Myeloid-derived suppressor cells-new and exciting players in lung cancer

Application of spatial omics in gastric cancer

Gastric cancer (GC), a globally prevalent and lethal malignancy, continues to be a key research focus. However, due to its considerable heterogeneity and complex pathogenesis, the treatment and diagnosis of gastric cancer still face significant challenges. With the rapid development of spatial omics technology, which provides insights into the spatial information within tumor tissues, it has emerged as a significant tool in gastric cancer research. This technology affords new insights into the pathology and molecular biology of gastric cancer for scientists. This review discusses recent advances in spatial omics technology for gastric cancer research, highlighting its applications in the tumor microenvironment (TME), tumor heterogeneity, tumor genesis and development mechanisms, and the identification of potential biomarkers and therapeutic targets. Moreover, this article highlights spatial omics' potential in precision medicine and summarizes existing challenges and future directions. It anticipates spatial omics' continuing impact on gastric cancer research, aiming to improve diagnostic and therapeutic approaches for patients. With this review, we aim to offer a comprehensive overview to scientists and clinicians in gastric cancer research, motivating further exploration and utilization of spatial omics technology. Our goal is to improve patient outcomes, including survival rates and quality of life.

Myeloid-derived suppressor cells: Implication in myeloid malignancies and immunotherapy

Myeloid malignancies stem from a modified hematopoietic stem cell and predominantly include acute myeloid leukemia, myelodysplastic neoplasms, myeloproliferative malignancies, and chronic myelomonocytic leukemia. Myeloid-derived suppressor cells (MDSCs) exhibit immunoregulatory properties by governing the innate and adaptive immune systems, creating a permissive and supportive environment for neoplasm growth. This review examines the key characteristics of MDSCs in myeloid malignancies, highlighting that an increased MDSC count corresponds to heightened immunosuppressive capabilities, fostering an immune-tolerant neoplasm microenvironment. Also, this review analyzes and describes the potential of combined cancer therapies, focusing on targeting MDSC generation, expansion, and their inherent immunosuppressive activities to enhance the efficacy of current cancer immunotherapies. A comprehensive understanding of the implications of myeloid malignancies may enhance the exploration of immunotherapeutic strategies for their potential application.

Myeloid-derived suppressor cells in cancer: Current knowledge and future perspectives

MDSCs (myeloid-derived suppressor cells) are crucial for immune system evasion in cancer. They accumulate in peripheral blood and tumor microenvironment, suppressing immune cells like T-cells, natural killer cells and dendritic cells. They promote tumor angiogenesis and metastasis by secreting cytokines and growth factors and contribute to a tumor-promoting environment. The accumulation of MDSCs in cancer patients has been linked to poor prognosis and resistance to various cancer therapies. Targeting MDSCs and their immunosuppressive mechanisms may improve treatment outcomes and enhance immune surveillance by developing drugs that inhibit MDSC function, by preventing their accumulation and by disrupting the tumor-promoting environment. This review presents a detailed overview of the MDSC research in cancer with regulation of their development and function. The relevance of MDSC as a prognostic and predictive biomarker in different types of cancers, along with recent advancements on the therapeutic approaches to target MDSCs are discussed in detail.

Myeloid‑derived suppressor cells as targets of emerging therapies and nanotherapies (Review)

Breast cancer (BC) is the leading cause of cancer-related mortality among women worldwide. Immunotherapies are a promising approach in cancer treatment, particularly for aggressive forms of BC with high mortality rates. However, the current eligibility for immunotherapy remains limited to a limited fraction of patients with BC. Myeloid-derived suppressor cells (MDSCs), originating from myeloid cells, are known for their dual role in immunosuppression and tumor promotion, significantly affecting patient outcomes by fostering the formation of premetastatic niches. Consequently, targeting MDSCs has emerged as a promising avenue for further exploration in therapeutic interventions. Leveraging nanotechnology-based drug delivery systems, which excel in accumulating drugs within tumors via passive or active targeting mechanisms, are a promising strategy for the use of MDSCs in the treatment of BC. The present review discusses the immunosuppressive functions of MDSCs, their role in BC, and the diverse strategies for targeting them in cancer therapy. Additionally, the present review discusses future advancements in BC treatments focusing on MDSCs. Furthermore, it elucidates the mechanisms underlying MDSC activation, recruitment and differentiation in BC progression, highlighting the clinical characteristics that render MDSCs suitable candidates for the therapy and targeted nanotherapy of BC.

Myeloid‑derived suppressor cells: Key immunosuppressive regulators and therapeutic targets in colorectal cancer (Review)

Globally, colorectal cancer (CRC) is the third most common type of cancer. CRC has no apparent symptoms in the early stages of disease, and most patients receive a confirmed diagnosis in the middle or late disease stages. The incidence of CRC continues to increase, and the affected population tends to be younger. Therefore, determining how to achieve an early CRC diagnosis and treatment has become a top priority for prolonging patient survival. Myeloid‑derived suppressor cells (MDSCs) are a group of bone marrow‑derived immuno‑negative regulatory cells that are divided into two subpopulations, polymorphonuclear‑MDSCs and monocytic‑MDSCs, based on their phenotypic similarities to neutrophils and monocytes, respectively. These cells can inhibit the immune response and promote cancer cell metastasis in the tumour microenvironment (TME). A large aggregation of MDSCs in the TME is often a marker of cancer and a poor prognosis in inflammatory diseases of the intestine (such as colonic adenoma and ulcerative colitis). In the present review, the phenotypic classification of MDSCs in the CRC microenvironment are first discussed. Then, the amplification, role and metastatic mechanism of MDSCs in the CRC TME are described, focusing on genes, gene modifications, proteins and the intestinal microenvironment. Finally, the progress in CRC‑targeted therapies that aim to modulate the quantity, function and structure of MDSCs are summarized in the hope of identifying potential screening markers for CRC and improving CRC prognosis and therapeutic options.

Turning Waste into Wealth: A Potent Sono-Immune Strategy Based on Microcystis

Currently, sonodynamic therapy (SDT) has limited therapeutic outcomes and immune responses, highlighting the urgent need for enhanced strategies that can stimulate robust and long-lasting antitumor effects. Microcystis, a notorious microalga, reveals the possibility of mediating SDT owing to the presence of gas vesicles (GVs) and phycocyanin (PC). Herein, a nontoxic strain of Microcystis elabens (labeled Me) is developed as a novel agent for SDT because it generates O2 under red light (RL) illumination, while GVs and PC act as cavitation nuclei and sonosensitizers, respectively. Moreover, algal debris is released after ultrasound (US) irradiation, which primes the Toll-like receptor pathway to initiate a cascade of immune responses. This sono-immune strategy inhibits CT26 colon tumor growth largely by promoting dendritic cell (DC) maturation and cytotoxic T-cell activation. After combination with the immune checkpoint blockade (ICB), the therapeutic outcome is further amplified, accompanied by satisfactory abscopal and immune memory effects; the similar potency is proven in the "cold" 4T1 triple-negative breast tumor. In addition, Me exhibits good biosafety without significant acute or chronic toxicity. Briefly, this study turns waste into wealth by introducing sono-immunotherapy based on Microcystis that achieved encouraging therapeutic effects on cancer, which is expected to be translated into the clinic.

Impact of obesity‑associated myeloid‑derived suppressor cells on cancer risk and progression (Review)

Obesity is a chronic disease caused by the accumulation of excessive adipose tissue. This disorder is characterized by chronic low‑grade inflammation, which promotes the release of proinflammatory mediators, including cytokines, chemokines and leptin. Simultaneously, chronic inflammation can predispose to cancer development, progression and metastasis. Proinflammatory molecules are involved in the recruitment of specific cell populations in the tumor microenvironment. These cell populations include myeloid‑derived suppressor cells (MDSCs), a heterogeneous, immature myeloid population with immunosuppressive abilities. Obesity‑associated MDSCs have been linked with tumor dissemination, progression and poor clinical outcomes. A comprehensive literature review was conducted to assess the impact of obesity‑associated MDSCs on cancer in both preclinical models and oncological patients with obesity. A secondary objective was to examine the key role that leptin, the most important proinflammatory mediator released by adipocytes, plays in MDSC‑driven immunosuppression Finally, an overview is provided of the different therapeutic approaches available to target MDSCs in the context of obesity‑related cancer.

