Pre-clinical characterization of GMP grade CCL21-gene modified dendritic cells for application in a phase I trial in non-small cell lung cancer

Sustained Secretion of CCL21 via an Implantable Cell Reservoir Hydrogel Enhances the Systemic Antitumor Effect of Radiotherapy

The combination of radiotherapy (RT) and immunotherapy shows promise in improving the clinical treatment of solid tumors; however, it faces challenges of low response rates and systemic toxicity. Herein, an implantable alginate/collagen hydrogel encapsulating C-C motif ligand 21 (CCL21)-expressing dendritic cells (CCL21-DCs@gel) was developed to potentiate the systemic antitumor effects of RT. The hydrogel functioned as a suitable reservoir for in vivo culture and proliferation of CCL21-DCs, thereby enabling sustained CCL21 release. The local CCL21 gradient induced by CCL21-DCs@gel significantly enhanced the efficacy of RT in suppressing primary tumor growth and inhibiting distant metastasis across several mouse models. Furthermore, the combination of RT with CCL21-DCs@gel provided complete prophylactic protection to mice. Mechanistic investigations revealed that CCL21-DCs@gel potentiated RT by promoting tumor lymphangiogenesis and attracting immune cell infiltration into the tumor. Collectively, these results suggest that CCL21-DCs@gel is a promising adjunct to RT for effectively eradicating tumors and preventing tumor recurrence.

Engineering Challenges and Opportunities in Autologous Cellular Cancer Immunotherapy

The use of a patient's own immune or tumor cells, manipulated ex vivo, enables Ag- or patient-specific immunotherapy. Despite some clinical successes, there remain significant barriers to efficacy, broad patient population applicability, and safety. Immunotherapies that target specific tumor Ags, such as chimeric Ag receptor T cells and some dendritic cell vaccines, can mount robust immune responses against immunodominant Ags, but evolving tumor heterogeneity and antigenic downregulation can drive resistance. In contrast, whole tumor cell vaccines and tumor lysate-loaded dendritic cell vaccines target the patient's unique tumor antigenic repertoire without prior neoantigen selection; however, efficacy can be weak when lower-affinity clones dominate the T cell pool. Chimeric Ag receptor T cell and tumor-infiltrating lymphocyte therapies additionally face challenges related to genetic modification, T cell exhaustion, and immunotoxicity. In this review, we highlight some engineering approaches and opportunities to these challenges among four classes of autologous cell therapies.

Dendritic Cell Vaccination in Non-Small Cell Lung Cancer: Remodeling the Tumor Immune Microenvironment

Non-small-cell lung cancer (NSCLC) remains one of the leading causes of death worldwide. While NSCLCs possess antigens that can potentially elicit T cell responses, defective tumor antigen presentation and T cell activation hinder host anti-tumor immune responses. The NSCLC tumor microenvironment (TME) is composed of cellular and soluble mediators that can promote or combat tumor growth. The composition of the TME plays a critical role in promoting tumorigenesis and dictating anti-tumor immune responses to immunotherapy. Dendritic cells (DCs) are critical immune cells that activate anti-tumor T cell responses and sustain effector responses. DC vaccination is a promising cellular immunotherapy that has the potential to facilitate anti-tumor immune responses and transform the composition of the NSCLC TME via tumor antigen presentation and cell-cell communication. Here, we will review the features of the NSCLC TME with an emphasis on the immune cell phenotypes that directly interact with DCs. Additionally, we will summarize the major preclinical and clinical approaches for DC vaccine generation and examine how effective DC vaccination can transform the NSCLC TME toward a state of sustained anti-tumor immune signaling.

Chemokines and NSCLC: Emerging role in prognosis, heterogeneity, and therapeutics

Lung cancer persists to contribute to one-quarter of cancer-associated deaths. Among the different histologies, non-small cell lung cancer (NSCLC) alone accounts for 85% of the cases. The development of therapies involving immune checkpoint inhibitors and angiogenesis inhibitors has increased patients' survival probability and reduced mortality rates. Developing targeted therapies against essential genetic alterations also translates to better treatment strategies. But the benefits still seem farfetched due to the development of drug resistance and refractory tumors. In this review, we have highlighted the interplay of different tumor microenvironment components, essentially discussing the chemokine families (CC, CXC, C, and CX3C) that regulate the tumor biology in NSCLC and promote tumor growth, metastasis, and associated heterogeneity. The development of therapeutics and prognostic markers is a complex and multipronged approach. However, some essential chemokines can act as critical players for being considered potential prognostic markers and therapeutic targets.

Technical Feasibility and Safety of Repeated Computed Tomography-Guided Transthoracic Intratumoral Injection of Gene-Modified Cellular Immunotherapy in Metastatic NSCLC

Introduction

To assess the technical feasibility and safety of repeated percutaneous computed tomography (CT)–guided transthoracic biopsies and intratumoral injections of gene-modified dendritic cells in metastatic NSCLC.

