Fatty-acid-induced FABP5/HIF-1 reprograms lipid metabolism and enhances the proliferation of liver cancer cells

TEAD4 Activates PCSK9 to Promote Stomach Adenocarcinoma Cell Stemness through Fatty Acid Metabolism

INTRODUCTION

This study attempted to investigate how proprotein convertase subtilisin/kexin type 9 (PCSK9) influences the stemness of stomach adenocarcinoma (STAD) cells.

METHODS

CCK-8 and sphere-formation assays were used to detect cell viability and stemness. qRT-PCR and Western blot were used to detect PCSK9 and TEAD4 expression. The binding relationship was verified by dual-luciferase and chromatin immunoprecipitation assays. The effect of TEAD4 activating PCSK9 on the stemness of STAD cells was detected by bioinformatics, BODIPY 493/503, Oil red O, Western blot, and kits. In vivo experiments verified the role of the TEAD4/PCSK9 axis in tumor formation in nude mice.

RESULTS

PCSK9 and TEAD4 were highly expressed in STAD. PCSK9 was enriched in the fatty acid metabolism (FAM) pathway. PCSK9 activated the fatty acid metabolism and promoted the proliferation and stemness of STAD cells. TEAD4 as a transcription factor upstream of PCSK9, cell experiments revealed that knockdown of PCSK9 inhibited STAD cell stemness, whereas further addition of fatty acid inhibitors could attenuate the promoting effect on STAD cell stemness brought by STAD overexpression. Rescue experiments showed overexpressed PCSK9 exerted an inhibitory effect on the stemness of STAD cells brought by TEAD4 knockdown. The hypothesis that TEAD4/PCSK9 axis can promote STAD cell growth was confirmed by in vivo experiments.

CONCLUSION

Transcription factor TEAD4 could activate PCSK9 to promote the stemness of STAD cells through FAM. These results added weight to the assumption that TEAD4/PCSK9 axis has the potential to be the therapeutic target that inhibits cancer stem cell in STAD.

Fatty acid-binding protein 5 is a functional biomarker and indicator of ferroptosis in cerebral hypoxia

The progression of human degenerative and hypoxic/ischemic diseases is accompanied by widespread cell death. One death process linking iron-catalyzed reactive species with lipid peroxidation is ferroptosis, which shows hallmarks of both programmed and necrotic death in vitro. While evidence of ferroptosis in neurodegenerative disease is indicated by iron accumulation and involvement of lipids, a stable marker for ferroptosis has not been identified. Its prevalence is thus undetermined in human pathophysiology, impeding recognition of disease areas and clinical investigations with candidate drugs. Here, we identified ferroptosis marker antigens by analyzing surface protein dynamics and discovered a single protein, Fatty Acid-Binding Protein 5 (FABP5), which was stabilized at the cell surface and specifically elevated in ferroptotic cell death. Ectopic expression and lipidomics assays demonstrated that FABP5 drives redistribution of redox-sensitive lipids and ferroptosis sensitivity in a positive-feedback loop, indicating a role as a functional biomarker. Notably, immunodetection of FABP5 in mouse stroke penumbra and in hypoxic postmortem patients was distinctly associated with hypoxically damaged neurons. Retrospective cell death characterized here by the novel ferroptosis biomarker FABP5 thus provides first evidence for a long-hypothesized intrinsic ferroptosis in hypoxia and inaugurates a means for pathological detection of ferroptosis in tissue.

Proteomic analysis of DEN and CCl4-induced hepatocellular carcinoma mouse model

Hepatocellular carcinoma (HCC) seriously threatens human health, mostly developed from liver fibrosis or cirrhosis. Since diethylnitrosamine (DEN) and carbon tetrachloride (CCl4)-induced HCC mouse model almost recapitulates the characteristic of HCC with fibrosis and inflammation, it is taken as an essential tool to investigate the pathogenesis of HCC. However, a comprehensive understanding of the protein expression profile of this model is little. In this study, we performed proteomic analysis of this model to elucidate its proteomic characteristics. Compared with normal liver tissues, 432 differentially expressed proteins (DEPs) were identified in tumor tissues, among which 365 were up-regulated and 67 were down-regulated. Through Gene Ontology (GO) analysis, Ingenuity Pathway Analysis (IPA), protein-protein interaction networks (PPI) analysis and Gene-set enrichment analysis (GSEA) analysis of DEPs, we identified two distinguishing features of DEN and CCl4-induced HCC mouse model in protein expression, the upregulation of actin cytoskeleton and branched-chain amino acids metabolic reprogramming. In addition, matching DEPs from the mouse model to homologous proteins in the human HCC cohort revealed that the DEN and CCl4-induced HCC mouse model was relatively similar to the subtype of HCC with poor prognosis. Finally, combining clinical information from the HCC cohort, we screened seven proteins with prognostic significance, SMAD2, PTPN1, PCNA, MTHFD1L, MBOAT7, FABP5, and AGRN. Overall, we provided proteomic data of the DEN and CCl4-induced HCC mouse model and highlighted the important proteins and pathways in it, contributing to the rational application of this model in HCC research.

Hypoxia expedites the progression of papillary thyroid carcinoma by promoting the CPT1A-mediated fatty acid oxidative pathway

Hypoxia has been reported to promote the proliferation and migration of thyroid cancer, while the special mechanism was still unclear. HIF-1α/carnitine palmitoyl-transferase 1A (CPT1A) was found to be associated with papillary thyroid carcinoma (PTC) but the biological role of CPT1A in PTC was not explored. The effects of hypoxia and carnitine palmitoyl-transferase 1A (CPT1A) expression on PTC cells were determined by cell counting kit-8 assay, detection of oxidative stress, inflammation response and mitochondrial membrane motential (MMP). Oil Red O staining and the detection of free fatty acids were performed to assess the status of lipid metabolism. Flow cytometric analysis was performed to assess cell apoptosis. Quantitative polymerase chain reaction (qPCR) and western blot analysis were applied to investigate the expressions of CPT1A and HIF-1α and the molecules involved cell function. The expressions of CPT1A and HIF-1α were significantly increased in PTC cells with or without hypoxia treatment. CPT1A overexpression or silencing promoted or inhibited cell viability, and hypoxia further repressed cell viability. In addition, CPT1A overexpression alleviates hypoxia-induced increased oxidative stress, inflammation response and elevated MMP. CPT1A overexpression enhanced palmitic acid-induced decreased cell growth, enhanced the metabolic capacity of free fatty acid and suppressed cell apoptosis. Animal experiments showed that CPT1A overexpression promoted PTC tumor growth, reduced lipid deposition, oxidative stress and inflammation, as well as enhancing cell function indicators. However, CPT1A silencing showed the opposite effects both in vitro and in vivo. Hypoxia induces the high expression of HIF-1α/CPT1A, thereby reprogramming the lipid metabolism of PTC cells for adapting the hypoxia environment, meanwhile inhibiting the cell damage and apoptosis caused by oxidative stress.

Fatty acid binding protein 5 suppression attenuates obesity-induced hepatocellular carcinoma by promoting ferroptosis and intratumoral immune rewiring

Due to the rise in overnutrition, the incidence of obesity-induced hepatocellular carcinoma (HCC) will continue to escalate; however, our understanding of the obesity to HCC developmental axis is limited. We constructed a single-cell atlas to interrogate the dynamic transcriptomic changes during hepatocarcinogenesis in mice. Here we identify fatty acid binding protein 5 (FABP5) as a driver of obesity-induced HCC. Analysis of transformed cells reveals that FABP5 inhibition and silencing predispose cancer cells to lipid peroxidation and ferroptosis-induced cell death. Pharmacological inhibition and genetic ablation of FABP5 ameliorates the HCC burden in male mice, corresponding to enhanced ferroptosis in the tumour. Moreover, FABP5 inhibition induces a pro-inflammatory tumour microenvironment characterized by tumour-associated macrophages with increased expression of the co-stimulatory molecules CD80 and CD86 and increased CD8+ T cell activation. Our work unravels the dual functional role of FABP5 in diet-induced HCC, inducing the transformation of hepatocytes and an immunosuppressive phenotype of tumour-associated macrophages and illustrates FABP5 inhibition as a potential therapeutic approach.

Importance of fatty acid binding proteins in cellular function and organismal metabolism

Fatty acid binding proteins (Fabps) are small soluble proteins that are abundant in the cytosol. These proteins are known to bind a myriad of small hydrophobic molecules and have been postulated to serve a variety of roles, yet their precise functions have remained an enigma over half a century of study. Here, we consider recent findings, along with the cumulative findings contributed by many laboratories working on Fabps over the last half century, to synthesize a new outlook for what functions Fabps serve in cells and organisms. Collectively, the findings illustrate that Fabps function as versatile multi-purpose devices serving as sensors, conveyors and modulators to enable cells to detect and handle a specific class of metabolites, and to adjust their metabolic capacity and efficiency.

