Immune modulation in cancer with antibodies

Elucidation of Spatial Cooperativity in Chemo-Immunotherapy by a Sequential Dual-pH-Responsive Drug Delivery System

Combining immune checkpoint blockade with chemotherapy through nanotechnology is promising in terms of safety and efficacy. However, the distinct subcellular distribution of each ingredient's action site makes it challenging to acquire an optimal synergism. Herein, a dual-pH responsive hybrid polymeric micelle system, HNP(αPDL16.9, Dox5.3), is constructed as a proof-of-concept for the spatial cooperativity in chemo-immunotherapy. HNP retains the inherent pH-transition of each polymer, with stepwise disassembly under discrete pH thresholds. Within weakly acidic extracellular tumor environment, αPDL1 is first released to block the checkpoint on cell membranes. The remaining intact Doxorubicin-loaded micelle NP(Dox)5.3 displays significant tropism toward tumor cells and releases Dox upon lysosomal pH for efficient tumor immunogenic cell death without immune toxicity. This sequential-released pattern boosts DC activation and primes CD8+ T cells, leading to enhanced therapeutic performance than single agent or an inverse-ordered combination in multiple murine tumor models. Using HNP, the indispensable role of conventional type 1 DC (cDC1) is identified in chemo-immunotherapy. A co-signature of cDC1 and CD8 correlates with cancer patient survival after neoadjuvant Pembrolizumab plus chemotherapy in clinic. This study highlights spatial cooperativity of chemo- and immuno-agents in immunoregulation and provides insights into the rational design of drug combination for future nanotherapeutics development.

Engineering Antigen-Specific Tolerance to an Artificial Protein Hydrogel

Artificial protein hydrogels are an emerging class of biomaterials with numerous prospective applications in tissue engineering and regenerative medicine. These materials are likely to be immunogenic due to their frequent incorporation of novel amino acid sequence domains, which often serve a functional role within the material itself. We engineered injectable "self" and "nonself" artificial protein hydrogels, which were predicted to have divergent immune outcomes in vivo on the basis of their primary amino acid sequence. Following implantation in mouse, the nonself gels raised significantly higher antigel antibody titers than the corresponding self gels. Prophylactic administration of a fusion antibody targeting the nonself hydrogel epitopes to DEC-205, an endocytic receptor involved in Treg induction, fully suppressed the elevated antibody titer against the nonself gels. These results suggest that the clinical immune response to artificial protein biomaterials, including those that contain highly antigenic sequence domains, can be tuned through the induction of antigen-specific tolerance.

Current strategies for targeting HPK1 in cancer and the barriers to preclinical progress

INTRODUCTION

Hematopoietic progenitor kinase 1 (HPK1), a 97-kDa serine/threonine Ste20-related protein kinase, functions as an intracellular negative regulator, primarily in hematopoietic lineage cells, where it regulates T cells, B cells, dendritic cells, and other immune cells. Loss of HPK1 kinase activity results in exacerbated cytokine secretion, enhanced T cell signaling, improved viral clearance, and thus increased restraint of tumor growth. These findings highlight HPK1 as a promising target for immuno-oncology treatments, culminating in the advancement of candidate compounds targeting HPK1 to clinical trials by several biotech enterprises.

AREAS COVERED

Through searching PubMed, Espacenet-patent search, and clinicaltrials.gov, this review provides a comprehensive analysis of HPK1, encompassing its structure and roles in various downstream signaling pathways, the consequences of constitutive activation of HPK1, and potential therapeutic strategies to treat HPK1-driven malignancies. Moreover, the review outlines the patents issued for small molecule inhibitors and clinical investigations of HPK1.

EXPERT OPINION

To enhance the success of tumor immunotherapy in clinical trials, it is important to develop protein degraders, allosteric inhibitors, and antibody-drug conjugates based on the crystal structure of HPK1, and to explore combination therapy approaches. Although several challenges remain, the development of HPK1 inhibitors display promising in preclinical and clinical studies.

Deletion of MyD88 in T Cells Improves Antitumor Activity in Melanoma

Cytotoxic CD8+ T cells are central to the antitumor immune response by releasing cytotoxic granules that kill tumor cells. They are activated by antigen-presenting cells, which become activated by DAMPs (damage associated molecular patterns) through MyD88. However, the suppressive tumor microenvironment promotes T-cell tolerance to tumor antigens in part by enhancing the activity of immune checkpoint molecules that prevent CD8+ T-cell activation and cytotoxicity. The authors recently reported that MyD88 limits CD4+ T-cell activation during cardiac adaptation to stress and hypothesized that a similar mechanism exists in CD8+ T cells that could be modulated to improve antitumor immunity. The authors found that adoptive transfer of MyD88-/- CD8+ T cells in melanoma-bearing T-cell-deficient mice resulted in slower tumor growth, greater intratumoral T-cell accumulation, and higher melanoma cell death compared with transfer of wild-type CD8+ T cells. These findings were also observed in T-cell-specific MyD88-/- mice compared with wild-type littermates implanted with melanoma. Mechanistically, deletion of MyD88 enhances CD8+ T-cell activation and survival, and T-cell receptor induced degranulation of cytotoxic molecules, overall improving their killing of melanoma cells. This enhanced cytotoxicity was retained in mice bearing tumors expressing the specific antigen for which cytotoxic T-cells were restricted. This study's results demonstrate a conserved mechanism for MyD88 in modulating CD8+ T-cell activation and represent a novel target in improving cancer immunotherapy.

Depletion of PHLDB2 Suppresses Epithelial-Mesenchymal Transition and Enhances Anti-Tumor Immunity in Head and Neck Squamous Cell Carcinoma

The role of Pleckstrin homology-like domain family B member 2 (PHLDB2) in the regulation of cell migration has been extensively studied. However, the exploration of PHLDB2 in head and neck squamous cell carcinoma (HNSCC) is still limited in terms of expression, function, and therapeutic potential. In this study, we discovered an upregulation of PHLDB2 expression in HNSCC tissues which was correlated with a negative prognosis in patients with HNSCC. Additionally, we determined that a high level of expression of PHLDB2 is crucial for maintaining cell migration through the regulation of the epithelial-mesenchymal transition (EMT). Furthermore, we demonstrated that the ablation of PHLDB2 in tumor cells inhibited tumorigenicity in a C3H syngeneic tumor-bearing mouse model. Mechanistically, PHLDB2 was found to be involved in the regulation of T cell anti-tumor immunity, primarily by enhancing the activation and infiltration of CD8+ T cells. In light of these findings, PHLDB2 emerges as a promising biomarker and therapeutic target for interventions in HNSCC.

Balancing the Nanoscale Organization in Multivalent Materials for Functional Inhibition of the Programmed Death-1 Immune Checkpoint

Dendritic cells (DCs) regulate immune priming by expressing programmed death ligand 1 (PD-L1) and PD-L2, which interact with the inhibitory receptor PD-1 on activated T cells. PD-1 signaling regulates T cell effector functions and limits autoimmunity. Tumor cells can hijack this pathway by overexpressing PD-L1 to suppress antitumor T cell responses. Blocking this inhibitory pathway has been beneficial for the treatment of various cancer types, although only a subset of patients responds. A deepened understanding of the spatial organization and molecular interplay between PD-1 and its ligands may inform the design of more efficacious nanotherapeutics. We visualized the natural molecular PD-L1 organization on DCs by DNA-PAINT microscopy and created a template to engineer DNA-based nanoclusters presenting PD-1 at defined valencies, distances, and patterns. These multivalent nanomaterials were examined for their cellular binding and blocking ability. Our data show that PD-1 nano-organization has profound effects on ligand interaction and that the valency of PD-1 molecules modulates the effectiveness in restoring T cell function. This work highlights the power of spatially controlled functional materials to unravel the importance of multivalent patterns in the PD-1 pathway and presents alternative design strategies for immune-engineering.