G protein-coupled receptor-mediated signaling of immunomodulation in tumor progression

G protein-coupled receptors (GPCRs) are essential contributors to tumor growth and metastasis due to their roles in immune cell regulation. Therefore, GPCRs are potential targets for cancer immunotherapy. Here, we discuss the current understanding of the roles of GPCRs and their signaling pathways in tumor progression from an immunocellular perspective. Additionally, we focus on the roles of GPCRs in regulating immune checkpoint proteins involved in immune evasion. Finally, we review the progress of clinical trials of GPCR-targeted drugs for cancer treatment, which may be combined with immunotherapy to improve treatment efficacy. This expanded understanding of the role of GPCRs may shed light on the mechanisms underlying tumor progression and provide a novel perspective on cancer immunotherapy.

The Multifaceted Role of Neutrophils in NSCLC in the Era of Immune Checkpoint Inhibitors

Lung cancer is the most common cause of cancer-related death in both males and females in the U.S. and non-small-cell lung cancer (NSCLC) accounts for 85%. Although the use of first- or second-line immune checkpoint inhibitors (ICIs) exhibits remarkable clinical benefits, resistance to ICIs develops over time and dampens the efficacy of ICIs in patients. Tumor-associated neutrophils (TANs) have an important role in modulating the tumor microenvironment (TME) and tumor immune response. The major challenge in the field is to characterize the TANs in NSCLC TME and understand the link between TAN-related immunosuppression with ICI treatment response. In this review, we summarize the current studies of neutrophil interaction with malignant cells, T-cells, and other components in the TME. Ongoing clinical trials are aimed at utilizing reagents that have putative effects on tumor-associated neutrophils, in combination with ICI. Elevated neutrophil populations and neutrophil-associated factors could be potential therapeutic targets to enhance anti-PD1 treatment in NSCLC.

A review concerning the breast cancer-related tumour microenvironment

Breast cancer (BC) is currently the most common malignant tumour in women and one of the leading causes of their death around the world. New and increasingly personalised diagnostic and therapeutic tools have been introduced over the last few decades, along with significant advances regarding the study and knowledge related to BC. The tumour microenvironment (TME) refers to the tumour cell-associated cellular and molecular environment which can influence conditions affecting tumour development and progression. The TME is composed of immune cells, stromal cells, extracellular matrix (ECM) and signalling molecules secreted by these different cell types. Ever deeper understanding of TME composition changes during tumour development and progression will enable new and more innovative therapeutic strategies to become developed for targeting tumours during specific stages of its evolution. This review summarises the role of BC-related TME components and their influence on tumour progression and the development of resistance to therapy. In addition, an account on the modifications in BC-related TME components associated with therapy is given, and the completed or ongoing clinical trials related to this topic are presented.

Dual roles of myeloid-derived suppressor cells in various diseases: a review

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of cells that originate from bone marrow stem cells. In pathological conditions, such as autoimmune disorders, allergies, infections, and cancer, normal myelopoiesis is altered to facilitate the formation of MDSCs. MDSCs were first shown to promote cancer initiation and progression by immunosuppression with the assistance of various chemokines and cytokines. Recently, various studies have demonstrated that MDSCs play two distinct roles depending on the physiological and pathological conditions. MDSCs have protective roles in autoimmune disorders (such as uveoretinitis, multiple sclerosis, rheumatoid arthritis, ankylosing spondylitis, type 1 diabetes, autoimmune hepatitis, inflammatory bowel disease, alopecia areata, and systemic lupus erythematosus), allergies, and organ transplantation. However, they play negative roles in infections and various cancers. Several immunosuppressive functions and mechanisms of MDSCs have been determined in different disease conditions. This review comprehensively discusses the associations between MDSCs and various pathological conditions and briefly describes therapeutic approaches.

Pre-Existing Immunity Predicts Response to First-Line Immunotherapy in Non-Small Cell Lung Cancer Patients

T-cell-mediated anti-tumoral responses may have significant clinical relevance as a biomarker for response to immunotherapy. The value of peripheral blood pre-existing tumor antigen-specific T cells (PreI+) as a predictive immunotherapy biomarker in NSCLC patients was investigated, along with the frequency of various circulating immune cells. Fifty-two treatment-naïve, stage III/IV NSCLC patients, treated with front-line immune checkpoint inhibitors (ICI)-containing regimens were enrolled. PreI was calculated as the percentages of CD3+IFNγ+ cells after in vitro co-cultures of PBMCs with peptides against four different Tumor-Associated Antigens (TAA). Immunophenotyping of peripheral blood immune cells was performed using multicolor flow cytometry. PreI+ T cells were detected in 44% of patients. Median overall survival (OS) was significantly higher in PreI+ patients compared to PreI- patients (not reached vs. 321 days, respectively; p = 0.014). PreI+ patients had significantly higher numbers of possible exhausted CD3+CD8+PD-1+ cells and lower percentages of immunosuppressive Tregs compared to PreI- patients. Additionally, patients with PreI+ and low numbers of peripheral blood M-MDSCs had a significant survival advantage compared to the rest of the patients. Thus, combining pre-existing tumor antigen-specific immunity before initiation of ICI in NSCLC patients with selected immune-suppressive cells could identify patients who have a favorable clinical outcome when treated with ICI-containing regimens.

Cell of origin alters myeloid-mediated immunosuppression in lung adenocarcinoma

Solid carcinomas are often highly heterogenous cancers, arising from multiple epithelial cells of origin. Yet, how the cell of origin influences the response of the tumor microenvironment is poorly understood. Lung adenocarcinoma (LUAD) arises in the distal alveolar epithelium which is populated primarily by alveolar epithelial type I (AT1) and type II (AT2) cells. It has been previously reported that Gramd2 + AT1 cells can give rise to a histologically-defined LUAD that is distinct in pathology and transcriptomic identity from that arising from Sftpc + AT2 cells1,2. To determine how cells of origin influence the tumor immune microenvironment (TIME) landscape, we comprehensively characterized transcriptomic, molecular, and cellular states within the TIME of Gramd2 + AT1 and Sftpc + AT2-derived LUAD using KRASG12D oncogenic driver mouse models. Myeloid cells within the Gramd2 + AT1-derived LUAD TIME were increased, specifically, immunoreactive monocytes and tumor associated macrophages (TAMs). In contrast, the Sftpc + AT2 LUAD TIME was enriched for Arginase-1+ myeloid derived suppressor cells (MDSC) and TAMs expressing profiles suggestive of immunosuppressive function. Validation of immune infiltration was performed using flow cytometry, and intercellular interaction analysis between the cells of origin and major myeloid cell populations indicated that cell-type specific markers SFTPD in AT2 cells and CAV1 in AT1 cells mediated unique interactions with myeloid cells of the differential immunosuppressive states within each cell of origin mouse model. Taken together, Gramd2 + AT1-derived LUAD presents with an anti-tumor, immunoreactive TIME, while the TIME of Sftpc + AT2-derived LUAD has hallmarks of immunosuppression. This study suggests that LUAD cell of origin influences the composition and suppression status of the TIME landscape and may hold critical implications for patient response to immunotherapy.

Increased circulating polymorphonuclear myeloid-derived suppressor cells are associated with prognosis of metastatic castration-resistant prostate cancer

Introduction

Myeloid-derived suppressor cell (MDSC) exhibits immunosuppressive functions and affects cancer progression, but its relationship with prostate cancer remains unclear. We elucidated the association of polymorphonuclear MDSC (PMN-MDSC) and monocytic MDSC (M-MDSC) levels of the total peripheral blood mononuclear cells (PBMCs) with prostate cancer progression and evaluated their roles as prognostic indicators.

Methods

We enrolled 115 patients with non-metastatic hormone-sensitive prostate cancer (nmHSPC, n = 62), metastatic hormone-sensitive prostate cancer (mHSPC, n = 23), and metastatic castration-resistant prostate cancer (mCRPC, n = 30). Subsequently, the proportions of MDSCs in each disease progression were compared. Log-rank tests and multivariate Cox regression analyses were performed to ascertain the associations of overall survival.