Basal MET phosphorylation is an indicator of hepatocyte dysregulation in liver disease

Chronic liver diseases are worldwide on the rise. Due to the rapidly increasing incidence, in particular in Western countries, metabolic dysfunction-associated steatotic liver disease (MASLD) is gaining importance as the disease can develop into hepatocellular carcinoma. Lipid accumulation in hepatocytes has been identified as the characteristic structural change in MASLD development, but molecular mechanisms responsible for disease progression remained unresolved. Here, we uncover in primary hepatocytes from a preclinical model fed with a Western diet (WD) an increased basal MET phosphorylation and a strong downregulation of the PI3K-AKT pathway. Dynamic pathway modeling of hepatocyte growth factor (HGF) signal transduction combined with global proteomics identifies that an elevated basal MET phosphorylation rate is the main driver of altered signaling leading to increased proliferation of WD-hepatocytes. Model-adaptation to patient-derived hepatocytes reveal patient-specific variability in basal MET phosphorylation, which correlates with patient outcome after liver surgery. Thus, dysregulated basal MET phosphorylation could be an indicator for the health status of the liver and thereby inform on the risk of a patient to suffer from liver failure after surgery.

High levels of fatty acid-binding protein 5 excessively enhances fatty acid synthesis and proliferation of granulosa cells in polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is one of the most complex endocrine disorders in women of reproductive age. Abnormal proliferation of granulosa cells (GCs) is an important cause of PCOS. This study aimed to explore the role of fatty acid-binding protein 5 (FABP5) in granulosa cell (GC) proliferation in polycystic ovary syndrome (PCOS) patients.

METHODS

The FABP5 gene, which is related to lipid metabolism, was identified through data analysis of the gene expression profiles of GSE138518 from the Gene Expression Omnibus (GEO) database. The expression levels of FABP5 were measured by quantitative real-time PCR (qRT‒PCR) and western blotting. Cell proliferation was evaluated with a cell counting kit-8 (CCK-8) assay. Western blotting was used to assess the expression of the proliferation marker PCNA, and immunofluorescence microscopy was used to detect Ki67 expression. Moreover, lipid droplet formation was detected with Nile red staining, and qRT‒PCR was used to analyze fatty acid storage-related gene expression.

RESULTS

We found that FABP5 was upregulated in ovarian GCs obtained from PCOS patients and PCOS mice. FABP5 knockdown suppressed lipid droplet formation and proliferation in a human granulosa-like tumor cell line (KGN), whereas FABP5 overexpression significantly enhanced lipid droplet formation and KGN cell proliferation. Moreover, we determined that FABP5 knockdown inhibited PI3K-AKT signaling by suppressing AKT phosphorylation and that FABP5 overexpression activated PI3K-AKT signaling by facilitating AKT phosphorylation. Finally, we used the PI3K-AKT signaling pathway inhibitor LY294002 and found that the facilitation of KGN cell proliferation and lipid droplet formation induced by FABP5 overexpression was inhibited. In contrast, the PI3K-AKT signaling pathway agonist SC79 significantly rescued the suppression of KGN cell proliferation and lipid droplet formation caused by FABP5 knockdown.

CONCLUSIONS

FABP5 promotes active fatty acid synthesis and excessive proliferation of GCs by activating PI3K-AKT signaling, suggesting that abnormally high expression of FABP5 in GCs may be a novel biomarker or a research target for PCOS treatment.

A novel risk score system based on immune subtypes for identifying optimal mRNA vaccination population in hepatocellular carcinoma

PURPOSE

Although mRNA vaccines have shown certain clinical benefits in multiple malignancies, their therapeutic efficacies against hepatocellular carcinoma (HCC) remains uncertain. This study focused on establishing a novel risk score system based on immune subtypes so as to identify optimal HCC mRNA vaccination population.

METHODS

GEPIA, cBioPortal and TIMER databases were utilized to identify candidate genes for mRNA vaccination in HCC. Subsequently, immune subtypes were constructed based on the candidate genes. According to the differential expressed genes among various immune subtypes, a risk score system was established using machine learning algorithm. Besides, multi-color immunofluorescence of tumor tissues from 72 HCC patients were applied to validate the feasibility and efficiency of the risk score system.

RESULTS

Twelve overexpressed and mutated genes associated with poor survival and APCs infiltration were identified as potential candidate targets for mRNA vaccination. Three immune subtypes (e.g. IS1, IS2 and IS3) with distinct clinicopathological and molecular profiles were constructed according to the 12 candidate genes. Based on the immune subtype, a risk score system was developed, and according to the risk score from low to high, HCC patients were classified into four subgroups on average (e.g. RS1, RS2, RS3 and RS4). RS4 mainly overlapped with IS3, RS1 with IS2, and RS2+RS3 with IS1. ROC analysis also suggested the significant capacity of the risk score to distinguish between the three immune subtypes. Higher risk score exhibited robustly predictive ability for worse survival, which was further independently proved by multi-color immunofluorescence of HCC samples. Notably, RS4 tumors exhibited an increased immunosuppressive phenotype, higher expression of the twelve potential candidate targets and increased genome altered fraction, and therefore might benefit more from vaccination.

CONCLUSIONS

This novel risk score system based on immune subtypes enabled the identification of RS4 tumor that, due to its highly immunosuppressive microenvironment, may benefit from HCC mRNA vaccination.

Effect of Semaglutide on High-Fat-Diet-Induced Liver Cancer in Obese Mice

This study aims to investigate the impact of semaglutide on the expression of liver cancer proteins in obese mice induced by a high-fat diet. Sixteen obese mice were randomly divided into two groups: the high-fat diet group and the semaglutide group, each consisting of eight mice. Additionally, eight normal male mice were included as the control group. Serum samples were collected, and a differential expression analysis of total proteins in adipose tissue was performed using quantitative tandem mass spectrometry (TMT) in combination with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Significant differential proteins were identified and subjected to a bioinformatics analysis. The findings revealed that these differential proteins, namely, integrin αV (ITGAV), laminin γ1 (LAMC1), fatty acid-binding protein 5 (FABP5), and lipoprotein lipase (LPL), regulate the occurrence and development of liver cancer by participating in the extracellular matrix (ECM) signaling pathway and the peroxisome proliferator-activated receptor (PPAR) signaling pathway. Notably, semaglutide can decelerate the progression of liver cancer by inducing the expression of ITGAV, LAMC1, FABP5, and LPL in the adipose tissue of obese mice.

Sulfotransferase SULT2B1 facilitates colon cancer metastasis by promoting SCD1-mediated lipid metabolism

Metastasis is responsible for at least 90% of colon cancer (CC)-related deaths. Lipid metabolism is a critical factor in cancer metastasis, yet the underlying mechanism requires further investigation. Herein, through the utilisation of single-cell sequencing and proteomics, we identified sulfotransferase SULT2B1 as a novel metastatic tumour marker of CC, which was associated with poor prognosis. CC orthotopic model and in vitro assays showed that SULT2B1 promoted lipid metabolism and metastasis. Moreover, SULT2B1 directly interacted with SCD1 to facilitate lipid metabolism and promoted metastasis of CC cells. And the combined application of SCD1 inhibitor CAY with SULT2B1- konockout (KO) demonstrated a more robust inhibitory effect on lipid metabolism and metastasis of CC cells in comparison to sole application of SULT2B1-KO. Notably, we revealed that lovastatin can block the SULT2B1-induced promotion of lipid metabolism and distant metastasis in vivo. Further evidence showed that SMC1A transcriptionally upregulated the expression of SULT2B1. Our findings unveiled the critical role of SULT2B1 in CC metastasis and provided a new perspective for the treatment of CC patients with distant metastasis.

HIF-1A as a prognostic biomarker related to invasion, migration and immunosuppression of cervical cancer

Background

The incidence of cervical cancer ranks second among malignant tumors in women, exerting a significant impact on their quality of life and overall well-being. The hypoxic microenvironment plays a pivotal role in the initiation and progression of tumorigenesis. The present study aims to investigate the fundamental genes and pathways associated with the hypoxia-inducible factor (HIF-1A) in cervical cancer, aiming to identify potential downstream targets for diagnostic and therapeutic purposes.

Methods

We obtained dataset GSE63514 from the Comprehensive Gene Expression Database (GEO). The dataset comprised of 24 patients in the normal group and 28 patients in the tumor group. Gene set difference analysis (GSVA) and gene set enrichment analysis (GSEA) were used to identify the genes related to HIF-1A expression and the specific signaling pathways involved.The association between HIF-1A and tumor immune infiltration was examined in the TCGA dataset. The WGCAN network was constructed to identify key genes within the blue module, and subsequent gene ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were conducted to determine the pathways and functional annotations associated with HIF-1A. The protein interaction network of the HIF-1A gene was obtained from the STRING database and visualized using Cytoscape in the meantime.The function of HIF-1A and its related gene expression were verified in vivo.

