Anoikis resistant mediated by FASN promoted growth and metastasis of osteosarcoma

Lipid metabolic reprogramming and associated ferroptosis in osteosarcoma: From molecular mechanisms to potential targets

Osteosarcoma is a common bone tumor in adolescents, which is characterized by lipid metabolism disorders and plays a key role in tumorigenesis and disease progression. Ferroptosis is an iron-dependent form of programmed cell death associated with lipid peroxidation. This review provides an in-depth analysis of the complex relationship between lipid metabolic reprogramming and associated ferroptosis in OS from the perspective of metabolic enzymes and metabolites. We discussed the molecular basis of lipid uptake, synthesis, storage, lipolysis, and the tumor microenvironment, as well as their significance in OS development. Key enzymes such as adenosine triphosphate-citrate lyase (ACLY), acetyl-CoA synthetase 2 (ACSS2), fatty acid synthase (FASN) and stearoyl-CoA desaturase-1 (SCD1) are overexpressed in OS and associated with poor prognosis. Based on specific changes in metabolic processes, this review highlights potential therapeutic targets in the lipid metabolism and ferroptosis pathways, and in particular the HMG-CoA reductase inhibitor simvastatin has shown potential in inducing apoptosis and inhibiting OS metastasis. Targeting these pathways provides new strategies for the treatment of OS. However, challenges such as the complexity of drug development and metabolic interactions must be overcome. A comprehensive understanding of the interplay between dysregulation of lipid metabolism and ferroptosis is essential for the development of innovative and effective therapies for OS, with the ultimate goal of improving patient outcomes.

Prediction and validation of anoikis-related genes in neuropathic pain using machine learning

BACKGROUND

Neuropathic pain (NP) can be induced by a variety of clinical conditions, such as spinal cord injury, lumbar disc herniation (LDH), lumbar spinal stenosis, diabetes, herpes zoster, and spinal cord tumors, and inflammatory stimuli. The pathogenesis of NP is extremely complex. Specifically, in LDH, the herniated nucleus pulposus exerts mechanical pressure on nerve roots, triggering local inflammation and consequent NP. Anoikis, a special form of programmed cell death, is closely related to the progression of NP. In this study, we sought to clarify the molecular characteristics of anoikis-related genes in NP, providing novel insights for the diagnosis and treatment of NP.

METHODS

We screened NP-related genes based on the GSE124272 dataset and obtained 439 anoikis-related genes from the GeneCards database. Through Least Absolute Shrinkage and Selection Operator (LASSO) and Support Vector Machine (SVM) machine learning algorithms, six key hub genes were identified: hepatocyte growth factor (HGF), matrix metalloproteinase 13 (MMP13), c-abl oncogene 1, non-receptor tyrosine kinase (ABL1), elastase neutrophil expressed (ELANE), fatty acid synthase (FASN), and long non-coding RNA (Linc00324). Functional enrichment analyses, including Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), alongside Gene Set Enrichment Analysis (GSEA) and immune infiltration analysis, were performed on these hub genes. Additionally, transcription factors and potential therapeutic drugs were predicted. We also used rats to construct an NP model and validated the analyzed hub genes using hematoxylin and eosin (H&E) staining, real-time polymerase chain reaction (PCR), and Western blotting assays.

RESULTS

Our data indicated that anoikis-related genes have diagnostic value in NP patients, as confirmed by experimental results. Moreover, this study elucidated the role of these genes in immune infiltration during the pathogenesis of NP and identified potential therapeutic drugs targeting these key genes.

CONCLUSION

This study further explores the pathogenesis of NP and provides certain reference value for developing targeted therapeutic strategies, thereby improving NP management.

Identification of a novel signature based on RNA methylation-associated anoikis-related genes for predicting prognosis and characterizing immune landscape in colorectal cancer

BACKGROUND

RNA methylation is a potential target for cancer therapy, while anoikis, a form of programmed cell death, is linked to cancer metastasis. However, the prognostic and immune significance of RNA methylation- and anoikis-related genes in colorectal cancer (CRC) remains unknown.

METHODS

Transcriptomic and clinicopathological data for CRC were obtained from TCGA and the GEO databases. A novel signature was constructed based on RNA methylation- and anoikis-related genes using univariate and multivariate Cox regression as well as LASSO Cox regression methods. CRC patients were stratified into low- and high-risk groups based on this signature. Differences in prognosis, immune infiltration, and drug sensitivity between two groups were analyzed. Finally, immunohistochemistry, western blot, and RT-qPCR were employed to validate the expression of the key gene SERPINE1 in CRC tissues and cells, as well as the effect of FTO on its expression.

RESULTS

We identified 79 differentially expressed RNA methylation-associated anoikis-related genes (RMRARGs) in both cancerous and normal tissues. A signature composed of 9 key genes (BID, FASN, PLK1, CDKN3, MYC, EPHA2, SERPINE1, CD36, PDK4) was established. Kaplan-Meier analysis revealed a poorer prognosis in the high-risk group. Compared to the other three published models, this signature demonstrated superior predictive performance based on the ROC curve analysis. Functional analyses highlighted differences in drug sensitivities and signaling pathways between risk groups. Furthermore, immune analysis results showed that risk score was associated with some immune cells and immune checkpoints. Immunohistochemistry showed high SERPINE1 expression in CRC tissues, with FTO expression positively correlated with SERPINE1. Furthermore, RT-qPCR and western blot indicated FTO knockdown markedly downregulated SERPINE1 levels.

CONCLUSION

Our findings underscore the prognostic value of this signature in CRC patients and its utility in assessing immune status. Additionally, the m6A demethylase FTO regulates the expression of the anoikis-related gene SERPINE1.

SPICE1 promotes osteosarcoma growth by enhancing the deubiquitination of FASN mediated by USP10

BACKGROUND

Osteosarcoma (OS) is recognized as a prevalent primary bone malignancy, particularly affecting adolescents during their growth spurts. Despite its clinical significance, the underlying biological characteristics and associated prognostic factors remain incompletely understood. The identification of novel molecular players involved in osteosarcoma progression could enhance our understanding of its pathogenesis and potentially inform patient management strategies.

METHODS

In this study, we investigated the expression levels of Spindle and Centriole-Associated Protein 1 (SPICE1) in OS cells and tissues through quantitative analyses. We performed in vitro and in vivo experiments to evaluate the proliferation effects of SPICE1 on OS cells. Additionally, we explored the mechanistic interactions between SPICE1, Fatty Acid Synthase (FASN), and ubiquitin-specific peptidase 10 (USP10) through co-immunoprecipitation and mutation analyses, including the design of a peptide to inhibit the SPICE1-FASN interaction.

RESULTS

Our findings revealed that SPICE1 is significantly overexpressed in OS samples. Furthermore, this high expression correlates with poor patient prognosis. The elevated levels of SPICE1 were found to promote OS cell proliferation by inhibiting the ubiquitination of FASN, consequently enhancing FASN protein stability. Additionally, SPICE1 was shown to facilitate the interaction between USP10 and FASN, promoting FASN deubiquitination, with specific amino acid interactions identified between USP10 and FASN that are necessary for this process.

CONCLUSION

This study elucidates the role of SPICE1 as a potential oncogene in OS, highlighting its contribution to tumor growth through the modulation of FASN stability. Importantly, our results suggest that targeting the SPICE1/USP10/FASN signaling axis could offer a novel therapeutic approach for treating OS. Future investigations should focus on the development of specific inhibitors that disrupt this pathway, ultimately leading to improved clinical outcomes for patients with OS.

AURKB affects the proliferation of clear cell renal cell carcinoma by regulating fatty acid metabolism

BACKGROUND

Clear cell renal cell carcinoma (ccRCC) is the most common subtype of kidney cancer with a high metastatic rate and high mortality rate. The molecular mechanism of ccRCC development, however, needs further study. Aurora kinase B (AURKB) functions as an important oncogene in various tumors; therefore, in the present study, we aimed to explore the mechanism by which AURKB affects ccRCC development.

