Chrysophanic Acid Induces Necrosis but not Necroptosis in Human Renal Cell Carcinoma Caki-2 Cells

Choi, Joon Seok

Abstract

BACKGROUND
Chrysophanic acid, also known as chrysophanol, has a number of biological activities. It enhances memory and learning abilities, raises superoxide dismutase activity, and has anti-cancer effects in several model systems. According to previous reports, chrysophanic acid-induced cell death shares features of necrotic cell death. However, the molecular and cellular processes underlying chrysophanic acid-induced cell death remain poorly understood.
METHODS
Chrysophanic acid-induced cell death was monitored by cell viability assay and Annexin V-propidium iodide (PI) staining of renal cell carcinoma Caki-2 cells. The induction of intracellular reactive oxygen species (ROS) by chrysophanic acid and the suppression of ROS by anti-oxidants were evaluated by 2',7'-dichlorofluorescin diacetate staining. The expression and phosphorylation of proteins that are involved in apoptosis and necroptosis were detected by immunoblotting.
RESULTS
The extent of chrysophanic acid-induced cell death was concentration and time dependent, and dead cells mainly appeared in the PI-positive population, which is a major feature of necrosis, upon fluorescence-activated cell sorting analysis. Chrysophanic acid-induced cell death was associated with the generation of intracellular ROS, and this effect was reversed by pretreatment with N-acetyl cysteine. Chrysophanic acid-induced cell death was not associated with changes in apoptotic or necroptotic marker proteins.
CONCLUSIONS
The cell death induced by chrysophanic acid resembled neither apoptotic nor necroptotic cell death in human renal cell carcinoma Caki-2 cells.