4-(2-(5-6-7-8-tetrahydro-5-5-8-8-tetramethyl-2-naphthalenyl)-1-propenyl)benzoic-acid 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

There is a major clinical need for new therapies for the treatment of chronic itch. Many of the molecular components involved in itch neurotransmission are known, including the neuropeptide NPPB, a transmitter required for normal itch responses to multiple pruritogens in mice. Here, we investigated the potential for a novel strategy for the treatment of itch that involves the inhibition of the NPPB receptor NPR1 (natriuretic peptide receptor 1). Because there are no available effective human NPR1 (hNPR1) antagonists, we performed a high-throughput cell-based screen and identified 15 small-molecule hNPR1 inhibitors. Using in vitro assays, we demonstrated that these compounds specifically inhibit hNPR1 and murine NPR1 (mNPR1). In vivo, NPR1 antagonism attenuated behavioral responses to both acute itch- and chronic itch-challenged mice. Together, our results suggest that inhibiting NPR1 might be an effective strategy for treating acute and chronic itch.

Topics: Animals; Behavior, Animal; Cell-Free System; Dermatitis, Contact; Disease Models, Animal; Ganglia, Spinal; Humans; Mice, Inbred C57BL; Mice, Knockout; Neurons; Pruritus; Receptors, Atrial Natriuretic Factor; Reproducibility of Results; Signal Transduction; Small Molecule Libraries

Retinoids have been used in the clinic for the prevention and treatment of human cancers. They regulate several cellular processes including growth, differentiation, and apoptosis. Previously, we demonstrated that a pan-agonist retinoid 9-cis retinoic acid was able to suppress mammary tumorigenesis in the C3(1)-SV40 T-antigen (Tag) transgenic mouse model. However, significant toxicity was seen with this naturally occurring retinoid. We hypothesized that the cancer preventive effects of retinoids could be dissected from the toxic effects by using receptor-selective retinoids. In this study, we used TTNPB, an retinoic acid receptor-selective retinoid, and LGD1069, an retinoid X receptor-selective retinoid, to preferentially activate retinoic acid receptors and retinoid X receptors. In vitro, both compounds were able to inhibit the growth of T47D breast cancer cells. We then determined whether these retinoids prevented mammary tumorigenesis. C3(1)-SV40 Tag mice were treated daily by gastric gavage with vehicle, two different doses of TTNPB (0.3 or 3.0 microg/kg), or two different doses of LGD1069 (10 or 100 mg/kg). Mice were treated from approximately 6-8 weeks to 7-8 months of age. Tumor size and number were measured twice each week, and toxicities were recorded daily. Our data show that LGD1069 suppresses mammary tumorigenesis in C3(1)-SV40 Tag transgenic mice with no observable toxicity, whereas TTNPB had a modest chemopreventive effect, yet was very toxic. Median time to tumor development was 129 days in vehicle-treated mice versus 156 days in mice treated with 100 mg/kg LGD1069 (P = 0.05). In addition, tumor multiplicity was reduced by approximately 50% in mice treated with LGD1069 (2.9 for vehicle, 2.4 for 10 mg/kg LGD1069, and 1.4 for 100 mg/kg, P < or = 0.03). TTNPB-treated mice showed a delayed median time to tumor development (131 days for vehicle versus 154 days for 3.0 microg/kg TTNPB; P < or = 0.05), but no changes were seen in tumor multiplicity. However, toxicity (skin erythema, hair loss) was seen in all of the mice treated with TTNPB. These data demonstrate that receptor-selective retinoids suppress mammary tumorigenesis in transgenic mice and that preventive effects of retinoids can be separated from their toxicity, demonstrating that receptor-selective retinoids are promising agents for the prevention of breast cancer.

Topics: Animals; Anticarcinogenic Agents; Antineoplastic Agents; Benzoates; Bexarotene; Biomarkers, Tumor; Breast Neoplasms; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Growth Inhibitors; Histones; Mammary Neoplasms, Experimental; Mice; Mice, Transgenic; Receptors, Retinoic Acid; Retinoid X Receptors; Retinoids; Sensitivity and Specificity; Tetrahydronaphthalenes; Time Factors; Transcription Factors; Treatment Outcome

Retinoids are natural and synthetic analogues of the hormone retinoic acid. Systemic retinoid agonist therapy is usually associated with toxic side effects, such as mucocutaneous toxicity, which may be alleviated by the use of topical retinoid antagonists. We report the synthesis and biological activity of a new series of potent, RAR-specific antagonists substituted with phenylcyclohexene and phenylcyclohexadiene groups.

Topics: Animals; Benzoates; Cyclohexanes; Dermatitis, Irritant; Disease Models, Animal; Mice; Receptors, Retinoic Acid; Retinoids

Retinoids constitute a very promising class of agents for the chemoprevention or treatment of breast cancer. These retinoids exert their biological activity through two distinct classes of retinoic acid (RA) receptors (R), the RAR isotypes (alpha, beta, and gamma) and the three RXR isotypes (alpha, beta, and gamma) and their numerous isoforms which bind as RXR/RAR heterodimers to the polymorphic cis-acting response elements of RA target genes. With respect to these numerous receptor sub-types, the retinoid-induced effects at the biological level include marked modifications with respect to both cell proliferation and cell death (apoptosis), and also in the induction of differentiation processes. The present study aims to characterize the effect which four retinoids (TTNPB, 9-cis-RA, LGD 1069, 4-HPR) with distinct RAR/RXR binding properties induced on various in vitro and in vivo mouse and human breast cancer models. The experiments with the retinoids were carried out in comparison with the anti-estrogen tamoxifen and the anti-progestagen RU-486 compounds. The results show that the 6 compounds under study were markedly more efficient in terms of growth inhibition in the human T-47D cell line when maintained under anchorage-independent culture conditions than when maintained under anchorage-dependent ones. While RU-486 exhibited a weak statistically significant (p < 0.05) influence on the growth of the T-47D stem cells, tamoxifen had a marked inhibitory influence on the growth of these cells. Of the four retinoids, 4-HPR was the least effective since the lowest doses tested (1 and 0.1 nM) exhibited no statistically (p > 0.05) significant influence on the growth of the stem cells. The most efficient retinoid was TTNPB. It was only at the highest dose (10 microM) that tamoxifen and RU-486 showed a weak inhibitory influence on the growth of the T-47D non-stem cells while all 4 retinoids exerted a significant inhibitory influence on the growth of these non-stem cells, with 4-HPR being the most efficient (P < 0.001) at the highest dose, but ineffective (P > 0.05) at the lowest. Tamoxifen and TTNPB were tested in vivo on hormone-sensitive (HS) and hormone-insensitive (HI) strains of the MXT murine mammary carcinoma. While TTNPB appeared to be equally efficient in terms of growth inhibition in both MXT-HS and MXT-HI models, tamoxifen had only a marginal inhibitory influence on the growth of the MXT-HI strain but did inhibit growth in the case of the MXT-HS one. TT

Topics: Alitretinoin; Animals; Anticarcinogenic Agents; Apoptosis; Benzoates; Bexarotene; Breast Neoplasms; Cell Division; Disease Models, Animal; Female; Fenretinide; Hormone Antagonists; Humans; Mammary Neoplasms, Animal; Mice; Mice, Inbred C57BL; Mifepristone; Retinoids; Tamoxifen; Tetrahydronaphthalenes; Tretinoin; Tumor Cells, Cultured