Inhibition of Human Breast Carcinoma Growth by a Soluble Recombinant Human CD40 Ligand

Soluble CD40 Ligand as a Promising Biomarker in Cancer Diagnosis

Cancer remains a significant challenge in medicine due to its complexity and heterogeneity. Biomarkers have emerged as vital tools for cancer research and clinical practice, facilitating early detection, prognosis assessment, and treatment monitoring. Among these, CD40 ligand (CD40L) has gained attention for its role in immune response modulation. Soluble CD40 ligand (sCD40L) has shown promise as a potential biomarker in cancer diagnosis and progression, reflecting interactions between immune cells and the tumor microenvironment. This review explores the intricate relationship between sCD40L and cancer, highlighting its diagnostic and prognostic potential. It discusses biomarker discovery, emphasizing the need for reliable markers in oncology, and elucidates the roles of CD40L in inflammatory responses and interactions with tumor cells. Additionally, it examines sCD40L as a biomarker, detailing its significance across various cancer types and clinical applications. Moreover, the review focuses on therapeutic interventions targeting CD40L in malignancies, providing insights into cellular and gene therapy approaches and recombinant protein-based strategies. The clinical effectiveness of CD40L-targeted therapy is evaluated, underscoring the need for further research to unlock the full potential of this signaling pathway in cancer management.

Aged breast matrix bound vesicles promote breast cancer invasiveness

Aging is one of the inherent risk factors for breast cancer. Although the influence of age-related cellular alterations on breast cancer development has been extensively explored, little is known about the alterations in the aging breast tissue microenvironment, specifically the extracellular matrix (ECM). Here, for the first time in literature, we have identified tissue resident matrix bound vesicles (MBVs) within the healthy mouse breast ECM, investigated and compared their characteristics in young and aged healthy breast tissues, and studied the effects of these MBVs on normal (KTB21) and cancerous (MDA-MB-231) human mammary epithelial cells with respect to the tissue age that they are extracted from. Using vesicle labeling technology, we were able to visualize cellular uptake of the MBVs directly from the native decellularized tissue sections, showing that these MBVs have regulatory roles in the tissue microenvironment. We mimicked the ECM by embedding the MBVs in collagen gels, and showed that MBVs could be taken up by the cells. The miRNA and cytokine profiling showed that MBVs shifted towards a more tumorigenic and invasive phenotype with age, as evidenced by the more pronounced presence of cancer-associated cytokines, and higher expression levels of oncomiRs miR-10b, miR-30e, and miR-210 in MBVs isolated from aged mice. When treated with MBVs or these upregulated factors, KTB21 and MDA-MB-231 cells showed significantly higher motility and invasion compared to untreated controls. Treatment of cells with a cocktail of miRNAs (miR-10b, miR-30e, and miR-210) or with the agonist of adiponectin (AdipoRon), which both were enriched in the aged MBVs, recapitulated the effect of aged MBVs on cells. This study shows for the first time that the MBVs have a regulatory role in the tissue microenvironment and that the MBV contents change towards cancer-promoting upon aging. Studying the effects of MBVs and their cargos on cellular behavior could lead to a better understanding of the critical roles of MBVs played in breast cancer progression and metastasis.

The CD40 agonist HERA-CD40L results in enhanced activation of antigen presenting cells, promoting an anti-tumor effect alone and in combination with radiotherapy

Introduction

The ability to modulate and enhance the anti-tumor immune responses is critical in developing novel therapies in cancer. The Tumor Necrosis Factor (TNF) Receptor Super Family (TNFRSF) are potentially excellent targets for modulation which result in specific anti-tumor immune responses. CD40 is a member of the TNFRSF and several clinical therapies are under development. CD40 signaling plays a pivotal role in regulating the immune system from B cell responses to myeloid cell driven activation of T cells. The CD40 signaling axis is well characterized and here we compare next generation HERA-Ligands to conventional monoclonal antibody based immune modulation for the treatment of cancer.

Methods & results

HERA-CD40L is a novel molecule that targets CD40 mediated signal transduction and demonstrates a clear mode of action in generating an activated receptor complex via recruitment of TRAFs, cIAP1, and HOIP, leading to TRAF2 phosphorylation and ultimately resulting in the enhanced activation of key inflammatory/survival pathway and transcription factors such asNFkB, AKT, p38, ERK1/2, JNK, and STAT1 in dendritic cells. Furthermore, HERA-CD40L demonstrated a strong modulation of the tumor microenvironment (TME) via the increase in intratumoral CD8+ T cells and the functional switch from pro-tumor macrophages (TAMs) to anti-tumor macrophages that together results in a significant reduction of tumor growth in a CT26 mouse model. Furthermore, radiotherapy which may have an immunosuppressive modulation of the TME, was shown to have an immunostimulatory effect in combination with HERA-CD40L. Radiotherapy in combination with HERA-CD40L treatment resulted in an increase in detected intratumoral CD4+/8+ T cells compared to RT alone and, additionally, the repolarization of TAMs was also observed, resulting in an inhibition of tumor growth in a TRAMP-C1 mouse model.

Discussion

Taken together, HERA-CD40L resulted in activating signal transduction mechanisms in dendritic cells, resulting in an increase in intratumoral T cells and manipulation of the TME to be pro-inflammatory, repolarizing M2 macrophages to M1, enhancing tumor control.

Aged Breast Matrix Bound Vesicles Promote Breast Cancer Invasiveness

Aging is one of the inherent risk factors for breast cancer. Although the influence of age-related cellular alterations on breast cancer development has been extensively explored, little is known about the alterations in the aging breast tissue microenvironment, specifically the extracellular matrix (ECM). Here, for the first time in literature, we have identified tissue resident matrix bound vesicles (MBVs) within the healthy mouse breast ECM, investigated and compared their characteristics in young and aged healthy breast tissues, and studied the effects of these MBVs on normal (KTB21) and cancerous (MDA-MB-231) human mammary epithelial cells with respect to the tissue age that they are extracted from. Using vesicle labeling technology, we were able to visualize cellular uptake of the MBVs directly from the native decellularized tissue sections, showing that these MBVs have regulatory roles in the tissue microenvironment. We mimicked the ECM by embedding the MBVs in collagen gels, and showed that MBVs could be taken up by the cells. The miRNA and cytokine profiling showed that MBVs shifted towards a more tumorigenic and invasive phenotype with age, as evidenced by the more pronounced presence of cancer-associated cytokines, and higher expression levels of oncomiRs miR-10b, miR-30e, and miR-210 in MBVs isolated from aged mice. When treated with MBVs or these upregulated factors, KTB21 and MDA-MB-231 cells showed significantly higher motility and invasion compared to untreated controls. Treatment of cells with a cocktail of miRNAs (miR-10b, miR-30e, and miR-210) or with the agonist of adiponectin (AdipoRon), which both were enriched in the aged MBVs, recapitulated the effect of aged MBVs on cells. This study shows for the first time that the MBVs have a regulatory role in the tissue microenvironment and that the MBV contents change towards cancer-promoting upon aging. Studying the effects of MBVs and their cargos on cellular behavior could lead to a better understanding of the critical roles of MBVs played in breast cancer progression and metastasis.

Spatial characterization and quantification of CD40 expression across cancer types

BACKGROUND

CD40, a TNF receptor family member, is expressed by a variety of immune cells and is involved in the activation of both adaptive and innate immune responses. Here, we used quantitative immunofluorescence (QIF) to evaluate CD40 expression on the tumor epithelium of solid tumors in large patient cohorts of lung, ovarian, and pancreatic cancers.

