Single-cell CRISPR screens in vivo map T cell fate regulomes in cancer.

CD8+ cytotoxic T cells (CTLs) orchestrate antitumour immunity and exhibit inherent heterogeneity1,2, with precursor exhausted T (Tpex) cells but not terminally exhausted T (Tex) cells capable of responding to existing immunotherapies3-7. The gene regulatory network that underlies CTL differentiation and whether Tex cell responses can be functionally reinvigorated are incompletely understood. Here we systematically mapped causal gene regulatory networks using single-cell CRISPR screens in vivo and discovered checkpoints for CTL differentiation. First, the exit from quiescence of Tpex cells initiated successive differentiation into intermediate Tex cells. This process is differentially regulated by IKAROS and ETS1, the deficiencies of which dampened and increased mTORC1-associated metabolic activities, respectively. IKAROS-deficient cells accumulated as a metabolically quiescent Tpex cell population with limited differentiation potential following immune checkpoint blockade (ICB). Conversely, targeting ETS1 improved antitumour immunity and ICB efficacy by boosting differentiation of Tpex to intermediate Tex cells and metabolic rewiring. Mechanistically, TCF-1 and BATF are the targets for IKAROS and ETS1, respectively. Second, the RBPJ-IRF1 axis promoted differentiation of intermediate Tex to terminal Tex cells. Accordingly, targeting RBPJ enhanced functional and epigenetic reprogramming of Tex cells towards the proliferative state and improved therapeutic effects and ICB efficacy. Collectively, our study reveals that promoting the exit from quiescence of Tpex cells and enriching the proliferative Tex cell state act as key modalities for antitumour effects and provides a systemic framework to integrate cell fate regulomes and reprogrammable functional determinants for cancer immunity.

Ranitidine as an adjuvant regulates macrophage polarization and activates CTLs through the PI3K-Akt2 signaling pathway.

Adjuvants are an indispensable component of vaccines, but there are few adjuvants for human vaccines. H2 receptor blockers, inhibiting gastric acid secretion, have immune enhancement effects. Ranitidine (RAN) is a water-soluble H2 receptor blocker, and whether it has an immune-enhancing effect is still unknown. In this study, flow cytometry, western blotting, and immunofluorescence methods were used to analyze whether RAN could activate macrophage polarization to the M1 phenotype in vivo and in vitro. Here, we found that the M1 inflammatory cytokine levels and surface markers in RAW264.7 cells were upregulated by NF-κB activation, possibly through the PI3K-Akt2 signaling pathway, after RAN treatment. Endocytic function was also enhanced by feedback regulation of Akt2/GSK3ß/Dynmin1 signaling. Furthermore, to evaluate the adjuvant function of RAN, we used OVA plus RAN as a vaccine to inhibit the growth of B16-OVA tumors in mice. We also found that in the RAN adjuvant group, macrophage polarization to M1, Th1 cell differentiation, and cytotoxic T lymphocyte (CTL) activation were significantly upregulated. The tumor growth of mice was inhibited, and the survival rate of mice was significantly improved. This study provides new evidence for the mechanism by which RAN activates the immune response and is expected to provide a new strategy for the research and development of tumor vaccine adjuvants.

Targeting necroptosis in muscle fibers ameliorates inflammatory myopathies.

Muscle cell death in polymyositis is induced by CD8+ cytotoxic T lymphocytes. We hypothesized that the injured muscle fibers release pro-inflammatory molecules, which would further accelerate CD8+ cytotoxic T lymphocytes-induced muscle injury, and inhibition of the cell death of muscle fibers could be a novel therapeutic strategy to suppress both muscle injury and inflammation in polymyositis. Here, we show that the pattern of cell death of muscle fibers in polymyositis is FAS ligand-dependent necroptosis, while that of satellite cells and myoblasts is perforin 1/granzyme B-dependent apoptosis, using human muscle biopsy specimens of polymyositis patients and models of polymyositis in vitro and in vivo. Inhibition of necroptosis suppresses not only CD8+ cytotoxic T lymphocytes-induced cell death of myotubes but also the release of inflammatory molecules including HMGB1. Treatment with a necroptosis inhibitor or anti-HMGB1 antibodies ameliorates myositis-induced muscle weakness as well as muscle cell death and inflammation in the muscles. Thus, targeting necroptosis in muscle cells is a promising strategy for treating polymyositis providing an alternative to current therapies directed at leukocytes.

