Persistence of adoptively transferred T cells with a kinetically engineered IL-2 receptor agonist

Boosting Energy Deprivation via Synchronous Interventions of Oxidative Phosphorylation and Glycolysis for Cancer Therapy with 1,8-Naphthyridine-Piperazine-Dithiocarbamate Ruthenium(II) Polypyridyl Complexes

Bioenergetic therapy targeting mitochondrial bioenergy is a promising therapeutic strategy for cancer. However, its clinical efficacy is limited by the metabolic adaptability of tumor cells, as they can switch between glycolytic and oxidative phosphorylation metabolic phenotypes to maintain energy homeostasis. In this study, we discovered 1,8-naphthyridine-piperazine-dithiocarbamate ruthenium(II) polypyridyl complexes (RuL1) that enhanced energy deprivation by inhibiting the activity of mitochondrial complex I and III, thereby disrupting oxidative phosphorylation. Simultaneously, RuL1 inhibits glycolysis while unexpectedly activating antitumor immunity. This dual metabolic-immunological targeting resulted in enhanced anticancer activity against MGC-803 cells. To the best of our knowledge, RuL1 is the first ruthenium polypyridyl complex reported to achieve high anticancer activity through dual metabolic inhibition.

Flagellin engineering enhances CAR-T cell function by reshaping tumor microenvironment in solid tumors

BACKGROUND

Adoptive cell therapy using genetically engineered chimeric antigen receptor (CAR)-T cells is a new type of immunotherapy that directs T cells to target cancer specifically. Although CAR-T therapy has achieved significant clinical efficacy in treating hematologic malignancies, its therapeutic benefit in solid tumors is impeded by the immunosuppressive tumor microenvironment (TME). Therefore, we sought to remodel the TME by activating tumor-infiltrating immune cells to enhance the antitumor function of CAR-T cells.

METHODS

We engineered CAR-T cells expressing Salmonella flagellin (Fla), a ligand for toll-like receptor 5, to activate immune cells and reshape the TME in solid tumors. Functional validation of the novel Fla-engineered CAR-T cells was performed in co-cultures and mouse tumor models.

RESULTS

Fla could activate tumor-associated macrophages and dendritic cells, reshaping the TME to establish an "immune-hot" milieu. Notably, this "cold" to "hot" evolution not only improved CAR-T cell function for better control of target-positive tumors, but also encouraged the production of endogenous cytotoxic CD8+T cells, which targeted more tumor-associated antigens and were thus more effective against tumors with antigenic heterogeneity.

CONCLUSION

Our study reveals the potential and cellular mechanisms for Fla to rewire antitumor immunity. It also implies that modifying CAR-T cells to express Fla is a viable strategy to improve the efficacy of CAR-T cell treatment against solid tumors.

Cytokine Couture: Designer IL2 Molecules for the Treatment of Disease

Interleukin 2 (IL2) is a dual-acting cytokine, playing important roles in both immune activation and regulation. The role IL2 plays as a potent activator of CD8 T cells saw IL2 become one of the earliest immunotherapies, used for the treatment of cancer. In more recent years refined understanding of IL2, and the potent capacity it has for Treg stimulation, has seen low-dose IL2 therapy trialled for the treatment of auto-immune and inflammatory conditions. However, despite clinical successes, IL2 therapy is not without its caveats. The complicated receptor biology of IL2 gives rise to a narrow therapeutic window, made problematic by its short half-life. Armed with a better understanding of the structure of IL2 in complex with its receptors, many attempts have been made to create designer IL2 molecules which overcome these problems. A wide range of approaches have been used, resulting in >100 designer IL2 molecules. These include antibody complexes, fusion proteins, mutant IL2 molecules and PEGylation, each uniquely modifying the biological activity in an effort to enhance its therapeutic potential. Collectively, designer IL2 molecules form a blueprint outlining modification pathways available to other immunotherapeutics, paving the way for the next generation of immunotherapy.

Characteristics of Neonatal Sepsis and Predictive Values of Polyfunctional Assessment of Umbilical Cord Neutrophils Based on Single Cell Proteomic Secretion

The early diagnosis of neonatal sepsis is crucial as it remains a prevalent cause of neonatal mortality. In this study, we conducted an analysis on the clinical data and detection indicators of 22 cases with sepsis and 62 cases without sepsis among neonates. Our findings indicate that the clinical signs observed in neonates with sepsis lack specificity. In addition, the commonly used clinical inflammatory indicators (such as leukocyte count, neutrophil-to-lymphocyte ratio [NLR], C-reactive protein [CRP], procalcitonin) exhibit limited sensitivity and specificity. Furthermore, the current clinical measures lack the assessment of inflammatory factors. Therefore, in order to enhance the accuracy of early sepsis diagnosis in neonates, we have employed a novel microfluidic-based single-cell technology platform for the analysis of 32 cytokines secreted by neutrophils at the individual cell level under various toxin stimulation conditions. We have further investigated and compared the disparities in single-cell protein secretomics between umbilical cord blood neutrophils and healthy adult peripheral neutrophils within an in vitro sepsis model. Our findings indicate that in a resting state UCB neutrophils exhibited lower polyfunctionality compared with healthy adult blood neutrophils, and notable variations in cytokine secretion profiles were detected between the two groups. However, the polyfunctionality of UCB neutrophils significantly increased and surpassed that of healthy adult neutrophils when exposed to alpha-hemolysin or lipopolysaccharide. UCB neutrophils secreted a wide range of chemokines and inflammatory factors, among which GM-CSF and IL-18 were the most significant. Furthermore, we initially categorized the functional subgroups of neutrophils by considering the secretion of five primary cytokines by neutrophils (GM-CSF, IL-18, IL-8, MIP-1β, and MIF). The current study, for the first time, examined in detail the heterogeneity of protein secretion and the functional diversity of UCB neutrophils stimulated by different antigens. Moreover, new insight into neonatal sepsis, early diagnosis, and wider clinical applications of UCB neutrophils are provided by these data.

Cytokines in Focus: IL-2 and IL-15 in NK Adoptive Cell Cancer Immunotherapy

NK cell adoptive cell therapy (ACT) has emerged as a promising strategy for cancer immunotherapy, offering advantages in scalability, accessibility, efficacy, and safety. Ex vivo activation and expansion protocols, incorporating feeder cells and cytokine cocktails, have enabled the production of highly functional NK cells in clinically relevant quantities. Advances in NK cell engineering, including CRISPR-mediated gene editing and chimeric Ag receptor technologies, have further enhanced cytotoxicity, persistence, and tumor targeting. Cytokine support post-adoptive transfer, particularly with IL-2 and IL-15, remains critical for promoting NK cell survival, proliferation, and anti-tumor activity despite persistent challenges such as regulatory T cell expansion and cytokine-related toxicities. This review explores the evolving roles of IL-2 and IL-15 in NK cell-based ACT, evaluating their potential and limitations, and highlights strategies to optimize these cytokines for effective cancer immunotherapy.

Proteomics appending a complementary dimension to precision oncotherapy

Recent advances in high-throughput proteomic profiling technologies have facilitated the precise quantification of numerous proteins across multiple specimens concurrently. Researchers have the opportunity to comprehensively analyze the molecular signatures in plentiful medical specimens or disease pattern cell lines. Along with advances in data analysis and integration, proteomics data could be efficiently consolidated and employed to recognize precise elementary molecular mechanisms and decode individual biomarkers, guiding the precision treatment of tumors. Herein, we review a broad array of proteomics technologies and the progress and methods for the integration of proteomics data and further discuss how to better merge proteomics in precision medicine and clinical settings.

