Overexpression of fatty acid synthase in human urinary bladder cancer and combined expression of the synthase and Ki-67 as a predictor of prognosis of cancer patients

Integrative multi-omics analysis depicts the methylome and hydroxymethylome in recurrent bladder cancers and identifies biomarkers for predicting PD-L1 expression

BACKGROUND

Urinary bladder cancer (UBC) is a common malignancy of the urinary tract; however, the mechanism underlying its high recurrence and responses to immunotherapy remains unclear, making clinical outcome predictions difficult. Epigenetic alterations, especially DNA methylation, play important roles in bladder cancer development and are increasingly being investigated as biomarkers for diagnostic or prognostic predictions. However, little is known about hydroxymethylation since previous studies based on bisulfite-sequencing approaches could not differentiate between 5mC and 5hmC signals, resulting in entangled methylation results.

METHODS

Tissue samples of bladder cancer patients who underwent laparoscopic radical cystectomy (LRC), partial cystectomy (PC), or transurethral resection of bladder tumor (TURBT) were collected. We utilized a multi-omics approach to analyze both primary and recurrent bladder cancer samples. By integrating various techniques including RNA sequencing, oxidative reduced-representation bisulfite sequencing (oxRRBS), reduced-representation bisulfite sequencing (RRBS), and whole exome sequencing, a comprehensive analysis of the genome, transcriptome, methylome, and hydroxymethylome landscape of these cancers was possible.

RESULTS

By whole exome sequencing, we identified driver mutations involved in the development of UBC, including those in FGFR3, KDMTA, and KDMT2C. However, few of these driver mutations were associated with the down-regulation of programmed death-ligand 1 (PD-L1) or recurrence in UBC. By integrating RRBS and oxRRBS data, we identified fatty acid oxidation-related genes significantly enriched in 5hmC-associated transcription alterations in recurrent bladder cancers. We also observed a series of 5mC hypo differentially methylated regions (DMRs) in the gene body of NFATC1, which is highly involved in T-cell immune responses in bladder cancer samples with high expression of PD-L1. Since 5mC and 5hmC alternations are globally anti-correlated, RRBS-seq-based markers that combine the 5mC and 5hmC signals, attenuate cancer-related signals, and therefore, are not optimal as clinical biomarkers.

CONCLUSIONS

By multi-omics profiling of UBC samples, we showed that epigenetic alternations are more involved compared to genetic mutations in the PD-L1 regulation and recurrence of UBC. As proof of principle, we demonstrated that the combined measurement of 5mC and 5hmC levels by the bisulfite-based method compromises the prediction accuracy of epigenetic biomarkers.

Metabolomic credentialing of murine carcinogen-induced urothelial cancer

Bladder cancer (BCa) is the most common malignancy of the urinary system with increasing incidence, mortality, and limited treatment options. Therefore, it is imperative to validate preclinical models that faithfully represent BCa cellular, molecular, and metabolic heterogeneity to develop new therapeutics. We performed metabolomic profiling of premalignant and non-muscle invasive bladder cancer (NMIBC) that ensued in the chemical carcinogenesis N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN) mouse model. We identified the enriched metabolic signatures that associate with premalignant and NMIBC. We found that enrichment of lipid metabolism is the forerunner of carcinogen-induced premalignant and NMIBC lesions. Cross-species analysis revealed the prognostic value of the enzymes associated with carcinogen-induced enriched metabolic in human disease. To date, this is the first study describing the global metabolomic profiles associated with early premalignant and NMIBC and provide evidence that these metabolomic signatures can be used for prognostication of human disease.

Upregulation of Fatty Acid Transporters is Associated With Tumor Progression in Non-Muscle-Invasive Bladder Cancer

As patients with non-muscle-invasive bladder cancer (NMIBC) show a high degree of heterogeneity in tumor recurrence or progression, many clinicians demand a detailed risk stratification. Although modified fatty acid metabolism in cancer cells is reported to reflect malignant phenotypes such as metastasis, the impact of fatty acid transporters on NMIBC has never been investigated. This study examined the clinicopathologic implications of fatty acid transporters such as fatty acid transport protein 4 (FATP4), cluster of differentiation 36/fatty acid translocase (CD36/FAT), and long chain acyl CoA synthetase 1 (ACSL1) in 286 NMIBC cases. This study revealed that FATP4, CD36, and ACSL1 were overexpressed in 123 (43.0%), 43 (15.0%), and 35 (12.2%) NMIBC cases, respectively. High FATP4 in tumor cells was associated with high grade (p = 0.004) and high stage (p = 0.039). High CD36 was related to high grade (p < 0.001), high stage (p = 0.002), and non-papillary growth type (p = 0.004). High ACSL1 showed an association with high grade (p < 0.001), high stage (p = 0.01), non-papillary growth type (p = 0.002), and metastasis (p = 0.033). High FATP4 was an independent factor predicting short overall survival (OS) (hazard ratio = 3.32; 95% confidence interval, 1.07-10.31; p = 0.038). In conclusion, upregulation of FATP4, CD36, and ACSL1 might promote the NMIBC progression and could be exploited in clinical risk stratification and targeted therapy.

