BACKGROUND: Cluster of differentiation 8 positive (CD8 + ) T cells play a crucial role in the response against tumors, including hepatocellular carcinoma (HCC), where their dysfunction is commonly observed. While the association between elevated peroxisome proliferator-activated receptor alpha (PPARα) expression in HCC cells and exosomes and unfavorable prognosis in HCC patients is well-established, the underlying biological mechanisms by which PPARα induces CD8 + T cell exhaustion mediated by HCC exosomes remain poorly understood. METHODS: Bioinformatics analyses and dual-luciferase reporter assays were used to investigate the regulation of microRNA-27b-3p ( miR-27b-3p ) and thymocyte selection-associated high mobility group box ( Tox ) by Pparα . In vitro and in vivo experiments were conducted to validate the effects of HCC-derived exosomes, miR-27b-3p overexpression, and Pparα on T cell function. Exosome characterization was confirmed using transmission electron microscopy, Western blotting, and particle size analysis. Exosome tracing was performed using small animal in vivo imaging and confocal microscopy. The expression levels of miR-27b-3p , Pparα , and T cell exhaustion-related molecules ( Tox , Havcr2 , and Pdcd1 ) were detected using quantitative reverse transcription polymerase chain reaction analysis, Western blotting analysis, immunofluorescence staining, and flow cytometry analysis. RESULTS: Pparα expression was significantly increased in HCC and negatively correlated with prognosis. It showed a positive correlation with Tox and a negative correlation with miR-27b-3p . The overexpressed Pparα from HCC cells was delivered to CD8 + T cells via exosomes, which absorbed miR-27b-3p both in vitro and in vivo , acting as "miRNA sponges". Further experiments demonstrated that Pparα can inhibit the negative regulation of Tox mediated by miR-27b-3p through binding to its 3'untranslated regions. CONCLUSIONS HCC-derived exosomes deliver Pparα to T cells and promote CD8 + T cell exhaustion and malignant progression of HCC via the miR-27b-3p /TOX regulatory axis. The mechanisms underlying T-cell exhaustion in HCC can be utilized for the advancement of anticancer therapies.
MicroRNAs/metabolism* ; PPAR alpha/genetics* ; Carcinoma, Hepatocellular/genetics* ; Humans ; Liver Neoplasms/genetics* ; CD8-Positive T-Lymphocytes/immunology* ; Exosomes/metabolism* ; Animals ; Cell Line, Tumor ; Mice ; High Mobility Group Proteins/genetics* ; Male ; T-Cell Exhaustion

This study investigates the effect of glycyrrhetinic acid(GA) combined with doxorubicin(DOX) on apoptosis in HepG2 cells and its possible mechanisms. HepG2 cells were cultured in vitro, and cell viability was assessed using the cell counting kit-8(CCK-8) method. Flow cytometry was used to measure apoptosis levels in HepG2 cells. The cells were divided into the following groups: control group(0 μmol·L~(-1)), DOX group(2 μmol·L~(-1)), GA group(150 μmol·L~(-1)), and DOX + GA combination group(2 μmol·L~(-1) DOX + 150 μmol·L~(-1) GA), with treatments given for 24 hours. The colocalization level between the endoplasmic reticulum(ER) and mitochondria was assessed by colocalization fluorescence imaging. Fluorescence probes were used to measure the Ca~(2+) content in the ER and mitochondria. The qRT-PCR and Western blot were used to determine the mRNA and protein expression of sirtuin-3(SIRT3). Co-immunoprecipitation(CO-IP) was applied to investigate the interactions between voltage-dependent anion channel 1(VDAC1) and SIRT3, as well as between VDAC1, glucose-regulated protein 75(GRP75), and inositol 1,4,5-trisphosphate receptor(IP3R). The results showed that the combination of DOX and GA promoted apoptosis in HepG2 liver cancer cells. The colocalization level between the ER and mitochondria was significantly reduced, the Ca~(2+) content in the ER was significantly increased, and the Ca~(2+) content in the mitochondria was significantly decreased. The relative expression of VDAC1, GRP75, and IP3R was significantly reduced, and interactions between VDAC1, GRP75, and IP3R were observed. SIRT3 mRNA and protein expression levels were significantly increased, and an interaction between SIRT3 and VDAC1 was detected. The acetylation level of VDAC1 was significantly decreased. In conclusion, GA combined with DOX induces apoptosis in HepG2 cells by mediating the deacetylation of VDAC1 through SIRT3, weakening the interactions among VDAC1, GRP75, and IP3R. This regulates the formation of endoplasmic reticulum-mitochondrial membrane domains(ERMMDs), affects Ca~(2+) transport between the ER and mitochondria, and ultimately triggers cell apoptosis.
Humans ; Apoptosis/drug effects* ; Hep G2 Cells ; Glycyrrhetinic Acid/pharmacology* ; Doxorubicin/pharmacology* ; Liver Neoplasms/genetics* ; Carcinoma, Hepatocellular/physiopathology* ; Mitochondria/metabolism* ; Endoplasmic Reticulum/metabolism* ; Cell Survival/drug effects* ; Membrane Proteins/genetics*

