ABSTRACT
Because survivin is selectively expressed in and associated with an unfavorable prognosis in transitional cell carcinoma of the bladder (TCC), we treated T-24 cells with survivin siRNA. Survivin siRNA treatment caused a profound decrease of survivin protein that was associated with decreased cell growth, a specific G2/M arrest and increased cytochrome c release. Microarray analysis of apoptosis genes showed that levels of 14/114 gene products were decreased after 72 hours treatment with survivin siRNA, including survivin, three TNF receptors, Akt, c-Abl, caspases and their related genes and Bcl-2 and NF-kappaB signaling related genes. TNFR1, pro-caspase-2 and Akt protein levels were decreased after survivin siRNA treatment for 48 and 72 hours. Downregulation of survivin causes changes in mitosis and apoptosis, which may be related to changes in TNF receptors and NF-kappaB signaling.
Subject(s)
Microtubule-Associated Proteins/genetics , NF-kappa B/physiology , Neoplasm Proteins/genetics , Receptors, Tumor Necrosis Factor, Type I/genetics , Signal Transduction , Urinary Bladder Neoplasms/metabolism , Apoptosis , Caffeic Acids/pharmacology , Cell Line, Tumor , Chromones/pharmacology , Humans , Inhibitor of Apoptosis Proteins , Microtubule-Associated Proteins/metabolism , Morpholines/pharmacology , Neoplasm Proteins/metabolism , Phenylethyl Alcohol/analogs & derivatives , Phenylethyl Alcohol/pharmacology , Phosphorylation , Proto-Oncogene Proteins c-akt/metabolism , RNA, Messenger/analysis , RNA, Small Interfering/genetics , Receptors, Tumor Necrosis Factor, Type I/analysis , Survivin , Transfection , Urinary Bladder Neoplasms/geneticsABSTRACT
Myelin-associated inhibitors limit axonal regeneration in the injured brain and spinal cord. A common target of many neurite outgrowth inhibitors is the Rho family of small GTPases. Activation of Rho and a downstream effector of Rho, p160ROCK, inhibits neurite outgrowth. Here, we demonstrate that Rho is directly activated by the myelin-associated inhibitor Nogo-66. Using a binding assay to measure Rho activity, we detected increased levels of GTP Rho in PC12 and dorsal root ganglion (DRG) cell lysates after Nogo-66 stimulation. Rho activity levels were not affected by Amino-Nogo stimulation. Rho inactivation with C3 transferase promotes neurite outgrowth of chick DRG neurons in vitro, but with the delivery method used here, it fails to promote neurite outgrowth after corticospinal tract (CST) lesions in the adult rat. Inhibition of p160ROCK with Y-27632 also promotes neurite outgrowth on myelin-associated inhibitors in vitro. Furthermore, Y-27632 enhances sprouting of CST fibers in vivo and accelerates locomotor recovery after CST lesions in adult rats.
