ABSTRACT
Objectives: This study examines the impact of integrin-linked kinase (ILK), protein kinase B (AKT), glycogen synthase kinase-3ß (GSK-3ß), and ß-catenin signal molecules in SKOV-3 ovarian cancer cells adhered to fibronectin. Materials and Methods: Expression levels of α4, αv, ß1, and ß6 integrin subunits known as the fibronectin ligand were investigated with the flow cytometry technique. The effects of ILK, AKT, GSK-3ß, and ß-catenin on the binding of SKOV-3 cells to fibronectin were examined by using the Real-Time Cellular Analysis (RTCA) method. Additionally, the interaction of these proteins was investigated by using Western blot analysis. Results: The results show that the expression levels of integrin subunits were ranked as αv (67.8%), followed by α4 (48.55%), ß6 (32.05%), and ß1 (31%) on SKOV-3 cells. RTCA results showed that ILK (10 µM Cpd22), GSK-3ß (50 µM GSK-3ß inhibitor-XI), AKT (35 µM FPA 124), and ß-catenin (50 µM cardamonin) inhibitors decreased significantly (P<0.01) binding to fibronectin at 24 hr. Western studies in SKOV-3 cells adhered to fibronectin have shown that in inhibition of ILK, AKT expression was strongly inhibited, whereas, in the inhibition of AKT, ILK expression was strongly inhibited. Furthermore, the expression of ß-catenin is partially reduced in inhibition of these two molecules. In ß-catenin inhibition, AKT and ILK expressions are also strongly inhibited. Conclusion: ILK, AKT, GSK-3ß, and ß-catenin were found to be fundamental molecules in binding of SKOV-3 cells to fibronectin. ILK and AKT affect strongly the level of expression of each other, and both also affect the signal path of ß-catenin.
ABSTRACT
OBJECTIVES: To investigate the effects of intracellular calcium (Ca2+) mobilization, ß-catenin and Akt signal pathways after the binding of metastatic ovarian cells to fibronectin. MATERIALS AND METHODS: The expression levels of α4ß1 and αvß6 integrin were determined using α4, ß1, αv, and ß6 antibodies using flow cytometry on PEO-1 cells. The effect of [Ca2+]i on cell adhesion capacity was investigated using RTCA after stimulating PEO-1 cells using thapsigargin and tunicamycin. The binding rate of PEO-1 cells to fibronectin was also investigated in the presence of either different concentrations of cardamonin, which inhibits the accumulation of ß-catenin, or different concentrations of FPA 124, which is a specific inhibitor for the PKB/Akt signal pathway, using RTCA. RESULTS: RTCA analysis results showed that increasing [Ca2+]i through leakage of the calcium pool was strongly effective on PEO-1 cell binding to fibronectin. Extracellular calcium influx also reduced the binding of PEO-1 cells. Cell binding to fibronectin was also inhibited with a ratio of 64% in the presence of 100 µM cardamonin compared with untreated control cells. Finally, it was found that PKB/Akt inhibition with 15 µM FPA 124 decreased the binding of PEO-1 cells to fibronectin with a ratio of 88% compared with untreated control cells. CONCLUSION: PEO-1 cell binding to fibronectin via integrins could be related to intracellular Ca2+ mobilization and Akt signaling.
ABSTRACT
The ultrastructural changes on capillaries of the dermis in diabetic and benfluorex-vitamin C treated diabetic rats have been investigated. Three groups of 21 Wistar albino rats were used in the examination: control, diabetes, and benfluorex-vitamin C treated diabetic rats. Diabetes was induced by injection of streptozotocin. The streptozotocin-induced group was treated for 21 days with vitamin C and benfluorex, of which antidiabetic and antihyperlipidemic effects were experimentally proved. Samples taken from the skin of rats' legs were examined under transmission electron microscopy. Swollen endothelial cells, narrowed capillary lumens, a thickened basement membrane, and fusion of mitochondrial cristae in the capillaries of diabetic rat dermis were seen. In the benfluorex-vitamin C treated group, contrary to the diabetic group, neither signs of degeneration in endothelial cells nor a significant difference with the control group with regard to capillary structure were observed. Amelioration in capillaries appears to be due to benfluorex and vitamin C treatment in diabetes.
