Coordinated regulation of myeloid cells by tumours. Nat Rev Immunol. 2012;12:253-268. [PMID: 22437938 DOI: 10.1038/nri3175]

Notch signaling and cancer: Insights into chemoresistance, immune evasion, and immunotherapy

The Notch signaling pathway is a fundamental and highly conserved cell-to-cell communication system vital for embryonic development and tissue maintenance. However, its dysregulation has been associated with the initiation, progression, and chemoresistance of various cancers. In this comprehensive review, we will take an in-depth look at the multiple roles of the Notch family in cancer pathogenesis, immune response, and resistance to chemotherapy. We delve into the complicated mechanisms by which Notch signaling promotes tumor growth and development, including its influence on TME remodeling and immune evasion strategies. We will also be discussing recent studies that shed light on the connection between cancer stemness and chemoresistance mediated through the activation of Notch signaling pathways. Elucidation of the interplay between the Notch pathway and major constituents of the TME, including immune cells and cancer-associated fibroblasts, is necessary for the development of targeted therapies against Notch-driven tumors. We further discuss the potential of targeting Notch signaling alone or in combination with standard chemotherapy and immunotherapy as a potent strategy to overcome chemoresistance and improve patient outcomes. We conclude by discussing the challenges and future prospects of using Notch signaling as a therapeutic target in cancer treatment, focusing on how precision medicine and combination approaches are important.

Pediatric gliomas immunity challenges and immunotherapy advances

Pediatric gliomas, the most frequent brain tumors in children, are characterized by heterogeneity and a unique tumor immune microenvironment. They are categorized into different subtypes, including low-grade gliomas like pilocytic astrocytomas and high-grade gliomas such as diffuse midline gliomas and diffuse intrinsic pontine gliomas, each exhibiting distinct immunological profiles. The tumor immune microenvironment in pediatric gliomas is shaped by cellular and non-cellular components, including immune cells, cytokines, and the extracellular matrix, involved in tumor progression, immune evasion, and response to therapy. While pediatric low-grade gliomas often display an immunosuppressed microenvironment, high-grade gliomas are characterized by complex immune infiltrates and intricate immunosuppressive mechanisms. The blood-brain barrier further obscures immune cell recruitment and therapeutic delivery. Despite advances in understanding adult gliomas, the immunobiology of pediatric tumors is poorly investigated, with limited data on the interactions between glioma cells and immune populations such as T and natural killer cells, as well as tumor-associated macrophages. Herein, we provide an update of the current knowledge on tumor immune microenvironment interactions in pediatric gliomas, highlighting the immunosuppressive mechanisms and emerging immunotherapeutic strategies aiming at overcoming these barriers to improve clinical outcomes for affected children.

T-lymphocytes suppression by CD14+ monocytes with high expression of ULK2 in patients with multiple myeloma

BACKGROUND

Multiple myeloma (MM), a plasma cell malignancy, remains incurable and is highly prone to relapse. Immunosuppressive cells in the bone marrow environment inhibit endogenous T-lymphocytes activity and reduce the efficacy immunotherapies. Abnormal bone marrow monocytes in MM have been associated with inferior outcomes. This study explored the mechanism of T-lymphocytes suppression by bone marrow CD14+ monocytes in MM.

METHODS

Single-cell RNA sequence data (GSE124310) derived from MM samples were analyzed. CD14+ monocytes from the bone marrow of patients with newly-diagnosed MM were detected, and RNA sequencing was performed. Interactions between CD14+ monocytes and T-lymphocytes, as along with the corresponding downstream signaling mechanism, were assessed through in vitro and in vivo experiments.

RESULTS

The alterations in MHC II signaling related to outgoing interaction were decreased in CD14 + monocytes from patients with MM. Abnormal numbers, defective antigen presentation, and downregulated surface co-stimulatory molecules in bone marrow CD14+ monocytes were also observed. RNA sequencing identified upregulated expression of Unc-51 like autophagy activating kinase 2 (ULK2) in these monocytes, a protein involved in the antigen processing and presentation pathway. CD14+ monocytes from patients with NDMM suppressed T-lymphocyte activity, and treatment of CD14+ monocytes with a ULK1/ULK2 inhibitor alleviated this suppression. MM xenograft model showed that CD14+ monocytes high-expressing ULK2 suppressed T-lymphocytes and promoted tumor growth.

CONCLUSION

We demonstrated that CD14+ monocytes from MM can disrupt the delivery of antigenic peptides through the antigen processing and presentation pathway. This disruption affects T-lymphocytes activity and attenuates their ability to kill malignant cells and secrete cytokines. These findings lay the foundation for understanding the immuno-suppressive environment in MM, improving the efficacy of immunotherapy based on T-lymphocytes, and developing new therapeutic targets.

Near-infrared photoimmunotherapy: basics and clinical application

Use of antibody-drug conjugates (ADCs) is rapidly increasing in the field of oncology. While ADCs exhibit strong and cell-selective cytotoxicity, they do not show spatial selectivity. Near-infrared photoimmunotherapy (NIR-PIT, Alluminox™) utilizes photoactivatable ADCs, that is, antibody-photoabsorber conjugates (APCs). The photoabsorber used in NIR-PIT, IRDye700DX (IR700), is activated by light of ~690 nm wavelength. APCs, usually administered by intravenous injection, bind to the target cell surface, and subsequent excitation-light illumination dramatically changes the status of IR700 from hydrophilic to hydrophobic, inducing aggregation of the APC-target molecule complex and cell burst. Dying cells release neoantigens as well as damage-associated molecular patterns, resulting in immunogenic cell death (ICD). Based on the favorable results of clinical trials, epidermal growth factor-targeted NIR-PIT has been performed in Japan since 2021 for patients with unresectable head and neck cancers (HNCs). Since pain and local edema are frequent adverse events (AEs), various measures have been taken against these AEs. Because NIR-PIT induces ICD, combining NIR-PIT with immune checkpoint inhibitor (ICI) therapy is thought to be a rather effective strategy. NIR-PIT could also locally destroy immune suppressor cells, such as regulatory T cells, in the tumor microenvironment. Currently, numerous clinical trials are under way to evaluate the efficacy of NIR-PIT as well as of combined NIR-PIT plus ICI therapy. In this review article, we describe the basics of NIT-PIT, results of translational experiments, current clinical application of NIT-PIT in HNCs, and relevant ongoing clinical trials.

The complement system and kidney cancer: pathogenesis to clinical applications

Kidney cancer poses unique clinical challenges because of its resistance to conventional treatments and its tendency to metastasize. The kidney is particularly susceptible to dysfunction of the complement system, an immune network that tumors often exploit. Recent discoveries have highlighted that the complement system not only plays a crucial role in immune surveillance and defense in the circulatory system, but also functions intracellularly and autonomously. This concept has shifted the focus of investigation toward understanding how complement proteins influence cancer progression by regulating the tumor microenvironment (TME), cell signaling, proliferation, metabolism, and the immune response. With the complement system and its inhibitors emerging as a promising new class of immunotherapeutics and potential complement-targeted treatments advancing through development pipelines and clinical trials, this Review provides a timely examination of how harnessing the complement system could lead to effective tumor treatments and how to strategically combine complement inhibitors with other cancer treatments, offering renewed hope in the fight against kidney cancer.

Tumor-infiltrating and circulating B cells mediate local and systemic immunomodulatory mechanisms in Glioblastoma

BACKGROUND

Glioblastoma (GBM) demonstrates extensive immunomodulatory mechanisms that challenge effective therapeutic interventions. These phenomena extend well beyond the tumor microenvironment (TME) and are reflected in the circulating immunophenotype. B lymphocytes (B cells) have received limited attention in GBM studies despite their emerging importance in mediating both local and systemic immune responses. Recent findings highlight the complex regulatory interactions between B cells and other immune cell populations, including tumor-infiltrating macrophages (TAMs), myeloid-derived suppressor cells (MDSCs), and other infiltrating lymphocytes (TILs). B cells are believed to hinder the efficacy of modern immunotherapy strategies focusing on T cells.

METHODS

This is a focused review of available evidence regarding B cells in GBM through January 2025.

RESULTS

Peripheral blood reflects a systemically dampened immune response, with sustained lymphopenia, increased plasma cells, and dysfunctional memory B cells. The tumor immune landscape is enriched in cells of B-lineage. Subsets of poorly characterized B regulatory cells (Bregs) populate the TME, developing their phenotype due to their proximity to MDSCs, TAMs, and tumoral cells. The Bregs inhibit CD8+ T activity and may have potential prognostic significance.

CONCLUSION

Understanding the role of B cells, how they are recruited, and their differentiation shifted towards an immunomodulatory role could inform better therapeutic strategies and unleash their full antitumoral potential in GBM.

