CD147 reprograms fatty acid metabolism in hepatocellular carcinoma cells through Akt/mTOR/SREBP1c and P38/PPARα pathways

Blockade of Macrophage CD147 Protects Against Foam Cell Formation in Atherosclerosis

The persistence of macrophage-derived foam cells in the artery wall fuels atherosclerosis development. However, the mechanism of foam cell formation regulation remains elusive. We are committed to determining the role that CD147 might play in macrophage foam cell formation during atherosclerosis. In this study, we found that CD147 expression was primarily increased in mouse and human atherosclerotic lesions that were rich in macrophages and could be upregulated by ox-LDL. High-throughput compound screening indicated that ox-LDL-induced CD147 upregulation in macrophages was achieved through PI3K/Akt/mTOR signaling. Genetic deletion of macrophage CD147 protected against foam cell formation by impeding cholesterol uptake, probably through the scavenger receptor CD36. The opposite effect was observed in primary macrophages isolated from macrophage-specific CD147-overexpressing mice. Moreover, bioinformatics results indicated that CD147 suppression might exert an atheroprotective effect via various processes, such as cholesterol biosynthetic and metabolic processes, LDL and plasma lipoprotein clearance, and decreased platelet aggregation and collagen degradation. Our findings identify CD147 as a potential target for prevention and treatment of atherosclerosis in the future.

Anti-allergic drug azelastine suppresses colon tumorigenesis by directly targeting ARF1 to inhibit IQGAP1-ERK-Drp1-mediated mitochondrial fission

This study aimed to screen novel anticancer strategies from FDA-approved non-cancer drugs and identify potential biomarkers and therapeutic targets for colorectal cancer (CRC).

Methods: A library consisting of 1056 FDA-approved drugs was screened for anticancer agents. WST-1, colony-formation, flow cytometry, and tumor xenograft assays were used to determine the anticancer effect of azelastine. Quantitative proteomics, confocal imaging, Western blotting and JC-1 assays were performed to examine the effects on mitochondrial pathways. The target protein of azelastine was analyzed and confirmed by DARTS, WST-1, Biacore and tumor xenograft assays. Immunohistochemistry, gain- and loss-of-function experiments, WST-1, colony-formation, immunoprecipitation, and tumor xenograft assays were used to examine the functional and clinical significance of ARF1 in colon tumorigenesis.

Results: Azelastine, a current anti-allergic drug, was found to exert a significant inhibitory effect on CRC cell proliferation in vitro and in vivo, but not on ARF1-deficient or ARF1-T48S mutant cells. ARF1 was identified as a direct target of azelastine. High ARF1 expression was associated with advanced stages and poor survival of CRC. ARF1 promoted colon tumorigenesis through its interaction with IQGAP1 and subsequent activation of ERK signaling and mitochondrial fission by enhancing the interaction of IQGAP1 with MEK and ERK. Mechanistically, azelastine bound to Thr-48 in ARF1 and repressed its activity, decreasing Drp1 phosphorylation. This, in turn, inhibited mitochondrial fission and suppressed colon tumorigenesis by blocking IQGAP1-ERK signaling.

Conclusions: This study provides the first evidence that azelastine may be novel therapeutics for CRC treatment. ARF1 promotes colon tumorigenesis, representing a promising biomarker and therapeutic target in CRC.

Comprehensive analysis of key lncRNAs in HCV-positive hepatocellular carcinoma

INTRODUCTION

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. Despite the therapeutic advances in HCC in the past few decades, the mortality rate of HCC is still high. Hepatitis C (HCV) infection is one of the major etiological risk factors of HCCs. However, the underlying mechanisms of HCV-induced hepatocarcinogenesis remain largely unclear.

MATERIAL AND METHODS

Our study represented the comprehensive analysis of differentially expressed lncRNAs in HCV-positive HCC for the first time by analyzing the public dataset GSE17856. Co-expression network and gene ontology (GO) analysis revealed the functions of those differentially expressed lncRNAs.

RESULTS

We identified 256 upregulated lncRNAs and 198 downregulated lncRNAs in HCV- positive HCC compared to the normal liver tissues. Co-expression network and GO analysis showed that these lncRNAs were involved in regulating metabolism, energy pathways, proliferation and the immune response. Seven lncRNAs (LOC341056, CCT6P1, PTTG3P, LOC643387, LOC100133920, C3P1 and C22orf45) were identified as key lncRNAs and co-expressed with more than 100 differentially expressed genes (DEGs) in HCV-related HCC. Kaplan-Meier analysis showed that higher expression levels of LOC643387, PTTG3P, LOC341056, CCT6P1 and lower expression levels of C3P1 and C22orf45 were associated with shorter survival time in the TCGA dataset.

CONCLUSIONS

We believe that this study can provide novel potential therapeutic and prognostic biomarkers for HCV-positive HCC.

Assessment of Current Gene Therapy Practices in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer and the fifth most common cancer worldwide. HCC is recognized as the fourth most common cause of cancer related deaths worldwide due to the lack of effective early diagnostic tools, which often leads to individuals going undiagnosed until the cancer has reached late stage development. The current FDA approved treatments for late stage HCC provide a minimal increase in patient survival and lack tumor specificity, resulting in toxic systemic side effects. Gene therapy techniques, such as chimeric antigen receptor (CAR)-T Cells, viral vectors, and nanoparticles, are being explored as novel treatment options in various genetic diseases. Pre-clinical studies using gene therapy to treat in vitro and in vivo models of HCC have demonstrated potential efficacy for use in human patients. This review highlights genetic targets, techniques, and current clinical trials in HCC utilizing gene therapy.

Periostin antisense oligonucleotide prevents hepatic steatosis and fibrosis in a mouse model of non-alcoholic steatohepatitis

BACKGROUND AND AIM

Non-alcoholic steatohepatitis (NASH) is characterized by hepatic steatosis, inflammation, and hepatocellular injury with varying degrees of fibrosis. There are currently no established treatment approaches for NASH other than lifestyle interventions. Periostin, a matricellular protein required for tissue remodeling and fibrosis, plays an important role in hepatic steatosis and fibrosis and could be a potential target for NASH treatment. Advances in molecular biology and biochemical engineering have led to the development of antisense oligonucleotides (ASOs) that can inhibit target genes with no significant toxic effects. Herein, we investigated the therapeutic effects of periostin-targeting ASO (PNASO) in NASH.

METHODS

C57BL/6J mice were fed a choline-deficient, l-amino acid-defined, high-fat diet (CDAHFD) to induce NASH with or without intraperitoneal injection of mouse PNASO. To explore the role of periostin in hepatocellular steatosis, Hc3716 cells, an immortalized human hepatocyte line, were treated with recombinant periostin in vitro.

RESULTS

The induced periostin expression in the liver of CDAHFD-fed mice was significantly suppressed by PNASO. The deletion of hepatic periostin by PNASO significantly ameliorated hepatic steatosis while restoring the expression levels of peroxisome proliferator-activated receptor-alpha (PPAR-α) and its target genes. PNASO also inhibited hepatic fibrosis, reflected by the reduction of alpha-smooth muscle actin, collagen type I, and other fibrotic markers. In vitro experiments demonstrated that treatment with recombinant periostin increased cellular lipid accumulation in Hc3716 cells accompanied with the downregulation of PPAR-α.

CONCLUSIONS

Periostin-targeting ASO is a potential therapeutic approach for the efficient treatment of hepatic steatosis and fibrosis in NASH.

LncRNA RHPN1-AS1 accelerates proliferation, migration, and invasion via regulating miR-485-5p/BSG axis in hepatocellular carcinoma

It is reported that long noncoding RNA RHPN1-AS1 (lncRNA RHPN1-AS1) functions as an oncogene among multiple types of cancers; however, the effect of lncRNA RHPN1-AS1 in hepatocellular carcinoma (HCC) is left to be investigated. The main purpose of this work was to study the effects of lncRNA RHPN1-AS1/miR-485-5p system on proliferation, migration, and invasion in HCC and future investigate the latent mechanisms. Our work found that lncRNA RHPN1-AS1 was observably up-regulated in HCC tissues and cell lines, especially HCCLM3 and SMMC-7721 cells. LncRNA RHPN1-AS1 knockdown decreased the capacity of proliferation, invasion, and migration in HCCLM3 and SMMC-7721 cells, which could be crippled by miR-485-5p inhibitor. Besides, the expression of basigin (BSG) was decreased after lncRNA RHPN1-AS1 silence, indicating the function of lncRNA RHPN1-AS1/miR-485-5p/BSG axis in HCC progression. Our study opens novel insights to help understand the mechanisms of lncRNA RHPN1-AS1/miR-485-5p/BSG axis in HCC progression, which may provide a new therapeutic target for HCC treatment.

