Mouse anti-Human DPP8 monoclonal antibody, clone 2C21

Dipeptide-derived compounds, bearing various P2 residues and a diaryl pyrrolidin-2-yl phosphonate at the PI position, were evaluated as dipeptidyl peptidase 8 (DPP8) inhibitors. With these products, irreversible inhibition of DPP8 was observed. To obtain inhibitors with an improved activity and selectivity profile, a set of selected analogues containing a diaryl isoindolin-1-ylphosphonate at P1 was synthesized and evaluated. Within this latter series, compound 2e was shown to be a potent, irreversible inhibitor of DPP8, demonstrating very low affinity for DPP IV and DPP II.

In this report we demonstrate expression of dipeptidyl peptidase(DPP)-IV enzymatic activity bearing molecules in primary cell cultures derived from human glioblastomas. We show that in additon to the canonical DPP-IV/CD26 (EC 3.4.14.5). fibroblast activation protein. DPP8 and DPP9 may participate on the DPP-IV enzymatic activity in primary cell cultures. High DPP-IV enzymatic activity was associated with slower cell growth at an early stage of cultivation. Additionally, in 3 out of 4 primary cell cultures propagated for up to 20 pages, there was a negative relation between the cell growth and DPP-IV enzymatic activity in individual passages. DPP-IV/CD26 overexpression in transfected glioma cell lines U373 and T98G also led to decreased cell growth, a decrease of cells in S phase and a G2/M cell cycle block. In conclusion, DPP-IV participates on the regulation of glioma cell growth.