FABP5 correlates with poor prognosis and promotes tumor cell growth and metastasis in cervical cancer

Circadian rhythm and aryl hydrocarbon receptor crosstalk in bone marrow adipose tissue and implications in leukemia

Leukemic cells modulate the bone marrow microenvironment to enhance their survival. Lipolysis in bone marrow adipose tissue (BMAT) has emerged as a critical factor supporting leukemic cell survival, yet understanding its primary role in leukemia development remains limited. Fanconi anemia (FA), characterized by a predisposition to acute myeloid leukemia (AML) and hypersensitivity to environmental toxins, is a transitional model for studying leukemic transformation. İntegrated multi-omics analyses were conducted on BMAT-derived mesenchymal stem/stromal cells (MSCs) from healthy donors (HD), AML, and FA patients. These analyses revealed intricate interactions among genes, metabolites, and lipids. Particularly noteworthy were the effects observed following the inhibition of aryl hydrocarbon receptor (AhR) signaling by StemRegenin1 (SR1). BMAT-MSCs showed increased expression of epithelial-mesenchymal transition (EMT) genes in FA and AML, suggesting a potential shift towards cancer-associated fibroblasts in the dysregulated marrow microenvironment. Identification of potential circadian rhythm biomarkers (NPAS2, PER2, BHLHE40, PER3, CIART) in BMAT-MSCs indicates a link between related lipid metabolism genes (e.g., PTGS1, PIK3R1) and SR1 treatment, implicating them in lipolysis processes. Dysregulation of circadian rhythm-related genes (CIART, BHLHE40, NPAS2) in AML BMAT-MSCs, along with changes in circulating lipid metabolites like palmitate suggests their role in shaping the leukemia microenvironment. Upregulation of FABP5 and CD36 suggests a novel molecular mechanism involving FABP5 in AhR-mediated circadian regulation and identifies CD36 as a potential partner for FABP5 in BMAT-MSCs. Overall, this study unveils the interplay between AhR signaling, circadian rhythm, and the leukemia microenvironment in BMAT-MSCs, offering new insights into leukemia pathogenesis and therapeutic opportunities.

Ubiquitination in lipid metabolism reprogramming: implications for pediatric solid tumors

Pediatric solid tumors represent a significant subset of childhood cancers, accounting for approximately 60% of new diagnoses. Despite advancements in therapeutic strategies, survival rates remain markedly disparate between high-income and resource-limited settings, underscoring the urgent need for novel and effective treatments. Lipid metabolic reprogramming is a fundamental hallmark of cancer, driving tumor progression, therapeutic resistance, and immune evasion through enhanced fatty acid uptake, increased de novo lipid synthesis, and activated fatty acid β-oxidation (FAO). Ubiquitination, a dynamic post-translational modification mediated by the ubiquitin-proteasome system (UPS), plays a crucial role in regulating lipid metabolism by modulating the stability and activity of key metabolic enzymes and transporters involved in cholesterol and fatty acid pathways. This review comprehensively examines the complex interplay between ubiquitination and lipid metabolic reprogramming in pediatric solid tumors. It delineates the mechanisms by which ubiquitination influences cholesterol biosynthesis, uptake, efflux, and fatty acid synthesis and oxidation, thereby facilitating tumor growth and survival. Furthermore, the review identifies potential UPS-mediated therapeutic targets and explores the feasibility of integrating ubiquitination-based strategies with existing treatments. By targeting the UPS to disrupt lipid metabolism pathways, novel therapeutic avenues may emerge to enhance treatment efficacy and overcome resistance in pediatric oncology. This synthesis of current knowledge aims to provide a foundation for the development of innovative, precision medicine approaches to improve clinical outcomes for children afflicted with solid tumors.

FABP5 is a key player in metabolic modulation and NF-κB dependent inflammation driving pleural mesothelioma

Pleural mesothelioma (PM) poses a significant challenge in oncology due to its intricate molecular and metabolic landscape, chronic inflammation, and heightened oxidative stress, which contribute to its notorious resilience and clinical complexities. Despite advancements, the precise mechanisms driving PM carcinogenesis remain elusive, impeding therapeutic progress. Here, we explore the interplay between tumor growth dynamics, lipid metabolism, and NF-κB dysregulation in malignant pleural mesothelioma, shedding light on novel molecular mechanisms underlying its pathogenesis. Our study reveals distinctive growth dynamics in PM cells, characterized by heightened proliferation, altered cell cycle progression, and resistance to apoptosis. Intriguingly, PM cells exhibit increased intracellular accumulation of myristic, palmitic, and stearic acids, suggestive of augmented lipid uptake and altered biosynthesis. Notably, we identify FABP5 as a key player in driving metabolic alterations and inflammation through NF-κB dysregulation in mesothelioma cells, distinguishing them from normal mesothelial cells. Silencing of FABP5 leads to significant alterations in cell dynamics, metabolism, and NF-κB activity, highlighting its potential as a therapeutic target. Our findings unveil a reciprocal relationship between lipid metabolism and inflammation in PM, providing a foundation for targeted therapeutic strategies. Overall, this comprehensive investigation offers insights into the intricate molecular mechanisms driving PM pathogenesis and identifies potential avenues for therapeutic intervention.

High-Glucose-Induced Metabolic and Redox Alterations Are Distinctly Modulated by Various Antidiabetic Agents and Interventions Against FABP5/7, MITF and ANGPTL4 in Melanoma A375 Cells

Hyperglycemia-induced effects on cellular metabolic properties and reactive oxygen species (ROS) generation play pivotal roles in the pathogenesis of malignant melanoma (MM). This study assessed how metabolic states, ROS production, and related gene expression are modulated by antidiabetic agents. The anti-diabetic agents metformin (Met) and imeglimin (Ime), inhibitors of fatty acid-binding proteins 5/7 (MF6) and microphthalmia-associated transcription factor (MITF) (ML329), and siRNA-mediated knockdown of angiopoietin-like protein 4 (ANGPTL4), which affect mitochondrial respiration, ROS production, and related gene expression, were tested in A375 (MM cell line) cells cultured in low (5.5 mM) and high glucose (50 mM) conditions. Cellular metabolic functions were significantly and differently modulated by Met, Ime, MF6, or ML329 and knockdown of ANGPTL4. High glucose significantly enhanced ROS production, which was alleviated by Ime but not by Met. Both MF6 and ML329 reduced ROS levels under both low and high glucose conditions. Knockdown of ANGPTL4 enhanced the change in glucose-dependent ROS production. Gene expression related to mitochondrial respiration and the pathogenesis of MM was significantly modulated by different glucose conditions, antidiabetic agents, MF6, and ML329. These findings suggest that glucose-dependent changes in cellular metabolism and redox status are differently modulated by antidiabetic agents, inhibition of fatty acid-binding proteins or MITF, and ANGPTL4 knockdown in A375 cells.

Fatty acid binding protein as a new age biomarker

Small lipid-binding proteins known as fatty acid-binding proteins (FABPs) are extensively expressed in cells having elevated levels of fatty acid (FA) metabolism. There are ten known FABPs in mammals that exhibit expression patterns specific to tissues and tertiary structures that are substantially preserved. FABPs were first investigated as FA transport proteins inside cells. Subsequent research has shown that they are involved in signalling within their expression cells and in metabolism of lipid, directly and through the control of expression of gene. Additionally, there is evidence that they might be released and influence circulatory function. It has been observed that some tissues and organs linked to inflammatory, metabolic illnesses and also infectious disease have markedly elevated expression levels of FABPs. Thus, in addition to previously identified markers, FABPs represent a promising new biomarker that require additional investigation to optimise illness detection and prognosis techniques.

Validation of endoplasmic reticulum stress-related gene signature to predict prognosis and immune landscape of patients with non-small cell lung cancer

BACKGROUND

Lung cancer is one of the most common cancers worldwide, with the incidence increasing each year. It is crucial to improve the prognosis of patients who have lung cancer. Non-Small Cell Lung Cancer (NSCLC) accounts for the majority of lung cancer. Though its prognostic significance in NSCLC has not been often documented, Endoplasmic Reticulum (ER) stress has been identified to be implicated in tumour malignant behaviours and resistance to treatment.