Extracellular vesicle-mediated ferroptosis, pyroptosis, and necroptosis: potential clinical applications in cancer therapy

Extracellular vesicles (EVs) have gained increasing recognition as significant regulators of intercellular communication in various physiological and pathological processes. These vesicles play a pivotal role in cancer progression by facilitating the transfer of diverse cargoes, including lipids, proteins, and nucleic acids. Regulated cell death (RCD), the orderly and autonomous death of cells, is controlled by a variety of biomacromolecules and, in turn, influences various biological processes and cancer progression. Recent studies have demonstrated that EV cargoes regulate diverse oncogenes and tumor suppressors to mediate different nonapoptotic forms of RCD, notably ferroptosis, pyroptosis, and necroptosis. Nevertheless, comprehensive exploration of EV-mediated nonapoptotic RCD forms in the context of cancer has not been performed. This review summarizes the progress regarding the biological functions and underlying mechanisms of EVs in mediating nonapoptotic RCD by delivery of cargoes to regulate tumor progression. Additionally, the review delves into the potential clinical applications of EV-mediated cell death and its significance in the areas of cancer diagnosis and therapy.

Thyroid dysfunction induced by anti-PD-1 therapy is associated with a better progression-free survival in patients with advanced carcinoma

PURPOSE

Thyroid dysfunction is the most common immune-related adverse event during anti-programmed cell death 1 (anti-PD-1) therapy. In this study, we monitored patients with advanced malignant tumors who received anti-PD-1 therapy to observe the characteristic of anti-PD-1 therapy-induced thyroid dysfunction and its correlation with prognosis.

METHODS

Patients with advanced carcinoma treated with anti-PD-1 therapy were evaluated for thyroid function at baseline and after treatment initiation from August 2020 to March 2022. Seventy-three patients were finally included in the study.

RESULTS

Among these patients, 19 (26.03%) developed thyroid dysfunction after receiving anti-PD-1 therapy. Primary hypothyroidism and thyrotoxicosis were the most common clinical manifestation. Anti-PD-1-induced thyroid dysfunction occurred 63 (26-131) days after administration; thyrotoxicosis appeared earlier than primary hypothyroidism. In Kaplan-Meier survival analysis, the progression-free survival (PFS) of the thyroid dysfunction group was better than that of the no thyroid dysfunction group (227 (95% confidence interval (CI) 50.85-403.15) days vs 164 (95% CI 77.76-250.24) days, p = 0.026). Male patients had better PFS than female patients (213 (95% CI 157.74-268.26) days vs 74 (95% CI 41.23-106.77) days, p = 0.031). In cox proportional hazards regression model, anti-PD-1-induced thyroid dysfunction remained an independent predictor of better PFS (hazard ratio (HR) = 0.339(0.136-0.848), p = 0.021).

CONCLUSION

Thyroid dysfunction is a common immune-related adverse events in advanced cancer patients treated with anti-PD-1 therapy and predicts a better prognosis.

TRIAL REGISTRATION

This study was retrospectively registered with Trial ClinicalTrials.gov (NCT05593744) on October 25, 2022.

Targeting MS4A4A on tumour-associated macrophages restores CD8+ T-cell-mediated antitumour immunity

OBJECTIVE

Checkpoint immunotherapy unleashes T-cell control of tumours but is suppressed by immunosuppressive myeloid cells. The transmembrane protein MS4A4A is selectively highly expressed in tumour-associated macrophages (TAMs). Here, we aimed to reveal the role of MS4A4A+ TAMs in regulating the immune escape of tumour cells and to develop novel therapeutic strategies targeting TAMs to enhance the efficacy of immune checkpoint inhibitor (ICI) in colorectal cancer.

DESIGN

The inhibitory effect of MS4A4A blockade alone or combined with ICI treatment on tumour growth was assessed using murine subcutaneous tumour or orthotopic transplanted models. The effect of MS4A4A blockade on the tumour immune microenvironment was assessed by flow cytometry and mass cytometry. RNA sequencing and western blot analysis were used to further explore the molecular mechanism by which MS4A4A promoted macrophages M2 polarisation.

RESULTS

MS4A4A is selectively expressed by TAMs in different types of tumours, and was associated with adverse clinical outcome in patients with cancer. In vivo inhibition of MS4A4A and anti-MS4A4A monoclonal antibody treatment both curb tumour growth and improve the effect of ICI therapy. MS4A4A blockade treatment reshaped the tumour immune microenvironment, resulting in reducing the infiltration of M2-TAMs and exhausted T cells, and increasing the infiltration of effector CD8+ T cells. Anti-MS4A4A plus anti-programmed cell death protein 1 (PD-1) therapy remained effective in large, treatment-resistant tumours and could induce complete regression when further combined with radiotherapy. Mechanistically, MS4A4A promoted M2 polarisation of macrophages by activating PI3K/AKT pathway and JAK/STAT6 pathway.

CONCLUSION

Targeting MS4A4A could enhance the ICI efficacy and represent a new anticancer immunotherapy.

Bioinspired immuno-radio-enhancers toward synergistic nanomedicine through radiation-induced abscopal effects and immunocheckpoint blockade therapies

Local radio-therapy combined with immunotherapy has attracted great interest in controlling local tumors. In this study, we have developed membrane-cloaked manganese dioxide nanoparticles displaying anti-PD-L1 antibodies as targeted immuno-radio-enhancers. Mediated by anti-PD-L1 antibodies (aPD-L1) expressed on cell membranes, this kind of membrane-coated nanosystem can selectively deliver cytosine-phosphate-guanine (CpG)-loaded MnO2 nanoparticles (NPs) and induce systemic anti-tumor immunities, thereby achieving favorable immuno/radio-therapeutic outcomes. Through expressing various functional proteins onto cellular membranes, the new class of membrane-camouflaged nanovehicles can be endowed with a wide variety of artificial functionalities such as enzymatic catalytic capabilities and specific targeting. This versatile nanoplatform, in general, enables the targeted delivery of theranostics, opening a new avenue for personalized nanomedicine.

Multimodal Management With Immunotherapy, Radiation, and Surgery of Histiocytic Sarcoma Following Acute Lymphoblastic Leukemia: An Unusual Presentation of a Rare Disease

Histiocytic sarcoma (HS) is a rare neoplasm with no known cause. This sarcoma is characterized by morphology similar to that demonstrated by mature tissue histiocytes and mostly afflicts adults. HSs typically have a poor prognosis due to a rapidly progressive clinical course. Our patient's case was unique due to its presentation four years after completion of treatment for B-cell acute lymphoblastic leukemia. The patient experienced progression with initial therapy for HS. With dual immunotherapy and radiation, however, the patient has remained clinically stable without detectable disease. Immunotherapy may be a successful and tolerable therapeutic option for histiocytic disease.

PD-1 receptor outside the main paradigm: tumour-intrinsic role and clinical implications for checkpoint blockade

Blocking the inhibitory receptor PD-1 on antitumour T lymphocytes is the main rationale underlying the clinical successes of cancer immunotherapies with checkpoint inhibitor (CI) antibodies (Abs). Besides this main paradigm, there is recent evidence of unconventional and "ectopic" signalling pathways of PD-1, found to be expressed not only by lymphocytes but also by peculiar subsets of cancer cells. Several groups reported on the tumour-intrinsic role of PD-1 in multiple settings, including melanoma, hepatocellular, thyroid, lung, pancreatic and colorectal cancer. Its functional activity appears intriguing but is not yet conclusively clarified. The initial studies are, in fact, supporting either a pro-tumourigenic role involved in chemoresistance and disease relapse or, oppositely, tumour-suppressive functions. The implications connected to the therapeutic administration of PD-1 blocking Abs are, of course, potentially relevant, respectively inferring an anti-tumour activity contrasting PD-1+ tumourigenic cells or a pro-tumoural effect by tackling PD-1 tumour suppressive signalling. The progressive exploration and consideration of this new paradigm of tumour-intrinsic PD-1 signalling may improve the interpretation of the observed clinical effects by anti-PD-1 Abs, likely resulting from multiple cumulative activities, and might provide important bases for dedicated clinical studies that take into account such composite roles of PD-1.

