Cancer vaccines based on dendritic cells loaded with tumor-associated antigens

Dendritic cells (DCs) can be used as an antigen presentation platform for vaccination against cancer. In this approach, DCs are expanded in vitro from monocyte-derived progenitors, and subsequently loaded with well-characterized tumor-associated antigens (TAAs). TAAs can be incubated with DCs in various forms, including peptides, recombinant proteins, plasmid DNA, formulated RNA, or recombinant viruses. Advantages and limitations of DC-based cellular vaccines against cancers, as well as preliminary results of clinical studies already performed in humans, are discussed. Importantly, significant advances in our understanding of the biology of DCs can be used to support the design of new vaccines or adjuvants in order to elicit T_H1 cellular immune responses. This revised version was published online in July 2006 with corrections to the Cover Date.     

Dendritic cells: Potential role in cancer therapy

Dendritic cells (DC) are extremely potent antigen presenting cells, uniquely capable of sensitizing naive T cells to protein antigens and eliciting antigen specific immune responses. Studies of human DC isolated from peripheral blood indicate that these cells can be used to stimulate and expand antigen specific CD4+ and CD8+ T cells, in vitro. On the basis of these findings we have initiated pilot clinical studies to investigate the ability of DC pulsed ex vivo with tumor associated proteins to stimulate host anti-tumor immunity when re-infused as a vaccine. In the first such study DC pulsed with tumor derived idiotype protein were infused into patients with low grade malignant B cell lymphoma who had failed conventional chemotherapy. The majority of treated patients developed T cell mediated anti-idiotype immune responses and some of the patients experienced tumor regression. These results suggest that DC based immunotherapy is a potentially useful approach to B cell lymphoma and raises the possibility that the approach may prove useful in the treatment of other tumors as well. This revised version was published online in June 2006 with corrections to the Cover Date.     

Skewing effect of sulprostone on dendritic cell maturation compared with dinoprostone

Background

Dendritic cells (DCs) are the most efficient antigen-presenting cells and act at the center of the immune system owing to their ability to control both immune tolerance and immunity. In cancer immunotherapy, DCs play a key role in the regulation of the immune response against tumors and can be generated ex vivo with different cytokine cocktails. Methods. We evaluated the feasibility of dinoprostone (PGE₂) replacement with the molecular analog sulprostone, in our good manufacturing practice (GMP) protocol for the generation of DC-based cancer vaccine. We characterized the phenotype and the function of DCs matured in the presence of sulprostone as a potential substitute of dinoprostone in the pro-inflammatory maturation cocktail consisting of tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β) and IL-6. Results. We found that sulprostone invariably reduces the recovery, but does not significantly modify the viability and the purity of DCs. The presence of sulprostone in the maturation cocktail increases the adhesion of single cells and of clusters of DCs to the flask, making them more similar to their immature counterpart in terms of adhesion and spreading proprieties. Moreover, we observed that sulprostone impairs the expression of co-stimulatory molecules and the spontaneous as well as the directed migration capacity of DCs.

Exploiting dendritic cells for cancer immunotherapy: genetic modification of dendritic cells

Dendritic cells (DCs) are pivotal regulators of immune reactivity and immune tolerance. The observation that DCs can recruit naive T cells has invigorated cancer immunology and led to the proposal of DCs as the basis for vaccines designed for the treatment of cancer. Designing effective strategies to load DCs with antigens is a challenging field of research. The successful realization of gene transfer to DCs will be highly dependent on the employed vector system. Here, we review various viral and non-viral gene transfer systems, and discuss their distinct characteristics and possible advantages and disadvantages in respect to their use in DC-based immunotherapy.     

From pathogen to medicine: HIV-1-derived lentiviral vectors as vehicles for dendritic cell based cancer immunotherapy

Over the years, the unique capacity of dendritic cells (DC) for efficient activation of naive T cells has led to their extensive use in cancer immunotherapy protocols. In order to be able to fulfil their role as antigen-presenting cells, the antigen of interest needs to be efficiently introduced and subsequently correctly processed and presented by the DC. For this purpose, a variety of both viral and non-viral antigen-delivery systems have been evaluated. Amongst those, HIV-1-derived lentiviral vectors have been used successfully to transduce DC.This review considers the use of HIV-1-derived lentiviral vectors to transduce human and murine DC for cancer immunotherapy. Lentivirally transduced DC have been shown to present antigenic peptides, prime transgene-specific T cells in vitro and elicit a protective cytotoxic T-lymphocyte (CTL) response in animal models. Different parameters determining the efficacy of transduction are considered. The influence of lentiviral transduction on the DC phenotype and function is described and the induction of immune responses by lentivirally transduced DC in vitro and in vivo is discussed in detail. In addition, direct in vivo administration of lentiviral vectors aiming at the induction of antigen-specific immunity is reviewed. This strategy might overcome the need for ex vivo generation and antigen loading of DC. Finally, future perspectives towards the use of lentiviral vectors in cancer immunotherapy are presented.     