Objective To explore the clinical and immunological significance of CCDC97 in hepatocellular carcinoma (HCC). Methods Clinical data and RNA sequencing results from HCC patients were retrieved from TCGA and ICGC databases. Bioinformatics analysis and in vitro experiments were performed to investigate the role of CCDC97 in HCC. Results The expression level of CCDC97 was elevated in HCC patients and HCC cells, closely associated with pathological features and prognosis. CCDC97 was identified as a novel prognostic biomarker. It is linked to the spliceosome pathway, which is significantly active in tumors and potentially promotes carcinogenesis. CCDC97 is also highly expressed in various immune cells and is associated with microenvironment. Furthermore, knocking down CCDC97 in vitro suppressed cell migration, invasion, and proliferation. Conclusion CCDC97 plays a critical role in HCC progression and the immune microenvironment, making it a potential target for prognosis and therapeutic intervention.
Humans ; Carcinoma, Hepatocellular/metabolism* ; Liver Neoplasms/metabolism* ; Tumor Microenvironment/genetics* ; Cell Movement/genetics* ; Cell Proliferation ; Prognosis ; Cell Line, Tumor ; Gene Expression Regulation, Neoplastic ; Biomarkers, Tumor/genetics* ; Male

Objective To investigate the mechanism by which miR-148a affects M2 macrophage polarization and inhibits liver cancer cell proliferation through Wnt3a/β-catenin. Methods The mRNA expression levels of miR-148a, CD206 and interleukin-10 (IL-10) in tumor tissues and adjacent non-tumor liver tissues of 84 patients with liver cancer were detected by real-time quantitative PCR. THP-1 cells were separated into blank group (conventional culture), M2 group (200 nmol/L phorbol ester, 20 ng/mL IL-4, 20 ng/mL IL-13), M2 combined with negative control (miR-NC) group (transfected with miR-NC on the basis of M2 group), M2 combined with miR-148a mimics (transfected with miR-148a mimics on the basis of M2 group) group, M2 combined with miR-148a mimics combined with Wnt3a (treated with 100 μg/L Wnt3a on top of M2 combined with miR-148a mimics group) group. The proliferation of HuH7 cells was detected by CCK-8 and EdU methods. Apoptosis and M2 macrophage marker CD206 was detected by flow cytometry. The level of IL-10 in cell supernatant was detected by chemiluminescence method; The mRNA levels of miR-148a, CD206 and IL-10 were detected by real-time quantitative PCR. The protein levels of Wnt3a and β-catenin were detected by Western blot. Results The expressions of CD206, IL-10 mRNA, Wnt3a and β-catenin in tumor tissue were higher than those in non-tumor liver tissues, and the miR-148a level was decreased. The mRNA expression of M2 macrophage markers CD206 and IL-10 were significantly increased. Compared with the blank group, the OD450 value, EdU positive rate, the mRNA expressions of CD206 and IL-10, the level of IL-10 in the supernatant, and the expressions of Wnt3a and β-catenin were increased in M2 group, while the apoptotic rate and miR-148a level were decreased. Compared with M2 group and M2 combined with miR-NC group, the OD₄₅₀ value, EdU positive rate, the mRNA expressions of CD206 and IL-10, the level of IL-10 in the supernatant, and the expressions of Wnt3a and β-catenin were decreased in M2 combined with miR-148a mimics group, while the apoptotic rate and miR-148a level were increased. Wnt3a reversed the inhibitory effect of miR-148a overexpression on the proliferation of liver cancer cells. Conclusion Overexpression of miR-148a inhibits M2 polarization of macrophages and prevents the proliferation of liver cancer cells, which may be related to the inhibition of the Wnt3a/β-catenin pathway.
Humans ; MicroRNAs/metabolism* ; Wnt3A Protein/metabolism* ; Liver Neoplasms/metabolism* ; Cell Proliferation/genetics* ; beta Catenin/genetics* ; Macrophages/metabolism* ; Interleukin-10/metabolism* ; Apoptosis/genetics* ; Cell Line, Tumor ; Female ; Male ; Mannose Receptor ; Lectins, C-Type/metabolism* ; Mannose-Binding Lectins/metabolism* ; Middle Aged ; Receptors, Cell Surface/metabolism*

