Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy.
Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy.
Nanomedicine. 2020 Feb;24:102122. doi: 10.1016/j.nano.2019.102122. Epub 2019 Nov 6.
The flavoenzyme D-amino acid oxidase (DAAO) represents a potentially good option for cancer enzyme prodrug therapy as it produces HO using D-amino acids as substrates, compounds present at low concentration in vivo and that can be safely administered to regulate HO production. We optimized the cytotoxicity of the treatment by: i) using an efficient enzyme variant active at low O and D-alanine concentrations (mDAAO); ii) improving the stability and half-life of mDAAO and the enhanced permeability and retention effect by PEGylation; and iii) inhibiting the antioxidant cellular system by a heme oxygenase-1 inhibitor (ZnPP). A very low amount of PEG-mDAAO (10 mU, 50 ng of enzyme) induces cytotoxicity on various tumor cell lines. Notably, PEG-mDAAO seems well suited for in vivo evaluation as it shows the same cytotoxicity at air saturation (21%) and 2.5% O, a condition resembling the microenvironment found in the central part of tumors.
黄素酶 D-氨基酸氧化酶（DAAO）是癌症酶前药治疗的一个潜在的好选择，因为它使用 D-氨基酸作为底物产生 HO，这些化合物在体内浓度较低，可以安全地给药以调节 HO 的产生。我们通过以下方法优化了治疗的细胞毒性：i）使用在低 O 和 D-丙氨酸浓度下仍具有活性的高效酶变体（mDAAO）；ii）通过聚乙二醇化提高 mDAAO 的稳定性和半衰期，以及增强的通透性和保留效果；iii）通过血红素加氧酶-1 抑制剂（ZnPP）抑制抗氧化细胞系统。非常少量的 PEG-mDAAO（10 mU，50 ng 酶）对各种肿瘤细胞系产生细胞毒性。值得注意的是，PEG-mDAAO 似乎非常适合体内评估，因为它在空气饱和度为 21%和 O 为 2.5%的条件下表现出相同的细胞毒性，这种条件类似于肿瘤中心部分发现的微环境。
