Search

Simple Summary: Recent advancements in cancer research have proven immunotherapies to be a promising strategy for the treatment of hematological malignancies. The bispecific antibody (BsAb) format was developed to overcome the issues of monoclonal antibody-based therapies. T-cell engagers (TCEs) are BsAbs, which directly activate T-cells and their anti-tumor features, ultimately resulting in the lysis of the targeted tumor cells. In 2014, the FDA approved blinatumomab for treatment of acute lymphoblastic leukemia. As of November 2023, seven clinically approved TCE therapies are on the market. In this paper, we summarized the technical basis of the TCE technology, its application in hematology, and its current issues and prospects. Recent advancements in cancer immunotherapy have made directing the cellular immune response onto cancer cells a promising strategy for the treatment of hematological malignancies. The introduction of monoclonal antibody-based (mAbs) targeted therapy has significantly improved the prognosis for hematological patients. Facing the issues of mAb-based therapies, a novel bispecific antibody (BsAb) format was developed. T-cell engagers (TCEs) are BsAbs, which simultaneously target tumor-associated antigens on tumor cells and CD3 molecules present on T-cells. This mechanism allows for the direct activation of T-cells and their anti-tumor features, ultimately resulting in the lysis of tumor cells. In 2014, the FDA approved blinatumomab, a TCE directed to CD3 and CD19 for treatment of acute lymphoblastic leukemia. Since then, numerous TCEs have been developed, allowing for treating different hematological malignancies such as acute myeloid leukemia, multiple myeloma, and non-Hodgkin lymphoma and Hodgkin lymphoma. As of November 2023, seven clinically approved TCE therapies are on the market. TCE-based therapies still have their limitations; however, improving the properties of TCEs, as well as combining TCE-based therapies with other forms of treatment, give hope to find the cures for currently terminal diseases. In this paper, we summarized the technical basis of the TCE technology, its application in hematology, and its current issues and prospects. [ABSTRACT FROM AUTHOR]

The recognition of smoking as an independent risk factor for lung cancer has become a widely accepted within the realm of respiratory medicine. The emergence of tumor immunotherapy has notably enhanced the prognosis for numerous late-stage cancer patients. Nevertheless, some studies have noted a tendency for lung cancer patients who smoke to derive greater benefit from immunotherapy. This observation has sparked increased interest in the interaction between smoking and the immune response to tumors in lung cancer. The concept of cancer immunoediting has shed light on the intricate and nuanced relationship between the immune system and tumors. Starting from the perspectives of immune surveillance, immune equilibrium, and immune evasion, this narrative review explores how smoking undermines the immune response against tumor cells and induces the generation of tumor neoantigens, and examines other behaviors that trigger tumor immune evasion. By elucidating these aspects, the review concludes that smoking is not conducive to tumor immunoediting. [ABSTRACT FROM AUTHOR]

Simple Summary: Cancer in the head and neck region (HNSCC) is exponentially increasing due to human papillomavirus (HPV) infections. This paper helps us to understand the complexity of the inflammatory networks and the mechanisms of immune evasion in HPV+ HNSCC to open up new avenues and drive the discovery of useful tools to be translated clinically in the screening and treatment of these cases, especially to overcome resistance and improve patients' quality of life. Head and neck squamous cell carcinomas (HNSCC) are a heterogeneous group of malignancies which have shown exponential incidence in the last two decades especially due to human papillomavirus (HPV) infection. The HPV family comprises more than 100 types of viruses with HPV16 and HPV18 being the most prevalent strains in HNSCC. Literature data reveal that the mutation profile as well as the response to chemotherapy and radiotherapy are distinct among HPV+ versus HPV-negative tumors. Furthermore, the presence of the virus induces activation of an immune response, in particular the recruitment of specific antiviral T lymphocytes to tumor sites. These T cells when activated produce soluble factors including cytokines and chemokines capable of modifying the local immune tumor microenvironment and impact on tumor response to the treatment. In this comprehensive review we investigated current knowledge on how the presence of an HPV can modify the inflammatory response systemically and within the tumor microenvironment's immunological responses, thereby impacting on disease prognosis and survival. We highlighted the research gaps and emerging approaches necessary to discover novel immunotherapeutic targets for HPV-associated HNSCC. [ABSTRACT FROM AUTHOR]

Simple Summary: Immune checkpoint inhibitors (ICIs) are cancer immunotherapeutics that reinvigorate immune cells' ability to attack tumor cells. Despite remarkable results in some patients, ICIs do not demonstrate the same efficacy across all individuals. In this study, we present the first side-by-side comparison of an agent-based model (ABM) with an ordinary differential equation (ODE) model for ICIs targeting the PD-1/PD-L1 immune checkpoint. We consider tumor cells of high and low antigenicity and two distinct immune-cell kill mechanisms. Using key parameters calibrated from mouse bladder cancer studies, we simulate virtual tumors using both models. Our research identifies crucial tumor-immune characteristics that influence the efficacy of ICIs. By exploring the unique spatial insights provided by the ABM, we underscore the importance of considering the spatial complexity of the tumor microenvironment in mathematical models of ICIs, potentially paving the way for more effective cancer treatments. Since the introduction of the first immune checkpoint inhibitor (ICI), immunotherapy has changed the landscape of molecular therapeutics for cancers. However, ICIs do not work equally well on all cancers and for all patients. There has been a growing interest in using mathematical and computational models to optimize clinical responses. Ordinary differential equations (ODEs) have been widely used for mechanistic modeling in immuno-oncology and immunotherapy. They allow rapid simulations of temporal changes in the cellular and molecular populations involved. Nonetheless, ODEs cannot describe the spatial structure in the tumor microenvironment or quantify the influence of spatially-dependent characteristics of tumor-immune dynamics. For these reasons, agent-based models (ABMs) have gained popularity because they can model more detailed phenotypic and spatial heterogeneity that better reflect the complexity seen in vivo. In the context of anti-PD-1 ICIs, we compare treatment outcomes simulated from an ODE model and an ABM to show the importance of including spatial components in computational models of cancer immunotherapy. We consider tumor cells of high and low antigenicity and two distinct cytotoxic T lymphocyte (CTL) killing mechanisms. The preferred mechanism differs based on the antigenicity of tumor cells. Our ABM reveals varied phenotypic shifts within the tumor and spatial organization of tumor and CTLs despite similarities in key immune parameters, initial simulation conditions, and early temporal trajectories of the cell populations. [ABSTRACT FROM AUTHOR]

Dendritic cells (DCs) 'pulsed' with an appropriate antigen may elicit an antitumour immune response in mouse models. However, while attempting to develop a DC immunotherapy protocol for the treatment of breast cancer based on the tumour-associated MUC1 glycoforms, we found that unpulsed DCs can affect tumour growth. Protection from RMA-MUC1 tumour challenge was achieved in C57Bl/6 MUC1 transgenic mice by immunising with syngeneic DCs pulsed with a MUC1 peptide. However, unpulsed DCs gave a similar level of protection, making it impossible to evaluate the effect of immunisation of mice with DCs pulsed with the specific peptide. Balb/C mice could also be protected from tumour challenge by immunisation with unpulsed DCs prior to challenge with murine mammary tumour cells (410.4) or these cells transfected with MUC1 (E3). Protection was achieved with as few as three injections of 50,000 naïve DCs per mouse per week, was not dependent on injection route, and was not specific to cell lines expressing human MUC1. However, the use of Rag2-knockout mice demonstrated that the adaptive immune response was required for tumour rejection. Injection of unpulsed DCs into mice bearing the E3 tumour slowed tumour growth. In vitro, production of IFN-gamma and IL-4 was increased in splenic cells isolated from mice immunised with DCs. Depleting CD4 T cells in vitro partially decreased cytokine production by splenocytes, but CD8 depletion had no effect. This paper shows that naïve syngeneic DCs may induce an antitumour immune response and has implications for DC immunotherapy preclinical and clinical trials. [ABSTRACT FROM AUTHOR]