Encapsulation of STING Agonist cGAMP with Folic Acid-Conjugated Liposomes Significantly Enhances Antitumor Pharmacodynamic Effect

Background: 2',3'-cGAMP (2',3'-cyclic AMP-GMP) has been reported as an agonist of the STING (stimulator of interferon genes) signaling pathway. However, cGAMP has poor membrane permeability and can be hydrolyzed by ectonucleotide pyrophosphatase/phosphodiesterase (ENPP1), limiting its ability to activate the STING-IRF3 pathway. This study aimed to investigate that the folate-targeted liposomal cGAMP could overcome the defects of free cGAMP to enhance the antitumor effect. Materials and Methods: cGAMP was encapsulated in PEGylated folic acid-targeted liposomes to construct a carrier-delivered formulation. The particle size and morphology were detected by dynamic light scattering and transmission electron microscopy. The sustained-release ability was measured by drug release and pharmacokinetics. Animal models were applied to evaluate the tumor inhibition efficiency in vivo. Flow cytometry, enzyme-linked immunosorbent assay, and real-time polymerase chain reaction were used to detect the expression of immune cells, secreted cytokines, and target genes. The activation of the STING-IRF3 pathway was evaluated by immunofluorescence. Results: Physical characters of liposomes revealed that the prepared liposomes were stable in neutral humoral environments and released more internal drugs in acidic tumor tissues. Systemic therapy with liposomes on Colorectal 26 tumor-bearing mice in vivo effectively inhibited tumor growth via stimulating the expression of CD8+ T cells and reversed the immunosuppressed tumor microenvironment (TME). Conclusions: The study suggests that the folic acid-targeted cGAMP-loaded liposomes deliver drugs to the TME to enhance the STING agonist activity, improving the efficiency of tumor therapy via the cGAMP-STING-IRF3 pathway.

A novel bivalent anti-c-MET/PD-1 bispecific antibody exhibits potent cytotoxicity against c-MET/PD-L1-positive colorectal cancer

Previously, we generated a novel bispecific antibody (BsAb) simultaneously targeting both c-MET and PD-1 (PDCD1), which can bridge T cells and c-MET positive tumor cells. However, the specific mechanisms and antitumor activities of the BsAb against c-MET/PD-L1 (CD274) positive colorectal cancer (CRC) is not completely understood. In this study, in addition to the tumor intrinsic mechanism investigation with molecular biology assay in vitro, a humanized mouse model was used to evaluate antitumor activity of the BsAb in vivo. The BsAb could inhibit c-MET/PD-L1+ CRC cell migration and show strong antitumor activity against HCT116 tumors in mice, potentially by inducing the degradation of c-MET protein in a dose and time-dependent manner. The BsAb could suppress the phosphorylation of c-MET downstream proteins GRB2-associated-binding protein 1 (Gab1) and focal adhesion kinase (FAK). Considering the tumor extrinsic mechanism, the BsAb may promote phagocytosis of macrophage. Furthermore, the level of plasma exosomal-c-MET/PD-L1 is able to distinguish CRC patients from healthy controls. In summary, the BsAb exhibited potent anti-tumor activities by two distinguished mechanisms: inhibition of c-MET signal transduction and promotion of macrophage-mediated phagocytosis. Our BsAb may provide a novel therapeutic agent for patients with c-MET/PD-L1+ CRC, and the status of exosomal-c-MET/PD-L1 can serve as a biomarker to predict responsiveness to treatment of our BsAb.

USP2 promotes tumor immune evasion via deubiquitination and stabilization of PD-L1

The abnormal upregulation of programmed death ligand-1 (PD-L1) on tumor cells impedes T-cell mediated cytotoxicity through PD-1 engagement, and further exploring the mechanisms regulation of PD-L1 in cancers may enhance the clinical efficacy of PD-L1 blockade. Here, using single-guide RNAs (sgRNAs) screening system, we identify ubiquitin-specific processing protease 2 (USP2) as a novel regulator of PD-L1 stabilization for tumor immune evasion. USP2 directly interacts with and increases PD-L1 abundance in colorectal and prostate cancer cells. Our results show that Thr288, Arg292 and Asp293 at USP2 control its binding to PD-L1 through deconjugating the K48-linked polyubiquitination at lysine 270 of PD-L1. Depletion of USP2 causes endoplasmic reticulum (ER)-associated degradation of PD-L1, thus attenuates PD-L1/PD-1 interaction and sensitizes cancer cells to T cell-mediated killing. Meanwhile, USP2 ablation-induced PD-L1 clearance enhances antitumor immunity in mice via increasing CD8+ T cells infiltration and reducing immunosuppressive infiltration of myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs), whereas PD-L1 overexpression reverses the tumor growth suppression by USP2 silencing. USP2-depletion combination with anti-PD-1 also exhibits a synergistic anti-tumor effect. Furthermore, analysis of clinical tissue samples indicates that USP2 is positively associated with PD-L1 expression in cancer. Collectively, our data reveal a crucial role of USP2 for controlling PD-L1 stabilization in tumor cells, and highlight USP2 as a potential therapeutic target for cancer immunotherapy.

Exosomes in the Diagnosis and Treatment of Renal Cell Cancer

Renal cell carcinoma (RCC) is the most prevalent type of kidney cancer originating from renal tubular epithelial cells, with clear cell RCC comprising approximately 80% of cases. The primary treatment modalities for RCC are surgery and targeted therapy, albeit with suboptimal efficacies. Despite progress in RCC research, significant challenges persist, including advanced distant metastasis, delayed diagnosis, and drug resistance. Growing evidence suggests that extracellular vesicles (EVs) play a pivotal role in multiple aspects of RCC, including tumorigenesis, metastasis, immune evasion, and drug response. These membrane-bound vesicles are released into the extracellular environment by nearly all cell types and are capable of transferring various bioactive molecules, including RNA, DNA, proteins, and lipids, aiding intercellular communication. The molecular cargo carried by EVs renders them an attractive resource for biomarker identification, while their multifarious role in the RCC offers opportunities for diagnosis and targeted interventions, including EV-based therapies. As the most versatile type of EVs, exosomes have attracted much attention as nanocarriers of biologicals, with multi-range signaling effects. Despite the growing interest in exosomes, there is currently no widely accepted consensus on their subtypes and properties. The emerging heterogeneity of exosomes presents both methodological challenges and exciting opportunities for diagnostic and clinical interventions. This article reviews the characteristics and functions of exosomes, with a particular reference to the recent advances in their application to the diagnosis and treatment of RCC.

The role of tumor immune microenvironment in chordoma: promising immunotherapy strategies

Chordoma is a rare malignant bone tumor with limited therapeutic options, which is resistant to conventional chemotherapy and radiotherapy, and targeted therapy is also shown with little efficacy. The long-standing delay in researching its mechanisms of occurrence and development has resulted in the dilemma of no effective treatment targets and no available drugs in clinical practice. In recent years, the role of the tumor immune microenvironment in driving tumor growth has become a hot and challenging topic in the field of cancer research. Immunotherapy has shown promising results in the treatment of various tumors. However, the study of the immune microenvironment of chordoma is still in its infancy. In this review, we aim to present a comprehensive reveal of previous exploration on the chordoma immune microenvironment and propose promising immunotherapy strategies for chordoma based on these characteristics.

Jianpi Yangzheng Xiaozheng decoction alleviates gastric cancer progression via suppressing exosomal PD-L1

Jianpi Yangzheng Xiaozheng decoction (JPYZXZ) is an empirical traditional Chinese medicine formula that has been reported to significantly prolong the survival of patients with advanced gastric cancer (GC). However, its underlying mechanism have not been fully elucidated. The present work aims to explore the possible mechanism of JPYZXZ on regulating GC progression. We firstly confirmed the inhibitory effect of JPYZXZ in GC MKN74 cells and 615-strain mice, which was possibly mediated with IL-6/JAK2/STAT3 pathway dependent PD-L1 expression. Moreover, we showed that JPYZXZ diminished the expression levels of GC-derived exosomal PD-L1 in MFC murine cells and xenograft GC model, as well as stage IIA-IIIB GC patients. We further found that in different types of tumor-infiltrating immune cells, PD-L1 expression was most positively correlated with myeloid-derived suppressor cells (MDSCs) in GC in the TISIDB database. We isolated exosomes derived from supernatants of MFC cells and co-cultured with bone marrow cells derived from C57BL/6 mice, and further revealed that the expansion of MDSCs was mediated by GC-derived exosomal PD-L1. Meanwhile, our results indicated that JPYZXZ inhibited the delivery of exosomal PD-L1 from GC cells to bone marrow cells, thereby alleviating exosomal PD-L1-induced differentiation and expansion of MDSCs in the tumor microenvironment. This led to a decrease in the levels of several immunosuppressive factors, including iNOS, Arg-1, TGF-β, IL-10, and IL-6, in 615-strain mice. Moreover, clinical data also revealed a significant positive relationship between exosomal PD-L1 and polymorphonuclear MDSCs under the JPYZXZ treatment in stage IIA-IIIB GC patients. In conclusion, our study confirmed that exosomal PD-L1 could be a key factor in controlling MDSCs differentiation in GC. JPYZXZ alleviated GC progression via suppressing exosomal PD-L1 mediated expansion of MDSCs, thereby remodeling the immunosuppressive tumor microenvironment, which provided the experimental evidence for the clinical application of JPYZXZ in the treatment of GC via PD-L1.

