Combined TLR2/4-activated dendritic/tumor cell fusions induce augmented cytotoxic T lymphocytes

Radiofrequency hyperthermia enhances the effect of OK-432 for Hepatocellular carcinoma by activating of TLR4-cGAS-STING pathway

Radiofrequency ablation (RFA) has been used as an alternative to surgical management of early-stage hepatocellular carcinoma (HCC). However, when large and irregular HCCs are subjected to RFA, a safety margin is usually difficult to obtain, thus causing a sublethal radiofrequency hyperthermia (RFH) at the ablated tumor margin. This study investigated the feasibility of using RFH to enhance the effect of OK-432 on HCC, with the aim to generate a tumor-free margin during RFA of HCC. Our results showed OK-432 could activate the cGAS-STING pathway, and RFH could further enhance the activation. Meanwhile, RFH could induce a high expression of TLR4, and TLR4 might be an upstream molecular of the cGAS-STING pathway. The combined therapy of RFH with OK-432 resulted in a better tumor response, and a prolonged survival compared to the other three treatments. In conclusion, RFH in combination with OK-432 might reduce the residual and recurrent tumor after RFA of large and irregular HCCs, and serve as a new option for other solid malignancies treated by RFA.

Plants against cancer: the immune-boosting herbal microbiome: not of the plant, but in the plant. Basic concepts, introduction, and future resource for vaccine adjuvant discovery

The presence of microorganism communities (MOCs) comprised of bacteria, fungi, archaea, algae, protozoa, viruses, and the like, are ubiquitous in all living tissue, including plant and animal. MOCs play a significant role in establishing innate and acquired immunity, thereby influencing susceptibility and resistance to disease. This understanding has fostered substantial advancements in several fields such as agriculture, food science/safety, and the development of vaccines/adjuvants, which rely on administering inactivated-attenuated MOC pathogens. Historical evidence dating back to the 1800s, including reports by Drs Busch, Coley, and Fehleisen, suggested that acute febrile infection in response to "specific microbes" could trigger spontaneous tumor remission in humans. This discovery led to the purposeful administration of the same attenuated strains, known as "Coley's toxin," marking the onset of the first microbial (pathogen) associated molecular pattern (MAMPs or PAMPs)-based tumor immunotherapy, used clinically for over four decades. Today, these same MAMPS are consumed orally by billions of consumers around the globe, through "specific" mediums (immune boosting "herbal supplements") as carriers of highly concentrated MOCs accrued in roots, barks, hulls, sea algae, and seeds. The American Herbal Products Association (AHPA) mandates microbial reduction in botanical product processing but does not necessitate the removal of dead MAMP laden microbial debris, which we ingest. Moreover, while existing research has focused on the immune-modulating role of plant phytochemicals, the actual immune-boosting properties might instead reside solely in the plant's MOC MAMP laden biomass. This assertion is logical, considering that antigenic immune-provoking epitopes, not phytochemicals, are known to stimulate immune response. This review explores a neglected area of research regarding the immune-boosting effects of the herbal microbiome - a presence which is indirectly corroborated by various peripheral fields of study and poses a fundamental question: Given that food safety focuses on the elimination of harmful pathogens and crop science acknowledges the existence of plant microbiomes, what precisely are the immune effects of ingesting MAMPs of diverse structural composition and concentration, and where are these distributed in our botanicals? We will discuss the topic of concentrated edible MAMPs as acid and thermally stable motifs found in specific herbs and how these would activate cognate pattern recognition receptors (PPRs) in the upper gut-associated lymphoid tissue (GALT), including Peyer's patches and the lamina propria, to boost antibody titers, CD8+ and CD4+ T cells, NK activity, hematopoiesis, and facilitating M2 to M1 macrophage phenotype transition in a similar manner as vaccines. This new knowledge could pave the way for developing bioreactor-grown/heat-inactivated MOC therapies to boost human immunity against infections and improve tumor surveillance.