Simple Summary: As computer performance continues to grow at more affordable costs, mathematical modelling and in silico experimentation begin to play a larger role in understanding cancer evolution. The aim of our work is to formulate a control strategy for the Adaptive Cellular Therapy (ACT) that can fully eradicates the Chronic Myelogenous Leukemia (CML) cells population in a mathematical model describing interactions between naive T cells, effector T cells and CML cancer cells in the circulatory blood system. Mathematical analysis and numerical simulations allow us to conclude that it is possible to design a personalized administration protocol for the ACT in the form of a pulse train with asymmetrical waves and a fixed amplitude to achieve complete CML cancer cells eradication. The amplitude of the impulse on which the treatment is applied is given by an arithmetical combination of the parameters of the system with at least a duty cycle of 45 min/day. This paper is devoted to exploring personalized applications of cellular immunotherapy as a control strategy for the treatment of chronic myelogenous leukemia described by a dynamical system of three first-order ordinary differential equations. The latter was achieved by applying both the Localization of Compact Invariant Sets and Lyapunov's stability theory. Combination of these two approaches allows us to establish sufficient conditions on the immunotherapy treatment parameter to ensure the complete eradication of the leukemia cancer cells. These conditions are given in terms of the system parameters and by performing several in silico experimentations, we formulated a protocol for the therapy application that completely eradicates the leukemia cancer cells population for different initial tumour concentrations. The formulated protocol does not dangerously increase the effector T cells population. Further, complete eradication is considered when solutions go below a finite critical value below which cancer cells cannot longer persist; i.e., one cancer cell. Numerical simulations are consistent with our analytical results. [ABSTRACT FROM AUTHOR]

This paper investigates the Vβ usage of lymph node cells from mice immunized with TNP and of cell lines made from them. In cell lines stimulated weekly with TNP in vitro for 1 month, about 87% of the cells were Vβ8+ and further analysis showed that these cells were actually Vβ.2+. This was also true for the cells that proliferated in lymph nodes in response to TNP 4 days after primary immunization, i.e. proliferation occurred mainly in the Vβ+, and in particular in the Vβ8.2+, population while much less proliferation occurred when the Vβ8- or Vβ8.2- T-cell populations are used. This was not due to non-specific damage during separation, as the response to concanavalin A and alloantigen was intact. In a separate series of experiments, mice were acutely depleted of Vβ8+ T cells by treatment with F23.1 or a control monoclonal antibody (mAb) in vivo given before immunization. Treatment with the relevant mAb virtually abolished the response to TNP. In contrast, SJL mice, which lack the gone segment coding for the Vβ8 family and several other Vβ chains, made a normal proliferative and delayed-type hypersensitivity (DTH) response to TNP. This poses the problem, which may he important in the study of the T-cell repertoire, of why acute removal of Vβ8+ T cells, which are dominantly used in the response to TNP, does not allow T cells using other chains to substitute in the response, while the absence of this population over a long period of time, because of a deletion in the genome, allows the use of T cells hearing other Vβ chains. [ABSTRACT FROM AUTHOR]

Simple Summary: The receptor tyrosine kinase Axl is upregulated in up to 40% of hepatocellular carcinoma (HCC) cases correlating with an unfavorable prognosis. It is an open issue how Axl and its ligand Gas6 drive disease development at a molecular level. The aim of this study was to identify target genes of Gas6/Axl and to assess their contribution to HCC progression. One of the targets is the cancer-testis antigen PRAME (preferentially expressed antigen in melanoma), which is currently exploited for its capacity in T cell-based immunotherapy. We show that PRAME induces hepatic dedifferentiation, epithelial-to-mesenchymal transition and invasiveness in liver cancer cells. Together, these data provide evidence that PRAME is induced by the Gas6/Axl/Mek/Erk1/2 signaling axis and exerts pro-oncogenic functions in HCC. (1) Background: Activation of the receptor tyrosine kinase Axl by Gas6 fosters oncogenic effects in hepatocellular carcinoma (HCC), associating with increased mortality of patients. The impact of Gas6/Axl signaling on the induction of individual target genes in HCC and its consequences is an open issue. (2) Methods: RNA-seq analysis of Gas6-stimulated Axl-proficient or Axl-deficient HCC cells was used to identify Gas6/Axl targets. Gain- and loss-of-function studies as well as proteomics were employed to characterize the role of PRAME (preferentially expressed antigen in melanoma). Expression of Axl/PRAME was assessed in publicly available HCC patient datasets and in 133 HCC cases. (3) Results: Exploitation of well-characterized HCC models expressing Axl or devoid of Axl allowed the identification of target genes including PRAME. Intervention with Axl signaling or MAPK/ERK1/2 resulted in reduced PRAME expression. PRAME levels were associated with a mesenchymal-like phenotype augmenting 2D cell migration and 3D cell invasion. Interactions with pro-oncogenic proteins such as CCAR1 suggested further tumor-promoting functions of PRAME in HCC. Moreover, PRAME showed elevated expression in Axl-stratified HCC patients, which correlates with vascular invasion and lowered patient survival. (4) Conclusions: PRAME is a bona fide target of Gas6/Axl/ERK signaling linked to EMT and cancer cell invasion in HCC. [ABSTRACT FROM AUTHOR]

Simple Summary: According to the latest GLOBOCAN data, head and neck squamous cell carcinoma (HNSCC) represents the sixth most prevalent human malignancy. Recent studies indicate that various immune cell populations may determine the pathogenesis of HNSCCs. The aim of this review was to provide a comprehensive overview of the role of the immune response in HNSCC tumorigenesis, molecular signatures and the mechanisms regulating pro- and anti-cancer activity; it also examines their impact on the current status and future prospects of immunotherapeutic strategies for overcoming immune escape of HNSCC. The study corpus encompasses a wide range of recent molecular, observational and intervention studies on the role of immune signalling pathways and interaction between neoplastic cells and immune cells in human HNSCCs. Rapid advances in the field of immuno-oncology and the constantly growing body of knowledge concerning immunosuppressive mechanisms have allowed effective and personalized immunotherapy to be used as a first-line therapeutic procedure or an essential component of a combination therapy for primary, relapsed and metastatic HNSCC. A greater understanding of the immune response in cancers may also contribute to the further identification of new potential immunological biomarkers necessary for greater clinical benefit in HNSCC patients. Head and neck squamous cell carcinoma (HNSCC) is one of the most aggressive and heterogeneous groups of human neoplasms. HNSCC is characterized by high morbidity, accounting for 3% of all cancers, and high mortality with ~1.5% of all cancer deaths. It was the most common cancer worldwide in 2020, according to the latest GLOBOCAN data, representing the seventh most prevalent human malignancy. Despite great advances in surgical techniques and the application of modern combinations and cytotoxic therapies, HNSCC remains a leading cause of death worldwide with a low overall survival rate not exceeding 40–60% of the patient population. The most common causes of death in patients are its frequent nodal metastases and local neoplastic recurrences, as well as the relatively low response to treatment and severe drug resistance. Much evidence suggests that the tumour microenvironment (TME), tumour infiltrating lymphocytes (TILs) and circulating various subpopulations of immunocompetent cells, such regulatory T cells (CD4+CD25+Foxp3+Tregs), cytotoxic CD3+CD8+ T cells (CTLs) and CD3+CD4+ T helper type 1/2/9/17 (Th1/Th2/Th9/Th17) lymphocytes, T follicular helper cells (Tfh) and CD56dim/CD16bright activated natural killer cells (NK), carcinoma-associated fibroblasts (CAFs), myeloid-derived suppressor cells (MDSCs), tumour-associated neutrophils (N1/N2 TANs), as well as tumour-associated macrophages (M1/M2 phenotype TAMs) can affect initiation, progression and spread of HNSCC and determine the response to immunotherapy. Rapid advances in the field of immuno-oncology and the constantly growing knowledge of the immunosuppressive mechanisms and effects of tumour cancer have allowed for the use of effective and personalized immunotherapy as a first-line therapeutic procedure or an essential component of a combination therapy for primary, relapsed and metastatic HNSCC. This review presents the latest reports and molecular studies regarding the anti-tumour role of selected subpopulations of immunocompetent cells in the pathogenesis of HNSCC, including HPV+ve (HPV+) and HPV−ve (HPV−) tumours. The article focuses on the crucial regulatory mechanisms of pro- and anti-tumour activity, key genetic or epigenetic changes that favour tumour immune escape, and the strategies that the tumour employs to avoid recognition by immunocompetent cells, as well as resistance mechanisms to T and NK cell-based immunotherapy in HNSCC. The present review also provides an overview of the pre- and clinical early trials (I/II phase) and phase-III clinical trials published in this arena, which highlight the unprecedented effectiveness and limitations of immunotherapy in HNSCC, and the emerging issues facing the field of HNSCC immuno-oncology. [ABSTRACT FROM AUTHOR]

