Abstract

The use of pharmacologically active short peptide sequences is a better option in cancer therapeutics than the full-length protein. Here we report one such 44-mer peptide sequence of SMAR1 (TAT-SMAR1 wild type, P44) that retains the tumor suppressor activity of the full-length protein. The protein transduction domain of human immunodeficiency virus, type 1, Tat protein was used here to deliver the 33-mer peptide of SMAR1into the cells. P44 peptide could efficiently activate p53 by mediating its phosphorylation at serine 15, resulting in the activation of p21 and in effect regulating cell cycle checkpoint. In vitro phosphorylation assays with point-mutated P44-derived peptides suggested that serine 347 of SMAR1 was indispensable for its activity and represented the substrate motif for the protein kinase C family of proteins. Using xenograft nude mice models, we further demonstrate that P44 was capable of inhibiting tumor growth by preventing cellular proliferation. P44 treatment to tumor-bearing mice prevented the formation of poorly organized tumor vasculature and an increase in hypoxia-inducible factor-1alpha expression, both being signatures of tumor progression. The chimeric TAT-SMAR1-derived peptide, P44, thus has a strong therapeutic potential as an anticancer drug.Abstract: The p53 and nuclear factor κB (NF-κB) pathways play crucial roles in human cancer development. Simultaneous targeting of both pathways is an attractive therapeutic strategy against cancer. The use of pharmacologically active short peptide sequences has prooven to be a better option in cancer therapeutics than the full-lengthprotein. It has been previously report ed one such 44-mer peptide sequence of SMAR1 (TAT-SMAR1 wild type, P44) that retains the tumor suppressor activity of the full-length protein.P44 peptide could efficiently activate p53 by mediating its phosphorylation at serine15, resulting in the activation of p21 and in effect regulating cell cycle checkpoint. In vitrophosphorylation assays with point-mutated P44-derived pep-tides suggested that serine 347 of SMAR1 was indispensable forits activity and represented the substrate motif for the proteinkinase C family of proteins. In this Research Scientific Project we generated Molecular dynamics and mechanistic in silico discovery simulations of a novel chemo-SMAR1-engineered p53 and NF-κB derived P44 cyclotidomimic agonisitic pharmacoligand P44 dual targeting hyperstructure for the activation of the p53 tumor suppressor pathway.

Keywords

Molecular dynamics simulations, in silico discovery, novel chemo-hyperstructure, drug discovery, dual targeting, NF-κB, pathways, activation, p53 tumor suppressor pathway, engineered, P44 cyclotidomimic, agonisitic, mechanistic, pharmacoligand, Molecular dynamics simulations and drug discovery, Keywords: molecular dynamics simulations, computer-aided drug discovery, cryptic binding sites, allosteric binding sites, virtual screening, free-energy prediction