Tumor-conditioned macrophages secrete migration-stimulating factor: a new marker for M2-polarization, influencing tumor cell motility

Cancer stem cells: Masters of all traits

Cancer is a heterogeneous disease, which contributes to its rapid progression and therapeutic failure. Besides interpatient tumor heterogeneity, tumors within a single patient can present with a heterogeneous mix of genetically and phenotypically distinct subclones. These unique subclones can significantly impact the traits of cancer. With the plasticity that intratumoral heterogeneity provides, cancers can easily adapt to changes in their microenvironment and therapeutic exposure. Indeed, tumor cells dynamically shift between a more differentiated, rapidly proliferating state with limited tumorigenic potential and a cancer stem cell (CSC)-like state that resembles undifferentiated cellular precursors and is associated with high tumorigenicity. In this context, CSCs are functionally located at the apex of the tumor hierarchy, contributing to the initiation, maintenance, and progression of tumors, as they also represent the subpopulation of tumor cells most resistant to conventional anti-cancer therapies. Although the CSC model is well established, it is constantly evolving and being reshaped by advancing knowledge on the roles of CSCs in different cancer types. Here, we review the current evidence of how CSCs play a pivotal role in providing the many traits of aggressive tumors while simultaneously evading immunosurveillance and anti-cancer therapy in several cancer types. We discuss the key traits and characteristics of CSCs to provide updated insights into CSC biology and highlight its implications for therapeutic development and improved treatment of aggressive cancers.

Effect of neoadjuvant chemotherapy on CD14 + CD16 + monocytes and soluble CD163 in Egyptian breast cancer patients

Neoadjuvant chemotherapy (NACT) influences the anticancer response by favourably altering the immune microenvironment. However, the effects of NACT on peripheral monocytes and their prognostic contribution to the NACT response have not yet been clarified. We aimed to evaluate the potential therapeutic responses and possible predictive value of double-positive (CD14 + CD16 +) monocytes and soluble CD163 (sCD163) in Egyptian breast cancer patients. Blood samples were obtained before and after neoadjuvant therapy from 30 patients with invasive breast cancer, and the expression of CD14 and CD16 was assessed via flow cytometry. The patients' sCD163 levels were also determined in both the serum and culture supernatant using enzyme-linked immunosorbent assay (ELISA). The results revealed that NACT was associated with a significant decrease in double-positive monocytes and sCD163 levels. In addition, both double-positive monocytes and serum sCD163 were significantly associated with a partial clinical response. Double-positive monocytes and serum sCD163 levels may be related to therapeutic response, suggesting their possible predictive value in breast cancer patients receiving NACT.

Macrophages are activated toward phagocytic lymphoma cell clearance by pentose phosphate pathway inhibition

Macrophages in the B cell lymphoma microenvironment represent a functional node in progression and therapeutic response. We assessed metabolic regulation of macrophages in the context of therapeutic antibody-mediated phagocytosis. Pentose phosphate pathway (PPP) inhibition induces increased phagocytic lymphoma cell clearance by macrophages in vitro, in primary human chronic lymphocytic leukemia (CLL) patient co-cultures, and in mouse models. Addition of the PPP inhibitor S3 to antibody therapy achieves significantly prolonged overall survival in an aggressive B cell lymphoma mouse model. PPP inhibition induces metabolic activation and pro-inflammatory polarization of macrophages while it decreases macrophages' support for survival of lymphoma cells empowering anti-lymphoma function. As a mechanism of macrophage repolarization, the link between PPP and immune regulation was identified. PPP inhibition causes decreased glycogen level and subsequent modulation of the immune modulatory uridine diphosphate glucose (UDPG)-Stat1-Irg1-itaconate axis. Thus, we hypothesize the PPP as a key regulator and targetable modulator of macrophage activity in lymphoma to improve efficacy of immunotherapies and prolong survival.

BRAFV600E/pTERT double mutated papillary thyroid cancers exhibit immune gene suppression

Introduction

BRAFV600E mutation (BRAFmut) is common in papillary thyroid cancer (PTC), and most patients have an excellent outcome. However, a TERT-promoter mutation (pTERTmut) in the presence of BRAFmut (BRAFmutpTERTmut) has been demonstrated to confer a more aggressive behavior to PTC. Lymphocytic infiltration is often present in PTC. In this study, we sought to decipher the relationship between the BRAF and pTERT mutations and immune gene dysregulation in tumor samples from a cohort of 147 samples of PTC.

Methods

The abundance of 770 immune gene transcripts was determined by multiprex capture/detection and digital counting of mRNA transcripts using the NanoString nCounter® PanCancer Immune Profiling Panel.

Results

We identified 40 immune transcripts differentially expressed in BRAFmutpTERTmut vs BRAFmutpTERT wildtype (pTERTwt) (P<0.05). Transcripts induced by BRAFmut alone were significantly repressed in BRAFmutpTERTmut samples, such as genes expressed by lymphoid cells, antigen-presenting cells, and cytotoxic cells, including chemokines, cytokines, checkpoint control proteins, interferon downstream markers, TNF superfamily proteins and BMP markers. A validation analysis using 444 samples from The Cancer Genome Atlas (TCGA) PTC dataset yielded similar results. Deconvolution analysis confirmed differences in the immune cell populations such as increased presence of M2 macrophages in the BRAFmutpTERTmut Mayo cohort and a lower abundance of M1 macrophages in the BRAFmutpTERTmut TCGA cohort compared to BRAFmutpTERTwt. Most of the immune gene pathways were enriched in the BRAFmutpTERTwt tumors in both Mayo and TCGA cohorts but not in BRAFmutpTERTmut. BRAFmutpTERTwt had higher stromal lymphocytes infiltration as compared to BRAFwtpTERTwt tumors, corroborating the transcriptomic findings.

Discussion

To our knowledge this is the first report of a potential link between TERT and the immune microenvironment, offering an explanation for the aggressive nature of BRAFmutpTERTmut PTC.

NEDD9 is transcriptionally regulated by HDAC4 and promotes breast cancer metastasis and macrophage M2 polarization via the FAK/NF-κB signaling pathway

BACKGROUND

Breast cancer is a malignancy with a generally poor prognosis. With the advancement of molecular research, we have gained deeper insights into the cellular processes that drive breast cancer development. However, the precise mechanisms remain elusive.

RESULTS

Based on the CPTAC database, we found that NEDD9 expression is up-regulated in breast cancer tissues and is associated with poor prognosis in breast cancer patients. Functional experiments showed that NEDD9 promotes tumor growth and metastasis both in vitro and in vivo. Overexpression of NEDD9 disrupts mammary epithelial acinus formation and triggers epithelial-mesenchymal transition in breast cancer cells, effects that are reversed upon NEDD9 gene silencing. Mechanistically, NEDD9 upregulates its expression by inhibiting HDAC4 activity, leading to enhanced H3K9 acetylation of the NEDD9 gene promoter and activation of the FAK/NF-κB signaling pathway. Furthermore, NEDD9 overexpression promotes IL-6 secretion, which further drives breast cancer progression. Notably, NEDD9 activation fosters the pro-tumoral M2 macrophage polarization in the tumor microenvironment. NEDD9 stimulates IL-6 secretion, polarizes monocytes towards an M2-like phenotype, and enhances BC cell invasiveness.

CONCLUSIONS

These findings suggest that NEDD9 upregulation plays a pivotal role in breast cancer metastasis and macrophage M2 polarization via the FAK/NF-κB signaling axis. Targeting NEDD9 may offer a promising therapeutic approach for breast cancer treatment.

Regulatory function of glycolysis-related lncRNAs in tumor progression: Mechanism, facts, and perspectives

Altered metabolism is a hallmark of cancer, and reprogramming of energy metabolism, known as the "Warburg effect", has long been associated with cancer. Cancer cells use the process of glycolysis to quickly manufacture energy from glucose, pyruvic acid, and lactate, which in turn accelerates the growth of cancer and glycolysis becomes a key target for anti-cancer therapies. Recent groundbreaking discoveries regarding long noncoding RNAs (lncRNAs) have opened a new chapter in the mechanism of cancer occurrence. It is widely recognized that lncRNAs regulate energy metabolism through glycolysis in cancer cells. LncRNAs have been demonstrated to engage in several cancer processes such as proliferation, apoptosis, migration, invasion, and chemoresistance, whereas glycolysis is enhanced or inhibited by the dysregulation of lncRNAs. As a result, cancer survival and development are influenced by different signaling pathways. In this review, we summarize the roles of lncRNAs in a variety of cancers and describe the mechanisms underlying their role in glycolysis. Additionally, the predictive potential of glycolysis and lncRNAs in cancer therapy is discussed.

