Hepatocellular carcinoma is accelerated by NASH involving M2 macrophage polarization mediated by hif-1induced IL-10

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.

The cellular-centered view of hypoxia tumor microenvironment: Molecular mechanisms and therapeutic interventions

Cancer is a profoundly dynamic, heterogeneous and aggressive systemic ailment, with a coordinated evolution of various types of tumor niches. Hypoxia plays an indispensable role in the tumor micro-ecosystem, drastically enhancing the plasticity of cancer cells, fibroblasts and immune cells and orchestrating intercellular communication. Hypoxia-induced signals, particularly hypoxia-inducible factor-1α (HIF-1α), drive the reprogramming of genetic, transcriptional, and proteomic profiles. This leads to a spectrum of interconnected processes, including augmented survival of cancer cells, evasion of immune surveillance, metabolic reprogramming, remodeling of the extracellular matrix, and the development of resistance to conventional therapeutic modalities like radiotherapy and chemotherapy. Here, we summarize the latest research on the multifaceted effects of hypoxia, where a multitude of cellular and non-cellular elements crosstalk with each other and co-evolve in a synergistic manner. Additionally, we investigate therapeutic approaches targeting hypoxic niche, encompassing hypoxia-activated prodrugs, HIF inhibitors, nanomedicines, and combination therapies. Finally, we discuss some of the issues to be addressed and highlight the potential of emerging technologies in the treatment of cancer.

LncRNAs act as modulators of macrophages within the tumor microenvironment

Long non-coding RNAs (lncRNAs) have been established as pivotal players in various cellular processes, encompassing the regulation of transcription, translation and post-translational modulation of proteins, thereby influencing cellular functions. Notably, lncRNAs exert a regulatory influence on diverse biological processes, particularly in the context of tumor development. Tumor-associated macrophages (TAMs) exhibit the M2 phenotype, exerting significant impact on crucial processes such as tumor initiation, angiogenesis, metastasis and immune evasion. Elevated infiltration of TAMs into the tumor microenvironment (TME) is closely associated with a poor prognosis in various cancers. LncRNAs within TAMs play a direct role in regulating cellular processes. Functioning as integral components of tumor-derived exosomes, lncRNAs prompt the M2-like polarization of macrophages. Concurrently, reports indicate that lncRNAs in tumor cells contribute to the expression and release of molecules that modulate TAMs within the TME. These actions of lncRNAs induce the recruitment, infiltration and M2 polarization of TAMs, thereby providing critical support for tumor development. In this review, we survey recent studies elucidating the impact of lncRNAs on macrophage recruitment, polarization and function across different types of cancers.

Targeting squalene epoxidase restores anti-PD-1 efficacy in metabolic dysfunction-associated steatohepatitis-induced hepatocellular carcinoma

OBJECTIVE

Squalene epoxidase (SQLE) promotes metabolic dysfunction-associated steatohepatitis-associated hepatocellular carcinoma (MASH-HCC), but its role in modulating the tumour immune microenvironment in MASH-HCC remains unclear.

DESIGN

We established hepatocyte-specific Sqle transgenic (tg) and knockout mice, which were subjected to a choline-deficient high-fat diet plus diethylnitrosamine to induce MASH-HCC. SQLE function was also determined in orthotopic and humanised mice. Immune landscape alterations of MASH-HCC mediated by SQLE were profiled by single-cell RNA sequencing and flow cytometry.

RESULTS

Hepatocyte-specific Sqle tg mice exhibited a marked increase in MASH-HCC burden compared with wild-type littermates, together with decreased tumour-infiltrating functional IFN-γ+ and Granzyme B+ CD8+ T cells while enriching Arg-1+ myeloid-derived suppressor cells (MDSCs). Conversely, hepatocyte-specific Sqle knockout suppressed tumour growth with increased cytotoxic CD8+ T cells and reduced Arg-1+ MDSCs, inferring that SQLE promotes immunosuppression in MASH-HCC. Mechanistically, SQLE-driven cholesterol accumulation in tumour microenvironment underlies its effect on CD8+ T cells and MDSCs. SQLE and its metabolite, cholesterol, impaired CD8+ T cell activity by inducing mitochondrial dysfunction. Cholesterol depletion in vitro abolished the effect of SQLE-overexpressing MASH-HCC cell supernatant on CD8+ T cell suppression and MDSC activation, whereas cholesterol supplementation had contrasting functions on CD8+ T cells and MDSCs treated with SQLE-knockout supernatant. Targeting SQLE with genetic ablation or pharmacological inhibitor, terbinafine, rescued the efficacy of anti-PD-1 treatment in MASH-HCC models.

CONCLUSION

SQLE induces an impaired antitumour response in MASH-HCC via attenuating CD8+ T cell function and augmenting immunosuppressive MDSCs. SQLE is a promising target in boosting anti-PD-1 immunotherapy for MASH-HCC.

The dynamic shifts of IL-10-producing Th17 and IL-17-producing Treg in health and disease: a crosstalk between ancient "Yin-Yang" theory and modern immunology

The changes in T regulatory cell (Treg) and T helper cell (Th) 17 ratios holds paramount importance in ensuring internal homeostasis and disease progression. Recently, novel subsets of Treg and Th17, namely IL-17-producing Treg and IL-10-producing Th17 have been identified. IL-17-producing Treg and IL-10-producing Th17 are widely considered as the intermediates during Treg/Th17 transformation. These "bi-functional" cells exhibit plasticity and have been demonstrated with important roles in multiple physiological functions and disease processes. Yin and Yang represent opposing aspects of phenomena according to the ancient Chinese philosophy "Yin-Yang" theory. Furthermore, Yin can transform into Yang, and vice versa, under specific conditions. This theory has been widely used to describe the contrasting functions of immune cells and molecules. Therefore, immune-activating populations (Th17, M1 macrophage, etc.) and immune overreaction (inflammation, autoimmunity) can be considered Yang, while immunosuppressive populations (Treg, M2 macrophage, etc.) and immunosuppression (tumor, immunodeficiency) can be considered Yin. However, another important connotation of "Yin-Yang" theory, the conversion between Yin and Yang, has been rarely documented in immune studies. The discovery of IL-17-producing Treg and IL-10-producing Th17 enriches the meaning of "Yin-Yang" theory and further promotes the relationship between ancient "Yin-Yang" theory and modern immunology. Besides, illustrating the functions of IL-17-producing Treg and IL-10-producing Th17 and mechanisms governing their differentiation provides valuable insights into the mechanisms underlying the dynamically changing statement of immune statement in health and diseases.

TAM-Hijacked Immunoreaction Rescued by Hypoxia-Pathway-Intervened Strategy for Enhanced Metastatic Cancer Immunotherapy

Immunotherapy is regarded as a prospective strategy against metastatic cancer. However, tumor-associated macrophages (TAMs), which accumulate in hypoxic tumor microenvironment, reduce the effectiveness of immunotherapy by blocking or "hijacking" the initiation of the immune response. Here, a novel tumor-targeted nanoplatform loaded with hypoxia-pathway-intervened docosahexaenoic acid (DHA) and chemotherapeutic drug carfilzomib (CFZ) is developed, which realizes the rescue of TAM-hijacked immune response and effective metastatic cancer immunotherapy. DHA is conjugated to fucoidan (Fuc) via a reduction cleavable selenylsulfide bond (SSe) for micelle preparation, and CFZ is encapsulated in the hydrophobic cores of micelles. The functionalized nanoplatforms (Fuc─SSe─DHA (FSSeD)-CFZs) induce immunogenic cell death, inhibit hypoxia-inducible factor-1α expression, and improve immunosuppression by TAM suppression. FSSeD-CFZs enhance immune response against primary tumor development and metastasis formation. In brief, the novel rescue strategy for TAM-hijacked immunoreaction by inhibiting hypoxia pathway has the potential and clinically translational significance for enhanced metastatic cancer immunotherapy.

EgCF mediates macrophage polarisation by influencing the glycolytic pathway

Human cystic echinococcosis (CE) is a zoonotic disorder triggered by the larval stage of Echinococcus granulosus (E. granulosus) and predominantly occurred in the liver and lungs. The M2 macrophage level is considerably elevated among the liver of patients with hepatic CE and performs an integral function in liver fibrosis. However, the mechanism of CE inducing polarisation of macrophage to an M2 phenotype is unknown. In this study, macrophage was treated with E. granulosus cyst fluid (EgCF) to explore the mechanism of macrophage polarisation. Consequently, the expression of the M2 macrophage and production of anti-inflammatory cytokines increased after 48 h treatment by EgCF. In addition, EgCF promoted polarisation of macrophage to an M2 phenotype by inhibiting the expression of transcriptional factor hypoxia-inducible factor 1-alpha (HIF-1α), which increased the expression of glycolysis-associated genes, including hexokinase 2 (HK2) and pyruvate kinase 2 (PKM2). The HIF-1α agonist ML228 also inhibited the induction of macrophage to an M2 phenotype by EgCF in vitro. Our findings indicate that E. granulosus inhibits glycolysis by suppressing the expression of HIF-1α.

