SREBP-1 has a prognostic role and contributes to invasion and metastasis in human hepatocellular carcinoma

Regulation and targeting of SREBP-1 in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is an increasing burden on global public health and is associated with enhanced lipogenesis, fatty acid uptake, and lipid metabolic reprogramming. De novo lipogenesis is under the control of the transcription factor sterol regulatory element-binding protein 1 (SREBP-1) and essentially contributes to HCC progression. Here, we summarize the current knowledge on the regulation of SREBP-1 isoforms in HCC based on cellular, animal, and clinical data. Specifically, we (i) address the overarching mechanisms for regulating SREBP-1 transcription, proteolytic processing, nuclear stability, and transactivation and (ii) critically discuss their impact on HCC, taking into account (iii) insights from pharmacological approaches. Emphasis is placed on cross-talk with the phosphatidylinositol-3-kinase (PI3K)-protein kinase B (Akt)-mechanistic target of rapamycin (mTOR) axis, AMP-activated protein kinase (AMPK), protein kinase A (PKA), and other kinases that directly phosphorylate SREBP-1; transcription factors, such as liver X receptor (LXR), peroxisome proliferator-activated receptors (PPARs), proliferator-activated receptor γ co-activator 1 (PGC-1), signal transducers and activators of transcription (STATs), and Myc; epigenetic mechanisms; post-translational modifications of SREBP-1; and SREBP-1-regulatory metabolites such as oxysterols and polyunsaturated fatty acids. By carefully scrutinizing the role of SREBP-1 in HCC development, progression, metastasis, and therapy resistance, we shed light on the potential of SREBP-1-targeting strategies in HCC prevention and treatment.

Molecular Genealogy of Metabolic-associated Hepatocellular Carcinoma

This review examines the latest epidemiological and molecular pathogenic findings of metabolic-associated hepatocellular carcinoma (HCC). Its increasing prevalence is a significant concern and reflects the growing burden of obesity and metabolic diseases, including metabolic dysfunction-associated steatotic liver disease, formerly known as nonalcoholic fatty liver disease, and type 2 diabetes. Metabolic-associated HCC has unique molecular abnormality and distinctive gene expression patterns implicating aberrations in bile acid, fatty acid metabolism, oxidative stress, and proinflammatory pathways. Furthermore, a notable frequency of single nucleotide polymorphisms in genes such as patatin-like phospholipase domain-containing 3, transmembrane 6 superfamily member 2, glucokinase regulator, and membrane-bound O-acyltransferase domain-containing 7 has been observed. The tumor immune microenvironment of metabolic-associated HCC is characterized by unique phenotypes of macrophages, neutrophils, and T lymphocytes. Additionally, the pathogenesis of metabolic-associated HCC is influenced by abnormal lipid metabolism, insulin resistance, and dysbiosis. In conclusion, deciphering the intricate interactions among metabolic processes, genetic predispositions, inflammatory responses, immune regulation, and microbial ecology is imperative for the development of novel therapeutic and preventative measures against metabolic-associated HCC.

Targeting metabolic reprogramming in hepatocellular carcinoma to overcome therapeutic resistance: A comprehensive review

Hepatocellular carcinoma (HCC) poses a heavy burden on human health with high morbidity and mortality rates. Systematic therapy is crucial for advanced and mid-term HCC, but faces a significant challenge from therapeutic resistance, weakening drug effectiveness. Metabolic reprogramming has gained attention as a key contributor to therapeutic resistance. Cells change their metabolism to meet energy demands, adapt to growth needs, or resist environmental pressures. Understanding key enzyme expression patterns and metabolic pathway interactions is vital to comprehend HCC occurrence, development, and treatment resistance. Exploring metabolic enzyme reprogramming and pathways is essential to identify breakthrough points for HCC treatment. Targeting metabolic enzymes with inhibitors is key to addressing these points. Inhibitors, combined with systemic therapeutic drugs, can alleviate resistance, prolong overall survival for advanced HCC, and offer mid-term HCC patients a chance for radical resection. Advances in metabolic research methods, from genomics to metabolomics and cells to organoids, help build the HCC metabolic reprogramming network. Recent progress in biomaterials and nanotechnology impacts drug targeting and effectiveness, providing new solutions for systemic therapeutic drug resistance. This review focuses on metabolic enzyme changes, pathway interactions, enzyme inhibitors, research methods, and drug delivery targeting metabolic reprogramming, offering valuable references for metabolic approaches to HCC treatment.

SREBP Regulation of Lipid Metabolism in Liver Disease, and Therapeutic Strategies

Sterol regulatory element-binding proteins (SREBPs) are master transcription factors that play a crucial role in regulating genes involved in the biogenesis of cholesterol, fatty acids, and triglycerides. As such, they are implicated in several serious liver diseases, including non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), fibrosis, and hepatocellular carcinoma (HCC). SREBPs are subject to regulation by multiple cofactors and critical signaling pathways, making them an important target for therapeutic interventions. In this review, we first introduce the structure and activation of SREBPs, before focusing on their function in liver disease. We examine the mechanisms by which SREBPs regulate lipogenesis, explore how alterations in these processes are associated with liver disease, and evaluate potential therapeutic strategies using small molecules, natural products, or herb extracts that target these pathways. Through this analysis, we provide new insights into the versatility and multitargets of SREBPs as factors in the modulation of different physiological stages of liver disease, highlighting their potential targets for therapeutic treatment.

Differential Proteome Profiling Analysis under Pesticide Stress by the Use of a Nano-UHPLC-MS/MS Untargeted Proteomic-Based Approach on a 3D-Developed Neurospheroid Model: Identification of Protein Interactions, Prognostic Biomarkers, and Potential Therapeutic Targets in Human IDH Mutant High-Grade Gliomas

High-grade gliomas represent the most common group of infiltrative primary brain tumors in adults associated with high invasiveness, agressivity, and resistance to therapy, which highlights the need to develop potent drugs with novel mechanisms of action. The aim of this study is to reveal changes in proteome profiles under stressful conditions to identify prognostic biomarkers and altered apoptogenic pathways involved in the anticancer action of human isocitrate dehydrogenase (IDH) mutant high-grade gliomas. Our protocol consists first of a 3D in vitro developing neurospheroid model and then treatment by a pesticide mixture at relevant concentrations. Furthermore, we adopted an untargeted proteomic-based approach with high-resolution mass spectrometry for a comparative analysis of the differentially expressed proteins between treated and nontreated spheroids. Our analysis revealed that the majority of altered proteins were key members in glioma pathogenesis, implicated in the cellular metabolism, biological regulation, binding, and catalytic and structural activity and linked to many cascading regulatory pathways. Our finding revealed that grade-IV astrocytomas promote the downstream of the mitogen-activated-protein-kinases/extracellular-signal-regulated kinase (MAPK1/ERK2) pathway involving massive calcium influx. The gonadotrophin-releasing-hormone signaling enhances MAKP activity and may serve as a negative feedback compensating regulator. Thus, our study can pave the way for effective new therapeutic and diagnostic strategies to improve the overall survival.

Lipid metabolism reprogramming in head and neck cancer

Lipid metabolism reprogramming is one of the most prominent metabolic anomalies in cancer, wherein cancer cells undergo dysregulation of lipid metabolism to acquire adequate energy, cell membrane building blocks, as well as signaling molecules essential for cell proliferation, survival, invasion, and metastasis. These adaptations enable cancer cells to effectively respond to challenges posed by the tumor microenvironment, leading to cancer therapy resistance and poor cancer prognosis. Head and neck cancer, ranking as the seventh most prevalent cancer, exhibits numerous abnormalities in lipid metabolism. Nevertheless, the precise role of lipid metabolic rewiring in head and neck cancer remains unclear. In line with the LIPID MAPS Lipid Classification System and cancer risk factors, the present review delves into the dysregulated molecules and pathways participating in the process of lipid uptake, biosynthesis, transportation, and catabolism. We also present an overview of the latest advancements in understanding alterations in lipid metabolism and how they intersect with the carcinogenesis, development, treatment, and prognosis of head and neck cancer. By shedding light on the significance of metabolic therapy, we aspire to improve the overall prognosis and treatment outcomes of head and neck cancer patients.

