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Background N6-methyladenosine (m6A) methylation, a well-known modification with new epigenetic functions, has been reported to participate in the tumorigenesis of hepatocellular carcinoma (HCC), providing novel insights into the molecular pathogenesis of this disease. However, as the key component of m6A methylation, Wilms tumor 1-associated protein (WTAP) has not been well studied in HCC. Here we investigated the biological role and underlying mechanism of WTAP in liver cancer. Methods We determined the expression of WTAP and its correlation with clinicopathological features using tissue microarrays and the Cancer Genome Atlas (TCGA) dataset. And we clarified the effects of WTAP on HCC cells using cell proliferation assay, colony formation, Edu assay and subcutaneous xenograft experiments. We then applied RNA sequencing combined with gene expression omnibus (GEO) data to screen candidate targets of WTAP. Finally, we investigated the regulatory mechanism of WTAP in HCC by m6A dot blot assay, methylated RNA immunoprecipitation (MeRIP) assay, dual luciferase reporter assay, RNA immunoprecipitation (RIP) assay and Chromatin immunoprecipitation (ChIP) assay. Results We demonstrated that WTAP was highly expressed in HCC which indicated the poor prognosis, and that WTAP expression served as an independent predictor of HCC survival. Functionally, WTAP promoted the proliferation capability and tumor growth of HCC cells in vitro and in vivo. Furthermore, ETS proto-oncogene 1 (ETS1) was identified as the downstream effector of WTAP. The m6A modification regulated by WTAP led to post-transcriptional suppression of ETS1, with the implication of Hu-Antigen R (HuR) as an RNA stabilizer. Then ETS1 was found to inhibit the progression of HCC and could rescue the phenotype induced by WTAP deficiency. Moreover, WTAP modulated the G2/M phase of HCC cells through a p21/p27-dependent pattern mediated by ETS1. Conclusion We have identified that WTAP is significantly up-regulated in HCC and promotes liver cancer development. WTAP-guided m6A modification contributes to the progression of HCC via the HuR-ETS1-p21/p27 axis. Our study is the first to report that WTAP-mediated m6A methylation has a crucial role in HCC oncogenesis, and highlights WTAP as a potential therapeutic target of HCC treatment.

Background N6-methyladenosine (m 6 A) modification is an emerging layer of epigenetic regulation which is widely implicated in the tumorigenicity of hepatocellular carcinoma (HCC), offering a novel perspective for investigating molecular pathogenesis of this disease. The role of AlkB homolog 5 (ALKBH5), one of the m 6 A demethylases, has not been fully explored in HCC. Here we clarify the biological profile and potential mechanisms of ALKBH5 in HCC. Methods Expression of ALKBH5 and its correlation with clinicopathological characteristics of HCC were evaluated using tissue microarrays and online datasets. And biological effects of ALKBH5 in HCC were determined in vitro and in vivo. Subsequently, methylated RNA immunoprecipitation sequencing (MeRIP-seq) combined with RNA sequencing (RNA-seq), and following m 6 A dot blot, MeRIP-qPCR, RIP-qPCR or dual luciferase reporter assays were employed to screen and validate the candidate targets of ALKBH5. Results We demonstrated that ALKBH5 was down-regulated in HCC, and decreased ALKBH5 expression was an independent prognostic factor of worse survival in HCC patients. Functionally, ALKBH5 suppressed the proliferation and invasion capabilities of HCC cells in vitro and in vivo. Mechanistically, ALKBH5-mediated m 6 A demethylation led to a post-transcriptional inhibition of LY6/PLAUR Domain Containing 1 (LYPD1), which could be recognized and stabilized by the m 6 A effector IGF2BP1. In addition, we identified that LYPD1 induced oncogenic behaviors of tumors in contrast to ALKBH5. Dysregulation of ALKBH5/LYPD1 axis impelled the progression of HCC. Conclusion Our study reveals that ALKBH5, characterized as a tumor suppressor, attenuates the expression of LYPD1 via an m 6 A-dependent manner in HCC cells. Our findings enrich the landscape of m 6 A-modulated tumor malignancy, and provide new insights into potential biomarkers and therapeutic targets of HCC treatment.

