Enhanced antitumor immunotherapeutic effect of B-cell-based vaccine transduced with modified adenoviral vector containing type 35 fiber structures

Roles of reactive oxygen species in inflammation and cancer

Reactive oxygen species (ROS) constitute a spectrum of oxygenic metabolites crucial in modulating pathological organism functions. Disruptions in ROS equilibrium span various diseases, and current insights suggest a dual role for ROS in tumorigenesis and the immune response within cancer. This review rigorously examines ROS production and its role in normal cells, elucidating the subsequent regulatory network in inflammation and cancer. Comprehensive synthesis details the documented impacts of ROS on diverse immune cells. Exploring the intricate relationship between ROS and cancer immunity, we highlight its influence on existing immunotherapies, including immune checkpoint blockade, chimeric antigen receptors, and cancer vaccines. Additionally, we underscore the promising prospects of utilizing ROS and targeting ROS modulators as novel immunotherapeutic interventions for cancer. This review discusses the complex interplay between ROS, inflammation, and tumorigenesis, emphasizing the multifaceted functions of ROS in both physiological and pathological conditions. It also underscores the potential implications of ROS in cancer immunotherapy and suggests future research directions, including the development of targeted therapies and precision oncology approaches. In summary, this review emphasizes the significance of understanding ROS-mediated mechanisms for advancing cancer therapy and developing personalized treatments.

Strategy to develop broadly effective multivalent COVID-19 vaccines against emerging variants based on Ad5/35 platform

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron strain has evolved into highly divergent variants with several sub-lineages. These newly emerging variants threaten the efficacy of available COVID-19 vaccines. To mitigate the occurrence of breakthrough infections and re-infections, and more importantly, to reduce the disease burden, it is essential to develop a strategy for producing updated multivalent vaccines that can provide broad neutralization against both currently circulating and emerging variants. We developed bivalent vaccine AdCLD-CoV19-1 BA.5/BA.2.75 and trivalent vaccines AdCLD-CoV19-1 XBB/BN.1/BQ.1.1 and AdCLD-CoV19-1 XBB.1.5/BN.1/BQ.1.1 using an Ad5/35 platform-based non-replicating recombinant adenoviral vector. We compared immune responses elicited by the monovalent and multivalent vaccines in mice and macaques. We found that the BA.5/BA.2.75 bivalent and the XBB/BN.1/BQ.1.1 and XBB.1.5/BN.1/BQ.1.1 trivalent vaccines exhibited improved cross-neutralization ability compared to their respective monovalent vaccines. These data suggest that the developed multivalent vaccines enhance immunity against circulating Omicron subvariants and effectively elicit neutralizing antibodies across a broad spectrum of SARS-CoV-2 variants.

First-in-Human Phase 1 Study of a B Cell- and Monocyte-Based Immunotherapeutic Vaccine against HER2-Positive Advanced Gastric Cancer

PURPOSE

BVAC-B is an autologous B cell- and monocyte-based immunotherapeutic vaccine that contains cells transfected with a recombinant human epidermal growth factor receptor 2 (HER2) gene and loaded with the natural killer T cell ligand alpha-galactosylceramide. Here, we report the first BVAC-B study in patients with HER2-positive advanced gastric cancer.

MATERIALS AND METHODS

Patients with advanced gastric cancer refractory to standard treatment with HER2+ immunohistochemistry ≥ 1 were eligible for treatment. Patients were administered low (2.5×107 cells/dose), medium (5.0×107 cells/dose), or high dose (1.0×108 cells/dose) of BVAC-B intravenously four times every 4 weeks. Primary endpoints included safety and maximum tolerated BVAC-B dose. Secondary endpoints included preliminary clinical efficacy and BVAC-B-induced immune responses.

RESULTS

Eight patients were treated with BVAC-B at low (n=1), medium (n=1), and high doses (n=6). No dose-limiting toxicity was observed, while treatment-related adverse events (TRAEs) were observed in patients treated with medium and high doses. The most common TRAEs were grade 1 (n=2) and grade 2 (n=2) fever. Out of the six patients treated with high-dose BVAC-B, three had stable disease with no response. Interferon gamma, tumor necrosis factor-α, and interleukin-6 increased after BVAC-B treatment in all patients with medium and high dose, and HER2-specific antibody was detected in some patients.

