Levels of CD40 expression on dendritic cells dictate tumour growth or regression

Altered Serum Alpha1-Antitrypsin Protease Inhibition before and after Clinical Hematopoietic Stem Cell Transplantation: Association with Risk for Non-Relapse Mortality

α1-Antitrypsin (AAT), an acute-phase reactant not unsimilar to C-reactive protein (CRP), is a serine protease inhibitor that harbors tissue-protective and immunomodulatory attributes. Its concentrations appropriately increase during conditions of extensive tissue injury, and it induces immune tolerance, in part, by inhibiting the enzymatic activity of the inflammatory serine protease, proteinase 3 (PR3). Typically administered to patients with genetic AAT deficiency, AAT treatment was recently shown to improve outcomes in patients with steroid-refractory graft-versus-host disease (GVHD). GVHD represents a grave outcome of allogeneic hematopoietic stem cell transplantation (HSCT), a potentially curative intervention for hematological diseases. The procedure requires radio/chemotherapy conditioning of the prospective marrow recipient, a cytotoxic process that causes vast tissue injury and, in some formats, interferes with liver production of AAT. To date, changes in the functional profile of AAT during allogeneic HSCT, and during the cytotoxic intervention that precedes HSCT, are unknown. The present study followed 53 patients scheduled for allogeneic HSCT (trial registration NCT03188601). Serum samples were tested before and after HSCT for AAT and CRP levels and for intrinsic anti-proteolytic activity. The ex vivo response to clinical-grade AAT was tested on circulating patient leukocytes and on a human epithelial cell line treated with patient sera in a gap closure assay. According to the ex vivo experiments, circulating leukocytes responded to AAT with a favorable immune-regulated profile, and epithelial gap closure was enhanced by AAT in sera from GVHD-free patients but not in sera from patients who developed GVHD. According to serum collected prior to HSCT, non-relapse mortality was reliably predicted by combining three components: AAT and CRP levels and serum anti-proteolytic activity. Taken together, HSCT outcomes are significantly affected by the anti-proteolytic function of circulating AAT, supporting early AAT augmentation therapy for allogeneic HSCT patients.

Tumor targeted delivery of mycobacterial adjuvant encapsulated chitosan nanoparticles showed potential anti-cancer activity and immune cell activation in tumor microenvironment

Targeting immunotherapeutics inside the tumor microenvironment (TME) with intact biological activity remains a pressing issue. Mycobacterium indicus pranii (MIP), an approved adjuvant therapy for leprosy has exhibited promising results in clinical trials of lung (NSCLC) and bladder cancer. Whole MIP as well as its cell wall fraction have shown tumor growth suppression and enhanced survival in mice model of melanoma, when administered peritumorally. Clinically, peritumoral delivery remains a procedural limitation. In this study, a tumor targeted delivery system was designed, where chitosan nanoparticles loaded with MIP adjuvants, when administered intravenously showed preferential accumulation within the TME, exploiting the principle of enhanced permeability and retention effect. Bio-distribution studies revealed their highest concentration inside the tumor after 6 h of administration. Interestingly, MIP adjuvant nano-formulations significantly reduced the tumor volume in the treated groups and increased the frequency of activated immune cells inside the TME. For chemoimmunotherapeutics studies, MIP nano-formulation was combined with standard dosage regimen of Paclitaxel. Combined therapy exhibited a further reduction in tumor volume relative to either of the MIP nano formulations. From this study a three-pronged strategy emerged as the underlying mechanism; chitosan and Paclitaxel have shown direct role in tumor cell death and the MIP nano-formulation activates the tumor residing immune cells which ultimately leads to the reduced tumor growth.

