PJ-34 inhibits PARP-1 expression and ERK phosphorylation in glioma-conditioned brain microvascular endothelial cells.
Inhibitors of PARP-1(Poly(ADP-ribose) polymerase-1) act by competing with NAD(+), the enzyme physiological substrate, which play a protective role in many pathological conditions characterized by PARP-1 overactivation. It has been shown that PARP-1 also promotes tumor growth and progression through its DNA repair activity. Since angiogenesis is an essential requirement for these activities, we sought to determine whether PARP inhibition might affect rat brain microvascular endothelial cells (GP8.3) migration, stimulated by C6-glioma conditioned medium (CM). Through wound-healing experiments and MTT analysis, we demonstrated that PARP-1 inhibitor PJ-34 [N-(6-Oxo-5,6-dihydrophenanthridin-2-yl)-N,N-dimethylacetamide] abolishes the migratory response of GP8.3 cells and reduces their viability. PARP-1 also acts in a DNA independent way within the Extracellular-Regulated-Kinase (ERK) signaling cascade, which regulates cell proliferation and differentiation. By western analysis and confocal laser scanning microscopy (LSM), we analyzed the effects of PJ-34 on PARP-1 expression, phospho-ERK and phospho-Elk-1 activation. The effect of MEK (mitogen-activated-protein-kinase-kinase) inhibitor PD98059 (2-(2-Amino-3-methoxyphenyl)-4 H-1-benzopyran-4-one) on PARP-1 expression in unstimulated and in CM-stimulated GP8.3 cells was analyzed by RT-PCR. PARP-1 expression and phospho-ERK activation were significantly reduced by treatment of GP8.3 cells with PJ-34 or PD98059. By LSM, we further demonstrated that PARP-1 and phospho-ERK are coexpressed and share the same subcellular localization in GP8.3 cells, in the cytoplasm as well as in nucleoplasm. Based on these data, we propose that PARP-1 and phospho-ERK interact in the cytosol and then translocate to the nucleus, where they trigger a proliferative response. We also propose that PARP-1 inhibition blocks CM-induced endothelial migration by interfering with ERK signal-transduction pathway.
Department of Biomedical Sciences and Biotecnology, University of Catania, Via Santa Sofia 64, 95125 Catania, Italy.
Carla
C
Motta
Department of Biomedical Sciences and Biotecnology, University of Catania, Via Santa Sofia 64, 95125 Catania, Italy.
Floriana
F
D'Angeli
Department of Biomedical Sciences and Biotecnology, University of Catania, Via Santa Sofia 64, 95125 Catania, Italy.
Marina
M
Scalia
Department of Chemical Sciences, University of Catania, Viale Andrea Doria 6, 95125 Catania, Italy.
Cristina
C
Satriano
Department of Biomedical Sciences and Biotecnology, University of Catania, Via Santa Sofia 64, 95125 Catania, Italy.
Davide
D
Barbagallo
Department of Biomedical Sciences and Biotecnology, University of Catania, Via Santa Sofia 64, 95125 Catania, Italy.
Irina
I
Naletova
Department of Biomedical Sciences and Biotecnology, University of Catania, Via Santa Sofia 64, 95125 Catania, Italy.
Carmelina Daniela
CD
Anfuso
Department of Biomedical Sciences and Biotecnology, University of Catania, Via Santa Sofia 64, 95125 Catania, Italy.
Gabriella
G
Lupo
Department of Biomedical Sciences and Biotecnology, University of Catania, Via Santa Sofia 64, 95125 Catania, Italy. Electronic address: spinavit@unict.it.
Vittoria
V
Spina-Purrello
D021581:Active Transport, Cell Nucleus / Q000187:drug effects; D000818:Animals; D001921:Brain / Q000098:blood supply*; D001932:Brain Neoplasms / Q000378:metabolism*; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D017077:Culture Media, Conditioned / Q000378:metabolism*; D042783:Endothelial Cells / Q000187:drug effects* / Q000201:enzymology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D005910:Glioma / Q000378:metabolism*; D055806:Microvessels / Q000187:drug effects* / Q000201:enzymology; D019899:Paracrine Communication / Q000187:drug effects*; D010616:Phenanthrenes / Q000494:pharmacology*; D010766:Phosphorylation; D000071137:Poly (ADP-Ribose) Polymerase-1; D000067856:Poly(ADP-ribose) Polymerase Inhibitors / Q000494:pharmacology*; D011065:Poly(ADP-ribose) Polymerases / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects; D050807:ets-Domain Protein Elk-1 / Q000378:metabolism
D017077:Culture Media, Conditioned; C494113:Elk1 protein, mouse; C434926:N-(oxo-5,6-dihydrophenanthridin-2-yl)-N,N-dimethylacetamide hydrochloride; D010616:Phenanthrenes; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D047428:Protein Kinase Inhibitors; D050807:ets-Domain Protein Elk-1; C499321:Parp1 protein, mouse; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; D048049:Extracellular Signal-Regulated MAP Kinases
C6 glioma cells; GP8.3 cells; PARP-1; PD98059; PJ-34; phospho-ERK