The prostaglandin H synthases (PGHS) catalyze the conversion of arachidonic acid to prostaglandin H 2 , the committed step in prostanoid synthesis. Two forms of PGHS exist, PGHS-1 (COX-1) and PGHS-2 (COX-2). The gene encoding the latter form is known to be inducible by a number of stimuli including several inflammatory mediators. Recent evidence indicates that the inducible cyclooxygenase may have both pro-and anti-inflammatory properties through the generation of different prostaglandins. Previous reports indicate that the transcription factor NF-B can function upstream of COX-2 to control transcription of this gene and that the cyclopentenone prostaglandins can inhibit NF-B activation via the inhibition of the IB kinase. Thus, it is suggested that cyclopentenones feed back to inhibit continued nuclear accumulation of NF-B. In this report we demonstrate COX-2 expression inhibits nuclear translocation of NF-B, and we confirm that the cyclopentenone prostaglandins inhibit NF-B. In addition, we show that prostaglandin E 2 and its analogs promote the inherent transcriptional activity of the p65/RelA subunit of NF-B in a manner independent of induced nuclear accumulation. Consistent with this evidence, prostaglandin E 2 strongly synergizes with the inflammatory cytokine tumor necrosis factor-␣ to promote NF-Bdependent transcription and gene expression. The data provide a molecular rationale to explain both the proand anti-inflammatory nature of COX-2.

We have recently demonstrated that dendritic cells (DC) prepared from nonobese diabetic (NOD) mice, a spontaneous model for insulin-dependent diabetes mellitus, exhibit elevated levels of NF-κB activation upon stimulation. In the current study, we investigated the influence of dysregulation of NF-κB activation on the APC function of bone marrow-derived DC prepared from NOD vs BALB/c and nonobese diabetes-resistant mice. NOD DC pulsed with either peptide or virus were found to be more efficient than BALB/c DC at stimulating in vitro naive Ag-specific CD8+ T cells. The T cell stimulatory capacity of NOD DC was suppressed by gene transfer of a modified form of IκBα, indicating a direct role for NF-κB in this process. Furthermore, neutralization of IL-12(p70) to block autocrine-mediated activation of DC also significantly reduced the capacity of NOD DC to stimulate T cells. Despite a reduction in low molecular mass polypeptide-2 expression relative to BALB/c DC, no effect on proteasome-dependent events associated with the NF-κB signaling pathway or Ag processing was detected in NOD DC. Finally, DC from nonobese diabetes-resistant mice, a strain genotypically similar to NOD yet disease resistant, resembled BALB/c and not NOD DC in terms of the level of NF-κB activation, secretion of IL-12(p70) and TNF-α, and the capacity to stimulate T cells. Therefore, elevated NF-κB activation and enhanced APC function are specific for the NOD genotype and correlate with the progression of insulin-dependent diabetes mellitus. These results also provide further evidence indicating a key role for NF-κB in regulating the APC function of DC.

Insulin-dependent diabetes mellitus (IDDM) is characterized by the T cell-mediated destruction of insulin-producing β cells. Accordingly, APCs, such as macrophage, have also been shown to be important in the disease process. However, the role(s) of dendritic cells (DCs) that exhibit potent APC function remains undefined in IDDM. Here we demonstrate that DCs derived from nonobese diabetic (NOD) mice, a model for IDDM, are more sensitive to various forms of stimulation compared with those from C57BL/6 and BALB/c mice, resulting in increased IL-12 secretion. This property is a consequence of hyperactivation of NF-κB, a transcription factor known to regulate IL-12 gene expression. Specifically, NOD DCs exhibit persistent hyperactivation of both IκB kinase and NF-κB in response to stimuli, in addition to selective degradation of IκBε. Transfection of NOD DCs with a modified form of IκBα significantly reduced IL-12 secretion, suggesting that hyperactivation of NF-κB was in part responsible for increased IL-12 production. An enhanced capacity of NOD DCs to secrete IL-12 would be expected to contribute to the development of pathogenic Th1 (Tc1) cells during the diabetogenic response.

Background Pruritus can be a distressing and even debilitating symptom for patients with cutaneous T-cell lymphoma (CTCL). To date, few studies have evaluated the pathophysiology of this symptom. Due to this, therapy for pruritus in CTCL has mainly relied on those therapies that target and treat the lymphoma. For patients living with CTCL that relapses or becomes refractory to treatment, and who continue to experience severe itch, this lymphoma-targeted treatment may not be enough to combat their pruritus. Therefore, other itch-targeted therapies are needed for use in this disease Objective Evaluate the current evidence regarding the mechanism of action and treatments for pruritus associated with cutaneous T-cell lymphoma. Methods An explicit and thorough search was restricted to all peer-reviewed literature available through MEDLINE (1950 to September 2011) and pubmed.org. Search terms used were pruritus, cutaneous T-cell lymphoma (CTCL), mycosis fungoides (MF), and Sézary Syndrome (SS). All studies that involved pruritus in either CTCL, MF, or SS were evaluated by all three authors. Results The current literature helps to identify therapies and possible mechanisms for treating patients with CTCL associated pruritus. . Limitation Most studies were pre-clinical. Only studies involving mechanisms of action or treatment were included Conclusion A guideline is necessary to assist in the treatment of pruritus in CTCL and additional studies are necessary to uncover the exact mechanism(s) of action.