Dendritic Cells: The Long and Evolving Road towards Successful Targetability in Cancer

Dendritic cells (DCs) are a unique myeloid cell lineage that play a central role in the priming of the adaptive immune response. As such, they are an attractive target for immune oncology based therapeutic approaches. However, targeting these cells has proven challenging with many studies proving inconclusive or of no benefit in a clinical trial setting. In this review, we highlight the known and unknown about this rare but powerful immune cell. As technologies have expanded our understanding of the complexity of DC development, subsets and response features, we are now left to apply this knowledge to the design of new therapeutic strategies in cancer. We propose that utilization of these technologies through a multiomics approach will allow for an improved directed targeting of DCs in a clinical trial setting. In addition, the DC research community should consider a consensus on subset nomenclature to distinguish new subsets from functional or phenotypic changes in response to their environment.

Boosting the Immune Response—Combining Local and Immune Therapy for Prostate Cancer Treatment

Due to its slow progression and susceptibility to radical forms of treatment, low-grade PC is associated with high overall survival (OS). With the clinical progression of PC, the therapy is becoming more complex. The immunosuppressive tumor microenvironment (TME) makes PC a difficult target for most immunotherapeutics. Its general immune resistance is established by e.g., immune evasion through Treg cells, synthesis of immunosuppressive mediators, and the defective expression of surface neoantigens. The success of sipuleucel-T in clinical trials initiated several other clinical studies that specifically target the immune escape of tumors and eliminate the immunosuppressive properties of the TME. In the settings of PC treatment, this can be commonly achieved with radiation therapy (RT). In addition, focal therapies usually applied for localized PC, such as high-intensity focused ultrasound (HIFU) therapy, cryotherapy, photodynamic therapy (PDT), and irreversible electroporation (IRE) were shown to boost the anti-cancer response. Nevertheless, the present guidelines restrict their application to the context of a clinical trial or a prospective cohort study. This review explains how RT and focal therapies enhance the immune response. We also provide data supporting the combination of RT and focal treatments with immune therapies.

Berberine mediates tumor cell death by skewing tumor-associated immunosuppressive macrophages to inflammatory macrophages

BACKGROUND

Berberine is a plant-derived alkaloid with potent anti-cancer activities. Berberine may redirect the tumor-promoting immunosuppressive M2 macrophages, to tumoricidal activated M1 macrophages. But such an anti-tumor function remains to be demonstrated.

HYPOTHESIS

Polarization of macrophages to an immunosuppressive phenotype within the tumor microenvironment promotes tumor growth and contributes to resistance to chemotherapy. We examined if berberine would target macrophage polarization to reinstate anti-tumor immune response.

STUDY DESIGN

Using a B16F10 mouse melanoma model, we assessed berberine-induced re-polarization of immunosuppressive M2 macrophages to anti-tumor M1 macrophages and subsequent T-cell activation within the immunosuppressive tumor microenvironment.

METHODS

The B16F10 culture supernatant along with tumor antigen was used as tumor mimicking conditioned medium (CM). The bone marrow-derived macrophages were cultured in CM for 5 days. The CM-induced skewing of macrophages to M2-like phenotype was confirmed by flow cytometry and ELISA. The T-cells were co-cultured with macrophages to decipher the effect of berberine on T-cell differentiation. In vivo efficacy of berberine was analyzed using melanoma model of solid tumor.

RESULTS

Berberine inhibited rIL-6-induced STAT-3 phosphorylation and IL-10 release from B16F10 cells. It enhanced tumor antigen-induced IL-1β, IL-12 and TNFα, but suppressed IL-6 and TGF-β release. Berberine significantly prevented the tumor antigen-mediated IL-10-enhanced IL-6 and TGF-β expression. The CM skewed the bone marrow-derived macrophages to CD206-high but MHC-II-low M2-like tumor-associated macrophages. Berberine partially prevented the generation of these macrophages and was associated with reduced C/EBPβ and Egr2 mRNA expression and lowered IL-10 and TGF-β production. Berberine significantly reduced Arginase-1 expression in CM-treated M1 and M2-like macrophages. Berberine increased MHC-II and CD40 expression on the macrophages augmenting the CTL activity and the number of IFNγ-producing CD4+ T-cells. Berberine significantly lowered tumor volume, weight and enhanced the frequency of M1-like macrophages in mice.

