A2AR-mediated CXCL5 upregulation on macrophages promotes NSCLC progression via NETosis.

Tumor-associated macrophages (TAMs) are abundant in tumors and interact with tumor cells, leading to the formation of an immunosuppressive microenvironment and tumor progression. Although many studies have explored the mechanisms underlying TAM polarization and its immunosuppressive functions, understanding of its progression remains limited. TAMs promote tumor progression by secreting cytokines, which subsequently recruit immunosuppressive cells to suppress the antitumor immunity. In this study, we established an in vitro model of macrophage and non-small cell lung cancer (NSCLC) cell co-culture to explore the mechanisms of cell-cell crosstalk. We observed that in NSCLC, the C-X-C motif chemokine ligand 5 (CXCL5) was upregulated in macrophages because of the stimulation of A2AR by adenosine. Adenosine was catalyzed by CD39 and CD73 in macrophages and tumor cells, respectively. Nuclear factor kappa B (NFκB) mediated the A2AR stimulation of CXCL5 upregulation in macrophages. Additionally, CXCL5 stimulated NETosis in neutrophils. Neutrophil extracellular traps (NETs)-treated CD8+ T cells exhibited upregulation of exhaustion-related and cytosolic DNA sensing pathways and downregulation of effector-related genes. However, A2AR inhibition significantly downregulated CXCL5 expression and reduced neutrophil infiltration, consequently alleviating CD8+ T cell dysfunction. Our findings suggest a complex interaction between tumor and immune cells and its potential as therapeutic target.

IL8 derived from macrophages inhibits CD8+ T-cell function by downregulating TIM3 expression through IL8-CXCR2 axis in patients with advanced colorectal cancer.

BACKGROUND: T cell immunoglobulin and mucin domain-containing protein 3 (TIM3) is a vital immune checkpoint that regulates the immune response. However, the specific role of TIM3 in patients with colorectal cancer (CRC) have rarely been studied. In this study, we investigated the effect of TIM3 on CD8+ T cells in CRC and explored the mechanism of TIM3 regulation in tumor microenvironment (TME). METHODS: Peripheral blood and tumor tissues of patients with CRC were collected to evaluate TIM3 expression using flow cytometry. Cytokines in the serum of healthy donors and patients with early- and advanced-stage CRC were screened using a multiplex assay. The effects of interleukin-8 (IL8) on TIM3 expression on CD8+ T cells were analyzed using cell incubation experiments in vitro. The correlation between TIM3 or IL8 and prognosis was verified using bioinformatics analysis. RESULTS: TIM3 expression on CD8+ T cells was obviously reduced in patients with advanced-stage CRC, whereas a lower TIM3 expression level was associated with poorer prognosis. Macrophage-derived IL8, which could inhibit TIM3 expression on CD8+ T cells, was significantly increased in the serum of patients with advanced CRC. In addition, the function and proliferation of CD8+ and TIM3+CD8+ T cells were inhibited by IL8, which was partly depending on TIM3 expression. The inhibitory effects of IL8 were reversed by anti-IL8 and anti-CXCR2 antibodies. CONCLUSIONS: In summary, macrophages-derived IL8 suppresses TIM3 expression on CD8+ T cells through CXCR2. Targeting the IL8/CXCR2 axis may be an effective strategy for treating patients with advanced CRC.

Mechanism and strategies of immunotherapy resistance in colorectal cancer.

Colorectal cancer (CRC) is the third most common cancer in the world. Although there are standard treatment options for CRC, most patients respond poorly to these treatments. Immunotherapies have gradually emerged due to the increasing awareness and understanding of tumor immunity, exhibiting good therapeutic efficacy in various cancers. Immunotherapies include cytokines, immune checkpoint inhibitors (ICIs), and adoptive cell therapies. In particular, ICIs, which are antibodies against cytotoxic T lymphocyte-associated protein 4 (CTLA-4), programmed cell death 1 (PD-1), or its ligand PD-L1, have been successfully applied clinically for solid tumors, relieving the inhibitory effect of the tumor microenvironment on T cells. However, only a minority of patients with cancer achieve a durable clinical response during immunotherapy. Several factors restrict the efficacy of immunotherapy, leading to the development of drug resistance. In this review, we aimed to discuss the current status of immunotherapy for CRC and elaborate on the mechanisms that mediate resistance to immunotherapy and other potential therapeutic strategies.

Long-term clinical efficacy of cytokine-induced killer cell-based immunotherapy in early-stage esophageal squamous cell carcinoma.