Cordycepin prevents and ameliorates experimental autoimmune encephalomyelitis by inhibiting leukocyte infiltration and reducing neuroinflammation.

Multiple sclerosis (MS) is a neuroinflammatory autoimmune disease characterized by multifocal perivascular infiltration of immune cells in the central nervous system (CNS). Cordycepin (3'-deoxyadenosine), an adenosine analogue initially extracted from the fungus Cordyceps militarisa, is one of the candidates that has multiple actions. We investigated that cordycepin attenuated the activation of LPS-induced mouse bone marrow-derived dendritic cells (BMDCs) and human monocyte-derived dendritic cells (MoDCs) through the inhibition of the AKT, ERK, NFκB, and ROS pathways and impaired the migration of BMDCs through the downregulation of adhesion molecules and chemokine receptors in vitro. In experimental autoimmune encephalomyelitis (EAE) model, preventive treatment with cordycepin decreased the expression of trafficking factors in the CNS, inhibited the secretion of inflammatory cytokines (IFN-γ, IL-6, TNF-α, and IL-17), and attenuated disease symptoms. A chemokine array indicated that cordycepin treatment reversed the high levels of CCL6, PARRES2, IL-16, CXCL10, and CCL12 in the brain and spinal cord of EAE mice, consistent with the RNA-seq data. Moreover, cordycepin suppressed the release of neuroinflammatory cytokines by activated microglial cells, macrophages, Th17 cells, Tc1 cells, and Th1 cells in vitro. Furthermore, cordycepin treatment exerted therapeutic effects on attenuating the disease severity in the early disease onset stage and late disease progression stage. Our study suggests that cordycepin treatment may not only prevent the occurrence of MS by inhibiting DC activation and migration but also potentially ameliorates the progression of MS by reducing neuroinflammation, which may provide insights into the development of new approaches for the treatment of MS.

Intrapleural Injection of Anti-PD1 Antibody: A Novel Management of Malignant Pleural Effusion.

Background: Malignant tumors accompanied with malignant pleural effusion (MPE) often indicate poor prognosis. The therapeutic effect and mechanism of intrapleural injection of anti-programmed cell death protein 1 (PD1) on MPE need to be explored. Methods: A preclinical MPE mouse model and a small clinical study were used to evaluate the effect of intrapleural injection of anti-PD1 antibody. The role of immune cells was observed via flow cytometry, RNA-sequencing, quantitative PCR, western blot, immunohistochemistry, and other experimental methods. Results: Intrathoracic injection of anti-PD1 monoclonal antibody (mAb) has significantly prolonged the survival time of mice (P = 0.0098) and reduced the amount of effusion (P = 0.003) and the number of cancer nodules (P = 0.0043). Local CD8+ T cells participated in intrapleural administration of anti-PD1 mAb. The proportion of CD69+, IFN-γ+, and granzyme B+ CD8+ T cells in the pleural cavity was increased, and the expression of TNF-α and IL-1ß in MPE also developed significantly after injection. Local injection promoted activation of the CCL20/CCR6 pathway in the tumor microenvironment and further elevated the expression of several molecules related to lymphocyte activation. Clinically, the control rate of intrathoracic injection of sintilimab (a human anti-PD1 mAb) for 10 weeks in NSCLC patients with MPE was 66.7%. Local injection improved the activity and function of patients' local cytotoxic T cells (CTLs). Conclusions: Intrapleural injection of anti-PD1 mAb could control malignant pleural effusion and the growth of cancer, which may be achieved by enhancing local CTL activity and cytotoxicity.

Diminished Peripheral CD29hi Cytotoxic CD4+ T Cells Are Associated With Deleterious Effects During SIV Infection.

