Single-cell transcriptomics reveal distinct immune-infiltrating phenotypes and macrophage-tumor interaction axes among different lineages of pituitary neuroendocrine tumors

BACKGROUND

Pituitary neuroendocrine tumors (PitNETs) are common gland neoplasms demonstrating distinctive transcription factors. Although the role of immune cells in PitNETs has been widely recognized, the precise immunological environment and its control over tumor cells are poorly understood.

METHODS

The heterogeneity, spatial distribution, and clinical significance of macrophages in PitNETs were analyzed using single-cell RNA sequencing (scRNA-seq), bulk RNA-seq, spatial transcriptomics, immunohistochemistry, and multiplexed quantitative immunofluorescence (QIF). Cell viability, cell apoptosis assays, and in vivo subcutaneous xenograft experiments have confirmed that INHBA-ACVR1B influences the process of tumor cell apoptosis.

RESULTS

The present study evaluated scRNA-seq data from 23 PitNET samples categorized into 3 primary lineages. The objective was to explore the diversity of tumors and the composition of immune cells across these lineages. Analyzed data from scRNA-seq and 365 bulk RNA sequencing samples conducted in-house revealed the presence of three unique subtypes of tumor immune microenvironment (TIME) in PitNETs. These subtypes were characterized by varying levels of immune infiltration, ranging from low to intermediate to high. In addition, the NR5A1 lineage is primarily associated with the subtype characterized by limited infiltration of immune cells. Tumor-associated macrophages (TAMs) expressing CX3CR1+, C1Q+, and GPNMB+ showed enhanced contact with tumor cells expressing NR5A1 + , TBX19+, and POU1F1+, respectively. This emphasizes the distinct interaction axes between TAMs and tumor cells based on their lineage. Moreover, the connection between CX3CR1+ macrophages and tumor cells via INHBA-ACVR1B regulates tumor cell apoptosis.

CONCLUSIONS

In summary, the different subtypes of TIME and the interaction between TAM and tumor cells offer valuable insights into the control of TIME that affects the development of PitNET. These findings can be utilized as prospective targets for therapeutic interventions.

Chemotherapy-elicited extracellular vesicle CXCL1 from dying cells promotes triple-negative breast cancer metastasis by activating TAM/PD-L1 signaling

BACKGROUND

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, and chemotherapy still serves as the cornerstone treatment functioning by inducing cytotoxic cell death. Notably, emerging evidence suggests that dying cell-released signals may induce cancer progression and metastasis by modulating the surrounding microenvironment. However, the underlying molecular mechanisms and targeting strategies are yet to be explored.

METHODS

Apoptotic TNBC cells induced by paclitaxel or adriamycin treatment were sorted and their released extracellular vesicles (EV-dead) were isolated from the cell supernatants. Chemokine array analysis was conducted to identify the crucial molecules in EV-dead. Zebrafish and mouse xenograft models were used to investigate the effect of EV-dead on TNBC progression in vivo.

RESULTS

It was demonstrated that EV-dead were phagocytized by macrophages and induced TNBC metastasis by promoting the infiltration of immunosuppressive PD-L1+ TAMs. Chemokine array identified CXCL1 as a crucial component in EV-dead to activate TAM/PD-L1 signaling. CXCL1 knockdown in EV-dead or macrophage depletion significantly inhibited EV-dead-induced TNBC growth and metastasis. Mechanistic investigations revealed that CXCL1EV-dead enhanced TAM/PD-L1 signaling by transcriptionally activating EED-mediated PD-L1 promoter activity. More importantly, TPCA-1 (2-[(aminocarbonyl) amino]-5-(4-fluorophenyl)-3-thiophenecarboxamide) was screened as a promising inhibitor targeting CXCL1 signals in EVs to enhance paclitaxel chemosensitivity and limit TNBC metastasis without noticeable toxicities.

CONCLUSIONS

Our results highlight CXCL1EV-dead as a novel dying cell-released signal and provide TPCA-1 as a targeting candidate to improve TNBC prognosis.

Novel T cell exhaustion gene signature to predict prognosis and immunotherapy response in thyroid carcinoma from integrated RNA-sequencing analysis

Exhausted CD8+ T lymphocytes and tumor-associated macrophages play critical roles in determining cancer prognosis and the efficacy of immunotherapy. Our study revealed a negative correlation between exhausted CD8+ T lymphocytes and prognosis in thyroid carcinoma (THCA). Consensus clustering divided patients into two subgroups of exhaustion with different prognoses, as defined by marker genes of exhausted CD8+ T cells. Subsequently, we constructed an eight-gene prognostic signature, and developed a risk score named the exhaustion-related gene score (ERGS) to forecast both prognosis and immunotherapy response in THCA. Bulk RNA sequencing analysis revealed a higher prevalence of M2 macrophages, indicative of an immunosuppressive tumor microenvironment (TME), in the high-ERGS group. Single-cell RNA sequencing showed that SPP1+ macrophages and CD14+ monocytes infiltrations were positively associated with higher ERGS. Functionally, it was determined that SPP1+ macrophages exert an immunosuppressive role, while CD14+ monocytes were implicated in promoting tumor progression and angiogenesis. Analysis of cell-cell interactions between SPP1+ macrophages and T cells highlighted the activation of the SPP1-CD44 and MIF-CD74 axes, both of which could foster an immunosuppressive TME. Therapeutic strategies that target SPP1+ macrophages, CD14+ monocytes, and the SPP1-CD44 and MIF-CD74 axes may potentially improve the prognosis and amplify the immunotherapy response in THCA patients.

Myostatin expression in lung cancer induces sarcopenia and promotes cancer progression

OBJECTIVES

Many studies have demonstrated that sarcopenia among lung cancer predicts poor prognosis due to cancer progression. However, the cytokines that link sarcopenia and lung cancer progression remain unidentified. This study aimed to investigate whether lung cancer producing myostatin, which induces skeletal muscle atrophy, leads to sarcopenia and promotes cancer progression in patients with resected lung cancer.

METHODS

Tumor tissues were obtained from 148 patients who underwent curative resection for lung cancer. Tumor cells were stained with myostatin and tumor-associated macrophages (TAM) in the tumor microenvironment were stained with CD68. We assessed the association between myostatin expression and the clinicopathological features.

RESULTS

High myostatin expression in lung cancer was significantly associated with low skeletal muscle mass. The 5-year overall survival and relapse-free survival were significantly worse among patients with high myostatin expression than those with low expression. A multivariate analysis showed that TAM count was positively correlated with high myostatin expression.

CONCLUSION

Sarcopenia may be induced by myostatin secreted by lung cancer cells. Moreover, myostatin may promote TAM migration into the tumor microenvironment, leading to advance lung cancer. As a result, patients with high myostatin expression had poor prognosis.

Arginine-assembly as NO nano-donor prevents the negative feedback of macrophage repolarization by mitochondrial dysfunction for cancer immunotherapy

Repolarizing the tumor-associated macrophages (TAMs) towards the antitumoral M1-like phenotype has been a promising approach for cancer immunotherapy. However, the anti-cancer immune response is severely limited mainly by the repolarized M1-like macrophages belatedly returning to the M2-like phenotype (i.e., negative feedback). Inspired by nitric oxide (NO) effectively preventing repolarization of inflammatory macrophages in inflammatory diseases, herein, we develop an arginine assembly, as NO nano-donor for NO generation to prevent the negative feedback of the macrophage repolarization. The strategy is to first apply reversible tagging of hydrophobic terephthalaldehyde to create an arginine nano-assembly, and then load a toll-like receptor 7/8 agonist resiquimod (R848) (R848@Arg). Through this strategy, a high loading efficiency of 40 % for the arginine and repolarization characteristics for TAMs can be achieved. Upon the macrophage repolarization by R848, NO can be intracellularly generated from the released arginine by the upregulated inducible nitric oxide synthase. Mechanistically, NO effectively prevented the negative feedback of the repolarized macrophage by mitochondrial dysfunction via blocking oxidative phosphorylation. Notably, R848@Arg significantly increased the tumor inhibition ratio by 3.13-fold as compared to the free R848 by maintaining the M1-like phenotype infiltrating into tumor. The Arg-assembly as NO nano-donor provides a promising method for effective repolarization of macrophages.

In vivo visualization of tumor-associated macrophages re-education by photoacoustic/fluorescence dual-modal imaging with a metal-organic frames-based caspase-1 nanoreporter

Tumor-associated macrophages (TAMs) are vital in the tumor microenvironment, contributing to immunosuppression and therapy tolerance. Despite their importance, the precise re-education of TAMs in vivo continues to present a formidable challenge. Moreover, the lack of real-time and efficient methods to comprehend the spatiotemporal kinetics of TAMs repolarization remains a significant hurdle, severely hampering the accurate assessment of treatment efficacy and prognosis. Herein, we designed a metal-organic frameworks (MOFs) based Caspase-1 nanoreporter (MCNR) that can deliver a TLR7/8 agonist to the TAMs and track time-sensitive Caspase-1 activity as a direct method to monitor the initiation of immune reprogramming. This nanosystem exhibits excellent TAMs targeting ability, enhanced tumor accumulation, and stimuli-responsive behavior. By inducing the reprogramming of TAMs, they were able to enhance T-cell infiltration in tumor tissue, resulting in inhibited tumor growth and improved survival in mice model. Moreover, MCNR also serves as an activatable photoacoustic and fluorescent dual-mode imaging agent through Caspase-1-mediated specific enzyme digestion. This feature enables non-invasive and real-time antitumor immune activation monitoring. Overall, our findings indicate that MCNR has the potential to be a valuable tool for tumor immune microenvironment remodeling and noninvasive quantitative detection and real-time monitoring of TAMs repolarization to immunotherapy in the early stage.