CONCLUSION

These data indicate that berberine interferes with pro-tumor macrophage polarization and IL-10 and TGF-β release but restores Tcell anti-tumor cytotoxicity in the tumor microenvironment.

The application of immune checkpoint blockade in breast cancer and the emerging role of nanoparticle

Breast cancer is the most common malignancy in the female population with a high mortality rate. Despite the satisfying depth of studies evaluating the contributory role of immune checkpoints in this malignancy, few articles have reviewed the pros and cons of immune checkpoint blockades (ICBs). In the current review, we provide an overview of immune-related inhibitory molecules and also discuss the original data obtained from international research laboratories on the aberrant expression of T and non-T cell-associated immune checkpoints in breast cancer. Then, we especially focus on recent studies that utilized ICBs as the treatment strategy in breast cancer and provide their efficiency reports. As there are always costs and benefits, we discuss the limitations and challenges toward ICB therapy such as adverse events and drug resistance. In the last section, we allocate an overview of the recent data concerning the application of nanoparticle systems for cancer immunotherapy and propose that nano-based ICB approaches may overcome the challenges related to ICB therapy in breast cancer. In conclusion, it seems it is time for nanoscience to more rapidly move forward into clinical trials and illuminates the breast cancer treatment area with its potent features for the target delivery of ICBs.

A light way for nuclear cell biologists

The nucleus is a very complex organelle present in eukaryotic cells. Having the crucial task to safeguard, organize and manage the genetic information, it must tightly control its molecular constituents, its shape and its internal architecture at any given time. Despite our vast knowledge of nuclear cell biology, much is yet to be unravelled. For instance, only recently we came to appreciate the existence of a dynamic nuclear cytoskeleton made of actin filaments that regulates processes such as gene expression, DNA repair and nuclear expansion. This suggests further exciting discoveries ahead of us. Modern cell biologists embrace a new methodology relying on precise perturbations of cellular processes that require a reversible, highly spatially confinable, rapid, inexpensive and tunEable external stimulus: light. In this review, we discuss how optogenetics, the state-of-the-art technology that uses genetically encoded light-sensitive proteins to steer biological processes, can be adopted to specifically investigate nuclear cell biology.

The Common Costimulatory and Coinhibitory Signaling Molecules in Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinomas (HNSCCs) are closely linked with immunosuppression, accompanied by complex immune cell functional activities. The abnormal competition between costimulatory and coinhibitory signal molecules plays an important role in the malignant progression of HNSCC. This review will summarize the features of costimulatory molecules (including CD137, OX40 as well as CD40) and coinhibitory molecules (including CTLA-4, PD-1, LAG3, and TIM3), analyze the underlying mechanism behind these molecules' regulation of the progression of HNSCC, and introduce the clinic application. Vaccines, such as those targeting STING while working synergistically with monoclonal antibodies, are also discussed. A deep understanding of the tumor immune landscape will help find new and improved tumor immunotherapy for HNSCC.

Physical activation of innate immunity by spiky particles

Microbial biochemicals have been indicated as the primary stimulators of innate immunity, the first line of the body's defence against infections. However, the influence of topological features on a microbe's surface on immune responses remains largely unknown. Here we demonstrate the ability of TiO₂ microparticles decorated with nanospikes (spiky particles) to activate and amplify the immune response in vitro and in vivo. The nanospikes exert mechanical stress on the cells, which results in potassium efflux and inflammasome activation in macrophages and dendritic cells during phagocytosis. The spiky particles augment antigen-specific humoral and cellular immune responses in the presence of monophosphoryl lipid A and elicit protective immunity against tumour growth and influenza viral infection. The study offers insights into how surface physical cues can tune the activation of innate immunity and provides a basis for engineering particles with increased immunogenicity and adjuvanticity.

