Malignant gliomas aggressively invade the surrounding normal brain, whereas brain metastases of nonglial tumors do not. The invasive behavior of gliomas may be mediated by tissue- or tumor-specific extracellular proteins. mRNA for the brain-specific extracellular brain enriched hyaluronan-binding protein (BEHAB) is not detectable in normal adult human cortex or in any nonglioma tumor examined. BEHAB is consistently expressed in surgical samples of glioma (n = 27). Glioma cell lines maintained under standard cell culture conditions or grown as s.c. tumors do not express BEHAB. When grown as intracranial grafts, glioma cell lines that invade the brain express BEHAB, whereas noninvasive cell lines do not. BEHAB is a unique and selective marker for glioma and may play a role in tumor invasion.
Abstract Glioma, the most common primary brain tumor of the adult central nervous system, is associated with a poor prognosis due, in part, to the presence of chemoradiotherapy-resistant glioma stem-like cells responsible for inevitable post-surgical recurrence. N-acetyl-L-aspartate (NAA), one of the most concentrated metabolic sources of acetate in the brain, and aspartoacylase (ASPA), the enzyme responsible for NAA degradation, are significantly reduced in glioma tumors. NAA-derived acetate is converted to acetyl coenzyme A via acetyl-CoA synthetase (AceCS) for use in lipogenesis, protein/histone acetylation, and the TCA cycle. We propose that glyceryltriacetate (GTA), a FDA approved food additive with “generally regarded as safe” status, may be an effective means of reducing glioma growth via restoration of acetate levels. The effect of GTA on the growth of both established (Hs683, HOG) and stem-like (grade II OG33, grade III OG35) oligodendroglioma cell lines was assessed. In vitro, GTA induced growth arrest in all cells examined (i.e., increased proportion of cells in G0/G1 and reduced S phase cells by flow cytometry of propidium iodide labeled cells 24 hours after treatment and unbiased trypan blue exclusion based cytometry up to 5 days post-treatment). Growth arrest was not associated with apoptosis (lack of cleaved poly ADP-ribose polymerase immunolabeling), but differentiation (increased CNPase expression). ASPA expression was greater in stem-like cells when grown in stem cell media than differentiation media and was decreased in GTA-treated OG35 cells. Interestingly, GTA did not decrease ASPA expression in OG33 cells, but induced a novel 26 kDa ASPA isoform. ASPA and AceCS1 were co-localized within the nucleus. Nuclear, but not cytosolic, ASPA expression was decreased upon GTA addition in stem cell media, but not differentiation media. Finally, the effect of GTA on orthotopically grafted luciferase expressing OG33 and OG35 cells was assessed. Bioluminescence and tumor volume were reduced in GTA treated mice. These data suggest that the nuclear ASPA/AceCS1 co-localization provides acetate for histone acetylation to maintain cells in a progenitor/stem-like state and that decreased ASPA promotes gliomagenesis. Inasmuch as infants with Canavan Disease, a leukodystrophy due to ASPA mutation, treated with high dose GTA showed no significant side effects, GTA may prove an effective therapy to prevent recurrence by inducing growth arrest/differentiation of glioma stem-like cells. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3481. doi:1538-7445.AM2012-3481
Acetate is a major end product of bacterial fermentation of fiber in the gut. Acetate, whether derived from the diet or from fermentation in the colon, has been implicated in a range of health benefits. Acetate is also generated in and released from various tissues including the intestine and liver, and is generated within all cells by deacetylation reactions. To be utilized, all acetate, regardless of the source, must be converted to acetyl coenzyme A (acetyl-CoA), which is carried out by enzymes known as acyl-CoA short-chain synthetases. Acyl-CoA short-chain synthetase-2 (ACSS2) is present in the cytosol and nuclei of many cell types, whereas ACSS1 is mitochondrial, with greatest expression in heart, skeletal muscle, and brown adipose tissue. In addition to acting to redistribute carbon systemically like a ketone body, acetate is becoming recognized as a cellular regulatory molecule with diverse functions beyond the formation of acetyl-CoA for energy derivation and lipogenesis. Acetate acts, in part, as a metabolic sensor linking nutrient balance and cellular stress responses with gene transcription and the regulation of protein function. ACSS2 is an important task-switching component of this sensory system wherein nutrient deprivation, hypoxia and other stressors shift ACSS2 from a lipogenic role in the cytoplasm to a regulatory role in the cell nucleus. Protein acetylation is a critical post-translational modification involved in regulating cell behavior, and alterations in protein acetylation status have been linked to multiple disease states, including cancer. Improving our fundamental understanding of the “acetylome” and how acetate is generated and utilized at the subcellular level in different cell types will provide much needed insight into normal and neoplastic cellular metabolism and the epigenetic regulation of phenotypic expression under different physiological stressors.
Pulmonary diseases represent a large portion of neonatal and adult morbidity and mortality. Many of these have no cure, and new therapeutic approaches are desperately needed. De-cellularization of whole organs, which removes cellular elements but leaves intact important extracellular matrix (ECM) proteins and three-dimensional architecture, has recently been investigated for ex vivo generation of lung tissues. As specific cell culture surfaces, including ECM composition, profoundly affect cell differentiation, this approach offers a potential means of using de-cellularized lungs to direct differentiation of embryonic and other types of stem/progenitor cells into lung phenotypes. Several different methods of whole-lung de-cellularization have been reported, but the optimal method that will best support re-cellularization and generation of lung tissues from embryonic stem cells (ESCs) has not been determined. We present a 24-h approach for de-cellularizing mouse lungs utilizing a detergent-based (Triton-X100 and sodium deoxycholate) approach with maintenance of three-dimensional lung architecture and ECM protein composition. Predifferentiated murine ESCs (mESCs), with phenotypic characteristics of type II alveolar epithelial cells, were seeded into the de-cellularized lung scaffolds. Additionally, we evaluated the effect of coating the de-cellularized scaffold with either collagen or Matrigel to determine if this would enhance cell adhesion and affect mechanics of the scaffold. Finally, we subcutaneously implanted scaffolds in vivo after seeding them with mESCs that are predifferentiated to express pro-surfactant protein C (pro-SPC). The in vivo environment supported maintenance of the pro-SPC-expressing phenotype and further resulted in vascularization of the implant. We conclude that a rapid detergent-based de-cellularization approach results in a scaffold that can maintain phenotypic evidence of alveolar epithelial differentiation of ESCs and support neovascularization after in vivo implantation.