Methods

A total of 15 patients with 15 NSCLC lesions measuring greater than 1.0 cm underwent two cycles of intratumoral biopsies and CCL21 dendritic cell injections separated by 7 days. All needle placements and injections were done under CT guidance. Clinical and imaging follow-up was done approximately 4 weeks after the first procedure. Safety and feasibility were determined as: (1) safety and feasibility similar to that of single-needle biopsy, and (2) an absence of serious adverse events defined as grade greater than or equal to three according to the National Cancer Institute Common Terminology Criteria for Adverse Events version 5.0.

Results

A total of 30 percutaneous, transthoracic intratumoral biopsies and injections into the lung cancer were performed, two cycles (at d 0 and 7) received by each patient (311 biopsies and 96 intratumoral injections). All percutaneous cases achieved technical success with respect to needle placement for both biopsy and injection of CCL21 dendritic cells. Only minor complications were observed (grade <3), including pneumothorax (n = 10, 33%) and small postbiopsy hemorrhage (n = 2, 7%). Pneumothorax was moderate (n = 1) or trace (n = 9), with resolution of the moderate pneumothorax after manual aspiration without chest tube placement. No patient required chest tube placement. No other complications or serious adverse effects related to the biopsy or dendritic cell injection were noted. All patients were in stable condition after up to 4 hours in the recovery unit and were discharged home on the same day. No procedure-related complications were observed on imaging or clinical follow-up at 4 weeks.

Conclusions

Repeated percutaneous, transthoracic CT-guided biopsies and intratumoral gene-modified cell-based immunotherapy injections into lung cancers are technically feasible, safe, and reproducible. There were no procedure-related serious (defined as grade ≥3) adverse events.

CCR7 as a therapeutic target in Cancer

The CCR7 chemokine axis is comprised of chemokine ligand 21 (CCL21) and chemokine ligand 19 (CCL19) acting on chemokine receptor 7 (CCR7). This axis plays two important but apparently opposing roles in cancer. On the one hand, this axis is significantly engaged in the trafficking of a number of effecter cells involved in mounting an immune response to a growing tumour. This suggests therapeutic strategies which involve potentiation of this axis can be used to combat the spread of cancer. On the other hand, the CCR7 axis plays a significant role in controlling the migration of tumour cells towards the lymphatic system and metastasis and can thus contribute to the expansion of cancer. This implies that therapeutic strategies which involve decreasing signaling through the CCR7 axis would have a beneficial effect in preventing dissemination of cancer. This dichotomy has partly been the reason why this axis has not yet been exploited, as other chemokine axes have, as a therapeutic target in cancer. Recent report of a crystal structure for CCR7 provides opportunities to exploit this axis in developing new cancer therapies. However, it remains unclear which of these two strategies, potentiation or antagonism of the CCR7 axis, is more appropriate for cancer therapy. This review brings together the evidence supporting both roles of the CCR7 axis in cancer and examines the future potential of each of the two different therapeutic approaches involving the CCR7 axis in cancer.

Nanoformulation of CCL21 greatly increases its effectiveness as an immunotherapy for neuroblastoma

Neuroblastoma is the most commonly diagnosed extracranial solid tumor in children. The patients with aggressive metastatic disease or refractory/relapsed neuroblastoma currently face a dismally low chance of survival. Thus, there is a great need for more effective therapies for this illness. In previous studies, we, as well as others, showed that the immune cell chemoattractant C-C motif chemokine ligand 21 (CCL21) is effective as an intratumoral therapy able to slow the growth of cancers. In this current study, we developed and tested an injectable, slow-release, uniform, and optimally loaded alginate nanoformulation of CCL21 as a means to provide prolonged intratumoral treatment. The alginate-nanoformulated CCL21, when injected intratumorally into mice bearing neuroblastoma lesions, significantly prolonged survival and decreased the tumor growth rate compared to CCL21 alone, empty nanoparticles, or buffer. Notably, we also observed complete tumor clearance and subsequent full protection against tumor rechallenge in 33% of nanoformulated CCL21-treated mice. Greater intratumoral presence of nanoformulated CCL21, compared to free CCL21, at days 1 and 2 after treatment ended was confirmed through fluorescent labeling and tracking. Nanoformulated CCL21-treated tumors exhibited a general pattern of prolonged increases in anti-tumor cytokines and relatively lower levels of pro-tumor cytokines in comparison to tumors treated with CCL21 alone or buffer only. Thus, this novel nanoformulation of CCL21 is an effective treatment for neuroblastoma, and may have potential for the delivery of CCL21 to other types of solid tumors in the future and as a slow-release delivery modality for other immunotherapies.

Intratumor injection of CCL21-coupled vault nanoparticles is associated with reduction in tumor volume in an in vivo model of glioma

PURPOSE

Glioblastoma (GBM) is the most common and malignant primary adult brain tumor. Current care includes surgical resection, radiation, and chemotherapy. Recent clinical trials for GBM have demonstrated extended survival using interventions such as tumor vaccines or tumor-treating fields. However, prognosis generally remains poor, with expected survival of 20 months after randomization. Chemokine-based immunotherapy utilizing CCL21 locally recruits lymphocytes and dendritic cells to enhance host antitumor response. Here, we report a preliminary study utilizing CPZ-vault nanoparticles as a vehicle to package, protect, and steadily deliver therapy to optimize CCL21 therapy in a murine flank model of GBM.

