Extending the lifespan and efficacies of immune cells used in adoptive transfer for cancer immunotherapies-A review

Building a Better Defense: Expanding and Improving Natural Killer Cells for Adoptive Cell Therapy

Natural killer (NK) cells have gained attention as a promising adoptive cell therapy platform for their potential to improve cancer treatments. NK cells offer distinct advantages over T-cells, including major histocompatibility complex class I (MHC-I)-independent tumor recognition and low risk of toxicity, even in an allogeneic setting. Despite this tremendous potential, challenges persist, such as limited in vivo persistence, reduced tumor infiltration, and low absolute NK cell numbers. This review outlines several strategies aiming to overcome these challenges. The developed strategies include optimizing NK cell expansion methods and improving NK cell antitumor responses by cytokine stimulation and genetic manipulations. Using K562 cells expressing membrane IL-15 or IL-21 with or without additional activating ligands like 4-1BBL allows "massive" NK cell expansion and makes multiple cell dosing and "off-the-shelf" efforts feasible. Further improvements in NK cell function can be reached by inducing memory-like NK cells, developing chimeric antigen receptor (CAR)-NK cells, or isolating NK-cell-based tumor-infiltrating lymphocytes (TILs). Memory-like NK cells demonstrate higher in vivo persistence and cytotoxicity, with early clinical trials demonstrating safety and promising efficacy. Recent trials using CAR-NK cells have also demonstrated a lack of any major toxicity, including cytokine release syndrome, and, yet, promising clinical activity. Recent data support that the presence of TIL-NK cells is associated with improved overall patient survival in different types of solid tumors such as head and neck, colorectal, breast, and gastric carcinomas, among the most significant. In conclusion, this review presents insights into the diverse strategies available for NK cell expansion, including the roles played by various cytokines, feeder cells, and culture material in influencing the activation phenotype, telomere length, and cytotoxic potential of expanded NK cells. Notably, genetically modified K562 cells have demonstrated significant efficacy in promoting NK cell expansion. Furthermore, culturing NK cells with IL-2 and IL-15 has been shown to improve expansion rates, while the presence of IL-12 and IL-21 has been linked to enhanced cytotoxic function. Overall, this review provides an overview of NK cell expansion methodologies, highlighting the current landscape of clinical trials and the key advancements to enhance NK-cell-based adoptive cell therapy.

Forks in the road for CAR T and CAR NK cell cancer therapies

The advent of chimeric antigen receptor (CAR) T cell therapy has resulted in unprecedented long-term clearance of relapse/refractory hematological malignancies in both pediatric and adult patients. However, severe toxicities, such as cytokine release syndrome and neurotoxicity, associated with CAR T cells affect therapeutic utility; and treatment efficacies for solid tumors are still not impressive. As a result, engineering strategies that modify other immune cell types, especially natural killer (NK) cells have arisen. Owing to both CAR-dependent and CAR-independent (innate immune-mediated) antitumor killing capacity, major histocompatibility complex-independent cytotoxicity, reduced risk of alloreactivity and lack of major CAR T cell toxicities, CAR NK cells constitute one of the promising next-generation CAR immune cells that are also amenable as 'off-the-shelf' therapeutics. In this Review, we compare CAR T and CAR NK cell therapies, with particular focus on immunological synapses, engineering strategies and challenges.

Components of the Glutathione Cycle as Markers of Biological Age: An Approach to Clinical Application in Aging

The oxidative-inflammatory theory of aging states that aging is the result of the establishment of a chronic oxidative-inflammatory stress situation in which the immune system is implicated. Among the redox parameters, those involved in the glutathione cycle have been suggested as essential in aging. Thus, the first objective of this study was to determine if several components of the glutathione cycle (glutathione reductase (GR) and glutathione peroxidase (GPx) activities, and concentrations of oxidized glutathione (GSSG) and reduced glutathione (GSH)) in leukocytes) are associated with the biological age (ImmunolAge) estimated using the Immunity Clock in 190 men and women. The second objective was to identify the best blood fraction (whole blood, blood cells, erythrocytes, or plasma) to quantify these components and correlate them with the estimated ImmunolAge. The results show that the oxidative state of peripheral leukocytes correlates with their functionality, supporting the idea that this is the basis of immunosenescence. In blood, the correlations are more significant in the fraction of blood cells with respect to ImmunolAge (positive correlations with GSSG concentration and the GSSG/GSH ratio, and negative correlations with GPx and GR activities). Therefore, blood cells are proposed as the most effective sample to estimate the biological age of individuals in clinical settings.

