Development of pyrolo[2,3-c]pyrazole, pyrolo[2,3-d]pyrimidine and their bioisosteres as novel CDK2 inhibitors with potent in vitro apoptotic anti-proliferative activity: Synthesis, biological evaluation and molecular dynamics investigations.

Inhibiting the CDK2/cyclin A2 enzyme has been validated in multiple clinical manifestations related to multiple types of cancer. Herein, novel series of pyrolo[2,3-c]pyrazole, pyrolo[2,3-c]isoaxazole and pyrolo[2,3-d]pyrimidine, pyrolo[3,2-c]pyridine & indole based analogs were designed, synthesized and biologically evaluated for their in vitro antiproliferative activity where the obtained results revealed that most of the newly synthesized compounds showed significant cytotoxic activity towards MCF-7 (breast cancer cell lines) and HepG-2 (hepatocellular carcinoma) with IC50 ranging from 3.20 µM to 10.05 µM & from 2.18 µM to 13.49 µM, respectively, compared to that of Sorafenib (IC50 9.76 & 13.19 µM, respectively). The in vitro inhibitory profile of the most promising compounds (9, 11, 14, 15, 16, 17 and 20) towards CDK2/CyclinA2 was evaluated. Compounds 14 & 15 exhibited potent inhibitory profile against CDK2 with (IC50 0.11 and 0.262 µM, respectively comparable to Sorafenib IC50 0.184 µM. Western blotting of 14 & 15 at MCF-7 cell line confirmed the diminishing activity on CDK2. Furthermore, both compounds exserted a significant cell cycle arrest and apoptosis. Moreover, the normal cell line cytotoxicity for both compounds revealed low cytotoxic results in normal cells rather than cancer cells. Molecular docking and dynamic simulation validated the potentiality of the newly synthesized compounds to have high binding affinity within CDK2 binding pocket. 3DQSAR pharmacophore, in-silico ADME/TOPKAT studies and drug-likeness showed proper pharmacokinetic properties and helped in structure requirements prediction. The obtained model and pattern of substitution could be used for further development of CDK2 inhibitors.

Synthesis, biological evaluation, and in silico studies of new CDK2 inhibitors based on pyrazolo[3,4-d]pyrimidine and pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidine scaffold with apoptotic activity.

Cyclin-dependent kinase inhibition is considered a promising target for cancer treatment for its crucial role in cell cycle regulation. Pyrazolo pyrimidine derivatives were well established for their antitumor activity via CDK2 inhibition. In this research, new series of pyrazolopyrimidine derivatives (4-15) was designed and synthesised as novel CDK2 inhibitors. The anti-proliferative activities against MCF-7, HCT-116, and HepG-2 were used to evaluate their anticancer activity as novel CDK2 inhibitors. Most of the compounds showed superior cytotoxic activity against MCF-7 and HCT-116 compared to Sorafenib. Only compounds 8, 14, and 15 showed potent activity against HepG-2. The CDK2/cyclin A2 enzyme inhibitory activity was tested for all synthesised compounds. Compound 15 showed the most significant inhibitory activity with IC50 0.061 ± 0.003 µM. It exerted remarkable alteration in Pre G1 and S phase cell cycle progression and caused apoptosis in HCT cells. In addition, the normal cell line cytotoxicity for compound 15 was assigned revealing low cytotoxic results in normal cells rather than cancer cells. Molecular docking was achieved on the designed compounds and confirmed the two essential hydrogen binding with Leu83 in CDK2 active site. In silico ADMET studies and drug-likeness showed proper pharmacokinetic properties which helped in structure requirements prediction for the observed antitumor activity.

Discovery of potent thieno[2,3-d]pyrimidine VEGFR-2 inhibitors: Design, synthesis and enzyme inhibitory evaluation supported by molecular dynamics simulations.