Results

HIF-1A was a risk factor in both univariate and multivariate Cox regression analysis of cervical cancer patients. A total of 344 genes significantly correlated with the expression of HIF-1A were identified through correlation analysis, and the genes exhibiting the strongest correlation were obtained. The major signaling pathways involved in HIF-1A encompass TNF-α/NF-κB, PI3K/AKT/MTOR, TGF-β, JAK-STAT, and various other signaling cascades. Reinforced by qRT-PCR, we identified Integrin beta-1 (ITGB1), C-C motif chemokine ligand 2 (CCL2), striatin 3 (STRN3), and endothelin-1 (EDN1) as pivotal downstream genes influenced by HIF-1A. HIF-1A is associated with immune infiltration of natural killer (NK) cells, mast cells, CD4+T cells, M0 macrophages, neutrophils, follicular helper T cells, CD8+T cells, and regulatory T cells (Treg). HIF-1A is associated with sensitivity to chemotherapy drugs. The identification of the HIF-1A pathway and its function primarily focuses on cytoplasmic translation, aerobic respiration, cellular respiration, oxidative phosphorylation, thermogenesis, among others. The results of in vivo experiments have confirmed that HIF-1A plays a crucial role in promoting the migration and invasion of cervical cancer cells. Moreover, the overexpression of HIF-1A led to an upregulation in the expressions of ITGB1, CCL2, STRN3, and EDN1.

Conclusions

The role of HIF-1A in cervical cancer was determined through a combination of bioinformatics analysis and experimental validation. The genes potentially implicated in the tumorigenesis mechanism of HIF-1A were identified. These findings has the potential to enhance our comprehension of the progression of cervical cancer and offer promising therapeutic targets for its clinical management.

Cancer metabolism and carcinogenesis

Metabolic reprogramming is an emerging hallmark of cancer cells, enabling them to meet increased nutrient and energy demands while withstanding the challenging microenvironment. Cancer cells can switch their metabolic pathways, allowing them to adapt to different microenvironments and therapeutic interventions. This refers to metabolic heterogeneity, in which different cell populations use different metabolic pathways to sustain their survival and proliferation and impact their response to conventional cancer therapies. Thus, targeting cancer metabolic heterogeneity represents an innovative therapeutic avenue with the potential to overcome treatment resistance and improve therapeutic outcomes. This review discusses the metabolic patterns of different cancer cell populations and developmental stages, summarizes the molecular mechanisms involved in the intricate interactions within cancer metabolism, and highlights the clinical potential of targeting metabolic vulnerabilities as a promising therapeutic regimen. We aim to unravel the complex of metabolic characteristics and develop personalized treatment approaches to address distinct metabolic traits, ultimately enhancing patient outcomes.

FABP6 serves as a new therapeutic target in esophageal tumor

BACKGROUND

Esophageal cancer is one of the most common malignant tumors with high incidence and mortality rates. Despite the continuous development of treatment options, the prognosis for esophageal cancer patients remains poor. Therefore, there is an urgent need for new diagnostic and therapeutic targets in clinical practice to improve the survival of patients with esophageal cancer.

METHODS

In this study, we conducted a comprehensive scRNA-seq analysis of the tumor microenvironment in primary esophageal tumors to elucidate cell composition and heterogeneity. Using Seurat, we identified eight clusters, encompassing non-immune cells (fibroblasts, myofibroblasts, endothelial cells, and epithelial cells) and immunocytes (myeloid-derived cells, T cells, B cells, and plasma cells). Compared to normal tissues, tumors exhibited an increased proportion of epithelial cells and alterations in immune cell infiltration. Analysis of epithelial cells revealed a cluster (cluster 0) with a high differentiation score and early distribution, suggesting its importance as a precursor cell.

RESULTS

Cluster 0 was characterized by high expression of FABP6, indicating a potential role in fatty acid metabolism and tumor growth. T cell analysis revealed shifts in the balance between Treg and CD8+ effector T cells in tumor tissues. Cellular communication analysis identified increased interactions between FABP6+ tumor cells and T cells, with the involvement of the MIF-related pathway and the CD74-CD44 interaction. This study provides insights into the cellular landscape and immune interactions within esophageal tumors, contributing to a better understanding of tumor heterogeneity and potential therapeutic targets.

Hypoxia induces mitochondrial protein lactylation to limit oxidative phosphorylation

Oxidative phosphorylation (OXPHOS) consumes oxygen to produce ATP. However, the mechanism that balances OXPHOS activity and intracellular oxygen availability remains elusive. Here, we report that mitochondrial protein lactylation is induced by intracellular hypoxia to constrain OXPHOS. We show that mitochondrial alanyl-tRNA synthetase (AARS2) is a protein lysine lactyltransferase, whose proteasomal degradation is enhanced by proline 377 hydroxylation catalyzed by the oxygen-sensing hydroxylase PHD2. Hypoxia induces AARS2 accumulation to lactylate PDHA1 lysine 336 in the pyruvate dehydrogenase complex and carnitine palmitoyltransferase 2 (CPT2) lysine 457/8, inactivating both enzymes and inhibiting OXPHOS by limiting acetyl-CoA influx from pyruvate and fatty acid oxidation, respectively. PDHA1 and CPT2 lactylation can be reversed by SIRT3 to activate OXPHOS. In mouse muscle cells, lactylation is induced by lactate oxidation-induced intracellular hypoxia during exercise to constrain high-intensity endurance running exhaustion time, which can be increased or decreased by decreasing or increasing lactylation levels, respectively. Our results reveal that mitochondrial protein lactylation integrates intracellular hypoxia and lactate signals to regulate OXPHOS.

Identification of metabolism terms significantly affecting hepatocellular carcinoma immune microenvironment and immunotherapy response

Metabolic pathways exert a significant influence on the onset and progression of cancer. Public data on hepatocellular carcinoma (HCC) patients were obtained from The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) databases. Analysis was performed in R software using different R packages. Here, we integrated the data from multiple independent HCC cohorts, including TCGA-LIHC, ICGC-FR and ICGC-JP. Then, the enrichment score of 21 metabolism-related pathways was quantified using the ssGSEA algorithm. Next, univariate Cox regression analysis was applied to identify the metabolic terms with significant correlation to patient survival. Finally, a prognosis model based on linoleic acid metabolism, sphingolipid metabolism and regulation of lipolysis in adipocytes was established, which showed good performance in predicting patients' survival. Furthermore, we conducted a biological enrichment analysis to delineate the biological disparities between high- and low-risk patients. Notably, we discerned differences in the microenvironments between these two patient groups. We also found that low-risk patients could potentially respond better to immunotherapy. Drug sensitivity analysis suggested that low-risk patients are more susceptible to bexarotene and erlotinib, yet exhibit resistance to ATRA and bleomycin. Furthermore, through the use of LASSO logistic regression analysis, we identified 19 characteristic genes, which could robustly indicate the risk groups. Our research underscores the role of linoleic acid metabolism, sphingolipid metabolism and the regulation of lipolysis in adipocytes in HCC, pointing towards potential avenues for future research.

Multiomic analysis of cervical squamous cell carcinoma identifies cellular ecosystems with biological and clinical relevance

Cervical squamous cell carcinoma (CSCC) exhibits a limited response to immune-checkpoint blockade. Here we conducted a multiomic analysis encompassing single-cell RNA sequencing, spatial transcriptomics and spatial proteomics, combined with genetic and pharmacological perturbations to systematically develop a high-resolution and spatially resolved map of intratumoral expression heterogeneity in CSCC. Three tumor states (epithelial-cytokeratin, epithelial-immune (Epi-Imm) and epithelial senescence), recapitulating different stages of squamous differentiation, showed distinct tumor immune microenvironments. Bidirectional interactions between epithelial-cytokeratin malignant cells and immunosuppressive cancer-associated fibroblasts form an immune exclusionary microenvironment through transforming growth factor β pathway signaling mediated by FABP5. In Epi-Imm tumors, malignant cells interact with natural killer and T cells through interferon signaling. Preliminary analysis of samples from a cervical cancer clinical trial ( NCT04516616 ) demonstrated neoadjuvant chemotherapy induces a state transition to Epi-Imm, which correlates with pathological complete remission following treatment with immune-checkpoint blockade. These findings deepen the understanding of cellular state diversity in CSCC.

Impeding DNA Polymerase β Activity by Oleic Acid to Inhibit Base Excision Repair and Induce Mitochondrial Dysfunction in Hepatic Cells

Free fatty acids (FFAs) hepatic accumulation and the resulting oxidative stress contribute to several chronic liver diseases including nonalcoholic steatohepatitis. However, the underlying pathological mechanisms remain unclear. In this study, we propose a novel mechanism whereby the toxicity of FFAs detrimentally affects DNA repair activity. Specifically, we have discovered that oleic acid (OA), a prominent dietary free fatty acid, inhibits the activity of DNA polymerase β (Pol β), a crucial enzyme involved in base excision repair (BER), by actively competing with 2'-deoxycytidine-5'-triphosphate. Consequently, OA hinders the efficiency of BER, leading to the accumulation of DNA damage in hepatocytes overloaded with FFAs. Additionally, the excessive presence of both OA and palmitic acid (PA) lead to mitochondrial dysfunction in hepatocytes. These findings suggest that the accumulation of FFAs hampers Pol β activity and contributes to mitochondrial dysfunction, shedding light on potential pathogenic mechanisms underlying FFAs-related diseases.

