Chen Fengqian, Zhang Jinming, Wang Lu, Wang Yitao, Chen Meiwan
State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao 999078, China.
Nanoscale. 2015 Oct 14;7(38):15763-79. doi: 10.1039/c5nr04612b. Epub 2015 Sep 10.
The insufficient cellular uptake of nanocarriers and their slow drug release have become major obstacles for achieving satisfactory anticancer outcomes in nano-medicine therapy. Because of the slightly acidic extracellular environment (pHe≈ 6.5) and a higher glutathione (GSH) concentration (approximately 10 mM) in tumor tissue/cells, we firstly designed a novel d-α-tocopheryl polyethylene glycol 1000-poly(β-amino ester) block copolymer containing disulfide linkages (TPSS). TPSS nanoparticles (NPs) with pH- and redox-sensitive behaviors were developed for on-demand delivery of docetaxel (DTX) in hepatocellular carcinoma. DTX/TPSS NPs exhibited sensitive surface charge reversal from -47.6 ± 2.5 mV to +22.5 ± 3.2 mV when the pH decreased from 7.4 to 6.5, to simulate the pHe. Meanwhile, anabatic drug release of DTX/TPSS NPs was observed in PBS buffer (pH 6.5, 10 mM GSH). Due to the synergism between the pHe-triggered charge reversal and the redox-triggered drug release, enhanced drug uptake and anticancer efficacy were observed in HepG2 and SMMC 7721 cells treated with DTX/TPSS NPs. The positively charged NPs exhibited a stronger inhibitory effect on cell proliferation, promoted cell cycle arrest in the G2/M phase, and increased the rate of apoptosis. More importantly, based on the higher tumor accumulation of TPSS vehicles in vivo, a significant suppression of tumor growth, but without side-effects, was observed when DTX/TPSS NPs were injected intravenously into HepG2 xenograft tumor-bearing mice. Collectively, these results demonstrate that the newly developed dual-functional TPSS copolymer may be utilized as a drug delivery system for anticancer therapy.
纳米载体的细胞摄取不足及其缓慢的药物释放已成为纳米医学治疗中实现令人满意的抗癌效果的主要障碍。由于肿瘤组织/细胞中细胞外环境呈弱酸性(pHe≈6.5)且谷胱甘肽(GSH)浓度较高(约10 mM),我们首先设计了一种新型的含二硫键的d-α-生育酚聚乙二醇1000-聚(β-氨基酯)嵌段共聚物(TPSS)。开发了具有pH和氧化还原敏感性的TPSS纳米颗粒(NPs),用于在肝细胞癌中按需递送多西他赛(DTX)。当pH从7.4降至6.5以模拟肿瘤细胞外pH值时,DTX/TPSS NPs表现出敏感的表面电荷反转,从-47.6±2.5 mV变为+22.5±3.2 mV。同时,在PBS缓冲液(pH 6.5,10 mM GSH)中观察到DTX/TPSS NPs的药物释放增加。由于pH触发的电荷反转和氧化还原触发的药物释放之间的协同作用,在用DTX/TPSS NPs处理的HepG2和SMMC 7721细胞中观察到药物摄取增强和抗癌效果增强。带正电荷的NPs对细胞增殖表现出更强的抑制作用,促进细胞周期停滞在G2/M期,并增加凋亡率。更重要的是,基于TPSS载体在体内较高的肿瘤蓄积,当将DTX/TPSS NPs静脉注射到荷HepG2异种移植瘤小鼠体内时,观察到肿瘤生长受到显著抑制且无副作用。总体而言,这些结果表明新开发的双功能TPSS共聚物可作为抗癌治疗的药物递送系统。