tetracycline and Glioblastoma

We present an image of a patient's skull characterized by dark, irregular discoloration. This was discovered incidentally in a 66-year-old man who underwent craniotomy for resection of a glioblastoma. This image demonstrates cranial black bone disease. This is an abnormal bone pigmentation associated with long-term tetracycline use, as occurred in this patient.

Topics: Aged; Anti-Bacterial Agents; Bone Diseases; Craniotomy; Glioblastoma; Humans; Male; Skull; Tetracycline; Time; Tomography, X-Ray Computed

The brain tumor glioblastoma (GBM) remains one of the most aggressive and devastating tumors despite decades of effort to find more effective treatments. A hallmark of GBM is the constitutive activation of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kappaB) signaling pathway, which regulates cell proliferation, inflammation, migration and apoptosis. The prolyl isomerase, Pin1, has been found to bind directly to the NF-kappaB protein, p65, and cause increases in NF-kappaB promoter activity in a breast cancer model. We now present evidence that this interaction occurs in GBM and that it has important consequences on NF-kappaB signaling. We demonstrate that Pin1 levels are enhanced in primary GBM tissues compared with controls, and that this difference in Pin1 expression affects the migratory capacity of GBM-derived cells. Pin1 knockdown decreases the amount of activated, phosphorylated p65 in the nucleus, resulting in inhibition of the transcriptional program of the IL-8 gene. Through the use of microarray, we also observed changes in the expression levels of other NF-kappaB regulated genes due to Pin1 knockdown. Taken together, these data suggest that Pin1 is an important regulator of NF-kappaB in GBM, and support the notion of using Pin1 as a therapeutic target in the future.

Topics: Animals; Brain Neoplasms; Cell Line, Tumor; Cell Movement; Gene Expression Regulation, Neoplastic; Gene Knockdown Techniques; Glioblastoma; Humans; Interleukin-8; Inverted Repeat Sequences; Mice; NF-kappa B; NIMA-Interacting Peptidylprolyl Isomerase; Peptidylprolyl Isomerase; Phosphorylation; Promoter Regions, Genetic; RNA, Messenger; Signal Transduction; Tetracycline; Transcription Factor RelA

While Newcastle disease virus (NDV) causes serious infections in birds, it is apparently nonpathogenic in mammalian species, including humans. Previous observations and small-scale clinical trials indicated that NDV exerts oncolytic effects. Isolates of NDV were found to have selective affinity to transformed cells. We previously showed that the attenuated NDV strain MTH-68/H causes apoptotic cell death in cultures of PC12 rat pheochromocytoma cells. The aim of the present study was to extend MTH-68/H cytotoxicity testing with human tumor cell lines and to analyze certain biochemical aspects of its oncolytic effect. MTH-68/H was found to be able to kill a wide range of transformed cells by apoptosis. While caspase-8 and caspase-9 are not involved in MTH-68/H-induced apoptosis, activation of caspase-3 and caspase-12 was detected in virus-infected PC12 cells. A human glioblastoma cell line with repressible expression of the p53 protein did not show any difference in MTH-68/H sensitivity in its p53-expressing and p53-depleted states, indicating that the apoptotic process induced by MTH-68/H does not depend on p53. Apoptosis was accompanied by virus replication in two tumor cell lines tested (PC12 cells and HeLa human cervical cells), and signs of endoplasmic reticulum stress (phosphorylation of protein kinase R-like endoplasmic reticulum kinase and eIF2alpha) were also detected in transformed cells. In contrast, proliferation of nontransformed mouse and rat fibroblast cell lines and human primary fibroblasts was not affected by MTH-68/H treatment. MTH-68/H thus selectively kills tumor cell cultures by inducing endoplasmic reticulum stress leading to p53-independent apoptotic cell death.