A craniopharyngioma (CP) is a rare epithelial tumor of the sellar and parasellar region. CPs are difficult to treat due to their anatomical proximity to critical nervous structures, which limits the ability of the surgeon to completely resect the lesion, exposing patients to a high risk of recurrence. The treatment of craniopharyngiomas is primarily surgery and radiotherapy. So far, neither a cell line nor an animal model has been established, and thus data on other treatment options, such as chemotherapy and immunotherapy, are limited. Here, the expression profile of the pan-cancer antigen B7-H3 in various cancer types including CP was examined by immunohistochemistry. An in vitro organoid model was established by using fresh tissue biospecimens of CP. Based on the organoid model, we evaluated the antitumor efficacy of B7-H3-targeted immunotherapy on CP. As a result, the highest expression of B7-H3 was observed in CP tissues across various cancer types. Although B7-H3-targeted chimeric antigen-receptor T cells show obvious tumor-killing effects in the traditional 2D cell culture model, limited antitumor effects were observed in the 3D organoid model. The B7-H3-targeted antibody-DM1 conjugate exhibited a potent tumor suppression function both in 2D and 3D models. In conclusion, for the first time, we established an organoid model for CP and our results support that B7-H3 might serve as a promising target for antibody-drug conjugate therapy against craniopharyngioma. [ABSTRACT FROM AUTHOR]

Simple Summary: We present the first mathematical model to describe the multiphasic dynamical treatment response in CAR-T cell kinetics through the differentiation of functional (distributed and effector), memory, and exhausted phenotypes, integrated with the dynamics of cancer cells. The CAR-T cell kinetics are evaluated for various hematological cancers and therapy outcomes, providing insights into promising parameters for long-term therapy investigation. Chimeric Antigen Receptor (CAR)-T cell immunotherapy revolutionized cancer treatment and consists of the genetic modification of T lymphocytes with a CAR gene, aiming to increase their ability to recognize and kill antigen-specific tumor cells. The dynamics of CAR-T cell responses in patients present multiphasic kinetics with distribution, expansion, contraction, and persistence phases. The characteristics and duration of each phase depend on the tumor type, the infused product, and patient-specific characteristics. We present a mathematical model that describes the multiphasic CAR-T cell dynamics resulting from the interplay between CAR-T and tumor cells, considering patient and product heterogeneities. The CAR-T cell population is divided into functional (distributed and effector), memory, and exhausted CAR-T cell phenotypes. The model is able to describe the diversity of CAR-T cell dynamical behaviors in different patients and hematological cancers as well as their therapy outcomes. Our results indicate that the joint assessment of the area under the concentration-time curve in the first 28 days and the corresponding fraction of non-exhausted CAR-T cells may be considered a potential marker to classify therapy responses. Overall, the analysis of different CAR-T cell phenotypes can be a key aspect for a better understanding of the whole CAR-T cell dynamics. [ABSTRACT FROM AUTHOR]

Simple Summary: Clear cell renal cell carcinoma (ccRCC) is a highly immunogenic tumor, with highly heterogeneous responses to immune checkpoint inhibition therapy. The role of immune cells infiltrating distant metastases and their impact on prognosis and response to immunotherapy are still unclear. To elucidate the prognostic value of immune cell subtypes, we analyzed the immune cell infiltrate in ccRCC primary tumors and paired distant metastases. We hypothesized that specific subtypes of immune cells may be involved in the control of metastases and may have an impact on the prognosis of ccRCC. Clear cell renal cell carcinoma (ccRCC) is a highly immunogenic tumor with variable responses to immune checkpoint therapy. The significance of the immune cell infiltrate in distant metastases, their association with the immune infiltrate in the primary tumors and their impact on prognosis are poorly described. We hypothesized that specific subtypes of immune cells may be involved in the control of metastases and may have an impact on the prognosis of ccRCC. We analyzed the immune microenvironment in ccRCC primary tumors with distant metastases, paired distant metastases and non-metastasized ccRCC (n = 25 each group) by immunohistochemistry. Confirmatory analyses for CD8+ and CD103+ cells were performed in a large ccRCC cohort (n = 241) using a TCGA-KIRC data set (ITGAE/CD103). High immune cell infiltration in primary ccRCC tumors was significantly correlated with the development of distant tumor metastasis (p < 0.05). A high density of CD103+ cells in ccRCC was more frequent in poorly differentiated tumors (p < 0.001). ccRCCs showed high levels of ITGAE/CD103 compared with adjacent non-neoplastic tissue. A higher density of CD103+ cells and a higher ITGAE/CD103 expression were significantly correlated with poor overall survival in ccRCC (log rank p < 0.05). Our results show a major prognostic value of the immune pattern, in particular CD103+ cell infiltration in ccRCC, and highlight the importance of the tumor immune microenvironment. [ABSTRACT FROM AUTHOR]

Imaging of CD8 receptors on T-cells by positron emission tomography (PET) has been considered a promising strategy for monitoring the treatment response to immunotherapy. In this study, a trial of imaging CD8 with our newly developed sequential multiple-agent receptor targeting (SMART) technology was conducted. Mice bearing a subcutaneous colorectal CT26 tumor received three times different immunotherapy treatments (PD1 or CTLA4 or combined). On either day 7 or day 14 after the first time treatment, the PET imaging study was performed with sequentially administered TCO-modified anti-CD8 antibody and 64Cu-labeled MeTz-NOTA-RGD. However, no positive response was detected, probably due to (1) inappropriate selection of biomarkers for the SMART strategy, (2) limited TCO modification on the anti-CD8 antibody, and (3) inadequate response of the CT26 tumor to the selected immunotherapies. Therefore, the potential of applying SMART in imaging CD8 was not demonstrated in this study, and further optimization will be necessary before it can be applied in imaging CD8. [ABSTRACT FROM AUTHOR]

Immunotherapy with checkpoint inhibitors revolutionized melanoma treatment in both the adjuvant and metastatic setting, yet not all metastatic patients respond, and metastatic disease still often recurs among immunotherapy-treated patients with locally advanced disease. TNFSF4 is a co-stimulatory checkpoint protein expressed by several types of immune and non-immune cells, and was shown in the past to enhance the anti-neoplastic activity of T cells. Here, we assessed its expression in melanoma and its association with outcome in locally advanced and metastatic disease. We used publicly available data from The Cancer Genome Atlas (TCGA) and the Cancer Cell Line Encyclopedia (CCLE), and RNA sequencing data from anti-PD1-treated patients at Sheba medical center. TNFSF4 mRNA is expressed in melanoma cell lines and melanoma samples, including those with low lymphocytic infiltrates, and is not associated with the ulceration status of the primary tumor. Low expression of TNFSF4 mRNA is associated with worse prognosis in all melanoma patients and in the cohorts of stage III and stage IIIc–IV patients. Low expression of TNFSF4 mRNAs is also associated with worse prognosis in the subgroup of patients with low lymphocytic infiltrates, suggesting that tumoral TNFSF4 is associated with outcome. TNFSF4 expression was not correlated with the expression of other known checkpoint mRNAs. Last, metastatic patients with TNFSF4 mRNA expression within the lowest quartile have significantly worse outcome on anti-PD1 treatment, and a significantly lower response rate to these agents. Our current work points to TNFSF4 expression in melanoma as a potential determinant of prognosis, and warrants further translational and clinical research. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the expression of CD1d and the susceptibility to invariant natural killer T (iNKT) cells in gastric cancer.Methods: The expression of CD1d was examined in gastric cancer. The in vitro and in vivo cytotoxic activities of iNKT cells were evaluated against gastric cancer cell lines.Results: CD1d was expressed in gastric cancer cell lines and primary tumors. iNKT cells have potent in vivo and in vitro anti-tumor activities against CD1d-positve gastric cancer in the presence of α-galactosylceramide. Cisplatin could upregulate CD1d expression in gastric cancer cells and make them more vulnerable to iNKT cell-mediated cytotoxicity.Conclusion: These results justified clinical translation of this iNKT cell-based therapeutics, either used alone or combined with chemotherapy, for the treatment of patients with gastric cancer. [ABSTRACT FROM AUTHOR]

