Structural modification of C2-substituents on 1,4-bis(arylsulfonamido)benzene or naphthalene-N,N'-diacetic acid derivatives as potent inhibitors of the Keap1-Nrf2 protein-protein interaction.

The Keap1-Nrf2-ARE signaling pathway is an attractive therapeutic target for the prevention and treatment of oxidative stress-associated diseases by activating the cellular expression of cytoprotective enzymes and proteins. Small molecule inhibitors can directly disrupt the Keap1-Nrf2 protein-protein interaction (PPI), resulting in elevated levels of Nrf2 protein and subsequent stimulation of related antioxidant responses. Previously, we found that 1,4-bis(arylsulfonamido)benzene or naphthalene-N,N'-diacetic acid derivatives with an ether type C2-substituent on the benzene or naphthalene core exhibited potent inhibitory activities with IC50's in the submicromolar or nanomolar range. We here describe a more detailed structure-activity relationship study around the C2 substituents containing various polar linkers shedding new insight on their binding interactions with the Keap1 Kelch domain. The key observation from our findings is that the substituents at the C2-position of the benzene or naphthalene scaffold impact their inhibitory potencies in biochemical assays as well as activities in cell culture. The biochemical FP and TR-FRET assays revealed that the naphthalene derivatives 17b and 18 with an additional carboxylate at the C2 were the most active inhibitors against Keap1-Nrf2 PPI. In the cell-based assay, the two compounds were shown to be potent Nrf2 activators of the transcription of the Nrf2-dependent genes, such as HMOX2, GSTM3, and NQO1.

Design, synthesis, and antitumor screening of new thiazole, thiazolopyrimidine, and thiazolotriazine derivatives as potent inhibitors of VEGFR-2.

New thiazole, thiazolopyrimidine, and thiazolotriazine derivatives 3-12 and 14a-f were synthesized. The newly synthesized analogs were tested for in vitro antitumor activity against HepG2, HCT-116, MCF-7, HeP-2, and Hela cancer cells. Results indicated that compound 5 displayed the highest potency toward the tested cancer cells. Compound 11b possessed enhanced effectiveness over MCF-7, HepG2, HCT-116, and Hela cancer cells. In addition, compounds 4 and 6 showed promising activity toward HCT-116, MCF-7, and Hela cancer cells and eminent activity against HepG2 and HeP-2 cells. Moreover, compounds 3-6 and 11b were tested for their capability to inhibit vascular endothelial growth factor receptor-2 (VEGFR-2) activity. The obtained results showed that compound 5 displayed significant inhibitory activity against VEGFR-2 (half-maximal inhibitory concentration [IC50 ] = 0.044 µM) comparable to sunitinib (IC50 = 0.100 µM). Also, the synthesized compounds 3-6 and 11b were subjected to in vitro cytotoxicity tests over WI38 and WISH normal cells. It was found that the five tested compounds displayed significantly lower cytotoxicity than doxorubicin toward normal cell lines. Cell cycle analysis proved that compound 5 induces cell cycle arrest in the S phase for HCT-116 and Hela cancer cell lines and in the G2/M phase for the MCF-7 cancer cell line. Moreover, compound 5 induced cancer cell death through apoptosis accompanied by a high ratio of BAX/BCL-2 in the screened cancer cells. Furthermore, docking results revealed that compound 5 showed the essential interaction bonds with VEGFR-2, which agreed with in vitro enzyme assay results. In silico studies showed that most of the analyzed compounds complied with the requirements of good oral bioavailability with minimal toxicity threats in humans.

Optimization of the C2 substituents on the 1,4-bis(arylsulfonamido)naphthalene-N,N'-diacetic acid scaffold for better inhibition of Keap1-Nrf2 protein-protein interaction.

Direct inhibition of the protein-protein interaction (PPI) between Kelch-like ECH-associated protein 1 (Keap1) and nuclear factor erythroid 2-related factor 2 (Nrf2) reduces the ubiquitination and subsequent degradation of Nrf2, leading to Nrf2 accumulation in the cytosol and the nuclear translocation of Nrf2. Once inside the nucleus, Nrf2 binds to and activates the expression of antioxidant response element (ARE) genes involved in redox homeostasis and detoxification. Herein, we report a series of 1,4-bis(arylsulfonamido)naphthalene-N,N'-diacetic acid analogs with varying C2 substituents to explore the structure-activity relationships at this position of the central naphthalene core. The Keap1-binding activities were first screened with a fluorescence polarization (FP) assay followed by further evaluation of the more potent compounds using a more sensitive time-resolved fluorescence energy transfer (TR-FRET) assay. It was found that compound 24a with C2-phthalimidopropyl group was the most potent in this series showing an IC50 of 2.5 nM in the TR-FRET assay with a Ki value in the subnanomolar range. Our docking study indicated that the C2-phthalimidopropyl group in compound 24a provided an extra hydrogen bonding interaction with the key residue Arg415 that may be responsible for the observed boost in binding affinity. In addition, compounds 12b, 15, and 24a were shown to activate the Nrf2 signaling pathway in NCM460D cells resulting in elevated mRNA levels of GSTM3, HMOX1 and NQO1 by 2.4-11.7 fold at 100 µM as compared to the vehicle control.