Cell membrane-coated nanoparticles: a novel multifunctional biomimetic drug delivery system

Recently, nanoparticle-based drug delivery systems have been widely used for the treatment, prevention, and detection of diseases. Improving the targeted delivery ability of nanoparticles has emerged as a critical issue that must be addressed as soon as possible. The bionic cell membrane coating technology has become a novel concept for the design of nanoparticles. The diverse biological roles of cell membrane surface proteins endow nanoparticles with several functions, such as immune escape, long circulation time, and targeted delivery; therefore, these proteins are being extensively studied in the fields of drug delivery, detoxification, and cancer treatment. Furthermore, hybrid cell membrane-coated nanoparticles enhance the beneficial effects of monotypic cell membranes, resulting in multifunctional and efficient delivery carriers. This review focuses on the synthesis, development, and application of the cell membrane coating technology and discusses the function and mechanism of monotypic/hybrid cell membrane-modified nanoparticles in detail. Moreover, it summarizes the applications of cell membranes from different sources and discusses the challenges that may be faced during the clinical application of bionic carriers, including their production, mechanism, and quality control. We hope this review will attract more scholars toward bionic cell membrane carriers and provide certain ideas and directions for solving the existing problems.

The stimulatory effect of fusobacteria on dendritic cells under aerobic or anaerobic conditions

Fusobacteria have been suspected to be pathobionts of colon cancer and inflammatory bowel disease. However, the immunomodulatory properties that affect these inflammatory reactions in dendritic cells (DCs) under anaerobic and aerobic conditions have not yet been characterized. We directly assessed the stimulatory effects of anaerobic commensal bacteria, including fusobacteria, on a human DC line through coculture under aerobic or anaerobic conditions. Under aerobic or anaerobic conditions, stimulation of the DC line with all live commensal bacteria examined, except the probiotic Lactobacillus delbrueckii subsp. bulgaricus (L. bulgaricus), significantly increased the geometric mean fluorescent intensity (MFI) of marker proteins (HLA-ABC, HLA-DR, CD80, CD86, CD83, or CCR7) on the DC surface. In particular, both Fusobacterium nucleatum (F. nucleatum) and Escherichia coli (E. coli) significantly increased the expression of DC-associated molecules, except for CD83 under both aerobic and anaerobic conditions. The DC line stimulated with Fusobacterium varium (F. varium) significantly increased only CD80, HLA-ABC, and HLA-DR expression under anaerobic conditions. Moreover, differences in the levels of proinflammatory cytokines, such as IL-6, IL-8, and TNF-α, were detected in the DC line stimulated by all live commensal bacteria under either aerobic or anaerobic conditions. Under aerobic conditions, the DC line stimulated with E. coli produced significantly more IL-6, IL-8, and TNF-α than did the cells stimulated with any of the bacteria examined. When E. coli were used to stimulate the DC line under anaerobic conditions, TNF-α was predominantly produced compared to stimulation with any other bacteria. Compared to the DC line stimulated with any other bacteria, the cells stimulated with F. nucleatum showed significantly increased production of IL-6, IL-8 and TNF-α only under anaerobic conditions. In particular, E. coli, F. nucleatum, and F. varium strongly stimulated the DC line, resulting in significantly increased expression of surface molecules associated with DCs and production of inflammatory cytokines.

Trametes versicolor (Synn. Coriolus versicolor) Polysaccharides in Cancer Therapy: Targets and Efficacy

Coriolus versicolor (L.) Quél. is a higher fungi or mushroom which is now known by its accepted scientific name as Trametes versicolor (L.) Lloyd (family Polyporaceae). The polysaccharides, primarily two commercial products from China and Japan as PSP and PSK, respectively, have been claimed to serve as adjuvant therapy for cancer. In this paper, research advances in this field, including direct cytotoxicity in cancer cells and immunostimulatory effects, are scrutinised at three levels: in vitro, in vivo and clinical outcomes. The level of activity in the various cancers, key targets (both in cancer and immune cells) and pharmacological efficacies are discussed.