Cytotoxic CD4+ T cells (CD4+ CTLs) limit HIV pathogenesis, as evidenced in elite controllers (a subset of individuals who suppress the virus without the need for therapy). CD4+ CTLs have also been shown to kill HIV-infected macrophages. However, little is known about their contribution towards HIV persistence, how they are affected following exposure to immune modulators like morphine, and what factors maintain their frequencies and function. Further, the lack of robust markers to identify CD4+ CTLs in various animal models limits understanding of their role in HIV pathogenesis. We utilized various PBMC samples obtained from SIV infected and cART treated rhesus macaques exposed to morphine or saline and subjected to flow cytometry evaluations. Thereafter, we compared and correlated the expression of CD4+ CTL-specific markers to viral load and viral reservoir estimations in total CD4+ T cells. We found that CD29 could be reliably used as a marker to identify CD4+ CTLs in rhesus macaques since CD29hi CD4+ T cells secrete higher cytotoxic and proinflammatory cytokines following PMA/ionomycin or gag stimulation. In addition, this immune cell subset was depleted during untreated SIV infection. Strikingly, we also observed that early initiation of cART reconstitutes depleted CD29hi CD4+ T cells and restores their function. Furthermore, we noted that morphine exposure reduced the secretion of proinflammatory cytokines/cytotoxic molecules in CD29hi CD4+ T cells. Lastly, increased functionality of CD29hi CD4+ T cells as depicted by elevated levels of either IL-21 or granzyme B hi T Bet+ gag specific responses were linked to limiting the size of the replication-competent reservoir during cART treatment. Collectively, our data suggest that CD4+ CTLs are crucial in limiting SIV pathogenesis and persistence.

Quantitative Analyses Reveal How Hypoxia Reconfigures the Proteome of Primary Cytotoxic T Lymphocytes.

Metabolic and nutrient-sensing pathways play an important role in controlling the efficacy of effector T cells. Oxygen is a critical regulator of cellular metabolism. However, during immune responses T cells must function in oxygen-deficient, or hypoxic, environments. Here, we used high resolution mass spectrometry to investigate how the proteome of primary murine CD8+ cytotoxic T lymphocytes (CTLs) is reconfigured in response to hypoxia in vitro. We identified and quantified over 7,600 proteins and discovered that hypoxia increased the abundance of a selected number of proteins in CTLs. This included glucose transporters, metabolic enzymes, transcription factors, cytolytic effector molecules, checkpoint receptors and adhesion molecules. While some of these proteins may augment the effector functions of CTLs, others may limit their cytotoxicity. Moreover, we determined that hypoxia could inhibit IL-2-induced proliferation cues and antigen-induced pro-inflammatory cytokine production in CTLs. These data provide a comprehensive resource for understanding the magnitude of the CTL response to hypoxia and emphasise the importance of oxygen-sensing pathways for controlling CD8+ T cells. Additionally, this study provides new understanding about how hypoxia may promote the effector function of CTLs, while contributing to their dysfunction in some contexts.

PI3Kγδ inhibitor plus radiation enhances the antitumour immune effect of PD-1 blockade in syngenic murine breast cancer and humanised patient-derived xenograft model.

INTRODUCTION: We hypothesised that the combined use of radiation therapy and a phosphoinositide 3-kinaseγδ inhibitor to reduce immune suppression would enhance the efficacy of an immune checkpoint inhibitor. METHODS: Murine breast cancer cells (4T1) were grown in both immune-competent and -deficient BALB/c mice, and tumours were irradiated by 3 fractions of 24 Gy. A PD-1 blockade and a phosphoinositide 3-kinase (PI3K)γδ inhibitor were then administered every other day for 2 weeks. The same experiments were performed in humanised patient-derived breast cancer xenograft model and its tumour was sequenced to identify immune-related pathways and profile infiltrated immune cells. Transcriptomic and clinical data were acquired from The Cancer Genome Atlas pan-cancer cohort, and the deconvolution algorithm was used to profile immune cell repertoire. RESULTS: Using a PI3Kγδ inhibitor, radiation therapy (RT) and PD-1 blockade significantly delayed primary tumour growth, boosted the abscopal effect and improved animal survival. RT significantly increased CD8+cytotoxic T-cell fractions, immune-suppressive regulatory T cells (Tregs), myeloid-derived suppressor cells and M2 tumour-associated macrophages (TAMs). However, the PI3Kγδ inhibitor significantly lowered the proportions of Tregs, myeloid-derived suppressor cells and M2 TAMs, achieving dramatic gains in splenic, nodal, and tumour CD8+ T-cell populations after triple combination therapy. In a humanised patient-derived breast cancer xenograft model, triple combination therapy significantly delayed tumour growth and decreased immune-suppressive pathways. In The Cancer Genome Atlas cohort, high Treg/CD8+ T cell and M2/M1 TAM ratios were associated with poor overall patient survival. CONCLUSION: These findings indicate PI3Kγ and PI3Kδ are clinically relevant targets in an immunosuppressive TME, and combining PI3Kγδ inhibitor, RT and PD-1 blockade may overcome the therapeutic resistance of immunologically cold tumours. SYNOPSIS: Combining PI3Kγδ inhibitor, RT, and PD-1 blockade may be a viable clinical approach, helping to overcome the therapeutic resistance of immunologically cold tumours such as breast cancer.

