Deficiency in SLC25A15, a hypoxia-responsive gene, promotes hepatocellular carcinoma by reprogramming glutamine metabolism.

BACKGROUND & AIMS: The role of solute carrier family 25 member 15 (SLC25A15), a critical component of the urea cycle, in hepatocellular carcinoma (HCC) progression remains poorly understood. This study investigated the impact of SLC25A15 on HCC progression and its mechanisms. METHODS: We systematically investigated the function of SLC25A15 in HCC progression using large-scale data mining and cell, animal, and organoid models. Furthermore, we analyzed its involvement in reprogramming glutamine metabolism. RESULTS: SLC25A15 expression was significantly decreased in HCC tissues, and patients with low SLC25A15 levels had a poorer prognosis. Hypoxia-exposed HCC cells or tissues had lower SLC25A15 expression. A positive correlation between HNF4A, a transcription factor suppressed by hypoxia, and SLC25A15 was observed in both HCC tissues and cells. Modulating HNF4A levels altered SLC25A15 mRNA levels. SLC25A15 upregulated SLC1A5, increasing glutamine uptake. The reactive metabolic pathway of glutamine was increased in SLC25A15-deficient HCC cells, providing energy for HCC progression through additional lipid synthesis. Ammonia accumulation due to low SLC25A15 levels suppressed the expression of OGDHL (oxoglutarate dehydrogenase L), a switch gene that mediates SLC25A15 deficiency-induced reprogramming of glutamine metabolism. SLC25A15-deficient HCC cells were more susceptible to glutamine deprivation and glutaminase inhibitors. Intervening in glutamine metabolism increased SLC25A15-deficient HCC cells' response to anti-PD-L1 treatment. CONCLUSION: SLC25A15 is hypoxia-responsive in HCC, and low SLC25A15 levels result in glutamine reprogramming through SLC1A5 and OGDHL regulation, promoting HCC progression and regulating cell sensitivity to anti-PD-L1. Interrupting the glutamine-derived energy supply is a potential therapeutic strategy for treating SLC25A15-deficient HCC. IMPACT AND IMPLICATIONS: We first demonstrated the tumor suppressor role of solute carrier family 25 member 15 (SLC25A15) in hepatocellular carcinoma (HCC) and showed that its deficiency leads to reprogramming of glutamine metabolism to promote HCC development. SLC25A15 can serve as a potential biomarker to guide the development of precision therapeutic strategies aimed at targeting glutamine deprivation. Furthermore, we highlight that the use of an inhibitor of glutamine utilization can enhance the sensitivity of low SLC25A15 HCC to anti-PD-L1 therapy.

Risk Models for Predicting the Recurrence and Survival in Patients With Hepatocellular Carcinoma Undergoing Radio-Frequency Ablation.

Background: Hepatocellular carcinoma (HCC) patients have a poor prognosis after radio-frequency ablation (RFA), and investigating the risk factors affecting RFA and establishing predictive models are important for improving the prognosis of HCC patients. Methods: Patients with HCC undergoing RFA in Shenzhen People's Hospital between January 2011 and December 2021 were included in this study. Using the screened independent influences on recurrence and survival, predictive models were constructed and validated, and the predictive models were then used to classify patients into different risk categories and assess the prognosis of different categories. Results: Cox regression model indicated that cirrhosis (hazard ratio [HR] = 1.65), alpha-fetoprotein (AFP) ⩾400 ng/mL (HR = 2.03), tumor number (multiple) (HR = 2.11), tumor diameter ⩾20 mm (HR = 2.30), and platelets (PLT) ⩾ 244 (109/L) (HR = 2.37) were independent influences for recurrence of patients after RFA. On the contrary, AFP ⩾400 ng/mL (HR = 2.48), tumor number (multiple) (HR = 2.52), tumor diameter ⩾20 mm (HR = 2.25), PLT ⩾244 (109/L) (HR = 2.36), and hemoglobin (HGB) ⩾120 (g/L) (HR = 0.34) were regarded as independent influences for survival. The concordance index (C-index) of the nomograms for predicting disease-free survival (DFS) and overall survival (OS) was 0.727 (95% confidence interval [CI] = 0.770-0.684) and 0.770 (95% CI = 0.821-7.190), respectively. The prognostic performance of the nomograms was significantly better than other staging systems by analysis of the time-dependent C-index and decision curves. Each patient was scored using nomograms and influencing factors, and patients were categorized into low-, intermediate-, and high-risk groups based on their scores. In the Kaplan-Meier survival curve, DFS and OS were significantly better in the low-risk group than in the intermediate- and high-risk groups. Conclusions: The 2 prediction models created in this work can effectively predict the recurrence and survival rates of HCC patients following RFA.