OBJECTIVE

This work aimed to develop a gene profile linked to ER stress that could be applied to predictive and risk assessment for non-small cell lung cancer.

METHODS

Data from 1014 NSCLC patients were sourced from The Cancer Genome Atlas (TCGA) database, integrating clinical and Ribonucleic Acid (RNA) information. Diverse analytical techniques were utilized to identify ERS-associated genes associated with patients' prognoses. These techniques included Kaplan-Meier analysis, univariate Cox regression, Least Absolute Shrinkage and Selection Operator regression analysis (LASSO) regression, and Pearson correlation analysis. Using a risk score model obtained from multivariate Cox analysis, a nomogram was created and validated to classify patients into high- and low-risk groups. The study employed the CIBERSORT algorithm and Single-Sample Gene Set Eenrichment Analysis (ssGSEA) to investigate the tumour immune microenvironment. We used the Genomics of Drug Sensitivity in Cancer (GDSC) database and R tools to identify medicines that could be responsive.

RESULTS

Four genes - FABP5, C5AR1, CTSL, and LTA4H - were chosen to create the risk model. Overall Survival (OS) was considerably lower (P< 0.05) in the high-risk group. When it came to predictive accuracy, the risk model outperformed clinical considerations. Several medication types that are sensitive to high-risk groups were chosen.

CONCLUSION

Our study has produced a gene signature associated with ER stress that may be employed to forecast the prognosis and therapeutic response of non-small cell lung cancer patients.

Glycolysis-Metabolism-Related Prognostic Signature for Ewing Sarcoma Patients

Ewing sarcoma (EwS) is a malignant sarcoma which occurs in bone and soft tissues commonly happening in children with poor survival rates. Changes in cell metabolism, such as glycolysis, may provide the environment for the transformation and progression of tumors. We aimed to build a model to predict prognosis of EwS patients based on glycolysis and metabolism genes. Candidate genes were obtained by differential gene expression analysis based on GSE17679, GSE17674 and ICGC datasets. We performed GO and KEGG pathway enrichment analysis on candidate genes. Univariate Cox and LASSO Cox regression analyses were conducted to construct a model to calculate the Risk Score. GSEA was done between high-risk and low-risk groups. CIBERSORT was applied to analyze the immune landscape. We got 295 candidate glycolysis-metabolism-related genes which were enriched in 620 GO terms and 18 KEGG pathways. 12 Genes were selected by univariate Cox model and 5 of them were determined by LASSO Cox regression analysis to be used in the construction of the Risk Score model. The Risk Score could be considered as an independent prognosis factor. The immune landscape and immune checkpoints' expression significantly differed between high- and low-risk groups. Our research constructed a new glycolysis-metabolism-related genes (FABP5, EMILIN1, GLCE, PHF11 and PALM3) based prognostic signature for EwS patients and assisted in gaining insight into prognosis to improve therapies further.

Concomitant decrease of E- and A-FABP expression predicts worse survival in urothelial bladder cancer patients

Non-muscle invasive bladder cancers (NMIBC) pTa-pT1 are depicted by a high risk of recurrence and/or progression with an unpredictable clinical evolution. Our aim was to identify, from the original resection specimen, tumors that will progress to better manage patients. We previously showed that A-FABP (Adipocyte- Fatty Acid Binding Protein) loss predicted NMIBC progression. Here we determined by immunohistochemistry the prognostic value of E-FABP (Epidermal-Fatty Acid Binding Protein) expression in 210 tumors (80 pTa, 75 pT1, 55 pT2-T4). Thus, E-FABP low expression was correlated with a high grade/stage, the presence of metastatic lymph nodes, and visceral metastases (p < 0.001). Unlike A-FABP in NMIBC, E-FABP low expression was not associated with RFS or PFS in Kaplan-Meier analysis. But patients of the overall cohort with a high E-FABP expression had a longer mOS (53.8 months vs. 29.3 months, p = 0.029). The immunohistochemical analysis on the same NMIBC tissue sections revealed that when A-FABP is absent, a high E-FABP expression is detected. E-FABP could compensate A-FABP loss. Interestingly, patients, whose original tumor presents both low E-FABP and negative A-FABP, had the worse survival, those maintaining the expression of both markers had better survival. To conclude, the combined evaluation of A- and E-FABP expression allowed to stratify patients with urothelial carcinoma for optimizing treatment and follow-up.

Resveratrol, a novel inhibitor of fatty acid binding protein 5, inhibits cervical cancer metastasis by suppressing fatty acid transport into nucleus and downstream pathways

BACKGROUND AND PURPOSE

Because of cervical cancer (CC) metastasis, the prognosis of diagnosed patients is poor. However, the molecular mechanisms and therapeutic approach for metastatic CC remain elusive.

EXPERIMENTAL APPROACH

In this study, we first evaluated the effect of resveratrol (RSV) on CC cell migration and metastasis. Via an activity-based protein profiling (ABPP) approach, a photoaffinity probe of RSV (RSV-P) was synthesized, and the protein targets of RSV in HeLa cells were identified. Based on target information and subsequent in vivo and in vitro validation experiments, we finally elucidated the mechanism of RSV corresponding to its antimetastatic activity.

KEY RESULTS

The results showed that RSV concentration-dependently suppressed CC cell migration and metastasis. A list of proteins was identified as the targets of RSV, through the ABPP approach with RSV-P, among which fatty acid binding protein 5 (FABP5) attracted our attention based on The Cancer Genome Atlas (TCGA) database analysis. Subsequent knockout and overexpression experiments confirmed that RSV directly interacted with FABP5 to inhibit fatty acid transport into the nucleus, thereby suppressing downstream matrix metalloproteinase-2 (MMP2) and matrix metalloproteinase-9 (MMP9) expression, thus inhibiting CC metastasis.

CONCLUSIONS AND IMPLICATIONS

Our study confirmed the key role of FABP5 in CC metastasis and provided important target information for the design of therapeutic lead compounds for metastatic CC.

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 and transcriptomic characterisation of FIA10, a novel murine leukemic cell line that metastasizes into the brain

Brain metastasis leads to increased mortality and is a major site of relapse for several cancers, yet the molecular mechanisms of brain metastasis are not well understood. In this study, we established and characterized a new leukemic cell line, FIA10, that metastasizes into the central nervous system (CNS) following injection into the tail vein of syngeneic mice. Mice injected with FIA10 cells developed neurological symptoms such as loss of balance, tremor, ataxic gait and seizures, leading to death within 3 months. Histopathology coupled with PCR analysis clearly showed infiltration of leukemic FIA10 cells into the brain parenchyma of diseased mice, with little involvement of bone marrow, peripheral blood and other organs. To define pathways that contribute to CNS metastasis, global transcriptome and proteome analysis was performed on FIA10 cells and compared with that of the parental stem cell line FDCP-Mix and the related FIA18 cells, which give rise to myeloid leukemia without CNS involvement. 188 expressed genes (RNA level) and 189 proteins were upregulated (log2 ratio FIA10/FIA18 ≥ 1) and 120 mRNAs and 177 proteins were downregulated (log2 ratio FIA10/FIA18 ≤ 1) in FIA10 cells compared with FIA18 cells. Major upregulated pathways in FIA10 cells revealed by biofunctional analyses involved immune response components, adhesion molecules and enzymes implicated in extracellular matrix remodeling, opening and crossing the blood-brain barrier (BBB), molecules supporting migration within the brain parenchyma, alterations in metabolism necessary for growth within the brain microenvironment, and regulators for these functions. Downregulated RNA and protein included several tumor suppressors and DNA repair enzymes. In line with the function of FIA10 cells to specifically infiltrate the brain, FIA10 cells have acquired a phenotype that permits crossing the BBB and adapting to the brain microenvironment thereby escaping immune surveillance. These data and our model system FIA10 will be valuable resources to study the occurrence of brain metastases and may help in the development of potential therapies against brain invasion.