METHODS

We performed bioinformatics analysis, CCK-8 assay, RNA sequencing, RT-PCR and Western blot to analyze the function and mechanism of AURKB in ccRCC.

RESULTS

TIMER2.0 showed that AURKB was overexpressed in Kidney Renal Clear Cell Carcinoma (KIRC), the UALCAN database showed the survival rate of KIRC patients with different expression levels of AURKB and different gender indicated in the same gender, high AURKB expression predicts lower survival rate. Silencing of AURKB expression inhibits the proliferation of ccRCC cells. RNA-seq data suggested that AURKB is involved in fatty acid metabolism. Silencing of AURKB inhibited the expression of fatty acid synthase (FASN). FASN is a key gene involved in fatty acid metabolism. TIMER2.0 showed that FASN is upregulated in KIRC. Silencing of FASN inhibited the proliferation of ccRCC cells.

CONCLUSIONS

AURKB induces the proliferation of ccRCC cells by regulating fatty acid metabolism.

FASN inhibition shows the potential for enhancing radiotherapy outcomes by targeting glycolysis, AKT, and ERK pathways in breast cancer

PURPOSE

Breast cancer ranks as the most prevalent cancer in women, characterized by heightened fatty acid synthesis and glycolytic activity. Fatty acid synthase (FASN) is prominently expressed in breast cancer cells, regulating fatty acid synthesis, thereby enhancing tumor growth and migration, and leading to radioresistance. This study aims to investigate how FASN inhibition affects cell proliferation, migration, and radioresistance in breast cancer, as well as the mechanisms involved.

MATERIALS AND METHODS

We used lentiviruses carrying shFASN to create FASN-knockdown cell lines called MCF-7-shFASN and MDA-MB-231-shFASN. We conducted Western blot analysis to determine the expression levels of FASN and other proteins of interest. Furthermore, we evaluated cellular glucose uptake and migration using the 18F-FDG assay, wound healing, and transwell assays. We also employed the MTT assay to assess the short-term survival of the negative control and FASN-knockdown cells after irradiation.

RESULTS

FASN knockdown led to a decrease in the expressions of proteins related to fatty acid synthesis and glycolysis in both MCF-7-shFASN and MDA-MB-231-shFASN cells when compared to their counterparts. Moreover, reduced 18F-FDG uptake and lactate production were also detected after FASN knockdown. FASN knockdown inhibited cell proliferation and survival by downregulating the AKT, ERK, and AMPK pathways and promoted apoptosis by increasing the BAX/p-Bcl-2 ratio. In addition, FASN knockdown impaired cell migration while enhancing radiosensitivity.

CONCLUSIONS

FASN knockdown disrupts fatty acid synthesis and glycolysis, inhibits cell proliferation and induces apoptosis. The increased radiosensitivity after FASN inhibition suggests that it could potentially complement radiotherapy in treating breast cancer.

Identification of Anoikis-related potential biomarkers and therapeutic drugs in chronic thromboembolic pulmonary hypertension via bioinformatics analysis and in vitro experiment

There is growing evidence that programmed cell death plays a significant role in the pathogenesis of chronic thromboembolic pulmonary hypertension (CTEPH). Anoikis is a newly discovered type of programmed death and has garnered great attention. However, the precise involvement of Anoikis in the progression of CTEPH remains poorly understood. The goal of this study was to identify Anoikis-related genes (ARGs) and explore potential therapeutic drugs for CTEPH. Differentially expressed genes were identified by limma and weighted gene co-expression network analysis (WGCNA) packages, and functional analyses were conducted based on the differentially expressed genes. Subsequently, a combination of protein-protein interaction (PPI), Least Absolute Shrinkage and Selection Operator (LASSO), and Support Vector Machine Recursive Feature Elimination (SVM-RFE) methodologies was employed to screen hub genes associated with CTEPH, which were further verified by dataset GSE188938, quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. CIBERSORT was utilized to evaluate the infiltration of immune cells and the relationship between infiltration-related immune cells and ARGs. Finally, targeted drug analysis and molecular docking were used to predict drugs targeting Anoikis process to treat CTEPH. Thirty-two differentially expressed genes related to Anoikis and CTEPH were screened through WGCNA analysis. Then, the key ARGs FASN, PLAUR, BCL2L1, HMOX1 and RHOB were screened by PPI, Lasso and SVM-RFE machine learning. Validation through dataset GSE188938, qRT-PCR, and Western blot analyses confirmed HMOX1 and PLAUR as powerful and promising biomarkers in CTEPH. In addition, CIBERSORT immunoinfiltration revealed that Mast_cells_activated and Neutrophils were involved in the pathological regulation of CTEPH. Correlation analysis indicated that HMOX1 was positively correlated with Neutrophils, while PLAUR was negatively correlated with Mast_cells_activated. Finally we used targeted drug analysis and molecular docking to identify that STANNSOPORFIN as a potential drug targeting HMOX1 for the treatment of CTEPH. HMOX1 and PLAUR emerge as potential biomarkers for CTEPH and may influence the development of CTEPH by regulating Anoikis. Mast_cells_activated and Neutrophils may be involved in Anoikis resistance in CTEPH patients, presenting novel insights into CTEPH therapeutic targets. STANNSOPORFIN is a potential agents targeting Anoikis process therapy for CTEPH.

FASN promotes anoikis resistance in colorectal liver metastases through the ERK1/2 pathway

PURPOSE

Colorectal cancer (CRC) is recognized as the third most common form of malignancy, with the liver frequently serving as the main site for metastasis. Anoikis resistance (AR) is critical in colorectal cancer liver metastases (CRLM). Fatty acid synthase (FASN), essential in lipid synthesis, mediates AR in many cancers. The present research examines the function of FASN in ERK1/2-mediated AR in CRLM and evaluates its therapeutic potential.

METHODS

We performed scratch and migration experiment to evaluate the migration capacity of the LoVo cells. Flow cytometry was employed to identify cell apoptosis. The levels of FASN, p-ERK1/2, and proteins related to apoptosis was analyzed by Western blot. The mRNA level of FASN was determined by q-PCR after FASN silencing. In addition, we used an intrasplenic liver metastasis model of nude to assess the effect of FASN on CRLM.

RESULTS

In vitro experiments showed that after FASN silencing, the cell apoptosis rate was increased, migration capability was notably decreased, the expression of p-ERK1/2, the proteins related to anti-apoptotic were significantly decreased, and the proteins related to apoptosis were significantly increased. In vivo experiments showed that AR significantly increased the number of liver metastatic foci, whereas FASN silencing significantly inhibited CRLM.

CONCLUSION

These results suggest that FASN silencing suppressed AR through the ERK 1/2 pathway, which in turn suppressed CRLM.

FOSL1 promotes stem cell‑like characteristics and anoikis resistance to facilitate tumorigenesis and metastasis in osteosarcoma by targeting SOX2

Metastasis is the leading cause of cancer‑related death in osteosarcoma (OS). OS stem cells (OSCs) and anoikis resistance are considered to be essential for tumor metastasis formation. However, the underlying mechanisms involved in the maintenance of a stem‑cell phenotype and anoikis resistance in OS are mostly unknown. Fos‑like antigen 1 (FOSL1) is important in maintaining a stem‑like phenotype in various cancers; however, its role in OSCs and anoikis resistance remains unclear. In the present study, the dynamic expression patterns of FOSL1 were investigated during the acquisition of cancer stem‑like properties using RNA sequencing, PCR, western blotting and immunofluorescence. Flow cytometry, tumor‑sphere formation, clone formation assays, anoikis assays, western blotting and in vivo xenograft and metastasis models were used to further investigate the responses of the stem‑cell phenotype and anoikis resistance to FOSL1 overexpression or silencing in OS cell lines. The underlying molecular mechanisms were evaluated, focusing on whether SOX2 is crucially involved in FOSL1‑mediated stemness and anoikis in OS. FOSL1 expression was observed to be upregulated in OSCs and promoted tumor‑sphere formation, clone formation and tumorigenesis in OS cells. FOSL1 expression correlated positively with the expression of stemness‑related factors (SOX2, NANOG, CD117 and Stro1). Moreover, FOSL1 facilitated OS cell anoikis resistance and promoted metastases by regulating the expression of apoptosis related proteins BCL2 and BAX. Mechanistically, FOSL1 upregulated SOX2 expression by interacting with the SOX2 promoter and activating its transcription. The results also showed that SOX2 is critical for FOSL1‑mediated stem‑like properties and anoikis resistance. The current findings indicated that FOSL1 is an important regulator that promotes a stem cell‑like phenotype and anoikis resistance to facilitate tumorigenesis and metastasis in OS by regulating the transcription of SOX2. Thus, FOSL1 might represent an attractive target for therapeutic interventions in OS.