[Tumor-associated Macrophage: Emerging Targets for Modulating the Tumor Microenvironment]

Tumor-associated macrophage (TAM) play a crucial role in the immune microenvironment of lung cancer. Through changes in their phenotype and phagocytic functions, TAM contribute to the initiation and progression of lung cancer. By promoting the formation of an immune-suppressive microenvironment and accelerating the growth of abnormal tumor vasculature, TAM facilitate the invasion and metastasis of lung cancer. Macrophages can polarize into different subtypes with distinct functions and characteristics in response to various stimuli, categorized as anti-tumor M1 and pro-tumor M2 types. In tumor tissues, TAM typically polarize into the alternatively activated M2 phenotype, exhibiting inhibitory effects on tumor immunity. This article reviews the role of anti-angiogenic drugs in modulating TAM phenotypes, highlighting their potential to reprogram M2-type TAM into an anti-tumor M1 phenotype. Additionally, the functional alterations of TAM play a significant role in anti-angiogenic therapy and immunotherapy strategies. In summary, the regulation of TAM polarization and function opens up new avenues for lung cancer treatment and may serve as a novel target for modulating the immune microenvironment of tumors.
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Involvement of CX3CR1+ cells appearing in the abdominal cavity in the immunosuppressive environment immediately after gastric cancer surgery

BACKGROUND

Gastric cancer is primarily treated by surgery; however, little is known about the changes in the intraperitoneal immune environment and the prognostic impact of surgery. Surgical stress and cancer-associated inflammation cause immune cells to mobilize into the abdominal cavity via numerous cytokines. One such cytokine, CX3CR1, has various immune-related functions that remain to be fully explained. We characterized the intraperitoneal immune environment by investigating CX3CR1+ cells in intraperitoneal lavage fluid during gastric cancer surgery.

METHODS

Lavage fluid samples were obtained from a total of 41 patients who underwent gastrectomy. The relative expression of various genes was analyzed using quantitative real-time PCR. The association of each gene expression with clinicopathological features and surgical outcomes was examined. The fraction of CX3CR1+ cells was analyzed by flow cytometry. Cytokine profiles in lavage fluid samples were investigated using a cytometric beads array.

RESULTS

CX3CR1high patients exhibited higher levels of perioperative inflammation in blood tests and more recurrences than CX3CR1low patients. CX3CR1high patients tended to exhibit higher pathological T and N stage than CX3CR1low patients. CX3CR1 was primarily expressed on myeloid-derived suppressor cells and tumor-associated macrophages. In particular, polymorphonuclear myeloid-derived suppressor cells were associated with perioperative inflammation, pathological N, and recurrences. These immunosuppressive cells were associated with a trend toward unfavorable prognosis. Moreover, CX3CR1 expression was correlated with programmed death-1 expression.

CONCLUSIONS

Our results suggest that CX3CR1+ cells are associated with an acute inflammatory response, tumor-promotion, and recurrence. CX3CR1 expression could be taken advantage of as a beneficial therapeutic target for improving immunosuppressive state in the future. In addition, analysis of intra-abdominal CX3CR1+ cells could be useful for characterizing the immune environment after gastric cancer surgery.

LncRNA-HOXC-AS2 regulates tumor-associated macrophage polarization through the STAT1/SOCS1 and STAT1/CIITA pathways to promote the progression of non-small cell lung cancer

Tumor-associated macrophages (TAMs) mainly exhibit the characteristics of M2-type macrophages, and the regulation of TAM polarization is a new target for cancer therapy, among which lncRNAs are key regulatory molecules. This study aimed to explore the effects of lncRNA-HOXC-AS2 on non-small cell lung cancer (NSCLC) by regulating TAM polarization. THP-1 cells were used to differentiate into macrophages, and TAMs were obtained by coculture with A549 cells. The M1/M2 cell phenotype and HOXC-AS2 expression were detected, and A549-derived exosomes (A549-exo) were used to elucidate the effects of A549 on macrophage polarization and HOXC-AS2 expression. Then, by interfering with HOXC-AS2 or STAT1, the effects of HOXC-AS2 regulation of STAT1 on the TAM phenotype and STAT1/SOCS1 and STAT1/CIITA pathways were analyzed, and the proliferation and metastasis of NSCLC cells in the coculture system were also detected. Results showed that HOXC-AS2 expression in M2 macrophages and TAMs was significantly higher than that in M1 macrophages, and A549-exo promoted HOXC-AS2 expression and M2 polarization. Intervention HOXC-AS2 resulted in increased M1 marker expression, decreased M2 marker expression, and activation of STAT1/SOCS1 and STAT1/CIITA pathways in TAMs. In addition, HOXC-AS2 was mainly expressed in the cytoplasm of TAMs and could bind to STAT1. Further experiments confirmed that intervention HOXC-AS2 promoted the M1 polarization of TAMs by targeting STAT1 and weakened the promoting effects of TAMs on the proliferation and metastasis of NSCLC. In conclusion, HOXC-AS2 inhibited the activation of STAT1/SOCS1 and STAT1/CIITA pathways and promoted M2 polarization of TAMs by binding with STAT1, thus promoting NSCLC.

Targeting lipid metabolism of macrophages: A new strategy for tumor therapy

BACKGROUND

Lipid metabolism has been implicated in a variety of normal cellular processes and strongly related to the development of multiple diseases, including tumor. Tumor-associated macrophage (TAM) has emerged as a crucial regulator in tumorigenesis and promising target for tumor treatment.

AIM OF REVIEW

A thorough understanding of TAM lipid metabolism and its value in tumorigenesis may provide new ideas for TAM-based anti-tumor therapy. Key scientific concepts of review: TAMs can be divided into two main types, M1-like TAMs and M2-like TAMs, which play anti-tumor and pro-tumor functions in tumor occurrence and development, respectively. Accumulating evidence has shown that lipid metabolic reprogramming, including fatty acid uptake and utilization, cholesterol expulsion, controls the polarization of TAMs and affects the tumorgenesis. These advances in uncovering the intricacies of lipid metabolism and TAMs have yielded new insights on tumor development and treatment. In this review, we aim to provide an update on the current understanding of the lipid metabolic reprogramming made by TAMs to adapt to the harsh tumor microenvironment (TME). In particular, we emphasize that there is complex lipid metabolism connections between TAMs and distinct tumors, which influences TAM to bias from M1 to M2 phenotype in tumor progression, and ultimately promotes tumor occurrence and development. Finally, we discuss the existing issues on therapeutic strategies by reprogramming TAMs based on lipid metabolism regulation (or increasing the ratio of M1/M2-like TAMs) that could be applied in the future to clinical tumor treatment.

Targeting metabolic sensing switch GPR84 on macrophages for cancer immunotherapy

INTRODUCTION

As one of the major components of the tumor microenvironment, tumor-associated macrophages (TAMs) possess profound inhibitory activity against T cells and facilitate tumor escape from immune checkpoint blockade therapy. Converting this pro-tumorigenic toward the anti-tumorigenic phenotype thus is an important strategy for enhancing adaptive immunity against cancer. However, a plethora of mechanisms have been described for pro-tumorigenic differentiation in cancer, metabolic switches to program the anti-tumorigenic property of TAMs are elusive.

MATERIALS AND METHODS

From an unbiased analysis of single-cell transcriptome data from multiple tumor models, we discovered that anti-tumorigenic TAMs uniquely express elevated levels of a specific fatty acid receptor, G-protein-coupled receptor 84 (GPR84). Genetic ablation of GPR84 in mice leads to impaired pro-inflammatory polarization of macrophages, while enhancing their anti-inflammatory phenotype. By contrast, GPR84 activation by its agonist, 6-n-octylaminouracil (6-OAU), potentiates pro-inflammatory phenotype via the enhanced STAT1 pathway. Moreover, 6-OAU treatment significantly retards tumor growth and increases the anti-tumor efficacy of anti-PD-1 therapy.

CONCLUSION

Overall, we report a previously unappreciated fatty acid receptor, GPR84, that serves as an important metabolic sensing switch for orchestrating anti-tumorigenic macrophage polarization. Pharmacological agonists of GPR84 hold promise to reshape and reverse the immunosuppressive TME, and thereby restore responsiveness of cancer to overcome resistance to immune checkpoint blockade.

Identification macrophage signatures in prostate cancer by single-cell sequencing and machine learning

BACKGROUND

The tumor microenvironment (TME) encompasses a variety of cells that influence immune responses and tumor growth, with tumor-associated macrophages (TAM) being a crucial component of the TME. TAM can guide prostate cancer in different directions in response to various external stimuli.

METHODS

First, we downloaded prostate cancer single-cell sequencing data and second-generation sequencing data from multiple public databases. From these data, we identified characteristic genes associated with TAM clusters. We then employed machine learning techniques to select the most accurate TAM gene set and developed a TAM-related risk label for prostate cancer. We analyzed the tumor-relatedness of the TAM-related risk label and different risk groups within the population. Finally, we validated the accuracy of the prognostic label using single-cell sequencing data, qPCR, and WB assays, among other methods.

RESULTS

In this study, the TAM_2 cell cluster has been identified as promoting the progression of prostate cancer, possibly representing M2 macrophages. The 9 TAM feature genes selected through ten machine learning methods and demonstrated their effectiveness in predicting the progression of prostate cancer patients. Additionally, we have linked these TAM feature genes to clinical pathological characteristics, allowing us to construct a nomogram. This nomogram provides clinical practitioners with a quantitative tool for assessing the prognosis of prostate cancer patients.

CONCLUSION

This study has analyzed the potential relationship between TAM and PCa and established a TAM-related prognostic model. It holds promise as a valuable tool for the management and treatment of PCa patients.

C-C chemokine receptor 4 (CCR4)-positive regulatory T cells interact with tumor-associated macrophages to facilitate metastatic potential after radiation

PURPOSE

Our previous study revealed that elevated C-C motif chemokine ligand 2 (CCL2) secretion by irradiated cancer cells recruited C-C motif chemokine receptor 2 (CCR2)-positive myeloid cells and polarized M2-type tumor-associated macrophages (TAMs), promoting lung metastasis in an established mouse model. This study investigated the impact of CCL2 and TAMs on adaptive immunity.

METHODS

We assessed the influence of CCL2 and TAMs on adaptive immunity through two ectopic allograft mouse models constructed with MB49 bladder cancer cells and Lewis lung carcinoma cells. Both models exhibited delayed primary tumor growth following radiation therapy (RT), but RT promoted the development of pulmonary metastases in C57BL/6 mice. Additionally, we employed a direct coculture system to investigate the interaction between macrophages and target cells in the context of adaptive immunity.

RESULTS

C-C motif chemokine receptor 4 (CCR4)-positive regulatory T cells (Tregs) were recruited to the postirradiated tumor microenvironment (TME). Utilizing a CCR4 antagonist to inhibit CCL2-CCR4 activation reversed the infiltration of CCR4 + Tregs and reduced the incidence of pulmonary metastases. In addition, a positive feedback loop between M2-type TAMs and Tregs was observed. The combined blockade of the CCL2-CCR4 and CCL2-CCR2 signaling pathways further decreased the risk of RT-promoted lung metastasis.