Anti-VEGF antibody enhances the antitumor effect of CD40

As its central immunomodulatory effects, CD40 induces interleukin (IL)-12-dependent antitumor immune responses; as its local protumor effects, CD40 induces the expression of vascular endothelial growth factor (VEGF) that promotes tumor angiogenesis and growth. Therefore, using a previously established tumor model in mouse, we examined if the antitumor functions of CD40 are self-limited by VEGF induction. We observed that as the tumor mass grew during day 6 to day 18, VEGF expression in the tumor peaked with concomitant decrease in expressions of CD40 and IL-12 but not of IL-10. Among the angiogenic factors, VEGF-B, VEGFR-1, VEGFR-2, angiopoietin-1 and Tie2 expressions decreased, whereas the expressions of angiopoietin-2 and angiopoietin-3 increased with tumor growth. As significant changes in the expressions of these factors were observed on day 6, we treated the tumor-bearing mice with the agonistic anti-CD40 antibody or neutralizing anti-VEGF antibody-alone or in combination-from the fifth day after the injection of tumor cells. The anti-VEGF antibody significantly enhanced the antitumor effects of the anti-CD40 antibody, as observed through increased survival of the mice, accompanied by reduced angiogenesis and angiopoietin-2 expression but higher T-cell proliferation in response to tumor antigens, increased interferon-γ production and tumor cell cytotoxicity and higher levels of tumor antigen-specific serum IgM, IgG1 and IgG2a, indicating B-cell activation. Thus, our data show for the first time that the combined treatment with an agonistic anti-CD40 antibody and a neutralizing anti-VEGF antibody, which increases antitumor immune response or reduces local angiogenesis, respectively, is a novel antitumor strategy.

CD40 pathway activation reveals dual function for macrophages in human endometrial cancer cell survival and invasion

Reproductive malignancies are a major cause of cancer death in women worldwide. CD40 is a TNF receptor family member, which upon activation may mediate tumor regression. However, despite the great potential of CD40 agonists, their use as a therapeutic option for reproductive cancers has never been investigated. Because CD40 ligation is a potent pathway of macrophage activation, an in vitro model of pro-inflammatory type-1 (Mϕ-1) and anti-inflammatory type-2 (Mϕ-2) macrophages was developed to determine whether and how macrophage CD40 pathway activation might influence endometrial tumor cell behavior. Analysis of tumor growth kinetic in the endometrial cancer xenograft model indicates that, when injected once into the growing tumors, CD40-activated Mϕ-1 greatly reduced, while CD40-activated Mϕ-2 increased tumor size when compared to control isotype-activated Mϕ-1 and Mϕ-2, respectively. In vitro assays indicated that CD40-activated Mϕ-2 increased cell viability but failed to promote cell invasion. CD40-activated Mϕ-1, in contrast, decreased cell survival but greatly increased cell invasion in tumor cells less susceptible to cell death by apoptosis; they also induced the expression of some pro-inflammatory genes, such as IL-6, LIF, and TNF-α, known to be involved in tumor promotion and metastasis. The presence of IFN-γ is minimally required for CD40-activated Mϕ-1 to promote tumor cell invasion, a process that is mediated in part through the activation of the PI3K/Akt2 signaling pathway in tumor cells. From these results, we speculate that some functions of CD40 in tumor-associated Mϕs might limit the therapeutic development of CD40 agonists in endometrial cancer malignancies.

Binding of HIV-1 gp120 to DC-SIGN promotes ASK-1-dependent activation-induced apoptosis of human dendritic cells

