Expression In Hepatocellular Carcinoma Cells Research Articles

Quercetin inhibits endothelial & hepatocellular carcinoma cell crosstalk via reducing extracellular vesicle-mediated VEGFR2 mRNA transfer.

This study aims to investigate the regulatory effects of quercetin extracellular vesicles (EVs)-mediated expression of vascular endothelial growth factor receptor 2 (VEGFR2) in hepatocellular carcinoma (HCC)-derived circulating tumor cells (CTCs) and the underlying mechanisms. CTCs were isolated from patients with pathologically diagnosed HCC, with VEGFR2 expression visualized by fluorescence in situ hybridization (FISH). The human HCC cell line Huh-7 and SK-HEP-1 were used for in vitro studies to assess EVs uptake, VEGFR2 mRNA transfer, invasion, migration, cancer stem cell (CSC) properties, and VEGF secretion. Results showed that VEGFR2 mRNA was commonly expressed in HCC-CTCs, with a higher incidence in biphenotypic CTCs. Its expression was limited in HCC cell lines, but present in certain liver cells. In vitro experiments confirmed that VEGFR2 mRNA could be transferred to HCC cells via EVs from primary tumor endothelial cells (PTECs), which was impaired by quercetin treatment. Quercetin significantly reduced VEGFR2 mRNA and protein expression in HCC cells, weakened their invasive and metastatic capacities, and diminished VEGFR2-mediated CSC properties. In vivo, quercetin reduced VEGF secretion, impaired angiogenesis, slowed tumor growth, and decreased the number and proportion of VEGFR2-positive CTCs. In summary, VEGFR2 mRNA is present in HCC-CTCs, potentially sourced from PTECs-derived EVs. Quercetin effectively inhibits VEGFR2 expression, impacting HCC cell invasion, metastasis, and CSC characteristics. Besides, it reduces VEGFR2-positive CTCs in vivo. These effects support its therapeutic potential in HCC treatment by targeting the angiogenesis and tumor dissemination pathway.

Cinobufotalin inhibits proliferation, migration and invasion in hepatocellular carcinoma by triggering NOX4/NLRP3/GSDMD-dependent pyroptosis

IntroductionPyroptosis is an inflammatory form of programmed cell death that plays a significant role in tumorigenesis. Cinobufotalin (CB), a bufadienolide extracted from toad venom, is associated with antitumor effects in various cancers, including liver cancer. However, the role of CB in pyroptosis and its underlying mechanisms have not been well characterized.MethodsMTT, Colony formation, EdU, Wound healing and Transwell migration and invasion assays were applied to determine the effects of CB on the proliferation, migration, and invasion ability of hepatocellular carcinoma (HCC) cells in vitro. The subcutaneous xenograft mouse model and pulmonary metastasis model were used to evaluate the effect of CB on HCC cells in vivo. PCR, western blot, immunohistochemistry, immunofluorescence, and ELISA were used to verify the expression of proliferation, migration, pyroptosis, and inflammation related molecules after CB treatment. Using si-RNA and inhibitors to interfere with NOX4 and HLRP3 expression to validate the key signaling pathways of pyroptosis induced by CB treatment.ResultsIn vivo experiments using nude mice with xenografted HCC cells and in vitro experiments with HCC cell lines demonstrated that CB treatment significantly inhibited the proliferation, migration, and invasiveness of HCC cells. CB treatment also showed dose-dependent activation of the NLRP3 inflammasome complex in HCC cells, leading to gasdermin D-induced pyroptosis. However, these effects were abrogated via the pretreatment of HCC cells with VX-765, a caspase-1 inhibitor. Additionally, CB increased the production of reactive oxygen species (ROS) and H₂O₂, along with upregulating NOX4 protein expression in HCC cells. Conversely, NOX4 silencing or pretreatment with VAS2870 (an NOX4 inhibitor) or NAC (an ROS scavenger) suppressed the activation of the NLRP3 inflammasome complex and pyroptosis in CB-treated HCC cells.DiscussionOur study demonstrated that CB suppressed the proliferation, migration, and invasiveness of HCC cells by inducing pyroptosis through the activation of the NOX4/NLRP3/GSDMD signaling pathway. Therefore, our results suggest that CB is a promising therapeutic agent for HCC.

