Calcitriol down-regulates human ether a go-go 1 potassium channel expression in cervical cancer cells.

Background/aim: Human ether à-go-go-1 (EAG1) potassium channels are promising anticancer targets. Calcitriol has antitumoural properties. This study investigated EAG1 regulation by calcitriol in normal and cancer cells.

Materials And Methods: Cancer cell lines from cervix, prostate, mammary gland, and normal placenta trophoblasts were cultured. Calcitriol was determined by HPLC. Gene and protein expression were assessed by real-time RT-PCR and western blot analysis, respectively. Calcitriol-synthesising enzyme CYP27B1 or vitamin D receptor (VDR), were transfected in cervical cancer SiHa cells. Cell proliferation was assayed with XTT.

Results: Calcitriol decreased EAG1 mRNA in all cell types, and EAG1 protein and proliferation in SiHa cells. VDR antagonist ZK-159222 prevented the calcitriol effect on EAG1 mRNA. CYP27B1-transfected cells produced more calcitriol and less EAG1 mRNA. EAG1 mRNA was more potently inhibited by calcitriol in VDR-transfected cells.

Conclusion: EAG1 is a calcitriol target in normal and cancer cells and calcitriol is a potential therapy for cervical cancer.