Immune function abnormalities in peripheral blood mononuclear cell cytokine expression differentiates stages of cutaneous T-cell lymphoma/mycosis fungoides.

PURPOSE: Mycosis fungoides (MF) is a cutaneous T-cell lymphoma (CTCL) characterized by neoplastic skin-homing T cells. To better understand the immunopathogenesis of MF, we analyzed the functional ability of peripheral blood mononuclear cells (PBMC) from early and late MF/CTCL patients to express cytokine genes. In late stage MF/CTCL, patients were separated into those with blood involvement (+B) and without blood involvement (-B). EXPERIMENTAL DESIGN: We analyzed T(H)1 (interleukin 2 (IL-2), IFN-gamma), T(H)2 (IL-4, IL-5, IL-10, IL-13), and T(H)17 (IL-17) cytokine gene expression from activated PBMCs from normal (n = 12), psoriasis (n = 6), early MF/CTCL (n = 11), and late MF/CTCL+B (n = 4) and MF/CTCL-B (n = 3) by quantitative real-time PCR. RESULTS: PBMCs from early MF/CTCL and psoriasis showed higher induction of IL-2, IL-4, and IFN-gamma genes than those from normal and late MF/CTCL-B and MF/CTCL+B (P < 0.05) in descending order. PBMCs from late MF/CTCL-B exhibited generally the highest level of IL-5, IL-10, IL-13, and IL-17 expression compared with the other groups. PBMCs from early MF/CTCL and late MF/CTCL-B had similarly elevated IL-13 and IL-17. Of all groups, PBMCs from late MF/CTCL+B had the lowest levels of IL-2 (P < 0.05), IL-4, IFN-gamma, IL-13, and IL-17. CONCLUSIONS: The different pattern of cytokine gene expression suggests a change in immune function in MF/CTCL from early MF/CTCL to late MF/CTCL-B to late MF/CTCL+B. These stages are consistent with localized disease associated with an anti-tumor immune response and late MF/CTCL associated with a loss of immune function mediated by malignant T cells that share regulatory T cell-like properties.

Induction of the CTLA-4 gene in human lymphocytes is dependent on NFAT binding the proximal promoter.

CTLA-4 is a member of the costimulatory family, has homology to CD28, and binds the B7 family of ligands. Unlike CD28, CTLA-4 ligation transmits a negative signal in T cells. CTLA-4 expression, while inducible in most T cells, is expressed constitutively on T cells with a regulatory phenotype. The mechanism controlling CTLA-4 expression in human T cells is poorly characterized, thus we sought to better understand the mechanism of activation of the CTLA-4 gene. By cloning the 5' upstream promoter and creating promoter-deletion reporter constructs, we show that the proximal promoter is critical for activating the CTLA-4 gene. Within this region, we identify a NFAT consensus sequence that binds NFAT with high affinity that differs from other NFAT sequences and does not recruit AP-1. Analysis of the chromatin proteins in the native CTLA-4 gene shows that this promoter region becomes associated with acetylated histones by chromatin immunoprecipitation assays. In addition, NFAT1 binds to the promoter of the CTLA-4 gene after stimulation by chromatin immunoprecipitation. The functional requirement of the NFAT site for CTLA-4 transcription was demonstrated by mutations in the NFAT site that abolished the activity of the promoter. Furthermore, inhibitors of NFAT suppressed CTLA-4 gene expression, indicating that NFAT plays a critical role in regulating the induction of the CTLA-4 gene in lymphocytes. The identification of NFAT as a critical regulator of the CTLA-4 gene suggests that targeting NFAT function may lead to novel approaches to modulate the CTLA-4 gene to control the immune response.

Increased expression of CTLA-4 in malignant T-cells from patients with mycosis fungoides -- cutaneous T cell lymphoma.

Mycosis fungoides (MF) is a low-grade lymphoma of cluster of differentiation (CD)4+, CD45RO+, cutaneous leukocyte antigen (CLA)+ T cells that homes to the skin. To understand the functional abnormalities in this disease, we study the regulation of cytotoxic T-lymphocyte antigen (CTLA)-4 in peripheral blood mononuclear cells (PBMCs) from patients with MF. CTLA-4 is a costimulatory molecule for T cells that functions in immunoregulation. Unlike the expression of CD28, which is expressed constitutively on T cells, CTLA-4 expression is highly regulated. In the analysis of PBMCs in MF, we found that CTLA-4 is stimulated by phorbol myristate acetate/A23187 to a greater level when compared to normals. This defect was seen in the dominant clones of T cells. The increased CTLA-4 expression was significant between normal and MF, with a correlation between higher expression of CTLA-4 and a higher grade of MF. In a patient whose disease progressed, the CTLA-4 level increased. The abnormal level of CTLA-4 was confirmed at both the transcription and translation levels. Although MF is associated with a Th2 bias, Th1 cytokines IL-2 and IFN-gamma enhanced CTLA-4 expression, while IL-4 did not. These findings reveal an abnormal regulation of CTLA-4 expression in MF and show that PBMCs from patients with MF have properties that are divergent from those of normal T cells.