CONCLUSION

The recruitment of CCR4 + Tregs to the postirradiated TME increases the metastatic potential of tumor cells through increased interactions with M2-type TAMs. A significant reduction in post-RT lung metastases in ectopic mouse models was achieved by disrupting the recruitment of both CCR4 + Tregs and CCR2 + myeloid cells, which are TAM precursors.

Integrating single-cell and bulk RNA sequencing reveals CK19 + cancer stem cells and their specific SPP1 + tumor-associated macrophage niche in HBV-related hepatocellular carcinoma

PURPOSE

Cytokeratin 19-positive cancer stem cells (CK19 + CSCs) and their tumor-associated macrophages (TAMs) have not been fully explored yet in the hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC).

EXPERIMENTAL DESIGN

Single-cell RNA sequencing was performed on the viable cells obtained from 11 treatment-naïve HBV-associated HCC patients, including 8 CK19 + patients, to elucidate their transcriptomic landscape, CK19 + CSC heterogeneity, and immune microenvironment. Two in-house primary HCC cohorts (96 cases-related HBV and 89 cases with recurrence), TCGA external cohort, and in vitro and in vivo experiments were used to validate the results.

RESULTS

A total of 64,581 single cells derived from the human HCC and adjacent normal tissues were sequenced, and 11 cell types were identified. The result showed that CK19 + CSCs were phenotypically and transcriptionally heterogeneous, co-expressed multiple hepatics CSC markers, and were positively correlated with worse prognosis. Moreover, the SPP1 + TAMs (TAM_SPP1) with strong M2-like features and worse prognosis were specifically enriched in the CK19 + HCC and promoted tumor invasion and metastasis by activating angiogenesis. Importantly, matrix metalloproteinase 9 (MMP9) derived from TAM_SPP1, as the hub gene of CK19 + HCC, was activated by the VEGFA signal.

CONCLUSIONS

This study revealed the heterogeneity and stemness characteristics of CK19 + CSCs and specific immunosuppressive TAM_SPP1 in CK19 + HCC. The VEGFA signal can activate TAM_SPP1-derived MMP9 to promote the invasion and metastasis of CK19 + HCC tumors. This might provide novel insights into the clinical treatment of HCC patients.

RNA-based modulation of macrophage-mediated efferocytosis potentiates antitumor immunity in colorectal cancer

Tumor-associated macrophages play pivotal roles in tumor progression and metastasis. Macrophage-mediated clearance of apoptotic cells (efferocytosis) supports inflammation resolution, contributing to immune evasion in colorectal cancers. To reverse this immunosuppressive process, we propose a readily translatable RNA therapy to selectively inhibit macrophage-mediated efferocytosis in tumor microenvironment. A clinically approved lipid nanoparticle platform (LNP) is employed to encapsulate siRNA for the phagocytic receptor MerTK (siMerTK), enabling selective MerTK inhibition in the diseased organ. Decreased MerTK expression in tumor-associated macrophages results in apoptotic cell accumulation and immune activation in tumor microenvironment, leading to suppressed tumor growth and better survival in both liver and peritoneal metastasis models of colorectal cancers. siMerTK delivery combined with PD-1 blockade further produces enhanced antimetastatic efficacy with reactivated intratumoral immune milieu. Collectively, LNP-based siMerTK delivery combined with immune checkpoint therapy may present a feasible modality for metastatic colorectal cancer therapy.

CD204-positive M2-like tumor-associated macrophages increase migration of gastric cancer cells by upregulating miR-210 to reduce NTN4 expression

BACKGROUND

Tumor-associated macrophages (TAMs) are the predominant immune cells in the tumor microenvironment and portend poor prognosis. However, the molecular mechanisms underlying the tumor promotion of TAMs have not been fully elucidated.

METHODS

Coculture of gastric cancer cells with U937 cells was performed to investigate the impact of TAMs on cancer cell behavior. MicroRNA (miRNA) microarray and bioinformatics were applied to identify the involved miRNAs and the functional target genes. The regulation of the miRNA on its target gene was studied using anti-miRNA and miRNA mimic.

RESULTS

Coculture with CD204+ M2-like TAMs increased proliferation, migration, and epithelial-mesenchymal transition of gastric cancer cells. MiR-210 was the most upregulated miRNA in cancer cells identified by miRNA microarray after coculture. In gastric cancer tissues, miR-210 expression was positively correlated with CD204+ M2-like TAM infiltration. Inactivation of miR-210 by antimir attenuated CD204+ M2-like TAMs-induced cancer cell migration. Using pharmacological inhibitors and neutralizing antibodies, CD204+ M2-like TAMs-secreted TNFα was found to upregulate miR-210 through NF-κB/HIF-1α signaling. Bioinformatics analysis showed netrin-4 (NTN4) as a potential target of miR-210 to suppress gastric cancer cell migration. We also found an inverse expression between miR-210 and NTN4 in cancer cells after coculture or in tumor xenografts. Anti-miR-210 increased NTN4 expression, while miR-210 mimics downregulated NTN4 in cancer cells. Reporter luciferase assays showed that MiR-210 mimics suppressed NTN4 3' untranslated region-driven luciferase activity in cancer cells, but this effect was blocked after mutating miR-210 binding site.

CONCLUSIONS

CD204+ M2-like TAMs can utilize the TNF-α/NF-κB/HIF-1α/miR-210/NTN4 pathway to facilitate gastric cancer progression.

SILAC proteomics based on 3D cell spheroids unveils the role of RAC2 in regulating the crosstalk between triple-negative breast cancer cells and tumor-associated macrophages

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, and is characterized by a high infiltration of tumor-associated macrophages (TAMs). TAMs contribute significantly to tumor progression by intricately interacting with tumor cells. Deeply investigating the interaction between TNBC cells and TAMs is of great importance for finding potential biomarkers and developing novel therapeutic strategies to further improve the clinical outcomes of TNBC patients. In this study, we confirmed the interplay using both 3D and 2D co-culture models. The stable-isotype labeling by amino acids in cell culture (SILAC)-based quantitative proteomics was conducted on 3D cell spheroids containing TNBC cells and macrophages to identify the potential candidate in regulating the crosstalk between TNBC and TAMs. Ras-related C3 botulinum toxin substrate 2 (RAC2) was identified as a potential molecule for further exploration, given its high expression in TNBC and positive correlation with M2 macrophage infiltration. The suppression of RAC2 inhibited TNBC cell proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) in vitro. Meanwhile, knocking down RAC2 in TNBC cells impaired macrophage recruitment and M2 polarization. Mechanistically, RAC2 exerted its roles in TNBC cells and TAMs by regulating the activation of P65 NF-κB and P38 MAPK, while TAMs further elevated RAC2 expression and P65 NF-κB activation by secreting soluble mediators including IL-10. These findings highlight the significance of RAC2 as a crucial molecule in the crosstalk between TNBC and TAMs, suggesting it could be a promising therapeutic target in TNBC.

Engineering TGF-β inhibitor-encapsulated macrophage-inspired multi-functional nanoparticles for combination cancer immunotherapy

BACKGROUND

The emergence of cancer immunotherapies, notably immune checkpoint inhibitors, has revolutionized anti-cancer treatments. These treatments, however, have been reported to be effective in a limited range of cancers and cause immune-related adverse effects. Thus, for a broader applicability and enhanced responsiveness to solid tumor immunotherapy, immunomodulation of the tumor microenvironment is crucial. Transforming growth factor-β (TGF-β) has been implicated in reducing immunotherapy responsiveness by promoting M2-type differentiation of macrophages and facilitating cancer cell metastasis.

METHODS

In this study, we developed macrophage membrane-coated nanoparticles loaded with a TGF-βR1 kinase inhibitor, SD-208 (M[Formula: see text]-SDNP). Inhibitions of M2 macrophage polarization and epithelial-to-mesenchymal transition (EMT) of cancer cells were comprehensively evaluated through in vitro and in vivo experiments. Bio-distribution study and in vivo therapeutic effects of M[Formula: see text]-SDNP were investigated in orthotopic breast cancer model and intraveneously injected metastasis model.

RESULTS

M[Formula: see text]-SDNPs effectively inhibited cancer metastasis and converted the immunosuppressive tumor microenvironment (cold tumor) into an immunostimulatory tumor microenvironment (hot tumor), through specific tumor targeting and blockade of M2-type macrophage differentiation. Administration of M[Formula: see text]-SDNPs considerably augmented the population of cytotoxic T lymphocytes (CTLs) in the tumor tissue, thereby significantly enhancing responsiveness to immune checkpoint inhibitors, which demonstrates a robust anti-cancer effect in conjunction with anti-PD-1 antibodies.

CONCLUSION

Collectively, responsiveness to immune checkpoint inhibitors was considerably enhanced and a robust anti-cancer effect was demonstrated with the combination treatment of M[Formula: see text]-SDNPs and anti-PD-1 antibody. This suggests a promising direction for future therapeutic strategies, utilizing bio-inspired nanotechnology to improve the efficacy of cancer immunotherapy.

Caprin-1 influences autophagy-induced tumor growth and immune modulation in pancreatic cancer

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is characterized by rapid progression and poor prognosis. Understanding the genetic mechanisms that affect cancer properties and reprogram tumor immune microenvironment will develop new strategies to maximize the benefits for cancer therapies.

METHODS

Gene signatures and biological processes associated with advanced cancer and unfavorable outcome were profiled using bulk RNA sequencing and spatial transcriptome sequencing, Caprin-1 was identified as an oncogenesis to expedite pancreatic cancer growth by activating autophagy. The mechanism of Caprin-1 inducing autophagy activation was further explored in vitro and in vivo. In addition, higher level of Caprin-1 was found to manipulate immune responses and inflammatory-related pathways. The immune profiles associated with increased levels of Caprin-1 were identified in human PDAC samples. The roles of CD4+T cells, CD8+T cells and tumor associated macrophages (TAMs) on clinical outcomes prediction were investigated.

RESULTS

Caprin-1 was significantly upregulated in advanced PDAC and correlated with poor prognosis. Caprin-1 interacted with both ULK1 and STK38, and manipulated ULK1 phosphorylation which activated autophagy and exerted pro-tumorigenic phenotypes. Additionally, the infiltrated CD4+T cells and tumor associated macrophages (TAMs) were increased in Caprin-1High tissues. The extensive CD4+T cells determined poor clinical outcome in Caprin-1high patients, arguing that highly expressed Caprin-1 may assist cancer cells to escape from immune surveillance.

