RESUMO
This study aims to explore the molecular regulation mechanism of ubiquitination-specific protease 7 (USP7) in facilitating the stemness properties of hepatocellular carcinoma (HCC). Gain-of-function and loss-of-function assays were conducted in SK-Hep1 and HepG2 cells transfected with USP7 overexpression/knockdown plasmids and USP7 inhibitor P22077. The proliferation, migration, invasion, and self-renewal capacity of hepatocellular carcinoma cells were detected by CCK-8, colony formation, Transwell, scratch, and tumor sphere formation, respectively. MS was performed to identify the potential substrate of USP7 following P22077 treatment. Co-IP assay was used to verify the interaction between USP7 and basic transcription factor 3 (BTF3) in HCC cells. The overexpression of USP7 could promote the proliferation, migration, invasion, and colony formation capacity of SK-Hep1 and HepG2 cells. Additionally, ectopic UPS7 enhanced the epithelial-mesenchymal transition (EMT) and stem-like characteristics of the HCC cells. In contrast, USP7 depletion by knockdown of USP7 or administrating inhibitor P22077 significantly inhibited these malignant phenotypes of SK-Hep1 and HepG2 cells. Following MS analysis, BTF3 was identified as a potential substrate for USP7. USP7 could interact with BTF3 and upregulate its protein level, while USP7 depletion significantly upregulated the ubiquitination levels. Overexpression of BTF3 partially rescue the inhibitory effects of USP7 depletion on the malignant phenotypes and stemness properties of SK-Hep1 and HepG2 cells. USP7 can promote the stemness and malignant phenotype of HCC by stabilizing BTF3.
Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Peptidase 7 Específica de Ubiquitina , Humanos , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Proliferação de Células/genética , Regulação Neoplásica da Expressão Gênica , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Tiofenos , Peptidase 7 Específica de Ubiquitina/genética , Peptidase 7 Específica de Ubiquitina/metabolismo , Ubiquitinação , Fatores de Transcrição/metabolismoRESUMO
PURPOSE: A variety of studies have connected circadian rhythm to the initiation and progression of hepatocellular carcinoma (HCC). The purpose of this study was to figure out about the circadian genes' profile characteristics, prognostic significance, and targeted values in HCC. METHODS: The expression profiles and prognostic significance of circadian genes in the cancer genome atlas liver hepatocellular carcinoma (TCGA-LIHC) database were investigated using bioinformatics analysis. The expression features of Casein Kinase 1 Delta (CSNK1D), a robust signature gene, was further detected by immunohistochemistry, western blotting and Real-time quantitative PCR (RT-qPCR) in a local HCC cohort. The effect of CSNK1D on corresponding phenotypes of HCC cells was evaluated using Cell Counting Kit-8 (CCK8), flowcytometry, clone assay, Transwell assay, and xenograft assay. In addition, the underlying mechanisms of CSNK1D in the Wnt/ß-catenin signaling were validated by multiple molecular experiments. RESULTS: Abnormal expression of the Circadian genome was associated with the malignant clinicopathological characteristics of HCC patients. A 10 circadian gene-based signature with substantial prognostic significance was developed using Cox regression and least absolute shrinkage and selection operator (LASSO) analysis. Of them, CSNK1D, significantly elevated in a local HCC cohort, was chosen for further investigation. Silencing or overexpression of CSNK1D significantly reduced or increased proliferation, invasion, sorafenib resistance, xenograft development, and epithelial-mesenchymal transformation (EMT) of HCC cells, respectively. Mechanically, CSNK1D exacerbated the aggressiveness of HCC cells by activating Wnt/ß-catenin signaling through interacting with Dishevelled Segment Polarity Protein 3 (DVL3). CONCLUSIONS: The Circadian gene CSNK1D was found to contribute to HCC progression by boosting the Wnt/ß-catenin pathway, hinting that it could be a prospective therapeutic target for HCC.
