Fragment-Derived Nicotinic Acid Analogues Inhibit hCA III and Downregulate CA3 Expression in HepG2 Cells

Area of Science:

• Biochemistry
• Pharmacology
• Metabolic Disorders

Background:

• Chronic oxidative stress and lipid imbalance contribute to metabolic diseases like obesity and NAFLD.
• Targeting upstream redox imbalances in key tissues remains a therapeutic challenge.
• Human carbonic anhydrase III (hCA III), a redox-associated enzyme in liver and adipose tissue, has been difficult to modulate pharmacologically.

Purpose of the Study:

• To identify novel, non-sulfonamide modulators of hCA III.
• To evaluate the cellular effects of identified hCA III modulators.

Main Methods:

• Screened 25 fragment-like nicotinic acid derivatives using an esterase activity assay.
• Confirmed compound-protein interaction using orthogonal thermal shift analysis.
• Assessed cellular effects of hit compounds in HepG2 cells, including gene expression, ROS levels, and mitochondrial membrane potential.

Main Results:

• Identified two fragment-like hCA III modulators: compound 17 (IC50 = 487 µM) and compound 22 (IC50 = 361 µM).
• Both compounds reduced *CA3* mRNA expression at 1 µM.
• Compound 22 increased reactive oxygen species (ROS) under oxidative stress, while compound 17 affected mitochondrial membrane potential.

Conclusions:

• Fragment-like nicotinic acid derivatives represent tractable starting points for hCA III modulator development.
• Identified compounds exhibit distinct cellular phenotypes, offering avenues for mechanistic investigation.
• These findings facilitate further study into the redox-linked biology of hCA III and its role in metabolic health.