CONCLUSIONS

Our findings establish causal links between the upregulated expression of Caprin-1 and autophagy activation, which may manipulate immune responses in PDAC development. Our study provides insights into considering Caprin-1 as potential therapeutic target for PDAC treatment.

Formaldehyde promotes tumor-associated macrophage polarizations and functions through induction of HIF-1α-mediated glycolysis

Formaldehyde (FA) exposure has been positively correlated with many diseases including various types of cancers. However, the mechanisms of FA-related carcinogenesis are still unclear. Tumor-associated macrophages (TAMs) are the most abundant immune cells in tumor microenvironment, which is a heterogeneous population consist of both pro-inflammatory (M1) and immunosuppressive (M2) cells. TAMs are deeply involved in tumor development and progression. Our previous studies demonstrated that FA enhanced M1 polarization of macrophages through induction of HIF-1α-mediated glycolysis. To examine if TAM polarizations are also potentiated by FA, BALB/c nude mice were inoculated with A549 cells to develop subcutaneous tumors and exposed to 2.0 mg/m3 FA for 14 days. Significant increases of both M1 and M2 polarizations of TAMs were observed in tumor tissues of FA-exposed mice. After confirmation of the potentiation effects in RAW264.7 and THP-1-derived in vitro TAM models, FA at 25 and 50 μM was found to enhance TAM immunosuppressive functions and glycolytic metabolism. In addition, FA-induced glycolysis in TAMs was reversed by a specific HIF-1α inhibitor PX-478 at 5 μM, and suppression of glycolytic metabolism with a glucose analog 2-DG at 1 mM also alleviated FA-potentiated TAM functions, which indicated that FA induced TAM polarizations through the upregulation of HIF-1α-mediated glycolysis. These results illustrated a potential carcinogenic mechanism of FA through metabolic disturbance of tumor immunity, which could be utilized to develop preventative or therapeutic agents for FA-induced carcinogenesis and immune disorders.

Lapachol inhibits the growth of lung cancer by reversing M2-like macrophage polarization via activating NF-κB signaling pathway

Resetting tumor-associated macrophages (TAMs) is a promising strategy to ameliorate the immunosuppressive tumor microenvironment (TME) and improve innate and adaptive antitumor immunity. Lapachol, a naturally occurring 1,4-naphthoquinone, exhibits various pharmacological activities including antitumor, anti-leishmanial, antimalarial and antiseptic. In this study, we investigated the relevance of macrophage polarization and the antitumor effect of lapachol in Lewis lung cancer (LLC) both in vitro and in vivo. This study demonstrated that lapachol significantly reversed the polarization of M2-like macrophages thus that were endowed with the ability to kill LLC cells by activating NF-κB signaling pathway. Furthermore, lapachol effectively suppressed tumor growth in C57BL/6 mice bearing lung tumors by reducing the proportion of M2-like macrophages. Overall, our findings clearly illustrated that lapachol could reverse the polarization of M2-like macrophages to improve the immunosuppressive tumor microenvironment, and had the potential to be developed as an immunomodulatory antitumor agent.

Translocator protein (TSPO) expression in neoplastic cells and tumor-associated macrophages in meningiomas

Meningiomas are the most common primary intracranial tumors and show extensive infiltration of macrophages. The mitochondrial membrane protein translocator protein (TSPO) has been used as an in vivo marker of microglia and macrophage activation to visualize neuroinflammation. However, it is unknown which cell types express TSPO in meningiomas. Immunohistochemistry of 38 WHO grade 1-3 meningiomas was subjected to segmentation and deep learning classification of TSPO expression to either Iba1-positive tumor-associated macrophages (TAMs) or all other (mainly neoplastic) cells. A possible association between clinical data and TSPO expression intensities was also investigated. TAMs accounted for 15.9%-26% of all cells in the meningioma tissue. Mean fluorescence intensity of TSPO was significantly higher in TAMs (p < 0.0001), but the mass of neoplastic cells in the tumors exceeded that of TAMs. Thus, the summed fluorescence intensity of TSPO in meningioma cells was 64.1% higher than in TAMs (p = 0.0003). We observed no correlation between TSPO expression intensity and WHO grade. These results indicate that both macrophage-lineage and neoplastic cells in meningiomas express TSPO and that the SPECT-TSPO signal in meningiomas mainly reflects the latter; TSPO is expressed equally in parenchymal activated and resting macrophage/microglia lineage cells.

Blockage of CacyBP inhibits macrophage recruitment and improves anti-PD-1 therapy in hepatocellular carcinoma

BACKGROUND

Despite remarkable advancements in cancer immunotherapy, the overall response rate to anti-programmed cell death-1 (anti-PD-1) therapy in hepatocellular carcinoma (HCC) patients remains low. Our previous study has demonstrated the critical role of CacyBP/SIP (Calcyclin-Binding Protein and Siah-1 Interacting Protein) as a regulator of HCC development and progression. However, the possible impact of CacyBP on the tumor immune microenvironment has not yet been clarified.

METHODS

The expressions of CacyBP and Myd88 in HCC cell lines and tissues was detected by bioinformatics analysis, real-time quantitative PCR, western blotting and immunohistochemistry. The interaction between CacyBP and Myd88 was measured using co-immunoprecipitation and immunofluorescence. In vitro and in vivo assays were used to investigate the regulation of CacyBP on tumor-associated macrophages (TAMs).

RESULTS

We identified that CacyBP was positively correlated with Myd88, a master regulator of innate immunity, and Myd88 was a novel binding substrate downstream of CacyBP in HCC. Additionally, CacyBP protected Myd88 from Siah-1-mediated proteasome-dependent degradation by competitively binding to its Toll/interleukin-1 receptor (TIR) domain. Inhibition of CacyBP-Myd88 signaling subsequently diminished HDAC1-mediated H3K9ac and H3K27ac modifications on the CX3CL1 promoter and reduced its transcription and secretion in HCC cells. Moreover, by using in vitro and in vivo strategies, we demonstrated that depletion of CacyBP impaired the infiltration of TAMs and the immunosuppressive state of the tumor microenvironment, further sensitizing HCC-bearing anti-PD-1 therapy.

CONCLUSIONS

Our findings suggest that targeting CacyBP may be a novel treatment strategy for improving the efficacy of anti-PD-1 immunotherapy in HCC.

TonEBP expression is essential in the IL-1β-induced migration and invasion of human A549 lung cancer cells

Lung cancer has the highest mortality rate among all cancers, in part because it readily metastasizes. The tumor microenvironment, comprising blood vessels, fibroblasts, immune cells, and macrophages [including tumor-associated macrophages (TAMs)], is closely related to cancer cell growth, migration, and invasion. TAMs secrete several cytokines, including interleukin (IL)-1β, which participate in cancer migration and invasion. p21-activated kinase 1 (PAK1), an important signaling molecule, induces cell migration and invasion in several carcinomas. Tonicity-responsive enhancer-binding protein (TonEBP) is also known to participate in cancer cell growth, migration, and invasion. However, the mechanisms by which it increases lung cancer migration remain unclear. Therefore, in this study, we aimed to elucidate the mechanisms by which IL-1β and TonEBP affect lung cancer cell migration and invasion. We found that A549 cocultured-MΦ-secreted IL-1β induced A549 cell migration and invasion via the PAK1 pathway. TonEBP deficiency reduced A549 cell migration and invasion and increased responsiveness to IL-1β-induced migration and invasion. PAK1 phosphorylation, which was promoted by IL-1β, was reduced when TonEBP was depleted. These results suggest that TonEBP plays an important role in IL-1β induction and invasiveness of A549 cells via the PAK1 pathway. These findings could be valuable in identifying potential targets for lung cancer treatment.

Integration of single-cell and bulk RNA sequencing to establish a prognostic signature based on tumor-associated macrophages in colorectal cancer

Several studies have shown significant involvement of tumor-associated macrophages (TAMs) in the tumor microenvironment and cancer progression. However, no data on reliable TAM-related biomarkers are available for predicting the prognosis of patients with colorectal cancer (CRC). We analyzed the clinical data and gene expression profiles of patients with CRC from databases. The single-cell transcriptomic data was applied to identify M2-like TAM-related differentially expressed genes. Univariate Cox and least absolute shrinkage and selection operator regression analyses were used to determine the prognostic signature genes. Then, seven key genes were screened to develop the prognostic signature. In the training and external validation cohorts, the overall survival (OS) of patients in the high-risk group was significantly shorter compared to the low-risk group. Consequently, we created a nomogram that could accurately and reliably predict the prognosis of patient with CRC. A significant correlation was observed between the patient's prognosis, clinical features, sensitivity to anticancer drugs, TME, and risk scores. Moreover, risk score was strongly related to the response to immunotherapy in patients from GSE91061, GSE78220, and GSE60331 cohorts. Finally, high expression of HSPA1A, SERPINA1, CXCL1, and low expression of DNASE1L3 were found in human CRC tissue and normal tissue by using qRT-PCR. In conclusion, the M2-like TAM-related prognostic signature could predict the survival, prognosis, and response of patients with CRC to immunotherapy, which sheds light on the role of TAMs in CRCs and enhances our understanding of TAMs.

Tumor associated macrophages in esophageal squamous carcinoma: Promising therapeutic implications

Esophageal squamous carcinoma (ESCC) is a prevalent and highly lethal malignant tumor, with a five-year survival rate of approximately 20 %. Tumor-associated macrophages (TAMs) are the most prominent immune cells in the tumor microenvironment (TME), comprising over 50 % of the tumor volume. TAMs can be polarized into two distinct phenotypes, M1-type and M2-type, through interactions with cancer cells. M2-type TAMs are more abundant than M1-type TAMs in the TME, contributing to tumor progression, such as tumor cell survival and the construction of an immunosuppressive environment. This review focuses on the role of TAMs in ESCC, including their polarization, impact on tumor proliferation, angiogenesis, invasion, migration, therapy resistance, and immunosuppression. In addition, we discuss the potential of targeting TAMs for clinical therapy in ESCC. A thorough comprehension of the molecular biology about TAMs is essential for the development of innovative therapeutic strategies to treat ESCC.

Icariin inhibits prostate cancer bone metastasis and destruction via suppressing TAM/CCL5-mediated osteoclastogenesis

BACKGROUND

Bone metastasis occurs in nearly 70% of patients with metastatic prostate cancer (PCa), and represents the leading cause of death in patients with PCa. Emerging evidence has demonstrated the potential activities of icariin in modulating bone metabolism and remodelling the tumor microenvironment (TME). However, whether icariin could inhibit PCa bone metastasis and destruction by modulating the TME as well as the underlying mechanisms remains unclear.