Intratumoral PPT1-positive macrophages determine immunosuppressive contexture and immunotherapy response in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is a malignancy with limited treatment options and poor prognosis. Macrophages are enriched in the HCC microenvironment and have a significant impact on disease progression and therapy efficacy. We aim to identify critical macrophages subsets involved in HCC development.

METHODS

Macrophage-specific marker genes were identified through single-cell RNA sequencing analyses. The clinical significance of macrophages with palmitoyl-protein thioesterase 1 (PPT1) positive was investigated in 169 patients with HCC from Zhongshan Hospital using immunohistochemistry and immunofluorescence. The immune microenvironment of HCC and the functional phenotype of PPT1+ macrophages were explored using cytometry by time-of-flight (CyTOF) and RNA sequencing.

RESULTS

Single-cell RNA sequencing analyses revealed that PPT1 was predominantly expressed in macrophages in HCC. Intratumoral PPT1+ macrophages abundance was associated with inferior survival durations of patients and an independent risk factor of prognosis for HCC. High throughput analyses of immune infiltrates showed that PPT1+ macrophage-enriched HCCs were characterized by high infiltration of CD8+ T cells with increased programmed death-1 (PD-1) expression. PPT1+ macrophages exhibited higher galectin-9, CD172a, and CCR2 levels but lower CD80 and CCR7 levels than PPT1- macrophages. Pharmacological inhibition of PPT1 by DC661 suppressed mitogen-activated protein kinase (MAPK) pathway activity but activated nuclear factor kappa B (NF-κB) pathway in macrophages. In addition, DC661 enhanced the therapeutic efficacy of anti-PD-1 antibody in the HCC mouse model.

CONCLUSIONS

PPT1 is mainly expressed in macrophages in HCC and promotes immunosuppressive transformation of macrophages and tumor microenvironment. PPT1+ macrophage infiltration is associated with poor prognosis of patients with HCC. Targeting PPT1 may potentiate the efficacy of immunotherapy for HCC.

Regulation of intrinsic and extrinsic metabolic pathways in tumour-associated macrophages

Tumour-associated macrophages (TAMs) are highly plastic and are broadly grouped into two major functional states, namely the pro-inflammatory M1-type and the pro-tumoural M2-type. Conversion of the functional states of TAMs is regulated by various cytokines, chemokines growth factors and other secreted factors in the microenvironment. Dysregulated metabolism is a hallmark of cancer. Emerging evidence suggests that metabolism governs the TAM differentiation and functional conversation in support of tumour growth and metastasis. Aside from the altered metabolism reprogramming in TAMs, extracellular metabolites secreted by cancer, stromal and/or other cells within the tumour microenvironment have been found to regulate TAMs through passive competition for metabolite availability and direct regulation via receptor/transporter-mediated signalling reaction. In this review, we focus on the regulatory roles of different metabolites and metabolic pathways in TAM conversion and function. We also discuss if the dysregulated metabolism in TAMs can be exploited for the development of new therapeutic strategies against cancer.

Soluble CD163 is a predictor of fibrosis and hepatocellular carcinoma development in nonalcoholic steatohepatitis

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease. The serum level of soluble CD163 (sCD163), a macrophage activation marker, is associated with liver tissue changes; however, its prognostic value is unknown. Here, we determined the utility of sCD163 as a marker for hepatocellular carcinoma (HCC) and prognostic marker for NAFLD.

METHODS

This retrospective study obtained data regarding serum sCD163 levels, liver histology, and background factors associated with NAFLD in 287 patients (men/women, 140/147; average age, 53 ± 14 years) with NAFLD who underwent liver biopsy. Repeated liver biopsies of 287 patients with NAFLD (5.0 ± 2.7 years) were compared regarding serum sCD163 levels and liver tissue changes (stage, grade, steatosis, and NAFLD activity score).

RESULTS

Serum sCD163 levels increased with the progression of liver fibrosis and inflammation (both P < 0.05) and were particularly helpful in distinguishing cases of Grade 4 fibrosis (P < 0.001). Levels of sCD163 significantly decreased in patients with NAFLD exhibiting alleviated fibrosis and inflammation (P < 0.05). We could also predict the development of HCC and associated mortality based on serum sCD163 levels at the time of NAFLD diagnosis. Serum sCD163 levels were higher in patients with HCC than in patients without HCC (1074 ± 379 ng/ml vs. 669 ± 261 ng/ml; P < 0.0001), and the same trend was observed for mortality.

CONCLUSIONS

The serum sCD163 level reflects the progression of fibrosis and inflammation in liver tissues, showing much promise as a noninvasive biomarker for nonalcoholic steatohepatitis and NAFLD as well as a possible predictor of HCC development and patient prognosis.

Retinoic acid-loaded PLGA nanocarriers targeting cell cholesterol potentialize the antitumour effect of PD-L1 antibody by preventing epithelial-mesenchymal transition mediated by M2-TAM in colorectal cancer

Tumour-associated macrophages (TAMs) often promote cancer progression through immunosuppression in the tumour microenvironment (TME). However, the signalling pathways crosstalk responsible for this mechanism remain unclear. The aim of our study was to investigate whether the interaction between TAMs and colorectal cancer cells could be down-regulated by nanoparticles (NPs) loaded with retinoic acid (RA) and coated with cholesterol (CHO), in combination with an anti-PD-L1 immune checkpoint inhibitor. Tumours were evaluated by qRT-PCR and immunohistochemistry from allographic tumour growth model. In addition, human tumours were evaluated by Tissue Microarray (TMA) and immunohistochemistry. Complementary analysis of epithelial-mesenchymal transition, cell migration, and macrophage polarisation were evaluated in vitro. We showed that the IL-10R/IL-10 axis is involved in overstimulation of the STAT3 pathway as well as downregulation of the NF-κB signalling pathway, which supports a loop of immunosuppressive cytokines that induces the M2-TAM phenotype. Furthermore, our combined findings suggest that the upregulation of STAT3/NF-κB pathways crosstalk mediated by immunosuppressive cytokines, such as IL-10/PD-L1/TGF-β, via M2-TAMs in the TME, leads to immunosuppression and epithelial-mesenchymal-transition of the colorectal cancer for stimulating Vimentin, CXCL12 and CD163 in the primary tumours. Importantly, NPs holding RA and coated with CHO in combination with anti-PD-L1 were more efficient in blocking this signalling pathway. These results contribute to our understanding of the immunological mechanisms, especially the re-educating of TAMs, and provide a novel management strategy for aggressive colorectal cancers using anti-PD-L1-conjugated nanocarriers.

Osthole regulates N6-methyladenosine-modified TGM2 to inhibit the progression of rheumatoid arthritis and associated interstitial lung disease

Rheumatoid arthritis (RA) is an inflammatory autoimmune disease, and RA interstitial lung disease (ILD) is a severe complication of RA. This investigation aims to determine the effect and underlying mechanism of osthole (OS), which could be extracted from Cnidium, Angelica, and Citrus plants and evaluate the role of transglutaminase 2 (TGM2) in RA and RA-ILD. In this work, OS downregulated TGM2 to exert its additive effect with methotrexate and suppress the proliferation, migration, and invasion of RA-fibroblast-like synoviocytes (FLS) by attenuating NF-κB signaling, resulting in the suppression of RA progression. Interestingly, WTAP-mediated N6-methyladenosine modification of TGM2 and Myc-mediated WTAP transcription cooperatively contributed to the formation of a TGM2/Myc/WTAP-positive feedback loop through upregulating NF-κB signaling. Moreover, OS could downregulate the activation of the TGM2/Myc/WTAP-positive feedback circuit. Furthermore, OS restrained the proliferation and polarization of M2 macrophages to inhibit the aggregation of lung interstitial CD11b⁺ macrophages, and the effectiveness and non-toxicity of OS in suppressing RA and RA-ILD progression were verified in vivo. Finally, bioinformatics analyses validated the importance and the clinical significance of the OS-regulated molecular network. Taken together, our work emphasized OS as an effective drug candidate and TGM2 as a promising target for RA and RA-ILD treatment.

