Seliciclib (Roscovitine) displays high efficiency and high selectivity towards some cyclin-dependent kinases. The kinase specificity of Seliciclib is investigated with 25 highly purified kinases (including protein kinase A, G and C isoforms, myosin light-chain kinase, casein kinase 2, IR tyrosine kinase, c-src, v-abl). Most kinases are not significantly inhibited by Seliciclib (Roscovitine). Cdc2, Cdk2, and Cdk5 only are substantially inhibited (IC50 values of 0.65, 0.7, and 0.2 μM, respectively). Cdk4k and Cdk6 are very poorly inhibited by Seliciclib (Roscovitine) (IC50>100 μM). Extracellular regulated kinases erk1 and erk2 are inhibited with an IC50 of 34 μM and 14 μM, respectively. Seliciclib (Roscovitine) inhibits the proliferation of mammalian cell lines with an average IC50 of 16 μM. Seliciclib decreases the level of CDK5 and p35 with upregulation of E-cadherin, but downregulation of Vimentin and Collagen IV. Moreover, Seliciclib (Roscovitine) inhibits the ability of high glucose cultured NRK52E cells to migrate and invade.