PURPOSE

This study investigated whether icariin could inhibit PCa bone metastasis and destruction by modulating the bone TME as well as the underlying mechanisms.

METHODS

Osteoclasts were induced from mouse bone marrow-derived macrophages (BMMs) or Raw264.7 cells. PCa cells were cultured in the conditional medium (CM) of macrophages in vitro or co-injected with macrophages in vivo to simulate their coexistence in the TME. Multiple molecular biology experiments and the mouse RM1-Luc PCa bone metastasis model were used to explore the inhibitory activity and mechanism of icariin on PCa metastasis and bone destruction.

RESULTS

Icariin treatment significantly suppressed PCa growth, bone metastasis and destruction as well as osteoclastogenesis in vivo. Furthermore, icariin remarkably inhibited osteoclast differentiation, even in the presence of the CM of tumor-associated macrophages (TAMs), while exhibiting no obvious effect on osteoblasts. Moreover, icariin suppressed the M2 phenotype polarization of Raw264.7-derived TAMs and transcriptionally attenuated their CC motif chemokine ligand 5 (CCL5) expression and secretion via inhibiting SPI1. Additionally, CCL5 induced the differentiation and chemotaxis of osteoclast precursor cells by binding with its receptor CCR5. The clinicopathological analysis further verified the positive correlation between the TAM/CCL5/CCR5 axis and osteoclastogenesis within the TME of PCa patients. More importantly, icariin remarkably suppressed PCa metastasis-induced bone destruction in vivo by inhibiting osteoclastogenesis via downregulating the TAM/CCL5 pathway.

CONCLUSION

Altogether, these results not only implicate icariin as a promising candidate immunomodulator for PCa bone metastasis and destruction but also shed novel insight into targeting TAM/CCL5-mediated osteoclastogenesis as a potential treatment strategy for osteolytic bone metastasis. This study helps to advance the understanding of the crosstalk between bone TME and bone homeostasis.

A feed-forward loop based on aerobic glycolysis and TGF-β between tumor-associated macrophages and bladder cancer cells promoted malignant progression and immune escape

PURPOSE

Immunotherapy with programmed cell death 1/ligand 1 (PD-1/PD-L1) checkpoint inhibitors has revolutionized the systemic treatment of solid tumors, including bladder cancer. Previous studies have shown that enhanced glycolysis, tumor-associated macrophage (TAM) infiltration, and TGF-β secretion in the tumor microenvironment (TME) are closely related to PD-1/PD-L1 inhibitor immunotherapy resistance. However, the potential mechanism of their interaction in bladder cancer has not been fully uncovered.

METHODS

By coculturing bladder cancer cells and TAMs, we studied the relationship and interaction mechanism between tumor cell glycolysis, TAM functional remodeling, TGF-β positive feedback secretion, and PD-L1 mRNA m6A methylation in the bladder cancer microenvironment.

RESULTS

Bioinformatics analysis and IHC staining found a close correlation between tumor glycolysis, M2 TAM infiltration, and the prognosis of bladder cancer patients. In Vitro experiments demonstrated that bladder cancer cells could re-educate M2 TAMs through lactate and promote TGF-β secretion via the HIF-1α signaling pathway. Reciprocally, in vitro, and in vivo experiments validated that M2 TAMs could promote glycolysis in bladder cancer cells by TGF-β via the Smad2/3 signaling pathways. Furthermore, M2 TAMs could also promote CSCs and EMT of bladder cancer cells. More importantly, we found M2 TAMs enhance PD-L1 mRNA m6A methylation by promoting METLL3 expression in bladder cancer via the TGF-β/Smad2/3 pathway in the TME.

CONCLUSIONS

Our study highlights a feed-forward loop based on aerobic glycolysis and TGF-β between M2 TAMs and bladder cancer cells, which may be a potential mechanism of malignant progression and immunotherapy resistance in bladder cancer.

Development and validation of a disulfidptosis and M2 TAM-related classifier for bladder cancer to explore tumor subtypes, immune landscape and drug treatment

BACKGROUND

Disulfidptosis, as a new mode of programmed cell death, is closely associated with tumorigenesis. Meanwhile, M2 tumor-associated macrophage (TAM) plays an important role in tumor progression. Here, we propose to combine these two perspectives to detect novel disulfidptosis and M2 TAM-related biomarkers in bladder cancer (BCa) to identify various tumor subtypes, construct prognostic features, reveal immune and somatic mutational landscapes, and screen for drugs in BCa.

METHODS

We used weighted gene co-expression network analysis (WGCNA) to mine M2 TAM-related genes. Consensus unsupervised clustering was performed to identify potential tumor subtypes. The least absolute shrinkage and selection operator (LASSO) regression and multivariate Cox regression analyses were utilized to build the risk model. We then explored the immune cell, immune function, immune checkpoint expression patterns and somatic mutational landscape in clusters and risk groups. In addition, we performed sensitivity analysis for anti-cancer drugs.

RESULTS

We identified 3057 M2 TAM-related genes and intersected them with disulfidptosis-related genes to obtain 95 disulfidptosis and M2 TAM-related genes (DMRGs). In terms of tumor subtypes, two molecular clusters were identified. Cluster 1 showed stronger immunogenicity and higher tumor mutational burden (TMB). We also predicted 50 drugs with high sensitivity in cluster 1. On the basis of risk grouping, the high-risk group had poor overall survival in the training, test, and validation groups. Ten screened anti-cancer drugs were more sensitive in the high-risk group. A nomogram predicting survival of BCa patients was also established.

CONCLUSION

By combining two hotspot perspectives, disulfidptosis and M2 TAM, we provide a valuable risk score signature for establishing individualized treatment regimens and drug choices. The risk score may serve as an independent risk factor for BCa patients.

Prognostic impact of soluble PD-L1 derived from tumor-associated macrophages in non-small-cell lung cancer

Programmed cell death-ligand 1 (PD-L1) on tumor cells can be degraded to soluble form (sPD-L1) and enter circulation, however, the clinical significances of sPD-L1 in peripheral blood remains to be elucidated in non-small-cell lung cancer (NSCLC). We monitored plasma sPD-L1 levels during perioperative periods and evaluated PD-L1-positive cells in tumor tissues in patients with operable NSCLC. Then the correlation between preoperative plasma sPD-L1 levels and relapse-free survival (RFS) was analyzed retrospectively. In patients who underwent radical surgery (n = 61), plasma sPD-L1 levels (median; 63.5 pg/mL) significantly increased 1 month after surgery (72.2 pg/mL, P < 0.001). The combined score of PD-L1-positive cells including tumor cells and tumor-associated macrophages (TAMs) was significantly associated with preoperative plasma sPD-L1 levels. In patients with high levels of preoperative plasma sPD-L1, the probability of 5-year RFS was significantly poor for patients with low PD-L1 expression intensity of tumor cells (tcPD-L1) compared with those with high tcPD-L1 (33.3% vs. 87.5%, respectively, P = 0.016; 95% CI, 0.013-0.964). In former group, PD-L1-positive TAMs were markedly infiltrating compared with those from latter group (246.4 vs. 76.6 counts/mm2, respectively, P = 0.003). In NSCLC, plasma sPD-L1 can reflect the accumulation of PD-L1-posotive TAMs, not just PD-L1-positive tumor cells. In patients with high levels of preoperative plasma sPD-L1, the prognoses after surgery depends on which PD-L1-positive cells, tumor cells or TAMs, are the primary source of the sPD-L1. Thus, measuring both plasma sPD-L1 levels and PD-L1 expression status of tumor cells and TAMs is of benefit for assessment of postoperative prognosis in operable NSCLC.

A novel STAT3/ NFκB p50 axis regulates stromal-KDM2A to promote M2 macrophage-mediated chemoresistance in breast cancer

BACKGROUND

Lysine Demethylase 2A (KDM2A) plays a crucial role in cancer cell growth, differentiation, metastasis, and the maintenance of cancer stemness. Our previous study found that cancer-secreted IL-6 can upregulate the expression of KDM2A to promote further the transition of cells into cancer-associated fibroblasts (CAFs). However, the molecular mechanism by which breast cancer-secreted IL-6 regulates the expression of KDM2A remains unclear. Therefore, this study aimed to elucidate the underlying molecular mechanism of IL-6 in regulating KDM2A expression in CAFs and KDM2A-mediated paclitaxel resistance in breast cancer.

METHODS

The ectopic vector expression and biochemical inhibitor were used to analyze the KDM2A expression regulated by HS-578 T conditioned medium or IL-6 in mammary fibroblasts. Immunoprecipitation and chromatin immunoprecipitation assays were conducted to examine the interaction between STAT3 and NFκB p50. M2 macrophage polarization was assessed by analyzing M2 macrophage-specific markers using flow cytometry and RT-PCR. ESTIMATE algorithm was used to analyze the tumor microenvironment-dominant breast cancer samples from the TCGA database. The correlation between stromal KDM2A and CD163 + M2 macrophages was analyzed using the Pearson correlation coefficient. Cell viability was determined using trypan blue exclusion assay.

RESULTS

IL-6 regulates gene expression via activation and dimerization of STAT3 or collaboration of STAT3 and NFκB. However, STAT3, a downstream transcription factor of the IL-6 signaling pathway, was directly complexed with NFκB p50, not NFκB p65, to upregulate the expression of KDM2A in CAFs. Enrichment analysis of immune cells/stromal cells using TCGA-breast cancer RNA-seq data unveiled a positive correlation between stromal KDM2A and the abundance of M2 macrophages. CXCR2-associated chemokines secreted by KDM2A-expressing CAFs stimulated M2 macrophage polarization, which in turn secreted CCL2 to increase paclitaxel resistance in breast cancer cells by activating CCR2 signaling.

CONCLUSION

This study revealed the non-canonical molecular mechanism of IL-6 secreted by breast cancer upregulated KDM2A expression in CAFs via a novel STAT3/NFκB p50 axis, which STAT3 complexed with NFκB p50 in NFκB p50 binding motif of KDM2A promoter. KDM2A-expressing CAFs dominantly secreted the CXCR2-associated chemokines to promote M2 macrophage polarization and enhance paclitaxel resistance in breast cancer. These findings underscore the therapeutic potential of targeting the CXCR2 or CCR2 pathway as a novel strategy for paclitaxel-resistant breast cancer.