Immunotherapy for Gastric Cancer: Time for a Personalized Approach?

Over the last decade, our understanding of the mechanisms underlying immune modulation has greatly improved, allowing for the development of multiple therapeutic approaches that are revolutionizing the treatment of cancer. Immunotherapy for gastric cancer (GC) is still in the early phases but is rapidly evolving. Recently, multi-platform molecular analyses of GC have proposed a new classification of this heterogeneous group of tumors, highlighting subset-specific features that may more reliably inform therapeutic choices, including the use of new immunotherapeutic drugs. The clinical benefit and improved survival observed in GC patients treated with immunotherapeutic strategies and their combination with conventional therapies highlighted the importance of the immune environment surrounding the tumor. A thorough investigation of the tumor microenvironment and the complex and dynamic interaction between immune cells and tumor cells is a fundamental requirement for the rational design of novel and more effective immunotherapeutic approaches. This review summarizes the pre-clinical and clinical results obtained so far with immunomodulatory and immunotherapeutic treatments for GC and discusses the novel combination strategies that are being investigated to improve the personalization and efficacy of GC immunotherapy.

Dendritic-Tumor Fusion Cell-Based Cancer Vaccines

Dendritic cells (DCs) are potent antigen-presenting cells (APCs) that play a critical role in the induction of antitumor immunity. Therefore, various strategies have been developed to deliver tumor-associated antigens (TAAs) to DCs as cancer vaccines. The fusion of DCs and whole tumor cells to generate DC-tumor fusion cells (DC-tumor FCs) is an alternative strategy to treat cancer patients. The cell fusion method allows DCs to be exposed to the broad array of TAAs originally expressed by whole tumor cells. DCs then process TAAs endogenously and present them through major histocompatibility complex (MHC) class I and II pathways in the context of costimulatory molecules, resulting in simultaneous activation of both CD4⁺ and CD8⁺ T cells. DC-tumor FCs require optimized enhanced immunogenicity of both DCs and whole tumor cells. In this context, an effective fusion strategy also needs to produce immunogenic DC-tumor FCs. We discuss the potential ability of DC-tumor FCs and the recent progress in improving clinical outcomes by DC-tumor FC-based cancer vaccines.

Herbal preparation (HemoHIM) enhanced functional maturation of bone marrow-derived dendritic cells mediated toll-like receptor 4

Background

HemoHIM, which is an herbal preparation of three edible herbs (Angelicam gigas Nakai, Cnidium offinale Makino, and Peaonia japonica Miyabe), is known to have various biological and immunological activities, but the modulatory effects of this preparation on dendritic cells (DCs)-mediated immune responses have not been examined previously. DCs are a unique group of white blood cells that initiate primary immune responses by capturing, processing, and presenting antigens to T cells.

Results

In the present study, we investigated the effect of HemoHIM on the functional and phenotypic maturation of murine bone marrow-derived dendritic cells (BMDCs) both in vitro and in vivo. The expression of co-stimulatory molecules (CD40, CD80, CD86, MHC I, and MHC II) and the production of cytokines (IL-1β, IL-6, IL-12p70, and TNF-α) were increased by HemoHIM in BMDCs. Furthermore, the antigen-uptake ability of BMDCs was decreased by HemoHIM, and the antigen-presenting ability of HemoHIM-treated mature BMDCs increased TLR4-dependent CD4⁺ and CD8⁺ T cell responses.

Conclusions

Our findings demonstrated that HemoHIM induces TLR4-mediated BMDCs functional and phenotypic maturation through in vivo and in vitro. And our study showed the antigen-presenting ability that HemoHIM-treated mature BMDCs increase CD4⁺ and CD8⁺ T cell responses by in vitro. These results suggest that HemoHIM has the potential to mediate DC immune responses.

