Reactive Oxygen Species (ROS)-Sensitive Prodrugs of the Tyrosine Kinase Inhibitor Crizotinib

Abstract

Tyrosine kinase inhibitors revolutionized cancer therapy but still evoke strong adverse effects that can dramatically reduce patients’ quality of life. One possibility to enhance drug safety is the exploitation of prodrug strategies to selectively activate a drug inside the tumor tissue. In this study, we designed a prodrug strategy for the approved c-MET, ALK, and ROS1 tyrosine kinase inhibitor crizotinib. Therefore, a boronic-acid trigger moiety was attached to the 2-aminopyridine group of crizotinib, which is a crucial position for target kinase binding. The influence of the modifications on the c-MET- and ALK-binding ability was investigated by docking studies, and the strongly reduced interactions could be confirmed by cell-free kinase inhibition assay. Furthermore, the newly synthesized compounds were tested for their activation behavior with H2O2 and their stability in cell culture medium and serum. Finally, the biological activity of the prodrugs was investigated in three cancer cell lines and revealed a good correlation between activity and intrinsic H2O2 levels of the cells for prodrug A. Furthermore, the activity of this prodrug was distinctly reduced in a non-malignant, c-MET expressing human lung fibroblast (HLF) cell line.

Recent Advances in Hydrogen Peroxide Responsive Organoborons for Biological and Biomedical Applications

“…Reaction of prodrugs 91 and 92 (100 μM) with 500 μM H 2 O 2 in a mixture of DMSO in PBS buffer was complete within ∼250 min releasing the active drug 5FU [151] . The reaction of 93 with ten equivalents of H 2 O 2 released ∼50 % of the active crizotinib after 10 min, and ∼75 % after 1 h [154] . Treatment of prodrugs 98 and 99 a,b (50 μM) with 0.5 mM H 2 O 2 produced >95 % oxidation products in less than 3 h [168] .…”

“…Crizotinib consists of an aminopyridine moiety for adenine binding, methyl group of benzyloxy for N‐lobe pocket binding and a dichloro‐substituted benzene ring for inhibiting the tyrosine kinase receptor (c‐MET) [152,153] . Recently, a ROS‐responsive prodrug 93 has been developed to reduce the side effects of crizotinib by masking the target kinase binding site, the 2‐aminopyridine of crizotinib, with a boronic acid trigger moiety [154] . A cell‐free kinase inhibition assay indicated that 93 showed a distinct reduction in activity against crizotinib's targets ALK and c‐MET.…”

“…[152,153] Recently, a ROS-responsive prodrug 93 has been developed to reduce the side effects of crizotinib by masking the target kinase binding site, the 2-aminopyridine of crizotinib, with a boronic acid trigger moiety. [154] A cell-free kinase inhibition assay indicated that 93 showed a distinct reduction in activity Scheme 21. H 2 O 2 activatable prodrugs of gemcitabine (90), 5-fluorouracil (91 and 92), crizotinib (93) and paclitaxel (94).…”

Boronic Acids and Their Derivatives in Medicinal Chemistry: Synthesis and Biological Applications

“…When present in high levels, which occurs in malignant cells, H 2 O 2 oxidizes the boronic acid moiety and allows the selective release of crizotinib. It was also proved that, in case of prodrug 51 , more than half of the prodrug remains intact in biological conditions, therefore not releasing crizotinib [ 53 ].…”

“…The 2-aminopyridine of crizotinib ( 50 ) is modified ( Scheme 11 ): First occurred a protection of the piperidine nitrogen with a tert-butyloxycarbonyl (Boc) group, followed by selective functionalization of the 2-aminopyridine. In the case of prodrug 51 , the moiety was introduced via carbamate, while in prodrug 52 was via alkylation, using a reductive amination approach [ 53 ].…”