LN Monocytes Limit DC-Poly I:C Induced Cytotoxic T Cell Response via IL-10 and Induction of Suppressor CD4 T Cells.

Every immune response has accelerators and brakes. Depending on the pathogen or injury, monocytes can play either role, promoting or resolving immunity. Poly I:C, a potent TLR3 ligand, licenses cross-presenting dendritic cells (DC1) to accelerate a robust cytotoxic T cells response against a foreign antigen. Poly I:C thus has promise as an adjuvant in cancer immunotherapy and viral subunit vaccines. Like DC1s, monocytes are also abundant in the LNs. They may act as either immune accelerators or brakes, depending on the inflammatory mediator they encounter. However, little is known about their contribution to adaptive immunity in the context of antigen and Poly I:C. Using monocyte-deficient and chimeric mice, we demonstrate that LN monocytes indirectly dampen a Poly I:C induced antigen-specific cytotoxic T cell response, exerting a "braking" function. This effect is mediated by IL-10 production and induction of suppressor CD4+ T cells. In a metastatic melanoma model, we show that a triple-combination prophylactic treatment consisting of anti-IL-10, tumor peptides and Poly I:C works because removing IL-10 counteracts the monocytic brake, resulting in significantly fewer tumors compared to mice treated with tumor peptides and Poly I:C alone. Finally, in human LN tissue, we observed that monocytes (unlike DCs) express high levels of IL-10, suggesting that anti-IL-10 may be an important addition to treatments. Overall, our data demonstrates that LN monocytes regulate the induction of a robust DC1-mediated immune response. Neutralization of either IL-10 or monocytes can augment Poly I:C-based treatments and enhance T cell cytotoxicity.

Immunotherapy Strategy Targeting Programmed Cell Death Ligand 1 and CD73 with Macrophage-Derived Mimetic Nanovesicles to Treat Bladder Cancer.

Combination immunotherapy is a promising strategy to remove the inhibitory effect of the tumor microenvironment on immune effector cells, improving the efficacy of immune checkpoint inhibitor treatment in bladder cancer. However, it is challenging to deliver multiple drugs to the tumor tissue effectively and simultaneously to ensure optimal therapeutic effects. Macrophage-derived exosome-mimetic nanovesicles (EMVs) were designed and validated as a nanoplatform for coloading and delivery of the CD73 inhibitor (AB680) and the monoclonal antibody to programmed cell death ligand 1 (aPDL1). The tumor-targeting, biosafety, and therapeutic effects of these nanocomplexes (AB680@EMVs-aPDL1), as a combined immunotherapy strategy for bladder cancer, were assessed in vitro and in vivo. Our results indicate that the nanodrug system was highly stable, provided adequate biosafety, and enhanced tumor targeting in a mouse model of bladder cancer. Moreover, the CD73 inhibitor reduced extracellular adenosine production, and the combination therapy significantly promoted the activation and infiltration of cytotoxic T-lymphocytes, which helped to optimally suppress tumor growth and extend median survival in vivo. Therefore, using EMVs to deliver a combination of aPDL1 and the CD73 inhibitor may be a useful combined immunotherapy strategy for treating bladder cancer.

A nanounit strategy reverses immune suppression of exosomal PD-L1 and is associated with enhanced ferroptosis.

In addition to increasing the expression of programmed death-ligand 1 (PD-L1), tumor cells can also secrete exosomal PD-L1 to suppress T cell activity. Emerging evidence has revealed that exosomal PD-L1 resists immune checkpoint blockade, and may contribute to resistance to therapy. In this scenario, suppressing the secretion of tumor-derived exosomes may aid therapy. Here, we develop an assembly of exosome inhibitor (GW4869) and ferroptosis inducer (Fe3+) via amphiphilic hyaluronic acid. Cooperation between the two active components in the constructed nanounit induces an anti-tumor immunoresponse to B16F10 melanoma cells and stimulates cytotoxic T lymphocytes and immunological memory. The nanounit enhances the response to PD-L1 checkpoint blockade and may represent a therapeutic strategy for enhancing the response to this therapy.