Retrospective studies on male breast cancer (MBC) have suff ered from small numbers of cases available from any one centre; thus a signifi cant problem in eff ectively studying this disease is accruing suffi ciently large numbers to allow comparative analysis of biomarkers associated with response.Using a coordinated multicentre approach, we present the fi rst large-scale study to address the relevance of the expression of hormone receptors in MBC and female breast cancer (FBC) using immunohistochemistry combined with a novel bioinformatics approach.Following ethical approval, 523 archival blocks (260 MBCs and 263 matched FBCs) were obtained retrospectively.Tissue microarrays were constructed and sections stained for ERα, ERβ1, ERβ2, ERβ5, total PR, PRA, PRB and AR and typed using CK5/6, CK14, CK18 and CK19 by immunohistochemistry. Following scoring, a range of ordination techniques were conducted on the datasets including hierarchical clustering and principal component analysis (PCA) to determine the diff erential nature of infl uences and interactions between MBC and FBC.Luminal A subgroup (ERα + and/or PR + , HER2 -) was the most common phenotype in both sexes.Luminal B (ERα + and/or PR + , HER2 + ) was not seen in males, while basal-like tumours (ERα -, PR -, HER2 -, CK5/6 + ) were infrequent in both.Hierarchical clustering revealed common clusters between MBC and FBC including total PR-PRA-PRB and ERβ1/2 clusters.ERα occurred on distinct clusters between males and females.AR, ERβ1, ERβ2 and ERβ5 all existed on the same cluster but with a diff erent substructure, particularly around the positioning of AR.ERα associated with this cluster in the male but not the female group.PCA confi rmed that in both groups strong infl uences came from PR-PRA-PRB.In MBC strong infl uences additionally came from AR and ERβ1, ERβ2 and ERβ5, whereas in FBC strong infl uences came from ERα alone.Our data support the hypothesis that breast cancer is biologically diff erent in male and females, which could have implications for therapy. O2
Although traditionally recognized for maintaining extracellular matrix integrity during morphogenesis, the function of matrix metallo-proteinases (MMPs) and their inhibitors, the tissue inhibitors of metalloproteinases (TIMPs), in the mature nervous system is essentially unknown. Here, we report that TIMP-2 induces pheochromocytoma PC12 cell-cycle arrest via regulation of cell-cycle regulatory proteins, resulting in differentiation and neurite outgrowth. TIMP-2 decreases cyclins B and D expression and increases p21 Cip expression. Furthermore, TIMP-2 promotes cell differentiation via activation of the cAMP/Rap1/ERK (extracellular signal-regulated kinase) pathway. Expression of dominant-negative Rap1 blocks TIMP-2-mediated neurite outgrowth. Both the cell-cycle arrest and neurite outgrowth induced by TIMP-2 was independent of MMP inhibitory activity. Consistent with the PC12 cell data, primary cultures of TIMP-2 knock-out cerebral cortical neurons exhibit significantly reduced neurite length, which is rescued by TIMP-2. These in vitro results were corroborated in vivo . TIMP-2 deletion causes a delay in neuronal differentiation, as demonstrated by the persistence of nestin-positive progenitors in the neocortical ventricular zone. The interaction of TIMP-2 with α3β1 integrin in the cerebral cortex suggests that TIMP-2 promotes neuronal differentiation and maintains mitotic quiescence in an MMP-independent manner through integrin activation. The identification of molecules responsible for neuronal quiescence has significant implications for the ability of the adult brain to generate new neurons in response to injury and neurological disorders, such as Alzheimer's and Parkinson's diseases.
Recellularization of whole decellularized lung scaffolds provides a novel approach for generating functional lung tissue ex vivo for subsequent clinical transplantation. To explore the potential utility of stem and progenitor cells in this model, we investigated recellularization of decellularized whole mouse lungs after intratracheal inoculation of bone marrow-derived mesenchymal stromal cells (MSCs). The decellularized lungs maintained structural features of native lungs, including intact vasculature, ability to undergo ventilation, and an extracellular matrix (ECM) scaffold consisting primarily of collagens I and IV, laminin, and fibronectin. However, even in the absence of intact cells or nuclei, a number of cell-associated (non-ECM) proteins were detected using mass spectroscopy, western blots, and immunohistochemistry. MSCs initially homed and engrafted to regions enriched in types I and IV collagen, laminin, and fibronectin, and subsequently proliferated and migrated toward regions enriched in types I and IV collagen and laminin but not provisional matrix (fibronectin). MSCs cultured for up to 1 month in either basal MSC medium or in a small airways growth media (SAGM) localized in both parenchymal and airway regions and demonstrated several different morphologies. However, while MSCs cultured in basal medium increased in number, MSCs cultured in SAGM decreased in number over 1 month. Under both media conditions, the MSCs predominantly expressed genes consistent with mesenchymal and osteoblast phenotype. Despite a transient expression of the lung precursor TTF-1, no other airway or alveolar genes or vascular genes were expressed. These studies highlight the power of whole decellularized lung scaffolds to study functional recellularization with MSCs and other cells.