BACKGROUND AIMS: In this retrospective clinical study, the authors investigated the impact of cytokine-induced killer (CIK) cell-based immunotherapies on the long-term survival of patients with esophageal squamous cell carcinoma (ESCC). METHODS: A total of 87 patients with ESCC who received comprehensive treatment were enrolled in the study. Of these patients, 43 were in the control group and 44 were in the CIK treatment group. Flow cytometry analysis was performed to detect the phenotype and anti-tumor function of CIK cells. Clinical characteristics were compared between these two groups, and the survival estimates of ESCC patients were determined using Kaplan-Meier analysis. RESULTS: CIK cells contained a high proportion of the main functional fraction (CD3+CD56+ group) and exhibited a strong killing ability for esophageal cancer cells in vitro. Importantly, overall survival (OS) and progression-free survival (PFS) were significantly higher in the CIK group than in the control group in early-stage ESCC. However, patients with advanced-stage ESCC did not benefit from CIK cell-based therapy in terms of OS and PFS compared with the control group. CONCLUSIONS: These results demonstrate that CIK cells combined with conventional treatments potentially prolong long-term survival of patients and may serve as a combined therapeutic approach for the treatment of early-stage ESCC.

Contradictory roles of lipid metabolism in immune response within the tumor microenvironment.

Complex interactions between the immune system and tumor cells exist throughout the initiation and development of cancer. Although the immune system eliminates malignantly transformed cells in the early stage, surviving tumor cells evade host immune defense through various methods and even reprogram the anti-tumor immune response to a pro-tumor phenotype to obtain unlimited growth and metastasis. The high proliferation rate of tumor cells increases the demand for local nutrients and oxygen. Poorly organized vessels can barely satisfy this requirement, which results in an acidic, hypoxic, and glucose-deficient tumor microenvironment. As a result, lipids in the tumor microenvironment are activated and utilized as a primary source of energy and critical regulators in both tumor cells and related immune cells. However, the exact role of lipid metabolism reprogramming in tumor immune response remains unclear. A comprehensive understanding of lipid metabolism dysfunction in the tumor microenvironment and its dual effects on the immune response is critical for mapping the detailed landscape of tumor immunology and developing specific treatments for cancer patients. In this review, we have focused on the dysregulation of lipid metabolism in the tumor microenvironment and have discussed its contradictory roles in the tumor immune response. In addition, we have summarized the current therapeutic strategies targeting lipid metabolism in tumor immunotherapy. This review provides a comprehensive summary of lipid metabolism in the tumor immune response.

Identification and characterization of prognosis-related genes in the tumor microenvironment of esophageal squamous cell carcinoma.

BACKGROUND: Esophageal squamous cell carcinoma (ESCC) is the main pathological subtype of esophageal cancer with high incidence and mortality. Immune and stromal cells in the tumor microenvironment (TME) profoundly affect the development of ESCC. METHODS: In this study, we used the ESTIMATE algorithm to calculate the immune and stromal scores of ESCC samples in The Cancer Genome Atlas (TCGA) database. Next, we used the R package limma to identify differentially expressed genes (DEGs) from high- versus low-immune/stromal score groups and these DEGs were further utilized to analyze the functional annotations, protein-protein interaction (PPI) networks and overall survival of patients with ESCC. Finally, we identified the biological roles of core gene C3AR1 in the TME of ESCC using the TCGA database and in vitro experiments. RESULTS: We obtained the immune and stromal scores of ESCC samples and further evaluated the impact of these scores on the prognosis and clinical parameters of patients with ESCC. Next, we identified 410 DEGs from high- versus low-immune/stromal score groups and to gain better understanding of the biological functions and characteristics of DEGs. Among these DEGs, 69 were correlated with the overall survival of patients with ESCC and C3AR1 was identified as a core gene for the regulation of most genes in the network. We found that C3AR1 was positively correlated with M2 macrophages and immune inhibitory molecules (T-cell immunoglobulin and mucin domain 3 (TIM-3), programmed cell death-1 (PD-1)), but not with M1 macrophages. We also observed a higher expression of CD163 and CD206, which were the markers for M2 macrophages in the TLQP-21 TFA (the agonist of C3AR1)groups than in the control groups. CONCLUSION: Based on the ESTIMATE algorithm, we obtained and characterized prognosis-related genes in the TME of ESCC samples from the TCGA database. We have further revealed that C3AR1 may cause an immunosuppressive microenvironment by affecting the polarization of macrophages to M2 phenotype and lead to the progression of ESCC, which indicates that C3AR1 may be a potential target for immunotherapy.

Identification of Key Pathways and Genes Related to Immunotherapy Resistance of LUAD Based on WGCNA Analysis.