Natural killer cell-based cancer immunotherapy: from basics to clinical trials

Cellular immunotherapy exploits the capacity of the human immune system in self-protection and surveillance to achieve the anti-tumor effects. Natural killer (NK) cells are lymphocytes of innate immune system and they display a unique inherent ability to identify and eliminate tumor cells. In this review, we first introduce the basic characteristics of NK cells in the physiological and pathological milieus, followed by a discussion of their effector function and immunosuppression in the tumor microenvironment. Clinical strategies and reports regarding NK cellular therapy are analyzed in the context of tumor treatment, especially against solid tumors. Given the widely studied T-cell therapy in the recent years, particularly the chimeric antigen receptor (CAR) T-cell therapy, we compare the technical features of NK- and T-cell based tumor therapies at the clinical front. Finally, the technical challenges and potential solutions for both T and NK cell-based immunotherapies in treating tumor malignancies are delineated. By overviewing its clinical applications, we envision the NK-cell based immunotherapy as an up-and-comer in cancer therapeutics.

iSECRETE: Integrating Microfluidics and DNA Proximity Amplification for Synchronous Single-Cell Activation and IFN-γ Secretion Profiling

Cytokines, crucial in immune modulation, impact disease progression when their secretion is dysregulated. Existing methods for profiling cytokine secretion suffer from time-consuming and labor-intensive processes and often fail to capture the dynamic nature of immune responses. Here, iSECRETE, an integrated platform that enables synchronous cell activation, wash-free, and target-responsive protein detection for single-cell IFN-γ cytokine secretion analysis within 30 min at room temperature is presented. By incorporating a DNA proximity assay (DPA) into a multifunctional microfluidic system, one-pot homogenous cytokine signal amplification, with a limit of detection of ≈50 secreted molecules per cell is achieved. iSECRETE can robustly handle various sample types that are shown. Two distinct immune activation assay modalities are demonstrated on iSECRETE. Finally, the detection of single-cell IFN-γ secretion as an activation hallmark of chimeric antigen receptor T cells within 6 h of exposure to cancer targets is shown. iSECRETE represents the fastest single-cell sample-to-result cytokine secretion assay to date, providing a powerful tool for advancing the understanding of biological phenotypes, functions, and pathways under in vivo-like conditions.

Dipeptidyl peptidase-4 marks distinct subtypes of human adipose stromal/stem cells with different hepatocyte differentiation and immunoregulatory properties

BACKGROUND

Human adipose-derived stromal/stem cells (hASCs) play important roles in regenerative medicine and numerous inflammatory diseases. However, their cellular heterogeneity limits the effectiveness of treatment. Understanding the distinct subtypes of hASCs and their phenotypic implications will enable the selection of appropriate subpopulations for targeted approaches in regenerative medicine or inflammatory diseases.

METHODS

hASC subtypes expressing dipeptidyl peptidase-4 (DPP4) were identified via fluorescence-activated cell sorting (FACS) analysis. DPP4 expression was knocked down in DPP4+ hASCs via DPP4 siRNA. The capacity for proliferation, hepatocyte differentiation, inflammatory factor secretion and T-cell functionality regulation of hASCs from DPP4-, DPP4+, and control siRNA-treated DPP4+ hASCs and DPP4 siRNA-treated DPP4+ hASCs were assessed.

RESULTS

DPP4+ hASCs and control siRNA-treated DPP4+ hASCs presented a lower proliferative capacity but greater hepatocyte differentiation capacity than DPP4- hASCs and DPP4 siRNA-treated DPP4+ hASCs. Both DPP4+ hASCs and DPP4- hASCs secreted high levels of vascular endothelial growth factor-A (VEGF-A), monocyte chemoattractant protein-1 (MCP-1), and interleukin 6 (IL-6), whereas the levels of other factors, including matrix metalloproteinase (MMP)-1, eotaxin-3, fractalkine (FKN, CX3CL1), growth-related oncogene-alpha (GRO-alpha, CXCL1), monokine induced by interferon-gamma (MIG), macrophage inflammatory protein (MIP)-1beta, and macrophage colony-stimulating factor (M-CSF), were significantly greater in the supernatants of DPP4+ hASCs than in those of DPP4- hASCs. Exposure to hASC subtypes and their conditioned media triggered changes in the secreted cytokine profiles of T cells from healthy donors. The percentage of functional T cells that secreted factors such as MIP-1beta and IL-8 increased when these cells were cocultured with DPP4+ hASCs. The percentage of polyfunctional CD8+ T cells that secreted multiple factors, such as IL-17A, tumour necrosis factor alpha (TNF-α) and TNF-β, decreased when these cells were cocultured with supernatants derived from DPP4+ hASCs.

CONCLUSIONS

DPP4 may regulate proliferation, hepatocyte differentiation, inflammatory cytokine secretion and T-cell functionality of hASCs. These data provide a key foundation for understanding the important role of hASC subpopulations in the regulation of T cells, which may be helpful for future immune activation studies and allow them to be customized for clinical application.

Baseline biomarkers of efficacy and on-treatment immune-profile changes associated with bempegaldesleukin plus nivolumab

In PIVOT IO 001 (NCT03635983), the combination of the investigational interleukin-2 agonist bempegaldesleukin (BEMPEG) with nivolumab (NIVO) had no added clinical benefit over NIVO monotherapy in unresectable/metastatic melanoma. Pre-defined baseline and on-treatment changes in selected biomarkers were analyzed to explore the potential mechanisms underlying the clinical observations. In each treatment arm, higher baseline tumor mutational burden or immune infiltration/inflammation was associated with improved efficacy compared with lower levels. On-treatment peripheral biomarker changes showed that BEMPEG + NIVO increased all immune cell subset counts interrogated, including regulatory T cells. This was followed by attenuation of the increase in CD8 + T cells, conventional CD4 + T cells, and systemic interferon gamma levels at later treatment cycles in the combination arm. Changes in tumor biomarkers were comparable between arms. These biomarker results help provide a better understanding of the mechanism of action of BEMPEG + NIVO and may help contextualize the clinical observations from PIVOT IO 001.

A novel dual mechanism-of-action bispecific PD-1-IL-2v armed by a "βγ-only" interleukin-2 variant

INTRODUCTION

Interleukin-2 (IL-2) is one of the first cytokines to be discovered as an immune agonist for cancer immunotherapy. Biased IL-2 variants had been discovered to eliminate Treg activation or enhance the tumor specific T cell cytotoxicity. However, all the biased IL-2 variants pose the risk to overstimulate immune response at a low-dose range. Here, we introduce a novel dual-MOA bispecific PD-1-IL-2v molecule with great anti-tumor efficacy in a high dosed manner.

METHODS

The novel IL-2 variant was designed by structural truncation and shuffling. The single armed bispecific PD-1-IL-2v molecule and IL-2v were studied by immune cell activations in vitro and in vivo and anti-tumor efficacy in mouse model.

RESULTS AND DISCUSSION

The IL-2 variant in this bispecific antibody only binds to IL-2Rβγ complex in a fast-on/off manner without α, β or γ single receptor binding. This IL-2v mildly activates T and NK cells without over stimulation, meanwhile it diminishes Treg activation compared to the wild type IL-2. This unique bispecific molecule with "βγ-only" IL-2v can not only "in-cis" stimulate and expand CD8 T and NK cells moderately without Treg activation, but also block the PD-1/L1 interaction at a similar dose range with monoclonal antibody.

