Therapeutic Anticancer Vaccines Research Articles

Advances in Cancer Nanovaccines: Harnessing Nanotechnology for Broadening Cancer Immune Response.

Many advances have been made recently in the field of cancer immunotherapy, particularly with the development of treatments such as immune checkpoint inhibitors and adoptive cellular immunotherapy. The efficacy of immunotherapy is limited, however, owing to high levels of tumor heterogeneity and the immunosuppressive environments of advanced malignant tumors. Therefore, therapeutic anticancer vaccines have gradually become powerful tools for inducing valid antitumor immune responses and regulating the immune microenvironment. Tumor vaccines loaded in nanocarriers have become an indispensable delivery platform for tumor treatment because of their enhanced stability, targeting capability, and high level of safety. Through a unique design, cancer nanovaccines activate innate immunity and tumor-specific immunity simultaneously. For example, the design of cancer vaccines can incorporate strategies such as enhancing the stability and targeting of tumor antigens, combining effective adjuvants, cytokines, and immune microenvironment regulators, and promoting the maturation and cross-presentation of antigen-presenting cells (APCs). In this review, we discuss the design and preparation of nanovaccines for remodeling tumor antigen immunogenicity and regulating the immunosuppressive microenvironment.

Clinical significance of anticancer vaccines (literature review)

During the past few decades, the advances in cancer immunotherapy have revived interest in the potential use of vaccines for the malignant tumor treatment. Tumor-associated antigens, which are abnormally expressed by tumor cells, are of decisive importance in the development of anticancer vaccines. Through the stimulation of immunological memory, therapeutic anticancer vaccines can result in long-term remission or healing patients. Therapeutic anticancer vaccines due to the potential safety, specificity and duration of effect can become an alternative to or increase the effectiveness of existing immunotherapies. This article presents data on the tumor antigen structure, characteristics of anticancer vaccines and the results of studies on the clinical efficacy of anticancer vaccines.

Adjuvant oncolytic virotherapy for personalized anti-cancer vaccination

By conferring systemic protection and durable benefits, cancer immunotherapies are emerging as long-term solutions for cancer treatment. One such approach that is currently undergoing clinical testing is a therapeutic anti-cancer vaccine that uses two different viruses expressing the same tumor antigen to prime and boost anti-tumor immunity. By providing the additional advantage of directly killing cancer cells, oncolytic viruses (OVs) constitute ideal platforms for such treatment strategy. However, given that the targeted tumor antigen is encoded into the viral genomes, its production requires robust infection and therefore, the vaccination efficiency partially depends on the unpredictable and highly variable intrinsic sensitivity of each tumor to OV infection. In this study, we demonstrate that anti-cancer vaccination using OVs (Adenovirus (Ad), Maraba virus (MRB), Vesicular stomatitis virus (VSV) and Vaccinia virus (VV)) co-administered with antigenic peptides is as efficient as antigen-engineered OVs and does not depend on viral replication. Our strategy is particularly attractive for personalized anti-cancer vaccines targeting patient-specific mutations. We suggest that the use of OVs as adjuvant platforms for therapeutic anti-cancer vaccination warrants testing for cancer treatment.

Network- and systems-based re-engineering of dendritic cells with non-coding RNAs for cancer immunotherapy

Dendritic cells (DCs) are professional antigen-presenting cells that induce and regulate adaptive immunity by presenting antigens to T cells. Due to their coordinative role in adaptive immune responses, DCs have been used as cell-based therapeutic vaccination against cancer. The capacity of DCs to induce a therapeutic immune response can be enhanced by re-wiring of cellular signalling pathways with microRNAs (miRNAs).Methods: Since the activation and maturation of DCs is controlled by an interconnected signalling network, we deploy an approach that combines RNA sequencing data and systems biology methods to delineate miRNA-based strategies that enhance DC-elicited immune responses.Results: Through RNA sequencing of IKKβ-matured DCs that are currently being tested in a clinical trial on therapeutic anti-cancer vaccination, we identified 44 differentially expressed miRNAs. According to a network analysis, most of these miRNAs regulate targets that are linked to immune pathways, such as cytokine and interleukin signalling. We employed a network topology-oriented scoring model to rank the miRNAs, analysed their impact on immunogenic potency of DCs, and identified dozens of promising miRNA candidates, with miR-15a and miR-16 as the top ones. The results of our analysis are presented in a database that constitutes a tool to identify DC-relevant miRNA-gene interactions with therapeutic potential (https://www.synmirapy.net/dc-optimization).Conclusions: Our approach enables the systematic analysis and identification of functional miRNA-gene interactions that can be experimentally tested for improving DC immunogenic potency.