Amoeboid migration in health and disease: Immune responses versus cancer dissemination

Cell migration is crucial for efficient immune responses and is aberrantly used by cancer cells during metastatic dissemination. Amoeboid migrating cells use myosin II-powered blebs to propel themselves, and change morphology and direction. Immune cells use amoeboid strategies to respond rapidly to infection or tissue damage, which require quick passage through several barriers, including blood, lymph and interstitial tissues, with complex and varied environments. Amoeboid migration is also used by metastatic cancer cells to aid their migration, dissemination and survival, whereby key mechanisms are hijacked from professionally motile immune cells. We explore important parallels observed between amoeboid immune and cancer cells. We also consider key distinctions that separate the lifespan, state and fate of these cell types as they migrate and/or fulfil their function. Finally, we reflect on unexplored areas of research that would enhance our understanding of how tumour cells use immune cell strategies during metastasis, and how to target these processes.

Adoptive NK-cell transfer as a potential treatment paradigm for Wilms tumor: A preclinical study

BACKGROUND

Natural killer (NK) cell therapy has been shown to be effective in the treatment of some cancers. However, the effects of this adoptive immunotherapy have not been investigated for Wilms tumor (WT). In this study, the effects of adoptive NK-cell transfer on a patient-derived xenograft (PDX) model of anaplastic WT were evaluated, and the impacts of cell source and ex vivo activation strategy on the therapeutic efficacy of NK-cell product were appraised.

METHODS

NK cells were isolated from human peripheral blood mononuclear cells (NK_PB ) and human cord blood (NK_CB ), and were expanded and activated using a cytokine cocktail. Another group of NK cells (NK_ET ) was produced through activation with the exosomes extracted from previously challenged NK_PB cells with WT. PDX-bearing mice were treated with clinically relevant doses of NK_PB , NK_CB , NK_ET , standard chemotherapy, and placebo (phosphate-buffered saline).

RESULTS

PDX models treated with NK_CB showed a better survival rate, though the difference among the study groups was not significant. Compared with the placebo control group, NK_CB significantly improved the histopathologic response, NK_PB significantly inhibited the proliferation of neoplastic cells, and NK_ET led to a significant decrease in the metastasis score (all p-values <.05). Standard chemotherapy provided the greatest tumor growth inhibition and the lowest mitotic count, though it did not show any significant advantage over NK-cell therapies in any of the outcome parameters in two-by-two comparisons.

CONCLUSIONS

This study spotlights the efficacy of adoptive NK-cell transfer as a potential treatment candidate for high-risk WT.

Engineered implantable vaccine platform for continuous antigen-specific immunomodulation

Cancer vaccines harness the host immune system to generate antigen-specific antitumor immunity for long-term tumor elimination with durable immunomodulation. Commonly investigated strategies reintroduce ex vivo autologous dendritic cells (DCs) but have limited clinical adoption due to difficulty in manufacturing, delivery and low clinical efficacy. To combat this, we designed the "NanoLymph", an implantable subcutaneous device for antigen-specific antitumor immunomodulation. The NanoLymph consists of a dual-reservoir platform for sustained release of immune stimulants via a nanoporous membrane and hydrogel-encapsulated antigens for local immune cell recruitment and activation, respectively. Here, we present the development and characterization of the NanoLymph as well as efficacy validation for immunomodulation in an immunocompetent murine model. Specifically, we established the NanoLymph biocompatibility and mechanical stability. Further, we demonstrated minimally invasive transcutaneous refilling of the drug reservoir in vivo for prolonging drug release duration. Importantly, our study demonstrated that local elution of two drugs (GMCSF and Resiquimod) generates an immune stimulatory microenvironment capable of local DC recruitment and activation and generation of antigen-specific T lymphocytes within 14 days. In summary, the NanoLymph approach can achieve in situ immunomodulation, presenting a viable strategy for therapeutic cancer vaccines.

