Enhanced apoptosis of HCT116 colon cancer cells treated with extracts from Calotropis gigantea stem bark by starvation
Orakot Simanurak,
Dumrongsak Pekthong,
Julintorn Somran,
Apirath Wangteeraprasert,
Metawee Srikummool,
Naphat Kaewpaeng,
Supawadee Parhira,
Piyarat Srisawang
Affiliations
Orakot Simanurak
Department of Physiology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand
Dumrongsak Pekthong
Department of Pharmacy Practice, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok 65000, Thailand; Center of Excellence for Innovation in Chemistry, Naresuan University, Phitsanulok 65000, Thailand; Center of Excellence for Environmental Health and Toxicology, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok, 65000, Thailand
Julintorn Somran
Department of Pathology, Faculty of Medicine, Naresuan University, Phitsanulok, 65000, Thailand
Apirath Wangteeraprasert
Department of Medicine, Faculty of Medicine, Naresuan University, Phitsanulok 65000, Thailand
Metawee Srikummool
Department of Biochemistry, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand
Naphat Kaewpaeng
Center of Excellence for Innovation in Chemistry, Naresuan University, Phitsanulok 65000, Thailand; Department of Pharmaceutical Chemistry and Pharmacognosy, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok 65000, Thailand
Supawadee Parhira
Center of Excellence for Innovation in Chemistry, Naresuan University, Phitsanulok 65000, Thailand; Center of Excellence for Environmental Health and Toxicology, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok, 65000, Thailand; Department of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok 65000, Thailand; Corresponding author. Department of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok 65000, Thailand.
Piyarat Srisawang
Department of Physiology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand; Center of Excellence for Innovation in Chemistry, Naresuan University, Phitsanulok 65000, Thailand; Center of Excellence in Medical Biotechnology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand; Corresponding author. Department of Physiology, Faculty of Medical science, Naresuan University, Phitsanulok 65000, Thailand.
Calotropis gigantea stem bark extract, particularly the dichloromethane fraction (CGDCM), demonstrated the most potent antiproliferative effects on hepatocellular carcinoma HepG2 and colorectal HCT116 cells. The current study focused on enhancing the effectiveness of cancer treatment with CGDCM at concentrations close to the IC50 in HCT116 cells by reducing their nutrient supply. CGDCM (2, 4, and 8 μg/mL) treatment for 24 h under glucose conditions of 4.5 g/L without fetal bovine serum (FBS) supplementation or serum starvation (G+/F−), glucose 0 g/L with 10% FBS or glucose starvation (G−/F+), and glucose 0 g/L with 0% FBS or complete starvation (G−/F−) induced a greater antiproliferative effect in HCT116 cells than therapy in complete medium with glucose 4.5 g/L and 10% FBS (G+/F+). Nonetheless, the anticancer effect of CGDCM at 4 μg/mL under (G−/F−) showed the highest activity compared to other starvation conditions. The three starvation conditions showed a significant reduction in cell viability compared to the control (G+/F+) medium group, while the inhibitory effect on cell viability did not differ significantly among the three starvation conditions. CGDCM at 4 μg/mL in (G−/F−) medium triggered apoptosis by dissipating the mitochondrial membrane potential and arresting cells in the G2/M phase. This investigation demonstrated that a decrease in intracellular ATP and fatty acid levels was associated with enhanced apoptosis by treatment with CGDCM at 4 μg/mL under (G−/F−) conditions. In addition, under (G−/F−), CGDCM at 4 μg/mL increased levels of reactive oxygen species (ROS) and was suggested to primarily trigger apoptosis in HCT116 cells. Thus, C. gigantea extracts may be useful for the future development of alternative, effective cancer treatment regimens.
