The XOR-IDH3α axis controls macrophage polarization in hepatocellular carcinoma

Calceolarioside B targets MMP12 in the tumor microenvironment to inhibit M2 macrophage polarization and suppress hepatocellular carcinoma progression

BACKGROUND

Tumor-associated macrophages (TAMs) are crucial in hepatocellular carcinoma (HCC) progression and prognosis, making them promising immunotherapy targets. In traditional Chinese medicine (TCM), qi stagnation and blood stasis are linked to the HCC tumor microenvironment (TME), but few studies explore the effects of related TCM herbs on the TME. Calceolarioside B, a key phenylethanoid glycoside in Akebiae Fructus, has not been well studied for its pharmacological activities or molecular targets, and its role in HCC remains unclear.

PURPOSE

This study aimed to investigate the effects of Calceolarioside B on TAMs in HCC and clarify its potential targets and regulatory mechanisms.

METHODS

Murine intrahepatic transplantation HCC models and macrophage-HCC cell co-culture systems were used to investigate the effects of Calceolarioside B on M2-like TAMs polarization and infiltration, and tumor growth. Cellular thermal shift assay, small molecular pull-down assay and surface plasmon resonance were utilized to identify the potential targets regulating M2-like TAMs. Single-cell RNA sequencing and TCGA dataset analyses clarified the differential expression, prognosis, and TAMs association of the potential targets in HCC.

RESULTS

Calceolarioside B reduces M2-like TAMs polarization and infiltration in the TME by binding to and inhibiting matrix metallopeptidase-12 (MMP12) form both macrophages and HCC cells, thereby preventing immunosuppressive effects. Public database analysis revealed that MMP12 overexpression promoted macrophage infiltration, with MMP12+ macrophages preferentially aggregating in primary and metastatic HCC tumors.

CONCLUSION

Calceolarioside B is identified as a novel MMP12 inhibitor modulating TAMs in the TME, offering a potential TAM-targeting strategy for HCC therapy.

NLRP4 unlocks an NK/macrophages-centered ecosystem to suppress non-small cell lung cancer

BACKGROUND

Tumor immune evasion extends beyond T cells, affecting innate immune elements like natural killer cells (NK) and macrophages within the tumor-immune microenvironment (TIME). Nevertheless, translational strategies to trigger collaboration of NK cells and macrophages to initiate sufficient anti-tumor cytoxicity remain scarce and are urgently needed.

METHODS

In this study, TCGA datasets was used to confirm the prognosis value of the expression level of NLR family pyrin domain containing 4 (NLRP4) in NSCLC and the tumor tissues microarray was used to further check its clinical-relevance at protein-level. Subsequently, a tumor cell line with stable NLRP4 overexpression was established and subcutaneous tumor models in C57BL/6J mice were used to validate the anti-tumor characteristics of NLRP4. After analyzing the tumor microenvironment using flow cytometry and multiplex immunofluorescence, we further validated our findings through co-culture transwell assays and TCGA analysis. Utilizing bulk-RNA sequencing, proteomics, and mass spectrometry of mouse tumor tissues, we innovatively identified the downstream pathways of NLRP4 and verified them through co-immunoprecipitation (co-IP) and Western blot (WB) experiments.

RESULTS

NLRP4 could trigger a distinct anti-tumor ecosystem organized by TIGIT+TNFA+ NK and iNOS+ M1 in lung cancer, discovered in TCGA analysis and verified in murine model. NLRP4-eco exerted tumor-suppression capacity through chemokine reprogramming including CCL5 and CXCL2. Meanwhile, the cytoxicity of NK could be facilitated by iNOS+M1. Mechanistically, NLRP4 stimulated PI3K/Akt-NF-kB axis through suppression of the activity of PP2A. Besides, knockdown of CCL5 and blockade of CXCL2-CXCR2 axis abolished chemotaxis of TIGIT+TNFA+ NK and iNOS+ M1 respectively, as well as for LB-100, a PP2A inhibitor.

CONCLUSION

Altogether, we delineated NLRP4's unexplored facets and discovered an NLRP4-driven anti-tumor ecosystem composed of TIGIT+TNFA+ NK and iNOS+ M1. Finally, targeting PP2A by its inhibitor successfully mimicked the anti-tumor capacity of the overexpression of NLRP4.

