Artesunate induces apoptosis and autophagy in HCT116 colon cancer cells, and autophagy inhibition enhances the artesunate‑induced apoptosis

Abstract

The present study assessed the antitumor effect of artesunate (ART) in vitro and in vivo, as well as its underlying mechanism of action in HCT116 colon cancer cells. An MTT assay, DAPI staining, flow cytometry, western blotting, immunohistochemistry, transmission electron microscopy and TUNEL assay were performed to study the molecular mechanism underlying the antitumor effects of ART in HCT116 colon cancer cells. ART was observed to inhibit proliferation by inducing the apoptosis of HCT116 cells both in vitro and in vivo. Flow cytometry analysis demonstrated that treatment with 2 and 4 µg/ml ART for 48 h induced early apoptosis in 22.7 and 33.8% of cells, respectively. In the xenograft tumors of BALB/c nude mice, TUNEL-positive cells increased in the ART group compared with that in the normal saline group. Furthermore,the associated mitochondrial cleaved-caspase 3, poly-ADP ribose polymerase (PARP), caspase 9 and Bcl-2-associated X protein levels increased while B-cell lymphoma-2 (Bcl-2) decreased both in the cell and animal ART-treated group. ART-treated cells also exhibited autophagy induction, as evidenced by increased protein expression levels of light chain 3 (LC3) and beclin-1, and the presence of autophagosomes. Notably, pharmacological blockade of autophagy activation using hydroxychloroquine markedly enhanced ART-induced apoptosis and increased the protein levels of cleaved caspase 3 and PARP, while decreasing the levels of LC3 and beclin-1. These findings suggested that the ART-induced autophagy may have a cytoprotective effect by suppressing apoptosis. In conclusion, ART may be a potentially clinically useful anticancer drug for human colon cancer. In addition, co-treatment with ART and an autophagy inhibitor may be an effective anticancer therapy.

Sodium butyrate inhibits migration and induces AMPK‐mTOR pathway‐dependent autophagy and ROS‐mediated apoptosis via the miR‐139‐5p/Bmi‐1 axis in human bladder cancer cells

“…Furthermore, emerging studies have demonstrated a link between autophagy and apoptosis. [39][40][41][42] Atg7, an essential autophagy regulator, plays important roles in disease development and progression. 31,33 In this study, we used ATG7 siRNA and 3-MA to inhibit autophagy and explore the potential role of autophagy in NaB-induced apoptosis.…”

“…Overwhelming evidence has elucidated the intricate relationship between apoptosis and autophagy. 41,42 ATG7 has been reported to be a vital regulator in autophagy. [31][32][33] To confirm the interplay between these biological processes, we used 3-MA (3-methyladenine) and ATG7 siRNA to pharmacologically and genetically block autophagy.…”

Targeting autophagy enhances the anticancer effect of artemisinin and its derivatives

“…In the presence of an autophagy inhibitor, DHA treatment lead to more cell death. Jiang et al also reported that ART induced apoptosis and inhibited cancer proliferation in HCT116 cells both in vitro and in vivo, while treated cells exhibited the concomitant induction of autophagy. The inhibition of autophagy by hydroxychloroquine significantly enhanced ART‐induced apoptosis as indicated by enhanced levels of cleaved caspase‐3 and poly(ADP) ribose polymerase (PARP) .…”

“…Jiang et al also reported that ART induced apoptosis and inhibited cancer proliferation in HCT116 cells both in vitro and in vivo, while treated cells exhibited the concomitant induction of autophagy. The inhibition of autophagy by hydroxychloroquine significantly enhanced ART‐induced apoptosis as indicated by enhanced levels of cleaved caspase‐3 and poly(ADP) ribose polymerase (PARP) . These findings highlight the putative cytoprotective effect of autophagy in ART‐induced apoptosis and suggest that combination therapy with artemisinin and autophagy inhibitors might constitute an effective therapeutic strategy for cancer.…”

“…35 Chen et al 46 indicated by enhanced levels of cleaved caspase-3 and poly(ADP) ribose polymerase (PARP). 165 These findings highlight the putative cytoprotective effect of autophagy in ART-induced apoptosis and suggest that combination therapy with artemisinin and autophagy inhibitors might constitute an effective therapeutic strategy for cancer.…”