Exosome miRNA-203 promotes M1 macrophage polarization and inhibits prostate cancer tumor progression

Prostate cancer (PCa) is a prevalent malignant neoplasm affecting the male reproductive system globally. However, the diagnostic and therapeutic approaches fall short of meeting the demands posed by PCa. Poor expression of miRNA-203 (miR-203) within PCa tissues and cells implies its potential utility as a diagnostic indicator for PCa. Exosomes (Exo), membranous vesicles released by various cells, are rich reservoirs of miRNAs. However, the presence of miR-203 presents within Exo derived from PCa cells remains unclarified. In this study, Exo was isolated from urine specimens collected from clinical PCa patients and LNCaP cells to detect miR-203 expression. Meanwhile, the impact of overexpressed miR-203 on M0 macrophages (mø) was analyzed. Subsequently, alterations in the proliferative, migratory, and invasive capacities of LNCaP cells were examined within a co-culture system featuring elevated miR-203 levels in both macrophages and LNCaP cells. Furthermore, the repercussions of miR-203 upregulation or inhibition were explored in a murine PCa tumor model. The results revealed that Exo manifested a circular or elliptical morphology, encapsulating a phospholipid bilayer approximately 100 nm in diameter. Notably, Exo readily infiltrated, with both Exo and miR-203-overexpressing Exo prompting macrophage polarization toward the M1 subtype. In the co-culture system, miR-203 exhibited pronounced suppression of LNCaP cell proliferation, migration, and invasion, while concurrently fostering apoptosis as compared with the LNCaP group (Control). In vivo experiments further disclosed that miR-203 greatly inhibited the growth of PCa tumors in nude mice. Markedly heightened expression of M1 macrophage markers such as IL-1β, IL-6, IL-12, CXCL9, and CXCL10 was observed within the tumor microenvironment following miR-203 intervention, as opposed to the model group. However, the introduction of miR-203 antagomir led to a reversal in tumor growth trends. This investigation indicates the presence of miR-203 within the urine of PCa patients and Exo originating from cells, and that miR-203 exerted antitumor effect by facilitating M1 macrophage polarization. Our study furnishes valuable insights into the potential applicability of miR-203 as a diagnostic biomarker and therapeutic target for PCa.

DLGAP5 promotes gallbladder cancer migration and tumor-associated macrophage M2 polarization by activating cAMP

BACKGROUND

Although disc large associated protein family (DLGAP5) has been reported to be involved in a variety of tumor pathologic processes, its expression and mechanism in gallbladder cancer (GBC) are still uncertain. Macrophages were divided into M1 and M2 macrophages. TAM is more closely defined as M2 polarized macrophages, which plays a key role in cancer progression.

OBJECTIVE

To clarify the role of disc large associated protein family (DLGAP5) in gallbladder cancer (GBC) progression and investigate the mechanism.

METHODS

Differential genes in 10 normal paracancer tissues and 10 GBC tissues in GSE139682 from NCBI-GEO were analyzed by R language. Bioinformation analysis and clinical sample analysis were performed to detect DLGAP5 expression in GBC and its correlation with prognosis. CCK-8, EDU, transwell, wound closure, and Immunoblot were performed to detect its effects on the function of GBC cells. GST-pulldown showed the direct interact between DLGAP5 and cAMP. Macrophage polarization assay was further conducted to detect the effects of DLGAP5 on macrophage M2 polarization. The tumor growth assays were further conducted to confirm its role in mice.

RESULTS

Biological analysis and clinical samples confirmed that DLGAP5 was increased in GBC and strongly related to poor prognosis in patients with GBC. After overexpression of DLGAP5 in GBC cell lines, such as GBC-SD and NOZ cells, cell proliferation and migration were enhanced, and macrophages were polarized to M2. However, after DLGAP5 is knocked down, there is opposite effect. Mechanistically, DLGAP5 promotes the growth and migration of GBC-SD and NOZ cells and the M2 polarization of THP-1-derived macrophages by activating cyclic adenosine monophosphate (cAMP) pathway. In vivo, GBC-SD with DLGAP5 knockdown was subcutaneously injected into nude mice. It was found that after DLGAP5 knockdown, both tumor volume and tumor were reduced, and indicators related to proliferation and M2 polarization decreased.

CONCLUSION

Our study shows that DLGAP5 is significantly elevated in GBC and is strongly related to poor prognosis in patients with GBC. DLGAP5 promotes GBC proliferation, migration, and M2 polarization of macrophages through cAMP pathway, which provides a theoretical basis for the treatment of GBC and may become a promising therapeutic target.

Tumor-Associated Retinal Pigmentation in Choroidal Melanoma

PURPOSE

To report a previously unrecognized choroidal melanoma clinical feature termed tumor-associated retinal pigmentation (TARP) and determine any correlation with tumor biology.

DESIGN

Imaging and histologic analysis of a retrospective cohort of patients.

PARTICIPANTS

Patients with choroidal melanoma identified as having TARP on funduscopy at the Liverpool Ocular Oncology Centre (LOOC), United Kingdom, from January 2020 through January 2023.

METHODS

Clinical and imaging characteristics of patients diagnosed with choroidal melanoma and exhibiting TARP on fundoscopy were documented. Details of these choroidal melanomas were collated and correlated with histopathology and molecular genetic reports. The chromosome 3 status of each tumor was assessed. In enucleated samples, immunostaining was undertaken to determine the nature of the TARP using specific markers (CD68 and MelanA).

MAIN OUTCOME MEASURES

Features of TARP on widefield fundus color imaging, fundus autofluorescence (FAF), and OCT were described. Tumor chromosome 3 status and the immunoprofile of the TARP also were collated.

RESULTS

Tumor-associated retinal pigmentation had a prevalence rate of 7.47 per 100 cases of choroidal melanoma at the LOOC. Twenty-three eyes with TARP were analyzed, with a mean age of 71.4 years (range, 51-88 years). The median largest basal diameter was 16.10 mm (range, 9.17-21.32 mm), and the mean tumor thickness was 8.04 mm (range, 1.40-13.80 mm). Tumor-associated retinal pigmentation was observed on widefield color fundus imaging, with hypofluorescence on FAF images and represented hyperreflective foci located in intraretinal and subretinal spaces on OCT scans. Seventeen patients (73.9%) underwent enucleation, and 6 patients (26.1%) underwent globe-sparing treatment. Molecular genetic analysis of 20 choroidal melanomas (after enucleation or radiotherapy biopsy) revealed monosomy 3 in 18 tumors (90%). Immunostaining of the TARP in enucleated eyes showed CD68+ melanophages in all 17 patients appearing as scattered cells and aggregates; MelanA findings were negative.

CONCLUSIONS

Tumor-associated retinal pigmentation represents tumor-associated macrophages, not melanocytes, within intraretinal and subretinal spaces of larger choroidal melanomas. Radiation treatments need not involve this area in the treatment plan, minimizing radiation-related complications. This novel clinical sign seems to be linked to tumors of high metastatic-risk clinical and genetic characteristics, with a preponderance having monosomy 3 anomalies.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Subverted macrophages in the triple-negative breast cancer ecosystem

Tumor-associated macrophages (TAMs) are the most critical effector cells of innate immunity and the most abundant tumor-infiltrating immune cells. They play a key role in the clearance of apoptotic bodies, regulation of inflammation, and tissue repair to maintain homeostasis in vivo. With the progression of triple-negative breast cancer（TNBC）, TAMs are "subverted" from tumor-promoting immune cells to tumor-promoting immune suppressor cells, which play a significant role in tumor development and are considered potential targets for cancer therapy. Here, we explored how macrophages, as the most important part of the TNBC ecosystem, are "subverted" to drive cancer evolution and the uniqueness of TAMs in TNBC progression and metastasis. Similarly, we discuss the rationale and available evidence for TAMs as potential targets for TNBC therapy.

ILC1-derived IFN-γ regulates macrophage activation in colon cancer

BACKGROUND

Tumor-associated macrophages (TAMs) are an important subset of innate immune cells in the tumor microenvironment, and they are pivotal regulators of tumor-promoting inflammation and tumor progression. Evidence has proven that TAM numbers are substantially increased in cancers, and most of these TAMs are polarized toward the alternatively activated M2 phenotype; Thus, these TAMs strongly promote the progression of cancer diseases. Type 1 innate lymphocytes (ILC1s) are present in high numbers in intestinal tissues and are characterized by the expression of the transcription factor T-bet and the secretion of interferon (IFN)-γ, which can promote macrophages to polarize toward the classically activated antitumor M1 phenotype. However, the relationship between these two cell subsets in colon cancer remains unclear.

METHODS

Flow cytometry was used to determine the percentages of M1-like macrophages, M2-like macrophages and ILC1s in colon cancer tissues and paracancerous healthy colon tissues in the AOM/DSS-induced mouse model of colon cancer. Furthermore, ILC1s were isolated and bone marrow-derived macrophages were generated to analyze the crosstalk that occurred between these cells when cocultured in vitro. Moreover, ILC1s were adoptively transferred or inhibited in vivo to explore the effects of ILC1s on tumor-infiltrating macrophages and tumor growth.

RESULTS

We found that the percentages of M1-like macrophages and ILC1s were decreased in colon cancer tissues, and these populations were positively correlated. ILC1s promoted the polarization of macrophages toward the classically activated M1-like phenotype in vitro, and this effect could be blocked by an anti-IFN-γ antibody. The in vivo results showed that the administration of the Group 1 innate lymphocyte-blocking anti-NK1.1 antibody decreased the number of M1-like macrophages in the tumor tissues of MC38 tumor-bearing mice and promoted tumor growth, and adoptive transfer of ILC1s inhibited tumors and increased the percentage of M1-like macrophages in MC38 tumor-bearing mice.

CONCLUSIONS

Our studies preliminarily prove for the first time that ILC1s promote the activation of M1-like macrophages by secreting IFN-γ and inhibit the progression of colon cancer, which may provide insight into immunotherapeutic approaches for colon cancer.