Prognostic analysis of anoikis-related genes in bladder cancer: An observational study

Anoikis is proved to play a crucial role in the development of cancers. However, the impact of anoikis on the prognosis of bladder cancer (BLCA) is currently unknown. Thus, this study aimed to find potential effect of anoikis in BLCA. The Cancer Genome Atlas (TCGA)-BLCA and GSE13507 cohorts were downloaded from TCGA and the Gene Expression Omnibus (GEO) databases, respectively. Differentially expressed genes (DEGs) were screened between BLCA and normal groups, which intersected with anoikis-related genes to yield anoikis-related DEGs (AR DEGs). Univariate COX, rbsurv, and multivariate COX analyses were adopted in order to build a prognostic risk model. The differences of risk score in the different clinical subgroups and the relevance between survival rate and clinical characteristics were explored as well. Finally, chemotherapy drug sensitivity in different risk groups was analyzed. In total, 78 AR DEGs were acquired and a prognostic signature was build based on the 6 characteristic genes (CALR, FASN, CSPG4, HGF, INHBB, SATB1), where the patients of low-risk group had longer survival time. The survival rate of BLCA patients was significantly differential in different groups of age, stage, smoking history, pathologic-T, and pathologic-N. The IC50 of 56 drugs showed significant differences between 2 risk groups, such as imatinib, docetaxel, and dasatinib. At last, the results of real time quantitative-polymerase chain reaction (RT-qPCR) demonstrated that the expression trend of CALR, HGF, and INHBB was consistent with the result obtained previously based on public databases. Taken together, this study identified 6 anoikis-related characteristic genes (CALR, FASN, CSPG4, HGF, INHBB, SATB1) for the prognosis of BLCA patients, providing a scientific reference for further research on BLCA.

EDI3 knockdown in ER-HER2+ breast cancer cells reduces tumor burden and improves survival in two mouse models of experimental metastasis

BACKGROUND

Despite progress understanding the mechanisms underlying tumor spread, metastasis remains a clinical challenge. We identified the choline-producing glycerophosphodiesterase, EDI3 and reported its association with metastasis-free survival in endometrial cancer. We also observed that silencing EDI3 slowed cell migration and other cancer-relevant phenotypes in vitro. Recent work demonstrated high EDI3 expression in ER-HER2+ breast cancer compared to the other molecular subtypes. Silencing EDI3 in ER-HER2+ cells significantly reduced cell survival in vitro and decreased tumor growth in vivo. However, a role for EDI3 in tumor metastasis in this breast cancer subtype was not explored. Therefore, in the present work we investigate whether silencing EDI3 in ER-HER2+ breast cancer cell lines alters phenotypes linked to metastasis in vitro, and metastasis formation in vivo using mouse models of experimental metastasis.

METHODS

To inducibly silence EDI3, luciferase-expressing HCC1954 cells were transduced with lentiviral particles containing shRNA oligos targeting EDI3 under the control of doxycycline. The effect on cell migration, adhesion, colony formation and anoikis was determined in vitro, and significant findings were confirmed in a second ER-HER2+ cell line, SUM190PT. Doxycycline-induced HCC1954-luc shEDI3 cells were injected into the tail vein or peritoneum of immunodeficient mice to generate lung and peritoneal metastases, respectively and monitored using non-invasive bioluminescence imaging. Metabolite levels in cells and tumor tissue were analyzed using targeted mass spectrometry and MALDI mass spectrometry imaging (MALDI-MSI), respectively.

RESULTS

Inducibly silencing EDI3 reduced cell adhesion and colony formation, as well as increased susceptibility to anoikis in HCC1954-luc cells, which was confirmed in SUM190PT cells. No influence on cell migration was observed. Reduced luminescence was seen in lungs and peritoneum of mice injected with cells expressing less EDI3 after tail vein and intraperitoneal injection, respectively, indicative of reduced metastasis. Importantly, mice injected with EDI3-silenced cells survived longer. Closer analysis of the peritoneal organs revealed that silencing EDI3 had no effect on metastatic organotropism but instead reduced metastatic burden. Finally, metabolic analyses revealed significant changes in choline and glycerophospholipid metabolites in cells and in pancreatic metastases in vivo.

CONCLUSIONS

Reduced metastasis upon silencing supports EDI3's potential as a treatment target in metastasizing ER-HER2+ breast cancer.

Develop a Novel Signature to Predict the Survival and Affect the Immune Microenvironment of Osteosarcoma Patients: Anoikis-Related Genes

Objective

Osteosarcoma (OS) represents a prevalent primary bone neoplasm predominantly affecting the pediatric and adolescent populations, presenting a considerable challenge to human health. The objective of this investigation is to develop a prognostic model centered on anoikis-related genes (ARGs), with the aim of accurately forecasting the survival outcomes of individuals diagnosed with OS and offering insights into modulating the immune microenvironment.

Methods

The study's training cohort comprised 86 OS patients sourced from The Cancer Genome Atlas database, while the validation cohort consisted of 53 OS patients extracted from the Gene Expression Omnibus database. Differential analysis utilized the GSE33382 dataset, encompassing three normal samples and 84 OS samples. Subsequently, the study executed gene ontology and Kyoto encyclopedia of genes and genomes enrichment analyses. Identification of differentially expressed ARGs associated with OS prognosis was carried out through univariate COX regression analysis, followed by LASSO regression analysis to mitigate overfitting risks and construct a robust prognostic model. Model accuracy was assessed via risk curves, survival curves, receiver operating characteristic curves, independent prognostic analysis, principal component analysis, and t-distributed stochastic neighbor embedding (t-SNE) analysis. Additionally, a nomogram model was devised, exhibiting promising potential in predicting OS patient prognosis. Further investigations incorporated gene set enrichment analysis to delineate active pathways in high- and low-risk groups. Furthermore, the impact of the risk prognostic model on the immune microenvironment of OS was evaluated through tumor microenvironment analysis, single-sample gene set enrichment analysis (ssGSEA), and immune infiltration cell correlation analysis. Drug sensitivity analysis was conducted to identify potentially effective drugs for OS treatment. Ultimately, the verification of the implicated ARGs in the model construction was conducted through the utilization of real-time quantitative polymerase chain reaction (RT-qPCR).

Results

The ARGs risk prognostic model was developed, comprising seven high-risk ARGs (CBS, MYC, MMP3, CD36, SCD, COL13A1, and HSP90B1) and four low-risk ARGs (VASH1, TNFRSF1A, PIP5K1C, and CTNNBIP1). This prognostic model demonstrates a robust capability in predicting overall survival among patients. Analysis of immune correlations revealed that the high-risk group exhibited lower immune scores compared to the low-risk group within our prognostic model. Specifically, CD8+ T cells, neutrophils, and tumor-infiltrating lymphocytes were notably downregulated in the high-risk group, alongside significant downregulation of checkpoint and T cell coinhibition mechanisms. Additionally, three immune checkpoint-related genes (CD200R1, HAVCR2, and LAIR1) displayed significant differences between the high- and low-risk groups. The utilization of a nomogram model demonstrated significant efficacy in prognosticating the outcomes of OS patients. Furthermore, tumor metastasis emerged as an independent prognostic factor, suggesting a potential association between ARGs and OS metastasis. Notably, our study identified eight drugs-Bortezomib, Midostaurin, CHIR.99021, JNK.Inhibitor.VIII, Lenalidomide, Sunitinib, GDC0941, and GW.441756-as exhibiting sensitivity toward OS. The RT-qPCR findings indicate diminished expression levels of CBS, MYC, MMP3, and PIP5K1C within the context of OS. Conversely, elevated expression levels were observed for CD36, SCD, COL13A1, HSP90B1, VASH1, and CTNNBIP1 in OS.

