Adoptive T cell therapy: points to consider

Ammonia-induced lysosomal and mitochondrial damage causes cell death of effector CD8+ T cells

Ammonia is thought to be a cytotoxin and its increase in the blood impairs cell function. However, whether and how this toxin triggers cell death under pathophysiological conditions remains unclear. Here we show that ammonia induces a distinct form of cell death in effector T cells. We found that rapidly proliferating T cells use glutaminolysis to release ammonia in the mitochondria, which is then translocated to and stored in the lysosomes. Excessive ammonia accumulation increases lysosomal pH and results in the termination of lysosomal ammonia storage and ammonia reflux into mitochondria, leading to mitochondrial damage and cell death, which is characterized by lysosomal alkalization, mitochondrial swelling and impaired autophagic flux. Inhibition of glutaminolysis or blocking lysosomal alkalization prevents ammonia-induced T cell death and improves T cell-based antitumour immunotherapy. These findings identify a distinct form of cell death that differs from previously known mechanisms.

A strategy to reconstitute immunity without GVHD via adoptive allogeneic Tscm therapy

Introduction

Adoption of allogeneic T cells directly supplements the number of T cells and rapidly induces T-cell immunity, which has good efficacy for treating some tumors and immunodeficiency diseases. However, poor adoptive T-cell engraftment and graft-versus-host disease (GVHD) limit the application of these methods. Alloreactive T-cell clones were eliminated from the donor T-cell repertoire, and the remaining T-cell clones were prepared as Tscm for T-cell adoptive treatment to reconstruct recipient T-cell immunity without GVHD.

Methods

The subjects in this study included three different strains of mice. Lymphocytes from mice (C57BL/6) were used as the donor T-cell repertoire, from which the Tscm allo-reactive T cell clone was depleted (ATD-Tscm). This was confirmed by showing that the Tscm was not responsive to the alloantigen of the recipient (BALB/c). To prepare ATD-Tscm cells, we used recipient lymphocytes as a simulator, and coculture of mouse and recipient lymphocytes was carried out for 7 days. Sorting of non-proliferative cells ensured that the prepared Tscm cells were nonresponsive. The sorted lymphocytes underwent further expansion by treatment with TWS119 and cytokines for an additional 10 days, after which the number of ATD-Tscm cells increased. The prepared Tscm cells were transferred into recipient mice to observe immune reconstitution and GVHD incidence.

Results

Our protocol began with the use of 1×107 donor lymphocytes and resulted in 1 ×107 ATD-Tscm cells after 17 days of preparation. The prepared ATD-Tscm cells exhibited a nonresponse upon restimulation of the recipient lymphocytes. Importantly, the prepared ATD-Tscm cells were able to bind long and reconstitute other T-cell subsets in vivo, effectively recognizing and answering the "foreign" antigen without causing GVHD after they were transferred into the recipients.

Discussion

Our strategy was succeeded to prepare ATD-Tscm cells from the donor T-cell repertoire. The prepared ATD-Tscm cells were able to reconstitute the immune system and prevent GVHD after transferred to the recipients. This study provides a good reference for generating ATD-Tscm for T-cell adoptive immunotherapy.

Enhancing antitumor response by efficiently generating large-scale TCR-T cells targeting a single epitope across multiple cancer antigens

The need to contrive interventions to curb the rise in cancer incidence and mortality is critical for improving patients' prognoses. Adoptive cell therapy is challenged with quality large-scale production, heightening its production cost. Several cancer types have been associated with the expression of highly-immunogenic CTAG1 and CTAG2 antigens, which share common epitopes. Targeting two antigens on the same cancer could improve the antitumor response of TCR-T cells. In this study, we exploited an efficient way to generate large-fold quality TCR-T cells and also demonstrated that the common epitopes of CTAG1 and CTAG2 antigens provide an avenue for improved cancer-killing via dual-antigen-epitope targeting. Our study revealed that xeno/sera-free medium could expand TCR-T cells to over 500-fold, posing as a better replacement for FBS-supplemented media. Human AB serum was also shown to be a good alternative in the absence of xeno/sera-free media. Furthermore, TCR-T cells stimulated with beads-coated T-activator showed a better effector function than soluble T-activator stimulated TCR-T cells. Additionally, TCR-T cells that target multiple antigens in the same cancer yield better anticancer activity than those targeting a single antigen. This showed that targeting multiple antigens with a common epitope may enhance the antitumor response efficacy of T cell therapies.

Novel insights into TCR-T cell therapy in solid neoplasms: optimizing adoptive immunotherapy

Adoptive immunotherapy in the T cell landscape exhibits efficacy in cancer treatment. Over the past few decades, genetically modified T cells, particularly chimeric antigen receptor T cells, have enabled remarkable strides in the treatment of hematological malignancies. Besides, extensive exploration of multiple antigens for the treatment of solid tumors has led to clinical interest in the potential of T cells expressing the engineered T cell receptor (TCR). TCR-T cells possess the capacity to recognize intracellular antigen families and maintain the intrinsic properties of TCRs in terms of affinity to target epitopes and signal transduction. Recent research has provided critical insight into their capability and therapeutic targets for multiple refractory solid tumors, but also exposes some challenges for durable efficacy. In this review, we describe the screening and identification of available tumor antigens, and the acquisition and optimization of TCRs for TCR-T cell therapy. Furthermore, we summarize the complete flow from  laboratory to clinical applications of TCR-T cells. Last, we emerge future prospects for improving therapeutic efficacy in cancer world with combination therapies or TCR-T derived products. In conclusion, this review depicts our current understanding of TCR-T cell therapy in solid neoplasms, and provides new perspectives for expanding its clinical applications and improving therapeutic efficacy.

