The oncogenic role of androgen receptors in promoting the growth of oral squamous cell carcinoma cells

Objectives The aims of this study were to examine the expression of androgen receptors ( AR ) in oral squamous cell carcinoma ( OSCC ) cells and tumors and to determine the role of AR in regulating OSCC cell growth. Materials and Methods Four OSCC cell lines were used for analyzing AR expression and transcriptional activity. The effects of AR knockdown on the growth and tumorigenicity of OSCC cells were examined. A series of 11 benign, 22 premalignant, and 21 malignant lesions of the oral cavity were used for analyzing AR expression. Results OSCC cells expressed AR proteins with differential activities. Stimulation of AR by dihydrotestosterone in OSCC cells caused an increase in cyclin D 1 expression and promoted cell growth, whereas treatment with bicalutamide led to decreased cyclin D 1 expression and inhibited cell growth. Knockdown of AR expression in OSCC cells resulted in decreased proliferation, increased apoptosis, and inhibited tumorigenicity. Results from immunohistochemical studies showed that AR immunoreactivity was found in 27% (3/11) of benign lesions, while 68% (15/22) of premalignant and 67% (14/21) of malignant lesions showed positive AR staining. Conclusion Our data suggest that OSCC cells express functional AR proteins which are critical for promoting cell growth and causing malignant disease.