Curcumin sensitizes prostate cancer cells to tumor necrosis factor-related apoptosis-inducing ligand/Apo2L by inhibiting nuclear factor-kappaB through suppression of IkappaBalpha phosphorylation.

Epidemiologic studies suggest that diet rich in plant-derived foods plays an important role in the prevention of prostate cancer. Curcumin, the yellow pigment in the spice turmeric, has been shown to exhibit chemopreventive and growth inhibitory activities against multiple tumor cell lines. We have shown previously that curcumin and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)/Apo2L interact to induce cytotoxicity in the LNCaP prostate cancer cell line. In this study, we investigated the mechanism by which curcumin augments TRAIL-induced cytotoxicity in LNCaP cells. Subtoxic concentrations of the curcumin-TRAIL combination induced strong apoptotic response in LNCaP cells as demonstrated by the binding of Annexin V-FITC and cleavage of procaspase-3. Furthermore, LNCaP cells express constitutively active nuclear factor-kappaB (NF-kappaB), which is inhibited by curcumin. Because NF-kappaB has been shown to mediate resistance to TRAIL-induced apoptosis in tumor cells, we investigated whether there is a relationship between NF-kappaB activation and resistance to TRAIL in LNCaP prostate cancer cells. Pretreatment with curcumin inhibited the activation of NF-kappaB and sensitized LNCaP cells to TRAIL. A similar increase in the sensitivity of LNCaP cells to TRAIL-induced apoptosis was observed following inhibition of NF-kappaB by dominant negative mutant IkappaBalpha, an inhibitor of NF-kappaB. Finally, curcumin was found to inhibit NF-kappaB by blocking phosphorylation of IkappaBalpha. We conclude that NF-kappaB mediates resistance of LNCaP cells to TRAIL and that curcumin enhances the sensitivity of these tumor cells to TRAIL by inhibiting NF-kappaB activation by blocking phosphorylation of IkappaBalpha and its degradation.

Erythropoietin up-regulates SOCS2 in neuronal progenitor cells derived from SVZ of adult rat.

We examined the effects of EPO on expression of suppressor of cytokine signaling 2 (SOCS2) and found that treatment of neural progenitor cells derived from the adult subventricular zone (SVZ) with recombinant human EPO (rhEPO) stimulated progenitor cell differentiation into neurons, but not astrocytes. Quantitative RT-PCR revealed that SOCS2 mRNA levels were increased in the progenitor cells treated with rhEPO. Immunostaining showed that neurons but not astrocytes were SOCS2 immunoreactive. Incubation of the progenitor cells with rhEPO in the presence of a neutralizing antibody against EPO abolished the effects of EPO on neuronal differentiation and expression of SOCS2. Our data suggest that up-regulation of SOCS2 in neuronal progenitor cells derived from the adult SVZ may regulate EPO enhanced neuronal differentiation.

Insulin signaling in the transcriptional and posttranscriptional regulation of CYP2E1 expression.

Diabetes has been reported to increase the expression of cytochrome P450 (CYP) 2E1 messenger RNA (mRNA) and protein several-fold, and enhanced expression has been associated with elevated ketone bodies. Primary cultured rat hepatocytes were used to explore ketone body and insulin regulation of CYP2E1 expression. Hydroxybutyrate and acetoacetate (AC), alone or in combination, either failed to affect or decreased CYP2E1 mRNA levels by up to 90% relative to untreated hepatocytes. Insulin produced a concentration-dependent decrease in CYP2E1 mRNA levels, and insulin receptor immunoprecipitation showed a correspondence between receptor phosphorylation and the decrease in CYP2E1 mRNA levels at physiologic levels of insulin. Phosphatase inhibitors decreased CYP2E1 mRNA levels by greater than 95%. The phosphatidylinositol 3-kinase (PI3-kinase) inhibitors wortmannin or LY294002 and rapamycin, an inhibitor of p70 S6 kinase phosphorylation, ameliorated the insulin-mediated decrease in CYP2E1 mRNA levels. Geldanamycin, which inhibits Src kinase, also abrogated the insulin-mediated decrease in CYP2E1 mRNA levels. In contrast, the protein kinase C (PKC) inhibitor bisindolylmaleimide, the mitogen-activated protein kinase kinase (MEK) inhibitor PD98059, and the p38 mitogen-activated protein (MAP) kinase inhibitor SB202190 did not affect the insulin-mediated decrease in CYP2E1. CYP2E1 mRNA half-life decreased from approximately 48 hours in the absence of insulin to approximately 15 hours at 10 nmol/L insulin, and this decrease was prevented by wortmannin. The half-life of CYP2B mRNA was increased by insulin, whereas that of CYP3A was unaffected. Analysis of CYP2E1 gene transcription using heterogeneous nuclear RNA (hnRNA) showed that insulin suppressed CYP2E1 transcription. In conclusion, these data show involvement of transcriptional and posttranscriptional mechanisms in the insulin-mediated regulation of CYP2E1 and implicate PI3-kinase, p70 S6 kinase, and Src kinase in mediating these effects.