Interconnections between Inflammageing and Immunosenescence during Ageing

Acute inflammation is a physiological response to injury or infection, with a cascade of steps that ultimately lead to the recruitment of immune cells to clear invading pathogens and heal wounds. However, chronic inflammation arising from the continued presence of the initial trigger, or the dysfunction of signalling and/or effector pathways, is harmful to health. While successful ageing in older adults, including centenarians, is associated with low levels of inflammation, elevated inflammation increases the risk of poor health and death. Hence inflammation has been described as one of seven pillars of ageing. Age-associated sterile, chronic, and low-grade inflammation is commonly termed inflammageing-it is not simply a consequence of increasing chronological age, but is also a marker of biological ageing, multimorbidity, and mortality risk. While inflammageing was initially thought to be caused by "continuous antigenic load and stress", reports from the last two decades describe a much more complex phenomenon also involving cellular senescence and the ageing of the immune system. In this review, we explore some of the main sources and consequences of inflammageing in the context of immunosenescence and highlight potential interventions. In particular, we assess the contribution of cellular senescence to age-associated inflammation, identify patterns of pro- and anti-inflammatory markers characteristic of inflammageing, describe alterations in the ageing immune system that lead to elevated inflammation, and finally assess the ways that diet, exercise, and pharmacological interventions can reduce inflammageing and thus, improve later life health.

High-Throughput immunogenetics for precision medicine in cancer

Cancer is characterized by an extremely complex biological background, which hinders personalized therapeutic interventions. Precision medicine promises to overcome this obstacle through integrating information from different 'subsystems', including the host, the external environment, the tumor itself and the tumor micro-environment. Immunogenetics is an essential tool that allows dissecting both lymphoid cancer ontogeny at both a cell-intrinsic and a cell-extrinsic level, i.e. through characterizing micro-environmental interactions, with a view to precision medicine. This is particularly thanks to the introduction of powerful, high-throughput approaches i.e. next generation sequencing, which allow the comprehensive characterization of immune repertoires. Indeed, NGS immunogenetic analysis (Immune-seq) has emerged as key to both understanding cancer pathogenesis and improving the accuracy of clinical decision making in oncology. Immune-seq has applications in lymphoid malignancies, assisting in the diagnosis e.g. through differentiating from reactive conditions, as well as in disease monitoring through accurate assessment of minimal residual disease. Moreover, Immune-seq facilitates the study of T cell receptor clonal dynamics in critical clinical contexts, including transplantation as well as innovative immunotherapy for solid cancers. The clinical utility of Immune-seq represents the focus of the present contribution, where we highlight what can be achieved but also what must be addressed in order to maximally realize the promise of Immune-seq in precision medicine in cancer.

Hybrid computational modeling demonstrates the utility of simulating complex cellular networks in type 1 diabetes

Persistent destruction of pancreatic β-cells in type 1 diabetes (T1D) results from multifaceted pancreatic cellular interactions in various phase progressions. Owing to the inherent heterogeneity of coupled nonlinear systems, computational modeling based on T1D etiology help achieve a systematic understanding of biological processes and T1D health outcomes. The main challenge is to design such a reliable framework to analyze the highly orchestrated biology of T1D based on the knowledge of cellular networks and biological parameters. We constructed a novel hybrid in-silico computational model to unravel T1D onset, progression, and prevention in a non-obese-diabetic mouse model. The computational approach that integrates mathematical modeling, agent-based modeling, and advanced statistical methods allows for modeling key biological parameters and time-dependent spatial networks of cell behaviors. By integrating interactions between multiple cell types, model results captured the individual-specific dynamics of T1D progression and were validated against experimental data for the number of infiltrating CD8+T-cells. Our simulation results uncovered the correlation between five auto-destructive mechanisms identifying a combination of potential therapeutic strategies: the average lifespan of cytotoxic CD8+T-cells in islets; the initial number of apoptotic β-cells; recruitment rate of dendritic-cells (DCs); binding sites on DCs for naïve CD8+T-cells; and time required for DCs movement. Results from therapy-directed simulations further suggest the efficacy of proposed therapeutic strategies depends upon the type and time of administering therapy interventions and the administered amount of therapeutic dose. Our findings show modeling immunogenicity that underlies autoimmune T1D and identifying autoantigens that serve as potential biomarkers are two pressing parameters to predict disease onset and progression.

