MiR-98 modulates macrophage polarization and suppresses the effects of tumor-associated macrophages on promoting invasion and epithelial-mesenchymal transition of hepatocellular carcinoma

The multifaceted roles of macrophages in the transition from hepatitis to hepatocellular carcinoma: From mechanisms to therapeutic strategies

Macrophages are central to the progression from hepatitis to hepatocellular carcinoma (HCC), with their remarkable plasticity and ability to adapt to the changing liver microenvironment. Chronic inflammation, fibrosis, and ultimately tumorigenesis are driven by macrophage activation, making them key regulators of liver disease progression. This review explores the diverse roles of macrophages in the transition from hepatitis to HCC. In the early stages of hepatitis, macrophages are essential for pathogen clearance and tissue repair. However, chronic activation leads to prolonged inflammation, which exacerbates liver damage and promotes fibrosis. As the disease progresses to liver fibrosis, macrophages interact with hepatic stellate cells, fostering a pro-tumorigenic microenvironment that supports HCC development. In hepatocarcinogenesis, macrophages contribute to tumor initiation, growth, metastasis, immune evasion, cancer stem cell maintenance, and angiogenesis. Their functional plasticity enables them to adapt to the tumor microenvironment, thereby promoting tumor progression and resistance to therapy. Targeting macrophages represents a promising strategy for preventing and treating HCC. Therapeutic approaches, including reprogramming macrophage phenotypes to enhance anti-tumor immunity, blocking macrophage recruitment and activation, and utilizing nanoparticle-based drug delivery systems, may provide new avenues for combating HCC by modulating macrophage functions and tumor microenvironment dynamics.

Macrophage-derived cathepsin L promotes epithelial-mesenchymal transition and M2 polarization in gastric cancer

BACKGROUND

Advanced gastric tumors are extremely prone to metastasize the in 20%-30% of gastric cancer, and patients have a poor prognosis despite systemic chemotherapy. Peritoneal metastases from gastric cancer usually indicate the end stage of the disease without curative treatment.

AIM

To peritoneal metastasis for facilitating clinical therapy are urgently needed.

METHODS

Immunohistochemical staining and immunofluorescence staining were used to demonstrate the high expression of cathepsin L (CTSL) in human gastric cancer tissues and its localization in cells. Lentivirus transfection was used to construct stable cell lines. Transwell invasion assays, wound healing assays, and animal tests were used to determine the relationships between CTSL and epithelial-mesenchymal transition (EMT) and tumorigenic potential in vivo.

RESULTS

We observed that macrophage-derived CTSL promoted gastric cancer cell migration and metastasis via the EMT pathway in vitro and in vivo, which involved macrophage polarization. Our findings suggest that macrophages improve extracellular matrix remodeling and hence facilitate tumor metastasis. Ablation of CTSL in macrophages within the tumor microenvironment may improve tumor therapy and the prognosis of patients with gastric cancer peritoneal metastasis.

CONCLUSION

In consideration of our findings, tumor-associated macrophage-derived CTSL is an important factor that promotes the metastasis and invasion of gastric cancer cells, and the targeting of CTSL may potentially improve the prognosis of patients with gastric cancer with peritoneal metastasis.

Tumor-associated macrophages and CD8+ T cells: dual players in the pathogenesis of HBV-related HCC

HBV infection is a key risk factor for the development and progression of hepatocellular carcinoma (HCC), a highly invasive tumor, and is characterized by its persistent immunosuppressive microenvironment. This review provides an in-depth analysis of HBV-related HCC and explores the interactions between neutrophils, natural killer cells, and dendritic cells, examining their roles in regulating tumor-associated macrophages and CD8+ T cells and shaping the tumor microenvironment. Two critical players in the immunosuppressive milieu of HBV-related HCC are CD8+ T cells and tumor-associated macrophages (TAMs). The study explores how TAMs, initially recruited to combat infection, transform, adopting a tumor-promoting phenotype, turning against the body, promoting tumor cell proliferation, suppressing anti-tumor immunity, and assisting in the spread of cancer. Meanwhile, CD8+ T cells, crucial for controlling HBV infection, become dysfunctional and exhausted in response to persistent chronic viral inflammation. The review then dissects how TAMs manipulate this immune response, further depleting CD8+ T cell functions through mechanisms like arginine deprivation and creating hypoxic environments that lead to exhaustion. Finally, it explores the challenges and promising therapeutic avenues that target TAMs and CD8+ T cells, either separately or in combination with antiviral therapy and personalized medicine approaches, offering hope for improved outcomes in HBV-related HCC.

Epigenetic tuning of tumour-associated macrophages (TAMs): a potential approach in hepatocellular carcinoma (HCC) immunotherapy

Recent development in immunotherapy for cancer treatment has substantiated to be more effective than most of the other treatments. Immunity is the first line of defence of the body; nevertheless, cancerous cells can manipulate immunity compartments to play several roles in tumour progression. Tumour-associated macrophages (TAMs), one of the most dominant components in the tumour microenvironment, are recognized as anti-tumour suppressors. Unfortunately, the complete behaviour of TAMs is still unclear and understudied. TAM density is directly correlated with the progression and poor prognosis of hepatocellular carcinoma (HCC), therefore studying TAMs from different points of view passing by all the factors that may affect its existence, polarization, functions and repolarization are of great importance. Different epigenetic regulations were reported to have a direct relation with both HCC and TAMs. Here, this review discusses different epigenetic regulations that can affect TAMs in HCC whether positively or negatively.