Conclusion

The outcomes of this investigation present an opportunity to predict the survival outcomes among individuals diagnosed with OS. Furthermore, these findings hold promise for progressing research endeavors focused on prognostic evaluation and therapeutic interventions pertaining to this particular ailment.

Fatty acid synthase (FASN) signalome: A molecular guide for precision oncology

The initial excitement generated more than two decades ago by the discovery of drugs targeting fatty acid synthase (FASN)-catalyzed de novo lipogenesis for cancer therapy was short-lived. However, the advent of the first clinical-grade FASN inhibitor (TVB-2640; denifanstat), which is currently being studied in various phase II trials, and the exciting advances in understanding the FASN signalome are fueling a renewed interest in FASN-targeted strategies for the treatment and prevention of cancer. Here, we provide a detailed overview of how FASN can drive phenotypic plasticity and cell fate decisions, mitochondrial regulation of cell death, immune escape and organ-specific metastatic potential. We then present a variety of FASN-targeted therapeutic approaches that address the major challenges facing FASN therapy. These include limitations of current FASN inhibitors and the lack of precision tools to maximize the therapeutic potential of FASN inhibitors in the clinic. Rethinking the role of FASN as a signal transducer in cancer pathogenesis may provide molecularly driven strategies to optimize FASN as a long-awaited target for cancer therapeutics.

The anoikis-related gene signature predicts survival and correlates with immune infiltration in osteosarcoma

Anoikis is essential for the progression of many malignant tumors. However, the understanding of anoikis' roles in osteosarcoma remains scarce. This study conducted an extensive bioinformatics analysis to identify anoikis-related genes (ARGs), developed ARGs modeles for predicting OS and RFS, and evaluated the effect of these ARGs on osteosarcoma cell migration and invasion. The GSE16088 and GSE28425 datasets provided the differentially expressed genes (DEGs). The prognostic significance and functions of these DEGs were systematically investigated using several bioinformatics techniques. Transwell assays were conducted to determine the effect of OGT on osteosarcoma cell migration and invasion. Seven genes were identified as hub genes, including FN1, CD44, HRAS, TP53, PPARG, CTNNB1, and VEGFA, while 71 ARGs were identified as DEGs. Four ARGs-BRMS, COL4A2, FGF2, and OGT-were used to develop an RFS-predicting model, whereas seven ARGs-CD24, FASN, MMP2, EIF2AK3, ID2, PPARG, and PIK3R3-were used to develop an OS-predicting model in patients with osteosarcoma. In both the training and validation cohorts, high-risk group patients had significantly shorter OS and RFS duration than low-risk group patients. Furthermore, using the aforementioned ARGs, we developed clinically applicable nomograms for OS and RFS prediction. The proportion of tumor-infiltrating immune cells was significantly linked to risk scores. In vitro experiments revealed that knocking down OGT significantly inhibited the ability of MG63 and U2OS cells to invade and migrate. ARG-based gene signatures reliably predicted RFS and OS in osteosarcoma, and OGT showed promise as a potential biomarker. These findings contribute to a better understanding of ARGs' prognostic roles in osteosarcoma.

A novel anoikis-related gene signature predicts prognosis in patients with breast cancer and reveals immune infiltration

Breast cancer (BRCA) is a common malignancy worldwide that is associated with a high mortality rate. Despite recent improvements in diagnosis and treatment, there is an urgent need to investigate the processes underlying cancer progression and identify novel prognostic indicators. Anoikis, which plays a role in the development of human malignant tumors, has been gaining increasing interest from researchers. However, the potential role of anoikis-related genes (ANRGs) in the advancement of BRCA remains unknown. In this study, we aimed to assess the predictive value of ANRGs in BRCA, construct a prognostic model based on ANRGs, and explore the tumor microenvironment in different prognostic score groups. This study utilized data from the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases to collect clinical information and RNA sequencing data from patients with BRCA. Information on ANRGs was gathered from GeneCards and Harmonizome portals. A risk score model based on ANRGs was created using least absolute shrinkage and selection operator Cox (LASSO) regression analysis. Additionally, the study explored the tumor microenvironment and enriched pathways in different risk groups. Finally, a novel ANRG-based nomogram is developed. A total of 142 differentially expressed genes associated with survival were identified, of which 5 genes were selected to create the ANRG signature. The risk score based on this signature proved to be an independent prognostic factor. Further analysis revealed that different risk subgroups exhibited variations in the tumor microenvironment and drug sensitivities. Subsequently, a nomogram was developed using risk scores and clinicopathological factors. The decision curve analysis results suggest that patients with BRCA might derive clinical treatment benefits from utilizing this prognostic model. Based on the results of this study, the ANRG signature and nomograph established can be used for clinical decision-making in patients with BRCA.

Dissecting the role of lactate metabolism LncRNAs in the progression and immune microenvironment of osteosarcoma

BACKGROUND

The process of lactate metabolism has been proved to play a critical role in the progression of various cancers and to influence the immune microenvironment, but its potential role in osteosarcoma remains unclear.

METHODS

We have acquired transcriptomic and clinical data from 84 osteosarcoma samples and 70 normal bone samples from the TARGET and GTEx databases. We identified differentially expressed lactate metabolism-related LncRNAs (LRLs) in osteosarcoma and performed Cox regression and LASSO regression to establish LRLs prognostic signature (LRPS). The reliability of LRPS performance was examined by separate prognostic analysis, viability curves and receiver operating characteristic (ROC) curves. Furthermore, the effects of LRPS on the immune microenvironment of osteosarcoma were investigated, and the functions of the focal genes were experimentally validated.

RESULT

A total of 856 differentially expressed LRLs were identified and 5 of them were selected to construct LRPS, which was a better prognostic predictor for osteosarcoma compared with other published prognostic signatures (AUC up to 0.947 and 0.839 in the training and test groups, respectively, with adj-p<0.05 for KM curves). We found that LRPS significantly affected the immune infiltration of osteosarcoma, while RP11-472M19.2 significantly promoted the metastasis of osteosarcoma, which was well validated experimentally. Encouragingly, a number of sensitive drugs were identified for LRPS and RP11-472M19.2 high-risk groups.

CONCLUSION

Our study shows that lactate metabolism plays a crucial role in the development of osteosarcoma and has been well validated experimentally, providing extremely important insights into the clinical treatment and in-depth research of osteosarcoma.

Impairment of rigidity sensing caused by mutant TP53 gain of function in osteosarcoma

Osteosarcoma (OS) is the most common primary malignant pediatric bone tumor and is characterized by high heterogeneity. Studies have revealed a wide range of phenotypic differences among OS cell lines in terms of their in vivo tumorigenicity and in vitro colony-forming abilities. However, the underlying molecular mechanism of these discrepancies remains unclear. The potential role of mechanotransduction in tumorigenicity is of particular interest. To this end, we tested the tumorigenicity and anoikis resistance of OS cell lines both in vitro and in vivo. We utilized a sphere culture model, a soft agar assay, and soft and rigid hydrogel surface culture models to investigate the function of rigidity sensing in the tumorigenicity of OS cells. Additionally, we quantified the expression of sensor proteins, including four kinases and seven cytoskeletal proteins, in OS cell lines. The upstream core transcription factors of rigidity-sensing proteins were further investigated. We detected anoikis resistance in transformed OS cells. The mechanosensing function of transformed OS cells was also impaired, with general downregulation of rigidity-sensing components. We identified toggling between normal and transformed growth based on the expression pattern of rigidity-sensing proteins in OS cells. We further uncovered a novel TP53 mutation (R156P) in transformed OS cells, which acquired gain of function to inhibit rigidity sensing, thus sustaining transformed growth. Our findings suggest a fundamental role of rigidity-sensing components in OS tumorigenicity as mechanotransduction elements through which cells can sense their physical microenvironment. In addition, the gain of function of mutant TP53 appears to serve as an executor for such malignant programs.