Telomerase Reverse Transcriptase Increases Proliferation and Lifespan of Human NK Cells without Immortalization

NK cells are the first line of defense against viruses and malignant cells, and their natural functionality makes these cells a promising candidate for cancer cell therapy. The genetic modifications of NK cells, allowing them to overcome some of their inherent limitations, such as low proliferative potential, can enable their use as a therapeutic product. We demonstrate that hTERT-engineered NK cell cultures maintain a high percentage of cells in the S/G2 phase for an extended time after transduction, while the life span of NK cells is measurably extended. Bulk and clonal NK cell cultures pre-activated in vitro with IL-2 and K562-mbIL21 feeder cells can be transduced with hTERT more efficiently compared with the cells activated with IL-2 alone. Overexpressed hTERT was functionally active in transduced NK cells, which displayed upregulated expression of the activation marker HLA-DR, and decreased expression of the maturation marker CD57 and activating receptor NKp46. Larger numbers of KIR2DL2/3+ cells in hTERT-engineered populations may indicate that NK cells with this phenotype are more susceptible to transduction. The hTERT-modified NK cells demonstrated a high natural cytotoxic response towards K562 cells and stably expressed Ki67, a proliferation marker. Overall, our data show that ectopic hTERT expression in NK cells enhances their activation and proliferation, extends in vitro life span, and can be a useful tool in developing NK-based cancer cell therapies.

Systematic exploration of Astragalus membranaceus and Panax ginseng as immune regulators: Insights from the comparative biological and computational analysis

BACKGROUND

Immune system plays a decisive role for defending various pathogenic microorganisms. Astragalus membranaceus (AM) and Panax ginseng (PG) are two tonic herbs used in traditional Chinese medicine (TCM) as immune booster and help to control diseases with their healthy synergistic effect on immune system.

PURPOSE

This study was aimed to investigate the promote effect and molecular mechanisms of AM and PG on immune system as booster and to control the target diseases using animal and computational systematic study.

METHODS

Computational models including absorption, distribution, metabolism, and elimination (ADME) with weighted ensemble similarity (WES) algorithm-based models and ClueGo network analysis were used to find the potential bioactive compounds targets and pathways, which were responsible for immune regulation. Viscera index analysis, proliferation activity of splenic lymphocytes and cytotoxic activity of NK cells assays were performed to validate the effect of AM and PG on immune system of long-term administrated mice. Metabonomic study of mice plasma was conducted to investigate effect of AM and PG on the endogenous metabolic perturbations, together with correlation analysis.

RESULTS

AM and PG simultaneously showed the ability to strengthen the immune system function including enhancement of spleen and thymus index, proliferation of splenic lymphocytes and cytotoxic activity of NK cells. Besides, the different molecular mechanisms of AM and PG on immune regulation were also investigated by analyzing the potential bioactive compounds, enzymes actions and pathways. Quercetin, formononetin and kaempferol were the main immune-related compounds in AM, while ginsenoside Ra1, ginsenoside Rh1 and kaempferol in PG. About 10 target proteins were found close to immune regulation, including acetylcholinesterase (ACHE, common target in AM and PG), sphingosine kinase 1(SPHK1), cytidine deaminase (CDA), and Choline O-acetyltransferase (CHAT). Glycerophospholipid metabolism was regulated in both AM and PG groups. Pyrimidine metabolism and sphingolipid metabolism were considered as the special pathway in AM groups. Energy metabolism and glycerolipid metabolism were the special pathways in PG groups.

CONCLUSION

A novel comprehensive molecular mechanism analysis method was established and applied to clarify the scientific connotation of AM and PG as immune regulation, with similar herbal tonic effect provided in clinical practice of TCM, which can provide a new line of research for drug development (immune booster) using AM and PG.

