Tumor-associated macrophages: role in cancer development and therapeutic implications

ALOX5AP Predicts Poor Prognosis by Enhancing M2 Macrophages Polarization and Immunosuppression in Serous Ovarian Cancer Microenvironment

Background

Serous ovarian cancer (SOC) is a highly lethal gynecological malignancy with poor prognosis. Given the importance of the immune-related tumor microenvironment (TME) in ovarian cancer, investigating tumor-immune interactions and identifying novel prognostic and therapeutic targets in SOC is a promising avenue of research. ALOX5AP (Arachidonate 5-Lipoxygenase Activating Protein) is a key enzyme in converting arachidonic acid to leukotriene: a crucial immune-modulating lipid mediator. However, the role of ALOX5AP in SOC has yet to be studied.

Methods

ALOX5AP expression patterns across ovarian cancer and their normal tissue counterparts were cross-checked using public microarray and RNA-seq analyses and then validated in clinical samples by qRT-PCR. Kaplan-Meier survival analysis was performed in multiple independent SOC patient cohorts. Univariate and multivariate Cox regression analysis were then employed to identify clinical risk parameters associated with survival, and a genomic-clinicopathologic nomogram was built. Gene enrichment, immune infiltration, and immunosuppressor correlation analyses were then evaluated.

Results

ALOX5AP mRNA levels in SOC tissues were significantly upregulated compared to normal tissues. Elevated ALOX5AP was markedly associated with poor overall survival and progression-free survival in multiple SOC patient cohorts as well as with adverse clinicopathological features, including lymphatic invasion, unsatisfactory cytoreductive surgery, rapid relapse after primary treatment, and platinum non-responsiveness. A predictive nomogram, which integrated ALOX5AP expression and two independent prognosis factors (primary therapy outcome and tumor residual), was conducted to predict the 3-year and 5-year survival rate of SOC patients. Mechanistically, functional and pathway enrichment analyses revealed that ALOX5AP was primarily involved in immune response and regulation. Further exploration demonstrated that ALOX5AP was highly expressed in the immunoreactive subtype of ovarian cancer and closely related to immunocyte infiltration, especially M2 macrophage polarization. Additionally, ALOX5AP was enriched in the C4 (lymphocyte depleted) immune subtype of SOC and associated with crucial immune-repressive receptors in the tumor microenvironment at the genomic level.

Conclusions

ALOX5AP expression indicates a worse survival outcome and has the potential to be utilized as a prognostic predictor for SOC patients. Given the availability of well-studied ALOX5AP inhibitors, this study has immediate clinical implications for the exploitation of ALOX5AP as an immunotherapeutic target in SOC.

LncRNA LOC100129620 promotes osteosarcoma progression through regulating CDK6 expression, tumor angiogenesis, and macrophage polarization

Osteosarcoma is a malignant tumor with high mortality in children and adolescents. The mechanism of osteosarcoma metastasis is currently unclear. Abnormal expression of long non-coding RNA (lncRNA) plays an important role in tumor metastasis. We used bioinformatics to analyze the differences in gene expression between osteosarcoma in situ and osteosarcoma lung metastases. CCK-8 was used to detect the effect of lncRNA LOC100129620 on the proliferation of osteosarcoma cells. The effect of LOC100129620 on the invasion of osteosarcoma cells was assessed by Transwell assay. The regulatory effect of LOC100129620 on miR-335-3p was examined using RNA pull-down and luciferase reporter gene assays. The effect of LOC100129620 on the polarization of macrophages was detected by quantitative real-time fluorescent PCR. The results show that LOC100129620 can promote the proliferation and migration of osteosarcoma cells. LOC100129620 can promote the proliferation of osteosarcoma in vivo. LOC100129620 can bind to miR-335-3p and regulate its function. MiR-335-3p mediates the regulatory effects of LOC100129620 on CDK6. LOC100129620 promotes the formation of blood vessels and the polarization of macrophages. The LOC100129620/miR-335-3p/CDK6 signaling pathway promotes the metastasis of osteosarcoma by regulating the proliferation of osteosarcoma cells, angiogenesis, and macrophage polarization.

Prognostic Significance of Tumor-Associated Macrophages in Chondroblastoma and Their Association with Response to Adjuvant Radiotherapy

Objective

Chondroblastoma (CB) is a rare and locally growing cartilage-derived tumor. Currently, clinical implications of tumor-associated macrophages (TAMs) in CB remain unclear. In this study, we sought to analyze the relationship between TAM parameters (including densities of CD68+ and CD163+ cells as well as the CD163+/CD68+ ratio) and clinicopathological characteristics and survival of patients.

Methods

Immunohistochemistry was used to assess TAM subtypes for CD68 and CD163, as well as the expression levels of p53, CD34, and Ki-67 on tumor cells in 132 tissue specimens retrieved between July 2002 and April 2020. Then, TAM parameters were retrospectively analyzed for their associations with patient outcomes (local recurrence-free survival [LRFS] and overall survival [OS]) and clinicopathological features.

Results

TAM densities were significantly higher in axial chondroblastoma tissue than in extra-axial chondroblastoma tissue. Moreover, the number of CD163+ TAMs was positively correlated with tumor invasion of surrounding tissues and high expression of CD34 and Ki-67 on tumor cells, whereas CD163+ cell density and the CD163/CD68 ratio were negatively associated with patient response to adjuvant radiotherapy. Univariate Kaplan-Meier analysis revealed that the number of CD68+ and CD163+ lymphocytes was significantly associated with both LRFS and OS. Multivariate Cox regression analysis showed that CD163+ and CD68+ cell levels were independent prognostic factors of LRFS, while TAM data independently predicted OS. More importantly, in subgroup analysis based on three significant factors in univariate survival analysis (including tumor location, adjuvant radiotherapy, and surrounding tissue invasion by tumors), the TAM parameters still displayed good prognostic performance.

Conclusion

These data suggest that TAM may significantly affect the biological behavior of CB. We hypothesize that modulating the TAM level or polarization status in the microenvironment may be an effective approach for CB treatment.

Absent in melanoma 2-mediating M1 macrophages facilitate tumor rejection in renal carcinoma

Absent in melanoma 2 (AIM2) as an immune regulator for the regulation of tumor-associated macrophages (TAMs) function is unclear in tumor development. Here, the AIM2 function was investigated in TAMs-mediated malignant behaviors of renal carcinoma. The correlation analysis result showed that the AIM2 expression in TAMs was negatively correlated with the percentages of M2-like polarization phenotype in human or murine renal cancer specimens. By the cocultured assay with bone marrow-derived macrophages (BMDMs) and Renca cells, overexpression of AIM2 in macrophages enhanced the inflammasome activation and reversed the phenotype from M2 to M1. Compared with BMDMs-Ctrl cocultured group, BMDMs-AIM2 cocultured group showed reduced tumor cell proliferation and migration. The blockade of inflammasome activation by the inhibitor Ac-YVAD-CMK abrogated AIM2-mediated M1 polarization and the inhibition of tumor cell growth. To evaluate the therapeutic efficacy of AIM2-mediated M1 macrophages in vivo, BMDMs-AIM2 were intravenously injected into subcutaneous Renca-tumor mice. The results showed that the infiltration of M1 TAMs was increased and tumor growth was suppressed in BMDMs-AIM2-treated mice when compared with BMDMs-Ctrl-treat mice. Accordingly, the blockade of inflammasome activation reduced the anti-tumor activities of BMDMs-AIM2. Moreover, the lung metastases of renal carcinoma were suppressed by the administration of BMDMs-AIM2 accompanied with the reduced tumor foci. These results demonstrated that AIM2 enhanced TAMs polarization switch from anti-inflammatory M2 phenotypy to pro-inflammatory M1 through inflammasome signaling activation, thus exerting therapeutic intervention in renal carcinoma models. Our results provide a possible molecular mechanism for the modulation of TAMs polarization in tumor microenvironment and open a new potential therapeutic approach for renal cancer.

