METTL3 drives NAFLD-related hepatocellular carcinoma and is a therapeutic target for boosting immunotherapy

The regulatory roles of RNA-binding proteins in the tumour immune microenvironment of gastrointestinal malignancies

The crosstalk between the tumour immune microenvironment (TIME) and tumour cells promote immune evasion and resistance to immunotherapy in gastrointestinal (GI) tumours. Post-transcriptional regulation of genes is pivotal to GI tumours progression, and RNA-binding proteins (RBPs) serve as key regulators via their RNA-binding domains. RBPs may exhibit either anti-tumour or pro-tumour functions by influencing the TIME through the modulation of mRNAs and non-coding RNAs expression, as well as post-transcriptional modifications, primarily N6-methyladenosine (m6A). Aberrant regulation of RBPs, such as HuR and YBX1, typically enhances tumour immune escape and impacts prognosis of GI tumour patients. Further, while targeting RBPs offers a promising strategy for improving immunotherapy in GI cancers, the mechanisms by which RBPs regulate the TIME in these tumours remain poorly understood, and the therapeutic application is still in its early stages. This review summarizes current advances in exploring the roles of RBPs in regulating genes expression and their effect on the TIME of GI tumours, then providing theoretical insights for RBP-targeted cancer therapies.

N6-methyladenosine-regulated exosome biogenesis orchestrates an immunosuppressive pre-metastatic niche in gastric cancer peritoneal metastasis

BACKGROUND

Gastric cancer peritoneal metastasis is clinically challenging, given the limited treatment options and poor prognosis. The molecular mechanisms that precede gastric cancer peritoneal metastasis, known as the pre-metastatic niche (PMN), and its relationship with N6-methyladenosine (m6A) modification remain unclear.

METHODS

We used 87 resected gastric cancer tissues and 4 public datasets to explore the association between methyltransferase-like 3 (METTL3) expression and gastric cancer peritoneal metastasis. Roles of m6A, exosomes, or macrophages in PMN formation were explored in immunocompetent mouse models through exosome treatments or macrophage modifications. Key genes and regulatory mechanisms were uncovered using mass spectrometry, RNA/miRNA sequencing, RNA-immunoprecipitation, dual-luciferase assays, and point mutations in the ras-related protein Rab-27A (RAB27A) in cells. Macrophage and T-cell functions were assessed using enzyme-linked immunosorbent assay, flow cytometry, and cytotoxicity assays.

RESULTS

METTL3 overexpression in gastric cancer cells enhanced RAB27A translation by methylating its mRNA A502 base, facilitated by its m6A "reader" YTH N6-methyladenosine RNA binding protein F1 (YTHDF1), and led to increased exosome biogenesis. The miRNA-17-92 cluster was enriched in METTL3-overexpressed cell-derived exosomes and targeted SRC kinase signaling inhibitor 1 (SRCIN1) to activate SRC proto-oncogene, non-receptor tyrosine kinase (SRC) signaling in peritoneal macrophages. Macrophage activation skewed cytokine production towards an immunosuppressive profile in the peritoneum, elevating the levels of interleukin (IL)-10 and tumor necrosis factor (TNF) and reducing the levels of IL-1 and IL-6. These cytokine shifts inhibited T cell proliferation and cytotoxic activities, which created an immunosuppressive PMN and led to peritoneal metastasis. The association between METTL3, macrophages, and peritoneal metastasis was verified in clinical samples.

CONCLUSIONS

Our study identified an intricate m6A-regulated mechanism of peritoneal PMN development that is mediated by exosome-promoted macrophages. These insights into gastric cancer peritoneal metastasis offer promising directions for translational research.

An exploration on the involvement of the methyltransferase like 3-m6A‑zinc finger MYM-type containing 1 axis in the progression of liver hepatocellular carcinoma

An existing study has underlined the involvement of Methyltransferase Like 3 (METTL3) and its mediated N6-methyladenosine (m6A) modification on zinc finger MYM-type containing 1 (ZMYM1) in cancers, and we aimed to explore their implication in liver hepatocellular carcinoma (LIHC). The levels of METTL3 and ZMYM1 in LIHC cells were gauged via qPCR. The involvement of METTL3 in LIHC progression was explored via assays in vitro and in vivo, and the mechanisms underlying the effects of METTL3 on LIHC were explored via m6A methylated RNA immunoprecipitation-qPCR (MeRIP-qPCR) and confocal immunofluorescence assays. METTL3, the m6A methyltransferase of interest, expressed relatively higher in LIHC. The promoting effects of METTL3 on LIHC progression were confirmed both in vitro and in vivo, and the relevant mechanisms maybe related to ZMYM1, a target of METTL3. Such effects of METTL3-m6A-ZMYM1 axis on the progression of LIHC were confirmed to be related to the inactivation of RAS/ERK/c-FOS pathway and the reduction in E-cadherin expression yet the elevation in N-cadherin and Vimentin expressions, therefore accelerating the metastasis in LIHC. Our study highlighted the possible involvement of METTL3-mediated m6A modification in LIHC and explored METTL3-m6A-ZMYM1 axis as a possible therapeutic target for the anti-metastatic strategy against LIHC.

A predictive model based on program cell death genes for prognosis and therapeutic response in early stage hepatocellular carcinoma

The principal cause of treatment ineffectiveness in hepatocellular carcinoma (HCC) patients stems from post-surgery stagnation and treatment resistance. A comprehensive predictive model for the progression and drug response of post-surgery HCC patients remains elusive. Various programmed cell death (PCD) patterns significantly influence tumor advancement, offering potential as prognostic and drug sensitivity indicators for postsurgery HCC. The analysis in this study utilized integrated data from 12 different types of PCD, multi-omics data from TCGA-HCC and other cohorts in the International Cancer Genome Consortium, as well as clinical information of HCC patients. A PCD score was calculated using a four-gene signature determined through cox regression analysis. Validation in independent datasets revealed that HCC patients with high PCD scores had poorer prognoses post-surgery. Furthermore, an unsupervised clustering model identified two distinct molecular subtypes of HCC with unique biological processes. A nomogram exhibiting high predictive accuracy was developed by integrating a PCD signature with clinical characteristics. The association between programmed cell death, immune checkpoints genes and key components of the tumor microenvironment. was established. Patients with HCC displaying elevated PCD levels demonstrated resistance to traditional adjuvant chemotherapy and immune checkpoints inhibitor therapies. Additionally, the oncogenic function of four PCD genes was identified in an inpatient cohort. A novel scoring methodology for PCD was devised through the examination of genes linked to diverse PCD subtypes, providing valuable insights into the prognosis and drug responsiveness of HCC patients. Early-stage HCC patients may potentially derive therapeutic benefits from immune therapy directed at programmed cell death.

Cholesterol effects on the tumor immune microenvironment: from fundamental concepts to mechanisms and implications

In many cancers, the tumor microenvironment is enriched with cholesterol due to increased biosynthesis and uptake by cancer cells, resulting in the accumulation of cholesterol, cholesterol esters, oxysterols and other metabolites with various functions. These molecules serve as structural components, energy sources and intracellular signaling mediators, while their toxic by-products are secreted to suppress anti-tumor immune activity and prevent lipid peroxidation that could induce cancer cell apoptosis. Immune cells in the tumor microenvironment also contribute to cholesterol dynamics. Tumor-associated macrophages (TAMs) release cholesterol to support tumor cell metabolism, while myeloid-derived suppressor cells (MDSCs) also release cholesterol and consume essential metabolites such as L-arginine, which impairs T-cell proliferation and activation. Elevated cholesterol in dendritic cells impairs migration and tumor antigen presentation and, in lymphocytes, favors the development of a regulatory T cells (Treg) phenotype and inhibits the release of antitumor cytokines, further weakening the immune response. These findings suggest that targeting cholesterol metabolism is a promising strategy for cancer treatment, improving the efficacy of immune checkpoint blockade (ICB) therapies. In this manuscript, the molecular mechanisms underlying the effects of cholesterol on the tumor immune landscape are reviewed and the potential of cholesterol-lowering drugs to enhance antitumor immune responses is explored.