Boosting immune responses in lung tumor immune microenvironment: A comprehensive review of strategies and adjuvants

The immune system has a substantial impact on the growth and expansion of lung malignancies. Immune cells are encompassed by a stroma comprising an extracellular matrix (ECM) and different cells like stromal cells, which are known as the tumor immune microenvironment (TIME). TME is marked by the presence of immunosuppressive factors, which inhibit the function of immune cells and expand tumor growth. In recent years, numerous strategies and adjuvants have been developed to extend immune responses in the TIME, to improve the efficacy of immunotherapy. In this comprehensive review, we outline the present knowledge of immune evasion mechanisms in lung TIME, explain the biology of immune cells and diverse effectors on these components, and discuss various approaches for overcoming suppressive barriers. We highlight the potential of novel adjuvants, including toll-like receptor (TLR) agonists, cytokines, phytochemicals, nanocarriers, and oncolytic viruses, for enhancing immune responses in the TME. Ultimately, we provide a summary of ongoing clinical trials investigating these strategies and adjuvants in lung cancer patients. This review also provides a broad overview of the current state-of-the-art in boosting immune responses in the TIME and highlights the potential of these approaches for improving outcomes in lung cancer patients.

A phase I dose-escalation study of neoantigen-activated haploidentical T cell therapy for the treatment of relapsed or refractory peripheral T-cell lymphoma

Peripheral T-cell lymphoma (PTCL) is a type of highly heterogeneous non-Hodgkin lymphoma with a poor prognosis and lack of effective targeted therapies. Adoptive T-cell therapy has been successfully used in the treatment of B-cell malignancies. We first used adoptive transfer of haploidentical T cells activated by patient-specific neoantigens in vitro to treat an elderly patient with refractory angioimmunoblastic T-cell lymphoma (AITL) in 2017, and the patient achieved long-term complete remission (CR). Here we report on early results from this first-in-human phase 1 clinical trial that aims to assess the safety and tolerability of neoantigen-activated haploidentical T cell therapy (NAHTC) for relapsed/refractory PTCL.

CLINICAL TRIAL REGISTRATION

http://www.chictr.org.cn/index.aspx, identifier [ChiCTR1800017440].

Enhanced development of functional human NK cells in NOD-scid-IL2rgnull mice expressing human IL15

Human innate immunity plays a critical role in tumor surveillance and in immunoregulation within the tumor microenvironment. Natural killer (NK) cells are innate lymphoid cells that have opposing roles in the tumor microenvironment, including NK cell subsets that mediate tumor cell cytotoxicity and subsets with regulatory function that contribute to the tumor immune suppressive environment. The balance between effector and regulatory NK cell subsets has been studied extensively in murine models of cancer, but there is a paucity of models to study human NK cell function in tumorigenesis. Humanized mice are a powerful alternative to syngeneic mouse tumor models for the study of human immuno-oncology and have proven effective tools to test immunotherapies targeting T cells. However, human NK cell development and survival in humanized NOD-scid-IL2rg^null (NSG) mice are severely limited. To enhance NK cell development, we have developed NSG mice that constitutively expresses human Interleukin 15 (IL15), NSG-Tg(Hu-IL15). Following hematopoietic stem cell engraftment of NSG-Tg(Hu-IL15) mice, significantly higher levels of functional human CD56+ NK cells are detectable in blood and spleen, as compared to NSG mice. Hematopoietic stem cell (HSC)-engrafted NSG-Tg(Hu-IL15) mice also supported the development of human CD3+ T cells, CD20+ B cells, and CD33+ myeloid cells. Moreover, the growth kinetics of a patient-derived xenograft (PDX) melanoma were significantly delayed in HSC-engrafted NSG-Tg(Hu-IL15) mice as compared to HSC-engrafted NSG mice demonstrating that human NK cells have a key role in limiting the tumor growth. Together, these data demonstrate that HSC-engrafted NSG-Tg(Hu-IL15) mice support enhanced development of functional human NK cells, which limit the growth of PDX tumors.

Finding the right help in the tumor microenvironment

Tumor-infiltrating lymphocytes (TILs) contain substantial numbers of CD4+ T cells mediating pro- and antitumor functions. While CD4+ Tregs are well characterized and known to promote tumor immune evasion, the fingerprint of CD4+ Th cells that recognizes tumor antigens and serves to restrict disease progression has remained poorly discriminated. In this issue of the JCI, Duhen et al. analyzed tumors from patients with head and neck squamous cell carcinoma or colon carcinoma and identified a unique programmed cell death 1-positive, ICOS1-positive (PD-1+ICOS1+) subpopulation of CD4+ TILs highly enriched for the ability to recognize tumor-associated antigens. These cells localized proximally to MHC II+ antigen-presenting cells and CD8+ T cells within tumors, where they appeared to proliferate and function almost exclusively as Th cells. These potentially therapeutic Th cells can be monitored for patient prognosis and are expected to have substantial utility in developing personalized adoptive cell- and vaccine-based immunotherapeutic approaches for improving patient outcomes.

Neo-Splicetopes in Tumor Therapy: A Lost Case?

Proteasome generates spliced peptides by ligating two distant cleavage products in a reverse proteolysis reaction. The observation that CD8+ T cells recognizing a spliced peptide induced T cell rejection in a melanoma patient following adoptive T cell transfer (ATT), raised some hopes with regard to the general therapeutic and immune relevance of spliced peptides. Concomitantly, the identification of spliced peptides was also the start of a controversy with respect to their frequency, abundancy and their therapeutic applicability. Here I review some of the recent evidence favoring or disfavoring an immune relevance of splicetopes and discuss from a theoretical point of view the potential usefulness of tumor specific splicetopes and why against all odds it still may seem worth trying to identify such tumor and patient-specific neosplicetopes for application in ATT.