Imaging of T-cell Responses in the Context of Cancer Immunotherapy

Immunotherapy, which promotes the induction of cytotoxic T lymphocytes and enhances their infiltration into and function within tumors, is a rapidly expanding and evolving approach to treating cancer. However, many of the critical denominators for inducing effective anticancer immune responses remain unknown. Efforts are underway to develop comprehensive ex vivo assessments of the immune landscape of patients prior to and during response to immunotherapy. An important complementary approach to these efforts involves the development of noninvasive imaging approaches to detect immune targets, assess delivery of immune-based therapeutics, and evaluate responses to immunotherapy. Herein, we review the merits and limitations of various noninvasive imaging modalities (MRI, PET, and single-photon emission tomography) and discuss candidate targets for cellular and molecular imaging for visualization of T-cell responses at various stages along the cancer-immunity cycle in the context of immunotherapy. We also discuss the potential use of these imaging strategies in monitoring treatment responses and predicting prognosis for patients treated with immunotherapy.

IL-15 Upregulates Telomerase Expression and Potently Increases Proliferative Capacity of NK, NKT-Like, and CD8 T Cells

Interleukin-15 (IL-15) is a cytokine that has been shown to expand CD8 T cell and natural killer (NK) cell populations, and therefore has potential for potentiating adoptive immune cell therapy for cancer. Previously, IL-15 has been shown to induce proliferation of CD8 memory T cells through activation of telomerase. Here, we investigated whether telomerase is also activated during the IL-15 mediated proliferation of NK and NKT-like (CD56+CD3+) cells. We also examined the extent that each of the three signaling pathways known to be stimulated by IL-2/IL-15 (JAK-STAT, PI3K-AKT Ras-RAF/MAPK) were activated and involved in the telomerase expression in the three cell types NK, NKT, or CD8 T cells. To assess cell proliferation and doubling, peripheral blood mononuclear cells (PBMCs) or isolated NK, NKT-like or CD8 T cells were incubated with varying concentrations of IL-15 or IL-2 for 7 days. CD8 T, NK, and NKT cell expansion was determined by fluorophore-conjugated antibody staining and flow cytometry. Cell doubling was investigated using carboxyfluorescein-succinimidyl-ester (CFSE). Telomerase expression was investigated by staining cells with anti-telomerase reverse transcriptase (anti-TERT). Telomerase activity in CD56+ and CD8 T cells was also measured via Telomerase Repeat Amplification Protocol (TRAP). Analysis of cellular expansion, proliferation and TERT expression concluded that IL-15 increased cellular growth of NK, NKT, and CD8 T cells more effectively than IL-2 using low or high doses. IL-15, increased TERT expression in NK and NKT cells by up to 2.5 fold, the same increase seen in CD8 T cells. IL-2 had effects on TERT expression only at high doses (100–1000 ng/ml). Proteome profiling identified that IL-15 activated selected signaling proteins in the three pathways (JAK-STAT, PI3K-AKT, Ras-MAPK) known to mediate IL-2/IL-15 signaling, more strongly than IL-2. Evaluation by signaling pathway inhibitors revealed that JAK/STAT and PI3K/AKT pathways are important in IL-15’s ability to upregulate TERT expression in NK and NKT cells, whereas all three pathways were involved in CD8 T cell TERT expression. In conclusion, this study shows that IL-15 potently stimulates TERT upregulation in NK and NKT cells in addition to CD8 T cells and is therefore a valuable tool for adoptive cell therapies.

Conditional Deletion of PGC-1α Results in Energetic and Functional Defects in NK Cells

During an immune response, natural killer (NK) cells activate specific metabolic pathways to meet the increased energetic and biosynthetic demands associated with effector functions. Here, we found in vivo activation of NK cells during Listeria monocytogenes infection-augmented transcription of genes encoding mitochondria-associated proteins in a manner dependent on the transcriptional coactivator PGC-1α. Using an Ncr1Cre-based conditional knockout mouse, we found that PGC-1α was crucial for optimal NK cell effector functions and bioenergetics, as the deletion of PGC-1α was associated with decreased cytotoxic potential and cytokine production along with altered ADP/ATP ratios. Lack of PGC-1α also significantly impaired the ability of NK cells to control B16F10 tumor growth in vivo, and subsequent gene expression analysis showed that PGC-1α mediates transcription required to maintain mitochondrial activity within the tumor microenvironment. Together, these data suggest that PGC-1α-dependent transcription of specific target genes is required for optimal NK cell function during the response to infection or tumor growth.