METTL3, an Independent Adverse Prognostic Factor for AML, Promotes the Development of AML by Modulating the PGC-1α-MAPK Pathway and PGC-1α-Antioxidant System Axis

BACKGROUND

m6A represents a prevalent epigenetic modification of mammalian mRNAs. Studies have demonstrated that m6A RNA methylation-modifying enzymes play crucial roles in the onset and progression of AML. However, their clinical relevance remains undefined, and the mechanisms underlying their modulation of AML have yet to be elucidated.

RESULTS

The expression levels of the m6A RNA-modifying enzymes METTL3, METTL14, WTAP, FTO and ALKBH5 were elevated in AML patients. METTL3-positive AML is often accompanied by DNMT3A mutations and is also an independent poor prognostic factor for AML patients. Following METTL3 knockdown, we observed a decrease in the m6A level of the mitochondrial oxidative stress gene PGC-1α in K562 and MV4-11 cells. We analyzed the expression levels of PGC-1α and METTL3 mRNA in 105 patients with primary AML. The expression levels of PGC-1α and METTL3 mRNA were positively correlated. Similar to METTL3 knockdown, PGC-1α gene knockdown resulted in increased phosphorylation of the key signaling molecules P38, c-Jun and ERK1/2 in the MAPK signaling pathway, and decreased mRNA levels of SOD1, GPX1, catalase and UCP2 in the antioxidant system of K562 cells. Analysis of the TCGA and GSE13159 datasets, along with samples from West China Hospital, revealed that patients exhibiting high PGC-1α expression had a poor prognosis.

CONCLUSION

The m6A methylation-modifying enzyme METTL3 is an independent prognostic factor for poor prognosis in AML patients. PGC-1α is a downstream signaling molecule of METTL3, and METTL3 affects its expression by regulating the m6A level of PGC-1α. PGC-1α acts as an oncogene in AML by affecting the MAPK pathway and antioxidant system.

METTL3 and HERC4: Elevated Expression and Impact on Hepatocellular Carcinoma Progression

Background: Methyltransferase-like 3 (METTL3) and HECT and RLD domain containing E3 ubiquitin protein ligase 4 (HERC4) have been studied in the field of oncology; however, their roles and interaction in hepatocellular carcinoma (HCC) await elucidation. Methods: Initially, METTL3 and HERC4 expressions in normal and HCC samples were predicted employing the UALCAN database, and the targeting relationship between these two was explored via coimmunoprecipitation assay. Following the quantification on N6-methyladenosine (m6A) enrichment, the localization of METTL3 and HERC4 on HCC cells was visualized via immunofluorescence assay. The effects of METTL3 and HERC4 on HCC cells proliferation and migration were determined in vitro assays. METTL3 and HERC4 expressions were quantified via quantitative polymerase chain reaction, and those of metastasis-related proteins N-cadherin and vimentin were calculated with immunoblotting assay. Furthermore, the levels of angiogenic factors such as vascular endothelial growth factor and basic fibroblast growth factor were measured by enzyme-linked immunosorbent assay. Results: METTL3 and HERC4 expressed highly in HCC and their expressions were positively correlated with tumor grade. METTL3 overexpression enhanced the expression of HERC4 and promoted the proliferation and migration abilities of HCC cells. Specifically, METTL3 overexpression increased vimentin and N-cadherin expressions, while its silencing did conversely. Besides, HERC4 overexpression reversed the effects of METTL3 silencing on the proliferation and migration as well as the levels of angiogenic factors in HCC cells. Conclusion: This study reveals the upregulation of METTL3 and HERC4 expression in HCC and their role in HCC by enhancing the proliferation, migration, and angiogenesis potential of HCC cells.

Regulation and application of m6A modification in tumor immunity

The m6A modification is an RNA modification that impacts various processes of RNA molecules, including transcription, splicing, stability, and translation. Recently, researchers have discovered that the presence of m6A modification can influence the interaction between tumor cells and immune cells and also play a role in regulating the expression of immune response-related genes. Additionally, m6A modification is intricately involved in the regulation of tumor immune evasion and drug resistance. Specifically, certain tumor cells can manipulate the gene expression through m6A modification to evade immune system attacks. Therefore, it might be possible to enhance tumor immune surveillance and improve the effectiveness of immune-based therapies by manipulating m6A modification. This review systematically discusses the role of m6A modification in tumor immunity, specifically highlighting its regulation of immune cells and immune-related genes in tumor cells. Furthermore, we explore the potential of m6A modification inhibitors as anti-cancer therapies and the significance of m6A regulatory factors in predicting the efficacy of tumor immune therapy.

PCIF1 drives oesophageal squamous cell carcinoma progression via m6Am-mediated suppression of MTF2 translation

Oesophageal squamous cell carcinoma (OSCC) represents a highly aggressive malignancy with limited therapeutic options and poor prognosis. This study uncovers PCIF1 as a critical driver of OSCC progression via m6Am RNA modification, leading to translational repression of the tumour suppressor MTF2. Our results demonstrate that PCIF1 selectively suppresses MTF2 translation, activating oncogenic pathways that promote OSCC growth. In vitro and in vivo models confirm that PCIF1 knockdown reduces OSCC progression, whereas MTF2 knockdown counteracts this effect, highlighting the importance of the PCIF1-MTF2 axis. Clinical analyses further reveal that high PCIF1 expression and low MTF2 expression correlate with advanced tumour stage, poor treatment response and decreased overall survival. Furthermore, in a preclinical mouse model, PCIF1 knockout enhanced the efficacy of anti-PD1 immunotherapy, reducing tumour burden and improving histological outcomes. Notably, flow cytometry analysis indicated that PCIF1 primarily exerts its effects through tumour-intrinsic mechanisms rather than direct modulation of the immune microenvironment, distinguishing its mode of action from PD1 blockade. These findings establish PCIF1 and MTF2 as promising prognostic markers and therapeutic targets for OSCC, offering new avenues for treatment strategies and patient stratification. KEY POINTS: PCIF1 promotes OSCC progression via m6Am methylation at the MTF2 mRNA 5' cap. m6Am methylation suppresses MTF2 translation, enhancing tumour cell proliferation and invasion. Targeting PCIF1 holds therapeutic potential for OSCC treatment.

Therapeutic Nanomaterials in NAFLD: Current Advances and Potential Applications in Patients with Concurrent HBV Infection

Due to the high prevalence of non-alcoholic fatty liver disease (NAFLD) and chronic hepatitis B virus (HBV) infection, a significant proportion of patients suffer from both conditions simultaneously. The management of NAFLD in patients with concurrent HBV infection presents unique challenges, primarily due to the complex interplay between these two diseases. Nanomaterials have gained widespread attention due to their ability to overcome the limitations of conventional therapies. This review provides an overview of the current advances in therapeutic nanomaterials for NAFLD and explores their potential applications for personalized and effective management in patients with concurrent HBV infection. Furthermore, we discuss the challenges and future directions in the development of nanomaterials for the treatment of coexisting liver diseases.

