Dendritic cells as cancer therapeutics

Tumor Immune Microenvironment in Intrahepatic Cholangiocarcinoma: Regulatory Mechanisms, Functions, and Therapeutic Implications

Treatment options for intrahepatic cholangiocarcinoma (iCCA), a highly malignant tumor with poor prognosis, are limited. Recent developments in immunotherapy and immune checkpoint inhibitors (ICIs) have offered new hope for treating iCCA. However, several issues remain, including the identification of reliable biomarkers of response to ICIs and immune-based combinations. Tumor immune microenvironment (TIME) of these hepatobiliary tumors has been evaluated and is under assessment in this setting in order to boost the efficacy of ICIs and to convert these immunologically "cold" tumors to "hot" tumors. Herein, the review TIME of ICCA and its critical function in immunotherapy. Moreover, this paper also discusses potential avenues for future research, including novel targets for immunotherapy and emerging treatment plans aimed to increase the effectiveness of immunotherapy and survival rates for iCCA patients.

Dysfunction of dendritic cells in tumor microenvironment and immunotherapy

Dendritic cells (DCs) comprise diverse cell populations that play critical roles in antigen presentation and triggering immune responses in the body. However, several factors impair the immune function of DCs and may promote immune evasion in cancer. Understanding the mechanism of DC dysfunction and the diverse functions of heterogeneous DCs in the tumor microenvironment (TME) is critical for designing effective strategies for cancer immunotherapy. Clinical applications targeting DCs summarized in this report aim to improve immune infiltration and enhance the biological function of DCs to modulate the TME to prevent cancer cells from evading the immune system. Herein, factors in the TME that induce DC dysfunction, such as cytokines, hypoxic environment, tumor exosomes and metabolites, and co-inhibitory molecules, have been described. Furthermore, several key signaling pathways involved in DC dysfunction and signal-relevant drugs evaluated in clinical trials were identified. Finally, this review provides an overview of current clinical immunotherapies targeting DCs, especially therapies with proven clinical outcomes, and explores future developments in DC immunotherapies.

Laponite Lights Calcium Flickers by Reprogramming Lysosomes to Steer DC Migration for An Effective Antiviral CD8+ T-Cell Response

Immunotherapy using dendritic cell (DC)-based vaccination is an established approach for treating cancer and infectious diseases; however, its efficacy is limited. Therefore, targeting the restricted migratory capacity of the DCs may enhance their therapeutic efficacy. In this study, the effect of laponite (Lap) on DCs, which can be internalized into lysosomes and induce cytoskeletal reorganization via the lysosomal reprogramming-calcium flicker axis, is evaluated, and it is found that Lap dramatically improves the in vivo homing ability of these DCs to lymphoid tissues. In addition, Lap improves antigen cross-presentation by DCs and increases DC-T-cell synapse formation, resulting in enhanced antigen-specific CD8+ T-cell activation. Furthermore, a Lap-modified cocktail (Lap@cytokine cocktail [C-C]) is constructed based on the gold standard, C-C, as an adjuvant for DC vaccines. Lap@C-C-adjuvanted DCs initiated a robust cytotoxic T-cell immune response against hepatitis B infection, resulting in > 99.6% clearance of viral DNA and successful hepatitis B surface antigen seroconversion. These findings highlight the potential value of Lap as a DC vaccine adjuvant that can regulate DC homing, and provide a basis for the development of effective DC vaccines.

Zinc-Organometallic Framework Vaccine Controlled-Release Zn2+ Regulates Tumor Extracellular Matrix Degradation Potentiate Efficacy of Immunotherapy

Tumor extracellular matrix (ECM) not only forms a physical barrier for T cells infiltration, but also regulates multiple immunosuppressive pathways, which is an important reason for immunotherapy failure. The cyclic guanosine monophosphate-adenosine monophosphate synthase-stimulator of interferon genes (cGAS-STING) pathway plays a key role in activating CD8+ T cells, maintaining CD8+ T cells stemness and enhancing the antitumor effect. Herein, a zinc-organometallic framework vaccine (ZPM@OVA-CpG) prepared by self-assembly, which achieves site-directed release of Zn2+ in dendritic cell (DC) lysosomes and tumor microenvironment under acidic conditions, is reported. The vaccine actively targets DC, significantly enhances cGAS-STING signal, promotes DC maturation and antigen cross-presentation, and induces strong activation of CD8+ T cells. Meanwhile, the vaccine reaches the tumor site, releasing Zn2+ , significantly up-regulates the activity of matrix metalloproteinase-2, degrades various collagen components of tumor ECM, effectively alleviates immune suppression, and significantly enhances the tumor infiltration and killing of CD8+ T cells. ZPM@OVA-CpG vaccine not only solves the problem of low antigen delivery efficiency and weak CD8+ T cells activation ability, but also achieves the degradation of tumor ECM via the vaccine for the first time, providing a promising therapeutic platform for the development of efficient novel tumor vaccines.

Exosome nanovesicles as potential biomarkers and immune checkpoint signaling modulators in lung cancer microenvironment: recent advances and emerging concepts

Lung cancer remains the leading cause of cancer-related deaths globally, and the survival rate remains low despite advances in diagnosis and treatment. The progression of lung cancer is a multifaceted and dynamic phenomenon that encompasses interplays among cancerous cells and their microenvironment, which incorporates immune cells. Exosomes, which are small membrane-bound vesicles, are released by numerous cell types in normal and stressful situations to allow communication between cells. Tumor-derived exosomes (TEXs) possess diverse neo-antigens and cargoes such as proteins, RNA, and DNA and have a unique molecular makeup reflecting tumor genetic complexity. TEXs contain both immunosuppressive and immunostimulatory factors and may play a role in immunomodulation by influencing innate and adaptive immune components. Moreover, they transmit signals that contribute to the progression of lung cancer by promoting metastasis, epithelial-mesenchymal transition (EMT), angiogenesis, and immunosuppression. This makes them a valuable resource for investigating the immune environment of tumors, which could pave the way for the development of non-invasive biomarkers that could aid in the prognosis, diagnosis, and immunotherapy of lung cancer. While immune checkpoint inhibitor (ICI) immunotherapy has shown promising results in treating initial-stage cancers, most patients eventually develop adaptive resistance over time. Emerging evidence demonstrates that TEXs could serve as a prognostic biomarker for immunotherapeutic response and have a significant impact on both systemic immune suppression and tumor advancement. Therefore, understanding TEXs and their role in lung cancer tumorigenesis and their response to immunotherapies is an exciting research area and needs further investigation. This review highlights the role of TEXs as key contributors to the advancement of lung cancer and their clinical significance in lung immune-oncology, including their possible use as biomarkers for monitoring disease progression and prognosis, as well as emerging shreds of evidence regarding the possibility of using exosomes as targets to improve lung cancer therapy.

