Design, Synthesis, Pharmacological Evaluation of Quinazolin-4(3 H)-Ones Bearing Urea Functionality as Potential VEGFR-2 Inhibitors

Abstract

Background: In response to the urgent need for continuous discovery of new anti-proliferative agents, a new series of quinazoline compounds 5a-r was prepared.

Methods: As a reference, four cancer cell lines-HCT116, HePG2, Hela, and MCF-7-and sorafenib (SOR) were used to assess the novel motifs' in vitro anticancer efficacy. The most cytotoxic compounds were tested in a VEGFR-2 suppressive test and flow cytometric test. Docking analysis was done to the three novel motifs.

Results: Compound 5d showed the best anti-tumor activity of the tested compounds with IC₅₀ 6.09, 2.39, 8.94 and 4.81 μM in succession. In addition, compound 5h revealed a potent anticancer effect against HCT116 and HePG2 with IC₅₀ 5.89 and 6.74 μM, respectively. Also, compound 5p exhibited very strong activity against HCT116, HePG2 & MCF7 with IC₅₀ 8.32, 9.72 and 7.99, respectively. Compound 5p had the highest inhibition against VEGFR-2 with an IC₅₀ of 0.117 μM, in contrast to 0.069 μM for SOR. According to flow cytometric testing, the most effective VEGFR-2 inhibitory agent, 5p, was shown to suppress the G1/S cell population in MCF-7 cells. Docking analysis confirmed that the three novel motifs could bind to the VEGFR-2 enzyme's binding region like the co-crystallized ligand SOR did.

Conclusion: The enzyme inhibitory test of compound 5p showed that it is the most potent hybrid that caused MCF-7 cells to undergo apoptosis and generated a G1/S cell cycle arrest. Confirmation of the obtained results was done with the aid of the docking study, which showed that the three motifs might adhere to the enzyme's major active sites, and the results were in good accordance with the experimental VEGFR-2 inhibitory results. We can conclude that the new quinazoline compounds 5a-r could be used as candidates for development of more efficient anticancer inhibitors.

Keywords: VEGFR-2 inhibitors; apoptosis; cell cycle analysis; molecular docking; quinazolines.

Graphical abstract

Figure 1

Chemical structures of VEGFR-2 inhibitors that the FDA clinically authorized.

Figure 2

A selection of illustrative examples of Quinazolin-4(3H)-ones that have been demonstrated to inhibit VEGFR-2 and the discovery of the desired compounds.

Scheme 1

Synthetic pathway for the target quinazoline compounds 5a-r. Reagents and Conditions: (a) THF, rt, overnight; (b) TEA, ethanol, reflux, 2 hr; (c) K₂CO₃, DMF, 70 °C, 24 hr.

Figure 3

Summary of structure–activity correlation of target quinazoline-4(3H)-ones 5a-r..

Figure 4

The DNA ploidy in MCF-7 cells was examined using flow cytometry following treatment with compound 5p..

Figure 5

Impact of compound 5p on the percentage of Annexin V-FITC positive staining in MCF-7 cells after 24 hours of incubation, with DMSO used as a control. The four stages of cell death are Q1, necrotic cells; Q2, late apoptosis; Q3, living cells; and Q4, early apoptosis.

Figure 6

Molecular docking of the best active compounds in the active site of VEGFR-2 PDB: 4ASD. (a) 3D interaction of compound 5p with the active site of VEFR2 (b) 2D presentation of the interaction of compound 5p. (c) 3D interaction of compound 5h with the active site of VEFR2 (d) 2D presentation of the interaction of compound 5h. (e) 3D interaction of compound 5d with the active site of VEFR2 (f) 2D presentation of the interaction of compound 5d..