Plumbagin Suppresses Growth, Induces Apoptosis, and Inhibits Migration in Cholangiocarcinoma via Reactive Oxygen Species Generation and Mitochondrial Function

Abstract

Objectives: Plumbagin has been displayed on growth inhibition in several cancer cells; however, the anticancer effects of plumbagin on cholangiocarcinoma (CCA) cell are still less information. This article will explore the potential anticancer effects and underlying mechanisms of plumbagin on CCA cells. Materials and Methods: Two types of CCA cell, including KKU-100 with slow growth and migration and KKU-M452 with rapid growth and migration, were treated with plumbagin and measured the growth inhibition and migratory suppression by sulforhodamine B, colony formation, acridine orange/ethidium bromide staining, wound healing, and Matrigel migration. Apoptosis induction, reactive oxygen species (ROS) formation, and mitochondrial function were analyzed by the flow cytometric method. Results: To compare the plumbagin effects on two types of CCA cells, the data indicated that plumbagin strongly reduced cell proliferation in a concentration- and time-dependent manner. At 72 h, IC50 values were 1.11 ± 0.12 µM for KKU-100 and 2.52 ± 0.40 µM for KKU-M452 cells, with inhibition of the cell cycle in the G0/G1 phase for KKU-100 and the G2/M phase for KKU-M452, respectively. Moreover, plumbagin decreased cell migration in both CCA cells in a dose-dependent manner. Furthermore, late apoptosis was significantly induced after treatment with plumbagin. Mechanistically, plumbagin increased ROS along with decreased mitochondrial function in CCA cells. Finally, the position of 5-hydroxy on the naphthoquinone ring of plumbagin was in a good position to form an H-bond with the amino group for all caspase 3, cytochrome C, and p21 binding sites, and these data indicated that plumbagin suppressed CCA cells via modulation of these proteins. Conclusion: Plumbagin strongly suppresses cell viability and stimulates apoptosis in CCA cells via induction of ROS and inhibition of mitochondrial function.