PD-L1 methylation restricts PD-L1/PD-1 interactions to control cancer immune surveillance

Immune checkpoint inhibitors targeting programmed cell death protein 1 (PD-1) or programmed cell death 1 ligand 1 (PD-L1) have enabled some patients with cancer to experience durable, complete treatment responses; however, reliable anti-PD-(L)1 treatment response biomarkers are lacking. Our research found that PD-L1 K162 was methylated by SETD7 and demethylated by LSD2. Furthermore, PD-L1 K162 methylation controlled the PD-1/PD-L1 interaction and obviously enhanced the suppression of T cell activity controlling cancer immune surveillance. We demonstrated that PD-L1 hypermethylation was the key mechanism for anti-PD-L1 therapy resistance, investigated that PD-L1 K162 methylation was a negative predictive marker for anti-PD-1 treatment in patients with non-small cell lung cancer, and showed that the PD-L1 K162 methylation:PD-L1 ratio was a more accurate biomarker for predicting anti-PD-(L)1 therapy sensitivity. These findings provide insights into the regulation of the PD-1/PD-L1 pathway, identify a modification of this critical immune checkpoint, and highlight a predictive biomarker of the response to PD-1/PD-L1 blockade therapy.

The liver cancer immune microenvironment: Therapeutic implications for hepatocellular carcinoma

The liver is the sixth most common site of primary cancer in humans and the fourth leading cause of cancer-related death in the world. Hepatocellular carcinoma (HCC) accounts for 90% of liver cancers. HCC is a prevalent disease with a progression that is modulated by the immune system. Half of the patients with HCC receive systemic therapies, traditionally sorafenib or lenvatinib, as a first-line therapy. In the last few years, immune-checkpoint inhibitors (ICIs) have revolutionized cancer therapy and have gained an increased interest in the treatment of HCC. In 2020, the combination of atezolizumab (anti-programmed death-ligand 1) and bevacizumab (anti-vascular endothelial growth factor) improved overall survival over sorafenib, resulting in Food and Drug Administration (FDA) approval as a first-line treatment for patients with advanced HCC. Despite these major advances, a better molecular and cellular characterization of the tumor microenvironment is still needed because it has a crucial role in the development and progression of HCC. Inflamed (hot) and noninflamed (cold) HCC tumors and genomic signatures have been associated with response to ICIs. However, there are no additional biomarkers to guide clinical decision-making. Other immune-targeting strategies, such as adoptive T-cell transfer, vaccination, and virotherapy, are currently under development. This review provides an overview on the HCC immune microenvironment, different cellular players, current available immunotherapies, and potential immunotherapy modalities.

MMP9-Associated Tumor Stem Cells, CCL1-Silenced Dendritic Cells, and Cytokine-Induced Killer Cells Have a Remarkable Therapeutic Efficacy for Acute Myeloid Leukemia by Activating T Cells

Purpose

Dendritic cells (DC) are specialized antigen-presenting cells, and cytokine-induced killer (CIK) cells have a specific killing activity to a variety of tumors. However, the underlining mechanism and function of DC-CIK cells in acute myeloid leukemia (AML) remain largely elusive.

Methods

Gene expression profiles of leukemia patients were obtained from TCGA, DC cell components were evaluated using the quanTIseq method, and cancer stem cell scores were estimated using machine learning methods. The transcriptomes were obtained in DC-CIK cells from normal and AML patients by high-throughput sequencing. Large differentially expressed mRNAs were verified by RT-qPCR assay, and MMP9 and CCL1 were selected for subsequent studies in vivo and in vitro experiments.

Results

Significant positive correlations were found with DC versus cancer stem cells (p = 0.008) and the expression of MMP9 versus cancer stem cells (p = 0.018). MMP9 and CCL1 were found to be highly expressed in DC-CIK cells from AML patients. DC-CIK cells with MMP9 and CCL1 knockout alone had little effect on leukemia cells, while knockdown of MMP9 and CCL1 in DC-CIK cells increased cytotoxicity, suppressed proliferation, and induced apoptosis of leukemia cells. In addition, we proved that MMP9- and CCL1-silenced DC-CIK cells significantly elevated the CD³⁺CD⁴⁺ and CD³⁺CD⁸⁺ cells and lowered the CD4⁺PD-1⁺ and CD8⁺PD-1⁺ T cells. Meanwhile, blockage of MMP9 and CCL1 in DC-CIK cells dramatically increased IL-2 and IFN-γ, increased CD107aþ (LAMP-1) and granzyme B (GZMB), and downregulated PD-1, CTLA4, TIM3, and LAG3 T cells from AML patients and AML model mice. Furthermore, activated T cells in DC-CIK cells knocking down MMP9 and CCL1 also prevented proliferation and accelerated apoptosis of AML cells.

Conclusion

Our findings demonstrated that blockage of MMP9 and CCL1 in DC-CIK cells could markedly enhance the therapeutic efficiency in AML via activating T cells.

Dendritic Cell-Based Vaccines Against Cancer: Challenges, Advances and Future Opportunities

As the most potent professional antigen presenting cells, dendritic cells (DCs) have the ability to activate both naive CD4 and CD8 T cells. Recognized for their exceptional ability to cross-present exogenous antigens to prime naive antigen-specific CD8 T cells, DCs play a critical role in generating CD8 T cell immunity, as well as mediating CD8 T cell tolerance to tumor antigens. Despite the ability to potentiate host CD8 T cell-mediated anti-tumor immunity, current DC-based cancer vaccines have not yet achieved the promised success clinically with the exception of FDA-approved Provenge. Interestingly, recent studies have shown that type 1 conventional DCs (cDC1s) play a critical role in cross-priming tumor-specific CD8 T cells and determining the anti-tumor efficacy of cancer immunotherapies including immune checkpoint blockade (ICB). Together with promising clinical results in neoantigen-based cancer vaccines, there is a great need for DC-based vaccines to be further developed and refined either as monotherapies or in combination with other immunotherapies. In this review, we will present a brief review of DC development and function, discuss recent progress, and provide a perspective on future directions to realize the promising potential of DC-based cancer vaccines.

Application of dendritic cells in tumor immunotherapy and progress in the mechanism of anti-tumor effect of Astragalus polysaccharide (APS) modulating dendritic cells: a review

Dendritic cells (DCs) are potent antigen-presenting cells (APCs) that are essential in mediating the body's natural and adaptive immune responses. The body can regulate the function of DCs in various ways to enhance their antitumor effects. In the tumour microenvironment (TME), antigen-specific T cell responses are initiated through DC processing and delivery of tumour-associated antigens (TAAs); conversely, tumour cells inhibit DC recruitment by releasing metabolites, cytokines and other regulatory TME and function. Different subpopulations of DCs exist in tumour tissues, and their functions vary. Insight into DC subgroups in TME allows assessment of the effectiveness of tumour immunotherapy. Astragalus polysaccharide (APS) is the main component of the Chinese herb Astragalus membranaceus. The study found that the antitumor effects of APS are closely related to DCs. APS can promote the expression of surface molecules CD80 and CD86, promote the maturation of DCs, and activate CTL to exert antitumor effects. We reviewed the application of DCs in tumor immunotherapy and the mechanism of modulation of DCs by Astragalus polysaccharide to provide new directions and strategies for tumor therapy and new drug development.

