Previous studies have established the important role of MIF in the development of pancreatic ductal adenocarcinoma (PDAC) for both therapeutic and diagnostic perspectives, but little is known about the expression and function of D-dopachrome tautomerase (DDT), a functional homolog of MIF, in PDAC. In the present study, we demonstrated that DDT was over-expressed in PDAC tissues in a pattern correlated with MIF. In the pancreatic cancer cell lines, PANC-1, BXPC-3 and ASPC-1, both DDT and MIF were expressed and co-localized with each other in the endosomal compartments and plasma membrane. Knockdown of DDT and MIF in PANC-1 cells cooperatively inhibited ERK1/2 and AKT phosphorylation, increased p53 expression, and reduced cell proliferation, invasion and tumor formation. These effects were rescued by the re-expression of MIF or DDT, but not by the forced expression of the tautomerase-deficient mutants of DDT and MIF, P1G-DDT and P1G-MIF. Finally, we observed that 4-iodo-6-phenylpyrimidine (4-IPP), a covalent tautomerase inhibitor of both DDT and MIF, attenuated PANC-1 cell proliferation and colony formation in vitro and tumor growth in vivo. Thus, targeting the tautomerase sites of both MIF and DDT may offer more efficient therapeutic benefits to PDAC patients.

Traumatic brain injury (TBI) is one of the leading causes of mortality and morbidity in adults and children worldwide. Recent studies have demonstrated that both apoptosis and autophagy participate in TBI-induced neuronal cell death and functional loss. The peroxisome proliferator-activated receptor-γ (PPAR-γ) agonist rosiglitazone (RSG) is a well-known anti-inflammatory, which carries out its effects via the activation of PPAR-γ. Previous studies have suggested that RSG may exert neuroprotective effects in animal models of both chronic and acute brain injury; however, whether RSG is involved in autophagic neuronal death following TBI remains to be elucidated. The present study aimed to determine whether RSG carries out its neuroprotective properties via the attenuation of neuronal apoptosis and autophagy, following TBI in a rat model. Furthermore, the role of RSG was investigated with regards to the modulation of inflammation and glutamate excitotoxicity, and the impact of RSG on functional recovery following TBI was determined. The rats were subjected to controlled cortical impact injury, prior to being randomly divided into three groups: A sham-operated group, a TBI group, and an RSG treatment group. The RSG treatment group was intraperitoneally treated with 2 mg/kg RSG immediately after TBI. The results of the present study demonstrated that RSG treatment following TBI significantly reduced neuronal apoptosis and autophagy, and increased functional recovery. These effects were correlated with a decrease in the protein expression levels of tumor necrosis factor α and interleukin-6. However, no significant changes were observed in the protein expression levels of glutamate transporter-1 in the brain cortex. The results of the present study provide in vivo evidence that RSG may exert neuroprotective effects via the inhibition of neuronal apoptosis and autophagy following experimental TBI in rats, and the mechanism underlying these effects may be associated with the anti-inflammatory action of RSG. The present study offers a novel insight into the potential use of RSG as a neuroprotective agent for the treatment of cerebral injuries.

Glioma is the most common malignant tumors in adult brains, and Notch signaling pathway plays an important role in cell differentiation. The aim of the present study is to investigate the role of Notch1 in the progression of glioma cancers and clarify the mechanism of Notch1 silencing on inhibiting the proliferation of glioma cancer cells. First, endogenous Notch1 expression was interfered with a lentiviral vector of Notch1 shRNA. RT-PCR and western blotting were used for detecting the expression of Notch1 mRNA and protein, respectively. MTT assay results demonstrated that transfection with Notch1 shRNA and treatment with MRK003, a Notch1 inhibitor, both inhibited the proliferation of glioma cancer cells (p < 0.01). The lentiviral vector of Notch1 shRNA transfected into U251 cells induced cell cycle arrest at G0/G1 phase by FACS with PI staining analysis. Meanwhile, the expression levels of LC3-II and Beclin1 significantly increase in Notch1 shRNA-transfected U251 cells, suggesting that cell autophagy was induced when interfering with Notch1 in glioma cells. The downstream transcription factors were also detected by RT-PCR and western blotting analysis, and the data showed that interference with Notch1 increased the expression level of Hes-1, but not Hes-5. Taken together, all the data obviously revealed that Notch1 played an important role in the progression of glioma cancers. The clarification of the mechanism will be helpful for the diagnosis of glioma cancer and would provide new clues to molecular targets for cancer therapy.

Epithelial-mesenchymal transition (EMT) is a pivotal event in tumor progression during which cancer cells undergo dramatic changes acquiring highly invasive properties. In this study, we found that nobiletin, a polymethoxylated flavone, suppressed migration and invasion in both U87 and U251 glioma cells. Expression of epithelial markers (E-cadherin and occludin) was upregulated; mesenchymal markers (N-cadherin, fibronectin) and the transcriptional factor Slug were downregulated after nobiletin treatment. Transforming growth factor β (TGF-β) was applied to stimulate EMT and the results showed that nobiletin not only influenced basal level cell migration but also prevented TGF-β-triggered migration and EMT, with the AKT/GSK3β/β-catenin signaling pathway greatly involved. Furthermore, nobiletin remarkably diminished TGF-β-induced β-catenin nuclear translocation and the binding to the Slug promoter. It is worth noting that nobiletin almost blocked invasion in Slug-expressing U87 and U251 cells, and only exhibiting faint effect on non-Slug-expressing U343 glioma cells. Reinforced Slug expression in U343 cells by transfecting Slug plasmid was significantly attenuated by nobiletin, demonstrating the essential role of Slug in the anti-metastasis effect of nobiletin. Nobiletin repressed tumor growth in vivo and abrogated EMT in nude mice bearing U87-Luc xenografts, as demonstrated by Xenogen IVIS imaging and immunohistochemistry assay. Our findings suggested that nobiletin might have a great potential for treating glioblastoma.