CD40 expression in bladder cancer

CD40 stimulation via CD40 ligand enhances adenovirus-mediated tumour immunogenicity including 'find-me', 'eat-me', and 'kill-me' signalling

Immunostimulatory gene therapy using oncolytic viruses is currently evaluated as a promising therapy for cancer aiming to induce anti-tumour immunity. Here, we investigate the capacity of oncolytic adenoviruses (LOAd) and their transgenes to induce immunogenicity in the infected tumour cells. Oncolysis and death-related markers were assessed after infection of eight human solid cancer cell lines with different LOAd viruses expressing a trimerized, membrane-bound (TMZ)-CD40L, TMZ-CD40L and 41BBL, or no transgenes. The viruses induced transgene expression post infection before they were killed by oncolysis. Death receptors TRAIL-R1, TRAIL-R2 and Fas as well as immunogenic cell death marker calreticulin were upregulated in cell lines post infection. Similarly, caspase 3/7 activity was increased in most cell lines. Interestingly, in CD40+ cell lines there was a significant effect of the TMZ-CD40L-encoding viruses indicating activation of the CD40-mediated apoptosis pathway. Further, these cell lines showed a significant increase of calreticulin, and TRAIL receptor 1 and 2 post infection. However, LOAd viruses induced PD-L1 upregulation which may hamper anti-tumour immune responses. In conclusion, LOAd infection increased the immunogenicity of infected tumour cells and this was potentiated by CD40 stimulation. Due to the simultaneous PD-L1 increase, LOAd viruses may benefit from combination with antibodies blocking PD1/PD-L1.

Perspective view of allogeneic IgG tumor immunotherapy

Allogeneic tumors are eradicated by host immunity; however, it is unknown how it is initiated until the report in Nature by Yaron Carmi et al. in 2015. Currently, we know that allogeneic tumors are eradicated by allogeneic IgG via dendritic cells. AlloIgG combined with the dendritic cell stimuli tumor necrosis factor alpha and CD40L induced tumor eradication via the reported and our proposed potential signaling pathways. AlloIgG triggers systematic immune responses targeting multiple antigens, which is proposed to overcome current immunotherapy limitations. The promising perspectives of alloIgG immunotherapy would have advanced from mouse models to clinical trials; however, there are only 6 published articles thus far. Therefore, we hope this perspective view will provide an initiative to promote future discussion.

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.

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.

IL-15 synergizes with CD40 agonist antibodies to induce durable immunity against bladder cancer

CD40 is a central co-stimulatory receptor implicated in the development of productive anti-tumor immune responses across multiple cancers, including bladder cancer. Despite strong preclinical rationale, systemic administration of therapeutic agonistic antibodies targeting the CD40 pathway have demonstrated dose limiting toxicities with minimal clinical activity to date, emphasizing an important need for optimized CD40-targeted approaches, including rational combination therapy strategies. Here, we describe an important role for the endogenous IL-15 pathway in contributing to the therapeutic activity of CD40 agonism in orthotopic bladder tumors, with upregulation of trans-presented IL-15/IL-15Rα surface complexes, particularly by cross-presenting cDC1s, and associated enrichment of activated CD8 T cells within the bladder tumor microenvironment. In bladder cancer patient samples, we identify DCs as the primary source of IL-15, however, they lack high levels of IL-15Rα at baseline. Using humanized immunocompetent orthotopic bladder tumor models, we demonstrate the ability to therapeutically augment this interaction through combined treatment with anti-CD40 agonist antibodies and exogenous IL-15, including the fully-human Fc-optimized antibody 2141-V11 currently in clinical development for the treatment of bladder cancer. Combination therapy enhances the crosstalk between Batf3-dependent cDC1s and CD8 T cells, driving robust primary anti-tumor activity and further stimulating long-term systemic anti-tumor memory responses associated with circulating memory-phenotype T and NK cell populations. Collectively, these data reveal an important role for IL-15 in mediating anti-tumor CD40 agonist responses in bladder cancer and provide key proof-of-concept for combined use of Fc-optimized anti-CD40 agonist antibodies and agents targeting the IL-15 pathway. These data support expansion of ongoing clinical studies evaluating anti-CD40 agonist antibodies and IL-15-based approaches to evaluate combinations of these promising therapeutics for the treatment of patients with bladder cancer.