Vascular endothelial growth factor receptor (VEGFR) is one of the well-known targets that control angiogenesis and cancer progression. In this study, we are reporting the design, synthesis and biological evaluation of a series of 4-substituted thieno[2,3-d]pyrimidine derivatives as VEGFR-2 inhibitors. The design of these compounds was based on interactions extracted from crystal structure of potent pyrrolo[3,2-d]pyrimidine inhibitor VIII with VEGFR-2 (PDB: 3VHE). In addition to these interactions, the new compounds were also designed to interact with residues in the solvent accessible region such as Asn923. Accordingly, the thienopyrimidine target compounds were synthesized and subjected to VEGFR-2 enzyme inhibition assay. Several target compounds (7d-f, 8b-c, 8e-g and 15c) exhibited potent inhibitory activities against VEGFR-2 with IC50 values in low nanomolar range. Compounds 8b and 8e revealed exceptionally potent inhibitory activity with IC50 of 5 and 3.9 nM, respectively. The molecular docking analysis and molecular dynamics simulation were also performed to further investigate these findings.

Design and Synthesis of New CDK2 Inhibitors Containing Thiazolone and Thiazolthione Scafold with Apoptotic Activity.

Cyclin dependent kinase 2 (CDK2) inhibition is a well-established strategy for treating cancer. Different series of novel thiazolone (1, 7-9) together with fused thiazolthione (2-6, and 10) derivatives were designed, then synthesized and evaluated for their biological inhibitory activity against CDK2. Additionally, the cytotoxicity of the new compounds was explored against breast and colon cancer cell lines. The novel thiazolone and the fused thiazolthione derivatives exhibited potent CDK2/cyclin A2 inhibitory effect of an IC50 values ranging 105.39-742.78 nM. Amongst them compounds 4 and 6 revealed highest IC50 of 105.39 and 139.27 nM, respectively. Most compounds showed significant inhibition on both breast cancer and colon cancer cell lines with IC50 range 0.54-5.26 and 0.83-278 µM, respectively. Further investigations involved flow cytometry analysis on MCF-7 cancer cell line for compounds 5 and 7 which resulted in arrest cell-cycle at two phases Pre G1/G2-M and re-enforced apoptosis via activation of caspase-7. Molecular modeling simulation of the designed compounds revealed that they were well fitted into CDK2 active site and their complexes were stabilized through the essential hydrogen bonding. Three dimensional quantitative structure activity relationship (3D QSAR) pharmacophore, and absorption, distribution, metabolism, excretion, and toxicity (ADMET) studies were also carried out showing proper pharmacokinetic and drug-likeness which aided in the prediction of the structure requirements responsible for the observed antitumor activity.

Discovery of New Pyrazolopyridine, Furopyridine, and Pyridine Derivatives as CDK2 Inhibitors: Design, Synthesis, Docking Studies, and Anti-Proliferative Activity.

New pyridine, pyrazoloyridine, and furopyridine derivatives substituted with naphthyl and thienyl moieties were designed and synthesized starting from 6-(naphthalen-2-yl)-2-oxo-4-(thiophen-2-yl)-1,2-dihydropyridine-3-carbonitrile (1). The chloro, methoxy, cholroacetoxy, imidazolyl, azide, and arylamino derivatives were prepared to obtain the pyridine--C2 functionalized derivatives. The derived pyrazolpyridine-N-glycosides were synthesized via heterocyclization of the C2-thioxopyridine derivative followed by glycosylation using glucose and galactose. The furopyridine derivative 14 and the tricyclic pyrido[3',2':4,5]furo[3,2-d]pyrimidine 15 were prepared via heterocyclization of the ester derivative followed by a reaction with formamide. The newly synthesized compounds were evaluated for their ability to in vitro inhibit the CDK2 enzyme. In addition, the cytotoxicity of the compounds was tested against four different human cancer cell lines (HCT-116, MCF-7, HepG2, and A549). The CDK2/cyclin A2 enzyme inhibitory results revealed that pyridone 1, 2-chloro-6-(naphthalen-2-yl)-4-(thiophen-2-yl)nicotinonitrile (4), 6-(naphthalen-2-yl)-4-(thiophen-2-yl)-1H-pyrazolo[3,4-b]pyridin-3-amine (8), S-(3-cyano-6-(naphthaen-2-yl)-4-(thiophen-2-yl)pyridin-2-yl) 2-chloroethanethioate (11), and ethyl 3-amino-6-(naphthalen-2-yl)-4-(thiophen-2-yl)furo[2,3-b]pyridine-2-carboxylate (14) are among the most active inhibitors with IC50 values of 0.57, 0.24, 0.65, 0.50, and 0.93 µM, respectively, compared to roscovitine (IC50 0.394 µM). Most compounds showed significant inhibition on different human cancer cell lines (HCT-116, MCF-7, HepG2, and A549) with IC50 ranges of 31.3-49.0, 19.3-55.5, 22.7-44.8, and 36.8-70.7 µM, respectively compared to doxorubicin (IC50 40.0, 64.8, 24.7 and 58.1 µM, respectively). Furthermore, a molecular docking study suggests that most of the target compounds have a similar binding mode as a reference compound in the active site of the CDK2 enzyme. The structural requirements controlling the CDK2 inhibitory activity were determined through the generation of a statistically significant 2D-QSAR model.