Inflammatory indexes in preoperative blood routine to predict early recurrence of hepatocellular carcinoma after curative hepatectomy

Background

The inflammation indexes in blood routine play an essential role in evaluating the prognosis of patients with hepatocellular carcinoma, but the effect on early recurrence has not been clarified. The study aimed to investigate the risk factors of early recurrence (within 2 years) and recurrence-free survival after curative hepatectomy and explore the role of inflammatory indexes in predicting early recurrence.

Methods

The baseline data of 161 patients with hepatocellular carcinoma were analyzed retrospectively. The optimal cut-off value of the inflammatory index was determined according to the Youden index. Its predictive performance was compared by the area under the receiver operating characteristic curve. Logistic and Cox regression analyses were used to determine the risk factors of early recurrence and recurrence-free survival.

Results

The area under the curve of monocyte to lymphocyte ratio (MLR) for predicting early recurrence was 0.700, which was better than systemic inflammatory response index (SIRI), neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR) and systemic immune-inflammatory index (SII). MLR, tumour size, tumour differentiation and BCLC stage are all risk factors for early recurrence and recurrence-free survival of HCC. Combining the above four risk factors to construct a joint index, the area under the curve for predicting early recurrence was 0.829, which was better than single MLR, tumour size, tumour differentiation and BCLC stage. Furthermore, with the increase of risk factors, the recurrence-free survival of patients is worse.

Conclusion

The combination of MLR and clinical risk factors is helpful for clinicians to identify high-risk patients with early recurrence and carry out active postoperative adjuvant therapy to improve the prognosis of patients.

Targeting macrophages in cancer immunotherapy

Immunotherapy is regarded as the most promising treatment for cancers. Various cancer immunotherapies, including adoptive cellular immunotherapy, tumor vaccines, antibodies, immune checkpoint inhibitors, and small-molecule inhibitors, have achieved certain successes. In this review, we summarize the role of macrophages in current immunotherapies and the advantages of targeting macrophages. To better understand and make better use of this type of cell, their development and differentiation characteristics, categories, typical markers, and functions were collated at the beginning of the review. Therapeutic strategies based on or combined with macrophages have the potential to improve the treatment efficacy of cancer therapies.

Effects of Medicinal Fungi-Derived β-Glucan on Tumor Progression

β-Glucans have been studied in animal species, from earthworms to humans. They form a heterogenous group of glucose polymers found in fungi, plants, bacteria, and seaweed. β-Glucans have slowly emerged as an important target for the recognition of pathogens. In the current review, we highlight the major roles of mushroom-derived β-glucans on cancer progression.

TFEB is a master regulator of tumor-associated macrophages in breast cancer

Background

Tumor-associated macrophages (TAMs) play key roles in the development of many malignant solid tumors including breast cancer. They are educated in the tumor microenvironment (TME) to promote tumor growth, metastasis, and therapy resistance. However, the phenotype of TAMs is elusive and how to regulate them for therapeutic purpose remains unclear; therefore, TAM-targeting therapies have not yet achieved clinical success. The purposes of this study were to examine the role of transcription factor EB (TFEB) in regulating TAM gene expression and function and to determine if TFEB activation can halt breast tumor development.

Methods

Microarrays were used to analyze the gene expression profile of macrophages (MΦs) in the context of breast cancer and to examine the impact of TFEB overexpression. Cell culture studies were performed to define the mechanisms by which TFEB affects MΦ gene expression and function. Mouse studies were carried out to investigate the impact of MΦ TFEB deficiency or activation on breast tumor growth. Human cancer genome data were analyzed to reveal the prognostic value of TFEB and its regulated genes.

Results

TAM-mimic MΦs display a unique gene expression profile, including significant reduction in TFEB expression. TFEB overexpression favorably modulates TAM gene expression through multiple signaling pathways. Specifically, TFEB upregulates suppressor of cytokine signaling 3 (SOCS3) and peroxisome proliferator-activated receptor γ (PPARγ) expression and autophagy/lysosome activities, inhibits NLRP3 (NLR Family Pyrin Domain Containing 3) inflammasome and hypoxia-inducible factor (HIF)-1α mediated hypoxia response, and thereby suppresses an array of effector molecules in TAMs including arginase 1, interleukin (IL)-10, IL-1β, IL-6 and prostaglandin E2. MΦ-specific TFEB deficiency promotes, while activation of TFEB using the natural disaccharide trehalose halts, breast tumor development by modulating TAMs. Analysis of human patient genome database reveals that expression levels of TFEB, SOCS3 and PPARγ are positive prognostic markers, while HIF-1α is a negative prognostic marker of breast cancer.

Conclusions

Our study identifies TFEB as a master regulator of TAMs in breast cancer. TFEB controls TAM gene expression and function through multiple autophagy/lysosome-dependent and independent pathways. Therefore, pharmacological activation of TFEB would be a promising therapeutic approach to improve the efficacy of existing treatment including immune therapies for breast cancer by favorably modulating TAM function and the TME.

Application of a three-dimensional (3D) breast cancer model to study macrophage polarization

Knowledge of the tumor microenvironment is crucial for developing an effective strategy to treat cancer. Recently, anticancer therapies targeting macrophages have been intensively investigated. Increased understanding of the importance of the tumor microenvironment has led to the development of three-dimensional (3D) in vitro tumor models. However, established techniques for studying tumor-associated macrophages in vitro are limited. We have previously characterized a 3D breast cancer model consisting of breast cancer cells and fibroblasts cocultured on a silk scaffold. In the present study, the influence of this model on macrophage polarization was investigated. The expression of macrophage markers was studied using reverse transcription-quantitative PCR and flow cytometry. The activity of nitric oxide synthase and arginase in macrophages was also measured. The presented model appeared to induce the polarization of macrophages towards an M2 phenotype. In this 3D tumor model, the in vivo behavior of macrophages could be reproduced. This model may be beneficial for the study of tumor biology and for screening drugs.

Adaptive Mechanisms of Tumor Therapy Resistance Driven by Tumor Microenvironment

Cancer is a disease which frequently has a poor prognosis. Although multiple therapeutic strategies have been developed for various cancers, including chemotherapy, radiotherapy, and immunotherapy, resistance to these treatments frequently impedes the clinical outcomes. Besides the active resistance driven by genetic and epigenetic alterations in tumor cells, the tumor microenvironment (TME) has also been reported to be a crucial regulator in tumorigenesis, progression, and resistance. Here, we propose that the adaptive mechanisms of tumor resistance are closely connected with the TME rather than depending on non-cell-autonomous changes in response to clinical treatment. Although the comprehensive understanding of adaptive mechanisms driven by the TME need further investigation to fully elucidate the mechanisms of tumor therapeutic resistance, many clinical treatments targeting the TME have been successful. In this review, we report on recent advances concerning the molecular events and important factors involved in the TME, particularly focusing on the contributions of the TME to adaptive resistance, and provide insights into potential therapeutic methods or translational medicine targeting the TME to overcome resistance to therapy in clinical treatment.