RESUMO
BACKGROUND: Ubiquitin-specific protease 7 (USP7) is a de-ubiquitin enzyme that plays an essential role in multiple cancers and becomes a target for treatment. However, the role of USP7 and its therapeutic value for HCC remains unclear. METHODS: USP7 expression was examined in HCC tissues by western blot and immunohistochemistry. The correlation of USP7 and HCC prognosis was analyzed by Kaplan-Meier survival method. Mass spectrometry was determined and cell proliferation and tumorigenicity assays were conducted in vitro and in vivo treated by P22077 and sgRNA-USP7. RESULTS: USP7 expression was significantly increased in HCC and associated with its progression. Interestingly, many HCC cells are sensitive to USP7 inhibition by using P22077. P22077 treatment not only induced cell death but also inhibited cell proliferation and migration in Huh7 and SK-Hep1 cells. In a xenograft model, P22077 efficiently inhibited tumor growth. In chemo-resistant HCC cells, P22077 decreased cell sensitivity to chemotherapy. In addition, mass spectrometry reveals 224 of significantly changed proteins upon P22077 treatment. CONCLUSIONS: We demonstrate a critical role of USP7 in HCC devolvement and chemoresistance. Disruption of USP7 function results in dis-regulated several key biological processes and subsequently activates BAX. USP7 might be a novel and drug-able target in HCC.
RESUMO
Although deubiquitinases (DUBs) have been well described in liver tumorigenesis, their potential roles and mechanisms have not been fully understood. In this study, we identified ubiquitin-specific protease 1 (USP1) as an oncogene with essential roles during hepatocellular carcinoma (HCC) progression. USP1, with elevated expression levels and clinical significance, was identified as a hub DUB for HCC in multiple bioinformatics datasets. Functionally, USP1 overexpression significantly enhanced the malignant behaviors in HCC cell lines and spheroids in vitro, as well as the zebrafish model and the xenograft model in vivo. In contrast, genetic ablation or pharmacological inhibition of USP1 dramatically impaired the phenotypes of HCC cells. Specifically, ectopic USP1 enhanced aggressive properties and metabolic reprogramming of HCC cells by modulating mitochondrial dynamics. Mechanistically, USP1 induced mitochondrial fission by enhancing phosphorylation of Drp1 at Ser616 via deubiquitination and stabilization of cyclin-dependent kinase 5 (CDK5), which could be degraded by the E3 ligase NEDD4L. The USP1/CDK5 modulatory axis was activated in HCC tissues, which was correlated with poor prognosis of HCC patients. Furthermore, Prasugrel was identified as a candidate USP1 inhibitor for targeting the phenotypes of HCC by an extensive computational study combined with experimental validations. Taken together, USP1 induced malignant phenotypes and metabolic reprogramming by modulating mitochondrial dynamics in a CDK5-mediated Drp1 phosphorylation manner, thereby deteriorating HCC progression.
RESUMO
Mesenchymal stem cells (MSCs) have been identified as potential therapeutics for various diseases. In contrast to other sources of MSCs, dental stem cells (DSCs) have received increased attention due to their high activity and easy accessibility. Among them, dental pulp stem cells (DPSCs) exhibit superior self-renewal, multipotency, immunomodulatory, and regenerative capacities. Following their inspiring performance in animal models and clinical trials, DPSCs show pharmacological potential in regenerative medicine. In this review, we have generalized the sources, heterogeneity, and biological characteristics of DPSCs, as well as compared them with other types of dental stem cells. In addition, we summarized the application of DPSCs in digestive diseases (such as liver, esophageal, and intestinal diseases), highlighting their regenerative and pharmacological potential based on the existing preclinical and clinical evidence. Specifically, DPSCs can be> home to injured or inflamed tissues and exert repair and regeneration functions by> facilitating immune regulation, anti-inflammation, and directional differentiation. Although DPSCs have a rosy prospect, future studies should handle the underlying drawbacks and pave the way for the identification of DPSCs as novel regenerative medicine.
RESUMO
With limited therapeutic options for hepatocellular carcinoma (HCC), it is of great significance to investigate the underlying mechanisms and identifying tumor drivers. MCM6, a member of minichromosome maintenance proteins (MCMs), was significantly elevated in HCC progression and associated with poor prognosis. Knockdown of MCM6 significantly inhibited the proliferation and migration of HCC cells with the increased apoptosis ratio and cell cycle arrest, whereas overexpression of MCM6 induced adverse effects. Mechanistically, MCM6 could decrease the P53 activity by inducing the degradation of P53 protein. In addition, MCM6 enhanced the ubiquitination of P53 by recruiting UBE3A to form a triple complex. Furthermore, overexpression of UBE3A significantly rescued the P53 activation and suppression of malignant behaviors mediated by MCM6 inhibition. In conclusion, MCM6 facilitated aggressive phenotypes of HCC cells by UBE3A/P53 signaling, providing potential biomarkers and targets for HCC.
Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Humanos , Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/patologia , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Proteínas de Manutenção de Minicromossomo/genética , Proteínas de Manutenção de Minicromossomo/metabolismo , Ubiquitinação , Família , Proliferação de Células , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismoRESUMO
BACKGROUND: Extracellular vesicles derived from mesenchymal stem/stromal cells (MSCs) have shown therapeutic effects on liver fibrosis. This study aimed to evaluate the effects of extracellular vesicles from placenta-derived MSCs (Pd-MSCs-EVs) on liver fibrosis at 3D/2D levels and explore the potential mechanisms. METHODS: The multicellular liver organoids, consisting of hepatocytes, hepatic stellate cells (HSCs), Kupffer cells, and liver sinusoidal endothelial cells, were observed for growth status, morphological changes, and metabolism. Human transformation growth factor- beta 1 (TGF-ß1) was used to induce fibrosis at optimal concentration. The anti-fibrosis effects of Pd-MSCs-EVs were evaluated in liver organoids and HSCs models. Anti-fibrotic content of Pd-MSCs-EVs was identified by multiple experimental validations. RESULTS: TGF-ß1 induced fibrosis in liver organoids, while Pd-MSCs-EVs significantly alleviated fibrotic phenotypes. Following serial verifications, miR-378c was identified as a potential key anti-fibrosis content. In contrast, miR-378c depletion decreased the anti-fibrotic effects of Pd-MSCs-EVs. Additionally, Pd-MSCs-EVs administration repressed TGF-ß1-mediated HSCs activation at 2D or 3D levels. Mechanistically, exosomal miR-378c inactivated HSCs by inhibiting epithelial-mesenchymal transition (EMT) through stabilizing E-cadherin via targeting its E3 ubiquitin ligase S-Phase Kinase Associated Protein 2 (SKP2). CONCLUSION: Pd-MSCs-EVs ameliorated TGF-ß1-induced fibrosis by deactivating HSCs in a miR-378c/SKP2-dependent manner, which may be an efficient therapeutic candidate for liver fibrosis.
RESUMO
As the predominant stroma cells of tumor microenvironment (TME), cancer associated fibroblasts (CAFs) are robust tumor player of different malignancies. However, less is known about the regulatory mechanism of CAFs on promoting progression of ovarian cancer (OvCA). In the present study, the conditioned medium of primary CAFs (CAF-CM) from OvCA was used to culture cell lines of epithelial ovarian cancer (EOC), and showed a potent role in promoting proliferation, migration and invasion of cancer cells. Mass spectrum (MS) analysis identified that Collapsin response mediator protein-2 (CRMP2), a microtubule-associated protein involved in diverse malignancies, derived from CAFs was a key regulator responsible for mediating these cell events of OvCA. In vitro study using recombinant CRMP2 (r-CRMP2) revealed that the protein promoted proliferation, invasion, and migration of OvCA cells through activation of hypoxia-inducible factor (HIF)-1α-glycolysis signaling pathway. The CRMP2 was abundantly expressed in OvCA, with a well correlation with metastasis and poor prognosis, as analyzed from 118 patients' samples. Inhibition of the CRMP2 derived from CAFs by neutralizing antibodies significantly attenuated the tumor size, weights, and metastatic foci numbers of mice in vivo. Our finding has provided a novel therapeutic clue for OvCA based on TME.
Assuntos
Fibroblastos Associados a Câncer , Neoplasias Ovarianas , Animais , Fibroblastos Associados a Câncer/metabolismo , Carcinoma Epitelial do Ovário/metabolismo , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Feminino , Fibroblastos/metabolismo , Glicólise , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia , Peptídeos e Proteínas de Sinalização Intercelular , Camundongos , Proteínas do Tecido Nervoso , Neoplasias Ovarianas/patologia , Transdução de Sinais , Microambiente TumoralRESUMO
Overexpression of Flap endonuclease 1 (FEN1) has been previously implicated in hepatocellular carcinoma (HCC), while its expression features and mechanisms remain unclear. In the current study, differential expression genes (DEGs) were screened in HCC tissues and normal liver tissues in 4 Gene Expression Omnibus (GEO) datasets. FEN1, one of the hub co-overexpressed genes, was further determined overexpressed in HCC tissues in TCGA, local HCC cohorts, and hepatocarcinogenesis model. In addition, high expression of FEN1 indicated poor prognosis of HCC patients. Loss-of-function and gain-of-function assays demonstrated that FEN1 enhanced the proliferation, cell cycle phage transition, migration/ invasion, therapy resistance, xenograft growth, and epithelial-mesenchymal transition (EMT) process of HCC cells. Mechanically, FEN1 could inactivate P53 signaling by preventing the ubiquitination and degradation of mouse double minute 2 (MDM2) via recruiting ubiquitin-specific protease 7 (USP7). Interfering USP7 with P22077 significantly reversed the malignant phenotypes activated by FEN1. In conclusion, this study suggests FEN1 as a robust prognostic biomarker and potential target for HCC.
Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Animais , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Proliferação de Células/genética , Transição Epitelial-Mesenquimal/genética , Endonucleases Flap/genética , Endonucleases Flap/metabolismo , Regulação Neoplásica da Expressão Gênica/genética , Humanos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Camundongos , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Peptidase 7 Específica de Ubiquitina/genética , Peptidase 7 Específica de Ubiquitina/metabolismoRESUMO
Accumulating evidence has demonstrated that long noncoding RNA (lncRNA) is importantly related to the occurrence and development of cancer. According to reports, the expression of B3GALT5-AS1 in hepatocellular carcinoma (HCC) is downregulated; however, the role of B3GALT5-AS1 in HCC is not yet clear. In this study, our purpose is to explore the biological function of B3GALT5-AS1 in HCC and its coupling mechanism with miR-934 and ubiquitin-fold modifier 1 (UFM1). We found that the B3GALT5-AS1 expression level was of significant reduction in both HCC tissues and cell lines; B3GALT5-AS1 overexpression (ov) may inhibit the malignant features of HCC. In addition, we demonstrated that miR-934 mimics could reverse the effect of B3GALT5-AS1 ov, which proved miR-934 was the downstream regulator of B3GALT5-AS1. Furthermore, si-UFM1 could reverse the effect of miR-934 inhibitor, which revealed the connection between them. Moreover, we found that B3GALT5-AS1 could keep down the PI3K/AKT pathway through UFM1. Our results demonstrated that B3GALT5-AS1 was an excellent HCC suppressant by regulating miR-934 and UFM1 to achieve negative regulation of HCC cell proliferation, invasion, and metastasis, indicating that B3GALT5-AS1 is a promising potential therapeutic target for HCC treatment.
RESUMO
PURPOSE: Ubiquitin-specific proteases (USPs), as a sub-family of deubiquitinating enzymes (DUBs), are responsible for the elimination of ubiquitin-triggered modification. USPs are recently correlated with various malignancies. However, the expression features and clinical significance of USPs have not been systematically investigated in hepatocellular carcinoma (HCC). METHODS: Genomic alterations and expression profiles of USPs were investigated in CbioPortal and The Cancer Genome Atlas (TCGA) Liver hepatocellular carcinoma (LIHC) dataset. Cox regression and least absolute shrinkage and selection operator (LASSO) analyses were conducted to establish a risk signature for HCC prognosis in TCGA LIHC cohort. Subsequently, Kaplan-Meier analysis, receiver operating characteristic (ROC) curves and univariate/multivariate analyses were performed to evaluate the prognostic significance of the risk signature in TCGA LIHC and international cancer genome consortium (ICGC) cohorts. Furthermore, we explored the alterations of the signature genes during hepatocarcinogenesis and HCC progression in GSE89377. In addition, the expression feature of USP39 was further explored in HCC tissues by performing western blotting and immunohistochemistry. RESULTS: Genomic alterations and overexpression of USPs were observed in HCC tissues. The consensus analysis indicated that the USPs-overexpressed sub-Cluster was correlated with aggressive characteristics and poor prognosis. Cox regression with LASSO algorithm identified a risk signature formed by eight USPs for HCC prognosis. High-risk group stratified by the signature score was correlated with advanced tumor stage and poor survival HCC patients in TCGA LIHC cohort. In addition, the 8-USPs based signature could also robustly predict overall survival of HCC patients in ICGC(LIRI-JP) cohort. Furthermore, gene sets enrichment analysis (GSEA) showed that the high-risk score was associated with tumor-related pathways. According to the observation in GSE89377, USP39 expression was dynamically increased with hepatocarcinogenesis and HCC progression. The overexpression of USP39 was further determined in a local HCC cohort and correlated with poor prognosis. The co-concurrence analysis suggested that USP39 might promote HCC by regulating cell-cycle- and proliferation- related genes. CONCLUSION: The current study provided a USPs-based signature, highlighting its robust prognostic significance and targeted value for HCC treatment.