Potential Role of Colchicine in Combating COVID-19 Cytokine Storm and Its Ability to Inhibit Protease Enzyme of SARS-CoV-2 as Conferred by Molecular Docking Analysis.

Despite the advance in the management of Coronavirus disease 2019 (COVID-19), the global pandemic is still ongoing with a massive health crisis. COVID-19 manifestations may range from mild symptoms to severe life threatening ones. The hallmark of the disease severity is related to the overproduction of pro-inflammatory cytokines manifested as a cytokine storm. Based on its anti-inflammatory activity through interfering with several pro and anti-inflammatory pathways, colchicine had been proposed to reduce the cytokine storm and subsequently improve clinical outcomes. Molecular docking analysis of colchicine against RNA-dependent RNA polymerase (RdRp) and protease enzymes of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) revealed that colchicine provided a grid-based molecular docking method, C-DOCKER interaction energy 64.26 and 47.53 (Kcal/mol) with protease and RdRp, respectively. This finding indicated higher binding stability for colchicine-protease complexes than the colchicine-RdRp complex with the involvement of seven hydrogen bonds, six hydrogen acceptors with Asn142, Gly143, Ser144, and Glu166 and one hydrogen-bond donors with Cys145 of the protease enzyme. This is in addition to three hydrophobic interactions with His172, Glu166, and Arg188. A good alignment with the reference compound, Boceprevir, indicated high probability of binding to the protease enzyme of SARS-CoV-2. In conclusion, colchicine can ameliorate the destructive effect of the COVID-19 cytokine storm with a strong evidence of antiviral activity by inhibiting the protease enzyme of SARS-CoV-2.

Alkaloids: Therapeutic Potential against Human Coronaviruses.

Alkaloids are a class of natural products known to have wide pharmacological activity and have great potential for the development of new drugs to treat a wide array of pathologies. Some alkaloids have antiviral activity and/or have been used as prototypes in the development of synthetic antiviral drugs. In this study, eleven anti-coronavirus alkaloids were identified from the scientific literature and their potential therapeutic value against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is discussed. In this study, in silico studies showed an affinity of the alkaloids for binding to the receptor-binding domain of the SARS-CoV-2 spike protein, putatively preventing it from binding to the host cell. Lastly, several mechanisms for the known anti-coronavirus activity of alkaloids were discussed, showing that the alkaloids are interesting compounds with potential use as bioactive agents against SARS-CoV-2.

Design, synthesis and biological evaluation of certain CDK2 inhibitors based on pyrazole and pyrazolo[1,5-a] pyrimidine scaffold with apoptotic activity.

Different series of novel pyrazole and pyrazolo[1,5-a] pyrimidine derivatives (2a-g), (3a-c), (7a-d) and (10a-e) were designed, synthesized and evaluated for their ability to inhibit CDK2/cyclin A2 enzyme in vitro. In addition, the cytotoxicity of the newly synthesized compounds was screened against four different human cancer cell lines. The CDK2/cyclin A2 enzyme inhibitory activity revealed that compounds (2d) and (2 g) are among the most active with inhibitory activity values of 60% and 40%, respectively, while compounds (7d) and (10b) exhibited the highest activity among the newly synthesized derivatives against four tumor cell lines (HepG2, MCF-7, A549 and Caco2) with IC50 values 24.24, 14.12, 30.03 and 29.27 µM and 17.12, 10.05, 29.95 and 25.24 µM, respectively. Flow cytometry cell cycle assay was carried for compounds (7d) and (10b) to investigate their apoptotic activity. The obtained results revealed that they induced cell-cycle arrest in the G0-G1phase and reinforced apoptotic DNA fragmentation. Molecular modeling studies have been carried out to gain further understanding the binding mode of the target compounds together with field alignment to define the similar field properties.