Dendritic cell targeting with Fc-enhanced CD40 antibody agonists induces durable antitumor immunity in humanized mouse models of bladder cancer

Intravesical immunotherapy using Bacille Calmette-Guérin (BCG) attenuated bacteria delivered transurethrally to the bladder has been the standard of care for patients with high-risk non-muscle-invasive bladder cancer (NMIBC) for several decades. BCG therapy continues to be limited by high rates of disease recurrence and progression, and patients with BCG-unresponsive disease have few effective salvage therapy options besides radical cystectomy, highlighting a need for new therapies. We report that the immune-stimulatory receptor CD40 is highly expressed on dendritic cells (DCs) within the bladder tumor microenvironment of orthotopic bladder cancer mouse models, recapitulating CD40 expression by DCs found in human disease. We demonstrate that local CD40 agonism in mice with orthotopic bladder cancer through intravesical delivery of anti-CD40 agonist antibodies drives potent antitumor immunity and induces pharmacodynamic effects in the bladder tumor microenvironment, including a reduction in CD8⁺ T cells with an exhausted phenotype. We further show that type 1 conventional DCs (cDC1) and CD8⁺ T cells are required for both bladder cancer immune surveillance and anti-CD40 agonist antibody responses. Using orthotopic murine models humanized for CD40 and Fcγ receptors, we demonstrate that intravesical treatment with a fully human, Fc-enhanced anti-CD40 agonist antibody (2141-V11) induces robust antitumor activity in both treatment-naïve and treatment-refractory settings, driving long-term systemic antitumor immunity with no evidence of systemic toxicity. These findings support targeting CD40-expressing DCs in the bladder cancer microenvironment through an intravesical agonistic antibody approach for the treatment of NMIBC.

LAPTM5-CD40 Crosstalk in Glioblastoma Invasion and Temozolomide Resistance

Background: Glioma therapy is challenged by the diffuse and invasive growth of glioma. Lysosomal protein transmembrane 5 (LAPTM5) was identified as an invasion inhibitor by an in vivo screen for invasion-associated genes. The aim of this study was to decipher the function of LAPTM5 in glioblastoma and its interaction with the CD40 receptor which is intensively evaluated as a target in the therapy of diverse cancers including glioma.

Methods: Knockdown of LAPTM5 was performed in different glioma cell lines to analyze the impact on clonogenicity, invasiveness, sensitivity to temozolomide chemotherapy, and tumorigenicity in vitro and in vivo. An expression array was used to elucidate the underlying pathways. CD40 knockdown and overexpression were induced to investigate a potential crosstalk of LAPTM5 and CD40. LAPTM5 and CD40 were correlated with the clinical outcome of glioma patients.

Results: Knockdown of LAPTM5 unleashed CD40-mediated NFκB activation, resulting in enhanced invasiveness, clonogenicity, and temozolomide resistance that was overcome by NFκB inhibition. LAPTM5 expression correlated with better overall survival in glioblastoma patients depending on CD40 expression status.

Conclusion: We conclude that LAPTM5 conveyed tumor suppression and temozolomide sensitation in CD40-positive glioblastoma through the inhibition of CD40-mediated NFκB activation. Hence, LAPTM5 may provide a potential biomarker for sensitivity to temozolomide in CD40-positive glioblastoma.

Induction of NKG2D ligand expression on tumor cells by CD8+ T-cell engagement-mediated activation of nuclear factor-kappa B and p300/CBP-associated factor

The ligands for the natural killer group 2 (NKG2D) protein render tumor cells susceptible to NKG2D-dependent immune cell attack. However, cancer cells escape from immune surveillance by downregulating NKG2D ligands. We previously discovered that engagement of activated CD8+ T cells and tumor cells induces NKG2D ligands on tumor cells, but the underlying mechanism remains to be defined. Both in vivo mouse tumor models and in vitro cell assays were performed to study the downstream signaling. Our results supported the notion that, upon engagement with the cognate receptors, CD137 ligand and CD40 initiates activation of nuclear factor-kappa B (NF-κB) signaling in tumor cells even in the absence of CD8+ T cells. Like tumor and CD8+ T cell contact-dependent NKG2D ligand induction, this CD137L/CD40-mediated signaling activation was associated with elevated levels of acetyltransferase P300/CBP-associated factor (PCAF), whereas inhibition of phosphorylated NF-κB abrogated PCAF induction. Although stimulation of CD137L/CD40-mediated signaling is vital, inflammatory cytokines, including interferon gamma (IFNγ) and TNFα, also facilitate NKG2D ligand-induced immune surveillance via both facilitating T-cell chemotaxis and CD137L/CD40 induced NF-κB/PCAF activation. Collectively, our results unveil a novel mechanism of NKG2D ligand upregulation involving reverse signaling of CD40 and CD137L on tumor cells which, along with inflammatory cytokines IFNγ and TNFα, stimulate downstream NF-κB and PCAF activation. Understanding this mechanism may help in development of induced NKG2D ligand-dependent T-cell therapy against cancers.

