Identification of a new family of pyrazolo[3,4-d]pyrimidine derivatives as multitarget Fyn-Blk-Lyn inhibitors active on B- and T-lymphoma cell lines

Abnormal activation of B-cell receptor (BCR) signaling plays a key role in the development of lymphoid malignancies, and could be reverted by the simultaneous inhibition of Lyn, Fyn and Blk, three members of the Src family kinase (SFK). Fyn and Blk are also promising targets for the treatment of some forms of T-cell non-Hodgkin lymphoma which point to the druggability of SFKs for the treatment of these cancers. We recently identified Si308 as a potent Fyn inhibitor, while preliminary data showed that it might also inhibit Lyn and Blk. Here, molecular modelling studies were coupled with enzymatic assays to further investigate the effect of Si308 on Lyn and Blk. A small library of pyrazolo[3,4-d]pyrimidines structurally related to Si308 was synthesized and tested on human lymphoma cell lines. Compound 2h emerged as a new multitarget inhibitor of Lyn, Fyn and Blk endowed with remarkable antiproliferative effects on human B and T lymphoma cell lines. Its favorable ADME properties make the compound suitable for further developments.