N6-Methyladenosine (m6A) modification activates serine synthesis pathway to mediate therapeutic resistance in liver cancer

Metabolic adaptation serves as a significant driving force for cancer growth and poses a substantial obstacle for cancer therapies. Herein, we unravelled the role of m6A -mediated serine synthesis pathway regulation in both hepatocellular carcinoma (HCC) development and therapeutic resistance. We demonstrated that the highly specific m6A inhibitor (STM2457) treatment effectively inhibited HCC cell line growth and suppressed spontaneous HCC formation in mice driven by liver specific Tp53 knockout and Myc overexpression. Using GLORI-seq, we delineated a single-base resolution m6A landscape in human HCC cell lines. Interestingly, we identified three core enzymes in the serine synthesis pathway (PHGDH, PSAT1, and PSPH) as novel targets of METTL3-mediated m6A modification. In these SSP genes, m6A modification recruited IGF2BP3 reader to stabilize their mRNA transcripts, thereby enhancing their mRNA and protein expression in HCC cells. Most importantly, our GLORI-seq data revealed that sorafenib-resistant HCC cells elevated m6A modification in SSP genes to promote protein expression and antioxidant production. STM2457 treatment attenuated the serine synthesis pathway, induced oxidative stress, and sensitized HCC cells to sorafenib and lenvatinib treatments. In conclusion, our findings suggest that targeting m6A could be a potential therapeutic strategy for HCC treatment.

Long non-coding RNA LNC-POTEM-4 promotes HCC progression via the LNC-POTEM-4/miR-149-5p/Wnt4 signaling axis

Information on the potential role of the long non-coding RNA LNC-POTEM-4 in cancer progression is limited. Our preliminary study found that LNC-POTEM-4 was overexpressed in hepatocellular carcinoma (HCC) tissues, which led us to further investigate the biological function and molecular mechanism of LNC-POTEM-4 in HCC development. LNC-POTEM-4 expression in HCC tissues was examined using transcriptome sequencing and quantitative reverse transcription PCR. The relationships between LNC-POTEM-4 and the stage and prognosis of HCC in patient data from the TCGA database were analyzed. The effects of LNC-POTEM-4 on proliferation, invasion/migration, and epithelial-mesenchymal transition marker expression in HCC cells were evaluated in vitro using gain- and loss-of-function assays, while its effects on tumor growth and metastasis were explored through animal experiments. A LNC-POTEM-4/microRNA (miR)-149-5p/Wnt4 regulatory signaling axis was identified using bioinformatics analysis, and dual luciferase reporter, RNA immunoprecipitation, and RNA pull-down assays. Co-transfection of LNC-POTEM-4 and Wnt4 expression plasmids was employed to confirm the new signaling pathway. We found that LNC-POTEM-4 was overexpressed in HCC tissues and was linked to poor staging and prognosis. LNC-POTEM-4 promoted proliferation, invasion, migration, and the epithelial-mesenchymal transition of HCC cells in vitro. Silencing of LNC-POTEM-4 inhibited HCC growth and distant metastasis in vivo. Mechanically, LNC-POTEM-4 was found to function as a competitive endogenous RNA, upregulating Wnt4 by sponging miR-149-5p to promote HCC progression. Wnt4 overexpression may have counteracted the tumor-inhibition effect of LNC-POTEM-4 silencing. In conclusion, LNC-POTEM-4 upregulated Wnt4 to activate the Wnt signaling pathway and stimulate the malignancy tendency of HCC by sponging miR-149-5p, providing a prospective target for the detection and therapy of HCC. However, the effects of LNC-POTEM-4 on the miR-149-5p/Wnt4 signaling axis should be further studied in animal experiments.

AURKB targets DHX9 to promote hepatocellular carcinoma progression via PI3K/AKT/mTOR pathway.

Aurora kinase B (AURKB) is known to play a carcinogenic role in a variety of cancers, but its underlying mechanism in liver cancer is unknown. This study aimed to investigate the role of AURKB in hepatocellular carcinoma (HCC) and its underlying molecular mechanism. Bioinformatics analysis revealed that AURKB was significantly overexpressed in HCC tissues and cell lines, and its high expression was associated with a poorer prognosis in HCC patients. Furthermore, downregulation of AURKB inhibited HCC cell proliferation, migration, and invasion, induced apoptosis, and caused cell cycle arrest. Moreover, AURKB downregulation also inhibited lung metastasis of HCC. AURKB interacted withDExH-Box helicase 9(DHX9) and targeted its expression in HCC cells. Rescue experiments further demonstrated that AURKB targeting DHX9 promoted HCC progression through the PI3K/AKT/mTOR pathway. Our results suggest that AURKB is significantly highly expressed in HCC and correlates with patient prognosis. Targeting DHX9 with AURKB promotes HCC progression via the PI3K/AKT/mTOR pathway.