TCR-T cell therapy for solid tumors: challenges and emerging solutions

With the use of T cell receptor T cells (TCR-T cells) and chimeric antigen receptor T cells (CAR-T cells), T-cell immunotherapy for cancer has advanced significantly in recent years. CAR-T cell therapy has demonstrated extraordinary success when used to treat hematologic malignancies. Nevertheless, there are several barriers that prevent this achievement from being applied to solid tumors, such as challenges with tumor targeting and inadequate transit and adaption of genetically modified T-cells, especially in unfavorable tumor microenvironments The deficiencies of CAR-T cell therapy in the treatment of solid tumors are compensated for by TCR-T cells, which have a stronger homing ability to initiate intracellular commands, 90% of the proteins can be used as developmental targets, and they can recognize target antigens more broadly. As a result, TCR-T cells may be more effective in treating solid tumors. In this review, we discussed the structure of TCR-T and have outlined the drawbacks of TCR-T in cancer therapy, and suggested potential remedies. This review is crucial in understanding the current state and future potential of TCR-T cell therapy. We emphasize how important it is to use combinatorial approaches, combining new combinations of various emerging strategies with over-the-counter therapies designed for TCR-T, to increase the anti-tumor efficacy of TCR-T inside the TME and maximize treatment safety, especially when it comes to solid tumor immunotherapies.

Integrated multiomics analysis highlights the immunosuppressive role of granulin precursor positive macrophages in hepatocellular carcinoma

It has been reported that tumor-associated macrophages (TAMs) play a complicated role in cancer occurrence and development, immune escape, and immune checkpoint blockade (ICB) resistance. However, the role of granulin precursor (GRN) highly expressed macrophages (hereafter refer to GRN+ macrophages) in hepatocellular carcinoma (HCC) remains poorly understood. Herein, we systematically integrated multiomics analysis of human tumor tissues to illustrate the functional role of GRN+ macrophages in HCC. GRN is selectively expressed by TAMs in different type of cancers including HCC, and was significantly associated with poor prognosis in several type of cancer. GRN was closely correlated with infiltration levels of most immune cells, especially the M2 macrophage cells in various cancers. In particular, both mRNA and protein expression level of GRN was significantly upregulated in HCC. Compared with tumor tissue, GRN was more significantly expressed in the stroma area between HCC tissues and adjacent non-tumor tissues. High expression of GRN was significantly correlated with M2-polarization of macrophages and T-cell exhaustion in HCC. GRN+ macrophages communicated with intratumoral immune cells, especially CD8+ T cells. Functionally, GRN+ macrophages contacted with CD8+ T cells, which inducing T-cell exhaustion. Our study offers a comprehensive understanding of the clinical relevance and immunological role of GRN+ macrophages in HCC, indicating its potential role as a promising target for immunotherapeutic strategies.

The protein circPETH-147aa regulates metabolic reprogramming in hepatocellular carcinoma cells to remodel immunosuppressive microenvironment

Metabolic reprogramming fuels cancer cell metastasis and remodels the immunosuppressive tumor microenvironment (TME). We report here that circPETH, a circular RNA (circRNA) transported via extracellular vesicles (EVs) from tumor-associated macrophages (TAMs) to hepatocellular carcinoma (HCC) cells, facilitates glycolysis and metastasis in recipient HCC cells. Mechanistically, circPETH-147aa, encoded by circPETH in an m6A-driven manner, promotes PKM2-catalyzed ALDOA-S36 phosphorylation via the MEG pocket. Furthermore, circPETH-147aa impairs anti-HCC immunity by increasing HuR-dependent SLC43A2 mRNA stability and driving methionine and leucine deficiency in cytotoxic CD8+ T cells. Importantly, through virtual and experimental screening, we find that a small molecule, Norathyriol, is an effective inhibitor that targets the MEG pocket on the circPETH-147aa surface. Norathyriol reverses circPETH-147aa-facilitated acquisition of metabolic and metastatic phenotypes by HCC cells, increases anti-PD1 efficacy, and enhances cytotoxic CD8+ T-cell function. Here we show that Norathyriol is a promising anti-HCC agent that contributes to attenuating the resistance of advanced HCC to immune checkpoint blocker (ICB) therapies.

