Background:Docetaxel is the first-line chemotherapy for castration-resistant prostate cancer (CRPC). However, response rates are ∼50% and determined quite late in the treatment schedule, thus non-responders are subjected to unnecessary toxicity. The potential of circulating microRNAs as early biomarkers of docetaxel response in CRPC patients was investigated in this study.Methods:Global microRNA profiling was performed on docetaxel-resistant and sensitive cell lines to identify candidate circulating microRNA biomarkers. Custom Taqman Array MicroRNA cards were used to measure the levels of 46 candidate microRNAs in plasma/serum samples, collected before and after docetaxel treatment, from 97 CRPC patients.Results:Fourteen microRNAs were associated with serum prostate-specific antigen (PSA) response or overall survival, according to Mann–Whitney U or log-rank tests. Non-responders to docetaxel and patients with shorter survival generally had high pre-docetaxel levels of miR-200 family members or decreased/unchanged post-docetaxel levels of miR-17 family members. Multivariate Cox regression with bootstrapping validation showed that pre-docetaxel miR-200b levels, post-docetaxel change in miR-20a levels, pre-docetaxel haemoglobin levels and visceral metastasis were independent predictors of overall survival when modelled together.Conclusions:Our study suggests that circulating microRNAs are potential early predictors of docetaxel chemotherapy outcome, and warrant further investigation in clinical trials.

Lipids are known to influence tumour growth, inflammation and chemoresistance. However, the association of circulating lipids with the clinical outcome of metastatic castration-resistant prostate cancer (CRPC) is unknown. We investigated associations between the plasma lipidome and clinical outcome in CRPC. Lipidomic profiling by liquid chromatography-tandem mass spectrometry was performed on plasma samples from a Phase 1 discovery cohort of 96 CRPC patients. Results were validated in an independent Phase 2 cohort of 63 CRPC patients. Unsupervised analysis of lipidomic profiles (323 lipid species) classified the Phase 1 cohort into two patient subgroups with significant survival differences (HR 2.31, 95% CI 1.44-3.68, p = 0.0005). The levels of 46 lipids were individually prognostic and were predominantly sphingolipids with higher levels associated with poor prognosis. A prognostic three-lipid signature was derived (ceramide d18:1/24:1, sphingomyelin d18:2/16:0, phosphatidylcholine 16:0/16:0) and was also associated with shorter survival in the Phase 2 cohort (HR 4.8, 95% CI 2.06-11.1, p = 0.0003). The signature was an independent prognostic factor when modelled with clinicopathological factors or metabolic characteristics. The association of plasma lipids with CRPC prognosis suggests a possible role of these lipids in disease progression. Further research is required to determine if therapeutic modulation of the levels of these lipids by targeting their metabolic pathways may improve patient outcome.

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Prostate cancer cells exhibit altered cellular metabolism but, notably, not the hallmarks of Warburg metabolism. Prostate cancer cells exhibit increased de novo synthesis of fatty acids (FA); however, little is known about how extracellular FAs, such as those in the circulation, may support prostate cancer progression. Here, we show that increasing FA availability increased intracellular triacylglycerol content in cultured patient-derived tumor explants, LNCaP and C4-2B spheroids, a range of prostate cancer cells (LNCaP, C4-2B, 22Rv1, PC-3), and prostate epithelial cells (PNT1). Extracellular FAs are the major source ($83%) of carbons to the total lipid pool in all cell lines, compared with glucose ($13%) and glutamine ($4%), and FA oxidation rates are greater in prostate cancer cells compared with PNT1 cells, which preferentially partitioned extracellular FAs into triacylglycerols. Because of the higher rates of FA oxidation in C4-2B cells, cells remained viable when challenged by the addition of palmitate to culture media and inhibition of mitochondrial FA oxidation sensitized C4-2B cells to palmitate-induced apoptosis. Whereas in PC-3 cells, palmitate induced apoptosis, which was prevented by pretreatment of PC-3 cells with FAs, and this protective effect required DGAT-1-mediated triacylglycerol synthesis. These outcomes highlight for the first-time heterogeneity of lipid metabolism in prostate cancer cells and the potential influence that obesity-associated dyslipidemia or host circulating has on prostate cancer progression.Implications: Extracellular-derived FAs are primary building blocks for complex lipids and heterogeneity in FA metabolism exists in prostate cancer that can influence tumor cell behavior.