New emerging targets in cancer immunotherapy: the role of Cluster of Differentiation 40 (CD40/TNFR5)

Cluster of differentiation 40 (CD40) is a member of the tumour necrosis factor family and a new immune-modulating target in cancer treatment. B cells, myeloid cells and dendritic cells can express CD40 and mediate via the ligand cluster of differentiation 40 ligand (CD40L) cytotoxic T cell priming under physiological conditions. Therapeutically, recombinant CD40L molecules, intratumour application of adenoviral vectors leading to CD40L expression and agonistic monoclonal CD40 antibodies are currently tested in various cancer entities for their immune-modulating potential. Early clinical trials suggest safety for agonistic CD40 antibodies with encouraging antitumour effects. Adverse events encompass cytokine release storm, hepatoxicity, thromboembolic events and were so far reported to be clinically manageable and transient. Ongoing studies investigate CD40 activation in combination with chemotherapy, radiation, targeted therapies and immunomodulatory agents. Further studies are awaited to specifically identify patients with the greatest clinical benefit based on predictive biomarkers.

Expression of Immune System-Related Membrane Receptors CD40, RANK, BAFFR and LTβR is Associated with Clinical Outcome of Operated Non-Small-Cell Lung Cancer Patients

An increasing number of studies implicates the NF-κB (Nuclear Factor of kappa light chain gene enhancer in B cells) alternative pathway in non-small-cell lung cancer (NSCLC). We assessed the clinical significance of CD40 (Tumor necrosis factor receptor superfamily member 5, TNFRSF5), BAFFR (B-cell activating factor receptor), RANK (Receptor activator of NF-κB) and LTβR (lymphotoxin β receptor) receptors, which activate the alternative pathway of NF-κB, in NSCLC. Evaluation of CD40, BAFFR, RANK and LTβR expression was performed based on the Cancer Genome Atlas (TCGA) and the Genotype-Tissue Expression (GTEx) datasets, while protein expression was assessed by immunohistochemistry in specimens from 119 operated NSCLC patients. CD40 gene overexpression was correlated with improved five-year overall survival (OS) (p < 0.001), while increased BAFFR and LTβR mRNA levels were associated with worse OS in patients with adenocarcinomas (p < 0.001 and p < 0.001, respectively). Similarly, patients with adenocarcinomas exhibited a negative correlation between membranous BAFFR protein expression in carcinoma cells and three- and five-year survival (p = 0.021; HR, 4.977 and p = 0.030; HR, 3.358, respectively) as well as between BAFFR protein overexpression in cancer-associated fibroblasts (CAFs) and two-year survival (p = 0.036; HR, 1.983). Patients with increased LTβR nuclear protein staining or stage II patients with lower cytoplasmic LTβR protein expression had worse five-year OS (p = 0.039 and p = 0.008, respectively). Moreover, CD40 protein expression in tumor infiltrating lymphocytes (TILs) and CAFs was positively associated with metastatic spread while BAFFR protein expression in CAFs was negatively associated with bone metastasis (p = 0.041). Our data suggests that CD40, BAFFR, RANK and LTβR play an important role in NSCLC and further supports the role of NF-κB alternative pathway in NSCLC.

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.

CD40L inhibits cell growth of THP-1 cells by suppressing the PI3K/Akt pathway

Introduction

Acute myeloid leukemia (AML), the hematological malignant tumor with high mortality, is still difficult to treat. CD40L is a type II transmembrane protein, which has been reported to have the potential to inhibit growth of some cancer cells.