Exploring the factors affecting the occurrence of postoperative MVI and the prognosis of hepatocellular carcinoma patients treated with hepatectomy: A multicenter retrospective study.

OBJECTIVE: To investigate the influencing factors affecting the occurrence of microvascular invasion (MVI) and the prognosis of hepatocellular carcinoma (HCC) patients treated with hepatectomy, and to explore how MVI affects prognosis in subgroups with different prognostic factors. METHODS: Clinical data of a total of 1633 patients treated surgically for HCC in four treatment centers were included, including 754 patients with MVI. By using the Cox risk regression model and the Mann-Whitney U-test, the common independent influences on prognosis and MVI were made clear. The incidence of MVI in various subgroups was then examined, as well as the relationship between MVI in various subgroups and prognosis. RESULTS: The Cox risk regression model showed that MVI, Child-Pugh classification, alpha-fetoprotein (AFP), hepatocirrhosis, tumor diameter, lymphocyte-to-monocyte ratio (LMR), and, Barcelona clinic liver cancer (BCLC) grade were independent determinants of overall survival (OS), and MVI, AFP, hepatocirrhosis, tumor diameter, and LMR were influencing determinants for disease-free survival (DFS). The receiver operating characteristic (ROC) curve showed that MVI was most closely associated with patient prognosis compared to other prognostic factors. AFP, hepatocirrhosis, tumor diameter, and LMR were discovered to be common influences on the prognosis of patients with HCC and MVI when combined with the results of the intergroup comparison of MVI. After grouping, it was showed that patients with hepatocirrhosis, positive AFP (AFP ≥ 20 ng/mL), tumor diameter >50 mm, and LMR ≤3.4 had a significantly higher incidence of MVI than patients in other subgroups, and all four subgroups of MVI-positive patients had higher rates of early recurrence and mortality (p < 0.05). CONCLUSIONS: MVI was found to be substantially linked with four subgroups of HCC patients with hepatocirrhosis, positive AFP, tumor diameter >50 mm, and LMR ≤3.4, and the prognosis of MVI-positive patients in all four subgroups tended to be worse.

IHGA: An interactive web server for large-scale and comprehensive discovery of genes of interest in hepatocellular carcinoma.

Mining gene expression data is valuable for discovering novel biomarkers and therapeutic targets in hepatocellular carcinoma (HCC). Although emerging data mining tools are available for pan-cancer-related gene data analysis, few tools are dedicated to HCC. Moreover, tools specifically designed for HCC have restrictions such as small data scale and limited functionality. Therefore, we developed IHGA, a new interactive web server for discovering genes of interest in HCC on a large-scale and comprehensive basis. Integrative HCC Gene Analysis (IHGA) contains over 100 independent HCC patient-derived datasets (with over 10,000 tissue samples) and more than 90 cell models. IHGA allows users to conduct a series of large-scale and comprehensive analyses and data visualizations based on gene mRNA levels, including expression comparison, correlation analysis, clinical characteristics analysis, survival analysis, immune system interaction analysis, and drug sensitivity analysis. This method notably enhanced the richness of clinical data in IHGA. Additionally, IHGA integrates artificial intelligence (AI)-assisted gene screening based on natural language models. IHGA is free, user-friendly, and can effectively reduce time spent during data collection, organization, and analysis. In conclusion, IHGA is competitive in terms of data scale, data diversity, and functionality. It effectively alleviates the obstacles caused by HCC heterogeneity to data mining work and helps advance research on the molecular mechanisms of HCC.

Hypoxia-Responsive lncRNA AC115619 Encodes a Micropeptide That Suppresses m6A Modifications and Hepatocellular Carcinoma Progression.

Long noncoding RNAs (lncRNA) regulate a number of aspects of cancer biology. Recent research has shown that lncRNAs can encode micropeptides that mediate their functions in tumors. Here, we revealed that the liver-specific putative lncRNA, AC115619, is expressed at low levels in hepatocellular carcinoma (HCC) and encodes a micropeptide, designated as AC115619-22aa. AC115619 played a crucial role in the regulation of tumor progression and was a prognostic indicator in HCC. The encoded micropeptide AC115619-22aa inhibited the progression of HCC by binding to WTAP and impeding the assembly of the N6-methyladenosine (m6A) methyltransferase complex, which regulates the expression of tumor-associated genes, such as SOCS2 and ATG14. AC115619 was cotranscribed with the adjacent upstream coding gene APOB, and hypoxia induced transcriptional repression of both APOB and AC115619 by controlling HIF1A/HDAC3 and HNF4A signaling. In animal and patient-derived models, AC115619-22aa reduced global m6A levels and suppressed tumor growth. In conclusion, this study establishes AC115619 and its encoded micropeptide as potential prognostic markers and therapeutic targets for patients with HCC. SIGNIFICANCE: A micropeptide encoded by lncRNA AC115619 impedes formation of the m6A methylation complex to lower m6A levels and reduce the growth of hepatocellular carcinoma.

