B7 Induces Apoptosis in Colorectal Cancer Cells by Regulating the Expression of Caspase-3 and Inhibits Autophagy

Low extracellular pH enhances TRAIL-induced apoptosis by downregulating Mcl-1 expression

We previously reported that low extracellular pH promotes tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis through the mitochondria-mediated caspase signal transduction pathway. In this study, we further investigated the mechanism of low extracellular pH on TRAIL-induced apoptosis. When human colorectal carcinoma HCT116 cells were treated with TRAIL for 4 h, significant cytotoxicity was observed at pH 6.3, while cytotoxic effects were notably reduced at pH 7.2. These findings suggest that TRAIL's cytotoxic effects on human colorectal cancer cells are enhanced in low pH environments following TRAIL treatment. Similar results were observed in human pancreatic adenocarcinoma BxPC-3 cells. Interestingly, TRAIL was found to downregulate the levels of anti-apoptotic proteins, such as Mcl-1. This was confirmed by the knock-in (KI) of an Mcl-1 phosphorylation site mutant in HCT116 cells, which blocked TRAIL-induced Mcl-1 downregulation and the subsequent apoptotic response. These results indicate that Mcl-1 mediates TRAIL resistance in the Mcl-1 KI cells. Additionally, our results revealed that TRAIL significantly induced JNK phosphorylation in HCT116 cells, suggesting the involvement of JNK in TRAIL-induced cell death in colorectal cancer cells. Our findings demonstrate that low extracellular pH enhances TRAIL-induced cytotoxicity, particularly at pH 6.3 and 6.6. Moreover, the anti-apoptotic Bcl-2 family member Mcl-1 is an important target of TRAIL in colorectal carcinoma HCT116 cells under different low pH conditions. TRAIL triggered a rapid decline in Mcl-1, suggesting that Mcl-1 downregulation is crucial for TRAIL-induced apoptosis.

The critical role of RAGE in severe influenza infection: A target for control of inflammatory response in the disease

Controlling the excessive inflammatory response is one of the key ways to reduce the severity and mortality of severe influenza virus infections. RAGE is involved in inflammatory responses and acute lung injuries. Here, we investigated the role of RAGE and its potential application as a target for severe influenza treatment through serological correlation analysis for influenza patients, and treatment with the RAGE inhibitor FPS-ZM1 on A549 cells or mice with influenza A (H1N1) infection. The results showed high levels of RAGE were correlated with immunopathological injury and severity of influenza, and FPS-ZM1 treatment increased the viability of A549 cells with influenza A infection and decreased morbidity and mortality of influenza A virus infection in mice. The RAGE/NF-κb inflammatory signaling pathway is a major targeting pathway for FPS-ZM1 treatment in severe influenza. These findings provide further insights into the immune injury of severe influenza and a potential targeting candidate for the disease treatment.