Materials and methods

In order to determine the role of CD40L on AML-M5 cell line THP-1, we overexpressed CD40L in the cells using a lentiviral vector system (pHBLV-CMVIE-Zs Green-T2A-puro vector); overexpression was confirmed by the detection of green fluorescent protein and CD40L protein expression.

Results

Cellular apoptosis, proliferation, and cycle assays showed that CD40L could promote the apoptosis of, suppress the proliferation of, and stimulate the arrest of the G1/S phase of THP-1 cells. Finally, the protein expression of P53, Bax/Bcl-2, cyclinD1, PCNA, PTEN, and p-Akt illustrated that CD40L may partly influence cell growth of THP-1 cells through those genes, which was confirmed by immunohistochemistry and a PI3K/Akt activator.

Conclusion

Taken together, CD40L could inhibit cell growth of THP-1 cells through the PI3K/Akt pathway, indicating that the overexpression of CD40L may be a potential target to treat the AML-M5 disease.

Co-stimulatory and co-inhibitory pathways in cancer immunotherapy

Cancer remains the leading cause of death worldwide. Traditional treatments such as surgery, radiation, and chemotherapy have had limited efficacy, especially with late stage cancers. Cancer immunotherapy and targeted therapy have revolutionized how cancer is treated, especially in patients with late stage disease. In 2013 cancer immunotherapy was named the breakthrough of the year, partially due to the established efficacy of blockade of CTLA-4 and PD-1, both T cell co-inhibitory molecules involved in tumor-induced immunosuppression. Though early trials promised success, toxicity and tolerance to immunotherapy have hindered long-term successes. Optimizing the use of co-stimulatory and co-inhibitory pathways has the potential to increase the effectiveness of T cell-mediated antitumor immune response, leading to increased efficacy of cancer immunotherapy. This review will address major T cell co-stimulatory and co-inhibitory pathways and the role they play in regulating immune responses during cancer development and treatment.

Cytotoxic effect caspase activation dependent of a genetically engineered fusion protein with a CD154 peptide mimetic (OmpC-CD154p) on B-NHL cell lines is mediated by the inhibition of bcl-6 and YY1 through MAPK p38 activation

The interaction between CD40, and its ligand, CD154, is essential for the development of humoral and cellular immune responses. The selective inhibition or activation of this pathway forms the basis for the development of new therapeutics against immunologically based diseases and malignancies. We are developing a gene fusion of Salmonella typhi OmpC protein expressing the CD154 Tyr140-Ser-149 amino acid strand. This OmpC-CD154 binds CD40 and activates B cells. In this study, we demonstrate that OmpC-CD154_p treatment inhibits cell growth, proliferation and induced apoptosis in the B-NHL cell lines Raji and Ramos. The Bcl-2 family proteins were regulated and the Bcl-6 and YY1 oncoproteins were inhibited. p38 MAPK activation is an important mechanism underlying the effect on proliferation and apoptosis mediated by this fusion protein. This study establishes a basis for the possible use of fusion protein OmpC-CD154 as an alternative treatment for B-NHL.

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.

Intratumoral CD40 activation and checkpoint blockade induces T cell-mediated eradication of melanoma in the brain

CD40 agonists bind the CD40 molecule on antigen-presenting cells and activate them to prime tumor-specific CD8⁺ T cell responses. Here, we study the antitumor activity and mechanism of action of a nonreplicating adenovirus encoding a chimeric, membrane-bound CD40 ligand (ISF35). Intratumoral administration of ISF35 in subcutaneous B16 melanomas generates tumor-specific, CD8⁺ T cells that express PD-1 and suppress tumor growth. Combination therapy of ISF35 with systemic anti-PD-1 generates greater antitumor activity than each respective monotherapy. Triple combination of ISF35, anti-PD-1, and anti-CTLA-4 results in complete eradication of injected and noninjected subcutaneous tumors, as well as melanoma tumors in the brain. Therapeutic efficacy is associated with increases in the systemic level of tumor-specific CD8⁺ T cells, and an increased ratio of intratumoral CD8⁺ T cells to CD4⁺ Tregs. These results provide a proof of concept of systemic antitumor activity after intratumoral CD40 triggering with ISF35 in combination with checkpoint blockade for multifocal cancer, including the brain.

Treatment options for metastatic melanoma are limited. Here the authors show that combining an immunostimulant adenovirus, currently in clinical trials for leukemia, with immune checkpoints blockade (ICB) results in systemic eradication of ICB resistant melanoma tumours from both skin and brain of mice.

