Alteration of mitochondrial membrane potential by Spirulina platensis C-phycocyanin induces apoptosis in the doxorubicin-resistant human hepatocellular-carcinoma cell line HepG2

• Published in: Biotechnology and applied biochemistry 2007-08, Vol.47 (3-4), p.159-167
• Main Authors: ROY, Karnati R, ARUNASREE, Kalle M, REDDY, Nishant P, DHEERAJ, Bhavanasi, GORLA VENKATESWARA REDDY, REDDANNA, Pallu
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Biotechnology; Cyanophyta; Fundamental and applied biological sciences. Psychology; Spirulina platensis
• ISSN: 0885-4513; 1470-8744
• DOI: 10.1042/BA20060206

C-PC (C-phycocyanin) is a water-soluble biliprotein from the filamentous cyanobacterium Spirulina platensis with potent antioxidant, anti-inflammatory and anticancerous properties. In the present study, the effect of C-PC was tested on the proliferation of doxo-rubicin-sensitive (S-HepG2) and -resistant (R-HepG2) HCC (hepatocellular carcinoma) cell lines. These studies indicate a 50% decrease in the proliferation of S- and R-HepG2 cells treated with 40 and 50 kM C-PC for 24 h respectively. C-PC also enhanced the sensitivity of R-HepG2 cells to doxorubicin. R-HepG2 cells treated with C-PC showed typical apoptotic features such as membrane blebbing and DNA fragmentation. Flow-cytometric analysis of R-HepG2 cells treated with 10, 25 and 50 kM C-PC for 24 h showed 18.8, 39.72 and 65.64% cells in sub-G sub(0)/G sub(1) -phase respectively. Cytochrome c release, decrease in membrane potential, caspase 3 activation and PARP [poly(ADP-ribose) polymerase] cleavage were observed in C-PC-treated R-HepG2 cells. These studies also showed down-regulation of the anti-apoptotic protein Bcl-2 and up-regulation of the pro-apoptotic Bax (Bcl2-associated X-protein) protein in the R-HepG2 cells treated with C-PC. The present study thus demonstrates that C-PC induces apoptosis in R-HepG2 cells and its potential as an anti-HCC agent.