Biological impact and therapeutic implication of tumor-associated macrophages in hepatocellular carcinoma

The tumor microenvironment is a complex space comprised of normal, cancer and immune cells. The macrophages are considered as the most abundant immune cells in tumor microenvironment and their function in tumorigenesis is interesting. Macrophages can be present as M1 and M2 polarization that show anti-cancer and oncogenic activities, respectively. Tumor-associated macrophages (TAMs) mainly have M2 polarization and they increase tumorigenesis due to secretion of factors, cytokines and affecting molecular pathways. Hepatocellular carcinoma (HCC) is among predominant tumors of liver that in spite of understanding its pathogenesis, the role of tumor microenvironment in its progression still requires more attention. The presence of TAMs in HCC causes an increase in growth and invasion of HCC cells and one of the reasons is induction of glycolysis that such metabolic reprogramming makes HCC distinct from normal cells and promotes its malignancy. Since M2 polarization of TAMs stimulates tumorigenesis in HCC, molecular networks regulating M2 to M1 conversion have been highlighted and moreover, drugs and compounds with the ability of targeting TAMs and suppressing their M2 phenotypes or at least their tumorigenesis activity have been utilized. TAMs increase aggressive behavior and biological functions of HCC cells that can result in development of therapy resistance. Macrophages can provide cell-cell communication in HCC by secreting exosomes having various types of biomolecules that transfer among cells and change their activity. Finally, non-coding RNA transcripts can mainly affect polarization of TAMs in HCC.

MicroRNA-98: the multifaceted regulator in human cancer progression and therapy

MicroRNA-98 (miR-98) stands as an important molecule in the intricate landscape of oncology. As a subset of microRNAs, these small non-coding RNAs have accompanied a new era in cancer research, underpinning their significant roles in tumorigenesis, metastasis, and therapeutic interventions. This review provides a comprehensive insight into the biogenesis, molecular properties, and physiological undertakings of miR-98, highlighting its double-edged role in cancer progression-acting both as a tumor promoter and suppressor. Intriguingly, miR-98 has profound implications for various aspects of cancer progression, modulating key cellular functions, including proliferation, apoptosis, and the cell cycle. Given its expression patterns, the potential of miR-98 as a diagnostic and prognostic biomarker, especially in liquid biopsies and tumor tissues, is explored, emphasizing the hurdles in translating these findings clinically. The review concludes by evaluating therapeutic avenues to modulate miR-98 expression, addressing the challenges in therapy resistance, and assessing the efficacy of miR-98 interventions. In conclusion, while miR-98's involvement in cancer showcases promising diagnostic and therapeutic avenues, future research should pivot towards understanding its role in tumor-stroma interactions, immune modulation, and metabolic regulation, thereby unlocking novel strategies for cancer management.

Macrophages Orchestrate the Liver Tumor Microenvironment

Liver cancer is one of the leading causes of cancer-related mortality. Hepatocellular carcinoma and cholangiocarcinoma are the most common types, and despite numerous advances, therapeutic options still remain poor for these cancer patients. Tumor development and progression strictly depend on a supportive tumor microenvironment (TME). Tumor-associated macrophages (TAMs) are the most abundant immune cells population within a tumorigenic liver; they sustain cancer cells' growth and invasiveness, and their presence is correlated with a poor prognosis. Furthermore, TAM cross-talk with cells and components of the TME promotes immunosuppression, a desmoplastic response, and angiogenesis. In this review, we summarize the latest advances in understanding TAM heterogeneity and function, with a particular focus on TAM modulation of the TME. We also discuss the potential of targeting macrophage subpopulations and how this is now being exploited in current clinical trials for the treatment of liver cancer.

Epigenetic regulation of hepatocellular carcinoma progression: MicroRNAs as therapeutic, diagnostic and prognostic factors

Hepatocellular carcinoma (HCC), a significant challenge for public healthcare systems in developed Western countries including the USA, Canada, and the UK, is influenced by different risk factors including hepatitis virus infections, alcoholism, and smoking. The disruption in the balance of microRNAs (miRNAs) plays a vital function in tumorigenesis, given their function as regulators in numerous signaling networks. These miRNAs, which are mature and active in the cytoplasm, work by reducing the expression of target genes through their impact on mRNAs. MiRNAs are particularly significant in HCC as they regulate key aspects of the tumor, like proliferation and invasion. Additionally, during treatment phases such as chemotherapy and radiotherapy, the levels of miRNAs are key determinants. Pre-clinical experiments have demonstrated that altered miRNA expression contributes to HCC development, metastasis, drug resistance, and radio-resistance, highlighting related molecular pathways and processes like MMPs, EMT, apoptosis, and autophagy. Furthermore, the regulatory role of miRNAs in HCC extends beyond their immediate function, as they are also influenced by other epigenetic factors like lncRNAs and circular RNAs (circRNAs), as discussed in recent reviews. Applying these discoveries in predicting the prognosis of HCC could mark a significant advancement in the therapy of this disease.

MicroRNAs Associated with a Bad Prognosis in Acute Myeloid Leukemia and Their Impact on Macrophage Polarization

MicroRNAs (miRNAs) are short, non-coding ribonucleic acids (RNAs) associated with gene expression regulation. Since the discovery of the first miRNA in 1993, thousands of miRNAs have been studied and they have been associated not only with physiological processes, but also with various diseases such as cancer and inflammatory conditions. MiRNAs have proven to be not only significant biomarkers but also an interesting therapeutic target in various diseases, including cancer. In acute myeloid leukemia (AML), miRNAs have been regarded as a welcome addition to the limited therapeutic armamentarium, and there is a vast amount of data on miRNAs and their dysregulation. Macrophages are innate immune cells, present in various tissues involved in both tissue repair and phagocytosis. Based on their polarization, macrophages can be classified into two groups: M1 macrophages with pro-inflammatory functions and M2 macrophages with an anti-inflammatory action. In cancer, M2 macrophages are associated with tumor evasion, metastasis, and a poor outcome. Several miRNAs have been associated with a poor prognosis in AML and with either the M1 or M2 macrophage phenotype. In the present paper, we review miRNAs with a reported negative prognostic significance in cancer with a focus on AML and analyze their potential impact on macrophage polarization.