METHODS

Tissue samples from nine different solid tumors (bladder, breast, colon, gastric, head and neck, non-small cell lung cancer (NSCLC), ovarian, pancreatic and renal cell carcinoma), constructed in tissue microarray format, were initially assessed for CD40 expression by QIF. CD40 expression was then evaluated on the large available patient cohorts for three of the tumor types demonstrating high CD40 positivity rate; NSCLC, ovarian and pancreatic cancer. The prognostic impact of CD40 expression on tumor cells was also investigated.

RESULTS

CD40 expression on tumor cells was found to be common, with 80% of the NSCLC population, 40% of the ovarian cancer population, and 68% of the pancreatic adenocarcinoma population displaying some degree of CD40 expression on cancer cells. All of three of these cancer types displayed considerable intra-tumoral heterogeneity of CD40 expression, as well as partial correlation between expression of CD40 on tumor cells and on surrounding stromal cells. CD40 was not found to be prognostic for overall survival in NSCLC, ovarian cancer, or pancreatic adenocarcinoma.

CONCLUSIONS

The high percentage of tumor cells expressing CD40 in each of these solid tumors should be considered in the development of therapeutic agents designed to target CD40.

CD40LG as a Prognostic Molecular Marker Regulates Tumor Microenvironment Through Immune Process in Breast Cancer

Purpose

Breast cancer (BRCA) is the second most common malignancy in the world and the most common in women. Here, we utilized publicly available BRCA dataset to investigate potential prognosis-related genes through integrated bioinformatics analysis.

Materials and Methods

BRCA dataset was obtained from the Cancer Genome Atlas (TCGA) database. The ESTIMATE algorithm was used to calculate the ImmuneScores and StromalScores of the samples and then divided them into high- and low-score groups based on the median score. Common differentially expressed genes (DEGs) were identified through differential expression analysis. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed. The core prognostic genes were the intersection of hub genes from PPI network and prognostic genes from univariate Cox proportional hazard regression analysis. Finally, the CIBERSORT algorithm was used to calculate proportions of 22 tumor-infiltrating immune cells (TICs) in BRCA samples.

Results

A total of 486 DEGs were identified. These genes were mainly enriched in immune-related pathways. Crossover genes between the hub genes and the prognostic genes were CD2 and CD40LG. CD40LG was further investigated in this study. CD40LG was downregulated in BRCA samples compared with normal samples, and a lower CD40LG expression was associated with advanced tumor stages and a poor prognosis. CD40LG was shown to be involved in immune-related pathways of BRCA by Gene Set Enrichment Analysis. Finally, 14 TICs were found to have a close relationship with CD40LG.

Conclusion

CD40LG was found to be a core prognostic gene related to tumor microenvironment and deeply involved in immune-related pathways in BRCA. Our findings may provide new insights for exploring the molecular mechanisms of BRCA and developing new immunotherapies for the disease.

CD154 Resistant to Cleavage from Intracellular Milieu and Cell Surface Induces More Potent CD40-Mediated Responses

In addition to the membrane-bound form, CD154 also exists as a soluble molecule originating from an intracellular and membrane cleavage. We have previously shown that CD154 cleavage from T cell surface is mediated by CD40 and involves the action of ADAM10/ADAM17 enzymes. In the aim of defining the importance of CD154 maintained on cell surface, we generated a CD154 mutated at the cleavage site. Our data show that the double mutation of E112 and M113 residues of CD154 abolishes its spontaneous release and the CD40-mediated cleavage from cell surface but does not affect its binding to CD40. We also demonstrated that both the release of CD154 from the intracellular milieu and its CD40-mediated cleavage from cell surface are highly dependent on ADAM10/ADAM17 enzymes. The CD154-EM mutant was shown capable of inducing a more prominent apoptotic response in susceptible B cell lines than the wild-type (WT) form of the molecule. In addition, human B cells cultured in the presence of the CD154-EM mutant exhibited upregulated proliferative responses compared with the CD154-WT. The CD154-EM mutant was also shown to trigger differentiation of human B cells, reflected by an increased Ig production, more significantly than CD154-WT. Thus, our data strongly suggest that cleavage-resistant CD154 is a more prominent stimulant than the cleavable form of the molecule. Therefore, a maintained expression of CD154 on cell membrane and a disturbed cleavage of the molecule could be a mechanism by which CD154 is involved in some pathological conditions and should be revisited.

Future of immunotherapy in pancreas cancer and the trials, tribulations and successes thus far

Pancreas ductal adenocarcinoma (PDAC) has a dismal prognosis with a 5-year survival rate of 10%. Currently, chemotherapy remains the standard of care for systemic treatment. Immunotherapy with checkpoint inhibitors unfortunately has not been found to be effective in the treatment of PDAC to date, likely due to the highly desmoplastic and immunosuppressive tumor microenvironment (TME). Treatment targeting pathways against the immunosuppressive mechanisms of PDAC are of mounting interest to improve outcomes in PDAC. In this review, we discuss prior efforts and the current state of immunotherapy in PDAC. We will also review the emerging targets and treatments with significant clinical potential for the treatment of PDAC such as: CD40 pathway, the adenosine pathway, the CXCR4/CXCL12 axis, the CCR2/CCL2 axis, IDO pathway, and others.

Molecular basis and therapeutic implications of CD40/CD40L immune checkpoint

The CD40 receptor and its ligand CD40L is one of the most critical molecular pairs of the stimulatory immune checkpoints. Both CD40 and CD40L have a membrane form and a soluble form generated by proteolytic cleavage or alternative splicing. CD40 and CD40L are widely expressed in various types of cells, among which B cells and myeloid cells constitutively express high levels of CD40, and T cells and platelets express high levels of CD40L upon activation. CD40L self-assembles into functional trimers which induce CD40 trimerization and downstream signaling. The canonical CD40/CD40L signaling is mediated by recruitment of TRAFs and NF-κB activation, which is supplemented by signal pathways such as PI3K/AKT, MAPKs and JAK3/STATs. CD40/CD40L immune checkpoint leads to activation of both innate and adaptive immune cells via two-way signaling. CD40/CD40L interaction also participates in regulating thrombosis, tissue inflammation, hematopoiesis and tumor cell fate. Because of its essential role in immune activation, CD40/CD40L interaction has been regarded as an attractive immunotherapy target. In recent years, significant advance has been made in CD40/CD40L-targeted therapy. Various types of agents, including agonistic/antagonistic monoclonal antibodies, cellular vaccines, adenoviral vectors and protein antagonist, have been developed and evaluated in early-stage clinical trials for treating malignancies, autoimmune diseases and allograft rejection. In general, these agents have demonstrated favorable safety and some of them show promising clinical efficacy. The mechanisms of benefits include immune cell activation and tumor cell lysis/apoptosis in malignancies, or immune cell inactivation in autoimmune diseases and allograft rejection. This review provides a comprehensive overview of the structure, processing, cellular expression pattern, signaling and effector function of CD40/CD40L checkpoint molecules. In addition, we summarize the progress, targeted diseases and outcomes of current ongoing and completed clinical trials of CD40/CD40L-targeted therapy.

