acid-phosphatase and Glioblastoma

Glioblastoma multiforme is one of the most malignant types of cancer. This is mainly due to a cell subpopulation with an extremely aggressive potential, called glioblastoma stem-like cells (GSCs). These cells produce high levels of extracellular adenosine which has been associated with increased chemoresistance, migration, and invasion in glioblastoma. In this study, we attempted to elucidate the mechanisms that control extracellular adenosine levels in GSC subtypes. By using primary and U87MG-derived GSCs, we associated increased extracellular adenosine with the mesenchymal phenotype. [

Topics: 5'-Nucleotidase; Acid Phosphatase; Adenosine; Biological Transport; Brain Neoplasms; Cell Line, Tumor; Equilibrative Nucleoside Transporter 1; Extracellular Space; Glioblastoma; GPI-Linked Proteins; Humans; Neoplastic Stem Cells

Glioblastomas are lethal tumors characterized by malignant proliferation and recurrence promoted partly by glioblastoma stem cells (GSCs). GSCs are known to be regulated by hypoxia, but the mechanisms involved in this regulation are not fully understood. We now demonstrate that hypoxia-inducible factor HIF2α and prostatic acid phosphatase (PAP) are preferentially expressed in hypoxic GSCs in comparison with non-stem tumor cells and normal neural stem cells and that PAP is regulated by HIF2α. Targeting PAP in hypoxic GSCs inhibits self-renewal and proliferation in vitro and attenuates tumor initiation potential of GSCs in vivo. Using specific adenosine receptor antagonists, we further find that the pro-proliferative role of PAP is stemmed from stimulated A2B adenosine receptors. Moreover, selective blockage of A2B receptor or knockdown of PAP or A2B on hypoxic GSCs results in significant reduction of phosphorylation of Akt and Erk-1/2. Our results demonstrate that PAP may play a pro-proliferative role in hypoxic GSCs with a HIF2α-induction pattern, which may be ascribed to stimulated A2B receptors and activated Akt and Erk-1/2 pathways. Therefore, we propose that these identified molecular regulators of GSCs in the hypoxic niche might represent promising targets for antiglioblastoma therapies.

Topics: Acid Phosphatase; Adenosine; Adenosine A2 Receptor Antagonists; Animals; Basic Helix-Loop-Helix Transcription Factors; Blotting, Western; Cell Hypoxia; Cell Line, Tumor; Cell Proliferation; Cells, Cultured; Extracellular Signal-Regulated MAP Kinases; Female; Glioblastoma; Humans; Male; Neoplastic Stem Cells; Phosphorylation; Protein Tyrosine Phosphatases; Proto-Oncogene Proteins c-akt; Rats; Rats, Nude; Receptor, Adenosine A2B; RNA Interference; Tumor Cells, Cultured; Xanthines; Xenograft Model Antitumor Assays

Aberrations of genes/proteins regulating cell cycle and growth, increased proliferation and telomerase activity (TA) are documentable in glioblastoma multiforme. TA is more frequently detectable in secondary glioblastoma, which is also characterized by p53 mutation/overexpression. Discordant telomere (Te) length values have been reported in glioblastomas with and without TA. In 31 glioblastomas, in which pre-existing astrocytoma was not documented, we compared cases with and without TA for the expression of p53, EGFR, c-Myc, MIB-1 and Topoisomerase IIalpha; p53 mutations were also investigated by SSCP-PCR. Correlations were made with Te parameters [TePs: number (TeNo), length and area] as evaluated by image analysis in interphase nuclei of fluorescence in situ hybridization (FISH)-processed sections. We found no differences in the expression of the proteins evaluated and in TePs, except Te/nuclear area %, which was significantly lower in TA+ cases (p=0.02). TePs were, instead, inversely correlated with TA (p=0.0001). TA was positively correlated with MIB1 staining index in the TA+ cases (p=0.033), which also showed a positive correlation between TeNo and EGFR expression (p=0.042), and a trend towards a negative correlation between TeNo and p53 expression (p=0.05). Tumors overexpressing EGFR had a significantly shorter lifetime (p=0.0001). TeNo seems to be inversely correlated to tumor proliferation and lifetime in glioblastoma multiforme.