Effect of calcitriol on myeloid-derived suppressor cells in physiological aging

The active hormonal form of vitamin D, 1,25(OH)2D, regulates many components of the immune system and previous research shows that 1,25(OH)2D reduces the number and suppressive activity of MDSCs in tumors. This study aimed to evaluate the effects of calcitriol treatment on MDSCs in aged mice. We showed that aged BALB/c and CD1 mice exhibited increased levels of CD11b+Gr1+ cells in both the spleen and bone marrow compared to young mice. These cells displayed a less mature phenotype marked by reduced F4/80 expression and demonstrated robust T cell suppressive activity, as evidenced by their ability to inhibit the production of IFNγ and TNFα. Treatment of aged mice with calcitriol, administered twice weekly at a dose equivalent to 1 µg/kg for 4 weeks, significantly increased the population of CD11b+Gr1+ cells in the spleen, but not in the bone marrow of the animals, and promoted their differentiation into a more mature phenotype characterized by elevated F4/80 expression. In addition, calcitriol-treated aged mice exhibited significantly improved T cell responses, as indicated by increased IFNγ production upon specific antigen stimulation compared to the control group of mice. In vitro, calcitriol treatment of bone marrow-derived MDSCs similarly enhanced F4/80 expression without altering other markers such as CD11b, CD11c, or MHCII, and led to reduced expression of reactive oxygen species by these cells. Our study highlights the consistency of MDSC expansion across inbred and outbred mouse strains and supports the immunomodulatory role of calcitriol in promoting MDSC maturation and alleviating immune suppression in aging.

Angiogenesis and immune microenvironment in triple-negative breast cancer: Targeted therapy

Triple-negative breast cancer (TNBC) is a highly aggressive breast cancer subtype that typically lacks effective targeted therapies, leading to limited treatment options. Chemotherapy remains the primary treatment modality; however, in recent years, new immunotherapy approaches, such as immune checkpoint inhibitors, have shown positive results in some patients. Although the development of TNBC is closely associated with BRCA gene mutations, the tumor immune microenvironment (TIME) plays a crucial role in tumor progression and immune escape. Tumor angiogenesis, the accumulation of immunosuppressive cells, and alterations in immune molecules collectively shape an environment unfavorable for anti-tumor immune responses. Tumor-associated macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs) promote immune escape by secreting immunosuppressive factors. Therefore, combination strategies of anti-angiogenic and immune checkpoint inhibitory therapies have shown synergistic effects in clinical trials, while new targeted therapies such as TGF-β inhibitors and IL-1β inhibitors offer new options for TNBC treatment. With the development of personalized medicine, combining immunotherapy and targeted therapies brings new hope for TNBC patients.

Not all colon cancer patients with preoperative hyperinflammatory status are at high risk of muscle loss and poor prognosis

PURPOSE

Growing evidence indicates that preoperative hyperinflammation is an independent risk factor for postoperative sarcopenia and poor prognosis in patients with colon cancer. However, inflammation fluctuates with tumor burden and immune status after surgery, and its role in muscle degradation remains unclear. This study aimed to explore the impact of different inflammatory trajectories on muscle wasting.

METHODS

This retrospective study included 193 patients who are diagnosed with stage II or III colon cancer between 2015 and 2021. The preoperative and postoperative neutrophil-to-lymphocyte ratio (NLR) and prognostic immunological and nutritional index (PINI) were used to assess inflammation, and the subjects divided into four groups: a group with consistently low inflammation (G1), a group with initially high but postoperative decreased inflammation (G2), a group with initially low but postoperative increased inflammation (G3), and a group with consistently high inflammation (G4). Logistic regression identified risk factors for postoperative sarcopenia, while multivariate linear regression assessed the impact of inflammation on skeletal muscle index (SMI%) and density loss rate (SMD%). Cox models calculated overall survival (OS) and recurrence-free survival (RFS).

RESULTS

For all the assessed markers, the SMI% and SMD% in G4 significantly increased compared to G1 (P < 0.05), while G2 and G3 showed no significant change at 12 months (P > 0.05). Elevated inflammation was an independent risk factor for postoperative sarcopenia (P < 0.05). Postoperative sarcopenia and PINI in G4 independently influenced OS and RFS.

CONCLUSIONS

Only patients with persistent postoperative inflammation, not all patients with preoperative inflammation, are at increased risk for muscle wasting and poor prognosis. These findings suggest that modulating postoperative inflammation could reduce muscle loss and improve survival; these findings guide the future development of anti-inflammatory therapies for suitable populations.

Early metastasis is characterized by Gr1+ cell dysregulation and is inhibited by immunomodulatory nanoparticles

Cancer metastasis is supported by dysregulated myeloid-derived suppressor cells, but myeloid cells are highly heterogeneous populations with distinct subsets that may support or inhibit tumor cell colonization. We hypothesize that Gr1+ myeloid cells transform in phenotype to support tumor cell colonization at the metastatic niche. In the 4T1 model of metastatic breast cancer, we investigate changes in the composition and phenotype of Gr1+ cells between premetastatic disease and early metastasis. Gr1+ cells in the lung were found to transition towards immunosuppressive and tumor-supportive phenotypes with disease progression. While the composition of myeloid cells becomes dysregulated systemically, cells in the blood do not develop tumor-supportive phenotypes, indicating that protumor functions are specific to the lung. In vitro assays demonstrate that Gr1+ cells from early metastatic lungs support tumor cell survival, migration, and proliferation, which is linked to chitinase-3-like protein 1 (CHI3L1) signaling. The intravenous injection of polymeric nanoparticles reprograms Gr1+ cell phenotypes, reduces the secretion of CHI3L1, and inhibits metastasis. These findings indicate that dysregulated Gr1+ cells are a therapeutic target for early metastasis and can be targeted with polymeric nanoparticles.

Inhibiting glycolysis facilitated checkpoint blockade therapy for triple-negative breast cancer

Cancer cells are characterized by their altered energy metabolism. A hallmark of cancer metabolism is aerobic glycolysis, also called the Warburg effect. Hexokinase 2 (HK2), a crucial glycolytic enzyme converting glucose to glucose-6-phosphate, has been identified as a central player in the Warburg effect. Deletion of HK2 decreases cancer cell proliferation in animal models without explicit side effects, suggesting that targeting HK2 is a promising strategy for cancer therapy. In this study, we discovered a correlation between HK2 and the tumor immune response in triple-negative breast cancer. Inhibition of HK2 led to a reduction in G-CSF expression in 4T1 cells and a decrease in the development of myeloid-derived suppressor cells which, in turn, enhanced T cell immunity and prolonged the survival of 4T1 tumor-bearing mice. Furthermore, the HK2 inhibitor 3-BrPA improved the therapeutic efficacy of anti-PD-L1 therapy in 4T1 tumor-bearing mouse models. This study highlights the potential of glycolysis-targeting interventions as a novel treatment strategy, which can be combined with immunotherapy for the treatment of triple-negative breast cancer.

EXOSC5: a novel biomarker for poor prognosis in lung adenocarcinoma

BACKGROUND

Exosome complex gene 5 (EXOSC5), a member of the exosome complex family, is highly tumorigenic in various cancers. However, its prognostic value and underlying mechanisms in lung adenocarcinoma (LUAD) remain unclear.

METHODS

We analysed LUAD data from The Cancer Genome Atlas (TCGA) via bioinformatics tools. Logistic regression was used to assess the associations between clinical information and EXOSC5 expression in LUAD patients. EXOSC5 expression was validated by immunohistochemistry (IHC) and western blotting, and its functional role was investigated through gene set enrichment analysis (GSEA) and in vitro experiments.

RESULTS

EXOSC5 was significantly upregulated in LUAD and associated with poor prognosis. The risk model based on EXOSC5 expression outperformed the traditional staging system for prognosis prediction. EXOSC5 promoted tumor progression by regulating the cell cycle, proliferation, and immune cell infiltration. High EXOSC5 expression was correlated with resistance to anti-PD1 immunotherapy.

CONCLUSION

EXOSC5 is a novel oncogenic factor in LUAD that promotes tumor progression and immune evasion and may serve as a prognostic biomarker and therapeutic target.

Exosomes delivering miR-129-5p combined with sorafenib ameliorate hepatocellular carcinoma progression via the KCTD1/HIF-1α/VEGF pathway

BACKGROUND

Potassium channel tetramerization domain-containing 1 (KCTD1) plays a critical role in transcriptional regulation and adipogenesis, but its significance in hepatocellular cancer (HCC) has not been reported.

METHODS

Immunohistochemistry, Western blotting and quantitative real-time PCR analysis were performed to assess the expression of KCTD1 and related genes in HCC cells. MTT assays, colony formation, cell migration, invasion and the in-vivo mouse models were utilized to evaluate the function of KCTD1 in HCC progression. Co-immunoprecipitation, chromatin immunoprecipitation and luciferase reporter assays were conducted to elucidate the molecular mechanisms of KCTD1 in HCC.