Melatonin downregulates angiogenesis and lymphangiogenesis by regulating tumor-associated macrophages via NLRP3 inflammasomes in lung adenocarcinoma

Tumor-associated macrophages (TAMs), present within the tumor microenvironment (TME), strictly modulate tumor angiogenesis and lymphangiogenesis. Nevertheless, the associated signaling networks and candidate drug targets for these events remains to be elucidated. Given its antioxidative activities, we speculated that melatonin may reduce pyroptosis, and thereby modulate both angiogenesis and lymphangiogenesis. We revealed that a co-culture of A549 cells and THP-1 macrophages strongly enhanced expressions of the NLRP3 inflammasome axis members, and augmented angiogenesis and lymphangiogenesis. Next, we overexpressed NLRP3 in the A549 cells, and demonstrated that excess NLRP3 expression substantially upregulated VEGF and CXCL cytokine expressions, and enhanced lymphatic endothelial cells (LECs) tube formation. In contrast, NLRP3 inhibition produced the opposite effect. In addition, relative to controls, melatonin administration strongly inhibited the NLRP3 inflammasome axis, as well as angiogenesis and lymphangiogenesis in the co-culture system. Subsequent animal experiments using a Lewis Lung Carcinoma (LLC) subcutaneous tumor model in mice corroborate these findings. Melatonin treatment and NLRP3 knockdown significantly inhibit tumor growth and downregulate NLRP3 and IL-1β expression in tumor tissues. Furthermore, melatonin downregulates the expression of angiogenic and lymphangiogenic markers in tumor tissues. Taken together, the evidence suggested that a THP-1 macrophage and A549 cell co-culture stimulates angiogenesis and lymphangiogenesis via the NLRP3 axis. Melatonin protected against the TAMs- and NLRP3 axis-associated promotion of the aforementioned events in vitro and in vivo. Hence, melatonin is a promising candidate for managing for tumor-related angiogenesis and lymphangiogenesis in lung adenocarcinoma.

Dissection of pro-tumoral macrophage subtypes and immunosuppressive cells participating in M2 polarization

Alternatively activated macrophage (M2) polarization can result in one of four subtypes based on cytokines and signaling pathways associated with macrophage activation: M2a, M2b, M2c, and M2d macrophages. The majority of M2 subtypes are anti-inflammatory and pro-angiogenic, secreting growth factors (VEGF, PDGF) and matrix metalloproteinases (MMP2, MMP9) which boost tumor growth, metastasis, and invasion. M2-polarized macrophages are associated with immune suppressor cells harboring Myeloid derived suppressor cells, Regulatory T cells (Tregs), Regulatory B cells as well as alternatively activated (N2) neutrophils. Treg cells selectively support the metabolic stability, mitochondrial integrity, and survival rate of M2-like TAMs in an indirect environment. Also, the contribution of Breg cells influences macrophage polarization towards the M2 direction. TAM is activated when TAN levels in the tumor microenvironment are insufficient or vice versa, suggesting that macrophage and its polarization are fine-tuned. Understanding the functions of immune suppressive cells, mediators, and signaling pathways involved with M2 polarization will allow us to identify potential strategies for targeting the TAM repolarization phenotype for innovative immunotherapy approaches. In this review, we have highlighted the critical factors for M2 macrophage polarization, differential cytokine/chemokine profiles of M1 and M2 macrophage subtypes, and other immune cells' impact on the polarization within the immunosuppressive niche.

MicroRNA-98 as a novel diagnostic marker and therapeutic target in cancer patients

The progress of cancer treatment methods in the last decade has significantly reduced mortality rate among these patients. Nevertheless, cancer is still recognized as one of the main causes of human deaths. One of the main reasons for the high death rate in cancer patients is the late diagnosis in the advanced tumor stages. Therefore, it is necessary to investigate the molecular biology of tumor progressions in order to introduce early diagnostic markers. MicroRNAs (miRNAs) have an important role in regulating cellular processes associated with tumor progression. Due to the high stability of miRNAs in body fluids, they are widely used as non-invasive markers in the early tumor diagnosis. Since, deregulation of miR-98 has been reported in a wide range of cancers, we investigated the molecular mechanisms of miR-98 during tumor progression. It has been reported that miR-98 mainly inhibits the tumor growth by the modulation of transcription factors and signaling pathways. Therefore, miR-98 can be introduced as a tumor marker and therapeutic target among cancer patients.

The selection of animal models influences the assessment of anti-tumor efficacy: promising sialic acid-conjugate modified liposomes demonstrate remarkable therapeutic effects in diverse mouse strains

Mice as a crucial tool for preclinical assessment of antineoplastic agents. The impact of physiological differences among mouse strains on the in vivo efficacy of antitumor drugs, however, has been significantly overlooked. Mononuclear phagocyte system (MPS) is the major player in clearance in vivo, and differences in MPS among different strains may potentially impact the effectiveness of antitumor preparations. Therefore, in this study, we employed conventional liposomes (CL-EPI) and SA-ODA modified liposomes (SAL-EPI) as model preparations to investigate the comprehensive tumor therapeutic effects of CL-EPI and SAL-EPI in KM, BALB/c, and C57BL/6 tumor-bearing mice. The results demonstrated significant variability in the efficacy of CL-EPI for tumor treatment across different mouse strains. Therefore, we should pay attention to the selection of animal models in the study of antitumor agents. SAL-EPI effectively targeted tumor sites by binding to Siglec-1 on the surface of peripheral blood monocytes (PBMs), and achieved good therapeutic effect in different mouse strains with little difference in treatment. The SA modified preparation is therefore expected to achieve a favorable therapeutic effect in tumor patients with different immune states through PBMs delivery (Siglec-1 was expressed in both mice and humans), thereby possessing clinical translational value and promising development prospects.

Thetumor microenvironment'sinpancreatic cancer:Effects onimmunotherapy successandnovel strategiestoovercomethehostile environment

Cancer is a significant global health issue that poses a considerable burden on both patients and healthcare systems. Many different types of cancers exist that often require unique treatment approaches and therapies. A hallmark of tumor progression is the creation of an immunosuppressive environment, which poses complex challenges for current treatments. Amongst the most explored characteristics is a hypoxic environment, high interstitial pressure, and immunosuppressive cells and cytokines. Traditional cancer treatments involve radiotherapy, chemotherapy, and surgical procedures. The advent of immunotherapies was regarded as a promising approach with hopes of greatly increasing patients' survival and outcome. Although some success is seen with various immunotherapies, the vast majority of monotherapies are unsuccessful. This review examines how various aspects of the tumor microenvironment (TME) present challenges that impede the success of immunotherapies. Subsequently, we review strategies to manipulate the TME to facilitate the success of immunotherapies.

Circulating levels of FoxP3, M2 (sCD163) and IGF-1 as potential biomarkers associated with Laryngeal Squamous Cell Carcinoma in Tunisian patients

We aim to assess the clinical impact of circulating levels of sCD163, FoxP3, IGF-1 in LSCC patients (Laryngeal Squamous Cell Carcinoma). The concentrations of sCD163, FoxP3, and IGF-1 were measured using ELISA test in the serum samples collected from 70 pretreatment LSCC patients and 70 age and sex-matched healthy controls. Statistical analysis was performed using ANOVA to compare the two groups, and the correlation between markers and clinical parameters. Receiver-Operator Characteristic (ROC) curve analysis was conducted to determine the optimal cutoff values and evaluate the diagnostic impact of these markers. Significant differences in the levels of sCD163, FoxP3, and IGF-1 were observed between LSCC patients and the control group, with respective p-values of 0.01, 0.022, <0.0001. The determined cutoff values for sCD163, FoxP3, IGF-1 concentrations were 314.55 ng/mL, 1.69 ng/mL, and 1.69 ng/mL, respectively. The corresponding area under the curve (AUC) values were 0.67 (95% CI: 0.57-0.76), 0.70 (95% CI: 0.61-0.80), 0.84 (95% CI: 0.76-0.92), respectively. Furthermore, it was found that IGF-1 concentrations exceeding 125.20 ng/mL were positively correlated with lymph node metastasis. Elevated serum levels of sCD163, FoxP3 and IGF-1 are associated with the diagnosis of LSCC. IGF-1 appears to be the most promising indicator for the LSCC progression.