Open-label,multi-center,non-randomized,single-arm study to evaluate the safety and efficacy of dendritic cell immunotherapy in patients with refractory solid malignancies,on supportive care

Background aimsA phase II clinical trial of an autologous dendritic cell (DC) formulation for the management of refractory solid malignant tumors was conducted across six sites in India with an objective to study safety and efficacy.MethodsA total of 51 patients with refractory cancer (either sex) with life expectancy ≥3 months, Eastern Cooperative Oncology Group score ≤2, available tumor tissue and adequate organ and bone marrow function were recruited. Monocytes obtained by leukapheresis, differentiated into DCs by cytokines and primed with autologous tumor lysate (fresh tissue biopsy or paraffin block). On the 8th day, mature DCs were analyzed for expression of CD40, CD80, CD83, CD86, DC205 and DC209. The treatment regime consisted of six doses (intravenous) over 14 weeks with 2 post-treatment follow-up visits, 6 weeks apart. Safety was assessed at all visits and responses were evaluated on days 58, 100 and 184 or at end of the study.ResultsA total of 38 patients were evaluated for safety and efficacy. One adverse event classified as possibly related was an episode of rigors or chills with mild pyrexia during one infusion. Objective response rate by Response Evaluation Criteria In Solid Tumors was 28.9% (11/38) and immune-related response criteria was 42.1% (16/38); 90% confidence interval for objective response rate was (17.2, 43.3) and (28.5, 56.7) by Response Evaluation Criteria In Solid Tumors and immune-related response criteria, respectively. The median time to treatment progression was >9 weeks. Median overall survival was 397 days. An increase in the expression of interferon-γ was not significant.ConclusionsTherapy was safe. The responses, time to treatment progression and survival are encouraging for patients with aggressive refractory disease.     

Allogeneic dendritic cell vaccination against metastatic renal cell carcinoma with or without cyclophosphamide

In this phase I/II study, we evaluated the feasibility, safety and efficacy of allogeneic dendritic cells (DCs) with or without cyclophosphamide in the treatment of patients with metastatic renal cell carcinoma (RCC). Immunomagnetic beads were used to isolate CD14⁺ monocytes from healthy donor leukapheresis products, and CD83⁺ antigen-pulsed monocyte-derived DCs (moDCs) loaded with tumor lysate and keyhole limpet hemocyanin (KLH) were generated. Twelve patients were treated with allogeneic moDCs alone, while ten patients also received cyclophosphamide on days 4 and 3 prior to vaccination. Of the 22 patients enrolled, 20 received full treatment consisting of at least three vaccinations at monthly intervals. Two mixed responses with substantial tumor regression were observed. In 3 patients, disease stabilization occurred, in 13 patients disease progressed and 4 patients were lost to follow-up. Overall, immune responses against KLH and tumor lysate were weak or absent; however, the strongest increases in antigen-independent and KLH-specific responses were observed in the 2 patients with mixed responses. In addition, 1 of them showed a substantial increase in oncofetal antigen (OFA)-specific IFN- production. Importantly, the 2 mixed responders and 1 patient with stable disease belonged to the cyclophosphamide group. Median overall survival in the cyclophosphamide group was 23.2 and 20.3 months in the group that received allogeneic moDCs alone. Allogeneic immunotherapy with moDCs is feasible and well tolerated. However, the immunogenicity of allogeneic moDCs is clearly less pronounced than that of autologous moDC immunotherapy. Cyclophosphamide may have the capacity to augment DC-induced antitumor immunity.     

