Coupling of Glucose Deprivation with Impaired Histone H2B Monoubiquitination in Tumors

Metabolic reprogramming is associated with tumorigenesis. However, glucose metabolism in tumors is poorly understood. Here, we report that glucose levels are significantly lower in bulk tumor specimens than those in normal tissues of the same tissue origins. We show that mono-ubiquitinated histone H2B (uH2B) is a semi-quantitative histone marker for glucose. We further show that loss of uH2B occurs specifically in cancer cells from a wide array of tumor specimens of breast, colon, lung and additional 23 anatomic sites. In contrast, uH2B levels remain high in stromal tissues or non-cancerous cells in the tumor specimens. Taken together, our data suggest that glucose deficiency and loss of uH2B are novel properties of cancer cells in vivo, which may represent important regulatory mechanisms of tumorigenesis

Metabolism of tumors under treatment: mapping of metabolites with quantitative bioluminescence

Background and purpose: The metabolic switch to aerobic glycolysis (Warburg effect) and enhanced lactate production is characteristic for aggressive tumor cells and is a co-determining factor for tumor response and treatment outcome. Thus analysis of the metabolic status under treatment is important to understand and improve treatment modalities. Materials and methods: Metabolite concentrations were determined by the immersion of tumor sections in an ATP, lactate or glucose-depending luciferase-containing buffer system. Integrated light output is detected in a bioluminescent detection system. Results: Mice carrying tumor xenografts derived from A549 lung cancer cells were treated with the microtubule stabilizing agent patupilone, ionizing radiation or in combination. Lactate levels were significantly reduced and glucose levels drastically increased in comparison to untreated tumors. Interestingly, these changes were only minimal in tumors derived from patupilone-resistant but otherwise isogenic A549EpoB40 cells. ATP levels of all tumors tested did not change under any treatment. When compared with histological endpoints, basal and treatment-dependent changes of lactate levels in the different tumors mainly correlated with the proliferative activity and the tumor growth response to treatment. Conclusions: This study shows that the tumor metabolism is responsive to different treatment modalities and could eventually be used as an early surrogate marker for treatment response

Antagonizing the hedgehog pathway with vismodegib impairs malignant pleural mesothelioma growth in vivo by affecting stroma

An autocrine driven upregulation of the Hedgehog (Hh) signaling pathway has been described in malignant pleural mesothelioma (MPM), in which the ligand, desert hedgehog (DHH), was produced from tumor cells. However, our investigation revealed that the Hh pathway is activated in both tumor and stroma of MPM tumor specimens and an orthotopic immunocompetent rat MPM model. This was demonstrated by positive immunohistochemical staining of Glioma associated oncogene 1 (GLI1) and Patched1 (PTCH1) in both tumor and stromal fractions. DHH was predominantly expressed in the tumor fractions. To further investigate the role of the Hh pathway in MPM stroma, we antagonized Hh signaling in the rat model of MPM using a Hh antagonist, vismodegib, (100 mg/kg peroral). Daily treatment with vismodegib efficiently downregulated Hh target genes, Gli1, Hedgehog Interacting Protein (Hhip) and Ptch1, and caused a significant reduction of tumor volume, and tumor growth delay. Immunohistochemical analyses revealed that vismodegib treatment primarily down regulated GLI1 and HHIP in the stromal compartment along with a reduced expression of previously described fibroblast Hh responsive genes such as Fibronectin (Fn1) and Vegf. Primary cells isolated from the rat model cultured in 3%O2 continued to express Dhh but did not respond to vismodegib in vitro. However, culture supernatant from these cells stimulated Gli1, Ptch1, and Fn1 expression in mouse embryonic fibroblasts which was suppressed by vismodegib. Our study provides new evidence regarding the role of Hh signaling in MPM stroma in the maintenance of tumor growth, emphasizing Hh signaling as a treatment target for MPM

Novel TIE-2 inhibitor BAY-826 displays in vivo efficacy in experimental syngeneic murine glioma models

