1.Sequence-specific DNA alkylation targeting for Kras codon 13 mutation by pyrrole-imidazole polyamide seco-CBI conjugates.
Taylor RD1, Asamitsu S, Takenaka T, Yamamoto M, Hashiya K, Kawamoto Y, Bando T, Nagase H, Sugiyama H. Chemistry. 2014 Jan 27;20(5):1310-7. doi: 10.1002/chem.201303295. Epub 2013 Dec 30.
Hairpin N-methylpyrrole-N-methylimidazole polyamide seco-CBI conjugates 2-6 were designed for synthesis by Fmoc solid-phase synthesis, and their DNA-alkylating activities against the Kras codon 13 mutation were compared by high-resolution denaturing gel electrophoresis with 225 base pair (bp) DNA fragments. Conjugate 5 had high reactivity towards the Kras codon 13 mutation site, with alkylation occurring at the A of the sequence 5'-ACGTCACCA-3' (site 2), including minor 1 bp-mismatch alkylation against wild type 5'-ACGCCACCA-3' (site 3). Conjugate 6, which differs from conjugate 5 by exchanging one Py unit with a β unit, showed high selectivity but only weakly alkylated the A of 5'-ACGTCACCA-3' (site 2). The hairpin polyamide seco-CBI conjugate 5 thus alkylates according to Dervan's pairing rule with the pairing recognition which β/β pair targets T-A and A-T pairs. SPR and a computer-minimized model suggest that 5 binds to the target sequence with high affinity in a hairpin conformation, allowing for efficient DNA alkylation.
2.Synthesis of Mannosylated Lipopeptides with Receptor Targeting Properties.
Sedaghat B, Stephenson RJ, Giddam AK, Eskandari S, Apte SH1, Pattinson DJ1, Doolan DL1, Toth I2. Bioconjug Chem. 2016 Mar 16;27(3):533-48. doi: 10.1021/acs.bioconjchem.5b00547. Epub 2016 Jan 25.
Present on the surface of antigen presenting cells (APCs), the mannose receptor (MR) has long been recognized as a front-line receptor in pathogen recognition. During the past decade many attempts have been made to target this receptor for applications including vaccine and drug development. In the present study, a library of vaccine constructs comprising fluorescently labeled mannosylated lipid-dendrimers that contained the ovalbumin CD4(+) epitope, OVA323-339, as the model peptide antigen were synthesized using fluorenylmethyloxycarbonyl (Fmoc) solid phase peptide synthesis (SPPS). The vaccine constructs were designed with an alanine spacer between the O-linked mannose moieties to investigate the impact of distance between the mannose units on receptor-mediated uptake and/or binding in APCs. Uptake studies performed on F4/80(+) and CD11c(+) cells showed significant uptake and/or binding for lipopeptides containing mannose, and also the lipopeptide without mannose when compared to the control peptides (peptide with no lipid and peptide with no mannose and no lipid).
3.Facile synthesis of mono- and bis-methylated Fmoc-Dap, -Dab and -Orn amino acids.
Lindahl F1, Hoang HN, Fairlie DP, Cooper MA. Chem Commun (Camb). 2015 Mar 14;51(21):4496-8. doi: 10.1039/c4cc09780g.
A new methodology for the synthesis of side chain mono- or bis-methylated Fmoc-Dap, -Dab and -Orn amino acids was developed by probing the reactivity of commercially available Fmoc amino acids.
4.Solid-Phase Synthesis of Duocarmycin Analogues and the Effect of C-Terminal Substitution on Biological Activity.
Stephenson MJ, Howell LA, O'Connell MA, Fox KR1, Adcock C2, Kingston J2, Sheldrake H3, Pors K3, Collingwood SP2, Searcey M. J Org Chem. 2015 Oct 2;80(19):9454-67. doi: 10.1021/acs.joc.5b01373. Epub 2015 Sep 30.
The duocarmycins are potent antitumor agents with potential for use in the development of antibody-drug conjugates (ADCs) as well as being clinical candidates in their own right. In this article, we describe the synthesis of a duocarmycin monomer (DSA) that is suitably protected for utilization in solid-phase synthesis. The synthesis was performed on a large scale, and the resulting racemic protected Fmoc-DSA subunit was separated by supercritical fluid chromatography (SFC) into the single enantiomers; its application to solid-phase synthesis methodology gave a series of monomeric and extended duocarmycin analogues with amino acid substituents. The DNA sequence selectivity was similar to that in previous reports for both the monomeric and extended compounds. Substitution at the C-terminus of duocarmycin caused a decrease in antiproliferative activity for all of the compounds studied. An extended compound containing an alanine at the C-terminus was converted to the primary amide or to an extended structure containing a terminal tertiary amine, but this had no beneficial effects on biological activity.