Fatty-Acid-Binding Proteins: From Lipid Transporters to Disease Biomarkers

Fatty-acid-binding proteins (FABPs) serve a crucial role in the metabolism and transport of fatty acids and other hydrophobic ligands as an intracellular protein family. They are also recognized as a critical mediator in the inflammatory and ischemic pathways. FABPs are found in a wide range of tissues and organs, allowing them to contribute to various disease/injury developments that have not been widely discussed. We have collected and analyzed research journals that have investigated the role of FABPs in various diseases. Through this review, we discuss the findings on the potential of FABPs as biomarkers for various diseases in different tissues and organs, looking at their expression levels and their roles in related diseases according to available literature data. FABPs have been reported to show significantly increased expression levels in various tissues and organs associated with metabolic and inflammatory diseases. Therefore, FABPs are a promising novel biomarker that needs further development to optimize disease diagnosis and prognosis methods along with previously discovered markers.

FABP5 regulates lipid metabolism to facilitate pancreatic neuroendocrine neoplasms progression via FASN mediated Wnt/β-catenin pathway

Pancreatic neuroendocrine neoplasms (pNENs) are among the most frequently occurring neuroendocrine neoplasms (NENs) and require targeted therapy. High levels of fatty acid binding protein 5 (FABP5) are involved in tumor progression, but its role in pNENs remains unclear. We investigated the mRNA and protein levels of FABP5 in pNEN tissues and cell lines and found them to be upregulated. We evaluated changes in cell proliferation using CCK-8, colony formation, and 5-ethynyl-2'-deoxyuridine assays and examined the effects on cell migration and invasion using transwell assays. We found that knockdown of FABP5 suppressed the proliferation, migration, and invasion of pNEN cell lines, while overexpression of FABP5 had the opposite effect. Co-immunoprecipitation experiments were performed to clarify the interaction between FABP5 and fatty acid synthase (FASN). We further showed that FABP5 regulates the expression of FASN via the ubiquitin proteasome pathway and both proteins facilitate the progression of pNENs. Our study demonstrated that FABP5 acts as an oncogene by promoting lipid droplet deposition and activating the WNT/β-catenin signaling pathway. Moreover, the carcinogenic effects of FABP5 can be reversed by orlistat, providing a novel therapeutic intervention option.

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.

Aberrant DNA methylation-mediated NF-κB/fatty acid-binding protein 5 (FABP5) feed-forward loop promotes malignancy of colorectal cancer cells

Fatty acid-binding proteins (FABPs) are intracellular lipid-binding proteins that play roles in fatty acid transport and the regulation of gene expression. Dysregulated FABP expression and/or activity have been associated with cancer pathogenesis; in particular, epidermal-type FABP (FABP5) is upregulated in many types of cancer. However, the mechanisms regulating FABP5 expression and its involvement in cancer remain largely unknown. Here, we examined the regulation of FABP5 gene expression in non-metastatic and metastatic human colorectal cancer (CRC) cells. We found that FABP5 expression was upregulated in metastatic compared with non-metastatic CRC cells as well as in human CRC tissues compared with adjacent normal tissue. Analysis of the DNA methylation status of the FABP5 promoter showed that hypomethylation correlated with the malignant potential of the CRC cell lines. Moreover, FABP5 promoter hypomethylation also correlated with the expression pattern of splice variants of the DNA methyltransferase DNMT3B. ChIP assays and luciferase reporter assays demonstrated that the transcription factor nuclear factor-kappa B (NF-κB) was involved in regulating FABP5 expression. FABP5 expression could be upregulated in metastatic CRC cells by sequential promotion of DNA demethylation followed by activation of NF-κB. We also found that upregulated FABP5 in turn controlled NF-κB activity through IL-8 production. Collectively, these findings suggest the existence of a DNA methylation-dependent NF-κB /FABP5 positive feed-forward loop that may lead to constitutive activation of NF-κB signaling pathway and play a crucial role in CRC progression.

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.

Evolving Diagnostic and Treatment Strategies for Pediatric CNS Tumors: The Impact of Lipid Metabolism

Pediatric neurological tumors are a heterogeneous group of cancers, many of which carry a poor prognosis and lack a "standard of care" therapy. While they have similar anatomic locations, pediatric neurological tumors harbor specific molecular signatures that distinguish them from adult brain and other neurological cancers. Recent advances through the application of genetics and imaging tools have reshaped the molecular classification and treatment of pediatric neurological tumors, specifically considering the molecular alterations involved. A multidisciplinary effort is ongoing to develop new therapeutic strategies for these tumors, employing innovative and established approaches. Strikingly, there is increasing evidence that lipid metabolism is altered during the development of these types of tumors. Thus, in addition to targeted therapies focusing on classical oncogenes, new treatments are being developed based on a broad spectrum of strategies, ranging from vaccines to viral vectors, and melitherapy. This work reviews the current therapeutic landscape for pediatric brain tumors, considering new emerging treatments and ongoing clinical trials. In addition, the role of lipid metabolism in these neoplasms and its relevance for the development of novel therapies are discussed.

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.

Role of gene signature regulation in tumor immune microenvironment on the mechanism of uveal melanoma metastasis

BACKGROUND

Uveal melanoma (UM) is a rare but deadly cancer. The main cause of death from UM is liver metastasis. Though the metastasis mechanism remains unclear, it is closely related to the immune microenvironment and gene expression.

OBJECTIVE

This study aimed to identify the prognostic genes in primary and metastatic UM and their relationship with the immune microenvironment.

METHODS

Primary and metastatic UM data from the GEO database included GSE22138 and GSE44295 datasets. Kaplan-Meier analysis, Cox regression models, and ROC analysis were applied to screen genes in GSE22138. TIMER2.0 was employed to analyze the immune microenvironment from gene expression. Prognostic immune gene correlation was tested by Spearman. The results were validated in the independent dataset of cohort GSE44295.

RESULTS

Metastasis and primary differential gene analysis showed 107 significantly different genes associated with prognosis, and 11 of them were immune-related. ROC analysis demonstrated that our signature was predictive for UM prognosis (AUC > 0.8). Neutrophil and myeloid dendritic cells were closely associated with metastasis with scores that significantly divided patients into high-risk and low-risk groups (log-rank p< 0.05). Of these 11 genes, FABP5 and SHC4 were significantly associated with neutrophils in metastatic tumors, while ROBO1 expression was significantly correlated with myeloid dendritic cells in the primary tumors.

CONCLUSIONS

The present study constructed an 11-gene signature and established a model for risk stratification and prediction of overall survival in metastatic UM. Since FABP5 and SHC4 are related to neutrophil infiltration in metastatic UM, FABP5 and neutrophil regulation might be crucial in metastatic UM.

Identification of a pyroptosis-related prognosis gene signature and its relationship with an immune microenvironment in gliomas

BACKGROUND

Glioma is the most common type of primary brain cancer, and the prognosis of most patients with glioma is poor. Pyroptosis is a newly discovered inflammatory programmed cell death. However, the expression of pyroptosis-related genes (PRGs) in glioma and its correlation with prognosis are unclear.

METHODS

27 pyroptosis genes differentially expressed between glioma and adjacent normal tissues were identified. All glioma cases could be stratified into 2 subtypes based on these differentially expressed PRGs. The prognostic value of each PRG was evaluated to construct a prognostic model.

RESULTS

A novel 16-gene signature was constructed by using the least absolute shrinkage and selection operator Cox regression method. Then, patients with glioma were divided into low- and high-risk groups in the TCGA cohort. The survival rate of patients in the low-risk group was significantly higher than that in the high-risk group (P = .001). Patients with glioma from the Gene Expression Omnibus (GEO) cohort were stratified into 2 risk groups by using the median risk score. The overall survival (OS) of the low-risk group was longer than that of the high-risk group (P = .001). The risk score was considered an independent prognostic factor of the OS of patients with glioma. Gene ontology and Kyoto Encylopedia of Genes and Genomes analysis showed that the differentially expressed PRGs were mainly related to neutrophil activation involved in immune responses, focal adhesion, cell cycle, and p53 signaling pathway.

CONCLUSION

PRGs could predict the prognosis of glioma and play significant roles in a tumor immune microenvironment.