Harnessing the Immunogenic Potential of Gold Nanoparticle-Based Platforms as a Therapeutic Strategy in Breast Cancer Immunotherapy: A Mini Review

Breast cancer remains the most common malignancy among women worldwide. Although the implementation of mammography has dramatically increased the early detection rate, conventional treatments like chemotherapy, radiation therapy, and surgery, have significantly improved the prognosis for breast cancer patients. However, about a third of treated breast cancer patients are known to suffer from disease recurrences and progression to metastasis. Immunotherapy has recently gained traction due to its ability to establish long-term immune surveillance, and response for the prevention of disease recurrence and extension of patient survival. Current research findings have revealed that gold nanoparticles can enhance the safety and efficacy of cancer immunotherapy, through their unique intrinsic properties of good biocompatibility, durability, convenient surface modification, as well as enhanced permeability and retention effect. Gold nanoparticles are also able to induce innate immune responses through the process of immunogenic cell death, which can lead to the establishment of lasting adaptive immunity. As such gold nanoparticles are considered as good candidates for next generation immunotherapeutic strategies. This mini review gives an overview of gold nanoparticles and their potential applications in breast cancer immunotherapeutic strategies.

Biomimetic and Materials-Potentiated Cell Engineering for Cancer Immunotherapy

In cancer immunotherapy, immune cells are the main force for tumor eradication. However, they appear to be dysfunctional due to the taming of the tumor immunosuppressive microenvironment. Recently, many materials-engineered strategies are proposed to enhance the anti-tumor effect of immune cells. These strategies either utilize biomimetic materials, as building blocks to construct inanimate entities whose functions are similar to natural living cells, or engineer immune cells with functional materials, to potentiate their anti-tumor effects. In this review, we will summarize these advanced strategies in different cell types, as well as discussing the prospects of this field.

Anti-hepatoma Effect of DC2.4 Cells Transfected with Tumor-Associated Antigen Cdc25C In Vitro

OBJECTIVE

Cell division cyclin 25 homolog C (Cdc25C) is a tumor-associated antigen candidate gene, and this may be used as an effective target in cancer treatment. The present study aims to evaluate the lysis effect of cytotoxic T lymphocytes (CTLs) induced by dendritic cell line DC2.4 overexpressing Cdc25C, and the feasibility of Cdc25C as a component in hepatoma immunotherapy.

METHODS

The mouse Cdc25C gene was ligated into a lentiviral vector, and transfected into DC2.4 cells. The DC2.4 cell phenotype and cytokine secretion were determined by flow cytometry and ELISA, respectively. CD8⁺ T cells were sorted from the spleens of C57BL/6 mice using a magnetic bead sorting kit obtained from Miltenyi Biotech, Germany, and co-cultured with DC2.4 cells for one week as effector cells. Then, IL-2, granzyme B and perforin were detected in the CTL culture medium by ELISA. Next, time-resolved fluorescence immunoassay was used to detect the immune killing effect of Cdc25C-specific CTLs on target cells. Meanwhile, the effect of blocking MHC-I sites on target cells with a monoclonal anti-MHC-I antibody was evaluated.

RESULTS

The results revealed that Cdc25C could be stably overexpressed in DC2.4 cells by LV-Cdc25C infection. DC2.4 cells transfected with LV-Cdc25C secreted more IL-6, IL-12, TNF-α and IFN-γ, and had higher expression levels of CD40, CD86, CCR7 and MHC-II than unaltered DC2.4 cells. The elevated Cdc25C in dendritic cells also further increased the secretion of IL-2, granzyme B and perforin to elicit Cdc25C-specific CTLs, and induced the higher cytotoxicity in Hepa1-6 cell lines (P<0.05), but this had no effect on the target cells when MHC-I monoclonal antibodies were blocked.

CONCLUSION

DC2.4 cells transfected with LV-Cdc25C can induce specific CTLs, and result in a strong cellular immune response. The dendritic cells that overexpress Cdc25C may be useful for hepatoma immunotherapy.

CAL-1 as Cellular Model System to Study CCR7-Guided Human Dendritic Cell Migration

Dendritic cells (DCs) are potent and versatile professional antigen-presenting cells and central for the induction of adaptive immunity. The ability to migrate and transport peripherally acquired antigens to draining lymph nodes for subsequent cognate T cell priming is a key feature of DCs. Consequently, DC-based immunotherapies are used to elicit tumor-antigen specific T cell responses in cancer patients. Understanding chemokine-guided DC migration is critical to explore DCs as cellular vaccines for immunotherapeutic approaches. Currently, research is hampered by the lack of appropriate human cellular model systems to effectively study spatio-temporal signaling and CCR7-driven migration of human DCs. Here, we report that the previously established human neoplastic cell line CAL-1 expresses the human DC surface antigens CD11c and HLA-DR together with co-stimulatory molecules. Importantly, if exposed for three days to GM-CSF, CAL-1 cells induce the endogenous expression of the chemokine receptor CCR7 upon encountering the clinically approved TLR7/8 agonist Resiquimod R848 and readily migrate along chemokine gradients. Further, we demonstrate that CAL-1 cells can be genetically modified to express fluorescent (GFP)-tagged reporter proteins to study and visualize signaling or can be gene-edited using CRISPR/Cas9. Hence, we herein present the human CAL-1 cell line as versatile and valuable cellular model system to effectively study human DC migration and signaling.

Gold Compounds and the Anticancer Immune Response

Gold compounds are not only well-explored for cytotoxic effects on tumors, but are also known to interact with the cancer immune system. The immune system deploys innate and adaptive mechanisms to protect against pathogens and prevent malignant transformation. The combined action of gold compounds with the activated immune system has shown promising results in cancer therapy through in vivo and in vitro experiments. Gold compounds are known to induce innate immune responses; however, these responses may contribute to adaptive immune responses. Gold compounds play the role of a major hapten that acts synergistically in innate immunity. Gold compounds support cancer cell antigenicity and promote anti-tumor immune response by inducing the release of CRT, ATP, HMGB1, HSP, and NKG2D to enhance immunogenicity. Gold compounds affect various immune cells (including suppressor regulatory T cells), inhibit myeloid derived suppressor cells, and enhance the function and number of dendritic cells. Gold nanoparticles (AuNPs) have potential for improving the effect of immunotherapy and reducing the toxicity and side effects of the treatment process. Thus, AuNPs provide an ideal opportunity for exploring the combination of anticancer gold compounds and immunotherapeutic interventions.