Melatonin modulates L-arginine metabolism in tumor-associated macrophages by targeting arginase 1 in lymphoma

L-Arginine metabolism plays a crucial role in determining the M1/M2 polarization of macrophages. The M1 macrophages express inducible nitric oxide synthase (iNOS), while the M2 macrophages express arginase 1 and metabolize arginine into nitric oxide and urea, respectively. The tumor microenvironment promotes M2 macrophage polarization and consequently switches the metabolic fate of arginine from nitric oxide towards urea production. Importantly, infiltration of M2 macrophages or tumor-associated macrophages (TAMs) has been correlated with poor prognosis of various cancer types. Melatonin is well reported to have antitumor and immunomodulatory properties. However, whether and how it impacts the polarization of TAMs has not been elucidated. Considering the crucial role of arginine metabolism in macrophage polarization, we were interested to know the fate of L-arginine in TAMs and whether it can be reinstated by melatonin or not. We used a murine model of Dalton's lymphoma and established an in vitro model of TAMs. For TAMs, we used the ascitic fluid of tumor-bearing hosts to activate the macrophages in the presence and absence of lipopolysaccharide (LPS). In these groups, L-arginine metabolism was evaluated, and then the effect of melatonin was assessed in these groups, wherein the metabolic fate of arginine as well as the expression of iNOS and arginase 1 were checked. Furthermore, in the in vivo system of the tumor-bearing host, the effect of melatonin was assessed. The in vitro model of TAMs showed a Th2 cytokine profile, reduced phagocytic activity, and increased wound healing ability. Upon investigating arginine metabolism, we observed high urea levels with increased activity and expression of arginase 1 in TAMs. Furthermore, we observed reduced levels of LPS-induced nitric oxide in TAMs; however, their iNOS expression was comparable. With melatonin treatment, urea level decreased significantly, while the reduction in nitric oxide level was not as significant as observed in its absence in TAMs. Also, melatonin significantly reduced arginase activity and expression at the transcriptional and translational levels, while iNOS expression was affected only at the translational level. This effect was further investigated in the in vivo system, wherein melatonin treatment reversed the metabolic fate of arginine, from urea towards nitric oxide, within the tumor microenvironment. This effect was further correlated with pro-apoptotic tumor cell death in the in vivo system. Our results reinforced the immunomodulatory role of melatonin and offered a strong prospect for activating the anti-tumor immune response in cancer conditions.

Tn antigen interactions of macrophage galactose-type lectin (MGL) in immune function and disease

Protein-carbohydrate interactions are essential in maintaining immune homeostasis and orchestrating inflammatory and regulatory immune processes. This review elucidates the immune interactions of macrophage galactose-type lectin (MGL, CD301) and Tn carbohydrate antigen. MGL is a C-type lectin receptor (CLR) primarily expressed by myeloid cells such as macrophages and immature dendritic cells. MGL recognizes terminal O-linked N-acetylgalactosamine (GalNAc) residue on the surface proteins, also known as Tn antigen (Tn). Tn is a truncated form of the elongated cell surface O-glycan. The hypoglycosylation leading to Tn may occur when the enzyme responsible for O-glycan elongation-T-synthase-or its associated chaperone-Cosmc-becomes functionally inhibited. As reviewed here, Tn expression is observed in many different neoplastic and non-neoplastic diseases, and the recognition of Tn by MGL plays an important role in regulating effector T cells, immune suppression, and the recognition of pathogens.

TTC7B is a new prognostic biomarker in head and neck squamous cell carcinoma linked to immune infiltration and ferroptosis

OBJECTIVE

To investigate the expression of TTC7B and its prognostic significance, biological roles, and impact on the immune system in patients with head and neck squamous cell carcinoma (HNSCC).

MATERIALS AND METHODS

Clinical and genomic data were obtained from TCGA (The Cancer Genome Atlas), GEO (Gene Expression Omnibus), GEPIA2 (Gene Expression Profiling Interactive Analysis 2.0), and TIMER2.0 (Tumor Immune Estimation Resource 2.0) databases. R software was utilized to process the retrieved data. qPCR and immunohistochemical assays were performed to validate the findings obtained from the databases.

RESULTS

High expression of TTC7B was observed in HNSCC, and this heightened expression is significantly associated with reduced overall survival (OS) in patients, making it an independent risk factor impacting OS. TTC7B is correlated with focal adhesions and cell migration pathways based on functional enrichment analysis. CIBERSORT analysis and TIMER2.0 show a positive link between TTC7B and multiple immune cells, particularly macrophages. Pearson's analysis reveals a significant correlation between TTC7B and ferroptosis-related genes.

CONCLUSION

In all, TTC7B could serve as a promising prognostic indicator of HNSCC, and is closely associated with focal adhesions, immune infiltration, and ferroptosis.

Cellular crosstalk of macrophages and therapeutic implications in non-small cell lung cancer revealed by integrative inference of single-cell transcriptomics

Introduction: Non-small cell lung cancer (NSCLC) exhibits heterogeneity with diverse immune cell infiltration patterns that can influence tumor cell behavior and immunotherapy. A comprehensive characterization of the tumor microenvironment can guide precision medicine. Methods: Here, we generated a single-cell atlas of 398170 cells from 52 NSCLC patients, and investigated the imprinted genes and cellular crosstalk for macrophages. Subsequently, we evaluated the effect of tumor cells on macrophages and verified the expression of marker genes using co-culture experiments, flow cytometry and RT-qPCR assays. Results: Remarkable macrophage adaptability to NSCLC environment was observed, which contributed to generating tumor-associated macrophages (TAMs). We identified 5 distinct functional TAM subtypes, of which the majority were SELENOP-positive macrophages, with high levels of SLC40A1 and CCL13. The TAMs were also involved in mediating CD8+ T cell activity and form intercellular interaction with cancer cells, as indicated by receptor-ligand binding. Indirect coculture of tumor cells SPC-A1 and THP-1 monocytes, produced M2-like TAMs that highly expressed several markers of SELENOP-positive macrophages. The abundance of this type TAMs seemed to be associated with poorer overall survival rates [hazard ratio (HR) = 1.34, 95% confidence interval (CI) = 0.98-1.83, p = 0.068] based on deconvolution of TCGA-LUAD dataset. Discussion: In summary, we provided a high-resolution molecular resource of TAMs, and displayed the acquired properties in the tumor microenvironment. Dynamic crosstalk between TAMs and tumor cells via multiple ligand-receptor pairs were revealed, emphasizing its role in sustaining the pro-tumoral microenvironment and its implications for cancer therapy.

Lactic acid-induced M2-like macrophages facilitate tumor cell migration and invasion via the GPNMB/CD44 axis in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is the most prevalent form of oral and maxillofacial malignancies, characterized by a low five-year survival rate primarily caused by invasion and metastasis. The progression of OSCC is influenced by macrophage-mediated immunosuppression, which contributes to both local invasion and distant metastasis. Herein, it is of great necessity to explore the molecular mechanisms underlying the crosstalk between OSCC cells and macrophages, as it remains unclear. In the present study, we found that lactic acid orchestrated intracellular communication in the tumor microenvironment. Glycoprotein non-metastatic protein B (GPNMB), a remarkable molecule preferentially expressed by tumor-associated macrophages (TAMs), was significantly highly expressed in the OSCC tissue. The results showed that lactic acid induced macrophage polarization towards an M2-like phenotype and orchestrated GPNMB secretion from macrophages. Furthermore, paracrine GPNMB played a critical role in triggering tumor-promoting activities such as facilitating tumor cell migration, invasion, and epithelial-mesenchymal transition (EMT). In terms of molecular mechanism, GPNMB functionally interacted with the CD44 receptor, and then partially activated the PI3K/AKT/mTOR signaling cascade. Silencing of CD44 could attenuate the tumor-promoting effects of GPNMB in OSCC cells. Collectively, our findings decipher a positive feedback loop in which tumor cells metabolically interact with macrophages in the OSCC microenvironment, highlighting the potential for therapeutic targeting of the GPNMB/CD44 axis as a promising strategy for treating OSCC.