Inhibitors of Keap1-Nrf2 protein-protein interaction reduce estrogen responsive gene expression and oxidative stress in estrogen receptor-positive breast cancer.

Estrogen contributes to the development of breast cancer through estrogen receptor (ER) signaling and by generating genotoxic metabolites that cause oxidative DNA damage. To protect against oxidative stress, cells activate nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream cytoprotective genes that initiate antioxidant responses and detoxify xenobiotics. Nrf2 activation occurs by inhibiting the protein-protein interaction (PPI) between Nrf2 and its inhibitor Keap1, which otherwise targets Nrf2 for ubiquitination and destruction. In this study, we examined a series of novel direct inhibitors of Keap1-Nrf2 PPI in their role in promoting the availability of Nrf2 for antioxidant activity and attenuating estrogen-mediated responses in breast cancer. ER-positive human breast cancer cells MCF-7 were treated with 17ß-estradiol (E2) in the presence or absence of selected Keap1-Nrf2 PPI inhibitors. Keap1-Nrf2 PPI inhibitors suppressed the mRNA and protein levels of estrogen responsive genes induced by E2 exposure, such as PGR. Keap1-Nrf2 PPI inhibitors caused significant activation of Nrf2 target genes. E2 decreased the mRNA and protein level of the Nrf2 target gene NQO1, and the Keap1-Nrf2 PPI inhibitors reversed this effect. The reversal of E2 action by these compounds was not due to binding to ER as ER antagonists. Further, a selected compound attenuated oxidative stress induced by E2, determined by the level of a biomarker 8-oxo-deoxyguanosine. These findings suggest that the Keap1-Nrf2 PPI inhibitors have potent antioxidant activity by activating Nrf2 pathways and inhibit E2-induced gene and protein expression. These compounds may serve as potential chemopreventive agents in estrogen-stimulated breast cancer.

Anti-diabetic activities of phenolic compounds of Alternaria sp., an endophyte isolated from the leaves of desert plants growing in Egypt.

Six phenolic compounds (talaroflavone (1), alternarienoic acid (2), altenuene (3), altenusin (4), alternariol (5), and alternariol-5-O-methyl ether (6)) were isolated from the solid rice culture media of Alternaria sp., an endophyte isolated from the fresh leaves of three desert plants, Lycium schweinfurthii Dammer (Solanaceae), Pancratium maritimum L. (Amaryllidaceae) and Cynanchum acutum L. (Apocynaceae). Compounds 2, 3, and 4 exhibited potent α-glucosidase and lipase inhibitory activities suggesting that they might act as naturally occurring anti-diabetic candidates. The same compounds showed potent binding in the active site for both enzymes with desirable pharmacokinetic properties. The isolated bioactive compounds were not exclusive to a certain host plant which reveals the dominant ecological standpoints for consequent optimization. This could lead to a cost-effective and reproducible yield applicable to commercial scale-up.

Combination of ligand and structure based virtual screening approaches for the discovery of potential PARP1 inhibitors.

Poly (ADP-ribose) polymerase 1 (PARP1) has high therapeutic value as biomolecular target for research and development of small molecules with antineoplastic activity, since it is upregulated in many cancers, especially in ovarian and BRCA 1/2 mutated breast cancers. Decades of investigation of PARP inhibitors (PARPi) have led to the approval of several drug compounds, however clinical application of PARPi in cancer therapy is limited due to a number of factors, including low selectivity, weak affinity and undesired side effects. Thus, identification of novel drug-like chemical compounds with alternatives to the known PARPi chemical scaffolds, binding modes and interaction patterns with amino acid residues in the active site is of high therapeutic importance. In this study we applied a combination of ligand- and structure-based virtual screening approaches with the goal of identification of novel potential PARPi.

Optimization of 1,4-bis(arylsulfonamido)naphthalene-N,N'-diacetic acids as inhibitors of Keap1-Nrf2 protein-protein interaction to suppress neuroinflammation.

The protein-protein interaction (PPI) between kelch-like ECH-associated protein 1 (Keap1) and nuclear factor erythroid 2-related factor 2 (Nrf2) is recognized as a promising target for the prevention and treatment of oxidative stress-related inflammatory diseases. Herein, a series of novel 1,4-bis(arylsulfonamido)naphthalene-N,N'-diacetic acid analogs (7p-t and 8c) were designed to further explore the structure-activity relationships of the series. Their activities were measured first with a fluorescence polarization (FP) assay and more potent compounds were further evaluated using a more sensitive time-resolved fluorescence energy transfer (TR-FRET) assay, demonstrating IC50 values between 7.2 and 31.3 nM. In cytotoxicity studies, the naphthalene derivatives did not show noticeable toxicity to human HepG2-C8 and mouse brain BV-2 microglia cells. Among them, compound 7q bearing oxygen-containing fused rings was shown to significantly stimulate the cellular Nrf2 signaling pathway, including activation of antioxidant response element (ARE)-controlled expression of Nrf2 target genes and proteins. More importantly, 7q suppressed up-regulation of several pro-inflammatory cytokines in lipopolysaccharide (LPS)-challenged BV-2 microglial cells, representing a potential therapeutic application for controlling neuroinflammatory disorders.