Background: Dendritic cells (DCs) are unique antigen presenting cells (APC) which play a pivotal role in immunotherapy and induction of an effective immune response against tumors. In the present study, 80% ethanol extract of Phyllanthus amarus was used to generate tumor lysate (TLY) derived from HCT 116 and MCF-7 cancer cell lines via induction of apoptosis. Monocyte-derived DCs were generated ex vivo from the adherent population of peripheral blood mononuclear cells (PBMCs). The generated TLY were used to impulse DCs to investigate its effect on their cellular immune functions including antigen presentation capacity, phagocytic activity, chemotaxis capacity, T-cell proliferation and cytokines release. Methods: The effect of P. amarus -generated TLY on DCs maturation was evaluated by determination of MHC class I, II and CD 11c expression as well as the co-stimulatory molecules CD 83 and 86 by using flow cytometry. The phagocytic capacity of TLY-pulsed DCs was investigated through FITC-dextran uptake by using flow cytometry. The effect on the cytokines release including IL-12, IL-6 and IL-10 was elucidated by using ELISA. The migration capacity and T cell proliferation activity of pulsed DCs were measured. The relative gene expression levels of cytokines were determined by using qRT-PCR. The major constituents of P. amarus extract were qualitatively and quantitatively analyzed by using validated reversed-phase high performance liquid chromatography (HPLC) methods. Results: P. amarus -generated TLY significantly up-regulated the expression levels of MHC class I, CD 11 c, CD 83 and 86 in pulsed DCs. The release of interleukin IL-12 and IL-6 was enhanced by TLY-DCs at a ratio of 1 DC: 3 tumor apoptotic bodies (APO), however, the release of IL-10 was suppressed. The migration ability as well as allogeneic T-cell proliferation activities of loaded DCs were significantly enhanced, but their phagocytic capacity was highly attenuated. The gene expression profiles for IL-12 and IL-6 of DCs showed increase in their mRNA gene expression in TLY pulsed DCs versus unloaded and LPS-treated only DCs. Conclusion: The effect of P. amarus -generated TLY on the immune effector mechanisms of DCs verified its potential to induce an in vitro anti-tumor immune response against the recognized tumor antigen. [ABSTRACT FROM AUTHOR]

A growing understanding of the molecular interactions between immune effector cells and target tumor cells, coupled with refined gene therapy approaches, are giving rise to novel cancer immunotherapeutics with remarkable efficacy in the clinic against both solid and liquid tumors. While immunotherapy holds tremendous promise for treatment of certain cancers, significant challenges remain in the clinical translation to many other types of cancers and also in minimizing adverse effects. Therefore, there is an urgent need for functional potency assays, in vitro and in vivo, that could model the complex interaction of immune cells with tumor cells and can be used to rapidly test the efficacy of different immunotherapy approaches, whether it is small molecule, biologics, cell therapies or combinations thereof. Herein we report the development of an xCELLigence real-time cytolytic in vitro potency assay that uses cellular impedance to continuously monitor the viability of target tumor cells while they are being subjected to different types of treatments. Specialized microtiter plates containing integrated gold microelectrodes enable the number, size, and surface attachment strength of adherent target tumor cells to be selectively monitored within a heterogeneous mixture that includes effector cells, antibodies, small molecules, etc. Through surface-tethering approach, the killing of liquid cancers can also be monitored. Using NK92 effector cells as example, results from RTCA potency assay are very well correlated with end point data from image-based assays as well as flow cytometry. Several effector cells, i.e., PBMC, NK, CAR-T were tested and validated as well as biological molecules such as Bi-specific T cell Engagers (BiTEs) targeting the EpCAM protein expressed on tumor cells and blocking antibodies against the immune checkpoint inhibitor PD-1. Using the specifically designed xCELLigence immunotherapy software, quantitative parameters such as KT50 (the amount of time it takes to kill 50% of the target tumor cells) and % cytolysis are calculated and used for comparing the relative efficacy of different reagents. In summary, our results demonstrate the xCELLigence platform to be well suited for potency assays, providing quantitative assessment with high reproducibility and a greatly simplified work flow. [ABSTRACT FROM AUTHOR]

Background: Recently, immunotherapy with anti-PD-1 antibodies has shown clinical benefit in recurrent Small Cell Lung Cancer (SCLC). Since anti-PD-1 re-activates anti-tumor Cytotoxic T Lymphocyte (CTL) responses, it is crucial to understand the mechanisms regulating HLA class I, and PD-L1 expression in HLA-negative SCLC. Here we addressed the role of IL-27, a cytokine related to both IL-6 and IL-12 families. Methods: The human SCLC cell lines NCI-N592, -H69, -H146, -H446 and -H82 were treated in vitro with different cytokines (IL-27, IFN-γ, IL-6 or a soluble IL-6R/IL-6 chimera [sIL-6R/IL-6]) at different time points and analyzed for tyrosine-phosphorylated STAT proteins by Western blot, for surface molecule expression by immunofluorescence and FACS analyses or for specific mRNA expression by QRT-PCR. Relative quantification of mRNAs was calculated by the ΔΔCT method. The Student’s T test was used for the statistical analysis of experimental replicates. Results: IL-27 triggered STAT1/3 phosphorylation and up-regulated the expression of surface HLA class I antigen and of TAP1 and TAP2 mRNA in four out of five SCLC cell lines tested. The IL-27-resistant NCI-H146 cells showed upregulation of HLA class I by IFN-γ. IFN-γ also induced expression of PD-L1 in SCLC cells, while IL-27 was less potent in this respect. IL-27 failed to activate STAT1/3 phosphorylation in NCI-H146 cells, which display a low expression of the IL-27RA and GP130 receptor chains. As GP130 is shared in IL-27R and IL-6R complexes, we assessed its functionality in response to sIL-6R/IL-6. sIL-6R/IL-6 failed to trigger STAT1/3 signaling in NCI-H146 cells, suggesting low GP130 expression or uncoupling from signal transduction. Although both sIL-6R/IL-6 and IL-27 triggered STAT1/ 3 phosphorylation, sIL-6R/IL-6 failed to up-regulate HLA class I expression, in relationship to the weak activation of STAT1. Finally sIL-6R/IL-6 limited IL-27-effects, particularly in NCI-H69 cells, in a SOCS3-independent manner, but did not modify IFN-γ induced HLA class I up-regulation. Conclusions: In conclusion, IL-27 is a potentially interesting cytokine for restoring HLA class I expression for SCLC combined immunotherapy purposes. However, the concomitant activation of the IL-6 pathway may limit the IL-27 effect on HLA class I induction but did not significantly alter the responsiveness to IFN-γ. [ABSTRACT FROM AUTHOR]

In cancer patients, the immune system is often altered with an excess of inhibitory factors, such as immunosuppressive cytokines, produced by regulatory T cells (Treg) or myeloid-derived suppressor cells (MDSC). The manipulation of the immune system has emerged as one of new promising therapies for cancer treatment, and also represents an attractive strategy to control prostate cancer (PCa). Therapeutic cancer vaccines and immune checkpoint inhibitors have been the most investigated in clinical trials. Many trials are ongoing to define the effects of immune therapy with established treatments: androgen deprivation therapy (ADT) and chemotherapy (CT) or radiotherapy (RT). This article discusses some of these approaches in the context of future treatments for PCa. [ABSTRACT FROM AUTHOR]