Exosomal NOX1 promotes tumor-associated macrophage M2 polarization-mediated cancer progression by stimulating ROS production in cervical cancer: a preliminary study

BACKGROUND

Cervical cancer the fourth most frequently diagnosed cancer and the fourth leading cause of cancer death in women, with an estimated 604,000 new cases and 342,000 deaths worldwide in 2020 for high rates of recurrence and metastasis. Identification of novel targets could aid in the prediction and treatment of cervical cancer. NADPH oxidase 1 (NOX1) gene-mediated production of reactive oxygen species (ROS) could induce migration and invasion of cervical cancer cells. Tumor-associated macrophages (TAMs) play important roles in cervical cancer. Tumor cell-derived exosomes mediate signal transduction between the tumor and tumor microenvironment. Elucidation of the mechanisms of NOX1-carrying exosomes involved in the regulation of TAMs may provide valuable insights into the progression of cervical cancer.

METHODS

Uniformly standardized mRNA data of pan-carcinoma from the UCSC database were downloaded. Expression of NOX1 in tumor and adjacent normal tissues for each tumor type was calculated using R language software and significant differences were analyzed. SNP data set were downloaded for all TCGA samples processed using MuTect2 software from GDC. Cell experiment and animal tumor formation experiment were used to evaluate whether exosomal NOX1 stimulating ROS production to promote M2 polarization of TAM in cervical cancer.

RESULTS

NOX1 is highly expressed with a low mutational frequency in pan-carcinoma. Upregulation of NOX1 may be associated with infiltration of M2-type macrophages in cervical cancer tissues, and NOX1 promotes malignant features of cervical cancer cells by stimulating ROS production. Exosomal NOX1 promotes M2 polarization of by stimulating ROS production. Exosomal NOX1 enhances progression of cervical cancer and M2 polarization in vivo by stimulating ROS production.

CONCLUSION

Exosomal NOX1 promotes TAM M2 polarization-mediated cancer progression through stimulating ROS production in cervical cancer.

Unraveling dynamic interactions between tumor-associated macrophages and consensus molecular subtypes in colorectal cancer: An integrative analysis of single-cell and bulk RNA transcriptome

Background

Accumulating research substantiated that tumor-associated macrophages (TAMs) have a significant impact on the tumorigenesis, progression, and distant metastasis, representing a novel target for various cancers. However, the underlying dynamic changes and interactions between TAMs and tumor cells remain largely elusive in colorectal cancer (CRC).

Methods

We depicted the dynamic changes of macrophages using sing-cell RNA-seq data and extracted TAM differentiation-related genes. Next, we utilized the weighted gene co-expression network analysis (WGCNA) to acquire CMS-related modular genes using bulk RNA-seq data. Finally, we utilized univariate Cox and Lasso Cox regression analyses to identify TAM differentiation-related biomarkers and established a novel risk signature model. We employed quantitative real-time polymerase chain reaction (qRT-PCR) on CRC tissue samples and used immunohistochemistry (IHC) data frome the HPA database to validate the mRNA and protein expression of prognostic genes. The interaction of TAMs and each consensus molecular subtype (CMS) subpopulation was analyzed at the cellular level.

Results

A total of 47,285 cells from single-cell dataset and 1197 CRC patients from bulk dataset were obtained. Among those, 6400 myeloid cells were re-clustered and annotated. RNASE1, F13A1, DAPK1, CLEC10A, RPN2, REG4 and RGS19 were identified as prognostic genes and the risk signature model was established based on the above genes. The qRT-PCR analysis indicated that the expression of RNASE1 and DAPK1 were significantly up-regulated in CRC tumor tissues. The cell-cell communication analysis demonstrated complex interactions between TAMs and CMS malignant cell subpopulations.

Conclusion

This study presents an in-depth dissection of the dynamic features of TAMs in the tumor microenvironment and provides promising therapeutic targets for CRC.

Dose-related immunomodulatory effects of recombinant TRAIL in the tumor immune microenvironment

BACKGROUND

In addition to specifically inducing tumor cell apoptosis, recombinant tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) has also been reported to influence the cancer immune microenvironment; however, its underlying effects and mechanisms remain unclear. Investigating the immunomodulatory effects and mechanisms of recombinant TRAIL in the tumor microenvironment (TME) may provide an important perspective and facilitate the exploration of novel TRAIL strategies for tumor therapy.

METHODS

Immunocompetent mice with different tumors were treated with three doses of recombinant TRAIL, and then the tumors were collected for immunological detection and mechanistic investigation. Methodological approaches include flow cytometry analysis and single-cell sequencing.

RESULTS

In an immunocompetent mouse model, recombinant soluble mouse TRAIL (smTRAIL) had dose-related immunomodulatory effects. The optimal dose of smTRAIL (2 mg/kg) activated innate immune cells and CD8+ T cells, whereas higher doses of smTRAIL (8 mg/kg) promoted the formation of a tumor-promoting immune microenvironment to counteract the apoptotic effects on tumor cells. The higher doses of smTRAIL treatment promoted M2-like macrophage recruitment and polarization and increased the production of protumor inflammatory cytokines, such as IL-10, which deepened the suppression of natural killer (NK) cells and CD8+ T cells in the tumor microenvironment. By constructing an HU-HSC-NPG.GM3 humanized immune system mouse model, we further verified the immunomodulatory effects induced by recombinant soluble human TRAIL (shTRAIL) and found that combinational administration of shTRAIL and trabectedin, a macrophage-targeting drug, could remodel the tumor immune microenvironment, further enhance antitumor immunity, and strikingly improve antitumor effects.

CONCLUSION

Our results highlight the immunomodulatory role of recombinant TRAIL and suggest promising therapeutic strategies for clinical application.

Macrophage-reprogramming upconverting nanoparticles for enhanced TAM-mediated antitumor therapy of hypoxic breast cancer

In an attempt to achieve antitumor effects by switching the phenotype of macrophages from the tumor-promoting M2 type to the tumor-suppressing M1 type, we fabricated mannose-decorated/macrophage membrane-coated, silica-layered NaErF4@NaLuF4 upconverting nanoparticles (UCNPs) co-doped with perfluorocarbon (PFC)/chlorin e6 (Ce6) and loaded with paclitaxel (PTX) (UCNP@mSiO2-PFC/Ce6@RAW-Man/PTX: ∼61 nm; -11.6 mV). These nanoparticles were designed to have two major functionalities, (i) efficient singlet oxygen generation aided by an oxygen supply and (ii) good targeting to tumor-associated macrophage (TAMs) (M2-type), to induce polarization to M1 type macrophages that release proinflammatory cytokines and suppress breast cancers. The primary UCNPs consisted of lanthanide elements (erbium and lutetium) in a core@shell structure, and they facilely emitted 660 nm light in response to a deep-penetrating 808 nm near-infrared laser. Moreover, the UCNPs@mSiO2-PFC/Ce6@RAW-Man/PTX were able to release O2 and generate 1O2 because of the co-doped PFC/Ce6 and upconversion. Our nanocarriers' excellent uptake to RAW 264.7 macrophage cells (M2 type) and efficient M1-type polarization activity were clearly demonstrated using qRT-PCR and immunofluorescence-based confocal laser scanning microscopy. Our nanocarriers displayed significant cytotoxicity to 4T1 cells in 2D culture and 3D co-culture systems of 4T1/RAW 264.7 cells. More importantly, UCNPs@mSiO2-PFC/Ce6@RAW-Man/PTX (+808 nm laser) noticeably suppressed tumor growth in 4T1-xenografted mice, compared with the other treatment groups (332.4 vs. 709.5-1185.5 mm3). We attribute this antitumor efficacy to the prominent M1-type macrophage polarization caused by our nanocarriers through efficient ROS/O2 generation and targeting of M2-type TAMs via mannose ligands on coated macrophage-membrane.

Host obesity alters the ovarian tumor immune microenvironment and impacts response to standard of care chemotherapy

BACKGROUND

The majority of women with epithelial ovarian cancer (OvCa) are diagnosed with metastatic disease, resulting in a poor 5-year survival of 31%. Obesity is a recognized non-infectious pandemic that increases OvCa incidence, enhances metastatic success and reduces survival. We have previously demonstrated a link between obesity and OvCa metastatic success in a diet-induced obesity mouse model wherein a significantly enhanced tumor burden was associated with a decreased M1/M2 tumor-associated macrophage ratio (Liu Y et al. Can, Res. 2015; 75:5046-57).

METHODS

The objective of this study was to use pre-clinical murine models of diet-induced obesity to evaluate the effect of a high fat diet (HFD) on response to standard of care chemotherapy and to assess obesity-associated changes in the tumor microenvironment. Archived tumor tissues from ovarian cancer patients of defined body mass index (BMI) were also evaluated using multiplexed immunofluorescence analysis of immune markers.

RESULTS

We observed a significantly diminished response to standard of care paclitaxel/carboplatin chemotherapy in HFD mice relative to low fat diet (LFD) controls. A corresponding decrease in the M1/M2 macrophage ratio and enhanced tumor fibrosis were observed both in murine DIO studies and in human tumors from women with BMI > 30.

CONCLUSIONS

Our data suggest that the reported negative impact of obesity on OvCa patient survival may be due in part to the effect of the altered M1/M2 tumor-associated macrophage ratio and enhanced fibrosis on chemosensitivity. These data demonstrate a contribution of host obesity to ovarian tumor progression and therapeutic response and support future combination strategies targeting macrophage polarization and/or fibrosis in the obese host.

Tumor-associated macrophages promote cisplatin resistance in ovarian cancer cells by enhancing WTAP-mediated N6-methyladenosine RNA methylation via the CXCL16/CXCR6 axis

PURPOSE

Tumor-promotive tumor-associated macrophages (TAMs) and the CXCL16/CXCR6 axis have been reported to be correlated with the limited efficacy of chemotherapy in ovarian cancer (OC). However, the role of TAM-secreted CXCL16 and the mechanism by which it affects the cisplatin (DDP) resistance of OC cells remain elusive.

METHODS

We induced human THP-1 monocytes to differentiate into macrophages. Next, SKOV3 and TOV-112D cells were co-cultured with the macrophages, followed by incubation with increasing concentrations of DDP. The effects of CXCL16, CXCR6, and WTAP on the DDP resistance of OC cells were investigated using the CCK-8 assay, colony formation assay, flow cytometry, and TUNEL staining. CXCL16 concentrations were determined by ELISA. Quantitative real-time PCR and western blotting were used to examine related markers.