NSUN2 promotes osteosarcoma progression by enhancing the stability of FABP5 mRNA via m5C methylation

5-methylcytosine (m⁵C) modification, which is mainly induced by the RNA methyltransferase NSUN2 (NOP2/Sun domain family, member 2), is an important chemical posttranscriptional modification in mRNA and has been proven to play important roles in the progression of many cancers. However, the functions and underlying molecular mechanisms of NSUN2-mediated m⁵C in osteosarcoma (OS) remain unclear. In this study, we found NSUN2 was highly expressed in OS tissues and cells. We also discovered that higher expression of NSUN2 predicted poorer prognosis of OS patients. Our study showed that NSUN2 could promote the progression of OS cells. Moreover, we employed RNA sequencing, RNA immunoprecipitation (RIP), and methylated RIP to screen and validate the candidate targets of NSUN2 and identified FABP5 as the target. We observed that NSUN2 stabilized FABP5 mRNA by inducing m⁵C modification and further promoted fatty acid metabolism in OS cells. Moreover, both knocking down the expression of FABP5 and adding fatty acid oxidation inhibitor could counterbalance the promoting effect of NSUN2 on the progression of OS. Our study confirms that NSUN2 can up-regulate the expression of FABP5 by improving the stability of FABP5 mRNA via m⁵C, so as to promote fatty acid metabolism in OS cells, and finally plays the role in promoting the progression of OS. Our findings suggest that NSUN2 is a promising prognostic marker for OS patients and may serve as a potential therapeutic target for OS treatment. A schematic illustration was proposed to summarize our findings.

Fatty acid synthase (FASN) inhibits the cervical squamous cell carcinoma (CESC) progression through the Akt/mTOR signaling pathway

BACKGROUND

Cervical cancer is a malignant tumor that affects females and remains the cause of the highest morbidity and mortality among women worldwide. Currently, gene-targeted therapy is a novel treatment option for clinicians. Furthermore, fatty acid synthase (FASN) plays a therapeutic role in various cancers. Nonetheless, the mechanism of action of this enzyme in cervical squamous cell carcinoma and cervical duct adenocarcinoma (CESC) has not yet been reported.

METHODS

RNA (ribonucleic acid) sequencing data and clinical information were obtained from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx). The expression levels of FASN were obtained from Gene Expression Profiling Interactive Analysis 2 (GEPIA2) and Human Protein Atlas (HPA). Univariate and multivariate Cox regression analyses were utilized to assess independent prognostic factors associated with survival. A nomogram and receiver operating characteristic curve (ROC) were employed to evaluate survival and predictive power. In vitro experiments and real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) were conducted to identify cell interference efficiency. MTS, monoclonal formation, and EDU assays were used to determine cell viability. Wound healing and invasion assays (transwell assay) were used to evaluate cell migration and invasion. Finally, Hoechst 33342, propidium iodide (PI) staining and Annexin V-FITC staining were used to assess apoptosis and the cell cycle, while western blotting was utilized to determine the protein expression levels.

RESULTS

FASN was aberrantly expressed in various cancers, including CESC, where it was highly expressed. Kaplan-Meier, univariate, multivariate Cox regression analyses and ROC curve indicated that FASN is a potential key indicator of survival prognosis among CESC patients and demonstrated good predictive ability and efficacy. Complementary in vitro experiments confirmed that FASN is an important target for CESC therapy.

CONCLUSION

The current study validated the biological and clinical significance of FASN in CESC prognosis, suggesting that FASN knockdown may exert antitumor activity against cervical cancer through the Akt/mTOR signaling pathway.

CircREOS suppresses lipid synthesis and osteosarcoma progression through inhibiting HuR-mediated MYC activation

MYC proto-oncogene (MYC) is a transcription factor among the most commonly activated oncoproteins, playing vital roles in lipid metabolism and tumor aggressiveness with broad effects. However, it is still largely unknown about the regulating mechanisms of MYC in osteosarcoma (OS). In this study, we identify a circRNA with Reduced Expression in OS (termed as circREOS) generated from MYC gene, as a novel regulator of MYC and OS progression. CircREOS is down-regulated in OS cells and localized in the nucleus. CircREOS suppresses MYC expression, lipid metabolism and growth, invasion in OS cells. Mechanically, circREOS physically interacts with HuR (human antigen R) protein, and subsequently restrains its binding and activation on the 3'-UTR (untranslated region) of MYC mRNA, resulting in down-regulation of MYC and inhibition of OS. Moreover, circREOS serves as a tumor suppressor via targeting lipid metabolism. CircREOS reduces FASN expression and lipid accumulation through inhibiting MYC-facilitated FASN regulation. Taken together, these results indicate that circREOS suppress lipid synthesis and OS progression through inhibiting HuR-mediated MYC activation, providing a potential therapeutic target for OS.

Comprehensive Analysis of FASN in Tumor Immune Infiltration and Prognostic Value for Immunotherapy and Promoter DNA Methylation

Fatty acid synthase (FASN) promotes tumor progression in multiple cancers. In this study, we comprehensively examined the expression, prognostic significance, and promoter methylation of FASN, and its correlation with immune cell infiltration in pan-cancer. Our results demonstrated that elevated FASN expression was significantly associated with an unfavorable prognosis in many cancer types. Furthermore, FASN promoter DNA methylation can be used as a tumor prognosis marker. Importantly, high levels of FASN were significantly negatively correlated with tumor immune infiltration in 35 different cancers. Additionally, FASN was significantly associated with tumor mutational burden (TMB) and microsatellite instability (MSI) in multiple malignancies, suggesting that it may be essential for tumor immunity. We also investigated the effects of FASN expression on immunotherapy efficacy and prognosis. In up to 15 tumors, it was significantly negatively correlated with immunotherapy-related genes, such as PD-1, PD-L1, and CTLA-4. Moreover, we found that tumors with high FASN expression may be more sensitive to immunotherapy and have a good prognosis with PD-L1 treatment. Finally, we confirmed the tumor-suppressive effect of mir-195-5p through FASN. Altogether, our results suggested that FASN may serve as a novel prognostic indicator and immunotherapeutic target in various malignancies.

HELQ suppresses migration and proliferation of non-small cell lung cancer cells by repairing DNA damage and inducing necrosis

HELQ plays a key role in DNA damage response and cell-cycle checkpoint regulation. It has been implicated in ovarian and pituitary tumors and may play a role in germ cell maintenance. This study investigated the role of HELQ in lung cancer. The expression of HELQ in patients with non-small-cell lung cancer (NSCLC) was downregulated compared with normal human lungs. Clinical prognostic analysis of Kaplan-Meier plots revealed that patients with NSCLC with low HELQ levels had a reduced overall survival. Further, we found that HELQ depletion enhanced lung cancer cell malignancy. Furthermore, overexpression of HELQ in lung cancer cells reduced cell migration in vitro, while DNA damage repair was inhibited. Both in vitro and in vivo studies have shown that HELQ induces cell death. Mechanistically, we found that cells overexpressing HELQ showed a tendency to induce necrosis. After analyzing the database of HELQ interactors. we found that RIPK3 may interact with it and proved this conclusion by immunoprecipitation. Our findings identified the tumor suppressive role of HELQ in malignant human lung cancer and unraveled a potential therapeutic strategy for cancer treatment through HELQ activation. Moreover, HELQ may also be a predictive biomarker for the clinical predisposition, progression, and prognosis of lung cancer.