Hypoxia-responsive PPARGC1A/BAMBI/ACSL5 axis promotes progression and resistance to lenvatinib in hepatocellular carcinoma.

Emerging evidence has indicated that peroxisome proliferator-activated receptor-gamma coactivator-1α (PPARGC1A) is involved in hepatocellular carcinoma (HCC). However, its detailed function and up- and downstream mechanisms are incompletely understood. In this study, we confirmed that PPAGC1A is lowly expressed in HCC and is associated with poor prognosis using large-scale public datasets and in-house cohorts. PPAGC1A was found to impair the progression and sensitivity of HCC to lenvatinib. Mechanistically, PPAGC1A repressed bone morphogenetic protein and activin membrane-bound inhibitor (BAMBI) by inhibiting WNT/ß-catenin signaling. BAMBI mediated the function of PPARGC1A and regulated ACSL5 through TGF-ß/SMAD signaling. PPARGC1A/BAMBI regulated ROS production and ferroptosis-related cell death by controlling ACSL5. PPARGC1A/BAMBI/ACSL5 axis was hypoxia-responsive. METTL3 and WTAP silenced PPARGC1A in an m6A-YTHDF2-dependent way under normoxia and hypoxia, respectively. Metformin restored PPARGC1A expression by reducing its m6A modification via inhibiting METTL3. In animal models and patient-derived organoids, consistent functional data of PPARGC1A/BAMBI/ACSL5 were observed. Conclusions: These findings provide new insights into the role of the aberrant PPARGC1A/BAMBI/ACSL5 axis in HCC. And the mechanism of PPARGC1A dysregulation was explained by m6A modification. Metformin may benefit HCC patients with PPARGC1A dysregulation.

Automatic Segmentation of Magnetic Resonance Images of Severe Patients with Advanced Liver Cancer and the Molecular Mechanism of Emodin-Induced Apoptosis of HepG2 Cells under the Deep Learning.

To improve the accuracy of clinical diagnosis of severe patients with advanced liver cancer and enhance the effect of chemotherapy treatment, the U-Net model was optimized by introducing the batch normalization (BN) layer and the dropout layer, and the segmentation training and verification of the optimized model were realized by the magnetic resonance (MR) image data. Subsequently, HepG2 cells were taken as the research objects and treated with 0, 10, 20, 40, 60, 80, and 100 µmol/L emodin (EMO), respectively. The methyl thiazolyl tetrazolium (MTT) method was used to explore the changes in cell viability, the acridine orange (AO)/ethidium bromide (EB) and 4',6-diamidino-2-phenylindole (DAPI) were used for staining, the Annexin V fluorescein isothiocyanate (FITC)/propidium iodide (PI) (Annexin V-FITC/PI) was adopted to detect the apoptosis after EMO treatment, and the Western blot (WB) method was used with the purpose of exploring the changes in protein expression levels of PARP, Bcl-2, and p53 in the cells after treatment. It was found that compared with the original U-Net model, the introduction of the BN layer and the dropout layer can improve the robustness of the U-Net model, and the optimized U-Net model had the highest dice similarity coefficient (DSC) (98.45%) and mean average precision (MAP) (0.88) for the liver tumor segmentation.

HMGB1 augments cognitive impairment in sepsis-associated encephalopathy by binding to MD-2 and promoting NLRP3-induced neuroinflammation.