Loss of FBP1 promotes proliferation, migration, and invasion by regulating fatty acid metabolism in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the most common cancers in China. Recent studies have shown fatty acid metabolism is involved in the progression of various cancers through regulating the function of various types of cells. However, the relationship between fatty acid metabolism and tumorigenesis of ESCC remains unclear. Here, in this study, the expression of FBP1 was dramatically decreased in ESCC tissues compared with the adjacent non-ESCC tissues. The cell proliferation, migration, invasion and fatty acid metabolism were evaluated in ESCC cells using transfection of shFBP1 vectors. We found loss of FBP1 promoted ESCC cell proliferation, migration and invasion, which correlated with the activated fatty acid metabolism in vitro. Moreover, the content of phospholipids, triglycerides, neutral lipids and the protein expression levels of fatty acid metabolism related FASN, ACC1 and SREBP1C proteins were significantly increased following down-regulation of FBP1. Furthermore, FBP1 was found to be directly targeted by miR-18b-5p in ESCC cells. In addition, miR-18b-5p inhibitor treatment obviously reversed the increased fatty acid metabolism induced by loss of FBP1 in ESCC cells. These findings explored a detailed molecular mechanism of tumorigenesis and progression of ESCC and might provide a potential novel method to treat ESCC in clinic.

Efficacy and Mechanism of a Chinese Classic Prescription of Yueju in Treating Nonalcoholic Steatohepatitis and Protecting Hepatocytes from Apoptosis

Yueju, a famous classic Chinese prescription, has been extensively used in treating depression syndromes for hundreds of years. Recent studies have reported that Yueju showed good effects in treating metabolic diseases, such as obesity and hyperlipidemia. Nonalcoholic steatohepatitis (NASH), which leads to cirrhosis and severe cardiovascular diseases, is closely linked to obesity and abnormal lipid metabolism. In this study, Yueju could decrease the levels of alanine aminotransferase, aspartate transaminase, triglyceride, cholesterol, and low-density lipoprotein-C but increase the high-density lipoprotein-C in the serum of the NASH rat model induced by high-fat and high-cholesterol diet. Yueju could alleviate hepatosteatosis by increasing the phosphorylation of acetyl-CoA carboxylase and inhibiting the expression of fatty acid synthase and stearoyl-CoA desaturase 1. Yueju downregulated the expression of α-smooth muscle actin and collagen type 1A1, ameliorating the liver fibrilization. Yueju could also protect the hepatocytes from apoptosis by upregulating antiapoptosis protein Bcl-2 and X-linked inhibitor of apoptosis protein and downregulating apoptotic proteins Bax and cleaved poly ADP-ribose polymerase. Thus, Yueju could improve liver function, regulate lipid metabolism, alleviate hepatosteatosis and fibrosis, and protect hepatocytes from apoptosis against NASH. Yueju may be used as an alternative effective medicine for NASH treatment.

ZHX2 inhibits SREBP1c-mediated de novo lipogenesis in hepatocellular carcinoma via miR-24-3p

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide. Lipogenesis has been considered as a critical player in HCC initiation and progression. However, the underlying mechanism is still not fully understood. Here, we identified zinc fingers and homeoboxes 2 (ZHX2), an HCC-associated tumor suppressor, as an important repressor of de novo lipogenesis. Ectopic expression of ZHX2 significantly inhibited de novo lipogenesis in HCC cells and decreased expression of FASN, ACL, ACC1, and SCD1. In accordance with this, ZHX2 was negatively associated with SREBP1c, the master regulator of de novo lipogenesis, in HCC cell lines and human specimens. Results from silencing and overexpression demonstrated that ZHX2 inhibited de novo lipogenesis and consequent HCC progression via repression of SREBP1c. Furthermore, treatment with the SREBP1c inhibitor fatostatin dampened the spontaneous formation of tumors in liver-specific Zhx2 knockout mice. Mechanistically, ZHX2 increased expression of miR-24-3p transcriptionally, which targeted SREBP1c and led to its degradation. In conclusion, our data suggest a novel mechanism through which ZHX2 suppresses HCC progression, which may provide a new strategy for the treatment of HCC. © 2020 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Role of melatonin in the treatment of COVID-19; as an adjuvant through cluster differentiation 147 (CD147)

COVID-19 caused by the SARS-CoV-2 outbreak quickly has turned into a pandemic. However, no specific antiviral agent is yet available. In this communication, we aimed to evaluate the significance of CD147 protein and the potential protective effect of melatonin that is mediated by this protein in COVID-19. CD147 is a glycoprotein that is responsible for the cytokine storm in the lungs through the mediation of viral invasion. Melatonin use previously was shown to reduce cardiac damage by blocking the CD147 activity. Hence, melatonin, a safe drug, may prevent severe symptoms, reduce symptom severity and the adverse effects of the other antiviral drugs in COVID-19 patients. In conclusion, the use of melatonin, which is reduced in the elderly and immune-compromised patients, should be considered as an adjuvant through its CD147 suppressor and immunomodulatory effect.

Valine increases milk fat synthesis in mammary gland of gilts through stimulating AKT/MTOR/SREBP1 pathway†

Lactating mammary glands are among the most active lipogenic organs and provide a large percentage of bioactive lipids and calories for infant growth. The branched-chain amino acid (BCAA) valine is known to modulate fatty acids synthesis in adipose tissue; however, its effects on fat metabolism and the underlying mechanisms in mammary glands remain to be determined. Valine supplementation during late pregnancy significantly increased the contents of total milk fat, triglyceride, sphingomyelin, and polyunsaturated fatty acids in the colostrum of gilts. Further study in porcine mammary epithelial cells (PMECs) confirmed that valine upregulated the phosphorylation levels of AKT-activated MTOR and subsequently induced the nuclear accumulation of sterol regulatory element binding protein 1 (SREBP1), thus increasing the expression of proteins related to fatty acids synthesis and intracellular triacylglycerol content. Inhibition of AKT/MTOR signaling or silencing of SREBP1 in PMECs downregulates the expression of proteins related to fatty acids synthesis and intracellular triacylglycerol content. Our findings indicated that valine enhanced milk fat synthesis of colostrum in porcine mammary glands via the AKT/MTOR/SREBP1 signaling pathway.

A Prognostic Model Based on Six Metabolism-Related Genes in Colorectal Cancer

An increasing number of studies have shown that abnormal metabolism processes are closely correlated with the genesis and progression of colorectal cancer (CRC). In this study, we systematically explored the prognostic value of metabolism-related genes (MRGs) for CRC patients. A total of 289 differentially expressed MRGs were screened based on The Cancer Genome Atlas (TCGA) and the Molecular Signatures Database (MSigDB), and 72 differentially expressed transcription factors (TFs) were obtained from TCGA and the Cistrome Project database. The clinical samples obtained from TCGA were randomly divided at a ratio of 7 : 3 to obtain the training group (n = 306) and the test group (n = 128). After univariate and multivariate Cox regression analyses, we constructed a prognostic model based on 6 MRGs (AOC2, ENPP2, ADA, GPD1L, ACADL, and CPT2). Kaplan–Meier survival analysis of the training group, validation group, and overall samples proved that the model had statistical significance in predicting the outcomes of patients. Independent prognosis analysis suggested that this risk score might serve as an independent prognosis factor for CRC patients. Moreover, we combined the prognostic model and the clinical characteristics in a nomogram to predict the overall survival of CRC patients. Furthermore, gene set enrichment analysis (GSEA) was conducted to identify the enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways in the high- and low-risk groups, which might provide novel therapeutic targets for CRC patients. We discovered through the protein-protein interaction (PPI) network and TF-MRG regulatory network that 7 hub genes were retrieved from the PPI network and 4 kinds of differentially expressed TFs (NR3C1, MYH11, MAF, and CBX7) positively regulated 4 prognosis-associated MRGs (GSTM5, PTGIS, ENPP2, and P4HA3).

