Heat-shock protein vaccines as active immunotherapy against human gliomas

Immunoediting Dynamics in Glioblastoma: Implications for Immunotherapy Approaches

Glioblastoma is an aggressive primary brain tumor that poses many therapeutic difficulties because of the high rate of proliferation, genetic variability, and its immunosuppressive microenvironment. The theory of cancer immunoediting, which includes the phases of elimination, equilibrium, and escape, offers a paradigm for comprehending interactions between the immune system and glioblastoma. Immunoediting indicates the process by which immune cells initially suppress tumor development, but thereafter select for immune-resistant versions leading to tumor escape and progression. The tumor microenvironment (TME) in glioblastoma is particularly immunosuppressive, with regulatory T cells and myeloid-derived suppressor cells being involved in immune escape. To achieve an efficient immunotherapy for glioblastoma, it is crucial to understand these mechanisms within the TME. Existing immunotherapeutic modalities such as chimeric antigen receptor T cells and immune checkpoint inhibitors have been met with some level of resistance because of the heterogeneous nature of the immune response to glioblastoma. Solving these issues is critical to develop novel strategies capable of modulating the TME and re-establishing normal immune monitoring. Further studies should be conducted to identify the molecular and cellular events that underlie the immunosuppressive tumor microenvironment in glioblastoma. Comprehending and modifying the stages of immunoediting in glioblastoma could facilitate the development of more potent and long-lasting therapies.

Immuno-informatics analysis and expression of a novel multi-domain antigen as a vaccine candidate against glioblastoma

Glioblastoma multiform is the most common of primary malignant brain tumors in adults. Currently, surgical resection of the tumor mass, followed by adjuvant radiotherapy and chemotherapy are standard treatments for glioblastoma multiform but so far are not effective treatments. Thus, the development of a vaccine, as a safe and efficient strategy for prophylactic or therapeutic purposes against glioblastoma multiform is very necessary. The present study aimed to design the multi-domain vaccine for glioblastoma multiform. An in silico approach was used to select the most potent domains of proteins to induce the host's B- and T-cell immune response against glioblastoma multiform. IL-13Rα-2 (amino acid positions 27-144), TNC (amino acid positions 1900-2100), and PTPRZ-1(amino acid positions 731-884) were found to have potent inducible immune responses. So, we considered them for fusing with a linker A(EAAAK)₃A to construct the multi-domain recombinant vaccine. The immuno-informatics analysis of the designed recombinant vaccine construct was performed to evaluate its efficacy. Although the designed recombinant vaccine construct did not show allergen property, its antigenicity was estimated at 0.78. The Physico-chemical properties of the recombinant vaccine construct were characterized and revealed the potency of the vaccine candidate. Then its secondary and tertiary structures, mRNA structure, molecular docking, and immune simulation were predicted using bioinformatics tools. Next, the designed recombinant vaccine construct was synthesized, and cloned into the pET28a vector and expressed in E. coli BL21. Besides, the circular dichroism spectroscopy was utilized for the investigation of the secondary structure changes of the recombinant vaccine construct. The results of the verification assessment of the recombinant vaccine construct expression indicated that in silico analysis was relatively accurate, and relatively change occurred on the protein secondary structure. In our future plan, the vaccine candidate that was confirmed by in silico tools should be validated by further in vitro and in vivo experimental studies.

Genetically engineered mesenchymal stem cells: targeted delivery of immunomodulatory agents for tumor eradication

Cancer immunotherapy emerged as a novel therapeutic option that employs enhanced or amended native immune system to create a robust response against malignant cells. The systemic therapies with immune-stimulating cytokines have resulted in substantial dose-limiting toxicities. Targeted cytokine immunotherapy is being explored to overcome the heterogeneity of malignant cells and tumor cell defense with a remarkable reduction of systemic side effects. Cell-based strategies, such as dendritic cells (DCs), fibroblasts or mesenchymal stem cells (MSCs) seek to minimize the numerous toxic side effects of systemic administration of cytokines for extended periods of time. The usual toxicities comprised of a vascular leak, hypotension, and respiratory insufficiency. Natural and strong tropism of MSCs toward malignant cells made them an ideal systemic delivery vehicle to direct the proposed therapeutic genes to the vicinity of a tumor where their expression could evoke an immune reaction against the tumor. Compared with other methods, the delivery of cytokines via engineered MSCs is safer and renders a more practical, and promising strategy. Large numbers of genes code for cytokines have been utilized to reengineer MSCs as therapeutic cells. This review highlights the recent findings on the cytokine gene therapy for human malignancies by focusing on MSCs application in cancer immunotherapy.