During disease progression to AIDS, HIV-1 infected individuals become increasingly immunosuppressed and susceptible to opportunistic infections. It has also been demonstrated that multiple subsets of dendritic cells (DC), including DC-SIGN(+) cells, become significantly depleted in the blood and lymphoid tissues of AIDS patients, which may contribute to the failure in initiating effective host immune responses. The mechanism for DC depletion, however, is unclear. It is also known that vast quantities of viral envelope protein gp120 are shed from maturing HIV-1 virions and form circulating immune complexes in the serum of HIV-1-infected individuals, but the pathological role of gp120 in HIV-1 pathogenesis remains elusive. Here we describe a previously unrecognized mechanism of DC death in chronic HIV-1 infection, in which ligation of DC-SIGN by gp120 sensitizes DC to undergo accelerated apoptosis in response to a variety of activation stimuli. The cultured monocyte-derived DC and also freshly-isolated DC-SIGN(+) blood DC that were exposed to either cross-linked recombinant gp120 or immune-complex gp120 in HIV(+) serum underwent considerable apoptosis after CD40 ligation or exposure to bacterial lipopolysaccharide (LPS) or pro-inflammatory cytokines such as TNFα and IL-1β. Furthermore, circulating DC-SIGN(+) DC that were isolated directly from HIV-1(+) individuals had actually been pre-sensitized by serum gp120 for activation-induced exorbitant apoptosis. In all cases the DC apoptosis was substantially inhibited by DC-SIGN blockade. Finally, we showed that accelerated DC apoptosis was a direct consequence of excessive activation of the pro-apoptotic molecule ASK-1 and transfection of siRNA against ASK-1 significantly prevented the activation-induced excessive DC death. Our study discloses a previously unknown mechanism of immune modulation by envelope protein gp120, provides new insights into HIV immunopathogenesis, and suggests potential therapeutic approaches to prevent DC depletion in chronic HIV infection.

HIV-1 infected individuals become increasingly immunocompromised and susceptible to opportunistic infection during disease progression, which is associated with significant reduction of the dendritic cell number in the peripheral blood or secondary lymphoid tissues. Because dendritic cells are the most powerful antigen-presenting cells, their survival is critical for host defence and inadequate dendritic cell number will fail to induce effective host immune responses. Here we describe a mechanism that may at least partly explain why dendritic cells become significantly depleted in chronic HIV-1 infection. We found that after binding of the HIV-1 envelope protein gp120 to the dendritic cell surface protein DC-SIGN, the subsequent activation by CD40 ligation, or by exposure to bacterial product lipopolysaccharide or pro-inflammatory cytokines such as TNF-α and IL-1β, will lead to overexpression of pro-apoptotic molecule ASK-1, resulting in excessive dendritic cell death. We also confirmed that DC-SIGN(+) dendritic cells in the blood of HIV-1 infected individuals have actually been pre-sensitized by viral gp120, which exists in vast amount in the blood, for activation-induced exorbitant death. Our study thus reveals a previously unknown pathway for dendritic cell depletion and provides clues for potential therapeutic approaches to prevent DC depletion in chronic HIV infection.

A novel role of the scaffolding protein JLP in tuning CD40-induced activation of dendritic cells

Receptor internalization is a common mechanism underlying surface receptor down-regulation (and thus receptor signaling) upon its engagement with the cognate ligand. Tight regulation of surface CD40 expression is critical in regulating different functional properties of dendritic cell (DC). Engagement of CD40 on mature DC and the cognate CD40 ligand on T cell activates c-Jun N-terminal MAPK, p38 and ERK1/2 MAPK pathways in mature DC. JNK-associated leucine zipper protein (JLP) is a scaffolding protein that interacted with p38 and JNK. The molecular mechanism underlying CD40 internalization and its physiological impact on DC functions remained unclear. Here we reported that the engagement of CD40 on the LPS-activated DC down-regulated the surface expression of CD40. We examined the role of the JLP protein in DC differentiation, and in the regulation of DC function(s) in vitro. In contrast to the abundant JLP expression observed in immortal cell lines, primary immature DC expressed low levels of the JLP proteins. The induction of the JLP protein expression was observed in the LPS-mature DC that were activated by CD40 ligation, and also in the poly I:C stimulated DC. JLP-silenced DC was impaired in regulating CD40 surface expression upon LPS stimulation and CD40 induced receptor internalization. Such aberrant change in the regulation of surface CD40 expression was associated with an augmented capacity of the JLP-silenced DC in IL-12 production. Collectively, our data identified a novel role of a scaffolding protein JLP in the regulation of surface CD40 expression and fine-tuning of DC function.