BACKGROUND: Sepsis-associated encephalopathy (SAE) always manifests with severe inflammatory symptoms and cognitive impairment. High mobility group box 1 (HMGB1) is a pro-inflammatory cytokine. In this study we investigated the role of HMGB1 in SAE. METHODS: An SAE mouse model was established through cecal ligation and puncture surgery and then injected with adenovirus short hairpin RNA (Ad-sh)-HMGB1 or Ad-sh-myeloid differentiation protein (MD-2). The cognitive impairment and pathological injury in mice of different groups were evaluated using the Morris water maze experiment, Y-maze test, tail suspension test, fear conditioning test, and haematoxylin-eosin staining. The expressions of HMGB1 (fully reduced and disulfide (ds)HMGB1), MD-2, and NLRP3 in SAE mice were determined. Then, levels of inflammatory cytokines were measured. The binding relation between HMGB1 and MD-2 was predicted and certified. Additionally, MD-2 was downregulated to verify the role of the binding of HMGB1 and MD-2 in neuroinflammation and cognitive impairment in SAE. RESULTS: Expressions of HMGB1, MD-2, NLRP3, and inflammatory cytokines were enhanced in the SAE mouse model, which were in parallel with impaired cognitive function. HMGB1 silencing resulted in downregulated NLRP3 expression and alleviated neuroinflammation and cognitive impairment in SAE mice. Mechanically, dsHMGB1 bound to MD-2 to activate NLRP3, thereby exacerbating neuroinflammation and cognitive impairment in SAE mice. The limited binding of HMGB1 and MD-2 downregulated NLRP3 expression to alleviate neuroinflammation and cognitive impairment in SAE mice. CONCLUSION: HMGB1 was overexpressed in SAE, and dsHMGB1 bound to MD-2 to activate NLRP3 inflammasome, inducing neuroinflammation and cognitive impairment in SAE.

Effects and mechanism of microRNA­218 against lung cancer.

Lung cancer is the most prevalent and observed type of cancer in Xuanwei County, Yunnan, South China. Lung cancer in this area is called Xuanwei lung cancer. However, its pathogenesis remains largely unknown. To date, a number of studies have shown that microRNA (miR)­218 functions as a tumor suppressor in multiple types of cancer. However, the role of miR­218 and its regulatory gene network in Xuanwei lung cancer have yet to be investigated. The current study identified that the expression levels of miR­218 in XWLC­05 cells were markedly lower compared with those in immortalized lung epithelial BEAS­2B cells. The present study also demonstrated that overexpression of miR­218 could decrease cell proliferation, invasion, viability and migration in Xuanwei lung cancer cell line XWLC­05 and NSCLC cell line NCI­H157. Additionally, the results revealed that overexpression of miR­218 could induce XWLC­05 and NCI­H157 cell apoptosis by arresting the cell cycle at G2/M phase. Finally, the present study demonstrated that overexpression of miR­218 could lead to a significant increase in phosphatase and tensin homolog (PTEN) and YY1 transcription factor (YY1), and a decrease in B­cell lymphoma 2 (BCL­2) and BMI1 proto­oncogene, polycomb ring finger (BMI­1) at the mRNA and protein level in XWLC­05 and NCI­H157 cell lines. However, we did not observe any remarkable difference in the roles of miR­218 and miR­218­mediated regulation of BCL­2, BMI­1, PTEN and YY1 expression in the progression of Xuanwei lung cancer. In conclusion, miR­218 could simultaneously suppress cell proliferation and tumor invasiveness and induce cell apoptosis by increasing PTEN and YY1 expression, while decreasing BCL­2 and BMI­1 in Xuanwei lung cancer. The results demonstrated that miR­218 might serve a vital role in tumorigenesis and progression of Xuanwei lung cancer and overexpression of miR­218 may be a novel approach for the treatment of Xuanwei lung cancer.

STAT1-induced upregulation of LINC00467 promotes the proliferation migration of lung adenocarcinoma cells by epigenetically silencing DKK1 to activate Wnt/ß-catenin signaling pathway.

Long non-coding RNAs (lncRNAs) have been reported as essential regulators in human cancers, including lung adenocarcinoma (LUAD). In the present study, we found that lncRNA long intergenic non-protein coding RNA 467 (LINC00467) was expressed higher in TCGA LUAD samples and predicted poor prognosis in LUAD patients. High expression of LINC00467 was further detected in LUAD cell lines. Functionally, high expression level of LINC00467 promoted LUAD cell proliferation and migration, indicating that LINC00467 exerted oncogenic functions in LUAD progression. Considering the upregulation of LINC00467 in LUAD, we further detected the activator of LINC00467 promoter. Combining with bioinformatics analysis and mechanism experiments, we determined that LINC00467 was activated by STAT1 in LUAD. Moreover, high expression of LINC00467 was found to be associated with the activation of Wnt/ß-catenin signaling pathway. Rescue assays demonstrated that dickkopf WNT signaling pathway inhibitor 1 (DKK1; an inhibitor of Wnt/ß-catenin signaling pathway) and Wnt/ß-catenin signaling involved in DKK1-mediated LUAD cell proliferation and migration. Furthermore, LINC00467 was located in the nucleus of LUAD cell lines and negatively regulated DKK1 in LUAD cells. Mechanistically, we determined that LINC00467 epigenetically silenced DKK1 by recruiting enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2) to DKK1 promoter. Collectively, we determined that STAT1-induced upregulation of LINC00467 promoted LUAD progression by epigenetically silencing DKK1 to activate Wnt/ß-catenin signaling pathway.