Results

The patients with mCRPC had significantly higher PMN-MDSC percentage than those with nmHSPC and mHSPC (P = 7.73 × 10-5 and 0.0014). Significantly elevated M-MDSC levels were observed in mCRPC patients aged <70 years (P = 0.016) and with a body mass index (BMI) <25 kg/m2 (P = 0.043). The high PMN-MDSC group had notably shorter median survival duration (159 days) than the low PMN-MDSC group (768 days, log-rank P = 0.018). In the multivariate analysis including age, BMI, and MDSC subset, PMN-MDSC was significantly associated with prognosis (hazard ratios, 3.48; 95% confidence interval: 1.05-11.56, P = 0.042).

Discussion

PMN-MDSC levels are significantly associated with mCRPC prognosis. Additionally, we highlight the remarkable associations of age and BMI with M-MDSC levels in mCRPC, offering novel insights into MDSC dynamics in prostate cancer progression.

ACTL6A: unraveling its prognostic impact and paving the way for targeted therapeutics in carcinogenesis

Introduction: Increased Actin-like 6A (ACTL6A) expression is associated with various cancers, but its comprehensive investigation across different malignancies is lacking. We aimed to analyze ACTL6A as a potential oncogene and therapeutic target using bioinformatics tools. Methods: We comprehensively analyzed ACTL6A expression profiles across human malignancies, focusing on correlations with tumor grade, stage, metastasis, and patient survival. Genetic alterations were examined, and the epigenetic landscape of ACTL6A was assessed using rigorous methods. The impact of ACTL6A on immune cell infiltration in the tumor microenvironment was evaluated, along with molecular docking studies and machine learning models. Results: Our analysis revealed elevated ACTL6A expression in various tumors, correlating with poor prognostic indicators such as tumor grade, stage, metastasis, and patient survival. Genetic mutations and epigenetic modifications were identified, along with associations with immune cell infiltration and key cellular pathways. Machine learning models demonstrated ACTL6A's potential for cancer detection. Discussion: ACTL6A emerges as a promising diagnostic and therapeutic target in cancer, with implications for prognosis and therapy. Our study provides comprehensive insights into its carcinogenic actions, highlighting its potential as both a prognostic indicator and a target for anti-cancer therapy. This integrative approach enhances our understanding of ACTL6A's role in cancer pathogenesis and treatment.

Mechanisms of myeloid-derived suppressor cell-mediated immunosuppression in colorectal cancer and related therapies

Severe immunosuppression is a hallmark of colorectal cancer (CRC). Myeloid-derived suppressor cells (MDSCs), one of the most abundant components of the tumor stroma, play an important role in the invasion, metastasis, and immune escape of CRC. MDSCs create an immunosuppressive microenvironment by inhibiting the proliferation and activation of immunoreactive cells, including T and natural killer cells, as well as by inducing the proliferation of immunosuppressive cells, such as regulatory T cells and tumor-associated macrophages, which, in turn, promote the growth of cancer cells. Thus, MDSCs are key contributors to the emergence of an immunosuppressive microenvironment in CRC and play an important role in the breakdown of antitumor immunity. In this narrative review, we explore the mechanisms through which MDSCs contribute to the immunosuppressive microenvironment, the current therapeutic approaches and technologies targeting MDSCs, and the therapeutic potential of modulating MDSCs in CRC treatment. This study provides ideas and methods to enhance survival rates in patients with CRC.

Effect of thymalfasin on myeloid-derived suppressor cells in patients with non-small cell lung cancer

OBJECTIVE

To observe the effect of thymalfasin on myeloid-derived suppressor cells (MDSCs) subsets in peripheral blood of patients with non-small cell lung cancer (NSCLC).

METHODS

50 cases of NSCLC (NSCLC group) diagnosed in Chest Hospital of Jiangxi Province were selected as the research subjects, and 50 healthy subjects who underwent physical examination in our hospital during the same period were selected as the healthy control group. The expression of HLA-DR-CD14-CD33+ MDSCs in peripheral blood mononuclear cells and tumor tissue single cell suspension of NSCLC patients before and after thymalfasin treatment was explored by flow cytometry.

RESULTS

The proportion of MDSCs in peripheral blood of NSCLC group was 1.70±0.52%, which was significantly higher than that in peripheral blood (0.51±0.15%) of healthy controls (P < 0.05). The proportion of HLA-DR-CD14-CD33+ MDSCs in the tissues of NSCLC group was 1.65±0.43% before treatment and 1.15±0.50% after treatment (P < 0.05). The proportion of MDSCs in peripheral blood of NSCLC patients before treatment was 1.70±0.52%, and that after treatment was 0.59±0.18% (P < 0.05).

CONCLUSION

Thymalfasin can reduce the number of MDSCs in peripheral blood mononuclear cells. The application of thymalfasin in the treatment of NSCLC patients can help to enhance the anti-tumor effect.

Eosinophils, basophils and myeloid-derived suppressor cells in chronic Loa loa infection and its treatment in an endemic setting

BACKGROUND

Chronic infection by Loa loa remains an unsolved immunological paradox. Despite harboring subcutaneously migrating adult worms and often high densities of microfilariae, most patients experience only relatively mild symptoms, yet microfilaricidal treatment can trigger life-threatening inflammation. Here, we investigated innate cell populations hypothesized to play a role in these two faces of the disease, in an endemic population in Gabon.

METHODOLOGY/PRINCIPAL FINDINGS

We analyzed numbers and activation of eosinophils and basophils, as well as myeloid-derived suppressor cell (MDSC) subsets and associated circulating cytokine levels by flow cytometry in sex- and age-matched L. loa-uninfected (LL-), -amicrofilaraemic (MF-) and -microfilaraemic (MF+) individuals (n = 42), as well as microfilaraemic individuals treated with albendazole (n = 26). The percentage of eosinophils was lower in LL- (3.0%) than in the combined L. loa-infected population, but was similar in MF+ (13.1%) and MF- (12.3%). Upon treatment of MF+, eosinophilia increased from day 0 (17.2%) to day 14 (24.8%) and had decreased below baseline at day 168 (6.3%). Expression of the eosinophil activation marker CD123 followed the same pattern as the percentage of eosinophils, while the inverse was observed for CD193 and to some extent CD125. Circulating IL-5 levels after treatment followed the same pattern as eosinophil dynamics. Basophil numbers did not differ between infection states but increased after treatment of MF+. We did not observe differences in MDSC numbers between infection states or upon treatment.

CONCLUSIONS/SIGNIFICANCE

We demonstrate that both chronic infection and treatment of L. loa microfilaraemia are associated with eosinophil circulation and distinct phenotypical activation markers that might contribute to inflammatory pathways in this setting. In this first ever investigation into MDSC in L. loa infection, we found no evidence for their increased presence in chronic loiasis, suggesting that immunomodulation by L. loa is induced through other pathways.

Unravelling immune microenvironment features underlying tumor progression in the single-cell era

The relationship between the immune cell and tumor occurrence and progression remains unclear. Profiling alterations in the tumor immune microenvironment (TIME) at high resolution is crucial to identify factors influencing cancer progression and enhance the effectiveness of immunotherapy. However, traditional sequencing methods, including bulk RNA sequencing, exhibit varying degrees of masking the cellular heterogeneity and immunophenotypic changes observed in early and late-stage tumors. Single-cell RNA sequencing (scRNA-seq) has provided significant and precise TIME landscapes. Consequently, this review has highlighted TIME cellular and molecular changes in tumorigenesis and progression elucidated through recent scRNA-seq studies. Specifically, we have summarized the cellular heterogeneity of TIME at different stages, including early, late, and metastatic stages. Moreover, we have outlined the related variations that may promote tumor occurrence and metastasis in the single-cell era. The widespread applications of scRNA-seq in TIME will comprehensively redefine the understanding of tumor biology and furnish more effective immunotherapy strategies.