Cytokine expression patterns predict suppression of vulnerable neural circuits in a mouse model of Alzheimer's disease

Alzheimer's disease is a neurodegenerative disorder characterized by progressive amyloid plaque accumulation, tau tangle formation, neuroimmune dysregulation, synapse an neuron loss, and changes in neural circuit activation that lead to cognitive decline and dementia. Early molecular and cellular disease-instigating events occur 20 or more years prior to presentation of symptoms, making them difficult to study, and for many years amyloid-β, the aggregating peptide seeding amyloid plaques, was thought to be the toxic factor responsible for cognitive deficit. However, strategies targeting amyloid-β aggregation and deposition have largely failed to produce safe and effective therapies, and amyloid plaque levels poorly correlate with cognitive outcomes. However, a role still exists for amyloid-β in the variation in an individual's immune response to early, soluble forms of aggregates, and the downstream consequences of this immune response for aberrant cellular behaviors and creation of a detrimental tissue environment that harms neuron health and causes changes in neural circuit activation. Here, we perform functional magnetic resonance imaging of awake, unanesthetized Alzheimer's disease mice to map changes in functional connectivity over the course of disease progression, in comparison to wild-type littermates. In these same individual animals, we spatiotemporally profile the immune milieu by measuring cytokines, chemokines, and growth factors across various brain regions and over the course of disease progression from pre-pathology through established cognitive deficit. We identify specific signatures of immune activation predicting hyperactivity followed by suppression of intra- and then inter-regional functional connectivity in multiple disease-relevant brain regions, following the pattern of spread of amyloid pathology.

Single-Cell CD4 and CD8 T-Cell Secretome Profiling Reveals Temporal and Niche Differences in Acute Myeloid Leukemia Following Immune Checkpoint Blockade Therapy

Acute myeloid leukemia (AML) is a heterogeneous malignancy of the blood primarily treated with intensive chemotherapy. The allogeneic T-cell antileukemic activity via donor lymphocyte infusions and stem cell transplantation suggests a potential role for checkpoint blockade therapy in AML. While clinical trials employing these treatments have fallen short of expected results, a deeper exploration into the functional states of T cells in AML could bridge this knowledge gap. In this study, we analyzed the polyfunctional activity of T cells in a cohort of patients with relapsed/refractory (RelRef) AML treated on the clinical trial (ClinicalTrials.gov identifier: NCT02397720) of combination therapy using azacitidine and nivolumab (Aza/Nivo). We utilized the single-cell polyfunctional multiplexed immune assay IsoPlexis to evaluate the CD4 and CD8 T cells in peripheral blood and bone marrow samples collected before and after immunotherapy. This revealed at a pseudobulk level that the CD4 T cells exhibited higher functional activity post-immunotherapy (post-IO), suggesting that CD4-directed therapies may play a role in RelRef AML. Additional single-cell analysis revealed significant differences in baseline polyfunctionality in bone marrows of responders as compared with nonresponders for both CD4 and CD8 T cells. Overall, this study highlights the impact of polyfunctional assessment in understanding CD4 and CD8 dynamics in contexts of therapy in AML.

SIGNIFICANCE

We found T-cell polyfunctionality differs between local and systemic microenvironments. Enhanced variability in proteomic profiles of bone marrow CD4 T cells post-IO suggests their pivotal role in AML treatment response. Single-cell analysis identified novel CD4 and CD8 T-cell functional groups linked to immunotherapy response within the bone marrow.

Selective targeting or reprogramming of intra-tumoral Tregs

Regulatory T cells (Tregs) are critical immunosuppressive cells that are frequently present in the tumor microenvironment of solid cancers and enable progression of tumors toward metastasis. The cells expand in response to tumor-associated antigens and are actively involved in bypassing immunotherapy with immune checkpoint inhibitors through integrating numerous environmental signals. A point here is that Tregs are clonally distinct in peripheral blood from tumor area. Currently, an effective and novel task in cancer immunotherapy is to selectively destabilize or deplete intra-tumoral Tregs in order to avoid systemic inflammatory events. Helios is a transcription factor expressed selectively by Tregs and promotes their stabilization, and Trps1 is a master regulator of intra-tumoral Tregs. Anti-CCR8 and the IL-2Rβγ agonist Bempegaldesleukin selectively target intra-tumoral Treg population, with the former approved to not elicit autoimmunity. Disarming Treg-related immunosuppression in tumors through diverting their reprogramming or promoting naïve T cell differentiation into cells with effector immune activating profile is another promising area of research in cancer immunotherapy. Blimp-1 inhibitors and glucocorticoid-induced TNFR-related protein agonists are example approaches that can be used for diverting Treg differentiation into Th1-like CD4+ T cells, thereby powering immunogenicity against cancer. Finally, selective target of intra-tumoral Tregs and their reprogramming into effector T cells is applicable using low-dose chemotherapy, and high-salt and high-tryptophan diet.

T cell-mediated curation and restructuring of tumor tissue coordinates an effective immune response

Antigen-specific T cells traffic to, are influenced by, and create unique cellular microenvironments. Here we characterize these microenvironments over time with multiplexed imaging in a melanoma model of adoptive T cell therapy and human patients with melanoma treated with checkpoint inhibitor therapy. Multicellular neighborhood analysis reveals dynamic immune cell infiltration and inflamed tumor cell neighborhoods associated with CD8+ T cells. T cell-focused analysis indicates T cells are found along a continuum of neighborhoods that reflect the progressive steps coordinating the anti-tumor immune response. More effective anti-tumor immune responses are characterized by inflamed tumor-T cell neighborhoods, flanked by dense immune infiltration neighborhoods. Conversely, ineffective T cell therapies express anti-inflammatory cytokines, resulting in regulatory neighborhoods, spatially disrupting productive T cell-immune and -tumor interactions. Our study provides in situ mechanistic insights into temporal tumor microenvironment changes, cell interactions critical for response, and spatial correlates of immunotherapy outcomes, informing cellular therapy evaluation and engineering.

Strategies to therapeutically modulate cytokine action

Cytokines are secreted or membrane-presented molecules that mediate broad cellular functions, including development, differentiation, growth and survival. Accordingly, the regulation of cytokine activity is extraordinarily important both physiologically and pathologically. Cytokine and/or cytokine receptor engineering is being widely investigated to safely and effectively modulate cytokine activity for therapeutic benefit. IL-2 in particular has been extensively engineered, to create IL-2 variants that differentially exhibit activities on regulatory T cells to potentially treat autoimmune disease versus effector T cells to augment antitumour effects. Additionally, engineering approaches are being applied to many other cytokines such as IL-10, interferons and IL-1 family cytokines, given their immunosuppressive and/or antiviral and anticancer effects. In modulating the actions of cytokines, the strategies used have been broad, including altering affinities of cytokines for their receptors, prolonging cytokine half-lives in vivo and fine-tuning cytokine actions. The field is rapidly expanding, with extensive efforts to create improved therapeutics for a range of diseases.