CONCLUSION

BVAC-B monotherapy had a safe toxicity profile with limited clinical activity; however, it activated immune cells in heavily pretreated patients with HER2-positive gastric cancer. Earlier treatment with BVAC-B and combination therapy is warranted for evaluation of clinical efficacy.

Role of reactive oxygen species and mitochondrial damage in rheumatoid arthritis and targeted drugs

Rheumatoid arthritis (RA) is an autoimmune disease characterized by synovial inflammation, pannus formation, and bone and cartilage damage. It has a high disability rate. The hypoxic microenvironment of RA joints can cause reactive oxygen species (ROS) accumulation and mitochondrial damage, which not only affect the metabolic processes of immune cells and pathological changes in fibroblastic synovial cells but also upregulate the expression of several inflammatory pathways, ultimately promoting inflammation. Additionally, ROS and mitochondrial damage are involved in angiogenesis and bone destruction, thereby accelerating RA progression. In this review, we highlighted the effects of ROS accumulation and mitochondrial damage on inflammatory response, angiogenesis, bone and cartilage damage in RA. Additionally, we summarized therapies that target ROS or mitochondria to relieve RA symptoms and discuss the gaps in research and existing controversies, hoping to provide new ideas for research in this area and insights for targeted drug development in RA.

Immunotherapies against HER2-Positive Breast Cancer

Breast cancer is the leading cause of cancer-related deaths among women worldwide. HER2-positive breast cancer, which represents 15-20% of all cases, is characterized by the overexpression of the HER2 receptor. Despite the variety of treatments available for HER2-positive breast cancer, both targeted and untargeted, many patients do not respond to therapy and relapse and eventually metastasize, with a poor prognosis. Immunotherapeutic approaches aim to enhance the antitumor immune response to prevent tumor relapse and metastasis. Several immunotherapies have been approved for solid tumors, but their utility for HER2-positive breast cancer has yet to be confirmed. In this review, we examine the different immunotherapeutic strategies being tested in HER2-positive breast cancer, from long-studied cancer vaccines to immune checkpoint blockade, which targets immune checkpoints in both T cells and tumor cells, as well as the promising adoptive cell therapy in various forms. We discuss how some of these new approaches may contribute to the prevention of tumor progression and be used after standard-of-care therapies for resistant HER2-positive breast tumors, highlighting the benefits and drawbacks of each. We conclude that immunotherapy holds great promise for the treatment of HER2-positive tumors, with the potential to completely eradicate tumor cells and prevent the progression of the disease.

Next-generation antigen-presenting cell immune therapeutics for gliomas

Antigen presentation machinery and professional antigen-presenting cells (APCs) are fundamental for an efficacious immune response against cancers, especially in the context of T cell-centric immunotherapy. Dendritic cells (DCs), the gold standard APCs, play a crucial role in initiating and maintaining a productive antigen-specific adaptive immunity. In recent decades, ex vivo-differentiated DCs from circulating CD14+ monocytes have become the reference for APC-based immunotherapy. DCs loaded with tumor-associated antigens, synthetic peptides, or RNA activate T cells with antitumor properties. This strategy has paved the way for the development of alternative antigen-presenting vaccination strategies, such as monocytes, B cells, and artificial APCs, that have shown effective therapeutic outcomes in preclinical cancer models. The search for alternative APC platforms was initiated by the overall limited clinical impact of DC vaccines, especially in indications such as gliomas, a primary brain tumor known for resistance to any immune intervention. In this Review, we navigate the APC immune therapeutics' past, present, and future in the context of primary brain tumors.

Challenges and opportunities in gene editing of B cells

B cells have long been an underutilized target in immune cell engineering, despite a number of unique attributes that could address longstanding challenges in medicine. Notably, B cells evolved to secrete large quantities of antibodies for prolonged periods, making them suitable platforms for long-term protein delivery. Recent advances in gene editing technologies, such as CRISPR-Cas, have improved the precision and efficiency of engineering and expanded potential applications of engineered B cells. While most work on B cell editing has focused on ex vivo modification, a body of recent work has also advanced the possibility of in vivo editing applications. In this review, we will discuss both past and current approaches to B cell engineering, and its promising applications in immunology research and therapeutic gene editing.

