title: DLC2/StarD13 plays a role of a tumor suppressor in astrocytoma.
abstract: Astrocytomas are tumors occurring in young adulthood. Astrocytic tumors             can be classified into four grades according to histologic features: grades I,             II, III and grade IV. Malignant tumors, those of grades III and IV, are characterized             by uncontrolled proliferation, which is known to be regulated by the family of             Rho GTPases. StarD13, a GAP for Rho GTPases, has been described as a tumor suppressor             in hepatocellular carcinoma. In the present study, IHC analysis on grades I-IV             brain tissues from patients showed StarD13 to be overexpressed in grades III and             IV astrocytoma tumors when compared to grades I and II. However, when we mined             the REMBRANDT data, we found that the mRNA levels of StarD13 are indeed higher             in the higher grades but much lower than the normal tissues. Knocking down StarD13             using siRNA led to a decrease in cell death and an increase in cell viability,             proving that StarD13 is indeed a tumor suppressor in astrocytomas. This was found             to be mainly through cell cycle arrest independently of apoptosis. Finally, we             detected an increase in p-ERK in StarD13 knockdown cells, uncovering a potential             link between Rho GTPases and ERK activation.
authors.affiliation: Department of Natural Sciences, The Lebanese American University,                     Beirut 1102 2801, Lebanon.
authors.forename: Sally
authors.initials: S
authors.lastname: El-Sitt
authors.forename: Bassem D
authors.initials: BD
authors.lastname: Khalil
authors.forename: Samer
authors.initials: S
authors.lastname: Hanna
authors.forename: Marwan
authors.initials: M
authors.lastname: El-Sabban
authors.forename: Najla
authors.initials: N
authors.lastname: Fakhreddine
authors.forename: Mirvat
authors.initials: M
authors.lastname: El-Sibai
mesh_terms: D001254:Astrocytoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D001932:Brain Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D048708:Cell Growth Processes / Q000235:genetics; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000235:genetics; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D020690:GTPase-Activating Proteins; D055785:Gene Knockdown Techniques; D016147:Genes, Tumor Suppressor; D005909:Glioblastoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D006801:Humans; D060787:Neoplasm Grading; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000008:administration & dosage / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D014162:Transfection; D025521:Tumor Suppressor Proteins / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism; D020830:rac1 GTP-Binding Protein / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
chemical_list: D020690:GTPase-Activating Proteins; C107953:RAC1 protein, human; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C473607:STARD13 protein, human; D025521:Tumor Suppressor Proteins; D048049:Extracellular Signal-Regulated MAP Kinases; D020764:cdc42 GTP-Binding Protein; D020830:rac1 GTP-Binding Protein; D020742:rhoA GTP-Binding Protein