Cytoplasmic fatty acid-binding proteins in metabolic diseases and cancers

Cytoplasmic fatty acid-binding proteins (FABPs) are multipurpose proteins that can modulate lipid fluxes, trafficking, signaling, and metabolism. FABPs regulate metabolic and inflammatory pathways, its inhibition can improve type 2 diabetes mellitus and atherosclerosis. In addition, FABPs are involved in obesity, metabolic disease, cardiac dysfunction, and cancers. FABPs are promising tissue biomarkers in solid tumors for diagnostic and/or prognostic targets for novel therapeutic strategies. The signaling responsive elements of FABPs and determinants of FABP-mediated functions may be exploited in preventing or treating these diseases.

Fatty acid binding protein 5 regulates lipogenesis and tumor growth in lung adenocarcinoma

AIMS

Lung cancer is the leading cause of cancer-related death. Unfortunately, targeted-therapies have been unsuccessful for most patients with lung adenocarcinoma (LUAD). Thus, new early biomarkers and treatment options are a pressing need. Fatty acid binding protein 5 (FABP5) has been associated with various types of cancers. Its contribution to LUAD onset, progression and metabolic reprogramming is, however, not fully understood. In this study we assessed the importance of FABP5 in LUAD and its role in cancer lipid metabolism.

MAIN METHODS

By radioactive labeling and metabolite quantification, we studied the function of FABP5 in fatty acid metabolism using genetic/pharmacologic inhibition and overexpression models in LUAD cell lines. Flow cytometry, heterologous transplantation and bioinformatic analysis were used, in combination with other methodologies, to assess the importance of FABP5 for cellular proliferation in vitro and in vivo and in patient survival.

KEY FINDINGS

We show that high expression of FABP5 is associated with poor prognosis in patients with LUAD. FABP5 regulates lipid metabolism, diverting fatty acids towards complex lipid synthesis, whereas it does not affect their catabolism in vitro. Moreover, FABP5 is required for de novo fatty acid synthesis and regulates the expression of enzymes involved in the pathway (including FASN and SCD1). Consistently with the changes in lipid metabolism, FABP5 is required for cell cycle progression, migration and in vivo tumor growth.

SIGNIFICANCE

Our results suggest that FABP5 is a regulatory hub of lipid metabolism and tumor progression in LUAD, placing it as a new putative therapeutic target for this disease.

The Biological Functions and Regulatory Mechanisms of Fatty Acid Binding Protein 5 in Various Diseases

In recent years, fatty acid binding protein 5 (FABP5), also known as fatty acid transporter, has been widely researched with the help of modern genetic technology. Emerging evidence suggests its critical role in regulating lipid transport, homeostasis, and metabolism. Its involvement in the pathogenesis of various diseases such as metabolic syndrome, skin diseases, cancer, and neurological diseases is the key to understanding the true nature of the protein. This makes FABP5 be a promising component for numerous clinical applications. This review has summarized the most recent advances in the research of FABP5 in modulating cellular processes, providing an in-depth analysis of the protein's biological properties, biological functions, and mechanisms involved in various diseases. In addition, we have discussed the possibility of using FABP5 as a new diagnostic biomarker and therapeutic target for human diseases, shedding light on challenges facing future research.

Regulatory mechanisms of Beta-carotene and BCMO1 in adipose tissues: A gene enrichment-based bioinformatics analysis

Beta-carotene (β-carotene, BC) is one of the carotenoids most commonly consumed by humans. BCMO1 is expressed in various human tissues and is considered to be a key enzyme that converts BC into vitamin A. Studies indicated that BC-derived carotenoid signaling molecules affected the physiological functions of fat cells. In order to investigate the role and possible molecular mechanism of BC in mouse adipocytes, we conducted 4-group and 2-group difference analysis based on the data of GSE27271 chip in the Gene Expression Omnibus database. Genes differentially expressed in the inguinal white adipose tissue of mice were screened out and combined with the STRING database to construct protein-protein interaction (PPI) networks. Among them, Alb (albumin), Mug1 (murinoglobulin-1) and Uox (urate oxidase) genes were at relatively key positions and may affect the action of BC. Besides, Ppara (peroxisome proliferator-activated receptor alpha), Acly (ATP-citrate lyase) and Fabp5 (fatty acid-binding protein 5) genes constituted functional partners with many genes in the PPI network, and these genes may be Bcmo1 targeting molecules. Gene Ontology (GO) function and signaling pathways enrichment analysis were performed on the genes with protein interaction relationship in the PPI network. Fatty acid binding, cholesterol metabolic process, and regulation of fatty acid metabolic process were significantly enriched, and PPAR signaling pathway showed the most significant, indicating that BC and Bcmo1 might synergistically affect body metabolic functions such as fat metabolism. In general, BC and Bcmo1 may play a role in fat metabolism in mice, thereby affecting other functions or diseases.

Tumor-intrinsic FABP5 is a novel driver for colon cancer cell growth via the HIF-1 signaling pathway

Dysfunctional lipid metabolism is a known cause of cancer development and progression, yet little is known about the underlying molecular mechanisms that contribute to cancer progression. In this study, we demonstrate that fatty acid binding protein 5 (FABP5) is elevated in colon cancer tissue and this increased expression is linked to upregulation of the hypoxia-inducible factor-1 (HIF-1) signaling pathway. Under physiologically in vivo mimicked conditions via a polydimethylsiloxane (PDMS)-based three-dimensional (3D) culture chip, FABP5-knockdown colon cancer cells exhibited attenuated cell growth throughout the culture period. FABP5 was found to regulate HIF-1α protein levels and gene expression levels within the HIF-1α signaling pathway under hypoxic conditions. Our results provide evidence that supports the use of FABP5 as a prognostic factor in colon cancer. The FABP5/HIF-1α axis is a promising target for ameliorating fatty acid-triggered cancer progression.

Expression and function analysis of CRABP2 and FABP5, and their ratio in esophageal squamous cell carcinoma

Objective

The purpose of this study was to explore the effect of CRABP2 and FABP5, and their ratio on prognosis in esophageal squamous cell carcinoma.

Methods

The expression data of CRABP2 in esophageal cancer in TCGA and GEO were collected by the public database GEPIA. The expression levels of CRABP2 and FABP5 were examined using immunohistochemistry. The relationship between the two proteins and related clinicopathological parameters were analyzed by χ² test. Survival analysis was used to investigate the effect of CRABP2 and FABP5, and their ratio on prognosis.

Results

Compared with normal esophageal mucosal epithelium, there was lower CRABP2 gene mRNA in the esophageal cancer tissue, and the difference was statistically significant (p < 0.01). For the expression level, no significant difference was observed in patients with stages I–IV in esophageal cancer. Immunohistochemistry showed that CRABP2 and FABP5 were both highly expressed in normal esophageal squamous epithelial cells at 100 and 94.1%, while lower in ESCC (75.6 and 58.7%). There was a significant difference in the expression between cancer and adjacent tissues (p < 0.001). No inherent relationship was manifested between the CRABP2 expression and the clinical parameters of the ESCC. The expression of FABP5 was related to lymph node metastasis (p = 0.032), the depth of invasion (p = 0.041), and the AJCC stage (p = 0.013). The ratio of CRABP2 and FABP5 was related to ethnicity (p = 0.001), nerve invasion (p = 0.031), and postoperative treatment (p = 0.038). CRABP2 is positively associated with FABP5 (r = 0.156, p = 0.041) and the ratio (r = 0.334, p = 0.000), while there was a negative correlation between FABP5 and the ratio (r = −0.269, p = 0.000). Patients with CRABP2-positive expression had a significantly longer overall survival than patients with CRABP2-negative expression (p = 0.025).

Conclusion

CRABP2 as a suppressor factor is expected to be a potential prognosis marker for esophageal squamous cell carcinoma.

Fatty acids and evolving roles of their proteins in neurological, cardiovascular disorders and cancers

The dysregulation of fat metabolism is involved in various disorders, including neurodegenerative, cardiovascular, and cancers. The uptake of long-chain fatty acids (LCFAs) with 14 or more carbons plays a pivotal role in cellular metabolic homeostasis. Therefore, the uptake and metabolism of LCFAs must constantly be in tune with the cellular, metabolic, and structural requirements of cells. Many metabolic diseases are thought to be driven by the abnormal flow of fatty acids either from the dietary origin and/or released from adipose stores. Cellular uptake and intracellular trafficking of fatty acids are facilitated ubiquitously with unique combinations of fatty acid transport proteins and cytoplasmic fatty acid-binding proteins in every tissue. Extensive data are emerging on the defective transporters and metabolism of LCFAs and their clinical implications. Uptake and metabolism of LCFAs are crucial for the brain's functional development and cardiovascular health and maintenance. In addition, data suggest fatty acid metabolic transporter can normalize activated inflammatory response by reprogramming lipid metabolism in cancers. Here we review the current understanding of how LCFAs and their proteins contribute to the pathophysiology of three crucial diseases and the mechanisms involved in the processes.