S-Palmitoylation as a Functional Regulator of Proteins Associated with Cisplatin Resistance in Bladder Cancer

Protein S-palmitoylation is a powerful post-translational modification that regulates protein trafficking, localization, turnover, and signal transduction. Palmitoylation controls several important cellular processes, and, if dysregulated, can lead to cancer, cardiovascular disease, and neurological disorders. The role of protein palmitoylation in mediating resistance to systemic cisplatin-based chemotherapies in cancer is currently unknown. This is of particular interest because cisplatin is currently the gold standard of treatment for bladder cancer (BC), and there are no feasible options after resistance is acquired. Using unbiased global proteomic profiling of purified S-palmitoylated peptides combined with intensive bioinformatics analyses, we identified 506 candidate palmitoylated proteins significantly enriched in cisplatin-resistant BC cells. One of these proteins included PD-L1, which is highly palmitoylated in resistant cells. Pharmacological inhibition of fatty acid synthase (FASN) suppressed PD-L1 palmitoylation and expression, which suggests the potential use of FASN-PD-L1-targeted therapeutic strategies in BC patients. Taken together, these results highlight the role of protein palmitoylation in mediating BC chemoresistance.

NMR-derived targeted serum metabolic biomarkers appraisal of bladder cancer: A pre- and post-operative evaluation

With high morbidity and mortality, urinary bladder cancer (BC) ranks fifth among common cancers globally. The inherent limitations of urine cytology and cystoscopy, and marginal enhancements in the rate of survival promt us to develop surrogate serum based metabolic biomarkers of screening, identification, and follow-up protocols of management for BC patients. Earlier, we exhibited that abnormal expression levels of dimethylamine (DMA), malonate, lactate, glutamine, histidine, and valine in serum may be used as signature metabolites to differentiate BC from healthy controls (HC) (J. Proteome Res. 2013; 12(12):5839-50). Here we further gauge and validate these observations by comparing pre-operative to post-operative follow-up BC patients. This study was conducted on 160 sera samples involving HC (n = 52), pre-operative (n = 55) and post-operative (n = 53) BC cases. ¹H nuclear magnetic resonance (NMR) spectroscopy was used to generate serum metabolic profiles and to gauge aberrantly expressed metabolites. The targeted metabolomic approach revealed that the expression levels of these signature metabolites were progressively and significantly decreased in post-operative follow-up at the interval of 30, 60, and 90 days compared to pre-operative BC sera samples and were maintained at HC levels. Serum metabolic biomarkers appear to be an inspiring and least-invasive tactic for detection and prognosticating BC patient follow-up.

Multi-omics Integration Analysis Robustly Predicts High-Grade Patient Survival and Identifies CPT1B Effect on Fatty Acid Metabolism in Bladder Cancer

PURPOSE

The perturbation of metabolic pathways in high-grade bladder cancer has not been investigated. We aimed to identify a metabolic signature in high-grade bladder cancer by integrating unbiased metabolomics, lipidomics, and transcriptomics to predict patient survival and to discover novel therapeutic targets.

EXPERIMENTAL DESIGN

We performed high-resolution liquid chromatography mass spectrometry (LC-MS) and bioinformatic analysis to determine the global metabolome and lipidome in high-grade bladder cancer. We further investigated the effects of impaired metabolic pathways using in vitro and in vivo models.

RESULTS

We identified 519 differential metabolites and 19 lipids that were differentially expressed between low-grade and high-grade bladder cancer using the NIST MS metabolomics compendium and lipidblast MS/MS libraries, respectively. Pathway analysis revealed a unique set of biochemical pathways that are highly deregulated in high-grade bladder cancer. Integromics analysis identified a molecular gene signature associated with poor patient survival in bladder cancer. Low expression of CPT1B in high-grade tumors was associated with low FAO and low acyl carnitine levels in high-grade bladder cancer, which were confirmed using tissue microarrays. Ectopic expression of the CPT1B in high-grade bladder cancer cells led to reduced EMT in in vitro, and reduced cell proliferation, EMT, and metastasis in vivo.