Interleukin-10 is an immunosuppressive cytokine involved in the regulation of gastrointestinal mucosal immunity toward intestinal microbiota. Interleukin-10-deficient (IL10(-/-)) mice develop Crohn's disease-like colitis unless raised in germ-free conditions. Previous gas chromatography-mass spectrometry (GC-MS) metabolomic analysis revealed urinary metabolite differences between IL10(-/-) and wildtype C57BL/6 mice. To determine which of these differences were specifically associated with intestinal inflammation arising from IL10-deficiency, urine samples from IL10(-/-) and wildtype mice, housed in either conventional or specific pathogen-free conditions, were subjected to GC-MS metabolomic analysis. Fifteen metabolite differences, including fucose, xanthurenic acid, and 5-aminovaleric acid, were associated with intestinal inflammation. Elevated urinary levels of xanthurenic acid in IL10(-/-) mice were attributed to increased production of kynurenine metabolites that may induce T-cell tolerance toward intestinal microbiota. Liquid chromatography-mass spectrometry analysis confirmed that plasma levels of kynurenine and 3-hydroxykynurenine were elevated in IL10(-/-) mice. Eleven metabolite differences, including glutaric acid, 2-hydroxyglutaric acid, and 2-hydroxyadipic acid, were unaffected by the severity of inflammation. These metabolite differences may be associated with residual genes from the embryonic stem cells of the 129P2 mouse strain that were used to create the IL10(-/-) mouse, or may indicate novel functions of IL10 unrelated to inflammation.

Crohn's disease is an inflammatory disorder of the bowel, believed to arise from the dysregulation of intestinal mucosal immunity. The interleukin-10-deficient (IL10-/-) mouse, which develops intestinal inflammation in the presence of gut microflora, serves as a mouse model of Crohn's disease. Nontargeted urinary metabolite profiling was carried out to identify systemic metabolic changes associated with the development of intestinal inflammation caused by IL10-deficiency. Spot urine samples, collected from IL10-/- and wildtype mice at ages 5.5, 7, 8.5, and 10.5 weeks old were analyzed by gas chromatography-mass spectrometry (GCMS). The data were analyzed using XCMS software, multiple t tests, and ANOVA. Among the key metabolic differences detected were elevated urinary levels of xanthurenic acid and fucose in IL10-/- mice relative to wildtype, indicating upregulation of tryptophan catabolism and perturbed fucosylation in IL10-/- mice. Three short-chain dicarboxylic acid metabolites were decreased in urine of IL10-/- mice relative to wildtype, suggesting the downregulation of fatty acid oxidation in IL10-/- mice. These metabolic differences were reproducible in an independent set of mice. This study demonstrates that nontargeted GCMS metabolite profiling of IL10-/- mice can provide insights into the metabolic effects of IL10-deficiency and identify potential markers of intestinal inflammation.

Background:Biomarkers of therapeutic response and prognosis are needed to assist in the sequencing of treatments for metastatic castration-resistant prostate cancer (CRPC). Previously in a Phase 1 discovery study, we identified 14 circulating microRNAs that were associated with response to docetaxel chemotherapy or overall survival. We performed a Phase 2 validation study to verify these findings.Methods:Using real-time PCR, the levels of the 14 microRNAs were measured in plasma collected before and after the first cycle of docetaxel from a Phase 2 cohort of 89 patients.Results:The microRNAs were not associated with docetaxel response in the Phase 2 cohort. Higher baseline levels of six microRNAs, predominantly of the miR-200 family, were confirmed to be associated with shorter overall survival. A microRNA signature comprising these six microRNAs predicted high-risk patients in the Phase 2 cohort with a hazard ratio of 4.12 (95% CI 2.20–7.70, P=0.000001). The signature was an independent predictor in multivariable analysis with clinicopathological factors.Conclusions:The association of circulating microRNAs with overall survival suggests their involvement in CRPC progression.

Crohn's disease (CD) and ulcerative colitis (UC) are inflammatory bowel diseases (IBD) attributed to a dysregulated immune response towards intestinal microbiota. Although various susceptibility genes have been identified for CD and UC, the exact disease etiology is unclear and complicated by the influence of environmental factors. Metabolomic analysis enables high sample throughput measurements of multiple metabolites in biological samples. The use of metabolomic analysis in medical sciences has revealed metabolite perturbations associated with diseases. This article provides a summary of the current understanding of IBD, and describes potential applications and previous metabolomic analysis in IBD research to understand IBD pathogenesis and improve IBD therapy.