Type 1 diabetes is characterized by a chronic inflammatory response resulting in the selective destruction of the insulin-producing β cells. We have previously demonstrated that dendritic cells (DCs) prepared from nonobese diabetic (NOD) mice, a model for spontaneous type 1 diabetes, exhibit hyperactivation of NF-κB resulting in an increased capacity to secrete proinflammatory cytokines and stimulate T cells compared with DCs of nondiabetic strains of mice. In the current study, the activational status of NF-κB and its role in regulating the APC function of macrophages (Mφ) prepared from NOD, nonobese resistant (NOR), and BALB/c mice was investigated. Independent of the stimulus, splenic and bone marrow-derived Mφ prepared from NOD mice exhibited increased NF-κB activation relative to NOR and BALB/c Mφ. This hyperactivation was detected for different NF-κB complexes and correlated with increased IκBα degradation. Furthermore, increased NF-κB activation resulted in an enhanced capacity of NOD vs NOR or BALB/c Mφ to secrete IL-12(p70), TNF-α, and IL-1α, which was inhibited upon infection with an adenoviral recombinant encoding a modified form of IκBα. In contrast, elevated NF-κB activation had no significant effect on the capacity of NOD Mφ to stimulate CD4+ or CD8+ T cells in an Ag-specific manner. These results demonstrate that in addition to NOD DCs, NOD Mφ exhibit hyperactivation of NF-κB, which correlates with an increased ability to mediate a proinflammatory response. Furthermore, NF-κB influences Mφ APC function by regulating cytokine secretion but not T cell stimulation.

In searching for small-molecule compounds that inhibit proliferation and survival of diffuse large B-cell lymphoma (DLBCL) cells and may, therefore, be exploited as potential therapeutic agents for this disease, we identified the commonly used and well-tolerated antibiotic doxycycline as a strong candidate. Here, we demonstrate that doxycycline inhibits the growth of DLBCL cells both in vitro and in mouse xenograft models. In addition, we show that doxycycline accumulates in DLBCL cells to high concentrations and affects multiple signaling pathways that are crucial for lymphomagenesis. Our data reveal the deneddylating activity of COP-9 signalosome (CSN) as a novel target of doxycycline and suggest that doxycycline may exert its effects in DLBCL cells in part through a CSN5-HSP90 pathway. Consistently, knockdown of CSN5 exhibited similar effects as doxycycline treatment on DLBCL cell survival and HSP90 chaperone function. In addition to DLBCL cells, doxycycline inhibited growth of several other types of non-Hodgkin lymphoma cells in vitro. Together, our results suggest that doxycycline may represent a promising therapeutic agent for DLBCL and other non-Hodgkin lymphomas subtypes.

Cutaneous T-cell Lymphoma (CTCL) is a rare non-Hodgkin's lymphoma that can affect the skin, blood, and lymph nodes, and can metastasize at late stages. Novel therapies that target all affected disease compartments and provide longer lasting responses while being safe are needed. One potential therapeutic target is NF-λB, a regulator of immune responses and an important participant in carcinogenesis and cancer progression. As a transcription factor, NF-λB targets genes that promote cell proliferation and survival. Constitutive or aberrant activation of NF-λB is encountered in many types of cancer, including CTCL.Recently, while analyzing gene-expression profiles of a variety of small molecule compounds that target NF-λB, we discovered the tetracycline family of antibiotics, including doxycycline, to be potent inhibitors of the NF-λB pathway. Doxycycline is well-tolerated, safe, and inexpensive; and is commonly used as an antibiotic and anti-inflammatory for the treatment a multitude of medical conditions.In our current study, we show that doxycycline induces apoptosis in a dose dependent manner in multiple different cell lines from patients with the two most common subtypes of CTCL, Mycosis Fungoides (MF) and Sézary Syndrome (SS). Similar results were found using primary CD4+ T cells from a patient with SS. Doxycycline inhibits TNF induced NF-λB activation and reduces expression of NF-λB dependent anti-apoptotic proteins, such as BCL2α. Furthermore, we have identified that doxycycline induces apoptosis through reactive oxygen species.

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