Design, synthesis and biological evaluation of N-phenyl-(2,4-dihydroxypyrimidine-5-sulfonamido)benzoyl hydrazide derivatives as thymidylate synthase (TS) inhibitors and as potential antitumor drugs.

The Inhibition of cellular nucleotide metabolism to promote apoptosis is a key principle of cancer therapy. Thymidylate synthase (TS) is a key rate-limiting enzyme in the initiation of DNA synthesis in cell. Here, we presented two types of thymidylate synthase inhibitors, and, the key pharmacological properties of these two types of thymidylate synthase inhibitor were extracted and combined to design new compounds with inhibitory activity. Therefore, two series of 42 new compounds with the common biological effect of promoting apoptosis are designed and synthesized by combination principle. Most of the compounds had good anti-proliferative activity on A549, OVCAR-3, SGC7901 and MDA-MB-231 cells. The IC50 of compound 10l on A549 cells was 1.26 μM, which was better than that of pemetrexed (PTX, IC50 = 3.31 μM), furthermore, the selection index of compound 10l was higher than PTX. Flow cytometry analysis showed that compound 10l (the apoptosis rate is 39.4%) could induce A549 cell apoptosis and effectively inhibit tumor cell proliferation. Further western blot analysis showed that compound 10l could induce intrinsic apoptosis by activating caspase-3, increasing expression of cleaved caspase-3 and reducing the ratio of bcl-2/bax. All of this makes compound 10l to be a promising compound in future animal tumor models.