OBJECTIVES: To investigate the association of NUF2 expression with tumor prognosis and its regulatory role in tumor microenvironment. METHODS: We analyzed NUF2 expression, its prognostic value, and is immune-related functions across different cancer types using datasets from the Human Protein Atlas (HPA), TCGA, GTEx, CCLE, and TIMER. RT-qPCR, Western blotting, and immunohistochemistry were used to detect NUF2 expression in liver cancer cell lines and tissue and blood samples from patients with liver cancer. GO, KEGG, and GSEA analyses were conducted to explore the molecular mechanisms of NUF2 and its related genes, and a competitive endogenous RNA (ceRNA) network for NUF2 in liver cancer was constructed. RESULTS: NUF2 expression was upregulated in the tumor tissues of 27 cancers and was associated with clinical stages in several cancers. High NUF2 expressions were correlated with poor overall survival, disease-specific survival, progression-free survival, and disease-free survival of cancer patients. NUF2 expression levels were positively correlated with tumor mutational burden, microsatellite instability, infiltrating immune cells, immune cell marker genes and immune checkpoint genes in different cancers. RT-qPCR, Western blotting, and immunohistochemistry confirmed that NUF2 expression was upregulated in liver cancer cell lines and tumor tissues and blood samples of liver cancer patients, and was decreased significantly after operation. GO, KEGG and GSEA analyses indicated that NUF2 was involved in chromosome segregation and cell cycle and was associated with glycine, serine and threonine metabolism. CONCLUSIONS NUF2 expression is upregulated in 27 cancers and is associated with clinical stage and poor prognosis in some malignancies. NUF2 expression is closely correlated with immune cell infiltration in different cancers, suggesting its potential value for predicting immunotherapy response in these cancers.
Humans ; Prognosis ; Immunotherapy ; Tumor Microenvironment ; Liver Neoplasms/metabolism* ; Cell Line, Tumor ; Neoplasms/genetics* ; Gene Expression Regulation, Neoplastic ; Biomarkers, Tumor/genetics*

OBJECTIVES: To investigate the clinical significance of SLC1A5 overexpression in pan-cancer and its mechanism for promoting hepatocellular carcinoma (HCC) progression. METHODS: We analyzed the correlation of SLC1A5 expression with clinical stage, lymph node metastasis and prognosis in pan-cancer using TCGA and ICGC datasets and explored its association with immune cell infiltration using EPIC, CIBERSORT, and TIMER algorithms. In HCC cell lines, the effects of lentivirus-mediated SLC1A5 overexpression or RNA interference on cell proliferation were examined using CCK-8 assay, and the growth of HCC cell xenografts overexpressing SLC1A5 was observed in nude mice. The effects of SLC1A5 overexpression or silencing in HCC cells on macrophage polarization were evaluated in a cell co-culture system. RESULTS: SLC1A5 was mainly localized on cell membrane and was highly expressed in most cancers in association with clinical stage, lymph node metastasis and poor prognosis. SLC1A5 expression was positively correlated with immunity score in 13 cancer types, especially in low-grade glioma (LGG), LIHC and thyroid cancer. SLC1A5 was positively correlated with macrophage infiltration level in LGG and LIHC but negatively correlated with macrophage infiltration in 5 cancers including lung squamous carcinoma, pancreatic carcinoma, and gastric carcinoma. Patients with SLC1A5 overexpression and high level of M2 macrophage infiltration had the worst survival outcomes. SLC1A5 was correlated with immunosuppression-related genes, cytokines, and cytokine receptors, which was the most obvious in LGG and LIHC. SLC1A5 was highly expressed in different HCC cell lines, and its overexpression promoted HCC cell proliferation both in vitro and in nude mice. In the cell co-culture experiment, SLC1A5 was positively correlated with the molecular markers of M2 polarization of macrophages, and its overexpression strongly promoted M2 polarization of the macrophages and inhibited T cell secretion of IFN-γ. CONCLUSIONS SLC1A5 expression level is correlated with clinical stage, lymph node metastasis, prognosis, and immune cell infiltration in most cancers, and its overexpression promotes HCC progression by inhibiting T-cell function via promoting M2 polarization of macrophages.
Humans ; Carcinoma, Hepatocellular/metabolism* ; Liver Neoplasms/metabolism* ; Animals ; Macrophages/cytology* ; Disease Progression ; Cell Line, Tumor ; Mice ; Amino Acid Transport System ASC/genetics* ; Cell Proliferation ; Lymphatic Metastasis ; Mice, Nude ; Prognosis ; Minor Histocompatibility Antigens

