Novel Synergistic Anti-Enteroviral Drug Combinations

Background: Enterovirus infections affect people around the world, causing a range of illnesses, from mild fevers to severe, potentially fatal conditions. There are no approved treatments for enterovirus infections. Methods: We have tested our library of broad-spectrum antiviral agents (BSAs) against echovirus 1 (EV1) in human adenocarcinoma alveolar basal epithelial A549 cells. We also tested combinations of the most active compounds against EV1 in A549 and human immortalized retinal pigment epithelium RPE cells. Results: We confirmed anti-enteroviral activities of pleconaril, rupintrivir, cycloheximide, vemurafenib, remdesivir, emetine, and anisomycin and identified novel synergistic rupintrivir–vemurafenib, vemurafenib–pleconaril and rupintrivir–pleconaril combinations against EV1 infection. Conclusions: Because rupintrivir, vemurafenib, and pleconaril require lower concentrations to inhibit enterovirus replication in vitro when combined, their cocktails may have fewer side effects in vivo and, therefore, should be further explored in preclinical and clinical trials against EV1 and other enterovirus infections.

Assessment of cellular and molecular changes in the rat brain after gamma radiation and radioprotection by anisomycin

The objective of the study was to describe cellular and molecular markers of radioprotection by anisomycin, focusing on the changes in rat brain tissue. Two-month-old Wistar rats were exposed to a 60Co radiation source at a dose of 6 Gy, with or without radioprotection with anisomycin (150 mg/kg) administered subcutaneously 30 min before or 3 or 6 h after irradiation. Survivors were analyzed 30 days after treatment. Astroglial and microglial responses were investigated based on the expression of glial markers assessed with immunohistochemistry, and quantitative changes in brain biomolecules were investigated by Raman microspectroscopy. In addition, blood plasma levels of pro-inflammatory (interleukin 6 and tumor necrosis factor α) and anti-inflammatory (interleukin 10) cytokines were assessed. We found that application of anisomycin either before or after irradiation significantly decreased the expression of the microglial marker Iba-1. We also found an increased intensity of Raman spectral bands related to nucleic acids, as well as an increased level of cytokines when anisomycin was applied after irradiation. This suggests that the radioprotective effects of anisomycin are by decreasing Iba-1 expression and stabilizing genetic material by increasing the level of nucleic acids.

[Effect of anisomycin on allogeneic skin transplantation in mice]

AIM

To investigate the effect of anisomycin on the reactivity of lymphocytes and the rejection in the skin transplantation in mice.

METHODS

The reactivity of T cells in unilateral or bilateral mixed lymphocyte reaction was detected by MTT assay. The skins from C57BL/6 mice were transplanted to BALB/c mice and the survival period of the grafts was assessed. The recipients were divided into three groups (physiological saline group, cyclosporin A group and anisomycin group). They were injected with physiological saline (0.1 mL), cyclosporin A (20 mg/kg) and anisomycin (12.5 mg/kg) separately once a day for 3 days before the operation and 7 days after the operation.

RESULTS

With the optimal dose of 10.0 microg/L, anisomycin inhibited the reactivity of lymphocyte cells in both unilateral and bilateral mixed lymphocyte reactions. The survival period of the grafts from anisomycin group was longer than that from cyclosporin A group and physiological saline group.

CONCLUSION

Anisomycin can inhibit the reaction of lymphocytes and prolong the survival period of the grafts in skin transplantation effectively. It could be used as a new way for transplantation rejection treatment.

A Chemical Screen Identifies Anisomycin as an Anoikis Sensitizer That Functions by Decreasing FLIP Protein Synthesis

Malignant epithelial cells with metastatic potential resist apoptosis that normally occurs upon loss of anchorage from the extracellular matrix, a process termed "anoikis." Resistance to anoikis enables malignant cells to survive in an anchorage-independent manner, which leads to the formation of distant metastases. To understand the regulation of anoikis, we designed, automated, and conducted a high-throughput chemical screen for anoikis sensitizers. PPC-1 anoikis-resistant prostate cancer cells were seeded in hydrogel-coated ultralow binding plates for suspension conditions and standard tissue culture plates to promote adhesion. After seeding, cells were treated with aliquots from a library of previously characterized small molecules, and viability was assessed using the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt, assay. From this chemical screen, we identified anisomycin that induced apoptosis in suspension conditions, but was not toxic to these cells grown under adherent conditions. Anisomycin sensitized cells to anoikis by decreasing levels of the caspase-8 inhibitor FLIP and subsequently activating the death receptor pathway of caspase activation. Although anisomycin activated c-Jun-NH(2)-kinase and p38, these kinases were not functionally important for the effect of anisomycin on anoikis and FLIP. Rather, anisomycin decreased FLIP and sensitized cells to anoikis by inhibiting its protein synthesis. Finally, we showed that anisomycin decreased distal tumor formation in a mouse model of prostate cancer metastases. Thus, a novel chemical screen identified anisomycin as an anoikis sensitizer that acts by decreasing FLIP protein synthesis. Our results suggest that FLIP is a suppressor of anoikis and inhibiting FLIP protein synthesis may be a useful antimetastatic strategy.

Suppression of fever in rabbits by a protein synthesis inhibitor, anisomycin

1. The protein synthesis inhibitor, anisomycin, was given into the cerebral ventricles of rabbits as a priming dose followed by a continuous infusion. Doses of 100, 200 and 300 microgram followed by infusions at 100, 200 and 300 microgram/hr inhibited the incorporation of [14C] leucine into hypothalamic protein by over 90%. 2. Injection and infusion of anisomycin (300 microgram) suppressed the febrile response to leucocyte (endogenous) pyrogen given into the ventricles (I.C.V.) or I.V. 3. Dialysis experiments showed that anisomycin did not combine irreversibly with leucocyte pyrogen. 4. Anisomycin did not interfere with thermoregulation in a cold environment. 5. It is concluded that pyrogenesis may involve a step which is dependent on synthesis of hypothalamic protein with a rapid turnover.