Dihydroartemisinin-Induced Apoptosis is Associated with Inhibition of Sarco/Endoplasmic Reticulum Calcium ATPase Activity in Colorectal Cancer

Abstract

Dihydroartemisinin (DHA) is a promising anti-cancer compound capable of inhibiting proliferation and inducing apoptosis of various cancer cells, including colorectal cancer. However, the molecular mechanisms have not been well understood. This study aimed to explore the underlying mechanism of DHA-induced apoptosis in HCT-116 cells. Cell counting kit-8 assay and flow cytometry analysis confirmed that DHA inhibited proliferation, arrested cell cycle at G0/G1 phase, and enhanced apoptosis in HCT-116 cells. Fluo-3/AM-stained flow cytometry assay revealed that the intracellular Ca(2+) concentration of HCT-116 cells was increased significantly after DHA treatment. Meanwhile, the activity of sarco/endoplasmic reticulum calcium ATPase (SERCA) was appeared to be reduced in a dose-dependent manner. We further detected the upregulated expression of CAAT/enhancer binding protein homologous protein (CHOP) in DHA-treated HCT-116 cells. Conversely, silencing CHOP resulted in a decrease of DHA-induced apoptosis. In addition, the expression of Bax in cytoplasm was elevated significantly along with the sharply decline of Bcl-2 expression in DHA-treated HCT-116 cells. Moreover, the distributions of Bid on mitochondria were increased, accompanied by the activation of caspase-3 in the presence of DHA. Overall, our data indicated that DHA triggered endoplasmic reticulum (ER) stress through inhibiting SERCA activity to release intracellular Ca(2+) from ER, the upregulated expression of CHOP activated mitochondrial apoptosis pathway to induce apoptosis of HCT-116 cells. Therefore, our findings provide a theoretical foundation for DHA as a potential candidate in treatment of colorectal cancer.

Dihydroartemisinin Exerts Anti-Tumor Activity by Inducing Mitochondrion and Endoplasmic Reticulum Apoptosis and Autophagic Cell Death in Human Glioblastoma Cells

“…Our results showed that Z-VAD or 3-MA partly blocked the inhibitory effect of DHA on the cell viability, and Z-VAD combined with 3-MA completely rescued this effect, suggesting that the cytotoxic effects of DHA on human GBM cells was associated with cell apoptosis and autophagy. Consistent with our results, recent studies found that DHA induced apoptosis in human gastric cancer and colorectal cancer cells (Lu et al, 2015 ; Zhang et al, 2017 ), and effectively inhibited cell growth and induced apoptosis in human BT325 glioma cells and rat C6 glioma cells (Du et al, 2015 ). Furthermore, DHA possessed cytotoxic effects by inducing autophagy in human leukemia K562 cells and pancreatic cancer cells (Wang et al, 2012 ; Jia et al, 2014 ).…”

“…DHA up-regulated ROS to increase ferrous ion in cells, and contributed to the apoptosis of human lung carcinoma cells (Xu C. C. et al, 2016 ). DHA increasing ROS resulted in the accumulation of intracellular Ca 2+ , and promoted the mitochondria and ER stress pathway of apoptosis in human colorectal cancer cells (Lu et al, 2015 ). Furthermore, previous study found that DHA induced autophagy and inhibited the growth of iron-loaded human myeloid leukemia cells via ROS toxicity.…”

New frontiers in the treatment of colorectal cancer: Autophagy and the unfolded protein response as promising targets

“…Similarly, dihydroartemisinin chemotherapy induces mitochondria-dependent apoptosis via ER stress pathways in CRC HCT116 cells 162 . The ERN1-XBP1 pathway is also important for promotion and progression of CRC 163 .…”

Heme-Dependent ER Stress Apoptosis: A Mechanism for the Selective Toxicity of the Dihydroartemisinin, NSC735847, in Colorectal Cancer Cells

“…The cytotoxicity of artemisinin-type molecules has also been linked to the endoplasmic reticulum (ER) stress pathway (18)(19)(20)(21). ER stress occurs when the load of unfolded proteins exceeds the protein folding capacity of the cell (22).…”