Synergistic effects of negative-charged nanoparticles assisted by ultrasound on the reversal multidrug resistance phenotype in breast cancer cells

• Published in: Ultrasonics sonochemistry 2017-01, Vol.34, p.448-457
• Main Authors: Wang, Dongxiao, Luo, Wanxian, Wen, Ge, Yang, Li, Hong, Shaofu, Zhang, Shiyu, Diao, Jianxin, Wang, Jianguo, Wei, Hongqin, Li, Yingjia, Wang, Ying
• Format: Article
• Language: English
• Subjects: Breast Neoplasms - pathology; Cell Proliferation - drug effects; Cell-Penetrating Peptides - chemistry; Cell-Penetrating Peptides - metabolism; Cell-Penetrating Peptides - pharmacology; Drug Resistance, Neoplasm; Endocytosis; Gene Expression Regulation, Neoplastic - drug effects; Humans; MCF-7 Cells; Multidrug resistance; Nanoparticles; Negative-charged nanoparticles; Phenotype; Synergistic effects; Ultrasonic Waves; Ultrasound
• ISSN: 1350-4177; 1873-2828
• DOI: 10.1016/j.ultsonch.2016.06.012

•A negative-charged dual-ligand NP is synthesized but fails to overcome MDR.•Cells treated with US prior to NP improves cytotoxity and eliminates damage from US.•The strategy triggers endosomal escape and affects related proteins in MDR reversal. We have fabricated a negative-charged nanoparticle (Heparin-Folate-Tat-Taxol NP, H-F-Tat-T NP) with dual ligands, tumor targeting ligand folate and cell-penetrating peptide Tat, to deliver taxol presenting great anticancer activity for sensitive cancer cells, while it fails to overcome multidrug resistance (MDR) in MCF-7/T cells (taxol-resistant breast cancer cells). Ultrasound (US) can increase the sensitivity of positive-charged NPs thereby making it possible to reverse MDR through inducing NPs’ drug release. However, compared with the negative-charged NPs, positive-charged NPs may cause higher toxic effect. Hence, the combination of negative-charged NPs and US may be an efficient strategy for overcoming MDR. The conventional procedure to treat with NPs followed by US exposure possibly destruct multifunctional NPs resulting in its bioactivity inhibition. Herein, we have further improved the operating approach to eliminate US mechanical damage and keep the integrity of negative-charged NPs: cells are exposed to US with microbubbles (MBs) prior to the treatment of H-F-Tat-T NPs. Superior to the conventional method, US sonoporation affects the physiological property of cancer cells while preventing direct promotion of drug release from NPs. The results of the present study displayed that US in condition (1MHz, 10% duty cycle, duration of 80s, US intensity of 0.6W/cm2 and volume ratio of medium to MBs 20:1) combined with H-F-T-Tat-T NPs can achieve optimal reversal MDR effect in MCF-7/T cells. Mechanism study further disclosed that the individual effect of US was responsible for the enhancement of cell membrane permeability, inhibition of cell proliferation rate and down-regulation of MDR-related genes and proteins. Simultaneously, US sonoporation on resistant cancer cells indirectly increased the accumulation of NPs by inducing endosomal escape of negative-charged NPs. Taken together, the overcoming MDR ability for the combined strategy was achieved by the synergistic effect from individual function of NPs, physiological changes of resistant cancer cells and behavior changes of NPs caused by US.