Senescence in the Development and Response to Cancer with Immunotherapy: A Double-Edged Sword

Cellular senescence was first described as a physiological tumor cell suppressor mechanism that leads to cell growth arrest with production of the senescence-associated secretory phenotype known as SASP. The main role of SASP in physiological conditions is to attract immune cells to clear senescent cells avoiding tumor development. However, senescence can be damage-associated and, depending on the nature of these stimuli, additional types of senescence have been described. In the context of cancer, damage-associated senescence has been described as a consequence of chemotherapy treatments that were initially thought of as a tumor suppressor mechanism. However, in certain contexts, senescence after chemotherapy can promote cancer progression, especially when immune cells become senescent and cannot clear senescent tumor cells. Moreover, aging itself leads to continuous inflammaging and immunosenescence which are responsible for rewiring immune cells to become defective in their functionality. Here, we define different types of senescence, pathways that activate them, and functions of SASP in these events. Additionally, we describe the role of senescence in cancer and its treatments, including how aging and chemotherapy contribute to senescence in tumor cells, before focusing on immune cell senescence and its role in cancer. Finally, we discuss potential therapeutic interventions to reverse cell senescence.

Characterizing the Dysfunctional NK Cell: Assessing the Clinical Relevance of Exhaustion, Anergy, and Senescence

There is a growing body of literature demonstrating the importance of T cell exhaustion in regulating and shaping immune responses to pathogens and cancer. Simultaneously, the parallel development of therapeutic antibodies targeting inhibitory molecules associated with immune exhaustion (such as PD-1, but also TIGIT, and LAG-3) has led to a revolution in oncology with dramatic benefits in a growing list of solid and hematologic malignancies. Given this success in reinvigorating exhausted T cells and the related anti-tumor effects, there are increasing efforts to apply immune checkpoint blockade to other exhausted immune cells beyond T cells. One approach involves the reinvigoration of “exhausted” NK cells, a non-T, non-B lymphoid cell of the innate immune system. However, in contrast to the more well-defined and established molecular, genetic, and immunophenotypic characteristics of T cell exhaustion, a consensus on the defining functional and phenotypic features of NK “exhaustion” is less clear. As is well-known from T cell biology, separate and distinct molecular and cellular processes including senescence, anergy and exhaustion can lead to diminished immune effector function with different implications for immune regulation and recovery. For NK cells, it is unclear if exhaustion, anergy, and senescence entail separate and distinct entities of dysfunction, though all are typically characterized by decreased effector function or proliferation. In this review, we seek to define these distinct spheres of NK cell dysfunction, analyzing how they have been shown to impact NK biology and clinical applications, and ultimately highlight key characteristics in NK cell function, particularly in relation to the role of “exhaustion.”

The challenges of adoptive cell transfer in the treatment of human renal cell carcinoma

Renal cell carcinoma (RCC) is one of the most lethal urologic malignancies. Its incidence continues to rise worldwide with a rate of 2% per year. Approximately, one-third of the RCC patients are diagnosed at advanced stages due to the asymptomatic nature of its early stages. This represents a great hurdle, since RCC is largely chemoresistant/radioresistant, and targeted therapy of mRCC still has limited efficacy. The 5-year survival rate of metastatic RCC (mRCC) is only around 10%. Adoptive cell transfer (ACT), a particular form of cell-based anticancer immunotherapy, is a promising approach in the treatment of mRCC. The vaccination principle, however, faces unique challenges that preclude the efficacy of ACT. In this article, we review the main challenges of ACT in the treatment of mRCC and describe multiple methods that can be used to overcome these challenges. In this respect, the ultimate purpose of this review is to provide a descriptive tool by which to improve the development of novel protocols for ACT of mRCC.