Targeting eukaryotic proteases for natural products-based drug development

Covering: up to April 2020 Proteases are involved in the regulation of many physiological processes. Their overexpression and dysregulated activity are linked to diseases such as hypertension, diabetes, viral infections, blood clotting disorders, respiratory diseases, and cancer. Therefore, they represent an important class of therapeutic targets. Several protease inhibitors have reached the market and >60% of them are directly related to natural products, even when excluding synthetic natural product mimics. Historically, natural products have been a valuable and validated source of therapeutic agents, as over half of the marketed drugs across targets and diseases are inspired by natural product structures. In the past two decades the number of new protease inhibitors discovered from nature has sharply increased. Additionally, the availability of 3D structural information for proteases has permitted structure-based design and accelerated the synthesis of optimized lead structures with improved potency and selectivity profiles, resulting in some of the most-potent-in-class inhibitors. These discoveries were oftentimes maximized by in-depth biological assessments of lead inhibitors, linking them to a relevant disease state. This review will discuss some of the current and emerging drug targets and their involvement in various disease processes, highlighting selected success stories behind several FDA-approved protease inhibitors that have natural products scaffolds as well as recent selected pharmacologically well-characterized inhibitors derived from marine or terrestrial sources.

The Use of Anti-CD40 mAb in Cancer

Immunomodulatory monoclonal antibody (mAb) therapy is at the forefront of developing cancer therapeutics with numerous targeted agents proving highly effective in selective patients at stimulating protective host immunity, capable of eradicating established tumours and leading to long-term disease-free states. The cell surface marker CD40 is expressed on a range of immune cells and transformed cells in malignant states whose signalling plays a critical role in modulating adaptive immune responses. Anti-CD40 mAb therapy acts via multiple mechanisms to stimulate anti-tumour immunity across a broad range of lymphoid and solid malignancies. A wealth of preclinical research in this field has led to the successful development of multiple anti-CD40 mAb agents that have shown promise in early-phase clinical trials. Significant progress has been made to enhance the engagement of antibodies with immune effectors through their interactions with Fcγ receptors (FcγRs) by the process of Fc engineering. As more is understood about how to best optimise these agents, principally through the fine-tuning of mAb structure and choice of synergistic partnerships, our ability to generate robust, clinically beneficial anti-tumour activity will form the foundation for the next generation of cancer therapeutics.

The Expression of CD154 by Kaposi's Sarcoma Cells Mediates the Anti-Apoptotic and Migratory Effects of HIV-1-Tat Protein

Kaposi's sarcoma (KS) is a malignancy associated to conditions of immune system impairment such as HIV-1 infection and post-transplantation therapy. Here we report that HIV-1-Tat protein, at concentrations well below those detected in AIDS patients, up-regulates the expression of both CD40 and CD154 on KS cells. This occurred also in the presence of vincristine, that at doses shown to induce apoptosis decreased the expression of both CD40 and CD154 on KS cells. The treatment with a soluble CD40-muIg fusion protein (CD40 fp) that prevents the binding of CD154 with cell surface CD40, as well as the transfection with a vector for soluble CD40 (KS sCD40), decreased the anti-apoptotic effect of Tat. Moreover, Tat-induced motility of KS cells was inhibited by soluble CD40 fp. Tat also enhanced the expression of intracellular proteins known to transduce signals triggered by CD40 engagement, in particular TRAF-3. Tat as well as soluble CD154 (sCD154) prevented vincristine-induced reduction of TRAF-3 in KS cells transfected with a vector for neomycin resistance (KS psv-neo), but not in KS sCD40. Immunoprecipitation studies showed that Tat induced CD40 / TRAF-3 association and that this binding was abrogated upon the incubation with the soluble CD40 fp. These data suggest that Tat activates the CD40-CD154 pathway by enhancing the membrane expression of CD40 and in particular of CD154, and by activating the TRAF-3-dependent signaling pathway of CD40. These findings indicate that the CD40-CD154 pathway mediates the anti-apoptotic and migratory effects of HIV-1-Tat, suggesting the potential therapeutic benefits of blocking CD40 activation in HIV-1-associated KS.

The hyper IgM syndromes: Epidemiology, pathogenesis, clinical manifestations, diagnosis and management

Hyper Immunoglobulin M syndrome (HIGM) is a rare primary immunodeficiency disorder characterized by low or absent levels of serum IgG, IgA, IgE and normal or increased levels of serum IgM. Various X-linked and autosomal recessive/dominant mutations have been reported as the underlying cause of the disease. Based on the underlying genetic defect, the affected patients present a variety of clinical manifestations including pulmonary and gastrointestinal complications, autoimmune disorders, hematologic abnormalities, lymphoproliferation and malignancies which could be controlled by multiple relevant therapeutic approaches. Herein, the epidemiology, pathogenesis, clinical manifestations, diagnosis, management, prognosis and treatment in patients with HIGM syndrome have been reviewed.

Expression of CD40 in Ovarian Cancer and Adenovirus-Mediated CD40 Ligand Therapy on Ovarian Cancer in Vitro

Aims and Background

To test the expression level of CD40 on ovarian cancer tissues and its correlation to clinicopathological features of patients and to evaluate the therapeutic effectiveness of adenovirus-mediated CD40 ligand on ovarian cancer in vitro.

Material and Methods

The expression of CD40 on paraffin-embedded ovarian cancer tissues (n = 58) and normal ovarian tissues (n = 15) was tested by immunohistochemistry, and CD40 expression on ovarian cancer cells derived from fresh surgical specimens was tested by flow cytometry analysis. The apoptosis-inducing effects of adenovirus-mediated CD40 ligand therapy on ovarian cancer cells derived from fresh surgical specimens were analyzed by flow cytometry analysis and TUNEL assay.

Results

CD40 expression was detected in 60.3% (35/58) of paraffin-embedded ovarian cancer tissues and 73.3% (11/15) of fresh ovarian cancer tissues, but not in normal ovarian tissues (n = 15). CD40 expression was significantly correlated with FIGO stage of ovarian cancer. Adenovirus-mediated CD40 ligand therapy induced significant apoptosis effects on ovarian cancer cells derived from fresh surgical specimens in vitro compared to null adenovirus vector and phosphate-buffered saline.

Conclusions

Our results suggested the therapeutic potential of adenovirus-mediated CD40 ligand on ovarian cancer, especially on the late stage of ovarian cancer.

New Immunotherapy Strategies in Breast Cancer

Breast cancer is the most commonly diagnosed cancer among women. Therapeutic treatments for breast cancer generally include surgery, chemotherapy, radiotherapy, endocrinotherapy and molecular targeted therapy. With the development of molecular biology, immunology and pharmacogenomics, immunotherapy becomes a promising new field in breast cancer therapies. In this review, we discussed recent progress in breast cancer immunotherapy, including cancer vaccines, bispecific antibodies, and immune checkpoint inhibitors. Several additional immunotherapy modalities in early stages of development are also highlighted. It is believed that these new immunotherapeutic strategies will ultimately change the current status of breast cancer therapies.