Immunotherapy resistance is a major barrier in the application of immune checkpoint inhibitors (ICI) in lung adenocarcinoma (LUAD) patients. Although recent studies have found several mechanisms and potential genes responsible for immunotherapy resistance, ways to solve this problem are still lacking. Tumor immune dysfunction and exclusion (TIDE) algorithm is a newly developed method to calculate potential regulators and indicators of ICI resistance. In this article, we combined TIDE and weighted gene co-expression network analysis (WGCNA) to screen potential modules and hub genes that are highly associated with immunotherapy resistance using the Cancer Genome Atlas (TCGA) dataset of LUAD patients. We identified 45 gene co-expression modules, and the pink module was most correlated with TIDE score and other immunosuppressive features. After considering the potential factors in immunotherapy resistance, we found that the pink module was also highly related to cancer stemness. Further analysis showed enriched immunosuppressive cells in the extracellular matrix (ECM), immunotherapy resistance indicators, and common cancer-related signaling pathways in the pink module. Seven hub genes in the pink module were shown to be significantly upregulated in tumor tissues compared with normal lung tissue, and were related to poor survival of LUAD patients. Among them, THY1 was the gene most associated with TIDE score, a gene highly related to suppressive immune states, and was shown to be strongly expressed in late-stage patients. Immunohistochemistry (IHC) results demonstrated that THY1 level was higher in the progressive disease (PD) group of LUAD patients receiving a PD-1 monoclonal antibody (mAb) and positively correlated with SOX9. Collectively, we identified that THY1 could be a critical biomarker in predicting ICI efficiency and a potential target for avoiding tumor immunotherapy resistance.

Resistance Mechanisms of Anti-PD1/PDL1 Therapy in Solid Tumors.

In cancer-immunity cycle, the immune checkpoint PD1 and its ligand PDL1 act as accomplices to help tumors resist to immunity-induced apoptosis and promote tumor progression. Immunotherapy targeting PD1/PDL1 axis can effectively block its pro-tumor activity. Anti-PD1/PDL1 therapy has achieved great success in the past decade. However, only a subset of patients showed clinical responses. Most of the patients can not benefit from anti-PD1/PDL1 therapy. Furthermore, a large group of responders would develop acquired resistance after initial responses. Therefore, understanding the mechanisms of resistance is necessary for improving anti-PD1/PDL1 efficacy. Currently, researchers have identified primary resistance mechanisms which include insufficient tumor immunogenicity, disfunction of MHCs, irreversible T cell exhaustion, primary resistance to IFN-γ signaling, and immunosuppressive microenvironment. Some oncogenic signaling pathways also contribute to the primary resistance. Under the pressure applied by anti-PD1/PDL1 therapy, tumors experience immunoediting and preserve beneficial mutations, upregulate the compensatory inhibitory signaling and induce re-exhaustion of T cells, all of which may attenuate the durability of the therapy. Here we explore the underlying mechanisms in detail, review biomarkers that help identifying responders among patients and discuss the strategies that may relieve the anti-PD1/PDL1 resistance.

Tumor-intrinsic signaling pathways: key roles in the regulation of the immunosuppressive tumor microenvironment.

Immunotherapy is a currently popular treatment strategy for cancer patients. Although recent developments in cancer immunotherapy have had significant clinical impact, only a subset of patients exhibits clinical response. Therefore, understanding the molecular mechanisms of immunotherapy resistance is necessary. The mechanisms of immune escape appear to consist of two distinct tumor characteristics: a decrease in effective immunocyte infiltration and function and the accumulation of immunosuppressive cells in the tumor microenvironment. Several host-derived factors may also contribute to immune escape. Moreover, inter-patient heterogeneity predominantly results from differences in somatic mutations between cancers, which has led to the hypothesis that differential activation of specific tumor-intrinsic pathways may explain the phenomenon of immune exclusion in a subset of cancers. Increasing evidence has also shown that tumor-intrinsic signaling plays a key role in regulating the immunosuppressive tumor microenvironment and tumor immune escape. Therefore, understanding the mechanisms underlying immune avoidance mediated by tumor-intrinsic signaling may help identify new therapeutic targets for expanding the efficacy of cancer immunotherapies.

IL-10 derived from M2 macrophage promotes cancer stemness via JAK1/STAT1/NF-κB/Notch1 pathway in non-small cell lung cancer.

Tumor-associated macrophages (TAMs), key immune cells in the tumor microenvironment, are shown to be closely correlated with the progression of non-small cell lung cancer (NSCLC). Cancer stem cells (CSCs) can contribute to NSCLC progression as well. We aimed to clarify whether TAMs promote the progression of NSCLC by mainly affecting the activities of CSCs. We found that TAM-like cells promoted CSC-like properties in NSCLC cells in vitro, which was mediated by TAM-derived IL-10. TAM-derived IL-10 promoted CSC-like properties of NSCLC cells through JAK1/STAT1/NF-κB/Notch1 signaling. Blockade of IL-10/JAK1 signaling inhibited TAM-mediated NSCLC tumor growth in vivo, and the TAM-mediated expression of CSC-related and mesenchymal-related genes in NSCLC. Lastly, expression levels of these signaling molecules were significantly correlated with survival of NSCLC patients. Therefore, IL-10/JAK1 signaling might be a potential therapeutic target for NSCLC treatment.