We aimed to assess the status of naturally occurring CD4+ and CD8+ T cell responses to a tumour associated antigen, Mesothelin, in patients with pancreatic carcinoma and study the effects of elevated IL-10 on Mesothelin-specific T cell responses. For that sake, short term T cell lines were generated from PBMCs of 16 healthy controls, 15 patients with benign pancreatic diseases and 25 patients with pancreatic carcinoma and Mesothelin-specific CD4+ and CD8+ T cell responses were analysed using intracellular cytokine assays for IFN-γ. Plasma levels of IL-10 and Mesothelin were measured using cytometric bead array and ELISA assay, respectively. The blocking assays were performed to assess the effects of IL-10 on Mesothelin-specific T cell responses. Here, we demonstrate that the plasma levels of Mesothelin and IL-10 are significantly increased in patients with pancreatic carcinoma. Additionally, we found that (a) Mesothelin-specific T cell responses are significantly expanded in cancer patients (p = 0.0053), (b) the multifunctional CD4+ T cell response is directed toward a broad repertoire of epitopes within the Mesothelin protein. (c) Mesothelin-specific CD4+ T cell response is directly inhibited by elevated IL-10 in cancer patients. These data provides evidence for the use of Mesothelin as an immunogen for tumour-specific T cell response. [ABSTRACT FROM AUTHOR]

In retroviral vector-mediated gene transfer, transduction efficiency can be hampered by inhibitory molecules derived from the culture fluid of virus producer cell lines. To remove these inhibitory molecules to enable better gene transduction, we had previously developed a transduction method using a fibronectin fragment-coated vessel (i.e., the RetroNectin-bound virus transduction method). In the present study, we developed a method that combined RetroNectin-bound virus transduction with low-temperature shaking and applied this method in manufacturing autologous retroviral-engineered T cells for adoptive transfer gene therapy in a large-scale closed system. Retroviral vector was preloaded into a RetroNectin-coated bag and incubated at 4°C for 16 h on a reciprocating shaker at 50 rounds per minute. After the supernatant was removed, activated T cells were added to the bag. The bag transduction method has the advantage of increasing transduction efficiency, as simply flipping over the bag during gene transduction facilitates more efficient utilization of the retroviral vector adsorbed on the top and bottom surfaces of the bag. Finally, we performed validation runs of endoribonuclease MazF-modified CD4+ T cell manufacturing for HIV-1 gene therapy and T cell receptor-modified T cell manufacturing for MAGE-A4 antigen-expressing cancer gene therapy and achieved over 200-fold (≥1010) and 100-fold (≥5×109) expansion, respectively. In conclusion, we demonstrated that the large-scale closed transduction system is highly efficient for retroviral vector-based T cell manufacturing for adoptive transfer gene therapy, and this technology is expected to be amenable to automation and improve current clinical gene therapy protocols. [ABSTRACT FROM AUTHOR]

Vδ2neg γδ T cells, of which Vδ1+ γδ T cells are by far the largest subset, are important effectors against CMV infection. Malignant gliomas often contain CMV genetic material and proteins, and evidence exists that CMV infection may be associated with initiation and/or progression of glioblastoma multiforme (GBM). We sought to determine if Vδ1+ γδ T cells were cytotoxic to GBM and the extent to which their cytotoxicity was CMV dependent. We examined the cytotoxic effect of ex vivo expanded/activated Vδ1+ γδ T cells from healthy CMV seropositive and CMV seronegative donors on unmanipulated and CMV-infected established GBM cell lines and cell lines developed from short- term culture of primary tumors. Expanded/activated Vδ1+ T cells killed CMV-negative U251, U87, and U373 GBM cell lines and two primary tumor explants regardless of the serologic status of the donor. Experimental CMV infection did not increase Vδ1+ T cell - mediated cytotoxicity and in some cases the cell lines were more resistant to lysis when infected with CMV. Flow cytometry analysis of CMV-infected cell lines revealed down-regulation of the NKG2D ligands ULBP-2, and ULBP-3 as well as MICA/B in CMV-infected cells. These studies show that ex vivo expanded/activated Vδ1+ γδ T cells readily recognize and kill established GBM cell lines and primary tumor-derived GBM cells regardless of whether CMV infection is present, however, CMV may enhance the resistance GBM cell lines to innate recognition possibly contributing to the poor immunogenicity of GBM. [ABSTRACT FROM AUTHOR]

Classical approaches to immunotherapy that show promise in some malignancies have generally been disappointing when applied to high-grade brain tumors such as glioblastoma multiforme (GBM). We recently showed that ex vivo expanded/activated γδ T cells recognize NKG2D ligands expressed on malignant glioma and are cytotoxic to glioma cell lines and primary GBM explants. In addition, γδ T cells extend survival and slow tumor progression when administered to immunodeficient mice with intracranial human glioma xenografts. We now show that temozolomide (TMZ), a principal chemotherapeutic agent used to treat GBM, increases the expression of stress-associated NKG2D ligands on TMZ-resistant glioma cells, potentially rendering them vulnerable to γδ T cell recognition and lysis. TMZ is also highly toxic to γδ T cells, however, and to overcome this cytotoxic effect γδ T cells were genetically modified using a lentiviral vector encoding the DNA repair enzyme O(6)-alkylguanine DNA alkyltransferase (AGT) from the O(6)-methylguanine methyltransferase (MGMT) cDNA, which confers resistance to TMZ. Genetic modification of γδ T cells did not alter their phenotype or their cytotoxicity against GBM target cells. Importantly, gene modified γδ T cells showed greater cytotoxicity to two TMZ resistant GBM cell lines, U373TMZ-R and SNB-19TMZ-R cells, in the presence of TMZ than unmodified cells, suggesting that TMZ exposed more receptors for γδ T cell-targeted lysis. Therefore, TMZ resistant cd T cells can be generated without impairing their anti-tumor functions in the presence of high concentrations of TMZ. These results provide a mechanistic basis for combining chemotherapy and γδ T cell-based drug resistant cellular immunotherapy to treat GBM. [ABSTRACT FROM AUTHOR]

Neuroblastoma (NB), the most common solid extracranial cancer of childhood, displays a remarkable low expression of Major Histocompatibility Complex class I (MHC-I) and Antigen Processing Machinery (APM) molecules, including Endoplasmic Reticulum (ER) Aminopeptidases, and poorly presents tumor antigens to Cytotoxic T Lymphocytes (CTL). We have previously shown that this is due to low expression of the transcription factor NF-kB p65. Herein, we show that not only NF-kB p6, but also the Interferon Regulatory Factor 1 (IRF1) and certain APM components are low in a subset of NB cell lines with aggressive features. Whereas single transfection with either IRF, or NF-kB p65 is ineffective, co-transfection results in strong synergy and substantial reversion of the MHC-I/APM-low phenotype in all NB cell lines tested. Accordingly, linked immunohistochemistry expression patterns between nuclear IRF1 and p65 on the one hand, and MHC-I on the other hand, were observed in vivo. Absence and presence of the three molecules neatly segregated between high-grade and low- grade NB, respectively. Finally, APM reconstitution by double IRF1/p65 transfection rendered a NB cell line susceptible to killing by anti MAGE-A3 CTLs, lytic efficiency comparable to those seen upon IFN-γ treatment. This is the first demonstration that a complex immune escape phenotype can be rescued by reconstitution of a limited number of master regulatory genes. These findings provide molecular insight into defective MHC-I expression in NB cells and provide the rational for T cell-based immunotherapy in NB variants refractory to conventional therapy. [ABSTRACT FROM AUTHOR]

