Discovery, structure-activity relationship study and biological evaluation of 2-thioureidothiophene-3-carboxylates as a novel class of C-X-C chemokine receptor 2 (CXCR2) antagonists.

The C-X-C motif ligand 8 and C-X-C chemokine receptor 2 (CXCL8-CXCR2) axis is involved in pathogenesis of various diseases including inflammation and cancers. Various CXCR2 antagonists are under development for several diseases. Our previous high-throughput cell-based assay specific for CXCR2 has identified a pyrimidine-based compound CX797 acting on CXCR2 down-stream signaling. A lead optimization campaign through scaffold-hopping strategy led to a series of 2-thioureidothiophene-3-carboxylates (TUTP) as novel CXCR2 antagonists. Structure-activity relationship study of TUTPs led to the identification of compound 52 that significantly inhibited CXCR2-mediated β-arrestin recruitment signaling (IC ₅₀  = 1.1±0.01 μM) with negligible effect on CXCL8-mediated cAMP signaling and calcium flux. Similar to the known CXCR2 antagonist SB265610, compound 52 inhibited CXCL8-CXCR2 induced phosphorylation of ERK1/2. TUTP compounds also inhibited CXCL8-mediated cell migration and showed synergy with doxorubicin in ovarian cancer cells, thereby supporting TUTPs as promising compounds for cancer treatment.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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