Loss of fatty acid synthase suppresses the malignant phenotype of colorectal cancer cells by down-regulating energy metabolism and mTOR signaling pathway

Epileptiform Discharges Reduce Neuronal ATP Production by Inhibiting F0F1-ATP Synthase Activity via A Zinc-α2-Glycoprotein-Dependent Mechanism

Neuronal energy metabolism dysfunction, especially adenosine triphosphate (ATP) supply decrease, is observed in epilepsy and associated with epileptogenesis and prognosis. Zinc-α2-glycoprotein (ZAG) is known as an important modulator of energy metabolism and involved in neuronal glucose metabolism, fatty acid metabolism, and ketogenesis impairment in seizures, but its effect on neuronal ATP synthesis in seizures and the specific mechanism are unclear. In this study, we verified the localization of ZAG in primary cultured neuronal mitochondria by using double-labeling immunofluorescence, immune electron microscopy, and western blot. ZAG level in neuronal mitochondria was modulated by lentiviruses and detected by western blot. The F0F1-ATP synthase activity, ATP level, and acetyl-CoA level were measured. The binding between ZAG and F0F1-ATP synthase was determined by coimmunoprecipitation. We found that both ZAG and F0F1-ATP synthase existed in neuronal mitochondria, and there was mutual binding between them. Epileptiform discharge-induced decrease of mitochondrial ZAG level was reversed by ZAG overexpression. Epileptiform discharge or ZAG knockdown decreased F0F1-ATP synthase activity and ATP level in neurons, which were reversed by ZAG overexpression, while overexpression of ZAG along only increased F0F1-ATP synthase activity but not increased ATP level. Meanwhile, neither epileptiform discharges nor changes of ZAG level can alter the acetyl-CoA level. Moreover, epileptiform discharge did not alter F0F1-ATP synthase level. In conclusion, epileptiform discharge-induced ZAG decrease in neuronal mitochondria is correlated to F0F1-ATP synthase activity inhibition, which may possibly lead to ATP supply impairments. ZAG may be a potential therapeutic target for treating neuronal energy metabolism dysfunction in seizures with further researches.

Brexpiprazole suppresses cell proliferation and de novo lipogenesis through AMPK/SREBP1 pathway in colorectal cancer

OBJECTIVE

In the present study, we investigated the role of brexpiprazole on cell proliferation and lipogenesis in colorectal cancer (CRC) and its molecular mechanism.

METHODS

The effect of brexpiprazole on CRC cell proliferation was determined by CCK-8, EdU assay, cell clone formation. The flow cytometry was evaluated cell cycle. Differential expression genes (DEGs) were identified by RNA-seq assay after treating HCT116 cells with or without 20 μM brexpiprazole for 24 h. Then, the top 120 DEGs were analyzed by GO and KEGG enrichment analysis. After that, Oil red O staining and the levels of total cholestenone and triglyceride were measured to assess lipogenesis capacity in CRC cells. The related molecules of cell proliferation, lipogenic and AMPK/SREBP1 signal pathways were measured by q-PCR, western blot and immunohistochemical staining.

RESULTS

Brexpiprazole remarkably suppressed cell proliferation, lipogenesis, and induced cell cycle arrest in CRC. The underlying mechanisms probably involved the suppression of SREBP1 and the stimulation of AMPK.

CONCLUSION

Brexpiprazole inhibited cell proliferation and de novo lipogenesis through AMPK/SREBP1 pathway in CRC.

Malonyl-CoA is a conserved endogenous ATP-competitive mTORC1 inhibitor

Cell growth is regulated by the mammalian/mechanistic target of rapamycin complex 1 (mTORC1), which functions both as a nutrient sensor and a master controller of virtually all biosynthetic pathways. This ensures that cells are metabolically active only when conditions are optimal for growth. Notably, although mTORC1 is known to regulate fatty acid biosynthesis, how and whether the cellular lipid biosynthetic capacity signals back to fine-tune mTORC1 activity remains poorly understood. Here we show that mTORC1 senses the capacity of a cell to synthesise fatty acids by detecting the levels of malonyl-CoA, an intermediate of this biosynthetic pathway. We find that, in both yeast and mammalian cells, this regulation is direct, with malonyl-CoA binding to the mTOR catalytic pocket and acting as a specific ATP-competitive inhibitor. When fatty acid synthase (FASN) is downregulated/inhibited, elevated malonyl-CoA levels are channelled to proximal mTOR molecules that form direct protein-protein interactions with acetyl-CoA carboxylase 1 (ACC1) and FASN. Our findings represent a conserved and unique homeostatic mechanism whereby impaired fatty acid biogenesis leads to reduced mTORC1 activity to coordinately link this metabolic pathway to the overall cellular biosynthetic output. Moreover, they reveal the existence of a physiological metabolite that directly inhibits the activity of a signalling kinase in mammalian cells by competing with ATP for binding.