Multiomics and spatial mapping characterizes human CD8+ T cell states in cancer

Clinically relevant immunological biomarkers that discriminate between diverse hypofunctional states of tumor-associated CD8⁺ T cells remain disputed. Using multiomics analysis of CD8⁺ T cell features across multiple patient cohorts and tumor types, we identified tumor niche-dependent exhausted and other types of hypofunctional CD8⁺ T cell states. CD8⁺ T cells in "supportive" niches, like melanoma or lung cancer, exhibited features of tumor reactivity-driven exhaustion (CD8⁺ T_EX). These included a proficient effector memory phenotype, an expanded T cell receptor (TCR) repertoire linked to effector exhaustion signaling, and a cancer-relevant T cell-activating immunopeptidome composed of largely shared cancer antigens or neoantigens. In contrast, "nonsupportive" niches, like glioblastoma, were enriched for features of hypofunctionality distinct from canonical exhaustion. This included immature or insufficiently activated T cell states, high wound healing signatures, nonexpanded TCR repertoires linked to anti-inflammatory signaling, high T cell-recognizable self-epitopes, and an antiproliferative state linked to stress or prodeath responses. In situ spatial mapping of glioblastoma highlighted the prevalence of dysfunctional CD4⁺:CD8⁺ T cell interactions, whereas ex vivo single-cell secretome mapping of glioblastoma CD8⁺ T cells confirmed negligible effector functionality and a promyeloid, wound healing-like chemokine profile. Within immuno-oncology clinical trials, anti-programmed cell death protein 1 (PD-1) immunotherapy facilitated glioblastoma's tolerogenic disparities, whereas dendritic cell (DC) vaccines partly corrected them. Accordingly, recipients of a DC vaccine for glioblastoma had high effector memory CD8⁺ T cells and evidence of antigen-specific immunity. Collectively, we provide an atlas for assessing different CD8⁺ T cell hypofunctional states in immunogenic versus nonimmunogenic cancers.

Immune checkpoint blockade induces gut microbiota translocation that augments extraintestinal antitumor immunity

Gut microbiota, specifically gut bacteria, are critical for effective immune checkpoint blockade therapy (ICT) for cancer. The mechanisms by which gut microbiota augment extraintestinal anticancer immune responses, however, are largely unknown. Here, we find that ICT induces the translocation of specific endogenous gut bacteria into secondary lymphoid organs and subcutaneous melanoma tumors. Mechanistically, ICT induces lymph node remodeling and dendritic cell (DC) activation, which facilitates the translocation of a selective subset of gut bacteria to extraintestinal tissues to promote optimal antitumor T cell responses in both the tumor-draining lymph nodes (TDLNs) and the primary tumor. Antibiotic treatment results in decreased gut microbiota translocation into mesenteric lymph nodes (MLNs) and TDLNs, diminished DC and effector CD8+ T cell responses, and attenuated responses to ICT. Our findings illuminate a key mechanism by which gut microbiota promote extraintestinal anticancer immunity.

Nanomedicine embraces cancer radio-immunotherapy: mechanism, design, recent advances, and clinical translation

Cancer radio-immunotherapy, integrating external/internal radiation therapy with immuno-oncology treatments, emerges in the current management of cancer. A growing number of pre-clinical studies and clinical trials have recently validated the synergistic antitumor effect of radio-immunotherapy, far beyond the "abscopal effect", but it suffers from a low response rate and toxicity issues. To this end, nanomedicines with an optimized design have been introduced to improve cancer radio-immunotherapy. Specifically, these nanomedicines are elegantly prepared by incorporating tumor antigens, immuno- or radio-regulators, or biomarker-specific imaging agents into the corresponding optimized nanoformulations. Moreover, they contribute to inducing various biological effects, such as generating in situ vaccination, promoting immunogenic cell death, overcoming radiation resistance, reversing immunosuppression, as well as pre-stratifying patients and assessing therapeutic response or therapy-induced toxicity. Overall, this review aims to provide a comprehensive landscape of nanomedicine-assisted radio-immunotherapy. The underlying working principles and the corresponding design strategies for these nanomedicines are elaborated by following the concept of "from bench to clinic". Their state-of-the-art applications, concerns over their clinical translation, along with perspectives are covered.

Enhancing adoptive T-cell therapy with fucoidan-based IL-2 delivery microcapsules

Adoptive cell therapy (ACT) with antigen-specific T cells is a promising treatment approach for solid cancers. Interleukin-2 (IL-2) has been utilized in boosting the efficacy of ACT. However, the clinical applications of IL-2 in combination with ACT is greatly limited by short exposure and high toxicities. Herein, a complex coacervate was designed to intratumorally deliver IL-2 in a sustained manner and protect against proteolysis. The complex coacervate consisted of fucoidan, a specific IL-2 binding glycosaminoglycan, and poly-l-lysine, a cationic counterpart (FPC2). IL-2-laden FPC2 exhibited a preferential bioactivity in ex vivo expansion of CD8+T cells over Treg cells. Additionally, FPC2 was embedded in pH modulating injectable gel (FPC2-IG) to endure the acidic tumor microenvironment. A single intratumoral administration of FPC2-IG-IL-2 increased expansion of tumor-infiltrating cytotoxic lymphocytes and reduced frequencies of myeloid populations. Notably, the activation and persistency of tumor-reactive T cells were observed only in the tumor site, not in the spleen, confirming a localized effect of FPC2-IG-IL-2. The immune-favorable tumor microenvironment induced by FPC2-IG-IL-2 enabled adoptively transferred TCR-engineered T cells to effectively eradicate tumors. FPC2-IG delivery system is a promising strategy for T-cell-based immunotherapies.

IL-2/GM-CSF enhances CXCR3 expression in CAR-T cells via the PI3K/AKT and ERK1/2 pathways

OBJECTIVE

To investigate the effects of cytokines IL-2 and GM-CSF on CXCR3 expression and chemotaxis of CAR-T cells.

BACKGROUND

High lymphocyte infiltration within the tumor is a basic requirement for good results in tumor immunotherapy; C-X-C motif chemokine receptor 3 (CXCR3) is an important factor for the chemotaxis of lymphocytes to tumor tissues. The tumor microenvironment can exhibit diverse cytokine suppression or promote antitumor immunity. Both interleukin (IL)-2 and granulocyte macrophage colony-stimulating factor (GM-CSF) contribute to the regulation of immunosuppression in the tumor microenvironment. However, the effects of IL-2 and GM-CSF on CXCR3 expression on the T cell surface and its mechanisms are not well understood. Here, we explored the effects of polycytokines on CXCR3 expression in chimeric antigen receptor T cells (CAR-T cells) and on HuH-7 in situ hepatocellular carcinoma.

MATERIALS AND METHODS

Peripheral blood mononuclear cells (PBMCs) were isolated, followed by purifying using CD3 immunomagnetic beads. Cells were divided into three groups. After 24h of activation using CD3/CD28 antibody, T cells were transfected using lentiviral vector, pGC-SV40-EGFP-GPC3-CAR. Three culture methods were used to amplify the transfected T cells. Method 'A' was to incubate T cells with CD3/CD28 antibody; method 'B' was with CD3/CD28 antibody and IL-2 at a final concentration of 1000 U/ml; method 'C' was with method B in addition of GM-CSF at a final concentration of 1000 U/ml. The phosphorylation of MAPK and PI3K/AKT was determined by western blot. The chemotaxis effect of CAR-T cells on Huh-7 HCCIA in situ was assayed by immunofluorescence and immunohistochemistry.

RESULTS

The CD3/CD28/IL-2/GM-CSF combination is the most potent for stimulating activated CAR-T cell proliferation and CXCR3 expression in vitro; CD3/CD28/IL-2 induces CAR-T cell expression of CXCR3 through the activation of the PI3K/APK pathway and GM-CSF induces CXCR3 expression in CAR-T cells through the activation of ERK1/2 rather than the p38 MAPK signaling pathway. CAR-GPC3-T cells with high CXCR3 expression showed increased chemotaxis ability to HuH in situ hepatocellular carcinoma, and considerably inhibited the growth of in situ tumors in nude mouse livers.