Crotoxin Modulates Macrophage Phenotypic Reprogramming

Macrophage plasticity is a fundamental feature of the immune response since it favors the rapid and adequate change of the functional phenotype in response to the pathogen or the microenvironment. Several studies have shown that Crotoxin (CTX), the major toxin of the Crotalus durissus terrificus snake venom, has a long-lasting antitumor effect both in experimental models and in clinical trials. In this study, we show the CTX effect on the phenotypic reprogramming of macrophages in the mesenchymal tumor microenvironment or those obtained from the peritoneal cavity of healthy animals. CTX (0.9 or 5 μg/animal subcutaneously) administered concomitantly with intraperitoneal inoculation of tumor cells (1 × 107/0.5 mL, injected intraperitoneally) of Ehrlich Ascitic Tumor (EAT) modulated the macrophages phenotype (M1), accompanied by increased NO• production by cells from ascites, and was evaluated after 13 days. On the other hand, in healthy animals, the phenotypic profile of macrophages was modulated in a dose-dependent way at 0.9 μg/animal: M1 and at 5.0 μg/animal: M2; this was accompanied by increased NO• production by peritoneal macrophages only for the dose of 0.9 μg/animal of CTX. This study shows that a single administration of CTX interferes with the phenotypic reprogramming of macrophages, as well as with the secretory state of cells from ascites, influencing events involved with mesenchymal tumor progression. These findings may favor the selection of new therapeutic targets to correct compromised immunity in different systems.

OTUB1's role in promoting OSCC development by stabilizing RACK1 involves cell proliferation, migration, invasion, and tumor-associated macrophage M1 polarization

Ovarian tumor domain, ubiquitin aldehyde binding 1 (OTUB1), a deubiquitinating enzyme known to regulate the stability of downstream proteins, has been reported to regulate various cancers tumorigenesis, yet its direct effects on oral squamous cell carcinoma (OSCC) progression are unclear. Bioinformatics analysis was performed to screen for genes of interest, and in vitro and in vivo studies were carried out to investigate the function and mechanism of OTUB1 in OSCC. We found that OTUB1 was abnormally elevated in OSCC tissues and positively associated with the pathological stage and tumor stage. Knockdown of OTUB1 impaired the malignance of OSCC cells - suppressed cell proliferation, invasion, migration, and xenografted tumor growth. OTUB1 silencing also drove tumor-associated macrophage M1 polarization but suppressed M2 polarization, and the induction of M1 polarization inhibited the survival of OSCC cells. However, OTUB1 overexpression exerted the opposite effects. Furthermore, the protein network that interacted with the OTUB1 protein was constructed based on the GeneMANIA website. Receptor for activated C kinase 1 (RACK1), a facilitator of OSCC progression, was identified as a potential target of the OTUB1 protein. We revealed that OTUB1 positively regulated RACK1 expression and inhibited RACK1 ubiquitination. Additionally, RACK1 upregulation reversed the effects of OTUB1 knockdown on OSCC progression. Overall, we demonstrated that OTUB1 might regulate OSCC progression by maintaining the stability of the RACK1 protein. These findings highlight the potential roles of the OTUB1/RACK1 axis as a potential therapeutic target in OSCC.

Peanut sprout tea extract inhibits lung metastasis of 4T1 murine mammary carcinoma cells by suppressing the crosstalk between cancer cells and macrophages in BALB/c mice

BACKGROUND/OBJECTIVES

As peanuts germinate, the content of the components beneficial to health, such as resveratrol, increases within the peanut sprout. This study examined whether the ethanol extract of peanut sprout tea (PSTE) inhibits breast cancer growth and metastasis.

MATERIALS/METHODS

After orthotopically injecting 4T1 cells into BALB/c mice to induce breast cancer, 0, 30, or 60 mg/kg body weight/day of PSTE was administered orally. Angiogenesis-related protein expression in the tumors and the degree of metastasis were analyzed. 4T1 and RAW 264.7 cells were co-cultured, and reverse transcription polymerase chain reaction was performed to measure the crosstalk between breast cancer cells and macrophages.

RESULTS

PSTE reduced tumor growth and lung metastasis. In particular, PSTE decreased matrix metalloproteinase-9, platelet endothelial cell adhesion molecule-1, vascular endothelial growth factor-A, F4/80, CD11c, macrophage mannose receptor, macrophage colony-stimulating factor, and monocyte chemoattractant protein 1 expression in the tumors. Moreover, PSTE prevented 4T1 cell migration, invasion, and macrophage activity in RAW 264.7 cells. PSTE inhibited the crosstalk between 4T1 cells and RAW 264.7 cells and promoted the macrophage M1 subtype while inhibiting the M2 subtype.

CONCLUSIONS

These results suggest that PSTE blocks breast cancer growth and metastasis to the lungs. This may be because the PSTE treatment inhibits the crosstalk between mammary cancer cells and macrophages and inhibits the differentiation of macrophages into the M2 subtype.

MiR-146a-5p enrichment in small-extracellular vesicles of relapsed pediatric ALCL patients promotes macrophages infiltration and differentiation

Anaplastic large cell lymphoma (ALCL) is a CD30-positive lymphoma accounting for 20% of all pediatric T-cell lymphomas. Current first line treatment can cure most of ALCL patients but 10-30% of them are resistant or relapse. In this context, liquid biopsy has the potential to help clinicians in disease screening and treatment response monitoring. Small-RNA-sequencing analysis performed on plasma small-extracellular vesicles (s-EVs) from 20 pediatric anaplastic lymphoma kinase positive (ALK + ) ALCL patients at diagnosis revealed a specific miRNAs cargo in relapsed patients compared to non-relapsed, with seven miRNAs enriched in s-EVs of relapsed patients. MiR-146a-5p and miR-378a-3p showed a negative prognostic impact both in univariate and multivariate analysis, possibly representing, together with let-7 g-5p, a miRNA panel for the early identification of high-risk patients. Among them, miR-146a-5p is known to modulate tumor supporting-M2 macrophages differentiation, but the role of these cells in pediatric ALK + ALCL is still unknown. To elucidate the role of miR-146a-5p and M2 macrophages in pediatric ALCL disease, THP-1-derived macrophages were treated with s-EVs from ALK + ALCL cell lines, showing increased miR-146a-5p intracellular expression, migrating capability and M2-markers CD163 and Arginase-1 upregulation. In turn, conditioned media from M2 macrophages or miR-146a-5p-transfected THP-1 increased ALCL cells' aggressive features and were enriched in interleukin-8. Overall, these data suggest a role of miR-146a-5p in promoting macrophage infiltration and M2-like polarization in ALCL. Our findings incite further investigation on the role of M2 macrophages in ALCL aggressiveness and dissemination, also considering the novel treatment options targeting tumor associated macrophages.

Harnessing Nanomaterials for Cancer Sonodynamic Immunotherapy

Immunotherapy has made remarkable strides in cancer therapy over the past decade. However, such emerging therapy still suffers from the low response rates and immune-related adverse events. Various strategies have been developed to overcome these serious challenges. Therein, sonodynamic therapy (SDT), as a non-invasive treatment, has received ever-increasing attention especially in the treatment of deep-seated tumors. Significantly, SDT can effectively induce immunogenic cell death to trigger systemic anti-tumor immune response, termed sonodynamic immunotherapy. The rapid development of nanotechnology has revolutionized SDT effects with robust immune response induction. As a result, more and more innovative nanosonosensitizers and synergistic treatment modalities are established with superior efficacy and safe profile. In this review, the recent advances in cancer sonodynamic immunotherapy are summarized with a particular emphasis on how nanotechnology can be explored to harness SDT for amplifying anti-tumor immune response. Moreover, the current challenges in this field and the prospects for its clinical translation are also presented. It is anticipated that this review can provide rational guidance and facilitate the development of nanomaterials-assisted sonodynamic immunotherapy, helping to pave the way for next-generation cancer therapy and eventually achieve a durable response in patients.

Mannose-modified hyaluronic acid nanocapsules for the targeting of tumor-associated macrophages

Tumor-associated macrophages (TAMs), a class of immune cells that play a key role in tumor immunosuppression, are recognized as important targets to improve cancer prognosis and treatment. Consequently, the engineering of drug delivery nanocarriers that can reach TAMs has acquired special relevance. This work describes the development and biological evaluation of a panel of hyaluronic acid (HA) nanocapsules (NCs), with different compositions and prepared by different techniques, designed to target macrophages. The results showed that plain HA NCs did not significantly influence the polarization of M0 and M2-like macrophages towards an M1-like pro-inflammatory phenotype; however, the chemical functionalization of HA with mannose (HA-Man) led to a significant increase of NCs uptake by M2 macrophages in vitro and to an improved biodistribution in a MN/MNCA1 fibrosarcoma mouse model with high infiltration of TAMs. These functionalized HA-Man NCs showed a higher accumulation in the tumor compared to non-modified HA NCs. Finally, the pre-administration of the liposomal liver occupying agent Nanoprimer™ further increased the accumulation of the HA-Man NCs in the tumor. This work highlights the promise shown by the HA-Man NCs to target TAMs and thus provides new options for the development of nanomedicine and immunotherapy-based cancer treatments.