Design, synthesis and molecular modeling study of certain VEGFR-2 inhibitors based on thienopyrimidne scaffold as cancer targeting agents.

Different series of novel thieno [2,3-d]pyrimidine derivative (9a-d,10a-f,l,m and 15a-m) were designed, synthesized and evaluated for their ability to in vitro inhibit VEGFR-2 enzyme. Also, the cytotoxicity of the final compounds was tested against a panel of 60 different human cancer cell lines by NCI. The VEGFR-2 enzyme inhibitory results revealed that compounds 10d, 15d and 15 g are among the most active inhibitors with IC50 values of 2.5, 5.48 and 2.27 µM respectively, while compound 10a remarkably showed the highest cell growth inhibition with mean growth inhibition (GI) percent of 31.57%. It exhibited broad spectrum anti-proliferative activity against several NCI cell lines specifically on human breast cancer (T7-47D) and renal cancer (A498) cell lines of 85.5% and 77.65% inhibition respectively. To investigate the mechanistic aspects underlying the activity, further biological studies like flow cytometry cell cycle together with caspase-3 colorimetric assays were carried on compound 10a. Flow cytometric analysis on both MCV-7 and PC-3 cancer cells revealed that it induced cell-cycle arrest in the G0-G1phase and reinforced apoptosis via activation of caspase-3. Furthermore, molecular modeling studies have been carried out to gain further understanding of the binding mode in the active site of VEGFR-2 enzyme and predict pharmacokinetic properties of all the synthesized inhibitors.

Design and Synthesis of New Quinoxaline Derivatives as Anticancer Agents and Apoptotic Inducers.

The quinoxaline scaffold is a promising platform for the discovery of active chemotherapeutic agents. Three series of quinoxaline derivatives were synthesized and biologically evaluated against three tumor cell lines (HCT116 human colon carcinoma, HepG2, liver hepatocellular carcinoma and MCF-7, human breast adenocarcinoma cell line), in addition to VEGFR-2 enzyme inhibition activity. Compounds VIId, VIIIa, VIIIc, VIIIe and XVa exhibited promising activity against the tested cell lines and weak activity against VEGFR-2. Compound VIIIc induced a significant disruption in the cell cycle profile and cell cycle arrest at the G2/M phase boundary. In further assays, the cytotoxic effect of the highly active compounds was determined using a normal Caucasian fibroblast-like fetal lung cell line (WI-38). Compound VIIIc could be considered as a lead compound that merits further optimization and development as an anti-cancer and an apoptotic inducing candidate against the HCT116 cell line.

BSACI guideline for the diagnosis and management of allergic and non-allergic rhinitis (Revised Edition 2017; First edition 2007).

This is an updated guideline for the diagnosis and management of allergic and non-allergic rhinitis, first published in 2007. It was produced by the Standards of Care Committee of the British Society of Allergy and Clinical Immunology, using accredited methods. Allergic rhinitis is common and affects 10-15% of children and 26% of adults in the UK, it affects quality of life, school and work attendance, and is a risk factor for development of asthma. Allergic rhinitis is diagnosed by history and examination, supported by specific allergy tests. Topical nasal corticosteroids are the treatment of choice for moderate to severe disease. Combination therapy with intranasal corticosteroid plus intranasal antihistamine is more effective than either alone and provides second line treatment for those with rhinitis poorly controlled on monotherapy. Immunotherapy is highly effective when the specific allergen is the responsible driver for the symptoms. Treatment of rhinitis is associated with benefits for asthma. Non-allergic rhinitis also is a risk factor for the development of asthma and may be eosinophilic and steroid-responsive or neurogenic and non- inflammatory. Non-allergic rhinitis may be a presenting complaint for systemic disorders such as granulomatous or eosinophilic polyangiitis, and sarcoidoisis. Infective rhinitis can be caused by viruses, and less commonly by bacteria, fungi and protozoa.

A study of the allosteric inhibition of HCV RNA-dependent RNA polymerase and implementing virtual screening for the selection of promising dual-site inhibitors with low resistance potential.