Intravenously usable fully serotype 3 oncolytic adenovirus coding for CD40L as an enabler of dendritic cell therapy

Vaccination with dendritic cells (DCs), the most potent professional antigen-presenting cells in the body, is a promising approach in cancer immunotherapy. However, tumors induce immunosuppression in their microenvironment that suppresses and impairs the function of DCs. Therefore, human clinical trials with DC therapy have often been disappointing. To improve the therapeutic efficacy and to overcome the major obstacles of DC therapy, we generated a novel adenovirus, Ad3-hTERT-CMV-hCD40L, which is fully serotype 3 and expresses hCD40L for induction of antitumor immune response. The specific aim is to enhance DCs function. Data from a human cancer patient indicated that this capsid allows effective transduction of distant tumors through the intravenous route. Moreover, patient data suggested that virally produced hCD40L can activate DCs in situ. The virus was efficient in vitro and had potent antitumor activity in vivo. In a syngeneic model, tumors treated with Ad5/3-CMV-mCD40L virus plus DCs elicited greater antitumor effect as compared with either treatment alone. Moreover, virally coded CD40L induced activation of DCs, which in turn, lead to the induction of a Th1 immune response and increased tumor-specific T cells. In conclusion, Ad3-hTERT-CMV-hCD40L is promising for translation into human trials. In particular, this virus could enable successful dendritic cell therapy in cancer patients.

Improving Adoptive T Cell Therapy: The Particular Role of T Cell Costimulation, Cytokines, and Post-Transfer Vaccination

Adoptive cellular therapy (ACT) is a form of immunotherapy whereby antigen-specific T cells are isolated or engineered, expanded ex vivo, and transferred back to patients. Clinical benefit after ACT has been obtained in treatment of infection, various hematological malignancies, and some solid tumors; however, due to poor functionality and persistence of the transferred T cells, the efficacy of ACT in the treatment of most solid tumors is often marginal. Hence, much effort is undertaken to improve T cell function and persistence in ACT and significant progress is being made. Herein, we will review strategies to improve ACT success rates in the treatment of cancer and infection. We will deliberate on the most favorable phenotype for the tumor-specific T cells that are infused into patients and on how to obtain T cells bearing this phenotype by applying novel ex vivo culture methods. Moreover, we will discuss T cell function and persistence after transfer into patients and how these factors can be manipulated by means of providing costimulatory signals, cytokines, blocking antibodies to inhibitory molecules, and vaccination. Incorporation of these T cell stimulation strategies and combinations of the different treatment modalities are likely to improve clinical response rates further.

CD40 ligand induces RIP1-dependent, necroptosis-like cell death in low-grade serous but not serous borderline ovarian tumor cells

Ovarian high-grade serous carcinomas (HGSCs) and invasive low-grade serous carcinomas (LGSCs) are considered to be distinct entities. In particular, LGSCs are thought to arise from non-invasive serous borderline ovarian tumors (SBOTs) and show poor responsiveness to conventional chemotherapy. The pro-apoptotic effects of CD40 ligand (CD40L) have been demonstrated in HGSC, though the underlying mechanisms are not fully understood. Conversely, the therapeutic potential of the CD40L-CD40 system has yet to be evaluated in LGSC. We now show that CD40 protein is focally expressed on tumor cells in two of five primary LGSCs compared with no expression in eight primary SBOTs. Treatment with CD40L or agonistic CD40 antibody decreased the viability of LGSC-derived MPSC1 and VOA1312 cells, but not SBOT3.1 cells. Small interfering RNA (siRNA) targeting CD40 was used to show that it is required for these reductions in cell viability. CD40L treatment increased cleaved caspase-3 levels in MPSC1 cells though, surprisingly, neither pan-caspase inhibitor nor caspase-3 siRNA reversed or even attenuated CD40L-induced cell death. In addition, CD40-induced cell death was not affected by knockdown of the mitochondrial proteins apoptosis-inducing factor (AIF) and endonuclease G (EndoG). Interestingly, CD40L-induced cell death was blocked by necrostatin-1, an inhibitor of receptor-interacting protein 1 (RIP1), and attenuated by inhibitors of RIP3 (GSK'872) or MLKL (mixed lineage kinase domain-like; necrosulfonamide). Our results indicate that the upregulation of CD40 may be relatively common in LGSC and that CD40 activation induces RIP1-dependent, necroptosis-like cell death in LGSC cells.

Transitional cell carcinoma in a patient with X-linked hyperimmunoglobulin M syndrome

Patients with X-linked hyperimmunoglobulin M syndrome (XHIGM) have a defective CD40-CD40 ligand system and further immunoglobulin class-switching. They may present with recurrent infection and malignancy involving the liver, pancreas or biliary tract. We report here a case of poorly differentiated transitional cell carcinoma in a young man with XHIGM even on regular treatment and discuss the possible pathogenesis. Given that the triggering of the CD40-CD40 ligand system has been found to improve tumor immunogenicity in recent studies, future immunotherapy targeting the CD40 ligand for these patients may be feasible to prolong their survival.

Multifunctional CD40L: pro- and anti-neoplastic activity

The CD40 ligand is a type I transmembrane protein that belongs to a tumor necrosis factor (TNF) superfamily. It is present not only on the surface of activated CD4+ T cells, B cells, blood platelets, monocytes, and natural killer (NK) cells but also on cancer cells. The receptor for ligand is constitutively expressed on cells, TNF family protein: CD40. The role of the CD40/CD40L pathway in the induction of body immunity, in inflammation, or in hemostasis has been well documented, whereas its involvement in neoplastic disease is still under investigation. CD40L ligand may potentiate apoptosis of tumor cells by activation of nuclear factor-κB (NF-κB), AP-1, CD95, or caspase-depended pathways and stimulate host immunity to defend against cancer. Although CD40L has a major contribution to anti-cancer activity, many reports point at its ambivalent nature. CD40L enhance release of strongly pro-angiogenic factor, vascular endothelial growth factor (VEGF), and activator of coagulation, TF, the level of which is correlated with tumor metastasis. CD40L involvement in the inhibition of tumor progression has led to the emergence of not only therapy using recombinant forms of the ligand and vaccines in the treatment of cancer but also therapy consisting of inhibiting platelets-main source of CD40L. This article is a review of studies on the ambivalent role of CD40L in neoplastic diseases.

An autologous in situ tumor vaccination approach for hepatocellular carcinoma. 2. Tumor-specific immunity and cure after radio-inducible suicide gene therapy and systemic CD40-ligand and Flt3-ligand gene therapy in an orthotopic tumor model