MAPKAP Kinase-2 Drives Expression of Angiogenic Factors by Tumor-Associated Macrophages in a Model of Inflammation-Induced Colon Cancer

Chronic inflammation increases the risk for colorectal cancer through a variety of mechanisms involving the tumor microenvironment. MAPK-activated protein kinase 2 (MK2), a major effector of the p38 MAPK stress and DNA damage response signaling pathway, and a critical regulator of pro-inflammatory cytokine production, has been identified as a key contributor to colon tumorigenesis under conditions of chronic inflammation. We have previously described how genetic inactivation of MK2 in an inflammatory model of colon cancer results in delayed tumor progression, decreased tumor angiogenesis, and impaired macrophage differentiation into a pro-tumorigenic M2-like state. The molecular mechanism responsible for the impaired angiogenesis and tumor progression, however, has remained contentious and poorly defined. Here, using RNA expression analysis, assays of angiogenesis factors, genetic models, in vivo macrophage depletion and reconstitution of macrophage MK2 function using adoptive cell transfer, we demonstrate that MK2 activity in macrophages is necessary and sufficient for tumor angiogenesis during inflammation-induced cancer progression. We identify a critical and previously unappreciated role for MK2-dependent regulation of the well-known pro-angiogenesis factor CXCL-12/SDF-1 secreted by tumor associated-macrophages, in addition to MK2-dependent regulation of Serpin-E1/PAI-1 by several cell types within the tumor microenvironment.

Exosomal miR-487a derived from m2 macrophage promotes the progression of gastric cancer

Tumor-associated macrophages contribute to cell growth, development, and metastasis in various cancers. However, the underlying mechanisms of M2 macrophage that modulate the progression of gastric cancer (GC) remain largely unknown. In this study, we detected the ratio of macrophages in GC tissues and found that the proportion of M2 macrophages was increased in GC tissues. We then co-cultured GC cells with M1 and M2 macrophages, respectively, and then assessed cell proliferation and tumorigenicity of GC cells by MTT and colony formation assay. The results indicated that M2 macrophages promoted the proliferation of GC cells, but M1 not. Besides, GW4869, an exosomes inhibitor, reduced the effects induced by M2 macrophage. Then, we isolated and identified exosomes derived from M1 and M2 macrophage, and confirmed that the exosomes could be taken up by GC cells. We demonstrated that M2 macrophage-exosomes could induce the proliferation and tumorigenesis in vitro and in vivo. Moreover, miR-487a was enriched in M2 macrophage-exosomes and further determined that miR-487a exert the functions by targeting TIA1. In conclusion, exosomal miR-487a derived from M2 macrophage promotes the proliferation and tumorigenesis in gastric cancer, and the novel findings might be helpful to the development of novel diagnostic and therapeutic methods in GC.

An Overview of Advances in Cell-Based Cancer Immunotherapies Based on the Multiple Immune-Cancer Cell Interactions

Tumors have a complex ecosystem in which behavior and fate are determined by the interaction of diverse cancerous and noncancerous cells at local and systemic levels. A number of studies indicate that various immune cells participate in tumor development (Fig. 1). In this review, we will discuss interactions among T lymphocytes (T cells), B cells, natural killer (NK) cells, dendritic cells (DCs), tumor-associated macrophages (TAMs), neutrophils, and myeloid-derived suppressor cells (MDSCs). In addition, we will touch upon attempts to either use or block subsets of immune cells to target cancer.

Tumor-Associated Macrophages: New Horizons for Pituitary Adenoma Researches

Macrophages are one of the most common infiltrating immune cells and an essential component of tumor microenvironment. Macrophages and the soluble cytokines and chemokines produced play an important role in tumorigenesis, progression, invasion and metastasis in solid tumors. Despite the multiple studies in other solid tumors, there is little known about macrophages in pituitary adenomas. Recently, studies about pituitary adenoma-infiltrated macrophages have been emerging, including the immunohistochemical and immunophenotypic analysis of the pituitary adenomas and further studies into the mechanism of the crosstalk between macrophages and tumor cells in vivo and in vitro. These studies have offered us new insights into the polarization of macrophages and its role in tumorigenesis, progression and invasion of pituitary adenomas. This review describes the advances in the field of pituitary adenoma-infiltrated macrophages and the prospect of targeting macrophages as cancer therapy in pituitary adenoma.

Systemic Inflammation Response Index Is a Predictor of Poor Survival in Locally Advanced Nasopharyngeal Carcinoma: A Propensity Score Matching Study

Introduction

Nasopharyngeal carcinoma (NPC) is a common malignancy in China and known prognostic factors are limited. In this study, neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), systemic immune inflammation index (SII), and systemic inflammation response index (SIRI) were evaluated as prognostic factors in locally advanced NPC patients.

Materials and Methods

NPC patients who received curative radiation or chemoradiation between January 2012 and December 2015 at the Second Xiangya Hospital were retrospectively reviewed, and a total of 516 patients were shortlisted. After propensity score matching (PSM), 417 patients were eventually enrolled. Laboratory and clinical data were collected from the patients' records. Receiver operating characteristic curve analysis was used to determine the optimal cut-off value. Survival curves were analyzed using the Kaplan-Meier method. The Cox proportional hazard model was used to identify prognostic variables.

Results

After PSM, all basic characteristics between patients in the high SIRI group and low SIRI group were balanced except for sex (p=0.001) and clinical stage (p=0.036). Univariate analysis showed that NLR (p=0.001), PLR (p=0.008), SII (p=0.001), and SIRI (p<0.001) were prognostic factors for progression-free survival (PFS) and overall survival (OS). However, further multivariate Cox regression analysis showed that only SIRI was an independent predictor of PFS and OS (hazard ratio (HR):2.83; 95% confidence interval (CI): 1.561-5.131; p=0.001, HR: 5.19; 95% CI: 2.588-10.406; p<0.001), respectively.

Conclusion

Our findings indicate that SIRI might be a promising predictive indicator of locally advanced NPC patients.

Astragaloside IV antagonizes M2 phenotype macrophage polarization-evoked ovarian cancer cell malignant progression by suppressing the HMGB1-TLR4 axis

Macrophages are the most abundant cells in tumor stroma and their polarization within tumor microenvironment exert the key roles in tumorigenesis. Astragaloside IV is a natural extract from traditional Chinese herbal Radix Astragali, and fulfills pleiotropic function in several cancers. Nevertheless, its function in ovarian cancer microenvironment remains elusive. In the present research, astragaloside IV exhibited little cytotoxicity within a certain dose range in THP-1 cells. Moreover, astragaloside IV suppressed the ratio of CD14⁺CD206⁺ cells in IL-4/IL-13-treated THP-1 macrophages and transcripts of M2 macrophage markers (including CD206, CCL24, PPARγ, Arg-1, IL-10), indicating the inhibitory effects of astragaloside IV on IL-4/IL-13-induced macrophage M2 polarization. Intriguingly, astragaloside IV antagonized M2 macrophages coculture-evoked cell proliferation, invasion and migration in ovarian cancer cells. During this process, administration with astragaloside IV restrained the high expression of high-mobility group box1 (HMGB1) and TLR4 in macrophages co-cultured with ovarian cancer cells, concomitant with decreases in release of M2 marker TGF-β, MMP-9 and IL-10. Moreover, targeting the HMGB1 signaling reversed M2 macrophages-induced ovarian cancer cell proliferation, invasion and migration. Noticeably, exogenous HMGB1 overturned the inhibitory efficacy of astragaloside IV against macrophage M2 polarization-evoked malignant potential in ovarian cancer cells. Together, these findings suggest that astragaloside IV may protect against M2 macrophages-evoked malignancy in ovarian cancer cells by suppressing the HMGB1-TLR4 signaling. Therefore, astragaloside may alleviate the progression of ovarian cancer by regulating macrophage M2 polarization within tumor microenvironment, implying a promising therapeutic strategy against ovarian cancer.

