The Evolution of T-cell Therapies for Solid Malignancies

Infusion and delivery strategies to maximize the efficacy of CAR-T cell immunotherapy for cancers

Chimeric antigen receptor (CAR) T-cell therapy has achieved substantial clinical outcomes for tumors, especially for hematological malignancies. However, extending the duration of remission, reduction of relapse for hematological malignancies and improvement of the anti-tumor efficacy for solid tumors are challenges for CAR-T cells immunotherapy. Besides the endeavors to enhance the functionality of CAR-T cell per se, optimization of the infusion and delivery strategies facilitates the breakthrough of the hurdles that limited the efficacy of this cancer immunotherapy. Here, we summarized the infusion and delivery strategies of CAR-T cell therapies under pre-clinical study, clinical trials and on-market status, through which the improvements of safety and efficacy for hematological and solid tumors were analyzed. Of note, novel infusion and delivery strategies, including local-regional infusion, biomaterials bearing the CAR-T cells and multiple infusion technique, overcome many limitations of CAR-T cell therapy. This review provides hints to determine infusion and delivery strategies of CAR-T cell cancer immunotherapy to maximize clinical benefits.

CAR-T Cell Therapy and the Gut Microbiota

Chimeric antigen receptor (CAR) - T cell cancer therapy has yielded promising results in treating hematologic malignancies in clinical studies, and a growing number of CAR-T regimens are approved for clinical usage. While the therapy is considered of great potential in expanding the cancer immunotherapy arsenal, more than half of patients receiving CAR-T infusions do not respond, while others develop significant adverse effects, collectively indicating a need for optimization of CAR-T treatment to the individual. The microbiota is increasingly suggested as a major modulator of immunotherapy responsiveness. Studying causal microbiota roles possibly contributing to CAR-T therapy efficacy, adverse effects reduction, and prediction of patient responsiveness constitutes an exciting area of active research. Herein, we discuss the latest developments implicating human microbiota involvement in CAR-T therapy, while highlighting challenges and promises in harnessing the microbiota as a predictor and modifier of CAR-T treatment towards optimized efficacy and minimization of treatment-related adverse effects.

Challenges in neoantigen-directed therapeutics

A fundamental prerequisite for the efficacy of cancer immunotherapy is the presence of functional, antigen-specific T cells within the tumor. Neoantigen-directed therapy is a promising strategy that aims at targeting the host's immune response against tumor-specific antigens, thereby eradicating cancer cells. Initial forays have been made in clinical environments utilizing vaccines and adoptive cell therapy; however, many challenges lie ahead. We provide an in-depth overview of the current state of the field with an emphasis on in silico neoantigen discovery and the clinical aspects that need to be addressed to unlock the full potential of this therapy.

Efficacy of adoptively transferred allogeneic CIK cells on colorectal cancer: Augmentative antitumoral effects of GvHD

OBJECTIVE

A preclinical study was designed to evaluate the effects of adoptively transferred cytokine-induced killer (CIK) cells on colorectal adenocarcinoma.

METHODS

Forty NOG mice bearing HT-29 xenograft tumors were developed and equally divided into 2 groups of treatment and control. The mice in the treatment group received cumulatively 40-60 × 10⁶ CIK cells in four divided doses.

RESULTS

Median tumor doubling times for HT-29 xenograft tumors in the treatment and control groups were found to be 8.98 and 4.32 days; respectively. The treatment resulted in tumor growth delay (TGD) of 52.5 %. CIK cell-induced log cell kill (LCK) was found to be 0.67, which implies reduction of 78.6 % of neoplastic colorectal cells. Median length of survival in the treated mice was significantly longer than controls (57 (41-63) vs 41 (31-57) days, P < 0.001). Mice in the treatment group experienced graft-versus-host disease (GvHD) from median of day 13th after the cell therapy. LCK and TGD significantly increased after emergence of GvHD. After necropsy, tumors of the treatment group contained high levels of human-originated CD3⁺, CD4⁺ and CD8⁺ cells and showed significantly lower mitotic counts (P < 0.001) and residual tumor scores (P = 0.005) than the controls (entirely negative for the mentioned CD markers). Ninety percent of the treated mice were found to be responding.

CONCLUSIONS

Adoptive transfer of allogeneic CIK cells may be an efficient antitumoral therapy for colorectal cancer. Allogeneic CIK cell-mediated GvHD may contribute to amplification of graft-versus-tumor effects of the cellular therapy.

High CENPA expression in papillary renal cell carcinoma tissues is associated with poor prognosis

OBJECTIVE

This work focused on investigating the relation of centromeric protein A (CENPA) gene expression with prognosis of papillary renal cell carcinoma (PRCC).

METHODS

We obtained data from PRCC cases in TCGA. Thereafter, CENPA levels between the paired PRCC and matched non-carcinoma samples were analyzed by Wilcoxon rank-sum test, while the relations of clinicopathological characteristics with CENPA level were examined by logistic regression and Wilcoxon rank-sum test. The prognostic value of CENPA was assessed by plotting the receiver operating feature curve (ROC) and calculating the value of area under curve (AUC). In addition, relations between clinicopathological characteristics and PRCC survival were analyzed through Kaplan-Meier (KM) and Cox regression analyses. After dividing the total number of patients into the trial cohort and the validation cohort in a ratio of 7:3, we constructed a nomogram in trial cohort according to multivariate Cox regression results for predicting how CENPA affected patient survival and used the calibration curve to verify its accuracy in both cohorts. We also determined CENPA levels within cancer and matched non-carcinoma samples through immunohistochemistry (IHC). Finally, we utilized functional enrichment for identifying key pathways related to differentially expressed genes (DEGs) between PRCC cases with CENPA up-regulation and down-regulation.

RESULTS

CENPA expression enhanced in PRCC tissues compared with healthy counterparts (P < 0.001). CENPA up-regulation was related to pathological TNM stage and clinical stage (P < 0.05). Meanwhile, the ROC curves indicated that CENPA had a remarkable diagnostic capacity for PRCC, and the expression of CENPA can significantly improve the predictive accuracy of pathological TNM stage and clinical stage for PRCC. As revealed by KM curves, PRCC cases with CENPA up-regulation were associated with poor survival compared with those with CENPA down-regulation (Risk ratio, RR = 3.07, 95% CI: 1.58-5.97, P = 0.001). In the meantime, univariate as well as multivariate analysis showed an independent association of CENPA with overall survival (OS, P < 0.05) and the nomogram demonstrated superior predictive ability in both cohorts. IHC analysis indicated that PRCC cases showed an increased CENPA positive rate compared with controls. As revealed by functional annotations, CENPA was enriched into pathways associated with neuroactive ligand receptor interactions, cytokine receptor interactions, extracellular matrix regulators, extracellular matrix glycoproteins and nuclear matrisome.

CONCLUSION

CENPA expression increases within PRCC samples, which predicts dismal PRCC survival. CENPA may become a molecular prognostic marker and therapeutic target for PRCC patients.

