Design and discovery of novel pyrazole-pyrrolopyrimidine derivatives as anti-glioma agents via promoting apoptosis, inhibiting cell cycle and EGFR-TK

Glioma is an aggressive type of brain malignancy responsible for significant morbidity and mortality. In the current scenario, epidermal growth factor receptor (EGFR) kinases targeted therapy showed significant benefits in glioma patients. Therefore, in the present study, we intend to investigate the anti-glioma potential of a novel class of pyrazole-pyrrolopyrimidine derivatives and their mechanism of action. The compounds will be synthesized in a straight-forward synthetic route in excellent yields and subsequently tested for EGFR kinase inhibition. The compounds showed a diverse range of inhibitory activity against EGFR (IC50  = 3.4-873.2 nM). With an IC50 of 1.5 nM, compound 4i was determined to be the most effective EGFR inhibitor, even superior to the standard erlotinib (IC50 2.3 nM). Among them, the three most potent compounds (4i, 4j, and 4k) were further subjected to the anticancer activity against the panel of various cancer cell lines MCF-7 (breast cancer), A549 (lung cancer), U87 (glioblastoma cell)-EGFR-Wild Type, U87 (mutant glioblastoma cells) EGFR-mutant cell, MCF-12A (normal cells). The compound 4i showed the most potent activity against glioblastoma cells as compared to other cancer cells. The effect of compound 4i was also studied on the apoptosis of U87 cells, where it showed induction of apoptosis in a concentration-dependent manner. It also showed inhibition of the G2/M cell cycle phase of U87 cells. Our study demonstrated the development of novel pyrazole-pyrrolopyrimidine derivatives as a novel class of anti-glioma agents.

Activation of multiple stress responses in Staphylococcus aureus substantially lowers the minimal inhibitory concentration when combining two novel antibiotic drug candidates

The past few decades have been plagued by an increasing number of infections caused by antibiotic resistant bacteria. To mitigate the rise in untreatable infections, we need new antibiotics with novel targets and drug combinations that reduce resistance development. The novel β-clamp targeting antimicrobial peptide BTP-001 was recently shown to have a strong additive effect in combination with the halogenated pyrrolopyrimidine JK-274. In this study, the molecular basis for this effect was examined by a comprehensive proteomic and metabolomic study of the individual and combined effects on Staphylococcus aureus. We found that JK-274 reduced activation of several TCA cycle enzymes, likely via increasing the cellular nitric oxide stress, and BTP-001 induced oxidative stress in addition to inhibiting replication, translation, and DNA repair processes. Analysis indicated that several proteins linked to stress were only activated in the combination and not in the single treatments. These results suggest that the strong additive effect is due to the activation of multiple stress responses that can only be triggered by the combined effect of the individual mechanisms. Importantly, the combination dose required to eradicate S. aureus was well tolerated and did not affect cell viability of immortalized human keratinocyte cells, suggesting a species-specific response. Our findings demonstrate the potential of JK-274 and BTP-001 as antibiotic drug candidates and warrant further studies.

Synthesis Strategies and Medicinal Value of Pyrrole and its Fused Heterocyclic Compounds

For several decades, interest in pyrrole and pyrrolopyrimidine derivatives increases owing to their biological importance, such as anti-tumor, anti-microbial, anti-inflammatory, anti-diabetic, anti-histaminic, anti-malarial, anti-Parkinson, antioxidant and anti-viral, specially recently against COVID-19. These tremendous biological features motivated scientists to discover more pyrrole and fused pyrrole derivatives, owing to the great importance of the pyrrole nucleus as a pharmacophore in many drugs, and motivated us to present this article, highlighting on the different synthetic pathways of pyrrole and its fused compounds specially pyrrolopyrimidine, as well as their medicinal value from 2017 till 2021.

Novel Substituted Purine Isosteres: Synthesis, Structure-Activity Relationships and Cytotoxic Activity Evaluation

A number of pyrrolo[2,3-c]pyridines, pyrrolo[3,2-d]pyrimidines and pyrazolo[4,3-d]pyrimidines were designed and synthesized as antiproliferative agents. The target compounds possessed selected substituents in analogous positions on the central scaffold that allowed the extraction of interesting SARs. The cytotoxic activity of the new derivatives was evaluated against prostatic (PC-3) and colon (HCT116) cell lines, and the most potent analogues showed IC₅₀ values in the nM to low µM range, while they were found to be non-toxic against normal human fibroblasts (WI-38). Flow cytometric analysis of DNA content revealed that the most promising derivative 14b caused a statistically significant accumulation of PC-3 cells at G₂/M phase and induced apoptosis in PC-3 cells.

Role of Fyn Kinase Inhibitors in Switching Neuroinflammatory Pathways

Fyn kinase is a member of the Src non-receptor tyrosine kinase family. Fyn is involved in multiple signaling pathways extending from cell proliferation and differentiation to cell adhesion and cell motility, and it has been found to be overexpressed in various types of cancers. In the central nervous system, Fyn exerts several different functions such as axon-glial signal transduction, oligodendrocyte maturation and myelination, and it is implicated in neuroinflammatory processes. Based on these premises, Fyn emerges as an attractive target in cancer and neurodegenerative disease therapy, particularly Alzheimer disease (AD), based on its activation by Aβ via cellular prion protein and its interaction with tau protein. However, Fyn is also a challenging target since the Fyn inhibitors discovered so far, due to the relevant homology of Fyn with other kinases, suffer from off-target effects. This review covers the efforts performed in the last decade to identify and optimize small molecules that effectively inhibit Fyn, both in enzymatic and in cell assays, including drug repositioning practices, as an opportunity of therapeutic intervention in neurodegeneration.