Injectable Diels-Alder cycloaddition hydrogels with tuneable gelation, stiffness and degradation for the sustained release of T-lymphocytes

Engineered T-cell therapies have proven highly efficacious for the treatment of haematological cancers, but translation of this success to solid tumours has been limited, in part, due to difficulties in maintaining high doses at specific target sites. Hydrogel delivery systems that provide a sustained release of T-cells at the target site are emerging as a promising strategy. Therefore, in this study we aimed to develop an injectable hydrogel that gels in situ via efficient Diels-Alder cycloaddition (DAC) chemistry and provides a sustained release of T-cells through gradual hydrolysis of the hydrogel matrix. Hydrogels were prepared via the DAC between fulvene and maleimide functionalised poly(ethylene glycol) (PEG) derivatives. By adjusting the concentration and molecular weight of the functionalised PEGs in the hydrogel formulation the in vitro gelation time (T_gel), initial Young's modulus (E) and degradation time (T_d) could be tailored from 15-150 min, 5-179 kPa and 7-114 h, respectively. Prior to gelation, the formulations could be readily injected through narrow gauge (26 G) needles with the working time correlating closely with the T_gel. A 5 wt% hydrogel formation with conjugated cyclic RGD motif was found to be optimal for the encapsulation and release of CD3⁺ T-cells with a near linear release profile and >70% cell viability over the first 4 d and release continuing out to 7 d. With their tuneable T_gel, T_d and stiffness, the DAC hydrogels provide the opportunity to control the release period and profile of encapsulated cells.

Adoptive immunotherapy with transient anti-CD4 treatment enhances anti-tumor response by increasing IL-18Rαhi CD8+ T cells

Adoptive T cell therapy (ACT) requires lymphodepletion preconditioning to eliminate immune-suppressive elements and enable efficient engraftment of adoptively transferred tumor-reactive T cells. As anti-CD4 monoclonal antibody depletes CD4⁺ immune-suppressive cells, the combination of anti-CD4 treatment and ACT has synergistic potential in cancer therapy. Here, we demonstrate a post-ACT conditioning regimen that involves transient anti-CD4 treatment (CD4^post). Using murine melanoma, the combined effect of cyclophosphamide preconditioning (CTX^pre), CD4^post, and ex vivo primed tumor-reactive CD8⁺ T-cell infusion is presented. CTX^pre/CD4^post increases tumor suppression and host survival by accelerating the proliferation and differentiation of ex vivo primed CD8⁺ T cells and endogenous CD8⁺ T cells. Endogenous CD8⁺ T cells enhance effector profile and tumor-reactivity, indicating skewing of the TCR repertoire. Notably, enrichment of polyfunctional IL-18Rα^hi CD8⁺ T cell subset is the key event in CTX^pre/CD4^post-induced tumor suppression. Mechanistically, the anti-tumor effect of IL-18Rα^hi subset is mediated by IL-18 signaling and TCR–MHC I interaction. This study highlights the clinical relevance of CD4^post in ACT and provides insights regarding the immunological nature of anti-CD4 treatment, which enhances anti-tumor response of CD8⁺ T cells.

Lymphodepleting preconditioning is generally required prior to adoptive T cell therapy (ACT). Here the authors show in a preclinical melanoma model that anti-CD4 treatment as a post-conditioning regimen enhances the anti-tumor efficacy of ACT by promoting the expansion of IL-18Rα^hi CD8⁺ T cells.

Engineering Nano-Therapeutics to Boost Adoptive Cell Therapy for Cancer Treatment

Although adoptive transfer of therapeutic cells to cancer patients is demonstrated with great success and fortunately approved for the treatment of leukemia and B-cell lymphoma, potential issues, including the unclear mechanism, complicated procedures, unfavorable therapeutic efficacy for solid tumors, and side effects, still hinder its extensive applications. The explosion of nanotechnology recently has led to advanced development of novel strategies to address these challenges, facilitating the design of nano-therapeutics to improve adoptive cell therapy (ACT) for cancer treatment. In this review, the emerging nano-enabled approaches, that design multiscale artificial antigen-presenting cells for cell proliferation and stimulation in vitro, promote the transducing efficiency of tumor-targeting domains, engineer therapeutic cells for in vivo imaging, tumor infiltration, and in vivo functional sustainability, as well as generate tumoricidal T cells in vivo, are summarized. Meanwhile, the current challenges and future perspectives of the nanostrategy-based ACT for cancer treatment are also discussed in the end.

Target Reprogramming Lysosomes of CD8+ T Cells by a Mineralized Metal-Organic Framework for Cancer Immunotherapy

T cell immunotherapy holds significant challenges in solid tumors, mainly due to the T cells' low activation and the decreased synthesis-release of therapeutic proteins, including perforin and granzyme B, which are present in lysosomes. In this study, a lysosome-targeting nanoparticle (LYS-NP) is developed by way of a mineralized metal-organic framework (MOF) coupled with a lysosome-targeting aptamer (CD63-aptamer) to enhance the antitumor effect of T cells. The MOF synthesized from Zn2+ and dimethylimidazole has good protein encapsulation and acid sensitivity, and is thus an ideal lysosomal delivery vector. Calcium carbonate (CaCO3 ) is used to induce MOF mineralization, improve the composite material's stability in encapsulating therapeutic protein, and provide calcium ions with synergistic effects. Before mineralization, perforin and granzyme B-T cell-needed therapeutic proteins for tumors-are preloaded with the MOF. Moreover, T cells are pretreated with processed tumor-specific antigens to activate or produce memory before reprogramming the lysosomes, facilitating the T cell receptor (TCR) for release of the therapeutic proteins. Using T cells recombined by LYS-NPs, a significant enhancement of breast cancer control is confirmed.

