■曲妥珠单抗,针对HER2的治疗性单克隆抗体常规用于治疗HER2阳性乳腺癌,且应答率良好.然而,由于不良副作用,在临床实践中引起了人们的关注。克服这些限制的一种方法是将曲妥珠单抗封装在纳米颗粒中以改善细胞毒性活性,增加细胞内药物浓度,逃避免疫系统并避免药物在体内的全身性降解。
■使用双重乳液方法将曲妥珠单抗封装到聚(乳酸-共-乙醇酸)纳米颗粒中,有效的生物相容性和生物降解性。这些纳米载体,以下简称TZP,以尺寸为特征,同质性,zeta电位并测试其稳定性和药物释放动力学。最后,在HER2阳性SKBR3乳腺癌细胞系上体外评估TZPs的细胞毒性,并与游离曲妥珠单抗进行比较.
■TZP是稳定的,尺寸均匀,具有降低的zeta电位。它们显示出更高的包封效率和载药量,延长曲妥珠单抗释放动力学,保留其物理化学性质和功能。在所分析的细胞系中,TZP比相似剂量的游离曲妥珠单抗显示更强的细胞毒性和增加的细胞凋亡。共聚焦显微镜和流式细胞术评估TZP和曲妥珠单抗细胞摄取,而Westernblot评估下游信号,整体HER2含量和脱落。
■TZP通过双重作用模式比游离曲妥珠单抗发挥更强大的作用:TZP通过内吞机制被细胞吸收,并在细胞内释放药物更长的时间。此外,保留在细胞外空间的TZP释放与同源受体结合并削弱下游信号传导的曲妥珠单抗.这是游离曲妥珠单抗使用的唯一方式。值得注意的是,半剂量的TZPs与最高剂量的游离药物一样有效,这支持了它们可能用于体内药物递送。
UNASSIGNED: Trastuzumab, a therapeutic monoclonal antibody directed against HER2, is routinely used to treat HER2-positive breast cancer with a good response rate. However, concerns have arisen in the clinical practice due to adverse side effects. One way to overcome these limitations is to encapsulate trastuzumab in nanoparticles to improve cytotoxic activity, increase intracellular drug concentrations, escape the immune system and avoid systemic degradation of the drug in vivo.
UNASSIGNED: A double emulsion method was used to encapsulate trastuzumab into poly(lactic-co-glycolic) nanoparticles, effective for their biocompatibility and biodegradability. These nanocarriers, hereafter referred to as TZPs, were characterised in terms of size, homogeneity, zeta potential and tested for their stability and drug release kinetics. Finally, the TZPs cytotoxicity was assessed in vitro on the HER2 positive SKBR3 breast cancer cell line and compared to free trastuzumab.
UNASSIGNED: The TZPs were stable, homogeneous in size, with a reduced zeta potential. They showed higher encapsulation efficiency and drug loading, a prolonged trastuzumab release kinetics that retained its physicochemical properties and functionality. TZPs showed a stronger cytotoxicity and increased apoptosis than similar doses of free trastuzumab in the cell line analysed. Confocal microscopy and flow cytometry assessed TZPs and trastuzumab cellular uptake while Western blot evaluated downstream signalling, overall HER2 content and shedding.
UNASSIGNED: TZPs exert more robust effects than free trastuzumab via a dual mode of action: TZPs are taken up by cells through an endocytosis mechanism and release the drug intracellularly for longer time. Additionally, the TZPs that remain in the extracellular space release trastuzumab which binds to the cognate receptor and impairs downstream signalling. This is the sole modality used by free trastuzumab. Remarkably, half dose of TZPs is as efficacious as the highest dose of free drug supporting their possible use for drug delivery in vivo.