Role of ubiquitin regulatory X domain‑containing protein 3B in the development of hepatocellular carcinoma (Review)

The majority of new cases and fatalities from hepatocellular carcinoma (HCC) occur in China; however, the overall morbidity and mortality rates are decreasing. A major risk factor due to the evolving epidemiology is improper lipid metabolism. Although investigations on aberrant lipid metabolism are numerous, there are only a limited number of studies available on proteasomal degradation processes. The degradation process is mainly involved in endoplasmic reticulum stabilization, the balance of lipid metabolism, and physiological functions of Golgi apparatus, endoplasmic reticulum, lysosomes and other organelles, however, this process has been little studied in the development of tumorigenesis. In order to provide some theoretical support for future research on ubiquitin regulatory X domain‑containing protein 3B (UBXN3B), the present review focuses on the role of UBXN3B, which is involved in the stabilization of the endoplasmic reticulum and the maintenance of lipid homeostasis, as well as in the promotion and development of non‑alcoholic fatty liver disease and HCC.

Immunometabolic attributes and mitochondria-associated signaling of Tumor-Associated Macrophages in tumor microenvironment modulate cancer progression

Macrophages are specialized immune cells, which have the capacity to phagocytize and destroy the target cells, including tumor cells. Some macrophages, however on their way to devour the cancer cells undergo a change due to a complex set of signaling pathways. They are induced to change into a polarized state known as M2. The M2 macrophages help in metastasis, tumor suppression, and angiogenesis. The macrophage which gets associated with this TME, are referred to as tumor-associated macrophages (TAMs). TAMS undergo a metabolic reprogramming toward oxidative metabolism for bioenergetic purposes (OXPHOS), fatty acid oxidation (FAO), decreased glycolysis, decreased metabolism via the PPP, and upregulation of arginase 1 (ARG1) which triggers immunosuppressive pro-tumor signaling in the tumor microenvironment (TME) in which mitochondria plays an instrumental role. Reports have suggested that a complex series of interactions and exchange of materials, such as cytokines, metabolic intermediates and sometimes even transfer of mitochondria take place between TAMS and other TME components most importantly cancer cells that reprogram their metabolism to encourage cell growth, division, epithelial to mesenchymal transition, that ultimately play an important role in tumor progression. This review will try to focus on the crosstalk between the TAMs with several other components of TME, what instrumental role mitochondria play in that and also try to explore some of the therapeutic options available in cancer patients.

Major pathways involved in macrophage polarization in cancer

Macrophages play an important role in tissue homeostasis, tissue remodeling, immune response, and progression of cancer. Consequently, macrophages exhibit significant plasticity and change their transcriptional profile and function in response to environmental, tissue, and inflammatory stimuli resulting in pro- and anti-tumor effects. Furthermore, the categorization of tissue macrophages in inflammatory situations remains difficult; however, there is an agreement that macrophages are predominantly polarized into two different subtypes with pro- and anti-inflammatory properties, the so-called M1-like and M2-like macrophages, respectively. These two macrophage classes can be considered as the extreme borders of a continuum of many intermediate subsets. On one end, M1 are pro-inflammatory macrophages that initiate an immunological response, damage tissue integrity, and dampen tumor progression by fostering robust T and natural killer (NK) cell anti-tumoral responses. On the other end, M2 are anti-inflammatory macrophages involved in tissue remodeling and tumor growth, that promote cancer cell proliferation, invasion, tumor metastasis, angiogenesis and that participate to immune suppression. These decisive roles in tumor progression occur through the secretion of cytokines, chemokines, growth factors, and matrix metalloproteases, as well as by the expression of immune checkpoint receptors in the case of M2 macrophages. Moreover, macrophage plasticity is supported by stimuli from the Tumor Microenvironment (TME) that are relayed to the nucleus through membrane receptors and signaling pathways that result in gene expression reprogramming in macrophages, thus giving rise to different macrophage polarization outcomes. In this review, we will focus on the main signaling pathways involved in macrophage polarization that are activated upon ligand-receptor recognition and in the presence of other immunomodulatory molecules in cancer.

Hypoxia as a Modulator of Inflammation and Immune Response in Cancer

A clear association between hypoxia and cancer has heretofore been established; however, it has not been completely developed. In this sense, the understanding of the tumoral microenvironment is critical to dissect the complexity of cancer, including the reduction in oxygen distribution inside the tumoral mass, defined as tumoral hypoxia. Moreover, hypoxia not only influences the tumoral cells but also the surrounding cells, including those related to the inflammatory processes. In this review, we analyze the participation of HIF, NF-κB, and STAT signaling pathways as the main components that interconnect hypoxia and immune response and how they modulate tumoral growth. In addition, we closely examine the participation of the immune cells and how they are affected by hypoxia, the effects of the progression of cancer, and some innovative applications that take advantage of this knowledge, to suggest potential therapies. Therefore, we contribute to the understanding of the complexity of cancer to propose innovative therapeutic strategies in the future.

Reprogramming the tumor microenvironment by genome editing for precision cancer therapy

The tumor microenvironment (TME) is essential for immune escape by tumor cells. It plays essential roles in tumor development and metastasis. The clinical outcomes of tumors are often closely related to individual differences in the patient TME. Therefore, reprogramming TME cells and their intercellular communication is an attractive and promising strategy for cancer therapy. TME cells consist of immune and nonimmune cells. These cells need to be manipulated precisely and safely to improve cancer therapy. Furthermore, it is encouraging that this field has rapidly developed in recent years with the advent and development of gene editing technologies. In this review, we briefly introduce gene editing technologies and systematically summarize their applications in the TME for precision cancer therapy, including the reprogramming of TME cells and their intercellular communication. TME cell reprogramming can regulate cell differentiation, proliferation, and function. Moreover, reprogramming the intercellular communication of TME cells can optimize immune infiltration and the specific recognition of tumor cells by immune cells. Thus, gene editing will pave the way for further breakthroughs in precision cancer therapy.

Tumor-derived extracellular vesicles containing long noncoding RNA PART1 exert oncogenic effect in hepatocellular carcinoma by polarizing macrophages into M2

AIM

We explored whether tumor-derived extracellular vesicles (EVs) could deliver long noncoding RNA (lncRNA) PART1 into macrophage to orchestrate macrophage polarization in the progression of hepatocellular carcinoma (HCC).

METHOD

The expression patterns of PART1, microRNA (miR)-372-3p and TLR4 were detected by RT-qPCR in the HCC tissues and HCC cells. PART1 was silenced or overexpressed in HCC cells to assess its effects on the HCC cell process. EVs were isolated from PART1-overexpressed HCC cells, and co-cultured with macrophages, and gain- and loss-of-function assays were implemented in macrophages to evaluate their role in macrophage polarization. Relationship among PART1, miR-372-3p, and TLR4 was evaluated. Effect of EV-PART1 on tumorigenicity in vivo was detected by subcutaneous tumorigenicity test in nude mice.

RESULT

PART1 and TLR4 were upregulated while miR-372-3p was downregulated in HCC tissues and cells. PART1 increased HCC cell proliferation, migration, invasion, and EMT. Mechanistically, PART1 bound to miR-372-3p to downregulate its expression, whereas TLR4 was negatively targeted by miR-372-3p in the macrophages. EVs containing PART1, TLR4 overexpression, or miR-372-3p inhibition induced M2 polarization of macrophages. Also, EVs containing PART1 promoted M2 polarization of macrophages and the occurrence of HCC by affecting miR-372-3p/TLR4 axis.

CONCLUSION

HCC cell-derived EVs might up-regulate TLR4 by inhibiting miR-372-3p via PART1 delivery to promote macrophage M2 polarization in HCC.

T cells: Friends and foes in NASH pathogenesis and hepatocarcinogenesis

In association with the pandemic spreading of obesity and metabolic syndrome, the prevalence of NAFLD-related HCC is increasing almost exponentially. In recent years, many of the underlining multifactorial causes of NAFLD have been identified, and the cellular mechanisms sustaining disease development have been dissected up to the single-cell level. However, there is still an urgent need to provide clinicians with more therapeutic targets, with particular attention on NAFLD-induced HCC, where immune checkpoint inhibitors do not work as efficiently. Whereas much effort has been invested in elucidating the role of innate immune response in the hepatic NAFLD microenvironment, only in the past decade have novel critical roles been unraveled for T cells in driving chronic inflammation toward HCC. The metabolic and immune microenvironment interact to recreate a tumor-promoting and immune-suppressive terrain, responsible for resistance to anticancer therapy. In this article, we will review the specific functions of several T-cell populations involved in NAFLD and NAFLD-driven HCC. We will illustrate the cellular crosstalk with other immune cells, regulatory networks or stimulatory effects of these interactions, and role of the metabolic microenvironment in influencing immune cell functionality. Finally, we will present the pros and cons of the current therapeutic strategies against NAFLD-related HCC and delineate possible novel approaches for the future.

