Synthesis, docking and biological activities of novel hybrids celecoxib and anthraquinone analogs as potent cytotoxic agents

Natural-Derived COX-2 Inhibitors as Anticancer Drugs: A Review of their Structural Diversity and Mechanism of Action

Cyclooxygenase-2 (COX-2) is a key-type enzyme playing a crucial role in cancer development, making it a target of high interest for drug designers. In the last two decades, numerous selective COX-2 inhibitors have been approved for various clinical conditions. However, data from clinical trials propose that the prolonged use of COX-2 inhibitors is associated with life-threatening cardiovascular side effects. The data indicate that a slight structural modification can help develop COX-2 selective inhibitors with comparative efficacy and limited side effects. In this regard, secondary metabolites from natural sources offer great hope for developing novel COX-2 inhibitors with potential anticancer activity. In recent years, various nature-derived organic scaffolds are being explored as leads for developing new COX-2 inhibitors. The current review attempts to highlight the COX-2 inhibition activity of some naturally occurring secondary metabolites, concerning their capacity to inhibit COX-1 and COX-2 enzymes and inhibit cancer development, aiming to establish a structure-activity relationship.

Recent advances in the development of celecoxib analogs as anticancer agents: A review

Celecoxib is a nonsteroidal anti-inflammatory drug (NSAID) designed to be a selective cyclooxygenase-2 (COX-2) inhibitor. It was approved by the U.S. Food and Drug Administration for the treatment of inflammatory diseases such as osteoarthritis and rheumatoid arthritis. Additionally, celecoxib demonstrated potent antitumor and chemopreventive effects in vitro, in vivo, and in patients. The mechanism of celecoxib's chemopreventive effect is still not fully identified, but it is assumed to be multifactorial. Celecoxib's anticancer activity has been described both as independent of and dependent on its COX-2 inhibitory activity. The current review summarizes the recent advances published between 2000 and 2022 on the structure-based optimization of celecoxib to develop compounds with promising anticancer activity. The structure-activity relationships of celecoxib analogs are discussed, which may be beneficial in the design and development of novel analogs as potent antiproliferative agents in the future.

In silico and in vitro Estimation of Structure and Biological Affinity of 1,3- Oxazoles: Fragment-to-fragment Approach

Background:

The fragment-to-fragment approach for the estimation of the biological af-finity of the pharmacophores with biologically active molecules has been proposed. It is the next step in the elaboration of molecular docking and using the quantum-chemical methods for the complex modeling of pharmacophores with biomolecule fragments.

Methods:

The parameter 0 was used to estimate the contribution of -electron interactions in bio-logical affinity. It is directly related to the position of the frontier levels and reflects the donor-accep-tor properties of the pharmacophores and stabilization energy of the [Pharm꞉BioM] complex.

Results:

By using quantum-chemical calculations, it was found that the stacking interaction of oxa-zoles with phenylalanine is 7-11 kcal/mol, while the energy of hydrogen bonding of oxazoles with the amino group of lysine is 5-9 kcal/mol. The fragment-to-fragment approach can be applied for the investigation of the dependence of biological affinity on the electronic structure of pharmacophores.

Conclusion:

The founded quantum-chemical regularities are confirmed with the structure-activity relationships of substituted oxazoles.

Journey of anthraquinones as anticancer agents - a systematic review of recent literature

Anthraquinones are privileged chemical scaffolds that have been used for centuries in various therapeutic applications. The anthraquinone moiety forms the core of various anticancer agents. However, the emergence of drug-resistant cancers warrants the development of new anticancer agents. The research endeavours towards new anthraquinone-based compounds are increasing rapidly in recent years. They are used as a core chemical template to achieve structural modifications, resulting in the development of new anthraquinone-based compounds as promising anticancer agents. Mechanistically, most of the anthraquinone-based compounds inhibit cancer progression by targeting essential cellular proteins. Herein, we review new anthraquinone analogues that have been developed in recent years as anticancer agents. This includes a systematic review of the recent literature (2005-2021) on anthraquinone-based compounds in cell-based models and key target proteins such as kinases, topoisomerases, telomerases, matrix metalloproteinases and G-quadruplexes involved in the viability of cancer cells. In addition to this, the developments in PEG-based delivery of anthraquinones and the toxicity aspects of anthraquinone derivatives are also discussed. The review dispenses a compact background knowledge to understanding anthraquinones for future research on the expansion of anticancer therapeutics.

