Antitumor Effect of Shikonin, a PKM2 Inhibitor, in Cholangiocarcinoma Cell Lines

Abstract

Background/aim: Pyruvate kinase M2 (PKM2) is an enzyme that is predominantly overexpressed in various types of cancer. The role of PKM2 in liver fluke-associated cholangiocarcinoma (CCA) remains unclear. This study aimed to investigate the antitumor activity of shikonin, a PKM2 inhibitor, in CCA cells.

Materials and methods: Immunohistochemistry and immunoblotting were used to determine PKM2 expression in CCA tissues and cells. Antiproliferative effects of shikonin were evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, colony-formation and trypan blue exclusion assays. The anti-metastatic activity of shikonin was determined using the Boyden chamber assay. Mechanisms by which shikonin inhibited CCA progression were determined.

Results: PKM2 was overexpressed in CCA compared to normal bile duct epithelial cells. Shikonin significantly inhibited growth, and migration of CCA cells while inducing their death. A mechanistic study revealed that antitumor effects of shikonin in CCA cells depended on increased production of reactive oxygen species.

Conclusion: Shikonin may be a novel therapeutic agent for patients with CCA.

Keywords: Cholangiocarcinoma; pyruvate kinase M2; reactive oxygen species; shikonin.