Palmitoylation-driven PHF2 ubiquitination remodels lipid metabolism through the SREBP1c axis in hepatocellular carcinoma

Palmitic acid (PA) is the most common fatty acid in humans and mediates palmitoylation through its conversion into palmitoyl coenzyme A. Although palmitoylation affects many proteins, its pathophysiological functions are only partially understood. Here we demonstrate that PA acts as a molecular checkpoint of lipid reprogramming in HepG2 and Hep3B cells. The zinc finger DHHC-type palmitoyltransferase 23 (ZDHHC23) mediates the palmitoylation of plant homeodomain finger protein 2 (PHF2), subsequently enhancing ubiquitin-dependent degradation of PHF2. This study also reveals that PHF2 functions as a tumor suppressor by acting as an E3 ubiquitin ligase of sterol regulatory element-binding protein 1c (SREBP1c), a master transcription factor of lipogenesis. PHF2 directly destabilizes SREBP1c and reduces SREBP1c-dependent lipogenesis. Notably, SREBP1c increases free fatty acids in hepatocellular carcinoma (HCC) cells, and the consequent PA induction triggers the PHF2/SREBP1c axis. Since PA seems central to activating this axis, we suggest that levels of dietary PA should be carefully monitored in patients with HCC.

EpCAM, Ki67, and ESM1 Predict Hepatocellular Carcinoma Recurrence After Liver Transplantation

Liver transplantation (LT) is a good therapeutic decision, cures hepatocellular carcinoma (HCC) and promotes survival of cases with unrespectable HCC based on the Milan criteria. HCC still recur after LT. Identifying high risk tissue markers that predict recurrence becomes important for LT decision-making. Little is known regarding use of tissue expression of epithelial cell adhesion molecule (EpCAM) to predict HCC recurrence. This study investigates the role of EpCAM, Ki67, and endothelial-cell-specific molecule-1 (ESM1) as immunohistochemical markers to predict HCC recurrence after LT. It included 52 explanted HCC tissues from Egyptian patients who had undergone LT for HCC according to Milan criteria. Immunohistochemical staining was done on paraffin-embedded formalin-fixed tissue sections. HCC recurrence occurred in 13.5% cases. Positive EpCAM expression in HCC, was significantly associated with HCC recurrence, ( P =0.011), achieving 71.43% sensitivity, 84.44% specificity and 78.8% accuracy in predicting recurrence. High Ki67 percentage was significantly associated with HCC recurrence, ( P =0.005), achieving 57.14% sensitivity, 86.67% specificity and 82.69% accuracy in predicting HCC recurrence. ESM1 showed significant association with HCC recurrence ( P =0.041), with 71.43% sensitivity, 71.11% specificity and 71.15% accuracy in predicting HCC recurrence. EpCAM score and Ki67 percentage showed positive correlation. In conclusion, it is suggested that large tumor size (≥3 cm), advanced pathologic staging and Ki67 could be stratified as high risk predictors of HCC recurrence after LT. Although higher classes of Child-Turcotte-Pugh classification, high serum alpha-fetoprotein, microvascular invasion, positive EpCAM and ESM1 are stratified as lower risk predictors of HCC recurrence after LT.

Non-alcoholic fatty liver disease and diabetes mellitus as growing aetiologies of hepatocellular carcinoma

Obesity-related complications such as non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes (T2D) are well-established risk factors for the development of hepatocellular carcinoma (HCC). This review provides insights into the molecular mechanisms that underlie the role of steatosis, hyperinsulinemia and hepatic inflammation in HCC development and progression. We focus on recent findings linking intracellular pathways and transcription factors that can trigger the reprogramming of hepatic cells. In addition, we highlight the role of enzymes in dysregulated metabolic activity and consequent dysfunctional signalling. Finally, we discuss the potential uses and challenges of novel therapeutic strategies to prevent and treat NAFLD/T2D-associated HCC.

Nonalcoholic steatohepatitis-associated hepatocarcinogenesis in mice fed a modified choline-deficient, methionine-lowered, L-amino acid-defined diet and the role of signal changes

Nonalcoholic steatohepatitis (NASH) can progress to cirrhosis and even hepatocellular carcinoma (HCC). The incidence of NASH-associated HCC is increasing, posing a serious public health threat. Unfortunately, the underlying pathological mechanisms, including the possible differences between neoplastic and non-neoplastic lesions, remain largely unknown. Previously, we reported a dietary mouse NASH model with a choline-deficient, methionine-lowered, L-amino-acid-defined, high-fat diet containing shortening without trans fatty acids (CDAA-HF-T[-]), which rapidly induces fibrosis and proliferative lesions in the liver. This study aimed to develop a mouse CDAA-HF-T(-) model capable of assessing NASH-associated hepatocarcinogenesis and identifying key signaling factors involved in its underlying mechanisms. Multiple large masses, histopathologically hepatocellular adenomas and carcinomas, and hemangiosarcomas were detected in the liver samples of mice fed CDAA-HF-T(-) for 52 or 63 weeks, along with highly advanced fibrosis and numerous foamy, phagocytic macrophages in the adjacent nontumoral area. Multiple metastatic nodules were found in the lungs of one of the animals, and lymphoid clusters were found in all CDAA-HF-T(-) group mice. In the Ingenuity Pathways Analysis of RNA expression data, the CDAA-HF-T(-) feeding revealed common signal changes in nontumoral and tumoral liver tissues, including increased IL-8 and RhoGTPases signaling and decreased lipid metabolism. Meanwhile, macrophage inflammatory protein 2 (MIP-2) expression levels were upregulated in nontumoral liver tissue from the end of Week 13 of CDAA-HF-T(-) feeding to the end of Week 63. On the other hand, MIP-2 was expressed on macrophages in non-tumor areas and hepatocytes in tumor areas. Therefore, the CDAA-HF-T(-) mouse model is useful for assessing NASH and NASH-associated hepatocarcinogenesis, and IL-8 signaling plays important roles in NASH-associated carcinogenesis and cirrhosis, but it may also play different roles in nontumoral liver tissue and tumorigenesis.

Dietary Coated Sodium Butyrate Ameliorates Hepatic Lipid Accumulation and Inflammation via Enhancing Antioxidative Function in Post-Peaking Laying Hens

During the aging process of laying hens, hepatic oxidative stress damage and lipid accumulation are prone to occur, leading to the deterioration of egg quality and a decline in production properties. This research was designed to explore the effects of different levels of coated sodium butyrate (CSB) addition on oxidation resistance, inflammatory reaction, lipid metabolism and hepatic oxidative damage-related gene expression in aged laying hens. A total of 720 healthy 52 weeks old Huafeng laying hens were arbitrarily divided into 5 groups of 6 replicates with 24 birds each and fed a basal diet supplemented with 0, 250, 500, 750 and 1000 mg/kg CSB for 8 weeks, respectively. The CSB quadratically upgraded GSH-Px activities and downgraded MDA content in the liver and serum. The LDL-C, NEFA and TG contents decreased quadratically in CSB groups and significantly reduced the fatty vacuoles as well as the formation of fat granules in the liver (p < 0.05). Meanwhile, the CSB quadratically upregulated the gene expression of IL-10, Nrf2 and HO1, but downregulated the gene expression of IFN-γ, TNF-α and Keap1 in a quadratic manner (p < 0.05). Moreover, the CSB quadratically degraded the mRNA level of fatty acid synthesis but increased the gene level of key enzymes of fatty acid catabolism (p < 0.05). In conclusion, dietary CSB supplementation has a favorable effect in protecting against liver injury and alleviating lipid accumulation and inflammation by enhancing hepatic antioxidative function in aged laying hens.