Selenium Regulation of the Immune Function of Dendritic Cells in Mice Through the ERK, Akt and RhoA/ROCK Pathways

Selenium levels can regulate the function of T cells, macrophages, B cells, natural killer cells and other immune cells. However, the effect of selenium on the immune function of dendritic cells (DCs) isolated from selenium-supplemented mice is unknown. In this study, C57BL/6J mice were randomly divided into three groups and fed diets containing low (0.08 ppm), medium (0.25 ppm) or high (1 ppm) selenium levels for 8 weeks. Immature (imDCs) and mature (mDCs) dendritic cells were then isolated from the bone marrow. Next, the migration, phagocytic capacity and mixed lymphocyte reaction (MLR) for imDCs and mDCs were detected by transwell and flow cytometry. The levels of C-C chemokine receptor type 7 (CCR7), major histocompatibility complex II (MHCII) and reactive oxygen species (ROS) were assayed by flow cytometry. F-actin and superoxide dismutase (SOD) activity was detected by fluorescence microscopy and SOD assay kit, respectively. In addition, the extracellular signal-regulated kinase (ERK), Akt, Ras homolog gene family member A/Rho-associated protein kinase (RhoA/ROCK) signalling, selenoprotein K (SELENOK) and glutathione peroxidase 1 (GPX1) levels were measured by western blot analysis. The results indicated that selenium deficiency enhanced the migration of imDCs by ROS and SELENOK-mediated ERK, Akt and RhoA/ROCK pathways but impaired the antigen uptake of imDCs. Although a high selenium level inhibited the migration of imDCs, it had no effect on phagocytic capacity. For mDCs, low selenium levels impaired free migration, and high levels inhibited the chemotactic migration involved in F-actin and CCR7, respectively. Low and high selenium levels impaired the MLR by inhibiting MHCII surface localisation, which might be related to ROS- and SELENOK-mediated ERK, Akt and RhoA/ROCK signalling pathways. In summary, selenium may regulate the immune function of mouse DCs through the ROS- and SELENOK-mediated ERK, Akt and RhoA/ROCK signalling.

Mannose-Modified Chitosan Poly(lactic-co-glycolic acid) Microspheres Act as a Mannose Receptor-Mediated Delivery System Enhancing the Immune Response

The mannose receptor (MAN-R)-targeted delivery system is commonly used to deliver antigens to macrophages or immature dendritic cells (DCs) to promote the efficiency of antigen presentation. To maximize the enhancement effects of chitosan (CS) and induce an efficient humoral and cellular immune response against an antigen, we encapsulated ovalbumin (OVA) in poly(lactic-co-glycolic acid) (PLGA) microspheres (MPs) and conjugated it with MAN-modified CS to obtain MAN-R-targeting nano-MPs (MAN-CS-OVA-PLGA-MPs). The physicochemical properties, drug loading rate, and immunomodulation activity of MAN-CS-OVA-PLGA-MPs were evaluated. In vitro, MAN-CS-OVA-PLGA-MPs (80 μg mL⁻¹) could enhance the proliferation of DCs and increase their phagocytic efficiency. In vivo, MAN-CS-OVA-PLGA-MPs significantly increased the ratio of CD3⁺CD4⁺/CD3⁺CD8⁺ T cells, increased CD80⁺, CD86⁺, and MHC II expression in DCs, and improved OVA-specific IgG, IgG1, IgG2a, and IgG2b antibodies. Moreover, MAN-CS-OVA-PLGA-MPs promoted cytokine (IFN-γ, IL-4, and IL-6) production in mice. Taken together, our results show that MAN-CS-OVA-PLGA-MPs may act by activating the T cells to initiate an immune response by promoting the maturation of dendritic cells and improving their antigen presentation efficiency. The current study provides a basis for the use of MAN-CS-OVA-PLGA-MPs as an antigen and adjuvant delivery system targeting the MAN-R on the surface of macrophages and dendritic cells.

Therapeutic efficacy of dendritic cell vaccine combined with programmed death 1 inhibitor for hepatocellular carcinoma

BACKGROUND AND AIM

Hepatocellular carcinoma (HCC) remains a serious cause of cancer-related deaths worldwide. Developing new therapeutic strategies is urgently needed to improve the outcomes of HCC patients. Dendritic cell (DC)-based vaccines and programmed death 1 (PD-1) immune checkpoint inhibitors have been regarded as potential immunotherapeutics for HCC. However, the therapeutic efficacy of combining these two treatments for HCC remains to be evaluated.

METHODS

In this study, DCs were derived from mouse bone marrow and pulsed with mouse HCC cell lysates to generate a DC vaccine. A monoclonal antibody that blocks the interaction of mouse PD-1 with its ligands was used as a PD-1 inhibitor. An orthotopic HCC mouse model was established to assess the effect of a DC vaccine in combination with a PD-1 inhibitor on overall survival and tumor volume.

RESULTS

Compared with the untreated control, single treatment with a DC vaccine or PD-1 inhibitor prolonged the overall survival and reduced the tumor volume of HCC mice. Further, compared with the single treatment with the DC vaccine or the PD-1 inhibitor, a combination treatment using both agents elicited a higher cytotoxicity of T cells against HCC cells and resulted in a better overall survival, smaller tumor volume, and greater tumor cell apoptosis in HCC mice.

CONCLUSIONS

Our results suggest that a combination treatment with DC vaccine and PD-1 inhibitor may be a promising therapeutic strategy for HCC.

Characterization of a Tumor-Microenvironment-Relevant Gene Set Based on Tumor Severity in Colon Cancer and Evaluation of Its Potential for Dihydroartemisinin Targeting

Colon cancer (COAD) is a leading cause of cancer mortality in the world. Most patients with COAD die as a result of cancer cell metastasis. However, the mechanisms underlying the metastatic phenotype of COAD remain unclear. Instead, particular features of the tumor microenvironment (TME) could predict adverse outcomes including metastasis in patients with COAD, and the role of TME in governing COAD progression is undeniable. Therefore, exploring the role of TME in COAD may help us better understand the molecular mechanisms behind COAD progression which may improve clinical outcomes and quality of patients. Here, we identified a Specific TME Regulatory Network including AEBP1, BGN, POST, and FAP (STMERN) that is highly involved in clinical outcomes of patients with COAD. Comprehensive in silico analysis of our study revealed that the STMERN is highly correlated with the severity of COAD. Meanwhile, our results reveal that the STMERN might be associated with immune infiltration in COAD. Importantly, we show that dihydroartemisinin (DHA) potentially interacts with the STMERN. We suggest that DHA might contribute to immune infiltration through regulating the STMERN in COAD. Taken together, our data provide a set of biomarkers of progression and poor prognosis in COAD. These findings could have potential prognostic and therapeutic implications in the progression of COAD.

Preclinical models and technologies to advance nanovaccine development

The remarkable success of targeted immunotherapies is revolutionizing cancer treatment. However, tumor heterogeneity and low immunogenicity, in addition to several tumor-associated immunosuppression mechanisms are among the major factors that have precluded the success of cancer vaccines as targeted cancer immunotherapies. The exciting outcomes obtained in patients upon the injection of tumor-specific antigens and adjuvants intratumorally, reinvigorated interest in the use of nanotechnology to foster the delivery of vaccines to address cancer unmet needs. Thus, bridging nano-based vaccine platform development and predicted clinical outcomes the selection of the proper preclinical model will be fundamental. Preclinical models have revealed promising outcomes for cancer vaccines. However, only few cases were associated with clinical responses. This review addresses the major challenges related to the translation of cancer nano-based vaccines to the clinic, discussing the requirements for ex vivo and in vivo models of cancer to ensure the translation of preclinical success to patients.