Deficiency of CD147 Attenuated Non-alcoholic Steatohepatitis Progression in an NLRP3-Dependent Manner

Cluster of differentiation 147 (CD147) is a transmembrane glycoprotein belonging to the immunoglobulin superfamily. CD147 overexpression has been reported to facilitate the development of hepatocellular carcinoma (HCC) and influence immunologic disorders. Although increased expression of CD147 was reported in non-alcoholic steatohepatitis (NASH), functions of CD147 in NASH have not been evaluated. Firstly, we confirmed that CD147 expression was increased in the liver tissues from methionine-choline-deficient (MCD) diet-induced NASH model mice and NASH patients. Mice with hepatocyte-specific CD147 deletion exhibited attenuated NASH phenotypes, including reduced steatosis, liver injury, hepatocyte apoptosis and inflammatory cytokines IL-1β/IL-18 secretion. Following the administration of the MCD diet, NLRP3 expression was increased gradually along with CD147 expression. Furthermore, CD147 deletion inhibited the NF-κB/NLRP3 signaling pathway in both MCD diet-induced mice and primary hepatocytes. Finally, CypA inhibitor TMN355 attenuated liver steatosis and injury and inhibited NF-κB/NLRP3 signaling pathway. Therefore, our results suggest that CD147 played a vital role in NASH pathogenesis by regulating the inflammatory response, and CypA/CD147 could be attractive therapeutic targets for NASH treatment.

Low UGP2 Expression Is Associated with Tumour Progression and Predicts Poor Prognosis in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a malignant tumour associated with a high mortality rate and poor prognosis worldwide. Uridine diphosphate-glucose pyrophosphorylase 2 (UGP2), a key enzyme in glycogen biosynthesis, has been reported to be associated with the occurrence and development of various cancer types. However, its diagnostic value and prognostic value in HCC remain unclear. The present study observed that UGP2 expression was significantly downregulated at both the mRNA and protein levels in HCC tissues. Receiver operating characteristic (ROC) curve analysis revealed that UGP2 may be an indicator for the diagnosis of HCC. In addition, Kaplan-Meier and Cox regression multivariate analyses indicated that UGP2 is an independent prognostic factor of overall survival (OS) in patients with HCC. Furthermore, gene set enrichment analysis (GSEA) suggested that gene sets negatively correlated with the survival of HCC patients were enriched in the group with low UGP2 expression levels. More importantly, a significant correlation was identified between low UGP2 expression and fatty acid metabolism. In summary, the present study demonstrates that UGP2 may contribute to the progression of HCC, indicating a potential therapeutic target for HCC patients.

Octyl gallate induces hepatic steatosis in HepG2 cells through the regulation of SREBP-1c and PPAR-gamma gene expression

Octyl gallate (OG) is an antioxidant commonly used in food, although there is no definition of its acceptable daily intake. There are reports in vitro and in vivo showing that food additives and drugs can alter lipid metabolism. Lipid droplet accumulation in hepatic cells is one of the main findings in the unregulated lipid metabolism and is strongly related to the development of nonalcoholic fatty liver disease (NAFLD). In this study, we investigated the effects of OG on lipid metabolism in the hepatocellular carcinoma cell line (HepG2). The results have shown, for the first time, that treatment with OG increased the overall amount of lipids, the triglyceride concentration, the lipid droplet area, and SREBP-1c and PPAR-γ gene expression. Taken together, the findings indicate that OG induces lipid droplet accumulation in HepG2 cells through the regulation of SREBP-1c and PPAR-γ gene expression without involving mTOR/S6K1 and may contribute to NAFLD when used as a food additive.

Magnesium isoglycyrrhizinate prevents the nonalcoholic hepatic steatosis via regulating energy homeostasis

Non-alcoholic fatty liver disease is a public health problem worldwide associated with high morbidity and hepatic steatosis, but no effective therapeutic interventions. Magnesium isoglycyrrhizinate (MGIG), a derivative of an active component of Glycyrrhiza glabra, is widely used for the treatment of inflammatory liver diseases due to its potent anti-inflammatory and hepatoprotective activities. Hence, this study aimed to study the effects of MGIG on hepatic steatosis in mice fed a high-fat diet (HFD). Oil Red O staining and transmission electron microscopy revealed a decrease in lipid accumulation in the liver after MGIG treatment along with improved mitochondrial ultramicrostructures. Metabonomic analysis demonstrated that MGIG intervention increased glutamate utilization in mitochondria by promoting the uptake of glutamate into the tricarboxylic acid (TCA) cycle. The NAD+ /NADH ratio and the expression of other lipid-metabolism-related genes were increased in MGIG-treated livers. Transcriptome sequencing showed that the expression of TLR4, an isoform of the innate immunity Toll-like receptors (TLRs), was significantly decreased after MGIG treatment, suggesting a link between the anti-inflammatory effects of MGIG and its suppression of lipidation. Our results reveal the potent effects of MGIG on lipid metabolism and suggest that hepatic TLR4 might be a crucial therapeutic target to regulate energy homeostasis in hepatic steatosis.

STIM1 is a metabolic checkpoint regulating the invasion and metastasis of hepatocellular carcinoma

Background: Cancer cells undergoing invasion and metastasis possess a phenotype with attenuated glycolysis, but enhanced fatty acid oxidation (FAO). Calcium (Ca²⁺)-mediated signaling pathways are implicated in tumor metastasis and metabolism regulation. Stromal-interaction molecule 1 (STIM1) triggered store-operated Ca²⁺ entry (SOCE) is the major route of Ca²⁺ influx for non-excitable cells including hepatocellular carcinoma (HCC) cells. However, whether and how STIM1 regulates the invasion and metastasis of HCC via metabolic reprogramming is unclear.

Methods: The expressions of STIM1 and Snail1 in the HCC tissues and cells were measured by immunohistochemistry, Western-blotting and quantitative PCR. STIM1 knockout-HCC cells were generated by CRISPR-Cas9, and gene-overexpression was mediated via lentivirus transfection. Besides, the invasive and metastatic activities of HCC cells were assessed by transwell assay, anoikis rate in vitro and lung metastasis in vivo. Seahorse energy analysis and micro-array were used to evaluate the glucose and lipid metabolism.

Results: STIM1 was down-regulated in metastatic HCC cells rather than in proliferating HCC cells, and low STIM1 levels were associated with poor outcome of HCC patients. During tumor growth, STIM1 stabilized Snail1 protein by activating the CaMKII/AKT/GSK-3β pathway. Subsequently, the upregulated Snail1 suppressed STIM1/SOCE during metastasis. STIM1 restoration significantly diminished anoikis-resistance and metastasis induced by Snail1. Mechanistically, the downregulated STIM1 shifted the anabolic/catabolic balance, i.e., from aerobic glycolysis towards AMPK-activated fatty acid oxidation (FAO), which contributed to Snail1-driven metastasis and anoikis-resistance.

Conclusions: Our data provide the molecular basis that STIM1 orchestrates invasion and metastasis via reprogramming HCC metabolism.

Hepatic CD147 knockout modulates liver steatosis and up-regulates autophagy in high-fat-diet-induced NAFLD mice

Nonalcoholic fatty liver disease (NAFLD) represents a global health problem. Impaired autophagy has been implicated in the pathogenesis of NAFLD, and CD147 is recognized to regulate lipid metabolism in a variety of cell types. This study was initiated with the aim to identify molecular makers expressed in hepatocytes that are significantly altered during the pathogenesis of NAFLD and closely associated with hepatic steatosis and autophagy. In this study, CD147 was found to be significantly associated with steatosis and autophagy in both clinical patients with NAFLD and NAFLD mouse models. In high-fat-diet-induced NAFLD mice, hepatic-specific CD147 knockout markedly reduced body weight, liver weight, serum aspartate aminotransaminase (AST) and alanine aminotransaminase (ALT), and liver steatosis. In addition, hepatic CD147 gene knockout noticeably promoted autophagy in NAFLD mice (LC3 expression was increased with decreased P62 expression; molecular markers of autophagy). Moreover, we found that CD147 expression was significantly associated with AKT/mTOR signaling pathway; thus, suggesting that CD147 is involved in the regulation of autophagy and steatosis in NAFLD. In conclusion, this study has provided in vivo evidence for the putative role of CD147 in the pathogenesis of NAFLD and a valuable experimental basis for considering CD147 as a therapeutic target to prevent hepatic steatosis in patients with NAFLD.