Diffuse hepatocellular carcinoma (HCC) is a lethal disease that radiation therapy (RT) currently has a limited role in treating because of the potential for developing fatal radiation-induced liver disease. However, recently diffuse HCC, "radio-inducible suicide gene therapy" has been shown to enhance local tumor control and residual microscopic disease within the liver for diffuse HCC, by using a combination of chemoactivation and molecular radiosensitization. We have demonstrated that the addition of recombinant adenovirus-expressing human Flt3 ligand (Adeno-Flt3L) after radio-inducible suicide gene therapy induced a Th1-biased, immune response and enhanced tumor control in an ectopic model of HCC. We hypothesized that sequential administration of recombinant adenovirus-expressing CD40L (Adeno-CD40L) could further potentiate the efficacy of our trimodal therapy with RT + HSV-TK + Adeno-Flt3L. We examined our hypothesis in an orthotopic model of diffuse HCC using BNL1ME A.7R.1 (BNL) cells in Balb/c mice. BNL murine hepatoma cells (5 × 10(4)) transfected with an expression vector of HSV-TK under the control of a radiation-inducible promoter were injected intraportally into BALB/cJ mice. Fourteen days after the HCC injection, mice were treated with a 25 Gy dose of radiation to the whole liver, followed by ganciclovir (GCV) treatment and systemic adenoviral cytokine gene therapy (Flt3L or CD40L or both). Untreated mice died in 27 ± 4 days. Radiation therapy alone had a marginal effect on survival (median = 35 ± 7 days) and the addition of HSV-TK/GCV gene therapy improved the median survival to 47 ± 6 days. However, the addition of Adeno-Flt3L to radiation therapy and HSV-TK/GCV therapy significantly (P = 0.0005) increased survival to a median of 63 ± 20 days with 44% (7/16) of the animals still alive 116 days after tumor implantation. The curative effect of Flt3L was completely abolished when using immunodeficient nude mice or mice depleted for CD4, CD8 and natural killer cells. The addition of Adeno-CD40L further improved the median survival of animals to 80 ± 15 days and this effect was abolished only when using anti-CD8 antibodies. Chromium-51 (51Cr) release assay showed cytotoxic T lymphocyte (CTL) activation, suggesting efficient dendritic cell (DC) activation with CTL activation after the treatment. Furthermore, when surviving mice were rechallenged with BNL-ETK cells on the foot pad, RT + HSV-TK/GCV + Flt3L + CD40L-treated mice developed a small tumor on day 56 but the tumor eventually disappeared after 105 days. Mice treated with RT + HSV-TK/GCV + Flt3L showed a slowed tumor growth curve compared with untreated mice. Therefore, combination therapy using Flt3L to induce DC proliferation and CD40L to enhance DC maturation holds great promise for immunomodulation of radiation therapy to enhance HCC tumor control and prevent progression of disease in patients with diffuse HCC.

Enhanced therapeutic anti-tumor immunity induced by co-administration of 5-fluorouracil and adenovirus expressing CD40 ligand

Bystander immune activation by chemotherapy has recently gained extensive interest and provided support for the clinical use of chemotherapeutic agents in combination with immune enhancers. The CD40 ligand (CD40L; CD154) is a potent regulator of the anti-tumor immune response and recombinant adenovirus (RAd)-mediated CD40L gene therapy has been effective in various cancer models and in man. In this study we have assessed the combined effect of local RAd-CD40L and 5-fluorouracil (5-FU) administration on a syngeneic MB49 mouse bladder tumor model. Whereas MB49 cells implanted into immunocompetent mice responded poorly to RAd-CD40L or 5-FU alone, administration of both agents dramatically decreased tumor growth, increased survival of the mice and induced systemic MB49-specific immunity. This combination treatment was ineffective in athymic nude mice, highlighting an important role for T cell mediated anti-tumor immunity for full efficacy. 5-FU up-regulated the expression of Fas and immunogenic cell death markers in MB49 cells and cytotoxic T lymphocytes from mice receiving RAd-CD40L immunotherapy efficiently lysed 5-FU treated MB49 cells in a Fas ligand-dependent manner. Furthermore, local RAd-CD40L and 5-FU administration induced a shift of myeloid-derived suppressor cell phenotype into a less suppressive population. Collectively, these data suggest that RAd-CD40L gene therapy is a promising adjuvant treatment to 5-FU for the management of bladder cancer.

Activation of CD40 by soluble recombinant human CD40 ligand inhibits human glioma cells proliferation via nuclear factor-κB signaling pathway

As CD40 transduces activation signals involved in inflammatory and immune disorders, we explored the expression and response to CD40 engagement in human glioma cell lines in this study. The CD40 expression in BT-325 and U251 cells was flow cytometrically detected. The cells were incubated with srhCD40L for 72 h to assess its effects on cell growth in vitro. TNF-α expression was quantified by real-time PCR, and protein expression was analyzed by ELISA. The I-κb mRNA was detected by RT-PCR. I-κB expression decreased after stimulation with 1 μg/mL srhCD40L, but it was upregulated after the cells were pretreated with CD40 antibody. srhCD40L significantly inhibited the proliferation of the CD40+ human glioma cells. The stimulation of CD40+ glioma cells with soluble CD40L (CD154) up-regulated the expression of TNF-α at both mRNA and protein levels. We are led to conclude that CD40L/CD40 could inhibit human glioma cells through I-κb signaling pathway. Interferon-γ can augment CD40 expression and the inhibitory effect of CD40 ligand on cell growth in vitro. These results suggest that srhCD40L may benefit the therapy strategy of glioma.

Immune response is an important aspect of the antitumor effect produced by a CD40L-encoding oncolytic adenovirus

Oncolytic adenovirus is an attractive platform for immunotherapy because virus replication is highly immunogenic and not subject to tolerance. Although oncolysis releases tumor epitopes and provides costimulatory danger signals, arming the virus with immunostimulatory molecules can further improve efficacy. CD40 ligand (CD40L, CD154) induces apoptosis of tumor cells and triggers several immune mechanisms, including a T-helper type 1 (T(H)1) response, which leads to activation of cytotoxic T cells and reduction of immunosuppression. In this study, we constructed a novel oncolytic adenovirus, Ad5/3-hTERT-E1A-hCD40L, which features a chimeric Ad5/3 capsid for enhanced tumor transduction, a human telomerase reverse transcriptase (hTERT) promoter for tumor selectivity, and human CD40L for increased efficacy. Ad5/3-hTERT-E1A-hCD40L significantly inhibited tumor growth in vivo via oncolytic and apoptotic effects, and (Ad5/3-hTERT-E1A-hCD40L)-mediated oncolysis resulted in enhanced calreticulin exposure and HMGB1 and ATP release, which were suggestive of immunogenicity. In two syngeneic mouse models, murine CD40L induced recruitment and activation of antigen-presenting cells, leading to increased interleukin-12 production in splenocytes. This effect was associated with induction of the T(H)1 cytokines IFN-γ, RANTES, and TNF-α. Tumors treated with Ad5/3-CMV-mCD40L also displayed an enhanced presence of macrophages and cytotoxic CD8(+) T cells but not B cells. Together, our findings show that adenoviruses coding for CD40L mediate multiple antitumor effects including oncolysis, apoptosis, induction of T-cell responses, and upregulation of T(H)1 cytokines.

Critical role of CD40-mediated autocrine tumor necrosis factor-alpha in potentiation of cisplatin-induced cytotoxicity in cancer cells

Activation of CD40, a member of the tumor necrosis factor receptor (TNF-R) family, results in growth inhibition or apoptosis in some tumor cells, making CD40 a potential antitumor therapeutic target. Although it is known that CD40 is able to induce tumor necrosis factor-alpha (TNF-α) secretion and potentiate cisplatin's anticancer activity, whether TNF-α induction is involved in sensitizing cisplatin by CD40 has not been addressed. In this report, we provide evidence substantiating an important role of autocrine TNF-α in potentiation of cisplatin-induced apoptosis by recombinant soluble CD40 ligand (rsCD40L) in different human cancer cell lines. Activation of CD40 by rsCD40L induces two phases of autocrine TNF-α: the rapid early phase involving p38 MAP kinase and the robust and persistent late phase through enhanced tnf-α gene transcription. Blocking TNF-α with either a specific TNFR1 siRNA or a neutralizing anti-TNF-α antibody dramatically attenuated the potentiation effect of rsCD40L on cisplatin-induced cancer cell death. These results reveal an important role of TNF-α induction in CD40's chemosensitization activity and suggest that modulating TNF-α autocrine from cancer cells is an effective option for increasing the anticancer value of chemotherapeutics such as cisplatin.

