Aminoflavone induces oxidative DNA damage and reactive oxidative species-mediated apoptosis in breast cancer cells.
Aminoflavone (5-amino-2-(4-amino-3-fluorophenyl)-6,8-difluoro-7-methylchromen-4-one; AF; NSC 686288), a novel anticancer candidate agent, is undergoing clinical evaluation. AF induces DNA-protein cross-links (DPCs), Gamma-H2AX phosphorylation, aryl hydrocarbon receptor (AhR) signaling, apoptosis and its own metabolism via cytochrome P4501A1 and 1A2 (CYP1A1/1A2) activation in sensitive estrogen receptor positive (ER+) MCF7 breast cancer cells. Estrogen receptor negative (ER-) breast cancer is typically more aggressive with a poorer prognosis. In this investigation, we evaluated the ability of AF to induce reactive oxygen species (ROS) formation, oxidative DNA damage and apoptosis in ER- MDA-MB-468 breast cancer cells. The antioxidant, N-acetyl-L-cysteine (NAC), attenuated the cytotoxic effects of AF in MDA-MB-468 cells; an effect is also observed in ER+ T47D breast cancer cells. Nonmalignant MCF10A breast epithelial cells were resistant to the cytotoxic effects of AF. AF increased intracellular ROS, an effect blocked by NAC and the CYP1A1/1A2 inhibitor, alpha-Naphthoflavone (alpha-NF). AF induced oxidative DNA damage as evidenced by increased 8-oxo-7,8-dihydroguanine (8-oxodG) levels and DPC formation in these cells. AF caused S-phase arrest corresponding to an increase in p21((waf1/cip1)) protein expression. AF induced caspase 3, 8 and 9 activation, caspase-dependent apoptotic body formation and poly [ADP-ribose] polymerase (PARP) cleavage. Pretreatment with the pan-caspase inhibitor, benzyloxycarbonyl-Val-Ala-DL-Asp(OMe)-fluoromethylketone inhibited apoptosis and partially inhibited ROS formation and oxidative DNA damage. Pretreatment with NAC attenuated AF-induced apoptotic body formation and caspase 3 activation. These studies suggest AF inhibits the growth of breast cancer cells in part, by inducing ROS production, oxidative DNA damage and apoptosis and has the potential to treat hormone-independent breast cancer.
Department of Biochemistry and Microbiology, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA.
Lancelot
L
McLean
Ubaldo
U
Soto
Keli
K
Agama
Jawad
J
Francis
Randi
R
Jimenez
Yves
Y
Pommier
Lawrence
L
Sowers
Eileen
E
Brantley
D000111:Acetylcysteine / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000737:chemistry / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology*; D020169:Caspases / Q000378:metabolism; D019363:Cytochrome P-450 CYP1A1 / Q000378:metabolism; D019388:Cytochrome P-450 CYP1A2 / Q000378:metabolism; D004249:DNA Damage / Q000187:drug effects*; D004273:DNA, Neoplasm / Q000187:drug effects*; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D005419:Flavonoids / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D016166:Free Radical Scavengers / Q000494:pharmacology; D006801:Humans; D017382:Reactive Oxygen Species / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000032:analysis; D016196:S Phase / Q000187:drug effects
D000970:Antineoplastic Agents; D004273:DNA, Neoplasm; D005419:Flavonoids; D016166:Free Radical Scavengers; D017382:Reactive Oxygen Species; D011960:Receptors, Estrogen; C413760:aminoflavone; D019363:Cytochrome P-450 CYP1A1; D019388:Cytochrome P-450 CYP1A2; D020169:Caspases; D000111:Acetylcysteine