ABSTRACT
To explore how cytohesin-1 (CYTH-1) small interfering RNA (siRNA) influences the insulin-like growth factor receptor (IGFR)-associated signal transduction in prostate cancer, we transfected human prostate cancer PC-3 cell lines with liposome-encapsulatedCYTH-1 siRNA in serum-free medium and exposed the cells to 100 nM IGF-1. The mRNA and protein levels of the signal molecules involved in the IGFR signaling pathways were determined by real-time PCR and detected by Western blotting. The relative mRNA levels of CYTH-1, c-Myc, cyclinD1 and IGF-1R (CYTH-1 siRNA group vs scrambled siRNA group) were 0.26 vs 0.97, 0.34 vs 1.06, 0.10 vs 0.95, and 0.27 vs 0.41 (P < 0.05 for all), respectively. The relative protein levels of CYTH-1, pIGF-1R, pIRS1, pAkt1, pErk1, c-Myc, and cyclinD1 (CYTH-1 siRNA group vsscrambled siRNA group) were 0.10 vs 1.00 (30 min), 0.10 vs 0.98 (30 min), 0.04 vs 0.50 (30 min), 0.10 vs 1.00 (30 min), 0.10 vs 1.00 (30 min), 0.13 vs 0.85 (5 h), and 0.08 vs 0.80 (7 h), respectively. The tyrosine kinase activity of IGF-1R was associated with CYTH-1. The proliferative activity of PC-3 cells transfected with CYTH-1 siRNA was significantly lower than that of cells transfected with scrambled siRNA at 48 h (40.5 vs87.6 percent, P < 0.05) and at 72 h (34.5 vs 93.5 percent, P < 0.05). In conclusion, the interference of siRNA with cytohesin-1 leads to reduced IGFR signaling in prostate cancer; therefore, CYTH-1 might serve as a new molecular target for the treatment of prostate cancer.
Subject(s)
Humans , Male , Guanine Nucleotide Exchange Factors/antagonists & inhibitors , Prostatic Neoplasms/metabolism , RNA, Small Interfering/pharmacology , Receptors, Somatomedin/metabolism , Signal Transduction/drug effects , Cell Line, Tumor , Cell Proliferation , Gene Expression Regulation, Neoplastic , GTPase-Activating Proteins/genetics , GTPase-Activating Proteins/metabolism , Guanine Nucleotide Exchange Factors/genetics , Insulin-Like Growth Factor I/metabolism , Phosphorylation , Prostatic Neoplasms/pathology , Real-Time Polymerase Chain Reaction , Receptors, Cytoplasmic and Nuclear/genetics , Receptors, Cytoplasmic and Nuclear/metabolismABSTRACT
Objective To observe the pathological changes of hippocampus and myelin in rats with frontal cereberal ischemia and reperfusion after treated with methylcobalamine and to discuss the mechanism of the cerebral protective effect of methylcobalamine.Methods Cerebral ischemia and reperfusion models were made by clamping bilateral carotid arteries.Forty-five male Wistar rats were randomly allocated to sham-operation group,ischemia-reperfusion group and methylcobalamine group(n=15).1,2,4 weeks after reperfusion the rats in each group were divided into three groups(n=5).The pathological changes of hippocampus and myelin were observed by using light microscope,HE staining,LFB staining and electron microscope.Results The pyramidal neurons in hippocampus in ischemia and reperfusion groups expressed putrescence and myelin necrosis or demyelination at 1st week,and the histomorphological changes at 4th week were significant than that at 2nd week.The followings were observed in electron microscope: dimness,partly solubilization and collapsablity in myelin.The pyramidal neurons in hippocampus of therapy groups were similar to normal one and myelin expressed compaction and shipshape.The changes were more obvious at 4th week.Conclusion Methylcobalamine can obviously decrease the ischemia lesion of hippocampus and myelin and protect the brain function.