CONCLUSIONS

Our study demonstrates a novel approach for the integration of metabolomics, lipidomics, and transcriptomics data, and identifies a common gene signature associated with poor survival in patients with bladder cancer. Our data also suggest that impairment of FAO due to downregulation of CPT1B plays an important role in the progression toward high-grade bladder cancer and provide potential targets for therapeutic intervention.

Fatty acid synthase, Her2/neu, and E2F1 as prognostic markers of progression in non-muscle invasive bladder cancer

Non-muscle-invasive bladder cancer (NMIBC) is a heterogeneous disease which has an unpredictable risk of progression to muscle-invasive bladder cancer (MIBC). The selection of patients who may benefit from early radical intervention is a challenge. To define the useful prognostic markers for progression, we analyzed the immunohistochemical expression of fatty acid synthase (FASN), Her2/neu, and E2F1 in 60 cases of NMIBC who underwent TURBT and adjuvant intravesical bacillus-Calmette-Guérin (BCG). Their predicting role for tumor recurrence, progression, recurrence-free survival (RFS) and progression-free survival (PFS) was analyzed. High FASN expression was observed in 56.7% (34/60) of NMIBC cases, and FASN expression was significantly associated with the tumor size, grade, and tumor stage (p = 0.003, p < 0.001, p < 0.0001 respectively). Positive Her2/neu was noted in 18.3% (11/60) of the cases, and its expression was significantly associated with the tumor size, histologic grade, and tumor stage (p = 0.001, p = 0.002, p = 0.011 respectively). High E2F1 expression was detected in 40% of the cases, and it was associated with tumor size, histologic grade, and tumor stage (p < 0.001 for each). Analysis of follow-up period revealed that NMIBC with high FASN, positive Her2/neu, and high E2F1 expression exhibited a potent relation with tumor progression, shorter RFS, and poor PFS. Conclusions: High FASN, Her2/neu, and E2F1 are considered as adverse prognostic factors of tumor recurrence and progression in NMIBC and these patients should be followed carefully. Therefore, we suggest that FASN, Her2/neu, and E2F1 should be considered and evaluated during the selection of the appropriate management strategy for NMIBC patients.

Decreased Oleic Acid and Marine n - 3 Polyunsaturated Fatty Acids in Tunisian Patients with Urothelial Bladder Cancer

Fatty acids (FAs) are thought to impact carcinogenesis by affecting cell signaling. A case-control study including 250 patients with urothelial bladder cancer (UBC) and 250 controls was conducted. Plasma FAs composition was assessed using capillary gas chromatography. Associations of individual and classes of FAs with UBC were controlled for the main risk factors for UBC. Plasma FAs profile was different in patients compared to controls. Higher levels (third tertile vs. first tertile) in palmitic acid (PA) [multi-adjusted OR (95% CI), 1.83 (1.14-2.92)], and n - 6:n - 3 FA ratio [4.13 (2.38-7.16)] were associated with increased risk for UBC [multi-adjusted OR (95% CI), 1.83 (1.14-2.92)]. In contrast, higher levels (third tertile vs. first tertile) in oleic [0.54 (0.34-0.86)], dihomo-γ-linolenic (DGLA) [0.47 (0.29-0.74)], eicosapentaenoic (EPA) [0.32 (0.19-0.52)], and docosahexaenoic (DHA) acids [0.33 (0.20-0.53)] were associated with lower risk for UBC. Although the study design does not allow proving causality, the findings suggest a possible protective role of oleic acid and marine n - 3 polyunsaturated FAs (PUFAs) against bladder carcinogenesis.

Increased expression of the gene encoding stearoyl-CoA desaturase 1 in human bladder cancer

Bladder cancer is a common disease and a significant cause of death worldwide. There is thus great interest in identifying a diagnostic and prognostic biomarker, as well as gaining an understanding of the molecular basis of bladder cancer. Stearoyl-CoA desaturase 1 gene (SCD1) is highly overexpressed in many human cancers. However, the expression of SCD1 has not yet been investigated in patients with bladder cancer. Here, we document that (a) the SCD1 is highly overexpressed in human bladder cancer; (b) high expression of SCD1 is more frequently observed in the late stage of disease and patients with lymph node metastasis; (c) bladder cancer patients with a higher SCD1 mRNA level have a poorer survival rate than those with normal SCD1 expression. Overall, this is the first report to indicate an association between SCD1 mRNA level and clinical indicators of human bladder cancer. Our study has provided evidence supporting the potential role of SCD1 as a biomarker for human bladder cancer prognosis.

Quantitative proteomic analysis reveals that proteins required for fatty acid metabolism may serve as diagnostic markers for gastric cancer

BACKGROUND

Gastric cancer is one of the leading causes of cancer-related deaths worldwide. The sensitivities and specificities of current biomarkers for gastric cancer are insufficient for clinical detection, and new diagnostic tests are therefore urgently required.