RESULTS

KCTD1 expression was increased in human HCC tissues and closely associated with advanced tumor stages. KCTD1 overexpression enhanced growth, migration, and invasion of Huh7 and HepG2 cells both in vitro and in vivo, while KCTD1 knockdown reversed these effects in MHCC97H cells. Mechanistically, KCTD1 interacted with hypoxia-inducible factor 1 alpha (HIF-1α) and enhanced HIF-1α protein stability with the inhibited prolyl-hydroxylases (PHD)/Von Hippel-Lindau (VHL) pathway, consequently activating the Vascular Endothelial Growth Factor (VEGF)/VEGFR2 pathway in HCC cells. Sorafenib and KCTD1 knockdown synergistically inhibited intrahepatic tumor growth following in situ injection of MHCC97H cells. miR-129-5p downregulated KCTD1 by binding to KCTD1 3'UTR. Finally, 45 µg exosomes from miR-129-5p-overexpressing MHCC97H cells combined with 25 mg/kg sorafenib to decrease HCC tumor size.

CONCLUSIONS

These results suggested that KCTD1 protects HIF-1α from degradation and activates the VEGF signaling cascade to enhance HCC progression. Therefore, KCTD1 may serve as a novel target of HCC and pave the way for an efficient combined therapy in advanced HCC.

Identification of M1 macrophage infiltration-related genes for immunotherapy in Her2-positive breast cancer based on bioinformatics analysis and machine learning

Over the past several decades, there has been a significant increase in the number of breast cancer patients. Among the four subtypes of breast cancer, Her2-positive breast cancer is one of the most aggressive breast cancers. In this study, we screened the differentially expressed genes from The Cancer Genome Atlas-Breast cancer database and analyzed the relationship between immune cell infiltration and differentially expressed genes using weighted gene co-expression network analysis. By constructing a module-trait relationships heatmap, the red module, which had the highest correlation value with M1 macrophages, was selected. Twenty hub genes were selected based on a protein-protein interaction network. Then, four overlapping M1 macrophage infiltration-related genes (M1 MIRGs), namely CCDC69, PPP1R16B, IL21R, and FOXP3, were obtained using five machine-learning algorithms. Subsequently, nomogram models were constructed to predict the incidence of Her2-positive breast cancer patients. The outer datasets and receiver operating characteristic curve analysis were used to validate the accuracy of the four M1 MIRGs and nomogram models. The average value of the area under the curve for the nomogram models was higher than 0.75 in both the training and testing sets. After that, survival analysis showed that higher expression of CCDC69, PPP1R16B, and IL21R were associated with overall survival of Her2-positive breast cancer patients. The expression of CCDC69 and PPP1R16B could lead to more benefits than the expression of IL21R and FOXP3 for immunotherapy. Lastly, we conducted immunohistochemistry staining to validate the aforementioned results. In conclusion, we found four M1 MIRGs that may be helpful for the diagnosis, prognosis, and immunotherapy of Her2-positive breast cancer.

Interplay between the complement system and other immune pathways in the tumor microenvironment

Tumor growth and spread are sustained by the tumor microenvironment. Inflammatory cells and pathways have a fundamental role in the tumor microenvironment, driving or conditioning the functional activation of other leukocyte subsets and favoring evasion of anti-tumor immunity. One of the inflammatory pathways contributing to cancer-related inflammation is the complement system. Complement has long been considered an immune mechanism associated with immunosurveillance. More recently it emerged as a tumor promoting pathway, due to direct effects on cancer cells or indirect effects via immunosuppression driven by myeloid cells. The role of complement in cancer is complex and ambiguous, and depends on the tumor type and stage, as well as other factors including oncogenic drivers, leukocyte infiltration, interactions with other tumor microenvironment components or tumor cells. Other factors of complexity include the source of complement molecules, its canonical or non-canonical extracellular functions, its potential intracellular activation, and the interaction with other systems, such as the coagulation or the microbiome. Preclinical studies generally demonstrate the involvement of complement activation in smouldering inflammation in cancer and promotion of an immunosuppressive environment. These studies paved the way for clinical trials aimed at enhancing the potential of immunotherapy, in particular by targeting complement-dependent myeloid-sustained immunosuppression. However, the complex role of complement in cancer and the multiplicity of complement players may represent stumbling blocks and account for failures of clinical trials, and suggest that further studies are required to identify patient subsets who may benefit from specific complement molecule targeting in combination with conventional therapies or immunotherapy. Here, we will discuss the anti- or pro-tumor role of complement activation in cancer, focusing on the interactions of complement with immune cells within the tumor microenvironment, in particular the myeloid compartment. Furthermore, we will examine the potential of complement targeting in cancer treatment, particularly in the context of macrophage reprogramming.

Senescence, NK cells, and cancer: navigating the crossroads of aging and disease

Cellular senescence, a state of stable cell cycle arrest, acts as a double-edged sword in cancer biology. In young organisms, it acts as a barrier against tumorigenesis, but in the aging population, it may facilitate tumor growth and metastasis through the senescence-associated secretory phenotype (SASP). Natural killer (NK) cells play a critical role in the immune system, particularly in the surveillance, targeting, and elimination of malignant and senescent cells. However, age-related immunosenescence is characterized by declining NK cell function resulting in diminished ability to fight infection, eliminate senescent cells and suppress tumor development. This implies that preserving or augmenting NK cell function may be central to defense against age-related degenerative and malignant diseases. This review explores the underlying mechanisms behind these interactions, focusing on how aging influences the battle between the immune system and cancer, the implications of senescent NK cells in disease progression, and the potential of adoptive NK cell therapy as a countermeasure to these age-related immunological challenges.

Myeloid cells in the microenvironment of brain metastases

Brain metastasis (BrM) from peripheral solid tumors has a high mortality rate and remains a daunting clinical challenge. In addition to the targeting of tumor cells, studies have focused on the regulation of the tumor microenvironment (TME) for BrM treatment. Here, through a review of recent studies, we revealed that myeloid infiltration is a common feature of the TME in BrMs from different primary sites even though the brain is regarded as an immune-privileged site and is always in an immunosuppressive state. Tumor-educated bone marrow progenitors, especially mesenchymal stem cells (MSCs), may impact the brain tropism and and phenotypic switching of myeloid cells. Additionally, chronic inflammation may be key factors regulating the immunosuppressive TME and myeloid cell reprogramming. Here, the role of myeloid cells in the formation of the TME and strategies for targeting these cells before and after BrM are reviewed, emphasizing the potential for the use of myeloid cells in BrM treatment. However, the direct relationship between the neuronal system and myeloid cell filtration is still unclear and worthy of further study.

In vitro and in vivo evaluation of anti-HER2 antibody conjugates labelled with 225Ac

BACKGROUND

Overexpression of human epidermal growth factor receptor type 2 (HER2) occurs in multiple carcinomas. For example, up to 20% of breast cancer cases are classified as HER2 positive (HER2+). Treatment of this condition typically involves immunotherapy using monoclonal antibodies, such as trastuzumab or pertuzumab. The precise targeting of monoclonal antibodies to HER2+ tumour lesions can be used as well in radioimmunotherapy to deliver medical radionuclides exactly to the afflicted area and therefore minimize radiation exposure of healthy tissues. In this study, DOTA conjugates of monoclonal antibodies trastuzumab and pertuzumab were prepared and tested in vitro. One of these, 225Ac-DOTA-pertuzumab, was also the subject of an ex vivo biodistribution study with normal as well as HER2+ and HER2- tumour-xenografted mice. This radioconjugate has not been previously described.

RESULTS

Three DOTA-conjugates of HER2 targeting monoclonal antibodies, one of trastuzumab and two of pertuzumab, were prepared and radiolabelled with 225Ac in different molar ratios. This procedure led to an optimisation of the preparation and radiolabelling process. The radioconjugates were shown to be highly stable in vitro in both fetal bovine serum and phosphate buffered saline under room temperature and decreased temperature for 10 days. In vitro cell studies with HER2-overexpressing cell-line (SKOV-3) and low HER2-expressing cell line (MDA-MB-231) proved that radioconjugates of both antibodies have high binding specificity and affinity towards HER2 receptors. These findings were confirmed for a novel radioconjugate 225Ac-DOTA-pertuzumab in an ex vivo biodistribution study, where uptake in HER2+ tumour was 50 ± 14% ID/g and HER2- tumour showed uptake comparable with healthy tissues (max. 5.0 ± 1.7% ID/g). The high uptake observed in the spleen can be attributed to the elimination of the antibody, as well as the use of an immunedeficient mouse strain (SCID).

CONCLUSIONS

During this study, the optimization of preparation and radiolabelling of HER2 targeting antibodies with 225Ac was accomplished. Furthermore, the radioconjugate 225Ac-DOTA-pertuzumab was prepared and evaluated for the first time. The radioconjugates of both tested antibodies demonstrated excellent qualities in terms of stability and HER2 receptor affinity. Initial ex vivo studies indicated that especially the radioconjugate 225Ac-DOTA-pertuzumab is a very promising candidate for further more detailed in vivo studies.