ΔNp63 regulates MDSC survival and metabolism in triple-negative breast cancer

Triple-negative breast cancer (TNBC) contributes greatly to mortality of breast cancer, demanding new targetable options. We have shown that TNBC patients have high ΔNp63 expression in tumors. However, the function of ΔNp63 in established TNBC is yet to be explored. In current studies, targeting ΔNp63 with inducible CRISPR knockout and Histone deacetylase inhibitor Quisinostat showed that ΔNp63 is important for tumor progression and metastasis in established tumors by promoting myeloid-derived suppressor cell (MDSC) survival through tumor necrosis factor alpha. Decreasing ΔNp63 levels are associated with decreased CD4+ and FOXP3+ T-cells but increased CD8+ T-cells. RNA sequencing analysis indicates that loss of ΔNp63 alters multiple MDSC properties such as lipid metabolism, chemotaxis, migration, and neutrophil degranulation besides survival. We further demonstrated that targeting ΔNp63 sensitizes chemotherapy. Overall, we showed that ΔNp63 reprograms the MDSC-mediated immunosuppressive functions in TNBC, highlighting the benefit of targeting ΔNp63 in chemotherapy-resistant TNBC.

Etiology of lung carcinoma and treatment through medicinal plants, marine plants and green synthesized nanoparticles: A comprehensive review

Lung cancer, a leading global cause of mortality, poses a significant public health challenge primarily linked to tobacco use. While tobacco contributes to over 90% of cases, factors like dietary choices and radiation exposure also play a role. Despite potential benefits from early detection, cancer patients face hurdles, including drug resistance, chemotherapy side effects, high treatment costs, and limited healthcare access. Traditional medicinal plant knowledge has recently unveiled diverse cancer chemopreventive agents from terrestrial and marine sources. These phytochemicals regulate intricate molecular processes, influencing the immune system, apoptosis, cell cycle, proliferation, carcinogen elimination, and antioxidant levels. In pursuing cutting-edge strategies to combat the diverse forms of cancer, technological advancements have spurred innovative approaches. Researchers have focused on the green synthesis of metallic nanoparticles using plant metabolites. This method offers distinct advantages over conventional physical and chemical synthesis techniques, such as cost-effectiveness, biocompatibility, and energy efficiency. Metallic nanoparticles, through various pathways such as the generation of reactive oxygen species, modulation of enzyme activity, DNA fragmentation, disruption of signaling pathways, perturbation of cell membranes, and interference with mitochondrial function resulting in DNA damage, cell cycle arrest, and apoptosis, exhibit significant potential for preventive applications. Thus, the amalgamation of phytocompounds and metallic nanoparticles holds promise as a novel approach to lung cancer therapy. However, further refinements and advancements are necessary to enhance the environmentally friendly process of metallic nanoparticle synthesis.

Identification of Key Genes Associated with Tumor Microenvironment Infiltration and Survival in Gastric Adenocarcinoma via Bioinformatics Analysis

OBJECTIVE

Gastric carcinoma (GC) is the fifth most commonly diagnosed cancer and the third leading cause of cancer-related deaths globally. The tumor microenvironment plays a significant role in the pathogenesis, prognosis, and response to immunotherapy. However, the immune-related molecular mechanisms underlying GC remain elusive. Bioinformatics analysis of the gene expression of GC and paracancerous healthy tissues from the same patient was performed to identify the key genes and signaling pathways, as well as their correlation to the infiltration of the tumor microenvironment (TME) by various immune cells related to GC development.

METHODS

We employed GSE19826, a gene expression profile from the Gene Expression Omnibus (GEO), for our analysis. Functional enrichment analysis of Differentially Expressed Genes (DEGs) was conducted using the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes database.

RESULTS

Cytoscape software facilitated the identification of nine hub DEGs, namely, FN1, COL1A1, COL1A2, THBS2, COL3A1, COL5A1, APOE, SPP1, and BGN. Various network analysis algorithms were applied to determine their high connectivity. Among these hub genes, FN1, COL1A2, THBS2, COL3A1, COL5A1, and BGN were found to be associated with a poor prognosis for GC patients. Subsequent analysis using the TIMER database revealed the infiltration status of the TME concerning the overexpression of these six genes. Specifically, the abovementioned genes demonstrated direct correlations with cancer-associated fibroblasts, M1 and M2 macrophages, myeloid-derived suppressor cells, and activated dendritic cells.

CONCLUSION

Our findings suggest that the identified hub genes, particularly BGN, FN1, COL1A2, THBS2, COL3A1, and COL5A1, play crucial roles in GC prognosis and TME cell infiltration. This comprehensive analysis enhances our understanding of the molecular mechanisms underlying GC development and may contribute to the identification of potential therapeutic targets and prognostic markers for GC patients.

Oleuropein-driven reprogramming of the myeloid cell compartment to sensitise tumours to PD-1/PD-L1 blockade strategies

BACKGROUND

Previous studies have shown that functional systemic immunity is required for the efficacy of PD-1/PD-L1 blockade immunotherapies in cancer. Hence, systemic reprogramming of immunosuppressive dysfunctional myeloid cells could overcome resistance to cancer immunotherapy.

METHODS

Reprogramming of tumour-associated myeloid cells with oleuropein was studied by quantitative differential proteomics, phenotypic and functional assays in mice and lung cancer patients. Combinations of oleuropein and two different delivery methods of anti-PD-1 antibodies were tested in colorectal cancer tumour models and in immunotherapy-resistant lung cancer models.

RESULTS

Oleuropein treatment reprogrammed monocytic and granulocytic myeloid-derived suppressor cells, and tumour-associated macrophages towards differentiation of immunostimulatory subsets. Oleuropein regulated major differentiation programmes associated to immune modulation in myeloid cells, which potentiated T cell responses and PD-1 blockade. PD-1 antibodies were delivered by two different strategies, either systemically or expressed within tumours using a self-amplifying RNA vector. Combination anti-PD-1 therapies with oleuropein increased tumour infiltration by immunostimulatory dendritic cells in draining lymph nodes, leading to systemic antitumour T cell responses. Potent therapeutic activities were achieved in colon cancer and lung cancer models resistant to immunotherapies, even leading to complete tumour regression.

DISCUSSION

Oleuropein significantly improves the outcome of PD-1/PD-L1 blockade immunotherapy strategies by reprogramming myeloid cells.

Increased monocytic myeloid-derived suppressor cells in type 2 diabetes correlate with hyperglycemic and was a risk factor of infection and tumor occurrence

To investigate the frequency of monocytic myeloid-derived suppressor cells (M-MDSCs) in type 2 diabetes mellitus (T2DM) patients and explore the potential associations between M-MDSCs, glycemic control, and the occurrence of infections and tumor. 102 healthy and 77 T2DM individuals were enrolled. We assessed the M-MDSCs frequency, levels of fasting plasma glucose (FPG), haemoglobin A1c (HbA1c), and other relevant indicators. Each patient underwent a follow-up of at least 6 months after M-MDSCs detection. The M-MDSCs frequency was significantly higher in patients with poor glycemic control (PGC) compared to the healthy population (P < 0.001), whereas there was no significant difference between patients with good glycemic control and the healthy (P > 0.05). There was a positive correlation between the M-MDSCs frequency and FPG, HbA1c (R = 0.517 and 0.315, P < 0.001, respectively). T2DM patients with abnormally increased M-MDSCs have a higher incidence of infection and tumor (48.57% and 11.43% respectively). Our results shed new light on the pathogenesis of T2DM, help to understand why T2DM patients are susceptible to infection and tumor and providing novel insights for future prevention and treatment of T2DM.

Identification of tumor heterogeneity associated with KRAS/TP53 co-mutation status in lung adenocarcinoma based on single-cell RNA sequencing

Lung cancer stands as the predominant cause of cancer-related mortality globally. Lung adenocarcinoma (LUAD), being the most prevalent subtype, garners extensive attention due to its notable heterogeneity, which significantly influences tumor development and treatment approaches. This research leverages single-cell RNA sequencing (scRNA-seq) datasets to delve into the impact of KRAS/TP53 co-mutation status on LUAD. Moreover, utilizing the TCGA-LUAD dataset, we formulated a novel predictive risk model, comprising seven prognostic genes, through LASSO regression, and subjected it to both internal and external validation sets. The study underscores the profound impact of KRAS/TP53 co-mutational status on the tumor microenvironment (TME) of LUAD. Crucially, KRAS/TP53 co-mutation markedly influences the extent of B cell infiltration and various immune-related pathways within the TME. The newly developed predictive risk model exhibited robust performance across both internal and external validation sets, establishing itself as a viable independent prognostic factor. Additionally, in vitro experiments indicate that MELTF and PLEK2 can modulate the invasion and proliferation of human non-small cell lung cancer cells. In conclusion, we elucidated that KRAS/TP53 co-mutations may modulate TME and patient prognosis by orchestrating B cells and affiliated pathways. Furthermore, we spotlight that MELTF and PLEK2 not only function as prognostic indicators for LUAD, but also lay the foundation for the exploration of innovative therapeutic approaches.