Emerging role of immunotherapy in urothelial carcinoma-Future directions and novel therapies

Tremendous advances in our understanding of the tumor immunology and molecular biology of urothelial carcinoma (UC) have led to the recent approval of immunotherapy as a novel option for patients with UC with advanced disease. Despite the promising data of novel immune checkpoint inhibitors, only a small subset of patients with UC achieves durable remissions. Because an optimal antitumor response requires coordination of multiple immune, tumor, and microenvironment effector cells, novel approaches targeting distinct mechanisms of action likely in combination are needed. In addition, discovery of reliable immune biomarkers, understanding of mechanisms of resistance, and novel clinical trial designs are warranted for maximum benefit of UC immunotherapy.

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.

T cells and costimulation in cancer

Optimal T cell response is dependent not only on T cell receptor activation, but also on additional signaling from coreceptors. The main coreceptors include B7 and tumor necrosis factor family members. They exert costimulatory or coinhibitory effects, and their balance determines the fate of T cell response. In normal conditions, costimulators facilitate the development of protective immune response, whereas coinhibitors dampen inflammation to avoid organ/tissue damage from excessive immune reaction. In the tumor microenvironment, the balance is garbled: inhibitory pathways predominate, and T cell response is impaired. The importance of cosignaling in the tumor immune response has been experimentally and clinically demonstrated. New therapeutic strategies targeting T cell cosignaling, especially coinhibitory molecules, are under active experimental and clinical investigation. This review summarizes the functions of main T cell cosignaling axes and discusses their clinical application.

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.

Locally delivered CD40 agonist antibody accumulates in secondary lymphoid organs and eradicates experimental disseminated bladder cancer

Immunotherapy with intratumoral injection of adenoviral vectors expressing CD40L has yielded positive results in experimental and clinical bladder cancer. We therefore hypothesized that anti-CD40 antibody would be effective in this setting. Agonistic CD40 antibodies were developed as vaccine adjuvants but have later been used as treatment of advanced solid tumors and hematologic cancers. Systemic anti-CD40 therapy has been associated with immune-related adverse events, such as cytokine release syndrome and liver toxicity, and local delivery is an attractive approach that could reduce toxicity. Herein, we compared local and systemic anti-CD40 antibody delivery to evaluate efficacy, toxicity, and biodistribution in the experimental MB49 bladder cancer model. Antitumor effects were confirmed in the B16 model. In terms of antitumor efficacy, local anti-CD40 antibody stimulation was superior to systemic therapy at an equivalent dose and CD8 T cells were crucial for tumor growth inhibition. Both administration routes were dependent on host CD40 expression for therapeutic efficacy. In vivo biodistribution studies revealed CD40-specific antibody accumulation in the tumor-draining lymph nodes and the spleen, most likely reflecting organs with frequent target antigen-expressing immune cells. Systemic administration led to higher antibody concentrations in the liver and blood compared with local delivery, and was associated with elevated levels of serum haptoglobin. Despite the lack of a slow-release system, local anti-CD40 therapy was dependent on tumor antigen at the injection site for clearance of distant tumors. To summarize, local low-dose administration of anti-CD40 antibody mediates antitumor effects in murine models with reduced toxicity and may represent an attractive treatment alternative in the clinic.

AdCD40L--crossing the valley of death?

CD40-mediated cancer therapy has been under development since it became clear that CD40 plays a profound role in the stimulation of adaptive immune responses. Further, CD40 signaling on tumor cells may lead to growth arrest or even apoptosis that improves therapy outcome. The therapeutic window is appealing since the immune system is selective and normal cells do not apoptose upon CD40 signaling. AdCD40L is an adenoviral-based immunostimulatory gene therapy under evaluation for its efficacy to treat cancer. Because of its nature, the adenoviral backbone will stimulate TLRs while CD40L potentiates the shifts toward Th1 type of immunity. AdCD40L has shown efficacy in various murine models, and safety studies have been performed on dog patients and in human clinical trials. AdCD40L has been used for both ex vivo gene modification of tumor cell vaccines as well as for direct intratumoral injections. Lately, an oncolytic vector has been used to further increase the eradication of solid tumors that as a consequence further boosts the release of tumor antigens and creates danger signaling in the tumor micro milieu. This review discusses the currently unfolding mechanisms of action of AdCD40L gene therapy and its possibilities to reach clinical care.

