Discovery of JAK2/3 Inhibitors from Quinoxalinone-Containing Compounds

Area of Science:

• Medicinal Chemistry
• Pharmacology
• Computational Biology

Background:

• Janus kinases (JAKs) are crucial in cell signaling pathways implicated in T-cell and B-cell mediated diseases.
• Dysregulation of JAK2 and JAK3 is linked to the pathogenesis of lymphoid-derived diseases and leukemia.
• Targeting the JAK pathway with specific inhibitors presents a promising therapeutic strategy.

Purpose of the Study:

• To identify novel quinoxalinone-based dual inhibitors of JAK2 and JAK3 using computational and biological approaches.
• To evaluate the efficacy of identified compounds against human erythroleukemia cell lines.
• To elucidate the mechanism of action for potent inhibitors.

Main Methods:

• In-house library screening of 49 quinoxalinones using molecular docking.
• In vitro evaluation of inhibitory activity against JAK2 and JAK3.
• Assessment of antiproliferative effects on TF1 and HEL human erythroleukemia cell lines.
• Mechanistic studies including JAK2 autophosphorylation inhibition and apoptosis induction.
• Molecular dynamics simulations to understand binding interactions.

Main Results:

• ST4j demonstrated potent dual inhibition of JAK2 (IC50 = 13.00 ± 1.31 nM) and JAK3 (IC50 = 14.86 ± 1.29 nM), outperforming ruxolitinib and tofacitinib.
• ST4j effectively inhibited TF1 (IC50 = 15.53 ± 0.82 μM) and HEL (IC50 = 17.90 ± 1.36 μM) cell proliferation.
• ST4j inhibited JAK2 autophosphorylation and induced apoptosis in a dose- and time-dependent manner.
• Molecular dynamics simulations revealed ST4j stabilization via van der Waals interactions and hydrogen bonding in the JAK2 hinge region.

Conclusions:

• Quinoxalinone derivatives, particularly ST4j, are effective dual inhibitors of JAK2/3.
• ST4j exhibits significant therapeutic potential for treating lymphoid-derived diseases and leukemia cancer.
• Further investigation of ST4j as a novel therapeutic agent is warranted.