Lipid metabolism in tumor immunology and immunotherapy

Lipids are a diverse class of biomolecules that have been implicated in cancer pathophysiology and in an array of immune responses, making them potential targets for improving immune responsiveness. Lipid and lipid oxidation also can affect tumor progression and response to treatment. Although their importance in cellular functions and their potential as cancer biomarkers have been explored, lipids have yet to be extensively investigated as a possible form of cancer therapy. This review explores the role of lipids in cancer pathophysiology and describes how further understanding of these macromolecules could prompt novel treatments for cancer.

Total Flavonoids of Rhizoma Drynariae Mitigates Aflatoxin B1-Induced Liver Toxicity in Chickens via Microbiota-Gut-Liver Axis Interaction Mechanisms

Aflatoxin B1 (AFB1) is a common mycotoxin that widely occurs in feed and has severe hepatotoxic effects both in humans and animals. Total flavonoids of Rhizoma Drynaria (TFRD), a traditional Chinese medicinal herb, have multiple biological activities and potential hepatoprotective activity. This study investigated the protective effects and potential mechanisms of TFRD against AFB1-induced liver injury. The results revealed that supplementation with TFRD markedly lessened broiler intestinal permeability by increasing the expression of intestinal tight junction proteins, as well as correcting the changes in gut microbiota and liver damage induced by AFB1. Metabolomics analysis revealed that the alterations in plasma metabolites, especially taurolithocholic acid, were significantly improved by TFRD treatment in AFB1-exposed chickens. In addition, these metabolites were closely associated with [Ruminococcus], ACC, and GPX1, indicating that AFB1 may cause liver injury by inducing bile acid metabolism involving the microbiota–gut–liver axis. We further found that TFRD treatment markedly suppressed oxidative stress and hepatic lipid deposition, increased plasma glutathione (GSH) concentrations, and reversed hepatic ferroptosis gene expression. Collectively, these findings indicate that ferroptosis might contribute to the hepatotoxicity of AFB1-exposed chickens through the microbiota–gut–liver axis interaction mechanisms; furthermore, TFRD was confirmed as an herbal extract that could potentially antagonize mycotoxins detrimental effects.

Key events in cancer: Dysregulation of SREBPs

Lipid metabolism reprogramming is an important hallmark of tumor progression. Cancer cells require high levels of lipid synthesis and uptake not only to support their continued replication, invasion, metastasis, and survival but also to participate in the formation of biological membranes and signaling molecules. Sterol regulatory element binding proteins (SREBPs) are core transcription factors that control lipid metabolism and the expression of important genes for lipid synthesis and uptake. A growing number of studies have shown that SREBPs are significantly upregulated in human cancers and serve as intermediaries providing a mechanistic link between lipid metabolism reprogramming and malignancy. Different subcellular localizations, including endoplasmic reticulum, Golgi, and nucleus, play an indispensable role in regulating the cleavage maturation and activity of SREBPs. In this review, we focus on the relationship between aberrant regulation of SREBPs activity in three organelles and tumor progression. Because blocking the regulation of lipid synthesis by SREBPs has gradually become an important part of tumor therapy, this review also summarizes and analyzes several current mainstream strategies.

ncRNA-mediated fatty acid metabolism reprogramming in HCC

The challenges of hepatocellular carcinoma (HCC) pathogenesis, diagnosis, treatment, and prognosis evaluation are obvious. Hepatocyte-specific fatty acid (FA) metabolic reprogramming is an important marker of liver carcinogenesis and progression; elucidating its mechanism will help unravel the complexity of HCC pathogenesis. Noncoding RNAs (ncRNAs) play important roles in HCC development. Moreover, ncRNAs are important mediators of FA metabolism and are directly involved in the reprogramming of FA metabolism in HCC cells. Here we review significant new advances in understanding the mechanisms regulating HCC metabolism by focusing on ncRNA-mediated post-translational modifications of metabolic enzymes, metabolism-related transcription factors, and other proteins in associated signaling pathways. We also discuss the great therapeutic potential of targeting ncRNA-mediated FA metabolism reprogramming in HCC.

Sterol regulatory element binding transcription factor 1 promotes proliferation and migration in head and neck squamous cell carcinoma

Background

Sterol-regulatory element-binding protein 1 (SREBP1) is a transcription factor involved in lipid metabolism that is encoded by sterol regulatory element binding transcription factor 1(SREBF1). SREBP1 overexpression is associated with the progression of several human tumors; however, the role of SREBP1 in head and neck squamous cell carcinoma (HNSC) remains unclear.

Methods

SREBF1 expression in pan-cancer was analyzed using the Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) data, and the association between SREBF1 expression and clinical characteristics of HNSC patients was examined using the UALCAN database. Enrichment analysis of SREBF1-related genes was performed using the Cluster Profiler R package. TCGA database was used to investigate the relationship between immune cell infiltration and SREBF1 expression. CCK-8, flow cytometry, and wound healing assays were performed to investigate the effect of SREBF1 knockdown on the proliferation and migration of HNSC cells.

Results

SREBF1 was significantly upregulated in several tumor tissues, including HNSC, and SREBF1 overexpression was positively correlated with sample type, cancer stage, tumor grade, and lymph node stage in HNSC patients. Gene enrichment analysis revealed that SREBF1 is associated with DNA replication and homologous recombination. SREBF1 upregulation was positively correlated with the infiltration of cytotoxic cells, B cells, T cells, T helper cells, and NK CD56 bright cells in HNSC. Knockdown of SREBF1 inhibited the proliferation and migration of HNSC cells (Hep2 and TU212) and induced apoptosis by downregulating the expression of steroidogenic acute regulatory protein-related lipid transfer 4 (STARD4).

Conclusions

SREBF1 may promote HNSC proliferation, migration and inhibit apoptosis by upregulating STARD4 and affecting the level of immune cell infiltration.

The Emerging Role of Tumor Microenvironmental Stimuli in Regulating Metabolic Rewiring of Liver Cancer Stem Cells

Primary liver cancer (PLC) is one of the most devastating cancers worldwide. Extensive phenotypical and functional heterogeneity is a cardinal hallmark of cancer, including PLC, and is related to the cancer stem cell (CSC) concept. CSCs are responsible for tumor growth, progression, relapse and resistance to conventional therapies. Metabolic reprogramming represents an emerging hallmark of cancer. Cancer cells, including CSCs, are very plastic and possess the dynamic ability to constantly shift between different metabolic states depending on various intrinsic and extrinsic stimuli, therefore amplifying the complexity of understanding tumor heterogeneity. Besides the well-known Warburg effect, several other metabolic pathways including lipids and iron metabolism are altered in PLC. An increasing number of studies supports the role of the surrounding tumor microenvironment (TME) in the metabolic control of liver CSCs. In this review, we discuss the complex metabolic rewiring affecting liver cancer cells and, in particular, liver CSCs. Moreover, we highlight the role of TME cellular and noncellular components in regulating liver CSC metabolic plasticity. Deciphering the specific mechanisms regulating liver CSC-TME metabolic interplay could be very helpful with respect to the development of more effective and innovative combinatorial therapies for PLC treatment.

