MOLECULAR MECHANISMS IN THE ANTIPROLIFERATIVE ACTION OF QUERCETIN

A single treatment with quercetin (5.5 mu M), a plant flavonoid, activ ated both apoptosis and differentiation programs in K562 human leukemi a cells. K562 cells expressed commitment to apoptosis after 1 h exposu re, however, at least 12 h of drug exposure was needed to induce diffe rentiation. Early (1 h) downregulation of the c-myc and Ki-ras oncogen es and rapid reduction of inositol-1,4,5-trisphosphate (IP3) concentra tion (IC50 = 9 mu M, 1 h incubation) are part of the antiproliferative action of quercetin and appear to relate to induction of differentiat ion and/or apoptotic program of K562 leukemia cells treated with querc etin.