The fuel and engine: The roles of reprogrammed metabolism in metastasis of primary liver cancer

Metastasis and metabolism reprogramming are two major hallmarks of cancer. In the initiation and progression of cancer, tumor cells are known to undergo fundamental metabolic changes to sustain their development and progression. In recent years, much more attentions have been drawn to their important roles in facilitating cancer metastasis through regulating the biological properties. In this review, we summarized the recent progresses in the studies of metabolism reprogramming of cancer metastasis, particularly of primary liver cancer, and highlight their potential applications.

Lipid droplets: platforms with multiple functions in cancer hallmarks

Lipid droplets (also known as lipid bodies) are lipid-rich, cytoplasmic organelles that play important roles in cell signaling, lipid metabolism, membrane trafficking, and the production of inflammatory mediators. Lipid droplet biogenesis is a regulated process, and accumulation of these organelles within leukocytes, epithelial cells, hepatocytes, and other nonadipocyte cells is a frequently observed phenotype in several physiologic or pathogenic situations and is thoroughly described during inflammatory conditions. Moreover, in recent years, several studies have described an increase in intracellular lipid accumulation in different neoplastic processes, although it is not clear whether lipid droplet accumulation is directly involved in the establishment of these different types of malignancies. This review discusses current evidence related to the biogenesis, composition and functions of lipid droplets related to the hallmarks of cancer: inflammation, cell metabolism, increased proliferation, escape from cell death, and hypoxia. Moreover, the potential of lipid droplets as markers of disease and targets for novel anti-inflammatory and antineoplastic therapies will be discussed.

SIK2 enhances synthesis of fatty acid and cholesterol in ovarian cancer cells and tumor growth through PI3K/Akt signaling pathway

Salt-inducible kinase 2 (SIK2) has been established as a regulator of diverse biological processes including cell metabolism. A recent study has reported that SIK2 is required for adipocyte-induced ovarian cancer (OC) survival through facilitating fatty acid oxidation. However, whether SIK2 also plays a role in the lipid synthesis in OC cells remains elusive. Here, we showed that SIK2 significantly promoted the lipid synthesis in OC cells. On the one hand, SIK2 enhanced fatty acid synthesis through upregulating the expression of sterol regulatory element binding protein 1c (SREBP1c) and thus the transcription of major lipogenic enzyme FASN. On the other hand, SIK2 promoted cholesterol synthesis through upregulating the expression of sterol regulatory element binding protein 2 (SREBP2) and thus the transcription of major cholesterol synthesis enzymes HMGCR. Moreover, PI3K/Akt signaling pathway was found to be involved in the upregulation of SREBP1c and SREBP2 in OC cells. Moreover, in vitro and in vivo assays indicated that the SIK2-regulated fatty acid and cholesterol synthesis played a critical role in the growth of OC cells. Our findings demonstrate that SIK2 is a critical regulator of lipid synthesis in OC cells and thus promotes OC growth, which provides a strong line of evidence for this molecule to be used as a therapeutic target in the treatment of this malignancy.

L-Carnitine Is Involved in Hyperbaric Oxygen-Mediated Therapeutic Effects in High Fat Diet-Induced Lipid Metabolism Dysfunction

Lipid metabolism dysfunction and obesity are serious health issues to human beings. The current study investigated the effects of hyperbaric oxygen (HBO) against high fat diet (HFD)-induced lipid metabolism dysfunction and the roles of L-carnitine. C57/B6 mice were fed with HFD or normal chew diet, with or without HBO treatment. Histopathological methods were used to assess the adipose tissues, serum free fatty acid (FFA) levels were assessed with enzymatic methods, and the endogenous circulation and skeletal muscle L-carnitine levels were assessed with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Additionally, western blotting was used to assess the expression levels of PPARα, CPT1b, pHSL/HSL, and UCP1. HFD treatment increased body/adipose tissue weight, serum FFA levels, circulation L-carnitines and decreased skeletal muscle L-carnitine levels, while HBO treatment alleviated such changes. Moreover, HFD treatment increased fatty acid deposition in adipose tissues and decreased the expression of HSL, while HBO treatment alleviated such changes. Additionally, HFD treatment decreased the expression levels of PPARα and increased those of CPT1b in skeletal muscle, while HBO treatment effectively reverted such changes as well. In brown adipose tissues, HFD increased the expression of UCP1 and the phosphorylation of HSL, which was abolished by HBO treatment as well. In summary, HBO treatment may alleviate HFD-induced fatty acid metabolism dysfunction in C57/B6 mice, which seems to be associated with circulation and skeletal muscle L-carnitine levels and PPARα expression.

Effect of divergence in residual feed intake on expression of lipid metabolism-related genes in the liver of meat-type ducks1

Lipid metabolism is considered one of the important factors affecting residual feed intake (RFI). However, the relationship between RFI and expression of lipid metabolism-related genes is unknown in meat-type ducks. To address this issue, a total of 1,000 male meat-type ducks with similar body weight were randomly selected to measure body weight gain and feed intake from 21 to 42 d of age to estimate RFI. The 8 greatest- (high RFI [HRFI]) and lowest- (low RFI [LRFI]) ranking birds were then selected for the present study. Relative expressions of key genes, namely sirtuin 1 (Sirt1), forkhead box O1 (Foxo1), peroxisome proliferator-activated receptor gamma (PPARγ), sterol regulatory element-binding transcription factor 1c (SREBP-1c), fas cell surface death receptor (FAS), acetyl-CoA carboxylase alpha (ACC), carnitine palmitoyltransferase 1A (CPT1A), and acyl-CoA oxidase 1 (ACOX1), were then determined in the HRFI and LRFI ducks by quantitative PCR. The results showed that RFI, feed conversion ratio (FCR), and average daily feed intake (ADFI) were significantly lower (P < 0.05) in LRFI ducks than in HRFI ducks. In addition, expression of Sirt1, Foxo1, CPT1A, and ACOX1 were significantly higher in LRFI ducks than in HRFI ducks (P < 0.05), whereas PPARγ and FAS expression levels were significantly lower in LRFI ducks than in HRFI ducks (P < 0.01). Correlation analysis showed that Sirt1, CPT1A, and ACOX1 expressions were significantly negatively correlated with FCR (r = -0.81 to -0.93; P < 0.01), whereas PPARγ and FAS expressions were significantly positively correlated with FCR (r = 0.74 to 0.87; P < 0.01). PPARγ expression was significantly positively correlated with RFI (r = 0.83; P < 0.01), whereas CPT1A and ACOX1 expressions were significantly negatively correlated with RFI (r = -0.84 to -0.89; P < 0.01). Sirt1 mRNA expression was positively correlated with Foxo1, CPT1A, and ACOX1 mRNA expression (r = 0.78 to 0.92; P < 0.01). Association of Foxo1 with CPT1A and ACOX1 was positive (r = 0.88 to 0.96; P < 0.01). These results suggest that genes related to fatty acid oxidation are upregulated in the liver of ducks with high feed efficiency, while genes associated with lipid synthesis are downregulated. Furthermore, the inclusion of lipid metabolism-related genes in future breeding programs might be beneficial for selecting ducks with greater feed efficiency phenotype.