Extracellular vesicles from bone mesenchymal stem cells transport microRNA-206 into osteosarcoma cells and target NRSN2 to block the ERK1/2-Bcl-xL signaling pathway

Osteosarcoma (OS) is a kind of malignant tumor originating from mesenchymal tissues. Bone mesenchymal stem cells-derived extracellular vesicles (BMSCs-EVs) can play important roles in OS. This study investigated the mechanism of BMSCs-EVs on OS. BMSC surface antigens and adipogenic and osteogenic differentiation were detected by flow cytometry, and oil red O and alizarin red staining. EVs were isolated from BMSCs by differential centrifugation and identified by transmission electron microscopy, nanoparticle tracking analysis, and Western blot (WB). miR-206 and neurensin-2 (NRSN2) levels in human osteoblast hFOB 1.19 or OS cells (143B, MG-63, Saos2, HOS) were detected by RT-qPCR. Human OS cells with lower miR-206 levels were selected and treated with BMSCs-EVs or pSUPER-NRSN2. The uptake of EVs by 143B cells, cell proliferation, apoptosis, invasion, and migration were detected by immunofluorescence, 5-ethynyl-2’-deoxyuridine (EdU) and colony formation assays, flow cytometry, scratch test, and transwell assays. The binding sites between miR-206 and NRSN2 were predicted by Starbase database and verified by dual-luciferase assay. The OS xenograft model was established and treated with BMSCs-EVs. Tumor growth rate and volume, cell proliferation, and p-ERK1/2, ERK1/2, and Bcl-xL levels were detected by vernier caliper, immunohistochemistry, and WB. BMSCs-EVs were successfully extracted. miR-206 was diminished and NRSN2 was promoted in OS cells. BMSCs-EVs inhibited proliferation, migration, and invasion, and promoted apoptosis of OS cells. BMSCs-EVs carried miR-206 into OS cells. Inhibition of miR-206 in EVs partially reversed the inhibitory effect of EVs on malignant behaviors of OS cells. miR-206 targeted NRSN2. Overexpression of NRSN2 reversed the inhibitory effect of EVs on OS cells. NRSN2 activated the ERK1/2-Bcl-xL pathway. BMSC-EVs inhibited OS growth in vivo. In summary, BMSC-EVs targeted NRSN2 and inhibited the ERK1/2-Bcl-xL pathway by carrying miR-206 into OS cells, thus inhibiting OS progression.

α-Linolenic Acid Suppresses Proliferation and Invasion in Osteosarcoma Cells via Inhibiting Fatty Acid Synthase

Fatty acid synthase (FASN) is highly expressed in multiple types of human cancers and is recognized as one of the targets for treating cancer metastasis. α-Linolenic acid is an omega-3 essential fatty acid and it possesses various biological activities. The present study was designed to reveal the effects of α-linolenic acid on osteosarcoma and to reveal whether the mechanism of α-linolenic acid in anticancer activity may be related to FASN inhibition. The cytotoxicity of α-linolenic acid was assessed in osteosarcoma MG63, 143B, and U2OS cells. Cell viability was detected by the MTT assay. The protein expression level was detected by western blotting. Flow cytometry, Annexin V/propidium iodide dual staining, and Hoechst 33258 staining were performed to assess the apoptotic effects. Wound healing assay was applied to detect the inhibitory effect of α-linolenic acid on osteosarcoma cells migration. The results showed that α-linolenic acid downregulated FASN expression. α-Linolenic acid inhibited osteosarcoma cell proliferation and migration in a dose-dependent manner. In addition, α-linolenic acid regulated endoplasmic reticulum transmembrane receptors and signal protein expression in osteosarcoma cells. The findings of the present study suggested that α-linolenic acid suppresses osteosarcoma cell proliferation and metastasis by inhibiting FASN expression, which provides a basis as a potential target for osteosarcoma treatment.

Decreased expression of miR-195 mediated by hypermethylation promotes osteosarcoma

Osteosarcoma (OS) is the most common type of primary malignant bone tumor. The early lung metastasis of osteosarcoma is one of the main factors of poor prognosis. Therefore, searching for new targets and new mechanisms of osteosarcoma metastasis is essential for the prevention and treatment of osteosarcoma. Our previous studies suggested that fatty acid synthase (FASN) was an oncogene and promoted osteosarcoma. In addition, it is reported that the expression of miR-195 was negatively correlated with osteosarcoma. Aberrant DNA methylation can reversely regulate the expression of miRNAs. However, whether miR-195 could target FASN in osteosarcoma and whether ectopic DNA methylation is the upstream regulatory mechanism of miR-195 in metastasis of osteosarcoma are not fully studied. The expressions were detected by qPCR and western blot, and methylation level was determined by methylation-specific PCR. Luciferase reporter assay, MTT, wound healing, and Transwell assay were used. We found that the expression of miR-195 was low in osteosarcoma. The methylation of miR-195 was high. miR-195 targeted and decreased the expression of FASN. In osteosarcoma, miR-195 inhibited cell proliferation, cell migration, and invasion. The methylation of miR-195 was related to decreased miR-195, it might promote osteosarcoma.

CircWHSC1 Promotes Breast Cancer Progression by Regulating the FASN/AMPK/mTOR Axis Through Sponging miR-195-5p

Numerous studies reveal that circular RNAs (circRNAs) affect cancer progression. CircWHSC1 is a novel circRNA that accelerates ovarian cancer progression. Nevertheless, the function of circWHSC1 in regulating breast cancer (BC) is elusive. Here, quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was carried out to detect the profiles of circWHSC1 and miR-195-5p in BC tissues and corresponding non-tumor tissues. Gain- and loss-of-function assays were implemented both in vivo and ex vivo to verify the significance of circWHSC1 in BC development. BC cell proliferation was estimated by the cell counting kit-8 (CCK-8) and BrdU assays. Transwell assay was implemented to test BC cell migration and invasion. The protein levels of FASN, AMPK and mTOR were determined by Western blot. Moreover, immunohistochemistry was performed to examine Ki67 and FASN expression. As shown by the result, circWHSC1 was up-regulated in BC tissues versus adjacent non-tumor tissues. circWHSC1 overexpression was correlated with higher tumor stages, lymphatic metastasis and worse survival of BC patients. Functionally, overexpressing circWHSC1 amplified proliferation, migration and invasion of BC cell lines and boosted xenograft tumor growth in nude mice. Bioinformatics uncovered that circWHSC1 functioned as a competitive endogenous RNA by sponging miR-195-5p, which was further corroborated by the dual-luciferase reporter assay and RNA immunoprecipitation. miR-195-5p delayed BC progression, which was dampened by circWHSC1 up-regulation. Fatty acid synthase (FASN) was affirmed as a direct target of miR-195-5p. miR-195-5p overexpression curbed FASN expression and activated its downstream AMPK pathway. Inhibition of FASN or activation of the AMPK pathway reversed circWHSC1-mediated oncogenic effects. Collectively, CircWHSC1 acted as an oncogene to expedite BC evolvement by modulating the miR-195-5p/FASN/AMPK/mTOR pathway.

Mechanisms, Diagnosis and Treatment of Bone Metastases

Bone and bone marrow are among the most frequent metastatic sites of cancer. The occurrence of bone metastasis is frequently associated with a dismal disease outcome. The prevention and therapy of bone metastases is a priority in the treatment of cancer patients. However, current therapeutic options for patients with bone metastatic disease are limited in efficacy and associated with increased morbidity. Therefore, most current therapies are mainly palliative in nature. A better understanding of the underlying molecular pathways of the bone metastatic process is warranted to develop novel, well-tolerated and more successful treatments for a significant improvement of patients' quality of life and disease outcome. In this review, we provide comparative mechanistic insights into the bone metastatic process of various solid tumors, including pediatric cancers. We also highlight current and innovative approaches to biologically targeted therapy and immunotherapy. In particular, we discuss the role of the bone marrow microenvironment in the attraction, homing, dormancy and outgrowth of metastatic tumor cells and the ensuing therapeutic implications. Multiple signaling pathways have been described to contribute to metastatic spread to the bone of specific cancer entities, with most knowledge derived from the study of breast and prostate cancer. However, it is likely that similar mechanisms are involved in different types of cancer, including multiple myeloma, primary bone sarcomas and neuroblastoma. The metastatic rate-limiting interaction of tumor cells with the various cellular and noncellular components of the bone-marrow niche provides attractive therapeutic targets, which are already partially exploited by novel promising immunotherapies.