The role of noncoding RNAs in the tumor microenvironment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the leading fatal malignancy worldwide. The tumor microenvironment (TME) can affect the survival, proliferation, migration, and even dormancy of cancer cells. Hypoxia is an important component of the TME, and hypoxia-inducible factor-1α (HIF-1α) is the most important transcriptional regulator. Noncoding RNAs (ncRNAs), including microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs), comprise a large part of the human transcriptome and play an important role in regulating the tumorigenesis of HCC. This review discusses the role of ncRNAs in hepatocarcinogenesis, epithelial-mesenchymal transition (EMT), and angiogenesis in a hypoxic microenvironment, as well as the interactions between ncRNAs and key components of the TME. It further discusses their use as biomarkers and the potential clinical value of drugs, as well as the challenges faced in the future.

Sensing the oxygen and temperature in the adipose tissues - who's sensing what?

Adipose tissues, composed of various cell types, including adipocytes, endothelial cells, neurons, and immune cells, are organs that are exposed to dynamic environmental challenges. During diet-induced obesity, white adipose tissues experience hypoxia due to adipocyte hypertrophy and dysfunctional vasculature. Under these conditions, cells in white adipose tissues activate hypoxia-inducible factor (HIF), a transcription factor that activates signaling pathways involved in metabolism, angiogenesis, and survival/apoptosis to adapt to such an environment. Exposure to cold or activation of the β-adrenergic receptor (through catecholamines or chemicals) leads to heat generation, mainly in brown adipose tissues through activating uncoupling protein 1 (UCP1), a proton uncoupler in the inner membrane of the mitochondria. White adipose tissues can undergo a similar process under this condition, a phenomenon known as 'browning' of white adipose tissues or 'beige adipocytes'. While UCP1 expression has largely been confined to adipocytes, HIF can be expressed in many types of cells. To dissect the role of HIF in specific types of cells during diet-induced obesity, researchers have generated tissue-specific knockout (KO) mice targeting HIF pathways, and many studies have commonly revealed that intact HIF-1 signaling in adipocytes and adipose tissue macrophages exacerbates tissue inflammation and insulin resistance. In this review, we highlight some of the key findings obtained from these transgenic mice, including Ucp1 KO mice and other models targeting the HIF pathway in adipocytes, macrophages, or endothelial cells, to decipher their roles in diet-induced obesity.

HIF‑1α and RACGAP1 promote the progression of hepatocellular carcinoma in a mutually regulatory way

Hypoxia, a condition characterized by low oxygen levels, serves an important role in the progression of hepatocellular carcinoma (HCC). However, the precise molecular mechanisms underlying hypoxia‑induced HCC progression are yet to be fully elucidated. The present study assessed the involvement of two key factors, hypoxia‑inducible factor‑1α (HIF‑1α) and Rac GTPase activating protein 1 (RACGAP1), in HCC development under hypoxic conditions. HIF‑1α and RACGAP1 genes were overexpressed and knocked down in Hep3B and Huh7 cells using lentiviral transduction and the levels of HIF‑1α and RACGAP1 in the cells were assessed using quantitative PCR, western blotting and immunofluorescence. Co‑immunoprecipitation experiments were performed to evaluate the interaction between HIF‑1α and RACGAP1. Subsequently, the proliferation, apoptosis, migration and invasion of Hep3B and Huh7 cells were assessed using the Cell Counting Kit‑8 assay, flow cytometry, Transwell assay and migration experiments. The expression levels of HIF‑1α and RACGAP1 in normal and HCC tumor samples were analyzed utilizing the Gene Expression Profiling Interactive Analysis database. Furthermore, correlations between HIF‑1α/RACGAP1 gene expression levels and patient survival outcomes were evaluated using the Kaplan‑Meier plotter. Knockdown of HIF‑1α resulted in a significant decrease in RACGAP1 expression, whilst overexpression of HIF‑1α resulted in a significant increase in RACGAP1 expression. Moreover, overexpression and knockdown of RACGAP1 had the same effect on HIF‑1α expression. Additionally, it was demonstrated that HIF‑1α and RACGAP1 interacted directly within a complex. Overexpression of HIF‑1α or RACGAP1 significantly increased proliferation, invasion and migration, and significantly decreased the proportion of apoptotic Hep3B and Huh7 cells. Conversely, knockdown of HIF‑1α or RACGAP1 significantly decreased proliferation, invasion and migration, and significantly increased the proportion of apoptotic Hep3B and Huh7 cells. In addition, the combined knockdown or overexpression of HIF‑1α and RACGAP1 had a more pronounced effect on HCC cell migration compared with knockdown of HIF‑1α alone. Furthermore, there was a significant positive correlation between the expression levels of HIF‑1α and RACGAP1 in HCC tissues and patients with HCC and upregulation of both HIF‑1α and RACGAP1 demonstrated a lower overall survival probability. In conclusion, HIF‑1α and RACGAP1 may synergistically contribute to the development of HCC, highlighting their potential as valuable targets for HCC therapy.

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.

Lipid metabolic reprogramming in tumor microenvironment: from mechanisms to therapeutics

Lipid metabolic reprogramming is an emerging hallmark of cancer. In order to sustain uncontrolled proliferation and survive in unfavorable environments that lack oxygen and nutrients, tumor cells undergo metabolic transformations to exploit various ways of acquiring lipid and increasing lipid oxidation. In addition, stromal cells and immune cells in the tumor microenvironment also undergo lipid metabolic reprogramming, which further affects tumor functional phenotypes and immune responses. Given that lipid metabolism plays a critical role in supporting cancer progression and remodeling the tumor microenvironment, targeting the lipid metabolism pathway could provide a novel approach to cancer treatment. This review seeks to: (1) clarify the overall landscape and mechanisms of lipid metabolic reprogramming in cancer, (2) summarize the lipid metabolic landscapes within stromal cells and immune cells in the tumor microenvironment, and clarify their roles in tumor progression, and (3) summarize potential therapeutic targets for lipid metabolism, and highlight the potential for combining such approaches with other anti-tumor therapies to provide new therapeutic opportunities for cancer patients.

Lipids, cholesterols, statins and liver cancer: a Mendelian randomization study

Aim

To investigate the causal relationship of serum lipid indicators and lipid-lowering drugs with the risk of liver cancer using Mendelian randomization study.

Methods

A two-sample Mendelian randomization (TSMR) study was performed to investigate the causal relationship between serum levels of lipid indicators and liver cancer, including low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), triglycerides (TG), total cholesterol (TC), Apolipoprotein B (ApoB), and Apolipoprotein A1 (ApoA1).Furthermore, instrumental variable weighted regression (IVW) and summary data-based MR (SMR) analyses were performed to investigate the causal effects of lipid-lowering drugs, including statins and PCSK9 inhibitors, on the risk of liver cancer.

Results

Serum LDL-c and serum TC levels showed negatively associated with liver cancer (n = 22 SNPs, OR = 0.363, 95% CI = 0.231 - 0.570; p = 1.070E-5) (n = 83 SNPs; OR = 0.627, 95% CI = 0.413-0.952; p = 0.028). However, serum levels of TG, HDL-c, and ApoA1 did not show any significant correlation with liver cancer. In the drug target MR (DMR) analyses, HMGCR-mediated level of LDL-c showed an inverse relationship with the risk of liver cancer in the IVW-MR analysis (n = 5 SNPs, OR = 0.201, 95% CI = 0.064 - 0.631; p = 5.95E-03) and SMR analysis (n = 20 SNPs, OR = 0.245, 95% CI = 0.065 - 0.926; p = 0.038) However, PCSK9 did not show any significant association with liver cancer based on both the IVW-MR and SMR analyses.

Conclusion

Our results demonstrated that reduced levels of LDL-c and TC were associated with an increased risk of liver cancer. Furthermore, lipid-lowering drugs targeting HMGCR such as statins were associated with increased risk of liver cancer.

Hepatocellular carcinoma: molecular mechanism, targeted therapy, and biomarkers

Hepatocellular carcinoma (HCC) is a common malignancy and one of the leading causes of cancer-related death. The biological process of HCC is complex, with multiple factors leading to the broken of the balance of inactivation and activation of tumor suppressor genes and oncogenes, the abnormal activation of molecular signaling pathways, the differentiation of HCC cells, and the regulation of angiogenesis. Due to the insidious onset of HCC, at the time of first diagnosis, less than 30% of HCC patients are candidates for radical treatment. Systematic antitumor therapy is the hope for the treatment of patients with middle-advanced HCC. Despite the emergence of new systemic therapies, survival rates for advanced HCC patients remain low. The complex pathogenesis of HCC has inspired researchers to explore a variety of biomolecular targeted therapeutics targeting specific targets. Correct understanding of the molecular mechanism of HCC occurrence is key to seeking effective targeted therapy. Research on biomarkers for HCC treatment is also advancing. Here, we explore the molecular mechanism that are associated with HCC development, summarize targeted therapies for HCC, and discuss potential biomarkers that may drive therapies.