M1 macrophage-derived exosomes and their key molecule lncRNA HOTTIP suppress head and neck squamous cell carcinoma progression by upregulating the TLR5/NF-κB pathway

Exosomes serve as a crucial mode of communication between tumor-associated macrophages (TAMs) and cancer cells. This study attempted to explore the function of M1-derived exosomes and clarify their specific mechanism in head and neck squamous cell carcinoma (HNSCC). Moreover, the functional roles of M1-derived exosomes and their key molecule long noncoding RNA (lncRNA) HOXA transcript at the distal tip (HOTTIP) in HNSCC were investigated by conducting a series of in vitro and in vivo experiments. The dual-luciferase test was utilized to clarify the binding capacities between HOTTIP/mRNA and miRNAs. Accordingly, HOTTIP was found to be upregulated in M1-derived exosomes. Meanwhile, the in vitro experiments indicated that M1 exosomes suppressed proliferation, migration and invasion but induced apoptosis of cancer cells. This function was noted to be enhanced by HOTTIP-overexpressed M1 exosomes but was weakened by HOTTIP-knockdown ones, indicating that HOTTIP serves as a key molecule in M1 exosomes. Therefore, the function of HOTTIP in cancer cells was explored, for which overexpression of HOTTIP was found to inhibit proliferation, migration and invasion but induced apoptosis of cancer cells in vitro. A mechanism study further showed that M1 exosomes and HOTTIP activated the TLR5/NF-κB signaling pathway by competitively sponging miR-19a-3p and miR-19b-3p. Furthermore, cancer cells expressing HOTTIP were noted to induce the polarization of both local M1 and M2 macrophages; however, M1 exosomes were observed to reprogram local TAMs into M1 macrophages. More importantly, both cancer cells expressing HOTTIP and M1 exosomes reeducated circulating monocytes to express the M1 phenotype. The corresponding data demonstrated that the M1 exosomal lncRNA HOTTIP suppresses HNSCC progression by upregulating the TLR5/NF-κB signaling pathway through competitively sponging miR-19a-3p and miR-19b-3p. In particular, M1 exosomes and HOTTIP induce the polarization of M1 in circulating monocytes, thus providing novel insight into HNSCC immunotherapy.

Immune and Metabolic Alterations in Liver Fibrosis: A Disruption of Oxygen Homeostasis?

According to the WHO, “cirrhosis of the liver” was the 11th leading cause of death globally in 2019. Many kinds of liver diseases can develop into liver cirrhosis, and liver fibrosis is the main pathological presentation of different aetiologies, including toxic damage, viral infection, and metabolic and genetic diseases. It is characterized by excessive synthesis and decreased decomposition of extracellular matrix (ECM). Hepatocyte cell death, hepatic stellate cell (HSC) activation, and inflammation are crucial incidences of liver fibrosis. The process of fibrosis is also closely related to metabolic and immune disorders, which are usually induced by the destruction of oxygen homeostasis, including mitochondrial dysfunction, oxidative stress, and hypoxia pathway activation. Mitochondria are important organelles in energy generation and metabolism. Hypoxia-inducible factors (HIFs) are key factors activated when hypoxia occurs. Both are considered essential factors of liver fibrosis. In this review, the authors highlight the impact of oxygen imbalance on metabolism and immunity in liver fibrosis as well as potential novel targets for antifibrotic therapies.

Macrophage MerTK promotes profibrogenic cross-talk with hepatic stellate cells via soluble mediators

Background & Aims

Activation of Kupffer cells and recruitment of monocytes are key events in fibrogenesis. These cells release soluble mediators which induce the activation of hepatic stellate cells (HSCs), the main fibrogenic cell type within the liver. Mer tyrosine kinase (MerTK) signaling regulates multiple processes in macrophages and has been implicated in the pathogenesis of non-alcoholic steatohepatitis-related fibrosis. In this study, we explored if MerTK activation in macrophages influences the profibrogenic phenotype of HSCs.

Methods

Macrophages were derived from THP-1 cells or differentiated from peripheral blood monocytes towards MerTK⁺/CD206⁺/CD163⁺/CD209^- macrophages. The role of MerTK was assessed by pharmacologic and genetic inhibition. HSC migration was determined in Boyden chambers, viability was measured by the MTT assay, and proliferation was evaluated by the BrdU incorporation assay.

Results

Gas-6 induced MerTK phosphorylation and Akt activation in macrophages, and these effects were inhibited by UNC569. During polarization, MerTK⁺/CD206⁺/CD163⁺/CD209^- macrophages exhibited activation of STAT3, ERK1/2, p38 and increased expression of VEGF-A. Activation of MerTK in THP-1 macrophages induced a secretome which promoted a significant increase in migration, proliferation, viability and expression of profibrogenic factors in HSCs. Similarly, conditioned medium from MerTK⁺ macrophages induced a significant increase in cell migration, proliferation, STAT3 and p38 phosphorylation and upregulation of IL-8 expression in HSCs. Moreover, conditioned medium from Gas-6-stimulated Kupffer cells induced a significant increase in HSC proliferation. These effects were specifically related to MerTK expression and activity in macrophages, as indicated by pharmacologic inhibition and knockdown experiments.

Conclusions

MerTK activation in macrophages modifies the secretome to promote profibrogenic features in HSCs, implicating this receptor in the pathogenesis of hepatic fibrosis.

Lay summary

Fibrosis represents the process of scarring occurring in patients with chronic liver diseases. This process depends on production of scar tissue components by a specific cell type, named hepatic stellate cells, and is regulated by interaction with other cells. Herein, we show that activation of MerTK, a receptor present in a population of macrophages, causes the production of factors that act on hepatic stellate cells, increasing their ability to produce scar tissue.

•

MerTK, a member of the TAM family of proteins, is highly expressed in MerTK⁺/CD206⁺/CD163⁺/CD209^- macrophages.

•

In these macrophages, activation of MerTK induces phosphorylation of Akt, STAT3, ERK1/2, p38 and increased expression of VEGF-A.

•

MerTK activation in macrophages modulates the secretome to promote the profibrogenic phenotype of human HSCs.

•

Profibrogenic effects of macrophages expressing high levels of MerTK were blocked by knockdown or inhibition of MerTK.

Tumor Associated Macrophages: Origin, Recruitment, Phenotypic Diversity, and Targeting

The tumor microenvironment (TME) is known to have a strong influence on tumorigenesis, with various components being involved in tumor suppression and tumor growth. A protumorigenic TME is characterized by an increased infiltration of tumor associated macrophages (TAMs), where their presence is strongly associated with tumor progression, therapy resistance, and poor survival rates. This association between the increased TAMs and poor therapeutic outcomes are stemming an increasing interest in investigating TAMs as a potential therapeutic target in cancer treatment. Prominent mechanisms in targeting TAMs include: blocking recruitment, stimulating repolarization, and depletion methods. For enhancing targeting specificity multiple nanomaterials are currently being explored for the precise delivery of chemotherapeutic cargo, including the conjugation with TAM-targeting peptides. In this paper, we provide a focused literature review of macrophage biology in relation to their role in tumorigenesis. First, we discuss the origin, recruitment mechanisms, and phenotypic diversity of TAMs based on recent investigations in the literature. Then the paper provides a detailed review on the current methods of targeting TAMs, including the use of nanomaterials as novel cancer therapeutics.

Metabolic Reprogramming in the Tumor Microenvironment With Immunocytes and Immune Checkpoints

Immune checkpoint inhibitors (ICIs), Ipilimumab, Nivolumab, Pembrolizumab and Atezolizumab, have been applied in anti-tumor therapy and demonstrated exciting performance compared to conventional treatments. However, the unsatisfactory response rates, high recurrence and adaptive resistance limit their benefits. Metabolic reprogramming appears to be one of the crucial barriers to immunotherapy. The deprivation of required nutrients and altered metabolites not only promote tumor progression but also confer dysfunction on immune cells in the tumor microenvironment (TME). Glycolysis plays a central role in metabolic reprogramming and immunoregulation in the TME, and many therapies targeting glycolysis have been developed, and their combinations with ICIs are in preclinical and clinical trials. Additional attention has been paid to the role of amino acids, lipids, nucleotides and mitochondrial biogenesis in metabolic reprogramming and clinical anti-tumor therapy. This review attempts to describe reprogramming metabolisms within tumor cells and immune cells, from the aspects of glycolysis, amino acid metabolism, lipid metabolism, nucleotide metabolism and mitochondrial biogenesis and their impact on immunity in the TME, as well as the significance of targeting metabolism in anti-tumor therapy, especially in combination with ICIs. In particular, we highlight the expression mechanism of programmed cell death (ligand) 1 [PD-(L)1] in tumor cells and immune cells under reprogramming metabolism, and discuss in detail the potential of targeting key metabolic pathways to break resistance and improve the efficacy of ICIs based on results from current preclinical and clinical trials. Besides, we draw out biomarkers of potential predictive value in ICIs treatment from a metabolic perspective.

