Roles of OX40 and OX40 Ligand in Mycosis Fungoides and Sézary Syndrome.

Mycosis fungoides (MF) and Sézary syndrome (SS), the most common types of cutaneous T-cell lymphoma (CTCL), are characterized by proliferation of mature CD4+ T-helper cells. Patients with advanced-stage MF and SS have poor prognosis, with 5-year survival rates of 52%. Although a variety of systemic therapies are currently available, there are no curative options for such patients except for stem cell transplantation, and thus the treatment of advanced MF and SS still remains challenging. Therefore, elucidation of the pathophysiology of MF/SS and development of medical treatments are desired. In this study, we focused on a molecule called OX40. We examined OX40 and OX40L expression and function using clinical samples of MF and SS and CTCL cell lines. OX40 and OX40L were co-expressed on tumor cells of MF and SS. OX40 and OX40L expression was increased and correlated with disease severity markers in MF/SS patients. Anti-OX40 antibody and anti-OX40L antibody suppressed the proliferation of CTCL cell lines both in vitro and in vivo. These results suggest that OX40-OX40L interactions could contribute to the proliferation of MF/SS tumor cells and that the disruption of OX40-OX40L interactions could become a new therapeutic strategy for the treatment of MF/SS.

Synergistic effect of glucocorticoids and IGF-1 on myogenic differentiation through the Akt/GSK-3ß pathway in C2C12 myoblasts.

Purpose: Glucocorticoids are the only therapeutics that can delay the progression of Duchenne musculardystrophy (DMD), the most prevalent type of inherited neuromuscular disorder in males. However, beyond theiranti-inflammatory effects, glucocorticoids have other underlying mechanisms that remain unclear. Moreover, muscleand circulating levels of insulin growth factor-1 (IGF-1) often decrease in response to glucocorticoids. Therefore, wehypothesized that glucocorticoids, either alone or in combination with IGF-1, can improve myogenic differentiation.Materials and methods: Established C2C12 myoblasts were employed as an in vitro model of myogenic differentiation,and myogenic differentiation markers, as assessed by Western blot (myogenin, MyoD, and MyHC protein expression),cellular morphology analysis (fusion index) and RT-PCR (MCK mRNA expression), were measured.Results: Myogenic differentiation markers were increased by glucocorticoid treatment. Furthermore, this effect was furtherenhanced by IGF-1, and these results suggest that glucocorticoids, either alone or together with IGF-1, can promotemyogenic differentiation. Akt and GSK-3ß play important roles in myogenic differentiation. Interestingly, the levels ofboth phosphorylated Ser473-Akt and phosphorylated Ser9-GSK-3ß were increased by glucocorticoid and IGF-1 cotreatment.Pharmacological manipulation with LY294002 and LiCl was employed to inhibit Akt and GSK-3ß, respectively.We found that cellular differentiability was inhibited by LY294002 and enhanced by LiCl, indicating that theAkt/GSK-3ß signaling pathway is activated by glucocorticoid and IGF-1 treatment to promote myogenic differentiation.Conclusions: Glucocorticoids together with IGF-1 promote myogenic differentiation through the Akt/GSK-3ßpathway. Thus, these results further our knowledge of myogenic differentiation and may offer a potential alternativestrategy for DMD treatment based on glucocorticoid and IGF-1.

Ubiquitin-specific protease 8 inhibitor suppresses adrenocorticotropic hormone production and corticotroph tumor cell proliferation.

Cushing's disease is primarily caused by autonomic hypersecretion of adrenocorticotropic hormone (ACTH) from a pituitary adenoma. In Cushing's disease, mutations in the ubiquitin-specific protease 8 (USP8) have been detected. These mutations are associated with hyperactivation of USP8 that prevent epidermal growth factor receptor (EGFR) degradation. This leads to increased EGFR stability and results in the maintenance of EGFR signaling in Cushing's disease. USP8 inhibitors can suppress the growth of various tumors. In this study, the effects of a potent USP8 inhibitor, DUBs-IN-2, on ACTH production and cell proliferation were examined in mouse corticotroph tumor (AtT-20) cells. Proopiomelanocortin (Pomc) mRNA levels and ACTH levels were decreased in AtT-20 cells by DUBs-IN-2. Further, cell proliferation was inhibited, and apoptosis was induced by DUBs-IN-2. Transcript levels of pituitary tumor-transforming gene 1 (Pttg1), a pituitary tumor growth marker, were increased; and transcript levels of stress response growth arrest and DNA damage-inducible 45 (Gadd45ß) and Cdk5 and ABL enzyme substrate 1 (Cables1) mRNA levels were increased in response to the drug. Gadd45ß or Cables1 knockdown partially inhibited the DUBs-IN-2-induced decrease in cell proliferation, but not Pomc mRNA levels. Both GADD45ß and CABLES1 may be responsible, at least in part, for the USP8-induced suppression of corticotroph tumor cell proliferation. USP-8 may be a new treatment target in Cushing's disease.

