Development of a novel thymidylate synthase (TS) inhibitor capable of up-regulating P53 expression and inhibiting angiogenesis in NSCLC.

Introduction: The development of a new type of Thymidylate synthase (TS) inhibitor that could inhibit cancer cells' proliferation and anti-angiogenesis is of great significance for cancer's clinical treatment.

Objectives: Our research hopes to develop a TS inhibitor that is more effective than the current first-line clinical treatment of pemetrexed (PTX) and provide a new reference for the clinical treatment of non-small cell lung cancer (NSCLC).

Methods: We obtained a series of novel TS inhibitors by chemical synthesis. Moreover, TS assay and molecular docking to verify the target compound's inhibitory mode. Use MTT assay, colony-forming assay, flow cytometry, and western blot to verify the compound's inhibitory effect on cancer cell proliferation and its mechanism; and explore the compound's effect on angiogenesis and . Further, explore the hit compound's anti-cancer ability through the xenograft tumor model and the orthotopic cancer murine model.

Results: A series of N-(3-(5-phenyl-1,3,4-oxadiazole-2-yl) phenyl)-2,4-dihydroxypyrimidine-5-sulfamide derivatives were synthesized as TS inhibitors for the first time. All target compounds significantly inhibited hTS enzyme activity and demonstrated significant antitumor activity against five cancer cell lines. Notably, 7 had a high selectivity index (SI) and unique inhibitory effects on eight NSCLC cells. In-depth research indicated that 7 could induce apoptosis by the mitochondrial pathway in A549 and PC-9 cells through the upregulation of wild-type P53 protein expression. Additionally, 7 was shown to inhibit angiogenesis and . studies, compared to PTX, 7 significantly inhibited tumor growth in A549 cell xenografts and had a higher therapeutic index (TGI). Moreover, 7 could prolong the survival of the orthotopic lung cancer murine model more effectively than PTX.

Conclusion: The anti-angiogenic effect of 7 provides a new reference for the development of TS inhibitors and the clinical treatment of NSCLC.