Shikonin is the main component of root extracts from the Chinese herbal medicine Lithospermum erythrorhizon, which is commonly used for the treatment of various diseases including
cancer. Previous research showed that
shikonin suppressed
pancreatic cancer growth; nevertheless, its molecular targets and mechanisms have not been elucidated. This study aimed to investigate the interaction and regulatory mechanisms of
shikonin on its potential target
p21-activated kinase 1 (PAK1). Through a labchip-based screening method,
shikonin was identified as a potential bioactive PAK1 inhibitor. Molecular docking technology was used to detect the interaction sites of
shikonin and
PAK1 kinase. Western blot was performed to validate the mechanism. MTT and flow cytometry were practiced to investigate the effect of
shikonin against
pancreatic cancer cells. The results show that
shikonin significantly inhibited the activity of
PAK1 kinase with IC50 value of 7.252 ± 0.054 μM. Molecular docking studies showed that
shikonin binds to the
ATP-binding pocket of the
PAK1 kinase domain. Moreover,
shikonin inhibited PAK1 activation and its downstream signaling pathway
proteins, while reducing proliferation and inducing apoptosis of
pancreatic cancer cells. Further studies showed that the treatment of
shikonin sensitized
pancreatic cancer cells to chemotherapeutic drugs. These results suggest that
shikonin, a potential natural inhibitor targeting
PAK1 kinase, has promising potent applications in the treatment of
pancreatic cancer and
chemotherapy sensitization.