New Data on the Influence of the HPV16 E2 Early Protein Obtained in Plant Expression Nanosystems on Tumor Tissues of Female Mice Induced by Injection of HeLa Cancer Cells in Hip Muscle

The prospects of creating a therapeutic anti-cancer vaccine using the HPV16 E2 regulatory gene have been investigated. An expression system for the synthesis of early antigenic proteins HPV16 E2, of high-risk papillomavirus based on transgenic tomato fruits has been developed. To induce malignant transformation of tissues, female mice at an age of 6 months were injected with a suspension of HeLa cancer cells into the hip muscle. In 1 month, blood was collected from half of the mice, splenocytes were isolated from the spleen, and alterations in internal organs, including the lungs, were studied. The other half of the HeLa-injected mice received a peroral inoculation with vaccine material from tomatoes with HPV16 E2 (500 mg of E2 protein per mouse). In 1 month, blood was collected from the vaccinated mice, splenocytes were isolated, and alterations in internal organs were investigated. After the injection of HeLa tumor cells, the lungs increased in size and contained various tumors. The mice with HeLa administration and the peroral HPV16 E2 vaccination had no specific abnormalities in the size and morphology of the lungs. Comparing the levels of interferon, CD4 and CD8 T lymphocytes, as well as the cells that interacted with anti-granzyme B and anti-perforin antibodies, showed that HPV16 E2 vaccination increased the number of cells that bind antibodies to interferon, CD4 and CD8 T lymphocytes, granzyme B, and perforin by 1.5–2 orders of magnitude. The HPV16 E2 protein can significantly suppress the proliferation of cancer cells and can be used for the creation of a therapeutic vaccine against a cancer caused by the most highly oncogenic type of papillomavirus, HPV16.

Curatopes Melanoma: A Database of Predicted T-cell Epitopes from Overly Expressed Proteins in Metastatic Cutaneous Melanoma.

Therapeutic anticancer vaccination has been adapted as an immunotherapy in several solid tumors. However, the selection of promising candidates from the total quantity of possible epitopes poses a challenge to clinicians and bioinformaticians alike, and very few epitopes have been tested in experimental or clinical settings to validate their efficacy. Here, we present a comprehensive database of predicted nonmutated peptide epitopes derived from genes that are overly expressed in a group of 32 melanoma biopsies compared with healthy tissues and that were filtered against expression in a curated list of survival-critical tissues. We hypothesize that these "self-tolerant" epitopes have two desirable properties: they do not depend on mutations, being immediately applicable to a large patient collective, and they potentially cause fewer autoimmune reactions. To support epitope selection, we provide an aggregated score of expected therapeutic efficiency as a shortlist mechanism. The database has applications in facilitating epitope selection and trial design and is freely accessible at https://www.curatopes.com. SIGNIFICANCE: A database is presented that predicts and scores antitumor T-cell epitopes, with a focus on tolerability and avoidance of severe autoimmunity, offering a supplementary epitope set for further investigation in immunotherapy.

Preclinical evaluation of mRNA trimannosylated lipopolyplexes as therapeutic cancer vaccines targeting dendritic cells