Single-cell RNA sequencing of blood antigen-presenting cells in severe COVID-19 reveals multi-process defects in antiviral immunity

COVID-19 can lead to life-threatening respiratory failure, with increased inflammatory mediators and viral load. Here, we perform single-cell RNA-sequencing to establish a high-resolution map of blood antigen-presenting cells (APCs) in 15 patients with moderate or severe COVID-19 pneumonia, at day 1 and day 4 post admission to intensive care unit or pulmonology department, as well as in 4 healthy donors. We generated a unique dataset of 81,643 APCs, including monocytes and rare dendritic cell (DC) subsets. We uncovered multi-process defects in antiviral immune defence in specific APCs from patients with severe disease: (1) increased pro-apoptotic pathways in plasmacytoid DCs (pDCs, key effectors of antiviral immunity), (2) a decrease of the innate sensors TLR9 and DHX36 in pDCs and CLEC9a+ DCs, respectively, (3) downregulation of antiviral interferon-stimulated genes in monocyte subsets and (4) a decrease of major histocompatibility complex (MHC) class II-related genes and MHC class II transactivator activity in cDC1c+ DCs, suggesting viral inhibition of antigen presentation. These novel mechanisms may explain patient aggravation and suggest strategies to restore the defective immune defence.

Clinical applications of monitoring immune status with 90 immune cell subsets in human whole blood by 10-color flow cytometry

INTRODUCTION

The immune system may involve and predict the different prognosis and therapy consequences. So, it's important to monitor and evaluate the immune status before and after treatments.

METHODS

Flow cytometry is the best technology to perform immune monitoring, because it can detect immune cells using small amount of sample in a short time. The whole blood is the ideal sample for immune status monitoring, since it includes almost all the immune cells and it's relatively easy to obtain and less invasive than bone marrow or lymph node.

RESULTS

Here we developed and validated a 10-color panel with only four tubes containing 29 antibodies to monitor 90 immune cell subsets in 2 ml whole blood samples. The major immune cell populations detected by our panel included T cell subsets (CD3⁺ total T, Th, Tc, Treg, CD8^hi , CD8^low , αβTCR, γδTCR, naïve, and memory T), T cell activation markers (CD25, CD69, and HLA-DR) and one immune checkpoint PD1, B cell subsets (B1, switched memory, non-switched, naïve B, and CD27^- IgD^- B cells), neutrophils, basophils, four monocytic cell subsets, dendritic cells (pDCs and mDCs), and four NK cell subsets. These panels of antibodies had been applied to monitor immune status (percentage and absolute number) in total 303 cases with various diseases, such as leukemia (AML, CML, MM, and ALL), lymphoma (B cells and NK/T cells), cancers (colon, lung, prostate, and breast), immune deficiencies, and autoimmune diseases.

CONCLUSION

We provided proof of feasibility for clinical monitoring immune status and guiding immunotherapy by multicolor flow cytometry testing.

Nanoparticles as Smart Carriers for Enhanced Cancer Immunotherapy

Cancer immunotherapy has emerged as a promising strategy for the treatment of many forms of cancer by stimulating body's own immune system. This therapy not only eradicates tumor cells by inducing strong anti-tumor immune response but also prevent their recurrence. The clinical cancer immunotherapy faces some insurmountable challenges including high immune-mediated toxicity, lack of effective and targeted delivery of cancer antigens to immune cells and off-target side effects. However, nanotechnology offers some solutions to overcome those limitations, and thus can potentiate the efficacy of immunotherapy. This review focuses on the advancement of nanoparticle-mediated delivery of immunostimulating agents for efficient cancer immunotherapy. Here we have outlined the use of the immunostimulatory nanoparticles as a smart carrier for effective delivery of cancer antigens and adjuvants, type of interactions between nanoparticles and the antigen/adjuvant as well as the factors controlling the interaction between nanoparticles and the receptors on antigen presenting cells. Besides, the role of nanoparticles in targeting/activating immune cells and modulating the immunosuppressive tumor microenvironment has also been discussed extensively. Finally, we have summarized some theranostic applications of the immunomodulatory nanomaterials in treating cancers based on the earlier published reports.

Cell Therapy for Liver Disease: From Promise to Reality

Over the last decade, there has been a considerable progress in the development of cell therapy products for the treatment of liver diseases. The quest to generate well-defined homogenous cell populations with defined mechanism(s) of action has enabled the progression from use of autologous bone marrow stem cells comprising of heterogeneous cell populations to allogeneic cell types such as monocyte-derived macrophages, regulatory T cells, mesenchymal stromal cells, macrophages, etc. There is growing evidence regarding the multiple molecular mechanisms pivotal to various therapeutic effects and hence, careful selection of cell therapy product for the desired putative effects is crucial. In this review, we have presented an overview of the cell therapies that have been developed thus far, with preclinical and clinical evidence for their use in liver disease. Limitations associated with these therapies have also been discussed. Despite the advances made, there remain multiple challenges to overcome before cell therapies can be considered as viable treatment options, and these include larger scale clinical trials, scalable production of cells according to good manufacturing practice standards, pathways for delivery of cell therapy within hospital environments, and costs associated with the production.

Promoting the activation of T cells with glycopolymer-modified dendritic cells by enhancing cell interactions

Dendritic cell (DC) modification to enhance antigen presentation is a valuable strategy in cancer immune therapy. Other than focusing on regulating interactions between DC and antigens, we intend to promote cell interactions between DC and T cell by cell surface engineering. T cell activation is greatly improved and generates higher tumor toxicity with the aid of the synthetic glycopolymer modified on the DC surface, although the glycopolymer alone shows no effect. The great promotion of DC-T cell attraction is revealed by cell image tracking in terms of both frequency and duration of contacts. Our findings provide a new method of T cell activation by these engineered "sweet DCs." This strategy is beneficial for developing more efficient DC-based vaccines.

Combination therapy with dendritic cell vaccine and programmed death ligand 1 immune checkpoint inhibitor for hepatocellular carcinoma in an orthotopic mouse model

Background

Hepatocellular carcinoma (HCC) is among the most common and lethal human cancers worldwide. Despite remarkable advances in treatment, high mortality in HCC patients remains a big challenge. To develop novel therapeutic strategies for HCC is thus urgently needed to improve patient survival. Dendritic cells (DC)-based vaccines can induce tumor-specific immunity and have emerged as a promising approach for treating HCC patients; however, its effectiveness needs to be improved. Recently, blockade of programmed death ligand 1 (PD-L1) immune checkpoint pathway has been shown to enhance anti-tumor immune responses and exhibited great potential in HCC therapy.

Methods

In this study, we generated DC vaccine by pulsing the C57BL/6J mouse bone marrow-derived DC with mouse hepatoma Hep-55.1C cell lysate. We developed a therapeutic strategy combining DC vaccine and PD-L1 inhibitor for HCC and evaluated its efficacy in an orthotopic HCC mouse model in which Hep-55.1C cells were directly injected into left liver lobe of C57BL/6J mouse.

Results

Compared with a control group of mice, groups of mice treated with DC vaccine or PD-L1 inhibitor had significantly improved overall survival, reduced tumor volume, and increased tumor cell apoptosis. Remarkably, combination treatment with DC vaccine and PD-L1 inhibitor led to considerably longer overall survival, smaller tumor volume, and higher tumor cell apoptosis of mice than either treatment alone in a dose-dependent manner through inducing a stronger anti-tumor cytotoxic T cell response.