In Vitro Generation of Anti-Osteosarcoma Cytotoxic Activity Using Dendritic Cells Loaded with Heat Shock Protein 70-Peptide Complexes

Introduction: This study aimed at evaluating the anti-osteosarcoma activity of cytotoxic T lymphocytes (CTLs) induced by dendritic cells (DCs) pulsed with heat shock protein 70-peptide complexes (Hsp70-PCs). Materials and methods: Human recombinant Hsp70 expression was analyzed using thin layer scanning and Western blot assay. Tumor antigens from Saos-2 cells were extracted to reconstitute Hsp70-PCs. Maturation of cord blood-derived DC was evaluated by alkaline phosphatase-anti-alkaline phosphatase kit and inverted microscope. The anti-osteosarcoma activity of CTLs evoked by DCs loaded with Hsp70-PCs was determined using Thiazolyl Blue Tetrazolium Bromide (MTT) assay. Results: Hsp70 protein level in BL21 (DE3) increased in a time-dependent manner after induction. The expression of surface markers was upregulated and a typical dendritic morphology was observed in mature DCs. Allogeneic CTLs exhibited strong cytotoxic activity against Saos-2 cells. Conclusion: Our in vitro experiment demonstrated the potent induction of cytotoxic activity against osteosarcoma using DC-based vaccine loaded with Hsp70-PCs.

Genomic analyses of two Alteromonas stellipolaris strains reveal traits with potential biotechnological applications

The Alteromonas stellipolaris strains PQQ-42 and PQQ-44, previously isolated from a fish hatchery, have been selected on the basis of their strong quorum quenching (QQ) activity, as well as their ability to reduce Vibrio-induced mortality on the coral Oculina patagonica. In this study, the genome sequences of both strains were determined and analyzed in order to identify the mechanism responsible for QQ activity. Both PQQ-42 and PQQ-44 were found to degrade a wide range of N-acylhomoserine lactone (AHL) QS signals, possibly due to the presence of an aac gene which encodes an AHL amidohydrolase. In addition, the different colony morphologies exhibited by the strains could be related to the differences observed in genes encoding cell wall biosynthesis and exopolysaccharide (EPS) production. The PQQ-42 strain produces more EPS (0.36 g l-1) than the PQQ-44 strain (0.15 g l-1), whose chemical compositions also differ. Remarkably, PQQ-44 EPS contains large amounts of fucose, a sugar used in high-value biotechnological applications. Furthermore, the genome of strain PQQ-42 contained a large non-ribosomal peptide synthase (NRPS) cluster with a previously unknown genetic structure. The synthesis of enzymes and other bioactive compounds were also identified, indicating that PQQ-42 and PQQ-44 could have biotechnological applications.

Flagellin as a vaccine adjuvant

INTRODUCTION

Bacterial flagellin, as a pathogen-associated molecular pattern (PAMP), can activate both innate and adaptive immunity. Its unique structural characteristics endow an effective and flexible adjuvant activity, which allow the design of different types of vaccine strategies to prevent various diseases. This review will discuss recent progress in the mechanism of action of flagellin and its prospects for use as a vaccine adjuvant.

AREAS COVERED

Herein we summarize various types of information related to flagellin adjuvants from PubMed, including structures, signaling pathways, natural immunity, and extensive applications in vaccines, and it discusses the immunogenicity, safety, and efficacy of flagellin-adjuvanted vaccines in clinical trials.

EXPERT COMMENTARY

It is widely accepted that as an adjuvant, flagellin can induce an enhanced antigen-specific immune response. Flagellin adjuvants will allow more effective flagellin-based vaccines to enter clinical trials. Furthermore, vaccine formulations containing PAMPs are crucial to exert the maximum potential of vaccine antigens. Therefore, combinations of flagellin-adjuvanted vaccines with other adjuvants that act in a synergistic manner, particularly TLR ligands, represent a promising method for tailoring targeted vaccines to meet specific requirements.