The Chimeric Adenovirus (Ad5/35) Expressing Engineered Spike Protein Confers Immunity against SARS-CoV-2 in Mice and Non-Human Primates

Several COVID-19 platforms have been licensed across the world thus far, but vaccine platform research that can lead to effective antigen delivery is still ongoing. Here, we constructed AdCLD-CoV19 that could modulate humoral immunity by harboring SARS-CoV-2 antigens onto a chimeric adenovirus 5/35 platform that was effective in cellular immunity. By replacing the S1/S2 furin cleavage sequence of the SARS-CoV-2 Spike (S) protein mounted on AdCLD-CoV19 with the linker sequence, high antigen expression was confirmed in various cell lines. The high levels of antigen expression contributed to antigen-specific antibody activity in mice and non-human primates (NHPs) with a single vaccination of AdCLD-CoV19. Furthermore, the adenovirus-induced Th1 immune response was specifically raised for the S protein, and these immune responses protected the NHP against live viruses. While AdCLD-CoV19 maintained neutralizing antibody activity against various SARS-CoV-2 variants, it was reduced to single vaccination for β and ο variants, and the reduced neutralizing antibody activity was restored with booster shots. Hence, AdCLD-CoV19 can prevent SARS-CoV-2 with a single vaccination, and the new vaccine administration strategy that responds to various variants can maintain the efficacy of the vaccine.

Exploiting B Cell Transfer for Cancer Therapy: Engineered B Cells to Eradicate Tumors

Nowadays, cancers still represent a significant health burden, accounting for around 10 million deaths per year, due to ageing populations and inefficient treatments for some refractory cancers. Immunotherapy strategies that modulate the patient's immune system have emerged as good treatment options. Among them, the adoptive transfer of B cells selected ex vivo showed promising results, with a reduction in tumor growth in several cancer mouse models, often associated with antitumoral immune responses. Aside from the benefits of their intrinsic properties, including antigen presentation, antibody secretion, homing and long-term persistence, B cells can be modified prior to reinfusion to increase their therapeutic role. For instance, B cells have been modified mainly to boost their immuno-stimulatory activation potential by forcing the expression of costimulatory ligands using defined culture conditions or gene insertion. Moreover, tumor-specific antigen presentation by infused B cells has been increased by ex vivo antigen loading (peptides, RNA, DNA, virus) or by the sorting/ engineering of B cells with a B cell receptor specific to tumor antigens. Editing of the BCR also rewires B cell specificity toward tumor antigens, and may trigger, upon antigen recognition, the secretion of antitumor antibodies by differentiated plasma cells that can then be recognized by other immune components or cells involved in tumor clearance by antibody-dependent cell cytotoxicity or complement-dependent cytotoxicity for example. With the expansion of gene editing methodologies, new strategies to reprogram immune cells with whole synthetic circuits are being explored: modified B cells can sense disease-specific biomarkers and, in response, trigger the expression of therapeutic molecules, such as molecules that counteract the tumoral immunosuppressive microenvironment. Such strategies remain in their infancy for implementation in B cells, but are likely to expand in the coming years.

Activation of 4-1BBL+ B cells with CD40 agonism and IFNγ elicits potent immunity against glioblastoma

Immunotherapy has revolutionized the treatment of many tumors. However, most glioblastoma (GBM) patients have not, so far, benefited from such successes. With the goal of exploring ways to boost anti-GBM immunity, we developed a B cell-based vaccine (BVax) that consists of 4-1BBL+ B cells activated with CD40 agonism and IFNγ stimulation. BVax migrates to key secondary lymphoid organs and is proficient at antigen cross-presentation, which promotes both the survival and the functionality of CD8+ T cells. A combination of radiation, BVax, and PD-L1 blockade conferred tumor eradication in 80% of treated tumor-bearing animals. This treatment elicited immunological memory that prevented the growth of new tumors upon subsequent reinjection in cured mice. GBM patient-derived BVax was successful in activating autologous CD8+ T cells; these T cells showed a strong ability to kill autologous glioma cells. Our study provides an efficient alternative to current immunotherapeutic approaches that can be readily translated to the clinic.

