Effect of CPEB4 on Migration and Cycle of Chronic Myeloid Leukemia Cell / 中国实验血液学杂志

OBJECTIVE@#To investigate the effects of CPEB4 on the migration and cycle of K562 cells and the changes of protein molecules that may be involved in the regulatory mechanism.@*METHODS@#Western blot was used to detect the expression of CPEB4 in normal leukocytes and K562 cells. The overexpression plasmid pcDNA3.1(+)-His-CPEB4, silencing plasmid pPLK+Puro-CPEB4 shRNA were transfected into K562 cells by electroporation so as to change CPEB4. The transfection efficiency was detected by Western blot. Finally, the migration and cycle of different cells were detected by Transwell chamber and flow cytometry.Western blot was used to detect the expression changes of MMP2, MMP9, CDK4, CyclinD1 and P21 proteins.@*RESULTS@#Compared with normal white blood cells, the expression of CPEB4 protein in K562 cells was significantly enhanced (P＜0.01); Compared with the control group, CPEB4-silenced K562 cells showed that the cell migration ability was significantly enhanced (P＜0.01); G/G phase cell ratio reduced, G/M phase cell ratio increased, and cell cycle progression accelerated（P＜0.01）, The expression levels of MMP2 (P＜0.05), MMP9 (P＜0.05), CDK4 (P＜0.01), CyclinD1 (P＜0.01) proteins increased significantly. The expression level of P21 protein significantly decreased (P＜0.01). The migration ability of K562 cells after CPEB4 overexpression was decreased (P＜0.01), the cell ratio of G/G phase in the cell cycle increased, the cell proportion of S phase decreased and the cell cycle progression was arrested at G/G phase (P＜0.01). The expression of P21 protein increased, MMP2 , MMP9, CDK4, CyclinD1 protein expression decreased significantly（P＜0.05-0.01）.@*CONCLUSION@#CPEB4 can inhibit the migration of K562 cells and arrest cell cycle progression at G/G phase. Its mechanism may be related with regulating the exprossion of MMP2, MMP9, CDK4, CyclinD1 and P21 proteins.

Effect of CPEB4 on Proliferation and Apoptosis of Chronic Myeloid Leukemia Cells / 中国实验血液学杂志

OBJECTIVE@#To explore the expression of CPEB4 in K562 cells, the biological activity and its possible molecular mechanisms.@*METHODS@#Western blot was used to detect the expression of CPEB4 in normal leukocytes and K562 cells. The overexpression plasmid pcDNA3.1(+)-His-CPEB4 and the silencing plasmid pPLK+Puro-CPEB4 shRNA were transfected into K562 cells to change the expression of CPEB4 in K562 cells, and the transfection efficiency was detected by Western blot. Finally, CCK-8 and flow cytometry were used to detect the proliferation and apoptosis of differently treated cells, and the expression changes of proliferation and apoptosis marker proteins (AKT, p-AKT, caspase-3, BCL-2) were detected by Western blot.@*RESULTS@#Compared with normal leukocytes, the expression of CPEB4 protein in K562 cells was higher (P＜0.01). Compared with the control group, the proliferation of CPEB4-silenced K562 cells significantly increased (P＜0.01), the number of apoptotic cell significantly decreased, and expression of AKT, p-AKT and BCL-2 was significantly increased, the protein expression of caspase-3 was significantly reduced. The proliferation of K562 cells after CPEB4 overexpression was slowed down (P＜0.05), the number of apoptotic cells significantly increased,the expressions of AKT, p-AKT and BCL-2 were significantly down-regulated, and the expression of caspase-3 was up-regulated.@*CONCLUSION@#CPEB4 can inhibit the proliferation and promote the apoptosis of K562 cells, the AKT, p-AKT, BCL-2 and caspase-3 are involved in the regulation mechanism.

N-methyl-D-aspartate receptors mediate diphosphorylation of extracellular signal-regulated kinases through Src family tyrosine kinases and Ca2+/calmodulin-dependent protein kinase II in rat hippocampus after cerebral ischemia / 神经科学通报·英文版

<p><b>OBJECTIVE</b>Extracellular signal-regulated kinases (ERKs) can be activated by calcium signals. In this study, we investigated whether calcium-dependent kinases were involved in ERKs cascade activation after global cerebral ischemia.</p><p><b>METHODS</b>Cerebral ischemia was induced by four-vessel occlusion, and the calcium-dependent proteins were detected by immunoblot.</p><p><b>RESULTS</b>Lethal-simulated ischemia significantly resulted in ERKs activation in N-methyl-D-aspartate (NMDA) receptor-dependent manner, accompanying with differential upregulation of Src kinase and Ca2+/calmodulin-dependent protein kinase II (CaMKII) activities. With the inhibition of Src family tyrosine kinases or CaMKII by administration of PP2 or KN62, the phosphorylation of ERKs was impaired dramatically during post-ischemia recovery. However, ischemic challenge also repressed ERKs activity when Src kinase was excessively activated.</p><p><b>CONCLUSION</b>Src family tyrosine kinases and CaMKII might be involved in the activation of ERKs mediated by NMDA receptor in response to acute ischemic stimuli in vivo, but the intense activation of Src kinase resulted from ischemia may play a reverse role in the ERKs cascade.</p>