Pathobiology and chemoprevention of bladder cancer

Our understanding of the pathogenesis of bladder cancer has improved considerably over the past decade. Translating these novel pathobiological discoveries into therapies, prevention, or strategies to manage patients who are suspected to have or who have been diagnosed with bladder cancer is the ultimate goal. In particular, the chemoprevention of bladder cancer development is important, since urothelial cancer frequently recurs, even if the primary cancer is completely removed. The numerous alterations of both oncogenes and tumor suppressor genes that have been implicated in bladder carcinogenesis represent novel targets for therapy and prevention. In addition, knowledge about these genetic alterations will help provide a better understanding of the biological significance of preneoplastic lesions of bladder cancer. Animal models for investigating bladder cancer development and prevention can also be developed based on these alterations. This paper summarizes the results of recent preclinical and clinical chemoprevention studies and discusses screening for bladder cancer.

Recent advances in bacillus Calmette–Guerin immunotherapy in bladder cancer

The concept of using Mycobacterium for cancer treatment goes back to the 19th Century. Today, bacillus Calmette–Guerin (BCG) vaccine is a well-established treatment for human bladder cancer that is arguably superior to intravesical chemotherapy for superficial disease and is commonly used as the first-line adjuvant treatment. Much has been learnt about the effects of BCG on bladder cancer and the immune system, but deeper understanding is required in order to improve its efficacy further, to be able to reliably predict responders and ultimately to adapt this most successful form of cancer immunotherapy for the treatment of other malignancies. This article summarizes the current understanding of BCG cancer immunotherapy mechanisms and discusses possible future developments.

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.

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.

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.

Stimulation through CD40 on Mouse and Human Renal Cell Carcinomas Triggers Cytokine Production, Leukocyte Recruitment, and Antitumor Responses that Can Be Independent of Host CD40 Expression

CD40, a member of the TNFR superfamily, is expressed on a variety of host immune cells, as well as some tumors. In this study, we show that stimulation of CD40 expressed on both mouse and human renal carcinoma cells (RCCs) triggers biological effects in vitro and in vivo. Treatment of the CD40+ Renca mouse RCC tumor cells in vitro with an agonistic anti-CD40 Ab induced strong expression of the genes and proteins for GM-CSF and MCP-1, and induced potent chemotactic activity. Similarly, administration of alphaCD40 to both wild-type and CD40-/- mice bearing Renca tumors resulted in substantial amounts of TNF-alpha and MCP-1 in the serum, increased the number of total splenocytes and MHC class II+ CD11c+ leukocytes, and when combined with IFN-gamma, inhibited the progression of established Renca tumors in vivo in both wild-type and CD40-/- mice. Similarly, treatment of CD40+ A704 and ACHN human RCC lines with mouse anti-human CD40 Ab induced strong expression of genes and proteins for MCP-1, IL-8, and GM-CSF in vitro and in vivo. Finally, in SCID mice, the numbers of ACHN pulmonary metastases were dramatically reduced by treatment with species-specific human CD40 Ab. These results show that CD40 stimulation of CD40+ tumor cells can enhance immune responses and result in antitumor activity.

Constitutive activation of the CD40 pathway promotes cell transformation and neoplastic growth

CD40, a tumour necrosis factor (TNF) receptor family member, is expressed in a variety of cell types, including B lymphocytes, macrophages, fibroblasts, endothelial and epithelial cells, and this widespread expression is likely to account for its central role in normal physiology and disease pathogenesis. In this study, we provide evidence to support a role for constitutive CD40 signalling in cell transformation. We show that the ligand for CD40 (CD40L/CD154) is expressed in CD40-positive human breast tumour biopsies, suggesting that the constitutive activation of the CD40 receptor in vivo may contribute to the oncogenic process. Coexpression of CD40 and CD40L confers oncogenic effects on immortalized human epithelial cells in vitro, increasing their proliferation, motility and invasion. Expression of LMP:CD40, a hybrid molecule comprising the N-terminus and transmembrane domains of the Epstein-Barr virus-encoded latent membrane protein-1 (LMP1) fused to the cytoplasmic tail of CD40, mimics a constitutively active CD40 receptor and promotes the transformation of immortalized rodent fibroblasts in vitro and their oncogenicity in vivo. The observed effects of aberrant CD40 activation on cell transformation are largely diminished upon suppression of the oncogenic NF-kappaB signalling pathway. Taken together, our results suggest a role for the constitutive engagement of the CD40L/CD40/NF-kappaB activation pathway in cell transformation and neoplastic growth. Strategies that neutralize this pathway may therefore be useful in cancer treatment and prevention.