Structure-based pharmacophores were generated and validated using the bioactive conformations of different co-crystallized enzyme-inhibitor complexes for allosteric palm-1 and thumb-2 inhibitors of NS5B. Two pharmacophore models were obtained, one for palm-1 inhibitors with sensitivity = 0.929 and specificity = 0.983, and the other for thumb-2 inhibitors with sensitivity = 1 and specificity = 0.979. In addition, a quantitative structure activity relationship (QSAR) models were developed based on using the values of different scoring functions as descriptors predicting the activity on both allosteric binding sites (palm-1 and thumb-2). QSAR studies revealed good predictive and statistically significant two descriptor models (r2 = .837, r2adjusted = .792 and r2prediction = .688 for palm-1 model and r2 = .927, r2adjusted = .908 and r2prediction = .779 for thumb-2 model). External validation for the QSAR models assured their prediction power with r2ext = .72 and .89 for palm-1 and thumb-2, respectively. Different docking protocols were examined for their validity to predict the correct binding poses of inhibitors inside their respective binding sites. Virtual screening was carried out on ZINC database using the generated pharmacophores, the selected valid docking algorithms and QSAR models to find compounds that could theoretically bind to both sites simultaneously.

Medicinal Attributes of Thienopyrimidine Based Scaffold Targeting Tyrosine Kinases and Their Potential Anticancer Activities.

Thienopyrimidines (TP), comprising a thiophene ring fused with pyrimidine, are famous bioisosteres to purines, an essential part of the human metabolome. This scaffold has become an interesting structural element in the development of pharmaceutical compounds, due to their wide spectrum applications as cytotoxic agents against different types of human cancer cell lines, cGMP phosphodiesterase inhibitors, and anti-viral, anti-inflammatory, and anti-microbial agents. The structural similarity of this scaffold with adenine made it an excellent moiety to be used in the design of kinase inhibitors. This review focuses on the chemistry of thienopyrimidine derivatives, their potential activities against various kinases, and their structure-activity relationship studies.

Quinoxaline-Based Scaffolds Targeting Tyrosine Kinases and Their Potential Anticancer Activity.

Quinoxaline derivatives, also called benzopyrazines, are an important class of heterocyclic compounds. Quinoxalines have drawn great attention due to their wide spectrum of biological activities. They are considered as an important basis for anticancer drugs due to their potential activity as protein kinase inhibitors. In this review, we focus on the chemistry of the quinoxaline derivatives, the strategies for their synthesis, their potential activities against various tyrosine kinases, and on the structure-activity relationship studies reported to date.

BSACI guideline for the management of chronic urticaria and angioedema.

This guidance for the management of patients with chronic urticaria and angioedema has been prepared by the Standards of Care Committee of the British Society for Allergy and Clinical Immunology (BSACI). The guideline is based on evidence as well as on expert opinion and is aimed at both adult physicians and paediatricians practising in allergy. The recommendations are evidence graded. During the development of these guidelines, all BSACI members were included in the consultation process using a Web-based system. Their comments and suggestions were carefully considered by the Standards of Care Committee. Where evidence was lacking, a consensus was reached by the experts on the committee. Included in this management guideline are clinical classification, aetiology, diagnosis, investigations, treatment guidance with special sections on children with urticaria and the use of antihistamines in women who are pregnant or breastfeeding. Finally, we have made recommendations for potential areas of future research.

Management of allergy to penicillins and other beta-lactams.

The Standards of Care Committee of the British Society for Allergy and Clinical Immunology (BSACI) and an expert panel have prepared this guidance for the management of immediate and non-immediate allergic reactions to penicillins and other beta-lactams. The guideline is intended for UK specialists in both adult and paediatric allergy and for other clinicians practising allergy in secondary and tertiary care. The recommendations are evidence based, but where evidence is lacking, the panel reached consensus. During the development of the guideline, all BSACI members were consulted using a Web-based process and all comments carefully considered. Included in the guideline are epidemiology of allergic reactions to beta-lactams, molecular structure, formulations available in the UK and a description of known beta-lactam antigenic determinants. Sections on the value and limitations of clinical history, skin testing and laboratory investigations for both penicillins and cephalosporins are included. Cross-reactivity between penicillins and cephalosporins is discussed in detail. Recommendations on oral provocation and desensitization procedures have been made. Guidance for beta-lactam allergy in children is given in a separate section. An algorithm to help the clinician in the diagnosis of patients with a history of penicillin allergy has also been included.