Fatty acid oxidation: driver of lymph node metastasis

Fatty acid oxidation (FAO) is the emerging hallmark of cancer metabolism because certain tumor cells preferentially utilize fatty acids for energy. Lymph node metastasis, the most common way of tumor metastasis, is much indispensable for grasping tumor progression, formulating therapy measure and evaluating tumor prognosis. There is a plethora of studies showing different ways how tumor cells metastasize to the lymph nodes, but the role of FAO in lymph node metastasis remains largely unknown. Here, we summarize recent findings and update the current understanding that FAO may enable lymph node metastasis formation. Afterward, it will open innovative possibilities to present a distinct therapy of targeting FAO, the metabolic rewiring of cancer to terminal cancer patients.

Downregulation of FABP5 Suppresses the Proliferation and Induces the Apoptosis of Gastric Cancer Cells Through the Hippo Signaling Pathway

Fatty acid binding protein 5 (FABP5) has been reported to play an important role in various cancers. We found that high FABP5 expression was associated with poor histological differentiation and vascular invasion. High FABP5 expression indicated a poor prognosis. Downregulation of FABP5 suppressed cell proliferation, cell migration and invasion, and induced cell apoptosis. Bioinformatic analysis revealed that the Hippo signaling pathway was related to FABP5. We found that overexpression of yes-associated protein 1 (YAP1) could partially reverse the effect of FABP5 knockdown on growth and apoptosis. The FABP5 inhibitor SBFI-26 suppressed the proliferation and promoted the apoptosis of gastric cancer (GC) cells and interfered with the Hippo signaling pathway by inhibiting YAP1. Our data suggested that FABP5 might act as a potential target associated with the Hippo signaling pathway for GC treatment.

Fatty acid-binding protein 5 controls lung tumor metastasis by regulating the maturation of natural killer cells in the lung

Fatty acid-binding protein (FABP) 5 is highly expressed in various types of tumors and is strongly correlated with tumor growth, development, and metastasis. However, it is unclear how the expression of FABP5 in the host affects tumor progression. In this study, using a lung tumor metastasis model in mice, we found that FABP5-deficient mice were more susceptible to tumor metastasis, which is accompanied by infiltration of a lower frequency of activated natural killer (NK) cells in the lung. Additionally, FABP5 deficiency leads to impaired maturation of NK cells in the lungs, but not in the bone marrow and spleen. Taken together, our results provide the first evidence that FABP5 in the host regulates lung tumor metastasis through controlling NK cell maturation.

The metabolism of cancer cells during metastasis

Metastasis formation is the major cause of death in most patients with cancer. Despite extensive research, targeting metastatic seeding and colonization is still an unresolved challenge. Only recently, attention has been drawn to the fact that metastasizing cancer cells selectively and dynamically adapt their metabolism at every step during the metastatic cascade. Moreover, many metastases display different metabolic traits compared with the tumours from which they originate, enabling survival and growth in the new environment. Consequently, the stage-dependent metabolic traits may provide therapeutic windows for preventing or reducing metastasis, and targeting the new metabolic traits arising in established metastases may allow their eradication.

Therapeutic potential of cannabinoids in combination cancer therapy

Derivatives of the plant Cannabis sativa have been used for centuries for both medical and recreational purposes, as well as industrial. The first proof of its medicinal use comes from ancient China, although there is evidence of its earlier utilization in Europe and Asia. In the 19th century, European practitioners started to employ cannabis extracts to treat tetanus, convulsions, and mental diseases and, in 1851, cannabis made its appearance in the Pharmacopoeia of the United States as an analgesic, hypnotic and anticonvulsant. It was only in 1937 that the Marijuana Tax Act prohibited the use of this drug in the USA. The general term Cannabis is commonly used by the scientific and scholar community to indicate derivatives of the plant Cannabis sativa. The word cannabinoid is a term describing chemical compounds that are either derivate of Cannabis (phytocannabinoids) or artificial analogues (synthetic) or are produced endogenously by the body (endocannabinoids). A more casual term "marijuana" or "weed", a compound derived from dried Cannabis flower tops and leaves, has progressively superseded the term cannabis when referred to its recreational use. The 2018 World health organisation (WHO) data suggest that nearly 2.5% of the global population (147 million) uses marijuana and some countries, such as Canada and Uruguay, have already legalised it. Due to its controversial history, the medicinal use of cannabinoids has always been a centre of debate. The isolation and characterisation of Δ⁹ tetrahydrocannabinol (THC), the major psychoactive component of cannabis and the detection of two human cannabinoid receptor (CBRs) molecules renewed interest in the medical use of cannabinoids, boosting research and commercial heed in this sector. Some cannabinoid-based drugs have been approved as medications, mainly as antiemetic, antianorexic, anti-seizure remedies and in cancer and multiple sclerosis patients' palliative care. Nevertheless, due to the stigma commonly associated with these compounds, cannabinoids' potential in the treatment of conditions such as cancer is still largely unknown and therefore underestimated.

Different Immunohistochemical Localization of Fatty Acid Binding Protein 5 in Actinic Keratosis Compared with That in Bowen's Disease: A Retrospective Study

ABSTRACT

Actinic keratosis (AK) and Bowen's disease (BD) are common premalignant lesions of invasive squamous cell carcinoma that have different pathogenesis and clinical significance. Fatty acid-binding protein 5 (FABP5) is responsible for keratinocyte homeostasis and differentiation; however, no study has revealed its expression in AK and BD. Our study aimed to investigate the differential expression and significance of FABP5 in these lesions. Patients with pathologically confirmed cases of AK (n = 37) and BD (n = 12) were included in this study. FABP5 immunostaining pattern was assessed in the normal skin, AK and BD lesions, with a focus on the staining patterns of basal cells, atypical keratinocytes, and uninvolved epidermal keratinocytes. All patients with AK showed negative FABP5 expression in the atypical cells in the basal layer, whereas the uninvolved upper layers showed diffuse, strong FABP5 expression, regardless of the grade of AK. All patients with BD showed heterogeneous and diffuse FABP5 expression in atypical cells of all layers of the epidermis. This study is the first to investigate the role of FABP5 in premalignant skin lesions. The unique immunohistochemical localization of the FABP5 can be a helpful diagnostic marker, and altered fatty acid metabolism may be the key in understanding the different pathophysiology of AK and BD.

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

Hypoxia-inducible factor-1 alpha (HIF-1α) is a transcription factor essential for cancer cell survival. The reprogramming of lipid metabolism has emerged as a hallmark of cancer, yet the relevance of HIF-1α to this process remains elusive. In this study, we profile HIF-1α-interacting proteins using proteomics analysis and identify fatty acid-binding protein 5 (FABP5) as a critical HIF-1α-binding partner. In hepatocellular carcinoma (HCC) tissues, both FABP5 and HIF-1α are upregulated, and their expression levels are associated with poor prognosis. FABP5 enhances HIF-1α activity by promoting HIF-1α synthesis while disrupting FIH/HIF-1α interaction at the same time. Oleic-acid treatment activates the FABP5/HIF-1α axis, thereby promoting lipid accumulation and cell proliferation in HCC cells. Our results indicate that fatty-acid-induced FABP5 upregulation drives HCC progression through HIF-1-driven lipid metabolism reprogramming.

Seo et al. identify fatty acid-binding protein 5 (FABP5) as a booster of HIF-1α activity. They find that oleic-acid treatment activates the FABP5/HIF-1α axis, promoting lipid accumulation and cell proliferation in liver cancer cells. This study provides insights into how fatty acids drive the progression of cancer.