METHODS

A discovery set of gastric cancer and adjacent normal tissues were analyzed for differentially expressed proteins by labeling of peptide digests with isobaric tag for relative and absolute quantitation (iTRAQ) reagents followed by liquid chromatography-electrospray ionization-tandem mass spectrometry. A validation set of 70 pairs of gastric cancer and adjacent normal tissues were examined to confirm the expression levels of the potential biomarkers identified by iTRAQ labeling.

RESULTS

We detected 431 proteins associated with 16 KEGG pathways that were differentially expressed in gastric cancer tissues, of which 224 were upregulated and 207 were downregulated in gastric cancer tissues. Coexpression of fatty acid binding protein (FABP1) and fatty acid synthase (FASN) in gastric cancer tissues (61.4% sensitivity and 77.1% specificity) was strongly associated with lymph node metastasis and Tumor, Node, Metastasis stage I/II.

CONCLUSION

Quantitative proteomic analysis of gastric cancer tissues revealed that coexpression of FABP1 and FASN may serve as a biomarker for detection of early gastric cancer.

The development of plasma pseudotargeted GC-MS metabolic profiling and its application in bladder cancer

Bladder cancer (BC) is a fatal malignancy with considerable mortality. BC urinary metabolomics has been extensively investigated for biomarker discovery, but few BC blood metabolomic studies have been performed. Hence, a plasma pseudotargeted metabolomic method based on gas chromatography-mass spectrometry with selected ion monitoring (GC-MS-SIM) was developed to study metabolic alterations in BC. The analytical performance of the developed method was compared with that of a nontargeted method. The relative standard deviation (RSD) values of 89 and 70.7 % of the peaks obtained using the pseudotargeted and nontargeted methods, respectively, were less than 20 %. The Pearson correlations of 90.7 and 78.3 % of the peaks obtained using the pseudotargeted and nontargeted methods, respectively, exceeded 0.90 in the linearity evaluation. Compared with the nontargeted method, the signal-to-noise ratios (S/N) of 97.9 and 69.3 % of the peaks increased two- and fivefold, respectively. The developed method was fully validated, with good precision, recovery, and stability of the trimethylsilyl (TMS) derivatives. The method was applied to investigate BC. Significant increases in the contents of metabolites involved in, for example, the pentose phosphate pathway (PPP) and nucleotide and fatty acid synthesis were found in the high-grade (HG) BC group compared to the healthy control (HC) group. These differences imply that the activated PPP may regulate BC cell proliferation by promoting lipid and nucleotide biosynthesis and the detoxification of reactive oxygen species (ROS). These results illustrate that the plasma pseudotargeted method is a powerful tool for metabolic profiling. Graphical abstract The plasma pseudotargeted metabolic profiling suggested the metabolic alterations in bladder cancer (BC) and the significantly differential metabolites for BC discrimination.

High Ki-67 Immunohistochemical Reactivity Correlates With Poor Prognosis in Bladder Carcinoma: A Comprehensive Meta-Analysis with 13,053 Patients Involved