The role of tumor-associated macrophages in hepatocellular carcinoma progression: A narrative review

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in the world, with complex etiology and mechanism, and a high mortality rate. Tumor-associated macrophages (TAMs) are an important part of the HCC tumor microenvironment. Studies in recent years have shown that TAMs are involved in multiple stages of HCC and are related to treatment and prognosis in HCC. The specific mechanisms between TAMs and HCC are gradually being revealed. This paper reviews recent advances in the mechanisms associated with TAMs in HCC, concentrating on an overview of effects of TAMs on drug resistance in HCC and the signaling pathways linked with HCC, providing clues for the treatment and prognosis determination of HCC.

Mechanisms of tumor-associated macrophages affecting the progression of hepatocellular carcinoma

Tumor-associated macrophages (TAMs) are essential components of the immune cell stroma of hepatocellular carcinoma. TAMs originate from monocytic myeloid-derived suppressor cells, peripheral blood monocytes, and kupffer cells. The recruitment of monocytes to the HCC tumor microenvironment is facilitated by various factors, leading to their differentiation into TAMs with unique phenotypes. TAMs can directly activate or inhibit the nuclear factor-κB, interleukin-6/signal transducer and signal transducer and activator of transcription 3, Wnt/β-catenin, transforming growth factor-β1/bone morphogenetic protein, and extracellular signal-regulated kinase 1/2 signaling pathways in tumor cells and interact with other immune cells via producing cytokines and extracellular vesicles, thus affecting carcinoma cell proliferation, invasive and migratory, angiogenesis, liver fibrosis progression, and other processes to participate in different stages of tumor progression. In recent years, TAMs have received much attention as a prospective treatment target for HCC. This review describes the origin and characteristics of TAMs and their mechanism of action in the occurrence and development of HCC to offer a theoretical foundation for further clinical research of TAMs.

The mononuclear phagocyte system in hepatocellular carcinoma

The mononuclear phagocyte system (MPS) consists of monocytes, dendritic cells and macrophages, which play vital roles in innate immune defense against cancer. Hepatocellular carcinoma (HCC) is a complex disease that is affected or initiated by many factors, including chronic hepatitis B virus infection, hepatitis C virus infection, metabolic disorders or alcohol consumption. Liver function, tumor stage and the performance status of patients affect HCC clinical outcomes. Studies have shown that targeted treatment of tumor microenvironment disorders may improve the efficacy of HCC treatments. Cytokines derived from the innate immune response can regulate T-cell differentiation, thereby shaping adaptive immunity, which is associated with the prognosis of HCC. Therefore, it is important to elucidate the function of the MPS in the progression of HCC. In this review, we outline the impact of HCC on the MPS. We illustrate how HCC reshapes MPS cell phenotype remodeling and the production of associated cytokines and characterize the function and impairment of the MPS in HCC.

Exosomal miR-628-5p from M1 polarized macrophages hinders m6A modification of circFUT8 to suppress hepatocellular carcinoma progression

BACKGROUND

Hepatocellular carcinoma (HCC) is the most common type of liver cancer. CircFUT8 has been shown to be upregulated in cancers, but its function in HCC remains unclear. Tumor-associated macrophages (TAMs) are one of the main components of the tumor microenvironment (TME), and M1 macrophages function as tumor suppressors in cancers. Exosomes exert an important role in the TME, and circRNAs can be modified by m6A. We investigated the function of circFUT8 in HCC and its interaction with exosomes, M1 macrophages, and m6A.

METHODS

CircFUT8 expression was detected in HCC cells, and its effects on HCC cell growth were verified through functional assays. Mechanism assays including RNA pull down, RNA-binding protein immunoprecipitation (RIP), and luciferase reporter assays were undertaken to verify how circFUT8 may interact with miR-628-5p, and how these molecules may modulate HCC cell malignancy via interacting with exosomes and macrophages.

RESULTS

CircFUT8 was upregulated in HCC cells and it accelerated HCC cell growth. Exosomes derived from M1 macrophages transferred miR-628-5p to HCC cells to inhibit human methyltransferase-like 14 (METTL14) expression. METTL14 promoted circFUT8 m6A modification and facilitated its nuclear export to the cytoplasm, where M1 macrophages regulated the circFUT8/miR-552-3p/CHMP4B pathway, thereby suppressing HCC progression.

CONCLUSION

M1 macrophages-derived exosomal miR-628-5p inhibited the m6A modification of circFUT8, inhibiting HCC development.

Tumor-associated macrophages in liver cancer: From mechanisms to therapy

Multidimensional analyses have demonstrated the presence of a unique tumor microenvironment (TME) in liver cancer. Tumor-associated macrophages (TAMs) are among the most abundant immune cells infiltrating the TME and are present at all stages of liver cancer progression, and targeting TAMs has become one of the most favored immunotherapy strategies. In addition, macrophages and liver cancer cells have distinct origins. At the early stage of liver cancer, macrophages can provide a niche for the maintenance of liver cancer stem cells. In contrast, cancer stem cells (CSCs) or poorly differentiated tumor cells are key factors modulating macrophage activation. In the present review, we first propose the origin connection between precursor macrophages and liver cancer cells. Macrophages undergo dynamic phenotypic transition during carcinogenesis. In this course of such transition, it is critical to determine the appropriate timing for therapy and block specific markers to suppress pro-tumoral TAMs. The present review provides a more detailed discussion of transition trends of such surface markers than previous reviews. Complex crosstalk occurs between TAMs and liver cancer cells. TAMs play indispensable roles in tumor progression, angiogenesis, and autophagy due to their heterogeneity and robust plasticity. In addition, macrophages in the TME interact with other immune cells by directing cell-to-cell contact or secreting various effector molecules. Similarly, tumor cells combined with other immune cells can drive macrophage recruitment and polarization. Despite the latest achievements and the advancements in treatment strategies following TAMs studies, comprehensive discussions on the communication between macrophages and cancer cells or immune cells in liver cancer are currently lacking. In this review, we discussed the interactions between TAMs and liver cancer cells (from cell origin to maturation), the latest therapeutic strategies (including chimeric antigen receptor macrophages), and critical clinical trials for hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA) to provide a rationale for further clinical investigation of TAMs as a potential target for treating patients with liver cancer.

