Novel Pyrazolo[3,4-d]pyrimidines as Potential Cytotoxic Agents: Design, Synthesis, Molecular Docking and CDK2 Inhibition

Novel curcumin-based analogues as potential VEGFR2 inhibitors with promising metallic loading nanoparticles: synthesis, biological evaluation, and molecular modelling investigation

VEGFR2 inhibition has been established as a therapeutic approach for managing cancer. A series of curcumin-based analogues were designed, synthesized, and screened for their anticancer activity against MCF-7 and HepG-2 cell lines and WISH normal cells. Compounds 4b, 4d, 4e, and 4f showed potent cytotoxicity against MCF-7 with IC50 values of 0.49, 0.14, 0.01, and 0.32 μM, respectively, compared to curcumin (IC50 = 13.8 μM) and sorafenib (IC50 = 2.13 μM). Interestingly, compound 4e, the most active compound, exhibited potent VEGFR2 inhibition with an IC50 value of 11.6 nM (96.5% inhibition) compared to sorafenib with an IC50 value of 30 nM (94.8% inhibition). Additionally, compound 4e significantly induced apoptotic cell death in MCF-7 cells by 41.1% compared to a control group (0.8%), halting cell division during the G2/M phase by 39.8% compared to the control (21.7%). Molecular docking-coupled dynamics simulations highlighted the bias of the VEGFR2 pocket towards compound 4e compared to other synthesized compounds. Predicting superior binding affinities and relevant interactions with the pocket's key residues recapitulated in vitro findings towards higher inhibition activity for compound 4e. Furthermore, compound 4e with adequate pharmacokinetic and drug-likeness profiles in terms of ADME and safety characteristics can serve as a promising clinical candidate for future lead optimization and development. Notably, 4e-Fe2O3-humic acid NPs exhibited potent cytotoxicity with IC50 values of 2.41 and 13.4 ng mL-1 against MCF-7 and HepG-2 cell lines, respectively. Hence, compound 4e and its Fe2O3-humic acid-NPs could be further developed as promising anti-breast cancer agents.

Pyrazolo[3,4-d]pyrimidine scaffold: A review on synthetic approaches and EGFR and VEGFR inhibitory activities

The pyrazolo[3,4-d]pyrimidine core has received a lot of interest from the medicinal chemistry community as a promising framework for drug design and discovery. It is an isostere of the adenine ring of adenosine triphosphate, which allows it to mimic kinase active site hinge region binding contacts. This scaffold has a wide pharmacological and biological value, one of which is as an anticancer agent. Many successful anticancer medicines have been designed and synthesized using pyrazolo[3,4-d]pyrimidine as a key pharmacophore. The main synthetic routes of pyrazolo[3,4-d]pyrimidines as well as their recent developments as promising anticancer agents acting as endothelial growth factor receptors and vascular endothelial growth factor receptor inhibitors, published in the time frame from 1999 to 2022, are summarized in this review to set the direction for the design and synthesis of novel pyrazolo[3,4-d]pyrimidine derivatives for clinical deployment in cancer treatment.

Pyrimidine-fused Dinitrogenous Penta-heterocycles as a Privileged Scaffold for Anti-Cancer Drug Discovery

Pyrimidine-fused derivatives that are the inextricable part of DNA and RNA play a key role in the normal life cycle of cells. Pyrimidine-fused dinitrogenous penta-heterocycles including pyrazolopyrimidines and imidazopyrimidines is a special class of pyrimidine-fused compounds contributing to an important portion in anti-cancer drug discovery, which have been discovered as core structure for promising anti-cancer agents used in clinic or clinical evaluations. Pyrimidine-fused dinitrogenous penta-heterocycles have become one privileged scaffold for anti-cancer drug discovery. This review consists of the recent progress of pyrimidine-fused dinitrogenous penta-heterocycles as anti-cancer agents and their synthetic strategies. In addition, this review also summarizes some key structure-activity relationships (SARs) of pyrimidine-fused dinitrogenous penta-heterocycle derivatives as anti-cancer agents.

The molecular determinants of R-roscovitine block of hERG channels

Human ether-à-go-go-related gene (Kv11.1, or hERG) is a potassium channel that conducts the delayed rectifier potassium current (I_Kr) during the repolarization phase of cardiac action potentials. hERG channels have a larger pore than other K⁺channels and can trap many unintended drugs, often resulting in acquired LQTS (aLQTS). R-roscovitine is a cyclin-dependent kinase (CDK) inhibitor that induces apoptosis in colorectal, breast, prostate, multiple myeloma, other cancer cell lines, and tumor xenografts, in micromolar concentrations. It is well tolerated in phase II clinical trials. R-roscovitine inhibits open hERG channels but does not become trapped in the pore. Two-electrode voltage clamp recordings from Xenopus oocytes expressing wild-type (WT) or hERG pore mutant channels (T623A, S624A, Y652A, F656A) demonstrated that compared to WT hERG, T623A, Y652A, and F656A inhibition by 200 μM R-roscovitine was ~ 48%, 29%, and 73% weaker, respectively. In contrast, S624A hERG was inhibited more potently than WT hERG, with a ~ 34% stronger inhibition. These findings were further supported by the IC₅₀ values, which were increased for T623A, Y652A and F656A (by ~5.5, 2.75, and 42 fold respectively) and reduced 1.3 fold for the S624A mutant. Our data suggest that while T623, Y652, and F656 are critical for R-roscovitine-mediated inhibition, S624 may not be. Docking studies further support our findings. Thus, R-roscovitine’s relatively unique features, coupled with its tolerance in clinical trials, could guide future drug screens.