DIS3L2 knockdown impairs key oncogenic properties of colorectal cancer cells via the mTOR signaling pathway

DIS3L2 degrades different types of RNAs in an exosome-independent manner including mRNAs and several types of non-coding RNAs. DIS3L2-mediated degradation is preceded by the addition of nontemplated uridines at the 3'end of its targets by the terminal uridylyl transferases 4 and 7. Most of the literature that concerns DIS3L2 characterizes its involvement in several RNA degradation pathways, however, there is some evidence that its dysregulated activity may contribute to cancer development. In the present study, we characterize the role of DIS3L2 in human colorectal cancer (CRC). Using the public RNA datasets from The Cancer Genome Atlas (TCGA), we found higher DIS3L2 mRNA levels in CRC tissues versus normal colonic samples as well as worse prognosis in patients with high DIS3L2 expression. In addition, our RNA deep-sequencing data revealed that knockdown (KD) of DIS3L2 induces a strong transcriptomic disturbance in SW480 CRC cells. Moreover, gene ontology (GO) analysis of significant upregulated transcripts displays enrichment in mRNAs encoding proteins involved in cell cycle regulation and cancer-related pathways, which guided us to evaluate which specific hallmarks of cancer are differentially regulated by DIS3L2. To do so, we employed four CRC cell lines (HCT116, SW480, Caco-2 and HT-29) differing in their mutational background and oncogenicity. We demonstrate that depletion of DIS3L2 results in reduced cell viability of highly oncogenic SW480 and HCT116 CRC cells, but had little or no impact in the more differentiated Caco-2 and HT-29 cells. Remarkably, the mTOR signaling pathway, crucial for cell survival and growth, is downregulated after DIS3L2 KD, whereas AZGP1, an mTOR pathway inhibitor, is upregulated. Furthermore, our results indicate that depletion of DIS3L2 disturbs metastasis-associated properties, such as cell migration and invasion, only in highly oncogenic CRC cells. Our work reveals for the first time a role for DIS3L2 in sustaining CRC cell proliferation and provides evidence that this ribonuclease is required to support the viability and invasive behavior of dedifferentiated CRC cells.

Overview of Cancer Metabolism and Signaling Transduction

Despite the remarkable progress in cancer treatment up to now, we are still far from conquering the disease. The most substantial change after the malignant transformation of normal cells into cancer cells is the alteration in their metabolism. Cancer cells reprogram their metabolism to support the elevated energy demand as well as the acquisition and maintenance of their malignancy, even in nutrient-poor environments. The metabolic alterations, even under aerobic conditions, such as the upregulation of the glucose uptake and glycolysis (the Warburg effect), increase the ROS (reactive oxygen species) and glutamine dependence, which are the prominent features of cancer metabolism. Among these metabolic alterations, high glutamine dependency has attracted serious attention in the cancer research community. In addition, the oncogenic signaling pathways of the well-known important genetic mutations play important regulatory roles, either directly or indirectly, in the central carbon metabolism. The identification of the convergent metabolic phenotypes is crucial to the targeting of cancer cells. In this review, we investigate the relationship between cancer metabolism and the signal transduction pathways, and we highlight the recent developments in anti-cancer therapy that target metabolism.

circCAPRIN1 interacts with STAT2 to promote tumor progression and lipid synthesis via upregulating ACC1 expression in colorectal cancer

BACKGROUND

Circular RNAs (circRNAs) generated by back-splicing of precursor mRNAs (pre-mRNAs) are often aberrantly expressed in cancer cells. Accumulating evidence has revealed that circRNAs play a critical role in the progression of several cancers, including colorectal cancer (CRC). However, the current understandings of the emerging functions of circRNAs in CRC lipid metabolism and the underlying molecular mechanisms are still limited. Here, we aimed to explore the role of circCAPRIN1 in regulating CRC lipid metabolism and tumorigenesis.

METHODS

circRNA microarray was performed with three pairs of tumor and non-tumor tissues from CRC patients. The expression of circRNAs were determined by quantitative PCR (qPCR) and in situ hybridization (ISH). The endogenous levels of circRNAs in CRC cells were manipulated by transfection with lentiviruses overexpressing or silencing circRNAs. The regulatory roles of circRNAs in the occurrence of CRC were investigated both in vitro and in vivo using gene expression array, RNA pull-down/mass spectrometry, RNA immunoprecipitation assay, luciferase reporter assay, chromatin immunoprecipitation analysis, and fluorescence in situ hybridization (FISH).