Prognosis analysis and validation of lipid metabolism-associated lncRNAs and tumor immune microenvironment in bladder cancer

BACKGROUND

Numerous types of research revealed that long noncoding RNAs (lncRNAs) played a significant role in immune response and the tumor microenvironment of bladder cancer (BLCA). Dysregulated lipid metabolism is considered to be one of the major risk factors for BLCA, the study aimed to detect the lipid metabolism-related lncRNAs (LMRLs) along with their potential prognostic values and immune correlations in BLCA.

METHODS

We collected lipid metabolism-related genes, expression profiles, and clinical information on BLCA from the Molecular Signature Database (MSigDB) and the TCGA database, respectively. Differentially expressed lipid metabolism genes (DE-LMRGs) and differentially expressed long non-coding RNAs (DE-lncRNAs) were selected using the limma package. Spearman correlation analysis was employed to explore the correlations between DE-lncRNAs and DE-LMRGs and to further develop protein-protein interaction (PPI) networks and perform mutational analysis. The least absolute shrinkage and selection operator (LASSO) and univariate Cox analysis were then employed to construct a prognostic risk model. The performance of the model was evaluated using Kaplan-Meier survival analysis, receiver operating characteristic (ROC) curves, and consistency indices. In addition, we downloaded the GSE31684 dataset for external validation of the prognostic signature. Moreover, we explored the association of the risk model with immune cell infiltration and chemotherapy response analysis to reveal the tumor immune microenvironment of BLCA. Finally, RT-qPCR was utilized to validate the expression of prognostic genes.

RESULTS

A total of 48 DE-LncRNAs and 33 DE-LMRGs were found to be robustly correlated, and were used to construct a lncRNA-mRNA co-expression network, in which ACACB, ACOX2, and BCHE showed high mutation rates. Then, a risk model based on three LMRLs (RP11-465B22.8, MIR100HG, and LINC00865) was constructed. The risk model effectively distinguished between the clinical outcomes of BLCA patients, with high-risk scores indicating a worse prognosis and with substantial prognostic prediction accuracy. The model's results were consistent in the GSE31684 dataset. In addition, a nomogram was constructed based on the risk score, age, pathological T-stage, and pathological N-stage, which showed robust predictive power. Immune landscape analysis indicated that the risk model was significantly associated with T-cell CD4 memory activation, M1 macrophage, M2 macrophage, dendritic cell activation, and T-cell regulatory. We predicted that 49 drugs would perform satisfactorily in the high-risk group. Additionally, we found five m6A regulators associated with the high- and low-risk groups, suggesting that upstream regulation of LncRNA could be a novel target for BLCA treatment. Finally, RT-qPCR showed that RP11-465B22.8 was highly expressed in BLCA, while MIR100HG and LINC00865 were downregulated in BLCA.

CONCLUSION

Our findings suggest that the three LMRLs may serve as potential prognostic and immunotherapeutic biomarkers in BLCA. In addition, our study provides new ideas for understanding the pathogenic mechanisms and developing therapeutic strategies for BLCA patients.

Roles of the HIF-1α pathway in the development and progression of keloids

Keloids, a pathological scar that is induced by the consequence of aberrant wound healing, is still a major global health concern for its unsatisfactory treatment outcomes. HIF-1α, a main regulator of hypoxia, mainly acts through some proteins or signaling pathways and plays important roles in a variety of biological processes. Accumulating evidence has shown that HIF-1α played a crucial role in the process of keloid formation. In this review, we attempted to summarize the current knowledge on the association between HIF-1α expression and the development and progression of keloids. Through a comprehensive analysis, the molecular mechanisms underlying HIF-1α in keloids were shown to be correlated to the proliferation of fibroblasts, angiogenesis, and collagen deposits. The affected proteins and the signaling pathways were multiple. For instance, HIF-1α was reported to promote keloids formation by enhancing angiogenesis, fibroblast proliferation, and collagen deposition through the activation of periostin PI3K/Akt, TGF-β/Smad and TLR4/MyD88/NF-κB pathway. However, the specific effects of HIF-1α on keloids keloid illnesses in clinical practice is are entirely unclear, and further studies in clinical trials are still warranted. Therefore, an in-depth understanding of the biological mechanisms of HIF-1α in keloid formation is significant to develop promising therapeutic targets for the treatment of keloids in clinical practice.

A Novel Prognostic Signature of comprising Nine NK Cell signatures Based on Both Bulk RNA Sequencing and Single-Cell RNA Sequencing for Hepatocellular Carcinoma

Background: Hepatocellular carcinoma (HCC) has limited prognostic prediction due to its heterogeneity. Understanding the role of natural killer (NK) cells in HCC is vital for prognosis and immunotherapy guidance. We aimed to identify NK cell marker genes through scRNA-seq and develop a prognostic signature for HCC. Methods: We analyzed scRNA-seq data (GSE149614) from 10 patients and bulk RNA-seq data from 786 patients with clinicopathological information. NK cell marker genes were identified using clustering and marker finding functions. A predictive risk signature was constructed using LASSO-COX algorithm. Functional annotations and immune cell infiltration analysis were performed, and the nomogram's performance was evaluated. Results: We identified 79 NK cell marker genes associated with NK cell-mediated cytotoxicity, apoptosis, and immune response. The multigene signature significantly correlated with overall survival (OS) in TCGA-LIHC cohort and was validated in other cohorts. Low-risk patients exhibited higher immune cell infiltration, including CD8+ T cells. The risk signature was an independent prognostic factor for OS (HR > 1, p < 0.001). The nomogram combining the risk signature and clinical predictors demonstrated robust prognostic ability. Conclusion: We developed a nine-gene signature prognostic model based on NK cell marker genes to accurately assess the prognostic risk of HCC. This model can be a valuable tool for personalized evaluation post-surgery. Our study underscores the potential of NK cells in HCC prognosis and highlights the importance of scRNA-seq analysis in identifying prognostic markers.

FAM201A encodes small protein NBASP to inhibit neuroblastoma progression via inactivating MAPK pathway mediated by FABP5

Increasing evidence indicates that long non-coding RNA (lncRNA) is one of the most important RNA regulators in the pathogenesis of neuroblastoma (NB). Here, we found that FAM201A was low expressed in NB and a variety of gain and loss of function studies elucidated the anti-tumor effects of FAM201A on the regulation of proliferation, migration and invasion of NB cells. Intriguingly, we identified the ability of FAM201A to encode the tumor-suppressing protein, NBASP, which interacted with FABP5 and negatively regulated its expression. In vivo assays also revealed NBASP repressed NB growth via inactivating MAPK pathway mediated by FABP5. In conclusion, our findings demonstrated that NBASP encoded by FAM201A played a tumor-suppressor role in NB carcinogenesis via down-regulating FABP5 to inactivate the MAPK pathway. These results extended our understanding of the relationship of lncRNA-encoded functional peptides and plasticity of tumor progression.

Unveiling the MUFA-Cancer Connection: Insights from Endogenous and Exogenous Perspectives

Monounsaturated fatty acids (MUFAs) have been the subject of extensive research in the field of cancer due to their potential role in its prevention and treatment. MUFAs can be consumed through the diet or endogenously biosynthesized. Stearoyl-CoA desaturases (SCDs) are key enzymes involved in the endogenous synthesis of MUFAs, and their expression and activity have been found to be increased in various types of cancer. In addition, diets rich in MUFAs have been associated with cancer risk in epidemiological studies for certain types of carcinomas. This review provides an overview of the state-of-the-art literature on the associations between MUFA metabolism and cancer development and progression from human, animal, and cellular studies. We discuss the impact of MUFAs on cancer development, including their effects on cancer cell growth, migration, survival, and cell signaling pathways, to provide new insights on the role of MUFAs in cancer biology.

Far upstream element-binding protein 1 confers lobaplatin resistance by transcriptionally activating PTGES and facilitating the arachidonic acid metabolic pathway in osteosarcoma

Drug resistance is a major obstacle in cancer treatment and recurrence prevention and leads to poor outcomes in patients suffering from osteosarcoma. Clarification of the mechanism of drug resistance and exploration of effective strategies to overcome this obstacle could lead to clinical benefits for these patients. The expression of far upstream element-binding protein 1 (FUBP1) was found to be markedly elevated in osteosarcoma cell lines and clinical specimens compared with osteoblast cells and normal bone specimens. High expression of FUBP1 was correlated with a more aggressive phenotype and a poor prognosis in osteosarcoma patients. We found that overexpression of FUBP1 confers lobaplatin resistance, whereas the inhibition of FUBP1 sensitizes osteosarcoma cells to lobaplatin-induced cytotoxicity both in vivo and in vitro. Chromatin immunoprecipitation-seq and RNA-seq were performed to explore the potential mechanism. It was revealed that FUBP1 could regulate the transcription of prostaglandin E synthase (PTGES) and subsequently activate the arachidonic acid (AA) metabolic pathway, which leads to resistance to lobaplatin. Our investigation provides evidence that FUBP1 is a potential therapeutic target for osteosarcoma patients. Targeting FUBP1, its downstream target PTGES and the AA metabolic pathway may be promising strategies for sensitizing chemoresistant osteosarcoma cells to lobaplatin.