New insights into T cell metabolism in liver cancer: from mechanism to therapy

Liver cancer is the sixth most common cancer worldwide and the third most common cause of cancer mortality. The development and progression of liver cancer and metastases is a multifaceted process involving numerous metabolic pathways. T cells have a protective role in the defense against cancer, and manipulating metabolic pathways in T cells can alter their antitumor activity. Furthermore, Liver cancer and T cell nutrition competition lead to T cell dysfunction through various molecular mechanisms. Some nanomaterials and drugs can improve T cell metabolism and promote the anti-liver cancer function of T cells. This review discusses the current literature regarding metabolic changes in liver cancer, the role of T cells in liver cancer, T cell metabolism in liver cancer, and targeted T cell metabolism therapy for liver cancer. The promise and challenges of studying target T cell metabolism for treating liver cancer are also addressed. Targeting T cell metabolism is a promising approach for treating liver cancer.

LPIN3 promotes colorectal cancer growth by dampening intratumoral CD8+ T cell effector function

LPIN3 has emerged as a key factor in a variety of malignancies, although its precise role in colorectal cancer (CRC) remains unclear. By analyzing the data from The Cancer Genome Atlas, we discovered that the expression pattern of LPIN3 and the relevant makeup of the immune microenvironment were immensely diverse among tumors. LPIN3 is abundantly expressed in CRC and may enhance tumor growth by activating the β-catenin signaling pathway. In addition, we discovered that LPIN3 might reduce tumor antigen presentation signals, hence suppressing CD8+ T cell-mediated cytotoxicity. Furthermore, high expression of LPIN3 predicts decreased CD8+ T cell infiltration and effector function via bioinformatics analysis. Indeed, CD8+ T cell-mediated cytotoxicity as well as CD8+ T cell infiltration and activation in vivo were strengthened by LPIN3 knockdown. To sum up, our results highlight the part that LPIN3 plays in driving the progression of CRC by regulating β-catenin signaling and CD8+ T cell activity.

METTL3-Mediated m6A Modification Regulates the Polycomb Repressive Complex 1 Components BMI1 and RNF2 in Hepatocellular Carcinoma Cells

Methyltransferase-like 3 (METTL3) is a primary RNA methyltransferase that catalyzes N6-methyladenosine (m6A) modification. The current study aims to further delineate the effect and mechanism of METTL3 in hepatocellular carcinoma (HCC). By using a murine model of hepatocellular cancer development induced via hydrodynamic tail vein injection, we showed that METTL3 enhanced HCC development. In cultured human HCC cell lines (Huh7 and PLC/PRF/5), we observed that stable knockdown of METTL3 by short hairpin RNA significantly decreased tumor cell proliferation, colony formation, and invasion, in vitro. When Huh7 and PLC/PRF/5 cells with short hairpin RNA knockdown of METTL3 were inoculated into the livers of SCID mice, we found that METTL3 knockdown significantly inhibited the growth of HCC xenograft tumors. These findings establish METTL3 as an important oncogene in HCC. Through m6A sequencing, RNA sequencing, and subsequent validation studies, we identified BMI1 and RNF2, two key components of the polycomb repressive complex 1, as direct downstream targets of METTL3-mediated m6A modification in HCC cells. Our data indicated that METTL3 catalyzed m6A modification of BMI1 and RNF2 mRNAs which led to increased mRNA stability via the m6A reader proteins IGF2BP1/2/3. Furthermore, we showed that the METTL3 inhibitor, STM2457, significantly inhibited HCC cell growth in vitro and in mice. Collectively, this study provides novel evidence that METTL3 promotes HCC development and progression through m6A modification of BMI1 and RNF2. Our findings suggest that the METTL3-m6A-BMI1/RNF2 signaling axis may represent a new therapeutic target for the treatment of HCC. Implications: The METTL3-m6A-BMI1/RNF2 signaling axis promotes HCC development and progression.

METTL3-Mediated m6A Methylation Stabilizes IFI27 to Drive Esophageal Squamous Cell Carcinoma Progression Through an IGF2BP2-Dependent Mechanism

Dysregulation of m6A modification has emerged as a vital factor in the development of esophageal squamous cell carcinoma (ESCC). Here, we sought to explore the critical role of m6A methylation mediated by the m6A methyltransferase METTL3 in ESCC. Protein expression analysis was performed by immunohistochemistry and immunoblot assays. The mRNA levels of METTL3 and IFI27 were detected by quantitative PCR. Cell sphere formation potential, migration, invasiveness, apoptosis, proliferation and viability were assessed by standard sphere formation, wound healing, transwell, flow cytometry, EdU and CCK-8 assays, respectively. The impact of METTL3 or IGF2BP2 on IFI27 mRNA was evaluated by methylated RNA immunoprecipitation (MeRIP), RIP or mRNA stability analysis. Xenograft assays were used to detect the in vivo function of METTL3. Elevated levels of METTL3 were observed in ESCC tumors and cells, and these increased levels were associated with the declined prognosis of ESCC. MELLT3 depletion impeded ESCC cell growth, invasiveness, migration, and sphere formation, and induced cell apoptosis in vitro. Elevated IFI27 expression was positively correlated with METTL3 levels in ESCC. Moreover, METTL3 mediated m6A methylation of IFI27 mRNA to stabilize the mRNA. The m6A reader IGF2BP2 also affected m6A methylation and expression of IFI27 mRNA. Additionally, IFI27 re-expression had a counteracting impact on the effects of METTL3 deficiency on in vitro ESCC cell behaviors and in vivo KYSE30 xenograft growth. Our findings demonstrate that METTL3-mediated IFI27 mRNA m6A methylation drives ESCC development through an IGF2BP2-dependent mechanism. Blocking the METTL3/IFI27 axis may be effective for preventing ESCC.

m6A RNA methylation: a pivotal regulator of tumor immunity and a promising target for cancer immunotherapy

M6A modification is one of the most common regulatory mechanisms of gene expression in eukaryotic cells, influencing processes such as RNA splicing, degradation, stability, and protein translation. Studies have shown that m6A methylation is closely associated with tumorigenesis and progression, and it plays a key regulatory role in tumor immune responses. m6A modification participates in regulating the differentiation and maturation of immune cells, as well as related anti-tumor immune responses. In the tumor microenvironment, m6A modification can also affect immune cell recruitment, activation, and polarization, thereby promoting or inhibiting tumor cell proliferation and metastasis, and reshaping the tumor immune microenvironment. In recent years, immunotherapies for tumors, such as immune checkpoint inhibitors and adoptive cell immunotherapy, have been increasingly applied in clinical settings, achieving favorable outcomes. Targeting m6A modifications to modulate the immune system, such as using small-molecule inhibitors to target dysregulated m6A regulatory factors or inducing immune cell reprogramming, can enhance anti-tumor immune responses and strengthen immune cell recognition and cytotoxicity against tumor cells. m6A modification represents a new direction in tumor immunotherapy with promising clinical potential. This review discusses the regulatory role of m6A methylation on immune cells and tumor immune responses and explores new strategies for immunotherapy.

Sophisticated roles of tumor microenvironment in resistance to immune checkpoint blockade therapy in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) remains a serious threat to global health, with rising incidence and mortality rates. Therapeutic options for advanced HCC are quite limited, and the overall prognosis remains poor. Recent advancements in immunotherapy, particularly immune-checkpoint blockade (ICB) targeting anti-PD1/PD-L1 and anti-CTLA4, have facilitated a paradigm shift in cancer treatment, demonstrating substantial survival benefits across various cancer types, including HCC. However, only a subset of HCC patients exhibit a favorable response to ICB therapy, and its efficacy is often hindered by the development of resistance. There are many studies to explore the underlying mechanisms of ICB response. In this review, we compiled the latest progression in immunotherapies for HCC and systematically summarized the sophisticated mechanisms by which components of the tumor microenvironment (TME) regulate resistance to ICB therapy. Additionally, we also outlined some scientific rationale strategies to boost antitumor immunity and enhance the efficacy of ICB in HCC. These insights may serve as a roadmap for future research and help improve outcomes for HCC patients.

