Structure-activity relationship of 3,5-diaryl-2-aminopyridine ALK2 inhibitors reveals unaltered binding affinity for...

Area of Science:

• Biochemistry
• Pharmacology
• Oncology

Background:

• Fibrodysplasia ossificans progressiva (FOP) and diffuse intrinsic pontine glioma (DIPG) are severe diseases with no effective treatments.
• Activating mutations in ACVR1, which encodes the BMP type I receptor kinase ALK2, cause FOP and are found in some DIPG tumors.

Purpose of the Study:

• To explore the structure-activity relationship of novel 2-aminopyridine-based ALK2 inhibitors.
• To identify potent and selective ALK2 inhibitors for potential therapeutic development against FOP and DIPG.

Main Methods:

• Synthesized and evaluated a series of novel 2-aminopyridine derivatives.
• Assessed compound potency using kinase, thermal shift, and cell-based BMP signaling assays.
• Determined selectivity against related BMP and TGF-β type I receptor kinases.
• Evaluated in vitro cytotoxicity and binding affinity to wild-type and mutant ALK2 proteins.

Main Results:

• Several modifications enhanced inhibitor potency and selectivity for ALK2.
• A potent 2-methylpyridine derivative (LDN-214117) demonstrated high ALK2 selectivity and low cytotoxicity.
• Inhibitor efficacy was consistent across wild-type and mutant ALK2 proteins, irrespective of potential conformational changes.
• Cytotoxicity was not correlated with inhibitory potency or selectivity, suggesting alternative mechanisms.

Conclusions:

• Novel ALK2 inhibitors, particularly LDN-214117, show potential for preclinical development.
• BMP inhibitors targeting wild-type ALK2 signaling are likely effective against diverse ALK2 mutant proteins in FOP and DIPG.
• These findings offer a promising therapeutic strategy for FOP and DIPG.