Vector Strategies to Actualize B Cell-Based Gene Therapies

Recent developments in genome editing and delivery systems have opened new possibilities for B cell gene therapy. CRISPR-Cas9 nucleases have been used to introduce transgenes into B cell genomes for subsequent secretion of exogenous therapeutic proteins from plasma cells and to program novel B cell Ag receptor specificities, allowing for the generation of desirable Ab responses that cannot normally be elicited in animal models. Genome modification of B cells or their progenitor, hematopoietic stem cells, could potentially substitute Ab or protein replacement therapies that require multiple injections over the long term. To date, B cell editing using CRISPR-Cas9 has been solely employed in preclinical studies, in which cells are edited ex vivo. In this review, we discuss current B cell engineering efforts and strategies for the eventual safe and economical adoption of modified B cells into the clinic, including in vivo viral delivery of editing reagents to B cells.

Inhibition of topoisomerase I shapes antitumor immunity through the induction of monocyte-derived dendritic cells

Understanding the rationale of combining immunotherapy and other anticancer treatment modalities is of great interest because of interpatient variability in single-agent immunotherapy. Here, we demonstrated that topoisomerase I inhibitors, a class of chemotherapeutic drugs, can alter the tumor immune landscape, corroborating their antitumor effects combined with immunotherapy. We observed that topotecan-conditioned TC-1 tumors were occupied by a vast number of monocytic cells that highly express CD11c, CD64, and costimulatory molecules responsible for the favorable changes in the tumor microenvironment. Ly6C⁺MHC-II⁺CD11c^hiCD64^hi cells, referred to as topotecan-induced monocyte-derived dendritic cells (moDCs), proliferate and activate antigen-specific CD8⁺ T cells to levels equivalent to those of conventional DCs. Phenotypic changes in Ly6C⁺ cells towards moDCs were similarly induced by exposure to topotecan in vitro, which was more profoundly facilitated in the presence of tumor cells. Notably, anti-M-CSFR reversed the acquisition of DC-like properties of topotecan-induced moDCs, leading to the abolition of the antitumor effect of topotecan combined with a cancer vaccine. In short, topoisomerase I inhibitors generate monocyte-derived antigen-presenting cells in tumors, which could be mediated by M-CSF-M-CSFR signaling.

Antigen-specific tolerance approach for rheumatoid arthritis: Past, present and future

Rheumatoid arthritis is a chronic systemic autoimmune disease, affecting mainly the joints. It is caused by an adaptive immune reaction against self-antigens, leading to the over production of inflammatory cytokines and autoantibodies, mainly mediated by autoreactive CD4+ T cells and pathological B cell clones. The treatment options currently available rely on palliative global immunosuppression and do not restore tolerance to self-components. Here, we review antigen-specific tolerance approaches that have been developed to inhibit or delete autoreactive clones, while maintaining a potent immune system for rheumatoid arthritis. The first attempts relied on the oral ingestion of self-reactive peptides, with lukewarm results in human clinical trials. To enhance treatment efficacy, self-peptides have been engineered and combined with immunosuppressive molecules. In addition, several routes of delivery have been tested, in particular, nanoparticles carrying self-antigens and immunomodulatory molecules. More recently, transfer of immune cells, such as tolerogenic dendritic cells or regulatory T cells, has been considered to restore tolerance. Although promising results have been obtained in mouse models, the translation to humans remains highly challenging, mainly because the disease is already well developed when treatments start and because patient's specific self-antigens are often unknown. Nevertheless, these approaches hold great promises for long-term RA treatment.

Enhanced Immunogenicity of Engineered HER2 Antigens Potentiates Antitumor Immune Responses

For cancer vaccines, the selection of optimal tumor-associated antigens (TAAs) that can maximize the immunogenicity of the vaccine without causing unwanted adverse effects is challenging. In this study, we developed two engineered Human epidermal growth factor receptor 2 (HER2) antigens, K965 and K1117, and compared their immunogenicity to a previously reported truncated HER2 antigen, K684, within a B cell and monocyte-based vaccine (BVAC). We found that BVAC-K965 and BVAC-K1117 induced comparable antigen-specific antibody responses and antigen-specific T cell responses to BVAC-K684. Interestingly, BVAC-K1117 induced more potent antitumor activity than the other vaccines in murine CT26-HER2 tumor models. In addition, BVAC-K1117 showed enhanced antitumor effects against truncated p95HER2-expressing CT26 tumors compared to BVAC-K965 and BVAC-K684 based on the survival analysis by inducing T cell responses against intracellular domain (ICD) epitopes. The increased ICD epitope-specific T cell responses induced by BVAC-K1117 compared to BVAC-K965 and BVAC-K684 were recapitulated in human leukocyte antigen (HLA)-untyped human PBMCs and HLA-A*0201 PBMCs. Furthermore, we also observed synergistic antitumor effects between BVAC-K1117 and anti-PD-L1 antibody treatment against CT26-HER2 tumors. Collectively, our findings demonstrate that inclusion of a sufficient number of ICD epitopes of HER2 in cellular vaccines can improve the antitumor activity of the vaccine and provide a way to optimize the efficacy of anticancer cellular vaccines targeting HER2.

