Department of Pharmaceutical and Pharmacological Sciences, University of Padova, via Marzolo 5, 35131, Italy.
Department of Chemistry, University of Padova, via Marzolo 1, 35131, Italy.
J Control Release. 2021 Dec 10;340:318-330. doi: 10.1016/j.jconrel.2021.11.006. Epub 2021 Nov 6.
Tyrosine kinase inhibitors (TKIs) represent one of the most advanced class of therapeutics for cancer treatment. Most of them are also cytochrome P450 (CYP) inhibitors and/or substrates thereof. Accordingly, their efficacy and/or toxicity can be affected by CYP-mediated metabolism and by metabolism-derived drug-drug interactions. In order to enhance the therapeutic performance of these drugs, we developed a prodrug (Pro962) of our TKI TK962 specifically designed for liposome loading and pH-controlled release in the tumor. A cholesterol moiety was linked to TK962 through pH-sensitive hydrazone bond for anchoring to the liposome phospholipid bilayer to prevent leakage of the prodrug from the nanocarrier. Bioactivity studies performed on isolated target kinases showed that the prodrug maintains only partial activity against them and the release of TK962 is required. Biopharmaceutical studies carried out with prodrug loaded liposomes showed that the prodrug was firmly associated with the vesicles and the drug release was prevented under blood-mimicking conditions. Conversely, conventional liposome loaded with TK962 readily released the drug. Flow cytometric studies showed that liposomes efficiently provided for intracellular prodrug delivery. The use of the hydrazone linker yielded a pH-controlled drug release, which resulted in about 50% drug release at pH 4 and 5 in 2 h. Prodrug, prodrug loaded liposomes and active lead compound have been tested against cancer cell lines in either 2D or 3D models. The liposome formulation showed higher cytotoxicity than the unformulated lead TK962 in both 2D and 3D models. The stability of prodrug, prodrug loaded liposomes and active lead compound in human serum and against human, mouse, and rat microsomes was also assessed, demonstrating that liposome formulations impair the metabolic reactions and protect the loaded compounds from catabolism. The results suggest that the liposomal formulation of pH releasable TKI prodrugs is a promising strategy to improve the metabolic stability, intracellular cancer cell delivery and release, and in turn the efficacy of this class of anticancer drugs.
酪氨酸激酶抑制剂 (TKIs) 是癌症治疗中最先进的治疗药物之一。它们中的大多数也是细胞色素 P450 (CYP) 抑制剂和/或其底物。因此，它们的疗效和/或毒性可能受到 CYP 介导的代谢和代谢衍生的药物相互作用的影响。为了提高这些药物的治疗性能，我们专门设计了一种 TKI TK962 的前药 (Pro962)，用于脂质体负载和肿瘤中 pH 控制的释放。胆固醇部分通过 pH 敏感的腙键与 TK962 连接，用于锚定在脂质体磷脂双层上，以防止前药从纳米载体中漏出。对分离的靶激酶进行的生物活性研究表明，前药对它们仅保持部分活性，需要释放 TK962。用载有前药的脂质体进行的生物制药研究表明，前药与囊泡牢固结合，并且在模拟血液的条件下阻止药物释放。相反，载有 TK962 的常规脂质体容易释放药物。流式细胞术研究表明，脂质体能够有效地提供细胞内前药递送。使用腙键连接得到 pH 控制的药物释放，在 2 小时内 pH 值为 4 和 5 时约有 50%的药物释放。前药、载有前药的脂质体和活性先导化合物已在 2D 或 3D 模型中针对癌细胞系进行了测试。在 2D 和 3D 模型中，脂质体配方比未成型的先导 TK962 表现出更高的细胞毒性。还评估了前药、载有前药的脂质体和活性先导化合物在人血清中和针对人、小鼠和大鼠微粒体中的稳定性，表明脂质体配方会损害代谢反应并保护负载化合物免受分解代谢。结果表明，pH 可释放 TKI 前药的脂质体配方是一种很有前途的策略，可以提高代谢稳定性、细胞内癌细胞递送和释放，从而提高这类抗癌药物的疗效。