Detection of Chromosomal and Plasmid-Mediated Quinolone Resistance Among Escherichia coli Isolated from Urinary Tract Infection Cases; Zagazig University Hospitals, Egypt.

INTRODUCTION: Resistance to fluoroquinolones (FQ) in uropathogenic Escherichia coli (UPEC) has emerged as a growing problem. Chromosomal mutations and plasmid-mediated quinolone resistance (PMQR) determinants have been implicated. Data concerning the prevalence of these determinants in UPEC in our hospital are quite limited. PURPOSE: To investigate the occurrence and genetic determinants of FQ resistance in UPEC isolated from urinary tract infection (UTI) cases in Zagazig University Hospitals. PATIENTS AND METHODS: Following their isolation, the identification and susceptibility of UPEC isolates were performed by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometer (MALDI-TOF MS). FQ resistance was detected by the disc diffusion method. Ciprofloxacin minimal inhibitory concentration (MIC) was determined using E-test. Chromosomal mutations in the gyrA gene were detected using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), and for detection of PMQR, a couple of multiplex PCR reactions were used. RESULTS: Among a total of 192 UPEC isolates, 46.9% (n=90) were FQ resistant. More than half of the isolates (57.8%) exhibited high-level ciprofloxacin resistance (MIC > 32 µg/mL). Mutations in gyrA were detected in 76.7% of isolates, with 34.4% having mutations at more than one site. PMQR determinants were detected in 80.1% of UPEC isolates, with aac(6')-Ib-cr gene being the most frequent found in 61.1% of isolates. CONCLUSION: There is a high prevalence of both gyrA mutations and PMQR determinants among UPEC isolates in our hospital which contribute to high-level ciprofloxacin resistance, a finding that may require the revision of the antibiotics used for empirical treatment of UTI.

Myocardial Injury in Children with Unoperated Congenital Heart Diseases.

Background. Children with congenital heart diseases (CHDs) may have a risk of developing myocardial injury caused by volume and pressure overload. Objective. To evaluate the incidence of myocardial injury in children with cyanotic and acyanotic CHDs using cTnI assay and to correlate it with different hemodynamic parameters. Methods. This study included 80 children with CHDs (40 acyanotic and 40 cyanotic) as well as 40 healthy children (control group). Serum cTnI levels were measured for patients and control. Pulmonary to systemic blood flow (Qp/Qs) and pulmonary to systemic arterial pressure (Pp/Ps) ratios were measured for children with CHDs during cardiac catheterization. Results. Sixty-four out of 80 patients with CHDs had myocardial injury as evidenced by increased cTnI. Serum cTnI was significantly higher in both cyanotic and acyanotic groups compared to control group (p < 0.05). Serum cTnI level significantly correlated with oxygen saturation (SpO2), ejection fraction (EF), Qp/Qs, and Pp/Ps ratios. Conclusion. The incidence of myocardial injury was high in children with CHDs. The use of cTnI for follow-up of children with CHDs may help early detection of myocardial injury and help early management of these cases.

Synthesis, in vitro anticancer evaluation and in silico studies of novel imidazo[2,1-b]thiazole derivatives bearing pyrazole moieties.

A series of imidazo[2,1-b]thiazoles bearing pyrazole moieties 4-6(a-c) was synthesized through the reaction of 6-hydrazinylimidazo[2,1-b]thiazoles 3a-c with different ß-dicarbonyl compounds. Eleven compounds were screened at the National Cancer Institute (NCI), USA for anticancer activity at a single dose (10 µM). The in vitro anticancer evaluation revealed that compounds 2a and 4-6(a) exhibited increased potency towards CNS SNB-75 and Renal UO-31 cancer cell lines. COMPARE analyses showed strong to considerable correlations with rapamycin (mTOR inhibitor). The results of assessment of toxicities, druglikeness, and drug score profiles of compounds 2a and 4-6(a) are promising. Some of the target compounds showed good docking scores with potential anticancer targets, chosen based on pharmacophore mapping of the established derivatives.

Novel acetamidothiazole derivatives: synthesis and in vitro anticancer evaluation.

A novel series of acetamide derivatives possessing both 2-imino-4-arylthiazoles and morpholine or different piperazines were synthesized and characterized by IR, (1)H NMR, (13)C NMR, elemental and mass spectral analyses. Twelve compounds were granted NSC codes at National Cancer Institute (NCI), USA for anticancer activity at a single high dose (10(-5) M) in full NCI 60 cell panel. Among the compounds tested, compounds 5a and 6b were found to be the most active candidates of the synthesized series. Assessment of toxicities, druglikeness, and drug score profiles of compounds 5a and 6b are promising. Some of the synthesized compounds showed a good docking score with potential anticancer targets, chosen based on pharmacophore mapping of the established derivatives.