A review of natural products targeting tumor immune microenvironments for the treatment of lung cancer

Lung cancer (LC) produces some of the most malignant tumors in the world, with high morbidity and mortality. Tumor immune microenvironment (TIME), a component of the tumor microenvironment (TME), are critical in tumor development, immune escape, and drug resistance. The TIME is composed of various immune cells, immune cytokines, etc, which are important biological characteristics and determinants of tumor progression and outcomes. In this paper, we reviewed the recently published literature and discussed the potential uses of natural products in regulating TIME. We observed that a total of 37 natural compounds have been reported to exert anti-cancer effects by targeting the TIME. In different classes of natural products, terpenoids are the most frequently mentioned compounds. TAMs are one of the most investigated immune cells about therapies with natural products in TIME, with 9 natural products acting through it. 17 natural products exhibit anti-cancer properties in LC by modulating PD-1 and PD-L1 protein activity. These natural products have been extensively evaluated in animal and cellular LC models, but their clinical trials in LC patients are lacking. Based on the current review, we have revealed that the mechanisms of LC can be treated with natural products through TIME intervention, resulting in a new perspective and potential therapeutic drugs.

Zaki M, Soltan MA, Noreldin AE. Oncogenic Potential of Replication Factor C Subunit 4: Correlations with Tumor Progression and Assessment of Potential Inhibitors

Replication Factor C Subunit 4 (RFC4), an oncogene implicated in many human cancers, has yet to be extensively studied in many cancer types to determine its expression patterns and tumor tissue function. Various bioinformatics tools were used to analyze RFC4 as a potential oncogene and therapeutic target across many cancers. We first examined RFC4 expression levels in several human tumor types to determine relationships with tumor grade, stage, metastasis, and patient survival. We also examined RFC4's genetic changes, epigenetic methylation, and effect on tumor microenvironment (TME) immune cell infiltration. We also analyzed RFC4's connections with immunological checkpoints to identify potential molecular pathways involved in carcinogenesis. Our findings show that RFC4 is upregulated in several tumor types and associated with poor prognoses in many human cancers. This study shows that RFC4 significantly affects the tumor immunological microenvironment, specifically immune cell populations. Finally, we screened for RFC4-inhibiting pharmacological compounds with anti-cancer potential. This study fully elucidates RFC4's carcinogenic activities, emphasizing its potential as a prognostic biomarker and a target for anti-cancer therapy.

Universal Anti-CD7 CAR-T Cells Targeting T-ALL and Functional Analysis of CD7 Antigen on T/CAR-T Cells

Chimeric antigen receptor T (CAR-T) cell therapy initiates new methods and turns the scale of clinical treatment on relapsed/refractory acute T lymphoblastic leukemia (T-ALL). In this study, we generated the second-generation CD7-targeting CAR-T cells with a new antigen-binding single-chain variable fragment sequence and made it universal via CRISPR-based knockout of TRAC and CD7 genes (termed UCAR-T). The CD7 UCAR-T cells can efficiently proliferate and lyse T-ALL tumor cell in vitro, along with prominent proinflammatory cytokines secretion. A Jurkat-based xenograft mouse model further verified the superior cytotoxicity of the UCAR-T cells in vivo. During the UCAR-T construction, we observed a CD4/CD8 ratio shift among CD7-/- T/CAR-T cells, which motivated us to further analyze the effects of CD7 antigen on T/CAR-T cells. We sorted out CD7+/- T or anti-CD19 CAR-T cells after partially CD7 knockout and performed functional, phenotypic detection, as well as translational analysis. CD7-/- CAR-T cells tended to be CD8 negative and showed slightly better cytotoxicity at long-term assay. RNA-seq further confirmed an elevation of activated CD4 memory cell subpopulation. However, limited distinction on crucial regulatory genes and pathways was revealed, suggesting the safety and feasibility of UCAR-T application as well as the potential translational rather than transcriptional regulation of CD7 antigen.

Innate immunity: Looking beyond T-cells in radiation and immunotherapy combinations

Radiation therapy is an established and effective anti-cancer treatment modality. Extensive pre-clinical experimentation has demonstrated that the pro-inflammatory properties of irradiation may be synergistic with checkpoint immunotherapy. Radiation induces double-stranded DNA breaks (dsDNA). Sensing of the dsDNA activates the cGAS/STING pathway, producing Type 1 interferons essential to recruiting antigen-presenting cells (APCs). Radiation promotes cytotoxic CD8 T-cell recruitment by releasing tumour-associated antigens captured and cross-presented by surveying antigen-presenting cells. Radiation-induced vascular normalisation may further promote T-cell trafficking and drug delivery. Radiation is also immunosuppressive. Recruitment of regulatory T cells (Tregs) and innate cells such as myeloid-derived suppressive cells (m-MDSCs) all counteract the immunostimulatory properties of radiation. Many innate immune cell types operate at the interface of the adaptive immune response. Innate immune cells, such as m-MDSCs, can exert their immunosuppressive effects by expressing immune checkpoints such as PD-L1, further highlighting the potential of combined radiation and checkpoint immunotherapy. Several early-phase clinical studies investigating the combination of radiation and immunotherapy have been disappointing. A greater appreciation of radiotherapy's impact on the innate immune system is essential to optimise radioimmunotherapy combinations. This review will summarise the impact of radiotherapy on crucial cells of the innate immune system and vital immunosuppressive cytokines.

Exploiting innate immunity for cancer immunotherapy

Immunotherapies have revolutionized the treatment paradigms of various types of cancers. However, most of these immunomodulatory strategies focus on harnessing adaptive immunity, mainly by inhibiting immunosuppressive signaling with immune checkpoint blockade, or enhancing immunostimulatory signaling with bispecific T cell engager and chimeric antigen receptor (CAR)-T cell. Although these agents have already achieved great success, only a tiny percentage of patients could benefit from immunotherapies. Actually, immunotherapy efficacy is determined by multiple components in the tumor microenvironment beyond adaptive immunity. Cells from the innate arm of the immune system, such as macrophages, dendritic cells, myeloid-derived suppressor cells, neutrophils, natural killer cells, and unconventional T cells, also participate in cancer immune evasion and surveillance. Considering that the innate arm is the cornerstone of the antitumor immune response, utilizing innate immunity provides potential therapeutic options for cancer control. Up to now, strategies exploiting innate immunity, such as agonists of stimulator of interferon genes, CAR-macrophage or -natural killer cell therapies, metabolic regulators, and novel immune checkpoint blockade, have exhibited potent antitumor activities in preclinical and clinical studies. Here, we summarize the latest insights into the potential roles of innate cells in antitumor immunity and discuss the advances in innate arm-targeted therapeutic strategies.

Targeting M-MDSCs enhances the therapeutic effect of BNCT in the 4-NQO-induced murine head and neck squamous cell carcinoma model

Purpose

Malignant head and neck squamous cell carcinoma (HNSCC) is characterized by a poor prognosis and resistance to conventional radiotherapy. Infiltrating myeloid-derived suppressive cells (MDSCs) is prominent in HNSCC and is linked to immune suppression and tumor aggressiveness. This study aimed to investigate the impact of boron neutron capture therapy (BNCT) on the MDSCs in the tumor microenvironment and peripheral blood and to explore the potential for MDSCs depletion combined with BNCT to reactivate antitumor immunity.

Methods and materials

Carcinogen, 4-NQO, -induced oral tumors were irradiated with a total physical dose of 2 Gy BNCT in Tsing Hua Open Reactor (THOR). Flow cytometry and immunohistochemistry accessed the dynamics of peripheral MDSCs and infiltrated MDSCs within the tumor microenvironment. Mice were injected with an inhibitor of CSF-1 receptor (CSF-1R), PLX3397, to determine whether modulating M-MDSCs could affect mice survival after BNCT.