The CD40 agonist antibody CP-870,893 enhances dendritic cell and B-cell activity and promotes anti-tumor efficacy in SCID-hu mice

CD40 is a member of the TNF family of receptors that has been shown to play a crucial role in enhancing dendritic cell activity and fostering anti-tumor immune responses. In this study, we demonstrate the in vitro properties and in vivo efficacious activity of the CD40 agonist antibody, CP-870,893. CP-870,893 is a fully human, IgG2 antibody that selectively interacts with CD40 at a site distinct from its ligand-binding region with a KD of 0.4 nM. It enhances the expression of MHC class II, CD54, CD86, and CD23 on human B cells in vitro. CP-870,893 also enhances dendritic cell activity as evidenced by cytokine secretion (IL-12, IL-23, IL-8), the upregulation of CD86 and CD83, and the ability to prime T cells to secrete IFNγ. In SCID-beige mice, a single parenteral injection of CP-870,893 was therapeutically effective against several CD40(pos) human tumors (B-cell lymphoma, breast, colon, and prostate) indicating direct effects on tumor cell survival and/or growth. When mice were co-implanted with human T cells and dendritic cells, the activity of CP-870,893 against CD40(pos) tumors increased, and efficacy was also observed against CD40(neg) and CD40(low) tumors demonstrating the ability of CP-870,893 to enhance anti-tumor immune function in vivo. These studies suggest that CP-870,893 has the potential to be efficacious against a wide range of tumor types through both direct and immune-mediated effects.

The CD40-CD154 interaction would correlate with proliferation and immune escape in pancreatic ductal adenocarcinoma

BACKGROUND

CD40 and CD154 are associated with lymphocyte signaling pathways and they are also expressed in some malignant neoplasms, but the significance in pancreatic cancer is unknown.

METHODS

Eighty pancreatic cancer specimens were stained immunohistochemically, and the results were correlated with the patients' clinicopathologic features. Subsequently, in vitro analysis of CD40-CD154 signaling was performed.

RESULT

Immunohistochemical analysis of tumor cells showed that 29 patients (36.3%) were positive for CD40, and 17 patients (21.3%) had very high CD154 expression. The survival of patients who had very high CD154 expression was significantly better than that of others (P = 0.0198). Univariate and multivariate analysis revealed that very high CD154 expression in cancer cells was not an independent, favorable prognostic factor (risk ratio, 0.493; P = 0.0224). On in vitro proliferation assay, the growth of PK-45P and KP-4 cells was blocked by CD40 and CD154 blocking antibodies. Moreover, on in vitro cytokine assay, Th-2 cytokines from PK-45P and SUIT-2 were blocked by CD40 or CD154 blocking antibody.

CONCLUSION

These results suggest that the CD40-CD154 interaction would correlate with cell proliferation and secretion of cytokines in PDAC cells, and CD154 overexpression could be a favorable prognostic factor in PDAC patients.

An atypical E3 ligase zinc finger protein 91 stabilizes and activates NF-kappaB-inducing kinase via Lys63-linked ubiquitination

The NF-κB transcription factors control many physiological processes, including inflammation, immunity, and apoptosis. Its activity contributes to the development of various cell malignancies. NF-κB-inducing kinase (NIK) plays a pivotal role in NF-κB activation. However, the molecular mechanism to stabilize and activate NIK remains elusive, although it is known that cIAP1/2 (cellular inhibitor of apoptosis 1 and 2) ubiquitinate NIK for degradation. Here, we report a novel NF-κB-related zinc finger protein 91 (ZFP91) that stabilizes and activates NIK in a ubiquitination-dependent manner. We show that ZFP91 interacts with and promotes the Lys(63)-linked ubiquitination of NIK and subsequent processing of p100 to p52. The results of in vitro biochemical assays indicate that ZFP91 functions as an E3 ligase directly to NIK. Remarkably, the ubiquitination of NIK coincides with its Thr(559) phosphorylation. Furthermore, knockdown of ZFP91 expression by RNA interference inhibits the CD40 ligation-induced activation of NIK and p100 processing as well as the expression of noncanonical NF-κB target genes. These data clearly indicate that ZFP91 is an important regulator of the noncanonical NF-κB pathway.

Direct inhibition of elastase activity by indole-3-carbinol triggers a CD40-TRAF regulatory cascade that disrupts NF-kappaB transcriptional activity in human breast cancer cells

Treatment of highly tumorigenic MDA-MB-231 human breast cancer cells with indole-3-carbinol (I3C) directly inhibited the extracellular elastase-dependent cleavage of membrane-associated CD40, a member of the tumor necrosis factor (TNF) receptor superfamily. CD40 signaling has been implicated in regulating cell survival, apoptosis, and proliferation, as well as in sensitizing breast cancer cells to chemotherapy, and is therefore an important potential target of novel breast cancer treatments. The I3C-dependent accumulation of full-length unprocessed CD40 protein caused a shift in CD40 signaling through TNF receptor-associated factors (TRAF), including the TRAF1/TRAF2 positive regulators and TRAF3 negative regulator of NF-kappaB transcription factor activity. Because TRAF1 is a transcriptional target gene of NF-kappaB, I3C disrupted a positive feedback loop involving these critical cell survival components. siRNA ablation of elastase expression mimicked the I3C inhibition of CD40 protein processing and G(1) cell cycle arrest, whereas siRNA knockdown of TRAF3 and the NF-kappaB inhibitor IkappaB prevented the I3C-induced cell cycle arrest. In contrast, siRNA knockdown of PTEN had no effect on the I3C control of NF-kappaB activity, showing the importance of CD40 signaling in regulating this transcription factor. Our study provides the first direct in vitro evidence that I3C directly inhibits the elastase-mediated proteolytic processing of CD40, which alters downstream signaling to disrupt NF-kappaB-induced cell survival and proliferative responses. Furthermore, we have established a new I3C-mediated antiproliferative cascade that has significant therapeutic potential for treatment of human cancers associated with high levels of elastase and its CD40 membrane substrate.

Killer dendritic cells and their potential for cancer immunotherapy

Known for years as the principal messengers of the immune system, dendritic cells (DC) represent a heterogeneous population of antigen presenting cells critically located at the nexus between innate and adaptive immunity. DC play a central role in the initiation of tumor-specific immune responses as they are endowed with the unique ability to take up, process and present tumor antigens to naïve CD4(+) or CD8(+) effector T lymphocytes. By virtue of the cytokines they produce, DC also regulate the type, strength and duration of T cell immune responses. In addition, they can participate in anti-tumoral NK and NKT cell activation and in the orchestration of humoral immunity. More recent studies have documented that besides their primary role in the induction and regulation of adaptive anti-tumoral immune responses, DC are also endowed with the capacity to directly kill cancer cells. This dual role of DC as killers and messengers may have important implications for tumor immunotherapy. First, the direct killing of malignant cells by DC may foster the release and thereby the immediate availability of specific tumor antigens for presentation to cytotoxic or helper T lymphocytes. Second, DC may participate in the effector phase of the immune response, potentially augmenting the diversity of the killing mechanisms leading to tumor elimination. This review focuses on this non-conventional cytotoxic function of DC as it relates to the promotion of cancer immunity and discusses the potential application of killer DC (KDC) in tumor immunotherapy.