Immune dysregulation and potential targeted therapy in myelodysplastic syndrome

Myelodysplastic syndrome (MDS) is a heterogeneous group of clonal hematological diseases and a high risk for transformation to acute myeloid leukemia (AML). The identification of key genetic alterations in MDS has enhanced our understanding of the pathogenesis and evolution. In recent years, it has been found that both innate and adaptive immune signaling are activated in the hematopoietic niche of MDS with aberrant cytokine secretion in the bone marrow microenvironment. It is also clear that immune dysregulation plays an important role in the occurrence and progression of MDS, especially the destruction of the bone marrow microenvironment, including hematopoiesis and stromal components. The purpose of this review is to explore the role of immune cells, the immune microenvironment, and cytokines in the pathogenesis of MDS. Insights into the mechanisms of these variants may facilitate the development of novel effective treatments to prevent disease progression.

Friend or Foe - Tc17 cell generation and current evidence for their importance in human disease

The term Tc17 cells refers to interleukin 17 (IL-17)-producing CD8+ T cells. While IL-17 is an important mediator of mucosal defense, it is also centrally involved in driving the inflammatory response in immune-mediated diseases, such as psoriasis, multiple sclerosis, and inflammatory bowel disease. In this review, we aim to gather the current knowledge on the phenotypic and transcriptional profile, the in vitro and in vivo generation of Tc17 cells, and the evidence pointing towards a relevant role of Tc17 cells in human diseases such as infectious diseases, cancer, and immune-mediated diseases.

Immune-related adverse events associated with nab-paclitaxel/paclitaxel combined with immune checkpoint inhibitors: a systematic review and network meta-analysis

Objective

The combination of nanoparticle albumin-bound paclitaxel (nab-PTX)/paclitaxel (PTX) with immune checkpoint inhibitors (ICIs) has demonstrated significant efficacy in cancer patients. However, the safety of these combination regimens remains conflicting in former researches. Therefore, in order to address this issue, we performed a systematic review and network meta-analysis (NMA) to evaluate and compare the safety profile.

Methods

We performed a systematic review by searching randomized controlled trials (RCTs) from PubMed, EMBASE, Cochrane Library, ClinicalTrials.gov, and Web of Science up to August 15, 2022. The primary outcomes were all-grade (grade 1-5) and high-grade (grade 3-5) immune-related adverse events (irAEs). Secondary outcomes were all-grade (grade 1-5) and high-grade (grade 3-5) irAEs of subgroups of ICIs.

Results

There were 22 RCTs included in the NMA, involving a total of 15 963 patients diagnosed with any type of cancer. ICIs+nab-PTX was associated with a noticeably decreased risk of grade 3-5 pneumonitis (odds ratio [OR]=0.28, 95% credible interval [CrI]: 0.09,0.90) compared to ICI monotherapy; ICIs+PTX showed a lower risk of grade 1-5 hyperthyroidism (OR=0.46, 95% CrI: 0.22-0.96) and grade 1-5 hypothyroidism (OR=0.49, 95% CrI: 0.26-0.93) than ICIs. Compared with PD-1, PD-1+PTX was associated with a statistically significantly lower risk of grade 1-5 pneumonitis (OR=0.32, 95% CrI: 0.11-0.92). PD-L1 resulted in a noticeably lower risk of grade 1-5 hypothyroidism (OR=0.34, 95% CrI: 0.12-1.00) than PD-L1+PTX. Nearly all treatment regimens containing ICIs demonstrated significantly higher risks of irAEs compared to the standard chemotherapy groups.

Conclusion

Nab-PTX/PTX+ICIs demonstrated an approach leading to decreased risk of irAEs compared with ICI monotherapy. This finding supports that ICIs+nab-PTX/PTX may be a safer treatment strategy. Moreover, we also found that the combination regimens containing ICIs had a higher risk of irAEs than standard chemotherapy. Additionally, ICIs+nab-PTX demonstrated a decreased risk of irAEs compared to ICIs+PTX. PD-1 inhibitors were associated with a higher risk of irAEs than PD-L1 inhibitors.

Soluble CD80 oral delivery by recombinant Lactococcus suppresses tumor growth by enhancing antitumor immunity

CD80 is an important co-stimulatory molecule that participates in the immune response. Soluble CD80 can induce T cell activation and overcome PDL1-mediated immune suppression. In this study, we aimed to construct recombinant Lactococcus lactis for oral delivery of the soluble CD80 (hsCD80) protein or the fusion protein containing the cholera toxin B subunit (CTB) and hsCD80 (CTB-hsCD80) under the control of the nisin-inducible expression system. The recombinant L. lactis expressed and secreted hsCD80 or CTB-hsCD80 fusion proteins after induction by nisin in vitro and in the enteric cavity. Additionally, the CTB-hsCD80 fusion protein showed uptake by intestinal epithelial cells, was cleaved by the furin protease, and was released as free hsCD80 protein into the blood circulation. Orally administered hsCD80 and CTB-hsCD80 containing L. lactis increased the proportion of activated T cells in the spleen and intestinal epithelium, inhibited tumor growth, and prolonged the survival of tumor-bearing mice. The hsCD80-containing L. lactis showed greater therapeutic effects on primary colonic adenoma in APC^min/- mice and completely suppressed tumor growth. Further, recombinant CTB-hsCD80 in L. lactis was more efficient than hsCD80-containing bacteria in inhibiting the growth of xenografted colon cancer and melanoma cells. hsCD80 engineered probiotics may serve as a promising new approach for antitumor immunotherapy, especially for colorectal cancer.

Advancements in pH-responsive nanocarriers: enhancing drug delivery for tumor therapy

INTRODUCTION

Tumors pose a significant global economic and health burden, with conventional cancer treatments lacking tumor specificity, leading to limited efficiency and undesirable side effects. Targeted tumor therapy is imminent. Tumor cells produce lactate and hydrogen ions (H+) by Warburg effect, forming an acidic tumor microenvironment (TME), which can be employed to design targeted tumor therapy. Recently, progress in nanotechnology has led to the development of pH-responsive nanocarriers, which have gathered significant attention. Under acidic tumor conditions, they exhibit targeted accumulation within tumor sites and controlled release profiles of therapeutic reagents, enabling precise tumor therapy.

AREAS COVERED

This review comprehensively summarize the principles underlying pH-responsive features, discussing various types of pH-responsive nanocarriers, their advantages, and limitations. Innovative therapeutic drugs are also examined, followed by an exploration of recent advancements in applying various pH-responsive nanocarriers as delivery systems for enhanced tumor therapy.

EXPERT OPINIONS

pH-responsive nanocarriers have garnered significant attention for their capability to achieve targeted accumulation of therapeutic agents at tumor sites and controlled drug delivery profiles, ultimately increasing the efficiency of tumor eradication. It is anticipated that the employment of pH-responsive nanocarriers will elevate the effectiveness and safety of tumor therapy, contributing to improved overall outcomes.

Management of Cutaneous Head and Neck Squamous and Basal Cell Carcinomas for Immunocompromised Patients

The incidence of non-melanoma skin cancer (NMSC) continues to rise, and more than one million cases are diagnosed in the United States each year. The increase in prevalence has been attributed to increased lifespan and improvements in survival for conditions that increase the risk of these malignancies. Patients who are immunocompromised have a higher risk of developing NMSC compared to the general population. In immunosuppressed patients, a combination of prevention, frequent surveillance, and early intervention are necessary to reduce morbidity and mortality. In this review, we collate and summarize current knowledge regarding pathogenesis of head and neck cutaneous SCC and BCC within immunocompromised patients, examine the potential role of the immune response in disease progression, and detail the role of novel immunotherapies in this subset of patients.