Pathogenetic, Prognostic, and Therapeutic Role of Fatty Acid Synthase in Human Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common solid tumors worldwide, characterized by clinical aggressiveness, resistance to conventional chemotherapy, and high lethality. Consequently, there is an urgent need to better delineate the molecular pathogenesis of HCC to develop new preventive and therapeutic strategies against this deadly disease. Noticeably, emerging evidence indicates that proteins involved in lipid biosynthesis are important mediators along the development and progression of HCC in humans and rodents. Here, we provide a comprehensive overview of: (a) The pathogenetic relevance of lipogenic proteins involved in liver carcinogenesis, with a special emphasis on the master fatty acid regulator, fatty acid synthase (FASN); (b) The molecular mechanisms responsible for unrestrained activation of FASN and related fatty acid biosynthesis in HCC; (c) The findings in experimental mouse models of liver cancer and their possible clinical implications; (d) The existing potential therapies targeting FASN. A consistent body of data indicates that elevated levels of lipogenic proteins, including FASN, characterize human hepatocarcinogenesis and are predictive of poor prognosis of HCC patients. Pharmacological or genetic blockade of FASN is highly detrimental for the growth of HCC cells in both in vitro and in vivo models. In conclusion, FASN is involved in the molecular pathogenesis of HCC, where it plays a pivotal role both in tumor onset and progression. Thus, targeted inhibition of FASN and related lipogenesis could be a potentially relevant treatment for human HCC.

SPIN1 triggers abnormal lipid metabolism and enhances tumor growth in liver cancer

Abnormal lipid metabolism plays crucial roles in the development of cancer. Spindlin 1 (SPIN1) involving the process of spindle organization and chromosomal stability serves as an important player in the carcinogenesis. In this study, we try to identify the new function of SPIN1 in lipid metabolism of liver cancer. Tissue microarray showed that 75% (60/80) of hepatocellular carcinoma (HCC) tissues were positive for SPIN1, which was highly expressed in clinical HCC samples and positively associated with malignancy of HCC. Strikingly, SPIN1 could modulate abnormal lipid metabolism by increasing intracellular triglycerides, cholesterols, and lipid droplets in hepatoma cells, which could remarkably enhance the proliferation of hepatoma cells. Mechanistically, SPIN1 up-regulated FASN in hepatoma cells. SPIN1 co-activated transcriptional factor SREBP1c in the promoter of FASN through interaction with SREBP1c. Moreover, SPIN1 promoted the growth of liver cancer in vitro and in vivo and the levels of intracellular triglycerides, cholesterols and lipid droplets were increased in the tumor tissues from mice. In conclusion, SPIN1 modulates abnormal lipid metabolism and enhances growth of liver cancer through SREBP1c-triggered FASN signaling. Therapeutically, SPIN1 may serve as a novel target for HCC.

NPAS2 Contributes to Liver Fibrosis by Direct Transcriptional Activation of Hes1 in Hepatic Stellate Cells

Recently, emerging evidence shows that dysregulation of circadian genes is closely associated with liver fibrosis. However, how dysregulation of circadian genes promotes liver fibrosis is unknown. In this study, we show that neuronal PAS domain protein 2 (NPAS2), one of the core circadian molecules that has been shown to promote hepatocarcinoma cell proliferation, significantly contributed to liver fibrogenesis. NPAS2 is upregulated in hepatic stellate cells (HSCs) after fibrogenic injury, which subsequently contributes to the activation of HSCs. Mechanistically, NPAS2 plays a profibrotic role via direct transcriptional activation of hairy and enhancer of split 1 (Hes1), a critical transcriptor of Notch signaling for the fibrogenesis process, in HSCs. Our findings demonstrate that NPAS2 plays a critical role in liver fibrosis through direct transcriptional activation of Hes1, indicating that NPAS2 may serve as an important therapeutic target to reverse the progression of liver fibrosis.

Dual effects of an anti-CD147 antibody for Esophageal cancer therapy

Background: Esophageal cancer is a highly aggressive neoplasm. Targeted therapy has been proven to be a promising way for cancer therapy. Here, we report a novel anti-CD147 antibody for esophageal cancer therapy, which is a chimeric antibody with modified glycoform in Fc region. Methods: ADCC assay was used to explore the antitumor efficacy of Metuzumab against esophageal cancer in vitro. Wound healing assay and Boyden Chamber invasion assay were performed to explore whether Metuzumab could inhibit migration and invasion of esophageal cancer in vitro. Insulin-like growth factors 1 (IGF-1) and PI3k/Akt was assayed for elaborating antagonistic mechanism of Metuzumab in migration and invasion of esophageal cancer cells. Subcutaneous xenograft nude mouse model was used to investigate the antitumor efficacy of Metuzumab against esophageal cancer in vivo. The esophageal cancer tissue microarrays (TMA) was examined for identification of association of CD147 with lymph node metastasis, and the footpad xenograft nude mouse model was used to explore whether Metuzumab could inhibit lymph node metastasis of esophageal cancer in vivo. Results: The results showed that Metuzumab exhibited higher ADCC compared to the wild type antibody cHAb18. Metuzumab inhibited migration and invasion of esophageal cancer through blockade of CD147 in vitro. The results of Western blot showed Metuzumab might inhibit migration and invasion of esophageal cancer cells through suppressing activation of PI3k/Akt and expression of IGF-1. Experiments in vivo showed that Metuzumab exhibited significant antitumor efficacy and inhibited lymph node metastasis of esophageal cancer in xenograft models. The immunochemical staining of TMA showed CD147 was high-expressed on various kinds of esophageal cancer tissues and associated with the grade of lymph node-metastasis. Conclusions: The in vitro and in vivo study demonstrated dual effects of Metuzumab in effectively mediating ADCC by activating effector cells, and inhibiting metastasis of esophageal cancer through blockade the function of CD147, providing justification for moving Metuzumab forward to clinical development in esophageal cancer.

CD147 promotes glucose metabolism, invasion and metastasis via PI3K/AKT pathway in oral squamous cell carcinomas

Background

The incidence of oral cancers, especially that of oral squamous cell carcinoma (OSCC), has increased significantly in the last few decades. Aggressive tumor progression and metastasis are the key factors responsible for the high mortality rate associated with OSCC. CD147 is known to play a key role in tumor metastasis and is associated with poor prognosis in oral cancer. It is also a crucial regulator of glucose metabolism in cancer cells. The aim of this study was to determine the effect of CD147 on OSCC invasiveness, metastasis and glucose metabolism, as well as the underlying mechanism.

Methods

CD147 was knocked down in the human OSCC lines SCC-25 and CAL-27, and both the wild-type and knockdown cells were then stably transfected with PI3K cDNA. Glucose metabolism and in vitro migration of the OSCC cells were respectively analyzed by glucose uptake and lactate secretion assays, and transwell assay.

Results

Knocking down CD147 in the OSCC cells significantly reduced their migration, and decreased glucose metabolism. The inhibitory effects of blocking CD147 were reversed upon PI3K overexpression.

Conclusions

CD147 mediates its oncogenic effects via the PI3K/AKT pathway, and is a potential prognostic factor and therapeutic target for OSCC.

Knockdown expression of MECR, a novel gene of mitochondrial FAS II inhibits growth and colony-formation, promotes apoptosis of hepatocelluar carcinoma cells

Mitochondrial trans-2-enoyl-CoA reductase (MECR) is a protein-coding gene, and the protein encoded by this gene is an oxidoreductase that catalyzes the last step in mitochondrial fatty acid synthesis (mtFASII). Numerous studies have shown disorder of lipid metabolism is closely related with malignance, especially in liver cancer. Through pre-experiment, we found that the expression of MECR gene was highly expressed in hepatocelluar carcinoma (HCC) cell lines in vitro. This suggests that the MECR gene may play a role of oncogene in HCC. Therefore, we conducted a preliminary experimental study on the role of MECR gene in HCC cells in vitro. Objective to explore whether the MECR gene can affect the malignant biological behavior of HCC. We selected HCC cell line BEL-7404 as experimental cell, which involves the highest expression of MECR in the pre-experiment. We constructed MECR knockdwon lentivirus vector, and then infected HCC cell lines to down-regulate MECR expression, and establish negative control group (NC). Through various experiments of cytology, our study showed that knockdown of MECR inhibited cell proliferation and colony formation, promoted apoptosis, and inhibited metastasis in HCC cell lines BEL-7404. MECR might serve as a novel gene therapeutic target for the treatment of HCC. Further study is needed to elucidate the signaling pathway through which MECR functions in HCC.

