Mitani Takakazu, Ito Yuta, Harada Naoki, Nakano Yoshihisa, Inui Hiroshi, Ashida Hitoshi, Yamaji Ryoichi
Division of Applied Life Sciences, Graduate School of Life and Environmental Sciences, Osaka Prefecture University.
J Nutr Sci Vitaminol (Tokyo). 2014;60(2):122-8. doi: 10.3177/jnsv.60.122.
Resveratrol (3,4',5-trihydroxy-trans-stilbene) is known to enhance the cytotoxicity of the anticancer drug doxorubicin. On the other hand, breast cancer MCF-7 cells acquire resistance to doxorubicin under hypoxic conditions. In this study, we investigated the effect of resveratrol on hypoxia-induced resistance to doxorubicin in MCF-7 cells. Resveratrol and its derivative 3,5-dihydroxy-4'-methoxy-trans-stilbene, but not 3,5-dimethoxy-4'-hydroxy-trans-stilbene, cancelled hypoxia-induced resistance to doxorubicin at a concentration of 10 μM. Carbonyl reductase 1 (CBR1) catalyzes the conversion of doxorubicin to its metabolite doxorubicinol, which is much less effective than doxorubicin. Hypoxia increased the expression of CBR1 at both mRNA and protein levels, and knockdown of CBR1 inhibited hypoxia-induced resistance to doxorubicin in MCF-7 cells. Knockdown of hypoxia-inducible factor (HIF)-1α repressed the hypoxia-induced expression of CBR1. Resveratrol repressed the expression of HIF-1α protein, but not HIF-1α mRNA, and decreased hypoxia-activated HIF-1 activity. Resveratrol repressed the hypoxia-induced expression of CBR1 at both mRNA and protein levels. Likewise, 3,5-dihydroxy-4'-methoxy-trans-stilbene decreased the hypoxia-induced expression of CBR1 protein, but not 3,5-dimethoxy-4'-hydroxy-trans-stilbene. Furthermore, resveratrol decreased the expression of HIF-1α protein even in the presence of the proteasome inhibitor MG132 in hypoxia. Theses results indicate that in MCF-7 cells, HIF-1α-increased CBR1 expression plays an important role in hypoxia-induced resistance to doxorubicin and that resveratrol and 3,5-dihydroxy-4'-methoxy-trans-stilbene decrease CBR1 expression by decreasing HIF-1α protein expression, perhaps through a proteasome-independent pathway, and consequently repress hypoxia-induced resistance to doxorubicin.
白藜芦醇（3,4',5-三羟基反式芪）已知可增强抗癌药物阿霉素的细胞毒性。另一方面，乳腺癌MCF-7细胞在缺氧条件下会对阿霉素产生耐药性。在本研究中，我们调查了白藜芦醇对MCF-7细胞缺氧诱导的阿霉素耐药性的影响。白藜芦醇及其衍生物3,5-二羟基-4'-甲氧基反式芪，而非3,5-二甲氧基-4'-羟基反式芪，在浓度为10μM时可消除缺氧诱导的阿霉素耐药性。羰基还原酶1（CBR1）催化阿霉素转化为其代谢产物阿霉素醇，阿霉素醇的效果远不如阿霉素。缺氧在mRNA和蛋白质水平上均增加了CBR1的表达，而敲低CBR1可抑制MCF-7细胞中缺氧诱导的阿霉素耐药性。敲低缺氧诱导因子（HIF）-1α可抑制缺氧诱导的CBR1表达。白藜芦醇可抑制HIF-1α蛋白的表达，但不影响HIF-1α mRNA，并降低缺氧激活的HIF-1活性。白藜芦醇在mRNA和蛋白质水平上均抑制缺氧诱导的CBR1表达。同样，3,5-二羟基-4'-甲氧基反式芪可降低缺氧诱导的CBR1蛋白表达，但3,5-二甲氧基-4'-羟基反式芪则无此作用。此外，即使在缺氧条件下存在蛋白酶体抑制剂MG132时，白藜芦醇仍可降低HIF-1α蛋白的表达。这些结果表明，在MCF-7细胞中，HIF-1α增加的CBR1表达在缺氧诱导的阿霉素耐药性中起重要作用，并且白藜芦醇和3,5-二羟基-4'-甲氧基反式芪可能通过蛋白酶体非依赖途径降低HIF-1α蛋白表达，从而降低CBR1表达，进而抑制缺氧诱导的阿霉素耐药性。