Impact of General Factors on Glioma Immunotherapy

Glioma remains the most common malignant tumor in the brain and is also the most difficult to treat. Immunotherapy achieving long-lasting tumor remission in multiple cancer types has received considerable attention due to its potential to improve the treatment outcomes of patients with glioma. However, clinical trials have not yet demonstrated major improvements in prognoses, which might be attributable to the extrinsic components and intrinsic mechanisms involved in the tumor microenvironment and immune system. It is particularly noteworthy that there is emerging evidence that current routine treatment modalities and the physical and psychological characteristics of patients have different impacts on the efficacy of glioma immunotherapy. This article addresses how these factors interact with the host immune system and tumor microenvironment, and highlights their potential roles in glioma immunotherapy, with the ultimate goal of developing better immunotherapy-based personalized medicine strategies.

Overcoming biological barriers to improve solid tumor immunotherapy

Cancer immunotherapy has been at the forefront of therapeutic interventions for many different tumor types over the last decade. While the discovery of immunotherapeutics continues to occur at an accelerated rate, their translation is often hindered by a lack of strategies to deliver them specifically into solid tumors. Accordingly, significant scientific efforts have been dedicated to understanding the underlying mechanisms that govern their delivery into tumors and the subsequent immune modulation. In this review, we aim to summarize the efforts focused on overcoming tumor-associated biological barriers and enhancing the potency of immunotherapy. We summarize the current understanding of biological barriers that limit the entry of intravascularly administered immunotherapies into the tumors, in vitro techniques developed to investigate the underlying transport processes, and delivery strategies developed to overcome the barriers. Overall, we aim to provide the reader with a framework that guides the rational development of technologies for improved solid tumor immunotherapy.

Critical View of Novel Treatment Strategies for Glioblastoma: Failure and Success of Resistance Mechanisms by Glioblastoma Cells

According to the invasive nature of glioblastoma, which is the most common form of malignant brain tumor, the standard care by surgery, chemo- and radiotherapy is particularly challenging. The presence of glioblastoma stem cells (GSCs) and the surrounding tumor microenvironment protects glioblastoma from recognition by the immune system. Conventional therapy concepts have failed to completely remove glioblastoma cells, which is one major drawback in clinical management of the disease. The use of small molecule inhibitors, immunomodulators, immunotherapy, including peptide and mRNA vaccines, and virotherapy came into focus for the treatment of glioblastoma. Although novel strategies underline the benefit for anti-tumor effectiveness, serious challenges need to be overcome to successfully manage tumorigenesis, indicating the significance of developing new strategies. Therefore, we provide insights into the application of different medications in combination to boost the host immune system to interfere with immune evasion of glioblastoma cells which are promising prerequisites for therapeutic approaches to treat glioblastoma patients.

High SEC61G expression predicts poor prognosis in patients with Head and Neck Squamous Cell Carcinomas

Background: Overexpression of the membrane protein SEC61 translocon gamma subunit (SEC61G) has been observed in a variety of cancers; however, its role in head and neck squamous cell carcinomas (HNSCC) is unknown. This study aimed to elucidate the relationship between SEC61G and HNSCC based on data from The Cancer Genome Atlas (TCGA) database. Methods: Data for HNSCC patients were collected from TCGA and the expression level of SEC61G was compared between paired HNSCC and normal tissues using the Wilcoxon rank-sum test. The relationship between clinicopathologic features and SEC61G expression was also analyzed using the Wilcoxon rank-sum test and logistic regression. Receiver operating characteristic (ROC) curves were generated to evaluate the value of SEC61G as a binary classifier using the area under the curve (AUC value). The association of clinicopathologic characteristics with prognosis in HNSCC patients was assessed using Cox regression and the Kaplan-Meier methods. A nomogram, based on Cox multivariate analysis, was used to predict the impact of SEC61G on prognosis. Functional enrichment analysis was performed to determine the hallmark pathways associated with differentially expressed genes in HNSCC patients exhibiting high and low SEC61G expression. Results: The expression of SEC61G was significantly elevated in HNSCC tissues compared to normal tissues (P < 0.001). The high expression of SEC61G was significantly correlated with the T stage, M stage, clinical stage, TP53 mutation status, PIK3CA mutation status, primary therapy outcome, and cervical lymph node dissection (all P < 0.05). Meanwhile, ROC curves suggested the significant diagnostic ability of SEC61G for HNSCC (AUC = 0.923). Kaplan-Meier survival analysis showed that patients with HNSCC characterized by high SEC61G expression had a poorer prognosis than patients with low SEC61G expression (hazard ratio = 1.95, 95% confidence interval 1.48-2.56, P < 0.001). Univariate and multivariate analyses revealed that SEC61G was independently associated with overall survival (P = 0.027). Functional annotations indicated that SEC61G is involved in pathways related to translation and regulation of SLITs/ROBOs expression, SRP-dependent co-translational protein targeting to the membrane, nonsense-mediated decay, oxidative phosphorylation, and Parkinson's disease. Conclusion: SEC61G plays a vital role in HNSCC progression and prognosis; it may, therefore, serve as an effective biomarker for the prediction of patient survival.

Enhancing CAR-T cell efficacy in solid tumors by targeting the tumor microenvironment

Chimeric antigen receptor (CAR)-T cell therapy has achieved successful outcomes against hematological malignancies and provided a new impetus for treating solid tumors. However, the efficacy of CAR-T cells for solid tumors remains unsatisfactory. The tumor microenvironment has an important role in interfering with and inhibiting the effector function of immune cells, among which upregulated inhibitory checkpoint receptors, soluble suppressive cytokines, altered chemokine expression profiles, aberrant vasculature, complicated stromal composition, hypoxia and abnormal tumor metabolism are major immunosuppressive mechanisms. In this review, we summarize the inhibitory factors that affect the function of CAR-T cells in tumor microenvironment and discuss approaches to improve CAR-T cell efficacy for solid tumor treatment by targeting those barriers.

Promises and challenges of adoptive T-cell therapies for solid tumours

Cancer is a leading cause of death worldwide and, despite new targeted therapies and immunotherapies, many patients with advanced-stage- or high-risk cancers still die, owing to metastatic disease. Adoptive T-cell therapy, involving the autologous or allogeneic transplant of tumour-infiltrating lymphocytes or genetically modified T cells expressing novel T-cell receptors or chimeric antigen receptors, has shown promise in the treatment of cancer patients, leading to durable responses and, in some cases, cure. Technological advances in genomics, computational biology, immunology and cell manufacturing have brought the aspiration of individualised therapies for cancer patients closer to reality. This new era of cell-based individualised therapeutics challenges the traditional standards of therapeutic interventions and provides opportunities for a paradigm shift in our approach to cancer therapy. Invited speakers at a 2020 symposium discussed three areas-cancer genomics, cancer immunology and cell-therapy manufacturing-that are essential to the effective translation of T-cell therapies in the treatment of solid malignancies. Key advances have been made in understanding genetic intratumour heterogeneity, and strategies to accurately identify neoantigens, overcome T-cell exhaustion and circumvent tumour immunosuppression after cell-therapy infusion are being developed. Advances are being made in cell-manufacturing approaches that have the potential to establish cell-therapies as credible therapeutic options. T-cell therapies face many challenges but hold great promise for improving clinical outcomes for patients with solid tumours.