Engineering Metabolism of Chimeric Antigen Receptor (CAR) Cells for Developing Efficient Immunotherapies

Chimeric antigen receptor (CAR) T cell-based therapies have shown tremendous advancement in clinical and pre-clinical studies for the treatment of hematological malignancies, such as the refractory of pre-B cell acute lymphoblastic leukemia (B-ALL), chronic lymphocytic leukemia (CLL), and large B cell lymphoma (LBCL). However, CAR T cell therapy for solid tumors has not been successful clinically. Although, some research efforts, such as combining CARs with immune checkpoint inhibitor-based therapy, have been used to expand the application of CAR T cells for the treatment of solid tumors. Importantly, further understanding of the coordination of nutrient and energy supplies needed for CAR T cell expansion and function, especially in the tumor microenvironment (TME), is greatly needed. In addition to CAR T cells, there is great interest in utilizing other types of CAR immune cells, such as CAR NK and CAR macrophages that can infiltrate solid tumors. However, the metabolic competition in the TME between cancer cells and immune cells remains a challenge. Bioengineering technologies, such as metabolic engineering, can make a substantial contribution when developing CAR cells to have an ability to overcome nutrient-paucity in the solid TME. This review introduces technologies that have been used to generate metabolically fit CAR-immune cells as a treatment for hematological malignancies and solid tumors, and briefly discusses the challenges to treat solid tumors with CAR-immune cells.

Synthetic TILs: Engineered Tumor-Infiltrating Lymphocytes With Improved Therapeutic Potential

Immunotherapy has emerged as an effective and life-changing approach for several types of cancers, both liquid and solid tumors. In combination with traditional treatments such as radiotherapy and/or chemotherapy, immune checkpoints inhibitors have improved prognosis and overall survival of patients with advanced melanoma and many other cancers. Among adoptive cell therapies (ACT), while chimeric antigen receptor T cell therapies have demonstrated remarkable efficacy in some hematologic malignancies, such as B cell leukemias, their success in solid tumors remains scarce due to the characteristics of the tumor microenvironment. On the other hand, ACT using tumor-infiltrating lymphocytes (TILs) is arguably the most effective treatment for metastatic melanoma patients, but even if their isolation has been achieved in epithelial tumors, their success beyond melanoma remains limited. Here, we review several aspects impacting TIL- and gene-modified “synthetic” TIL-based therapies and discuss future challenges that must be addressed with these approaches.

Neospora caninum: a new class of biopharmaceuticals in the therapeutic arsenal against cancer

BACKGROUND

Microorganisms that can be used for their lytic activity against tumor cells as well as inducing or reactivating antitumor immune responses are a relevant part of the available immunotherapy strategies. Viruses, bacteria and even protozoa have been largely explored with success as effective human antitumor agents. To date, only one oncolytic virus-T-VEC-has been approved by the US Food and Drug Administration for use in biological cancer therapy in clinical trials. The goal of our study is to evaluate the potential of a livestock pathogen, the protozoan Neospora caninum, non-pathogenic in humans, as an effective and safe antitumorous agent.

METHODS/RESULTS

We demonstrated that the treatment of murine thymoma EG7 by subcutaneous injection of N. caninum tachyzoites either in or remotely from the tumor strongly inhibits tumor development, and often causes their complete eradication. Analysis of immune responses showed that N. caninum had the ability to 1) lyze infected cancer cells, 2) reactivate the immunosuppressed immune cells and 3) activate the systemic immune system by generating a protective antitumor response dependent on natural killer cells, CD8-T cells and associated with a strong interferon (IFN)-γ secretion in the tumor microenvironment. Most importantly, we observed a total clearance of the injected agent in the treated animals: N. caninum exhibited strong anticancer effects without persisting in the organism of treated mice. We also established in vitro and an in vivo non-obese diabetic/severe combined immunodeficiency mouse model that N. caninum infected and induced a strong regression of human Merkel cell carcinoma. Finally, we engineered a N. caninum strain to secrete human interleukin (IL)-15, associated with the alpha-subunit of the IL-15 receptor thus strengthening the immuno-stimulatory properties of N. caninum. Indeed, this NC1-IL15hRec strain induced both proliferation of and IFN-γ secretion by human peripheral blood mononuclear cells, as well as improved efficacy in vivo in the EG7 tumor model.

CONCLUSION

These results highlight N. caninum as a potential, extremely effective and non-toxic anticancer agent, capable of being engineered to either express at its surface or to secrete biodrugs. Our work has identified the broad clinical possibilities of using N. caninum as an oncolytic protozoan in human medicine.

Nanomedicines modulating tumor immunosuppressive cells to enhance cancer immunotherapy

Cancer immunotherapy has veered the paradigm of cancer treatment. Despite recent advances in immunotherapy for improved antitumor efficacy, the complicated tumor microenvironment (TME) is highly immunosuppressive, yielding both astounding and unsatisfactory clinical successes. In this regard, clinical outcomes of currently available immunotherapy are confined to the varied immune systems owing in large part to the lack of understanding of the complexity and diversity of the immune context of the TME. Various advanced designs of nanomedicines could still not fully surmount the delivery barriers of the TME. The immunosuppressive TME may even dampen the efficacy of antitumor immunity. Recently, some nanotechnology-related strategies have been inaugurated to modulate the immunosuppressive cells within the tumor immune microenvironment (TIME) for robust immunotherapeutic responses. In this review, we will highlight the current understanding of the immunosuppressive TIME and identify disparate subclasses of TIME that possess an impact on immunotherapy, especially those unique classes associated with the immunosuppressive effect. The immunoregulatory cell types inside the immunosuppressive TIME will be delineated along with the existing and potential approaches for immunosuppressive cell modulation. After introducing the various strategies, we will ultimately outline both the novel therapeutic targets and the potential issues that affect the efficacy of TIME-based nanomedicines.