Thermal-sensitive lipid nanoparticles potentiate anti-PD therapy through enhancing drug penetration and T lymphocytes infiltration in metastatic tumor.

The response rate of anti-PD therapy in most cancer patients remains low. Therapeutic drug and tumor-infiltrating lymphocytes (TILs) are usually obstructed by the stromal region within tumor microenvironment (TME) rather than distributed around tumor cells, thus unable to induce the immune response of cytotoxic T cells. Here, we constructed the cationic thermosensitive lipid nanoparticles IR780/DPPC/BMS by introducing cationic NIR photosensitizer IR-780 iodide (IR780) modified lipid components, thermosensitive lipid DPPC and PD-1/PD-L1 inhibitor BMS202 (BMS). Upon laser irradiation, IR780/DPPC/BMS penetrated into deep tumor, and reduced cancer-associated fibroblasts (CAFs) around tumor cells to remodel the spatial distribution of TILs in TME. Interestingly, the cationic IR780/DPPC/BMS could capture released tumor-associated antigens (TAAs), thereby enhancing the antigen-presenting ability of DCs to activate cytotoxic T lymphocytes. Moreover, IR780/DPPC/BMS initiated gel-liquid crystal phase transition under laser irradiation, accelerating the disintegration of lipid bilayer structure and leading to the responsive release of BMS, which would reverse the tumor immunosuppression state by blocking PD-1/PD-L1 pathway for a long term. This combination treatment can synergistically exert the antitumor immune response and inhibit the tumor growth and metastasis.

Dual targeting of lymphocyte homing and retention through α4ß7 and αEß7 inhibition in inflammatory bowel disease.

Anti-integrins are therapeutically effective for inflammatory bowel disease, yet the relative contribution of α4ß7 and αEß7 to gut lymphocyte trafficking is not fully elucidated. Here, we evaluate the effect of α4ß7 and αEß7 blockade using a combination of murine models of gut trafficking and longitudinal gene expression analysis in etrolizumab-treated patients with Crohn's disease (CD). Dual blockade of α4ß7 and αEß7 reduces CD8+ T cell accumulation in the gut to a greater extent than blockade of either integrin alone. Anti-αEß7 reduces epithelial:T cell interactions and promotes egress of activated T cells from the mucosa into lymphatics. Inflammatory gene expression is greater in human intestinal αEß7+ T cells. Etrolizumab-treated patients with CD display a treatment-specific reduction in inflammatory and cytotoxic intraepithelial lymphocytes (IEL) genes. Concurrent blockade of α4ß7 and αEß7 promotes reduction of cytotoxic IELs and inflammatory T cells in the gut mucosa through a stepwise inhibition of intestinal tissue entry and retention.

A new PD-1-specific nanobody enhances the antitumor activity of T-cells in synergy with dendritic cell vaccine.

Despite the many successes and opportunities presented by PD-1 blockade in cancer therapies, anti-PD-1 monoclonal antibodies still face multiple challenges. Herein we report a strategy based on a nanobody (Nb) to circumvent these obstacles. A new PD-1-blocking Nb (PD-1 Nb20) in combination with tumor-specific dendritic cell (DC)/tumor-fusion cell (FC) vaccine that aims to improve the activation, proliferation, cytokine secretion, and tumor cell cytotoxicity of CD8+ T-cells. This combination was found to effectively enhance the in vitro cytotoxicity of CD8+ T-cells to kill human non-small cell lung cancer (NSCLC) HCC827 cells, hepatocellular carcinoma (HCC) HepG2 cells, and tongue squamous cell carcinoma (TSCC) Tca8113 cells. Moreover, CD8+ T-cells pre-treated with PD-1 Nb20 and tumor-specific DC/tumor-FCs significantly suppressed the growth of NSCLC-, HCC- and TSCC-derived xenograft tumors and prolonged the survival of tumor-bearing mice, through promoting T-cell infiltration to kill tumor cells and inhibiting tumor angiogenesis. These data demonstrate that PD-1 Nb20 in synergy with DC/tumor-FC vaccine augment the broad spectrum of antitumor activity of CD8+ T-cells, providing an alternative and promising immunotherapeutic strategy for tumor patients who are T-cell-dysfunctional or not sensitive to anti-PD-1 therapy.