Application of CRISPR screen in mechanistic studies of tumor development, tumor drug resistance, and tumor immunotherapy

Tumor is one of the biggest threats to human health. Though tumor therapy has been dramatically advanced by the progress of technology and research in recent decades, it is still far from expectations. Thus, it is of great significance to explore the mechanisms of tumor growth, metastasis, and resistance. Screen based on Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-CRISPR-associated protein (Cas) 9 gene editing technology are powerful tools for exploring the abovementioned facets. This review summarizes the recent screen performed in cancer cells and immune cells in the tumor microenvironment. The screens in cancer cells mainly focus on exploring the mechanisms underlying cancer cells' growth, metastasis, and how cancer cells escape from the FDA approved drugs or immunotherapy. And the studies in tumor-associated immune cells are primarily aimed at identifying signaling pathways that can enhance the anti-tumor function of cytotoxic T lymphocytes (CTLs), CAR-T cells, and macrophages. Moreover, we discuss the limitations, merits of the CRISPR screen, and further its future application in tumor studies. Importantly, recent advances in high throughput tumor related CRISPR screen have deeply contributed to new concepts and mechanisms underlying tumor development, tumor drug resistance, and tumor immune therapy, all of which will eventually potentiate the clinical therapy for tumor patients.

Analysis of the characteristics of immune infiltration in endometrial carcinoma and its relationship with prognosis based on bioinformatics

To explore immune-related molecules that affect the prognosis of endometrial carcinoma (EC) using bioinformatic data mining. The expression data related to EC were downloaded from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus databases. After differential expression analysis, the intersection with immune related genes in the ImmPort database was used to obtain immune related differentially expressed genes (IRDEGs). The correlation between clinicopathological information and the prognosis of IRDEGs was further analyzed to obtain prognosis related differentially expressed immune genes (PRDEIG). Gene correlation analysis and Gene Set Enrichment Analysis (GSEA) enrichment analysis showed that PRDEIG was enriched in cancer-related functional pathways. We then analyzed the relationship between PRDEIG and immune cell infiltration, and further analyzed the mRNA and protein expression of PRDEIG in EC using TCGA and the human protein expression atlas (THPA) databases. After the intersection of the differential expression analysis results and immune-related genes, 4 IRDEGs were obtained: osteoglycin (OGN), LTBP4, CXCL12, and SPP1. After analyzing the relationship between 4 IRDEGs and clinicopathological parameters and prognosis of patients with EC, revealed that only OGN was not only related to tumor immunity, but also affected the prognosis of patients with EC. Gene correlation and GSEA enrichment of OGN were analyzed. The results showed that OGN was significantly enriched in 6 functional pathways: epithelial mesenchymal transition, KRAS signaling up, myogenesis, UV response, allograft rejection and apical junction. In addition, it was also found that OGN was significantly correlated with a variety of immune cells. The results of TCGA and THPA database showed that the mRNA and protein expression levels of OGN decreased in EC. OGN may affect the epithelial mesenchymal transformation (EMT) of tumor by affecting the infiltration of tumor immune cells.

Targeted co-delivery of PD-L1 monoclonal antibody and sorafenib to circulating tumor cells via platelet-functionalized nanocarriers

BACKGROUND

Circulating tumor cells (CTCs) can adsorb and activate platelets to form a microthrombus protective barrier around them, so that therapeutic drugs and immune cells cannot effectively kill CTCs. The platelet membrane (PM) bionic carrying drug system has the powerful ability of immune escape, and can circulate in the blood for a long time.

MATERIALS AND METHODS

we developed platelet membrane coated nanoparticles (PM HMSNs) to improve the precise delivery of drugs to tumor sites and to achieve more effective immunotherapy combined with chemotherapy strategy.

RESULTS

Successfully prepared aPD-L1-PM-SO@HMSNs particles, whose diameter is 95-130 nm and presenting the same surface protein as PM. Laser confocal microscopy and flow cytometry experimental results showed that the fluorescence intensity of aPD-L1-PM-SO@HMSNs was greater than SO@HMSNs that are not coated by PM. Biodistribution studies in H22 tumor-bearing mice showed that due to the combined action of the active targeting effect and the EPR effect, the high accumulation of aPD-L1-PM-SO@HMSNs in the local tumor was more effective in inhibiting tumor growth than other groups of therapeutic agents.

CONCLUSION

Platelet membrane biomimetic nanoparticles have a good targeted therapeutic effect, which can effectively avoid immune clearance and have little side effects. It provides a new direction and theoretical basis for further research on targeted therapy of CTCs in liver cancer.

Regulations of Tumor Microenvironment by Prostaglandins

Prostaglandins, the bioactive lipids generated from the metabolism of arachidonic acid through cyclooxygenases, have potent effects on many constituents of tumor microenvironments. In this review, we will describe the formation and activities of prostaglandins in the context of the tumor microenvironment. We will discuss the regulation of cancer-associated fibroblasts and immune constituents by prostaglandins and their roles in immune escapes during tumor progression. The review concludes with future perspectives on improving the efficacy of immunotherapy through repurposing non-steroid anti-inflammatory drugs and other prostaglandin modulators.

CD39 (ENTPD1) in tumors: a potential therapeutic target and prognostic biomarker

As a regulator of the dynamic balance between immune-activated extracellular ATP and immunosuppressive adenosine, CD39 ectonucleotidase impairs the ability of immune cells to exert anticancer immunity and plays an important role in the immune escape of tumor cells within the tumor microenvironment. In addition, CD39 has been studied in cancer patients to evaluate the prognosis, the efficacy of immunotherapy (e.g., PD-1 blockade) and the prediction of recurrence. This article reviews the importance of CD39 in tumor immunology, summarizes the preclinical evidence on targeting CD39 to treat tumors and focuses on the potential of CD39 as a biomarker to evaluate the prognosis and the response to immune checkpoint inhibitors in tumors.

PD-1/PD-L1 axis in organ fibrosis

Fibrosis is a pathological tissue repair activity in which many myofibroblasts are activated and extracellular matrix are excessively accumulated, leading to the formation of permanent scars and finally organ failure. A variety of organs, including the lung, liver, kidney, heart, and skin, can undergo fibrosis under the stimulation of various exogenous or endogenous pathogenic factors. At present, the pathogenesis of fibrosis is still not fully elucidated, but it is known that the immune system plays a key role in the initiation and progression of fibrosis. Immune checkpoint molecules are key regulators to maintain immune tolerance and homeostasis, among which the programmed cell death protein 1/programmed death ligand 1 (PD-1/PD-L1) axis has attracted much attention. The exciting achievements of tumor immunotherapy targeting PD-1/PD-L1 provide new insights into its use as a therapeutic target for other diseases. In recent years, the role of PD-1/PD-L1 axis in fibrosis has been preliminarily explored, further confirming the close relationship among PD-1/PD-L1 signaling, immune regulation, and fibrosis. This review discusses the structure, expression, function, and regulatory mechanism of PD-1 and PD-L1, and summarizes the research progress of PD-1/PD-L1 signaling in fibrotic diseases.

Efficacy of PD-1/PD-L1 inhibitors in advanced gastroesophageal cancer based on characteristics: a meta-analysis

Objective: Evaluate the potency of anti-PD-1/PD-L1 antibodies in advanced gastroesophageal cancer patients with different clinical features. Methods: Randomized, controlled trials comparing anti-PD-1/PD-L1 antibodies with chemotherapy in individuals with gastroesophageal cancer were retrieved. Results: 15 trials involving 9194 individuals were included. PD-1/PD-L1 inhibitors significantly improved overall survival (OS) but not progression-free survival. Significantly improved OS was observed in PD-L1 combined positive score ≥1, primary esophageal cancer, primary gastric cancer and Asian patients. Subgroup analysis revealed significant OS benefit achieved for esophageal squamous cell carcinoma, but not for esophageal adenocarcinoma. Conclusion: PD-1/PD-L1 inhibitors improved OS in advanced gastroesophageal carcinoma, especially in patients with esophageal cancer. Race, primary tumor sites and PD-L1 combined positive score can be used to predict the potency of immune checkpoint inhibitors.

