Hepatitis B virus regulation of Raf1 promoter activity through activation of transcription factor AP-2α

The X protein of hepatitis B virus (HBx) is one of the important factors in the development of hepatocellular carcinoma. Raf1 kinase is a central component of many signaling pathways that are involved in normal cell growth and oncogenic transformation. We previously demonstrated that hepatitis B virus regulates Raf1 expression in HepG2.2.15 cells by enhancing its promoter activity and that HBx and HBs might play an important role in this process. However, the underlying molecular mechanisms remain unclear. In this study, we show that nucleotides ?209 to ?133 of the Raf1 promoter sequence constitute the core region where hepatitis B virus is regulated. This regulation was found to require the involvement of cis-regulatory element AP-2α. We further demonstrated that AP-2α expression was higher in HepG2.2.15 cells (HBV-expressing cells) than in HepG2 cells in vitro. Silencing AP-2α expression by siRNA significantly inhibited the Raf1 promoter activity in HepG2.2.15 cells. These findings indicated that HBV regulates Raf1 promoter activity, possibly through AP-2α.     

Loss of nuclear prothymosin-α expression is associated with disease progression in human superficial bladder cancer

In this paper, we report a study on the clinical relevance of prothymosin-α expression and its correlation with intratumoral Foxp3⁺ and CD8⁺ lymphocytes (Foxp3⁺TIL and CD8⁺TIL) in bladder cancer patients. We used immunohistochemical staining for prothymosin-α, Foxp3, and CD8 on 101 tumor specimens harvested by endoscopic resection. The results were correlated with clinicopathological variables and clinical outcome in bladder cancer patients, particularly in 73 patients with superficial disease, using the log-rank test and Cox proportional hazard model. Overall, of the tumors, 30 % were negative, 34 % showed nuclear, and 37 % showed cytoplasmic prothymosin-α expression. Foxp3⁺TILs were detected in 11 % of patients (nonnuclear vs. nuclear, p?=?0.096). Patients with a history of urothelial carcinoma have a higher frequency of nonnuclear prothymosin-α expression than those without (p?=?0.016, chi-square test). By univariate and multivariate analyses of cases with superficial disease, grade and stage were identified as independent predictors for recurrence-free survival (p?=?0.016 and 0.016, respectively). Higher stage and nonnuclear prothymosin-α expression independently predict shorter progression-free survival (p?=?0.006 and 0.043, respectively). The presence of Foxp3⁺TILs was significantly associated with disease progression by univariate analysis (p?=?0.022), but not by multivariate analysis (p?=?0.147). In vitro assays showed that J82 cells which express ectopically nuclear prothymosin-α exhibit higher growth rate and secrete less TGF-β1 than those with cytoplasmic expression or control cells. Altogether, prothymosin-α expression is a determinant of disease progression in superficial bladder cancer. Foxp3⁺TILs tend to be found more often in bladder cancer with nonnuclear prothymosin-α expression. Future study is required to unravel their interaction.     

Fibroblast growth factor 2 inhibits the expression of stromal cell-derived factor 1α in periodontal ligament cells derived from human permanent teeth in vitro

Although cells derived from periodontal ligament (PDL) tissue are reported to have stem cell-like activity and are speculated to play a crucial role for tissue healing and regeneration after injury or orthodontic treatment, mechanisms regulating their recruitment and activation remain unknown. Recently, stromal cell-derived factor 1α (SDF-1α) has been reported to be important for stem cell homing and recruitment to injured sites. The aim of this study was to evaluate whether fibroblast growth factor 2 (FGF-2) affects the expression of SDF-1α in PDL cells derived from human permanent teeth in vitro. Using real-time PCR, the expression of SDF-1α mRNA in PDL cells was inhibited by treatment with 10 ng/ml FGF-2. When PDL cells were treated with SU5402 (an inhibitor of FGF receptor 1) in combination with FGF-2, the FGF-2-reduced expression of SDF-1α was inhibited. In the presence of the JNK inhibitor SP600125, SDF-1α mRNA in PDL cells was not suppressed by the FGF-2 treatment. Western blot analysis also showed that SDF-1α production was suppressed by treatment with FGF-2, but it recovered with treatment by FGF-2 + SU5402. These findings suggest that SDF-1α from PDL cells plays an important role in the regeneration and homeostasis of periodontal tissues via the recruitment of stem cells.