Background: Chondrosarcoma has no proven systemic option in the metastatic setting. The development of a non-crossresistant strategy, such as cellular immunotherapy using antigen-specific T cells would be highly desirable. NY-ESO-1 and PRAME are members of the Cancer Testis Antigen (CTA) family that have been identified as promising targets for T cell therapy. LAGE-1 is a cancer testis antigen 90% homologous to NY-ESO-1, sharing the 157-165 A*0201 NY-ESO-1 epitope with its transcript variant, LAGE-1s. A number of CTA's have been induced using 5-Aza-2-Deoxycitabine (5-Aza-dC) in other cancers. We sought to evaluate the feasibility of targeting chondrosarcoma tumors using NY-ESO-1/LAGE-1s and PRAME specific T cells using 5-Aza-dC to induce antigen expression. Methods: We used 11 flash frozen tumors from the University of Washington tumor bank to test for the expression of NYESO- 1, PRAME, LAGE-1s and LAGE-1L in chondrosarcoma tumors. Using four chondrosarcoma cell lines we tested the expression of these CTA's with and without 5-Aza-dC treatments. Finally, using NY-ESO-1/LAGE-1s and PRAME specific effectors that we generated from sarcoma patients, we evaluated the ability of these T cells to lyse A*0201 expressing chondrosarcoma cell lines in vitro both with and without 5-Aza-dC treatment. Results: A minority (36%) of chondrosarcoma tumors expressed either NY-ESO-1 or LAGE-1s at >10% of our reference value and none expressed PRAME at that level. However, in all four of the chondrosarcoma cell lines tested, NY-ESO-1 and PRAME expression could be induced following treatment with 5-Aza-dC including in cell lines where expression was absent or barely detectable. Furthermore, NY-ESO-1/LAGE-1s and PRAME specific CD8+ effector T cells were able to specifically recognize and lyse A*0201 expressing chondrosarcoma cell lines following 5-Aza-dC treatment. Conclusion: These data suggest that adoptive immunotherapy in combination with 5-Aza-dC may be a potential strategy to treat unresectable or metastatic chondrosarcoma patients where no proven systemic therapies exist. [ABSTRACT FROM AUTHOR]

CD3(+)CD56(-), CD4 and CD8 double negative T (DNT) cells comprise 1-3% of peripheral blood (PB) mononuclear cells. Their role in tumor immunity remains largely unknown due to their limited numbers and lack of effective methods to expand them. Here we developed a novel protocol by which DNT cells can be expanded ex vivo to therapeutic levels in 2 weeks from 13 of 16 acute myeloid leukemia (AML) patients during chemotherapy-induced complete remission. The expanded DNT cells expressed similar or higher levels of interferon-γ and tumor necrosis factor-α and Granzyme B as that seen in bulk activated CD8T cells from the same patient but significantly higher levels of perforin. The expanded DNT cells could effectively kill both allogeneic and autologous primary CD34(+) leukemic blasts isolated from PB of AML patients in a perforin-dependant manner. These results demonstrate, for the first time, that DNT cells from AML patients can be expanded ex vivo even after intensive chemotherapy, and are effective at killing both allogeneic and autologous primary leukemic blasts. These findings warrant studies further exploring the potential of DNT cells as a novel adjuvant immunotherapy to decrease the risk of relapse in patients with AML and, perhaps, other cancers. [ABSTRACT FROM AUTHOR]

Background: The development of a successful immunotherapy is hampered by an ineffective T-cell repertoire against tumour antigens and the inability of the patient's immune system to overcome tolerance-inducing mechanisms. Here, we test the specific recognition and lytical potential of allo-restricted CD8(+) T cells against Ewing tumour (ET) associated antigens Enhancer of Zeste, Drosophila Homolog 2 (EZH2), and Chondromodulin-I (CHM1) identified through previous microarray analysis.Methods: Following repetitive CHM1(319) (VIMPCSWWV) and EZH2(666) (YMCSFLFNL) peptide-driven stimulations with HLA-A 0201(+) dendritic cells (DC), allo-restricted HLA-A 0201(-) CD8(+) T cells were stained with HLA-A 0201/peptide multimers, sorted and expanded by limiting dilution.Results: Expanded T cells specifically recognised peptide-pulsed target cells or antigen-transfected cells in the context of HLA-A 0201 and killed HLA-A 0201(+) ET lines expressing the antigen while HLA-A 0201(-) ET lines were not affected. Furthermore, adoptively transferred T cells caused significant ET growth delay in Rag2(-/-)γ(C)(-/-) mice. Within this context, we identified the CHM1(319) peptide as a new candidate target antigen for ET immunotherapy.Conclusion: These results clearly identify the ET-derived antigens, EZH2(666) and CHM1(319), as suitable targets for protective allo-restricted human CD8(+) T-cell responses against non-immunogenic ET and may benefit new therapeutic strategies in ET patients treated with allogeneic stem cell transplantation. [ABSTRACT FROM AUTHOR]

Simple Summary: c-Met is known to be overexpressed in gastric cancers. Here, we developed anti-c-Met CAR T cell and measured its anti-tumor efficacy in vitro and in vivo. Our anti c-Met CAR T cells have shown selective killing of c-Met overexpressed gastric cancer cells. Based on our results, we suggest that anti-c-Met CAR T cell therapy could be effective for gastric cancer patients. Chimeric antigen receptor (CAR) technology has been highlighted in recent years as a new therapeutic approach for cancer treatment. Although the impressive efficacy of CAR-based T cell adoptive immunotherapy has been observed in hematologic cancers, limited effect has been reported on solid tumors. Approximately 20% of gastric cancer (GC) patients exhibit a high expression of c-Met. We have generated an anti c-Met CAR construct that is composed of a single-chain variable fragment (scFv) of c-Met antibody and signaling domains consisting of CD28 and CD3ζ. To test the CAR construct, we used two cell lines: the Jurkat and KHYG-1 cell lines. These are convenient cell lines, compared to primary T cells, to culture and to test CAR constructs. We transduced CAR constructs into Jurkat cells by electroporation. c-Met CAR Jurkat cells secreted interleukin-2 (IL-2) only when incubated with c-Met positive GC cells. To confirm the lytic function of CAR, the CAR construct was transduced into KHYG-1, a NK/T cell line, using lentiviral particles. c-Met CAR KHYG-1 showed cytotoxic effect on c-Met positive GC cells, while c-Met negative GC cell lines were not eradicated by c-Met CAR KHYG-1. Based on these data, we created c-Met CAR T cells from primary T cells, which showed high IL-2 and IFN-γ secretion when incubated with the c-Met positive cancer cell line. In an in vivo xenograft assay with NSG bearing MKN-45, a c-Met positive GC cell line, c-Met CAR T cells effectively inhibited the tumor growth of MKN-45. Our results show that the c-Met CAR T cell therapy can be effective on GC. [ABSTRACT FROM AUTHOR]

Simple Summary: This review focuses on the effects that a class of drugs, PI3Kδ inhibitors, used for the treatment of patients with lymphoma can have not on the neoplastic cells but on the normal cells and how this effect can modulate the immune response and potentially contribute to the anti-tumor response. The development of small molecules able to block specific or multiple isoforms of phosphoinositide 3-kinases (PI3K) has already been an active field of research for many years in the cancer field. PI3Kδ inhibitors are among the targeted agents most extensively studied for the treatment of lymphoma patients and PI3Kδ inhibitors are already approved by regulatory agencies. More recently, it became clear that the anti-tumor activity of PI3K inhibitors might not be due only to a direct effect on the cancer cells but it can also be mediated via inhibition of the kinases in non-neoplastic cells present in the tumor microenvironment. T-cells represent an important component of the tumor microenvironment and they comprise different subpopulations that can have both anti- and pro-tumor effects. In this review article, we discuss the effects that PI3Kδ inhibitors exert on the immune system with a particular focus on the T-cell compartment. [ABSTRACT FROM AUTHOR]

