Aim
Artemisinin and its derivatives are not only approved antimalarial drugs but also exert strong anticancer activity. Based on the clinical activity of artesunate (ART) that has been previously reported in cervix carcinoma, we investigated a panel of 12 different biomarkers and identified the Wilms Tumor 1 (WT1) protein as a potential target of ART. Patients and
Conclusion
WT1 may represent a novel target of ART in cancer cells that contribute to the response of tumor cells to this drug.
Methods
Matched biopsies of cervical carcinoma before, during, and after therapy from patients treated with ART were investigated for induction of apoptosis (TUNEL assay) and expression of Wilms Tumor protein 1 (WT1), 14-3-3 ζ, cluster of differentiation markers (CD4, CD8, CD56), ATP-binding cassette transporter B5 (ABCB5), glutathione S-transferase P1 (GSTP1), inducible nitric oxide synthase (iNOS), translationally controlled tumor protein (TCTP), eukaryotic elongation factor 3 (eIF3), and ADP/ATP translocase by immunohistochemistry. WT1 has been selected for more detailed analyses using molecular docking in silico, microscale thermophoresis using recombinant WT1, and cytotoxicity testing (resazurin assay) using HEK293 cells transfected with four different WT1 splice variants.
Results
The fraction of apoptotic cells and the expression of WT1, 14-3-3 ζ, and CD4 increased upon ART treatment in tumors of patients. ART was bound in silico to a domain located at the DNA-binding site of WT1, while dihydroartemisinin (DHA) was bound with low affinity to a different site of WT1 not related to DNA-binding. The results were verified using microscale thermophoresis, where ART but not DHA bound to recombinant WT1. Transfectants overexpressing different WT1 splice variants exerted low but significant resistance to ART (≈2-fold).