Krüppel-Like Factor 15 Mediates Glucocorticoid-Induced Restoration of Podocyte Differentiation Markers.

Podocyte injury is the inciting event in primary glomerulopathies, such as minimal change disease and primary FSGS, and glucocorticoids remain the initial and often, the primary treatment of choice for these glomerulopathies. Because inflammation is not readily apparent in these diseases, understanding the direct effects of glucocorticoids on the podocyte, independent of the immunomodulatory effects, may lead to the identification of targets downstream of glucocorticoids that minimize toxicity without compromising efficacy. Several studies showed that treatment with glucocorticoids restores podocyte differentiation markers and normal ultrastructure and improves cell survival in murine podocytes. We previously determined that Krüppel-like factor 15 (KLF15), a kidney-enriched zinc finger transcription factor, is required for restoring podocyte differentiation markers in mice and human podocytes under cell stress. Here, we show that in vitro treatment with dexamethasone induced a rapid increase of KLF15 expression in human and murine podocytes and enhanced the affinity of glucocorticoid receptor binding to the promoter region of KLF15 In three independent proteinuric murine models, podocyte-specific loss of Klf15 abrogated dexamethasone-induced podocyte recovery. Furthermore, knockdown of KLF15 reduced cell survival and destabilized the actin cytoskeleton in differentiated human podocytes. Conversely, overexpression of KLF15 stabilized the actin cytoskeleton under cell stress in human podocytes. Finally, the level of KLF15 expression in the podocytes and glomeruli from human biopsy specimens correlated with glucocorticoid responsiveness in 35 patients with minimal change disease or primary FSGS. Thus, these studies identify the critical role of KLF15 in mediating the salutary effects of glucocorticoids in the podocyte.

Lifelong quercetin enrichment and cardioprotection in Mdx/Utrn+/- mice.

Duchenne Muscular Dystrophy (DMD) is associated with progressive cardiac pathology; however, the SIRT1/PGC1-α activator quercetin may cardioprotect dystrophic hearts. We tested the extent to which long-term 0.2% dietary quercetin enrichment attenuates dystrophic cardiopathology in Mdx/Utrn+/- mice. At 2 mo, Mdx/Utrn+/- mice were fed quercetin-enriched (Mdx/Utrn+/--Q) or control diet (Mdx/Utrn+/-) for 8 mo. Control C57BL/10 (C57) animals were fed a control diet for 10 mo. Cardiac function was quantified by MRI at 2 and 10 mo. Spontaneous physical activity was quantified during the last week of treatment. At 10 mo hearts were excised for histological and biochemical analysis. Quercetin feeding improved various physiological indexes of cardiac function in diseased animals. Mdx/Utrn+/--Q also engaged in more high-intensity physical activity than controls. Histological analyses of heart tissues revealed higher expression and colocalization of utrophin and α-sarcoglycan. Lower abundance of fibronectin, cardiac damage (Hematoxylin Eosin-Y), and MMP9 were observed in quercetin-fed vs. control Mdx/Utrn+/- mice. Quercetin evoked higher protein abundance of PGC-1α, cytochrome c, ETC complexes I-V, citrate synthase, SOD2, and GPX compared with control-fed Mdx/Utrn+/- Quercetin decreased abundance of inflammatory markers including NFκB, TGF-ß1, and F4/80 compared with Mdx/Utrn+/-; however, P-NFκB, P-IKBα, IKBα, CD64, and COX2 were similar between groups. Dietary quercetin enrichment improves cardiac function in aged Mdx/Utrn+/- mice and increases mitochondrial protein content and dystrophin glycoprotein complex formation. Histological analyses indicate a marked attenuation in pathological cardiac remodeling and indicate that long-term quercetin consumption benefits the dystrophic heart. NEW & NOTEWORTHY: The current investigation provides first-time evidence that quercetin provides physiological cardioprotection against dystrophic pathology and is associated with improved spontaneous physical activity. Secondary findings suggest that quercetin-dependent outcomes are in part due to PGC-1α pathway activation.