Identification and Characterization of a Novel N- and O-Glycosyltransferase from Saccharopolyspora erythraea

Glycosyltransferases are important enzymes which are often used as tools to generate novel natural products. In this study, we describe the identification and characterization of an inverting N- and O-glycosyltransferase from Saccharopolyspora erythraea NRRL2338. When feeding experiments with 1,4-diaminoanthraquinone in Saccharopolyspora erythraea were performed, the formation of new compounds (U3G and U3DG) was observed by HPLC-MS. Structure elucidation by NMR revealed that U3G consists of two compounds, N₁-α-glucosyl-1,4-diaminoanthraquinone and N₁-β-glucosyl-1,4-diaminoanthraquinone. Based on UV and MS data, U3DG is a N₁,N₄-diglucosyl-1,4-diaminoanthraquinone. In order to find the responsible glycosyltransferase, gene deletion experiments were performed and we identified the glycosyltransferase Sace_3599, which belongs to the CAZy family 1. When Streptomyces albus J1074, containing the dTDP-d-glucose synthase gene oleS and the plasmid pUWL-A-sace_3599, was used as host, U3 was converted to the same compounds. Protein production in Escherichia coli and purification of Sace_3599 was carried out. The enzyme showed glycosyl hydrolase activity and was able to produce mono- and di-N-glycosylated products in vitro. When UDP-α-d-glucose was used as a sugar donor, U3 was stereoselective converted to N₁-β-glucosyl-1,4-diaminoanthraquinone and N₁,N₄-diglucosyl-1,4-diaminoanthraquinone. The use of 1,4-dihydroxyanthraquinone as a substrate in in vitro experiments also led to the formation of mono-glucosylated and di-glucosylated products, but in lower amounts. Overall, we identified and characterized a novel glycosyltransferase which shows glycohydrolase activity and the ability to glycosylate “drug like” structures forming N- and O-glycosidic bonds.

The Importance of Anthraquinone and Its Analogues and Molecular Docking Calculation

In drug-delivery systems containing nano-drug structures, targeting the tumorous tissue by anthraquinone molecules with high biological activity, and reaching and destroying tumors by their tumor-killing effect reveals remarkable results for the treatment of tumors. The various biological activities of anthraquinones and their derivatives depend on molecular conformation; hence, their intra-cell interaction mechanisms including deoxyribonucleic acid (DNA), ribonucleic acid (RNA), enzymes, and hormones. Computer-based drug design plays an important role in the design of drugs and the determination of goals for them. Molecular docking has been widely used in structure-based drug design. The effects of anthraquinone analogues in tumor cells as a result of their interaction with DNA strand has increased the number of studies done on them, and they have been shown to have a wide range of applications in chemistry, medicine, pharmacy, materials, and especially in the field of biomolecules.

Synthesis, characterization, and anticancer evaluation of some new N1-(anthraquinon-2-yl) amidrazone derivatives

A new series of novel N1-anthraquinon-2-yl amidrazones incorporating N-piperazines and related congeners were synthesized via reaction of the hydrazonoyl chloride derived from 2-qaminoanthraquinone with the appropriate piperazine (secondary amine). Structures of the new compounds were confirmed by a panel of spectroscopic methods including IR, NMR, and MS and by elemental analysis. The antitumor activity of the newly prepared compounds was evaluated in vitro against MCF-7 breast cancer, K562 chronic myelogenous leukemia, and dermal fibroblasts cell lines by means of a cell viability assay using the tetrazolium dye 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. Results revealed that compounds 13a and 13d exhibit the highest inhibitory activity against K562 and MCF-7 cell lines. These two compounds could be considered as promising as potential anticancer drugs.

Biological Validation of Novel Polysubstituted Pyrazole Candidates with in Vitro Anticancer Activities

With the aim of developing novel antitumor scaffolds, a novel series of polysubstituted pyrazole derivatives linked to different nitrogenous heterocyclic ring systems at the C-4 position were synthesized through different chemical reactions and characterized by means of spectral and elemental analyses and their antiproliferative activity against 60 different human tumor cell lines was validated by the U.S. National Cancer Institute using a two stage process. The in vitro anticancer evaluation revealed that compound 9 showed increased potency toward most human tumor cell lines with GI₅₀MG-MID = 3.59 µM, as compared to the standard drug sorafenib (GI₅₀ MG-MID = 1.90 µM). At the same time, compounds 6a and 7 were selective against the HOP-92 cell line of non-small cell lung cancer with GI₅₀ 1.65 and 1.61 µM, respectively.