C3-Liposome Delivery of MUC1 Peptide and TLR Agonists Enhances Adaptive Immunity and Results in Sex-Based Tumor Growth Differences

Background: Mucin-1 (MUC1) is a glycoprotein that is hypoglycosylated and overexpressed in most adenocarcinomas, making it a promising target for cancer vaccines. Our group previously demonstrated that C3 (OPSS)-liposomes enhance antigen uptake by antigen-presenting cells (APCs) via the complement C3 pathway and, when combined with toll-like receptor (TLR) agonists, reduce tumor growth in murine cancer models. Methods: In the present study, we evaluate the immunogenicity of MUC1 peptide vaccines encapsulated in C3-liposomes, with and without TLR agonists, using MUC1-tolerant transgenic mice challenged with Lewis lung carcinoma (LLC.MUC1) cells. To assess vaccine effectiveness, tumor volumes were measured, and flow cytometry and ELISA and ELISPOT assays were used to assess the immune response. Results: Both male and female C57BL/6 transgenic mice vaccinated with MUC1 C3-liposomes developed significantly smaller tumors than those vaccinated with free MUC1 peptide or PBS. Notably, a sex-dependent response emerged in mice vaccinated with MUC1 C3-liposomes with TLR agonists (TLR4, TLR7/8, and TLR9); male mice exhibited greater tumor suppression than females. Flow cytometry analysis revealed that female mice had significantly higher levels of CD11b+, LY6C+, and LY6G+ MDSC cells, suggesting a potential mechanism for the sex difference. Additionally, MUC1 C3-liposome vaccination elicited robust adaptive immune responses, including significantly higher levels of IFN-γ-producing T cells and MUC1-specific IgG antibodies compared to non-encapsulated MUC1 or TLR adjuvant-only formulations. Conclusions: These findings underscore the potential of C3-liposome-based antigen vaccines to enhance anti-tumor immunity and highlight the impact of sex differences in vaccine efficacy.

Unraveling the Complexities of Myeloid-Derived Suppressor Cells in Inflammatory Bowel Disease

Myeloid-derived suppressor cells (MDSCs) regulate immune responses in many pathological conditions, one of which is inflammatory bowel disease (IBD), an incurable chronic disorder of the digestive tract and beyond. The pathophysiology of IBD remains unclear, likely involving aberrant innate and adaptive immunity. Studies have reported altered population of MDSCs in patients with IBD. However, their distribution varies among patients and different preclinical models of IBD. The expansion and activation of MDSCs are likely driven by various stimuli during intestinal inflammation, but the in-depth mechanisms remain poorly understood. The role of MDSCs in the pathogenesis of IBD appears to be paradoxical. In addition to intestinal inflammation, suppressive MDSCs may promote colitis-to-colon cancer transition. In this Review, we summarize recent progresses on the features, activation, and roles of MDSCs in the development of IBD and IBD-associated colon cancer.

Unraveling Th subsets: insights into their role in immune checkpoint inhibitor therapy

T helper (Th) cell subsets play pivotal roles in regulating immune responses within the tumor microenvironment, influencing both tumor progression and anti-tumor immunity. Among these subsets, Th1 cells promote cytotoxic responses through the production of IFN-γ, while Th2 cells and regulatory T cells (Tregs) exert immunosuppressive effects that support tumor growth. Th9 and Th17 cells have context-dependent roles, contributing to both pro-inflammatory and regulatory processes in tumor immunity. Tumor antigen-specific T cells within the tumor microenvironment often exhibit a dysfunctional phenotype due to increased expression of inhibitory receptors such as CTLA-4 and PD-1, leading to reduced antitumor activity. Monoclonal antibodies that block these inhibitory signals-collectively known as immune checkpoint inhibitors (ICIs)-can reactivate these T cells, enhancing their ability to target and destroy cancer cells. Recent advancements have highlighted the critical role of T helper subsets in modulating responses to ICIs, with their interactions remaining a focus of ongoing research. Both positive and negative effects of ICIs have been reported in relation to Th cell subsets, with some effects depending on the type of tumor microenvironment. This review summarizes the crucial roles of different T helper cell subsets in tumor immunity and their complex relationship with immune checkpoint inhibitor therapy.

Targeting the tumour cell surface in advanced prostate cancer

Prostate cancer remains a substantial health challenge, with >375,000 annual deaths amongst men worldwide. Most prostate cancer-related deaths are attributable to the development of resistance to standard-of-care treatments. Characterization of the diverse and complex surfaceome of treatment-resistant prostate cancer, combined with advances in drug development that leverage cell-surface proteins to enhance drug delivery or activate the immune system, have provided novel therapeutic opportunities to target advanced prostate cancer. The prostate cancer surfaceome, including proteins such as prostate-specific membrane antigen (PSMA), B7-H3, six transmembrane epithelial antigen of the prostate 1 (STEAP1), delta-like ligand 3 (DLL3), trophoblastic cell-surface antigen 2 (TROP2), prostate stem cell antigen (PSCA), HER3, CD46 and CD36, can be exploited as therapeutic targets, as regulatory mechanisms might contribute to the heterogeneity of expression of these proteins and subsequently affect treatment response and resistance. Specific treatment strategies targeting the surfaceome are in clinical development, including radionuclides, antibody-drug conjugates, T cell engagers and chimeric antigen receptor (CAR) T cells. Ultimately, biomarker development and clinical implementation of these agents will be informed and refined by further understanding of the biology of various targets; the target specificity and sensitivity of different agents; and off-target and toxic effects associated with these agents. Understanding the dynamic nature of cell-surface targets and non-overlapping expression patterns might also lead to future combinational strategies.

Recent developments in myeloid immune modulation in cancer therapy

Myeloid cells play a crucial dual role in cancer progression and response to therapy, promoting tumor growth, enabling immune suppression, and contributing to metastatic spread. The ability of these cells to modulate the immune system has made them attractive targets for therapeutic strategies aimed at shifting their function from tumor promotion to fostering antitumor immunity. Therapeutic approaches targeting myeloid cells focus on modifying their numbers, genetics, metabolism, and interactions within the tumor microenvironment. These strategies aim to reverse their suppressive functions and redirect them to support antitumor immune responses by inhibiting immunosuppressive pathways, targeting specific receptors, and promoting their differentiation into less immunosuppressive phenotypes. Here, we discuss recent approaches to clinically target tumor myeloid cells, focusing on reprogramming myeloid cells to promote antitumor immunity.

Key immune cells and their crosstalk in the tumor microenvironment of bladder cancer: insights for innovative therapies

Bladder cancer (BC) is a heterogeneous disease associated with high mortality if not diagnosed early. BC is classified into non-muscle-invasive BC (NMIBC) and muscle-invasive BC (MIBC), with MIBC linked to poor systemic therapy response and high recurrence rates. Current treatments include transurethral resection with Bacillus Calmette-Guérin (BCG) therapy for NMIBC and radical cystectomy with chemotherapy and/or immunotherapy for MIBC. The tumor microenvironment (TME) plays a critical role in cancer progression, metastasis, and therapeutic efficacy. A comprehensive understanding of the TME's complex interactions holds substantial translational significance for developing innovative treatments. The TME can contribute to therapeutic resistance, particularly in immune checkpoint inhibitor (ICI) therapies, where resistance arises from tumor-intrinsic changes or extrinsic TME factors. Recent advancements in immunotherapy highlight the importance of translational research to address these challenges. Strategies to overcome resistance focus on remodeling the TME to transform immunologically "cold" tumors, which lack immune cell infiltration, into "hot" tumors that respond better to immunotherapy. These strategies involve disrupting cancer-microenvironment interactions, inhibiting angiogenesis, and modulating immune components to enhance anti-tumor responses. Key mechanisms include cytokine involvement [e.g., interleukin-6 (IL-6)], phenotypic alterations in macrophages and natural killer (NK) cells, and the plasticity of cancer-associated fibroblasts (CAFs). Identifying potential therapeutic targets within the TME can improve outcomes for MIBC patients. This review emphasizes the TME's complexity and its impact on guiding novel therapeutic approaches, offering hope for better survival in MIBC.

Intranuclear TCA and mitochondrial overload: The nascent sprout of tumors metabolism

Abnormal glucose metabolism in tumors is a well-known form of metabolic reprogramming in tumor cells, the most representative of which, the Warburg effect, has been widely studied and discussed since its discovery. However, contradictions in a large number of studies and suboptimal efficacy of drugs targeting glycolysis have prompted us to further deepen our understanding of glucose metabolism in tumors. Here, we review recent studies on mitochondrial overload, nuclear localization of metabolizing enzymes, and intranuclear TCA (nTCA) in the context of the anomalies produced by inhibition of the Warburg effect. We provide plausible explanations for many of the contradictory points in the existing studies, including the causes of the Warburg effect. Furthermore, we provide a detailed prospective discussion of these studies in the context of these new findings, providing new ideas for the use of nTCA and mitochondrial overload in tumor therapy.