RESULTS

Among circRNAs, circCAPRIN1 was most significantly upregulated in CRC tissue specimens. circCAPRIN1 expression was positively correlated with the clinical stage and unfavorable prognosis of CRC patients. Downregulation of circCAPRIN1 suppressed proliferation, migration, and epithelial-mesenchymal transition of CRC cells, while circCAPRIN1 overexpression had opposite effects. RNA sequencing and gene ontology analysis indicated that circCAPRIN1 upregulated the expressions of genes involved in CRC lipid metabolism. Moreover, circCAPRIN1 promoted lipid synthesis by enhancing Acetyl-CoA carboxylase 1 (ACC1) expression. Further mechanistic assays demonstrated that circCAPRIN1 directly bound signal transducer and activator of transcription 2 (STAT2) to activate ACC1 transcription, thus regulating lipid metabolism and facilitating CRC tumorigenesis.

CONCLUSIONS

These findings revealed the oncogenic role and mechanism of circCAPRIN1 in CRC. circCAPRIN1 interacted with STAT2 to promote CRC tumor progression and lipid synthesis by enhancing the expression of ACC1. circCAPRIN1 may be considered as a novel potential diagnostic and therapeutic target for CRC patients.

Cerulenin suppresses ErbB2-overexpressing breast cancer by targeting ErbB2/PKM2 pathway

Cerulenin is a fungal metabolite and a specific inhibitor of fatty acid synthase (FASN), which has shown a potential anticancer activity. 20-25% of breast cancer patients with ErbB2-overexpressing develop resistance to treatment. Therefore, it is urgent to find an effective new target for the treatment of ErbB2-overexpressing breast cancer. Our previous study found that cerulenin inhibits the glycolysis and migration of SK-BR-3 cells, but the effect of cerulenin on other malignant phenotypes of breast cancer is still unknown. Furthermore, the mechanism by which cerulenin displays its inhibitory effects is not fully understood. In this study, we systematically investigate the inhibitory effects of cerulenin on proliferation, migration, invasion and glycolysis of ErbB2-overexpressing breast cancer cells and its molecular mechanism. We found that cerulenin obviously suppresses the proliferation, migration, invasion as well as glycolysis. Through bioinformatic analyses, we found that PKM2 might be a target of cerulenin. In addition, ErbB2 and its signaling pathway upregulated PKM2 protein levels. Furthermore, we demonstrated that cerulenin downregulated the protein levels of ErbB2, PKM2 and EMT markers (MMP9, MMP2 and Snail2) in a dose- and time-dependent manner. Finally, the inhibitory of cerulenin on colony formation, migration, invasion and glycolysis, as well as protein levels of EMT markers were rescued by replenishing with PKM2. These findings illustrated that cerulenin inhibits proliferation, migration, invasion and glycolysis by targeting ErbB2/PKM2 pathway in ErbB2-overexpressing breast cancer cells.

Hypomethylated gene RAC3 induces cell proliferation and invasion by increasing FASN expression in endometrial cancer

BACKGROUND

Endometrial cancer (EC) is one of the most prevalent gynecological cancers with a 5-year survival rate of 20-60%. Feasible prognostic molecular biomarkers of EC are necessary for accurate prediction of EC prognosis.

METHODS

RAC3 is a member of the Rho GTPases. Public databases including Gene Expression Profiling Interactive Analysis (GEPIA2), Tumor Immune Estimation Resource (TIMER), LinkedOmics, Search Tool for the Retrieval of Interacting Genes/Proteins (STRING), TISIDB and cBioPortal were employed to analyze the differential expression, clinicopathologic characteristics, functional networks, immune cell infiltrates and genetic alteration of RAC3 in EC patients.

RESULTS

RAC3 expression was elevated in EC patients analyzed by TIMER and GEPIA. Overexpression of RAC3 was obviously correlated with clinical stage, histological type, histological grade and DNA hypomethylation. Patients with high RAC3 expression displayed poor overall survival. Functional enrichment analysis showed that RAC3 was involved in translational initiation, DNA replication and mRNA processing. RAC3 expression was negatively associated with infiltrating levels of B cells, CD8+ T cells, macrophages and dendritic cells in EC. Experiments in vitro showed that RAC3 was upregulated in EC tissues and cell lines, and RAC3 induced cell proliferation and invasion by increasing fatty acid synthase (FASN) expression.

