Discovery of DB18, a potent inhibitor of CLK kinases with a high selectivity against DYRK1A kinase

Abstract

We describe in this paper the synthesis of a novel series of anilino-2-quinazoline derivatives. These compounds have been screened against a panel of eight mammalian kinases and in parallel they were tested for cytotoxicity on a representative panel of seven cancer cell lines. One of them (DB18) has been found to be a very potent inhibitor of human "CDC2-like kinases" CLK1, CLK2 and CLK4, with IC 50 values in the 10-30 nM range. Interestingly, this molecule is inactive at 100M on the closely related "dualspecificity tyrosine-regulated kinase 1A" (DYRK1A). Extensive molecular simulation studies have been performed on the relevant kinases to explain the strong affinity of this molecule on CLKs, as well as its selectivity against DYRK1A.

Development of Cdc2-like Kinase 2 Inhibitors: Achievements and Future Directions

“…CLKs phosphorylate both serine–proline dipeptides and the RS domain, but SRPKs are specific to the RS domain. , CLK2 phosphorylates the substrates PTPN1, SRSF1, and SRSF3 . Furthermore, the four isoforms of CLKs also exhibit minor substrate specificities in phosphorylating SR proteins. ,− Nevertheless, CLK2 can regulate alternative splicing and modulate expression of Wnt-related proteins for the treatment of degenerative diseases.…”

“…CLK2 inhibitors were first described in 2009; in recent years, attempts have been made to discover and investigate potential selective CLK2 inhibitors. ,,, Although several CLK2 inhibitors have been reported in literature and patents, only a few compounds have entered clinical trials. To the best of our knowledge, two CLK2 inhibitors and three pan-CLK inhibitors are currently under investigation in clinical trials for the treatment of degenerative disease and tumors.…”

“…Quinazoline is one of the most widespread core structures found in various kinase inhibitors . In 2020, Brahmaiah et al demonstrated quinazoline derivative 21 (DB18, CLK2 IC 50 = 27 nM, Figure B) as a CLK1, CLK2, and CLK4 inhibitor using in silico screening . It was observed that compound 21 exhibited selective cytotoxicity for PC3 (IC 50 = 7 μM) and MCF7 (IC 50 = 4 μM).…”

“…78 It is suitable for HTS and offers advantages such as low loss of protein and high temperature ranges. 42 The results of this method are easily 33,63,66,79 Although several CLK2 inhibitors have been reported in literature and patents, only a few compounds have entered clinical trials. To the best of our knowledge, two CLK2 inhibitors and three pan-CLK inhibitors are currently under investigation in clinical trials for the treatment of degenerative disease and tumors.…”

Synthesis and Cytotoxic Studies of Quinazoline-Triazole Hybrid Aza Heterocycles

“…Our research group has studied new series of triazolylquinazolines-2-triazolylalkoxyquinazolines and 8-triazolylalkoxyquinazolines as MmCLK1, CLK1 kinases inhibitors. Most of those compounds did not show any significant cytotoxicity against HuH7, CaCo-2, MDA-MB231, HCT116, PC3, NCI-H727, and MCF7 cancer cell lines [14,15]. Up to date, cytotoxicity of quinazoline-triazole hybrids has not been tested against brain cancer cell lines, for which reason we have carried out synthesis of such compounds and tested their certain activity.…”