Chimeric Antigen Receptor T-Cells: The Future is Now

Influence of Microbiota on Tumor Immunotherapy

The role of the microbiome in immunotherapy has recently garnered substantial attention, with molecular studies and clinical trials providing emerging evidence on the pivotal influence of the microbiota in enhancing therapeutic outcomes via immune response modulation. However, the impact of microbial communities can considerably vary across individuals and different immunotherapeutic approaches, posing prominent challenges in harnessing their potential. In this comprehensive review, we outline the current research applications in tumor immunotherapy and delve into the possible mechanisms through which immune function is influenced by microbial communities in various body sites, encompassing those in the gut, extraintestinal barrier, and intratumoral environment. Furthermore, we discuss the effects of diverse microbiome-based strategies, including probiotics, prebiotics, fecal microbiota transplantation, and the targeted modulation of specific microbial taxa, and antibiotic treatments on cancer immunotherapy. All these strategies potentially have a profound impact on immunotherapy and pave the way for personalized therapeutic approaches and predictive biomarkers.

Advances in CAR-Engineered Immune Cell Generation: Engineering Approaches and Sourcing Strategies

Chimeric antigen receptor T-cell (CAR-T) therapy has emerged as a highly efficacious treatment modality for refractory and relapsed hematopoietic malignancies in recent years. Furthermore, CAR technologies for cancer immunotherapy have expanded from CAR-T to CAR-natural killer cell (CAR-NK), CAR-cytokine-induced killer cell (CAR-CIK), and CAR-macrophage (CAR-MΦ) therapy. Nevertheless, the high cost and complex manufacturing processes of ex vivo generation of autologous CAR products have hampered broader application. There is an urgent need to develop an efficient and economical paradigm shift for exploring new sourcing strategies and engineering approaches toward generating CAR-engineered immune cells to benefit cancer patients. Currently, researchers are actively investigating various strategies to optimize the preparation and sourcing of these potent immunotherapeutic agents. In this work, the latest research progress is summarized. Perspectives on the future of CAR-engineered immune cell manufacturing are provided, and the engineering approaches, and diverse sources used for their development are focused upon.

Coengineering specificity, safety, and function into T cells for cancer immunotherapy

Adoptive T-cell transfer (ACT) therapies, including of tumor infiltrating lymphocytes (TILs) and T cells gene-modified to express either a T cell receptor (TCR) or a chimeric antigen receptor (CAR), have demonstrated clinical efficacy for a proportion of patients and cancer-types. The field of ACT has been driven forward by the clinical success of CD19-CAR therapy against various advanced B-cell malignancies, including curative responses for some leukemia patients. However, relapse remains problematic, in particular for lymphoma. Moreover, for a variety of reasons, relative limited efficacy has been demonstrated for ACT of non-hematological solid tumors. Indeed, in addition to pre-infusion challenges including lymphocyte collection and manufacturing, ACT failure can be attributed to several biological processes post-transfer including, (i) inefficient tumor trafficking, infiltration, expansion and retention, (ii) chronic antigen exposure coupled with insufficient costimulation resulting in T-cell exhaustion, (iii) a range of barriers in the tumor microenvironment (TME) mediated by both tumor cells and suppressive immune infiltrate, (iv) tumor antigen heterogeneity and loss, or down-regulation of antigen presentation machinery, (v) gain of tumor intrinsic mechanisms of resistance such as to apoptosis, and (vi) various forms of toxicity and other adverse events in patients. Affinity-optimized TCRs can improve T-cell function and innovative CAR designs as well as gene-modification strategies can be used to coengineer specificity, safety, and function into T cells. Coengineering strategies can be designed not only to directly support the transferred T cells, but also to block suppressive barriers in the TME and harness endogenous innate and adaptive immunity. Here, we review a selection of the remarkable T-cell coengineering strategies, including of tools, receptors, and gene-cargo, that have been developed in recent years to augment tumor control by ACT, more and more of which are advancing to the clinic.