Overexpression of Pigment epithelium-derived factor in breast cancer cell-derived exosomes induces M1 polarization in macrophages

M2 macrophages, the major component of tumor microenvironment, are recognized as important player in tumor progression. M2 macrophages mediate this effect by promoting tumor angiogenesis, tumor metastasis, and suppression of tumor immunity. Reprogramming of M2 macrophages can serve as a promising strategy in cancer immunotherapy. In this study, we constructed pigment epithelium-derived factor (PEDF) expressing vector and transfected MDA-MB-231 cells with this construct. Then, exosomes were isolated from transfected cells and M2 macrophages were incubated with isolated exosomes from transfected cell. The effect of isolated exosomes on macrophage polarization was examined by real-time PCR and ELISA. The results demonstrated reprogramming of M2 macrophages after incubation with isolated exosomes from PEDF transfected cells. M2-to-M1 repolarization of macrophages was confirmed by upregulation of CD80, IRF5, MCP1, and IL-1β and repression of CD206, Arg, TGM2, and TGF-β. Therefore, these findings revealed that introducing PEDF into exosomes by genetic manipulation of parent cells may be a potential approach for reprogramming of M2 macrophages in cancer.

Twist1 regulates macrophage plasticity to promote renal fibrosis through galectin-3

Renal interstitial fibrosis is the pathological basis of end-stage renal disease, in which the heterogeneity of macrophages in renal microenvironment plays an important role. However, the molecular mechanisms of macrophage plasticity during renal fibrosis progression remain unclear. In this study, we found for the first time that increased expression of Twist1 in macrophages was significantly associated with the severity of renal fibrosis in IgA nephropathy patients and mice with unilateral ureteral obstruction (UUO). Ablation of Twist1 in macrophages markedly alleviated renal tubular injury and renal fibrosis in UUO mice, accompanied by a lower extent of macrophage infiltration and M2 polarization in the kidney. The knockdown of Twist1 inhibited the chemotaxis and migration of macrophages, at least partially, through the CCL2/CCR2 axis. Twist1 downregulation inhibited M2 macrophage polarization and reduced the secretion of the profibrotic factors Arg-1, MR (CD206), IL-10, and TGF-β. Galectin-3 was decreased in the macrophages of the conditional Twist1-deficient mice, and Twist1 was shown to directly activate galectin-3 transcription. Up-regulation of galectin-3 recovered Twist1-mediated M2 macrophage polarization. In conclusion, Twist1/galectin-3 signaling regulates macrophage plasticity (M2 phenotype) and promotes renal fibrosis. This study could suggest new strategies for delaying kidney fibrosis in patients with chronic kidney disease.

Macrophage Polarization and Its Role in Liver Disease

Macrophages are important immune cells in innate immunity, and have remarkable heterogeneity and polarization. Under pathological conditions, in addition to the resident macrophages, other macrophages are also recruited to the diseased tissues, and polarize to various phenotypes (mainly M1 and M2) under the stimulation of various factors in the microenvironment, thus playing different roles and functions. Liver diseases are hepatic pathological changes caused by a variety of pathogenic factors (viruses, alcohol, drugs, etc.), including acute liver injury, viral hepatitis, alcoholic liver disease, metabolic-associated fatty liver disease, liver fibrosis, and hepatocellular carcinoma. Recent studies have shown that macrophage polarization plays an important role in the initiation and development of liver diseases. However, because both macrophage polarization and the pathogenesis of liver diseases are complex, the role and mechanism of macrophage polarization in liver diseases need to be further clarified. Therefore, the origin of hepatic macrophages, and the phenotypes and mechanisms of macrophage polarization are reviewed first in this paper. It is found that macrophage polarization involves several molecular mechanisms, mainly including TLR4/NF-κB, JAK/STATs, TGF-β/Smads, PPARγ, Notch, and miRNA signaling pathways. In addition, this paper also expounds the role and mechanism of macrophage polarization in various liver diseases, which aims to provide references for further research of macrophage polarization in liver diseases, contributing to the therapeutic strategy of ameliorating liver diseases by modulating macrophage polarization.

Macrophages as key regulators of liver health and disease

Macrophages are a heterogeneous population of innate immune cells and key cellular components of the liver. Hepatic macrophages consist of embryologically-derived resident Kupffer cells (KC), recruited monocyte-derived macrophages (MDM) and capsular macrophages. Both the diversity and plasticity of hepatic macrophage subsets explain their different functions in the maintenance of hepatic homeostasis and in injury processes in acute and chronic liver diseases. In this review, we assess the evidence for macrophage involvement in regulating both liver health and injury responses in liver diseases including acute liver injury (ALI), chronic liver disease (CLD) (including liver fibrosis) and hepatocellular carcinoma (HCC). In healthy livers, KC display critical functions such as phagocytosis, danger signal recognition, cytokine release, antigen processing and the ability to orchestrate immune responses and maintain immunological tolerance. However, in most liver diseases there is a striking hepatic MDM expansion, which orchestrate both disease progression and regression. Single-cell approaches have transformed our understanding of liver macrophage heterogeneity, dynamics, and functions in both human samples and preclinical models. We will further discuss the new insights provided by these approaches and how they are enabling high-fidelity work to specifically identify pathogenic macrophage subpopulations. Given the important role of macrophages in regulating injury responses in a broad range of settings, there is now a huge interest in developing new therapeutic strategies aimed at targeting macrophages. Therefore, we also review the current approaches being used to modulate macrophage function in liver diseases and discuss the therapeutic potential of targeting macrophage subpopulations as a novel treatment strategy for patients with liver disorders.

