Malic enzyme 2 promotes the progression of hepatocellular carcinoma via increasing triglyceride production

Malic enzymes in cancer: Regulatory mechanisms, functions, and therapeutic implications

Malic enzymes (MEs) are metabolic enzymes that catalyze the oxidation of malate to pyruvate and NAD(P)H. While researchers have well established the physiological metabolic roles of MEs in organisms, recent research has revealed a link between MEs and carcinogenesis. This review collates evidence of the molecular mechanisms by which MEs promote cancer occurrence, including transcriptional regulation, post-transcriptional regulation, post-translational protein modifications, and protein-protein interactions. Additionally, we highlight the roles of MEs in reprogramming energy metabolism, suppressing senescence, and modulating the tumor immune microenvironment. We also discuss the involvement of these enzymes in mediating tumor resistance and how the development of novel small-molecule inhibitors targeting MEs might be a good therapeutic approach. Insights through this review are expected to provide a comprehensive understanding of the intricate relationship between MEs and cancer, while facilitating future research on the potential therapeutic applications of targeting MEs in cancer management.

Triglyceride-Glucose Index is an Independent Risk Factor for Hepatocellular Carcinoma Development in Patients with HBV-Related Liver Cirrhosis

Aim

This study aimed to explore the effects of the triglyceride-glucose (TyG) index on hepatocellular carcinoma (HCC) development in patients with hepatitis B virus (HBV)-related liver cirrhosis (LC).

Methods

A total of 242 patients with HBV-related LC were enrolled and followed-up. Logistic regression analysis was performed to investigate risk factors for HCC.

Results

The median follow-up time was 37 months (range: 6-123 months). At the end of the follow-up, 11 (11.3%) patients with compensated cirrhosis (CC) and 45 (31.0%) with decompensated cirrhosis (DC) developed HCC. The TyG index was higher in the HCC group than in the non-HCC group (P=0.05). Univariate analysis showed that age (P<0.01), DC (P<0.01), TyG index (P=0.08), albumin (ALB) level (P=0.05), platelet (PLT) count (P<0.01), and HBV DNA positivity (P<0.01) were associated with HCC development. Multivariate analysis revealed that age, DC, TyG index, PLT count, and HBV DNA positivity were independent risk factors for HCC development (P=0.01, 0.01, <0.01, 0.05, and <0.01, respectively). For patients with DC, multivariate logistic regression analysis revealed that age, TyG index, and HBV DNA positivity were independent risk factors for HCC development (all P<0.05). A new model encompassing age, DC, TyG, PLT, and positive HBV DNA had optimal predictive accuracy in patients with DC or CC, with a cutoff value of 0.197. The areas under the receiver operating characteristic curves (AUROCs) of the model for predicting HCC development in patients with LC, DC, and CC were 0.778, 0.721, and 0.783, respectively.

Conclusion

TyG index was identified as an independent risk factor for HCC development in patients with LC.

Identification of SNPs Associated with Goose Meat Quality Traits Using a Genome-Wide Association Study Approach

(1) Background: Goose meat is highly valued for its economic significance and vast market potential due to its desirable qualities, including a rich nutritional profile, tender texture, relatively low-fat content, and high levels of beneficial unsaturated fatty acids. However, there is an urgent need to improve goose breeding by identifying molecular markers associated with meat quality. (2) Methods: We evaluated meat quality traits, such as meat color, shear force (SF), cooking loss rate (CLR), and crude fat content (CFC), in a population of 215 male Sichuan white geese at 70 days of age. A GWAS was performed to identify potential molecular markers associated with goose meat quality. Furthermore, the selected SNPs linked to meat quality traits were genotyped using the MALDI-TOP MS method. (3) Results: A dataset of 2601.19 Gb of WGS data was obtained from 215 individuals, with an average sequencing depth of 10.89×. The GWAS revealed the identification of 43 potentially significant SNP markers associated with meat quality traits in the Sichuan white goose population. Additionally, 28 genes were identified as important candidate genes for meat quality. The gene enrichment analysis indicated a substantial enrichment of genes within a 1Mb vicinity of SNPs in both the protein digestion and absorption pathway and the Glycerolipid metabolism pathway. (4) Conclusion: This study provides valuable insights into the genetic and molecular mechanisms underlying goose meat quality traits, offering crucial references for molecular breeding in this field.

ME2 Promotes Hepatocellular Carcinoma Cell Migration through Pyruvate

Cancer metastasis is still a major challenge in clinical cancer treatment. The migration and invasion of cancer cells into surrounding tissues and blood vessels is the primary step in cancer metastasis. However, the underlying mechanism of regulating cell migration and invasion are not fully understood. Here, we show the role of malic enzyme 2 (ME2) in promoting human liver cancer cell lines SK-Hep1 and Huh7 cells migration and invasion. Depletion of ME2 reduces cell migration and invasion, whereas overexpression of ME2 increases cell migration and invasion. Mechanistically, ME2 promotes the production of pyruvate, which directly binds to β-catenin and increases β-catenin protein levels. Notably, pyruvate treatment restores cell migration and invasion of ME2-depleted cells. Our findings provide a mechanistic understanding of the link between ME2 and cell migration and invasion.