CONCLUSION

A multi-factorial amplification protocol can effectively improve CXCR3 expression on the surface of activated CAR-T cells in vitro, as well as enhance the chemotaxis ability of CAR-T cells in vivo, which significantly inhibit the growth of liver cancer.

Expansion of T memory stem cells with superior anti-tumor immunity by Urolithin A-induced mitophagy

T memory stem cells (T_SCM) display increased self-renewal and prolonged survival capabilities, thus preventing T cell exhaustion and promoting effective anti-tumor T cell responses. T_SCM cells can be expanded by Urolithin A (UA), which is produced by the commensal gut microbiome from foods rich in ellagitannins and is known to improve mitochondrial health. Oral UA administration to tumor-bearing mice conferred strong anti-tumor CD8⁺ T cell immunity, whereas ex vivo UA pre-treated T cells displayed improved anti-tumor function upon adoptive cell transfer. UA-induced T_SCM formation depended on Pink1-mediated mitophagy triggering cytosolic release of the mitochondrial phosphatase Pgam5. Cytosolic Pgam5 dephosphorylated β-catenin, which drove Wnt signaling and compensatory mitochondrial biogenesis. Collectively, we unravel a critical signaling pathway linking mitophagy to T_SCM formation and suggest that the well-tolerated metabolic compound UA represents an attractive option to improve immune therapy.

The Potential Role of Cytotoxic Immune Effectors in Induction, Progression and Pathogenesis of Amyotrophic Lateral Sclerosis (ALS)

Amyotrophic lateral sclerosis (ALS) is an auto-immune neurodegenerative disorder affecting the motor-neuron system. The causes of ALS are heterogeneous, and are only partially understood. We studied different aspects of immune pathogenesis in ALS and found several basic mechanisms which are potentially involved in the disease. Our findings demonstrated that ALS patients' peripheral blood contains higher proportions of NK and B cells in comparison to healthy individuals. Significantly increased IFN-γ secretion by anti-CD3/28 mAbs-treated peripheral blood mononuclear cells (PBMCs) were observed in ALS patients, suggesting that hyper-responsiveness of T cell compartment could be a potential mechanism for ALS progression. In addition, elevated granzyme B and perforin secretion at a single cell level, and increased cytotoxicity and secretion of IFN-γ by patients' NK cells under specific treatment conditions were also observed. Increased IFN-γ secretion by ALS patients' CD8+ T cells in the absence of IFN-γ receptor expression, and increased CD8+ T cell effector/memory phenotype as well as increased granzyme B at the single cell level points to the CD8+ T cells as potential cells in targeting motor neurons. Along with the hyper-responsiveness of cytotoxic immune cells, significantly higher levels of inflammatory cytokines including IFN-γ was observed in peripheral blood-derived serum of ALS patients. Supernatants obtained from ALS patients' CD8+ T cells induced augmented cell death and differentiation of the epithelial cells. Weekly N-acetyl cysteine (NAC) infusion in patients decreased the levels of many inflammatory cytokines in peripheral blood of ALS patient except IFN-γ, TNF-α, IL-17a and GMCSF which remained elevated. Findings of this study indicated that CD8+ T cells and NK cells are likely culprits in targeting motor neurons and therefore, strategies should be designed to decrease their function, and eliminate the aggressive nature of these cells. Analysis of genetic mutations in ALS patient in comparison to identical twin revealed a number of differences and similarities which may be important in the pathogenesis of the disease.

Integrating Micro and Nano Technologies for Cell Engineering and Analysis: Toward the Next Generation of Cell Therapy Workflows

The emerging field of cell therapy offers the potential to treat and even cure a diverse array of diseases for which existing interventions are inadequate. Recent advances in micro and nanotechnology have added a multitude of single cell analysis methods to our research repertoire. At the same time, techniques have been developed for the precise engineering and manipulation of cells. Together, these methods have aided the understanding of disease pathophysiology, helped formulate corrective interventions at the cellular level, and expanded the spectrum of available cell therapeutic options. This review discusses how micro and nanotechnology have catalyzed the development of cell sorting, cellular engineering, and single cell analysis technologies, which have become essential workflow components in developing cell-based therapeutics. The review focuses on the technologies adopted in research studies and explores the opportunities and challenges in combining the various elements of cell engineering and single cell analysis into the next generation of integrated and automated platforms that can accelerate preclinical studies and translational research.

Engineering IL-2 for immunotherapy of autoimmunity and cancer

Preclinical studies of the T cell growth factor activity of IL-2 resulted in this cytokine becoming the first immunotherapy to be approved nearly 30 years ago by the US Food and Drug Administration for the treatment of cancer. Since then, we have learnt the important role of IL-2 in regulating tolerance through regulatory T cells (Treg cells) besides promoting immunity through its action on effector T cells and memory T cells. Another pivotal event in the history of IL-2 research was solving the crystal structure of IL-2 bound to its tripartite receptor, which spurred the development of cell type-selective engineered IL-2 products. These new IL-2 analogues target Treg cells to counteract the dysregulated immune system in the context of autoimmunity and inflammatory disorders or target effector T cells, memory T cells and natural killer cells to enhance their antitumour responses. IL-2 biologics have proven to be effective in preclinical studies and clinical assessment of some is now underway. These studies will soon reveal whether engineered IL-2 biologics are truly capable of harnessing the IL-2-IL-2 receptor pathway as effective monotherapies or combination therapies for autoimmunity and cancer.

IL-10 in cancer: an essential thermostatic regulator between homeostatic immunity and inflammation - a comprehensive review

Cytokines are soluble proteins that mediate intercellular signaling regulating immune and inflammatory responses. Cytokine modulation represents a promising cancer immunotherapy approach for immune-mediated tumor regression. However, redundancy in cytokine signaling and cytokines' pleiotropy, narrow therapeutic window, systemic toxicity, short half-life and limited efficacy represent outstanding challenges for cytokine-based cancer immunotherapies. Recently, there has been interest in the paradoxical role of IL-10 in cancer, its controversial prognostic utility and novel strategies to enhance its therapeutic profile. Here, the authors review the literature surrounding the role of IL-10 within the tumor microenvironment, its prognostic correlates to cancer patient outcomes and its pro- and antitumor effects, and they assess the legitimacy of potential therapeutic strategies harnessing IL-10 by outlining the notable preclinical and clinical evidence to date.

Immune checkpoints in osteosarcoma: Recent advances and therapeutic potential

Osteosarcoma is the most common primary malignant bone tumor and is associated with a high risk of recurrence and distant metastasis. Effective treatment for osteosarcoma, especially advanced osteosarcoma, has stagnated over the past four decades. The advent of immune checkpoint inhibitor (ICI) has transformed the treatment paradigm for multiple malignant tumor types and indicated a potential therapeutic strategy for osteosarcoma. In this review, we discuss recent advances in immune checkpoints, including programmed cell death protein-1 (PD-1), programmed cell death protein ligand-1 (PD-L1), and cytotoxic T lymphocyte-associated antigen-4 (CTLA-4), and their related ICIs for osteosarcoma treatment. We present the main existing mechanisms of resistance to ICIs therapy in osteosarcoma. Moreover, we summarize the current strategies for improving the efficacy of ICIs in osteosarcoma and address the potential predictive biomarkers of ICIs treatment in osteosarcoma.