Ki-67 is considered as one of prime biomarkers to reflect cell proliferation and immunohistochemical Ki-67 staining has been widely applied in clinical pathology. To solve the widespread controversy whether Ki-67 reactivity significantly predicts clinical prognosis of bladder carcinoma (BC), we performed a comprehensive meta-analysis by combining results from different literature. A comprehensive search was conducted in the Chinese databases of WanFang, China National Knowledge Infrastructure and Chinese VIP as well as English databases of PubMed, ISI web of science, EMBASE, Science Direct, and Wiley online library. Independent studies linking Ki-67 to cancer-specific survival (CSS), disease-free survival (DFS), overall survival (OS), progression-free survival (PFS), and recurrence-free survival (RFS) were included in our meta-analysis. With the cut-off values literature provided, hazard ratio (HR) values between the survival distributions were extracted and later combined with STATA 12.0. In total, 76 studies (n = 13,053 patients) were eligible for the meta-analysis. It was indicated in either univariate or multivariate analysis for survival that high Ki-67 reactivity significantly predicted poor prognosis. In the univariate analysis, the combined HR for CSS, DFS, OS, PFS, and RFS were 2.588 (95% confidence interval [CI]: 1.623-4.127, P < 0.001), 2.697 (95%CI: 1.874-3.883, P < 0.001), 2.649 (95%CI: 1.632-4.300, P < 0.001), 3.506 (95%CI: 2.231-5.508, P < 0.001), and 1.792 (95%CI: 1.409-2.279, P < 0.001), respectively. The pooled HR of multivariate analysis for CSS, DFS, OS, PFS, and RFS were 1.868 (95%CI: 1.343-2.597, P < 0.001), 2.626 (95%CI: 2.089-3.301, P < 0.001), 1.104 (95%CI: 1.008-1.209, P = 0.032), 1.518 (95%CI: 1.299-1.773, P < 0.001), and 1.294 (95%CI: 1.203-1.392, P < 0.001), respectively. Subgroup analysis of univariate analysis by origin showed that Ki-67 reactivity significantly correlated with all 5 clinical outcome in Asian and European-American patients (P < 0.05). For multivariate analysis, however, the pooled results were only significant for DFS, OS, and RFS in Asian patients, for CSS, DFS, PFS, and RFS in European-American patients (P < 0.05). In the subgroup with low cut-off value (<20%), our meta-analysis indicated that high Ki-67 reactivity was significantly correlated with worsened CSS, DFS, OS, PFS, and RFS on univariate analysis (P < 0.05). For multivariate analysis, the meta-analysis of literature with low cut-off value (<20%) demonstrated that high Ki-67 reactivity predicted shorter DFS, PFS, and RFS in BC patients (P < 0.05). In the subgroup analysis of high cut-off value (≥20%), our meta-analysis indicated that high Ki-67 reactivity, in either univariate or multivariate analysis, significantly correlated with all five clinical outcomes in BC patients (P < 0.05). The meta-analysis indicates that high Ki-67 reactivity significantly correlates with deteriorated clinical outcomes in BC patients and that Ki-67 can be considered as an independent indicator for the prognosis by the meta-analyses of multivariate analysis.

Immunoprofile-based subgrouping of urothelial bladder carcinomas for survival prediction

One of the major challenges in bladder cancer management is in distinguishing aggressive from indolent tumors with similar clinicopathological factors, especially in cases of high-grade T1 stage tumors. To define a set of prognostic factors that can be easily assessed in clinical practice with a high cost-effectiveness, the expressions of 11 proteins were examined immunohistochemically in 403 cases of transurethral resection of bladder tumors, then correlated to clinical outcomes. Based on the protein immunoprofiles, urothelial carcinomas were divided into 4 intrinsic molecular subgroups with different clinical outcomes: subgroups 1 and 4 with the poorest survival, subgroup 2 with the best survival, and subgroup 3 with the intermediate survival outcome. The protein expression patterns of the 4 subgroups were mutually exclusive: overexpression of p53, EZH2, E2F1, and IMP3 and high Ki-67 proliferation index in subgroup 1; overexpression of cytoplasmic survivin in subgroup 4; overexpression of membranous TSP1 and cytoplasmic p27 in subgroup 2; and no representative protein overexpression in subgroup 3. Using these protein immunoprofiles, 3 risk groups were generated, which predicted disease-specific survival not only in total bladder carcinoma cases with 0.737 of predictive accuracy but also in high-grade stage T1 tumors with 0.658 of predictive accuracy. These results showed that urothelial carcinomas were composed of 4 clinically relevant molecular subgroups based on protein expression and that overall survival of those patients could be predicted using a set of a small number of protein expressions not only in total cases but also in high-grade stage T1 tumors.

Up-regulation of fatty acid synthase induced by EGFR/ERK activation promotes tumor growth in pancreatic cancer

Lipid metabolism is dysregulated in many human diseases including atherosclerosis, type 2 diabetes and cancers. Fatty acid synthase (FASN), a key lipogenic enzyme involved in de novo lipid biosynthesis, is significantly upregulated in multiple types of human cancers and associates with tumor progression. However, limited data is available to understand underlying biological functions and clinical significance of overexpressed FASN in pancreatic ductal adenocarcinoma (PDAC). Here, upregulated FASN was more frequently observed in PDAC tissues compared with normal pancreas in a tissue microarray. Kaplan-Meier survival analysis revealed that high expression level of FASN resulted in a significantly poor prognosis of PDAC patients. Knockdown or inhibition of endogenous FASN decreased cell proliferation and increased cell apoptosis in HPAC and AsPC-1 cells. Furthermore, we demonstrated that EGFR/ERK signaling accounts for elevated FASN expression in PDAC as ascertained by performing siRNA assays and using specific pharmacological inhibitors. Collectively, our results indicate that FASN exhibits important roles in tumor growth and EGFR/ERK pathway is responsible for upregulated expression of FASN in PDAC.