Cell death caused by the synergistic effects of zinc and dopamine is mediated by a stress sensor gene Gadd45b - implication in the pathogenesis of Parkinson's disease.

The pathogenesis of Parkinson's disease (PD) is not completely understood, Zinc (Zn(2+) ) and dopamine (DA) have been shown to involve in the degeneration of dopaminergic cells. By microarray analysis, we identified Gadd45b as a candidate molecule that mediates Zn(2+) and DA-induced cell death; the mRNA and protein levels of Gadd45b are increased by Zn(2+) treatment and raised to an even higher level by Zn(2+) plus DA treatment. Zn(2+) plus DA treatment-induced PC12 cell death was enhanced when there was over-expression of Gadd45b and was decreased by knock down of Gadd45b. MAPK p38 and JNK signaling was able to cross-talk with Gadd45b during Zn(2+) and DA treatment. The synergistic effects of Zn(2+) and DA on PC12 cell death can be accounted for by an activation of the Gadd45b-induced cell death pathway and an inhibition of p38/JNK survival pathway. Furthermore, the in vivo results show that the levels of Gadd45b protein expression and phosphorylation of p38 were increased in the substantia nigra by the infusion of Zn(2+) /DA in the mouse brain and the level of Gadd45b mRNA is significantly higher in the substantia nigra of male PD patients than normal controls. The novel role of Gadd45b and its interactions with JNK and p38 will help our understanding of the pathogenesis of PD and help the development of future treatments for PD. Zinc and dopamine are implicated in the degeneration of dopaminergic neurons. We previously demonstrated that zinc and dopamine induced synergistic effects on PC12 cell death. Results from this study show that these synergistic effects can be accounted for by activation of the Gadd45b-induced cell death pathway and inhibition of the p38/JNK survival pathway. We provide in vitro and in vivo evidence to support a novel role for Gadd45b in the pathogenesis of Parkinson's disease.

Molecular mechanisms and timing of cortical immune activation in schizophrenia.

OBJECTIVE: Immune-related abnormalities are commonly reported in schizophrenia, including higher mRNA levels for the viral restriction factor interferon-induced transmembrane protein (IFITM) in the prefrontal cortex. The authors sought to clarify whether higher IFITM mRNA levels and other immune-related disturbances in the prefrontal cortex are the consequence of an ongoing molecular cascade contributing to immune activation or the reflection of a long-lasting maladaptive response to an in utero immune-related insult. METHOD: Quantitative polymerase chain reaction was employed to measure mRNA levels for immune-related cytokines and transcriptional regulators, including those reported to regulate IFITM expression, in the prefrontal cortex from 62 schizophrenia and 62 healthy subjects and from adult mice exposed prenatally to maternal immune activation or in adulthood to the immune stimulant poly(I:C). RESULTS: Schizophrenia subjects had markedly higher mRNA levels for interleukin 6 (IL-6) (+379%) and interferon-ß (+29%), which induce IFITM expression; lower mRNA levels for Schnurri-2 (-10%), a transcriptional inhibitor that lowers IFITM expression; and higher mRNA levels for nuclear factor-κB (+86%), a critical transcription factor that mediates cytokine regulation of immune-related gene expression. In adult mice that received daily poly(I:C) injections, but not in offspring with prenatal exposure to maternal immune activation, frontal cortex mRNA levels were also markedly elevated for IFITM (+304%), multiple cytokines including IL-6 (+493%), and nuclear factor-κB (+151%). CONCLUSIONS: These data suggest that higher prefrontal cortex IFITM mRNA levels in schizophrenia may be attributable to adult, but not prenatal, activation of multiple immune markers and encourage further investigation into the potential role of these and other immune markers as therapeutic targets in schizophrenia.

The antimicrobial protein S100A7/psoriasin enhances the expression of keratinocyte differentiation markers and strengthens the skin's tight junction barrier.

