Biochemistry, pharmacokinetics, and toxicology of a potent and selective DPP8/9 inhibitor
ABSTRACT DPP-IV (EC 18.104.22.168) is a validated drug target for human type II diabetes. DPP-IV inhibitors without DPP8/9 inhibitory activity have been sought because a possible association has been reported between a "DPP8/9 inhibitor" and severe toxicity in animals. However, at present, it is not known whether the observed toxicity is associated with DPP8/9 inhibition, or an off-target effect induced by the compound. We investigated whether the inhibition of DPP8/9 is the cause of the severe toxicity in animals using a very potent and selective DPP8/9 inhibitor with different pharmacophore, 1G244. By Ki measurement, 1G244 is 15- and 8-fold more potent against DPP8 and DPP9, respectively, than the "DPP8/9 inhibitor". Strikingly, the "DPP8/9 inhibitor" does not penetrate the plasma membrane but remains outside the cells, whereas 1G244 readily enters the cells, even at low doses. By repeatedly exposing Sprague-Dawley rats to 1G244 by intravenous injection for a period of 14 days, we observed no significant toxicological symptoms associated with 1G244. Blood and serum chemistry parameters were all within the normal ranges for the treated animals. Because of the high potency, good membrane penetration and adequate tissue distribution of 1G244, the mild symptoms observed are probably associated with DPP8/9 inhibition.
SourceAvailable from: Mymoon Akhter[Show abstract] [Hide abstract]
ABSTRACT: The present study demonstrates and validates the discovery of two novel hydrazine derivatives as selective dipeptidyl peptidase-IV (DPP-IV) inhibitors. Virtual screening (VS) of publicly available databases was performed using virtual screening workflow (VSW) of Schrödinger software against DPP-IV and the most promising hits were selected. Selectivity was further assessed by docking the hits against homology modeled structures of DPP8 and DPP9. Two novel hydrazine derivatives were selected for further studies based on their selectivity threshold. To assess their correct binding modes and stability of their complexes with enzyme, molecular dynamic (MD) simulation studies were performed against the DPP-IV protein and the results revealed that they had a better binding affinity towards DPP-IV as compared to DPP 8 and DPP 9. The binding poses were further validated by docking these ligands with different softwares (Glide and Gold). The proposed binding modes of hydrazines were found to be similar to sitagliptine and alogliptine. Thus, the study reveals the potential of hydrazine derivatives as highly selective DPP-IV inhibitors.Journal of Molecular Modeling 04/2014; 20(4):2118. DOI:10.1007/s00894-014-2118-7 · 1.87 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: Dipeptidyl peptidases (DPPs) 8 and 9 are homologous, cytoplasmic postproline-cutting enzymes, which have similar enzymatic activity and preferred substrates as DPP4. DPP4 is a well-known target for treating diabetes mellitus. With the increased concern of non-selectivity and toxicities caused by DPP4 inhibitors, it is essential to establish new ex vivo system to investigate DPP4 inhibitors' effect on DPP8 and DPP9.Method Here we reported a newly established cell model system by cloning and transfecting human DPP8/9 genes into HEK 293 cells. We then used this model to evaluate the clinically applied DPP4 inhibitors' effect on DPP8/9, by direct enzymatic activity assay. Given the difference of cellular locations between DPP4 and DPP8/9, we also evaluated the influence of these drugs on intracellular DPP8/9 activity and cell viability by extracellular treatment with different inhibitors.ResultsDirect enzymatic activity assay revealed significant and concentration-dependent inhibition effect of vildagliptin, saxagliptin on DPP8/9. Extracellular incubation of DPP8/9 over expressed cells with sitagliptin, vildagliptin, saxagliptin, alogliptin and linagliptin, showed only mild inhibition on DPP8/9. Moreover, all of these drugs showed no significant influence on cell viability.DiscussionOur results demonstrated that the DPP8/9 over-expressing cell model system is a very useful and promising system for investigating the selectivity and associated toxicity of DPP4 inhibitors on DPP8/9.Journal of Pharmacological and Toxicological Methods 11/2014; 71. DOI:10.1016/j.vascn.2014.11.002 · 2.15 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: Introduction: Dipeptidyl-peptidase-4 (DPP-4) inhibitors are a class of anti-hyperglycemic agents with proven efficacy in patients with type 2 diabetes mellitus (T2DM). Areas covered: This review considers the pharmacokinetic profile, adverse effects and drug interactions of DPP-4 inhibitors. DPP-4 inhibitors have certain differences in their structure, metabolism, route of elimination and selectivity for DPP-4 over structurally related enzymes, such as DPP-8/DPP-9. They have a low potential for drug interactions, with the exception of saxagliptin that is largely metabolized by cytochrome CYP3A4/A5. Reports of pancreatitis and pancreatic cancer have raised concerns regarding the safety of DPP-4 inhibitors and are under investigation. Post-marketing surveillance has revealed less common adverse effects, especially a number of skin- and immune-related adverse effects. These issues are covered in the present review. Expert opinion: DPP-4 inhibitors are useful and efficient drugs. DPP-4 inhibitors have similar mechanism of action and similar efficacy. However, DPP-4 inhibitors have certain differences in their pharmacokinetic properties that may be associated with different clinical effects and adverse event profiles. Although clinical trials indicated a favorable safety profile, post-marketing reports revealed certain safety aspects that need further investigation. Certainly, more research is needed to clarify if the differences among DPP-4 inhibitors could lead to a different clinical and safety profile.Expert Opinion on Drug Metabolism & Toxicology 04/2014; 10(10). DOI:10.1517/17425255.2014.907274 · 2.93 Impact Factor