HER2-Positive Breast Cancer Immunotherapy: A Focus on Vaccine Development

Clinical progress in the field of HER2-positive breast cancer therapy has been dramatically improved by understanding of the immune regulatory mechanisms of tumor microenvironment. Passive immunotherapy utilizing recombinant monoclonal antibodies (mAbs), particularly trastuzumab and pertuzumab has proved to be an effective strategy in HER2-positive breast cancer treatment. However, resistance to mAb therapy and relapse of disease are still considered important challenges in clinical practice. There are increasing reports on the induction of cellular and humoral immune responses in HER2-positive breast cancer patients. More recently, increasing efforts are focused on using HER2-derived peptide vaccines for active immunotherapy. Here, we discuss the development of various HER2-derived vaccines tested in animal models and human clinical trials. Different formulations and strategies to improve immunogenicity of the antigens in animal studies are also discussed. Furthermore, other immunotherapeutic approaches to HER2 breast cancer including, CTLA-4 inhibitors, immune checkpoint inhibitors, anti PD-1/PD-L1 antibodies are presented.

Molecular Design, Optimization, and Genomic Integration of Chimeric B Cell Receptors in Murine B Cells

Immune cell therapies based on the integration of synthetic antigen receptors comprise a powerful strategy for the treatment of diverse diseases, most notably T cells engineered to express chimeric antigen receptors (CAR) for targeted cancer therapy. In addition to T lymphocytes, B lymphocytes may also represent valuable immune cells that can be engineered for therapeutic purposes such as protein replacement therapy or recombinant antibody production. In this article, we report a promising concept for the molecular design, optimization, and genomic integration of a novel class of synthetic antigen receptors, chimeric B cell receptors (CBCR). We initially optimized CBCR expression and detection by modifying the extracellular surface tag, the transmembrane regions and intracellular signaling domains. For this purpose, we stably integrated a series of CBCR variants using CRISPR-Cas9 into immortalized B cell hybridomas. Subsequently, we developed a reliable and consistent pipeline to precisely introduce cassettes of several kb size into the genome of primary murine B cells also using CRISPR-Cas9 induced HDR. Finally, we were able to show the robust surface expression and antigen recognition of a synthetic CBCR in primary B cells. We anticipate CBCRs and our approach for engineering primary B cells will be a valuable tool for the advancement of future B cell- based immune cell therapies.

Reactive oxygen species: The signal regulator of B cell

Reactive oxygen species (ROS) are indispensable for determining the fate of immune cells in both physiological and pathogenic environments, thus stimulating the interest of immunologists and clinicians. B cells are essential in maintaining immune homeostasis, and studies have indicated that ROS affect the maturation, activation and differentiation of B cells by controlling the signaling molecules in various molecular pathways. In the present review, we aimed to summarize the biological properties of ROS and the mechanisms by which ROS regulate B cell signaling pathways. We propose that ROS and their mediated signal transduction can be a new approach for manipulating B cell immune functions.

Activation of NKT Cells in an Anti-PD-1-Resistant Tumor Model Enhances Antitumor Immunity by Reinvigorating Exhausted CD8 T Cells

