ingenol-dibenzoate and ingenol

Despite the durable viral suppression afforded by antiretroviral therapy, HIV-1 eradication will require strategies to target latently infected cells that persist in infected individuals. Protein kinase C (PKC) activation is a promising strategy to reactivate latent proviruses and allow for subsequent recognition and clearance of infected cells by the immune system. Ingenol derivatives are PKC agonists that induce latency reversal but also lead to T cell activation and the release of pro-inflammatory cytokines, which would be undesirable in vivo. In this work, we sought to identify compounds that would suppress pro-inflammatory cytokine production in the context of PKC activation.. We performed an in vitro screen to identify compounds that could dampen pro-inflammatory cytokine release associated with T cell activation, using IL-6 as a model cytokine. We then tested the ability of the most promising screening hit, the FDA-approved Janus Kinase (JAK) inhibitor ruxolitinib, to diminish release of multiple cytokines and its effect on latency reversal using cells from HIV-1-positive, aviremic participants.. We demonstrate that co-administration of ruxolitinib with ingenol-3,20-dibenzoate significantly reduces pro-inflammatory cytokine release without impairing latency reversal ex vivo.. The combination of ingenol compounds and JAK inhibition represents a novel strategy for HIV-1 eradication.

Topics: Anti-HIV Agents; CD4-Positive T-Lymphocytes; Cytokines; Diterpenes; Drug Evaluation, Preclinical; High-Throughput Screening Assays; HIV Infections; HIV-1; Humans; Interleukin-6; Janus Kinases; Lymphocyte Activation; Nitriles; Protein Kinase C; Pyrazoles; Pyrimidines; Virus Activation; Virus Latency

Ingenol derivatives have received constant and multidisciplinary attention on account of their pleiotropic pattern of biological activity. This includes activation of protein kinase C (PKC), tumour-promotion, anticancer, and anti-HIV properties, and the possibility of dissecting co-cancerogenic and clinically useful activities has been demonstrated. Certain ingenol esters show powerful anticancer activity, and a structure-activity relationship model to discriminate between their apoptotic and non-apoptotic properties has been developed.. The polyhydroxylated southern region of ingenol was selectively modified, using the anticancer and PKC activator ingenol 3,20-dibenzoate (IDB) as a lead compound. The evaluation of IDB analogues in apoptosis assays showed strict structure-activity relationships, benzoylation of the 20-hydroxyl being required to trigger apoptosis through a pathway involving caspase-3 and occurring at the specific cell cycle checkpoint that controls the S-M phase transition. Conversely, a study on the activation of the PKC-dependent transcription factors AP-1 and NF-kappaB by IDB analogues showed significant molecular flexibility, including tolerance to changes at the 3- and 20-hydroxyls. IDB-induced apoptosis was independent of activation of PKC, since it was not affected by treatment with the non-isoform-selective PKC inhibitor GF 109230X0.. Remarkable deviations from the tumour-promotion pharmacophore were observed for both the apoptotic and the PKC-activating properties of IDB analogues, showing that ingenol is a viable template to selectively target crucial pathways involved in tumour promotion and development. Since the apoptotic and the PKC-activating properties of ingenoids are mediated by different pathways and governed by distinct structure-activity relationships, it is possible to dissect them by suitable chemical modification. In this context, the esterification pattern of the 5- and 20-hydroxyls is critical.

Topics: Apoptosis; Caspase 3; Caspase Inhibitors; Caspases; Cell Cycle; Diterpenes; DNA; DNA Fragmentation; Electrophoretic Mobility Shift Assay; Esters; HeLa Cells; Humans; In Situ Nick-End Labeling; Jurkat Cells; Luciferases; NF-kappa B; Protein Kinase C; S Phase; Signal Transduction; Structure-Activity Relationship; Transcription Factor AP-1