Dietary lipids and adipocytes: potential therapeutic targets in cancers

Lipids play an important role to support the rapid growth of cancer cells, which can be derived from both the endogenous synthesis and exogenous supplies. Enhanced de novo fatty acid synthesis and mobilization of stored lipids in cancer cells promote tumorigenesis. Besides, lipids and fatty acids derived from diet or transferred from neighboring adipocytes also influence the proliferation and metastasis of cancer cells. Indeed, the pathogenic roles of adipocytes in the tumor microenvironment have been recognized recently. The adipocyte-derived mediators or the cross talk between adipocytes and cancer cells in the microenvironment is gaining attention. This review will focus on the impacts of lipids on cancers and the pathogenic roles of adipocytes in tumorigenesis and discuss the possible anticancer therapeutic strategies targeting lipids in the cancer cells.

Expression and roles of fatty acid synthase in hepatocellular carcinoma

Cell metabolism abnormalities are closely related to tumor occurrence and development. Fatty acid synthase (FASN) is the key molecule for catalyzing fatty acid synthesis. Increasing evidence indicates that FASN is highly expressed in a number of malignant tumors; it can promote the synthesis of endogenous fatty acids in tumor cells and then the synthesized fatty acids provide energy for the proliferation of tumor cells. However, there has been no systematic study focusing on FASN expression and function in hepatocellular carcinoma (HCC). The aim of the present study was to verify the high expression of FASN in HCC cells at the histological and cellular levels, and to construct FASN shRNA eukaryotic expression vector for interfering FASN expression in HCC cell line SK-Hep-1, in an effort to explore the role of FASN in the proliferation, apoptosis, invasion and migration of HCC cells. In the present study, we demonstrated that FASN was highly expressed in HCC tissues compared with tumor-adjacent tissue and normal liver cell line 7702 (P<0.05). FASN expression in the high metastatic MHCC97H and SK-Hep-1 cell lines was increased compared with low metastatic HCC cell lines (P<0.05). Then, we constructed a FASN shRNA eukaryotic expression vector; after HCC SK-Hep-1 cells were transfected, the cell proliferation, migration and invasion were inhibited, but FASN had no impact on the apoptosis of HCC cells. Collectively, these data indicate that FASN is possibly involved in the occurrence and metastasis of HCC. Thus, inhibition of FASN may be a promising approach for the treatment of HCC.

Prognostic impact of fatty acid synthase expression in upper urinary tract urothelial carcinoma

OBJECTIVE

Fatty acid synthase has been shown to be highly expressed in various types of cancers with increased tumour aggressiveness. In this study we examined the level of fatty acid synthase expression in surgically resected upper urinary tract urothelial carcinoma specimens and evaluated the relations between fatty acid synthase expression and the patients' pathological features and clinical outcomes.

METHODS

Sections of paraffin-embedded tumour specimens from 113 patients who underwent surgical treatment for upper urinary tract urothelial carcinoma were immunostained with a polyclonal fatty acid synthase antibody, and a tumour was considered to have high fatty acid synthase expression if >50% of the cancer cells stained with moderate-to-strong intensity. Associations between fatty acid synthase expression and the patients' pathological parameters and survival were analyzed statistically.

RESULTS

During the follow-up time (median: 46.8 months), 61 patients (54.0%) had recurrence and 17 (15.0%) died of upper urinary tract urothelial carcinoma. High fatty acid synthase expression was significantly associated with high tumour grade (P = 0.0273). Patients with high fatty acid synthase expression had significantly worse recurrence-free survival and extravesical-recurrence-free survival than those with low fatty acid synthase expression (P = 0.0171, P = 0.0228, respectively). In multivariate analysis, high fatty acid synthase expression was an independent predictor of shortened recurrence-free survival (P = 0.0220, hazard ratio (HR) = 1.970).

CONCLUSIONS

Fatty acid synthase expression in upper urinary tract urothelial carcinoma is an independent predictor for tumour recurrence. Patients with high fatty acid synthase expression in upper urinary tract urothelial carcinoma should be followed carefully and adjuvant therapy for them should be considered.

Elevated levels of serum fatty acid synthase in patients with gastric carcinoma

Gastric cancer is the second leading cause of cancer mortality in the world. It is important to develop biomarkers for detecting new cancers at an early stage and for treating them early during recurrence in order to guide optimal treatment. Fatty acid synthase (FAS) is highly expressed in numerous human cancers and thus could potentially serve as such a biomarker, but the potential utility of measuring FAS for detecting gastric cancer has not been previously investigated. The aim of the present study was to provide a preliminary assessment of serum FAS as a marker of gastric carcinoma. The study included 47 patients with gastric cancer and 150 healthy subjects. Blood samples were collected from each cancer patient prior to treatment. Serum FAS levels were measured by ELISA and compared across the two groups of patients. Significantly higher levels of serum FAS were found in the gastric cancer patients [95% confidence interval (CI), 30.37–52.46] compared with the healthy controls (95% CI, 1.331–2.131), with elevated levels even in patients with early-stage tumors. These results indicate that measuring serum FAS levels has strong potential to provide a biomarker for the detection of gastric cancer, with high sensitivity and specificity.

