Phycocyanin is a pigment-protein complex produced by certain cyanobacteria. It is composed of two protein subunits α-phycocyanin (18.4 kDa) and β-phycocyanin (21.3 kDa). As its name suggests phycocyanin in solution produces a blue-green colour (figure 1). Stable isolation of phycocyanin from Spirulina platensis has been achieved with a high pressure extraction process .
|Figure 1: Phycocyanin pigment extracted from Microcystis aeruginosa. The pigments light blue colour is evident. Credit: CyanoLakes. No changes were made. Creative Commons Attribution-Share Alike 4.0 International (CC-BY-SA-4.0).|
Using phycocyanin extracted from this source a recent study demonstrated that it induced cell death in pancreatic cancer cell lines through a mechanism involving autophagy . Interestingly on a panel of non-tumour cell lines phycocyanin had little effect. When beclin-1 was ablated by siRNA, which normally blocks autophagy, cell viability was rescued in phycocyanin treated pancreatic cancer cells .
In other models phycocyanin raised reactive oxygen species levels associated with apoptosis . KRAS mutant cancers such as pancreatic are known to be sensitive to redox shifts so it is of interest as to whether phycocyanin has a direct effect on the redox balance of pancreatic cancer cells.
- Seo YC, Choi WS, Park JH, Park JO, Jung KH, Lee HY. Stable isolation of phycocyanin from Spirulina platensis associated with high-pressure extraction process. Int J Mol Sci. 2013 Jan 16;14(1):1778-87. doi: 10.3390/ijms14011778. PubMed PMID: 23325046.
- Liao G, Gao B, Gao Y, Yang X, Cheng X, Ou Y. Phycocyanin Inhibits Tumorigenic Potential of Pancreatic Cancer Cells: Role of Apoptosis and Autophagy. Sci Rep. 2016 Oct 3;6:34564. doi: 10.1038/srep34564. PubMed PMID: 27694919.
- Pardhasaradhi BV, Ali AM, Kumari AL, Reddanna P, Khar A. Phycocyanin-mediated apoptosis in AK-5 tumor cells involves down-regulation of Bcl-2 and generation of ROS. Mol Cancer Ther. 2003 Nov;2(11):1165-70. PubMed PMID: 14617790.