Development of Immunotherapy Strategies Targeting Tumor Microenvironment Is Fiercely Ongoing

Tumor immune microenvironment is a very complex system that is influenced by a wide range of factors; in this microenvironment, various immune cells, stromal cells, and cytokines can interact with tumor cells and jointly regulate this complex ecosystem. During tumor development, the tumor microenvironment (TME) shows the upregulation of inhibitory signals and downregulation of activating signals, which result in an immunosuppressive microenvironment and lead to tumor immune escape. In recent years, a variety of precision immunotherapy strategies have been developed to remodel the TME into a positive immune microenvironment by stimulating or restoring the inherent tumor inhibition ability of the immune system so as to improve anti-tumor therapeutic efficacy. This review focuses on immunotherapy strategies targeting the TME, including those that target the microenvironment to inhibit signaling, activate signaling, and specifically involve many new targets such as physical barriers, immune cells and their surface molecular receptors, cytokines, and metabolic factors. Furthermore, it summarizes the challenges faced while conducting research on the tumor immune microenvironment and the corresponding solutions.

Fueling Cancer Vaccines to Improve T Cell-Mediated Antitumor Immunity

Cancer vaccines offer the potential to enhance T cell-mediated antitumor immunity by expanding and increasing the function of tumor-specific T cells and shaping the recall response against recurring tumors. While the use of cancer vaccines is not a new immunotherapeutic approach, the cancer vaccine field continues to evolve as new antigen types emerge and vaccine formulations and delivery strategies are developed. As monotherapies, cancer vaccines have not been very efficacious in part due to pre-existing peripheral- and tumor-mediated tolerance mechanisms that limit T cell function. Over the years, various agents including Toll-like receptor agonists, cytokines, and checkpoint inhibitors have been employed as vaccine adjuvants and immune modulators to increase antigen-mediated activation, expansion, memory formation, and T effector cell function. A renewed interest in this approach has emerged as better neoepitope discovery tools are being developed and our understanding of what constitutes an effective cancer vaccine is improved. In the coming years, cancer vaccines will likely be vital to enhance the response to current immunotherapies. In this review, we discuss the various types of therapeutic cancer vaccines, including types of antigens and approaches used to enhance cancer vaccine responses such as TLR agonists, recombinant interleukin-2 and interleukin-2 derivatives, and checkpoint inhibitors.

Polymer-drug conjugates: Design principles, emerging synthetic strategies and clinical overview

Adagen, an enzyme replacement treatment for adenosine deaminase deficiency, was the first protein-polymer conjugate to be approved in early 1990s. Post this regulatory approval, numerous polymeric drugs and polymeric nanoparticles have entered the market as advanced or next-generation polymer-based therapeutics, while many others have currently been tested clinically. The polymer conjugation to therapeutic moiety offers several advantages, like enhanced solubilization of drug, controlled release, reduced immunogenicity, and prolonged circulation. The present review intends to highlight considerations in the design of therapeutically effective polymer-drug conjugates (PDCs), including the choice of linker chemistry. The potential synthetic strategies to formulate PDCs have been discussed along with recent advancements in the different types of PDCs, i.e., polymer-small molecular weight drug conjugates, polymer-protein conjugates, and stimuli-responsive PDCs, which are under clinical/preclinical investigation. Current impediments and regulatory hurdles hindering the clinical translation of PDC into effective therapeutic regimens for the amelioration of disease conditions have been addressed.

Therapeutic potential of interleukin-2 in autoimmune diseases

Autoimmune diseases are characterized by dysregulation and aberrant activation of cells in the immune system. Therefore, restoration of the immune balance represents a promising therapeutic target in autoimmune diseases. Interleukin-2 (IL-2) can promote the expansion and differentiation of different immune cell subsets dose-dependently. At high doses, IL-2 can promote the differentiation and expansion of effector and memory T cells, whereas at low doses, IL-2 can promote the differentiation, survival, and function of regulatory T (T_reg) cells, a CD4⁺ T cell subset that is essential for the maintenance of immune homeostasis and immune tolerance. Therefore, IL-2 exerts immunostimulatory and immunosuppressive effects in autoimmune diseases. The immunoregulatory role of low-dose IL-2 has sparked excitement for the therapeutic exploration of modulating the IL-2-T_reg axis in the context of autoimmune diseases. In this review, we discuss recent advances in the therapeutic potential of IL-2 or IL-2-derived molecules in the treatment of autoimmune diseases.

Tumor-infiltrating lymphocytes for adoptive cell therapy: recent advances, challenges, and future directions

INTRODUCTION

Adoptive cell therapy (ACT) with tumor-infiltrating lymphocytes (TILs) is a highly personalized type of cancer immunotherapy. TIL-based ACT exploits naturally occurring TILs, derived from the patients' tumor. This treatment has shown consistent clinical responses in melanoma, and recent results point toward a potential use in multiple cancer diagnoses. However, several limitations have restricted the clinical development and adaptation of TIL-based ACT.

AREAS COVERED

In this review, we present the principles of TIL-based ACT and discuss the most significant limitations for therapeutic efficacy and its widespread application. The topics of therapeutic resistance (both innate and acquired), treatment-related toxicity, and the novel research topic of metabolic barriers in the tumor microenvironment (TME) are covered.

EXPERT OPINION

There are many ongoing areas of research focusing on improving clinical efficacy and optimizing TIL-based ACT. Many strategies have shown great potential, particularly strategies advancing TIL efficacy (such as increasing and harnessing ex vivo the sub-population of tumor-reactive TILs) and manufacturing processes. Novel approaches can help overcome current limitations and potentially result in TIL-based ACT entering the mainstream of cancer therapy across tumor types.

ImmunoPET: harnessing antibodies for imaging immune cells

Dramatic, but uneven, progress in the development of immunotherapies for cancer has created a need for better diagnostic technologies including innovative non-invasive imaging approaches. This review discusses challenges and opportunities for molecular imaging in immuno-oncology and focuses on the unique role that antibodies can fill. ImmunoPET has been implemented for detection of immune cell subsets, activation and inhibitory biomarkers, tracking adoptively transferred cellular therapeutics, and many additional applications in preclinical models. Parallel progress in radionuclide availability and infrastructure supporting biopharmaceutical manufacturing has accelerated clinical translation. ImmunoPET is poised to provide key information on prognosis, patient selection, and monitoring immune responses to therapy in cancer and beyond.

The Intriguing Landscape of Single-Cell Protein Analysis

Profiling protein expression at single-cell resolution is essential for fundamental biological research (such as cell differentiation and tumor microenvironmental examination) and clinical precision medicine where only a limited number of primary cells are permitted. With the recent advances in engineering, chemistry, and biology, single-cell protein analysis methods are developed rapidly, which enable high-throughput and multiplexed protein measurements in thousands of individual cells. In combination with single cell RNA sequencing and mass spectrometry, single-cell multi-omics analysis can simultaneously measure multiple modalities including mRNAs, proteins, and metabolites in single cells, and obtain a more comprehensive exploration of cellular signaling processes, such as DNA modifications, chromatin accessibility, protein abundance, and gene perturbation. Here, the recent progress and applications of single-cell protein analysis technologies in the last decade are summarized. Current limitations, challenges, and possible future directions in this field are also discussed.

The Current State of Treatment and Future Directions in Cutaneous Malignant Melanoma

Malignant melanoma is the leading cause of death among cutaneous malignancies. While its incidence is increasing, the most recent cancer statistics show a small but clear decrease in mortality rate. This trend reflects the introduction of novel and more effective therapeutic regimens, including the two cornerstones of melanoma therapy: immunotherapies and targeted therapies. Immunotherapies exploit the highly immunogenic nature of melanoma by modulating and priming the patient's own immune system to attack the tumor. Treatments combining immunotherapies with targeted therapies, which disable the carcinogenic products of mutated cancer cells, have further increased treatment efficacy and durability. Toxicity and resistance, however, remain critical challenges to the field. The present review summarizes past treatments and novel therapeutic interventions and discusses current clinical trials and future directions.