PD-1-based cancer immunotherapy is a successful example of immune checkpoint blockade that provides long-term durable therapeutic effects in patients with cancer across a wide spectrum of cancer types. Accumulating evidence suggests that anti-PD-1 therapy enhances antitumor immunity by reversing the function of exhausted T cells in the tumor environment. However, the responsiveness rate of patients with cancer to anti-PD-1 therapy remains low, providing an urgent need for optimization and improvement. In this study, we designed an anti-PD-1-resistant mouse tumor model and showed that unresponsiveness to anti-PD-1 is associated with a gradual increase in CD8 T-cell exhaustion. We also found that invariant natural killer T cell stimulation by the synthetic ligand α-galactosylceramide (αGC) can enhance the antitumor effect in anti-PD-1-resistant tumors by restoring the effector function of tumor antigen-specific exhausted CD8 T cells. IL2 and IL12 were among the cytokines produced by αGC stimulation critical for reinvigorating exhausted CD8 T cells in tumor-bearing mice and patients with cancer. Furthermore, we observed a synergistic increase in the antitumor effect between αGC-loaded antigen-presenting cells and PD-1 blockade in a therapeutic murine tumor model. Our study suggests NKT cell stimulation as a promising therapeutic strategy for the treatment of patients with anti-PD-1-resistant cancer.Significance: These findings provide mechanistic insights into the application of NKT cell stimulation as a potent adjuvant for immunotherapy against advanced cancer. Cancer Res; 78(18); 5315-26. ©2018 AACR.

IL21 Therapy Combined with PD-1 and Tim-3 Blockade Provides Enhanced NK Cell Antitumor Activity against MHC Class I-Deficient Tumors

Increased expression of coinhibitory molecules such as PD-1 and Tim-3 on NK cells has been demonstrated in advanced cancer patients who harbor MHC class I-deficient tumors. However, even in preclinical models, the antitumor effects of checkpoint blockade on NK cells have not been clearly elucidated. Here, we show that anti-PD-1/anti-Tim-3 treatment suppressed tumor progression in mice bearing MHC class I-deficient tumors, and the suppression was further enhanced by recombinant IL21 (rIL21) treatments through an NK-cell-dependent mechanism. We also show that the intratumoral delivery of rIL21 attracted NK cells to the tumor site in a CXCR3-dependent fashion. A combination of IL21 and checkpoint blockade facilitated the effector function of exhausted NK cells in cancer patients. Given the effects of the checkpoint blockade and rIL21 combination on NK cells infiltrating into MHC class I-deficient tumors, we suggest that the efficacy of checkpoint blockade can be enhanced through the administration of IL21 for advanced cancer patients with MHC class I-low/deficient tumors. Cancer Immunol Res; 6(6); 685-95. ©2018 AACR.

Engineering Protein-Secreting Plasma Cells by Homology-Directed Repair in Primary Human B Cells

The ability to engineer primary human B cells to differentiate into long-lived plasma cells and secrete a de novo protein may allow the creation of novel plasma cell therapies for protein deficiency diseases and other clinical applications. We initially developed methods for efficient genome editing of primary B cells isolated from peripheral blood. By delivering CRISPR/CRISPR-associated protein 9 (Cas9) ribonucleoprotein (RNP) complexes under conditions of rapid B cell expansion, we achieved site-specific gene disruption at multiple loci in primary human B cells (with editing rates of up to 94%). We used this method to alter ex vivo plasma cell differentiation by disrupting developmental regulatory genes. Next, we co-delivered RNPs with either a single-stranded DNA oligonucleotide or adeno-associated viruses containing homologous repair templates. Using either delivery method, we achieved targeted sequence integration at high efficiency (up to 40%) via homology-directed repair. This method enabled us to engineer plasma cells to secrete factor IX (FIX) or B cell activating factor (BAFF) at high levels. Finally, we show that introduction of BAFF into plasma cells promotes their engraftment into immunodeficient mice. Our results highlight the utility of genome editing in studying human B cell biology and demonstrate a novel strategy for modifying human plasma cells to secrete therapeutic proteins.

Potent antitumor effect of tumor microenvironment-targeted oncolytic adenovirus against desmoplastic pancreatic cancer