Oxygen and metabolic reprogramming in the tumor microenvironment influences metastasis homing

Tumor metastasis is the leading cause of cancer mortality, often characterized by abnormal cell growth and invasion to distant organs. The cancer invasion due to epithelial to mesenchymal transition is affected by metabolic and oxygen availability in the tumor-associated micro-environment. A precise alteration in oxygen and metabolic signaling between healthy and metastatic cells is a substantial probe for understanding tumor progression and metastasis. Molecular heterogeneity in the tumor microenvironment help to sustain the metastatic cell growth during their survival shift from low to high metabolic-oxygen-rich sites and reinforces the metastatic events. This review highlighted the crucial role of oxygen and metabolites in metastatic progression and exemplified the role of metabolic rewiring and oxygen availability in cancer cell adaptation. Furthermore, we have also addressed potential applications of altered oxygen and metabolic networking with tumor type that could be a signature pattern to assess tumor growth and chemotherapeutics efficacy in managing cancer metastasis.

FASN Knockdown Inhibited Anoikis Resistance of Gastric Cancer Cells via P-ERK1/2/Bcl-xL Pathway

Anoikis resistance (AR) is a crucial step in tumor metastasis. The overexpression of fatty acid synthase (FASN) is not only related to the AR of osteosarcoma cells, but also evidenced on gastric cancer (GC). This study investigated the role of FASN in the AR of GC cells. Plates coated with poly-HEMA were used for the culture of cells with AR. Small interfering RNA targeting FASN (siFASN) was transfected into MNK-45 and AGS cells. The number and apoptosis of cells were assessed by a hemacytometer and Annexin-V-FITC/PI assay, respectively. Aggregated cells and colony numbers were manually counted under a microscope. The migration and invasion rates were measured via wound healing and Transwell invasion assays, respectively. The levels of FASN, phosphorylated (p)-ERK1/2, ERK1/2 and Bcl-xL were detected through western blot or quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The results showed that the cell numbers of MNK-45 and AGS were increased while that of GES-1 cell was decreased during the culture in suspension. A higher apoptosis rate and a smaller number of aggregated cells were observed in GES-1 cells in comparison with MNK-45 and AGS cells. A larger colony number, greater migration and invasion rates, and higher mRNA and protein expressions of FASN were presented in the AR group compared with the control group. Cells transfected with siFASN possessed lower migration and invasion rates, reduced expressions of FASN mRNA and protein, p-ERK1/2 and Bcl-xL, and induced a significantly declined ratio of p-ERK1/2 to ERK1/2. These findings suggest that down-regulation of FASN suppresses the AR of GC cells, which may be related to the inhibition of p-ERK1/2/Bcl-xL pathway.

Mechanisms for Modulating Anoikis Resistance in Cancer and the Relevance of Metabolic Reprogramming

The attachment of cells to the extracellular matrix (ECM) is the hallmark of structure–function stability and well-being. ECM detachment in localized tumors precedes abnormal dissemination of tumor cells culminating in metastasis. Programmed cell death (PCD) is activated during tumorigenesis to clear off ECM-detached cells through “anoikis.” However, cancer cells develop several mechanisms for abrogating anoikis, thus promoting their invasiveness and metastasis. Specific factors, such as growth proteins, pH, transcriptional signaling pathways, and oxidative stress, have been reported as drivers of anoikis resistance, thus enhancing cancer proliferation and metastasis. Recent studies highlighted the key contributions of metabolic pathways, enabling the cells to bypass anoikis. Therefore, understanding the mechanisms driving anoikis resistance could help to counteract tumor progression and prevent metastasis. This review elucidates the dynamics employed by cancer cells to impede anoikis, thus promoting proliferation, invasion, and metastasis. In addition, the authors have discussed other metabolic intermediates (especially amino acids and nucleotides) that are less explored, which could be crucial for anoikis resistance and metastasis.

Upregulation of fatty acid synthase in MYC and BCL-2 double-expressor lymphoma

Diffuse large B-cell lymphoma (DLBCL) is the most common and heterogeneous lymphoid malignancy. The subtype with MYC and BCL-2 double-expressor lymphoma (DEL) was defined by its aggressive nature and poor survival outcome. Therefore, the development of effective therapies for the DEL subtype is imperative. Fatty acid synthase (FASN) activity is associated with altered lipid metabolism and aberrant protein translation in DLBCL. However, the inter-regulation of these key processes is not fully determined in DEL. In the present study, the clinical and biological impact of FASN was investigated in the DEL subtype. Initially, FASN expression levels were analyzed from a patient cohort and the data indicated that the highest FASN expression was noted in DEL tissues compared with that noted in the DLBCL and reactive lymphoid hyperplasia tissues. Patients with DEL with combined high-FASN expression indicated poorer EFS outcomes than the rest of the patients. In vitro data indicated that FASN was overexpressed in SU-DHL-2 and U2932 cells. Silencing FASN decreased cell growth and promoted cell apoptosis by modulating the pERK/BCL-2 signaling pathway. In conclusion, the present study indicated that FASN was overexpressed in DEL and that its expression was associated with poor survival outcomes. Furthermore, the data demonstrated that FASN regulated the biological function via the pERK/BCL-2 signaling pathway. FASN serves a critical role in the progression of DEL and its expression may be associated with the development to a more aggressive phenotype of DLBCL. Therefore, it may be considered a potential therapeutic target for DLBCL.

iTRAQ-based proteomic analysis of the molecular mechanisms and downstream effects of fatty acid synthase in osteosarcoma cells

Background

Fatty acid synthase (FASN) is a lipogenic enzyme that participates in tumor progression. We previously showed that FASN is dysregulated in OS malignancy, but the molecular mechanism(s) of these effects remained unclear.

Methods

We examined differentially expressed proteins (DEPs) in FASN‐silenced osteosarcoma 143B cells and their parental cells by isobaric tags for relative and absolute quantitation (iTRAQ). Differentially expressed proteins were classified using GO and KEGG analysis. The association between FASN and heterogeneous nuclear ribonucleoprotein A1 (HNRNPA1) was confirmed using qPCR, Western blot, and immunohistochemistry. The function of HNRNPA1 in osteosarcoma was determined using CCK‐8, colony formation, wound healing, transwell migration, and invasion assays.

Results

Among the 4971 identified proteins, 567 DEPs (325 upregulated and 242 downregulated) were identified. The top 10 upregulated proteins comprised HIST1H2AB, INA, INTS5, MTCH2, EIF1, MAPK1IP1L, PXK, RPS27, PM20D2, and ZNF800, while the top 10 downregulated proteins comprised NDRG1, CNTLN, STON2, GDF7, HECTD3, HBB, TPM1, PPP4R4, PTTG1IP, and PLCB3. Bioinformatic analysis indicated that the DEPs were related to cellular processes, metabolic processes, biological regulation, binding, and catalytic activity. HNRNPA1 was dysregulated in FASN‐silenced 143B and HOS cells. qPCR, Western blot, and immunohistochemistry showed that FASN expression positively correlates with HNRNPA1 expression. Further studies indicated that HNRNPA1 correlates with OS diagnosis and prognosis. And HNRNPA1 silence inhibits the proliferation, migration, and invasion in OS cells.

Conclusion

HNRNPA1 acts as targets downstream of FASN and potential biomarker and oncogene in OS.

Emerging Roles and Potential Biological Value of CircRNA in Osteosarcoma

Circular RNAs (circRNAs) are endogenous noncoding RNAs that are widely found in eukaryotic cells. They have been found to play a vital biological role in the development of human diseases. At present, circRNAs have been involved in the pathogenesis, diagnosis, and targeted treatment of multiple tumors. This article reviews the research progress of circRNAs in osteosarcoma (OSA) in recent years. The potential connection between circRNAs and OSA cell proliferation, apoptosis, metastasis, and chemotherapy sensitivity or resistance, as well as clinical values, is described in this review. Their categories and functions are generally summarized to facilitate a better understanding of OSA pathogenesis, and findings suggest novel circRNA-based methods may be used to investigate OSA and provide an outlook for viable biomarkers and therapeutic targets.