CONCLUSION

High expression of RAC3iscorrelated with poor prognosis and low infiltration of immune cells in EC. RAC3 promotes cell proliferation and invasion via FASN. These results demonstrate thatRAC3 functions as an EC oncogene and reveal its underlying mechanism in EC progression, suggesting that RAC3 may serve as a potential therapeutic target in EC.

Targeting Energy Metabolism in Cancer Treatment

Cancer is the second most common cause of death worldwide after cardiovascular diseases. The development of molecular and biochemical techniques has expanded the knowledge of changes occurring in specific metabolic pathways of cancer cells. Increased aerobic glycolysis, the promotion of anaplerotic responses, and especially the dependence of cells on glutamine and fatty acid metabolism have become subjects of study. Despite many cancer treatment strategies, many patients with neoplastic diseases cannot be completely cured due to the development of resistance in cancer cells to currently used therapeutic approaches. It is now becoming a priority to develop new treatment strategies that are highly effective and have few side effects. In this review, we present the current knowledge of the enzymes involved in the different steps of glycolysis, the Krebs cycle, and the pentose phosphate pathway, and possible targeted therapies. The review also focuses on presenting the differences between cancer cells and normal cells in terms of metabolic phenotype. Knowledge of cancer cell metabolism is constantly evolving, and further research is needed to develop new strategies for anti-cancer therapies.

Molecular Targets in Precision Chemoprevention of Colorectal Cancer: An Update from Pre-Clinical to Clinical Trials

Colorectal cancer (CRC) is one of the leading causes of cancer deaths worldwide. The initiation and progression of CRC is a multi-step process that proceeds via precursor lesions to carcinoma, with each stage characterized by its distinct molecular and tissue microenvironment changes. Precursor lesions of CRC, aberrant crypt foci, and adenoma exhibit drastic changes in genetic, transcriptomic, and proteomic profiles compared to normal tissue. The identification of these changes is essential and provides further validation as an initiator or promoter of CRC and, more so, as lesion-specific druggable molecular targets for the precision chemoprevention of CRC. Mutated/dysregulated signaling (adenomatous polyposis coli, β-catenin, epidermal growth factor receptor, V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS), tumor protein53, Akt, etc.), inflammatory (cyclooxygenase-2, microsomal prostaglandin E synthase-1, inducible nitric oxide synthase, and other pro-inflammatory mediators), and metabolic/growth factor (fatty acid synthase, β-Hydroxy β-methylglutaryl-CoA reductase, and ornithine decarboxylase) related targets are some of the well-characterized molecular targets in the precision chemoprevention of CRC. In this review, we discuss precursor-lesion specific targets of CRC and the current status of pre-clinical studies regarding clinical interventions and combinations for better efficacy and safety toward future precision clinical chemoprevention. In addition, we provide a brief discussion on the usefulness of secondary precision chemopreventive targets for tertiary precision chemoprevention to improve the disease-free and overall survival of advanced stage CRC patients.

Fatty Acid Synthase: An Emerging Target in Cancer

In recent years, lipid metabolism has garnered significant attention as it provides the necessary building blocks required to sustain tumor growth and serves as an alternative fuel source for ATP generation. Fatty acid synthase (FASN) functions as a central regulator of lipid metabolism and plays a critical role in the growth and survival of tumors with lipogenic phenotypes. Accumulating evidence has shown that it is capable of rewiring tumor cells for greater energy flexibility to attain their high energy requirements. This multi-enzyme protein is capable of modulating the function of subcellular organelles for optimal function under different conditions. Apart from lipid metabolism, FASN has functional roles in other cellular processes such as glycolysis and amino acid metabolism. These pivotal roles of FASN in lipid metabolism make it an attractive target in the clinic with several new inhibitors currently being tested in early clinical trials. This article aims to present the current evidence on the emergence of FASN as a target in human malignancies.

Therapeutic effects of Aconiti Lateralis Radix Praeparata combined with Zingiberis Rhizoma on doxorubicin-induced chronic heart failure in rats based on an integrated approach

OBJECTIVES

This study was aimed to explore the mechanism of Aconiti Lateralis Radix Praeparata (ALRP) and Zingiberis Rhizoma (ZR) on doxorubicin (DOX)-induced chronic heart failure (CHF) in rats by integrated approaches.

METHODS

Effects of ALRP and ZR on cardiac function, serum biochemical indicators and histopathology in rats were analysed. Moreover, UHPLC-Q-TOF/MS was performed to identify the potential metabolites affecting the pathological process of CHF. Metabolomics and network pharmacology analyses were conducted to illustrate the possible pathways and network in CHF treatment. The predicted gene expression levels in heart tissue were verified and assessed by RT-PCR.