Tumor-associated macrophages, dendritic cells, and neutrophils: biological roles, crosstalk, and therapeutic relevance

Tumor-associated myeloid cells constitute a series of plastic and heterogeneous cell populations within the tumor microenvironment (TME), and exhibit different phenotypes and functions in response to various microenvironmental signals. In light of promising preclinical data indicating that myeloid-based therapy can effectively suppress tumor growth, a series of novel immune-based therapies and approaches are currently undergoing clinical evaluation. A better understanding of the diversity and functional roles of different myeloid cell subtypes and of how they are associated with TME remodeling may help to improve cancer therapy. Herein, we focus on myeloid cells and discuss how tumor cells can simultaneously reprogram these cells through tumor-derived factors and metabolites. In addition, we discuss the interactions between myeloid cells and other cells in the TME that have the potential to directly or indirectly regulate tumor initiation, invasion, or angiogenesis. We further discuss the current and future potential applications of myeloid cells in the development of focused therapeutic strategies in cancer treatment.

Dendritic Cell Vaccination of Glioblastoma: Road to Success or Dead End

Glioblastomas (GBM) are the most frequent and aggressive malignant primary brain tumor and remains a therapeutic challenge: even after multimodal therapy, median survival of patients is only 15 months. Dendritic cell vaccination (DCV) is an active immunotherapy that aims at inducing an antitumoral immune response. Numerous DCV trials have been performed, vaccinating hundreds of GBM patients and confirming feasibility and safety. Many of these studies reported induction of an antitumoral immune response and indicated improved survival after DCV. However, two controlled randomized trials failed to detect a survival benefit. This raises the question of whether the promising concept of DCV may not hold true or whether we are not yet realizing the full potential of this therapeutic approach. Here, we discuss the results of recent vaccination trials, relevant parameters of the vaccines themselves and of their application, and possible synergies between DCV and other therapeutic approaches targeting the immunosuppressive microenvironment of GBM.

Cholic acid supplementation accelerates the progression of nonalcoholic fatty liver disease to the procarcinogenic state in mice fed a high-fat and high-cholesterol diet

Nonalcoholic fatty liver disease (NAFLD) is one of the major causes of hepatocellular carcinoma (HCC). Although the intracellular cholesterol accumulation has been demonstrated to regulate the gene expression responsible for steatohepatitis, the role played by cholesterol in the development of NAFLD-associated HCC has not been fully elucidated. In this study, using microarray analysis, we investigated the molecular mechanisms governing cholesterol-mediated progression of NAFLD. To ensure hepatic cholesterol accumulation, either a high-fat and high-cholesterol (HFHC) diet or a high-fat and high-cholesterol with cholic acid (HFHCCA) diet was fed to diethylnitrosamine (DEN)-injected C57BL/6J mice for 10 weeks. While an HFHC diet increased hepatic triglyceride levels, an HFHCCA diet induced hepatic cholesterol accumulation by reducing bile acid biosynthesis in DEN-injected mice. Livers from both HFHC and HFHCCA groups exhibited increases in steatosis and necrosis; however, histological features of HCC were not observed in any of the experimental groups. Hepatic gene expression profile of the HFHCCA group was different from those of other groups. Functional analysis showed that cholic acid supplementation upregulated differentially expressed genes (DEGs) associated with inflammation, proliferation, apoptosis, chemical drug response, and cancer signaling pathway. Downregulated DEGs were associated with steroid metabolism, mitochondrial function, and oxidative phosphorylation pathway. Furthermore, hepatic cholesterol accumulation lowered the expression of DEGs associated with energy and macronutrient metabolism, especially amino acid metabolism. In this study, the results of a global gene expression profile demonstrated that feeding the HFHCCA diet to DEN-injected mice accelerated the carcinogenic progression of NAFLD, implicating the critical role played by hepatic accumulation of cholesterol.

Metformin Actions on the Liver: Protection Mechanisms Emerging in Hepatocytes and Immune Cells against NASH-Related HCC

Nonalcoholic fatty liver disease (NAFLD) is strongly linked to the global epidemic of obesity and type 2 diabetes mellitus (T2DM). Notably, NAFLD can progress from the mildest form of simple steatosis to nonalcoholic steatohepatitis (NASH) that increases the risk for hepatocellular carcinoma (HCC), which is a malignancy with a dismal prognosis and rising incidence in the United States and other developed counties, possibly due to the epidemic of NAFLD. Metformin, the first-line drug for T2DM, has been suggested to reduce risks for several types of cancers including HCC and protect against NASH-related HCC, as revealed by epidemical studies on humans and preclinical studies on animal models. This review focuses on the pathogenesis of NASH-related HCC and the mechanisms by which metformin inhibits the initiation and progression of NASH-related HCC. Since the functional role of immune cells in liver homeostasis and pathogenesis is increasingly appreciated in developing anti-cancer therapies on liver malignancies, we discuss both the traditional targets of metformin in hepatocytes and the recently defined effects of metformin on immune cells.

Remodeling of Mitochondrial Plasticity: The Key Switch from NAFLD/NASH to HCC

Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver and the third-leading cause of cancer-related mortality. Currently, the global burden of nonalcoholic fatty liver disease (NAFLD) has dramatically overcome both viral and alcohol hepatitis, thus becoming the main cause of HCC incidence. NAFLD pathogenesis is severely influenced by lifestyle and genetic predisposition. Mitochondria are highly dynamic organelles that may adapt in response to environment, genetics and epigenetics in the liver ("mitochondrial plasticity"). Mounting evidence highlights that mitochondrial dysfunction due to loss of mitochondrial flexibility may arise before overt NAFLD, and from the early stages of liver injury. Mitochondrial failure promotes not only hepatocellular damage, but also release signals (mito-DAMPs), which trigger inflammation and fibrosis, generating an adverse microenvironment in which several hepatocytes select anti-apoptotic programs and mutations that may allow survival and proliferation. Furthermore, one of the key events in malignant hepatocytes is represented by the remodeling of glucidic-lipidic metabolism combined with the reprogramming of mitochondrial functions, optimized to deal with energy demand. In sum, this review will discuss how mitochondrial defects may be translated into causative explanations of NAFLD-driven HCC, emphasizing future directions for research and for the development of potential preventive or curative strategies.

Transcriptome sequencing-based personalized analysis of hepatocellular carcinoma patients with portal vein tumor thrombus

Background

The mechanism of portal vein tumor thrombus (PVTT) in hepatocellular carcinoma (HCC) has been widely studied, and numerous diagnostic and prognostic biomarkers for HCC with PVTT have been identified. We aimed to evaluate the extent to which these biomarkers may aid the personalized precision therapy of HCC with PVTT.

Methods

Matched tissue specimens [primary HCC tumor (PT), adjacent normal (N) liver, and PVTT tissues] were acquired from 3 Chinese HCC patients who underwent surgery at Sun Yat-sen University Cancer Centre between 2019 and 2020. Ribonucleic acid (RNA) sequencing was performed on the 9 tissue samples. GFOLD (generalized fold change) algorithm was used to analyze the differently expressed genes (DEGs) between the PVTT, PT, and normal tissues from each patient. Genes with a P<0.01 and a |GFOLD value| >1 were identified as having significantly different expression.

Results

In total, 3,543, 32,472, and 12,901 tumorigenesis-associated genes, and 2,919, 17,679, and 14,825 metastasis-associated genes, were detected in Patient 1 (P1), Patient 2 (P2), and Patient 3 (P3), respectively. We analyzed the expression levels of genes associated with hypoxia, macrophage recruitment and cancer stem cells (CSCs). The results showed that hypoxia and CSCs may have contributed to tumorigenesis but not to metastasis in P1. We also found the hypoxia microenvironment played an important role in tumorigenesis and metastasis in P2, and CSCs may have contributed to metastasis. Additionally, we found that CSCs played critical roles in metastasis but not in tumorigenesis in P3. The results also showed that the long non-coding RNA (lncRNA) Metastasis-Associated Lung Adenocarcinoma Transcript 1 (MALAT1) was greatly overexpressed in the PTs and PVTT in all 3 patients, and Heart and Neural Crest Derivatives Expressed 2-antisense RNA 1 (HAND2-AS1) was downregulated in PVTT compared with PTs in all 3 patients. Thus, MALAT1 and HAND2-AS1 may be robust biomarkers for metastasis in HCC patients with PVTT.

Conclusions

Tumor-associated macrophages (TAMs)-targeted immunotherapy is a promising therapy for HCC patients with PVTT. LncRNAs MALAT1, and HAND2-AS1 may be promising targets for HCC therapy.