Tumor Properties Mediate the Relationship Between Peripheral Blood Monocytes and Tumor-Associated Macrophages in Breast Cancer

In cancer patients, circulating monocytes show functional alterations. Since monocytes are precursors of tumor-associated macrophages (TAMs), TAMs ensuring tumor viability are potentially replenished through the recruitment of monocytes with specific properties. We demonstrated that locoregional metastasis and circulating factors, such as CD45-EpCAM + CD44 + CD24-/low circulating tumor cells, and serum MCP-1 and HMGB1 were statistically associated with modulation of the monocyte features in breast cancer patients. The count of circulating CD45-EpCAM + cells correlated with CD68+, CD163 + monocyte in blood, and with density of CD68 + TAM in breast cancer tumors. Overall, the relationship between monocytes and TAMs is mediated by the tumor in breast cancer patients.

Astragalus polysacharin inhibits hepatocellular carcinoma-like phenotypes in a murine HCC model through repression of M2 polarization of tumour-associated macrophages

CONTEXT

Astragalus polysaccharin (APS), an extract of Astragalus propinquus Schischk, exerts antitumor effects in hepatocellular carcinoma (HCC).

OBJECTIVE

This study investigated the mechanism of action of APS in HCC.

MATERIALS AND METHODS

Tumour-associated macrophages (TAMs) were treated with APS (0, 8, 16 mg/mL) for 24 h. APS (16 mg/mL)-treated TAMs were co-cultured with MHCC97H/Huh7 cells for 24 h. Finally, BALB/c nude mice were divided into PBS, APS (50 mg/kg), APS (100 mg/kg), APS (200 mg/kg) groups: mice were inoculated with Huh7 cells to construct tumour xenograft model, followed by administration of APS (50, 100, 200 mg/kg) or PBS daily for 30 days. Cell proliferation, migration, invasion, tumour growth, macrophage markers and proportions were measured.

RESULTS

APS 16 mg/mL treatment enhanced the expression of M1 macrophage markers (iNOS, IL-1β and TNF-α) and M1 macrophage proportions, while reducing the expression of M2 macrophage markers (IL-10, Arg-1) and M2 macrophage proportions in TAMs. Moreover, the APS-mediated M1 phenotype of TAMs significantly repressed cell proliferation, migration and invasion of MHCC97H and Huh7 cells. Moreover, APS (50, 100, 200 mg/kg) enhanced M1 macrophage proportions and reduced M2 macrophage proportions in the tumour tissues, and thus inhibited tumour growth of HCC.

DISCUSSION AND CONCLUSIONS

APS inhibits HCC-like phenotypes in a murine HCC model through repression of M2 polarization of TAMs. This work provides a novel theoretical basis for the application of APS in the clinical treatment of HCC.

M2 macrophage-derived extracellular vesicles facilitate CD8+T cell exhaustion in hepatocellular carcinoma via the miR-21-5p/YOD1/YAP/β-catenin pathway

Hepatocellular carcinoma (HCC) is a common malignancy. CD8⁺ T cell-mediated immune response is critical for the inhibition of HCC progression. M2 macrophages participate in HCC progression. This study set out to investigate the effect of M2 macrophage-derived extracellular vesicles (EVs) on CD8⁺ T cell exhaustion in HCC. M2 macrophage-derived EVs were isolated and identified. The murine model of primary HCC was established through DEN/CCl₄ induction, and model mice were injected with EVs. Peripheral blood mononuclear cells (PBMCs) were isolated from the mouse liver and CD8⁺ T cells were sorted. The expressions of immune checkpoint inhibitory receptors and effector cytokines on CD8⁺ T cells were detected, followed by the evaluation of CD8⁺ T cell proliferation and killing function. miR-21-5p expression in M2 macrophage-derived EVs was detected. The binding relationship between miR-21-5p and YOD1 was verified. The activation of the YAP/β-catenin pathway was detected. Consequently, M2 macrophage-derived EVs promoted CD8⁺ T cell exhaustion in HCC mice. miR-21-5p expression was upregulated in M2 macrophage-derived EVs, and EVs carried miR-21-5p into HCC tissues. miR-21-5p targeted YOD1. Inhibition of miR-21-5p or overexpression of YOD1 annulled the promoting effect of EVs on CD8⁺ T cell exhaustion. YOD1 inactivated the YAP/β-catenin pathway. In conclusion, M2 macrophage-derived EVs facilitated CD8⁺ T cell exhaustion via the miR-21-5p/YOD1/YAP/β-catenin axis. This study may confer novel insights into the immunotherapy of HCC.

The Epigenetic Regulation of Microenvironment in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a highly lethal and complex malignancy strongly influenced by the surrounding tumor microenvironment. The HCC microenvironment comprises hepatic stellate cells (HSCs), tumor-associated macrophages (TAMs), stromal and endothelial cells, and the underlying extracellular matrix (ECM). Emerging evidence demonstrates that epigenetic regulation plays a crucial role in altering numerous components of the HCC tumor microenvironment. In this review, we summarize the current understanding of the mechanisms of epigenetic regulation of the microenvironment in HCC. We review recent studies demonstrating how specific epigenetic mechanisms (DNA methylation, histone regulation, and non-coding RNAs mediated regulation) in HSCs, TAMs, and ECM, and how they contribute to HCC development, so as to gain new insights into the treatment of HCC via regulating epigenetic regulation in the tumor microenvironment.

Potential therapeutic targets in the tumor microenvironment of hepatocellular carcinoma: reversing the protumor effect of tumor-associated macrophages

In hepatocellular carcinoma patients, due to the microenvironmental specificity of liver, the tumor microenvironment exhibits high immunosuppression and drug resistance, resulting in excessive or insufficient responses to immunotherapy. The dynamic interactions between tumor cells and immune modulators in the TME significantly impact the occurrence and development of tumors, efficacy, and drug resistance, which can create a much more positive response to immunotherapy. Moreover, with the wide application of single-cell sequencing technology in the TME, increasing evidence shows an interaction network among cells. Sequencing results suggest that specific tumor-associated macrophages are a hub node, connecting different cell populations in the cell interaction network, and can could regulate tumor generation and antitumor immunity. This review focused on therapeutic targets that could be targeted to remodel the tumor microenvironment and reprogram the tumor-associated macrophage phenotype in hepatocellular carcinoma patients, thereby improving immunotherapeutic efficacy.