METHODS

GL261 cells were subcutaneously injected into the left flank of eight-week-old female C57BL/6 mice. Mice were treated with intratumoral injections of either: (1) CCL21-packaged vault nanoparticles (CPZ-CCL21), (2) free recombinant CCL21 chemokine empty vault nanoparticles, (3) empty vault nanoparticles, or 4) PBS.

RESULTS

The results of this study showed that CCL21-packaged vault nanoparticle injections can decrease the tumor volume in vivo. Additionally, this study showed mice injected with CCL21-packaged vault nanoparticle had the smallest average tumor volume and remained the only treatment group with a negative percent change in tumor volume.

CONCLUSIONS

This preliminary study establishes vault nanoparticles as a feasible vehicle to increase drug delivery and immune response in a flank murine model of GBM. Future animal studies involving an intracranial orthotopic tumor model are required to fully evaluate the potential for CCL21-packaged vault nanoparticles as a strategy to bypass the blood brain barrier, enhance intracranial immune activity, and improve intracranial tumor control and survival.

Electroporation as a method of choice to generate genetically modified dendritic cell cancer vaccines

In the last few decades, immunotherapy has emerged as an alternative therapeutic approach to treat cancer. Immunotherapy offers a plethora of different treatment possibilities. Among these, dendritic cell (DC)-based cancer vaccines constitute one of the most promising and valuable therapeutic options. DC-vaccines have been introduced into the clinics more than 15 years ago, and preclinical studies showed their general safety and low toxic effects on patients. However, their treatment efficacy is still rather limited, demanding for novel avenues to improve vaccine efficacy. One way to potentially achieve this is to focus on improving the DC-T cell interaction to further increase T cell priming and downstream activity. A successful DC-T cell interaction requires three different signals (Figure 1): (1) Major Histocompatibility Complex (MHC) and antigen complex interaction with T cell receptor (TCR) (2) interaction between co-stimulatory molecules and their cognate ligands at the cell surface and (3) secretion of cytokines to polarize the immune response toward a Type 1 helper (Th1) phenotype. In recent years, many studies attempted to improve the DC-T cell interaction and overall cancer vaccine therapeutic outcomes by increasing the expression of mediators of signal 1, 2 and/or 3, through genetic modifications of DCs. Transfection of genes of interest can be achieved through many different methods such as passive pulsing, lipofection, viral transfection, or electroporation (EP). However, EP is currently emerging as the method of choice thanks to its safety, versatility, and relatively easy clinical translation. In this review we will highlight the potential benefits of EP over other transfection methods as well as giving an overview of the available studies employing EP to gene-modify DCs in cancer vaccines. Crucial aspects such as safety, feasibility, and gene(s) of choice will be also discussed, together with future perspectives and opportunities for DC genetic engineering.

CCL21 Programs Immune Activity in Tumor Microenvironment

CCL21 promotes immune activity in the tumor microenvironment (TME) by colocalizing dendritic cells (DC) and T cells programing ectopic lymph node architectural structures that correlate with cancer prognosis. Innovative strategies to deliver CCL21 in cancer patients will reactivate the downregulated immune activity in the TME. Immune escape mechanisms are upregulated in the TME that promote tumor immune evasion. CCL21 combined with inhibition of dominant pathways of immune evasion will aid in the development of effective immunotherapy for cancer.

Strategies to Genetically Modulate Dendritic Cells to Potentiate Anti-Tumor Responses in Hematologic Malignancies

Dendritic cell (DC) vaccination has been investigated as a potential strategy to target hematologic malignancies, while generating sustained immunological responses to control potential future relapse. Nonetheless, few clinical trials have shown robust long-term efficacy. It has been suggested that a combination of surmountable shortcomings, such as selection of utilized DC subsets, DC loading and maturation strategies, as well as tumor-induced immunosuppression may be targeted to maximize anti-tumor responses of DC vaccines. Generation of DC from CD34+ hematopoietic stem and progenitor cells (HSPCs) may provide potential in patients undergoing allogeneic HSPC transplantations for hematologic malignancies. CD34+ HSPC from the graft can be genetically modified to optimize antigen presentation and to provide sufficient T cell stimulatory signals. We here describe beneficial (gene)-modifications that can be implemented in various processes in T cell activation by DC, among which major histocompatibility complex (MHC) class I and MHC class II presentation, DC maturation and migration, cross-presentation, co-stimulation, and immunosuppression to improve anti-tumor responses.

Low CCL-21 expression associates with unfavorable postoperative prognosis of patients with metastatic renal cell carcinoma

Background

Chemokine (C-C motif) ligand 21 (CCL21), a ligand of the chemokine (C-C motif) receptor 7, has recently been identified as an immuno-based anti-cancer molecule for its dendritic cells and T lymphocytes chemoattractant function. The aim of this study was to investigate prognostic values of CCL21 expression in metastatic renal cell carcinoma patients treated with targeted therapy.

Methods

This study included 111 patients with metastatic renal cell carcinoma receiving targeted therapy. CCL21 expression was analyzed by immunohistochemistry on tissue microarrays. Prognostic value of tumoral CCL21 expression and patients clinical outcomes were evaluated.