Hepatocellular carcinoma (HCC) is a highly heterogeneous, multigene-driven malignant tumor. Long chain acyl-CoA synthetase 4 (ACSL4), an enzyme has pivotal roles in arachidonic acid (AA) metabolism. However, its function and the underlying molecular mechanisms in HCC are still not fully elucidated. Here, we identified ACSL4 as a novel marker for AFP high subtype HCC through transcriptome profiling. ACSL4 was frequently upregulated in HCC samples and associated with poor prognosis. Functionally, ACSL4 knockdown resulted in decreased cell growth, whereas ectopic ACSL4 expression facilitated tumor formation in vitro and in vivo. Mechanistically, ACSL4 stabilized the oncoprotein c-Myc through ubiquitin–proteasome system in an ERK/FBW7-dependent manner. Cell growth ability mediated by ACSL4 elevation was partly attenuated by c-Myc depletion using siRNA or its inhibitor 10058-F4. In contrast, the effects of ACSL4 silencing were partially reversed by c-Myc overexpression via FBW7 knockdown. Clinically, ACSL4 expression was positively correlated with c-Myc in HCC. In conclusion, ACSL4 is a novel marker for AFP high subtype HCC. Our data uncovered a new mechanism by which ACSL4 promotes HCC progression via c-Myc stability mediated by ERK/FBW7/c-Myc axis and could be a valuable prognostic biomarker and a potential therapeutic target in HCC.

Liver transplantation is the only effective method for end-stage liver disease; however, liver ischemia reperfusion injury (IRI) seriously affects donor liver function after liver transplantation. IRI is a pathophysiological process in which organ damage is aggravated after the blood flow and oxygen supply of ischemic organ tissues are restored. It combines the two stages of hypoxic cell stress triggered by ischemia and inflammation-mediated reperfusion injury. Herein, we studied the protective effect and mechanism of the anti-T cell Ig and mucin domain (TIM1) monoclonal antibody, RMT1-10, on hepatic cell injury induced by IRI. First, a liver IRI model was established in vivo. HE, TEM, and Tunel were used to detect liver tissue injury, changes in the liver ultrastructure and liver cell apoptosis, respectively. ELISA were performed to determine the levels of ALT, AST, MDA, GSH, and related inflammatory factors. We found that RMT1-10 could significantly reduce liver injury. Flow cytometry results showed that the number of TIM1 + regulatory B cells (Bregs) in the IRI liver increased briefly, while pretreatment with RMT1-10 could increase the number of TIM1 + Bregs and interleukin-10 (IL-10) secretion in liver IRI model mice, thus playing a protective role in liver reperfusion. When Anti-CD20 was used to remove B cells, RMT1-10 had a reduced effect on liver IRI. Previous data showed that the number of T helper 1 cells (Th1:CD4 + ; CD8 + ) increased significantly after IRI. RMT1-10 inhibited Th1 cells; however, it significantly activated regulatory T cells. Sequencing analysis showed that RMT1-10 could significantly downregulate the expression of nuclear factor-kappa B (NF-κB) pathway-related genes induced by IRI. These results suggested that RMT1-10 could promote the maturation of B cells through an atypical NF-κB pathway, thereby increasing the number of TIM1 + Bregs and associated IL-10 secretion to regulate the inflammatory response, thereby protecting against liver IRI.

Long non-coding RNA HOTAIR exerts regulatory functions in various biological processes in cancer cells, such as proliferation, apoptosis, mobility, and invasion. We previously found that HOX transcript antisense RNA (HOTAIR) is a negative prognostic factor and exhibits oncogenic activity in hepatocellular carcinoma (HCC). In this study, we aimed to investigate the role and molecular mechanism of HOTAIR in promoting HCC cell migration and invasion. Firstly, we profiled its gene expression pattern by microarray analysis of HOTAIR loss in Bel-7402 HCC cell line. The results showed that 129 genes were significantly down-regulated, while 167 genes were significantly up-regulated (fold change >2, p < 0.05). Bioinformatics analysis indicated that RNA binding proteins were involved in this biological process. HOTAIR suppression using RNAi strategy with HepG2 and Bel-7402 cells increased the mRNA and protein expression levels of RNA binding motif protein 38 (RBM38). Moreover, the expression levels of RBM38 in HCC specimens were significantly lower than paired adjacent noncancerous tissues. In addition, knockdown of HOTAIR resulted in a decrease of cell migration and invasion, which could be specifically rescued by down-regulation of RBM38. Taken together, HOTAIR could promote migration and invasion of HCC cells by inhibiting RBM38, which indicated critical roles of HOTAIR and RBM38 in HCC progression.