The role of tumor-associated macrophages in primary hepatocellular carcinoma and its related targeting therapy

Liver macrophages consist of ontogenically distinct populations termed Kupffer cells and monocyte-derived macrophages. Tumor-associated macrophages (TAMs) inhepatocellularcarcinoma (HCC) play a prominent role in tumormicroenvironment by presenting M1(induced by IFN γ along with LPS) and M2(induced by IL-4 and IL13) polarization. Although TAMs are involved in tumor immune surveillance during the course of HCC, they contribute to tumour progression at different levels by inhibiting the anti-tumor immune response, promoting the generation of blood vessels and lymphatic vessels, and supporting the proliferation and survival of tumor cells. In this paper, the multiple functions of TAMs in HCC were reviewed to provide assistance for future researches about therapeutic approaches.

The Role of Tumor Associated Macrophages in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide and represents a classic paradigm of inflammation-related cancer. Various inflammation-related risk factors jointly contribute to the development of chronic inflammation in the liver. Chronic inflammation, in turn, leads to continuous cycles of destruction-regeneration in the liver, contributing to HCC development and progression. Tumor associated macrophages are abundant in the tumor microenvironment of HCC, promoting chronic inflammation and HCC progression. Hence, better understanding of the mechanism by which tumor associated macrophages contribute to the pathogenesis of HCC would allow for the development of novel macrophage-targeting immunotherapies. This review summarizes the current knowledge regarding the mechanisms by which macrophages promote HCC development and progression, as well as information from ongoing therapies and clinical trials assessing the efficacy of macrophage-modulating therapies in HCC patients.

Intrahepatic cholangiocarcinoma induced M2-polarized tumor-associated macrophages facilitate tumor growth and invasiveness

BACKGROUND

M2-polarized tumor-associated macrophages (M2-TAMs) have been shown to correlate with the progression of various cancers, including intrahepatic cholangiocarcinoma (ICC). However, the interactions and mechanism between M2 macrophages and ICC are not completely clear. We aimed to clarify whether M2 macrophages promote the malignancy of ICC and its mechanism.

METHODS

Two progressive murine models of ICC were used to evaluate the alterations in different macrophage populations and phenotypes. Furthermore, we assessed M2 macrophage infiltration in 48 human ICC and 15 normal liver samples. The protumor functions and the underlying molecular mechanisms of M2 macrophages in ICC were investigated in an in vitro coculture system.

RESULTS

We found that the number of M2 macrophages was significantly higher in ICC tissues than in normal bile ducts in the two murine models. M2 macrophage infiltration was highly increased in peritumoral compared with intratumoral regions and normal liver (p < 0.01). ICC cells induced macrophages to differentiate into the M2-TAM phenotype, and coculture with these M2 macrophages promoted ICC cell proliferation, invasion and epithelial-mesenchymal transition (EMT) in vitro. Mechanistically, M2-TAM-derived IL-10 promoted the malignant properties of ICC cells through STAT3 signaling. Furthermore, blockade of IL-10/STAT3 signaling partly rescued the effects of M2 macrophages on ICC.

CONCLUSION

Our results indicated that M2-polarized macrophages induced by ICC promote tumor growth and invasiveness through IL-10/STAT3-induced EMT and might be a potential therapeutic target for ICC.

Beyond just a tight fortress: contribution of stroma to epithelial-mesenchymal transition in pancreatic cancer

Novel effective treatment is direly needed for patients with pancreatic ductal adenocarcinoma (PDAC). Therapeutics that target the driver mutations, especially the KRAS oncoprotein and its effector cascades, have been ineffective. It is increasing clear that the extensive fibro-inflammatory stroma (or desmoplasia) of PDAC plays an active role in the progression and therapeutic resistance of PDAC. The desmoplastic stroma is composed of dense extracellular matrix (ECM) deposited mainly by the cancer-associated-fibroblasts (CAFs) and infiltrated with various types of immune cells. The dense ECM functions as a physical barrier that limits tumor vasculatures and distribution of therapeutics to PDAC cells. In addition, mounting evidence have demonstrated that both CAFs and ECM promote PDAC cells aggressiveness through multiple mechanisms, particularly engagement of the epithelial-mesenchymal transition (EMT) program. Acquisition of a mesenchymal-like phenotype renders PDAC cells more invasive and resistant to therapy-induced apoptosis. Here, we critically review seminal and recent articles on the signaling mechanisms by which each stromal element promotes EMT in PDAC. We discussed the experimental models that are currently employed and best suited to study EMT in PDAC, which are instrumental in increasing the chance of successful clinical translation.

Matrix stiffness-mediated effects on macrophages polarization and their LOXL2 expression

Previously, we reported that the secreted lysyl oxidase like 2 (LOXL2) from hepatocellular carcinoma (HCC) cells under higher stiffness stimulation contributed to the formation of lung premetastatic niche. To further clarify whether matrix stiffness also alters LOXL2 expression in other cells within tumor microenvironment, we developed a gel-based culture system combined with a model of macrophage polarization to evaluate the effects of matrix stiffness on the polarization of M2 macrophages and their LOXL2 expression. THP-1 cells cultured on 6KPa, 10KPa, and 16KPa stiffness substrates were first incubated with 100nM phorbol 12-myristate 13-acetate (PMA) for 24 hours and subsequently treated with 20nM interleukin-4 (IL-4) and 20nM interleukin-13 (IL-13) for 48 hours. The polarization states of M2 macrophages under different stiffness stimulation were comparatively analyzed, and their LOXL2 expressions as well as the underlying molecular mechanism were further explored. Our results demonstrated that increased matrix stiffness remarkably strengthened M2 macrophage polarization and promoted their LOXL2 expression. Activation of integrin β5-FAK-MEK1/2-ERK1/2 pathway participated in matrix stiffness-mediated HIF-1α upregulation, and HIF-1α upregulation resulted in a significant improvement in LOXL2 expression. Additionally, M2 macrophage polarization state and LOXL2 expression in HCC tissues with COL1^High /LOX^High were consistent with the results in vitro, further confirming the regulation roles of matrix stiffness in macrophage polarization and LOXL2 expression. The findings about LOXL2 upregulation in the polarized macrophages under higher stiffness stimulation will be helpful to better understand the underlying mechanism of matrix stiffness-induced premetastatic niche formation in HCC.