Type XXVIII Collagen Regulates Renal Interstitial Fibrosis and Epithelial-Mesenchymal Transition by SREBP1-Mediated HKDC1 Expression

Background. A novel collagen called type XXVIII collagen (COL28) is involved in cancer and lung fibrosis. Preliminary data showed that renal tubular epithelial cells could proliferate, migrate, and undergo an epithelial-mesenchymal transition (EMT) when COL28 was overexpressed; however, it is still unknown how this occurs and what the underlying mechanism is. Methods. We analyzed the differential expression of genes (DEGs) in the stable COL28 overexpression HK-2 cell lines by RNA-sequencing analysis, before which Gene Ontology (GO) and Kyoto Encyclopedia of Gene and Genomes (KEGG) analyses were performed. Genes related to COL28 promoting HK-2 cell proliferation and EMT were screened and verified. By using western blot and immunofluorescence, the effects of COL28 on the expression of α-SMA, E-cadherin, Snail, HKDC1, and SREBP1 were detected. The effect of COL28 overexpression on renal fibrosis in unilateral ureteral obstruction (UUO) mice was detected by H&E and Masson staining. HKDC1 interference agent was synthesized and transfected into the HK-2 cell line stably overexpressing COL28. In HK-2 cells, the effects of HKDC1 interference on the expression of α-SMA, E-cadherin, and Snail were detected. Results. We screened and verified that HKDC1 was related to COL28 and promoted HK-2 cell proliferation and EMT. WB showed that in HK-2 cells, COL28 overexpression increased α-SMA, Snail, HKDC1, and SREBP1 expressions and decreased E-cadherin expression. Overexpression of COL28 aggravated renal interstitial fibrosis in UUO mice; upregulated α-SMA, Snail, HKDC1, and SREBP1 expressions; and decreased the E-cadherin protein expression in UUO mice. Interference of HKDC1 expression promoted the E-cadherin protein expression while inhibiting α-SMA, Snail, HKDC1, and SREBP1 protein expressions. Conclusion. Overexpression of COL28 can aggravate renal interstitial fibrosis by encouraging renal tubular epithelial cells to undergo EMT, and interference with HKDC1 expression can alleviate fibrosis by reversing EMT induced by COL28 overexpression.

Transcriptome Analysis Reveals That SREBP Modulates a Large Repertoire of Genes Involved in Key Cellular Functions in Penaeus vannamei, although the Majority of the Dysregulated Genes Are Unannotated

Sterol regulatory element-binding proteins (SREBPs) play vital roles in fatty acid metabolism and other metabolic processes in mammals. However, in penaeid shrimp, the repertoire of genes modulated by SREBP is unknown. Here, RNA interference-mediated knockdown followed by transcriptome sequencing on the Illumina Novaseq 6000 platform was used to explore the genes modulated by SREBP in Penaeus vannamei hepatopancreas. A total of 706 differentially expressed genes (DEGs) were identified, out of which 282 were upregulated and 424 downregulated. Although gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed that most of the downregulated DEGs were involved in physiological processes related to immunity, metabolism, and cellular signaling pathways, many of the dysregulated genes have uncharacterized functions. While most of the dysregulated genes were annotated in metabolic processes, such as carbohydrate metabolism, lipid metabolism, signal transduction, and immune system, a large number (42.21%) are uncharacterized. Collectively, our current data revealed that SREBP modulates many genes involved in crucial physiological processes, such as energy metabolism, immune response, and cellular signaling pathways, as well as numerous genes with unannotated functions, in penaeid shrimp. These findings indicated that our knowledge of the repertoire of genes modulated by SREBP in shrimp lags behind that of mammals, probably due to limited research or because the complete genome of P. vannamei has just been sequenced.

The role of lipids in cancer progression and metastasis

Lipids have essential biological functions in the body (e.g., providing energy storage, acting as a signaling molecule, and being a structural component of membranes); however, an excess of lipids can promote tumorigenesis, colonization, and metastatic capacity of tumor cells. To metastasize, a tumor cell goes through different stages that require lipid-related metabolic and structural adaptations. These adaptations include altering the lipid membrane composition for invading other niches and overcoming cell death mechanisms and promoting lipid catabolism and anabolism for energy and oxidative stress protective purposes. Cancer cells also harness lipid metabolism to modulate the activity of stromal and immune cells to their advantage and to resist therapy and promote relapse. All this is especially worrying given the high fat intake in Western diets. Thus, metabolic interventions aiming to reduce lipid availability to cancer cells or to exacerbate their metabolic vulnerabilities provide promising therapeutic opportunities to prevent cancer progression and treat metastasis.

Litchi flower essential oil balanced lipid metabolism through the regulation of DAF-2/IIS, MDT-15/SBP-1, and MDT-15/NHR-49 pathway

Many litchi flowers are discarded in China every year. The litchi flower is rich in volatile compounds and exhibits strong anti-obesity activity. Litchi flower essential oil (LFEO) was extracted by the continuous phase transformation device (CPTD) independently developed by our research group to recycle the precious material resources in litchi flowers. However, its fat-reducing effect and mechanism remain unclear. Employing Caenorhabditis elegans as a model, we found that LFEO significantly reduced fat storage and triglyceride (TG) content in normal, glucose-feeding, and high-fat conditions. LFEO significantly reduced body width in worms and significantly decreased both the size and number of lipid droplets in ZXW618. LFEO treatment did not affect energy intake but increased energy consumption by enhancing the average speed of worms. Further, LFEO might balance the fat metabolism in worms by regulating the DAF-2/IIS, sbp-1/mdt-15, and nhr-49/mdt-15 pathways. Moreover, LFEO might inhibit the expression of the acs-2 gene through nhr-49 and reduce β-oxidation activity. Our study presents new insights into the role of LFEO in alleviating fat accumulation and provides references for the large-scale production of LFEO to promote the development of the litchi circular economy.

Targeting SREBP-1-Mediated Lipogenesis as Potential Strategies for Cancer

Sterol regulatory element binding protein-1 (SREBP-1), a transcription factor with a basic helix–loop–helix leucine zipper, has two isoforms, SREBP-1a and SREBP-1c, derived from the same gene for regulating the genes of lipogenesis, including acetyl-CoA carboxylase, fatty acid synthase, and stearoyl-CoA desaturase. Importantly, SREBP-1 participates in metabolic reprogramming of various cancers and has been a biomarker for the prognosis or drug efficacy for the patients with cancer. In this review, we first introduced the structure, activation, and key upstream signaling pathway of SREBP-1. Then, the potential targets and molecular mechanisms of SREBP-1-regulated lipogenesis in various types of cancer, such as colorectal, prostate, breast, and hepatocellular cancer, were summarized. We also discussed potential therapies targeting the SREBP-1-regulated pathway by small molecules, natural products, or the extracts of herbs against tumor progression. This review could provide new insights in understanding advanced findings about SREBP-1-mediated lipogenesis in cancer and its potential as a target for cancer therapeutics.

Rhamnolipids Regulate Lipid Metabolism, Immune Response, and Gut Microbiota in Rats

Objectives

Gut microbes influence lipid metabolism and immune responses that are key features of metabolic disorders. This study examined effects of bacterial rhamnolipids (RLS) on lipid metabolism, immune response, and gut microbiota in rats.

Methods

Twenty-four Sprague-Dawley rats were randomly divided into three groups and gavage-fed for seven weeks with normal saline (NCO group), 50 mg/kg bw RLS (RLS1 group), and 100 mg/kg bw RLS (RLS2 group).