A Palette of Cytokines to Measure Anti-Tumor Efficacy of T Cell-Based Therapeutics

Cytokines are key molecules within the tumor microenvironment (TME) that can be used as biomarkers to predict the magnitude of anti-tumor immune responses. During immune monitoring, it has been customary to predict outcomes based on the abundance of a single cytokine, in particular IFN-γ or TGF-β, as a readout of ongoing anti-cancer immunity. However, individual cytokines within the TME can exhibit dual opposing roles. For example, both IFN-γ and TGF-β have been associated with pro- and anti-tumor functions. Moreover, cytokines originating from different cellular sources influence the crosstalk between CD4+ and CD8+ T cells, while the array of cytokines expressed by T cells is also instrumental in defining the mechanisms of action and efficacy of treatments. Thus, it becomes increasingly clear that a reliable readout of ongoing immunity within the TME will have to include more than the measurement of a single cytokine. This review focuses on defining a panel of cytokines that could help to reliably predict and analyze the outcomes of T cell-based anti-tumor therapies.

Effect of radiotherapy on T cell and PD-1 / PD-L1 blocking therapy in tumor microenvironment

Cancer is a worldwide problem that threatens human health. Radiotherapy plays an important role in a variety of cancer treatment methods. The administration of radiotherapy can alter the differentiation pathways and functions of T cells, which in turn improves the immune response of T cells. Radiotherapy can also induce up-regulation of PD-L1 expression, which means that it has great potential for enhancing the therapeutic effect of anti-PD-1/PD-L1 inhibitors and reducing the risk of drug resistance toward them. At present, the combination of radiotherapy and anti-PD-1/PD-L1 inhibitors has shown significant therapeutic effects in clinical tumor research. This review focuses on the mechanism of radiotherapy on T cells reported in recent years, as well as related research progress in the application of PD-1/PD-L1 blockers. It will provide a theoretical basis for the rational clinical application of radiotherapy combined with PD-1/PD-L1 inhibitors.

Systemic dendrimer delivery of triptolide to tumor-associated macrophages improves anti-tumor efficacy and reduces systemic toxicity in glioblastoma

Novel delivery strategies are necessary to effectively address glioblastoma without systemic toxicities. Triptolide is a therapy derived from the thunder god vine that has shown potent anti-proliferative and immunosuppressive properties but exhibits significant adverse systemic effects. Dendrimer-based nanomedicines have shown great potential for clinical translation of systemic therapies targeting neuroinflammation and brain tumors. Here we present a novel dendrimer-triptolide conjugate that specifically targets tumor-associated macrophages (TAMs) in glioblastoma from systemic administration and exhibits triggered release under intracellular and intratumor conditions. This targeted delivery improves phenotype switching of TAMs from pro- towards anti-tumor expression in vitro. In an orthotopic model of glioblastoma, dendrimer-triptolide achieved significantly improved amelioration of tumor burden compared to free triptolide. Notably, the triggered release mechanism of dendrimer-mediated triptolide delivery significantly reduced triptolide-associated hepatic and cardiac toxicities. These results demonstrate that dendrimers are a promising targeted delivery platform to achieve effective glioblastoma treatment by improving efficacy while reducing systemic toxicities.

"The Loss of Golden Touch": Mitochondria-Organelle Interactions, Metabolism, and Cancer

Mitochondria represent the energy hub of cells and their function is under the constant influence of their tethering with other subcellular organelles. Mitochondria interact with the endoplasmic reticulum, lysosomes, cytoskeleton, peroxisomes, and nucleus in several ways, ranging from signal transduction, vesicle transport, and membrane contact sites, to regulate energy metabolism, biosynthetic processes, apoptosis, and cell turnover. Tumorigenesis is often associated with mitochondrial dysfunction, which could likely be the result of an altered interaction with different cell organelles or structures. The purpose of the present review is to provide an updated overview of the links between inter-organellar communications and interactions and metabolism in cancer cells, with a focus on mitochondria. The very recent publication of several reviews on these aspects testifies the great interest in the area. Here, we aim at (1) summarizing recent evidence supporting that the metabolic rewiring and adaptation observed in tumors deeply affect organelle dynamics and cellular functions and vice versa; (2) discussing insights on the underlying mechanisms, when available; and (3) critically presenting the gaps in the field that need to be filled, for a comprehensive understanding of tumor cells’ biology. Chemo-resistance and druggable vulnerabilities of cancer cells related to the aspects mentioned above is also outlined.

NKp30 - A prospective target for new cancer immunotherapy strategies

Natural killer (NK) cells are an important arm of the innate immune system. They constitutively express the NKp30 receptor. NKp30-mediated responses are triggered by the binding of specific ligands e.g. tumour cell-derived B7-H6 and involve the secretion of cytotoxic mediators including TNF-α, IFN-γ, perforins and granzymes. The latter two constitute a target cell-directed response that is critical in the process of immunosurveillance. The structure of NKp30 is presented, focusing on the ligand-binding site, on the ligand-induced structural changes and on the experimental data available correlating structure and binding affinity. The translation of NKp30 structural changes to disease progression is also reviewed. NKp30 role in immunotherapy has been explored in chimeric antigen receptor T-cell (CAR-T) therapy. However, antibodies or small ligands targeting NKp30 have not yet been developed. The data reviewed herein unveil the key structural aspects that must be considered for drug design in order to develop novel immunotherapy approaches.

The SHH/GLI signaling pathway: a therapeutic target for medulloblastoma

INTRODUCTION

Medulloblastoma (MB) is a heterogeneous tumor of the cerebellum that is divided into four main subgroups with distinct molecular and clinical features. Sonic Hedgehog MB (SHH-MB) is the most genetically understood and occurs predominantly in childhood. Current therapies consist of aggressive and non-targeted multimodal approaches that are often ineffective and cause long-term complications. These problems intensify the need to develop molecularly targeted therapies to improve outcome and reduce treatment-related morbidities. In this scenario, Hedgehog (HH) signaling, a developmental pathway whose deregulation is involved in the pathogenesis of several malignancies, has emerged as an attractive druggable pathway for SHH-MB therapy.

AREAS COVERED

This review provides an overview of the advancements in the HH antagonist research field. We place an emphasis on Smoothened (SMO) and glioma-associated oncogene homolog (GLI) inhibitors and immunotherapy approaches that are validated in preclinical SHH-MB models and that have therapeutic potential for MB patients. Literature from Pubmed and data reported on ClinicalTrial.gov up to August 2020 were considered.

EXPERT OPINION

Extensive-omics analysis has enhanced our knowledge and has transformed the way that MB is studied and managed. The clinical use of SMO antagonists has yet to be determined, however, future GLI inhibitors and multitargeting approaches are promising.

NK cells in the tumor microenvironment: Prognostic and theranostic impact. Recent advances and trends

NK cells orchestrate the tumor destruction and control metastasis in a coordinated way with other immune cells of the tumor microenvironment. However, NK cell infiltration in the tumor microenvironment is limited, and tumor cells have developed numerous mechanisms to escape NK cell attack. As a result, NK cells that have been able to infiltrate the tumors are exhausted, and metabolically and functionally impaired. Depending this impairment the prognostic and theranostic values of NK cells differ depending on the studies, the type of cancer, the stage of tumor and the nature of the tumor microenvironment. Extensive studies have been done to investigate different strategies to improve the NK cell function, and nowadays, a battery of therapeutic tools are being tested, with promising results.