The role of Wnt signaling pathway in tumor metabolic reprogramming

The occurrence and development of tumors is a complex process involving long-term multi-factor participation. In this process, tumor cells from a set of abnormal metabolic patterns that are different from normal cells. This abnormal metabolic change is called metabolic reprogramming of tumors. Wnt signaling pathway is one of the critical signaling pathways regulating cell proliferation and differentiation. In recent years, it has been found that Wnt signaling participates in the occurrence and development of malignant tumors by affecting metabolic reprogramming. This paper reviews the role of Wnt signaling in tumor metabolic reprogramming to provide crucial theoretical guidance for targeted therapy and drug response of tumors.

Silibinin A decreases statin‑induced PCSK9 expression in human hepatoblastoma HepG2 cells

Hypercholesterolemia is one of the major risk factors for the occurrence and development of atherosclerosis. The most common drugs used to treat hypercholesterolemia are 3‑hydroxy‑3‑methyl‑glutaryl‑CoA reductase inhibitors, known as statins. Statins induce a beneficial increase in the levels of the low density lipoprotein receptor (LDLR) and additionally upregulate proprotein convertase subtilisin/kexin type 9 (PCSK9), which leads to LDLR degradation. This process causes a negative feedback response that attenuates the lipid lowering effects of statins. Therefore, the development of PCSK9 inhibitors may increase the lipid‑lowering functions of statins. In the present study, a drug‑screening assay was developed using the human PCSK9 promoter, based on data from a dual‑luciferase reporter assay, and the efficacies of various compounds from Traditional Chinese Medicine were examined. Among the compounds examined, SIL was demonstrated to function by targeting PCSK9. It was identified that SIL treatment decreased the expression levels of PCSK9 in HepG2 cells by decreasing the activity of the PCSK9 promoter in a dose‑and time‑dependent manner. Notably, SIL antagonized the statin‑induced phosphorylation of the p38 MAPK signaling pathway. The present study suggested that SIL may be developed as a novel PCSK9 inhibitor that may increase the efficiency of statin treatment.

Aberrant lipid metabolism as a therapeutic target in liver cancer

INTRODUCTION

Hepatocellular carcinoma (HCC) is one of the most common and lethal cancers. Progress has been made in treatment of HCC; however, improved outcomes are much needed. The increased metabolic needs of cancer cells underscore the importance of metabolic pathways in cancer cell survival. Lipid metabolism has a role in HCC development; aberrant overexpression of several key enzymes is seen in many solid human tumors. Areas covered: We discuss aberrant lipid metabolism and the promise of multiple targets, in particular related to HCC treatment. We searched PubMed and clinicaltrials.gov for published and unpublished studies from 2000 to 2019. These terms were used: lipids, fatty acid metabolism, lipid metabolism, liver cancer, HCC, de novo fatty acid synthesis, ATP citrate lyase, stearoyl CoA denaturase, fatty acid synthase, acetyl coenzyme A carboxylase, CD147, KLF4, monoglyceride lipase, AMP activated protein kinase. Expert opinion: The importance of dysregulation of fatty acid synthesis in cancer is a growing area of research. HCC demonstrates significant alteration in lipid metabolism, representing great potential as a target for novel therapeutics. Various agents have demonstrated promising anti-neoplastic activity. This strategy deserves further development for improved outcomes.

Targeting the mTOR regulatory network in hepatocellular carcinoma: Are we making headway?

The mechanistic target of rapamycin (mTOR) pathway coordinates organismal growth and homeostasis in response to growth factors, nutrients, and cellular energy stage. The pathway regulates several major cellular processes and is implicated in various pathological conditions, including hepatocellular carcinoma (HCC). This review summarizes recent advances of the mTOR pathway, highlights the potential of the mTOR pathway as a therapeutic target, and explores clinical trials targeting the mTOR pathway in HCC. Although the review focuses on the mTOR pathway involved in HCC, more comprehensive discussions (eg, developing a rational design for future trials targeting the mTOR pathway) are also applicable to other tumors.

Down-regulation of PKM2 decreases FASN expression in bladder cancer cells through AKT/mTOR/SREBP-1c axis

Fatty acid synthase (FASN) catalyzing the terminal steps in the de novo biogenesis of fatty acids is correlated with low survival and high disease recurrence in patients with bladder cancer. Pyruvate kinase M2 (PKM2) regulates the final step of glycolysis levels and provides a growth advantage to tumors. However, it is unclear whether the change of PKM2 has an effect on FASN and what is the mechanisms underlying. Here we describe a novel function of PKM2 in control of lipid metabolism by mediating transcriptional activation of FASN, showing the reduced expression of sterol regulatory element binding protein 1c (SREBP-1c). We first discovered that PKM2 physically interacts with the SREBP-1c using biochemical approaches, and downregulation of PKM2 reduced the expression of SREBP-1c by inactivating the AKT/mTOR signaling pathway, which in turn directly suppressed the transcription of major lipogenic genes FASN to reduce tumor growths. Furthermore, either PKM2 inhibitor-Shikonin or FASN inhibitor-TVB-3166 alone induced a strong antiproliferative and anticolony forming effect in bladder cancer cell line. The combination of both inhibitors exhibits a super synergistic effect on blocking the bladder cancer cells growth. It provides a new target and scientific basis for the treatment of bladder cancer.

CD147 increases mucus secretion induced by cigarette smoke in COPD

BACKGROUND

CD147 is expressed in many tissues and is involved in many inflammatory diseases. Emerging evidence suggests that the overproduction of mucus is a malignant factor in chronic obstructive pulmonary disease (COPD), which results in severe airway obstruction and repeated airway infections. However, it is still unclear whether CD147 is involved in mucus production in COPD.

METHODS

We determined the expression levels of CD147 and MUC5AC by immunohistochemistry in 42 human lung specimens from three groups (non-smokers without COPD, smokers without COPD and smokers with COPD). For the in vitro experiment, human bronchial epithelial (HBE) cells were treated with cigarette smoke (CS) extract to establish a mucus secretion model; then, CD147 and MUC5AC production were detected by RT-PCR, Western blotting and ELISA. To determine how CD147 is involved in MUC5AC secretion, HBE cells were transfected with small interfering RNA to silence CD147 and pretreated with inhibitors of MMP9 and p38 MAPK, which are common signaling molecules involved in MUC5AC secretion; then, MUC5AC expression was evaluated.

RESULTS

Compared with the expression levels in the non-smokers and smokers without COPD, CD147 and MUC5AC expression levels were higher in the smokers with COPD. In the in vitro experiment, CD147 and MUC5AC expression levels were significantly increased after CS extract incubation compared with those after no treatment. Silencing CD147 by siRNA decreased the CS extract-induced MUC5AC secretion and MMP9 and phosphorylated p38 MAPK production. In addition, inhibiting MMP9 or p38 MAPK decreased the CS extract-induced MUC5AC secretion.

CONCLUSIONS

In lung specimens, CD147 and MUC5AC expression levels were increased in COPD patients. Increased CD147 levels induced by CS extract could stimulate MUC5AC secretion through the MMP9 and p38 MAPK signaling pathway in HBE cells. Therefore, the regulation of CD147 could be a promising target for mucus hypersecretion in COPD.

Oxidative stress mediated by lipid metabolism contributes to high glucose-induced senescence in retinal pigment epithelium

Retinal pigment epithelium (RPE) dysfunction is thought to increase the risk of the development and progression of diabetic retinopathy (DR), the leading cause of blindness. However, the molecular mechanism behind high glucose-induced RPE cell damage is still blurred. We reported that ARPE-19 exposed to 25 mM glucose for 48 h did not induce apoptosis, but senescence validated by SA-β-Gal staining, p21 expression and cell cycle distribution. High glucose also increased oxidant species that exerted a pivotal role in senescence, which could be relieved by the treatment with antioxidant N-acetylcysteine (NAC). The accumulation of lipid droplets and the increase of lipid oxidation were also observed in ARPE-19 treated with high glucose. And the supplementation of free fatty acids (FFAs) indicated that lipid metabolism was associated with the generation of hydrogen peroxide (H₂O₂) and subsequent senescence in ARPE-19. PI3K/Akt/mTOR signaling pathway was shown to be responsible for the accumulation of intracellular lipids by regulating fatty acid synthesis, which in turn controlled senescence. Furthermore, high glucose induced autophagy in ARPE-19 with the treatment of glucose for 48 h, and autophagy inhibitor hydroxychloroquine (HCQ) or bafilomycin further aggravated the senescence, accompanying by an increase in oxidant species. Whereas, prolonged high glucose exposure inhibited autophagy and increased apoptotic cells. Experiments above provide evidence that lipid metabolism plays an important role in oxidative stressed senescence of RPE.