Nanomedicine-based cancer immunotherapies developed by reprogramming tumor-associated macrophages

Tumor microenvironment is a complex ecosystem composed of tumor extracellular matrix, fibroblasts, blood vessels, and immune cells, promoting tumor development by secreting various growth factors, hydrolase, and inflammatory factors. Tumor-associated macrophages (TAMs) constitute the largest number of immune cells in the TME, and they have a "double-edged sword" effect on tumor growth, invasion, metastasis, angiogenesis, and immunosuppression. Under the regulation of different cytokines in the TME, the bidirectional TAMs can switch their phenotypes between tumoricidal M1-like and pro-tumorigenic M2-like macrophages. TAM polarization suggests that scientists can use this property to design drugs targeting this regulation as a promising immunotherapy strategy to enhance tumor therapy efficiency. In this review, we summarize a brief introduction of TAMs and their implications for tumorigenesis. Next, we review recent advances in designing various functionalized nanomedicines and their applications in nanomedicine-based cancer therapies that target TAMs by killing them, inhibiting macrophage recruitment, and repolarizing them from pro-tumorigenic M2-like to tumoricidal M1-like macrophages. Simultaneously, the regulation of nanomedicines on the signaling pathways accounting for these effects is also summarized. This review will not only provide background scientific information for the understanding of TAMs and their roles in cancer treatment but also help scientists design nanomedicines based on tumor TAMs, which can help achieve better clinical treatment outcomes for tumors.

The Degree of Helicobacter pylori Infection Affects the State of Macrophage Polarization through Crosstalk between ROS and HIF-1α

Methods

The expression of CD86, CD206, and HIF-1α in the gastric mucosa was evaluated through immunohistochemistry. RAW 264.7 cells were cocultured with H. pylori at various multiplicities of infection (MOIs), and iNOS, CD86, Arg-1, CD206, and HIF-1α expression was detected by Western blot, PCR, and ELISA analyses. ROS expression was detected with the fluorescent probe DCFH-DA. Macrophages were also treated with the ROS inhibitor NAC or HIF-1α inhibitor YC-1.

Results

Immunohistochemical staining revealed that the macrophage polarization state was associated with the progression of gastric lesions and state of H. pylori infection. The MOI of H. pylori affected macrophage polarization, and H. pylori enhanced the expression of ROS and HIF-1α in macrophages. A low MOI of H. pylori promoted both the M1 and M2 phenotypes, while a high MOI suppressed the M2 phenotype. Furthermore, ROS inhibition attenuated HIF-1α expression and switched macrophage polarization from M1 to M2. However, HIF-1α inhibition suppressed ROS expression and inhibited both the M1 phenotype and the M2 phenotype. Inhibition of ROS or HIF-1α also suppressed the activation of the Akt/mTOR pathway, which was implicated in H. pylori-induced macrophage polarization.

Conclusions

Macrophage polarization is associated with the progression of gastric lesions and state of H. pylori infection. The MOI of H. pylori influences the macrophage polarization state. Crosstalk between ROS and HIF-1α regulates H. pylori-induced macrophage polarization via the Akt/mTOR pathway.

Role of mitochondria in liver metabolic health and diseases

The liver is a major organ that coordinates the metabolic flexibility of the whole body, which is characterized by the ability to adapt dynamically in response to fluctuations in energy needs and supplies. In this context, hepatocyte mitochondria are key partners in fine-tuning metabolic flexibility. Here we review the metabolic and signalling pathways carried by mitochondria in the liver, the major pathways that regulate mitochondrial function and how they function in health and metabolic disorders associated to obesity, i.e. insulin resistance, non-alcoholic steatosis and steatohepatitis and hepatocellular carcinoma. Finally, strategies targeting mitochondria to counteract liver disorders are discussed.

Characteristics of the Tumor Microenvironment That Influence Immune Cell Functions: Hypoxia, Oxidative Stress, Metabolic Alterations

Immunotherapy (IMT) is now a core component of cancer treatment, however, many patients do not respond to these novel therapies. Investigating the resistance mechanisms behind this differential response is now a critical area of research. Immune-based therapies, particularly immune checkpoint inhibitors (ICI), rely on a robust infiltration of T-cells into the tumor microenvironment (TME) for an effective response. While early efforts relied on quantifying tumor infiltrating lymphocytes (TIL) in the TME, characterizing the functional quality and degree of TIL exhaustion correlates more strongly with ICI response. Even with sufficient TME infiltration, immune cells face a harsh metabolic environment that can significantly impair effector function. These tumor-mediated metabolic perturbations include hypoxia, oxidative stress, and metabolites of cellular energetics. Primarily through HIF-1-dependent processes, hypoxia invokes an immunosuppressive phenotype via altered molecular markers, immune cell trafficking, and angiogenesis. Additionally, oxidative stress can promote lipid peroxidation, ER stress, and Treg dysfunction, all associated with immune dysregulation. Finally, the metabolic byproducts of lipids, amino acids, glucose, and cellular energetics are associated with immunosuppression and ICI resistance. This review will explore these biochemical pathways linked to immune cell dysfunction in the TME and highlight potential adjunctive therapies to be used alongside current IMT.

Hepatic metabolic adaptation and adipose tissue expansion are altered in mice with steatohepatitis induced by high-fat high sucrose diet

BACKGROUND

Obesity is a chronic progressive disease with several metabolic alterations. Nonalcoholic fatty liver disease (NAFLD) is an important comorbidity of obesity that can progress to nonalcoholic steatohepatitis (NASH), cirrhosis or hepatocarcinoma. This study aimed at clarifying the molecular mechanisms underlying the metabolic alterations in hepatic and adipose tissue during high-fat high-sucrose diet-induced NAFLD development in mice.

METHODS

Twenty-four male mice (C57BL/6J) were randomly allocated into 3 groups (n = 8 mice per group) to receive a chow diet, a high-fat diet (HFD), or a high-fat high-sucrose diet (HF-HSD) for 20 weeks. At sacrifice, liver and adipose tissue were obtained for histopathological, metabolomic, and protein expression analyses.

RESULTS

HF-HSD (but not HFD) was associated with NASH and increased oxidative stress. These animals presented an inhibition of hepatic autophagy and alterations in AMP-activated protein kinase/mammalian target of rapamycin activity. We also observed that the ability of metabolic adaptation was adversely affected by the increase of damaged mitochondria. NASH development was associated with changes in adipose tissue dynamics and increased amounts of saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids in visceral adipose tissue.

CONCLUSION

HF-HSD led to a metabolic blockage and impaired hepatic mitochondria turnover. In addition, the continuous accumulation of fatty acids produced adipose tissue dysfunction and hepatic fat accumulation that favored the progression to NASH.

The Crosstalk Between Tumor-Associated Macrophages (TAMs) and Tumor Cells and the Corresponding Targeted Therapy

Tumor microenvironment (TME) is composed of tumor cells and surrounding non-tumor stromal cells, mainly including tumor associated macrophages (TAMs), endothelial cells, and carcinoma-associated fibroblasts (CAFs). The TAMs are the major components of non-tumor stromal cells, and play an important role in promoting the occurrence and development of tumors. Macrophages originate from bone marrow hematopoietic stem cells and embryonic yolk sacs. There is close crosstalk between TAMs and tumor cells. With the occurrence of tumors, tumor cells secrete various chemokines to recruit monocytes to infiltrate tumor tissues and further promote their M2-type polarization. Importantly, M2-like TAMs can in turn accelerate tumor growth, promote tumor cell invasion and metastasis, and inhibit immune killing to promote tumor progression. Therefore, targeting TAMs in tumor tissues has become one of the principal strategies in current tumor immunotherapy. Current treatment strategies focus on reducing macrophage infiltration in tumor tissues and reprogramming TAMs to M1-like to kill tumors. Although these treatments have had some success, their effects are still limited. This paper mainly summarized the recruitment and polarization of macrophages by tumors, the support of TAMs for the growth of tumors, and the research progress of TAMs targeting tumors, to provide new treatment strategies for tumor immunotherapy.