It has been reported that long non-coding RNA PANDA was disregulated in varieties types of tumor, but its expression level and biological role in hepatocellular carcinoma (HCC) remains contradictory. We detected PANDA expression in two independent cohorts (48 HCC patients following liver transplantation and 84 HCC patients following liver resection), and found that PANDA was down-regulated in HCC. Thereafter we explored its function in cancer biology by inversing its low expression. Surprisingly, overexpression of PANDA promoted HCC proliferation and carcinogenesis in vitro and in vivo . Mechanistically, PANDA repressed transcriptional activity of senescence associated inflammatory factor IL8, which leaded to inhibition of cellular senescence. Therefore, our research help to better understand the complex role of PANDA in HCC, and suggest more thoughtful strategies should be applied before it can be treated as a potential therapeutic target.

Liver cancer is a significant global health challenge, with hepatocellular carcinoma (HCC) being the most prevalent form, characterized by high incidence and mortality rates. Despite advances in targeted therapies and immunotherapies, the prognosis for advanced liver cancer remains poor. This underscores the urgent need for a deeper understanding of the molecular mechanisms underlying HCC to enable early detection and the development of novel therapeutic strategies. Post-translational modifications (PTMs) are crucial regulatory mechanisms in cellular biology, affecting protein functionality, interactions, and localization. These modifications, including phosphorylation, acetylation, methylation, ubiquitination, and glycosylation, occur after protein synthesis and play vital roles in various cellular processes. Recent advances in proteomics and molecular biology have highlighted the complex networks of PTMs, emphasizing their critical role in maintaining cellular homeostasis and disease pathogenesis. Dysregulation of PTMs has been associated with several malignant cellular processes in HCC, such as altered cell proliferation, migration, immune evasion, and metabolic reprogramming, contributing to tumor growth and metastasis. This review aims to provide a comprehensive understanding of the pathological mechanisms and clinical implications of various PTMs in liver cancer. By exploring the multifaceted interactions of PTMs and their impact on liver cancer progression, we highlight the potential of PTMs as biomarkers and therapeutic targets. The significance of this review lies in its potential to inform the development of novel therapeutic approaches and improve prognostic tools for early intervention in the fight against liver cancer.

Interleukin enhancer binding factor 2 (ILF2), a transcription factor, regulates cell growth by inhibiting the stabilization of mRNA. Currently, its role has gained recognition as a factor in the tumorigenic process. However, until now, little has been known about the detailed role ILF2 plays in hepatocellular carcinoma (HCC). In this study, we investigated the expression levels of ILF2 in HCC tissue with Western blot and immunohistochemical assays. To examine the effect of ILF2 on liver cancer cell growth and apoptosis, small interfering RNAs (siRNAs) targeting ILF2 were recombined to create lentiviral overexpression vectors. Our results showed higher expression levels of ILF2 mRNA and ILF2 protein in HCC tissue compared with matched peritumoral tissue. Expression of ILF2 may regulate cell growth and apoptosis in liver cancer cells via regulation of B-cell lymphoma 2 (Bcl-2), Bcl-2 related ovarian killer (Bok), Bcl-2-associated X protein (BAX), and cellular inhibitor of apoptosis 1 (cIAP1). Moreover, we inoculated nude mice with liver cancer cells to investigate the effect of ILF2 on tumorigenesis in vivo. As expected, a rapid growth was observed in cancer cells inoculated with a lentiviral vector coding Flag-ILF2 (Lenti-ILF2) compared with the control cells. Hence, these results promote a better understanding of ILF2’s potential role as a therapeutic target in HCC.