肿瘤?鄄树突状细胞融合疫苗研究进展

树突状细胞(DC)是功能最强的专职抗原呈递细胞,在抗肿瘤免疫方面发挥着重要的作用．以DC为基础的肿瘤疫苗的研究发展迅速,其中效果最好的是DC/肿瘤融合细胞疫苗——不仅具有DC的抗原呈递功能,也持续产生内源性抗原肽．DC/肿瘤融合细胞疫苗不仅在动物实验中进行了大量的研究,而且已经进入了Ⅰ/Ⅱ期临床试验,结果表明,融合细胞能有效地诱导肿瘤特异性T淋巴细胞反应,病人也能很好地耐受．就DC/肿瘤融合疫苗的研究进展进行综述,并对目前研究中存在的问题作了客观的分析．     

Preparation of peptide-loaded dendritic cells for cancer immunotherapy

Dendritic cell-based vaccines are being evaluated in clinical trials to determine their ability to activate clinically relevant tumor antigen-specific immune responses. Although some groups isolate dendritic cells from peripheral blood, most have found it more efficient to generate large numbers from peripheral blood progenitors, particularly plastic adherent or CD14+ monocytes, in media supplemented with GM-CSF and IL-4. These DC may then be matured, if desired, and loaded with antigen, such as tumor-associated peptides, prior to administration. We describe the scheme that we are currently using to generate peptide-loaded dendritic cells for our clinical trials of cancer immunotherapy.     

Dendritic cell/cytokine-induced killer cell-based immunotherapy in lung cancer: What we know and future landscape

Multiple modalities for lung cancer therapy have emerged in the past decade, whereas their clinical applications and survival-beneficiary is little known. Vaccination with dendritic cells (DCs) or DCs/cytokine-induced killer (CIK) cells has shown limited success in the treatment of patients with advanced non-small-cell lung cancer. To evaluate and overcome these limitations in further studies, in the present review, we sum up recent progress about DCs or DCs/CIKs-based approaches for preclinical and clinical trials in patients with lung cancer and discuss some of the limited therapeutic success. Moreover, this review highlights the need to focus future studies on the development of new approaches for successful immunotherapy in patients with lung cancer.     

Plasma from some cancer patients inhibits adenoviral Ad5f35 vector transduction of dendritic cells

Background

Pooled AB serum is often used as a media supplement for cell culture but it has the potential to transmit infectious diseases. To avoid this risk, we used autologous plasma as a media supplement for manufacturing dendritic cells (DCs) for cancer immunotherapy. We noticed inconsistencies in the DCs and investigated their nature and cause.

Immune therapy of melanoma: Overview of therapeutic vaccines

Melanoma is the most serious type of skin cancer which develops from the occurrence of genetic mutations in the melanocytes. Based on the features of melanoma tumors such as location, genetic profile and stage, there are several therapeutic strategies including surgery, chemotherapy, and radiotherapy. However, because of the appearance resistance mechanisms, the efficiency of these treatments strategies may be reduced. It has been demonstrated that therapeutic monoclonal antibodies can improve the efficiency of melanoma therapies. Recently, several mAbs, such as nivolumab, pembrolizumab, and ipilimumab, were approved for the immunotherapy of melanoma. The antibodies inhibit immune checkpoint receptors such as CTL4 and pd-1. Another therapeutic strategy for the treatment of melanoma is cancer vaccines, which improve clinical outcomes in patients. The combination therapy using antibodies and gene vaccine give us a new perspective in the treatment of melanoma patients. Herein, we present the recent progressions in the melanoma immunotherapy, especially dendritic cells mRNA vaccines by reviewing recent literature.     

The immunostimulatory effects of retinoblastoma cell supernatant on dendritic cells

Dendritic cells (DCs) are crucial for the induction and maintenance of tumor-specific immune responses. Studies have shown that tumor-associated DCs are immunosuppressed in some human tumors. However, phenotype and function of DCs in retinoblastoma (RB) remain unclear. RB cell supernatant (RBcs) was used to treat DCs in vitro to explore the effect of RB cells on DCs. DCs were generated from peripheral blood mononuclear cells of healthy donors. On day 5 of culture, DCs were treated with RBcs for 24 h, and then purified using magnetic beads. The maturation of DCs was induced by TNF-α or LPS. After treatment with RBcs, expression of co-stimulatory molecules CD80 and CD86 was elevated in DCs, accompanied by increased production of IL-12p70, TNF-α, IL-6, IL-1β, and IL-8 but decreased production of IL-10. RBcs neither inhibited DC maturation nor promoted DC apoptosis. Moreover, RBcs-exposed DCs stimulated allogenetic T cell proliferation and T cell-derived cytokine production. These results indicate that RBcs can improve DCs’ antigen presenting function and capability to activate T cells, suggesting that RB cells may have an immunostimulatory effect on DCs, and Dcbased immunotherapy may be adopted in the treatment of RB.     