Tumor-Associated Macrophages in Multiple Myeloma: Key Role in Disease Biology and Potential Therapeutic Implications

Multiple myeloma (MM) is characterized by multiple relapse and, despite the introduction of novel therapies, the disease becomes ultimately drug-resistant. The tumor microenvironment (TME) within the bone marrow niche includes dendritic cells, T-cytotoxic, T-helper, reactive B-lymphoid cells and macrophages, with a complex cross-talk between these cells and the MM tumor cells. Tumor-associated macrophages (TAM) have an important role in the MM pathogenesis, since they could promote plasma cells proliferation and angiogenesis, further supporting MM immune evasion and progression. TAM are polarized towards M1 (classically activated, antitumor activity) and M2 (alternatively activated, pro-tumor activity) subtypes. Many studies demonstrated a correlation between TAM, disease progression, drug-resistance and reduced survival in lymphoproliferative neoplasms, including MM. MM plasma cells in vitro could favor an M2 TAM polarization. Moreover, a possible correlation between the pro-tumor effect of M2 TAM and a reduced sensitivity to proteasome inhibitors and immunomodulatory drugs was hypothesized. Several clinical studies confirmed CD68/CD163 double-positive M2 TAM were associated with increased microvessel density, chemoresistance and reduced survival, independently of the MM stage. This review provided an overview of the biology and clinical relevance of TAM in MM, as well as a comprehensive evaluation of a potential TAM-targeted immunotherapy.

A clinicopathological analysis of supratentorial ependymoma, ZFTA fusion-positive: utility of immunohistochemical detection of CDKN2A alterations and characteristics of the immune microenvironment

EPN-ZFTA is a rare brain tumor where prognostic factors remain unclear and no effective immunotherapy or chemotherapy is currently available. Therefore, this study investigated its clinicopathological features, evaluated the utility of MTAP and p16 IHC as surrogate markers of CDKN2A alterations, and characterized the immune microenvironment of EPN-ZFTA. Thirty surgically removed brain tumors, including 10 EPN-ZFTA, were subjected to IHC. MLPA was performed for CDKN2A HD in 20 ependymal tumors, including EPN-ZFTA. The 5-years OS and PFS of EPN-ZFTA were 90% and 60%, respectively. CDKN2A HD was detected in two cases of EPN-ZFTA; these cases were immunohistochemically negative for both MTAP and p16 and recurred earlier after surgery. As for the immune microenvironment of EPN-ZFTA, B7-H3, but not PD-L1, was positive in all cases of EPN-ZFTA; Iba-1-positive or CD204-positive macrophages were large, while infiltrating lymphocytes were small, in number in EPN-ZFTA. Collectively, these results indicate the potential of MTAP and p16 IHC as useful surrogate markers of CDKN2A HD in EPN-ZFTA, and tumor-associated macrophages, including the M2 type, may contribute to its immune microenvironment. Furthermore, the expression of B7-H3 in EPN-ZFTA may indicate the usefulness of B7-H3 as a target of immune checkpoint chemotherapy for EPN-ZFTA via B7-H3 pathway.

Important functional role of the protein osteopontin in the progression of malignant pleural mesothelioma

Background

Malignant Pleural Mesothelioma (MPM) is an aggressive cancer of the mesothelial lining associated with exposure to airborne non-degradable asbestos fibers. Its poor response to currently available treatments prompted us to explore the biological mechanisms involved in its progression. MPM is characterized by chronic non-resolving inflammation; in this study we investigated which inflammatory mediators are mostly expressed in biological tumor samples from MPM patients, with a focus on inflammatory cytokines, chemokines and matrix components.

Methods

Expression and quantification of Osteopontin (OPN) was detected in tumor and plasma samples of MPM patients by mRNA, immunohistochemistry and ELISA. The functional role of OPN was investigated in mouse MPM cell lines in vivo using an orthotopic syngeneic mouse model.

Results

In patients with MPM, the protein OPN was significantly more expressed in tumors than in normal pleural tissues and predominantly produced by mesothelioma cells; plasma levels were elevated in patients and associated with poor prognosis. However, modulation of OPN levels was not significantly different in a series of 18 MPM patients receiving immunotherapy with durvalumab alone or with pembrolizumab in combination with chemotherapy, some of whom achieved a partial clinical response. Two established murine mesothelioma cell lines: AB1 and AB22 of sarcomatoid and epithelioid histology, respectively, spontaneously produced high levels of OPN. Silencing of the OPN gene (Spp1) dramatically inhibited tumor growth in vivo in an orthotopic model, indicating that OPN has an important promoting role in the proliferation of MPM cells. Treatment of mice with anti-CD44 mAb, blocking a major OPN receptor, significantly reduced tumor growth in vivo.

Conclusion

These results demonstrate that OPN is an endogenous growth factor for mesothelial cells and inhibition of its signaling may be helpful to restrain tumor progression in vivo. These findings have translational potential to improve the therapeutic response of human MPM.

Sunitinib suppresses M2 polarization of macrophages in tumor microenvironment to regulate hepatocellular carcinoma progression

This work aimed to investigate the role and mechanism of Sunitinib (Sun) in suppressing M2 polarization of macrophages in tumor microenvironment (TME). IL-4 was applied to induce the M2 polarization of RAW264.7 cells, followed by treatment with Sun at 50 and 100 nM. Flow cytometry (FCM) was conducted to detect the proportion of F4/80 + CD206 + cells. Enzyme-linked immunosorbent assay (ELISA) was performed to measure the levels of IL-10, Arg-1 and VEGF. Immunofluorescence (IF) staining was carried out to detect the expression of CD206 and Arg-1. Besides, western-Blot (WB) assay was performed to measure the levels of p-JAK1 and p-STAT6 proteins. After polarization, the macrophage culture medium was employed to culture hepatocellular carcinoma (HCC) Hca-F cells. Thereafter, Transwell assays were conducted to examine cell invasion and migration, whereas plate clone formation assay was carried out to detect the clone forming capacity. In further experiments, cells were treated with the STAT6 inhibitor, or STAT6 inhibitor + Sun. Then, the polarization levels of RAW264.7 cells were detected. Moreover, this study established the xenograft tumor mouse model. Later, CD206 and Ki67 expression, IL-10, Arg-1 and VEGF expression levels in tissues, and p-JAK1 and p-STAT6 protein levels were detected by histochemical staining. Sun suppressed the M2 polarization of RAW264.7 cells. Compared with IL-4 treatment, the proportion of F4/80 + CD206 + cells decreased. Meanwhile, the levels of IL-10, Arg-1 and VEGF were downregulated, and the phosphorylation level of JAK1-STAT6 signaling was suppressed. After being cocultured with Hca-F, the malignant behaviors of HCC cells were suppressed after Sun treatment. Similarly, STAT6 inhibitor treatment suppressed the M2 polarization, while the combined application of Sun did not further restrain the polarization level. In the mouse model, Sun suppressed the expression of CD206 and Ki67, simultaneously inhibiting the polarization of JAK1-STAT6 signaling. Sunitinib can suppress the M2 polarization of macrophages to exert the anti-HCC effect, which is its another anticancer mechanism.

