Discovery of a series of novel phenylpiperazine derivatives as EGFR TK inhibitors

Abstract

Human epidermal growth factor receptor (EGFR) is an important drug target that plays a fundamental role in signal transduction pathways in oncology. We report herein the discovery of a novel class of phenylpiperazine derivatives with improved potency toward EGFR. The biological activity of compound 3p as inhibitor of EGFR was further investigated both in vitro and in vivo. Notably, compound 3p exhibited an IC50 in the nanomolar range in A549 cell cultures and induced a cessation of tumor growth with no toxicity, as determined by loss of body weight and death of treated mice. Compoutational docking studies also showed that compound 3p has interaction with EGFR key residues in the active site.

Figure 1. The CDOCKER_INTERACTION_ENERGY (kcal/mol) obtained from the docking study of all synthesized compounds by the CDOCKER protocol (Discovery Studio 3.1, Accelrys, Co. Ltd).

Figure 2. ADMET properties predicted for eighteen novel compounds.

Compounds located inside the innermost oval have the best results. The eight compounds were as follows: 3m, 3r, 3f, 3p, 3c, 3d, 3e, 3i (from top to bottom, from left to right).

Figure 3. HeLa cells were cultured with anticancer and various concentrations of 3p for 24 h.

Cells were stained by Annexin VeFITC/PI and apoptosis was analyzed by flow cytometry. (A) control. (B) 0.03 μM. (C) 0.06 μM. (D) 0.12 μM.

Figure 4. A549 cells were cultured with anticancer and various concentrations of 3p for 24 h.

Cells were stained by Annexin VeFITC/PI and apoptosis was analyzed by flow cytometry. (A) control. (B) 0.03 μM. (C) 0.06 μM. (D) 0.12 μM.

Figure 5. Correlation between the anti-proliferative activity against HeLa and the EGFR inhibitory activity, which indicated that there was a moderate correlation between EGFR inhibition and inhibition of cellular proliferation.

Figure 6. The tumor volumes in mice treated with saline, Erlotinib, compound 3p (20 mg/kg) and compound 3p (40 mg/kg).

Figure 7. The tumor weight in mice treated with saline, Erlotinib, compound 3p (20 mg/kg) and compound 3p (40 mg/kg) at day 14.

Figure 8. The mice weight was examined every other day.

Figure 9

(A) 2D molecular docking model of compound 3p with 1M17. (B) 3D interaction map between compound 3p and 1M17 binding site. (C) 2D diagram of docking structure of compound erlotinib with 1M17. (D) 3D Model of the interaction between compound erlotinib and 1M17 binding site.

Figure 10. 3D-QSAR of designed compounds for EGFR (PDB code: 1M17).

(A) Isosurface of the 3D-QSAR model coefficients on electrostatic potential grids. The blue triangle mesh represents positive electrostatic potential and the red area represents negative electrostatic potential. (B) Isosurface of the 3D-QSAR model coefficients on Van der Waals grids. The green triangle mesh representation indicates positive coefficients; the yellow triangle mesh indicates negative coefficients.

Figure 11. Crystal structure of compound 3m.

(A) Molecular structure of compound 3m with atomic numbering scheme. (B) Crystal packing of the compound 3m.