The m6A revolution: transforming tumor immunity and enhancing immunotherapy outcomes

N6-methyladenosine (m6A), the most prevalent RNA modification in eukaryotes, plays a critical role in the development and progression of various diseases, including cancer, through its regulation of RNA degradation, stabilization, splicing, and cap-independent translation. Emerging evidence underscores the significant role of m6A modifications in both pro-tumorigenic and anti-tumorigenic immune responses. In this review, we provide a comprehensive overview of m6A modifications and examine the relationship between m6A regulators and cancer immune responses. Additionally, we summarize recent advances in understanding how m6A modifications influence tumor immune responses by directly modulating immune cells (e.g., dendritic cells, tumor-associated macrophages, and T cells) and indirectly affecting cancer cells via mechanisms such as cytokine and chemokine regulation, modulation of cell surface molecules, and metabolic reprogramming. Furthermore, we explore the potential synergistic effects of targeting m6A regulators in combination with immune checkpoint inhibitor (ICI) therapies. Together, this review consolidates current knowledge on the role of m6A-mediated regulation in tumor immunity, offering insights into how a deeper understanding of these modifications may identify patients who are most likely to benefit from immunotherapies.

Effect of surgery on overall survival and cancer-specific survival in patients with primary HCC: A study based on PSM in the SEER cohort

This study was designed to assess the effects of surgery method on overall survival (OS) and cancer-specific survival (CSS) in patients with hepatocellular carcinoma (HCC). This is a retrospective study. Patients diagnosed with primary HCC (N = 10,174) were identified from the Surveillance, Epidemiology, and End Results Database from 2010 to 2017 and categorized into surgical (N = 4950) and nonsurgical (N = 5224) groups. The characteristics of patients were balanced by propensity score matching. Multivariate Cox analysis was used to explore independent prognostic factors for outcomes in both groups, and the Kaplan-Meier curve showed survival rates in each group. The surgical patients were subclassified by surgical method, whether local tumor destruction, wedge or segmental resection, lobotomy resection, or liver transplantation (LT). Finally, survival rates in the 2 groups were investigated by subgroup analysis. After propensity score matching, sex, grade, tumor node metastasis III/IV, surgery, chemotherapy, alpha-fetoprotein, number of regional lymph nodes, other race, and age > 70 were independent prognostic factors in the 2 groups. The OS (HR = 0.290, P < .001) and CSS (HR = 0.274, P < .001) rates of patients were higher in the surgical group than in the nonsurgical group. There was no obvious improvement in CSS in patients who received radiotherapy combined with surgery compared with patients who only received radiotherapy (HR = 0.813, P = .279). LT was consistently found to be the best of the 4 surgical methods. The OS of stage II patients undergoing LT was better than that of corresponding stage III patients, and lobectomy resection was the best choice for stage IV patients (HR = 0. 417, P = .023). In grade III patients, the median CSS time was longer than the OS time. The survival rate of patients treated with chemotherapy combined with LT was higher than that of patients who did not receive chemotherapy and only received LT. Patients with HCC who underwent surgery had better OS and CSS. Subgroup analysis showed that LT can improve the survival rate and median survival time of patients.

Inhibition of Mettl3 by STM2457 and Loss of Macrophage Mettl3 Alleviate Pulmonary Hypertension and Right Heart Remodeling

BACKGROUND

m6A RNA methylation is a critical epigenetic modification involved in the pathogenesis of pulmonary arterial hypertension (PAH). While macrophage-mediated inflammation plays a central role in PAH, the specific contributions of m6A regulators within macrophages are not yet fully understood. This study explores the role of METTL3 in macrophages, with particular emphasis on its contribution to the progression of PAH.

METHODS

SU5416/Hypoxia (SuHx) PAH mouse models were treated daily with STM2457, a selective METTL3 antagonist, or vehicle for 10 days. Additionally, SuHx PAH was induced in Mettl3flox/floxlyz2cre + and Mettl3flox/flox mice using genetic approaches. Pulmonary acceleration time to pulmonary ejection time (PAAT/PAET) and right ventricular free wall (RVFWD) were measured by ultrasound. Hemodynamic parameters, including right ventricular systolic pressure (RVSP), were assessed. Pulmonary vascular and right heart remodeling were evaluated using HE staining, while vascular and right heart fibrosis were assessed by Masson's trichrome staining. The expression of fibrosis-associated genes was quantified by qPCR. Macrophage activation in tissues was determined via CD86 and CD206 immunofluorescence staining, and the expression of inflammatory cytokines and fibrosis-associated genes was quantified by qPCR.

RESULTS

METTL3 expression was significantly upregulated in the lungs and macrophages of PAH models. Treatment with STM2457 reversed the progression of SuHx PAH, as evidenced by a reduction in RVSP, attenuation of pulmonary vascular and right heart remodeling, and decreased fibrosis in both the heart and lungs. Furthermore, the expression of fibrosis-associated genes in the right heart, including Col1a1, Col1a3, and α-SMA, was downregulated following STM2457 treatment and METTL3 depletion in macrophages. Both STM2457 treatment and METTL3 depletion resulted in a significant reduction in the number of CD86+ and CD206+ macrophages, accompanied by a suppression of pro-inflammatory cytokines such as IL-1β and iNOS, alongside an upregulation of anti-inflammatory cytokines, including IL-10 and Arg1.

CONCLUSION

STM2457 treatment and METTL3 depletion in macrophages effectively reversed SuHx PAH by modulating macrophage inflammatory responses and alleviating pulmonary vascular and right heart remodeling, as well as fibrosis. These findings underscore the role of METTL3 in PAH pathogenesis by regulating macrophage function and inflammation.

m6A epitranscriptomic modification in hepatocellular carcinoma: implications for the tumor microenvironment and immunotherapy

Hepatocellular carcinoma (HCC) is the most prevalent primary liver malignancy and a leading cause of cancer-related deaths globally. The asymptomatic progression of early-stage HCC often results in diagnosis at advanced stages, significantly limiting therapeutic options and worsening prognosis. Immunotherapy, with immune checkpoint inhibitors (ICIs) at the forefront, has revolutionized HCC treatment. Nevertheless, tumor heterogeneity, immune evasion, and the presence of immunosuppressive components within the tumor immune microenvironment (TIME) continue to compromise its efficacy. Furthermore, resistance or non-responsiveness to ICIs in some patients underscores the urgent need to unravel the complexities of the TIME and to design innovative strategies that enhance immunotherapeutic outcomes. Emerging evidence has revealed the pivotal role of N6-methyladenosine (m6A), a prominent RNA methylation modification, in shaping the TIME in HCC. By regulating RNA stability and translation, m6A influences immune-related factors, including cytokines and immune checkpoint molecules. This modification governs PD-L1 expression, facilitating immune escape and contributing to resistance against ICIs. Advances in this field have also identified m6A-related regulators as promising biomarkers for predicting immunotherapy response and as potential therapeutic targets for optimizing treatment efficacy. This review examines the regulatory mechanisms of m6A modification within the TIME of HCC, with a focus on its impact on immune cells and cytokine dynamics. It also explores the therapeutic potential of targeting m6A pathways to improve immunotherapy efficacy and outlines emerging directions for future research. These insights aim to provide a foundation for developing novel strategies to overcome immune resistance and advance HCC treatment.