Anti-Cancer Potential of Cannabinoids, Terpenes, and Flavonoids Present in Cannabis

In recent years, and even more since its legalization in several jurisdictions, cannabis and the endocannabinoid system have received an increasing amount of interest related to their potential exploitation in clinical settings. Cannabinoids have been suggested and shown to be effective in the treatment of various conditions. In cancer, the endocannabinoid system is altered in numerous types of tumours and can relate to cancer prognosis and disease outcome. Additionally, cannabinoids display anticancer effects in several models by suppressing the proliferation, migration and/or invasion of cancer cells, as well as tumour angiogenesis. However, the therapeutic use of cannabinoids is currently limited to the treatment of symptoms and pain associated with chemotherapy, while their potential use as cytotoxic drugs in chemotherapy still requires validation in patients. Along with cannabinoids, cannabis contains several other compounds that have also been shown to exert anti-tumorigenic actions. The potential anti-cancer effects of cannabinoids, terpenes and flavonoids, present in cannabis, are explored in this literature review.

OSlgg: An Online Prognostic Biomarker Analysis Tool for Low-Grade Glioma

Glioma is the most frequent primary brain tumor that causes high mortality and morbidity with poor prognosis. There are four grades of gliomas, I to IV, among which grade II and III are low-grade glioma (LGG). Although less aggressive, LGG almost universally progresses to high-grade glioma and eventual causes death if lacking of intervention. Current LGG treatment mainly depends on surgical resection followed by radiotherapy and chemotherapy, but the survival rates of LGG patients are low. Therefore, it is necessary to use prognostic biomarkers to classify patients into subgroups with different risks and guide clinical managements. Using gene expression profiling and long-term follow-up data, we established an Online consensus Survival analysis tool for LGG named OSlgg. OSlgg is comprised of 720 LGG cases from two independent cohorts. To evaluate the prognostic potency of genes, OSlgg employs the Kaplan-Meier plot with hazard ratio and p value to assess the prognostic significance of genes of interest. The reliability of OSlgg was verified by analyzing 86 previously published prognostic biomarkers of LGG. Using OSlgg, we discovered two novel potential prognostic biomarkers (CD302 and FABP5) of LGG, and patients with the elevated expression of either CD302 or FABP5 present the unfavorable survival outcome. These two genes may be novel risk predictors for LGG patients after further validation. OSlgg is public and free to the users at http://bioinfo.henu.edu.cn/LGG/LGGList.jsp.

Identification of prognostic gene biomarkers for metastatic skin cancer using data mining

Skin cancer is a common malignant tumor in China and throughout the world, and the rate of recurrence is considerably high, thus endangering the quality of life and health of patients, and increasing the economic burden and pressure to the families of those afflicted. Due to the limitations of traditional drug treatments, it is difficult to achieve the desired therapeutic effect of complete removal. However, targeted gene therapy may be a novel means of treating skin cancer, as the targeted nature of treatment may improve therapeutic outcomes. However, targeted gene therapy requires physicians to select the appropriate gene, which means suitable genetic biomarkers must be identified from complex genetic data. In the present study, the least absolute shrinkage and selection operator regression analysis method was used with 10-fold cross verification to reduce the dimensions of gene data in patients with skin cancer, and subsequently, 20 gene biomarkers were screened. A prognostic model was constructed using these 20 gene biomarkers, and the validity of the model was assessed using a training set and a verification set, which showed that the model performed well. Finally, gene function analysis of these 20 gene biomarkers was determined. Relevant studies were found to show that the genetic biomarkers identified in this paper may possess value for the follow-up clinical treatment of skin cancer.

FABP5 promotes lymph node metastasis in cervical cancer by reprogramming fatty acid metabolism

Patients with cervical cancer (CCa) with lymph node metastasis (LNM) have an extremely poor prognosis. Elucidation of the molecular mechanisms underlying LNM may provide clinical therapeutic strategies for CCa. Upregulation of fatty acid-binding protein 5 (FABP5) expression in CCa tumours was demonstrated to positively correlate with LNM. However, the precise role and mechanisms of FABP5 in the LNM of CCa remain unknown. Methods: The diagnostic value of FABP5 as a predictor of LNM in CCa was evaluated in CCa tumour samples. The functional role of FABP5 and its upstream and downstream regulatory factors were investigated by gain-of-function and loss-of-function assays in vitro and in vivo. A mouse model of LNM was used to determine the effect of FABP5 on LNM and the therapeutic value of FABP5 targeting. Results: We demonstrated that FABP5 was markedly upregulated in CCa with LNM and correlated with poor prognosis. FABP5 protein was an independent predictor of LNM in a multivariate logistic analysis. Furthermore, FABP5 promoted epithelial-mesenchymal transition, lymphangiogenesis, and LNM by reprogramming fatty acid (FA) metabolism. Mechanistically, FABP5 promoted lipolysis and FA synthesis, which led to an increase in intracellular fatty acids (FAs) that activated NF-κB signalling, thus inducing LNM. Importantly, administration of orlistat, which attenuates FA metabolism reprogramming, inhibited FABP5-induced LNM in CCa. The pro-metastatic effect of FABP5 was reduced by miR-144-3p. Moreover, miR-144-3p was significantly downregulated and FABP5 was upregulated in CCa in a hypoxic microenvironment. Conclusion: Our findings highlight a FA metabolism-dependent mechanism of FABP5-induced LNM. Moreover, the expression and biological function of FABP5 can be regulated by miR-144-3p in hypoxia. Our study identifies FABP5 as a potential diagnostic biomarker and therapeutic target for LNM in CCa.

Fatty acid-binding protein 5 predicts poor prognosis in patients with uveal melanoma

Fatty acid-binding protein 5 (FABP5), which participates in mediating the biological properties of tumor cells, has been recognized in several neoplasms. The present study aims to investigate FABP5 transcriptional expression profiles, reveal its underlying biological interaction networks and define its prognostic value in uveal melanoma (UVM). A total of 80 patients with UVM and their RNA-sequence data, available from The Cancer Genome Atlas (TCGA) database, was analyzed. A differential transcriptional expression profile was obtained from TCGA and the Oncomine databases. The survival benefits were analyzed using the Kaplan-Meier method and log-rank test. The correlation between FABP5 expression and immune infiltration level was analyzed using the Tumor Immune Estimation Resource database. Functional enrichment analyses using Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and signaling hallmarks were utilized to describe the biological process, molecular functions, cellular component and significantly involved pathways. The elevated transcriptional expression of FABP5 was significantly associated with shorter overall survival (OS) and worse progression-free survival (PFS) times in patients with UVM (P<0.001). Moreover, FABP5 expression was significantly and positively correlated with tumor purity and CD8⁺ T cells and was negatively correlated with the infiltrating levels of CD4⁺ T cells and neutrophils. Gene Set Enrichment Analysis was performed to obtain 100 significantly associated genes of FABP5 and FABP5 was found to be critical in several hallmark pathways, including allograft rejection, complement, interleukin-6/Janus kinase-STAT3 signaling, interferon γ response, inflammatory response and tumor necrosis factor α signaling via NFκB. The present study is the first to demonstrate that FABP5 expression was positively associated with progression-associated clinicopathological factors and poor prognosis in UVM, which suggests its likely function as an oncogene and prognostic marker in patients with UVM.

Distinct signatures of lung cancer types: aberrant mucin O-glycosylation and compromised immune response

BACKGROUND

Genomic initiatives such as The Cancer Genome Atlas (TCGA) contain data from -omics profiling of thousands of tumor samples, which may be used to decipher cancer signaling, and related alterations. Managing and analyzing data from large-scale projects, such as TCGA, is a demanding task. It is difficult to dissect the high complexity hidden in genomic data and to account for inter-tumor heterogeneity adequately.

METHODS

In this study, we used a robust statistical framework along with the integration of diverse bioinformatic tools to analyze next-generation sequencing data from more than 1000 patients from two different lung cancer subtypes, i.e., the lung adenocarcinoma (LUAD) and the squamous cell carcinoma (LUSC).

RESULTS

We used the gene expression data to identify co-expression modules and differentially expressed genes to discriminate between LUAD and LUSC. We identified a group of genes which could act as specific oncogenes or tumor suppressor genes in one of the two lung cancer types, along with two dual role genes. Our results have been validated against other transcriptomics data of lung cancer patients.

