Synthesis of certain benzothieno[3,2-d]pyrimidine derivatives as a selective SIRT2 inhibitors

A series of new benzothieno[3,2-d]pyrimidine derivatives were designed and synthesized. The National Cancer Institute (NCI, USA) evaluated all synthesized compounds against 60 human tumor cell lines. Most of the compounds showed good cytotoxicity against MCF-7 breast cancer cell line and UO-31 renal cancer cell line (growth inhibitory range: 17.88%-68.65%). IC₅₀ of twelve most active compounds was determined against MCF-7 and UO-31 cell lines. Compounds 7, 10, 13, 16 and 17 proved a prominent anticancer activity against tested cell lines (IC₅₀ range 0.23-26.25 μg/mL). IC₅₀ against SIRT2 enzyme was evaluated for the most active compounds to explore the mechanism of antiproliferative activity. The best activity was displayed by compound 7 (IC₅₀ = 2.10 μg/mL), which is 6.6 more potent than cambinol as a reference. Moreover, compound 7 displayed high selectivity against SIRT1 and SIRT2 over SIRT3 in the selectivity studies and displayed twice activity of cambinol in hyperacetylation of α-tubulin protein with IC₅₀ = 32.05 μg/mL. Molecular docking study of the synthesized compounds into SIRT2 active site was performed to rationalize the remarkable SIRT2 inhibitory activity.