Topics: Acid Phosphatase; Adolescent; Adult; Antigens, Neoplasm; Brain Neoplasms; Cell Division; Child; DNA Topoisomerases, Type II; DNA-Binding Proteins; ErbB Receptors; Glioblastoma; Humans; Image Processing, Computer-Assisted; In Situ Hybridization, Fluorescence; Isoenzymes; Ki-67 Antigen; Middle Aged; Polymorphism, Single-Stranded Conformational; Proto-Oncogene Proteins c-myc; Tartrate-Resistant Acid Phosphatase; Telomerase; Telomere; Tumor Suppressor Protein p53

Lymphokine-activated killer (LAK) cells can kill several tumor cells. Their killing activity is generally due to cell-cell adhesion. Cell-cell adhesion of the LAK cells to the target cells is essential for LAK lysis. In this report, however, we describe that the LAK cells can also kill the target cells by cell-cell adhesion-independent killing. Killing occurred after the target cells were exposed to the LAK cells. When the LAK cells were added to glioblastoma cell lines T98G and U373MG (which proliferate by adhering to the bottom of a culture flask), the LAK cells killed them by cell-cell adhesion killing within 4 h (early killing). On the other hand, when small numbers of the LAK cells were added, some of the target cells escaped from the early killing. At 4 and 6 h after the adding the LAK cells, when the LAK cells were discarded from the flask by washing with PBS, the escaped cells still adhered and were alive. However, they ultimately died over the next 24-96 h (late killing). The late killing was the cell-cell adhesion-independent killing, because it occurred after the LAK cells were removed. In this killing, numerous granules and vacuoles appeared in the cytoplasm of the cells. The vacuoles enlarged and then the cells died. The cell death was different from apoptosis, because the nucleus was intact until the late stage and no DNA fragment laddering in the degenerated cells was recognized. The vacuoles were stained with acid phosphatase and the cell death was inhibited with 3-methyladenine (an inhibitor of lysosome), suggesting that the late killing may be autophagic cell death due to activated lysosome. Induction of late killing in tumor cells using the LAK cells may become one approach for cancer therapy.

Topics: Acid Phosphatase; Adenine; Apoptosis; Cell Adhesion; Cell Membrane; Cells, Cultured; Dose-Response Relationship, Drug; Glioblastoma; Humans; Killer Cells, Lymphokine-Activated; Lysosomes; Microscopy, Electron; Time Factors; Tumor Cells, Cultured

The frequency, distribution and size of coated pits along the upper and lower cell surfaces, and the cytoplasmic volume density of secondary lysosomes were studied by ultrastructural stereological methods in sparse and post-confluent cell cultures of a human normal glial line and a human malignant glioma line. Neither the frequency of coated pits nor the volume density of secondary lysosomes showed any statistically significant changes between the normal glial cells at 2 and 14 days after subcultivation. The numerical surface density of the coated pits was significantly higher along the lower cell surface than on the upper free surface. The coated pits on the malignant glioma cells at 14 days were far more frequent than at 2 days after subcultivation, or than on the sparse and post-confluent glial cells. The surface density of the coated pits was higher along the upper free cell surface than on the lower surface of the glioma cells, in contrast to the glial cells. The volume density of lysosomes was significantly higher in the post-confluent glioma cells than in the sparse cells. The mean diameter of the coated pit openings on cells at 2 days after subcultivation was significantly larger than at 14 days, both in the glial and glioma cell cultures. The observed differences in frequency and distribution of coated pits between the glial and glioma cells may reflect differences in receptor-mediated endocytosis and be related to the different growth characteristics of the normal and malignant cells. The greatly increased load of secondary lysosomes in post-confluent cultures of the glioma cells, in contrast to the glial cells, may be due to a higher rate of autophagocytosis in the malignant cells. The larger size of the coated pit openings on isolated than on post-confluent cells may reflect differences in surface properties between sparse and dense cells.

Topics: Acid Phosphatase; Cell Line; Coated Pits, Cell-Membrane; Endosomes; Glioblastoma; Humans; Interphase; Lysosomes; Microscopy, Electron, Scanning; Neuroglia

