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C-Phycocyanin, a selective cyclooxygenase-2 inhibitor, induces apoptosis in lipopolysaccharide-stimulated RAW 264.7 macrophages

Reddy, Madhava C and Subhashin, J and Mahipal, SVK and Bhat, Vadiraja B and Reddy, Srinivas P and Kiranmai, G and Madyastha, KM and Reddanna, P (2003) C-Phycocyanin, a selective cyclooxygenase-2 inhibitor, induces apoptosis in lipopolysaccharide-stimulated RAW 264.7 macrophages. In: Biochemical and Biophysical Research Communications, 304 (2). pp. 385-392.

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Abstract

C-Phycocyanin (C-PC) is one of the major biliproteins of Spirulina platensis, a blue green algae, with antioxidant and radical scavenging properties. It is also known to exhibit anti-in.ammatory and anti-cancer properties. However, the mechanism of action of C-PC is not clearly understood. Previously, we have shown that C-PC selectively inhibits cyclooxygenase-2 (COX-2), an inducible isoform that is upregulated during in.ammation and cancer. In view of the reported induction of apoptosis in cancer cells by cyclooxygenase-2 inhibitors, the present study is undertaken to test the e.ect of C-PC on LPS stimulated RAW 264.7 mouse macrophage cell line. These studies have shown a dose dependent reduction in the growth and multiplication of macrophage cell line by C-PC. This decrease in cell number appears to be mediated by C-PC induced apoptosis as evidenced by .ow cytometric and confocal microscopic studies. Cells treated with 20 lM C-PC showed typical nuclear condensation and 16.6% of cells in sub-Go=G1b phase. These cells also showed DNA fragmentation in a dose dependent manner. The studies on poly(ADP ribose) polymerase (PARP) cleavage showed typical fragmentation attern in C-PC treated cells. This C-PC induced apoptosis in RAW 264.7 cells appears to be mediated by the release of cytochrome c from mitochondria and independent of Bcl-2 expression. These e.ects of CPC on RAW 264.7 cells may be due to reduced PGE2 levels as a result of COX-2 inhibition.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to Elsevier Science
Keywords: C-Phycocyanin;Cyclooxygenase-2;Apoptosis;RAW 264.7 cells; Cytochrome c
Department/Centre: Division of Chemical Sciences > Organic Chemistry
Date Deposited: 11 Dec 2008 12:37
Last Modified: 19 Sep 2010 04:53
URI: http://eprints.iisc.ernet.in/id/eprint/16715

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