Recent advances in cancer immunology and immunology-based anticancer therapies

Cancer immunotherapies offer promise for cure of cancer with specificity and minimal toxicity. Recent developments in cancer immunology have led to the better understanding of role of immune regulatory mechanisms in cancer. There is rapid progress in this field in the last few years. Several clinical studies report the efficacy of immunotherapies for treating cancer. The immunology-based anticancer therapies have shown better safety profiles in clinic as compared to other chemotherapeutic agents, thus increasing interest in this area. This review summarizes recent advances in cancer immunology and discusses tumor microenvironment and immunology-based anticancer therapies, including vaccines and therapies targeting immune checkpoints.

Could mycobacterial Hsp70-containing fusion protein lead the way to an affordable therapeutic cancer vaccine?

Cancer vaccine development efforts have recently gained momentum, but most vaccines showing clinical impact in human trials tend to be based on technology approaches that are very costly and difficult to produce at scale. With the projected doubling of the incidence of cancer and its related cost of care in the U.S. over the next two decades, the widespread clinical use of such vaccines will prove difficult to justify. Heat shock protein-based vaccines have shown the potential to elicit clinically meaningful immunologic responses in cancer, but the predominant development approach - heat shock protein-peptide complexes derived from a patient's own tumor - face similar challenges of cost and scalability. New innovative modalities for deploying heat shock proteins in cancer vaccines may open the door to vaccines that can generate potent cytotoxic responses against multiple tumor targets and can be made in a cost-effective and scalable manner.

The future of glioblastoma therapy: synergism of standard of care and immunotherapy

The current standard of care for glioblastoma (GBM) is maximal surgical resection with adjuvant radiotherapy and temozolomide (TMZ). As the 5-year survival with GBM remains at a dismal <10%, novel therapies are needed. Immunotherapies such as the dendritic cell (DC) vaccine, heat shock protein vaccines, and epidermal growth factor receptor (EGFRvIII) vaccines have shown encouraging results in clinical trials, and have demonstrated synergistic effects with conventional therapeutics resulting in ongoing phase III trials. Chemoradiation has been shown to have synergistic effects when used in combination with immunotherapy. Cytotoxic ionizing radiation is known to trigger pro-inflammatory signaling cascades and immune activation secondary to cell death, which can then be exploited by immunotherapies. The future of GBM therapeutics will involve finding the place for immunotherapy in the current treatment regimen with a focus on developing strategies. Here, we review current GBM therapy and the evidence for combination of immune checkpoint inhibitors, DC and peptide vaccines with the current standard of care.

Anti-cancer Therapies in High Grade Gliomas

High grade gliomas represent one of the most aggressive and treatment-resistant types of human cancer, with only 1–2 years median survival rate for patients with grade IV glioma. The treatment of glioblastoma is a considerable therapeutic challenge; combination therapy targeting multiple pathways is becoming a fast growing area of research. This review offers an up-to-date perspective of the literature about current molecular therapy targets in high grade glioma, that include angiogenic signals, tyrosine kinase receptors, nodal signaling proteins and cancer stem cells related approaches. Simultaneous identification of proteomic signatures could provide biomarker panels for diagnostic and personalized treatment of different subsets of glioblastoma. Personalized medicine is starting to gain importance in clinical care, already having recorded a series of successes in several types of cancer; nonetheless, in brain tumors it is still at an early stage.

Identification of new HLA-A*0201-restricted cytotoxic T lymphocyte epitopes from neuritin

Identification of cytotoxic T lymphocyte (CTL) epitopes from additional tumor antigens is essential for the development of specific immunotherapy of malignant tumors. Neuritin, a recently discovered antigen overexpressed in astrocytoma, is considered to be a promising target for biological therapy. In the present study, we predicted and identified HLA-A2-restricted CTL epitopes from neuritin by using the following four-step procedure: (1) computer-based epitope prediction from the amino acid sequence of neuritin; (2) peptide-binding assay to determine the affinity of the predicted peptide with HLA-A2.1 molecule; (3) stimulation of primary T cell response against the predicted peptides in vitro; and (4) testing of the induced CTLs toward target cells expressing neuritin and HLA-A2.1. The results demonstrated that effectors induced by peptides of neuritin containing residues 13-21, 121-129 and 4-12 could specifically-secrete interferon-γ and lyse target cells. Our results indicate that these peptides are new HLA-A2.1-restricted CTL epitopes, and may serve as valuable tools for astrocytoma immunotherapy.