Conclusion

Our data suggested that combination therapy with DC vaccine and PD-L1 inhibitor might have great promise as a novel treatment strategy for HCC.

The IUPHAR Guide to Immunopharmacology: connecting immunology and pharmacology

Given the critical role that the immune system plays in a multitude of diseases, having a clear understanding of the pharmacology of the immune system is crucial to new drug discovery and development. Here we describe the International Union of Basic and Clinical Pharmacology (IUPHAR) Guide to Immunopharmacology (GtoImmuPdb), which connects expert-curated pharmacology with key immunological concepts and aims to put pharmacological data into the hands of immunologists. In the pursuit of new therapeutics, pharmacological databases are a vital resource to researchers through providing accurate information on the fundamental science underlying drug action. This extension to the existing IUPHAR/British Pharmacological Society Guide to Pharmacology supports research into the development of drugs targeted at modulating immune, inflammatory or infectious components of disease. To provide a deeper context for how the resource can support research we show data in GtoImmuPdb relating to a case study on the targeting of vascular inflammation.

Opportunities for Conventional and in Situ Cancer Vaccine Strategies and Combination with Immunotherapy for Gastrointestinal Cancers, A Review

Survival of gastrointestinal cancer remains dismal, especially for metastasized disease. For various cancers, especially melanoma and lung cancer, immunotherapy has been proven to confer survival benefits, but results for gastrointestinal cancer have been disappointing. Hence, there is substantial interest in exploring the usefulness of adaptive immune system education with respect to anti-cancer responses though vaccination. Encouragingly, even fairly non-specific approaches to vaccination and immune system stimulation, involving for instance influenza vaccines, have shown promising results, eliciting hopes that selection of specific antigens for vaccination may prove useful for at least a subset of gastrointestinal cancers. It is widely recognized that immune recognition and initiation of responses are hampered by a lack of T cell help, or by suppressive cancer-associated factors. In this review we will discuss the hurdles that limit efficacy of conventional cancer therapeutic vaccination methods (e.g., peptide vaccines, dendritic cell vaccination). In addition, we will outline other forms of treatment (e.g., radiotherapy, chemotherapy, oncolytic viruses) that also cause the release of antigens through immunogenic tumor cell death and can thus be considered unconventional vaccination methods (i.e., in situ vaccination). Finally, we focus on the potential additive value that vaccination strategies may have for improving the effect immunotherapy. Overall, a picture will emerge that although the field has made substantial progress, successful immunotherapy through the combination with cancer antigen vaccination, including that for gastrointestinal cancers, is still in its infancy, prompting further intensification of the research effort in this respect.

Alarmin-painted exosomes elicit persistent antitumor immunity in large established tumors in mice

Treating large established tumors is challenging for dendritic cell (DC)-based immunotherapy. DC activation with tumor cell-derived exosomes (TEXs) carrying multiple tumor-associated antigen can enhance tumor recognition. Adding a potent adjuvant, high mobility group nucleosome-binding protein 1 (HMGN1), boosts DCs’ ability to activate T cells and improves vaccine efficiency. Here, we demonstrate that TEXs painted with the functional domain of HMGN1 (TEX-N1ND) via an exosomal anchor peptide potentiates DC immunogenicity. TEX-N1ND pulsed DCs (DC_TEX-N1ND) elicit long-lasting antitumor immunity and tumor suppression in different syngeneic mouse models with large tumor burdens, most notably large, poorly immunogenic orthotopic hepatocellular carcinoma (HCC). DC_TEX-N1ND show increased homing to lymphoid tissues and contribute to augmented memory T cells. Importantly, N1ND-painted serum exosomes from cancer patients also promote DC activation. Our study demonstrates the potency of TEX-N1ND to strengthen DC immunogenicity and to suppress large established tumors, and thus provides an avenue to improve DC-based immunotherapy.

The use of tumour exosome-activated dendritic cell (DC) immunotherapy shows promise for the treatment of large established tumours. Here, the authors generate alarmin HMGN1-attached tumour exosomes which significantly improve therapy efficacy by boosting DC activation in several preclinical mouse models.

Cancer/testis antigens expression during cultivation of melanoma and soft tissue sarcoma cells

BACKGROUND

Autologous dendritic cells (DC) loaded with tumor-associated antigens (TAAs) are a promising approach for anticancer immunotherapy. Polyantigen lysates appear to be an excellent source of TAAs for loading onto the patient's dendritic cells. Cancer/testis antigens (CTA) are expressed by a wide range of tumors, but are minimally expressed on normal tissues, and could serve as a universal target for immunotherapy. However, CTA expression levels can vary significantly in patients with the same tumor type. We proposed that patients who do not respond to DC-based therapy may have distinct features of the CTA expression profile on tumor cells.

PATIENTS AND METHODS

We compared the gene expression of the principal families CTA in 22 melanoma and 27 soft tissue and bone sarcomas cell lines (STBS), received from patients and used for DC vaccine preparation.

RESULTS

The majority (47 of 49, 95.9%) cell lines showed CTA gene activity. The incidence of gene expression of GAGE, NYESO1, MAGEA1, PRAME's was significantly different (adj. p < 0.05) between melanoma and sarcoma cell lines. The expression of the SCP1 gene was detected neither in melanoma cells nor in the STBS cells. Clustering by the gene expression profile revealed four different expression patterns. We found three main patterns types: hyperexpression of multiple CTA, hyperexpression of one CTA with almost no expression of others, and no expression of CTA. All clusters types exist in melanoma and sarcoma cell lines. We observed dependence of killing efficacy from the PRAME (rho = 0.940, adj. p < 0.01) expression during real-time monitoring with the xCELLigence system of the interaction between melanoma or sarcoma cells with the T-lymphocytes activated by the lysate of selected allogenous melanoma cell lines with high expression of CTA.

CONCLUSION

Our results demonstrate that one can use lysates from allogeneic melanoma cell lines as a source of CTA for DC load during the production of anticancer vaccines for the STBS treatment. Patterns of CTA expression should be evaluated as biomarkers of response in prospective clinical trials.

Ca2+-Mediated Surface Polydopamine Engineering to Program Dendritic Cell Maturation

Engineering of cell surfaces holds promise in manipulating cellular activities in a physicochemical route as a complement to the biological approach. Mediated by Ca²⁺, a quick and convenient yet cytocompatible method is used to achieve surface engineering, by which polydopamine nanostructures can be in situ grown onto dendritic cell (DC) surfaces within 10 min. Ca²⁺, as the physical bridge between the negative cell surface and polydopamine, avoids the direct chemical polymerization of polydopamine onto the cell surface, critically important to maintain the cell viability. As a proof of concept in potential applications, this cell surface engineering shows a good control toward DC maturation. Upon surface polydopamine engineering, bone-marrow-derived DC exhibits a unique bidirectional control of maturation. The polydopamine structure enables effective suppression of DC activation by acting as an efficient scavenger of reactive oxygen species, a key signal during maturation. Conversely, an 808 nm laser irradiation can remotely relieve the suppressed state and effectively activate DC maturation by the photoheat effect of polydopamine (39 °C). The work provides an easily implemented, straightforward approach to achieve cell surface engineering, through which the DC maturation can be controlled.