KEY FINDINGS

ALRP-ZR demonstrated remarkable promotion of hemodynamic indices and alleviated histological damage of heart tissue. Metabolomics analyses showed that the therapeutic effect of ALRP and ZR is mainly associated with the regulation of eight metabolites and ten pathways, which may be responsible for the therapeutic efficacy of ALRP-ZR. Moreover, the results of RT-PCR showed that ALRP-ZR could substantially increase the expression level of energy metabolism-related genes, including PPARδ, PPARγ, Lpl, Scd, Fasn and Pla2g2e.

CONCLUSIONS

The results highlighted the role of ALRP-ZR in the treatment of CHF by influencing the metabolites related to energy metabolism pathway via metabolomics and network pharmacology analyses.

MicroRNA-195 Functions as a Tumor Suppressor by Directly Targeting Fatty Acid Synthase in Malignant Meningioma

OBJECTIVE

Meningiomas are among the most common primary intracranial tumors. Up to 20% of cases will show increased malignancy at histological examination (World Health Organization grade II or III). Effective pharmacotherapy, except for radiotherapy, is lacking. Therefore, it is necessary to study the pathogenesis of malignant meningioma to provide more treatment strategies.

METHODS

RNA sequencing and micro-RNA (miRNA) microarray detection were applied to identify differentially expressed messenger RNAs (mRNAs) and miRNAs in benign and malignant meningioma. The miRDB and TargetScan databases were used to predict the potential interaction between miRNAs and mRNAs. A proliferation assay was used to evaluate the cell growth. A wound healing assay and Transwell assay were performed to assess the cell migration and invasion abilities, respectively. The interaction between miRNA and mRNA was identified using a luciferase reporter assay.

RESULTS

We found fatty acid synthase (FASN) was significantly upregulated in malignant meningioma compared with benign meningioma. Knockdown of FASN significantly inhibited proliferation, migration, and invasion of IOMM-Lee cells. Moreover, miR-195 was verified to directly target FASN using a luciferase reporter assay. Upregulation of miR-195 also significantly inhibited proliferation, migration, and invasion of IOMM-Lee cells. Furthermore, we performed bioinformatics analysis to predict the competing endogenous RNAs (ceRNAs) and found that NUP210, SPIRE2, SLC7A1, and DMTN might function as ceRNAs of FASN by sponging miR-195 in meningioma.

CONCLUSIONS

Our results have suggested a tumor suppressive role for miR-195 in the tumorigenesis and progression of malignant meningioma by targeting FASN. In addition, NUP210, SPIRE2, SLC7A1, and DMTN might act as ceRNAs to regulate FASN expression by sponging miR-195.

Overexpression of the zinc-α2-glycoprotein accelerates apoptosis and inhibits growth via the mTOR/PTEN signaling pathway in gastric carcinoma cells

Adipocytokine alpha-2-glycoprotein 1 (AZGP1) is a 41-kDa protein which regulates insulin sensitivity and glycolipid metabolism. Recently, mounting evidence has indicated that AZGP1 plays a vital role in the progression and prognosis of many types of tumors, including hepatocellular carcinoma. Also, previous research has reported that AZGP1 levels are reduced significantly in patients with gastric carcinoma (GC). Here, we aim to assess the potential role and molecular mechanism underlying AZGP1-mediated regulation of GC progression. Both RT-PCR and Western blot methods demonstrated that AZGP1 levels were decreased in all GC cell lines tested, which included AGS, NCI-N87, MKN-28, SGC-7901 and MKN-45, relative to the normal human gastric mucosa epithelial (GES-1) cell line. Cell survival and proliferation rates were correspondingly were reduced, while cell apoptosis and caspase-3 activity were increased in NCI-N87 and SGC-7901 cells with high levels of AZGP1. Additionally, the mTOR signaling pathway was suppressed, whereas PTEN expression was elevated following transfection of NCI-N87 and SGC-7901 cells with an AZGP1 overexpressing plasmid. PTEN inhibition reversed the effects of AZGP1 on cell growth and apoptosis in SGC-7901 cells. Therefore, we conclude that AZGP1 induced apoptosis and growth inhibition in GC cells via the regulation of the mTOR/PTEN signaling pathway.

