RNAi-mediated Human Nestin Silence Inhibits Proliferation and Migration of Malignant Melanoma Cells by G1/S Arrest via Akt-GSK3β-Rb Pathway / 华中科技大学学报（医学）（英德文版）

Human Nestin (hNestin) has been found to express in melanoma,and its expression is positively correlated with the advanced stage of melanoma.However,the precise role of hNestin in the development of melanoma has not been fully understood.The present study aimed to explore the role of hNestin in the proliferation and invasion of melanoma cells.The lentivirus vector carrying a short hairpin RNAs (shRNAs) targeting hNestin (hNestin-shRNA-LV) was stably infected into human melanoma cells UACC903,which expressed high levels of hNestin.The effects of hNestin knockdown on the proliferation,apoptosis,migration of melanoma cells and the related signaling pathways were investigated by immunofluorence,Western blotting and reverse transcription polymerase chain reaction (RT-PCR),respectively.The results showed that hNestin was expressed in most melanoma specimens and the melanoma cells studied.Knockdown of hNestin expression significantly inhibited the proliferation of melanoma cells,blocked the formation of cell colony,arrested cell cycle at G1/S stage and suppressed the activation of Akt and GSK3β.hNestin-silent cells also showed a sheet-like appearance with tight cell-cell adhesion,decreased membrane expression of N-cadherin and β-catenin,and attenuated migration.Furthermore,hNestin silence resulted in the inhibition of tumor growth in vivo.Our study indicates that hNestin knockdown suppresses the proliferation of melanoma cells,which might be through affecting Akt-GSK3β-Rb pathway-mediated G1/S arrest,and hNestin silence inhibits the migration by selectively modulating the expression of cell adhesion molecules in the process of epithelial-mesenchymal transition.

Relationship between α-actinin and cardiac function in rats with myocardial ischemia-reperfusion / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the relationship between α-actinin content and cardiac function in rats during myocardial ischemia-reperfusion.</p><p><b>METHODS</b>Thirty-two rats were randomized equally into sham-operated group, 30 min ischemia group, 1 h ischemia group, and 1 h ischemia with 2 h reperfusion group. Acute myocardial ischemia was induced in the 3 ischemia groups by ligation of the left anterior descending coronary artery, and the cardiac functions were evaluated. The myocardial contents of α-actinin was measured by immunohistochemistry, and phospholipase C (PLC) and phosphatidylinositol-3-kinase (PI3K) contents were determined by ELISA after the operations.</p><p><b>RESULTS</b>The left ventricular systolic pressure (LVSP), +dp/dt max, and -dp/dt max tended to decrease during myocardial ischemia, and increased after reperfusion, and the left ventricular end-diastolic pressure (LVEDP) showed reverse changes. The levels of α-actinin decreased with prolonged ischemia, showing a significant difference in 1 h ischemia group from those in the other 3 groups. PI3K and PLC contents were significantly increased with prolonged myocardial ischemia. Stimulation by LY-294002 and U-73122 caused enhanced contraction of single cardiomyocytes, and also increased the fluorescence intensity of α-actinin in the cardiomyocytes compared with that in 1 h ischemia group.</p><p><b>CONCLUSIONS</b>The cardiac dysfunction during acute ischemia-reperfusion in rats may be related with the changes of myocardial α-actinin content, which are probably a result of increased PI3K and PLC contents in the ischemic myocardium.</p>

Role of Na(+)-K(+)-ATPase in lipopolysaccharide-induced cardiomyocyte hypertrophy in rats / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the possible mechanism of lipopolysaccharide (LPS)-induced cardiomyocyte hypertrophy in rats.</p><p><b>METHODS</b>Neonatal rat cardiomyocytes cultured in vitro were stimulated with 100 µg/L LPS for 1, 4 or 8 h and scanned by atomic force microscopy (AFM) for measurement of the two-dimensional area, three-dimensional surface area and volume of each cell. The total proteins and Na(+)-K(+)-ATPase activity in the cardiomyocytes were determined. The same measurements were also carried out in neonatal rat cardiomyocyte cultures stimulated by 0.5 µmol/L ouabain for 8 h and the total protein levels were measured.</p><p><b>RESULTS</b>Following a 8-hour stimulation with LPS, the two-dimensional area, three-dimensional surface area and volume of the single cardiomyocyte became enlarged and the total cellular proteins increased significantly as compared with those in the normal control cells (P < 0.05). LPS treatment for 4 and 8 h resulted in significantly decreased activity of Na(+)-K(+)-ATPase in the cardiomyocytes (P < 0.05). In the cells treated with ouabain for 8 h, the two-dimensional area, three-dimensional surface area, volume of the single cardiomyocyte and the total cellular proteins increased significantly in comparison with the normal control group (P < 0.05).</p><p><b>CONCLUSION</b>LPS can result in cardiomyocyte hypertrophy in rats possibly in relation to lowered Na(+)-K(+)-ATPase activity in the cardiomyocytes after LPS exposure.</p>