Photoacoustic Imaging for Assessing Tissue Oxygenation Changes in Rat Hepatic Fibrosis

Chronic liver inflammation progressively evokes fibrosis and cirrhosis resulting in compromised liver function, and often leading to cancer. Early diagnosis and staging of fibrosis is crucial because the five-year survival rate of early-stage liver cancer is high. This study investigates the progression of hepatic fibrosis induced in rats following ingestion of diethylnitrosamine (DEN). Changes in oxygen saturation and hemoglobin concentration resulting from chronic inflammation were assayed longitudinally during DEN ingestion by photoacoustic imaging (PAI). Accompanying liver tissue changes were monitored simultaneously by B-mode sonographic imaging. Oxygen saturation and hemoglobin levels in the liver increased over 5 weeks and peaked at 10 weeks before decreasing at 13 weeks of DEN ingestion. The oxygenation changes were accompanied by an increase in hepatic echogenicity and coarseness in the ultrasound image. Histology at 13 weeks confirmed the development of severe fibrosis and cirrhosis. The observed increase in PA signal representing enhanced blood oxygenation is likely an inflammatory physiological response to the dietary DEN insult that increases blood flow by the development of neovasculature to supply oxygen to a fibrotic liver during the progression of hepatic fibrosis. Assessment of oxygenation by PAI may play an important role in the future assessment of hepatic fibrosis.

Translational Considerations to Improve Response and Overcome Therapy Resistance in Immunotherapy for Hepatocellular Carcinoma

Over the last decade, progress in systemic therapies significantly improved the outcome of primary liver cancer. More recently, precision oncological and immunotherapeutic approaches became the focus of intense scientific and clinical research. Herein, preclinical studies showed promising results with high response rates and improvement of overall survival. However, results of phase III clinical trials revealed that only a subfraction of hepatocellular carcinoma (HCC) patients respond to therapy and display only moderate objective response rates. Further, predictive molecular characteristics are largely missing. In consequence, suitable trial design has emerged as a crucial factor for the success of a novel compound. In addition, increasing knowledge from translational studies indicate the importance of targeting the tumor immune environment to overcome resistance to immunotherapy. Thus, combination of different immunotherapies with other treatment modalities including antibodies, tyrosine kinase inhibitors, or local therapies is highly promising. However, the mechanisms of failure to respond to immunotherapy in liver cancer are still not fully understood and the modulation of the immune system and cellular tumor composition is particularly relevant in this context. Altogether, it is increasingly clear that tailoring of immunotherapy and individualized approaches are required to improve efficacy and patient outcome in liver cancer. This review provides an overview of the current knowledge as well as translational considerations to overcome therapy resistance in immunotherapy of primary liver cancer.

A murine cellular model of necroinflammation displays RAGE-dependent cytokine induction that connects to hepatoma cell injury

Unresolved inflammation maintained by release of danger‐associated molecular patterns, particularly high‐mobility group box‐1 (HMGB1), is crucial for hepatocellular carcinoma (HCC) pathogenesis. To further characterize interactions between leucocytes and necrotic cancerous tissue, a cellular model of necroinflammation was studied in which murine Raw 264.7 macrophages or primary splenocytes were exposed to necrotic lysates (N‐lys) of murine hepatoma cells or primary hepatocytes. In comparison to those derived from primary hepatocytes, N‐lys from hepatoma cells were highly active—inducing in macrophages efficient expression of inflammatory cytokines like C‐X‐C motif ligand‐2 , tumor necrosis factor‐α, interleukin (IL)‐6 and IL‐23‐p19. This activity associated with higher levels of HMGB1 in hepatoma cells and was curbed by pharmacological blockage of the receptor for advanced glycation end product (RAGE)/HMGB1 axis or the mitogen‐activated protein kinases ERK1/2 pathway. Analysis of murine splenocytes furthermore demonstrated that N‐lys did not comprise of functionally relevant amounts of TLR4 agonists. Finally, N‐lys derived from hepatoma cells supported inflammatory splenic Th17 and Th1 polarization as detected by IL‐17, IL‐22 or interferon‐γ production. Altogether, a straightforward applicable model was established which allows for biochemical characterization of immunoregulation by HCC necrosis in cell culture. Data presented indicate a remarkably inflammatory capacity of necrotic hepatoma cells that, at least partly, depends on the RAGE/HMGB1 axis and may shape immunological properties of the HCC microenvironment.

T Cell Dysfunction and Exhaustion in Cancer

Tumor immunotherapy is a promising therapeutic strategy for patients with advanced cancers. T cells are key mediators of antitumor function that specifically recognize and react to tumor-expressing antigens and have proven critical for cancer immunotherapy. However, T cells are not as effective against cancer as expected. This is partly because T cells enter a dysfunctional or exhausted state, which is characterized by sustained expression of inhibitory receptors and a transcriptional state distinct from that of functional effector or memory T cells. T cell dysfunction induces the out of control of tumors. Recently, T cell dysfunction has been investigated in many experimental and clinical settings. The molecular definition of T cell dysfunction and the underlying causes of the T cell dysfunction has been advanced regardless of the fact that the pathways involved are not well elucidated, which proposing promising therapeutic opportunities in clinic. In this review, we will discuss the recent advances in the molecular mechanisms that affect TME and induce T cell dysfunction, and the development of promising immunotherapies to counteract the mechanisms of tumor-induced T cell dysfunction. Better understanding these underlying mechanisms may lead to new strategies to improve the clinical outcome of patients with cancer.

Ultrasound-mediated delivery of miRNA-122 and anti-miRNA-21 therapeutically immunomodulates murine hepatocellular carcinoma in vivo

Hepatocellular carcinoma (HCC) is the most common cause of cancer-related mortality, and patients with HCC show poor response to currently available treatments, which demands new therapies. We recently developed a synthetic microRNA-based molecularly targeted therapy for improving HCC response to chemotherapy by eliminating drug resistance. We used ultrasound-targeted microbubble destruction (UTMD) to locally deliver microRNA-loaded nanoparticles to HCC. Since the immune microenvironment plays a crucial role in HCC disease development and response to treatment, and UTMD and microRNAs have the potential to interfere with the immune system, in this study we analyzed the immunomodulatory effects of UTMD and miRNAs in HCC. We used an immunocompetent syngeneic HCC mouse model for the study. We conducted cytokine profiling in tumor, lymph nodes, and serum of animals within the first 24 h of treatment to analyze changes in the level of pro- and antitumoral cytokines. The results showed: (1) Hepa1-6 syngeneic tumors expressed HCC-related cytokines, (2) UTMD-microRNA combination therapy triggered transient cytokine storms, and (3) delivery of microRNA-122 and anti-microRNA-21 affected the immune microenvironment by decreasing the level of GM-CSF in tumors while modulating protumoral IL-1α, IL-1β, IL-5, IL-6 and IL-17 and antitumoral IL-2 and IL-12 in tumor-proximal lymph nodes, and increasing IL-2 in the serum of tumor-bearing mice. Local delivery of targeted therapy by UTMD significantly reduced the concentration of IL-12 and IL-17 in lymph nodes of treated and contralateral tumors suggesting a systemic response. CONCLUSION: UTMD-mediated delivery of microRNA-122 and anti-microRNA-21 modulated the immune microenvironment of Hepa1-6 tumors at the level of cytokine expressions. Exploiting antitumoral immune effects could enhance the therapeutic efficacy of the proposed combination therapy for HCC.

Plant seed protease inhibitors differentially affect innate immunity in a tumor microenvironment to control hepatocarcinoma

Identifying tolerance responses to ingested foodstuff over life is essential for understanding dysfunction in metabolic diseases. This study presents a comparative structural and functional analysis of serine-type protease inhibitors (STPIs) from Chenopodium quinoa, Salvia hispanica L., Avena sativa and Triticum durum. It also evaluates their influence on an in vivo hepatocarcinoma (HCC) model. STPIs are found in all samples with significant differences in protease inhibitory capacity: C. quinoa = S. hispanica < A. sativa = T. durum. STPIs in C. quinoa and S. hispanica appear as heterologous complexes, while those in A. sativa are present as homologous complexes. T. durum provides different subunits with STPI capacity. HPLC-RP-ESI analyses revealed homology between STPIs in the different samples and the partial resistance of those to simulated gastrointestinal digestion. In vivo, STPIs from S. hispanica showed the most positive effects, increasing F4/80+ cells normalizing the expression (mRNA) of CD36 and the innate immune 'Toll-like' receptor (TLR)-4. Only STPIs from C. quinoa and S. hispanica did not impair the production of inflammatory mediators (granulocyte-monocyte colony stimulating factor, stem cell factor and TNFα), contributing to maintaining the polarization of the antitumoral M1 macrophage phenotype. These structural and functional features of STPIs from C. quinoa and S. hispanica can be used to control HCC aggressiveness.

Hydrocortisone Suppresses Early Paraneoplastic Inflammation And Angiogenesis To Attenuate Early Hepatocellular Carcinoma Progression In Rats

Background

Inflammation is implicated in both hepatic cirrhosis development and hepatocellular carcinogenesis, and treatment with long-acting glucocorticoid dexamethasone prevented liver carcinogenesis in mice. However, it is unclear whether glucocorticoids have anti-inflammatory effect on hepatocellular carcinoma (HCC) and if short-acting glucocorticoids (with fewer adverse effects) inhibit paraneoplastic inflammation and HCC progression.