Integrating Tumor Stroma Biomarkers With Clinical Indicators for Colon Cancer Survival Stratification

The tumor stroma plays an important role in tumor progression and chemotherapeutic resistance; however, its role in colon cancer (CC) survival prognosis remains to be investigated. Here, we identified tumor stroma biomarkers and evaluated their role in CC prognosis stratification. Four independent datasets containing a total of 1,313 patients were included in this study and were divided into training and testing sets. Stromal scores calculated using the estimation of stromal and immune cells in malignant tumors using expression data (ESTIMATE) algorithm were used to assess the tumor stroma level. Kaplan-Meier curves and the log-rank test were used to identify relationships between stromal score and prognosis. Tumor stroma biomarkers were identified by cross-validation of multiple datasets and bioinformatics methods. Cox proportional hazards regression models were constructed using four prognosis factors (age, tumor stage, the ESTIMATE stromal score, and the biomarker stromal score) in different combinations for prognosis prediction and compared. Patients with high stromal scores had a lower overall survival rate (p = 0.00016), higher risk of recurrence (p < 0.0001), and higher probability of chemotherapeutic resistance (p < 0.0001) than those with low scores. We identified 16 tumor stroma biomarkers and generated a new prognosis indicator termed the biomarker stromal score (ranging from 0 to 16) based on their expression levels. Its addition to an age/tumor stage-based model significantly improved prognosis prediction accuracy. In conclusion, the tumor stromal score is significantly negatively associated with CC survival prognosis, and the new tumor stroma indicator can improve CC prognosis stratification.

G-CSF and G-CSFR Induce a Pro-Tumorigenic Macrophage Phenotype to Promote Colon and Pancreas Tumor Growth

Tumor-associated macrophages (TAMs) in the gastrointestinal tumor microenvironment (TME) are known to polarize into populations exhibiting pro- or anti-tumoral activity in response to stimuli such as growth factors and cytokines. Our previous work has recognized granulocyte colony-stimulating factor (G-CSF) as a cytokine capable of influencing immune cells of the TME exhibiting pro-tumoral activity. Here, we aimed to focus on how G-CSF regulates TAM phenotype and function and the effects on gastrointestinal (GI) tumor progression. Thus, wildtype (WT) and G-CSFR^-/- macrophages were examined for cytokine production, gene expression, and transcription factor activity. Adoptive transfer of WT or G-CSFR^-/- macrophages into tumor-bearing mice was performed to study their influence in the progression of colon (MC38) and pancreatic (PK5L1940) tumor mouse models. Finally, the difference in cytotoxic potential between WT and G-CSFR^-/- macrophages was examined both in vitro and in vivo. Our results indicate that G-CSF promotes increased IL-10 production and decreased IL-12 production, which was reversed in G-CSFR^-/- macrophages for a pro-inflammatory phenotype. Furthermore, G-CSFR^-/- macrophages were characterized by higher levels of NOS2 expression and NO production, which led to greater tumor related cytotoxicity both in vitro and in vivo. Our results suggest that in the absence of G-CSFR, macrophage-related tumor cytotoxicity was amplified. These findings, along with our previous reports, pinpoint G-CSF /G-CSFR as a prominent target for possible clinical applications that aim to control the TME and the GI tumor progression.

Noninvasive Visualization of Obesity-Boosted Inflammation in Orthotopic Pancreatic Ductal Adenocarcinoma Using an Octapod Iron Oxide Nanoparticle

Tumor-associated macrophages (TAMs) are the most abundant immune cells in the tumor microenvironment and promote the progression of tumors, including pancreatic ductal adenocarcinoma (PDAC). Obesity is a metabolic disease and a significant factor that affects tumor immunity and immunotherapy, contributing to a poorer tumor prognosis. However, TAMs as the link between obesity and poorer tumor prognosis has been less addressed and remains unclear. The current study aimed to noninvasively determine the effect of obesity on TAMs in orthotopic PDAC animal models, leptin-deficient transgenic obese (ob/ob) mice. Iron oxide nanoparticles, Octapod-30, with ultra high r₂ values, were utilized for in vivo consecutive T₂-weighted MR imaging. After Octapod-30 injection, the T₂-weighted signal intensity of the tumor area of both lean wild-type (WT) and ob/ob mice decreased rapidly, and the signal intensity significantly decreased as early as 0.5 h after injection compared with preinjection. The signal intensity continually decreased until 2 h and sustained for 4 h. In addition, the quantified signal intensity in obese ob/ob mice bearing PDAC significantly decreased compared with that in lean WT mice. Further histopathological analysis demonstrated that CD68-marked TAMs were highly colocalized with Prussian blue-stained Octapod-30, which were significantly more infiltrated in the tumor tissue of ob/ob mice than in the WT group, in parallel with larger size of tumor, higher levels of Ki67-marked proliferation and CD31-marked angiogenesis. Our results suggested that obesity increased TAMs infiltration and Octopad-30 can rapidly noninvasively detect TAMs in vivo in orthotopic PDAC with high spatial resolution and temporal resolution. Furthermore, the application of ultra high r₂ octagonal iron oxide nanoparticles with powerful clinical conversion potential could allow noninvasive and efficient quantitative analysis of TAMs in PDAC with or without obesity, providing a promising inspection approach for early detection, treatment management, and efficacy evaluation of tumors for clinical application.

Epithelial-stromal communication via CXCL1-CXCR2 interaction stimulates growth of ovarian cancer cells through p38 activation

PURPOSE

Paracrine interactions with the stromal environment, including fibroblasts, may be important in the pathogenesis of ovarian cancer. Here, we evaluated the effect of conditioned media derived from ovarian fibroblasts (fibroblast-CMs) and their major cytokines on the growth of ovarian cancer cells, as well as the involvement of mitogen-activated protein kinases (MAPKs) and AKT in mediating this effect.

METHODS

Ovarian cancer cells were cultured in serum-free media (SF), or conditioned media of fibroblasts derived from normal ovary (CM1) and ovarian tumor tissue (CM2). Cell proliferation was measured by MTT assay. Phosphorylation of MAPKs and AKT was evaluated by Western blotting. Specific inhibitors of MAPKs and AKT were used to evaluate their respective involvement in mediating increased cell growth. Cytokine levels in fibroblast-CMs were measured using Luminex assays. Immunohistochemical staining was conducted for CXCL1, CXCR2 and phosphorylated p38 in primary ovarian tumors.

