Synthesis, biological evaluation, and molecular docking of new series of antitumor and apoptosis inducers designed as VEGFR-2 inhibitors

Abstract

Based on quinazoline, quinoxaline, and nitrobenzene scaffolds and on pharmacophoric features of VEGFR-2 inhibitors, 17 novel compounds were designed and synthesised. VEGFR-2 IC₅₀ values ranged from 60.00 to 123.85 nM for the new derivatives compared to 54.00 nM for sorafenib. Compounds 15_a, 15_b, and 15_d showed IC₅₀ from 17.39 to 47.10 µM against human cancer cell lines; hepatocellular carcinoma (HepG2), prostate cancer (PC3), and breast cancer (MCF-7). Meanwhile, the first in terms of VEGFR-2 inhibition was compound 15_d which came second with regard to antitumor assay with IC₅₀ = 24.10, 40.90, and 33.40 µM against aforementioned cell lines, respectively. Furthermore, Compound 15_d increased apoptosis rate of HepG2 from 1.20 to 12.46% as it significantly increased levels of Caspase-3, BAX, and P53 from 49.6274, 40.62, and 42.84 to 561.427, 395.04, and 415.027 pg/mL, respectively. Moreover, 15_d showed IC₅₀ of 253 and 381 nM against HER2 and FGFR, respectively.

Keywords: Anticancer; VEGFR-2; apoptosis; multi-kinase; pharmacophoric features.

Figure 1.

Structures of some reported VEGFR-2 kinase inhibitors.

Figure 2.

Sorafenib as a model for pharmacophoric features of type II VEGFR-2 kinase inhibitors.

Figure 3.

Summary for the rationale of molecular design showing that, the target compounds fulfilled the pharmacophoric features of VEGFR-2 inhibitors.

Scheme 1.

General procedure for preparation of intermediates 9a,b and 10a–d; Reagents and conditions: (a) phenyl or butylisocyanate, absolute ethanol, reflux, 2 h. (b) DCM, ClCOOEt, Et3N, ice salt bath.

Scheme 2.

General procedure for preparation of final compounds 14a&b and 15a–d; Reagents and conditions: (a) urea, fusion, 4 h. (b) POCl₃, Et₃N, reflux, 6 h. (c) K₂CO₃, isopropanol, reflux, 1 h.

Scheme 3.

General procedure for synthesis of final compounds 19a&b and 20a–d; Reagents and conditions: (a) oxalic acid, HCl, H₂O, reflux. (b) POCl₃, DMF, reflux, 3 h. (c) K₂CO₃, isopropanol, reflux, 3 h.

Scheme 4.

General procedure for synthesis of final compounds 22a&b and 23a–d; Reagents and conditions: (a) K₂CO₃, isopropanol, reflux, 2h.

Figure 4.

(A) HepG-2 cells distribution upon treatment with compound 15_d. (B) Percentages of cell cycle phases of HePG2 treated with 15_d in comparison with control.

Figure 5.

(A). Histogram for the effect of compound 15_d on both apoptosis and necrosis of HepG2 cells. (B) Column chart representing the effect of compound 15_d on both apoptosis and necrosis of HepG2 cells.

Figure 6.

The effect of compound 15d on apoptotic markers of HepG2 cells.

Figure 7.

Overlay of the co-crystallized ligand (magenta) and the redocking one (turquoise) of sorafenib into VEGFR-2 kinase active site.

Figure 8.

(A) 3D of sorafenib binding mode. (B) 2D of sorafenib binding mode.

Figure 9.

(A) 3D of compound 14_a binding pattern (B) 2D of compound 14_a binding pattern (C) Superimposing 14_a (turquoise) and sorafenib (magenta).

Figure 10.

(A) 3D of 15_c binding pattern. (B) 2D of 15_c binding pattern. (C) Superimposing 15_c (turquoise) and sorafenib (magenta).

Figure 11.

(A) 3D of compound 15_d binding pattern (B) 2D of compound 15_d binding pattern (C) Overlay of 15_d (turquoise) and sorafenib (magenta).