pf-00299804 and Disease-Models--Animal

Topics: Afatinib; Amino Acid Sequence; Animals; Cell Line; Disease Models, Animal; ErbB Receptors; Exons; Humans; Lung Neoplasms; Mice; Mutagenesis, Insertional; Mutation; Neoplasm Staging; Protein Kinase Inhibitors; Quinazolinones

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

Despite overexpression of the ErbB (EGFR/HER2/ErbB3/ErbB4) family in castration-resistant prostate cancer (CRPC), some inhibitors of this family, including the dual EGFR/HER2 inhibitor lapatinib, failed in Phase II clinical trials. Hence, we investigated mechanisms of lapatinib resistance to determine whether alternate ErbB inhibitors can succeed.. The CWR22 human tumour xenograft and its CRPC subline 22Rv1 and sera from lapatinib-treated CRPC patients from a previously reported Phase II trial were used to study lapatinib resistance. Mechanistic studies were conducted in LNCaP, C4-2 and 22Rv1 cell lines.. Lapatinib increased intratumoral HER2 protein, which encouraged resistance to this treatment in mouse models. Sera from CRPC patients following lapatinib treatment demonstrated increased HER2 levels. Investigation of the mechanism of lapatinib-induced HER2 increase revealed that lapatinib promotes HER2 protein stability, leading to membrane localisation, EGFR/HER2 heterodimerisation and signalling, elevating cell viability. Knockdown of HER2 and ErbB3, but not EGFR, sensitised CRPC cells to lapatinib. At equimolar concentrations, the recently FDA-approved pan-ErbB inhibitor dacomitinib decreased HER2 protein stability, prevented ErbB membrane localisation (despite continued membrane integrity) and EGFR/HER2 heterodimerisation, thereby decreasing downstream signalling and increasing apoptosis.. Targeting the EGFR axis using the irreversible pan-ErbB inhibitor dacomitinib is a viable therapeutic option for CRPC.

Topics: Animals; Cell Line, Tumor; Disease Models, Animal; ErbB Receptors; Humans; Lapatinib; Male; Mice; Mice, Inbred BALB C; Prostatic Neoplasms, Castration-Resistant; Protein Multimerization; Quinazolinones; Receptor, ErbB-2

ATP-binding cassette subfamily G member 2 (ABCG2), a member of the ABC transporter superfamily proteins, mediates multidrug resistance (MDR) by transporting substrate anticancer drugs out of cancer cells and decreasing their intracellular accumulation. MDR is a major hurdle to successful chemotherapy. A logical approach to overcome MDR is to inhibit the transporter. However, no safe and effective MDR inhibitor has been approved in the clinic.. The MTT assay was used to evaluate cell cytotoxicity and MDR reversal effect. Drug efflux and intracellular drug accumulation were measured by flow cytometry. The H460/MX20 cell xenograft model was established to evaluate the enhancement of anticancer efficacy of topotecan by dacomitinib in vivo. To ascertain the interaction of dacomitinib with the substrate binding sites of ABCG2, the competition of dacomitinib for photolabeling of ABCG2 with [. These results suggest that dacomitinib reverses ABCG2-mediated MDR by inhibiting ABCG2 efflux function and increasing intracellular accumulation of anticancer agents. Our findings advocate further clinical investigation of combinations of dacomitinib and conventional chemotherapy in cancer patients with ABCG2-overexpressing MDR tumors.

Topics: Animals; Antineoplastic Agents; ATP Binding Cassette Transporter, Subfamily G, Member 2; Cell Line, Tumor; Cell Membrane; Disease Models, Animal; Drug Resistance, Neoplasm; Extracellular Signal-Regulated MAP Kinases; Gene Expression; Humans; Inhibitory Concentration 50; Mice; Models, Biological; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Quinazolinones; Topotecan; Xenograft Model Antitumor Assays

Dacomitinib-an irreversible pan-ErbB tyrosine kinase inhibitor (TKI)-causes diarrhoea in 75% of patients. Dacomitinib-induced diarrhoea has not previously been investigated and the mechanisms remain poorly understood. The present study aimed to develop an in-vitro and in-vivo model of dacomitinib-induced diarrhoea to investigate underlying mechanisms. T84 cells were treated with 1-4 μM dacomitinib and resistance and viability were measured using transepithelial electrical resistance (TEER) and XTT assays. Rats were treated with 7.5 mg/kg dacomitinib daily via oral gavage for 7 or 21 days (n = 6/group). Weights, and diarrhoea incidence were recorded daily. Rats were administered FITC-dextran 2 hr before cull, and serum levels of FITC-dextran were measured and serum biochemistry analysis was conducted. Detailed histopathological analysis was conducted throughout the gastrointestinal tract. Gastrointestinal expression of ErbB1, ErbB2 and ErbB4 was analysed using RT-PCR. The ileum and the colon were analysed using multiplex for expression of various cytokines. T84 cells treated with dacomitinib showed no alteration in TEER or cell viability. Rats treated with dacomitinib developed severe diarrhoea, and had significantly lower weight gain. Further, dacomitinib treatment led to severe histopathological injury localised to the ileum. This damage coincided with increased levels of MCP1 in the ileum, and preferential expression of ErbB1 in this region compared to all other regions. This study showed dacomitinib induces severe ileal damage accompanied by increased MCP1 expression, and gastrointestinal permeability in rats. The histological changes were most pronounced in the ileum, which was also the region with the highest relative expression of ErbB1.

Topics: Animals; Cell Line, Tumor; Cell Survival; Chemokine CCL2; Colorectal Neoplasms; Diarrhea; Disease Models, Animal; ErbB Receptors; Gastrointestinal Tract; Gene Expression; Humans; Ileum; Immunohistochemistry; Male; Permeability; Quinazolinones; Radioimmunoprecipitation Assay; Rats, Wistar; Reverse Transcriptase Polymerase Chain Reaction