Acute pancreatitis (AP) is hypothesized to be related to the activation of an inflammatory response induced by pyroptosis. The aim of the present study was to investigate the potential role of tumor necrosis factor receptor‑associated factor 6 (TRAF6) in pyroptosis in an AP rat model and the human pancreatic ductal epithelial HPDE6C7 cell line. In vivo, AP was induced by intraperitoneal injection of caerulein (CAE) in rats. The rats were sacrificed at 24 or 48 h after the final CAE injection. In vitro, HPDE6C7 cells were treated with CAE for 12, 24 and 48 h. Moreover, TRAF6 was overexpressed and treated with CAE for 48 h. Histopathological changes of pancreatic, serum and supernatant inflammatory cytokines and pyroptosis‑related mRNA and protein expression levels were determined by histopathological scores, ELISA, reverse transcription‑quantitative PCR and western blotting. In addition, pyroptosis morphological changes were also determined by Hoechst/PI staining in HPDE6C7 cells. Results showed that AP was observed in the CAE‑induced rat model, and that serum IL‑1β and IL‑18 levels, and TRAF6, NLR pyrin domain containing 3 (NLRP3), caspase‑1 and caspase‑3 mRNA and protein expression levels were increased. Similar in HPDE6C7 cells, CAE treatment caused supernatant IL‑1β level, NLRP3 and caspase‑1 mRNA expression levels to significantly increase. After TRAF6 overexpression and CAE treatment, supernatant IL‑1β level, caspase‑1 protein expression level, and NLRP3 and caspase‑3 mRNA and protein expression levels were also significantly increased. Furthermore, cells exhibited red fluorescence in Hoechst/PI staining, which can be used as a method of detecting pyroptosis activation. The results also showed that the red fluorescence was stronger after CAE treatment or TRAF6 overexpression plus CAE treatment. In conclusion, TRAF6 and caspase‑1/3 signaling pathways were involved in the pathogenesis of CAE‑induced AP in rats. Pyroptosis was activated by CAE and TRAF6 overexpression via the caspase‑1/3 signaling pathways in HPDE6C7 cells.

The present study investigated the effects and molecular mechanism of the second mitochondria‑derived activator of caspase (SMAC) mimetic birinapant on the proliferation and apoptotic rate of liver cancer cells. Western blotting and reverse transcription‑quantitative PCR were used to detect the protein and mRNA expression levels of cellular inhibitor of apoptosis 1 (cIAP1) and tumor necrosis factor receptor‑associated factor 3 (TRAF3) in the liver cancer cell lines Huh7, H22 and HepG2, and the hepatocyte line AML12. Annexin V‑FITC and Transwell assays were used to assess the effect of birinapant pretreatment on the apoptotic rate and invasive ability of liver cancer cells. Lentivirus‑mediated silencing of TRAF3 was performed in liver cancer cells. Western blotting was used to detect the lentivirus silencing efficiency. A subcutaneous hepatocellular carcinoma model was established in nude mice and 15 days after tumor induction the subcutaneous tumors were measured in each group. Immunohistochemistry assays were used to detect the protein expression levels of proliferating cell nuclear antigen and caspase‑3. The results suggested that the expression levels of cIAP1 and TRAF3 were lower in Huh7, H22 and HepG2 cells compared with AML12 cells. Pretreatment with birinapant promoted apoptosis and inhibited invasion of liver cancer cells by activating the cIAP1/TRAF3 axis. Birinapant also promoted apoptosis and inhibited the growth of subcutaneous hepatocellular carcinoma tumors in nude mice. The present results suggested that the SMAC mimetic birinapant may promote apoptosis, and inhibit the proliferation and invasion of liver cancer cells. The molecular mechanism responsible for the effects of birinapant may be related to activation of the cIAP1/TRAF3 signaling pathway by birinapant in liver cancer cells.

The aim of the present study was to investigate the involvement of B cell‑activating factor (BAFF) in the pathogenesis of IgA nephropathy by activating the tumor necrosis factor receptor‑associated factor 6 (TRAF6)/NF‑κB signaling pathway in glomerular mesangial cells. For the clinical analysis, blood, urine and kidney tissue samples were collected from 58 patients diagnosed with primary IgA nephropathy by renal biopsy. For the in vitro study, glomerular mesangial cells were divided into five groups: Control (con)‑short hairpin RNA (shRNA) (control group); con‑shRNA + BAFF (20 ng/ml); con‑shRNA + BAFF + BAFF‑RFc chimera protein (500 µg/ml); TRAF6‑shRNA; and TRAF6‑shRNA + BAFF (20 ng/ml). For the in vivo experiments, 60 Sprague‑Dawley rats were randomly divided into four groups: Con‑small interfering RNA (siRNA) (control group); con‑siRNA + IgA (IgA nephropathy group), BAFF‑RFc chimera protein (2 µg/ml) + IgA, and TRAF6‑siRNA (0.2 µM) + IgA. Reverse transcription‑quantitative PCR was performed to evaluate the mRNA expression levels of TRAF6, connective tissue growth factor (CTGF), fibronectin (FN) and NF‑κBP65. Western blot analysis was used to detect the protein expression levels of TRAF6, FN, CTGF and phosphorylated‑NF‑κBP65 in glomerular mesangial cells and kidney tissues. The results revealed that plasma BAFF levels were positively correlated with the severity of pathological damage in patients with IgA nephropathy. In vitro, BAFF induced the mRNA and protein expression of TRAF6, CTGF, FN and NF‑κBP65 in glomerular mesangial cells. After the BAFF‑RFc chimera protein was added to inhibit the binding of BAFF and BAFF‑receptor (‑R), this effect was reduced. In vivo, inhibition of the effects of BAFF via injection with the BAFF‑R Fc chimera protein reduced kidney damage in rats suffering from IgA nephropathy. The effect on the expression of signaling pathway‑associated proteins was also alleviated. In conclusion, BAFF enhanced the expression of fibroblast factors in the kidneys by activating the TRAF6/NF‑κB signaling pathway.