Imaging of T-cells and their responses during anti-cancer immunotherapy

Immunotherapy has proven to be an effective approach in a growing number of cancers. Despite durable clinical responses achieved with antibodies targeting immune checkpoint molecules, many patients do not respond. The common denominator for immunotherapies that have successfully been introduced in the clinic is their potential to induce or enhance infiltration of cytotoxic T-cells into the tumour. However, in clinical research the molecules, cells and processes involved in effective responses during immunotherapy remain largely obscure. Therefore, in vivo imaging technologies that interrogate T-cell responses in patients represent a powerful tool to boost further development of immunotherapy. This review comprises a comprehensive analysis of the in vivo imaging technologies that allow the characterisation of T-cell responses induced by anti-cancer immunotherapy, with emphasis on technologies that are clinically available or have high translational potential. Throughout we discuss their respective strengths and weaknesses, providing arguments for selecting the optimal imaging options for future research and patient management.

Preclinical Evaluation of Allogeneic CAR T Cells Targeting BCMA for the Treatment of Multiple Myeloma

Clinical success of autologous CD19-directed chimeric antigen receptor T cells (CAR Ts) in acute lymphoblastic leukemia and non-Hodgkin lymphoma suggests that CAR Ts may be a promising therapy for hematological malignancies, including multiple myeloma. However, autologous CAR T therapies have limitations that may impact clinical use, including lengthy vein-to-vein time and manufacturing constraints. Allogeneic CAR T (AlloCAR T) therapies may overcome these innate limitations of autologous CAR T therapies. Unlike autologous cell therapies, AlloCAR T therapies employ healthy donor T cells that are isolated in a manufacturing facility, engineered to express CARs with specificity for a tumor-associated antigen, and modified using gene-editing technology to limit T cell receptor (TCR)-mediated immune responses. Here, transcription activator-like effector nuclease (TALEN) gene editing of B cell maturation antigen (BCMA) CAR Ts was used to confer lymphodepletion resistance and reduced graft-versus-host disease (GvHD) potential. The safety profile of allogeneic BCMA CAR Ts was further enhanced by incorporating a CD20 mimotope-based intra-CAR off switch enabling effective CAR T elimination in the presence of rituximab. Allogeneic BCMA CAR Ts induced sustained antitumor responses in mice supplemented with human cytokines, and, most importantly, maintained their phenotype and potency after scale-up manufacturing. This novel off-the-shelf allogeneic BCMA CAR T product is a promising candidate for clinical evaluation.

Trained Immunity Carried by Non-immune Cells

“Trained immunity” is a term proposed by Netea to describe the ability of an organism to develop an exacerbated immunological response to protect against a second infection independent of the adaptative immunity. This immunological memory can last from 1 week to several months and is only described in innate immune cells such as monocytes, macrophages, and natural killer cells. Paradoxically, the lifespan of these cells in the blood is shorter than the duration of trained immunity. This observation suggested that trained immunity could be carried by long lifespan cells such as stem cells and non-immune cells like fibroblasts. It is now evident that in addition to performing their putative function in the development and maintenance of tissue homeostasis, non-immune cells also play an important role in the response to pathogens by producing anti-microbial factors, with long-term inflammation suggesting that non-immune cells can be trained to confer long-lasting immunological memory. This review provides a summary of the current relevant knowledge about the cells which possess immunological memory and discusses the possibility that non-immune cells may carry immunological memory and mechanisms that might be involved.

Differential Expression of Human N-Alpha-Acetyltransferase 40 (hNAA40), Nicotinamide Phosphoribosyltransferase (NAMPT) and Sirtuin-1 (SIRT-1) Pathway in Obesity and T2DM: Modulation by Metformin and Macronutrient Intake

BACKGROUND

Interactions between environmental factors, such as diet and lifestyle, and metabolic pathways are pivotal in understanding aging mechanisms. hNAA40, Nicotinamide phosphoribosyltransferase (NAMPT), and NAD-dependent protein deacetylase sirtuin-1 (SIRT-1) have been shown to exert important biological processes, including stress response and aging.

METHODS

hNAA40, NAMPT, and SIRT-1 mRNA expression in peripheral blood mononuclear cells (PBMC) were quantitated in 30 lean adult volunteers of normal weight, 30 obese, 20 drug-naïve obese Type 2 diabetes mellitus (T2DM), and 30 obese T2DM on Metformin. Similarly, hNAA40, NAMPT, and SIRT-1 expression in PBMC were quantitated in 36 normal healthy adults randomly assigned to three different groups (Glucose or Whey proteins or lipids; 300 kcal). Blood samples were obtained at 1, 2, and 3 hrs after the macronutrient intake.

