Synthesis and antiviral activity of 2-substituted analogs of triciribine

Adjuvant Discovery via a High Throughput Screen using Human Primary Mononuclear Cells

Motivation

Vaccines are a key biomedical intervention to prevent the spread of infectious diseases, but their efficacy can be limited by insufficient immunogenicity and nonuniform reactogenic profiles. Adjuvants are molecules that potentiate vaccine responses by inducing innate immune activation. However, there are a limited number of adjuvants in approved vaccines, and current approaches for preclinical adjuvant discovery and development are inefficient. To enhance adjuvant identification, we developed a protocol based on in vitro screening of human primary leukocytes.

Summary

We describe a methodology utilizing high-throughput and high-content screening for novel adjuvant candidates that was used to screen a library of ~2,500 small molecules via a 384-well quantitative combined cytokine and flow cytometry immunoassay in primary human peripheral blood mononuclear cells (PBMCs) from 4 healthy adult study participants. Hits were identified based on their induction of soluble cytokine (TNF, IFNg and IL-10) secretion and PBMC maturation (CD 80/86, Ox40, and HLA-DR) in at least two of the four donors screened. From an initial set of 197 compounds identified using these biomarkers-an 8.6% hit rate-we downselected to five scaffolds that demonstrated robust efficacy and potency in vitro and evaluated the top hit, vinblastine sulfate, for adjuvanticity in vivo. Vinblastine sulfate significantly enhanced murine humoral responses to recombinant SARS-CoV-2 spike protein, including a four-fold enhancement of IgG titer production when compared to treatment with the spike antigen alone. Overall, we outline a methodology for discovering immunomodulators with adjuvant potential via high-throughput screening of PBMCs in vitro that yielded a lead compound with in vivo adjuvanticity.

Akt-independent effects of triciribine on ACE2 expression in human lung epithelial cells: Potential benefits in restricting SARS-CoV2 infection

The severe acute respiratory syndrome coronavirus 2 that causes coronavirus disease 2019 (COVID-19) binds to the angiotensin-converting enzyme 2 (ACE2) to gain cellular entry. Akt inhibitor triciribine (TCBN) has demonstrated promising results in promoting recovery from advanced-stage acute lung injury in preclinical studies. In the current study, we tested the direct effect of TCBN on ACE2 expression in human bronchial (H441) and lung alveolar (A549) epithelial cells. Treatment with TCBN resulted in the downregulation of both messenger RNA and protein levels of ACE2 in A549 cells. Since HMGB1 plays a vital role in the inflammatory response in COVID-19, and because hyperglycemia has been linked to increased COVID-19 infections, we determined if HMGB1 and hyperglycemia have any effect on ACE2 expression in lung epithelial cells and whether TCBN has any effect on reversing HMGB1- and hyperglycemia-induced ACE2 expression. We observed increased ACE2 expression with both HMGB1 and hyperglycemia treatment in A549 as well as H441 cells, which were blunted by TCBN treatment. Our findings from this study, combined with our previous reports on the potential benefits of TCBN in the treatment of acute lung injury, generate reasonable optimism on the potential utility of TCBN in the therapeutic management of patients with COVID-19.

Pyrroloaryls and pyrroloheteroaryls: Inhibitors of the HIV fusion/attachment, reverse transcriptase and integrase

Heterocyclic compounds execute a very important role in drug design and discovery. This article provides the basic milestones of the research for pyrroloaryl and pyrroloheteroaryl based components targeting HIV viral replication cycle. Anti-HIV activity is elaborated for several classes of pyrrolo-compounds as pyrrolopyridines, pyrrolopyrimidines, pyrrolopyridazines, pyrrolobenzodiazepinones, pyrrolobenzothiazepines, pyrrolobenzoxazepinones, pyrrolophenanthridines, pyrroloquinoxalines, pyrrolotriazines, pyrroloquinolines, pyrrolopyrazinones, pyrrolothiatriazines, arylthiopyrroles and pyrrolopyrazolones targeting two essential HIV enzymes, reverse transcriptase and integrase as well as attachment/fusion of HIV virons to the host CD-4 cell. Such attempts were resulted in a discovery of highly potent anti-HIV agents suitable for clinical trials, for example, BMS-378806, BMS-585248, BMS-626529, BMS-663068, BMS-488043 and BMS-663749, etc. as anti-HIV attachment agents, triciribine, QX432, BI-1 and BI-2 as HIV RT inhibitors which are in preclinical or clinical development. Mechanism of action of compounds presented in this article towards the suppression of HIV attachment/fusion as well as against the activities of HIV enzymes reverse transcriptase and integrase has been discussed. Relationships of new compounds' molecular framework and HIV viral target has been overviewed in order to facilitate further construction of promising anti-HIV agents in future drug discovery process.

Design, Synthesis and Antiviral Activity of Novel 4,5-Disubstituted 7-(β-d-Ribofuranosyl)pyrrolo[2,3-d][1,2,3]triazines and the Novel 3-Amino-5-methyl-1-(β-d-ribofuranosyl)- and 3-Amino-5-methyl-1-(2-deoxy-β-d-ribofuranosyl)-1,5-dihydro-1,4,5,6,7,8-hexaazaacenaphthylene as Analogues of Triciribine

The synthesis of several heterocyclic analogues of the biologically important nucleoside antibiotic toyocamycin and the tricyclic nucleoside triciribine (TCN) were prepared along with their 2'-deoxy counterparts. Coupling of 2-nitropyrrole-3,4-dicarboxamide (15) under a variety of conditions with alpha-chloro-2-deoxy-3,4-di-O-toluoyl-D-ribofuranose (16a) gave mixtures of the alpha and beta anomers. A coupling of 15 with 1-chloro-2,3,5-tri-O-benzoyl-D-ribofuranose (18) gave exclusively the beta anomer. Individually, the two pyrrole nucleosides were treated with Pd/C, H2 to reduce the nitro groups and cyclized with nitrous acid, and the corresponding 4-position was functionalized as a triazoyl derivative. Nucleophillic displacement was carried out with ammonia to give a mixture of 4-amino-1-(2,3,5-tri-O-benzoyl-beta-D-ribofuranosyl)pyrrolo[2,3-d][1,2,3]triazine-5-carbonitrile (26) and 2-amino-1-(2,3,5-tri-O-benzoyl-beta-D-ribofuranosyl)pyrrole-3,4-dicarbonitrile (27), the latter being formed via a retro-Diels-Alder reaction. The subsequent addition of hydrogen sulfide, water, methanol, hydroxylamine, cyanamide, hydrazine and methylhydrazine to the 5-cyano group was carried out to give the corresponding analogues. In the case of methyl hydrazine, subsequent treatment with NaOMe in methanol gave the title hexaazaacenaphthylenes. Biological evaluation of the compounds established that the pyrrole (17beta, 19-21) and most of the pyrrolotriazine (22, 24, 28, 32-34) nucleosides were inactive or weakly active against human cytomegalovirus (HCMV) and herpes simplex virus type 1 (HSV-1). In contrast 29 and 31 were active against one or both of these viruses but activity was poorly separated from cytotoxicity. In contrast, the 2-aza analogue of sangivamycin (30) was active against HCMV and HSV-1 but this apparent activity was most likely due to its high cytotoxicity. The tricyclic nucleoside 12, was active against its target virus, human immunodeficiency virus type 1 (HIV-1), but this activity was not well separated from cytotoxicity.