T-Cell-Mimicking Nanoparticles for Cancer Immunotherapy

Cancer immunotherapies, including adoptive T cell transfer and immune checkpoint blockades, have recently shown considerable success in cancer treatment. Nevertheless, transferred T cells often become exhausted because of the immunosuppressive tumor microenvironment. Immune checkpoint blockades, in contrast, can reinvigorate the exhausted T cells; however, the therapeutic efficacy is modest in 70-80% of patients. To address some of the challenges faced by the current cancer treatments, here T-cell-membrane-coated nanoparticles (TCMNPs) are developed for cancer immunotherapy. Similar to cytotoxic T cells, TCMNPs can be targeted at tumors via T-cell-membrane-originated proteins and kill cancer cells by releasing anticancer molecules and inducing Fas-ligand-mediated apoptosis. Unlike cytotoxic T cells, TCMNPs are resistant to immunosuppressive molecules (e.g., transforming growth factor-β1 (TGF-β1)) and programmed death-ligand 1 (PD-L1) of cancer cells by scavenging TGF-β1 and PD-L1. Indeed, TCMNPs exhibit higher therapeutic efficacy than an immune checkpoint blockade in melanoma treatment. Furthermore, the anti-tumoral actions of TCMNPs are also demonstrated in the treatment of lung cancer in an antigen-nonspecific manner. Taken together, TCMNPs have a potential to improve the current cancer immunotherapy.

Novel cellular immunotherapy using NKG2D CAR-T for the treatment of cervical cancer

Cellular immunotherapy, including chimeric antigen receptor (CAR) modified T cell therapy, has been regarded as one of the most potential antineoplastic drugs for hematological malignancies and solid tumor. However, due to lacking the suitable target, there is no CAR-T drug had been appoved by FDA for the treatment of cervical cancer, one of the most malignant cancers for women. In current study, we designed a NKG2D CAR-T targeting NKG2DL. The NKG2D CAR-T exhibited high-efficient anti-tumor capacity for NKG2DL positive cervical cancer cell line in vitro. In addition, the amount of cytokines secreted from CAR-T cells have had significantly enhanced after co-cultured with NKG2DL positive tumor cell in vitro. In vivo, NKG2D CAR-T cells presented a robust capacity of significantly suppressing tumor growth. Moreover, there was no obvious off-target toxicity after NKG2D CAR-T infusion. Taken together, NKG2D CAR-T showed excellent therapy effect for cervical cancer and might be used as a novel cellular therapeutic agent for treating cervical cancer.

Dual-function chimeric antigen receptor T cells targeting c-Met and PD-1 exhibit potent anti-tumor efficacy in solid tumors

Purpose Programmed cell death 1 (PD-1), which is upregulated under the continuous induction of the tumor microenvironment, causes chimeric antigen receptor (CAR)-T cell hypofunction via interaction with programmed death ligand 1 (PD-L1). This study aimed to construct CAR-T cells that are resistant to PD-1 inhibition to improve the effect of CAR-T cells in solid tumors. Methods We constructed a type of dual-function CAR-T cell that targets tumor-associated antigen c-Met and blocks the binding of PD-1 with PD-L1. The expression of c-Met, PD-L1, and inhibitory receptors was measured using flow cytometry. The cytotoxicity, cytokine release, and differentiation level of CAR-T cells were determined using lactate dehydrogenase release assay, enzyme-linked immunosorbent assay, and flow cytometry, respectively. The levels of p-Akt, p-MAPK, caspase-3, and Bcl2 were detected by western blot. The in vivo anti-tumor effect was evaluated using tumor xenograft models. Results Dual-function CAR-T cells could mediate enhanced active signals upon encountering target antigens and had targeted cytotoxicity to target cells. However, the cytotoxicity of c-Met-CAR-PD-1⁺ T cells was impaired due to the interaction of PD-1 with PD-L1. By blocking the binding of PD-1 and PD-L1, the novel dual-function CAR-PD-1⁺ T cells could maintain cytotoxicity to PD-L1⁺ tumor cells. In tumor tissue, the dual-function CAR-T cells showed lower inhibitory receptor expression and lower differentiation characteristics, which resulted in potent anti-tumor effects and prolonged survival in PD-L1⁺ tumor xenograft models compared to single-target CAR-T cells. Conclusion These results confirm that the novel dual-function CAR-T cells exhibit stronger anti-tumor activity against solid tumors than traditional single-target CAR-T cells and present a new approach that enhance the activity of CAR-T cells in solid tumors.