Interplay between cancer cells and M2 macrophages is necessary for miR-550a-3-5p down-regulation-mediated HPV-positive OSCC progression

BACKGROUND

Human papillomavirus (HPV)-positive oral squamous cell carcinoma (OSCC) is increasing worldwide with typically higher grade and stage, while better prognosis. microRNAs (miRNAs) has been shown to play a critical role in cancer, however, their role in HPV-positive OSCC progression remains unclear.

METHODS

miRNA microarray was performed to identify differentially expressed miRNAs. qRT-PCR and FISH were performed to determine the relative expression of miR-550a-3-5p. CCK-8, Flow cytometry, Wound healing, Cell invasion assays and xenograft experiments were conducted to analyze the biological roles of miR-550a-3-5p. Tumor-associated macrophages (TAMs) generation, co-culturing of cancer cells with TAMs, Western blot, Dual-luciferase reporter gene assay, Immunohistochemistry and animal studies were performed to explore the mechanisms underlying the functions of miR-550a-3-5p.

RESULTS

We identified 19 miRNAs differentially expressed in HPV-positive OSCC specimens and miR-550a-3-5p was down-regulated. The low expression of miR-550a-3-5p correlated with higher tumor size and nodal metastasis of HPV-positive OSCC patients. Then, we found that miR-550a-3-5p suppressed the migration, invasion and EMT of HPV-positive OSCC cells dependent on decreasing M2 macrophages polarization. Moreover, miR-550a-3-5p, down-regulated by E6 oncoprotein, inhibited M2 macrophages polarization by YAP/CCL2 signaling, which in turn abrogating EMT program in HPV-positive OSCC cells. In addition, in both xenografts and clinical HPV-positive OSCC samples, miR-550a-3-5p levels were inversely associated with YAP, CCL2 expressions and the number of M2 macrophages.

CONCLUSIONS

E6/miR-550a-3-5p/YAP/CCL2 signaling induces M2 macrophages polarization to enhance EMT and progression, revealing a novel crosstalk between cancer cells and immune cells in HPV-positive OSCC microenvironment.

Interleukin-37 suppresses hepatocellular carcinoma growth through inhibiting M2 polarization of tumor-associated macrophages

Interleukin (IL)-37 has anti-tumor effects in hepatocellular carcinoma (HCC). Evidence shows that tumor-associated macrophages (TAMs) promote tumor progression. This study was designed to investigate the functional role of IL-37-mediated polarization of TAMs in HCC progression. HCC patient-derived TAMs were transfected with lentiviruses expressing IL-37 (LV-IL-37) and IL-37 siRNA and then the conditioned medium from TAMs were used to culture HCC cells (HepG2 and Huh-7). The phenotype of the macrophages was evaluated by detecting M1- or M2- type specific markers and cytokines. Cell proliferation, migration, and invasion were assessed. A tumor xenograft mouse model was generated with a subcutaneous injection of a mixture of HepG2 cells and TAMs/LV-IL-37. HCC patient-derived PBMCs showed M2 polarization and decreased IL-37 expression. Furthermore, IL-37 promoted TAMs polarization from M2 to M1 subtype through inhibiting the IL-6/STAT3 signaling. Moreover, IL-6 upregulation by recombinant human IL-6 (rhIL-6) blocked the IL-37 overexpression-mediated inhibition of HCC cell proliferation, migration, and invasion. In addition, IL-37 overexpression in HCC patient-derived TAMs inhibited tumor growth in vivo. Collectively, IL-37 suppresses HCC growth through inhibiting M2 polarization of TAMs via regulating the IL-6/STAT3 pathway.

Macrophages and hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is among the most prevalent and lethal cancers in the human population. HCC is an inflammation-associated cancer caused by different etiological factors. The chronic inflammation leads to continuous cycles of hepatocytes destructive-regenerative process and contributes to HCC initiation and progression. Macrophages play a crucial role in chronic liver inflammation. The tumor microenvironment plays a key role in the progression of HCC. Tumor-associated macrophages are a well-known component of the tumor microenvironment and abundantly infiltrate HCC microenvironment. The roles of macrophages in the development and progression of HCC have been recognized. The deep understanding of macrophages in HCC will be critical for developing effective HCC therapy. Targeting of macrophages might provide novel therapeutic approaches for HCC patients and is an emerging field of interest. This review summarizes the knowledge on the contribution of macrophages in the development and progression of HCC, as well as potential immunotherapy being explored in targeting macrophages.

Clinical immunology and immunotherapy for hepatocellular carcinoma: current progress and challenges

At the time of hepatocellular carcinoma (HCC) diagnosis, patients are most often at an advanced stage; however, the current treatment regimens remain unsatisfactory. Thus, novel and more powerful therapeutic approaches for advanced HCC are urgently required. Exacerbation of immunotolerant signals and/or escaping immunosurveillance leads to the development of HCC, which appears to be a rational reason to use immunotherapy to restore anticancer immunity. Several novel immunotherapeutic methods, including the use of immune checkpoint inhibitors, new types of immune cell adoption [e.g., chimeric antigen receptor T cell (CAR-T), TCR gene-modified T cells and stem cells], and microRNAs have been used in clinical trials for the treatment of HCC. However, some crucial issues remain to be addressed for such novel immunotherapy techniques. Finally, immunotherapy is now standing on the threshold of great advances in the fight against HCC.