Simple Summary: Triple-negative breast cancer (TNBC) is the most refractory subtype of breast cancer. Immune checkpoint inhibitor (ICI) therapy has made progress in TNBC treatment. PD-L1 expression is a useful biomarker of ICI therapy efficacy. However, tumor-immune microenvironment (TIME) factors, such as immune cell compositions and tumor-infiltrating lymphocyte (TIL) status, also influence tumor immunity. Therefore, it is necessary to seek biomarkers that are associated with multiple aspects of TIME in TNBC. In this study, we developed an immune-related gene prognostic index (IRGPI) with a substantial prognostic value for TNBC. Moreover, the results from multiple cohorts reproducibly demonstrate that IRGPI is significantly associated with immune cell compositions, the exclusion and dysfunction of TILs, as well as PD-1 and PD-L1 expression in TIME. Therefore, IRGPI is a promising biomarker closely related to patient survival and TIME of TNBC and may have a potential effect on the immunotherapy strategy of TNBC. Tumor-immune cell compositions and immune checkpoints comprehensively affect TNBC outcomes. With the significantly improved survival rate of TNBC patients treated with ICI therapies, a biomarker integrating multiple aspects of TIME may have prognostic value for improving the efficacy of ICI therapy. Immune-related hub genes were identified with weighted gene co-expression network analysis and differential gene expression assay using The Cancer Genome Atlas TNBC data set (n = 115). IRGPI was constructed with Cox regression analysis. Immune cell compositions and TIL status were analyzed with CIBERSORT and TIDE. The discovery was validated with the Molecular Taxonomy of Breast Cancer International Consortium data set (n = 196) and a patient cohort from our hospital. Tumor expression or serum concentrations of CCL5, CCL25, or PD-L1 were determined with immunohistochemistry or ELISA. The constructed IRGPI was composed of CCL5 and CCL25 genes and was negatively associated with the patient's survival. IRGPI also predicts the compositions of M0 and M2 macrophages, memory B cells, CD8+ T cells, activated memory CD4 T cells, and the exclusion and dysfunction of TILs, as well as PD-1 and PD-L1 expression of TNBC. IRGPI is a promising biomarker for predicting the prognosis and multiple immune characteristics of TNBC. [ABSTRACT FROM AUTHOR]

Background CD40-activated B lymphocytes have been used successfully as potent APC for the induction of T-cell responses. However, the 3T3-CD40L cell line, regularly used for engagement of CD40 on the B-cell surface, is a potential source of xenoantigens. This may affect the specificity of T cells stimulated with CD40-activated B cells, especially when generation of T-cell lines specific for endogenously processed Ag is desired. Methods To develop a system that allows efficient expansion of B cells in the absence of sources of xenoantigens, we created a human 293-CD40L-sCD40L cell line that produces soluble CD40L and expresses CD40L on the cell surface. B cells from patients with hematologic malignancies were expanded on the 293-CD40L-sCD40L cells and used for stimulation of either naive or in vivo primed donor T cells in three HLA-identical patient-donor combinations. Results The 293-CD40L-sCD40L cell line was able to stimulate B-cell growth with an efficiency superior to that of the commonly used 3T3-CD40L cell line. In all cases T-cell lines and, subsequently, T-cell clones were generated that showed reactivity against patient and not donor B cells, suggesting their specificity for minor histocompatibility antigens (mHAg). Discussion B cells activated with GMP grade 293-CD40L-sCD40L can be used in a variety of applications. In particular, they may be suitable for ex vivo stimulation of T cells prior to donor lymphocyte infusion (DLI), which may enhance its graft versus leukemia (GvL) effect. [ABSTRACT FROM AUTHOR]

Simple Summary: Bispecific antibodies are a very effective immunotherapy against different types of cancer since they activate T cells in the presence of tumor cells. However, they can cause severe side effects, such as a systemic inflammation called cytokine release syndrome. We aimed to clarify an important mechanism that causes cytokine release syndrome. In cocultures of T cells with endothelial cells or lymphoid cells, application of bispecific antibodies can induce T cell activation and cytokine release in the absence of tumor cells. By blocking the adhesion molecule CD18, this interaction is interrupted and the unwanted T cell activation is diminished. CD18 blockade, however, does not interfere with T cell activation when tumor cells are present. Therefore, CD18 blockade could prevent side effects of bispecific antibodies without decreasing the anti-tumor effect. T cell-recruiting bispecific antibodies (bsAbs) are successfully used for the treatment of cancer. However, effective treatment with bsAbs is so far hampered by severe side effects, i.e., potentially life-threatening cytokine release syndrome. Off-target T cell activation due to binding of bispecific CD3 antibodies to T cells in the absence of target cells may contribute to excessive cytokine release. We report here, in an in vitro setting, that off-target T cell activation is induced by bsAbs with high CD3 binding affinity and increased by endothelial- or lymphoid cells that act as stimulating bystander cells. Blocking antibodies directed against the adhesion molecules CD18/CD54 or CD2/CD58 markedly reduced this type of off-target T cell activation. CD18 blockade—in contrast to CD2—did not affect the therapeutic activity of various bsAbs. Since CD18 antibodies have been shown to be safely applicable in patients, blockade of this integrin holds promise as a potential target for the prevention of unwanted off-target T cell activation and allows the application of truly effective bsAb doses. [ABSTRACT FROM AUTHOR]

Simple Summary: Osteosarcoma (OS) is the most common bone tumor in the pediatric population, and long-term survival occurs in less than a third of the population with metastatic or recurrent tumors. Secreted frizzled-related protein 2 (SFRP2) promotes metastatic OS cell migration and tumor angiogenesis. This study aimed to assess the role of antagonizing SFRP2 with a humanized monoclonal antibody to SFRP2 (hSFRP2 mAb) in OS metastases in vivo and the role of SFRP2 in T-cells. Our results demonstrate that hSFRP2 mAb treatment inhibits metastases in two metastatic models of OS and can overcome resistance to a PD-1 monoclonal antibody. hSFRP2 mAb treatment restores T-cell proliferation and, in T-cells, inhibits NFATc3, CD38 and PD-1 expression. We conclude that SFRP2-targeted immunotherapy reduces the growth of metastatic osteosarcoma, not only through a direct antitumor and antiangiogenic effect but also by impacting the immune system. Secreted frizzled-related protein 2 (SFRP2) promotes the migration/invasion of metastatic osteosarcoma (OS) cells and tube formation by endothelial cells. However, its function on T-cells is unknown. We hypothesized that blocking SFRP2 with a humanized monoclonal antibody (hSFRP2 mAb) can restore immunity by reducing CD38 and PD-1 levels, ultimately overcoming resistance to PD-1 inhibitors. Treating two metastatic murine OS cell lines in vivo, RF420 and RF577, with hSFRP2 mAb alone led to a significant reduction in the number of lung metastases, compared to IgG1 control treatment. While PD-1 mAb alone had minimal effect, hSFRP2 mAb combination with PD-1 mAb had an additive antimetastatic effect. This effect was accompanied by lower SFRP2 levels in serum, lower CD38 levels in tumor-infiltrating lymphocytes and T-cells, and lower PD-1 levels in T-cells. In vitro data confirmed that SFRP2 promotes NFATc3, CD38 and PD-1 expression in T-cells, while hSFRP2 mAb treatment counteracts these effects and increases NAD+ levels. hSFRP2 mAb treatment further rescued the suppression of T-cell proliferation by tumor cells in a co-culture model. Finally, hSFRP2 mAb induced apoptosis in RF420 and RF577 OS cells but not in T-cells. Thus, hSFRP2 mAb therapy could potentially overcome PD-1 inhibitor resistance in metastatic osteosarcoma. [ABSTRACT FROM AUTHOR]

Simple Summary: Tumor-Associated Macrophages (TAMs) play an important role in the development of tumors, modulation of neoangiogenesis, immune suppression, and metastasis. High infiltration of macrophages in the tumor is also correlated with poor prognosis in several cancer types. Therefore, they became an attractive target for cancer immunotherapies. In this review, we describe the role of macrophages in tumorigenesis and summarize the most recent advances in the therapies targeting TAMs. Macrophages are critical mediators of tissue homeostasis and influence various aspects of immunity. Tumor-associated macrophages are one of the main cellular components of the tumor microenvironment. Depending on their activation status, macrophages can exert a dual influence on tumorigenesis by either antagonizing the cytotoxic activity of immune cells or, less frequently, by enhancing antitumor responses. In most situations, TAMs suppress T cell recruitment and function or regulate other aspects of tumor immunity. The importance of TAMs targeting in cancer therapy is derived from the strong association between the high infiltration of TAMs in the tumor tissue with poor patient prognosis. Several macrophage-targeting approaches in anticancer therapy are developed, including TAM depletion, inhibition of new TAM differentiation, or re-education of TAM activation for cancer cell phagocytosis. In this review, we will describe the role of TAMs in tumor development, including such aspects as protumorigenic inflammation, immune suppression, neoangiogenesis, and enhancement of tissue invasion and distant metastasis. Furthermore, we will discuss therapeutic approaches that aim to deplete TAMs or, on the contrary, re-educate TAMs for cancer cell phagocytosis and antitumor immunity. [ABSTRACT FROM AUTHOR]