Engineering of chimeric natural killer cell receptors to develop precision adoptive immunotherapies for cancer

Natural killer (NK) cells are innate immune effectors which play a crucial role in recognizing and eliminating virally infected and cancerous cells. They effectively distinguish between healthy and distressed self through the integration of signals delivered by germline‐encoded activating and inhibitory cell surface receptors. The frequent up‐regulation of stress markers on genetically unstable cancer cells has prompted the development of novel immunotherapies that exploit such innate receptors. One prominent example entails the development of chimeric antigen receptors (CAR) that detect cell surface ligands bound by NK receptors, coupling this engagement to the delivery of tailored immune activating signals. Here, we review strategies to engineer CARs in which specificity is conferred by natural killer group 2D (NKG2D) or other NK receptor types. Multiple preclinical studies have demonstrated the remarkable ability of chimeric NK receptor‐targeted T cells and NK cells to effectively and specifically eliminate cancer cells and to reject established tumour burdens. Importantly, such systems act not only acutely but, in some cases, they also incite immunological memory. Moreover, CARs targeted with the NKG2D ligand binding domain have also been shown to disrupt the tumour microenvironment, through the targeting of suppressive T regulatory cells, myeloid‐derived suppressor cells and tumour vasculature. Collectively, these findings have led to the initiation of early‐phase clinical trials evaluating both autologous and allogeneic NKG2D‐targeted CAR T cells in the haematological and solid tumour settings.

Endogenous T cells prevent tumor immune escape following adoptive T cell therapy

While the outcome of adoptive T cell therapy (ACT) is typically correlated with the functionality of the inoculated T cells, the role of the endogenous T cells is unknown. The success of checkpoint blockade therapy has demonstrated the potentially curative value of preexisting tumor-primed T cells in cancer treatment. Given the results from checkpoint blockade therapy, we hypothesized that endogenous T cells contribute to long-term survival following ACT. Here, we describe a therapeutic approach combining ACT with an oncolytic vaccine that allows simultaneous analysis of antitumor immunity mediated by transferred and endogenous T cells. We found that, in addition to promoting the expansion and tumor infiltration of the transferred T cells, oncolytic vaccines boosted tumor-primed host T cells. We determined that transferred T cells contributed to rapid destruction of large tumor masses while endogenous T cells concurrently prevented the emergence of antigen-loss variants. Moreover, while transferred T cells disappeared shortly after tumor regression, endogenous T cells secured long-term memory with a broad repertoire of antigen specificity. Our findings suggest that this combination strategy may exploit the full potential of ACT and tumor-primed host T cells to eliminate the primary tumor, prevent immune escape, and provide long-term protective memory.

Cellular Immunotherapy and Locoregional Administration of CAR T-Cells in Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is a treatment recalcitrant tumor with a poor overall survival (OS). Current approved treatment consists of first line chemotherapy that only modestly increases OS, illustrating the desperate need for other treatment options in MPM. Unfortunately, clinical studies that investigate the effectivity of checkpoint inhibitor (CI) treatment failed to improve clinical outcome over current applied therapies. In general, MPM is characterized as an immunological cold tumor with low T-cell infiltration, which could explain the disappointing results of clinical trials investigating CI treatment in MPM. Currently, many other therapeutic approaches, such as cellular therapies and cancer vaccines are investigated that could induce a tumor-specific immune response and increase of the number of tumor-infiltrating lymphocytes. In this review we will discuss these novel treatment approaches for MPM.

Just eat it: A review of CD47 and SIRP-α antagonism

The mammalian immune system consists of two distinct arms, nonspecific innate and more specific adaptive, with the innate immune response as the first line of defense and protection, which primes and amplifies subsequent adaptive responses. On the basis of this binary immune interplay, stimulation of T cells through checkpoint inhibitors (CIs), which bypasses innate involvement, seems likely to engender suboptimal or incomplete anticancer immunity, given that the successful induction of effect or responses depends on two-way innate/adaptive coordination. Indeed, the majority of patients-70%-80%, do not respond to CIs, which is potentially problematic if access to more optimal standard therapies is withheld or delayed in favor of ineffective or only marginally effective anti-PD-1/PD-L1 treatment. Therefore, stimulation of the innate immune response in combination with CIs (or other inducers of T cell cytotoxicity) has the potential to make the immune system "whole" and thereby to enhance and broaden the anti-tumor activity of PD-1/PD-L1 inhibitors for example, in relatively nonimmunogenic or "cold" tumor types. A critical innate macrophage immune checkpoint and druggable target is the antiphagocytic and "marker of self" CD47-SIRPα pathway, which is co-opted by cancer cells to mediate escape from immune-mediated clearance and checkpoint inhibition. This review summarizes the status of key CD47 antagonists in clinical trials, including the biologics, Hu5F9-G4 (5F9), TTI-621, and ALX148, as well as the small molecule, RRx-001, now in a Phase 3 clinical trial, which has not been previously included in CD47-SIRPα reviews focused on biologics. Hu5F9-G4 (5F9), TTI-621, ALX148, and RRx-001 are chosen as compounds with potentially promising data that have advanced the farthest in clinical development.

The Antitumor Efficacy of β-Elemene by Changing Tumor Inflammatory Environment and Tumor Microenvironment

Inflammatory mediators and inflammatory cells in the inflammatory microenvironment promote the transformation of normal cells to cancer cells in the early stage of cancer, promote the growth and development of cancer cells, and induce tumor immune escape. The monomeric active ingredient β-elemene is extracted from the traditional Chinese medicine Curcuma wenyujin and has been proven to have good anti-inflammatory and antitumor activities in clinical applications for more than 20 years in China. Recent studies have found that this traditional Chinese medicine plays a vital role in macrophage infiltration and M2 polarization, as well as in regulating immune disorders, and it even regulates the transcription factors NF-κB and STAT3 to alter inflammation, tumorigenesis, and development. In addition, β-elemene regulates not only different inflammatory factors (such as TNF-α, IFN, TGF-β, and IL-6/10) but also oxidative stress in vivo and in vitro. The excellent anti-inflammatory and antitumor effects of β-elemene and its ability to alter the inflammatory microenvironment of tumors have been gradually elaborated. Although the study of monomeric active ingredients in traditional Chinese medicines is insufficient in terms of quality and quantity, the pharmacological effects of more active ingredients of traditional Chinese medicines will be revealed after β-elemene.

CAR T‑cell therapy for gastric cancer: Potential and perspective (Review)

Gastric cancer (GC) is one of the most frequently diagnosed digestive malignancies and is the third leading cause of cancer‑associated death worldwide. Delayed diagnosis and poor prognosis indicate the urgent need for new therapeutic strategies. The success of chimeric antigen receptor (CAR) T‑cell therapy for chemotherapy‑refractory hematological malignancies has inspired the development of a similar strategy for GC treatment. Although using CAR T‑cells against GC is not without difficulty, results from preclinical studies remain encouraging. The current review summarizes relevant preclinical studies and ongoing clinical trials for the use of CAR T‑cells for GC treatment and investigates possible toxicities, as well as current clinical experiences and emerging approaches. With a deeper understanding of the tumor microenvironment, novel target epitopes and scientific‑technical progress, the potential of CAR T‑cell therapy for GC is anticipated in the near future.