Exploring m6A modifications in gastric cancer: from molecular mechanisms to clinical applications

The significance of m6A modifications in several biological processes has been increasingly recognized, particularly in the context of cancer. For instance, m6A modifications in gastric cancer (GC) have been significantly implicated in tumor progression, metastasis, and treatment resistance. GC is characterized by the differential expression of m6A regulators. High expression writers such as METTL3 and WTAP are associated with poor prognosis and aggressive clinical features. Conversely, low expression of METTL14 is linked to worse clinical outcomes, whereas elevated levels of demethylases, such as FTO and ALKBH5, correlate with better survival rates. These m6A regulators influence several cellular biological functions, including proliferation, invasion, migration, glycolysis, and chemotherapy resistance, thereby affecting tumor growth and therapeutic outcomes. The assessment of m6A modification patterns and the expression profiles of m6A-related genes hold substantial potential for improving the clinical diagnosis and treatment of GC. In this review, we provide an updated and comprehensive summary of the role of m6A modifications in GC, emphasizing their molecular mechanisms, clinical significance, and translational applications in developing novel diagnostic and therapeutic strategies.

The diverse landscape of RNA modifications in cancer development and progression

BACKGROUND

RNA modifications, a central aspect of epitranscriptomics, add a regulatory layer to gene expression by modifying RNA function without altering nucleotide sequences. These modifications play vital roles across RNA species, influencing RNA stability, translation, and interaction dynamics, and are regulated by specific enzymes that add, remove, and interpret these chemical marks.

OBJECTIVE

This review examines the role of aberrant RNA modifications in cancer progression, exploring their potential as diagnostic and prognostic biomarkers and as therapeutic targets. We focus on how altered RNA modification patterns impact oncogenes, tumor suppressor genes, and overall tumor behavior.

METHODS

We performed an in-depth analysis of recent studies and advances in RNA modification research, highlighting key types and functions of RNA modifications and their roles in cancer biology. Studies involving preclinical models targeting RNA-modifying enzymes were reviewed to assess therapeutic efficacy and potential clinical applications.

RESULTS

Aberrant RNA modifications were found to significantly influence cancer initiation, growth, and metastasis. Dysregulation of RNA-modifying enzymes led to altered gene expression profiles in oncogenes and tumor suppressors, correlating with tumor aggressiveness, patient outcomes, and response to immunotherapy. Notably, inhibitors of these enzymes demonstrated potential in preclinical models by reducing tumor growth and enhancing the efficacy of existing cancer treatments.

CONCLUSIONS

RNA modifications present promising avenues for cancer diagnosis, prognosis, and therapy. Understanding the mechanisms of RNA modification dysregulation is essential for developing targeted treatments that improve patient outcomes. Further research will deepen insights into these pathways and support the clinical translation of RNA modification-targeted therapies.

Preventing postsurgical colorectal cancer relapse: A hemostatic hydrogel loaded with METTL3 inhibitor for CAR-NK cell therapy

Colorectal cancer (CRC) recurrence post-surgery remains a major challenge. While Chimeric Antigen Receptor (CAR)-engineered natural killer (NK) cells hold immense therapeutic potential, their intratumoral infiltration ability remains limited, hampering efficacy. Building upon prior research suggesting that chemokines like C-X-C motif chemokine ligand 9 (CXCL9) and C-X-C motif chemokine ligand 10 (CXCL10) recruit CAR-NK cells, we hypothesized that tumor cell m6A methylation, regulated by Methyltransferase-like 3 (METTL3), influences chemokine secretion. This study aims to elucidate the underlying mechanisms and improve METTL3 inhibition efficiency. We designed an adhesive hemostasis hydrogel loaded with STM2457, a METTL3 inhibitor, aimed at sustained release in the acidic tumor microenvironment. In vitro, the hydrogel promoted CAR-NK cell recruitment and tumor killing via sustained METTL3 inhibition. The hydrogel's Schiff base bonds further enabled intestinal adhesion and hemostasis in an incomplete tumor resection model of CRC. Combining the hydrogel with CAR-NK cell therapy significantly reduced CRC recurrence in vivo. Overall, our study reveals the crucial role of METTL3 in CRC recurrence and proposes a promising, multimodal strategy using STM2457-loaded hydrogel and CAR-NK cells for enhanced therapeutic efficacy.

METTL3: a multifunctional regulator in diseases

N6-methyladenosine (m6A) methylation is the most prevalent and abundant internal modification of mRNAs and is catalyzed by the methyltransferase complex. Methyltransferase-like 3 (METTL3), the best-known m6A methyltransferase, has been confirmed to function as a multifunctional regulator in the reversible epitranscriptome modulation of m6A modification according to follow-up studies. Accumulating evidence in recent years has shown that METTL3 can regulate a variety of functional genes, that aberrant expression of METTL3 is usually associated with many pathological conditions, and that its expression regulatory mechanism is related mainly to its methyltransferase activity or mRNA posttranslational modification. In this review, we discuss the regulatory functions of METTL3 in various diseases, including metabolic diseases, cardiovascular diseases, and cancer. We focus mainly on recent progress in identifying the downstream target genes of METTL3 and its underlying molecular mechanisms and regulators in the above systems. Studies have revealed that the use of METTL3 as a therapeutic target and a new diagnostic biomarker has broad prospects. We hope that this review can serve as a reference for further studies.

New insights into N6-methyladenosine in hepatocellular carcinoma immunotherapy

N6-methylation is a modification in which a methyl group is added to the adenine base of a nucleotide. This modification is crucial for controlling important functions that are vital for gene expression, including mRNA splicing, stability, and translation. Due to its intricate participation in both normal cellular processes and the course of disease, as well as its critical role in determining cell fate, N6-methyladenosine (m6A) alteration has recently attracted a lot of interest. The formation and progression of many diseases, especially cancer, can be attributed to dysregulated m6A alteration, which can cause disturbances in a variety of cellular functions, such as immunological responses, cell proliferation, and differentiation. In this study, we examine how m6A dysregulation affects hepatocellular carcinoma (HCC), with a particular emphasis on how it contributes to immunological evasion and carcinogenesis. We also investigate its potential as a novel therapeutic target, providing new perspectives on potential therapeutic approaches meant to enhance clinical results for patients with HCC.

Interplay between gut microbiome, host genetic and epigenetic modifications in MASLD and MASLD-related hepatocellular carcinoma

Metabolic dysfunction-associated steatotic liver disease (MASLD) encompasses a wide spectrum of liver injuries, ranging from hepatic steatosis, metabolic dysfunction-associated steatohepatitis (MASH), fibrosis, cirrhosis to MASLD-associated hepatocellular carcinoma (MASLD-HCC). Recent studies have highlighted the bidirectional impacts between host genetics/epigenetics and the gut microbial community. Host genetics influence the composition of gut microbiome, while the gut microbiota and their derived metabolites can induce host epigenetic modifications to affect the development of MASLD. The exploration of the intricate relationship between the gut microbiome and the genetic/epigenetic makeup of the host is anticipated to yield promising avenues for therapeutic interventions targeting MASLD and its associated conditions. In this review, we summarise the effects of gut microbiome, host genetics and epigenetic alterations in MASLD and MASLD-HCC. We further discuss research findings demonstrating the bidirectional impacts between gut microbiome and host genetics/epigenetics, emphasising the significance of this interconnection in MASLD prevention and treatment.

The expression of Methyltransferase-like 3 in dentigerous cyst and ameloblastoma

Background

N6-methyladenosine (m6A), the most abundant internal RNA modification in mammals, plays a critical role in many forms of cancer. Methyltransferase-like 3 (METTL3) serves as the main catalytic subunit of the m6A writer and plays a role in the progression of head and neck squamous cell carcinoma. To date, the role of METTL3 in odontogenic lesions has never been investigated. This study aimed to examine METTL3 expression in dental follicles (DF), dentigerous cysts (DC), unicystic ameloblastoma (UA), and conventional ameloblastoma (conventional AM).

