Studies on the ATP Binding Site of Fyn Kinase for the Identification of New Inhibitors and Their Evaluation as Potential Agents against Tauopathies and Tumors

Abstract

Fyn is a member of the Src-family of nonreceptor protein-tyrosine kinases. Its abnormal activity has been shown to be related to various human cancers as well as to severe pathologies, such as Alzheimer's and Parkinson's diseases. Herein, a structure-based drug design protocol was employed aimed at identifying novel Fyn inhibitors. Two hits from commercial sources (1, 2) were found active against Fyn with K(i) of about 2 μM, while derivative 4a, derived from our internal library, showed a K(i) of 0.9 μM. A hit-to-lead optimization effort was then initiated on derivative 4a to improve its potency. Slightly modifications rapidly determine an increase in the binding affinity, with the best inhibitors 4c and 4d having K(i)s of 70 and 95 nM, respectively. Both compounds were found able to inhibit the phosphorylation of the protein Tau in an Alzheimer's model cell line and showed antiproliferative activities against different cancer cell lines.

A Pyrazolo[3,4-d]pyrimidine Compound Reduces Cell Viability and Induces Apoptosis in Different Hematological Malignancies

“…In agreement with our data, a lot of recent studies showed that the use of TKIs, especially against Btk, Syk, and Lyn, is a promising new strategy for targeted treatment of B-cell lymphoid malignancies (Robak and Robak, 2012). Furthermore, these data on Jurl-MK1 confirmed our previously results obtained in K562 CML cell line (Tintori et al, 2015). …”

“…Since we previously observed, by in vitro enzymatic assay, that 4c compound inhibited different Src kinases, in particular Fyn with IC 50 = 0.07 μM (Tintori et al, 2015), we verified the presence of Fyn protein in our HM cell lines. Interestingly, we observed that its expression is higher and variable in all cell lines compared to HD-PBMCs.…”

“…In particular, we have previously demonstrated that 4c pyrazolo[3,4- d ]pyrimidine compound, is able to inhibit Fyn kinase and to induce apoptosis in cells derived from NK leukemia and from CML (Tintori et al, 2015; Laurenzana et al, 2016). …”

“…Moreover, we demonstrated that 4c pyrazolo[3,4- d ]pyrimidine compound was able to reduce cell viability, induce apoptosis and cell cycle arrest in a rare natural killer (NK) cell leukemia and in CML. In particular, it reduced phosphorylation of Fyn kinase in these neoplasms (Tintori et al, 2015; Laurenzana et al, 2016). …”

Synthesis and in vitro antibacterial evaluation of 6-substituted 4-amino-pyrazolo[3,4-d]pyrimidines

“…One of the common starting materials in the synthesis of pyrazolo [3,4-d]pyrimidines is 5-amino-4-cyanopyrazoles (Quintela et al 2001;Song et al 2011;Rahmouni et al 2014;Agrebi et al 2014;Tintori et al 2015;Siebeneicher et al 2016). Reaction of these compounds with nitriles under various conditions is reported (Hanefeld et al 1996;Smith et al 2007;Davoodnia et al 2012).…”