Breast cancer is the most common cancer in women, responsible for over half a million deaths in 2020. Almost 75% of FDA-approved drugs are mainly nitrogen- and sulfur-containing heterocyclic compounds, implying the importance of such compounds in drug discovery. Among heterocycles, thiazole-based heterocyclic compounds have demonstrated a broad range of pharmacological activities. In the present study, a novel set of 1,3-thiazole derivatives was designed and synthesized based on the coupling of acetophenone derivatives, and phenacyl bromide was substituted as a key reaction step. The activity of synthesized compounds was screened against the proliferation of two breast cancer cell lines (MCF-7 and MDA-MB-231). Almost all compounds exhibited a considerable antiproliferative activity toward the breast cancer cells as compared to staurosporine, with no significant cytotoxicity toward the epithelial cells. Among the synthesized compounds, compound 4 exhibited the most potent antiproliferative activity, with an IC₅₀ of 5.73 and 12.15 µM toward MCF-7 and MDA-MB-231 cells, respectively, compared to staurosporine (IC₅₀ = 6.77 and 7.03 µM, respectively). Exploring the mechanistic insights responsible for the antiproliferative activity of compound 4 revealed that compound 4 possesses a significant inhibitory activity toward the vascular endothelial growth factor receptor-2 (VEGFR-2) with (IC₅₀ = 0.093 µM) compared to Sorafenib (IC₅₀ = 0.059 µM). Further, compound 4 showed the ability to induce programmed cell death by triggering apoptosis and necrosis in MCF-7 cells and to induce cell cycle arrest on MCF-7 cells at the G1 stage while decreasing the cellular population in the G2/M phase. Finally, detailed in silico molecular docking studies affirmed that this class of compounds possesses a considerable binding affinity toward VEGFR2 proteins. Overall, these results indicate that compound 4 could be a promising lead compound for developing potent anti-breast cancer compounds.

In the present study, we explored the potential of coumarin-based compounds, known for their potent anticancer properties, by designing and synthesizing a novel category of 8-methoxycoumarin-3-carboxamides. Our aim was to investigate their antiproliferative activity against liver cancer cells. Toward this, we developed a versatile synthetic approach to produce a series of 8-methoxycoumarin-3-carboxamide analogues with meticulous structural features. Assessment of their antiproliferative activity demonstrated their significant inhibitory effects on the growth of HepG2 cells, a widely studied liver cancer cell line. Among screened compounds, compound 5 exhibited the most potent antiproliferative activity among the screened compounds (IC₅₀ = 0.9 µM), outperforming the anticancer drug staurosporine (IC₅₀ = 8.4 µM), while showing minimal impact on normal cells. The flow cytometric analysis revealed that compound 5 induces cell cycle arrest during the G1/S phase and triggers apoptosis in HepG2 cells by increasing the percentage of cells arrested in the G2/M and pre-G1 phases. Annexin V-FITC/PI screening further supported the induction of apoptosis without significant necrosis. Further, compound 5 exhibited the ability to activate caspase3/7 protein and substantially inhibited β-tubulin polymerization activity in HepG2 cells. Finally, molecular modelling analysis further affirmed the high binding affinity of compound 5 toward the active cavity of β-tubulin protein, suggesting its mechanistic involvement. Collectively, our findings highlight the therapeutic potential of the presented class of coumarin analogues, especially compound 5, as promising candidates for the development of effective anti-hepatocellular carcinoma agents.

Thiazole and its derivatives have received a lot of attention from researchers due to its wide biological, pharmacological, and anticancer properties. A novel series of 2-[2-[4-Hydroxy-3-substituted benzylidene hydrazinyl]-thiazole-4[5H]-ones (4a–c) and acetoxy derivative (5) were synthesized via using thiosemicarbazones (2a–c). The structure of the thiazole derivatives (4a–c) and 5 in these compounds was confirmed by spectroscopic techniques (IR and NMR), as well as elemental investigations. The synthesized derivatives biological activity was assessed based on their capacity to suppress the growth of the cancer cell lines MCF-7 and HepG2, as well as to halt the cell cycle and trigger apoptosis. Among the synthesized thiazole derivatives, compound 4c was found the most active derivative, with inhibitory concentrations IC₅₀ = 2.57 ± 0.16 and 7.26 ± 0.44 µM in MCF-7 and HepG2, respectively, compared to Staurosporine as the standard drug with IC₅₀ 6.77 ± 0.41 and 8.4 ± 0.51 µM, respectively. Additionally, compound 4c blocked vesicular endothelial growth factor receptor-2 (VEGFR-2), according to our results (IC₅₀ = 0.15 µM), compared to Sorafenib (IC₅₀ = 0.059 µM) as the standard drug. Moreover, compound 4c induced cell cycle arrest at the G1/S phase, increasing the percentage and accumulation of cancer cells (DNA content) in the pre-G1 phase by 37.36% in MCF-7 cancer cells compared to untreated MCF-7 cells at 2.02%. Also, compound 4c increased the percentage of early and late apoptosis from 0.51% and 0.29%, respectively, in the case of the MCF-7 untreated control sample to 22.39% and 9.51%, respectively, in the MCF-7 treated sample. Furthermore, molecular docking studies of compounds 4a–c and 5 were conducted with four key proteins (aromatase, epidermal growth factor receptor (EGFR), cyclin-dependent kinase 2 (CDK2), and B-cell lymphoma 2 (Bcl-2)) that stimulate the growth, proliferation, and development of cancer cells. Compound 4c exhibited good docking scores with a promising and potential binding affinity toward the active site of selected docked proteins. According to these results, compound 4c showed efficient cytotoxic activity against the tested cancer cells.

A new series of hybrid molecules containing cinnamic acid and 2-quinolinone derivatives were designed and synthesized. Their structures were confirmed by ¹H-NMR, ¹³C-NMR and mass analyses. All the synthesized hybrid molecules were assessed for their in vitro antiproliferative activity against more than one cancer cell lines. Compound 3-(3,5-dibromo-7,8-dihydroxy-4-methyl-2-oxoquinolin-1(2H)-ylamino)-3-phenylacrylic acid (5a) with IC₅₀ = 1.89 μM against HCT-116 was proved to the most potent compound in this study, as compared to standard drug staurosporin. DNA flow cytometry assay of compound 5a revealed G2/M phase arrest and pre-G1 apoptosis. Annexin V-FITC showed that the percentage of early and late apoptosis was increased. The results of topoisomerase enzyme inhibition activity showed that the hybrid molecule 5a displays potent inhibitory activity compared with control.