Molecular Modeling Studies of Trisubstituted Thiazoles as Cdc7 Kinase Inhibitors through 3D-QSAR and Molecular Docking Simulation

A Structural and In Silico Investigation of Potential CDC7 Kinase Enzyme Inhibitors

A crucial role in the regulation of DNA replication is played by the highly conserved CDC kinase. The CDC7 kinase could serve as a target for therapeutic intervention in cancer. The primary heterocyclic substance is pyrazole, and its derivatives offer great potential as treatments for cancer cell lines. Here, we synthesized the two pyrazole derivatives: 4-(2-(4-chlorophenyl)hydrazinyl)-5-methyl-2-tosyl-1H-pyrazol-3(2H)-one (PYRA-1) and 4-(2-(2,4-difluorophenyl)hydrazinyl)-5-methyl-2-tosyl-1H-pyrazol-3(2H)-one (PYRA-2). The structural confirmation of both the compounds at the three-dimensional level is characterized using single crystal X-ray diffraction and density functional theory. Furthermore, the in silico chemical biological properties were derived using molecular docking and molecular dynamics (MD) simulations. PYRA-1 and PYRA-2 crystallize in the P-1 (a = 8.184(9), b = 14.251(13), c = 15.601(15), α = 91.57(8), β = 97.48(9), 92.67(9), V = 1801.1(3) 3, and Z = 2) and P21/n (a = 14.8648(8), b = 8.5998(4), c = 15.5586(8), β = 116.47(7), V = 1780.4(19) 3, and Z = 4), space groups, respectively. In both PYRA-1 and PYRA-2 compounds, C-H···O intermolecular connections are common to stabilize the crystal structure. In addition, short intermolecular interactions stabilizes with C-H···π and π-π stacking. Crystal packing analysis was quantified using Hirshfeld surface analysis resulting in C···H, O···H, and H···H contacts in PYRA-1 exhibiting more contribution than in PYRA-2. The conformational stabilities of the molecules are same in the gas and liquid phases (water and DMSO). The docking scores measured for PYRA-1 and PYRA-2 with CDC7 kinase complexes are -5.421 and -5.884 kcal/mol, respectively. The MD simulations show that PYRA-2 is a more potential inhibitor than PYRA-1 against CDC7 kinase.

Receptor-guided 3D-QSAR studies, molecular dynamics simulation and free energy calculations of Btk kinase inhibitors

BACKGROUND

Bruton tyrosine kinase (Btk) plays an important role in B-cell development, differentiation, and signaling. It is also found be in involved in male immunodeficiency disease such as X-linked agammaglobulinemia (XLA). Btk is considered as a potential therapeutic target for treating autoimmune diseases and hematological malignancies.

RESULTS

In this work, a combined molecular modeling study was performed on a series of thieno [3,2-c] pyridine-4-amine derivatives as Btk inhibitors. Receptor-guided COMFA (q 2 = 0.574, NOC = 3, r 2 = 0.924) and COMSIA (q 2 = 0.646, NOC = 6, r 2 = 0.971) models were generated based on the docked conformation of the most active compound 26. All the developed models were tested for robustness using various validation techniques. Furthermore, a 5-ns molecular dynamics (MD) simulation and binding free energy calculations were carried out to determine the binding modes of the inhibitors and to identify crucial interacting residues. The rationality and stability of molecular docking and 3D-QSAR results were validated by MD simulation. The binding free energies calculated by the MM/PBSA method showed the importance of the van der Waals interaction.

CONCLUSIONS

A good correlation between the MD results, docking studies, and the contour map analysis were observed. The study has identified the key amino acid residues in Btk binding pocket. The results from this study can provide some insights into the development of potent, novel Btk inhibitors.