RESULTS

CM1 and CM2 significantly increased the growth of ovarian cancer cells relative to SF. In OVCAR3 and OVCAR4 cells, p38 phosphorylation was strongly induced by fibroblast-CMs, and pre-treatment with a p38 inhibitor prevented the growth increase induced by fibroblast-CMs. Fibroblasts secreted high levels of IL-6, IL-8, MCP1 and CXCL1. Treatment with only CXCL1 (1 μg/ml) increased cell growth and p38 phosphorylation. Treatment with a CXCR2 inhibitor effectively prevented p38 activation and cell growth induced by fibroblast-CMs. High expression of both CXCL1 and CXCR2 correlated with high expression of phosphorylated p38 in primary ovarian tumors.

CONCLUSIONS

From our data, we conclude that CXCL1 is a key factor derived from ovarian fibroblasts that is responsible for increased ovarian cancer cell growth in part through p38 activation. Phosphorylated p38 can be used as a biomarker to predict CXCL1-CXCR2 interaction in vivo.

Analyzing One Cell at a TIME: Analysis of Myeloid Cell Contributions in the Tumor Immune Microenvironment

Tumor-mediated regulation of the host immune system involves an intricate signaling network that results in the tumor's inherent survival benefit. Myeloid cells are central in orchestrating the mechanisms by which tumors escape immune detection and continue their proliferative programming. Myeloid cell activation has historically been classified using a dichotomous system of classical (M1-like) and alternative (M2-like) states, defining general pro- and anti-inflammatory functions, respectively. Explosions in bioinformatics analyses have rapidly expanded the definitions of myeloid cell pro- and anti-inflammatory states with different combinations of tissue- and disease-specific phenotypic and functional markers. These new definitions have allowed researchers to target specific subsets of disease-propagating myeloid cells in order to modify or arrest the natural progression of the associated disease, especially in the context of tumor-immune interactions. Here, we discuss the myeloid cell contribution to solid tumor initiation and maintenance, and strategies to reprogram their phenotypic and functional fate, thereby disabling the network that benefits tumor survival.

Identification of Novel Tumor-Microenvironment-Regulating Factor That Facilitates Tumor Immune Infiltration in Colon Cancer

Colon cancer is one of the most common malignancies causing death worldwide. It is well known that the cells of the tumor microenvironment contribute to the progression and prognosis of colon cancer. However, the gene alterations and potential remodeling mechanisms in the tumor microenvironment of colon cancer remain largely unknown. In this study, immune scores from the ESTIMATE algorithm were used to discriminate between patients with high or low immune-cell infiltration. There were 42 immune differentially expressed genes (DEGs) of prognostic value identified in this study. Among them, KCNJ5 is a key factor in promoting M2 macrophage recruitment and tumor immune infiltration in colon cancer. These findings may provide novel insights for decoding the complicated interplay between cancer cells and the tumor microenvironment as well as for developing new avenues for therapeutic intervention in colon cancer.

Redefining Tumor-Associated Macrophage Subpopulations and Functions in the Tumor Microenvironment

The immunosuppressive status of the tumor microenvironment (TME) remains poorly defined due to a lack of understanding regarding the function of tumor-associated macrophages (TAMs), which are abundant in the TME. TAMs are crucial drivers of tumor progression, metastasis, and resistance to therapy. Intra- and inter-tumoral spatial heterogeneities are potential keys to understanding the relationships between subpopulations of TAMs and their functions. Antitumor M1-like and pro-tumor M2-like TAMs coexist within tumors, and the opposing effects of these M1/M2 subpopulations on tumors directly impact current strategies to improve antitumor immune responses. Recent studies have found significant differences among monocytes or macrophages from distinct tumors, and other investigations have explored the existence of diverse TAM subsets at the molecular level. In this review, we discuss emerging evidence highlighting the redefinition of TAM subpopulations and functions in the TME and the possibility of separating macrophage subsets with distinct functions into antitumor M1-like and pro-tumor M2-like TAMs during the development of tumors. Such redefinition may relate to the differential cellular origin and monocyte and macrophage plasticity or heterogeneity of TAMs, which all potentially impact macrophage biomarkers and our understanding of how the phenotypes of TAMs are dictated by their ontogeny, activation status, and localization. Therefore, the detailed landscape of TAMs must be deciphered with the integration of new technologies, such as multiplexed immunohistochemistry (mIHC), mass cytometry by time-of-flight (CyTOF), single-cell RNA-seq (scRNA-seq), spatial transcriptomics, and systems biology approaches, for analyses of the TME.

The emerging landscape of circular RNAs in immunity: breakthroughs and challenges

Circular RNAs (circRNAs) are covalently linked RNAs that exhibit individual strand with a closed-loop framework compared with a conserving, steady and abundant linear counterpart. In recent years, as high-throughput sequencing advancement has been developing, functional circRNAs have been increasingly recognized, and more extensive analyses expounded their effect on different diseases. However, the study on the function of circRNAs in the immune system remains insufficient. This study discusses the basic principles of circRNAs regulation and the systems involved in physiology-related and pathology-related processes. The effect of circRNAs on immune regulation is elucidated. The ongoing development of circRNAs and basic immunology has multiplied their potential in treating diseases. Such perspective will summarize the status and effect of circRNAs on various immune cells in cancer, autoimmune diseases and infections. Moreover, this study will primarily expound the system of circRNAs in T lymphocytes, macrophages and other immune cells, which creates a novel perspective and lay a theoretical basis for treating diseases.

Cuban Brown Propolis Interferes in the Crosstalk between Colorectal Cancer Cells and M2 Macrophages

Tumor-associated macrophages (TAMs), primarily the M2 phenotype, are involved in the progression and metastasis of colorectal cancer (CRC). Cuban brown propolis (Cp) and its main component Nemorosone (Nem) displays an antiproliferative effect on different cancer cells, including CRC cell lines. However, whether Cp and Nem could exploit its effect on CRC cells by targeting their relationship with TAMs remains to be elucidated. In this study, we differentiated the human monocytic THP-1 cells to M2 macrophages and confirmed this transition by immunofluorescence (IF) staining, qRT-PCR and zymography. An MTT assay was performed to determine the effect of Cp and Nem on the viability of CRC HT-29 cells co-cultured with M2 macrophages. Furthermore, the migration and invasion abilities of HT-29 cells were determined by Transwell assays and the expression levels of epithelial–mesenchymal transition (EMT) markers were analyzed by IF staining. We demonstrated that Cp and Nem reduced the viability of M2 macrophages and, accordingly, the activity of the MMP-9 metalloprotein. Moreover, we demonstrated that M2 macrophages produce soluble factors that positively regulate HT-29 cell growth, migration and invasion. These M2-mediated effects were counteracted by Cp and Nem treatments, which also played a role in regulating the expression of the EMT markers E-cadherin and vimentin. Taken together, our results indicate that Nem contained in Cp interferes in the crosstalk between CRC cells and TAMs, by targeting M2 macrophages.

Role of the bone microenvironment in bone metastasis of malignant tumors - therapeutic implications

BACKGROUND

Bone is one of the most common sites for solid tumor metastasis. Bone metastasis of a malignant tumor seriously affects the quality of life and the overall survival of patients. Evidence has suggested that bone provides a favorable microenvironment that enables disseminated tumor cells to home, proliferate and colonize, leading to the formation of metastases. In the process of bone metastasis the bone microenvironment may be considered as an orchestra that plays a dissonant melody through blending (e.g. cross-talk between osteoclasts, osteoblasts and/or other cells), adding (e.g. a variety of biological factors) or taking away (e.g. blocking a specific pathway) players.