Listeria monocytogenes cancer vaccines: bridging innate and adaptive immunity

Purpose of the Review

Immunotherapy has emerged as a promising cancer treatment, however success in only select clinical indications underscores the need for novel approaches. Recently Listeria monocytogenes-based vaccines have been developed to drive tumor specific T-cell responses. Here, we discuss recent preclinical studies using L. monocytogenes vaccines, innate immune pathways that influence T-cell priming, and new vaccine strategies in clinical trials.

Recent Findings

Recent studies indicate that in addition to inducing antigen specific T-cell responses, L. monocytogenes vaccines remodel the TME. In addition, several innate immune pathways influence adaptive immune responses to L. monocytogenes and modulating these pathways holds promise to enhance anti-tumor T-cell responses.

Summary

The interplay between innate and adaptive immune responses to L. monocytogenes is poorly understood. Understanding these interactions will facilitate the design of better anti-cancer vaccines and improved use of combination therapies.

Blockade of CTLA-4 and PD-1 Enhances Adoptive T-cell Therapy Efficacy in an ICOS-Mediated Manner

Adoptive transfer of tumor-reactive T cells (ACT) has led to modest clinical benefit in the treatment of solid tumors. Failures with this therapy are primarily due to inadequate infiltration and poor function of adoptively transferred cells in the tumor microenvironment. To improve the efficacy of ACT, we combined ACT with dual blockade of CTLA-4 and PD-1. Treatment with anti-CTLA-4 plus anti-PD-1 compared with monotherapy resulted in durable antitumor responses, enhanced effector function of ACT, utilizing PMEL-1 transgenic (Tg⁺) CD8⁺ T cells, and improved survival. Using PMEL-1ICOS^-/- mice, we showed that deletion of the inducible T-cell costimulator (ICOS) receptor abolished the therapeutic benefits, with selective downregulation of Eomesodermin (Eomes), interferon gamma (IFNγ), and perforin. Higher expression of IFNγ and Eomes was noted in human ICOS^hi CD8⁺ T cells compared with ICOS^low counterparts. Together, our data provide direct evidence that ACT combined with immune-checkpoint therapy confers durable antitumor responses, which largely depended on CD8⁺ T-cell-intrinsic expression of ICOS. Our study provides a foundation of testing combinatorial therapy of ACT of CD8 T cells and dual blocking of CTLA-4 and PD-1 in patients with melanoma.

Quantitative high-throughput screening assays for the discovery and development of SIRPα-CD47 interaction inhibitors

CD47 is an immune checkpoint molecule that downregulates key aspects of both the innate and adaptive anti-tumor immune response via its counter receptor SIRPα, and it is expressed at high levels in a wide variety of tumor types. This has led to the development of biologics that inhibit SIRPα engagement including humanized CD47 antibodies and a soluble SIRPα decoy receptor that are currently undergoing clinical trials. Unfortunately, toxicological issues, including anemia related to on-target mechanisms, are barriers to their clinical advancement. Another potential issue with large biologics that bind CD47 is perturbation of CD47 signaling through its high-affinity interaction with the matricellular protein thrombospondin-1 (TSP1). One approach to avoid these shortcomings is to identify and develop small molecule molecular probes and pretherapeutic agents that would (1) selectively target SIRPα or TSP1 interactions with CD47, (2) provide a route to optimize pharmacokinetics, reduce on-target toxicity and maximize tissue penetration, and (3) allow more flexible routes of administration. As the first step toward this goal, we report the development of an automated quantitative high-throughput screening (qHTS) assay platform capable of screening large diverse drug-like chemical libraries to discover novel small molecules that inhibit CD47-SIRPα interaction. Using time-resolved Förster resonance energy transfer (TR-FRET) and bead-based luminescent oxygen channeling assay formats (AlphaScreen), we developed biochemical assays, optimized their performance, and individually tested them in small-molecule library screening. Based on performance and low false positive rate, the LANCE TR-FRET assay was employed in a ~90,000 compound library qHTS, while the AlphaScreen oxygen channeling assay served as a cross-validation orthogonal assay for follow-up characterization. With this multi-assay strategy, we successfully eliminated compounds that interfered with the assays and identified five compounds that inhibit the CD47-SIRPα interaction; these compounds will be further characterized and later disclosed. Importantly, our results validate the large library qHTS for antagonists of CD47-SIRPα interaction and suggest broad applicability of this approach to screen chemical libraries for other protein-protein interaction modulators.

Bispecific anti-CD3 x anti-B7-H3 antibody mediates T cell cytotoxic ability to human melanoma in vitro and in vivo

Inhibition of the B7-H3 immune checkpoint is reported to limit the tumor growth of B7-H3⁺ tumors. In this study, we demonstrated B7-H3 expression in human melanoma cells, including a primary culture and several cell lines. Furthermore, we investigated whether B7-H3 could serve as a target for T cell-mediated immunotherapy against melanoma. The cytotoxic capacity of activated T cells (ATCs) armed with an anti-CD3 x anti-B7-H3 bispecific antibody (B7-H3Bi-Ab) to melanoma cells was measured using a bioluminescent signal through a luciferase reporter on tumor cells. In contrast to unarmed ATCs, B7-H3Bi-Ab-armed ATCs exhibited increased cytotoxicity against melanoma cells at effector/target ratios from 1:1 to 20:1. Moreover, B7-H3Bi-Ab-armed ATCs secreted more interferin-gamma (IFN-γ), accompanied by higher levels of activating marker CD69 and CD25 expression. Infusion of B7-H3Bi-Ab-armed ATCs suppressed melanoma growth in a xenograft mouse model. Taken together, our results indicate that B7-H3Bi-Ab-armed ATCs may be a promising approach to immunotherapy for melanoma patients.

OCT4&SOX2-specific cytotoxic T lymphocytes plus programmed cell death protein 1 inhibitor presented with synergistic effect on killing lung cancer stem-like cells in vitro and treating drug-resistant lung cancer mice in vivo

This study aimed to investigate the synergistic effect of octamer-binding transcription factor 4 and sex determining region Y-box 2 (OCT4&SOX2)-specific cytotoxic T lymphocytes (CTLs) and programmed cell death protein 1 (PD-1) inhibitor on killing lung cancer stem-like cells (LCSCs) and their efficacy in treating drug-resistant lung cancer (DRLC) mice. OCT4&SOX2-specific CTLs and PD-1 inhibitor with differed doses were applied to treat PC9 cells and PC9 LCSCs. Cell counting kit-8 (CCK8) assay and flow cytometry (FCM) assay with carboxyfluorescein diacetate/succinimidyl ester staining target cells before treatment and propidium iodide (PI) staining dead cells after treatment were conducted to detect the cytotoxic activity. DRLC mice were constructed by injection of PC9 LCSCs suspension and Matrigel into left lung of SD mice. DRLC mice were randomly divided into five groups: control group, cytomegalovirus (CMV) pp65 CTLs group, OCT4&SOX2 CTLs group, PD-1 inhibitor group, and OCT4&SOX2 CTLs + PD-1 inhibitor group. In vitro, both CCK8 assay and FCM assay disclosed that OCT4&SOX2-specific CTLs plus PD-1 inhibitor presented with elevated cytotoxic activity on PC9 cells and PC9 LCSCs. In vivo, tumor volume and tumor weight were decreased, while tumor necrosis and tumor apoptosis were increased in OCT4&SOX2 CTLs group than CMV pp65 CTLs group and control group, and in OCT4&SOX2 CTLs + PD-1 inhibitor group than OCT4&SOX2 CTLs group and PD-1 inhibitor group. In addition, CD8 expression was increased while OCT4&SOX2 expressions were decreased in OCT4&SOX2 CTLs + PD-1 inhibitor group than OCT4&SOX2 CTLs group and PD-1 inhibitor group. In conclusion, OCT4&SOX2-specific CTLs and PD-1 inhibitor presented with the synergistic effect on killing LCSCs in vitro and treating DRLC mice in vivo.