Results

Compared with those of the NCO group, the RLS1 and RLS2 groups showed significantly decreased fat weight, relative fat weight, and adipocyte size (P < 0.05). Furthermore, RLS1 and RLS2 significantly decreased concentrations of triglycerides, low-density lipoprotein-cholesterol, and non-esterified fatty acids and increased high-density lipoprotein-cholesterol levels (P < 0.05). However, the total cholesterol content among the three groups (P > 0.05) were not significantly different. Serum concentrations of interleukin-1β, interleukin-6, and tumor necrosis factor-α were significantly lower in the RLS2 group than those in the NCO group (P < 0.05). The relative mRNA expression of fatty acid synthase was significantly decreased, while those of carnitine palmitoyltransferase-1, carnitine palmitoyltransferase-2, and peroxisome proliferator-activated receptor-gamma coactivator-1α were significantly increased in the RLS2 group compared with those in the NCO group (P < 0.05). Moreover, the relative abundances of Lactobacillus, Roseburia, Ruminococcus-1, and Parabacteroides were significantly higher in the RLS2 group than those in the NCO group (P < 0.05).

Conclusion

Our findings suggest that RLS reduces fat deposition, inhibits inflammation, regulates intestinal flora, and promotes the proliferation of beneficial bacteria in rats.

Ammonia stimulates SCAP/Insig dissociation and SREBP-1 activation to promote lipogenesis and tumour growth

Tumorigenesis is associated with elevated glucose and glutamine consumption, but how cancer cells can sense their levels to activate lipid synthesis is unknown. Here, we reveal that ammonia, released from glutamine, promotes lipogenesis via activation of sterol regulatory element-binding proteins (SREBPs), endoplasmic reticulum-bound transcription factors that play a central role in lipid metabolism. Ammonia activates the dissociation of glucose-regulated, N-glycosylated SREBP-cleavage-activating protein (SCAP) from insulin-inducible gene protein (Insig), an endoplasmic reticulum-retention protein, leading to SREBP translocation and lipogenic gene expression. Notably, 25-hydroxycholesterol blocks ammonia to access its binding site on SCAP. Mutating aspartate D428 to alanine prevents ammonia binding to SCAP, abolishes SREBP-1 activation and suppresses tumour growth. Our study characterizes the unknown role, opposite to sterols, of ammonia as a key activator that stimulates SCAP-Insig dissociation and SREBP-1 activation to promote tumour growth and demonstrates that SCAP is a critical sensor of glutamine, glucose and sterol levels to precisely control lipid synthesis.

Metabolic dysregulation and emerging therapeutical targets for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is an aggressive human cancer with increasing incidence worldwide. Multiple efforts have been made to explore pharmaceutical therapies to treat HCC, such as targeted tyrosine kinase inhibitors, immune based therapies and combination of chemotherapy. However, limitations exist in current strategies including chemoresistance for instance. Tumor initiation and progression is driven by reprogramming of metabolism, in particular during HCC development. Recently, metabolic associated fatty liver disease (MAFLD), a reappraisal of new nomenclature for non-alcoholic fatty liver disease (NAFLD), indicates growing appreciation of metabolism in the pathogenesis of liver disease, including HCC, thereby suggesting new strategies by targeting abnormal metabolism for HCC treatment. In this review, we introduce directions by highlighting the metabolic targets in glucose, fatty acid, amino acid and glutamine metabolism, which are suitable for HCC pharmaceutical intervention. We also summarize and discuss current pharmaceutical agents and studies targeting deregulated metabolism during HCC treatment. Furthermore, opportunities and challenges in the discovery and development of HCC therapy targeting metabolism are discussed.

Role of Lipogenesis Rewiring in Hepatocellular Carcinoma

Metabolic rewiring is one of the hallmarks of cancer. Altered de novo lipogenesis is one of the pivotal metabolic events deregulated in cancers. Sterol regulatory element-binding transcription factor 1 (SREBP1) controls the transcription of major enzymes involved in de novo lipogenesis, including ACLY, ACACA, FASN, and SCD. Studies have shown the increased de novo lipogenesis in human hepatocellular carcinoma (HCC) samples. Multiple mechanisms, such as activation of the AKT/mechanistic target of rapamycin (mTOR) pathway, lead to high SREBP1 induction and the coordinated enhanced expression of ACLY, ACACA, FASN, and SCD genes. Subsequent functional analyses have unraveled these enzymes' critical role(s) and the related de novo lipogenesis in hepatocarcinogenesis. Importantly, targeting these molecules might be a promising strategy for HCC treatment. This paper comprehensively summarizes de novo lipogenesis rewiring in HCC and how this pathway might be therapeutically targeted.

Targeting the PI3K/Akt/mTOR Pathway in Hepatocellular Carcinoma

Despite advances in the treatment of cancers through surgical procedures and new pharmaceuticals, the treatment of hepatocellular carcinoma (HCC) remains challenging as reflected by low survival rates. The PI3K/Akt/mTOR pathway is an important signaling mechanism that regulates the cell cycle, proliferation, apoptosis, and metabolism. Importantly, deregulation of the PI3K/Akt/mTOR pathway leading to activation is common in HCC and is hence the subject of intense investigation and the focus of current therapeutics. In this review article, we consider the role of this pathway in the pathogenesis of HCC, focusing on its downstream effectors such as glycogen synthase kinase-3 (GSK-3), cAMP-response element-binding protein (CREB), forkhead box O protein (FOXO), murine double minute 2 (MDM2), p53, and nuclear factor-κB (NF-κB), and the cellular processes of lipogenesis and autophagy. In addition, we provide an update on the current ongoing clinical development of agents targeting this pathway for HCC treatments.

Abnormal Metabolism in the Progression of Nonalcoholic Fatty Liver Disease to Hepatocellular Carcinoma: Mechanistic Insights to Chemoprevention

Nonalcoholic fatty liver disease (NAFLD) is on the rise and becoming a major contributor to the development of hepatocellular carcinoma (HCC). Reasons for this include the rise in obesity and metabolic syndrome in contrast to the marked advances in prevention and treatment strategies of viral HCC. These shifts are expected to rapidly propel this trend even further in the coming decades, with NAFLD on course to become the leading etiology of end-stage liver disease and HCC. No Food and Drug Administration (FDA)-approved medications are currently available for the treatment of NAFLD, and advances are desperately needed. Numerous medications with varying mechanisms of action targeting liver steatosis and fibrosis are being investigated including peroxisome proliferator-activated receptor (PPAR) agonists and farnesoid X receptor (FXR) agonists. Additionally, drugs targeting components of metabolic syndrome, such as antihyperglycemics, have been found to affect NAFLD progression and are now being considered in the treatment of these patients. As NAFLD drug discovery continues, special attention should be given to their relationship to HCC. Several mechanisms in the pathogenesis of NAFLD have been implicated in hepatocarcinogenesis, and therapies aimed at NAFLD may additionally harbor independent antitumorigenic potential. This approach may provide novel prevention and treatment strategies.

Polycationic cyclodextrin nanoparticles induce apoptosis and affect antitumoral activity in HepG2 cell line: An evaluation at the molecular level

Hepatocellular carcinoma (HCC) is a highly metastatic primary liver cancer generating molecular alterations that end up escaping the apoptotic machinery and conferring multidrug resistance. Targeted medicines with increased and selective cytotoxicity and minimal drug resistance are essential for the treatment of HCC. In this study, a self-assembled polycationic (PC) amphiphilic β-cyclodextrin (βCDC6) nanoparticle formulation was characterized and its efficacy over HCC cell line HepG2 was evaluated in terms of cytotoxicity, apoptotic potential, chemosensitivity and mitochondrial balance utilizing biochemical, gene expression and proteomic approaches without encapsulating an anti-neoplastic agent. Blank PC βCDC6 exerted an anti-proliferative effect on 3D multicellular HepG2 spheroid tumors. These nanoparticles were able to trigger apoptosis proved by caspase 3/7 activity, gene expression and flow cytometry studies. The subjection of PC restored the chemosensitivity of HepG2 cells by suppressing the function of p-glycoprotein. The proteomic studies with Q-TOF LC/MS revealed 73 proteins that are aberrantly encoded after cells were treated with the blank PC. Metabolomic analysis further confirmed the shift in certain biological pathways. Thus, we confirmed that the hepatocellular carcinoma-targeting βCDC6 PC nanoparticles induce apoptosis, lower the rate of cell proliferation, hinder multidrug resistance and they are convenient carriers for eventual therapeutic administrations in HCC patients.