BACKGROUND: S100A7/psoriasin is a member of the S100 protein family and is encoded in the epidermal differentiation complex, which contains genes for markers of epidermal differentiation. S100A7/psoriasin is overexpressed in hyperproliferative skin diseases, where it is believed not only to exhibit antimicrobial functions, but also to induce immunomodulatory activities, including chemotaxis and cytokine/chemokine production. OBJECTIVES: To evaluate the effect of S100A7/psoriasin on keratinocyte differentiation and regulation of the tight junction (TJ) barrier. METHODS: Expression of differentiation markers and TJ proteins in human keratinocytes was determined by real-time polymerase chain reaction and Western blot. The changes in TJ barrier function were assessed by transepithelial electrical resistance and paracellular permeability assays. Glycogen synthase kinase-3 (GSK-3) and mitogen-activated protein kinase (MAPK) activation was analysed by Western blot, whereas ß-catenin and E-cadherin activation was evaluated by Western blot and immunofluorescence. RESULTS: S100A7/psoriasin enhanced the expression of several differentiation markers and selectively increased the expression of TJ proteins (e.g. claudins and occludin), which are known to strengthen the TJ barrier. Furthermore, S100A7/psoriasin increased ß-catenin and E-cadherin accumulation at cell-cell contact, and enhanced transepithelial electrical resistance while reducing the paracellular permeability of keratinocyte layers. The data suggest that S100A7/psoriasin-mediated regulation of the TJ barrier was via both the GSK-3 and MAPK pathways, as evidenced by the inhibitory effects of inhibitors for GSK-3 and MAPKs. CONCLUSIONS: Our finding that S100A7/psoriasin regulates differentiation and strengthens TJ barrier function provides novel evidence that, in addition to antimicrobial and immunoregulatory activities, S100A7/psoriasin is involved in skin innate immunity.

Signal regulatory protein α is associated with tumor-polarized macrophages phenotype switch and plays a pivotal role in tumor progression.

UNLABELLED: Macrophages (Mψ) are the major component of infiltrating leukocytes in tumors and exhibit distinct phenotypes according to the microenvironment. We have recently found that signal regulatory protein α (SIRPα), the inhibitory molecule expressed on myeloid cells, plays a critical role in controlling innate immune activation. Here, we identify that SIRPα is down-regulated on monocytes/Mψ isolated from peritumoral areas of hepatocellular carcinoma (HCC) samples, while its level is moderately recovered in intratumor Mψ. In vitro assays demonstrate that SIRPα expression is significantly reduced on Mψ when cocultured with hepatoma cells. This reduction is partly due to the soluble factors in the tumor microenvironment. Knockdown (KD) of SIRPα prolongs activation of nuclear factor kappa B (NF-κB) and PI3K-Akt pathways as Mψ encounter tumor cells, leading to an increased capacity of Mψ for migration, survival, and proinflammatory cytokine production. Enhanced Stat3 and impaired Stat1 phosphorylation are also observed in tumor-exposed SIRPα-KD Mψ. Adoptive transfer with SIRPα-KD Mψ accelerates mouse hepatoma cells growth in vivo by remolding the inflammatory microenvironment and promoting angiogenesis. SIRPα accomplishes this partly through its sequestration of the signal transducer Src homology 2-containing phosphotyrosine phosphatase (SHP2) from IκB kinase ß (IKKß) and PI3K regulatory subunit p85 (PI3Kp85). CONCLUSION: These findings suggest that SIRPα functions as an important modulator of tumor-polarized Mψ in hepatoma, and the reduction of SIRPα is a novel strategy used by tumor cells to benefit their behavior. Therefore, SIRPα could be utilized as a potential target for HCC therapy.

Beta-lapachone suppresses radiation-induced activation of nuclear factor-kappaB.

Anticancer effects of beta-lapachone (beta-lap) are due to generation of ROS and metabolic catastrophes as a result of NAD(P)H:quinone oxidoreductase (NQO1)-mediated futile cycling between the oxidized and reduced forms of beta-lap. It has been shown that NQO1 is also essential for the TNF-induced activation of NF-kappaB and that beta-lap suppresses the TNF-induced NF-kappaB activation. We investigated whether or not NQO1 is involved and beta-lap suppresses the radiation-induced NF-kappaB activation using A549 human lung cancer cells and NQO1-knock down A549 cells (shNQO1 A549 cells). Irradiation with 4 Gy markedly increased the DNA binding activity of NF-kappaB in A549 cells, but not in the shNQO1 A549 cells, thus demonstrating that NQO1 plays a pivotal role in irradiation-induced NF-kappaB activation. Treatment with 10 micronM beta-lap for 4 h almost completely abrogated the radiation-induced increase in NF-kappaB activation and the transcription of NF-kappaB target genes such as bcl2, gadd45beta and cyclinD1. Moreover, beta-lap markedly suppressed the activation of IkappaB kinase gamma (IKKgamma) and the subsequent phosphorylation of IkappaBalpha, thereby inhibiting NF-kappaB activation. It is concluded that beta-lap suppresses the radiation-induced activation of NF-kappaB by interrupting the involvement of NQO1 in the activation of NF-kappaB, thereby inhibiting the transcription of survival signals. The radiosensitization caused by beta-lap may, in part, be attributed to beta-lap-induced suppression of NF-kappaB activation.