Janus or Hydra: The Many Faces of T Helper Cells in the Human Tumour Microenvironment

CD4+ T helper (T_H) cells are key regulators in the tumour immune microenvironment (TIME), mediating the adaptive immunological response towards cancer, mainly through the activation of cytotoxic CD8+ T cells. After antigen recognition and proper co-stimulation, naïve T_H cells are activated, undergo clonal expansion, and release cytokines that will define the differentiation of a specific effector T_H cell subtype. These different subtypes have different functions, which can mediate both anti- and pro-tumour immunological responses. Here, we present the dual role of T_H cells restraining or promoting the tumour, the factors controlling their homing and differentiation in the TIME, their influence on immunotherapy, and their use as prognostic indicators.

Distinguishing human peripheral blood CD16+ myeloid cells based on phenotypic characteristics

Myeloid lineage cells present in human peripheral blood include dendritic cells (DC) and monocytes. The DC are identified phenotypically as HLA-DR⁺ cells that lack major cell surface lineage markers for T cells (CD3), B cells (CD19, CD20), NK cells (CD56), red blood cells (CD235a), hematopoietic stem cells (CD34), and Mo that express CD14. Both DC and Mo can be phenotypically divided into subsets. DC are divided into plasmacytoid DC, which are CD11c^- , CD304⁺ , CD85g⁺ , and myeloid DC that are CD11c⁺ . The CD11c⁺ DC are readily classified as CD1c⁺ DC and CD141⁺ DC. Monocytes are broadly divided into the CD14⁺ CD16^- (classical) and CD14^dim CD16⁺ subsets (nonclassical). A population of myeloid-derived cells that have DC characteristics, that is, HLA-DR⁺ and lacking lineage markers including CD14, but express CD16 are generally clustered with CD14^dim CD16⁺ monocytes. We used high-dimensional clustering analyses of fluorescence and mass cytometry data, to delineate CD14⁺ monocytes, CD14^dim CD16⁺ monocytes (CD16⁺ Mo), and CD14^- CD16⁺ DC (CD16⁺ DC). We sought to identify the functional and kinetic relationship of CD16⁺ DC to CD16⁺ Mo. We demonstrate that differentiation of CD16⁺ DC and CD16⁺ Mo during activation with IFNγ in vitro and as a result of an allo-hematopoietic cell transplant (HCT) in vivo resulted in distinct populations. Recovery of blood CD16⁺ DC in both auto- and allo-(HCT) patients after myeloablative conditioning showed similar reconstitution and activation kinetics to CD16⁺ Mo. Finally, we show that expression of the cell surface markers CD300c, CCR5, and CLEC5a can distinguish the cell populations phenotypically paving the way for functional differentiation as new reagents become available.

Trial watch: dendritic cell vaccination for cancer immunotherapy

Dendritic- cells (DCs) have received considerable attention as potential targets for the development of anticancer vaccines. DC-based anticancer vaccination relies on patient-derived DCs pulsed with a source of tumor-associated antigens (TAAs) in the context of standardized maturation-cocktails, followed by their reinfusion. Extensive evidence has confirmed that DC-based vaccines can generate TAA-specific, cytotoxic T cells. Nonetheless, clinical efficacy of DC-based vaccines remains suboptimal, reflecting the widespread immunosuppression within tumors. Thus, clinical interest is being refocused on DC-based vaccines as combinatorial partners for T cell-targeting immunotherapies. Here, we summarize the most recent preclinical/clinical development of anticancer DC vaccination and discuss future perspectives for DC-based vaccines in immuno-oncology.

Re-expression of CD14 in Response to a Combined IL-10/TLR Stimulus Defines Monocyte-Derived Cells With an Immunoregulatory Phenotype

Interleukin 10 is a central regulator of the antigen-presenting function of myeloid cells. It exerts immunomodulatory effects in vivo and induces a regulatory phenotype in monocyte-derived cells in vitro. We analyzed phenotype and function of monocytic cells in vitro in relation to the cytokine milieu and the timing of TLR-based activation. In GM-CSF/IL-4 cultured human monocytic cells, we identified two, mutually exclusive cell populations arising from undifferentiated cells: CD83⁺ fully activated dendritic cells and CD14⁺ macrophage like cells. Re-expression of CD14 occurs primarily after a sequential trigger with a TLR signal following IL-10 preincubation. This cell population with re-expressed CD14 greatly differs in phenotype and function from the CD83⁺ cells. Detailed analysis of individual subpopulations reveals that exogenous IL-10 is critical for inducing the shift toward the CD14+ population, but does not affect individual changes in marker expression or cell function in most cases. Thus, plasticity of CD14 expression, defining a subset of immunoregulatory cells, is highly relevant for the composition of cellular products (such as DC vaccines) as it affects the function of the total product.

RNA delivery biomaterials for the treatment of genetic and rare diseases

Genetic and rare diseases (GARDs) affect more than 350 million patients worldwide and remain a significant challenge in the clinic. Hence, continuous efforts have been made to bridge the significant gap between the supply and demand of effective treatments for GARDs. Recent decades have witnessed the impressive progress in the fight against GARDs, with an improved understanding of the genetic origins of rare diseases and the rapid development in gene therapy providing a new avenue for GARD therapy. RNA-based therapeutics, such as RNA interference (RNAi), messenger RNA (mRNA) and RNA-involved genome editing technologies, demonstrate great potential as a therapy tool for treating genetic associated rare diseases. In the meantime, a variety of RNA delivery vehicles were established for boosting the widespread applications of RNA therapeutics. Among all the RNA delivery platforms which enable the systemic applications of RNAs, non-viral RNA delivery biomaterials display superior properties and a few biomaterials have been successfully exploited for achieving the RNA-based gene therapies on GARDs. In this review article, we focus on recent advances in the development of novel biomaterials for delivery of RNA-based therapeutics and highlight their applications to treat GARDs.

The Expression of ILT4 in Myeloid Dendritic Cells in Patients with Hepatocellular Carcinoma

Immunoglobulin-like transcript (ILT) 4 is an inhibitory immune receptor of the immunoglobulin superfamily, which could deliver inhibitory signals and induce immunosuppression. The significance of the expression of ILT4 in mDCs subsets in patients with hepatocellular carcinoma (HCC) remains unclear. In this study, the frequency of mDCs subsets in the peripheral blood of 121 patients with HCC and 103 normal controls, and in the tumor and tumor free liver tissues (TFL) of 43 HCC patients was analyzed by flow cytometry. Then, the expressions of ILT4 in mDCs subsets in the microenvironment of liver cancer were also analyzed. Results showed that the percentage of CD1c⁺ subset was dramatically decreased in peripheral blood mononuclear cells (PBMCs) of HCC patients compared with normal controls, and also significantly decreased in tumor tissue compared with the TFL. The decreased of CD1c⁺ subset in blood could be a diagnostic factor for HCC with the area under the receiver operating characteristic curve 0.975 (P < 0.01). The percentage of ILT4⁺CD1c⁺ subset was dramatically increased in tumor than that of TFL and blood. There were significant correlations between the percentage of ILT4⁺ in CD1c⁺ subset in tumor and that of in blood. The percentage of ILT4⁺CD1c⁺ subset in tumor tissue was strongly associated with the Edmondson-Steiner stage in HCC (P = 0.03). Furthermore, the capacity of ILT4⁺CD1c⁺ subset producing IFN-γ was lower than ILT4^- CD1c subset in PBMC of HCC patients following Poly I:C stimulation. Taken together, the increased ILT4⁺CD1c⁺ subset in tumor tissue might play an important role in immune suppression for patients with HCC.