Zinc-α2-glycoprotein 1 promotes EMT in colorectal cancer by filamin A mediated focal adhesion pathway

Liver metastasis is the main reason for the poor prognosis of colorectal cancer, and identifying molecules involved in liver metastases of colorectal cancer may provide effective therapeutic targets. Zinc-α2-glycoprotein 1(AZGP1) is a candidate biomarker for diagnosis and prognosis in cancer. However, its function and molecular mechanism in metastatic colorectal cancer remains largely unknown. We previously found that up-regulated AZGP1 promotes proliferation, migration and invasion in colorectal cancer cell line, here we elucidated the mechanism of AZGP1 in regulating metastasis. In this article, we found that AZGP1 was also highly expressed in colorectal cancer tissues with liver metastasis relative to those without metastasis, and abundant expression of AZGP1 was associated with poor prognosis, also, AZGP1 down regulation prevented cell metastasis in vivo and in vitro. We further demonstrated that AZGP1 promotes metastasis by regulating the epithelial-mesenchymal transition (EMT) and associating with molecules involved in the focal adhesion pathway, including the adhesion molecule FLNA, which acts as an important protein interactor. More importantly, AZGP1 down regulation inhibited the phosphorylation of FLNA mediated by the restrain of PAK2 kinase, thereby inducing its proteolysis and subsequently affecting its subcellular localization, where it regulates the EMT and promotes metastasis. Collectively, these results highlight AZGP1 as a new and promising therapeutic molecule for liver metastatic colorectal cancer.

Inhibition of FASN suppresses the malignant biological behavior of non-small cell lung cancer cells via deregulating glucose metabolism and AKT/ERK pathway

Background

Fatty acid synthase (FASN) is overexpressed in most human carcinomas, including non-small cell lung cancer (NSCLC), and contributes to poor prognosis. An increasing number of studies have highlighted the potential function of FASN as both a biomarker and therapeutic target for cancers. However, the underlying molecular mechanisms of FASN in glucose metabolism and the malignant biological behavior of NSCLC remain the subjects of intensive investigation.

Methods

FASN expression was depleted by FASN-siRNA in A549 and NCI-H1299 cell lines to detect the function of glucose metabolism and the malignant biological behavior of NSCLC cells. Western-blot and qPCR were applied to determine the expressions of FASN, t-AKT, p-AKT, t-ERK, p-ERK, PKM2, HK2 and AZGP1. ATP and lactate were detected to determine the activation of glucose metabolism. CCK8 and transwell assays were used to detect the proliferation, invasion, and migration capacity of the two types of NSCLC cells. The xenograft mouse model was used to evaluate tumor weights after suppression of FASN.

Results

LV-FASN-siRNA and its control lentiviral vector were successfully transfected into the two types of NSCLC cells (A549 and NCI-H1299). LV-FASN siRNA significantly suppressed FASN expression in both NSCLC cell types, and expressions of p-AKT, p-ERK, PKM2, and AZGP1 were also significantly decreased. Notably, the levels of ATP and lactate were significantly decreased after transfection with LV-FASN siRNA. The proliferation of both NSCLC cell types was decreased after suppression of FASN. The invasion and migration capacity of A549, but not NCI-H1299, were inhibited following down-regulation of FASN. In vivo, inhibition of FASN caused a marked animal tumor weight loss.

Conclusions

FASN was involved in glucose metabolism via down-regulation of the AKT/ERK pathway and eventually altered the malignant phenotype in lung cancer cells.

Fatty acid synthase enhances colorectal cancer cell proliferation and metastasis via regulating AMPK/mTOR pathway

Objective: In the present study, we aimed to investigate the potential role of fatty acid synthase (FASN) in the development and progression of colorectal cancer (CRC). Materials and methods: FASN levels were analyzed in human CRC tissues and adjacent normal tissues by Western blots and immunohistochemistry. Potential roles of FASN in regulating CRC cell proliferation and migration were examined by genetic manipulation in vitro. The molecular signaling was determined to understand the mechanisms of observed FASN effects. Results: FASN level was upregulated in CRC tissues and high expression of FASN was significantly associated with lymph node metastasis, TNM (Tumor, Node, Metastases) stage and poor prognosis in patients with CRC. Knockdown of FASN attenuated CRC cell proliferation and migration in vitro while FASN overexpression possessed the opposite effects. FASN regulated AMP-activated protein kinase (AMPK)/mechanistic target of rapamycin (mTOR) pathway in CRC cells. Conclusion: FASN enhanced CRC cell proliferation and metastasis potentially through AMPK/mTOR pathway, indicating that FASN/AMPK/mTOR signaling axis may serve as a potential target for the treatment of CRC.

Changes in lipids composition and metabolism in colorectal cancer: a review

Altered metabolism of lipids is currently considered a hallmark characteristic of many malignancies, including colorectal cancer (CRC). Lipids are a large group of metabolites that differ in terms of their fatty acid composition. This review summarizes recent evidence, documenting many alterations in the content and composition of fatty acids, polar lipids, oxylipins and triacylglycerols in CRC patients' sera, tumor tissues and adipose tissue. Some of altered lipid molecules may be potential biomarkers of CRC risk, development and progression. Owing to a significant role of many lipids in cancer cell metabolism, some of lipid metabolism pathways may also constitute specific targets for anti-CRC therapy.