Background: Hepatocellular carcinoma (HCC), a highly aggressive malignancy with poor prognosis, is characterized by hyperactivation of the epidermal growth factor receptor (EGFR) signaling pathway. Glutaminase (GLS) is commonly overexpressed in numerous malignant tumors and acts as an oncogene to support cell growth and tumor progression, making it a target for cancer treatment. This study aimed to elucidate the underlying mechanisms of EGFR activation in driving glutaminolysis reprogramming and conferring ferroptosis resistance in HCC. Methods: Untargeted metabolomics, stable isotope-assisted metabolomic analysis, and RNA sequencing analysis were utilized to elucidate the mechanisms underlying glutaminolysis reprogramming upon EGFR activation. Immunoprecipitation, RNA pulldown, and dual-luciferase reporter assays were employed to examine the regulatory role of Wilms’ tumor 1-associated protein (WTAP) phosphorylation in GLS alternative splicing. Flow cytometry, cell viability assays, tumor-bearing mouse models, and HCC clinical specimens were used to validate the role of the AKT–WTAP–GLS axis in ferroptosis resistance and tumor progression. Results: Here, we demonstrated that AKT activated by EGFR signaling phosphorylated WTAP S176 and increased WTAP binding to methyltransferase-like protein 3. The enhanced interaction promoted the site-specific N6-methyladenosine (m 6 A) modification of GLS pre-mRNA, which in turn favored the alternative splicing of GLS toward glutaminase C (GAC) over kidney-type glutaminase. This switch led to increased glutamine utilization and glutathione/nicotinamide adenine dinucleotide phosphate (reduced form) biosynthesis, thereby alleviating ferroptosis and promoting tumor growth in mice. In addition, the levels of WTAP pS176 and GAC expression, which were mutually correlated, were positively associated with poor prognosis of patients with HCC. Conclusions: These findings uncover a critical mechanism by which tumor cells counteract ferroptosis by WTAP-mediated GLS alternative splicing under EGFR activation, highlighting the therapeutic potential of targeting the m 6 A-dependent GLS isoform switch in HCC and offering a rationale for the development of combination therapies.

Background Controversy exists regarding the role of PD1 and its ligand PD-L1 in chronic hepatitis B infection. In some studies, persistent HBV infection has been attributed to high levels of PD-1 and PD-L1 expression on HBV-specific T-cells and antigen-presenting cells (APCs) respectively. Other studies revealed that the up-regulation of PD-1 and PD-L1 during an acute inflammation phase is required to offset increasing positive co-stimulatory signals to avoid severe damage by an over-vigorous immune response. Methods Fifteen chronic hepatitis B patients, with inflammatory flare episode, were recruited prospectively. Based on serum HBV-DNA, HBsAg load, and ALT values, inflammatory flare episode were divided into initial, climax, decline and regression phase. Blood sample and liver biopsy tissues from each individual were taken in these 4 phases respectively. Circulating and intra-hepatic PD1 and PD-L1 expression levels were monitored throughout the inflammatory flare episode by flow cytometry and immunostaining and these expression levels were related to the HBV-specific T-cell changes, expression of pro-inflammatory cytokines, HBV-DNA replication and HBV antigen load. Results ]The levels of PD-1 and PD-L1 expressions were significantly up-regulated in the inflammation ascending phase, initial and climax period and in parallel with HBV-specific colon expansion. It showed increasing the level of serum ALT and decreasing the HBV-DNA loads. As the level of inflammation reduced, the circulating and intra-hepatic PD1 and circulating PD-L1 decreased progressively in concordance with serum ALT, HBV-DNA and HBsAg loads decreased except intra-hepatic PD-1 expression. Intra-hepatic PD-L1 expression did not decrease significantly during the regression phase of inflammation compared to that in prior period. The intra-hepatic PD-L1 expression remained relatively on higher level when serum HBV-DNA load and ALT decreased to approximately normal range. Conclusion The relatively high level of intra-hepatic PD-L1 expression during the inflammatory regression period may contribute to constitute an immunosuppressive microenvironment, which facilitate persistent HBV infection via the inhibition of HBV-specific T cell clonal expansion.