OBJECTIVES: To investigate the mechanism by which transforming growth factor‑β (TGF‑β) regulates major histocompatibility complex class I (MHC-I) expression in hepatocellular carcinoma (HCC) cells and its role in immune evasion of HCC. METHODS: HCC cells treated with TGF‑β alone or in combination with SB-431542 (a TGF-β type I receptor inhibitor) were examined for changes in MHC-I expression using RT-qPCR and Western blotting. A RNA interference experiment was used to explore the role of miR-23a-3p/IRF1 signaling in TGF‑β‑mediated regulation of MHC-I. HCC cells with different treatments were co-cultured with human peripheral blood mononuclear cells (PBMCs), and the changes in HCC cell proliferation was assessed using CCK-8 and colony formation assays. T-cell cytotoxicity in the co-culture systems was assessed with lactate dehydrogenase (LDH) release and JC-1 mitochondrial membrane potential assays, and T-cell activation was evaluated by flow cytometric analysis of CD69 cells and ELISA for TNF-α secretion. RESULTS: TGF‑β treatment significantly suppressed MHC-I expression in HCC cells and reduced T-cell activation, leading to increased tumor cell proliferation and decreased HCC cell death in the co-culture systems. Mechanistically, TGF-β upregulated miR-23a-3p, which directly targeted IRF1 to inhibit MHC-I transcription. Overexpression of miR-23a-3p phenocopied TGF‑β‑induced suppression of IRF1 and MHC-I. CONCLUSIONS We reveal a novel immune escape mechanism of HCC, in which TGF‑β attenuates T cell-mediated antitumor immunity by suppressing MHC-I expression through the miR-23a-3p/IRF1 signaling axis.
Humans ; MicroRNAs/genetics* ; Carcinoma, Hepatocellular/metabolism* ; Liver Neoplasms/metabolism* ; Interferon Regulatory Factor-1/metabolism* ; Transforming Growth Factor beta/metabolism* ; Signal Transduction ; Histocompatibility Antigens Class I/metabolism* ; Cell Line, Tumor ; Tumor Escape ; Coculture Techniques

OBJECTIVES: To investigate the role of long noncoding RNA (lncRNA) HClnc1 in regulating proliferation, invasion, and migration of hepatocellular carcinoma (HCC) cells and the regulatory mechanism. METHODS: HClnc1 expression levels in liver cancer tissues were analyzed using data from the TCGA database. BrdU incorporation, plate cloning, and transwell assays were employed to examine the effects of HClnc1 silencing/overexpression and/or ODC1 silencing on proliferation, invasion, and migration of liver cancer cells. The effects of HClnc1 silencing on ODC1 protein and mRNA expression in the liver cancer cells were analyzed using qRT-PCR and Western blotting. The activity of ODC1 promoter was analyzed using a dual luciferase reporter gene assay. Pull-down experiment, mass spectrometry analysis, and chromatin immunoprecipitation (ChIP) assay were used for identification of HClnc1-binding proteins and their interactions. Protein interactions with the ODC1 promoter region and their binding efficiencies were investigated using RNA interference and ChIP analysis. RESULTS: HClnc1 was significantly overexpressed in HCC tissues. In liver cancer cells, HClnc1 silencing significantly inhibited cell proliferation, invasion, and migration, while HClnc1 overexpression promoted these behaviors. ODC1 silencing also suppressed malignant behaviors of liver cancer cells, and counteracted the effects of HClnc1 overexpression. Interference of HClnc1 obviously inhibited ODC1 promoter activity. RBBP5 and KAT2B proteins were identified to bind simultaneously with HClnc1. HClnc1 overexpression upregulated ODC1 protein expression, while interference of RBBP5 or KAT2B downregulated ODC1 protein expression and blocked HClnc1-induced upregulation of ODC1 protein. Both RBBP5 and KAT2B could directly bind to ODC1 promoter region; knocking out KAT2B or RBBP5 reduced the binding efficiency, while knocking out HClnc1 reduced the binding of both RBBP5 and KAT2B to ODC1 promoter region. CONCLUSIONS By targeting the RBBP5/KAT2B epigenetic modification complex, HClnc1 increases ODC1 promoter activity to enhance ODC1 transcription and promote the proliferation and migration of liver cancer cells.
Humans ; Cell Proliferation ; RNA, Long Noncoding/genetics* ; Cell Movement ; Liver Neoplasms/metabolism* ; Cell Line, Tumor ; Carcinoma, Hepatocellular/genetics* ; Promoter Regions, Genetic ; Gene Expression Regulation, Neoplastic

