Down-regulation of uPAR and cathepsin B retards cofilin dephosphorylation.
Cathepsin B and uPAR play key roles in cancer cell migration and invasion. Here, we demonstrate that the simultaneous, siRNA-mediated down-regulation of uPAR and cathepsin B inhibits glioma cell migration and is accompanied by cytoskeletal condensation. We show that the dephosphorylation of cofilin is inhibited by the down-regulation of uPAR alone and, to a lesser extent, by the down-regulation of cathepsin B alone, and that the effect was much higher with the down-regulation of both molecules by pUC. Using FACS analysis and western blotting for the alphaVbeta3 integrin heterodimer, we determined that down-regulating uPAR subsequently causes the down-regulation of the alphaVbeta3 integrin heterodimer. As evidenced by western blot analysis of ERK1/2, pERK1/2, p38MAPK, p-p38MAPK, AKT, pAKT and PI3-k, the MEK and PI3-k pathways are inhibited. From cytoskeleton studies, we observed that the down-regulation of uPAR caused cytoskeletal condensation and that the simultaneous down-regulation of uPAR and cathepsin B was even more effective at inducing cytoskeletal condensation than uPAR alone. Our results demonstrate the relevance of uPAR in cytoskeletal dynamics and the potential of uPAR and cathepsin B as targets in the treatment of malignant gliomas.
Gondi
Christopher S
CS
Program of Cancer Biology, Department of Biomedical and Therapeutic Sciences, University of Illinois College of Medicine at Peoria, Peoria, IL 61656, USA.
Kandhukuri
Neelima
N
Kondraganti
Shakuntala
S
Gujrati
Meena
M
Olivero
William C
WC
Dinh
Dzung H
DH
Rao
Jasti S
JS
D051339:Actin Depolymerizing Factors / Q000378:metabolism*; D000199:Actins / Q000378:metabolism; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D015153:Blotting, Western; D002401:Cathepsin B / Q000235:genetics* / Q000502:physiology; D045744:Cell Line, Tumor; D003599:Cytoskeleton / Q000378:metabolism; D015536:Down-Regulation; D006801:Humans; D039302:Integrin alphaVbeta3 / Q000378:metabolism; D008954:Models, Biological; D051058:Oncogene Protein v-akt / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation; D010957:Plasmids / Q000235:genetics; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D011956:Receptors, Cell Surface / Q000235:genetics* / Q000502:physiology; D055293:Receptors, Urokinase Plasminogen Activator; D014162:Transfection; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D051339:Actin Depolymerizing Factors; D000199:Actins; D051017:Apoptosis Regulatory Proteins; D039302:Integrin alphaVbeta3; C524898:PLAUR protein, human; D034741:RNA, Small Interfering; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; C101296:prostate apoptosis response-4 protein; D019869:Phosphatidylinositol 3-Kinases; D051058:Oncogene Protein v-akt; D048051:p38 Mitogen-Activated Protein Kinases; D002401:Cathepsin B