Quercetin arrests human leukemic T-cells in late G1 phase of the cell cycle.
The effect of quercetin, a flavonoid found in many plants, on the proliferation of human leukemic T-cells was analyzed. Quercetin reversibly blocked the cell cycle at a point 3-6 h before the start of DNA synthesis. Expression of the growth-related genes histone H4, cyclin A and B, and p34cdc2 was suppressed in cells blocked with quercetin. Comparison of the quercetin arrest points with those of the cell cycle inhibitors aphidicolin and mimosine revealed a temporal order of arrest points in G1 of quercetin, mimosine, and aphidicolin. Mimosine and aphidicolin did not inhibit the expression of cyclin A or p34cdc2, whereas all three reagents inhibited expression of cyclin B. Low concentrations of the protein inhibitor cycloheximide inhibited release of the quercetin but not the mimosine or aphidicolin block. A [35S]methionine-labeled M(r) 60,000 protein disappeared in quercetin-treated cells and was rapidly synthesized after removal of quercetin, suggesting the possibility that the M(r) 60,000 protein induces DNA synthesis after the cell is released from a quercetin block. These results suggest the usefulness of quercetin in studies of the regulation of late G1 phase.
Yoshida
M
M
Wistar Institute of Anatomy and Biology, Philadelphia, Pennsylvania 19104.
Yamamoto
M
M
Nikaido
T
T
D016590:Aphidicolin / Q000494:pharmacology; D016203:CDC2 Protein Kinase / Q000032:analysis; D016213:Cyclins / Q000187:drug effects; D003513:Cycloheximide / Q000494:pharmacology; D004273:DNA, Neoplasm / Q000032:analysis* / Q000096:biosynthesis; D005434:Flow Cytometry; D016193:G1 Phase / Q000187:drug effects*; D006657:Histones / Q000032:analysis; D006801:Humans; D015458:Leukemia, T-Cell / Q000378:metabolism / Q000473:pathology*; D008898:Mimosine / Q000494:pharmacology; D011794:Quercetin / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D012333:RNA, Messenger / Q000032:analysis; D012334:RNA, Neoplasm / Q000032:analysis; D016196:S Phase; D013997:Time Factors; D014407:Tumor Cells, Cultured
D016213:Cyclins; D004273:DNA, Neoplasm; D006657:Histones; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D016590:Aphidicolin; D008898:Mimosine; D003513:Cycloheximide; D011794:Quercetin; D016203:CDC2 Protein Kinase