N-hydroxy-N'-(3,4,5-trimethoxyphenyl)-3,4,5-trimethoxy-benzamidine, a novel resveratrol analog, inhibits ribonucleotide reductase in HL-60 human promyelocytic leukemia cells: synergistic antitumor activity with arabinofuranosylcytosine.
Resveratrol (3,4',5,-trihydroxystilbene, RV), an ingredient of wine, exhibits a broad spectrum of antiproliferative effects against human cancer cells. In order to develop a derivative with comparable effects, we modified the molecule by introducing additional methoxyl groups. The resulting novel RV analog, N-hydroxy-N'-(3,4,5-trimethoxyphenyl)-3,4,5-trimethoxybenzamidine (KITC), was investigated in HL-60 human promyelocytic leukemia cells. The induction of apoptosis was determined employing a specific Hoechst/propidium iodide double staining method and cell cycle distribution was evaluated by FACS. KITC's influence on the concentration of deoxyribonucleoside triphosphates, the products of ribonucleotide reductase (RR), was determined using the HPLC method. In addition, we analyzed the effects of KITC treatment on the incorporation of 14C-cytidine into the DNA of tumor cells in order to quantify the loss of RR in situ activity. To reveal a potential value of KITC for supporting conventional chemotherapy, we also examined whether a combination of KITC with arabinofuranosylcytosine (Ara-C) could yield synergistic growth inhibitory effects. KITC caused a dose-dependent induction of apoptosis, whereas no remarkable changes of the cell cycle distribution were observed. Incubation with KITC resulted in a significant depletion of intracellular dTTP and dATP pools and was also found to remarkably reduce the in situ activity of RR, the key enzyme of de novo DNA synthesis. In addition, KITC exhibited synergistic combination effects when applied sequentially with Ara-C. Due to these promising results, KITC deserves further preclinical and in vivo testing.
Saiko
Philipp
P
Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Vienna, General Hospital of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria.
Ozsvar-Kozma
Maria
M
Bernhaus
Astrid
A
Jaschke
Margit
M
Graser
Geraldine
G
Lackner
Andreas
A
Grusch
Michael
M
Horvath
Zsuzsanna
Z
Madlener
Sibylle
S
Krupitza
Georg
G
Handler
Norbert
N
Erker
Thomas
T
Jaeger
Walter
W
Fritzer-Szekeres
Monika
M
Szekeres
Thomas
T
D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002453:Cell Cycle / Q000187:drug effects; D003561:Cytarabine / Q000494:pharmacology*; D003562:Cytidine / Q000378:metabolism; D004357:Drug Synergism; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D018922:HL-60 Cells; D006801:Humans; D000077185:Resveratrol; D012264:Ribonucleotide Reductases / Q000037:antagonists & inhibitors*; D013267:Stilbenes / Q000494:pharmacology*
D000970:Antineoplastic Agents; D004791:Enzyme Inhibitors; C525082:N-hydroxy-N'-(3,4,5-trimethoxyphenyl)-3,4,5-trimethoxy-benzamidine; D013267:Stilbenes; D003561:Cytarabine; D003562:Cytidine; D012264:Ribonucleotide Reductases; D000077185:Resveratrol