RESUMO
Understanding organogenesis, disorders, and repairing processes is particularly important for understanding the disease occurrence and developing treatment approaches. At present, liver- related studies are mainly conducted using in vivo models and cell lines, making it difficult to generalize the full picture of the structural characteristics and functions of human organs. Organoid is a three-dimensional (3D) culture system in vitro, which holds the promise to establish various disease models and conduct in-depth research by generating organ-like tissues in a dish. Recent advances in human liver organoids have provided a deeper understanding of this complex organ. In this review, we provide a systematic overview of the construction methods of organoids, focusing on their applications in the hepatic organogenesis and various liver disease models, as well as the limitations of current models. The development of organoid models is proving to be crucial in future liver research.
Assuntos
Hepatopatias , Organoides , Linhagem Celular , Humanos , Hepatopatias/tratamento farmacológico , Preparações FarmacêuticasRESUMO
OBJECTIVES: Endoscopic submucosal dissection (ESD), a preferential approach for early oesophageal neoplasms, inevitably results in oesophageal strictures in patients. Clinical use of glucocorticoids through submucosal injection is beneficial for inhibiting oesophageal stricture following injury; however, it also has limitations, such as dose loss and perforation. Hence, alternatives to glucocorticoid therapy should be developed. METHODS: A novel porous composite scaffold, ChCo-TAMS, composed of chitosan, collagen-I and triamcinolone acetonide (TA) loaded into poly (lactic-co-glycolic) acid (PLGA) microspheres (TAMS), was successfully constructed and subjected to biological testing to ameliorate oesophageal ESD-related stenosis. RESULTS: The synthesized biomaterials displayed unique properties in inhibiting the activation of macrophages, chemokine-mediated cell recruitment and fibrogenesis of fibroblasts. Further application of the scaffolds in the rat dermal defect and porcine oesophageal ESD model showed that these novel scaffolds played a robust role in inhibiting wound contracture and oesophageal ESD strictures. CONCLUSIONS: The developed composite scaffolds provide a promising clinical medical device for the prevention of post-operative oesophageal stricture.
Assuntos
Quitosana/farmacologia , Colágeno/efeitos dos fármacos , Constrição Patológica/patologia , Neoplasias Esofágicas/tratamento farmacológico , Estenose Esofágica/tratamento farmacológico , Animais , Materiais Biocompatíveis/metabolismo , Quitosana/metabolismo , Colágeno/metabolismo , Constrição Patológica/etiologia , Neoplasias Esofágicas/patologia , Estenose Esofágica/prevenção & controle , Camundongos , Microesferas , Triancinolona/metabolismo , Triancinolona Acetonida/administração & dosagem , Triancinolona Acetonida/farmacologiaRESUMO
BACKGROUND: DNA primase subunit 1 (PRIM1) has been reported as a novel oncogene in several cancer types. However, its roles in hepatocellular carcinoma (HCC) remain unclear. This study aimed to investigate underlying mechanisms of PRIM1 and identify it as a potential molecular target for HCC. METHODS: Hub genes were screened between HCC tissues and normal liver tissues in 3 gene expression omnibus (GEO) datasets and the cancer genome atlas (TCGA). The expression features and prognostic value of one of the hub genes PRIM1 were analyzed by bioinformatic analyses and immunohistochemistry. Loss-of-function and gain-of-function studies were used to investigate the regulatory role of PRIM1 in HCC cells. Real-time (RT)-qPCR, western blotting, and ubiquitin immunoprecipitation assays were performed to explore the underlying mechanisms. The xenograft model was employed to detect the roles of PRIM1 in tumor growth in vivo. Finally, the 3D spheroid model was conducted to validate the role of PRIM1 in tumor growth and sorafenib resistance. RESULTS: The hub genes of HCC were screened in multiple bioinformatic datasets. PRIM1, as one of the hub genes, was significantly overexpressed in HCC tissues in mRNA and protein levels. In addition, high expression of PRIM1 indicated poor prognosis of HCC patients in TCGA, ICGC, and Nantong cohorts. Overexpression of PRIM1 promoted the proliferation, migration/invasion, and sorafenib resistance of HCC cells, with the decrease in apoptosis and cell cycle arrest. Mechanically, PRIM1 facilitated epithelial-mesenchymal transition (EMT) process and the activity of PI3K/AKT/mTOR signaling of HCC cells. Additionally, PRIM1 could cause the ubiquitination and degradation of P53 by upregulating Ubiquitin Conjugating Enzyme E2 C (UBE2C). Furthermore, knockdown of PRIM1 significantly inhibited the growth of xenograft tumors and HCC cells-derived spheroids with enhanced sorafenib resistance. CONCLUSION: This study implies that PRIM1 may play a key role in the progression of HCC and may serve as a potential target for HCC treatment.