Results

Peripheral CD11b+Ly6ChighLy6G- monocytic-MDSCs (M-MDSCs), but not CD11b+Ly6CloLy6Ghigh polymorphonuclear-MDSCs (PMN-MDSCs), increased as tumor progression. After BNCT treatment, there were temporarily decreased and persistent increases of M-MDSCs thereafter, either in peripheral blood or in tumors. The administration of PLX-3397 hindered BNCT-caused M-MDSCs infiltration, prolonged mice survival, and activated tumor immunity by decreasing tumor-associated macrophages (TAMs) and increasing CD8+ T cells.

Conclusion

M-MDSCs were recruited into 4-NQO-induced tumors after BNCT, and their number was also increased in peripheral blood. Assessment of M-MDSCs levels in peripheral blood could be an index to determine the optimal intervention window. Their temporal alteration suggests an association with tumor recurrence after BNCT, making M-MDSCs a potential intervention target. Our preliminary results showed that PLX-3397 had strong M-MDSCs, TAMs, and TIL (tumor-infiltrating lymphocyte) modulating effects that could synergize tumor control when combined with BNCT.

Potential targeting of the tumor microenvironment to improve cancer virotherapy

In 2015, oncolytic virotherapy was approved for clinical use, and in 2017, recombinant adeno-associated virus (AAV) delivery was also approved. However, systemic administration remains challenging due to the limited number of viruses that successfully reach the target site. Although the US Food and Drug Administration (FDA) permits the use of higher doses of AAV to achieve greater rates of transduction, most AAV still accumulates in the liver, potentially leading to toxicity there and elsewhere. Targeting the tumor microenvironment is a promising strategy for cancer treatment due to the critical role of the tumor microenvironment in controlling tumor progression and influencing the response to therapies. Newly discovered evidence indicates that administration routes focusing on the tumor microenvironment can promote delivery specificity and transduction efficacy within the tumor. Here, we review approaches that involve modifying viral surface features, modulating the immune system, and targeting the physicochemical characteristics in tumor microenvironment to regulate therapeutic delivery. Targeting tumor acidosis presents advantages that can be leveraged to enhance virotherapy outcomes and to develop new therapeutic approaches that can be integrated with standard treatments.

Small Molecule Targeting Immune Cells: A Novel Approach for Cancer Treatment

Conventional and cancer immunotherapies encompass diverse strategies to address various cancer types and stages. However, combining these approaches often encounters limitations such as non-specific targeting, resistance development, and high toxicity, leading to suboptimal outcomes in many cancers. The tumor microenvironment (TME) is orchestrated by intricate interactions between immune and non-immune cells dictating tumor progression. An innovative avenue in cancer therapy involves leveraging small molecules to influence a spectrum of resistant cell populations within the TME. Recent discoveries have unveiled a phenotypically diverse cohort of innate-like T (ILT) cells and tumor hybrid cells (HCs) exhibiting novel characteristics, including augmented proliferation, migration, resistance to exhaustion, evasion of immunosurveillance, reduced apoptosis, drug resistance, and heightened metastasis frequency. Leveraging small-molecule immunomodulators to target these immune players presents an exciting frontier in developing novel tumor immunotherapies. Moreover, combining small molecule modulators with immunotherapy can synergistically enhance the inhibitory impact on tumor progression by empowering the immune system to meticulously fine-tune responses within the TME, bolstering its capacity to recognize and eliminate cancer cells. This review outlines strategies involving small molecules that modify immune cells within the TME, potentially revolutionizing therapeutic interventions and enhancing the anti-tumor response.

Nivolumab after Induction Chemotherapy in Previously Treated Non-Small-Cell Lung Cancer Patients with Low PD-L1 Expression

This study aimed to investigate whether cyclophosphamide (C) and adriamycin (A) induction therapy (IT) prior to nivolumab could enhance the efficacy of nivolumab in previously treated patients with non-squamous (NSQ) non-small-cell lung cancer (NSCLC) with less than 10% programmed death-ligand 1 (PD-L1) expression. Twenty-two enrolled patients received four cycles of CA-IT every 3 weeks. Nivolumab was given 360 mg every 3 weeks from the second cycle and 480 mg every 4 weeks after four cycles of CA-IT. The median progression-free survival (PFS) and overall survival (OS) were 2.4 months and 11.6 months, respectively. Fluorescence-activated cell sorting revealed the lowest ratio of myeloid-derived suppressor cells (MDSCs) to CD8+T-cells in the responders. Proteomic analysis identified a consistent upregulation of extracellular matrix-receptor interactions and phagosome pathways in the responders. Among the differentially expressed proteins, the transferrin receptor protein (TFRC) was higher in the responders before treatment (fold change > 1.2). TFRC validation with an independent cohort showed the prognostic significance of either OS or PFS in patients with low PD-L1 expression. In summary, CA-IT did not improve nivolumab efficacy in NSQ-NSCLCs with low PD-L1 expression; however, it induced decreasing MDSC, resulting in a durable response. Higher baseline TFRC levels predicted a favorable response to nivolumab in NSCLC with low PD-L1 expression.

Current immune therapeutic strategies in advanced or metastatic non-small cell lung cancer

ABSTRACT

Immune escape mechanisms in non-small cell lung cancer (NSCLC) can disrupt every step of the anti-cancer immune response. In recent years, an increased understanding of the specific mechanisms fueling immune escape has allowed for the development of numerous immunotherapeutic treatments that have been introduced into the clinical practice. The advent of immunotherapy has dramatically changed the current treatment landscape of advanced or metastatic NSCLC because of its durable efficacy and manageable toxicity. In this review, we will first present a brief overview of recent evidence on immune escape mechanisms in NSCLC. We will then discuss the current promising immunotherapeutic strategies in advanced or metastatic NSCLC tumors.

The recent progress of myeloid-derived suppressor cell and its targeted therapies in cancers

Myeloid-derived suppressor cells (MDSCs) are an immature group of myeloid-derived cells generated from myeloid cell precursors in the bone marrow. MDSCs appear almost exclusively in pathological conditions, such as tumor progression and various inflammatory diseases. The leading function of MDSCs is their immunosuppressive ability, which plays a crucial role in tumor progression and metastasis through their immunosuppressive effects. Since MDSCs have specific molecular features, and only a tiny amount exists in physiological conditions, MDSC-targeted therapy has become a promising research direction for tumor treatment with minimal side effects. In this review, we briefly introduce the classification, generation and maturation process, and features of MDSCs, and detail their functions under various circumstances. The present review specifically demonstrates the environmental specificity of MDSCs, highlighting the differences between MDSCs from cancer and healthy individuals, as well as tumor-infiltrating MDSCs and circulating MDSCs. Then, we further describe recent advances in MDSC-targeted therapies. The existing and potential targeted drugs are divided into three categories, monoclonal antibodies, small-molecular inhibitors, and peptides. Their targeting mechanisms and characteristics have been summarized respectively. We believe that a comprehensive in-depth understanding of MDSC-targeted therapy could provide more possibilities for the treatment of cancer.

Unveiling tumor immune evasion mechanisms: abnormal expression of transporters on immune cells in the tumor microenvironment

The tumor microenvironment (TME) is a crucial driving factor for tumor progression and it can hinder the body's immune response by altering the metabolic activity of immune cells. Both tumor and immune cells maintain their proliferative characteristics and physiological functions through transporter-mediated regulation of nutrient acquisition and metabolite efflux. Transporters also play an important role in modulating immune responses in the TME. In this review, we outline the metabolic characteristics of the TME and systematically elaborate on the effects of abundant metabolites on immune cell function and transporter expression. We also discuss the mechanism of tumor immune escape due to transporter dysfunction. Finally, we introduce some transporter-targeted antitumor therapeutic strategies, with the aim of providing new insights into the development of antitumor drugs and rational drug usage for clinical cancer therapy.