The emerging role of fatty acid binding protein 5 (FABP5) in cancers

Fatty acid binding protein 5 (FABP5, or epidermal FABP) is an intracellular chaperone of fatty acid molecules that regulates lipid metabolism and cell growth. In patient-derived tumours, FABP5 expression is increased up to tenfold, often co-expressed with other cancer-related proteins. High tumoral FABP5 expression is associated with poor prognosis. FABP5 activates transcription factors (TFs) leading to increased expression of proteins involved in tumorigenesis. Genetic and pharmacological preclinical studies show that inhibiting FABP5 reduces protumoral markers, whereas elevation of FABP5 promotes tumour growth and spread. Thus, FABP5 might be a valid target for novel therapeutics. The evidence base is currently strongest for liver, prostate, breast, and brain cancers, and squamous cell carcinoma (SCC), which could represent relevant patient populations for any drug discovery programme. Teaser: This review presents the growing evidence that upregulated fatty acid binding protein 5 (FABP5) plays a role in the progression of multiple cancer types, and may represent a novel therapeutic target.

Lycorine induces apoptosis of acute myeloid leukemia cells and inhibits triglyceride production via binding and targeting FABP5

Acute myeloid leukemia (AML) is the most common hematopoietic malignancy with abnormal lipid metabolism. However, currently available information on the involvement of the alterations in lipid metabolism in AML development is limited. In this study, we demonstrate that FABP5 expression facilitates AML cell viability, protects AML cells from apoptosis, and maintains triglyceride production. Our bioinformatics analysis revealed that FABP5 expression was upregulated and correlated with unfavorable overall survival of AML patients. FABP5 expression may be used to distinguish normal and AML with high accuracy. FABP5-based risk score was an independent risk factor for AML patients. AML patients with highly expressed FABP5 predicted resistance to drugs. In vitro study showed that FABP5 expression was remarkably elevated in primary AML blasts and an AML cell line. Silencing FABP5 expression attenuated AML cell viability, reduced triglyceride production and lipid droplet accumulation, and induced apoptosis. We utilized AutoDock online tool to identify lycorine as an FABP5 inhibitor by binding FABP5 at amino acid residues Ile54, Thr56, Thr63, and Arg109. Lycorine treatment downregulated the expression levels of FABP5 and its target PPARγ, impaired AML cell viability, triggered apoptosis, and reduced triglyceride production in AML cells. These results demonstrate that FABP5 is critical for AML cell survival and highlight a novel metabolic vulnerability for AML.

Spatial transcriptomics reveals the heterogeneity and FGG+CRP+ inflammatory cancer-associated fibroblasts replace islets in pancreatic ductal adenocarcinoma

BACKGROUND

Understanding the spatial heterogeneity of the tumor microenvironment (TME) in pancreatic cancer (PC) remains challenging.

METHODS

In this study, we performed spatial transcriptomics (ST) to investigate the gene expression features across one normal pancreatic tissue, PC tissue, adjacent tumor tissue, and tumor stroma. We divided 18,075 spatial spots into 22 clusters with t-distributed stochastic neighbor embedding based on gene expression profiles. The biological functions and signaling pathways involved in each cluster were analyzed with gene set enrichment analysis.

RESULTS

The results revealed that KRT13+FABP5+ malignant cell subpopulation had keratinization characteristics in the tumor tissue. Fibroblasts from adjacent tumor tissue exhibited a tumor-inhibiting role such as "B-cell activation" and "positive regulation of leukocyte activation." The FGG+CRP+ inflammatory cancer-associated fibroblasts replaced the islets in tumor stroma. During PC progression, the damage to pancreatic structure and function was heavier in the pancreatic exocrine (AMYA2+PRSS1+) than in the endocrine (INS+GCG+).

CONCLUSION

Our results revealed the spatial heterogeneity of dynamic changes and highlighted the significance of impaired exocrine function in PC.

The role of hypoxia-inducible factor 1α in hepatic lipid metabolism

Chronic liver disease is a major public health problem with a high and increasing prevalence worldwide. In the progression of chronic liver disease, steatosis drives the progression of the disease to cirrhosis or even liver cancer. Hypoxia-inducible factor 1α (HIF-1α) is central to the regulation of hepatic lipid metabolism. HIF-1α upregulates the expression of genes related to lipid uptake and synthesis in the liver and downregulates the expression of lipid oxidation genes. Thus, it promotes intrahepatic lipid deposition. In addition, HIF-1α is expressed in white adipose tissue, where lipolysis releases free fatty acids (FFAs) into the blood. These circulating FFAs are taken up by the liver and accumulate in the liver. The expression of HIF-1α in the liver condenses bile and makes it easier to form gallstones. Contrary to the role of hepatic HIF-1α, intestinal HIF-1α expression can maintain a healthy microbiota and intestinal barrier. Thus, it plays a protective role against hepatic steatosis. This article aims to provide an overview of the current understanding of the role of HIF-1α in hepatic steatosis and to encourage the development of therapeutic agents associated with HIF-1α pathways. KEY MESSAGES: • Hepatic HIF-1α expression promotes lipid uptake and synthesis and reduces lipid oxidation leading to hepatic steatosis. • The expression of HIF-1α in the liver condenses bile and makes it easier to form gallstones. • Intestinal HIF-1α expression can maintain a healthy microbiota and intestinal barrier.

Fatty acid metabolism: A new therapeutic target for cervical cancer

Cervical cancer (CC) is one of the most common malignancies in women. Cancer cells can use metabolic reprogramming to produce macromolecules and ATP needed to sustain cell growth, division and survival. Recent evidence suggests that fatty acid metabolism and its related lipid metabolic pathways are closely related to the malignant progression of CC. In particular, it involves the synthesis, uptake, activation, oxidation, and transport of fatty acids. Similarly, more and more attention has been paid to the effects of intracellular lipolysis, transcriptional regulatory factors, other lipid metabolic pathways and diet on CC. This study reviews the latest evidence of the link between fatty acid metabolism and CC; it not only reveals its core mechanism but also discusses promising targeted drugs for fatty acid metabolism. This study on the complex relationship between carcinogenic signals and fatty acid metabolism suggests that fatty acid metabolism will become a new therapeutic target in CC.

Oncogenic role and potential regulatory mechanism of fatty acid binding protein 5 based on a pan-cancer analysis

As one member of fatty acid binding proteins (FABPs), FABP5 makes a contribution in the occurrence and development of several tumor types, but existing analysis about FABP5 and FABP5-related molecular mechanism remains limited. Meanwhile, some tumor patients showed limited response rates to current immunotherapy, and more potential targets need to be explored for the improvement of immunotherapy. In this study, we made a pan-cancer analysis of FABP5 based on the clinical data from The Cancer Genome Atlas database for the first time. FABP5 overexpression was observed in many tumor types, and was statistically associated with poor prognosis of several tumor types. Additionally, we further explored FABP5-related miRNAs and corresponding lncRNAs. Then, miR-577-FABP5 regulatory network in kidney renal clear cell carcinoma as well as CD27-AS1/GUSBP11/SNHG16/TTC28-AS1-miR-22-3p-FABP5 competing endogenous RNA regulatory network in liver hepatocellular carcinoma were constructed. Meanwhile, Western Blot and reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) analysis were used to verify miR-22-3p-FABP5 relationship in LIHC cell lines. Moreover, the potential relationships of FABP5 with immune infiltration and six immune checkpoints (CD274, CTLA4, HAVCR2, LAG3, PDCD1 and TIGIT) were discovered. Our work not only deepens the understanding of FABP5's functions in multiple tumors and supplements existing FABP5-related mechanisms, but also provides more possibilities for immunotherapy.

Hepatocyte ferroptosis contributes to anti-tuberculosis drug-induced liver injury: Involvement of the HIF-1α/SLC7A11/GPx4 axis

Anti-tuberculosis drug-induced liver injury (ATB-DILI) is a common serious adverse event observed during the clinical treatment of tuberculosis. However, the molecular mechanisms underlying ATB-DILI remain unclear. A recent study has indicated that ferroptosis and lipid peroxidation may be involved in liver injury. Therefore, this study aimed to investigate the role of ferroptosis in the molecular mechanisms underlying ATB-DILI. Our results showed that anti-TB drugs induced hepatocyte damage in vivo and in vitro and inhibited BRL-3A cell activity in a dose-dependent manner, accompanied by increased lipid peroxidation and reduced antioxidant levels. Moreover, ACSL4 expression and Fe²⁺ concentration significantly increased following anti-TB drug treatment. Interestingly, anti-TB drug-induced hepatocyte damage was reversed by ferrostatin-1 (Fer-1, a specific ferroptosis inhibitor). In contrast, treatment with erastin (a ferroptosis inducer) resulted in further elevation of ferroptosis indicators. Additionally, we also found that anti-TB drug treatment inhibited HIF-1α/SLC7A11/GPx4 signaling in vivo and in vitro. Notably, HIF-1α knockdown significantly enhanced anti-TB drug-induced ferroptotic events and the subsequent exacerbation of hepatocyte damage. In conclusion, our findings indicated that ferroptosis plays a crucial role in the development of ATB-DILI. Furthermore, anti-TB drug-induced hepatocyte ferroptosis was shown to be regulated by HIF-1α/SLC7A11/GPx4 signaling. These findings shed new light on the mechanisms underlying ATB-DILI and suggest novel therapeutic strategies for this disease.