RESULTS

Kaplan-Meier method showed that low CCL21 expression was associated with shorter patient overall survival and progression-free survival (overall survival, P = 0.005; progression-free survival, P = 0.044). Further stratified analysis showed that low CCL21 expression was significantly associated with shorter overall survival in clear cell renal cell carcinoma patients (P = 0.017) and patients treated with sorafenib (P = 0.009). Low CCL21 expression was also an adverse independent risk factor for overall survival (hazard ratio, 2.106; 95% CI, 1.286-3.450; P = 0.003) and progression-free survival (hazard ratio 1.617; 95%CI 1.060-2.465; P = 0.026) in multivariate analyses. CCL21 expression was significantly associated with treatment best response to targeted therapy (P = 0.009). This molecule could also be combined with Heng risk model to increase its overall survival predictive accuracy.

Conclusion

Low CCL21 expression was a potential independent adverse prognostic biomarker for overall survival and progression-free survival for metastatic renal cell carcinoma patients treated with targeted therapy.

Cellular immunotherapy of cancer: an overview and future directions

The clinical success of checkpoint inhibitors has led to a renaissance of interest in cancer immunotherapies. In particular, the possibility of ex vivo expanding autologous lymphocytes that specifically recognize tumor cells has attracted much research and clinical trial interest. In this review, we discuss the historical background of tumor immunotherapy using cell-based approaches, and provide some rationale for overcoming current barriers to success of autologous immunotherapy. An overview of adoptive transfer of lymphocytes, tumor infiltrating lymphocytes and dendritic cell therapies is provided. We conclude with discussing the possibility of gene-manipulating immune cells in order to augment therapeutic activity, including silencing of the immune-suppressive zinc finger orphan nuclear receptor, NR2F6, as an attractive means of overcoming tumor-associated immune suppression.

Phase I Trial of Intratumoral Injection of CCL21 Gene-Modified Dendritic Cells in Lung Cancer Elicits Tumor-Specific Immune Responses and CD8+ T-cell Infiltration

Purpose: A phase I study was conducted to determine safety, clinical efficacy, and antitumor immune responses in patients with advanced non-small cell lung carcinoma (NSCLC) following intratumoral administration of autologous dendritic cells (DC) transduced with an adenoviral (Ad) vector expressing the CCL21 gene (Ad-CCL21-DC). We evaluated safety and tumor antigen-specific immune responses following in situ vaccination (ClinicalTrials.gov: NCT01574222).Experimental Design: Sixteen stage IIIB/IV NSCLC subjects received two vaccinations (1 × 10⁶, 5 × 10⁶, 1 × 10⁷, or 3 × 10⁷ DCs/injection) by CT- or bronchoscopic-guided intratumoral injections (days 0 and 7). Immune responses were assessed by tumor antigen-specific peripheral blood lymphocyte induction of IFNγ in ELISPOT assays. Tumor biopsies were evaluated for CD8⁺ T cells by IHC and for PD-L1 expression by IHC and real-time PCR (RT-PCR).Results: Twenty-five percent (4/16) of patients had stable disease at day 56. Median survival was 3.9 months. ELISPOT assays revealed 6 of 16 patients had systemic responses against tumor-associated antigens (TAA). Tumor CD8⁺ T-cell infiltration was induced in 54% of subjects (7/13; 3.4-fold average increase in the number of CD8⁺ T cells per mm²). Patients with increased CD8⁺ T cells following vaccination showed significantly increased PD-L1 mRNA expression.Conclusions: Intratumoral vaccination with Ad-CCL21-DC resulted in (i) induction of systemic tumor antigen-specific immune responses; (ii) enhanced tumor CD8⁺ T-cell infiltration; and (iii) increased tumor PD-L1 expression. Future studies will evaluate the role of combination therapies with PD-1/PD-L1 checkpoint inhibition combined with DC-CCL21 in situ vaccination. Clin Cancer Res; 23(16); 4556-68. ©2017 AACR.

Intranasal Antifungal Vaccination Using DNA-Transfected Dendritic Cells

Dendritic cells are the most potent antigen-presenting cells, and are critical for the generation of an antigen-specific immune response and protective immunity. These unique features have been applied to dendritic cell-based immunization in a number of disease conditions. Our published results have demonstrated that the immunity induced by intranasal immunization with DNA-transfected dendritic cells results in reduced fungal burden, and alleviated lung tissue damage in a mouse model of pulmonary fungal infection. In this article, approaches for the preparation and characterization of DNA-transfected dendritic cells and intranasal immunization in mice are described.

Loco-regional administration of nanomedicines for the treatment of lung cancer

Lung cancer poses one of the most significant challenges to modern medicine, killing thousands every year. Current therapy involves surgical resection supplemented with chemotherapy and radiotherapy due to high rates of relapse. Shortcomings of currently available chemotherapy protocols include unacceptably high levels of systemic toxicity and low accumulation of drug at the tumor site. Loco-regional delivery of nanocarriers loaded with anticancer agents has the potential to significantly increase efficacy, while minimizing systemic toxicity to anticancer agents. Local drug administration at the tumor site using nanoparticulate drug delivery systems can reduce systemic toxicities observed with intravenously administered anticancer drugs. In addition, this approach presents an opportunity for sustained delivery of anticancer drug over an extended period of time. Herein, the progress in the development of locally administered nanomedicines for the treatment of lung cancer is reviewed. Administration by inhalation, intratumoral injection and means of direct in situ application are discussed, the benefits and drawbacks of each modality are explored.