Cancer-associated fibroblasts-derived exosomal ZNF250 promotes the proliferation, migration, invasion, and immune escape of hepatocellular carcinoma cells by transcriptionally activating PD-L1.

Hepatocellular carcinoma (HCC) is a lethal form of liver cancer, and the tumor microenvironment, particularly cancer-associated fibroblasts (CAFs), plays a critical role in its progression. This study aimed to elucidate the mechanism by which CAF-derived exosomes regulate the development of HCC. The study employed quantitative real-time polymerase chain reaction for mRNA expression analysis and western blot analysis for protein expression detection. Chromatin immunoprecipitation assay and dual-luciferase reporter assay were performed to investigate the relationship between zinc finger protein 250 (ZNF250) and programmed cell death 1 ligand 1 (PD-L1). Transmission electron microscopy and western blot analysis were used to characterize the isolated exosomes. The transferability of CAF-derived exosomes and normal fibroblasts (NFs)-derived exosomes into HCC cells was analyzed using a green fluorescent labeling dye PKH67. Cell proliferation was assessed via a 5-Ethynyl-2'-deoxyuridine assay, while Transwell assays were conducted to evaluate cell migration and invasion. Flow cytometry was performed to measure cell apoptosis, while enzyme-linked immunosorbent assays were used to assess the levels of tumor necrosis factor-α and perforin. Finally, a xenograft mouse model was constructed to examine the effects of exosomes derived from ZNF250-deficient CAFs on the tumor properties of HCC cells. The study revealed increased expression of ZNF250 in HCC tissues and cells, with ZNF250 transcriptionally activating PD-L1 in HCC cells. ZNF250 expression was associated with HbsAg, clinical stage and tumor size of HCC patients. CAF-derived exosomal ZNF250 can regulate PD-L1 expression in HCC cells. Furthermore, exosomes derived from ZNF250-deficient CAFs inhibited the proliferation, migration, invasion, and immune escape of HCC cells by downregulating PD-L1 expression. Moreover, CAF-derived exosomal ZNF250 promoted tumor formation in vivo. These findings provide insights into the role of CAF-derived exosomes in the suppression of HCC development, highlighting the significance of ZNF250 and PD-L1 regulation in tumor progression.

LINC00161 upregulated by M2-like tumor-associated macrophages promotes hepatocellular carcinoma progression by methylating HACE1 promoters.

M2-like tumor-associated macrophages (M2-TAM) played an essential part in hepatocellular carcinoma (HCC) progression. Long intergenic noncoding RNA 00161 (LINC00161), is a long non-coding RNA, that was related to HCC development. However, the relationship between LINC00161 and TAM remains indistinct. HCC cells were cocultured with an M2-like conditioned medium (M2-CM). cell counting kit-8 (CCK-8), plate cloning, cell scratch, and transwell assay evaluated cell biological activities of HCC cells. The interactions among molecules were analyzed by chromatin immunoprecipitation (CHIP), dual-luciferase reporter, and RNA immunoprecipitation (RIP). The methylation status of HECT domain and ankyrin repeat-containing, E3 ubiquitin protein ligase 1 (HACE1) was evaluated using methylation-specific PCR (MSP) and bisulfite sequencing PCR (BSP). The xenograft model was established in vivo using subcutaneous nude mice. Histological analyses were performed using hematoxylin-eosin (HE) staining. The expression of molecules was determined using immunohistochemistry (IHC), western blot and quantitative real-time PCR (qPCR). LINC00161 expression was promoted in HCC. LINC00161 knockdown significantly reduced HCC cell proliferation, migration, and invasion. Additionally, M2-TAM stimulated LINC00161 transcription and expression in HCC cells by secreting hepatocyte growth factor (HGF) to activate the Met/NFκB pathway. LINC00161 suppressed HACE1 expression, and knockdown of LINC00161 decreased the methylation on the HACE1 promoter. Meanwhile, a binding relationship between the enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2) and HACE1 was observed. LINC00161 overexpression increased the binding of EZH2 on the HACE1 promoter region. Furthermore, LINC00161 knockdown suppressed tumor growth in vivo and induced HACE1 expression by inhibiting its methylation. LINC00161, induced by M2-TAM, played a pivotal role in contributing to HCC development by recruiting EZH2 to promote the methylation of HACE1. This underscores the significant involvement of LINC00161 in mediating the progression of HCC.