ACSL4 reprograms fatty acid metabolism in hepatocellular carcinoma via c-Myc/SREBP1 pathway

Lipid metabolic reprogramming plays a pivotal role in hepatocellular carcinoma (HCC) development, but the underlying mechanisms are incompletely characterized. Long chain acyl CoA synthetase 4 (ACSL4), a member of acyl-CoA synthetases (ACS) family, has been identified as a novel marker of alpha-fetoprotein-high subtype HCC and as an oncogene. Here, we identified a new function of ACSL4 in HCC lipid metabolism. ACSL4 can modulate de novo lipogenesis by accumulating intracellular triglycerides, cholesterols, and lipid droplets in HCC. Mechanistically, ACSL4 upregulates the master lipogenesis regulator sterol regulatory element binding protein 1 (SREBP1) and its downstream lipogenic enzymes in HCC cells via c-Myc. Moreover, SREBP1 is crucial for ACSL4-mediated regulation of lipogenesis as well as HCC cell proliferation and metastasis, as SREBP1 overexpression rescues lipogenic deficiency and decreased oncogenic capabilities associated with ACSL4 suppression in vitro and in vivo. Clinically, our data showed that the expression of ACSL4 was positively correlated with that of SREBP1 in HCC patients, and the combinational biomarkers showed strong predictive value for HCC. Together, our findings uncover a new mechanism by which ACSL4 modulates aberrant lipid metabolism and promotes the progression of HCC.

Targeting the alternative bile acid synthetic pathway for metabolic diseases

The gut microbiota is profoundly involved in glucose and lipid metabolism, in part by regulating bile acid (BA) metabolism and affecting multiple BA-receptor signaling pathways. BAs are synthesized in the liver by multi-step reactions catalyzed via two distinct routes, the classical pathway (producing the 12α-hydroxylated primary BA, cholic acid), and the alternative pathway (producing the non-12α-hydroxylated primary BA, chenodeoxycholic acid). BA synthesis and excretion is a major pathway of cholesterol and lipid catabolism, and thus, is implicated in a variety of metabolic diseases including obesity, insulin resistance, and nonalcoholic fatty liver disease. Additionally, both oxysterols and BAs function as signaling molecules that activate multiple nuclear and membrane receptor-mediated signaling pathways in various tissues, regulating glucose, lipid homeostasis, inflammation, and energy expenditure. Modulating BA synthesis and composition to regulate BA signaling is an interesting and novel direction for developing therapies for metabolic disease. In this review, we summarize the most recent findings on the role of BA synthetic pathways, with a focus on the role of the alternative pathway, which has been under-investigated, in treating hyperglycemia and fatty liver disease. We also discuss future perspectives to develop promising pharmacological strategies targeting the alternative BA synthetic pathway for the treatment of metabolic diseases.

Risk Factors, Pathogenesis, and Strategies for Hepatocellular Carcinoma Prevention: Emphasis on Secondary Prevention and Its Translational Challenges

Hepatocellular carcinoma (HCC) is a leading cause of cancer-associated mortality globally. Given the limited therapeutic efficacy in advanced HCC, prevention of HCC carcinogenesis could serve as an effective strategy. Patients with chronic fibrosis due to viral or metabolic etiologies are at a high risk of developing HCC. Primary prevention seeks to eliminate cancer predisposing risk factors while tertiary prevention aims to prevent HCC recurrence. Secondary prevention targets patients with baseline chronic liver disease. Various epidemiological and experimental studies have identified candidates for secondary prevention-both etiology-specific and generic prevention strategies-including statins, aspirin, and anti-diabetic drugs. The introduction of multi-cell based omics analysis along with better characterization of the hepatic microenvironment will further facilitate the identification of targets for prevention. In this review, we will summarize HCC risk factors, pathogenesis, and discuss strategies of HCC prevention. We will focus on secondary prevention and also discuss current challenges in translating experimental work into clinical practice.

Anti-Cancer Effects of Green Tea Epigallocatchin-3-Gallate and Coffee Chlorogenic Acid

Tea and coffee are consumed worldwide and epidemiological and clinical studies have shown their health beneficial effects, including anti-cancer effects. Epigallocatechin gallate (EGCG) and chlorogenic acid (CGA) are the major components of green tea polyphenols and coffee polyphenols, respectively, and believed to be responsible for most of these effects. Although a large number of cell-based and animal experiments have provided convincing evidence to support the anti-cancer effects of green tea, coffee, EGCG, and CGA, human studies are still controversial and some studies have suggested even an increased risk for certain types of cancers such as esophageal and gynecological cancers with green tea consumption and bladder and lung cancers with coffee consumption. The reason for these inconsistent results may have been arisen from various confounding factors. Cell-based and animal studies have proposed several mechanisms whereby EGCG and CGA exert their anti-cancer effects. These components appear to share the common mechanisms, among which one related to reactive oxygen species is perhaps the most attractive. Meanwhile, EGCG and CGA have also different target molecules which might explain the site-specific differences of anti-cancer effects found in human studies. Further studies will be necessary to clarify what is the mechanism to cause such differences between green tea and coffee.

NASH, Fibrosis and Hepatocellular Carcinoma: Lipid Synthesis and Glutamine/Acetate Signaling

Primary liver cancer is predicted to be the sixth most common cancer and the fourth leading cause of cancer mortality worldwide. Recent studies identified nonalcoholic fatty liver disease (NAFLD) as the underlying cause in 13-38.2% of patients with hepatocellular carcinoma unrelated to viral hepatitis and alcohol abuse. NAFLD progresses to nonalcoholic steatohepatitis (NASH), which increases the risk for the development of liver fibrosis, cirrhosis, and hepatocellular carcinoma. NAFLD is characterized by dysregulation of lipid metabolism. In addition, lipid metabolism is effected not only in NAFLD, but also in a broad range of chronic liver diseases and tumor development. Cancer cells manipulate a variety of metabolic pathways, including lipid metabolism, in order to build up their own cellular components. Identifying tumor dependencies on lipid metabolism would provide options for novel targeting strategies. This review article summarizes the research evidence on metabolic reprogramming and focuses on lipid metabolism in NAFLD, NASH, fibrosis, and cancer. As alternative routes of acetyl-CoA production for fatty acid synthesis, topics on glutamine and acetate metabolism are included. Further, studies on small compound inhibitors targeting lipid metabolism are discussed. Understanding reprogramming strategies in liver diseases, as well as the visualization of the metabolism reprogramming networks, could uncover novel therapeutic options.

Upregulation of PD-L1 expression promotes epithelial-to-mesenchymal transition in sorafenib-resistant hepatocellular carcinoma cells

Background

The epithelial-to-mesenchymal transition (EMT) status is associated with programmed death-1 ligand 1 (PD-L1) expression in various cancers. However, the role and molecular mechanism of PD-L1 in the EMT of sorafenib-resistant hepatocellular carcinoma (HCC) cells remain elusive. In this study, we aimed to investigate the regulation of PD-L1 on the EMT in sorafenib-resistant HCC cells.