RESUMO
Purpose: N6-methyladenosine (m6A) RNA methylation has been implicated in various malignancies. This study aimed to identify the m6A methylation regulator-based prognostic signature for hepatocellular carcinoma (HCC) as well as provide candidate targets for HCC treatment. Methods: The least absolute shrinkage and selection operator (LASSO) analyses were performed to identify a risk signature in The Cancer Genome Atlas (TCGA) datasets. The risk signature was further validated in International Cancer Genome Consortium (ICGC) and Pan-Cancer Analysis of Whole Genomes (PCAWG) datasets. Following transfection of short hairpin RNA (shRNA) targeting YTHDF1, the biological activities of HCC cells were evaluated by Cell Counting Kit-8 (CCK-8), wound-healing, Transwell, flow cytometry, and xenograft tumor assays, respectively. The potential mechanisms mediated by YTHDF1 were predicted by overrepresentation enrichment analysis (ORA)/gene set enrichment analysis (GSEA) and validated by Western blotting. Results: Overexpression of m6A RNA methylation regulators was correlated with malignant clinicopathological characteristics of HCC patients. The Cox regression and LASSO analyses identified a risk signature with five m6A methylation regulators (KIAA1429, ZC3H13, YTHDF1, YTHDF2, and METTL3). In accordance with HCC cases in TCGA, the prognostic value of risk signature was also determined in ICGC and PCAWG datasets. Following analyzing the expression and clinical implications in TCGA and Gene Expression Omnibus (GEO), YTHDF1 was chosen for further experimental validation. Knockdown of YTHDF1 significantly inhibited the proliferation, migration, and invasion of HCC cells, as well as enhanced the apoptosis in vitro. Moreover, silencing YTHDF1 repressed the growth of xenograft tumors in vivo. Mechanism investigation indicated that YTHDF1 might promote the aggressive phenotypes by facilitating epithelial-mesenchymal transition (EMT) and activating AKT/glycogen synthase kinase (GSK)-3ß/ß-catenin signaling. Conclusion: The current study identified a robust risk signature consisting of m6A RNA methylation regulators for HCC prognosis. In addition, YTHDF1 was a potential molecular target for HCC treatment.
RESUMO
Aberrant de novo lipogenesis (DNL) results in excessive hepatic lipid accumulation and liver steatosis, the causative factors of many liver diseases, such as non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), and hepatocellular carcinoma (HCC). However, the underlying mechanism of DNL dysregulation remains largely unknown. Ubiquitination of proteins in hepatocytes has been shown to be widely involved in lipid metabolism of liver. Here, we revealed that Ubiquitin-specific peptidase 7 (USP7), a deubiquitinase (DUB), played key roles in DNL through regulation of zinc finger protein 638 (ZNF638) in hepatocytes. USP7 has been shown not only to interact with and deubiquitylate ZNF638, but also to facilitate the transcription of ZNF638 via the stabilization of cAMP responsive element binding protein (CREB). USP7/ZNF638 axis selectively increased the cleavage of sterol regulatory element binding protein (SREBP1C) through AKT/mTORC1/S6K signaling, and formed USP7/ZNF638/SREBP1C nuclear complex to regulate lipogenesis-associated enzymes, including acetyl-CoA carboxylase (ACACA), fatty acid synthase (FASN), and Stearoyl-CoA desaturase (SCD). In the mice liver steatosis model induced by fructose, USP7 or ZNF638 abrogation significantly ameliorated disease progression. Furthermore, USP7/ZNF638 axis participated in the progression of lipogenesis-associated HCC. Our results have uncovered a novel mechanism of hepatic DNL, which might be beneficial to the development of new therapeutic targets for hepatic lipogenesis-associated diseases.