Harnessing the innate immune system and local immunological microenvironment to treat colorectal cancer

Significant progress in the development of new immunotherapies has led to successful clinical trials for malignant melanoma and non-small cell lung cancer; however, for the majority of solid tumours of the gastrointestinal tract, little or no progress has been seen. The efficacy of immunotherapies is limited by the complexities of a diverse set of immune cells, and interactions between the tumour cells and all other cells in the local microenvironment of solid tumours. A large fraction of immune cells present in and around solid tumours derive from the innate arm of the immune system and using these cells against tumours offers an alternative immunotherapeutic option, especially as current strategies largely harness the adaptive arm of the immune system. This option is currently being investigated and attempts at using the innate immune system for gastrointestinal cancers are showing initial results. Several important factors, including cytokines, chemotherapeutics and the microbiome, influence the plasticity and functionality of innate (myeloid) cells in the microenvironment, and this complexity of regulation has limited translation into successful trials so far. In this review, current concepts of the immunobiology of the innate arm in the tumour microenvironment are presented in the context of clinical translation.

Using Dendritic Cell-Based Immunotherapy to Treat HIV: How Can This Strategy be Improved?

Harnessing dendritic cells (DC) to treat HIV infection is considered a key strategy to improve anti-HIV treatment and promote the discovery of functional or sterilizing cures. Although this strategy represents a promising approach, the results of currently published trials suggest that opportunities to optimize its performance still exist. In addition to the genetic and clinical characteristics of patients, the efficacy of DC-based immunotherapy depends on the quality of the vaccine product, which is composed of precursor-derived DC and an antigen for pulsing. Here, we focus on some factors that can interfere with vaccine production and should thus be considered to improve DC-based immunotherapy for HIV infection.

Tumor-Derived Microvesicles Enhance Cross-Processing Ability of Clinical Grade Dendritic Cells

Tumor cells release extracellular microvesicles (MVs) in the microenvironment to deliver biological signals to neighboring cells as well as to cells in distant tissues. Tumor-derived MVs appear to play contradictory role promoting both immunosuppression and tumor growth and both evoking tumor specific immune response. Recent evidences indicate that tumor-derived MVs can positively impact Dendritic Cells (DCs) immunogenicity by reprogramming DC antigen processing machinery and intracellular signaling pathways, thus promoting anti-tumor response. DCs are considered pivot cells of the immune system due to their exclusive ability to coordinate the innate and acquired immune responses, cross-present exogenous antigens, and prime naïve T cells. DCs are required for the induction and maintenance of long-lasting anti-tumor immunity and their exploitation has been extensively investigated for the design of anti-tumor vaccines. However, the clinical grade culture conditions that are required to generate DCs for therapeutic use can strongly affect their functions. Here, we investigated the immunomodulatory impact of MVs carrying the MUC1 tumor glycoantigen (MVs_MUC1) as immunogen formulation on clinical grade DCs grown in X-VIVO 15 (X-DCs). Results indicated that X-DCs displayed reduced performance of the antigen processing machinery in term of diminished phagocytosis and acidification of the phagosomal compartment suggesting an altered immunogenicity of clinical grade DCs. Pulsing DCs with MVs_MUC1 restored phagosomal alkalinization, triggering ROS increase. This was not observed when a soluble MUC1 protein was employed (rMUC1). Concurrently, MVs_MUC1 internalization by X-DCs allowed MUC1 cross-processing. Most importantly, MVs_MUC1 pulsed DCs activated IFNγ response mediated by MUC1 specific CD8⁺ T cells. These results strongly support the employment of tumor-derived MVs as immunogen platforms for the implementation of DC-based vaccines.

Microenvironmental derived factors modulating dendritic cell function and vaccine efficacy: the effect of prostanoid receptor and nuclear receptor ligands

Dendritic cells (DCs) are widely used in DC-based immunotherapies because of their capacity to steer immune responses. So far treatment success is limited and more functional knowledge on how DCs initiate and stably drive specific responses is needed. Many intrinsic and extrinsic factors contribute to how DCs skew the immune response towards immunity or tolerance. The origin and type of DC, its maturation status, but also factors they encounter in the in vitro or in vivo microenvironment they reside in during differentiation and maturation affect this balance. Treatment success of DC vaccines will, therefore, also depend on the presence of these factors during the process of vaccination. Identification and further knowledge of natural and pharmacological compounds that modulate DC differentiation and function towards a specific response may help to improve current DC-based immunotherapies. This review focuses on factors that could improve the efficacy of DC vaccines in (pre-)clinical studies to enhance DC-based immunotherapy, with a particular emphasis on compounds acting on prostanoid or nuclear receptor families.

Immune Curbing of Cancer Stem Cells by CTLs Directed to NANOG

Cancer stem cells (CSCs) have been identified as the source of tumor growth and disease recurrence. Eradication of CSCs is thus essential to achieve durable responses, but CSCs are resistant to current anti-tumor therapies. Novel therapeutic approaches that specifically target CSCs will, therefore, be crucial to improve patient outcome. Immunotherapies, which boost the body's own immune system to eliminate cancerous cells, could be an alternative approach to target CSCs. Vaccines of dendritic cells (DCs) loaded with tumor antigens can evoke highly specific anti-tumor T cell responses. Importantly, DC vaccination also promotes immunological memory formation, paving the way for long-term cancer control. Here, we propose a DC vaccination that specifically targets CSCs. DCs loaded with NANOG peptides, a protein required for maintaining stem cell properties, could evoke a potent anti-tumor immune response against CSCs. We hypothesize that the resulting immunological memory will also control newly formed CSCs, thereby preventing disease recurrence.

An immunological perspective for preventing cancer with berries

Berries and their phytochemicals have well documented chemopreventive roles, but understanding their ability to regulate cancer immunology is only beginning to be explored. The literature, including human studies, suggests that berry components can modulate our immune system to delay cancer development. Moreover, their wide spectrum of phytochemicals suggests that they might influence the functions of multiple immune cells and different aspects of cancer immunity. Cancer immune-therapies are showing promise for some types of cancer because they boost T cells' ability to recognize tumor cells - an essential prelude to destruction. Recognition occurs after dendritic cells present antigen, such as tumor antigen, to T cells, generating an adaptive response. Therefore, the potential of berries to aid cancer immune-therapies by, for example, regulating dendritic cells, warrants further investigation in animal and human studies. More information is also needed about berries' effects on the entire spectrum of immunity so that a comprehensive view can inform efforts to use berries to enhance immune responses during cancer prevention and treatment. This review summarizes the effects of berries as anti-tumor agents from the immunological perspective in tumor-bearing animals and humans.