Synthetic Analogue of Rocaglaol Displays a Potent and Selective Cytotoxicity in Cancer Cells: Involvement of Apoptosis Inducing Factor and Caspase-12

Abstract

Flavaglines constitute a family of natural anticancer compounds. We present here 3 (FL3), the first synthetic flavagline that inhibits cell proliferation and viability (IC(50) approximately 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 in 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.