Quantifying requirements for mitochondrial apoptosis in CAR T killing of cancer cells

Chimeric antigen receptor (CAR) T cell therapy is an FDA-approved treatment for several hematologic malignancies, yet not all patients respond to this treatment. While some resistance mechanisms have been identified, cell death pathways in target cancer cells remain underexplored. Impairing mitochondrial apoptosis via knockout of Bak and Bax, forced Bcl-2 and Bcl-XL expression, or caspase inhibition protected several tumor models from CAR T killing. However, impairing mitochondrial apoptosis in two liquid tumor cell lines did not protect target cells from CAR T killing. We found that whether a cell was Type I or Type II in response to death ligands explained the divergence of these results, so that mitochondrial apoptosis was dispensable for CART killing of cells that were Type I but not Type II. This suggests that the apoptotic signaling induced by CAR T cells bears important similarities to that induced by drugs. Combinations of drug and CAR T therapies will therefore require tailoring to the specific cell death pathways activated by CAR T cells in different types of cancer cells.

[Effects of sodium iodide symporter co-expression on proliferation and cytotoxic activity of chimeric antigen receptor T cells in vitro]

OBJECTIVE

To investigate the effects of co-expression of sodium iodide symporter (NIS) reporter gene on the proliferation and cytotoxic activity of chimeric antigen receptor (CAR)-T cells in vitro.

METHODS

T cells expressing CD19 CAR (CAR-T cells), NIS reporter gene (NIS-T cells), and both (NIS-CAR-T cells) were prepared by lentiviral infection. The transfection rates of NIS and CAR were determined by flow cytometry, and the cell proliferation rate was assessed using CCK-8 assay at 24, 48 and 72 h of routine cell culture. The T cells were co-cultured with Nalm6 tumor cells at the effector-target ratios of 1∶2, 1∶1, 2∶1 and 4∶1 for 24, 48 and 72 h, and the cytotoxicity of CAR-T cells to the tumor cells was evaluated using lactate dehydrogenase (LDH) assay. ELISA was used to detect the release of IFN-γ and TNF-β in the co-culture supernatant, and the function of NIS was detected with iodine uptake test.

RESULTS

The CAR transfection rate was 91.91% in CAR-T cells and 99.41% in NIS-CAR-T cells; the NIS transfection rate was 47.83% in NIS-T cells and 50.24% in NIS- CAR-T cells. No significant difference in the proliferation rate was observed between CAR-T and NIS-CAR-T cells cultured for 24, 48 or 72 h (P> 0.05). In the co-cultures with different effector-target ratios, the tumor cell killing rate was significantly higher in CAR-T group than in NIS-CAR-T group at 24 h (P < 0.05), but no significant difference was observed between the two groups at 48 h or 72 h (P>0.05). Higher IFN-γ and TNF-β release levels were detected in both CAR-T and NIS-CAR-T groups than in the control group (P < 0.05). NIS-T cells and NIS-CAR-T cells showed similar capacity of specific iodine uptake (P>0.05), which was significantly higher than that in the control T cells (P < 0.05).

CONCLUSION

The co-expression of the NIS reporter gene does not affect CAR expression, proliferation or tumor cell-killing ability of CAR-T cells.

Homeostatic cytokines tune naivety and stemness of cord blood-derived transgenic T cells

Engineered T-cell therapies have proven to be successful in cancer and their clinical effectiveness is directly correlated with the infused T-cell differentiation profile. Indeed, stem cell memory and central memory T cells proliferate and persist longer in vivo compared with more-differentiated T cells, while conferring enhanced antitumor activity. Here, we propose an optimized process using cord blood (CB) to generate minimally differentiated T-cell products in terms of phenotype, function, gene expression, and metabolism, using peripheral blood (PB)-derived T cells cultured with IL-2 as a standard. Phenotypically, CB-derived T cells, particularly CD4 T cells, are less differentiated than their PB counterparts when cultured with IL-2 or with IL-7 and IL-15. Furthermore, culture with IL-7 and IL-15 enables better preservation of less-differentiated CB-derived T cells compared with IL-2. In addition, transcriptomic and metabolic assessments of CB-derived transgenic T cells cultured with IL-7 and IL-15 point out their naivety and stemness signature. These relatively quiescent transgenic T cells are nevertheless primed for secondary stimulation and cytokine production. In conclusion, our study indicates that CB may be used as a source of early differentiated T cells to develop more effective adoptive cancer immunotherapy.

