bms-911543 and Disease-Models--Animal

When Zika virus emerged as a public health emergency there were no drugs or vaccines approved for its prevention or treatment. We used a high-throughput screen for Zika virus protease inhibitors to identify several inhibitors of Zika virus infection. We expressed the NS2B-NS3 Zika virus protease and conducted a biochemical screen for small-molecule inhibitors. A quantitative structure-activity relationship model was employed to virtually screen ∼138,000 compounds, which increased the identification of active compounds, while decreasing screening time and resources. Candidate inhibitors were validated in several viral infection assays. Small molecules with favorable clinical profiles, especially the five-lipoxygenase-activating protein inhibitor, MK-591, inhibited the Zika virus protease and infection in neural stem cells. Members of the tetracycline family of antibiotics were more potent inhibitors of Zika virus infection than the protease, suggesting they may have multiple mechanisms of action. The most potent tetracycline, methacycline, reduced the amount of Zika virus present in the brain and the severity of Zika virus-induced motor deficits in an immunocompetent mouse model. As Food and Drug Administration-approved drugs, the tetracyclines could be quickly translated to the clinic. The compounds identified through our screening paradigm have the potential to be used as prophylactics for patients traveling to endemic regions or for the treatment of the neurological complications of Zika virus infection.

Topics: Animals; Antiviral Agents; Artificial Intelligence; Chlorocebus aethiops; Disease Models, Animal; Drug Evaluation, Preclinical; High-Throughput Screening Assays; Immunocompetence; Inhibitory Concentration 50; Methacycline; Mice, Inbred C57BL; Protease Inhibitors; Quantitative Structure-Activity Relationship; Small Molecule Libraries; Vero Cells; Zika Virus; Zika Virus Infection

Activation of Janus kinase 2 (JAK2), frequently as a result of the JAK2(V617F) mutation, is a characteristic feature of the classical myeloproliferative neoplasms (MPNs) polycythemia vera, essential thrombocythemia, and myelofibrosis, and it is thought to be responsible for the constitutional symptoms associated with these diseases. BMS-911543 is a JAK2-selective inhibitor that induces apoptosis in JAK2-dependent cell lines and inhibits the growth of CD34(+) progenitor cells from patients with JAK2(V617F)-positive MPN. To explore the clinical potential of this inhibitor, we tested BMS-911543 in a murine retroviral transduction-transplantation model of JAK2(V617F) MPN. Treatment was initiated at two dose levels (3 mg/kg and 10 mg/kg) when the hematocrit exceeded 70%. Following the first week, white blood cell counts were reduced to normal in the high-dose group and were maintained well below the levels in vehicle-treated mice throughout the study. However, BMS-911543 had no effect on red blood cell parameters. After 42 days of treatment, the proportion of JAK2(V617F)-positive cells in hematopoietic tissues was identical or slightly increased compared with controls. Plasma concentrations of interleukin 6, interleukin 15, and tumor necrosis factor α were elevated in MPN mice and reduced in the high-dose treatment group, whereas other cytokines were unchanged. Inhibitor activity after dosing was confirmed in a cell culture assay using the plasma of dosed mice and phosphorylated signal transducer and activator of transcription 5 flow cytometry. Collectively, these results show that BMS-911543 has limited activity in this murine model of JAK2(V617F)-driven MPN and suggest that targeting JAK2 alone may be insufficient to achieve effective disease control.

Topics: Animals; Antineoplastic Agents; Bone Marrow; Cytokines; Disease Models, Animal; Drug Screening Assays, Antitumor; Female; Heterocyclic Compounds, 3-Ring; Humans; Janus Kinase 2; Mice; Mice, Inbred BALB C; Molecular Targeted Therapy; Mutation, Missense; Myeloproliferative Disorders; Neoplasm Proteins; Point Mutation; Protein Kinase Inhibitors; Radiation Chimera; Spleen

The Jak/STAT pathway is activated in human pancreatic ductal adenocarcinoma (PDAC) and cooperates with mutant Kras to drive initiation and progression of PDAC in murine models. We hypothesized that the small-molecule Jak2 inhibitor (BMS-911543) would elicit anti-tumor activity against PDAC and decrease immune suppressive features of the disease. We used an aggressive genetically engineered PDAC model with mutant KrasG12D, tp53R270H, and Brca1 alleles (KPC-Brca1 mice). Mice with confirmed tumor burden were treated orally with vehicle or 30 mg/kg BMS-911543 daily for 14 days. Histologic analysis of pancreata from treated mice revealed fewer foci of adenocarcinoma and significantly decreased Ki67+ cells versus controls. In vivo administration of BMS-911543 significantly reduced pSTAT5 and FoxP3 positive cells within the pancreas, but did not alter STAT3 phosphorylation. Continuous dosing of KPC-Brca1 mice with BMS-911543 resulted in a median survival of 108 days, as compared to a median survival of 87 days in vehicle treated animals, a 23% increase (p = 0.055). In vitro experiments demonstrated that PDAC cell lines were poorly sensitive to BMS-911543, requiring high micromolar concentrations to achieve targeted inhibition of Jak/STAT signaling. Similarly, BMS-911543 had little in vitro effect on the viability of both murine and human PDAC-derived stellate cell lines. However, BMS-911543 potently inhibited phosphorylation of pSTAT3 and pSTAT5 at low micromolar doses in human PBMC and reduced in vitro differentiation of Foxp3+ T regulatory cells. These results indicate that single agent Jak2i deserves further study in preclinical models of PDAC and has distinct inhibitory effects on STAT5 mediated signaling.

Topics: Animals; Antineoplastic Agents; Carcinoma, Pancreatic Ductal; Cell Survival; Disease Models, Animal; Dose-Response Relationship, Drug; Forkhead Transcription Factors; Genes, BRCA1; Genes, p53; Genes, ras; Genetic Predisposition to Disease; Heterocyclic Compounds, 3-Ring; Janus Kinase 2; Lymphocytes, Tumor-Infiltrating; Mice, Transgenic; Molecular Targeted Therapy; Mutation; Pancreatic Neoplasms; Phenotype; Phosphorylation; Protein Kinase Inhibitors; Signal Transduction; STAT5 Transcription Factor; T-Lymphocytes, Regulatory; Time Factors; Tumor Burden