Integrated analyses of single-cell transcriptomics identify metastasis-associated myeloid subpopulations in breast cancer lung metastasis

Lung metastasis of breast cancer is closely associated with patient morbidity and mortality, which correlates with myeloid cells in the lung microenvironment. However, the heterogeneity and specificity of metastasis-associated myeloid cells have not been fully established in lung metastasis. Here, by integrating and analyzing single-cell transcriptomics, we found that myeloid subpopulations (Tppp3 ⁺ monocytes, Isg15 ⁺ macrophages, Ifit3 ⁺ neutrophils, and Il12b ⁺ DCs) play critical roles in the formation and development of the metastatic niche. Gene enrichment analyses indicate that several tumor-promoting pathways should be responsible for the process, including angiogenesis (Anxa1 and Anxa2 by Tppp3 ⁺ monocytes), immunosuppression (Isg15 and Cxcl10 by Isg15 ⁺ macrophages; Il12b and Ccl22 by Il12b ⁺ DCs), and tumor growth and metastasis (Isg15 and Isg20 by Ifit3 ⁺ neutrophils). Furthermore, we have validated these subpopulations in lung microenvironment of MMTV-PyVT transgenic mice and verified their association with poor progression of human breast cancer. Also, our results elucidated a crosstalk network among four myeloid subpopulations by cell-cell communication analysis. This study, therefore, highlights the crucial role of myeloid cells in lung metastasis and provides insights into underlying molecular mechanisms, which pave the way for therapeutic interventions in breast cancer metastasis to lung.

Epigenetic regulation in the tumor microenvironment: molecular mechanisms and therapeutic targets

Over decades, researchers have focused on the epigenetic control of DNA-templated processes. Histone modification, DNA methylation, chromatin remodeling, RNA modification, and noncoding RNAs modulate many biological processes that are crucial to the development of cancers. Dysregulation of the epigenome drives aberrant transcriptional programs. A growing body of evidence suggests that the mechanisms of epigenetic modification are dysregulated in human cancers and might be excellent targets for tumor treatment. Epigenetics has also been shown to influence tumor immunogenicity and immune cells involved in antitumor responses. Thus, the development and application of epigenetic therapy and cancer immunotherapy and their combinations may have important implications for cancer treatment. Here, we present an up-to-date and thorough description of how epigenetic modifications in tumor cells influence immune cell responses in the tumor microenvironment (TME) and how epigenetics influence immune cells internally to modify the TME. Additionally, we highlight the therapeutic potential of targeting epigenetic regulators for cancer immunotherapy. Harnessing the complex interplay between epigenetics and cancer immunology to develop therapeutics that combine thereof is challenging but could yield significant benefits. The purpose of this review is to assist researchers in understanding how epigenetics impact immune responses in the TME, so that better cancer immunotherapies can be developed.

5-FU mediated depletion of myeloid suppressor cells enhances T-cell infiltration and anti-tumor response in immunotherapy-resistant lung tumor

Tumor microenvironment (TME) is a heterogeneous system consisting of both cellular and acellular components. The growth and progression of tumors rely greatly on the nature of TME, marking it as an important target in cancer immunotherapy. Lewis Lung Carcinoma (LLC) is an established murine lung cancer model representing immunologically 'cold' tumors characterized by very few infiltrated cytotoxic T-cells, high levels of Myeloid-Derived Suppressor Cells (MDSCs) and Tumor-Associated Macrophages (TAMs). Here, we report various strategies we applied to reverse the non-immunogenic character of this cold tumor by imparting: a) immunogenic cell death using Hypericin nanoparticle-based photodynamic therapy (PDT), b) repolarising TAM using a TLR7/8 agonist, resiquimod, c) immune checkpoint inhibition using anti-PD-L1 and d) depleting MDSCs using low-dose 5-fluorouracil (5-FU) chemotherapy. Interestingly, the nano-PDT, resiquimod or anti-PD-L1 treatment had no major impact on tumor growth, whereas low-dose 5-FU-mediated depletion of MDSCs showed significant anti-tumor effect, primarily caused by the increased infiltration of CD8⁺ cytotoxic T-cells (∼96%). Though we have tested combining PDT with resiquimod or 5-FU for any synergistic effect, low-dose 5-FU alone showed better response than combinations. In effect, we show that depletion of MDSCs using low-dose 5-FU was one of the best methods to augment infiltration of CD8⁺ cytotoxic T-cells into a cold tumor, which is resistant to conventional therapies including immune checkpoint inhibitors.

Overcoming resistance to immunotherapy by targeting GPR84 in myeloid-derived suppressor cells

Myeloid-derived suppressor cells (MDSCs) were found to gradually accumulate in the orthotopic esophageal cancer mouse model during tumor progression. Although the roles of MDSCs in promoting tumor growth and inhibiting immune response have been extensively explored, currently, there are still no effective means for targeting MDSCs clinically. The deficiency of specific markers of MDSCs was responsible for the limited strategy to eliminating in clinic. This study identified that GPR84 was exclusively overexpressed on MDSCs. It was further found that GPR84 was prominently expressed on MDSCs in clinical samples and tumor mouse models, which drives the immunosuppression on CD8⁺T cells by inhibiting PD-L1 degradation in lysosomes. Furthermore, G-CSF and GM-CSF were found to induce GPR84 expression through the STAT3/C/EBPβ signaling pathway. In addition, GPR84⁺MDSCs and PD-L1⁺MDSCs were highly accumulated in anti-PD-1 therapy-resistant patients with esophageal cancer, and high GPR84 signature risk was verified as a negative factor for the overall survival of patients with anti-PD-1 treatment. Finally, GPR84 antagonism combined with an anti-PD-1 antibody enhanced the antitumor responses. Therefore, targeting GPR84 enhanced anti-PD-1 efficacy in esophageal cancer and other malignant tumors. This combination therapy has the potential for tumor therapy in clinics.

Combining Cryo-Thermal Therapy with Anti-IL-6 Treatment Promoted the Maturation of MDSCs to Induce Long-Term Survival in a Mouse Model of Breast Cancer

Immunosuppression plays a significant role in tumor recurrence and metastasis, ultimately causing poor survival outcomes. Overcoming immunosuppression and stimulating durable antitumor immunity are essential for tumor treatment. In our previous study, a novel cryo-thermal therapy involving liquid nitrogen freezing and radiofrequency heating could reduce the proportion of Myeloid-derived suppressor cells (MDSCs), but the remaining MDSCs produced IL-6 by the NF-κB pathway, resulting in an impaired therapeutic effect. Therefore, here we combined cryo-thermal therapy with anti-IL-6 treatment to target the MDSC-dominant immunosuppressive environment, thereby optimizing the efficacy of cryo-thermal therapy. We found that combinational treatment significantly increased the long-term survival rate of breast cancer-bearing mice. Mechanistic investigation revealed that combination therapy was capable of reducing the proportion of MDSCs in the spleen and blood while promoting their maturation, which resulted in increased Th1-dominant CD4+ T-cell differentiation and enhancement of CD8+ T-mediated tumor killing. In addition, CD4+ Th1 cells promoted mature MDSCs to produce IL-7 through IFN-γ, indirectly contributing to the maintenance of Th1-dominant antitumor immunity in a positive feedback loop. Our work suggests an attractive immunotherapeutic strategy targeting the MDSC-dominant immunosuppressive environment, which would offer exciting opportunities for highly immunosuppressive and unresectable tumors in the clinic.

The role of myeloid-derived immunosuppressive cells in cardiovascular disease

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous cell population found in the bone marrow, peripheral blood, and tumor tissue. Their role is mainly to inhibit the monitoring function of innate and adaptive immune cells, which leads to the escape of tumor cells and promotes tumor development and metastasis. Moreover, recent studies have found that MDSCs are therapeutic in several autoimmune disorders due to their strong immunosuppressive ability. Additionally, studies have found that MDSCs have an important role in the formation and progression of other cardiovascular diseases, such as atherosclerosis, acute coronary syndrome, and hypertension. In this review, we will discuss the role of MDSCs in the pathogenesis and treatment of cardiovascular disease.