Role of Chemokines in Non-Small Cell Lung Cancer: Angiogenesis and Inflammation

Non-small cell lung cancer (NSCLC) is one of the most common types of aggressive cancer. The tumor tissue, which shows an active angiogenesis, is composed of neoplastic and stromal cells, and an abundant inflammatory infiltrate. Angiogenesis is important to support tumor growth, while infiltrating cells contribute to the tumor microenvironment through the secretion of growth factors, cytokines and chemokines, important molecules in the progression of the disease. Chemokines are important in development, activation of the immune response, and physiological angiogenesis. Chemokines have emerged as important regulators in the pathophysiology of cancer. These molecules are involved in the angiogenesis/angiostasis balance and in the recruitment of tumor infiltrating hematopoietic cells. In addition, chemokines promote tumor cell survival, as well as the directing and establishment of tumor cells to metastasis sites. The findings summarized here emphasize the central role of chemokines as modulators of tumor angiogenesis and their potential role as therapeutic targets in the inflammatory process of NSCLC angiogenesis.

Chemokine-Derived Peptides: Novel Antimicrobial and Antineoplasic Agents

Chemokines are a burgeoning family of chemotactic cytokines displaying a broad array of functions such as regulation of homeostatic leukocyte traffic and development, as well as activating the innate immune system. Their role in controlling early and late inflammatory stages is now well recognized. An improper balance either in chemokine synthesis or chemokine receptor expression contributes to various pathological disorders making chemokines and their receptors a useful therapeutic target. Research in this area is progressing rapidly, and development of novel agents based on chemokine/chemokine receptors antagonist functions are emerging as attractive alternative drugs. Some of these novel agents include generation of chemokine-derived peptides (CDP) with potential agonist and antagonist effects on inflammation, cancer and against bacterial infections. CDP have been generated mainly from N- and C-terminus chemokine sequences with subsequent modifications such as truncations or elongations. In this review, we present a glimpse of the different pharmacological actions reported for CDP and our current understanding regarding the potential use of CDP alone or as part of the novel therapies proposed in the treatment of microbial infections and cancer.

The role of CCL21/CCR7 chemokine axis in breast cancer-induced lymphangiogenesis

Background

Tumor-induced lymphangiogenesis facilitates breast cancer progression by generating new lymphatic vessels that serve as conduits for tumor dissemination to lymph nodes and beyond. Given the recent evidence suggesting the implication of C-C chemokine ligand 21/chemokine receptor 7 (CCL21/CCR7) in lymph node metastasis, the aim of our study was to define the role of this chemokine pair in breast cancer-associated lymphangiogenesis.

Methods

The expression analysis of CCL21/CCR7 pair and lymphatic endothelial cell (LEC) markers in breast cancer specimens was performed by means of quantitative real-time PCR. By utilizing CCR7 and CCL21 gene manipulated breast cancer cell implants into orthotopic sites of nude mice, lymphatic vessel formation was assessed through quantitative real-time PCR, immunohistochemistry and immunofluorescence assays. Finally, the lymphangiogenic potential of CCL21/CCR7 was assessed in vitro with primary LECs through separate functional assays, each attempting to mimic different stages of the lymphangiogenic process.

Results

We found that CCR7 mRNA expression in human breast cancer tissues positively correlates with the expression of lymphatic endothelial markers LYVE-1, podoplanin, Prox-1, and vascular endothelial growth factor-C (VEGF-C). We demonstrated that the expression of CCL21/CCR7 by breast cancer cells has the ability to promote tumor-induced lymph-vascular recruitment in vivo. In vitro, CCL21/CCR7 chemokine axis regulates the expression and secretion of lymphangiogenic factor VEGF-C and thereby promotes proliferation, migration, as well as tube formation of the primary human LECs. Finally, we showed that protein kinase B (AKT) signaling pathway is the intracellular mechanism of CCR7-mediated VEGF-C secretion by human breast cancer cells.

Conclusions

These results reveal that CCR7 and VEGF-C display a significant crosstalk and suggest a novel role of the CCL21/CCR7 chemokine axis in the promotion of breast cancer-induced lymphangiogenesis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-015-0306-4) contains supplementary material, which is available to authorized users.

Chemokines in cancer development and progression and their potential as targeting molecules for cancer treatment

Chemokines were initially identified as bioactive substances, which control the trafficking of inflammatory cells including granulocytes and monocytes/macrophages. Moreover, chemokines have profound impacts on other types of cells associated with inflammatory responses, such as endothelial cells and fibroblasts. These observations would implicate chemokines as master regulators in various inflammatory responses. Subsequent studies have further revealed that chemokines can regulate the movement of a wide variety of immune cells including lymphocytes, natural killer cells, and dendritic cells in both physiological and pathological conditions. These features endow chemokines with crucial roles in immune responses. Furthermore, increasing evidence points to the vital effects of several chemokines on the proliferative and invasive properties of cancer cells. It is widely acknowledged that cancer develops and progresses to invade and metastasize in continuous interaction with noncancerous cells present in cancer tissues, such as macrophages, lymphocytes, fibroblasts, and endothelial cells. The capacity of chemokines to regulate both cancerous and noncancerous cells highlights their crucial roles in cancer development and progression. Here, we will discuss the roles of chemokines in carcinogenesis and the possibility of chemokine targeting therapy for the treatment of cancer.