Pro-angiogenic Role of Danqi Pill Through Activating Fatty Acids Oxidation Pathway Against Coronary Artery Disease

Coronary artery disease (CAD) is one of the leading causes of deaths worldwide. Energy metabolism disorders, including a reduction in fatty acids oxidation and upregulation of glycolysis pathway, are involved in the process of CAD. Therapeutic angiogenesis has become a promising treatment for CAD. Traditional Chinese medicines, such as Danqi Pill (DQP), have been proven to be effective in treating CAD in China for many years. However, the pro-angiogenic effects of DQP based on fatty acids oxidation are still unknown and the mechanism is worthy of investigation. In this study, left anterior descending (LAD) coronary artery was ligated to induce the CAD models in vivo, and cardiac functions were examined using echocardiography. Human umbilical vein endothelial cells (HUVEC) were subjected to H₂O₂-induced oxidative stress in vitro. The effects of DQP on CAD rat models and in vitro HUVEC were detected. Our results showed that DQP had cardio-protective effects in rat model. The intensity of capillaries in the marginal area of infarction of the rat heart was increased remarkably in DQP group, and the expression of PPARα and VEGF-2 were increased. The key enzymes involved in the transportation and intake of fatty acids, including CPT1A and CD36, both increased. In H₂O₂-induced endothelial cells injury models, DQP also showed protective roles and promoted capillary-like tube formation. DQP up-regulated key enzymes in fatty acids oxidation in H₂O₂-treated HUVEC. In addition, inhibition of CPT1A compromised the pro-angiogenic effects of DQP. In conclusion, fatty acids oxidation axis PPARα-CD36-CPT1A was involved in the pro-angiogenic roles of DQP against CAD. Cardiac CPT1A may serve as a target in therapeutic angiogenesis in clinics.

LAMP3 regulates hepatic lipid metabolism through activating PI3K/Akt pathway

Lysosome associated membrane protein 3 (LAMP3), a highly glycosylated protein, is one member of the LAMPs family. LAMPs family plays a critical role in the autolysosome fusion process. Autophagy was recently confirmed to regulate hepatic lipolysis. However, the physiological function of LAMP3 in lipid metabolism is not clear. In the current study, we discovered that the LAMP3 expression level was higher in the liver tissues of non-alcoholic fatty liver disease (NAFLD) patients and high-fat diet and ob/ob mice than in the matched control groups. LAMP3 expression was also obviously increased in hepatocellular carcinoma (HCC) cells treated with free fatty acids. Moreover, marked accumulation of intracellular lipid droplets and triglycerides (TG) was observed after LAMP3 overexpression in HCC cells. Further study showed that LAMP3 overexpression activated Akt and upregulated the expression of the lipogenic enzymes FASN and SCD-1 in HepG2 cells. Additionally, the increased TG content induced by LAMP3 overexpression was attenuated by treatment with a PI3K/Akt pathway inhibitor. Our findings demonstrated that LAMP3 is an important regulator of hepatic lipid metabolism, which provides a line of evidence for taking LAMP3 as a drug target in lipid metabolism disorder-associated diseases, such as NAFLD and obesity.

Nicotine induces oral dysplastic keratinocyte migration via fatty acid synthase-dependent epidermal growth factor receptor activation

Despite advances in diagnostic and therapeutic management, oral squamous cell carcinoma (OSCC) patient survival rates have remained relatively unchanged. Thus, identifying early triggers of malignant progression is critical to prevent OSCC development. Traditionally, OSCC initiation is elicited by the frequent and direct exposure to multiple tobacco-derived carcinogens, and not by the nicotine contained in tobacco products. However, other nicotine-containing products, especially the increasingly popular electronic cigarettes (e-cigs), have unknown effects on the progression of undiagnosed tobacco-induced oral premalignant lesions, specifically in regard to the effects of nicotine. Overexpression of fatty acid synthase (FASN), a key hepatic de novo lipogenic enzyme, is linked to poor OSCC patient survival. Nicotine upregulates hepatic FASN, but whether this response occurs in oral dysplastic keratinocytes is unknown. We hypothesized that in oral dysplastic keratinocytes, nicotine triggers a migratory phenotype through FASN-dependent epidermal growth factor receptor (EGFR) activation, a common pro-oncogenic event supporting oral carcinogenesis. We report that in oral dysplastic cells, nicotine markedly upregulates FASN leading to FASN-dependent EGFR activation and increased cell migration. These results raise potential concerns about e-cig safety, especially when used by former tobacco smokers with occult oral premalignant lesions where nicotine could trigger oncogenic signals commonly associated with malignant progression.

Downregulation of CPT2 promotes tumorigenesis and chemoresistance to cisplatin in hepatocellular carcinoma

Background

Cancer cells often have characteristic changes in metabolism. Besides Warburg effect, abnormal lipid metabolism is also considered as one of the most typical metabolic symbols of cancer. Thus, understanding the mechanisms of cell metabolic reprogramming may provide a potential avenue for cancer treatment.

Materials and methods

In total, 41 pairs of matched samples of primary hepatocellular carcinoma (HCC) and adjacent non-cancerous liver tissues were collected. Afterward, we performed quantitative reverse transcriptase polymerase chain reaction to investigate carnitine palmitoyltransferase-2 (CPT2) expression and then systematically analyzed its relationship with clinicopathologic features. We further performed proliferation, colony formation, migration and invasion, drug resistance, and lipogenesis assays to determine the function of CPT2 in HCC.

Results

In this study, we have identified CPT2 which is the rate-limiting enzyme of fatty acid oxidation, downregulated in HCC and was significantly associated with tumor histological differentiation and venous invasion. In vitro studies demonstrated that knockdown of CPT2 remarkably enhanced the tumorigenic activity and metastatic potential of hepatoma cells. In addition, CPT2 silencing induced chemoresistance to cisplatin. Mechanistically, low expression of CPT2 promoted cancer cell lipogenesis via upregulation of stearoyl-CoA desaturase-1, the key enzyme involved in the synthesis of monounsaturated fatty acids, at both mRNA and protein levels in hepatoma cell line.

Conclusion

Altogether, our findings demonstrate that CPT2 has a critical role in HCC progression and chemoresistance and may potentially serve as a novel prognostic marker and therapeutic target for HCC treatment.

Down-Regulated miR-125a-5p Promotes the Reprogramming of Glucose Metabolism and Cell Malignancy by Increasing Levels of CD147 in Thyroid Cancer

BACKGROUND

CD147 contributes to increased aerobic glycolysis through which it promotes tumor growth. Accumulating evidence suggests that CD147 exerts a variety of functions in thyroid cancer (TC) progression but the molecular mechanisms and therapeutic value of CD147 remain unclear.

METHODS

CD147 levels in TC tissues were analyzed to assess its relationship with prognosis and disease progression. A microRNA (miRNA) microarray and bioinformatics approach were used to identify microRNA regulators of CD147 through measurement of the expression and functions of these miRNAs in TC tissues and cell lines. Precursor miRNA-transfected cells were used to assess regulation of CD147 by miRNA. The effect of miRNA on TC cells via inhibition of glycolysis through CD147 targeting was also evaluated.

RESULTS

We found that miR-125a-5p regulates CD147 and is negatively correlated with its expression and function. Moreover, CD147 knockdown or increased miR-125a-5p expression significantly reduced the viability, migration, and invasion of TC cells. Our mechanistic studies demonstrate that, through directly repressing the expression of the CD147 protein, miR-125a-5p suppresses aerobic glycolysis and lactate production and subsequently reduces TC cell viability, migration, and invasion, thereby exerting tumor suppressor functions.