Histone acetylation modulators in breast cancer

Breast cancer is the most prevalent cancer in women worldwide. Aberrant epigenetic reprogramming such as dysregulation of histone acetylation has been associated with the development of breast cancer. Histone acetylation modulators have been targeted as potential treatments for breast cancer. This review comprehensively discusses the roles of these modulators and the effects of their inhibitors on breast cancer. In addition, epigenetic reprogramming not only affects breast cancer cells but also the immunosuppressive myeloid cells, which can facilitate breast cancer progression. Therefore, the review also highlights the roles of these immunosuppressive myeloid cells and summarizes how histone acetylation modulators affect their functions and phenotypes. This review provides insights into histone acetylation modulators as potential therapeutic targets for breast cancer.

From Bench to Bladder: The Rise in Immune Checkpoint Inhibition in the Treatment of Non-Muscle Invasive Bladder Cancer

Non-muscle invasive bladder cancer (NMIBC) represents a significant clinical challenge due to its high recurrence rate and need for frequent monitoring. The current treatment modality is bacillus Calmette-Guérin (BCG) therapy combined with chemotherapy after transurethral resection of the bladder tumor (TURBT), which is highly effective in most patients. Yet, the cancer becomes resistant to these treatments in 30-40% of patients, necessitating the need for new treatment modalities. In the cancer world, the development of immune checkpoint inhibitors that target molecules, such as programmed cell death protein-1 (PD-1), its ligand, PD-L1, and Cytotoxic T-lymphocyte-associated protein-4 (CTLA-4), have revolutionized the treatment of many cancer types. PD-1/PD-L1 and CTLA-4 are shown to be upregulated in NMIBC in certain circumstances. PD-1/PD-L1 interactions play a role in immune evasion by suppressing T cell activity within the tumor microenvironment (TME), while the binding of CTLA-4 on T cells leads to downregulation of the immune response, making these pathways potential immunotherapeutic targets in NMIBC. This review seeks to understand the role of these therapies in treating NMIBC. We explore the cellular and non-cellular immune landscape in the TME of NMIBC, including Tregs, T effector cells, macrophages, B cells, and relevant cytokines. We also discuss the biological role of PD-1/PD-L1 and CTLA-4 while covering the rationale for these immunotherapies in NMIBC. Finally, we cover key clinical trials that have studied these treatments in NMIBC clinically. Such a study will be helpful for urologists and oncologists to manage patients with NMIBC more effectively.

CDKN2A Low cancer cells outcompete macrophages for microenvironmental zinc to drive immunotherapy resistance

Approximately 50% of cancers exhibit decreased CDKN2A expression ( CDKN2A Low ), which is linked to immune checkpoint blockade (ICB) resistance. While CDKN2A is traditionally recognized as a tumor suppressor and cell cycle regulator, we have previously put forth a new paradigm demonstrating its role in intracellular metabolic reprogramming. Whether the metabolic derangement due to CDKN2A loss alters metabolites within the tumor microenvironment (TME) and how that affects the immune compartment and ICB response has never been investigated. Here we found that CDKN2A Low cancer cells reorganize zinc compartmentalization by upregulating the zinc importer SLC39A9 in the plasma membrane, leading to intracellular zinc accumulation in cancer cells and concurrent zinc depletion in the TME. This competition for zinc results in zinc-starved tumor-associated macrophages (TAMs), leading to reduced phagocytic activity. Increasing zinc in TAMs through multiple approaches, including a dietary intervention that increases availability of TME zinc, re-educates these TAMs to a pro-phagocytic phenotype. Remarkably, both knockdown of Slc39a9 in cancer cells or providing a high zinc diet sensitizes Cdkn2a Low tumors to ICB. TAMs, not T cells, are indispensable for ICB response. Clinically, TAMs from CDKN2A Low cancer patients have decreased zinc signatures, corresponding to reduced phagocytosis signatures. Moreover, patients with low circulating zinc levels have reduced time-to-event outcomes compared to those with higher zinc levels. Our work reveals a previously unrecognized mechanism through which CDKN2A Low cancer cells outcompete TAMs for zinc, directly disrupting their function and ICB efficacy.

Myeloid cells are involved in tumor immunity, metastasis and metabolism in tumor microenvironment

Bone marrow-derived cells in the tumor microenvironment, including macrophages, neutrophils, dendritic cells, myeloid-derived suppressor cells, eosinophils and basophils, participate in the generation, development, invasion and metastasis of tumors by producing different cytokines and interacting with other cell types, and play a pro-tumor or anti-tumor role in regulating tumor immunity. Due to the complexity of cell types in the tumor microenvironment and the unknown process of tumor development and metastasis, cancer treatment to achieve better survival status remains challenging. In this article, we summarize the effects of myeloid cells in tumor microenvironment on tumor immunity, cancer migration, and crosstalk with metabolism (including glucose metabolism, lipid metabolism, and amino acid metabolism), which will help to further study the tumor microenvironment and seek targeted therapeutic strategies for patients.

Tonic signaling in CAR-T therapy: the lever long enough to move the planet

Chimeric antigen receptor (CAR) T-cell therapy has shown remarkable efficacy in treating hematological malignancies and is expanding into other indications such as autoimmune diseases, fibrosis, aging and viral infection. However, clinical challenges persist in treating solid tumors, including physical barriers, tumor heterogeneity, poor in vivo persistence, and T-cell exhaustion, all of which hinder therapeutic efficacy. This review focuses on the critical role of tonic signaling in CAR-T therapy. Tonic signaling is a low-level constitutive signaling occurring in both natural and engineered antigen receptors without antigen stimulation. It plays a pivotal role in regulating immune cell homeostasis, exhaustion, persistence, and effector functions. The "Peak Theory" suggests an optimal level of tonic signaling for CAR-T function: while weak tonic signaling may result in poor proliferation and persistence, excessively strong signaling can cause T cell exhaustion. This review also summarizes the recent progress in mechanisms underlying the tonic signaling and strategies to fine-tune the CAR tonic signaling. By understanding and precisely modulating tonic signaling, the efficacy of CAR-T therapies can be further optimized, offering new avenues for treatment across a broader spectrum of diseases. These findings have implications beyond CAR-T cells, potentially impacting other engineered immune cell therapies such as CAR-NK and CAR-M.

RAW264.7 Macrophages as a Polarization Model in the Context of Pancreatic Cancer and Chemokine Release

The TME is a critical niche for determining the fate of cancer therapy. Tumor cells often polarize nontumor cells, including immune cells, in the TME to favor cancer growth. In pancreatic cancer, macrophages are associated with poor therapy outcomes and unfavorable survival, especially when rendered into M2 macrophages. The latter show features also found in so-called tumor-associated macrophages (TAM), which are described as protecting and propelling tumor growth. In this context, it has been understudied which pancreatic cancer chemokines contribute to macrophage polarization. To this end, we analyzed murine RAW264.7 macrophages and Panc02 and PDA6606 pancreatic cancer cells in mono- and coculture to identify release patterns of 13 chemokines. Artificial macrophage polarization confirmed prominent changes in surface receptor and chemokine secretion profiles. Strikingly, RAW264.7 cocultures with Panc02 or PDA6606 were congruent in showing elevated levels of CCL2, CCL5, CCL17, CCL20, CCL22, CXCL5, and CXCL10. Further underlining the suitability of our in vitro model, both pancreatic cancer cell lines showed similar modulation of the critical macrophage polarization markers arginase, CD206, and iNOS, as well as chemokine receptors CCR2 and CCR4. Collectively, we demonstrated that our model is suitable for testing the roles and functions of chemokines in macrophage polarization by pancreatic cancer cells.

Evaluating the relationship between inflammatory markers and preoperative delirium in elderly hip fracture patients: A retrospective observational study

Preoperative delirium is common and associated with poor clinical outcomes in elderly hip fracture patients. Although inflammatory markers have shown potential in predicting postoperative delirium, their relevance to preoperative delirium remains unclear. This study aimed to investigate the relationship between inflammatory markers and preoperative delirium to improve risk prediction and management strategies. We retrospectively studied 548 elderly hip fracture patients aged 70 years or older. The primary outcome was preoperative delirium diagnosed using the Confusion Assessment Method (CAM). Explanatory variables included inflammatory markers (neutrophil-to-lymphocyte ratio [NLR], platelet-to-lymphocyte ratio [PLR], systemic immune-inflammation index [SII], inflammatory burden index [IBI], and systemic inflammation response index [SIRI]). About 7.66% of patients developed preoperative delirium in the study. These patients were more likely to be older, have comorbid cardiovascular disease, and be transferred to an internal medicine ward for further treatment (P < .001). Multivariate analysis further revealed that older age (OR = 1.11, 95% CI = 1.04-1.18) and comorbid cardiovascular disease (OR = 2.94, 95% CI = 1.51-5.67) were independently associated with the occurrence of preoperative delirium. No significant differences were observed between groups for inflammatory markers: NLR (P = .70), PLR (P = .09), IBI (P = .09), SII (P = .21), or SIRI (P = .80). Older age and cardiovascular comorbidities were independent risk factors for preoperative delirium. No significant associations were found with inflammatory markers. Future research should explore additional biomarkers to refine risk stratification in this population.