Methods

Initially, the sorafenib-resistant HCC cell lines HepG2 SR and Huh7 SR were established. Western-blot assays were used to detect the expression of PD-L1, E-cadherin, and N-cadherin. The intervention and overexpression of PD-L1 were used to explore the role of PD-L1 in the regulation of EMT in HepG2 SR and Huh7 SR cells. Cell migration and invasion were assessed by transwell assays. PD-L1 or Sterol regulatory element-binding protein 1 (SREBP-1) overexpression and knock-down were performed in order to study the mechanism of PD-L1 in sorafenib-resistant HCC cells.

Results

PD-L1 expression was upregulated, whereas E-cadherin levels were downregulated and N-cadherin expression was increased in HepG2 SR and Huh7 SR cells. The cell viabilities of HepG2 and Huh7 cells were lower than those of HepG2 SR and Huh7 SR cells. PD-L1 overexpression reduced E-cadherin expression and increased N-cadherin levels, whereas PD-L1 knock-down increased E-cadherin expression and decreased N-cadherin expression. PD-L1 expression promoted EMT and the migratory and invasive abilities of HepG2 SR and Huh7 SR cells. PD-L1 promoted the EMT of sorafenib-resistant HCC cells via the PI3K/Akt pathway by activating SREBP-1 expression in HepG2 SR and Huh7 SR cells.

Conclusions

The findings reveal that PD-L1 expression promotes EMT of sorafenib-resistant HCC cells.

The lipogenic LXR-SREBF1 signaling pathway controls cancer cell DNA repair and apoptosis and is a vulnerable point of malignant tumors for cancer therapy

Cancer cells are defective in DNA repair, so they experience increased DNA strand breaks, genome instability, gene mutagenesis, and tumorigenicity; however, multiple classic DNA repair genes and pathways are strongly activated in malignant tumor cells to compensate for the DNA repair deficiency and gain an apoptosis resistance. The mechanisms underlying this phenomenon in cancer are unclear. We speculate that a key DNA repair gene or signaling pathway in cancer has not yet been recognized. Here, we show that the lipogenic liver X receptor (LXR)-sterol response element binding factor-1 (SREBF1) axis controls the transcription of a key DNA repair gene polynucleotide kinase/phosphatase (PNKP), thereby governing cancer cell DNA repair and apoptosis. Notably, the PNKP levels were significantly reduced in 95% of human pancreatic cancer (PC) patients, particularly deep reduction for sixfold in all of the advanced-stage PC cases. PNKP is also deficient in three other types of cancer that we examined. In addition, the expression of LXRs and SREBF1 was significantly reduced in the tumor tissues from human PC patients compared with the adjacent normal tissues. The newly identified LXR-SREBF1-PNKP signaling pathway is deficient in PC, and the defect in the pathway contributes to the DNA repair deficiency in the cancer. Strikingly, further diminution of the vulnerable LXR-SREBF1-PNKP signaling pathway using a small molecule triptonide, a new LXR antagonist identified in this investigation, at a concentration of 8 nM robustly activated tumor-suppressor p53 and readily elevated cancer cell DNA strand breaks over an apoptotic threshold, and selectively induced PC cell apoptosis, resulting in almost complete elimination of tumors in xenograft mice without obvious complications. Our findings provide new insight into DNA repair and apoptosis in cancer, and offer a new platform for developing novel anticancer therapeutics.

UBC12-mediated SREBP-1 neddylation worsens metastatic tumor prognosis

Activation of sterol regulatory element-binding protein 1 (SREBP-1), a master lipogenic transcription factor, is associated with cancer metabolism and metabolic disorders. Neddylation, the process of adding NEDD8 to its substrate, contributes to diverse biological processes. Here, we identified SREBP-1 as a substrate for neddylation by UBC12 and explored its impact on tumor aggressiveness. In cell-based assays, SREBP-1 neddylation prolonged SREBP-1 stability with a decrease in ubiquitination. Consequently, NEDD8 overexpression facilitated proliferation, migration, and invasion of SK-Hep1 liver tumor cells. MLN4924 (an inhibitor of the NEDD8-activating enzyme-E1) treatment or UBC12 knockdown prevented SREBP-1 neddylation and tumor cell phenotype change. This effect was corroborated in an in vivo xenograft model. In human specimens, SREBP-1, UBC12, and NEDD8 were all upregulated in hepatocellular carcinoma (HCC) compared to nontumorous regions. Moreover, SREBP-1 levels positively correlated with UBC12. In GEO database analyses, SREBP-1 levels were greater in metastatic HCC samples accompanying UBC12 upregulation. In HCC analysis, tumoral SREBP-1 and UBC12 levels discriminated overall patient survival rates. Additionally, MLN4924 treatment destabilized SREBP-1 in MDA-MB-231 breast cancer cells and in the tumor cell xenograft. SREBP-1 and UBC12 were also highly expressed in human breast cancer tissues. Moreover, most breast cancers with lymph node metastasis displayed predominant SREBP-1 and UBC12 expressions, which compromised overall patient survival rates. In summary, SREBP-1 is neddylated by UBC12, which may contribute to HCC and breast cancer aggressiveness through SREBP-1 stabilization, and these events can be intervented by MLN4924 therapy. Our findings may also provide potential reliable prognostic markers for tumor metastasis.

Lipid Metabolism in Development and Progression of Hepatocellular Carcinoma

: Metabolic reprogramming is critically involved in the development and progression of cancer. In particular, lipid metabolism has been investigated as a source of energy, micro-environmental adaptation, and cell signalling in neoplastic cells. However, the specific role of lipid metabolism dysregulation in hepatocellular carcinoma (HCC) has not been widely described yet. Alterations in fatty acid synthesis, β-oxidation, and cellular lipidic composition contribute to initiation and progression of HCC. The aim of this review is to elucidate the mechanisms by which lipid metabolism is involved in hepatocarcinogenesis and tumour adaptation to different conditions, focusing on the transcriptional aberrations with new insights in lipidomics and lipid zonation. This will help detect new putative therapeutic approaches in the second most frequent cause of cancer-related death.

Expression of SREBP2 and cholesterol metabolism related genes in TCGA glioma cohorts

Diffuse gliomas are the most common primary brain tumors. The Cancer Genome Atlas (TCGA) database provides correlative evidence between altered molecular pathways and gliomas. Dysregulated cholesterol homeostasis emerges as a potential indicator of the pathogenesis of gliomas.Mining large cohorts from the TCGA together with database from the Chinese Glioma Genome Atlas (CGGA) for confirmation, we compared gene expression of cholesterol synthesis master regulator SREBP2 and its regulatory networks in low grade glioma (LGG) and glioblastoma (GBM).Our analysis shows that expression of SREBP2 and related genes is lower in GBM than in LGG, indicating that cholesterol metabolism processes, including de novo synthesis, cholesterol uptakes, and cholesterol conversion and efflux, are suppressed in GBM.Overall, our data suggests that SREBP2 transcript could serve as a potential prognosis marker or therapeutic target in diffuse glioma including GBM.

Hepatocellular carcinoma in the context of non-alcoholic steatohepatitis (NASH): recent advances in the pathogenic mechanisms

Hepatocellular carcinoma (HCC) is the most common type of liver cancer. HCC is particularly aggressive and is one of the leading causes of cancer mortality. In recent decades, the epidemiological landscape of HCC has undergone significant changes. While chronic viral hepatitis and excessive alcohol consumption have long been identified as the main risk factors for HCC, non-alcoholic steatohepatitis (NASH), paralleling the worldwide epidemic of obesity and type 2 diabetes, has become a growing cause of HCC in the US and Europe. Here, we review the recent advances in epidemiological, genetic, epigenetic and pathogenic mechanisms as well as experimental mouse models that have improved the understanding of NASH progression toward HCC. We also discuss the clinical management of patients with NASH-related HCC and possible therapeutic approaches.