CONCLUSIONS

Here, we review the normal bone microenvironment, bone microenvironment-related factors that promote bone metastasis, as well as mechanisms underlying bone metastasis. In addition, we elude on directions for clinical bone metastasis management, focusing on potential therapeutic approaches to target bone microenvironment-related factors, including bisphosphonate, denosumab, CXCR4/CXCL12 antagonists and cathepsin K inhibitors.

Noncoding RNAs in oral premalignant disorders and oral squamous cell carcinoma

BACKGROUND

Oral squamous cell carcinoma (OSCC) has the highest mortality rate among all head and neck cancers and a relatively low five-year survival rate. Generally, the development of an oral mucosal malignancy represents a multistep process beginning with normal oral mucosa epithelium and culminating in OSCC after transitioning through intermediary oral premalignant disorders (OPMDs), during which dysplasia is often observed. Noncoding RNAs (ncRNAs) are RNAs that are not translated into proteins, but still can participate in regulating neoplastic cell behavior. Recently, data have emerged on the role of ncRNAs in the progression of oral mucosal malignant diseases, but the exact mechanisms through which ncRNAs are involved remain to be elucidated.

CONCLUSIONS

Knowledge on ncRNAs has added an extra layer of complexity to our understanding of the malignant progression of oral mucosal diseases. The identification of ncRNAs in multiple body fluids as biomarkers may provide new diagnostic options that can be used for the diagnosis and prognosis of OPMDs and OSCC, respectively. Despite overall advances that have been made in cancer treatment, the treatment options for OPMDs and OSCC are still limited. Several studies have shown that ncRNA-based treatment regimens may hold promise as alternative methods for treating OPMDs and OSCC. The use of ncRNAs as therapeutic agents, including miR-155, miR-34 and lncRNA HOTAIR, appear promising.

Systematic profiling of immune signatures identifies prognostic predictors in lung adenocarcinoma

PURPOSE

Lung adenocarcinoma (LUAD) is the predominant subtype of lung cancer, with increasing evidence showing clinical benefits of immunotherapy. However, a lack of integrated profiles of complex LUAD immune microenvironments hampers the application of immunotherapy, resulting in limited eligible patient populations as well as drug resistance problems. Here, we aimed to systematically profile the immune signatures of LUADs and to assess the role of the immune microenvironment in patient outcome.

METHODS

We systematically profiled the immune signatures of LUADs deposited in the TCGA and GEO databases using a total of 730 immune-related genes. Differential expression analysis was used to identify dysregulated genes. Univariate Cox analysis followed by robust likelihood-based survival analysis and multivariate Cox analysis were applied to construct an immune-related prognostic model.

RESULTS

We found that differentially expressed immune genes were mainly enriched in immune cell proliferation, migration, activation and the NF-κB and TNF signaling pathways. The 10-immune gene predictive model that we constructed could differentiate LUAD patients with different overall survival times in several datasets, with areas under the curve (AUCs) of 0.67, 0.69, 0.72 and 0.74. LUAD patients with high- or low-risk scores exhibited distinct immune cell compositions, which may explain the prognostic significance of our model.

CONCLUSIONS

Our results add to the current knowledge of immune processes in LUADs and underscore the critical role of the immune microenvironment in LUAD patient outcome.

Current insights into the metastasis of epithelial ovarian cancer - hopes and hurdles

BACKGROUND

Ovarian cancer is the most lethal gynecologic cancer and the fifth leading cause of cancer-related mortality in women worldwide. Despite various attempts to improve the diagnosis and therapy of ovarian cancer patients, the survival rate for these patients is still dismal, mainly because most of them are diagnosed at a late stage. Up to 90% of ovarian cancers arise from neoplastic transformation of ovarian surface epithelial cells, and are usually referred to as epithelial ovarian cancer (EOC). Unlike most human cancers, which are disseminated through blood-borne metastatic routes, EOC has traditionally been thought to be disseminated through direct migration of ovarian tumor cells to the peritoneal cavity and omentum via peritoneal fluid. It has recently been shown, however, that EOC can also be disseminated through blood-borne metastatic routes, challenging previous thoughts about ovarian cancer metastasis.

CONCLUSIONS

Here, we review our current understanding of the most updated cellular and molecular mechanisms underlying EOC metastasis and discuss in more detail two main metastatic routes of EOC, i.e., transcoelomic metastasis and hematogenous metastasis. The emerging concept of blood-borne EOC metastasis has led to exploration of the significance of circulating tumor cells (CTCs) as novel and non-invasive prognostic markers in this daunting cancer. We also evaluate the role of tumor stroma, including cancer associated fibroblasts (CAFs), tumor associated macrophages (TAMs), endothelial cells, adipocytes, dendritic cells and extracellular matrix (ECM) components in EOC growth and metastasis. Lastly, we discuss therapeutic approaches for targeting EOC. Unraveling the mechanisms underlying EOC metastasis will open up avenues to the design of new therapeutic options. For instance, understanding the molecular mechanisms involved in the hematogenous metastasis of EOC, the biology of CTCs, and the detailed mechanisms through which EOC cells take advantage of stromal cells may help to find new opportunities for targeting EOC metastasis.

The active fraction of Garcinia yunnanensis suppresses the progression of colorectal carcinoma by interfering with tumorassociated macrophage-associated M2 macrophage polarization in vivo and in vitro

Colorectal cancer (CRC) is the third most common solid tumor worldwide and has shown resistance to several immunotherapies, particularly immune checkpoint blockade therapy, which is effective in many other types of cancer. Our previous studies indicated that the active fraction of Garcinia yunnanensis (YTE-17), had potent anticancer activities by regulating multiple signaling pathways. However, knowledge regarding the mechanism and effect of YTE-17 in the prevention of CRC is limited. This study tested the effects of YTE-17 on colon cancer development in vivo by using two murine models: the carcigenic azoxymethane/dextran sulfate sodium (AOM/DSS)-induced CRC model and a genetically induced model using Apc^Min/+ mice. Here, the tumor load, tumor number, histology, and even some oncogenes were used to evaluate the effect of YTE-17. The intragastric administration of YTE-17 for 12 weeks significantly decreased CRC incidence, tumor number and size, immunity, and some tumor-associated macrophage (TAM) markers, including CD206, Arg-1, IL-10, and TGF-β. Importantly, the macrophages depletion by clodronate (CEL) also played a role in reducing the tumor burden and inhibiting tumor development, which were not affected by YTE-17 in the Apc^Min/+ mice. Moreover, the YTE-17 treatment attenuated CRC cell growth in a co-culture system in the presence of macrophages. Consistently, YTE-17 effectively reduced the tumor burden and macrophage infiltration and enhanced immunity in the AOM/DSS and Apc^Min/+ colon tumor models. Altogether, we demonstrate that macrophages in the microenvironment may contribute to the development and progression of CRC cells and propose YTE-17 as a new potential drug option for the treatment of CRC.