CONCLUSIONS

Our integrative approach allowed us to identify two key features: a substantial up-regulation of genes involved in O-glycosylation of mucins in LUAD, and a compromised immune response in LUSC. The immune-profile associated with LUSC might be linked to the activation of three oncogenic pathways, which promote the evasion of the antitumor immune response. Collectively, our results provide new future directions for the design of target therapies in lung cancer.

Modulation of the Endocannabinoid System as a Potential Anticancer Strategy

Currently, the involvement of the endocannabinoid system in cancer development and possible options for a cancer-regressive effect of cannabinoids are controversially discussed. In recent decades, a number of preclinical studies have shown that cannabinoids have an anticarcinogenic potential. Therefore, especially against the background of several legal simplifications with regard to the clinical application of cannabinoid-based drugs, an extended basic knowledge about the complex network of the individual components of the endocannabinoid system is required. The canonical endocannabinoid system consists of the endocannabinoids N-arachidonoylethanolamine (anandamide) and 2-arachidonoylglycerol as well as the G_i/o protein-coupled transmembrane cannabinoid receptors CB₁ and CB₂. As a result of extensive studies on the broader effect of these factors, other fatty acid derivatives, transmembrane and intracellular receptors, enzymes and lipid transporters have been identified that contribute to the effect of endocannabinoids when defined in the broad sense as “extended endocannabinoid system.” Among these additional components, the endocannabinoid-degrading enzymes fatty acid amide hydrolase and monoacylglycerol lipase, lipid transport proteins of the fatty acid-binding protein family, additional cannabinoid-activated G protein-coupled receptors such as GPR55, members of the transient receptor family, and peroxisome proliferator-activated receptors were identified as targets for possible strategies to combat cancer progression. Other endocannabinoid-related fatty acids such as 2-arachidonoyl glyceryl ether, O-arachidonoylethanolamine, N-arachidonoyldopamine and oleic acid amide showed an effect via cannabinoid receptors, while other compounds such as endocannabinoid-like substances exert a permissive action on endocannabinoid effects and act via alternative intracellular target structures. This review gives an overview of the modulation of the extended endocannabinoid system using the example of anticancer cannabinoid effects, which have been described in detail in preclinical studies.

FABP5 regulates the proliferation of clear cell renal cell carcinoma cells via the PI3K/AKT signaling pathway

Clear cell renal cell carcinoma (ccRCC) has been associated with one of the highest mortality rates among all cancers. Fatty acid binding proteins (FABPs) are 14‑15 kDa proteins that are highly abundant in the cytosol of most tissues. FABP5, a member of the FABP family, has been observed to promote tumor cell growth in numerous cancer types. In order to investigate the function of FABP5 in ccRCC cells in the present study, RNA sequencing data from The Cancer Genome Atlas were analyzed to determine the expression levels of FABP5 in ccRCC patient samples. Survival and Cox regression analyses were performed to measure the association between FABP5 expression and clinicopathological features of patients with ccRCC. Subsequent in vitro experiments downregulated or overexpressed FABP5 in Caki‑1 and 786O ccRCC cells using lentiviral vectors to evaluate cell proliferation ability, and a xenograft transplantation model was established to examine the effect of FABP5 on tumorigenesis in vivo. The results demonstrated that FABP5 expression was significantly upregulated in samples from patients with ccRCC when compared with normal tissue samples. High FABP5 expression was also significantly correlated with tumor and metastasis classifications and predicted poor survival in patients with ccRCC. In ccRCC cells, silencing of FABP5 significantly inhibited cell proliferation, while overexpression of FABP5 promoted cell proliferation when compared to the respective controls. In addition, treatment with the phosphatidylinositol‑4,5‑bisphosphate 3‑kinase (PI3K)/AKT inhibitor, LY294002, attenuated the pro‑proliferative effects of exogenous FABP5 expression in Caki‑1 and 786O cells. This indicated that the PI3K/AKT signaling pathway may be partially involved in the FABP5‑mediated increase in ccRCC cell proliferation. Furthermore, FABP5 was observed to regulate tumor growth in nude mice in vivo. In conclusion, the results of the present study suggest that FABP5 may exert a pro‑proliferative role in ccRCC and may be associated with malignant progression and tumorigenesis.

Altered epidermal fatty acid-binding protein expression in hepatocellular carcinoma predicts unfavorable outcomes

Objective

Hepatocellular carcinoma (HCC) is a rapidly proliferating malignancy that requires large amounts of fatty acids to synthesize cellular membranes and provide energy. Epidermal fatty acid-binding protein (EFABP) is uniquely expressed in epidermal cells, but its role and expression in HCC are not clear.

Subjects and methods

A total of 804 HCC specimens were collected to construct a tissue microarray (TMA) and for immunohistochemistry (IHC) analysis. The relationship between EFABP expression and clinical features of patients with HCC was analyzed.

Results

The EFABP IHC score for HCC tissue was 0.76±0.69, being significantly higher than that for matched nontumorous tissue (0.48±0.55; P<0.001). Using the median IHC score (ie, 0.8) in the tumorous tissue, a high level of EFABP expression was found in 57.3% (461/804) of the cases. Patients with HCC displaying high EFABP expression had poorer tumor differentiation (P=0.029), more vascular invasion (P=0.006), and a higher proportion of late TNM stage disease (P=0.042). Kaplan-Meier analysis revealed that the patients with high EFABP expression had significantly worse outcomes in terms of overall survival (P=0.003), worse disease-free survival (P=0.021), and a higher probability of recurrence (P=0.014). Multivariate analysis indicated that EFABP expression was an independent prognostic variable for overall survival (P=0.021) and disease-free survival (P=0.044). For HCC recurrence, only vascular invasion (P=0.020) and EFABP expression (P=0.026) were independent risk factors.

Conclusion

Our data revealed that EFABP expression was increased in HCC samples. High EFABP expression was correlated with shorter survival times in patients with HCC and served as an independent factor for worse outcomes. Our study therefore provides a promising bio-marker for the prognostic prediction of HCC and a potential therapeutic target for the disease.

Proteomic profiling of liver tissue from the mdx-4cv mouse model of Duchenne muscular dystrophy

Background

Duchenne muscular dystrophy is a highly complex multi-system disease caused by primary abnormalities in the membrane cytoskeletal protein dystrophin. Besides progressive skeletal muscle degeneration, this neuromuscular disorder is also associated with pathophysiological perturbations in many other organs including the liver. To determine potential proteome-wide alterations in liver tissue, we have used a comparative and mass spectrometry-based approach to study the dystrophic mdx-4cv mouse model of dystrophinopathy.

Methods

The comparative proteomic profiling of mdx-4cv versus wild type liver extracts was carried out with an Orbitrap Fusion Tribrid mass spectrometer. The distribution of identified liver proteins within protein families and potential protein interaction patterns were analysed by systems bioinformatics. Key findings on fatty acid binding proteins were confirmed by immunoblot analysis and immunofluorescence microscopy.

Results

The proteomic analysis revealed changes in a variety of protein families, affecting especially fatty acid, carbohydrate and amino acid metabolism, biotransformation, the cellular stress response and ion handling in the mdx-4cv liver. Drastically increased protein species were identified as fatty acid binding protein FABP5, ferritin and calumenin. Decreased liver proteins included phosphoglycerate kinase, apolipoprotein and perilipin. The drastic change in FABP5 was independently verified by immunoblotting and immunofluorescence microscopy.

Conclusions

The proteomic results presented here indicate that the intricate and multifaceted pathogenesis of the mdx-4cv model of dystrophinopathy is associated with secondary alterations in the liver affecting especially fatty acid transportation. Since FABP5 levels were also shown to be elevated in serum from dystrophic mice, this protein might be a useful indicator for monitoring liver changes in X-linked muscular dystrophy.