CCL21 Cancer Immunotherapy

Cancer, a major health problem, affects 12 million people worldwide every year. With surgery and chemo-radiation the long term survival rate for the majority of cancer patients is dismal. Thus novel treatments are urgently needed. Immunotherapy, the harnessing of the immune system to destroy cancer cells is an attractive option with potential for long term anti-tumor benefit. Cytokines are biological response modifiers that stimulate anti-tumor immune responses. In this review, we discuss the anti-tumor efficacy of the chemotactic cytokine CCL21 and its pre-clinical and clinical application in cancer.

Therapeutic use of dendritic cells to promote the extranodal priming of anti-tumor immunity

Ectopic lymphoid tissue, also known as tertiary lymphoid organs (TLO) develop adaptively within sites of chronic tissue inflammation, thereby allowing the host to efficiently crossprime specific immune effector cells within sites of disease. Recent evidence suggests that the presence of TLO in the tumor microenvironment (TME) predicts better overall survival. We will discuss the relevance of extranodal T cell priming within the TME as a means to effectively promote anti-tumor immunity and the strategic use of dendritic cell (DC)-based therapies to reinforce this clinically preferred process in the cancer-bearing host.

Development of the vault particle as a platform technology

Vaults are naturally occurring nanoparticles found widely in eukaryotes. The particles can be produced in large quantities and are assembled in situ from multiple copies of the single structural protein following expression. Using molecular engineering, recombinant vaults can be functionally modified and targeted, and their contents can be controlled by packaging. Here, we review the development of engineered vaults as a platform for a wide variety of therapeutic applications and we examine future directions for this unique nanoparticle system.

Chemokine-based immunotherapy: delivery systems and combination therapies

A major role of chemokines is to mediate leukocyte migration through interaction with G-protein-coupled receptors. Various delivery systems have been developed to utilize the chemokine properties for combating disease. Viral and mutant viral vectors expressing chemokines, genetically modified dendritic cells with chemokine or chemokine receptors, engineered chemokine-expressing tumor cells and pDNA encoding chemokines are among these methods. Another approach for inducing a targeted immune response is fusion of a targeting antibody or antibody fragment to a chemokine. In addition, chemokines induce more effective antitumor immunity when used as adjuvants. In this regard, chemokines are codelivered along with antigens or fused as a targeting unit with antigenic moieties. In this review, several chemokines with their role in inducing immune response against different diseases are discussed, with a major emphasis on cancer.

CCL21 Chemokine Therapy for Lung Cancer

Lung cancer remains a challenging health problem with more than 1.1 million deaths worldwide annually. With current therapy, the long term survival for the majority of lung cancer patients remains low, thus new therapeutic strategies are needed. One such strategy would be to develop immune therapy for lung cancer. Immune approaches remain attractive because although surgery, chemotherapy, and radiotherapy alone or in combination produce response rates in all histological types of lung cancer, relapse is frequent. Strategies that harness the immune system to react against tumors can be integrated with existing forms of therapy for optimal responses toward this devastating disease. Both antigen presenting cell (APC) and T cell activities are reduced in the lung tumor microenvironment. In this review we discuss our experience with efforts to restore host APC and T cell activities in the lung cancer microenvironment by intratumoral administration of dendritic cells (DC) expressing the CCR7 receptor ligand CCL21 (secondary lymphoid chemokine, SLC). Based on the results demonstrating that CCL21 is an effective anti cancer agent in the pre-clinical lung tumor model systems, a phase I clinical trial was initiated using intratumoral injection of CCL21 gene modified autologous DC in lung cancer. Results from the trial thus far indicate tolerability, immune enhancement and tumor shrinkage via this approach.

The pros and cons of chemokines in tumor immunology

Innate and adaptive immune cells can intervene during tumor progression at different stages including initiation, angiogenesis, local spreading and distant metastasis formation. The net effect can be favorable or detrimental to tumor development, depending on the composition and activation status of the immune infiltrate. Chemokines can determine the distribution of immune cells in the tumor microenvironment and also affect stroma composition. Here we consider how a complex network of chemokines plays a key role in dictating the fate of a tumor. Although the field is in its infancy, we also highlight how targeting chemokines offers a tool to modulate the tumor environment with the aim of enhancing immune-mediated rejection of cancer.