Methods

To investigate whether different types of anti-inflammatory agents attenuate HCC progression, the current study compared effects of treatments with hydrocortisone (a short-acting glucocorticoid) or aspirin on HCC progression. HCC was induced in diethylnitrosamine-treated rats which were randomly divided into 4 groups (n=8), respectively receiving orally once daily vehicle, glucuronolactone, glucuronolactone+hydrocortisone, and glucuronolactone+aspirin. Diethylnitrosamine (DEN) was given to rats in drinking water (100mg/L) to induce HCC. At weeks 12 and 16 post-induction, effects were compared on HCC nodule formation, microvessel density, and macrophage infiltration, and levels of paraneoplastic protein expression of tumor necrosis factor (TNF)-α, p38 mitogen-activated protein kinase (p38), phosphorylated p38 (p-p38), nuclear factor (NF)-κB, interleukin (IL)-10, hepatocyte growth factor (HGF), transforming growth factor (TGF)-β1 and vascular endothelial growth factor (VEGF).

Results

Compared to the model and glucuronolactone alone groups, HCC nodule number and microvessel density in the glucuronolactone+hydrocortisone group were significantly lower at week 12. At week 12 but not week 16, significantly lower levels of macrophages, TNF-α, p-p38, NF-κB, IL-10, HGF, TGF-β1 and VEGF were observed in the paraneoplastic tissue of the glucuronolactone+hydrocortisone group when compared with the control and glucuronolactone groups.

Conclusion

The results suggest that hydrocortisone treatment reduces macrophage polarization, expression of inflammatory and anti-inflammatory cytokines, and angiogenesis in paraneoplastic tissue, and attenuates early HCC progression. Although hydrocortisone did not have attenuation effect on advanced solid tumor, the current study shows the potential benefits and supports potential clinical use of hydrocortisone in attenuating early progression of HCC, which is through suppressing paraneoplastic inflammation and angiogenesis.

Mitochondrial Dysfunction in the Transition from NASH to HCC

The liver constantly adapts to meet energy requirements of the whole body. Despite its remarkable adaptative capacity, prolonged exposure of liver cells to harmful environmental cues (such as diets rich in fat, sugar, and cholesterol) results in the development of chronic liver diseases (including non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH)) that can progress to hepatocellular carcinoma (HCC). The pathogenesis of these diseases is extremely complex, multifactorial, and poorly understood. Emerging evidence suggests that mitochondrial dysfunction or maladaptation contributes to detrimental effects on hepatocyte bioenergetics, reactive oxygen species (ROS) homeostasis, endoplasmic reticulum (ER) stress, inflammation, and cell death leading to NASH and HCC. The present review highlights the potential contribution of altered mitochondria function to NASH-related HCC and discusses how agents targeting this organelle could provide interesting treatment strategies for these diseases.

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.

From bench to bed: the tumor immune microenvironment and current immunotherapeutic strategies for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) ranks the most common primary liver malignancy and the third leading cause of tumor-related mortality worldwide. Unfortunately, despite advances in HCC treatment, less than 40% of HCC patients are eligible for potentially curative therapies. Recently, cancer immunotherapy has emerged as one of the most promising approaches for cancer treatment. It has been proven therapeutically effective in many types of solid tumors, such as non-small cell lung cancer and melanoma. As an inflammation-associated tumor, it's well-evidenced that the immunosuppressive microenvironment of HCC can promote immune tolerance and evasion by various mechanisms. Triggering more vigorous HCC-specific immune response represents a novel strategy for its management. Pre-clinical and clinical investigations have revealed that various immunotherapies might extend current options for needed HCC treatment. In this review, we provide the recent progress on HCC immunology from both basic and clinical perspectives, and discuss potential advances and challenges of immunotherapy in HCC.

Tissue Immune Cells Fuel Obesity-Associated Inflammation in Adipose Tissue and Beyond

Obesity-associated inflammation stems from a combination of cell-intrinsic changes of individual immune cell subsets and the dynamic crosstalk amongst a broad array of immune cells. Although much of the focus of immune cell contributions to metabolic disease has focused on adipose tissue-associated cells, these potent sources of inflammation inhabit other metabolic regulatory tissues, including liver and gut, and recirculate to promote systemic inflammation and thus obesity comorbidities. Tissue-associated immune cells, especially T cell subpopulations, have become a hotspot of inquiry based on their contributions to obesity, type 2 diabetes, non-alcoholic fatty liver diseases and certain types of cancers. The cell-cell interactions that take place under the stress of obesity are mediated by intracellular contact and cytokine production, and constitute a complicated network that drives the phenotypic alterations of immune cells and perpetuates a feed-forward loop of metabolic decline. Herein we discuss immune cell functions in various tissues and obesity-associated cancers from the viewpoint of inflammation. We also emphasize recent advances in the understanding of crosstalk amongst immune cell subsets under obese conditions, and suggest future directions for focused investigations with clinical relevance.

Generation of monocyte-derived tumor-associated macrophages using tumor-conditioned media provides a novel method to study tumor-associated macrophages in vitro

Background

Tumor-associated macrophages (TAM) are expanded and exhibit tumor-promoting properties within the tumor microenvironment. Current methods to study TAM have not been replicated across cancer types and often do not include exogenous growth factors from the tumor, a key factor in TAM differentiation in vivo.

Methods

In this study, an in vitro method to generate monocyte- derived TAM using tumor- conditioned media (TCM) and a cytokine cocktail containing IL-4, IL-10, and M-CSF was utilized to study the phenotype, morphology, and function of TAM across multiple cancer types. TCM was generated from two breast cancer cell lines and an Epstein-Barr virus-positive lymphoma cell line. The properties of in vitro generated TAM were compared to in vitro generated M1 and M2- like macrophages and TAM isolated from patients with cancer.

Results

TAM generated in this fashion displayed an increase in CD163/CD206 co-expression compared to M2- like macrophages (87 and 36%, respectively). TAM generated in vitro exhibited increased transcript levels of the functional markers IL-6, IL-10, CCL2, c-Myc, iNOS, and arginase compared to in vitro generated M2-like macrophages. Functionally, in vitro generated TAM inhibited the proliferation of T cells (47% decrease from M1-like macrophages) and the production of IFN-γ by natural killer cells was inhibited (44%) when co-cultured with TAM. Furthermore, in vitro generated TAM secreted soluble factors that promote the growth and survival of tumor cells.

Conclusions

Limited access to patient TAM highlights the need for methods to generate TAM in vitro. Our data confirm that monocyte-derived TAM can be generated reliably using TCM plus the cytokine cocktail of IL-4, IL-10, and M-CSF. Given the ability of TAM to inhibit immune cell function, continued study of methods to deplete or deactivate TAM in the setting of cancer are warranted.

Electronic supplementary material

The online version of this article (10.1186/s40425-019-0622-0) contains supplementary material, which is available to authorized users.

Iron alters macrophage polarization status and leads to steatohepatitis and fibrogenesis

We have previously demonstrated that iron overload in hepatic reticuloendothelial system cells (RES) is associated with severe nonalcoholic steatohepatitis (NASH) and advanced fibrosis in patients with nonalcoholic fatty liver disease (NAFLD). Recruited myeloid-derived macrophages have gained a pivotal position as drivers of NASH progression and fibrosis. In this study, we used bone marrow-derived macrophages (BMDM) from C57Bl6 mice as surrogates for recruited macrophages and examined the effect of iron on macrophage polarization. Treatment with iron (ferric ammonium citrate, FAC) led to increased expression levels of M1 markers: CCL2, CD14, iNOS, IL-1β, IL-6, and TNF-α; it also increased protein levels of CD68, TNF-α, IL-1β, and IL-6 by flow cytometry. This effect could be reversed by desferrioxamine, an iron chelator. Furthermore, iron loading of macrophages in the presence of IL-4 led to the down-regulation of M2 markers: arginase-1, Mgl-1, and M2-specific transcriptional regulator, KLF4. Iron loading of macrophages with IL-4 also resulted in reduced phosphorylation of STAT6, another transcriptional regulator of M2 activation. Dietary iron overload of C57Bl6 mice led to hepatic macrophage M1 activation. Iron overload also stimulated hepatic fibrogenesis. Histologic analysis revealed that iron overload resulted in steatohepatitis. Furthermore, NAFLD patients with hepatic RES iron deposition had increased hepatic gene expression levels of M1 markers, IL-6, IL-1β, and CD40 and reduced gene expression of an M2 marker, TGM2, relative to patients with hepatocellular iron deposition pattern. We conclude that iron disrupts the balance between M1/M2 macrophage polarization and leads to macrophage-driven inflammation and fibrogenesis in NAFLD.