ZFC3H1 as an Indicator of Poor Prognosis in Hepatocellular Carcinoma: Bioinformatic Analysis and Experimental Verification.

Zinc finger C3H1-type containing (ZFC3H1) might regulate RNA processes. However, research lacks the prognostic value of ZFC3H1 in hepatocellular carcinoma (HCC). The study analyzed ZFC3H1 expression in HCC cells and its correlation with patient prognosis using transcriptomics, immunohistochemistry, and quantitative real-time reverse transcription PCR, as well as single-cell RNA expression data. Additionally, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were used to investigate the potential ZFC3H1-related cellular functions and signaling pathways. The impact of ZFC3H1 expression on the tumor microenvironment and tumor mutational burden (TMB) was assessed using the ESTIMATE algorithm. Cell-based assays, including cell counting kit 8, proliferation, colony formation, cell cycle, wound healing, and Transwell assays, were conducted to evaluate the influence of ZFC3H1 on hepatocellular carcinoma proliferation and migration. ZFC3H1 is upregulated in HCC and linked to tumor progression. High ZFC3H1 expression is a prognostic risk factor for HCC, according to Kaplan-Meier and Cox regression analyses. ESTIMATE analysis suggested that ZFC3H1 reduces immune cell infiltration and increases the TMB. Patients with low ZFC3H1 expression might respond better to immunotherapy. High ZFC3H1 expression is associated with increased half-maximal inhibitory concentration (IC50) of sorafenib. Functional experiments demonstrated that reducing ZFC3H1 expression inhibited HCC cell proliferation and migration. ZFC3H1 is upregulated in HCC, promoting the proliferation and migration of liver cancer cells, impacting the prognosis of HCC patients and the effectiveness of immunotherapy. ZFC3H1 might serve as a therapeutic target and biomarker for HCC.

Curzerene suppresses hepatocellular carcinoma progression through the PI3K/AKT/MTOR pathway.

Hepatocellular carcinoma (HCC) is one of the most aggressive cancers worldwide. Curzerene is a sesquiterpene and component of Curcuma rhizomes and has anti-tumor and anti-inflammatory properties. The study aimed to investigate the effects of curzerene on the malignant phenotypes and tumor growth in HCC. Various concentrations of curzerene were used to treat human HCC cells (Huh7 and HCCLM3). Cell viability, apoptosis, cell cycle, invasion, and migration were detected by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, flow cytometry, Transwell, and wound healing assays. Cell cycle-, apoptosis-, and signaling pathway-related proteins were analyzed by Western blot analysis. A mouse xenograft model was established to analyze the anti-tumor effects of curzerene in vivo. Curzerene repressed the proliferation, invasion, and migration of Huh7 and HCCLM3 cells. Curzerene also induced G2/M cycle arrest and cell apoptosis. Curzerene downregulated the CDK1, cyclin B1, PCNA, Bcl-2, matrix metallopeptidases (MMP)2, and MMP9 protein expression and upregulated the Bax, cleaved caspase3, and cleaved poly ADPribose polymerase protein expression in HCC cells. Curzerene restrained the phosphorylation of PI3K, AKT, and the Mammalian target of rapamycin (mTOR) in Huh7 and HCCLM3 cells. The in vivo data revealed that curzerene inhibited HCC tumor growth and decreased the expression of phosphorylated mTOR in xenograft mouse models. Curzerene inhibited cell malignancy in vitro and tumor growth in vivo in HCC, suggesting that curzerene may be a candidate agent for anti-HCC therapy.

Semaphorin 3C (Sema3C) reshapes stromal microenvironment to promote hepatocellular carcinoma progression