Cu(I)-azidopyrrolo[3,2-d]pyrimidine Catalyzed Glaser-Hay Reaction under Mild Conditions

The limitation of the CuAAC "click" reaction with a 2-azidopyridine substrate, owing to its equilibrium with a tetrazole isomer, is exploited herein for its utility in the Glaser-Hay reaction. A catalytic combination of a 2-azidopyridine analogue, 4-azido-5H-pyrrolo[3,2-d]pyrimidine, and CuI afforded homocoupled products of terminal alkynes, without any trace of triazole product, under mild conditions with a broad substrate scope. Emphasis on carbohydrate-based substrates appended to a propargylic group led to 1,3-diynes in good to excellent yields.

Structure-activity relationship of 7-aryl-2-anilino-pyrrolopyrimidines as Mer and Axl tyrosine kinase inhibitors

The TAM (Axl, Mer, and Tyro3) family is implicated in the survival and chemoresistance of tumours and has emerged as a potential therapeutic target. A novel series of 7-aryl-2-anilino-pyrrolopyrimidines were identified as potent Axl/Mer tyrosine kinase inhibitors without significant inhibition of Tyro3. A representative compound 27 exhibited IC₅₀ values of 2 nM and 16 nM for Mer and Axl, respectively, and considerable inhibition for Mer phosphorylation in cells. Docking studies suggested that the formation of a salt bridge between the nitrogen of the aniline moiety with ASP678 of the Mer kinase domain as well as an interaction with the hinge region that most kinase inhibitors have in common would be essential to retain activity. These results could provide useful information for finding promising inhibitors of Axl/Mer for the treatment of cancer.

Synthesis and Evaluation of Cytotoxic Activity of Some Pyrroles and Fused Pyrroles

AIMS

Pyrrole derivatives represent a very interesting class as biologically active compounds. The objective of our study was to investigate the cytotoxic and apoptotic effects and antioxidant activity of the newly synthesized pyrrole derivatives.

METHOD

A series of novel pyrroles and fused pyrroles (tetrahydroindoles, pyrrolopyrimidines, pyrrolopyridines and pyrrolotriazines) were synthesized and characterized using IR, 1H NMR, 13C NMR, MS and elemental analysis techniques. The antiproliferative activity of our synthesized compounds and their modulatory effect apoptotic pathway were investigated. The effect on cellular proliferation and viability was monitored by resazurin assay. Apoptotic effect was evaluated by caspase glo 3/7 assay. Synthesized compounds are then tested for their anticancer activities against three different cell lines representing three different tumor types, namely; the HepG-2 (Human hepatocellular liver carcinoma cell line), the human MCF-7 cell line (breast cancer) and the pancreatic resistant Panc-1 cells.

RESULT

Compounds Ia-e, IIe, and IXc, d showed a promising anti-cancer activity on all tested cell lines. Antioxidant and wound healing invasion assays were examined for promising anticancer candidate compounds.

Design and Synthesis of Novel Macrocyclic Mer Tyrosine Kinase Inhibitors

Mer tyrosine kinase (MerTK) is aberrantly elevated in various tumor cells and has a normal anti-inflammatory role in the innate immune system. Inhibition of MerTK may provide dual effects against these MerTK-expressing tumors through reducing cancer cell survival and redirecting the innate immune response. Recently, we have designed novel and potent macrocyclic pyrrolopyrimidines as MerTK inhibitors using a structure-based approach. The most active macrocycles had an EC50 below 40 nM in a cell-based MerTK phosphor-protein ELISA assay. The X-ray structure of macrocyclic analogue 3 complexed with MerTK was also resolved and demonstrated macrocycles binding in the ATP binding pocket of the MerTK protein as anticipated. In addition, the lead compound 16 (UNC3133) had a 1.6 h half-life and 16% oral bioavailability in a mouse PK study.

Distinguishing on-target versus off-target activity in early antibacterial drug discovery using a macromolecular synthesis assay

The macromolecular synthesis assay was optimized in both S. aureus and E. coli imp and used to define patterns of inhibition of DNA, RNA, protein, and cell wall biosynthesis of several drug classes. The concentration of drug required to elicit pathway inhibition differed among the antimicrobial agents tested, with inhibition detected at concentrations significantly below the minimum inhibitory concentration (MIC) for tedizolid; within 4-fold of the MIC for ciprofloxacin, cefepime, vancomycin, tetracycline, and chloramphenicol; and significantly above the MIC for rifampicin and kanamycin. In a DNA gyrase/topoisomerase IV structure-based drug design optimization program, the assay rapidly identified undesirable off-target activity within certain chemotypes, altering the course of the program to focus on the series that maintained on-target activity.