Transcriptional Response to Hypoxia: The Role of HIF-1-Associated Co-Regulators

The Hypoxia Inducible Factor 1 (HIF-1) plays a major role in the cellular response to hypoxia by regulating the expression of many genes involved in adaptive processes that allow cell survival under low oxygen conditions. Adaptation to the hypoxic tumor micro-environment is also critical for cancer cell proliferation and therefore HIF-1 is also considered a valid therapeutical target. Despite the huge progress in understanding regulation of HIF-1 expression and activity by oxygen levels or oncogenic pathways, the way HIF-1 interacts with chromatin and the transcriptional machinery in order to activate its target genes is still a matter of intense investigation. Recent studies have identified several different HIF-1- and chromatin-associated co-regulators that play important roles in the general transcriptional activity of HIF-1, independent of its expression levels, as well as in the selection of binding sites, promoters and target genes, which, however, often depends on cellular context. We review here these co-regulators and examine their effect on the expression of a compilation of well-characterized HIF-1 direct target genes in order to assess the range of their involvement in the transcriptional response to hypoxia. Delineating the mode and the significance of the interaction between HIF-1 and its associated co-regulators may offer new attractive and specific targets for anticancer therapy.

Metabolic Hijacking of Hexose Metabolism to Ascorbate Synthesis Is the Unifying Biochemical Basis of Murine Liver Fibrosis

We wished to understand the metabolic reprogramming underlying liver fibrosis progression in mice. Administration to male C57BL/6J mice of the hepatotoxins carbon tetrachloride (CCl4), thioacetamide (TAA), or a 60% high-fat diet, choline-deficient, amino-acid-defined diet (HF-CDAA) was conducted using standard protocols. Livers collected at different times were analyzed by gas chromatography-mass spectrometry-based metabolomics. RNA was extracted from liver and assayed by qRT-PCR for mRNA expression of 11 genes potentially involved in the synthesis of ascorbic acid from hexoses, Gck, Adpgk, Hk1, Hk2, Ugp2, Ugdh, Ugt1a1, Akr1a4, Akr1b3, Rgn and Gulo. All hepatotoxins resulted in similar metabolic changes during active fibrogenesis, despite different etiology and resultant scarring pattern. Diminished hepatic glucose, galactose, fructose, pentose phosphate pathway intermediates, glucuronic acid and long-chain fatty acids were compensated by elevated ascorbate and the product of collagen prolyl 4-hydroxylase, succinate and its downstream metabolites fumarate and malate. Recovery from the HF-CDAA diet challenge (F2 stage fibrosis) after switching to normal chow was accompanied by increased glucose, galactose, fructose, ribulose 5-phosphate, glucuronic acid, the ascorbate metabolite threonate and diminished ascorbate. During the administration of CCl4, TAA and HF-CDAA, aldose reductase Akr1b3 transcription was induced six- to eightfold, indicating increased conversion of glucuronic acid to gulonic acid, a precursor of ascorbate synthesis. Triggering hepatic fibrosis by three independent mechanisms led to the hijacking of glucose and galactose metabolism towards ascorbate synthesis, to satisfy the increased demand for ascorbate as a cofactor for prolyl 4-hydroxylase for mature collagen production. This metabolic reprogramming and causal gene expression changes were reversible. The increased flux in this pathway was mediated predominantly by increased transcription of aldose reductase Akr1b3.

Macrophage-Derived 25-Hydroxycholesterol Promotes Vascular Inflammation, Atherogenesis, and Lesion Remodeling

BACKGROUND

Cross-talk between sterol metabolism and inflammatory pathways has been demonstrated to significantly affect the development of atherosclerosis. Cholesterol biosynthetic intermediates and derivatives are increasingly recognized as key immune regulators of macrophages in response to innate immune activation and lipid overloading. 25-Hydroxycholesterol (25-HC) is produced as an oxidation product of cholesterol by the enzyme cholesterol 25-hydroxylase (CH25H) and belongs to a family of bioactive cholesterol derivatives produced by cells in response to fluctuating cholesterol levels and immune activation. Despite the major role of 25-HC as a mediator of innate and adaptive immune responses, its contribution during the progression of atherosclerosis remains unclear.

METHODS

The levels of 25-HC were analyzed by liquid chromatography-mass spectrometry, and the expression of CH25H in different macrophage populations of human or mouse atherosclerotic plaques, respectively. The effect of CH25H on atherosclerosis progression was analyzed by bone marrow adoptive transfer of cells from wild-type or Ch25h-/- mice to lethally irradiated Ldlr-/- mice, followed by a Western diet feeding for 12 weeks. Lipidomic, transcriptomic analysis and effects on macrophage function and signaling were analyzed in vitro from lipid-loaded macrophage isolated from Ldlr-/- or Ch25h-/-;Ldlr-/- mice. The contribution of secreted 25-HC to fibrous cap formation was analyzed using a smooth muscle cell lineage-tracing mouse model, Myh11ERT2CREmT/mG;Ldlr-/-, adoptively transferred with wild-type or Ch25h-/- mice bone marrow followed by 12 weeks of Western diet feeding.

RESULTS

We found that 25-HC accumulated in human coronary atherosclerotic lesions and that macrophage-derived 25-HC accelerated atherosclerosis progression, promoting plaque instability through autocrine and paracrine actions. 25-HC amplified the inflammatory response of lipid-loaded macrophages and inhibited the migration of smooth muscle cells within the plaque. 25-HC intensified inflammatory responses of lipid-laden macrophages by modifying the pool of accessible cholesterol in the plasma membrane, which altered Toll-like receptor 4 signaling, promoted nuclear factor-κB-mediated proinflammatory gene expression, and increased apoptosis susceptibility. These effects were independent of 25-HC-mediated modulation of liver X receptor or SREBP (sterol regulatory element-binding protein) transcriptional activity.

CONCLUSIONS

Production of 25-HC by activated macrophages amplifies their inflammatory phenotype, thus promoting atherogenesis.

HCC: RNA-Sequencing in Cirrhosis

Hepatocellular carcinoma (HCC) ranks the most common types of cancer worldwide. As the fourth leading cause of cancer-related deaths, its prognosis remains poor. Most patients developed HCC on the basis of chronic liver disease. Cirrhosis is an important precancerous lesion for HCC. However, the molecular mechanisms in HCC development are still unclear. To explore the changes at the level of transcriptome in this process, we performed RNA-sequencing on cirrhosis, HCC and paracancerous tissues. Continuously changing mRNA was identified using Mfuzz cluster analysis, then their functions were explored by enrichment analyses. Data of cirrhotic HCC patients were obtained from TCGA, and a fatty acid metabolism (FAM)-related prognostic signature was then established. The performance and immunity relevance of the signature were verified in internal and external datasets. Finally, we validated the expression and function of ADH1C by experiments. As a result, 2012 differently expressed mRNA were identified by RNA-sequencing and bioinformatics analyses. Fatty acid metabolism was identified as a critical pathway by enrichment analyses of the DEGs. A FAM-related prognostic model and nomogram based on it were efficient in predicting the prognosis of cirrhotic HCC patients, as patients with higher risk scores had shorter survival time. Risk scores calculated by the signature were then proved to be associated with a tumor immune environment. ADH1C were downregulated in HCC, while silence of ADH1C could significantly promote proliferation and motility of the HCC cell line.

Gradual deterioration of fatty liver disease to liver cancer via inhibition of AMPK signaling pathways involved in energy-dependent disorders, cellular aging, and chronic inflammation

Introduction

Hepatocellular carcinoma (HCC) is the most prevalent primary liver cancer kind. According to recent research, a fatty liver increases the risk of hepatocellular cancer. Nevertheless, the AMPK signaling pathway is crucial. In addition, 5'-AMP-activated protein kinase (AMPK) is strongly linked to alterations in the tumor microenvironment, such as inflammation, hypoxia, and aging. The objective of this study is to evaluate the impact of the AMPK signaling pathway on the progression of fatty liver to HCC.

