group were also lower than those in the non-stimulation group(P<0.05).However,there were no statistical differences of either perforin or granzyme B levels between the IL-38 stimulation group and non-stimulation group within the indirect contact co-culture group(P>0.05).There were also no differences in the levels of immune checkpoint molecules in CD8+T cells between the non-stimulation group and the IL-38 stimulation group(P>0.05).Conclusion Highly expressed IL-38 in patients with breast cancer may be involved in inducing CD8+T cell functional failure.