Small interfering RNA-mediated knockdown of fatty acid synthase attenuates the proliferation and metastasis of human gastric cancer cells via the mTOR/Gli1 signaling pathway

Fatty acid synthase (FASN), the main enzyme involved in de novo lipogenesis, is overexpressed in several types of tumor tissues. In addition, it is associated with tumor cell proliferation, metastasis, epithelial-mesenchymal transition (EMT) and a poor prognosis. However, the precise functions and internal mechanisms of FASN with regard to the proliferation, metastasis and EMT in gastric cancer (GC) cells remain elusive. The present study investigated FASN protein expression in 18 randomly selected pairs of GC tumors and matched normal tissues by western blot analysis. FASN-specific small interfering RNA (siRNA) was then transfected into SGC-7901 cells to examine the effect of FASN on proliferation and migration in vitro. Western blotting was used to detect the protein expression of FASN, EMT-related markers and key signaling molecules of the mechanistic target of rapamycin/zinc finger protein GLI1 (mTOR/Gli1) pathway. Reverse transcription-quantitative polymerase chain reaction was conducted to detect the mRNA expression of FASN and EMT-related markers. The FASN level was higher in the GC tissues compared with that in the surrounding normal tissues. Knockdown of FASN suppressed GC cell proliferation and metastasis in vitro. The silencing of FASN expression using siRNA reversed EMT at the protein and mRNA levels and decreased the expression of Gli1 via regulation of AMP-activated protein kinase/mTOR and protein kinase B/mTOR signaling in GC cells. Inhibition of FASN suppresses GC proliferation and metastasis through targeting of the mTOR/Gli1 signaling pathway, indicating that it may serve as a potential target for the treatment of GC.

AZGP1 inhibits soft tissue sarcoma cells invasion and migration

Background

One of the major challenges in soft tissue sarcomas is to identify factors that predict metastasis. AZGP1 is a potential biomarker of cancer progression, but its value in soft tissue sarcomas remains unknown. The aim of this study is to determine the expression level of AZGP1 in soft tissue sarcomas, and to analyze its influence on tumor progression.

Methods

AZGP1 immunohistochemistry (IHC) and RT-PCR were performed in 86 patients with soft tissue sarcomas. The relationships between AZGP1 levels and clinicopathologic features were analyzed. In vitro experiments were performed using fibrosarcoma (HT1080), rhabdomyosarcoma (RD) and synovial sarcoma (SW982) cell lines to corroborate our findings. We used lentiviral over-expression and knockdown assays to examine how changes of AZGP1 expressions might affect cellular migration and invasion.

Results

The quantitative RT-PCR results showed that AZGP1 expression was negatively correlated with metastasis and overall survival in soft tissue sarcomas (p < 0.05). Immunohistochemical staining showed lower expression of AZGP1 in patients with metastasis than in those without. Kaplan-Meier survival analysis showed that patients with low expression of AZGP1 had shorter overall (p = 0.056) and metastasis-free survivals (p = 0.038). These findings were corroborated by our in vitro experiments. Over-expression of AZGP1 significantly decreased RD cellular migration and invasion by 64% and 78%, respectively. HT1080 cells migration was inhibited by 2-fold, whereas their invasion was repressed by 7-fold after AZGP1 knockdown.

Conclusions

Our study reveals that reduced AZGP1 expression correlates with in vitro cellular migration and invasion. In vivo, it is associated with higher metastatic risk and shorter survival in patients with soft tissue sarcomas.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3962-5) contains supplementary material, which is available to authorized users.

MACC1 decreases the chemosensitivity of gastric cancer cells to oxaliplatin by regulating FASN expression

The effect of chemotherapeutic agents is limited as a result of drug resistance, which demands prompt solutions provided by clinical studies. To date, the underlying mechanisms of chemotherapy resistance are relatively unknown. Metastasis-associated in colon cancer 1 (MACC1) is an oncogene associated with the progression and prognosis of gastric cancer (GC). Bioinformatic analysis revealed that MACC1 is positively associated with fatty acid synthase (FASN), a major enzyme of lipogenesis, and drives chemoresistance to oxaliplatin in GC. Similar findings were demonstrated in two GC cell lines (BGC-823 and MKN-28) with MACC1 ectopic expression. We next employed FASN inhibitor C75 or siFASN (small interfering RNA targeted to FASN) to block endogenous fatty acid metabolism and it was revealed that cell proliferation and chemoresistance to oxaliplatin induced by MACC1 upregulation were attenuated by FASN blockade to various extents. Conclusively, these outcomes highlight a novel role of MACC1 in GC cell lipogenesis, and suggest that MACC1 may be an attractive target to decrease oxaliplatin resistance in GC.

