FMS-like tyrosine kinase 3 (FLT3) inhibitors: Molecular docking and experimental studies
Baratali Mashkani1, Mohammad Hossein Tanipour2, Mohammad Saadatmandzadeh3
1Department of Medical Biochemistry, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran; School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW 2308, Australia.
Abstract:
Activating mutations in FMS-like tyrosine kinase 3 (FLT3) occur in 25% of acute lymphoid and 30% of acute myeloid leukaemia cases. Therefore, FLT3 is a potential therapeutic target for small molecule kinase inhibitors. In this study, protein-ligand interactions between FLT3 and kinase inhibitors (CEP701, PKC412, sunitinib, imatinib and dasatinib) were obtained through homology modelling and molecular docking. A cellular system for experimental testing of the inhibitors was also established by expressing wildtype and internal tandem duplication mutant FLT3 (FLT3-WT and FLT3-ITD) in FDC-P1 cells. Imatinib and dasatinib could not be docked into any of the FLT3 models, consistent with their lack of activity in the experimental assays. CEP701, PKC412 and sunitinib interacted with the ATP-binding pocket of FLT3, forming H-bonds with Cys694 and Glu692. Based on the EC50 values in the cell proliferation assay, CEP701 was the most potent inhibitor; sunitinib and PKC412 were ranked second and third, respectively. Sunitinib was the most selective inhibitor, followed by PKC421 and CEP701. The potency of sunitinib and to a lesser extent CEP701 in inhibition of FLT3 autophosphorylation was lower than the cell proliferation inhibition, indicating that inhibition of FLT3 downstream proteins may contribute to the cellular effects. It was shown in this study that the docking procedure was able to differentiate FLT3 inhibitors from ineffective compounds. Additionally, interaction with the phosphate binding region in the ATP-binding pocket increased potency at the cost of selectivity. These findings can be applied in designing highly effective and selective inhibitors for FLT3 and other related kinases.
Insights
Activating mutations in FMS-like tyrosine kinase 3 (FLT3) are common in leukemia. Molecular docking identified key interactions for potent and selective small molecule kinase inhibitors, aiding drug design.
Area of Science:
- Biochemistry
- Pharmacology
- Computational Biology
Background:
- Activating mutations in FMS-like tyrosine kinase 3 (FLT3) are prevalent in acute lymphoid and myeloid leukemias.
- FLT3 represents a significant therapeutic target for small molecule kinase inhibitors.
Purpose of the Study:
- To investigate protein-ligand interactions between FLT3 and various kinase inhibitors using computational and experimental methods.
- To evaluate the potency and selectivity of identified FLT3 inhibitors.
Main Methods:
- Homology modeling and molecular docking were employed to predict interactions between FLT3 and inhibitors (CEP701, PKC412, sunitinib, imatinib, dasatinib).
- A cellular system expressing wildtype and mutant FLT3 (FLT3-WT, FLT3-ITD) was established for experimental validation.
- Inhibitor activity was assessed through cell proliferation assays and FLT3 autophosphorylation inhibition.
Main Results:
- Imatinib and dasatinib showed no interaction with FLT3 models and lacked experimental activity.
- CEP701, PKC412, and sunitinib interacted with the FLT3 ATP-binding pocket, forming hydrogen bonds with key residues.
- CEP701 demonstrated the highest potency, followed by sunitinib and PKC412; sunitinib was the most selective inhibitor.
Conclusions:
- Molecular docking effectively differentiated active FLT3 inhibitors from inactive compounds.
- Interaction with the ATP-binding pocket's phosphate region enhances potency but may reduce selectivity.
- Findings provide a basis for designing more effective and selective FLT3 inhibitors for leukemia treatment.