Acute myeloid leukaemia-derived Langerhans-like cells enhance Th1 polarization upon TLR2 engagement

Langerhans cells (LCs) represent a highly specialized subset of epidermal dendritic cells (DCs), yet not fully understood in their function of balancing skin immunity. Here, we investigated in vitro generated Langerhans-like cells obtained from the human acute myeloid leukaemia cell line MUTZ-3 (MUTZ-LCs) to study TLR- and cytokine-dependent activation of epidermal DCs. MUTZ-LCs revealed high TLR2 expression and responded robustly to TLR2 engagement, confirmed by increased CD83, CD86, PD-L1 and IDO expression, upregulated IL-6, IL-12p40 and IL-23p19 mRNA levels IL-8 release. TLR2 activation reduced CCR6 and elevated CCR7 mRNA expression and induced migration of MUTZ-LCs towards CCL21. Similar results were obtained by stimulation with pro-inflammatory cytokines TNF-α and IL-1β whereas ligands of TLR3 and TLR4 failed to induce a fully mature phenotype. Despite limited cytokine gene expression and production for TLR2-activated MUTZ-LCs, co-culture with naive CD4(+) T cells led to significantly increased IFN-γ and IL-22 levels indicating Th1 differentiation independent of IL-12. TLR2-mediated effects were blocked by the putative TLR2/1 antagonist CU-CPT22, however, no selectivity for either TLR2/1 or TLR2/6 was observed. Computer-aided docking studies confirmed non-selective binding of the TLR2 antagonist. Taken together, our results indicate a critical role for TLR2 signalling in MUTZ-LCs considering the leukemic origin of the generated Langerhans-like cells.

The impact of dendritic cell-tumor fusion cells on cancer vaccines - past progress and future strategies

Dendritic cells (DCs) are potent antigen-presenting cells that can be used in cancer vaccines. Thus, various strategies have been developed to deliver tumor-associated antigens via DCs. One strategy includes administering DC-tumor fusion cells (DC-tumor FCs) to induce antitumor immune responses in cancer patients. However, clinical trials using this strategy have fallen short of expectations. Several factors might limit the efficacy of these anticancer vaccines. To induce efficient antitumor immune responses and enhance potential clinical benefits, DC-tumor FC-based cancer vaccines require manipulations that improve immunogenicity for both DCs and whole tumor cells. This review addresses recent progress in improving clinical outcomes using DC-tumor FC-based cancer vaccines.

Personalized approaches to active immunotherapy in cancer

Immunotherapy is emerging as a promising anti-cancer curative modality. However, in contrast to recent advances obtained employing checkpoint blockade agents and T cell therapies, clinical efficacy of therapeutic cancer vaccines is still limited. Most vaccination attempts in the clinic represent "off-the shelf" approaches since they target common "self" tumor antigens, shared among different patients. In contrast, personalized approaches of vaccination are tailor-made for each patient and in spite being laborious, hold great potential. Recent technical advancement enabled the first steps in the clinic of personalized vaccines that target patient-specific mutated neo-antigens. Such vaccines could induce enhanced tumor-specific immune response since neo-antigens are mutation-derived antigens that can be recognized by high affinity T cells, not limited by central tolerance. Alternatively, the use of personalized vaccines based on whole autologous tumor cells, overcome the need for the identification of specific tumor antigens. Whole autologous tumor cells could be administered alone, pulsed on dendritic cells as lysate, DNA, RNA or delivered to dendritic cells in-vivo through encapsulation in nanoparticle vehicles. Such vaccines may provide a source for the full repertoire of the patient-specific tumor antigens, including its private neo-antigens. Furthermore, combining next-generation personalized vaccination with other immunotherapy modalities might be the key for achieving significant therapeutic outcome.

Cell fusion between dendritic cells and whole tumor cells

We have developed cell fusion vaccines generated with dendritic cells (DCs) and whole tumor cells to induce antigen-specific antitumor immunity. This approach allows DCs to be exposed to the entire repertoire of tumor-associated antigens (TAAs) originally expressed by the tumor cell, to process them endogenously, and to present antigenic epitopes thought the MHC class I and class II pathways to activate both CD8+ and CD4+ T cells, respectively. The therapeutic efficacy of DC/tumor fusion cell vaccines requires the improved immunogenicity of both cells. Here, we describe the strategy to generate DC/tumor fusion cells.

