Usnic Acid Inhibits Cell Proliferation Via Downregulation Of PCNA Expression In Gastric Carcinoma AGS Cells

Abstract

Usnic acid is a secondary metabolite obtained from various species of lichen. Previous studies have shown various biological activities of usnic acid, such as anti-oxidant, anti-microbial, anti-viral, anti-protozoal, anti-inflammatory, and anti-proliferative activities in different models. Its anti-proliferative activities in gastric cancer cells are still unexplored. Herein, we have investigated the effects of usnic acid on cell proliferation and viability and associated molecular alterations in human gastric carcinoma AGS cells. The treatment of usnic acid (2.5-25μM) dose-dependently reduced cell proliferation. The mRNA expression of tumor suppressor gene phosphatase tensin homolog (PTEN)in the usnic acid-treated AGS cells was increased, which may play a role in the inhibition of cell proliferation and induction of cell death. We also observed a decrease in the expression of PCNA that regulates cell proliferation by playing an important role in DNA replication. The expression of cyclin-dependent kinase inhibitor p21, which may play a role in cell cycle and proliferation inhibition was found uninfluenced with usnic acid treatment. Thus, collectively these results revealed that usnic acid inhibits the cell proliferation of AGS cells through downregulating the expression of PCNA and can be further evaluated in vivo models for its therapeutic potentials.