Identification of Thieno[3,2-d]pyrimidine Derivatives as Dual Inhibitors of Focal Adhesion Kinase and FMS-like Tyrosine Kinase 3

Abstract

Focal adhesion kinase (FAK) is overexpressed in highly invasive and metastatic cancers. To identify novel FAK inhibitors, we designed and synthesized various thieno­[3,2-d]­pyrimidine derivatives. An intensive structure–activity relationship (SAR) study led to the identification of 26 as a lead. Moreover, 26, a multitargeted kinase inhibitor, possesses excellent potencies against FLT3 mutants as well as FAK. Gratifyingly, 26 remarkably inhibits recalcitrant FLT3 mutants, including F691L, that cause drug resistance. Importantly, 26 is superior to PF-562271 in terms of apoptosis induction, anchorage-independent growth inhibition, and tumor burden reduction in the MDA-MB-231 xenograft mouse model. Also, 26 causes regression of tumor growth in the MV4–11 xenograft mouse model, indicating that it could be effective against acute myeloid leukemia (AML). Finally, in an orthotopic mouse model using MDA-MB-231, 26 remarkably prevents metastasis of orthotopic tumors to lymph nodes. Taken together, the results indicate that 26 possesses potential therapeutic value against highly invasive cancers and relapsed AML.

Molecular Docking, Molecular Dynamics Simulations, and Free Energy Calculation Insights into the Binding Mechanism between VS-4718 and Focal Adhesion Kinase

“…In such cases, the side chain of I428 is responsible for the interaction with the methoxybenzene ring, as observed from the distance and angle of the interacting structure (Figure S32). However, the CD1 and CG1 atoms of the I418 side chain exhibit angles >90° with the methoxybenzene ring, and as previously reported, this ring could be modified with aliphatic groups, as observed for the thieno­[3,2- d ]­pyrimidine derivatives . The methoxy group points toward the hinge loop of FAK, while in contrast, the methyl group of dasatinib has been reported to result in the opposite orientation .…”

“…Furthermore, it was determined that two of the hydrogen bonds formed between FAK and VS-4718 were located within the diamino-pyridine ring; these interactions represent the universal hydrogen bonds that are commonly found for FAK inhibitors 30 , 31 , 117 and other protein kinase inhibitors. 118 , 119 Moreover, the 7 H -pyrrolo[2,3- d ]pyrimidine, 120 , 121 diamino-pyrimidine, 58 , 122 − 124 and thieno[3,2- d ]pyrimidine 125 rings also contribute to the binding model in a manner similar to the indazole ring, thereby indicating that the indazole ring can be replaced with a pyrazole or pyridine ring.…”

“…However, the CD1 and CG1 atoms of the I418 side chain exhibit angles >90° with the methoxybenzene ring, and as previously reported, this ring could be modified with aliphatic groups, as observed for the thieno[3,2- d ]pyrimidine derivatives. 125 The methoxy group points toward the hinge loop of FAK, while in contrast, the methyl group of dasatinib has been reported to result in the opposite orientation. 105 It would also be expected that if the pyridine and methoxybenzene rings were to be linked by a five- or six-membered ring system, favorable hydrophobic interaction would form with the CD1 or CG1 atoms of the I428 residue to increase the binding affinity.…”

“…The oxygen atom of the C502 residue also took part in hydrogen bonding with the N5 atom of VS-4718, acting as an acceptor, with occupancies of 96.53 and 66.64% being determined for the FAK-II-1 and FAK-II-4 systems, respectively. Furthermore, it was determined that two of the hydrogen bonds formed between FAK and VS-4718 were located within the diamino-pyridine ring; these interactions represent the universal hydrogen bonds that are commonly found for FAK inhibitors ,, and other protein kinase inhibitors. , Moreover, the 7 H -pyrrolo­[2,3- d ]­pyrimidine, , diamino-pyrimidine, ,− and thieno­[3,2- d ]­pyrimidine rings also contribute to the binding model in a manner similar to the indazole ring, thereby indicating that the indazole ring can be replaced with a pyrazole or pyridine ring.…”

The Development of FAK Inhibitors: A Five-Year Update

“…Finally, 23 significantly prevented metastasis of orthotopic MDA-MB-231 cell tumor. All these biological data support the therapeutic potential of this thieno[3,2- d ]pyrimidine for the treatment of highly invasive cancers, including drug-resistant AML harboring recalcitrant FLT3 and/or FAK mutants [ 55 ].…”