Increased Expression of the Mitochondrial Glucocorticoid Receptor Enhances Tumor Aggressiveness in a Mouse Xenograft Model

Mitochondria are important organelles for cellular physiology as they generate most of the energy requirements of the cell and orchestrate many biological functions. Dysregulation of mitochondrial function is associated with many pathological conditions, including cancer development. Mitochondrial glucocorticoid receptor (mtGR) is proposed as a crucial regulator of mitochondrial functions via its direct involvement in the regulation of mitochondrial transcription, oxidative phosphorylation (OXPHOS), enzymes biosynthesis, energy production, mitochondrial-dependent apoptosis, and regulation of oxidative stress. Moreover, recent observations revealed the interaction of mtGR with the pyruvate dehydrogenase (PDH), a key player in the metabolic switch observed in cancer, indicating direct involvement of mtGR in cancer development. In this study, by using a xenograft mouse model of mtGR-overexpressing hepatocarcinoma cells, we showed increased mtGR-associated tumor growth, which is accompanied by reduced OXPHOS biosynthesis, reduction in PDH activity, and alterations in the Krebs cycle and glucose metabolism, metabolic alterations similar to those observed in the Warburg effect. Moreover, autophagy activation is observed in mtGR-associated tumors, which further support tumor progression via increased precursors availability. Thus, we propose that increased mitochondrial localization of mtGR is associated with tumor progression possible via mtGR/PDH interaction, which could lead to suppression of PDH activity and modulation of mtGR-induced mitochondrial transcription that ends up in reduced OXPHOS biosynthesis and reduced oxidative phosphorylation versus glycolytic pathway energy production, in favor of cancer cells.

Clinical significance and immunogenomic landscape analysis of glycolysis-associated prognostic model to guide clinical therapy in hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is a common malignant tumor with a poor prognosis and high mortality rate worldwide. Glucose metabolism disorder is one of the most important characteristics of HCC. However, as the primary risk factors for the prognosis of HCC patients are unclear, the survival prognosis and therapy response of patients cannot be accurately predicted.

Methods

First, gene sets of 29 cancer hallmarks were collected from public databases. The z-score of various cancer hallmarks were quantitively analyzed by a single-sample gene set enrichment analysis (ssGSEA) of HCC patients. Next, a glycolysis-related gene signature (GRS) was constructed using a series of bioinformatics methods, which were used to predict the survival prognosis of HCC patients and the immunotherapy benefits. The prediction accuracy of the GRS was validated in different HCC cohorts and clinical subgroups. Additionally, a decision tree and nomogram were also established based on the GRS and other clinical variables. Finally, the genomic alterations and tumor immune microenvironment of the HCC patients were examined.

Results

Among the 29 cancer hallmarks, glycolysis was the most predominant risk factor for a poor prognosis in HCC. We subsequently constructed a novel GRS comprising 12 glycolysis-related genes. The high-GRS patients had a poorer survival prognosis than the low-GRS patients. The GRS exhibited a powerful ability to predict survival prognosis in different HCC cohorts and clinical feature subgroups. Additionally, the decision tree and nomogram aided in the risk stratification and prognosis evaluations of HCC patients. Further, we found that a high GRS was characterized by a severe tumor stage, pathological grade, and other clinical features. There were significant differences in the genomic alterations, immune cells, and immune checkpoints between the low- and high-GRS patients, especially in relation to the tumor protein p53 mutation and immunosuppressive cells. Notably, we also found that the GRS could be used to identify HCC patients who are more sensitive to chemotherapy and immunotherapy.

Conclusions

In summary, the GRS may be a useful tool for predicting the prognosis and guiding the clinical therapy of HCC patients.

Malic enzyme 2 promotes the progression of hepatocellular carcinoma via increasing triglyceride production

The incidence and mortality of hepatocellular carcinoma (HCC) are gradually increasing during the past years. Recently, some studies have reported that malic enzyme (ME) plays an important role in cancer development, while the involvement of ME2 in HCC remains still undetermined. Here, we demonstrated that ME2 played an oncogenic role in HCC. ME2 was overexpressed in HCC tissues. TCGA database showed that the ME2 transcript level was inversely associated with the survival of HCC patients. Loss‐of‐function and gain‐of‐function assays showed that ME2 promoted HCC cell growth and migration. Furthermore, the xenografted tumorigenesis of MHCC97H cells was retarded by ME2 knockdown. ME2 silencing also suppressed the cell cycle process and induced apoptosis. Mechanistically, ME2 potentiated triglyceride synthesis, inhibition of which suppressed the proliferation and migration. We propose that ME2 promotes HCC progression by increasing triglyceride production.