Influence of calcitriol on carcinogenesis and tumor progression of head and neck cancer in an in vivo immunocompetent mouse model

Introduction The antineoplastic effect of calcitriol has been proven in many tumor entities in in vitro studies. Despite impressive results regarding tumor reduction and immune stimulation, studies on the antitumor activity of calcitriol in in vivo models are lacking. The aim of the presented study was to investigate the antineoplastic potential and the immunomodulating effect of calcitriol in the immunocompetent 4NQO head and neck tumor mouse model.

Methods 36 male C57BL/6 mice were randomly assigned to three experimental arms of 12 animals each and observed over a period of 22 weeks. The animals received oral calcitriol substitution with 0 IU/kg, 5,000 IU/kg or 50,000 IU/kg in the feed ad libitum. The carcinogen 4NQO (50 μg/ml) was added to the drinking water for tumor induction up to week 12. The enoral tumor findings were documented weekly under isoflurane anesthesia. After the end of the experiment, the animals were dissected and the induced enoral tumors were analyzed with regard to size, number and extralingual extension.

Results There was a significant reduction in the number of induced oral tumors in the 50,000 IU/kg calcitriol treatment group (p<0.005) compared to the other two groups. There was also a significant reduction in the extralingual extension of the tumors (p<0.05). However, the cumulative volume of the tumors in the treatment groups showed no significant difference.

Discussion In our study, calcitriol showed a suppressive effect on the carcinogenesis of squamous cell carcinoma of the head and neck area and thus underlines its potential use in the primary prevention of head and neck cancer. The mechanisms underlying this effect will be investigated in further studies.

Publication History

Article published online:
12 May 2023