Composite peptide-based vaccines for cancer immunotherapy (Review)

The use of peptide-based vaccines as therapeutics aims to elicit immune responses through antigenic epitopes derived from tumor antigens. Peptide-based vaccines are easily synthesized and chemically stable entities, and of note, they are absent of oncogenic potential. However, their application is more complicated as the success of an effective peptide-based vaccine is determined by numerous parameters. The success thus far has been limited by the choice of tumor antigenic peptides, poor immunogenicity and incorporation of strategies to reverse cancer-mediated immune suppression. In the present review, an overview of the mechanisms of peptide-based vaccines is provided and antigenic peptides are categorized with respect to their tissue distribution in order to determine their usefulness as targets. Furthermore, certain approaches are proposed that induce and maintain T cells for immunotherapy. The recent progress indicates that peptide-based vaccines are preferential for targeted therapy in cancer patients.

Fusions between dendritic cells and whole tumor cells as anticancer vaccines

Various strategies have been developed to deliver tumor-associated antigens (TAAs) to dendritic cells (DCs). Among these, the fusion of DCs and whole cancer cells can process a broad array of TAAs, including hitherto unidentified molecules, and present them in complex with MHC Class I and II molecules and in the context of co-stimulatory signals. DC-cancer cell fusions have been shown to stimulate potent antitumor immune responses in animal models. In early clinical trials, however, the antitumor effects of DC-cancer cell fusions are not as vigorous as in preclinical settings. This mini-review summarizes recent advances in anticancer vaccines based on DC-cancer cell fusions.

Induction of antigen-specific cytotoxic T lymphocytes by fusion cells generated from allogeneic plasmacytoid dendritic and tumor cells

Previous work has demonstrated that fusion cells generated from autologous monocyte-derived dendritic cells (MoDCs) and whole tumor cells induce efficient antigen-specific cytotoxic T lymphocytes. A major limitation to the use of this strategy is the availability of adequate amounts of autologous tumor cells. Moreover, MoDCs from cancer patients are often defective in their antigen-processing and presentation machinery. In this study, two types of allogeneic cells, a leukemia plasmacytoid dendritic cell (pDC) line (PMDC05) and pancreatic cancer cell lines (PANC-1 or MIA PaCa-2), were fused instead of autologous MoDCs and tumor cells. We created four types of pDC/tumor fusion cells by alternating fusion partners and treating with lipopolysaccharide (LPS): i) PMDC05 fused with PANC-1 (pDC/PANC-1), ii) PMDC05 fused with MIA PaCa-2 (pDC/MIA PaCa-2), iii) LPS-stimulated pDC/PANC-1 (LPS-pDC/PANC-1) and iv) LPS-stimulated pDC/MIA PaCa-2 (LPS-pDC/MIA PaCa-2) and examined their antitumor immune responses. The LPS-pDC/tumor cell fusions were the most active, as demonstrated by their: i) upregulated expression of HLA-DR and CD86 on a per-fusion-cell basis, ii) increased production of IL-12p70, iii) generation of a higher percentage of IFN-γ-producing CD4⁺ and CD8⁺ T cells and iv) augmented induction of MUC1-specific CD8⁺ T cells that lyse target tumor cells. This study provides the first evidence for an in vitro induction of antigen-specific cytotoxic T lymphocytes by LPS-stimulated fusion cells generated from leukemia plasmacytoid DCs and tumor cells and suggests that this strategy has potential applicability to the field of adoptive immunotherapy.

