Development of an enzyme-linked immunosorbent assay for Keap1-Nrf2 interaction inhibitors identification.

Development of Keap1-Nrf2 interaction inhibitors is a promising strategy for the discovery of therapeutic agents against oxidative stress-mediated diseases. Two motifs of Nrf2, ETGE and DLG motif, are responsible for Keap1-Nrf2 binding. Previously, ETGE peptide or ETGE-derived peptide-based approaches were used to detect Keap1-Nrf2 interaction; however, these approaches are not able to monitor Keap1-DLG motif binding. We first report here a novel Enzyme-linked Immunosorbent Assay (ELISA) approach to detect the protein-protein interaction of full length Keap1 and Nrf2. In our assay, the test compounds can target either ETGE or DLG binding site, therefore facilitating the exploration of diverse Keap1-Nrf2 inhibitors. Three FDA-approved drugs, zafirlukast, dutasteride and ketoconazole, were found to inhibit the Keap1-Nrf2 interaction with IC50 of 5.87, 2.81 and 1.67 µM, respectively. Additionally, these three drugs also activated Nrf2 pathway in neuroblasts and lipopolysaccharide (LPS)-challenged mice. The results presented here indicate that the ELISA approach has the capacity to identify Keap1-Nrf2 inhibitors.

Design, synthesis, and biological activity of a novel series of benzofuran derivatives against oestrogen receptor-dependent breast cancer cell lines.

A docking study of a novel series of benzofuran derivatives with ERα was conducted. In this study, we report the synthesis of a novel series of benzofuran derivatives and evaluation of their anticancer activity in vitro against MCF-7 human breast cancer cells, as well as their potential toxicity to ER-independent MDA-MB-231 breast cancer cells, human renal epithelial HEK-293 cells, and human immortal keratinocytes (HaCaT cells) by using the MTT colorimetric assay. The screening results indicated that the target compounds exhibited anti-breast cancer activity. The target compound 2-benzoyl-3-methyl-6-[2-(morpholin-4-yl)ethoxy]benzofuran hydrochloride (4e) exhibited excellent activity against anti-oestrogen receptor-dependent breast cancer cells and low toxicity. The preliminary structure-activity relationships of the target benzofuran derivatives have been summarised. In conclusion, the novel benzofuran scaffold may be a promising lead for the development of potential oestrogen receptor inhibitors.

Discovery of a Novel HIV-1 Integrase/p75 Interacting Inhibitor by Docking Screening, Biochemical Assay, and in Vitro Studies.

Protein-protein interaction between lens epithelium-derived growth factor (LEDGF/p75) and HIV-1 integrase becomes an attractive target for anti-HIV drug development. The blockade of this interaction by small molecules could potentially inhibit HIV-1 replication. These small molecules are termed as LEDGINs; and several newly identified LEDGINs have been reported to significantly reduce HIV-1 replication. Through this project, we have finished the docking screening of the Maybridge database against the p75 binding site of HIV-1 integrase using both DOCK and Autodock Vina software. Finally, we have successfully identified a novel scaffold LEDGINs inhibitor DW-D-5. Its antiviral activities and anticatalytic activity of HIV-1 integrase are similar to other LEDGINs under development. We demonstrated that the combination of DW-D-5 and FDA approved anti-HIV drugs resulted in additive inhibitory effects on HIV-1 replication, indicating that DW-D-5 could be an important component of combination pills for clinic use in HIV treatment.

Herbalog: A tool for target-based identification of herbal drug efficacy through molecular docking.