Topics: Animals; Anti-Bacterial Agents; Apoptosis; Carcinoma; Caspase 12; Caspase 3; Cell Line, Transformed; Cell Line, Tumor; Cell Proliferation; Cell Transformation, Viral; Endoplasmic Reticulum; Enzyme Activation; Female; Glioblastoma; HCT116 Cells; HeLa Cells; HT29 Cells; Humans; Newcastle disease virus; Oxidative Stress; Pancreatic Neoplasms; PC12 Cells; Rats; Tetracycline; Tumor Suppressor Protein p53; Virus Replication

We have expressed the tumor suppressor p16 under the control of a tetracycline-sensitive promoter in two human glioblastoma cell lines which do not contain endogenous p16. Ectopic p16 expression led to a stable but reversible G1 phase cell cycle arrest, reduced the growth of both cell lines in cell culture, and almost abolished their in vitro tumorigenicity. U-87MG-tTA-p16 glioblastoma cells consistently formed tumors after subcutaneous injection into the flanks of nude mice. p16 expression in these tumors was strictly dependent on the presence or absence of tetracycline in the drinking water. Ectopic p16 reduced the tumor take rate (in vivo tumorigenicity) of U-87MG-tTA-p16 cells from 18/20 (90%) to 5 tumors/12 (42%) tumor cell injections. p16 positive and negative tumors differed with respect to their Ki67 labeling indices (34 +/- 4% vs. 52 +/- 6% , P < 0.001, student's t-test). These data are consistent with an in vitro and in vivo glioma suppressor role for p16. Interestingly, we observed a secondary reduction of pRB expression in tumors (and cell cultures) exposed to p16 for > or = 10 (6) days. pRB is p16's major downstream target. Hence, this finding might explain, why p16 expression neither significantly affected the morphology nor led to a reduction of size or growth rate of the tumors. Loss of pRB following p16 expression might severely limit the potential benefit of p16 gene therapy for glioblastoma.

Topics: Animals; Cell Cycle; Cell Division; Fungal Proteins; Genes, p16; Glioblastoma; Humans; Mice; Mice, Nude; Neoplasm Transplantation; Serine Endopeptidases; Tetracycline; Transfection; Tumor Cells, Cultured

Tetracycline controlled gene expression systems have become powerful tools in the analysis of gene function in mammalian cell culture as well as transgenic animals and plants. The original description of a tetracycline-regulated gene expression system is based on two plasmids, one of which constitutively expresses a tetracycline-controlled transactivator protein (tTA), a fusion protein between the tetracycline repressor of E. coli and the transcriptional activation domain of the VP16 protein of herpes simplex virus. The second plasmid contains the gene to be regulated by tTA under the control of an inducible promoter which consists of seven copies of the tetracycline resistance operator (tetO). Since this original description, many modifications have been described. In this report, we evaluate an autoregulatory tetracycline controlled system, in which the tTA is itself under the control of the tetO. We demonstrate that this autoregulatory tetracycline system produces adverse effects including cellular morphologic changes, growth rate attenuation and alterations in cell cycle distribution.

Topics: Animals; Cricetinae; Gene Expression Regulation; Glioblastoma; Growth Inhibitors; Homeostasis; Plasmids; Tetracycline; Tetracycline Resistance; Trans-Activators; Transfection; Tumor Cells, Cultured

Topics: Adenocarcinoma; Animals; Carcinoma, Bronchogenic; Carcinoma, Hepatocellular; Gallium; Glioblastoma; Hodgkin Disease; Humans; L-Lactate Dehydrogenase; Liver Neoplasms; Lung Neoplasms; Mediastinal Neoplasms; Methane; Mice; Muscular Diseases; Neoplasm Metastasis; Neoplasm Transplantation; Neoplasms, Experimental; Nitrosourea Compounds; Osteosarcoma; Rabbits; Radioisotopes; Radionuclide Imaging; Rats; Sarcoma; Sarcoma, Experimental; Technetium; Tetracycline; Transplantation, Homologous