Structural permutation of potent cytotoxin, polytheonamide B: discovery of cytotoxic Peptide with altered activity - PubMed (original) (raw)

Structural permutation of potent cytotoxin, polytheonamide B: discovery of cytotoxic Peptide with altered activity

Hiroaki Itoh et al. ACS Med Chem Lett. 2012.

Abstract

Polytheonamide B (1) is an ion-channel forming natural peptide with a d,l-alternating 48 amino acid sequence, which is an exceedingly potent cytotoxin. We recently designed and synthesized a simplified dansylated polytheonamide mimic 2, in which six amino acid residues were modified from 1, and demonstrated that 2 emulated the functions of 1. Here we report a comprehensive structure-activity relationship study of substructures of 2. A unified synthetic strategy was developed for highly automated syntheses of 13 peptide sequences of 27 to 39 amino acid residues, and the artificial 37-mer peptide 6 was discovered to be significantly more toxic than the other 12 compounds toward P388 mouse leukemia cells (IC50 = 3.7 nM). Ion exchange activity experiments of 6 using the liposome and P388 cells both demonstrated that 6 did not possess ion-channel activity, strongly suggesting that 6 exerted its potent cytoxicity through a distinct mode of action from 1 and 2.

Keywords: Cytotoxic agents; natural products; solid-phase synthesis; structure−activity relationships; synthetic ion channels.

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Figures

Figure 1

Figure 1

Structures of polytheonamide B, dansylated polytheonamide mimic, and gramicidin D.

Scheme 1

Scheme 1. Representative Synthetic Scheme of the Substructures of 2

Figure 2

Figure 2

Time-course of H+/Na+ exchange across lipid bilayers of pH-gradient liposomes (EYPC/cholesterol = 2:1) caused by 1, 2, 3, and 6. The ion transport was evaluated as the pH-dependent fluorescence from pyranine standardized against the maximum exchange by Triton X-100. In all the experiments, the peptides were added at 60 s.

Figure 3

Figure 3

Structures of BCECF-AM (20) and BCECF (21).

Figure 4

Figure 4

Time-course of H+/Na+ exchange across cell membranes of the P388 leukemia cells caused by 1, 3, and 6. Intracellular pH values were evaluated by the pH-dependent fluorescence of 21. In all the experiments, peptides were added at 0 s.

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References

    1. Hamada T.; Matsunaga S.; Yano G.; Fusetani N. Polytheonamides A and B, Highly Cytotoxic, Linear Polypeptides with Unprecedented Structural Features, from the Marine Sponge Theonella swinhoei. J. Am. Chem. Soc. 2005, 127, 110–118. - PubMed
    1. Hamada T.; Sugawara T.; Matsunaga S.; Fusetani N. Polytheonamides, Unprecedented Highly Cytotoxic Polypeptides, from the Marine Sponge Theonella swinhoei: 1. Isolation and Component Amino Acids. Tetrahedron Lett. 1994, 35, 719–720.
    1. Hamada T.; Matsunaga S.; Fujiwara M.; Fujita K.; Hirota H.; Schmucki R.; Güntert P.; Fusetani N. Solution Structure of Polytheonamide B, a Highly Cytotoxic Nonribosomal Polypeptide from Marine Sponge. J. Am. Chem. Soc. 2010, 132, 12941–12945. - PubMed
    1. Iwamoto M.; Shimizu H.; Muramatsu I.; Oiki S. A Cytotoxic Peptide from a Marine Sponge Exhibits Ion Channel Activity through Vectorial-Insertion into the Membrane. FEBS Lett. 2010, 584, 3995–3999. - PubMed
    1. Oiki S.; Muramatsu I.; Matsunaga S.; Fusetani N.. A Channel-Forming Peptide Toxin: Polytheonamide from Marine Sponge (Theonella swinhoei). Folia Pharmacol. Jpn. 1997, 110(Suppl.1), 195–198. - PubMed

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