BACKGROUND: Traditionally, molecular docking is primarily employed to screen pure compounds; the top-ranking chemicals are subsequently selected for experimental validation. Unlike synthetic chemicals, most natural products are commercially unavailable. The isolation and purification of each natural product is extremely time-consuming, which has restricted the screening of lead compounds from natural products. PURPOSE: We developed a protocol, Herbalog, to facilitate the identification of bioactive phytochemicals through molecular docking. METHODS: We wrote a script using Python and Autodock Vina for docking; ligand displacement and adipolysis assays were used to determine the anti-fatty acid binding protein (FABP) 4 activity of bioactive extracts. An ultraperformance liquid chromatography quadrupole time-of-flight mass spectrometry system was applied for identifying major peaks of bioactive extracts. RESULTS: Herbalog, a natural product database, contains 5,112 phytochemicals from 197 common herbs and a script that counts the number of hits from docking in each herb and calculates the hit rate of herbs. Herbalog prioritizes herbs according to their hit rates, and top-ranking herb candidates contain a large repertoire of hits. We used Herbalog as a screening tool and identified labdane diterpenoids from Andrographis paniculata as leading candidates of FABP4 inhibitors. CONCLUSION: Herbalog facilitates the discovery of herbs that possess the highest number of inhibitors or activators against target proteins, which reduces the sample preparation time for preliminary validation.

Pimozide, a novel fatty acid binding protein 4 inhibitor, promotes adipogenesis of 3T3-L1 cells by activating PPARγ.

Pimozide is a conventional antipsychotic of the diphenylbutylpiperidine class that has been clinically used for over 30 years. The obvious side effect of this drug is weight gain. However, the mechanism of pimozide-induced weight gain is still unknown. In the present study, we identified pimozide as a novel fatty acid binding protein 4 (FABP4) inhibitor using molecular docking simulation as well as biochemical characterizations. BMS309403, a well-known FABP4 inhibitor, elevated the basal protein levels of PPARγ, therefore stimulating adipogenesis in adipocytes. The present study showed that the inhibitory effect of pimozide on FABP4 promoted adipocyte differentiation with the potency proportional to their propensities for weight gain. These effects in adipogenesis by pimozide may help to explain the weight gain that is frequently observed in patients treated with pimozide.

Discovery of FDA-approved drugs as inhibitors of fatty acid binding protein 4 using molecular docking screening.

We first identified fluorescein, ketazolam, antrafenine, darifenacin, fosaprepitant, paliperidone, risperidone, pimozide, trovafloxacin, and levofloxacin as inhibitors of fatty acid binding protein 4 using molecular docking screening from FDA-approved drugs. Subsequently, the biochemical characterizations showed that levofloxacin directly inhibited FABP4 activity in both the in vitro ligand displacement assay and cell-based function assay. Furthermore, levofloxacin did not induce adipogenesis in adipocytes, which is the major adverse effect of FABP4 inhibitors.

Silibinin, a novel chemokine receptor type 4 antagonist, inhibits chemokine ligand 12-induced migration in breast cancer cells.

PURPOSE: C-X-C chemokine receptor type 4 (CXCR4) signaling has been demonstrated to be involved in cancer invasion and migration; therefore, CXCR4 antagonist can serve as an anti-cancer drug by preventing tumor metastasis. This study aimed to identify the CXCR4 antagonists that could reduce and/or inhibit tumor metastasis from natural products. METHODS AND RESULTS: According to the molecular docking screening, we reported here silibinin as a novel CXCR4 antagonist. Biochemical characterization showed that silibinin blocked chemokine ligand 12 (CXCL12)-induced CXCR4 internalization by competitive binding to CXCR4, therefore inhibiting downstream intracellular signaling. In human breast cancer cells MDA-MB-231, which expresses high levels of CXCR4, inhibition of CXCL12-induced chemomigration can be found under silibinin treatment. Overexpression of CXCL12 sensitized MDA-MB-231 cells to the inhibition of silibinin, which was abolished by CXCR4 knockdown. The inhibition of silibinin was also observed in MCF-7/CXCR4 cells rather than MCF-7 cells that express low level of CXCR4. CONCLUSIONS: Our work demonstrated that silibinin is a novel CXCR4 antagonist that may have potential therapeutic use for prevention of tumor metastasis.