Constitutive expression of functional CD40 on mouse renal cancer cells: induction of Fas and Fas-mediated killing by CD40L

CD40, a member of the TNF receptor superfamily, is expressed on B cells, dendritic cells, and some tumor cells, including melanoma and bladder carcinoma. In this study, we report that both mouse and human renal carcinoma cells (RCC) also constitutively express functional CD40. Treatment of mouse RCC with CD40L induced strong expression of genes and proteins for ICAM-1 and Fas, and this expression was further enhanced by combining CD40L with IFN-gamma. Similar effects were demonstrated using an agonist anti-CD40 antibody. The increased levels of Fas expression on RCC after treatment with CD40L plus IFN-gamma resulted in potent killing by either FasL-positive effector cells or agonistic anti-Fas antibody. The combination of CD40L plus IFN-gamma also significantly enhanced killing of RCC by tumor-specific CTL lines. Our results demonstrate that constitutively expressed CD40 is functionally active and may provide a molecular target for the development of new approaches to the treatment of RCC.

Immunotherapy for superficial bladder cancer

The treatment of superficial bladder cancer requires adjuvant therapies besides transurethral resection because of a high recurrence rate after this standard treatment alone. Current adjuvant therapies involve intravesical chemotherapy for patients at low and intermediate risk for recurrence and progression, and intravesical bacillus Calmette-Guérin for patients at intermediate and high risk. However, these adjuvant therapies fail in a significant number of patients, dictating the need for new and improved adjuvant treatment modalities for superficial bladder cancer. Immunotherapy aiming at the modulation of the immune system of the patient is a promising alternative adjuvant. This review discusses the current status of the clinical development of various immunotherapy approaches for superficial bladder cancer, including passive immunotherapy, immune stimulants, immunogene therapy and cancer vaccination.

Activation of CD40 in Cervical Carcinoma Cells Facilitates CTL Responses and Augments Chemotherapy-Induced Apoptosis

In this study, we describe the expression and function of CD40, a TNF receptor family member, in cervical carcinomas. CD40 was present at very low levels in normal cervical epithelium but was overexpressed in human papillomavirus-infected lesions and advanced squamous carcinomas of the cervix. The stimulation of CD40-positive cervical carcinoma cell lines with soluble CD40L (CD154) resulted in activation of the NF-kappaB and MAPK signaling pathways and up-regulation of cell surface markers and intracellular molecules associated with Ag processing and presentation. Concomitantly, the CD154-induced activation of CD40 in carcinoma cells was found to directly influence susceptibility to CTL-mediated killing. Thus, CD40 stimulation in cervical carcinoma cell lines expressing a TAP-dependent human papillomavirus 16 E6 Ag epitope resulted in their enhanced killing by specific CTLs. However, CD154 treatment of carcinoma cells expressing proteasome-dependent but TAP-independent Ags from the EBV-encoded BRLF1 and BMLF1 failed to increase tumor cell lysis by specific CTLs. Moreover, we demonstrate that chemotherapeutic agents that suppress protein synthesis and reverse the CD40-mediated dissociation of the translational repressor eukaryotic initiation factor 4E-binding protein from the initiation factor eukaryotic initiation factor 4E, such as 5-fluorouracil, etoposide, and quercetin, dramatically increase the susceptibility of cervical carcinoma cells to CD40L-induced apoptosis. Taken together, these observations demonstrate the functional expression of CD40 in epithelial tumors of the cervix and support the clinical exploitation of the CD40 pathway for the treatment of cervical cancer through its multiple effects on tumor cell growth, apoptosis, and immune recognition.