Prognostic factors related to clinical response in patients with metastatic melanoma treated by CTL-associated antigen-4 blockade.

PURPOSE: CTL-associated antigen 4 (CTLA-4) can inhibit T-cell activation and helps maintain peripheral self-tolerance. Previously, we showed immune-related adverse events (IRAE) and objective, durable clinical responses in patients with metastatic melanoma treated with CTLA-4 blockade. We have now treated 139 patients in two trials and have sufficient follow-up to examine factors associated with clinical response. EXPERIMENTAL DESIGN: A total of 139 patients with metastatic melanoma were treated: 54 patients received ipilimumab in conjunction with peptide vaccinations and 85 patients were treated with intra-patient dose escalation of ipilimumab and randomized to receive peptides in accordance with HLA-A*0201 status. RESULTS: Three patients achieved complete responses (CR; ongoing at 29+, 52+, and 53+ months); an additional 20 patients achieved partial responses (PR) for an overall objective response rate of 17%. The majority of patients (62%, 86 of 139) developed some form of IRAE, which was associated with a greater probability of objective antitumor response (P = 0.0004); all patients with CR had more severe IRAEs. Prior therapy with IFNalpha-2b was a negative prognostic factor, whereas prior high-dose interleukin-2 did not significantly affect the probability of response. There were no significant differences in the rate of clinical response or development of IRAEs between the two trials. The duration of tumor response was not affected by the use of high-dose steroids for abrogation of treatment-related toxicities (P = 0.23). There were no treatment-related deaths. CONCLUSION: In patients with metastatic melanoma, ipilimumab can induce durable objective clinical responses, which are related to the induction of IRAEs.

CTLA-4 . FasL induces early apoptosis of activated T cells by interfering with anti-apoptotic signals.

The fusion protein CTLA-4 . FasL, a paradigmatic "trans signal converter protein", can attach to APC surfaces and in effect convert B7-activating costimulator signals into inhibitory Fas receptor-generated signals. The present study investigates CTLA-4 . FasL's mechanism of action. A combination of p27(kip) and proliferating cell nuclear Ag Western blot and propidium iodide flow cytometric analysis showed no CTLA-4 . FasL effect on cell cycle entry and progression, pointing away from the kind of classical anergy associated with CTLA-4 . Ig. Significantly, CTLA-4 . FasL elicited apoptosis (as detected by annexin-V/propidium iodide costaining) as early as 24 h after T cell activation, suggesting that some coordinate signaling might be capacitating the Fas receptor. Significantly, CTLA-4 . FasL, but not CTLA-4 . Ig, anti-Fas mAb, or the two in combination, abrogated the usual increase in expression of the anti-apototic protein, cFLIP. Furthermore, activation of caspases 8 and 3 were not affected by CTLA-4 . FasL. These findings suggest a model for CTLA-4 . FasL action wherein there is coordinate triggering of a death receptor and suppression of a proapoptotic protein.

Cytotoxic T-lymphocyte-associated antigen-4.

Previously, the development of immune-based therapies has primarily focused on vaccines and cytokines, yielding benefit in a small percentage of patients. Recent advances in our understanding of the function of costimulatory molecules have revitalized enthusiasm in the development of immune therapies for cancer. This family of proteins possesses properties involved in both lymphocyte activation and immune-inhibitory functions. The costimulatory molecule with the greatest translation into the clinic thus far is CTL-associated antigen-4 (CTLA-4). CTLA-4 engagement leads to T-cell inhibition by two principle mechanisms. The first involves competitive binding with CD28 for B7 on the antigen-presenting cell. The second is direct intracellular inhibitory signals mediated by the CTLA-4 cytoplasmic tail. Numerous clinical trials testing the blockade of CTLA-4 signaling with fully human monoclonal antibodies have treated a variety of cancers, with the most experience in the treatment of metastatic melanoma. Significant antitumor activity as well as potential autoimmune-related toxicities have been observed. Further clinical investigation with CTLA-4 blockade, planned clinical trials testing manipulation of other costimulatory molecules, and continued improvement in understanding of costimulatory pathways present a new era of immune therapies for cancer patients.

