A metabolite panel in combination with CA19-9, TIMP1, and LRG1 exhibited substantially improved performance in the detection of early-stage PDAC compared with a protein panel alone.
Glucagon-like peptide-1 (GLP-1) has the ability to lower the blood glucose level, and its regulatory functions make it an attractive therapeutic agent for the treatment of type 2 diabetes. However, its rapid degradation by enzymes like dipeptidyl peptidase-IV (DPP-IV) and neutral endopeptidase (NEP) 24.11 severely compromises its effective clinical use. Whereas specific DPP-IV inhibitors have been developed, NEP 24.11 targets multiple sites in the GLP-1 sequence, which makes it difficult to block. To address this drawback, we have designed and synthesized conformationally constrained GLP-1 analogues by introducing multiple lactam bridges that stabilized both alpha-helices in the N- and C-terminal regions simultaneously. In addition to improving the receptor activation capability (up to 5-fold) by fixing the alpha-helical conformations required for optimal receptor interaction, the introduced lactam bridges provided outstanding shielding over NEP 24.11 (half-life of >96 h). These highly constrained peptides are the first examples of NEP 24.11-resistant GLP-1 analogues.
Despite favorable responses to initial therapy, SCLC relapse occurs within a year exhibiting a multidrug resistant phenotype. Due to limited accessibility of patient tissues for research purpose, SCLC patient derived xenografts (PDXs) have provided the best opportunity to address this limitation. We sought to identify novel mechanisms involved in SCLC chemoresistance. Through in-depth proteomic profiling, we identified MCAM as a markedly upregulated surface receptor in chemoresistant SCLC cell lines that exhibited a mesenchymal phenotype and in chemoresistant PDXs compared to matched treatment-naïve tumors. MCAM is a cell membrane protein whose expression has been implicated in multiple human cancers. MCAM expression is also detected in lung adenocarcinoma; however, its expression and role in SCLC is has not been explored. MCAM knockdown in chemoresistant cells reduced cell proliferation and decreased the IC50 inhibitory concentration of chemotherapeutic drugs. MCAM was found to modulate sensitivity of SCLC cells to chemotherapeutic drugs through up-regulation of MRP1/ABCC1 expression and of the PI3/AKT pathway in a SOX2-dependent manner. Metabolomic profiling revealed that MCAM modulates lactate production in chemoresistant cells that exhibit a distinct metabolic phenotype characterized by low oxidative phosphorylation. MCAM may serve as a novel therapeutic target to overcome chemoresistance in SCLC.
Background MYC is an oncogenic driver of development and progression in triple-negative breast cancer (TNBC). Ornithine decarboxylase, the rate-limiting enzyme in polyamine metabolism, is a transcriptional target of MYC. We therefore hypothesized that a plasma polyamine signature may be predictive of TNBC development and progression. Methods Using liquid chromatography mass spectrometry, polyamine levels were determined in plasma samples from newly diagnosed patients with TNBC (n = 87) and cancer-free controls (n = 115). Findings were validated in plasma samples from an independent prospective cohort of 54 TNBC, 55 estrogen receptor negative (ER−) and progesterone receptor negative (PR−) and HER2 positive (HER2+), and 73 ER+ case patients, and 30 cancer-free control subjects. Gene expression data and clinical data for 921 and 2359 breast cancer tumors were obtained from The Cancer Genome Atlas repository and the Oncomine database, respectively. Relationships between plasma diacetylspermine (DAS) and tumor spermine synthase (SMS) mRNA expression with metastasis-free survival and overall survival were determined using Cox proportional hazard models; Fisher exact tests were used to assess risk of distant metastasis in relation to tumor SMS mRNA expression. Results An increase in plasma DAS, a catabolic product of spermine mediated through SMS, was observed in the TNBC subtype of breast cancer. Plasma levels of DAS in TNBC associated with increased risk of metastasis (plasma DAS value ≥ 1.16, hazard ratio = 3.06, 95% confidence interval [CI] = 1.15 to 8.13, two-sided P = .03). SMS mRNA expression in TNBC tumor tissue was also found to be predictive of poor overall survival (top 25th percentile hazard ratio = 2.06, 95% CI = 1.04 to 4.08, one-sided P = .04) and increased risk of distant metastasis in TNBC (comparison of lowest SMS quartile [reference] to highest SMS quartile relative risk = 1.90, 95% CI = 0.97 to 4.06, one-sided Fisher exact test P=.03). Conclusions Metabolomic profiling identified plasma DAS as a predictive marker for TNBC progression and metastasis.
Plasma and tumor caveolin-1 (Cav-1) are linked with disease progression in prostate cancer. Here we report that metabolomic profiling of longitudinal plasmas from a prospective cohort of 491 active surveillance (AS) participants indicates prominent elevations in plasma sphingolipids in AS progressors that, together with plasma Cav-1, yield a prognostic signature for disease progression. Mechanistic studies of the underlying tumor supportive oncometabolism reveal coordinated activities through which Cav-1 enables rewiring of cancer cell lipid metabolism towards a program of 1) exogenous sphingolipid scavenging independent of cholesterol, 2) increased cancer cell catabolism of sphingomyelins to ceramide derivatives and 3) altered ceramide metabolism that results in increased glycosphingolipid synthesis and efflux of Cav-1-sphingolipid particles containing mitochondrial proteins and lipids. We also demonstrate, using a prostate cancer syngeneic RM-9 mouse model and established cell lines, that this Cav-1-sphingolipid program evidences a metabolic vulnerability that is targetable to induce lethal mitophagy as an anti-tumor therapy.
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