Potential use of CD40 ligand for immunotherapy of childhood B-cell precursor acute lymphoblastic leukaemia

Around 20% of children affected by B-cell precursor acute lymphoblastic leukaemia (BCP-ALL) still experience a recurrence of the disease after diagnosis, despite a significant improvement in the cure rate (80%). Moreover, standard therapies have high and often unacceptable acute and chronic organ toxicity, with an increased risk for secondary malignancies. Therefore, new strategies are needed to improve overall survival and decrease treatment-associated morbidity. Recent in-vitro and in-vivo studies have demonstrated that CD40 engagement improves tumour immunogenicity and, consequently, generates a strong antitumour immune response. The CD40-CD40 ligand (CD40L) system is of pivotal importance in the immune response via interactions between T cells and antigen-presenting cells. The general aim of this chapter is to review the feasibility of developing cellular strategies to increase childhood BCP-ALL immunogenicity, and the potential use of CD40L as a new strategy to induce an antileukaemia immune response in BCP-ALL.

Enhanced levels of CD154 (CD40 ligand) on platelets in patients with chronic heart failure

BACKGROUND

Inflammation plays a significant contributory role in the pathogenesis of chronic heart failure (CHF). Previous data have shown enhanced plasma levels of proinflammatory cytokines, i.e. TNF-alpha and IL-6, as well as a persistent immune activation in patients with CHF. Furthermore, the immune modulator CD154 has been receiving increased attention, since it plays a key role in the pathophysiology of multicellular vascular events such as thrombosis, inflammation and atherosclerosis. Since CD154 initiates and maintains the release of proinflammatory cytokines from endothelial cells, its potential role for the development and progression of CHF is of interest.

METHODS

Fifty patients with CHF (aged 66.9+/-12.6 years, mean ejection fraction 22.1+/-9.2%, NYHA II-IV, 39 of ischemic origin, 11 with idiopathic dilated cardiomyopathy) and 15 healthy controls (aged 62.5+/-9.8 years) were examined. Thirty-two patients were taking aspirin (100 mg/day). Blood was drawn from a peripheral vein and immediately fixed with 1% paraformaldehyde, incubated with anti-CD154, anti-P-selectin, and anti-CD61 and thereafter analyzed by flow cytometry.

RESULTS

Patients with CHF showed significantly enhanced expression of platelet-bound CD154 and P-selectin as compared to controls (CD154: median 35.6 25th percentile: 26.3; 75th percentile: 44.6 vs. 12.8; 25th: 6.8; 75th: 15.6 mean fluorescence intensity [MFI], P<0.001; P-selectin: median 3.2 25th percentile: 1.9; 75th percentile: 5.9 vs. 1.4; 25th: 1.2; 75th: 1.9, MFI, P<0.001). CD154 expression on platelets positively correlated with increasing NYHA-class. In contrast, no significant differences in serum levels of soluble CD154 or CD40 expression on monocytes were detected in the study groups. Antiplatelet-therapy with aspirin did not influence CD154 or P-selectin expression on platelets.

CONCLUSION

Our pilot study demonstrates significantly enhanced levels of CD154 on platelets in patients with CHF. This suggests that the CD40-CD154 axis may contribute to the proinflammatory milieu, which exists in CHF and thus may play a pathogenic role in the development and progression of CHF.

Proapoptotic genes BAX and CD40L are predictors of survival in transitional cell carcinoma of the bladder

The purpose of the study was to investigate the effects of expression of a range of genes involved in apoptosis on outcome in bladder cancer. Immunohistochemistry was used to examine expression of BCL2, BAX, P53, CD40 and CD40L in archival tissues of patients included in various treatment trials for transitional cell carcinoma (TCC) of the bladder. Data were collected on 94 patients who first presented with either invasive or superficial bladder cancer. Median follow-up for alive patients was 83 months (m) (range 12-195 m). Median survival was 80 m (95% CI=56-128 m). Median survivals for the various markers were as follows: BAX-positive patients 110 m vs BAX-negative patients 18 m (P=0.0002); CD40L-positive patients 95 m vs CD40L-negative patients 45 m (P=0.04); BCL2-positive patients 44 m and BCL2-negative patients 74 m, (P=0.64); CD40-positive patients 110 m and CD40 negative patients 45 m (P=0.12); and P53 positive patients 80 m and P53 negative patients 45 m (P=0.58). In conclusion, it was seen that overexpressions of BAX and CD40L are prognostic of better survival in TCC of the bladder. Our results also raise the possibility of the future development of CD40- and CD40 ligand-based immunotherapy for bladder cancer. This study links proapoptotic and antiapoptotic markers to overall survival.