CONCLUSIONS

The novel connection identified between miR-125a-5p and CD147 suggests a new diagnostic and prognostic role for miR-125a-5p and that CD147 inhibition may be a candidate therapeutic target in the therapy of for TC.

Fatty acid oxidation contributes to IL-1β secretion in M2 macrophages and promotes macrophage-mediated tumor cell migration

Tumor-associated macrophages (TAMs) are predominantly M2 phenotype in solid cancers including hepatocellular carcinoma (HCC). Though differentiation of M2 macrophages has been recently linked to fatty acid oxidation (FAO), whether FAO plays a role in functional maintenance of M2 macrophages is still unclear. Here, we used an in vitro model to mimic TAM-HCC interaction in tumor microenvironment. We found that M2 monocyte-derived macrophages (MDMs) enhanced the proliferation, migration, and invasion of HCC cells through an FAO-dependent way. Further investigations identified that IL-1β mediated the pro-migratory effect of M2 MDM. Using etomoxir and siRNA to inhibit FAO and palmitate to enhance FAO, we showed that FAO was responsible for the up-regulated secretion of IL-1β and, thus, the pro-migratory effect in M2 MDMs. In addition, we proved that IL-1β induction was reactive oxygen species and NLRP3-dependent. Our study demonstrates that FAO plays a key role in functional human M2 macrophages by enhancing IL-1β secretion to promote HCC cell migration. These findings provide evidence for different dependency of energy sources in macrophages with distinct phenotypes and functions, and suggest a novel strategy to treat HCC by reprogramming cell metabolism or modulating tumor microenvironment.

Nicotine increases apoptosis in HUVECs cultured in high glucose/high fat via Akt ubiquitination and degradation

It is well-documented that nicotine, the main active ingredient in cigarettes, results in endothelial cell injury in numerous diseases. However, whether nicotine plays a crucial role in endothelial cell injury in diabetes and the exact molecular mechanism that mediates this process have not been fully elucidated. The current study aimed to investigate the effects of nicotine on endothelial cell injury in diabetes and the specific molecular mechanism by which it plays a role. Human umbilical vein endothelial cells (HUVECs) were incubated in HG/HF media and treated with nicotine, PYR-41 (a selective ubiquitin E1 inhibitor), Akt-overexpressing adenovirus, or TTC3 and MUL1 shRNA adenovirus. Cell viability was subsequently detected by the CCK8 assay, and apoptosis was examined by caspase-3 cleavage and activity analysis. Compared to the HG/HF incubated group, nicotine incubation significantly decreased cell survival and increased apoptosis. Moreover, nicotine induced Akt degradation via UPS, and Akt overexpression blocked nicotine-induced apoptosis in HUVECs cultured in HG/HF media. Furthermore, the TTC3 and MUL1 shRNA adenovirus dramatically decreased the Akt ubiquitination and apoptosis induced by nicotine. These results indicate that nicotine-induced Akt ubiquitination and degradation occurs through TTC3 and MUL1 and results in a dramatic increase in apoptosis in HUVECs cultured in HG/HF media.

Pleiotrophin, a target of miR-384, promotes proliferation, metastasis and lipogenesis in HBV-related hepatocellular carcinoma

Hepatitis B virus (HBV) infection plays a crucial role and is a major cause of hepatocellular carcinoma (HCC) in China. microRNAs (miRNAs) have emerged as key players in hepatic steatosis and carcinogenesis. We found that down-regulation of miR-384 expression was a common event in HCC, especially HBV-related HCC. However, the possible function of miR-384 in HBV-related HCC remains unclear. The oncogene pleiotrophin (PTN) was a target of miR-384. HBx inhibited miR-384, increasing PTN expression. The PTN receptor N-syndecan was highly expressed in HCC. PTN induced by HBx acted as a growth factor via N-syndecan on hepatocytes and further promoted cell proliferation, metastasis and lipogenesis. PTN up-regulated sterol regulatory element-binding protein 1c (SREBP-1c) through the N-syndecan/PI3K/Akt/mTORC1 pathway and the expression of lipogenic genes, including fatty acid synthesis (FAS). PTN-mediated de novo lipid synthesis played an important role in HCC proliferation and metastasis. PI3K/AKT and an mTORC1 inhibitor diminished PTN-induced proliferation, metastasis and lipogenesis. Taken together, these data strongly suggest that the dysregulation of miR-384 could play a crucial role in HBV related to HCC, and the target gene of miR-384, PTN, represents a new potential therapeutic target for the prevention of hepatic steatosis and further progression to HCC after chronic HBV infection.

Long non‑coding RNA HOTTIP promotes hepatocellular carcinoma tumorigenesis and development: A comprehensive investigation based on bioinformatics, qRT‑PCR and meta‑analysis of 393 cases

HOTTIP functions as an independent biomarker in multiple cancers. However, the role of HOTTIP in hepatocellular carcinoma (HCC) remains unclear. In this study, we sought to investigate the HOTTIP expression in HCC and normal liver. We combined quantitative reverse transcription-polymerase chain reactions (qRT-PCR), Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA), Multi Experiment Matrix (MEM) and Oncomine database to assess the clinical role and the potential molecular mechanism of HOTTIP in HCC. Furthermore, a meta-analysis was performed to evaluate the relationship between HOTTIP and HCC tumorigenesis and development. Additionally, bioinformatics analysis, which contained Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and network analysis, were applied to investigate the underlying functions, pathways and networks of the potential genes. HOTTIP was obviously upregulated in HCC. A statistically significant higher expression of HOTTIP was found in TNM (III +IV), age (≥60), sex (male), race (white) and cirrhosis (no) compared to the control groups (P<0.05). Furthermore, the meta-analysis of 393 cases from multiple centers indicated that HOTTIP had high diagnostic value in HCC. Additionally, according to GO and KEGG analyses, we found that the most strongly enriched functional terms were gland development, transcription factor activity and extrinsic to membrane. Also, the HOTTIP co-expressed genes were significantly related to PPAR signaling pathway. We speculate that HOTTIP might play a vital part in HCC via regulating various pathways, especially PPAR signaling pathway. However, the detailed mechanism should be confirmed by functional experiments.

Cellular metabolism of tumor-associated macrophages - functional impact and consequences

Macrophages are innate immune cells that play a role not only in host defense against infections, but also in the pathophysiology of autoimmune and autoinflammatory disorders, as well as cancer. An important feature of macrophages is their high plasticity, with high ability to adapt to environmental changes by adjusting their cellular metabolism and immunological phenotype. Macrophages are one of the most abundant innate immune cells within the tumor microenvironment that have been associated with tumor growth, metastasis, angiogenesis and poor prognosis. In the context of cancer, however, so far little is known about metabolic changes in macrophages, which have been shown to determine functional fate of the cells in other diseases. Here, we review the current knowledge regarding the cellular metabolism of tumor-associated macrophages (TAMs) and discuss its implications for cell function. Understanding the regulation of the cellular metabolism of TAMs may reveal novel therapeutic targets for treatment of malignancies.

CD147 expression was positively linked to aggressiveness and worse prognosis of gastric cancer: a meta and bioinformatics analysis

CD147 (also named as Basigin or EMMPRIN) might promote cancer invasion and metastasis by inducing MMP and VEGF synthesis in tumor microenvironment. We performed a systematic meta and bioinformatics analysis through multiple online databases up to March 14, 2017. Up-regulated CD147 expression was found in gastric cancer, compared with normal mucosa (p < 0.05). The male patients with gastric cancer showed higher CD147 expression than the female ones (p < 0.0001). CD147 expression was positively correlated with tumor size, depth of invasion, lymph node metastasis, TNM staging and unfavorable prognosis of gastric cancer (p < 0.05). At mRNA level, CD147 expression was higher in intestinal-type and mixed-type gastric carcinomas than normal tissues (p < 0.05). CD147 mRNA expression was negatively associated with histological grading and dedifferentiation of gastric cancer (p < 0.05). A higher CD147 mRNA expression was negatively correlated with overall and progression-free survival rates of all cancer patients, even stratified by clinicopathological features (p < 0.05). These findings indicated that CD147 expression might be employed as a potential marker to indicate gastric carcinogenesis and subsequent progression, even prognosis.