Size-dependent effects of gold nanoparticles uptake on maturation and antitumor functions of human dendritic cells in vitro

Gold nanoparticles (GNPs) are claimed as outstanding biomedical tools for cancer diagnostics and photo-thermal therapy, but without enough evidence on their potentially adverse immunological effects. Using a model of human dendritic cells (DCs), we showed that 10 nm- and 50 nm-sized GNPs (GNP₁₀ and GNP₅₀, respectively) were internalized predominantly via dynamin-dependent mechanisms, and they both impaired LPS-induced maturation and allostimulatory capacity of DCs, although the effect of GNP₁₀ was more prominent. However, GNP₁₀ inhibited LPS-induced production of IL-12p70 by DCs, and potentiated their Th2 polarization capacity, while GNP₅₀ promoted Th17 polarization. Such effects of GNP₁₀ correlated with a stronger inhibition of LPS-induced changes in Ca²⁺ oscillations, their higher number per DC, and more frequent extra-endosomal localization, as judged by live-cell imaging, proton, and electron microscopy, respectively. Even when released from heat-killed necrotic HEp-2 cells, GNP₁₀ inhibited the necrotic tumor cell-induced maturation and functions of DCs, potentiated their Th2/Th17 polarization capacity, and thus, impaired the DCs' capacity to induce T cell-mediated anti-tumor cytotoxicity in vitro. Therefore, GNP₁₀ could potentially induce more adverse DC-mediated immunological effects, compared to GNP₅₀.

The mannose-sensitive hemagglutination pilus strain of Pseudomonas aeruginosa shift peritoneal milky spot macrophages towards an M1 phenotype to dampen peritoneal dissemination

Peritoneal dissemination (PD) of tumor cells is the most frequent pattern of gastric cancer recurrence and the leading cause of death. Peritoneal milky spots are deemed as the site of origin of gastric cancer PD wherein the main cellular components are macrophages. A vaccine derived from the mannose-sensitive hemagglutination pilus strain of Pseudomonas aeruginosa (PA-MSHA) has exhibit strong immune modulatory properties. In the present study, we tested the hypothesis whether the PA-MSHA vaccine activated peritoneal milky spot macrophages (PMSM) in a manner that would attenuate PD. It was observed that PA-MSHA activated PMSM towards a classical activation phenotype via a toll-like receptor4/9-dependent mechanism, which increased interleukin-12 levels and promoted the expression of co-stimulatory and antigen-presenting molecules like CD80, CD86, and MHC-II (P < 0.05). In addition, PA-MSHA-treated PMSM exhibited strong nonspecific antitumor effects in both contact-dependent and contact-independent modes of action (P < 0.05). In mice treated with PA-MSHA before inoculating gastric cancer cells, we noted alleviated PD toward the untreated mice. In conclusion, our findings demonstrated that PA-MSHA can stimulate PMSM towards an M1 phenotype and that activated PMSM inhibit gastric cancer growth and PD both in vitro and in vivo. The results of the current study provide a mechanistic insight that is relevant to the potential application of PA-MSHA in the treatment of gastric cancer-mediated PD.

Strategies to improve the immunogenicity of anticancer vaccines based on dendritic cell/malignant cell fusions

The rationale for fusing dendritic cells (DCs) with whole tumor cells to generate anticancer vaccines resides in the fact that the former operate as potent antigen-presenting cells, whereas the latter express a constellation of tumor-associated antigens (TAAs). Although the administration of DC/malignant cell fusions to cancer patients is safe and this immunotherapeutic intervention triggers efficient tumor-specific T-cell responses in vitro, a limited number of objective clinical responses to DC/cancer cell fusions has been reported thus far. This review discusses novel approaches to improve the immunogenicity of DC/malignant cell fusions as anticancer vaccines.