Simple Summary: Both cancer cells and immune cells depend on specific metabolic programs for their survival and function. Depending on which metabolic changes occur, immune cells can either promote or suppress the antitumor immune response. This review summarizes the metabolic pathways that polarize innate immune cells for immune activation or suppression and describes the current clinical applications of these findings. Cancer cells possess specific metabolic requirements for their survival, proliferation, and progression. Within a shared microenvironment, immune cells depend on competing metabolic pathways for their development and effector function. As a result, local acidification, hypoxia, and nutrient depletion in the tumor microenvironment can alter the antitumor immune response and even promote resistance to immunotherapies such as immune checkpoint blockade and adoptive cell transfer. Although T cells are the primary effectors of the antitumor response, growing evidence demonstrates that innate immune cells are critical to successful tumor clearance. This review aims to summarize current research related to the innate immune system, metabolism, and cancer. We first discuss the specific metabolic requirements of innate immune cells for immune activation and suppression and conclude by highlighting ongoing clinical applications of these findings. [ABSTRACT FROM AUTHOR]

The failure of therapies directed at targets within cancer cells highlight the necessity for a paradigm change in cancer therapy. The attention of researchers has shifted towards the disruption of cancer cell interactions with the tumor microenvironment. A typical example of such a disruption is the immune checkpoint cancer therapy that disrupts interactions between the immune and the cancer cells. The interaction of cancer antigens with T cells occurs in the immunological synapses. This is characterized by several special features, i.e., the proximity of the immune cells and their target cells, strong intercellular adhesion, and secretion of signaling cytokines into the intercellular cleft. Earlier, we hypothesized that the cancer-associated fibroblasts interacting with cancer cells through a synapse-like adhesion might play an important role in cancer tumors. Studies of the interactions between cancer cells and cancer-associated fibroblasts showed that their clusterization on the membrane surface determined their strength and specificity. The hundreds of interacting pairs are involved in the binding that may indicate the formation of synapse-like structures. These interactions may be responsible for successful metastasis of cancer cells, and their identification and disruption may open new therapeutic possibilities. [ABSTRACT FROM AUTHOR]

Aminobisphosphonates, such as zoledronic acid (ZA), have shown potential in the treatment of different malignancies, including colorectal carcinoma (CRC). Yet, their clinical exploitation is limited by their high bone affinity and modest bioavailability. Here, ZA is encapsulated into the aqueous core of spherical polymeric nanoparticles (SPNs), whose size and architecture resemble that of biological vesicles. On Vδ2 T cells, derived from the peripheral blood of healthy donors and CRC patients, ZA-SPNs induce proliferation and trigger activation up to three orders of magnitude more efficiently than soluble ZA. These activated Vδ2 T cells kill CRC cells and tumor spheroids, and are able to migrate toward CRC cells in a microfluidic system. Notably, ZA-SPNs can also stimulate the proliferation of Vδ2 T cells from the tumor-infiltrating lymphocytes of CRC patients and boost their cytotoxic activity against patients' autologous tumor organoids. These data represent a first step toward the use of nanoformulated ZA for immunotherapy in CRC patients. [ABSTRACT FROM AUTHOR]

CAR-T (chimeric antigen receptor T cells) immunotherapy is effective in many hematological cancers; however, efficacy in solid tumors is disappointing. Doublecortin-like kinase 1 (DCLK1) labels tumor stem cells (TSCs) in genetic mouse models of colorectal cancer (CRC). Here, we describe a novel CAR-T targeting DCLK1 (CBT-511; with our proprietary DCLK1 single-chain antibody variable fragment) as a treatment strategy to eradicate CRC TSCs. The cell surface expression of DCLK1 and cytotoxicity of CBT-511 were assessed in CRC cells (HT29, HCT116, and LoVo). LoVo-derived tumor xenografts in NOD Scid gamma (NSG™) mice were treated with CBT-511 or mock CAR-T cells. Adherent CRC cells express surface DCLK1 (two-dimensional, 2D). A 4.5-fold increase in surface DCLK1 was observed when HT29 cells were grown as spheroids (three-dimensional, 3D). CBT-511 induced cytotoxicity (2D; p < 0.0001), and increased Interferon gamma (IFN-γ) release in CRC cells (2D) compared to mock CAR-T (p < 0.0001). Moreover, an even greater increase in IFN-γ release was observed when cells were grown in 3D. CBT-511 reduced tumor growth by approximately 50 percent compared to mock CAR-T. These data suggest that CRC cells with increased clonogenic capacity express increased surface DCLK1. A DCLK1-targeted CAR-T can induce cytotoxicity in vitro and inhibit xenograft growth in vivo. [ABSTRACT FROM AUTHOR]

The life span of dendritic cells (DCs) can become short following induced activation, which is associated with metabolic transition due to the regulation of mechanistic target of rapamycin (mTOR). The purpose of this study was to investigate the potential of inhibiting mTOR to modulate DC functions for elevating the anti-tumor effects of DNA vaccines. Therefore, the influences of various inhibitors of mTOR (mTORi) on the expressions of DC maturation markers, the abilities of antigen presenting and processing of BMM-derived DCs and the tumor killing effects of E7-specific CD8+ T lymphocytes activated by BMM-derived DCs were in vitro examined. The anti-tumor effects of connective tissue growth factor (CTGF)/E7 DNA vaccine and/or mTORi were also in vivo analyzed. In our study, suppressive effects of mTORi on the DC maturation markers expressed on BMMCs could be reversed. The mTORi-treated mature BMM-derived DCs tended to be non-apoptotic. These mTORi-treated BMM-derived DCs could have better antigen presenting and processing abilities. The E7-specific cytotoxic CD8+ T lymphocytes could have more potent tumoricidal activity following activation of mTORi-treated BMM-derived DCs. For tumor-bearing mice, those treated with CTGF/E7 DNA vaccine and mTORi indeed can have higher percentages of mature DCs in the TME, better disease control and longer survivals. Consequently, application of mTORi can be a pharmacological approach for temporally increasing life span, antigen presenting and antigen processing of DCs to strengthen the therapeutic outcome of cancer immunotherapy. [ABSTRACT FROM AUTHOR]

Both EBV+ and MSI gastric cancers (GCs) have high lymphoid infiltration which is rare in MSS/EBV− cancers. PD-L1/PD-1 interaction leads to a down-regulated immune response and it is one of the most promising targets for gastric cancer immunotherapy. PD-L1/PD-1 and CD8 expression were immunohistochemically investigated in a series of 169 FFPE GCs, including 33 EBV+, 59 MSI and 77 MSS/EBV− cases. PD-L1 membrane immunoreactivity in more than 5% of tumor cells was present in 31/169 GCs and was associated with high levels of CD8 intraepithelial lymphocytes (TILs; p < 0.001). PD-L1+ cases were mainly poorly differentiated (71%), intestinal type (85%) and high lymphoid response (HLR; 90%) tumors. PD-L1 expression was only present in EBV⁺ (46%), MSI (24%) and rare MSS/EBV− (3%) GCs with high CD8+ TILs (p < 0.001). Despite being associated with a better prognosis both in the whole series (p < 0.05) and in the MSI subset, PD-L1 is not an independent prognostic factor. PD-L1 gene amplification was detected in 3/17 cases, including 2/7 EBV+ and 1/8 MSI GC. PD-1⁺ TILs were significantly higher in EBV⁺ than MSI and MSS/EBV− cases. PD-L1/PD-1 pathway is selectively activated in HLR GCs and could be considered an emerging therapeutic target, particularly for EBV and MSI GCs. [ABSTRACT FROM AUTHOR]