Rational design, synthesis and molecular modeling studies of novel anti-oncological alkaloids against melanoma.

3D-pharmacophore and 2D-QSAR modeling studies describe the anti-oncological properties of spiro-alkaloids. The dispiro[2H-indene-2,3'-pyrrolidine-2',3''-[3H]indole]-1,2''(1''H, 3H)-diones 20-38 were prepared via 1,3-dipolar cycloaddition reactions of azomethine ylides (generated in situ via decarboxylative condensation of isatins 7-9 with sarcosine 10) and 2-(arylmethylidene)-2,3-dihydro-1H-inden-1-ones 11-19 in refluxing ethanol. Some of the spiro-alkaloids (21, 22, 29 and 37) revealed potent antitumor properties against melanoma carcinoma cell lines (GaLa, LuPiCi and LuCa) utilizing the in vitro SRB standard method exhibiting potency close to that of the standard reference doxorubicin.

Synthesis, and QSAR analysis of anti-oncological active spiro-alkaloids.

QSAR study describes the anti-neoplastic spiro-alkaloids with relevant molecular descriptors using CODESSA III software. The dispiro[3H-indole-3,2'-pyrrolidine-3',3"-piperidines] 24-48 were synthesized via [3 + 2]-cycloaddition reaction of azomethine ylides, (generated in situ via decarboxylative condensation of isatins 21-23 with sarcosine) and 3E,5E-1-alkyl-3,5-bis(arylmethylidene)-4-piperidones 10-20. Some of the synthesized analogues exhibited promising antitumor properties against HELA (cervical), HEPG2 (liver), T-47D, MCF7 (breast), and HCT116 (colon) human tumor cell lines, demonstrating activity close to or even better than the standard Doxorubicin, based on in vitro Sulfo-Rhodamine-B bio-assay.

BSACI guideline for the diagnosis and management of cow's milk allergy.

This guideline advises on the management of patients with cow's milk allergy. Cow's milk allergy presents in the first year of life with estimated population prevalence between 2% and 3%. The clinical manifestations of cow's milk allergy are very variable in type and severity making it the most difficult food allergy to diagnose. A careful age- and disease-specific history with relevant allergy tests including detection of milk-specific IgE (by skin prick test or serum assay), diagnostic elimination diet, and oral challenge will aid in diagnosis in most cases. Treatment is advice on cow's milk avoidance and suitable substitute milks. Cow's milk allergy often resolves. Reintroduction can be achieved by the graded exposure, either at home or supervised in hospital depending on severity, using a milk ladder. Where cow's milk allergy persists, novel treatment options may include oral tolerance induction, although most authors do not currently recommend it for routine clinical practice. Cow's milk allergy must be distinguished from primary lactose intolerance. This guideline was prepared by the Standards of Care Committee (SOCC) of the British Society for Allergy and Clinical Immunology (BSACI) and is intended for clinicians in secondary and tertiary care. The recommendations are evidence based, but where evidence is lacking the panel of experts in the committee reached consensus. Grades of recommendation are shown throughout. The document encompasses epidemiology, natural history, clinical presentations, diagnosis, and treatment.

Management of hypersensitivity reactions to anti-D immunoglobulin preparations.

RhD immunoglobulin G (anti-D) administered to pregnant Rh(-) women prevents Rh isoimmunization. Its use has significantly reduced the incidence of haemolytic disease of the foetus and newborn previously responsible for one death in every 2200 births. In pregnancy, acute drug-induced hypersensitivity reactions including anaphylaxis can have serious deleterious effects on the mother and foetus/neonate. Women can be erroneously labelled as drug allergic as the investigation of hypersensitivity reactions in pregnancy is complex and drug challenges are usually contraindicated. We present three cases of suspected anti-D hypersensitivity clinically presenting as anaphylaxis and delayed transfusion-related reaction. We also propose a new algorithm for the investigations of such reaction. It relies on detailed history, cautious interpretation of skin tests, foetal Rh genotyping from maternal blood and, in some cases, anti-D challenges. This is not to deprive women of anti-D which might put their future pregnancies at risk.