Low immunogenicity of neural progenitor cells differentiated from induced pluripotent stem cells derived from less immunogenic somatic cells

The groundbreaking discovery of induced pluripotent stem cells (iPS cells) provides a new source for cell therapy. However, whether the iPS derived functional lineages from different cell origins have different immunogenicity remains unknown. It had been known that the cells isolated from extra-embryonic tissues, such as umbilical cord mesenchymal cells (UMCs), are less immunogenic than other adult lineages such as skin fibroblasts (SFs). In this report, we differentiated iPS cells from human UMCs and SFs into neural progenitor cells (NPCs) and analyzed their immunogenicity. Through co-culture with allologous peripheral blood mononuclear cells (PBMCs), we showed that UMCs were indeed less immunogenic than skin cells to simulate proliferation of PBMCs. Surprisingly, we found that the NPCs differentiated from UMC-iPS cells retained low immunogenicity as the parental UMCs based on the PBMC proliferation assay. In cytotoxic expression assay, reactions in most kinds of immune effector cells showed more perforin and granzyme B expression with SF-NPCs stimulation than that with UMC-NPCs stimulation in PBMC co-culture system, in T cell co-culture system as well. Furthermore, through whole genome expression microarray analysis, we showed that over 70 immune genes, including all members of HLA-I, were expressed at lower levels in NPCs derived from UMC-iPS cells than that from SF-iPS cells. Our results demonstrated a phenomenon that the low immunogenicity of the less immunogenic cells could be retained after cell reprogramming and further differentiation, thus provide a new concept to generate functional lineages with lower immunogenicity for regenerative medicine.

Improved immunogenicity of fusions between ethanol-treated cancer cells and dendritic cells exposed to dual TLR stimulation

Tumor-derived transforming growth factor β1 (TGFβ1) generally abrogates the immunogenicity of dendritic cells (DCs) fused to whole cancer cells. We have recently revealed that ethanol-treated neoplastic cells fused to DCs exposed to 2 Toll-like receptor agonists efficiently induce cytotoxic T lymphocytes via TGFβ1 blockade and the production of interleukin-12.

Augmentation of antitumor immunity by fusions of ethanol-treated tumor cells and dendritic cells stimulated via dual TLRs through TGF-β1 blockade and IL-12p70 production

The therapeutic efficacy of fusion cell (FC)-based cancer vaccine generated with whole tumor cells and dendritic cells (DCs) requires the improved immunogenicity of both cells. Treatment of whole tumor cells with ethanol resulted in blockade of immune-suppressive soluble factors such as transforming growth factor (TGF)-β1, vascular endothelial growth factor, and IL-10 without decreased expression of major histocompatibility complex (MHC) class I and the MUC1 tumor-associated antigen. Moreover, the ethanol-treated tumor cells expressed “eat-me” signals such as calreticulin (CRT) on the cell surface and released immunostimulatory factors such as heat shock protein (HSP)90α and high-mobility group box 1 (HMGB1). A dual stimulation of protein-bound polysaccharides isolated from Coriolus versicolor (TLR2 agonist) and penicillin-inactivated Streptococcus pyogenes (TLR4 agonist) led human monocyte-derived DCs to produce HSP90α and multiple cytokines such as IL-12p70 and IL-10. Interestingly, incorporating ethanol-treated tumor cells and TLRs-stimulated DCs during the fusion process promoted fusion efficiency and up-regulated MHC class II molecules on a per fusion basis. Moreover, fusions of ethanol-treated tumor cells and dual TLRs-stimulated DCs (E-tumor/FCs) inhibited the production of multiple immune-suppressive soluble factors including TGF-β1 and up-regulated the production of IL-12p70 and HSP90α. Most importantly, E-tumor/FCs activated T cells capable of producing high levels of IFN-γ, resulting in augmented MUC1-specific CTL induction. Collectively, our results illustrate the synergy between ethanol-treated whole tumor cells and dual TLRs-stimulated DCs in inducing augmented CTL responses in vitro by FC preparations. The alternative system is simple and may provide a platform for adoptive immunotherapy.

The combination of TLR2 and TLR4 agonists promotes the immunogenicity of dendritic cell/cancer cell fusions

The induction of antitumor immune responses by dendritic cell (DC)/tumor cell fusions can be modulated by their activation status. Our recent work reveals that the combination of Toll-like receptor 2 (TLR2) and TLR4 agonists promotes the immunogenicity of DC/tumor cell fusions, allowing them to overcome the immunosuppressive effects of transforming growth factor β1.