The Possibilities of Immunotherapy for Children with Primary Immunodeficiencies Associated with Cancers

Many primary immunodeficiencies (PIDs) are recognised as being associated with malignancies, particularly lymphoid malignancies, which represent the highest proportion of cancers occurring in conjunction with this underlying condition. When patients present with genetic errors of immunity, clinicians must often reflect on whether to manage antitumoral treatment conventionally or to take a more personalised approach, considering possible existing comorbidities and the underlying status of immunodeficiency. Recent advances in antitumoral immunotherapies, such as monoclonal antibodies, antigen-specific adoptive cell therapies or compounds with targeted effects, potentially offer significant opportunities for optimising treatment for those patients, especially with lymphoid malignancies. In cases involving PIDs, variable oncogenic mechanisms exist, and opportunities for antitumoral immunotherapies can be considered accordingly. In cases involving a DNA repair defect or genetic instability, monoclonal antibodies can be proposed instead of chemotherapy to avoid severe toxicity. Malignancies secondary to uncontrolled virus-driven proliferation or the loss of antitumoral immunosurveillance may benefit from antivirus cell therapies or allogeneic stem cell transplantation in order to restore the immune antitumoral caretaker function. A subset of PIDs is caused by gene defects affecting targetable signalling pathways directly involved in the oncogenic process, such as the constitutive activation of phosphoinositol 3-kinase/protein kinase B (PI3K/AKT) in activated phosphoinositide 3-kinase delta syndrome (APDS), which can be settled with PI3K/AKT inhibitors. Therefore, immunotherapy provides clinicians with interesting antitumoral therapeutic weapons to treat malignancies when there is an underlying PID.

Ultrasound-Responsive Cavitation Nuclei for Therapy and Drug Delivery

Therapeutic ultrasound strategies that harness the mechanical activity of cavitation nuclei for beneficial tissue bio-effects are actively under development. The mechanical oscillations of circulating microbubbles, the most widely investigated cavitation nuclei, which may also encapsulate or shield a therapeutic agent in the bloodstream, trigger and promote localized uptake. Oscillating microbubbles can create stresses either on nearby tissue or in surrounding fluid to enhance drug penetration and efficacy in the brain, spinal cord, vasculature, immune system, biofilm or tumors. This review summarizes recent investigations that have elucidated interactions of ultrasound and cavitation nuclei with cells, the treatment of tumors, immunotherapy, the blood-brain and blood-spinal cord barriers, sonothrombolysis, cardiovascular drug delivery and sonobactericide. In particular, an overview of salient ultrasound features, drug delivery vehicles, therapeutic transport routes and pre-clinical and clinical studies is provided. Successful implementation of ultrasound and cavitation nuclei-mediated drug delivery has the potential to change the way drugs are administered systemically, resulting in more effective therapeutics and less-invasive treatments.

Next-generation immuno-oncology agents: current momentum shifts in cancer immunotherapy

Cancer immunotherapy has reached a critical point, now that immune checkpoint inhibitors and two CAR-T products have received market approval in treating 16 types of cancers and 1 tissue-agnostic cancer indication. Accompanying these advances, the 2018 Nobel Prize was awarded for the discovery of immune checkpoint pathways, which has led to the revolution of anti-cancer treatments. However, expanding the indications of immuno-oncology agents and overcoming treatment resistance face mounting challenges. Although combination immunotherapy is an obvious strategy to pursue, the fact that there have been more failures than successes in this effort has served as a wake-up call, placing emphasis on the importance of building a solid scientific foundation for the development of next-generation immuno-oncology (IO) agents. The 2019 China Cancer Immunotherapy Workshop was held to discuss the current challenges and opportunities in IO. At this conference, emerging concepts and strategies for IO development were proposed, focusing squarely on correcting the immunological defects in the tumor microenvironment. New targets such as Siglec-15 and new directions including neoantigens, cancer vaccines, oncolytic viruses, and cytokines were reviewed. Emerging immunotherapies were discussed in the areas of overcoming primary and secondary resistance to existing immune checkpoint inhibitors, activating effector cells, and targeting immunosuppressive mechanisms in the tumor microenvironment. In this article, we highlight old and new waves of IO therapy development, and provide perspectives on the latest momentum shifts in cancer immunotherapy.

Massively parallel interrogation and mining of natively paired human TCRαβ repertoires

T cells engineered to express antigen-specific T cell receptors (TCRs) are potent therapies for viral infections and cancer. However, efficient identification of clinical candidate TCRs is complicated by the size and complexity of T cell repertoires and the challenges of working with primary T cells. Here, we present a high-throughput method to identify TCRs with high functional avidity from diverse human T cell repertoires. The approach uses massively parallel microfluidics to generate libraries of natively paired, full-length TCRαβ clones, from millions of primary T cells, which are then expressed in Jurkat cells. The TCRαβ-Jurkat libraries enable repeated screening and panning for antigen-reactive TCRs using peptide:MHC binding and cellular activation. We captured >2.9 million natively paired TCRαβ clonotypes from six healthy human donors and identified rare (<0.001% frequency) viral antigen–reactive TCRs. We also mined a tumor-infiltrating lymphocyte (TIL) sample from a melanoma patient and identified several tumor-specific TCRs, which, after expression in primary T cells, led to tumor cell killing.

T Cell Dysfunction and Exhaustion in Cancer

Tumor immunotherapy is a promising therapeutic strategy for patients with advanced cancers. T cells are key mediators of antitumor function that specifically recognize and react to tumor-expressing antigens and have proven critical for cancer immunotherapy. However, T cells are not as effective against cancer as expected. This is partly because T cells enter a dysfunctional or exhausted state, which is characterized by sustained expression of inhibitory receptors and a transcriptional state distinct from that of functional effector or memory T cells. T cell dysfunction induces the out of control of tumors. Recently, T cell dysfunction has been investigated in many experimental and clinical settings. The molecular definition of T cell dysfunction and the underlying causes of the T cell dysfunction has been advanced regardless of the fact that the pathways involved are not well elucidated, which proposing promising therapeutic opportunities in clinic. In this review, we will discuss the recent advances in the molecular mechanisms that affect TME and induce T cell dysfunction, and the development of promising immunotherapies to counteract the mechanisms of tumor-induced T cell dysfunction. Better understanding these underlying mechanisms may lead to new strategies to improve the clinical outcome of patients with cancer.