Material and Methods

The immunohistochemistry was performed using paraffin-embedded tissue samples. Seven cases of DF, 30 cases of DC, and 35 cases of AM (20 cases of UA and 15 cases of conventional AM) were included. The expression patterns, percentage of METTL3-positive cells, staining intensities, and immunoreactive scores (IRS) were examined.

Results

The percentage of METTL3-positive cells was found to be significantly higher in the AM compared to DC and DF samples (p<0.01). Additionally, the percentage of METTL3-positive cells increased from the luminal/intraluminal subtype of UA, the mural subtype of UA, to the conventional AM (p<0.01). All AM samples had higher METTL3 cell staining intensity and IRS scores than the DF and DC samples (p<0.01). The mural subtype of UA and conventional AM also had significantly higher cell intensity and IRS scores than the luminal/intraluminal subtype of UA (p<0.05).

Conclusions

The results of this study suggest that METTL3 might have a role in odontogenic lesions. METTL3 expression may be related to the aggressive behaviour of these lesions. However, the precise molecular mechanism of METTL3 in odontogenic lesions still needs to be elucidated. Key words:Methyltransferase-like 3, immunohistochemistry, dentigerous cyst, ameloblastoma.

Omics-Enhanced Nanomedicine for Cancer Therapy

Cancer nanomedicine has emerged as a promising approach to overcome the limitations of conventional cancer therapies, offering enhanced efficacy and safety in cancer management. However, the inherent heterogeneity of tumors presents increasing challenges for the application of cancer nanomedicine in both diagnosis and treatment. This heterogeneity necessitates the integration of advanced and high-throughput analytical techniques to tailor nanomedicine strategies to individual tumor profiles. Omics technologies, encompassing genomics, epigenomics, transcriptomics, proteomics, metabolomics, and more, provide unparalleled insights into the molecular and cellular mechanisms underlying cancer. By dissecting tumor heterogeneity across multiple levels, these technologies offer robust support for the development of personalized and precise cancer nanomedicine strategies. In this review, the principles, techniques, and applications of key omics technologies are summarized. Especially, the synergistic integration of omics and nanomedicine in cancer therapy is explored, focusing on enhanced diagnostic accuracy, optimized therapeutic strategies and the assessment of nanomedicine-mediated biological responses. Moreover, this review addresses current challenges and outlines future directions in the field of omics-enhanced nanomedicine. By offering valuable insights and guidance, this review aims to advance the integration of omics with nanomedicine, ultimately driving improved diagnostic and therapeutic strategies for cancer.

Peptide Degrader-Based Targeting of METTL3/14 Improves Immunotherapy Response in Cutaneous Melanoma

METTL3 has emerged as a promising therapeutic target in cancer treatment, although its oncogenic functions in melanoma development and potential for therapeutic targeting drug have not been fully explored. In this study, we define the oncogenic role of METTL3 in melanoma development and progression. Building on this insight, we examine our recently designed peptide inhibitor RM3, which targets the binding interface of METTL3/14 complex for disruption and subsequent ubiquitin-mediated proteasomal degradation via the E3 ligase STUB1. RM3 treatment reduces proliferation, migration, and invasion, and induces apoptosis in melanoma cells in vitro and in vivo. Subsequent transcriptomic analysis identified changes in immuno-related genes following RM3-mediated suppression of METTL3/14 N6-methyladenosine (m6A) methyltransferase activity, suggesting a potential for interaction with immunotherapy. A combination treatment of RM3 with anti-PD-1 antibody results in significantly higher beneficial tumor response in vivo, with a good safety profile. Collectively, these findings not only delineate the oncogenic role of METTL3 in melanoma but also showcase RM3, acting as a peptide degrader, as a novel and promising strategy for melanoma treatment.

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.

METTL3-mediated m6A modification promotes chemoresistance of intrahepatic cholangiocarcinoma by up-regulating NRF2 to inhibit ferroptosis in cisplatin-resistant cells

This study explores the relationship between m6A modification and ferroptosis in intrahepatic cholangiocarcinoma (ICC) and its impact on cisplatin resistance. We established cisplatin-resistant cells. CCK-8 and Transwell assays were conducted to evaluate the effects of METTL3 on drug resistance, migration, and invasion. RT-qPCR and Western blotting were used to measure target gene expression and the effects of overexpression and suppression. RIP, luciferase reporter assay, and other experiments were utilized to investigate the interaction between METTL3 and NRF2. Additionally, rescue experiments were performed to confirm the role of the METTL3/NRF2 axis in tumor drug resistance. METTL3 was found to be highly expressed in cisplatin-resistant cells, enhancing m6A modification levels, stabilizing NRF2 mRNA, and increasing NRF2 protein expression to inhibit ferroptosis. These findings indicate that the METTL3/NRF2 axis inhibits ferroptosis in cisplatin-resistant cells, thereby promoting chemotherapy resistance in ICC. This provides a potential direction for future research and treatment of ICC.

RNA modifications in the progression of liver diseases: from fatty liver to cancer

Non-alcoholic fatty liver disease (NAFLD) has emerged as a prominent global health concern associated with high risk of metabolic syndrome, and has impacted a substantial segment of the population. The disease spectrum ranges from simple fatty liver to non-alcoholic steatohepatitis (NASH), which can progress to cirrhosis and hepatocellular carcinoma (HCC) and is increasingly becoming a prevalent indication for liver transplantation. The existing therapeutic options for NAFLD, NASH, and HCC are limited, underscoring the urgent need for innovative treatment strategies. Insights into gene expression, particularly RNA modifications such as N6 methyladenosine (m6A), hold promising avenues for interventions. These modifications play integral roles in RNA metabolism and cellular functions, encompassing the entire NAFLD-NASH-HCC progression. This review will encompass recent insights on diverse RNA modifications, including m6A, pseudouridine (ψ), N1-methyladenosine (m1A), and 5-methylcytidine (m5C) across various RNA species. It will uncover their significance in crucial aspects such as steatosis, inflammation, fibrosis, and tumorigenesis. Furthermore, prospective research directions and therapeutic implications will be explored, advancing our comprehensive understanding of the intricate interconnected nature of these pathological conditions.

RNA modifications in cancer immune therapy: regulators of immune cells and immune checkpoints

RNA modifications are epigenetic changes that alter the structure and function of RNA molecules, playing a crucial role in the onset, progression, and treatment of cancer. Immune checkpoint inhibitor (ICI) therapies, particularly PD-1 blockade and anti-CTLA-4 treatments, have changed the treatment landscape of virous cancers, showing great potential in the treatment of different cancer patients, but sensitivity to these therapies is limited to certain individuals. This review offers a comprehensive survey of the functions and therapeutic implications of the four principal RNA modifications, particularly highlighting the significance of m6A in the realms of immune cells in tumor and immunotherapy. This review starts by providing a foundational summary of the roles RNA modifications assume within the immune cell community, focusing on T cells, NK cells, macrophages, and dendritic cells. We then discuss how RNA modifications influence the intricate regulatory mechanisms governing immune checkpoint expression, modulation of ICI efficacy, and prediction of ICI treatment outcomes, and review drug therapies targeting genes regulated by RNA modifications. Finally, we explore the role of RNA modifications in gene editing, cancer vaccines, and adoptive T cell therapies, offering valuable insights into the use of RNA modifications in cancer immunotherapy.

