Synthesis of a novel legumain-cleavable colchicine prodrug with cell-specific toxicity.
Conventional chemotherapy has undesirable toxic side-effects to healthy tissues due to low cell selectivity of cytotoxic drugs. One approach to increase the specificity of a cytotoxic drug is to make a less toxic prodrug which becomes activated at the tumour site. The cysteine protease legumain have remarkable restricted substrate specificity and is the only known mammalian asparaginyl (Asn) endopeptidase. Over-expression of legumain is reported in cancers and unstable atherosclerotic plaques, and utilizing legumain is a promising approach to activate prodrugs. In this study we have synthesized the legumain-cleavable peptide sequence N-Boc-Ala-Ala-Asn-Val-OH. The peptide was subsequently conjugated to deacetyl colchicine during three steps to produce Suc-Ala-Ala-Asn-Val-colchicine (prodrug) with >90% chemical purity. Several cell lines with different expressions and activities of legumain were used to evaluate the general toxicity, specificity and efficacy of the microtubule inhibitor colchicine, valyl colchicine and the legumain-cleavable colchicine prodrug. The prodrug was more toxic to the colorectal cancer HCT116 cells (expressing both the 36kDa active and 56kDa proform of legumain) than SW620 cells (only expressing the 56kDa prolegumain) indicating a relationship between toxicity of the prodrug and activity of legumain in the cells. Also, in monoclonal legumain over-expressing HEK293 cells the prodrug toxicity was higher compared to native HEK293 cells. Furthermore, co-administration of the prodrug either with the potent legumain inhibitor cystatin E/M or the endocytosis inhibitor Dyngo-4a inhibited cell death, indicating that the prodrug toxicity was dependent on both asparaginyl endopeptidase activity and endocytosis. This colchicine prodrug adds to a legumain-activated prodrug strategy approach and could possibly be of use both in targeted anticancer and anti-inflammatory therapy.
Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, PO Box 1068 Blindern, N-0316 Oslo, Norway. Electronic address: Robert.smith@farmasi.uio.no.
Robert Løvsletten
RL
Smith
Department of Pharmaceutical Chemistry, School of Pharmacy, University of Oslo, Norway.
Ove Alexander Høgmoen
OA
Åstrand
Department of Pharmaceutical Chemistry, School of Pharmacy, University of Oslo, Norway.
Luan Minh
LM
Nguyen
Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, PO Box 1068 Blindern, N-0316 Oslo, Norway.
Tina
T
Elvestrand
Aquila Pharma Services AS, Arnulf Øverlands vei 185, 0763 Oslo, Norway.
Gunnar
G
Hagelin
Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, PO Box 1068 Blindern, N-0316 Oslo, Norway.
Rigmor
R
Solberg
Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, PO Box 1068 Blindern, N-0316 Oslo, Norway.
Harald Thidemann
HT
Johansen
Department of Pharmaceutical Chemistry, School of Pharmacy, University of Oslo, Norway.
Pål
P
Rongved
D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D003078:Colchicine / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D003546:Cysteine Endopeptidases / Q000737:chemistry*; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor; D045325:HCT116 Cells; D057809:HEK293 Cells; D006801:Humans; D015394:Molecular Structure; D011355:Prodrugs / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D014407:Tumor Cells, Cultured; D000099240:Asparaginyl Endopeptidase
D003078:Colchicine; D003546:Cysteine Endopeptidases; D011355:Prodrugs; D000099240:Asparaginyl Endopeptidase
Asparaginyl endopeptidase; Colchicine; Colorectal cancer; Cystatin E/M; Legumain; Prodrug