More than 90% of hepatocellular carcinoma (HCC) cases develop in the presence of fibrosis or cirrhosis, making the tumor microenvironment (TME) of HCC distinctive due to the intricate interplay between cancer-associated fibroblasts (CAFs) and cancer stem cells (CSCs), which collectively regulate HCC progression. However, the mechanisms through which CSCs orchestrate the dynamics of the tumor stroma during HCC development remain elusive. Our study unveils a significant upregulation of Sema3C in fibrotic liver, HCC tissues, peripheral blood of HCC patients, as well as sorafenib-resistant tissues and cells, with its overexpression correlating with the acquisition of stemness properties in HCC. We further identify NRP1 and ITGB1 as pivotal functional receptors of Sema3C, activating downstream AKT/Gli1/c-Myc signaling pathways to bolster HCC self-renewal and tumor initiation. Additionally, HCC cells-derived Sema3C facilitated extracellular matrix (ECM) contraction and collagen deposition in vivo, while also promoting the proliferation and activation of hepatic stellate cells (HSCs). Mechanistically, Sema3C interacted with NRP1 and ITGB1 in HSCs, activating downstream NF-kB signaling, thereby stimulating the release of IL-6 and upregulating HMGCR expression, consequently enhancing cholesterol synthesis in HSCs. Furthermore, CAF-secreted TGF-β1 activates AP1 signaling to augment Sema3C expression in HCC cells, establishing a positive feedback loop that accelerates HCC progression. Notably, blockade of Sema3C effectively inhibits tumor growth and sensitizes HCC cells to sorafenib in vivo. In sum, our findings spotlight Sema3C as a novel biomarker facilitating the crosstalk between CSCs and stroma during hepatocarcinogenesis, thereby offering a promising avenue for enhancing treatment efficacy and overcoming drug resistance in HCC.

SND1 Regulates Organic Anion Transporter 2 Protein Expression and Sensitivity of Hepatocellular Carcinoma Cells to 5-Fluorouracil.

Hepatocellular carcinoma (HCC) is one of the most malignant tumors in the world. Inadequate efficacy of 5-fluorouracil (5-FU) on HCC could be related to low expression of human organic anion transporter 2 (OAT2). However, the knowledge of downregulation of OAT2 in HCC remains limited. We explored the underlying mechanism focusing on protein expression regulation and attempted to design a strategy to sensitize HCC cells to 5-FU. In this study, we revealed that the 1 bp to 300 bp region of OAT2 mRNA 3' untranslated region (UTR) reduced its protein expression and uptake activity in Li-7 and PLC/PRF/5 cells. Mechanistically, it was demonstrated that staphylococcal nuclease and Tudor domain containing 1 (SND1) bound at the 1 bp to 300 bp region of OAT2 mRNA 3' UTR, leading to a decrease in OAT2 protein expression. Enrichment analysis results indicated reduction of OAT2 might be mediated by translational inhibition. Furthermore, the knockdown of SND1 upregulated OAT2 protein expression and uptake activity. Based on this, decreasing SND1 expression enhanced 5-FU-caused G1/S phase arrest in Li-7 and PLC/PRF/5 cells, resulting in suppression of cell proliferation. Additionally, the knockdown of SND1 augmented the inhibitory effect of 5-FU on PLC/PRF/5 xenograft tumor growth in vivo by increasing OAT2 protein expression and accumulation of 5-FU in the tumor. Collectively, a combination of inhibition of SND1 with 5-FU might be a potential strategy to sensitize HCC cells to 5-FU from the perspective of restoring OAT2 protein level. SIGNIFICANCE STATEMENT: We investigated the regulatory mechanism of OAT2 protein expression in HCC cells and designed a strategy to sensitize them to 5-FU (OAT2 substrate) via restoring OAT2 protein level. It found that SND1, an RNA binding protein, regulated OAT2 protein expression by interacting with OAT2 mRNA 3' UTR 1-300 bp region. Through decreasing SND1, the antitumor effect of 5-FU on HCC was enhanced in vitro and in vivo, indicating that SND1 could be a potential target for sensitizing HCC cells to 5-FU.

Cyclin dependent kinase 9 inhibition reduced programmed death-ligand 1 expression and improved treatment efficacy in hepatocellular carcinoma

The anti-programmed death-ligand 1 (PD-L1) antibody is a standard therapy for advanced hepatocellular carcinoma (HCC). Tumor expression of PD-L1 can be induced upon stimulus. Because cyclin-dependent kinase 9 (CDK9) inhibition reduces the expression of inducible proteins, we explored the influence of CDK9 inhibition on PD-L1 expression in HCC cells. We found that PD-L1 expression was low in HCC cells; however, IFN-γ treatment increased this expression. CDK9 inhibitors AZD4573 and atuveciclib reduced the IFN-γ induced PD-L1 expression in a dose-dependent manner. CDK9 knockdown yielded similar results, but CDK9 overexpression reversed the influence of the CDK9 inhibitors. In the orthotopic mouse model, mice treated with a CDK9 inhibitor and an anti-PD-L1 antibody had significantly smaller tumors and exhibited longer survival than mice treated with either agent. In conclusion, CDK9 inhibition could reduce the expression of PD-L1 in HCC cells. Using both CDK9 inhibitors and anti-PD-L1 antibodies is more effective than using either agent alone.