Monocyte CD40 expression in head and neck squamous cell carcinoma (HNSCC)

CD40, an antigen-presenting cell expressed costimulatory receptor molecule, binds to T cell expressed CD40-ligand (CD40-L). Using a mouse tumor model, we showed previously that lower CD40/CD40-L expression levels promoted tumor growth whereas higher CD40/CD40-L expression levels led to tumor regression indicating duality in CD40 functions. Whether CD40/CD40-L expressions are regulated in cancer patients is unknown. Herein, we show that the CD40 and CD40-L expressions on monocytes and T cells, respectively, decrease as the head and neck squamous cell carcinoma (HNSCC) patients progress from stage-I through stage-IV suggesting a novel CD40/CD40-L expression based staging of HNSCC tumor. The staging is confirmed by TNM and histo-pathological staging. The levels of soluble CD40 (sCD40) and sCD40-L are also modulated in patients' plasma. As CD40 expressing monocytes increase in the post-operative patients, CD40 expression levels are possibly regulated by tumor load. This change is accompanied by increased IL-12 expressing monocytes and decreased IL-10 expression levels. Thus, our findings on CD40/CD40-L expression in HNSCC patients bear significant implications.

Role of CD40 ligation in dendritic cell semimaturation

Background

DC are among the first antigen presenting cells encountering bacteria at mucosal surfaces, and play an important role in maintenance of regular homeostasis in the intestine. Upon stimulation DC undergo activation and maturation and as initiators of T cell responses they have the capacity to stimulate naïve T cells. However, stimulation of naïve murine DC with B. vulgatus or LPS at low concentration drives DC to a semimature (sm) state with low surface expression of activation-markers and a reduced capacity to activate T-cells. Additionally, semimature DC are nonresponsive to subsequent TLR stimulation in terms of maturation, TNF-α but not IL-6 production. Ligation of CD40 is an important mechanism in enhancing DC maturation, function and capacity to activate T-cells. We investigated whether the DC semimaturation can be overcome by CD40 ligation.

Results

Upon CD40 ligation smDC secreted IL-12p40 but not the bioactive heterodimer IL-12p70. Additionally, CD40 ligation of smDC resulted in an increased production of IL-6 but not in an increased expression of CD40. Analysis of the phosphorylation pattern of MAP kinases showed that in smDC the p38 phosphorylation induced by CD40 ligation is inhibited. In contrast, phosphorylation of ERK upon CD40 ligation was independent of the DC maturation state.

Conclusion

Our data show that the semimature differentiation state of DC can not be overcome by CD40 ligation. We suggest that the inability of CD40 ligation in overcoming DC semimaturation might contribute to the tolerogenic phenotype of semimature DC and at least partially account for maintenance of intestinal immune homeostasis.

CD40 expression levels modulate regulatory T cells in Leishmania donovani infection

Dendritic cell (DC)-expressed CD40 is shown to play crucial roles in eliciting effector T cell responses, primarily the proinflammatory CD4(+) Th subsets and cytotoxic CD8(+) T cells that eliminate various infections and tumors, respectively. In contrast, DCs are also implied in the generation of regulatory T cells (Tregs) that counteract the functions of the proinflammatory Th subsets and exacerbate infections. However, the role of DC-expressed CD40 in the generation of Tregs is unknown. In this study, we generated bone marrow-derived DCs from mice (on a BALB/c background) expressing different levels of CD40 and tested their relative efficiency in generating Tregs. We observed that low levels of CD40 expression were required for efficient Treg generation. DCs expressing low levels of CD40 induced Tregs, whereas DCs expressing high levels of CD40 induced effector T cells, possibly CD8(+)CD40(+) T cells with a contraregulatory activity; the adoptive transfer of the former DC exacerbated whereas the latter significantly reduced Leishmania donovani infection in BALB/c mice. Similarly, priming of mice with leishmanial Ag-pulsed DCs expressing high levels of CD40 induced host protection against L. donovani challenge infection. In contrast, priming with the low CD40-expressing DC resulted in aggravated infection as compared with the control mice. The results establish that CD40 can play differential roles in Treg differentiation and determine the course of infection. We demonstrate that the knowledge can be efficiently used in adoptive cell transfer therapy against an infectious disease.