Matrix stiffness enhances cancer-macrophage interactions and M2-like macrophage accumulation in the breast tumor microenvironment

The role of intratumor heterogeneity is becoming increasingly apparent in part due to expansion in single cell technologies. Clinically, tumor heterogeneity poses several obstacles to effective cancer therapy dealing with biomarker variability and treatment responses. Matrix stiffening is known to occur during tumor progression and contribute to pathogenesis in several cancer hallmarks, including tumor angiogenesis and metastasis. However, the effects of matrix stiffening on intratumor heterogeneity have not been thoroughly studied. In this study, we applied single-cell RNA sequencing to investigate the differences in the transcriptional landscapes between stiff and compliant MMTV-PyMT mouse mammary tumors. We found similar compositions of cancer and stromal subpopulations in compliant and stiff tumors but differential intercellular communication and a significantly higher concentration of tumor-promoting, M2-like macrophages in the stiffer tumor microenvironments. Interestingly, we found that cancer cells seeded on stiffer substrates recruited more macrophages. Furthermore, elevated matrix stiffness increased Colony Stimulating Factor 1 (CSF-1) expression in breast cancer cells and reduction of CSF-1 expression on stiffer substrates reduced macrophage recruitment. Thus, our results demonstrate that tissue phenotypes were conserved between stiff and compliant tumors but matrix stiffening altered cell-cell interactions which may be responsible for shifting the phenotypic balance of macrophages residing in the tumor microenvironment towards a pro-tumor progression M2 phenotype. STATEMENT OF SIGNIFICANCE: Cells within tumors are highly heterogeneous, posing challenges with treatment and recurrence. While increased tissue stiffness can promote several hallmarks of cancer, its effects on tumor heterogeneity are unclear. We used single-cell RNA sequencing to investigate the differences in the transcriptional landscapes between stiff and compliant MMTV-PyMT mouse mammary tumors. We found similar compositions of cancer and stromal subpopulations in compliant and stiff tumors but differential intercellular communication and a significantly higher concentration of tumor-promoting, M2-like macrophages in the stiffer tumor microenvironments. Using a biomaterial-based platform, we found that cancer cells seeded on stiffer substrates recruited more macrophages, supporting our in vivo findings. Together, our results demonstrate a key role of matrix stiffness in affecting cell-cell communication and macrophage recruitment.

Increased OIT3 in macrophage promotes PD-L1 expression and hepatocellular carcinogenesis via NF-κB signaling

Oncoprotein-induced transcript 3 (OIT3) facilitates macrophage M2 polarization and hepatocellular carcinoma (HCC) progression, however, whether OIT3 regulates tumor immunity remains largely unknown. Here we found that OIT3 was upregulated in HCC-associated macrophages, which inhibited CD4⁺ and CD8⁺ T-cell infiltration in the tumor microenvironment (TME). Mechanistically, OIT3 increased the expression of PD-L1 on tumor-associated macrophages (TAMs) by activating NF-κB signaling, blockade of NF-κB reversed the immunosuppressive activity of TAMs and dampens HCC tumorigenesis. Our findings provide the molecular basis for OIT3 enhancing tumor immunosuppression and highlighted a potential therapeutic strategy for targeting the TAMs of HCC.

Diabetes is accompanied by secretion of pro-atherosclerotic exosomes from vascular smooth muscle cells

BACKGROUND

Atherosclerosis is a common co-morbidity of type 2 diabetes mellitus. Monocyte recruitment by an activated endothelium and the pro-inflammatory activity of the resulting macrophages are critical components of atherosclerosis. Exosomal transfer of microRNAs has emerged as a paracrine signaling mechanism regulating atherosclerotic plaque development. MicroRNAs-221 and -222 (miR-221/222) are elevated in vascular smooth muscle cells (VSMCs) of diabetic patients. We hypothesized that the transfer of miR-221/222 via VSMC-derived exosomes from diabetic sources (DVEs) promotes increased vascular inflammation and atherosclerotic plaque development.

METHODS

Exosomes were obtained from VSMCs, following exposure to non-targeting or miR-221/-222 siRNA (-KD), isolated from diabetic (DVEs) and non-diabetic (NVEs) sources and their miR-221/-222 content was measured using droplet digital PCR (ddPCR). Expression of adhesion molecules and the adhesion of monocytes was measured following exposure to DVEs and NVEs. Macrophage phenotype following exposure to DVEs was determined by measuring mRNA markers and secreted cytokines. Age-matched apolipoprotein-E-deficient mice null (ApoE^-/-) mice were maintained on Western diet for 6 weeks and received injections of saline, NVEs, NVE-KDs, DVEs or DVE-KDs every other day. Atherosclerotic plaque formation was measured using Oil Red Oil staining.

RESULTS

Exposure of human umbilical vein and coronary artery endothelial cells to DVEs, but not NVEs, NVE-KDs, or DVE-KDs promoted increased intercellular adhesion molecule-1 expression and monocyte adhesion. DVEs but not NVEs, NVE-KDs, or DVE-KDs also promoted pro-inflammatory polarization of human monocytes in a miR-221/222 dependent manner. Finally, intravenous administration of DVEs, but not NVEs, resulted in a significant increase in atherosclerotic plaque development.

CONCLUSION

These data identify a novel paracrine signaling pathway that promotes the cardiovascular complications of diabetes mellitus.

TREM2 inhibition triggers antitumor cell activity of myeloid cells in glioblastoma

Triggering receptor expressed on myeloid cells 2 (TREM2) plays important roles in brain microglial function in neurodegenerative diseases, but the role of TREM2 in the GBM TME has not been examined. Here, we found that TREM2 is highly expressed in myeloid subsets, including macrophages and microglia in human and mouse GBM tumors and that high TREM2 expression correlates with poor prognosis in patients with GBM. TREM2 loss of function in human macrophages and mouse myeloid cells increased interferon-γ-induced immunoactivation, proinflammatory polarization, and tumoricidal capacity. In orthotopic mouse GBM models, mice with chronic and acute Trem2 loss of function exhibited decreased tumor growth and increased survival. Trem2 inhibition reprogrammed myeloid phenotypes and increased programmed cell death protein 1 (PD-1)+CD8+ T cells in the TME. Last, Trem2 deficiency enhanced the effectiveness of anti-PD-1 treatment, which may represent a therapeutic strategy for patients with GBM.

Expression of O-glycosylated oncofetal fibronectin in alternatively activated human macrophages

Macrophage (Mϕ) polarization is an essential phenomenon for the maintenance of homeostasis and tissue repair, and represents the event by which Mϕ reach divergent functional phenotypes as a result to specific stimuli and/or microenvironmental signals. Mϕ can be polarized into two main phenotypes, M1 or classically activated and M2 or alternatively activated. These two categories diverge in many aspects, such as secreted cytokines, markers of cell surface, and biological functions. Over the last 10 years, many potential markers have been proposed for both M1 and M2 human Mϕ. However, there is scarce information regarding the glycophenotype adopted by these cells. Here, we show that M2- but not M1-polarized Mϕ expresses high levels of an unusual glycoform of fibronectin (FN), named O-glycosylated oncofetal FN (onf-FN), found in fetal/cancer cells, but not in healthy tissues. The onf-FN expression was confirmed in vitro by Western blot and real-time RT-qPCR in primary and cell line monocyte-derived Mϕ. onf-FN was induced by IL-4 and IL-13, but not by pro-inflammatory stimuli (LPS and INF-γ). RNA and protein analysis clearly demonstrated that it is specifically associated with the M2 polarization. In conclusion, we show by the first time that O-glycosylated onf-FN is expressed by M2-polarized Mϕ.

In Vitro Methods to Evaluate Macrophage Polarization and Function in Cancer

Tumor-associated macrophages (TAMs) play a key immunosuppressive role that limits the ability of the immune system to fight cancer and hinder the anti-tumoral efficacy of most treatments currently applied in the clinic. However, a key feature of macrophages is their phenotypical and functional plasticity, which called their attention as promising targets for therapeutic intervention based on their elimination or reprogramming toward M1-like cytotoxic effector cells, with anti-tumor functions. This polarization status of macrophages can be studied in terms of molecular markers and functional activities, using an appropriate combination of experimental methodologies, both in vitro and in vivo. Here we focus on describing in vitro protocols to isolate primary monocytes from buffy coats and to study macrophage phenotype and function, after exposure to new therapies, by a combination of flow cytometry, RT-PCR, and ELISA analysis. We also provide the methodology to evaluate in vitro the cytotoxic activity of treated macrophages toward cancer cells.

Diversity of immune checkpoints in cancer immunotherapy

Finding effective treatments for cancer remains a challenge. Recent studies have found that the mechanisms of tumor evasion are becoming increasingly diverse, including abnormal expression of immune checkpoint molecules on different immune cells, in particular T cells, natural killer cells, macrophages and others. In this review, we discuss the checkpoint molecules with enhanced expression on these lymphocytes and their consequences on immune effector functions. Dissecting the diverse roles of immune checkpoints in different immune cells is crucial for a full understanding of immunotherapy using checkpoint inhibitors.