Update for Advance CAR-T Therapy in Solid Tumors, Clinical Application in Peritoneal Carcinomatosis From Colorectal Cancer and Future Prospects

Latest advances in the field of cancer immunotherapy have developed the (Chimeric Antigen Receptor) CAR-T cell therapy. This therapy was first used in hematological malignancies which obtained promising results; therefore, the use of CAR-T cells has become a popular approach for treating non-solid tumors. CAR-T cells consist of T-lymphocytes that are engineered to express an artificial receptor against any surface antigen of our choice giving us the capacity of offering precise and personalized treatment. This leaded to the development of CAR-T cells for treating solid tumors with the hope of obtaining the same result; however, their use in solid tumor and their efficacy have not achieved the expected results. The reason of these results is because solid tumors have some peculiarities that are not present in hematological malignancies. In this review we explain how CAR-T cells are made, their mechanism of action, adverse effect and how solid tumors can evade their action, and also we summarize their use in colorectal cancer and peritoneal carcinomatosis.

Identification and validation a costimulatory molecule gene signature to predict the prognosis and immunotherapy response for hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. Costimulatory molecules have been proven to be the foundation of immunotherapy. However, the potential roles of costimulatory molecule genes (CMGs) in HCC remain unclear. Our study is aimed to develop a costimulatory molecule-related gene signature that could evaluate the prognosis of HCC patients.

METHODS

Based on The Cancer Gene Atlas (TCGA) database, univariate Cox regression analysis was applied in CMGs to identify prognosis-related CMGs. Consensus clustering analysis was performed to stratify HCC patients into different subtypes and compared them in OS. Subsequently, the LASSO Cox regression analysis was performed to construct the CMGs-related prognostic signature and Kaplan-Meier survival curves as well as ROC curve were used to validate the predictive capability. Then we explored the correlations of the risk signature with tumor-infiltrating immune cells, tumor mutation burden (TMB) and response to immunotherapy. The expression levels of prognosis-related CMGs were validated based on qRT-PCR and Human Protein Atlas (HPA) databases.

RESULTS

All HCC patients were classified into two clusters based on 11 CMGs with prognosis values and cluster 2 correlated with a poorer prognosis. Next, a prognostic signature of six CMGs was constructed, which was an independent risk factor for HCC patients. Patients with low-risk score were associated with better prognosis. The correlation analysis showed that the risk signature could predict the infiltration of immune cells and immune status of the immune microenvironment in HCC. The qRT-PCR and immunohistochemical results indicated six CMGs with differential expression in HCC tissues and normal tissues.

CONCLUSION

In conclusion, our CMGs-related risk signature could be used as a prediction tool in survival assessment and immunotherapy for HCC patients.

Endoglin-Aptamer-Functionalized Liposome-Equipped PD-1-Silenced T Cells Enhance Antitumoral Immunotherapeutic Effects

Background

The broader application of adoptive cell therapy (ACT) in cancer immunotherapies (particularly for solid tumors) has always been limited by the immunosuppressive tumor microenvironment (TME) and the insufficient targetability of effector T cells, resulting in unsatisfied therapeutic outcome. Here, we designed a new strategy by using aptamer-based immunoliposomes to modify PD-1-silencing T cells, which were activated by dendritic cell (DC)/tumor fusion cells (FCs) to improve the antitumor potency of cytotoxic T lymphocytes (CTLs/CD8⁺ T cells).