Methods

In this study, we established a mouse liver cancer model using high-fat diets and nano-nitrosamines (nano-DEN). In addition, we employed a transcriptomic technique to identify all mRNAs detected in liver samples at the 25th weekexpression of proteins linked with the LKB1-AMPK-mTOR signaling pathway, inflammation, aging, and hypoxia was studied in microarrays of liver cancer tissues from mice and humans. These proteins included p-AMPK, LKB1, mTOR, COX-2, β-catenin, HMGB1, p16, and HIF-1α.

Results

Data were collected at different times in the liver as well as in cancerous and paracancerous regions and analyzed by a multispectral imaging system. The results showed that most of the genes in the AMPK signaling pathway were downregulated. Prakk1 expression was upregulated compared to control group but downregulated in the cancerous regions compared to the paracancerous regions. Stk11 expression was downregulated in the cancerous regions. Mtor expression was upregulated in the cancerous regions. During liver cancer formation, deletion of LKB1 in the LKB1-AMPK-mTOR signaling pathway reduces phosphorylation of AMPK. It contributed to the upregulation of mTOR, which further led to the upregulation of HIF1α. In addition, the expression of β-catenin, COX-2, and HMGB1 were upregulated, as well as the expression of p16 was downregulated.

Discussion

These findings suggest that changes in the AMPK signaling pathway exacerbate the deterioration of disrupted energy metabolism, chronic inflammation, hypoxia, and cellular aging in the tumor microenvironment, promoting the development of fatty liver into liver cancer.

Fatty acid binding protein 5 promotes the proliferation, migration, and invasion of hepatocellular carcinoma cells by degradation of Krüppel-like factor 9 mediated by miR-889-5p via cAMP-response element binding protein

Mounting evidence has demonstrated that fatty acid binding protein 5 (FABP5) is commonly upregulated in many human malignancies. However, the mechanisms explaining the involvement of FABP5 in hepatocellular carcinoma (HCC) remain unclear. In this study, we demonstrated the involvement of FABP5 and its downstream signaling molecules in HCC progression. We first confirmed that FABP5 expression was upregulated in HCC. Additionally, FABP5 promoted HCC cells proliferation, migration, and invasion. Mechanistic investigation showed that FABP5 could improve cAMP-response element binding protein (CREB) phosphorylation. Meanwhile, CREB, as a transcription factor, upregulated the miR-889-5p expression by binding to the miR-889-5p promoter region. Consequently, miR-889-5p led to downregulation of Krüppel-like factor 9 (KLF9) by binding to the 3ʹ-UTR of the KLF9 mRNA, potentiating the PI3K/AKT signaling pathway and promoting the proliferation, migration, and invasion of HCC cells. Our findings have identified a FABP5/CREB/miR-889-5p/KLF9 axis for HCC progression, and we postulate that blocking this key signaling pathway may represent a promising strategy for HCC treatment.

Exosomal miR-1304-3p promotes breast cancer progression in African Americans by activating cancer-associated adipocytes

Breast cancer displays disparities in mortality between African Americans and Caucasian Americans. However, the exact molecular mechanisms remain elusive. Here, we identify miR-1304-3p as the most upregulated microRNA in African American patients. Importantly, its expression significantly correlates with poor progression-free survival in African American patients. Ectopic expression of miR-1304 promotes tumor progression in vivo. Exosomal miR-1304-3p activates cancer-associated adipocytes that release lipids and enhance cancer cell growth. Moreover, we identify the anti-adipogenic gene GATA2 as the target of miR-1304-3p. Notably, a single nucleotide polymorphism (SNP) located in the miR-1304 stem-loop region shows a significant difference in frequencies of the G allele between African and Caucasian American groups, which promotes the maturation of miR-1304-3p. Therefore, our results reveal a mechanism of the disparity in breast cancer progression and suggest a potential utility of miR-1304-3p and the associated SNP as biomarkers for predicting the outcome of African American patients.

Cholangiocarcinoma progression depends on the uptake and metabolization of extracellular lipids

BACKGROUND AND AIMS

Cholangiocarcinoma (CCA) includes a heterogeneous group of biliary cancers with a dismal prognosis. We investigated if lipid metabolism is disrupted in CCA and its role in tumor proliferation.

APPROACH AND RESULTS

The in vitro and in vivo tumorigenic capacity of five human CCA cell lines was analyzed. Proteome, lipid content, and metabolic fluxes were evaluated in CCA cells and compared with normal human cholangiocytes (NHC). The Akt1/NOTCH1 intracellular cytoplasmic domain (Nicd1)-driven CCA mouse model was also evaluated. The proteome of CCA cells was enriched in pathways involved in lipid and lipoprotein metabolism. The EGI1 CCA cell line presented the highest tumorigenic capacity. Metabolic studies in high (EGI1) versus low (HUCCT1) proliferative CCA cells in vitro showed that both EGI1 and HUCCT1 incorporated more fatty acids (FA) than NHC, leading to increased triglyceride storage, also observed in Akt1/Nicd1-driven CCA mouse model. The highly proliferative EGI1 CCA cells showed greater uptake of very-low-density and HDLs than NHC and HUCCT1 CCA cells and increased cholesteryl ester content. The FA oxidation (FAO) and related proteome enrichment were specifically up-regulated in EGI1, and consequently, pharmacological blockade of FAO induced more pronounced inhibition of their tumorigenic capacity compared with HUCCT1. The expression of acyl-CoA dehydrogenase ACADM, the first enzyme involved in FAO, was increased in human CCA tissues and correlated with the proliferation marker PCNA.

CONCLUSIONS

Highly proliferative human CCA cells rely on lipid and lipoprotein uptake to fuel FA catabolism, suggesting that inhibition of FAO and/or lipid uptake could represent a therapeutic strategy for this CCA subclass.

scAB detects multiresolution cell states with clinical significance by integrating single-cell genomics and bulk sequencing data

Although single-cell sequencing has provided a powerful tool to deconvolute cellular heterogeneity of diseases like cancer, extrapolating clinical significance or identifying clinically-relevant cells remains challenging. Here, we propose a novel computational method scAB, which integrates single-cell genomics data with clinically annotated bulk sequencing data via a knowledge- and graph-guided matrix factorization model. Once combined, scAB provides a coarse- and fine-grain multiresolution perspective of phenotype-associated cell states and prognostic signatures previously not visible by single-cell genomics. We use scAB to enhance live cancer single-cell RNA-seq data, identifying clinically-relevant previously unrecognized cancer and stromal cell subsets whose signatures show a stronger poor-survival association. The identified fine-grain cell subsets are associated with distinct cancer hallmarks and prognosis power. Furthermore, scAB demonstrates its utility as a biomarker identification tool, with the ability to predict immunotherapy, drug responses and survival when applied to melanoma single-cell RNA-seq datasets and glioma single-cell ATAC-seq datasets. Across multiple single-cell and bulk datasets from different cancer types, we also demonstrate the superior performance of scAB in generating prognosis signatures and survival predictions over existing models. Overall, scAB provides an efficient tool for prioritizing clinically-relevant cell subsets and predictive signatures, utilizing large publicly available databases to improve prognosis and treatments.

Metabolite activation of tumorigenic signaling pathways in the tumor microenvironment

The role of metabolites exchanged in the tumor microenvironment is largely thought of as fuels to drive the increased biosynthetic and bioenergetic demands of growing tumors. However, this view is shifting as metabolites are increasingly shown to function as signaling molecules that directly regulate oncogenic pathways. Combined with our growing understanding of the essential role of stromal cells, this shift has led to increased interest in how the collective and interconnected metabolome of the tumor microenvironment can drive malignant transformation, epithelial-to-mesenchymal transition, drug resistance, immune evasion, and metastasis. In this review, we discuss how metabolite exchange between tumors and various cell types in the tumor microenvironment—such as fibroblasts, adipocytes, and immune cells—can activate signaling pathways that drive cancer progression.

LncRNA colorectal neoplasia differentially expressed promotes glycolysis of liver cancer cells by regulating hypoxia-inducible factor 1α

LncRNAs are associated with tumorigenesis of liver cancer. LncRNA Colorectal Neoplasia Differentially Expressed (CRNDE) was identified as an oncogenic lncRNA and involved in tumor growth and metastasis. The role of CRNDE in liver cancer was investigated. CRNDE was elevated in liver cancer cells. Knockdown of CRNDE decreased cell viability and inhibited proliferation of liver cancer. Moreover, knockdown of CRNDE reduced levels of extracellular acidification rate, glucose consumption, and lactate production to repress glycolysis of liver cancer. Silence of CRNDE enhanced the expression of miR-142 and reduced enhancer of zeste homolog 2 (EZH2) and hypoxia-inducible factor 1α (HIF-1α). Over-expression of HIF-1α attenuated CRNDE silence-induced decrease of glucose consumption and lactate production. Injection with sh-CRNDE virus reduced in vivo tumor growth of liver cancer through up-regulation of miR-142 and down-regulation of EZH2 and HIF-1α. In conclusion, knockdown of CRNDE suppressed cell proliferation, glycolysis, and tumor growth of liver cancer through EZH2/miR-142/HIF-1α.