Pancreatic cancer is a leading cause of cancer-related death. Desmoplastic pancreatic tumors exhibit excessive extracellular matrix (ECM) and are thus highly resistant to anticancer therapeutics, since the ECM restricts drug penetration and dispersion. Here, we designed and generated two hypoxia-responsive and cancer-specific hybrid promoters, H(mT)E and H(E)mT. Transgene expression driven by each hybrid promoter was markedly higher under hypoxic conditions than normoxic conditions. Moreover, H(E)mT-driven transgene expression was highly cancer-specific and was superior to that of H(mT)E-driven expression. A decorin-expressing oncolytic adenovirus (Ad; oH(E)mT-DCN) replicating under the control of the H(E)mT promoter induced more potent and highly cancer-specific cell death compared with its cognate control oncolytic Ad, which harbored the endogenous Ad E1A promoter. Moreover, oH(E)mT-DCN exhibited enhanced antitumor efficacy compared with both the clinically approved oncolytic Ad ONYX-015 and its cognate control oncolytic Ad lacking DCN. oH(E)mT-DCN treatment also attenuated the expression of major ECM components, such as collagen I/III, elastin and fibronectin and induced tumor cell apoptosis, leading to extensive viral dispersion within orthotopic pancreatic tumors and pancreatic cancer patient-derived tumor spheroids. Collectively, these findings demonstrate that oH(E)mT-DCN exhibits potent antitumor efficacy by degrading the ECM and inducing apoptosis in a multifunctional process. This process facilitates the dispersion and replication of oncolytic Ad, making it an attractive candidate for the treatment of aggressive and desmoplastic pancreatic cancer.

Combination of DESI2 and IP10 gene therapy significantly improves therapeutic efficacy against murine carcinoma

DESI2 (also known as PNAS-4) is a novel pro-apoptotic gene activated during the early response to DNA damage. We previously reported that overexpression of DESI2 induces S phase arrest and apoptosis by activating checkpoint kinases. The present study was designed to test whether combination of DESI2 and IP10 could improve the therapy efficacy in vitro and in vivo. The recombinant plasmid co-expressing DESI2 and IP10 was encapsulated with DOTAP/Cholesterol nanoparticle. Immunocompetent mice bearing CT26 colon carcinoma and LL2 lung cancer were treated with the complex. We found that, in vitro, the combination of DESI2 and IP10 more efficiently inhibited proliferation of CT26, LL2, SKOV3 and A549 cancer cells via apoptosis. In vivo, the combined gene therapy more significantly inhibited tumor growth and efficiently prolonged the survival of tumor bearing mice. Mechanistically, the augmented antitumor activity in vivo was associated with induction of apoptosis and inhibition of angiogenesis. The anti-angiogenesis was further mimicked by inhibiting proliferation of immortalized HUVEC cells in vitro. Meanwhile, the infiltration of lymphocytes also contributed to the enhanced antitumor effects. Depletion of CD8+ T lymphocytes significantly abrogated the antitumor activity, whereas depletion of CD4+ T cells or NK cells showed partial abrogation. Our data suggest that the combined gene therapy of DESI2 and IP10 can significantly enhance the antitumor activity as apoptosis inducer, angiogenesis inhibitor and immune response initiator. The present study may provide a novel and effective method for treating cancer.

IL-21-mediated reversal of NK cell exhaustion facilitates anti-tumour immunity in MHC class I-deficient tumours

During cancer immunoediting, loss of major histocompatibility complex class I (MHC-I) in neoplasm contributes to the evasion of tumours from host immune system. Recent studies have demonstrated that most natural killer (NK) cells that are found in advanced cancers are defective, releasing the malignant MHC-I-deficient tumours from NK-cell-dependent immune control. Here, we show that a natural killer T (NKT)-cell-ligand-loaded tumour-antigen expressing antigen-presenting cell (APC)-based vaccine effectively eradicates these advanced tumours. During this process, we find that the co-expression of Tim-3 and PD-1 marks functionally exhausted NK cells in advanced tumours and that MHC-I downregulation in tumours is closely associated with the induction of NK-cell exhaustion in both tumour-bearing mice and cancer patients. Furthermore, the recovery of NK-cell function by IL-21 is critical for the anti-tumour effects of the vaccine against advanced tumours. These results reveal the process involved in the induction of NK-cell dysfunction in advanced cancers and provide a guidance for the development of strategies for cancer immunotherapy.

Loss of major histocompatibility complex MHC-I expression contributes to cancer immune evasion. Here, the authors show that, in both mice and humans, MHC-I downregulation is associated with the induction of NK-cell exhaustion and that IL-21 restores NK-cell function and inhibits tumours progression.