Establishment of humanized mice and its application progress in cancer immunotherapy

The current high prevalence of malignant tumors has attracted considerable attention, and treating advanced malignancies is becoming increasingly difficult. Although immunotherapy is a hopeful alternative, it is effective in only a few people. Thus, development of preclinical animal models is needed. Humanized xenotransplantation mouse models can help with selecting treatment protocols, evaluating curative effects and assessing prognosis. This review discusses the establishment of humanized mouse models and their application prospects in cancer immunotherapy to identify tailored therapies for individual patients.

A Tumor Microenvironment-Driven Network Regulated by STAT3 and p65 Negatively Controls the Enrichment of Cancer Stem Cells in Human HR+/HER2- Breast Cancer

Hormone receptor-positive and HER2-negative (HR+/HER2-; luminal A) tumors are prevalent in breast cancer. Our past studies demonstrated that "TME Stimulation" (estrogen + TNFα + EGF, representing three arms of the tumor microenvironment, TME) has enriched metastasis-forming cancer stem cells (CSCs) in HR+/HER2- human breast cancer cells. Here, following information obtained by RNAseq analyses of TME-stimulated CSCs and Non-CSCs, we found that TME Stimulation has induced the activation of S727-STAT3, Y705-STAT3, STAT1 and p65. Upon TME Stimulation, stattic (STAT3 inhibitor) usage demonstrated that Y705-STAT3 activation negatively controlled CSC enrichment and epithelial-to-mesenchymal transition (EMT) traits, while inducing CXCL8 (IL-8) and PD-L1 expression. However, STAT3 knock-down (siSTAT3) had no effect on these functions; in terms of CSC enrichment, p65 had down-regulatory roles that compensated for the loss of an entire STAT3 protein. Y705-STAT3 and p65 acted additively in reducing CSC enrichment, and Y705A-STAT3 variant + sip65 has enriched chemo-resistant CSCs. Clinical data analyses revealed an inverse correlation between Y705-STAT3 + p65 phosphorylation and CSC signature in luminal A patients, and connection to improved disease course. Overall, we find regulatory roles for Y705-STAT3 and p65 in TME-stimulated HR+/HER2- tumors, with the ability to limit CSC enrichment. These findings raise concerns about using inhibitors of STAT3 and p65 as therapeutic strategies in the clinic.

Novel insights on the therapeutic effect of levamisole on the chronic toxoplasmosis in mice model

Latent toxoplasmosis mostly reactivates which could result in acute encephalitis. Chronic toxoplasmosis treatments are severely constrained by Toxoplasma cyst resistance. Novel therapeutic approaches are therefore becoming more essential. In this study, the effects of levamisole (LEVA) and spiramycin on the early and late stages of experimental toxoplasmosis are investigated.

MATERIALS AND METHODS

Seventy-five Me49 Toxoplasma gondii infected Swiss albino mice were divided into five groups; (GI): noninfected control group; (GII): infected untreated control group; (GIII): infected- LEVA treated group; (GIV): infected and received combination of spiramycin and LEVA and (GV): infected-spiramycin treated group. The impact was assessed through brain cyst count by Quantitative Real-Time Polymerase Chain Reaction (PCR), interferon gamma (IFN-γ) assay, histopathological study, and total blood counts.

RESULTS

The progression of chronic toxoplasmosis could only be partially controlled by using either levamisole or spiramycin as a separate drug. The combined spiramycin and levamisole treatment significantly decreased the burden of Toxoplasma brain cyst, increased IFN-γ level, total blood parameters and improved the histopathological features especially at the late stage of infection.

IN CONCLUSION

Levamisole effectively modulated Toxoplasma-induced immune responses, resulting in chronic toxoplasmosis remission. Further clinical trials will be needed to study the effect of these combination in HIV/AIDS (human immunodeficiency virus) patients with toxoplasmosis.

Pyroptosis-Mediated Synergistic Photodynamic and Photothermal Immunotherapy Enabled by a Tumor-Membrane-Targeted Photosensitive Dimer

Overcoming the resistance to apoptosis and immunosuppression of tumor cells is a significant challenge in augmenting the effect of cancer immunotherapy. Pyroptosis, a lytic programmed cell-death pathway unlike apoptosis, is considered a type of immunogenic cell death (ICD) that can intensify the ICD process in tumor cells, releasing dramatically increased tumor-associated antigens and damage-associated molecular patterns to promote cancer immunotherapy. Herein, a tumor cell membrane-targeted aggregation-induced emission photosensitive dimer is found to be able to achieve highly efficient ICD under the synergistic effect of photodynamic and photothermal therapy. The photosensitive dimer can efficiently produce type-I reactive oxygen species (ROS) by photodynamic therapy in hypoxic tumor tissue, leading to pyroptosis by direct cell membrane damage, which is further reinforced by its photothermal effect. Furthermore, the enhanced ICD effect based on the dimer can completely eliminate the primary tumor on the seventh day of treatment and can also boost systemic antitumor immunity by generating immune memory, which is demonstrated by the superior antitumor therapeutic effects on both solid tumors and metastatic tumors when healing 4T1 tumor mouse models with poor immunogenicity.

PD-1/PD-L1 pathway: A double-edged sword in periodontitis

Periodontitis is a disease caused by infection and immunological imbalance, which often leads to the destruction of periodontal tissue. Programmed death protein 1 (PD-1) and its ligand: programmed death ligand 1 (PD-L1) are important "immune checkpoint" proteins that have a negative regulatory effect on T cells and are targets of immunotherapy. Studies have shown that the expression of PD-1 and PD-L1 in patients with periodontitis is higher than that in healthy individuals. The keystone pathogen Porphyromonas gingivalis (P. gingivalis) is believed to be the main factor driving the upregulation of PD-1/PD-L1. High expression of PD-1/PD-L1 can inhibit the inflammatory response and reduce the destruction of periodontal supporting tissues, but conversely, it can promote the "immune escape" of P. gingivalis, thus magnifying infections. In addition, the PD-1/PD-L1 pathway is also associated with various diseases, such as cancer and Alzheimer's disease. In this review, we discuss the influence and mechanism of the PD-1/PD-L1 pathway as a "double-edged sword" affecting the occurrence and development of periodontitis, as well as its function in periodontitis-related systemic disorders. The PD-1/PD-L1 pathway could be a new avenue for periodontal and its related systemic disorders therapy.

Efficacy of PD-1/PD-L1 inhibitors in gastric or gastro-oesophageal junction cancer based on clinical characteristics: a meta-analysis

PURPOSE

Programmed death-1 (PD-1) and its ligand (PD-L1) inhibitors have been reported in several clinical trials for gastric cancer and gastroesophageal junction cancer (GC/GEJC). We presently carried out a meta analysis to evaluate the potency of PD-1/PD-L1 inhibitors in advanced GC/GEJC individuals with different clinical features and to determine patients more probably benefiting from the treatment.

METHODS

Randomized clinical trials (RCTs) in databases that compared PD-1/PD-L1 inhibitors to chemotherapy in patients with GC/GEJC published before May 2022 were retrieved. Basic characteristics were extracted from the included studies as well as hazard ratios (HR) and 95 percent confidence intervals (CI) for all individuals and subgroups. The inverse variance weighting method was used to evaluate pooled treatment data.

FINDINGS

Four RCTs involving 2,253 individuals were included. The results suggested that PD-1/PD-L1 inhibitors substantially enhanced overall survival (OS) (HR, 0.91; CI 95%, 0.83-1.00; p = 0.04) but not progression free survival (PFS) (HR, 1.17; CI 95%, 0.83-1.64; p = 0.38) in GC/GEJC individuals compared with chemotherapy. Significantly improved OS was observed in individuals aged < 65 years (HR, 0.84; p = 0.003), and men (HR, 0.88; p = 0.02), but not in individuals aged ≥ 65 years (HR, 0.97; p = 0.62), and women (HR, 0.98; p = 0.82).

IMPLICATIONS

PD-1/PD-L1 inhibitors improve OS but not PFS compared with chemotherapy in GC/GEJC. Age and sex could be used to predict the treatment potency of PD-1/PD-L1 inhibitors in GC/GEJC.

