Pyrido[2,3-d]pyrimidine-2,4(1H,3H)-dione derivatives as RAF-MEK-ERK pathway signaling pathway blockers: Synthesis, cytotoxic activity, mechanistic investigation and structure-activity relationships

The constitutive activation of ERK1/2 (RAF-MEK-ERK) signaling pathway has been widely observed in many types of tumors, and the blockade of ERK1/2 signaling pathway has been proved to reduce tumor growth. Therefore, ERK1/2 signaling pathway has become an interesting therapeutic target for cancer therapy. Despite the successful development of BRAF and MEK inhibitors in clinic treatment, resistance often appears to re -enhance ERK1/2 signaling. Here we report the design, synthesis, biological activity of a series of novel pyrido [2,3-d]pyrimidine-2,4(1H,3H)-dione derivatives based on compound 1. Among them, the target compound N-(3- chlorophenyl)-2-((1,3-dimethyl-7-(4-methylpiperazin-1-yl)-2,4-dioxo-1,2,3,4-tetrahydropyrido[2,3-d]pyrimidin-5-yl)amino)acetamide (14m) exhibited excellent antiproliferative activity towards MCF-7, A375, SK-MEL-2 and SK-HEP-1 cells, with low cytotoxicity in C28/I2 cells. Tumor spheroid assay demonstrated the superior potency of 14m in inhibiting the growth of SK-HEP-1 spheroidal models. The mechanism of 14m to induce cancer cell death was shown to suppress cell migrations, induce cell apoptosis, decrease the levels of phosphorylated ERK and MEK in a dose-dependent manner and increase ROS production.

Automated summary

Constitutive activation of the ERK1/2 signaling pathway is commonly observed in various types of tumors. In this study, we report the design and synthesis of novel pyrido[2,3-d]pyrimidine-2,4(1H,3H)-dione derivatives based on compound 1. Among them, compound 14m exhibited excellent antiproliferative activity and demonstrated promising results in inhibiting tumor growth in spheroidal models. Mechanistically, compound 14m suppressed cell migration, induced apoptosis, and modulated the phosphorylation levels of ERK and MEK in a dose-dependent manner.