A One Stone Three Birds Paradigm of Photon-Driven Pyroptosis Dye for Amplifying Tumor Immunotherapy

Activating the pyroptosis pathway of tumor cells by photodynamic therapy (PDT) for immunogenic cell death (ICD) is considered a valid strategy in pursuit of antitumor immunotherapy, but it remains a huge challenge due to the lack of reliable design guidelines. Moreover, it is often overlooked that conventional PDT can exacerbate the development of tumor immunosuppressive microenvironment, which is apparently unfavorable to clinical immunotherapy. The endoplasmic reticulum's (ER) pivotal role in cellular homeostasis and its emerging link to pyroptosis have galvanized interest in ER-centric imaging and therapeutics. Herein, using the targeted group-assisted strategy (TAGS), an intriguing cyclooxygenase-2-targeted photodynamic conjugate, Indo-Cy, strategically created, which exploits the enzyme's overabundance in the tumoral ER, especially under proinflammatory hypoxic conditions. This conjugate, with its highly precise ER imaging, embodies a trifunctional strategy: i) innovating an electron transfer mechanism, converting the hemicyanine moiety into an oxygen-independent type I photosensitizer, thereby navigating around the hypoxia constraints of traditional PDT; ii) executing precise ER-targeted PDT, amplifying caspase-1/GSDMD-mediated pyroptosis for ICD; 3) attenuating immunosuppressive pathways by inhibiting cyclooxygenase-2 downstream factors, including HIF-1α, PGE2, and VEGF. Indo-Cy's multimodal approach potently induces in vivo tumor pyroptosis and bolsters antitumor immunity, underscoring cyclooxygenase-2-targeted dyes' potential as a versatile oncotherapeutics.

Myeloid-derived suppressor cell inhibits T-cell-based defense against Klebsiella pneumoniae infection via IDO1 production

Klebsiella pneumoniae (Kp) is responsible for a wide range of infections, including pneumonia, sepsis, and urinary tract infections. However, the treatment options are limited due to the continuous evolution of drug-resistant and hypervirulent variants. It is crucial to investigate the mechanisms behind the high mortality rate of hypervirulent Kp (hvKp) strains to develop new strategies for preventing hvKp from evading the host's defenses and improving treatment effectiveness for these fatal infections. In this study, we used a hvKp-induced mouse bacteremia model and performed single-cell RNA sequencing to investigate the effects of hvKp infection. Our findings demonstrated that hvKp infection led to a decrease in lymphocytes (lymphopenia), attributed to impaired proliferation and apoptosis. The infiltration of myeloid-derived suppressor cells (MDSCs) in the infected lungs was confirmed to suppress T cell proliferation, leading to lymphopenia. We further identified that hvKp promotes tryptophan metabolism in infected lungs, enhancing the immunosuppressive activity of MDSCs by inducing the production of the enzyme IDO1. Our ex vivo inhibition experiment revealed that L-kynurenine, a product of tryptophan metabolism, inhibits T-cell proliferation and induces T-cell apoptosis, further suppressing T-cell mediated responses against bacteria. Importantly, when we knocked out the Ido1 gene or inhibited IDO1 expression using a specific inhibitor 1-MT in mice, we observed a significant enhancement in T-cell mediated responses against hvKp. These findings highlight the crucial role of MDSCs in hvKp-induced bacteremia and suggest a promising immunotherapeutic approach by inhibiting IDO1 production to combat infectious diseases.

The multifaceted roles of macrophages in the transition from hepatitis to hepatocellular carcinoma: From mechanisms to therapeutic strategies

Macrophages are central to the progression from hepatitis to hepatocellular carcinoma (HCC), with their remarkable plasticity and ability to adapt to the changing liver microenvironment. Chronic inflammation, fibrosis, and ultimately tumorigenesis are driven by macrophage activation, making them key regulators of liver disease progression. This review explores the diverse roles of macrophages in the transition from hepatitis to HCC. In the early stages of hepatitis, macrophages are essential for pathogen clearance and tissue repair. However, chronic activation leads to prolonged inflammation, which exacerbates liver damage and promotes fibrosis. As the disease progresses to liver fibrosis, macrophages interact with hepatic stellate cells, fostering a pro-tumorigenic microenvironment that supports HCC development. In hepatocarcinogenesis, macrophages contribute to tumor initiation, growth, metastasis, immune evasion, cancer stem cell maintenance, and angiogenesis. Their functional plasticity enables them to adapt to the tumor microenvironment, thereby promoting tumor progression and resistance to therapy. Targeting macrophages represents a promising strategy for preventing and treating HCC. Therapeutic approaches, including reprogramming macrophage phenotypes to enhance anti-tumor immunity, blocking macrophage recruitment and activation, and utilizing nanoparticle-based drug delivery systems, may provide new avenues for combating HCC by modulating macrophage functions and tumor microenvironment dynamics.

Timp2 loss-of-function mutation and TIMP2 treatment in a murine model of NSCLC: Modulation of immunosuppression and oncogenic signaling

Mounting evidence suggests that the tissue inhibitor of metalloproteinases-2 (TIMP2) can reduce tumor burden and metastasis. However, the demonstration of such anti-tumor activity and associated mechanisms using in vivo tumor models is lacking. The effects of a Timp2 functional mutation and administration of recombinant TIMP2 were examined in both orthotopic and heterotopic murine models of lung cancer using C57Bl/6 syngeneic Lewis Lung 2-luciferase 2 cells (LL2-Luc2) cells. Mice harboring a functional mutation of TIMP2 (mT2) display markedly increased primary lung tumor growth, increased mortality, enriched vasculature, and enhanced infiltration of pro-tumorigenic, immunosuppressive myeloid cells. Treatment with recombinant TIMP2 reduced primary tumor growth in both mutant and wild-type (wt) mice. Comparison of transcriptional profiles of lung tissues from tumor-free, wt versus mT2 mice reveals only minor changes. However, lung tumor-bearing mice of both genotypes demonstrate significant genotype-dependent changes in gene expression following treatment with TIMP. In tumor-bearing wt mice, TIMP2 treatment reduced the expression of upstream oncogenic mediators, whereas treatment of mT2 mice resulted in an immunomodulatory phenotype. A heterotopic subcutaneous model generating metastatic pulmonary tumors demonstrated that daily administration of recombinant TIMP2 significantly reduces the expression of heat shock proteins, suggesting a reduction of cell-stress responses. In summary, we describe how TIMP2 exerts novel, anti-tumor effects in a murine model of lung cancer and that rTIMP2 treatment supports a normalizing effect on the tumor microenvironment. Our findings show that TIMP2 treatment demonstrates significant potential as an adjuvant in the treatment of NSCLC.

Antitumor host immunity enhanced by near-infrared photoimmunotherapy

Near-infrared photoimmunotherapy (NIR-PIT) is a novel antitumor therapy that selectively kills cancer cells by NIR light-triggered photochemical reaction of IRDye700DX within Ab-photoabsorber conjugates (APCs). NIR-PIT induces immunogenic cell death, causing immune cell migration between the tumor and tumor-draining lymph nodes, and expanding multiclonal tumor-infiltrating CD8+ T cells. Crucially, the cytotoxic effects of NIR-PIT are limited to cancer cells, sparing immune cells such as antigen-presenting cells and T cells, which are key players in boosting antitumor host immunity. By modifying the Ab used in APC synthesis, NIR-PIT can be repurposed to target and deplete noncancerous immunosuppressive cells including regulatory T cells, myeloid-derived suppressor cells, and cancer-associated fibroblasts in the tumor microenvironment. Immunosuppressive cell targeted NIR-PIT strongly potentiates antitumor host immunity, including the induction of abscopal effects and the development of immune memory. Furthermore, antitumor immune responses and therapeutic efficacy are synergistically enhanced when NIR-PIT is combined with other immune-activating treatments, such as interleukin-15 and immune checkpoint inhibitors. These new findings make NIR-PIT a valuable tool in the evolving landscape of cancer immunotherapy. This review explains the role of NIR-PIT in activating antitumor host immunity.