Bi-specific and tri-specific antibodies- the next big thing in solid tumor therapeutics

Antibody-based therapy has revitalized the world of cancer therapeutics since rituximab was first approved for the treatment of Non-Hodgkin's Lymphoma. Monoclonal antibodies against cancer antigens have been successful strategies for only a handful of cancer types due to many reasons including lack of antibody specificity and complex nature of tumor milieu which interfere with antibody efficacy. Polyspecific antibodies are promising class of anti-cancer agents which can be directed at multiple tumor antigens to eradicate tumor cells more precisely and effectively. They may overcome some of these limitations and have already changed treatment landscape for some malignancies such as B cell acute lymphoblastic leukemia. Pre-clinical studies and early phase clinical trials have demonstrated that this approach may be an effective strategy even for solid tumors. This review focuses on the development of bispecific and trispecific antibody therapy for the treatment of solid tumor malignancies and highlights the potential they hold for future therapies to come.

The Interplay between Circulating Tumor Cells and the Immune System: From Immune Escape to Cancer Immunotherapy

Circulating tumor cells (CTCs) have aroused increasing interest not only in mechanistic studies of metastasis, but also for translational applications, such as patient monitoring, treatment choice, and treatment change due to tumor resistance. In this review, we will assess the state of the art about the study of the interactions between CTCs and the immune system. We intend to analyze the impact that the cells of the immune system have in limiting or promoting the metastatic capability of CTCs. To this purpose, we will examine studies that correlate CTCs, immune cells, and patient prognosis, and we will also discuss relevant animal models that have contributed to the understanding of the mechanisms of immune-mediated metastasis. We will then consider some studies in which CTCs seem to play a promising role in monitoring cancer patients during immunotherapy regimens. We believe that, from an accurate and profound knowledge of the interactions between CTCs and the immune system, new immunotherapeutic strategies against cancer might emerge in the future.

Durable regression of Medulloblastoma after regional and intravenous delivery of anti-HER2 chimeric antigen receptor T cells

Background

Standard-of-care therapies for treating pediatric medulloblastoma have long-term side effects, even in children who are cured. One emerging modality of cancer therapy that could be equally effective without such side effects would be chimeric antigen receptor (CAR) T cells. Knowing that human epidermal growth factor receptor 2 (HER2) is overexpressed in many medulloblastomas and has been used as a CAR T target before, we sought to evaluate the efficacy of more sophisticated anti-HER2 CAR T cells, as well as the feasibility and efficacy of different routes of delivering these cells, for the treatment of pediatric medulloblastoma.

Methods

Daoy, D283 and D425 medulloblastoma cell lines were characterized by flow cytometry to evaluate HER2 expression. Anti-tumor efficacy of HER2-BBz-CAR T cells in vitro was performed using cytokine release and immune cytotoxicity assays compared to control CD19 CAR T cells. In vivo, Daoy and D283 tumor cells were orthotopically implanted in the posterior fossa of NOD.Cg-Prkdc^scidIl2rg^tm1Wjl/SzJ (NSG) mice and treated with regional or intravenous HER2-BBz-CAR T cells or control CD19 CAR T cells. Non-human primates (NHPs) bearing ventricular and lumbar reservoirs were treated with target autologous cells bearing extracellular HER2 followed by autologous HER2-CAR T cells intraventricularly. Cerebrospinal fluid and blood were collected serially to measure the persistence of delivered cells and cytokines.

Results

HER2-BBz-CAR T cells effectively clear medulloblastoma orthotopically implanted in the posterior fossa of NSG mice via both regional and intravenous delivery in xenograft models. Intravenous delivery requires a log higher dose compared to regional delivery. NHPs tolerated intraventricular delivery of autologous cells bearing extracellular HER2 followed by HER2-BBz-CAR T cells without experiencing any systemic toxicity.

Conclusions

HER2-BBz-CAR T cells show excellent pre-clinical efficacy in vitro and in mouse medulloblastoma models, and their intraventricular delivery is feasible and safe in NHPs. A clinical trial of HER2-BBz-CAR T cells directly delivered into cerebrospinal fluid should be designed for patients with relapsed medulloblastoma.

Electronic supplementary material

The online version of this article (10.1186/s40425-018-0340-z) contains supplementary material, which is available to authorized users.

Role of immune system in tumor progression and carcinogenesis

Tumor micro-environment has potential to customize the behavior of the immune cell according to their need. In immune-eliminating phase, immune cells eliminate transformed cells but after tumor establishment innate and adaptive immune cells synergistically provide shelter as well as fulfill their requirement that helps in progression. In between eliminating and establishment phase, equilibrium and escaping phase regulate the immune cells response. During immune-escaping, (1) the antigenic response generated is either inadequate, or focused entirely on tolerance, and (2) immune response generated is specific and effective, but the tumor skips immune recognition. In this review, we are discussing the critical role of immune cells and their cytokines before and after the establishment of tumor which might play a critical role during immunotherapy.

Epidermal growth factor receptor and EGFRvIII in glioblastoma: signaling pathways and targeted therapies

Amplification of epidermal growth factor receptor (EGFR) and its active mutant EGFRvIII occurs frequently in glioblastoma (GBM). While EGFR and EGFRvIII play critical roles in pathogenesis, targeted therapy with EGFR-tyrosine kinase inhibitors (TKIs) or antibodies has only shown limited efficacy in patients. Here we discuss signaling pathways mediated by EGFR/EGFRvIII, current therapeutics, and novel strategies to target EGFR/EGFRvIII-amplified GBM.

Development of Molecularly Targeted Agents and Immunotherapies in Glioblastoma: A Personalized Approach

Over the past decade, precision cancer medicine has driven major advances in the management of advanced solid tumours with the identification and targeting of putative driver aberrations transforming the clinical outcomes across multiple cancer types. Despite pivotal advances in the characterization of genomic landscape of glioblastoma, targeted agents have shown minimal efficacy in clinical trials to date, and patient survival remains poor. Immunotherapy strategies similarly have had limited success. Multiple deficiencies still exist in our knowledge of this complex disease, and further research is urgently required to overcome these critical issues. This review traces the path undertaken by the different therapeutics assessed in glioblastoma and the impact of precision medicine in this disease. We highlight challenges for precision medicine in glioblastoma, focusing on the issues of tumour heterogeneity, pharmacokinetic-pharmacodynamic optimization and outline the modern hypothesis-testing strategies being undertaken to address these key challenges.