Targeting the vascular endothelial growth factor signaling axis in glioblastoma inevitably leads to tumor recurrence and a more aggressive phenotype. Therefore, other angiogenic pathways, like the angiopoietin/tunica interna endothelial cell kinase (TIE) signaling axis, have become additional targets for therapeutic intervention. Here, we explored whether targeting the receptor tyrosine kinase TIE-2 using a novel, highly potent, orally available small molecule TIE-2 inhibitor (BAY-826) improves tumor control in syngeneic mouse glioma models. BAY-826 inhibits TIE-2 phosphorylation in vitro and in vivo as demonstrated by suppression of Angiopoietin-1- or Na3 VO4 -induced TIE-2 phosphorylation in glioma cells or extracts of lungs from BAY-826-treated mice. There was a trend toward prolonged survival upon single-agent treatment in two of four models (SMA-497 and SMA-540) and there was a significant survival benefit in one model (SMA-560). Co-treatment with BAY-826 and irradiation was ineffective in one model (SMA-497), but provided synergistic prolongation of survival in another (SMA-560). Decreased vessel densities and increased leukocyte infiltration were observed, but might be independent processes as the effect was also observed in single treatment modalities. These data demonstrate that TIE-2 inhibition may improve tumor response to treatment in highly vascularized tumors such as glioblastoma

A novel concept for scaffold-free vessel tissue engineering : self-assembly of microtissue building blocks

Current scientific attempts to generate in vitro tissue-engineered living blood vessels (TEBVs) show substantial limitations, thereby preventing routine clinical use. In the present report, we describe a novel biotechnology concept to create living small diameter TEBV based exclusively on microtissue self-assembly (living cellular re-aggregates). A novel bioreactor was designed to assemble microtissues in a vascular shape and apply pulsatile flow and circumferential mechanical stimulation. Microtissues composed of human artery-derived fibroblasts (HAFs) and endothelial cells (HUVECs) were accumulated and cultured for 7 and 14 days under pulsatile flow/mechanical stimulation or static culture conditions with a diameter of 3 mm and a wall thickness of 1 mm. The resulting vessels were analyzed by immunohistochemistry for extracellular matrix (ECM) and cell phenotype (von Willebrand factor, a-SMA, Ki67, VEGF). Self-assembled microtissues composed of fibroblasts displayed significantly accelerated ECM formation compared to monolayer cell sheets. Accumulation of vessel-like tissue occurred within 14 days under both, static and flow/mechanical stimulation conditions. A layered tissue formation was observed only in the dynamic group, as indicated by luminal aligned a-SMA positive fibroblasts. We could demonstrate that self-assembled cell-based microtissues can be used to generate small diameter TEBV. The significant enhancement of ECM expression and maturation, together with the pre-vascularization capacity makes this approach highly attractive in terms of generating functional small diameter TEBV devoid of any foreign material

A novel concept for scaffold-free vessel tissue engineering: self-assembly of microtissue building blocks

Current scientific attempts to generate in vitro tissue-engineered living blood vessels (TEBVs) show substantial limitations, thereby preventing routine clinical use. In the present report, we describe a novel biotechnology concept to create living small diameter TEBV based exclusively on microtissue self-assembly (living cellular re-aggregates). A novel bioreactor was designed to assemble microtissues in a vascular shape and apply pulsatile flow and circumferential mechanical stimulation. Microtissues composed of human artery-derived fibroblasts (HAFs) and endothelial cells (HUVECs) were accumulated and cultured for 7 and 14 days under pulsatile flow/mechanical stimulation or static culture conditions with a diameter of 3mm and a wall thickness of 1mm. The resulting vessels were analyzed by immunohistochemistry for extracellular matrix (ECM) and cell phenotype (von Willebrand factor, alpha-SMA, Ki67, VEGF). Self-assembled microtissues composed of fibroblasts displayed significantly accelerated ECM formation compared to monolayer cell sheets. Accumulation of vessel-like tissue occurred within 14 days under both, static and flow/mechanical stimulation conditions. A layered tissue formation was observed only in the dynamic group, as indicated by luminal aligned alpha-SMA positive fibroblasts. We could demonstrate that self-assembled cell-based microtissues can be used to generate small diameter TEBV. The significant enhancement of ECM expression and maturation, together with the pre-vascularization capacity makes this approach highly attractive in terms of generating functional small diameter TEBV devoid of any foreign material