Design, synthesis and molecular docking of novel diarylcyclohexenone and diarylindazole derivatives as tubulin polymerization inhibitors

Figures & data

Figure 1. Examples of colchicine binding site inhibitors.

Figure 2. General structures of target compounds.

Scheme 1. Synthesis of compounds 3a,b, 4a,b and 5a–f.

Scheme 2. Synthesis of compounds 6a,b, 7a,b, 8a,b and 9a–f.

Figure 3. Tautomeric forms of 1H-indazol-3-ol.

Table 1. Antiproliferative activity against HCT-116 cell line and MCF-7.

			IC50 (μM)
Compound number	R1	R2	(HCT-116)	(MCF-7)
3a	H	–	55.35	63.39
3b	OCH3	–	28.04	42.07
4a	H	–	19.21	26.70
4b	OCH3	–	6.78	11.40
5a	H	CH3	>100	>100
5b	OCH3	CH3	>100	60.90
5c	H	CH2CH3	>100	>100
5d	OCH3	CH2CH3	>100	>100
5e	H	C6H5	6.71	5.50
5f	OCH3	C6H5	11.05	11.55
6a	H	–	58.46	44.70
6b	OCH3	–	59.80	>100
7a	H	–	30.25	42.75
7b	OCH3	–	88.83	>100
8a	H	–	85.07	58.45
8b	OCH3	–	27.31	60.41
9a	H	CH3	60.60	>100
9b	OCH3	CH3	>100	29.30
9c	H	CH2CH3	>100	>100
9d	OCH3	CH2CH3	34.40	>100
9e	H	C6H5	>100	>100
9f	OCH3	C6H5	78.20	>100
Colchicine	–	–	12.13	9.41

Table 2. Percentage inhibition of tubulin polymerization.

	% Inhibition of tubulin polymerization
Compound	HCT-116	MCF-7
4b	86.96	84.53
5e	89.31	79.72
5f	84.33	86.30
DAMA-colchicine	82.24	86.84

Figure 4. Cell cycle analysis histograms for HCT-116 cells. (A) Control, (B) 4b, (C) 5e and (D) 5f.

Figure 5. Cell cycle analysis histograms for MCF-7 cells. (A) Control, (B) 4b, (C) 5e and (D) 5f.

Table 3. Results of cell cycle analysis in HCT-116 and MCF-7 for compounds 4b, 5e and 5f.

	% of cells in each phase HCT-116			% of cells in each phase MCF-7
	G0-G1	S	G2-M	G0-G1	S	G2-M
Control	67.8	24	8.2	71.3	19.1	9.6
4b	32.8	42	25.2	47.7	24.1	28.2
5e	27.1	35.5	37.4	34.2	27.3	38.5
5f	42.4	24.5	33.1	44.8	21.3	33.9

Table 4. Results of the molecular docking study.

Compound	CDOCKER interaction energy	Type of interaction	Distance	Interacting moiety in the drug	Amino acid involved
DAMA–colchicine	−55.6986	H-Bonding	2.1	SH	C:THR179
		H-Bonding	2.3	Carbonyl of tropone	C:VAL181
		H-Bonding	1.9	OCH3	D:CYS241
(R)-4b	−47.1318	H-Bonding	2.4	OH	C:SER178
		Sigma-Pi	2.8	Pyrazole ring	D:LYS352
		H-Bonding	2.5	NH Pyrazole ring	D:THR353
(S)-4b	−40.6168	H-Bonding	2.3	OH	C:SER178
(R)-5e	−45.1529	H-Bonding	2.1	OH	C:THR179
		Cation-Pi	6.3	Pyrazole ring	D:LYS352
(S)-5e	−48.6425	H-Bonding	2.3	OH	D:ALA250
		Sigma-Pi	2.8	Pyrazole ring	C:LEU248
(R)-5f	−51.0859	H-Bonding	2.1	OH	C:THR179
		H-Bonding	2.7	OCH3	D:CYS241
		Cation-Pi	4.9	Phenyl ring	D:LYS254
		Cation-Pi	6.3	Pyrazole ring	D:LYS352
(S)-5f	−52.3539	H-Bonding	2.3	OCH3	D:CYS241
		Sigma-Pi	2.7	Pyrazole ring	C:LEU248
		H-Bonding	2.2	OH	D:ALA250

Figure 6. 2D interaction diagram of the top docking pose of the R isomer of compound 4b.

Figure 7. Overlay of the top docking poses of R (green) and S (yellow) isomers of 4b in the active site of tubulin (PDB: 1SA0).

Figure 8. 2D interaction diagram of the top docking pose of the R isomer of compound 5e.

Figure 9. 2D interaction diagram of the top docking pose of the R isomer of compound 5f.

Figure 10. 2D interaction diagram of the top docking pose of the S isomer of compound 5e.

Figure 11. Overlay of the top docking poses of R (green), S (yellow) isomers of 5e and DAMA-colchicine (magenta) in the active site of tubulin (PDB: 1SA0).