Fatty acid synthase contributes to epithelial-mesenchymal transition and invasion of salivary adenoid cystic carcinoma through PRRX1/Wnt/β-catenin pathway

Fatty acid synthase (FASN) has been shown to be selectively up‐regulated in cancer cells to drive the development of cancer. However, the role and associated mechanism of FASN in regulating the malignant progression of salivary adenoid cystic carcinoma (SACC) still remains unclear. In this study, we demonstrated that FASN inhibition attenuated invasion, metastasis and EMT of SACC cells as well as the expression ofPRRX1, ZEB1, Twist, Slug and Snail, among which the level of PRRX1 changed the most obviously. Overexpression of PRRX1 restored migration and invasion in FASN knockdown cells, indicating that PRRX1 is an important downstream target of FASN signalling. Levels of cyclin D1 and c‐Myc, targets of Wnt/β‐catenin pathway, were significantly decreased by FASN silencing and restored by PRRX1 overexpression. In addition, FASN expression was positively associated with metastasis and poor prognosis of SACC patients as well as with the expression of PRRX1, cyclin D1 and c‐Myc in SACC tissues. Our findings revealed that FASN in SACC progression may induce EMT in a PRRX1/Wnt/β‐catenin dependent manner.

Lipids in the tumor microenvironment: From cancer progression to treatment

Over the past decade, the study of metabolic abnormalities in cancer cells has risen dramatically. Cancer cells can thrive in challenging environments, be it the hypoxic and nutrient-deplete tumor microenvironment or a distant tissue following metastasis. The ways in which cancer cells utilize lipids are often influenced by the complex interactions within the tumor microenvironment and adjacent stroma. Adipocytes can be activated by cancer cells to lipolyze their triglyceride stores, delivering secreted fatty acids to cancer cells for uptake through numerous fatty acid transporters. Cancer-associated fibroblasts are also implicated in lipid secretion for cancer cell catabolism and lipid signaling leading to activation of mitogenic and migratory pathways. As these cancer-stromal interactions are exacerbated during tumor progression, fatty acids secreted into the microenvironment can impact infiltrating immune cell function and phenotype. Lipid metabolic abnormalities such as increased fatty acid oxidation and de novo lipid synthesis can provide survival advantages for the tumor to resist chemotherapeutic and radiation treatments and alleviate cellular stresses involved in the metastatic cascade. In this review, we highlight recent literature that demonstrates how lipids can shape each part of the cancer lifecycle and show that there is significant potential for therapeutic intervention surrounding lipid metabolic and signaling pathways.

LMP1 promotes nasopharyngeal carcinoma metastasis through NTRK2-mediated anoikis resistance

Anoikis resistance is an important mechanism that mediates tumor metastasis. Studies have found that Epstein-Barr virus (EBV)-encoded latent membrane protein 1 (LMP1) promotes the occurrence, development, and metastasis of nasopharyngeal carcinoma (NPC). However, the related mechanism, especially whether LMP1 is involved in NPC metastasis through anoikis resistance, has not yet been elucidated. In present study, we showed that LMP1 enhanced the ability of NPC cells to resist anoikis by upregulating neurotrophic tyrosine kinase receptor type 2 (NTRK2 or TrkB) expression through NF-κB signaling and promoted the migration and invasion of NPC cells. After knockdown of NTRK2, the p-ERK and p-AKT in NPC cells were inhibited, and twist expression was further reduced, resulting in upregulation of E-cadherin expression and downregulation of vimentin expression. Subsequently, the results of a xenograft experiment showed that inhibiting NTRK2 could reduce LMP1-mediated NPC metastasis in vivo. In summary, these findings demonstrated that EBV-LMP1 upregulates twist expression to promote epithelial-mesenchymal transition (EMT) through the NTRK2-mediated AKT/ERK signaling pathway, thus mediating anoikis resistance and promoting NPC metastasis. These data will provide new molecular markers and potential targets for NPC metastasis.

Understanding and Modeling Metastasis Biology to Improve Therapeutic Strategies for Combating Osteosarcoma Progression

Osteosarcoma is a malignant primary tumor of bone, arising from transformed progenitor cells with osteoblastic differentiation and osteoid production. While categorized as a rare tumor, most patients diagnosed with osteosarcoma are adolescents in their second decade of life and underscores the potential for life changing consequences in this vulnerable population. In the setting of localized disease, conventional treatment for osteosarcoma affords a cure rate approaching 70%; however, survival for patients suffering from metastatic disease remain disappointing with only 20% of individuals being alive past 5 years post-diagnosis. In patients with incurable disease, pulmonary metastases remain the leading cause for osteosarcoma-associated mortality; yet identifying new strategies for combating metastatic progression remains at a scientific and clinical impasse, with no significant advancements for the past four decades. While there is resonating clinical urgency for newer and more effective treatment options for managing osteosarcoma metastases, the discovery of druggable targets and development of innovative therapies for inhibiting metastatic progression will require a deeper and more detailed understanding of osteosarcoma metastasis biology. Toward the goal of illuminating the processes involved in cancer metastasis, a convergent science approach inclusive of diverse disciplines spanning the biology and physical science domains can offer novel and synergistic perspectives, inventive, and sophisticated model systems, and disruptive experimental approaches that can accelerate the discovery and characterization of key processes operative during metastatic progression. Through the lens of trans-disciplinary research, the field of comparative oncology is uniquely positioned to advance new discoveries in metastasis biology toward impactful clinical translation through the inclusion of pet dogs diagnosed with metastatic osteosarcoma. Given the spontaneous course of osteosarcoma development in the context of real-time tumor microenvironmental cues and immune mechanisms, pet dogs are distinctively valuable in translational modeling given their faithful recapitulation of metastatic disease progression as occurs in humans. Pet dogs can be leveraged for the exploration of novel therapies that exploit tumor cell vulnerabilities, perturb local microenvironmental cues, and amplify immunologic recognition. In this capacity, pet dogs can serve as valuable corroborative models for realizing the science and best clinical practices necessary for understanding and combating osteosarcoma metastases.

Metabolic Remodeling as a Way of Adapting to Tumor Microenvironment (TME), a Job of Several Holders

The microenvironment depends and generates dependence on all the cells and structures that share the same niche, the biotope. The contemporaneous view of the tumor microenvironment (TME) agrees with this idea. The cells that make up the tumor, whether malignant or not, behave similarly to classes of elements within a living community. These elements inhabit, modify and benefit from all the facilities the microenvironment has to offer and that will contribute to the survival and growth of the tumor and the progression of the disease.The metabolic adaptation to microenvironment is a crucial process conducting to an established tumor able to grow locally, invade and metastasized. The metastatic cancer cells are reasonable more plastic than non-metastatic cancer cells, because the previous ones must survive in the microenvironment where the primary tumor develops and in addition, they must prosper in the microenvironment in the metastasized organ.The metabolic remodeling requires not only the adjustment of metabolic pathways per se but also the readjustment of signaling pathways that will receive and obey to the extracellular instructions, commanding the metabolic adaptation. Many diverse players are pivotal in cancer metabolic fitness from the initial signaling stimuli, going through the activation or repression of genes, until the phenotype display. The new phenotype will permit the import and consumption of organic compounds, useful for energy and biomass production, and the export of metabolic products that are useless or must be secreted for a further recycling or controlled uptake. In the metabolic network, three subsets of players are pivotal: (1) the organic compounds; (2) the transmembrane transporters, and (3) the enzymes.This chapter will present the "Pharaonic" intent of diagraming the interplay between these three elements in an attempt of simplifying and, at the same time, of showing the complex sight of cancer metabolism, addressing the orchestrating role of microenvironment and highlighting the influence of non-cancerous cells.