Abstract：
The human DNA repair enzyme AlkB homologue-2 (ALKBH2) repairs methyl adducts from genomic DNA and is overexpressed in several cancers. However, there are no known inhibitors available for this crucial DNA repair enzyme. The aim of this study was to examine whether the first-generation HIV protease inhibitors having strong anti-cancer activity can be repurposed as inhibitors of ALKBH2. We selected four such inhibitors and performed in vitro binding analysis against ALKBH2 based on alterations of its intrinsic tryptophan fluorescence and differential scanning fluorimetry. The effect of these HIV protease inhibitors on the DNA repair activity of ALKBH2 was also evaluated. Interestingly, we observed that one of the inhibitors, ritonavir, could inhibit ALKBH2-mediated DNA repair significantly via competitive inhibition and sensitized cancer cells to alkylating agent methylmethane sulfonate (MMS). This work may provide new insights into the possibilities of utilizing HIV protease inhibitor ritonavir as a DNA repair antagonist.
摘要：
人类DNA修复酶AlkB同源物2（ALKBH2）从基因组DNA修复甲基加合物，并在几种癌症中过表达。然而,没有已知的抑制剂可用于这种关键的DNA修复酶。这项研究的目的是研究具有强抗癌活性的第一代HIV蛋白酶抑制剂是否可以用作ALKBH2的抑制剂。我们选择了四种此类抑制剂，并基于其固有色氨酸荧光和差示扫描荧光测定法的改变对ALKBH2进行了体外结合分析。还评估了这些HIV蛋白酶抑制剂对ALKBH2的DNA修复活性的影响。有趣的是,我们观察到其中一种抑制剂，利托那韦,可以通过竞争性抑制和使癌细胞对烷化剂甲磺酸甲酯（MMS）敏感来显着抑制ALKBH2介导的DNA修复。这项工作可能为利用HIV蛋白酶抑制剂利托那韦作为DNA修复拮抗剂的可能性提供新的见解。