The B7 family and cancer therapy: costimulation and coinhibition.

The activation and development of an adaptive immune response is initiated by the engagement of a T-cell antigen receptor by an antigenic peptide-MHC complex. The outcome of this engagement is determined by both positive and negative signals, costimulation and coinhibition, generated mainly by the interaction between the B7 family and their receptor CD28 family. The importance of costimulation and coinhibition of T cells in controlling immune responses is exploited by tumors as immune evasion pathways. Absence of the expression of costimulatory B7 molecules renders tumors invisible to the immune system, whereas enhanced expression of inhibitory B7 molecules protects them from effective T cell destruction. Therefore, the manipulation of these pathways is crucial for developing effective tumor immunotherapy. Translation of our basic knowledge of costimulation and coinhibition into early clinical trials has shown considerable promise.

Review: anti-CTLA-4 antibody ipilimumab: case studies of clinical response and immune-related adverse events.

The immune system is a powerful natural agent against cancer. Cytotoxic T lymphocyte antigen 4 (CTLA-4), a key negative regulator of T-cell responses, can restrict the antitumor immune response. Ipilimumab (MDX-010) is a fully human, monoclonal antibody that overcomes CTLA-4-mediated T-cell suppression to enhance the immune response against tumors. Preclinical and early clinical studies of patients with advanced melanoma show that ipilimumab promotes antitumor activity as monotherapy and in combination with treatments such as chemotherapy, vaccines, or cytokines. Emerging data on the kinetics of response to ipilimumab and associated adverse events are increasing our understanding about how to manage patients treated with this therapy. For example, short-term tumor progression prior to delayed regression has been observed in ipilimumab-treated patients, and objective responses may be of prolonged duration. In some patients clinical improvement manifests as stable disease, which may also extend for months or years. Immune-related adverse events (IRAEs) have been observed in patients after CTLA-4 blockade and most likely reflect the drug mechanism of action and corresponding effects on the immune system. Early clinical data suggest a correlation between IRAEs and response to ipilimumab treatment. This paper briefly reviews the results from several ongoing and completed ipilimumab clinical trials, provides a synopsis of current trials, and presents several cases that demonstrate the kinetics of antitumor responses and the relationship to IRAEs in patients receiving ipilimumab.

CTLA-4 blockade in murine bone marrow chimeras induces a host-derived antileukemic effect without graft-versus-host disease.

We studied the effect of CTLA-4 blockade on graft-versus-leukemia and graft-versus-host responses in a mouse model of minor histocompatibility-mismatched bone marrow transplantation. Early CTLA-4 blockade induced acute graft-versus-host disease. Delayed CTLA-4 blockade resulted in a lethal condition with lymphosplenomegaly, but with stable mixed T-cell chimerism, unchanged alloreactive T-cell frequencies and absent anti-host reactivity in vitro. In contrast, multiorgan lymphoproliferative disease with autoimmune hepatitis and circulating anti-DNA auto-antibodies were documented. Splenic lymphocytes exhibited ex vivo spontaneous proliferation and a marked proliferative response against host-type dendritic cells pulsed with syngeneic (host-type) tissue-peptides. Both phenomena were exclusively mediated by host and not donor T cells, supporting an autoimmune pathogenesis. Selectively host-derived T-cell immune reactivity was equally documented against leukemia-peptide-pulsed dendritic cells, and this was paralleled by a strong in vivo antileukemic effect in anti-CTLA-4-treated and subsequently leukemia-challenged chimeras. In conclusion, delayed CTLA-4 blockade induced a host-derived antileukemic effect, occurring in the context of an autoimmune syndrome and strictly separated from graft-versus-host disease. Both antileukemic and autoimmune responses depended on the allogeneic component, as neither effect was seen after syngeneic bone marrow transplantation. Our findings reveal the potential of using CTLA-4 blockade to establish antileukemic effects after allogeneic hematopoietic stem cell transplantation, provided autoimmunity can be controlled.

Enhancement of lymphokine-activated killer cell induction using anti-CD25 and anti-CTLA-4 monoclonal antibodies.