Expression of tissue factor in human cervical carcinoma tissue

The present study aimed to investigate tissue factor (TF) expression in cervical cancer and explore its association with disease progression. A total of 258 cervical cancer tissues and their adjacent normal tissues were collected between September 2014 and September 2016. TF expression was detected in the tissue samples by immunohistochemistry and western blot analysis. Associations between the expression of TF and clinical stage, differentiation status and metastasis of cancer cells were examined. The mean immunohistochemistry score of TF expression in cervical cancer tissues was 2.86±1.76, which was significantly increased compared with the adjacent normal tissues (0.28±0.45). The expression of TF was also significantly associated with the clinical stage, lymph node metastasis and distant metastasis of cancer cells. Immunohistochemistry staining and western blot analysis demonstrated that TF expression in cervical cancer tissues significantly increased as the clinical stage increased. TF expression in tumor tissues from patients with lymph node metastasis was significantly increased compared with samples from patients without lymph node metastasis. TF expression was also significantly increased in patients with distant metastasis compared with those without. In conclusion, TF is highly expressed in cervical cancer tissues and high expression of TF may enhance the invasion and metastasis of cervical cancer cells.

Differentially expressed proteins in positive versus negative HNSCC lymph nodes

Background

Lymph node metastasis is one of the most important prognostic factors in head and neck squamous cell carcinomas (HNSCCs) and critical for delineating their treatment. However, clinical and histological criteria for the diagnosis of nodal status remain limited. In the present study, we aimed to characterize the proteomic profile of lymph node metastasis from HNSCC patients.

Methods

In the present study, we used one- and two-dimensional electrophoresis and mass spectrometry analysis to characterize the proteomic profile of lymph node metastasis from HNSCC.

Results

Comparison of metastatic and non-metastatic lymph nodes showed 52 differentially expressed proteins associated with neoplastic development and progression. The results reinforced the idea that tumors from different anatomical subsites have dissimilar behaviors, which may be influenced by micro-environmental factor including the lymphatic network. The expression pattern of heat shock proteins and glycolytic enzymes also suggested an effect of the lymph node environment in controlling tumor growth or in metabolic reprogramming of the metastatic cell. Our study, for the first time, provided direct evidence of annexin A1 overexpression in lymph node metastasis of head and neck cancer, adding information that may be useful for diagnosing aggressive disease.

Conclusions

In brief, this study contributed to our understanding of the metastatic phenotype of HNSCC and provided potential targets for diagnostic in this group of carcinomas.

Electronic supplementary material

The online version of this article (10.1186/s12920-018-0382-6) contains supplementary material, which is available to authorized users.

4-Amino-2-trifluoromethyl-phenyl retinate inhibits proliferation, invasion, and migration of breast cancer cells by independently regulating CRABP2 and FABP5

BACKGROUND

4-Amino-2-trifluoromethyl-phenyl retinate (ATPR), a novel retinoid derivative, inhibits proliferation and induces differentiation in many cancer cells. In this study, the inhibitory effects of ATPR on the proliferation, invasion, and migration of breast cancer (BC) cells, and the relationship between ATPR and the expression of the intracellular lipid-binding proteins CRABP2 and FABP5 were investigated.

METHODS

CRABP2 and FABP5 expression was evaluated in infiltrating breast-infiltrating ductal carcinoma(BIDC) and benign breast fibroma (BBF) by immunohistochemistry and in MCF-7, MDA-MB-231, MDA-MB-435, and MDA-MB-453 cells by immunofluorescence. The inhibition of proliferation by ATPR in these cells was detected by MTT. After downregulation and upregulation of CRABP2 and FABP5 in MCF-7 or MDA-MB-231 cells using siRNA and plasmids, the effect of ATPR on proliferation was detected by MTT and real-time cell analysis, and the effects of ATPR on the invasion and migration of MDA-MB-231 cells were detected using a Boyden chamber assay and a wound healing assay.

RESULTS

CRABP2 expression was moderately or strongly positive in BIDC and BBF. FABP5 expression was also moderately or strongly positive in BIDC, but weakly positive or negative in BBF. CRABP2 and FABP5 were highly expressed in MCF-7 cells, moderately expressed in MDA-MB-453 cells, and weakly expressed in MDA-MB-435 and MDA-MB-231 cells. ATPR inhibited proliferation more strongly in MCF-7 cells than in other cells. The inhibition of proliferation by ATPR depended on an increase in CRABP2, but not FABP5 expression. A decrease in FABP5 could inhibit the invasion and migration of BC cells.

CONCLUSION

These findings indicate that ATPR might inhibit proliferation by upregulating CRABP2, and inhibit invasion and migration by downregulating FABP5 in BC cells. These findings may facilitate the use of differentiation therapy in BC.

The peritumoural adipose tissue microenvironment and cancer. The roles of fatty acid binding protein 4 and fatty acid binding protein 5

The adipose tissue microenvironment plays a key role in tumour initiation and progression because it provides fatty acids and adipokines to tumour cells. The fatty acid-binding protein (FABP) family is a group of small proteins that act as intracellular fatty acid transporters. Adipose-derived FABPs include FABP4 and FABP5. Both have an important role in lipid-related metabolic processes and overexpressed in many cancers, such as breast, prostate, colorectal and ovarian. Moreover, their expression in peritumoural adipose tissue is deregulated, and their circulating levels are upregulated in some tumours. In this review, we discuss the role of the peritumoural adipose tissue and the related adipokines FABP4 and FABP5 in cancer initiation and progression and the possible pathways implicated in these processes.

Targeting the endocannabinoid system as a potential anticancer approach

The endocannabinoid system is currently under intense investigation due to the therapeutic potential of cannabinoid-based drugs as treatment options for a broad variety of diseases including cancer. Besides the canonical endocannabinoid system that includes the cannabinoid receptors CB₁ and CB₂ and the endocannabinoids N-arachidonoylethanolamine (anandamide) and 2-arachidonoylglycerol, recent investigations suggest that other fatty acid derivatives, receptors, enzymes, and lipid transporters likewise orchestrate this system as components of the endocannabinoid system when defined as an extended signaling network. As such, fatty acids acting at cannabinoid receptors (e.g. 2-arachidonoyl glyceryl ether [noladin ether], N-arachidonoyldopamine) as well as endocannabinoid-like substances that do not elicit cannabinoid receptor activation (e.g. N-palmitoylethanolamine, N-oleoylethanolamine) have raised interest as anticancerogenic substances. Furthermore, the endocannabinoid-degrading enzymes fatty acid amide hydrolase and monoacylglycerol lipase, lipid transport proteins of the fatty acid binding protein family, additional cannabinoid-activated G protein-coupled receptors, members of the transient receptor potential family as well as peroxisome proliferator-activated receptors have been considered as targets of antitumoral cannabinoid activity. Therefore, this review focused on the antitumorigenic effects induced upon modulation of this extended endocannabinoid network.

PBX3 is associated with proliferation and poor prognosis in patients with cervical cancer

Pre-B-cell leukemia homeobox 3 (PBX3) is upregulated in various malignancies; however, the role of PBX3 in cervical cancer (CC) is unknown. The purpose of this study was to explore the expression characteristics, clinicopathological significance, and molecular biological function of PBX3 in CC. The expression levels of PBX3 were analyzed in CC cell lines and tumor specimens by real-time polymerase chain reaction (RT-PCR), Western blotting, and immunohistochemical staining. The clinicopathological characteristics associated with PBX3 expression were evaluated. An RNA interference approach was employed to suppress PBX3 expression in CC in vitro and in vivo, determine its role in cell proliferation and analyze its molecular function. We found that PBX3 expression was significantly upregulated in CC cell lines and clinical specimens compared with normal cells and adjacent nontumorous cervical tissues. PBX3 was an independent predictive factor of poor prognosis, and its expression was correlated with tumor diameter, pathological grading, lymph node metastasis, invasion depth, vascular invasion, and clinical stage of CC. Multivariate analysis suggested that PBX3 expression may represent an independent prognostic indicator of the survival of CC patients. CC patients with high PBX3 expression exhibited reduced overall survival compared with those with low PBX3 expression. Additionally, stable downregulation of PBX3 expression in CC cell lines suppressed cell proliferation and decreased p-AKT protein expression levels in vitro. Similarly, in vivo assays demonstrated that PBX3 downregulation in CC cells markedly inhibited tumor size and weight. Overall, we demonstrated that PBX3 can promote CC cell proliferation via the AKT signaling pathway and that it may serve as a prognostic marker. Our data indicate that inactivation of PBX3 may be an effective clinical treatment for CC.