Nitric oxide-mediated regulation of chemosensitivity in cancer cells
Nitric oxide-mediated regulation of chemosensitivity in cancer cells
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DOI：
10.1093/jnci/93.24.1879
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发表时间：
2001-12-19
期刊：
影响因子：
--
通讯作者：
Graham, CH
中科院分区：
文献类型：
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作者：
Matthews, NE;Adams, MA;Graham, CH
背景：肿瘤中的缺氧与恶性进展、转移扩散以及对放疗和化疗的抵抗力增加有关。分子Oz是细胞通过NO合酶（NOS）产生一氧化氮（NO）所必需的，并且NO可以阻断对缺氧的适应性反应的组分。因此，我们假设缺氧通过抑制内源性NO的产生而增加肿瘤细胞的耐药性。研究方法：将人乳腺癌（MDA-MB-231）和小鼠黑色素瘤（B16 F10）细胞预先暴露于20%O-2、5%O-2或1%O-2中，与内源性NO产生的药理学抑制剂一起孵育，然后用化疗剂处理。通过集落形成试验评估耐药性，并使用蛋白质印迹分析来测量NOS蛋白水平。所有P值均为双侧。结果如下：与在20%O-2中孵育相比，在1%O-2中孵育MDAMB-231肿瘤细胞使其对阿霉素和5-氟尿嘧啶的耐药性分别最大程度地增加了8.5倍（P =.002）和2.3倍（P = .002）。B16 F10小鼠黑色素瘤细胞在1%O-2（与20%O-2）中预孵育12小时后，对阿霉素的耐药性增加了两倍（P <0.001）。MDA-MB-231细胞与NOS抑制剂NG-单甲基-L-精氨酸孵育12小时，可模拟暴露于1%O-2后快速获得耐药性（增加5倍; P <0.001）。相反地，在MDA-MB-231细胞中，通过使用NO模拟物三硝酸甘油酯（GTN）和二亚乙基三胺NO加合物来替代NO活性，分别使耐药性的发展产生统计学显著的衰减59%（P <.001）和40%（P < .001）。用GTN处理B16 F10细胞产生58%的抗性降低（P <0.001）。MDA-MB-231细胞表达的NOS酶的所有三种亚型的水平，暴露于缺氧不改变。结论：NO介导肿瘤细胞的化学敏感性，并且低氧诱导的耐药性似乎部分地由内源性NO产生的下游抑制引起。这些结果提高了小剂量NO模拟物给药可用作化疗辅助的可能性。
Background: Hypoxia in tumors is associated with malignant progression, metastatic spread, and increased resistance to radiotherapy and chemotherapy. Molecular Oz, is required for the cellular production of nitric oxide (NO) by the enzyme NO synthase (NOS), and NO may block components of the adaptive response to hypoxia. Hence, we hypothesized that hypoxia increases drug resistance in tumor cells by inhibiting endogenous NO production. Methods: Human breast carcinoma (MDA-MB-231) and mouse melanoma (B16F10) cells were preexposed to 20% O-2, 5% O-2, or 1% O-2, incubated with a pharmacologic inhibitor of endogenous NO production, and then treated with chemotherapeutic agents. Resistance was assessed by colony-formation assays, and western blot analysis was used to measure NOS protein levels. All P values were two-sided. Results: Incubation of MDAMB-231 tumor cells in 1% O-2 maximally increased their resistance to doxorubicin and 5-fluorouracil by 8.5-fold (P = .002) and 2.3-fold (P = .002), respectively, compared with incubation in 20% O-2. B16F10 mouse melanoma cells preincubated in 1% O-2 (versus 20% O-2) for 12 hours exhibited a twofold increase in resistance to doxorubicin (P < .001). The rapid acquisition of drug resistance after exposure to 1% O-2 could be mimicked by incubating the MDA-MB-231 cells for 12 hours with the NOS inhibitor NG-monomethyl-L-arginine (fivefold increase; P < .001). Conversely, replacement of NO activity by use of the NO-mimetic glyceryl trinitrate (GTN) and diethylenetriamine NO adduct produced statistically significant attenuations in the development of resistance of 59% (P < .001) and 40% (P < .001), respectively, in MDA-MB-231 cells. Treatment of B16F10 cells with GTN produced a 58% reduction in resistance (P < .001). MDA-MB-231 cells expressed all three isoforms of the NOS enzyme at levels that were not altered by exposure to hypoxia. Conclusions: NO mediates chemosensitivity in tumor cells, and hypoxia-induced drug resistance appears to result, in part, from downstream suppression of endogenous NO production. These results raise the possibility that administration of small doses of NO mimetics could be used as an adjuvant in chemotherapy.