Quinolinonyl Non-Diketo Acid Derivatives as Inhibitors of HIV‑1 Ribonuclease H and Polymerase Functions of Reverse Transcriptase

Novel anti-HIV agents
are still needed to overcome resistance issues,
in particular inhibitors acting against novel viral targets. The ribonuclease
H (RNase H) function of the reverse transcriptase (RT) represents
a validated and promising target, and no inhibitor has reached the
clinical pipeline yet. Here, we present rationally designed non-diketo
acid selective RNase H inhibitors (RHIs) based on the quinolinone
scaffold starting from former dual integrase (IN)/RNase H quinolinonyl
diketo acids. Several derivatives were synthesized and tested against
RNase H and viral replication and found active at micromolar concentrations.
Docking studies within the RNase H catalytic site, coupled with site-directed
mutagenesis, and Mg2+ titration experiments demonstrated
that our compounds coordinate the Mg2+ cofactor and interact
with amino acids of the RNase H domain that are highly conserved among
naïve and treatment-experienced patients. In general, the new
inhibitors influenced also the polymerase activity of RT but were
selective against RNase H vs the IN enzyme.

仍需开发新型抗HIV（anti-HIV）药物以克服耐药性难题，尤其是针对新型病毒靶点的抑制剂。逆转录酶（Reverse Transcriptase, RT）的核糖核酸酶H（Ribonuclease H, RNase H）功能是一个经过验证且极具前景的药物靶点，目前尚无相关抑制剂进入临床研发管线。本研究基于先前开发的双靶点整合酶（Integrase, IN）/RNase H喹啉酮基二酮酸类化合物，合理设计得到了以喹啉酮骨架为母核的非二酮酸类选择性RNase H抑制剂（RNase H Inhibitors, RHIs）。我们合成了多款衍生物，并针对RNase H活性与病毒复制能力开展活性评价，结果显示其在微摩尔浓度范围内即可展现出显著抑制活性。通过对RNase H催化位点开展的分子对接研究、结合定点诱变实验与镁离子（Mg²+）滴定实验，证实本研究的目标化合物可与Mg²+辅因子配位结合，并与RNase H结构域的氨基酸残基产生相互作用；该结构域在初治患者与经治患者中均高度保守。整体而言，这类新型抑制剂同样会对RT的聚合酶活性产生一定影响，但相较于整合酶，其对RNase H展现出更优的选择性。