RBM25 is required to restrain inflammation via ACLY RNA splicing-dependent metabolism rewiring

Spliceosome dysfunction and aberrant RNA splicing underline unresolved inflammation and immunopathogenesis. Here, we revealed the misregulation of mRNA splicing via the spliceosome in the pathogenesis of rheumatoid arthritis (RA). Among them, decreased expression of RNA binding motif protein 25 (RBM25) was identified as a major pathogenic factor in RA patients and experimental arthritis mice through increased proinflammatory mediator production and increased hyperinflammation in macrophages. Multiomics analyses of macrophages from RBM25-deficient mice revealed that the transcriptional enhancement of proinflammatory genes (including Il1b, Il6, and Cxcl10) was coupled with histone 3 lysine 9 acetylation (H3K9ac) and H3K27ac modifications as well as hypoxia inducible factor-1α (HIF-1α) activity. Furthermore, RBM25 directly bound to and mediated the 14th exon skipping of ATP citrate lyase (Acly) pre-mRNA, resulting in two distinct Acly isoforms, Acly Long (Acly L) and Acly Short (Acly S). In proinflammatory macrophages, Acly L was subjected to protein lactylation on lysine 918/995, whereas Acly S did not, which influenced its affinity for metabolic substrates and subsequent metabolic activity. RBM25 deficiency overwhelmingly increased the expression of the Acly S isoform, enhancing glycolysis and acetyl-CoA production for epigenetic remodeling, macrophage overactivation and tissue inflammatory injury. Finally, macrophage-specific deletion of RBM25 led to inflammaging, including spontaneous arthritis in various joints of mice and inflammation in multiple organs, which could be relieved by pharmacological inhibition of Acly. Overall, targeting the RBM25-Acly splicing axis represents a potential strategy for modulating macrophage responses in autoimmune arthritis and aging-associated inflammation.

Tumor‑associated macrophages activated in the tumor environment of hepatocellular carcinoma: Characterization and treatment (Review)

Hepatocellular carcinoma (HCC) tissue is rich in dendritic cells, T cells, B cells, macrophages, natural killer cells and cellular stroma. Together they form the tumor microenvironment (TME), which is also rich in numerous cytokines. Tumor‑associated macrophages (TAMs) are involved in the regulation of tumor development. TAMs in HCC receive stimuli in different directions, polarize in different directions and release different cytokines to regulate the development of HCC. TAMs are mostly divided into two cell phenotypes: M1 and M2. M1 TAMs secrete pro‑inflammatory mediators, and M2 TAMs secrete a variety of anti‑inflammatory and pro‑tumorigenic substances. The TAM polarization in HCC tumors is M2. Both direct and indirect methods for TAMs to regulate the development of HCC are discussed. TAMs indirectly support HCC development by promoting peripheral angiogenesis and regulating the immune microenvironment of the TME. In terms of the direct regulation between TAMs and HCC cells, the present review mainly focuses on the molecular mechanism. TAMs are involved in both the proliferation and apoptosis of HCC cells to regulate the quantitative changes of HCC, and stimulate the related invasive migratory ability and cell stemness of HCC cells. The present review aims to identify immunotherapeutic options based on the mechanisms of TAMs in the TME of HCC.

CD8+ T cell exhaustion and its regulatory mechanisms in the tumor microenvironment: key to the success of immunotherapy

A steady dysfunctional state caused by chronic antigen stimulation in the tumor microenvironment (TME) is known as CD8+ T cell exhaustion. Exhausted-like CD8+ T cells (CD8+ Tex) displayed decreased effector and proliferative capabilities, elevated co-inhibitory receptor generation, decreased cytotoxicity, and changes in metabolism and transcription. TME induces T cell exhaustion through long-term antigen stimulation, upregulation of immune checkpoints, recruitment of immunosuppressive cells, and secretion of immunosuppressive cytokines. CD8+ Tex may be both the reflection of cancer progression and the reason for poor cancer control. The successful outcome of the current cancer immunotherapies, which include immune checkpoint blockade and adoptive cell treatment, depends on CD8+ Tex. In this review, we are interested in the intercellular signaling network of immune cells interacting with CD8+ Tex. These findings provide a unique and detailed perspective, which is helpful in changing this completely unpopular state of hypofunction and intensifying the effect of immunotherapy.

Role of ACSL4 in modulating farnesoid X receptor expression and M2 macrophage polarization in HBV-induced hepatocellular carcinoma