The lactate receptor HCAR1 drives the recruitment of immunosuppressive PMN-MDSCs in colorectal cancer

Most patients with colorectal cancer do not achieve durable clinical benefits from immunotherapy, underscoring the existence of alternative immunosuppressive mechanisms. Here we found that activation of the lactate receptor HCAR1 signaling pathway induced the expression of chemokines CCL2 and CCL7 in colorectal tumor cells, leading to the recruitment of immunosuppressive CCR2+ polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) to the tumor microenvironment. Ablation of Hcar1 in mice with colorectal tumors significantly decreased the abundance of tumor-infiltrating CCR2+ PMN-MDSCs, enhanced the activation of CD8+ T cells and, consequently, reduced tumor burden. We detected immunosuppressive CCR2+ PMN-MDSCs in tumor specimens from individuals with colorectal and other cancers. The US Food and Drug Administration-approved drug reserpine suppressed lactate-mediated HCAR1 activation, impaired the recruitment of CCR2+ PMN-MDSCs, boosted CD8+ T cell-dependent antitumor immunity and sensitized immunotherapy-resistant tumors to programmed cell death protein 1 antibody therapy in mice with colorectal tumors. Altogether, we described HCAR1-driven recruitment of CCR2+ PMN-MDSCs as a mechanism of immunosuppression.

Targeting myeloid-derived suppressor cells in the tumor microenvironment: potential therapeutic approaches for osteosarcoma

Osteosarcoma is a bone malignancy characterized by strong invasiveness and rapid disease progression. The tumor microenvironment of osteosarcoma contains various types of immune cells, including myeloid-derived suppressor cells, macrophages, T cells, and B cells. Imbalances of these immune cells can promote the proliferation and metastasis of osteosarcoma. Recent studies have indicated a substantial increase in the levels of myeloid-derived suppressor cells, an immune cell associated with immunosuppressive and pro-cancer effects, in the peripheral blood of patients with osteosarcoma. Moreover, the levels of the pro-inflammatory cytokine interleukin 18 are positively correlated with those of myeloid-derived suppressor cells in the peripheral blood of animal models of osteosarcoma. In this review, we explore the function of myeloid-derived suppressor cells in osteosarcoma based on the clinical diagnoses of patients with osteosarcoma and discuss future therapeutic approaches for targeting osteosarcoma. Targeting myeloid-derived suppressor cells represents a promising approach to improving the prognosis and survival rates of patients with osteosarcoma.

Roux-en-Y gastric bypass-associated fecal tyramine promotes colon cancer risk via increased DNA damage, cell proliferation, and inflammation

BACKGROUND

Fecal abundances of Enterobacteriaceae and Enterococcaceae are elevated in patients following Roux-en-Y gastric bypass (RYGB) surgery. Concurrently, fecal concentrations of tyramine, derived from gut bacterial metabolism of tyrosine and/or food, increased post-RYGB. Furthermore, emerging evidence suggests that RYGB is associated with increased colorectal cancer (CRC) risk. However, the causal link between RYGB-associated microbial metabolites and CRC risk remains unclear. Hence, this study investigated the tyrosine metabolism of Enterobacteriaceae and Enterococcaceae strains isolated from patients post-RYGB and explored the causal effects of tyramine on the CRC risk and tumorigenesis using both human colonic cancer cell line (HCT 116) and wild-type and ApcMin/+ mice.

RESULTS

We isolated 31 bacterial isolates belonging to Enterobacteriaceae and Enterococcaceae families from the feces of patients with RYGB surgery. By culturing the isolates in tyrosine-supplemented medium, we found that Citrobacter produced phenol as a main product of tyrosine, whereas Enterobacter and Klebsiella produced 4-hydroxyphenylacetate, Escherichia produced 4-hydroxyphenyllactate and 4-hydroxyphenylpyruvate, and Enterococcus and two Klebsiella isolates produced tyramine. These observations suggested the gut bacterial contribution to increased fecal concentrations of tyramine post-RYGB. We subsequently evaluated the impact of tyramine on CRC risk and development. Tyramine induced necrosis and promoted cell proliferation and DNA damage of HCT 116 cells. Daily oral administration of tyramine for 49 days to wild-type mice resulted in visible adenomas in 5 out of 12 mice, accompanied by significantly enhanced DNA damage (γH2AX +) and an increased trend of cell proliferation (Ki67 +) in the ileum, along with an upregulated expression of the cell division cycle gene (Cdc34b) in the colon. To evaluate the impact of tyramine on intestinal tumor growth, we treated ApcMin/+ mice with the same doses of tyramine and duration. These mice showed larger colonic tumor size and increased intestinal cell proliferation and inflammation (e.g., increased mRNA expression of IL-17A and higher number of Ly6G + neutrophils) compared to water-treated ApcMin/+ control mice.

CONCLUSIONS

Our results collectively suggested that RYGB-associated fecal bacteria could contribute to tyramine production and tyramine increased CRC risk by increasing DNA damage, cell proliferation, and pro-inflammatory responses of the gut. Monitoring and modulating tyramine concentrations in high-risk individuals could aid CRC prognosis and management. Video Abstract.

Peripheral blood proteome biomarkers distinguish immunosuppressive features of cancer progression

Immune status critically affects cancer progression and therapy responses. This study aimed to identify plasma proteome changes in immunosuppressive cancer and potential biomarkers predicting systemic immunosuppression. Mouse models of syngeneic breast tumors (benign 67NR and malignant 4T1) were used to collect plasma samples. Plasma samples from naive mice and both early- and late-stage tumor-bearing mice were subjected to liquid chromatography-mass spectrometry (LC-MS) analysis. 4T1-bearing mice showed systemic immunosuppression characterized by significant generation of myeloid-derived suppressor cells (MDSCs) as early as 7 days after tumor implantation, unlike 67NR tumors. LC-MS identified 1086 proteins across the five experimental groups, with 27 proteins showing group-specific expression in 4T1 blood compared with 67NR blood. Immune-related proteins osteopontin, lactotransferrin, calreticulin, and peroxiredoxin 2 were selected as potential biomarkers of MDSC-producing breast cancer. These markers were expressed in cancer cells or MDSC in the 4T1 model, and osteopontin and peroxiredoxin 2 were associated with low survival probability and high recurrence in patients with triple-negative breast cancer. Our findings suggest that MDSC-producing immunosuppressive cancers have unique plasma proteomes, offering additional insights into cancer immune status.

Coactivation of innate immune suppressive cells induces acquired resistance against combined TLR agonism and PD-1 blockade

Immune checkpoint blockade therapy has been successfully applied in clinical settings as a standard therapy for many cancer types, but its clinical efficacy is restricted to patients with immunologically hot tumors. Various strategies to modify the tumor microenvironment (TME), such as Toll-like receptor (TLR) agonists that can stimulate innate immunity, have been explored but have not been successful. Here, we show a mechanism of acquired resistance to combination treatment consisting of an agonist for multiple TLRs, OK-432 (Picibanil), and programmed cell death protein 1 (PD-1) blockade. Adding the TLR agonist failed to convert the TME from immunogenically cold to hot and did not augment antitumor immunity, particularly CD8+ T cell responses, in multiple animal models. The failure was attributed to the coactivation of innate suppressive cells, such as polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) expressing CXCR2, through high CXCL1 production by macrophages in the TME upon OK-432 treatment. A triple combination treatment with OK-432, PD-1 blockade, and a CXCR2 neutralizing antibody overcame the resistance induced by PMN-MDSCs, resulting in a stronger antitumor effect than that of any dual combinations or single treatments. The accumulation of PMN-MDSCs was similarly observed in the pleural effusions of patients with lung cancer after OK-432 administration. We propose that successful combination cancer immunotherapy intended to stimulate innate antitumor immunity requires modulation of unwanted activation of innate immune suppressive cells, including PMN-MDSCs.

Machine learning model using immune indicators to predict outcomes in early liver cancer

BACKGROUND

Patients with early-stage hepatocellular carcinoma (HCC) generally have good survival rates following surgical resection. However, a subset of these patients experience recurrence within five years post-surgery.

AIM

To develop predictive models utilizing machine learning (ML) methods to detect early-stage patients at a high risk of mortality.

METHODS

Eight hundred and eight patients with HCC at Beijing Ditan Hospital were randomly allocated to training and validation cohorts in a 2:1 ratio. Prognostic models were generated using random survival forests and artificial neural networks (ANNs). These ML models were compared with other classic HCC scoring systems. A decision-tree model was established to validate the contribution of immune-inflammatory indicators to the long-term outlook of patients with early-stage HCC.

RESULTS

Immune-inflammatory markers, albumin-bilirubin scores, alpha-fetoprotein, tumor size, and International Normalized Ratio were closely associated with the 5-year survival rates. Among various predictive models, the ANN model generated using these indicators through ML algorithms exhibited superior performance, with a 5-year area under the curve (AUC) of 0.85 (95%CI: 0.82-0.88). In the validation cohort, the 5-year AUC was 0.82 (95%CI: 0.74-0.85). According to the ANN model, patients were classified into high-risk and low-risk groups, with an overall survival hazard ratio of 7.98 (95%CI: 5.85-10.93, P < 0.0001) between the two cohorts.

CONCLUSION

A non-invasive, cost-effective ML-based model was developed to assist clinicians in identifying high-risk early-stage HCC patients with poor postoperative prognosis following surgical resection.