Immunosuppression may contribute to cancer progression, in which regulatory T (T-reg) cells have been demonstrated to play important roles. We investigated whether anti-CD25 (alpha-CD25) monoclonal antibody (mAb) and anti-cytotoxic T lymphocyte-associated antigen-4 (alpha-CTLA-4) mAb could augment in vitro proliferation and cytotoxic activity against cancer cell lines of lymphokine-activated killer (LAK) cells. Human LAK cells with immobilized alpha-CD3 Ab plus IL-2 were significantly augmented, including LAK/alpha-CD25 (10 microg ml, p=0.045) and LAK/alpha-CTLA-4 (5 microg/ml, p=0.025; 10 microg/ml, p=0.019). LAK/alpha-CD25 and LAK/alpha-CTLA-4 showed significant cytotoxic activities against gastric cancer cell lines (p<0.05). The phenotype of LAK cells showed that alpha-CD25 and alpha-CTLA-4 mAb more selectively induced the phenotype of CD8+ cells. The secretion of IFN-gamma increased significantly in LAK/alpha-CTLA-4 (p=0.032). alpha-CD25 mAb reduced intracellular CTLA-4 (p=0.0069), and alpha-CTLA-4 mAb reduced intracellular FOXP3 (p=0.049), respectively. These results suggest that LAK cells are highly augmented in the presence of alpha-CD25 mAb and alpha-CTLA-4 mAb through the possible mechanism of the suppression of T-reg.

NY-BR-1 protein expression in breast carcinoma: a mammary gland differentiation antigen as target for cancer immunotherapy.

NY-BR-1 is a recently identified differentiation antigen of the mammary gland. To use NY-BR-1 for T-cell-based immunotherapy, analysis of its co-expression with HLA class I antigens is required. In the present tissue microarray study, primary breast cancers (n = 1,444), recurrences (n = 88), lymph node (n = 525) and distant metastases (n = 91) were studied for NY-BR-1 expression using a novel monoclonal antibody. NY-BR-1 expression was compared with prognosis, estrogen receptor, HER2-status, EGFR and HLA class I antigen expression. NY-BR-1 was more frequently expressed in grade 1 (82%) than in grade 2 (69%) and grade 3 (46%) carcinomas (P < 0.0001). Moreover, NY-BR-1 expression correlated directly with estrogen receptor expression (P < 0.0001) and inversely correlated with HER2-status and EGFR expression (P < 0.0001 for both). Considering high expression level of co-expression, 198/1,321 (15%) primary breast carcinomas and 4/65 (6%) distant metastases expressed NY-BR-1 and HLA class I, suggesting that active immunotherapy can be applied to about 10% of breast cancer patients. Survival analysis showed an association of NY-BR-1 expression with better patient outcome (P = 0.015). No difference between NY-BR-1 expression of primary tumors and metastases could be found, indicating that the presence of NY-BR-1 in metastases can be deduced from their corresponding primary. Forty-three paired biopsies taken from patients before and after chemotherapy suggest that NY-BR-1 expression is not influenced by preceding chemotherapy (kappa = 0.89, P < 0.0001). In summary, the co-expression of NY-BR-1 with HLA class I antigens and its expression in metastases without modification by chemotherapy suggest that NY-BR-1 targeted immunotherapy represents a viable strategy in addition to other targeted cancer drug therapies of breast cancer.

CTLA-4 blockade differentially influences the outcome of non-lethal and lethal Plasmodium yoelii infections.

An immune response against malaria has to be tightly controlled. The production of pro-inflammatory cytokines is required to control parasites but the same cytokines are also involved in severe malaria. We have shown that CTLA-4 expression during Plasmodium berghei malaria dampens the immune response. This strain provokes a pro-inflammatory immune response that is associated with the pathology of cerebral malaria. Accordingly a blockade of CTLA-4 during the blood-stage of P. berghei malaria leads to an exacerbation of disease. To analyze the effects of a CTLA-4 blockade in a malaria model which is not prone to immune pathology we employed P. yoelii infection. Blood-stage infection led to a rapid induction of CTLA-4 on T cells. Using the non-lethal P. yoelii strain Py17NL we found that a blockade of CTLA-4 resulted in an increased T cell activation and IFN-gamma production, which was accompanied by a lower peak parasitemia and earlier parasite clearance. In contrast, blockade of CTLA-4 during infection with a P. yoelii strain exhibiting a higher parasitemia induced markedly increased serum-levels of TNF-alpha, which was associated with severe inflammation and reduced survival.