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

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 β-subunit of C-PC (ref to as C-PC/β) in Escherichia coli. We found that the recombinant C-PC/β has anti-cancer properties. Under the treatment of 5 μM of the recombinant C-PC/β, 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/β inhibits cancer cell proliferation and induces apoptosis. We found that the C-PC/β interacts with membrane-associated β-tubulin and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Under the treatment of the C-PC/β, 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/β. 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/β as a promising cancer prevention or therapy agent.