PIVOT-12: a phase III study of adjuvant bempegaldesleukin plus nivolumab in resected stage III/IV melanoma at high risk for recurrence

Bempegaldesleukin (BEMPEG: NKTR-214) is an immunostimulatory IL-2 cytokine prodrug engineered to deliver a controlled, sustained and preferential IL-2 pathway signal. Nivolumab (NIVO), a PD-1 inhibitor, has been shown to prolong survival in patients with advanced melanoma and recurrence-free survival in the adjuvant setting. PIVOT-02 showed that BEMPEG plus NIVO was well-tolerated and demonstrated clinical activity as first-line therapy in metastatic melanoma. PIVOT-12 is a randomized, phase III, global, multicenter, open-label study comparing adjuvant therapy with BEMPEG plus NIVO versus NIVO alone in adult and adolescent patients with completely resected cutaneous stage III/IV melanoma at high risk of recurrence. The primary objective is to compare the efficacy, as measured by recurrence-free survival, of BEMPEG plus NIVO versus NIVO.

Engineering interferons and interleukins for cancer immunotherapy

Cytokines are a class of potent immunoregulatory proteins that are secreted in response to various stimuli and act locally to regulate many aspects of human physiology and disease. Cytokines play important roles in cancer initiation, progression, and elimination, and thus, there is a long clinical history associated with the use of recombinant cytokines to treat cancer. However, the use of cytokines as therapeutics has been limited by cytokine pleiotropy, complex biology, poor drug-like properties, and severe dose-limiting toxicities. Nevertheless, cytokines are crucial mediators of innate and adaptive antitumor immunity and have the potential to enhance immunotherapeutic approaches to treat cancer. Development of immune checkpoint inhibitors and combination immunotherapies has reinvigorated interest in cytokines as therapeutics, and a variety of engineering approaches are emerging to improve the safety and effectiveness of cytokine immunotherapy. In this review we highlight recent advances in cytokine biology and engineering for cancer immunotherapy.

Analyzing immune response to engineered hydrogels by hierarchical clustering of inflammatory cell subsets

Understanding the immune response to hydrogel implantation is critical for the design of immunomodulatory biomaterials. To study the progression of inflammation around poly(ethylene glycol) hydrogels presenting Arg-Gly-Asp (RGD) peptides and vascular endothelial growth factor, we used temporal analysis of high-dimensional flow cytometry data paired with intravital imaging, immunohistochemistry, and multiplexed proteomic profiling. RGD-presenting hydrogels created a reparative microenvironment promoting CD206+ cellular infiltration and revascularization in wounded dorsal skin tissue. Unbiased clustering algorithms (SPADE) revealed significant phenotypic transition shifts as a function of the cell-adhesion hydrogel properties. SPADE identified an intermediate macrophage subset functionally regulating in vivo cytokine secretion that was preferentially recruited for RGD-presenting hydrogels, whereas dendritic cell subsets were preferentially recruited to RDG-presenting hydrogels. Last, RGD-presenting hydrogels controlled macrophage functional cytokine secretion to direct polarization and vascularization. Our studies show that unbiased clustering of single-cell data provides unbiased insights into the underlying immune response to engineered materials.

Ipilimumab alone or in combination with nivolumab in patients with advanced melanoma who have progressed or relapsed on PD-1 blockade: clinical outcomes and translational biomarker analyses

BACKGROUND

There are no validated biomarkers that can aid clinicians in selecting who would best benefit from anticytotoxic T lymphocyte-associated antigen 4 monotherapy versus combination checkpoint blockade in patients with advanced melanoma who have progressive disease after programmed death 1 (PD-1) blockade.

METHODS

We conducted a randomized multicenter phase II trial in patients with advanced melanoma. Patients were randomly assigned to receive either 1 mg/kg of nivolumab plus 3 mg/kg of ipilimumab or 3 mg/kg of ipilimumab every 3 weeks for up to four doses. Patients were stratified by histological subtype and prior response to PD-1 therapy. The primary clinical objective was overall response rate by week 18. Translational biomarker analyses were conducted in patients with blood and tissue samples.

RESULTS

Objective responses were seen in 5 of 9 patients in the ipilimumab arm and 2 of 10 patients in the ipilimumab+nivolumab arm; disease control rates (DCRs) (66.7% vs 60.0%) and rates of grade 3-4 adverse events (56% vs 50%) were comparable between arms. In a pooled analysis, patients with clinical benefit (CB), defined as Response Evaluation Criteria in Solid Tumors response or progression-free for 6 months, showed increased circulating CD4+ T cells with higher polyfunctionality and interferon gamma production following treatment. Tumor profiling revealed enrichment of NRAS mutations and activation of transcriptional programs associated with innate and adaptive immunity in patients with CB.

CONCLUSIONS

In patients with advanced melanoma that previously progressed on PD-1 blockade, objective responses were seen in both arms, with comparable DCRs. Findings from biomarker analyses provided hypothesis-generating signals for validation in future studies of larger patient cohorts.

TRIAL REGISTRATION NUMBER

NCT02731729.

Identification and Validation of New Interleukin-2 Ligands Using DNA-Encoded Libraries

Interleukin-2 (IL2) is a pro-inflammatory cytokine that plays a crucial role in immunity, which is increasingly being used for therapeutic applications. There is growing interest in developing IL2-based therapeutics which do not interact with the alpha subunit of the IL2 receptor (CD25) as this protein is primarily found on immunosuppressive regulatory T cells (T_regs). Screenings of a new DNA-encoded library, comprising 669,240 members, provided a novel series of IL2 ligands, subsequently optimized by medicinal chemistry. One of these molecules (compound 18) bound to IL2 with a dissociation constant of 0.34 μM was able to form a kinetically stable complex with IL2 in size-exclusion chromatography and recognized the CD25-binding site as evidenced by competition experiments with the NARA1 antibody. Compound 18 and other members of the series may represent the starting point for the discovery of potent small-molecule modulators of IL2 activity, abrogating the binding to CD25.

Single-cell polyfunctional proteomics of CD4 cells from patients with AML predicts responses to anti-PD-1-based therapy

Acute myeloid leukemia (AML) remains a difficult disease to treat disease. In a phase 2 clinical trial in patients with relapsed/refractory AML, combining the hypomethylating agent, azacitidine, with the PD-1 checkpoint inhibitor, nivolumab, demonstrated encouraging response rates (33%), median event-free, and overall survival, compared with a historical cohort of contemporary patients treated with azacitidine-based therapies, with an acceptable safety profile. Biomarkers of response are yet to be determined. In this study, we leveraged a multiplexed immune assay to assess the functional states of CD4+ and CD8+ cells at a single-cell level in pretherapy bone marrows in 16 patients with relapsed/refractory AML treated with azacitidine/nivolumab. Effector CD4+ but not CD8+ cells had distinct polyfunctional groups and were associated with responses and better outcomes. Further evaluation of the polyfunctional strength index composition across cell types revealed that interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) were the major drivers of enhanced polyfunctionality index of pretherapy CD4+ subset, whereas Granzyme B, IFN-γ, MIP-1b, and TNF-α drove the nonsignificantly enhanced pretreatment Polyfunctional Strength Index of CD8+ subset in the responders. Single-cell polyfunctional assays were predictive of response in AML and may have a potential role as a biomarker in the wider sphere of immunotherapy.