Clinical trials with direct administration of synthetic mRNAs encoding tumor antigens demonstrated safety and induction of tumor-specific immune responses. Their proper delivery to dendritic cells (DCs) requires their protection against RNase degradation and more specificity for dose reduction. Lipid-Polymer-RNA lipopolyplexes (LPR) are attractive mRNA delivery systems and their equipment with mannose containing glycolipid, specific of endocytic receptors present on the membrane of DCs is a valuable strategy. In this present work, we evaluated the capacity of LPR functionalized with a tri-antenna of α-d-mannopyranoside (triMN-LPR) concerning (i) their binding to CD209/DC-SIGN and CD207/Langerin expressing cell lines, human and mouse DCs and other hematopoietic cell populations, (ii) the nature of induced immune response after in vivo immunization and (iii) their therapeutic anti-cancer vaccine efficiency. We demonstrated that triMN-LPR provided high induction of a local inflammatory response two days after intradermal injection to C57BL/6 mice, followed by the recruitment and activation of DCs in the corresponding draining lymph nodes. This was associated with skin production of CCR7 and CXCR4 at vaccination sites driving DC migration. High number of E7-specific T cells was detected after E7-encoded mRNA triMN-LPR vaccination. When evaluated in three therapeutic pre-clinical murine tumor models such as E7-expressing TC1 cells, OVA-expressing EG7 cells and MART-1-expressing B16F0 cells, triMN-LPR carrying mRNA encoding the respective antigens significantly exert curative responses in mice vaccinated seven days after initial tumor inoculation. These results provide evidence that triMN-LPR give rise to an efficient stimulatory immune response allowing for therapeutic anti-cancer vaccination in mice. This mRNA formulation should be considered for anti-cancer vaccination in Humans.

Necroptotic cancer cells-mimicry nanovaccine boosts anti-tumor immunity with tailored immune-stimulatory modality

Recent breakthroughs in cancer immunotherapy offer new paradigm-shifting therapeutic options for combating cancer. Personalized therapeutic anti-cancer vaccines training T cells to directly fight against tumor cells endogenously offer tremendous benefits in working synergistically with immune checkpoint inhibitors. Biomimetic nanotechnology offers a versatile platform to boost anticancer immunity by efficiently co-delivering optimized immunogenic antigen materials and adjuvants to antigen presenting cells (APC). Necroptotic tumor cells can release danger associated molecule patterns (DAMPs) like heat shock proteins, being more immunogenic than naïve tumor cells. Here, nano-size “artificial necroptotic cancer cell” (αHSP70p-CM-CaP) composing of phospholipid bilayer and a phosphate calcium core was designed as a flexible vaccine platform for co-delivering cancer membrane proteins (CM), DAMPs signal-augmenting element α-helix HSP70 functional peptide (αHSP70p) and CpG to both natural killer (NK) cells and APC. Mechanically, immunogenic B16OVA tumor cells membrane-associated antigens and αHSP70p were reconstituted in artificial outer phospholipid bilayer membrane via one-step hydration and CpG encapsulated in the phosphate calcium core. The resulted αHSP70p-CM-CaP exhibited 30 nm in diameter with the immunogenic membrane proteins reserved in the particles to produce synergistic effect on bone marrow derived dendritic cells maturation and antigen-presentation. Following αHSP70p-CM-CaP vaccination, efficient lymph node trafficking and multi-epitope-T cells response was observed in mice. Vitally, αHSP70p-CM-CaP was also able to induce expansion of IFN-γ-expressing CD8+ T cells and NKG2D+ NK cells subsets. Most promisingly, αHSP70p-CM-CaP vaccination led to the killing of target cells and tumor regression in vivo when combined with anti-PD-1 antibody treatment on mice B16OVA melanoma models. Altogether, we demonstrated proof-of-concept evidence for the feasibility, capability and safety of a nanovaccine platform towards efficient personalized anticancer application.

Stimulatory role of exosomes in the context of therapeutic anti-cancer vaccines.

Exosomes, the smallest of extracellular vesicles (EVs) produced by all cells and circulating freely in all body fluids, have been of interest as communication vehicles between cells (1). Much attention has been given to exosome origin and biogenesis as well as to the molecular/genetic cargo exosomes carry and deliver to recipient cells. Exosomes originate in the endosomal compartment of a parent cell.

Exploiting in situ antigen generation and immune modulation to enhance chemotherapy response in advanced melanoma: A combination nanomedicine approach