Preclinical development of a vaccine-based immunotherapy regimen (VBIR) that induces potent and durable T cell responses to tumor-associated self-antigens

The development of therapeutic cancer vaccines remains an active area, although previous approaches have yielded disappointing results. We have built on lessons from previous cancer vaccine approaches and immune checkpoint inhibitor research to develop VBIR, a vaccine-based immunotherapy regimen. Assessment of various technologies led to selection of a heterologous vaccine using chimpanzee adenovirus (AdC68) for priming followed by boosts with electroporation of DNA plasmid to deliver T cell antigens to the immune system. We found that priming with AdC68 rapidly activates and expands antigen-specific T cells and does not encounter pre-existing immunity as occurs with the use of a human adenovirus vaccine. The AdC68 vector does, however, induce new anti-virus immune responses, limiting its use for boosting. To circumvent this, boosting with DNA encoding the same antigens can be done repetitively to augment and maintain vaccine responses. Using mouse and monkey models, we found that the activation of both CD4 and CD8 T cells was amplified by combination with anti-CTLA-4 and anti-PD-1 antibodies. These antibodies were administered subcutaneously to target their distribution to vaccination sites and to reduce systemic exposure which may improve their safety. VBIR can break tolerance and activate T cells recognizing tumor-associated self-antigens. This activation lasts more than a year after completing treatment in monkeys, and inhibits tumor growth to a greater degree than is observed using the individual components in mouse cancer models. These results have encouraged the testing of this combination regimen in cancer patients with the aim of increasing responses beyond current therapies.

LncRNA TINCR impairs the efficacy of immunotherapy against breast cancer by recruiting DNMT1 and downregulating MiR-199a-5p via the STAT1-TINCR-USP20-PD-L1 axis

Although programmed death-ligand 1 (PD-L1) inhibitors have achieved some therapeutic success in breast cancer, their efficacy is limited by low therapeutic response rates, which is closely related to the immune escape of breast cancer cells. Tissue differentiation inducing non-protein coding RNA (TINCR), a long non-coding RNA, as an oncogenic gene associated with the progression of various malignant tumors, including breast cancer; however, the role of TINCR in tumor immunity, especially in breast cancer, remains unclear. We confirmed that TINCR upregulated PD-L1 expression in vivo and in vitro, and promoted the progression of breast cancer. Next, we revealed that TINCR knockdown can significantly improve the therapeutic effect of PD-L1 inhibitors in breast cancer in vivo. Mechanistically, TINCR recruits DNMT1 to promote the methylation of miR-199a-5p loci and inhibit its transcription. Furthermore, in the cytoplasm, TINCR potentially acts as a molecular sponge of miR-199a-5p and upregulates the stability of USP20 mRNA through a competing endogenous RNA (ceRNA) regulatory mechanism, thus promoting PD-L1 expression by decreasing its ubiquitination level. IFN-γ stimulation activates STAT1 by phosphorylation, which migrates into the nucleus to promote TINCR transcription. This is the first study to describe the regulatory role of TINCR in breast cancer tumor immunity, broadening the current paradigm of the functional diversity of TINCR in tumor biology. In addition, our study provides new research directions and potential therapeutic targets for PD-L1 inhibitors in breast cancer.

Rational design of a Nivolumab-based ANTI-PD-1 single chain variable fragment that blocks the interaction between PD-1 expressed on T-CELLS and PD-L1 ON CHO cells

Antibodies that block the interaction between PD-1 expressing T-cells and cancer cells expressing PD-L1 play a central role in contemporary immunotherapy regimes [1-3]. We previously reported the isolation of a single chain variable fragment (scFv) of the monoclonal anti-PD-1 antibody Nivolumab, that binds to purified PD-1 and blocked its interaction with PD-L1 [4]. This anti-PD-1 scFv did not, however, function in a cell-based assay designed to detect the disruption of the PD-1/PD-L1 interaction, a result likely due to its poor solubility in tissue culture media. Herein we report that following a series of structure-based rational design analyses, including Aggreescan3D, we have isolated a variant of the anti-PD-1 scFv having significantly improved solubility in tissue culture medium. Moreover, this soluble anti-PD-1 scFv variant disrupted the interaction between PD-1 expressed on Jurkat Cells and PD-L1 expressed on CHO cells. These findings are discussed in terms of the related observation that the residues mutated to form the anti-PD-1 variant are conserved in many other scFvs; thus, the properties of a range of scFvs will likely be enhanced by similar mutations of the conserved residues.

PD-1 signalling defines and protects leukaemic stem cells from T cell receptor-induced cell death in T cell acute lymphoblastic leukaemia

T cell acute lymphoblastic leukaemia (T-ALL) is an aggressive malignancy with poor prognosis, but a decisive marker and effective treatment for leukaemia stem cells (LSCs) remain unclear. Here, using lineage tracing, limiting dilution assays and in vivo live imaging approaches, we identify rare inhibitory receptor programmed cell death 1 (PD-1)-expressing cells that reside at the apex of leukaemia hierarchy for initiation and relapse in T-ALL. Ablation of PD-1-expressing cells, deletion of PD-1 in T-ALL cells or blockade of PD-1 or PD-1 ligand 1 significantly eradicated LSCs and suppressed disease progression. Combination therapy using PD-1 blockade and chemotherapy substantially extended the survival of mice engrafted with mouse or human T-ALL cells. Mechanistically, PD-1⁺ LSCs had high NOTCH1-MYC activity for disease initiation. Furthermore, PD-1 signalling maintained quiescence and protected LSCs against T cell receptor-signal-induced apoptosis. Overall, our data highlight the hierarchy of leukaemia by identifying PD-1⁺ LSCs and provide a therapeutic approach for the elimination of LSCs through PD-1 blockade in T-ALL.

Enhancement of anti-tumor efficacy of immune checkpoint blockade by alpha-TEA

Cancer immunotherapy such as anti-PD-1/anti-PD-L1 immune checkpoint blockade (ICB) can provide significant clinical benefit in patients with advanced malignancies. However, most patients eventually develop progressive disease, thus necessitating additional therapeutic options. We have developed a novel agent, a-TEA-LS, that selectively induces tumor cell death while sparing healthy tissues, leading to increased activation of tumor-reactive T cells and tumor regression. In the current study, we explored the impact of combined a-TEA-LS + ICB in orthotopic and spontaneously arising murine models of mammary carcinoma. We found that a-TEA-LS + ICB led to increased production of pro-inflammatory cytokines that were associated with a reduction in tumor growth and prolonged survival. Together, these data demonstrate the potential utility of a-TEA-LS + ICB for the treatment of breast cancer and provide the rationale for clinical translation of this novel approach.

Ovarian cancer-associated immune exhaustion involves SPP1+ T cell and NKT cell, symbolizing more malignant progression

Background

Ovarian cancer (OC) is highly heterogeneous and has a poor prognosis. A better understanding of OC biology could provide more effective therapeutic paradigms for different OC subtypes.

Methods

To reveal the heterogeneity of T cell-associated subclusters in OC, we performed an in-depth analysis of single-cell transcriptional profiles and clinical information of patients with OC. Then, the above analysis results were verified by qPCR and flow cytometry examine.

Results

After screening by threshold, a total of 85,699 cells in 16 ovarian cancer tissue samples were clustered into 25 major cell groups. By performing further clustering of T cell-associated clusters, we annotated a total of 14 T cell subclusters. Then, four distinct single-cell landscapes of exhausted T (Tex) cells were screened, and SPP1 + Tex significantly correlated with NKT cell strength. A large amount of RNA sequencing expression data combining the CIBERSORTx tool were labeled with cell types from our single-cell data. Calculating the relative abundance of cell types revealed that a greater proportion of SPP1 + Tex cells was associated with poor prognosis in a cohort of 371 patients with OC. In addition, we showed that the poor prognosis of patients in the high SPP1 + Tex expression group might be related to the suppression of immune checkpoints. Finally, we verified in vitro that SPP1 expression was significantly higher in ovarian cancer cells than in normal ovarian cells. By flow cytometry, knockdown of SPP1 in ovarian cancer cells could promote tumorigenic apoptosis.

Conclusion

This is the first study to provide a more comprehensive understanding of the heterogeneity and clinical significance of Tex cells in OC, which will contribute to the development of more precise and effective therapies.