Deciphering the Roles of Thiazolidinediones and PPAR in Bladder Cancer

The use of thiazolidinedione (TZD) therapy in type II diabetic patients has proven useful in the lowering of blood glucose levels. However, recent investigations have shown that there may be potential health concerns associated, including the risk of developing bladder cancer as well as complications in the cardiovasculature. TZDs are ligands for the nuclear receptor PPARγ, and activation causes lipid uptake and insulin sensitization, both of which are critical processes for diabetic patients whose bodies are unable to utilize insulin effectively. Several studies have shown that PPARγ/TZDs decrease IGF-1 levels and, thus, reduce cancer growth in carcinomas such as the pancreas, colon, liver, and prostate. However, other studies have shed light on the potential of the receptor as a biomarker for uroepithelial carcinomas, particularly due to its stimulatory effect on migration of bladder cancer cells. Furthermore, PPARγ may provide the tumor-promoting microenvironment by de novo synthesis of nutrients that are needed for bladder cancer development. In this review, we closely examine the TZD class of drugs and their effects on PPARγ in patient studies along with additional molecular factors that are positive modulators, such as protein phosphatase 5 (PP5), which may have considerable implications for bladder cancer therapy.

MicroRNA-1207-5p inhibits hepatocellular carcinoma cell growth and invasion through the fatty acid synthase-mediated Akt/mTOR signalling pathway

Fatty acid synthase (FASN) has emerged as a unique oncologic target for the treatment of cancers, including hepatocellular carcinoma (HCC). However, effective inhibitors of FASN for cancer treatment are lacking. MicroRNAs (miRNAs) have emerged as novel and endogenic inhibitors of gene expression. In the present study, we aimed to investigate the role of miR‑1207‑5p in HCC and the regulation of FASN through miR‑1207‑5p. The expression of miR-1207-5p was markedly reduced in HCC tissues and cell lines as detected with real‑time quantitative polymerase chain reaction (qPCR). Overexpression of miR-1207-5p significantly suppressed the cell growth and invasion of HCC cells. By contrast, inhibition of miR‑1207‑5p exhibited an opposite effect. Bioinformatics analysis showed that FASN is a predicted target of miR‑1207‑5p which was validated by dual‑luciferase reporter assay, qPCR and western blot analysis. Overexpression of miR‑1207‑5p inhibited the Akt/mTOR signalling pathway, and promotion of this pathway was noted following inhibition of miR‑1207‑5p. Rescue experiments showed that the restoration of FASN expression partially reversed the inhibitory effect of miR‑1207‑5p on cell growth, invasion and Akt phosphorylation. In conclusion, our study suggests that miR‑1207‑5p/FASN plays an important role in HCC, and provides novel insight into developing new inhibitors for FASN for therapeutic interventions for HCC.

How Diet Intervention via Modulation of DNA Damage Response through MicroRNAs May Have an Effect on Cancer Prevention and Aging, an in Silico Study

The DNA damage response (DDR) is a molecular mechanism that cells have evolved to sense DNA damage (DD) to promote DNA repair, or to lead to apoptosis, or cellular senescence if the damage is too extensive. Recent evidence indicates that microRNAs (miRs) play a critical role in the regulation of DDR. Dietary bioactive compounds through miRs may affect activity of numerous genes. Among the most studied bioactive compounds modulating expression of miRs are epi-gallocatechin-3-gallate, curcumin, resveratrol and n3-polyunsaturated fatty acids. To compare the impact of these dietary compounds on DD/DDR network modulation, we performed a literature search and an in silico analysis by the DIANA-mirPathv3 software. The in silico analysis allowed us to identify pathways shared by different miRs involved in DD/DDR vis-à-vis the specific compounds. The results demonstrate that certain miRs (e.g., -146, -21) play a central role in the interplay among DD/DDR and the bioactive compounds. Furthermore, some specific pathways, such as "fatty acids biosynthesis/metabolism", "extracellular matrix-receptor interaction" and "signaling regulating the pluripotency of stem cells", appear to be targeted by most miRs affected by the studied compounds. Since DD/DDR and these pathways are strongly related to aging and carcinogenesis, the present in silico results of our study suggest that monitoring the induction of specific miRs may provide the means to assess the antiaging and chemopreventive properties of particular dietary compounds.