Phosphatidylinositol 3-kinase and NF-kappaB regulate motility of invasive MDA-MB-231 human breast cancer cells by the secretion of urokinase-type plasminogen activator.
Cell migration is a fundamental aspect of the neoplastic cell metastasis. Here, we show that phosphatidylinositol (PI) 3-kinase is constitutively active and controls cell motility of highly invasive breast cancer cells by the activation of transcription factor, NF-kappaB. The urokinase-type plasminogen activator (uPA) promoter contains an NF-kappaB binding site, and uPA expression in MDA-MB-231 cells is induced by the constitutively active NF-kappaB. Thus, motility was inhibited by overexpression of a dominant negative p85alpha regulatory subunit of PI 3-kinase (p85DN), as well as by pretreatment of cells with specific inhibitors of the p110 catalytic subunit of PI 3-kinase, wortmannin and LY294002. The involvement of gene transcription in cell motility was suggested because treatment with actinomycin D and cycloheximide, which inhibit transcription and new protein synthesis, respectively, abolished endogenous migration of MDA-MB-231 cells. Although wortmannin, Ly294002, or overexpression of p85DN did not significantly reduce DNA binding activity of NF-kappaB in nuclear extracts, wortmannin, Ly294002, and the overexpression of p85DN or IkappaBalpha inhibited constitutive activation of NF-kappaB in a reporter gene assay. Highly invasive MDA-MB-231 cells constitutively secreted uPA in amounts significantly higher than poorly invasive MCF-7 cells. Furthermore, inhibition of NF-kappaB markedly attenuated endogenous migration, and inhibition of PI 3-kinase and NF-kappaB reduced secretion of uPA. Our data suggest a link between constitutively active PI 3-kinase, NF-kappaB, and secretion of uPA, which is responsible for the migration of highly invasive breast cancer cells. Thus, constitutively active PI 3-kinase controls cell motility by the regulation of expression of uPA through the activation of NF-kappaB.
Sliva
Daniel
D
Cancer Research Laboratory, the Signal Transduction Laboratory, and the Experimental Cell Research Program, Methodist Research Institute, Clarian Health Partners Inc., Indianapolis, Indiana 46202, USA. dsliva@clarian.org
Rizzo
Maria T
MT
English
Denis
D
D000730:Androstadienes / Q000494:pharmacology; D001943:Breast Neoplasms / Q000473:pathology* / Q000503:physiopathology*; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology*; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics; D002867:Chromones / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D017930:Genes, Reporter; D006801:Humans; D020672:I-kappa B Proteins; D009025:Morpholines / Q000494:pharmacology; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism*; D009361:Neoplasm Invasiveness; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D010957:Plasmids; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014162:Transfection; D014407:Tumor Cells, Cultured; D014568:Urokinase-Type Plasminogen Activator / Q000378:metabolism*; D000077191:Wortmannin; D001616:beta-Galactosidase / Q000235:genetics
D000730:Androstadienes; D002867:Chromones; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D020672:I-kappa B Proteins; D009025:Morpholines; D016328:NF-kappa B; C000606204:NFKBIA protein, human; D011993:Recombinant Fusion Proteins; D000072000:NF-KappaB Inhibitor alpha; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D015500:Chloramphenicol O-Acetyltransferase; D019869:Phosphatidylinositol 3-Kinases; D001616:beta-Galactosidase; D014568:Urokinase-Type Plasminogen Activator; D000077191:Wortmannin