casein-kinase-ii and Retinal-Neovascularization

Ubiquitous protein kinase CK2 participates in a variety of key cellular functions. We have explored CK2 involvement in angiogenesis. As shown previously, CK2 inhibition reduced endothelial cell proliferation, survival and migration, tube formation, and secondary sprouting on Matrigel. Intraperitoneally administered CK2 inhibitors significantly reduced preretinal neovascularization in a mouse model of proliferative retinopathy. In this model, CK2 inhibitors had an additive effect with somatostatin analog, octreotide, resulting in marked dose reduction for the drug to achieve the same effect. CK2 inhibitors may thus emerge as potent future drugs aimed at inhibiting pathological angiogenesis. Immunostaining of the retina revealed predominant CK2 expression in astrocytes. In human diabetic retinas, mRNA levels of all CK2 subunits decreased, consistent with increased apoptosis. Importantly, a specific CK2 inhibitor prevented recruitment of bone marrow-derived hematopoietic stem cells to areas of retinal neovascularization. This may provide a novel mechanism of action of CK2 inhibitors on newly forming vessels.

Topics: Animals; Animals, Newborn; Casein Kinase II; Cattle; Cell Movement; Cells, Cultured; Disease Models, Animal; Drug Therapy, Combination; Endothelial Cells; Hematopoietic Stem Cell Transplantation; Hematopoietic Stem Cells; Humans; Mice; Mice, Inbred C57BL; Models, Biological; Octreotide; Protein Kinase Inhibitors; Retina; Retinal Neovascularization

We previously documented protein kinase CK2 involvement in retinal neovascularization. Here we describe retinal CK2 expression and combined effects of CK2 inhibitors with the somatostatin analog octreotide in a mouse model of oxygen-induced retinopathy (OIR). CK2 expression in human and rodent retinas with and without retinopathy and in astrocytic and endothelial cultures was examined by immunohistochemistry, Western blotting, and reverse transcriptase-polymerase chain reaction. A combination of CK2 inhibitors, emodin or 4,5,6,7-tetrabromobenzotriazole, with octreotide was injected intraperitoneally from postnatal (P) day P11 to P17 to block mouse OIR. All CK2 subunits (alpha, alpha', beta) were expressed in retina, and a novel CK2alpha splice variant was detected by reverse transcriptase-polymerase chain reaction. CK2 antibodies primarily reacted with retinal astrocytes, and staining was increased around new intraretinal vessels in mouse OIR and rat retinopathy of prematurity, whereas preretinal vessels were negative. Cultured astrocytes showed increased perinuclear CK2 staining compared to endothelial cells. In the OIR model, CK2 mRNA expression increased modestly on P13 but not on P17. Octreotide combined with emodin or 4,5,6,7-tetrabromobenzotriazole blocked mouse retinal neovascularization more efficiently than either compound alone. Based on its retinal localization, CK2 may be considered a new immunohistochemical astrocytic marker, and combination of CK2 inhibitors and octreotide may be a promising future treatment for proliferative retinopathies.

Topics: Angiogenesis Inhibitors; Animals; Astrocytes; Casein Kinase II; Drug Combinations; Emodin; Enzyme Inhibitors; Humans; Immunohistochemistry; Infant, Newborn; Mice; Molecular Sequence Data; Rats; Retina; Retinal Neovascularization; Retinopathy of Prematurity; Reverse Transcriptase Polymerase Chain Reaction; Somatostatin

The purpose of the study was to characterize signaling intermediates involved in angiogenic responses of retinal endothelial cells (RECs) to the extracellular matrix and growth factors, by using specific inhibitors.. Tubelike structure formation and the development of secondary sprouts on a basement membrane (BM) matrix, cell proliferation, and cell migration were studied in cultures of bovine and human RECs. Specific inhibitors were tested for inhibition of retinal neovascularization in a mouse model of oxygen-induced retinopathy (OIR).. In initial experiments, the broad-spectrum protein kinase inhibitors, H7 and H89, stabilized REC tubes on BM matrix and inhibited secondary sprouting, cell migration, and cell proliferation. Among more specific kinase inhibitors tested, only inhibitors of protein kinase CK2 (formerly, casein kinase II), such as emodin and DRB, were able to duplicate the effects of H7 and H89. Actinomycin D caused only minor changes in angiogenic assays, suggesting that CK2's effects on REC did not involve its known impact on transcription. The extent of retinal neovascularization in a mouse OIR model was reduced >70% (versus untreated or vehicle-treated groups) after treatment with emodin (6 days at 60 mg/kg per day) and by approximately 60% after treatment at the same dose with TBB, the most specific CK2 inhibitor known. In the treated retinas, the main vascular tree had minimal changes, but the neovascular tufts were greatly reduced in number or absent.. This is the first demonstration of the involvement of ubiquitous protein kinase CK2 in angiogenesis. Naturally derived CK2 inhibitors may be useful for treatment of proliferative retinopathies.

Topics: Animals; Basement Membrane; Casein Kinase II; Cattle; Cell Division; Cell Movement; Cells, Cultured; Enzyme Inhibitors; Humans; Mice; Mice, Inbred C57BL; Oxygen; Retinal Diseases; Retinal Neovascularization; Retinal Vessels