Mild Hyperthermia Induced by Gold Nanorod-Mediated Plasmonic Photothermal Therapy Enhances Transduction and Replication of Oncolytic Adenoviral Gene Delivery

Oncolytic adenovirus (Ad) is a promising candidate for cancer gene therapy. However, as a monotherapy, it has shown insufficient therapeutic efficacy in clinical trials. In this work, we demonstrate that gold nanorod (GNR)-mediated mild hyperthermia enhances the cellular uptake and consequent gene expression of oncolytic Ad to head and neck tumor cells. We examined the combination of oncolytic Ad expressing vascular endothelial growth factor promoter-targeted artificial transcriptional repressor zinc-finger protein and GNR-mediated mild hyperthermia to improve antitumor effects. The in vitro mechanisms of increased transduction in the presence and absence of hyperthermia were explored followed by evaluation of efficacy of this combination strategy in an animal model. Exposure to optimized hyperthermia conditions improved endocytosis of oncolytic Ad, transgene expression, viral replication, and subsequent cytolysis of head and neck cancer cells. GNR-mediated plasmonic photothermal therapy resulted in precise control of tumor temperature and induction of mild hyperthermia. A combination of oncolytic Ad and GNRs resulted in potent tumor growth inhibition of head and neck tumors.

Progresses towards safe and efficient gene therapy vectors

The emergence of genetic engineering at the beginning of the 1970′s opened the era of biomedical technologies, which aims to improve human health using genetic manipulation techniques in a clinical context. Gene therapy represents an innovating and appealing strategy for treatment of human diseases, which utilizes vehicles or vectors for delivering therapeutic genes into the patients' body. However, a few past unsuccessful events that negatively marked the beginning of gene therapy resulted in the need for further studies regarding the design and biology of gene therapy vectors, so that this innovating treatment approach can successfully move from bench to bedside. In this paper, we review the major gene delivery vectors and recent improvements made in their design meant to overcome the issues that commonly arise with the use of gene therapy vectors. At the end of the manuscript, we summarized the main advantages and disadvantages of common gene therapy vectors and we discuss possible future directions for potential therapeutic vectors.

The double-edge role of B cells in mediating antitumor T-cell immunity: Pharmacological strategies for cancer immunotherapy

Emerging evidence reveals the controversial role of B cells in antitumor immunity, but the underlying mechanisms have to be explored. Three latest articles published in the issue 521 of Nature in 2015 reconfirmed the puzzling topic and put forward some explanations of how B cells regulate antitumor T-cell responses both positively and negatively. This paper attempts to demonstrate that different B-cell subpopulations have distinct immunological properties and that they are involved in either antitumor responses or immunosuppression. Recent studies supporting the positive and negative roles of B cells in tumor development were summarized comprehensively. Several specific B-cell subpopulations, such as IgG(+), IgA(+), IL-10(+), and regulatory B cells, were described in detail. The mechanisms underlying the controversial B-cell effects were mainly attributed to different B-cell subpopulations, different B-cell-derived cytokines, direct B cell-T cell interaction, different cancer categories, and different malignant stages, and the immunological interaction between B cells and T cells is mediated by dendritic cells. Promising B-cell-based antitumor strategies were proposed and novel B-cell regulators were summarized to present interesting therapeutic targets. Future investigations are needed to make sure that B-cell-based pharmacological strategies benefit cancer immunotherapy substantially.

Tumor-derived osteopontin suppresses antitumor immunity by promoting extramedullary myelopoiesis

Extramedullary myelopoiesis occurs commonly in tumor-bearing animals and is known to lead to accumulation of peripheral myeloid-derived suppressor cells (MDSC), which play an important role in immune escape. However, the cellular and molecular mechanisms by which tumors induce extramedullary myelopoiesis are poorly understood. In this study, we found that osteopontin expressed by tumor cells enhances extramedullary myelopoiesis in a CD44-dependent manner through the Erk1/2-MAPK pathway. Osteopontin-mediated extramedullary myelopoiesis was directly associated with increased MDSCs in tumor-bearing hosts. More importantly, osteopontin silencing in tumor cells delayed both tumor growth and extramedullary myelopoiesis, while the same treatment did not affect tumor growth in vitro. Finally, treatment with an antibody against osteopontin inhibited tumor growth and synergized with cell-based immunotherapeutic vaccines in mediating antitumor immunity. Our findings unveil a novel immunosuppressive role for tumor-derived osteopontin and offer a rationale for its therapeutic targeting in cancer treatment.