Cannabidiol reverts the malignant phenotype of hepatocellular carcinoma cells via the GPR55/TP53/MAPK axis

Cannabidiol (CBD) has antioxidant and anti-inflammatory activities. However, the anti-tumor effect of CBD on hepatocellular carcinoma (HCC) remains unclear. Here, we investigated whether CBD displays anti-tumorigenic effects in HCC cells and whether it could reduce tumorigenesis and metastases in vivo. First, this study treated HCC cells with different concentrations of CBD, followed by analyzing the changes in the proliferative, apoptotic, migratory and invasive abilities. The effects of CBD on the growth and metastasis of HCC cells in vivo were verified by tumorigenesis and metastasis assays. Subsequently, the target genes of CBD were predicted through the SwissTarget website and the genes differentially expressed in cells after CBD treatment were analyzed by microarray for intersection. The enrichment of the pathways after CBD treatment was analyzed by KEGG enrichment analysis, followed by western blot validation. Finally, rescue assays were used to validate the functions of genes as well as pathways in the growth and metastasis of HCC cells. A significant weakening of the ability of HCC cells to grow and metastasize in vitro and in vivo was observed upon CBD treatment. Mechanistically, CBD reduced GRP55 expression in HCC cells, along with increased TP53 expression and blocked MAPK signaling activation. In CBD-treated cells, the anti-tumor of HCC cells was restored after overexpression of GRP55 or deletion of TP53. CBD inhibits the MAPK signaling activation and increases the TP53 expression by downregulating GRP55 in HCC cells, thereby suppressing the growth and metastasis of HCC cells.

Methylation-regulated tumor suppressor gene PDE7B promotes HCC invasion and metastasis through the PI3K/AKT signaling pathway.

Hepatocellular carcinoma (HCC) has a high mortality rate, and the mechanisms underlying tumor development and progression remain unclear. However, inactivated tumor suppressor genes might play key roles. DNA methylation is a critical regulatory mechanism for inactivating tumor suppressor genes in HCC. Therefore, this study investigated methylation-related tumor suppressors in HCC to identify potential biomarkers and therapeutic targets. We assessed genome-wide DNA methylation in HCC using whole genome bisulfite sequencing (WGBS) and RNA sequencing, respectively, and identified the differential expression of methylation-related genes, and finally screened phosphodiesterase 7B (PDE7B) for the study. The correlation between PDE7B expression and clinical features was then assessed. We then analyzed the changes of PDE7B expression in HCC cells before and after DNA methyltransferase inhibitor treatment by MassArray nucleic acid mass spectrometry. Furthermore, HCC cell lines overexpressing PDE7B were constructed to investigate its effect on HCC cell function. Finally, GO and KEGG were applied for the enrichment analysis of PDE7B-related pathways, and their effects on the expression of pathway proteins and EMT-related factors in HCC cells were preliminarily explored. HCC exhibited a genome-wide hypomethylation pattern. We screened 713 hypomethylated and 362 hypermethylated mCG regions in HCC and adjacent normal tissues. GO analysis showed that the main molecular functions of hypermethylation and hypomethylation were "DNA-binding transcriptional activator activity" and "structural component of ribosomes", respectively, whereas KEGG analysis showed that they were enriched in "bile secretion" and "Ras-associated protein-1 (Rap1) signaling pathway", respectively. PDE7B expression was significantly down-regulated in HCC tissues, and this low expression was negatively correlated with recurrence and prognosis of HCC. In addition, DNA methylation regulates PDE7B expression in HCC. On the contrary, overexpression of PDE7B inhibited tumor proliferation and metastasis in vitro. In addition, PDE7B-related genes were mainly enriched in the PI3K/ATK signaling pathway, and PDE7B overexpression inhibited the progression of PI3K/ATK signaling pathway-related proteins and EMT. PDE7B expression in HCC may be regulated by promoter methylation. PDE7B can regulate the EMT process in HCC cells through the PI3K/AKT pathway, which in turn affects HCC metastasis and invasion.

ARHGAP17 Inhibits Hepatocellular Carcinoma Progression by Inactivation of Wnt/β-Catenin Signaling Pathway

ARHGAP17 Inhibits Hepatocellular Carcinoma Progression by Inactivation of Wnt/β-Catenin Signaling Pathway

Unveiling the role of the KLF4/Lnc18q22.2/ULBP3 axis in the tumorigenesis and immune escape of hepatocellular carcinoma under hypoxic condition.