Hizikia fusiforme extract enhances dendritic cell maturation in vitro and in vivo

ABSTRACT

Dendritic cells (DCs) are play critical roles in the priming and regulation of immune responses. DCs rapidly process and convey these antigens to prime antigen-specific T cells. Therefore, regulation of DCs functions is important for immunity and immunotherapies. Immune adjuvants for DCs activation are needed to improve the efficacy of vaccines against tumors and many infectious diseases. Therefore, we demonstrate that H. fusiformis extract can regulate DCs maturation and activation. H. fusiformis extract induced costimulatory molecules (CD 80 and CD86), antigen-presenting molecules (major histocompatibility complex (MHC) I and II), CCR7 expression, and interleukin (IL)-12 production in DCs. These effects are associated with upregulation of mitogen-activated protein kinase (MAPK) signaling pathway. In addition, H. fusiformis extract induces costimulatory molecules on splenic DCs and activated CD8⁺ T cells in vivo. Taken together, these findings suggest that H. fusiformis extract may be a potential efficient immune therapeutic compound in DCs-mediated immunotherapies.     

Complex evaluation of human monocyte‐derived dendritic cells for cancer immunotherapy

Dendritic cell (DC) immunotherapy is capable of generating tumour‐specific immune responses. Different maturation strategies were previously tested to obtain DC capable of anti‐cancer responses in vitro, usually with limited clinical benefit. Mutual comparison of currently used maturation strategies and subsequent complex evaluation of DC functions and their stimulatory capacity on T cells was performed in this study to optimize the DC vaccination strategy for further clinical application. DC were generated from monocytes using granulocyte–macrophage colony‐stimulating factor (GM‐CSF) and interleukin (IL)‐4, pulsed with whole tumour cell lysate and then matured with one of five selected maturation strategies or cultured without additional maturation stimulus. DC were characterized with regard to their surface marker expression, cytokine profiles, migratory capacity, allogeneic and autologous T cell stimulatory capacity as well as their specific cytotoxicity against tumour antigens. We were able to demonstrate extensive variability among different maturation strategies currently used in DC immunotherapeutic protocols that may at least partially explain limited clinical benefit of some clinical trials with such DC. We identified DC matured with interferon‐γ and lipopolysaccharide as the most attractive candidate for future clinical trials in cancer immunotherapy.     

A single-cell surgery microfluidic device for transplanting tumor cytoplasm into dendritic cells without nuclei mixing

This study aimed to demonstrate the feasibility of generating tumor cell vaccine models by single-cell surgery in a microfluidic device that integrates one-to-one electrofusion, shear flow reseparation, and on-device culture. The device was microfabricated from polydimethylsiloxane (PDMS) and consisted of microorifices (aperture size: ∼3 μm) for one-to-one fusion, and microcages for on-device culture. Using the device, we could achieve one-to-one electrofusion of leukemic plasmacytoid dendritic cells (DC-like cells) and Jurkat cells with a fusion efficiency of ∼ 80%. Fusion via the narrow microorifices allowed DC-like cells to acquire cytoplasmic contents of the Jurkat cells while preventing nuclei mixing. After fusion, the DC-like cells were selectively reseparated from the Jurkat cells by shear flow application to generate tumor nuclei-free antigen-recipient DC-like (tarDC-like) cells. When cultured as single cells on the device, these cells could survive under gentle medium perfusion with a median survival time of 11.5 h, although a few cells could survive longer than 36 h. Overall, this study demonstrates single-cell surgery in a microfluidic device for potential generation of dendritic cell vaccines which are uncontaminated with tumor nucleic materials. We believe that this study will inspire the generation of safer tumor cell vaccines for cancer immunotherapy.     

Development and validation of a fully GMP-compliant production process of autologous,tumor-lysate-pulsed dendritic cells