CAR-T Cells in the Treatment of Ovarian Cancer: A Promising Cell Therapy

Ovarian cancer (OC) is among the most common gynecologic malignancies with a poor prognosis and a high mortality rate. Most patients are diagnosed at an advanced stage (stage III or IV), with 5-year survival rates ranging from 25% to 47% worldwide. Surgical resection and first-line chemotherapy are the main treatment modalities for OC. However, patients usually relapse within a few years of initial treatment due to resistance to chemotherapy. Cell-based therapies, particularly adoptive T-cell therapy and chimeric antigen receptor T (CAR-T) cell therapy, represent an alternative immunotherapy approach with great potential for hematologic malignancies. However, the use of CAR-T-cell therapy for the treatment of OC is still associated with several difficulties. In this review, we comprehensively discuss recent innovations in CAR-T-cell engineering to improve clinical efficacy, as well as strategies to overcome the limitations of CAR-T-cell therapy in OC.

Targeting tumor microenvironment for non-small cell lung cancer immunotherapy

The tumor microenvironment (TME) is composed of different cellular and non-cellular elements. Constant interactions between tumor cells and the TME are responsible for tumor initiation, tumor progression, and responses to therapies. Immune cells in the TME can be classified into two broad categories, namely adaptive and innate immunity. Targeting these immune cells has attracted substantial research and clinical interest. Current research focuses on identifying key molecular players and developing targeted therapies. These approaches may offer more efficient ways of treating different cancers. In this review, we explore the heterogeneity of the TME in non-small cell lung cancer, summarize progress made in targeting the TME in preclinical and clinical studies, discuss the potential predictive value of the TME in immunotherapy, and highlight the promising effects of bispecific antibodies in the era of immunotherapy.

NSC243928 Treatment Induces Anti-Tumor Immune Response in Mouse Mammary Tumor Models

NSC243928 induces cell death in triple-negative breast cancer cells in a LY6K-dependent manner. NSC243928 has been reported as an anti-cancer agent in the NCI small molecule library. The molecular mechanism of NSC243928 as an anti-cancer agent in the treatment of tumor growth in the syngeneic mouse model has not been established. With the success of immunotherapies, novel anti-cancer drugs that may elicit an anti-tumor immune response are of high interest in the development of novel drugs to treat solid cancer. Thus, we focused on studying whether NSC243928 may elicit an anti-tumor immune response in the in vivo mammary tumor models of 4T1 and E0771. We observed that NSC243928 induced immunogenic cell death in 4T1 and E0771 cells. Furthermore, NSC243928 mounted an anti-tumor immune response by increasing immune cells such as patrolling monocytes, NKT cells, B1 cells, and decreasing PMN MDSCs in vivo. Further studies are required to understand the exact mechanism of NSC243928 action in inducing an anti-tumor immune response in vivo, which can be used to determine a molecular signature associated with NSC243928 efficacy. NSC243928 may be a good target for future immuno-oncology drug development for breast cancer.

Immunosuppression by Inflammation-Stimulated Amplification of Myeloid-Derived Suppressor Cells and Changes in Expression of Immune Checkpoint HHLA2 in Chronic Obstructive Pulmonary Disease

Background

The interaction between immune checkpoint and myeloid-derived suppressor cells (MDSCs) play a significant role in inflammatory diseases. But their correlation with chronic obstructive pulmonary disease (COPD) remains unclear.

Methods

The differentially expressed immune checkpoints and immunocytes in the airway tissues of COPD patients were identified by bioinformatics analysis, followed by correlation analysis and identification of immune-related differential genes for Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analysis. The results of bioinformatics analysis were verified by ELISA and Real-Time PCR and transcriptome sequencing of the peripheral blood of both COPD patients and healthy subjects.

Results

The results of the bioinformatics analysis showed that the level of MDSCs in airway tissue and peripheral blood of COPD patients was higher than that of healthy controls. The expression of CSF1 in airway tissue and peripheral blood of COPD patients increased, and CYBB was increased in airway tissue and decreased in peripheral blood of COPD patients. The expression of HHLA2 in the airway tissue decreased in COPD patients, and showed a negative correlation with MDSCs, with a correlation coefficient of -0.37. The peripheral blood flow cytometry results indicated that MDSCs and Treg cells of COPD patients were higher than those in the healthy control group. The results of peripheral blood ELISA and RT-PCR showed that the HHLA2 and CSF1 levels in COPD patients were higher than those in the healthy control group.

Conclusion

In COPD, the bone marrow is stimulated to produce MDSCs, and a large number of MDSCs migrate to airway tissue through peripheral blood and cooperate with HHLA2 to exert an immunosuppressive effect. Whether MDSCs play an immunosuppressive effect during migration needs to be further confirmed.

The redox protein HMGB1 in cell death and cancer

SIGNIFICANCE

As a redox-sensitive protein, high-mobility group box 1 (HMGB1) is implicated in regulating stress responses to oxidative damage and cell death, which are closely related to the pathology of inflammatory diseases, including cancer.

RECENT ADVANCES

HMGB1 is a non-histone nuclear protein that acts as a DNA chaperone to control chromosomal structure and function. HMGB1 can also be released into the extracellular space and function as a damage-associated molecular pattern protein during cell death, including during apoptosis, necrosis, necroptosis, pyroptosis, ferroptosis, alkaliptosis, and cuproptosis. Once released, HMGB1 binds to membrane receptors to shape immune and metabolic responses. In addition to subcellular localization, the function and activity of HMGB1 also depends on its redox state and protein posttranslational modifications. Abnormal HMGB1 plays a dual role in tumorigenesis and anticancer therapy (e.g., chemotherapy, radiation therapy, and immunotherapy) depending on tumor types and stages.

CRITICAL ISSUES

A comprehensive understanding of the role of HMGB1 in cellular redox homeostasis is important for deciphering normal cellular functions and pathological manifestations. In this review, we discuss compartmental-defined roles of HMGB1 in regulating cell death and cancer. Understanding these advances may help us develop potential HMGB1-targeting drugs or approaches to treat oxidative stress-related diseases or pathological conditions.

FUTURE DIRECTIONS

Further studies are required to dissect the mechanism by which HMGB1 maintains redox homeostasis under different stress conditions. A multidisciplinary effort is also required to evaluate the potential applications of precisely targeting the HMGB1 pathway in human health and disease.

Myeloid-cell-specific role of Gasdermin D in promoting lung cancer progression in mice

The activities of the NLRP3 and AIM2 inflammasomes and Gasdermin D (GsdmD) are implicated in lung cancer pathophysiology but it's not clear if their contributions promote or retard lung cancer progression. Using a metastatic Lewis lung carcinoma (LLC) cell model, we show that GsdmD knockout (GsdmD^-/-) mice form significantly fewer cancer foci in lungs, exhibit markedly decreased lung cancer metastasis, and show a significant ∼50% increase in median survival rate. The cleaved forms of GsdmD and IL-1β were detected in lung tumor tissue, indicating inflammasome activity in lung tumor microenvironment (TME). Increased migration and growth of LLC cells was observed upon exposure to the conditioned media derived from inflammasome-induced wild type, but not the GsdmD^-/-, macrophages. Using bone marrow transplantations, we show a myeloid-specific contribution of GsdmD in lung cancer metastasis. Taken together, our data show that GsdmD plays a myeloid-specific role in lung cancer progression.

Inhibitory Effect of Astragalus Polysaccharide on Premetastatic Niche of Lung Cancer through the S1PR1-STAT3 Signaling Pathway

As a common malignant tumor, the morbidity and mortality of lung cancer have been rising in recent years. The concept of "premetastatic niche" may lead to a revolutionary change in antitumor metastasis therapeutic strategies. Traditional Chinese medicine with multitargets and lower poisonous agents may be a potentially effective means to intervene in the "premetastatic niche (PMN)" to prevent and treat tumor metastasis. Astragalus polysaccharide (APS) is a substance with strong immune activity in Astragalus membranaceus that has excellent biological activities such as immunomodulation, anti-inflammatory, and antitumor. In this study, we constructed a tumor lung metastasis animal model to explore the intervention mechanism of APS on the premetastatic niche. We found that APS inhibited the formation of the lung premetastatic niche and inhibited the recruitment of myeloid-derived suppressor cells (MDSCs) in the lung. Mechanistically, we showed that the proteins and gene expression of S1PR1, STAT3, and p-STAT3 in the S1PR1/STAT3 signaling pathway were suppressed by APS. In line with the above findings, our results confirmed that APS may inhibit the accumulation of MDSCs in the premetastatic niche through the intervention of the S1PR1-STAT3 signaling pathway to achieve the antitumor effect.