Nogo-B fosters HCC progression by enhancing Yap/Taz-mediated tumor-associated macrophages M2 polarization

Tumor-associated macrophages (TAMs) and their M2-type extremely promote tumor angiogenesis, invasion and metastasis, including hepatocellular carcinoma (HCC). Nogo-B is expressed in most tissues and participates in macrophage polarization. However, whether Nogo-B is involved in the polarization and the effects of TAMs has been unclear. The expression of Nogo-B in TAMs of HCC patients is significantly increased, which correlated with the poor prognosis of the patients with HCC. Coincidentally, HCC conditioned medium (HCM) facilitated Nogo-B expression and the M2 phenotype of macrophages. Nogo-B knockdown Nogo-B significantly suppressed the M2-type polarization of macrophages and inhibited HCC cells proliferation both in vivo and in vitro. Furthermore, interference of Nogo-B facilitates macrophage-mediated apoptosis of tumor cells. Nogo-B meaningfully enhanced IL4-stimulated the alternative activation of macrophages as well as expression of the transcriptional regulators Yes-associated protein (Yap)/transcriptional coactivator with PDZ-binding motif (Taz). An inhibitor of Yap, Verteporfin, could block Nogo-B-Yap/Taz-mediated macrophages M2 polarization. Nogo-B expression in macrophages facilitates tumor-associated macrophages M2 polarization and protumoral effects of TAMs in HCC. Targeting Nogo-B/Yap/Taz in macrophages could provide a new therapeutic strategy in HCC therapy.

Ceramide and palmitic acid inhibit macrophage-mediated epithelial-mesenchymal transition in colorectal cancer

Accumulating evidence indicates that ceramide (Cer) and palmitic acid (PA) possess the ability to modulate switching of macrophage phenotypes and possess anti-tumorigenic effects; however, the underlying molecular mechanisms are largely unknown. The aim of the present study was to investigate whether Cer and PA could induce switching of macrophage polarization from the tumorigenic M2- towards the pro-inflammatory M1-phenotype, and whether this consequently altered the potential of colorectal cancer cells to undergo epithelial–mesenchymal transition (EMT), a hallmark of tumor progression. Our study showed that Cer- and PA-treated macrophages increased expression of the macrophage 1 (M1)-marker CD68 and secretion of IL-12 and attenuated expression of the macrophage 2 (M2)-marker CD163 and IL-10 secretion. Moreover, Cer and PA abolished M2 macrophage-induced EMT and migration of colorectal cancer cells. At the molecular level, this coincided with inhibition of SNAI1 and vimentin expression and upregulation of E-cadherin. Furthermore, Cer and PA attenuated expression levels of IL-10 in colorectal cancer cells co-cultured with M2 macrophages and downregulated STAT3 and NF-κB expression. For the first time, our findings suggest the presence of an IL-10-STAT3-NF-κB signaling axis in colorectal cancer cells co-cultured with M2 macrophages, mimicking the tumor microenvironment. Importantly, PA and Cer were powerful inhibitors of this signaling axis and, consequently, EMT of colorectal cancer cells. These results contribute to our understanding of the immunological mechanisms that underlie the anti-tumorigenic effects of lipids for future combination with drugs in the therapy of colorectal carcinoma.

XIAOPI formula inhibits the pre-metastatic niche formation in breast cancer via suppressing TAMs/CXCL1 signaling

Background

Recent findings suggested that premetastatic niche (PMN) is a prerequisite in mediating cancer metastasis. Previously we demonstrated that XIAOPI formula could inhibit breast cancer lung metastasis via inhibiting tumor associated macrophages (TAMs)-secreted CXCL1. Herein, we aimed to explore the effects of XIAOPI formula on preventing breast cancer PMN formation and its underlying molecular mechanisms.

Methods

CXCL1 expression of TAMs was detected by qPCR and Western blotting assay. The influences of XIAOPI formula on the proliferation of TAMs and 4 T1 in the co-culture system were tested by CCK8 or EdU staining. Transwell experiment was applied to determine the effects of XIAOPI formula on the invasion ability of HSPCs and 4 T1. Breast cancer xenografts were built by inoculating 4 T1 cells into the mammary pads of Balb/c mice and lung metastasis was monitored by luciferase imaging. Immune fluorescence assay was used to test the epithelial-mesenchymal transition process and PMN formation in the lung tissues. The effects of XIAOPI formula on TAMs phenotype, hematopoietic stem/progenitor cells (HSPCs) and myeloid-derived suppressor cells (MDSCs) were determined by flow cytometry.

Results

It was found that XIAOPI formula could inhibit the proliferation and polarization of M2 phenotype macrophages, and reduce CXCL1 expression in a dose-dependent manner. However, M1 phenotype macrophages were not significantly affected by XIAOPI formula. TAMs/CXCL1 signaling was subsequently found to stimulate the recruitment of c-Kit⁺/Sca-1⁺ HSPCs and their differentiation into CD11b⁺/Gr-1⁺ MDSCs, which were symbolic events accounting for PMN formation. Moreover, XIAOPI formula was effective in inhibiting HSPCs activation and suppressing the proliferation and metastasis of breast cancer cells 4 T1 induced by HSPCs and TAMs co-culture system, implying that XIAOPI was effective in preventing PMN formation in vitro. Breast cancer xenograft experiments further demonstrated that XIAOPI formula could inhibit breast cancer PMN formation and subsequent lung metastasis in vivo. The populations of HSPCs in the bone marrow and MDSCs in the lung tissues were all remarkably declined by XIAOPI formula treatment. However, the inhibitory effects of XIAOPI formula could be relieved by CXCL1 overexpression in the TAMs.

Conclusions

Taken together, our study provided preclinical evidence supporting the application of XIAOPI formula in preventing breast cancer PMN formation, and highlighted TAMs/CXCL1 as a potential therapeutic strategy for PMN targeting therapy.

High Dimensional Mass Cytometry Analysis Reveals Characteristics of the Immunosuppressive Microenvironment in Diffuse Astrocytomas

The tumor immune microenvironment (TIME) plays a pivotal role in tumor development, progression, and prognosis. However, the characteristics of the TIME in diffuse astrocytoma (DA) are still unclear. Leveraging mass cytometry with a panel of 33 markers, we analyzed the infiltrating immune cells from 10 DA and 4 oligodendroglioma (OG) tissues and provided a single cell-resolution landscape of the intricate immune microenvironment. Our study profiled the composition of the TIME in DA and confirmed the presence of immune cells, such as glioma-associated microglia/macrophages (GAMs), CD8+ T cells, CD4+ T cells, regulatory T cells (Tregs), and natural killer cells. Increased percentages of PD-1+ CD8+ T cells, TIM-3+ CD4+ T cell subpopulations, Tregs and pro-tumor phenotype GAMs substantially contribute to the local immunosuppressive microenvironment in DA. DAs and OGs share similar compositions in terms of immune cells, while GAMs in DA exhibit more inhibitory characteristics than those in OG.

Cytokines as potential combination agents with PD-1/PD-L1 blockade for cancer treatment

Immunotherapy has caused a paradigm shift in the treatment of several malignancies, particularly the blockade of programmed death-1 (PD-1) and its specific receptor/ligand PD-L1 that have revolutionized the treatment of a variety of malignancies, but significant durable responses only occur in a small percentage of patients, and other patients failed to respond to the treatment. Even those who initially respond can ultimately relapse despite maintenance treatment, there is considerable potential for synergistic combinations of immunotherapy and chemotherapy agents with immune checkpoint inhibitors into conventional cancer treatments. The clinical experience in the use of cytokines in the clinical setting indicated the efficiency of cytokine therapy in cancer immunotherapy. Combinational approaches to enhancing PD-L1/PD-1 pathways blockade efficacy with several cytokines such as interleukin (IL)-2, IL-15, IL-21, IL-12, IL-10, and interferon-α (IFN-α) may result in additional benefits. In this review, the current state of knowledge about PD-1/PD-L1 inhibitors, the date in the literature to ascertain the combination of anti-PD-1/PD-L1 antibodies with cytokines is discussed. Finally, it is noteworthy that novel therapeutic approaches based on the efficient combination of recombinant cytokines with the PD-L1/PD-1 blockade therapy can enhance antitumor immune responses against various malignancies.