Background and aimsOne of the major challenges of dendritic cell (DC) vaccination is the establishment of harmonized DC production protocols. Here, we report the transfer and validation of a successfully used open DC manufacturing method into a closed system, good manufacturing practice (GMP)-compatible protocol.MethodsAll production steps (lysate generation, monocyte selection, DC culture and cryopreservation) were standardized and validated.ResultsTumor lysate was characterized by histology, mechanically homogenized and avitalized. This preparation yielded a median of 58 ± 21 μg protein per milligram of tumor tissue. Avitality was determined by trypan blue staining and confirmed in an adenosine triphosphate release assay. Patient monocytes were isolated by elutriation or CD14 selection, which yielded equivalent results. DCs were subsequently differentiated in Teflon bags for an optimum of 7 days in CellGro medium supplemented with interleukin (IL)-4 and granulocyte macrophage colony stimulating factor and then matured for 48 h in tumor necrosis factor-α and IL-1ß after pulsing with tumor lysate. This protocol resulted in robust and reproducible upregulation of DC maturation markers such as cluster of differentiation (CD)80, CD83, CD86, human leukocyte antigen-DR and DC-SIGN. Functionality of these DCs was shown by directed migration toward C-C motif chemokine ligand 19/21, positive T-cell stimulatory capacity and the ability to prime antigen-specific T cells from naive CD8⁺ T cells. Phenotype stability, vitality and functionality of DCs after cryopreservation, thawing and washing showed no significant loss of function. Comparison of clinical data from 146 patients having received vaccinations with plate-adherence versus GMP-grade DCs showed no inferiority of the latter.ConclusionsOur robust, validated and approved protocol for DC manufacturing forms the basis for a harmonized procedure to produce cancer vaccines, which paves the way for larger multi-center clinical trials.     

Adoptive cellular immunotherapy for the treatment of patients with breast cancer: A meta-analysis

BackgroundTo evaluate the therapeutic efficacy of dendritic cells (DC) alone, cytokine-induced killer (CIK) cells alone and the combination of DC and CIK cells in the treatment of breast cancer, we performed a systemic review of the relevant published clinical studies, collectively referred to as DC-CIK cell therapy.MethodsSix hundred thirty-three patients with breast cancer were assigned to cohorts, and a meta-analysis was conducted.ResultsThe treatment of breast cancer with DC-CIK cells was associated with a significantly improved 1-year survival (P = 0.0001). The Karnofsky performance status scale of the patients treated with DC-CIK cells was significantly improved compared with that of the non-DC-CIK group (P < 0.0001). The percentage of T cells (CD3⁺, CD4⁺ and CD4⁺CD8⁺), CD16⁺ monocytes, and CD3⁺CD56⁺ natural killer T cells in the peripheral blood of cancer patients was significantly increased (P ≤ 0.05), whereas the percentage of CD4⁺CD25⁺ regulatory T cells was not significantly decreased (P = 0.32) in the DC-CIK treatment group compared with the non-DC-CIK group. The levels of interleukin-2, interleukin-12, tumor necrosis factor-α, interferon-γ, and nucleolar organizer region protein in the peripheral blood of cancer patients, which reflect immune function, were significantly increased (P < 0.001) after DC-CIK cell treatment. Furthermore, after DC-CIK treatment, the average levels of the alpha-fetoprotein, cancer antigen embryonic antigen and carbohydrate antigen tumor markers were decreased (P < 0.00001).ConclusionsDC-CIK cell therapy markedly prolongs survival time, enhances immune function, and improves the efficacy of the treatment of breast cancer patients.     

Magnetic resonance and near-infrared imaging using a novel dual-modality nano-probe for dendritic cell tracking in vivo

Background aimsThe effect of cellular-based immunotherapy is highly correlated with the success of dendritic cells (DCs) homing to the draining lymph nodes (LNs) and interacting with antigen-specific CD4⁺ T cells. In this study, a novel magneto-fluorescent nano-probe was used to track the in vivo migration of DCs to the draining LNs.MethodsA dual-modality nano-probe composed of superparamagnetic iron oxide (SPIO) and near-infrared fluorescent (NIRF) dye (NIR797) was developed, and its magnetic and optical contrasting properties were characterized. DCs generated from mouse bone marrow were co-cultured with the probe at a lower concentration of 10 μg/mL. The cell phenotype and function of DCs were also investigated by fluorescence-activated cell sorting analysis and mixed leukocyte reactivity assay. Labeled DCs were injected into the footpad of C57BL/6 mice. Afterward, magnetic resonance imaging, NIRF imaging, Perls staining and CD11c immunofluorescence were used to observe the migration of the labeled DCs into draining LNs.ResultsThe synthetic SPIO-NIR797 nano-probe had a desirable superparamagnetic and near-infrared behavior. Perls staining showed perfect labeling efficiency. The cell phenotypes, including CD11c, CD80, CD86 and major histocompatibility complex class II, as well as the T-cell activation potential of the mature DCs were insignificantly affected after incubation (P > 0.05). Labeled DCs migrating into LNs could be detected by both magnetic resonance imaging and NIRF imaging simultaneously, which was further confirmed by Perls staining and immunofluorescence.ConclusionsThe novel dual-modality SPIO-NIR797 nano-probe has highly biocompatible characteristics for labeling and tracking DCs, which can be used to evaluate cancer immunotherapy in clinical applications.