Viability and oxidative response of human colorectal HCT-116 cancer cells treated with visfatin/eNampt in vitro

Visfatin/eNampt is a novel adipokine, secreted by visceral and subcutaneous fat, which could be involved in the development of obesity-associated cancer. Only few studies revealed reactive oxygen species (ROS)-dependent action of visfatin in endothelial cells, myotubes and melanoma cells. The potential pro-apoptotic properties of visfatin/eNampt in human colorectal HCT-116 cells remain unknown. The aim of the study was to examine the effects of visfatin/eNampt on cell viability along with the determination of apoptosis/necrosis extent and ROS level in HCT-116 cells. Additionally antioxidant enzymes' activities (i.e catalase (CAT), gluthatione peroxidase (GSH-Px)), and lipid peroxidation intensity in HCT-116 cells line was evaluated. Viability of HCT-116 cells was decreased after visfatin/eNampt treatment for 24 hours. The number of apoptotic cells in tested cells treated with increasing visfatin/eNampt concentrations (10, 100, 250 ng/ml) was elevated compared to untreated cells (6.4%, 9.7%, 16% vs. 3.2%; respectively). After 24 hours in the visfatin/eNampt treated group (10 - 100 ng/ml) CAT and GSH-Px activities significantly increased and this observation was accompanied by the decrease of ROS level when compared to the control group. Interestingly ROS level (using DCF detection technique) and lipid peroxidation ratio were increased in cells stimulated by visfatin/eNampt in concentration of 250 ng/ml along with the decreased activity of selected antioxidant enzymes when compared to remaining study groups, including control. We concluded that visfatin/eNampt induces decrease of cell viability and apoptosis boost in human colorectal cancer HCT-116 cells line. Visfatin/eNampt affected the level of ROS as well as antioxidant capacity, however the association of ROS level and apoptosis rate was not linear. The role for visfatin/eNampt in cancer redox status in vitro may provide a greater insight into the association between fat derived visfatin/eNampt and its endocrine action in colorectal carcinoma cells.