title: Sensitivity of tumor cells towards CIGB-300 anticancer peptide relies on its nucleolar localization.
abstract: CIGB-300 is a novel anticancer peptide that impairs the casein kinase 2-mediated phosphorylation by direct binding to the conserved phosphoacceptor site on their substrates. Previous findings indicated that CIGB-300 inhibits tumor cell proliferation in vitro and induces tumor growth delay in vivo in cancer animal models. Interestingly, we had previously demonstrated that the putative oncogene B23/nucleophosmin (NPM) is the major intracellular target for CIGB-300 in a sensitive human lung cancer cell line. However, the ability of this peptide to target B23/NPM in cancer cells with differential CIGB-300 response phenotype remained to be determined. Interestingly, in this work, we evidenced that CIGB-300's antiproliferative activity on tumor cells strongly correlates with its nucleolar localization, the main subcellular localization of the previously identified B23/NPM target. Likewise, using CIGB-300 equipotent doses (concentration that inhibits 50% of proliferation), we demonstrated that this peptide interacts and inhibits B23/NPM phosphorylation in different cancer cell lines as evidenced by in vivo pull-down and metabolic labeling experiments. Moreover, such inhibition was followed by a fast apoptosis on CIGB-300-treated cells and also an impairment of cell cycle progression mainly after 5 h of treatment. Altogether, our data not only validates B23/NPM as a main target for CIGB-300 in cancer cells but also provides the first experimental clues to explain their differential antiproliferative response. Importantly, our findings suggest that further improvements to this cell penetrating peptide-based drug should entail its more efficient intracellular delivery at such subcellular localization.
authors.affiliation: Laboratory of Molecular Oncology, Division of Pharmaceuticals, Center for Genetic Engineering and Biotechnology-CIGB, Havana CP10600, Cuba. yasser.perera@cigb.edu.cu
authors.forename: Yasser
authors.initials: Y
authors.lastname: Perera
authors.forename: Heydi C
authors.initials: HC
authors.lastname: Costales
authors.forename: Yakelin
authors.initials: Y
authors.lastname: Diaz
authors.forename: Osvaldo
authors.initials: O
authors.lastname: Reyes
authors.forename: Hernan G
authors.initials: HG
authors.lastname: Farina
authors.forename: Lissandra
authors.initials: L
authors.lastname: Mendez
authors.forename: Roberto E
authors.initials: RE
authors.lastname: Gómez
authors.forename: Boris E
authors.initials: BE
authors.lastname: Acevedo
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Gomez
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Alonso
authors.forename: Silvio E
authors.initials: SE
authors.lastname: Perea
mesh_terms: D000970:Antineoplastic Agents / Q000378:metabolism / Q000494:pharmacology*; D017209:Apoptosis; D047390:Casein Kinase II / Q000037:antagonists & inhibitors; D059447:Cell Cycle Checkpoints; D045744:Cell Line, Tumor; D002466:Cell Nucleolus / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects; D006801:Humans; D020128:Inhibitory Concentration 50; D009687:Nuclear Proteins / Q000378:metabolism; D000090243:Nucleophosmin; D010456:Peptides, Cyclic / Q000378:metabolism / Q000494:pharmacology*; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational / Q000187:drug effects
chemical_list: D000970:Antineoplastic Agents; C000716967:NPM1 protein, human; D009687:Nuclear Proteins; D010456:Peptides, Cyclic; D000090243:Nucleophosmin; D047390:Casein Kinase II; C532510:CIGB-300