Immunological network analysis in HPV associated head and neck squamous cancer and implications for disease prognosis

Human papillomavirus-positive (HPV+) head and neck squamous cell cancer (HNSCC) exhibits a better prognosis than HPV-negative (HPV-) HNSCC. This difference may in part be due to enhanced immune activation in the HPV+ HNSCC tumor microenvironment. To characterize differences in immune activation between HPV+ and HPV- HNSCC tumors, we identified and annotated differentially expressed genes based upon mRNA expression data from The Cancer Genome Atlas (TCGA). Immune network between immune cells and cytokines was constructed by using single sample Gene Set Enrichment Analysis and conditional mutual information. Multivariate Cox regression analysis was used to determine the prognostic value of immune microenvironment characterization. A total of 1673 differentially expressed genes were functionally annotated. We found that genes upregulated in HPV+ HNSCC are enriched in immune-associated processes. And the up-regulated gene sets were validated by Gene Set Enrichment Analysis. The microenvironment of HPV+ HNSCC exhibited greater numbers of infiltrating B and T cells and fewer neutrophils than HPV- HNSCC. These findings were validated by two independent datasets in the Gene Expression Omnibus (GEO) database. Further analyses of T cell subtypes revealed that cytotoxic T cell subtypes predominated in HPV+ HNSCC. In addition, the ratio of M1/M2 macrophages was much higher in HPV+ HNSCC. The infiltration of these immune cells was correlated with differentially expressed cytokine-associated genes. Enhanced infiltration of B cells and CD8+ T cells were identified as independent protective factors, while high neutrophil infiltration was a risk enhancing factor for HPV+ HNSCC patients. A schematic model of immunological network was established for HPV+ HNSCC to summarize our findings.

A phase I clinical trial of RNF43 peptide-related immune cell therapy combined with low-dose cyclophosphamide in patients with advanced solid tumors

The objective of this study was to investigate the safety and the tolerability of combined cellular immunotherapy with low-dose cyclophosphamide (CPA) in patients with advanced solid tumors. This study targeted a novel tumor-associated antigen, ring finger protein 43 (RNF43). Eligible patients were resistant to standard therapy, HLA-A*24:02- or A*02:01-positive and exhibiting high RNF43 expression in their tumor cells. They were administered 300 mg/m2 CPA followed by autologous lymphocytes, preliminarily cultured with autologous RNF43 peptide-pulsed dendritic cells (DCs), RNF43 peptide-pulsed DCs and systemic low dose interleukin-2. The primary endpoint was safety whereas the secondary endpoint was immunological and clinical response to treatment. Ten patients, in total, were enrolled in this trial. Primarily, no adverse events greater than Grade 3 were observed. Six out of 10 patients showed stable disease (SD) on day 49, while 4 other patients showed progressive disease. In addition, one patient with SD exhibited a partial response after the second trial. The frequency of regulatory T cells (Tregs) in patients with SD significantly decreased after CPA administration. The ratio of interferon-γ-producing, tumor-reactive CD8+ T cells increased with time in patients with SD. We successfully showed that the combination of immune cell therapy and CPA was safe, might induce tumor-specific immune responses and clinical efficacy, and was accompanied by a decreased ratio of Tregs in patients with RNF43-positive advanced solid tumors.

Breakthroughs in modern cancer therapy and elusive cardiotoxicity: Critical research-practice gaps, challenges, and insights

To date, five cancer treatment modalities have been defined. The three traditional modalities of cancer treatment are surgery, radiotherapy, and conventional chemotherapy, and the two modern modalities include molecularly targeted therapy (the fourth modality) and immunotherapy (the fifth modality). The cardiotoxicity associated with conventional chemotherapy and radiotherapy is well known. Similar adverse cardiac events are resurging with the fourth modality. Aside from the conventional and newer targeted agents, even the most newly developed, immune-based therapeutic modalities of anticancer treatment (the fifth modality), e.g., immune checkpoint inhibitors and chimeric antigen receptor (CAR) T-cell therapy, have unfortunately led to potentially lethal cardiotoxicity in patients. Cardiac complications represent unresolved and potentially life-threatening conditions in cancer survivors, while effective clinical management remains quite challenging. As a consequence, morbidity and mortality related to cardiac complications now threaten to offset some favorable benefits of modern cancer treatments in cancer-related survival, regardless of the oncologic prognosis. This review focuses on identifying critical research-practice gaps, addressing real-world challenges and pinpointing real-time insights in general terms under the context of clinical cardiotoxicity induced by the fourth and fifth modalities of cancer treatment. The information ranges from basic science to clinical management in the field of cardio-oncology and crosses the interface between oncology and onco-pharmacology. The complexity of the ongoing clinical problem is addressed at different levels. A better understanding of these research-practice gaps may advance research initiatives on the development of mechanism-based diagnoses and treatments for the effective clinical management of cardiotoxicity.

Antigen presentation of the Oct4 and Sox2 peptides by CD154-activated B lymphocytes enhances the killing effect of cytotoxic T lymphocytes on tumor stem-like cells derived from cisplatin-resistant lung cancer cells

The present study investigated whether antigen presentation of the Oct4 and Sox2 peptides by CD154-activated B lymphocytes can enhance the killing effect of CD8⁺ cytotoxic T lymphocytes (CTLs) on lung stem-like cancer cells (SLCCs). The CTLs were generated using an accelerated co-cultured dendritic cells (DC) (acDC) assay by incubating human peripheral blood mononuclear cells (PBMCs) from non-small-cell lung cancer patients with antigen peptides of Oct4 and Sox2 in the presence of several DC-activating agents. CD154⁺ NIH3T3 cells prepared by CD154 lentiviral transfection were used as feeder layer to activate primary B cells (CD19⁺) obtained from PBMCs. Activated B cells were co-cultured with CTLs to present antigen peptides of Oct4 and Sox2. CTLs co-cultured with activated B cells were evaluated for the levels of secreted inflammatory cytokines using ELISA. In addition, the killing effect of the CTLs on SLCCs derived from cisplatin-resistant strain of human lung cancer cell line PC9 was evaluated by flow cytometry using CFSE labeling of the target cells. After the acDC assay, the PBMCs exhibited a significant (p<0.01) increase in the population of CD8⁺/CD3⁺ cells, indicating successful preparation of CTLs. The primary B cells cultured on the CD154⁺ NIH3T3 feeder layer resulted in significant (p<0.01) increase in the proportions of population expressing CD80, CD86, or HLA-A, indicating successful activation of the B cells. The co-culture of CTLs with CD154-activated B cells presenting the Oct4 and Sox2 peptides caused significant increase in the levels of secretory inflammatory cytokines and exhibited enhanced killing of the SLCCs derived from cisplatin-resistant PC9 cells. Antigen presentation of the Oct4 and Sox2 peptides by CD154-activated B cells can enhance the killing effect of CTLs towards lung SLCCs.

