Loaiza-Pérez Andrea I, Kenney Susan, Boswell Jamie, Hollingshead Melinda, Alley Michael C, Hose Curtis, Ciolino Henry P, Yeh Grace C, Trepel Jane B, Vistica David T, Sausville Edward A
Developmental Therapeutics Program, Division of Cancer Treatment and Diagnosis, National Cancer Institute-Frederick, Building 322, Room 104, Frederick, MD 21702, USA.
Mol Cancer Ther. 2004 Jun;3(6):715-25.
Aminoflavone (4H-1-benzopyran-4-one, 5-amino-2-(4-amino-3-fluorophenyl)-6,8-difluoro-7-methyl; NSC 686288) demonstrates differential antiproliferative activity in the National Cancer Institute's anticancer drug screen. We demonstrate here that MCF-7 human breast cancer cells are sensitive to aminoflavone both in vitro and when grown in vivo as xenografts in athymic mice. As previous work has indicated that aminoflavone requires metabolic activation by cytochrome P450 1A1 (CYP1A1), we investigated the effect of aminoflavone on CYP1A1 expression and on the aryl hydrocarbon receptor (AhR), a transcriptional regulator of CYP1A1. In aminoflavone-sensitive but not aminoflavone-resistant cells, the drug caused a 100-fold induction of CYP1A1 mRNA and a corresponding increase in ethoxyresorufin-O-deethylase activity. An AhR-deficient variant of the MCF-7 breast carcinoma, AH(R100), with diminished CYP1A1 inducibility, exhibits cellular resistance to aminoflavone and is refractory to CYP1A1 mRNA induction by the drug. The increase in CYP1A1 mRNA in the aminoflavone-sensitive MCF-7 breast tumor cell results from transcriptional activation of xenobiotic-responsive element (XRE)-controlled transcription. Aminoflavone treatment causes a translocation of the AhR from the cytoplasm to the nucleus with subsequent formation of AhR-XRE protein DNA complexes. In contrast to the aminoflavone-sensitive MCF-7 cells, the resistant cell lines (MDA-MB-435, PC-3, and AH(R100)) demonstrated constitutive nuclear localization of AhR. Additionally, aminoflavone failed to induce ethoxyresorufin-O-deethylase activity, CYP1A1 transcription, AhR-XRE complex formation, and apoptosis in aminoflavone-resistant cells. These results suggest that the cytotoxicity of aminoflavone in a sensitive breast tumor cell line is the result of the engagement of AhR-mediated signal transduction.
氨基黄酮（4H-1-苯并吡喃-4-酮，5-氨基-2-(4-氨基-3-氟苯基)-6,8-二氟-7-甲基；NSC 686288）在美国国立癌症研究所的抗癌药物筛选中表现出不同的抗增殖活性。我们在此证明，MCF-7人乳腺癌细胞在体外以及作为无胸腺小鼠体内异种移植生长时对氨基黄酮敏感。由于先前的研究表明氨基黄酮需要细胞色素P450 1A1（CYP1A1）进行代谢激活，我们研究了氨基黄酮对CYP1A1表达以及对CYP1A1的转录调节因子芳烃受体（AhR）的影响。在对氨基黄酮敏感而非耐药的细胞中，该药物导致CYP1A1 mRNA诱导了100倍，并且乙氧异吩唑酮-O-脱乙基酶活性相应增加。MCF-7乳腺癌的AhR缺陷变体AH(R100)，其CYP1A1诱导性降低，对氨基黄酮表现出细胞抗性，并且对该药物诱导的CYP1A1 mRNA不敏感。氨基黄酮敏感的MCF-7乳腺肿瘤细胞中CYP1A1 mRNA的增加源于外源性反应元件（XRE）控制转录的转录激活。氨基黄酮处理导致AhR从细胞质转运到细胞核，随后形成AhR-XRE蛋白-DNA复合物。与对氨基黄酮敏感的MCF-7细胞相反，耐药细胞系（MDA-MB-435、PC-3和AH(R100)）显示AhR的组成型核定位。此外，氨基黄酮未能在对氨基黄酮耐药的细胞中诱导乙氧异吩唑酮-O-脱乙基酶活性、CYP1A1转录、AhR-XRE复合物形成和细胞凋亡。这些结果表明，氨基黄酮在敏感乳腺肿瘤细胞系中的细胞毒性是AhR介导的信号转导参与的结果。