Role of N6-methyladenosine RNA modification in cancer

N6-methyladenosine (m6A) is the most abundant modification of RNA in eukaryotic cells. Previous studies have shown that m6A is pivotal in diverse diseases especially cancer. m6A corelates with the initiation, progression, resistance, invasion, and metastasis of cancer. However, despite these insights, a comprehensive understanding of its specific roles and mechanisms within the complex landscape of cancer is still elusive. This review begins by outlining the key regulatory proteins of m6A modification and their posttranslational modifications (PTMs), as well as the role in chromatin accessibility and transcriptional activity within cancer cells. Additionally, it highlights that m6A modifications impact cancer progression by modulating programmed cell death mechanisms and affecting the tumor microenvironment through various cancer-associated immune cells. Furthermore, the review discusses how microorganisms can induce enduring epigenetic changes and oncogenic effect in microorganism-associated cancers by altering m6A modifications. Last, it delves into the role of m6A modification in cancer immunotherapy, encompassing RNA therapy, immune checkpoint blockade, cytokine therapy, adoptive cell transfer therapy, and direct targeting of m6A regulators. Overall, this review clarifies the multifaceted role of m6A modification in cancer and explores targeted therapies aimed at manipulating m6A modification, aiming to advance cancer research and improve patient outcomes.

Research progress of SREBP and its role in the pathogenesis of autoimmune rheumatic diseases

Autoimmune rheumatic diseases comprise a group of immune-related disorders characterized by non-organ-specific inflammation. These diseases include systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), ankylosing spondylitis (AS), gout, among others. Typically involving the hematologic system, these diseases may also affect multiple organs and systems. The pathogenesis of autoimmune rheumatic immune diseases is complex, with diverse etiologies, all associated with immune dysfunction. The current treatment options for this type of disease are relatively limited and come with certain side effects. Therefore, the urgent challenge remains to identify novel therapeutic targets for these diseases. Sterol regulatory element-binding proteins (SREBPs) are basic helix-loop-helix-leucine zipper transcription factors that regulate the expression of genes involved in lipid and cholesterol biosynthesis. The expression and transcriptional activity of SREBPs can be modulated by extracellular stimuli such as polyunsaturated fatty acids, amino acids, glucose, and energy pathways including AKT-mTORC and AMP-activated protein kinase (AMPK). Studies have shown that SREBPs play roles in regulating lipid metabolism, cytokine production, inflammation, and the proliferation of germinal center B (GCB) cells. These functions are significant in the pathogenesis of rheumatic and immune diseases (Graphical abstract). Therefore, this paper reviews the potential mechanisms of SREBPs in the development of SLE, RA, and gout, based on an exploration of their functions.

Regulations of m6A and other RNA modifications and their roles in cancer

RNA modification is an essential component of the epitranscriptome, regulating RNA metabolism and cellular functions. Several types of RNA modifications have been identified to date; they include N6-methyladenosine (m6A), N1-methyladenosine (m1A), 5-methylcytosine (m5C), N7-methylguanosine (m7G), N6,2'-O-dimethyladenosine (m6Am), N4-acetylcytidine (ac4C), etc. RNA modifications, mediated by regulators including writers, erasers, and readers, are associated with carcinogenesis, tumor microenvironment, metabolic reprogramming, immunosuppression, immunotherapy, chemotherapy, etc. A novel perspective indicates that regulatory subunits and post-translational modifications (PTMs) are involved in the regulation of writer, eraser, and reader functions in mediating RNA modifications, tumorigenesis, and anticancer therapy. In this review, we summarize the advances made in the knowledge of different RNA modifications (especially m6A) and focus on RNA modification regulators with functions modulated by a series of factors in cancer, including regulatory subunits (proteins, noncoding RNA or peptides encoded by long noncoding RNA) and PTMs (acetylation, SUMOylation, lactylation, phosphorylation, etc.). We also delineate the relationship between RNA modification regulator functions and carcinogenesis or cancer progression. Additionally, inhibitors that target RNA modification regulators for anticancer therapy and their synergistic effect combined with immunotherapy or chemotherapy are discussed.

Crosstalk between Epigenetics and Metabolic Reprogramming in Metabolic Dysfunction-Associated Steatotic Liver Disease-Induced Hepatocellular Carcinoma: A New Sight

Epigenetic and metabolic reprogramming alterations are two important features of tumors, and their reversible, spatial, and temporal regulation is a distinctive hallmark of carcinogenesis. Epigenetics, which focuses on gene regulatory mechanisms beyond the DNA sequence, is a new entry point for tumor therapy. Moreover, metabolic reprogramming drives hepatocellular carcinoma (HCC) initiation and progression, highlighting the significance of metabolism in this disease. Exploring the inter-regulatory relationship between tumor metabolic reprogramming and epigenetic modification has become one of the hot directions in current tumor metabolism research. As viral etiologies have given way to metabolic dysfunction-associated steatotic liver disease (MASLD)-induced HCC, it is urgent that complex molecular pathways linking them and hepatocarcinogenesis be explored. However, how aberrant crosstalk between epigenetic modifications and metabolic reprogramming affects MASLD-induced HCC lacks comprehensive understanding. A better understanding of their linkages is necessary and urgent to improve HCC treatment strategies. For this reason, this review examines the interwoven landscape of molecular carcinogenesis in the context of MASLD-induced HCC, focusing on mechanisms regulating aberrant epigenetic alterations and metabolic reprogramming in the development of MASLD-induced HCC and interactions between them while also updating the current advances in metabolism and epigenetic modification-based therapeutic drugs in HCC.

The switch triggering the invasion process: Lipid metabolism in the metastasis of hepatocellular carcinoma

ABSTRACT

In humans, the liver is a central metabolic organ with a complex and unique histological microenvironment. Hepatocellular carcinoma (HCC), which is a highly aggressive disease with a poor prognosis, accounts for most cases of primary liver cancer. As an emerging hallmark of cancers, metabolic reprogramming acts as a runaway mechanism that disrupts homeostasis of the affected organs, including the liver. Specifically, rewiring of the liver metabolic microenvironment, including lipid metabolism, is driven by HCC cells, propelling the phenotypes of HCC cells, including dissemination, invasion, and even metastasis in return. The resulting formation of this vicious loop facilitates various malignant behaviors of HCC further. However, few articles have comprehensively summarized lipid reprogramming in HCC metastasis. Here, we have reviewed the general situation of the liver microenvironment and the physiological lipid metabolism in the liver, and highlighted the effects of different aspects of lipid metabolism on HCC metastasis to explore the underlying mechanisms. In addition, we have recapitulated promising therapeutic strategies targeting lipid metabolism and the effects of lipid metabolic reprogramming on the efficacy of HCC systematical therapy, aiming to offer new perspectives for targeted therapy.

Τ cell-mediated adaptive immunity in the transition from metabolic dysfunction-associated steatohepatitis to hepatocellular carcinoma

Metabolic dysfunction-associated steatohepatitis (MASH) is the progressed version of metabolic dysfunction-associated steatotic liver disease (MASLD) characterized by inflammation and fibrosis, but also a pathophysiological "hub" that favors the emergence of liver malignancies. Current research efforts aim to identify risk factors, discover disease biomarkers, and aid patient stratification in the context of MASH-induced hepatocellular carcinoma (HCC), the most prevalent cancer among MASLD patients. To investigate the tumorigenic transition in MASH-induced HCC, researchers predominantly exploit preclinical animal-based MASH models and studies based on archived human biopsies and clinical trials. Recapitulating the immune response during tumor development and progression is vital to obtain mechanistic insights into MASH-induced HCC. Notably, the advanced complexity behind MASLD and MASH pathogenesis shifted the research focus towards innate immunity, a fundamental element of the hepatic immune niche that is usually altered robustly in the course of liver disease. During the last few years, however, there has been an increasing interest for deciphering the role of adaptive immunity in MASH-induced HCC, particularly regarding the functions of the various T cell populations. To effectively understand the specific role of T cells in MASH-induced HCC development, scientists should urgently fill the current knowledge gaps in this field. Pinpointing the metabolic signature, sketching the immune landscape, and characterizing the cellular interactions and dynamics of the specific T cells within the MASH-HCC liver are essential to unravel the mechanisms that adaptive immunity exploits to enable the emergence and progression of this cancer. To this end, our review aims to summarize the current state of research regarding the T cell functions linked to MASH-induced HCC.