Design, synthesis, and pharmacological evaluation of sinomenine derivatives on rings A and C: Novel compounds screening for aplastic anemia targeting on cytotoxic T lymphocyte.

Cytotoxic T lymphocyte (CTL), a key effector cell in aplastic anemia (AA) immune injury, is shown to be a potential target for AA drug therapy. However, there is no candidate for this target till now. Oriented by the inhibition activity of CTL and macrophage derived nitric oxide (NO), a series of novel sinomenine derivatives on rings A and C are designed, synthesized and screened. Among them, compound 3a demonstrates the best inhibitory activity on CTL with an IC50 value of 2.3 µM, and a 97.1% inhibiton rate on macrophage NO production without significant cytotoxicity. Further, compound 3a exhibits substantial therapeutic efficacy on immune-mediated BM failure in AA model mice by improving the symptoms of anemia and the function of BM hematopoiesis, and shows more advantages in life quality improving than cyclosporine A (CsA). Its efficacy on AA at least partly comes from targeting on activated cluster of differentiation (CD)8+ T cell. Additionally, 3a also shows much less toxicity (LD50 > 10.0 g/kg) than sinomenine (LD50 = 1.1 g/kg) in preliminary acute toxicity assessment in mice, and has a low risk to inhibit hERG to cause cardiotoxicity. These results indicate that compound 3a merits further investigation for AA treatment by targeting on CTL.

Development of combination adjuvant for efficient T cell and antibody response induction against protein antigen.

Most current clinical vaccines work primarily by inducing the production of neutralizing antibodies against pathogens. Vaccine adjuvants that efficiently induce T cell responses to protein antigens need to be developed. In this study, we developed a new combination adjuvant consisting of 1,2-dioleoyl-3-trimethylammonium propane (DOTAP), D35, and an aluminum salt. Among the various combinations tested, the DOTAP/D35/aluminum salt adjuvant induced strong T cell and antibody responses against the model protein antigen with a single immunization. Adjuvant component and model antigen interaction studies in vitro also revealed that the strong mutual interactions among protein antigens and other components were one of the important factors for this efficient immune induction by the novel combination adjuvant. In addition, in vivo imaging of the antigen distribution suggested that the DOTAP component in the combination adjuvant formulation elicited transient antigen accumulation at the draining lymph nodes, possibly by antigen uptake DC migration. These results indicate the potential of the new combination adjuvant as a promising vaccine adjuvant candidate to treat infectious diseases and cancers.

Immunogenic camptothesome nanovesicles comprising sphingomyelin-derived camptothecin bilayers for safe and synergistic cancer immunochemotherapy.

Despite the enormous therapeutic potential of immune checkpoint blockade (ICB), it benefits only a small subset of patients. Some chemotherapeutics can switch 'immune-cold' tumours to 'immune-hot' to synergize with ICB. However, safe and universal therapeutic platforms implementing such immune effects remain scarce. We demonstrate that sphingomyelin-derived camptothecin nanovesicles (camptothesomes) elicit potent granzyme-B- and perforin-mediated cytotoxic T lymphocyte (CTL) responses, potentiating PD-L1/PD-1 co-blockade to eradicate subcutaneous MC38 adenocarcinoma with developed memory immunity. In addition, camptothesomes improve the pharmacokinetics and lactone stability of camptothecin, avoid systemic toxicities, penetrate deeply into the tumour and outperform the antitumour efficacy of Onivyde. Camptothesome co-load the indoleamine 2,3-dioxygenase inhibitor indoximod into its interior using the lipid-bilayer-crossing capability of the immunogenic cell death inducer doxorubicin, eliminating clinically relevant advanced orthotopic CT26-Luc tumours and late-stage B16-F10-Luc2 melanoma, and achieving complete metastasis remission when combined with ICB and folate targeting. The sphingomyelin-derived nanotherapeutic platform and doxorubicin-enabled transmembrane transporting technology are generalizable to various therapeutics, paving the way for transformation of the cancer immunochemotherapy paradigm.