Fatty acid synthase overexpression in adult testicular germ cell tumors: potential role in the progression of non-seminomatous germ cell tumors

Overexpression of fatty acid synthase (FASN), which is a key enzyme responsible for the endogenous synthesis of fatty acids, and its association with multistep progression have been demonstrated in various human malignant tumors. We aimed to clarify the potential role of FASN overexpression in the development and progression of adult testicular germ cell tumors (TGCTs). From the primary sites of a cohort of 113 TGCT cases, we obtained 221 histological components: 53 intratubular germ cell neoplasias, unclassified (IGCNUs), 84 seminomas, 32 embryonal carcinomas, seven choriocarcinomas, 21 yolk sac tumors, and 24 teratomas. Samples were analyzed for overexpression of FASN by immunohistochemistry. Intensities of immunoreactivity and the fraction of positive cells were classified into each four categories (intensity, 0 to 3; fraction, 0-10 % = 1, 11-50 % = 2, 51-80 % = 3, and >80 % = 4). The overall score was determined by multiplication of both scores and overall scores greater than 6 were considered FASN overexpression. On a component basis, FASN overexpression was detected in 8 % of seminomas but not in IGCNUs (0 %) and was detected frequently in non-seminomatous germ cell tumors (NSGCTs) (88 % of embryonal carcinomas, all choriocarcinomas, 81 % of yolk sac tumors, and 54 % of teratomas). There were no cases of a mixed tumor (i.e., a tumor with multiple histological components) that overexpressed FASN in seminoma components but not in co-existing NSGCT components, suggesting sequential progression. Our immunohistochemical data suggest that FASN overexpression occurs as a late event during the progression from IGCNUs/seminomas to NSGCTs.

Low- and high-grade bladder cancer determination via human serum-based metabolomics approach

To address the shortcomings of urine cytology and cystoscopy for probing and grading urinary bladder cancer (BC), we applied (1)H nuclear magnetic resonance (NMR) spectroscopy as a surrogate method for the identification of BC. This study includes 99 serum samples comprising low-grade (LG; n = 36) and high-grade (HG; n = 31) BC as well as healthy controls (HC; n = 32). (1)H NMR-derived serum data were analyzed using orthogonal partial least-squares discriminant analysis (OPLS-DA). OPLS-DA-derived model validity was confirmed using an internal and external cross-validation. Internal validation was performed using the initial samples (n = 99) data set. External validation was performed on a new batch of suspected BC patients (n = 106) through a double-blind study. Receiver operating characteristic (ROC) curve analysis was also performed. OPLS-DA-derived serum metabolomics (six biomarkers, ROC; 0.99) were able to discriminate 95% of BC cases with 96% sensitivity and 94% specificity when compared to HC. Likewise (three biomarkers, ROC; 0.99), 98% of cases of LG were able to differentiate from HG with 97% sensitivity and 99% specificity. External validation reveals comparable results to the internal validation. (1)H NMR-based serum metabolic screening appears to be a promising and less invasive approach for probing and grading BC in contrast to the highly invasive and painful cystoscopic approach for BC detection.

Microvesicles derived from human umbilical cord Wharton's jelly mesenchymal stem cells attenuate bladder tumor cell growth in vitro and in vivo

Several studies suggest that mesenchymal stem cells (MSCs) possess antitumor properties; however, the exact mechanisms remain unclear. Recently, microvesicles (MVs) are considered as a novel avenue intercellular communication, which may be a mediator in MSCs-related antitumor effect. In the present study, we evaluated whether MVs derived from human umbilical cord Wharton's jelly mesenchymal stem cells (hWJMSCs) may inhibit bladder tumor T24 cells growth using cell culture and the BALB/c nu/nu mice xenograft model. CCK-8 assay and Ki-67 immunostaining were performed to estimate cell proliferation in vitro and in vivo. Flow cytometry and TUNEL assay were used to assess cell cycle and apoptosis. To study the conceivable mechanism by which hWJMSC-MVs attenuate bladder tumor T24 cells, we estimated the expression of Akt/p-Akt, p-p53, p21 and cleaved Caspase 3 by Western blot technique after exposing T24 cells to hWJMSC-MVs for 24, 48 and 72h. Our data indicated that hWJMSC-MVs can inhibit T24 cells proliferative viability via cell cycle arrest and induce apoptosis in T24 cells in vitro and in vivo. This study showed that hWJMSC-MVs down-regulated phosphorylation of Akt protein kinase and up-regulated cleaved Caspase 3 during the process of anti-proliferation and pro-apoptosis in T24 cells. These results demonstrate that hWJMSC-MVs play a vital role in hWJMSC-induced antitumor effect and may be a novel tool for cancer therapy as a new mechanism of cell-to-cell communication.