Chemokines, costimulatory molecules and fusion proteins for the immunotherapy of solid tumors

In this article, the role of chemokines and costimulatory molecules in the immunotherapy of experimental murine solid tumors and immunotherapy used in ongoing clinical trials are presented. Chemokine networks regulate physiologic cell migration that may be disrupted to inhibit antitumor immune responses or co-opted to promote tumor growth and metastasis in cancer. Recent studies highlight the potential use of chemokines in cancer immunotherapy to improve innate and adaptive cell interactions and to recruit immune effector cells into the tumor microenvironment. Another critical component of antitumor immune responses is antigen priming and activation of effector cells. Reciprocal expression and binding of costimulatory molecules and their ligands by antigen-presenting cells and naive lymphocytes ensures robust expansion, activity and survival of tumor-specific effector cells in vivo. Immunotherapy approaches using agonist antibodies or fusion proteins of immunomodulatory molecules significantly inhibit tumor growth and boost cell-mediated immunity. To localize immune stimulation to the tumor site, a series of fusion proteins consisting of a tumor-targeting monoclonal antibody directed against tumor necrosis and chemokines or costimulatory molecules were generated and tested in tumor-bearing mice. While several of these reagents were initially shown to have therapeutic value, combination therapies with methods to delete suppressor cells had the greatest effect on tumor growth. In conclusion, a key conclusion that has emerged from these studies is that successful immunotherapy will require both advanced methods of immunostimulation and the removal of immunosuppression in the host.

Lymphatics: at the interface of immunity, tolerance, and tumor metastasis

The lymphatic system has long been accepted as a passive escape route for metastasizing tumor cells. The classic view that lymphatics solely regulate fluid balance, lipid metabolism, and immune cell trafficking to the LN is now being challenged. Research in the field is entering a new phase with increasing evidence suggesting that lymphatics play an active role modulating inflammation, autoimmune disease, and the anti-tumor immune response. Evidence exists to suggest that the lymphatics and chemokines guide LN bi-functionally, driving immunity vs. tolerance according to demand. At sites of chronic inflammation, autoimmunity, and tumors, however, the same chemokines and aberrant lymphangiogenesis foster disease progression. These caveats point to the existence of a complex, finely balanced relationship between lymphatics and the immune system in health and disease. This review discusses emerging concepts in the fields of immunology, tumor biology, and lymphatic physiology, identifying critical, overlapping functions of lymphatics, the LN and lymphoid factors in tipping the balance of immunity vs. tolerance in favor of a growing tumor.

Cellular therapy to treat haematological and other malignancies: progress and pitfalls

The recent Food and Drug Administration (FDA) approval of a cellular therapy to treat castration resistant prostate cancer has reinforced the potential of cellular therapy to consolidate current pharmacological approaches to treating cancer. The emergence of the cell manufacturing facility to facilitate clinical translation of these new methodologies allows greater access to these novel therapies. Here we review different strategies currently being explored to treat haematological malignancies with a focus on adoptive allogeneic or autologous transfer of antigen specific T cells, NK cells or dendritic cells. These approaches all aim to generate immunological responses against overexpressed tissue antigens, mismatched minor histocompatability antigens or tumour associated antigens. Current successes and limitations of these different approaches will be discussed with an emphasis on challenges encountered in generating long term engraftment, antigen selection and implementation as well as therapeutic immune monitoring of clinical responses, with examples from recent clinical trials.

Chapter six--Adenovirus-based immunotherapy of cancer: promises to keep

Progress in vector design and an increased knowledge of mechanisms underlying tumor-induced immune suppression have led to a new and promising generation of Adenovirus (Ad)-based immunotherapies, which are discussed in this review. As vaccine vehicles Ad vectors (AdVs) have been clinically evaluated and proven safe, but a major limitation of the commonly used Ad5 serotype is neutralization by preexistent or rapidly induced immune responses. Genetic modifications in the Ad capsid can reduce intrinsic immunogenicity and facilitate escape from antibody-mediated neutralization. Further modification of the Ad hexon and fiber allows for liver and scavenger detargeting and selective targeting of, for example, dendritic cells. These next-generation Ad vaccines with enhanced efficacy are now becoming available for testing as tumor vaccines. In addition, AdVs encoding immune-modulating products may be used to convert the tumor microenvironment from immune-suppressive and proinvasive to proinflammatory, thus facilitating cell-mediated effector functions that can keep tumor growth and invasion in check. Oncolytic AdVs, that selectively replicate in tumor cells and induce an immunogenic form of cell death, can also be armed with immune-activating transgenes to amplify primed antitumor immune responses. These novel immunotherapy strategies, employing highly efficacious AdVs in optimized configurations, show great promise and warrant clinical exploration.

Gene therapy for lung neoplasms

Both advanced-stage lung cancer and malignant pleural mesothelioma are associated with a poor prognosis. Advances in treatment regimens for both diseases have had only a modest effect on their progressive course. Gene therapy for thoracic malignancies represents a novel therapeutic approach and has been evaluated in several clinical trials. Strategies have included induction of apoptosis, tumor suppressor gene replacement, suicide gene expression, cytokine-based therapy, various vaccination approaches, and adoptive transfer of modified immune cells. This review considers the clinical results, limitations, and future directions of gene therapy trials for thoracic malignancies.