Cascade Immune Activation of Self-Delivery Biomedicine for Photodynamic Immunotherapy Against Metastatic Tumor

Photodynamic therapy (PDT) can generate reactive oxygen species (ROS) to cause cell apoptosis and induce immunogenic cell death (ICD) to activate immune response, becoming a promising antitumor modality. However, the overexpressions of indoleamine 2,3-dioxygenase (IDO) and programmed cell death ligand 1 (PD-L1) on tumor cells would reduce cytotoxic T cells infiltration and inhibit the immune activation. In this paper, a simple but effective nanosystem is developed to solve these issues for enhanced photodynamic immunotherapy. Specifically, it has been constructed a self-delivery biomedicine (CeNB) based on photosensitizer chlorine e6 (Ce6), IDO inhibitor (NLG919), and PD1/PDL1 blocker (BMS-1) without the need for extra excipients. Of note, CeNB possesses fairly high drug content (nearly 100%), favorable stability, and uniform morphology. More importantly, CeNB-mediated IDO inhibition and PD1/PDL1 blockade greatly improve the immunosuppressive tumor microenvironments to promote immune activation. The PDT of CeNB not only inhibits tumor proliferation but also induces ICD response to activate immunological cascade. Ultimately, self-delivery CeNB tremendously suppresses the tumor growth and metastasis while leads to a minimized side effect. Such simple and effective antitumor strategy overcomes the therapeutic resistance against PDT-initiated immunotherapy, suggesting a potential for metastatic tumor treatment in clinic.

Direct AKT activation in tumor-infiltrating lymphocytes markedly increases interferon-γ (IFN-γ) for the regression of tumors resistant to PD-1 checkpoint blockade

PD-1 immune checkpoint blockade against inhibitory receptors such as receptor programmed cell death-1 (PD-1), has revolutionized cancer treatment. Effective immune reactivity against tumour antigens requires the infiltration and activation of tumour-infiltrating T-cells (TILs). In this context, ligation of the antigen-receptor complex (TCR) in combination with the co-receptor CD28 activates the intracellular mediator AKT (or PKB, protein kinase B) and its downstream targets. PD-1 inhibits the activation of AKT/PKB. Given this, we assessed whether the direct activation of AKT might be effective in activating the immune system to limit the growth of tumors that are resistant to PD-1 checkpoint blockade. We found that the small molecule activator of AKT (SC79) limited growth of a B16 tumor and an EMT-6 syngeneic breast tumor model that are poorly responsive to PD-1 immunotherapy. In the case of B16 tumors, direct AKT activation induced (i) a reduction of suppressor regulatory (Treg) TILs and (ii) an increase in effector CD8+ TILs. SC79 in vivo therapy caused a major increase in the numbers of CD4+ and CD8+ TILs to express interferon-γ (IFN-γ). This effect on IFN-γ expression distinguished responsive from non-responsive anti-tumor responses and could be recapitulated ex vivo with human T-cells. In CD4+FoxP3+Treg TILs, AKT induced IFN-γ expression was accompanied by a loss of suppressor activity, the conversation to CD4⁺ helper Th1-like TILs and a marked reduction in phospho-SHP2. In CD8+ TILs, we observed an increase in the phospho-activation of PLC-γ. Further, the genetic deletion of the transcription factor T-bet (Tbx21) blocked the increased IFN-γ expression on all subsets while ablating the therapeutic benefits of SC79 on tumor growth. Our study shows that AKT activation therapy acts to induce IFN-γ on CD4 and CD8 TILs that is accompanied by the intra-tumoral conversation of suppressive Tregs into CD4⁺Th1-like T-cells and augmented CD8 responses.

BET inhibition triggers antitumor immunity by enhancing MHC class I expression in head and neck squamous cell carcinoma

BET inhibition has been shown to have a promising antitumor effect in multiple tumors. However, the impact of BET inhibition on antitumor immunity was still not well documented in HNSCC. In this study, we aim to assess the functional role of BET inhibition in antitumor immunity and clarify its mechanism. We show that BRD4 is highly expressed in HNSCC and inversely correlated with the infiltration of CD8+ T cells. BET inhibition potentiates CD8+ T cell-based antitumor immunity in vitro and in vivo. Mechanistically, BRD4 acts as a transcriptional suppressor and represses the expression of MHC class I molecules by recruiting G9a. Pharmacological inhibition or genetic depletion of BRD4 potently increases the expression of MHC class I molecules in the absence and presence of IFN-γ. Moreover, compared to PD-1 blocking antibody treatment or JQ1 treatment individually, the combination of BET inhibition with anti-PD-1 antibody treatment significantly enhances the antitumor response in HNSCC. Taken together, our data unveil a novel mechanism by which BET inhibition potentiates antitumor immunity via promoting the expression of MHC class I molecules and provides a rationale for the combination of ICBs with BET inhibitors for HNSCC treatment.

Tumor extracellular vesicles mediate anti-PD-L1 therapy resistance by decoying anti-PD-L1

PD-L1⁺ tumor-derived extracellular vesicles (TEVs) cause systemic immunosuppression and possibly resistance to anti-PD-L1 antibody (αPD-L1) blockade. However, whether and how PD-L1⁺ TEVs mediate αPD-L1 therapy resistance is unknown. Here, we show that PD-L1⁺ TEVs substantially decoy αPD-L1 and that TEV-bound αPD-L1 is more rapidly cleared by macrophages, causing insufficient blockade of tumor PD-L1 and subsequent αPD-L1 therapy resistance. Inhibition of endogenous production of TEVs by Rab27a or Coro1a knockout reverses αPD-L1 therapy resistance. Either an increased αPD-L1 dose or macrophage depletion mediated by the clinical drug pexidartinib abolishes αPD-L1 therapy resistance. Moreover, in the treatment cycle with the same total treatment dose of αPD-L1, high-dose and low-frequency treatment had better antitumor effects than low-dose and high-frequency treatment, induced stronger antitumor immune memory, and eliminated αPD-L1 therapy resistance. Notably, in humanized immune system mice with human xenograft tumors, both increased αPD-L1 dose and high-dose and low-frequency treatment enhanced the antitumor effects of αPD-L1. Furthermore, increased doses of αPD-L1 and αPD-1 had comparable antitumor effects, but αPD-L1 amplified fewer PD-1⁺ Treg cells, which are responsible for tumor hyperprogression. Altogether, our results reveal a TEV-mediated mechanism of αPD-L1-specific therapy resistance, thus providing promising strategies to improve αPD-L1 efficacy.

Immunomodulating Hydrogels as Stealth Platform for Drug Delivery Applications

Non-targeted persistent immune activation or suppression by different drug delivery platforms can cause adverse and chronic physiological effects including cancer and arthritis. Therefore, non-toxic materials that do not trigger an immunogenic response during delivery are crucial for safe and effective in vivo treatment. Hydrogels are excellent candidates that can be engineered to control immune responses by modulating biomolecule release/adsorption, improving regeneration of lymphoid tissues, and enhancing function during antigen presentation. This review discusses the aspects of hydrogel-based systems used as drug delivery platforms for various diseases. A detailed investigation on different immunomodulation strategies for various delivery options and deliberate upon the outlook of such drug delivery platforms are conducted.

Thyroid Hormone Induces Oral Cancer Growth via the PD-L1-Dependent Signaling Pathway

Oral cancer is a fatal disease, and its incidence in Taiwan is increasing. Thyroid hormone as L-thyroxine (T₄) stimulates cancer cell proliferation via a receptor on integrin αvβ3 of plasma membranes. It also induces the expression of programmed death-ligand 1 (PD-L1) and cell proliferation in cancer cells. Thyroid hormone also activates β-catenin-dependent cell proliferation in cancer cells. However, the relationship between PD-L1 and cancer proliferation is not fully understood. In the current study, we investigated the role of inducible thyroid hormone-induced PD-L1-regulated gene expression and proliferation in oral cancer cells. Thyroxine bound to integrin αvβ3 to induce PD-L1 expressions via activation of ERK1/2 and signal transducer and activator of transcription 3 (STAT3). Inactivated STAT3 inhibited PD-L1 expression and nuclear PD-L1 accumulation. Inhibition of PD-L1 expression reduced β-catenin accumulation. Furthermore, nuclear PD-L1 formed a complex with nuclear proteins such as p300. Suppression PD-L1 expression by shRNA blocked not only expression of PD-L1 and β-catenin but also signal transduction, proliferative gene expressions, and cancer cell growth. In summary, thyroxine via integrin αvβ3 activated ERK1/2 and STAT3 to stimulate the PD-L1-dependent and β-catenin-related growth in oral cancer cells.

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

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