Methods

PD-1 gene was knocked out from CD8⁺ T cells using CRISPR/Cas9 system to liberate T cell activity from immunosuppression. The PD-1⁻ T cells were stimulated with DC/tumor FCs, followed by further functional modification of tumor-specific nanoliposomes (hEnd-Apt/CD3-Lipo) to generate FC/PD-1⁻ CTLs. The activation and proliferation and specificity of the modified FC/PD-1⁻ CTLs were measured. The antitumor activity of these CTLs against HepG2-tumors was evaluated in xenograft NOD/SCID mice, and the antitumor mechanism was investigated based on tissue immunohistochemistry and serum ELISA.

Results

Our results indicated that the modification of hEnd-Apt/CD3-Lipo nanocomposites on the FC/PD-1⁻ CTLs had a more substantial synergetic effect in inhibiting tumor growth and prolonging animal survival, rather than other control liposomes. Furthermore, the hEnd-Apt/CD3-Lipo-modified FC/PD-1⁻ CTLs showed a stronger antitumor outcome in the tumor-bearing mouse model, through the mechanisms of suppressing tumor cell proliferation, promoting tumor apoptosis, reducing angiogenesis but increasing the infiltration of the FC/PD-1⁻ CTLs in the tumor tissue, as well as upregulating the systemic levels of IFN-γ, IL-2, TNF-α and IL-6 cytokines, by comparison of the control settings.

Conclusion

In sum, our investigation suggests an enhancement of antitumor effect by the surface modification of endoglin-targeting nanoliposomes upon DC/tumor FC-activated PD-1⁻ CTLs, therefore, provides a new tumoral endoglin-targeted approach as a promising strategy to reduce immunosuppression of tumor microenvironment and improve the immunotherapeutic outcome of anticancer ACT.

Chimeric antigen receptor T-cells (CARs) in cancer treatment

BACKGROUND

Cancer is one of the leading causes of death worldwide. Chemotherapy, radiation therapy, and stem cell transplantation were the main cancer treatment approaches for several years but due to their limited effectiveness, there was a constant search for new therapeutic approaches. Cancer immunotherapy that utilizes and enhances the normal capacity of the patient's immune system was used to fight against cancer. Genetically engineered T-cells that express chimeric antigen receptors (CARs) showed remarkable anti-tumor activity against hematologic malignancies and is now being investigated in a variety of solid tumors. The use of this therapy in the last few years has been successful, achieving a great success in improving the quality of life and prolonging the survival time of patients with a reduction in remission rates. However, many challenges still need to be resolved in order for this technology to gain widespread adoption. <P> Objective: This review summarizes various experimental approaches towards the use of CAR T-cells in hematologic malignancies and solid tumors. <P> Conclusion: Finally, we address the challenges posed by CAR T-cells and discuss strategies for improving the performance of these T cells in fighting cancers.

Cardiotoxicity Associated with Anti-CD19 Chimeric Antigen Receptor T-Cell (CAR-T) Therapy: Recognition, Risk Factors, and Management

Chimeric antigen receptor T-cells (CAR-T) are improving outcomes in pediatric and adult patients with relapsed or refractory B-cell acute lymphoblastic leukemias and subtypes of non-Hodgkin Lymphoma. As this treatment is being increasingly utilized, a better understanding of the unique toxicities associated with this therapy is warranted. While there is growing knowledge on the diagnosis and treatment of cytokine release syndrome (CRS), relatively little is known about the associated cardiac events that occur with CRS that may result in prolonged length of hospital stay, admission to the intensive care unit for pressor support, or cardiac death. This review focuses on the various manifestations of cardiotoxicity, potential risk factors, real world and clinical trial data on prevalence of reported cardiotoxicity events, and treatment recommendations.

An unmet need: Harmonization of IL-7 and IL-15 combination for the ex vivo generation of minimally differentiated T cells

T cell-based adoptive cell transfer therapy is now clinically used to fight cancer with CD19-targeting chimeric antigen receptor T cells. The use of other T cell-based immunotherapies relying on antigen-specific T cells, genetically modified or not, is expanding in various neoplastic diseases. T cell manufacturing has evolved through sophisticated processes to produce T cells with improved therapeutic potential. Clinical-grade manufacturing processes associated with these therapies must meet pharmaceutical requirements and therefore be standardized. Here, we focus on the use of cytokines to expand minimally differentiated T cells, as well as their standardization and harmonization in research and clinical settings.