RESULTS

Our results showed that after being co-cultured with TAMs, the DDP resistance of OC cells was significantly enhanced and their CXCL16 levels were elevated. Acquired DDP resistance was characterized by an increased IC50 value for DDP, the formation of cell colonies, and decreased levels of cell apoptosis, which were accompanied by reduced levels of caspase-3 and Bax expression, and increased levels of Bcl-2, PARP1, BRCA1, and BRCA2 expression. Either CXCL16 knockdown in TAMs or CXCR6 knockdown in OC cells suppressed the DDP resistance of OC cells that had been co-cultured with TAMs. Knockdown of CXCL16 affected m6A RNA methylation in OC cells, as reflected by decreased YTHDF1/WTAP expression and increased ALKBH5 expression. WTAP overexpression and knockdown promoted and suppressed the DDP resistance of OC cells, respectively.

CONCLUSION

Tumor-associated macrophages promote the cisplatin resistance of OC cells by enhancing WTAP-mediated N6-methyladenosine RNA methylation via the CXCL16/CXCR6 axis.

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.

[Oral Squamous Cell Carcinoma-Derived Cell-Free DNA Modulates Stemness and Migration of Oral Squamous Cell Carcinoma Cell Line by Inducing M2 Macrophage Polarization]

Objective

To investigate the effect of oral squamous cell carcinoma (OSCC)-derived cell-free DNA (cfDNA) on the polarization of macrophages and the regulatory effect of polarized macrophages on the stemness and migration of OSCC cells.

Methods

A total of 30 OSCC tissue samples, 10 dysplastic oral tissue samples, and 10 normal oral tissue samples were collected. The status of all tissue samples was confirmed by pathology analysis. Immunohistochemical (IHC) staining and immunofluorescence (IF) staining were performed to examine the cell count and location of M2 macrophages in different types of oral tissue samples. The conditioned medium (CM) of OSCC cell line CAL-27 from the human tongue was collected and the cfDNA was concentrated and isolated for identification. The macrophages were treated by cfDNA and their morphological characteristics were observed under microscope. The expression levels of polarization-related indicators were determined by RT-qPCR. CAL-27 cell line was treated with macrophage CM induced by cfDNA and the expression levels of stemness-related genes were determined by RT-qPCR. Scratch-wound assay was conducted to verify that the migration ability of CAL-27 was modulated by macrophages induced by cfDNA.

Results

There were more M2 macrophages in the deep connective tissue of dysplastic oral epithelium and the stroma of OSCC compared with those in the normal oral tissues ( P<0.05). OSCC cell line CAL-27 could secret cfDNA of 10000-15000 bp in length. cfDNA secreted by CAL-27 could induced in macrophages significantly higher expression of M2-macrophage-related genes ( P<0.05). cfDNA-treated macrophages induced significantly increased expression of stemness-related genes in CAL-27 cell line ( P<0.05) and promoted the migration ability of CAL-27 cell line ( P<0.05).

Conclusion

OSCC-derived cfDNA promotes stemness and migration of OSCC cell line by inducing M2 macrophage polarization.

Combination therapy with anti-programmed cell death 1 antibody plus angiokinase inhibitor exerts synergistic antitumor effect against malignant mesothelioma via tumor microenvironment modulation

Malignant pleural mesothelioma (MPM) is an asbestos-related fatal malignant neoplasm. Although there has been no reliable chemotherapeutic regimen other than combination therapy of cisplatin and pemetrexed for two decades, combination of ipilimumab plus nivolumab brought about a better outcome in patients with MPM. Thus, cancer immunotherapy using immune checkpoint inhibitor (ICI) is expected to play a central role in the treatment of MPM. To maximize the antitumor effect of ICI, we evaluated whether nintedanib, an antiangiogenic agent, could augment the antitumor effect of anti-programmed cell death 1 (PD-1) antibody (Ab). Although nintedanib could not inhibit the proliferation of mesothelioma cells in vitro, it significantly suppressed the growth of mesothelioma allografts in mice. Moreover, combination therapy with anti-PD-1 Ab plus nintedanib reduced tumor burden more dramatically compared with nintedanib monotherapy via inducing remarkable necrosis in MPM allografts. Nintedanib did not promote the infiltration of CD8⁺ T cells within the tumor when used alone or in combination with anti-PD-1 Ab but it independently decreased the infiltration of tumor-associated macrophages (TAMs). Moreover, immunohistochemical analysis and ex vivo study using bone marrow-derived macrophages (BMDMs) showed that nintedanib could polarize TAMs from M2 to M1 phenotype. These results indicated that nintedanib had a potential to suppress protumor activity of TAMs both numerically and functionally. On the other hand, ex vivo study revealed that nintedanib upregulated the expression of PD-1 and PD-ligand 1 (PD-L1) in BMDMs and mesothelioma cells, respectively, and exhibited the impairment of phagocytic activity of BMDMs against mesothelioma cells. Co-administration of anti-PD-1 Ab may reactivate phagocytic activity of BMDMs by disrupting nintedanib-induced immunosuppressive signal via binding between PD-1 on BMDMs and PD-L1 on mesothelioma cells. Collectively, combination therapy of anti-PD-1 Ab plus nintedanib enhances the antitumor activity compared with respective monotherapy and can become a novel therapeutic option for patients with MPM.

The Role of Tumor Epithelial-Mesenchymal Transition and Macrophage Crosstalk in Cancer Progression

PURPOSE OF REVIEW

The purpose of this review is to summarize the recently published findings regarding the role of epithelial to mesenchymal transition (EMT) in tumor progression, macrophages in the tumor microenvironment, and crosstalk that exists between tumor cells and macrophages.

RECENT FINDINGS

EMT is a crucial process in tumor progression. In association with EMT changes, macrophage infiltration of tumors occurs frequently. A large body of evidence demonstrates that various mechanisms of crosstalk exist between macrophages and tumor cells that have undergone EMT resulting in a vicious cycle that promotes tumor invasion and metastasis. Tumor-associated macrophages and tumor cells undergoing EMT provide reciprocal crosstalk which leads to tumor progression. These interactions provide potential targets to exploit for therapy.

Insights on hematopoietic cell kinase: An oncogenic player in human cancer

Hematopoietic cell kinase (Hck) is a member of the Src family and is expressed in hematopoietic cells. By regulating multiple signaling pathways, HCK can interact with multiple receptors to regulate signaling events involved in cell adhesion, proliferation, migration, invasion, apoptosis, and angiogenesis. However, aberrant expression of Hck in various hematopoietic cells and solid tumors plays a crucial role in tumor-related properties, including cell proliferation and epithelial-mesenchymal transition. In addition, Hck signaling regulates the function of immune cells such as macrophages, contributing to an immunosuppressive tumor microenvironment. The clinical success of various kinase inhibitors targeting the Src kinase family has validated the efficacy of targeting Src, and therapies with highly selective Hck kinase inhibitors are in clinical trials. This article reviews Hck inhibition as an emerging cancer treatment strategy, focusing on the expressions and functions of Hck in tumors and its impact on the tumor microenvironment. It also explores preclinical and clinical pharmacological strategies for Hck targeting to shed light on Hck-targeted tumor therapy.

Onionin A inhibits small-cell lung cancer proliferation through suppressing STAT3 activation induced by macrophages-derived IL-6 and cell-cell interaction with tumor-associated macrophage

Tumor-associated macrophage (TAM)-derived IL-6 is involved in small-cell lung cancer (SCLC) progression and chemoresistance via the activation of signal transducer and activator of transcription 3 (STAT3) in the tumor microenvironment. This study aimed to identify natural compounds that suppress cell-cell interactions between TAMs and SCLC cells by inhibiting STAT3 activation. We used a library of natural compounds to identify candidate agents possessing anti-SCLC effects by inhibiting macrophage-induced tumor proliferation. SBC-3 and SBC-5, human SCLC cell lines, were used for in vitro experiments. Furthermore, we assessed the efficacy of these candidate agents in a murine xenograft model of human SCLC. Among the natural compounds examined, onionin A (ONA) inhibited IL-6-induced STAT3 activation and SCLC cell proliferation. ONA also reduced the secretion of IL-6 from macrophages and interfered with the direct effect of cell-cell interactions between macrophages and SCLC cells. Furthermore, ONA administration suppressed tumor progression in a tumor-bearing mouse model. ONA was identified as the most useful candidate for targeting cell-cell interactions between cancer cells and TAMs for anti-SCLC therapy.

A positive feedback loop driven by fibronectin and IL-1β sustains the inflammatory microenvironment in breast cancer

Inflammatory alterations of the extracellular matrix shape the tumor microenvironment and promote all stages of carcinogenesis. This study aims to determine the impact of cellular fibronectin on inflammatory facets of tumor-associated macrophages (TAMs) in breast cancer. Cellular fibronectin (FN) harboring the alternatively spliced extra domain A (FN-EDA) was determined to be a matrix component produced by the triple-negative breast cancer (TNBC) cells. High levels of FN-EDA correlated with poor survival in breast cancer patients. The proinflammatory cytokine IL-1β enhanced the expression of cellular fibronectin including FN-EDA. TAMs were frequently observed in the tumor areas rich in FN-EDA. Conditioned media from TNBC cells induced the differentiation of CD206⁺CD163⁺ macrophages and stimulated the STAT3 pathway, ex vivo. In the macrophages, the STAT3 pathway enhanced FN-EDA-induced IL-1β secretion and NF-κB signaling. In conclusion, our data indicate a self-reinforcing mechanism sustained by FN-EDA and IL-1β through NF-κB and STAT3 signaling in TAMs which fosters an inflammatory environment in TNBC.

Repeated activation of Trpv1-positive sensory neurons facilitates tumor growth associated with changes in tumor-infiltrating immune cells

It is considered that sensory neurons extend into the tumor microenvironment (TME), which could be associated with tumor growth. However, little is known about how sensory signaling could promote tumor progression. In this study, chemogenetic activation of transient receptor potential vanilloid 1 (Trpv1)-positive sensory neurons (C-fibers) by the microinjection of AAV-hSyn-FLEX-hM3Dq-mCherry into the sciatic nerve dramatically increased tumor volume in tumor-bearing Trpv1-Cre mice. This activation in Trpv1::hM3Dq mice that had undergone tumor transplantation significantly reduced the population of tumor-infiltrating CD4⁺ T cells and increased the mRNA level of the M2-macrophage marker, CX3C motif chemokine receptor 1 (Cx3cr1) in immunosuppressive cells, such as tumor-associated macrophages (TAMs) and tumor-infiltrating monocytic myeloid-derived suppressor cells (M-MDSCs). Under these conditions, we found a significant correlation between the decreased expression of the M1-macrophage marker Tnf and tumor volume. These findings suggest that repeated activation of Trpv1-positive sensory neurons may facilitate tumor growth along with changes in tumor-infiltrating immune cells.