Hepatocellular carcinoma (HCC) represents a significant global health burden, necessitating an in-depth exploration of its molecular underpinnings to facilitate the development of effective therapeutic strategies. This investigation delves into the complex role of long non-coding RNAs (lncRNAs) in the modulation of hypoxia-induced HCC progression, with a specific emphasis on delineating and functionally characterizing the novel KLF4/Lnc18q22.2/ULBP3 axis. To elucidate the effects of hypoxic conditions on HCC cells, we established invitro models under both normoxic and hypoxic environments, followed by lncRNA microarray analyses. Among the lncRNAs identified, Lnc18q22.2 was found to be significantly upregulated in HCC cells subjected to hypoxia. Subsequent investigations affirmed the oncogenic role of Lnc18q22.2, highlighting its critical function in augmenting HCC cell proliferation and migration. Further examination disclosed that Kruppel-like factor 4 (KLF4) transcriptionally governs Lnc18q22.2 expression in HCC cells, particularly under hypoxic stress. KLF4 subsequently enhances the tumorigenic capabilities of HCC cells through the modulation of Lnc18q22.2 expression. Advancing downstream in the molecular cascade, our study elucidates a novel interaction between Lnc18q22.2 and UL16-binding protein 3 (ULBP3), culminating in the stabilization of ULBP3 protein expression. Notably, ULBP3 was identified as a pivotal element, exerting dual functions by facilitating HCC tumorigenesis and mitigating immune evasion in hypoxia-exposed HCC cells. The comprehensive insights gained from our research delineate a hitherto unidentified KLF4/Lnc18q22.2/ULBP3 axis integral to the understanding of HCC tumorigenesis and immune escape under hypoxic conditions. This newly unveiled molecular pathway not only enriches our understanding of hypoxia-induced HCC progression but also presents novel avenues for therapeutic intervention.

Antiproliferative Activity of N-Acylhydrazone Derivative on Hepatocellular Carcinoma Cells Involves Transcriptional Regulation of Genes Required for G2/M Transition.

Liver cancer is the second leading cause of cancer-related death in males. It is estimated that approximately one million deaths will occur by 2030 due to hepatic cancer. Hepatocellular carcinoma (HCC) is the most prevalent primary liver cancer subtype and is commonly diagnosed at an advanced stage. The drug arsenal used in systemic therapy for HCC is very limited. Multikinase inhibitors sorafenib (Nexavar®) and lenvatinib (Lenvima®) have been used as first-line drugs with modest therapeutic effects. In this scenario, it is imperative to search for new therapeutic strategies for HCC. Herein, the antiproliferative activity of N-acylhydrazone derivatives was evaluated on HCC cells (HepG2 and Hep3B), which were chemically planned on the ALL-993 scaffold, a potent inhibitor of vascular endothelial growth factor 2 (VEGFR2). The substances efficiently reduced the viability of HCC cells, and the LASSBio-2052 derivative was the most effective. Further, we demonstrated that LASSBio-2052 treatment induced FOXM1 downregulation, which compromises the transcriptional activation of genes required for G2/M transition, such as AURKA and AURKB, PLK1, and CDK1. In addition, LASSBio-2052 significantly reduced CCNB1 and CCND1 expression in HCC cells. Our findings indicate that LASSBio-2052 is a promising prototype for further in vivo studies.

Epigenetic Activation of Cytochrome P450 1A2 Sensitizes Hepatocellular Carcinoma Cells to Sorafenib.