Self-Adjuvanting Cancer Vaccines from Conjugation-Ready Lipid A Analogues and Synthetic Long Peptides

Self-adjuvanting vaccines, wherein an antigenic peptide is covalently bound to an immunostimulating agent, have been shown to be promising tools for immunotherapy. Synthetic Toll-like receptor (TLR) ligands are ideal adjuvants for covalent linking to peptides or proteins. We here introduce a conjugation-ready TLR4 ligand, CRX-527, a potent powerful lipid A analogue, in the generation of novel conjugate-vaccine modalities. Effective chemistry has been developed for the synthesis of the conjugation-ready ligand as well as the connection of it to the peptide antigen. Different linker systems and connection modes to a model peptide were explored, and in vitro evaluation of the conjugates showed them to be powerful immune-activating agents, significantly more effective than the separate components. Mounting the CRX-527 ligand at the N-terminus of the model peptide antigen delivered a vaccine modality that proved to be potent in activation of dendritic cells, in facilitating antigen presentation, and in initiating specific CD8⁺ T-cell-mediated killing of antigen-loaded target cells in vivo. Synthetic TLR4 ligands thus show great promise in potentiating the conjugate vaccine platform for application in cancer vaccination.

T-cell agonists in cancer immunotherapy

Cancer cells can evade immune surveillance in the body. However, immune checkpoint inhibitors can interrupt this evasion and enhance the antitumor activity of T cells. Other mechanisms for promoting antitumor T-cell function are the targeting of costimulatory molecules expressed on the surface of T cells, such as 4-1BB, OX40, inducible T-cell costimulator and glucocorticoid-induced tumor necrosis factor receptor. In addition, CD40 targets the modulation of the activation of antigen-presenting cells, which ultimately leads to T-cell activation. Agonists of these costimulatory molecules have demonstrated promising results in preclinical and early-phase trials and are now being tested in ongoing clinical trials. In addition, researchers are conducting trials of combinations of such immune modulators with checkpoint blockade, radiotherapy and cytotoxic chemotherapeutic drugs in patients with advanced tumors. This review gives a comprehensive picture of the current knowledge of T-cell agonists based on their use in recent and ongoing clinical trials.

Beyond thrombosis: the impact of tissue factor signaling in cancer

Tissue factor (TF) is the primary initiator of the coagulation cascade, though its effects extend well beyond hemostasis. When TF binds to Factor VII, the resulting TF:FVIIa complex can proteolytically cleave transmembrane G protein-coupled protease-activated receptors (PARs). In addition to activating PARs, TF:FVIIa complex can also activate receptor tyrosine kinases (RTKs) and integrins. These signaling pathways are utilized by tumors to increase cell proliferation, angiogenesis, metastasis, and cancer stem-like cell maintenance. Herein, we review in detail the regulation of TF expression, mechanisms of TF signaling, their pathological consequences, and how it is being targeted in experimental cancer therapeutics.

Peptide-based targeting of immunosuppressive cells in cancer

Cancer progression is marked by the infiltration of immunosuppressive cells, such as tumor-associated macrophages (TAMs), regulatory T lymphocytes (Tregs), and myeloid-derived suppressor cells (MDSCs). These cells play a key role in abrogating the cytotoxic T lymphocyte-mediated (CTL) immune response, allowing tumor growth to proceed unabated. Furthermore, targeting these immunosuppressive cells through the use of peptides and peptide-based nanomedicine has shown promising results. Here we review the origins and functions of immunosuppressive cells in cancer progression, peptide-based systems used in their targeting, and explore future avenues of research regarding cancer immunotherapy. The success of these studies demonstrates the importance of the tumor immune microenvironment in the propagation of cancer and the potential of peptide-based nanomaterials as immunomodulatory agents.