Purified plasma membranes were obtained from five transplantable human tumors, a grade IV astrocytoma, an oat cell carcinoma, and three melanomas. Plasma membrane fractions were isolated from tumor homogenates by differential and discontinuous sucrose gradient centrifugation. Determination of enzyme activities indicated that the plasma membranes were enriched 10- to 20-fold with respect to 5'-nucleotidase, nicotinamide adenine dinucleotide glycohydrolase, Mg2+-activated nucleoside triphosphatase, and sialic acid. Specific activities of nearly all the enzymes varied with the individual tumors, even among tumors of the same type, i.e., the melanomas. Electron micrographs of the plasma membrane fractions showed smooth single-membrane vesicles with slight contamination by lysosomes. Therefore, these membranes are suitable for comparative biochemical studies and for the preparation of tumor-specific monoclonal antibodies. Plasma membranes from all five tumors contained very high Mg2+-adenosine triphosphatase (ATPase) activities. The Na+-K+-ATPase was a minor component of the total ATPase of these membranes (less than 30%). The major component was an ATPase exhibiting similar activity toward several nucleoside triphosphates. The activity of such a nucleoside triphosphatase has been correlated with tumorigenicity in cultured liver epithelial cells. The nucleoside triphosphatase of the plasma membranes of astrocytoma and oat cell carcinoma was stimulated from 50 to 1005 by concanavalin A, whereas ATPase of the melanoma plasma membranes was not or only slightly stimulated. The different response to concanavalin A could be due to differences in the ATPase molecules of the individual tumors or to the different environment of the ATPase.

Topics: Acid Phosphatase; Adenosine Triphosphatases; Animals; Ca(2+) Mg(2+)-ATPase; Carcinoma, Small Cell; Cell Membrane; Glioblastoma; Humans; Melanoma; Mice; Mice, Nude; NAD+ Nucleosidase; NADH Dehydrogenase; Neoplasm Transplantation; Neoplasms, Experimental; Nucleotidases; Sialic Acids; Transplantation, Heterologous

Topics: Acid Phosphatase; Adult; Brain Neoplasms; Central Nervous System Diseases; Cerebrospinal Fluid; Child, Preschool; Epilepsy; Female; Glioblastoma; Humans; Hypersensitivity; Inflammation; Lymphoma, Large B-Cell, Diffuse; Lysosomes; Male; Mental Disorders; Neurotic Disorders; Peptide Hydrolases; Psychotic Disorders; Vascular Diseases

Topics: Acid Phosphatase; Animals; Astrocytoma; Brain Neoplasms; Cells, Cultured; Culture Techniques; Ependymoma; Glioblastoma; Glioma; Glucosephosphate Dehydrogenase; L-Lactate Dehydrogenase; Mice; Mice, Inbred C3H; Neoplasms, Experimental; Succinate Dehydrogenase

Topics: Acid Phosphatase; Adenoma, Chromophobe; Astrocytoma; Biopsy; Brain Neoplasms; Choroid Plexus; Ependymoma; Glioblastoma; Hemangiosarcoma; Histocytochemistry; Humans; Medulloblastoma; Meningioma; Neurilemmoma; Oligodendroglioma; Papilloma; Pituitary Neoplasms; Rosaniline Dyes; Sarcoma; Staining and Labeling

Topics: Acid Phosphatase; Adenoma, Chromophobe; Adenosine Triphosphatases; Alkaline Phosphatase; Brain Neoplasms; Glioblastoma; Histocytochemistry; Humans; Meningioma; Neurilemmoma; Peripheral Nervous System Neoplasms; Pituitary Neoplasms; Succinate Dehydrogenase; Vestibulocochlear Nerve

Topics: Acid Phosphatase; Animals; Esterases; Glioblastoma; Glycoside Hydrolases; Histocytochemistry; L-Lactate Dehydrogenase; Neoplasms, Experimental; Rabbits

Topics: Acid Phosphatase; Astrocytoma; Brain Chemistry; Brain Neoplasms; Cytoplasm; Ependymoma; Esterases; Glioblastoma; Histocytochemistry; Humans; Lymphoma, Large B-Cell, Diffuse; Medulloblastoma; Neoplasm Metastasis; Neurilemmoma; Phosphates; Physostigmine

Topics: Acid Phosphatase; Adenosine Triphosphate; Alkaline Phosphatase; Astrocytoma; Brain; Brain Neoplasms; Cerebellar Neoplasms; Dihydrolipoamide Dehydrogenase; Electron Transport Complex II; Ependyma; Esterases; Glioblastoma; Glucose-6-Phosphatase; Hemangiosarcoma; Histocytochemistry; Intracranial Arteriosclerosis; L-Lactate Dehydrogenase; NAD; NADP; Oligodendroglioma; Succinate Dehydrogenase

Topics: Acid Phosphatase; Alkaline Phosphatase; Astrocytoma; Brain; Brain Neoplasms; Esterases; Glioblastoma; Glioma; NAD; NADP; Neurochemistry; Oligodendroglioma; Oxidoreductases