Cytochrome P450 1A2 (CYP1A2) is a known tumor suppressor in hepatocellular carcinoma (HCC), but its expression is repressed in HCC and the underlying mechanism is unclear. In this study, we investigated the epigenetic mechanisms of CYP1A2 repression and potential therapeutic implications. In HCC tumor tissues, the methylation rates of CYP1A2 CpG island (CGI) and DNA methyltransferase (DNMT) 3A protein levels were significantly higher, and there was a clear negative correlation between DNMT3A and CYP1A2 protein expression. Knockdown of DNMT3A by siRNA significantly increased CYP1A2 expression in HCC cells. Additionally, treating HCC cells with decitabine (DAC) resulted in a dose-dependent upregulation of CYP1A2 expression by reducing the methylation level of CYP1A2 CGI. Furthermore, we observed a decreased enrichment of H3K27Ac in the promoter region of CYP1A2 in HCC tissues. Treatment with the trichostatin A (TSA) restored CYP1A2 expression in HCC cells by increasing H3K27Ac levels in the CYP1A2 promoter region. Importantly, combination treatment of sorafenib with DAC or TSA resulted in a leftward shift of the dose-response curve, lower IC50 values, and reduced colony numbers in HCC cells. Our findings suggest that hypermethylation of the CGI at the promoter, mediated by the high expression of DNMT3A, and hypoacetylation of H3K27 in the CYP1A2 promoter region, leads to CYP1A2 repression in HCC. Epigenetic drugs DAC and TSA increase HCC cell sensitivity to sorafenib by restoring CYP1A2 expression. Our study provides new insights into the epigenetic regulation of CYP1A2 in HCC and highlights the potential of epigenetic drugs as a therapeutic approach for HCC. SIGNIFICANCE STATEMENT: This study marks the first exploration of the epigenetic mechanisms underlying cytochrome P450 (CYP) 1A2 suppression in hepatocellular carcinoma (HCC). Our findings reveal that heightened DNA methyltransferase expression induces hypermethylation of the CpG island at the promoter, coupled with diminished H3K27Ac levels, resulting in the repression of CYP1A2 in HCC. The use of epigenetic drugs such as decitabine and trichostatin A emerges as a novel therapeutic avenue, demonstrating their potential to restore CYP1A2 expression and enhance sorafenib sensitivity in HCC cells.

USP40 promotes hepatocellular carcinoma progression through a YAP/USP40 positive feedback loop

Yes-associated protein (YAP) is an essential driver of hepatocellular carcinoma (HCC) progression and the ubiquitin-proteasome system controls its abundance. However, the role of ubiquitin-specific protease 40 (USP40) in YAP stability remains unclear. Here, USP40 was first identified as a novel regulator of YAP abundance and its target genes in HCC cells. USP40 interacted with YAP to remove the lysine 48 (K48)-linked polyubiquitination of YAP at K252 and K315 sites, thereby maintaining YAP stability. USP40 facilitated the proliferation, colony formation, migration and spheroid formation of HCC cells in vitro and promoted HCC growth in vivo in a YAP-dependent manner. In turn, YAP transcriptionally activated USP40 expression in HCC cells. RNA sequencing analysis showed that about 37% of USP40-regulated genes overlapped with YAP-regulated genes. Interestingly, stiffness-induced USP40 upregulation was abolished by YAP knockdown, and USP40 knockdown attenuated stiffness-induced YAP accumulation in HCC cells. Clinical data demonstrated that USP40 was positively associated with YAP expression in HCC tissues and its high expression indicated a poor prognosis. In conclusion, the USP40/YAP positive feedback loop contributes to HCC progression, suggesting that USP40 may be a promising drug target for anti-HCC.

Poorly Differentiated Hepatocellular Carcinoma Cells Avoid Apoptosis by Interacting with T Cells via CD40–CD40 Ligand Linkage

Hepatocellular carcinoma (HCC) is associated with elevated soluble CD40 levels in our previous study. Here we aimed to investigate CD40's role in liver tumor progression. We examined CD40 levels in HCC patient tissues and various HCC cell lines, studying their interaction with CD4+T cells. RNA sequencing analysis was performed to explore the mechanisms of CD40 induction. Poorly differentiated HCC tumour tissues exhibited high membrane-bound CD40 (mCD40) expression, in contrast to non-tumour areas. Poorly differentiated HCC cell lines showed high expression of mCD40 with low CD40 promoter methylation which were opposite of well-differentiated ones. Solely modulating CD40 expression in HCC cells exerted no direct consequences on cell growth or appearance. Interestingly, HLFs co-cultured with activated (CD40L+) CD4+ T cells elevated CD40 levels and showed a modest 3.2% of dead cells, then increased to 10.9% underwent pre-neutralizing CD40 condition, while pre-blocking both CD40 and Integrin α5β1 concomitantly caused only 1.9% of cell death. RNA sequencing of co-cultured HLFs with activated CD4+ T cells revealed the upregulation of interferon (IFN) and immune response pathways. Elevated IFN-γ levels in the activated T cell media stimulated the JAK1/STAT3 pathway, resulting in increased CD40 expression in HLF. Collectively, CD40 expression in poorly differentiated HCC cells prevents cell death by interacting with CD40L in activated T cells. Targeting CD40 may represent a promising anticancer therapy.