Structure-Based Design of 4-(1-Methyl-1H-indol-3-yl)pyrimidin-2-amine Derivatives as the First Covalent FGFR3...

Area of Science:

• Oncology
• Medicinal Chemistry
• Molecular Biology

Background:

• Aberrant fibroblast growth factor receptor 3 (FGFR3) activation is a key driver in human bladder carcinogenesis.
• Existing pan-FGFR inhibitors lack FGFR3 isoform selectivity and are ineffective against acquired resistance mutations like FGFR3 V555M/L.

Purpose of the Study:

• To design and synthesize novel, selective, covalent FGFR3 inhibitors.
• To address limitations of current therapies, including lack of selectivity and resistance mechanisms.

Main Methods:

• Structure-based drug design of 4-(1-methyl-1H-indol-3-yl)pyrimidin-2-amine derivatives.
• In vitro assays to determine inhibitory concentrations (IC50) against FGFR3 and related kinases.
• Testing against FGFR3 V555M resistance mutation and in FGFR3-driven cancer cells (RT112/84).
• Structural characterization via MALDI-TOF-MS and X-ray crystallography.
• In vivo evaluation in a bladder cancer xenograft model.

Main Results:

• Compound 10s demonstrated high potency against FGFR3 (IC50 = 6.8 nM) with 5-60 fold selectivity over FGFR1/2/4.
• 10s effectively inhibited the FGFR3 V555M resistance mutation (IC50 = 19.2 nM).
• Significant antiproliferative effects were observed in RT112/84 cells (IC50 = 9.2 nM).
• Covalent binding of 10s to FGFR3 was confirmed structurally.
• Compound 10s showed significant antitumor efficacy in vivo.

Conclusions:

• The developed 4-(1-methyl-1H-indol-3-yl)pyrimidin-2-amine derivatives represent the first selective covalent FGFR3 inhibitors.
• Compound 10s is a promising candidate for FGFR3-targeted bladder cancer therapy, addressing both selectivity and resistance challenges.