Effect of M2-like macrophages of the injured-kidney cortex on kidney cancer progression

Chronic kidney disease (CKD) affects kidney cancer patients' mortality. However, the underlying mechanism remains unknown. M2-like macrophages have pro-tumor functions, also exist in injured kidney, and promote kidney fibrosis. Thus, it is suspected that M2-like macrophages in injured kidney induce the pro-tumor microenvironment leading to kidney cancer progression. We found that M2-like macrophages present in the injured kidney promoted kidney cancer progression and induced resistance to anti-PD1 antibody through its pro-tumor function and inhibition of CD8⁺ T cell infiltration. RNA-seq revealed Slc7a11 was upregulated in M2-like macrophages. Inhibition of Slc7a11 with sulfasalazine inhibited the pro-tumor function of M2-like macrophages and synergized with anti-PD1 antibody. Moreover, SLC7A11-positive macrophages were associated with poor prognosis among kidney cancer patients. Collectively, this study dissects the characteristic microenvironment in the injured kidney that contributed to kidney cancer progression and anti-PD1 antibody resistance. This insight offers promising combination therapy with anti-PD1 antibody and macrophage targeted therapy.

Cancer Metastasis and Treatment Resistance: Mechanistic Insights and Therapeutic Targeting of Cancer Stem Cells and the Tumor Microenvironment

Cancer metastasis and treatment resistance are the main causes of treatment failure and cancer-related deaths. Their underlying mechanisms remain to be fully elucidated and have been attributed to the presence of cancer stem cells (CSCs)-a small population of highly tumorigenic cancer cells with pluripotency and self-renewal properties, at the apex of a cellular hierarchy. CSCs drive metastasis and treatment resistance and are sustained by a dynamic tumor microenvironment (TME). Numerous pathways mediate communication between CSCs and/or the surrounding TME. These include a paracrine renin-angiotensin system and its convergent signaling pathways, the immune system, and other signaling pathways including the Notch, Wnt/β-catenin, and Sonic Hedgehog pathways. Appreciation of the mechanisms underlying metastasis and treatment resistance, and the pathways that regulate CSCs and the TME, is essential for developing a durable treatment for cancer. Pre-clinical and clinical studies exploring single-point modulation of the pathways regulating CSCs and the surrounding TME, have yielded partial and sometimes negative results. This may be explained by the presence of uninhibited alternative signaling pathways. An effective treatment of cancer may require a multi-target strategy with multi-step inhibition of signaling pathways that regulate CSCs and the TME, in lieu of the long-standing pursuit of a 'silver-bullet' single-target approach.

Transcriptomic Profiling of Breast Cancer Cells Induced by Tumor-Associated Macrophages Generates a Robust Prognostic Gene Signature

Breast cancer, one of the most prevalent neoplasms in the world, continues attracting worldwide attention. Macrophage, as the most abundant non-malignant cell in tumor, plays critical roles in both immune surveillance and tumorigenesis and has become a cell target of immunotherapy. Among all macrophages, tumor-associated macrophage (TAM) is regarded as the main force to promote tumorigenesis. To get an overall view of its impact on breast cancer, we employed a simplified and indirect coculturing cell model followed by RNA-sequencing to detect cancer cell's transcriptomic response induced by TAM and a prognostic gene signature was constructed based on it. Evidence from both cell models and clinical samples strengthened TAM's full-dimensional impact on breast cancer, involved in almost all known signal pathways dysregulated during tumorigenesis from transcription, translation and molecule transport to immune-related pathways. Consequently, the gene signature developed from these genes was tested to be powerful in prognostic prediction and associated with various clinical and biological features of breast cancer. Our study presented a more complete view of TAM's impact on breast cancer, which strengthened its role as an important therapy target. A 45-gene signature from the TAM-regulated genes was developed and shown potential in clinical application.

Crosstalk between Tumor-Associated Macrophages and MicroRNAs: A Key Role in Tumor Microenvironment

As an in-depth understanding of immunotherapy continues to grow, current anticancer therapy research is increasingly focused on the tumor microenvironment (TME). MicroRNAs (miRNAs) play crucial roles in the regulation of genetic information and expression and mediate interactions between tumor cells and components in the TME, such as tumor-associated macrophages (macrophages). Macrophages are abundant in the TME, and their different polarization directions can promote or inhibit tumor growth and progression. By regulating biological behaviors, such as macrophage recruitment, infiltration, and polarization, miRNAs can affect various molecular pathways to regulate tumor progression and treatment response. In this review, we discuss in detail the effects of macrophages on tumors and the multifaceted effects of miRNAs on macrophages. We also discuss the potential clinical applications and prospects of targeted therapy based on miRNAs, novel clinical biomarkers, and drug delivery systems.

EPSTI1 as an immune biomarker predicts the prognosis of patients with stage III colon cancer

Objective

The poor prognosis and heterogeneity of stage III colon cancer (CC) suggest the need for more prognostic biomarkers. The tumor microenvironment (TME) plays a crucial role in tumor progression. We aimed to explore novel immune infiltration-associated molecules that serve as potential prognostic and therapeutic targets.

Methods

TME immune scores were calculated using “TMEscore” algorithm. Differentially expressed genes between the high and low TME immune score groups were identified and further investigated through a protein-protein interaction network and the Molecular Complex Detection algorithm. Cox regression, meta-analysis and immunohistochemistry were applied to identify genes significantly correlated with relapse-free survival (RFS). We estimated immune infiltration using three different algorithms (TIMER 2.0, CIBERSORTx, and TIDE). Single-cell sequencing data were processed by Seurat software.

Results

Poor RFS was observed in the low TME immune score groups (log-rank P < 0.05). EPSTI1 was demonstrated to be significantly correlated with RFS (P < 0.05) in stage III CC. Meta-analysis comprising 547 patients revealed that EPSTI1 was a protective factor (HR = 0.79, 95% CI, 0.65-0. 96; P < 0.05)). More immune infiltrates were observed in the high EPSTI1 group, especially M1 macrophage and myeloid dendritic cell infiltration (P < 0.05).

Conclusion

The TME immune score is positively associated with better survival outcomes. EPSTI1 could serve as a novel immune prognostic biomarker for stage III CC.

Oncofetal reprogramming in tumour development and progression

Embryonic development is characterized by rapidly dividing cells, cellular plasticity and a highly vascular microenvironment. These features are similar to those of tumour tissue, in that malignant cells are characterized by their ability to proliferate and exhibit cellular plasticity. The tumour microenvironment also often includes immunosuppressive features. Reciprocal communication between various cellular subpopulations enables fetal and tumour tissues to proliferate, migrate and escape immune responses. Fetal-like reprogramming has been demonstrated in the tumour microenvironment, indicating extraordinary cellular plasticity and bringing an additional layer of cellular heterogeneity. More importantly, some of these features are also present during inflammation. This Perspective discusses the similarity between embryogenesis, inflammation and tumorigenesis, and describes the mechanisms of oncofetal reprogramming that enable tumour cells to escape from immune responses, promoting tumour growth and metastasis.

BRAFV600E Expression in Thyrocytes Causes Recruitment of Immunosuppressive STABILIN-1 Macrophages

Simple Summary

Incidence of thyroid cancer, including papillary thyroid cancer, is rapidly increasing. Oncogenes, such as the BRAF^V600E, have been identified, and their effect on thyroid cancer cells have been studied in vitro and in mouse models. What is less understood is the impact of these mutations on thyroid cancer microenvironment and, in turn, the effect of changes in the microenvironment on tumor progression. We investigated the modifications in the cellular composition of thyroid cancer microenvironment using an inducible mouse model. We focused on a subpopulation of macrophages, expressing the STABILIN-1 protein, recruited in the thyroid tumor microenvironment following BRAF^V600E expression. CRISPR/Cas9 genetic inactivation of Stablin-1 did not change macrophage recruitment but highlighted the immunosuppressive role of STABILIN-1-expressing macrophages. The identification of a similar subpopulation of STABILIN-1 macrophages in human thyroid diseases supports a conserved role for these macrophages and offers an opportunity for intervention.

Abstract

Papillary thyroid carcinoma (PTC) is the most frequent histological subtype of thyroid cancers (TC), and BRAF^V600E genetic alteration is found in 60% of this endocrine cancer. This oncogene is associated with poor prognosis, resistance to radioiodine therapy, and tumor progression. Histological follow-up by anatomo-pathologists revealed that two-thirds of surgically-removed thyroids do not present malignant lesions. Thus, continued fundamental research into the molecular mechanisms of TC downstream of BRAF^V600E remains central to better understanding the clinical behavior of these tumors. To study PTC, we used a mouse model in which expression of BRAF^V600E was specifically switched on in thyrocytes by doxycycline administration. Upon daily intraperitoneal doxycycline injection, thyroid tissue rapidly acquired histological features mimicking human PTC. Transcriptomic analysis revealed major changes in immune signaling pathways upon BRAF^V600E induction. Multiplex immunofluorescence confirmed the abundant recruitment of macrophages, among which a population of LYVE-1+/CD206+/STABILIN-1+ was dramatically increased. By genetically inactivating the gene coding for the scavenger receptor STABILIN-1, we showed an increase of CD8+ T cells in this in situ BRAF^V600E-dependent TC. Lastly, we demonstrated the presence of CD206+/STABILIN-1+ macrophages in human thyroid pathologies. Altogether, we revealed the recruitment of immunosuppressive STABILIN-1 macrophages in a PTC mouse model and the interest to further study this macrophage subpopulation in human thyroid tissues.

