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Offerman SC, Kadirvel M, Abusara OH, Bryant JL, Telfer BA, Brown G, Freeman S, White A, Williams KJ, Aojula HS. N-tert-Prenylation of the indole ring improves the cytotoxicity of a short antagonist G analogue against small cell lung cancer. Medchemcomm 2017; 8:551-558. [PMID: 30108771 PMCID: PMC6072501 DOI: 10.1039/c6md00691d] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 02/10/2017] [Indexed: 11/21/2022]
Abstract
Natural prenylated indoles have been proposed as potential anticancer agents. To exploit this discovery for developing new peptide therapeutics, we report the first studies whereby incorporation of prenylated indoles into primary sequences has been achieved. We developed a route to synthesise Nα-Fmoc-protected tryptophan derivatives in which the prenyl group is linked to the N-indole core, using Pd(ii)-mediated C-H functionalisation of 2-methyl-2-butene. Based on the Substance P antagonist G (SPG), a well-known Small Cell Lung Cancer (SCLC) anticancer agent, we designed a new penta-peptide sequence to include a prenyl moiety on one of the tryptophan residues. The N-tert-prenylated tryptophan analogue was assembled into the pentameric peptide using standard solid phase peptide synthesis or liquid phase synthesis by fragment coupling. In vitro screening showed that the N-tert-prenylation of the indole ring on the tryptophan residue located near the C-terminal of the penta-peptide enhanced the cytotoxicity against H69 (IC50 = 2.84 ± 0.14 μM) and DMS79 (IC50 = 4.37 ± 0.44 μM) SCLC cell lines when compared with the unmodified penta-peptide (H69, IC50 = 30.74 ± 0.30 μM and DMS79, IC50 = 23.00 ± 2.07 μM) or the parent SPG sequence (IC50 > 30 μM, both cell lines). SCLC almost invariably relapses with therapy-resistant disease. The DMS79 cell line was established from a patient following treatment with a number of chemotherapeutics (cytoxan, vincristine and methotrexate) and radiation therapy. Treating DMS79 tumour-bearing nude mice provided a human xenograft model of drug resistance to test the efficacy of the prenylated peptide. A low dose (1.5 mg kg-1) of the prenylated peptide was found to reduce tumour growth by ∼30% (P < 0.05) at day 7, relative to the control group receiving vehicle only. We conclude that the availability of the Fmoc-Trp(N-tert-prenyl)-OH amino acid facilitates the synthesis of prenylated-tryptophan-containing peptides to explore their therapeutic potential.
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Affiliation(s)
- Shaun C Offerman
- Division of Pharmacy and Optometry , School of Health Sciences , Manchester Academic Health Sciences Centre , University of Manchester , Manchester , M13 9PL , UK .
| | - Manikandan Kadirvel
- CRUK-EPSRC Cancer Imaging Centre in Cambridge and Manchester , Manchester , M20 3LJ , UK
| | - Osama H Abusara
- Division of Pharmacy and Optometry , School of Health Sciences , Manchester Academic Health Sciences Centre , University of Manchester , Manchester , M13 9PL , UK .
| | - Jennifer L Bryant
- Division of Pharmacy and Optometry , School of Health Sciences , Manchester Academic Health Sciences Centre , University of Manchester , Manchester , M13 9PL , UK .
| | - Brian A Telfer
- Division of Pharmacy and Optometry , School of Health Sciences , Manchester Academic Health Sciences Centre , University of Manchester , Manchester , M13 9PL , UK .
| | - Gavin Brown
- CRUK-EPSRC Cancer Imaging Centre in Cambridge and Manchester , Manchester , M20 3LJ , UK
| | - Sally Freeman
- Division of Pharmacy and Optometry , School of Health Sciences , Manchester Academic Health Sciences Centre , University of Manchester , Manchester , M13 9PL , UK .
| | - Anne White
- Division of Diabetes, Endocrinology & Gastroenterology , School of Medical Sciences , Faculty of Biology, Medicine, & Health , Manchester Academic Health Sciences Centre , University of Manchester , Manchester , M13 9PL , UK
| | - Kaye J Williams
- Division of Pharmacy and Optometry , School of Health Sciences , Manchester Academic Health Sciences Centre , University of Manchester , Manchester , M13 9PL , UK .
- CRUK-EPSRC Cancer Imaging Centre in Cambridge and Manchester , Manchester , M20 3LJ , UK
| | - Harmesh S Aojula
- Division of Pharmacy and Optometry , School of Health Sciences , Manchester Academic Health Sciences Centre , University of Manchester , Manchester , M13 9PL , UK .
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Offerman SC, Kamra Verma AV, Telfer BA, Berk DA, Clarke DJ, Aojula HS. Ability of co-administered peptide liposome nanoparticles to exploit tumour acidity for drug delivery. RSC Adv 2014. [DOI: 10.1039/c3ra44746d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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