Iron Released after Cryo-Thermal Therapy Induced M1 Macrophage Polarization, Promoting the Differentiation of CD4+ T Cells into CTLs.

Macrophages play critical roles in both innate and adaptive immunity and are known for their high plasticity in response to various external signals. Macrophages are involved in regulating systematic iron homeostasis and they sequester iron by phagocytotic activity, which triggers M1 macrophage polarization and typically exerts antitumor effects. We previously developed a novel cryo-thermal therapy that can induce the mass release of tumor antigens and damage-associated molecular patterns (DAMPs), promoting M1 macrophage polarization. However, that study did not examine whether iron released after cryo-thermal therapy induced M1 macrophage polarization; this question still needed to be addressed. We hypothesized that cryo-thermal therapy would cause the release of a large quantity of iron to augment M1 macrophage polarization due to the disruption of tumor cells and blood vessels, which would further enhance antitumor immunity. In this study, we investigated iron released in primary tumors, the level of iron in splenic macrophages after cryo-thermal therapy and the effect of iron on macrophage polarization and CD4+ T cell differentiation in metastatic 4T1 murine mammary carcinoma. We found that a large amount of iron was released after cryo-thermal therapy and could be taken up by splenic macrophages, which further promoted M1 macrophage polarization by inhibiting ERK phosphorylation. Moreover, iron promoted DC maturation, which was possibly mediated by iron-induced M1 macrophages. In addition, iron-induced M1 macrophages and mature DCs promoted the differentiation of CD4+ T cells into the CD4 cytolytic T lymphocytes (CTL) subset and inhibited differentiation into Th2 and Th17 cells. This study explains the role of iron in cryo-thermal therapy-induced antitumor immunity from a new perspective.

Second Near-Infrared Light-Activatable Polymeric Nanoantagonist for Photothermal Immunometabolic Cancer Therapy.

Immunometabolic modulation offers new opportunities to treat cancers as it is highly associated with cancer progression and immunosuppressive microenvironment. However, traditional regimens using nonselective small-molecule immunomodulators lead to the off-target adverse effects and insufficient therapeutic outcomes. Herein a second near-infrared (NIR-II) photothermally activatable semiconducting polymeric nanoantagonist (ASPA) for synergistic photothermal immunometabolic therapy of cancer is reported. ASPA backbone is obtained by conjugating vipadenant, an antagonist to adenosine A2A receptor, onto NIR-II light-absorbing semiconducting polymer via an azo-based thermolabile linker. Under deep-penetrating NIR-II photoirradiation, ASPA induces tumor thermal ablation and subsequently immunogenic cell death, triggers the cleavage of thermolabile linker, and releases the antagonist to block the immunosuppressive adenosinergic pathway. Such a remotely controlled immunometabolic regulation potentiates cytotoxic T cell functions while suppresses regulatory T cell activities, leading to efficient primary tumor inhibition, pulmonary metastasis prevention, and long-term immunological memory. Thereby, this work provides a generic polymeric approach for precise spatiotemporal regulation of cancer immunometabolism.

High Glucose Enhances Cytotoxic T Lymphocyte-Mediated Cytotoxicity.

Cytotoxic T lymphocytes (CTLs) are key players to eliminate tumorigenic or pathogen-infected cells using lytic granules (LG) and Fas ligand (FasL) pathways. Depletion of glucose leads to severely impaired cytotoxic function of CTLs. However, the impact of excessive glucose on CTL functions still remains largely unknown. Here we used primary human CD8+ T cells, which were stimulated by CD3/CD28 beads and cultured in medium either containing high glucose (HG, 25 mM) or normal glucose (NG, 5.6 mM). We found that in HG-CTLs, glucose uptake and glycolysis were enhanced, whereas proliferation remained unaltered. Furthermore, CTLs cultured in HG exhibited an enhanced CTL killing efficiency compared to their counterparts in NG. Unexpectedly, expression of cytotoxic proteins (perforin, granzyme A, granzyme B and FasL), LG release, cytokine/cytotoxic protein release and CTL migration remained unchanged in HG-cultured CTLs. Interestingly, additional extracellular Ca2+ diminished HG-enhanced CTL killing function. Our findings suggest that in an environment with excessive glucose, CTLs could eliminate target cells more efficiently, at least for a certain period of time, in a Ca2+-dependent manner.