Enhancing cancer immunotherapy with nanomedicine

Therapeutic targeting of the immune system in cancer is now a clinical reality and marked successes have been achieved, most notably through the use of checkpoint blockade antibodies and chimeric antigen receptor T cell therapy. However, efforts to develop new immunotherapy agents or combination treatments to increase the proportion of patients who benefit have met with challenges of limited efficacy and/or significant toxicity. Nanomedicines - therapeutics composed of or formulated in carrier materials typically smaller than 100 nm - were originally developed to increase the uptake of chemotherapy agents by tumours and to reduce their off-target toxicity. Here, we discuss how nanomedicine-based treatment strategies are well suited to immunotherapy on the basis of nanomaterials' ability to direct immunomodulators to tumours and lymphoid organs, to alter the way biologics engage with target immune cells and to accumulate in myeloid cells in tumours and systemic compartments. We also discuss early efforts towards clinical translation of nanomedicine-based immunotherapy.

Single-Cell Multiplexed Proteomics on the IsoLight Resolves Cellular Functional Heterogeneity to Reveal Clinical Responses of Cancer Patients to Immunotherapies

Cancer immunotherapies, in particular adoptive T cell therapy and immune-checkpoint blockade therapy have demonstrated a remarkable success in the treatment of cancer. However, due to heterogeneous functionality and complex immune response of immune cells, it remains challenging to identify predictive biomarkers which have the potential to correlate with efficacy and adverse effects of immunotherapies and help selecting patients who might benefit from the therapy, developing more personalized therapeutics as well as reducing clinical trial cost. The single-cell IsoCode chip in conjunction with fluorescent ELISA-based assay enables a simultaneous detection up to 40+ proteins secreted from live single immune cells, providing a large portion of the assayable functions for each immune cell type, and thus precise assessment of multifunctional, or polyfunctional, heterogeneity of each immune cell type.This unique functional detection capability provides a powerful solution to unmet needs in immunotherapy patient profiling today. Recently, the single-cell metric termed polyfunctional strength index (PSI™) by IsoCode chip computed from preinfusion anti-CD19 chimeric antigen receptor (CAR)-T cell products has demonstrated a significant association with clinical response and cytokine release syndrome (CRS) of cancer patient to the therapy after cell product infusion. This chapter elucidates IsoPlexis single-cell highly multiplexed proteomic platform and provides technical details for characterizing cell products and various cell subsets from peripheral blood, bone marrow, or tumor tissues using this assay.

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.

Immunopathology of Recurrent Vulvovaginal Infections: New Aspects and Research Directions

Recurrent vulvovaginal infections (RVVI), a devastating group of mucosal infection, are severely affecting women's quality of life. Our understanding of the vaginal defense mechanisms have broadened recently with studies uncovering the inflammatory nature of bacterial vaginosis, inflammatory responses against novel virulence factors, innate Type 17 cells/IL-17 axis, neutrophils mediated killing of pathogens by a novel mechanism, and oxidative stress during vaginal infections. However, the pathogens have fine mechanisms to subvert or manipulate the host immune responses, hijack them and use them for their own advantage. The odds of hijacking increases, due to impaired immune responses, the net magnitude of which is the result of numerous genetic variations, present in multiple host genes, detailed in this review. Thus, by underlining the role of the host immune responses in disease etiology, modern research has clarified a major hypothesis shift in the pathophilosophy of RVVI. This knowledge can further be used to develop efficient immune-based diagnosis and treatment strategies for this enigmatic disease conditions. As for instance, plasma-derived MBL replacement, adoptive T-cell, and antibody-based therapies have been reported to be safe and efficacious in infectious diseases. Therefore, these emerging immune-therapies could possibly be the future therapeutic options for RVVI.

T-cell receptor gene therapy targeting melanoma-associated antigen-A4 by silencing of endogenous TCR inhibits tumor growth in mice and human

Genetically engineered T cells expressing a T-cell receptor (TCR) are powerful tools for cancer treatment and have shown significant clinical effects in sarcoma patients. However, mismatch of the introduced TCR α/β chains with endogenous TCR may impair the expression of transduced TCR, resulting in an insufficient antitumor capacity of modified T cells. Here, we report the development of immunotherapy using human lymphocytes transduced with a codon-optimized melanoma-associated antigen (MAGE)-A4 and HLA-A*2402-restricted TCR, which specifically downregulate endogenous TCR by small interfering RNA (si-TCR). We evaluated the efficacy of this immunotherapy in both NOD-SCID mice and uterine leiomyosarcoma patients. Our results revealed that transduced human lymphocytes exhibited high surface expression of the introduced tumor-specific TCR, enhanced cytotoxic activity against antigen-expressing tumor cells, and increased interferon-γ production by specific MAGE-A4 peptide stimulation. Retarded tumor growth was also observed in NOD-SCID mice inoculated with human tumor cell lines expressing both MAGE-A4 and HLA-A*2402. Furthermore, we report the successful management of a case of uterine leiomyosarcoma treated with MAGE-A4 si-TCR/HLA-A*2402 gene-modified T cells. Our results indicate that the TCR-modified T cell therapy is a promising novel strategy for cancer treatment.

Immunomodulatory Biscembranoids and Assignment of Their Relative and Absolute Configurations: Data Set Modulation in the Density Functional Theory/Nuclear Magnetic Resonance Approach

Five new biscembranoids, bistrochelides A-E (3-7), were isolated together with glaucumolides A (1) and B (2) from the soft coral Sarcophyton trocheliophorum. Their structures and absolute configurations were determined by spectroscopic methods, X-ray crystal diffraction, and DFT/NMR (density functional theory/nuclear magnetic resonance) and TDDFT/ECD (time-dependent density functional theory/electronic circular dichroism) calculations. A new approach is introduced to determine the relative configuration of a stereocenter through the dynamic evaluation of the mean absolute errors (MAEs) between the investigated diastereoisomers, moving from an "extended" to a more diagnostic "restricted" set of atoms. This research leads to the structure revision of glaucumolides A and B. In in vitro immunomodulatory screening, compounds 1 and 4 significantly induced the proliferation of CD3⁺ T cells, while compounds 1 and 5 significantly increased the CD4⁺/CD8⁺ ratio at 3 μM.

