Rational Design, Synthesis, and Biological Evaluation of Novel S1PR2 Antagonists for Reversing 5-FU-Resistance in Colorectal Cancer

Abstract

Resistance to 5-FU reduces its clinical efficacy for the treatment of colorectal cancer. Sphingosine-1-phosphate receptor 2 (S1PR2) has emerged as a potential target to reverse 5-FU-resistance by inhibiting the expression of dihydropyrimidine dehydrogenase (DPD). In this study, 38 novel S1PR2 antagonists based on aryl urea structure were designed and synthesized, and the structure−activity relationship was investigated based on the S1PR2 binding assay. Representative compound 43 potently interacts with S1PR2 with a K D value of 0.73 nM. It displays potent 5-FU resensitizing activity in multiple 5-FU-resistant tumor cell lines, particularly in SW620/5-FU (EC 50 = 1.99 ± 0.03 μM) but shows no cytotoxicity in the normal colon cell line NCM460 up to 1000 μM. Moreover, 43 significantly enhances the antitumor efficacy of 5-FU in the SW620/5-FU animal model. These data suggest that 43 could be a novel lead compound for developing a 5-FU resensitizing agent.

An overview of sphingosine‐1‐phosphate receptor 2: Structure, biological function, and small‐molecule modulators

“…92 Cancer cells can also overexpress DPD after FBAL stimulation, leading to the degradation of 5-FU that enters the cells, which promotes the development of 5-FU-resistance. 93 Our previous research aimed to investigate the mechanism of intracellular DPD upregulation. We discovered that FBAL, the final metabolite of 5-FU, stimulates S1PR2 on the cancer cell surface, which in turn results in S1PR2 internalization.…”

“…We discovered that FBAL, the final metabolite of 5-FU, stimulates S1PR2 on the cancer cell surface, which in turn results in S1PR2 internalization. 93 This process leads to the upregulation of DPD expression and rapid degradation of intracellular 5-FU. Our research also identified the involvement of Jumonji domain-containing protein-3 (JMJD3) and histone H3 lysine 27 trimethylation (H3K27me3) in this process.…”

“…94 In detail, FBAL activation of S1PR2 leads to S1PR2 internalization into the endoplasmic reticulum (ER), which is correlated with the upregulation of JMJD3. 93 This process subsequently reduces the enrichment of H3K27me3 in the DPYD (DPD gene) promoter region and increases DPYD transcriptional elongation. These changes result in an increase in tumoral DPD levels, leading to the development of 5-FU resistance (Figure 8).…”

“…Our group also developed a series of diphenyl ether analogs by optimizing compound 28. 93 The predictive docking pose of compound 28 and S1PR2 indicated that the three benzene rings form a core skeleton of compound 28 that occupied the majority of the binding cavity, and the isobutyl aliphatic group was deeply inserted into a hydrophobic pocket, while the pyrrolidine and urea moieties formed hydrogen bonds or Van der Waals interactions with some conserved residues (Figure 18B). Two optimization strategies were implemented based on the binding mode.…”