The dual role of tumor necrosis factor-alpha (TNF-α) in breast cancer: molecular insights and therapeutic approaches

BACKGROUND

Breast cancer is the most prevalent cancer among women worldwide and the fifth cause of death among all cancer patients. Breast cancer development is driven by genetic and epigenetic alterations, with the tumor microenvironment (TME) playing an essential role in disease progression and evolution through mechanisms like inflammation promotion. TNF-α is one of the essential pro-inflammatory cytokines found in the TME of breast cancer patients, being secreted both by stromal cells, mainly by tumor-associated macrophages, and by the cancer cells themselves. In this review, we explore the biological and clinical impact of TNF-α in all stages of breast cancer development. First of all, we explore the correlation between TNF-α expression levels at the tumor site or in plasma/serum of breast cancer patients and their respective clinical status and outcome. Secondly, we emphasize the role of TNF-α signaling in both estrogen-positive and -negative breast cancer cells. Thirdly, we underline TNF-α involvement in epithelial-to-mesenchymal transition (EMT) and metastasis of breast cancer cells, and we point out the contribution of TNF-α to the development of acquired drug resistance.

CONCLUSIONS

Collectively, these data reveal a pro-tumorigenic role of TNF-α during breast cancer progression and metastasis. We systemize the knowledge regarding TNF-α-related therapies in breast cancer, and we explain how TNF-α may act as both a target and a drug in different breast cancer therapeutic approaches. By corroborating the known molecular effects of TNF-α signaling in breast cancer cells with the results from several preclinical and clinical trials, including TNF-α-related clinical observations, we conclude that the potential of TNF-α in breast cancer therapy promises to be of great interest.

Mechanism of lung adenocarcinoma spine metastasis induced by CXCL17

PURPOSE

Spine metastases are common in patients with lung adenocarcinoma (LUAD). Improving the clinical outcome of spine metastasis LUAD patients requires knowledge on the mechanism underlying the metastatic process. Here, we sought to decipher the effect and mechanism of C-X-C motif chemokine ligand 17 (CXCL17) on LUAD spine metastasis.

METHODS

Clinical tumor tissue samples, lung cancer cell lines and a TCGA dataset were used for CXCL17 expression analyses. A transwell invasion assay was used to assess the chemotaxis capacity of mononuclear macrophages induced by CXCL17. Western blotting was performed to explore the mechanism of mononuclear macrophage chemotaxis towards CXCL17. A cell counting kit-8 assay was employed to investigate the effect of conditioned medium from M1 and M2 macrophages on the proliferation of lung cancer cells.

RESULTS

We found that the expression of CXCL17 was higher in clinical LUAD samples and LUAD cell lines than in lung squamous cell carcinoma (LUSC) samples and cell lines. Moreover, we found that CXCL17 increased the migration of THP-1 mononuclear macrophages by activating the Src/FAK pathway. In addition, we found that conditioned medium from M2 macrophages promoted the proliferation of LUAD cells.

CONCLUSIONS

From our data we conclude that CXCL17 is a key regulator of LUAD spine metastasis. CXCL17 and its downstream Src/FAK pathway may serve as clinical intervention targets.

Clinicopathologic and prognostic significance of tumor-associated macrophages in patients with hepatocellular carcinoma: A meta-analysis

PURPOSE

Tumor-associated macrophages (TAMs) deserve more focus because of its clinicopathologic and prognostic roles in solid tumors. However, the prognostic value of TAMs in patients with hepatocellular carcinoma (HCC) is still controversial. We performed a meta-analysis to resolve the issue.

METHODS

We selected relevant studies from the Cochrane Library, Embase and PubMed databases. The hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated employing fixed-effect or random-effect models depending on the heterogeneity of the included trials. Moreover, we also performed subgroup analysis, cumulative meta-analysis, sensitivity analysis, and bias analysis (Egger's test).

RESULTS

A total of 20 observational studies with 4297 patients were enrolled. For TAMs subsets, high density of CD68+ TAMs in either intratumor (IT) (pooled HR = 1.417; 95% CI = 1.092-1.839; P = 0.009) or peritumor (PT) (pooled HR = 1.393; 95% CI = 1.022-1.899; P = 0.036) was associated with a poor OS. High density of CD68+ TAMs in IT was also associated with high AFP value, large tumor size, absent encapsulation, present vascular invasion, and later tumor-nodes-metastasis (TNM) stage. High density of CD163+ macrophages in serum was associated with a poor OS (pooled HR = 5.698; 95% CI = 3.062-10.603; P < 0.001). High density of CD204+ TAMs in IT was associated with a poor OS (pooled HR = 1.947; 95% CI = 1.387-2.733; P < 0.001. High density of CD206+ TAMs in IT was associated with a poor OS (pooled HR = 1.723; 95% CI = 1.308-2.270; P < 0.001) and DFS (pooled HR = 1.711; 95% CI = 1.214-2.412; P = 0.002). However, high density of CD169+ TAMs in IT was associated with a good OS (pooled HR = 0.471; 95% CI = 0.343-0.647; P = 0.037).

CONCLUSIONS

TAMs could serve as independent predictive indicators and therapeutic targets for HCC. Further trials are needed to elucidate the exact relationship and the underlying mechanism.

The yin and yang of imaging tumor associated macrophages with PET and MRI

Tumor associated macrophages (TAM) are key players in the cancer microenvironment. Molecular imaging modalities such as MRI and PET can be used to track and monitor TAM dynamics in tumors non-invasively, based on specific uptake and quantification of MRI-detectable nanoparticles or PET-detectable radiotracers. Particular molecular signatures can be leveraged to target anti-inflammatory TAM, which support tumor growth, and pro-inflammatory TAM, which suppress tumor growth. In addition, TAM-directed imaging probes can be designed to include immune modulating properties, thereby leading to combined diagnostic and therapeutic (theranostic) effects. In this review, we will discuss the complementary role of TAM-directed radiotracers and iron oxide nanoparticles for monitoring cancer immunotherapies with PET and MRI technologies. In addition, we will outline how TAM-directed imaging and therapy is interdependent and can be connected towards improved clinical outcomes

Current perspectives on the immunosuppressive tumor microenvironment in hepatocellular carcinoma: challenges and opportunities

Incidence of hepatocellular carcinoma (HCC) is on the rise due to the prevalence of chronic hepatitis and cirrhosis. Although there are surgical and chemotherapy treatment avenues the mortality rate of HCC remains high. Immunotherapy is currently the new frontier of cancer treatment and the immunobiology of HCC is emerging as an area for further exploration. The tumor microenvironment coexists and interacts with various immune cells to sustain the growth of HCC. Thus, immunosuppressive cells play an important role in the anti-tumor immune response. This review will discuss the current concepts of immunosuppressive cells, including tumor-associated macrophages, marrow-derived suppressor cells, tumor-associated neutrophils, cancer-associated fibroblasts, and regulatory T cell interactions to actively promote tumorigenesis. It further elaborates on current treatment modalities and future areas of exploration.