Anti-CD40 monoclonal antibody

Normal, bi-directional interactions between CD 40 and its natural ligand CD 154 (CD 40 ligand) are central to the generation of both T cell-dependent, humoral immune responses and cytotoxic T-cell responses. CD 40 is expressed on a broad range of hematological and epithelial malignancies. The development of monoclonal antibodies directed against CD 40 allows effective targeting of malignant cells through multiple mechanisms that include the recruitment of immune effector mechanisms such as complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity, direct anti-proliferative effects on neoplastic cells and, importantly, by the activation of tumor-targeted cellular cytotoxicity. This review provides the background to the early clinical trial data that are now beginning to emerge for this potentially exciting new treatment approach.

The Janus faces of CD40 in cancer

CD40 is a TNF receptor family member that is widely recognized for its prominent role in immune regulation and homeostasis. Expression of CD40 is not restricted to normal lymphoid cells but is also evident in the majority of haemopoietic and epithelial malignancies where it has been implicated in oncogenic events. Accumulating evidence, however, suggests that the CD40 pathway can be exploited for cancer therapy by virtue of its ability to stimulate the host anti-tumor immune response, normalize the tumor microenvironment and directly suppress the growth of CD40-positive tumors. Here, we provide an overview of the multifaceted functions of the CD40 pathway in cancer and its emerging role in the treatment of malignancy.

Molecular mechanism and function of CD40/CD40L engagement in the immune system

SUMMARY

During the generation of a successful adaptive immune response, multiple molecular signals are required. A primary signal is the binding of cognate antigen to an antigen receptor expressed by T and B lymphocytes. Multiple secondary signals involve the engagement of costimulatory molecules expressed by T and B lymphocytes with their respective ligands. Because of its essential role in immunity, one of the best characterized of the costimulatory molecules is the receptor CD40. This receptor, a member of the tumor necrosis factor receptor family, is expressed by B cells, professional antigen-presenting cells, as well as non-immune cells and tumors. CD40 binds its ligand CD40L, which is transiently expressed on T cells and other non-immune cells under inflammatory conditions. A wide spectrum of molecular and cellular processes is regulated by CD40 engagement including the initiation and progression of cellular and humoral adaptive immunity. In this review, we describe the downstream signaling pathways initiated by CD40 and overview how CD40 engagement or antagonism modulates humoral and cellular immunity. Lastly, we discuss the role of CD40 as a target in harnessing anti-tumor immunity. This review underscores the essential role CD40 plays in adaptive immunity.

Adenovirus delivery of human CD40 ligand gene confers direct therapeutic effects on carcinomas

CD40, a tumor necrosis factor receptor family member, is an emerging target for cancer therapy being best appreciated as an important regulator of the anti-tumor immune response. In this study, we report the development of a replication-defective recombinant adenovirus (RAd) vector expressing human CD40 ligand (RAd-hCD40L) and show that sustained engagement of the CD40 pathway in malignant cells results in direct anti-proliferative and pro-apoptotic effects. Thus, transduction of CD40-positive bladder, cervical and ovarian carcinoma cell lines with RAd-hCD40L potently inhibits their proliferation in vitro, whereas CD40-negative lines remain unresponsive. RAd-hCD40L is also found to be superior to recombinant CD40L in inducing carcinoma cell death and in amplifying the cytotoxic effects of the chemotherapeutic agents 5-fluorouracil, cis-platin and mitomycin C. Soluble CD40L is produced by RAd-hCD40L transduced carcinoma cells but unlike other soluble tumor necrosis factor family ligands, it does not interfere with the death-promoting activity of its membrane-bound form. In a mouse xenograft tumor model bearing a human bladder carcinoma, intratumoral delivery of RAd-hCD40L suppresses cancer growth. These findings highlight the potential of exploiting the CD40 pathway in carcinomas using CD40L gene transfer alone or in combination with other modalities for cancer therapy. Our results have also broader implications in understanding the multifaceted anti-tumor activities of the CD40 pathway in carcinomas, which thus offer an attractive option for future clinical application.

Up-regulation of the expression of costimulatory molecule CD40 in hepatocytes by hepatitis B virus X antigen

Hepatitis B virus (HBV) is a major causative agent of hepatocellular carcinoma (HCC) but the pathogenesis remains poorly understood. To provide novel insights into the pathogenesis of HBV, we examined the expression profile of HBV-positive HepG2.2.15 and -negative HepG2 cells. Genes that were markedly up- or down-regulated in the presence of HBV are involved in signal transduction, apoptosis, transcriptional regulation, protein degradation and oncogenesis. Among the analyzed co-signaling molecules CD40, CD80, CD86, B7-H1, B7-DC, OX40, and B7RP-1, CD40 was the only one up-regulated. Following establishment of stable HepG2 cell lines transfected with HBV genes, we found that HBxAg up-regulated the expression of CD40. We also found that CD40 activation by CD40L could promote the expression of negative co-signaling molecule B7-H1, rather than induce the apoptosis of HepG2HBx cell as expected. These results suggest that CD40 up-regulation by HBxAg may play a facilitating role in the pathogenesis causing HCC.

Therapeutic interventions targeting CD40L (CD154) and CD40: the opportunities and challenges

CD40 was originally identified as a receptor on B-cells that delivers contact-dependent T helper signals to B-cells through interaction with CD40 ligand (CD40L, CD154). The pivotal role played by CD40-CD40L interaction is illustrated by the defects in B-lineage cell development and the altered structures of secondary lymphoid tissues in patients and engineered mice deficient in CD40 or CD40L. CD40 signaling also provides critical functions in stimulating antigen presentation, priming of helper and cytotoxic T-cells and a variety of inflammatory reactions. As such, dysregulations in the CD40-CD40L costimulation pathway are prominently featured in human diseases ranging from inflammatory conditions to systemic autoimmunity and tissue-specific autoimmune diseases. Moreover, studies in CD40-expressing cancers have provided convincing evidence that the CD40-CD40L pathway regulates survival of neoplastic cells as well as presentation of tumor-associated antigens to the immune system. Extensive research has been devoted to explore CD40 and CD40L as drug targets. A number of anti-CD40L and anti-CD40 antibodies with diverse biological effects are in clinical development for treatment of cancer and autoimmune diseases. This chapter reviews the role of CD40-CD40L costimulation in disease pathogenesis, the characteristics of therapeutic agents targeting this pathway and status of their clinical development.

Incorporation of CD40 ligand into the envelope of pseudotyped single-cycle Simian immunodeficiency viruses enhances immunogenicity

A vaccine for the prevention of human immunodeficiency virus (HIV) infection is desperately needed to control the AIDS pandemic. To address this problem, we developed vesicular stomatitis virus glycoprotein-pseudotyped replication-defective simian immunodeficiency viruses (dSIVs) as an AIDS vaccine strategy. The dSIVs retain characteristics of a live attenuated virus without the drawbacks of potential virulence caused by replicating virus. To improve vaccine immunogenicity, we incorporated CD40 ligand (CD40L) into the dSIV envelope. CD40L is one of the most potent stimuli for dendritic cell (DC) maturation and activation. Binding of CD40L to its receptor upregulates expression of major histocompatibility complex class I, class II, and costimulatory molecules on DCs and increases production of proinflammatory cytokines and chemokines, especially interleukin 12 (IL-12). This cytokine polarizes CD4(+) T cells to Th1-type immune responses. DC activation and mixed lymphocyte reaction (MLR) studies were performed to evaluate the immunogenicity of CD40L-dSIV in vitro. Expression levels of CD80, CD86, HLA-DR, and CD54 on DCs transduced with the dSIV incorporating CD40L (CD40L-dSIV) were significantly higher than on those transduced with dSIV. Moreover, CD40L-dSIV-transduced DCs expressed up to 10-fold more IL-12 than dSIV-transduced DCs. CD40L-dSIV-transduced DCs enhanced proliferation and gamma interferon secretion by naive T cells in an MLR. In addition, CD40L-dSIV-immunized mice exhibited stronger humoral and cell-mediated immune responses than dSIV-vaccinated animals. The results show that incorporating CD40L into the dSIV envelope significantly enhances immunogenicity. As a result, CD40L-dSIVs can be strong candidates for development of a safe and highly immunogenic AIDS vaccine.

