Comparative analysis reveals amino acids critical for anticancer activity of peptide CIGB-552

Abstract

Because of resistance development by cancer cells against current anticancer drugs, there is a considerable interest in developing novel antitumor agents. We have previously demonstrated that CIGB-552, a novel cell-penetrating synthetic peptide, was effective in reducing tumor size and increasing lifespan in tumor-bearing mice. Studies of protein-peptide interactions have shown that COMMD1 protein is a major mediator of CIGB-552 antitumor activity. Furthermore, a typical serine-protease degradation pattern for CIGB-552 in BALB/c mice serum was identified, yielding peptides which differ from CIGB-552 in size and physical properties. In the present study, we show the results obtained from a comparative analysis between CIGB-552 and its main metabolites regarding physicochemical properties, cellular internalization, and their capability to elicit apoptosis in MCF-7 cells. None of the analyzed metabolites proved to be as effective as CIGB-552 in promoting apoptosis in MCF-7. Taking into account these results, it seemed important to examine their cell-penetrating capacity and interaction with COMMD1. We show that internalization, a lipid binding-dependent process, is impaired as well as metabolite-COMMD1 interaction, key component of the apoptotic mechanism. Altogether, our results suggest that features conferred by the amino acid sequence are decisive for CIGB-552 biological activity, turning it into the minimal functional unit. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

Cell Penetrating Capacity and Internalization Mechanisms Used by the Synthetic Peptide CIGB-552 and Its Relationship with Tumor Cell Line Sensitivity

“…Interaction between COMMD1 and CIGB-552 has been previously reported by pull down and competitive enzyme-linked immunosorbent assay [ 5 , 10 ]. However, such an interaction has never been demonstrated in a physiological environment such as within cells.…”

“…Such patterns have already been effectively correlated with internalization mechanisms in CIGB-552. We have previously reported the occurrence of endocytosis and transduction as internalization mechanisms for CIGB-552 in the MCF-7 line, where the two patterns were also identified [ 10 ]. Our results show that both patterns are also present in HT-29 and H460, as previously observed for the MCF-7 cell line, though no differences for FLC frequency were found between the cell lines.…”

“…However, differences were also observed between tumor-derived cell lines considering the variability of tissue origin. Specifically, H460 is considered to be one of the most sensitive cell lines, while MCF-7 is considered to be one of the most resistant so far explored ( Table 1 ) [ 5 , 10 ].…”

Cues to Opening Mechanisms From in Silico Electric Field Excitation of Cx26 Hemichannel and in Vitro Mutagenesis Studies in HeLa Transfectans

“…CG simulations were performed using the SIRAH force field (Darré et al, 2015 ) ( www.sirahff.com ), which is sensitive to variations in ionic strength and protein sequence (Surdo et al, 2017 ), and the lipid parameterization presented in Astrada et al ( 2016 ).…”

Antitumour peptide based on a protein derived from the horseshoe crab: CIGB‐552 a promising candidate for cancer therapy

“…The IC 50 values observed in tumour cell lines suggest a tumour type‐dependent pattern of sensitivity. Recently, we demonstrated that this difference is caused by the internalization mechanism for the peptide (Astrada et al, 2016).…”