RESULTS

There was an increase in hNAA40 and a decrease in NAMPT and SIRT-1 expression in PBMC from T2DM. Metformin treatment reverted hNAA40, NAMPT, and SIRT-1 expression levels to normal levels. Glucose intake resulted in a significant increase in expression of hNAA40 at 1 hr and decreased significantly at 3 hrs post intake. Lipid intake resulted in an increase in expression of hNAA40 at 2 hr post intake and returned to normal levels at 3 hrs. Neither glucose nor lipid intake resulted in a significant change in NAMPT or SIRT-1 expression. Whey proteins resulted in significantly lower expression of NAMPT at 3 hrs and did not alter the expression levels of SIRT-1 significantly.

CONCLUSION

hNAA40, NAMPT, and SIRT-1 pathway could play a role in the determination of the healthy life-span. Metformin modulates this pathway.

Injectable, Tough Alginate Cryogels as Cancer Vaccines

A covalently crosslinked methacrylated (MA)-alginate cryogel vaccine has been previously shown to generate a potent response against murine melanoma, but is not mechanically robust and requires a large 16G needle for delivery. Here, covalent and ionic crosslinking of cryogels are combined with the hypothesis that this will result in a tough MA-alginate cryogel with improved injectability. All tough cryogels can be injected through a smaller, 18G needle without sustaining any damage, while covalently crosslinked-only cryogels break after injection. Cytosine-phosphodiester-guanine (CpG)-delivering tough cryogels effectively activate dendritic cells (DCs). Granulocyte macrophage colony-stimulating factor releasing tough cryogels recruit four times more DCs than blank gels by day 7 in vivo. The tough cryogel vaccine induces strong antigen-specific cytotoxic T-lymphocyte and humoral responses. These vaccines prevent tumor formation in 80% of mice inoculated with HER2/neu-overexpressing DD breast cancer cells. The MA-alginate tough cryogels provide a promising minimally invasive delivery platform for cancer vaccinations.

Autophagy-dependent danger signaling and adaptive immunity to poorly immunogenic tumors

Recent data suggest that autophagy does not influence spontaneous and therapy-elicited tumor infiltration by immune cells in murine models of melanoma and breast carcinoma. These findings, which have been obtained in the absence of a therapeutically relevant anticancer immune response, indicate that the intrinsically low immunogenicity of some tumors cannot be compensated for by increased danger signaling.

Highly efficient IL-21 and feeder cell-driven ex vivo expansion of human NK cells with therapeutic activity in a xenograft mouse model of melanoma

Natural killer (NK) cells are promising antitumor effector cells, but the generation of sufficient NK cell numbers for adoptive immunotherapy remains challenging. Therefore, we developed a method for highly efficient ex vivo expansion of human NK cells. Ex vivo expansion of NK cells in medium containing IL-2 and irradiated clinical-grade feeder cells (EBV-LCL) induced a 22-fold NK cell expansion after one week that was significantly increased to 53-fold by IL-21. Repeated stimulation with irradiated EBV-LCL and IL-2 and addition of IL-21 at the initiation of the culture allowed sustained NK cell proliferation with 10¹¹-fold NK cell expansion after 6 weeks. Compared to naive NK cells, expanded NK cells upregulated TRAIL, NKG2D, and DNAM-1, had superior cytotoxicity against tumor cell lines in vitro and produced more IFNγ and TNF-α upon PMA/Iono stimulation. Most importantly, adoptive transfer of NK cells expanded using feeder cells, IL-2 and IL-21 led to significant inhibition of tumor growth in a melanoma xenograft mouse model, which was greater than with NK cells activated with IL-2 alone. Intriguingly, adoptively transferred NK cells maintained their enhanced production of IFNγ and TNF-α upon ex vivo restimulation, although they rapidly lost their capacity to degranulate and mediate tumor cytotoxicity after the in vivo transfer. In conclusion, we developed a protocol for ex vivo NK cell expansion that results in outstanding cell yields. The expanded NK cells possess potent antitumor activity in vitro and in vivo and could be utilized at high numbers for adoptive immunotherapy in the clinic.