AIDS Immunopathology Department, National Centre of Microbiology, Instituto de Salud Carlos III. Ctra. Pozuelo Km. 2. Majadahonda, 28224 Madrid, Spain.
AIDS Immunopathology Department, National Centre of Microbiology, Instituto de Salud Carlos III. Ctra. Pozuelo Km. 2. Majadahonda, 28224 Madrid, Spain; Pharmacology Department, Pharmacy Faculty, Universidad Complutense de Madrid, Pz. Ramón Y Cajal s/n, 28040 Madrid, Spain.
Biochem Pharmacol. 2020 Jul;177:113937. doi: 10.1016/j.bcp.2020.113937. Epub 2020 Mar 26.
Latent HIV reservoirs are the main obstacle to eradicate HIV infection. One strategy proposes to eliminate these viral reservoirs by pharmacologically reactivating the latently infected T cells. We show here that a 4-deoxyphorbol ester derivative isolated from Euphorbia amygdaloides ssp. semiperfoliata, 4β-dPE A, reactivates HIV-1 from latency and could potentially contribute to decrease the viral reservoir. 4β-dPE A shows two effects in the HIV replication cycle, infection inhibition and HIV transactivation, similarly to other phorboids PKC agonists such PMA and prostratin and to other diterpene esters such SJ23B. Our data suggest 4β-dPE A is non-tumorigenic, unlike the related compound PMA. As the compounds are highly similar, the lack of tumorigenicity by 4β-dPE A could be due to the lack of a long side lipophilic chain that is present in PMA. 4β-dPE activates HIV transcription at nanomolar concentrations, lower than the concentration needed by other latency reversing agents (LRAs) such as prostratin and similar to bryostatin. PKCθ/MEK activation is required for the transcriptional activity, and thus, anti-latency activity of 4β-dPE A. However, CD4, CXCR4 and CCR5 receptors down-regulation effect seems to be independent of PCK/MEK, suggesting the existence of at least two different targets for 4β-dPE A. Furthermore, NF-κb transcription factor is involved in 4β-dPE HIV reactivation, as previously shown for other PKCs agonists. We also studied the effects of 4β-dPE A in combination with other LRAs. When 4β-dPE A was combined with another PKC agonists such as prostratin an antagonic effect was achieved, while, when combined with an HDAC inhibitor such as vorinostat, a strong synergistic effect was obtained. Interestingly, the latency reversing effect of the combination was synergistically diminishing the EC value but also increasing the efficacy showed by the drugs alone. In addition, combinations of 4β-dPE A with antiretroviral drugs as CCR5 antagonist, NRTIs, NNRTIs and PIs, showed a consistent synergistic effect, suggesting that the combination would not interefer with antiretroviral therapy (ART). Finally, 4β-dPE A induced latent HIV reactivation in CD4 + T cells of infected patients under ART at similar levels than the tumorigenic phorbol derivative PMA, showing a clear reactivation effect. In summary, we describe here the mechanism of action of a new potent deoxyphorbol derivative as a latency reversing agent candidate to decrease the size of HIV reservoirs.
潜伏的 HIV 储库是根除 HIV 感染的主要障碍。一种策略是通过药理学激活潜伏感染的 T 细胞来消除这些病毒储库。我们在这里表明，一种从 Euphorbia amygdaloides ssp. semiperfoliata 中分离出的 4-脱氧佛波醇酯衍生物 4β-dPE A 可使 HIV-1 从潜伏期重新激活，并可能有助于减少病毒储库。4β-dPE A 在 HIV 复制周期中具有两种作用，即感染抑制和 HIV 转激活，与其他 PKC 激动剂（如 PMA 和 prostratin）和其他二萜酯（如 SJ23B）相似。我们的数据表明，4β-dPE A 是非致瘤的，与相关化合物 PMA 不同。由于这些化合物非常相似，因此 4β-dPE A 缺乏致瘤性可能是由于其缺乏 PMA 中存在的长侧脂溶性链。4β-dPE A 在纳摩尔浓度下激活 HIV 转录，低于其他潜伏逆转剂（LRAs）如 prostratin 和 bryostatin 的浓度。PKCθ/MEK 激活是 4β-dPE A 转录活性和抗潜伏活性所必需的。然而，CD4、CXCR4 和 CCR5 受体下调效应似乎独立于 PKC/MEK，表明 4β-dPE A 至少有两个不同的靶点。此外，NF-κb 转录因子参与 4β-dPE A 的 HIV 重新激活，如先前对其他 PKC 激动剂的研究所示。我们还研究了 4β-dPE A 与其他 LRA 联合使用的效果。当 4β-dPE A 与另一种 PKC 激动剂（如 prostratin）联合使用时，会产生拮抗作用，而当与 HDAC 抑制剂（如 vorinostat）联合使用时，会产生强烈的协同作用。有趣的是，组合的潜伏逆转作用协同降低了 EC 值，同时也增加了药物单独使用的疗效。此外，4β-dPE A 与 CCR5 拮抗剂、NRTIs、NNRTIs 和 PIs 等抗逆转录病毒药物的组合显示出一致的协同作用，表明该组合不会干扰抗逆转录病毒治疗（ART）。最后，4β-dPE A 在接受 ART 的感染患者的 CD4+T 细胞中诱导潜伏的 HIV 重新激活，其水平与致瘤性佛波醇衍生物 PMA 相似，显示出明显的重新激活作用。总之，我们在这里描述了一种新型强效脱氧佛波醇衍生物作为潜伏逆转剂候选物的作用机制，可减少 HIV 储库的大小。