H3.3-G34R Mutation-Mediated Epigenetic Reprogramming Leads to Enhanced Efficacy of Immune Stimulatory Gene Therapy in Diffuse Hemispheric Gliomas

Diffuse hemispheric glioma (DHG), H3 G34-mutant, representing 9-15% of cases, are aggressive Central Nervous System (CNS) tumors with poor prognosis. This study examines the role of epigenetic reprogramming of the immune microenvironment and the response to immune-mediated therapies in G34-mutant DHG. To this end, we utilized human G34-mutant DHG biopsies, primary G34-mutant DHG cultures, and genetically engineered G34-mutant mouse models (GEMMs). Our findings show that the G34 mutation alters histone marks' deposition at promoter and enhancer regions, leading to the activation of the JAK/STAT pathway, which in turn results in an immune-permissive tumor microenvironment. The implementation of Ad-TK/Ad-Flt3L immunostimulatory gene therapy significantly improved median survival, and lead to over 50% long term survivors. Upon tumor rechallenge in the contralateral hemisphere without any additional treatment, the long-term survivors exhibited robust anti-tumor immunity and immunological memory. These results indicate that immune-mediated therapies hold significant potential for clinical translation in treating patients harboring H3.3-G34 mutant DHGs, offering a promising strategy for improving outcomes in this challenging cancer subtype affecting adolescents and young adults (AYA).

STATEMENT OF SIGNIFICANCE

This study uncovers the role of the H3.3-G34 mutation in reprogramming the tumor immune microenvironment in diffuse hemispheric gliomas. Our findings support the implementation of precision medicine informed immunotherapies, aiming at improving enhanced therapeutic outcomes in adolescents and young adults harboring H3.3-G34 mutant DHGs.

Therapeutic targeting of cGAS-STING pathway in lung cancer

The presence of DNA in the cytosol triggers a protective response from the innate immune system. Cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) is an essential cytosolic DNA sensor that triggers a potent innate immune response. As a result of this signaling cascade reaction, type I interferon and other immune mediators activate an immune response. The cGAS-STING pathway has great anticancer immunity-boosting potential since it produces type I interferons. The detection of double-stranded DNA (dsDNA) in response to various stimuli initiates a protective host's cGAS-STING signals. So, it is clear that a substantial relationship is expected between cancer biotherapy and the functioning of the cGAS-STING pathway. Several STING agonists with promising outcomes have been created for preclinical cancer therapy research. Notably, immunotherapy has dramatically extended patient survival and radically altered the course of lung cancer treatment, particularly in more advanced instances. However, this method is still ineffective for a large number of lung cancer patients. cGAS-STING can overcome resistance and boost anticancer immunity by stimulating the activity of many pro-inflammatory mediators, augmenting dendritic cell cross-presentation, and initiating a tumor-specific CD8+ T cell response. This review aims to present the most recent results on the functionality of the cGAS-STING pathway in cancer progression and its potential as an immunotherapy target, with a focus on lung cancer.

CXCL16/CXCR6/TGF-β Feedback Loop Between M-MDSCs and Treg Inhibits Anti-Bacterial Immunity During Biofilm Infection

Staphylococcus aureus (S. aureus) is a leading cause of Periprosthetic  joint  infection (PJI), a severe complication after joint arthroplasty. Immunosuppression is a major factor contributing to the infection chronicity of S. aureus PJI, posing significant treatment challenges. This study investigates the relationship between the immunosuppressive biofilm milieu and S. aureus PJI outcomes in both discovery and validation cohorts. This scRNA-seq analysis of synovium from PJI patients reveals an expansion and heightened activity of monocyte-related myeloid-derived suppressor cells (M-MDSCs) and regulatory T cells (Treg). Importantly, CXCL16 is significantly upregulated in M-MDSCs, with its corresponding CXCR6 receptor also elevated on Treg. M-MDSCs recruit Treg and enhance its activity via CXCL16-CXCR6 interactions, while Treg secretes TGF-β, inducing M-MDSCs proliferation and immunosuppressive activity. Interfering with this cross-talk in vivo using Treg-specific CXCR6 knockout PJI mouse model reduces M-MDSCs/Treg-mediated immunosuppression and alleviates bacterial burden. Immunohistochemistry and recurrence analysis show that PJI patients with CXCR6high synovium have poor prognosis. This findings highlight the critical role of CXCR6 in Treg in orchestrating an immunosuppressive microenvironment and biofilm persistence during PJI, offering potential targets for therapeutic intervention.

Rbfox3 Promotes Transformation of MDSC-Like Tumor Cells to Shape Immunosuppressive Microenvironment

Myeloid-derived suppressor cells (MDSCs) within the tumor microenvironment (TME) contribute to the malignant progression of tumors by exerting immunosuppressive effects. Bacterial lipopolysaccharides (LPS) have been widely demonstrated in various types of solid tumors. LPS can promote the malignant progression of tumors, which mechanism has not yet been fully elucidated. In this study, a type of MDSC-like tumor cells (MLTCs) is found in tumor tissues induced by low-dose and long-term LPS stimulation. MLTCs can simultaneously express tumor cell and MDSCs markers. Similar to MDSCs, MLTCs can produce arginine, nitric oxide, and reactive oxygen species and inhibit the activity of NK and T cells to promote the formation of an immunosuppressive microenvironment. MLTCs can also promote tumor cell proliferation and vasculogenic mimicry formation. CRISPR-Cas9 activity screening studies identified RNA-binding Fox-1 homolog 3 (Rbfox3) as a critical protein for MLTCs formation after LPS treatment. Rbfox3 can transcriptionally regulate the expression of Ass1 in the form of phase-separated particles. Crocin can inhibit the generation of MLTCs by disrupting phase-separated particles of Rbfox3 and enhance the anti-tumor effects of immune checkpoint inhibitors (ICIs).

Trained immunity in chronic inflammatory diseases and cancer

A decade after the term 'trained immunity' (TRIM) was coined to reflect the long-lasting hyper-responsiveness of innate immune cells with an epigenetically imprinted 'memory' of earlier stimuli, our understanding has broadened to include the potential implications of TRIM in health and disease. Here, after summarizing the well-documented beneficial effects of TRIM against infections, we discuss emerging evidence that TRIM is also a major underlying mechanism in chronic inflammation-related disorders such as periodontitis, rheumatoid arthritis and cardiovascular disease. Furthermore, mounting evidence indicates that the induction of TRIM by certain agonists confers protective antitumour responses. Although the mechanisms underlying TRIM require further study, the current knowledge enables the experimental development of innovative therapeutic approaches to stimulate or inhibit TRIM in a context-appropriate manner, such as the stimulation of TRIM in cancer or its inhibition in inflammatory disorders.

Adaptive Immunity Determines the Cancer Treatment Outcome of Oncolytic Virus and Anti-PD-1

The immune checkpoint inhibitor, anti-programmed death protein-1 (anti-PD-1), enhances adaptive immunity to kill tumor cells, and the oncolytic virus (OV) triggers innate immunity to clear the infected tumor cells. We create a mathematical model to investigate how the interaction between adaptive and innate immunities under OV and anti-PD-1 affects tumor reduction. For different immunity strength, we create the corresponding virtual baseline patients and cohort patients to decipher the major factors determining the treatment outcome. Global sensitivity analysis indicates that adaptive immunity has more control on the treatment outcome than innate immunity, and whether anti-PD-1 cancels out the OV treatment efficacy depends on the OV dosage and the balance between clearance of infected tumor cells and OV by T cells. The optimal OV infection rate and dosage suggest that OV treatment is more sensitive to adaptive immunity than innate immunity. Our model prediction also indicates that tumor reduction is more sensitive to anti-PD-1 efficacy as adaptive immunity becomes stronger, and anti-PD-1 trends to cancel out the OV treatment efficacy as innate immunity becomes stronger. Based on these results, the recommended treatment protocol for patients with different immunity strength can be determined.

Targeting HGF/c-MET signaling to regulate the tumor microenvironment: Implications for counteracting tumor immune evasion

The hepatocyte growth factor (HGF) along with its receptor (c-MET) are crucial in preserving standard cellular physiological activities, and imbalances in the c-MET signaling pathway can lead to the development and advancement of tumors. It has been extensively demonstrated that immune checkpoint inhibitors (ICIs) can result in prolonged remission in certain patients. Nevertheless, numerous preclinical studies have shown that MET imbalance hinders the effectiveness of anti-PD-1/PD-L1 treatments through various mechanisms. Consequently, clarifying the link between the c-MET signaling pathway and the tumor microenvironment (TME), as well as uncovering the effects of anti-MET treatment on ICI therapy, is crucial for enhancing the outlook for tumor patients. In this review, we examine the impact of abnormal activation of the HGF/c-MET signaling pathway on the control of the TME and the processes governing PD-L1 expression in cancer cells. The review thoroughly examines both clinical and practical evidence regarding the use of c-MET inhibitors alongside PD-1/PD-L1 inhibitors, emphasizing that focusing on c-MET with immunotherapy enhances the effectiveness of treating MET tumors exhibiting elevated PD-L1 expression.