CD4+T cells in CIKs (CD4+ CIKs) reversed resistance to fas-mediated apoptosis through CD40/CD40L ligation rather than IFN-gamma stimulation

BACKGROUND

Cytokine-induced killer cells (CIKs) are nonspecific antitumor effectors with superior advantages. CD4+ CIKs can induce Fas-dependent apoptosis in sensitive Raji cells. Here, a Fas-dependent apoptosis was detected in resistant breast cancer MDA-MB-231 cells, and underlying mechanisms were discriminated.

METHODS

Amplification of CIKs and purification of CD4+ CIKs were performed in 15 patients with malignant solid tumors. The expression of CD40L and soluble cytokines in CD4+ CIKs were analyzed. The apoptotic rates of tumor cells and the expression of Fas on membranes were detected using flow cytometry assay. The specific blocking antibodies against FasL, CD40L, and interferon-gamma (IFN-gamma) were added to abolish their effects. The changes of 4 apoptosis-related genes (Bcl-2, Bax, Fas-associating protein with death domain [FADD], and FLICE inhibitory protein [c-FLIP]) in MDA-MB-231 cells cocultured with CD4+ CIKs were measured by real-time quantitative reverse-transcriptase polymerase chain reaction after 6 hours and 24 hours with or without blocking antibodies.

RESULTS

Upregulated expression of membrane-attached CD40L and dramatically increased secretion of soluble CD40L and IFN-gamma were identified in CD4+ CIK. The susceptibility to Fas-mediated apoptosis of insensitive MDA-MB-231 cells was elevated after being pretreated with supernatants from CD4+ CIK. After coculture with CD4+ CIK, apoptosis in MDA-MB-231 cells paralleled with enhanced expression of Fas was blocked fully by either anti-FasL or anti-CD40L, but only partly by anti-IFN-gamma antibodies. The anti-CD40L monoclonal antibody (McAb) rather than anti-IFN-gamma McAb induced significant increase of c-FLIP, which negatively correlated with the apoptosis observed in MDA-MB-231 cells.

CONCLUSIONS

Apoptosis in MDA-MB-231 cells induced by CD4+ CIK is Fas-dependent. The reversion of Fas resistance is mediated through CD40/CD40L ligation rather than IFN-gamma stimulation by inhibiting synthesis of c-FLIP.

CD40 ligation in vivo can induce T cell independent antitumor effects even against immunogenic tumors

Antitumor effects of CD40 ligation appear to involve distinct antitumor effector cells in different experimental models. In this study, we tested whether T cells were required for antitumor effects of agonistic anti-CD40 mAb (alphaCD40) against immunogenic versus poorly immunogenic tumors. Treatment of mice bearing poorly immunogenic B16 melanoma and its more immunogenic variant, B16-hsp72.1, with alphaCD40 resulted in a similar level of tumor growth suppression. Depletion of T cells did not reduce the antitumor effects in these 2 tumor models. To generate antitumor T cell responses, C57BL/6 mice were immunized with irradiated B16-hsp72.1. Treatment of these vaccinated mice challenged with a high dose of B16-hsp72.1 tumor cells with alphaCD40 induced tumor growth suppression, which was reduced by T-cell depletion, demonstrating that T cells were involved in the antitumor effect of alphaCD40. However, immunized mice depleted of T cells and treated with alphaCD40 were still able to suppress tumor growth as compared to tumor growth in immunized, T cell-depleted mice not treated with alphaCD40, suggesting that T cells were not required for the antitumor effect of alphaCD40. To confirm a lack of correlation between tumor immunogenicity and T-cell requirement in antitumor effects of CD40 ligation, we found that alphaCD40 induced tumor growth suppression in nude and SCID/beige mice bearing highly immunogenic tumors such as Meth A sarcoma, suggesting that macrophages may play a role. Indeed, both poorly immunogenic and highly immunogenic tumors were sensitive to in vitro growth inhibition by macrophages from alphaCD40-treated mice. Taken together, our results indicate that antitumor effects induced by alphaCD40, even against immunogenic tumors, can be observed in the absence of T cells and may involve macrophages.

CD40-mediated death and cytokine secretion in colorectal cancer: a potential target for inflammatory tumour cell killing

CD40, a member of the tumour necrosis factor family, is expressed in a variety of epithelial cells. Although soluble CD40 agonists are growth-inhibitory, membrane-presented CD40 ligand (CD40L) induces extensive apoptosis in carcinoma cells. This study investigated whether CD40 is expressed in human colorectal carcinoma (CRC) cells and explored the functional consequences of CD40 ligation. CD40 expression in a panel of CRC lines was assessed by flow cytometry and in resected human CRCs by immunohistochemistry. CRC cells were treated in vitro with soluble CD40 agonists or cocultured with fibroblasts expressing membrane-bound CD40 ligand. Apoptosis was determined by flow cytometry using Annexin V/propidium iodide labelling and by a DNA fragmentation assay. Cytokine secretion induced by CD40 ligation was quantified by a multiplex-bead array approach. We show that CD40 is expressed in a proportion of established CRC lines in culture and that receptor expression is functional. Activation of CD40 by membrane-presented CD40L, but not soluble agonists, causes high levels of death in CD40-positive CRC cells and induces secretion of proinflammatory cytokines. In agreement with our in vitro observations, immunohistochemical studies demonstrated that CD40 is highly expressed in a proportion of colorectal cancer specimens. The high level of susceptibility of CRC cells to CD40-killing combined with the ability of CD40 to induce concomitant secretion of proinflammatory cytokines suggest that CD40 ligation may represent a novel mechanism for elimination of CRC cells and render CD40 a promising therapeutic target for the eradication of colorectal tumours.

Effects of CD40 binding on ovarian carcinoma cell growth and cytokine production in vitro

The poor prognosis associated with ovarian carcinoma (OVCA) is linked to the high incidence of local recurrence. There is a pressing need to identify factors that can play a role in OVCA growth and spread. Here, we focused on CD40, a member of the tumour necrosis factor (TNF) receptor superfamily with important functions in immune response. The expression of CD40 has been reported on various types of carcinoma cells, but its biological role is still poorly understood. The aim of the present study was to investigate the expression and function of the CD40 in OVCA cell lines. Detectable CD40 levels ranging from low to very high were found on the cell surface of several OVCA cell lines by flow cytometry analysis. Co-culture with a murine cell line transfected with CD40 ligand (CD40L) inhibited cell growth and up-regulated the secretion of proinflammatory cytokines interleukin (IL)-6, IL-8 and TNF-alpha in high-level CD40-expressing OVCA cell lines. Similarly, an increase of IL-6 and IL-8 release could be obtained by adding a soluble form of CD40L to the OVCA cultures. These results suggest that CD40-CD40L interaction is an important pathway affecting growth regulation and cytokine production in OVCA.