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Background: The pathogenesis of several neurodegenerative diseases often involves the microglial activation and associated inflammatory processes. Activated microglia release pro-inflammatory factors that may be neurotoxic. 6-Mercaptopurine (6-MP) is a well-established immunosuppressive drug. Common understanding of their immunosuppressive properties is largely limited to peripheral immune cells. However, the effect of 6-MP in the central nervous system, especially in microglia in the context of neuroinflammation is, as yet, unclear. Tumor necrosis factor-α (TNF-α) is a key cytokine of the immune system that initiates and promotes neuroinflammation. The present study aimed to investigate the effect of 6-MP on TNF-α production by microglia to discern the molecular mechanisms of this modulation.Methods: Lipopolysaccharide (LPS) was used to induce an inflammatory response in cultured primary microglia or murine BV-2 microglial cells. Released TNF-α was measured by enzyme-linked immunosorbent assay (ELISA). Gene expression was determined by real-time reverse transcription polymerase chain reaction (RT-PCR). Signaling molecules were analyzed by western blotting, and activation of NF-κB was measured by ELISA-based DNA binding analysis and luciferase reporter assay. Chromatin immunoprecipitation (ChIP) analysis was performed to examine NF-κB p65 and coactivator p300 enrichments and histone modifications at the endogenous TNF-α promoter.Results: Treatment of LPS-activated microglia with 6-MP significantly attenuated TNF-α production. In 6-MP pretreated microglia, LPS-induced MAPK signaling, IκB-α degradation, NF-κB p65 nuclear translocation, and in vitro p65 DNA binding activity were not impaired. However, 6-MP suppressed transactivation activity of NF-κB and TNF-α promoter by inhibiting phosphorylation and acetylation of p65 on Ser276 and Lys310, respectively. ChIP analyses revealed that 6-MP dampened LPS-induced histone H3 acetylation of chromatin surrounding the TNF-α promoter, ultimately leading to a decrease in p65/coactivator-mediated transcription of TNF-α gene. Furthermore, 6-MP enhanced orphan nuclear receptor Nur77 expression. Using RNA interference approach, we further demonstrated that Nur77 upregulation contribute to 6-MP-mediated inhibitory effect on TNF-α production. Additionally, 6-MP also impeded TNF-α mRNA translation through prevention of LPS-activated PI3K/Akt/mTOR signaling cascades.Conclusions: These results suggest that 6-MP might have a therapeutic potential in neuroinflammation-related neurodegenerative disorders through downregulation of microglia-mediated inflammatory processes. [ABSTRACT FROM AUTHOR]

Background Epidemiological evidence of relationships between endometriosis and epithelial ovarian cancer (EOC) has been obtained mainly from Western countries. Our goal was to determine the risk of EOC due to endometriosis in Taiwanese women. Methods A retrospective cohort study was performed by linking to the National Health Insurance Research Database (NHIRD) of Taiwan. A total of 5,945 women with a new surgico- pathological diagnosis of endometriosis from 2000 to 2010 and 23,780 multivariable- matched controls (1:4) were selected. The Cox regression model adjusted for potential confounders was used to assess the risk of EOC due to endometriosis. Results The EOC incidence rate (IR) of the women with and without endometriosis was 11.64 and 2.66 per 10,000 person-years, contributing to a crude hazard ratio (HR) of 4.48 (95% confidence interval [CI] 2.84-7.06), and HR after adjustment for all confounders (adjusted HR) of 5.62 (95% CI 3.46-9.14); the risk was higher in clear-cell carcinoma subtypes (adjusted HR 7.36, 95% CI 1.91-28.33). The EOC IR of women with endometriosis consistently increased with increasing age, ranging from 4.99 (<30 years) to 35.81 (≥50 years) per 10,000 person-years, contributing to a progressively increased risk of EOC (crude HRs ranging from 2.80 to 6.74 and adjusted HRs ranging from 3.34 to 9.63) compared to age-matched women without endometriosis, whose EOC IR also increased with age. The older women (≥50 years) with endometriosis had a risk of EOC that was higher than both the age-matched women without endometriosis (adjusted HR 9.63, 95% CI 3.27-28.37) and the youngest women (<30 years) with endometriosis (adjusted HR 4.97, 95% CI 1.03-24.09). Conclusions These significant findings corroborate the previously reported association between endometriosis and increased risk of EOC. Since the risk of EOC in women with a new surgico-pathological diagnosis of endometriosis constantly increased with age and this increased risk of EOC was more significant in women aged ≥50 years, active and intensive surgical intervention should be taken into consideration for older women with endometriosis. [ABSTRACT FROM AUTHOR]

Background Overexpression of heterogeneous nuclear ribonucleoprotein K (hnRNP K), a DNA/RNA binding protein, is associated with metastasis in nasopharyngeal carcinoma (NPC). However, the mechanisms underlying hnRNP K-mediated metastasis is unclear. The aim of the present study was to determine the role of matrix metalloproteinase (MMP) in hnRNP K-mediated metastasis in NPC. Methods We studied hnRNP K-regulated MMPs by analyzing the expression profiles of MMP family genes in NPC tissues and hnRNP K-knockdown NPC cells using Affymetrix microarray analysis and quantitative RT-PCR. The association of hnRNP K and MMP12 expression in 82 clinically proven NPC cases was determined by immunohistochemical analysis. The hnRNP K-mediated MMP12 regulation was determined by zymography and Western blot, as well as by promoter, DNA pull-down and chromatin immunoprecipitation (ChIP) assays. The functional role of MMP12 in cell migration and invasion was demonstrated by MMP12-knockdown and the treatment of MMP12-specific inhibitor, PF-356231. Results MMP12 was overexpressed in NPC tissues, and this high level of expression was significantly correlated with high-level expression of hnRNP K (P = 0.026). The levels of mRNA, protein and enzyme activity of MMP12 were reduced in hnRNP K-knockdown NPC cells. HnRNP K interacting with the region spanning -42 to -33 bp of the transcription start site triggered transcriptional activation of the MMP12 promoter. Furthermore, inhibiting MMP12 by MMP12 knockdown and MMP12-specific inhibitor, PF-356231, significantly reduced the migration and invasion of NPC cells. Conclusions Overexpression of MMP12 was significantly correlated with hnRNP K in NPC tissues. HnRNP K can induce MMP12 expression and enzyme activity through activating MMP12 promoter, which promotes cell migration and invasion in NPC cells. In vitro experiments suggest that NPC metastasis with high MMP12 expression may be treated with PF-356231. HnRNP K and MMP12 may be potential therapeutic markers for NPC, but additional validation studies are warranted. [ABSTRACT FROM AUTHOR]