Tao Wenhui, Zhao Dongyang, Sun Mengchi, Li Meng, Zhang Xiangyu, He Zhonggui, Sun Yinghua, Sun Jin
Department of Pharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, No. 103, Wenhua Road, Shenyang, 110016, China.
Key Laboratory of Structure-Based Drug Design and Discovery, Shenyang Pharmaceutical University, Ministry of Education, No. 103, Wenhua Road, Shenyang, 110016, China.
Drug Deliv Transl Res. 2017 Apr;7(2):304-311. doi: 10.1007/s13346-016-0356-1.
A primary focus of this research was to explore the activation process and mechanism of decitabine (5-aza-2'-deoxycytidine, DAC) prodrug. Recently, it has been reported that biphenyl hydrolase-like protein (BPHL) can play an important role in the activation of some amino acid nucleoside prodrugs with a general preference for hydrophobic amino acids and 5'-esters. Therefore, we put forward a bold hypothesis that this novel enzyme may be primarily responsible for the activation process of DAC prodrug as well. 5'-O-L-valyl-decitabine (L-val-DAC) was synthesized before and can be transported across biological membranes by the oligopeptide transporter (PEPT1), granting it much greater utility in vivo. In this report, L-val-DAC was found to be a good substrate of BPHL protein (K 0.59 mM; k /K 553.69 mM s). After intestinal absorption, L-val-DAC was rapidly and almost completely hydrolyzed to DAC and L-valine. The catalysis was mainly mediated by the BPHL hydrolase and resulted in the intestinal first-pass effect of L-val-DAC after oral administration in Sprague-Dawley rats with cannulated jugular and portal veins. The structural insights using computational molecular docking showed that BPHL had a unique binding mode for L-val-DAC. As a fundamental basis, the simulation was employed to explain the catalytic mechanism in molecular level. In conclusion, BPHL was at least one of the primary candidate enzymes for L-val-DAC prodrug activation. This promising double-targeted prodrug approach have more advantages than the traditional targeted designs due to its higher transport and more predictable activation, thereby leading to a favorable property for oral delivery.
本研究的一个主要重点是探索地西他滨（5-氮杂-2'-脱氧胞苷，DAC）前药的激活过程和机制。最近，有报道称，联苯水解酶样蛋白（BPHL）在某些氨基酸核苷前药的激活中可发挥重要作用，通常对疏水氨基酸和5'-酯具有偏好性。因此，我们大胆提出一个假设，即这种新型酶可能也是DAC前药激活过程的主要负责者。5'-O-L-缬氨酰-地西他滨（L-val-DAC）之前已合成，并且可以通过寡肽转运体（PEPT1）跨生物膜转运，这使其在体内具有更大的实用性。在本报告中，发现L-val-DAC是BPHL蛋白的良好底物（K 0.59 mM；k /K 553.69 mM·s）。经肠道吸收后，L-val-DAC迅速且几乎完全水解为DAC和L-缬氨酸。该催化作用主要由BPHL水解酶介导，导致在颈静脉和门静脉插管的Sprague-Dawley大鼠口服给药后L-val-DAC出现肠道首过效应。使用计算分子对接的结构见解表明，BPHL对L-val-DAC具有独特的结合模式。作为基础，该模拟用于在分子水平上解释催化机制。总之，BPHL至少是L-val-DAC前药激活的主要候选酶之一。这种有前景的双靶点前药方法由于其更高的转运率和更可预测的激活，比传统的靶向设计具有更多优势，从而具有良好的口服给药特性。
