Carcinogenesis Laboratory, National Institute of Cancerology, Mexico City, Mexico.
PLoS One. 2013 May 27;8(5):e64378. doi: 10.1371/journal.pone.0064378. Print 2013.
The use of chemopreventive natural compounds represents a promising strategy in the search for novel therapeutic agents in cancer. Resveratrol (3,4',5-trans-trihydroxystilbilene) is a dietary polyphenol found in fruits, vegetables and medicinal plants that exhibits chemopreventive and antitumor effects. In this study, we searched for modulated proteins with preventive or therapeutic potential in MCF-7 breast cancer cells exposed to resveratrol. Using two-dimensional electrophoresis we found significant changes (FC >2.0; p≤0.05) in the expression of 16 proteins in resveratrol-treated MCF-7 cells. Six down-regulated proteins were identified by tandem mass spectrometry (ESI-MS/MS) as heat shock protein 27 (HSP27), translationally-controlled tumor protein, peroxiredoxin-6, stress-induced-phosphoprotein-1, pyridoxine-5'-phosphate oxidase-1 and hypoxanthine-guanine phosphoribosyl transferase; whereas one up-regulated protein was identified as triosephosphate isomerase. Particularly, HSP27 overexpression has been associated to apoptosis inhibition and resistance of human cancer cells to therapy. Consistently, we demonstrated that resveratrol induces apoptosis in MCF-7 cells. Apoptosis was associated with a significant increase in mitochondrial permeability transition, cytochrome c release in cytoplasm, and caspases -3 and -9 independent cell death. Then, we evaluated the chemosensitization effect of increasing concentrations of resveratrol in combination with doxorubicin anti-neoplastic agent in vitro. We found that resveratrol effectively sensitize MCF-7 cells to cytotoxic therapy. Next, we evaluated the relevance of HSP27 targeted inhibition in therapy effectiveness. Results evidenced that HSP27 inhibition using RNA interference enhances the cytotoxicity of doxorubicin. In conclusion, our data indicate that resveratrol may improve the therapeutic effects of doxorubicin in part by cell death induction. We propose that potential modulation of HSP27 levels using natural alternative agents, as resveratrol, may be an effective adjuvant in breast cancer therapy.
使用化学预防天然化合物代表了在癌症治疗中寻找新型治疗剂的一种很有前途的策略。白藜芦醇（3,4',5-反式三羟基二苯乙烯）是一种在水果、蔬菜和药用植物中发现的膳食多酚，具有化学预防和抗肿瘤作用。在这项研究中，我们在暴露于白藜芦醇的 MCF-7 乳腺癌细胞中寻找具有预防或治疗潜力的调节蛋白。使用二维电泳，我们发现白藜芦醇处理的 MCF-7 细胞中 16 种蛋白质的表达发生了显著变化（FC>2.0;p≤0.05）。通过串联质谱（ESI-MS/MS）鉴定出 6 种下调蛋白为热休克蛋白 27（HSP27）、翻译控制肿瘤蛋白、过氧化物酶 6、应激诱导磷蛋白-1、吡哆醇 5'-磷酸氧化酶 1 和次黄嘌呤鸟嘌呤磷酸核糖基转移酶；而上调的一种蛋白为磷酸丙糖异构酶。特别是，HSP27 的过度表达与人类癌细胞凋亡抑制和对治疗的耐药性有关。一致地，我们证明白藜芦醇诱导 MCF-7 细胞凋亡。凋亡与线粒体通透性转换、细胞质中细胞色素 c 释放以及 caspase-3 和 caspase-9 依赖性细胞死亡的显著增加有关。然后，我们评估了体外增加白藜芦醇浓度与阿霉素抗肿瘤药物联合使用的化学增敏作用。我们发现白藜芦醇能有效地使 MCF-7 细胞对细胞毒性治疗敏感。接下来，我们评估了 HSP27 靶向抑制在治疗效果中的相关性。结果表明，使用 RNA 干扰抑制 HSP27 可增强阿霉素的细胞毒性。总之，我们的数据表明，白藜芦醇可能通过诱导细胞死亡来改善阿霉素的治疗效果。我们提出，使用天然替代物（如白藜芦醇）调节 HSP27 水平可能是乳腺癌治疗的有效辅助手段。