Regulatory T cells: the future of autoimmune disease treatment

Introduction: CD4 + T regulatory cells (Tregs) have been described as the most potent immunosuppressive cells in the human body. They have been found to control autoimmunity, and clinical attempts have been made to apply them to treat autoimmune diseases. Some specific pathways utilized by Tregs in the regulation of immune response or Tregs directly as cellular products are tested in the clinic. Areas covered: Here, we present recent advances in the research on the biology and clinical applications of Tregs in the treatment of autoimmune diseases. Expert opinion: Regulatory T cells seem to be a promising tool for the treatment of autoimmune diseases. The development of both cell-based therapies and modern pharmacotherapies which affect Tregs may strongly improve the treatment of autoimmune disorders. Growing knowledge about Treg biology together with the latest biotechnology tools may give an opportunity for personalized therapies in these conditions.

Pemphigus: Current and Future Therapeutic Strategies

Pemphigus encompasses a heterogeneous group of autoimmune blistering diseases, which affect both mucous membranes and the skin. The disease usually runs a chronic-relapsing course, with a potentially devastating impact on the patients' quality of life. Pemphigus pathogenesis is related to IgG autoantibodies targeting various adhesion molecules in the epidermis, including desmoglein (Dsg) 1 and 3, major components of desmosomes. The pathogenic relevance of such autoantibodies has been largely demonstrated experimentally. IgG autoantibody binding to Dsg results in loss of epidermal keratinocyte adhesion, a phenomenon referred to as acantholysis. This in turn causes intra-epidermal blistering and the clinical appearance of flaccid blisters and erosions at involved sites. Since the advent of glucocorticoids, the overall prognosis of pemphigus has largely improved. However, mortality persists elevated, since long-term use of high dose corticosteroids and adjuvant steroid-sparing immunosuppressants portend a high risk of serious adverse events, especially infections. Recently, rituximab, a chimeric anti CD20 monoclonal antibody which induces B-cell depletion, has been shown to improve patients' survival, as early rituximab use results in higher disease remission rates, long term clinical response and faster prednisone tapering compared to conventional immunosuppressive therapies, leading to its approval as a first line therapy in pemphigus. Other anti B-cell therapies targeting B-cell receptor or downstream molecules are currently tried in clinical studies. More intriguingly, a preliminary study in a preclinical mouse model of pemphigus has shown promise regarding future therapeutic application of Chimeric Autoantibody Receptor T-cells engineered using Dsg domains to selectively target autoreactive B-cells. Conversely, previous studies from our group have demonstrated that B-cell depletion in pemphigus resulted in secondary impairment of T-cell function; this may account for the observed long-term remission following B-cell recovery in rituximab treated patients. Likewise, our data support the critical role of Dsg-specific T-cell clones in orchestrating the inflammatory response and B-cell activation in pemphigus. Monitoring autoreactive T-cells in patients may indeed provide further information on the role of these cells, and would be the starting point for designating therapies aimed at restoring the lost immune tolerance against Dsg. The present review focuses on current advances, unmet challenges and future perspectives of pemphigus management.

Inflammation and Metabolism in Cancer Cell-Mitochondria Key Player

Cancer metabolism is an essential aspect of tumorigenesis, as cancer cells have increased energy requirements in comparison to normal cells. Thus, an enhanced metabolism is needed in order to accommodate tumor cells' accelerated biological functions, including increased proliferation, vigorous migration during metastasis, and adaptation to different tissues from the primary invasion site. In this context, the assessment of tumor cell metabolic pathways generates crucial data pertaining to the mechanisms through which tumor cells survive and grow in a milieu of host defense mechanisms. Indeed, various studies have demonstrated that the metabolic signature of tumors is heterogeneous. Furthermore, these metabolic changes induce the exacerbated production of several molecules, which result in alterations that aid an inflammatory milieu. The therapeutic armentarium for oncology should thus include metabolic and inflammation regulators. Our expanding knowledge of the metabolic behavior of tumor cells, whether from solid tumors or hematologic malignancies, may provide the basis for the development of tailor-made cancer therapies.