Fatty acid synthase overexpression confers an independent prognosticator and associates with radiation resistance in nasopharyngeal carcinoma

Fatty acid synthase (FASN) is overexpressed in many human cancers and associated with poor prognosis. However, the role of FASN in nasopharyngeal carcinoma (NPC) has not been studied. We evaluated the expression of FASN immunohistochemically in 124 NPC specimens, stratified them into two groups (FASN-high and FASN-low), and examined the correlation with various clinicopathological parameters. In two NPC cell lines, HONE1 and TW01, we targeted the FASN transcript by shRNAi and evaluated the effect on cell proliferation by WST-1 assay and radiation-induced apoptosis by measuring caspase-3 and caspase-7 activation. NPC with high FASN immunoexpression was correlated with advanced pT disease status and worse prognosis in terms of disease-specific survival, metastasis-free survival and local recurrence-free survival, compared to FASN-low group in both univariate and multivariate analyses. In the two NPC cell lines, endogenous FASN expression was significantly higher than the non-tumor keratinocyte, DOK. When the expression of FASN was suppressed by shRNAi, the tumor cells showed decreased cell proliferation and increased apoptosis after radiation. Our results supported FASN as an adverse prognostic marker in NPC, possibly by conferring cell growth advantage and resistance to radiation-induced apoptosis on tumor cells. The inhibition of FASN expression might be investigated as an adjunct in treatment, especially in radiation resistant NPC.

Fatty acid synthase regulates proliferation and migration of colorectal cancer cells via HER2-PI3K/Akt signaling pathway

Recent evidence suggests that fatty acid synthase mediating de novo fatty acid synthesis plays a crucial role in the carcinogenesis process of various cancers. Moreover, HER2 and related PI3K/Akt signaling pathway, which links intimately with cellular metabolism, influence cancer biological behavior. However, it remains unknown whether malignant phenotype of colorectal cancer cells is regulated by the HER2-PI3K/Akt-FASN signaling pathway. In this study, Caco-2 cells were selected for functional characterization, and treated with ZSTK474, followed by RT-qPCR and Western blot assays examining PI3K, Akt, HER2, and FASN expression. The MTT and colony formation assays were used to assess proliferation. The migration was investigated by transwell, apoptosis, and cell-cycle analysis. We found that the blockade of PI3K/Akt signaling pathway by ZSTK474 treatment led to downregulation of PI3K, Akt, HER2, and FASN expression. The proliferation was decreased upon treatment which was consistent with an increased percentage of G(1) arrested cells instead of apoptosis. The migration of Caco-2 cells was also impaired by ZSTK474 treatment. Inhibition of HER2-PI3K/Akt signaling pathway suppresses FASN expression of Caco-2 cells, and inhibition of FASN expression changes malignant phenotype of Caco-2 cells.

The ubiquitin-specific protease USP2a enhances tumor progression by targeting cyclin A1 in bladder cancer

The deubiquitinating enzyme USP2a has shown oncogenic properties in many cancer types by impairing ubiquitination of FASN, MDM2, MDMX or Aurora A. Aberrant expression of USP2a has been linked to progression of human tumors, particularly prostate cancer. However, little is known about the role of USP2a or its mechanism of action in bladder cancer. Here, we provide evidence that USP2a is an oncoprotein in bladder cancer cells. Enforced expression of USP2a caused enhanced proliferation, invasion, migration and resistance to several chemotherapeutic reagents, while USP2a loss resulted in slower proliferation, greater chemosensitivity and reduced migratory/invasive capability compared with control cells. USP2a, but not a catalytically inactive mutant, enhanced proliferation in immortalized TRT-HU1 normal human bladder epithelial cells. USP2a bound to cyclin A1 and prevented cyclin A1 ubiquitination, leading to accumulation of cyclin A1 by a block in degradation. Enforced expression of wild type USP2a, but not an inactive USP2a mutant, resulted in cyclin A1 accumulation and increased cell proliferation. We conclude that USP2a impairs ubiquitination and stabilizes an important cell cycle regulator, cyclin A1, raising the possibility of USP2a targeting as a therapeutic strategy against bladder tumors in combination with chemotherapy.