Molecular mechanisms in MASLD/MASH-related HCC

Liver cancer is the third leading cause of cancer-related deaths and ranks as the sixth most prevalent cancer type globally. NAFLD or metabolic dysfunction-associated steatotic liver disease, and its more severe manifestation, NASH or metabolic dysfunction-associated steatohepatitis (MASH), pose a significant global health concern, affecting approximately 20%-25% of the population. The increased prevalence of metabolic dysfunction-associated steatotic liver disease and MASH is parallel to the increasing rates of obesity-associated metabolic diseases, including type 2 diabetes, insulin resistance, and fatty liver diseases. MASH can progress to MASH-related HCC (MASH-HCC) in about 2% of cases each year, influenced by various factors such as genetic mutations, carcinogen exposure, immune microenvironment, and microbiome. MASH-HCC exhibits distinct molecular and immune characteristics compared to other causes of HCC and affects both men and women equally. The management of early to intermediate-stage MASH-HCC typically involves surgery and locoregional therapies, while advanced HCC is treated with systemic therapies, including anti-angiogenic therapies and immune checkpoint inhibitors. In this comprehensive review, we consolidate previous research findings while also providing the most current insights into the intricate molecular processes underlying MASH-HCC development. We delve into MASH-HCC-associated genetic variations and somatic mutations, disease progression and research models, multiomics analysis, immunological and microenvironmental impacts, and discuss targeted/combined therapies to overcome immune evasion and the biomarkers to recognize treatment responders. By furthering our comprehension of the molecular mechanisms underlying MASH-HCC, our goal is to catalyze the advancement of more potent treatment strategies, ultimately leading to enhanced patient outcomes.

THE ROLE OF N6-METHYLADENOSINE METHYLTRANSFERASE RBM15 IN NONALCOHOLIC FATTY LIVER DISEASE

ABSTRACT

Nonalcoholic fatty liver disease (NAFLD) is a prevalent liver disorder with significant health implications. N6-methyladenosine (m6A) methyltransferase is known to exert regulatory functions in liver-related diseases. This study investigates the intricate role of RNA binding motif protein 15 (RBM15) in modulating inflammation and oxidative stress in NAFLD. An NAFLD model was induced in mice (male, C57BL/6J, 72 mice in the sham group) through a high-fat diet for 9 weeks, and hepatocytes were exposed to long chain-free fatty acids. The expression levels of RBM15, ring finger protein 5 (RNF5), and rho-kinase 1 (ROCK1) were assessed. RBM15 expression was intervened (injection of AAV9 virus at week 9 and detection at week 11). Liver damage was evaluated using staining assays, along with assessments of weight changes and lipid levels. Notably, RBM15 (decreased approximately 40%/60%) and RNF5 (decreased approximately 60%/75%) were poorly expressed while ROCK1 (increased approximately 2.5-fold) was highly expressed in liver tissues and cells. RBM15 overexpression mitigated liver damage, inflammation, and oxidative stress in NAFLD mice, resulting in reduced liver-to-body weight ratio (20%) and decreased levels of alanine aminotransferase (54%), aspartate aminotransferase (36%), total cholesterol (30%), and triglycerides (30%), and inhibited inflammation and oxidative stress levels. Mechanistically, RBM15 upregulated RNF5 expression through m6A methylation modification, and RNF5 suppressed ROCK1 protein levels through ubiquitination modification. RNF5 knockdown or ROCK1 overexpression accelerated inflammation and oxidative stress in NAFLD. Taken together, RBM15 upregulated RNF5 expression through m6A methylation modification. RNF5 inhibited ROCK1 expression through ubiquitination modification to mitigate NAFLD.

BMP9-ID1 Pathway Attenuates N6-Methyladenosine Levels of CyclinD1 to Promote Cell Proliferation in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a highly lethal malignant neoplasm, and the involvement of bone morphogenetic protein 9 (BMP9) has been implicated in the pathogenesis of liver diseases and HCC. Our goal was to investigate the role of BMP9 signaling in regulating N6-methyladenosine (m6A) methylation and cell cycle progression, and evaluate the therapeutic potential of BMP receptor inhibitors for HCC treatment. We observed that elevated levels of BMP9 expression in tumor tissues or serum samples from HCC patients were associated with a poorer prognosis. Through in vitro experiments utilizing the m6A dot blotting assay, we ascertained that BMP9 reduced the global RNA m6A methylation level in Huh7 and Hep3B cells, thereby facilitating their cell cycle progression. This effect was mediated by an increase in the expression of the inhibitor of DNA-binding protein 1 (ID1). Additionally, using methylated RNA immunoprecipitation qPCR(MeRIP-qPCR), we showed that the BMP9-ID1 pathway promoted CyclinD1 expression by decreasing the m6A methylation level in the 5' UTR of mRNA. This occurred through the upregulation of the fat mass and obesity-associated protein (FTO) in Huh7 and Hep3B cells. In our in vivo mouse xenograft models, we demonstrated that blocking the BMP receptor with LDN-212854 effectively suppressed HCC growth and induced global RNA m6A methylation. Overall, our findings indicate that the BMP9-ID1 pathway promotes HCC cell proliferation by down-regulating the m6A methylation level in the 5' UTR of CyclinD1 mRNA. Targeting the BMP9-ID1 pathway holds promise as a potential therapeutic strategy for treating HCC.

Research Advances in the Roles of N6-Methyladenosine Modification in Ovarian Cancer

Ovarian cancer (OC) is the most lethal gynecological tumor, characterized by its insidious and frequently recurring metastatic progression. Owing to limited early screening methods, over 70% of OC cases are diagnosed at advanced stages, typically stage III or IV. Recently, N6-methyladenosine (m6A) modification has emerged as a hotspot of epigenetic research, representing a significant endogenous RNA modification in higher eukaryotes. Numerous studies have reported that m6A-related regulatory factors play pivotal roles in tumor development through diverse mechanisms. Moreover, recent studies have indicated the aberrant expression of multiple regulatory factors in OC. Therefore, this paper comprehensively reviews research advancements concerning m6A in OC, aiming to elucidate the regulatory mechanism of m6A-associated regulators on pivotal aspects, such as proliferation, invasion, metastasis, and drug resistance, in OC. Furthermore, it discusses the potential of m6A-associated regulators as early diagnostic markers and therapeutic targets, thus contributing to the diagnosis and treatment of OC.

Therapeutic effect and transcriptome-methylome characteristics of METTL3 inhibition in liver hepatocellular carcinoma

Methyltransferase-like 3 (METTL3) is the key subunit of methyltransferase complex responsible for catalyzing N6-methyladenosine (m6A) modification on mRNA, which is the most prevalent post-transcriptional modification in eukaryotes. In this study, we utilized online databases to analyze the association between METTL3 expression and various aspects of tumorigenesis, including gene methylation, immunity, and prognosis. Our investigation revealed that METTL3 serves as a prognostic marker and therapeutic target for liver hepatocellular carcinoma (LIHC). Through experimental studies, we observed frequent upregulation of METTL3 in LIHC tumor tissue and cells. Subsequent inhibition of METTL3 using a novel small molecule inhibitor, STM2457, significantly impeded tumor growth in LIHC cell lines, spheroids, and xenograft tumor model. Further, transcriptome and m6A sequencing of xenograft bodies unveiled that inhibition of METTL3-m6A altered genes enriched in SMAD and MAPK signaling pathways that are critical for tumorigenesis. These findings suggest that targeting METTL3 represents a promising therapeutic strategy for LIHC.