Therapeutic anticancer vaccine development must address a number of barriers to achieve successful tumor specific killing, including effective antigen presentation and antigen-specific T-cell activation to mediate cytotoxic cellular effects, inhibition of an immune-suppressive tumor microenvironment in order to facilitate and enhance CTL activity, and induction of memory T-cells to prolong tumor rejection. While traditional as well as modern vaccines rely upon delivery of both antigen and adjuvant, a variety of clinically relevant cancers lack ideal immunogenic antigens. Building upon recent efforts, we instead chose to exploit chemotherapy-induced apoptosis to allow for in situ antigen generation in a combination, nanomedicine-based approach. Specifically, lipid-coated cisplatin nanoparticles (LPC) and CpG-encapsulated liposomes (CpG-Lipo) were prepared for the temporally-controlled and multifaceted treatment of an advanced in vivo model of melanoma. Such combination therapy established strong synergistic effects, both in apoptotic extent and subsequent abrogation of tumor growth, which were due largely to both an enhanced cytotoxic T-cell recruitment and a reduction of immune-suppressive mediators in the microenvironments of both spleens and tumor. These results underlie a prolonged host lifespan in the combination approach (45 days) as compared with control (25 days, p < 0.02), providing promise toward a personalized approach to nanomedicine by establishing effect synergy in host-specific immunotherapy following chemotherapy.

Model-based genotype-phenotype mapping used to investigate gene signatures of immune sensitivity and resistance in melanoma micrometastasis.

In this paper, we combine kinetic modelling and patient gene expression data analysis to elucidate biological mechanisms by which melanoma becomes resistant to the immune system and to immunotherapy. To this end, we systematically perturbed the parameters in a kinetic model and performed a mathematical analysis of their impact, thereby obtaining signatures associated with the emergence of phenotypes of melanoma immune sensitivity and resistance. Our phenotypic signatures were compared with published clinical data on pretreatment tumor gene expression in patients subjected to immunotherapy against metastatic melanoma. To this end, the differentially expressed genes were annotated with standard gene ontology terms and aggregated into metagenes. Our method sheds light on putative mechanisms by which melanoma may develop immunoresistance. Precisely, our results and the clinical data point to the existence of a signature of intermediate expression levels for genes related to antigen presentation that constitutes an intriguing resistance mechanism, whereby micrometastases are able to minimize the combined anti-tumor activity of complementary responses mediated by cytotoxic T cells and natural killer cells, respectively. Finally, we computationally explored the efficacy of cytokines used as low-dose co-adjuvants for the therapeutic anticancer vaccine to overcome tumor immunoresistance.

Immune Monitoring Using mRNA-Transfected Dendritic Cells.

Dendritic cells are known to be the most potent antigen presenting cell in the immune system and are used as cellular adjuvants in therapeutic anticancer vaccines using various tumor-associated antigens or their derivatives. One way of loading antigen into the dendritic cells is by mRNA electroporation, ensuring presentation of antigen through major histocompatibility complex I and potentially activating T cells, enabling them to kill the tumor cells. Despite extensive research in the field, only one dendritic cell-based vaccine has been approved. There is therefore a great need to elucidate and understand the immunological impact of dendritic cell vaccination in order to improve clinical benefit. In this chapter, we describe a method for performing immune monitoring using peripheral blood mononuclear cells and autologous dendritic cells transfected with tumor-associated antigen-encoding mRNA.

Cancer vaccines: can they improve survival?

In patients with metastatic cancer, therapeutic anticancer vaccines are rarely associated with objective antitumor responses; so, many investigators have focused on progression-free survival (PFS) as a key endpoint for clinical trials. However, it is not clear that PFS is a surrogate for overall survival (OS), and OS may be a more appropriate endpoint because of the effects on long-term memory in the adaptive immune system. Recently, reported vaccine trials were reviewed to determine their primary and secondary endpoints and results. Randomized trials testing sipuleucel-T and prostvac-vf in prostate cancer and ipilimumab and eltrapuldencel-T in melanoma were associated with low objective response rates, no improvement in PFS, but statistically significant improvement in OS. Although compared with PFS, it takes longer to get a final result when OS is the primary endpoint; there is increasing evidence that if long-term memory recognition of tumor-associated antigens is the mechanism of action of an investigational product, then OS may be the only valid clinical endpoint for efficacy.