Cancer immunoediting in malignant glioma

Significant work from many laboratories over the last decade in the study of cancer immunology has resulted in the development of the cancer immunoediting hypothesis. This contemporary framework of the naturally arising immune system-tumor interaction is thought to comprise 3 phases: elimination, wherein immunity subserves an extrinsic tumor suppressor function and destroys nascent tumor cells; equilibrium, wherein tumor cells are constrained in a period of latency under immune control; and escape, wherein tumor cells outpace immunity and progress clinically. In this review, we address in detail the relevance of the cancer immunoediting concept to neurosurgeons and neuro-oncologists treating and studying malignant glioma by exploring the de novo immune response to these tumors, how these tumors may persist in vivo, the mechanisms by which these cells may escape/attenuate immunity, and ultimately how this concept may influence our immunotherapeutic approaches.

Medulloblasoma: challenges for effective immunotherapy

For medulloblastoma patients, the current therapeutic paradigm of surgery followed by radiation and chemotherapy can lead to long-term remission. However, the sequelae of treatment can be very debilitating, particularly in young children. Immunotherapy is an attractive treatment approach to optimize the targeting of tumor cells while sparing the vulnerable surrounding brain that is still developing in children. Understanding the relationship between medulloblastoma and the immune system is critical to develop effective immunologic-based treatment strategies for these patients. This review focuses on current knowledge of tumor immunology and the factors that contribute to the lack of immune system recognition of these tumors. The specificity of tumor antigens present in medulloblastoma is also discussed along with a summary of early clinical immunotherapy results.

Challenges in immunotherapy presented by the glioblastoma multiforme microenvironment

Glioblastoma multiforme (GBM) is the most common and aggressive primary brain tumor in adults. Despite intensive treatment, the prognosis for patients with GBM remains grim with a median survival of only 14.6 months. Immunotherapy has emerged as a promising approach for treating many cancers and affords the advantages of cellular-level specificity and the potential to generate durable immune surveillance. The complexity of the tumor microenvironment poses a significant challenge to the development of immunotherapy for GBM, as multiple signaling pathways, cytokines, and cell types are intricately coordinated to generate an immunosuppressive milieu. The development of new immunotherapy approaches frequently uncovers new mechanisms of tumor-mediated immunosuppression. In this review, we discuss many of the current approaches to immunotherapy and focus on the challenges presented by the tumor microenvironment.

T-cell epitope finding on EPHA2 for further glioma vaccine development: An immunomics study

Background:

Glioma is a deadly neurological tumor. For modern management of glioma, glioma vaccinotherapy is the new concept.

Materials and Methods:

Based on present biomedical technique, the identification of T-cell epitopes via MHC mapping can help clarify the inter-relationship of tumor and immune system. This process can be performed using advanced immunoinformatics technique.

Results:

Here, the author performs an immunoinformatics analysis to find alternative epitopes for glioma-related antigen, EPHA2.

Conclusion:

After complete manipulation on EPHA2 molecules, the five best epitopes were derived.

Assessment of therapeutic response and treatment planning for brain tumors using metabolic and physiological MRI

MRI is routinely used for diagnosis, treatment planning and assessment of response to therapy for patients with glioma. Gliomas are spatially heterogeneous and infiltrative lesions that are quite variable in terms of their response to therapy. Patients classified as having low-grade histology have a median overall survival of 7 years or more, but need to be monitored carefully to make sure that their tumor does not upgrade to a more malignant phenotype. Patients with the most aggressive grade IV histology have a median overall survival of 12-15 months and often undergo multiple surgeries and adjuvant therapies in an attempt to control their disease. Despite improvements in the spatial resolution and sensitivity of anatomic images, there remain considerable ambiguities in the interpretation of changes in the size of the gadolinium-enhancing lesion on T(1) -weighted images as a measure of treatment response, and in differentiating between treatment effects and infiltrating tumor within the larger T(2) lesion. The planning of focal therapies, such as surgery, radiation and targeted drug delivery, as well as a more reliable assessment of the response to therapy, would benefit considerably from the integration of metabolic and physiological imaging techniques into routine clinical MR examinations. Advanced methods that have been shown to provide valuable data for patients with glioma are diffusion, perfusion and spectroscopic imaging. Multiparametric examinations that include the acquisition of such data are able to assess tumor cellularity, hypoxia, disruption of normal tissue architecture, changes in vascular density and vessel permeability, in addition to the standard measures of changes in the volume of enhancing and nonenhancing anatomic lesions. This is particularly critical for the interpretation of the results of Phase I and Phase II clinical trials of novel therapies, which are increasingly including agents that are designed to have anti-angiogenic and anti-proliferative properties as opposed to having a direct effect on tumor cell viability.