Practical synthesis of maleimides and coumarin-linked probes for protein and antibody labelling via reduction of native disulfides
作者:Hong Y. Song、Mun H. Ngai、Zhen Y. Song、Paul A. MacAry、Jonathan Hobley、Martin J. Lear
DOI:10.1039/b904060a
日期:——
The cellular tracking, detection and sensing of protein or antibody movement are important aspects to advance our understanding of biomolecular interactions and activity. Antibodies modified with fluorescent dyes are also valuable tools, especially in immunology research. We describe here a proof-of-principle study of a new water-soluble coumarin probe with a maleimide thiol-reacting unit to fluorescently tag biomolecules. Highlights include: (1) a convenient water-based preparation of N-substituted maleimides, (2) a one-pot preparation of activated maleimido-esters, and (3) a bio-conjugation protocol for the selenol-promoted reduction of native disulfide bonds and the ‘site-specific’ labelling of antibodies with no significant loss of activity.
Flavaglines constitute a family of natural anticancer compounds. We present here 3 (FL3), the first synthetic flavagline that inhibits cell proliferation and viability (IC50 approximate to 1 nM) at lower doses than did the parent compound, racemic rocaglaol. Compound 3 enhanced doxorubicin cytotoxicity in HepG2 cells and retained its potency against. adriamycin-resistant cell lines without inducing cardiomyocyte toxicity. Compound 3 induced apoptosis of HL60 and Hela cells by triggering the translocation of Apoptosis Inducing Factor (AIF) and caspase-12 to the nucleus. A fluorescent conjugate of 3 accumulated ill endoplasmic reticulum (ER), suggesting that flavaglines bind to their target in the ER. where it triggers a cascade of events that leads to the translocation of AIF and caspase-12 to the nucleus and probably inhibition of eIF4A. Our studies highlight structural features critical to their antineoplastic potential and suggest that these compounds would retain their activity in cells refractory to caspase activation.