Novel CCL21-vault nanocapsule intratumoral delivery inhibits lung cancer growth

Background

Based on our preclinical findings, we are assessing the efficacy of intratumoral injection of dendritic cells (DC) transduced with an adenoviral vector expressing the secondary lymphoid chemokine (CCL21) gene (Ad-CCL21-DC) in a phase I trial in advanced non-small cell lung cancer (NSCLC). While this approach shows immune enhancement, the preparation of autologous DC for CCL21 genetic modification is cumbersome, expensive and time consuming. We are evaluating a non-DC based approach which utilizes vault nanoparticles for intratumoral CCL21 delivery to mediate antitumor activity in lung cancer.

Principal Findings

Here we describe that vault nanocapsule platform for CCL21 delivery elicits antitumor activity with inhibition of lung cancer growth. Vault nanocapsule packaged CCL21 (CCL21-vaults) demonstrated functional activity in chemotactic and antigen presenting activity assays. Recombinant vaults impacted chemotactic migration of T cells and this effect was predominantly CCL21 dependent as CCL21 neutralization abrogated the CCL21 mediated enhancement in chemotaxis. Intratumoral administration of CCL21-vaults in mice bearing lung cancer enhanced leukocytic infiltrates (CXCR3⁺T, CCR7⁺T, IFNγ⁺T lymphocytes, DEC205⁺ DC), inhibited lung cancer tumor growth and reduced the frequencies of immune suppressive cells [myeloid derived suppressor cells (MDSC), T regulatory cells (Treg), IL-10 T cells]. CCL21-vaults induced systemic antitumor responses by augmenting splenic T cell lytic activity against parental tumor cells.

Significance

This study demonstrates that the vault nanocapsule can efficiently deliver CCL21 to sustain antitumor activity and inhibit lung cancer growth. The vault nanocapsule can serve as an “off the shelf” approach to deliver antitumor cytokines to treat a broad range of malignancies.

Genetically modified dendritic cells in cancer immunotherapy: a better tomorrow?

IMPORTANCE OF THE FIELD

Dendritic cells (DC) are powerful antigen-presenting cells that induce and maintain primary cytotoxic T lymphocyte (CTL) responses directed against tumor antigens. Consequently, there has been much interest in their application as antitumor vaccines.

AREAS COVERED IN THIS REVIEW

A large number of DC-based vaccine trials targeting a variety of cancers have been conducted; however, the rate of reported clinically significant responses remains low. Modification of DC to express tumor antigens or immunostimulatory molecules through the transfer of genes or mRNA transfection offers a logical alternative with potential advantages over peptide- or protein antigen-loaded DC. In this article, we review the current results and future prospects for genetically modified DC vaccines for the treatment of cancer.

WHAT THE READER WILL GAIN

Genetically-modified dendritic cell-based vaccines represent a powerful tool for cancer therapy. Numerous preclinical and clinical studies have demonstrated the potential of dendritic cell vaccines alone or in combination with other therapeutic modalities.

TAKE HOME MESSAGE

Genetically modified DC-based anti-cancer vaccination holds promise, perhaps being best employed in the adjuvant setting with minimal residual disease after primary therapy, or in combination with other antitumor or immune-enhancing therapies.

New approaches to the development of adenoviral dendritic cell vaccines in melanoma

Considerable research in the field of immunotherapy for melanoma has demonstrated that this tumor type can be responsive to therapeutic immune activation strategies. In early clinical trials, vaccine strategies using dendritic cells (DCs) and adenovirus (Ad) vectors (AdVs) were safe and immunogenic, and induced clinical responses in a minority of patients. Research from the past several years has yielded an improved mechanistic understanding of DC biology, AdV effects on DCs and the crosstalk that occurs between antigen-loaded DCs and specific lymphocyte subsets. This knowledge base is being combined with technological advances in cytokine delivery, AdV design and in vivo DC targeting. These developments are leading to novel AdV-transduced DC-based therapeutic modalities that may further advance melanoma immunotherapy. Interactions between AdVs and DCs, initial clinical trial results, and new developments in DC engineering and in AdV biology are reviewed.

Gene therapy for mesothelioma and lung cancer

Both malignant pleural mesothelioma and advanced stage lung cancer are associated with a poor prognosis. Unfortunately, current treatment regimens have had only a modest effect on their progressive course. Gene therapy for thoracic malignancies represents a novel therapeutic approach and has been evaluated in a number of clinical trials over the last two decades. Using viral vectors or anti-sense RNA, strategies have included induction of apoptosis, tumor suppressor gene replacement, suicide gene expression, cytokine-based therapy, various vaccination approaches, and adoptive transfer of modified immune cells. This review will consider the clinical results, limitations, and future directions of gene therapy trials for thoracic malignancies.

The role of chemokines in cancer immune surveillance by the adaptive immune system

Chemokines are key molecules involved in the migration and homeostasis of immune cells. However, also tumor cells use chemokine signals for different processes such as tumor progression and metastasis. It is thus unclear whether chemokines, through their immunostimulatory roles, contribute to the repression of tumor cells by tumor immunosurveillance or whether chemokines act primarily as growth factors and chemoattractants for primary and metastatizing tumors, respectively. Research of recent years, using gene knockout mice, recombinant chemokines, and agents able to block chemokine actions, has provided further insight into the diverse functions of chemokines. Here, we review the current knowledge on the complex actions of chemokines at the interface of the immune system and the tumor.