title: Antibacterial and anticancer activity of a series of novel peptides incorporating cyclic tetra-substituted C(α) amino acids.
abstract: Eleven antimicrobial peptides (AMP) based on the incorporation of cyclic tetra substituted C(α) amino acids, as well as other unnatural amino acids were designed, synthesized and screened for in vitro activity against 18 strains of bacteria as well as 12 cancer cell lines. The AMPs discussed herein are derived from the following peptide sequence: Ac-GF(X)G(X)B(X)G(X)F(X)G(X)GB(X)BBBB-amide, X=any one of the following residues, A5c, A6c, Tic or Oic and B=any one of the following residues, Arg, Lys, Orn, Dpr or Dab. A diversity of in vitro inhibitory activity was observed for these AMPs. Several analogs exhibited single digit μM activity against drug resistant bacteria including; multiple drug resistant Mycobacterium tuberculosis, extremely drug resistant Mycobacterium tuberculosis and MRSA. The physicochemical properties of the basic amino acid residues incorporated into these AMPs seem to play a major role in defining antibacterial activity. Overall hydrophobicity seems to play a limited role in defining antibacterial activity. The ESKAPE pathogens were used to compare the activity of these AMPs to another family of synthetic AMPs incorporating the unnatural amino acids Tic and Oic. In most cases similarly substituted members of both families exhibited similar inhibitory activity against the ESKAPE pathogens. In specific cases differences in activity as high as 15 fold were observed between analogs. In addition four of these AMPs exhibited promising IC50 (<7.5μM) values against 12 different and diverse cancer cell lines. Five other AMPs exhibited promising IC50 (<7.5μM) values against selected cancer cell lines.
authors.affiliation: Department of Chemistry and Physics, Augusta University, College of Science and Mathematics, Augusta, GA, United States(†). Electronic address: rhicks@augusta.edu.
authors.forename: Rickey P
authors.initials: RP
authors.lastname: Hicks
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology*; D000970:Antineoplastic Agents / Q000737:chemistry* / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects; D001424:Bacterial Infections / Q000188:drug therapy; D045744:Cell Line, Tumor; D006801:Humans; D008958:Models, Molecular; D009169:Mycobacterium tuberculosis / Q000187:drug effects; D009369:Neoplasms / Q000188:drug therapy; D010455:Peptides / Q000737:chemistry* / Q000494:pharmacology*; D014376:Tuberculosis / Q000188:drug therapy
chemical_list: D000596:Amino Acids; D000900:Anti-Bacterial Agents; D000970:Antineoplastic Agents; D010455:Peptides
keywords: AMP; Antibacterial; Anticancer; Cyclic tetra-substituted C(α) amino acids; Drug resistant Mycobacterium tuberculosis; Unnatural amino acids