The intricate relationship between bile acid (BA) metabolism, M2 macrophage polarization, and hepatitis B virus-hepatocellular carcinoma (HBV-HCC) necessitates a thorough investigation of ACSL4's (acyl-CoA synthetase long-chain family member 4) role. This study combines advanced bioinformatics and experimental methods to elucidate ACSL4's significance in HBV-HCC development. Using bioinformatics, we identified differentially expressed genes in HBV-HCC. STRING and gene set enrichment analysis analyses were employed to pinpoint critical genes and pathways. Immunoinfiltration analysis, along with in vitro and in vivo experiments, assessed M2 macrophage polarization and related factors. ACSL4 emerged as a pivotal gene influencing HBV-HCC. In HBV-HCC liver tissues, ACSL4 exhibited upregulation, along with increased levels of M2 macrophage markers and BA. Silencing ACSL4 led to heightened farnesoid X receptor (FXR) expression, reduced BA levels, and hindered M2 macrophage polarization, thereby improving HBV-HCC conditions. This study underscores ACSL4's significant role in HBV-HCC progression. ACSL4 modulates BA-mediated M2 macrophage polarization and FXR expression, shedding light on potential therapeutic targets and novel insights into HBV-HCC pathogenesis.

Role of tumor-associated macrophages in hepatocellular carcinoma: impact, mechanism, and therapy

Hepatocellular carcinoma (HCC) is a highly frequent malignancy worldwide. The occurrence and progression of HCC is a complex process closely related to the polarization of tumor-associated macrophages (TAMs) in the tumor microenvironment (TME). The polarization of TAMs is affected by a variety of signaling pathways and surrounding cells. Evidence has shown that TAMs play a crucial role in HCC, through its interaction with other immune cells in the TME. This review summarizes the origin and phenotypic polarization of TAMs, their potential impacts on HCC, and their mechanisms and potential targets for HCC immunotherapy.

Immunotherapies Targeting Tumor-Associated Macrophages (TAMs) in Cancer

Tumor-associated macrophages (TAMs) are one of the most plentiful immune compositions in the tumor microenvironment, which are further divided into anti-tumor M1 subtype and pro-tumor M2 subtype. Recent findings found that TAMs play a vital function in the regulation and progression of tumorigenesis. Moreover, TAMs promote tumor vascularization, and support the survival of tumor cells, causing an impact on tumor growth and patient prognosis. Numerous studies show that reducing the density of TAMs, or modulating the polarization of TAMs, can inhibit tumor growth, indicating that TAMs are a promising target for tumor immunotherapy. Recently, clinical trials have found that treatments targeting TAMs have achieved encouraging results, and the U.S. Food and Drug Administration has approved a number of drugs for use in cancer treatment. In this review, we summarize the origin, polarization, and function of TAMs, and emphasize the therapeutic strategies targeting TAMs in cancer treatment in clinical studies and scientific research, which demonstrate a broad prospect of TAMs-targeted therapies in tumor immunotherapy.

The roles of cancer stem cell-derived secretory factors in shaping the immunosuppressive tumor microenvironment in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most prevalent malignancies worldwide and has a poor prognosis. Although immune checkpoint inhibitors have entered a new era of HCC treatment, their response rates are modest, which can be attributed to the immunosuppressive tumor microenvironment within HCC tumors. Accumulating evidence has shown that tumor growth is fueled by cancer stem cells (CSCs), which contribute to therapeutic resistance to the above treatments. Given that CSCs can regulate cellular and physical factors within the tumor niche by secreting various soluble factors in a paracrine manner, there have been increasing efforts toward understanding the roles of CSC-derived secretory factors in creating an immunosuppressive tumor microenvironment. In this review, we provide an update on how these secretory factors, including growth factors, cytokines, chemokines, and exosomes, contribute to the immunosuppressive TME, which leads to immune resistance. In addition, we present current therapeutic strategies targeting CSC-derived secretory factors and describe future perspectives. In summary, a better understanding of CSC biology in the TME provides a rational therapeutic basis for combination therapy with ICIs for effective HCC treatment.

Antitumor immunostimulatory activity of the traditional Chinese medicine polysaccharide on hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a prevalent malignancy, often associated with compromised immune function in affected patients. This can be attributed to the secretion of specific factors by liver cancer cells, which hinder the immune response and lead to a state of immune suppression. Polysaccharides derived from traditional Chinese medicine (TCM) are valuable constituents known for their immunomodulatory properties. This review aims to look into the immunomodulatory effects of TCM polysaccharides on HCC. The immunomodulatory effects of TCM polysaccharides are primarily manifested through the activation of effector T lymphocytes, dendritic cells, NK cells, and macrophages against hepatocellular carcinoma (HCC) both in vivo and in vitro settings. Furthermore, TCM polysaccharides have demonstrated remarkable adjuvant antitumor immunomodulatory effects on HCC in clinical settings. Therefore, the utilization of TCM polysaccharides holds promising potential for the development of novel therapeutic agents or adjuvants with advantageous immunomodulatory properties for HCC.