Quercetin-loaded magnetic nanoparticles: a promising tool for antitumor treatment in human breast cancer cells

Quercetin (QUE) is a phytoestrogen with known antitumor properties; however, its hydrophobic nature and low bioavailability limit its efficacy as an anticancer drug. To address this, we explored loading QUE onto a non-toxic nanocarrier. This study focused on the biological activity of magnetic iron oxide nanoparticles coated with polyethylene glycol (MAG@PEG) loaded with QUE (MAG@PEG@QUE) in MCF-7 cells. The MAG@PEG nanosystem was synthesised using a hydrothermal method, and QUE was incorporated by adding an alcoholic solution of QUE to an aqueous dispersion of MAG@PEG. QUE incorporation was confirmed qualitatively by FTIR spectroscopy and quantitatively through UV–visible spectroscopy. Cytotoxicity studies showed that MAG@PEG@QUE, at a concentration equivalent to the half-maximal inhibitory concentration (IC₅₀) of free QUE, significantly reduced cell proliferation and viability while increasing apoptosis. MCF-7 cells treated with MAG@PEG@QUE also displayed actin cytoskeleton alterations typical of apoptotic cells. Transmission electron microscopy revealed clusters of magnetic nanoparticles within cellular vesicles. Targeted delivery of these nanoparticles was achieved using a static magnetic field, leading to high intracellular accumulation and selective cell death in targeted areas, without affecting adjacent cells. In conclusion, MAG@PEG@QUE shows comparable antitumor effects to free QUE and has the potential to enhance QUE’s bioavailability and targeted delivery for breast cancer treatment.

槲皮素（Quercetin, QUE）是一类具有明确抗肿瘤活性的植物雌激素，但其疏水性与低生物利用度限制了其作为抗癌药物的应用效果。为解决这一问题，本研究探索了将QUE负载至无毒纳米载体的方案。本研究聚焦于聚乙二醇包覆磁性氧化铁纳米粒（MAG@PEG）负载QUE后形成的复合物（MAG@PEG@QUE）在MCF-7细胞中的生物学活性。本研究采用水热法合成MAG@PEG纳米递送系统，并通过将QUE的乙醇溶液加入MAG@PEG的水分散液中完成QUE的负载。采用傅里叶变换红外光谱（FTIR）对QUE的负载进行了定性验证，通过紫外-可见分光光度法完成了定量表征。细胞毒性实验结果显示，当MAG@PEG@QUE的浓度等同于游离QUE的半数抑制浓度（IC₅₀）时，其可显著降低细胞增殖与活力，同时诱导细胞凋亡。经MAG@PEG@QUE处理的MCF-7细胞还呈现出凋亡细胞典型的肌动蛋白细胞骨架形态改变。透射电子显微镜观察到细胞囊泡内存在磁性纳米粒聚集现象。通过施加静磁场可实现该纳米粒的靶向递送，使靶区域实现较高的细胞内蓄积并引发选择性细胞死亡，且未对邻近细胞造成影响。综上，MAG@PEG@QUE展现出与游离QUE相当的抗肿瘤效果，且有望提升QUE的生物利用度，为乳腺癌的靶向治疗提供潜在应用价值。