Small‐Molecule Inhibitors of the Tumor Suppressor Fhit

Abstract

The tumor suppressor Fhit and its substrate diadenosine triphosphate (Ap A) are important factors in cancer development and progression. Fhit has Ap A hydrolase activity and cleaves Ap A into adenosine monophosphate (AMP) and adenosine diphosphate (ADP); this is believed to terminate Fhit-mediated signaling. How the catalytic activity of Fhit is regulated and how the Fhit⋅Ap A complex might exert its growth-suppressive function remain to be discovered. Small-molecule inhibitors of the enzymatic activity of Fhit would provide valuable tools for the elucidation of its tumor-suppressive functions. Here we describe the development of a high-throughput screen for the identification of such small-molecule inhibitors of Fhit. Two clusters of inhibitors that decreased the activity of Fhit by at least 90 % were identified. Several derivatives were synthesized and exhibited in vitro IC values in the nanomolar range.

Synthesis of Trifluoromethylated Purine Ribonucleotides and Their Evaluation as 19F NMR Probes

“…These include assays involving radioactivity, 49 , 50 fluorogenic probes, 31 malachite green (MG) assay, 51 (2) and fluorescent resonance energy transfer (FRET) probes. 52 , 53 (3) However, these assays have some limitations such as discontinuity, susceptibility to interference from UV–vis absorbing and emitting inhibitors, or high structural complexity of the probes. Thus, methods that enable robust and straightforward real-time monitoring of activity of these enzymes are still desired.…”

“… 54 hFhit is considered to be a tumor suppressor, and its function has been linked to substrate binding. Hence, efforts have been made to identify hFhit inhibitors 52 , 53 but not by 19 F NMR spectroscopy. We verified that hFhit accepts the bis(trifluoromethylated) Ap 3 A analog 25 as a substrate.…”

“…54 hFhit is considered to be a tumor suppressor, and its function has been linked to substrate binding. Hence, efforts have been made to identify hFhit inhibitors 52,53 but not by 19 S1B-D). Despite the small differences in chemical shifts from the substrate, it was convenient to monitor the reaction progress by 19 F NMR and observe the inhibitory effect of a previously identified compound 53 (Figure 1A).…”

Small Molecules: Therapeutic Application in Neuropsychiatric and Neurodegenerative Disorders

“…Indeed, in a large variety of pathological conditions, several molecular alterations, which do not generally occur in physiological states, are detectable and mainly regard the increased production of free radicals, pH alterations and impaired generation of some specific biomolecules [ 2 ]. In recent years, an increasing number of studies focused on the potential therapeutic use of small agents with strong biological properties have been published [ 3 ], but, so far, most of the reports on this subject have mainly regarded proliferative or infectious diseases [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ].…”

Tanshinones induce tumor cell apoptosis via directly targeting FHIT

“…Among these, suramin and non-cleavable ApnA analogues have been presented over a decade which inhibit FHIT without selectivity compared to other different classes of enzymes 17 , 18 . During past year, a high-throughput screening assay of Förster Resonance Energy Transfer (FRET) was developed to discover potent small molecule inhibitors of FHIT based on a doubly labeled Ap3A probe 19 , and several inhibitors with methylpyrazolo-motive or indino-motive were identified to block FHIT activity 20 , but those inhibitors were not applied to cellular content, potentially due to the difference of protein between purified protein and cellular protein with extensive post-translational modification and protein–protein interactions 21 .…”