uPAR and cathepsin B inhibition enhanced radiation-induced apoptosis in gliomainitiating cells
| Autor: | Christopher S. Gondi, Kiranmai Alapati, Rama Rao Malla, Bharathi Gorantla, Sreelatha Gopinath, Jasti S. Rao |
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| Rok vydání: | 2012 |
| Předmět: |
Cancer Research
Transcription Genetic Survivin Blotting Western Cathepsin D Down-Regulation Fluorescent Antibody Technique Mice Nude Apoptosis Biology Real-Time Polymerase Chain Reaction Cathepsin B Inhibitor of Apoptosis Proteins Receptors Urokinase Plasminogen Activator Immunoenzyme Techniques Mice Glioma Cell Line Tumor medicine In Situ Nick-End Labeling Animals Humans Immunoprecipitation RNA Messenger RNA Small Interfering neoplasms Reverse Transcriptase Polymerase Chain Reaction Cell Cycle Cell cycle medicine.disease Molecular biology biological factors Urokinase receptor Oncology Cell culture Basic and Translational Investigations Cancer research Neoplastic Stem Cells Neurology (clinical) biological phenomena cell phenomena and immunity |
| Zdroj: | Neuro-oncology. 14(6) |
| ISSN: | 1523-5866 |
| Popis: | Glioblastomas present as diffuse tumors with invasion into normal brain tissue and frequently recur or progress after radiation as focal masses because of glioma-initiating cells. The role of the urokinase-type plasminogen activator receptor (uPAR) and cathepsin B in stem-like phenotype has been extensively studied in several solid tumors. In the present study, we demonstrated that selection of glioma-initiating cells using CD133 expression leads to a specific enrichment of CD133(+) cells in both U87 and 4910 cells. In addition, CD133(+) cells exhibited a considerable amount of other stem cell markers, such as Nestin and Sox-2. Radiation treatment significantly enhanced uPAR and cathepsin B levels in glioma-initiating cells. To downregulate radiation-induced uPAR and cathepsin B expression, we used a bicistronic shRNA construct that simultaneously targets both uPAR and cathepsin B (pCU). Downregulation of uPAR and cathepsin B using pCU decreased radiation-enhanced uPAR and cathepsin B levels and caused DNA damage-induced apoptosis in glioma cell lines and glioma-initiating cells. The most striking finding of this study is that knockdown of uPAR and cathepsin B inhibited ongoing transcription by suppressing BrUTP incorporation at γH2AX foci. In addition, uPAR and cathepsin B gene silencing inversely regulated survivin and H2AX expression in both glioma cells and glioma-initiating cells. Pretreatment with pCU reduced radiation-enhanced expression of uPAR, cathepsin B, and survivin and enhanced DNA damage in pre-established glioma in nude mice. Taken together, our in vitro and in vivo findings suggest that uPAR and cathepsin B inhibition might serve as an adjunct to radiation therapy to target glioma-initiating cells and, therefore, for the treatment of glioma. |
| Databáze: | OpenAIRE |
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