Dihydroartemisinin Suppresses Esophageal Squamous Cell Carcinoma by Downregulating COX-2 through the ROS/MAPK/Sp1 Pathway.

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) has a poor prognosis due to its aggressiveness and chemoresistance, necessitating novel therapeutic strategies. Dihydroartemisinin (DHA), an artemisinin derivative, exhibits broad anticancer activity, but its mechanism in ESCC remains incompletely understood.

METHODS

Transcriptomic sequencing identified differentially expressed genes upon DHA treatment. The regulation of COX-2 by DHA was validated via RT-qPCR and Western blot. Gain- and loss-of-function assays assessed COX-2 and Sp1 effects on ESCC proliferation and migration. Dual-luciferase reporter assays confirmed Sp1-driven COX-2 transcription. ROS levels and MAPK pathway protein expression were measured by flow cytometry and Western blot, respectively. A xenograft model evaluated in vivo effects of Sp1 overexpression and DHA.

RESULTS

DHA downregulated COX-2 in a time- and dose-dependent manner, inhibiting ESCC cell proliferation and migration. Sp1 directly bound the COX-2 promoter and positively regulated its expression, thereby promoting malignant phenotypes. DHA triggered ROS accumulation and downregulated the protein levels of MAPK (ERK/MSK), Sp1, and COX-2. Both NAC (an antioxidant) and Sp1 overexpression reversed these effects. In vivo, DHA significantly suppressed tumor growth via the Sp1/COX-2 axis without detectable toxicity.

CONCLUSION

This study establishes that DHA inhibits ESCC proliferation and metastasis through the ROS-MAPK(ERK/MSK)-Sp1-COX-2 axis, highlighting DHA as a promising repurposed agent and identifying Sp1/COX-2 as novel therapeutic targets for ESCC.