title: The recombinant beta subunit of C-phycocyanin inhibits cell proliferation and induces apoptosis.
abstract: 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.
authors.affiliation: Department of Biology, Georgia Cancer Center, Georgia State University, University Plaza, Atlanta, GA 30303, USA.
authors.forename: Haizhen
authors.initials: H
authors.lastname: Wang
authors.forename: Yongding
authors.initials: Y
authors.lastname: Liu
authors.forename: Xueliang
authors.initials: X
authors.lastname: Gao
authors.forename: Christie L
authors.initials: CL
authors.lastname: Carter
authors.forename: Zhi-Ren
authors.initials: ZR
authors.lastname: Liu
mesh_terms: D000970:Antineoplastic Agents; D017209:Apoptosis / Q000187:drug effects; D020169:Caspases / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D006801:Humans; D008870:Microtubules / Q000378:metabolism; D010798:Phycocyanin / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology / Q000627:therapeutic use*; D021122:Protein Subunits / Q000235:genetics / Q000627:therapeutic use; D011994:Recombinant Proteins / Q000627:therapeutic use; D014404:Tubulin
chemical_list: D000970:Antineoplastic Agents; D021122:Protein Subunits; D011994:Recombinant Proteins; D014404:Tubulin; D010798:Phycocyanin; D020169:Caspases