B7-H3 as a promising target for cytotoxicity T cell in human cancer therapy

Targeting B7-H3 over-expressed tumor cells with anti-B7-H3 monoclonal antibodies inhibits tumor growth. Here we demonstrated the expression of B7 family homologue 3 (B7-H3) in a wide range of human tumor cells and further investigated whether B7-H3 could be served as a target for T-cell mediated immunotherapy against human cancers. The specific cytotoxic activity of activated T cell (ATC) armed with a novel anti-CD3 x anti-B7-H3 bispecific antibody (B7-H3Bi-Ab) against tumor cell was evaluated in vitro and in vivo. In contrast with unarmed ATC, an increase in cytotoxic activity of B7-H3Bi-armed ATC against tumor cells was observed at effector/target (E/T) ratios of 5:1, 10:1, and 20:1. Moreover, B7-H3Bi-armed ATC secreted more IFN-γ, TNF-α and IL-2 than unarmed ATC. Infusion of B7-H3Bi-armed ATC inhibited tumor growth in severe combined immunodeficiency (SCID) xenograft models, along with a significant survival benefit. Therefore, treatment with novel B7-H3Bi-armed ATC will be a promising strategy for current cancer immunotherapy.

Chimeric Antigen Receptor-Engineered Human Gamma Delta T Cells: Enhanced Cytotoxicity with Retention of Cross Presentation

Gamma delta T (γδT) lymphocytes are primed for rapid function, including cytotoxicity toward cancer cells, and are a component of the immediate stress response. Following activation, they can function as professional antigen-presenting cells. Chimeric antigen receptors (CARs) work by focusing T cell function on defined cell surface tumor antigens and provide essential costimulation for robust activation. Given the natural tropism of γδT cells for the tumor microenvironment, we hypothesized that their transduction with CARs might enhance cytotoxicity while retaining their ability to migrate to tumor and act as antigen-presenting cells to prolong the intratumoral immune response. Using a GD2-targeting CAR as a model system, we showed that γδT cells of both Vδ1 and Vδ2 subsets could be expanded and transduced to sufficient numbers for clinical studies. The CAR added to the cells' innate cytotoxicity by enhancing GD2-specific killing of GD2-expressing cancer cell lines. Migration toward tumor cells in vitro was not impaired by the presence of the CAR. Expanded CAR-transduced Vδ2 cells retained the ability to take up tumor antigens and cross presented the processed peptide to responder alpha beta T (αβT) lymphocytes. γδ CAR-T cell products show promise for evaluation in clinical studies of solid tumors.

How immunotherapies are targeting the glioblastoma immune environment

The diagnosis of glioblastoma remains one of the most dismal in medical practice, with current standard care only providing a median survival of 14.6 months. The need for new therapies is desperately clear. Components of the tumour microenvironment are demonstrating growing importance in the field, given they allow the tumour to utilise pathways involved in autoimmune prevention, something that enables the tumour's establishment and growth. As with many different cancers, the search for a new standard has progressed to the design of immunotherapies, which aim to counteract the immune changes within this microenvironment. Serotherapy, adoptive lymphocyte transfer, peptide and dendritic cell vaccines and a range of other methods are currently under investigation, while intracranial infection has also been researched for its capacity to reverse glioblastoma mediated immunosuppression. Some of these new therapies have shown promise, but it is a long road ahead before their incorporation into glioblastoma standard therapy.

Current status and future prospects for human papillomavirus vaccines

Cervical cancer is the fourth most frequent cancer among women worldwide. Human papillomaviruses (HPVs) cause almost all cervical cancers in low-income countries. Three prophylactic HPV virus-like particle-based vaccines have been licensed to date, and they have all shown high efficacy and reliable safety profiles. However, isolated safety issues have resulted in a reluctance to use these vaccinations. In addition, the high prices of the vaccinations have caused the inequitable distribution of the vaccine: the prices are unaffordable for low-income countries. Meanwhile, great effort has been put into the development of therapeutic HPV vaccines, including protein/peptide-, live vector-, DNA- and cell-based vaccines. These new vaccines have considerable therapeutic potential but limited practical use. The development of immune checkpoint inhibitors and personalized immunotherapy remain challenges for future study. In this article, the current status of the licensed vaccines, therapeutic HPV vaccines and biosimilars, and new platforms for HPV vaccines, are reviewed, and safety issues related to the licensed vaccines are discussed. In addition, the prospects for HPV vaccines are considered.

Engineering macrophages to eat cancer: from "marker of self" CD47 and phagocytosis to differentiation

The ability of a macrophage to engulf and break down invading cells and other targets provides a first line of immune defense in nearly all tissues. This defining ability to "phagos" or devour can subsequently activate the entire immune system against foreign and diseased cells, and progress is now being made on a decades-old idea of directing macrophages to phagocytose specific targets, such as cancer cells. Engineered T cells provide precedence with recent clinical successes against liquid tumors, but solid tumors remain a challenge, and a handful of clinical trials seek to exploit the abundance of tumor-associated macrophages instead. Although macrophage differentiation into such phenotypes with deficiencies in phagocytic ability can raise challenges, newly recognized features of cancer cells that might be manipulated to increase the phagocytosis of those cells include ≥1 membrane protein, CD47, which broadly inhibits phagocytosis and is abundantly expressed on all healthy cells. Physical properties of the target also influence phagocytosis and again relate-via cytoskeleton forces-to differentiation pathways in solid tumors. Such pathways extend to mechanosensing by the nuclear lamina, which is known to influence signaling by soluble retinoids that can regulate the macrophage SIRPα, the receptor for CD47. Here, we highlight some of those past, present, and rapidly emerging efforts to understand and control macrophages for cancer therapy.

[Adoptive transfer of T lymphocytes]

Within a few years, the success of treatments based on the use of T-cells armed with a chimeric T-receptor for the CD19 molecule (CAR-T CD19) has revolutionized the perception of adoptive transfer approaches. The levels of responses observed in acute leukemias, of the order of 70-90 % are indeed unprecedented. The medical and financial enthusiasm aroused by these results has led to the current situation where more than 300 clinical trials are under way, against some thirty different antigens. This enthusiasm, well justified by the first successes, must however be tempered by the difficulties associated with the use of these cells. Indeed, the management of patients is made very complex both for medical reasons, because the toxicities associated with these treatments are important, and for technical reasons, because the preparation of T lymphocytes for therapeutic use requires dedicated structures. During this same period, knowledge of the mechanisms of regulation of T lymphocytes and the possibilities offered by synthetic biology and techniques of genome engineering have progressed considerably. Combined, they allow envisaging a true "programming" of the T lymphocytes, intended to improve the efficiency of the treatments and the safety of the patients. Medical and industrial perspectives and the role of these approaches in the arsenal of cancer therapies will depend largely on two conditions: the emergence of a robust demonstration of their effectiveness in solid tumors, and the establishment of an acceptable production and distribution model 1.

Exploiting natural killer group 2D receptors for CAR T-cell therapy

Chimeric antigen receptors (CARs) are genetically engineered proteins that combine an extracellular antigen-specific recognition domain with one or several intracellular T-cell signaling domains. When expressed in T cells, these CARs specifically trigger T-cell activation upon antigen recognition. While the clinical proof of principle of CAR T-cell therapy has been established in hematological cancers, CAR T cells are only at the early stages of being explored to tackle solid cancers. This special report discusses the concept of exploiting natural killer cell receptors as an approach that could broaden the specificity of CAR T cells and potentially enhance the efficacy of this therapy against solid tumors. New data demonstrating feasibility of this approach in humans and supporting the ongoing clinical trial are also presented.