NKT cell-targeted vaccination plus anti-4–1BB antibody generates persistent CD8 T cell immunity against B cell lymphoma

Harnessing the immune adjuvant properties of natural killer T (NKT) cells is an effective strategy to generate anticancer immunity. The objective of this study was to increase the potency and durability of vaccine-induced immunity against B cell lymphoma by combining α-galactosylceramide (α-GalCer)-loaded tumor cell vaccination with an agonistic antibody targeting the immune checkpoint molecule 4–1BB (CD137). We observed potent synergy when combining vaccination and anti-4–1BB antibody treatment resulting in significantly enhanced survival of mice harboring Eμ-myc tumors, including complete eradication of lymphoma in over 50% of mice. Tumor-free survival required interferon γ (IFNγ)-dependent expansion of CD8+ T cells and was associated with 4–1BB-mediated differentiation of KLRG1+ effector CD8+ T cells. 'Cured' mice were also resistant to lymphoma re-challenge 80 days later indicating successful generation of immunological memory. Overall, our results demonstrate that therapeutic anticancer vaccination against B cell lymphoma using an NKT cell ligand can be boosted by subsequent co-stimulation through 4–1BB leading to a sustainable immune response that may enhance outcomes to conventional treatment.

Phase I trial of active specific immunotherapy with autologous dendritic cells pulsed with autologous irradiated tumor stem cells in hepatitis B positive patients with hepatocellular carcinoma

Background Active or chronic infections may be barriers to successful vaccines, and patients with hepatitis typically are excluded from clinical trials testing therapeutic anticancer vaccines. One concern is vaccines may exacerbate the underlying infection. Hepatocellular carcinoma (HCC) often arises in the context of viral hepatitis B (HBV) or hepatitis C (HBC), with or without cirrhosis. HCC is seldom cured by standard therapy because of undetectable micrometastatic disease that is present at diagnosis. Effective nontoxic adjunctive treatments might improve outcomes for HCC patients who are at high risk for recurrence and death despite surgical resection of their primary hepatoma. Active specific immunotherapy (ASI) with autologous dendritic cells loaded with antigens from autologous tumor stem cell lines has been associated with promising long-term survival in metastatic melanoma, but patients with HBV or HCV were ineligible. Therefore a Phase I safety trial in HCC patients with HBV and/or HIV was warranted. Patients and methods Patients with previously untreated HCC who were candidates for surgical resection, but not curable by resection or liver transplant were enrolled in Shanghai, China. Patients had a solitary lesion >5 cm in diameter, or 3 lesions with at least one > 3 cm, but no regional or distant metastatic disease. Patients had a good performance status, adequate blood counts and organ function. An autologous tumor cell (TC) line was established from the resected tumor. Irradiated autologous TC were incubated with autologous dendritic cells (DC) to create a patient-specific DC-TC product which was cryopreserved. Approximately eight weeks after one course of transarterial chemoembolization therapy (TACE), patients received three weekly subcutaneous injections of DC-TC suspended in 500 micrograms of sargramostim. Patients were monitored for toxicity for 8 weeks from the start of treatment.

Induction of cytotoxic T cells as a novel independent survival factor in malignant melanoma with percutaneous peptide immunization

BackgroundMalignant melanoma (MM) often shows multiple chemo-resistance, leading to poor prognosis of the patients. Therapeutic anti-cancer vaccination may be a feasible way to prolong the survival of patients. We have demonstrated that application of antigenic peptides via the tape-stripped, horny layer-removed skin, known as percutaneous peptide immunization (PPI), induces tumor cell-specific cytotoxic T lymphocytes (CTLs) in rodents and humans. ObjectiveTo evaluate clinical significance of PPI in advanced MM patients. MethodsWe performed PPI in 59 patients undergoing advanced MM with Melan-A, tyrosinase, MAGE-2, MAGE-3 and gp-100 peptides based on HLA typing in individuals. The induction of CTLs was assessed by the tetramer or pentamer flow cytometry in 35 patients. Patients showing positive CTL responses to all antigens were defined as complete responder (n=18), and those showing negative responses to at least one applied antigen were classified as incomplete responder (n=17). The primary endpoint of the study was overall survival (OS). For statistical analysis, log-rank test, univariate and multivariate Cox proportional hazard model were used. ResultsOS of the complete responders was longer than that of the incomplete responders (median survival time: 55.8 vs 20.3 months, log rank P=0.089). A hazard ratio for the complete responders relative to the incomplete responders was 0.23 (95% confidence interval: 0.06–0.93, P=0.039) in a multivariate Cox proportional hazard model. ConclusionThe induction of CTLs was a novel independent survival factor, and the induction of peptide-specific CTLs by PPI contributes to the prolonged survival and represents an impact on therapeutic approaches in MM.Unique trial number: UMIN000005706.