Strategy of Hepatic Metabolic Defects Induced by beclin1 Heterozygosity in Adult Zebrafish

Hepatic disorders have been increasing in recent years because of high carbohydrate diets. Hepatocytes depend mainly on the basal autophagy to maintain hepatic glucose/lipid homeostasis in mammals. However, the regulatory mechanisms of autophagy in hepatic energy metabolism are still unknown in fish species. Accordingly, mutant zebrafish lines of autophagy-related genes beclin1 and atg7 were generated by CRISPR/Cas9 gene-editing technology. Interestingly, unlike atg7+/-, male beclin1+/- zebrafish displayed liver defects in the morphology and histology, including abnormal hepatocyte proliferation, hemorrhagic and inflammatory phenotypes. A significant decrease in hepatocyte glycogen and an increase in hepatocyte lipids were detected in the histological assay that coincidence with the hepatic gene expression. Meanwhile, loss of heterozygosity for beclin1 creates a suitable microenvironment for hepatic tumorigenesis via phosphorylation of Akt kinase, which in turn affects liver autophagy. The reduction in autophagy activity in male beclin1+/- liver leads to a disturbance in the glucose/lipid metabolism and negatively regulates apoptosis accompanied by the induction of cellular proliferation and acute inflammatory response. Our findings highlight an important role of beclin1 in zebrafish liver development and energy metabolism, suggesting the crucial role of autophagy in maintaining homeostasis of the nutrient metabolism in fish species.

Role of lipids in pathophysiology, diagnosis and therapy of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is an aggressive and widespread cancer. Patients with liver cirrhosis of different aetiologies are at a risk to develop HCC. It is important to know that in approximately 20% of cases primary liver tumors arise in a non-cirrhotic liver. Lipid metabolism is variable in patients with chronic liver diseases, and lipid metabolites involved therein do play a role in the development of HCC. Of note, lipid composition of carcinogenic tissues differs from non-affected liver tissues. High cholesterol and low ceramide levels in the tumors protect the cells from oxidative stress and apoptosis, and do also promote cell proliferation. So far, detailed characterization of the mechanisms by which lipids enable the development of HCC has received little attention. Evaluation of the complex roles of lipids in HCC is needed to better understand the pathophysiology of HCC, the later being of paramount importance for the development of urgently needed therapeutic interventions. Disturbed hepatic lipid homeostasis has systemic consequences and lipid species may emerge as promising biomarkers for early diagnosis of HCC. The challenge is to distinguish lipids specifically related to HCC from changes simply related to the underlying liver disease. This review article discusses aberrant lipid metabolism in patients with HCC.

SREBP1 as a potential biomarker predicts levothyroxine efficacy of differentiated thyroid cancer

BACKGROUND

SREBP1 is a well-known transcript factor regulating lipogenesis. It has been reported to play an important role in tumor progress in recent years. However, the roles of SREBP1 in differentiated thyroid cancer (DTC) are uncertain. Based on this, we aimed to investigate the expression of SREBP1 and the influence of SREBP1 on DTC patients.

METHODS

qRT-PCR and immunohistochemistry were used to detect the expression of SREBPs in DTC tissues and the adjacent normal tissues. The following methods, including the MTS, colony-forming assay, flow cytometry and Hoechst staining were used to detect the biological function of thyroid cancer cells based on SREBP1 interference or not.

RESULTS

the expression of SREBP1 was significantly different among DTCs, thyroid nodules and the adjacent normal tissues. Briefly, SREBP1 was upregulated follow with the malignancy, but there was no significant difference of SREBP2 between thyroid nodules and the adjacent normal tissues. Further, the ROC curve showed that SREBP1 has higher diagnostic value than SREBP2. SREBP1 expression was significantly related to the tumor size and lymph node metastasis in DTCs. In vitro, the proliferation of thyroid cancer cells was suppressed obviously after interfered with SREBP1, and the apoptotic cells was increased. Further, SREBP1 expression was also associated with the short-term efficacy of levothyroxine in DTC patients.

CONCLUSION

this is the first time to report that SREBP1 is an oncogene and a pro-proliferation factor in thyroid cancer, indicating that SREBP1 may serve as a potential biomarker and therapeutic target in thyroid cancer.

SREBP-1 inhibitor Betulin enhances the antitumor effect of Sorafenib on hepatocellular carcinoma via restricting cellular glycolytic activity

Lipid metabolism that correlates tightly to the glucose metabolic regulation in malignant cells includes hepatocellular carcinoma (HCC) cells. The transcription factor Sterol Regulatory Element Binding Protein 1 (SREBP-1), a regulator of fatty acid synthesis, has been shown to pivotally regulate the proliferation and metastasis of HCC cells. However, the intrinsic mechanism by which SREBP-1 regulates the survival of HCC cells remains unclear. In this study, among HCC patients who had dismal responses to Sorafenib, a high SREBP-1 level was found in the tumors and correlated to poor survival. This observation suggested the negative role of SREBP-1 in clinical HCC prognosis. Our mechanistical studies reveal that the inhibition of SREBP-1 via its inhibitor Betulin suppresses cellular glucose metabolism. In addition to the reduced glycolytic activity, a thwarted metastatic potential was observed in HCC cells upon Betulin administration. Moreover, our data show that SREBP-1 inhibition facilitated the antitumor effects of Sorafenib on HCC cells and xenograft tumors.

Demethylation of SOCS1 mediates its abnormally high expression in ovarian cancer

The present study aimed to investigate the association between methylation and the high expression of the suppressor of cytokine signaling 1 (SOCS1) in ovarian cancer by detecting the methylation rate and the degree of expression. The present study investigated the expression of SOCS1 mRNA and SOCS1 protein in ovarian cancer and normal ovary tissues using reverse transcription-quantitative polymerase chain reaction (PCR) and immunohistochemistry, and the methylation status of the CpG islands of SOCS1 mRNA in ovarian cancer tissue were examined using a methylation-specific PCR. The expression levels of SOCS1 mRNA in ovarian cancer specimens were significantly increased compared with that in the normal ovary tissues (P=0.0215). Consistent with this, the expression levels of SOCS1 protein in ovarian cancer specimens were significantly increased, while the methylation rate of SOCS1 mRNA was significantly decreased compared with that in the normal ovary tissues. Therefore, it may be concluded that the low methylation rate of SOCS1 mRNA in ovarian cancer increased the expression of SOCS1 mRNA, which may serve a role in the development of ovarian cancer.

mTOR direct crosstalk with STAT5 promotes de novo lipid synthesis and induces hepatocellular carcinoma

Hepatocellular carcinoma (HCC) can be the last step of nonalcoholic fatty liver disease (NAFLD) evolution, and the main characteristic of NAFLD is alteration in lipid metabolism. However, the mechanisms of abnormal lipid metabolism in NAFLD and HCC progression are yet to be identified. Here, we demonstrate that liver-specific activation of mTORC1 promoted the expression of lipid synthesis genes and lead to the development of spontaneous HCC. Genetic mouse models developed spontaneous HCC along with increased expressions of SREBP1, ACC1 and FASN. In addition, high levels of p-STAT5 were observed in the livers and particularly evident in the tumor area. And the synthesis of p-STAT5 was increased in patients along with the increase in SREBP1 synthesis in clinical samples. Moreover, mTORC1 interacts with and phosphorylates the STAT5 in hepatocytes. In conclusion, our data suggested that mTORC1 upregulates SREBP1 transcription via crosstalk with the STAT5 pathway which contributes to the NAFLD-related HCC pathogenesis. And the inhibitor of SREBP1 and mTOR may help to prevent HCC in clinical NAFLD patients.