GPNMB: a potent inducer of immunosuppression in cancer

The immune system is comprised of both innate and adaptive immune cells, which, in the context of cancer, collectively function to eliminate tumor cells. However, tumors can actively sculpt the immune landscape to favor the establishment of an immunosuppressive microenvironment, which promotes tumor growth and progression to metastatic disease. Glycoprotein-NMB (GPNMB) is a transmembrane glycoprotein that is overexpressed in a variety of cancers. It can promote primary tumor growth and metastasis, and GPNMB expression correlates with poor prognosis and shorter recurrence-free survival in patients. There is growing evidence supporting an immunosuppressive role for GPNMB in the context of malignancy. This review provides a description of the emerging roles of GPNMB as an inducer of immunosuppression, with a particular focus on its role in mediating cancer progression by restraining pro-inflammatory innate and adaptive immune responses.

Dissecting the treatment-naive ecosystem of human melanoma brain metastasis

Melanoma brain metastasis (MBM) frequently occurs in patients with advanced melanoma; yet, our understanding of the underlying salient biology is rudimentary. Here, we performed single-cell/nucleus RNA-seq in 22 treatment-naive MBMs and 10 extracranial melanoma metastases (ECMs) and matched spatial single-cell transcriptomics and T cell receptor (TCR)-seq. Cancer cells from MBM were more chromosomally unstable, adopted a neuronal-like cell state, and enriched for spatially variably expressed metabolic pathways. Key observations were validated in independent patient cohorts, patient-derived MBM/ECM xenograft models, RNA/ATAC-seq, proteomics, and multiplexed imaging. Integrated spatial analyses revealed distinct geography of putative cancer immune evasion and evidence for more abundant intra-tumoral B to plasma cell differentiation in lymphoid aggregates in MBM. MBM harbored larger fractions of monocyte-derived macrophages and dysfunctional TOX+CD8+ T cells with distinct expression of immune checkpoints. This work provides comprehensive insights into MBM biology and serves as a foundational resource for further discovery and therapeutic exploration.

The Role of Myeloid Cells in GBM Immunosuppression

Gliomas are intrinsic brain tumors that originate from glial cells. Glioblastoma (GBM) is the most aggressive glioma type and resistant to immunotherapy, mainly due to its unique immune environment. Dimensional data analysis reveals that the intra-tumoral heterogeneity of immune cell populations in the glioma microenvironment is largely made up of cells of myeloid lineage. Conventional therapies of combined surgery, chemotherapy and radiotherapy have achieved limited improvements in the prognosis of glioma patients, as myeloid cells are prominent mediators of immune and therapeutic responses—like immunotherapy resistance—in glioma. Myeloid cells are frequently seen in the tumor microenvironment (TME), and they are polarized to promote tumorigenesis and immunosuppression. Reprogramming myeloid cells has emerged as revolutionary, new types of immunotherapies for glioma treatment. Here we detail the current advances in classifying epigenetic, metabolic, and phenotypic characteristics and functions of different populations of myeloid cells in glioma TME, including myeloid-derived suppressor cells (MDSCs), glioma-associated microglia/macrophages (GAMs), glioma-associated neutrophils (GANs), and glioma-associated dendritic cells (GADCs), as well as the mechanisms underlying promotion of tumorigenesis. The final goal of this review will be to provide new insights into novel therapeutic approaches for specific targeting of myeloid cells to improve the efficacy of current treatments in glioma patients.

Roles and new Insights of Macrophages in the Tumor Microenvironment of Thyroid Cancer

Although most thyroid cancers have a good and predictable prognosis, the anaplastic, medullary, and refractory thyroid cancers still prone to recurrence and metastasis, resulting in poor prognosis. Although a number of newly developed targeted therapies have begun to be indicated for the above types of thyroid cancer in recent years, their ability to improve overall survival remain hindered by low efficacy. As the largest component of immune cells in tumor microenvironment, tumor-associated macrophages play a key role in the invasion and metastasis of thyroid cancer. There is much evidence that the immune system, tumor microenvironment and cancer stem cell interactions may revolutionize traditional therapeutic directions. Tumor-associated macrophages have been extensively studied in a variety of tumors, however, research on the relationship between thyroid cancer and macrophages is still insufficient. In this review, we summarize the functions of tumor-associated macrophages in different types of thyroid cancer, their cytokines or chemokines effect on thyroid cancer and the mechanisms that promote tumor proliferation and migration. In addition, we discuss the mechanisms by which tumor-associated macrophages maintain the stemness of thyroid cancer and potential strategies for targeting tumor-associated macrophages to treat thyroid cancer.

Ligand-activated PPARδ expression promotes hepatocellular carcinoma progression by regulating the PI3K-AKT signaling pathway

Background

Peroxisome proliferator-activated receptor-beta/delta (PPARδ) was considered as the key regulator involved in the evolution of various tumors. Given that PPARδ potential role in hepatocellular carcinoma (HCC) is still obscure, we comprehensively assessed its expression pattern, prognosis, functions and correlation with tumor microenvironment in HCC using public database data and in vitro studies.

Methods

Transcriptional data and clinical data in the TCGA and GEO database were analyzed in R software. Quantitative real-time polymerase chain reaction (qRT-PCR), western blotting and immunohistochemistry were used to detect the expression level of related RNA and proteins. The malignant biological characteristics were explored by cell counting Kit-8 (CCK8), 5-Ethynyl-2ʹ-deoxyuridine (EdU) assay and wound healing assay.

Results

Our results illustrated that PPARδ expression was significantly higher in HCC tissues and HCC cell lines. Elevated expression of PPARδ suggested poor clinical staging and prognosis in HCC. Ligand-activated PPARδ expression promoted the proliferation and invasion of HCC cells via PDK1/AKT/GSK3β signaling pathway. The expression of PPARδ was closely related to the HCC tumor microenvironment.

Conclusions

PPARδ plays an important part in HCC progression, penetrating investigation of the related regulatory mechanism may shed light upon further biological and pharmacological value.

miR-182 targeting reprograms tumor-associated macrophages and limits breast cancer progression

The protumor roles of alternatively activated (M2) tumor-associated macrophages (TAMs) have been well established, and macrophage reprogramming is an important therapeutic goal. However, the mechanisms of TAM polarization remain incompletely understood, and effective strategies for macrophage targeting are lacking. Here, we show that miR-182 in macrophages mediates tumor-induced M2 polarization and can be targeted for therapeutic macrophage reprogramming. Constitutive miR-182 knockout in host mice and conditional knockout in macrophages impair M2-like TAMs and breast tumor development. Targeted depletion of macrophages in mice blocks the effect of miR-182 deficiency in tumor progression while reconstitution of miR-182-expressing macrophages promotes tumor growth. Mechanistically, cancer cells induce miR-182 expression in macrophages by TGFβ signaling, and miR-182 directly suppresses TLR4, leading to NFκb inactivation and M2 polarization of TAMs. Importantly, therapeutic delivery of antagomiR-182 with cationized mannan-modified extracellular vesicles effectively targets macrophages, leading to miR-182 inhibition, macrophage reprogramming, and tumor suppression in multiple breast cancer models of mice. Overall, our findings reveal a crucial TGFβ/miR-182/TLR4 axis for TAM polarization and provide rationale for RNA-based therapeutics of TAM targeting in cancer.

Acquired resistance for immune checkpoint inhibitors in cancer immunotherapy: challenges and prospects

Drug resistance has become an obstacle to the further development of immunotherapy in clinical applications and experimental studies. In the current review, the acquired resistance to immunotherapy was examined. The mechanisms of acquired resistance were based on three aspects as follows: The change of the tumor functions, the upregulated expression of inhibitory immune checkpoint proteins, and the effects of the tumor microenvironment. The combined use of immunotherapy and other therapies is performed to delay acquired resistance. A comprehensive understanding of acquired drug resistance may provide ideas for solving this dilemma.