Individualized precision treatment: Targeting TAM in HCC

Tumor-associated macrophage (TAM) plays a prominent role in inflammatory microenvironment which contributes to hepatocellular carcinoma (HCC) progress by presenting M1 and M2 polarization. HCC, which is highly associated with inflammation, always leads to poor prognosis for recurrence and metastasis. TAMs with M2 polarization induce cellular proliferation, angiogenesis, epithelial-mesenchymal transition (EMT) in HCC. Furthermore, it also interacts with other immune cell clusters which leads to the resistance in targeted therapy and immunotherapy. This article reviews studies on the role of TAM to affect HCC treatment and provides insight into the potential individualized precision monotherapy or combination therapy in HCC.

miR-98-5p Alleviated Epithelial-to-Mesenchymal Transition and Renal Fibrosis via Targeting Hmga2 in Diabetic Nephropathy

Recently, microRNAs have been recognized as crucial regulators of diabetic nephropathy (DN) development. Epithelial-to-mesenchymal transition (EMT) can play a significant role in tubulointerstitial fibrosis, and it is a hallmark of diabetic nephropathy progression. Nevertheless, the function of miR-98-5p in the modulation of EMT and renal fibrosis during DN remains barely investigated. Hence, identifying the mechanisms of miR-98-5p in regulating EMT and fibrosis is of huge significance. In our present research, decreased miR-98-5p was demonstrated in db/db mice and mice mesangial cells treated with the high dose of glucose. Meanwhile, activated EMT and increased fibrosis was accompanied with the decrease of miR-98-5p in vitro and in vivo. Additionally, to further find out the roles of miR-98-5p in DN development, overexpression of miR-98-5p was applied. Firstly, in vivo investigation exhibited that elevation of miR-98-5p restrained proteinuria, serum creatinine, BUN, the EMT process, and fibrosis. Furthermore, high glucose was able to promote mice mesangial cell proliferation, EMT process, and induced renal fibrosis, which could be prevented by overexpression of miR-98-5p. Moreover, high mobility group A (HMGA2) can exhibit an important role in diverse biological processes. Here, HMGA2 was investigated as a target of miR-98-5p currently. Luciferase reporter assay was conducted and the correlation of miR-98-5p and HMGA2 was validated. Moreover, it was displayed that HMGA2 was remarkably elevated in db/db mice and mice mesangial cells. Furthermore, miR-98-5p strongly depressed HMGA2 protein and mRNA levels in mice mesangial cells. Overall, these revealed miR-98-5p could suppress the EMT process and renal fibrosis through targeting HMGA2 in DN.

lncRNA GAS5 promotes M1 macrophage polarization via miR-455-5p/SOCS3 pathway in childhood pneumonia

OBJECTIVES

We herein aimed to explore whether growth arrest-specific 5 (GAS5) promotes M1 macrophage polarization in childhood pneumonia and to investigate the underlying mechanism.

METHODS

Relative GAS5 and miR-455-5p expression and suppressor of cytokine signaling 3 (SOCS3) messenger RNA level were examined using quantitative reverse transcription polymerase chain reaction. Protein expression of SOCS3 and the Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway-related proteins was detected using western blot analysis. Luciferase activity assay was performed to test whether miR-455-5p could bind to GAS5 or SOCS3. The macrophage phenotype was determined using flow cytometry analysis and enzyme-linked immunosorbent assay.

RESULTS

The macrophage polarization toward the M2 phenotype was observed in peripheral blood from pneumonia children. Furthermore, GAS5 and SOCS3 expression were upregulated but miR-455-5p downregulated in human monocyte-derived macrophages from pneumonia children compared with the control group. Furthermore, GAS5 acted as a sponge for miR-455-5p to facilitate SOCS3 expression. Moreover, miR-455-5p mimic and SOCS3 knockdown significantly reversed the GAS5 overexpression-mediated suppression of the JAK2/STAT3 signaling and promotion of M1 polarization.

CONCLUSION

GAS5 promotes M1 macrophage polarization by acting as a competing endogenous RNA of miR-455-5p to facilitate SOCS3 expression in childhood pneumonia.

NFAT1 enhances the effects of tumor-associated macrophages on promoting malignant melanoma growth and metastasis

Tumor-associated macrophages (TAMs) play substantial roles in tumor growth, invasion, and metastasis. Nuclear factor of activated T cell (NFAT1) has been shown to promote melanoma growth and metastasis in vivo We herein aim to investigate whether NFAT1 is capable to promote melanoma growth and metastasis by influencing TAM properties. Melanoma-conditioned TAMs were obtained from human monocytes after incubation with conditioned medium from A375 cell culture. The phenotype of the macrophages was detected. Cell proliferation, migration, and invasion were evaluated. Human malignant melanoma tissues exhibited increased CD68+-macrophage infiltration and NFAT1 expression compared with the normal pigmented nevus tissues. Melanoma-conditioned TAMs displayed M2-like phenotype. Melanoma-conditioned TAMs also promoted proliferation, migration, and invasion of human malignant melanoma cell lines A375 and WM451. Furthermore, NFAT1 expression in TAMs was significantly increased compared with the M0 group. NFAT1 overexpression significantly strengthened the melanoma-conditioned TAM-mediated promotion of cell migration and invasion in A375 and WM451 cells, whereas NFAT1 knockdown exerted the opposite effects. Moreover, NFAT1 overexpression in melanoma-conditioned TAMs promoted CD68+-macrophage infiltration, tumor growth, and metastasis in vivo NFAT1 may play a critical role in enhancing the TAM-mediated promotion of growth and metastasis in malignant melanoma.