Synthesis and anticancer activity studies of indolylisoxazoline analogues

Synthesis, biological evaluation and mechanism study of a novel indole-pyridine chalcone derivative as antiproliferative agent against tumor cells through dual targeting tubulin and HK2

Chalcones have the characteristics of simple structure, easy synthesis and potent anti-tumor activity. Herein, a small library of fifty-five novel indole-chalcone derivatives were rationally designed and facilely synthesized. Consequently, their antiproliferative activity was systematically evaluated. Among which, compound 26 exhibited the most potent antiproliferative activity, with IC50 value of 0.764 μM against MD-MBA-231 cells. Moreover, it displayed a 5-fold selectivity compared with normal human cells. Further investigation revealed that compound 26 bound at the colchicine binding site of tubulin, disrupted their fibrous structure, thereby blocking the progression of the cell cycle and inducing apoptosis. Molecular docking and cellular thermal shift assay (CETSA) experiments further demonstrated that compound 26 could specifically bind to hexokinase 2 (HK2) and inhibit its activity, leading to impaired mitochondrial function and hindered mitochondrial respiration. Based on the quantitative structure-activity relationship study, further structure modifications were performed. Employing biotin probe pull-down assays, we demonstrated that compound 26 exerted its antiproliferative activity through a dual targeting mechanism, which simultaneously disrupted microtubule function and inhibited HK2 activity. Taken together, these results highlighted that compound 26 might be a promising antiproliferative agent for human cancer therapy.

Novel isoxazoline-linked 1,3,4-thiadiazole hybrids as anticancer agents: Design, synthesis, biological evaluation, molecular docking, and molecular dynamics simulation

In the current study, natural (R)-carvone was utilized as a starting material for the efficient synthesis of two series of isoxazoline derivatives bearing the 1,3,4-thiadiazole moiety. The new compounds were obtained in good yields and were characterized by ¹ H and ¹³ C NMR and HRMS analysis. The newly synthesized monoterpenic isoxazoline 1,3,4-thiadiazole and their thiosemicarbazone intermediate derivatives were evaluated for their anticancer activity in four cancer cell lines (HT-1080, A-549, MCF-7, and MDA-MB-231). Most of the synthesized compounds exhibited moderate to high anticancer effects. Compound 13c showed the highest anticancer activity with IC₅₀ values ranging from 19.33 ± 1.81 to 34.81 ± 3.03 µM. Further investigation revealed that compounds 12e and 13c could inhibit the cell growth of HT-1080 and MCF-7 cells by inducing apoptosis through caspase-3/7 activation. The apoptotic effect was accompanied by an S phase and G2/M cell cycle arrest for 13c and 12e, respectively. Compounds 12e and 13c were assessed in silico using molecular docking and molecular dynamics. We found that compound 13c is moderately active against the caspase-3 protein, which triggers apoptosis via intrinsic and extrinsic routes, making compound 13c a promising candidate to activate the proapoptotic protein (caspase-3).

Synthesis, Anticancer Activity, Structure-Activity Relationship, and Molecular Modeling Studies of α-Mangostin Derivatives as hERα Inhibitor

α-Mangostin is one of the secondary metabolites in mangosteen pericarp, which has been reported to have anti-breast cancer activity. In our previous study, three α-mangostin derivatives were computationally designed as hERα antagonists. In this present study, the designed compounds were synthesized undergoing a benzoylation reaction between α-mangostin with three benzoyl chloride derivatives to produce three derivatives, namely, AMB-1, AMB-2, and AMB-10. The synthesized compounds were then evaluated for their antiproliferative activity against the MCF-7 breast cancer cell model with hERα as the protein target. The in vitro assay shows moderate activity (57-126 μM) for all derivatives. The dynamic behaviors of all ligands, including α-mangostin and 4-hydroxytamoxifen (4-OHT), were studied with 100 ns of MD simulation. The structure-activity relationship shows that although it does not entirely concord with the expected design, it can explain the trend of α-mangostin and its derivatives antiproliferative activities against MCF-7, which associates with hERα antagonism.

Ultrasound assisted synthesis of tetrazole based pyrazolines and isoxazolines as potent anticancer agents via inhibition of tubulin polymerization

In search of new active molecules against MCF-7, A549 and HepG2, tetrazole based pyrazoline and isoxazoline derivatives under both conventional and ultrasonic irradiation method were designed and efficiently synthesized. Structures of newly synthesized compounds 5a-h and 6a-h were characterized by ¹H NMR, ¹³C NMR, MS and elemental analysis. Several derivatives were found to be excellent cytotoxic against MCF-7, A549 and HepG2 cell lines characterized by lower IC₅₀ values (0.78-3.12 µg/mL). Compounds 5b and 5c demonstrated an antiproliferative effect comparable to that of CA-4. Western blot analysis revealed that, reported compounds accumulate more tubulin in the soluble fraction. Docking studies suggested that, binding of these compounds mimics at the colchicine site of tubulin. In vitro study revealed that the tetrazole based pyrazolines and isoxazolines may possess ideal structural requirements for further development of novel therapeutic agents.

The importance of indole and azaindole scaffold in the development of antitumor agents

With some indoles and azaindoles being successfully developed as anticancer drugs, the design and synthesis of indole and azaindole derivatives with remarkable antitumor activity has received increasing attention and significant progress has been made. This paper reviews the recent progress in the study of tumorigenesis, mechanism of actions and structure activity relationships about anticancer indole and azindole derivatives. Combining structure activity relationships and molecular targets-related knowledge, this review will help researchers design more effective, safe and cost-effective anticancer indoles and azindoles agents.