OBJECTIVES: To investigate the expression of parathyroid hormone-like hormone (PTHLH) in hepatocellular carcinoma (HCC) and analyze its correlation with clinical prognosis, its regulatory effects on HCC cell behaviors, and the signaling pathways mediating its effects. METHODS: We analyzed the differential expression of PTHLH in HCC and adjacent tissues and its association with patient prognosis based on data from TCGA and GEO databases and from 70 HCC patients treated in our hospital. The effects of PTHLH knockdown and overexpression on proliferation, migration, and invasion of cultured HCC cells were investigated using CCK-8 assay, colony formation assay, Transwell migration and invasion assays, and the signaling pathways activated by PTHLH were detected using Western blotting. RESULTS: TCGA and GEO database analysis showed significant overexpression of PTHLH mRNA in HCC tissues, which was associated with poor prognosis of the patients (P<0.05). High PTHLH mRNA expression was a probable independent prognostic risk factor for HCC (P<0.05). In the clinical samples, PTHLH mRNA and protein expressions were significantly higher in HCC tissues than in the adjacent tissues (P<0.001 or 0.01). Univariate and multivariate Cox regression analyses suggested that high PTHLH mRNA expression was an independent risk factor to affect postoperative disease-free survival of HCC patients (P<0.05). The prognostic prediction model based on PTHLH mRNA expression showed an improved accuracy for predicting the risk of postoperative recurrence in HCC patients. In cultured HCC cells, PTHLH overexpression significantly promoted cell proliferation, colony formation, migration and invasion, and caused activation of the ERK/JNK signaling pathway in Huh7 and Hep3B cells. CONCLUSIONS High PTHLH expression promotes HCC progression and is associated with poor patient prognosis. Its pro-tumor effects may be mediated by activation of the ERK/JNK signaling pathway.
Humans ; Carcinoma, Hepatocellular/metabolism* ; Liver Neoplasms/metabolism* ; Prognosis ; Cell Proliferation ; Parathyroid Hormone-Related Protein/genetics* ; Cell Line, Tumor ; Cell Movement ; Disease Progression ; Signal Transduction ; Male ; RNA, Messenger/genetics* ; Female

Deactivation of the mitochondrial pyruvate dehydrogenase complex (PDC) is important for the metabolic switching of cancer cell from oxidative phosphorylation to aerobic glycolysis. Studies examining PDC activity regulation have mainly focused on the phosphorylation of pyruvate dehydrogenase (E1), leaving other post-translational modifications largely unexplored. Here, we demonstrate that the acetylation of Lys 488 of pyruvate dehydrogenase complex component X (PDHX) commonly occurs in hepatocellular carcinoma, disrupting PDC assembly and contributing to lactate-driven epigenetic control of gene expression. PDHX, an E3-binding protein in the PDC, is acetylated by the p300 at Lys 488, impeding the interaction between PDHX and dihydrolipoyl transacetylase (E2), thereby disrupting PDC assembly to inhibit its activation. PDC disruption results in the conversion of most glucose to lactate, contributing to the aerobic glycolysis and H3K56 lactylation-mediated gene expression, facilitating tumor progression. These findings highlight a previously unrecognized role of PDHX acetylation in regulating PDC assembly and activity, linking PDHX Lys 488 acetylation and histone lactylation during hepatocellular carcinoma progression and providing a potential biomarker and therapeutic target for further development.
Humans ; Acetylation ; Carcinoma, Hepatocellular/genetics* ; Liver Neoplasms/genetics* ; Pyruvate Dehydrogenase Complex/genetics* ; Gene Expression Regulation, Neoplastic ; Animals ; Mice ; Cell Line, Tumor ; Protein Processing, Post-Translational ; Histones/metabolism* ; Disease Progression