The recombinant beta subunit of C-phycocyanin inhibits cell proliferation and induces apoptosis

Cancer Lett. 2007 Mar 8;247(1):150-8. doi: 10.1016/j.canlet.2006.04.002. Epub 2006 Jun 5.


C-Phycocyanin (C-PC) from blue-green algae has been reported to have various pharmacological characteristics, including anti-inflammatory and anti-tumor activities. In this study, we expressed the beta-subunit of C-PC (ref to as C-PC/beta) in Escherichia coli. We found that the recombinant C-PC/beta has anti-cancer properties. Under the treatment of 5 microM of the recombinant C-PC/beta, four different cancer cell lines accrued high proliferation inhibition and apoptotic induction. Substantially, a lower response occurred in non-cancer cells. We investigated the mechanism by which C-PC/beta inhibits cancer cell proliferation and induces apoptosis. We found that the C-PC/beta interacts with membrane-associated beta-tubulin and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Under the treatment of the C-PC/beta, depolymerization of microtubules and actin-filaments were observed. The cells underwent apoptosis with an increase in caspase-3, and caspase-8 activities. The cell cycle was arrested at the G0/G1 phase under the treatment of C-PC/beta. In addition, the nuclear level of GAPDH decreased significantly. Decrease in the nuclear level of GAPDH prevents the cell cycle from entering into the S phase. Inhibition of cancer cell proliferation and induction of apoptosis may potentate the C-PC/beta as a promising cancer prevention or therapy agent.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents
  • Apoptosis / drug effects
  • Caspases / metabolism
  • Cell Cycle / drug effects
  • Cell Line, Tumor
  • Cell Membrane / metabolism
  • Cell Proliferation / drug effects
  • Humans
  • Microtubules / metabolism
  • Phycocyanin / chemistry
  • Phycocyanin / genetics
  • Phycocyanin / pharmacology
  • Phycocyanin / therapeutic use*
  • Protein Subunits / genetics
  • Protein Subunits / therapeutic use
  • Recombinant Proteins / therapeutic use
  • Tubulin


  • Antineoplastic Agents
  • Protein Subunits
  • Recombinant Proteins
  • Tubulin
  • Phycocyanin
  • Caspases