Interleukin 2-Based Fusion Proteins for the Treatment of Cancer

Interleukin 2 (IL-2) plays a fundamental role in both immune activation and tolerance and has revolutionized the field of cancer immunotherapy since its discovery. The ability of IL-2 to mediate tumor regression in preclinical and clinical settings led to FDA approval for its use in the treatment of metastatic renal cell carcinoma and metastatic melanoma in the 1990s. Although modest success is observed in the clinic, cancer patients receiving IL-2 therapy experience a wide array of side effects ranging from flu-like symptoms to life-threatening conditions such as vascular leak syndrome. Over the past three decades, efforts have focused on circumventing IL-2-related toxicities by engineering methods to localize IL-2 to the tumor or secondary lymphoid tissue, preferentially activate CD8⁺ T cells and NK cells, and alter pharmacokinetic properties to increase bioavailability. This review summarizes the various IL-2-based strategies that have emerged, with a focus on chimeric fusion methods.

4-1BB and optimized CD28 co-stimulation enhances function of human mono-specific and bi-specific third-generation CAR T cells

Background

Co-stimulatory signals regulate the expansion, persistence, and function of chimeric antigen receptor (CAR) T cells. Most studies have focused on the co-stimulatory domains CD28 or 4-1BB. CAR T cell persistence is enhanced by 4-1BB co-stimulation leading to nuclear factor kappa B (NF-κB) signaling, while resistance to exhaustion is enhanced by mutations of the CD28 co-stimulatory domain.

Methods

We hypothesized that a third-generation CAR containing 4-1BB and CD28 with only PYAP signaling motif (mut06) would provide beneficial aspects of both. We designed CD19-specific CAR T cells with either 4-1BB or mut06 together with the combination of both and evaluated their immune-phenotype, cytokine secretion, real-time cytotoxic ability and polyfunctionality against CD19-expressing cells. We analyzed lymphocyte-specific protein tyrosine kinase (LCK) recruitment by the different constructs by immunoblotting. We further determined their ability to control growth of Raji cells in NOD scid gamma (NSG) mice. We also engineered bi-specific CARs against CD20/CD19 combining 4-1BB and mut06 and performed repeated in vitro antigenic stimulation experiments to evaluate their expansion, memory phenotype and phenotypic (PD1⁺CD39⁺) and functional exhaustion. Bi-specific CAR T cells were transferred into Raji or Nalm6-bearing mice to study their ability to eradicate CD20/CD19-expressing tumors.

Results

Co-stimulatory domains combining 4-1BB and mut06 confers CAR T cells with an increased central memory phenotype, expansion, and LCK recruitment to the CAR. This enhanced function was dependent on the positioning of the two co-stimulatory domains. A bi-specific CAR targeting CD20/CD19, incorporating 4-1BB and mut06 co-stimulation, showed enhanced antigen-dependent in vitro expansion with lower exhaustion-associated markers. Bi-specific CAR T cells exhibited improved in vivo antitumor activity with increased persistence and decreased exhaustion.

Conclusion

These results demonstrate that co-stimulation combining 4-1BB with an optimized form of CD28 is a valid approach to optimize CAR T cell function. Cells with both mono-specific and bi-specific versions of this design showed enhanced in vitro and in vivo features such as expansion, persistence and resistance to exhaustion. Our observations validate the approach and justify clinical studies to test the efficacy and safety of this CAR in patients.

Single-Cell Multiomics Analysis for Drug Discovery

Given the heterogeneity seen in cell populations within biological systems, analysis of single cells is necessary for studying mechanisms that cannot be identified on a bulk population level. There are significant variations in the biological and physiological function of cell populations due to the functional differences within, as well as between, single species as a result of the specific proteome, transcriptome, and metabolome that are unique to each individual cell. Single-cell analysis proves crucial in providing a comprehensive understanding of the biological and physiological properties underlying human health and disease. Omics technologies can help to examine proteins (proteomics), RNA molecules (transcriptomics), and the chemical processes involving metabolites (metabolomics) in cells, in addition to genomes. In this review, we discuss the value of multiomics in drug discovery and the importance of single-cell multiomics measurements. We will provide examples of the benefits of applying single-cell omics technologies in drug discovery and development. Moreover, we intend to show how multiomics offers the opportunity to understand the detailed events which produce or prevent disease, and ways in which the separate omics disciplines complement each other to build a broader, deeper knowledge base.

Enhancing adoptive CD8 T cell therapy by systemic delivery of tumor associated antigens

Adoptive T-cell transfer (ACT) offers a curative therapeutic option for subsets of melanoma and hematological cancer patients. To increase response rates and broaden the applicability of ACT, it is necessary to improve the post-infusion performance of the transferred T cells. The design of improved treatment strategies includes transfer of cells with a less differentiated phenotype. Such T cell subsets have high proliferative potential but require stimulatory signals in vivo to differentiate into tumor-reactive effector T cells. Thus, combination strategies are needed to support the therapeutic implementation of less differentiated T cells. Here we show that systemic delivery of tumor-associated antigens (TAAs) facilitates in vivo priming and expansion of previously non-activated T cells and enhance the cytotoxicity of activated T cells. To achieve this in vivo priming, we use flexible delivery vehicles of TAAs and a TLR7/8 agonist. Contrasting subcutaneous delivery systems, these vehicles accumulate TAAs in the spleen, thereby achieving close proximity to both cross-presenting dendritic cells and transferred T cells, resulting in robust T-cell expansion and anti-tumor reactivity. This TAA delivery platform offers a strategy to safely potentiate the post-infusion performance of T cells using low doses of antigen and TLR7/8 agonist, and thereby enhance the effect of ACT.

Clinical translation of immunomodulatory therapeutics

Immunomodulatory therapeutics represent a unique class of drug products that have tremendous potential to rebalance malfunctioning immune systems and are quickly becoming one of the fastest-growing areas in the pharmaceutical industry. For these drugs to become mainstream medicines, they must provide greater therapeutic benefit than the currently used treatments without causing severe toxicities. Immunomodulators, cell-based therapies, antibodies, and viral therapies have all achieved varying amounts of success in the treatment of cancers and/or autoimmune diseases. However, many challenges related to precision dosing, off-target effects, and manufacturing hurdles will need to be addressed before we see widespread adoption of these therapies in the clinic. This review provides a perspective on the progress of immunostimulatory and immunosuppressive therapies to date and discusses the opportunities and challenges for clinical translation of the next generation of immunomodulatory therapeutics.

In Vivo Cell Tracking Using PET: Opportunities and Challenges for Clinical Translation in Oncology

Cell therapy is a rapidly evolving field involving a wide spectrum of therapeutic cells for personalised medicine in cancer. In vivo imaging and tracking of cells can provide useful information for improving the accuracy, efficacy, and safety of cell therapies. This review focuses on radiopharmaceuticals for the non-invasive detection and tracking of therapeutic cells using positron emission tomography (PET). A range of approaches for imaging therapeutic cells is discussed: Direct ex vivo labelling of cells, in vivo indirect labelling of cells by utilising gene reporters, and detection of specific antigens expressed on the target cells using antibody-based radiopharmaceuticals (immuno-PET). This review examines the evaluation of PET imaging methods for therapeutic cell tracking in preclinical cancer models, their role in the translation into patients, first-in-human studies, as well as the translational challenges involved and how they can be overcome.