Emerging Cellular Therapies: T Cells and Beyond

Cellular therapies, including those based on T cells, are becoming approved options for clinicians treating a range of diseases. Cytotoxic T lymphocytes (CTLs) can be modified ex vivo to express receptors such as chimeric antigen receptors (CARs) or T cell receptors, allowing them to target tumour cells when infused back into patients with particular cancers. CTLs specific for viruses can be purified ex vivo and reinfused into patients transplanted with haematopoietic stem cells to help combat viral reactivation. Regulatory T cells (Tregs) can be expanded ex vivo for infusion into patients with autoimmunity or allergy, or into those at risk of rejecting transplanted cells or tissues, or suffering graft versus host disease. Effector and regulatory T cells can also be generated by infusion of patient-derived dendritic cells (DCs) conditioned in ways to elicit anti-tumour immunity (CTLs) or Tregs. All such therapies are resource-heavy (particularly in process regulation) and so must be initially targeted to patients that have limited treatment options, but also where they have a chance of being effective.

Magnetic Nanoclusters Armed with Responsive PD-1 Antibody Synergistically Improved Adoptive T-Cell Therapy for Solid Tumors

Although adoptive T-cell therapy has been successful in hematological malignancy treatment, its application in solid tumors remains a great challenge. Here, using a pH-sensitive benzoic-imine bond and inverse electron-demand Diels-Alder cycloaddition, we prepared magnetic nanoclusters (NCs) armed with responsive PD-1 antibody (aP), which could then bind onto effector T cells due to their PD-1 expression. After adoptive transfer, the magnetization and superparamagnetism of NCs enabled us to magnetically recruit effector T cells and aP simultaneously to tumor sites with MRI guidance. Owing to the acidic intratumoral microenvironment, the benzoic-imine bond then hydrolyzed, leading to the release of aP. The therapeutic effects of adoptive T cells and free aP could thus be spatiotemporally coupled. As a result, we achieved inhibition of tumor growth with few side effects, demonstrating the great promise of such a chemical approach for safe and high-performance adoptive T-cell therapy against solid tumors.

BRAF Targeting Sensitizes Resistant Melanoma to Cytotoxic T Cells

PURPOSE

BRAF and MEK inhibitors (BRAFi and MEKi) are actively used for the treatment of metastatic melanoma in patients with BRAF^V600E mutation in their tumors. However, the development of resistance to BRAFi and MEKi remains a difficult clinical challenge with limited therapeutic options available to these patients. In this study, we investigated the mechanism and potential therapeutic utility of combination BRAFi and adoptive T-cell therapy (ACT) in melanoma resistant to BRAFi.

EXPERIMENTAL DESIGN

Investigations were performed in vitro and in vivo with various human melanoma cell lines sensitive and resistant to BRAFi as well as patient-derived xenografts (PDX) derived from patients. In addition, samples were evaluated from patients on a clinical trial of BRAFi in combination with ACT.

RESULTS

Herein we report that in human melanoma cell lines, senstitive and resistant to BRAFi and in PDX from patients who progressed on BRAFi and MEKi therapy, BRAFi caused transient upregulation of mannose-6-phosphate receptor (M6PR). This sensitized tumor cells to CTLs via uptake of granzyme B, a main component of the cytotoxic activity of CTLs. Treatment of mice bearing resistant tumors with BRAFi enhanced the antitumor effect of patients' TILs. A pilot clinical trial of 16 patients with metastatic melanoma who were treated with the BRAFi vemurafenib followed by therapy with TILs demonstrated a significant increase of M6PR expression on tumors during vemurafenib treatment.

CONCLUSIONS

BRAF-targeted therapy sensitized resistant melanoma cells to CTLs, which opens new therapeutic opportunities for the treatment of patients with BRAF-resistant disease.See related commentary by Goff and Rosenberg, p. 2682.

CRISPR/Cas9 and CAR-T cell, collaboration of two revolutionary technologies in cancer immunotherapy, an instruction for successful cancer treatment

Clustered regularly interspaced short palindromic repeats/CRISPR associated nuclease9 (CRISPR/Cas9) technology, an acquired immune system in bacteria and archaea, has provided a new tool for accurately genome editing. Using only a single nuclease protein in complex with 2 short RNA as a site-specific endonuclease made it a simple and flexible genome editing tool to target nearly any genomic locus. Due to recent developments in therapeutic engineered T cell and effective responses of CD19-directed chimeric antigen receptor T cells (CART19) in patients with B-cell leukemia and lymphoma, adoptive T cell immunotherapy, particularly CAR-T cell therapy became a rapidly growing field in cancer therapy and recently Kymriah and Yescarta (CD19-directed CAR-T cells) were approved by FDA. Therefore, the combination of CRISPR/Cas9 technology as a genome engineering tool and CAR-T cell therapy (engineered T cells that express chimeric antigen receptors) may lead to further improvement in efficiency and safety of CAR-T cells. This article reviews mechanism and therapeutic application of CRISPR/Cas9 technology, accuracy of this technology, cancer immunotherapy by CAR T cells, the application of CRISPR technology for the production of universal CAR T cells, improving their antitumor efficacy, and biotech companies that invested in CRISPR technology for CAR-T cell therapy.