Chemokines as Cancer Vaccine Adjuvants.

We are witnessing a new era of immune-mediated cancer therapies and vaccine development. As the field of cancer vaccines advances into clinical trials, overcoming low immunogenicity is a limiting step in achieving full success of this therapeutic approach. Recent discoveries in the many biological roles of chemokines in tumor immunology allow their exploitation in enhancing recruitment of antigen presenting cells (APCs) and effector cells to appropriate anatomical sites. This knowledge, combined with advances in gene therapy and virology, allows researchers to employ chemokines as potential vaccine adjuvants. This review will focus on recent murine and human studies that use chemokines as therapeutic anti-cancer vaccine adjuvants.

Inhibition of tumor growth in vivo by a nanoparticle-based therapeutic cancer vaccine targeting HAAH

Meeting abstracts We have designed, developed and produced a lambda-phage based therapeutic anti-cancer vaccine (nanoparticle) targeting human aspartyl (asparaginyl) β-hydroxylase (HAAH). This protein is over-expressed on the surface of cancer cells and plays a central role in cancer etiology that

NKT cell adjuvant-based tumor vaccine for treatment of myc oncogene-driven mouse B-cell lymphoma

AbstractImmunomodulators are effective in controlling hematologic malignancy by initiating or reactivating host antitumor immunity to otherwise poorly immunogenic and immune suppressive cancers. We aimed to boost antitumor immunity in B-cell lymphoma by developing a tumor cell vaccine incorporating α-galactosylceramide (α-GalCer) that targets the immune adjuvant properties of NKT cells. In the Eμ-myc transgenic mouse model, single therapeutic vaccination of irradiated, α-GalCer–loaded autologous tumor cells was sufficient to significantly inhibit growth of established tumors and prolong survival. Vaccine-induced antilymphoma immunity required NKT cells, NK cells, and CD8 T cells, and early IL-12–dependent production of IFN-γ. CD4 T cells, gamma/delta T cells, and IL-18 were not critical. Vaccine treatment induced a large systemic spike of IFN-γ and transient peripheral expansion of both NKT cells and NK cells, the major sources of IFN-γ. Furthermore, this vaccine approach was assessed in several other hematopoietic tumor models and was also therapeutically effective against AML-ETO9a acute myeloid leukemia. Replacing α-GalCer with β-mannosylceramide resulted in prolonged protection against Eμ-myc lymphoma. Overall, our results demonstrate a potent immune adjuvant effect of NKT cell ligands in therapeutic anticancer vaccination against oncogene-driven lymphomas, and this work supports clinical investigation of NKT cell–based immunotherapy in patients with hematologic malignancies.

Maintenance and Consolidation Therapy in Patients with Unresectable Stage III/IV Non-Small Cell Lung Cancer

Globally, lung cancer is the leading cause of cancer-related mortality. Current chemotherapy combinations for the first-line treatment of advanced disease (stage IIIB with malignant pleural effusion/stage IV) and chemoradiotherapy regimens for the treatment of unresectable locally advanced disease (stage IIIA and IIIB without malignant pleural effusion) appear to have reached an efficacy plateau. The addition of new compounds including targeted agents to standard first-line cytotoxic doublets, administered concurrently and/or as maintenance therapy in patients who have not experienced disease progression after such treatment, has been shown to improve efficacy beyond this plateau in patients with advanced disease. However, to date, such approaches have been less successful in the treatment of patients with unresectable locally advanced stage III disease. The purpose of this review is to summarize the data from recent randomized phase III studies involving agents administered as maintenance or consolidation therapy in the treatment of unresectable stage III/IV non-small cell lung cancer (NSCLC). A possible alternative approach to the use of cytotoxic or molecularly targeted agents in this setting is the administration of therapeutic anticancer vaccines, which are designed to stimulate a host immunological response against the tumor. Current data in relation to the potential of vaccine therapy for NSCLC are therefore also reviewed, with a particular focus on belagenpumatucel-L and L-BLP25 vaccines, which are currently undergoing phase III evaluation as maintenance therapies in patients with unresectable stage III/IV NSCLC who have tumor control following first-line therapy.